JP2011098014A - Ankle foot orthosis - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ankle foot orthosis in which a damper does not need to oscillate. <P>SOLUTION: The ankle foot orthosis 10 includes a lower thigh member 12 worn around the lower thigh of a user, a foot member 14 worn around the foot of the user, the damper 40, and a coupling mechanism 20. The foot member 14 is oscillatably coupled with the lower thigh member 12. The damper 40 provides viscosity elastic by a movable end moving. The damper 40 is fixed to the lower thigh member 12, and the movable end moves along the lower thigh in the longitudinal direction when the lower thigh member 12 is worn by the user. The coupling mechanism 20 couples the foot member 14 to the movable end of the damper 40. The coupling mechanism 20 moves the movable end of the damper 40 interlocking with the oscillation of the foot member 14. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ankle foot orthosis (AFO).

  A short leg brace is known as an auxiliary device for users who cannot move their legs freely. The short leg brace includes a leg member fixed to the user's lower leg and a foot member fixed to the foot. As used herein, “lower leg” means a portion between a knee and an ankle. “Foot” means a portion ahead of the ankle joint. In some short leg braces, a foot member is swingably connected to the lower leg member, and a damper and / or a spring is connected between the lower leg member and the foot member. Dampers and springs relieve the load on the ankle during walking. An example of a short leg brace is disclosed in Patent Document 1.

Japanese Patent No. 4156909

  When one end of the damper is swingably connected to the lower leg member and the other end of the damper is swingably connected to the foot member, the damper swings in conjunction with the swing of the foot member. Become. Although it is desirable that the short leg brace is compact, the conventional short leg brace has to secure a space for the damper to swing. The technology disclosed in this specification provides a short leg brace that does not require the damper to swing. According to the technique disclosed in this specification, it is not necessary to secure a space that allows the damper to swing, and a compact short leg brace can be realized.

  One technique disclosed in the present specification provides a short leg brace in which a damper does not swing. The short leg brace includes a leg member attached to the user's leg, a foot member attached to the user's foot, a damper fixed to the leg member, and a coupling mechanism. The foot member is pivotally connected to the crus member. The damper has a movable end that provides viscous resistance by moving. The movable end can move along the longitudinal direction of the lower leg when the lower leg member is attached to the user. The connection mechanism connects the foot member to the movable end of the damper. The coupling mechanism moves the movable end of the damper in conjunction with the swing of the foot member. By providing such a coupling mechanism, this novel short leg brace implements fixing the damper to the leg member.

  A preferred example of the specific structure of the coupling mechanism includes a guide block and a link. The guide block is attached to the movable end of the damper. The guide block has a guide groove or a guide rail that extends in the front-rear direction of the user when the short leg brace is worn by the user. The lower end of the link is fixed to the foot member, and the upper end is slidably engaged with the guide groove or the guide rail.

  In the connection mechanism having such a structure, the link swings together with the foot member. When the link swings, the upper end of the link moves along the arc. As the link swings, the link engaged with the guide groove or the guide rail moves the guide block linearly along the longitudinal direction of the lower leg. That is, the damper fixed to the lower leg member functions by the above-described coupling mechanism.

  Another technique disclosed in the present specification provides a short leg brace that can more effectively assist a user's walking motion. The short leg orthosis assists the plantar flexion of the foot when landing, and assists the motion of the foot to support its own weight. Such a short leg brace includes a spring unit in addition to the above-described damper. The spring unit connects the lower leg member and the guide block. The spring unit is connected in parallel with the damper between the lower leg member and the guide block.

  The damper imparts viscous resistance when the guide block moves in one direction in conjunction with the swing from the neutral position of the foot member to the bottom flexion direction. Viscous resistance is imparted to the foot member via the coupling mechanism. On the other hand, the damper does not give viscous resistance when the guide block moves in the reverse direction in conjunction with the swing of the foot member in the dorsiflexion direction. This damper is a so-called one-way damper that gives a viscous resistance when the movable end moves in one direction and does not give a viscous resistance when the movable end moves in the opposite direction. Furthermore, this damper does not give viscous resistance to swinging in any direction when the movable end is located on the dorsiflexion side from the neutral position. Such a one-way damper is typically realized by a structure that moves the viscous material of the damper when the movable end moves in one direction from the neutral position and separates from the viscous material when moved in the opposite direction. The “neutral position” is individually adjusted according to the user, and corresponds to the position of the foot member when the foot member is substantially orthogonal to the lower leg member, for example. An example of a specific structure of the damper will be described later.

