Abstract:
An auxiliary device for muscle strength training is provided, which includes: a base; a sliding member slidingly coupled to the base; and a connecting-rod mechanism connected to the base and the sliding member in such a way that a positional shift of the sliding member allows the connecting-rod mechanism to rotate relative to the base and change its state. As such, the auxiliary device has first and second configurations to assist patients who are incapable of controlling their muscles by themselves to effectively train specific muscle groups. Further, elastic members are connected to the base and the connecting-rod mechanism and provide elastic potential energies so as to keep the auxiliary device in static equilibrium. The auxiliary device has a simple structure and is easily manufactured at a low cost and applicable for patients with muscle strength lower than grade 3.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to auxiliary devices for muscle strength training, and more particularly, to an auxiliary device for improving muscle strength training effect. 
         [0003]    2. Description of Related Art 
         [0004]    Rehabilitation therapy for patients with limb paralysis, for example, leg paralysis, is an important issue in the field of physical therapy. Limb paralysis may be caused by a cerebral vascular accident (CVA), a complete or incomplete spinal cord injury, a spinal cord vascular disease, a stroke and so on. After assessing patients&#39; individual conditions, physical therapists develop specialized training plans for the patients. Physical training includes such as muscle strength training, standing balance training and weight shift training. Therein, leg muscle strength training is especially important since leg muscle strength is important in supporting the upper body of a patient. 
         [0005]    In particular, physical therapists assess patients&#39; muscle strength conditions and provide different levels of muscle strength training. In addition, different auxiliary devices are used according to different levels of muscle strength training. A manual muscle test (MMT) is generally performed to determine the grade of muscle strength. Muscle strength is graded from 0 to 5. At grade 0, no muscle contraction can be seen. At grade 1, a muscle contraction can be seen. At grade 2, a training movement can be achieved only with gravity eliminated. At grade 3, a training movement can be achieved against gravity. At grades 4 and 5, a complete training movement can be achieved against moderate or full resistance. 
         [0006]    The auxiliary devices can be classified into active type and passive type. The passive-type auxiliary devices enable passive muscle strength training for patients, and the active-type auxiliary devices allow patients to perform active muscle strength training. Generally, the active-type auxiliary devices are preferred due to a better rehabilitation effect. Further, since the passive-type auxiliary devices are usually driven by electronic devices such as motors, the passive-type auxiliary devices have a high manufacturing cost and are large in size. Therefore, compared with the passive-type auxiliary devices, the active-type auxiliary devices are smaller, lighter and cheaper. 
         [0007]    However, the conventional active-type auxiliary devices only provide resistance and are only applicable for patients with muscle strength above grade 3. For patients with muscle strength below grade 3, the passive-type auxiliary devices are required. Further, in order to adjust the resistance value of a conventional active-type auxiliary device, elastic elements of the auxiliary device need to be changed or relative positions of internal components of the auxiliary device needs to be adjusted, thus resulting in considerable inconvenient in use. Furthermore, since the conventional active-type auxiliary devices cannot assist patients who are incapable of controlling their muscles by themselves (i.e., with muscle strength below grade 3) to perform muscle strength training, specific muscle groups of the patients cannot be effectively trained. 
         [0008]    Therefore, there is a need to provide an auxiliary device for muscle strength training so as to overcome the above-described drawbacks. 
       SUMMARY OF THE INVENTION 
       [0009]    In view of the above-described drawbacks, the present invention provides an auxiliary device for muscle strength training, which comprises: a base having a sliding rail; a first rod having a sliding slot, a first connecting member pivotally connected to the base and a second connecting member opposite to the first connecting member; a sliding member having a first end slidingly coupled to the sliding rail of the base and a second end opposite to the first end and slidingly received in the sliding slot of the first rod; a second rod having a third connecting member and a fourth connecting member, wherein the third connecting member is pivotally connected to the second connecting member of the first rod; a third rod having a fifth connecting member and a sixth connecting member, wherein the fifth connecting member is pivotally connected to the fourth connecting member of the second rod; a fourth rod having a seventh connecting member and an eighth connecting member, wherein the seventh connecting member is pivotally connected to the sixth connecting member of the third rod; and a fifth rod having a ninth connecting member and a tenth connecting member, wherein the ninth connecting member is pivotally connected between the seventh connecting member and the eighth connecting member of the fourth rod and the tenth connecting member is pivotally connected to the sliding member; wherein when the auxiliary device is in a first configuration, the second end of the sliding member is coaxial with the first connecting member of the first rod so as to allow the first rod to rotate relative to the base. Further, when the auxiliary device is in a second configuration, the second rod rotates relative to the first rod so as to cause the second end of the sliding member to slide in the sliding slot of the first rod and prevent the first rod from moving relative to the base. 
