Abstract: The invention relates to an exhaust gas heat exchanger in an exhaust gas recirculation arrangement. The heat exchanger includes a plate stack which is surrounded by a housing. The plate stack can include two plates which are connected at their longitudinal edges to form a flat tube which contains a turbulator through which exhaust gas flows. The heat exchanger can also include a coolant duct which is equipped with flow directing elements arranged between two flat tubes. In order to make the exhaust gas heat exchanger more resistant to changing temperature stresses, the invention provides that the flow directing elements can be formed from a corrugated plate in which ducts with inlets and outlets are formed. At least some of the ducts in the inlet area of the coolant have a nonlinear profile so that changes in length are permitted between the plate stack and the housing.

Abstract: An automotive air conditioning system is disclosed. At the foot mode position of a rotary door 25, a gap T is formed along the door diameter between a circumferential end of a door surface 25c of the rotary door 25 and a seal rib 28 of a case 11. The flow path of a foot opening 22 communicates with a defroster opening 20 through the gap T. At the defroster mode position of the rotary door 25, on the other hand, the other circumferential end of the door surface 25c comes into contact with the seal rib 28 and closes the gap T, and the door surface 25c closes up the foot opening 22. Even upon slight rotation of the foot rotary door under the air pressure of the foot mode, therefore, the defroster blowout air amount and the foot blowout air amount are kept in a predetermined proportion.

Abstract: A self-expandable cylinder insertable into the bore of a downhole tool includes a resilient material rolled into a substantially cylindrical shape. The outside circumference of the self-expandable cylinder is variable to allow the self-expandable cylinder to be inserted into a narrowed bore of the downhole tool near the box end or pin end. Once past the narrowed bore, the outside circumference of the self-expandable cylinder self-expands within the bore of the downhole tool. The outside circumference of the self-expandable cylinder may expand to contact the inside surface of the bore. In selected embodiments, a transmission line may be routed between the bore and the outside circumference of the resilient material. The self-expandable cylinder may be effective to protect the transmission line from materials traveling through the bore.

Abstract: In a downhole well pumping system an elongated bottom standoff pipe member is connected at one end to the lower end of a well pump and includes a plug disposed at the opposite end of the standoff pipe. The standoff pipe member is adapted to rest on the wellbore bottom wall to relieve at least some of the tensile forces acting on and otherwise causing elastic stretching of the tubing string of the pumping system. The bottom standoff pipe member is preferably a smooth walled cylindrical member with fluid inlet ports and a gas relief port formed therein, respectively.

Abstract: A downhole tool is provided that includes a grip assembly for contacting a well formation. The grip assembly includes a gripper body; and a centralizer that is attached to and radially expandable with respect to the gripper body and that has a geometry which is lockable by a locking device. The grip assembly also includes a force amplifier in force transmitting relation with the centralizer, wherein the force amplifier transfers a force in a first direction to a much larger force in a second direction when the centralizer is locked by the locking device.

Abstract: The invention provides an improved method for extracting heavy oil or bitumen contained in a reservoir. The invention involves directing the formation of a solvent fluid chamber through the combination of directed solvent fluid injection and production at combinations of horizontal and/or vertical injection wells so as to increase the recovery of heavy oil or bitumen contained in a reservoir. The wells are preferably provided with flow control devices to achieve uniform production.

Abstract: A system and method for enhancing the recovery of heavy oil in an oil extraction environment by feeding nutrients to a preferred microbial species (bacteria and/or fungi). A method is described that includes the steps of: sampling and identifying microbial species that reside in the oil extraction environment; collecting fluid property data from the oil extraction environment; collecting nutrient data from the oil extraction environment; identifying a preferred microbial species from the oil extraction environment that can transform the heavy oil into a lighter oil; identifying a nutrient from the oil extraction environment that promotes a proliferation of the preferred microbial species; and introducing the nutrient into the oil extraction environment.

Abstract: A system and method for extracting hydrocarbon products from oil shale using nuclear energy sources for energy to fracture the oil shale formations and provide sufficient heat and pressure to produce liquid and gaseous hydrocarbon products. Embodiments of the present invention also disclose steps for extracting the hydrocarbon products from the oil shale formations.

