Patent Publication Number: US-7717868-B2

Title: Chair-type massaging apparatus, cover for massaging apparatus, cover for leg rest, and massaging apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This is a national phase of PCT Application No. PCT/JP2004/006281 filed Apr. 30, 2004, which claims priority to Japanese Application No. 2003-148173 filed May 26, 2003, Japanese Application No. 2003-184464 filed Jun. 27, 2003, Japanese Application No. 2003-331423 filed Sep. 24, 2003, and Japanese Application No. 2003-379329 filed Nov. 10, 2003, the entire disclosures of each of which are hereby incorporated by reference into the present application. 
   TECHNICAL FIELD 
   The present invention relates to a chair-type massaging apparatus configured to massage a body of a user. More particularly, the present invention relates to a chair-type massaging apparatus provided with a leg rest on which lower legs of the user are supported. The present invention also relates to a cover for the massaging apparatus or the leg rest that is configured to massage legs and other areas of the body, and a massaging apparatus provided with these covers. 
   BACKGROUND 
   Massaging apparatuses configured to apply stimulation to a body of a user, such as kneading, tapping, finger pressure, and rolling, are widely known. There are a variety of massaging apparatuses, such as chair-types and mattress-types, among which the chair-type massaging apparatus has been highly demanded and widely used because it is capable of massaging the user in a relaxed posture and its installation area is smaller than that of the mattress-type. 
   Most of the conventional chair-type massaging apparatuses are typically configured to apply pressing stimulation to a back and a shoulder of the user. In order to enable the user to efficiently obtain effects such as facilitation of blood circulation, recovery from fatigue, or relaxation, it is important to massage physical parts such as the legs and arms of the user. In recent years, chair-type massaging apparatuses capable of massaging arms and legs have been developed. 
   One type of chair-type massaging apparatus comprises a chair body (massage chair) and a leg rest (lower leg massager) provided with two concave receiver portions on which fight and left lower legs of the user are supported (see Japanese Patent No. 3012127). This chair-type massaging apparatus is constructed such that air bags are provided on opposite side surfaces of each concave receiver portion, and the air bags expand and contract to allow a calf of a leg of the user to be massaged with the calf sandwiched from right and left sides. 
   The chair-type massaging apparatus disclosed in Japanese Patent No. 3012127 is constructed such that the chair body is separated from the leg rest, while in Japanese Patent No. 3012780, the leg rest is attached to the chair body. In the latter construction, the leg rest is attached to a front side of a seat portion of the chair body. The user is seated in the chair body and thereby the lower legs of the user are placed on the leg rest. In the chair-type massaging apparatus disclosed in Japanese Patent No. 3012780, as in the chair-type massaging apparatus disclosed in Japanese patent No. 3012127, the leg rest is provided with concave receiver portions and right and left lower legs are placed on the concave portions to be massaged (see Japanese Patent Publication No. 3012780). 
   Some mattress-type massaging apparatuses are capable of massaging lower legs of the user. One type of such mattress-type massaging apparatus provides double air bags on both sides of each of right and left calves of the legs of the user lying on his or her back (see Japanese Laid-Open Patent Application Publication No. Hei. 10-57436 and Japanese Laid-Open Patent Application Publication No. Hei. 10-118143). This mattress-type massaging apparatus is capable of massaging the right and left calves of the user by expansion and contraction of the air bags with the calves sandwiched and retained from right and left sides; this mattress-type massaging apparatus is also capable of increasing the force to sandwich and retain the calves by expanding the dual air bags simultaneously. 
   However, in the chair-type massaging apparatuses disclosed in Japanese Patent Nos. 3012127 and 3012780, when the user puts his or her calves into the concave receiver portions, the posture of the user is restricted and obstructed by side walls of the concave receiver portions. This makes it difficult for the user to assume a desired posture. 
   In the chair-type massaging apparatus disclosed in Japanese Patent No. 3012780, the lower legs can remain outside the concave receiver portions with the user seated therein. In this case, the leg rest may become an obstruction, making it difficult for the user to assume a desired posture. 
   It is known that there exist a plurality of acupuncture points called “sanri” and “horyu” in an outer region of a shin of a lower leg of a body, i.e., in a front outer region of the lower leg, and function to provide adjustment of various internal organs as well as to provide effects such as facilitation of blood circulation, recovery from fatigue, or relaxation by applying stimulation to these regions. But, the chair-type massaging apparatuses disclosed in above Japanese Patent Publications Nos. 3012127 and 3012780 are incapable of massaging the outer region of the shin. 
   The inventions disclosed in Japanese Laid-Open Patent Application Publication Nos. Hei. 10-57436 and 10-118143 are applicable to the leg rest of the chair-type massaging apparatus. Since the front surface of the leg rest is substantially flat when each air bag is contracted, the user easily assumes a desired posture. However, the chair-type massaging apparatus of such a construction is incapable of massaging the outer region of the shin. 
   Since the invention disclosed in Japanese Laid-Open Patent Application Publication No. Hei. 10-57436 is not a chair-type massaging apparatus but a mattress-type massaging apparatus, the user must lie on a mattress, and the lower leg is incapable of being massaged with the user seated in the chair. 
   In the inventions disclosed in Japanese Laid-Open Patent Application Publication Nos. Hei. 10-57436 and 10-118143, since the mattress portion is substantially flat with the air bag contracted, there is no protruding portion that restricts or obstructs the posture of the user in such a contracted state. However, since a protrusible and retractable system of the massaging apparatus is constructed such that the air bag, substantially flat in a retracted state, protrusively expands from the lower side of the lower leg, setting a pressing angle or a pressing position with respect to the lower leg in a limited range, and therefore, a massage pattern is very limited. In addition, since the air bags or cloth covers which cover these air bags protrude and are flexible, the precision of the pressing position or the pressing angle is not high. 
   Some massaging apparatuses are configured to massage the body of the user in such a manner that a massaging system such as massaging elements protrudes and retracts with respect to the body of the user to apply pressure to the body. 
   A cover that covers a massaging system provided with the protrusible and retractable system is disclosed in Japanese Laid-Open Patent Application Publication No. Hei. 8-112330. The cover covers a side surface of a massaging system causing a pressing drive plate having a pressing element to protrude and retract by expansion and contraction of air cells (air bags). One sheet (continuous sheet without seams or joints) is bent in a bellows-like manner, and an elastic material such as rubber is stitched inside. The bellows-like sheet expands with extension of the elastic material during expansion of the air cell and is folded by contraction of the elastic material during contraction of the air cell (see Japanese Laid-Open Patent Application Publication No. Hei. 8-112330). 
   The cover disclosed in Japanese Laid-Open Patent Application Publication No. 8-112330 is configured not to cover a body side of the massaging system but to cover a side surface of the massaging system so as not to interfere with the body side. On the other hand, the cover disclosed in Japanese Laid-Open patent Application Publication No. Hei-10-295753 is configured to cover the body side of the massaging system and is made of an elastic material such as an elastic cloth or rubber sheet. Such an elastic material enables the cover to expand and contract according to protrusion and retraction of the massaging system with respect to the body of the user (see Japanese Laid-Open patent Application Publication No. 10-295753). 
   In the massaging apparatus disclosed in Japanese Laid-Open Patent Application Publication No. Hei. 8-112330, a foldable portion of the cover which is folded during contraction of the air cell (retraction of the massaging system) is not located on the side of a support surface on which a body of the user who is being massaged is supported, but at a position of the side surface which is away from the support surface side. Therefore, this cover does not cover the support surface on which the body of the user is supported. This cover is not configured for protrusion and retraction operation of a massaging apparatus that protrudes and retracts within the support surface on which the body of the user is supported. 
   Japanese Laid-Open Patent Application Publication No. Hei. 10-295753 discloses a cover made of an elastic material as a cover which is capable of covering the body side of the massaging system having the protrusible and retractable system and is configured for protrusion and retraction operation. However, the elastic material decreases elasticity after repeated expansion and compression during use. As a result, the cover becomes deformed, and its external appearance degrades. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a chair-type massaging apparatus that enables a user to assume a desired posture without restriction of the lower legs in a seated state. 
   Another object of the present invention is to provide a chair-type massaging apparatus that enables pressing angles or pressing positions with respect to the lower legs to be set freely and precisely. 
   Another object of the present invention is to provide a chair-type massaging apparatus that is capable of massaging the outer regions of shins of the lower legs of the user. 
   A further object of the present invention is to provide a cover configured to accommodate protruding and retracting operations within a support surface on which a body of the user is supported while maintaining its external appearance, and a massaging apparatus using this cover. 
   In order to achieve the above mentioned objects, a chair-type massaging apparatus of the present invention comprises a leg rest including a support portion configured to support a lower leg of a user; and an expandable portion which is protrusible forward from the support portion to press the lower leg of the user and is retractable; wherein the leg rest is configured such that the support portion and the expandable portion form a substantially flat surface with the expandable portion retracting. 
   In the above invention, the expandable portion may include a massaging portion which is protrusible to press the lower leg of the user and is retractable; and protrusible portions which are mounted at sides in the rightward and leftward direction of the support portion and are configured to be protrusible to rise up inward in the rightward and leftward direction and to be retractable. The massaging portion may be mounted on each of the protrusible portions; and with the protrusible portion and the massaging portion retracting, elements of the support portion which are located inward relative to the protrusible portion in the rightward and leftward direction and the massaging portion may form a substantially flat surface. 
   In the chair-type massaging apparatus, the lower legs are massaged with the user seated therein. With the protrusible portion and the massaging portion retracted, since the protrusible portion, elements of the support portion which are located inward relative to the protrusible portion in the rightward and leftward direction, and the massaging portion form a substantially flat surface, the protrusible portions located on both sides in the rightward and leftward direction and the elements located inward in the rightward and leftward direction are substantially flat, and hence do not disturb the user. Furthermore, since the massaging portion, which is configured to protrude and retract, is mounted on the protrusible portions protrusible to rise up inward in the rightward and leftward direction, the pressing angles or the pressing positions with respect to the lower legs of the user can be set quite freely. By combining protruding angles of the protrusible portion, protruding angles or positions of the massaging portion in various ways, the pressing angles or the pressing positions with respect to the lower legs of the user which are set quite freely. Since the protrusible portion, which is a base of the massaging portion, is a part of the support portion, and since the support portion is deformable, positional or angular displacement of the massaging portion is minimized. As a result, the pressing angles or the pressing positions are set with high precision. 
   Preferably, in the above invention, each of the protrusible portions may include a receiver plate; and the receiver plate may be rotatable around a first rotational axis positioned on the inner side thereof in the rightward and leftward direction and may be configured to rotate by expansion and contraction of an air bag placed on a rear surface side of the receiver plate. 
   In such a construction, the structure of the protrusible portion, which is protrusible to rise up inward in the rightward and leftward direction and is retractable, is simplified. As a result, a small-sized and lightweight chair-type massaging apparatus is achieved, and manufacturing costs or component costs may be reduced. 
   Preferably, the massaging portion may include a massaging plate; and the massaging plate may be rotatable around a second rotational axis positioned on inner side thereof in the rightward and leftward direction, and may be configured to rotate by expansion and contraction of an air bag placed between the receiver plate and the massaging plate. In such a construction, a structure of the massaging portion which is positioned on the protrusible portion and configured to protrude inward in the rightward and leftward direction to press the lower leg and is retractable is simplified. As a result, a small-sized and lightweight chair-type massaging apparatus is achieved, and manufacturing costs or component costs may be reduced. 
   Preferably, the first rotational axis and the second rotational axis may be provided at different positions. 
   In this case, because of the positional relationship between these axes, the position or the protruding angle of the massaging plate is set more freely, and the pressing angles or the pressing positions with respect to the lower legs of the user which are set quite freely. 
   In this case, preferably, the air bag configured to cause the receiver plate or the massaging plate to protrude and retract is expandable in a substantially fan-shaped form in cross-section, and is placed in such a manner that a center of the fan-shaped form is positioned on the inner side in the rightward and leftward direction of the support portion. In such a construction, since the rotational axis (first or second rotational axis) of the receiver plate or the massaging plate and the center of the fan-shaped form of the air bag are positioned on the same side in the rightward and leftward direction to be close to each other, the plates are caused to rotate very efficiently by expansion and contraction of the air bag. 
   In the above invention, the support portion may further comprise an intermediate massaging portion including an intermediate air bag that is mounted in an intermediate region in the rightward and leftward direction of the support portion and is configured to protrude and retract, and with the protrusible portion, the massaging portion, and the intermediate massaging portion retracted, the elements of the support portion which are located inward relative to the protrusible portion in the rightward and leftward direction and the massaging portion may form a substantially flat surface. In such a construction, since the lower leg is sandwiched between the massaging portion mounted on the protrusible portion and the intermediate massaging portion, it is massaged effectively or strongly. Furthermore, in retraction of the intermediate massaging portion or other elements, the protrusible portion and the elements located inward relative to the protrusible portion in the rightward and leftward direction become substantially flat, and as a result, the user is not disturbed. 
   In this case, the intermediate massaging portion may include air bags. The air bags may be positioned to be symmetric in the rightward and leftward direction with respect to an axis located at a center in the rightward and leftward direction of the support portion. The air bags may be each expandable in a substantially fan-shaped form in cross-section and are each placed in such a manner that a center of the fan-shaped form is positioned on the outer side in the rightward and leftward direction of the support portion. 
   In such a construction, since the air bags are configured to expand to fall toward the right and left legs, the intermediate massaging portion is capable of efficiently pressing the right and left lower legs from inward in the rightward and leftward direction. The center massaging portion is simply constructed of the air bags, and becomes substantially flat in retraction of the intermediate massaging portion and other elements. 
   In the above invention, the support portion may have a support surface on which the lower leg of the user is supported, the expandable portion may include a massaging portion configured to press the lower leg of the user, the massaging portion may include an air bag configured to expand and contract by inflowing and outflowing air with respect to the air bag, the air bag in a contracted state and the support surface may form a substantially flat surface, and the air bag in an expanded state may be configured to press an outer region of a shin of the lower leg of the user substantially backward. 
   In such a construction, since the front side of the leg rest is substantially flat with the air bag expanded, the user may take a desired posture without restriction of the lower legs of the user in a seated state. In addition, the massaging portion may massage the outer region of the shin of the lower leg of the user. 
   In this case, preferably, the massaging portion may include massaging portions which are respectively mounted on both end portions of the support portion so as to correspond to fight and left lower legs of the user. 
   In this case, the support portion may have a mounting surface which is located outside the support surface and is substantially parallel to the support surface, the massaging portion may include a rear air bag which is mounted to the mounting surface in such a manner that one end portion thereof which is expandable in a bellows-like manner is distant from the support surface and an opposite end thereof which is unexpandable is closer to the support surface, the rear air bag being configured to expand in a fan-shaped form from a substantially flat state by inflowing air thereto, a receiver plate positioned in front of the rear air bag and mounted to a region of the support portion between the support surface and a mounting position of the rear air bag, the receiver plate being configured to be pivotable around a pivot extending substantially vertically; and a front air bag which is positioned in front of the receiver plate in such a manner that one end portion thereof which is expandable in a bellows-like manner is distant from the pivot and an opposite end thereof which is unexpandable is closer to the pivot, the front air bag being configured to expand in a fan-shaped form from a substantially flat state by inflowing air thereto. 
   In this case, preferably, the support portion may be configured in such a manner that the mounting surface is lower than the support surface to form a step between the mounting surface and the support surface. 
   In the above invention, preferably, the massaging portion may be configured to be controlled to operate in such a manner that the front air bag repeats expansion and contraction with the rear air bag expanded. 
   In the above invention, the massaging portion may further include a convex massaging element that is mounted in front of the front air bag and configured to press the lower leg of the user in contact with the lower leg of the user. 
   In the above invention, preferably, the receiver plate may be configured such that an outer end portion thereof is curved forward. 
   In the above invention, preferably, the support portion may have two support surfaces arranged rightward and leftward and configured to allow the right and left lower legs of the user to be supported thereon, and an intermediate mounting surface which is located between the two support surfaces and is substantially parallel to the support surface, and the massaging apparatus may further comprise an intermediate massaging portion that is mounted to the intermediate mounting surface and is configured to contract to form a substantially flat surface with the support surface and to expand to protrude forward further than the support surface. 
   In this case, the support portion may be configured in such a manner that the intermediate mounting surface is lower than the support surface to form a step between the intermediate mounting surface and the support surface. 
   In the above case, the intermediate air bag may be configured to have a width that increases in a downward direction. 
   In the above invention, preferably, the support portion may have two support surfaces arranged rightward and leftward and configured to allow the right and left lower legs of the user to be supported thereon, and an intermediate mounting surface that is located between the two support surfaces and is substantially parallel to the support surface, and the massaging apparatus may further comprise an intermediate massaging portion including one or a plurality of pairs of intermediate air bags that are mounted to the intermediate mounting surface in such a manner that corresponding first ends of the intermediate air bags, which are expandable in a bellows-like manner, are positioned closer to each other, and opposite ends of the intermediate air bags, which are unexpandable, are positioned distant from each other, the air bags being each configured to expand in a fan-shaped form from a substantially flat state by inflowing air thereto. 
   In this case, preferably, the one or the plurality of pairs of the intermediate air bags of the intermediate massaging portion may be mounted to the intermediate mounting surface in such a manner that a distance between the air bags forming the pair increases in a downward direction. 
   In the above invention, preferably, the massaging portion and the intermediate massaging portion may be configured to be controlled to operate in such a manner that the front air bag and the intermediate air bag repeat expansion and contraction in synchronization with each other. 
   In the above invention, preferably, the massaging portion and the intermediate massaging portion may be configured to be controlled to operate in such a manner that the rear air bag expands, then the front air bag and the intermediate air bag respectively expand in synchronization with each other, and then the rear air bag contracts while maintaining expansion of the front air bag and the intermediate air bag. 
   In the above invention, preferably, the support portion may include an upper support portion and a lower support portion which are arranged in a vertical direction, the massaging portion may be mounted to each of the upper support portion and the lower support portion, and the leg rest may further include a distance changing device configured to change a distance between the upper support portion and the lower support portion. 
   In the above invention, preferably, the support portion may have two support surfaces arranged rightward and leftward and configured to allow fight and lower legs of the user to be supported thereon, and a support protrusion mounted between the support surfaces to protrude forward further than the support surfaces and configured to support inner regions of calves of legs of the user, the expandable portion may include a massaging portion configured to press the lower leg of the user. 
   Further, the massaging portion may include an air bag configured to expand and contract by inflow and outflow air, and the air bag in a contracted state and the support surface may form a substantially flat surface, while the air bag in an expanded state is configured to press an outer region of a shin of the lower leg of the user substantially backward. 
   In such a construction, since the front side of the leg rest is shaped such that the support protrusion protrudes from an intermediate region in the width direction of the substantially flat surface with the air bags contracted, the user may assume a desired posture in a seated state without restriction of the legs. In addition, the user has only to find the position at which the inner region of the calf of the leg of the user contacts the support protrusion to enable to lower leg of the user to be guided to a proper massage position. Furthermore, the massaging portion is capable of massaging the outer region of the shin of the lower leg of the user. 
   In this case, preferably, the support protrusion may be configured to have a width that increases in a downward direction. 
   In the above case, preferably, the massaging portion may include massaging portions that are mounted at both end portions of the support portion so as to correspond to the fight and left lower legs of the user. 
   In this case, preferably, the support portion may have mounting surfaces positioned outside the support surfaces to be substantially parallel to the support surface, the massaging portion may include a rear air bag which is mounted to the mounting surface in such a manner that one end portion thereof which is expandable in a bellows-like manner is distant from the support surface and an opposite end thereof which is unexpandable is closer to the support surface, the rear air bag being configured to expand in a fan-shaped form from a substantially flat surface by inflowing air thereto, a receiver plate that is positioned in front of the rear air bag and mounted to a region of the support portion between the support surface and a mounting position of the rear air bag, the receiver plate being configured to be pivotable around a pivot extending substantially vertically; and a front air bag which is positioned in front of the receiver plate in such a manner that one end thereof which is expandable in a bellows-like manner is distant from the pivot and an opposite end thereof which is unexpandable is closer to the pivot, the front air bag being configured to expand in a fan-shaped form from a substantially flat state by inflowing air thereto. 
   In this case, preferably, the support portion may be configured in such a manner that the mounting surface is lower than the support surface to form a step between the mounting surface and the support surface. 
   In the above invention, preferably, the massaging portion may be configured to be controlled to operate in such a manner that the front air bag repeats expansion and contraction with the rear air bag expanded. 
   In the above invention, preferably, the massaging portion may further include a convex massaging element that is mounted in front of the front air bag and configured to contact and press the lower leg of the user. 
   In the above invention, preferably, the receiver plate may be configured such that an outer end portion thereof is curved forward. 
   In the above invention, preferably, the support portion may include an upper support portion and a lower support portion which are arranged in a vertical direction, the massaging portion may be mounted to each of the upper support portion and the lower support portion, and the leg rest may further include a distance changing device configured to change a distance between the upper support portion and the lower support portion. 
   In order to achieve the above object, a cover of the present invention for a massaging apparatus including a support surface on which a body of a user is supported and a protrusible and retractable system configured to protrude and retract with respect to the body within the support surface, the cover being configured to cover the support surface, comprises a foldable portion configured to expand according to the protrusion of the protrusible and retractable system and to be folded according to the retraction of the protrusible and retractable system. Since the cover is expandable and foldable according to the protruding and retracting operations within the support surface on which the body of the user is supported, it may be employed as the cover that covers the support surface. Because of the presence of the foldable portion, the cover need not be made of an elastic material. If the cover is made of the elastic material, its elasticity decreases. As a result, external appearance of the cover is maintained. 
   A cover of the present invention is a cover for a massaging apparatus including a protrusible and retractable system configured to protrude and retract, comprising a foldable portion configured to expand according to the protrusion of the protrusible and retractable system and to be folded to be substantially parallel to a cover surface according to the retraction of the protrusible and retractable system. In this construction, the foldable portion is configured for the protruding and retracting operations, and as a result, the external appearance is maintained as described above. Since the foldable portion is foldable to be substantially parallel to the cover surface, the protruding amount of the foldable portion is minimized. Thereby, when a cover is used to cover the support surface on which the body is supported, the foldable portion does not substantially disturb the user. As a result, the external appearance is improved. 
   In the cover that covers the support surface on which the body of the user is supported, preferably, the support surface may be substantially flat in retraction of the protrusible and retractable system, and the foldable portion may be configured to be folded to be substantially parallel to a cover surface in retraction. In this construction, since the foldable portion is folded to be substantially parallel to the cover surface, it does not substantially degrade the flatness of the support surface. As a result, the external appearance of the cover is improved, and the cover does not substantially disturb the body of the user. 
   Preferably, the foldable portion may have a plurality of coupled portions formed by coupling cover elements superimposed in a folded state to be substantially parallel to the cover surface in a thickness direction thereof in regions in the vicinity of the coupled portions. In this construction, the foldable portion is not merely folded but the superimposed cover elements are coupled in the thickness direction. The coupled state causes a restricting force, allowing the foldable portion that has expanded according to the protrusion of the protrusible and retractable system to return to its folded state of retraction of the protrusible and retractable system. 
   Preferably, the foldable portion may be configured such that expansion at an end portion in a direction of a line formed by the coupled portion is restricted. In this construction, since the restricting force for causing the foldable portion to return to its folded state is generated by the restriction in the foldable portion that has expanded by the protrusion of the protrusible and retractable system, the foldable portion easily returns to its folded state during the retraction. 
