Abstract: A regulating device is for use in a drill string between a drilling machine and a drill bit. The regulating device has a tubular female portion which at least partly encloses a tubular male portion; a helical coupling between the female portion and the male portion to allow a telescoping movement of the regulating device in both directions between a fully extended position and a fully retracted position, the movement of the regulating device occurring when there is a difference in rotational speed between the female portion and the male portion; a first biasing device which is arranged to exert a driving force to drive the regulating device towards its extended position; and a second biasing device.

Abstract: A regulating device is for use in a drill string between a drilling machine and a drill bit. The regulating device has a tubular female portion which at least partly encloses a tubular male portion; a helical coupling between the female portion and the male portion to allow a telescoping movement of the regulating device in both directions between a fully extended position and a fully retracted position, the movement of the regulating device occurring when there is a difference in rotational speed between the female portion and the male portion; a first biasing device which is arranged to exert a driving force to drive the regulating device towards its extended position; and a second biasing device.

Abstract: An ejector pump or jet pump is for use in the drilling of wells in the underground for the production of oil and gas, for example, in which it is the purpose to prevent the total fluid pressure at the bottom of the borehole from reaching a level which constitutes a risk of cracking the rock or sediment being drilled, thus resulting in leakage and circulation failure. For this purpose, the pump is placed between the drill bit and the drill string by means of standard pipe couplings and formed as an elongated cylindrical element with external, longitudinal pump elements with nozzles directed in such a way that low pressure is established externally at the drill bit. The pump is operated by the drilling fluid which is supplied in the normal way from the drill string. The pressure difference across the pump is used to draw a secondary flow of drilling fluid from the established borehole through internal bores in the pump casing to the ordinary nozzles in the drill bit.

Abstract: A method for reducing friction between interconnected outer and inner helical members of a downhole damper where the damper includes an outer damper body and an inner damper body, and where the outer and inner damper bodies are telescopically movable relative each other, the outer and inner damper bodies being biased in the extending direction, and where one of the outer and inner damper bodies are connected to a drill bit workable at a borehole face, and where the other of the outer and inner damper bodies is connected to a torque and force transmitting member, and where the outer and inner helical parts are arranged so as to retract the bit from the face when torque applied by the torque and force transmitting member exceeds a preset value, wherein the method includes letting a relative movement between the inner and outer body force lubricant to flow between the helical members.

Abstract: A torque converter for use in drilling with a rotating drill bit, the purpose of the torque converter being to absorb impacts and bring about an axial movement of the drill bit when the torque exceeds a predetermined value. For this purpose the torque converter is composed of two cylindrical string parts connected through the bearing elements. The string parts are connected to each other through helical elements in such a way that relative rotation of the two cylindrical string parts brings about axial movement, which unloads the drill bit.