GB1560920A

GB1560920A - Building a belted tyre

Info

Publication number: GB1560920A
Application number: GB1976277A
Authority: GB
Original assignee: Goodyear Tire and Rubber Co
Current assignee: Goodyear Tire and Rubber Co
Priority date: 1976-06-17
Filing date: 1977-05-11
Publication date: 1980-02-13
Also published as: FR2354874B1; IT1077306B; FR2354874A1; DE2726399A1

Description

(54) BUILDING A BELTED TIRE (71) We, THE GOODYEAR TIRE & RUB BER COMPANY, a corporation organized and existing under the laws of the State of Ohio, United States of America, of 1144 East Market Street, Akron, Ohio, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to method and apparatus for building belted tires and particularly for radial tires.

Heretofore, the belt has been assembled or built on a cylindrical drum apart from the carcass of the tire and then transferred as an assembled unit to a position surrounding the radial ply carcass, after which the carcass is expanded into circumferential contact with the belt. The belt then, after having been united with the carcass, is required to assume a curvature at least approximating to the curvature of the toriodally shaped inflated carcass.

We have discovered that by preforming this curvature by the method, and the ap paratus, of the present invention, an improved and more satisfactory tire can be produced.

The present invention provides in one aspect a method of building a tire having a circumferentially extending inextensible belt disposed about a toroidally shaped carcass ply, which comprises providing a carcass ply; providing a rigid building form having an axis, a centerplane normal to said axis, and a circumference in said plane equal to the circumference of the shaped carcass ply at its centre plane and an arcuate surface contour in an axial plane substantially the same as the contour of said belt in the com- pleted tire; wrapping successively a plurality of belt plies one at a time about the form and conforming each one to said contour before wrapping the next ply therearound; radially collapsing the form and removing the contoured assembly of belt plies from the form; disposing the assembly around the uninflated carcass ply: and expanding said carcass ply to a toroidal shape in the contoured belt assembly.

In a second aspect the invention provides a tire building form for building a belt assembly for a belted tire having a toroidally shaped carcass, the form comprising a multiplicity of axially extending rigid segments, means mounting the segments in circumferential array about an axis, and means for moving the segments radially of the axis, and each of said segments having an arcuate contour symmetrical about a centerplane of the form.

To acquaint persons skilled in the arts most closely related to the present invention, certain preferred embodiments thereof illustrating the best mode now contemplated for putting the invention into practice are described herein with reference to the annexed drawings forming a part of this specification. The embodiments shown and described herein are illustrative and as will become apparent to those skilled in these arts can be modified in numerous ways within the scope of the invention defined in the claims.

In the drawings: Figure 1 is a schematic view in cross-section of a tire building form in accordance with the invention; Fig. 2 is a schematic partial elevation in axial cross-section viewed as indicated by the line 2-2 of Fig. 1; Fig. 3 is a synoptic view illustrating the operation of transferring the assembled belt into its surrounding relation with the carcass.

The tire building form 10, Figs. 1 and 2, includes a multiplicity of arched segments 12 arranged in a circumferential array about the axis. Each of the segments 12 is attached at its respective axial ends 12' to segment carriers 16 which provide means for mounting the segments in the circumferential array. The carriers are movable radially of the axis by any convenient means therefor.

The individual segments 12 can be of any suitable rigid material. Hard wood has proved satisfactory in the building form 10 of Figs. 1 and 2, but the segments can also be made of a light metal such as aluminum, or of a rigid plastic.

To facilitate rapid interchange of the segments to accommodate the radius of curvature of the contour of the carcass of tires of different styles and size, the segments are attached to the segment carriers by a single flathead screw 18 at each end. Equivalent fastening means will be readily apparent to persons skilled in the art.

To hold successive belt plies as they are conformed to the compound curvature of the form 10, the surface of each segment has a coextensive cover of flexible magnetic tape 20 thereon. A suitable magnetic tape is obtained from Bunting Magnetics Company of Elks Grove Village, Illinois, and adhesively secured to the respective segment by a Mack Bond No. 0701 double-coated polyester tape, supplied by Morgan Adhe sive Company of Stow, Ohio.

