CA2001262C - Rock drilling method and apparatus - Google Patents
Rock drilling method and apparatusInfo
- Publication number
- CA2001262C CA2001262C CA 2001262 CA2001262A CA2001262C CA 2001262 C CA2001262 C CA 2001262C CA 2001262 CA2001262 CA 2001262 CA 2001262 A CA2001262 A CA 2001262A CA 2001262 C CA2001262 C CA 2001262C
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- drills
- forward end
- rock
- pressure fluid
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Abstract
Disclosed is a rock drilling apparatus and method for using same wherein the rock drill is a cluster of independent rock drills arranged in a circular pattern about a central axis for rotation.
The cluster drill is drawn into a hole to be drilled by a drill string in a previously drilled smaller diameter hole. The drill string provides pressure fluid to operate the cluster drill and rotation as well as the tractive force to draw the cluster drill into the hole to form a large diameter straight drilled hole. Pressure fluid and rock cuttings exit the larger diameter hole and discharge of rock particles is further aided by use of a trailing auger rotated by the cluster drill. A particular application of this device is in the production of horizontal bored holes of moderate diameter under, for example, roadways, foundations, and the like.
The drill string acting as a centering device produces a straight hole in difficult rock formations.
The cluster drill is drawn into a hole to be drilled by a drill string in a previously drilled smaller diameter hole. The drill string provides pressure fluid to operate the cluster drill and rotation as well as the tractive force to draw the cluster drill into the hole to form a large diameter straight drilled hole. Pressure fluid and rock cuttings exit the larger diameter hole and discharge of rock particles is further aided by use of a trailing auger rotated by the cluster drill. A particular application of this device is in the production of horizontal bored holes of moderate diameter under, for example, roadways, foundations, and the like.
The drill string acting as a centering device produces a straight hole in difficult rock formations.
Description
2Q1~1262 Docket No. 0529-IR-RD
ROCK DRILLING METHOD AND APPARATUS
BACKGROUND OF THE lNv~ lON
During construction it i8 often de~irable to drill horizontal holes in rock under roadways and building foundations without disturbing those structures. Such horizontal holes may be used for 05 utility services, or drainage, or the like, and for this purpose it is desirable to have a straight hole economically drilled with a minimum of ground disturbance.
To accomplish such holes it is common to dig a shaft on either side of the structure and by means of auger in soft ground, or a rock drill in harder ground, drive the hole from shaft to shaft.
This is accomplished by utilizing conventional drilling techniques which push the auger or rock drill utilizing a rotary drill string. The auger or drill and trailing drill string is inserted in sections and driven from one of the shafts to the other.
Core drills have been developed for small diameter holes which are relatively effective in drilling accurate straight holes between two locations. However, effective core drilling is limited to holes of about 4 to 8 inches or smaller because the cores must be drilled in segments, 2S usually a maximum of twenty (20) ft. and removed.
~' ~OO~Z62 Docket No. 0529-IR-RD
In larger size holes the process would be slow and the cores become increasingly difficult to remove, particularly in hard rock. As a result, a common practice has developed in boring larger 05 diameter holes to first bore a cored hole and therea~ter force a series of rotary ring reamers through ths hole to increase the hole size to the diameter deslred.
Reaming is also time-consuming and in general produces a hole which i~ rough and/or cork screwed and as the size increase~ it becomes more difficult to maintain the progress without buckling the drill string creating the rotary drive and force on the ring cutters. An improvement to thls method lS involves the pulling of the ring cutters back through the hole but since this is a progressive stepwise operation the difficulty of the reamer walking about the hole diameter, although improved, still continues.
SUMMARY OF THE I~v~NllON
In the present invention a horizontal hole is accomplished by first sinking a shaft on either side of the hole to permit access. Next, a small diameter hole between the shafts of approximately 4"
is bored by core drilling. A drill string is next inserted in the hole. A modified clustered drill, generally of the type shown and described in U.S.
