GB1320855A - Pressure casting machine with pressure-increase system - Google Patents

Abstract

1320855 Hydraulic intensifiers WOTANWERKE GmbH 3 May 1971 [2 May 1970] 12822/71 Addition to 1268006 Heading F1D [Also in Division B3] In a hydraulic intensifier as claimed in parent Specification 1268006 for increasing the hydraulic pressure in the working cylinder space 43, Fig.1, on one side of a moulding piston 42 near the end of its stroke and comprising a stepped piston 52 which when fluid-pressure is supplied through a line 55 and a valve 100 to the larger face 53 thereof displaces a valve member against a seat 64 to cut off a low-pressure fluid supply through a line 47 to said space 43, the pressure therein then being intensified whilst the pressure in the annular chamber 58 of the intensifier cylinder 51 is maintained at atmospheric pressure, the valve 100 has a member 106, Fig.2, which is slidable in a chamber 104 to abut a seating 107 thereby isolating pressure line 55 from cylinder chamber 67, and member 106 has a shoulder 108 open to line 55 whilst chamber 104 is connected either to a further pressure source 49 or to a vent line 118 according to whether a slidable control member 113, 114 is subject to a predetermined high control pressure in a line 65 connected to the working cylinder space 43. The initial past of the working stroke of piston 42 is effected by moving a valve 45 to the right followed by moving a valve 50 to the left whereby pressure fluid passes through lines 47, 48 and apertures 63 in an extension 71 of piston 52. When pressure in 43 rises piston 52 moves to the left to seat at 64 and thus close apertures 63 thereby pressurizing the fluid in cylinder space 43.