AU1088000A - Thread coupling for a drill string for percussive rock drilling - Google Patents
Thread coupling for a drill string for percussive rock drilling Download PDFInfo
- Publication number
- AU1088000A AU1088000A AU10880/00A AU1088000A AU1088000A AU 1088000 A AU1088000 A AU 1088000A AU 10880/00 A AU10880/00 A AU 10880/00A AU 1088000 A AU1088000 A AU 1088000A AU 1088000 A AU1088000 A AU 1088000A
- Authority
- AU
- Australia
- Prior art keywords
- thread
- drill string
- rock drilling
- percussive rock
- thread coupling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
Description
WO 00/19057 PCT/SE99/01653 Thread coupling for a drill string for percussive rock drilling The present invention relates to a thread coupling for a drill string for percussive rock drilling. In previously known thread couplings for percussive rock drilling prestressing of the drill string elements at the contact surface between them is obtained. The increased load depends on a combination of the material deformations, which are obtained when a shock wave passes through the thread coupling, and the applied torque. The increased load increases the risk for breakage in either or both of the connected drill string elements. The present invention, which is defined in the subsequent claim, aims at achieving a thread coupling where the above mentioned load increase near the contact surface between the two drill string elements is avoided. Through this one can increase the drill rate without deteriorating the service life compared to previously known equipment. This is achieved through having a male thread with variable pitch and a female thread with a thread opening which is wider than the crest of the male thread. An embodiment of the invention is described below with reference to the accompanying drawing in which fig 1 shows a drill string with a thread coupling according to the invention. Fig 2 shows a thread joint partly in section. Fig 3 shows a part of the thread joint on a larger scale with exaggerated variation of the thread pitch. The drill string shown in the drawing comprises a drill bit 1, a drill rod 2 and a shank adapter 3. Instead of a drill rod as shown one can have several. Drill bit, drill rod and shank adapter are drill string elements. A first drill string element 3 is provided with a male thread 4 and a first impact surface 6. A second drill string element 2 is provided with a female thread 5 and a second impact surface 7. The impact surfaces 6,7 abut against each other during drilling. In the shown example the abutment is situated at the outer end of drill string element 2, so-called soulder abutment. One can of course have the abutment at the outer end of drill string element 3 instead, so-called bottom abutment. As is best shown in fig 3 the male thread 4 has an axially varying thread pitch. Furthermore the female thread 5 WO 00/19057 PCT/SE99/01653 2 has a thread opening which is wider than the crest 9 of the male thread 4. The female thread has substaantially constant pitch. Through these features the thread coupling can be tightened in spite of the threads not having the same pitch. If e.g. the female thread has a pitch of 15 mm the male thread can have a pitch which is 15+(x/15)*0.2 mm where x is a running coordinate in the longitudinal direction of the thread. In the shown example the pitch of the thread is largest near the outer end 10 of the thread 4. This means that the thread coupling is prestressed near the outer end 10 so that one avoids overloading adjacent the contact surfaces 6,7. If one instead of shoulder abutment, as shown, has bottom abutment the thread 4 has the smallest pitch near the outer end 10.
Claims (1)
1. Thread coupling for a drill string for percussive rock drilling comprising a male thread (4) and female thread (5) cooperating therewith, said male thread (4) being arranged on a first drill string element (3) and said female thread (5) being arranged on a second drill string element (2), that said first drill string element (3) comprises a first impact surface (6), that said second drill string element (2) comprises a second impact surface (7) and that said first and second impact surfaces during drilling are intended to abut against each other, c h a r a c t e r i z e d in that said male thread (4) has a variable pitch in its axial direction and that said female thread (5) has a thread opening (8) which is wider than the crest (9) of the male thread (4).
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9803268A SE515517C2 (en) | 1998-09-28 | 1998-09-28 | String drill string thread for striking rock drilling |
SE9803268 | 1998-09-28 | ||
PCT/SE1999/001653 WO2000019057A1 (en) | 1998-09-28 | 1999-09-22 | Thread coupling for a drill string for percussive rock drilling |
Publications (2)
Publication Number | Publication Date |
---|---|
AU1088000A true AU1088000A (en) | 2000-04-17 |
AU753579B2 AU753579B2 (en) | 2002-10-24 |
Family
ID=20412727
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU10880/00A Ceased AU753579B2 (en) | 1998-09-28 | 1999-09-22 | Thread coupling for a drill string for percussive rock drilling |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1117898A1 (en) |
AU (1) | AU753579B2 (en) |
CA (1) | CA2345707A1 (en) |
SE (1) | SE515517C2 (en) |
WO (1) | WO2000019057A1 (en) |
ZA (1) | ZA200102511B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3095954A1 (en) | 2015-05-22 | 2016-11-23 | Sandvik Intellectual Property AB | Drill rod or adaptor with strengthened spigot coupling |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8323348D0 (en) * | 1983-08-31 | 1983-10-05 | Hunting Oilfield Services Ltd | Pipe connectors |
GB2309276A (en) * | 1996-01-20 | 1997-07-23 | Boart Longyear Ltd | Threaded joint |
-
1998
- 1998-09-28 SE SE9803268A patent/SE515517C2/en not_active IP Right Cessation
-
1999
- 1999-09-22 AU AU10880/00A patent/AU753579B2/en not_active Ceased
- 1999-09-22 WO PCT/SE1999/001653 patent/WO2000019057A1/en not_active Application Discontinuation
- 1999-09-22 EP EP99954561A patent/EP1117898A1/en not_active Withdrawn
- 1999-09-22 ZA ZA200102511A patent/ZA200102511B/en unknown
- 1999-09-22 CA CA002345707A patent/CA2345707A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
SE515517C2 (en) | 2001-08-20 |
CA2345707A1 (en) | 2000-04-06 |
SE9803268D0 (en) | 1998-09-28 |
AU753579B2 (en) | 2002-10-24 |
SE9803268L (en) | 2000-03-29 |
WO2000019057A1 (en) | 2000-04-06 |
ZA200102511B (en) | 2002-03-27 |
EP1117898A1 (en) | 2001-07-25 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
FGA | Letters patent sealed or granted (standard patent) |