GB456634A - Improvements relating to the manufacture of helical filaments - Google Patents

Abstract

456,634. Shearing. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London.-(Assignees of Patent -Treuhand- Ges fur Elektrische Gl³hlampen; 11, Ehrenbergstrasse, Berlin) April 1, 1936, No. 9647. Convention date, Nov. 8, 1935. [Class 83 (iv)] Coiled lamp filaments 2, with a straight attaching piece at each end, are cut from a continuous length comprising coils 2 with intermediate straight or less coiled pieces 3, the cutters 28, 29 being actuated by a photoelectric device when such device views the change in projected light area from a coil, to a straight piece. When a straight piece 3 passes a slit, the light source 15 projects more rays on the light sensitive receiver 10, which, through an amplifier 61, energizes an electromagnet 58, so freeing a double pawl 56 to drop on a continuously rotated ratchet wheel 44 whereby the pawl and its carrying arm 53 is rotated, and takes with it the tubular sleeve 45 on which is mounted a second arm 47 carrying a pin roller 48 giving intermittent rotation to the slotted Geneva wheel 49. This wheel 49 rotates step by step its shaft 51 on which is a gear 52 driving a shaft 37, the cam 36 of which rocks the cutter carrying bell cranks 30, 31 to actuate the cutters 28, 29 thereon to chop off the required filament which is blown out by an air blast. When the light is interrupted by the succeeding coil in the continuous length the electromagnet is de-energized so that a spring 65 pulls down the finger 64 in contact with the heel 57 of the pawl 56 as it is rotating with the ratchet wheel 44 and so raises it therefrom and stops the actuation. The cutters 28, 29 are spaced apart a distance slightly less than the centres of two straight pieces between the coils, and the machine is timed to actuate both cutters when a point a on Fig. 3 assumes the position c so that cutter 28 cuts the intermediate part 3 slightly in front of its centre, and when the point b arrives at d the cutters are actuated again, and the cutter 29 cuts slightly behind the centre of the straight leaving a part 311 cut off as waste, thus making the two end pieces or pigtails equal. The machine may also be used for cutting a filament comprising two coils continuous with a short straight piece where it is connected to the lamp by pigtails. In this case the photo-electric apparatus is modified to operate the cutters only at the long straight portions between the coils. The wire is gripped and fed by an endless belt 5 and a pulley 4.