GB1109391A - Board-forming method and machine - Google Patents

Abstract

1,109,391. Moulding plaster board. UNITED STATES GYPSUM CO. 20 April, 1965 [29 April, 1964], No. 16589/65. Heading B5A. In a machine for continuously forming folded edge gypsum plaster board, a lower paper cover 46 is scored with parallel fold lines (50 and 52), (Figs. 2-3, not shown) at each edge, providing board edge portions (54) and strips (56) for underlapping a top cover-sheet (60), and is delivered over a support bed 26, which may be a stationary surface or comprise rollers, which is provided, along the sides of a first inclined portion 62 thereof, with ramp surfaces (94a) (Figs. 12-15, not shown) which converge towards the centre axis of the web and up which the edges of the web rise and, in a second horizontal portion 64 where gypsum is deposited from a pipe 58 into a narrowed and deepened trough-shaped bottom cover (46), is provided with parallel ramp surfaces (96a) and vertical extensions (98) thereof (Figs. 16 and 17, not shown) which converge towards the axis of the web and are followed by parallel ramp surfaces (74) and vertical extensions (68) (Fig. 18, not shown), which may be provided with clips (90) to engage over the edges of the web (46); a third section 66 of the support bed 26 slopes upwardly to the nip between bed 30 and forming roller 32 and is provided with ramp surfaces (80) (Figs. 9-11, not shown), and vertical extensions (76a and 76b), which may also be provided with guide fingers (92) to ensure that edges (56) fold inwardly, which diverge outwardly from the axis of the web to terminate adjacent the nip at parallel vertical edge formers (78) of the width of the finished board. The top cover-sheet (60) is applied to the edges (56) above bed section 66 over adjustable arcuate guide 100 and adjustable plate 104 (Figs. 5-7, not shown) which extends to the roller nip and is provided with ramp surfaces 106a, 106c at its edges to bring the edge portion of the top and bottom sheets into early contact. An applicator 112 coats the contacting edges of the cover (60) with adhesive. The bed section 62 may slope downwardly to section 64 or may be coplanar therewith; stationary plates may be substituted for rollers 32 and edge formers may be employed to produce tongue- and-grooved board. The ramp surfaces (74) are mounted, via an extension (68), on support brackets (70, 71) (Fig. 4, not shown) adjustably supported on the machine bed frame and the ramp surfaces (80) are adjustably pivoted to extensions (68) via extensions (76a, 76b). The delivery of the slurry into the narrowed and deepened trough formed by the bottom sheet (46) and the application of the top sheet (60) thereto contains the slurry within the sheets (46 and 60) and out of contact with the machine parts.