CA2178814C - An in-hole rock drilling machine - Google Patents
An in-hole rock drilling machine Download PDFInfo
- Publication number
- CA2178814C CA2178814C CA002178814A CA2178814A CA2178814C CA 2178814 C CA2178814 C CA 2178814C CA 002178814 A CA002178814 A CA 002178814A CA 2178814 A CA2178814 A CA 2178814A CA 2178814 C CA2178814 C CA 2178814C
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- Canada
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- valve
- housing
- machine
- length
- piston hammer
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Abstract
An in-hole rock drilling machine has a tubular housing (12) with a piston hammer (24) that is guided at its ends only. Its front portion is guided by a guide bushing (18) that takes support against a shoulder (13) in the housing and its rear end is guided by a valve housing (20). The guide bushing (18), the valve housing (20) and a distance tube (19) between them are clamped together against the shoulder (13) by means of a back head (22) screwed to the machine housing (12). The distance tube (19) is adapted to be compressed axially at least 0.3 pro mille of its length and preferably between 0.8 and 3 pro mille of its length when the back head is screwed into position. This arrangement gives a robust machine and to assemble and to disassemble the machine will be simple. The tolerances in length will not be critical which makes the machining of the various machine parts less critical.
Description
A1G I N-HOLE ROCK DR I Lh I BtG- MACHINE
This invention relates to an in-hole_rock drilling machine caiaprislng a tubular pausing with a guide hushing in its (rant end arranged to guide the front cad of a piston hammer and a valve hauling in the rear end of the machiae~housing-arranged to guide the rear-end of the piston hammer.
Machines of this type are known in the prior art; the machine in EP 0 394 255 is exemplary in this regard. However, machines of this type in the prior art are expensive because of the demand they place on tolerances.
It is an object of the invention to make such a- machine more simple and in particular it is an object to reduce the demands on axial tolerances and to simplify the assembling and dissassembling of such a machine.
The invention will be described with reference to the drawings which show an embodiment of the invention.
Figures 1 and 2 are together a side view of an in-hale rack drilling machine in accordance with the invention; Figure 1 shows the rear part of the machine and Figur-s 2 shows the front part. An intermediate part of the machine is act shown.
The in-hole rock drilling machine shown in the Figures has a pausing, the stain Bart of which is a cyli.adrical tube 12 that has an interior shoulder 13 and interior threads in each end. _ A drill bit I4 is maintained in the housi3g by means of a sleeve 15 screwed into the tube I2. The sleevQ 15 is in splined connectiaa with the drill bit. The drill bit is guided in the housing by the sleeve 15 and a guiding bushing -26 and a stop riag 17 prevents the drill bit from falling out. The drill bit 14 is thus axially movable a~iimited distance in the housing 12 and it cannot turn relative to the housing. In a conventional way, the drill bit 14 has am axial flushing fluid. passage that ends in flushing fluid electing ho7.es in its front surface.
This invention relates to an in-hole_rock drilling machine caiaprislng a tubular pausing with a guide hushing in its (rant end arranged to guide the front cad of a piston hammer and a valve hauling in the rear end of the machiae~housing-arranged to guide the rear-end of the piston hammer.
Machines of this type are known in the prior art; the machine in EP 0 394 255 is exemplary in this regard. However, machines of this type in the prior art are expensive because of the demand they place on tolerances.
It is an object of the invention to make such a- machine more simple and in particular it is an object to reduce the demands on axial tolerances and to simplify the assembling and dissassembling of such a machine.
The invention will be described with reference to the drawings which show an embodiment of the invention.
Figures 1 and 2 are together a side view of an in-hale rack drilling machine in accordance with the invention; Figure 1 shows the rear part of the machine and Figur-s 2 shows the front part. An intermediate part of the machine is act shown.
