Patent GB-151372-A (GB)
Title: Improvements in or connected with artificial limbs
IPC: A61F2/58
Filed: 1919-06-24
Abstract: 151,372. Blatchford, C. D., and Blatchford, W. A. June 24, 1919. Limbs, artificial.-In the case of artificial limbs amputated near to the shoulder-joint or the hips, special means are provided for making the forward movement of the upper arm or the thigh member simultaneously bend the elbow-joint or knee-joint to raise the forearm or to straighten the lower leg. As applied to artificial arms, a bifurcated frame 11 is connected rigidly, either permanently or detachably, to the metal frame 6, the arms of which are attached to a short bucket or to a leather shoulder cap strapped to the body. An upper arm member 22 is secured detachably or permanently to a sector or quadrant 13 which is pivoted at 12 in the bifurcated frame to form the shoulder-joint. A cord 14, fixed to the periphery of the sector 13, is guided to a suitable point on the body so that the sector can be rotated anticlockwise to lift the upper arm. The forearm member 34 is connected detachably or permanently to a second sector 25 which is pivoted in the upper arm at 24 to form the elbow-joint. To bend the forearm simultaneously with the lifting of the upper arm, a cord 26, attached to the sector 25, passes through the upper arm to a fixed stop 28. As the upper arm is lifted the angle 12 of a triangle formed by joining the points 28, 12, 24 is continually increased, thus necessitating a corresponding increase in the opposite side 24, 28. The increase in this side causes the cord 26 to tighten and rotates the sector 25. A return cord may be fitted to restore the elbowjoint to its original position. Various locking- mechanisms are described, the shoulder-jomt being locked by a pivoted latch 16 engaging internal notches in the sector 13. The latch is raised to release the joint by a cord connected to suitable body harness and when desired may be held in inoperative position by the spring lever 21. The elbow-joint is locked by a bolt (not shown) engaging external notches in the sector 25. A pin 30, fixed to the bolt, co-operates with a bayonet slot 33 to hold the bolt inoperative when desired, and is connected to an operating cord 32 that is joined to the corresponding cord for the shoulder-joint for simultaneous unlocking of both joints. The forearm may be fitted at the lower end and also near the elbow-joint, and the upper arm above the shoulder-joint, with detachable connecting devices, as shown in Fig. 5, which can be adjusted to permit free axial rotation of the members or to lock them in an axially adjusted position. The spring pin 43 can be fixed in two axial positions corresponding to the engagement of the lug 44 with the interior and exterior of the socket casing. In one position the spigot member 36 is locked against rotation by the pin 46 engaging one of a series of holes 38, while in the other position it is unlocked, but retained in its socket by the member 40. A momentary greater displacement of the pin 43 releases the member 40 and frees the spigot. By removing one or more of the detachable sections of the limb, a tool or the like may be attached directly to the elbow or to the shoulder when convenient. In the case of artificial legs the mechamism comes into operation after the leg has been bent rearwardly by the taking of a step with the sound leg. The rotation of the sector 13 to move the thigh member forwardly operates through a cord similar to 26 to restore the rearwardly-bent knee-joint to the straight-line position.