Process and apparatus for bending glass sheets

摘要

In a method for bending heat-softened glass sheets by sandwiching between complementary concave and convex glass shaping members movable towards and away from each other and between which the glass sheet is suspended, at least one of the shaping members moves upwardly at the same time as it moves inwardly towards the other shaping member. Carriages 12 are moved by driving rolls 10 of a conveyer 11 through a tunnel-like furnace 13, Fig. 1, and carry glass sheets G through the furnace 13 to a glass shaping station 14 and thence to a quenching station (not shown) where they are subjected to jets of cool air in the usual manner. The carriages 12 are composed of cast iron alloy and comprise an upper beam 15 that rides on the rolls 10 and a lower beam 16 interconnected by a pair of connecting rods 17, Fig. 2. Each glass sheet G is gripped at two spaced regions along its upper edge by a pair of steel alloy glass gripping tongs 18 suspended from each beam 16. When each heat softened glass sheet G reaches the shaping station 14 it is suspended between shaping members 20, 24 composed of heat resistant material such as stainless steel and having their shaping surfaces 21, 25 covered with fibre glass or asbestos. The shaping members 20, 24 are mounted on pistons 23, 28 with a slight upward tilt which are movable in cylinders 30, 31 rigidly secured at 14. Notched out portions 29 are provided to allow clearance for the glass gripping ends 19 of the tongs 18. In place of the tongs 18, wires or refractory blocks may be used to support the glass sheet G. In another embodiment, Fig. 4, the shaping members 20, 24 are tilted relative to the pistons 23, 28 such that the uppermost portions of the shaping surfaces 21, 25 are substantially tangent to vertical planes. In further embodiments, as shown for example in Figs. 5, 7, 9, one of the shaping members 20, 24 is first moved into contact with the glass sheet G so as to position the sheet in a predetermined manner and the other shaping member is then moved into contact with the other surface of the glass sheet while it is thus supported. Methods for controlling the relative timing of the movement of the members 20, 24 are indicated. The invention may be used either for producing simple bends in glass sheets about a horizontal axis or compound bends about more than one axis including one having a horizontal component. Specifications 960,515 and 960,516 are referred to.