Patent ID: 6106560
Filing Date: 2000-08-22
Classification: A61F,F16F

Abstract:
A patient-weight-activated hydraulic knee joint comprising a hydraulic shaft system comprising a cylinder having an upper chamber and a lower chamber divided by a partition, a piston disposed within each chamber and dividing each chamber into a lower section and an upper section, a piston rod joining the pistons and passing through the partition, a first hydraulic line connecting the upper section of the upper hydraulic chamber and the lower section of the lower hydraulic chamber, and a second hydraulic line connecting the lower section of the upper chamber and the upper section of the lower chamber, and further comprising a frame holding the hydraulic shaft system, a knee attachment pivotally mounted on the frame, a crank shaft disposed within the knee attachment and having a pivot axis, a pivot pin disposed within the knee attachment with an axis parallel to that of the crank shaft to which the piston rod is pivotally connected and thereby transmits hydraulic force, force transmission means are connected to the crank shaft which transmit the force of a patient's weight when brought to bear on the knee attachment, in which a hydraulic valve is situated in the second hydraulic line and controlled by the force transmission means and hydraulic pressure such that combined application of the patient's weight via the force transmission means and the hydraulic pressure to the valve stops the flow of hydraulic fluid.