Patent GB-717940-A (GB)
Title: Improvements in and relating to lamp base filling machines
IPC: H01K3/18
Filed: 1951-12-18
Abstract: 717,940. Lamp base filling machines. BRITISH THOMSON-HOUSTON CO., Ltd. Dec. 18, 1951, [Dec. 22, 1950.] No. 29609/51. Class 39 (2). A non-intermittent continuous action machine for inserting cement paste into a lamp base 1 comprises a roller chain 10, Fig. 2, driven by a sprocket 13 and passing around a sprocket 14 and two relatively larger sprockets 11 and 12, the links of the chain being provided at regular intervals with work holders 22 comprising jaws 24, 25, Fig. 3, which are opened automatically and receive lamp bases from a chute while the chain is moving around with sprocket 11, the cement paste being injected within the bases while they are being carried around the periphery of the sprocket 12, which has a series of filling units 30 comprising radially reciprocable cement injecting plungers arranged to engage the bases in co-operating work holders over a predetermined angle of travel during which a fixed cam 36 at the centre of the sprocket 12 operates radial rods 35 associated with the respective plungers. The mechanism for feeding the lamp bases into the work holders is preferably that described in Specification 717,941. In the example the sprocket 12 makes one anti-clockwise revolution per second and carries twelve cement injecting devices, so that the output of cement-filled bases is twelve per second, the base-feeding mechanism associated with sprocket 11 being operated correspondingly; alternatively the bases may be fed manually at the required rate at sprocket 11. Means are provided to prevent the paste-injecting mechanism from functioning if a base is not present in a holder to receive the paste. The base-holders 22, mounted at intervals on a chain 10 of conventional pattern, are disposed so that they are spaced at 30 degrees intervals during the period of wrap of the chain around the sprockets 11 and 12. Each holder 22 comprises an L-shaped frame 23 carrying a pair of spring-controlled pivoted jaws 24, 25 and a bell-crank 26 for actuating the jaws, which swing in a plane normal to that of the sprocket 12. A roller 27 at the free-end of the bell-crank 26 rides over an arcuate cam track 28 during a part of the period of wrap of the chain around the sprocket 12 in order to effect a temporary release of the grip upon a lamp base. Each filling unit is designed to fill a base with cement paste during the period from 90 degrees to 270 degrees travel on sprocket 12, the paste being supplied to the several units by flexible rubber tubes 32, Fig. 4, which receive paste from a central revolving distributing head 33 mounted on top of the sprocket 12 and fed from a stationary container below the table of the machine. The twelve filling units on the sprocket 12 each comprise a fixed housing 40 (shown in part plan in Fig. 5a and in vertical section in Fig. 5b), within which a push rod 35 is slidably mounted and normally extended outwardly of the housing by a helical spring 37 which holds an end roller 38 against a central cam 36. An annular sleeve 42 slidable within the housing 40 and slidable relative to the push rod 35 carries a vertical diametrical pin 43 which extends upwardly into a tongue 44 which is slidable within a longitudinal groove 45 in the upper surface of the housing 40. The pin 43 passes through a longitudinal slot 46 in the rod 35, thereby allowing the rod to move to the extent allowed by the slot without interfering with the position of the sleeve 42. A plunger 49 slidable within the hollow outer end of the rod 35 has a limited longitudinal movement determined by a slot 51, therein engaging a transverse pin 52 projecting through the hollow part of the rod 35, and thus acts as a valve which controls the exit of cement paste from a nipple 48, mounted in the sleeve 42, into a lamp cap, there being an annular passage 50 behind the head of the plunger 49 to allow the cement to pass into a lamp base as the rod 35 is pushed forwardly in the direction of the base in alignment with it. The head of the plunger 49 then extends into the lamp base, which arrests its further movement while the end of the rod 35 continues to move and forces the cement from the annular space 50 into the lamp base, as shown at 7, Fig. 1. In the event of there being no lamp base in the holding jaws aligned with a filling unit, a normally compressed spring 47 within the housing 40 is free to expand and push the sleeve 42 outwardly, in which position the cylindrical nose portion 53 of the sleeve covers the annular space 50 and confines the paste within it. To facilitate the alignment of the base with respect to the filling- unit the cam track 28 commences to force the bell crank 26 upwardly at the 120 degrees position of the sprocket 12 and partly releases the hold of the jaws 24, 25 upon the base located between them, thereby allowing the plunger 49 and annular sleeve 42 to determine the final alignment. The jaws are permitted to close to grip the base again at the 240 degrees position. The bases may be ejected on arrival at the 300 degrees position of the sprocket 12; alternatively they may be carried through fire banks 54, Fig. 2, and heated by flame jets to form a skin on the surface of the cement paste which will prevent the bases from sticking together during storage. The bases may be held in the machine with their axis vertical when a fluid form of paste is used for filling, or, if held horizontally, a ratchet device may be associated with each base holder for indexing the bases through a small angle periodically. The filled bases are preferably ejected by an air blast on arrival at an ejector sprocket 15 carried on a stationary axial shaft through which compressed air is fed to a diametrical slot 65, Fig. 6 (not shown) arranged so that it is periodically aligned with one of four radial nozzles 58 when the latter is adjacent to a base carried around the sprocket 14, the jaws of the base holder being simultaneously opened by a cam track 66 to release the base which is then blown out of the holder.