   A cover of the present invention for a leg rest including a support surface on which right and left legs are supported, and a protrusible and retractable system configured to protrude and retract with respect to the legs within the support surface, comprises an expandable and contractable portion which is positioned on an intermediate region in a rightward and leftward direction of the support surface and configured to expand and contract according to protrusion and retraction of the protrusible and retractable system. Since the cover has the expandable and contractable portion capable of expanding and retracting according to the protruding and retracting operations at the intermediate regions in the rightward and leftward direction of the support surface, it is employed as the cover that covers the leg rest. Since the expandable and contractable portion contracts during retraction of the protrusible and retractable system, the cover does not substantially interfere with the system during the retraction. Since the protrusible and retractable system is positioned at the intermediate region in the rightward and leftward direction of the support surface of the leg rest so that the system is protrusible between the right and left legs, the legs are suitably massaged. 
   In the cover for a leg rest, preferably, the protrusible and retractable system provided in the leg rest may be configured such that the support surface is substantially flat when the system is in retraction. 
   Further, the expandable and contractable portion may be a foldable portion configured to expand according to protrusion of the protrusible and retractable system and to be folded to be substantially parallel to the cover surface by retraction of the protrusible and retractable system. In this construction, since the expandable and contractable portion is the foldable portion which is foldable to be substantially parallel to the cover surface, the cover does not substantially reduce the flatness of the support surface, which is substantially flat in retraction. As a result, the expandable and contractable portion does not substantially disturb the user, and the external appearance of the cover is improved. 
   A massaging apparatus of the present invention comprises a support surface on which a body of a user is supported; a protrusible and retractable system configured to protrude and retract with respect to the body within the support surface; and a cover configured to cover the support surface and to include a foldable portion configured to expand by protrusion of the protrusible and retractable system and to be folded by retraction of the protrusible and retractable system. In this construction, since the cover is capable of covering the support surface on which the body of the user is supported and the protrusible and retractable system is mounted. Furthermore, since the cover is provided with a foldable portion that is expandable and foldable by the protruding and retracting operations, the external appearance of the massaging apparatus is maintained. 
   The above and further objects and features of the invention will more fully be apparent from the following detailed description and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a chair-type massaging apparatus according to a first embodiment of the present invention; 
       FIG. 2  is a front view of a leg rest of the chair-type massaging apparatus of  FIG. 1 ; 
       FIG. 3  is a plan view of the leg rest of  FIG. 2 , showing a state in which air cells (air bags) contract; 
       FIG. 4  is a plan view of the leg rest of  FIG. 2 , showing a state in which the air cells expand; 
       FIG. 5  is a cross-sectional view of a lower air cell in a contracted state; 
       FIG. 6  is a cross-sectional view of the lower air cell in an expanded state; 
       FIG. 7  is a front view of a leg rest according to a second embodiment of the present invention; 
       FIG. 8  is a plan view of the leg rest of  FIG. 7 , showing a state in which air cells contract; 
       FIG. 9  is a plan view of the leg rest of  FIG. 7 , showing a state in which the air cells expand; 
       FIG. 10  is a plan view of a leg rest according to a third embodiment of the present invention, showing a state in which the air cells contract; 
       FIG. 11  is a plan view of the leg rest according to the third embodiment of the present invention, showing a state in which the air cells expand; 
       FIG. 12  is a perspective view showing a construction of an entire chair-type massaging apparatus according to a fourth embodiment of the present invention; 
       FIG. 13  is an exploded perspective view showing a construction of a massaging system included in the chair-type massaging apparatus according to the fourth embodiment of the present invention; 
       FIG. 14  is a front view showing a construction of a leg rest included in the chair-type massaging apparatus according to the fourth embodiment of the present invention; 
       FIG. 15  is a plan view showing a construction of the leg rest included in the chair-type massaging apparatus according to the fourth embodiment of the present invention; 
       FIG. 16  is a plan view showing a construction of the leg rest included in the chair-type massaging apparatus according to the fourth embodiment of the present invention; 
       FIG. 17  is a plan cross-sectional view showing a construction of a rear air cell in a contracted state; 
       FIG. 18  is a plan cross-sectional view showing a construction of the rear air cell in an expanded state; 
       FIG. 19  is a partially enlarged plan view showing a hinge structure of a receiver plate according to the fourth embodiment of the present invention; 
       FIG. 20  is a side view showing a rotating structure of the leg rest according to the fourth embodiment of the present invention; 
       FIG. 21  is a block diagram showing a part of a configuration of the chair-type massaging apparatus according to the fourth embodiment of the present invention; 
       FIG. 22  is a flowchart showing an example of an operation control of the leg rest included in the chair-type massaging apparatus according to the fourth embodiment of the present invention; 
       FIG. 23  is a perspective view showing a construction of an entire chair-type massaging apparatus according to a fifth embodiment of the present invention; 
       FIG. 24  is a front view showing a construction of a leg rest included in the chair-type massaging apparatus according to the fifth embodiment of the present invention; 
       FIG. 25  is a plan view showing a construction of the leg rest included in the chair-type massaging apparatus according to the fifth embodiment of the present invention; 
       FIG. 26  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the fifth embodiment of the present invention; 
       FIG. 27  is a block diagram showing a part of a configuration of the chair-type massaging apparatus according to the fifth embodiment of the present invention; 
       FIG. 28  is a flowchart showing an example of an operation control of the leg rest included in the chair-type massaging apparatus according to the fifth embodiment of the present invention; 
       FIG. 29  is a perspective view showing a construction of an entire chair-type massaging apparatus according to a sixth embodiment of the present invention; 
       FIG. 30  is a front view showing a construction of a leg rest included in the chair-type massaging apparatus according to the sixth embodiment of the present invention; 
       FIG. 31  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the sixth embodiment of the present invention; 
       FIG. 32  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the sixth embodiment of the present invention; 
       FIG. 33  is a block diagram showing a part of a configuration of the chair-type massaging apparatus according to the sixth embodiment of the present invention; 
       FIG. 34  is a flowchart showing an example of an operation control of the leg rest included in the chair-type massaging apparatus according to the sixth embodiment of the present invention; 
       FIG. 35  is a front view showing a construction of a leg rest included in the chair-type massaging apparatus according to a seventh embodiment of the present invention; 
       FIG. 36  is a plan view showing a construction of the leg rest included in the chair-type massaging apparatus according to the seventh embodiment of the present invention; 
       FIG. 37  is a plan view showing a construction of the leg rest included in the chair-type massaging apparatus according to the seventh embodiment of the present invention; 
       FIG. 38  is a partially enlarged plan view of the leg rest of  FIG. 37 ; 
       FIG. 39  is a front view showing a construction of an example of the leg rest included in a chair-type massaging apparatus according to an eighth embodiment of the present invention; 
       FIG. 40  is a plan view showing the construction of the example of the leg rest included in the chair-type massaging apparatus according to the eighth embodiment of the present invention; 
       FIG. 41  is a plan view showing the construction of the example of the leg rest included in the chair-type massaging apparatus according to the eighth embodiment of the present invention; 
       FIG. 42  is a front view showing the construction of another example of the leg rest included in the chair-type massaging apparatus according to the eighth embodiment of the present invention; 
       FIG. 43  is a plan view showing the construction of another example of the leg rest included in the chair-type massaging apparatus according to the eighth embodiment of the present invention; 
       FIG. 44  is a plan view showing the construction of another example of the leg rest included in the chair-type massaging apparatus according to the eighth embodiment of the present invention; 
       FIG. 45  is a front view showing a construction of a leg rest included in a chair-type massaging apparatus according to a ninth embodiment of the present invention; 
       FIG. 46  is a side view showing the construction of the leg rest included in a chair-type massaging apparatus according to the ninth embodiment of the present invention; 
       FIG. 47  is a front view showing a construction of the leg rest with air cells in an expanded state according to the ninth embodiment of the present invention; 
       FIG. 48  is a side view showing a construction of the leg rest with the air cells in an expanded state according to the ninth embodiment of the present invention; 
       FIG. 49  is a perspective view showing a construction of a leg rest of a chair-type massaging apparatus according to a tenth embodiment of the present invention; 
       FIG. 50  is a perspective view showing a construction of an expandable and contractable system of the leg rest according to the tenth embodiment of the present invention; 
       FIG. 51  is a perspective view showing the construction of the expandable and contractable system of the leg rest according to the tenth embodiment of the present invention; 
       FIG. 52  is a perspective view showing the construction of the expandable and contractable system of the leg rest according to the tenth embodiment of the present invention; 
       FIG. 53  is a perspective view showing the construction of the expandable and contractable system of the leg rest according to the tenth embodiment of the present invention; 
       FIG. 54  is a perspective view showing a construction of an entire chair-type massaging apparatus according to an eleventh embodiment of the present invention; 
       FIG. 55  is a front view showing a construction of a leg rest included in the chair-type massaging apparatus according to the eleventh embodiment of the present invention; 
       FIG. 56  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the eleventh embodiment of the present invention; 
       FIG. 57  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the eleventh embodiment of the present invention; 
       FIG. 58  is a front view showing a construction of a leg rest included in a chair-type massaging apparatus according to a twelfth embodiment of the present invention; 
       FIG. 59  is a plan view showing a construction of the leg rest included in the chair-type massaging apparatus according to the twelfth embodiment of the present invention; 
       FIG. 60  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the twelfth embodiment of the present invention; 
       FIG. 61  is a partially enlarged plan view of the leg rest of  FIG. 60 ; 
       FIG. 62  is a front view showing a construction of a leg rest included in a chair-type massaging apparatus according to a thirteenth embodiment of the present invention; 
       FIG. 63  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the thirteenth embodiment of the present invention; 
       FIG. 64  is a plan view showing the construction of the leg rest included in the chair-type massaging apparatus according to the thirteenth embodiment of the present invention; 
       FIG. 65  is a front view showing a construction of a leg rest included in a chair-type massaging apparatus according to a fourteenth embodiment of the present invention; 
       FIG. 66  is a side view showing the construction of the leg rest included in the chair-type massaging apparatus according to the fourteenth embodiment of the present invention; 
       FIG. 67  is a front view showing a construction of the leg rest with the air cells in an expanded state according to the fourteenth embodiment of the present invention; 
       FIG. 68  is a side view showing a construction of the leg rest with the air cells in an expanded state according to the ninth embodiment of the present invention; 
       FIG. 69  is a perspective view showing a construction of a leg rest included in a chair-type massaging apparatus according to a fifteenth embodiment of the present invention; 
       FIG. 70  is a perspective view of a chair-type massaging apparatus with a cover according to a sixteenth embodiment of the present invention attached thereto; 
       FIG. 71  is a cross-sectional view showing a state in which the cover of the sixteenth embodiment of the present invention covers a leg massaging system; 
       FIG. 72(   a ) is an enlarged cross-sectional view of a foldable portion of the cover according to the sixteenth embodiment of the present invention and  FIG. 72(   b ) is an enlarged cross-sectional view of an alternative; 
       FIG. 73(   a ) is a view showing an external appearance of a state in which a foldable portion of the cover of the sixteenth embodiment is folded, and  FIG. 73(   b ) is a view showing an external appearance of an expanded state of the foldable portion; 
       FIG. 74  is an enlarged cross-sectional view of a bellows-like foldable portion; 
       FIG. 75  is a cross-sectional view showing a state in which a cover according to a seventeenth embodiment of the present invention covers the leg massaging system; 
       FIG. 76  is an enlarged cross-sectional view of an intermediate foldable portion in the cover according to the seventeenth embodiment of the present invention; 
       FIG. 77  is an enlarged cross-sectional view of an alternative of a foldable portion; 
       FIG. 78  is a front view of the leg massaging system; 
       FIG. 79  is a plan view of the leg massaging system in a retracted state; 
       FIG. 80  is a plan view of the leg massaging system in a protruded state; 
       FIG. 81  is a view showing how an intermediate foldable portion expands; 
       FIG. 82  is a view showing how a right or left foldable portion expands; and 
       FIG. 83  is a view showing how an alternative of the right or left foldable portion expands. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, embodiments of the present invention will be described with reference to the drawings. 
   Embodiment 1 
     FIG. 1  is a perspective view of a chair-type massaging apparatus  1  according to a first embodiment of the present invention. The chair-type massaging apparatus  1  comprises a seat portion  2 , a back rest  3 , a leg rest  4  and arm rests  5 . The leg rest  4  is attached to a front portion of the seat portion  2  and is rotatable around an axis located at and extending along an upper end of the leg rest  4 . Thereby, the leg rest  4  is attached at a variable angle to the seat portion  2  and is configured for change in a bending angle of a leg of a user seated therein. The back rest  3 , the seat portion  2 , and the arm rest  5  may be provided with massaging elements that massage body parts of the user, although not shown. While the leg rest  4  is covered with a cover made of a cloth or the like, the cover covering the leg rest  4  is omitted in  FIG. 1 . 
     FIG. 2  is a front view of the leg rest  4 .  FIGS. 3 and 4  are plan views of the leg rest  4 .  FIG. 3  shows a state in which air cells (air bags) described later contract and  FIG. 4  shows a state in which the air cells expand. The leg rest  4  includes a support portion  7  having support surfaces  6  on which lower legs of the user are supported. The leg rest  4  is symmetric in structure in the rightward and leftward direction and is capable of uniformly massaging right and left lower legs of the user. 
   As used herein, the terms “rightward and leftward direction” and “forward and backward direction” mean directions from the perspective of the user seated in the chair-type massaging apparatus  1 , and “vertical direction” means the direction perpendicular to the “rightward and leftward direction” on a plane parallel to the support surfaces  6 . 
   The support portion  7  has a substantially flat base  16  (see  FIG. 3 ), and protrusible portions  9  which are protrusible to rise up inward in the right and leftward direction and are retractable. Each protrusible portion  9  includes a receiver plate  13  which is constructed of a plate element of a substantially rectangular shape which is elongate in the vertical direction of the leg rest  4 . Each receiver plate  13  is mounted at an inner peripheral region thereof in the rightward and leftward direction to the base  16  (see  FIG. 3 ) of the support portion  7  by a hinge  20 . A torsion spring  21  is mounted to the hinge  20  and is configured to bias the receiver plate  13  outward in the rightward and leftward direction (in the direction to retract the receiver plate  13 ). A rotational axis Z 1  of each hinge  20  is mounted to be oriented vertically. Each lower cell  14  is provided between the receiver plate  13  and the base  16  on the rear surface side of the receiver plate  13 . 
   A massaging plate  10 , which serves as a massaging element  8 , is mounted on each receiver plate  13 . As shown in  FIGS. 1 and 2 , each massaging plate  10  is comprised of an upper massaging plate  11  and a lower massaging plate  12 . As shown in  FIGS. 2 and 3 , the upper massaging plate  11  and the lower massaging plate  12  are mounted at inner peripheral regions thereof to the receiver plate  13  by the hinges  20 . A rotational axis Z 2  of each hinge  20  is oriented vertically as in the rotational axes Z 1 . The torsion spring  21  is mounted to each hinge  20  and is configured to bias each of the upper massaging plate  11  and the lower massaging plate  12  outward in the rightward and leftward direction (in the direction to retract these plates  11  and  12 ). 
   Air cells  17  are each provided between the upper massaging plate  11  and the lower massaging plate  12 , and the receiver plate  13  on the rear surface side of the upper massaging plate  11  and the lower massaging plate  12 . Each air cell  17  is divided in two in the vertical direction, as is each massaging plate  10 . Each air cell  17  includes an upper massaging air cell  18  located between the upper massaging plate  11  and the receiver plate  13  and a lower massaging air cell  19  located between the lower massaging plate  12  and the receiver plate  13 . It shall be appreciated that, in  FIG. 2 , contours of the upper massaging air cell  18  and the lower massaging air cell  19  overlap with contours of the upper massaging plate  11  and the lower massaging plate  12 . 
   Pressing elements  26  are mounted at appropriate positions on the upper massaging plate  11  and the lower massaging plate  12  and are configured to have convex curved surfaces protruding toward the user. In this manner, the massaging portion  8  and the protrusible portion  9  form an expandable portion of the present invention. 
   Now, protruding and retracting operation of the massaging plate  10  and the receiver plate  13  will be described. 
   The above mentioned air cells (lower air cell  14 , upper massaging air cell  18 , and lower massaging air cell  19 ) and an intermediate air cell  23  described later are connected to an air inflow and outflow device (not shown) through air hoses or the like, and are capable of repeated expansion and contraction by air inflow and outflow by the air inflow and outflow device. 
   As shown in  FIG. 4 , when the lower air cell  14  expands, the receiver plate  13  is pushed by the lower air cell  14  from its rear surface side and protrudes to rise up inward in the rightward and leftward direction. Conversely, when the lower air cell  14  contracts, the receiver plate  13  retracts outward in the rightward and leftward direction by a bias force applied from the torsion spring  21 . 
   When the air cells  17 , including the upper massaging air cell  18  and the lower massaging air cell  19 , expand, the massaging plate  10  (including upper massaging plate  11  and the lower massaging plate  12 ) is pushed from the side of its rear surface side by the air cell  17 , causing the upper massaging plate  11  and the lower massaging plate  12  to collapse inward in the rightward and leftward direction (toward the lower leg  22  of the user). Conversely, when the air cell  17  contracts, the upper massaging plate  11  and the lower massaging plate  12  retract outward in the rightward and leftward direction by the bias force applied from the torsion spring  21 . Since the upper massaging air cell  18  and the lower massaging air cell  19  are capable of expansion and contraction independently of each other, the upper massaging plate  11  and the lower massaging plate  12 , which are pushed by the air cells, are capable of protrusion and retraction (rotation) independently of each other. 
   Two intermediate air cells  23 , which serve as intermediate massaging portions  15 , are mounted at an intermediate region in the rightward and leftward direction of the support portion  7  and are located to be symmetric in the rightward and leftward direction with respect to a center line  25  (imaginary broken line in  FIG. 2 ) of the support portion  7 . As shown in  FIG. 4 , when the intermediate air cell  23  expands to push the lower leg  22  from inward, the lower leg  22  is sandwiched between the intermediate air cell  23  and the massaging plate  10  (or pressing element  26 ). 
   In this manner, when all of the air cells included in the leg rest  4 , i.e., air cells  14 ,  18 ,  19 , and  23 , expand and contract, the massaging plate  10 , the receiver plate  13 , and the intermediate air cell  23 , which serves as the intermediate massaging portion  15 , protrude and retract. When all the air cells contract to cause the massaging plate  10 , the receiver plate  13 , and the intermediate massaging portion  15  to retract, the receiver plate  13 , the elements of the support portion  7  which are located inward of the receiver plate  13  and include the intermediate air cell  23 , and the massaging plate  10  form a substantially flat surface. Furthermore, the front surface of the leg rest  4  is substantially flat (see  FIG. 3 ). 
   Here, a structure of each air cell will be described in detail.  FIG. 5  is a cross-sectional view of the lower air cell  14  in a contracted state and  FIG. 6  is a cross-sectional view of the lower air cell  14  in an expanded state. The other cells (upper massaging air cell  18 , lower massaging air cell  19 , and intermediate air cell  23 ) have structures similar to that of the lower air cell  14  and will not be further described. 
   As shown in  FIG. 6 , the lower cell  14  is comprised of a plurality of (in this embodiment, three) air bags, and air spaces of the plurality of air bags communicate with each other through a through hole  14   a  to permit air communication between them. The plurality of air bags are coupled at one end side  14   b  of the lower air cell  14  so as not to expand. On the other hand, the air bags are not coupled at an opposite end side  14   c  and are therefore capable of expanding. With such a structure, when air is inflowed from the air inflow and outflow device (not shown) and flows into the lower air cell  14  through an air inlet  14   d , the air flows through the through hole  14   a  and fills all the air bags, causing the lower cell  14  to expand (see  FIG. 6 ). Since the air bags are configured not to expand at one end  14   b  and to be able to expand at the opposite end  14   c , the opposite end  14   c  expands in a bellows-like manner, and thus, the lower air cell  14  expands in a substantially fan-shaped form in cross-section, as shown in  FIG. 6 . An end portion of the one end side  14   b  configured not to expand becomes a center  14   z  of a fan-shaped form of the substantially fan-shaped form in cross-section. 
   The air inlet  14   d  is desirably provided at a position which is not displaceable after the expansion and contraction (only at a bottom portion  14   e  which is located lowermost in the lower cell  14  of this embodiment). In this structure, the air inlet  14   d  does not limit the expansion of the lower air cell  14 . 
   Thus, in the leg rest  4  of this embodiment, all the air cells  14 ,  18 ,  19  and  23  are capable of expanding in the substantially fan-shaped form in cross-section. Furthermore, placement of these air cells is devised. 
   The lower cell  14  is placed such that the center  14   z  is positioned inward in the rightward and leftward direction of the support portion  7  (see  FIGS. 3 and 4 ). The center  14   z , which is an expansion axis of the lower air cell  14 , extends vertically. In this structure, since the center  14   z  of the lower air cell  14  and the first rotational axis Z 1  which is a rotational axis of the receiver plate  13  which is pushed by the lower air cell  14  to rotate and is placed inward in the rightward and leftward direction of the receiver plate  13  (identical to a rotational axis of the hinge  20  mounted to the receiver plate  13 ) are disposed close to each other on the same side in the rightward and leftward direction, the lower air cell  14  and the receiver plate  13  are greatly movable at outward regions in the rightward and leftward direction (see  FIG. 4 ). As a result, the receiver plate  13  rotates very efficiently by the expansion and contraction of the lower cell  14 . 
   The same relationship is established between the massaging plate  10  and the air cells  17  (upper massaging air cell  18  and lower massaging air cell  19 ). 
   Each of the upper massaging air cell  18  and lower massaging air cell  19  is placed such that a center  18 Z,  19 Z of the fan-shaped form is positioned inward in the rightward and leftward direction of the support portion  7  when the upper massaging air cell  18  and lower massaging air cell  19  are in the contracted position (see  FIGS. 3 and 4 ). The center  18 Z,  19 Z, which is a respective expansion axis of the upper massaging air cell  18  and lower massaging air cell  19 , extends vertically. Thereby, since the respective centers  18 Z,  19 Z of the upper massaging air cell  18  and lower massaging air cell  19  and a second rotational axis Z 2 , which is a rotational axis (rotational axis of the hinge  20  mounted to the massaging plate  10 ) of the massaging plate  10  (including upper massaging plate  11  and the lower massaging plate  12 ) which is pushed by the upper massaging air cell  18  and lower massaging air cell  19  to rotate, are disposed close to each other on respective same sides in the rightward and leftward direction, the upper massaging air cell  18  and lower massaging air cell  19  are greatly movable at outward regions in the rightward and leftward direction. As a result, the massaging plate  10  (including upper massaging plate  11  and lower massaging plate  12 ) rotate very efficiently by the expansion and contraction of the upper massaging air cell  18  and lower massaging air cell  19 . 
   It shall be understood that the first rotational axis Z 1  and the second rotational axis Z 2  are not shafts forming the respective shafts Z 1  and Z 2 , but are imaginary axes which are the centers of rotation. Therefore, elements including the rotational axes Z 1  and Z 2  are meant to include elements which do not form shafts but have imaginary axes which become rotational centers, for example, thin hinges, as well as the hinges  20  having shafts. 
   In the above construction, the structure of the massaging portion  8  or the protrusible portion  9  becomes very simple. As a result, the chair-type massaging apparatus (especially leg rest  4 ) becomes small-sized and lightweight, and a manufacturing costs and component costs are reduced. 
   The intermediate air cells  23  which serve as the intermediate massaging portions are placed as described below. As described previously, the intermediate air cells  23  are provided on right and left sides to be symmetric in the rightward and leftward direction with respect to a center line  25  in the rightward and leftward direction (see  FIG. 2 ). The right and left intermediate air cells  23  are placed such that their centers  23 Z of fan-shaped form are positioned outward in the rightward and leftward direction (see  FIGS. 3 and 4 ). The center axes  23 Z which are expansion axes of the intermediate air cells  23  extend vertically. As shown in  FIG. 4 , since the right and left intermediate air cells  23  expand toward the right and left lower legs  22  of the user, the intermediate massaging portions  15  are able to efficiently press the right and left lower legs  22  from inward in the rightward and leftward direction. Since each lower leg  22  is sandwiched and massaged by the corresponding intermediate air cell  23  and massaging plate  10  (including upper massaging plate  11  and lower massaging plate  12 ), it is reliably and strongly pressed or massaged. 
