Abstract: A ground anchor comprises a threaded portion, a head portion and a spreading means.

Abstract: A device provided on machine tools for transmitting torque onto tools, comprising at least two diametrically opposite rotary driving grooves openly issuing at the end of the tool shank and rotary drivers engaging in these and at least one locking member being disposed in the tool seat to be radially movable for engagement in a locking groove in the tool shank closed at both ends in the axial direction, wherein the rotary drivers comprise a cross section tapered in the direction of the rotary axis to have a stepped shape and, respectively, at least two rotary driving surfaces mutually offset to have a stepped shape for reducing susceptibility to wear. A tool for insertion in such a device.