Patent Publication Number: US-2009227912-A1

Title: Chair-type Massaging Machine

Description:
TECHNICAL FIELD 
     The present invention relates to a chair-type massaging machine. 
     BACKGROUND ART 
     Some of the chair-type massaging machines are adapted to massage heels and soles. Japanese Laid Open Patent Application Publication No. 2004-215938 (hereinafter, referred to as “Prior-Art Document”), for example, discloses a chair-type massaging machine which includes: a sole support surface for supporting massagee&#39;s soles rested thereon, and a heel support surface upstanding from a rear side of the sole support surface for supporting heels on the rear sides thereof, wherein the heel support surface is provided with a heel massaging portion for clamping and pressing a rear part of each heel, and wherein the sole support surface is provided with a sole massaging portion for pressing each sole. 
     DISCLOSURE OF THE INVENTION 
     A heel of human body is configured to be progressively decreased in width toward the rear end thereof. Therefore, a pressing force of the heel massaging portion clamping and pressing the heel is directed toward a toe side as inclined relative to a longitudinal direction of the sole, so that a component force toward the toe is produced. 
     This may lead to the following problem. The heel is pushed out by the heel massaging portion clamping the heel, so as to be displaced from the heel massaging portion. Hence, the heel massaging portion may be unable to apply an effective pressure to the heel. Furthermore, when the heel is pushed out as described above so that the sole is moved toward the toe, a pressure point on the sole is displaced so that a massage effect on the sole is also decreased. 
     In view of the foregoing, the invention has an object to provide a chair-type massaging machine capable of applying effective massage to the heel and sole. 
     The invention has contrived the following technical features to achieve the above object. 
     Specifically, the chair-type massaging machine according to the invention comprises: a seat surface for a massagee to be seated thereon; a plantar-arch projection for the seated massagee to place plantar arches thereon; and a heel massaging portion capable of clamping and pressing heels in a feet-resting position where the plantar arches rest on the plantar-arch projection. 
     In this case, the machine is adapted to massage the heel as allowing the plantar arch of the foot to be pressed against a projected portion of the plantar-arch projection. By virtue of a physical locking effect of the plantar-arch projection, the sole is less prone to be displaced (moved) toward the toe when the heel is clamped and pressed. In addition, the plantar-arch projection has an acupressure effect on the plantar arch. As a result, the heel and plantar arch may be effectively massaged. 
     It is preferred that a space extending sole-normally downwardly of the plantar-arch projection is provided at an area around the plantar-arch projection and on a heel-location side with respect to the feet-resting position. In this case, the degree of freedom of setting contact angle or abutting positions of the soles relative to the plantar-arch projection is increased because the massagee is allowed to insert the massagee&#39;s heels into the above space by varying the angles of ankles. Accordingly, the plantar-arch projection may provide an even higher massage effect on the soles. 
     It is further preferred that the space defined around the plantar-arch projection and on the heel-location side with respect to the feet-resting position is open downward in the sole-normal direction. In this case, the aforesaid space on the heel-location side is provided. What is more, the above space prevents the soles from getting sweaty or prevents dirt and dust separated from the soles from being accumulated in the neighborhood of the plantar-arch projection. Thus are ensured quite comfortable conditions for sole massage. 
     It is further preferred that a space capable of receiving the heels is provided at place sole-longitudinally rearwardly of the heel location with respect to the feet-resting position. In this case, the massagee is allowed to shift sole-longitudinal positions of the soles by inserting the heels into the above space. This results in an increased degree of freedom of setting the sole-longitudinal positions of the soles. Hence, the massagee can press any desired parts of the soles against the plantar-arch projection. In addition, the degree of freedom of selecting the position of massage applied by the heel massaging portion is also increased. 
     It is further preferred that the plantar-arch projection is exposed for directly contacting the plantar arches of the massagee&#39;s feet. 
