Patent ES-299519-A1 (ES)
Title: Method of making a tire using a fabric with contracted filaments or cords
IPC: B29D30/24
Filed: 1964-05-05
Abstract: Filamentary fabrics, especially fabrics consisting of parallel filaments or cords of nylon, cotton, rayon, polyester, glass or metal, with or without spaced wefts, are treated, particularly for use as breaker layers in tyres built initially in cylindrical form and subsequently expanded to toroid shape, by longitudinally compressing the filaments and adhering them before or after compression, and on one or both sides, to unvulcanized sheet rubber. In Fig. 1 a longitudinally extensible belt 2, rendered laterally inextensible by inserted steel cords 3, is driven by co-operating pairs of rollers 4, 5 and 6, 7, the former pair rotating faster than the latter, such that the belt is stretched on its lower flight and contracts on the upper flight. A web 15 of rubberized filaments is pressed into contact with, and contracted by, the upper flight and is then adhered to a web of unvulcanized rubber 10 by a driven roller 8. The combined webs are removed from the belt by a blade 11 and passed around a heated drum 12. The web 10 contains embedded longitudinal weak threads which hold the filaments of the web 15 in contracted condition during handling or storage but which are broken during expansion of the tyre of which the combined web forms the breaker layer. The web 15 may comprise a strip of bias-cut rayon cord fabric, folded longitudinally, and may after longitudinal contraction on the belt 2, be fed directly around a tyre-building roller, the drum 12 being dispensed with. In a modification a web such as 15, together with upper and lower webs of vulcanized rubber, is fed between upper and lower belts such as 2, the combined webs being contracted during passage between the adjacent contracting flights of the belts, and being rolled up for storage with a layer of polythene which retains it in contracted state. In a further modification, Fig. 8, a strip 43 of longitudinally extensible but laterally inextensible vulcanized rubber is clamped between plates 45, 48 and stretched by screw-and-nut mechanism 49, 50. A layer 52 of bias-cut rayon cord with or without layers of unvulcanized rubber, is laid on the stretched strip and is contracted on relaxing it, the contracted layer being held by application of unvulcanized rubber containing weak threads. The strip 43 may be wide enough to accommodate a length of bias-cut cord fabric laid across it the direction of laying being related to the bias-angle desired in the fabric as incorporated in the tyre. In another modification a cylindrical rubber sleeve which comprises an assembly former for breaker layers and which is axially extensible but rendered radially inextensible by incorporation of circumferential steel cords, is stretched axially, a stable strip of bias-cut rayon cord fabric is then wrapped around the former and the ends joined, and on releasing the extension is contracted such that, for example, cords originally lying at 55 degrees to the length of the strip then lie at 27 degrees. The contracted strip is then transferred to the tyre-forming apparatus. Apparatus, Fig. 4, for longitudinally folding longitudinally contracted bias-cut textile cord fabric 30 for use as a breaker layer comprises a drum the cylindrical surface of which is formed by arcuate segments 18 which can be moved radially up against stop flanges 22 by two inflatable rings 17. Rubber rings 19, 20 mounted side-by-side, surround the segments 18, ring 19 having peripheral grooves 24 connected to suction means, and the ring 20 being thinner and surrounded by an inflatable ring 27. With the segments 18 collapsed a strip 30 of contracted cord fabric is secured symmetrically on the drum and expanded by inflating the rings 17. Bag 17 is then inflated to raise one half of the fabric while the other half is held by suction. A sleeve 28 axially slidable on a frame 29 is then moved to a position covering the ring 19 thus causing the bag 27 to turn the right-hand half of the strip 30 over on to the left-hand half. The folded strip is transferred to the tyre-building apparatus by means comprising an axially movable hollow ring containing an inflatable annular bag which can be used to move a rubber ring beneath it radially inwardly and outwardly to grip the fabric layer adhesively, expand it, convey it to the coaxially mounted tyre-forming apparatus, and press it on to the tyre carcase.