The in-hole rock drilling machine shown in the Figures has a pausing, the stain Bart of which is a cyli.adrical tube 12 that has an interior shoulder 13 and interior threads in each end. _ A drill bit I4 is maintained in the housi3g by means of a sleeve 15 screwed into the tube I2. The sleevQ 15 is in splined connectiaa with the drill bit. The drill bit is guided in the housing by the sleeve 15 and a guiding bushing -26 and a stop riag 17 prevents the drill bit from falling out. The drill bit 14 is thus axially movable a~iimited distance in the housing 12 and it cannot turn relative to the housing. In a conventional way, the drill bit 14 has am axial flushing fluid. passage that ends in flushing fluid electing ho7.es in its front surface.
r , ' A guide bushing 18 takes support against the shoulder 13 and a distance sleeve 19..takes.suppart against the guide bushing 18. A valve housing 20 with a back head 38 takes support against the distance sleeve 19.__ and and a tube farmed filter support 21 with a filter 21a takes support against the back s head 38 flf thewaive.housing 20. A backhead 22 of the machine housing is screwed into the rear end of the tube 12 and it is arranged to axially clamp the parts 18,29,20,38,21 against the shoulder l3.These parts 18,19,20,38,21 act ' together as a spring and their cumulative 3enght is such that they are compressed when the backhead 22 is screwed into place. .prefera'fiiy, the overall axial compression is 0.4 --2 mm. The distance sleeve 19 contributes most to this compression because of its dominating length and its comparatively small steel area in its crass section. It is adapted to be compressed at least 0.3 and preferably 0.8 - 3 pro mills of, its, l,e~gth. The filter support 21 may have about the same cross section area of steel as the distance sleeve 19, and is also adapted to be axially compressed at least 0.3 pro mills of its length, but it is shorter and its contribution to the spring action is therefore smaller.
The back 'read 38 of the valve housing 20 is.thus clamped agaiast the main part of the valve housing 20. The back head 22 of the machine housing is arranged to be screwed to a conventional drill tubing that transmits rotation to the drilling machine and also transmits hydraulic drive fluid is the form of pressure water to the drilling machine. In operation, the annular space 58 at the bac3s of the valve housiag_20 is thus continuously filled-with filtered water under pressure. When assembling the machine, one puts all the Farts 18,19,20,38,21 loosely an tap of one another which makes the assembling simple and reduces the demand an axial -talernnces. The added tolerance is taken up by the axial elastic compression. All the parts slide easily in the machine housing and are therefore easy to remove when the machiae is._te be dissassembled.
A tube 23 forms part of the valve housing 20. A piston hammer 24 with a through channel 25 has its front end guided ~
VO 95116848 3 217 8 814 p~~gE94101201 in the guide bushing 18. The rear end 27 of the piston hammer 24 extends into an annular cylinder chamber 26 (drive chamber) that is farmed in the valve housing 20 between the sleeve-like front portion 35 of the valve housing and the tube 23 of the valve housing. The rear end of the piston hammer 24 is thus guided by the walls of the cylinder chamber 26, that is, by the valve housing 20. The rear end 27 of the piston hammer 24 has a groove 28 with a rear end wall 29 so that the piston hammer 20 has a defined outer guiding surface 30 behind the end wall 29. The piston hammer 24 has also an interior guiding surface 31 of defined length. Suitably, the outer and inner guiding surfaces 30,31 could have about the same length. The actual length of the guiding surfaces is defined by the guiding surfaces 18 Cat the front end of the piston hammer) and 30,31 <at the rear end of the piston hammer) and it takes up only a minor part of the length of the piston hammer 24. The actual length of guiding is less than 20%. of the length of the piston hammer.
The ma,~or part 32 of the piston hammer 24 is between these guiding surfaces and it has a wide clearance to the distance sleeve 19 of the machine housing 12. Suitably, in order to get as heavy a piston hammer as possible, the ma,lor part 32 of the piston hammer 24 can be radially enlarged as compared with its guided end portions.
The guiding surface 33 of the piston hammer sliding against the guide bushing 18 has a smaller,diameter than the guiding surface 30 against the valve housing 20 so that the piston hammer will have a differential piston area in the front drfve chamber 34 that is formed axially between the guide bushing 18 and the valve housing 20. If the groove 28 and the front guiding surface 33 have the same diameter, then this differential area is represented by the area 36, that is, by the area of the rear wall 29 of the groove 28. This differential area is smaller than the annular piston area 37 in the rear cylinder chamber 26.
