Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
  • E21B17/02—Couplings; joints
  • E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
  • E21B17/042—Threaded

Definitions

• the invention relates to a threaded bushing, a use of a threaded bushing, a use of a threaded plug and a threaded connection with a threaded bushing and a threaded plug, in particular relating to a rod section for an earth drilling device.
• earth drilling device refers to devices with which the drive power of a drive device is transmitted via a rod assembly to a tool arranged on a rod assembly, particularly at the end. This includes, in particular, earth drilling devices used to drill earth bores, particularly horizontal bores, into the ground.
• the drive device generally transmits thrust or pressure forces via the rod assembly to the tool designed as a drill head. It is also possible for the earth drilling device to impart a rotary movement to the rod assembly around its longitudinal axis. Using earth drilling devices, existing bores in the ground or previously laid old pipes can be widened or extracted, and if necessary, a new pipe can be pulled in at the same time.
• Earth drilling devices are often designed so that they can be used both for creating earth bores and for pulling operations, i.e., for widening an existing bore or an old pipe, or for pulling in a new pipe.
• This makes it possible to first create a pilot bore using the same earthwork device, whereby a pilot drill head is pushed through the soil until it reaches a target excavation pit, and the pilot drill head is inserted into the target excavation pit by an expander head, whereby the pilot bore is expanded as the drill rod is retracted. If necessary, a new pipe attached to the expander head can be pulled into the expanded borehole at the same time as the expander head is retracted.
• the rod assembly of such earthwork devices usually consists of a number of rod sections, which are gradually connected to one another as the drilling progresses.
• the individual rod sections are connected via coupling elements, whereby in addition to plug-in couplings, as in DE 196 08 980
• screw connections in particular are widely used.
• the key advantages of screw connections are the low costs associated with their production and the ability to easily automate the screwing process.
• a significant disadvantage of screw connections, however, is that they often represent the weakest points in the rod assembly, which is due to the relatively small diameter in the area of the threaded connector of the threaded connection and the geometrically high stress concentration of the thread itself.
• API threads and round threads according to DIN 20 400 are also known. However, the service life of such thread forms has proven to be too short in the daily operation of earth drilling devices.
• DE 198 03 304 A1 discloses a threaded connection intended to connect rod sections of a drill rod, the drill rod being used in particular for rotary percussion drilling. Key features of these threaded connections are the asymmetrical shape of the thread with different pitch angles of the load-bearing and non-load-bearing flanks during rotary percussion drilling, as well as the provision of a threadless insertion section. The non-load-bearing flanks are also intended to be circularly arc-shaped. the DE 198 03 304 A1 The known threaded connection has proven to be insufficiently robust in daily operation.
• Threaded connections for rods of earth drilling devices are known in which the thread root forms a section of an ellipse.
• the thread shapes disclosed in this publication can be both asymmetrical and symmetrical.
• the object of the invention was therefore to create a threaded connection which, in particular, facilitates the formation and release of the connection and whose service life is impaired as little as possible or not at all.
• the idea of only having to consider a reduction of the notch effect and wanting to achieve a more homogeneous stress distribution was abandoned, which is why an elliptical shape was previously provided at the thread root, whereby the stress maxima occur less in the thread root than in the area of the flanks.
• the preferred thread form was assumed to be a simple elliptical shape, as this has a positive effect on the service life of the threaded connection, since there is usually no geometric notch in the area of the flanks and the notch effect in the thread root is thereby reduced.
• the geometry of the threaded bushing was modified such that adjacent flanks of the thread are defined by a displacement of an ellipse. This makes it possible to improve the sliding properties when screwing the screw connection, while utilizing or maintaining the advantageous properties of an elliptical shape. Damage to the thread caused by shearing or impaired thread guidance, which is commonly referred to as cold welding of the thread flanks, can be counteracted.
• the shape of the thread can be enlarged by shifting adjacent thread flanks, which are part of a section of an ellipse, whereby the elliptical shape, which has proven advantageous, is maintained with a significant change in the offset of the adjacent flanks.
