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US 4,056,344 AGranted
Apparatus for producing composite extrusions
OwnerJerome H. Lemelsoninventor
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OwnerJerome H. Lemelsoninventor
Estimating the term…
An apparatus and method are provided for producing extrusions of two or more materials such as plastic polymers so as to utilize the characteristics of both materials in a single formation thereof. In one form, flexible and rigid polymers are coextruded through a common die to form selected portions of the length of an extrusion or to form portions of the length of an extrusion composed of one polymer and other portions composed of the same polymer plus a second polymer. Tubing may be formed having portions of its length made completely of a flexible polymer and other portions thereof made of a rigid polymer. The apparatus mahy also form rigid pipe having elastomeric material coated or extruded along selected lengths thereof such that when severed along said lengths, selected pipes may be formed thereof containing end seals formed integral with each length.
An apparatus for forming an integrally molded article of at least two different thermoplastic materials comprising:
An extrusion apparatus comprising an extruder having a die containing an opening, a mandrel disposed in said die opening, a first means associated with said die for variably forcing a first extrusion material through said die opening and over said mandrel to form a tubular extrusion thereof a second means operatively associated with said die for variably forcing the flow of a second extrusion material and causing said second material to combine with said first extrusion material along selected portions of the length of said tubular extrusion formed of said first material and to form tubular formations of said second extrusion material along selected portions of the extrusion so as to define a composite tubular extrusion formed primarily of said first extrusion material and having circumscribing portions of its wall composed of said second extrusion material at predetermined intervals along its length,
Dependencies are inferred from the claim text.