Patent GB-1413320-A (GB)
Title: Process and apparatus for manufacturing flat plastics-coated objects
IPC: B30B1/34
Filed: 1972-12-29
Abstract: 1413320 Laminating method and press POLYFONT 29 Dec 1972 60129/72 Heading B5N In a process for the production of a flat article having a finish on at least one of its surfaces, wherein a blank of the article is arranged between a pair of press plates with a layer of material for forming the finish disposed between the blank and at least one of the press plates, and pressure is applied to one of the press plates so as to compress the blank and the layer(s), the pressure being applied initially throughout a first zone extending linearly across a part of the press plate and subsequently throughout a zone extending linearly across a part of the press plate and located beside the first zone, the press plate being deformed during the initial application of pressure thereto. A press for carrying out the process includes a pair of press plates, one of which is flexible, and a device for applying pressure to said flexible plate, said device comprising first means for applying pressure to a first zone extending linearly across a part of the flexible plate, and second means for thereafter applying pressure to the flexible pressure plate on a zone extending across a part of the flexible press plate and located beside the first zone. The press described comprises a frame 11 having a base-plate 12 equipped with heating resistances 14 and carrying a mould 13 mounted thereon, the upper plate 16 being formed by interposing a corrugated sheet 18 between two planar sheets 17 and 19 and carrying a vertically depending lip 41, e.g. of rigid rubber, to seal the space 43 between the two press plates when the press is closed, heating resistances 20 for the upper plate being embedded in compressable insulation material 21. The upper plate 16 is supported from cross-pieces of the frame 11 by a row of hydraulic jacks 22, the axes of which intersect the longitudinal centre line of the plate 16, a further row of jacks 31 being provided on each side of the row of jacks 22. Orifices 45 drilled in the lower plate and connected to pump 44 are provided to enable a partial vacuum to be established in space 43. To permit complete descent of the plate 16, pad 42 is inflatable by a pump connected to the interior thereof by conduits. In operation of the press, all the jacks are operated to lower plate 16 to the desired level, the jacks 22 alone then operating to lower the longitudinal centre line of plate 16 and thus cause the plate to assume a convex form. The descent of the plate 16 continues and the members 34 engage the upper ends of their shackles 37, 38 so that the jacks 31 start to retain the edges of plate 16, pressure having been supplied to the pistons, to accentuate the convex form of the plate. Plate 16 then contacts the upper surface of the article 1 being processed in zone extending across its central part, vacuum in the space 43 extending the jacks 31 without reversal of the pressure fluid connections to the latter and thus decreases the curvature of plate 16. The pressure fluid connections to the jacks 31 are then reversed and the jacks cease to retain the edges of the plate, pressure being applied by the members 34 travelling down within their shackles. In a large press, an intermediate row of jacks 39 is provided between the row of jacks 22 and each row of jacks 31, the jacks 39 being operated prior to the reversal of the pressure fluid connections to jacks 31, the jacks 39 increasing the zone of contact between the plate 16 and the article. In the embodiment described, the inside surfaces of the mould 1 are provided with a coating consisting of a layer 6 of thermoplastic or thermosetting material, e.g. a thermoplastic polyester, and the layer flocked with glass fibres 7, the following components being stacked in the mould prior to the application of heat and pressure, a glass fibre fabric 8, a laminated wood panel 9, a further layer 10 of thermoplastic or thermosetting material and a glass fibre fabric 11.