SUBSTITUTE SI~~~T
The valve housing 20 contains a spool valve 40 with three control surfaces A1,A2,A3 that are in three annular control chambers 45,46,47. The effective area of surface A3-is a differential area since the diameter of the sliding surface of the valve 40 close to the surface.-A1 is greater than the diameter of the sliding surface close to the surface A2. The relation between these areas are A3 C A1 < A2+A3 . The area A2 is greater than the area A3-and suitably, A1 and A2 can be equal or about equal and about twice as large as A3.
There is another annular chamber 48 and it is open to the -annular chamber-47 when the valve 40 is in its illustrated position. When the valve 40 is in its other position, a shoulder 49 in the valve housing separates the chambers 47 and 48. The valve 40 has a row of large holes 50 and two small holes 51.
A control conduit 52-leads between the annular chamber 46 and the rear cylinder chamber 26 and it has a control port 53 into the rear cylinder chamber 26. Another control condit 54 leads between the annular-chamber 45 and the rear drivechamber 26 and it has control ports 55 and 56 to the drive chambers 26 and 34 respectively. A number of parallel channels 57 lead axially through the valve housing 20 and connect the front drive chamber 34 with the continuously pressurized space 58 at the rear of the valve housing 20. A
number of channels 59 connect a row of ports 60 into the rear drive chamber 26 with a row of ports 61 into the annular chamber 48. A number ofchannels connect a row of ports 62 into the annular chamber 4T with the continuously pressurized space 5$ at the back of the valve housing 20.
A cycle of the operation of the machine will now be described.
Presume that the valve 40 is in its illustrated position and that the piston hammer 24 has gust begun its work stroke forwardly in order to strike the drill bit 14. C The piston hammer 24 is shown in its impacting position.) Through the SUBSTITUTE SHEET
~
VO 95!16848 217 8 814 p~lSE94101201 parts 62,61 and 60, the valve 40 connects the rear cylinder chamber 26 with the chamber 58 that is continuously under pressure. The control surface A1 of the valve is under pressure during the entire work stroke of the piston hammer 24 since the control port 56 of the control passage 54 is at first open to the continuously pressurized front drive chamber 34 and then, shortly after the closing of the port 56, the control port 55 of the control passage 54 is instead opened to the rear drive chamber 26 which is under pressure.
As shown, the length of the guide surface 30 of the piston hammer can be such that both ports 56 and 55 are closed during a short period, which, however, will be so short that it will not influence the pressure in the control passage 54. As long as the control port 53 of the control passage 52 -is closed, the valve-40 will therefore remain stable in its illustrated forward position because the area A1 overcomes the area A3. The leakage from the annular chamber 46 prevents a pressure build up in the annular chamber 46.
When the piston hammer in its work stroke opens the control port 53 of the control passage 52 ,lust after it has opened the control port 55 of the control passage 54, the passage 52 and the annular chamber 46 are pressurized , and since the area A2 that is then put under pressure equals the area Al that is already under pressure, these areas balance each other and the area A3 will force the valve into its rearward position which is not illustrated. The holes 51 in the valve 40 will he open into the annular chamber 46, but they are so small that they do not prevent the pressurization of the annular chamber 46. The leakage through the holes 51 is so small that it does not significantly influence the overall ' power efficiency. The valve 40 is dampened by its nose 65 cutting off a damping chamber so that the valve is retarded ' before it lands in its rear non-illustrated position and it will therefore not tend to rebaunce. The annular chamber 48 is cut off from the annular chamber 47 and is instead coupled to the interior of the valve through the holes 50 in the valve. Through the tube 23, the interior of the valve is SUBSTITUTE SHEET
R'O 95116848 PC1'/SE94/01201 2178814 s continuously open to-the channel 25 in the piston hammer and the channel 25 is always open to the flushing fluid passage in the drill bit 14. The rear drive chamber 26 will therefore be depressurized simultaneously with the piston hammer reaching its impacting position, and the continuously pressurized front drive chamber 34 starts to drive the piston hammer rearwardly in fts return stroke.
The relative axial positions of the control ports 53 and 55 can be varied and the control port 53 need not be axially forwardly of the part 55. -The water that flows out of the rear drive chamber 26 during the return stroke of the piston hammer 24 is thus utilized as a flushing fluid for flushing the debris out of the barehole.