   The chair-type massaging apparatus  1  of this embodiment constructed as described above makes it possible that the lower legs  22  are massaged with the user seated therein. In addition, when the massaging portion  8 , the protrusible portion  9 , and the intermediate massaging portion  15  retract, the protrusible portion  9 , the elements of the support portion  7  which are located inward of the protrusible portion  9  in the rightward and leftward direction, and the massaging portion  8  form a substantially flat surface, so that the user can assume a posture freely without any interference. Furthermore, the chair-type massaging apparatus  1  has a relatively simple design and improves its external appearance. 
   The protrusible portions  9  are located on both sides in the rightward and leftward direction. The protrusible portions  9  protrude to rise up inward in the rightward and leftward direction, while they retract leftwardly and rightwardly. Therefore, in a retracted state of the protrusible portion  9 , the lower leg  22  is not disturbed by the protrusible portion  9  and the support portion  7  located inward of the protrusible portion  9 . 
   Since the massaging plate  10  is mounted on the protrusible portion  9  configured to protrude to rise up inward in the rightward and leftward direction and is configured to protrude and retract, a pressing angle or pressing position of the massaging portion  8  with respect to the lower leg  22  are set quite freely. By combining the rising angle of the protrusible portion  9  and the position or protruding angle of the massaging plate  10  in various ways, the pressing angle or the pressing position with respect to the lower leg  22  are set quite freely. Since the massaging plate  10  is not installed on a flexible air cell but on the receiver plate  13  of the protrusible portion  9  which is a part of the support portion  7 , the massaging portion  8  is installed on a rigid base. As a result, positional or angular displacement of the massaging plate  10  is minimized, and the pressing angle or the pressing position, and the pressing force are set with high precision. 
   It is essential that the chair-type massaging apparatus massage the user suitably. Regarding a massager that massages the lower leg  22  of the user, it is essential that the pressing position, the pressing angle and the pressing force with respect to the lower leg  22  of the user be set optimally and accurately. The improvement of setting freedom and precision in the massaging apparatus enhances performance of the massaging apparatus. 
   As shown in  FIG. 4 , in this embodiment, the lower leg  22  is pressed from substantially forward toward rearward. The pressing position and the pressing angle of the massaging plate  10  (or pressing element  26 ) with respect to the lower leg  22  are finely adjustable by appropriately setting the position or angle of the massaging plate  10  provided on the receiver plate  13  rotating. For example, the pressing position is easily adjusted so that the lower leg  22  is pressed at plural acupuncture points thereof. 
   When the massaging portion  8  includes the rotatable massaging plate  10  and the protrusible portion  9  includes the rotatable receiver plate  13  as illustrated in this embodiment, a very simple structure is provided. In this embodiment, the first rotational axis Z 1  which is the rotational axis of the receiver plate  13  and the second rotational axis Z 2  which is the rotational axis of the massaging plate  10  are provided at different positions. To be specific, the first rotational axis Z 1  and the second rotational axis Z 2  extend vertically of the leg rest  4  substantially in parallel, and the second rotational axis Z 2  is positioned outward of the first rotational axis Z 1  in the rightward and leftward direction when the receiver plate  13  and massaging plate are in the retracted positions, respectively. 
   In contrast to the configuration in which the position of the first rotational axis Z 1  coincides with that the second rotational axis Z 2 , the pressing angle and the pressing position of the massaging plate  10  with respect to the lower leg  22  are set quite freely. 
   While the leg rest  4  of the first embodiment is constructed such that the massaging plate  10  is comprised of the upper massaging plate  11  and the lower massaging plate  12 , it may alternatively be divided into right and left parts or otherwise three or more parts. In a further alternative, the receiver plate  13  may be suitably divided. The massaging plate  10  and the receiver plate  13  may be thus divided and the air cells that push these plates may be placed at separate positions so as to correspond to these divided plates. Thereby, since the divided plates may independently protrude and retract, a variety of massaging patterns are created. 
   As shown in  FIG. 3 , the base  16  of the support portion  7  of the first embodiment is constructed such that the support surface  6  is set higher. In other words, the right and left sides outside the support surface  6  are set lower. For this reason, when the protrusible portion  9  (receiver plate  13 ) and the massaging portion  8  (massaging plate  10 ) retract, at least part of the receiver plate  13  and the massaging plate  10  are accommodated in the lower region. This desirably improves the above mentioned flatness. Furthermore, the region in which the intermediate massaging portion  15  (intermediate air cell  23 ) is located lower than the support surface  6 , and at least part of the intermediate air cell  23  is accommodated in the lower region. Likewise, this desirably improves flatness. 
   Embodiment 2 
     FIGS. 7 to 9  are views showing the leg rest  4  mounted to the chair-type massaging apparatus according to a second embodiment of the present invention.  FIG. 7  is a front view of the leg rest  4 .  FIGS. 8 and 9  are plan views ( FIG. 8  shows a contracted state of air cells and  FIG. 9  shows an expanded state of the air cells). 
   In the second embodiment, one intermediate air cell  23 , which serves as the intermediate massaging portion  15 , is provided instead of two (two air cells on the right and left sides). The intermediate air cell  23  is configured not to expand in substantially fan-shaped form in cross-section, but to entirely expand forward substantially uniformly as shown in  FIGS. 8 and 9 . 
   As shown in  FIG. 7 , the intermediate air cell  23  is symmetric in the rightward and leftward direction with respect to an imaginary center line  25  in the rightward and leftward direction, and is shaped such that its width continuously decreases from its upper side to its lower side so as to well conform to the shape of the lower leg  22  whose thickness gradually decreases from its knee to its ankle. Thus, the intermediate massaging portion  15 , the protrusible portion  9  or the massaging portion  8  is placed to be tilted with respect to the vertical direction so that a spacing between the massaging portion  8  and the intermediate massaging portion  15  decreases toward the lower side of the support portion  7  while protruded. 
   In the second embodiment, the massaging plate  10  and the pressing element  26  are omitted and the massaging portion  8  is comprised of the upper massaging air cell  18  and the lower massaging air cell  19 . That is, the upper massaging air cell  18  (lower massaging air cell  19 ) presses the lower leg  22  without the massaging plate  10  and the pressing elements  26 . Such a construction may be, as a matter of course, applied to the present invention. 
   Embodiment 3 
     FIGS. 10 and 11  are plan views of the leg rest  4  according to a third embodiment of the present invention.  FIG. 10  shows a contracted state of the air cells and  FIG. 11  shows an expanded state of the air cells. In the third embodiment, the intermediate massaging portion  15  in the support portion  7  is omitted. In addition, differently from the first and second embodiments, the receiver plate  13  of the support portion  7  is not perfectly flat, and is bent α degrees forward in the vicinity of a substantially center position thereof in the rightward and leftward direction. The upper massaging air cell  18  and the lower massaging air cell  19  are provided as the massaging portion  8  to be positioned outward relative to the bent position in the rightward and leftward direction. In this construction, also, in the contracted state of the air cells, the protrusible portion  9 , the elements of the support portion  7  which are located inward of the protrusible portion  9  and the massaging portion  8  form a substantially flat surface. Therefore, the user is not obstructed and may be seated more freely. It shall be understood that if the angle α is too large, then the flatness decreases, and therefore the angle α is desirably 30 degrees or less. 
   Embodiment 4 
     FIG. 12  is a perspective view showing a construction of an entire chair-type massaging apparatus according to a fourth embodiment of the present invention. As shown in  FIG. 12 , a chair-type massaging apparatus  101  of this embodiment is chair-shaped and mainly comprises a seat portion  102 , a back rest  103 , a leg rest  104 , and arm rests  105 . The seat portion  102  is constructed such that a cushion portion  102   c  whose upper surface is substantially flat for use as a seat surface  102   b  is provided on a base (not shown) having leg portions  102   a  on both sides of its lower portion. The cushion portion  102   c  is formed in such a manner that an internal material (not shown) such as urethane foam, sponge, or foamed polystyrene is provided over the upper surface of the base and is covered with an outer material (cover) formed of a raised-fiber tricot made of polyester, artificial leather, or natural leather, etc. 
   To a front side of an upper portion of the seat portion  102  (front side when viewed from the perspective of the user seated in the chair-type massaging apparatus  101 , and right and left sides are viewed from the perspective of the user seated in the apparatus  101 ), the leg rest  104  is pivotally attached at an upper end thereof to massage the ankles and calves of the legs of the user. The leg rest  104  is pivotable forward and backward around the upper end thereof. 
   The leg rest  104  is entirely of a substantially flat-plate shape, and is configured to support the calves of the user on a front surface thereof. As described in detail later, the leg rest  104  is provided with a plurality of air cells (air bags) which are connected to an air inflow and outflow device  109  including a pump, a valve, and other components which are built in the seat portion  102  or the back rest  103  through air hoses  139  (see  FIG. 21 ). The air cells expand or contract by air inflow and outflow by the air inflow and outflow device  109 . With the user seated in the seat portion  102 , the air cells expand and contract repeatedly, thus applying pressing stimulation to the legs. 
   A plurality of air cells are further provided on a back side of the seat surface  102   b  of the seat portion  102 . These air cells are also connected to the air inflow and outflow device  109  through air hoses (not shown) and are configured to expand and contract by air inflow and outflow by the air inflow and outflow device  109 . A vibrator (not shown) which is identical to that described previously is provided on a back side of the center of the seat surface  102   b  of the seat portion  102 . With such a construction, the air cells expand and contract repeatedly to apply pressing stimulation to a hip of the user, and in this state, the vibrator is driven to apply vibration stimulation to an anus region of the user, with the user seated on the seat portion  102 . 
   The back rest  103  is provided on a rear portion of the seat portion  102 . The back rest  103  is sized so that an adult with a standard frame is seated on the chair-type massaging apparatus  101  so as not to protrude outward therefrom and is shaped to be substantially rectangular as viewed from front in order to support the upper half body of the user. The back rest  103  is pivotally mounted at a lower end portion thereof to the rear portion of the seat portion  102  by a horizontal pivot and is rotatable around the pivot to enable reclining forward and backward. The arm rests  105  are respectively provided on both sides of the back rest  103  and are fixedly supported on the base of the seat portion  102 . The arm rests  105  extend forward from the both sides of the back rest  103  and are used as arm rests with the user seated in the chair-type massaging apparatus  101 . 
   A massaging system  106  illustrated in  FIG. 13  is mounted inside the back rest  103 .  FIG. 13  is an exploded perspective view showing a construction of the massaging system  106  included in the chair-type massaging apparatus  101  according to this embodiment of the present invention. The massaging system  106  includes four roller-shaped massaging elements  110  that apply mechanical stimulation to the body of the user and motors  111  and  112  of DC servo motors that drive the massaging elements  110  to displace. The massaging elements  110  are respectively mounted to tip ends of V-shaped arms  113 . The arms  113  are respectively mounted to two substantially V-shaped connecting rods  114  to be rotatable within a predetermined range. Each connecting rod  114  is provided with a fitting hole  115 . Tilted portions  117  are provided on both ends of a rotational shaft  116  and are loosely fitted into the fitting holes  115 . The tilted portions  117  are tilted at a predetermined angle with respect to the rotational shaft  116 . A helical gear  118   a  is coaxially mounted on an intermediate region of the rotational shaft  116  and is in mesh with a worm screw  118   b . Thus, the helical gear  118   a  and the worm screw  118   b  form a worm gear system  118 . 
   A pulley  119   a  is coaxially mounted on one end of the worm screw  118   b . The pulley  119   a  is coupled to a pulley  119   c  mounted on an output shaft of the motor  111  through a belt  119   b . Therefore, the rotation of the motor  111  is transmitted to the worm screw  118   b  through the belt  119   b , causing the worm screw  118   b  to rotate. As a result, the rotational shaft  116  rotates. According to the rotation of the rotational shaft  116 , the tilted portions  117  are displaced to draw conical paths. Thereby, the connecting rods  114  operate in a predetermined manner, causing the right and left massaging elements  110  to move close to and away from each other so as to draw a substantially oval shape both in the rightward and leftward direction and in the vertical direction. This operation corresponds to a kneading operation. The kneading operation of the massaging elements  110  includes forward movement (toward the user) in which the right and left massaging elements  110  move close to each other and rearward movement in which the massaging elements  110  move away from each other. In this manner, in the kneading operation, the massaging elements  110  move three-dimensionally. 
   As shown in  FIG. 13 , each connecting rod  114  is provided with a fitting hole  120  on a lower region thereof. A protruding portion  122  provided on a coupling element  121  is inserted into the fitting hole  120 . The coupling element  121  is provided with a horizontal hole  123 . Eccentric portions  125  are provided on both ends of a rotational shaft  124  and are fitted into the holes  123 . A pulley  126   a  is coaxially mounted on an intermediate region of the rotational shaft  124  and is coupled to a pulley  126   c  mounted on the output shaft of the motor  112  through a belt  126   b . Therefore, the rotation of the motor  112  is transmitted to the rotational shaft  124  through the belt  126   b . Thereby, the eccentric portions  125  at both ends of the rotational shaft  124  rotate, causing the coupling elements  121  to move substantially vertically. As a result, the connecting rod  114  reciprocates around the fitting hole  115 , causing the massaging elements  110  to reciprocate substantially vertically to draw a circular arc. When the motor  112  is rotated at a constant speed, the massaging elements  110  reciprocate in a fixed cycle, which corresponds to a tapping operation of the massaging element  110 . When the motor  112  is rotated while changing a rotation speed, the massaging elements  110  reciprocate in a variable cycle, which corresponds to a pressing operation of the massaging elements  110 . 
   As should be appreciated from the above, the massaging elements  110  are driven by the motor  111  to perform the kneading operation and are driven by the motor  112  to perform the tapping operation or the pressing operation. When the massaging elements  110  are driven by both the motors  111  and  112 , the kneading operation and the tapping operation are combined, or the kneading operation and the pressing operation are combined. As a matter of course, these operations may be independently carried out. 
   The massaging system  106  is, as shown in  FIG. 12 , mounted to an up-down base  128 . Rollers  128   a  are mounted at both side ends of the up-down base  128 . The rollers  128   a  are supported on guide rails  129  to be able to roll along them. Nuts (not shown) are provided on the up-down base  128 . A threaded rod  130  is provided in parallel with the guide rails  129  and is threadedly engaged with the nuts. The threaded rod  130  is pivotally mounted at upper and lower end portions thereof. The lower end portion of the threaded rod  130  is coupled to an output shaft of a motor (not shown) provided on a lower portion of the back rest  103 . Therefore, when the threaded rod  130  is driven by the motor to rotate, the up-down base  128  having the nuts is inhibited from rotating integrally with the threaded rod  130  and the nuts and the threaded rod  130  rotate relative to each other because the rollers  128   a  are engaged with the guide rails  129 , so that the up-down base  128  and the massaging system  106  move up and down. With such a construction, when the massaging system  106  moves up and down with the upper half of the body of the user leaning on the back rest  103 , a rolling operation is carried out in such a manner that the massaging elements  110  roll on the back of the user vertically. 
   Subsequently, a construction of the leg rest  104  will be described in detail. For the sake of simple explanation, as described below, the leg rest  104  is illustrated as extended substantially downward from a front end of the seat surface  102   b , except for the condition specifically described.  FIG. 14  is a front view showing the construction of the leg rest  104  provided in the chair-type massaging apparatus  101  according to the fourth embodiment of the present invention.  FIGS. 15 and 16  are plan views of the leg rest  104 . As shown in  FIGS. 14  to  16 , the leg rest  104  of this embodiment mainly includes a support portion  131  and massaging portions  132 . The support portion  131  is of a substantially flat plate shape, and is pivotally mounted at an upper end thereof to a front side of an upper portion of the seat portion  102  by a pivot extending horizontally (see  FIG. 12 ). 
   As shown in  FIGS. 14 to 16 , an intermediate region in the width direction of the support portion  131  forms a support surface  133  on which rear regions of the lower legs of the user, i.e., the calves of the legs of the user, are supported. Mounting surfaces  134  are respectively provided on fight and left sides outside the support surface  133  of the support portion  131  such that they are set one-step lower than the support surface  133  and extend substantially in parallel with the support surface  133 . The massaging portion  132  is mounted to each mounting surface  134  and mainly includes a rear air cell (rear air bag)  135 , a receiver plate  136 , and a front air cell (front air bag)  137 . 
   In the fourth embodiment, the mounting surface  134  is located one-step lower than the support surface  133  to form a step between them; however, the mounting surface and support surface alternatively may form a flat surface. 
     FIG. 17  is a plan cross-sectional view showing a construction of the rear air cell  135  in a contracted state and  FIG. 18  is a plan cross-sectional view showing a construction of the rear air cell  135  in an expanded state. As shown in  FIGS. 17 and 18 , the rear air cell  135  includes a plurality of air bags  135   a  to  135   c  (three in  FIGS. 17 and 18 ) that are superimposed. A hole  138  is provided at a join portion between adjacent air bags  135   a  and  135   b  and a joint portion between the air bags  135   b  and  135   c  to allow the air bags  135   a  to  135   c  to communicate with each other therethrough. An air hose  139  is connected to the air bag  135  in contact with the mounting surface  134  to allow air to be inflowed and outflowed therethrough. A hole (not shown) is provided on the mounting surface  134  of the support portion  131 , and through the hole, the air hose  139  is connected to the air inflow and outflow device  109  provided in the seat portion  102  or in the back rest  103 . The air inflow and outflow device  109  inflows and outflows the air to cause the rear air cell  135  to expand or contract. 
   An outer end of the rear air cell  135 , i.e., an end portion of the rear air cell  135  that is distant from the support surface  133  is expandable in a bellows-like manner. On the other hand, an inner end of the rear air cell  135 , i.e., an end portion of the rear air cell  135  which is closer to the support surface  133  forms an expansion inhibiting portion  135   d  to inhibit the end portions of the air bags  135   a  to  135   c  from traveling away from each other. In the expansion inhibiting portion  135   d , an end portion of the air bag  135   a  and an end portion of the air bag  135   c  are coupled to each other so as not to be away from each other. Since the air bag  135   b  is interposed between the air bags  135   a  and  135   c , an end portion of the air bag  135   b  is not away from these unless the end portions of the air bags  135   a  and  135   c  move away from each other. Thus, the inner end of the rear air cell  135  is configured not to expand. 
   As shown in  FIG. 17 , with the air outflowed from the rear air cell  135 , the rear air cell  135  is substantially flat. In this state, when the air is inflowed to the rear air cell  135 , the outer end of the rear air cell  135  expands with the inner end of the rear air cell  135  remaining unexpanded, and as a result, the rear air cell  135  expands in substantially fan-shaped form as shown in  FIG. 18 . 
   As shown in  FIGS. 14 to 16 , the rear air cell  135  is mounted to the mounting surface  134  in such a manner that the expansion inhibiting portion  135   d  is fixed to the mounting surface  134 . In this construction, the inner end of the rear air cell  135  is configured not to move away from the mounting surface  134  when the rear air cell  135  expands in fan-shaped form. 
   The receiver plate  136  is mounted in front of the rear air cell  135 . The receiver plate  136  is of a substantially rectangular shape and has an area that is slightly larger than that of a main surface of the rear air cell  135  so as to entirely cover the rear air cell  135 . The main surface of the receiver plate  136  has an area that is slightly smaller than that of the mounting surface  134 . The receiver plate  136  is mounted at an inner end intermediate region thereof by a hinge  140  in the vicinity of the step portion between the mounting surface  134  and the support surface  133  of the support portion  131 . The receiver plate  136  is pivotable forward and backward around a pivot extending in the longitudinal direction by the hinge  140 . The receiver plate  136  may be made of a relatively hard material such as a metal, or otherwise may be made of a relatively flexible material such as synthetic resin. 
     FIG. 19  is a partially enlarged plan view showing a hinge structure of the receiver plate  136 . The hinge  140  includes two support elements  140   a  arranged in the vertical direction to protrude and a pin  140   b  connecting the support elements  140   a , in a substantially intermediate region in the longitudinal direction of the mounting surface  134  and in the vicinity of the step portion between the mounting surface  134  and the support surface  133 . An extending portion  140   c  extends from an intermediate region of a base end of the receiver plate  136  and has a width (longitudinal length) slightly smaller than a distance between the support elements  140   a . The extending portion  140   c  is provided with a hole extending in the longitudinal direction, i.e., in the longitudinal direction of the receiver plate  136 . The extending portion  140   c  is provided between the support elements  140   a . The pin  140   b  loosely extends through the hole of the extending portion  140   c . In this manner, the receiver plate  136  is pivotally mounted to the support portion  131 . 
   The receiver plate  136  is biased by a coil spring  140   d  as described below. The coil spring  140   d  includes coil portions  140   e  at both ends thereof, which are coupled to each other by a coupling element (not shown) of a straight line shape. The coil spring  140   d  is formed of spring steel. Each coil portion  140   e  is provided between the extending portion  140   c  and the support element  140   a . The pin  140   b  extends through the coil portions  140   e . Both ends of the coil spring  140   d  extend in a straight line shape. An engagement plate  134   a  is provided to protrude from a region of the mounting surface  134  which are located outward of the support element  140   a . The coil spring  140   d  is engaged at both ends with the engagement plates  134   a . The coupling element of the coil spring  140   d  engages with the extending portion  140   c . Thus, the receiver plate  136  is biased to move closer to the mounting surface  134  by an elastic force exerted by the coil spring  140   d . When the rear air cell  135  expands, the receiver plate  136  rotates forward against the force exerted by the coil spring  140   d , while when the rear air cell  135  contracts, the receiver plate  136  returns to a position which is substantially parallel to the mounting surface  134  by the force of the coil spring  140   d.    
   As a return device for the receiver plate  136 , the illustrated coil spring  140   d  is merely exemplary. Alternatively, a front surface portion of the rear air cell  135  may be bonded to a rear surface of the receiver plate  136  so that the receiver plate  136  returns to a position substantially parallel to the mounting surface  134  upon contraction of the air cell  135 . 
   As shown in  FIGS. 14 to 16 , two front air cells  137  are arranged in the vertical direction on a front surface of the receiver plate  136 . The front air cells  137  are constructed to be similar to and smaller than the rear air cells  135 . As in the rear air cell  135 , the front air cell  137  is substantially flat and expands in fan-shaped form by inflowing air. The width of each front air cell  137  is about half of the width of the receiver plate  136 . Each front air cell  137  is mounted to a substantially outer half region of the front surface of the receiver plate  136 . Each front air cell  137  is placed in such a manner that an unexpandable end is located inward, i.e., closer to the support surface  133 , and an expandable end is located outward, i.e., distant from the support surface  133 . The front air cell  137  is mounted to the receiver plate  136  with the expansion inhibiting portion  137   d  (see  FIGS. 17 and 18 ) fixed to the receiver plate  136 . In this embodiment, the massaging portion constructed above forms an expandable portion of the present invention. 
   While the chair-type massaging apparatus  101  is not in use, the rear air cell  135  and the front air cell  137  respectively contract to cause a front portion of the massaging portion  132  to become substantially flat as shown in  FIG. 15 . As a result, the leg rest  104  forms a substantially flat plate shape, and hence the chair-type massaging apparatus  101  has entirely a simple external appearance. 
   The user seated in the chair-type massaging apparatus  101  in such a state can easily place the lower legs on the leg rest  104  because the front surface of the leg rest  104  is substantially flat. When the lower legs are not massaged or otherwise the chair-type massaging apparatus  101  is used as an easy chair, the lower legs of the user are not restricted and therefore the user can assume a desired posture freely because the front surface of the leg rest  104  is substantially flat. 
