Knee brace and leg brace

1. A knee brace for a knee osteoarthritis patient, the knee brace comprising:

a thigh fixing part that is configured to be attached to a thigh of a patient, the thigh fixing part including a thigh cuff and a thigh belt;

a shank fixing part that is configured to be attached to a shank of the patient, the shank fixing part including a shank cuff and a shank belt;

an outer leg joint that couples the thigh fixing part with the shank fixing part, is arranged in an outer leg side of a knee joint of the patient, and can be flexed; and

an inner leg joint that couples the thigh fixing part with the shank fixing part, is arranged in an inner leg side of the knee joint of the patient, and can be flexed, wherein

each of the outer leg joint and the inner leg joint includes a coupling part, an upper arm that is provided along a side part of the thigh and a lower arm that is provided along a side part of the shank,

the upper arm and the lower arm of the outer leg joint are coupled to each other by the coupling part of the outer leg joint that is provided in a side part of the knee joint,

the upper arm and the lower arm of the inner leg joint are coupled to each other by the coupling part of the inner leg joint that is provided in a side part of the knee joint,

the lower arm of the outer leg joint is configured to be moved forward relative to the lower arm of the inner leg joint when the outer leg joint and the inner leg joint are extended, and

the coupling part of each of the outer leg joint and the inner leg joint comprises a cam groove provided in one of the upper arm and the lower arm and a long groove provided in the other of the upper arm and the lower arm, the cam groove including an intermediate cam groove forming an acute angle between a flexing-side cam groove and an extending-side cam groove of the cam groove,

wherein the long groove in the outer leg joint is provided rearward of the cam groove and an upper end of the long groove in the outer leg joint is provided forward of an opposite lower end of the long groove when the upper arm and the lower arm of the outer leg joint are in an extended state,

wherein the long groove in the inner leg joint is provided forward of the cam groove and an upper end of the long groove in the inner leg joint is provided forward of an opposite lower end of the long groove when the upper arm and the lower arm of the outer leg joint are in an extended state.

2. The knee brace according to claim 1 , wherein

the coupling part of each of the outer leg joint and the inner leg joint comprises:

a rotation fulcrum shaft that is provided in the upper arm or the lower arm and is slid in the long groove; and

a cam shaft that is provided in the lower arm or the upper arm and is slid in the cam groove, and

when the patient flexes the knee joint, the lower arm is configured to be rotated with respect to the upper arm along with the rotation fulcrum shaft sliding in the long groove and the cam shaft sliding in the cam groove.

3. The knee brace according to claim 2 , wherein the coupling part of each of the outer leg joint and the inner leg joint comprises:

the cam groove is provided in the upper arm,

the long groove is provided in the lower arm,

the rotation fulcrum shaft is provided in the upper arm, and

the cam shaft is provided in the lower arm.

4. The knee brace according to claim 3 , wherein

the long groove of the lower arm of the outer leg joint is inclined with respect to a longitudinal direction of the lower arm in such a way that an end part of the long groove where the rotation fulcrum shaft is provided when the outer leg joint is extended is positioned posterior with respect to a second end of the long groove, and

the long groove of the lower arm of the inner leg joint is inclined with respect to the longitudinal direction of the lower arm in such a way that the end part of the long groove where the rotation fulcrum shaft is provided when the inner leg joint is extended is positioned anterior with respect to a second end of the long groove.

5. The knee brace according to claim 1 , wherein the knee brace is configured so that the extended state of the knee joint is not released by a ground reaction force when a diseased leg to which the knee brace is attached contacts the ground.

6. The knee brace according to claim 1 , wherein

the coupling part of each of the outer leg joint and the inner leg joint comprises:

a long groove provided in the lower arm or the upper arm;

a rotation fulcrum shaft that is provided in the upper arm or the lower arm and is slid in the long groove; and

a cam shaft that is provided in the lower arm or the upper arm and is slid in the cam groove, wherein

when the patient flexes the knee joint, the lower arm is configured to be rotated with respect to the upper arm along with the rotation fulcrum shaft sliding in the long groove and the cam shaft sliding in the cam groove, and

an area of the cam groove where the cam shaft is positioned when the knee joint is in the extended state is orthogonal to a longitudinal direction of the upper arm, or

the area of the cam groove of the outer leg joint is inclined in such a way that it goes downward toward an end part of the cam groove on the extending side, or

the area of the cam groove of the inner leg joint is inclined in such a way that it goes upward toward the end part of the cam groove on the extending side.

7. The knee brace according to claim 1 , further comprising an energizing part which includes a cylindrical body that energizes the outer leg joint and the inner leg joint in such a way that they approach each other.

8. A leg brace comprising the knee brace according to claim 1 .