GB574324A - Improvements in or relating to artificial arms - Google Patents

Abstract

574,324. Artificial limbs. BLATCHFORD, W. A. Oct. 1, 1943, No. 16116. [Class 81 (ii)] In an artificial arm having an elbow joint 3 and an appendage 10 adapted to move the forearm member 7 and also to actuate a gripping or hand appliance 23 by mechanism similar to that described in Specification 559,494, means are provided whereby the appliance normally held in its open position by spring means 26 is maintained in its gripping position without the wearer having to keep a pull on the appendage. A coiled spring 27 is mounted on a sleeve 9 fitted to the flexion arc 8 and is secured at one end to the arm 6 of the forearm member 7 and at the other end to a ratchet member 28 freely mounted on the sleeve. On rotation of the sleeve in one direction the coils of the spring bind on the sleeve and hold the plunger 13 in a depressed position and the jaws 24 in their gripping position. To release the locking, a lever 29 coacting with the ratchet member 28 is operated by hand or by an appendage to disengage the spring from the sleeve. On raising the lever 29 to a higher position, a spring-controlled pawl 32 engages with a tooth 34, thus holding the locking means out of action until a still further movement of the lever releases the pawl and allows the member 28 to return to its original position. The gripping member 23 may be rotatable in, and detachable from, the forearm and may be yieldably or positively locked therein, for example by the means described in Specification 550,886. The Provisional Specification refers to an alternative form of locking device in which the flexion arc is formed with rack teeth, or connected with a member having rack teeth, adapted to be engaged by a pawl on a spring-controlled pivoted lever member.