U.S. patent application number 16/521196 was filed with the patent office on 2020-03-19 for percussive drill string assemblies and systems and methods of using same.
The applicant listed for this patent is BLY IP INC.. Invention is credited to CHRISTOPHER L. DRENTH, JEFFREY HOGAN, TUSHAR MATKAR.
Application Number | 20200087994 16/521196 |
Document ID | / |
Family ID | 69773839 |
Filed Date | 2020-03-19 |
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United States Patent
Application |
20200087994 |
Kind Code |
A1 |
HOGAN; JEFFREY ; et
al. |
March 19, 2020 |
Percussive Drill String Assemblies And Systems And Methods Of Using
Same
Abstract
A percussive drill string assembly including a drill bit and a
drill rod. The drill bit has a body having: a circumferential wall;
a crown extending distally from the circumferential wall; and a
threaded portion extending proximally from the circumferential
wall. The threaded portion has an outer surface that defines at
least one thread having a tapered thread profile. The drill rod has
a box end portion having an inner surface that defines: a
receptacle configured to receive the threaded portion of the bit;
and at least one thread having a tapered profile complementary to
the tapered thread profile of the threaded portion of the bit.
Inventors: |
HOGAN; JEFFREY; (Brampton,
CA) ; DRENTH; CHRISTOPHER L.; (Burlington, CA)
; MATKAR; TUSHAR; (Mississauga, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BLY IP INC. |
Salt Lake City |
UT |
US |
|
|
Family ID: |
69773839 |
Appl. No.: |
16/521196 |
Filed: |
July 24, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62732209 |
Sep 17, 2018 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 17/00 20130101;
E21B 1/00 20130101; E21B 10/003 20130101; E21B 10/36 20130101; E21B
17/0426 20130101; E21B 10/42 20130101; E21B 17/042 20130101; E21B
10/60 20130101 |
International
Class: |
E21B 17/042 20060101
E21B017/042; E21B 10/36 20060101 E21B010/36; E21B 10/42 20060101
E21B010/42 |
Claims
1. A single-rod percussive drill string assembly having a
longitudinal axis and comprising: a drill bit having: a body
having: a circumferential wall; and a crown extending distally from
the circumferential wall; and a threaded portion extending
proximally from the circumferential wall, wherein the threaded
portion has an outer surface that defines at least one thread
having a tapered thread profile; and a drill rod having: a box end
portion having an inner surface that defines: a receptacle
configured to receive the threaded portion of the bit; and at least
one thread having a tapered profile complementary to the tapered
thread profile of the threaded portion of the bit, wherein the
drill rod is the only drill rod of the percussive drill string
assembly.
2. The percussive drill string assembly of claim 1, wherein the box
end portion of the drill rod defines a distal end of the drill rod
and has an outer surface, wherein at least a portion of the outer
surface of the box end portion is inwardly tapered moving
proximally from the distal end.
3. The percussive drill string assembly of claim 1, wherein the
circumferential wall and the threaded portion of the drill bit
cooperate to define an interior space extending along the
longitudinal axis of the percussive drill string assembly.
4. The percussive drill string assembly of claim 3, wherein the
drill rod comprises a mid-body portion that extends proximally from
the box end portion, and wherein the mid-body portion has an inner
surface that cooperates with the circumferential wall and the
threaded portion of the drill bit to further define the interior
space.
5. The percussive drill string assembly of claim 3, wherein the
threaded portion of the drill bit defines a proximal end of the
drill bit and wherein the body of the drill bit defines a shoulder
that is configured to abut a distal end of the drill rod, and
wherein the drill bit comprises: a water slot defined by the
proximal end of the drill bit and extending radially from the
interior space to the outer surface of the threaded portion; and/or
a water slot defined by the shoulder and extending radially
outwardly to an exterior surface of the drill bit.
6. The percussive drill string assembly of claim 3, wherein the
crown of the body of the drill bit is a full-face crown.
7. The percussive drill string assembly of claim 6, wherein the
crown of the body of the drill bit defines a plurality of bores in
fluid communication with the interior space.
8. The percussive drill string assembly of claim 3, wherein the
circumferential wall of the body of the drill bit defines at least
one bore in fluid communication with the interior space.
9. The percussive drill string assembly of claim 1, wherein the
circumferential wall of the body of the drill bit has an outer
surface that defines at least one axial channel.
10. The percussive drill string assembly of claim 2, wherein the
outer surface of the box end portion of the drill rod defines a
plurality of axial slots.
11. The percussive drill string assembly of claim 10, wherein the
circumferential wall of the body of the drill bit has an outer
surface that defines at least one axial channel, and wherein at
least one axial slot of the plurality of axial slots is axially
aligned with a corresponding axial channel of the body of the drill
bit.