  In walking movement, after the heel touches the ground, the foot bends from the neutral position, and the entire sole of the foot contacts the ground. The above one-way damper assists the plantar flexion movement after the heel touches the ground.

  The spring unit does not apply a spring force when the guide block moves in one direction in conjunction with the swinging from the neutral position of the foot member in the bottom bending direction. On the other hand, the spring unit applies a spring force when the guide block moves in the reverse direction in conjunction with the swing from the neutral position of the foot member to the dorsiflexion direction. On the dorsiflexion side from the neutral position, the spring unit applies a spring force to swinging in any direction. The spring force is applied to the foot member via the coupling mechanism. Such a spring unit is typically realized by a structure that moves away from the spring body when the end of the spring unit moves in one direction and moves the spring body when moved in the opposite direction.

  After one leg touches the ground, the other leg swings forward and the trunk moves forward, so that the leg buckles beyond the neutral position. The foot flexes toward the neutral position when it leaves. The spring unit described above assists a series of foot movements until the ground is released.

  In the connection mechanism, the slide range at the upper end of the link is preferably behind the rotation axis of the foot member. Here, “behind the rotation axis” means “behind the rotation axis” along the user's front-rear direction when the user attaches the short leg brace. In the short leg brace, the shin side of the leg member is usually referred to as “front”. By laying out the guide block and the link of the coupling mechanism in that way, the damper and the spring unit can be operated more effectively. That is, in the above layout, the stroke Sp of the guide block when the foot member swings the angle Ap from the neutral position in the bottom bending direction and the guide block when the foot member swings the angle Ad from the neutral position to the dorsiflexion direction. The stroke Sd satisfies the relationship Sp / Ap <Sd / Ad. The short leg brace that satisfies such a relationship can operate the spring unit with a relatively long stroke, and conversely, can operate the damper with a relatively short stroke. If the spring constant is the same, a spring having a long stroke can have a smaller diameter than a spring having a short stroke. Also, a damper with a short stroke is less expensive than a damper with a long stroke if the viscous resistance is the same. Such a relationship can be realized with several geometric arrangements of guide blocks and links. The reason why the layout satisfies the relationship between the swing range and the stroke will be described in the embodiment.

  As described above, the novel technique disclosed in this specification provides a short leg brace that is superior to the conventional art.

It is a schematic diagram of the short leg brace of an Example. It is a figure explaining the relationship between the rocking | fluctuation angle of a link, and the stroke of a spring / damper. It is a schematic diagram of the short leg brace of other embodiment.

  A short leg brace according to an embodiment will be described with reference to the drawings. FIG. 1: has shown the schematic diagram of the short leg apparatus 10 of 1st Example. Hereinafter, for the sake of simplicity, the “short leg brace 10” is abbreviated as “AFO10”. The AFO 10 includes a crus member 12, a foot member 14, a joint 16, a one-way damper 40, a one-way spring unit 50, a coupling mechanism 20, and a linear guide 30 as main components. As shown in FIG. 1, the one-way damper 40, the one-way spring unit 50, and the connecting mechanism 20 are attached to the crus member 12 so as to be positioned on the side of the crus R when the user wears the AFO 10. ing.

  The foot member 14 is pivotably connected to the crus member 12 by a joint 16. The lower leg member 12 is attached to the lower leg R of the user. The foot member 14 is attached to the user's foot F. When the user wears the AFO 10, the joint 16 is positioned substantially coaxially with the user's ankle joint. When the user swings the foot in the bottom bending direction or the dorsiflexion direction, the foot member 14 also swings. 1 indicates the rotational axis of the joint 16. The angle of the ankle joint shown in FIG.1, that is, when the foot F and the lower leg R are substantially perpendicular, corresponds to the neutral position of the foot member 14. The “neutral position” is individually adjusted according to the user.

