Patent Publication Number: US-6656140-B2

Title: Massage apparatus having massage rollers mounted to an arm housing which includes improved slider arrangement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation Application of PCT Application No. PCT/JP00/03939, filed Jun. 16, 2000, which was not published under PCT Article 21(2) in English. 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-193025, filed Jul. 7, 1999, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a massage apparatus capable of providing a massage such as pounding and kneading to a user by means of massage rollers. 
     A massage apparatus reciprocating massage rollers along a determined direction and massaging the user&#39;s back by means of the massage rollers is known. In this kind of the massage apparatus, a mattress type capable of providing massage to the overall back of the user while the user lies on his or her back, and a chair type capable of providing massage to parts higher than the waist while the user sits down are known. 
     These massage apparatuses cannot only make the massage rollers run, but also allow them to selectively provide the pounding movement and the kneading movement, in order to enhance the massage effect. 
     To allow the massage rollers to selectively provide the pounding movement and the kneading movement, the massage apparatus is required to adopt a structure capable of certainly making each movement. That is, the massage apparatus must be constituted to be capable of certainly pounding the user by means of the massage rollers when it is to make the pounding movement, and certainly kneading the user by means of the massage rollers when it is to make the kneading movement. 
     In a conventional massage apparatus, a pounding shaft and a kneading shaft are provided to allow the massage rollers to selectively provide the pounding movement and the kneading movement. An eccentric shaft portion is provided on the pounding shaft, and proximal end portions of arms are coupled on the eccentric shaft portion so as to be capable of rotating and oscillating. 
     The massage rollers are rotatably provided on a top side portion of each arm rather than the proximal portion thereof and a slider is further provided on the top side portion so as to freely slide along a determined direction. An eccentric cum body is provided on the kneading shaft and is fitted in a fitting hole formed on the slider. 
     Thus, when the pounding shaft is rotated, the arm rotates with the proximal portion serving as a fulcrum and the massage rollers can thereby make the pounding movement. By rotating the kneading shaft, the arm oscillates and the massage rollers can thereby make the kneading movement. 
     To slidably provide the slider on the arm, however, the structure of sequentially stacking and fixing a slider receiver and a cover on one side surface of the arm through a spacer has been adopted in the conventional massage apparatus. 
     For this reason, the structure of slidably providing the slider on the arm is complicated, the number of parts is increased, much labor is required to the assembly, and thereby the manufacturing costs are increased. 
     In addition, since the massage rollers are rotatably provided on the arm, the support shaft is attached to the arm and the massage rollers are supported on the support shaft. 
     For this reason, much labor is not only required for the attachment of the support shaft, but also the support shaft may become loose due to the use in a long term by attaching the support shaft to the arm by means of, for example, a screw or the like. 
     Moreover, if the slider is simply provided to slide by the slider receiver, the slider becomes loose in accordance with the accuracy in production of the slider or the slider receiver. Therefore, the massage rollers provided on the arm also become loose due to the looseness of the slider and cannot certainly make the pounding movement or the kneading movement. 
     BRIEF SUMMARY OF THE INVENTION 
     This invention aims to provide a massage apparatus which can be easily assembled with a small number of components to have a comparatively simple structure and can be manufactured at small costs, and which allows a slider to be slidably provided on an arm. 
     According to an embodiment of this invention, there is provided a massage apparatus comprising: 
     a holding body for reciprocating along a predetermined direction; 
     a first drive shaft having a pair of eccentric shaft portions at a middle portion thereof, and being provided in the holding body while having an axis substantially perpendicular to a running direction of the holding body; 
     a second drive shaft provided in the holding body while having an axis parallel to the first drive shaft; 
     a pair of eccentric cum bodies each having an eccentric cum portion which is eccentric to a middle portion of the second drive shaft and which has an axis inclined to the axis of the second drive shaft; 
     a pair of arms each having a proximal end portion attached to the eccentric shaft portion of the first drive shaft by a bearing so as to freely oscillate; 
     a pair of main massage rollers provided at two parts on top sides of the respective arms closer than the proximal end portions thereof, so as to freely rotate at a predetermined distance; 
     a slider held to freely slide along a predetermined direction at a part between the pair of main massage rollers of the arms, and fitted in the eccentric cum portions so as to freely rotate, for sliding relatively to the arms interlocking the eccentric rotation of the eccentric shaft portions of the first drive shaft; and 
     a drive mechanism provided in the holding body, for selectively rotating any one of the first and second drive shafts, for assigning pounding movement to the main massage rollers in accordance with the eccentric rotation of the eccentric shaft portions by driving the first drive shaft, and for assigning kneading movement to the main massage rollers in accordance with the eccentric rotation of the eccentric cum bodies by driving the second drive shaft, 
     wherein each of the arms is composed of: 
     an arm housing having a first opening portion; and 
     an arm cover having a second opening portion facing the first opening portion, for forming a holding portion bonded to the arm housing to hold the slider to freely slide along a predetermined direction between the bonding surfaces. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
     FIG. 1 is a plan view showing a massage apparatus from which an exterior cover is removed, according to a first embodiment of the present invention; 
     FIG. 2 is a partially sectional side view showing the massage apparatus; 
     FIG. 3 is a perspective view showing coupling structure of a holding body from which a power box is removed and a belt; 
     FIG. 4 is a plan view showing a drive device and a pair of guide rails; 
     FIG. 5A is a sectional view showing an attachment structure of a base body and the guide rail; 
     FIG. 5B is a plan view showing the guide rail; 
     FIG. 5C is a sectional view showing the guide rail; 
     FIG. 6 is an exploded perspective view showing tension adjusting means; 
     FIG. 7 is partially sectional plan view showing the tension adjusting means; 
     FIG. 8 is a longitudinal sectional view showing the tension adjusting means; 
     FIG. 9 is a front view showing a holding portion of the tension adjusting means; 
