Abstract: A prosthetic knee joint includes a thigh connection part, a lower leg part coupled to the thigh connection part rotatably around an axis of a knee, an actuator coupled to the thigh connection part and the lower leg part, where the actuator is configured to restrict or assist movement of the thigh connection part, a detector unit for obtaining information about how the thigh connection part and the lower leg part are relatively positioned, a control unit for controlling driving of the actuator based on a result detected by the detector unit, and an estimating unit for estimating a state of the user's movement based on the result detected by the detector unit. When the estimating unit estimates that the user is not walking, the control unit sets a longer control cycle for the driving of the actuator than when the estimating unit estimates that the user is walking.

Abstract: This invention relates to a technique for hermetically sealing an artificial leg including a cylinder device. A rod member of the cylinder device extends from the inside to the outside of a shell structure of the cylinder device. The rod member is hermetically sealed at the periphery thereof by a bellows packing member. The bellows packing member comprises an inner bead, an outer bead which concentrically surrounds the outside of the inner bead, and a bellows packing body part which connects the inner and outer beads. The bellows packing body part includes corrugations, and each corrugation is less curved than an imaginary circle which is concentric with the inner bead and the outer bead. Both ends of each of the plurality of corrugations extend to the outer bead or are located at positions closer to the outer bead than the inner bead.

Abstract: A prosthetic knee joint includes a knee portion coupled to the socket, a cylinder that is coupled to the knee portion and limits or aids operation of the knee portion, a knee angle sensor that directly or indirectly detects a knee angle value, and a control unit that controls driving of the cylinder. The control unit may calculate a knee angular velocity value based on the knee angle value detected by the knee angle sensor. The control unit determines whether the knee portion is in a knee still state based on the knee angular velocity value and automatically restricts contraction of the cylinder based on a time duration in which the knee portion is in the knee still state.

Abstract: This invention relates to a technique for hermetically sealing an artificial leg including a cylinder device. A shell structure surrounds the outside of the cylinder device. The cylinder device is not entirely received within the shell structure, but a rod member extends to the outside of the shell structure from the cylinder body within the shell structure and a part of the rod member is located outside the shell structure. In this invention, the rod member, which extends from the inside to the outside of the shell structure, is hermetically sealed at the periphery thereof by a bellows packing member. The bellows packing member comprises an inner bead, an outer bead which concentrically surrounds the outside of the inner bead, and a bellows packing body part which connects the inner and outer beads.