• the invention provides a threaded bushing on an elongated body for a threaded connection with a threaded plug, wherein the threaded bushing has a conical internal thread in which adjacent flanks of the internal thread are formed as sections of two identical ellipses offset from one another.
• cylindrical (internal) thread encompasses a thread configuration such that the thread roots and/or thread crests of the threaded plug or threaded bushing define a shell or are arranged on a shell that has a conical shape. This allows for simple and quick screwing of the threaded plug to the threaded bushing, whereby preferably both the threaded plug and the threaded bushing have a conical thread.
• the angle that the shell, on which the thread roots and/or thread crests lie, forms with a line parallel to the longitudinal axis of the threaded plug or threaded bushing can preferably be in the range between 2° and 10°, in particular 3° and 8°, more preferably 3° and 7°.
• flank of a thread essentially encompasses the section of the thread between the root and crest. Since the shape of the flank has a curved profile due to its elliptical configuration, the assignment of the "root” and “crescent" regions is not necessarily reduced to a single point, as would be the case, for example, with a thread whose flanks are designed as straight lines. In particular, the region from an inflection point onward can be assigned to the crest, so that the flank has a section of a pure elliptical shape, whereby the region from the inflection point onward can be small. Parts of the root or the entire root of the thread can be designed as a section(s) of one or both ellipses. The root of the thread can also have a shape other than an elliptical section, which adjoins the flank in the direction of the root of the thread.
• the flank is formed as a section of an ellipse, as described, over a significant height between the thread root and the thread crest.
• the area around the, in particular geometric, center between the thread root and the thread crest can be designed as a section of the ellipse.
• the section of the ellipse can continue in both directions over a height that is between 0.2 and 0.5 times the distance from the thread root to the thread crest.
• the height at which the section of the ellipse can extend between the thread root and the thread crest can be selected to be identical for the thread of the threaded bushing or the threaded plug; in a particularly preferred embodiment, the height at which the section of the ellipse can extend between the thread root and the thread crest is different for the threaded plug and the threaded bushing of a rod assembly system. from each other.
• the height at which the section of the ellipse can extend between the thread root and thread crest of a threaded plug and a threaded bushing of a rod assembly system can be different for the threaded plug and the threaded bushing.
• the height at which the section of the ellipse extends between the thread root and thread crest in the case of a threaded plug is in the range from 0.5 to 0.9, preferably in the range from 0.6 to 0.9, preferably in the range from 0.7 to 0.9, very particularly preferably in the range from 0.75 to 0.85, of the distance between the thread root and thread crest. It can be provided that the height at which the section of the ellipse extends between the thread root and thread crest in the case of a threaded bushing is in the range from 0.5 to 0.8, preferably in the range from 0.6 to 0.7, very particularly preferably in the range from 0.63 to 0.68, of the distance between the thread root and thread crest.
• the thread root can be at least partially formed as part of the ellipse or the ellipse can extend into the thread root
• the height over which the section of the ellipse extends from the center between the thread root and the thread crest in the direction of the thread root can be up to 0.5 times the distance between the thread root and the thread crest. Since a rounding is preferably provided for the thread crest, the respective height over which the elliptical shape of the thread extends from the center between the thread root and the thread crest in the direction of the thread crest can be less than 0.5 times the distance between the thread crest and the thread root.
• the height of the extension of the section of the ellipse from the center between the thread root and the thread crest in the direction of the thread root is greater than the height of the extension from the center between the thread root and the thread crest in the direction of the thread crest.
• the section of the ellipse for a threaded plug can extend into the thread root.
• adjacent flanks refers to two flanks that are connected by exactly one thread root located between them.
• adjacent flanks can be used synonymously for "two directly consecutive flanks of the thread that are connected by a thread root located between the flanks.”
• the two adjacent flanks of the thread can be divided into a load-bearing flank and a non-load-bearing flank.
• the load-bearing flank is responsible for transmitting force from the threaded plug to the threaded bushing.
• flank(s) is/are formed as a section of an ellipse, then in the sense of the description in a preferred embodiment This means that the flank has exactly a section of an ellipse and no other shape.
