Myoelectrically controlled knee joint locking device

• US 5,062,857 A
• Filed: 06/05/1990
• Issued: 11/05/1991
• Est. Priority Date: 06/05/1990
• Status: Expired due to Term

• Current Assignee: Advanced Prosthestetics Development Corporation
• Original Assignee: Advanced Prosthestetics Development Corporation
• Inventors: Sulima, Edward J. Jr., Berringer, WIlliam A.
• Primary Examiner(s): Green, Randall L.
• Assistant Examiner(s): Willse, David H.
• Application Number:
  US07/533,430
• Time in Patent Office: 518 Days
• Field of Search: 623/24, 623/25, 623/39, 623/43, 623/44, 92/85 R
• US Class Current: 623/25
• CPC Class Codes: A61F 2/64 Knee joints
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2/748 Valve systems
• CPC Class Codes: A61F 2002/6854 for locking or unlocking a joint

Abstract

A damped knee joint may be locked myoelectrically at any angle of flexing. A special hydraulic cylinder is pivoted above the knee center at one end and in the shank at the other end. This attachment strategy allows 110 degrees of knee flexion, permitting the normal range of sitting and standing positions. The cylinder assembly incorporates a closed loop, sealed hydraulic system and electro-mechanical valving to control piston position. The closed loop hydraulic system also prevents fluid leakage and contamination. Valving is accomplished by a microelectrically operated barrel or gate valve located in a hydraulic system. The use of a barrel or gate valve allows the microelectrically operated plunger to be physically isolated from the working fluid and to be operated reliably at the highest working pressure of the systems.

Claims

1. A myoelectrically controlled knee joint locking device, said device comprising:

an upper artificial limb,

a lower artificial limb pivotably mounted on said upper artificial limb for free-swinging extension and retraction of said lower artificial limb with respect to said upper artificial limb,

a hydraulic piston cylinder assembly, a piston rod of said assembly being pivotably mounted on said upper artificial limb, a cylinder of said assembly being pivotably mounted on said lower artificial limb,

a piston mounted on said piston rod being slidably mounted in said cylinder,

hydraulic fluid being in sealed communication with opposite sides of said piston for movement of said piston in two opposite directions and transfer of said fluid to opposite sides of said piston,

retraction adjustment means for regulating flow of said hydraulic fluid and therefore the speed of retraction of said lower artificial limb when said piston is moved in one of the two opposite directions by movement of said lower artificial limb with respect to said upper artificial limb,

extension adjustment means for regulating flow of said hydraulic fluid therefore the speed of extension of said lower artificial limb when said piston is moved in the other of the two opposite directions by movement of said lower artificial limb with respect to said upper artificial limb,

a single sensing means mounted on a single muscle of the user for generating a single signal in response to a detected myoelectric potential generated voluntarily or involuntarily by the muscle of the user in response to a desired instantaneous locking of said hydraulic piston cylinder assembly against retraction of said lower artificial limb, and

control means responsive to said signal for controlling said assembly to permit only extension of said artificial limb with respect to said upper artificial limb and to instantaneously lock said assembly against retraction of said lower artificial limb at any point along a path of travel of said piston rod.

2. A myoelectrically controlled knee joint locking device as claimed in claim 1, wherein said control means includes a solenoid actuated in response to said signal to block a fluid flow path in one direction to prevent retraction of said lower artificial limb with respect to said upper artificial limb.

3. A myoelectrically controlled knee joint locking device as claimed in claim 2, wherein said solenoid includes a spool inserted into the fluid flow path upon actuation of the solenoid.

4. A myoelectrically controlled knee joint locking device as claimed in claim 1, wherein said extension adjustment means is separate from said retraction adjustment means.

5. A myoelectrically controlled knee joint as claimed in claim 1, wherein said pivot means includes a sponge accumulator for smooth extension and retraction of said lower artificial limb with respect to said upper artificial limb.

6. A myoelectrically controlled knee joint locking device as claimed in claim 1, wherein a sponge accumulator is located in said hydraulic piston cylinder assembly and surrounds said piston rod.