Abstract: To stabilize a drill string and to reduce or prevent wellbore deviation in directional drilling, weight rods by which weight is to be applied to drill bit are maintained free-standing and under compression within a drill string while the drill string itself is maintained in tension to limit or prevent lateral deviation of the weight rods in compression. Weight provided by the weight rods is transferred to the drill bit through a load transfer member in compression connected between the drill string and the drill bit.

Abstract: A non-rotating drill string is formed from a plurality of independent, cylindrical sections pivotally connected together by a latch mechanism. The adjacent ends are partially beveled such that the sections can bend in a single direction. Means are disclosed for varying the effect of the beveled surfaces, thus controlling the angle of bend for a given one of the sections. A downhole mud motor (PDM) drives the drill bit through the use of a flexible drive shaft running through the center of a metal-lined, neoprene drilling fluid hose which runs through the interior of the independent cylindrical sections. The total curvature of the borehole drilled by the system equals the sum of the angles of bend between the individual sections.

Abstract: Improved drill collars and their manufacture include the assembly of a body member formed of an appropriate high strength material, and a liner within the body. The body member will provide the majority of the strength and weight required of the drill collar, while the liner will be constructed of a material offering improved resistance to corrosion and stress corrosion cracking. The liner may be formed of a metal alloy, and may be retained within the body member by deforming the liner radially outwardly to establish an interference fit with the interior bore of the body member. A sealant may also be placed with the collar between the liner and the body member to seal any space between the two members.

Abstract: A drill bit latch assembly for releasably securing an earth drill bit to the bottom end of a drill string comprises a tubular housing adapted to be secured to the bottom end of a tubular drill string, drill bit holder adapted to be secured to a drill bit, and a latch assembly. The drill bit holder is telescopically movably received in one end of the housing and coupled thereto for rotation with the housing. The latch assembly is telescopically received in the other end of the housing. The latch assembly releasably engages the holder and is operative with the housing for maintaining the holder in a predetermined operative position within the housing. The latch assembly is responsive to an unlatching tool lowered down the drill string to unlatch the holder.

Abstract: A debris catcher comprising a conical screen (filter) in a drill string which defines an annular accumulation space between the screen and the inner wall of the drill string is presented. The central portion of the screen is open to establish an unimpeded flow path. A centrifugal deflector, impeller or similar device above (upstream from) the screen establishes a helical flow pattern in the drilling mud whereby debris entrained in the mud is forced outwardly by centrifugal action. The debris is then caught in the annular accumulation space between the screen and the drill string wall when the mud flows through the screen. If the accumulator fills or the screen becomes clogged, mud will still flow through the center flow passage. The debris catcher of the present invention is preferably positioned within a drill string upstream of a mud powered turbine or other device in the mud stream, the operation of which may be jeopardized by debris in the mud stream.

Abstract: A direct drive for well drilling tools is established which includes a friction bearing with a trace ring and a bearing ring. The bearing ring has a number of bearing segments distributed around its periphery. These bearing segments are supported so that they can be tilted and shifted axially. Each bearing segment includes a support part mounted in a bore of the bearing ring and a compression spring rod arranged in the bore of the bearing ring to provide tilting and axial shifting of the segment against a spring force.

Abstract: Drill steel or bit apparatus includes a primary drill bit having a base and a stem, a drill tip, and a bore extending longitudinally through the base, the stem, and the tip, and a pilot drill bit having a base and a stem, and a tip, and the stem and the tip extend through the longitudinal bore in the primary drill bit. The pilot drill bit includes a longitudinally extending bore through which compressed air flows. The base of the pilot drill bit is impacted by a drill piston and the base of the pilot drill bit in turn impacts the primary drill bit. Drilling is accomplished by the tips of both the pilot drill and the primary drill bit.

