GB1213344A - Improved powder-compacting press - Google Patents

Abstract

1,213,344. Powder compacting press. ALLMANNA SVENSKA ELEKTRISKA A.B. 25 April, 1968 [28 April, 1967], No. 19586/68. Heading B5A. A powder-compacting press comprises a pressure cylinder having an inner wall lined with elastomeric material and a pressure chamber surrounding the elastomeric material, two punches insertable into the cylinder and inside the elastomeric lining from opposite ends of the cylinder and means for supplying a pressure medium to the pressure chamber. Each punch is preferably fitted with a sealing ring of elastomeric material. As shown, the two punches 8, 9 are integrally formed with pistons 6, 7 moving in cylinders 4, 5. The piston and cylinder are made double acting by caps 10, 11 and the ends of the punches are fitted with sealing rings 16. The pressure cylinder 30 contains an elastomeric sleeve 17 integrally formed with rings 18, 19 at each end which are secured against a shoulder 23 in the cylinder 30 by a sleeve 20 and intermediate rings 21 and 22 at the upper end and by springs 27, intermediate rings 25, 26 and sleeve 24 at the lower end. Pressure fluid is supplied to the space between the sleeve 17 and the pressure cylinder 30 from a channel 31 and the whole cylinder can be swung out of the line of the punches by means not shown. At the start of an operating cycle, both pistons are fully retracted. The pressure cylinder 30 is swung into position and the bottom punch 8 raised into the cylinder. Powder is poured into the moulding cavity, the top punch 9 is lowered on to the powder and both punches are actuated to compress the powder. Pressure fluid is then supplied to the outside of the elastomeric sleeve via channel 31 and the powder is compressed; the cylinders 4 and 5 operating the punches being hydraulically connected during this step to equalize pressures and movements of the punches. The pressure on the pressure fluid is then reduced and the punches are withdrawn from the pressure cylinder which is swung to one side, permitting removal of the moulded article. Further embodiments in which a groove is formed in the punches into which the ring 16 can partially retract under the moulding pressure and in which the pressure fluid supply to the elastomeric lining is through an annular member mounted in the cylinder 30 are also described.