Patent GB-217519-A (GB)
Title: Improvements in or relating to machines for manufacturing stems for electric lamps
IPC: H01K3/10
Filed: 1923-12-29
Abstract: 217,519. Naamlooze Vennootschap Philips' Gloeilampenfabrieken. July 19, 1923, [Convention date]. Making lamps.-In a stemmaking machine of the kind comprising a rotary table with a number of carriers for holding the stem tube 25, Fig. 14, leading-in wires 28, 29 within this tube, a glass rod 26 in alignment with the tube, and if necessary an exhaust tube 27 within the stem tube, the carriers are disposed tangentially in relation to their direction of travel around the axis of the table. The assembled stem parts are, in known manner, heated and pressed together and an aperture 123 formed, as shown in Fig. 15, by compressed air to enable the lamp bulb to be exhausted at a later stage. The rotary table comprises two rings 1, 2 in which the carriers are pivoted. Each carrier comprises a pair of fingers 37, 38 fixed to vertical rods 20, 21, Fig. 5, rotatably mounted in the. rings 1, 2, a spring 43 causing the fingers to grip an exhaust tube 27. Fingers 22, 23 rotatable about the rods 20, 21 are adapted to grip the stem tube 25 under the acion of a spring 36. The glass rod 26 is placed on a support 57 and is held centrally in a bore in a block 55 in which it is clamped by a projection 62 on a finger 61, Figs. 5 and 8, controlled by a spring 65. The leading-in wires are held in holes in the block 55 by fingers 70, 71 mounted on rods 67, 68 controlled by a spring 69, and their upper ends are pressed against the exhaust tube by springs 74 connected to the rods 67, 68. In two successive positions of the rotary table the parts are heated, and in the third position they are pinched together by jaws 16, 17, pivoted at 153, Fig. 2, and adapted to, be closed slowly and at decreasing speed by a lever 160 operated from a treadle 180, Fig. 13, through links 173, 176 so adjusted that they reach their dead centre when the jaws are just closed. A pivoted hook 14, Fig. 13, which locks the rotary table in the several stationary positions, is operated from the treadle 180 through a catch 198 so arranged that the table can only be unlocked while the treadle is moving upwards. The presser on the jaw 17 is mounted on a member 155 pivoted to the jaw and adjustable in relation to the other jaw bv a set-screw 159. At the next position of the table the aperture 123 is blown by an air-jet 118, while a jet 121 maintains air pressure in the space 122 between the exhaust and stem tubes. At the next step a mark is impressed in the pinched part of the stem by jaws constructed and operating like and in unison with the pinching- jaws 16, 17. In passing to the. next position, the lower ends of the rods 20, 21 ride over fixed cams which lift them against the action of springs 45, 46 and so stretch the hot parts of the exhaust tube and of the adjacent seal. In passing to the next position, a finger 217, Fig. 5, rides on a fixed cam and turns the rod 21 to release the exhaust tube from the fingers 37, 38, which are then retracted to their normal level. In the final position all the grippers of the carrier are opened by means of handles 35, 42, 64. the finished stem is removed, and a new set of parts inserted. Specification 180,125 is referred to.