Method of and apparatus for extrusion
AssigneeSouthwire Company
InventorRalph E. Starnes, Jr.
Life of this patent
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Abstract
A method of and apparatus for simultaneously extruding a coating comprising a plurality of layers of dissimilar plastic compounds having substantially different melting points onto a moving electrical conductor wherein the plastic compounds are mechanically and thermally separated. Separating the two plastics prevents thermal degradation of the two extrudates by causing their melt temperatures to remain substantially constant.
Claims42
Apparatus for extruding a coating comprising two layers of dissimilar plastic compounds having substantially different melting points onto an electrical conductor, comprising:
- a segmented head having first and second segments and having enlarged first and second end openings connected by a main axial bore smaller than the diameter of said end openings to provide inwardly disposed annular shoulders at the base of said openings, said bore extending through said first and second segments;
- a first passageway in said first segment for applying the plastic composition which comprises the inner layer of said coating to said electrical conductor;
- a second passageway in said second segment for applying the plastic composition which comprises the outer layer of said coating to said electrical conductor;
- segmented internal tooling having first and second segments for guiding and applying the plastic compositions which comprise the inner and outer layers of said coating to said conductor having a plurality of segments and having first and second end openings connected by a main axial bore, said bore extending through said plurality of segments;
- a means for passing an electrical conductor through said main axial bore of said internal tooling;
- a means interposed between said first and second internal tooling segments for thermally isolating said first segment from said second segment;
- a heat sink means interposed between said first and second internal tooling segments for removing excess heat flowing from the segment through which passes the higher melting point plastic composition and from the plastic composition flowing through said segment;
- a means for monitoring the temperature in said first and said second internal tooling segments;
- and
- a guide means for maintaining the position of said electrical conductor within said main axial bore of said internal tooling while said coating is applied to said conductor.
Passing an electrical conductor through an apparatus for extruding a coating comprising two layers of dissimilar plastic compounds, said compounds having substantially different melting points, onto said electrical conductor, comprising:
- providing a segmented head having first and second segments and having enlarged first and second end openings connected by a main axial bore smaller than the diameter of said end openings to provide inwardly disposed annular shoulders at the base of said openings, said bore extending through said first and second segments;
- applying the plastic composition which comprises the inner layer of said coating to said electrical conductor in a first passageway in said first segment;
- applying the plastic composition which comprises the outer layer of said coating to said electrical conductor in a second passageway in said second segment;
- guiding and applying the plastic compositions which comprise the inner and outer layers of said coating to said electrical conductor through segmented internal tooling having a plurality of segments and having first and second end openings connected by a main axial bore, said bore extending through said plurality of segments;
- passing said electrical conductor through said axial bore of said internal tooling;
- thermally isolating said first segment from said second segment utilizing a thermal isolation means;
- monitoring the temperature in said first and said second segments;
- removing excess heat flowing from said segment through which passes the higher melting point plastic composition and from said plastic composition flowing through said segment and through a heatsink means interposed between said first and second segments;
- maintaining position of said electrical conductor within said axial bore of said internal tooling while said coating is applied to said conductor by passing said conductor through a guide means adjustably positioned within said axial bore of said segmented head.
Dependencies are inferred from the claim text.