GB637307A - Improvements in or relating to injection casting or moulding apparatus - Google Patents

Abstract

637,307. Injection - moulding machines. COULTHARD & CO., Ltd., W., and COULTHARD, W. April 11, 1947, No. 9643. [Class 87 (ii)] [Also in Group XXII] An injection moulding- or casting-machine has its nozzle rigid with a plunger arranged in the end of a cylinder so that when the cylinder and die are pressed together the plunger is forced into the cylinder and the metal or thermoplastic moulding powder &c. contained therein is forced through the nozzle into the die. Either the cylinder or the die or both may be moved and the line of movement may be inclined or horizontal or curved, e.g., a rocking movement. The cylinder 14, Fig. 1 is arranged in a melting pot 10 and has ports 16 which, in the normal position of the plunger 17, permit the material M to flow into the cylinder. The die halves 22, 23 are mounted on slides 20, 21 movable on rods 19, the half 22 being pressed up to its right-hand position by springs 25, Fig. 2, or fluid pressure through pipes 26 and the half 23 being moved by a piston in a cylinder 30 to close the die, press it till it engages the nozzle and then force the plunger 17 right into the cylinder 14 thus charging the mould. The nozzle is connected to the slide 20 by pins 28, Fig. 2, in slots 29 so that when the slide moves up to the right the die and nozzle separate to break the sprue and then the plunger is moved to its normal position to allow the cylinder 14 to refill. The plunger &c. may be arranged horizontally instead of inclined and, particularly if used for moulding powdered material, the inner end 38, Fig. 4, of the plunger may be flared and the material be introduced into the cylinder 33 through a funnel 35. The nozzle 39 may be forced outwardly by a spring 41 and be heated by gas, steam or electric means 44. In another modification the plunger 37, Fig. 5, has a large bore and a hole 36a to admit powder &c. and a fixed plunger 46 is arranged in the rear end of the cylinder. In this case a plunger-returning spring 41 may be arranged about the plunger 46. The movement may be effected by mechanical instead of fluidpressure means.