GB716550A - Improvements in artificial limbs - Google Patents

Abstract

716,550. Artificial limbs. STEEPER, (ROEHAMPTON), Ltd., H. April 30, 1952 [May 1, 1951], No. 10185/51. Class 81(2) A joint for an artificial limb includes two co-operating parts, one part comprising a housing formed with a bearing surface, locking means and mechanism within the housing for actuating the' locking means and the second part being mounted on the bearing surface and shaped for engagement by the locking means so that the wearer can actuate the locking means for permitting or preventing angular movement of one part relative to the other. An artificial arm consists of an upper arm portion 1, Fig: 1, connected to a fore-arm portion 2 by pairs of steels 3, 4, 5, 6 pivoted together at the elbow joint. At least one pair of steels is provided with locking mechanism for holding the forearm 2 in any desired position relative to the upper arm 1. One steel 3 is provided with a ring 11, Fig. 4, having diametrically opposed recesses 12, which is mounted on a bearing portion 10 of a housing 7 forming a head of the other steel 4 of the pair. Two recesses 13 containing plungers 14 are provided in the housing 7 which, when the arm is bent, correspond with one pair of the recesses' 12 in the ring 11. A disc 18, Figs. 7 and 12, is seated in the inner portion of the housing 7 and is able to be rotated against a helical spring 24 one end of which is secured to a boss 25, Fig. 9, on a tension adjusting plate 26 and the other end of which is secured to the disc 18. A chain 19 secured to the wearer's control cord 23 is also attached to the disc 18. The position of the tension adjusting plate 26 is determned by the engagement of one of several apertures 27 with a projection 28 on a plate 9, Fig. 7, which closes the joint on the inner side. In operation the arm is bent to the desired position and the chain 19 is pulled by the wearer. This rotates the disc 18 against the spring 24. A pawl 29, carried by the disc 18 is spring-pressed against a ratchet 30 which then rotates with the disc 18. The ratchet wheel is provided with depressed cam surfaces 32 against which projections on plungers 14 are pressed. On rotation of the ratchet wheel the plungers 14 are pressed outwardly by a spring 15 so that they engage one of the pairs of recesses 12 in the ring 11 and so lock the arm in the desired position. When it is desired that the position of the arm should be changed, the chain 19 is again pulled to rotate the disc 18 and ratchet wheel so that the cam surfaces 32 cause the plungers 14 to be withdrawn from the recesses 12 and the position of the arm may be altered. The invention may be applied to knee joints or to surgical appliances for the support of limbs.