   When the rear air cells  135  and the front air cells  137  expand in fan-shaped form with the calves of the user placed on the support surface  133 , the right and left receiver plates  136  rotate forward around the hinges  140  by the expansion of the rear air cells  135  such that the fight and left receiver plates  136  are substantially opposite to the outer regions of the lower legs of the user. Also, by expansion of the front air cells  137 , pressing surfaces which are front surfaces of the left front air cells  137  rotate rightward and rearward and pressing surfaces of the fight front air cells  137  rotate leftward and rearward, thereby pressing outer regions of the shins of the user including acupuncture points such as sanri and horyu inward and rearward. As a result, the user can expect effects such as facilitating of blood circulation, recovery from fatigue, relaxation, function adjustments of internal organs. 
     FIG. 20  is side view for explaining a rotating structure of the leg rest  104 . As shown in  FIG. 20 , a frame structure  141  is mounted inside the seat portion  102 . Direct-acting type actuators  142  and  143  are attached to the frame structure  141 . The actuator  142  is pivotally mounted at one end thereof to the frame structure  141  such that it is pivotable around a pivot extending horizontally and at an opposite end thereof to a lower end portion of the back rest  103  such that it is pivotable around a pivot extending horizontally. The actuators  142  and  143  respectively include electric motors. The rotation of output shafts of the electric motors is converted into straight-line movement, and thus, the actuators  142  and  143  expand and contract. The actuator  142  is mounted to the frame structure  141  at a position forward relative to a position at which the actuator  142  is mounted to the back rest  103 . The actuator  142  is placed to extend substantially forward and backward. The back rest  103  is pivotally mounted in the vicinity of a lower end portion thereof to the frame structure  141  to be pivotable around a pivot  144  extending horizontally. When the actuator  142  expands and contracts, the back rest  103  is pivotable forward and backward around the pivot  144 , thus changing a reclining angle. 
   The actuator  143  is pivotally mounted at one end thereof to the frame structure  141  to be pivotable around a pivot extending horizontally, and at an opposite end thereof to a rear portion of the leg rest  104  to be pivotable around a pivot extending horizontally. The actuator  143  is mounted to the frame structure  141  at a position rearward relative to a position at which the actuator  143  is mounted to the leg rest  104 . The actuator  143  is placed to extend substantially forward and backward. The leg rest  104  is pivotally mounted at an upper end thereof to the frame structure  141  to be pivotable around a pivot  145  extending horizontally. When the actuator  143  expands and contracts, the leg rest  104  is pivotable forward and backward around a pivot  145 , thus changing a tilting angle of the leg rest  104 . 
   In the fourth embodiment, the reclining device of the back rest  103  and the rotation device of the leg rest  104  are the direct-acting type actuators  142  and  143  including the motors; however, these are merely exemplary. Alternatively, other direct-acting type actuators including air cylinders or linear motors may be used. In addition, air bags may cause the back rest  103  or the leg rest  104  to pivot. In a further alternative, the back rest  103  may be reclined manually or the leg rest  104  may be rotated manually. 
     FIG. 21  is a block diagram showing a part of a configuration of the chair-type massaging apparatus  101  according to the fourth embodiment of the present invention. As shown in  FIG. 21 , the chair-type massaging apparatus is provided with a control circuit  146 . The control circuit  146  includes a CPU, ROM, RAM, an input/output interface, etc and is provided inside the seat portion  102  or the back rest  103 . The control circuit  146  is coupled to an operation portion  147  provided with a plurality of operation keys and to drive circuits  148  to  150 . The control circuit  146  is configured to receive an operation signal from the operation portion  147  and to transmit a control signal according to the operation signal to the drive circuits  148  to  150 . The operations of the chair-type massaging apparatus  101  according to the operation keys and their combinations are preset in the control circuit  146 . When the user presses an operation key corresponding to a desired operation, the operation signal is transmitted to the control circuit  146 , which outputs a control signal corresponding to the operation input. 
   The drive circuits  148  and  149  are coupled to the direct-acting type actuators  142  and  143 , respectively. This makes it possible to freely change the reclining angle of the back rest  103  and the tilting angle of the leg rest  104  according to the user&#39;s operation with the operation portion  147 . 
   The drive circuit  150  is coupled to the air inflow and outflow device  109  and is configured to drive the air inflow and outflow device  109  according to the control signal received from the control circuit  146 . The control circuit  146  is configured to control the operation of the air inflow and outflow device  109 . The air inflow and outflow device  109  includes a switching valve such as an electromagnetic valve, an air pump, and other components, and is coupled to the rear air cells  135  and the front air cells  137  through air hoses  139 . The air inflow and outflow device  109  is capable of independently inflowing and outflowing air respectively to each of the rear air cells  135  and the front air cells  137 . 
   An operation control of the leg rest  104  will be described.  FIG. 22  is a flowchart showing an example of the operation control of the leg rest  104  in the chair-type massaging apparatus  101  according to the fourth embodiment of the present invention. When the user seated in the chair-type massaging apparatus  101  performs a predetermined input operation to instruct the leg rest  104  to start massaging the lower legs (step S 1 ), the control circuit  146  sends a predetermined control signal to the drive circuit  150  to control the operation of the air inflow and outflow device  109  so that the air is inflowed to the rear air cells  135  for a preset time period (step  52 ). This causes the receiver plates  136  to rotate forward. Thereafter, the receiver plates  136  are fixed when the air inflow to the rear air cells  135  stops. 
   Subsequently, the control circuit  146  sends a predetermined control signal to the drive circuit  150  to control the operation of the air inflow and outflow device  109  so that the air is inflowed to the front air cells  137  for a preset time period (step S 3 ). This causes the front air cells  137  to expand in fan-shaped form to press outer regions of the shins of the user inward and rearward. 
   After a set time period elapses from the start of the air inflow to the front air cells  137 , the control circuit  146  sends a predetermined control signal to the drive circuit  150  to control the operation of the air inflow and outflow device  109  so that the air is outflowed from the front air cells  137  (step S 4 ). This releases the pressing force applied to the outer regions of the shins of the user. 
   The control circuit  146  determines whether or not there is an instruction from the user for terminating massaging the lower legs (step  55 ). If it is determined that there is no instruction, the control circuit  146  returns the process to step  53 . On the other hand, if it is determined that there is an instruction in step  55 , the control circuit  146  sends a predetermined control signal to the drive circuit  150  to control the operation of the air inflow and outflow device  109  so that the air is outflowed from the rear air cells  135  (step S 6 ), thus terminating the process. 
   The front air cells  137  repeat expansion and contraction to repeatedly press the outer regions of the shins of the user unless the instruction for terminating massaging the lower legs is received from the user. The massage strength of the lower legs can be adjusted by the user&#39;s predetermined input operation with the operation portion  147  in such a manner that in order to increase the massage strength, the time period during which the air is inflowed to the rear air cells  135  is set longer, while in order to decrease the massage strength, the time period during which the air is inflowed to the rear air cells  135  is set shorter. It shall be appreciated that the time period during which the air is inflowed to the front air cells  137  may be configured to be changed. 
   Furthermore, instead of changing the time periods during which the air is inflowed to the rear air cells  135  and the front air cells  137 , an air inflow amount for the same time period may be adjusted, thus adjusting the massage strength. 
   The number and size of the rear air cells  135 , the receiver plates  136 , and the front air cells  137  are not intended to be limited to those illustrated in the fourth embodiment. Alternatively, the rear air cells  135 , the receiver plates  136 , and the front air cells  137  may be substantially equally sized and one of them may be mounted for each lower leg of the user. Also, the rear air cell  135  and the front air cell  137  need not be superimposed with the receiver plate  136  interposed between them. For example, each of the rear air cell  135  and the front air cell  137  may include only one air bag or otherwise may be superimposed without the receiver plate  136 . Furthermore, they may include three or more air bags superimposed. 
   Embodiment 5 
     FIG. 23  is a perspective view showing a construction of an entire chair-type massaging apparatus  152  according to a fifth embodiment of the present invention. As shown in  FIG. 23 , the chair-type massaging apparatus  152  is constructed such that a leg rest  153  is pivotally mounted at an upper end thereof to an upper front side of the seat portion  102 . An intermediate massaging portion  155  is mainly comprised of an intermediate air cell (intermediate air bag)  154  (see  FIGS. 24 to 26 ) and is provided in substantially an intermediate region in a width direction of the leg rest  153 . 
   The construction of the leg rest  153  will be described in detail. As described below, for the simplicity of explanation, the leg rest  153  is illustrated as extended substantially downward from a front end of the seat surface  102   b , except for a case specifically described.  FIG. 24  is a front view showing the construction of the leg rest  153  included in the chair-type massaging apparatus  152  according to the fifth embodiment of the present invention.  FIGS. 25 and 26  are plan views thereof. As shown in  FIGS. 24 to 26 , the leg rest  153  mainly includes a support portion  156 , the intermediate massaging portion  155 , and massaging portions  132 . The support portion  156  forms a substantially flat plate shape, and is pivotally mounted at an upper end thereof to the upper front side of the seat portion  102  by a pivot extending horizontally (see  FIG. 23 ). 
   As shown in  FIGS. 24 to 26 , an intermediate mounting surface  157  is formed in an intermediate region in the width direction of the support portion  156  and configured to allow the intermediate massaging portion  155  to be mounted thereon. Support surfaces  158  are formed on right and left sides outside the intermediate mounting surface  157  of the support portion  156  and are configured to allow the right and left calves of the user to be supported thereon. Further, mounting surfaces  159  are formed outside the support surfaces  158  and are configured to allow the massaging portions  132  to be mounted thereon. The intermediate mounting surface  157 , the support surfaces  158  and the mounting surfaces  159  are parallel to each other. The intermediate mounting surface  157  is formed lower than the support surfaces  158 , and the mounting surfaces  159  are formed lower than the intermediate mounting surface  157 . Thus, there are step portions between the intermediate surface  157  and the support surfaces  158  and between the mounting surfaces  159  and the support surfaces  158 . As shown in  FIG. 24 , the intermediate mounting surface  157  is formed to have a width that increases in a downward direction, and the step portions between the intermediate mounting surface  157  and the support surfaces  158  are tilted with respect to the longitudinal direction to have a spacing between them that increases in a downward direction. 
   Alternatively, the support surfaces  158  and the intermediate mounting surface  157  may form a flat surface, or otherwise the support surfaces  158  and the mounting surfaces  159  may form a flat surface. 
   An intermediate air cell  154  is mounted to the intermediate mounting surface  157 . The intermediate air cell  154  has a dimension slightly smaller than that of the intermediate mounting surface  157  and has a width that increases in a downward direction, as in the intermediate mounting surface  157 . The intermediate air cell  154  in a contracted state is substantially flat so as to form a flat surface along with the support surfaces  158 . In this state, the intermediate air cell  154  expands to protrude forward further than the support surfaces  158  by inflowing the air. 
   Alternatively, the lower legs of the user need not be supported only by the support surfaces  158 , but a part of the calves may be supported by the support surfaces  158  and the remaining part of them may be supported by the intermediate air cell  154 . 
     FIG. 27  is a block diagram showing a part of a configuration of the chair-type massaging apparatus  152  according to the fifth embodiment of the present invention. As shown in  FIG. 27 , the control circuit  146  is coupled to drive circuits  148 ,  149 , and  160  and is configured to send a control signal to them. The drive circuit  160  is coupled to an air inflow and outflow device  161  and is configured to drive the air inflow and outflow device  161  in accordance with the control signal received from the control circuit  146 . The control circuit  146  is capable of controlling an operation of the air inflow and outflow device  161 . The air inflow and outflow device  161  includes a switching valve such as an electromagnetic valve, an air pump, and other components, and is coupled to the rear air cells  135 , the front air cells  137 , and the intermediate air cell  154  through the air hoses  139 . The air inflow and outflow device  161  is configured to inflow and outflow air to and from each of the rear air cells  135 , the front air cells  137 , and the intermediate air cell  154  independently. 
   An operation control of the leg rest  153  will be described.  FIG. 28  is a flowchart showing an example of the operation control of the leg rest  153  in the chair-type massaging apparatus  152  according to the fifth embodiment of the present invention. When the user seated in the chair-type massaging apparatus  152  performs a predetermined input operation with an operation portion  147  to instruct the leg rest  153  to start massaging the lower legs (step S 21 ), the control circuit  146  sends a predetermined control signal to the drive circuit  160  to control the operation of the air inflow and outflow device  161  so that the air is inflowed to the intermediate air cell  154  for a preset time period (step S 22 ). This causes the intermediate air cell  154  to protrude forward further than the support surfaces  158 . Thus, the user only has to move the lower legs so that inner regions of the calves are pressed against the intermediate air cell  154 , in order to assume a proper posture to enable the lower legs to be massaged. Steps S 23  to S 27  following the step S 22  are identical to the steps S 2  to S 6  described in the fourth embodiment, and will not be further described. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus  152  of the fifth embodiment are identical to those of the chair-type massaging apparatus  101  of the fourth embodiment, the same components are identified by the same reference numerals and their configurations, functions and effects will not be further described. 
   In the chair-type massaging apparatus  152  of the fifth embodiment constructed as described above, while it is not used, the rear air cells  135 , the front air cells  137 , and the intermediate air cell  154  respectively contract to cause front regions of the massaging portions  132  and the intermediate massaging portion  155  to form a substantially flat surface as shown in  FIG. 25 , and thus the leg rest  153  forms a substantially flat plate shape. As a result, the chair-type massaging apparatus  152  entirely has a simple external appearance. 
   With the user seated in the chair-type massaging apparatus  152  in such a state, the user easily places the lower legs onto the leg rest  153  because the front surface of the leg rest  153  is a substantially flat surface. When the lower legs are not massaged, or the chair-type massaging apparatus  152  is otherwise used as an easy chair, the user can assume a desired posture freely without restriction of the lower legs because the front surface of the leg rest  153  is the substantially flat surface. 
   When the intermediate air cell  154  expands, the inner regions of the calves of the user contact the intermediate air cell  154 . As shown in  FIG. 26 , when the rear air cells  135  and the front air cells  137  respectively expand in this state, the outer regions of the shins of the user are pressed inward and rearward by the pressing surfaces of the front air cells  137 . As a result, each lower leg of the user is sandwiched between the front air cell  137  and the intermediate air cell  154  to be subjected to grab-massage. 
   As used herein, the term “grab-massage” refers to a massage operation in which a massager such as a massage person applies a finger pressure to massage the leg or the arm of the user in such a manner that the massager grabs the leg or the arm while applying strong and weak forces. The grab-massage is one of massage operations which may be comfortable to the user. 
   Since the intermediate air cell  154  is mounted to the support portion  156  to have a width that increases in the downward direction, it contacts large regions in the longitudinal direction of the legs. Thereby, it is possible to avoid the intermediate air cell  154  contacting only a longitudinal part of the calves of the user. 
   While in the fifth embodiment, the intermediate air cell  154  is configured to have the width that increases in a downward direction, it may alternatively have a rectangular shape. 
   Since the inner regions of the calves of the user contact the intermediate air cell  154 , it is possible to inhibit the lower legs of the user from moving inward even when the outer regions of the shins of the user are pressed inward and rearward. As a result, the massaging effects are enhanced as compared to the case where only the massaging portions  132  massage the outer regions of the shins. 
   The operation control of the leg rest  153  is not limited to the above. For example, an operation cycle may be repeated in such a manner that only the rear air cells  135  may contract and thereafter the front air cells  137  and the intermediate air cell  154  may respectively contract in the state in which the rear air cells  135 , the front air cells  137 , and the intermediate air cell  154  respectively expand. In this case, with the rear air cells  135 , the front air cells  137  and the intermediate air cell  154  respectively expanded, the lower leg of the user is sandwiched between the massaging portion  132  and the intermediate massaging portion  155 . In this state, by contracting only the rear air cells  135 , the front air cells  137  are caused to retract by an elastic force exerted by the coil spring  140   d . Therefore, the lower leg of the user is pulled rearward with the lower leg sandwiched between the massaging portion  132  and the intermediate massaging portion  155 . Thus, the lower leg of the user is subjected to pull massage. 
   As used herein, the term “pull-massage” refers to a massage operation in which the massager grabs a region of the user, for example, the lower leg, to be massaged, and shifts a massage position (position at which finger or the like is in contact with a body of the user) outward relative to the massage position while grabbing the region to be massaged. The pull-massage is one massage operation that may be comfortable to the user. 
   Alternatively, the operation of the leg rest  153  may be controlled so that the front air cells  137  and the intermediate air cell  154  expand and contract repeatedly in synchronization with each other with the rear air cells  135  expanded. In this case, the grab-massage of the lower legs of the user is repeatedly performed. 
   As in the fourth embodiment, the number and size of the rear air cells  135 , the receiver plates  136 , and the front air cells  137  are not intended to be limited to those illustrated in the fifth embodiment. Also, the rear air cell  135  and the front air cell  137  need not be superimposed with the receiver plate  136  interposed between them. For example, each of the rear air cell  135  and the front air cell  137  may include only one air bag or otherwise may be superimposed without the receiver plate  136 . Furthermore, they may include three or more air bags superimposed. 
   Furthermore, the number and size of the intermediate air cell  154  are not intended to be limited to those of the fifth embodiment, but a plurality of intermediate air cells  154  may be arranged in the vertical direction, or otherwise the intermediate air cell  154  may include a plurality of air bags. 
   Embodiment 6 
     FIG. 29  is a perspective view showing a construction of an entire chair-type massaging apparatus according to a sixth embodiment of the present invention. As shown in  FIG. 29 , a chair-type massaging apparatus  162  of this embodiment is constructed such that a leg rest  163  is pivotally attached at an upper end portion thereof to an upper front side of the seat portion  102 , and an intermediate massaging portion  166  mainly includes a pair of intermediate air cells  164  (see  FIGS. 30 to 32 ) mounted at an intermediate region in the width direction of the leg rest  163 . 
   Subsequently, a construction of the leg rest  163  will be described in more detail. As described below, for the sake of simple explanation below, the leg rest  163  is illustrated as extended substantially downward from a front end of the seat surface  102   b , except for the condition specifically described.  FIG. 30  is a front view showing the construction of the leg rest  163  provided in the chair-type massaging apparatus  162  according to the sixth embodiment of the present invention.  FIGS. 31 and 32  are plan views thereof. As shown in  FIGS. 30 to 32 , the leg rest  163  of this embodiment includes a support portion  165  and the massaging portions  132 . The support portion  165  includes an intermediate mounting surface  167  (trapezoid region defined by two-dotted line in  FIG. 30 ) at a substantially intermediate region in the width direction thereof. Support surfaces  168  are formed on right and left sides outside the intermediate mounting surface  167  of the support portion  165  and are configured to allow the right and left calves of the user to be supported thereon. Mounting surfaces  169  are provided outside the support surfaces  168  and are configured to allow the massaging portions  132  to be mounted thereon. The intermediate mounting surface  167 , the support surfaces  168  and the mounting surfaces  169  are parallel to each other. The intermediate mounting surface  167  is as high as the support surfaces  168  to form a flat surface, and the mounting surfaces  169  are lower than the intermediate mounting surface  167  and the support surfaces  168 . Thus, there are step portions between the mounting surfaces  169  and the support surfaces  168 . Alternatively, the mounting surfaces  169  and the support surfaces  168  may form a flat surface, or otherwise there may be step portions between the intermediate mounting surface  167  and the support surfaces  168  so that the intermediate mounting surface  167  is lower than the support surfaces  168 . 
   A pair of right and left intermediate air cells  164  are mounted to the intermediate mounting surface  167 . Each intermediate air cell  164  is shaped to have a reduced width of the rear air cell  135 . As in the rear air cell  135  and the front air cell  137 , each intermediate air cell  164  is configured to expand in fan-shaped form from a substantially flat state by air inflow. The respective intermediate air cells  164  are mounted to the intermediate mounting surface  167  in such a manner that their expandable ends are closer to each other and their unexpandable ends are distant from each other, and a distance between them increases in a downward direction. As in the mounting structure of the rear air cell  135  to the support surface  133  described in the fourth embodiment, each intermediate air cell  164  is mounted to the intermediate mounting surface  167  such that an expansion restricting portion  164   d  is fastened to the intermediate mounting surface  167 . 
   While the intermediate air cells  164  are mounted to the intermediate mounting surface  167  to be tilted, they may alternatively be mounted to the intermediate mounting surface  167  to be arranged in parallel with each other. 
   The lower legs of the user are not necessarily supported only by the support surfaces  168 . Alternatively, a part of the calves may be supported by the support surfaces  168  and a remaining part may be supported by the intermediate air cells  164  in a contracted state. In this case, the intermediate air cells  164  are always in contact with the lower legs of the user. Thus, the pressing force of the intermediate air cells  164  may be applied to the lower legs of the user more efficiently. 
     FIG. 33  is a block diagram showing a part of a configuration of the chair-type massaging apparatus  162  according to the sixth embodiment of the present invention. As shown in  FIG. 33 , the control circuit  146  is coupled to the drive circuits  148 ,  149 , and  170  and is configured to send a control signal to them. The drive circuit  170  is coupled to an air inflow and outflow device  171  and is configured to drive the air inflow and outflow device  171  in accordance with the control signal received from the control circuit  146 . The control circuit  146  is capable of controlling an operation of the air inflow and outflow device  171 . The air inflow and outflow device  171  includes a switching valve such as an electromagnetic valve, an air pump, and other components, and is coupled to the rear air cells  135 , the front air cells  137 , and the intermediate air cells  154  through air hoses  139 . The air inflow and outflow device  171  is configured to inflow and outflow air to and from each of the rear air cells  135 , the front air cells  137 , and the intermediate air cells  154  independently. 
   Subsequently, an operation control of the leg rest  163  will be described.  FIG. 34  is a flowchart showing an example of the operation control of the leg rest  163  in the chair-type massaging apparatus  162  according to the sixth embodiment of the present invention. When the user seated in the chair-type massaging apparatus  162  performs a predetermined input operation with the operation portion  147  to instruct the leg rest  163  to start massaging the lower legs (step S 31 ), the control circuit  146  sends a predetermined control signal to the drive circuit  170  to control the operation of the air inflow and outflow device  171  so that the air is inflowed to the rear air cells  135 , the front air cells  137  and the intermediate air cells  164  for a preset time period (step S 32 ). This causes the rear air cells  135 , the front air cells  137 , and the intermediate air cells  164  to respectively expand to an extent to which the front air cells  137  contact the outer regions of the shins of the user and the intermediate air cells  164  contact the inner regions of the calves. In this state, each lower leg is sandwiched between and pressed by the front air cells  137  and the intermediate air cell  164 . 
   Since the intermediate air cells  164  are mounted to the support portion  165  with a distance between them that increases in a downward direction, they contact large regions in the longitudinal direction of the lower legs. Thereby, it is possible to avoid the intermediate air cells  164  contacting only a longitudinal part of the calves of the user. 
   After an elapse of the set time period from when the air inflow to the rear air cells  135 , the front air cells  137 , and the intermediate air cells  164  starts, the control circuit  146  sends a predetermined control signal to the drive circuit  170  to control the operation of the air inflow and outflow device  171  so that the air is outflowed from the rear air cells  135  (step  533 ). This causes the rear air cells  135  to contract. The receiver plates  136  rotate rearward by the force exerted by the coil springs  140   d , and the front air cells  137  retract. Thus, the pull massage is performed on the lower leg of the user in such a manner that the lower leg of the user is pulled rearward with the lower leg sandwiched between the front air cell  137  and the intermediate air cell  164 . 
   After an elapse of a predetermined time period from when the air outflow from the rear air cells  135  starts, the control circuit  146  sends a predetermined control signal to the drive circuit  170  to control the operation of the air inflow and outflow device  171  so that the air is outflowed from the front air cells  137  and the intermediate air cells  164  (step  534 ). Thereby, the pressing force applied to the lower legs of the user is released. 
   The control circuit  146  determines whether or not there is an instruction from the user for terminating massaging of the lower legs (step S 35 ), and if it is determined that there is no instruction, the control circuit  146  returns the process to step S 32 . On the other hand, if it is determined that there is an instruction in step S 35 , the control circuit  146  terminates the process. 