     FIG. 10 is a plan view showing a holding body; 
     FIG. 11 is a longitudinal sectional view showing the holding body; 
     FIG. 12 is a side view showing the holding body, illustrating the interior of the power box; 
     FIG. 13 is a plan view showing a state in which the power box of the holding body is separated from a side frame; 
     FIG. 14 is a sectional view showing the power box in the holding body; 
     FIG. 15 is a perspective view schematically showing a second drive mechanism for driving a first drive shaft and a second drive shaft; 
     FIG. 16 is a front view showing a structure of the first drive shaft; 
     FIG. 17 is an enlarged sectional view showing an eccentric cum body provided on the second drive shaft; 
     FIG. 18 is an exploded perspective view showing the arm; 
     FIG. 19 is a front view showing the arm; 
     FIG. 20 is a sectional view as seen along a line XX—XX of FIG. 19; 
     FIG. 21 is a sectional view as seen along a line XXI—XXI of FIG. 19; 
     FIG. 22 is a sectional view as seen along a line XXII—XXII of FIG. 19; 
     FIG. 23 is an enlarged sectional view showing a structure of a slot groove for vertically positioning a slider; 
     FIG. 24 is a front view showing the arm from which an arm cover is removed; 
     FIG. 25A is a plan view showing an arm housing; 
     FIG. 25B is a front view showing the arm housing; 
     FIG. 25C is a sectional view as seen along a line C—C of FIG. 25B; 
     FIG. 26A is a plan view showing the arm cover; 
     FIG. 26B is a front view; 
     FIG. 26C is a sectional view as seen along a line C—C of FIG. 26B; 
     FIG. 26D is an enlarged view showing the slot groove for vertically positioning the slider; 
     FIG. 27A is a front view showing the slider; 
     FIG. 27B is a side view showing the slider; 
     FIG. 28A is a sectional view showing an eccentric cum body; 
     FIG. 28B is a side view showing the eccentric cum body; 
     FIG. 29 is a sectional view showing a cum pressing portion attached to the eccentric cum body; 
     FIG. 30 is an explanatory view showing a mechanism for sensing the rotation angle of the second drive shaft; 
     FIGS. 31A to  31 C are explanatory views showing the rotation angle of the second drive shaft and an inclined state of a pair of arms; 
     FIG. 32 is a side view schematically showing the massage apparatus; and 
     FIG. 33 is a plan view showing a massage apparatus according to a second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of this invention will be explained below with reference to the drawings. 
     FIGS. 1 to  32  show a first embodiment of the present invention. A mattress type massage apparatus shown in FIG. 1 comprises a base body  1  shaped in a rectangular flat plate. The base body  1  is formed of synthetic resin shaped in a flexible sheet and can be bended at a middle part in the longitudinal direction. 
     The base body  1  may be constituted by, for example, a synthetic resin sheet or by superposing a plurality of synthetic resin sheets having different hardness and strength. Further, the base body  1  is not limited to a synthetic resin sheet or a plurality of superposed synthetic resin sheets, but may be constituted in a framework structure or the like. The base body  1  is not limited at all to the structure, type, material or the like. 
     A pair of guide rails  4  molded of nylon (name of an article) or synthetic resin such as polypropylene are mounted in parallel, remote from one another, at both end parts in the lateral direction on the top surface of the base body  1 . Each of guide rails  4  has a strip-shaped base portion  4   a  and L-shaped support portions  4   b  are formed on both ends in the lateral direction of the base portion  4   a  as shown in FIGS. 5A to  5 C. A pair of L-shaped elements  4   c  project from each of upper and lower surfaces of a middle part of the base portion  4   a , so as to face one another. Thus, a passage  4   d  is formed on each of upper and lower surfaces of the base portion  4   a  and a side of the upper passage  4   d  serves as a running surface  4   e  of wheels  114  as described later. 
     The guide rail  4  is held by a plurality of holding members  4   f  to be able to slide on the top surface of the base body  1 . That is, each of holding members  4   f  is substantially formed in a bracket shape as shown in FIG. 5A. A middle part of the holding member  4   f  is bonded on the lower surface of the base body  1 . Engagement portions  4   g  bent in an L shape at both ends of the holding member  4   f  project from a pair of openings la formed on the base body  1  toward the top surface of the base body  1  and engage with the support portions  4   b  of the guide rail  4 . Thus, the guide rail  4  is held to be able to slide on the base body  1 . 
     A plurality of slits  4   h  are formed with a predetermined distance disposed therebetween, at one or two portions of the middle part of the guide rail  4  other than the base portion  4   a  as shown in FIGS. 5B and 5C. For this reason, the guide rail  4  can be bended together with the base body  1  at the slits  4   h.    
     Cushion members  5  formed of an elastic material such as urethane foam are provided at the outer side and one longitudinal end side, respectively, on the top surface of the base body  1 . 
     As shown in FIG. 1, a drive device  10  is provided as a first drive mechanism, on the top surface of one longitudinal end side of the base body  1 , i.e. at one side end of the guide rails  4 . The drive device  10  has a casing  11  as shown in FIGS. 2 and 4. A drive source  12  in which a speed reducer and a motor are integrally constituted is provided in the casing  11 . The drive source  12  allows a pair of gears  13 , which are provided on each side of the casing  11 , to be rotated in opposite directions. A drive pulley  14  is provided integrally with each of the gears  13 . 
     As shown in FIG. 2, end portions of a belt  15 , which serves as a power transmission member composed of a metal strip such as stainless steel, are wound round the paired drive pulleys  14 , respectively. The middle parts of the belt  15  pass through the upper and lower passages  4   d  of the guide rail  4  and are hooked on a follower roller  16 , which is provided to be freely rotatable on the other end of the guide rail  4 . 
     When the drive source  12  is operated to drive the paired gears  13  in opposite directions, the belt  15  is paid out from the drive pulley  14  of one of the gears  13  and wound round the drive pulley  14  of the other gear  13 . The belt  15  is thereby driven to run along the passages  4   d.    
     In FIG. 2, for example, if one of the drive pulleys  14  is rotated in a direction of an arrow X and the other drive pulley  14  is rotated in a direction of an arrow Y, the part of the belt  15  passing through the upper passage  4   d  is driven to run in a direction represented by an arrow Z. 
     As shown in FIG. 4, a running range setting mechanism  17  for reciprocating the belt  15  within a certain running range is provided in the casing  11 . The running range setting mechanism  17 , for example, detects the running distance of the belt  15  in accordance with the number of rotations of the drive pulleys  14  and the like and changes the direction of the rotation of the gears  13  made by the drive source  12  in accordance with the detection signal, though not shown in detail. The belt  15  thereby reciprocates within a certain running range. 
