CA1160214A - Shank adaptor for rock-drilling machines - Google Patents
Shank adaptor for rock-drilling machinesInfo
- Publication number
- CA1160214A CA1160214A CA000362899A CA362899A CA1160214A CA 1160214 A CA1160214 A CA 1160214A CA 000362899 A CA000362899 A CA 000362899A CA 362899 A CA362899 A CA 362899A CA 1160214 A CA1160214 A CA 1160214A
- Authority
- CA
- Canada
- Prior art keywords
- adaptor
- flushing hole
- flushing
- hole
- shank
- 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
- 238000005553 drilling Methods 0.000 title claims abstract description 7
- 238000011010 flushing procedure Methods 0.000 claims abstract description 67
- 238000005452 bending Methods 0.000 abstract description 4
- 230000003247 decreasing effect Effects 0.000 abstract description 3
- 238000005255 carburizing Methods 0.000 description 3
- 206010016825 Flushing Diseases 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 208000010392 Bone Fractures Diseases 0.000 description 1
- 206010017076 Fracture Diseases 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
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
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
-
- 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
- E21B17/03—Couplings; joints between drilling rod or pipe and drill motor or surface drive, e.g. between drilling rod and hammer
Landscapes
- 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)
- Closures For Containers (AREA)
Abstract
ABSTRACT
The invention is concerned with a shank adaptor for a rock-drilling machine provided with at least one side flushing hole which connects an axial flushing hole of the adaptor with the outside thereof and which, together with the axial flushing hole, serves as a passage for transporting flushing medium. The side flushing hole has an oblong cross-sectional shape with the longitudinal axis of the oblong parallel to the longitudinal axis of the shank. The shank adaptor of the invention enables stress concentration at the outer edge of the side flushing hole to be reduced while decreasing hole-edges sensitive to fractural impressions by half, which also results in a reduction in the probability of fatigue cracks caused thereat by the rotary bending forces on the adaptor.
The invention is concerned with a shank adaptor for a rock-drilling machine provided with at least one side flushing hole which connects an axial flushing hole of the adaptor with the outside thereof and which, together with the axial flushing hole, serves as a passage for transporting flushing medium. The side flushing hole has an oblong cross-sectional shape with the longitudinal axis of the oblong parallel to the longitudinal axis of the shank. The shank adaptor of the invention enables stress concentration at the outer edge of the side flushing hole to be reduced while decreasing hole-edges sensitive to fractural impressions by half, which also results in a reduction in the probability of fatigue cracks caused thereat by the rotary bending forces on the adaptor.
Description
The present invention relates to a shank adaptor for rock-drilling machines provided with at least one side flushing hole whose axis preferably lies in the same plane as the axis of the adaptor and which connects the axial flushing hole of the adaptor with the outside thereof, and which side flushing hole, together with the axial flushing hole, serves as a transport passage for flushing medium.
Hydraulically operated machines are now used to an ever increasing extent in connection with rock drills.
These machines develop large forces, causing the drill to be sunk to great depths, which requires efficient removal of the drill sludge, i.e. effective flushing of the drill.
In order to effectively flush away the sludge from the drill the flushing medium must be maintained at a very high pres-sure, said medium normally being water or air. In order to ensure an efficient seal at the loca-tion where the flushing medium is introduced into the shank adaptor, there is arranged around said adaptor a flushing head into which the flushing medium is introduced and from where said medium passes into the axial flushing hole of the adaptor through two circular side flushing holes, which may be drilled at right angles to the axial direction of the adaptor or drilled at an oblique angle thereto. This type of flushing, with a special flushing head around the adaptor, is called separate flushing.
The disadvantage with these side flushing holes, however, is that they cause fractural impressions, since the
Hydraulically operated machines are now used to an ever increasing extent in connection with rock drills.
These machines develop large forces, causing the drill to be sunk to great depths, which requires efficient removal of the drill sludge, i.e. effective flushing of the drill.
In order to effectively flush away the sludge from the drill the flushing medium must be maintained at a very high pres-sure, said medium normally being water or air. In order to ensure an efficient seal at the loca-tion where the flushing medium is introduced into the shank adaptor, there is arranged around said adaptor a flushing head into which the flushing medium is introduced and from where said medium passes into the axial flushing hole of the adaptor through two circular side flushing holes, which may be drilled at right angles to the axial direction of the adaptor or drilled at an oblique angle thereto. This type of flushing, with a special flushing head around the adaptor, is called separate flushing.
