The invention relates to drilling, and more particularly, to subs for blast hole drilling and other mining operations.
Known drilling machines include a frame supported for movement over the ground, and a tower mounted on the frame for movement between a generally horizontal stowed position, and a vertical or angled operating position. A deck is supported by the frame and has a generally horizontal upper surface with an opening through which a drill rod is extendable. A rotary head is movable along the tower and engageable with the drill rod to move the drill rod vertically and to rotate the drill rod.
The rotary head urges the drill rod downwardly to penetrate the ground and to create a drilled hole. Known drilling machines are capable of drilling to depths greater than the height of the tower by connecting multiple drill rods together to create a drill string that is longer than the height of the tower. This is accomplished by drilling a first drill rod into the ground until the rotary head is completely lowered. Next, the rotary head is disconnected from first drill rod and raised to the top of the tower such that a second, upper drill rod can be connected to the rotary head. The second drill rod is then threaded to the first, lower drill rod, and the second drill rod can then be drilled into the ground. Additional drill rods can be added to the drill string in a similar manner until the hole is drilled to the desired depth.
With known drilling methods, the drilling depth that is reachable without requiring the use of multiple drill rods is generally limited by the height of the tower. That is, a single drill rod can only be drilled to a depth corresponding to the distance that is traveled by the rotary head in moving from the top of the tower to the bottom of the tower. If a hole having a depth greater than the travel distance of the rotary head is required, additional drill rods must be utilized. The process of coupling and decoupling multiple drill rods to one another in order to drill to a desired depth adds significant time, cost, and complication to a drilling operation. Furthermore, known methods of coupling and decoupling drill rods, including impact breakout systems and non-impact breakout systems, are often inconsistent and can damage the drill rods and the drilling machine.
The present invention provides a telescoping sub that is coupleable to a drill rod for mining operations and the like. The telescoping sub includes a rotor portion coupleable to the drilling machine, and a stator portion coupleable to the drill rod. The rotor portion is slideably coupled to the stator portion and is moveable between an extended position and a retracted position to increase the depth to which the hole can be drilled.
In some embodiments, a bottom sub and a seal guide are coupled to a stator housing to define a chamber. A rotor shaft is received by the chamber and a plurality of lock plates are coupled to the stator housing and positioned in an annular space defined between the rotor shaft and the stator housing. A first detent assembly is positioned within the chamber adjacent the bottom sub, and a second detent assembly is positioned within the chamber adjacent the seal guide. A rotor dog is coupled to an end of the rotor shaft and engages the lock plates when the rotor portion is in the extended and retracted positions. The first and second detent assemblies engage the rotor dog in the retracted and extended positions, respectively, and provide detent rotational engagement between the rotor portion and the stator portion.
The present invention also provides a method for drilling a hole in the ground with such a telescoping sub. The drill rod is rotated in a first direction, and urged into the ground to a first depth. Downward movement is stopped, and the rotor portion is rotated in a second direction and moved vertically with respect to the stator portion to the extended position. While in the extended position, the telescoping sub is again rotated in the first direction and urged into the ground to a second depth that is greater than the first depth.
Other features of the invention will become apparent to those skilled in the art upon review of the following detailed description, and drawings.
a is a perspective view illustrating a bottom sub of the telescoping sub shown in
b is a side view illustrating the bottom sub shown in
c is a section view taken along line A-A of
a is a perspective view illustrating a stator housing of the telescoping sub shown in
b is a side view of the stator housing shown in
c is an end view of the stator housing showin in
a is a perspective view illustrating a seal guide of the telescoping sub shown in
b is a side view of the seal guide shown in
c is an end view of the seal guide shown in
a is a perspective view illustrating a rotor shaft of the telescoping sub shown in
b is a side view of the rotor shaft shown in
c is an end view of the rotor shaft shown in
a is a perspective view illustrating a bushing of the telescoping sub shown in
b is a side view of the bushing shown in
c is an end view of the bushing shown in
b is a side view of the bushing shown in
c is an end view of the bushing shown in
a is a perspective view illustrating a lock plate of the telescoping sub shown in
b is a side view of the lock plate shown in
c is an end view of the lock plate shovn in
d is another end view of the lock plate shown in
a is an exploded view illustrating a detent assembly of the telescoping sub shown in
b is an end view of the detent housing shown in
c is a side view of the detent housing shown in
a is a perspective view illustrating a kelly bushing of the telescoping sub shown in
b is a side view of the kelly bushing shown in
Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.