The belt plies are of steel wire in the tire T and are thus held satisfactorily by the magnetic tape 20. For non-magnetic belt materials, other means for holding the belt plies on the form 10 can readily be substituted.

A circumferentially inextensible belt 30 for a tire T is built or assembled on a building form having an arched contour substantially the same as the contour of the shaped carcass ply of the tire to be built. In the building form 10 of Figs. 1 and 2, the arched segments having a contour appropriate to the tire being built are selected and affixed to the segment carriers 16, which are moved radially of the axis to establish a circumference at the mid plane 31 equal to the circumference of the shaped carcass ply in the tire 33. Individual belt plies 30a, 30b are then wound one at a time about the form 10 and are conformed individually, as by stitching, to the contour of the circumferential array of segments, each ply being conformed before the next succeeding ply. The next ply is then wrapped about that or those already in place on the form and conformed to the contour in like manner.

The term "equal" is applied in the present specification to the relation between the circumference of the belt building form and the circumference of the toroidallv shaped carcass and of the endless belt. It will be readilv apparent to persons skilled in the art that the relation is a practical one and that reasonable manufacturing deviations or tolerance from metrical identity are intended.

ODtionally, but preferably, a length of preformed tread stock 37 is then wrapped about the assembled belt 30 on the form and the tread too is stitched to conform it to the contour of the belt on the form.

When the belt or belt and tread assembly is complete on the form 10, the segments 12 are moved radialy toward the axis 14 a distance sufficient to release the assembled belt, and the belt or belt and tread assembly are moved from the building form into surrounding relation with the tire carcass 33 which is then expanded in a known manner to its toroidal shape and into circumferential contact with the contoured belt.

Referring again to Fig. 2, representative belt plies are indicated in phantom lines to emphasize that the plies as received from the server (not shown) are flat and are then formed progressively into conformity with the contours of the individual segments individually and successively.

The particular advantage of the present method, and apparatus, arises from the fact that, when heretofore the belt was built complete on a cylindrical drum without a contoured surface, stresses were introduced between the respective plies as that belt assumed the curvature of the tire carcass. In accordance with the present invention, on the contrary, each ply making up the assembled belt conforms to the compound curvature of the building form and thus the previously experienced interply stresses are minimized or completely eliminated before the belt assembly is applied to the carcass.

It has been found as a result that a more satisfactory radial ply belted tire can be made by the method and apparatus of the present invention.

WHAT WE CLAIM IS:- 1. A method of building a tire having a circumferentially extending inextensible belt disposed about a toroidally shaped carcass ply, which comprises providing a carcass ply: providing a rigid building form having an axis, a centerplane normal to said axis, and a circumference in said plane equal to the circumference of the shaped carcass ply at its centre plane and an arcuate surface contour in an axial plane substantially the same as the contour of said belt in the completed tire; wrapping successively a plurality of belt plies one at a time about the form and conforming each one to said contour before wrapping the next ply therearound; radially collapsing the form and removing the contoured assembly of belt plies from the form: disposing the assembly around the uninflated carcass ply; and expanding said carctss ply to a toroidal shape in the contoured belt assembly.

