| 摘要 |
<p>1426306 Laminating press SEAL Inc 27 March 1974 [10 April 1973] 13584/74 Headings B5N and B5F A vacuum press comprises a platen assembly 4 comprising a frame, a flexible metal platen 132 supported only at its edges by the frame so that it can flex and also so that it can expand and contract in its own plane in accordance with changes in its temperature, and electrical heater means 140 for heating the platen, a work support assembly 2 comprising a frame and a flexible air-impermeable sheet 40 mounted at its edges to the frame, the platen assembly being connected to the work-support assembly so as to be movable into and out of engagement with the work support assembly and the platen assembly and work support assembly when engaged providing an air-tight work-receiving chamber therebetween with the platen and flexible sheet forming opposite side walls of the chamber, means, e.g. pump 52, for evacuating the chamber so that the atmospheric pressure exterior of the chamber will force the flexible sheet towards the platen and thereby compress a workpiece 230 supported on the sheet, and control means for operating the electrical heater means and evacuating means so that a workpiece in the chamber is heated and compressed. Flexible sheet 40 which may be made from synthetic rubber, e.g. silicone rubber, a plastics sheet or a rubber or plastics coated fabric, may be attached to gasket 51 of resilient heatresistant material, e.g. silicone rubber. Support means 70 located below the flexible sheet 40 for supporting the sheet at a selected height may comprise panel 86 made of asbestos supported by a second frame connected to the frame of the work support assembly by means comprising means for raising and lowering the second frame relative to the frame of the work support assembly. The platen assembly may comprise a rectangular frame covered by member 120 which comprises two thin aluminium plates 124 and 126 separated and secured to honeycomb reinforcing structure 128, flexible metal platen 132, e.g. of steel or aluminium, mounted on the underside of the frame and held in position by retainer strips 134, electrical heating means 140 comprising heating element 142 encased in heat resistant elastomeric material 144 and glass fibre heat insulating blanket 148. The platen is free at its edges to expand and contract in its own plane with changes in temperature and the heater means are preferably arranged so that heat input to the edge regions of the platen exceeds heat input to the centre region of the platen to compensate for radiative heat losses at the edges of the platen. Clamps 64 may be provided to ensure continuous sealing between the side margins of the platen and gasket 51. The press may be used to bond a graphic arts object, e.g. a photograph, to a transparent plastics covering film coated with adhesive and a backing sheet of cardboard, a dry mounting tissue coated on both sides with hot melt adhesive being provided between the graphic arts object and backing sheet.</p> |
