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
  • E21B17/0426—Threaded with a threaded cylindrical portion, e.g. for percussion rods

Definitions

• Drill rods for rotary impact drilling especially for
• the present invention relates to a drill string for rotary impact drilling, in particular for overlay drilling, the individual drill rods of which have one end with an external thread and one end with an internal thread, both threads each having a larger, load-bearing flank and a smaller, non-load-bearing flank.
• the "overburden drilling” is usually carried out rotary-percussive, in which a head hammer (hammer) and a Doppelbohrgestfite be used.
• the boring bars must therefore be able to transfer impacts and torque from the hammer to the drill bit. They must also be able to be pushed together.
• Boring bars designed for overlay drilling are connected by cylindrical or conical threads. Although they have been specially developed for this application, they have numerous weak points. The most important are:
• the present invention is therefore based on the object of improving a drill pipe of the type mentioned in such a way that the aforementioned disadvantages are largely eliminated.
• the rod ends each have an unthreaded insertion section to which the external or internal thread connects, the profile of the external thread having a flattened thread tip and an arcuate thread base, while the profile of the internal thread has an arcuate thread tip and has a flat thread base, and a circumferential shoulder is formed on the rod end having the external thread, via which the impact effect can be transferred to a subsequent boring bar.
• the drill pipe according to the invention is characterized by a long service life, in particular minimal thread wear when connecting the drill rods.
• the Design of its thread ensures that self-locking is prevented even with larger thread diameters.
• An advantageous embodiment of the drill pipe according to the invention consists in that the non-load-bearing flank is each designed in the shape of a circular arc and has the same radius as the circular-arc-shaped thread tip of the internal thread or as the circular-arc-shaped root of the external thread. This helps to reduce stress peaks on the thread flanks.
• the length of the insertion section upstream of the external thread is at least 0.3 to 0.35 times the external diameter of the respective boring bar, the insertion section upstream of the external thread preferably being at least twice as long as the insertion section upstream of the internal thread.
• the circumferential shoulder on the rod end having the external thread is inclined conically in the direction of the other rod end and the other rod end has a complementarily designed end face. This increases the contact area of the shoulder, so that good impact transmission from the hammer drill to the drill bit is ensured.
• the angle of inclination of the shoulder is preferably between 10 ° and 20 ° with respect to the radial plane there the respective boring bar.
• the boring bars of the drill pipe according to the invention can be connected and released quickly and easily without self-locking if the pitch angle of the external or internal thread over the entire size range of the bars is between 12 ° and 16 °, preferably between 12.3 ° and 15.8 ° .
• load-bearing flank of the thread is inclined by 25 ° to 35 ° with respect to the central axis of the boring bar. This not only creates a relatively large contact area for the load-bearing flank, but also supports the alignment of the threads when inserting the end of the drill rod with the external thread into the end of a subsequent drill rod with the corresponding internal thread. This further minimizes wear.
• all boring bars have the same thread depth, which is between 1.5 mm and 2.5 mm, preferably approximately 2 mm. This minimizes tool costs.
• Another preferred embodiment consists in that the boring bars are graduated with respect to their outer and inner diameters such that a boring bar of a predetermined size can be inserted into the inside of a boring bar that is two sizes larger. In this way, with the drill pipe according to the invention, two or three telescopically arranged one inside the other Boring bars are drilled.
• the maximum outside diameter is preferably 1.15 to 1.55 times, preferably 1.25 to 1.45 times, the minimum inside diameter.
• the flank diameter of the external or internal thread preferably has a value in the range between 1 / 1.25 x AD and 1 / 1.05 x AD, where AD stands for the outside diameter of the boring bar. This ensures that boring bars can be inserted into boring bars of the next larger size and nevertheless have sufficient strength, because the cross-sectional area of the boring bars becomes larger at the inner end of the internal thread with increasing outside diameter of the boring bars.
• the cross-sectional area at the inner end of the internal thread is larger than the cross-sectional area at the inner end of the external thread, since in the case of boring bars in which the impact effect is transmitted via the external shoulder, the end having the internal thread is subjected to a higher bending stress than that the externally threaded end.
• the non-load-bearing flank is each designed in the shape of a circular arc, the radius of the circular arc having a value in the range between 3.2 mm and 4.5 mm, preferably approximately 3. 8 mm.
• the radius of the circular arc is for the entire size range of the boring bars maintained.
• Tapping tool can be used for the entire size range of boring bars.
• Another preferred embodiment is characterized in that the number of threads increases with increasing outside diameter of the boring bar, preferably boring bars with an outside diameter less than 75 mm one turn, boring bars with an outside diameter between 75 mm and 105 mm two turns, boring bars with an outside diameter have three threads between 105 mm and 140 mm and boring bars with an outer diameter greater than 140 mm have four threads.
