Patent GB-1446642-A (GB)
Title: Tyre carcass
IPC: B60C15/00
Filed: 1973-09-05
Abstract: 1446642 Pneumatic tyres; tyre-building apparatus STEELASTIC CO 5 Sept 1973 [26 Oct 1972] 41832/73 Heading B7C Pneumatic tyres.-The carcass of a pneumatic tyre, Fig. 10, has a body portion 79 reinforced by two body plies 99, 100 each having reinforcing means of the two plies being mutually axially spaced in the bead regions of the carcass but converging and lying at substantially the same radius in the region 101 of the carcass radially most remote from the bead regions, each bead region of the carcass incorporating at least one (as illustrated three) bead ring 81 associated with a flipper 82, the reinforcing means in each of body plies 99, 100 having generally radially inwardly directed ends secured to, and in overlapping juxtaposition with, one of said flippers. The invention is said to provide for the transfer of forces between the reinforcing means of the body plies and the bead rings without the necessity for looping the body plies around the bead rings. The body plies 99, 100 are each made from a plurality of axially extending strips (as more fully described below in relation to the tyre building apparatus) which may abut or overlap in the circumferential direction of the carcass. The reinforcing means of the body plies 99, 100 may take the form of wire filaments each following a helical path and extending generally radially of the carcass. The flippers 82 comprise elastomeric material which may be reinforced in a similar manner to the body plies 99, 100. Figs. 3 and 8 (not shown) depict carcasses not in accordance with the invention and provided respectively with a single body ply and two bead rings in each bead region (Fig. 3), and with a single body ply and a single bead ring in each bead region (Fig. 8). The carcasses may include protective chafer strips 86, Fig. 10. Tyre building apparatus.-An apparatus 10, Figs. 1 and 2, for building tyres having carcasses as described above, comprises collapsible tyre building drums 30, Fig. 2, movable to stations 30A, 30B, 30C, and 30D, Fig. 1, by means of a caroussel hub 25, a means 35 for transferring reinforced elastomeric ribbon 11 on to a drum at the station 30B, and a guillotine 45 for cutting a strip 61 to a desired length. In use a liner 88, chafer strips 86, and bead assemblies 80 are positioned on an expanded drum at the station 30B. A spindle 28 of the drum is engaged by a plunger 90 which serves to rotate the drum about its axis 31. Successive strips 61 of ribbon 11 are deposited on the drum. The ribbon 11 is supported by a lead-in mechanism 12 comprising a table 16 vertically movable by means of a cylinder 18, and side plates 14, 15. The ribbon is gripped and moved to a position above the drum by the means 35 which comprises a shuttle head 46 which may be moved horizontally by means of a cylinder 49, and which may be moved vertically by means of a cylinder 55. The shuttle head has apertures 96, Fig. 2, and a plenum chamber 94 which may be maintained at a subatmospheric pressure to hold the ribbon to the lower face 93 of the shuttle head by suction. The guillotine 45 comprises a fixed blade 68 and a blade 69 vertically movable by means of a cylinder 70.