Patent GB-1390821-A (GB)
Title: Inertial friction welding machines
IPC: B23K20/12
Filed: 1972-03-28
Abstract: 1390821 Welding by pressure BRITISH RAILWAYS BOARD 19 March 1973 [28 March 1972] 14482/72 Heading B3R [Also in Division F2] An inertial friction welding machine for welding two pieces, e.g. an aluminium stud and a steel rail, comprises a flywheel 2, means 32 to rotate the flywheel, a two-part rotatable body 11 having slip clutch means 14 between the two parts, one part 19 being operatively connected to the flywheel to allow the rotatable body to be rotated by the flywheel and the other part carrying a chuck 12 for one of the pieces 13, and further means 24 adapted to be connected to the flywheel to cause axial movement of the rotatable body 11 when the body is rotated by the flywheel to generate an axial load between the pieces to be welded, the slip clutch means 14 being arranged to slip in response to a predetermined torque generated by the axial load to provide relative rotation between the two parts of the rotatable body 11, the further means 24 being such that when the relative rotation takes place the residual energy of the flywheel is adapted to generate an axial forging load between the pieces being bonded. The flywheel 2 is secured to a shaft 3 carrying two gears 4, 5, the gear 4 having 31 teeth and meshing with gear 6 having 29 teeth secured to a shaft 7 and the gear 5 having 30 teeth and meshing with a gear 10 also having 30 teeth mounted on the rotatable body 11. The body part 19 carries the chuck 12 and is connected to the body part 20 by the slip clutch having balls 17 located in a recess between flanges 15, 16 with a spring 18 retaining the balls in normal position until the torque is such that the balls roll circumferentially to new deeper positions to allow the clutch to slip. The flange 15 forms part of the chuck housing 19 and the flange 16 forms part of a tubular member 20 to which the gear 10 is secured. An internally screw threaded member 21 is located in a bore 22 in the housing 19 to rotate with the housing but to be axially slidable therein and a screw threaded member 24 is threaded in the member 21 and connected to a centrifugal clutch 25. The clutch 25 causes the member 24 to move to the right so that teeth 27 on the member 24 engage teeth 28 on the shaft 7. A rod 29 carried by the member 24 extends through the shaft 7 to trip a drive gear brake. The drive gear for the flywheel is hand driven by a crank 31 and comprises two pairs of wheels 33, 34, the wheels of each pair being coupled together by a steel tape 35 which provides a drive ration which changes from 5À3 : 1 initially changing in stepless manner to 81 : 1. In operation the bonding area of a rail is spot faced by a manually operated milling machine. The crank is rotated with a stud in the chuck 12 until the flywheel reaches 4000 r.p.m. when the clutch 25 operates to move the member 24 and body 11 to the right to connect the member 24 to the shaft 7 and apply a brake to the gearing. The different ratios of gears 4, 6 and 5, 10 cause a speed differential to occur between the member 24 and the body 11 and the chuck is urged towards the rail. When the stud engages the rail and a sufficient torque develops the clutch 14 slips to allow relative motion between the chuck 12 and drive shaft 3. The torque stops rotation of the chuck and residual energy in the flywheel is transmitted to the chuck through the spring 41 as a direct axial load by virtue of the relative rotation of members 21, 24. An electric motor may be employed to rotate the flywheel and a constant torque gearing system may be used.