US 4,285,651 AGranted

Extrusion die head and method of making the same

AssigneeThe General Tire & Rubber Company

InventorsDavid C. Fetchu, William H. Weidman

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Abstract

A new extrusion die head and method of making the same is provided that permits two strips of elastomeric material to be extruded simultaneously and one above the other from a single core of extrudate. The head is particularly useful for extruding sidewall strips in the manufacture of pneumatic tires. The head design has features common to both conventional strip extruding heads and to heads for extruding tubular shapes, commonly called tuber heads. However, the head is quite different from both the conventional strip extrusion heads and the conventional tuber heads, and has the advantage that it permits two strips to be extruded simultaneously through passages that are relatively short in length and are no wider than the width of a single sidewall strip. The design of the head and the method of making it are such that the extrusion passage surfaces can be easily machined to provide excellent flow characteristics, and the entire head is easily fabricated and cleaned.

Claims13

Dependent claims

An extrusion die head for forming two elongated strips of elastomeric material from a core of said material emanating from a single bore in an extruder, said extrusion die head having an inboard end to be located facing toward said extruder and an outboard end to be located facing away from said extruder, said extrusion die head including an outer head section having a central opening extending from said inboard end to said outboard end, an inner head section located within said central opening and spaced from the walls of said central opening so as to define two separate passages for guiding the flow of said elastomeric material through said head, characterized in that:

(a) said outer head section includes a ring member having a central axis and extending from said inboard end to said outboard end of said extrusion die head, said ring member having a radially inwardly facing conical surface, said inwardly facing conical surface having a relatively small diameter at said inboard end of said extrusion die head and a relatively large diameter at said outboard end of said extrusion die head,
(b) said outer head section also includes first and second cone members each having on one side a radially outwardly facing conical surface mating with the radially inwardly facing conical surface of said ring member and on the opposite side a flow passage surface forming one of said walls of said central opening, and
(c) said inner head section includes a middle cone member disposed between said first and second cone members and extending across said central opening to divide said central opening into said two separate passages, the side edges of said middle cone member being radially outwardly facing conical surfaces that mate with the radially inwardly facing conical surface of said ring member, the top and bottom sides of said middle cone member each facing one of said flow passage surfaces of said first and second cone members forming therewith one of said passages for guiding the flow of said elastomeric material through said head, thereby forming said elastomeric material into a desired strip shape as said material passes from said inboard end to said outboard end of said extrusion die head.

A method of making an extrusion die head for forming two elongated strips of elastomeric material from a core of said material emanating from a single bore in an extruder, characterized by the steps of;

(a) fabricating a ring member and machining on said ring member a radially inwardly facing conical surface,
(b) fabricating a conical piece with an outboard end surface and an axially extending surface intersecting said outboard end surface, and machining said axially extending surface to form a radially outwardly facing conical surface that mates with said radially inwardly facing conical surface of said ring member,
(c) cutting said conical piece into three cone members along two cutting planes that intersect said base surface,
(d) machining the cone member surfaces that extend along said cutting planes to a configuration such that when said cone members are mounted with their radially outwardly facing conical surfaces engaging the mating radially inwardly facing conical surface of said ring member, the said surfaces extending along said cutting planes form two extrusion passages of the desired shape for guiding and forming said elongated strips of elastomeric material, and
(e) reassembling and mounting said cone members within said ring member with said radially outwardly facing conical surfaces of said cone members engaging said mating radially inwardly facing conical surface of said ring member and positioned so as to form said two extrusion passages of said desired shape.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/121,942Filed 15 Feb 1980
Granted: 25 Aug 1981
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

B29C 48/345
Extrusion nozzles or dies: extrusion nozzles comprising two or more adjacently arranged ports, for simultaneously extruding multiple strands, e.g.…
B29C 48/07
Characterised by the shape of the extruded material at extrusion: flat, e.g. panels
B29C 48/30
Component parts, details or accessories; Auxiliary operations: extrusion nozzles or dies
B29C 48/305
Extrusion nozzles or dies: having a wide opening, e.g. for forming sheets