Patent ID: 8388558

Claim:
A walking assistance device, comprising: a load transmit assembly which transfers a load for supporting a part of the weight of a user to the body trunk of the user; a foot-worn assembly to be attached to a foot of the user; a leg link which connects the foot-worn assembly to the load transmit assembly, the leg link comprising an upper link member extended from the load transmit assembly via a first joint, a lower link member extended from the foot-worn assembly via a second joint, and a third joint which bendably connects the upper link member and the lower link member; and a drive mechanism for driving the third joint, wherein the drive mechanism has a linear-motion actuator including an electric motor mounted on the upper link member, a nut member which is rotationally driven by the electric motor and disposed in an enclosure swingably supported by the upper link member, and a linear-motion output shaft having a thread groove formed in an outer peripheral surface thereof, the thread groove screwing with the nut member through the intermediary of a ball retained in the nut member, and a crank arm which is secured to the lower link member coaxially with a joint axis of the third joint and swingably attached to one end of the linear-motion output shaft, and the drive mechanism is constructed such that a translational force output from the linear-motion output shaft of the linear-motion actuator is converted into a rotational driving force of the third joint through the crank arm.