| 摘要 |
<p>A tire building drum is described as having a unique mechanism for controlling the radial movement of the bead lock segments which are designed to hold the tire bead rings firmly, in position, during the turn-up operation. The mechanism includes an annular support member which is disposed concentrically around the longitudinal center axis of the drum adjacent opposing ends of the drum, and which has a number of raceways that are radially oriented in relation to said center axis. The raceways are equally, angularly spaced about said axis and are designed to slidably receive a bead lock segment on which a cam roller is freely mounted for rotation. The mechanism also includes an annular scroll member which is disposed concentrically around said axis in side-by-side parallel relation with each of the support members. Each of the scroll members is rotatable about said axis and has a grooved trackway which spirals around said axis at least one and one-half times and which is designed to receive the cam rollers which project from the adjacent bead lock segments. It can be appreciated that the segments will be forced to move in radial directions in response to rotation of the scroll members. The mechanism further includes any suitable device, such as a pair of pistons reciprocative, in unison, in separate annular bores concentric about said axis, for rotating the scroll members, in unison, to simultaneously move the bead lock segments in equal radial distances to and from the center axis of the drum.</p> |