     A holding body  21  driven to run by the belt  15  is provided between the paired guide rails  4  as shown in FIG.  1 . The structure of the holding body  21  will be explained later. The top side of the holding body  21 , i.e. the top side of the base body  1  is covered by an exterior cover  20  as shown in FIG. 32, such that the user lies on the exterior cover  20 . 
     Tension adjusting means  41  for controlling the tension of the belt  15  are provided at the end of the paired guide rails  4 , which is positioned on the side of the drive device  10  as shown in FIG.  1 . Each of the tension adjusting means  41  has a holding member  42  obtained by bending a plate to make the side surface thereof shaped substantially in a bracket as shown in FIGS. 6 to  9 . 
     The holding member  42  is provided with the back wall bonded to the casing  11  of the drive device  10 . A guide member  43  is provided on a top surface of the bottom part of the holding member  42 . Guide grooves  44  are formed at both sides of the guide member  43  by bending the guide member  43  in a shape of a mountain having a strip-shaped member. The lower ends of both side of the guide member  43  are fixed on the top surface of the bottom part of the holding member  42 . A bracket-shaped cutaway portion  45  is formed on the middle part of the guide member  43 . 
     A slide member  46  is supported by the holding member  42  so as to be freely slidable. The slide member  46  is formed by bending a strip plate like member such that its plane surface is shaped substantially in a bracket. The middle part of the slide member  46  is formed to be lower than the middle part where the cutaway portion  45  of the guide member  43  is formed. 
     Both side edges of the slide member  46  are inserted into the guide groove  44  so that the slide member  46  can slide freely therein. That is, the slide member  46  is guided in the guide groove  44  and can slide along the top surface of the bottom part of the holding member  42 . 
     A proximal end of each side edge of the slide member  46  is bent in an L letter as a support element  47 . A spring  48  serving as an elastic member is provided between the support element  47  and the back wall of the holding member  42 . That is, as shown in FIG. 7, one end of the spring  48  is held by a pin  49  provided at the support element  47  and the other end thereof is made to abut on the back wall of the holding member  42 . 
     Openings  42   a  and  11   a  are formed at positions corresponding to one another, respectively, on the back wall of the holding member  42  and the casing  11  of the drive device  10  on which the back wall is bonded, as shown in FIGS. 6 and 8. The belt  15  is inserted through the openings  42   a  and  11   a.    
     One end surface of the guide rail  4  abuts on the middle part of the slide member  46 . In this state, the tension of the belt  15  is applied the guide rail  4  in the direction represented by an arrow A in FIG. 1, the guide rail  4  slides in the direction of the arrow A by the tension, and the spring  48  is thereby compressed. That is, the guide rail  4  is held on the base body  1  to be elastically slidable by the spring  48 . 
     Thus, if the length of the guide rail  4  longitudinally extends or contracts by the variation in the temperature or the like, the guide rail  4  slides while elastically displacing the slide member  46  of the tension adjusting means  41  in accordance with the extension and contraction and, therefore, the tension occurring at the belt  15  can be constantly maintained. 
     That is, when the guide rail  4  extends, it is possible to prevent the stress more than the necessary one from being applied to the guide rail  4 . When the guide rail  4  contracts its length, it is possible to prevent the belt  15  from being loose. It is also possible to absorb the extension and contraction of the guide rail  4  caused by the difference in the diameters of the winding of the drive pulleys  14 . 
     The holding body  21  has a pair of side frames  112  formed of synthetic resin in a shape of a casing, with the lower surface opening, as shown in FIGS. 10 to  12 . The bottom parts of both end portions in the running direction of the paired side frames  112  are coupled by coupling shafts  113 , respectively. 
     Guide rollers  114  running on the running surfaces  4   e  formed on the guide rails  4  are provided respectively at both end portions of each of the paired coupling shafts  113  so as to be freely rotatable. A center frame  115 , which has a side surface having a rectangular shape, is fixed at the middle portions of the coupling shafts  113  along the running direction of the side frames  112 . 
     A holding member  115   a  is attached to the lower end of the middle part on the outer surface of the side frame  112  as shown in FIG. 12. A middle part of a wire  116  is inserted through the holding member  115   a  and thereby fixed. Both end portions of the wire  116  are led along the direction of the side portion of the side frame  112  and coupled to the belt  15  via coupling portions  117 . The terminals of the end portions are coupled and fixed to the coupling shaft  113 . 
     Thus, the holding body  21  interlocks the belt  15  via the wire  116  by driving the belt  15  to run. That is, the holding body  21  reciprocates along the guide rail  4 . 
     As shown in FIG. 10, an electric component box  121  is attached to the outside surface of one of the side frames  112  so as to be freely detachable therefrom and a power box  122  is also attached to the outside surface of the other side frame  112  so as to be freely detachable therefrom. A first drive shaft  123  is rotatably provided at a lower part of one end side in the running direction, between the paired side frames  112  of the holding body  21 , and a second drive shaft  124  is also rotatably provided at an upper part of the middle portion of the holding body  21 . 
     The power box  122  is composed of a main body portion  122   a  whose side surface positioned at the laterally inner side of the holding body  21  is opened, and a lid portion  122   b  fixed bonded to the opening surface and fixed by screws  122   c . The main body portion  122   a  is formed of aluminum die-casting or the like having a comparatively high heat conductivity, and the lid portion  122   b  is formed of synthetic resin. 
     The first drive shaft  123  is divided into a first portion  123   a  and a second portion  123   b  at the middle part in the longitudinal direction of the shaft as shown in FIG. 16. A first eccentric shaft portion  124   a  and a second eccentric shaft portion  124   b  are provided at the first portion  123   a  and the second portion  123   b , respectively. The eccentric shaft portion  124   a  and the eccentric shaft portion  124   b  are coupled while eccentric phases thereof are shifted from one another at 180 degrees by a joint  125 , which connects top end portions of the eccentric shaft portion  124   a  and the eccentric shaft portion  124   b . The joint  125  is rotatably supported at the center frame  115  by a first bearing  126 . 
     Further, a proximal end portion of an arm  127  whose side surface is shaped in an L letter is coupled to each of the eccentric shaft portions  124   a  and  124   b  by a second spherical bearing  129  so as to be freely rotatable and slidable. That is, a pair of arms  127  are provided symmetrically around the center of the lateral direction of the holding body  21 . 