  The one-way damper 40 and the one-way spring unit 50 are fixed to the crus member 12. First, the one-way damper 40 will be described. The one-way damper 40 includes a viscous material 41, a case 42, and a piston rod 44. The case 42 is fixed to the crus member 12. A viscous material 41 is disposed in the case 42. The lower end of the piston rod 44 is connected to a guide block 22 described later, and when the guide block 22 moves up and down along the longitudinal direction of the lower leg R, the piston rod 44 also moves up and down. The longitudinal direction of the lower leg R corresponds to the vertical direction in FIG. In the state of FIG. 1, the upper end of the piston rod 44 is in contact with the viscous material 41. As will be described in detail later, when the foot F swings in the dorsiflexion direction, the guide block 22 linearly moves downward, and when the foot F swings in the bottom flexion direction, the guide block 22 moves linearly upward. The guide block 22 will be described in detail later.

  The viscous material 41 is made of a compressible material. The natural length of the viscous material 41 is L1, and the upper end of the piston rod 44 contacts the viscous material 41 when the foot member 14 is just in the neutral position. The viscous material 41 and the piston rod 44 are only in contact with each other and are not fixed to each other. When the guide block 22 moves upward from the state shown in FIG. 1, the piston rod 44 compresses the viscous material 41. At this time, the viscous material 41 gives viscous resistance to the movement of the piston rod 44. When the guide block 22 moves downward from the state shown in FIG. 1, the upper end of the piston rod 44 moves away from the viscous material 41. When the guide block 22 moves downward, the viscous material 41 does not impart viscous resistance to the piston rod 44. The lower end of the piston rod 44 corresponds to the movable end of the one-way damper 40.

  The one-way damper 40 provides viscous resistance when the guide block 22 moves upward from the neutral position. The one-way damper 40 does not apply viscous resistance to the piston rod 44 when the guide block 22 moves downward from the neutral position. Further, the one-way damper 40 does not give viscous resistance when the piston rod 44 once moves upward and then moves downward again.

  Next, the one-way spring unit 50 will be described. The one-way spring unit 50 includes a spring 54, a stopper 56, and a piston rod 58. The stopper 56 is fixed to the crus member 12. The stopper 56 is provided with a hole through which the piston rod 58 passes. A rib 58 a is provided at the upper end of the piston rod 58. A spring 54 is inserted between the rib 58 a and the stopper 56. The lower end of the piston rod 58 is connected to the guide block 22. The lower end of the piston rod 58 corresponds to the movable end of the one-way spring unit 50.

  The piston rod 58 is guided by the linear guide 30 and can move linearly up and down along the longitudinal direction of the lower leg R. That is, the linear guide 30 supports the piston rod 58 so as to be slidable along the longitudinal direction thereof. The natural length of the spring 54 is L2, and when the foot member 14 is just in the neutral position, the distance between the rib 58a of the piston rod 58 and the stopper 56 is also L2. Note that the strength of the restoring force in the vicinity of the neutral position can be adjusted by intentionally compressing the spring 54 (for example, arranging a spacer between the rib 58a and the stopper 56). When the guide block 22 moves downward from the state shown in FIG. 1, the space between the rib 58a and the stopper 56 is contracted, and the spring 54 is compressed. At this time, the spring 54 applies a spring force (restoring force) to the guide block 22 via the piston rod 58. The rib 58a and the spring 54 are only in contact with each other, and are not fixed to each other. Therefore, when the guide block 22 moves upward from the state of FIG. 1, the distance between the rib 58a and the stopper 56 becomes larger than the distance L2, and the rib 58a and the spring 54 are separated. When the guide block 22 moves upward from the state of FIG. 1, the spring 54 does not apply a spring force to the guide block 22.

