GB900281A - Improvements in or relating to electric flash butt welding machines - Google Patents

Abstract

900,281. Welding by pressure. WUPPERMANN G.m.b.H., THEODOR. Jan. 15, 1959 [Jan. 15, 1958], No. 1586/59. Class 83 (4). An electric flash butt welding machine comprises a main frame, a first pair of jaws for clamping a first workpiece, a longitudinal subframe supported at both its ends by said main frame so as to be longitudinally displaceable therein at least at one end, said sub-frame consisting of four parallel ties fixed in pairs to two cross-members at said one end, a carriage carrying a second pair of jaws for a second workpiece and movable longitudinally of the subframe on guides in the main frame, thrustproducing devices arranged in pairs, or as a single pair, and reacting on the cross-members so as to act on the carriage without acting directly on the main frame, the devices being capable of producing equal parallel forces on each cross-member and the arrangement being such that, as seen in transverse section, the axes of the four ties are at the corners of a rectangle and the resultant lines of action of the two forces are located mid-way between two corners of the rectangle and on opposite sides thereof and such that the said axes and lines of action are parallel to and symmetrically disposed about the axis of the workpiece which is located at the point of intersection of the diagonals of the rectangle. The machine has workpiece clamping jaws 3a, 3b on columns 5a, 5b guided in C- shaped carriages 6a, 6b and urged to effect clamping by pressure cylinders 4a, 4b. The carriage 6a is fixed to a C-shaped upright 7 of the machine and the carriage 6b is movable on a lower guide rod 8 and on an upper guide rod 10, the upper rod passing through a vertically movable block 9 in the upper part of the carriage. The rods 8, 10 pass through the carriage 6a and are secured to the upright 7 and a further similar upright 11. The portions of the guide rods between the carriages are protected by sleeves 22. The carriage 6b is movable during flashing by cams 12, during retraction by cylinders 14a, 14b and during upsetting by plungers 13a, 13b extending from cylinders 15a, 15b. The cylinders 15a, 15b are secured to crossmembers 16a, 16b and are slidably mounted in the upright 11. Each cross-member is connected to one end of a pair of rods 17 fixed at the other end to the upright 7 and mounted with clearance in the carriages 6a, 6b and in the upright 11. The rods and cylinders 15a, 15b may be mounted in bushings which are slowly rotated. In operation, the workpiece 1, 2 are clamped in the jaws and the current switched on. The cams 12 and cylinders 14a, 14b cause the workpieces to move into and out of contact to effect preheating and finally the cams 12 move the workpieces together and plungers 13a, 13b are moved to cause upsetting and the current is switched off. During upsetting, the reaction forces are taken by the cross-members and the rods, which latter extend slightly. The guide members 8, 10 and rods 17a, 17b may be cooled by liquid passed therethrough. Two or more pairs of upsetting plungers may be used, one plunger of each pair being mounted on each cross-piece.