Patent Publication Number: US-10772786-B2

Title: Load-relieving apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese patent application No. 2017-181357, filed on Sep. 21, 2017, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     The present disclosure relates to a load-relieving apparatus. 
     Support systems for supporting rehabilitation of patients who suffer from lower-limb paralysis caused by strokes or the like have been developed. Such support systems can enable, for example, patients with paralyzed lower limbs to do walking trainings. In a walking training, a walking assisting apparatus is attached to a leg of a trainee, i.e., a patient with a paralyzed lower limb. The walking assisting apparatus is attached to the paralyzed leg and assists the trainee in performing knee bending/extending motions. The trainee wearing the walking assisting apparatus walks on a treadmill provided in the support apparatus. It should be noted that the walking assisting apparatus or the leg to which the walking assisting apparatus is attached is pulled in an upper-front direction and an upper-rear direction by a load-relieving apparatus. The load-relieving apparatus supports the weight of the walking assisting apparatus and assists the trainee in moving his/her leg by paying out or pulling in wire cables from positions located above and in front of the trainee, and above and behind the trainee. 
     As an example of a technique related to the above-described load-relieving apparatus, a lifting/lowering apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2004-141517 includes a wire cable with locking means for suspending a suspended object attached to one end thereof, a winding drum for winding up this wire cable, and winding momentum-giving means for giving rotational momentum to the winding drum in a winding direction. Further, in this lifting/lowering apparatus, an insertion nut and a stopper through which the wire cable is inserted are attached to a base plate covering the winding drum, so that the locking means provided at the free end of the wire cable does not come into contact with the winding drum. 
     SUMMARY 
     The present inventors have found the following problem. In the above-described load-relieving apparatus, there is a part where the wire cable is wound is directly exposed, which is undesirable in view of safety. Therefore, the above-described load-relieving apparatus is equipped with a cover that eliminates the exposure of the part where the wire cable is wound. Further, in the above-described load-relieving apparatus, a through hole through which the wire cable is inserted is formed in the cover in order to wind or pull the wire cable therethrough. It is desirable that this through hole be small in view of safety. It should be noted that a load-relieving apparatus used in a walking assisting apparatus may assist a trainee in moving his/her leg in a left/right direction of his/her body in addition to the motion in the front/rear direction (e.g., a swinging motion of the leg in the front/rear direction). In such a case, the wire cable of the load-relieving apparatus may be pulled in a direction perpendicular to the motion in the front/rear direction of the body (e.g., the leg swinging motion) in addition to the direction parallel to the motion in the front/rear direction of the body (e.g., the leg swinging motion). However, when the related technique disclosed in Japanese Unexamined Patent Application Publication No. 2004-141517 is used for the above-described walking training apparatus, the wire cable is repeatedly paid out and pulled in in a state where the wire cable is in contact with the cover of the winding drum. When the wire cable is repeatedly paid out and pulled in in the state where the wire cable is in contact with the cover, the wire cable could be worn out. When the wire cable is worn out, the cost for maintaining the apparatus could increase. 
     The present disclosure has been made to solve the above-described problem and an object thereof is to provide a load-relieving apparatus capable of suppressing wear of a wire cable. 
     A first exemplary aspect is a load-relieving apparatus including: 
     a wire cable with a free end and a fixed end opposite to the free end, a locking part being attached to the free end; 
     a winding part configured to wind the wire cable from a fixed-end side thereof; 
     a pulley interposed between the winding part and the locking part, and configured to stretch the wire cable therebetween; and 
     a cover with a through hole formed therein through which the wire cable is inserted, the cover being interposed between the locking part and the pulley, and formed so as to cover at least a part of the pulley, in which 
     the cover (the through hole) is configured so that a relative position of the cover (the through hole) with respect to a rotation axis of the pulley changes (is variable). 
