GB138528A - Improvements in or relating to artificial legs - Google Patents

Abstract

138,528. Clack, C. F. May 22, 1919. Limbs, artificial.-A knee-joint pivot-pin is designed to serve as an operating-means for the calf member, as a kneecheck, and as a means for locking thigh and calf members in the straight-line position, the arrangement of parts being such that the calf member is devoid of any of the actuating-mechanism. In the construction shown in Figs. 2 and 4, the pivot pin d is supported in a pair of spaced bearings c depending from the knee-ball a. Two pairs of parallel crank-arms i, fixed on or formed integral with the pivot pin between the bearings, support pulleys for receiving the usual operating-cords k. A central projection l on the pivot pin abuts against a pad m in the straight-line position of the members and acts as a knee-check. When the weight of the wearer comes on the limb in the straightline position, the stump depresses a spring pin p which enters a hole in the projection l and locks the joint. A detachbale knee-cap is provided with lugs through which securing-screws are passed into the outer surface of the thigh member. The calf member is fixed to the pivot pin so as to turn therewith. One method of fixing is shown in Fig. 5, where the pin is internally threaded at its ends and is formed with lugs d<2>. The lugs pass into recesses on the calf member, and bolts g connect the calf member to the pin. The heads of the bolts are secured against rotation by grub-screws h. In the modified arrangement shown in Fig. 6, the pivot pin has squared or flattened ends, and a cap e<3> is used to secure it to the calf member e. A pin e<4> prevents axial displacement of the pivot pin.