Abstract: A method for fracture stimulation of a subterranean formation having a wellbore includes providing a thermoset polymer nanocomposite particle precursor composition comprising a polymer precursor mixture, dispersed within a liquid medium, containing at least one of a monomer, an oligomer or combinations thereof having three or more reactive functionalities capable of creating crosslinks between polymer chains, wherein 1% to 100% by weight of said polymer precursor mixture is obtained or derived from a renewable feedstock; and from 0.001 to 60 volume percent of nanofiller particles possessing a length that is less than 0.

Abstract: A method for assembling a stackable perforating gun system inside a well bore is provided that includes attaching a first gun section of the stackable perforating gun system to a tracking assembly, and transporting the first gun section within the well bore using the tracking assembly. The method also includes disengaging the first gun section from the tracking assembly; retrieving the tracking assembly to the surface; attaching a second gun section of the stackable perforating gun system to the tracking assembly; transporting the second gun section within the well bore using the tracking assembly; and coupling the second gun section with the first gun section using the tracking assembly.

Abstract: A firing head assembly has a sealed chamber containing a piston, a firing pin, and an impact detonator. The firing head assembly and a perforating charge are installed within a sub and the sub is secured into a string of conduit being lowered into a wellbore. After cementing the conduit, the operator drills out the cement in the conduit, disintegrating the chamber and exposing the sealed chamber to the fluid pressure of the drilling fluid in the conduit. The drilling fluid pressure causes the piston to drive the firing pin against the detonator, which detonates the perforating charge. The operator then pumps down a logging tool to survey the well. Fluid in the conduit below the pump-down head can flow out the displacement perforation into the earth formation while the logging tool is moving downward.

Abstract: The present invention is directed to a method and apparatus for providing a pathway for fluid communication through a tubing-retrievable subsurface safety valve (TRSSV). The method and apparatus are designed to be deployed within a hydrocarbon wellbore after the TRSSV has failed. The apparatus is a milling tool that is run into the wellbore and landed within the TRSSV. The milling tool comprises a housing system, a cutting system, a drive system, and an actuating system. In operation, the milling tool is landed within the housing of the TRSSV. Thereafter, the actuating system is initiated. The actuating system actuates the drive system, which in turn drives the cutting system. In one arrangement, the cutting system includes blades for shaving the pressure containing body of the TRSSV, thereby forming a pathway for fluid communication between a hydraulic fluid line and a bore of the safety valve.

Abstract: Methods are disclosed for producing an insulated electrical conductor. Electrically uninsulated portions of respective electrical conductors are connected. A joint between the electrically uninsulated portions is coated with a preceramic resin, which is heated to cure the preceramic resin into a green-state insulator that substantially covers the joint.

Abstract: A method for unloading fluids from an oil and gas well, pipeline or flowline includes using a synergistic combination of an alkyl glucoside and an amphoteric surfactant as a foaming composition. Use of the combination foaming composition improves unloading of formation fluids, particularly production fluids having natural gas condensate and water and therefore increases the rate of production from the oil and gas well.

Abstract: A method and apparatus for forming multiple lateral passages from a wellbore into a subsurface earth formation to facilitate enhancement of the production of oil, gas, heavy oil or minerals from the formation. A plurality of lateral passages are formed from a wellbore into a subsurface formation through the use of a single-run passage forming tool to minimize rig time and associated costs. A downhole indexing tool is positioned downhole and has indexing sections for positioning and indexing of a downhole well service tool and establishes precise radial orientation and location of the tool for its well servicing operation. Sequential unidirectional rotational indexing is accomplished by an indexing control stinger having a J-slot indexing system defining a circumferential slot section defining a desired number of indexing positions that are sequenced responsive to linear reciprocating movement of the indexing control stinger.

Abstract: A connector for securing a first cylindrical member to a second cylindrical member comprises a cylindrical body which includes a first end that is attached to the first member and a second end that is positioned proximate the second member, a cylindrical housing sleeve which is positioned concentrically over the body and which includes an upper end portion that is secured to the body and a lower end portion that is disposed adjacent the second member, a cylindrical primary piston that is positioned between the body and the housing sleeve, a locking mandrel which is connected to or formed integrally with the primary piston and which includes at least first and second annular portions that have different diameters, and a split lock ring which is supported by the lower end portion adjacent a number of locking grooves in the second member and which includes at least first and second cylindrical portions that correspond to the first and second annular portions of the locking mandrel.

Abstract: A corrosion-resistant alloy tube is formed and bonded to a pre-machined steel alloy rod to form a riser tensioner cylinder rod. During assembly, an epoxy is injected into an annular space between the tube and rod and then cured. The bonded tube is ground to a desired surface finish prior to installation and utilizes a double seal arrangement that prevents external pressure or corrosive fluids from entering the cured epoxy in the annular space.

Abstract: An oil and gas well production unit for the retrieval of oil and gas from a diminishing oil and gas production field. The unit comprises a well casing within the field attached to a lubricator assembly. A plunger is arranged for reciprocable travel within a tubing in the casing and the lubricator to assist in the production of oil and gas removal from the oil and gas well production unit. A plunger examination port is arranged within the lubricator assembly to permit determination of the amount of wear of the plunger without having to remove the plunger from the lubricator assembly.

Abstract: Gas lift valve designs and gas lift systems are described that feature a positive closure mechanism that is highly resistant to significant wear or damage that would result in fluid leakage. A pivotable flapper member is incorporated into a gas lift valve and used as a flow control mechanism. The flapper member provides a positive barrier to fluid flow from the production tubing to the annulus, even after substantial wear or damage.

Abstract: A downhole tool (10) comprises a body (12) defining a bore. The body includes a valve arrangement (18) including flow ports (24) in the wall of the body. The ports may be opened or closed. In addition, a variable flow restriction (30) is provided in the bore (14), the degree of restriction tending to decrease as flow across the restriction increases. The variable flow restriction may be utilised to actuate the valve arrangement.

Abstract: The present invention is directed to a combination horseshoe and impact pad that dampens the shock of impact and prevents impact pad distortion when the hoof strikes the ground. The impact pad includes a retainer member fixed to the hoof and bonded to the horseshoe top surface along the toe portion of the hoof, and a liquid cast dual-hardness polyurethane cushion member bonded to the remaining horseshoe top surface and coupled to the retainer member so that the retainer member provides a barrier that prevents the cushion member from distorting when the hoof strikes the ground.

Abstract: A harvester for root crops such as beets is provided which preferably provides continuous flow of root crops from a header, along a transfer assembly, through a processing run, and to an elevator assembly. The harvester can be configured to include or accommodate interchangeable header assemblies having different numbers of rows and/or row spacings. The transfer assembly can be of a floating type and helps to provide an even distribution of beets to the grabrollers. The processing run includes full-length cleaning grabrollers disposed parallel to the direction of travel. Modular elevator assemblies can be provided to further enhance harvester versatility. Such an approach includes interchangeable ferris wheel and scrubber chain elevator assemblies. An improved scrubber chain elevator assembly can be used which has a wraparound scrubber chain design. A pivoting tank conveyor for evenly filling a holding tank can be included.

Abstract: A harvester for root crops such as beets is provided which preferably provides continuous flow of root crops from a header, along a transfer assembly, through a processing run, and to an elevator assembly. The harvester can be configured to include or accommodate interchangeable header assemblies having different numbers of rows and/or row spacings. The transfer assembly can be of a floating type and helps to provide an even distribution of beets to the grabrollers. The processing run includes full-length cleaning grabrollers disposed parallel to the direction of travel. Modular elevator assemblies can be provided to further enhance harvester versatility. Such an approach includes interchangeable ferris wheel and scrubber chain elevator assemblies. An improved scrubber chain elevator assembly can be used which has a wraparound scrubber chain design. A pivoting tank conveyor for evenly filling a holding tank can be included.

Abstract: A shift interlock mechanism for automatically shifting a sod cutter into a low gear when a cutting blade is lowered into the ground and automatically raising the cutting blade when the sod cutter is shifted into a high gear. The mechanism may include a cutting blade lever. The cutting blade lever may include a cam member which engages the shift lever creating cam action when the cutting blade handle is raised to the up position. When the cutting blade lever is moved to lower the cutting blade, the cam member moves the shift lever into a low gear. When the cutting blade handle is in the up position and the cutting blade has been lowered, the shift lever will oppose the cam member and create an opposite cam action, thereby raising the blade, when the shifter is moved into a high gear.

Abstract: A towed scraper control system automatically lowers the scraper blade to a working position at the start of a scraping operation according to a certain method. The method includes sensing a ground speed of the vehicle and sensing a draft force applied by the scraper to the vehicle. With the vehicle pulling the scraper at or near a target ground speed over terrain with the blade positioned above a surface of the ground, the blade is automatically lowered with respect to the scraper frame at a first rate until the blade begins to engage the surface of the ground. Thereafter, while the vehicle continues to move forward at or near the target ground speed, the blade is lowered with respect to the frame at a second rate and for a duration related to the sensed ground speed so that lowering of the blade stops when the scraper wheel begins to enter a cut produced by the blade.