2. A method as claimed in Claim 1, and after completing said belt on said form, superposing a tread circumferentially about said belt and conforming the tread to the contour of the belt on the form and then transferring the tread together with the belt onto the uninflated carcass ply.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. of Figs. 1 and 2, but the segments can also be made of a light metal such as aluminum, or of a rigid plastic. To facilitate rapid interchange of the segments to accommodate the radius of curvature of the contour of the carcass of tires of different styles and size, the segments are attached to the segment carriers by a single flathead screw 18 at each end. Equivalent fastening means will be readily apparent to persons skilled in the art. To hold successive belt plies as they are conformed to the compound curvature of the form 10, the surface of each segment has a coextensive cover of flexible magnetic tape 20 thereon. A suitable magnetic tape is obtained from Bunting Magnetics Company of Elks Grove Village, Illinois, and adhesively secured to the respective segment by a Mack Bond No. 0701 double-coated polyester tape, supplied by Morgan Adhe sive Company of Stow, Ohio. The belt plies are of steel wire in the tire T and are thus held satisfactorily by the magnetic tape 20. For non-magnetic belt materials, other means for holding the belt plies on the form 10 can readily be substituted. A circumferentially inextensible belt 30 for a tire T is built or assembled on a building form having an arched contour substantially the same as the contour of the shaped carcass ply of the tire to be built. In the building form 10 of Figs. 1 and 2, the arched segments having a contour appropriate to the tire being built are selected and affixed to the segment carriers 16, which are moved radially of the axis to establish a circumference at the mid plane 31 equal to the circumference of the shaped carcass ply in the tire 33. Individual belt plies 30a, 30b are then wound one at a time about the form 10 and are conformed individually, as by stitching, to the contour of the circumferential array of segments, each ply being conformed before the next succeeding ply. The next ply is then wrapped about that or those already in place on the form and conformed to the contour in like manner. The term "equal" is applied in the present specification to the relation between the circumference of the belt building form and the circumference of the toroidallv shaped carcass and of the endless belt. It will be readilv apparent to persons skilled in the art that the relation is a practical one and that reasonable manufacturing deviations or tolerance from metrical identity are intended. ODtionally, but preferably, a length of preformed tread stock 37 is then wrapped about the assembled belt 30 on the form and the tread too is stitched to conform it to the contour of the belt on the form. When the belt or belt and tread assembly is complete on the form 10, the segments 12 are moved radialy toward the axis 14 a distance sufficient to release the assembled belt, and the belt or belt and tread assembly are moved from the building form into surrounding relation with the tire carcass 33 which is then expanded in a known manner to its toroidal shape and into circumferential contact with the contoured belt. Referring again to Fig. 2, representative belt plies are indicated in phantom lines to emphasize that the plies as received from the server (not shown) are flat and are then formed progressively into conformity with the contours of the individual segments individually and successively. The particular advantage of the present method, and apparatus, arises from the fact that, when heretofore the belt was built complete on a cylindrical drum without a contoured surface, stresses were introduced between the respective plies as that belt assumed the curvature of the tire carcass. In accordance with the present invention, on the contrary, each ply making up the assembled belt conforms to the compound curvature of the building form and thus the previously experienced interply stresses are minimized or completely eliminated before the belt assembly is applied to the carcass. It has been found as a result that a more satisfactory radial ply belted tire can be made by the method and apparatus of the present invention. WHAT WE CLAIM IS:-

1. A method of building a tire having a circumferentially extending inextensible belt disposed about a toroidally shaped carcass ply, which comprises providing a carcass ply: providing a rigid building form having an axis, a centerplane normal to said axis, and a circumference in said plane equal to the circumference of the shaped carcass ply at its centre plane and an arcuate surface contour in an axial plane substantially the same as the contour of said belt in the completed tire; wrapping successively a plurality of belt plies one at a time about the form and conforming each one to said contour before wrapping the next ply therearound; radially collapsing the form and removing the contoured assembly of belt plies from the form: disposing the assembly around the uninflated carcass ply; and expanding said carctss ply to a toroidal shape in the contoured belt assembly.

3. A tire building form for building a

belt assembly for a belted tire having a toroidally shaped carcass, the form comprising a multiplicity of axially extending rigid segments, means mounting the segments in circumferentially array about an axis, and means for moving the segments radially of the axis, and each of said segments having an arcuate contour symmetrical about a centerplane of the form.

4. A tire building form as claimed in Claim 3, having conformable magnetic tape adhered to the contour of each of said segments.

5. A method of building a tire having a circumferentially extending belt disposed about a toroidally shaped carcass ply, substantially as described with reference to the drawing.

6. A tire building form for building a belt assembly for a belted, tire, substantially as described with reference to and as shown in Figures 1 and 2.