     In this case, the plantar-arch projection is prevented from being flattened due to a cover member and the like covering the plantar-arch projection. Therefore, the physical locking effect of the plantar-arch projection is enhanced even further, so that a more effective massage may be applied to the plantar arches and the heels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a chair-type massaging machine according to one embodiment of the invention; 
         FIG. 2  is a side view of the chair-type massaging machine of  FIG. 1 ; 
         FIG. 3  is a diagram of a second segment of a footrest as viewed from above along a sole-normal direction; 
         FIG. 4  is a diagram of the second segment of the footrest as viewed from front along a sole-longitudinal direction; 
         FIG. 5  is a diagram illustrating how the feet of a massagee are massaged by the second segment; 
         FIG. 6  is a side view of the chair-type massaging machine for disclosing a reclining mechanism and a footrest angle interlocking mechanism, the view showing a state where a backrest is raised to the uppermost position; 
         FIG. 7  is a side view of the chair-type massaging machine for disclosing the reclining mechanism and the footrest angle interlocking mechanism, the view showing a state where the backrest is inclined to a lower position than that of  FIG. 6 ; and 
         FIG. 8  is a group of diagrams showing abutment relation between a plantar-arch projection  5   t  and a foot. 
     
    
    
     DESCRIPTION OF REFERENCE CHARACTERS 
     
         
           1 : Chair-type massaging machine 
           3 : Seat 
           3   a : Seat surface 
           5 : Footrest 
           53 : Heel massaging air cell (heel massaging portion) 
           5   t : plantar-arch projection 
         U: Sole-longitudinal direction 
         H: Sole-normal direction 
         k 1 : First space (space defined sole-longitudinally rearwardly of heel location with respect to feet-resting position) 
         (k 2 : Second space (space defined at an area around the plantar-arch projection and on a heel-location side with respect to the feet-resting position and extending sole-normally downwardly of the plantar-arch projection) 
         h: Massagee 
         h 1 : Sole 
         h 3 : Heel 
         h 6 : Plantar arch 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     A preferred embodiment of the invention will hereinbelow be described with reference to the accompanying drawings. 
       FIG. 1  is a perspective view showing the whole body of a chair-type massaging machine  1  according to one embodiment of the invention, whereas  FIG. 2  is a side view thereof. As shown in these figures, the chair-type massaging machine  1  includes: a backrest  2  capable of supporting a seated massagee h on the back and the head; a seat  3 , an upper surface of which defines a seat surface  3   a  capable of supporting the hips and thighs of the massagee h; an armrest  4  disposed on lateral sides of the machine for supporting the arms of the massagee h; a footrest  5  for the massagee h to place the calves and soles therein.  FIG. 1  shows the footrest  5  removed of a cover in order to disclose an internal mechanism of the footrest  5 . 
     Although not shown in the figures, massaging members, such as an air cell, massaging element and vibrator, for applying massage to the massagee h are disposed at suitable places in the backrest  2  and the seat  3 . A lower part of the seat  3  accommodates an unillustrated air supply mechanism for supplying air to these air cells and air cells of the footrest  5  to be described hereinlater, an unillustrated controller for controlling the operations of the individual massaging members, and the like. As shown in  FIG. 1 , a plurality of air cells for massaging the calves, heels, soles and the like (the details of which will be described hereinlater) are disposed at the footrest  5 . 