Referring also to
With reference now to
The telescoping sub 50 also includes a generally tubular stator housing 74 (
The telescoping sub 50 further includes a generally tubular seal guide 82 (
In addition, the telescoping sub 50 includes a rotor shaft 94 (
The second end 102 has a reduced diameter with respect to the first end 98 and is configured to be at least partially received by the seal guide 82 and the stator housing 74. The second end 102 includes an annular end surface 114 having formed therein a plurality of angularly spaced apart and axially inwardly extending threaded bores 118. The threaded bores 118 are substantially equally spaced along a bolt circle, and an axially extending annular projection 122 extends away from the annular end surface 114 and is radially inwardly spaced with respect to the threaded bores 118. A channel 126 extends through the rotor shaft 94 from the annular projection 122 to the externally threaded projection 106.
A bushing 130 (
Referring also to
Each lock plate 138 includes an arcuate cross section (see
The telescoping sub 50 includes a pair of detent couplings 166 (
The locking pins 174 have a length that is longer than the detent housing 168 such that when the telescoping sub 50 is assembled, the locking pins 174 extend through the holes 170 of the detent housing 168 and into the blind bores 164 of the upper or lower engagement tabs 162, 158. The locking pins 174 non-rotatably fix the detent couplings 166 to the lock plates 138 and the stator housing 74. The detent pins 172 include rounded ends 180 and are biased by the wave spring washer 178 such that the rounded ends 180 selectively extend into the detent recesses 144 defined by the drive dogs 142, thereby providing detent engagement between the detent couplings 166 and the rotor dog 134 during rotation of the rotor shaft 94 with respect to the stator housing 74.
Referring also to
As mentioned above, a conventional drill rod can be coupled to the telescoping sub 50, thereby forming a drill rod assembly. The length of the drill rod is preferably selected such that the combined length of the drill rod, any additional subs, and the telescoping sub 50 in the retracted position substantially corresponds to the distance traveled by the rotary head 36 in moving between the raised and lowered positions. With the sub 50 in the retracted position, the rotary head 36 is operated to rotate the telescoping sub 50 in a first (e.g. clockwise) direction, and the feed cable system 44 is operated to urge the rotary head 36 downwardly, thereby drilling a hole in the ground 16. The drilling operation continues until the flats 70 on the bottom sub 54 are substantially aligned with the clamping mechanism on the deck 17. Rotation and downward movement of the rotary head 36 is halted and the clamping mechanism engages the flats 70 such that the bottom sub 54 is held substantially fixed. The rotary head 36 is then operated to rotate the rotor shaft 94 in a second, opposite direction (e.g. counter-clockwise) to overcome the detent coupling 166 and to disengage the drive dogs 142 from the lower engagement tabs 158 (see
When the hole has been drilled to the desired depth, the rotary head 36 and feed cable system 44 are operated to withdraw the telescoping sub 50 from the hole. When the flats 70 of the bottom sub 54 are aligned with the deck 17, the clamping mechanism engages the bottom sub 54 and the rotary head 36 and feed cable system 44 are operated to return the sub 50 to the retracted position. The remaining length of the drill rod assembly is then withdrawn from the hole in the conventional manner.
More specifically, the telescoping sub 50′ includes a stator housing 74′ to which a bottom sub (similar to the bottom sub 54) can be coupled. The stator housing 74′ receives a rotor shaft 94′ having a plurality of axially extending grooves 186 defined along an outer surface thereof. Although not illustrated in
The kelly bushing 184 is generally annular and includes an inner surface 188 that defines a plurality of axially extending output grooves 190, and an outer surface 192 that defines a plurality of axially extending input grooves 194. The kelly bushing 184 is configured to receive the rotor shaft 94′ and a plurality of drive pins 196 (only one drive pin 196 is illustrated in
Operation of the telescoping sub 50′ and movement of the telescoping sub 50′ between the retracted and the extended positions is substantially the same as that described above with respect to the telescoping sub 50. With the telescoping sub 50′ in the retracted position, the rotary table is operated to rotate the telescoping sub 50′ and the drill rod assembly, while a feed system (which may or may not be similar to the feed cable system 44) urges the drill rod assembly downwardly to drill the hole. When a first depth is reached, the rotary table and feed system are operated to move the telescoping sub 50′ to the extended position and the drilling operation is then resumed until the hole is drilled to the desired or maximum depth.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US04/06674 | 3/4/2004 | WO | 7/12/2007 |