     By the above-described configuration, the cover can be moved so that its relative position changes with respect to the pulley (the rotation axis of the pulley). Therefore, the cover can follow the movement of the wire cable. In other words, the through hole of the cover can follow the movement of the wire cable. 
     According to the present disclosure, it is possible to provide a load-relieving apparatus capable of suppressing wear of a wire cable. 
     The above and other objects, features and advantages of the present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a schematic configuration of a walking training system according to a first embodiment; 
         FIG. 2  is a top view of a load-relieving apparatus according to the first embodiment; 
         FIG. 3  is a side view of the load-relieving apparatus according to the first embodiment; 
         FIG. 4  is a front view of the load-relieving apparatus according to the first embodiment; 
         FIG. 5  is a cross section of the load-relieving apparatus according to the first embodiment; 
         FIG. 6  is a top view of the walking training system according to the first embodiment; 
         FIG. 7  is a side view of the walking training system according to the first embodiment; 
         FIG. 8  is a top view of the walking training system according to the first embodiment; 
         FIG. 9  is a schematic diagram for explaining a movement of a wire cable of the load-relieving apparatus in a pitch direction; 
         FIG. 10  is a schematic diagram for explaining a movement of the wire cable of the load-relieving apparatus in the pitch direction; 
         FIG. 11  is a schematic diagram for explaining a movement of the wire cable of the load-relieving apparatus in a roll direction; and 
         FIG. 12  is a top view of a load-relieving apparatus according to a second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     A first embodiment according to the present disclosure is described hereinafter with reference to the drawings. 
       FIG. 1  is a perspective view showing a schematic configuration of a walking training system  1  according to the first embodiment. The walking training system  1  according to this embodiment is, for example, a system for enabling a trainee U such as a patient having hemiplegia caused by a stroke to do a walking training. As shown in  FIG. 1 , the walking training system  1  includes a walking assisting apparatus  2  attached to a leg of the trainee U and a training apparatus  3  by which the trainee U does a walking training. 
     The walking assisting apparatus  2  is attached to, for example, a diseased leg of a trainee U who does a walking training (in  FIG. 1 , a right leg of the trainee U) and assists the trainee U in his/her walking. The walking assisting apparatus  2  is an apparatus that is attached to a paralyzed leg and assists the patient in performing knee bending/extending motions. The walking assisting apparatus  2  includes an upper thigh frame, a lower thigh frame connected to the upper thigh frame through a knee joint part, and a sole frame connected to the lower thigh frame through an ankle joint part. Further, the walking assisting apparatus  2  includes a drive unit and rotationally drives the knee joint part or the ankle joint part. 
     The training apparatus  3  includes a treadmill  31 , a frame main body  32 , a first load-relieving apparatus  33 , a second load-relieving apparatus  34 , first and second wire-cable length detection units  41  and  42 , which serve as detection means, and a control apparatus  35 . 
     The treadmill  31  includes a ring-shaped rotatable belt conveyor  311  on which the trainee U walks. The trainee U gets on the belt conveyor  311  and walks thereon according to the movement of the belt conveyor  311 . 
     The frame main body  32  includes two pairs of pillar frames  321  vertically disposed on the treadmill  31 , a pair of lengthwise frames  322  extending in the front/rear direction and connected to respective pillar frames  321 , and front and rear crosswise frames  323  and  324  extending in the left/right direction and connected to each of the lengthwise frames  322 . Note that the structure of the frame main body  32  is not limited to this example. The frame main body  32  may have an arbitrary frame structure as long as it can properly fix the first and second load-relieving apparatus  33  and  34  thereto. 
