GB557595A - Improvements in moulding presses - Google Patents

Abstract

557,595. Injection-moulding machines. BLUEMEL BROS., Ltd., and BLUEMEL, F. W. June 26, 1942, No. 8768. [Class 87 (ii)] A machine of the kind having a container 24 for the material to be moulded, a heater 23 for the material, a feed nozzle 22 and a mould 30, 35, all mounted for reciprocation by a power-operated bolster 15 towards a fixed plunger 25, is characterized in that the power for moving the bolster is controlled by an operating lever 43 which is automatically moved back and forth by means on the reciprocating parts of the machine. The bolster is raised by hydraulic rams 131 which are controlled by valves 37 which are opened in turn by a cam 39 secured to the lever 43 and oscillating therewith. The lever 43, pivoted at 42, is pulled counterclockwise by a spring 50 and clockwise by a weighted lever 55 pivoted at 54 on the lever 43 and having a hooked end 57 engaging a pin 58 on the lever 43, the arrangement being such that the lever 43 will stay in either of its extreme positions unless it is rocked a little way towards its other extreme position. Operation : In the position shown in Fig. 5, the bolster, mould, nozzle and container have been raised to their acme and an exhaust valve 37 is open (the other valve 37 being closed) ; accordingly, the bolster, mould &c. begin to descend, and a roller 64 on the bolster rocks counter-clockwise, Fig. 1, a lever 60 pivoted at a fixed point 61. The end 66 of the lever 60 engages the lever 43 and starts a swing-over movement which is completed by the weighted lever 55. At the end of the swing-over movement, the bolster, mould &c. are at their nadir, Fig. 1, the pressure valve 37 being opened and the exhaust valve 37 being closed. Accordingly, the bolster &c. begin to rise. When they have risen a little way, an abutment 59 engages the lever 55 and takes the weight off the lever 43 (the hook 57 receding from the pin 58). Later, an abutment 53 on the mould slide 17 engages the lever 43 and begins a swing-over movement which is completed by the spring 50, the position then being as shown in Fig. 5. The mould is cooled and the articles may be ejected by a blast of air from a pipe 71. A feed hopper 67 pivoted at 70<SP>1</SP> on the upper bolster 12 and at 68 on the container 24 is tilted automatically to feed position during descent of the bolster &c. Hydraulic rams 20<SP>1</SP> act upon the slides 16, 17 which carry the container, nozzle and mould segments 30.