GB415062A - Improvements in or relating to injection moulding presses - Google Patents

Abstract

415,062. Injection-moulding machine. DANIELS, Ltd., T. H. & J., and DANIELS, J. S., Lightpill Iron Works, Stroud, Gloucestershire. Feb. 15, 1933, No. 4683. [Class 87 (ii).] A moulding press wherein thermoplastic material such as cellulose acetate is fed into a cylinder E<1> and thence forced by a plunger F through an injection nozzle E into a two-part mould or die comprises a pla,- ten C for carrying the lower mould part and moved by tension rods B<4> and a second platen D carrying the other mould part and slidable on the rods B<4> with limited movement away from the nozzle E, such that the rods bring the lower mould part against the other part and move them both in unison against a bridge-piece Ax fixed on the frame and with the nozzle E located in an admission gate D' in the platen D. The cylinder E<1> is carried by a platen E<2> slidable on the rods B<4> on the other side of the bridgepiece, being normally held against the bridgepiece by gravity or by a spring. The tension rods are operated through compression springs B<5> from eccentrics B<3> on a shaft B<2> driven through a clutch Bx by gearing from a drive shaft A<1>. The plunger F is operated through a spring F<2> from an eccentric F' on a gear wheel B<1> driven by the shaft B<2> through a clutch B<1x>. The clutch Bx operates for half a revolution of the shaft B<2> and the clutch B<1x> for a complete revolution, the clutches being operated from rods G<1>. G<2> through mechanisms interconnected so that the plunger cannot be operated when the mould is open. In operation the clutch Bx is actuated to draw the rods B<4> to close the mould parts together against the nozzle E. A feeding hopper E<1x> is filled with material and then the clutch B<1x> is actuated to move the plunger F down to inject the material into the mould and then withdraw the plunger, the tension rods and springs meanwhile maintaining the mould closed. The clutch B<x> is then again actuated to open the mould. The descent of the plunger can be adjusted by a micrometer screw device F<3>. The position of the platen C on the rods can be adjusted by worm gearing so as to accommodate different moulds. The movement of the platen D is limited by headed studs ax. The hopper E<1>w may be filled from a shoot H<5>, Fig. 5, supplied from a hopper H<4> by an intermittently operated rotary drum H having radial division plates H<1> or by a continuously or intermittently operated Archimedean screw or worm. The rotary drum may be driven by a pawl and ratchet device from a rod H<6> having tappets H', H<8> adapted be engaged by an arm F<4> on the plunger F. If there is sufficient material in the hopper E<1x>, the plunger does not move down far enough for engagement with the tappet H<8> and no feed of the drum takes place, so that material is fed only when required.