     The first load-relieving apparatus  33  supports the weight of the walking assisting apparatus and assists the trainee in moving his/her leg by paying out or pulling in the wire from a position located above and in front of the trainee. The first load-relieving apparatus  33  is disposed in a position located above the trainee U and in front of the trainee U in the traveling direction. For example, the first load-relieving apparatus  33  is disposed in the front crosswise frame  323 , which is located above the trainee U and in front of the trainee U in the traveling direction. The first load-relieving apparatus  33  pulls the leg of the trainee U to which the walking assisting apparatus  2  is attached upward and forward through a first wire cable  36 . The first load-relieving apparatus  33  is connected to the control apparatus  35  (which will be described later) through a wiring line or the like. Details of the first load-relieving apparatus  33  will be described later. 
     One end of the first wire cable  36  hangs down from the first load-relieving apparatus  33  and is attached directly or indirectly to the leg of the trainee U. For example, one end of the first wire cable  36  is attached to the walking assisting apparatus  2  attached to the leg of the trainee U. The other end of the first wire cable  36  is supported in the first load-relieving apparatus  33  and wound around a winding mechanism. 
     The second load-relieving apparatus  34  supports the weight of the walking assisting apparatus and assists the trainee in moving his/her leg by paying out or pulling in the wire cable from a position located above and behind the trainee. The second load-relieving apparatus  34  is disposed in a position located above the trainee U and behind the trainee U in the traveling direction. For example, the second load-relieving apparatus  34  is disposed in the rear crosswise frame  324 , which is located above the trainee U and behind the trainee U in the traveling direction. The second load-relieving apparatus  34  pulls the leg of the trainee U to which the walking assisting apparatus  2  is attached upward and rearward through a second wire cable  37 . The second load-relieving apparatus  34  is composed of, for example, a winding mechanism such as a drum that winds and rewinds the second wire cable  37 , a motor that drives the winding mechanism, and so on. The second load-relieving apparatus  34  is connected to the control apparatus  35  (which will be described later) through a wiring line or the like. The second load-relieving apparatus  34  has a configuration similar to that of the first load-relieving apparatus. Details of the second load-relieving apparatus  34  will be described later. 
     One end of the second wire cable  37  hangs down from the second load-relieving apparatus  34  and is attached directly or indirectly to the leg of the trainee U. For example, one end of the second wire cable  37  is attached to the walking assisting apparatus  2  attached to the leg of the trainee U. The other end of the second wire cable  37  is supported in the second load-relieving apparatus  34  and wound around a winding mechanism. 
     The detection means detects paid-out lengths of the first and second wire cables  36  and  37 . For example, the detecting means includes a first wire-cable length detection unit  41  and a second wire-cable length detection unit  42 . The first wire-cable length detection unit  41  is, for example, a sensor such as a rotary encoder that is provided on a winding shaft of the winding mechanism of the first load-relieving apparatus  33  and detects a rotation angle of the winding shaft. A length (a winding amount) by which the winding mechanism has wound the first wire cable  36  is calculated from a detection signal of the first wire-cable length detection unit  41 . Further, the paid-out length of the first wire cable  36  is detected (i.e., calculated) by subtracting this winding amount from the already-known total length of the first wire cable  36 . The first wire-cable length detection unit  41  is connected to the control apparatus  35  (which will be described later) through a wiring line or the like. 
     The second wire-cable length detection unit  42  is, for example, a sensor such as a rotary encoder that is provided on a winding shaft of the winding mechanism of the second load-relieving apparatus  34  and detects a rotation angle of the winding shaft. A length (a winding amount) by which the winding mechanism has wound the second wire cable  37  is calculated from a detection signal of the second wire-cable length detection unit  42 . Further, the paid-out length of the second wire cable  37  is detected (i.e., calculated) by subtracting this winding amount from the already-known total length of the second wire cable  37 . The second wire-cable length detection unit  42  is connected to the control apparatus  35  (which will be described later) through a wiring line or the like. Note that the above-described detection means is not limited to those composed of the first and second wire-cable length detection units  41  and  42 . Any means capable of detecting (or measuring) the paid-out lengths of the first and second wire cables  36  and  37  may be used. For example, image pick-up means such as a camera that detects external-appearance information (a position) of a wire cable may be used. 