• This also increases the load-bearing area of the thread flanks as the outside diameter of the boring bars increases. This ensures that when using the same thread profile for the entire size range of the boring bars, the pitch angle does not change excessively as the outside diameter (AD) increases.
• both the external and internal threads have transition radii of approximately 1 mm at all transitions.
• 2a is a profile representation of the external thread on an enlarged scale
• 2b is a profile representation of the internal thread on an enlarged scale
• Fig. 3a shows a portion of an external thread of a boring bar according to the invention with a single-start thread with a different diameter compared to Fig. 2a in side view, and
• Fig. 3b shows a portion of an external thread of a boring bar according to the invention with a two-start thread with a different diameter compared to Fig. 2a in side view.
• FIGS. 1 a and 1b show the ends of a boring bar with a cylindrical external thread 1 and a corresponding internal thread 2 in a longitudinal section.
• the boring bar ends each have a threadless insertion section 3 or 4, to which the respective one
• a circumferential outer shoulder 5 is formed at the end of the drill rod intended for rotary impact drilling, which serves to transmit the impact effect to a subsequent drill rod or the drill bit.
• the shoulder 5 is conical, specifically with an inclination angle of approximately 15 ° with respect to the radial plane, the other end of the boring bar having a complementarily beveled end face 6.
• the boring bars are graduated in terms of their outer and inner diameter in such a way that a boring bar of a predetermined size can be inserted into the interior of a boring bar which is two sizes larger.
• the maximum outside diameter AD of a boring bar is about 1.15 to 1.55 times its minimum inside diameter ID.
• the flank diameter FD of the external or internal thread is between 1 / 1.25 x AD and 1 / 1.05 x AD.
• the cross-sectional area at the inner end of the internal thread 2 thus increases with an increasing boring bar outer diameter AD.
• the cross-sectional area at the inner end of the internal thread 2 is larger than the cross-sectional area at the inner end of the external thread 1.
• the section 8 adjacent to the inner end of the internal thread 2 and the corresponding section 7 of the external thread 1 have essentially the same Wall thickness WA or WI, the inside diameter ID the boring bar widens conically in the direction of the internal thread 2.
• Figures 2a and 2b show an enlarged view of the thread profile of the drill pipe according to the invention.
• the external thread 1 and the internal thread 2 each have a load-bearing outer flank 9 and a non-load-bearing inner flank 10.
• the external thread 1 pin thread
• the internal thread 2 socketet thread
• the external thread 1 has a flattened thread tip 11 and an arc-shaped thread root 12
• the internal thread 2 socketet thread
• the external thread 1 has a flattened thread tip 11 and an arc-shaped thread root 12
• the internal thread 2 has an arc-shaped thread tip 13 and a flat thread root 14.
• the load-bearing outer flank 9 is in each case inclined by an angle ( ⁇ F of approximately 30 ° with respect to the center axis of the boring bar M.
• the non-load-bearing inner flank 10 is designed in the shape of a circular arc and has the same radius R as the circular arc-shaped thread tip 13 of the internal thread 2 or as that circular arc-shaped thread base 12 of the external thread 1.
• the radius R of the circular arc is between 3.2 mm and 4.5 mm, preferably approximately 3.8 mm.
• the transitions from the flat thread base 14 to the thread flanks 9, 10 are formed as fillet curves 15.
• the radius of these fillets 15 is approximately 1 mm. Accordingly, the transitions 16 on the external thread 1 from the flattened thread tip 11 to the thread flanks 9, 10 Rounded in a circular arc shape, the radius of the circular arc corresponding to that of the fillet curves.
• the thread depth of a thread is between 8.5 mm and 10.5 mm, preferably approximately 9.5 mm.
• FIG. 3a an external thread is shown schematically in a side view, the pitch angle ( ⁇ 1 being plotted for a single-start thread.
• Fig. 3b a side thread is schematically shown in a side view, the pitch angle ( ⁇ 2 being plotted for a two-start thread.
• the number of threads depends on the outside diameter of the boring bar. For example, boring bars with an outside diameter AD ⁇ 75 mm have one thread, while boring bars with an outside diameter AD> 75 mm and AD ⁇ 105 mm have two threads, boring bars with an outside diameter AD> 105 and AD ⁇ 140 mm have three threads and boring bars with an outside diameter AD > 140 mm have four threads.
• the thread profile of the boring bars can be not only cylindrical, but also conical.

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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)
• Drilling Tools (AREA)

Priority Applications (6)

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Citations (4)

• 1998
  • 1998-10-01 AT AT98954318T patent/ATE266796T1/de active
  • 1998-10-01 DE DE59811400T patent/DE59811400D1/de not_active Expired - Fee Related
  • 1998-10-01 KR KR1020017004213A patent/KR100556271B1/ko not_active IP Right Cessation
  • 1998-10-01 EP EP98954318A patent/EP1117897B1/de not_active Expired - Lifetime
  • 1998-10-01 WO PCT/EP1998/006264 patent/WO2000020720A1/de active IP Right Grant
  • 1998-10-01 JP JP2000574804A patent/JP3961769B2/ja not_active Expired - Fee Related

Patent Citations (4)

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