GB676069A - Apparatus for the electric butt welding of studs or the like to curved or plane surfaces - Google Patents

Abstract

676,069. Welding by pressure; shearing. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. Oct. 11, 1950 [Oct. 18, 1949], No. 24835/50. Class 83 (iv). Apparatus for the electric butt welding of metal studs formed from wire material comprises means for moving the wire through a straightening means and cutting a stud therefrom and pressure fluid actuated welding tongs for supplying welding current and applying welding pressure to the cutoff stud. In an embodiment, a unit includes welding tongs 4 comprising an arm 7 adjustably secured, to allow different stud lengths, to a hollow piston rod 9 and pivotally carrying at 20 an upper arm 8 to which is pivoted a cylinder 21 whose rod 22 is pivoted to the arm 7. Cutting means 1 comprise arms 3 pivoted to the rod 9 at 16 and to cylinders 17 supported on rods 18 which are pivoted at 19 to the rod 9. The rod 9 enters a cylinder 10 adjustably secured to a frame 11 carrying also a straightening device 14. Wire 13 from a reel passes through the device 14, the piston 9, edges 2 of the means 1 and jaws 5, 6 on the tongs 4. In operation fluid pressure is applied in the cylinder 10 to move the tongs 4 and the means 1 from the position of welding shown, with fluid pressure applied in cylinders 17, 21 to open jaws 5, 6 and edges 2. The means 1 and tongs 4 slide on wire 13 a distance equal to a stud length. Low pressure is applied in cylinders 17, 21 to effect gripping of the wire 13 by the edge 2 and jaws 5, 6 and fluid pressure in the cylinder 10 moves the whole to the left until the wire 13 contacts the work 15 when higher pressure is applied in cylinders 17, 21 to effect cutting of the wire 13 by the edges 2. Current is then supplied to the work 15 by a contact 31 pivoted to the arm 8 from a transformer 24 and to the stud 13 by the arm 8 to permit welding. A single arm 7 is employed for welding studs to flat surfaces and a double arm 7 for welding to curved surfaces. A device to control fluid pressure, welding current, timing of operation &c. is provided. In lieu of supplying different pressures to the cylinders 17, 21 for seizing and cutting respectively, a mechanical device is described which with full pressure in the cylinders permits the cylinder 17 only limited movement transverse to the rod 9 for a predetermined distance, thus limiting the pressure exerted by the edges 2. The restriction is removed to allow cutting. The cutting operation may take place before the wire 13 engages the work 15 so that relative movement of the stud 13<SP>1</SP> and cut wire 13 results. The edges 2 provide an abutment for the stud 13<SP>1</SP> during welding. A plurality of units may be employed, mounted on a common curved or straight support.