Patent GB-814985-A (GB)
Title: Electric lamp making machinery
IPC: H01K3/28
Filed: 1956-06-14
Abstract: 814,985. Making electric lamps. SYLVANIA ELECTRIC PRODUCTS Inc. June 14, 1956 [June 16, 1955], No. 18469/56. Class 39(2) Lamp making machinery comprises a pair of machines 12 and 14 which each perform a lamp-making operation and have a circular turret 16 located between them whereby a lamp can be transferred from a work-holder on machine 12 to a gripper on the turret 16 and thence conveyed and transferred to a work-holder on the machine 14, means being provided for indexing the turret in timed relation to the workholders of the two machines and through a path having portions which coincide with portions of the paths of the workholders of the machines 12 and 14, during which coincident periods a transfer device is operative to transfer a lamp from the machine 12 to the turret while another lamp is being transferred from the turret to the machine 14, at least one of the said machines being adapted to perform an operation on a lamp while it is held by the turret grippers. The two machines 12 and 14 may be of either the circular rotary indexing or straight-line indexing type, and the interposed turret 16 may be associated with one or more operating stations of its own. In the example a lamp is exhausted flushed, gas-filled and sealed (or "tipped") while on the machine 12 which is of the circular turret type, and at a station X is transferred to the turret 16 which is associated with two workstations X-2, and X-3, whereat the two leading-in wires of the lamp are straightened and aligned in readiness for threading through the eyelet holes of a lamp cap held in a work-holder on the machine 14 at station Y, at which station the transfer of the lamp to the latter machine is effected. Finishing operations are carried out in the machine 14, where the lamp cap is cemented in position and the leading-in wire soldered to the metal eyelet of the cap contact. Both the machines 12 and 14 are of dual character i.e. with twin work stations, and with double indexing to move pairs of lamps from one pair of twin stations to the next, the turret 16 being adapted similarly. The turret 16 comprises a circular horizontal plate 20, Figs. 1 and 2b secured at the upper end of a vertical shaft 72 and provided around its circumference with a series of gaps 26 each with a marginal seating for the bottom of a lamp bulb 28 which is held in position by a pair of co-operating jaws 30, 32 mounted on vertical shafts in an upstanding flange 24 adjacent to the gap 26. The jaw 30 is elongated rearwardly and carries a roller 34 co-operating with a cam 40 mounted on top of the turret, the lower ends of the jaw-carrying shafts being gear connected so that they open in unison against the action of a spring 36 connected between the arms. Because the adjacent pairs of jaws are closely spaced alternate pairs are disposed at different levels. Indexing of the turret 16 is effected by a chain and sprocket drive from a cam shaft 50, Fig. 2b, to a shaft 58 carrying a barrel cam 60 provided with an inclined groove on its face to engage a succession of rollers 62 on the underside of an index wheel 64 on a vertical shaft 66, and a hollow shaft 72, which is slidable upon the shaft 66 and coupled so that it rotates with that shaft, has the turret plate 20 secured to its upper end. The cam plate 40 which operates to open or close the jaws of the turret grippers is formed with cam tracks opposite to the work stations X and Y and is rocked through a limited arc about its axis by linkage comprising a rocking- lever 104 which is operated by a cam 100 on the shaft 50, as shown in Fig. 1. The grippers on the anti-clockwise rotating turret 16 are held open by the action of the cam 40 when they are at station W, in readiness to receive a lamp at station X. Meanwhile a lamp on machine 12, in a working head at a position corresponding to position W of turret 16 and held bulb downwardly by its exhausting tube 121 is being subjected to preheating flames directed upon the exhaust tube near to the bulb neck, the upper end of the exhaust tube being clamped in a head 120 which has carried it through stations at which it has been connected to vacuum pumps and sources of flushing and filling gas. Figs. 1 and 2b show the completion of the tipping operation effected by a pair of oppositely directed gas nozzles 122 mounted on the ends of rearwardly extending gas pipes 123, the nozzles being supported on a carriage comprising a pair of collars 119 slidably mounted on a pair of spaced vertical rods 124. Vertical links 125 pivoted to the respective collars 119 are pivoted at their upper ends to a pin 126 carrying a counter-weighted bracket 127 on which the gas pipes are clamped. The burners may be raised and lowered by a cam-actuated linkage connected to the collars 119 and a backward and forward rocking motion is also imparted by means of a vertically slotted plate 134 mounted on a rocking- lever 136 