12. The percussive drill string assembly of claim 10, wherein the
axial slots are proximally tapered.
13. The percussive drill string assembly of claim 10, wherein the
box end portion of the drill rod has an axial length, and wherein
at least one axial slot of the plurality of axial slots has an
axial length that is greater than 60% of the axial length of the
box end portion.
14. The percussive drill string assembly of claim 4, wherein the
mid-body portion of the drill rod is welded to the box end portion
of the drill rod.
15. The percussive drill string assembly of claim 4, wherein the
mid-body and box end portions of the drill rod are forged as a
single piece.
16. The percussive drill string assembly of claim 1, wherein the
drill bit has a gauge diameter, wherein the circumferential wall
and the crown of the body of the drill bit have a combined axial
length, and wherein a ratio between the combined axial length of
the crown and the body of the drill bit and the gauge diameter of
the drill bit is less than 0.7.
17. The percussive drill string assembly of claim 1, wherein the
crown of the body of the drill bit has a staged profile.
18. The percussive drill string assembly of claim 10, wherein the
box end portion of the drill rod has an outer diameter that
circumscribes a cylinder, and wherein the plurality of axial slots
are inwardly recessed from the outer diameter and inwardly tapered
moving proximally from the distal end.
19. The percussive drill string assembly of claim 1, wherein the
drill rod comprises at least one back face defining a cutting
profile.
20. A drilling system comprising the percussive drill string
assembly of claim 1, wherein the drilling system is a single-pass
system that does not comprise an extension or an additional drill
rod.
21. A drilling method comprising: penetrating a formation using a
single-rod percussive drill string assembly having a longitudinal
axis and comprising: a drill bit having: a body having: a
circumferential wall; and a crown extending distally from the
circumferential wall; and a threaded portion extending proximally
from the circumferential wall, wherein the threaded portion has an
outer surface that defines at least one thread having a tapered
thread profile; and a drill rod having: a box end portion having an
inner surface that defines: a receptacle configured to receive the
threaded portion of the bit; and at least one thread having a
tapered profile complementary to the tapered thread profile of the
threaded portion of the bit wherein the drill rod is the only drill
rod of the percussive drill string assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of
U.S. Provisional Patent Application No. 62/732,209, filed Sep. 17,
2018, which is hereby incorporated by reference herein in its
entirety for all purposes.
FIELD
[0002] The disclosed invention relates to percussive drill string
assemblies, and, in particular, to single-rod percussive drill
string assemblies.
BACKGROUND
[0003] Conventionally, percussive bits are used to quickly
penetrate a variety of formations. In drifting, tunneling, and
bolting applications, a single-rod percussive drilling assembly can
be used. However, such single-rod assemblies are frequently
associated with inadequate advance and penetration rates, leading
to misalignment (incorrect hole initiation), deviation/divergence
of the hole (holes lacking desired straightness or smoothness),
drill rod tip-off or deflection (in response to collaring), and
deficiencies in hole-spotting. In order to avoid these issues,
there is a need for single-rod drilling assemblies that provide
increased advance and penetration rates to provide improved
strength, rod life, energy transmission, and flushing, thereby
resulting in more successful drilling operations.
SUMMARY
[0004] Described herein, in various aspects, is a percussive drill
string assembly having a longitudinal axis. The percussive drill
string assembly can include a drill bit and a drill rod. The drill
bit can have a body. The body of the drill bit can have: a
circumferential wall; a crown extending distally from the
circumferential wall; and a threaded portion extending proximally
from the circumferential wall. The threaded portion can have an
outer surface that defines at least one thread having a tapered
thread profile. The drill rod can have a box end portion having an
inner surface. The inner surface of the box end portion can define:
a receptacle configured to receive the threaded portion of the body
of the bit; and at least one thread having a tapered profile
complementary to the tapered thread profile of the threaded portion
of the body of the bit.
[0005] Also described are systems and methods of using the
disclosed drill string assemblies.
DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1A is a perspective view of an exemplary drill string
assembly as disclosed herein. FIG. 1B is a cross-sectional view of
the drill string assembly of FIG. 1A.
[0007] FIG. 2A is a perspective view of an exemplary drill string
assembly having a drill rod with axial slots as disclosed herein.
FIG. 2B is a perspective view of an exemplary drill string assembly
having a drill rod formed of round steel and defining axial slots
as disclosed herein.
[0008] FIG. 3 is a perspective view of an exemplary drill string
assembly having a crown with projecting buttons and a drill rod
with axial slots as disclosed herein.
[0009] FIG. 4A is a perspective view of an exemplary drill bit
having a body 22 and a proximal threaded portion as disclosed
herein. FIG. 4B is a perspective view of an exemplary drill bit
having a water slot in an alternative location.