• the shape of the thread root and crest are independent of this, such as a rounding in the area of the thread crest and a change in shape in the area of the thread root.
• oval in the sense of the description includes the closed oval curve, usually resulting from a conic section, which has a center point and the major and minor axes passing through the center point.
• the shape of the thread is usually viewed in a sectional view in which the threaded bushing is cut by a cutting plane that intersects the longitudinal axis of the elongated body or is contained in the cutting plane.
• the term "height" or "thread height” used to describe a thread includes the specification of a length or distance relative to the sectional plane for viewing the thread, in a direction essentially perpendicular to the longitudinal axis of the elongated body. The total height can be determined from the distance between the thread root and the thread crest. To describe the extension of the thread over the course between the thread root and the thread crest, the height over which the section of the ellipse of one of the flanks extends from the center between the thread root and the thread crest toward the thread root or the thread crest can be specified.
• offset or the adjectivally used term “offset” with regard to the two identical ellipses comprises, in the sense of the description, a spatial displacement of one of the two ellipses with respect to the other, wherein in particular at least a portion of the spatial displacement is present in a direction parallel to the longitudinal axis of the elongated body.
• the threaded bushing can be clamped against a shoulder on the threaded plug.
• the threaded plug and threaded bushing can be brought into contact with each other with their end faces, creating a force-tight connection between an end face of the shoulder and the supporting flanks, particularly those near the shoulder.
• the shoulder or end face on the threaded plug can alternatively or additionally serve as the maximum stop for the screw connection. Axial forces and/or torsional moments can also be transmitted via the shoulder or end face(s).
• the end face angle of the end faces of the threaded plug and the threaded bushing, which can come into contact with each other in the range of 65° to 85°, particularly preferably in the range of 70° to 80°. Most preferably, the end face angle of the end faces of the threaded plug and the threaded bushing, which can come into contact with each other, can be 75°.
• rod section encompasses individual, particularly rigid, directly or indirectly connectable rod sections that can be connected to one another in the longitudinal axial direction to form a drill rod or a drill string.
• the rod sections can be screwed together with a threaded plug using a threaded bushing or a threaded bushing, either mechanically interposed or without the interposition of an intermediate element.
• a rod section does not necessarily have to have a screwing element at both longitudinal ends, so it is possible for the rod section to have i) a threaded bushing at one longitudinal end and a threaded plug at the other longitudinal end, ii) a threaded bushing at each of the longitudinal ends, iii) a threaded bushing at one longitudinal end and a different type of coupling element at the other longitudinal end.
• drill string refers to several interconnected rod sections.
• a drill string which may have a drill head at its front end and, if present, a drill tip configured as a drilling tool (e.g., an expander head), can be used to drill a hole.
• a drilling tool e.g., an expander head
• earth drilling device encompasses a (and thus any) device that can move, in particular, a drill string comprising rod sections in an existing or future channel, particularly in the ground, in order to create or widen a bore, particularly a horizontal bore (HD), or to pull pipelines or other long bodies into the ground.
• the earth drilling device can, in particular, be a HD device.
• An earth drilling device can be a device that drives a drill string and can, in particular, displace soil.
• the drill string can be inserted into the ground translationally and/or rotationally in the longitudinal axial direction of the drill string.
• the drill string can be moved in the ground by tensile or compressive loading and, if necessary, also rotationally or rotatingly.
• driver element in the sense of the description comprises an element arranged on the earth drilling device, which is designed to be connected to a drill string or a rod section of the drill string in order to to exert a translational and/or rotational force on the drill string.
• a drill rod section to be connected to the drill string is engaged with the drive element, and then the drill rod section connected to the drive element is connected to the drilled drill string.
• the offset ellipses are vertical ellipses.
• a simple design can be achieved in which the flank(s) can taper into the area of the thread root to reduce the notch effect there.
• a "vertical ellipse” is understood to mean an ellipse whose major axis (i.e., the longer of the central axes) forms a larger angle with the central axis of the threaded plug or threaded bushing than its minor axis (i.e., the shorter central axis).
