GB829466A - Method and apparatus for bending and cutting glass sheets - Google Patents

Abstract

829,466. Shaping and cutting glass sheets. LIBBEY-OWENS-FORD GLASS CO. Sept. 17, 1957 [Sept. 19, 1956], No. 29191/57. Class 56. To produce a pattern cut bent glass sheet, a blank size glass sheet is heated and bent into conformity with the shaping surface of a mould, marked while still in contact with the shaping surface to reference the sheet with respect thereto and the predetermined path of travel of a glass scoring tool then orientated with respect to the marked portion to position the path of travel with respect to the shaped surface and the glass scoring tool moved in contact with the glass sheet to score the sheet to pattern outline. The glass sheet is differentially cooled to form compression stress in a sheet portion corresponding to the marginal edge area of the required pattern, the scoring tool passing through the stress area. The bending mould 17 comprises a central section 18 and rectangular end sections 19 pivoted together on hinges 21 and forming the shaping surface 20. The mould 17 is supported on a base 22 by transverse rods 23 on end sections 19 secured to links 24 swinging on pins 25 fixed on posts 26. A heat absorbing member to retard the cooling of the central areas c of the glass sheet comprises a metal shield 30 on a rail 29 supported on posts 31 carried by rods 32 fixed to the sections 18, 19, the shield 30 being in sections to move therewith. The marginal areas a of the sheet will also be retarded in cooling by the shaping surface 20, leaving an area b under compression stress. For marking the glass sheets 27, each end section 19 carries a tubular member 33 supported by a post 34 on the rod 23 and passing through the shield 30 to lie substantially normal to the sheets 27 after bending. The two sheets 27 laid on the opened mould 17 are passed through the bending furnace and the furnace annealing section and are then, at the unloading position, marked by operators at each side using a handled tool passing through the guide tube 33 and having a pad of rubber with a cross inked to give a mark f. The two sheets 27 are then secured together by spots of adhesive e and removed to the cutting machine, Fig. 6, which comprises a template 42 in the form of a rail on which the scoring tool 44 runs, supports 43 for the glass 27 and aligning bars 49 each having a pointer 50 to be aligned with a mark f. The tool 44 is supported on rollers 46 so that the wheel 48 is always positioned normal to the glass and the wheel 48 is moved towards and away from the glass by air-actuated mechanism in a cylinder 47. The cutting line d is arranged so as to be centrally of the compression stress area b. After the top sheet is scored, it is removed and the lower sheet then scored. Specifications 764,448, 764,566 and 773,417 are referred to.