| 摘要 |
A driving roller with an outer working periphery having a changeable diameter has a first disk and a second disk arranged coaxially with one another and returnable relative to one another in any operational condition, the first disk being provided with a plurality of radial guides, the second disk being provided with at least one spiral-shaped guide, a plurality of supporting bodies which for abutment of segments provided for the drive belts have a first element cooperating with the radial drives and a second element cooperating with the at least one spiral shaped guide and are supported with these elements so that by a relative turning of the disks an increase or a reduction of the diameter of the working periphery is provided, the radial guides being formed by guiding slots extending through the first disk, the first element being composed of guiding members which are slidingly guided in the guiding slots, the guiding members at both sides of the first disk being provided with guiding webs which laterally extend over the guiding slots |