Patent No. 4,729,439, entitled "Gang Drill Construction" and assigned to Ingersoll-Rand Company, the assignee of the present invention, is ~o attached to the drill string. For purposes of this :
200~262 Docket No. 0529-IR-RD
invention the center drill is removed and replaced by a section of drill rod or center feed rod which supplies the gang drill with pressure fluid from its opposite end, that is the end that normally 05 contains th~ rock cutting bits. This permits the cluster drill to b~ rQversQ mounted to th~ drill string insertQd in th~ cored drill hole. The gang drill i8 then suppliQd with pres~urQ ~luid to operate the circumferentially mounted impact rock drills. The drill string is then rotated and withdrawn through the hole tailing and rotating the cluster drill. Pressure fluid and rock drill cuttings exit the large diameter hole in the conventional manner. As an added feature, sections of auger may be attached to the back of the gang drill to effect additional cleaning of the horizontal hole as the gang drill is drawn through the hole and rotated. This will reduce the overall air requirements necessary for cleaning the hole.
It is therefore an object of the present invention to provide a method and apparatus for the drilling of accurate large diameter horizontal holes in hard rock. It is an ob;ect of the invention to drill such holes in hard rock at high speed with efficiency and minimum air consumption.
It is yet a further object to accomplish the drilling of large diameter horizontal holes in hard rock by utilizing easily modified and available cluster drills, and simple rugged and reliable boring equipment of a small size compared to similar methods for similar size holes in hard rock.
These and other objects are obtained in an apparatus for drilling larger diameter holes in hard rock comprising: a cluster drill adapted for receiving pressure fluid and rotation from a drill string at its rock - 5 impacting end, the adaptation further comprising a means for receiving pressure fluid and connecting the cluster drill to a drill string provided at the impact end of said cluster drill on its centerline, a drill string connected to the means for connecting the drill string, the drill string further rotating and drawing the cluster drill into a drilled hole containing the drill string and enlarging the hole as it progresses.
It is a further object of the present invention to include auger means attached at the back end of the cluster drill for assisting in the removal of rock particles as the cluster drill progresses through the hole. The removal being accomplished by a combination of the auger trailing and rotating with the drill and exhaust pressure fluid - 20 thereby minimizing pressure fluid consumption in the removal of rock drill particles.
According to a still further broad aspect of the present invention, there is provided a gang drill for increasing the diameter of bored holes in hard rock. The drill comprises a plurality of individual percussion producing rock drills in a cylindrical drill body. The body has a rearward end and a forward end. The forward end has bit ends of the drills exposed for rock cutting arranged peripherally around the body. A drill string is connected at the centerline of the drills to the body at its forward end and at the centerline of the drills, for rotating and drawing the drills through a previously drilled bore hole to enlarge the previously drilled hole.
- 35 The body totally encloses the drills. The body is further provided with alignment means, securing means, and means ~a~
~- 2001262 for supplying pressure fluid for each of the drills. The pressure fluid enters the drills internally of the body and exits the drills externally to the body at its forward end, whereby the body forms a peripheral passage for exiting of S the rock cuttings and provides protection for individual drills. The means for supplying pressure fluid from the forward end of the body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby provides for reversal of the direction of drilling of the gang drill.
According to a still further broad aspect, the core rod is provided with a thread at its forward end for attachment to the drill string and is connected to the rearward end of the body by attachment means. The core rod is provided with a central passage formed therein for receiving pressure fluid from the forward end of the body.
According to a still further broad aspect, the gang drill has attached at its rearward end an auger means for assisting in the clearing of drilled debris with the auger means being rotated with the drill body.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. l shows a cross section view of a clustér drill modified according to the present invention for forward pressure fluid supply and rotation.
Fig. 2 is an end view of the cluster drill.
Fig. 3 shows a pictoral representation of the horizontal reverse drilling system according to the present invention.
~t-~ 2001262 DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Fig. 1 a cross section of the modified cluster drill is shown and generally designated by Reference Numeral 1. The drill is comprised of a - cylindrical body barrel 2 having an end plug 3 at its forward or work producing end and a back head 4 at its rearward end. A plurality of downhole drills 5 are mounted in the barrel body 2 in a manner previously disclosed in U.S. Patent No. 4,729,439 which issued on March 8, 1988 and entitled Gang Drill Construction.
In general, each of the individual drills 5 are mounted in a bore 6 in the plug 3 and a tapered bore 7 in the back head 4. The tapered bore 7 cooperates with a taper 8 on each of the individual downhole drills 5. Each of the downhole drills 5 are retained in their respective tapered bores 7 by means of a cap nut 8. Pressure fluid is distributed to each of the circumferentially mounted downhole drills 5 by means of radial distribution bores 9.
