Patent ID: 6955232
Filing Date: 2005-10-18
Classification: E21B

Abstract:
1. Equipment for drilling vertical boreholes in hard ground, the equipment comprising: casing put successively into place in the borehole; a drilling machine comprising a rotary cutting head having a diameter, a structural frame and a motor unit for rotating said cutting head with respect to said structural frame, said motor unit being mounted on said structural frame; torque and thrust transmission means, distinct from and mounted above said drilling machine, having a lower end secured to said structural frame of the drilling machine and an upper end, said transmission means being cylindrical in shape and having a diameter substantially equal to the diameter of the cutting head; securing means entirely mounted on said upper end of the transmission means, said securing means including movable securing members each securing member being suitable to take up second position wherein said member cooperates with a portion of said casing to secure said transmission means to said casing and a first position wherein said secunng member does not cooperate with said casing; and control means to control the position of said securing members.