Abstract: A mechanical device that is used to prevent injury to workers that are handling pigs during launch insertion into a pipe. The mechanical device is attached to a large piece of construction equipment so that workers do not have to handle the pig.

Abstract: A rig adapted for rock bolting comprising a feeding magazine is provided. The feeding magazine comprises a holding structure for bolts and is arranged in conjunction with a rock reinforcement unit. The rig further comprises a feeding device that is arranged to provide the rock reinforcement unit with bolts from the feeding magazine. The rig further comprises a loading magazine comprising a holding structure for bolts, as well as a, relative to the feeding magazine and the loading magazine, moveable picking device arranged to move bolts that are located in the loading magazine such that they are accessible to the feeding device.

Abstract: A pipeline robot capable of steering actively comprises at least two driving knuckles and at least one steering knuckle. Every two adjacent driving knuckles are connected by the steering knuckle. A front end cover is fixed on the front end surface of the driving knuckle at the most front end. A sensor is mounted in the center of the front end cover. A rear end cover is fixed on the rear end surface of the driving knuckle at the rearmost end. A universal spherical hinge is arranged in the center of the rear end cover. Each driving knuckle comprises a main frame, driving mechanisms and telescopic mechanisms; the telescopic mechanisms are mounted in the main frame, and capable of causing contraction of the driving mechanisms into the main frame. The steering knuckle can drive the front driving knuckle connected thereto to steer.

Abstract: A mobile support structure (MSS) includes a frame structure for receiving modular silos, a base moveable between transportation and support configurations, and connectors coupling with the silos. A mobile erecting assembly includes a chassis, a lift structure rotatable between transportation and mounting orientations while engaged with a silo, an engagement structure movable between first and second positions while engaged with the silo, and an actuator to move the engagement structure and silo between the first and second positions. The silo is connected to the mobile erector assembly in the transportation orientation, and the mobile erector assembly is then aligned relative to the MSS, such as by engaging an alignment member of the mobile erector assembly with a chassis alignment post of the MSS. The mobile erector assembly is then operated to move the silo to the mounting orientation, and the silo is then coupled to the MSS.

Abstract: A rock drilling system comprising a rock drill adapted to hold a drill steel to which a drill bit is connected, a drill feed rail for slidably supporting a drill feed that displaces the rock drill along the drill feed rail, a stinger-supported centralizer assembly for centralizing the drill steel, wherein the stinger-supported centralizer assembly has a centralizer base made of an elastomeric material, and a travelling cradle centralizer assembly slidable over the drill feed rail for centralizing the drill steel, wherein the travelling cradle centralizer assembly has a cradle made of an elastomeric material.

Abstract: The Overhead Drill and Anchor Press is a single mobile mechanism designed for installation of anchors into a construction surface which is overhead and out of reach of the installer. The overhead drill and anchor press is comprised of these major components: a compartmentalized cart on casters, a telescopic mast, a turret assembly, a controller, an air reservoir tank, a battery, a battery charger, and a DC power supply. The overhead drill and anchor press can execute the anchor installation sequence automatically or manually with a controller that may be hand held, or placed on the hand rail of the cart. The controller is equipped with a digital display of the turret mounted camera for monitoring the process from the ground. The entire assembly of the embodiment is designed to be manually pushed between target locations and sized to fit through standard framed door openings on a construction project.

Abstract: A drive device having a main drive device, a gearing, a switchable clutch, at least one hydraulic pump, and a gearing output shaft is started with low wear by providing an auxiliary drive to drive the gearing output shaft independently of the main drive device. A work machine device includes the drive device and a work machine which can be started accordingly in a low-wear manner and which enables longer-term operation in the reverse direction of rotation. Corresponding methods which are also provided in connection with the drive device and the work machine device, enable low-wear starting and the elimination of undesired operating states.

Abstract: A tubing device is operatively connectable to an excavation machine. The tubing device comprises a base frame, at least one guiding tower operatively connected to the base frame, and a tube operating unit, operatively connected to the guiding tower. The tube operating unit is slidable along the guiding tower and is provided with engaging means capable of both selectively holding a tube segment, and of transmitting a rotary motion and an axial sliding movement to such a tube segment so as to allow the progressive driving in the ground and subsequent extraction from the ground.

