| 摘要 |
A fluidically operable hollow rotary clamping apparatus such as for use in lathes, has a housing wall and a piston portion located therein with the surface thereof together with the seal packing secured to the housing wall form a double-acting cylinder. This double-acting cylinder is impacted via two pressure medium inlets. A flange secured to the housing wall and the piston portion which is displaceable in only longitudinal direction, each support a group of ball bearings in which a rotary part is mounted. This rotary part contains symmetrically arranged gearwheels of a racked-bar differential drive, whereby the outer pair of gearwheels acts on a pair of racked bars on a guide tube and the inner gearwheel having a larger or smaller diameter and a greater or lesser number of teeth acts through slots in the guide tube on a racked bar on the actuation tube. The actuation tube is in operational engagement with a collet or the like. Such a clamping or tensioning apparatus has a better degree of efficiency than the known device, is heated in use to a lesser degree and has a small rate of leakage and may be operated by the standard machine hydraulics or pneumatics due to considerable power transmission. |
