Patent GB-724890-A (GB)
Title: Improvements in and relating to electric lamp making machinery
IPC: H01J9/28
Filed: 1953-10-30
Abstract: 724,890. Making electric lamps. BRITISH THOMSON-HOUSTON CO.,-Ltd. Oct. 30, 1953 [Oct. 30, 1952], No. 30062/53. Class 39 (2). Apparatus for trimming the end of, a side leading-in wire projecting radially from between the lower edge of the cap and the neck of the bulb of an electric lamp comprises means for tensioning the wire at an upward inclination, and a cutter mounted above the wire and hingedly suspended so that when its support is lowered the cutter is swung inwardly in a direction radial to the bulb and the wire is severed close to the edge of the cap. In the example the bulb 3 is carried neck upwardly in a rotary turret machine of known type with its lower end engaged by a cup 8 mounted on a spring-pressed rod 7, and the lower part of the cap gripped between jaws 14, 15. The wire-trimming apparatus, which is mounted adjacent to the indexing path of the turret is camoperated from the machine drive, so that the wire 20 is gripped between jaws 21, 22, tensioned by upward movement of the jaws, and then severed by the descending cutter 40 during-the interval at which the bulb is halted at the trimming station. The wire-gripping jaws are pivoted 23 on a pedestal 24 mounted on a rigid support 25, the lower jaw 22 having a rearward extension 31 linked to a vertical rod 32 to which is secured a slotted sleeve 34 supporting a pair of tension springs 35 and enclosing the upper end of a rod 33 provided with a pin 37 extending through the slot 38 and connected to the springs, whereby a lost motion is provided and permits over-travel of the lower rod part after jaw 22 has reached the upper limit of its travel. This upper limit is determined by a stop bolt 26 bearing upon the upper jaw 21, which has pivoting lugs astride the lower jaw and is pulled towards the latter by a tensioned spring 29, the downward movement being limited by a stop formed by a headed bolt 28. In operation the jaws are opened to receive the wire 20 therebetween, as shown in Fig. 1, whereupon the-vertical rod 33 is reciprocated downwardly, so that the wire is first gripped between the jaws and then pulled upwardly by them into the position for cutting, Fig. 2. The cutter 40, which has a bevelled knife edge, preferably curved to the radius of the lamp cap, is hinged at 55 to an intermediate swivel member 56 pivoted at 57 to the lower edge of a slide bar 41, the hinge 55 allowing the cutter to swing in a plane radial to the bulb, and the pivot 57 permitting it to swing from the vertical in the direction of movement of the turret, but not in the opposite direction. A spiral spring 61 tends to maintain the cutter vertical. The slide bar 41, which moves within vertical guides on a block 44, is normally pulled upwards by a tensioned spring 45, its downward, cutting-movement, being effected by downward movement of a horizontal arm 47 engaging within a slot 48 in the upper end of the slide bar 41. The horizontal arm 47 is offset from a vertical rod 46 which is secured at its lower end 'to the rod 33 by a welded plate 49, the arrangement being such that, after the wire has been gripped and tensioned and further movement of the jaws prevented by the stop bolt 26, the continued downward movement of the lower rod part 33 is taken up by the lost motion device 34-38. The auxiliary rod 46, however; continues to move down, causing the cutter 40 to be lowered. The knife edge is thereby brought into contact with the inclined lead wire 20 at a point intermediate the gripping jaws and the lower edge of the lamp cap, and begins to swing in towards the cap and follows the wire to the point where it meets the said lower edge. At this point the wire is sheared off, leaving substantially no stub protruding. Specification 247,923, [Class 39 (ii)], is referred to.