CA1178944A - Extension coupling for rock drilling equipment - Google Patents
Extension coupling for rock drilling equipmentInfo
- Publication number
- CA1178944A CA1178944A CA000400710A CA400710A CA1178944A CA 1178944 A CA1178944 A CA 1178944A CA 000400710 A CA000400710 A CA 000400710A CA 400710 A CA400710 A CA 400710A CA 1178944 A CA1178944 A CA 1178944A
- Authority
- CA
- Canada
- Prior art keywords
- coupling
- sleeve
- rod
- coupling rod
- screw
- 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.)
- Expired
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
Abstract
Abstract of the Disclosure An extension coupling for rock drilling equipment comprises a coupling rod having a screw-threaded portion with an outer thread whose diameter is smaller than the diameter of the non-threaded portion of the rod, and a sleeve-like part with a portion having an internal screw-thread which corres-ponds to the outer screw-thread of the rod. The sleeve includes a tubular extension which extends from the screw-threaded portion of the sleeve to the outer end thereof and which engages a part of the plain por-tion of the coupling rod. The tube provides a supporting effect which reduces the occurrence of bending stresses on the coupling.
Description
~ 178g44 The present invention relates to a coupling rod and bit extension for rock drilling equipment.
In all rock drilling operations, efforts are made to increase the efficiency of said operation, such as an increased drilling rate, i.e., an increase in the number of hole-meters or drilling-meters achieved per unit of time. The increase in efficiency sought for is primarily achieved by increasing the power of the drilling machine. When percussion drill-ing, for example, the power of the drilling machine is increased by increasing the percussion energy of the hammer of the drilling machine, and also by increasing the torque of the machine, or by increasing the pressure at which the drilling equipment is fed against the rod, or by means of a combination of these measures.
An increase in the pressure at which the drill is fed to the rock causes the drill rod or rods, which transmit percussion and/or torque energy to the rock-crushing or rock-breaking drill bit, to be subjected to powerful bending stresses which increase with increasing feed pressure and which become greater with increasing weakness of the drill rod relative to the drill bit.
In combination with other stresses and strains originating from percussion and torque, the bending stresses accelerate the occurrence of fatigue fractures in the drill rods. These fractures primarily occur in weakened or "sensitive" sections of the drill rod, for example, at the clearances in screw-thread or coupling connections, at the bottoms of the threads or in other recessed portions of the extension coupling.
In current practice, a drill bit or a coupling , sleeve is mounted onto the coupling rod via a coupling r joint, for example, screwed. It is also conventional for the length of the hollowed portion in the drill bit ~ 178944 or coupling sleeve of the joint to be somewhat shorter than the corresponding part of the rod to be inserted into said bit or sleeve.
Subsequent to assembling the extension coupling or coupling joint, there are regions behind the drill bit or in front of and behind the sleeve which are not supported by the skirt of said bit or said sleeve, and where the smaller outer diameter of the rod merges with a larger surface diameter of said rod. These regions constitute the sensitive or risk sections where fracture normally occurs as a result of the high bending stresses occurring during a drilling operation.
An object of the present invention is to provide a supporting action effective to increase the bending stresses in said sensitive or risk sections, by extending the drill bit and coupling sleeve.
To this end the extension coupling according to the invention is characterized in that a sleeve-shaped part includes an extension in the form of a non-threaded tube-shaped portion which extends from the threaded part of the sleeve-shaped portion to its outer end, and which engages a part of the coupling rod behind the screw-thread, to provide a supporting effect which decreases the bending stresses on the coupling.
In accordance with a particularly preferred embodiment of the invention, the extension coupling is characterized in that the extension having the form of a non-threaded tubular portion of the sleeve-like part has an inner diameter which is slide-fitted to the outer diameter of the non-threaded part of the coupling rod.
The extension coupling according to the - invention has the advantage of eliminating practically completely the occurrence of bending stresses at said a 1789~4 -3~
sensitive or risk sections of the drill rods, and also the dangerous fatigue effects of said bending stresses.
The extended tubular portion of the coupling sleeve has a supporting effect and because it assists in re-ducing the occurrence of harmful bending stresses in operation, it is effective in reducing the risk of fracture at the aforementioned risk sections. Tests have shown that the bending stresses can be lowered by up to 80% with-the aid of said extension.
