Abstract: A rotor system for a downhole motor comprises a set of permanent magnets, a set of conductors and a pair of end conductor rings connecting the set of conductors. The set of permanent magnets and the set of conductors being substantially coaxial and having the substantially the same linear extent. The set of permanent magnets can be located radially inwards from the set of conductors, and may be provided by discrete conductive bars.

Abstract: A rotor system for a downhole motor includes at least one permanent magnet rotor section, and at least one squirrel cage rotor section. The permanent magnet rotor section and the squirrel cage rotor section are joined in series by a connection. In one example the connection includes a male self lock taper on one rotor, and a corresponding female self lock taper on the other rotor.

Abstract: A hydraulic strut assembly, for use in a semi-levered landing gear in an aircraft, comprising an actuator and a manifold associated with the actuator. The actuator comprises a housing, a first piston, a second piston, and a third piston. The first piston is positioned between outer and inner cylindrical structures of the housing. The outer and inner cylindrical structures and first piston form an outer chamber that receives a first fluid. The inner cylindrical structure, the first piston, and the second piston, which is nested within the first piston, form an inner chamber, which holds a second fluid comprising a gas. A volume of the inner chamber changes when at least one of the first and second pistons moves. The third piston is positioned between the outer cylindrical structure and the first piston. The first, second, and third pistons move in a direction parallel to an axis through the housing.

Abstract: A power tool, including a housing and a handle having two ends. The first end of the handle being moveably mounted to the housing via a first mounting assembly and the second end being moveably mounted to the housing via a second mounting assembly. One part of the first mounting assembly including a sleeve and the other part including a rod mounted in an axially slideable manner in the sleeve. A biasing mechanism connected between the two parts. One part of the second mounting assembly including a support and the other part including a pin located in the support which is capable of being rotated in the support to enable the second end of the handle to rotate relative to the housing and to move linearly in the support to enable the second end of the handle to move linearly relative to the housing.

Abstract: A technique for making a handle vibration-proof while avoiding size increase is provided in an impact tool. The impact tool has a striking mechanism part for driving a tool bit in its axial direction, a motor for driving the striking mechanism part, a tool body housing the motor and striking mechanism part, an outer shell housing covering part of the tool body, a handle that is integrally formed with the outer shell housing and extends transversely to the axial direction, a first handle end portion formed on one extending end of the handle, a second handle end portion formed on the other extending end of the handle, a first elastic element that connects the first handle end portion and tool body for relative movement in the axial direction, and a second elastic element that connects the second handle end portion and tool body for relative movement in the axial direction.

Abstract: The invention relates to a tool that includes a tool holder, which has on its first end a tool holder recess that is adapted to the contours of a rotating spindle driver and a tool recess on a second end that lies opposite the first end. The tool holder also includes a tool head that can be inserted into the tool recess. For the optimal machining of a workpiece, attempts were previously made to provide an oscillating unit in the spindle of the machine, to initiate oscillations in the tool head. The disadvantage of said known constructions is that all available tools have to be synchronized with the oscillation unit. The invention overcomes said disadvantage by equipping the tool holder with an oscillating motor.

Abstract: A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

Abstract: Provided is a downhole percussion drill, which is installed at an end portion of a drillstring and performs drilling by giving impact blows to a drill bit at the bottomhole, which includes a hydraulic hammering mechanism 7 which uses oil having high lubricating ability as a driving medium, a hydraulic pump 8 which pressurizes the oil, and a downhole motor 9 which drives the hydraulic pump 8.

Abstract: Provided is a downhole percussion drill, which is installed at an end portion of a drillstring and performs drilling by giving impact blows to a drill bit at the bottomhole, which includes a hydraulic hammering mechanism 7 which uses oil having high lubricating ability as a driving medium, a hydraulic pump 8 which pressurizes the oil, and a downhole motor 9 which drives the hydraulic pump 8.

Abstract: A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston-causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system.

Abstract: A hydraulic drilling outfit has a hydraulically driven hammer drill which is fastened pivotally to a hydraulic thrust unit. A control for the hydraulics utilizes the flushing water for the drill bit as the power-source for all of the motions executed by the drilling outfit. One hydraulic supply line to the control of the thrust unit and one line from the control to the hammer drill are sufficient for operating the system in an open circuit. A rotary slide valve simultaneously controls the thrust and withdrawal motions as well as the operational states of drilling and not drilling. The desired value adjustment for the speed of thrust is arranged on the rotary slide valve.

Abstract: A downhole hammer is provided comprising a casing having a top sub at one end and a drill bit and support at the other end. A central tube is extended therethrough to define an annular space between the casing and the tube. A reciprocating piston is accommodated within the annular space and is operated by injecting a pressurized fluid from the surface into the annular space via a plurality of ports in the casing. The pressurized fluid is exhausted into the central tube and toward the surface via a plurality of passageways therethrough without contacting the borehole.

Abstract: A power swivel particularly adapted for downhole cementing operations. The power swivel includes a housing having a fluid passageway therethrough and a stem assembly mounted for rotational movement with respect to the housing and having a fluid passageway communicating with the housing passageway. A hollow bore motor mounted with the housing receives the stem assembly through a central bore of the motor and rotates the stem assembly with respect to the housing.

Abstract: A machine for machining bars, rods, tubes and similar articles, e.g. by cutting a thread thereinto is provided with a cutting head journalled by means of a spindle or the like on a housing, and is also provided with a motor, e.g. an electric motor, which is axially aligned with the cutting head. Between the motor and the cutting head there is arranged a transmission having a driving or input gear which is drivingly connected to the motor shaft and having an output gear of the transmission drivingly connected to the cutting head. The transmission is a planetary gear transmission which is arranged in axial alignment with the motor and the cutting head.