Abstract: A locking device and a locking method are provided for a tool holder of a rotary drilling rig. The locking device includes a sleeve, a locking pin, a movement system, and a control system. The sleeve and the locking pin are configured such that the sleeve engages around the locking pin with a form fit, such that the locking pin can be rotated in the sleeve about the longitudinal axis of the locking pin. As a result, the locking pin can be displaced laterally parallel to the longitudinal axis. The movement system has at least one electric motor and at least one shaft, wherein the shaft effects relative rotation of the sleeve and the locking pin by the force of the electric motor.

Abstract: A locking device and a locking method are provided for a tool holder of a rotary drilling rig. The locking device includes a sleeve, a locking pin, a movement system, and a control system. The sleeve and the locking pin are configured such that the sleeve engages around the locking pin with a form fit, such that the locking pin can be rotated in the sleeve about the longitudinal axis of the locking pin. As a result, the locking pin can be displaced laterally parallel to the longitudinal axis. The movement system has at least one electric motor and at least one shaft, wherein the shaft effects relative rotation of the sleeve and the locking pin by the force of the electric motor.

Abstract: A process for exactly holding the vertical excavation direction of a diaphragm wall using a hydraulic diaphragm wall grab cooperating with an excavator and having an outer guide body and an inner body for receiving the grab appliance is improved and rendered considerably more efficient by the fact that the vertical position of the inner body and/or the guide body is continuously controlled by means of an inclination detector whose-signals are transferred to a controller which, in case the bodies of the grab deviate from the predetermined vertical position, compensates said deviation by swivelling the inner body relative to the guide body in opposite direction to the deviation.