   The leg rest  163  repeats pull-massage of the lower legs unless there is an instruction from the user for terminating massaging of the lower legs. The massage strength of the lower legs is adjustable by the user&#39;s predetermined input operation with the operation portion  147  in such a manner that in order to increase the massage strength, the time period during which the air is inflowed to the rear air cells  135 , the front air cells  137  and the intermediate air cells  164  is set longer, while in order to decrease the massage strength, the time period during which the air is inflowed to them is set shorter. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus  162  of the sixth embodiment are identical to those of the chair-type massaging apparatus  101  of the fourth embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   As in the fourth embodiment, the number and size of the rear air cells  135 , the receiver plates  136  and the front air cells  137  are not intended to be limited to those illustrated in the sixth embodiment. Also, the rear air cell  135  and the front air cell  137  need not be superimposed with the receiver plate  136  interposed between them. For example, each of the rear air cell  135  and the front air cell  137  may include only one air bag or otherwise may be superimposed without the receiver plate  136 . Furthermore, they may include three or more air bags superimposed. 
   The number and size of the intermediate air cells  164  are not intended to be limited to those of the sixth embodiment. The intermediate air cells  164  may be configured in such a manner that a plurality of intermediate air cells  164  may be arranged in two lines in the vertical direction, or otherwise may be comprised of a plurality of air bags. 
   Embodiment 7 
     FIG. 35  is a front view showing a construction of a leg rest  172  of a chair-type massaging apparatus according to a seventh embodiment of the present invention.  FIGS. 36 and 37  are plan views thereof.  FIG. 38  is a partially enlarged plan view of the leg rest  172  of  FIG. 37 . As shown in  FIGS. 35 to 37 , each massaging portion  240  of the leg rest  172  of the seventh embodiment is constructed such that two pressing heads (massaging elements)  173  are arranged in the longitudinal direction on a front side of each front air cell  137 . In greater detail, as shown in  FIG. 38 , a pressing plate  174  having a main surface of a substantially the same shape as that of a front surface of each front air cell  137  is mounted to the front surface of the front air cell  137 , and the two pressing heads  173  are arranged in the vertical direction on the front surface of the pressing plate  174 . When the rear air cells  135  and the front air cells  137  expand, the pressing heads  173  press the outer regions of the shins of the user to apply stimulation to the user as if the massager were pressing the outer regions of the shins. 
   The pressing heads  173  may be made of materials that are not specifically limited, for example, metal or synthetic resin, but preferably elastomer having an elasticity, various types of urethane foams, other foams, etc. This makes it possible to inhibit too strong stimulation from being applied to the user. The shape of the pressing heads  173  is not specifically limited, but may be round, for example, hemispherical. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus of the seventh embodiment are identical to those of the chair-type massaging apparatus  162  of the sixth embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   As in the fourth embodiment, the number and size of the rear air cells  135 , the receiver plates  136  and the front air cells  137  are not intended to be limited to those illustrated in the seventh embodiment. Also, the rear air cell  135  and the front air cell  137  need not be superimposed with the receiver plate  136  interposed between them. For example, each of the rear air cell  135  and the front air cell  137  may include only one air bag or may be superimposed without the receiver plate  136 . Furthermore, they may include three or more air bags superimposed. 
   As in the sixth embodiment, the number and size of the intermediate air cells  164  are not intended to be limited to those of the seventh embodiment. The intermediate air cells  164  may be configured in such a manner that a plurality of intermediate air cells  164  may be arranged in two lines in the vertical direction, or otherwise may be comprised of a plurality of air bags. 
   Embodiment 8 
     FIG. 39  is a front view showing a construction of a leg rest of a chair-type massaging apparatus according to an eighth embodiment of the present invention.  FIGS. 40 and 41  are plan views thereof. As shown in  FIGS. 39 to 41 , each receiver plate  176  included in a massaging portion  241  of a leg rest  175  is configured such that its outer end portion in the width direction is bent forward a predetermined angle. The front air cells  137  are mounted to the receiver plate  176  at a position which is outward relative to the bent position. As shown in  FIG. 41 , each rear air cell  135  is expandable to an extent to which a base end portion of the receiver plate  176  becomes perpendicular to the support surface  168 . When the rear air cell  135  expands, the outer end portion of the receiver plate  176  covers the support surface  168  from the front. The receiver plate  176  may be made of materials having hardness sufficient to maintain the bent state, and is preferably made of materials having relatively high hardness, for example, metal or plastic having plasticity at temperatures near a room temperature. 
   In contrast to the configuration in which the receiver plate is flat, the front air cell  137  is moved closer to the lower leg of the user when the rear air cell  135  expands. Therefore, by expanding the front air cell  137 , a front region of the lower leg including the outer region of the shin of the user is pressed substantially backward, and thus stronger stimulation is applied to the outer region of the shin. Furthermore, if the front air cell  137  is made smaller, sufficient massage strength can be ensured. 
   Instead of a receiver plate  176  that is bent forward at one point, the receiver plate  176  may alternatively be entirely curved forward in a circular arc shape. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus of the eighth embodiment are identical to those of the chair-type massaging apparatus  162  of the sixth embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   As in the fourth embodiment, the number and size of the rear air cells  135 , the receiver plates  136  and the front air cells  137  are not intended to be limited to those illustrated in the eighth embodiment. Furthermore, two or more air bags may be superimposed on the front surface of the receiver plate  176 , or otherwise may be superimposed behind the receiver plate  176 . 
   As in the sixth embodiment, the number and size of the intermediate air cells  164  are not intended to be limited to those of the eighth embodiment. The intermediate air cells  164  may be configured in such a manner that a plurality of intermediate air cells  164  may be arranged in two lines in the vertical direction, or otherwise may be comprised of a plurality of superimposed air bags. 
     FIG. 42  is a front view showing another construction of the leg rest of the chair-type massaging apparatus according to the eighth embodiment of the present invention.  FIGS. 43 and 44  are plan views thereof. As shown in  FIGS. 42 to 44 , a leg rest  242  is constructed in such a manner that an intermediate mounting surface  167  of the support portion  165  is rectangular (region defined by two-dotted line in  FIG. 42 ) and an intermediate massaging portion  244  including a rectangular flat intermediate air cell  243  is mounted to intermediate mounting surface  167  instead of the intermediate massaging portion  166  including a pair of intermediate air cells  164 . The intermediate air cell  243  is flat in a contracted state, and hence the front surface of the support portion  165  is substantially flat. When the intermediate air cell  243  expands, it protrudes forward from the support surface  168  so as to contact and press the inner region of the calf of the user. When the user places the lower leg on the support portion  165  such that the inner region of the calf contacts the intermediate air cell  243 , the calf of the user is guided to a massage position on the support surface  168 . 
   The shape of the intermediate air cell  243  is not intended to be limited to a rectangle shape, but may be a trapezoid shape with a width increasing in a downward direction. 
   The number, size, and configuration of the intermediate air cell(s)  243  are not intended to be limited to the above. The intermediate air cell(s)  243  may be configured in such a manner that a plurality of intermediate air cells  243  may be arranged in two lines in the vertical direction, or otherwise may be comprised of a plurality of superimposed air bags. 
   Embodiment 9 
     FIG. 45  is a front view showing a construction of a leg rest  177  of a chair-type massaging apparatus according to a ninth embodiment of the present invention.  FIG. 46  is a side view thereof. As shown in  FIGS. 45 and 46 , the leg rest  177  of the ninth embodiment includes a lower leg massaging unit  178  configured to massage the lower leg of the user, i.e., a region from the knee to the ankle, and a foot massaging unit  179  configured to massage a foot of the user, i.e., a region from the ankle to tip portion. The lower leg massaging unit  178  is identical in construction to the leg rest  163  described in the seventh embodiment except that the intermediate massaging portion  180  includes two pairs of intermediate air cells  181 , and each of right and left massaging portions  183  includes rear air cells  184  and receiver plates  185  which are formed by dividing the rear air cell  135  and the receiver plate  136  in two in the vertical direction and by arranging them in the vertical direction. In greater detail, the intermediate massaging portion  180  is constructed such that a pair of intermediate air cells  181  are arranged on right and left sides of an upper half region of the intermediate mounting surface  167  and another pair of intermediate air cells  181  are arranged on right and left sides on a lower half region of the intermediate mounting surface  167 . Each pair of intermediate air cells  181  are arranged to be tilted with respect to the longitudinal direction such that a distance between them increases in a downward direction. Also, the two intermediate air cells  181  arranged in the longitudinal direction, i.e., two intermediate air cells  181  arranged on the right side or on the left side are arranged in a straight line shape. Thereby, the intermediate air cells  181  contact a large region of the lower legs in the longitudinal direction while the lower legs of the user are massaged. Therefore, the intermediate air cells  181  contacting only a longitudinal part of the calves of the user is avoided. 
   Subsequently, a construction of the massaging portion  183  will be described in detail. The two rear air cells  184  are vertically arranged on each mounting surface  169 . As in the rear air cells  135  and the front air cells  137  described in the fourth embodiment, each rear air cell  184  is configured to expand in fan-shaped form from a substantially flat state by inflowing the air thereto. Each rear air cell  184  has a main surface portion which is slightly smaller than an upper half region (or lower half region) of the mounting surface  169 , and is placed on the mounting surface  169  as in the rear air cell  135  in such a manner that its unexpandable end is oriented inward, i.e., toward the support surface  168 , and its expandable end is oriented outward. 
   The receiver plate  185  is placed in front of each rear air cell  184  thus configured. Each receiver plate  185  is constructed of a substantially rectangular plate having an area slightly larger than that of the main surface portion of the rear air cell  184 , and is placed in front of the rear air cell  184  so as to cover the entire rear air cell  184 . Each receiver plate  185  is mounted to the mounting surface  169  by a hinge  186  as in the receiver plate  136  of the fourth embodiment, which will not be described in detail. One front air cell  137  is mounted in an outer half region of the front surface of the receiver plate  185  as in the fourth embodiment. As in the receiver plate  136  of the fourth embodiment, the receiver plate  185  may be constructed of a relatively hard material such as metal, or otherwise a relatively flexible material such as synthetic resin. 
   In the manner described above, the massaging portion  183  is constructed of the rear air cells  184 , the receiver plates  185 , and the front air cells  137 . 
   Each foot massaging unit  179  includes a sole support portion  187  of a substantially flat plate shape, and a sole massaging portion  192  comprised of air cells (air bags)  188  to  191 , and a vibrator (not shown). As in the rear air cell  135  and the front air cell  137 , the air cells  188  to  191  are configured to expand in fan-shaped form from a substantially flat state by inflowing air thereto. An intermediate mounting surface  193  is formed in an intermediate region in the width direction of the sole support portion  187  and configured to allow the air cell  188  and the vibrator to be mounted thereon. Support surfaces  194  are provided on right and left regions outside the intermediate mounting surface  193  of the sole support portion  187  and configured to allow the sole of the user to be supported thereon. Mounting surfaces  195  are provided on outer end regions of upper surfaces of the sole support portions  187  to be positioned on right and left regions outside the support surfaces  194 . The intermediate mounting surface  193 , the support surfaces  194 , and the mounting surfaces  195  are parallel to each other. The intermediate mounting surface  193  is formed lower than the support surfaces  194  and the mounting surfaces  195  are formed lower than the intermediate mounting surface  193 . In this manner, there are steps between the intermediate mounting surface  193  and the support surfaces  194  and between the mounting surfaces  195  and the support surfaces  194 . 
   The support surface  194  and the intermediate mounting surface  193  may form a flat surface, or otherwise the support surface  194  and the mounting surface  195  may form a flat surface. 
   A pair of air cells  188  are arranged on right and left sides on a front half region of the intermediate mounting surface  193 . The air cells  188  are mounted to the intermediate mounting surface  193  in such a manner that their expandable ends are closer to each other and their unexpandable ends are distant from each other. 
   The vibrators are mounted in regions of the intermediate mounting surface  193  which are located behind the two air cells  188 . Each vibrator is positioned to correspond to an arch of the foot of a user with a standard frame, with the foot placed on the foot massaging unit  179 . 
   An air cell  189  is mounted in a front half region of the mounting surface  195  to be located at a position lateral relative to the air cell  188 . The air cell  189  has a main surface sized to be slightly smaller than a front half region of the mounting surface  195 , and is placed in such a manner that its unexpandable end is oriented inward. A receiver plate  196  having a main surface of substantially the same shape as that of the upper surface of the air cell  189  is mounted on the upper surface of the air cell  189 . Furthermore, an air cell  191  is mounted on an upper surface of the receiver plate  196 . Since placement and construction of these air cells  189  and  191  and the receiver plate  196  are identical to those of the rear air cell  135 , the receiver plate  136 , and the front air cell  137  described in the fourth embodiment, they will not be further described. 
   An air cell  190  is mounted to a rear half region of the mounting surface  195  to be located at a position lateral relative to the vibrator. The air cell  190  is sized to be slightly smaller than the air cell  189 , and is placed in such a manner that its unexpandable end is oriented inward as in the air cell  189 . 
     FIG. 47  is a front view showing a construction of the leg rest  177  with the air cells  188  to  191  expanded.  FIG. 48  is a side view thereof. With the sole of an adult user of a standard frame placed on the sole massaging unit  179 , a part of the sole is placed on the support surface  194  and the remaining part is placed on the air cell  188  and the vibrator. Under this condition, by expanding the air cells  189  and  191 , a top surface of the foot of the user is pressed from above by the air cell  191  as shown in  FIGS. 47 and 48 . Thus, the top surface of the foot of the user is massaged. In addition, when the air cells  188  and  190  and the vibrator operate with the foot of the user pressed from above, the foot of the user is inhibited from moving away therefrom due to pressure or vibration of them. 
   By expanding the air cell  188 , the tip portion of the foot of the user from a bottom region to an inner region is pressed. Further, by expanding the air cell  190 , an ankle (malleolus) of the user is pressed. By operating the vibrator, the vibrational stimulation is applied to the arch of the foot of the user. 
   By repeating expansion and contraction of the air cells  188  to  191  independently or in synchronization with each other, or by operating the vibrator independently or in synchronization with these air cells  188  to  191 , comfortable stimulation is applied to the user while the foot is massaged. 
   As shown by two-dotted lines in  FIGS. 45 to 48 , the lower leg massaging unit  178  and the foot massaging unit  179  are coupled by a frame  197  to configure the leg rest  177 . In this case, the frame  197  may be provided with an expansion and contraction system to vary a distance between the lower leg massaging unit  178  and the foot massaging unit  179 . Alternatively, instead of coupling the lower leg massaging unit  178  to the foot massaging unit  179  by the frame  197  or the like, only the lower leg massaging unit  178  may be pivotally mounted on the seat portion  102 , and the foot massaging unit  179  may be placed on a floor surface under the lower leg massaging unit  178  during use. 
   The above mentioned configuration of the lower leg massaging unit  178  is merely exemplary, and it may be configured as the leg rest of any of the fourth to ninth embodiments. In addition, the above mentioned configuration of the foot massaging unit  179  is merely exemplary. The foot massaging unit  179  may be configured in such a manner that the air cells  189  and  191  and the receiver plate  196  may be omitted, and/or one or a plurality of the air cells  189  and  191  and the receiver plate  196  may be omitted, another air cells or vibrators may be provided separately from the air cells  188  to  191  and the vibrator, or otherwise one or a plurality of the air cells  188  to  191  and the vibrator may be placed at positions different from those mentioned above. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus of the ninth embodiment are identical to those of the chair-type massaging apparatus  101  of the fourth embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   As in the fourth embodiment, the number and size of the rear air cells  184 , the receiver plates  185  and the front air cells  137  are not intended to be limited to those illustrated in the ninth embodiment. Also, the rear air cell  184  and the front air cell  137  need not be superimposed with the receiver plate  185  interposed between them. For example, each of the rear air cell  184  and the front air cell  137  may include only one air bag or may be superimposed without the receiver plate  185 . Furthermore, they may include three or more air bags superimposed. 
   Embodiment 10 
     FIG. 49  is a perspective view showing a construction of a leg rest  198  of a chair-type massaging apparatus according to a tenth embodiment of the present invention. In description below, the leg rest  198  is illustrated as extended substantially downward from a front end of the seat surface  102   b , except for cases specifically mentioned. 
   The leg rest  198  of the tenth embodiment mainly comprises an upper unit  199   a , a lower unit  199   b , and an expansion and contraction system (distance changing device)  200 . The upper unit  199   a  mainly includes an upper support portion  201   a , a massaging portion  202   a , and an intermediate massaging portion  203   a . The lower unit  199   b  mainly includes a lower support portion  201   b , a massaging portion  202   b , and an intermediate massaging portion  203   b . A support portion of the present invention is constructed of the upper support portion  201   a  and the lower support portion  201   b.    
   The upper unit  199   a  is mounted in front of and under the seat surface  102   b  of the seat portion  102 , and the lower unit  199   b  is mounted under the upper unit  199   a . The upper and lower units  199   a  and  199   b  are mounted to be vertically arranged on the front side of the expansion and contraction system  200  mounted on a front side of an upper region of the seat portion  102   b  to be pivotable around a pivot  204 . As in the construction in which the lower leg massaging unit  178  described in the ninth embodiment is divided in two, the upper unit  199   a  and the lower unit  199   b  are vertically arranged to move toward and away from each other. 
   The upper unit  199   a  includes an upper support portion  201   a  which is of a substantially flat plate shape. The upper support portion  201   a  has an intermediate mounting surface  205   a  (trapezoid-shaped region defined by the two-dotted line of  FIG. 49 ) in an intermediate region substantially in a width direction thereof to allow the intermediate massaging portion  203   a  to be mounted thereon. Support surfaces  206   a  are provided on right and left sides outside the intermediate mounting surface  205   a  of the upper support portion  201   a  and configured to allow the right and left calves of the user to be supported thereon. Further, mounting surfaces  207   a  are formed outside the support surfaces  206   a  and configured to allow the massaging portion  202   a  to be mounted thereon. The intermediate mounting surface  205   a , the support surfaces  206   a , and the mounting surfaces  207   a  are parallel to each other, and the intermediate mounting surface  205   a  and the support surface  206   a  are configured to be as high as each other to form a flat surface, and the mounting surface  207   a  is configured to be lower than these. Thus, there are steps between the mounting surfaces  207   a  and the support surfaces  206   a.    
   Such a construction is exemplary. Alternatively, the mounting surfaces  207   a ,  207   b  and the support surfaces  206   a ,  206   b  may form a flat surface, or otherwise the intermediate mounting surfaces  205   a ,  205   b  and the support surfaces  206   a ,  206   b  may form a step between them in such a manner that the intermediate mounting surfaces  205   a ,  205   b  is lower than the support surface  206   a ,  206   b.    
   The rear air cells  208   a  are respectively mounted to the right and left mounting surfaces  207   a . The rear air cell  208   a  is configured to expand in fan-shaped form from a substantially flat state by inflowing the air thereto as in the rear air cell  135  and the front air cell  137  which have been described in the fourth embodiment. The rear air cell  208   a  has a main surface which is slightly smaller than the mounting surface  207   a . The rear air cell  208   a  is mounted on the mounting surface  207   a  as in the rear air cell  135  of the fourth embodiment in such a manner that its unexpandable end is oriented inward, i.e., toward the support surface  206   a , and its expandable end is oriented outward. 
   A receiver plate  209   a  is mounted in front of the rear air cell  208   a . The receiver plate  209   a  is of a substantially rectangular shape having an area slightly larger than that of the main surface of the rear air cell  208   a  and is placed in front of the rear air cell  208   a  so as to cover the entire of the rear air cell  208   a . The receiver plate  209   a  is mounted to the mounting surface  207   a  by a hinge  210   a  as in the receiver plate  136  of the fourth embodiment. Since the detail of the mounting structure is identical to the mounting structure of the receiver plate  136  of the fourth embodiment, it is not further described. As in the receiver plate  136  of the fourth embodiment, the receiver plates  209   a  and  209   b  which will be described later may be formed of a relatively hard material such as metal, or otherwise a relatively flexible material such as synthetic resin. 
   A front air cell  211   a  is mounted to a front surface of the receiver plate  209   a . A main surface portion of the front air cell  211   a  is of a substantially rectangular parallelepiped shape having an area substantially equal to that of an outer half region of the main surface of the receiver plate  209   a . The front air cell  211   a  is mounted to a substantially outer half region of the front surface of the receiver plate  209   a  as in the front air cell  137  of the fourth embodiment in such a manner that its unexpandable end is oriented inward and its expandable end is oriented outward. 
   In this manner, the massaging portion  202   a  is constructed of the rear air cell  208   a , the receiver plate  209   a , and the front air cell  211   a.    
   A pair of intermediate air cells  212   a  are mounted to be arranged on right and left sides on the intermediate mounting surface  205   a . As in the rear air cell  208   a  and the front air cell  211   a , each intermediate air cell  212   a  is configured to expand in fan-shaped form from a substantially flat state by inflowing the air thereto. The intermediate air cells  212   a  are mounted to the intermediate mounting surface  205   a  in such a manner that their expandable ends are closer to each other, their unexpandable ends are distant from each other, and a distance between them increases in a downward direction. As in the mounting structure by which the rear air cell  135  is mounted to the support surface  133  described in the fourth embodiment, each intermediate air cell  212   a  is mounted to the intermediate mounting surface  167  such that an expansion restricting portion is fixed to the intermediate mounting surface  205   a . The intermediate massaging portion  203   a  is constructed of the two intermediate air cells  212   a.    
   The intermediate air cells  212   a ,  212   b  are not intended to be limited to a configuration in which adjacent intermediate air cells  212   a ,  212   b  are tilted, but may be mounted to the intermediate mounting surfaces  205   a ,  205   b  to be arranged in parallel with each other. 
   The lower unit  199   b  mainly includes a lower support portion  201   b , a massaging portion  202   b  which is mounted to a mounting surface  207   b  of the lower support portion  201   b  and includes a rear air cell  208   b , a receiver plate  209   b  and a front air cell  211   b , and an intermediate mounting portion  203   b  which is mounted to an intermediate mounting surface  205   b  (trapezoid-shaped region defined by two-dotted line of  FIG. 30 ) of the lower support portion  201   b  and includes two intermediate air cells  212   b . The two intermediate air cells  212   b  are placed in such a manner that a distance between them is larger than that of the intermediate air cells  212   a  and increases in a downward direction and a tilting angle of the intermediate air cells  212   b  with respect to the longitudinal direction is equal to that of the intermediate air cells  212   a  so that the intermediate air cell  212   a  of the upper unit  199   a  and the intermediate air cell  212   b  of the lower unit  199   b  which are located on the same side extend in a straight line shape when the upper unit  199   a  and the lower unit  199   b  are moved closer to each other. The other construction of the lower unit  199   b  is identical to that of the upper unit  199   a , and will not be further described. 
   The upper unit  199   a  and the lower unit  199   b  are mounted to the expansion and contraction system  200  as shown in  FIG. 49  in such a manner that they are movable close to each other or away from each other. 
     FIGS. 50 to 53  are perspective views showing a construction of the expansion and contraction system  200 .  FIGS. 50 and 51  are views of the expansion and contraction system  200  in a most contracted state as seen from obliquely forward and obliquely rearward.  FIGS. 52 and 53  are views of the expansion and contraction system  200  in a most expanded state as seen from obliquely forward and obliquely rearward. As shown in  FIGS. 50 and 52 , the expansion and contraction system  200  mainly includes an upper element  213 , an intermediate element  214 , and a lower element  215 . The upper element  213  includes two tubes  216  that are rectangular in cross-section and are arranged to extend in a vertical direction in parallel with each other. Upper end portions of the tubes  216  are coupled to each other by a coupling element  217 . For the purpose of improved strength, a rod-shaped element  218  is provided to extend between intermediate regions of the two tubes  216 . 
