Patent ID: 8690963

Claim:
A hand prosthesis comprising: a chassis; and at least one joint adapted to provide for flexion and extension movement of the chassis from a neutral position in relation to the coupling elements, the joint including first and second spring elements having progressive spring characteristics that urge the chassis from an angle of flexion or extension toward the neutral position, wherein the first and second spring elements are elastomer parts; wherein the chassis is mounted to be rotatable about a rotation axis that is arranged at a right angle to an axis of flexion and extension movement and configured to be parallel to a longitudinal axis of a residual portion of an arm to which the hand prosthesis is mounted; wherein the neutral position is aligned at an obtuse angle in relation to an angle that is at a right angle to the rotation axis of flexion and extension movement; a locking device adapted to lock the joint to prevent flexion or extension movement of the chassis, the locking device being actuated in a direction along the rotation axis from a locked position that limits at least one of flexion movement and extension movement of the chassis to a released position that permits at least one of flexion movement or extension movement of the chassis.