         [0010]    In an embodiment, the auxiliary device further comprises a first elastic member connected between the base and the first rod. When the auxiliary device is in the first configuration, the first elastic member constantly provides an elastic potential energy to keep the auxiliary device in static equilibrium. 
         [0011]    Therefore, the auxiliary device of the present invention is simple in construction. To adjust the resistance value of the auxiliary device, the present invention does not need to change elastic members or perform complicated operations to adjust relative positions of internal components of the auxiliary device as in the prior art, thereby improving the convenience in use of the active-type auxiliary device. 
         [0012]    Further, the auxiliary device of the present invention has one degree of freedom due to restriction of relative movements of the rods in the connecting-rod mechanism. Furthermore, an elastic member connected to the connecting-rod mechanism provides an elastic potential energy to support a total gravitational potential energy of the auxiliary device and a human body connected to the auxiliary device so as to reach static equilibrium. As such, the auxiliary device of the present invention is applicable for patients with muscle strength lower than grade 3 so as to replace the conventional passive-type auxiliary device and hence reduce the rehabilitation cost. Also, the auxiliary device of the present invention assists patients who are incapable of controlling their muscles by themselves to effectively train specific muscle groups and prevent involuntary muscle contractions. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a schematic oblique front view of an auxiliary device for muscle strength training according to the present invention; 
           [0014]      FIG. 2  is a schematic oblique rear view of the auxiliary device of the present invention; 
           [0015]      FIG. 3  is a schematic partial assembly view of the auxiliary device of the present invention; 
           [0016]      FIG. 4  is a schematic view showing bonding of the auxiliary device of the present invention to an object; 
           [0017]      FIG. 5  is a schematic view showing a first configuration of the auxiliary device of the present invention; and 
           [0018]      FIG. 6  is a schematic view showing a second configuration of the auxiliary device of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0019]    The following illustrative embodiments are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be apparent to those in the art after reading this specification. 
         [0020]    It should be noted that all the drawings are not intended to limit the present invention. Various modifications and variations can be made without departing from the spirit of the present invention. Further, terms such as “on”, “a” etc. are merely for illustrative purposes and should not be construed to limit the scope of the present invention. 
         [0021]      FIG. 1  is a schematic oblique front view of an auxiliary device  1000  for muscle strength training according to the present invention,  FIG. 2  is a schematic oblique rear view of the auxiliary device  1000  of the present invention and  FIG. 3  is a schematic partial assembly view of the auxiliary device  1000  of the present invention. 
         [0022]    Referring to  FIGS. 1 to 3 , the auxiliary device  1000  has a base  1 , a sliding member  2  slidingly coupled to the base  1 , a connecting-rod mechanism  3  pivotally coupled to the base  1  and the sliding member  2 , and first and second elastic members (not denoted with a reference numeral). 
         [0023]    Referring to  FIG. 3 , the base  1  has a base board  10  having a side  101 , a sliding rail  11 , a support frame  12 , a side board  13  fixed to the side  101  of the base board  10 , and a plurality of first idle wheels  14 . 
         [0024]    The support frame  12  has a first column  121  fixed on the base board  10 , a transverse board  122  fixed on the first column  121 , a second column  123  fixed on the transverse board  122 , an extension board  124  spaced from the transverse board  122  and fixed on the second column  123 , and a triangular fixing board  125  having one side fixed to the base board  10  and another side fixed to the first column  121  so as to improve the bonding effect of the support frame  12  on the base board  10 . The transverse board  122  has a protruding portion  1221  spaced from the base board  10  and extending in a long axis direction of the base board  10 . As such, when viewed from top, the transverse board  122  has a U-shape. The first idle wheels  14  are pivotally disposed on two ends of the extension board  124  and positioned between the protruding portion  1221  of the transverse board  122 . 
         [0025]    The sliding member  2  has a connecting portion  22 , a sliding block  21  fixed to one end of the connecting portion  22  and slidingly disposed on the sliding rail  11  of the base  1 , a first wheel  23  and a second idle wheel  24  pivotally disposed on the other end of the connecting portion  22 . As such, the sliding member  2  has a first end having the sliding block  21  and a second end having the first wheel  23 . 