Abstract: A borehole tool employs a drill string having a plurality of sections of drill pipe connected together for traversing a wellbore. Drilling fluid is circulated down the drill string and up the annulus between the drill string and the wellbore to transport entrained drill cuttings out of the wellbore. At least one section of double wall drill pipe with its outer wall perforated, is included in the drill string. Drilling fluid flow down the string into the section of double wall drill pipe is controlled to effect a desired degree of drilling fluid flow rate through the perforations in the outer wall of the double wall drill pipe section so as to provide a stirring action to the drill cuttings in the wellbore annulus and thereby improve the transport of entrained drill cuttings out of the wellbore in the circulating drilling fluid.

Abstract: An improved drill pipe utilizing multi-conduit tubulars is provided. A seal subassembly (644) is constructed and arranged so as to receive a plurality of similar tubular conduits (626, 630). The similar tubular conduits (626, 630) are inserted into both ends of the seal subassembly (644). At one end, the tubular conduits (630) are threadably attached to the seal subassembly (644), while at the opposite end, the tubular conduits (626) are slidably attached to the seal subassembly (644). T-rings seals (674) are provided to insure sealing engagement of the tubular conduits to the seal subassembly (644). A collar (638) is provided to join a drill pipe (596) to one end of the seal subassembly (644). A lift subassembly (682) is provided to attach the other end of the seal subassembly (644) to another drill pipe (598). The seal subassembly (644) is constructed so as to allow the tubular conduits to be of strength sufficient to withstand pressure and compression forces only.

Abstract: A chuck to be power driven for rotating drill bits in the mining and construction fields. The chuck is designed to drive one or more telescoped drill steels which carry a mining bit and is designed to drive drill steels with square drive ends, large hexagonal drive ends, small hexagonal drive ends and large and small hexagonal ends as well as roof bolt units without modification.

Abstract: A device for reducing the break-out torque in a drill pipe tool joint selectively can be disabled so that break-out is at standard torque. The torque reducing device includes a collar located on the pin. The collar has a makeup shoulder that makes up against the makeup shoulder of the box of the drill pipe. The collar has a pair of ramp rings that will slide relative to each other during break-out torque. When they slide, they reduce the overall vertical height, allowing the collar to move vertically from the makeup shoulder a slight distance to reduce the torque. A split ring encircles the ramp rings for urging the ramp rings back to the initial position. A pin engages a slot in the split ring. The pin can be rotated between locked and unlocked positions to prevent the split ring from expanding. This prevents the ramp rings from operating.

Abstract: An apparatus for propelling a plurality of pipes arranged in series comprises basic thrusting means for generating a thrust to be applied to the pipes and intermediate thrusting means for receiving the thrust from the basic thrusting means and applying the received thrust to one of the pipes. The intermediate thrusting means includes a press head provided with a portion displaceable to a position where the portion is capable of abutting against the rear end face of one of the pipes when the intermediate thrusting means is advanced while displaceable to another position where the portion does not interfere with the advance of the following pipes when the intermediate thrusting means is removed and an intermediate body extending rearward from the press head such as to receive the thrust from the basic thrusting means and apply the received thrust to the press head.

Abstract: A mining drill bit for attachment to a hollow drill steel is provided with water openings in the head thereof on either side of a planar cutting member in close proximity to the leading edges thereof. Preferably the water openings are in addition radially and axially proximate to the chisel edge of the cutting member. Water injected into the end of a bore hole through the water openings efficiently removes drillings from the vicinity of the cutting member. Two planar slurry surfaces formed on diametrically opposite sides of drill bit head and truncating the circumference of the head at the base thereof so as to form chordal lips funnel water injected into the end of the bore hole and cuttings removed from the vicinity of the cutting member away from the end of the bore hole for removal therefrom in two localized columns of high velocity flow that scour accumulations of cuttings from the walls of the bore hole.

Abstract: A power tool combination including a hammer drill, an adapter secured to the drill for attaching it to an elongated rod which bears on the floor, a pneumatic cylinder and piston unit mounted between the elongated rod and the drill for applying an uniform external force for moving the power drill into the ceiling, and a coupling member between the pneumatic piston and cylinder unit. The coupling member is rigid for transmitting axial forces therethrough under normal operating conditions but is capable of yielding to absorb abrupt shock forces in the event that the drill encounters an undesirable obstruction in the ceiling, the coupling member including structure for causing it to return to a normal rigid condition after the shock forces have been absorbed.

Abstract: There is disclosed an adjustable bent sub for use in directional drilling in earth formations which is adapted to be placed between the power unit and bearing assembly components of a downhole motor and which can be angularly adjusted without requiring disassembly of the downhole motor unit.

Abstract: Polycrystalline diamond wear surfaces in bearing structures are maintained at temperatures that prevent thermal degradation in spite of exceptionally high loads. This temperature control is accomplished by segmenting the diamond wear surface to provide interrupt channels through which the energy build-up at the diamond wear surface is maintained below the thermal degradation level. Cooling fluid may be caused to flow through the interrupt channels, the higher the velocity of fluid flow around the diamond bearing surface, the greater the cooling effect.

Abstract: A roof-drilling system for use in subterranean mining applications and the like in which the drill head of a roof drilling machine is arranged such that the receiving cavity of its chuck is configured having a lost motion association with the drive-in portion of starter and driver drill steel rods. The lower surface of a retainer fixed to the drill head and having a non-circular aperture formed therein serves to define one bearing surface for utilizing the drill head itself to pull the assemblage of drill steel from a completed bore. To remove the drill steel driver component from the drill head chuck, the miner grasps the lowermost portion and rotates it a relatively small amount. To provide for interlocking of various components of the drill steel, i.e.

Abstract: A substantially homogeneous heavy wall drill pipe and its method of manufacture are disclosed. A cylindrical ingot is placed in a multi-hammer forging press to form the ingot into a drill pipe bar having a central protector portion and upper and lower connector sections each of larger diameter than cylindrical body sections of the drill pipe. Thereafter, the bar is straightened and upper and lower end connectors are machined. Threaded end portions are machined on the connectors and a bore is drilled through the drill pipe bar.

Abstract: For use in a wellbore, a connector assembly for connection to and use with a variety of downhole tools and apparatuses and methods for effecting such use; and tools including such a connector assembly in combination and methods for the use of such tools. The connector assembly has a T-shaft with shoulders extending therefrom and a slot cylinder for receiving, holding, and supporting the T-shaft. Slots and recesses are provided in the slot cylinder for receiving, transmitting and encompassing the T-shaft's shoulders.

Abstract: Bearing rings containing PCD faced bearing inserts are mounted adjacent tungsten carbide radial bearing surfaces at the ends of respective bearing sleeves attached to the drive shaft of a down hole well drilling motor, thereby preventing excessive wear at the extremities of the radial bearing surface in controlled and steerable drilling applications.

Abstract: A drill collar is disclosed having a fishing neck just behind the pin end, which has a reduced dimension compared with the box end. Hence, the tool is particularly well suited for being oriented with its pin end up in a drill string. The BSR is enhanced while the collar retains good "fishability", and "washoverability", characteristics.

Abstract: A method and apparatus for setting an underwater conductor pipe in which the conductor pipe is lowered into the wellhole on a drill string as the borehole is being formed by a drill bit and underreamer positioned at the end of the drill string below the end of the conductor pipe. The drill string and conductor pipe are detachably interconnected by a housing latch which includes means for detachably securing the drill string and drilling assembly to the conductor pipe. The drill string is provided with an upper latch sub, which retains and supports the drill string in its fully extended position within the conductor pipe, and a lower latch sub which retains and supports the drill string in the retracted position. As the apparatus is lowered a drill motor actuates the drilling assembly such that the well hole is formed in the ocean floor. Drilling continues until the permanent guide base of the conductor pipe engages the ocean floor.

Abstract: A drill steel for percussion drilling has four longitudinally extending grooves for removal of cuttings. The grooves are shaped such that, in comparison with a hexagonal drill steel, there is obtained an enlarged space for cuttings and a less consumption of material with maintenance of the same resistance to bending.

Abstract: The present invention relates to a seat protector device of the type which may be employed with drill rods for transmission of thrust from a driving member to a driven member. More specifically, the invention relates to an improved drill rod system for earth drilling where the rod also provides an axial passageway for a fluid to carry drill cuttings away from the cutting area. The seat protector device of the present invention may be detachably inserted between one or more drill rod sections and/or between one of the drill rods and the drill bit and/or between one of the drill rod members and the driving chuck for transmitting thrust load forces while simultaneously reducing damage and/or wear between the component parts.

Abstract: An adjustable bent sub for use in directional drilling in earth formations comprises a first body member having a first body portion defining a first primary axis and a second body portion defining a first secondary axis disposed at a first offset angle with respect to the first primary axis, a second body member having a first body portion defining a second primary axis and a second body portion defining a second secondary axis disposed at a second offset angle with respect to the first primary axis, the second body member being adapted to be secured to the first body member such that the first secondary axis and the second primary axis are coaxial and define a common axis and the second body member is rotatable about the common axis. A device is provided for non-rotatably coupling the second body member to the first body member in predetermined angular relation about the common axis so as to provide a predetermined angular relationship between the first primary axis and the second secondary axis.

Abstract: A downhole drive shaft and bearing structure having a unitary, generally cylindrical housing with a radial bearing surface affixed to its interior; a drive shaft having a radial bearing surface affixed to its exterior and thrust bearing inserts mounted at the bit end thereof; and a drive shaft cap affixed to the drive shaft and carrying thrust bearing inserts, the thrust bearing inserts of the cap and drive shaft interfacing with oppositely disposed inserts mounted in the housing.

Abstract: An apparatus and method for interconnecting a drill collar and a stabilizer in axial alignment is disclosed. The tool includes an upper plate and a lower plate held in spaced, parallel relationship to one another with the upper plate having a plurality of peripheral holes around it. A plurality of rods project between the upper and lower plates, each one of the rods being mounted at a bottom end to the lower plate and inserted adjacent its top end in sliding relationship through one of the peripheral holes in the upper plate. A spring is placed around each of the rods for biasing the top plate away from the lower plate, and an attachment pin projects downwardly from the lower plate for insertion into a kelly pin hole on an oil rig. A stabilizing pin projects upwardly from the upper plate, and a rotatable plate is rotatably secured to that stabilizing pin intermediate the ends of the stabilizing pin.

Abstract: The invention relates to a safety connection for drilling purposes, especially for oil wells. The connection comprises two portions (1,2) which, during normal drilling, transmit the torque and the thrust required for the tool to operate, said torque and thrust being transmitted via a drive cone (11) and fluting (10). In the event of the tool becoming jammed downhole, strong axial traction breaks calibrated traction links (4) at a predetermined force, thereby separating said two portions (1, 2) and making it possible to abandon downhole solely the tool and the connection portion (1) connected thereto.

Abstract: Disclosed is a two piece drill chuck for use with downhole drills and the like. The new chuck features a replaceable wear collar portion which permits optimum material selection and heat treatment for each part of the chuck thereby extending its useful life. By expanding the wear collar slightly beyond the drill diameter and extending it axially rearward an improved measure of protection is also afforded to the drill casing.

Abstract: A roof-drilling system for use in subterranean mining applications and the like in which the drill head of a roof drilling machine is arranged such that the receiving cavity of its chuck is configured having lost motion association with the drive-in portion of starter and driver drill steel rods. The lower surface of a retainer fixed to the drill head and having a non-circular aperture formed therein serves to define one bearing surface for utilizing the drill head itself to pull the assemblage of drill steel from a completed bore. To remove the drill steel driver component from the drill head chuck, the miner grasps the lowermost portion and rotates it a relatively small amount. To provide for interlocking of various components of the drill steel, i.e.

