GB715916A - Improvements in or relating to apparatus for manufacturing voltage breakdown devices - Google Patents

Abstract

715,916. Cold-cathode tubes. GENERAL ELECTRIC CO., Ltd. March 4, 1953 [March 20; 1952], No. 7232/52. Addition to 715,685. Class 39(1) An apparatus, Fig. 3, for the manufacture of voltage breakdown devices, Fig: 1, of the kind described in the parent Specification and comprising a glass tube 1 closed at each end by a dished disc' 2 of an iron-nickel-cobalt alloy and filled with argon at a pressure of less than 100 mm. of mercury, comprises two intersecting glass tubes. A metal delivery channel 4 for the supply of the assemblies to be sealed is held in position by plates 22 and 23 and a leaf spring 24 in a portion 3 of one tube, and a portion 6 of the other tube houses carrying means for lifting the assemblies into a sealing head formed by a portion 5 of the said other tube which is surrounded by an eddy current heating coil 40. After sealing, the assemblies are released into a portion 7 of the first tube. Detachable caps 8 and 9 are attached to the tube 3, 7 by greased ground-flange joints 10 and 11, and a side tube 12 is provided for evacuating and filling the enclosure. The tubes are supported by clamps 13 and 14 with the tube 3, 7 inclined to the horizontal to ensure gravity feed of the assemblies along the delivery channel 4 or alternatively a spring may be provided to urge the assemblies along the delivery channel. The channel 4, Fig. 4. is of rectangular cross-section with an open top and has one open end 15 projecting into the cap 8 and the other end closed to form a stop 16. The base of the channel is continued by a platform 19 which together with the side.walls of the channel is provided with slots 20 and 21. The carrying means, Fig. 5, comprises tweezers 17 and 18 pivotally supported on a mild steel head 25 and biased together by a spring 33 against a stop 34. A soft iron armature 26 carried by the head 25 co-operates with the pole-pieces 27 and 28 of a magnet 29 carried on a collar 30 so that by sliding the collar along the exterior of the tube, the tweezers can be moved axially along the tube. The tweezers are provided near their free ends with curved prongs 38 and 39 forming supports for the assemblies, and are formed with shoulders 34<SP>1</SP> and 35<SP>1</SP> adapted to engage within the dished parts of the discs 2 and sloping ramps 36<SP>1</SP> and 37<SP>1</SP> enabling the shoulders to slide out of the dished parts against the bias of the spring 33 on retraction of the tweezers. The tweezer assembly is supported at one end by the engagement of the armature 26 with the inner surface of the tube and at the other end by the engagement of the tweezers with the slots 20 and 21 in the delivery channel 4.