     As shown in FIG. 18, the arm  127  is composed of an arm housing  132  at which a first rectangular opening portion  131  is formed, and an arm cover  135  at which a second rectangular opening portion  133  is formed and which is bonded and fixed on one side surface of the arm housing  132  by screws  134 . The arm housing  132  and the arm cover  135  are formed of synthetic resin such as polyacetals and the like. 
     A pair of support shafts  136  are molded to project integrally with a certain distance disposed therebetween, on the other side surface of the middle part and the top end part of the arm housing  132 , i.e. on the part closer to the end than the proximal part when the proximal part is attached to the eccentric shaft portions  124   a  and  124   b.    
     A main massage roller  137 , which has a plurality of semi-spherical projections  137   a  are provided on an outer peripheral surface thereof along the peripheral direction, is provided to be freely rotatable on the paired support shafts  136  via a bush  138  divided into two pieces, as shown in FIG.  21 . The support shaft  136  passes into the main massage roller  137  and the main massage roller  137  is held by an attachment screw  141  engaged with a screw hole  139  formed on the arm cover  135  so as not to be detached from the support shaft  136 . 
     Since the paired support shafts  136  are molded integrally with the arm housing  132  and the main massage rollers  137  are attached to the support shafts  136 , the attachment to the support shafts  136  can be executed more easily than the other components. In addition, since the support shafts  136  are not loose to the arm housing  132 , the main massage rollers  137  can be strictly attached. 
     A holding portion  142  is formed between the surfaces of the arm housing  132  and the arm cover  135  as shown in FIGS. 22 and 23. A slider  143  is provided at the holding portion  142  so as to be freely slidable along the separating direction of the paired main massage rollers  137 , i.e. the lateral direction. 
     As shown in FIGS. 27A and 27B, the slider  143  is a rectangular metal plate. Guide elements  144  project from top and bottom end surfaces and both side surfaces of the slider  143 . The guide elements  144  are slidably contained in recess portions  145  formed on both sides, and upper and lower ends of the first opening portion  131  on one side surface of the arm housing  132 , as shown in FIG.  24 . 
     A pair of strip-like receiving portions  146 , which enter the lower parts of the recess portions  145  formed on both sides of the first opening portion  131  of the arm housing  132 , are integrally formed to project, on the inner surface of the arm cover  135 , as shown in FIGS. 23,  26 A and  26 B. 
     First slot grooves  147  are formed on the receiving portions  146  as shown in FIGS. 23 and 26D. Screw holes  148  for communicating with the first slot grooves  147  are formed on the arm cover  135 , and first deformation screws  149  (FIG. 18) are engaged with the screw holes  148 . 
     When the first deformation screw  149  is engaged with the receiving portion  146 , upper and lower parts of the receiving portion  146  divided by the first slot groove  147  expand in the vertical direction and pressurize the lower surface of the guide element  144  at the side of the slider  143 . Thus, the vertically loose condition of the slider  143  in the holding portion  142  can be prevented. 
     Further, a second slot groove  151  is formed on each of the top and bottom end sides of the second opening portion  133  as shown in FIGS. 26A and 26C. Screw holes  152  for communicating with the second slot grooves  151  from the outer surface of the arm cover  135  are formed on the arm cover  135 . 
     Second deformation screws  153  are engaged with the screw holes  152 . Thus, the parts of the arm cover  135  at which the second slot grooves  151  are formed expand inwardly and pressurize the guide elements  144  provided on the upper and lower sides of the slider  143 . Therefore, it is possible to prevent the slider  143  from being loose in the direction of thickness intersecting the sliding direction. 
     That is, the slider  143  is provided to be freely slidable without being loose in the longitudinal direction and the direction of thickness, by the first deformation screws  149  and the second deformation screws  153 . 
     As shown in FIGS. 25A and 25B, oil storing grooves  132   a  are formed on the inner surfaces of the recess portions  145  formed on both side ends and the upper and lower ends of the first opening portion  131  of the arm housing  132 . As shown in FIGS. 26A and 26B, oil storing grooves  135   a  are formed at parts facing the recess portions  145 , on the inner surface of the arm cover  135 . Lubricating oil is supplied into the oil storing grooves  132   a  and  135   a.    
     Thus, the slider  143  provided to be slidable on the holding portion  142  can smoothly slide for a long time. 
     A fitting hole  154  is formed on the slider  143 . The middle part of the second drive shaft  124  is inserted through the fitting hole  154 . An eccentric cum body  155  is mounted on the middle part of the second drive shaft  124 . 
     A boss portion  156  and an eccentric cum portion  157  are integrally formed by synthetic resin on the eccentric cum body  155  as shown in FIG. 28. A shaft hole  158  is formed at the eccentric cum body  155 , and the second drive shaft  124  is inserted through the shaft hole  158 . A key  159  is provided between the shaft hole  158  of the eccentric cum body  155  and the second drive shaft  124  as shown in FIG.  17 . 
     The eccentric cum portion  157  is eccentric to the axis of the second drive shaft  124  and is inclined at a predetermined angle as shown in FIG. 28. A collar portion  161  is formed on one side of the eccentric cum portion  157 . The eccentric cum portion  157  is engaged with the fitting hole  154  through a thrust washer  160  (FIG.  18 ). 
     A cum pressing member  162  of synthetic resin is bonded and fixed to an end surface of the eccentric cum portion  157 . The slider  143  is sandwiched between the cum pressing member  162  and the collar portion  161 . The cum pressing member  162  is formed to have a diameter greater than the diameter of the eccentric cum portion  157 . 
     A recess portion  163 , which opens to the end surface of the eccentric cum portion  157 , is formed on the end surface thereof as shown in FIGS. 28A and 28B. A projecting portion  164 , which is fitted in the recess portion  163 , is provided on the cum pressing member  162  as shown in FIG.  29 . 
     Split grooves  165  are formed along the longitudinal direction of the shaft, on the peripheral wall of the recess portion  163  of the eccentric cum portion  157 . A third slot groove  166  is formed in the projecting portion  164 . Further, a screw hole  167  communicating with the third slot groove  166  is formed in the cum pressing member  162 . A third deformation screw  168  is engaged with the screw hole  167  as shown in FIG.  17 . 