     The chair-type massaging machine  1  includes a reclining mechanism r adapted to vary the angle of inclination of the backrest  2 .  FIG. 6  and  FIG. 7  are side views showing an internal mechanism of the reclining mechanism r. As shown in these figures, the reclining mechanism r includes: a frame member  7  disposed in the seat  3  and extended in a depth-wise direction of the seat  3 ; a first pivot shaft z 1  for pivotally interconnecting one end of the frame member  7  (end adjacent to the backrest  2 ) and a lower part of the backrest  2 ; a second pivot (shaft z 2  disposed at a bottom portion of the backrest  2 ; and a third pivot shaft z 3  disposed at the other end of the frame member  7  (end adjacent to the footrest  5 ). The second pivot shaft z 2  is disposed closer to a lower end of the backrest than the first pivot shaft z 1  with respect to a longitudinal direction of the backrest. The second pivot shaft z 2  is disposed at the lower end of the backrest  2 . The first pivot shaft z 1  is disposed at the lower part of the backrest  2  and at place near the seat surface of the seat  3 . An expandable/contractable actuator  6  has one thereof pivotally connected to a bottom portion of the backrest  2  by means of the second pivot shaft z 2 , and has the other end thereof pivotally connected to the other end of the frame member  7  by means of the third pivot shaft z 3 . According to the reclining mechanism r of such a structure, as the actuator is expanded longer, the backrest  2  is inclined lower. As the actuator  6  is contracted shorter, the backrest  2  is raised higher.  FIG. 6  shows a state where the backrest  2  is raised to the uppermost position.  FIG. 7  shows a state where the backrest  2  is inclined at a predetermined angle. 
     While the frame member  7  of the seat  3  is disposed on lateral sides of the seat  3 ,  FIG. 6  and  FIG. 7  omits the depiction of a front-side one of the lateral frame members  7  in the interest of easy view of the internal mechanism of the reclining mechanism r. 
     The chair-type massaging machine  1  further includes a footrest angle interlocking mechanism f which is operatively associated with the above inclination of the backrest  2  for varying the angle of the footrest  5  relative to the seat  3  (or an installation surface of the chair). As shown in  FIG. 6  and  FIG. 7 , the footrest angle interlocking mechanism f includes: a pivot shaft z 4  disposed at the bottom portion of the backrest  2 ; a link member  9  which has one end thereof connected to the bottom portion of the backrest  2  by means of the pivot shaft z 4  and has the other end thereof abutted against the footrest  5  (a backside portion  5   c  thereof); and a pair of rollers  15  for clamping the link member  9  as slidably moved between the one end and the other end thereof. The rollers  15  are fixed to a transverse frame member  8  which interconnects the respective other ends of the lateral frame members  7  as extended in the transverse direction thereof. The rollers  15  permit the sliding movement of the link member  9  as maintaining a distance between the seat  3  and the link member  9 . When the backrest  2  is inclined to lower position, the link member  9  is pivotally moved about the pivot shaft z 4  and is slidably moved toward the front side (footrest- 5  side) relative to the rollers  15 , thereby pushing up the footrest  5 . While the other end of the link member  9  is abutted against the backside portion of the footrest  5 , an abutting position thereof is not fixed. In conjunction with an inclining motion of the footrest  5 , therefore, the other end of the link member  9  pushes up the footrest  5  as sliding on the backside portion of the footrest  5  (sliding movement). 
     A more detailed description is made on the footrest  5 . The footrest  5  is pivotally mounted to a front portion of the seat  3  and is inclined relative to the seat  3  or the chair installation surface (horizontal plane) by means of the footrest angle interlocking mechanism f. 
     The footrest  5  further includes a first expanding/contracting mechanism for moving the footrest  5  toward or away from the seat  3 . As shown in  FIG. 7 , a first segment  5   a  of the footrest  5  is pivotally connected to the seat  3  by means of a footrest support shaft z 5 . The first segment  5   a  and the footrest support shaft z 5  are interconnected by means of a first slide member  5   d  slidably movable relative to the first segment  5   a . The first segment  5   a  is slidably moved on the first slide member  5   d , thereby varying a distance between the seat  3  and the footrest  5 .  FIG. 7  shows a state where the footrest  5  is moved away from the seat  3  by means of the first expanding/contracting mechanism. 
