Patent GB-615889-A (GB)
Title: Improvements in and relating to machines for making electric lamps and discharge tubes
IPC: H01J9/32
Filed: 1944-10-06
Abstract: 615,889. Making electric lamps and discharge tubes. BRITISH THOMSON-HOUSTON CO., Ltd. Oct. 6, 1944, No. 19219. Convention date, Oct. 6, 1943. [Class 39 (ii)] prise self-contained units, preferably each in its own housing, secured by keying to a supporting base, and comprising shafts, gears, and cams, &c., whereby the movement derived from the coupling is converted into the driving actions pertaining to the particular operation at that station. The units may be replaced or increased in number as required. The apparatus described relates more particularly to the manufacture of mounts for miniature butt-sealed electric lamps, and comprises devices for the feeding, straightening and shaping of a pair of lead-in wires, the feeding and fusion of a glass bead about the mid-portion of the wires, and the feeding and fastening of a filament to the adjacent ends of the wires. The machine comprises a turret 30, Figs. 1 and 3, provided with thirty-two work-holding heads 31 mounted on its periphery, and a corresponding number of vertically mounted conical rollers 62 disposed in a circle on its underside and arranged to engage in turn a channelled cam 61 which is rotated A machine for the automatic manufacture of sub-assemblies of electric incandescent lamps and discharge tubes is arranged so that it can be adapted readily for modifications or developments in the manufacturing process by associating with an intermittently rotatable turret a series of work stations each with its own operating mechanism provided with a coupling member whereby it is driven from the main drive of the machine and in synchronism with the movements of the turret. The mechanisms at the several work stations comconstantly by gearing connecting it to a vertical shaft 66 which is geared at its lower end to a horizontal main shaft 71 driven by a belt 73. Intermediate its ends the shaft 66 carries a gearwheel which drives a horizontal gear wheel 102 mounted for rotation on an axial column 58 and keyed or otherwise connected to a bevel wheel 101 forming the d.ive for the several couplings. An annular work table 34, Fig. 3, disposed around the gear-wheel 102 supports the operating mechanisms at the work stations and partly supports the driving couplings 33, each comprising a bevel pinion 100 mounted on a horizontal shaft 93 and engaging the gear-wheel 102. The number of couplings is half the number of work holding heads 31, so that alternate heads have couplings adjacent to them. The outer end of each coupling shaft 93 terminates in a notched flange 95, Fig. 3, and the driving spindle 91 of each unit mounted at a work station is provided with a coupling 92, Fig. 7, which has its end shaped to fit within the flange 95 and carries a radially projecting key 96 with an end 99 shaped to engage the notch in the flange. The key 96 is projected outwardly by a spring 98 and may be uncoupled by manual pressure on a rounded projection 97. Work-holding heads.-Each work-holding head 31 is-arranged to hold two leading-in wires in a definite spaced relation during the complete cycle of operations of the machine and, as shown in Figs. 1, 3 and 5, comprises a stationary centre jaw 75 and an outer pair of movable jaws 76, 77. The jaws 76, 77 are pivoted to swing in a horizontal plane about vertical pivots 81 intermediate their ends, and each jaw carries a vertical roller on the underside of its rear portion to engage a limb of a V-shaped channel in a cam plate 84 located in a slide 86 which is normally urged radially outward by a helical spring 85 carried on a guide pin 87, so that the rollers are disposed in the diverged ends of the channels, thereby holding the jaws 76, 77 closed upon the jaw 75. Wire-feeding.-The cycle of operations commences just before an empty work-holding head 31 is carried by the turret to station A, where the wire-feeding mechanism 35 is located, and results in the ends of two parallel wires 108, 109, Fig. 7, being fed upwardly towards the path of the head 31. The wire-feeding device comprises a main slide 107 located within guides in a vertical standard 90, anl an actuator slide movable within vertical guides in the slide 107 and provided with a cam roller engaging within a slot in a rotating cam disc geared to the driving spindle 91 of the unit. The driving spindle is also geared to a cam 106 which has a profiled surface engaging a roller 147 on a horizontal slide 140 which is thereby caused to reciprocate, bringing a roller 138 thereon into engagement with the slide 86, Fig. 5, on the adjacent work-head 31, and causing the jaws 76 and 77 to open. The main vertical slide 107 also carries a sub-slide 160 which moves upwardly with it and carries a pair of pivoted gripping jaws 112, 113 (the latter not shown) arranged to close upon a block 114 and grip the wires therebetween during upward movement, thereby feeding the ends of the wires up through spaced