The disadvantage with these side flushing holes, however, is that they cause fractural impressions, since the
- 2 -2~
stresses are particularly high in the two regions of that edge of the side flushing hole which lie in a diametrical plane through the side flushing hole at right Z~
angles to the axis of the adaptor. Consequently, frac-ture of the adaptor is often caused by fatigue cracks extending from the said two regions of the side flushing-hole edge.
The main cause of such fa-tigue cracks is that, when in operation, the adaptor is subjec-ted to rotary bending stresses which are superimposed on the s-tresses originat-ing from the shock waves.
In order to increase the wear strength and fatigue strength of the adaptor in its entirety, the adaptor is normally subjected -to heat treatment, by carburizing the same. In this way, pressure stresses are obtained in the surface layer of the adaptor bo-th axially and tangen-tially, which are intended -to coun-teract the -tensile stresses occurring in opera-tion~ It has been found, however, that this carburizing of the adaptor negatively affects the pattern of tension forces in side flushing holes of circular cross section. The tangential pressure forces namely add to the axial tension forces occurring in operation a-t the edge of the flushing hole whose diameter is at right angles to the axial direction of the adaptor. It is true that -the axial pressure forces resulting from the carburizing of the adaptor initially counteract the negative effects of the tangential pressure forces, but because of the re-orienta-tion of the s-tresses in the carburized surface zone as a result of the shock stresses occurring in opera-tion, i-t has been found tha-t the axial pressure s-tresses are rapidly reduced, and hence the aforementioned positive effect becomes negligible.
When -the side flushing hole of circular cross sec-tion are drilled at an oblique angle to the adaptor, a certain reduction in the stresses is obtained in the two afore-mentioned regions at the edge of the flushing hole lying in the diametrical plane through the flushing hole àt right angles to the axis of the adaptor, owing to the fact that the contours of the edge of said side flushing hole obtain an elliptical shape. Since, however, the side flushing hole has a circular cross section, more than one hole is required, normally two, since the circular side flushing hole can not be given an excessively large diameter, although the cross sectional area of the flushing holes must still correspond substantially to the area of the axiaL
flushing hole on the adaptor.
An object of the invention is to provide a shank adaptor provided with a single side flushing hole hav-ing a cross sectional shape such that stress concentration at the outer edge of the side flushing hole is reduced while decreasing hole-edges sensitive to fractural impressions by half, which also results in a reduction in the proba-bility of fatigue cracks caused thereat by the rotary bending forces on the adaptor.
In accordance with the present invention, there is thus provided a shank adaptor for a rock-drilling machine, provided with at least one side flushing hole which connects an axial flushing hole of the adaptor with the out-side thereof and which, together with the axial flushing hole, forms a transport passage for flushing medium. The ., .., . ~
2~4 shank adaptor of the invention is characterized in that the side flushing hole has an oblong cross-sectional shape with tho longitudinal axis of the oblong parallel to the longitudinal axis of the shank.
Preferably, the side flushing hole extends along an axis which lies in the same plane as the axis of the adaptor.
The ratio of length to width of the cross-section of the side flushing hole is preferably at least
stresses are particularly high in the two regions of that edge of the side flushing hole which lie in a diametrical plane through the side flushing hole at right Z~
angles to the axis of the adaptor. Consequently, frac-ture of the adaptor is often caused by fatigue cracks extending from the said two regions of the side flushing-hole edge.
The main cause of such fa-tigue cracks is that, when in operation, the adaptor is subjec-ted to rotary bending stresses which are superimposed on the s-tresses originat-ing from the shock waves.
In order to increase the wear strength and fatigue strength of the adaptor in its entirety, the adaptor is normally subjected -to heat treatment, by carburizing the same. In this way, pressure stresses are obtained in the surface layer of the adaptor bo-th axially and tangen-tially, which are intended -to coun-teract the -tensile stresses occurring in opera-tion~ It has been found, however, that this carburizing of the adaptor negatively affects the pattern of tension forces in side flushing holes of circular cross section. The tangential pressure forces namely add to the axial tension forces occurring in operation a-t the edge of the flushing hole whose diameter is at right angles to the axial direction of the adaptor. It is true that -the axial pressure forces resulting from the carburizing of the adaptor initially counteract the negative effects of the tangential pressure forces, but because of the re-orienta-tion of the s-tresses in the carburized surface zone as a result of the shock stresses occurring in opera-tion, i-t has been found tha-t the axial pressure s-tresses are rapidly reduced, and hence the aforementioned positive effect becomes negligible.