  Next, the connection mechanism 20 will be described. The coupling mechanism 20 mainly includes a guide block 22 and a link 28. The guide block 22 is connected to the movable end of the one-way spring unit 50 (the tip of the piston rod 58), and can move up and down along the longitudinal direction of the lower limb R while being guided by the linear guide 30. The guide block 22 is connected to the movable end of the one-way damper 40 but is guided mainly by the linear guide 30. The guide block 22 is formed with a guide groove 22a extending in the front-rear direction of the user.

  The lower end of the link 28 is fixed to the foot member 14, and the upper end of the link 28 is engaged with the guide groove 22 a via the cam follower 26. The link 28 swings around the rotation axis C. At this time, the upper end of the link 28 slides along the guide groove 22a.

  The symbol “V” in FIG. 1 represents a straight line that passes through the rotation axis C of the joint 16 (the rotation axis of the foot member 14) and extends along the longitudinal direction of the crus member 12. In other words, the straight line V represents a straight line that extends along the longitudinal direction of the user's lower leg through the rotation axis C when the user wears the AFO 10. As shown in FIG. 1, the slide range at the upper end of the link 28 is located behind the straight line V. Such an arrangement has a special effect. The effect will be described later.

  The operation of the coupling mechanism 20 will be described. As described above, the state of FIG. 1 shows a state in which the foot member 14 is in the neutral position. At this time, the length of the viscous material 41 is the natural length L1, and the length of the spring 54 is the natural length L2.

  When the user swings the foot F in the bottom bending direction, the foot member 14 also swings in the bottom bending direction. The plantar flexion direction corresponds to the rotation direction of the ankle joint in the direction in which the toes are lowered. The dorsiflexion direction corresponds to the rotation direction of the ankle joint in the direction in which the toes rise. The arrow P in FIG. 1 indicates the bottom bending direction, and the arrow D indicates the dorsiflexion direction. When the foot member 14 swings in the bottom bending direction, the link 28 fixed to the foot member 14 swings in the direction of the arrow p. The position of the upper end of the link 28 goes up. The guide block 22 is engaged with the upper end of the link 28, and the upper end of the link 28 pushes up the guide block 22 while sliding along the guide groove 22a. At this time, the viscous material 41 is compressed via the piston rod 44. As the guide block 22 moves upward, the viscous material 41 imparts viscous resistance to the foot member 14 via the piston rod 44 and the coupling mechanism 20. On the other hand, when the foot member 14 swings from the neutral position in the bottom bending direction, the guide block 22 is pushed up by the coupling mechanism 20 and the piston rod 58 moves upward. The distance between the rib 58a of the one-way spring unit 50 and the stopper 56 is larger than L2, but at this time, the spring 54 is separated from the rib 58a and does not apply a spring force.

  On the other hand, when the user swings the foot F from the neutral position in the dorsiflexion direction (the direction of arrow D), the foot member 14 also swings in the dorsiflexion direction. When the foot member 14 swings in the dorsiflexion direction, the link 28 fixed to the foot member 14 swings in the direction of the arrow d. The position of the upper end of the link 28 is lowered. The upper end of the link 28 pushes down the guide block 22 while sliding along the guide groove 22a. At this time, the piston rod 58 moves downward. The distance between the rib 58a of the one-way spring unit 50 and the stopper 56 is shorter than L2, and the spring 54 is compressed. For this reason, the one-way spring unit 50 applies a spring force that swings the foot member 14 in the bottom bending direction.

  The operation of the AFO 10 is summarized as follows. The one-way damper 40 and the one-way spring unit 50 are attached to the crus member 12. The one-way damper 40 and the one-way spring unit 50 are coupled in parallel between the crus member 12 and the coupling mechanism 20. When the guide block 22 of the coupling mechanism 20 moves along the longitudinal direction of the lower leg R, the movable ends of the one-way damper 40 and the one-way spring unit 50 also move along the longitudinal direction of the lower leg R. The one-way damper 40 imparts viscous resistance to the foot member 14 when the guide block 22 moves upward in conjunction with the swing from the neutral position of the foot member 14 to the bottom bending direction. The one-way damper 40 does not impart viscous resistance to the foot member 14 when the guide block 22 moves downward in conjunction with the swinging of the foot member 14 in the dorsiflexion direction. The one-way spring unit 50 does not apply a spring force to the foot member 14 when the guide block 22 moves upward in conjunction with the swing from the neutral position of the foot member 14 to the bottom bending direction. When the guide block 22 moves downward in conjunction with swinging in the dorsiflexion direction from the neutral position, a spring force is applied to the foot member 14.

