GB422508A - Improved construction of wrist joint for artificial arms - Google Patents

Abstract

422,508. Wrist-joint for artificial arms. REEVE, H. J., 147, Galpins Road, Thornton Heath, CLEAVER, C. H., 112, Upper Richmond Road, East Sheen, and STEEPER, H., 59, Westbury Road, New Maldon, all in Surrey. Dec. 30, 1933, No. 36705. [Class 81 (ii)] Relates to a wrist joint of the kind wherein a plate or the hand or tool-carrier has a central grooved stem and a surrounding ring of holes, the stem being inserted in a tubular extension of a plate secured to the forearm and held therein by a spring-controlled catch riding in a slot and engaging the groove in the stem, the hand or tool-carrier being revolvable and held in any adjusted position by spring- controlled balls or plungers engaging the holes in its plate, the whole capable of being locked by a separate device, such as is described in Specification 385,079. The grooved stem 3 of the hand 2 enters a tube 8, Figs. 1 and 10, secured within an extension 6 of the forearm plate 5. A disc 9 on this plate is formed with one or more holes 10, Fig. 4, through which project spring-pressed balls 14, and a hole 11 housing a spring-pressed locking bolt 17, Fig. 8, having a projecting arm 17<a> which is actuated by a crank or cam 19 on a shaft 20 provided with an arm or turnbutton 21 projecting beyond the forearm. The holes 10, 11 coincide with the holes 4 in the hand plate, Fig. 1. A catch 22, Fig. 10, slides on the end of the extension 6 and is formed with a central aperture which engages the groove in the stem 3 of the hand through a slot 8<a> in the tube 8. The catch can be slid downward against the action of a spring 25 and freed by pressure on a stem 26. A flanged ring 30 surrounds the tube 8 and is urged by a spring 31 so as normally to project beyond the disc 9.