openings in a cutting-die 110. During the final part of this upward movement the lower portions of the wires are gripped between a pair if plates 121, 122, Fig. 6 (not shown), and held firmly, so that the lengths of wire held between jaws 112, 113 and 121, 122 are straightened, and stretched beyond their elastic limit and as a result retain a straight form on being fed to the jaws of the head 31. The jaws 76, 77 subsequently close upon the upper ends of the wires, and the wire-feeding devices return to their lower position, the feeder jaws 112, 113 and clamping plates 121, 122 being then opened, and the holding action of jaws 76, 77 being assisted by a pair of angularly disposed spring-pressed fingers which hold the two wires against an intermediate guide bar. Cutting.-The cutting knife 185, Fig. 7, is mounted horizontally on a plate which is slidably mounted on the offset head 111 of the main slide 107 and provided with a hooked extension at each side of the forward edge, the hooks being arranged to engage within corresponding channels in the horizontally movable slide 140 during the descent of the main slide 107,. The knife is thus coupled to the slide 140 and drawn over the die 110 to sever the wires when the slide 140 is retracted by the operating cam 106. Securing glass bead.-The leading-in wires are next indexed with the head 31 to an idle station and then to station B, Fig. 1, where a bead of ground glass is dropped over their upper ends by a feeding device 39 provided with a coupling member whereby it is driven from the central bevel pinion 100,. The bead feeding mechanism is similar to that described in Specifications 269,577 and 264,805. From station B the head is indexed to an idle station and then to station C, the first of six stations, terminating at station D, at which oppositely disposed burners 41, 411 melt the bead down around the leads and fuse it thereto. A burner 42 located at station E directs a soft reducing flame on to the bead and upper ends of the wires, and prevents too rapid cooling of the bead and also burns off the oxide formed on the wires,. Flattening leading-in wires.-At station F the upper ends of the leading-in wires are flattened in readiness for the attachment of the filament thereto, the flattening device 43 comprising a pair of anvils located on opposite sides of the path of movement of the leading-in wires and both movable to engage the wires between them, under the action of a toggle mechanism operated by a connecting-rod driven from the coupling to the central bevel drive. Bending leading-in wires.-At station G the hitherto parallel leading-in wires 36, 37 severed from the lengths 108, 109 are bent into the forms shown in Fig. 2c by the action of a downwardly movable upper die 248 and a pair of upwardly movable lower dies 249, 250, these dies being actuated by two vertically reciprocating rods operated by a cam in a unit coupled to the central main drive,. The wires are next operated on at. station H, where they are shaped as shown in Fig. 2d, by a vertically movable die 268, Fig. 18, and a pair of inwardly movable co-operating dies 269, 270, Fig. 2d. The dies are mounted on a head 272 carried on a horizontal slide 275 which is operated by a rack on its underside to bring the dies into their correct position relatively to the leading-in wires. Vertical adjustment of the head relatively to the slide is provided by a thumbscrew 279. Movement of the dies is effected by upward movement of a slide 271 operated by a vertically movable rod 292, the initial movement of the slide causing a pair of cam fingers 291 on its upper edge to enter shaped openings in horizontal slide blocks 273, 274 carrying the dies 269, 270, whereby the latter are moved inwardly. On the completion of this inward movement the die 268 acts to press the wires upon dies 269, 270 and into the shape determined by the contour of the die faces, after which die 268 is retracted and the co-operating dies 269, 270 move outwardly. The head 31 with the shaped wires 36, 37 is next indexed to station J where a filament is brought into position for mounting on the wires. The filament coiling apparatus employed is similar to that described in Specification 264,805, and presents a filament with a closely coiled mid-portion to the lip 308, Fig. 20, of a filament transferring arm 307 comprising a suction nozzle 309. The arm 307 is pivoted on a spindle 314 carrying a pinion which is operated by upward movement of a rack 335 to swing the arm clockwise into the position shown in Fig. 3. The rack 335 is mounted within a slide block 334 which is operated by a rod 341 pivoted to a cam-actuated rocking arm 340, Fig. 3, a compression spring beneath the lower end of the rack causing the latter to move upwardly with the slide block. Upward movement of the rack is limited by a stop-screw 337, Fig. 20, and continued movement of the slide block 334 brings a cam 345 on its upper face into contact with a rod 324 projecting from the adjacent end of the transfer arm 307, thereby pushing the arm