In the prior art, cluster drill, the drill string is attached to the back head and supplies pressure fluid to the radial distribution bores. In the present invention the center drill is removed and replaced with a core rod 10. The core rod 10 -5a-Docket No. 0529-IR-RD
is provided with a central bore 11 which now supplies pressure fluid to the back head. The core rod 10 i~
provided with a thread 12 at its forward end 13 and is connected to the back head by a thread 14 or or 05 other convenient mQans.
Attached also to the back head i8 a socket flange 15 which permits attachment of an auger to the back heAd end o~ the drill. Mounted to each of the downhole drills 5, is a rock drill bit 16 (~hown in ~O phantom) whlch is impacted upon by the downhole drill and thereby fragment and remove rock p~rticles. Fig.
ROCK DRILLING METHOD AND APPARATUS
BACKGROUND OF THE lNv~ lON
During construction it i8 often de~irable to drill horizontal holes in rock under roadways and building foundations without disturbing those structures. Such horizontal holes may be used for 05 utility services, or drainage, or the like, and for this purpose it is desirable to have a straight hole economically drilled with a minimum of ground disturbance.
To accomplish such holes it is common to dig a shaft on either side of the structure and by means of auger in soft ground, or a rock drill in harder ground, drive the hole from shaft to shaft.
This is accomplished by utilizing conventional drilling techniques which push the auger or rock drill utilizing a rotary drill string. The auger or drill and trailing drill string is inserted in sections and driven from one of the shafts to the other.
Core drills have been developed for small diameter holes which are relatively effective in drilling accurate straight holes between two locations. However, effective core drilling is limited to holes of about 4 to 8 inches or smaller because the cores must be drilled in segments, 2S usually a maximum of twenty (20) ft. and removed.
~' ~OO~Z62 Docket No. 0529-IR-RD
In larger size holes the process would be slow and the cores become increasingly difficult to remove, particularly in hard rock. As a result, a common practice has developed in boring larger 05 diameter holes to first bore a cored hole and therea~ter force a series of rotary ring reamers through ths hole to increase the hole size to the diameter deslred.
Reaming is also time-consuming and in general produces a hole which i~ rough and/or cork screwed and as the size increase~ it becomes more difficult to maintain the progress without buckling the drill string creating the rotary drive and force on the ring cutters. An improvement to thls method lS involves the pulling of the ring cutters back through the hole but since this is a progressive stepwise operation the difficulty of the reamer walking about the hole diameter, although improved, still continues.
SUMMARY OF THE I~v~NllON
In the present invention a horizontal hole is accomplished by first sinking a shaft on either side of the hole to permit access. Next, a small diameter hole between the shafts of approximately 4"
is bored by core drilling. A drill string is next inserted in the hole. A modified clustered drill, generally of the type shown and described in U.S.
Patent No. 4,729,439, entitled "Gang Drill Construction" and assigned to Ingersoll-Rand Company, the assignee of the present invention, is ~o attached to the drill string. For purposes of this :
200~262 Docket No. 0529-IR-RD
invention the center drill is removed and replaced by a section of drill rod or center feed rod which supplies the gang drill with pressure fluid from its opposite end, that is the end that normally 05 contains th~ rock cutting bits. This permits the cluster drill to b~ rQversQ mounted to th~ drill string insertQd in th~ cored drill hole. The gang drill i8 then suppliQd with pres~urQ ~luid to operate the circumferentially mounted impact rock drills. The drill string is then rotated and withdrawn through the hole tailing and rotating the cluster drill. Pressure fluid and rock drill cuttings exit the large diameter hole in the conventional manner. As an added feature, sections of auger may be attached to the back of the gang drill to effect additional cleaning of the horizontal hole as the gang drill is drawn through the hole and rotated. This will reduce the overall air requirements necessary for cleaning the hole.
It is therefore an object of the present invention to provide a method and apparatus for the drilling of accurate large diameter horizontal holes in hard rock. It is an ob;ect of the invention to drill such holes in hard rock at high speed with efficiency and minimum air consumption.
It is yet a further object to accomplish the drilling of large diameter horizontal holes in hard rock by utilizing easily modified and available cluster drills, and simple rugged and reliable boring equipment of a small size compared to similar methods for similar size holes in hard rock.
