Abstract: A prosthetic elbow includes a fixed member structure and a powered gearbox mechanism housed in a housing structure for rotating the forearm portion to varying angular positions. The powered gearbox mechanism includes a motor attached to the housing structure, a planetary frictional drive connected to a motor shaft of the motor and the housing structure, and a strain wave gear set having an input driven by the planetary fictional drive and an output attached to the fixed member structure, where the powered gearbox mechanism is configured to convert an output of the motor into a rotation of the housing structure relative to the fixed member structure, thereby causing the rotation of the forearm portion to varying angular positions relative to the upper arm. The fixed member structure and the housing structure each are connected to one of a forearm portion and an upper arm portion and rotatable relative to one another about an axis of rotation of the forearm portion.

Abstract: An adjustable counterbalance mechanism for a prosthetic elbow includes a torsional spring disposed in a housing structure coaxially to an axis of rotation of a forearm portion and a cord and pulley arrangement which includes a first pulley, a second pulley and a link member attached to a fixed member structure. The first pulley is attached to a second portion of the spring and connected to the second pulley by a first cord. The second pulley is pivotally attached to the housing structure and connected to the link member by a second cord. The cord and pulley arrangement is configured to transfer a moment of force due to spring force to the forearm portion to counteract the torque of a forearm due to gravity as the angle of the forearm portion changes relative to the upper arm portion.

Abstract: A prosthetic elbow includes a fixed member structure and a powered gearbox mechanism housed in a housing structure for rotating the forearm portion to varying angular positions. The powered gearbox mechanism includes a motor attached to the housing structure, a planetary frictional drive connected to a motor shaft of the motor and the housing structure, and a strain wave gear set having an input driven by the planetary fictional drive and an output attached to the fixed member structure, where the powered gearbox mechanism is configured to convert an output of the motor into a rotation of the housing structure relative to the fixed member structure, thereby causing the rotation of the forearm portion to varying angular positions relative to the upper arm. The fixed member structure and the housing structure each are connected to one of a forearm portion and an upper arm portion and rotatable relative to one another about an axis of rotation of the forearm portion.

Abstract: An adjustable counterbalance mechanism for a prosthetic elbow includes a torsional spring disposed in a housing structure coaxially to an axis of rotation of a forearm portion and a cord and pulley arrangement which includes a first pulley, a second pulley and a link member attached to a fixed member structure. The first pulley is attached to a second portion of the spring and connected to the second pulley by a first cord. The second pulley is pivotally attached to the housing structure and connected to the link member by a second cord. The cord and pulley arrangement is configured to transfer a moment of force due to spring force to the forearm portion to counteract the torque of a forearm due to gravity as the angle of the forearm portion changes relative to the upper arm portion.