Apparatus for injection molding against a preformed web
AssigneeImperial Chemical Industries PLC
InventorBerwyn C. Thomas
Life of this patent
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Abstract
Apparatus for injection-moulding articles of plastics material onto a preformed web inserted into the mould, the web is held under substantially constant tension during the closing of the mould, between a pair of clamps, the proximal clamp being fixed relative to the mould and the distal clamp free but bearing a load to furnish the desired tension in the web. The load may be imposed by a weight attached to the distal clamp, conveniently by means of an electromagnet.
Claims8
Apparatus for injection moulding thermoplastics material onto a preformed web paid out so as to pass between closable core and cavity components of an injection mould and so as to have a free distal end protruding below the mould components, and a proximal portion above the mould components, said apparatus comprising:
- an injection mould having closable core and cavity components;
- engaging means for engaging a load on the free distal end of the preformed web protruding below the mould components;
- a load engageable on a said distal end by the engaging means, the load being free to move with a distal end on which it is engaged;
- and holding means located above and fixed relative to the mould components for holding a proximal portion of a web against a load engaged on a distal end of the web below the mould components, whereby when the mould components are closed onto a preformed web located between the components they cause a free distal end of a web protruding below the components to move in response to the closing of the mould whereupon the load attached to such a distal end moves with the distal end and controls the tension in the web during the closing of the mould.
Dependencies are inferred from the claim text.