Patent GB-668308-A (GB)
Title: Improvements relating to apparatus for the manufacture of bases for electron discharge devices and the like
Inventor: BROAD DONALD ANTHONY GIFFORD
IPC: H01J9/32
Filed: 1949-04-08
Abstract: 668,308. Making bases for electron discharge devices &c. ELECTRIC & MUSICAL INDUSTRIES, Ltd. April 11, 1950 [April 8, 1949], No. 9555/49. Class 56. Apparatus for the manufacture of bases for electron discharge tubes, electric lamps and the like comprises relatively movable dies 3, 4 and means for mounting an assembly of leading-in wires and glass between the dies comprising supports 7, 17, which project from the dies, for the ends of the leading-in wires, the supports and dies being relatively movable so that the dies can be suitably spaced apart, with the supports projecting therefrom, so as to enable the glass to be heated without overheating the dies and so that the dies can be moved to a closed position to shape'the glass, in which position the supports are retracted relatively to the dies. The dies 3, 4 are supported in cylinders 1, 2 which are axially aligned, adapted to be rotated in the same direction, and relatively longitudinally movable. The dies are located by the mating of flange 5 on die 3 and the recess 6 on die 4. A plurality of hollow rods 7 mounted and longitudinally movable in die 3 contain pins 8 which are pressed outwardly by springs 9, and are secured by screws 10 to a disc 11 having a rod 12 which projects through a disc 13 secured to the cylinder 1 by a flange 14. A compression spring 15 between discs 11 and 13 normally urges disc 11 to a position in which rods 7 project from the die. Short lengths 16 of lead-in wires are received in openings in the ends of rods 7. A corresponding number of hollow rods 17 project through and are longitudinally movable in die 4 and contain pins 18, which normally bear at the outer ends against the ends of the rods 17 and at the other end project through the rods to be secured to a disc 19. The outer ends of the rods 17 have openings to receive the wires 16, while the other ends are secured to a disc 20 having a rod 21 projecting through a disc 22. The disc 22 is secured to the cylinder 2 by a flange 23 which is stepped to provide stops 24, 25. A collar 26 is secured on the rod 21 and a compression spring 27 between collar 26 and disc 19 presses the disc 19 and pins 18 towards the outer ends of rods 17. A compression spring 28 between collar 26 and disc 22 serves to cause rods 17 normally to project from die 4. Assuming cylinder 1 to be fixed and cylinder 2 movable, operation is as follows: the cylinders are moved apart, the wires inserted in the openings in rods 7 or 17 and inner and outer rings 29, 30 of glass, e.g. glass tubing of high melting point, placed within and around the wires. Cylinder 2 is moved towards cylinder 1 and the other ends of the wires inserted in the other die, as in Fig. 1. Cylinders 1 and 2 are rotated and the glass rings heated, e.g. by gas flame, until they form an annulus adhering to the wires. Cylinder 2 is then moved to close the dies. Initially rods 7 and 17 do not move relatively to each other but the dies move relatively to the rods compressing springs 15, and 28, this relative movement being prevented when disc 11 bears against stop 14 and disc 20 against stop 25. The relative position of rods and dies is now as in Fig. 2. On further closing of the dies, wires 16 cause pins 8 and 18 to move away from the apertured ends-of rods .7, and 17 against the action of springs 9, 27. When the dies have closed, Fig. 2, disc 19 bears against stop 24 limiting the movement of the pins, and the softened glass is pressed to shape, bosses 31 being formed in the recesses in the dies formed by the movement of the rods 7, 17. The cylinders &c. may be vertically mounted.