Patent GB-707399-A (GB)
Title: Improvements in and relating to apparatus for inserting filament support wires for incandescent lamps and the like
IPC: H01K3/10
Filed: 1951-02-21
Abstract: 707,399. Making electric incandescent lamps. BRITISH THOMSON-HOUSTON CO., Ltd. Feb. 21, 1951 [Feb. 25, 1950], No. 4225/51. Class 39 (2) In a lamp mount making machine of the kind including a turret or the like comprising a number of heads each adapted to support a lamp stem which is indexed past a number of work stations including one at which filament supporting wires are inserted into a plastic portion of the lamp stem, an inserting apparatus including means for holding spools of wire, severing the required lengths of wire therefrom, and inserting two or more such lengths into the plastic stem portion, is arranged to perform such operations when positioned at one side of the indexing path of the stems and to be movable to the other side of the path for replenishing, adjustment, and servicing. The stems 1, Fig. 2, carried in heads 5 around the periphery of a turret 6 are indexed to a workstation A at which the apparatus for inserting filament-supporting wires is mounted on a table 4 located in a plane below the path of the stems and movable vertically to and from an operative position, these movements being synchronized with the indexing movements of the turret, so that the table 4 is in a low position while a stem is entering the work station. The common driving means for the turret and wire-inserting apparatus, and the means for heating the glass arbor 3 of the stem to a plastic condition at work-stations preceding station A correspond to those described in Specification 390,807. The stems are each held in an inverted position between two pairs of jaws 10, 11 and 12, 13 mounted on a head 5, the jaws 10 and 12 being fixedly mounted at upper and lower ends respectively of a vertical supporting sleeve 15, whereas the jaws 11, 13 are pivoted to exert a gripping force under the action of a tensioned spring 18. The wire-inserting apparatus mounted on the table 4, which is below the plane of the turret, comprises three heads 24 carried by a platform 67 which is rotatable about a central axis 61, the heads 24 being arranged radially relative to the axis and at the same relative angular disposition as that required for the radial supporting wires 2, their location when in the operative position being within the indexing circle of the stems. The platform 67 is rotatable about its axis to bring the heads 24 to the outside of the aforesaid circle, and can be locked in one or the other position by a spring-loaded detent 92 at one end of a hand-lever 91. A warning-lamp which lights when the hand-lever 91 is not in locking position is controlled by a switch that is in the "off" position when the end of a screw 101 on lever 91 is withdrawn from a control button 102. Each head 24 of the wire-inserting apparatus comprises a spool 26 mounted on a bracket 30 clamped to a supporting standard 31, (shown detached in Fig. 6) the wire from the spool being guided along a groove in the top edge of an arm 36 extending from the bracket 30 and between jaws formed by the end of the arm 36 and a spring finger 37 attached thereto. Further towards its end the wire is gripped between the ends of jaws 27, 28, Fig. 3, which are pivoted on a horizontal pin 50 in a main horizontal slide 46 and associated with a subslide 44 which is movable within a channel in the main slide 46. Oppositely inclined cam slots on the sides of the sub-slide are each engaged by a roller 49 on one of the jaws 27, 28, so that forward movement of the sub-slide causes the jaws 27, 28 to turn about their pivot 50 and close upon the wire 25. Movement of the sub-slide 44 is effected by connecting its outer end by a short link to the upper end of a bell-crank lever 57 pivoted at 58 to the bracket 31, the other arm of the bell-crank having an end roller 63 which co-operates with a flanged head on a stud 64 carried by an arm of a spider 62. The spider has three such arms associated with and operating simultaneously upon the wire feeding apparatus of each of the three inserting heads 24, shown in Fig. 1, and is secured at the upper end of a vertical shaft 65 which is movable within a hollow shaft 66 by actuating cam 69, Fig. 4 (not shown) at its lower end. The platform 67 is secured by a coupling flange to the hollow shaft 66 and the latter is also adapted for vertical movement by a cam at its lower end. The arrangement is such that the spider 62 and platform 67 are moved towards their lower position while the stem is being indexed into position, and, during this movement the cam causes the flanged heads on the arms of the spider to bear upon the respective rollers 63 to swing the levers 57 clockwise, thereby moving the sub-slides inwardly to cause the jaws 27, 28 to grip the wires 25. During this initial movement the main slide is held against movement by the frictional pressure of a spring-pressed block 52 upon its upper surface, thereby holding the jaws 27, 28 against longitudinal movement until they have closed upon the wire, whereupon the main slide and the jaws move together with the sub-slide. The wire-inserting apparatus is next moved upwardly by the platform 67 being lifted by the cam associated with the sleeve 66, and the spider 62 is also lifted simultaneously so that the wire-inserting apparatus is halted. During the final upward movement the lengths of wire already advanced and held by the feed jaws are sheared from their spool supply by co-operating rotary cutters 39, 40, 'thereby forming the individual support wires 2. The shearing action is controlled by a fixed cam 111, Fig. 6, supported by an arm 114 on a post 113 mounted on a base ring 88, the cam being arranged to engage a pawl 110 and swing a lever 112 about a pivot pin 117, thereby effecting oppositely directed rotation of a coaxial shaft 119 and a sleeve mounting the cutters. During the upward travel of the inserting apparatus the softened lower end of the glass arbor 3 is flattened to form a button by an anvil 131, Fig. 3, mounted at the top of a bracket 97 on the platform 67 and aligned with the operative axis 61 so that it engages and pushes upward upon the end of the arbor, the anvil being shaped to form a symmetrical button. Upon the spider 62 and platform 67 reaching their upper limit of motion, the spider is again moved down, thereby effecting longitudinal motion of the jaws 27, 28 in a horizontal plane and plunging the support wires 2 end-first into the still somewhat plastic glass button. The jaws grip the wires sufficiently close to the end to avoid bending during insertion. Specification 301,047, [Class 39 (ii)], also is referred to.