GB1339934A - Hydraulic press - Google Patents

Abstract

1339934 Hydraulic press AMACKER & SCHMID AG 16 Sept 1971 [2 Dec 1970] 43126/71 Heading B5F An hydraulic press for use in glueing workpieces and stamping operations comprises a first pressing unit 5, 6, 9 for carrying out the approach stroke of a platen 3 under high speed and low power and a second pressing unit 12, 13, 14 for carrying out the pressing stroke under low speed and high power. The first unit comprises a cylinder 5 and a piston 6 formed by the upper end of a ram 4 and having a small effective surface area compared to that of a diaphragm 12 of the second unit. As shown, during a work cycle, pressure fluid is fed from a pump 23 into chamber 9 of the first unit via a valve 10 to force the ram 4 into contact with the workpiece against return springs 17. The valve 10 is then closed and pressure fluid is fed into chamber 14 of the cylinder 13 of the second unit so that the diaphragm 12 is forced down against a thrust plate 16 in contact with the cylinder 5. The plate 16 is provided with lugs 16a to limit the travel of the diaphragm 12. One or more bolts 19 may be provided on the cylinder 5 to pass through apertures in a ram plate 18 and a frame plate 20 to limit the stroke of the ram 4 relative to the cylinder 5 and to inhibit rotation of the cylinder 5. The piston 6 is provided with a sealing ring 7 sandwiched between slip rings 8. The frame 1 may comprise a steel slab. The press may be manually or automatically controlled. The latter may depend upon measurement of fluid pressure or volume or of time. A relief valve and pressure fluid accumulator may be provided. The hydraulic circuit shown is described.