In one aspect of the present invention, there is prov,ided an extension coupling for rock drilling equipment,,comprising a coupling rod having an end portion, a part of which is threaded, the end portion having a diameter which is smaller than the body of the coupling rod, a sleeve member having a portion provided with an internal thread portion corresponding to the threaded portion of the end portion, the sleeve member including an extended tubular portion which extends from the internal thread portion of the sleeve to the outer end of the sleeve-like part, and which engages the body of the coupling rod when mounted on the end part to provide a support for reducing the occurrence of bending stresses on the coupling, the extended tubular portion embracing a necked part on the coupling rod, between the threaded portion of the end portion and the body portion.
The invention will now be described in more detail with reference to the accompanying drawings, in which:
Figure 1 is a partial sectional view of a drill bit provided with an extended skirt in accord-ance with the invention, and Figure 2 is a partial sectional view through a coupling sleeve provided with an extended skirt in accordance with the invention.
In Figure 1 there is shown a coupling rod 1 , which is provided with a screw-thread and which has a -3a-drill bit 2 screwed thereonto. The coupling rod has a screw-threaded portion 3 which meshes with a corre-sponding screw-threaded portion 4 of the drill bit.
The drill bit has an extended tube 5, the end part of which is slide-fitted over the plain part 6 of the coupling rod, i.e., the part thereof not provided with a screw thread. Thus, the inner diameter of the tube 5 is slightly greater or substantially equal to the outer diameter of the coupling rod, while the length of said tube is such that subsequent to assembling the coupling, the tube will extend over the necked portion 7 of the coupling rod, said neck portion form-ing a weak or sensitive section, and continues up along the ~ 1789~
plain portion 6 of the coupling rod.
Figure 2 illustrates two coupling rods 8 and 9 which are also provided with a screw-thread and screwed into a coupling sleeve 10 so that the mutually opposing ends of said rods abut each other. The screw-threaded portion 12 of the coupling rod 9 meshes with the screw-threaded portion 13 of the sleeve, and the extended tube 14 of said sleeve extends over the necked portion 15 of the rod and continues up along the plain part 16 of said rod. The tube 14 is a slide fit with the plain portion 16 and thus has an inner diameter which is somewhat greater or substantially equal to the outer diameter of the plain portion 16.
Although the illustrated embodiments of the coupling extension have been described with reference to screw-threads, it will be understood that other types of screw-threads can be used, such as different types of sawtooth threads, different types of rope-threads and different types of round threads, and other types of threads.
In the embodiments illustrated in Figures 1 and 2, the extended skirt passes beyond the necked portion of the coupling rod and engages the plain part of said rod. It is also possible, however, to make the skirt shorter, so that it does not reach across the plain portion of the rod, but engages solely the necked portion or a part of said necked portion, for example, by being made a slide-fit with said portion. It is also possible to produce the coupling rod without the necked portion, in which case the plain portions 6, 16 of the illustrated embodiments are connected directly to the screw-threaded portions 3, 12. Finally, an intermediate sleeve made of a plastics or rubber material, or some other soft and damping material, can be arranged between the extended skirt and the coupling rod.
In all rock drilling operations, efforts are made to increase the efficiency of said operation, such as an increased drilling rate, i.e., an increase in the number of hole-meters or drilling-meters achieved per unit of time. The increase in efficiency sought for is primarily achieved by increasing the power of the drilling machine. When percussion drill-ing, for example, the power of the drilling machine is increased by increasing the percussion energy of the hammer of the drilling machine, and also by increasing the torque of the machine, or by increasing the pressure at which the drilling equipment is fed against the rod, or by means of a combination of these measures.
An increase in the pressure at which the drill is fed to the rock causes the drill rod or rods, which transmit percussion and/or torque energy to the rock-crushing or rock-breaking drill bit, to be subjected to powerful bending stresses which increase with increasing feed pressure and which become greater with increasing weakness of the drill rod relative to the drill bit.
In combination with other stresses and strains originating from percussion and torque, the bending stresses accelerate the occurrence of fatigue fractures in the drill rods. These fractures primarily occur in weakened or "sensitive" sections of the drill rod, for example, at the clearances in screw-thread or coupling connections, at the bottoms of the threads or in other recessed portions of the extension coupling.
In current practice, a drill bit or a coupling , sleeve is mounted onto the coupling rod via a coupling r joint, for example, screwed. It is also conventional for the length of the hollowed portion in the drill bit ~ 178944 or coupling sleeve of the joint to be somewhat shorter than the corresponding part of the rod to be inserted into said bit or sleeve.
Subsequent to assembling the extension coupling or coupling joint, there are regions behind the drill bit or in front of and behind the sleeve which are not supported by the skirt of said bit or said sleeve, and where the smaller outer diameter of the rod merges with a larger surface diameter of said rod. These regions constitute the sensitive or risk sections where fracture normally occurs as a result of the high bending stresses occurring during a drilling operation.