These and other objects are obtained in an apparatus for drilling larger diameter holes in hard rock comprising: a cluster drill adapted for receiving pressure fluid and rotation from a drill string at its rock - 5 impacting end, the adaptation further comprising a means for receiving pressure fluid and connecting the cluster drill to a drill string provided at the impact end of said cluster drill on its centerline, a drill string connected to the means for connecting the drill string, the drill string further rotating and drawing the cluster drill into a drilled hole containing the drill string and enlarging the hole as it progresses.
It is a further object of the present invention to include auger means attached at the back end of the cluster drill for assisting in the removal of rock particles as the cluster drill progresses through the hole. The removal being accomplished by a combination of the auger trailing and rotating with the drill and exhaust pressure fluid - 20 thereby minimizing pressure fluid consumption in the removal of rock drill particles.
According to a still further broad aspect of the present invention, there is provided a gang drill for increasing the diameter of bored holes in hard rock. The drill comprises a plurality of individual percussion producing rock drills in a cylindrical drill body. The body has a rearward end and a forward end. The forward end has bit ends of the drills exposed for rock cutting arranged peripherally around the body. A drill string is connected at the centerline of the drills to the body at its forward end and at the centerline of the drills, for rotating and drawing the drills through a previously drilled bore hole to enlarge the previously drilled hole.
- 35 The body totally encloses the drills. The body is further provided with alignment means, securing means, and means ~a~
~- 2001262 for supplying pressure fluid for each of the drills. The pressure fluid enters the drills internally of the body and exits the drills externally to the body at its forward end, whereby the body forms a peripheral passage for exiting of S the rock cuttings and provides protection for individual drills. The means for supplying pressure fluid from the forward end of the body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby provides for reversal of the direction of drilling of the gang drill.
According to a still further broad aspect, the core rod is provided with a thread at its forward end for attachment to the drill string and is connected to the rearward end of the body by attachment means. The core rod is provided with a central passage formed therein for receiving pressure fluid from the forward end of the body.
According to a still further broad aspect, the gang drill has attached at its rearward end an auger means for assisting in the clearing of drilled debris with the auger means being rotated with the drill body.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. l shows a cross section view of a clustér drill modified according to the present invention for forward pressure fluid supply and rotation.
Fig. 2 is an end view of the cluster drill.
Fig. 3 shows a pictoral representation of the horizontal reverse drilling system according to the present invention.
~t-~ 2001262 DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Fig. 1 a cross section of the modified cluster drill is shown and generally designated by Reference Numeral 1. The drill is comprised of a - cylindrical body barrel 2 having an end plug 3 at its forward or work producing end and a back head 4 at its rearward end. A plurality of downhole drills 5 are mounted in the barrel body 2 in a manner previously disclosed in U.S. Patent No. 4,729,439 which issued on March 8, 1988 and entitled Gang Drill Construction.
In general, each of the individual drills 5 are mounted in a bore 6 in the plug 3 and a tapered bore 7 in the back head 4. The tapered bore 7 cooperates with a taper 8 on each of the individual downhole drills 5. Each of the downhole drills 5 are retained in their respective tapered bores 7 by means of a cap nut 8. Pressure fluid is distributed to each of the circumferentially mounted downhole drills 5 by means of radial distribution bores 9.
In the prior art, cluster drill, the drill string is attached to the back head and supplies pressure fluid to the radial distribution bores. In the present invention the center drill is removed and replaced with a core rod 10. The core rod 10 -5a-Docket No. 0529-IR-RD
is provided with a central bore 11 which now supplies pressure fluid to the back head. The core rod 10 i~
provided with a thread 12 at its forward end 13 and is connected to the back head by a thread 14 or or 05 other convenient mQans.
Attached also to the back head i8 a socket flange 15 which permits attachment of an auger to the back heAd end o~ the drill. Mounted to each of the downhole drills 5, is a rock drill bit 16 (~hown in ~O phantom) whlch is impacted upon by the downhole drill and thereby fragment and remove rock p~rticles. Fig.
2 showc the orientation of the downhole drills 5 about the central axis provided by the core rod 10.
It should be appreciated by one skilled in the art that pressure fluid (commonly compressed air) may be supplied via the core rod 10 through the radial distribution bores 9 in the back head 4 to each of the individual downhole drills 5. The pressure fluid creates a hammering action which is transmitted to the drill bits 16.
