GB963251A - Improvements in and relating to injection-moulding machines - Google Patents

Abstract

963,251. Injection-moulding machines. S. SZEKELY. Sept. 22, 1960 [Sept. 22, 1959], No. 32256/59. Heading B5A. In a horizontal injection moulding machine, material is injected into a mould clamped between two platens 8, 9 through a cylinder 4 in which slides a piston 6 manually operable by means of a hand wheel through a rack 19 and a pinion engaged by three speed gearing. A portion of the piston 6 which is tapered frictionally binds in a complementary portion of the cylinder end 30 so that on rotation of the hand wheel the cylinder 4 and nozzle 35 are carried forward with the plunger and no material is fed until forward movement of the cylinder is halted by closing of the mould halves between the platens 8, 9. A feed tube 11 which is rigid with the cylinder is also halted and a feed bar 16 slides in a feed tube 10 to push material into the cylinder 4 until an adjustable limit switch 15 closes a flap 12. An ejection pin 31 is provided, the piston is operated by an hydraulic or pneumatic cylinder 32 and a toggle plate 33 is rotatably mounted on a fixed plate 34 parallel with the platen 1 and is connected to the platen by two toggle bars 36 pivotally connected to the plate 33 and the platen 1. The mould platens 1 and 2 are both slidable on rods 3 in this embodiment and the cylinder 5 and the plate 4 are fixed. A lever 35 rotates the plate 33 and tends to straighten out the bars 36 which are normally in the oblique position shown. When the mould is closed further rotation of the plate 33 moves both platens to bring the mould into engagement with the injection nozzle.