[0010] FIG. 5A is a side elevational view of an exemplary drill bit
having a staged profile as disclosed herein. FIG. 5B is a top plan
view of the drill bit of FIG. 5A.
[0011] FIG. 6A is a perspective view of an exemplary drill rod
having a cylindrical outer diameter and tapered axial slots as
disclosed herein. FIG. 6B is a cross-sectional view of the drill
rod of FIG. 6A. FIG. 6C is a perspective view of another exemplary
drill rod having a cylindrical outer diameter and tapered axial
slots as disclosed herein.
[0012] FIG. 7 is a perspective view of an exemplary drill rod
having angled axial slots as disclosed herein.
[0013] FIG. 8A is a perspective view of a portion of a drill rod,
in accordance with embodiments disclosed herein, having cutting
removal features. FIG. 8B is side view of the portion of the drill
rod of FIG. 8A. FIG. 8C is a bottom view of the portion of the
drill rod of FIG. 8A. FIG. 8D is a detail view of the side view of
FIG. 8A.
DETAILED DESCRIPTION
[0014] The present invention now will be described more fully
hereinafter with reference to the accompanying drawings, in which
some, but not all embodiments of the invention are shown. Indeed,
this invention may be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
satisfy applicable legal requirements. Like numbers refer to like
elements throughout. It is to be understood that this invention is
not limited to the particular methodology and protocols described,
as such may vary. It is also to be understood that the terminology
used herein is for the purpose of describing particular embodiments
only, and is not intended to limit the scope of the present
invention.
[0015] Many modifications and other embodiments of the invention
set forth herein will come to mind to one skilled in the art to
which the invention pertains having the benefit of the teachings
presented in the foregoing description and the associated drawings.
Therefore, it is to be understood that the invention is not to be
limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended claims. Although specific terms
are employed herein, they are used in a generic and descriptive
sense only and not for purposes of limitation.
[0016] As used herein the singular forms "a", "an", and "the"
include plural referents unless the context clearly dictates
otherwise. For example, use of the term "a channel" can refer to
one or more of such channels.
[0017] All technical and scientific terms used herein have the same
meaning as commonly understood to one of ordinary skill in the art
to which this invention belongs unless clearly indicated
otherwise.
[0018] Ranges can be expressed herein as from "about" one
particular value, and/or to "about" another particular value. When
such a range is expressed, another aspect includes from the one
particular value and/or to the other particular value. Similarly,
when values are expressed as approximations, by use of the
antecedent "about," it will be understood that the particular value
forms another aspect. It will be further understood that the
endpoints of each of the ranges are significant both in relation to
the other endpoint, and independently of the other endpoint.
Optionally, in some aspects, when values are approximated by use of
the antecedent "about" or "substantially," it is contemplated that
values within up to 15%, up to 10%, or up to 5% (above or below) of
the particularly stated value or characteristic can be included
within the scope of those aspects.
[0019] As used herein, the terms "optional" or "optionally" mean
that the subsequently described event or circumstance may or may
not occur, and that the description includes instances where said
event or circumstance occurs and instances where it does not.
[0020] The word "or" as used herein means any one member of a
particular list and also includes any combination of members of
that list.
[0021] As used herein, the term "proximal" refers to a direction
toward the surface of a formation (where a drill rig can be
located), whereas the term "distal" refers to a direction toward
the bottom or end of a drill hole, moving away from the surface of
the formation. When the terms "proximal" and "distal" are used to
describe system components, it is expected that during normal use
of those components, the "proximal" components will be positioned
proximally (closer to the surface of the formation) relative to the
"distal" components and the "distal" components will be positioned
distally (closer to the bottom of a drill hole) relative to the
"proximal" components.
[0022] As used herein, the term "[metal]-based alloy" (where
[metal] is any metal) means commercially pure [metal] in addition
to metal alloys wherein the weight percentage of [metal] in the
alloy is greater than the weight percentage of any other component
of the alloy. Where two or more metals are listed in this manner,
the weight percentage of the listed metals in combination is
greater than the weight percentage of any other component of the
alloy.
[0023] As used herein, the term "tungsten carbide" means any
material composition that contains chemical compounds of tungsten
and carbon in any stoichiometric or non-stoichiometric ratio or
proportion, such as, for example, WC, W.sub.2C, and combinations of
WC and W.sub.2C. Tungsten carbide includes any morphological form
of this material, for example, cast tungsten carbide, sintered
tungsten carbide, monocrystalline tungsten carbide, and
macrocrystalline tungsten carbide.