     The footrest  5  has an articulated structure which includes: the first segment  5   a  principally serving to massage the calves of the massagee h; and a second segment  5   b  principally serving to massage the heels, dorsa and soles of the feet of the massagee h. The footrest  5  further includes a second expanding/contracting mechanism for moving the second segment  5   b  toward or away from the first segment  5   a . As shown in  FIG. 7 , the first segment  5   a  and the second segment  5   b  are interconnected by means of a second slide member  5   e . The second slide member  5   e  is fixed to either one of the first segment  5   a  or the second segment  5   b  and is adapted for sliding movement relative to the other. A distance between the first segment  5   a  and the second segment  5   b  is varied by means of such a second slide member  5   e .  FIG. 7  shows a state where the first segment  5   a  and the second segment  5   b  are spaced away from each other by means of the second expanding/contracting mechanism. 
     The aforementioned first expanding/contracting mechanism and second expanding/contracting mechanism provide for the adjustment of positions of the first segment  5   a  and the second segment  5   b  according to the length of the leg of the massagee hand the seated position of the massagee. 
     Each of the first expanding/contracting mechanism and the second expanding/contracting mechanism includes an unillustrated elastic member (such as a spring) which urges the mechanism in a direction to reduce the expandable length thereof. Specifically, the first slide member  5   d  and the second slide member  5   e  are each provided with the elastic member such as a spring. The elastic member of the first slide member  5   d  urges the first slide member  5   d  in a direction to reduce the distance between the first segment  5   a  and the seat  3  (direction to contract the first slide member  5   d ). The elastic member of the second slide member  5   e  urges the second slide member  5   b  to reduce the distance between the first segment  5   a  and the second segment  5   b  (direction to contract the second slide member  5   e ). The slide members  5   d ,  5   e  may be expanded by applying thereto forces exceeding the urging forces of these elastic members in expanding directions. In a case where an elastic modulus (such as spring constant) of the elastic member of the first slide member  5   d  is greater than an elastic modulus (such as spring constant) of the elastic member of the second slide member  5   e , the second slide member  5   e  may be slidably moved by a greater quantity than that of the sliding movement of the first slide member  5   d . This is because the second slide member  5   e  having the smaller elastic modulus is expanded in preference to the first slide member  5   d  having the greater elastic modulus. Conversely, in a case where the elastic modulus (such as spring constant) of the elastic member of the first slide member  5   d  is smaller than the elastic modulus (such as spring constant) of the elastic member of the second slide member  5   e , the first slide member  5   d  may be slidably moved by a greater quantity than that of the sliding movement of the second slide member  5   e . This is because the first slide member  5   d  having the smaller elastic modulus is expanded in preference to the second slide member  5   e  having the greater elastic modulus. That is, if the elastic members (such as springs) are provided at both of the first expanding/contracting mechanism and the second expanding/contracting mechanism, the locations of the first segment  5   a  and the second segment  5   b  (the location of the footrest  5  relative to the seat  3 , and the distance between the first segment  5   a  and the second segment  5   b ) may be varied by adjusting the strength (elastic modulus) of each of the elastic members (spring). 
     As shown in  FIG. 1 , the first segment  5   a  of the footrest  5  includes first lateral-side walls  5   a   1  which upstand from the lateral sides thereof and oppose each other. These first lateral-side walls  5   a   1  are each provided with an outer air cell  51  at a lateral inside surface thereof, the outer air cells serving to press the calves on the outer sides thereof. On the other hand, center air cells  52  are provided at transversely intermediate places between the two first lateral-side walls  5   a   1 , the center air cells serving to press the calves on the inner sides thereof. These center air cells  52  are disposed on either side with respect to a transversely central line of the footrest  5 . When the massagee h receives a massage, the massagee places the individual legs (the calves) in individual spaces defined between the outer air cell  51  and the center air cell  52 . When supplied with air, the outer air cell  51  is inflated transversely inwardly, and the center air cell  52  is inflated transversely inwardly. Thus, the first segment  5   a  is able to massage the calves of the massagee h as clamping the calves by means of the outer air cells  51  and the center air cells  52 . 
     Next, description is made on the second segment  5   b  of the footrest  5 . 
