GB1369775A - Presses - Google Patents

Abstract

1369775 Compression moulding AE & CI Ltd 1.5 March 1973 [29 March 1972] 12584/73 Heading B5A In a press platen for compression moulding a plurality of articles, e.g. explosives and pharmaceuticals from powders, comprising plungers 46 which extend from the platen into dies (not shown) are engaged by pistons 38 sliding in bores 32 which are connected to a source 34 of fluid under pressure and have drain connections 36, fluid passing to the drain is prevented from reaching each plunger by an impervious tube 37 surrounding the plunger in the region of the chain connection and by a tubular skirt 40 on the piston surrounding the tube 37. The skirt is perforated at 42 for fluid between it and the tube 37 to escape to the drain 72. Relatively narrow portions 50 of the plungers 46 pass through a retaining plate 56 attached to the platen and through a stripper plate 60 slidably connected hollow bolts 63 attached to the platen and biased away from the platen by springs 64. The narrow portion 50a (Fig. 2, not shown) of the plunger 46 may be a separate member having an enlarged head (76) for retention by the plate (56a). In use an assembly (Fig. 6, not shown) of a base-plate (88), an apertured plate (80) accommodation sleeves filled with powder to be compacted, and a cover plate (84) having bores for plunger portions 50 to pass through, is placed on the lower platen of a press and the lower platen is raised. The cover plate (84) engages and raises the stripper plate 60 and the plungers engage the powder and are forced upwards, displacing fluid from chamber 34 into the chamber of a control piston (not shown). When the control piston. reaches the end of its travel, full pressure is applied to the powder to compact it.