GB363916A - Improvements in the manufacture of electric incandescent lamp bulbs or like hollow glass vessels - Google Patents

Abstract

363,916. Glass manufacture. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London. - (Assignees of Patent-Treuhand Ges. fur Elektrische Gl³hlampen; 11, Ehrenbergstrasse, Berlin.) March 17,. 1931, No. 8205. Convention date, May 22, 1930. [Class 56.] Forming articles from tubing. - Relates to a machine for making small electric lamp bulbs or other hollow articles from glass tubing, and particularly to a machine of the type in which an horizontal frame, on which vertical heads for holding glass tubes are mounted, is rotated step by step to present the tubes to gas burners and to various operating-devices. According to the invention, two heads are provided for each tube, one arranged vertically above the other, the lower head being movable vertically by a stationary cam, and moulding-tongs are provided for enabling the tubes to be shaped by pressure instead of by blowing. The machine comprises two spiders 3, 4 secured to a vertical spindle 2 which is rotated step by step by suitable means. Bushes 9, 10 are journalled in the arms of the spiders 3, 4 respectively, and in each bush is fitted the sleeve 11, 12 of an upper or lower head, respectively. These heads are rotated in unison with one another by a vertical shaft 13 connected with the driving-system. The sleeve 11 of each upper head has a conical lower end 22 in which inclined clamping-bolts 23 slide. These bolts hold a glass tube 24 which is inserted into the head from above, and they are controlled by a conical cap 27 which encloses the cone 22 and the bolts 23 and is forced downwards by a spring 28. The lower end 50 of the cap raises the bolts and releases the tube 23 when the cap is raised against the pressure of the spring 28. The lower head is similarly constructed, but while the sleeve 11 of the upper head is rigidly connected to the bush 9, the sleeve 12 of the lower head can be moved vertically in the bush 10. The lower end 34 of the sleeve 12 slides on a fixed cam 33. When any of the heads is in the position A, Fig. 1, a positioning rod 35, Fig. 2, is moved upwards and passes through an aperture 36 in the cam 33 into the bore of the lower head until it bears against the end of the glass tube 24. A nipple 37 which is formed on the end of the glass tube enters an aperture 38 in the rod 35. The caps 27 of the two heads are then forced apart by two levers 43 which are moved inwards to engage the caps. The separation of the caps causes the bolts 23 to release the glass tube and leave it standing in the rod 35. The rod now drops a short distance and the levers 43 are moved away from the heads, so that the glass tube is again clamped by the bolts 23. The rod 35 is then lowered and the head is moved in succession to positions B, C. D. In these positions, burners 51, 52, 53 heat and soften the section of the glass tube lying between the upper and lower heads. At position E, moulding jaws 64, Figs. 1 and 4, are moved inwards and are closed on the glass tube, so that they constrict and shape the softened glass and form a portion 67, Fig. 4, of smaller diameter having two attached shoulders 68. In subsequent positions, F, G, burners 69, 70, heat the narrowed section 67 of the tube, and the sleeve 12 is lowered by the cam 33 so that the section 67 is again constricted at its middle. The construction is further drawn out at position G, and is severed by a needle burner at position H, a blade 77 being provided to ensure the separation of the two parts of the glass tube. Finally, the shaped portion of the tube so separated is cooled in position J and is released by the head in position K.