GB1229631A - - Google Patents

Abstract

1,229,631. Foundry moulding-machines. SHERWIN-WILLIAMS CO. 28 March, 1968 [29 March, 1967], No. 14972/68. Heading B3F. [Also in Division B8] In a foundry moulding-machine, sand from a hopper 39 passes to a mixer 7 having three stages, one above the other and each including a rotatable arm (70 or 71), the sand flowing downwardly through the stages and being mixed with (resin) binder before passing to a blow reservoir 12 for blowing by a head 6 into an (aluminium) mould- or core-box. In the machine shown, the reservoir 12 is moved horizontally on rollers (11) by a cylinder 18 to a position beneath the blow head 6 where the box is clamped against the bottom of the reservoir by cylinders 24. The electrical circuit for controlling the machine includes a switch (137) for selecting automatic or manual control or a test circuit. The sand hopper 39 has a discharge spout 83 adjustable for outlet size by a hand wheel 85 and which is controlled by a pivoted gate 86 operated by a piston 87. The sand drops into a movable funnel 89 connected to a limit switch 90 and mounted in an outer funnel 88 for controlling the flow rate according to the weight. Each stage of the mixer has two curved arms (70, 71) and two scraper blades (75) rotated by a unit 41 including a motor (42). Each stage has a cylindrical shell 52, 53 or 54 one half of which is pivotable for access to the inside. A catalyst is fed into the first stage and resin binder into the second stage through motorized valves (120, 121) and nozzles (93, 96). When automatic running of the machine is selected and the level of sand-mix in the reservoir 12 is below a level indicator 130 and the reservoir is below the mixer 7 as shown, the indicator 130 and a limit switch (131), Fig. 6 (not shown), form part of a circuit and permit energization of a timer (161) for both the mixer motor (42) and a solenoid controlling the sandgate piston 87. The machine may be of a type in which the blow reservoir does not shift and has a valve at its fill opening; in that case the mixer control is interlocked with a level indicator and the valve. For manual operation of the mixer independently of the machine the controls 130 and 131 are by-passed. With the energization of the timer (161), the catalyst and resin valves 120 and 121 are turned on by a relay (160). To ensure proper flow of sand into the mixer 7, a flow timer (159) is also energized and when it times out it operates switches so that unless sufficient sand has fallen from the hopper 39 to trip the switch 90, the timers and relay are de-energized. The mixer motor (42), the sandgate solenoid and the catalyst and resin valves each have a switch (140, 141, 142 and 143 respectively) which has a run and a test position, the switches being in series in the run position.