   The coupling element  217  is bent to protrude forward at its intermediate region. A link at one end of an extensible arm  219  is pivotally mounted to a protruding portion  217   a  by a pivot extending forward and backward. The extensible arm  219  has a pantograph-type structure with three linked sections. 
   A mounting element  216   a  is fastened to a front side of an intermediate region of each tube  216 . Each mounting element  216   a  has a flat surface portion oriented forward, and the upper unit  199   a  is mounted to the flat surface portion (see  FIG. 49 ). 
   The pivot  204  extends horizontally outward from upper end portions of the tubes  216 . This enables the upper element  213  to be pivotable forward and backward with respect to the seat portion  102 . The pivot  204  is mounted to the seat portion  102 . The direct-acting type actuator  143  is pivotally attached at a tip end portion thereof to a pivot element (not shown) mounted at a rear portion of the expansion and contraction system  200 . By a user&#39;s predetermined input operation with the operation portion  147 , the leg rest  198  is automatically pivotable forward and backward. 
   The intermediate element  214  includes two slidable rods  220  that are longitudinally elongated rectangular in cross-section and are arranged in parallel with each other, and a horizontally elongated connecting rod  221  connecting lower ends of the slidable rods  220  to each other. The slidable rods  220  are inserted into the tubes  216 , respectively. Thereby, the slidable rods  220  are protrusible and retractable together, with respect to the tubes  216 . A longitudinally elongated nut  222  is fastened at a lower end thereof to an intermediate region in the rightward and leftward direction of the connecting rod  221 . A threaded rod  223  is threaded into the nut  222 , and an upper portion of the threaded rod  223  protrudes from an upper end of the nut  222 . 
   The threaded rod  223  is mounted to a rear side of the protruding portion  217   a  of the coupling element  217 , i.e., to a concave portion, to be rotatable around its axis. A motor  224  is mounted laterally relative to a position where the threaded rod  223  is mounted to the ee coupling element  217 . The motor  224  and the threaded rod  223  are coupled to each other by a rotation transmission system  224   a  including a belt and pulleys. Thereby, a rotation of an output shaft of the motor  224  is transmitted to the threaded rod  223 , which is thereby protrusible and retractable with respect to the nut  222 . 
   The nut  222  has an outer shape of a rod having a rectangular cross-section. A link formed by crossing two link members at an intermediate position of the extensible arm  219  is pivotally mounted to an intermediate region in a longitudinal direction of the nut  222  by a pivot extending forward and backward. In this construction, by driving the motor  224 , the intermediate element  214  moves up and down, causing the extensible arm  219  to expand and contract. 
   A cut-out portion  216   b  that is vertically elongate is provided to extend in each of opposing surfaces, i.e., inner surfaces of the tubes  216  in a range from lower end thereof to an intermediate region thereof. A connecting plate  220   a  extends from an intermediate region in the longitudinal direction of each slidable rod  220  inward, i.e., toward the opposite slidable rod  220 . A guide  225  is mounted on the connecting plate  220   a  and is configured to have a circular hole extending in parallel with the slidable rod  220 . The connecting plate  220   a  extends from the inner side to the outer side of the tube  216  through the cut-out portion  216   b . This allows the slidable rod  220  to advance and retract into and from the tube  216  without any interference between the connecting plate  220   a  and the tube  216 . In this manner, the slidable rod  220 , the connecting plate  220   a , and the guide  225  are movable up and down. 
   The lower element  215  mainly includes two slidable rods  226  and two mounting elements  227 . Each slidable rod  226  is of a round rod shape with a diameter slightly smaller than that of the circular hole formed in the guide  225 . Lower ends of the slidable rods  226  are coupled to each other by a horizontally elongate coupling element  226   a . A mounting element  227  is mounted to a lower end portion of each slidable rod  226 . Each mounting element  227  has a flat surface portion oriented forward. The lower unit  199   b  is mounted to the flat surface portion (see  FIG. 49 ). 
   Upper ends of the mounting elements  227  are coupled to each other by a horizontally elongate coupling element  227   a . A link at a lower end of the extensible arm  219  is pivotally mounted to the coupling plate  227   a  by a pivot extending forward and backward. The motor  224  drives the intermediate element  214 , which thereby moves toward and away from the upper element  213 . When the extensible arm  219  expands and contracts, the lower element  215  slides close to and away from the intermediate element  214 , causing the expansion and contraction system  200  to entirely expand and contract. 
   In the above mentioned construction, the leg rest  198  is pivotable forward and backward around the pivot  204 . In addition, by changing the distance between the upper unit  199   a  and the lower unit  199   b , the leg rest  198  is expandable and contractable. By causing the leg rest  198  to expand and contract, the upper unit  199   a  is moved to a position at which the upper unit  199   a  supports an upper side of the lower leg of the user and the lower unit  199   b  is moved to a position at which the lower unit  199   b  supports a lower side of the lower leg of the user. 
   Since the intermediate air cells  212   a  and  212   b  are mounted to the support portion  165  such that the distance between the air cells  212   a  and the distance between the air cells  212   b  respectively increase downward, they contact a larger range in the longitudinal direction of the lower legs of the user. As a result, the intermediate air cells  212   a  and  212   b  contacting only a longitudinal part of the calves is avoided. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus of the tenth embodiment are identical to those of the chair-type massaging apparatus  101  of the fourth embodiment, the same components are identified by the same reference numerals, their configurations, functions, and effects will not be further described. 
   It shall be understood that the upper unit  199   a  and the lower unit  199   b  are not intended to be limited to the above mentioned configurations, but may be constructed such that any of the leg rests of the fourth to ninth embodiments is divided in two in the vertical direction. As in the fourth embodiment, the number and size of the rear air cells  208   a ,  208   b , the receiver plates  209   a ,  209   b , and the front air cells  211   a ,  211   b  are not intended to be limited to those illustrated in the tenth embodiment. Also, the rear air cell  208   a ,  208   b  and the front air cell  211   a ,  211   b  need not be superimposed with the receiver plate  209   a ,  209   b  interposed between them. For example, each of the rear air cell  208   a ,  208   b  and the front air cell  211   a ,  211   b  may include only one air bag or may be superimposed without the receiver plate  209   a ,  209   b . Furthermore, they may include three or more air bags superimposed. 
   Embodiment 11 
     FIG. 54  is a perspective view showing a construction of an entire chair-type massaging apparatus according to an eleventh embodiment of the present invention. As shown in  FIG. 54 , a chair-type massaging apparatus  301  of this embodiment is constructed such that the leg rest  104  of the chair-type massaging apparatus of the fourth embodiment is replaced by a leg rest  304  described below. 
   The leg rest  304  is provided with a longitudinally elongate support protrusion  331  formed at a substantially intermediate region in a width direction of a front surface thereof, and is configured to support the calves of the legs of the user on regions of the front surface which are located on both sides of the protrusion  331 . As described later, the leg rest  304  is provided with a plurality of air cells which are connected by air hoses to the air inflow and outflow device  109  including a pump, a valve, and other components, which is built in the seat portion  102  or the back rest  103 . The air cells expand and contract by air inflow and outflow by the air inflow and outflow device  109 . With the user seated, the air cells expand and contract repeatedly, applying a pressing stimulation to the lower legs of the user. 
   A construction of the leg rest  304  will be described in detail. For the sake of simple explanation, as described below, the leg rest  304  is illustrated as extended substantially downward from a front end of the seat surface  102   b , except for the condition specifically described.  FIG. 55  is a front view showing the construction of the leg rest  304  provided in the chair-type massaging apparatus  301  according to the eleventh embodiment of the present invention.  FIGS. 56 and 57  are plan views thereof. As shown in  FIGS. 55 to 57 , the leg rest  304  of this embodiment mainly includes a support portion  332  and massaging portions  333 . The support portion  332  is configured such that the longitudinally elongate support protrusion  331  protrudes from the substantially intermediate region in the width direction of the front surface of a flat plate oriented such that its longitudinal direction corresponds with the vertical direction. The support portion  332  is mounted at an upper end thereof to a front side of the upper portion of the seat portion  102  by a pivot extending horizontally (see  FIG. 54 ). 
   As shown in  FIGS. 55 to 57 , support surfaces  334  are located on both sides outside the support protrusion  331  of the support portion  332  and configured to support the right and left calves of the user. Mounting surfaces  335  are provided outside the support surfaces  334  and configured to allow the massaging portions  333  each including rear air cells  336 , receiver plates  337 , and front air cells  338  to be mounted thereon. Since rear air cell  336  and the front air cell  338  are configured as in the rear air cell  135  and the front air cell  137  described in the fourth embodiment, and the construction and the rotating structure of the receiver plate  337  are identical to those of the receiver plate  136  described in the fourth embodiment, these will not be further described. The support surface  334  and the mounting surface  335  are parallel to each other, and the mounting surface  335  is lower than the support surface  334 . Thus, there is a step between the mounting surface  335  and the support surface  34 . 
   While in the eleventh embodiment, the mounting surface  335  is formed lower than the support surface  334  to form a step between them, they may alternatively form a flat surface. 
   The support protrusion  331  is made of urethane foam, sponge material, foamed polystyrene, low-repulsion urethane, or chip urethane. The support protrusion  331  is provided on an intermediate region of the front surface of the support portion  332  to extend over an entire length in the vertical direction thereof and to protrude slightly forward from the support surface  334 . The protruding amount is sufficiently small for the thickness of the lower legs of the user with a standard frame. With the lower legs of the user placed on the leg rest  304 , both lateral end portions of the support protrusion  331  are in contact with rear inner regions of the lower legs, i.e., inner regions of the calves. In contrast to an intermediate wall or a side wall of the leg rest of a conventional massaging apparatus, the height of the support protrusion  331  is sufficiently small. This makes it possible for the user to assume a desired posture by merely moving the lower legs slightly away from the support surface  334  and by crossing them when the user desires to cross the legs. The support protrusion  331  is shaped to have a width that increases in a downward direction. 
   Depending on the use status of the leg rest  304 , the lower legs of the user may be supported only by the support surface  334 , or otherwise, only a part of the calves may be supported on the support surface  334  and the remaining part may be supported by the support protrusion  331 . 
   The support protrusion  331  may be made of materials other than the urethane foam, the sponge, the foamed polystyrene, the low-repulsion urethane, or the chip urethane. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus  301  of the eleventh embodiment are identical to those of the chair-type massaging apparatus  101  of the fourth embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   In such a configuration, while the chair-type massaging apparatus  301  is not used, the rear air cells  336  and the front air cells  338  contract as shown in  FIG. 56 , so that the front side of the massaging portion  333  forms a substantially flat surface with the protrusion present only in the intermediate region in the width direction. Therefore, the leg rest  304  forms a substantially flat plate shape and the chair-type massaging apparatus  301  has a simple external appearance. 
   With the user seated on the chair-type massaging apparatus  301  in such a state, the lower legs of the user are easily placed on the leg rest  304  because the front surface of the leg rest  304  forms a substantially flat surface except for the intermediate region in the width direction thereof, and the leg rest  304  opens forward and laterally. In addition, by causing the inner regions of the calves to contact the support protrusion  331  with the lower legs of the user placed on the support portion  332 , the calves of the user are guided to a massage position on the support surface  334 . Furthermore, when the lower legs are not massaged, or the chair-type massaging apparatus  301  is otherwise used as an easy chair, for example, the user assumes a posture of crossed legs, the user can assume a desired posture freely without being disturbed by the support protrusion  331 , because the height of the support protrusion  331  is sufficiently small in contrast to the intermediate wall or the like provided on the leg rest of the conventional massaging apparatus. 
   Since the support protrusion  331  is configured to have the width that increases in a downward direction, the lower legs of the user are easily fitted to the support protrusion  331 , and the support protrusion  331  contacting only a longitudinal part of the calves is avoided. 
   The number and size of the support protrusion  331  are not intended to be limited to the configuration of the eleventh embodiment. For example, a plurality of support protrusions may be arranged in the vertical direction. 
   Embodiment 12 
     FIG. 58  is a front view showing a construction of a leg rest of a chair-type massaging apparatus according to a twelfth embodiment of the present invention.  FIGS. 59 and 60  are plan views thereof.  FIG. 61  is a partially enlarged plan view of the leg rest. As shown in  FIGS. 58 to 60 , each massaging portion  352  of a leg rest  351  of the twelfth embodiment is constructed such that two pressing heads (massaging elements)  353  are arranged in the longitudinal direction on the front side of each front air cell  338 . More specifically, as shown in  FIG. 61 , a pressing plate  354  having a main surface of a shape substantially identical to that of the front surface of the front air cell  338  is fixed to the front surface of the front air cell  338 , and the two pressing heads  353  are arranged in the vertical direction on the front surface of each pressing plate  354 . When the rear air cell  336  and the front air cell  338  expand, the pressing heads  353  press the outer region of the shin of the user, thus applying stimulation to the user as if the user was being massaged by a masseuse. 
   The pressing heads  353  may be made of metal or synthetic resin, and are desirably made of elastic elastomer, various kinds of urethane foams, or other foams, in order to inhibit strong stimulation from being applied to the user. Also, the shape of the pressing heads  353  is not intended to be limited, and is desirably pointless, for example, hemispherical. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus of the twelfth embodiment are identical to those of the chair-type massaging apparatus  301  of the eleventh embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   As in the fourth embodiment, the number and size of the rear air cells  336 , the receiver plates  337  and the front air cells  338  are not intended to be limited to those illustrated in the twelfth embodiment. Also, the rear air cell  336  and the front air cell  338  need not be superimposed with the receiver plate  337  interposed between them. For example, each of the rear air cell  336  and the front air cell  338  may include only one air bag or may be superimposed without the receiver plate  337 . Furthermore, they may include three or more air bags superimposed. 
   As in the eleventh embodiment, the number and size of the support protrusion  331  are not intended to be limited to the configuration of the eleventh embodiment, and for example, a plurality of support protrusions may be arranged in the vertical direction. 
   Embodiment 13 
     FIG. 62  is a front view showing a construction of a leg rest of a chair-type massaging apparatus according to a thirteenth embodiment of the present invention.  FIGS. 63 and 64  are plan views thereof. As shown in  FIGS. 62 to 64 , a receiver plate  363  included in a massaging portion  362  of a leg rest  361  according to the thirteenth embodiment is structured such that an outer end portion in the width direction thereof is bent forward a predetermined angle. A front air cell  338  is mounted to a region of the receiver plate  363  which is located outside the bent position. As shown in  FIG. 64 , a rear air cell  336  is expandable to an extent to which a base end portion of the receiver plate  363  becomes vertical to a support surface  334 . So, when the rear air cell  336  expands, the support surface  334  is covered with an outer end portion of the receiver plate  363  from the front. The receiver plate  363  may be made of any materials so long as the receiver plate has hardness sufficient to maintain the bent state. The receiver plate is preferably made of materials having relatively high hardness such as metals, plastic or other materials having high strength and rigidity at temperatures around a room temperature. 
   In contrast to the configuration in which the receiver plate is flat, the front air cell  338  is moved closer to the lower leg of the user when the rear air cell  336  expands. By expanding the front air cell  338 , the front region of the lower leg including the outer region of the shin of the user is pressed substantially rearward, thus applying stronger stimulation to the outer region of the shin. Even when the front air cell  338  is smaller, sufficient strength of massage is ensured. 
   While the receiver plate  363  is bent forward at one point, it may alternatively be entirely curved in a circular arc shape. 
   Since the other configurations, functions, and effects of the chair-type massaging apparatus of the thirteenth embodiment are identical to those of the chair-type massaging apparatus  301  of the eleventh embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   As in the fourth embodiment, the number and size of the rear air cells  336 , the receiver plates  337  and the front air cells  338  are not intended to be limited to those illustrated in the thirteenth embodiment. Also, two or more air bags may be superimposed on the front surface of the receiver plate  363  or behind it. 
   As in the eleventh embodiment, the number and size of the support protrusion  331  are not intended to be limited to those of the thirteenth embodiment. For example, a plurality of support protrusions may be arranged in the vertical direction. 
   Embodiment 14 
     FIG. 65  is a front view showing a construction of a leg rest  371  of a chair-type massaging apparatus according to a fourteenth embodiment of the present invention.  FIG. 66  is a side view thereof. As shown in  FIGS. 65 and 66 , the leg rest  371  according to the fourteenth embodiment includes a lower leg massaging unit  372  configured to massage the lower leg of the user, i.e., a region ranging from a knee to an ankle of the user, and a foot massaging unit  373  configured to massage a foot of the user, i.e., a region ranging from the ankle to a tip portion of the foot. The lower leg massaging unit  372  is identical in construction to that of the leg rest  304  of the eleventh embodiment except that each of the right and left massaging portions  374  includes rear air cells  375  and receiver plates  376  which are arranged in the vertical direction in such a manner that the rear air cell  336  and the receiver plate  337  of the massaging portion  333  shown in  FIG. 11  are each divided in two in the vertical direction. 
   Subsequently, a construction of the massaging portion  374  will be described in detail. The two rear air cells  375  are arranged in the vertical direction on each mounting surface  335 . As in the rear air cell  135  and the front air cell  137  of the fourth embodiment, each rear air cell  375  is configured to expand in fan-shaped form from a substantially flat state by inflowing the air thereto. The rear air cell  375  has a main surface portion which is slightly smaller than an upper half region (or lower half region) of the mounting surface  335 , and is placed on the mounting surface  335  as in the rear air cell  135  of the fourth embodiment in such a manner that its unexpandable end is oriented inward, i.e., toward the support surface  334 , and its expandable end is oriented outward. 
   The receiver plate  376  is mounted in front of each rear air cell  375 . Each receiver plate  376  is of a substantially rectangular plate shape having an area slightly larger than that of a main surface portion of the rear air cell  375 , and is mounted in front of the rear air cell  375  to entirely cover the rear air cell  375 . The receiver plate  376  is mounted on the mounting surface  335  by a hinge  377  as in the receiver plate  136  of the fourth embodiment, as in the mounting structure of the receiver plate  136  of the fourth embodiment. One front air cell  338  is mounted on an outer half region of the front surface of each receiver plate  376  as in the fourth embodiment. As in the receiver plate  136  of the fourth embodiment, the receiver plate  376  may be made of a relatively hard material such as metal, or a relatively flexible material such as synthetic resin. 
   In the manner described above, the rear air cells  375 , the receiver plates  376 , and the front air cells  338  form the massaging portion  374 . 
   Each foot massaging unit  373  includes a sole support portion  378  of a substantially flat plate shape, and a sole massaging portion  383  comprised of air cells  379  to  382  and a vibrator (not shown). As in the rear air cells  336  and the front air cells  338 , the air cells  379  to  382  expand in fan-shaped form from a substantially flat state by inflowing the air thereto. The sole support portion  378  has an intermediate mounting surface  384  in an intermediate region in a width direction thereof to allow the air cells  379  and the vibrator to be mounted thereon. Support surfaces  385  are provided on right and left sides outside the intermediate mounting surface  384  of the sole support portion  378  and configured to allow the sole of the foot of the user to be supported thereon. Mounting surfaces  386  are provided on outer end portions of an upper surface of the sole support portion  378  to be located on right and left sides outside the support surface  385  and configured to allow air cells  380  and  381  to be mounted thereon. The intermediate mounting surface  384 , the support surfaces  385  and the mounting surfaces  386  are parallel to each other. The intermediate mounting surface  384  is formed lower than the support surface  385 , and the mounting surface  386  is formed lower than the intermediate mounting surface  384 . Thus, there are step portions between the intermediate mounting surface  384  and the support surface  385  and between the mounting surface  386  and the support surface  385 . 
   The support surface  385  and the intermediate mounting surface  384  may form a flat surface or otherwise the support surface  385  and the mounting surface  386  may form a flat surface. 
   The pair of air cells  379  are mounted to a front half region of the intermediate mounting surface  384  to be arranged on the right and left sides. The air cells  379  are mounted to the intermediate mounting surface  384  in such a manner that their expandable ends are close to each other and their unexpandable ends are distant from each other. 
   The vibrators are mounted to the intermediate mounting surface  384  to be located behind the two air cells  379 . Each vibrator is positioned to correspond to an arch of a foot of the user with a standard frame placed on the foot massaging unit  373 . 
   The air cell  380  is mounted on a front half region of the mounting surface  386  and positioned laterally of the air cell  379 . The air cell  380  has a main surface that is slightly smaller than the front half region of the mounting surface  386 , and is placed such that its unexpandable end is oriented inward. A receiver plate  387  having a main surface of substantially the same shape as an upper surface of the air cell  380  is mounted on the upper surface of the air cell  380 . Further, the air cell  382  is mounted on an upper surface of the receiver plate  387 . Since the arrangement and configuration of the air cells  380  and  382  and the receiver plate  387  are identical to those of the rear air cell  135 , the receiver plate  136 , and the front air cell  137  described in the fourth embodiment, they will not be further described. 
   The air cell  381  is mounted on a rear half region of the mounting surface  386  and positioned laterally of the vibrator. The air cell  381  is smaller in size than the air cell  380 , and is placed such that its unexpandable end is oriented inward as in the air cell  380 . 
     FIG. 67  is a front view showing a construction of the leg rest  371  with the air cells  379  to  382  expanded, and  FIG. 68  is a side view thereof. With the sole of an adult user with a standard frame placed on the foot massaging unit  373 , a part of the sole is placed on the support surface  385  and a remaining part is placed on the air cell  379  and the vibrator. Under this condition, by expanding the air cells  380  and  382 , a top surface of the foot of the user is pressed from above by the air cell  382  as shown in  FIGS. 67 and 68 . Thus, the top surface of the foot of the user is massaged. In addition, when the air cells  379  and  381  or the vibrator operate with the foot of the user pressed from above, the foot of the user is inhibited from disengaging by the pressing force or the vibration. 
   By expanding the air cell  379 , the tip portion of the foot is pressed over a range from a bottom region to an inner region. By expanding the air cell  381 , ankle (malleolus) of the user is pressed. By operating the vibrator, vibrational stimulation is applied to the top surface of the foot of the user. 
   By repeating expansion and contraction of the air cells  379  to  382  independently or in synchronization with each other, or by operating the vibrator independently or in synchronization with these air cells  379  to  382 , comfortable stimulation is applied to the user while the foot is massaged. 
   As shown by two-dotted line in  FIGS. 65 to 68 , the lower leg massaging unit  372  and the foot massaging unit  373  may be coupled by a frame  388  to configure the leg rest  371 . In this case, the frame  388  may be provided with an expansion and contraction system to vary a distance between the lower leg massaging unit  372  and the foot massaging unit  373 . Alternatively, instead of coupling the lower leg massaging unit  372  to the foot massaging unit  373  by the frame  388  or other element, only the lower leg massaging unit  372  may be pivotally mounted on the seat portion  102 , and the foot massaging unit  373  may be placed on a floor surface under the lower leg massaging unit  372  during use. 
   The above mentioned configuration of the lower leg massaging unit  372  is merely exemplary, and may be configured as in the leg rest of any of the eleventh to thirteenth embodiments. In addition, the above mentioned configuration of the foot massaging unit  373  is merely exemplary, and the foot massaging unit  373  may alternatively be configured in such a manner that the air cells  380  and  382  and the receiver plate  387  may be omitted, and/or one or a plurality of the air cells  379  and  381  and the vibrator may be omitted, other air bags or vibrators may be provided separately from the air cells  379  to  382  and the vibrator, or otherwise one or a plurality of the air cells  379  to  382  and the vibrator may be placed at positions different from those mentioned above. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus of the fourteenth embodiment are identical to those of the chair-type massaging apparatus  301  of the eleventh embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   As in the fourth embodiment, the number and size of the rear air cells  375 , the receiver plates  376  and the front air cells  338  are not intended to be limited to those illustrated in the fourteenth embodiment. Also, the rear air cell  375 , the receiver plate  376 , and the front air cell  338  need not be superimposed with the receiver plate  376  interposed between them. For example, each of the rear air cell  375  and the front air cell  338  may include only one air bag or may be superimposed without the receiver plate  376 . Furthermore, they may include three or more air bags superimposed. 
