Patent GB-734263-A (GB)
Title: Improvements in and relating to apparatus for shaping filament mounts
IPC: H01K3/10
Filed: 1951-03-27
Abstract: 734,263. Shaping filament mounts for electric lamps. BRITISH THOMSON-HOUSTON CO., Ltd. March 27, 1951 [March 31, 1950], No. 7080/51. Class 39 (2). The leading-in wires and filament-supporting wires of a filament mount, comprising a stem with the leading-in wires and supporting-wires extending therefrom, are reformed and relocated by apparatus which decreases the radial distance between the axis of the mount and the free end of a support wire or a leading-in wire supporting the filament by displacing at least a portion of the wire angularly about the axis of the mount. The apparatus comprises an intermittently rotating turret or carrier 3 for advancing a mount to a succession of work stations A, B, C and D, Fig. 1, at which devices 15, 20-22, permanently located at those stations, bend and reform the wires from the arrangement shown in Fig. 2a into a sequence of shapes indicated respectively at b, c, d and e, the final form permitting the mount to be used in small, low-wattage, bulbs. The work stations A ... D are mounted on a stationary table 4 located in a plane below the course of travel of the work-carrying heads 2 of the turret 3. At station A the ends of the leading- in wires 8, 9 are bent closer towards each other by two anvils 16, 17, Fig. 2b, which are moved inwardly towards a stationary intermediate anvil 18, causing the ends of the wires to takeup positions such that the filament 14 is pulled taut around its supporting-wires 11-13. At station B the outer supporting-wires 11 and 13 are bent around towards the leading-in wires 8, 9 by the re-positioning device 20, Figs. 1 and 3, which is largely covered by the turret 3, and comprises three notched fingers 26-27. Finger 25 is mounted on an extension 34 of a lever 28 that is pivoted at 30 and provided with an offset arm 39 which is held in engagement with an operating-roller 33 by a tensioned spring 32. Finger 27 is similarly mounted on an extension 35 of a lever 29 which has an offset extension 36 carrying the finger 26, the latter being between fingers 25 and 27 and somewhat behind them. The operating-rollers 33 are carried by a block 37 at the upper end of a vertical operating-rod 38, so that when the latter is moved upwardly the contraction of the springs 32 tilts the levers 28, 29 and the fingers 25, 27 swing into engagement with the midportions of the supporting wires 11 and 13, which bend adjacent to the arbor 10. The notches in the ends of the fingers 25 and 27 are so arranged that the wires 11 and 13 are given an inward re-arrangement simultaneously with the other movement. The intermediate finger 26 engages the supporting wire 12 towards the completion of the movement of fingers 25 and 27 and operates to hold the wire 12 against bending while the wires 11 and 13 are being bent. The fingers are swung away from the wires on the return downward movement of the rod 38. At the work station C the device 21 operates to reform the leading-in wires 8, 9 and reduce the lateral spread or overall width of the mount in their plane by bringing the filamentcarrying ends of the leading-in wires closer to the stem tube 6 and arbor 10, as shown at d, Fig. 2. The mount is advanced to station C at a moment when the reforming device 21 at that station is tilted backward to an inoperative position.- The device 21 comprises a pair of jaws 53, 54, Fig. 4, which advance substantially radially inwardly towards the wires 8, 9 and, while the bent intermediate portions of the wires are engaged by the notched ends of a stationary finger 93 mounted above the jaws for the purpose of preventing upward movement of the wires, a pair of oppositely directed jaws 48, 49 are moved laterally inward and provide abutments against which the wires 8, 9 are pressed by the jaws 53, 54. The two pairs of jaws, still gripping the wires 8, 9, are next given an upward movement by corresponding movement of a horizontal platform 52 within which they are mounted, and the wires are re-bent until the ends holding the filament are placed directly opposite the button on the end of the arbor 10. The platform 52 is moved vertically by a rod 96 which is operated by a cam on a shaft below the table 4, the extent of movement being limited by an adjustable stop-collar 97 on the upper end of a guide column 58, any excess movement being taken up by a compression spring in the coupling at the lower end of the operating-rod 96. Operation of the jaws 48, 49 and 53, 54 is effected by mounting them upon slides 50, 51 and 55, 56 respectively, which are engaged by vertical cams 72, 73 and 74, 75, a roller 76 being interposed in each instance. The vertical cams are mounted on a lower platform 82 which is guided upon columns 57, 58 and raised and lowered by a vertical rod 87 controlled by a cam below the table 4. The vertical cams 72, 73 have cut-away portions 72<SP>1</SP>, 73<SP>1</SP> and, with the platform 82 in the lower position, as shown, the wide upper ends of the cams engage their associated rollers 76 to hold the slides in their outward positions, thereby holding the jaws 48, 49 inoperative and compressing springs 77 within the respective slides. The springs cause the jaws to move inwardly when the platform 82 is lifted. The jaws 53, 54 are controlled similarly by the vertical cams 74, 75 which are, however, profiled to a different extent in comparison with the cams 72, 73. Tilting of the device 21 to and from the operative position is effected by mounting the two columns 57, 58 in a yoke 59 which can be pivoted about studs 60, 61 on the opposite arms of a stationary bracket 62 under the control of cam-operated means connected to the lower end of column 58 which extends downwardly through the table 4. At work station D the final reduction of the spread of the mount is effected by the reformation of the intermediate supporting wire 12 by the device 22, Fig. 9, which is tipped back from its operative position while the mount is being brought before it. The device 22 is very similar to the device 21 at station C, and comprises an upper platform 107 which is slidable upon two columns 108, 109 held by a yoke 110 carried by horizontal pivots 111, 112 at opposite ends of a bracket 113, the rocking movement being effected by means acting on the lower end of column 109 below the table 4. The wire reforming device comprises a clamping jaw 122 at the end of a slide 123, and a co-operating jaw 124 extending laterally at the end of a, lever 125, movement of these jaws being controlled by vertical cams 128, 129 co-operating with rollers 130, 131 on the adjacent outer ends of the slide 123 and lever 125 respectively. Lateral opening movement of the lever 125 is effected in opposition to a blade spring 134 which presses a slidable plunger 133 against the lever. The initial vertical movement of a platform 132 carrying the vertical cams causes the jaw 124 to be positioned beneath the arched portion of the filamentsupporting wire 12, Fig. 10, whereupon the jaw 122 is operated to force the wire against the jaw 124, lateral slipping of the wire being prevented by a notched guide 135 at the end of the jaw 122. Following the re-bending and gripping of the filament-supporting wire 12 between the jaws 122, 124, an upward movement is given to both jaws to wrap the intermediate portion of the wire 12 over the top of the jaw 124 and re-locate the looped filamentholding end of the wire at a position opposite the end of the arbor 10, as shown at Fig. 2e. Take-up means controlled by an adjustment screw 149 and spring 148 are provided to prevent excessive tension being applied to the wire 12. Specification 390,807 is referred to.