Patent GB-620660-A (GB)
Title: Method and apparatus for building tires
IPC: B29D30/24
Filed: 1945-06-14
Abstract: 620,660. Pneumatic tyres. GENERAL TIRE & RUBBER CO. June 14, 1945, No. 15112. Convention date, June 14, 1944. [Class 144 (i)] Relates to means, of the kind described in Specification 614,162, for building a tyre cover by the flat-band process, comprising assembling a band of fabric with its edges overlapping the shouldered edges of the building-drum and then folded over applied bead-rings, assembling further plies (with their edges projecting beyond the beads) and tread rubber, the built-up cover being then compacted by radial pressure applied across the full width of the rotating drum, stitching the fabric plies to the outer faces of the beads, stopping the drum and folding the edges of the outer plies under the beads to which axial and radial pressures are then applied simultaneously throughout the full circumference. Fig. 1 shows the general lay-out of a machine comprising a collapsable building- drum A, fixed and movable bead-setting heads C, B, respectively, and tread-consolidating rollers 121, 122. Bead-building. As shown in Fig. 14, the devices for applying the beads comprise rings 24 coaxial with the drum-shaft and moved to and from the drum A by pressure-operated linkage-gear. Mounted within each of the rings 24 is a stepped ring 35 on which the beadring E with flipper F is assembled. The ring 35 is yieldingly carried with the ring 24 in its forward traverse until arrested by contact of the bead-ring with the folded-down edge of the fabric on the drum-head. Each ring 24 carries a smoothing-ring 40 in the form of a contractile endless coil-spring of normally less diameter than the drum so that, on further advance of the ring 24, the ring 40 expands into forcible engagement with the edge portion of the fabric on the drum periphery. For folding the edge of the fabric inwardly over the drum-shoulders, each head is provided with a coil-spring ring 42 carried by arms 43 which are actuated by toggle-mechanism 47, 48, 51 to cause the ring 42 to wipe down the overhanging edge portion of the 'fabric. After assembly of the bead-ring, the fabric flap between the drum-edge and the bead is folded axially and radially outwards over the bead by discs 64, 65, 66, each formed of radiallymovable segments mounted between a disc 63 and a retaining-plate 67. As the discs are moved axially, the segments are displaced radially, by linkage-gear 70, to expand and contract the discs in their (axially) outward and inward movements respectively. Figs. 21, 25, 26 show means for applying the tread rubber and consolidating the built-up cover. Rubber stock G is fed from a table 120 to the underside of the rotating drum A and consolidated by a set of pressure-rolls 121, 122, a pair of conical rolls 126 for operating on the shoulder portions P, and sets of stitcher-wheels 123, 124, 125 which operate on the edge portions of the fabric. The pressure-rolls comprise a central solid roll 122 profiled to operate on the concave portion m of the tread, and yielding side-rolls 121 for operating on the side-wall portions r of the tyre. The rolls 121 comprise laminated rings 128 supported on a soft rubber cushion 129. The pressure-rolls are carried on linked radiusarms 134, 136 and are raised into operative position by the ram 141 of a power-cylinder 142. The stitchers 123-5 are similarly moved by means of a power-cylinder 154. The shoulderpressing rolls 126 are carried on a pivoted hanger 160 which is connected by a chain 162 to a rocker 152 pivoted at 149 on the head of the ram 153.