GB103610A - Improvements in Artificial Arms and Hands. - Google Patents

Abstract

103,610. Thomas, C. W. July 20, 1916. Limbs, artificial.-The fingers and thumb of an artificial hand are normally held distended by a spring, but may be closed to the gripping position by link-work mechanism operated through a cable by body harness. The fingers may be jointed only at the knuckles, or may have intermediate joints also, and the hand may be mounted so as to have a partial rotary movement when the arm is bent. In the form shown in Figs. 1 and 2, the four integral fingers 2 and the thumb 6 are moved about pivot pins 4, 7 by toggle-links 8, 10 and 9, 11 connected to a pin 12 working in a slotted plate 14 and connected to a cable 16, which passes over pulleys 17, 18 to shoulder harness. The spring 15 Fig. 5, each finger is independently mounted on a pivot pin 4 and comprises jointed sections 54, 55. The outer sections 54 are pivoted to links 57 formed with slots 58 engaging pins 59 on the inner segments 55 and connected to links 61 connected by cranks 63 to a shaft 64 adapted to be rocked by means of the cable 16. This construction normally holds the hand open. The hand is attached to the wrist portion of the artificial arm by a pin 20, which passes through a slotted plate 26 controlled by a spring 25 and adapted to engage a reduced neck 22 on the pin 20 so as to lock the hand in position. Automatic wrist-rotating mechanism operated on bending the arm comprises an arcuate rack 29 on the hand engaged by a toothed wheel or segment 30, which is partly rotated by a connecting-rod 34 actuated from a lug 35 on one of the upper arm members 36, Fig. 2a. The pin 31 on which the segment 30 oscillates may be moved in the slot 51, Fig. 2, so as to disengage the segment from the neck 29. The wrist may then be locked by a sliding bolt 52 engaging a recess 53 in the hand. The arm is held to the natural stump by a leather clasp 39 and padded straps 40. In a modified construction of the hand, causes the outer sections of the fingers to bend inwards relatively to the inner sections when the finger as a whole is pulled to the closed position. The thumb is actuated bv a link 67 attached to a short crank on the shaft 64, and the hand is normally held open by a spring 70. The hands are detachable from the arms and may be replaced by hooks such as those described in Specification 100,471. The hands may be made of wood or papier mÔchÚ, or, according to the Provisional Specification, of fibre. The Provisional Specification also describes a hand in which the wrist is locked by a pin which is caused to engage one of a series of holes in the wrist-plate by the action of axially displacing the toothed wheel. The locking-pin is held in place by a spring catch operable by a push-button on the wrist.