When the rear drive chamber 26 is depressurlzed, the control surfaces A1 and A2 are both depressurized since both the port 55 of the control passage 52.and the port 53 of the control passage 52 will be open. to the rear drive chamber 26.
During its return stroke, the piston hammer 24 will close the ports 55 and 53. The annular chamber 46 will however remain drained; now through the small holes 51 through the valve_ Then the piston hammer 24 opens the part 56 of the control passage 54 so that the control passage 54 and the annular chamber 45 will be pressurized from the front drive chamber 34 and the surface A1 will be pressurized. Since the surface A2 is not pressurized, the surface A1 will force the valve 40 to switch to its forward position in which it is shown. During the last portion of the forward movement of the valve 40, the two small holes 51 in the valve are cut off from the annular chamber 46 and the water closed in the chamber 46 and the control passage 53 retards the valve before the valve lands since a pressurewill build up against the control surface A2. This pressure cannot be so SUBSTITUTE SI-61=~°
~O 95116848 217 8 8 l 4 p~1gE94J01201 7 _ high that it ,jeopardizes the valve staying stably in its forward position since the row of large holes 50 in the valve is close to the annular chamber 46. The leakage out through the holes 50 together with the lekage past the end of the valve 40 will be comparatively big and bfgger than the leakage into the closed part 53. The valve will now pressurize the rear drive chamber 26 via the ports 62,61,60 and the passages 59 between the ports 61 and 60 so that the piston hammer decelerates, turns and accelerates in its work stroke as previously described and the cycle is repeated.
SUBSTITUTE SHEET
The back 'read 38 of the valve housing 20 is.thus clamped agaiast the main part of the valve housing 20. The back head 22 of the machine housing is arranged to be screwed to a conventional drill tubing that transmits rotation to the drilling machine and also transmits hydraulic drive fluid is the form of pressure water to the drilling machine. In operation, the annular space 58 at the bac3s of the valve housiag_20 is thus continuously filled-with filtered water under pressure. When assembling the machine, one puts all the Farts 18,19,20,38,21 loosely an tap of one another which makes the assembling simple and reduces the demand an axial -talernnces. The added tolerance is taken up by the axial elastic compression. All the parts slide easily in the machine housing and are therefore easy to remove when the machiae is._te be dissassembled.
A tube 23 forms part of the valve housing 20. A piston hammer 24 with a through channel 25 has its front end guided ~
VO 95116848 3 217 8 814 p~~gE94101201 in the guide bushing 18. The rear end 27 of the piston hammer 24 extends into an annular cylinder chamber 26 (drive chamber) that is farmed in the valve housing 20 between the sleeve-like front portion 35 of the valve housing and the tube 23 of the valve housing. The rear end of the piston hammer 24 is thus guided by the walls of the cylinder chamber 26, that is, by the valve housing 20. The rear end 27 of the piston hammer 24 has a groove 28 with a rear end wall 29 so that the piston hammer 20 has a defined outer guiding surface 30 behind the end wall 29. The piston hammer 24 has also an interior guiding surface 31 of defined length. Suitably, the outer and inner guiding surfaces 30,31 could have about the same length. The actual length of the guiding surfaces is defined by the guiding surfaces 18 Cat the front end of the piston hammer) and 30,31 <at the rear end of the piston hammer) and it takes up only a minor part of the length of the piston hammer 24. The actual length of guiding is less than 20%. of the length of the piston hammer.
The ma,~or part 32 of the piston hammer 24 is between these guiding surfaces and it has a wide clearance to the distance sleeve 19 of the machine housing 12. Suitably, in order to get as heavy a piston hammer as possible, the ma,lor part 32 of the piston hammer 24 can be radially enlarged as compared with its guided end portions.
The guiding surface 33 of the piston hammer sliding against the guide bushing 18 has a smaller,diameter than the guiding surface 30 against the valve housing 20 so that the piston hammer will have a differential piston area in the front drfve chamber 34 that is formed axially between the guide bushing 18 and the valve housing 20. If the groove 28 and the front guiding surface 33 have the same diameter, then this differential area is represented by the area 36, that is, by the area of the rear wall 29 of the groove 28. This differential area is smaller than the annular piston area 37 in the rear cylinder chamber 26.
SUBSTITUTE SI~~~T
The valve housing 20 contains a spool valve 40 with three control surfaces A1,A2,A3 that are in three annular control chambers 45,46,47. The effective area of surface A3-is a differential area since the diameter of the sliding surface of the valve 40 close to the surface.-A1 is greater than the diameter of the sliding surface close to the surface A2. The relation between these areas are A3 C A1 < A2+A3 . The area A2 is greater than the area A3-and suitably, A1 and A2 can be equal or about equal and about twice as large as A3.
There is another annular chamber 48 and it is open to the -annular chamber-47 when the valve 40 is in its illustrated position. When the valve 40 is in its other position, a shoulder 49 in the valve housing separates the chambers 47 and 48. The valve 40 has a row of large holes 50 and two small holes 51.
A control conduit 52-leads between the annular chamber 46 and the rear cylinder chamber 26 and it has a control port 53 into the rear cylinder chamber 26. Another control condit 54 leads between the annular-chamber 45 and the rear drivechamber 26 and it has control ports 55 and 56 to the drive chambers 26 and 34 respectively. A number of parallel channels 57 lead axially through the valve housing 20 and connect the front drive chamber 34 with the continuously pressurized space 58 at the rear of the valve housing 20. A
number of channels 59 connect a row of ports 60 into the rear drive chamber 26 with a row of ports 61 into the annular chamber 48. A number ofchannels connect a row of ports 62 into the annular chamber 4T with the continuously pressurized space 5$ at the back of the valve housing 20.
A cycle of the operation of the machine will now be described.
Presume that the valve 40 is in its illustrated position and that the piston hammer 24 has gust begun its work stroke forwardly in order to strike the drill bit 14. C The piston hammer 24 is shown in its impacting position.) Through the SUBSTITUTE SHEET
~
VO 95!16848 217 8 814 p~lSE94101201 parts 62,61 and 60, the valve 40 connects the rear cylinder chamber 26 with the chamber 58 that is continuously under pressure. The control surface A1 of the valve is under pressure during the entire work stroke of the piston hammer 24 since the control port 56 of the control passage 54 is at first open to the continuously pressurized front drive chamber 34 and then, shortly after the closing of the port 56, the control port 55 of the control passage 54 is instead opened to the rear drive chamber 26 which is under pressure.
As shown, the length of the guide surface 30 of the piston hammer can be such that both ports 56 and 55 are closed during a short period, which, however, will be so short that it will not influence the pressure in the control passage 54. As long as the control port 53 of the control passage 52 -is closed, the valve-40 will therefore remain stable in its illustrated forward position because the area A1 overcomes the area A3. The leakage from the annular chamber 46 prevents a pressure build up in the annular chamber 46.
When the piston hammer in its work stroke opens the control port 53 of the control passage 52 ,lust after it has opened the control port 55 of the control passage 54, the passage 52 and the annular chamber 46 are pressurized , and since the area A2 that is then put under pressure equals the area Al that is already under pressure, these areas balance each other and the area A3 will force the valve into its rearward position which is not illustrated. The holes 51 in the valve 40 will he open into the annular chamber 46, but they are so small that they do not prevent the pressurization of the annular chamber 46. The leakage through the holes 51 is so small that it does not significantly influence the overall ' power efficiency. The valve 40 is dampened by its nose 65 cutting off a damping chamber so that the valve is retarded ' before it lands in its rear non-illustrated position and it will therefore not tend to rebaunce. The annular chamber 48 is cut off from the annular chamber 47 and is instead coupled to the interior of the valve through the holes 50 in the valve. Through the tube 23, the interior of the valve is SUBSTITUTE SHEET
R'O 95116848 PC1'/SE94/01201 2178814 s continuously open to-the channel 25 in the piston hammer and the channel 25 is always open to the flushing fluid passage in the drill bit 14. The rear drive chamber 26 will therefore be depressurized simultaneously with the piston hammer reaching its impacting position, and the continuously pressurized front drive chamber 34 starts to drive the piston hammer rearwardly in fts return stroke.
