Patent ID: 6808029
Filing Date: 2004-10-26
Classification: E21B

Abstract:
A drill rig assembly comprising a drill mast, a storage device for storing a number of drill pipes near said drill mast, a rotary head having a rotating part arranged to be coupled to one extremity of a drill pipe and a fixed part mounted onto a rotary head trolley assembly which is movable up and down along said drill mast, and means for moving the trolley assembly and the rotary head along the drill mast to feed a string of drill pipes coupled to the rotary head in and optionally back out of the ground, said rotary head being provided with a clamping assembly provided to hold a drill pipe with an extremity thereof which is arranged to be coupled to the rotating part of the rotary head, and the drill rig assembly further comprising means for moving the rotary head with respect to said rotary head trolley assembly, which means are arranged, together with the means for moving the rotary head trolley assembly along the drill mast, to enable the rotary head to clamp with said clamping assembly a drill pipe in the storage device and to position the drill pipe on top of the drill string, substantially in axial alignment thereto, said clamping assembly comprising first and second mutually co-operating clamping means to clamp the drill pipe between them, the first clamping means comprising a tubular portion arranged to partially enclose the extremity of the drill pipe to be clamped therein and having a longitudinal slit enabling said extremity of the drill pipe to be inserted laterally into this tubular portion.