     The control apparatus  35  controls pulling forces by which the first and second load-relieving apparatuses  33  and  34  respectively pull the wire cables, and controls the operation performed by the walking assisting apparatus  2 . For example, the control apparatus  35  detects that the leg of the trainee U to which the walking assisting apparatus  2  is attached is lifted from the ground (i.e., from the belt conveyer) or set down on the ground. That is, the control apparatus  35  can detect a timing at which the leg of the trainee to which the walking assisting apparatus  2  is attached changes from a leg-standing state to a leg-idling state, and a timing at which the leg changes from the leg-idling state to the leg-standing state based on sensor data supplied from a ground-contact sensor. Upon detecting the timing at which the leg changes from the leg-standing state to the leg-idling state, the control apparatus  35  starts to control a motor unit included in the walking assisting apparatus at that timing. 
     For example, the control apparatus  35  is composed of hardware mainly using a microcomputer including a CPU (Central Processing Unit) that performs arithmetic processing, control processing, and so on, a ROM (Read Only Memory) that stores an arithmetic program, a control program, etc. to be executed by the CPU, a RAM (Random Access Memory) that stores various types of data, and an interface unit (I/F) that externally receives and outputs signals. The CPU, the ROM, the RAM, and the interface unit are connected with each other through a data bus or the like. 
     Next, details of the first and second load-relieving apparatuses  33  and  34  are described with reference to  FIGS. 2 to 4 . The first and second load-relieving apparatuses  33  and  34  have configurations similar to each other, except that they are engaged with (i.e., fixed to) frames different from each other. In the following description, only the first load-relieving apparatus  33  is described. However, the same matters also apply to the second load-relieving apparatus  34 . 
       FIG. 2  is a top view of a load-relieving apparatus according to the first embodiment.  FIG. 3  is a side view of the first load-relieving apparatus according to the first embodiment.  FIG. 4  is a front view of the load-relieving apparatus according to the first embodiment.  FIG. 2  shows a right-handed xyz-coordinate system in addition to the top view of the load-relieving apparatus  33 . That is, a vertical direction in the drawing indicates a z-axis direction in the xyz-coordinate system, and the front side is the plus side in the z-axis direction. A horizontal direction in the drawing indicates an x-axis direction in the xyz-coordinate system, and the right side is the plus side in the x-axis direction. A vertical direction in the drawing indicates a y-axis direction in the xyz-coordinate system, and the upper side is the plus side in the y-axis direction. Note that right-handed xyz-coordinate systems shown in  FIGS. 2 to 11  are shown only for the sake of convenience for explaining positional relations among components. The z-axis direction in  FIG. 2  coincides with the z-axis directions in  FIGS. 3 to 11 . 
     Further, in the following description, a swinging direction of a wire cable or the like, or a rotation direction of an object is defined as follows. A direction of a rotation around the x-axis indicated by an arrow P is defined as a pitch direction. A direction of a rotation around the y-axis indicated by an arrow R is defined as a roll direction. A direction of a rotation about the z-axis indicated by an arrow Y is defined as a yaw direction. 
     The first load-relieving apparatus  33  mainly includes a first wire cable  36 , a wire locking member  361 , a support plate  331 , an apparatus fixing part  332 , a drive unit  333 , a winding part  334 , a pulley  335 , and a cover  336 . 
     The first wire cable  36  has a free end to which the wire locking member  361  is attached and a fixed end opposite to the free end. The free end of the first wire cable  36  hangs down from the first load-relieving apparatus  33  and the wire locking member  361  is attached directly or indirectly to a leg of a trainee U. The fixed end of the first wire cable  36  is fixed to the winding part  334 . Further, the first wire cable  36  is wound around the winding part  334 . 
     The wire locking member  361  is a locking component attached to the free end of the first wire cable  36 . The wire locking member  361  includes a locking piece  362  such as a hole or a hook for locking the wire locking member  361  in the walking assisting apparatus  2 . 