   Embodiment 15 
     FIG. 69  is a perspective view showing a construction of a chair-type massaging apparatus according to a fifteenth embodiment of the present invention. As described below, for the simplicity of explanation, a leg rest  391  is illustrated as extended substantially downward from a front end of a seat surface  102   b , except for a case specifically described. 
   The leg rest  391  of the fifteenth embodiment mainly includes an upper unit  392 , a lower unit  393 , and an expansion and contraction system (distance changing device)  200 . The upper unit  392  includes an upper support portion  395 , massaging portions  396 , and a support protrusion  397 . The lower unit  393  mainly includes lower support portion  398 , massaging portions  399  and a support protrusion  400 . A support portion of the present invention is constructed of the upper support portion  395  and the lower support portion  398 . 
   The upper unit  392  is positioned in front of and under the seat surface  102   b  of the seat portion  102 , and the lower unit  393  is positioned under the upper unit  392 . The upper unit  392  and the lower unit  393  are mounted to be arranged in the vertical direction on a front side of the expansion and contraction system  200  mounted to a front side of an upper portion of the seat portion  102  to be rotatable around a pivot  204 . In other words, as in the configuration in which the lower leg massaging unit  372  of the fourteenth embodiment is divided in two in the vertical direction, the upper unit  392  and the lower unit  393  are arranged in the vertical direction such that they move toward and away from each other. 
   The upper support portion  395  of the upper unit  392  is of a substantially plate shape. The upper support portion  395  is structured such that the support protrusion  397  protrudes forward from a substantially intermediate region in the width direction thereof. Support surfaces  402  are provided on right and left sides outside the support protrusion  397  of the upper support portion  395  and configured to allow the right and left calves of the legs of the user to be supported thereon. Mounting surfaces  403  are provided outside the support surfaces  402  and configured to allow the massaging portion  396  to be mounted thereon. The support surface  402  and the mounting surface  403  are parallel to each other, and the mounting surface  403  is formed lower than the support surface  402 . Thus, there is a step between the mounting surface  403  and the support surface  402 . 
   Alternatively, the mounting surfaces  403 ,  405  and the respective support surface  402 ,  404  may form respective flat surfaces. 
   A rear air cell  406  is mounted to each of the right and left mounting surfaces  403 . The rear air cell  406  expands in fan-shaped form from a substantially flat state by inflowing air thereto as in the rear air cell  135  and the front air cell  137  described in the fourth embodiment. The rear air cell  406  has a main surface portion which is slightly smaller than the mounting surface  403 , and is fixed on the mounting surface  403  as in the rear air cell  135  of the fourth embodiment in such a manner that its unexpandable end is oriented inward, i.e., toward the support surface  402 , and its expandable end is oriented outward. 
   The receiver plate  407  is mounted in front of the rear air cell  406 . The receiver plate  407  has a substantially rectangular plate shape having an area slightly larger than that of a main surface portion of the rear air cell  406 , and is mounted in front of the rear air cell  406  to entirely cover the rear air cell  406 . The receiver plate  407  is mounted on the mounting surface  403  by a hinge  408  as in the receiver plate  136  of the fourth embodiment, which will not be further described. As in the receiver plate  136  of the fourth embodiment, the receiver plate  407  and a receiver plate  411  described later may be made of a relatively hard material such as metal, or a relatively flexible material such as synthetic resin. 
   A front air cell  409  is mounted to a front surface of the receiver plate  407 . A main surface portion of the front air cell  409  is of a substantially rectangular shape having an area substantially equal to that of an outer half region of the main surface of the receiver plate  407 . The front air cell  409  is mounted to a substantially outer half region of the front surface of the receiver plat  407  as in the front air cell  137  of the fourth embodiment in such a manner that its unexpandable end is oriented inward and its expandable end is oriented outward. 
   In the manner described above, the massaging portion  396  is constructed of the rear air cell  406 , the receiver plate  407 , and the front air cell  409 . 
   The support protrusion  397  is formed to have a width between both lateral ends thereof that increases in a downward direction. While the support protrusion  397  is formed to have a width that increases in a downward direction, it may alternatively be structured such that the both lateral ends are parallel to each other to form a substantially rectangular shape in a front view. 
   The lower unit  393  mainly includes a lower support portion  398 , and a massaging portion  399  that is mounted to the mounting surface  405  of the lower support portion  398  and is comprised of a rear air cell  410 , a receiver plate  411 , and a front air cell  412 . A support protrusion  400  protrudes forward from a substantially intermediate region in the width direction of the lower support portion  398  to have a width that increases in a downward direction. The support protrusion  400  is configured in such a manner that the width thereof is larger than that of the support protrusion  397  and increases in a downward direction, and tilting angles of the lateral ends of the support protrusion  400  with respect to the longitudinal direction are equal to those of the support protrusion  397  so that the ends of the protrusions  397  and  400  which are located on the same side extend in a straight line shape when the upper unit  392  and the lower unit  393  are moved close to each other. Support surfaces  404  are provided on right and left sides outside the support protrusion  400  of the lower support portion  398  and configured to allow the right and left calves of the user to be supported thereon. Since the other configuration of the lower unit  393  is identical to that of the upper unit  392 , it will not be further described. 
   The above constructed upper unit  392  and lower unit  393  are mounted to the expansion and contraction system  200  described in the tenth embodiment in such a manner that they are relatively movable toward and away from each other. Since the configurations, functions, and effects of the expansion and contraction system  200  are identical to those described in the tenth embodiment, the same reference numerals are used to designate the same or corresponding parts, which will not be further described. 
   With the above mentioned configuration, the leg rest  391  is pivotable forward and backward around the pivot  204 , and is contractable by changing the distance between the upper unit  392  and the lower unit  393 . By thus expanding and contracting the leg rest  391 , the upper unit  392  is moved to a position where the upper unit  392  supports the upper portion of the lower leg of the user and the lower unit  393  is moved to a position where the lower unit  393  supports the lower portion of the lower leg, independent of the specific frame of the user. 
   Since the support protrusions  397  and  400  are configured to have the widths that increase downward, they contact a longitudinally larger region of the lower legs of the user. As a result, the support protrusions  397  and  400  contacting only a longitudinal part of the calves of the user is avoided. 
   Since other configurations, functions, and effects of the chair-type massaging apparatus of the fifteenth embodiment are identical to those of the chair-type massaging apparatus  301  of the eleventh embodiment, the same components are identified by the same reference numerals and their configurations, functions, and effects will not be further described. 
   The configurations of the upper unit  392  and the lower unit  393  are not intended to be limited to the above, and the leg rest of any of the eleventh to fourteenth embodiments may be divided in two in the vertical direction. As in the fourth embodiment, the number and size of the rear air cells  406 ,  410 , the receiver plates  407 ,  411  and the front air cells  409 ,  412  are not intended to be limited to those illustrated in the fifteenth embodiment. Also, the rear air cells  406 ,  410  and the front air cells  409 ,  412  need not be superimposed with the respective receiver plate  407 ,  411  interposed between them. For example, each of the rear air cells  406 ,  410  and the front air cells  409 ,  412  may include only one air bag or may be superimposed without a corresponding receiver plate  407 ,  411 . Furthermore, they may include three or more air bags superimposed. 
   Embodiment 16 
     FIG. 70  is a perspective view of a massaging apparatus with a massaging apparatus cover  501  attached thereover according to a sixteenth embodiment of the present invention. The massaging apparatus comprises a chair body  505  including a seat portion  502  in which the user is seated, a back rest  503  on which a back of the user is supported, a leg rest  504  on which legs are placed, and right and left arm rests  510 . 
   The cover  501  is attached over the chair-type massaging apparatus. The cover  501  includes a back rest cover  506  that covers the back rest  503 , and a lower cover  507  that is separable from the back rest cover  506 , and covers the seat portion  502  and the leg rest  504 . Alternatively, a separate leg rest cover may be configured to cover only the leg rest  504 , instead of an integral cover that covers the seat portion  502  and the leg rest  504 . 
   A mounted state of the cover  501  will be described. The back rest cover  506  covers substantially the entire surface of the back rest  503  on which the body of the user is placed, and its upper end portion and both side end portions are folded backward with respect to the back rest  503 . The back rest cover  506  is fixed to a back surface of the back rest  503  by fasteners at the folded end portions. A region of the lower cover  507  that covers the seat portion  502  is fixed to the seat portion  502  by tape fasteners at a peripheral region of the seat portion  502 . 
   A region of the lower cover  507  that covers the leg rest  504  functions as the cover for the leg rest  504 . As shown in the cross-sectional view of  FIG. 71 , right and left end portions  530  are folded back and located on the rear side. Upper and lower peripheral regions of the both end portions  530  and upper and lower peripheral regions of a front portion of an intermediate foldable portion  509  which are opposed to the upper and lower peripheral regions of the both end portions  530  are stitched up together. Thereby, pocket-shaped bag portions  532  are formed on right and left end portions of the intermediate foldable portion  509  (see  FIG. 71 ). Each of the right and left bag portions  532  has an opening that opens inward in the rightward and leftward direction on the rear surface side of the intermediate foldable portion  509 . A protrusible plate  513 , an upper air cell  515 , a receiver plate  522 , and a pressing element  523  are inserted into the bag portion  532  through the opening. The protrusible plate  513  is able to rise up inward in the rightward and leftward direction as described later, and in this state, the above elements are inserted into the bag portion  532 . After the insertion, by lowering and retracting the protrusible plate  513  outward in the rightward and leftward direction, each of the end portions  530  is sandwiched between the lower air cell  514  and the protrusible plate  513 . In this manner, the region of the lower cover  507  that covers the leg rest  504  is attached to the leg rest  504  without using means such as the fasteners. Since the bag portion  532  accommodates the protrusible plate  513  and other elements, the lower cover  507  is configured not to disengage from the leg rest  504 . Thereby, a leg rest cover that is easily removably attachable is achieved. 
   The cover  501  is configured such that the back rest cover  506  and the lower cover  507  are respectively removable. 
   An arch-shaped hand accommodating portion  510   a  is provided on a front portion of each of the arm rests  510  on right and left sides of the chair-type massaging apparatus to allow a palm or other portion of a hand to be inserted into the accommodating portion  510   a . A massaging system such as air cells (not shown) is provided on an inner surface of the hand accommodating portion  510   a  to allow the hand to be massaged. 
   As shown in  FIG. 79 , the leg rest  504  of the chair body  505  includes a support surface  518  on which the right and left legs of the user are supported with the user seated on the chair body  505 , and a protrusible and retractable system  508  configured to protrude and retract toward the legs within the support surface  518 .  FIG. 79  is a plan view of the protrusible and retractable system  508 , in which the air cells are in an unexpanded (retracted) state and  FIG. 80  is a plan view of the protrusible and retractable system  508 , in which all the air cells are in expanded (protruded) state.  FIG. 78  is a front view of the protrusible and retractable system  508 . 
   As shown in  FIGS. 79 and 80 , the protrusible and retractable system  508  includes intermediate air cells  511  located at an intermediate region in the rightward and leftward direction of the protrusible and retractable system  508 , and right and left air cells  512  located at both peripheral regions in the rightward and leftward direction. Each of the right and left air cells  512  includes the lower air cell  514  placed under (on a rear surface side of) the protrusible plate  513  and the upper air cell  515  placed on (on a front surface side) of the protrusible plate  513 . The legs of the user are massaged with each of the legs placed between the intermediate air cell  511  and the air cells  512 . In  FIGS. 79 and 80 , the contours of the right and left legs  517  are indicated by broken lines. 
   As shown in  FIGS. 78 to 80 , a hinge  520  is mounted on an inner side in the rightward and leftward direction of the protrusible plate  513 , and the protrusible plate  513  is mounted to a base  516  by the hinge  520 . The hinge  520  enables the protrusible plate  513  to rise up inward in the rightward and leftward direction. A torsion spring  521  is mounted to the hinge  520 . The torsion spring  521  causes the protrusible plate  513  to be biased outward in the rightward and leftward direction. Therefore, in a state in which no external force is applied by the air cells, the protrusible plates  513  retracts as shown in  FIG. 79 . 
   A receiver plate  522  is mounted on an upper side (front side) of the protrusible plate  513  by a hinge  520 . The hinge  520  is positioned on inner side in the rightward and leftward direction of the receiver plate  522 . Thereby, the receiver plate  522  is able to fall inward in the rightward and leftward direction. A torsion spring  521  causes the protrusible plate  513  to be biased outward in the rightward and leftward direction. Therefore, in a state in which no external force is applied by the air cells, the protrusible plate  513  retracts as shown in  FIG. 79 . As should be appreciated, the support surface  518  on which the legs of the user are supported, and the protrusible and retractable system  508  are substantially flat in a retracted state. 
   All the air cells  511 ,  514 , and  515  have a fan-shaped form in cross-section and expand in a fan-shaped form as shown in  FIG. 80 . 
   As shown in a front view of  FIG. 78 , the two intermediate air cells  511  have a substantially rectangular shape that is vertically elongated as seen in a plan view, and are placed to be symmetric in the rightward and leftward direction. As shown in  FIG. 80 , the intermediate air cells  511  are placed such that centers of the fan-shaped forms in cross-section are oriented outward in the rightward and leftward direction. With the intermediate air cells  511  expanded, they protrude outward in the rightward and leftward direction. 
   Right and left lower air cells  514  are each placed between each of right and left peripheral regions of the base  516  and the protrusible plate  513 , and are placed in such a manner that centers of the fan-shaped forms are oriented inward as shown in  FIG. 80 . When the lower air cells  514  expand, they protrude inward in the rightward and leftward direction so as to press the protrusible plates  513  from rearward, causing the protrusible plate  513  to rise up inward in the rightward and leftward direction. When the upper air cell  515  further expands, the upper air cell  515  presses the receiver plate  522  from rearward, causing the receiver plates  522  to fall inward in the rightward and leftward direction. A pressing element  523  that protrudes in a substantially hemispherical shape is mounted on a front side of the receiver plate  522 . Right and left legs  517  are each sandwiched between the pressing element  523  and the intermediate air cell  511  and massaged. Since the center of the fan-shaped form of the upper air cell  515  is oriented toward the hinge  520  by which the receiver plate  522  is mounted, the receiver plate  522  is pressed efficiently by the expansion of the upper air cell  515  in fan-shaped form. 
   As shown in  FIG. 78 , each upper air cell  515  is divided in two in the vertical direction to include a calf air cell  515   a  and an ankle air cell  515   b , which are independently protrusible and retractable. In the front view of  FIG. 78 , the receiver plates  522 , the pressing elements  523 , and other elements are appropriately omitted. 
   As described above, the leg rest  504  of the chair body  505  is provided with the protrusible and retractable system  508  which is covered with the lower cover  507  of the cover  501 .  FIG. 71  is a cross-sectional view showing a state in which the lower cover  507  covers the protrusible and retractable system  508 . As shown in  FIG. 71 , the lower cover  507  includes an intermediate foldable portion  509  in an intermediate region in the rightward and leftward direction, which is expandable according to protrusion (expansion) of the intermediate air cells  511 . 
     FIG. 72(   a ) is an enlarged cross-sectional view of the intermediate foldable portion  509  in a folded state with the protrusible and retractable system  508  retracted. As shown in  FIG. 72(   a ), the intermediate foldable portion  509  includes first and second surface portions  509   a  and  509   b  that form a surface portion of the lower cover  507 , a first superimposed portion  509   c  placed on the rear side of the first surface portion  509   a , and a second superimposed portion  509   d  placed on the rear side of the first superimposed portion  509   c . An inner end t 1  in the rightward and leftward direction of the first front surface portion  509   a  and an inner end t 2  in the rightward and leftward direction of the second front surface portion  509   b  are butted against each other with a slit (gap) S between them. As shown in  FIG. 70 , the slit S extends in the vertical direction between the right and left legs. With the intermediate foldable portion  509  folded, the first superimposed portion  509   c  and the second superimposed portion  509   d  are covered by the first front surface portion  509   a  and the second front surface portion  509   b  and are therefore invisible from outside. (It shall be appreciated that only a part of the second superimposed portion  509   d  is visible through the slit S.) 
   For improved external appearance, the width of the slit S is made as small as possible, and is desirably substantially zero during design of the dimensions of the lower cover  507 . 
   When the intermediate air cells  511  protrusively expand, the intermediate foldable portion  509  expands in the rightward and leftward direction so as to increase an area of the cover surface.  FIGS. 73(   a ) and  73 ( b ) are views showing how the intermediate foldable portion  509  expands. As shown in  FIG. 73(   a ), with the intermediate foldable portion  509  folded, the first and second superimposed portions  509   c  and  509   d  are invisible from outside except for a region corresponding to the slit S having a small gap. 
   When the intermediate air cells  511  protrusively expand, the intermediate foldable portion  509  expands, causing the first and second superimposed portions  509   c  and  509   d  to be exposed on the front side of the cover. Thereby, the region of the lower cover  507  that covers the leg rest  504  extends in the rightward and leftward direction so as to increase the area of the cover surface. 
   Thus, since the cover extends according to expansion of the intermediate foldable portion  509 , the cover need not be made of elastic materials but may be made of non-elastic material such as artificial leather or genuine leather. If the cover is made of elastic material, expansion and contraction of the elastic material is less, because the cover extends according to the expansion of the foldable portion. Therefore, even when the cover is made of the elastic material, durability improves and external appearance is maintained. Further, elastic material is typically more expensive than non-elastic materials such as artificial leather, and thus a low cost is achieved by using the non-elastic material. In view of this, the cover is suitably made of artificial leather. 
   As shown in cross-sectional view of  FIG. 72(   a ), the four cover elements, i.e., the first front surface portion  509   a , the second front surface portion  509   b , the first superimposed portion  509   c , and the second superimposed portion  509   d , which form the intermediate foldable portion  509 , are separate from each other within the intermediate foldable portion  509 . The integral lower cover  507  is formed by coupling end portions of the separate cover elements suitably by stitching them up together. Specifically, a region near one end t 3  of the first superimposed portion  509   c  and a region near the inner end t 1  of the first front surface portion  509   a  are stitched up together to form a first coupled portion c 1 . A region near an opposite end t 4  of the first superimposed portion  509   c  and a region near one end t 5  of the second superimposed portion  509   d  are stitched up together to form a second coupled portion c 2 . Furthermore, a region near an opposite end t 6  of the second superimposed portion  509   d  and a region near an inner end t 2  in the rightward and leftward direction of the second front surface portion  509   b  are stitched up together to form a joint g. 
   In this embodiment and embodiments below, stitching is employed as a coupling method of the coupled portions and the joints, but is merely exemplary. It shall be appreciated that when the cover elements are stitchable, stitching is desirable as the coupling method because of its high coupling strength and low cost. 
   The first and second coupled portions c 1  and c 2  and the joint g have different configurations. Specifically, in the cross-sectional view of  FIG. 72(   a ), the two elements to be stitched up together extend from the coupled portions c 1  and c 2  in the same direction, while two elements to be stitched up together extend from the joint g in opposite directions. In such a configuration, the first superimposed portions  509   c  and the second superimposed portion  509   d  are folded toward the same side (left side in  FIG. 72(   a )), the first superimposed portion  509   c  is placed on the rear side of the first front surface portion  509   a , and the second superimposed portion  509   d  is placed on the rear side of the first superimposed portion  509   c.    
   In the folded state, the first front surface portion  509   a , the first superimposed portion  509   c , the second superimposed portion  509   d , and the second front surface portion  509   b  are all substantially parallel to a cover surface h. As used herein, the term “cover surface” refers to a region of the intermediate foldable portion  509  that forms an outer surface of the cover, and in the embodiment of  FIG. 72(   a ), an outer surface of the first front surface portion  509   a  and an outer surface of the second front surface portion  509   b  in the intermediate foldable portion  509  form the cover surface h. 
     FIG. 72(   b ) shows an alternative of the intermediate foldable portion  509 . Here, the second front surface portion  509   b  which is integral, including the second front surface portion  509   b  and the second superimposed portion  509   d , which are separate in the embodiment of  FIG. 72(   a ), is employed, thus omitting the joint g of the embodiment of  FIG. 72(   a ). In this case, the coupled portion or the joint which is visible from outside in the folded state is only the first joint c 1 , and thereby, external appearance advantageously improves because of the absence of the slit S. 
   In the embodiment of  FIG. 72(   a ), the first coupled portion c 1  and the second coupled portion c 2  are provided and the cover elements  509   a ,  509   c , and  509   d  which are folded substantially in parallel and superimposed are coupled in the thickness direction at the regions in the vicinity of the coupled portions c 1  and c 2 . Since the coupled state of the superimposed cover elements causes a restricting force, the foldable portion which expands by protrusion of the protrusible and retractable system easily returns to its folded state when the protrusible and retractable system retracts. The detail of effects caused by the restricting force will be described later. 
   In the structure in which the joint g is provided as shown in  FIG. 72(   a ), since the second front surface portion  509   b  and the second superimposed portion  509   d  which are superimposed in parallel in the region k near the joint g are coupled to each other in the thickness direction as described above, rigidity in the region superimposed in parallel increases. As a result, after expanding, the foldable portion easily returns to its folded state. Since the joint g is provided along with the first coupled portion c 1 , the first front surface portion  509   a  and the second front surface portion  509   b  are butted against each other with the slit S interposed between them, and tend to be flush with each other, decreasing a step in the cover surface in the folded state. As a result, external appearance improves and the step, which may be an obstruction to the user, is minimized. 
   By providing the joint g, external design appearance advantageously improves. In the perspective view of  FIG. 70 , stitch lines  525  are provided to extend on both sides of the slit S in the intermediate foldable portion  509 . These two stitch lines  525  extend from the back rest  503 , through the seat portion  502 , through both sides of the intermediate foldable portion  509 , and to a lowermost portion of the leg rest  504 , along with a center line L 2  in the rightward and leftward direction. 
   One of the stitch lines  525  on both sides of the intermediate foldable portion  509  is a stitch line at the joint g in  FIG. 72  between the second front surface portion  509   b  and the second superimposed portion  509   d  of  FIG. 72 . By stitching the cover elements up in the vicinity of the joint g, the two stitch lines  525  continuously extend from a region of the lower cover  507  which covers the seat portion to a lowermost portion of the leg rest that is covered. As result, external design appearance improves. As shown in  FIG. 72(   b ), without the joint g, the stitch line, along which the second front surface portion  509   b  and the second superimposed portion  509   d  in  FIG. 72(   a ) are stitched up together, is omitted. Therefore, only one stitch line  525 , along which the first front surface portion  509   a  and the first superimposed portion  509   c  are stitched up together, extends along the slit S in the intermediate foldable portion  509 , rather than the stitch lines  525  extending on both sides of the slit S in  FIG. 70 . Nonetheless, the stitch lines provided on right and left sides of the slit S by providing the joint g, improve external design appearance. In this manner, the respective cover elements of the foldable portion  509  are coupled by stitching and by providing the stitch line continuously with another stitch line. As a result, external design appearance improves. 
   Furthermore, since the second front surface portion  509   b  and the second superimposed portion  509   d  are separate rather than integral, the first front surface portion  509   a  and the second front surface portion  509   b  are equal in size, and hence the same cut pattern may be advantageously used. 
   As shown by a broken line of  FIG. 71 , a rear cover  531  is provided between the lower cover  507  and the support surface  518  of the leg rest  504 , and the rear cover  531  and the lower cover  507  are stitched up together. The rear cover  531  is made of elastic material, for example a material formed into a wet suit. The rear cover  531  allows the intermediate foldable portion  509  to return to its folded state more easily. Furthermore, since the protrusible and retractable system  508  does not directly contact the lower cover  507 , events in which a strong stress is applied to the lower cover  507  due to engagement of the lower cover  507  with the protrusible and retractable system  508  do not take place when the protrusible and retractable system  508  is protruding. As a result, durability of the lower cover  507  improves. 
