GB910186A - Improvements in or relating to methods of manufacturing glassware - Google Patents

Abstract

910,186. Welding glass. PHILIPS ELECTRICAL INDUSTRIES Ltd. Oct. 31, 1958 [Nov. 4, 1957], No. 35024/58. Class 56. In the sealing together of two glass objects with peripheral edges of similar but non-circular shape, a plurality of burners are positioned between the adjacent end surfaces of the edges so that at least a number of oppositely directed flames emerging from the burners are directed to the end surfaces to be sealed and during this heating, the burners are moved relatively to the end surfaces and displaced along their whole peripheries and the degree of heating is controlled by regulating the supply of fuel to the burners according to the amount of heat required at different parts of the peripheries, the burners being removed after sufficient heating of the whole of the end surfaces and the objects moved towards each other to seal the end surfaces of their edges together. As shown, the gl; as window 12 for the bulb 74 of a television tube is positioned by holders 11 on a table 10 rotatably mounted by a shaft 13 in a frame 9 which is slidably supported by rods 7, 8 moving in bushes 5, 6 in the lower member 4 of a main frame 1-4 and the cone 24 of the bulb 74 is held by its neck 23 in a clamp 22 on a shaft 21 rotatably journalled in the upper member 3 of the main frame, both shafts 13 and 21 being rotated from a driving shaft 17 through chains 15 and 27. A cam disc 18, of similar shape to the periphery 19 of the window 12, is carried on the shaft 13. Each of the positions A-Q on the top 20 of the frame 9 may carry a burner 40, but several positions may be left vacant to facilitate insertion and removal of the window 12. Each burner 40 has apertures 40a at top and bottom to give flames 48 directed on to the end surfaces 46a, 47 of the cone 24 and window 12 and, for use after sealing, apertures 40b which give flames 49 directed towards the axis X-X of rotation. Each burner 40 is mounted on a carriage 37 and has up-and-down movement on a pin 36 passing through the carriage 37 to rest on a ring 45 which can be moved up and down through articulated junction pieces 46 secured to the frame 9. Each carriage 37 is mounted on a carrier 30 movable between guides 31, 32 towards the axis X-X and pressed by an air cylinder 35 mounted on the frame 9, the carriage 37 pivoting about the pin 36, which also passes through carrier 30, and having rollers 38, 39 which press against the cam disc 18 to maintain the burners 40 between the edges 46a, 47 during the heating thereof. Each burner 40 is slidably mounted on an angle piece 41 and is moved into and out of position between the edges 46a, 47 by an air cylinder 42. Oxygen and gas are supplied to apertures 40a through lines 55, 59; 62, 61 and joint line 50 and to apertures 40b through lines 56, 63; 65, 66 and joint line 51, the supply of oxygen passing through a valve cabinet 52 with mechanism regulated by cam-shaft 57 and gears 58, 29 from shaft 21 to regulate the burners as a function of their relative speed along the peripheries of non-circular objects. Initially the cone 24 and window 12, placed close together, are given a general heating by burners (not shown) and are then separated by lowering frame 9 and the burners 40 moved into position between the edges 46a, 47. Heating is continued through apertures 40a for several revolutions of the parts 12, 24 so that the edges are uniformly heated, the burners then retracted and the window 12 lifted to press against the cone 24 to form a seal 71 which will bulge both outside and in. The plate 45 is then lowered to bring the burners 40 with apertures 40b opposite the seal 71 which is reheated. The table 10 is then lowered slightly and the bulge outside removed by a smoothing roller 72 on a swinging arm 73 and that inside by compressed gas pressed in through neck 23 by a line 67, with clearance for discharge of excess gas. The flames of the burners, shown as being directly opposite, may be at slight angles to one another.