Abstract: The drilling rig includes a first substructure and a second substructure. The second substructure is positioned generally parallel to and spaced apart from the first substructure and generally the same height as the first substructure. The drilling rig further includes a drill floor coupled to the first and second substructures, where the drill floor positioned substantially at the top of the first and second substructures.

Abstract: A remote controlled drilling rig that is fully functional includes a drilling rig, an electrical assembly, and a remote. The drilling rig includes a truck for towing a semi-trailer on which is positioned a derrick and a drilling assembly. The electrical assembly is positioned within the drilling rig and includes a battery for powering components of the drilling rig, in addition to a receiver and circuit board for receiving and processing command signals respectively. The receiver is communicably coupled to a transmitter housed within a casing of the remote. A plurality of controls is used to send input commands to the transmitter, which are in turn transmitted to the receiver in order to control functions of the drilling rig, such as raising and lowering the derrick. A draw-works assembly allows for raising and lowering a traveling block within the derrick by winding and unwinding a drilling cable connected between.

Abstract: Jointed concrete pavement is formed of concrete cured around a dowel. The dowel includes a welded seam carbon steel hollow tube and a pair of end caps. The end caps are attached to opposite axial ends of the hollow tube. The pavement comprises a fracture groove over the dowel.

Abstract: In control methods for a multi-function controller, which includes a sensor having a ring operation region, the position of an object on the sensor is detected for generating a position information, and the force applied to the sensor by the object is detected for generating a force information. When the sensor detects multiple successive position information, which indicate that the object is circling along the ring operation region, a rotation information may be generated additionally. The position information, the force information and the rotation information are used to perform operation in various functional modes.

Abstract: A machine tool adapted to perform operations, for example, machining, on a surface of a part of large size is provided. The machine tool comprises a longitudinal rail and a transverse arm, orthogonal to the longitudinal rail, slidingly fastened at a first end to the longitudinal rail. A second end of the transverse arm is provided with a unit comprising a holding device enabling the unit to be held in position on the part during an operation. The transverse arm bearing a tool is thus precisely positioned on the part on which the operations are carried out.

Abstract: Forcing equipment meant for forcing piles, steel profiles and other elongated objects into the ground which forcing equipment comprises a body (1) which can be attached to a working machine, a vibration device (6) attached to the body (1) with the help of damper cushions (9) and moveable grip jaws (10) adjusted to the mentioned vibration device (6) in order to grip the object to be forced at least with a side grip. The body (1) comprises an upper part (2) including an attachment arrangement (4), (5) for attaching it to the working machine and side parts directed from the upper part (2) downwards between which side parts the vibration device (6) and grip jaws (10); (17, 18) can be attached through cassette (7) comprising damping rubbers (9) in which case the attachments comprise pin/hole attachments (11, 23, 14); (20, 8) or (21, 8) which can be opened by detaching the mentioned pins (11, 20, 21).

Abstract: A mobile drill rig includes a frame structure and a plurality of hinged outriggers that are adapted to be retractable to a substantially vertical position during a drilling operation and extendable to a substantially horizontal position during movement of the mobile drill rig. The frame structure is adapted to transfer a weight of the mobile drill rig through the plurality of hinged outriggers to a plurality of wheeled frame dollies during the rig movement.

Abstract: An improved base structure for a derrick mast of a pivotal portable drilling rig structure provides at least two A-frame support members affixed to a rig side of the derrick mast, the drilling rig structure being elevated to a point slightly forward from vertical position towards a well side, with the A-frame support members held in a drilling position by respective support member stanchions which apply static force below the A-frame support members during use of the drilling rig structure applying enhanced drilling forces and stability applied during the drilling process. A rig side secondary locking support structure secured to an elevating drilling rig platform provides additional stability to the drilling rig structure when the drilling rig is in an operational position subsequent to the positioning of the A-frame support members and the support member struts.

Abstract: Hammering device meant for hammering poles, steel profiles and other elongated objects into the ground which hammering device comprises a body (1) which can be attached to a power tool, a vibrator device (6) which is attached to the body (1) with the help of damping cushions (9) and movable gripping jaws (10) which are adjusted to the mentioned vibrator device (6) in order to grip the object to be hammered at least with a side grip wherein the gripping elements (23) of the gripping jaws (10) can be brought closer and farther away with the help of a regulating unit, such as a hydraulic cylinder (16).

