GB238665A - Improvements in artificial limbs - Google Patents

Abstract

238,665. Marks, E. C. R., (Livingston Artificial Limb Co.). July 7, 1924. Limbs, artificial.- An artificial hand is provided with jointed fingers and thumb which are opened and closed by rigid members connecting them to a drum rotatable about an axis perpendicular to the plane of the hand. The drum is rotated in one direction by a spring enclosed in the drum, locking means being provided to hold the fingers in any position. Means for rotating the wrist and bend. ing and locking the arm are also provided. Finger and thumb operating mechanism. Each of the fingers comprises three pivoted sections connected by links, the inner section being provided with a toothed segment 49 which engages a toothed segment 48 mounted on a shaft 50. The shaft 50 has a crank connected by a link to a pin on a drum 60 which can be rotated in one direction by a line 67 and in opposite direction by an enclosed spring 81. The drum and fingers can be held in any position by a detent 74 which engages teeth on the drum but can be released therefrom by a line 76. The thumb is operated by links 84, 86 pivoted to the thumb and to a pin on the drum 60. The fingers and thumb are provided with elastic tips. Wrist rotating mechanism. The wrist is connected to the forearm by a ball-bearing joint 9, a spring 14 holding the wrist normally in one extreme position. The wrist is rotated by a line 21 fastened to the hand at 22 and passing over pulleys 17, 18, 19, a stop being provided to limit the rotation to a quarter turn. Arm bending and locking mechanism. A pull on the line 21 first rotates the hand and then bends the arm. The arm is locked in any position by a pawl 29 which engages teeth on a sector 25 fixed to the forearm. The pawl is released by raising the arm to its extreme position whereupon the pawl 29 engages a cam surface. 28 on the sector causing the pawl to return, when the arm is lowered, along a plain curved face 27 on the sector. Fig. 1 shows the harness to which the various operating lines are attached. The drum operating line 67 passes over a pulley 71 and round the opposite arm of the wearer where it is attached to a strap 66. The line 67 is pulled by an outward movement of the arm. The detent releasing line 76 passes over a pulley 78, under a pulley 79, and over the shoulder as shown at 80, where it is connected to the strap 66. The line 76 is pulled by raising the shoulder. The arm-bending and wrist-rotating line 21 passes over the wearer's shoulder and is connected at 22<a> to a belt 15. An upward movement of the shoulder produces a pull on the line 21.