US 4,657,718 AGranted

Coextrusion method

AssigneeThe Firestone Tire & Rubber Company

InventorsRichard W. Sicka, Dale A. Tompkins

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Abstract

A coextrusion head for producing a generally tubular elastomeric ply made up of first and second concentric tubular streams of elastomeric material having interposed, adjacent to their interface, a closely spaced array of parallel reinforcing elements wherein the coextrusion head includes a reinforcing element guide subassembly including a generally annular guide element as well as a mechanism for individually and independently directing and accurately positioning a circular array of uniformly spaced individual reinforcing elements. A generally annular inner die assembly cooperates with the annular guide element to form a first distribution channel and a generally annular outer die assembly also cooperates with the annular guide element to form a second distribution channel, with the guide element cooperating with the inner and outer die assemblies the produce concentric first and second tubular extrudate paths which thereafter merge into a third such path with the individual reinforcing elements being introduced into the interface between the first and second tubular streams of elastic material as they merge into a third tubular stream so as to produce the tubular elastomeric reinforced ply. A method for coextruding an annular seamless component of reinforced elastomeric material is also presented.

Claims14

Dependent claims

A method of coextruding an annular seamless elastomeric component made up of first and second independent coaxial juxtapositioned hollow layers of elastomeric materials having interposed, adjacent to their interface, a closely and uniformly spaced array of adjacent independent, and endless filament-type of reinforcing elements parallel to the direction of coextrusion, comprising the steps of:

(a) producing a first independently controlled annular hollow stream of elastomeric material within a coextrusion head;
(b) producing a second independently controlled annular hollow stream of elastomeric material concentric with said first stream, within said coextrusion head;
(c) producing, within said coextrusion head, a third annular hollow stream of elastomeric material, concentric with said first and second streams, by smoothly coaxially merging together said first and second streams, said third stream including, due to said merging, a common annular and concentric and merger interface between said former first and second streams;
(d) introducing into said coextrusion head a plurality of closely adjacent, independent and endless filament-type reinforcing elements in the direction of coextrusion;
(e) individually, totally enveloping each of said reinforcing elements within said coextrusion head and individually and independently directing said reinforcing elements to said third stream, via a closely spaced array of axially directed fixed guide means, in a closely, uniformly and circumferentially spaced annular array;
(f) accurately positioning said annular array of reinforcing elements at and substantially coaxial with said merger interface;
and
(g) interposing said annular array of reinforcing elements into said third stream, at said merger interface as it is produced, via the movement of said first and second streams for drawing said array of reinforcing elements into said merger interface, parallel to and synchronous with said third stream.

5 more elements

A method of producing annular seamless filament reinforced elastomeric body plies for use in manufacturing radial tires comprising the steps of:

(a) producing, within a coextrusion head and using a first extruder, a first annular hollow stream of elastomeric material having a circumferentially uniform wall thickness and velocity;
(b) producing, within said coextrusion head and using a second extruder, a second annular hollow stream of elastomeric material, concentric with said first stream, and having a circumferentially uniform wall thickness and velocity;
(c) producing, within said coextrusion head a third annular hollow stream of elastomeric material from and concentric with said first and second streams by smoothly merging together said first and second streams, said third stream due to said merging having a common, annular and concentric stock junction between said previous first and second streams, with the velocities of each of said first and second streams, at said merging step, being substantially similar;
(d) introducing into said coextrusion head a plurality of adjacent independent and endless filament type reinforcing elements in the direction of coextrusion;
(e) individually, totally enveloping of said reinforcing elements within said coextrusion head;
(f) individually and independently directing said reinforcing elements to said third stream, via a closely spaced array of axially directed fixed guide means, in a closely, uniformly and circumferentially spaced annular array;
(g) accurately positioning said annular array of reinforcing elements at said stock junction;
(h) interposing said annular array of reinforcing elements into the said third stream, at said stock junction as it is produced, via the movement of said first and second streams for drawing said array of reinforcing elements into said stock junction, parallel to and synchronous with said third stream, thereby producing a continuous annular seamless filament reinforced elastomeric component;
and
(i) sequentially circumferentially severing said annular seamless component, as it emanates from said coextrusion head, into predetermined lengths for use as body plies in manufacturing radial tires.

7 more elements

A method of producing sheets or strips of filament reinforced elastomeric material comprising the steps of:

(a) producing, within a coextrusion head, a first independently controllable annular hollow stream of elastomeric material;
(b) producing, within said coextrusion head, a second independently controllable annular hollow stream of elastomeric material, concentric with said first stream;
(c) producing, within said coextrusion head, a third annular hollow stream of elastomeric material, concentric with said first and second streams, by smoothly coaxially merging together said first and second streams, said third stream, due to said merging having a common annular and concentric merger interface between said former first and second streams, with said first and second streams each having a circumferentially uniform wall thickness and velocity at said merger step;
(d) introducing into said coextrusion head a plurality of closely adjacent, independent and endless filament-type reinforcing elements in the direction of coextrusion;
(e) individually, totally enveloping each of said reinforcing elements within said coextrusion head and individually and independently directing said reinforcing elements to said third stream, via a closely spaced array of axially directed fixed guide means, in a closely, uniformly and circumferentially spaced annular array;
(f) accurately positioning said annular array of reinforcing elements at said merger interface and substantially coaxial therewith;
(g) interposing said annular array of reinforcing elements into said third stream, at said merger interface, as it is produced, via the movement of said first and second streams for drawing said array of reinforcing elements into said merger interface, parallel to and synchronous with the longitudinal axis of said third stream, thereby producing a continuous annular seamless filament reinforced elastomeric component;
and
(h) longitudinally severing said annular elastomeric component, as it emanates from said coextrusion head, into one or more sheets or strips.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/807,076Filed 9 Dec 1985 · division
Priority: 22 Feb 1985
Granted: 14 Apr 1987
Term ends: Not estimatedThe source records don’t support an estimate.

Classification19 codes

B29D 30/0681
Pneumatic tyres or parts thereof: parts of pneumatic tyres; accessories, auxiliary operations
B29C 48/05
Characterised by the shape of the extruded material at extrusion: filamentary, e.g. strands
B29C 48/09
Characterised by the shape of the extruded material at extrusion: articles with cross-sections having partially or fully enclosed cavities, e.g.…
B29C 48/15
Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor:…