  The one-way damper 40 and the one-way spring unit 50 are fixed to the crus member 12, and they do not swing even if the foot member 14 swings. The fact that the one-way damper 40 and the one-way spring unit 50 do not swing is achieved by the structure of the coupling mechanism 20 described above. According to the above configuration, since the one-way damper 40 and the one-way spring unit 50 can be fixed to the crus member 12, a compact AFO 10 can be realized. In particular, since the one-way damper 40 and the one-way spring unit 50 can be arranged in parallel along the longitudinal direction of the crus member 12, they can be laid out compactly.

  Next, the further effect which the said connection mechanism 20 show | plays is demonstrated. The effect is attributed to the configuration in which the slide range at the upper end of the link 28 is located behind the straight line V (see FIG. 1). The coupling mechanism 20 can effectively use a spring and a damper. FIG. 2 shows the magnitude of the stroke Sp of the guide block 22 when the foot member 14 swings from the neutral position in the bottom bending direction, and when the foot member 14 swings the angle Ad from the neutral position in the dorsiflexion direction. The magnitude of the stroke Sd of the guide block 22 is shown. A point C in the upper diagram of FIG. 2 corresponds to the rotation axis of the joint 16. The X axis corresponds to the longitudinal direction of the foot member 14. The positive direction of the X axis corresponds to the toe direction. The Y axis corresponds to the longitudinal direction of the crus member 12. That is, the Y axis corresponds to the straight line V in FIG. Point P1 indicates the position of the upper end of the link 28 when the foot member 14 is in the neutral position. The angle An represents the angle formed by the longitudinal direction of the foot member 14 and the link 28. When the foot member 14 swings the angle Ap from the neutral position in the bottom bending direction, the upper end of the link 28 is located at the point P2. The distance Sp represents a stroke of the guide block 22 when the foot member 14 swings by an angle Ap in the bottom bending direction from the neutral position. When the foot member 14 swings by an angle Ad in the dorsiflexion direction from the neutral position, the upper end of the link 28 is positioned at the point P3. The distance Sd represents a stroke of the guide block 22 when the foot member 14 swings by an angle Ad in the dorsiflexion direction from the neutral position.

  The lower graph in FIG. 2 shows changes in Sd / Ad and Sp / Ap when the attachment angle An of the link 28 is changed. The link length was 1.0 and the angle Ad = Ap = 20 [deg] was used for calculation. Sp / Ap represents the stroke Sp of the guide block 22 when the foot member 14 swings the angle Ap in the bottom bending direction. Sd / Ad represents the stroke Sd of the guide block 22 when the foot member 14 swings by an angle Ad in the dorsiflexion direction. The larger the absolute value of S / A, the larger the stroke with respect to the swing of the unit angle. 2, the stroke of the guide block 22 becomes relatively large with respect to the swinging of the foot member 14 in the dorsiflexion direction, and conversely, the guide with respect to the swinging of the foot member 14 in the bottom flexion direction. The stroke of the block 22 is relatively small.

  That is, if the slide range of the upper end of the link 28 is within the range W1, the one-way spring unit 50 can be operated with a relatively long stroke, and conversely, the one-way damper 40 can be operated with a relatively short stroke. it can. If the spring constant is the same, a spring having a long stroke can have a smaller diameter than a spring having a short stroke. Also, a damper with a short stroke is less expensive than a damper with a long stroke if the viscous resistance is the same. Therefore, if the coupling mechanism 20 is configured so that the slide range of the upper end of the link 28 is in the range of W1, an AFO that efficiently uses the spring and the damper can be realized.

