| 摘要 |
<p>A positioning tool of the kind in which a support member, a revolving tool table, for instance, is rotatable with respect to a base to support an equipment which is to be rotated about an axis of rotation, the support member comprising a worm wheel (5), which, to rotate the support member, meshes with drive worms. To make possible not only a revolving motion of the support member but a motion thereof in a direction perpendicular to the rotational axis thereof, the worm wheel (5) thereof is, in accordance with the invention, meshing with two mutually parallel and axially non-displacable drive shafts (9 and 10, resp.), provided with screw threads (8) corresponding to the teeth (7) of the worm wheel arranged on each one side of the worm wheel and acting as drive worms, the screw threads of said shafts having a length at least corresponding to the length of an intended motion of the support member in a direction parallel to the direction of the two drive shafts.</p> |
