| 摘要 |
779,333. Shaping glass. PITTSBURGH PLATE GLASS CO. Feb. 10, 1956 [March 23, 1955], No. 4284/56. Class 56 In a convex glass bending mould, supporting means are provided for exerting a force against the glass to support it between points at which pressure is applied thereto during a heating process, the supporting means being such as to cease to exert such force upon positive movement of the glass a predetermined distance against the force. In a mould 2, which is provided with a pressure device 4 as described and claimed in Specification 763,698, the supporting means comprises a pair of U-shaped arms 5.lying between the centre part of the mould, where the glass sheet 3 is supported substantially flat, and the end where pressure is applied by the device 4, each arm 5 being pivoted to the inside of the mould by a pin 6 at one end, the other free end 7 bearing against the glass sheet 3. On the outside of the mould, each pin 6 is used to secure a bracket 6a holding a tube 8 in which a ball 9 is free to roll. As shown, prior to bending, the balls 9 lie on the side of brackets 6a remote from the supporting ends 7 which are pressed upwardly against the glass sheet 3, upward movement being limited by stops 19. As the glass sheet is pressed downwards, the arms 5 pivot about the pins 6 and the balls 9 roll to the other end of tubes 8, where they are held by bars 8a, the weight of the balls holding the free ends 7 so that no upward force is exerted on the glass sheet 3. Other forms of over-centre mechanism, to replace the tube 8 and balls 9, are suggested. |