When -the side flushing hole of circular cross sec-tion are drilled at an oblique angle to the adaptor, a certain reduction in the stresses is obtained in the two afore-mentioned regions at the edge of the flushing hole lying in the diametrical plane through the flushing hole àt right angles to the axis of the adaptor, owing to the fact that the contours of the edge of said side flushing hole obtain an elliptical shape. Since, however, the side flushing hole has a circular cross section, more than one hole is required, normally two, since the circular side flushing hole can not be given an excessively large diameter, although the cross sectional area of the flushing holes must still correspond substantially to the area of the axiaL
flushing hole on the adaptor.
An object of the invention is to provide a shank adaptor provided with a single side flushing hole hav-ing a cross sectional shape such that stress concentration at the outer edge of the side flushing hole is reduced while decreasing hole-edges sensitive to fractural impressions by half, which also results in a reduction in the proba-bility of fatigue cracks caused thereat by the rotary bending forces on the adaptor.
In accordance with the present invention, there is thus provided a shank adaptor for a rock-drilling machine, provided with at least one side flushing hole which connects an axial flushing hole of the adaptor with the out-side thereof and which, together with the axial flushing hole, forms a transport passage for flushing medium. The ., .., . ~
2~4 shank adaptor of the invention is characterized in that the side flushing hole has an oblong cross-sectional shape with tho longitudinal axis of the oblong parallel to the longitudinal axis of the shank.
Preferably, the side flushing hole extends along an axis which lies in the same plane as the axis of the adaptor.
The ratio of length to width of the cross-section of the side flushing hole is preferably at least
3:1.
Because the cross-sectional area of the flush-ing hole in the adaptor according to the invention can be made greater, due to the fact that the hole has an oblong cross-sectional shape parallel with the axial direction of the adaptor, more than one single side flushing hole is no longer required, since the cross-sectional area of the hole can be made equal to the cross-sectional area of the - 4a -.~
~6~Z14 axial flushing hole of the adaptor. Because the side flush-ing hole n~w lies on only one side of the adaptor, the risk that the hole is located in the zone of the largest stresses, with respect to the rotary bending forces in operation, is greatly decreased.
The invention will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 is a side view of one embodiment of a shank adaptor according to the invention, and Fig. 2 shows in section the flushing hole in the adaptor of Fig. 1.
The illustrated adaptor has a hammer,surface 1 for the hammer piston of the drill machine, splines 2 for rotating the adaptor during a drilling operation, and an external screw thread 3 on which a jointing sleeve can be screwed~
Fig. 2 is a sectional view through a flushing head 4. The flushing head is not shown in Fig. 1. The flushing head encloses the side flushing hole 5 of the adaptor, said hole 5 opening out into the axial flushing hole 6. I'he head 4 is provided with an inlet connecting means 7 on which, for example, a flushing-water hose can be connected. ~he head 4 is slidably mounted on the adaptor via sealing rings 8. The side flushing hole 5 extends at right angles to the axial flushing hole 6, the hole being made by means, for example, of a shank end miller, whereby the two ends 9 obtain the form of half cylinders while the sides 10 extend parallel to the direction of the adaptor axis, the length of the hole between the two ends 9 being approximately three times the width of , .
the hole.
Although the shank adaptor according to the invention has been described with reference to a particular embodiment thereof, it is not restric ed thereto but can be modified - 5a --wi-thin the scope o:F the claims.
Because the cross-sectional area of the flush-ing hole in the adaptor according to the invention can be made greater, due to the fact that the hole has an oblong cross-sectional shape parallel with the axial direction of the adaptor, more than one single side flushing hole is no longer required, since the cross-sectional area of the hole can be made equal to the cross-sectional area of the - 4a -.~
~6~Z14 axial flushing hole of the adaptor. Because the side flush-ing hole n~w lies on only one side of the adaptor, the risk that the hole is located in the zone of the largest stresses, with respect to the rotary bending forces in operation, is greatly decreased.
The invention will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 is a side view of one embodiment of a shank adaptor according to the invention, and Fig. 2 shows in section the flushing hole in the adaptor of Fig. 1.
The illustrated adaptor has a hammer,surface 1 for the hammer piston of the drill machine, splines 2 for rotating the adaptor during a drilling operation, and an external screw thread 3 on which a jointing sleeve can be screwed~
Fig. 2 is a sectional view through a flushing head 4. The flushing head is not shown in Fig. 1. The flushing head encloses the side flushing hole 5 of the adaptor, said hole 5 opening out into the axial flushing hole 6. I'he head 4 is provided with an inlet connecting means 7 on which, for example, a flushing-water hose can be connected. ~he head 4 is slidably mounted on the adaptor via sealing rings 8. The side flushing hole 5 extends at right angles to the axial flushing hole 6, the hole being made by means, for example, of a shank end miller, whereby the two ends 9 obtain the form of half cylinders while the sides 10 extend parallel to the direction of the adaptor axis, the length of the hole between the two ends 9 being approximately three times the width of , .
the hole.
Although the shank adaptor according to the invention has been described with reference to a particular embodiment thereof, it is not restric ed thereto but can be modified - 5a --wi-thin the scope o:F the claims.
Claims (5)
1. - A shank adaptor for a rock-drilling machine, provided with at least one side flushing hole which connects an axial flushing hole of the adaptor with the outside thereof and which, together with the axial flushing hole, forms a transport passage for flushing medium, characterized in that the side flushing hole has an oblong cross-sectional shape with the longitudinal axis of the oblong parallel to the longitudinal axis of the shank.
2. - An adaptor according to claim 1, characterized in that the side flushing hole extends at right angles to the axial flushing hole.
3. - An adaptor according to claims 1 or 2, characterized in that the side flushing hole extends along an axis which lies in the same plane as the axis of the adaptor.
4. - A shank adaptor for rock-drilling machines provided with passage means for allowing transport of flushing medium through the adaptor, said passage means comprising an axial flushing hole and a side passage which connects said axial flushing hole with a flushing medium supply means located outwardly of the adaptor, said side passage having an oblong cross-sectional shape with the longitudinal axis of the oblong parallel to the longitudinal axis of the shank, wherein the ratio of length to width of said cross-section is at least 3:1.
5. - An adaptor according to claim 4, where.in there is provided only one side passage.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE79.09103-9 | 1979-11-02 | ||
| SE7909103A SE432460B (en) | 1979-11-02 | 1979-11-02 | Shank adapter for rock-drilling machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1160214A true CA1160214A (en) | 1984-01-10 |
Family
ID=20339237
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000362899A Expired CA1160214A (en) | 1979-11-02 | 1980-10-21 | Shank adaptor for rock-drilling machines |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1160214A (en) |
| NO (1) | NO152618C (en) |
| SE (1) | SE432460B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7438138B2 (en) | 2002-09-27 | 2008-10-21 | Atlas Copco Rock Drills Ab | Impact adapter for transfer of impacts and rotation from an impact rock drilling machine to a drill string |
| AU2015261161B2 (en) * | 2014-05-13 | 2019-07-18 | Sandvik Intellectual Property Ab | Shank adaptor with reinforced flushing slot |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE531086C2 (en) * | 2007-04-25 | 2008-12-16 | Atlas Copco Secoroc Ab | Device for rock drilling |
-
1979
- 1979-11-02 SE SE7909103A patent/SE432460B/en not_active IP Right Cessation
-
1980
- 1980-07-14 NO NO802118A patent/NO152618C/en unknown
- 1980-10-21 CA CA000362899A patent/CA1160214A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7438138B2 (en) | 2002-09-27 | 2008-10-21 | Atlas Copco Rock Drills Ab | Impact adapter for transfer of impacts and rotation from an impact rock drilling machine to a drill string |
| AU2015261161B2 (en) * | 2014-05-13 | 2019-07-18 | Sandvik Intellectual Property Ab | Shank adaptor with reinforced flushing slot |
Also Published As
| Publication number | Publication date |
|---|---|
| SE432460B (en) | 1984-04-02 |
| NO152618C (en) | 1985-10-23 |
| NO152618B (en) | 1985-07-15 |
| NO802118L (en) | 1981-05-04 |
| SE7909103L (en) | 1981-05-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |