DEMOUNTABLE JOINT

Abstract: A joint for demountably clamping a tubular member (32) into a socket defined by a main bore (40) without drilling or slitting the tube (32) has collets (44, 45) that fit into an auxiliary bore directed perpendicular to the axis of the main bore (40) and intersecting it over a small arc. The collets (44, 45) have part cylindrical faces (46) that conform to the curvature of tubular member (32) and press on it as a bolt (47) is tightened. Preferably a reinforcing insert is provided that fits into an end of the tubular member (32) and resists compressive load thereon.

Description: DEMOUNTABLE JOINT The present invention relates to a demountable joint by which a tube may be clamped to a socket. The invention provides a joint for demountably clamping a tubular member into a main bore defining a socket, characterised in that an auxiliary bore is directed perpendicular to the axis of the main bore and intersects it over a small arc, first and second collets each fit in the auxiliary bore and have at their inner ends part cylindrical bearing faces conforming to the curvature of a tubular member and clamping bolt means urge the first and second collets together so that they press on the tubular member and retain it in the socket. The demountable joint combines #manufacturing simplicity with ease of assembly and good fatigue life and has the particular advantage that the shin tube need not be weakened by drilling or slitting. An embodiment of the invention will now be illustrated in the accompanying drawings in which: Figure 1 is a view in vertical section of a demountable fastening for fixing the shin tube into the socket of the shin member in an artificial leg; and Figure 2 is a view of the joint in horizontal section on the line A-A of Figure 1. In Figures 1 and 2, the upper end of a shin pylon tube 32 is a push fit in a socket 40 defined by a vertical bore in the lower face of knee housing 30. A reinforcing insert 41 is a push fit in the top of tube 32. It is formed towards its lower end with a horizontally directed roinforcing annulus 42 which is capable of withstanding high compressive loads and at its top with an outwardly directed locating flange 43 which acts as an abutment for the top end of the tube 10. As more clearly seen in Figure 2 the socket 40 is formed with a horizontal bore that intersects the vertical bore in which tube 32 fits over a small arcuate portion thereof. A pair of collets 44, 45 fit into the horizontal bore, one of them 45 having a plain through-hole and the other 44 having a threaded through hole. Each collet has at its inner end a part cylindrical bearing surface 46 whose axis is normal to that of the collet and which conforms to the curvature of the outer surface of the tube 32 which can only be inserted fully home in the socket 40 when the bearing surfaces 46 are appropriately positioned. It will be noted that in the assembled joint the horizontal bore registers with the reinforcing annulus 42 of the insert 41. A clamping bolt 47 is inserted through collet 45 into coliet 44 in which it is threadedly located. As the bolt 47 is ti#S.-'. ened collets 44, 45 are urged together and their surfaces 46 press on the tube 32 to retain it in the socket EO.

Claims: CLAIMS: 1. A joint for demountably clamping a tubular member (32) into a main bore (40) defining a socket, characterised in that an auxiliary bore is directed perpendicular to the axis of the main bore (40) and intersects it over a small arc, first and second collets (44, 45) each fit in the auxiliary bore and have at their inner ends part cylindrical bearing faces (46) conforming to the curvature of a tubular member (32) and clamping bolt means (47) urge the first and second collets (44, 45) together so that they press on the tubular member (32) and retain it in the socket (40). 2. A joint according to claim 1, characterised in that the clamping bolt means (47) is passed through a smooth bore in one collet (45) and is engaged in a threaded bore in the other collet (44). 3. A joint according to claim 1 or 2, further comprising a reinforcing insert (41) in the end of the tubular member formed with a disc or annulus (42) which registers with the collets (44, 45) to resist compressive loads on the tube (32).

Inventors: MAY DENIS R W, MAY, DENIS RONALD WILLIAM
Applicants: J.E. HANGER & COMPANY LIMITED
Application year: 1982
Main classification: F16B2
IPC codes: A61F2, F16B2, F16B7