     Thus, the projecting portion  164  expands laterally, presses the peripheral wall of the recess portion  163  which is split by the split grooves  165 , outwardly in the radial direction, and makes the peripheral wall contact the inner peripheral surface of the fitting hole  154  of the slider  143 . Therefore, the eccentric cum body  155  can be fitted in the fitting hole  154  of the slider  143  without being loose. 
     The second drive shaft  124  is driven to rotate as described later. Then, the paired main massage rollers  137  revolve vertically in accordance with the eccentricity and the angle of inclination of the eccentric cum body  155 , and the arm  127  pivots in the direction represented by an arrow in FIG.  10 . For this reason, the paired main massage rollers  137  provided on each arm  127  execute the kneading movement. 
     At this time, since the slider  143  slides to the arm  127  in accordance with the eccentric rotation of the eccentric cum portion  157 , the pivoting movement of the paired arms  127  is smoothly executed. 
     At the upper part of the arm housing  132  of the arm  127 , a covering portion  168  for covering the upper side of the eccentric cum body  155  projecting from the opening portion  131  is provided. Thus, it is possible to prevent the user&#39;s body from abutting on the eccentric cum body  155 . 
     On the second drive shaft  124 , a pair of center rollers  171  positioned at both sides of the center frame  115 , a pair of side rollers  172  positioned in the vicinity of the inner surfaces of the respective side frames  112 , and a pair of auxiliary massage rollers  173  contained in container portions  112   a  formed to open to the upper surface of the side frames  112 , are provided to be freely rotatable, as shown in FIGS. 10 and 11. A plurality of projections  173   a  in a semi-columnar shape are provided on the outer peripheral surface of the auxiliary massage rollers  173 , in the peripheral direction. 
     The center rollers  171  prevent the user&#39;s body, particularly the neck from abutting on the center frame  115 , and the side rollers  172  prevents the neck from abutting on the inner edges of the side frames  112 . Further, the semi-columnar projections  173   a  of the auxiliary massage rollers  173  are formed in a taper shape which is inclined downwardly to the inside of the holding body  21  in the lateral direction. It is thereby possible to massage the user&#39;s back, prevent the user&#39;s body from displacing in the lateral direction by the tapered surface, and prevent the body from abutting on the top surfaces of the side frames  112 . 
     The main massage rollers  137  and the auxiliary massage rollers  173  are formed by foaming urethane resin. Thus, the massage rollers  137  and  173  are set to have a predetermined hardness by adjusting the magnification of foaming at the foaming time. In this embodiment, the hardness of the massage rollers  137  and  173  is set to be in a range from 20 to 50, preferably 30 to 50, as measured by a rubber hardness meter adopting the spring type hardness test A based on the JIS physical testing method of vulcanized rubber. 
     An end portion of the first drive shaft  123  and an end portion of the second drive shaft  124  project into the power box  122 . A second drive mechanism  181  is provided inside the power box  122 . The first drive shaft  123  and the second drive shaft  124  are selectively driven to rotate by the second drive mechanism  181 . 
     The second drive mechanism  181  has a reversible motor  182  contained in the power box  122  as shown in FIGS. 12 and 13. A rotating shaft  185  provided to be freely rotatable inside the power box  122  is coupled to an output shaft  183  of the reversible motor  182  via a joint  184 . 
     A first worm gear  186  and a second worm gear  187  are provided on the rotating shaft  185 . As shown in FIG. 15, the first worm gear  186  can be rotated in one way by a first one-way clutch  188  and the second worm gear  187  can be rotated in the way opposite to the way of rotation of the first worm gear  186  by a second one-way clutch  189 . 
     A first worm wheel  191  engages with the first worm gear  186 . The first worm wheel  191  is attached to a first support shaft  192  provided to be freely rotatable at one end inside the power box  122 . 
     An end portion of the first support shaft  192  is coupled to a coupling  193  provided to be freely rotatable on the sidewall of the power box  122 , as shown in FIG.  13 . The coupling  193  faces a through hole  194  formed on the sidewall. 
     When the power box  122  is bonded to one of the side frames  112 , one end portion of the first drive shaft  123  enters the power box  122  through the through hole  194  and is coupled to the first support shaft  192  via the coupling  193  to rotate integrally therewith. This coupling can be implemented by, for example, forming splines on the inner peripheral surface of the coupling  193  and also forming splines  123   c  on the end portion of the first drive shaft  123  as shown in FIG.  13 . 
     Therefore, the one-way rotation of the output shaft  183  of the reversible motor  182  is transmitted to the first drive shaft  123  via the first worm gear  186  and the worm wheel  191 . The first worm gear  186  and the worm wheel  191  constitute a first power transmission mechanism. 
     A second worm wheel  194  engages with the second worm gear  187 . The second worm wheel  194  is attached to the end portion of a second support shaft  195  supported to be freely rotatable inside the power box  122 . The other end portion of the second support shaft  195  projects into a recess portion  196  formed on one side of the power box  122  and the projecting end portion is fitted in a first helical gear  197 . 
     A second helical gear  198  engages with the first helical gear  197 . The second helical gear  198  is provided to be freely rotatable and slightly move in the longitudinal direction of the shaft, on a third support shaft  199  which projects from the outer surface of the sidewall of the power box  122  forming the recess portion  196 . 
     An intermediate gear  201  composed of a helical gear formed integrally with the second helical gear  198  is provided on the third support shaft  199 . A stopper  202  such as a C ring and a wave washer  203  are provided at the tip end of the third support shaft  199  and the second helical gear  198  is pushed by the wave washer  203  in the longitudinal direction of the shaft. 
     When the power box  122  is bonded to the side surface of one of the side frames  112 , the intermediate gear  201  enters a recess portion  204  formed on the side surface of the side frame  112 . An end portion of the second drive shaft  124  projects into the recess portion  204  and the projecting end portion is fitted in a terminal gear  205 , which is composed of a helical gear. The intermediate gear  201  engages with the terminal gear  205 . 
     Thus, when the rotating shaft  185  is driven to rotate in the way opposite to the one way as described above by the reversible motor  182 , the rotation is transmitted to the second drive shaft  124  via the second worm gear  187 , the second worm wheel  194 , the first and second helical gears  197  and  198 , the intermediate gear  201  and the terminal gear  205 . 