As shown in Fig. 3 the reverse cluster drill 1 is attached to a drill string 20 which is inserted in a previously bored core drill hole 21 of approximately the same diameter as the drill string.
The drill string 20 is in turn attached to a boring machine 26 of the type shown, for example, the boring machine supplied by NLC Company, Ltd. of Tokyo, Japan and distributed under the trade name Longyear Boring Machines. The boring machine 26 provides both rotation and tractive force to the drill string in operation to produce a bored hole 24.
Docket No. 0529-IR-RD
To produce a horizontal bore hole, shafts 25 and 25a are dug at either end of the intended bore hole. A boring ma~h~P 26 is next deployed in one of the shafts (for example 25) and mountQd on a 05 foundation 27. The boring machin~ i8 utilized to produce a drilled hole generally by a core drill in the 4 to 6 in. r~nge bQtween sha~ts 2S and 25A in a conventional manner utilizing drill string segments to advance the core drill.
On completion o~ the cored hole thQ core drill is removed and replaced with the cluster drill according to the present invention. The drill string is then withdrawn and rotated carrying with it the cluster drill 1 and an attached auger 30 which would be inserted in sections 30 following the cluster drill by means of a service crane 32 or the like.
Pressure fluid is supplied to the cluster drill 1 by an air compressor 31 (for example) through the boring machine and drill string to produce rock cutting impact action on the rock drill bits 16. As the drill is drawn through the hole it enlarges it to the desired diameter, D2.
The drill string in the smaller diameter Dl acts to centralize and stabilize the core drill as it is drawn into the larger diameter hole which it is producing. The drill string being in tension and acting as a centralizing stabilizer creates a straight true hole with the cluster drill.
Z001;~62 Docket No. 0529-IR-RD
PressurQ fluid exiting the cluster drill 1 and the action of the rotating auger 30 trailing the cluster drill and attached thereto by the threads of socket flange 15, cleans thQ debris 05 produced out of the large diameter hole and deposits it into shaft 25A where it may be removed. once the cluster drill reaches the shaft 25 it is removed and the segments of the auger are likewise removed completing the ~ob. Use of the auger greatly reduces the amount of air required for hole cleaning. However, air alone may be utilized to clean the hole.
The drilling system according to the present method has been utilized in boring holes o~ 500 to 800 millimeters (20 to 32 inches in diameter) in hard rock with hole lengths of 78 meters (230 ft.) with boring speeds substantially in excess of existing drilling methods. Longer and larger holes are well within the capability of this drilling system.
Having described my invention in terms of a preferred embodiment, I do not wish to be limited in the scope of my invention except as claimed.
It should be appreciated by one skilled in the art that pressure fluid (commonly compressed air) may be supplied via the core rod 10 through the radial distribution bores 9 in the back head 4 to each of the individual downhole drills 5. The pressure fluid creates a hammering action which is transmitted to the drill bits 16.
As shown in Fig. 3 the reverse cluster drill 1 is attached to a drill string 20 which is inserted in a previously bored core drill hole 21 of approximately the same diameter as the drill string.
The drill string 20 is in turn attached to a boring machine 26 of the type shown, for example, the boring machine supplied by NLC Company, Ltd. of Tokyo, Japan and distributed under the trade name Longyear Boring Machines. The boring machine 26 provides both rotation and tractive force to the drill string in operation to produce a bored hole 24.
Docket No. 0529-IR-RD
To produce a horizontal bore hole, shafts 25 and 25a are dug at either end of the intended bore hole. A boring ma~h~P 26 is next deployed in one of the shafts (for example 25) and mountQd on a 05 foundation 27. The boring machin~ i8 utilized to produce a drilled hole generally by a core drill in the 4 to 6 in. r~nge bQtween sha~ts 2S and 25A in a conventional manner utilizing drill string segments to advance the core drill.
On completion o~ the cored hole thQ core drill is removed and replaced with the cluster drill according to the present invention. The drill string is then withdrawn and rotated carrying with it the cluster drill 1 and an attached auger 30 which would be inserted in sections 30 following the cluster drill by means of a service crane 32 or the like.
Pressure fluid is supplied to the cluster drill 1 by an air compressor 31 (for example) through the boring machine and drill string to produce rock cutting impact action on the rock drill bits 16. As the drill is drawn through the hole it enlarges it to the desired diameter, D2.
