Nabco Limited

Norio Shiraishi

Masahiko Okuda

Yasukazu Furuichi

Kazuo Nakatani

Yoshiaki Nakaya

Kotaro Tanaka

Kiyoshi Morimoto

Tsutomu Togashi

There is provided an air-cylinder apparatus for use in a prosthetic limb capable of effectively adjusting the pressure characteristics over a wide range of walking speed. A second chamber defined by a piston is increased in pressure by air confined therein in accordance with the bending motion of the knee. Air is restricted from flowing out of the second chamber by a constant throttle valve In addition, the second chamber is divided into plural chambers in accordance with increase in bending angle of the knee and air is restricted from flowing out of the newly divided chambers by throttle valves corresponding thereto. The division of the second chamber is achieved by mutual engagement between a projection on the piston side and a recess on the bottom part of a cylinder body.

Air-cylinder apparatus for prosthetic limb

There is provided a prosthetic leg with an extension auxiliary mechanism 1100 capable of generating an extension torque only when an angle of bending of the knee is small. A knee joint 80 of a thigh prosthesis 170 is of a multi-axis structure, and a front and a rear link 130, 150 together with an upper thigh member 110 and a lower thigh member 120 constitutes a constrained chain. An extension auxiliary mechanism 1100 having a compression spring is supported between the lower thigh member 120 and the rear link 150. An extension torque generated by the extension auxiliary mechanism 1100 is determined by a product of a force caused by biasing of the compression spring and a distance from a line of action of the force to the center of rotation of the rear link 150. Here, at a stage where the bending angle of the knee exceeds, for example, 15 degrees, an axis of the compression spring is brought generally into alignment with a connecting portion 170O between the rear link 150 and the lower thigh member 120. By doing so, the distance related to the extension torque becomes approximately zero and the extension torque itself becomes approximately zero.

Prosthetic leg with extension auxiliary mechanism

Paying attention to the mechanical play between the first and second support members for supporting opposite end portions of a knee axis and a brake block located between the support members, the present invention chiefly aims at removing the play in the direction of an axis of the knee axis in an effective and a reliable manner. In order to achieve this object, according to the present invention, a plurality of spacer members are inserted between each support member and the brake block such that the spacer members may slide on the mutual abutment surface. Each spacer member is of a ring type. The spacer members are fitted to and supported by the knee axis in a state that the spacer members are overlaid one upon another in the axial direction of the knee axis. In order to enhance the smooth sliding on the abutment surface, the spacer members are preferably made of resin material. In order to enhance the smoother sliding, at least one spacer member having the abutment surface is more preferably made of resin of low friction, such as oil-contained resin or phenol resin. The remaining spacer member contacting the resin of low friction may be made of such resin as polyacetal, polyamide and tetraethylene fluoride. Most preferably, one spacer member is made of oil-contained polyacetal resin which is especially excellent in low friction, and the remaining spacer contacting the first-mentioned spacer member is made of non-oil contained polyacetal resin.

Artificial limb including knee joint

An artificial limb provides for positional relation between a first pin for rotatably connecting one end of an air cylinder device to a lower member and a second pin for rotatably connecting the other end of the air cylinder device to an upper member. The attaching position of the second pin is set to satisfy certain predetermined conditions when an artificial limb is in a completely extended state. The position of an air cylinder device (particularly, the attaching position of the second pin) is changed in conformity with a walking speed which is variable in phase such as normal walking, quick walking, and running with small steps. The artificial limb further comprises a pin position change capable of changing the position of a second pin rotatably connected to an upper member in conformity with variation of walking speed. A first example of the pin position change includes a plurality of attachment holes formed on the knee plate of the upper member and the position of the second pin is changed by attaching the second pin selectively to one of the attachment holes. If it is designed such that an elongate hole is formed along a circular arc so that the attaching position to the elongate hole can be changed, the position of the second pin can be changed steplessly or successively.

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Kobe, Japan

Norio Shiraishi