Patent GB-1179722-A (GB)
Title: Apparatus for Welding Small Elements
Inventor: RUETSCHI CHARLES
IPC: B23K11/00
Filed: 1967-02-03
Abstract: 1,179,722. Welding by pressure. C. RUETSCHI. 3 Feb., 1967, No. 5363/67. Heading B3R. Apparatus for welding small elements comprises a stationary support means for one element, an electrically conductive movable support means for the other element, a movable means for producing an acceleration of the movable support means and a switch associated with the movable means for controlling the ignition of a welding arc at a predetermined moment before the elements come into final welding contact. A support 2, Fig. 1, on a base 1 carries an insulated work-holder 3 for a workpiece 4 which is clamped by a branch 9a of a lever 9 connected to a current supply member 16. The arm 9 is connected to a spring 19 to exert pressure on the workpiece 4. A member 15 on the base 1 is connected to the other current supply member 17 and carries by means of a spring blade 12 an arm 11 which carries a holder 11d for the other workpiece 5. A lever 7 pivoted at 20 engages a spring assembly 6 comprising a bolt 6a engaging the holder 11b and slidable in a cup member 6c urged upwardly by a spring 6h. A spring 23 is connected to urge the levers 7, 11 together and a spring 21 urges the lever 7 upwardly. A cam 8 acts on the levers 7, the cam being turned clockwise against a spring 22 into an initial position in which it is locked by a detent 30. A conductor 24 is arranged on the cam and an adjustable arm 25 has a contact 26 to co-operate with the conductor 24 to close the welding circuit to the holders. To load the workpiece 4 an eccentric 13 is rotated to raise the arm 9 and the arm 11 is turned at the same time to permit loading of workpiece 5. The eccentric is returned to its initial position when the workpiece 4 is clamped and the workpiece 5 rests on the workpiece 4. The cam 8 is turned clockwise and held by the detent 30 and then released. When the track 24 reaches contact 26 current flows through the workpieces which creates an arc and the workpiece 5 is raised explosively to draw the arc, which may be supported by magnetic elements 29a, 30a. Just after the arc is drawn the cam causes lever 7 to press workpiece 5 against the plate to extinguish the arc. In a modification, a workpiece 31, Fig. 2, is held in a support 33 rotatable into a horizontal unloading position and a workpiece 32 is held in a support 38 on a current supplying arm 37 pivoted at 37<SP>1</SP>. The arm 37 is pushed towards the support 33 by a spring F1 and a lever 39 carrying a mass M2 is urged towards a part of the arm 37 by a spring F2 but is held latched by a member 44. Between the lever 39 and arm 37 is a spring blade 41 forming a contact of a switch for the welding current. In operation, the workpiece 32 is held against the workpiece 31 by spring F1, latch 44 is released so that mass M2 first engages plate 41 to render a valve in the primary circuit of a transformer conducting so that a condenser may discharge thereinto, a current then flowing in the secondary across the workpieces, and then the mass M2 contacts the lever 37 to move the lever 37 against the spring F1 and raise the workpiece 22 from workpiece 31 to strike an arc. The workpiece 32 is then pushed back by the spring F1 against workpiece 31. The apparatus may weld a leg to a plate of a cuff-link and it is stated that the workpieces may be spaced apart when the current supply is connected, high frequency being employed to start the arc. The mass M2 may be replaced by a wheel or eccentric having a switch device on the shaft of the wheel.