Abstract: A dual conduit drill string used in drilling holes for geothermal, oil and gas wells, and the like, comprises a removable inner conduit to permit the use of salvage or repair equipment within the outer conduit. The outer conduit comprises standard API drill pipe sections which are each slightly modified to receive the removable inner conduit sections. Each inner conduit section is provided with flexible hangers for suspending the weight of the inner conduit from a support ledge formed on the interior surface of the drill pipe. The hangers permit upward removal motion and rotation of the inner conduit with respect to the drill pipe, but prevent downward motion. Individual inner conduit sections are joined together at lockable stab joints in which locking is accomplished by the rotatable engagement of a key and locking socket. Preferably, the inner conduit is manufactured in uniform lengths and mounted in drill pipe sections of non-uniform lengths by means of drill pipe adaptor subs.

Abstract: The invention disclosed herein concerns a drill stem intended for sinking shafts in the ground, especially for the oil and natural gas industry. It has on its outer periphery a surface of revolution providing a succession of hollow profiles with a rounded shape relative to the axis of the stem, said surfaces for revolution being adapted to rest against the internal faces of complementary shape of self-gripping slips which ensure holding of the drill string.

Abstract: A soil and rock drill adapter intended for coupling a rotatable drill rod to a drill bit, optionally with intermediate percussion drilling means or compressed-air drilling means, is arranged to permit the drill bit to be positioned eccentrically in relation to the longitudinal axis of the drill rod. To this end the adapter comprises two mutually connecting parts arranged one above the other and abutting each other in a plane extending at right angles to the longitudinal axis of the drill rod, and means being provided which enable two adapter parts to be adjusted relative one another between an eccentric position and a centric position relative to said axis.

Abstract: A substantially homogeneous heavy wall drill pipe and its method of manufacture are disclosed. A cylindrical ingot is placed in a multi-hammer forging press to form the ingot into a drill pipe bar having a central protector portion and upper and lower connector sections each of larger diameter than cylindrical body sections of the drill pipe. Thereafter, the bar is straightened and upper and lower end connectors are machined. Threaded end portions are machined on the connectors and a bore is drilled through the drill pipe bar.

Abstract: An easy break-out tool joint (10) (two embodiments) comprising a drive spindle (stem), or sub (12, 12a) having a shoulder ring (32, 32a) whose shoulder (34) is axially movable but rotatable with the sub (12, 12a) to form a conventionally shouldered (34, 58) drill pipe joint so that, upon rotation in one direction, torque is applied in the conventional manner for drilling or back reaming. The shoulder (34) is initially axially moved relative to the drive sub to disconnect the shoulder (34, 58) when the drive stem is rotated in the opposite, or break-out direction, thereby reducing the torque required for break-out to only that torque necessary to unthread the joint. In the practice of the method of triple back reaming utilizing this easy break-out tool joint, a drilling unit (140, 160) is lowered to the platform and the drive spindle or sub (12, 12a) is connected to the top drill pipe of the string, while the string is held by a spider (156) at the platform level.

Abstract: A rigid, stiffened downhole motor assembly for drilling a vertical wellbore of increased straightness wherein substantially more weight can be applied to the drill bit driven by the motor without subjecting the case of the motor to those compressive and/or bending forces previously experienced by known downhole motors in similar drilling operations. The present assembly comprises a housing of heavy-walled conduit which is coupled to the lower end of a tool string. A downhole motor, e.g. a "mud" motor is positioned within the housing and is operably coupled thereto by a means which allows the weight of the housing to be transferred to the drill bit without subjecting the motor case to compressive or bending forces. Also, an annulus is provided between the housing and the case of the motor so that a greater volume of drilling fluid can be flowed through the tool string to thereby provide better cooling of the bit and better removal of cuttings from the wellbore.

