Nabtesco Corporation

Nabco Limited

Masahiko Okuda

Hiroaki Hashimoto

Yoshiaki Nakaya

Norio Shiraishi

Yasukazu Furuichi

Toyohiko Imakita

Takuya Shirata

Yoshinori Takezawa

Aritomo Fukui

Kazuo Nakatani

Shinpei Matsuo

Tsutomu Togashi

Kotaro Tanaka

Kiyoshi Morimoto

Yoshihiro Kodama

Yoshiko Fujieda

Shuji Fujisawa

A multi-articulated link knee joint includes: a knee unit in which an upper link unit rotates relative to a lower link unit by a multi-articulated link mechanism including a plurality of link units including the upper link unit and the lower link unit; a relative position detector for detecting a relative position of the upper link unit relative to the lower link unit; and an angle detector for obtaining a bending angle of the knee unit from the detected relative position.

Multi-articulated link knee joint

A prosthetic leg knee joint includes a thigh connection part that is provided on the thigh side, a lower leg part that is provided rotatably around a knee shaft connected to the thigh connection part, a four-bar link mechanism that sets an instant center S whose relative position with respect to the thigh connection part is substantially constant regardless of the relative position between the thigh connection part and the lower leg part, and a braking unit that brakes the movement of the lower leg part in accordance with the relative position between the instance center S set by the four-bar link mechanism and the lower leg part.

Prosthetic leg knee joint, braking device, and load position detector

A multi-articulated link knee joint includes: a knee unit in which an upper link unit rotates relative to a lower link unit by a multi-articulated link mechanism including a plurality of link units including the upper link unit and the lower link unit; a cylinder device for assisting the motion of the knee unit and moving in accordance with the rotation of the upper link unit; a position detector for detecting the distance from the lower link unit to the cylinder device; and an angle detector for obtaining the bending angle of the knee unit from the detected distance from the cylinder device.

A multi-articulated link knee joint includes: a knee unit in which an upper link member is structured to rotate relative to a lower link member by a multi-articulated link mechanism including a plurality of link members including the upper link member and the lower link member; a driven member to move in accordance with the rotation of the upper link member; a position detector for detecting the position of the driven member, the position detector provided at the lower link member; and an angle detector for obtaining the bending angle of the knee unit from the position of the driven member.

A multi-articulated link knee joint capable of detecting a bending angle of a knee section without causing problems of an installation space and wiring of a sensor is provided. A four-link knee joint includes a knee section of a four-link mechanism, a fluid cylinder that restrains an action of the knee section, a position detecting device that detects a position of a piston rod with respect to a cylinder tube as an extension and contraction amount of the cylinder, and a computer that acquires a bending angle of the knee section by converting the position detected by the position detecting device.

A technology for making the sensation at use of prosthetic limbs utilizing a hydraulic cylinder and a spring cylinder as comfortable as at use of those utilizing a pneumatic cylinder and further for improving walk following properties. In particular, the arrangement of a hydraulic cylinder or a spring cylinder, or the like, is specified. Accordingly, the resistance produced by the hydraulic cylinder or spring cylinder in accordance with an increase of knee angle is increased, The first torque T1 at the first stage of initial period of bend of the knee joint is made small, while the second torque T2 at the second stage of final period of the further advanced bend of knee joint is made large, thereby satisfying a relation of T1&#x2267;T2, as different from conventional ones.

Prosthetic limbs with means capable of reducing torque in the initial period of bend of knee joint

The disclosure relates to a technology of a manual lock mechanism for manually switching over the oscillating motion of an upper member and a lower member at a knee joint between a locked condition and an unlocked condition. More particularly, the disclosure aims at a simple structure of the manual lock mechanism and a size reduction of the knee joint or an artificial leg including the manual lock mechanism. For these purposes, one of oscillating shafts for swingingly coupling the upper and lower members is regulated. Therefore, the manual lock mechanism includes an oscillating shaft including an irregular part and a lock member for regulating the movement of the oscillating shaft. The lock member can be switched over between a locked condition where the lock member is in contact with the irregular part of the oscillating shaft and the unlocked condition where it is separate from the irregular part. When the lock member is in the locked condition, force from the oscillating shaft is applied as compression load in the longitudinal direction of the lock member.

Knee joint including manual lock mechanism and artificial thigh

Adjustable adaptor for a prosthetic leg

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.

Closed position maintainable selector valve, knee torque device using the valve, and artificial leg

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

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.

Growing community of inventors

Kobe, Japan

Masahiko Okuda