• the angle between the major axis of the ellipse and the central axis of the threaded plug or threaded bushing can be "corrected” for a possible inclination of the ellipse, which may be caused by the arrangement of the ellipse on a cone of the threaded plug or threaded bushing.
• the angle is preferably between 70° and 110°, preferably between 80° and 100°, and particularly preferably 90°. Deviations from this may arise, for example, due to manufacturing tolerances.
• a central axis of at least one of the two ellipses, in particular the main axis is arranged perpendicular to the longitudinal axis of the elongated body.
• This enables a particularly simple construction.
• both central axes of the two ellipses, in particular the main axis in each case are arranged perpendicular to the longitudinal axis of the elongated body.
• At least one of the thread crests of the adjacent flanks is rounded, which can reduce or eliminate sharp transitions in the thread. Most preferably, both thread crests are rounded.
• the thread root between the adjacent flanks is formed as an envelope of the two ellipses, resulting in a geometry of the thread root that reduces the notch effect and also enables a simple construction.
• envelope is understood in the sense of the description as a curve that results from a continuous connection of the two ellipse sections in the
• the thread root is formed at the intersection of the two ellipses, whereby the envelope in the area of the intersection of the two ellipses can be rounded.
• the thread design is simplified, and the notch effect in the thread root is counteracted by the geometric design.
• the offset includes at least a translational displacement in the direction of the longitudinal axis of the threaded bushing, the extent of which is between 1/8 and 1/4 of the thread height. It was surprisingly discovered that the extent of the translational displacement can be dependent on the thread height to create a screw connection with suitable properties with regard to low stress concentration and easy screwing. Very good results were achieved in this range.
• the offset includes at least a translational displacement in the direction of the longitudinal axis of the threaded bushing, the extent of which is between 1/10 and 3/10 of the distance between two adjacent thread roots.
• the offset can have at least a translational displacement in the direction of the longitudinal axis of the threaded bushing, the extent of which is between 17/100 and 25/100 of the distance between two adjacent thread roots. It has surprisingly been found that the extent of the translational displacement can be dependent on the distance between two adjacent thread roots in order to enable a screw connection with suitable properties with regard to low notch effect and easy screwing. Very good results have been achieved in this range.
• the offset includes at least a translational displacement in the direction of the longitudinal axis of the threaded bushing, the extent of which is between 1/10 and 2/10 of the quotient of the major axis and the minor axis of the identical ellipses, wherein the offset preferably includes at least a translational displacement in the direction of the longitudinal axis of the threaded bushing, the extent of which is between 12/100 and 15/100 of the quotient of the major axis and the minor axis of the identical ellipses.
• the offset of the two elliptical sections is purely a translation along the longitudinal axis of the threaded bushing. This greatly simplifies the design of the thread.
• the longitudinal axis of the threaded bushing is generally coincident with the longitudinal axis of the elongated body.
• the terms can essentially be used synonymously, although depending on the context, one term may be preferred over the other.
• the elongated body is a rod section of a drill string for an earth drilling device or a drive element for a rod section of a drill string of an earth drilling device.
• a threaded bushing on an elongated body for a threaded connection with a threaded plug is also described, wherein the threaded plug has an external thread applied to a core, in which adjacent flanks of a thread turn of the threaded plug form sections of the same ellipse, wherein a thread is used as the internal thread of the threaded bushing in which adjacent flanks of the internal thread are formed as sections of two mutually offset identical ellipses.
• the invention also provides a use of a threaded plug on an elongated body for a threaded connection with a threaded bushing, wherein the threaded bushing has a conical internal thread in which adjacent flanks of the internal thread are formed as sections of two mutually offset identical ellipses, wherein the threaded plug has an external thread applied to a core in which adjacent flanks of a thread turn of the threaded plug form sections of the same ellipse.
• the elongated body can also be a rod section of a drill string for an earth drilling device or a drive element for a rod section of a drill string of an earth drilling device.
• the invention also provides a threaded connection comprising a threaded bushing described in the present description and a threaded plug on an elongated body, wherein the threaded plug has an external thread applied to a core, in which adjacent flanks of a thread of the threaded plug form sections of the same ellipse.
• the descriptions of the individual embodiments or aspects complement each other.
