Patent ID: 6401841
Filing Date: 2002-06-11
Classification: E21B

Abstract:
A rotary table for a drill string, including a stationary frame having a rotating part arranged therein, and hydraulic slips (wedge-shaped holding collars) and a hydraulic clamp on the rotating part, and hydraulic power transmission between the stationary frame and the rotating part, comprising hydraulic transmission for each hydraulic slip and clamp including a hydraulic motor on the stationary frame, a hydraulic pump having an input shaft with a gearwheel on the rotating part, and a ring provided with internal and external toothing which is supported on the rotating part so as to be coaxially rotatable, wherein the internal toothing on the ring is in driving engagement with the gearwheel on an input shaft in the hydraulic pump and the external toothing on the ring is arranged for engageable and disengageable driving interaction with the hydraulic motor via the gearwheel on the output shaft of the hydraulic motor.