Method and apparatus of forming extruded article
OwnerJames V. Dandeneauinventor
Life of this patent
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Abstract
An article such as a length of plastic tubing is integrally formed by melt extrusion and having opposite ends which in turn are provided with different flexibilities. The apparatus and extrusion method by which such articles are forming in a running length includes a gear assembly rotatable between at least two alternate positions whereby two different but mixable resins are alternatively extruded as product.
Claims15
The method of extrusion forming an article in the form of a continuous elongated strand wherein finite length portions of said strand form the article and the article has first and second terminal end portions formed of compatible first and second melt mixable plastics exhibiting differing physical properties and an intermediate connecting portion formed of a melt extrusion blending of the first and second plastics connecting the end portions, comprising, continually extruding both said first and second plastics from separate extrusion sources to an extrusion head having a downstream longitudinally directed common article extrusion path and separate upstream longitudinally directed first and second dump extrusion paths so as to direct said first plastic through said article extrusion path for subsequent cooling and processing to form said article while simultaneously laterally directing said second plastic through said second dump path to waste and thereafter intermittently and in timed sequence quickly redirecting the extrusion paths of said first and second plastics so as to longitudinally direct said second plastic through said article extrusion path and said first plastic laterally through said first dump path.
Apparatus for forming an article in the form of a continuous elongated strand wherein finite length portions of said strand form the article and the article has first and second terminal end portions formed of compatible first and second melt mixable plastics exhibiting differing physical properties and an intermediate connecting portion formed of a melt extrusion blending of the first and second plastics connecting the end portions, comprising, a pair of extruders connected to a common extrusion head in turn having a downstream longitudinally directed common article extrusion path and separate upstream first and second dump extrusion paths, said first and second dump extrusion paths each comprising a first upstream longitudinally directed sector substantially parallel to said common article extrusion path and a second downstream laterally directed sector open to waste, said first sector of each said dump extrusion path and said common extrusion path comprising an overall longitudinally directed composite path through which said article is extruded, and rotational means in said head for quickly directing and redirecting said first and second plastics from said extruders sequentially from said article extrusion path to one said dump paths and vice versa.
Dependencies are inferred from the claim text.