     These gear rows that transmit the power to the second drive shaft  124  constitutes a second power transmission mechanism. With this constitution, the transmission of the power to the second drive shaft  124  can be implemented certainly in a simple structure, and it is possible to reduce the speed at two stages and coaxially arrange the second support shaft  195  and the second drive shaft  124 . Particularly, the number of components can be reduced by integrally forming the second helical gear  198  and the intermediate gear  201 . 
     A spring clutch  206  serving as a third one-way clutch is provided at the other end portion, i.e. the end portion projecting into the other side frame, of the first drive shaft  123 , as shown in FIGS. 10 and 16. When the first drive shaft  123  does not rotate, the spring clutch  206  restricts the first drive shaft  123  from rotating in a way opposite the one way, which is the rotating way of the first drive shaft  123 . 
     Further, a sheet-like friction member  207 , which is formed of a material such as polyacetals, is applied to one side surface of the second helical gear  198 . The friction member  207  is in small contact with an outer surface (fixed member) of the sidewall of the recess portion  196  at the power box  122 . 
     The load in the longitudinal direction of the shaft is applied to the second helical gear  198  engaging with the first helical gear  197  driven to rotate by the reversible motor  182 , in the direction of being remote from the outer surface of the sidewall, in accordance with the facing way of the gear teeth. However, the load in the direction opposite thereto is applied to the second helical gear  198  by the wave washer  203  and, therefore, the friction member  207  provided at the second helical gear  198  is kept to be in a small contact with the outer surface of the sidewall. 
     The friction member  207 , which is pushed on the outer surface of the sidewall, reduces the speed of the rotation of the second drive shaft  124 . That is, in a case where the eccentric cum body  155  rotates in synchronization with the rotation of the second drive shaft  124 , it gradually rotates against the user&#39;s load applied to the main massage roller  137  when it comes from the bottom dead center of eccentric cum portion  157  to the top dead center thereof. 
     However, when the eccentric cum body  155  passes the top dead center, it is to radically rotate since the user&#39;s load is applied to the eccentric cum body  155  via the main massage roller  137 . At this time, the rotation of the second drive shaft  124  interlocking with the rotation of the eccentric cum body  155  is transmitted to the second helical gear  198  in the direction opposite to the direction of power transmission from the first helical gear  197 . 
     When power is transmitted from the first helical gear  197  to the second helical gear  198 , the load in the longitudinal direction is applied to the second helical gear  198  in the direction of being remote from the outer surface of the sidewall. However, in a case where the rotation of the second drive shaft  124  is transmitted in the opposite direction, the load in the longitudinal direction of approaching the outer surface of the sidewall is applied to the second helical gear  198 . Further, since the second helical gear  198  is pushed toward the sidewall by the wave washer  203 , the second helical gear  198  slightly moves along the third support shaft  199  and the friction member  207  provided on the side surface thereof is pushed on the outer surface of the sidewall of the recess portion  196 . 
     Accordingly, since the second drive shaft  124  is prevented from rotating radically, the main massage roller  137  is prevented from radically falling together with the arm  127  and thus preferable massaging can be obtained. 
     Electricity is fed to the reversible motor  182  provided in the power box  122  of the holding body  21  and also to an electric component  208  (FIG. 10) provided in the electric component box  121  via a pair of belts  15  driven to run under the holding body  21 . 
     That is, as shown in FIG. 6, a pair of holders  212  (one of them shown) having conductive brushes  221 , which are in electric contact with the belts  15 , are fixed on the end portions of the paired guide rails  4  by screws  213 . Lead wires  214  are connected to the conductive brushes  221 . One of the lead wires  214  is connected to the positive side of the DC power supply (not shown) and the other is connected to the negative side thereof. 
     Each of the belts  15  is electrically conductive with the side frame  121  of the holding body  21  via the coupling portions  117  and the wire  116  that make the holding body  21  interlock with the belt  15 , as shown in FIG.  3 . 
     Both ends of the wire  116  are fixed to the ends of the paired coupling shafts  113  connected to the paired side frames  121 , by nuts  220 . The nut  220  provided at one end of one of the coupling shafts  113  and the nut  221  provided at the other end of the other coupling shaft  113  are formed of an electrically insulating material such as synthetic resin or the like. The other nuts  220  are formed of a metal, which is an electrically conductive material. 
     Thus, one of the belts  15  is electrically connected to the coupling shaft  113  via the metal nuts  220  provided at one end of one of the wires  116  and one end of the coupling shaft  113 . The other belt  15  is electrically connected to the other coupling shaft  113  via the metal nuts  220  provided at one end of the other wire  116  and one end of the other coupling shaft  113 . 
     As shown in FIG. 10, one end of one of the coupling shafts  113  and the reversible motor  182  are connected to one another by a first lead wire  222 , and one end of the other coupling shaft  113  the reversible motor  182  are connected to one another by a second lead wire  223 . 
     The other end of the above one coupling shaft  113  and the electric component  208  provided in the electric component box  121  are connected to one another by a third lead wire  224 , and the other end of the other coupling shaft  113  and the electric component  208  are connected to one another by a fourth lead wire  225 . 
     Thus, electricity is fed to the reversible motor  182  and the electric component  208 . That is, even when the reversible motor  182  is provided in the holding body  21  driven to run which allows the main massage roller  137  to make kneading and pounding movements, electricity can be fed to the reversible motor  182  by using the belts  15  which make the holding body  21  run. 
     A sensor mechanism  225  for sensing the eccentric position of the eccentric cum portion  157  of the eccentric cum body  155  is provided at the other end portion of the second drive shaft  124 , which projects into the electric component box  121 . The sensor mechanism  225  has a disk  226  in which the end portion of the second drive shaft  124  is fitted as shown in FIG. 30. A magnet  227  is embedded in the disk  226 , corresponding to the position (top fulcrum) where the eccentricity of the eccentric cum portion  157  is largest. 
     First to third sensors  228   a  to  228   c  for sensing the magnetic force are arranged around the disk  226 , and shifted at 90 degrees in the peripheral direction. That is, the sensors are arranged vertically and one of the directions at right angles with the vertical direction. When the magnet  227  faces the sensors  228   a  to  228   c , they sense the magnetic force thereof. Therefore, they can sense the rotation angle corresponding to the eccentricity of the eccentric cum portion  157 . Thus, the rotation angle of the second drive shaft  124  can be controlled at an angle at which the magnet  227  faces each of the sensors  228   a  to  228   c.    