The drill string in the smaller diameter Dl acts to centralize and stabilize the core drill as it is drawn into the larger diameter hole which it is producing. The drill string being in tension and acting as a centralizing stabilizer creates a straight true hole with the cluster drill.
Z001;~62 Docket No. 0529-IR-RD
PressurQ fluid exiting the cluster drill 1 and the action of the rotating auger 30 trailing the cluster drill and attached thereto by the threads of socket flange 15, cleans thQ debris 05 produced out of the large diameter hole and deposits it into shaft 25A where it may be removed. once the cluster drill reaches the shaft 25 it is removed and the segments of the auger are likewise removed completing the ~ob. Use of the auger greatly reduces the amount of air required for hole cleaning. However, air alone may be utilized to clean the hole.
The drilling system according to the present method has been utilized in boring holes o~ 500 to 800 millimeters (20 to 32 inches in diameter) in hard rock with hole lengths of 78 meters (230 ft.) with boring speeds substantially in excess of existing drilling methods. Longer and larger holes are well within the capability of this drilling system.
Having described my invention in terms of a preferred embodiment, I do not wish to be limited in the scope of my invention except as claimed.
Claims (11)
1. A gang drill for increasing the diameter of bored holes in hard rock comprising:
a plurality of individual percussion producing rock drills in a cylindrical drill body, said body having a rearward end and a forward end, said forward end having bit ends of said drills exposed for rock cutting arranged peripherally around said body and a drill string connected at the centerline of said drills to said body at its forward end for rotating and drawing said drills through a previously drilled bore hole to enlarge said previously drilled hole;
said body totally encloses said drills, said body being further provided with alignment means, securing means, and means for supplying pressure fluid for each of said drills, said pressure fluid entering said drills internally of said body and exiting said drills externally to said body at its forward end, whereby said body forms a peripheral passage for exiting of rock cuttings and provides protection for individual drills; and said means for supplying pressure fluid from said forward end of said body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby providing for reversal of the direction of drilling of said gang drill.
a plurality of individual percussion producing rock drills in a cylindrical drill body, said body having a rearward end and a forward end, said forward end having bit ends of said drills exposed for rock cutting arranged peripherally around said body and a drill string connected at the centerline of said drills to said body at its forward end for rotating and drawing said drills through a previously drilled bore hole to enlarge said previously drilled hole;
said body totally encloses said drills, said body being further provided with alignment means, securing means, and means for supplying pressure fluid for each of said drills, said pressure fluid entering said drills internally of said body and exiting said drills externally to said body at its forward end, whereby said body forms a peripheral passage for exiting of rock cuttings and provides protection for individual drills; and said means for supplying pressure fluid from said forward end of said body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby providing for reversal of the direction of drilling of said gang drill.
2. A gang drill according to claim 1, wherein said core rod is provided with a central passage formed therein for receiving pressure fluid from said forward end of said body.
3. A gang drill according to claim 1, wherein said center core rod replaces the center drill and said core rod is provided with a thread at its forward end for attachment to a drill string and is connected to the rearward end of said body by attachment means.
4. A gang drill according to claim 1, wherein said gang drill has attached at its rearward end an auger means for assisting in the clearing of drilled debris, said auger means being rotated with said drill body.
5. A gang drill according to claim 4, wherein said auger means is attached to said rearward end of said body by a socket flange adapted to be attached to an end plate in said body, said attachment means further serving as a sealing end cap for said end plate.
6. A gang drill for increasing the diameter of bored holes in hard rock comprising:
a plurality of individual percussion producing rock drills totally enclosed in a cylindrical drill body, said body having a rearward end and a forward end, said forward end having bit ends of said drills exposed for rock cutting arranged peripherally around said body and a drill string connected at the centerline of said drills to said body at its forward end for rotating and drawing said drills through a previously drilled bore hole to enlarge said previously drilled hole;
said body being further provided with alignment means, securing means, and means for supplying pressure fluid for each of said drills, said pressure fluid entering said drills internally of said body and exiting said drills externally to said body at its forward end, whereby said body forms a peripheral passage for exiting of rock cuttings and provides protection for said individual drills;
said means for supplying pressure fluid from said forward end of said body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby providing for reversal of the direction of drilling of said gang drill;
said core rod is provided with a thread at its forward end for attachment to the drill string and is connected to the rearward end of said body by attachment means; and said core rod is provided with a central passage formed therein for receiving pressure fluid from said forward end of said body.