Abstract: An automatic drive lock drill system for roof drilling with a bit and drill steel components which are assembled axially one by one in telescoping relationship when the acircular drive shank on one part is inserted into an acircular recess in an adjacent part. The drive shank on each component has a series of radial lobes on the corners of the acircular part which are spaced at a set location from the end of the shank and will fit into the recess grooves and undercut ribs of the adjoining part and when rotated in either drive or reverse direction, each lobe of each male shank will automatically interlock on an axial plane, when rotated from an insertion orientation to a drive orientation.

Abstract: A drive device for driving a drill bit for drilling bore holes in underground formations comprises a tubular housing for attachment to a drill string with a rotary drive means in the housing arranged to be driven by fluid forced through the housing. The rotary drive means drives an output shaft for connecting to a drill bit, the output shaft being supported by at least one axial bearing which comprises a continuous bearing ring and a retaining ring carrying a plurality of bearing segments which are swivellingly mounted to provide for a spacing of reducing cross-section between the bearing surfaces so that relative rotation of the bearing ring and bearing segments causes fluid to flow into the space and build up a hydrodynamic lubricating film.

Abstract: A liquid-filled collar for applying weight to the nether end of a tool string which is to be used in a wellbore filled with wellbore liquid. The collar has an annulus formed between inner and outer conduits which annulus is at least partially filled with a dense liquid having a density greater than that of the wellbore liquid. The annulus is open at the top to the wellbore liquid so that the head of the wellbore liquid acts on the head of the dense liquid in the annulus to exert a force on the bottom closure of the annulus to produce a downward force greater than the upward buoyant force of the wellbore liquid. Low density liquid having a density less than the wellbore liquid can fill a portion of the annulus below the dense liquid to provide buoyancy for the collar when used in horizontal wellbores.

Abstract: Method and apparatus for Percussive drilling, in which a drill rod is selected with dimensions such that cross-sectional areas of an inner channel within the rod for flushing medium, and of an outer channel formed between the rod and material being drilled, are substantially equal, so that flow resistance of the drill particles and consumption of flushing powder are reduced.

Abstract: A milling tool for removing a packer from a well includes a releasable catcher for supporting remains of a milled packer (51). The catcher has a sleeve (26) with deflectable fingers (29) which normally support the remains of the packer. If the packer should become stuck, the fingers (29) press on a release ring (39) which has a ramp (43) that engages a complementary ramp (42) on a shoulder (41) on the mandrel (14) of the mill. The ramps cam the ring outwardly until the ring breaks in tension at a deliberately weakened location (52). This releases the sleeve (26) to slide downwardly and permit the fingers (29) to deflect inwardly into a recess (23), thereby clearing the bore of the stuck packer.

Abstract: An adapter for detachably mounting a drill bit on an extension, is described as having a button-type catch with outwardly diverging flanges, and a separate, split ring of spring steel for exerting a spring biasing force against the button catch. The button catch is seated in a recess which is formed in the split ring. In another embodiment of the invention, the split ring is provided with a protruding finger for initially holding the button catch, so that it can be easily inserted within the bore of the drill bit extension, prior to the final positioning of the adapter within the bore.

Abstract: A remotely releasable pipe connector is described and comprises a first tubular connector or "pin connector" having at least one laterally extending locking member, and a slotted second tubular connector or "box connector" cooperatively disposable over the first tubular connector with the slots thereof removably engaging the first tubulars connector's locking members. One or more shear plates are attachable to the second tubular connector and are positioned to prevent the release of the locking members from the slots in the second tubular connector until the shear plates are subjected to a force greater than or equal to a predetermined force.

Abstract: A device for use in underground drilling comprising:a tubular housing,a down-hole motor mounted within the housing and having an output shaft,means for connecting said output shaft to a drill bit,means for connecting said housing to a drill string,first and second stabilizers mounted on said housing,said first stabilizer being mounted nearer than the second stabilizer to the output shaft connecting means,at least one of said stabilizers being an eccentric stabilizer, andat least one stress relieving means between the first stabilizer and the means for connecting the housing to the drill string.