An object of the present invention is to provide a supporting action effective to increase the bending stresses in said sensitive or risk sections, by extending the drill bit and coupling sleeve.
To this end the extension coupling according to the invention is characterized in that a sleeve-shaped part includes an extension in the form of a non-threaded tube-shaped portion which extends from the threaded part of the sleeve-shaped portion to its outer end, and which engages a part of the coupling rod behind the screw-thread, to provide a supporting effect which decreases the bending stresses on the coupling.
In accordance with a particularly preferred embodiment of the invention, the extension coupling is characterized in that the extension having the form of a non-threaded tubular portion of the sleeve-like part has an inner diameter which is slide-fitted to the outer diameter of the non-threaded part of the coupling rod.
The extension coupling according to the - invention has the advantage of eliminating practically completely the occurrence of bending stresses at said a 1789~4 -3~
sensitive or risk sections of the drill rods, and also the dangerous fatigue effects of said bending stresses.
The extended tubular portion of the coupling sleeve has a supporting effect and because it assists in re-ducing the occurrence of harmful bending stresses in operation, it is effective in reducing the risk of fracture at the aforementioned risk sections. Tests have shown that the bending stresses can be lowered by up to 80% with-the aid of said extension.
In one aspect of the present invention, there is prov,ided an extension coupling for rock drilling equipment,,comprising a coupling rod having an end portion, a part of which is threaded, the end portion having a diameter which is smaller than the body of the coupling rod, a sleeve member having a portion provided with an internal thread portion corresponding to the threaded portion of the end portion, the sleeve member including an extended tubular portion which extends from the internal thread portion of the sleeve to the outer end of the sleeve-like part, and which engages the body of the coupling rod when mounted on the end part to provide a support for reducing the occurrence of bending stresses on the coupling, the extended tubular portion embracing a necked part on the coupling rod, between the threaded portion of the end portion and the body portion.
The invention will now be described in more detail with reference to the accompanying drawings, in which:
Figure 1 is a partial sectional view of a drill bit provided with an extended skirt in accord-ance with the invention, and Figure 2 is a partial sectional view through a coupling sleeve provided with an extended skirt in accordance with the invention.
In Figure 1 there is shown a coupling rod 1 , which is provided with a screw-thread and which has a -3a-drill bit 2 screwed thereonto. The coupling rod has a screw-threaded portion 3 which meshes with a corre-sponding screw-threaded portion 4 of the drill bit.
The drill bit has an extended tube 5, the end part of which is slide-fitted over the plain part 6 of the coupling rod, i.e., the part thereof not provided with a screw thread. Thus, the inner diameter of the tube 5 is slightly greater or substantially equal to the outer diameter of the coupling rod, while the length of said tube is such that subsequent to assembling the coupling, the tube will extend over the necked portion 7 of the coupling rod, said neck portion form-ing a weak or sensitive section, and continues up along the ~ 1789~
plain portion 6 of the coupling rod.
Figure 2 illustrates two coupling rods 8 and 9 which are also provided with a screw-thread and screwed into a coupling sleeve 10 so that the mutually opposing ends of said rods abut each other. The screw-threaded portion 12 of the coupling rod 9 meshes with the screw-threaded portion 13 of the sleeve, and the extended tube 14 of said sleeve extends over the necked portion 15 of the rod and continues up along the plain part 16 of said rod. The tube 14 is a slide fit with the plain portion 16 and thus has an inner diameter which is somewhat greater or substantially equal to the outer diameter of the plain portion 16.
Although the illustrated embodiments of the coupling extension have been described with reference to screw-threads, it will be understood that other types of screw-threads can be used, such as different types of sawtooth threads, different types of rope-threads and different types of round threads, and other types of threads.
In the embodiments illustrated in Figures 1 and 2, the extended skirt passes beyond the necked portion of the coupling rod and engages the plain part of said rod. It is also possible, however, to make the skirt shorter, so that it does not reach across the plain portion of the rod, but engages solely the necked portion or a part of said necked portion, for example, by being made a slide-fit with said portion. It is also possible to produce the coupling rod without the necked portion, in which case the plain portions 6, 16 of the illustrated embodiments are connected directly to the screw-threaded portions 3, 12. Finally, an intermediate sleeve made of a plastics or rubber material, or some other soft and damping material, can be arranged between the extended skirt and the coupling rod.
