Patent GB-1443579-A (GB)
Title: Metal-casting moulds
IPC: B22C9/20
Filed: 1973-12-21
Abstract: 1443579 Flasks; moulds; moulding-machines; patterns E BUHRER 21 Dec 1973 [27 Dec 1972 9 Oct 1973] 59483/73 Headings B3F and B3G A mould-part 85, Fig. 4 (for stacking with others to form mould cavities between adjacent parts) is produced by injecting moulding material (a plastics/sand mix) into the cavity enclosed between two pattern plates 1, 2 by a flask 16 sandwiched between them, the cavity being filled through an opening in the flask; when the part 85 has hardened it is removed. The mould-part 85 may be removed in the flask 16, after separating the pattern plates 1, 2 by cylinders 14, before removal from the flask before stacking. For larger patterns, the pattern plates and flask are clamped together by fasteners in a vertical position, for filling, before turning to the horizontal for loosening of the fasteners and lifting off of one of the plates so that the remaining assembly can be inverted to be lowered on to a mould stack, Fig. 16 (not shown), to release the mould-part. Guide bushes (150) are embedded in the part, for alignment by dowels. Each mould-part has an inlet for the molten metal, that of the bottom part of a vertical or inclined stack of the parts being closed by a plug (107), Fig. 11 (not shown), and at least one pouring basin (117) attached to the top mouldpart if there is to be top-pouring. A stack is held between end plates by two clamping frames, for bottom pouring through a downgate inside the stack or one outside the stack or stacks, or a stack is surrounded by an assembled shell (156), Fig. 17 (not shown), with an intervening layer of binderless sand, on a bottom plate for top-pouring castings produced from larger patterns. The preheated pattern plates 1, 2, possibly each in two parts 5, 6, Fig. 1, separated by a bar 7 or 8, are held by magnets 9, or suction if non-magnetic, on base plates 10, 11 each together with two edge bars 40, Fig. 4 (44) and 41, 45, Fig. 1, mutually at right angles. The pattern plate parts and bars are urged by a system of levers, Figs. 13, 14 (not shown), on the base plates, against or towards angled stop-faces 55, 56 at the remaining edges. Electric heaters 12 are provided in heat insulation backing (13). A number of moulding units, e.g. four, may be mounted, Figs. 5, 6 (not shown), with the plates vertical, on a turn-table (34) in radial planes around a vertical axis about which they can be rotatably indexed from, and eventually back to a position where charging of the moulding cavity, by a blow head (38), Fig. 8 (not shown), through bores (36) in the flask 16, and ejection of the moulded part take place. A piston head engages a slot 26 in the flask 16 to pull it out from between the pattern plates 1, 2. A plate (75), Figs. 7, 10 (not shown), is then advanced to hold the mould-part 85 by suction and pass it into a U-fiame (83) by which it can be swung down to the horizontal and released on a stack of mould-parts. The pattern plates 1, 2 may be in several parts. The flask 16 may be in two parts to be separated, after plate removal, to release the mould-part. It has bores (72) to reduce heat losses in operation. There may be patterns on both sides of the pattern plates and if the four units are used there may be eight different pattern systems. Four mould-parts are then produced and stored and then the plates are changed over to produce sequentially the mouldparts to be interleaved in a stack with those from stack, when cores have been fitted. In another embodiment, upper and lower guides for the flask (201), Figs. 18-23 (not shown), are vertically movable and similarly movable clamping jaws (206, 207) by means of a wedging action, hold the sandwiching pattern plates (240, 250) about the flask. Instead of the jaws at each upper and lower edge, a clamping frame may be used. The pattern plates are again moved by cylinder or motor-driven screw with the stroke of one limited at the side of the moulding unit where a tongue (267) extends along the edge of the flash (201) to locate on a liftable support (202) for the flask. Flasks of different thicknesses but having tongues of the same thickness can be used in the same supports. If used with a turn-table, flasks of different thickness may be used at the same time. This embodiment may be operated both with a manual follow-up control and with a centralized control.