Patent GB-1460752-A (GB)
Title: Method and apparatus for jointing two elements of metal or thrmoplastics by friction welding
IPC: B29C65/00
Filed: 1974-02-20
Abstract: 1460752 Seaming non-metallic sheet material NAPHTACHIMIE SA 20 Feb 1974 [21 Feb 1973] 6212/76 Divided out of 1460667 Heading B5K [Also in Division B3] In friction welding two elements of thermoplastics material an axially fixed intermediate member is rotated or oscillated between the elements while exerting a force on each element to hold the elements in contact with the member, the force exerted being controlled by an apparatus responsive to differences in temperature and/or solftening of the metal of the two pairs of contacting surfaces. In an embodiment an apparatus for friction welding two tubes 10, 11 of thermoplastics material by means of an intermediate sleeve 12 comprises a framework formed by two bifurcated end members 16, 16a, Fig. 1, carrying retractable feet and connected by ties or crossbars 1, 17 with plates 2, 2a and 6, 6a fixed to the ties 1. The tubes 10, 11 pass through the members 2, 2a, 16 and 16a and plates 3, 3a carrying ram operated clamping members for clamping the tubes 10, 11 are slidable on the ties 1 under the action of rams 15, 15a. The sleeve 12 is arranged within a two part tubular member 4, 4a which has hydraulic clamping means 5, 5a for securing the member 4, 4a to the sleeve. The member 4, 4a is secured to an annular pinion 8 driven by means of a motor 9 and thrust bearings 7, 7a are provided between the member 4, 4a and the two plates 6, 6a fixed to the cross-bars 1. In operation the sleeve is rotated and the tubes 10, 12 are thrust towards it by means of the rams 15, 15a and if one joint condition is ahead of that of the other, as detected e.g. by a pyrometer, the pressure applied to the tube on that side is reduced or ceased and then both joints have reached the same condition the joints are forged by exerting equal forces by the rams 15, 15a after stopping the rotation of the sleeve. In a modification the rams 15, 15a are arranged to pull the tubes together, being mounted closer to the member 4, 4a and giving a shorter machine and in another modification the pistons for the rams are carried on the ends of the cross-bars 1. The apparatus can be arranged in two halves which can be opened to permit mounting the apparatus on large tubes, each half unit being secured to a member 21, Fig. 6. The two members 21 are opened and closed by rams 25 acting through linkage 22, 23 and the pinion 8 is rotated by two electric or hydraulic motors. Instead of direct pinion drive a notched belt may be used. The bearing 7, 7a are each formed as two half bearings to allow movement apart or rollers displaceable within arcuate slots in the plates 6, 6a may be used. The apparatus when of the non opening kind may have provision for receiving curved pipes and the devices for gripping the sleeve within the members 4, 4a may include wedging members. A unit for removing the internal weld burrs on the welded assembly comprises a shaft 60, Fig. 20 with circular milling cutters 61, 61a and a brush 62, the shaft being driven by a motor 65 slidable in a clamp 67 for gripping the inside of one of the welded tubes.