Patent GB-1348254-A (GB)
Title: Reinforced fabric
IPC: B29C48/156
Filed: 1970-12-16
Abstract: 1348254 Seaming; extruding tyre fabrics STEELASTIC CO 16 Dec 1970 [6 Jan 1970] 59692/70 Headings B5A and B5K [Also in Divisions B7 and D1] A reinforced ribbon comprises an elastomeric matrix comprising a plurality of discrete single filament reinforcing wires, each of said filaments delineating a cylindrical helix. Each monofilament wire drawn from spools 66, Fig. 6, passes through a hollow spindle 52 in first orifice means 48, mounted on head plate 36, then through first diehead 50, mounted in eccentric chuck 51 for rotation about spindle axis 62, then through die head 63 in second orifice means 49, mounted on tail plate 39. The bevel 70 on bore 71 in spindle 52 restricts the cold-working into a helix to the region of dieheads 50, 63. The change in microstructure so produced stabilizes the helical configuration. The lateral separation 69 between the two orifice means depends upon the eccentricity of the chuck but 69 must exceed the-sum of the radii of bores 61, 64; the longitudinal separation depends upon that between plates 36, 39. The diameter of the helix is no greater than 3 times the filament diameter, and there are 1¢ to 3 leads (turns) per inch. The extension to elastic limit is not more than 5% and to failure 7À5%. Although helical wires 15 may be taken up on spools it is preferred to dry them in oven 67 and then incorporate them in an elastomeric matrix by passing them through extruder 31 or by calendering. The wires are in planar parallel array, alternate wires being of opposite helix. This alteration in twist is obtained by fitting each hollow spindle 52 with a spur gear (72, Fig. 8, not shown) so that each spindle is driven by one neighbour and drives another neighbour. In the first method of forming a bias cut tyre reinforcement strip 94, tape 30 is wound on rotating drum 75 which is displaced longitudinally by threaded rod 90. Alternatively the tape 30 is deposited by a travelling head. Overlapping edges of the tape are joined by the pressure of roller 89 to form a sheet. Rotation of carousel 80 brings the sheet into contact with cutting head 91 which is moved along rotating drum 75 to cut the sheet into a strip 94 in whch the helical wires 16 are aligned at an angle # of at least 4 degrees. On joining the biased end (95, 96, Fig. 12, not shown) of strip 94 a continuous belt (98) is formed. In the second embodiment tape 30 is extruded with inclined longitudinal edges 88 and is cut into lengths 110 by knife 109 at an angle # to the transverse axis of the tape. The lengths 110 are successively deposited on belt 113, which is advanced after each length is deposited, so that adjacent lengths 110 contact each other along their bevelled longitudinal edges 88. The transfer is accomplished by feed rolls 101, which slide the length 110 on to a receiving means 102 which comprises a support shelf (104, Fig. 15, not shown) resiliently supported by a spring arm (105). The downward movement of a plunger (111) presses edge 88 of the length 110 on shelf (104) into contact with the edge of the previously laid length and tilts the shelf so that the length 110 slides on to belt 113. In the preparation of a tyre two endless belts (98) of elastomer reinforced with helical filaments are applied with the reinforcing filaments 15 biased with respect to a radial plane (18, Fig. 1, not shown) perpendicular to the rotational axis of the tyre, the bias of the second filaments being opposite to those of the first The belts or breaker plies may be incorporated whilst the tyre is being built up on a drum or after it has been removed. Alternatively the tyre may incorporate a plurality of narrow reinforced elastomer strips (139a, 139b, &c. 140a, 140b &c., Fig. 17, not shown) arranged in two layers. This provides greater flexibility whilst the tyre is being formed and equal strength after the tyre has been vulcanized.