     The support plate  331  is a support component that supports each structure of the load-relieving apparatus. More specifically, the support plate  331  supports the drive unit  333 , the winding part  334 , and the pulley  335 . 
     The support plate  331  includes an apparatus fixing part  332 . The apparatus fixing part  332  is engaged with the front crosswise frame  323  and is fixed by arbitrary fixing means (not shown) so that the support plate  331  does not move relative to the front crosswise frame  323 . 
     The support plate  331  includes a cover stopper  331 S. The cover stopper  331 S is a component for restricting the rotation of the cover  336 . The cover stopper  331 S is provided to stop the movement of the cover  336  in the rotation direction by coming into contact with a corresponding contact part  336 S of the cover  336 , and thereby prevent the cover  336  from making one rotation or more. 
     The drive unit  333  is connected to the winding part  334  and rotates the winding part  334 . The drive unit  333  is formed by driving means including a motor. The driving unit  333  is controlled by the control unit  35  and rotates the winding part  334  in order to pay out or pull in the first wire cable  36  as described above. Note that instead of being a motor, the driving unit  333  may be momentum-giving means using a tension coil spring, a spiral spring, or the like. 
     The winding part  334  is a drum-shaped component that winds the fixed-end side of the first wire cable  36 . The winding part  334  is connected to the drive unit  333 , and is configured so that the drum-shaped component is rotated by the drive unit  333 . The winding amount of the first wire cable  36  wound by the winding part  334  or the length of the cable that has been paid out by the winding part  334  is controlled by the above-described first wire-cable length detection unit  41  (not shown), the drive unit  333 , and the control apparatus  35 . 
     The pulley  335  is interposed between the winding part  334  and the wire locking member  361 , and stretches the first wire cable  36 . By being interposed between the winding part  334  and the wire locking member  361 , the pulley  335  guides the first wire cable  36  while preventing the first wire cable  36  from being excessively bent. 
     The cover  336  is a hollow spindle-shaped component that is formed so as to cover at least a part of the pulley  335  in order to prevent the pulley from being directly exposed. The cover  336  is rotatably locked on the same axis as an axis CR which is the rotation center of the pulley  335  (a direction indicated by an arrow P in  FIG. 3 ). The cover  336  includes a communication hole  337 , a stopper  338 , and a contact part  336 S. The first wire cable  36  paid out from the winding part  334  is inserted through the communication hole  337 . Further, the first wire cable  36  paid out from the pulley is inserted through the stopper  338 . 
     That is, the first wire cable  36  is paid out from the winding part  334 , passes through the communication hole  337 , and is stretched through the pulley  335 . Then, the first wire cable  36  paid out from the pulley  335  passes through the stopper  338  and is connected to the wire locking member  361 . 
     The stopper  338  is formed so that the wire locking member  361  does not come into contact with the pulley  335  when the first wire cable  36  is wound around the winding part  334  and the wire locking member  361  is thereby pulled into the stopper  338 .  FIG. 4  shows details of the stopper  338 . The stopper  338  has a through hole  338 H through which the first wire cable  36  inserted in such a manner that it can pass through the through hole  338 H without restraint. The through hole  338 H extends in a direction parallel to the axis CR. In other words, the through hole  338 H has a slit shape extending parallel to an axial direction of the rotation axis of the pulley  335 . Specifically, the through hole  338 H is formed so that its width  338 A in the axial direction of the axis CR becomes longer than its width  338 B in a tangential direction of the axis CR. Further, in order to prevent the wire locking member  361  from passing through the through hole  338 H, the through hole  338 H is formed so that its width  338 A in the axial direction of the axis CR becomes narrower than the width of the wire locking member  361 . 
