Patent GB-464744-A (GB)
Title: Improvements in and relating to machines for the manufacture of electric lamps and the like
IPC: H01J5/42
Filed: 1936-09-05
Abstract: 464,744. Uniting metal to glass by heat. BRITISH THOMSON - HOUSTON CO., Ltd. Sept. 5, 1936, No. 24324. Convention date, Sept. 6, 1935. [Class 36] A machine for attaching a glass exhausting tube to a metal part of an electric incandescent lamp or similar article comprises a movable carrier with a series of heads each comprising members for gripping an exhausting tube and a holder for the part to which the tube is to be sealed, and burners on the heads for heating the parts to be sealed together, means being provided for moving the carrier whereby cams become operative to move the tube holders successively to bring the ends of the tubes against the parts to which they are to be sealed and effect the sealing. In the example, the machine is used for sealing glass exhausting tubes 15 to metal discs 12 of the kind forming part of the lamp described in Specification 452,191. Preferably, the movable carrier comprises a turret 16 mounted on an intermittently rotating sleeve 17 on a vertical shaft 10. Six heads are provided each comprising a pair of jaws 13, 14 which hold a glass tube 15 above a metal disc 12 located within a recess 11<1> in a plate 11 attached to the turret 16. The jaw 13 is pivoted in a recess in jaw 14 and movable relatively thereto against the pull of a spring 39. At position B, Fig. 1, a cam arm 41 bearing on a cam track 42 causes the jaws to be opened to enable an exhausting tube 15 to be inserted therein, the vertical position of the tube being gauged by its lower end bearing upon an arm 20 on a lever 21 controlled by a cam track 23. The jaws close between positions B and C and the disc 12 is engaged by the end of a holding-down lever 44 actuated by a spring 47 when the inner end of the lever is allowed to rise by movement of a vertical rod 46 controlled by a stationary cam 50 bearing on its upper end. At position C the lever 21 is moved from the lower end of the tube 15, and at position D burners 52, 53 mounted above the disc 12, and a burner 54 mounted below it, are lighted by stationary burners 55, 56, the upper pair being directed into the indentation 131 of the disc 12, while the lower burner is directed on the bottom of the indentation. When the centre of the disc is heated the glass tube 15 is moved downwardly towards it, the lower end of the tube being thus carried through the fires 52, 53 and heated so that it is sealed to the disc 12 when brought into engagement therewith. Preferably, the tube 15 is pulled upwardly again for a short distance to stretch it and form a contraction, as shown in Fig. 2. At position E the outer end of the lever 44 is lifted off the disc 12 by the cam 50 engaging the upper end of the rod 46. Simultaneously, the jaws 13, 14 are opened and the disc 12 with the tube 15 sealed thereto is then removed from the machine. Between positions E and F the fires are extinguished. The gas and air mixture is fed to the upper burners 52, 53 by means of a rotary valve comprising a stationary lower portion 75 held in position by studs 82 and connected to a supply pipe 77, the rotary upper portion 72 being provided with ports which connect with a passage 76 in the lower portion and convey the mixture through a passage 73 and nipple 71 to a valve 58 controlling the supply to the burners 52, 53. The valve 58 comprises a vertically reciprocating rod 61 which is cam operated and provided with a transverse orifice adapted to make intermittent connection to a manifold 57 carrying the burners, The lower burner 54 is mounted on the upper half 72 of the rotary valve and receives gases from a pipe 78 through passages 79, 80.