LENKVORRICHTUNG FUER EINE BOHRERSPITZE IN EINEM BOHRLOCH

摘要

In a device 10 for steering a drill bit a section of drill pipe (12) adjacent the bit is provided with a rotatably mounted body (14) housing a series of pistons (24a-f) and leaf springs 28 which contact the borehole wall 27 so that the body (14) remains stationary as the chill pipe 12 is rotated. Flushing fluid is caused to move selected pistons (24a-f) radially by a control device 58, 36 which is actuated by signals from a sensor 64 which senses deviations of the drill bit. The control means is powered by an electric generator 50 which is turned by turning the drill string. <IMAGE>