Equipment for drilling vertical boreholes

2/ Equipment according to claim 1, wherein said securing means comprise a plurality of catch elements formed in the inside face of the casing, and moving locking members mounted at the second end of the torque and thrust transmission means, said locking members being suitable for taking up a retracted first position at rest and an active second position in which they co-operate in rotation and in translation with the catch elements.

3/ Equipment according to claim 1, wherein said securing means comprise a plurality of tube elements securable to the second end of the torque and thrust transmission means and securable to one another and to fixing means for fixing the top tube element in translation and in rotation to the top end of the casing.

4/ Equipment according to claim 1, wherein said securing means comprise an annular body secured to the second end of the thrust and torque transmission means, and expandable means mounted on the outside face of said body and suitable for occupying a first position at rest and an active second position in which the expandable means apply pressure to the inside face of the casing.

5/ Equipment according to claim 4, wherein said expandable means comprise a plurality of inflatable envelopes secured to the outside face of said cylindrical body, and means for injecting a fluid under pressure into said inflatable envelopes and for removing said fluid from said envelopes.

6/ Equipment according to claim 4, wherein said expandable means comprise a plurality of shoes mounted to move relative to said body, and displacement means for applying said shoes with pressure against the inside face of the casing.

7/ Equipment according to claim 2, wherein the catch elements comprise a series of through orifices formed in said casing, the orifices in a given series being disposed in a common plane orthogonal to the longitudinal axis of the casing, the series of orifices being offset in the axial direction of the casing, and wherein the moving locking members comprise a plurality of locking fingers that are movable radially between a retracted first position at rest and an active second position in which said fingers penetrate into the orifices of a series of orifices.

8/ Equipment according to claim 7, wherein said orifices and said locking fingers are frustoconical.

9/ Equipment according to claim 1, wherein said catch elements comprise a series of catch pieces projecting from the inside face of the casing, the catch pieces in a given series being disposed in a common plane perpendicular to the longitudinal axis of the casing, said series being offset in the axial direction of the casing, and wherein the moving locking members comprise a plurality of latches movable radially between a retracted first position at rest and an active second position in which said latches co-operate with said catch pieces both in rotation and in translation.

10/ Equipment according to claim 9, wherein each series of catch elements comprises an annular part projecting from the inside face of the casing and a plurality of longitudinal parts that are angularly spaced apart and that project from the inside wall of the casing.

11/ Equipment according to claim 1, wherein said drilling machine has a front portion carrying the rotary cutting head and a structural frame, a rear portion comprising a structural frame, and actuator means for moving said front portion relative to said rear portion, the first end of said torque and thrust transmission means being secured to the structural frame of said rear portion.

12/ Equipment according to claim 1, wherein said thrust and torque transmission means comprise a cylindrical part of longitudinal axis that coincides with the axis of the casing.

13/ Equipment according to claim 1, wherein said casing is constituted by a plurality of casing elements that are connected to one another.