Abstract: Disclosed embodiments are directed toward driver implements and methods for driving rigid members into a support surface. In some embodiments, the disclosed driver implement is combined with a power machine that provides operation signals to the driver implement. Other embodiments disclose a rigid member that is configured to be driven into a support surface by various embodiments of the driver implement.

Abstract: A telescoping leader for a construction vehicle for accommodating a vibrator, pile driver, earth drilling gear mechanism, or the like, has an outer leader that is disposed so that it can be longitudinally displaced relative to an inner leader. The inner leader and outer leader have closed material cross-sections, and the outer leader surrounds the inner leader. At the end of the outer leader that can be displaced on the inner leader, and at the end of the inner leader that is guided in the outer leader, a guide is firmly disposed, on which the outer leader can be displaced.

Abstract: A pile driver assembly consisting of a plurality of pile driver units interconnected together to a rigid base frame that uses the push and pull method to drive a group of raked piles. The pile driver units progressively push one pile at a time for a short distance into the ground while being pull down by the rest of the stationary driven piles in a repeated cyclical driving sequence until the required pile driving force is reached for every pile in the group. The pile driver assembly consists a plurality of interconnected pile driver units, a pile driver base adaptor, a pile clamping system and strong base frame to drive the piles in a two dimensional array of variously raked pile group from 1V:1H to true vertical in the z-axis and rotated to any angle in the x-y plane at a minimum pile's spacing of three times the pile's diameter.

Abstract: A telescoping leader system for a construction machine that includes a set of leads having a series of internal nesting segments and an extending means connecting one segment to another segment to allow for the extension of the segments one after the other to an extended position and the retraction of the segments to an internal nesting position. The telescoping leader system further includes a surface engaging member mounted within the set of leads and a pivotable mounting assembly mounted to the set of leads and adapted to adjust the position of the set of leads. A quick connecting means adapted to engage the pivotable mounting assembly is included to allow for the quick engagement and disengagement of the construction machined from the set of leads.

Abstract: Equipment serves to form consolidated soil columns having a non-circular cross-section, and includes a mast (2, 8), a rotary (3) which is rotatable and translatable along an axis parallel to the mast, a series of hollow rods (4) temporarily unlockable from the rotary (3), and a device to vary the rotational rate of the rotary in one or more prefixed angular ranges. A rotor (21) is directly secured to one of the rods of the string and operatively coupled to a device (20) generating control signals to vary the rotational speed of the rotary in response to the rotor angular position. A through clamp (10) is mounted to the rotatable mandrel of the rotary and is provided with locking members which can be activated to clamp a rod and make it integral to the rotary, and which can be deactivated to release the rod so as to allow the rotary to move relative to the rod.

Abstract: A feed unit (105) to be used with a mining or construction machine (100), the feed unit (105) having a feeder holder (106) and a feed beam (111) able to move relative to the feeder holder (106), the feed unit (105) also having a supporting unit for a drilling machine (121), the supporting unit being arranged to support the drilling machine (121) moveably in relation to the feed beam (111), and the feed unit (105) having a driving device to move the feed beam (111) relative to the feeder holder (106) in operation. The supporting unit is attached to the feeder holder (106) such that, when the feed beam (111) moves relative to the feeder holder (106) by the driving device, the supporting unit is automatically moved at the same time along the feed beam (111). A rock drilling assembly and a rock drilling rig include the feed unit.

Abstract: An apparatus for driving piles or drilling holes includes a self propelled vehicle with a mounting platform supported by the vehicle. A lifting and positioning arm is provided having a mounting end and a remote end. The mounting end is mounted to the platform. The arm rotates about a vertical axis relative to the platform wherein the remote end of the arm is positioned in a selected radial orientation relative to the platform. The arm pivots about a substantially horizontal axis relative to the platform wherein the arm is moved up and down to position the remote end of the arm at a selected height above or below the platform. The arm extends and retracts wherein the remote end of the arm is positioned a selected distance from the platform. A pile driver or drill assembly is pivotally mounted to the remote end of the arm.

Abstract: A handling system (1?) is for drilling equipment (200) of the ground, in which the drilling equipment (200) slides along a support tower (101, 501) fixed or movable with respect to the ground. The handling system (1?) includes at least one linear actuator (3, 3a, 3b) for handling the digging equipment. The linear actuator (3, 3a, 3b) being temporarily movable and releasable with respect to the tower (101, 501).

