Patent GB-733841-A (GB)
Title: Improvements relating to mount making machines for electric lamps and similar devices
IPC: H01K3/10
Filed: 1953-11-30
Abstract: 733,841. Making mounts for electric lamps and similar devices. BRITISH THOMSONHOUSTON CO., Ltd. Nov. 30, 1953 [Nov. 29, 1952], No. 33239/53. Class 39 (2). In a mount-making machine for electric lamps and similar devices a stem provided with a pair of leading-in wires extending downwardly as opposite sides of the longitudinal axis thereof it advanced to a succession of work stations at the first of which the leading-in wires are trimmed to different lengths, and mechanism at a further work station bends the respective ends of the leading-in wires inwardly across the axis of the stem at spaced positions therealong into a position to receive a filament between their end portions and substantially in alignment with the said axis, means being provided for securing the filament to the ends of the leading-in wires. The mounts are supported by pairs of jaws 7, 8 and 9, 10, Fig. 2 (not shown), which grip the exhaust tube 11 and maintain it in a vertical position with the leading-in wires extending downwardly from the stem. A series of such jaws are mounted at intervals along an intermittently indexing conveyer 1, Fig. 1, of the type described in Specification 390,807, associated with adjacent work stations at which they are halted. At station A, Fig. 1, each of the leading-in wires 3 and 4 is dressed or trimmed by a pair of die-blocks 18, 19, Figs. 5 and 6, on a jaw 22 co-operating with die blocks 20, 21 on a jaw 23, the blocks 18 and 21 having projecting lips 24 which co-operate with the sharp lower edges of the blocks 20 and 19 respectively to shear the leading-in wires. The die blocks 18 and 20 are in a plane above that of the die blocks 19 and 21 in order to shear the lead 3 shorter than lead 4. The die-carrying jaws 22, 23 are pivoted on a pin 26 in a support 27 which has a screw-threaded stem secured adjustably in a standard 28, and the closing of the jaws is effected by upward movement of a toggle arrangement comprising a pair of links 30, 31 connected between the lower ends of the jaws and a pin 34 at the upper end of a cam-operated vertically-reciprocable rod 29. Rollers 36 on the pin 34 travel within vertical slots 37 in the standard 28 to guide the upper end of rod 29. During the final closing movement of the jaws 22 and 23 the faces of the die blocks press upon the leads 3, 4 and flatten then to the extent that plane surfaces are formed thereon to the full height of the die blocks 19 and 20, whereupon the jaws are separated by downward movement of the rod 29. At station B open hooks are formed in both leads 3 and 4 by mechanism which bends the lower half of the flattened end portions sidewards and then upwards to positions adjacent the main portions thereof. The bending mechanism comprises a vertical slide 47, Fig. 7, with an outwardly projecting arm 46 formed with a pair of laterally spaced upward extensions carrying backing-members 45, 45<SP>1</SP> respectively, upward movement of slide 47 being accompanied by downward and sideward movements of anvils 48, 48<SP>1</SP> which are swung upon side portions of the leads 3 and 4 and press them against the respective backing- members. The anvils 48, 48<SP>1</SP> are carried on supporting arms 50, 50<SP>1</SP> which are pivoted at 49, 491 and connected by compressible sleevelike connecting-rods 55 at their rear ends to forked projections 51 which extend rearwardly from the slide 47. The compressible connecting-rods each comprise a compression spring 54 between a head 56 and lower end of the sleeve 55, with the result that the anvils move initially with the slide 47, and excess motion of the latter is absorbed by the springs. Stop-screws 57 and 57<SP>1</SP> limit the movement imparted to the anvils. The vertical movements of the slide 47 are effected by a vertically-reciprocating rod 60 under the action of a cam driven by the main cam-shaft 16, Fig. 4 (not shown). The flattening of the ends of the leading-in wires is followed by bending into hook form by fingers 72, 721, Fig. 8, carried on the inner ends of rotary spindles 74, 74<SP>1</SP> mounted in journals 75, 75<SP>1</SP>, the outer ends of the latter being provided with pinions 77, 77<SP>1</SP> which engage racks 76, 761 formed on secondary vertical operating-rods 67, 67<SP>1</SP> mounted on a cross-bar 69 on the vertically reciprocating rod 60 controlling the action of the anvils and their cooperating backing members 45, 45<SP>1</SP>. Movement of the vertical rods 67, 671 takes place against the compression of springs 66 thereon, so that when the rod 60 descends the operating members are returned to their inoperative position. The stem 2 is next indexed to station C, where the corresponding end portions 78, 79, Fig. 22, of the leads 3, 4 are bent towards one another and lie across the longitudinal axis of the stem 2. This bending mechanism is advanced horizontally into its operative position by a carrier slide 