Patent GB-1060893-A (GB)
Title: Method and apparatus for bending and tempering glass sheets
Inventor: OELKE WALDEMAR WERNER
IPC: C03B27/056
Filed: 1965-07-22
Abstract: A method of bending and tempering glass sheets as they are moved along a predetermined path through successive heating, bending and chilling areas, the sheets being supported on heated gases during movement through said heating area where they are brought to their softening temperature and on relatively cool gases during movement through said chilling area to temper the sheets, is characterized in that the forward movement of the sheets is interrupted in said bending area and while maintained stationary the sheets are pressed into the desired curvature between complemental shaping <PICT:1060893/C1/1> surfaces before they are passed into the chilling area.  Glass sheets S (Fig. 2, not shown) are fed into a heating area B on a conveyer 20. The heating area comprises a set of seven heating boxes 46 in side-by-side relationship. Hot gases are burnt within opposed chambers 52 (Fig. 7, not shown) of the boxes, the gases issuing through orifices 58 in the opposed faces 48 of the boxes. The faces 48 are made of a refractory material, e.g. 99.8% fused silica and have the orifices arranged in upwardly inclined rows separated by grooves by which the gases exhaust, with a greater density for orifices at the bottom than at the top.  Preferably the heating boxes are tilted at about 10 degrees from the vertical, the glass sheets being prevented from contacting the faces 48 by maintaining a sufficient gas pressure to form a gas cushion between sheet and face. By having a series of individual heating boxes 46 greater temperature control of the sheet can be achieved.  The heating boxes are so mounted as to be adjustable in the horizontal or vertical directions. The glass sheets are then moved on to another conveyer 21 which brings them into the bending area C.  A photo-electric cell senses the arrival of a glass sheet and commences a sequence which halts the forward movement of the sheet when between complementary shaping mould halves 105, 106 (Fig. 10), operates bending means whilst the sheet is stationary and then conveys the sheet away at an accelerated speed.  A piston cylinder 152 then operates to move a cam 148 downwardly.  Followers 147, attached to pivotal arms 113 on which the mould halves are mounted, then cause the mould halves to swing together under the action of a spring 130 thus pressing the glass sheet positioned there-between. The mould half 105 is of the concave open ring-type and mould half 106 solid convex. Both halves are covered with glass cloth.  The piston cylinder 152 then retracts, against the action of a checking piston 163, to open the mould halves.  The now bent sheet is conveyed to the tempering section at an accelerated speed until it passes another photo-electric cell whence the conveyer reverts to its original speed and the sheet is then transferred to a further conveyer 22.  The tempering section D comprises opposed chilling boxes 190 (Fig. 4, not shown) the faces of which are provided with a multiplicity of geometrically arranged tubes 204, four to six inches long, 0.314 to 0.365 inch internal diameter and set on 0.6 to 1 inch centres.  Cold air at up to 30 inch w.g. pressure is fed through the tubes to both temper the glass sheet and also to support the sheet from touching the faces of the boxes 190.  The tempered sheets then pass to a take-out section G.  Thin wires 186 (Fig. 10) in the bending section and 243 (Fig. 2) in the take-out section support the sheets S.