Abstract: An impact rotary tool is provided that is switchable between an impact mode where the tool delivers an impacting torque on an output tool and a drill mode where the driver delivers a smooth output on an output tool. The impact rotary tool includes an impact mechanism and a hammer block that in the impact mode is movable parallel to the axis of the driver shaft and delivers reciprocating blows to rotate an anvil and in the drill mode substantially constantly engages the anvil. The impact mechanism includes a stopper that does not contact the hammer block in the impact mode and engages the hammer block in the drill mode to maintain the substantially constant contact between the hammer block and the anvil.

Abstract: The instant invention, the fence post driver and remover, is comprised of a sliding ram and a stationary ram. The stationary ram is a hollow cylinder. To begin operation of the instant invention the stationary ram is placed over the end of the fence post. That is, for operation of the instant invention the fence post slides into the hollow formed by the stationary ram so that the instant invention rests on top of the top end of the fence post. The instant invention may be used to both drive fence posts and remove fence posts. In addition, the instant invention may be used in conjunction with any elongated objects to be driven into or removed from the ground.

Abstract: A hammer drill with rolling contact at the contact surfaces for transmission of axial force between a drive shaft and wave race. By using roller bearings, line contact is obtained. The area of contact is thus close to zero as opposed to a relatively large area in engagement systems using toothed surfaces. Use of point or line contact reduces heat generation and reduces energy loss due to friction.

Abstract: A power tool comprises a housing (10;110) with an output shaft (11;111) driven by a rotation motor and an angle drive (12;112) connecting the output shaft (11;111) to the motor, wherein the angle drive (12;112) comprises a drive spindle (15;115) connected to the motor and carrying a pinion (15;115), and a bevel gear (17;117) secured to the output shaft (11;111). The drive spindle (15;115) and the pinion (16:116) are supported in the housing (10;110) via a ball type thrust bearing (24;124) having in one of its embodiments an inner ring (31) with a thread for cooperation with a threaded portion (33) on the drive spindle (15), and an outer ring (26;126) which is rigidly secured in the housing (10). The inner ring (31) is adjustable and lockable relative to the drive spindle, (15) by an annular lock element (35).

Abstract: A ground rod having an induction discharge skin-effect plate is disclosed, in which an electric current inputted into a ground rod can be easily discharged to the ground by forming an induction discharge skin-effect plate in parallel with a ground rod at a certain interval and increasing a critical surface area when a thunderbolt falls. In addition, an electric potential increase of the ground can be lowered by allowing an electric potential discharge to take place between the upper and lower vertical portions of a ground rod and an induction discharge skin-effect plate when a thunderbolt falls.

Abstract: An electrical bushing (1) for connecting a superconducting device to a device located at ambient temperature, the bushing (1) having an electrical conductor (9) and an insulating layer (10) surrounding the electrical conductor (9). An interlayer (15) is provided between the electrical conductor (9) and the insulating layer (10) and makes it possible for the electrical conductor (9) to slide in the insulating layer (10) within a temperature range of from 70 kelvin to the ambient temperature. A field control layer (11) is also applied to the insulating layer (10).

Abstract: An extension cord includes a body for connecting a two-slot socket to a three-slot socket, a detecting circuit electrically connected to the body for detecting a hot wire and a neutral wire of the two-slot socket, and a grounding circuit electrically connected to the body and mounted between the neutral wire of the two-slot socket and a grounding slot of the three-slot socket. The extension cord further includes a cable covered with a metal wire-weaved net for electrical connection with the two-slot socket. The detecting circuit includes a slide switch and an indicator. The slide switch includes a metal housing. The indicator is electrically connected in series to a resistor. The grounding circuit includes a resettable positive temperature coefficient electric fuse or a meltable fuse.

Abstract: An electromagnetic wave shielding sheet 1 comprises a transparent substrate 11, and a first anticorrosive layer 23A, a first blackening layer 25A, a metal layer 21, and a second anticorrosive layer 23B that are successively formed on the transparent substrate 11 through an adhesive layer 13. A second blackening layer 25B is formed so that it fully covers the side faces of the first anticorrosive layer 23A, the first blackening layer 25A, the metal layer 21, and the second anticorrosive layer 23B, as well as the front face of the second anticorrosive layer 23B. At least either of the first anticorrosive layer 23A and the second anticorrosive layer 23B contains one or more metals selected from nickel, chromium, and silicon, and also zinc and/or tin when it is initially formed, and the zinc and/or tin is removed from the first anticorrosive layer 23A and/or the second anticorrosive layer 23B in an intermediate steps.

Abstract: A portable electronic device including a first casing, a second casing, and a fixing element is provided. The first casing has an indentation, and the indentation has a bottom wall and at least one side wall, wherein the side wall is connected to the bottom wall. The bottom wall has a through hole, and the side wall has at least one air vent. The second casing has a fixing portion, and the fixing element has a first portion, wherein the first portion is pivoted in the through hole and connected to the fixing portion.

Abstract: A electrical box assembly is provided that includes an electrical outlet box and an adapter plate configured to accommodate electrical components in a single or double gang formation. An engaging mechanism permits the adapter plate to snap into the electrical outlet box without the use of screws or other fasteners. Thus, the adapter plate can be removed and rotated to change the orientation of the adapter plate and any electrical components attached thereto from a vertical to a horizontal orientation, and vice versa.

Abstract: A kit and corresponding methods for mechanically shimming an electrical socket as well as a pair of electrical sockets, involving a generally planar member having a front surface and a rear surface; a pair of shims formed on the rear surface; and a pair of primary orifices formed through the generally planar member for accommodating an electrical plug.

Abstract: A mounting bracket assembly for mounting an electrical box having one or more far-side supports, which fold out and contact the structure behind the bracket to provide additional stability and support. The mounting bracket assembly includes: a mounting plate having a pair of opposing sides, an opening for receiving an electrical box and a far-side support; and a mounting bracket attaching end. The far-side support has a first end, a second end and a pair of sides and includes a first section and a second section. The far-side support foldably extends from the mounting plate and the second section foldably extends from the first section. The first end of the far-side support is connected to the mounting plate and the far-side support can include a support bending aperture at the first end. The second section can include a first end, a second end and a pair of sides and the first end of the second section can have an extender bending aperture and can connect to the second end of the first section.

Abstract: A coupling loop or antenna is provided that can be used with a system that determines the resonant frequency of a sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. A cable attached to the coupling loop provides maximum isolation between the energizing signal and the sensor signal by maximizing the distance between the coaxial cables that carry the signals and maintaining the relative positions of the coaxial cables throughout the cable assembly.

Abstract: A wire harness grommet assembly includes a sheet metal panel having a speaker hole and a grommet for supporting a wire harness from an audio speaker disposed in the speaker hole. The sheet metal panel has an emboss formed along a peripheral edge of the speaker hole. The grommet has an extension portion and an attachment portion. The extension portion has a tube for supporting the wire harness therein. The attachment portion is disposed within the emboss so that an outer surface of the attachment portion is substantially continuous with an outer surface of the sheet metal panel.

Abstract: A process for manufacturing an electric cable. In particular, the process includes the steps of: a) feeding a conductor at a predetermined feeding speed; b) extruding a thermoplastic insulating layer in a position radially external to the conductor; c) cooling the extruded insulating layer; and d) forming a circumferentially closed metal shield around the extruded insulating layer. The process according to the invention is carried out continuously, i.e., the time occurring between the end of the cooling step and the beginning of the shield forming step is inversely proportional to the feeding speed of the conductor.

Abstract: Disclosed are an insulated electric wire with partial discharge resistance and a composition for manufacturing the same. The insulated electric wire with partial discharge resistance according to the present invention includes an insulating base resin constituting a basic material of an insulated electric wire; an inorganic insulator included at a content of 5 to 40 parts by weight on the basis of 100 parts by weight of the insulating base resin; and a rubbery modifier included at a content of 0.1 to 30 parts by weight on the basis of 100 parts by weight of the insulating base resin to improve flexibility of an insulated electric wire. The insulated electric wire with partial discharge resistance of the present invention may be useful to prevent occurrence of cracks caused by winding of an insulated electric wire since the insulated electric wire has a sufficient partial discharge resistance and also enhances sufficient physical properties such as flexibility, pliability, bendability, elongation, etc.

