GB592084A - Apparatus for the electrical welding of studs and the like - Google Patents

Abstract

592,084. Welding. ENGLISH ELECTRIC CO., Ltd., and HASSLER, E. H. H. Oct. 3, 1944, No. 18891. Addition to 579,711. [Class 83 (iv)] In an apparatus for welding studs &c. to plates &c. of the kind in which an arc is struck by melting a fusible insert or extension on the stud, the, stud holder being withdrawable against a biassing force by pressing the end of the stud against the plate and temporarily holding it in withdrawn position as described in the parent Specification, the stud holder comprises one or more balls or cylindrical or barrel-shaped rollers between a tapered surface on one of the relatively slidable members and a parallel surface on the other, the angle of taper being such as to allow the stud holder to be moved freely into the gun and either to lock it automatically on an attempt at return movement or such as to allow it to move freely in both directions, means being provided in the first instance for unlocking the device and permitting return of the stud-holder and in the second instance for applying and removing a small force axially along the device to load one or more balls sufficiently to cause them to lock the stud holder and then to release it at the required time. In the tubular body 1 of the apparatus which is provided with adjustable legs 6 and a handle 2 of the domed type, is mounted a stud holding plunger 3 which is pressed forward by a spring 4. The body contains a collar 8 with a frusto-conical interior between which and the plunger are carried a ring of balls 9. In the self-locking type of device, the balls may be mounted in a cage 10 carried by polepieces 11 which are attracted upwards to complementary polepieces 12 against the action of light springs 13 when magnet coils 5 are energized so as to free the plunger 3 so that at some time after the arc is started the stud may be pressed by the spring 4 into contact with the plate to complete the weld. The collar 8 may be provided with projections 8a resting on a spring washer 14 so that the stud holder may make a slight return movement before being locked. If the angle of taper is greater than the friction angle so that the device is not self-locking, the springs 13 are made heavy enough to exert a force to lock the balls against the opposed surfaces, the cage 10 being replaced by a ring to press on the top of the balls. In a modification, the internally coned ring 8, Fig. 2, houses an annular magnet coil 5, which is energized so as to attract an armature 16 so that the non- magnetic pressure ring 17 thereon exerts pressure on the balls to lock the plunger. When the coil 5 is de-energized, the spring 4 pushes down the plunger. In a further form, Fig. 3, the plunger 3 carries the coil 5 and the spring- returned armature 20 has screws 19 for supporting the loosely mounted externally coned collar 15. The balls 9 may be supported by the flange 3b on the plunger. In some cases, the angle of taper or the make-up force may be insufficient to hold the plunger quite still, so that the stud slowly moves towards the work, or the force exerted by the magnet 5 may be first reduced from an initial high value to one which is insufficient for this purpose. The tripod legs may be adjusted and then locked by nuts 7 in a ring 22 which may carry a spring- pressed ball catch 23 entering arcs of the three grooves 1b spaced around the body to ensure that the legs always bear the same relationship to the handle. Specification 584,695 is referred to.