Patent GB-608597-A (GB)
Title: Tire building machine
IPC: B29D30/32
Filed: 1945-06-15
Abstract: 608,597. Pneumatic tyres. GENERAL TIRE & RUBBER CO. June 15, 1945, No. 15286. Convention date, Aug. 6, 1942. [Class 144 (i)] A method of building a tyre cover by the flat-band process on an openended drum, having an inwardlydirected radial flange at each edge, comprises turning the edge-portion of the laid-on ply-material over, and beyond, the drum flange, pressing a bead-ring against the material overlying the flange whilst the entire circumferential extent of the extending flap of ply-material is folded against the inner periphery of the bead-ring, the extending flap of material being folded to enclose the bead, and the superposed plies and tread element being then stitched down by devices operating, by a stroking action, around the full circumferential extent of the drum. The machine shown for carrying out the method comprises normally contractile rings for stitching the plymaterial (and the tread), means for expanding the rings for free movement over the drum, means for freeing the rings to contract on to the tyre material, and means for moving the stitcher-rings out of the path of the bead-ring assembly devices. After the first plies of tyre material have been laid around the drum, the operations of bead-assembly, folding the edge portions of the under plies over the bead and flipper-strip, stitching down the further plies of tyre material and. the tread are performed by means of mechanisms operated in timed sequence from a rotary cam. Apparatus described comprises a collapsible building- drum A mounted between, and co-axially with, (identical) mechanisms B, C for the beadsetting, folding, and stitching operations, one of those mechanisms being axially-movable to permit collapse of the drum for removal of the built-up tyre. Fabric folding and stitching. The main folder and stitcher elements consists of a pair of rings 9 which, as the operative movement, traverse the drum from its centre-line zone to, down, and under the edge portions of the assembled ply-material and beads. Each ring 9 consists of a series of coil springs 9a, Fig. 11, connected by plugs 10. The plugs are embraced by hooks 12 adjustably secured to radiallymovable levers 15 which are pivoted on a disc 18 slidable, to and from the drum on the main shaft 1. The ring 9, which is normally of smaller diameter than the drum, is expanded for assembly into operative position over the ply-material on the drum by means of a thrust ring 24, Fig. 5, engaging rollers 21 on pivoted links 20 which bear against crank-arms 19 on the levers 15. The ring 24 is actuated by rods 25 connected to a lever 26 carrying a roller 111 which engages a groove 116 in a composite controlling-cam 110. The axial movement of the ring 9 is effected by a disc 27 which is slidable on the shaft 1 by means of rods 35 projecting from a disc 27. The latter is connected by rods 28 to an actuating-lever 29 having a roller 112 engaging a groove 117 in the cam 110. An auxiliary device for folding the ply-material under the bead comprises a series of arcuate shoes 40 mounted in a disc 39 which is axially-movable within the edgeportion of the drum. The shoes 40 are forced radially outwards (into operative position) by an axially-movable coned disc 48 co-operating with taper heads 46 on spring-pressed bolts 41 on which the shoes 40 are carried. The synchronized and relative axial movements of the discs 39, 48 are effected by rods 50, 53 connected to actuating levers 52, 55 respectively, these levers having rollers 113, 114 engaging grooves 118, 119 respectively in the cam 110. Bead setting. After the first assembly of ply-material has been folded down to the position shown in Fig. 17, the bead ring, which is carried on an expansible spring-ring 63 is advanced to the drum and yieldingly held in position by the flanged edge 61 of a cylinder 56. The ring 63 is carried by a series of spring fingers 62 projecting from an inner cylinder 60 which is mounted for synchronized and relatively-axial movements with the cylinder 56. These, movements are effected by rods 58 which are connected at one end to a disc 57 and at the other end to a lever 59 having a roller 115 engaging a groove 120 in the cam 110. When the disc 18 is retracted to move the stitcher ring 9 clear of the drum, it acts as an abutment to effect the displacement of the cylinder 60 to the position shown in Fig. 18, whereupon the folding-device 40 is actuated to operate on the ply-material projecting beyond the bead. The bead-setting device and folder 40 are then withdrawn to permit the ring 9 to fold and stitch down the edge of the ply-material and the bead flipperstrip. Tread stock stitching. A pair of devices operating outwardly from the centre-line of the tread each comprise a resilient annulus 71, Figs. 5 and 28, formed of short helical springs connected by plugs and carried by a series of arms 77 pivoted to a ring 80 which is moved towards and from the drum by means of rackbars 81 connected to the ring 80 and actuated by pinions 83. The ring 80 is slidably mounted on a cylindrical support 84 having a notch 86 in which rollers 87 on the arms 77 are held when the parts are in the rearward position shown in broken lines at the left-hand side of Fig. 27. As the stitcher-rings 71 approach positions over the centre-zone of the tread, the member 84 is arrested and, in the further advance of the ring 80, the rollers 87 leave the notch 86 and ride down a ramp 94 at the forward end of a fixed drum 89. The rings 71 then automatically contract into operative pressing engagement with the tread material. Actuation. The drum A is driven from a motor 3 with manually-controlled start and stop switches. The fabric folding, stitching and bead-applying devices are operated from a motor 104, and the tread-stitching devices from a motor 95, all these devices being actuated in timed sequence by means of the cam 110. The motors 104, 95 are inter-controlled through switches operated by spaced tappets on the cam and one of the racks 81. Specification 614,162 is referred to.