Abstract: The present invention provides a pile driver capable of improving operability while preventing breakage and the like of a wire rope by relating a press-in winch and an elevation winch to each other. Solenoid valves are arranged respectively to hydraulic circuits of both of a press-in winch and an elevation winch and an electric circuit is provided to operate the solenoid valves in a related manner so that one winch is to be capable of rotating at semi-engaging when the other winch is set to be in a winding state with automatic brake operated.

Abstract: A feeder holding device used with a rock drilling and/or rock bolting rig, in which the rock drilling and/or rock bolting rig has at least one boom with a first end and a second end, the first end is attached to a carrier, and the second end supports a feed beam by the feeder holding device, and in which the feed beam can be adjusted by the feeder holding device in a first drilling position in a first drilling direction and in a second position. The feeder holding device provides linear movement of the feed beam, in a direction different from the drilling direction, from the first drilling position to the second position, such that the feed beam in the second position is pointed in a direction parallel to the first drilling direction. A rock drilling and/or rock bolting rig is also provided.

Abstract: A traveling top drive sheave system includes in one embodiment a rig carrier, a mast assembly pivotally attached to the rig carrier comprising guide rails and a crown block, a top drive fixture, and a traveling sheave block. The mast assembly is moveable to a generally perpendicular position with respect to the rig carrier, providing the top drive access to a wellhead. The top drive is mounted within the mast assembly and is supported along guide rails to be vertically moveable along a same axis as the wellhead. In one embodiment, the traveling sheave block has an axis offset from the crown block to enhance the reeving of a drilling line between both blocks. In another embodiment, the system contains guide rails and rollers whereby at least one of the rollers or guide rails has a groove and the other is sized to mate with said groove for facilitating vertical movement along said mast assembly.

Abstract: An articulated pre-skimmer mount for a pre-skimmer associated with a drill bit feed unit comprises a feed mounting arm mounted to the drill bit feed unit. A first end is configured for attachment to the drill feed unit and a second end includes a cylindrical mounting shaft and an axial positioning plate. An intermediate arm has a first end comprising a cylindrical sleeve mounted thereto. The cylindrical sleeve has an inner cylindrical opening configured for sliding engagement with the cylindrical mounting shaft and a mating plate configured for locking, face-to-face engagement with the axial positioning plate. A second end comprises a pre-skimmer mounting assembly configured for attachment to the pre-skimmer, wherein an axial positioning plate and a mating plate are operable to disengage, for rotation of the intermediate arm about an axis of the feed mounting arm for alignment of the pre-skimmer.

Abstract: The invention relates to a ground working device comprising a carrier implement, a mast that forms a mast sequence and has a lower mast part, which is linked to the carrier implement, an upper mast part and at least one mast extension piece, whereby for the purpose of increasing the mast length the mast extension piece is removably inserted into the mast sequence between lower mast part and upper mast part and removed from the mast sequence, and, with the mast extension piece removed, the upper mast part can be fixed directly on the lower mast part, a work sledge which is guided in a displaceable manner along the mast, and at least one feed rope for displacing the work sledge, which runs at least in some areas longitudinally of the mast.

Abstract: A gauge wheel assembly for a hand held portable power tool has first and second gauge wheels arranged on opposite lateral sides of a working attachment of the tool to contact the ground and gauge the height of the working attachment relative to the ground. The gauge wheel assembly includes a clamp assembly that clamps to an outer surface of a tubular boom of the tool. First and second arms extend outwardly from opposite lateral sides of the clamp assembly and have distal portions that support the gauge wheels adjacent to the lateral sides of the working attachment. A plurality of mounting locations are provided in the distal portions of the first and second arms for adjustably mounting the gauge wheels to the arms. The working attachment can be a rotary sweeper that extends in a cantilever fashion from a center gearbox attached to the tubular boom.

Abstract: A boom arrangement (202) and a drilling rig having the boom arrangement for use in a mining or construction machine (200) the boom arrangement having a first boom section (203) with a first and a second end, in which the first end is designed to be fastened to a carrier (201), and the second end is designed to carry a drilling machine (210), the boom arrangement (202) also having a first rotational linking element (205) with a first axis of rotation (B1) and a second rotational linking element (206) with a second axis of rotation (B2). The first rotational linking element (205) is arranged at the first end of said first boom section (203) and the second rotational linking element (206) is arranged at said second end of the first boom section (203) such that the axes of rotation (B1, B2) are fixed in relation to each other, and the axes of rotation (B1, B2) form angles with vertical direction of the carrier, the angles being in the interval of 0 to 45°.