     According to the invention, individual directions with respect to the footrest  5  and the second segment  5   b  are defined as follows. In a standard feet-resting position wherein the massagee h is seated with the legs placed in the footrest  5  in normal position to form an angle of substantially 90° at the ankle, as shown in  FIG. 2 , a direction substantially along a longitudinal direction of a sole h 1  of the massagee h is defined as a sole-longitudinal direction U, whereas a direction substantially along a normal direction to the sole surface (longitudinal direction of a calf h 2  of the massagee h) is defined as a sole-normal direction H. The sole-longitudinal direction U and the sole-normal direction H are substantially perpendicular to each other. 
     With respect to the sole-longitudinal direction U, a direction directed from a heel h 3  toward a toe h 4  of the massagee h in the aforesaid feet-resting position is defined as a sole-longitudinally forward direction U 1 , whereas a direction directed from the toe h 4  toward the heel h 3  is defined as a sole-longitudinally rearward direction U 2  (see  FIG. 2 ). 
     With respect to the sole-normal direction H, a direction directed from the sole h 1  toward a knee h 5  of the massagee h in the aforesaid feet-resting position is defined as a sole-normally upward direction H 1 , whereas a direction directed from the knee h 5  toward the sole h 1  is defined as a sole-normally downward direction H 2  (see  FIG. 2 ). 
     Therefore, a transverse direction sy of the chair-type massaging machine  1  is perpendicular to the sole-longitudinal direction U and is also perpendicular to the sole-normal direction H. As shown in  FIG. 7 , the relations between the sole-longitudinal direction U and the vertical direction and between the sole-normal direction H and the vertical direction are varied with the inclination of the footrest  5 . The footrest  5  is capable of pivotally moving from a position where the sole-normal direction H thereof is substantially aligned with the vertical direction (shown in  FIG. 1  and  FIG. 2 ) to a position where the sole-normal direction H thereof is close to the horizontal direction. 
       FIG. 3  is a diagram of a single body of the second segment  5   b  as viewed from above along the sole-normal direction.  FIG. 4  is a diagram of the single body of the second segment  5   b  as viewed from front along the sole-longitudinal direction. As shown in  FIG. 1 ,  FIG. 3  and  FIG. 4 , the second segment  5   b  includes: a pair of second lateral-side walls  5   b   1  upstanding from lateral sides of the footrest and opposing each other; and a second center wall  5   b   2  upstanding from place transversely intermediate between these second lateral-side walls  5   b   1 . 
     As shown in  FIG. 3 , the second lateral-side wall  5   b   1  includes: a rear wall portion  5   c   1  opposing the second center wall  5   b   2 ; and a front wall portion  5   c   2  extended sole-longitudinally forwardly from the rear wall portion  5   c   1  and projected sole-longitudinally forwardly relative to the second center wall  5   b   2 . While the rear wall portion  5   c   1  and the second center wall  5   b   2  (a lateral side thereof) transversely oppose each other, a transverse distance therebetween is progressively decreased toward a sole-longitudinally rear side. A heel-massaging air cell  53 , as a heel massaging portion, is provided at each of the opposing surfaces of the rear wall portion  5   c   1  and the second center wall  5   b   2 . The heel-massaging air cells  53  are adapted to press not only the heel h 3  but also the Achilles tendon of the massagee h as clamping the heel and tendon on the lateral sides thereof. 
     As shown in  FIG. 4  and  FIG. 3 , a plantar-arch projection  5   t  is provided at place corresponding to a sole-normally lower end of the heel-massaging air cell  53  and to a sole-longitudinally front end of the heel-massaging air cell  53 . The plantar-arch projections  5   t  are disposed at places substantially corresponding to the locations of plantar arches h 6  of the massagee h in the aforementioned standard feet-resting position. The lateral plantar-arch projections  5   t  transversely arranged are each configured to project upwardly in the sole-normal direction (see  FIG. 4 ) and hence, are capable of stimulating not only the plantar arches h 6  but also the soles h 1  of the massagee h. The plantar-arch projections  5   t  are supported by a bar-like member  5   g  transversely interconnecting the lateral-side walls  5   b   1  opposing each other. A width of the bar-like member  5   g  with respect to the sole-longitudinal direction is smaller than that of the plantar-arch projection  5   t . In the second segment  5   b , what is present sole-normally downwardly from the soles of the massagee in the above feet-resting position are the plantar-arch projections  5   t  and the bar-like member  5   g . In the second segment  5   b , therefore, an area around the plantar-arch projections  5   t  and on the heel-location side with respect to the feet-resting position is open downward in the sole-normal direction. Furthermore, an area around the plantar-arch projections  5   t  and on the toe-location side with respect to the feet-resting position is open downward in the sole-normal direction. 
     A material of the plantar-arch projection  5   t  is not particularly limited. Usable materials include resins, rubber, metals and the like. 
     As a result of providing the area opened downward in the sole-normal direction, there is defined a second space k 2  which is located around the plantar-arch projection  5   t  and on the heel-location side with respect to the feet-resting position and which extends sole-normally downwardly from the plantar-arch projection  5   t  (a sole-normally lower end thereof p 5 : indicated by a broken line in  FIG. 8 ) (see  FIG. 3  and  FIG. 8 ). In this case, as shown in  FIG. 8(   b ), the massagee h is allowed to insert the heel h 3  into the second space k 2  by varying the angle of ankle (reducing the angle from 90°) or such. In other words, the massagee is allowed to place the heel h 3  sole-longitudinally downwardly from the sole-normally lower end position p 5  of the plantar-arch projection  5   t  (see  FIG. 8(   b )). This leads to an increased freedom of abutting angle and position of the sole relative to the plantar-arch projection  5   t . Thus, the plantar-arch projection  5   t  may provide an even higher massage effect on the sole. In the second segment  5   b , the second space k 2  is not merely provided but the area on the heel-location side with respect to the feet-resting position is open downward in the sole-normal direction. Hence, the area not only provides the aforesaid second space k 2  but also prevents the soles from getting sweaty or prevents dirt and dust separated from the soles from being accumulated in the neighborhood of the plantar-arch projections  5   t . Thus are ensured quite comfortable conditions for sole massage. 
     Because of the provision of the open space, the footrest  5  may be reduced in weight as compared with a case where no open space is provided (such as where the sole support surface of the prior-art document is provided). Therefore, load on a driving device for inclining the footrest  5  (the actuator  6 ) may be reduced, so that the driving device may be reduced in size and weight. 
     The footrest  5  (the second segment  5   b  thereof) is not provided with the sole support surface to support substantially the overall area of the soles of the feet (e.g., the sole support surface of the aforementioned prior-art document). In a case where the sole support surface is provided, the sole h 1  is brought to a high position when the footrest  5  is erected as shown in  FIG. 2 . This raises need for accordingly increasing the height of the whole body of the chair-type massaging machine  1  including the seat surface  3   a . However, the chair-type massaging machine  1  need not provide a margin for the thickness of the sole supporting surface and hence, may be reduced in height as a whole. Thus, the machine can achieve the size reduction. 
     Incidentally, the footrest  5  (the second segment  5   b  thereof) may be provided with a surface confronting the soles. 
     In a case where the footrest  5  (the second segment  5   b  thereof) is provided with the surface confronting the soles, the sole confronting surface may preferably be provided in a manner to define the aforesaid space k 2 . In other words, it is preferred to provide the sole confronting surface at the footrest  5  in a manner not to interfere with the insertion of the heels. 