pivoted on a rod 138 at its lower end. The slot 132 in the plate 134 receives a pin 130 projecting laterally from a link 125. Lever 136 is rocked through a camactuated linkage 144, 146, and 148, Fig. 2b the latter being secured to the pivot rod 138. In operation the turret jaws 30, 32 are open at station W and the turret is in its lower position, and as indexing begins, the tipping or sealing torch rises and swings rearwardly. The turret rises as it moves towards station X, and the jaws begin to close upon the bulb, whereupon the turret and the burner torch begin to drop together, the exhaust tube now being plastic. The jaws finish closing on the bulb and before the turret reaches its bottom position the burners move out of position and also rise, after which the turret 16 and exhaust machine 12 rotate to a new index position. Leading-in wire straightening:- The leading-in wires, which were bent downwardly prior to the sealing of the lamp on machine 12, in order to avoid their being burned off by the sealing flames, are bent in two stages at stations X-1 and X-2 respectively, into the requisite positions for capping the lamp, one wire being bent downwardly in order to be trapped between the metal cap and the bulb neck, and the other bent vertically upward for threading into the centre eyelet of the cap. At station X-1 one of the downturned leading-in wires of each of the two lamps held in two adjacent sets of grippers is bent upwardly by an upwardly swinging kicker-bar 173 Figs. 1 and 4 which extends transversely between the ends of a pair of levers 208, 210 the levers being operated simultaneously through a linkage 202 controlled by a cam-operated vertically reciprocating shaft 196, Fig. 1, and Fig. 3 (not shown). The bars 173 gives the leading-in wire 171 an upward kick, but since the wire is resilient it springs back somewhat and is therefore subjected to straightening by gripping between pairs of jaws at station X-2, Fig. 1. A jaw at the end of a fixed arm 174 co-operates with a jaw on a pivoted lever 176, two such arrangements being mounted on a fixed bracket 232 adjacent to the turret 16, with the respective pivoted jaws linked together and operated by an extension of the camoperated linkage that operates the kicker bars 173 at station X-1 the timing being such that the jaws grip upon and thus straighten a wire while the turret 16 is descending. The two lamps are next moved to an idle station X-3 and then to the wire-threading station Y. Wire-threading and lamp finishing:-At station Y the lamps are transferred in successive pairs to pairs of heads on the finishing machine 14, which is double indexed in synchronism with the turret 16. Each head comprises a bracket mounting a pair of jaws 300, Fig. 2a, to hold a lamp cap or base 304 mounted therein at a work station preceding station Y of the machine 14, and above the jaws is mounted a flat plate 302 which co-operates with -the jaws 300 to hold a cap 304 in position, the plate being also apertured to receive and locate a metal eyelet placed upon the crest of the cap. Each head also has a depending vertical rod 306 in which is slidably mounted a bracket 308 provided with a spring- loaded ball clamp of the kind described in Specification 809,557, arranged to hold the bracket in any position into which it is raised upon the rod 306. Three upwardly diverging fingers 312 on the bracket provide a seat for a lamp bulb 28 when finally released from the grippers of turret 16. The work holder also carries a pair of inverted jaws 320 which together form a funnel for facilitating the threading of the vertically projecting leading-in wire 171 into the eyelet on the cap. Each inverted funnel jaw 320 is carried by an arm 330 extending laterally from a collar 332 which is pinned to a vertical stub shaft journalled in a bracket 336 and carrying a pinion 340 fixed on its upper end the pinions on the two shafts being meshed and one of them engaged also by a horizontal rack bar 342 which can be reciprocated by a rocking-lever 352 in abutment with its outer end. Movement of the rack bar 342 in one direction causes the funnel jaws to open in opposition to a tensioned spring 344 connected between their arms 330. Means are provided to swing the funnel guide and its mounting unit out of the way during the attachment of the cap to the lamp bulb. For the wire threading operation the arm 352 is retracted to allow the spring to close the funnel jaws and the bracket 308 supporting the lamp is lifted so that the leading-in wire extending upwardly therefrom enters the funnel. At the same time a threading-needle 322 is brought downward through the eyelet of the lamp cap 304 and into the embrace of the funnel jaws, which close upon it after it reaches its lowermost position, thereby centring the needle within their upper outlet so that the ascending leading-in wire is guided into the needle. The funnel jaws are next opened, and with their mounting- bracket 336 are swung out of the way into the position shown i