Abstract: A guide device for hand-held power tools has a guide part which is configured to be placed onto an upper side of a workpiece to be machined. A roller arrangement is held on the guide part and is configured to roll on the workpiece upper side. The roller arrangement has at least one roller which is mounted rotationally on the guide part.

Abstract: An apparatus and method for deep earth grounding includes positioning a power driver at a site, the power driver comprising a frame and an impact hammer operatively connected to the frame, adjusting placement of the impact hammer, raising the impact hammer, driving 10 foot sectioned grounding rods down into the ground at the site using the hammer, testing resistance, and determining if more additional grounding rods are necessary based on the resistance. A power driver device includes an open frame, guide rails operatively connected to the frame, an impact hammer operatively connected to the guide rails and moveable along the guide rails, and a hand crank assembly operatively connected to the frame and configured for raising the guide rails and the impact hammer up and down along the frame.

Abstract: A track guiding system includes a track comprising a linear beam and a linear plate operatively coupled to the linear beam. The linear plate has opposing first and second surfaces separated by a first distance and opposing first and second edges separated by a second distance. A first compound edge roller and a second compound edge roller are disposed adjacent to the first and second edges of the linear plate, respectively, for travel along the first and second edges of the linear plate. Each of the first and second compound edge rollers include a first roller element adjacent to the first surface of the linear plate and a second roller element adjacent to the second surface of the linear plate. A carriage is coupled to the first and second compound edge rollers.

Abstract: A boom arrangement (7) for a rock drill rig (5) including a feed beam unit (8) for displaceable reception of at least one rock drilling machine (10, 10?), a support unit (13) for connection to and support of a rotator unit (12), a boom unit (11) between the rotator unit (12) and the feed beam unit (8) for displacement of the feed beam unit in planes essentially at right angle to a main plane (P) for the support unit (13), wherein the rotator unit (12) is arranged for rotating the feed beam unit (8) around an axis (A), which is essentially-perpendicular to said main plane (P), wherein the support unit (13) is connectable to a vehicle unit being part of the rock drill rig (5), and being arranged for displacing the rock drill rig. The support unit (13) has joint connecting elements (14) being sidewardly connectable for connection to a sidewardly directed carrier device (15, 17) which is attachable to the vehicle unit, and a lower abutment side (16) for lying supporting against an outer substrate.

Abstract: The present invention provides a power tool that can be used at a position away from the external power source. The power tool includes a housing, a motor, an end tool, a battery pack, and an inverter. The housing has an upper side portion and a lower side portion. The motor is supported by the housing and driven by alternate-current power. The end tool is supported by the housing and rotatably driven by the motor. The battery pack outputs direct-current voltage. The inverter is disposed on the upper side portion and at a position higher than the motor and configured to convert the direct-current voltage outputted from the battery pack into alternate-current voltage and to supply the motor with alternate-current power.

Abstract: A vibratory pile driver configured to insert curved sheet pile beneath a conduit by rotating the pile driver about a fixed pivot element to advance the curved sheet pile along a fixed arc. In one exemplary embodiment, the distance between the fixed pivot element and the clamps that secured the curved sheet pile to the pile driver is the same as the radius of curvature of the curved sheet pile. In another exemplary embodiment, when the curved sheet pile is secured to the pile driver by the clamps, the center of the radius of curvature of the curved sheet pile lies substantially on the rotational axis of the fixed pivot element. In this embodiment, the vibratory pile driver may be rotated about the fixed pivot element to advance the curved sheet pile along an arc having curvature substantially identical to the radius of curvature of the curved sheet pile.

Abstract: The present invention relates to a drop hammer assembly including a drop hammer configured with at least two end conditions, characterized in that the position of the end conditions can be reversed when required. Also claimed is a method of reversing the drop hammer with respect to the drop hammer housing.

Abstract: A carburetor includes a passageway having a constricted section, a nozzle directed into the passageway proximate the constricted section, and a shaft having a surface that at least partially defines the constricted section. The nozzle is configured to deliver fuel to air passing through the passageway, and the surface includes a contour that is configured to be moved relative to the passageway to change the area of the passageway through the constricted section.

