Abstract: The invention relates to a prosthetic joint which can be used as an artificial knee. Said prosthetic joint consists of a knee upper part (1), a knee lower part (2) and a fixing element (8) connecting said two lower parts. The knee upper part is rotationally arranged about the rotational axis (4) of the fixing element and rotation occurs counter to the force of an elastic element (17) which is arranged in knee lower part. Detachable fixing means (7), which are used to fix at least one rotational position, are provided between the knee upper part and the fixing element.

Abstract: A tetraxial-link artificial limb joint includes a kneecap, front connection boards, a rear connection rod, a first axis, a second axis, a third axis, a fourth axis, and a shank connection seat. The point for force acting is below these four axes, thereby forming an inverse triangular therebetween. The inverse triangular is maintained to not bend the artificial limb joint until the user's forefoot land down again for each step.

Abstract: A tetraxial-link artificial limb joint includes a kneecap, front connection boards, a rear connection rod, a first axis, a second axis, a third axis, a fourth axis, and a shank connection seat. The point for force acting is below these four axes, thereby forming an inverse triangular therebetween. The inverse triangular is maintained to not bend the artificial limb joint until the user's forefoot land down again for each step.

Abstract: The present invention provides an improved structure of a knee joint stressing device, which comprises a main body and a turning shaft. The main body is screwed to the turning shaft through an inner thread. The root of the thread is used as a lubricant storing space so that lubricant can exist on the contact surface more easily. Moreover, the thread surface is used to increase the contact area, hence reducing abrasion between components, extending lifetime, saving unnecessary components, and lowering the manufacturing cost.