GB718005A - Improvements in and relating to crack-off devices for removing excess exhaust tube from lamps, radio tubes and the like - Google Patents

Abstract

718,005. Making electric lamps &c. BRITISH THOMSON-HOUSTON CO., Ltd. Oct. 28, 1952, [Oct. 30, 1951.] No. 27071/52. Class 39 (2). Apparatus for cracking off the excess end portion of a vitreous exhaust tube extending from a mount for an electric lamp, radio tube, or the like, comprises a mount holder 12, Fig. 3, with a portion 15 arranged to provide a rest for the flared stem tube 5 of an inverted mount 3 and a second portion 39 spaced above the portion 15, so that when the holder is moved and carries a mount laterally to bring a notched or scored portion of its exhausting tube 4, Fig. 2, against a stationary stop finger 38, the mount is first tilted in its holder so that the flare 11 of the stem tube is engaged and restrained by the portion 39 of the holder, whereupon further movement of the holder relative to the stop finger 38 produces a strain in the exhaust tube sufficient to break it at the notch 10. Fig. 1 shows a part of the conveyer 1 of mount-making apparatus of the kind disclosed in Specification 564,702, [Group XL], and comprising work stations A and B located adjacent to another conveyer 2 of the endless chain type provided with a series of work holders 12 and pairs of jaws 13, 14 which take over the inverted mounts and grip the exhaust tube 4 thereof after the latter has been scored in passing a sharp edged metal disc 7 driven by a high speed motor 9 located adjacent to the work station A. The conveyer 2 is mounted upon a support which is reciprocated bodily to and from a position adjacent to work station B, the timing being such that a mount is released from conveyer 1 when a work holder of conveyer 2 is positioned to receive it. In the following bodily movement of conveyer 2 away from work station B a pivoted pawl-carrying arm 20 is operated by a link 23 to turn a shaft 19 carrying the chain-driving sprocket 16, whereby the work-carrying heads 12 are indexed one step with the chain 18 and an empty head 12 is advanced to the receiving position. The two straight runs of the conveyer chain are guided by rails 24, 25 on opposite sides of each run, so that the inward parts of the flare supports 15 slide along the rails, Fig. 3. The breaking or cracking-off operation is effected when a head carrying a mount arrives at station C at the end of the conveyer remote from the loading station B, so that bodily movement of the conveyer towards the left causes the upper end of the exhaust tube 4 to strike the stop finger 38 and break at the scored or notched part 10. To prevent the mount from being jarred out of the holder 12 by the impact, a stationary guard 44 is mounted adjacent to the stem tube. The abutment finger 38 is mounted on a hinge pin 45 near the end of a rigid supporting arm 46 and normally rests on the end portion 47 of the arm; alternatively it may be rendered inoperative by tilting it rearwardly upon the arm 46.