a plurality of individual percussion producing rock drills totally enclosed in a cylindrical drill body, said body having a rearward end and a forward end, said forward end having bit ends of said drills exposed for rock cutting arranged peripherally around said body and a drill string connected at the centerline of said drills to said body at its forward end for rotating and drawing said drills through a previously drilled bore hole to enlarge said previously drilled hole;
said body being further provided with alignment means, securing means, and means for supplying pressure fluid for each of said drills, said pressure fluid entering said drills internally of said body and exiting said drills externally to said body at its forward end, whereby said body forms a peripheral passage for exiting of rock cuttings and provides protection for said individual drills;
said means for supplying pressure fluid from said forward end of said body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby providing for reversal of the direction of drilling of said gang drill;
said core rod is provided with a thread at its forward end for attachment to the drill string and is connected to the rearward end of said body by attachment means; and said core rod is provided with a central passage formed therein for receiving pressure fluid from said forward end of said body.
7. A gang drill according to claim 6, wherein said gang drill has attached at its rearward end an auger means for assisting in the clearing of drilled debris, said auger means being rotated with said drill body.
8. A gang drill according to claim 7, wherein said auger means is attached to said rearward end of said body by a socket flange adapted to be attached to an end plate in said body, said attachment means further serving as a sealing end cap for said end plate.
9. A gang drill for increasing the diameter of bored holes in hard rock comprising:
a plurality of individual percussion producing rock drills totally enclosed in a cylindrical drill body, said body having a rearward end and a forward end, said forward end having bit ends of said drills exposed for rock cutting arranged peripherally around said body and a drill string connected at the center line of said drills to said body at its forward end for rotating and drawing said drills through a previously drilled bore hole to enlarge said previously drilled hole;
said body being further provided with alignment means, securing means, and means for supplying pressure fluid for each of said drills, said pressure fluid entering said drills internally of said body and exiting said drills externally to said body at its forward end, whereby said body forms a peripheral passage for exiting of rock cuttings and provides protection for said individual drills;
said means for supplying pressure fluid from said forward end of said body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby providing for reversal of the direction of drilling of said gang drill;
said core is provided with a thread at its forward end for attachment to the drill string and is connected to the rearward end of said body by attachment means; and said gang drill has attached at its rearward end an auger means for assisting in the clearing of drilled debris, said auger means being rotated with said drill body.
a plurality of individual percussion producing rock drills totally enclosed in a cylindrical drill body, said body having a rearward end and a forward end, said forward end having bit ends of said drills exposed for rock cutting arranged peripherally around said body and a drill string connected at the center line of said drills to said body at its forward end for rotating and drawing said drills through a previously drilled bore hole to enlarge said previously drilled hole;
said body being further provided with alignment means, securing means, and means for supplying pressure fluid for each of said drills, said pressure fluid entering said drills internally of said body and exiting said drills externally to said body at its forward end, whereby said body forms a peripheral passage for exiting of rock cuttings and provides protection for said individual drills;
said means for supplying pressure fluid from said forward end of said body comprises a center core rod of approximately the same dimensions as an individual percussive drill allowing substitution for same and thereby providing for reversal of the direction of drilling of said gang drill;
said core is provided with a thread at its forward end for attachment to the drill string and is connected to the rearward end of said body by attachment means; and said gang drill has attached at its rearward end an auger means for assisting in the clearing of drilled debris, said auger means being rotated with said drill body.
10. A gang drill according to claim 9, wherein said auger means is attached to said rearward end of said body by a socket flange adapted to be attached to an end plate in said body, said attachment means further serving as a sealing end cap for said end plate.
11. A gang drill according to claim 10, wherein said core rod is provided with a central passage formed therein for receiving pressure fluid from said forward end of said body.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US26401688A | 1988-10-28 | 1988-10-28 | |
| US264,016 | 1988-10-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2001262A1 CA2001262A1 (en) | 1990-04-28 |
| CA2001262C true CA2001262C (en) | 1996-10-22 |
Family
ID=23004203
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2001262 Expired - Fee Related CA2001262C (en) | 1988-10-28 | 1989-10-23 | Rock drilling method and apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2001262C (en) |
-
1989
- 1989-10-23 CA CA 2001262 patent/CA2001262C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2001262A1 (en) | 1990-04-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |