Nabtesco Corporation

Nabco Limited

Aritomo Fukui

Yoshiaki Nakaya

Masahiko Okuda

Toyohiko Imakita

There is provided a prosthetic limb having a flexible knee brake function, which is designed such that it can be mechanically detected which part of the foot the load of the wearer is imposed on. In a thigh prosthetic limb (), a joint upper member () including a knee plate () and a joint lower member () including a base bracket () integral with the frame () are operated to bend the knee. In the housing member (), there are provided not only a knee axis but also a hydraulic brake circuit. There is a link mechanism () which allows a small relative motion between the housing member () and the base bracket () on the main body part side. The link mechanism () has an instantaneous center between the toe and the heel part of the prosthetic limb. This instantaneous center serves as a sensing point and detects which part of the foot the load of the wearer is imposed on by distinguishing a first case in which the wearer's load is imposed on the heel and a second case in which the wearer's load is imposed on the toe. Based on the detection result made by the link mechanism (), the hydraulic brake circuit is controlled so that a flexible knee braking operation can be made.

Prosthetic leg with knee braking function

A selector valve capable of maintaining a closed position for a while even if an operating force to a valve element () is eliminated when the selector valve () is switched from a closed position (braking state) to an open position. The valve element () of the selector valve () receives an operating force from the outside and a returning force in the opposite direction of the operating force by a valve spring (). Accordingly, the valve element () opens and closes the valve by making the first end () of the valve element () seat on/unseat from a valve seat () on the housing () side according to the presence or absence of the operating force. A first port () and a second port () on both sides of the valve seat () are connected or cut off from each other by the opening and closing. The valve element () is formed in a stepped structure, and receives a force based on a difference in pressure receiving area by the stepped structure which results from the pressure of hydraulic fluid. The force can maintain the closed position of the valve for a while.

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Kobe, Japan

Aritomo Fukui