The relative axial positions of the control ports 53 and 55 can be varied and the control port 53 need not be axially forwardly of the part 55. -The water that flows out of the rear drive chamber 26 during the return stroke of the piston hammer 24 is thus utilized as a flushing fluid for flushing the debris out of the barehole.
When the rear drive chamber 26 is depressurlzed, the control surfaces A1 and A2 are both depressurized since both the port 55 of the control passage 52.and the port 53 of the control passage 52 will be open. to the rear drive chamber 26.
During its return stroke, the piston hammer 24 will close the ports 55 and 53. The annular chamber 46 will however remain drained; now through the small holes 51 through the valve_ Then the piston hammer 24 opens the part 56 of the control passage 54 so that the control passage 54 and the annular chamber 45 will be pressurized from the front drive chamber 34 and the surface A1 will be pressurized. Since the surface A2 is not pressurized, the surface A1 will force the valve 40 to switch to its forward position in which it is shown. During the last portion of the forward movement of the valve 40, the two small holes 51 in the valve are cut off from the annular chamber 46 and the water closed in the chamber 46 and the control passage 53 retards the valve before the valve lands since a pressurewill build up against the control surface A2. This pressure cannot be so SUBSTITUTE SI-61=~°
~O 95116848 217 8 8 l 4 p~1gE94J01201 7 _ high that it ,jeopardizes the valve staying stably in its forward position since the row of large holes 50 in the valve is close to the annular chamber 46. The leakage out through the holes 50 together with the lekage past the end of the valve 40 will be comparatively big and bfgger than the leakage into the closed part 53. The valve will now pressurize the rear drive chamber 26 via the ports 62,61,60 and the passages 59 between the ports 61 and 60 so that the piston hammer decelerates, turns and accelerates in its work stroke as previously described and the cycle is repeated.
SUBSTITUTE SHEET
Claims (5)
1. An in-hole rock drilling machine comprising a tubular housing (12) with a guide bushing (18) in a front end of the tubular housing (12) arranged to guide a front end of a piston hammer (24) and a valve housing (20) in a rear end of the tubular housing (12) arranged to guide a rear end of the piston hammer (24), characterized in that the guide bushing (18), the valve housing (20) and a distance tube (19) between them are clamped together against a support (13) for the guide bushing by means of a back head (22) screwed to the tubular housing (12), said distance tube (19) being adapted to be compressed at least 0.3 pro mille of its length.
2. A machine according to claim 1, characterized in that the distance tube (19) is adapted to be compressed axially at least 0.8 pro mille of its length.
3. A machine according to claim 1, characterized in that the distance tube (19) is adapted to be compressed 0.3 - 3 pro mille of its length.
4. A machine according to any one of claims 1 to 3, characterized in that an element (21) between the valve housing (20) and the back head (22) is adapted to be axially compressed at least 0.3 pro mille of its length.
5. A machine according to claim 4, characterized in that said element (21) is a filter support.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9304125A SE505170C2 (en) | 1993-12-13 | 1993-12-13 | Lowering drill with compressible spacer |
| SE9304125.9 | 1993-12-13 | ||
| PCT/SE1994/001201 WO1995016848A1 (en) | 1993-12-13 | 1994-12-13 | An in-hole rock drilling machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2178814A1 CA2178814A1 (en) | 1995-06-22 |
| CA2178814C true CA2178814C (en) | 2005-12-20 |
Family
ID=35645812
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002178814A Expired - Fee Related CA2178814C (en) | 1993-12-13 | 1994-12-13 | An in-hole rock drilling machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2178814C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105156107B (en) * | 2015-07-06 | 2017-05-17 | 中国矿业大学 | Ultrahigh-pressure rotary pulse water jet rock breaking mechanism |
-
1994
- 1994-12-13 CA CA002178814A patent/CA2178814C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105156107B (en) * | 2015-07-06 | 2017-05-17 | 中国矿业大学 | Ultrahigh-pressure rotary pulse water jet rock breaking mechanism |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2178814A1 (en) | 1995-06-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20131213 |