GB1341873A - Shaping glass sheets - Google Patents

Abstract

1341873 Shaping glass sheets PPG INDUSTRIES Inc 19 April 1971 [10 March 1970 4 Dec 1970] 23579/71 Heading C1M Glass sheets G, Fig. 1, are heated to their deformation temperature in a furnace 22 having heaters 23 and driven conveyer rolls 21 passing the sheets to a bending station 24, whereafter the shaped sheets are passed to a cooling station 26 having driven conveyer rolls 27 and cooling nozzles 29, the sheets G being shaped in the station 24 without interrupting their passage therethrough by means of complementarily-shaped moulds each comprising a set of shaped rolls at least one of which sets is movable from a retracted position to a glass-engaging position. In one embodiment, concave rolls 34, Fig. 4, are mounted on shafts 23 rotatably mounted on a fixed housing 31, there being a respective complementary convex roll 46 above each roll 34, rolls 46 being mounted on shafts 47 rotatable in a housing 41 also supporting conveyer rolls 42, the housing 41 being raised and lowered by a piston and cylinder device 45 assisted by counterweights 52. To allow compound bending of the glass sheets, the shafts 33, 47 are individually vertically adjustable. Each roll 34 or 46 is divided into segments 34a-34f, 46a-46f respectively, at least one segment, and preferably two symmetrical segments of each roll being keyed to its shaft to rotate with a peripheral speed equal to that of conveyer rolls 21, 42, 27, the other segments being free-running. The shafts 33, 47 and rolls 42 are all driven, via sprockets and chains, by one motor 30, a movable sprocket 81, Fig. 3, on a weighted lever 82 preventing slippage. The apparatus includes position-sensors and timers which operate so that the shaping rolls are held in engagement with the glass sheet for a period of time approximately equal to the time of a single revolution of the shafts 33, 47, to avoid introducing distortion resulting from changing the shape imparted by different rolls to the same increment of glass length. In a further embodiment, Figs. 11-19 (not shown), the conveyer rolls in the bending station are stationary vertically and level with the conveyer rolls in the furnace and cooler, and an upper and a lower set of shaping rolls are both moved vertically by pistons to engage a glass sheet, the conveyer rolls in the furnace being driven by a first motor at a slower speed than the conveyer rolls in the bending and cooling station s which, together with the shaping rolls, are all driven by a second motor. In another embodiments, rolls of an upper set of shaping rolls are concave and those of a lower set are convex. The conveyer rolls 21 in the furnace 22 are of stainless steel but conveyer rolls in the bending 24 and cooling section 26 are covered with fibre glass sleeves. Alternatively in the bending section, stainless steel maybe used and in the cooling section, mild steel. A gas heater may be used for conveying the glass sheets.