81, Figs. 9 and 12, mounted in guides on a supporting standard adjacent to the path of the carrier. The slide 81 inserts anvils 83, 84 thereon between the leading-in wires 3, 4 at elevations above their hooked ends and also slightly above the position at which they are to be bent, and also carries pivoted bending-jaws 85, 86 to positions on opposite sides of the leading-in wires. The anvils 83, 84 are attached to the front and side faces respectively of a block 87, Fig. 12, supported by a horizontal pivot 89 through an upstanding projection 88 on the front of the slide 81, so that when movement of the slide brings an ear 90, Fig. 9, against a stop-screw 91 in a stationary bracket 92 the block 87 is pivoted a limited amount about the pin 89 against the resistance of a helical spring 93 in a pocket in the slide 81. Operative movement is imparted to the slide 81 by a sub-slide 100 which is movable within deep longitudinal guides in slide 81 and connected by a horizontal link 106 to a cam-controlled bell-crank. A compression spring 102 is located between the slides 81 and 100, so that they move together until slide 81 is halted, whereupon slide 100 continues to move, compresses the spring 102, and produces advancement of a plate cam 125 provided with a pair of divergent slots 128, 128<SP>1</SP>, Fig. 9, which engage rollers 126 mounted on screws 127 on the rear ends of the jaws, 85, 86, thereby causing the latter to close upon the wires. The longer lead 4 is the first to be engaged and is caught in an end slot 116 of a locating finger 117 on the jaw 86 during the early part of the movement of the latter and positioned correctly relative to the anvil 84. Further closing movement of the jaws advances the clamping blocks thereof against portions of the leads 3, 4 and clamps them upon the anvils 83, 84, respectively. The jaws carry teeth 120, 121, Fig. 11 (not shown), which project therefrom against the end portions 78, 79 of the leads and bend them into substantially right-angled form around the anvils 83, 84, the main portions of the leads meanwhile being prevented from bowing out of position by spring-pressed clamping blocks 118, 119, Fig. 11 (not shown), mounted slidably below cover-plates 122, 123 on the jaws. Finally, the block 87 supporting the anvils 83, 84 is tilted about its horizontal pivot, causing the lateral parts of the bent leads to be wiped around the anvils and into grooves along the top surfaces of teeth 120, 121, Fig. 11 (not shown), on the jaws 85, 86, causing the ends 78, 79 of the leads to be located in the planes of their respective main portions. The anvils and associated parts of the leadbending mechanism are retracted from the path of the stem prior to its movement to the next work station D at which a coiled filament or cathode 130 is mounted between the ends of the leads 3, 4 with the aid of transfer mechanism shown in Fig. 13. Mechanism which may be of the kind described in Specification 390,807 presents the filament 130 on an elevator 132 at position D<SP>1</SP> from which it is taken in a groove 135 in the head end 134 of a tubular transfer arm 133 when the latter is in its rearward position. The transfer arm 133 is rotatably mounted in a sleeve 140 carried by a slide 145 and is connected to a vacuum source by a flexible tube 141 at its rear end, so that a filament picked up from the elevator 132 is carried forwardly towards the leading-in wires and at the same time turned into an almost vertical position by axial rotation of the arm 133. This rotation is effected by a slidable rack bar 165 which is mounted at right-angles to the arm 133 and engages a gear segment 166 on the latter, a longitudinal movement being imparted to the rack bar by a roller 163 at its other end riding upon a cam block 164. The ends of the filament are thus brought before the open ends of the hooks in the leading-in wires at the end of the sliding movement of the transfer arm 133, whereupon a slight final rotary movement is given to the latter by an inward rocking of an .arm 170 carrying the cam block, so that the ends of the filament are positioned within the open hooks of the leads 3, 4. The hooks are next closed upon the ends of the filament by a clamping mechanism which is mounted upon a vertically movable carriage 185, Fig. 17, at station D and normally held in its lower inoperative position below the path of the stem and leading-in wires 3, 4 during the insertion of the filament and subsequently lifted to bring pairs of pivoted clamping jaws 183, 183<SP>1</SP> and 184, 184<SP>1</SP>, Fig. 16 (not shown) into the operative position. Vertical movement is imparted to the carriage 185 by an operating rod 194 carrying a slide 193 which is connected to the lower end of the carriage by two springs 195, a stop being provided to limit the upward movement of the carriage while allowing further movement of the slide 193 with the result that a bell-crank 210, links 212, and lever 208 are operated to produce horizontal movement of an operating-slide for the jaws 183, 183<SP>1