GB1160754A - Improvements in or relating to Injection Moulding Machines - Google Patents

Abstract

1,160,754. Injection moulding. SOC. POUR LA TRANSFORMATION DES MATIERES PLASTIQUES STAMP. 8 Aug., 1966 [13 Aug., 1965; 14 Feb., 1966], No. 35366/66. Heading B5A. An injection moulding machine comprises a stationary mould part 2 which forms at least part of the configuration of the mould, guiding columns 6 attached directly to the stationary mould part, a movable part 10 slidably mounted on the guiding columns, a mould closing mechanism 11 supported by the guiding columns 6, a mould latching jack 7, a latching chock 8 movable perpendicularly to the direction of movement of the movable mould part into a position between the latching jack and the movable mould part so that a latching force can be transmitted to the movable mould part from the jack through the chock. The machine may be used for making bottle crates of polyethy - lene. A screw 12 feeds the plastics material into a reservoir 13, an exit thereof to the mould being controlled by a valve 14. The plate 5 is locked in position during moulding (Fig. 1) by a vertically reciprocable chock 8 which is acted on by a short stroke piston 9 to effect locking. In a modification (Figs. 3, 4, not shown) a frame (49) supports four radially reciprocable mould side parts (22) independently of the plate 5, the frame (49) being reciprocably connected by jacks (26), (27) (28) to a female mould plate (20) such that on opening after removal of the chock 8 the crate is withdrawn with the part 3 while the jacks move the frame (49) from making engagement with the plate (20), parts 22 being simultaneously withdrawn transversely to the direction of movement of the part 3 by jacks (23), (24), (25). In this embodiment the reservoir 63 is connected by valves (37), (38), (43) to a transfer pot (29) holding sufficient material to fill the mould in one injection. Plastics material in the reservoir is compressed due to the action of a hydraulic chock (40) which restricts retraction of a cylinder (39) connecting the continuously rotating auger 12 with the reservoir. Injection may be effected without using the transfer pot. Also in this embodiment sprue channels (51) into the mould (Fig. 5, not shown) are heated electrically so that only a very small "plug" or "stub" of material is left in the formed article, the plate (20) comprising two spaced parts (20) and (53). In a further embodiment (Fig. 6, not shown) the auger (61) and reservoir (62) are disposed mutually perpendicularly, the latter being perpendicular to the transfer pot (64). At the end of injection, a valve (67) to the mould is closed, and a valve (66) opened, a jack (68) is activated to force the head (63) thereof downwardly to cause residual material in reservoir (62) to flow therefrom to the pot (64), which is continued to be filled by the continuously rotating auger. When the pot (64) is filled with the correct amount of material for injection, valve (66) is opened and material is discharged into the reservoir once more, the ram therein retracting. Injection takes place when valve (67) is opened and a transfer ram (65) operated. The speed of the auger is regulated by a belt and cone gear system.