     The arms  127  pivot by the rotation of the second drive shaft  124 . By controlling the rotation angle, the pivoting state as seen in the plane of the paired arms  127  can be set to be open at the top, open at the back or parallel, as shown in FIGS. 31A to  31 C. 
     The above-described embodiment employs the sensors of the magnetic force type using the magnets. However, the sensors of the photoelectric type may be employed. 
     Next, use of the massage apparatus having the above-described structure will be explained. 
     When the user lies down on the exterior cover  20  that covers the holding body  21  on the base  1 , the drive device  10  is operated. Thus, since the holding body  21  reciprocates along the rails  2 , massaging can be provided to the user&#39;s back by the main massage rollers  137  and the auxiliary massage rollers  173  provided in the holding body  21 . 
     Two main massage rollers  137  are provided at each of a pair of arms  127 . Therefore, the massaging force is larger than that in a case where only one massage roller  137  is provided thereat, and in accordance with this the massaging effect can be enhanced. 
     Two main massage rollers  137  are provided on one arm  127  along the running direction of the holding body  21 , with a predetermined distance disposed therebetween. The user&#39;s body hardly falls in that direction. In addition, the user&#39;s body hardly falls in the lateral direction of the holding body  21  by providing the auxiliary massage rollers  173  outside the main massage rollers  137 . Further, the center rollers  171  are provided on the second drive shaft  124 , on both sides of the center frame  115  and the side rollers  172  are provided thereon on the inner side of the side frames  112 . Further, the cover portion  168  for covering the eccentric cum body  155  provided at the arm  127  is provided on the arm  127 . 
     Therefore, these rollers and the cover portion  168  prevent the body of the user lying on the base  1  from falling into the holding body  21 . Therefore, the use&#39;s body is not strictly rubbed by the holding body  21  driven to run. Further, since it is possible to prevent the user&#39;s body from abutting on the holding body  21  without making the diameter of the massage roller  31  larger, the thickness of the massage apparatus is not increased. 
     The main massage rollers  137  and the auxiliary massage rollers  173  are formed by subjecting urethane resin to foam molding. For this reason, they have a desirable hardness and an outer skin is formed on the surface thereof by setting the magnification of foaming at the foam molding time. Therefore, the abrasion resistance can be improved by this outer skin. Further, since they have a desirable harness in accordance with the foaming rate, a plasticizer does not need to be used as the prior art. The massage rollers  137  and  173  having high abrasion resistance can be therefore obtained. 
     In this embodiment, the hardness of the massage rollers  137  and  173  is set to be in a range from 20 to 50, preferably 30 to 50, as measured by a rubber hardness meter adopting the spring type hardness test A based on the JIS physical testing method of vulcanized rubber. 
     Thus, the massage rollers  137  and  173  are not too hard to give pain to the user or not too soft to achieve the massaging effect. 
     Two main massage rollers  137  are provided at the middle portion and the top end portion of the arm  127 , that are closer to the head side than the proximal end part, and are supported on the second drive shaft  124  by means of the slider  143  that is held to be freely slidable at the middle part of the arm  127 . 
     Therefore, if the first drive shaft  123  is driven to make the main massage rollers  137  execute the pounding movement while the user&#39;s load is applied to the main massage rollers  137 , the rotation moment occurs at the arm  127  around the second drive shaft  124  serving as a fulcrum, as a difference between a product of the distance from the center of the drive shaft  124  to the attachment portion of the main massage roller  137  provided at the top end portion and the load applied to the main massage roller  137  at the top end portion, and a product of the distance from the center of the drive shaft  124  to the attachment portion of the main massage roller  137  provided at the middle portion and the load applied to the main massage roller  137  at the middle portion. 
     To drive the first drive shaft  123 , the torque obtained by dividing the value of the rotation moment occurring at the arm  127  by the distance from the second drive shaft  124  serving as the fulcrum to the first drive shaft  123  may be applied to the first drive shaft  123 . 
     That is, the first drive shaft  123  can be driven by a small power as compared to a case where one main massage roller  137  is provided on the top end side of the arm  127 . In a case where the second drive shaft  124  is driven to make the kneading movement, too, it can be driven by a small torque. For this reason, the reversible motor  182  for driving the first and second drive shafts  123  and  124  can be miniaturized. 
     On the other hand, if the reversible motor  182  provided in the holding body  21  is operated to rotate the rotating shaft  185 , for example, one direction (normal direction), only the first drive shaft  123 , of the first and second drive shafts  123  and  124 , can be rotated in a determined direction. 
     Thus, the paired arms  127  can be vertically displaced by the eccentric rotation of the first eccentric shaft portion  124   a  and the second eccentric shaft portion  124   b  of the first drive shaft  123 . Therefore, the pounding movement can be assigned to the main massage rollers  137 . 
     If the rotating shaft  185  is rotated in a reverse direction by the reversible motor  182 , only the second drive shaft  124  is rotated. The arms  127  are thereby driven to pivot and, therefore, the kneading movement can be assigned to the main massage rollers  137  provided on the paired arms  127 . 
     The pounding and kneading movements can be made by the main massage rollers  137  while reciprocating the holding body  21 . That is, since the drive device  10  is provided in the base  1  and the reversible motor  182  is provided in the holding body  21 , either the pounding movement or the kneading movement can be selectively assigned to the main massage rollers  137  while making the holding body  21  run if both the drive device  10  and the reversible motor  182  are operated. 
     If the drive device  10  is operated in a state in which the operation of the reversible motor  182  is stopped, the holding body  21  can be made to run and rolling massage can be thereby provided by the main massage rollers  137 . In addition, if the reversible motor  182  is operated while the operation of the drive device  10  is stopped, either the pounding movement or the kneading movement can be assigned to the main massage rollers  137 . Thus, two main massage rollers  137  are provided on each of the paired arms  127  and, therefore, the pounding movement and the kneading movement can be made at four points and preferable massaging can be effectively provided. 
