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US 4,086,045 AGranted
Apparatus for the manufacture of thin-walled shaped articles of thermoplastic material
AssigneeBellaplast GmbH
InventorsAlfons W. Thiel, Hans Hell
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AssigneeBellaplast GmbH
InventorsAlfons W. Thiel, Hans Hell
Estimating the term…
Thin-walled articles of thermoplastic material are formed in a continuous apparatus starting with heating and extruding granular thermoplastic raw material in the form of a continuous web which is immediately stabilized by rapid cooling of its opposite surfaces and the stabilized web wherein the material sandwiched between the precooled outer surface layers remains at or near extrusion temperature is fed into a thermal forming station wherein shaping tools form the articles in the web without the need for further heating of the web. Adjustments are provided for correlating the cooling action to different materials and web feed rates, for varying the web feed rates and increments, and for varying the shaping tool movements to adapt for different materials and sizes of articles. After the formed articles are separated from the web the web residue is fed back to be mixed with incoming raw material at the extrusion station.
Apparatus for manufacturing thin-walled synthetic plastic articles which comprises extrusion means for forming a continuous hot plastic web of thermoplastic material at a predetermined high temperature, means for substantially immediately stabilizing said web to self supporting condition by cooling opposite surfaces of the web to provide therealong continuous outer supportive layers that are sufficiently deformable for shaping in subsequent shaping tool operation while the hot plastic material between said layers remains sufficiently plastic and fluid for redistribution between said layers during said tool operation, and means for advancing the stabilized web toward and into a thermal forming station in synchronism with shaping tools in said station adapted for forming articles in successive areas of said web during the period that said hot plastic material between the layers remains capable of redistribution between them.
The apparatus defined in claim 9, wherein temperature distribution is effected by means providing proportional reflection of radiant heat from the hot plastic web.
Apparatus for manufacturing thin-walled synthetic plastic articles which comprises means including extrusion means for forming a continuous plastic web of thermoplastic material at a selected high temperature and means for substantially immediately stabilizing said web to self supporting condition by cooling opposite surfaces of the web to provide therealong continuous outer supportive layers that are sufficiently deformable for shaping in subsequent shaping tool operation while the hot plastic material between said layers remains sufficiently plastic and fluid for redistribution between said layers during said tool operation, and means for advancing the stabilized web toward and into a thermal forming station wherein successive areas of the web are subjected to the action of shaping tool means, said web advance being effected at such speed and in such timed relation to operation of the shaping tool means and in such correspondence with the web extrusion temperature that said stabilized web arrives at said thermal forming station while it retains sufficient heat in its inner core portion to partially reheat its cooled surface layers by heat conduction from the inner core portion outwardly during transport from said stabilizing means to said thermal forming station so that said layers are elastically deformable for improved shaping.
Dependencies are inferred from the claim text.