  The above layout basically corresponds to a configuration in which the slide range at the upper end of the link 28 is located behind the rotation axis C of the foot member 14 when the user wears the AFO 10. As described above, the point C in FIG. 2 corresponds to the rotation axis of the joint 16, and the axis Y corresponds to the longitudinal direction of the crus member 12. The axis Y is a straight line that extends along the lower leg member 12 through the rotation axis C of the joint 16. Therefore, the above-described configuration of the coupling mechanism 20 can be further described as follows. That is, the swing range of the link 28 is behind the straight line V (Y axis) extending along the lower leg through the rotation axis C and above the straight line (X axis) intersecting the straight line V through the rotation axis C. It is. Or, roughly speaking, the above-described configuration corresponds to a configuration in which the link 28 extends from the joint 16 connecting the lower leg member 12 and the foot member 14 to the rear side of the lower leg. That is, if the connecting mechanism 20 is configured so that the link 28 extends from the joint 16 connecting the lower leg member 12 and the foot member 14 toward the rear of the lower leg, the above-described effect can be obtained.

  Here, in the AFO 10 described above, the upper end of the link 28 is guided by the guide groove 22 a of the guide block 22 and moves in the front-rear direction with respect to the guide block 22. Therefore, a moment is applied to the guide block 22 according to the position of the upper end of the link 28 in the front-rear direction. At this time, if a large moment is applied to the guide block 22, the vertical movement of the guide block 22 is hindered. In order to reduce such a moment, the arrangement of the one-way damper 40 and the one-way spring unit 50 may be determined according to the movement range of the upper end of the link 28 with respect to the guide block 22. Specifically, the one-way damper 40 and the one-way spring unit 50 may be respectively disposed at the movement limit in the front-rear direction of the upper end of the link 28 (that is, both end positions of the movement range). According to this configuration, the moment applied to the guide block 22 can be significantly reduced. As a result, for example, a small linear guide 30 can be employed.

Next, the AFO 110 of the second embodiment will be described with reference to FIG. The AFO 110 according to the second embodiment includes a one-way damper 140, two one-way spring units 150a and 150b, and a linear guide 130. The structures of the one-way damper 140, the one-way spring units 150a and 150b, and the linear guide 130 are the same as those of the one-way damper 140, the one-way spring unit 50, and the linear guide 130 of the first embodiment. However, the linear guide 130 is provided in the one-way damper 140 and guides the piston rod 144.
In the AFO 110 of this embodiment, a linear guide 130 is provided on the one-way damper 140, and one-way spring units 150a and 150b are arranged on both sides thereof. Here, the two one-way spring units 150a and 150b have the same distance from the linear guide 130 and are disposed symmetrically with the one-way damper 140 as the center. As described above, when the plurality of one-way spring units 150a and 150b are arranged symmetrically with respect to the linear guide 130 that guides the guide block 22, the moment applied to the guide block 22 can be reduced. The one-way spring units 150 a and 150 b are not limited, and a plurality of one-way dampers 140 may be arranged symmetrically (equal distance) with respect to the linear guide 130.

  Points to be noted regarding the AFO of the above-described embodiment will be described. The AFOs 10 and 110 of the embodiment include both the one-way dampers 40 and 140 and the spring units 50, 150a, and 150b, but may include only one of them. In the AFOs 10 and 110 according to the embodiment, the upper end of the link 28 of the coupling mechanism 20 is engaged with the guide groove 22 a of the guide block 22. Even if a guide rail is adopted instead of the guide groove 22a, the same effect can be obtained. The AFO 110 according to the second embodiment includes two one-way spring units 150a and 150b. Here, even if two one-way dampers 140 are provided instead of the two one-way spring units 150a and 150b, the same effect can be obtained.

