Patent GB-350635-A (GB)
Title: Improvements in the manufacture of electric incandescent lamps and the like
IPC: H01J9/32
Filed: 1930-04-07
Abstract: 350,635. Making electric incandescent lamps. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London.- (Patent-Treuhand Ges. fur Elektrische Gluhlampen; 11, Ehrenbergstrasse, Berlin.) April 7, 1930, No. 11024. Convention date, April 6, 1929. Addition to 337,301, [Class 39 (ii), Electric lamps, Incandescent]. [Class 39 (ii).] The machine described in the parent Specification is modified by providing as an abutment for the leading-in wires two pairs of jaws mounted below the grippers for the foot-tube, the limbs of the inner pair of jaws being provided with notches to receive the leading-in wires which are clamped therein by the outer pair of jaws, the jaws being so arranged that, after the foot-tube has been softened by heating, they can be forced apart, thereby causing the leading-in wires to be drawn apart and producing a corresponding widening of the end of the softened foot-tube. As in the parent Specification, the intermittently rotating holding-heads are provided with spring jaws 13, Fig. 4, for gripping the small exhaust tube 12, and jaws 20 for gripping the foot-tube 21. Bolts 31 depending from the arms 3<1> of each holding-head are connected by a bridge-piece 55 provided with a longitudinal slot between parallel side plates 57, 58, Fig. 6, which form end bearings for pivots 59<1> .. 621 carrying the two pairs of jaws 59, 62 and 60, 61. The inner pair of jaws 60, 61 are normally kept closed by a compression spring 63 at their lower their, upper ends being provided with recesses 40 beneath narrow head-pieces 41 formed with wedge-shaped notches through which the leading-in wires 38 pass from the foot-tube 21 to supporting surfaces 39 at the bottoms of the recesses 40. The outer pair of jaws 59, 62 are provided with inwardly projecting noses 65, 66 which, when the jaws are in their closed position, clamp the leading-in wires within the wedge-shaped notches of the inner jaws. The independent opening of the outer jaws 59, 62 is controlled by a vertically displaceable push rod 67 with forked upper limbs 68 which, in the raised position of the rod compress the lower ends of the jaws. The opening of the inner pair of jaws, with the outer pair gripping the leading-in wires against them, is effected by means of a transverse bolt 70 which is displaceable within vertical slots 71 in the plates 57, 58 and moves within a tapering recess 72, 73 formed by the jaws 60, 61. The laterally projecting ends of the bolt 70 carry rollers 74 which coact with cam faces in the path of the rotating carrier. In the operation of the machine a small exhaust tube 12 is inserted either by hand or automatically within the spring jaws 13 at the initial or starting position, a foot-tube 21 being inserted within the jaws 20 at the next position. Subsequently the forked rod 67 is raised automatically and the outer jaws 59, 62 are moved away from the inner jaws 60, 61, enabling the operator to insert the leading-in wires 38 down through the foot-tube. While the holding-head is still in this position the rod 67 drops, and the outer jaws move inwardly to clamp the leading-in wires within the wedge-shaped notches 42 of the inner jaws, while an automatically controlled push-rod lowers the exhaust tube 12 to the requisite height within the foot-tube 21. In the next three positions the lower portion of the foot-tube is softened by laterally directed burner flames and becomes concentrated into a nodule which is widened, as shown in Fig. 9, when the leading-in wires are separated obliquely by the outward movement of the two pairs of jaws, produced by the rollers on the end of the lateral bolt 70 running over a cam surface. The pedestal is subsequently pinched between clamping-members and allowed to cool before the outer jaws are opened to release the leading-in wires.