| 摘要 |
A forming drum for a green tire is provided to extend the life time of a bladder by operating the bladder after inflating the bladder, by vertically moving up and down a shoulder support and to maintain uniformity of the tire by increasing the inflation height of the bladder formed in a bead unit. A forming drum for a green tire is composed of a center unit(3) having a center plate(2) installed about a main shaft having spindles simultaneously turned to the left or right side in an axial direction; left and right drums of the same structure symmetrically disposed about the center unit; and a bladder(6) supported to a vacuum ring installed at the left and right drums. The center plate of the center unit comes into contact with a side ring of the vacuum ring through oblique tapered surfaces(8a,8b). A shoulder support(10) interposed between the vacuum ring and a bead lock(9) is moved up and down by a driven tapered surface coming into contact with a drive tapered surface of a first cone piston(11) moving back and forth by pneumatic pressure. Cover rings(13) moving back and forth along the main shaft by pneumatic pressure to cover or open the bladder are installed at the left and right drums.
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