         [0026]    Referring to  FIGS. 1 and 2 , the connecting-rod mechanism  3  has a first rod  31 , a second rod  32 , a third rod  33 , a fourth rod  34  and a fifth rod  35 . 
         [0027]    The first rod  31  has a sliding slot  311  that allows the first wheel  23  of the sliding member  2  to be slidingly disposed thereon, a first connecting member and an opposite second connecting member  312  at two ends of the first rod  31 , a second wheel  313  pivotally disposed on the protruding portion  1221  of the base  1 , and a third idle wheel  314  disposed inside the first rod  31 . The first rod  31  is rotatable relative to the base  1  through the second wheel  313 . The second rod  32  has a third connecting member  321  at one end thereof and a fourth connecting member  322  at the middle thereof. The third connecting member  321  of the second rod  32  is pivotally connected to the second connecting member  312  of the first rod  31 . The third rod  33  has a fifth connecting member  331  and a sixth connecting member  332  at two ends thereof. The fifth connecting member  331  of the third rod  33  is pivotally connected to the fourth connecting member  322  of the second rod  32 . The fourth rod  34  has a seventh connecting member  341  and an eighth connecting member  344  at two ends thereof, a first connecting portion  342  between the seventh connecting member  341  and the eighth connecting member  344 , and a second connecting portion  343  between the seventh connecting member  341  and the first connecting portion  342 . A fourth idle wheel  345  is disposed on the eighth connecting member  344  and a fifth idle wheel  346  is disposed on the second connecting portion  343 , as shown in  FIG. 2 . The fifth rod  35  has a ninth connecting member  351  and a tenth connecting member  352  at two ends thereof. The ninth connecting member  351  of the fifth rod  35  is pivotally connected to the first connecting portion  342  of the fourth rod  34 , and the tenth connecting member  352  of the fifth rod  35  is pivotally connected to the connecting portion  22  of the sliding member  2  as shown in  FIG. 3 . In the present embodiment, the first rod  31 , the second rod  32 , the third rod  33  and the fourth rod  34  constitute a parallel four-connecting-rod mechanism. But it should be noted that the parallel four-connecting-rod mechanism can be varied according to the practical need and the present invention is not limited thereto. 
         [0028]    Since the first end of the sliding member  2  is slidingly disposed on the sliding rail  11  of the base  1  and the second end of the sliding member  2  is slidingly disposed on the sliding slot  311  of the first rod  31 , the connecting relationship between the base  1  and the connecting-rod mechanism  3  can be changed through the sliding member  2  so as to achieve a reconfigurable mechanism. That is, the present invention allows the auxiliary device  1000  to have a first configuration A and a second configuration B, each of which is used for training a single movement, as shown in  FIGS. 5 and 6 . Further, the auxiliary device  1000  has one degree of freedom due to restriction of relative movements of the above-described components. 
         [0029]    Furthermore, the present invention combines the reconfigurable mechanism with a static balancing mechanism design and uses an energy method for the design. In the present invention, elastic potential energies are generated by elastic members to compensate varied gravitational potential energy during operation of the mechanism, thereby keeping the total potential energy of the mechanism in any configuration at a certain value and hence achieving system balance. Therefore, the present invention uses elastic members to provide elastic potential energies and support a gravitational potential energy of the auxiliary device  1000  and a body, for example, a person, connected to the auxiliary device  1000  to thereby achieve static equilibrium. As such, elastic constants of the elastic members that are required for achieving static equilibrium of the system (i.e., the auxiliary device and the person connected thereto) are calculated based on the rule of static equilibrium, the. In addition, the present invention provides additional rods that are connected to the elastic members. 
         [0030]    The connecting-rod mechanism  3  further has a sixth rod  36  and a seventh rod  37 . The sixth rod  36  has an eleventh connecting member  362  and a twelfth connecting member  361  at two ends thereof, as shown in  FIG. 2 . The eleventh connecting member  362  of the sixth rod  36  is pivotally connected to the side board  13  of the base  1 . The seventh rod  37  has a thirteenth connecting member  371  at the middle thereof, a fourteenth connecting member  372  (shown in  FIG. 2 ) at one end thereof, a sixth idle wheel  373  on the other end thereof and spaced from the fourteenth connecting member  372 , a fixing column  374  between the sixth idle wheel  373  and the thirteenth connecting member  371 , and a block  375  (shown in  FIG. 2 ) between the thirteenth connecting member  371  and the fourteenth connecting member  372 . The thirteenth connecting member  371  of the seventh rod  37  is pivotally connected to the eighth connecting member  344  of the fourth rod  34  and between the first connecting member and the second connecting member  312  of the first rod  31 . The fourteenth connecting member  372  of the seventh rod  37  is pivotally connected to the twelfth connecting member  362  of the sixth rod  36 , as shown in  FIG. 2 . 