     The contact part  336 S is a component for restricting the rotation of the cover  336 . The contact part  336 S is formed in a place in which it comes into contact with the cover stopper  331 S. Therefore, when the first wire cable  36  is wound around the winding part  334  and the wire locking member  361  is pulled into the fixed-end side, the wire locking member  361  comes into contact with the stopper  338  and hence the stopper  338  no longer continues to get any closer to the pulley  335 . When the winding part  334  further winds the first wire cable  36 , the cover  336  rotates to a position where the contact part  336 S comes into contact with the cover stopper  331 S. When the cover  336  rotates to the position where the contact part  336 S is in contact with the cover stopper  331 S, the cover  336  stops rotating. Therefore, the wire locking member  361  is no longer pulled into the fixed-end side. Note that the cover stopper  331 S and the contact part  336 S may have forms different from those shown in  FIGS. 2 to 4  as long as they restrict the rotation of the cover  336 . Further, the cover stopper  331 S and the contact part  336 S may restrict the rotation of the cover  336  in a direction opposite to the direction in which the wire locking member  361  is pulled in. 
     Next, a structure of a part where the pulley  335  and the cover  336  are disposed is described in detail with reference to  FIG. 5 .  FIG. 5  is a cross section of the load-relieving apparatus according to the first embodiment.  FIG. 5  shows a cross section IV in  FIG. 2 . In the first load-relieving apparatus  33 , a shaft  339  is provided in a protruding state in the support plate  331 . A brim for dislodging prevention is provided at a tip of the shaft  339 . As viewed from the support plate  331  side, a first collar  340 , a pulley  335 , a second collar  341 , and a third collar  342  are put on the shaft  339  in this order. Further, a cover  336  is pivotally supported on the outer circumference of the third collar  342 . Further, the cover  336  is locked in the thrust direction of the shaft  339  by brims of the second and third collars  341  and  342  to such a degree that the cover  336  does not rattle in the thrust direction. By the above-described structure, the pulley  335  and the cover  336  are rotatably fixed in the thrust direction of the shaft  339  while being prevented from rattling. 
     Although both the pulley  335  and the cover  336  are pivotally supported on the shaft  339 , the means for supporting the cover  336  is not limited to this example. For example, the cover  336  may be supported on a support component different from the shaft  339 . Further, the rotation center of the pulley  335  and the rotation center of the cover  336  may be different from each other. In such a case, it is preferable that the rotation axes of the pulley  335  and the cover  336  be roughly parallel to each other. That is, the through hole  338 H of the cover  336  is formed so that the cover  336  can rotate around an axis parallel to the rotation axis of the pulley  335 . In this way, the through hole  338 H of the cover  336  can follow the movement of the pulley  335  in the pitch direction. 
     Further, the cover  336  may have no rotation axis and may be configured to perform a reciprocating motion. In such a case, the through hole  338 H of the cover  336  is formed so as to be able to reciprocate in a direction perpendicular to the rotation axis of the pulley  335 . In this way, the through hole  338 H of the cover  336  can follow the movement of the pulley  335  in the pitch direction. 
     Further, the shape of the cover  336  is not limited to the hollow spindle shape as described above. That is, the cover  336  may be, for example, a hollow cubic shape, a curved planar shape, or a combination of a plurality of flat surfaces and curved surfaces as long as it has the above-described function. 
     Further, the form of the cover  336  is not limited to the above-described structure. That is, the only requirement for the cover  336  is that a relative position of a part  336 A of the cover  336  including the through hole  338 H should be variable (movable) with respect to a part  336 B of the other part of the cover  336 , so that the cover  336  should have a function of making a relative position of the through hole  338 H variable (movable) with respect to the rotation axis of the pulley  335 . For example, the cover  336  may be formed as a flat surface (spherical surface) sliding mechanism composed of a pair of a part  336 A having a curved-surface (or flat-surface) shape and a part  336 B having a curved-surface (or flat-surface) shape corresponding to the curved-surface (or flat-surface) shape of the part  336 A. Alternatively, for example, the cover  336  may be formed as a movable mechanism composed of a pair of a part  336 A formed of a rigid component made of a metal, resin, etc. and a part  336 B formed of a soft component made of soft rubber etc. 
