Method of producing a toroidal road vehicle tire carcass

Abstract: A toroidal road vehicle tire carcass (1) having two annular beads (2) connected by a toroidal reticulated structure (4) defined by a number of elongated reinforcing elements located between and extending substantially radially in relation to the beads (2) is formed from a single continuous cord (5) for forming a succession of U-shaped loops (6), each of which is wound about both beads (2) so as to form a tubular reticulated structure (4), and presents an open end (8) and a closed end (9) located and connected along an annular interconnection line (7) extending centrally in relation to the beads (2).

Description: The present invention relates to a method of producing a toroidal road vehicle tire carcass. More specifically, the present invention relates to a straightforward, low-cost method of producing a toroidal radial tire carcass comprising two annular beads connected by a toroidal reticulated structure in turn comprising a number of elongated reinforcing elements connecting and extending substantially radially in relation to the beads. According to EP-A-0 549 869, which is considered herein under the terms of Article 54(3) EPC, a road vehicle tire carcass, comprising two annular beads connected by a toroidal reticulated structure defined by a number of elongated reinforcing elements extending between and substantially radially in relation to the beads, is produced by using at least one continuous cord for forming a continuous series of oppositely orientated U-shaped loops, the loops in both series being so connected as to weave a substantially tubular structure enclosing the two beads. According to the present invention, there is provided a method of producing a toroidal road vehicle tire carcass comprising two parallel annular beads, and a toroidal reticulated structure connecting the two beads and comprising a number of elongated reinforcing elements located between and extending substantially radially in relation to the beads; said elongated reinforcing elements being formed from a single continuous cord wound in such a manner as to form a succession of U-shaped loops, each of which is wound about the two beads so as to form a tubular reticulated structure, and presents an open end and a closed end connected along an annular interconnection line extending in an intermediate position in relation to the beads. The present invention will now be described by way of example with reference to the accompanying drawings, in which: Fig.1 shows a schematic view in perspective of a portion of a carcass formed using the method according to the present invention; Fig.2 shows a spreadout view of the Fig.1 carcass portion. Number 1 in Fig.1 indicates a toroidal road vehicle tire carcass. Carcass 1 comprises two annular beads 2 with respective fillers 3; and a toroidal reticulated structure 4 connecting beads 2 and in turn comprising a number of reinforcing elements extending between and substantially radially in relation to beads 2. In the example shown, said reinforcing elements are formed from a single continuous cord 5 wound in such a manner as to form a succession of U-shaped loops 6 extending from an annular interconnection line 7. Line 7 lies substantially in a plane between the planes of beads 2, and, as in the example shown, is preferably located substantially centrally in relation to the planes of beads 2. Each loop 6 presents an open end 8 and a closed end 9, and is wound about both beads 2 and fillers 3 so as to form, together with the other loops 6, a substantially tubular structure 4. More specifically, each loop 6 is arranged with both ends 8 and 9 along line 7, and with open end 8 engaging closed end 9, so as to connect ends 8 and 9 by means of a succession of interconnections 10 along line 7. Moreover, along line 7, there extends a succession of cord portions 11, each connecting the open end 8 of one loop 6 to the open end 8 of the next loop 6. Carcass 1 as described above is preferably formed on a supporting frame 12 comprising an inner portion 13 defined by beads 2 and forming the skeleton of carcass 1; and a removable auxiliary outer portion 14 defined by two rings 15, each consisting, in known manner not shown, of a number of releasably-connected curved segments. Portion 14 is located between and radially outwards in relation to beads 2, so as to define, with beads 2, two annular openings 16. When forming structure 4, frame 12 is preferably rotated about its axis, and structure 4 is woven about beads 2 and outwards of portion 14. More specifically, each loop 6 presents an intermediate portion 17 extending between the two beads outwards of portion 14 and through one of openings 16; and two end portions 18 and 19, the first of which, adjacent to open end 8, extends outwards of openings 16, and the second of which, adjacent to closed end 9, extends through the other opening 16.

Claims: A method of producing a toroidal road vehicle tire carcass (1) comprising two parallel annular beads (2), and a toroidal reticulated structure (4) connecting the two beads (2) and comprising a number of elongated reinforcing elements located between and extending substantially radially in relation to the beads (2); said elongated reinforcing elements being formed from a single continuous cord (5) wound in such a manner as to form a succession of U-shaped loops (6), each of which is wound about the two beads (2) so as to form a tubular reticulated structure (4), and presents an open end (8) and a closed end (9) connected along an annular interconnection line (7) extending in an intermediate position in relation to the beads (2). A method as claimed in Claim 1, characterized by the fact that said continuous cord (5) is so wound that said interconnection line (7) is located substantially centrally in relation to the bead planes. A method as claimed in Claim 1 or 2, characterized by the fact that it comprises an initial stage consisting in forming a supporting frame (12) for the carcass (1); said frame (12) comprising an inner portion (13) defined by the two beads (2) and forming the skeleton of said carcass (1), and a removable auxiliary outer portion (14) located between and radially outwards in relation to the beads (2); said reticulated structure (4) being woven about the beads (2) and outwards of the auxiliary outer portion (14). A method as claimed in Claim 3, characterized by the fact that said inner and outer portions (13, 14) define two annular openings (16); each said loop (6) comprising an intermediate portion (17) extending between said two beads (2) and through one of said openings (16), and two end portions (18, 19), one of which extends through the other of said openings (16).

Inventors: SIEGENTHALER KARL J, SIEGENTHALER, KARL J.
Applicants: BRIDGESTONE CORP, BRIDGESTONE CORPORATION
Application year: 1993
Main classification: B29D30
IPC codes: B60C9, B29D30