         [0031]    Through the above-described additional rods, a first elastic member and a second elastic member are disposed to achieve static equilibrium of the system. 
         [0032]    The first elastic member has a first string  40  and a first spring  41 . The first string  40  slides against the first idle wheel  14  of the base  1 , the second idle wheel  24  of the sliding member  2  (shown in  FIG. 2 ) and the third idle wheel  314  of the first rod  31 . One end of the first string  40  is fixed to a projecting portion  1231  of the second column  123  (shown in  FIG. 2 ), and the other end of the first string  40  is fixed to one end of the first spring  41 . The other end of the first spring  41  is fixed to the base  1 . As such, when the first rod  31  has an angular displacement, the first spring  41  is pulled by the first string  40  to deform. When the extension of the first spring  41  changes, an elastic potential energy is generated or changed to support the gravitational potential energy of the auxiliary device  1000  and the connected body. 
         [0033]    The second elastic member has a second string  50  and a second spring  51 . The second string  50  slides against the fourth idle wheel  345  and the fifth idle wheel  346  of the fourth rod  34  (shown in  FIG. 2 ) and the sixth idle wheel  373  of the seventh rod  37 . One end of the second string  50  is fixed to the fixing column  374  of the seventh rod  37  and the other end of the second string  50  is fixed to one end of the second spring  51 . The other end of the second spring  51  is fixed to the block  375  of the seventh rod  37 . As such, when the second rod  32  has an angular displacement, the second spring  51  is pulled by the second string  50  to deform. When the extension of the second spring  51  changes, an elastic potential energy is generated or changed to support the gravitational potential energy of the auxiliary device  1000  and the connected body. 
         [0034]    In the present embodiment, the first spring  41  and the second spring  51  are, but not limited to, extension springs. 
         [0035]    Referring to  FIG. 4 , the auxiliary device  1000  is further fixed to an object  9  that allows a person to abut against. In the present embodiment, the object  9  is a chair. In particular, the auxiliary device  1000  further has a locking member  8  fixed on the object  9 . The locking member  8  has an extension column  82  fixed on the auxiliary device  1000  and a securing means  81  connecting the extension column  81  and the object  9 . The position of the auxiliary device  1000  relative to the object  9  can be adjusted through the securing means  81  so as to allow the auxiliary device  1000  and the hip joint of the person to be coaxial. The auxiliary device  1000  further has a holding member  7  to be connected with the person. The holding member  7  has a first straight board  73  fixed to the first rod  31 , a second straight board  74  fixed to the second rod  32 , a first holding ring  71  locked to the first straight board  73 , and a second holding ring  72  locked to the second straight board  74 . As such, when the person abuts against the object  9 , a portion of his body is held by the first holding ring  71  and the second holding ring  72 . Therefore, when the person moves the portion of his body, there is a relative movement between the components of the auxiliary device  1000 . Therein, the position of the first holding ring  71  on the first straight board  73  and the position of the second holding ring  72  on the second straight board  74  are adjusted so as to change the length of force arm. Therefore, by changing the bonding position of the body portion, the resistance value can be changed to achieve different muscle strength trainings at different levels. 
         [0036]    Referring to  FIGS. 5 and 6 , as an example, the upper leg of the person is fixed to the first rod  31  through the first holding ring  71  and the lower leg of the person is fixed to the second rod  32  through the second holding ring  72 . The first configuration A is defined by the upper leg movement (i.e., hip flexion/extension) and the second configuration B is defined by the lower leg movement (i.e., knee flexion/extension). In the first configuration A, the first spring  41  provides an elastic potential energy to support the gravitational potential energy of the auxiliary device  1000  and the leg so as to keep the auxiliary device  1000  in static equilibrium. In the second configuration B, the second spring  51  provides an elastic potential energy to support the gravitational potential energy of the auxiliary device  1000  and the leg so as to keep the auxiliary device  1000  in static equilibrium. 