  The AFO 10 according to the embodiment includes a one-way damper 40 and a one-way spring unit 50. The one-way damper 40 gives a viscous resistance when the guide block 22 moves in one direction in conjunction with the swing from the neutral position of the foot member 14 to the bottom bending direction, and the foot member 14 swings in the dorsiflexion direction. When the guide block 22 moves in the reverse direction in conjunction with the movement, no viscous resistance is applied. The one-way spring unit 50 does not apply a spring force when the guide block 22 moves in one direction in conjunction with the swing in the bottom bending direction from the neutral position of the foot member 14, and from the neutral position of the foot member 14. A spring force is applied when the guide block 22 moves in the reverse direction in conjunction with swinging in the dorsiflexion direction. A sub-damper may be provided in addition to the one-way damper 40. The sub damper operates in the opposite direction to the one-way damper 40. That is, the sub damper does not give viscous resistance when the guide block 22 moves in one direction in conjunction with the swing from the neutral position of the foot member 14 to the bottom bending direction, and does not swing the foot member 14 in the dorsiflexion direction. When the guide block 22 moves in the reverse direction in conjunction with the movement, viscous resistance is applied. Further, a sub spring unit may be provided in addition to the one-way spring unit 50. The sub spring unit operates in the opposite direction to the one-way spring unit 50. That is, the sub-spring unit applies a spring force when the guide block 22 moves in one direction in conjunction with the swing in the bottom bending direction from the neutral position of the foot member 14, and from the neutral position of the foot member 14. When the guide block 22 moves in the reverse direction in conjunction with the swing in the dorsiflexion direction, no spring force is applied. Of course, it is preferable that the viscous resistance of the sub-damper is smaller than that of the one-way damper 40, and the spring constant of the sub-spring unit is smaller than the spring constant of the one-way spring unit 50.

  Points to be noted of the technology disclosed in this specification will be described. A first object of the technology disclosed in the present specification is to provide an AFO in which a damper and / or a spring does not swing. The object is achieved by the AFO having the above-described coupling mechanism. The first object is achieved even if the AFO has a normal damper instead of a one-way damper. A secondary object of the technology disclosed in this specification is to provide an AFO that effectively operates a damper and a spring. The secondary purpose is achieved by the movement range of the upper end of the link existing behind the rotation axis of the joint 16 when the user wears the AFO.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

10, 110: Ankle foot orthosis (AFO)
12: Leg member 14: Foot member 16: Joint 20: Connection mechanism 22: Guide block 22a: Guide groove 28: Link 30, 130: Linear guide 40, 140: One-way damper 41: Viscous material 42: Case 44, 144: Piston Rod 50, 150a, 150b: One-way spring unit 54: Spring 56: Stopper 58: Piston rod 58a: Rib

Claims (4)

A lower leg member to be worn on the user's lower leg;
A foot member to be attached to a user's foot, and a foot member that is swingably coupled to the lower leg member;
A damper that imparts viscous resistance by moving the movable end, and is fixed to the crus member, and when the crus member is attached to the user, the movable end moves along the longitudinal direction of the crus;
A short limb orthosis comprising a coupling mechanism that couples a foot member to a movable end of a damper and moves the movable end of the damper in conjunction with the swing of the foot member. The coupling mechanism is
A guide block attached to the movable end of the damper and having a guide groove or a guide rail extending in the front-rear direction of the user when the short leg brace is attached to the user;
A link having a lower end fixed to the foot member and an upper end slidably engaged with a guide groove or a guide rail;
The short leg prosthesis according to claim 1, comprising: It is a spring unit that connects the lower leg member and the guide block, and has a spring unit that is connected in parallel with the damper,
The damper provides viscous resistance when the guide block moves in one direction in conjunction with the swing from the neutral position of the foot member to the bottom flexion direction, and interlocks with the swing of the foot member in the dorsiflexion direction. This is a one-way damper that does not give viscous resistance when the guide block moves in the opposite direction,
The spring unit does not apply spring force when the guide block moves in one direction in conjunction with swinging from the neutral position of the foot member to the bottom flexion direction, and from the neutral position of the foot member to the dorsiflexion direction. The short leg brace according to claim 2, wherein a spring force is applied when the guide block moves in the reverse direction in conjunction with the swing of the leg.   The short limb orthosis according to claim 3, wherein the coupling mechanism is configured such that the slide range of the upper end of the link is located behind the rotation axis of the foot member.

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