Patent GB-720512-A (GB)
Title: Improvements in ankle and knee supports for personal wear and for artificial limbs
IPC: A61F5/01
Filed: 1952-07-22
Abstract: 720,512. Limb supports. GUEST, J. July 21, 1953 [July 22, 1952 ; Jan. 17, 1953], Nos. 18452/52 and 1422/53. Class 81 (2). An ankle or knee support is provided with a pair of rigid splint members respectively attached to the limb above and below the joint concerned, a pivot pin connecting adjacent ends of such members and having an axis aligned with or parallel to the main axis of flexure of the joint and an enclosed coil spring arranged adjacent the pivot pin for torsionally loading the joint. In a support for a weak ankle or the ankle joint of an artificial limb, a splint 10 is fixed to the leg below the knee by a C-shaped band 12 provided with a strap 13 and buckle 14. The lower end of the splint 10 is rigidly secured to a light alloy casting 19 having a slot 21 in its lower portion for the reception of the upper part of a second splint 11 which is mounted on a pivot bolt or screw 20 extending across the slot 21. The lower part of the second splint 11 is fixed to the heel of a boot or shoe. The slot 21 in the casting 19 is continuous with a cylindrical cavity 22 in which is housed a coil spring 24 compressed between an adjustable grub screw 25 and an extension 26 of the second splint 11. A steel ball 27 may be interposed between the spring 24 and the extension 26, The coil spring 24 thus is able to urge a dropped foot into its normal flexed position. Alternatively, the casting 19 may be mounted the other way round, an adjustable grub screw being threaded in a second cylindrical cavity 23 which is inclined to the first cylindrical cavity 22. The pivot bolt 20 may be offset from the centre line of the upper splint 10 on the side remote from the grub screw. Several alternative holes 28 may be provided for the pivot bolt 20 to enable the offsetting to be varied as desired. The upper splint member 10 may be secured to the limb by a gaiter-like casing (not shown) having a back portion shaped if required to resemble a natural calf and made of rigid material e.g. fibrous material impregnated or coated with plastic material such as nitrocellulose, benzene, acetone, creosote or castor oil, a thermosetting resin material or stiff leather. The front portion is of softer material, e.g. polyvinyl chloride, textile or leather and is provided with fastening means, e.g. lacing. The construction shown in Figs. 1 and 2 may be applied to a knee joint (not shown) in which case the splint members are secured above and below the knee by bands similar to the band 12. In an alternative construction of joint (Fig. 4) the adjacent ends of the splints 10, 11 are formed with circular enlargements 30, 33 concentric with a pivot bolt 29. One enlargement 30 of the upper splint 10 has a hollow cylindrical spigot 31 journalled in a socket 32 of the other enlargement 33 of the splint 11, the pivot 29 being fixed in the base of the socket 32. A spiral spring 35 wound round the pivot 29 has one end secured to the pivot 29 by a peg 38 and the other end secured to the spigot 31. The spring 35 is loaded as desired by relative rotation of the splints 10, 11 during assembly of the device.