         [0037]    In particular, in the first configuration A, the first wheel  23  of the sliding member  2  is positioned on one end of the sliding slot  311  and coaxial with the second wheel  313 . As such, the first rod  31  is not limited by the height of the sliding member  2  and capable of making an angular displacement W 1  relative to the base  1 . Also, the sliding slot  311  is displaced by an angle due to the rotation of the first rod  31 . Hence, the sliding member  2  cannot move in a first direction D 1 , and there is no relative movement between the sliding member  2  and the base  1 . Further, the relative position of the third, fourth and fifth rods  33 ,  34 .  35  is fixed by the sliding member  2 . That is, there is no relative movement between the third, fourth and fifth rods  33 ,  34 .  35 . As such, there is no angular displacement occurring to the second rod  32 . Therefore, the auxiliary device  1000  is kept in the first configuration A. The first angular displacement W 1  of the first rod  31  causes the first string  40  to pull the first spring  41 . When the extension of the first spring  41  changes, an elastic potential energy is generated or changed to support the gravitational potential energy of the auxiliary device  1000  and the leg, thus achieving a muscle strength training effect on the upper leg. 
         [0038]    In addition, in the first configuration A, the fourth rod  34  and the seventh rod  37  are collinear with the second spring  51  and there is no significant deformation occurring to the second spring  51 . Therefore, in the first configuration A, the extension of the second spring  51  will not be changed by the angular displacement W 1  of the first rod  31 , and the second spring  51  does not influence the static equilibrium of the system. 
         [0039]    In the second configuration B, the first rod  31  is substantially at a horizontal position relative to the base  1 . The sliding member  2  is slidable along the sliding slot  311  in the first direction D 1 , and the first rod  31  is limited by the height of the sliding member  2  and kept a fixed distance from the base  1 . As such, there is no significant relative rotation between the first rod  31  and the base  1 , and sliding of the sliding member  2  along the sliding slot  311  causes the second rod  32  to make a second angular displacement W 2  relative to the first rod  31 . Therefore, the auxiliary device  1000  is kept in the second configuration B. The second angular displacement W 2  of the second rod  32  causes the second string  50  to pull the second spring  51 . When the extension of the second spring  51  changes, an elastic potential energy is generated or changed to support the gravitational potential energy of the auxiliary device  1000  and the leg, thus achieving a muscle strength training effect on the lower leg. 
         [0040]    In addition, in the second configuration B, the first rod  31  is substantially at a horizontal position relative to the base  1  and there is no significant movement therebetween. Therefore, in the second configuration B, the extension of the first spring  41  will not be changed by the angular displacement W 2  of the second rod  32 , and the first spring  41  does not influence the static equilibrium of the system. 
         [0041]    Therefore, the present invention provides an active-type auxiliary device for muscle strength training based on a static balancing mechanism design in combination with a reconfigurable mechanism. The auxiliary device has one degree of freedom due to restriction of relative movements of the rods in the connecting-rod mechanism. Furthermore, a spring connected to the connecting-rod mechanism provides an elastic potential energy to support a total gravitational potential energy of the auxiliary device and a human body connected to the auxiliary device so as to reach static equilibrium. As such, the auxiliary device of the present invention is applicable for patients with muscle strength lower than grade 3 so as to replace the conventional passive-type auxiliary device and hence reduce the rehabilitation cost. Also, the auxiliary device of the present invention assists patients who are incapable of controlling their muscles by themselves to effectively train specific muscle groups and prevent involuntary muscle contractions. 
         [0042]    Further, the upper leg and the lower leg of a person are indirectly fixed to the first rod and the fourth rod of the auxiliary device, respectively. In the first configuration, the first rod is rotatable relative to the base and there is no relative movement between the second rod and the first rod, thus achieving a muscle strength training effect on the upper leg. Further, in the second configuration, there is no relative movement between the first rod and the base and the second rod is rotatable relative to the first rod, thus achieving a muscle strength training effect on the lower leg. 
         [0043]    Furthermore, the active-type auxiliary device of the present invention is simple in construction. To adjust the resistance value of the auxiliary device, the present invention does not need to change elastic members or perform complicated operations to adjust relative positions of internal components of the auxiliary device as in the prior art, thereby improving the convenience in use of the active-type auxiliary device. 
         [0044]    The above-described descriptions of the detailed embodiments are only to illustrate the preferred implementation according to the present invention, and it is not to limit the scope of the present invention. Accordingly, all modifications and variations completed by those with ordinary skill in the art should fall within the scope of present invention defined by the appended claims.