FORFARANDE OCH ANORDNING FOR BEREDNING AV SANDFORMAR

摘要

1465171 Foundry moulding E BUHLER 29 Jan 1974 [29 Jan 1973 12 Dec 1973] 04117/74 Heading B3G In a method of producing sand moulds using a mould frame or flask Ca, a pattern plate and a press punch Ba, the sand is introduced to the interior of the frame or flask through openings in the press punch whereby the sand flows in separate streams moving substantially perpendicularly to the plane of the pattern plate; the sand is fed from a chamber a by the impact of compressed gas supplied via a duct e1 and apertures 1, 3, and the sand is accelerated in the chamber by passing through a Venturi passage; further compaction of the sand in the frame is produced by relative movement between the pattern plate and press punch during which some of the sand returns to the chamber a through the press punch openings. Before the application of the relatively high pressure gas the chamber a may be subjected to a lower pressure gas for fluidizing the sand, such fluidization being continued during the pressing operation. In Fig. 1 there are upper and lower frames Ca and Cb each housing a pattern attached to a hollow pattern plate D which may be evacuated; the frames are associated with upper and lower punches movable into the mould frames. Each punch comprises an annular fixed cylinder Fa, Fig. 2, with an annular piston. In Fig. 1 the sand chamber is Venturi shaped, and in Fig. 2 Venturi passages are provided by an apertured duct 60 from which fluidizing gas is emitted. The lower frame Cb may move sideways and for this purpose two lower frames may be interconnected and swivelled about a vertical axis so that when one frame is in an operating position the other is free. Similarly the pattern plate may be in the form of a double pattern plate divided horizontally and rotatable about a vertical axis so that the upper halves can be changed with respect to the lower halves, Fig. 6, not shown. Instead of being rotatable the separate halves may be moved on rails. The flask-less moulds are fed in abutting relationship to a casting and cooling line moving at right angles to the moulding machine axis. Such transportation may be effected by apparatus including a supporting grid composed of a set of stationary bars interspersed with a set of horizontally and vertically reciprocable bars. During such motion the mould sides are engaged by pivoted clamping plates. In Fig. 10 the stationary bars 22a11l and the reciprocable bars 34b11l include U-shaped mould abutting members 22a11 and 34b11 urged upwardly by adjustable springs.