Abstract: The invention relates to an arrangement for employing a drill steel centralizer travelling on a feed beam of a rock drill machine. The drill steel centralizer has a pressure fluid-operated actuator for closing a transfer opening intended for a drill rod during drilling, whereby pressure fluid is fed into the actuator during drilling.

Abstract: A clamp system for an elongate member, comprising first and second clamp members, an actuator member, and an actuator system. The actuator member defines an actuator cam surface and is supported for movement between first and second actuator positions. The second clamp member defines a clamp cam surface and is supported for movement between first and second clamp positions. The actuator system displaces the actuator member between first and second actuator positions. As the actuator member moves from the first actuator position to the second actuator position, the actuator cam surface engages the clamp cam surface to cause the second clamp member to move towards the first clamp member, thereby clamping a portion of the elongate member between the first and second clamp members.

Abstract: An apparatus and method for fencing in which a mobile apparatus has a plurality of posts held with wires passing through respective aligned holes and means to take a post at a time to an into the ground driver with the wire or wires still extending through apertures in the post.

Abstract: The invention relates to a cement silo structure for a mining machine comprising a mixer, a cement silo for cement and a feed apparatus for feeding cement to the mixer. The cement silo is a separate unit that may be transferred by means of transfer means between a use position on top of the mining machine and a filling position that differs from the use position.

Abstract: An apparatus and method for the subterranean support of underground conduits is disclosed, including a pile driver that is configured to connect to an articulated boom of an excavator or another unit of positioning machinery to insert a section of curved sheet pile beneath a conduit. In one exemplary embodiment, the pile driver has a head portion and a body portion. The head portion of the pile driver is connected to the excavator and the body portion of the pile driver is moveable relative to both the head portion of the pile driver and the excavator to allow the pile driver to properly orient a section of curved sheet pile for insertion into subterranean material beneath an underground conduit.

Abstract: A system for mounting a lead assembly on a construction machine including a set of leads having a driver that is slidably mounted to the set of leads. The system further includes at least one lifting component for engaging the driver and moving the driver on the leads, and a pivotable mounting assembly mounted to the set of leads and adapted to adjust the position of the set of leads. Moreover there is a quick connecting portion adapted to engage the pivotable mounting assembly and the construction machine so as to allow for the quick engagement and disengagement of the construction machine from the set of leads.

Abstract: The invention relates to a drilling implement with a derrick, a drill drive for driving a drill rod guided on the derrick and a gear, which is placed between the drill drive and drill rod for transmission purposes. According to the invention, for inverting the gear ratio, the gear is placed in disengageable and reversible manner on the drill drive.

Abstract: A telescoping leader for a construction vehicle for accommodating a vibrator, pile driver, earth drilling gear mechanism, or the like, has an outer leader that is disposed so that it can be longitudinally displaced relative to an inner leader. The inner leader and outer leader have closed material cross-sections, and the outer leader surrounds the inner leader. At the end of the outer leader that can be displaced on the inner leader, and at the end of the inner leader that is guided in the outer leader, a guide is firmly disposed, on which the outer leader can be displaced.

Abstract: A mechanical fence post driver for attachment to a lift arm of a standard front-loader which includes a mounting plate, guide tube, and roller latch assembly. The guide tube receives a tee or other fence post inserted therein such that it contacts the mounting plate. The fence post is held in place by a roller latch assembly which compresses the post against the rearward side of the guide tube. Insertion of the fence post into the ground is accomplished by lowering the lift arm while the post is held within the guide cylinder. A rotation plate assembly may be positioned between the mounting plate and guide cylinder to provide a convenient mechanism to rotate the guide cylinder in relation to the mounting plate.

Abstract: A pile driver includes a leader rotation/holding mechanism that can firmly hold a leader in a rotatable state and also reliably rotate the leader using a general-purpose, inexpensive hydraulic motor by keeping the hydraulic motor from action of a bending moment from the leader. The pile driver has a leader revolver that includes a mechanism for rotating a leader. The leader revolver includes an outer tube and an inner tube that is concentrically arranged inside the outer tube via a pair of tapered roller bearings provided at two upper and lower positions. A lower part of the leader is connected, in an integrally rotatable state, to an upper part of the inner tube protruding upward from an upper end opening of the outer tube. A hydraulic motor is placed in a lower part of the leader revolver.