Abstract: A cable and method of forming the cable are presented. The cable contains twisted wire pairs disposed in a cavity defined by a jacket. Each wire has a conductor and an insulator surrounding the conductor. The cable may also contain a spline that separates the twisted wire pairs. At least one of the insulators or the jacket is helically corrugated such that ridges extend radially inward or outward. The ridges of the insulators may be the same or different. The cable is extruded from an extruder. The jacket may contain corrugations after being extruded by the extruder. The cable may be passed through dies to form a helically corrugated jacket. The jacket heated by a heater prior to being passed through the dies, or may pass through the dies while still hot from the extruder.

Abstract: An improved bridge-shaped molded plastic passageway to carry an automotive wiring harness over a driveshaft tunnel in an automobile chassis is disclosed. The passageway comprises conforming base and cover components joined by two parallel hinged connectors. The base and cover are molded in a co-oriented condition so the cover is right-side-up relative to the base in both the open and closed conditions. Closing the passageway is accomplished by rectilinear movement of the cover relative to the base and the connector elements are concealed within the passageway when closed. Mold height and draw are dramatically reduced by this design.

Abstract: An assembly has a conductive trace on a substrate and at least one conductor electrically coupled to the trace. First and second gaps arranged such that one gap is on either side the trace, allowing control of electrical characteristics of a signal path formed of the conductor and the trace.

Abstract: A signal feeding structure of the invention includes a circuit board and a signal feeding component. The circuit board comprises a hole. The signal feeding component comprises a fixed portion electrically welded to the circuit board, a feeding portion extending from the fixed portion for feeding signal to the circuit board, and an extending portion extending from the fixed portion and welded in the hole of the circuit board. The fixed portion and the feeding portion forms an elastic structure.

Abstract: A semiconductor device, such as a RF LDMOS, having a ground shield that has a pair of stacked metal layers. The first metal layer extends along the length of the semiconductor device and is formed on the upper surface of the semiconductor device body. The first layer has a series of regularly spaced apart lateral first slots. The second metal layer, coextensive with and located above the first metal layer, has a series of regularly spaced apart lateral second slots. The second slots overlie the spaces between the first slots, and the continuous portions of the second metal layer overlie the first slots. The slots are substantially parallel to wires extending over the ground shield. The ground shield is not limited to only two metal layers. The ground shield has a repeating unit design that facilitates automated design.

Abstract: A drilling apparatus includes a cutting structure defined by a percussive action cutter and at least one other cutter. The percussive action cutter is adapted to be urged in a drilling direction by hydraulic pressure force, while the other cutter is urged in a drilling direction by mechanical force.

Abstract: An apparatus including a drill collar having an outer surface, an assembly for interaction with an earth formation coupled to the drill collar, the assembly including a first member to extend beyond the drill collar outer surface and a second member to extend beyond the first member and toward the earth formation to receive formation fluids. An apparatus including an MWD tool having an outer surface, a formation testing assembly coupled to the MWD tool, the formation testing assembly recessed beneath the outer surface in a first position and including a piston to extend beyond the outer surface to a second position and an inner sampling member to extend beyond the piston to a third position.

Abstract: A hole coring system is provided that greatly stabilizes a tubular core drill bit for drilling into concrete or other materials enabling large diameter holes to be drilled with a handheld tool. The hole coring assembly includes a hollow drive shaft assembly that fits over a stationary mandrel that is initially installed and anchored in a pilot hole in the concrete or other material. Once the mandrel has been firmly installed as a guidepost extending rigidly out from the concrete surface, the hollow drive shaft assembly is lowered onto the mandrel. The drive shaft assembly is stabilized relative to the mandrel by means of elongated, cylindrical bearing sleeves, which may be formed of self-lubricated or fluid lubricated bearing materials. The mandrel serves as a central guidepost that ensures that a relatively large diameter, tubular core drill bit remains precisely centered relative to the guide mandrel.

Abstract: Drilling means for directional drilling in a bore hole comprising a drill pipe and a drilling head, including a slippable clutch device linking the drill pipe and said drilling head such that torque due to rotation of said drill pipe can be controllably applied to said drilling head through at least partial engagement of said clutch, and control means operable to sense an actual orientation angle of said drilling head and compare said actual orientation angle with a required orientation angle adjustably set in said control means and to control said slippable clutch such that when the actual orientation angle and the required orientation angle are the same, the slip torque of the slipping clutch equals the motor reaction torque, so maintaining the orientation angle of the drilling tool at said required orientation angle.