Patent GB-831313-A (GB)
Title: Glass bending mould
IPC: C03B23/027
Filed: 1957-10-23
Abstract: 831,313. Bending glass sheets. PITTSBURGH PLATE GLASS CO. Oct. 23, 1957 [Jan. 8, 1957], No. 33136/57. Class 56. A concave glass bending mould has a heater assembly secured to the mould in position for subjecting glass on the mould to localised heating, the assembly comprising a frame structure, at least one heater element supported thereon and reflecting means mounted on the side of the heater element remote from the glass for reflecting radiant heat from the heater element towards the glass. The mould comprises a central stationary mould with elongated side bars 1, 1<SP>1</SP> and movable end mould portions 2 each with a bar 3 forming a continuation of the side bars 1, 1<SP>1</SP> in the closed position. Each end of each bar 3 is connected by struts 4 to a semi-circular plate 5 pivoted on a plate 7 each pair connected by bars 82, the bars 82 connected by a bar 64. Arms 6 connected to each plate 5 and struts 4 carry a series of weights 8 for moving the end portions 2 about the pivots 7 to close the mould as the glass 9 softens, the movement being limited by adjustable stops 10 on shelves 11 secured by brackets 12 to the lower part of side bars 1, 1<SP>1</SP>, the end of each arm 6 moving into a forked guide-member 13 on the shelf 11. The brackets 12 also serve to secure the mould to a framework 14. A teeter device 15 as disclosed in Specification 804,577 and a thermal ballast device 25, 26 as disclosed in Specification 822,938 are incorporated and, as in Specification 806,498, a heater 24 is supported on supports 23 at each end of the mould to be under the glass at the line of maximum transverse bending. The upper heater assembly 30 consists of a flat sheet 31 of perforated or expanded metal mounted in a frame 32 of mild steel bars to be over a number of heater elements 34, 35, 36 with coils extending longitudinally of the mould supported on transverse bars 33 and a heater element 37 with coils extending transversely of the mould supported on longitudinal bars 29 connected to bars 33. The elements are connected in two circuits, the first from a contact 38 and connecting strap 47 through one end heater 24, the element 35, the other end heater 24 and strap 47 to a contact 39 and the second from a contact 40 through strap 47 to elements 34, 37, 36 and strap 47 to a contact 41, the contacts 38, 39 when passing through the lehr, engaging a pair of bus-bars extending along the upper central part of the lehr followed by engagement of the contacts 40, 41. Conventional wall and ceiling heaters are also provided in the lehr. Each of the contacts 38-41 is pivotally secured between bars 42 by a pin 43 on the end of a bent support member 44 projecting upwardly from an insulated mounting 45 on the framework 14, the other end of bars 42 being connected by a pin 46 which bears against the member 44 to limit rotation of the contact assembly, the weight being arranged to hold the contacts firmly under pressure against the bus-bars. The heater assembly 30 is strengthened by struts 50 and secured to a bar 48 pivotally mounted by arms 49 on pins 51 carried by insulated mountings 52 on the framework 14. Arms 53 project rearwardly from the bar 48 and converge to a lug 54 from which depends a bar 55 having a recess 551 to engage over a projection 56 at the foot of a framework 57 to hold the assembly in the raised position while the glass 9 is placed in position, the framework 57 carrying an adjustable stop 84 to limit downward movement to the full-line position of Fig. 5. The glass 9 is cut with pointed end portions to be bent transversely to form the wrap-around sides of a windscreen and an apron to be bent longitudinally to form part of the roof, the apron being supported on a shelf 63 extending behind the side bar 1<SP>1</SP>, the ends on the tips 16 of the end portions 2 and the main body of the glass on the lugs 22 of the teeter devices 15. The degree of bending of the gless is detected by a pointer mechanism 65 comprising a feeler 66, to engage the central part of the under surface of the glass, pivoted about a pin 69 on lugs 70 on a base 71 secured to the framework 14, the other end 67 of the feeler 66 moving over a scale 68 to the desired ultimate position 72. The scale 68 is formed at one end of an arm 73 pivoted on pin 69 and adjustable by a screw 74.