Patent GB-826401-A (GB)
Title: Improvements in or relating to machines for manufacturing foundry moulds, cores or gates
IPC: B22C23/00
Filed: 1954-11-01
Abstract: 826,401. Moulding-machines. ABBEY, A. (Sutter Products Co.). Nov. 1, 1955 [Nov. 1, 1954], No. 31554/54. Class 83 (1). In a shell-moulding process, the mix is blown upwardly into a cavity defined by separable heated metal box-sections having sand-blocking air vents and a parting line disposed during filling in a first position in a non-horizontal plane until the cavity is filled, the air supply is shut off to permit the air pressure in the cavity to dissipate through said air vents, the surplus mix is removed after the initial setting of a layer of the desired thickness, and the box is then moved to a second position in which the parting line is substantially horizontal, the shell being maintained in the heated box for curing and the box-sections being then separated and the shell ejected. The apparatus comprises a pattern-box assembly B, a sand blow-chamber C, and a stationary sand hopper D. The assembly B is pivotally mounted so that it may be rotated by an air cylinder 14 through 90 degrees from the upright position shown in Fig. 1. An air cylinder 19 moves the blowchamber C on track 22 to the forward position shown for a blowing operation, and to a recharging position under the hopper D. The pattern-box-assembly B comprises corner-posts H and a transverse frame 35 through which the posts pass and which mounts the lower half 37 of a split pattern-box F locatted by a key 40 and held by clamps 39. A plate 44 through which the posts H pass, mounts a stripper-plate and gas burner assembly G through clamps 46, and normally rests on bell-crank arms 48 controlled by shafts 49 and actuating-arms 50. A gas manifold 52 communicates with the burners 53, which direct intensive heat on to the back of the lower box-section 37. An upper frame 57 is secured to the posts H and mounts the upper pattern-box section 58, and an upper plate 61 similar to the plate 44 mounts the upper burner and stripper plate 63, the plate 61 being spaced from the frame 35 by rods 68 passing through the frame 57 and engaging the frame 35 and rigidly attached to the plate 61. Spacers 70, slightly shorter than the normal spacing between frame 57 and plate 61, limit the upward movement of the frame 57 relative to the plate 61, which is normally urged downwards by springs 71. An actuating-plate 73 is secured to the posts H and to a piston-rod 74 actuated by a cylinder 75, so that all four posts may be simultaneously raised or lowered. Opening the pattern-box and stripping the shell is achieved by an upward stroke of the piston-rod 74, initial upward movement of the posts raising the frame 57 and upper box-section 58, while the plate 61 is held down by the springs 71, thereby stripping the shell from the upper box. After the clearance at the ends of the spacers 70 is taken up, continued movement of the frame 57 produces simultaneous upward movement of the plate 61 to increase the opening between the boxsections. When the posts H have completed about one-half of their travel, the plate 73 engages the plate 44, raising the stripper-pins to strip the shell from the lower-box-section, and continuing to raise the same until full boxopening is achieved. Reversal of air pressure in the cylinder 74 produces a reverse sequence to close the box-sections under air-pressure sufficient to withstand the blow pressures, whereafter the assembly B is rocked-over into fillposition by the air cylinder 14. Initial rocking movement moves a pivotally-mounted adaptorplate 29 downwardly to cover the opening of the blow-chamber 27, and on completion of the 90-degree movement of the assembly B, the blow-passage 30 registers with the sealing-plug 80 on the adaptor 28. Sand is blown into the box-cavity by introducing pressure air into the chamber 27 from a reservoir 85 fed by a flexible hose, a valve 28a being opened by exhausting air from the space 81 below an annular valveplug 82 and diaphragms 83, 84. When pressure air is restored to the space 81, the valve is closed and pressure air in the box cavity and chamber 27 gradually dissipates through the box vents, until valve 29a is opened further, exhausting air through the screened openings 88 while the box is lightly vibrated by a vibrator 30a, and allowing surplus mix to flow back under the influence of gravity without any sudden rush of air. If a small core is to be made, the blow-chamber is only partially filled, by using a baffle 90, the chamber C being placed under the hopper so that sand enters only through the passage 91. Preferably dual chambers 27a, 27b, with dual valve systems 93 are used. The burner-plate has a pattern of gas-passages, all communicating with the manifold 52, and any of which may be plugged so as to adjust the intensity of heat over the back of the box. An electrical control system automatically controls the machine cycle, including the maintenance of correct box temperature by the use of thermocouples. Safety switches responsive to expiration of pilot flames and decrease of flow of gas to the manifolds may be incorporated. Specification 794,903 is referred to.