GB839577A - Press for the manufacture of mass produced articles from hardenable plastics - Google Patents

Abstract

839,577. Moulding bottle screw caps. BUSS, W. Jan. 3, 1957 [Jan. 3, 1956], No. 367/57. Class 87(2). Mass-produced articles, for example bottle screw caps, are compression-moulded from hardenable plastic materials, e.g. phenol resins, in a press in which the refilling of the moulds with plastic material cannot take place until the previous moulding operation has been completed, whereby the moulds are not overfilled with plastic material. The apparatus comprises a plurality of pairs of dies which are similar, the description of one applying to all. With the lower die 3 in its bottom position a feed slide member 8, 9 advances to feed a measured quantity of plastic material, e.g. a phenol resin, from a container 12 through a shoot 13 to the lower die 3. A projection on the member 8 pushes forward a shutter 10 which prevents the accidental admission to the mould of more than the measured charge, e.g. following incomplete travel of the lower die which, however, retracts the shutter, if it reaches the top of its stroke, by meeting a bell crank 11. Each die is heated by an element 5. When the bottle cap has been compression moulded the lower die descends and a spring- actuated flap 15 moves through an opening in the moulding cylinder 2, ready to receive the cap as it is unscrewed from the top die by a rotating rubber roller 14. On the upward movement of the piston 3 the flap 15 ejects the article. The dies and associated mechanism are simultaneously actuated from a crossmember 18 which is vertically reciprocated by cam discs 16, acting on rollers 19 on the upstroke and on rollers 20 on the down stroke. The cam disc drives are geared together through gears 17 and driven from a gear wheel 21. Screw adjustment 23, 25 is provided between the cross-member 18 and each die 3, with cushioning springs 24.