GB860038A - Apparatus for bending glass - Google Patents

Abstract

860,038. Glass sheet bending. PITTSBURGH PLATE GLASS CO. March 19, 1958 [March 28, 1957], No. 8772/58. Addition to 845,963. Class 56. In a glass sheet bending mould as in the parent Specification the smoothly surfaced rigid sheet forming the glass supporting surface is spaced laterally outboard of the adjacent one of the centre rails so that the glass supporting surface is spaced traversely therefrom, whereby, after bending, a portion of the periphery of the glass sheet is spaced from the rail and a compression stress is developed in the edge during cooling. As shown in Figs. 3 and 4, the mould comprises a centre section 39 and end sections 43, 44 rotatable relative thereto about stub hinges 48 attached to the centre rails 40, 42 by metal straps 49 extending inwardly from the end rails 45, 46 and which terminate in lever arms 50, 51 on which counterweights 52 are secured, the centre section 39 being connected by angle braces 32 and rods 36, 38 to a frame 20. Fingers 54, 58 adjacent the extremities 56 of centre rail 40, and spaced outwardly therefrom, align the glass sheet G during bending and they may be covered with a facing 59 of asbestos glass fibre cloth or the like. The slide bar 70 is spaced outwardly of centre rail 42 and slide bars 72, 74 outwardly of and rails 45, 46 from the ends of bar 70 to just past the extremities 76, 78 of the mould. The bars 70, 72, 74 extend obliquely upwardly and outwardly of the rails to provide a rigid support for the edge of the flat glass sheet G and are secured to the rails as in Fig. 4 with a spacer sleeve 77 surrounding a bolt 75. The edge of the sheet slides down the surface 71 of the bars to lie on the rails with the overlap to give the compression stress. A heat abstractor member 64, provided for maintaining a relatively flat area adjacent rail 40, comprises one or more metal plates 66 with an overlying larger metal screen 68. Abstractor members 80, 82 (not shown) are provided on rails 45, 46 as well as end members 84. As shown in Fig. 7, a similar mould structure is designed to produce a windscreen with sharply curved centre section extending into the roof, and the centre rail 142 and end rails 145, 146 have slide bars 170, 172 and 174. The rail 142 is reversely curved at each end and the bar 170 corresponds thereto so as to form the roof section on bending. Specifications 811,279 and 845,962 also are referred to. Reference has been directed by the Comptroller to Specification 820,809.