Abstract: A flexible drill pipe adapted for connection in a drill string, having sufficient wall thickness in order to withstand forces imposed by drilling a well. The flexible pipe has a plurality of cuts defining interlocking teeth and recesses on axially adjacent segments of the pipe, the teeth in one segment being positioned in the recesses of, and interlocking with the teeth of, the adjacent segment. Each of the teeth includes a generally semicircular crown section, two essentially flat shoulders and a tapered base portion, with the curved, tapered sides of circumferentially adjacent bases forming the semicircular recesses for receiving the crowns of axially adjacent interlocking teeth.

Abstract: An external gauge carrier for use in tubing-conveyed drill stem testing comprises a protective housing for locating and securing the pressure measuring and recording system. The gauge carrier may be manufactured from drill collar bar stock but provides a 1--1 interface with ordinary drill pipe, other measurement subs, perforating guns and the like; i.e., to the complete system it "looks" like a drill collar. The gauge measures and records drill stem bore pressure while providing "full bore" testing capabilities, i.e., the gauge carrier allows unimpeded wireline operation therethrough and causes essentially no pressure drop throughout its length. Special machining and gauge placement is required in order to provide the above capabilities and features while still maintaining sufficient wall thickness to ensure structural integrity. A unique system for protecting the relatively delicate gauges from damage due to shocks from pressure surges is also disclosed.

Abstract: A downhole bearing assembly includes concentric inner and outer tubes, with bearings mounted therebetween. A high pressure elastomeric cup seal assembly is mounted between the inner and outer tubes, and at least one metal-to-metal seal is mounted between the inner and outer tubes on each side of the high pressure seal assembly. A pair of pressure balancing systems are provided, each acting to minimize pressure differentials across a respective one of the metal-to-metal seals. The metal-to-metal seals protect the high pressure elastomeric seal assembly and the bearings from contamination by drilling mud, and the pressure balancing systems protect the metal-to-metal seals from excessive differential pressures.

Abstract: A soundproofing device for a drill which has an elongate shaft extending between a bit and a forged collar for attaching it to a pneumatic hammer comprises a sheath formed by a semi-rigid tube of plastics material adapted to surround the shaft without touching it. This sheath extends between sealed first mounting ring near the bit and second mounting ring near the hammer. These mounting ring are free to move relative to the shaft in rotation and in translation. Tests show a reduction in the noise level 5 m from the drill from 102 dBA to 89 dBA.

Abstract: The invention relates to a coupling between a drill bit (7) and a drill shaft (6), which at least in an end position in one rotation direction gives an interlocking free from play between the elements, whereby simultaneously the drill bit (7) can be freely rotated in relation to the drill shaft (6) in opposite rotation direction. The drill bit (7) is at the inside provided with a helical spline (11) in which a parallel helical spline (10) arranged on the drill shaft (6) is engaged. The axial motion of the drill bit (7) is delimited by aid of a joint consisting of a peripheric notch (9) cut into the drill shaft (6) and a pin (8) firmly connected to the drill bit (7). The splines (10, 11) have the same pitch s, which is greater than the sum of the spline widths b'+b", and this brings about that the drill bit (7) can be freely rotated on the drill shaft (6) between two end positions.

Abstract: A drill pipe joint for insertion in a drill pipe comprises a body having an axial bore therethrough and comprising generally cylindrical upper and lower portions and a widened cylindrical intermediate portion at the upper end of which at least three cutouts are formed for insertion therein of removable attached members each provided with an upwardly directed internal passage connecting the bore to an interchangeable nozzle mounted in the upper end of the passage and situated on a diameter intermediate the outside diameter of the intermediate portion and that of the upper portion of the body.The joint is particularly suitable for passing through a zone in which circulation is lost and is arranged in the drill pipe string above the level of the zone of lost circulation.