Abstract: A device for guiding a drilling tool in rotation, the device including a tubular longitudinal element, a transmission shaft passing longitudinally through the tubular element, the shaft being rotatably mounted in the tubular element for rotating the drilling tool, the guiding device including bearing blocks mounted between the tubular element and the shaft, each bearing block being attached to at least one attachment region on the shaft, characterized in that the bearing block including at least one tapered bore ball-joint roller bearing, wherein at least in the attachment region, the shaft has a taper less than or equal to 1:12 and/or bend radii greater than 1/12th of the outer diameter of the shaft.

Abstract: An annular device generates essentially radial displacements of a shaft disposed within the device includes a frame, a swiveling ring and in internal ring with which the shaft is associated. Actuators and guide rods within the housing cause the swiveling ring to rotate relative to the frame and the internal ring to be displaced radially such that a shaft associated with the internal ring is radially displaced. The device is useful for drilling trajectory control devices.

Abstract: The invention relates to a device for generating essentially radial displacements and/or stresses of at least one mechanical part with respect to its X-X axis common with that of at least one other mechanical part functionally connected to the first one, said device comprising: (I) a frame, a swivelling ring (11) and an internal ring producing two nested ball joint connections (a) and (b) with respective centres A and B, eccentric by a distance or value ? along said X-X axis common to the two rings in a position said to be neutral, (II) one or more actuators in a barrel arrangement about the X-X axis for driving the mechanism, each actuator acting on the swivelling ring (11) via a guided push rod (3), and (III) a guide ring (4) for guiding the push rods (3) via a bidirectional planar link (e), while the swivelling rings (11, 13) are steerable by means of push rods (3) displaced by the actuators (2) and guided by the guide ring (4), and while said swivelling rings are rotatable in their respective housings