     Next, a use state of the first load-relieving apparatus  33  is described with reference to  FIGS. 6 to 8 . 
       FIG. 6  is a top view of a walking training system according to the first embodiment.  FIG. 6  shows a state in a walking training performed by a trainee U. The walking training system  1  is configured so that paid-out lengths of the first and second wire cables  36  and  37  change according to the walking performed by the trainee U. A component in the z-axis direction of a tensile force FF 1  applied by the first load-relieving apparatus  33  and a component in the z-axis direction of a tensile force FR 1  applied by the second load-relieving apparatus  34  support the weight of the walking assisting apparatus  2 . A component in the y-axis direction of the tensile force FF 1  applied by the first load-relieving apparatus  33  assists a forward swinging motion in the traveling direction of the leg of the trainee U to which the walking assisting apparatus  2  is attached. A component in the y-axis direction of the tensile force FR 1  applied by the second load-relieving apparatus  34  assists a rearward swinging motion in the traveling direction of the leg of the trainee U to which the walking assisting apparatus  2  is attached. In this way, it is possible to reduce the walking load of the trainee U in the walking training. 
       FIG. 7  is a side view of the walking training system according to the first embodiment.  FIG. 7  is a side view showing the state shown in  FIG. 6 . In the state in the walking training shown in  FIGS. 6 and 7 , the trainee U walks by swinging his/her leg in the y-axis direction. The first load-relieving apparatus  33  is fixed to a position located above and in front of the leg in which the first wire cable  36  is locked. Therefore, the first wire cable  36  pulls the leg in the y-axis positive direction and the z-axis positive direction by a tensile force FF 1 . Meanwhile, the second load-relieving apparatus  34  is fixed to a position located above and behind the leg in which the second wire cable  37  is locked. Therefore, the second wire cable  37  pulls the leg in the y-axis negative direction and the z-axis positive direction by a tensile force FR 1 . 
     The trainee U swings the leg in front of and behind the trainee in the walking training. When doing so, the leg also moves in the z-axis direction in addition to the y-axis direction. Therefore, each of the first and second wire cables  36  and  37 , which assist the leg, swings in the pitch direction. In this process, the cover  336  of the first load-relieving apparatus  33  can follow the movement of the first wire cable  36  in the pitch direction. Similarly, the cover  336  of the second load-relieving apparatus  34  can follow the movement of the second wire cable  37  in the pitch direction. 
     Next, another state in the walking training is described with reference to  FIG. 8 .  FIG. 8  is a top view of the walking training system according to the first embodiment.  FIG. 8  shows a state in the walking training performed by the trainee U different from the state shown in  FIG. 6 . In the example shown in  FIG. 8 , the forward swinging motion of the leg performed by the trainee U involves an outward rotation. That is, the leg of the trainee U is swung in a direction indicated by an arrow FU 2 . The arrow FU 2  indicates that the swinging motion includes a component in the x-axis direction in addition to components in the y-axis positive direction and in the z-axis direction. Walking involving an excessive outward rotation is not desirable as a walking motion. Therefore, the walking training system  1  assists the walking while pulling the leg in the x-axis negative direction through the first wire cable  36  in order to cancel out the force in the x-axis positive direction indicated by the arrow FU 2 . In such a walking training state, the first load-relieving apparatus  33  is fixed to a position located above and in front of, and to the left of the trainee U. That is, the first load-relieving apparatus  33  is fixed to a place that is shifted in the x-axis negative direction from the place shown in  FIG. 6 . In such a case, the first wire cable  36  has a tensile force FF 2  having components in the y-axis positive direction, the z-axis positive direction, and the x-axis negative direction. Further, the first wire cable  36  also swings widely in the roll direction in addition to the pitch direction shown in  FIG. 7 . 