Claims (2)
1. An extension coupling for rock drilling equipment, comprising a coupling rod having an end portion, a part of which is threaded, the end portion having a diameter which is smaller than the body of the coupling rod, a sleeve member having a portion provided with an internal thread portion corresponding to the threaded portion of the end portion, the sleeve member including an extended tubular portion which extends from the internal thread portion of the sleeve to the outer end of said sleeve-like part, and which engages the body of the coupling rod when mounted on the end part to provide a support for reducing the occurrence of bending stresses on the coupling, said extended tubular portion embracing a necked part on the coupling rod, between the threaded portion of the end portion and the body portion.
2. A coupling according to claim 1, character-ized in that the extended tubular portion of the sleeve member is a uniform tube having an inner diameter which is a slide-fit with the outer diameter of the body of the coupling rod and engages therewith.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE81.02626-2 | 1981-04-24 | ||
| SE8102626A SE426089B (en) | 1981-04-24 | 1981-04-24 | CUTTING COMPOUNDS FOR MOUNTAIN DRILL EQUIPMENT |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1178944A true CA1178944A (en) | 1984-12-04 |
Family
ID=20343676
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400710A Expired CA1178944A (en) | 1981-04-24 | 1982-04-08 | Extension coupling for rock drilling equipment |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0077336B1 (en) |
| AU (1) | AU547091B2 (en) |
| CA (1) | CA1178944A (en) |
| DE (1) | DE3264233D1 (en) |
| FI (1) | FI77303C (en) |
| IE (1) | IE52613B1 (en) |
| SE (1) | SE426089B (en) |
| WO (1) | WO1982003653A1 (en) |
| ZA (1) | ZA822203B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2553171B1 (en) * | 1983-10-03 | 1988-04-08 | Dril Quip Inc | APPARATUS AND METHOD FOR CONNECTING PARTICULARLY CYLINDRICAL ELEMENTS SUCH AS TUBES |
| SE8600199L (en) * | 1986-01-17 | 1987-07-18 | Loevab Loef Och Oestlund Ab | Drilling Tools |
| US5622820A (en) * | 1988-03-10 | 1997-04-22 | City Of Hope | Method for amplification and detection of RNA and DNA sequences |
| SE522221C2 (en) | 2001-10-12 | 2004-01-27 | Sandvik Ab | Striking rock drill joints |
| JP4954542B2 (en) | 2005-12-09 | 2012-06-20 | 三菱マテリアル株式会社 | Drilling rod, drilling bit and drilling tool |
| WO2007133150A1 (en) * | 2006-05-17 | 2007-11-22 | Sandvik Intellectual Property Ab | A top hammer rock-drilling tool, a drill rod and coupling sleeve |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2122757A (en) * | 1935-07-05 | 1938-07-05 | Hughes Tool Co | Drill stem coupling |
| SE401232B (en) * | 1970-05-04 | 1978-04-24 | Sandvik Ab | THREADED CONNECTION FOR IMPACT BRUSHES |
-
1981
- 1981-04-24 SE SE8102626A patent/SE426089B/en not_active IP Right Cessation
-
1982
- 1982-03-26 AU AU82756/82A patent/AU547091B2/en not_active Ceased
- 1982-03-26 EP EP82901041A patent/EP0077336B1/en not_active Expired
- 1982-03-26 DE DE8282901041T patent/DE3264233D1/en not_active Expired
- 1982-03-26 WO PCT/SE1982/000091 patent/WO1982003653A1/en active IP Right Grant
- 1982-03-31 ZA ZA822203A patent/ZA822203B/en unknown
- 1982-04-08 CA CA000400710A patent/CA1178944A/en not_active Expired
- 1982-04-23 IE IE955/82A patent/IE52613B1/en unknown
- 1982-12-16 FI FI824324A patent/FI77303C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| WO1982003653A1 (en) | 1982-10-28 |
| FI824324L (en) | 1982-12-16 |
| IE820955L (en) | 1982-10-24 |
| DE3264233D1 (en) | 1985-08-01 |
| SE8102626L (en) | 1982-10-25 |
| IE52613B1 (en) | 1987-12-23 |
| AU547091B2 (en) | 1985-10-03 |
| ZA822203B (en) | 1983-02-23 |
| AU8275682A (en) | 1982-11-04 |
| FI77303C (en) | 1989-02-10 |
| FI77303B (en) | 1988-10-31 |
| FI824324A0 (en) | 1982-12-16 |
| EP0077336B1 (en) | 1985-06-19 |
| EP0077336A1 (en) | 1983-04-27 |
| SE426089B (en) | 1982-12-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |