DEVICE FOR ANCHORING IN A CASING IN A BOREHOLE IN THE GROUND

摘要

A device for anchoring in a casing in a borehole in the ground. The device comprises a shaft oriented in an axial direction, the shaft having a torque transfer section. The torque transfer section has axially oriented outer cam surfaces extending radially outwardly in a rotational sense. The shaft further has a plurality of clamping bodies circumferentially distributed around the torque transfer section with a limited movability relative to the torque transfer section in rotational sense and in radial directions. The clamping bodies each have an inner, axially oriented clamping body surface facing one of the cam surfaces of the torque transfer section and an outer surface defining a segment of a cylinder coaxial with said shaft.

主权项

1. A casing system for lining a borehole in the ground comprising a casing section and a device for anchoring in a casing in a borehole in the ground, the casing having an inner wall surface, the device comprising:
a shaft oriented in an axial direction, the shaft having a torque transfer section; the torque transfer section having axially oriented outer cam surfaces extending radially outwardly in a rotational sense, the shaft further comprising a drilling assembly including a drill bit and a reamer projecting from an end of the casing and wherein the lower end of the casing is located closely adjacent the reamer while the anchoring device is anchored to the casing; and a plurality of clamping bodies circumferentially distributed around the torque transfer section with a limited movability relative to the torque transfer section in rotational sense and in radial directions, the clamping bodies each having an inner, axially oriented clamping body surface facing one of the cam surfaces of the torque transfer section and an outer surface defining a segment of a cylinder coaxial with said shaft, wherein the clamping bodies are arranged for clamping against said inner wall surface and being released therefrom.