     As shown in  FIG. 4 , the cover  336  of the first load-relieving apparatus  33  has the through hole  338 H having the width  338 A in the x-axis direction. Therefore, the cover  336  of the first load-relieving apparatus  33  can allow a movement of the first wire cable  36  in the roll direction within a range corresponding to the width  338 A in the x-axis direction of the through hole  338 H. 
     Next, a movement of the cover  336  in the pitch direction is described with reference to  FIGS. 9 and 10 .  FIG. 9  is a schematic diagram for explaining a movement of the wire cable of the load-relieving apparatus in the pitch direction. The first wire cable  36  is paid out from the stopper  338  of the cover  336 . In  FIG. 9 , the first wire cable  36  extends in a position inclined from the z-axis direction by an angle P 1 . Meanwhile, in  FIG. 10 , the first wire cable  36  extends in a position inclined from the z-axis direction by an angle P 2 . In the first load-relieving apparatus  33 , since the stopper  338  can move in the rotation direction of the pulley  335  as described above, the stopper  338  can follow the movement of the first wire cable  36 . 
     Note that since the stopper  338  is rotatably fixed, the stopper  338  could come into contact with the first wire cable  36 . A contact point X shown in  FIG. 10  indicates a state in which the stopper  338  and the first wire cable  36  are in contact with each other. Even in such a state, the first wire cable  36  is not bent by the stopper  338  and hence the first wire cable  36  is not worn at the contact point X. Further, in consideration of the contact between the stopper  338  and the first wire cable  36 , the stopper  338  is processed (e.g., machined) so that no edge is present around the through hole  338 H. 
     Next, a movement of the first wire cable  36  in the roll direction is described with reference to  FIG. 11 .  FIG. 11  is a front view for explaining a movement of the wire of the load-relieving apparatus in the roll direction. The first wire cable  36  swings around the axis CR parallel to the y-axis in the roll direction with the place where the cable is paid out from the pulley  335  being the center of the swing. 
     The first wire cable  36  paid out from the through hole  338 H of the cover  336  can be used without being worn in a range in which the first wire cable  36  does not come into contact with the width  338 A in the x-axis direction of the through hole  338 H. That is, even if the motion of the leg performed by the trainee U involves an outward rotation as shown in  FIG. 8 , the first wire cable  36  does not come into contact with the stopper  338 , for example, within a range of an angle RI. 
     In the first embodiment, by the above-described configuration, it is possible to provide a load-relieving apparatus capable of suppressing wear of a wire cable. 
     Second Embodiment 
     Next, a second embodiment is described with reference to  FIG. 12 .  FIG. 12  is a top view of a load-relieving apparatus according to the second embodiment. The load-relieving apparatus  43  according to the second embodiment is substantially the same as the load-relieving apparatus according to the first embodiment, except for the support means disposed between the support plate  331  and the front crosswise frame  323 . 
     The load-relieving apparatus  43  includes a rotation support part  432  between the support plate  331  and the apparatus fixing part  332 . The rotation support part  432  is a support component that supports the support plate  331  in such a manner that the support plate  331  can rotate around an axis CY parallel to the z-axis in a direction indicated by an arrow Y. The rotation support part  432  is, for example, a fixing component including a rolling bearing. 
     In the second embodiment, by the above-described configuration, when a direction in which the trainee U walks (i.e., a y-axis positive direction) is defined as a forward in the walking training system  1 , the load-relieving apparatus  43  can provide flexibility around the axis CY in a yaw direction (a direction indicated by an arrow Y). That is, in the load-relieving apparatus  43  according to the second embodiment, the cover (or the through hole) can follow the wire cable in the pitch direction, the roll direction, and the yaw direction. Therefore, the second embodiment can provide a load-relieving apparatus capable of suppressing wear of a wire cable. 
     Note that the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present disclosure. 
     From the disclosure thus described, it will be obvious that the embodiments of the disclosure may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.