GB127599A - Improvements in or relating to Artificial Hands. - Google Patents

Abstract

127,599. Despinasse, J. June 7, 1917, [Convention date]. Limbs, artificial.-Comprises means for bending 3-joint fingers so that they can co-operate with the main inner surface of a thumb to hold the large objects such as the handles of tools, or cooperate with the tip of the thumb to hold thin objects such as sheets of paper. The four fingers are connected in pairs by cords 12 to a sliding plate 13, and the plate is moved towards the wrist to bend the fingers, by a cord 15 attached to a pulley 20 which is disconnectably coupled to a second pulley 19 actuated by the harness cord 19<a>. The ends of the cords 12 are fixed to the outermost phalanges of adjacent fingers and are passed round pulleys 14 on the plate 13 in addition to being passed once round pulleys 10, 11 at the intermediate and bottom joints of each finger. Cords 16, connecting the outermost phalanges of the fingers to springs 17, maintain the fingers normally in the open position. The initial pull on the cord 19<a> automatically couples the pulleys 19, 20 by rotating the pulley 19 against the action of the interior spring 34 until a lateral hole registers with and is engaged by a double-spring sliding bolt 30, thus locking the pulleys together. A further pull on the cord then rotates the pulley 20 to bend the fingers to any desired extent. A pawl and ratchet gear maintains the fingers at any desired angle of bending. When the bent fingers are locked, the next step is to uncouple the pulleys 19, 20 automatically by releasing the strain on the cord 19<a>. The rotation of the pulley 20 moves the spring bolt out of line with the inwardly-acting spring 32 on the casing, leaving it jammed in the pulley 19 by the driving- force between the two pulleys. When the tension on the end 19<a> is released, the outwardly-acting spring 33 withdraws the bolt. The release of the fingers may be effected in two ways :-(1) by applying another pull on the cord 19<a> and rotating the uncoupled pulley 19 until a projection 35 thereon raises a tail-piece on the pawl 25, or (2) by operating the lever 38 which raises the pawl through a suitable linkage. When the pawl is raised, the springs 17 open the hand until a long tooth 24 on the ratchet-wheel abuts against the raised pawl. This long tooth determines the limit of the opening movement of the hand. The thumb, which is pivoted to the hand, can be moved into any selected position and then retained therein by a suitably-operated catch entering into notches at the base of the joint. In the Specification as open to inspection under Sect. 91 (3) (a), a spring-mounted thumb is described, the thumb being pressed against its seating by a spring-influenced rod 40, Fig. 4 (Cancelled), with sufficient force to retain it at any angle at which it was set to co-operate with the fingers in the gripping action. This subjectmatter does not appear in the Specification as accepted.