Patent GB-748551-A (GB)
Title: Improvements in or relating to foundry moulding machines
IPC: B22D17/32
Filed: 1952-12-08
Abstract: 748,551. Moulding-machines. BEECH, A. S.,and FOUNDRY EQUIPMENT, Ltd. Dec. 7, 1953 [Dec. 8, 1952; Feb. 9,1953], Nos. 31103/52 and 3599/53. Class 83 (1). A hydraulic squeeze - moulding machine comprises opposed platens and squeeze cylinder having an operating-member to urge the platens together, a pump having high and low pressure deliveries connected to the squeeze cylinder, and controlvalve means in said connections such that when the pressure exceeds a predetermined value, the low-pressure delivery is cut out and the highpressure delivery continues. A machine comprises a base 11, a ram 14 supporting a table 13, and an upper platen 36 carried on an arm 32 horizontally-swingable on a column 30. The table supports a platen 15 suspended therefrom by screws 20 in rubber bushes 18 bonded to frames 17, the arrangement being such that the platen is spaced from the table when no pressure is upon it, but when pressure is applied to the platen it is depressed into contact with the table. A switch 50 is actuated by movement of the platen to switch on a vibratormotor 21 as the ram moves up with a mould supported on the platen, and to switch off the motor as the squeeze pressure is applied. The motor is switched on again as the platen returns from the squeeze plate, thereby freeing the pattern from the sand, and switched off at the end of the return movement of the ram. A duplex hydraulic pump driven by a motor 41 comprises low-pressure and high-pressure sections 60, 61 respectively, the output being connected to the ram cylinder 12 by a pipe 42. The hydraulic system includes a controlvalve 67, relief-valve 64 of the highpressure section and an unloader-valve 69 in the low-pressure section, such that up to a predetermined pressure the two sections deliver in parallel to the valve 67, and above said pressure, and until the relief-valve 64 operates, the highpressure section only delivers to the valve 67. The valve is controlled by a pilot-valve 83 operated by a hand-lever 46 so that in one position of the lever pressure is applied to the cylinder 12 to raise the ram 14 and platen 15, and in the other position the pump output is delivered to the sump and the ram falls under gravity. In a modification, the machine comprises a ram supporting a lower platen working in a bottom box, a box-operating ram, an upper platen and, between the platens, a pattern plate carrying a pattern and a top box and pivoted so that it may be swung to one side. The hydraulic system comprises a duplex pump operating in a similar manner to that in the first embodiment. In operation, pilot-valve handles are operated to move the lower mouldbox and pattern upwardly to squeeze the sand against the pattern, they are then moved downwardly leaving the top box suspended so that the pattern and pattern-plate may be removed, and then the box and platen are moved up to close the parts of the mould together. The lower box is then moved downwardly while the lower platen is left raised, to strip the mould from the mould box. Specifications 416,116 and 434,833 are referred to in the second Provisional Specification.