Patent GB-1371388-A (GB)
Title: Injection moulding amchines
Inventor: ULMSCHNEIDER L A
IPC: B29C45/53
Filed: 1971-11-04
Abstract: 1371388 Injection moulding EASTMAN KODAK CO 4 Nov 1971 [4 Nov 1970] 51377/71 Heading B5A An injection moulding machine comprises a plurality of mould assemblies 60 which are continuously driven past at least one extruder 12. The assemblies are mounted on an annular rotor 11 which is continuously driven by a motor 36 via a variable speed transmission 37 and gear and pinion 56, 40. Each mould assembly 60 comprises upper and lower dies 148, 114, one or both of which may be movable. As shown, the upper die 148 may be raised and lowered by an hydraulic cylinder 142 between guide rollers 156 mounted on eccentrically movable arms (158, Fig. 4). The lower die 114 is provided with one or more injection chambers 118 which are filled with fluid moulding material as the lower die 114 slides over the upwardly urged plenum 170 of the extruder 12. The plenum (Figs. 8, 9) may be provided with a curved slot opening 180 fed by a plurality of conduits (182, 184, Figs. 8, 9) which may be heated (186, Fig. 9). After filling, a ram 128 is forced upwardly through the chamber 128 by a cylinder 124 to inject the material into the mould cavity or cavities which at this stage may still be open or may be closed by the upper die 148. After the material has cooled and/or cured the ram 128 is retracted bringing with it any surplus material left in the chamber 118 and sprue 120. The upper die 148 is then raised and ejector pins 150 passing therethrough deposit the article(s) on to an endless belt or rotary take-off conveyer 13 passing between the open dies. The conveyer 13 may take the articles to a vertically moving conveyer. Surplus material may be removed from the chamber 118 either by a pin 132 passing through the ram 128 and relatively movable with respect thereto or by undercuts (129, Fig. 5b) in the ram 128 which drag the set slug of surplus material (133, Fig. 5b) downwardly so that it can be swept across the surface of a ram guide 130 by a scraper blade into a collector for storage or return to the extruder 12. The upper die piston 142 is actuated by fluid fed through a line 44, a stand pipe (28, Fig. 2) a rotatable plenum 30 and lines 72, 62 from a pump 41 and may be controlled by a valve 162 via a cam ring 48, rod 168 and lever 166. The lower die piston 124 is actuated by fluid fed through a line 45, a stand pipe (32, Fig. 2), a rotatable plenum 3, and line 74, 64 and may be controlled by a valve (160, Fig. 2) via a lever (164, Fig. 2) and a cam ring 47. The cylinders may act under the same or different pressures. The cam rings 47, 48 may be replaced by pneumatic, hydraulic or electrical devices. The rotor 11 may be braked by pads (50, Fig. 2) actuated by hydraulic cylinders (49) and may be provided with water cooling manifolds 68, 70. The extruder 12 may comprise a continuously rotating or reciprocating screw or a pulsating pressure device. The extruder 12 may be vertically adjustable (Fig. 3). A moulding cycle may last 360 or 180 degrees. In the latter case two extruders are provided. The plenum 170 may feed material downwardly into the upper die or through a radial opening in the peripheral surface of a die. The conveyer 13 may be located adjacent to or above the extruder 12, may be vertically adjustable, and may be provided with a detector or be spring- loaded so that if a mould fails to open, the conveyer can be automatically swung away from the machine. The dies may be heated or cooled and may be provided with Y-shaped sprues. The ejector pins 150 may hold the article(s) after ejection so that it can be stripped therefrom at a desired location by a fixed arm. The mould assemblies 60 may be integral with the rotor 11 or adjustably attached thereto by members 110. Materials that can be moulded include allyls, cellulose esters, epoxies, fluoro-hydrocarbons and vinylidenes, melamine-formaldehydes, nylons, phenolformaldehydes, phenoxies, aliphatic and aromatic carbonates and esters, olefins, sulphones, styrenes, butadienes, urethanes, chloride hydrocarbons, vinyls and vinylidenes.