GB960209A - Moving bolster presses - Google Patents

Abstract

960,209. Metal working presses. WILKINS & MITCHELL Ltd. May 15, 1963 [June 19, 1962; July 25, 1962], No. 19396/63. Heading B3H. A moving bolster press comprises an air cushioned bed 11 located between four posts 10, a pair of tracks 15 extending from the opposite sides thereof in alignment with tracks 16 on the bed, which comprise a centre portion 17, and a pair of bolsters 20 each having transversely mounted driving wheels 22 for engagement with said tracks. The under face of each bolster is formed with eight wedge engaging surfaces 24, symmetrically arranged two on each side of the longitudinal axis thereof and the bed 11 has horizontal wedge engaging surfaces 29. The bolster is moved into engagement with fixed stops 49, locked in position by a pair of hydraulically operated vertical keys 43, retained transversely by shelves 42 and raised into engagement with stop members 41 by a pair of " E " shaped hydraulically operated wedge members 30, arranged one along each side of the bed 11, the legs of each member having an end wedge portion 33 which engages the wedge surfaces 29, 24. The wedges are operated by a pair of hydraulic cylinder units placed on each side 37 of the bed. These units and the vertical key members are controlled by a pump 45 which comprises a plurality of identical pistons 46 secured to a piston-rod 47, each piston 46 co-operates with identical pumping cylinders arranged in tandem and the rod 47 is actuated by a pneumatic piston 50 attached thereto via a solenoid valve. The hydraulic circuit comprises solenoid oil valves 54, check valves 56 and a common line 57, Fig. 6 (not shown). In the locked condition all the solenoids are de-energized, the pump and key cylinders linked to the common line which is maintained at 2000 P.S.I. and pressure switches 62 closed. To release, the control switch is moved to " out " which stops the pump and energizes the solenoids, when sensing switches (not shown) indicate that the valves have " changed over " the pump restarts and the wedges retract at a common speed. Should any pressure switch operate before all wedges are within the last <SP>1</SP>/ 1 6 th inch of the stroke, that is before limit switches are operated by the wedges, the pump will be stopped and a warning signal given. Sensing switches indicate when the keys and wedges are out and that the bolster can be moved. When the wedges are within the last <SP>1</SP>/ 16 th of an inch of travel and any one of the pressure switches 62 operate, the interconnecting solenoid 58 is de-energized so that all lines are connected to the common line and the wedges and keys positively held out against their stops. Locking is carried out by reversing the above procedure. Alternatively, the pistons may be arranged in parallel and be independently driven, e.g. by an hydraulic pump.