   The stitching position in the region k near the coupled portion c 1  or c 2  is desirably set such that a distance d (see  FIG. 72(   a )) between the end position of the two elements to be stitched together and the stitching position is between 3 to 7 mm. If the distance d is too small, then a superimposed and stitched region α decreases, causing the foldable portion  509  to be less likely to return to is folded state. Conversely, if the distance d is too large, then the cover elements are wasted. 
   The material of the cover elements is not specifically limited, but the cover elements having bending rigidity with a predetermined degree or more is desirably used to enable the foldable portion to easily return to its folded state. Nonetheless, if the bending rigidity is too high, then the foldable portion is difficult to expand, and therefore, leather (artificial leather or genuine leather) with a thickness of 0.4 mm to 1 mm, more preferably 0.5 mm to 0.75 mm, is used. 
   Since the intermediate foldable portion  509  is folded to extend in parallel with the cover surface h of the intermediate foldable portion  509  and the support surface  518  of the intermediate foldable portion  509  is substantially flat in retraction, the intermediate foldable portion  509  protrudes outward least and becomes substantially flat. Therefore, the user easily places legs  517  on the lower cover  507  without being disturbed by the intermediate foldable portion  509 . Also, the lower cover  507  improves external appearance. 
   The protrusible and retractable system  508  covered by the lower cover  507  forms the support surface  518  (see  FIG. 79 ) which is substantially flat in retraction, and the intermediate foldable portion  509  covers a part of the support surface  518 . In this case, the intermediate foldable portion  509  is folded in parallel with the substantially flat support surface  518 , and flatness of the support surface  518  is not substantially reduced by the intermediate foldable portion  509 . Therefore, the intermediate foldable portion  509  of the lower cover  507  does not interfere with the legs  517  of the user placed on the support surface  518 . In addition, the intermediate foldable portion  509  does not interfere with the leg rest  504  which is used as a simple leg rest. As described above, since the flatness of the substantially flat support surface  518  is not substantially reduced, its external appearance of the cover improves. 
   As shown in  FIG. 70 , three lines L 1 , L 2 , and L 3  are provided on the cover  501  covering the chair body  505  to extend in the vertical direction from the back rest cover  506  to the lower cover  507  in order to improve external design appearance. The intermediate foldable portion  509  extends along a lower region of the center line L 2  in the rightward and leftward direction, and the first coupled portion c 1  and the joint g (see  FIG. 72(   a )) of the intermediate foldable portion  509  form the lower portion of the center line L 2 . The stitch lines  525  are positioned on right and left sides of the center line L 2  to extend to the lowermost region of the lower cover  507 . 
   As shown in  FIG. 73 , in regions  533  near the intermediate foldable portion  509  which are positioned on both sides of an extended line of a line including the coupled portion c 1  of the intermediate foldable portion  509 , the respective cover elements (first front surface portion  509   a , the second front surface portion  509   b , the first superimposed portion  509   c , and the second superimposed portion  509   d ) are stitched up together so as not to expand. Thereby, expansion of the intermediate foldable portion  509  is restricted at both end positions in the direction of the line formed by the coupled portion. Therefore, the intermediate foldable portion  509  is restricted to be in the folded state, and easily returns to its folded state during retraction of the intermediate air cell  511 . While in this embodiment, regions near the both ends in the direction of the line formed by the coupled portion of the foldable portion  509  are unexpandable, only one side in the direction of the line formed by the coupled portion may alternatively be expandable. 
   The positions of the unexpandable regions  533  of the intermediate foldable portion  509  are set in association with placement of the intermediate air cells  511 . As shown in  FIG. 73(   a ), a length Lc in the direction of the line formed by the coupled portion c 1  forming the slit S is set larger than a length Le in the direction of the line formed by the coupled portion of the intermediate air cell  511  which is the protrusible and retractable system mounted in the vicinity of the intermediate foldable portion  509 . Thereby, the intermediate air cell  511  is protrusible substantially without restriction by the unexpandable regions  533 . 
   In this case, the intermediate air cell  511  which is the protrusible and retractable system is desirably placed at the center position in the direction of the line formed by the coupled portion of the intermediate foldable portion  509 . In this case, since the distance between the intermediate air cell  511  and the unexpandable region ( 533 ) is equal on both sides of the intermediate air cells  511  and therefore a restricting force is applied evenly. 
   The leg rest  504  is vertically slidable according to the positions of the legs  517  of the user, and a vertical relative position of the lower cover  507  and the intermediate air cell  511  may be variable. In this case, it is desirable to set the length Lc larger than the length Le so that vertical both ends of the intermediate air cell  511  are inward (closer to the center in the vertical direction) relative to vertical both ends of the intermediate foldable portion  509  in a sliding range of the intermediate air cell  511 . 
   As shown in  FIG. 70 , in this embodiment, the three lines L 1 , L 2 , and L 3  extend. As shown in  FIG. 71 , a foldable portion is not formed in a region of the lower cover  507  that covers the leg rest  504 , which corresponds to the lines L 1  and L 3 . That is, the lines L 1  and L 3  located on right and left sides of the intermediate foldable portion  509  are typically provided to meet design requirements. 
   As shown in  FIG. 71 , the intermediate foldable portion  509  is positioned to avoid the right and left legs  517  of the body of the user, i.e., between the right and left legs  517 . In such a configuration, since the intermediate foldable portion  509  is not located between the legs  517  and the protrusible and retractable system  508  (massaging apparatus), it is smoothly expandable during protrusion and expansion of the intermediate air cells  511 . In addition, discomfort caused by the intermediate foldable portion  509  expanding between the legs  517  and the protrusible and retractable system  508  is avoided. 
   As should be appreciated from the above, the foldable portion is desirably placed at the position where the body of the user is not placed. As used herein, the “position where the body of the user is not placed” refers to those positions other than positions where the body is placed when the leg rest is used as the massaging apparatus. 
   The intermediate foldable portion  509  is placed in the vicinity of the intermediate air cells  511  so as to cover the intermediate air cells  511 . If the intermediate foldable portion  509  is distant from the intermediate air cells  511 , the cover moves in the direction from the intermediate foldable portion  509  toward the intermediate air cells  511  according to the expansion of the intermediate air cells  511 . In this case, if the leg  517  is placed on the moving cover, an external force which is irrelevant to a force to be applied to the leg  517 , may be applied to the leg  517 , causing discomfort. In addition, since the cover moves to a large extent by the expansion of the intermediate foldable portion  509 , the expansion does not take place smoothly. In this embodiment, since the intermediate foldable portion  509  is positioned in the vicinity of the intermediate air cells  511 , it is possible to minimize the movement of the cover when the intermediate foldable portion  509  expands. Therefore, the intermediate foldable portion  509  is expandable smoothly, and the user does not suffer discomfort which may otherwise be caused by the movement of the cover between the body and the massaging apparatus. 
   Thus, the foldable portion is positioned preferably in the vicinity of the protruding range of the protrusible and retractable system, more preferably within the protruding range of the protrusible and retractable system. In this case, the region of the cover that may move according to expansion of the cover is minimized. As a result, the foldable portion is smoothly expandable, and the user does not suffer discomfort which may otherwise be caused by the movement of the cover between the body and the massaging apparatus. 
   In the folded state, the first superimposed portion  509   c  and the second superimposed portion  509   d  of the intermediate foldable portion  509  are accommodated on the rear surface side of the cover surface h, i.e., on the rear surface side (inside) of the first front surface portion  509   a  and the second front surface portion  509   b . In other words, the intermediate foldable portion  509  is folded to be accommodated on the rear surface side of the cover surface h. Since the first superimposed portion  509   c  and the second superimposed portion  509   d  are accommodated in the folded state on the rear surface side of the cover, they are therefore less conspicuous, resulting in improved external appearance. Furthermore, the user is not disturbed by the first superimposed portion  509   c  and the second superimposed portion  509   d  which are loosely folded and exposed on the front side (outer side). 
   As shown in  FIG. 71 , bellows-like foldable portions  526  are provided at both end portions in the rightward and leftward direction of the lower cover  507  of the sixteenth embodiment. The bellows-like foldable portions  526  expand when the lower air cell  514  and the upper air cell  515  of the protrusible and retractable system  508  expand to cause the protrusible plate  513  and the receiver plate  522  to protrude. As described above, since the lower cover  507  is not fixed to the leg rest  504 , the lower cover  507  is unable to move according to protrusion of the receiver plates  522  (or expansion of the upper air cells  515 ) without the bellows-like foldable portion  526 , causing the lower cover  507  to disengage from the leg rest  504 , or to displace from a position where the lower cover  507  covers the leg rest  504 . Nonetheless, disengagement or displacement of the lower cover  507  is inhibited because of the presence of the bellows-like foldable portion  526 . 
   Unlike general bellows-like covers, the bellows-like foldable portion  526  easily returns to its folded state.  FIG. 74  is an enlarged cross-sectional view of the bellows-like foldable portion  626 . As shown in  FIG. 74 , in its folded state, a front surface portion  526   a , a first superimposed portion  526   b , a second superimposed portion  526   c , a third superimposed portion  526   d , a fourth superimposed portion  526   e , a fifth superimposed portion  526   f , a sixth superimposed portion  526   g , and a rear portion  526   h , which are cover elements forming the bellows-like foldable portion  526 , are folded substantially in parallel with the support surface  518  of the protrusible and retractable system  508  in retraction. The cover elements  526   a  to  526   h  in a folded state are coupled (stitched together) in the thickness direction in regions k near the coupled portions c. Therefore, as in the above mentioned intermediate foldable portion  509 , the bellows-like foldable portion  526  easily returns to its folded state in retraction of the protrusible and retractable system  508 . As a result, external appearance is improved. 
   Embodiment 17 
     FIG. 75  is a cross-sectional view showing a state in which a lower cover  507  according to a seventeenth embodiment of the present invention covers a protrusible and retractable system  508 . In the seventeenth embodiment, in addition to the intermediate foldable portion  509 , right and left foldable portions  519  are provided as foldable portions which are folded substantially in parallel with the support surface  518  on the support surface  518  of the protrusible and retractable system  508 . In addition, the bellows-like foldable portions  526  of the sixteenth embodiment are omitted. 
     FIG. 76  is an enlarged cross-sectional view of the intermediate foldable portion  509  of the seventeenth embodiment. The intermediate foldable portion  509  of the seventeenth embodiment is structured such that the first front surface portion  509   a  and the second front surface portion  509   b  are butted against each other with the slit S interposed between them. An end portion on the slit S side of the first front surface portion  509   a  and an end portion on the slit S side of the first superimposed portion  509   c  are stitched up together to form a first coupled portion c 1 . An end portion on the slit S side of the second front surface portion  509   b  and an end portion on the slit S side of the third superimposed portion  509   e  are stitched up together to form a fourth coupled portion c 4 . Further, end portions on the opposite side of the slit S side of the superimposed portions  509   c  and  509   e  and the both end portions of the second superimposed portion  509   d  are stitched up together to form a second coupled portion c 2  and a third coupled portion c 3 , respectively The first superimposed portion  509   c  and the third superimposed portion  509   e  have an equal width in the rightward and leftward direction, and the second superimposed portion  509   d  has a width in the rightward and leftward direction which is approximately twice as large as that of these superimposed portions  509   c  and  509   e . In the folded state, all the cover elements  509   a  to  509   e  are substantially parallel to the cover surface h. 
   The right and left foldable portions  519  have a folded structure shown in the embodiment of  FIG. 72(   b ). The perspective view of the lower cover  507  of  FIG. 75  is shown in  FIG. 70 . The lower cover  507  of  FIG. 75  is provided with three lines L 1  to L 3  extending in the vertical direction, among which the lines L 1  and L 3  positioned on right and left sides of the intermediate foldable portion  509  are slits including the first coupled portions c 1  (see  FIG. 72(   b )) of the right and left foldable portions  519 . 
   In this manner, by providing the lines including the coupled portions of the foldable portion in the folded state on extended lines of another lines on the cover  501 , the lines including the coupled portions are integral with the other lines and are less conspicuous. In addition, external design appearance improves. When a plurality of foldable portions are provided, other lines which are visible on the cover  501  may be provided on extended lines of the lines including the coupled portions resulting from a plurality of foldable portions. The number and direction of the lines including the coupled portions and lines partially including these lines of the coupled portions are not specifically limited. 
   In this embodiment, as in the intermediate foldable portion  509  of the sixteenth embodiment, the intermediate foldable portion  509  is configured to easily return to its folded state during retraction of the protrusible and retractable system  508 . All the cover elements  509   a  to  509   e  are separate at the stitching positions, and all the coupled portions c 1  to c 4  are formed by stitching, in the thickness direction, the cover elements  509   a  to  509   e  superimposed in the folded state in parallel with each other in the regions k near the coupled portions c 1  to c 4 . Therefore, the foldable portion  509  of the seventeenth embodiment easily returns to its folded state as in the intermediate foldable portion  509  of the sixteenth embodiment. 
   Since in the folded state, the first superimposed portion  509   c , the second superimposed portion  509   d , and the third superimposed portion  509   e  which are folded and become deformed are accommodated on the rear side of the cover surface h, i.e., on the rear side of the first and second front surface portions  509   a  and  509   b , their external appearance improves and the deformed regions do not interfere with the user. 
   Subsequently, how the cover  507  of the seventeenth embodiment expands when the protrusible and retractable system  508  protrudes and retracts will be described. In a contracted (retracted) state of the intermediate air cells  511 , the intermediate foldable portion  509  is folded as shown in  FIG. 81(   a ). On the other hand, in an expanded (protruded) state of the intermediate air cell  511 , the intermediate foldable portion  509  expands as shown in  FIG. 81(   b ). Therefore, the lower cover  507  is expandable according to the expansion (protrusion) of the intermediate air cells  511 . 
   As described above, the intermediate foldable portion  509  is structured such that the cover elements  509   a  to  509   e  superimposed in the folded state substantially in parallel are stitched up together in the thickness direction in the regions near the first to fourth coupled portions c 1  to c 4 . The restricting force resulting from this stitching causes the first superimposed portion  509   c  to be curved in substantially U-shape at right and left end regions (near the first coupled portion c 1  and the second coupled portion c 2 ), in the expanded state of  FIG. 81(   b ). The restricting force causes the third superimposed portion  509   e  to be also curved in substantially U-shape at right and left end regions (near the third coupled portion c 3  and the fourth coupled portion c 4 ). The cover elements such as the first superimposed portion  509   c  and the third superimposed portion  509   e  have bending rigidity of a predetermined value, and a force for causing these cover elements to return to its substantially flat state is exerted when they are bent. When a bending degree (curvature) is larger as in the above mentioned curved state, the force for causing the cover elements to return its substantially flat state becomes larger. Since the restricting force resulting from the stitching increases the curvature of the cover element during expansion, the cover elements are more likely to return to its folded state. When the intermediate air cell  511  re-contracts from the expanded state of  FIG. 81(   b ), the intermediate foldable portion  509  easily return to its folded state. 
   The right and left foldable portions  519  expand according to the expansion (protrusion) of the upper air cells  515  of the right and left air cells  512 .  FIG. 82  shows how each of the right and left foldable portions  519  expands. In  FIG. 82 , the lower air cell  514 , the receiver plate  522 , the pressing element  523 , and other elements are suitably omitted. 
   With the protrusible plate  513  protruding by expansion of the lower air cell  514  (not shown) as shown in  FIG. 82(   a ), each of the right and left foldable portions  519  does not substantially expand. This is because each of the end portions  530  of the lower cover  507  is sandwiched between the protrusible plate  513  and the lower air cell  514 , and not fixed to the leg rest  504  side, so that the lower cover  507  is not pulled by protrusion of the protrusible plate  513 . When the upper air cell  515  expands (protrudes) as shown in  FIG. 82(   b ), each of the right and left foldable portions  519  expands. If the right and left foldable portions  519  are not provided, the end portions  530  of the lower cover  507  tend to move according to the expansion of the upper air cell  515 , causing the lower cover  507  to disengage and displace from the leg rest  504 . This does not occur because the right and left foldable portions  519  expand. 
   In the expanded state of  FIG. 82(   b ), the cover elements are curved in the vicinity of the first coupled portion c 1  and the second coupled portion c 2  of each of the right and left foldable portions  519 . Therefore, the force for causing the foldable portion  519  to return to the substantially folded state is exerted, causing the foldable portion  519  to easily to return its folded state. 
     FIG. 83  shows how an alternative of the foldable portion  519  expands. The alternative of the foldable portion  519  is configured as in the intermediate foldable portion  509  in the embodiment of  FIG. 76 . Since the foldable portion  519  expands as shown in  FIG. 83(   b ) during expansion of the upper air cell  515 , and the cover elements are curved at the coupled portions c 1  to c 4 , it easily returns to its folded state by the force causing the foldable portion  519  to return its initial state. 
   Since intermediate foldable portion  509  of the seventeenth embodiment of  FIG. 76  is symmetric in the rightward and leftward direction, it easily expands evenly rightward and leftward. Therefore, as shown in  FIG. 75 , by causing a protrusion symmetric axis of the two intermediate air cells  511  which is the protruding system that is protrusible evenly rightward and leftward to conform to a symmetric axis of the foldable portion  509 , the foldable portion  509  becomes expandable more smoothly. 
     FIGS. 77(   a ) and  77 ( b ) show alternatives of the intermediate foldable portion  509 . As a matter of course, these foldable structures may be employed in all foldable positions such as the right and left foldable portions  519 . 
   As compared to the embodiment of  FIG. 72(   a ), the joint g is located on the rear side (lower side) of the first front surface portion  509   a  and the first superimposed portion  509   c  in the embodiment of  FIG. 77(   a ). The joint g is accommodated on the rear side of the cover surface h. In such a structure, since the joint g hides behind in the folded state, only one coupled portion c 1  is visible and the slit S (see  FIG. 72(   a )) does not occur. It shall be appreciated that, unlike the embodiment of  FIG. 72(   a ), the first front surface portion  509   a  and the second front surface portion  509   b  are not butted against each other and a step is formed at the first coupled portion c 1 . 
   The embodiment of  FIG. 77(   b ) is similar to that of  FIG. 76 , and has coupled portions c 1  to c 4 . The embodiment of  FIG. 77(   b ) is different from that of  FIG. 76  in that the fourth coupled portion c 4  is located on the rear side (lower side) of the first front surface portion  509   a  and the first superimposed portion  509   c , and is accommodated on the rear surface side of the cover surface  76 . In this structure, the first coupled portion c 1  and the fourth coupled portion c 4  are not butted against each other unlike the embodiment of  FIG. 76 , and there is a step at the first coupled portion c 1 . On the other hand, since the fourth coupled portion c 4  hides behind in the folded state, only one coupled portion c 1  is visible from outside, and therefore, the slit S (see  FIG. 76)  does not occur advantageously. 
   When the maximum number of the superimposed cover elements in the folded state is four or less, or three or less, the protruding amount of the foldable portion in the folded state desirably becomes minimized. In the intermediate foldable portion  509  of  FIG. 72(   a ), the maximum number is three (i.e., first front surface portion  509   a , the first superimposed portion  509   c , and the second superimposed portion  509   d ). Likewise, the intermediate foldable portion  509  includes three cover elements in the embodiment of  FIG. 76 . The foldable portion of  FIG. 77(   a ) includes four cover elements (i.e., the first front surface portion  509   a , the first superimposed portion  509   c , the second superimposed portion  509   d , and the second front surface portion  509   b ), while the foldable portion of  FIG. 77(   b ) includes five cover elements. If the maximum number of the superimposed cover elements increases, then the cover is swollen greatly, so that the body is difficult to place thereon and its external appearance degrades. Since it is typically necessary to superimpose three or more cover elements to form the foldable portion, the maximum number of the superimposed elements is preferably three or four, more preferably three in order to improve flatness of the cover. 
   The above described massaging apparatus in the respective embodiments is provided with the leg rest  504  including the support surface  518  on which the right and left legs are supported, and the protrusible and retractable system  508  configured to protrude and retract with respect to the legs  517 , and the cover  501  configured to cover the support surface  518  and including the intermediate foldable portion  509  configured to expand according to protrusion and to be folded according to retraction. In this massaging apparatus, the support surface  518  that supports the body and has the protrusible and retractable system is covered with the cover. Because of the presence of the foldable portion that is capable of expanding and being folded according to the protrusion and retraction, the cover need not be made of an elastic material, and its amount of expansion and contraction decreases if the cover is made of the elastic material. The elastic material decreases elasticity and becomes deformed after repeated expansion and contraction during use. In accordance with the above configuration, since the cover need not be made of the elastic material, and its expansion and contraction amount decreases if it is made of the elastic material, its external appearance is maintained. 
   In the above mentioned embodiments, the region of the lower cover  507  that covers the leg rest  504  functions as the cover for the leg rest. The cover for the leg rest is configured to cover the leg rest  504  including the support surface  518  on which the right and left legs are supported, and the protrusible and retractable system is configured to protrude and retract with respect to the legs  517  within the support surface  518 . The cover includes the intermediate foldable portion  509  which is an expandable and contractable portion that is placed on the intermediate region in the rightward and leftward direction of the support surface  518  and is capable of expanding and retracting according to protrusion and retraction. 
   In order to enable the leg rest  504  to massage the right and left legs, a separating wall is typically provided between these legs to allow these legs to be supported from inward, because the legs are required to be respectively massaged. The separating wall makes it difficult to place the legs on the leg rest  504 . It is therefore desirable to provide the protrusible and retractable system configured to protrude between the right and left legs, because the separating wall is omitted and thus the legs are easily placed thereon. In this case, by placing the expandable and contractable portion on the intermediate region in the rightward and leftward direction of the support surface  518 , the cover expands according to protrusion and contracts according to retraction in the intermediate region. Since the cover contracts according to retraction, it does not substantially interfere with the legs during retraction. In addition, since the expandable and contractable portion is positioned in the intermediate region in the rightward and leftward direction between the right and left legs  517  so as to avoid the positions of the legs  517 , it is expandable and contractable smoothly, and discomfort felt by the user is minimized. 
   Furthermore, since the support surface  518  of the leg rest  504  is substantially flat in retraction of the protrusible and retractable system  508 , the legs are placed on the leg rest  504  more easily and its external appearance improves. 
   The expandable and contractable portion may be made of, for example, various types of elastic materials. It shall be understood that the elastic material decreases elasticity and becomes deformed after its repeated expansion and contraction. In order to maintain the external appearance, the foldable portion is desirably made of non-elastic material such as leather (e.g., artificial leather) and is desirably the intermediate foldable portion  509 . Since the foldable portion is configured to be foldable substantially in parallel with the cover surface h, a protruding amount of the cover on the support surface  518  of the leg rest  504  becomes minimized, and the cover allows the legs to be easily placed thereon while maintaining its external appearance. As mentioned previously, these effects are enhanced when the support surfaces  518  are substantially flat. 
   The above mentioned foldable structures of the intermediate foldable portion  509  or the right and left foldable portions  519  are not intended to be employed in only the regions that cover the leg rest  504 , but may be applied to foldable portions at all positions of the massaging apparatus, for example, the back rest  503 , the arm rest  510 , the seat portion  502 , and other elements. The present invention is applicable to massaging apparatus associated with protruding and retracting operations other than the chair-type massaging apparatus mentioned above. Moreover, the protruding and retracting operations are not intended to be massage operations. 
   Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, the description is to be construed as illustrative only, and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and/or function may be varied substantially without departing from the spirit of the invention and all modifications which come within the scope of the appended claims are reserved. 
   INDUSTRIAL APPLICABILITY 
   A chair-type massaging apparatus, a cover for a massaging apparatus, a cover for a leg rest, and a massaging apparatus of the present invention are useful as a chair-type massaging apparatus comprising a leg rest on which lower legs of a user are supported, a cover for a massaging apparatus or a leg rest that is configured to massage a body such as legs, and a massaging apparatus comprising these covers.