Patent GB-385537-A (GB)
Title: Process of and apparatus for producing tipless and stemless electric incandescent lamps
IPC: H01K3/00
Filed: 1932-06-24
Abstract: 385,537. Making electric incandescent lamps. PRÍSCHOLDT, 0., Oberweissbach, Thuringia, Germany. June 24, 1932, No. 17911. [Class 39 (ii).] In a process for producing tipless and stemless electric incandescent lamps, the lamp bulbs are held neck downwardly within grippers in spaced relationship from a holder within which the exhaust tube is so disposed that its upper end extends within the neck of the bulb for about one or two mm., the filament being supported by the same holder with its leading-in wires adjacent to the exhaust tube, so that when the jets or burners act upon the lower edge of the neck of the bulb the neck contracts as it becomes plastic and flows upon the upper end of the exhaust tube to seal the leading-in wires. The passage through the exhaust tube is kept clear during the process by the rising and falling movement of a pricker therein. The apparatus comprises a hand-wheel or circular table 11, Figs. 3 and 4, mounted on an axial shaft 26 and carrying near its outer edge four vertical spindles 40 which are rotatable upon their own axes. A power-driven pulley 46 mounted beneath the machine bed or table 55 drives, through belt-connected pulleys 47, 37 and 48, 23 respectively, a pulley 51 and a cam 24. The pulley 51 is connected through a driving belt 53 to pulleys 52 mounted upon the shafts 40, the belt being held away from a pulley 52, however, by pulleys 54, when the shaft 40 on which it is mounted is at station A, Fig. 3. During the rotary movement of the table 11 the shafts 40 are moved vertically within their journals by a ramp 10 which engages a flange 12 on their lower ends, the shafts being in their lowest position when at station A and in their highest position at station C, the'height being intermediate when at stations B, D. The bulb 1, Fig. 6, is supported by the inturned ends 70 of gripper levers 44 which are mounted above each shaft 40 upon an arm 60, Fig. 4, mounted adjustably upon a rod 13 carried by an arm 58 which rotates with the shaft 40 while allowing the latter to move vertically within it. The lamp parts are inserted at position A, the grippers 44 being opened to receive the bulb by the manual lifting of a collar 27 at their upper ends of pivotal connection, and the bulb is held by spring pressure exerted by a concave head 31. The exhaust tube 4 is inserted in a recess at the upper end of the shaft 40, and the leading-in wires 3 are held within adjacent recesses by the upper ends of spring-pressed levers 36 mounted on the shaft. As the parts are carried round to station B the exhaust tube and filament are lifted slightly, and at station B the parts are preheated. At station C the sealing-in is effected and on passing to station D the lowering of the shaft 40 causes the exhaust tube and plastic part of the bulb sealed thereto to be drawn out and reduced in diameter until the seal assumes the form shown in Fig. 2, with a comparatively short length of leading-in wire sealed into the glass. During the movement of the shaft 40 from station C to station D the levers 36 which grip the leading-in wires are opened by pressure exerted on their lower ends by arms 61, Fig. 4, on a yoked member 14 slidably mounted on the rod 13, the member 14 being held normally in its upper and inoperative position by a shoulder 17 on the rod 13 engaging a detent 19 on a lever 63 which is released when its lower end strikes a member 73, Fig. 3, adjacent to the rotating table. The pricker 41, Fig. 6, which keeps the exhaust tube clear during the sealing is mounted at the upper end of a rod 21 resting upon a vertically movable plunger 22 controlled by the cam 24.