     In the feet-resting position where the plantar arches h 6  of the massagee h rest on the plantar-arch projections  5   t , as shown in  FIG. 3 , heel-massaging air cells  53  are located at positions to clamp and press the heels h 3 . A first space k 1  is provided at place sole-longitudinally rearwardly of the heels h 3  in the above feet-resting position. With respect to the feet-resting position, the first space k 1  capable of receiving the heels h 3  is provided sole-longitudinally rearwardly of the heels h 3 . This allows the massagee to adjust sole-longitudinal positions of the soles by inserting the heels h 3  in the first space k 1 , and also to place the plantar arches h 6  exactly on the plantar-arch projections  5   t . This also increases the degree of freedom of selecting the positions of massage applied by the heel-massaging air cells  53 . If a space such as the first space k 1  is not provided and hence, the positioning of the soles (positioning with respect to the sole-longitudinal direction) is accomplished by surface-contacting the heels h 3  against an abutment surface disposed sole-longitudinally rearwardly of the heels h 3 , the sole-longitudinal positions of the soles are limited by the position of the heel-abutment surface, so that the plantar arches h 6  of the massagee may sometimes be deviated from the plantar-arch projections  5   t . In this case, the massagee cannot shift the soles rearward in the sole-longitudinal direction. Therefore, the massagee may be unable to press a desired part of each sole against the plantar-arch projection  5   t  or the heels h 3  may be displaced from the positions of massage applied by the heel-massaging air cells  53 . However, the aforementioned arrangement provides an increased degree of freedom of positioning the soles with respect to the sole-longitudinal direction and besides, permits the adjustment of the sole-longitudinal positions of the soles on the basis of the positions of the plantar arches h 6 . Accordingly, the massagee can place the plantar arches h 6  exactly on the plantar-arch projections  5   t . Furthermore, the effect of massage applied by the plantar-arch projections  5   t  and lateral-side air cells  54  is enhanced. 
     As shown in  FIG. 3 , the heel h 3  of human body is configured to be progressively decreased in width toward its end. In addition, the heel-massaging air cells  53  in opposing relation are laid in a manner that a distance therebetween is progressively decreased toward the sole-longitudinally rearward side in order to conform to the configuration of the heel h 3 . Therefore, the pressing force of the heel-massaging air cells  53  for clamping and pressing the heel is directed toward the toe side as inclined relative to the sole-longitudinal direction, thus producing a component force toward the toe. Hence, the heel-massaging air cells  53  clamping the heel h 3  tend to move the heel (or the overall sole) in a manner to push the heel out of the massaging portions. However, the second segment  5   b  of the aforementioned arrangement permits the heel h 3  to be massaged while the concaved plantar arch is pressed against the projected C portion of the plantar-arch projection  5   t . Thus, the physical locking effect of the plantar-arch projection  5   t  prevents the soles from being displaced (moved) toward the toe (sole-longitudinally forwardly) when the heels h 3  are clamped and pressed. Accordingly, the heels h 3  and the plantar arches h 6  may be effectively massaged. 
     If the soles are less prone to move sole-longitudinally forwardly, the massage effect on the calves by means of the first segment  5   a  is also increased. When the soles are displaced sole-longitudinally forwardly, the calves are also displaced in the same direction. Thus, the calves h 2  are displaced from the place between the outer air cells  51  and the center air cells  52 . In this case, therefore, the massage effect on the calves by means of the air cells  51 ,  52  is decreased. As described above, however, the soles are less prone to move sole-longitudinally forwardly and hence, the massage effect on the calves h 2  is also enhanced. 
     Although not shown in  FIG. 1  and the like, a cover member such as formed of cloth or leather is used for covering the air cells provided at the footrest  5 , the air cells including the outer air cells  51 , the center air cells  52 , the heel-massaging air cells  53  and the lateral-side air cells  54 . However, the plantar-arch projections  5   t  are not covered with the cover member but are exposed. Hence, the plantar-arch projections  5   t  directly contact the plantar arches h 6  of the massagee h. In this case, the plantar-arch projections  5   t  are prevented from being flattened due to the cover member and the like covering the plantar-arch projections. Therefore, the physical locking effect of the plantar-arch projections  5   t  is enhanced even further, so that a more effective massage may be applied to the plantar arches h 6  and the heels h 3 . 
