Abstract: An artificial knee joint includes a four-bar linkage, an extension bar having a first end pivotally connected to the four-bar linkage, and a restoring device connected to a bottom of the four-bar linkage and comprising a transmission rod having a first end pivotally connected to and retractably moving a second end of the extension bar. The four-bar linkage includes a first, second, third, and fourth connecting bar, any two adjacent connecting bars of which are connected together by their respective pivot axles. When the four-bar linkage is moved to a locked state, a specific included angle is defined between any two adjacent straight lines joining adjacent pivot axles of the four-bar linkage. While walking, an artificial leg of an artificial limb using the artificial knee joint does not produce unexpected wobbles in the swing phase, and the artificial limb can provide enough support in the stance phase.

Abstract: An artificial knee has a supporting portion, a knee portion, and a leg portion. The knee portion has a saddle-like body, a front knee pivotally connected to the saddle-like body and a rear knee. The leg portion has a pneumatic cylinder received in the receiving space in the leg portion. Pivotal movement of the saddle-like body relative to the front knee is able to activate the pneumatic cylinder to provide a cushion effect to a load on top of the supporting portion.