• the statements regarding the threaded bushing can also apply to the aspect of a "use.”
• the statements regarding the geometry of the thread, the elongated body connected thereto, a rod section, and the like also apply to the aspect of a threaded connection in which, in addition to the described threaded bushing, a threaded plug is also present on an elongated body.
• the threaded plug has an external thread applied to a core, in which adjacent flanks of a thread pitch of the threaded plug form sections of the same ellipse.
• the threaded bushing can, to a certain extent, also interact with other threaded plugs in which adjacent flanks are not necessarily designed to correspond or complement each other. It has been recognized that a design of the threaded plug adapted to the design of the described threaded bushing may be preferred in the configuration described in the present description. Surprisingly, it has also been shown that a design of the threaded plug in which adjacent flanks form a section of one and the same ellipse can lead to a further improvement of the thread.
• the ellipse that forms adjacent flanks of the thread of the threaded plug, at least in sections, is identical to the two ellipses of the threaded bushing.
• a simple thread design is possible.
• the thread root of the threaded plug can also form a portion of the ellipse. This can also reduce the notch effect in the threaded plug.
• the thread pitch of the threaded bushing and/or the threaded plug is between 5 mm and 9 mm, preferably 7 mm.
• the cutting angle is between 20° and 30°.
• the cutting dimension of the threaded plug is at least 0.5 mm.
• the chamfer dimension of the threaded bushing is at least 1 mm.
• the difference between the length of the threaded plug and the threaded bushing is at most 0.5 mm.
• Figure 1 The right-hand side of the two views shows a section of an elongated body 1 with a threaded bushing 4 having an internal thread 5 in a sectional view.
• the threaded bushing 4 is located at the end of the elongated body 1, which is designed as a rod section of a drill string for an earth drilling device or a drive element for a rod section of a drill string of an earth drilling device.
• the right of the two representations of the Figure 1 is a sectional view of the left representation of the Figure 1 along AA.
• the left of the two representations of the Figure 1 shows a view of the threaded bushing 4 of the elongated body 1 in the longitudinal direction of the elongated body 1.
• the elongated body 1 has a longitudinal axis L.
• the internal thread 5 of the threaded bushing 4 is a conical internal thread.
• the internal thread 5 of the threaded bushing 4 is shown in an enlarged view in the Figure 2 shown.
• Figure 2 shows the internal thread 5 of the Figure 1 in an enlarged view.
• the adjacent flanks between two thread crests GS are formed as sections of two offset identical ellipses E1, E2.
• the Figure 2 shows the thread height designated GH between the thread crest GS and the thread root GG.
• the thread crest (GS) is positioned centrally between two adjacent flanks.
• the thread root (GG) is positioned centrally between two adjacent flanks.
• FIG. 3 The right-hand side of the two views shows a section of an elongated body 1 with a threaded plug 2 having an external thread 3 in a sectional view.
• the threaded plug 2 is located at the end of the elongated body 1, which is designed as a rod section of a drill string for an earth drilling device or a drive element for a rod section of a drill string of an earth drilling device.
• the right of the two representations of the Figure 3 is a sectional view of the left representation of the Figure 3 along AA.
• the left of the two representations of the Figure 3 shows a view of the threaded plug 2 of the elongated body 1 in the longitudinal direction of the elongated body 1.
• the elongated body 1 has a longitudinal axis L.
• the external thread 3 of the threaded plug 2 is a conical external thread.
• the external thread 3 of the threaded plug 2 is shown in an enlarged view in the Figure 4 shown.
• Figure 4 shows the external thread 3 of the Figure 3 in an enlarged view.
• the adjacent flanks between two thread crests GS are formed as a section of an ellipse E3.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)

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• 2023
  • 2023-01-17 PL PL23152004.0T patent/PL4403740T3/pl unknown
  • 2023-01-17 EP EP23152004.0A patent/EP4403740B1/de active Active
  • 2023-12-28 US US18/398,382 patent/US20240247553A1/en active Pending
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  • 2024-01-15 AU AU2024200253A patent/AU2024200253A1/en active Pending

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