     The second segment  5   b  is provided with other air cells besides the heel-massaging air cells  53 . Specifically, the lateral-side air cells  54  principally serving to press “the dorsa of the feet” h 7  of the massagee h are disposed at each of the opposing surfaces of the front wall portion  5   c   2  on the lateral sides. The lateral-side air cell  54  has a bellow-like structure wherein a plurality of air cells overlapped with one another are communicated with one another. As shown in  FIG. 5 , the lateral-side air cell  54  is designed to inflate in a fan shape on a fulcrum defined by a lower side thereof with respect to the sole-normal direction. Thus, the lateral-side air cells  54  are capable of pressing “the dorsa of the feet” h 7  in the feet-resting position where the plantar arches h 6  rest on the plantar-arch projections  5   t.    
     As shown in  FIG. 3 , a sole-longitudinal center position P 1  of the plantar-arch projection  5   t  is included in a sole-longitudinal mounting range W 1  of the lateral-side air cell  54 . Hence, the plantar-arch projections  5   t  in cooperation with the lateral-side air cells  54  can efficiently clamp and massage the feet of the massagee h. In other words, the feet of the massagee h may be efficiently pressed against the plantar-arch projections  5   t  by means of the lateral-side air cells  54 . Thus is further enhanced the massage effect (pressing effect) of the plantar-arch projections  5   t.    
     As shown in  FIG. 3 , a sole-longitudinal center position P 2  of the lateral-side air cell  54  is located sole-longitudinally forwardly of the sole-longitudinal center position P 1  of the plantar-arch projection  5   t . Furthermore, the sole-longitudinal center position P 2  of the lateral-side air cell  54  is located sole-longitudinally forwardly of the uppermost position P 3  or the highest projection point of the plantar-arch projection  5   t  with respect to the sole-normal direction. When the lateral-side air cell  54  is inflated, therefore, a toe-side portion of “the dorsum of the foot” h 7  is pressingly bent downward in the sole-normal direction by the pressing force of the lateral-side air cell  54  in combination with the resultant resistance from the plantar-arch projection  5   t . Accordingly, the aforesaid physical locking effect of the plantar-arch projection  5   t  is even further enhanced, while the effect of acupressure applied by the plantar-arch projection  5   t  is also increased. Thus, the footrest  5  may provide quite an effective massage. 
     The plantar-arch projection  5   t  is adapted to be removably mounted to the bar-like member  5   g . Specifically, the plantar-arch projection  5   t  is mounted to the bar-like member  5   g  by way of a locking projection  5   t   1  which is elastically deformed so as to be fitted on a periphery of the bar-like member  5   g  having a circular section. This facilitates the replacement of the plantar-arch projection  5   t , so that the massagee h may select any favorite one from a variety of plantar-arch projections  5   t  of different specifications including size, configuration, hardness and the like. The bar-like member  5   g  and/or the plantar-arch projection  5   t  may preferably be provided with a locking mechanism (concave/convex, step or the like) for inhibiting the plantar-arch projection  5   t  from being displaced in a longitudinal direction of the bar-like member  5   g . The bar-like member  5   g  and/or the plantar-arch projection  5   t  may further preferably be provided with a locking mechanism (concave/convex, step or the like) for inhibiting the plantar-arch projection  5   t  from being rotated relative to a circumferential direction of the bar-like member  5   g . These locking mechanisms ensure that the plantar-arch projection  5   t  is positively fixed to place and hence, the effect of massage applied by the plantar-arch projection  5   t  is enhanced. 
     Furthermore, the bar-like member  5   g  and/or the plantar-arch projection  5   t  may be provided with an adjustment mechanism for adjusting the fixing position of the plantar-arch projection  5   t  with respect to a transverse direction of the bar-like member. The bar-like member  5   g  and/or the plantar-arch projection  5   t  may also be provided with an adjustment mechanism for adjusting a circumferential position of the plantar-arch projection with respect to the bar-like member  5   g . These adjustment mechanisms permit the massagee h to vary the location of the plantar-arch projection  5   t  as the massagee likes it. Therefore, the effect of massage applied by the plantar-arch projection  5   t  may be enhanced even further.