     Reversibly, if either the drive device  10  or the reversible motor  182  is operated, either the pounding movement or the kneading movement can be assigned to the main massage rollers  137  when the holding body  21  is made to run or while the operation of the holding body  21  is stopped. 
     The reversible motor  182  and the second drive mechanism  181  for selectively rotating the first drive shaft  123  and the second drive shaft  124  by the reversible motor  182  are provided in the power box  122  of the holding body  21 . 
     For this reason, the overall structure can be made compact as compared to a case where the reversible motor  182  is provided separately from the holding body  21 . Moreover, although the reversible motor  182  is provided in the holding body  21  driven to run, electricity can be fed to the reversible motor  182  by means of a pair of belts  15  for allowing the holding body  21  to run and, therefore, the structure for the feeding can also be simplified. 
     The spring clutch  206  is provided at the end portion of the first drive shaft  123  which projects into the electric component box  121 . When the first drive shaft  123  is stopped, the spring clutch  206  restricts the first drive shaft  123  from rotating in a direction opposite to the above-described determined direction. 
     When the first drive shaft  123  is stopped and then the second drive shaft  124  is rotated to allow the main massage rollers  137  to make the kneading movement, the first drive shaft  123  sometimes rotates slightly in the direction opposite to the determined direction of rotation in accordance with the movement of the pivoting arms  127 . Then, the vertical movement around the proximal end part serving as a fulcrum is applied to the arms  127  as well as the pivoting movement made by the second drive haft  124  and, therefore, preferable kneading massage cannot be made. 
     However, the spring clutch  206  restricts the rotation of the first drive shaft  123 , which is caused by the pivoting movement of the arms  127  made by the second drive shaft  124 . The spring clutch  206  also prevents the vertical movement around the proximal end part serving as a fulcrum caused by the first drive shaft  123  when the arms  127  are pivoted by the second drive shaft  124 . 
     That is, it is possible to prevent the pounding movement from being made during the kneading movement and, therefore, the kneading movement can be certainly made by the main massage rollers  137 . 
     On the other hand, when the eccentric rotation of the eccentric cum portion  157  of the eccentric cum body  155  moves downwardly from the top dead center while the second drive shaft  124  is rotated to allow the main massage rollers  137  to make the kneading movement, the second drive shaft  124  may be radically rotated together with the eccentric cum body  155  due to the user&#39;s load applied to the main massage rollers  137 . That is, the parts of the arms  127  where the main massage rollers  137  are provided may radically fall with the proximal end part serving as a fulcrum. 
     However, the friction member  207  is provided on the side surface of the second helical gear  198  of the gear train, which transmits the rotation of the reversible motor  182  to the second drive shaft  124 . Thus, if the eccentric cum body  155  is to radically rotate together with the second drive shaft  124 , the second helical gear  198  slightly moves along the third support shaft  199 , and the friction member  207  provided on the side surface of the second helical gear  198  abuts on the outer wall surface of the recess portion  196  to generate the friction force. 
     As a result, the friction force reduces the speed of rotation of the second drive shaft  124  and the second drive shaft  124  is thereby restricted from rotating radically. That is, it is possible to prevent the main massage rollers  137  from falling radically during the kneading movement and, therefore, preferable massage can be provided. 
     On the other hand, the arm cover  135  is bonded to the arm housing  132  of the arm  127  and the slider  143  is provided at the holding portion  142  formed between the bonding surfaces thereof. 
     For this reason, the sliders  143  for allowing the main massage rollers  137  to make the kneading movement can be provided in the arms  127  so as to certainly slide with a simple structure. 
     The main massage rollers  137  are provided to be freely rotatable on the support shafts  136  formed integrally with the arm housings  132  and are held by fitting the attachment screws  141  in the arm covers  135  through the support shafts  136 . 
     For this reason, the support shafts  136  are constituted integrally with the arm housings  132 . Therefore, the structure can be simplified and the assembling operation can be facilitated as compared to a case where they are provided separately from one another, and the main massage rollers  137  can be certainly providing without being loose. 
     The power box  122 , which contains the reversible motor  182 , is composed of the metal main body portion  122   a  formed of aluminum die-casting and the lid portion  122   b  formed of synthetic resin. For this reason, when the reversible motor  182  is operated and heat is thereby generated, the heat is radiated to the outside through the main body portion  182 . Therefore, it is possible to prevent the heat from being so accumulated inside the power box  122  and the temperature of the reversible motor  182  from rising excessively. 
     On the other hand, the lid portion  122   b  of the power box  122  is formed of synthetic resin. Thus, the overall power box  122  can be made more right-weight as compared with a case where the overall power box  122  is formed of metal. Further, the lid portion  122   b  is positioned on the outer side in the lateral direction of the holding body  21 . For this reason, even if the holding body  21  is in sliding contact with the exterior cover  20  and the like at the time of reciprocates along the guide rails  4 , it is possible to prevent the exterior cover  20  and the like from being damaged at an early time. 
     In the above-described embodiment, the mattress type massage apparatus has been explained. The massage apparatus of the present invention may be designed to be in a chair type. In addition, the center rollers  171  and the side rollers  172  may be formed by foam molding using urethane resin, similarly to the main massage rollers  137  and the auxiliary massage rollers  173 . 
     FIG. 33 is a plan view showing the massage apparatus according to a second embodiment of the present invention. In this massage apparatus, an attachment shaft  232  at which a plurality of massage rollers  231  are provided to be freely rotatable at a determined distance from the holding body  21  is provided on a pair of guide rails  4  provided on the base  1 , as well as the holding body  21 . Support members  233  are provided at both ends of the attachment shaft  232 . The support members  233  are coupled to the belts  15  that are driven to run along the guide rails  4 . 
     The projecting part of the power box  122  provided in the holding body  21 , i.e. the part in which the reversible motor  182  is provided, faces in a direction opposite to that of the above embodiment, i.e. a direction of the drive device  10 . In this case, the first drive shaft  123  is provided on the side portion at an opposite side to the drive device  10  of the holding body  21 , though not shown in detail. 
     In this structure, the massage rollers  231  run along the guide rails  4  together with the holding body  21 . Therefore, the massage rollers  231  can also massage the user&#39;s body. That is, the massage apparatus having a high massage effect can be provided. 
     The same portions of the second embodiment as those of the first embodiment are denoted by the same reference numerals and their explanation has been omitted. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.