[0024] As used herein, the term "wear-resistant" refers to a
drilling tool that is not designed to erode or degrade to expose
cutting material imbedded or otherwise positioned within the
drilling tool. Thus, wear-resistant tools are distinguishable
from--and operate in a fundamentally different way
than--impregnated drilling tools that are designed to wear away to
continuously expose cutting media within the drilling tools.
[0025] The following description supplies specific details in order
to provide a thorough understanding. Nevertheless, the skilled
artisan would understand that the apparatus and associated methods
of using the apparatus can be implemented and used without
employing these specific details. Indeed, the apparatus and
associated methods can be placed into practice by modifying the
illustrated apparatus and associated methods and can be used in
conjunction with any other apparatus and techniques conventionally
used in the industry.
[0026] Disclosed herein are drill string assemblies and associated
systems and methods. It is contemplated that the disclosed drill
string assemblies can provide one or more improvements or
advantages in comparison to existing tunneling drill string
assemblies, leading to increases in rod life and straighter holes.
Conventionally, rod tip-off is a major problem for tunneling rods.
Often, the rods are (incorrectly) used for scaling purposes,
leading to dragging of the bit along rock as a hammering operation
continues and resulting in undesirable loading problems that
exacerbate the problem of rod failure. As further disclosed herein,
it is contemplated that the disclosed drill string assemblies can
provide better flushing and tip-off resistance in comparison to
conventional tunneling rod assemblies. It is further contemplated
that the disclosed drill string assemblies can reduce or eliminate
the misuse of rods for scaling purposes.
[0027] Disclosed herein, in various aspects and with reference to
FIGS. 1A-7 is a drill string assembly 10 having a longitudinal axis
12. In exemplary aspects, the drill string assembly 10 can have a
drill bit 20 and a drill rod 50. The drill bit 20 can have a body
22, which can include a circumferential (annular) wall 30 and a
crown 24 extending distally from the circumferential wall. The
drill bit 20 can further comprise a threaded portion 40 extending
proximally from the circumferential wall 30. In further aspects,
the threaded portion 40 can have an outer surface that defines at
least one thread 42 having a tapered thread profile. In additional
aspects, the drill rod 50 can have a box end portion 52 having an
inner surface 56. In these aspects, the inner surface 56 of the box
end portion 52 can define a receptacle 58 configured to receive the
threaded portion 42 of the bit 20. In still further aspects, the
inner surface 56 of the box end portion 52 can define at least one
thread 60 having a tapered profile complementary to the tapered
thread profile of the threaded portion 42 of the bit 20. In
exemplary aspects, it is contemplated that the tapered thread
profile of the threaded portion 42 of the bit can have a taper
ranging from about 1 degree to about 10 degrees relative to the
longitudinal axis 12.
[0028] Optionally, it is contemplated that the drill bit 20 can be
a wear-resistant drill bit. Optionally, in exemplary aspects, the
drill bit 20 can be a percussive drill bit, such as a button drill
bit, a blade drill bit, or a down-the-hole (DTH) hammer bit. In
exemplary aspects, the drill bit 20 can be a button drill bit
comprising buttons 25, such as, for example and without limitation,
a rotary drag bit, a bi-cone bit, or a tri-cone bit. Such buttons
can be secured to the cutting face of the bit using conventional
methods. Optionally, such buttons can comprise carbide (e.g.,
tungsten carbide) and/or polycrystalline diamond (PCD).
Alternatively, it is contemplated that buttons 25 can be integrally
formed with the matrix that forms the bit 20. Although depicted as
a drill bit in the Figures, it is contemplated that other
wear-resistant drilling tools, such as hole reamers, back reamers,
hole openers, and drill string stabilizers, can be used in place of
the disclosed drill bit, in combination with the drill rod 50.
[0029] In exemplary aspects, the body 22 of the drill bit 20 can be
an infiltrated body comprising a matrix and a binder. In these
aspects, the matrix can comprise a hard particulate material and a
plurality of abrasive particles dispersed throughout the hard
particulate material. It is contemplated that the binder can secure
the hard particulate material and the abrasive particles together.
In exemplary aspects, the plurality of abrasive particles can
comprise a plurality of diamond particles. However, it is
contemplated that any conventional abrasive cutting media can be
used.
[0030] In exemplary aspects, the box end portion 52 of the drill
rod 50 can define a distal end 54 of the drill rod and have an
outer surface 62. Optionally, in these aspects, it is contemplated
that at least a portion of the outer surface 62 of the box end
portion 52 can be inwardly tapered (toward the longitudinal axis
12) moving proximally from the distal end 54. It is contemplated
that the combination of a drill bit with a tapered thread and a
drill rod having a box end portion with a tapered outer diameter
can permit use of a standard (non-cylindrical) mid-body design in
the drill rod. It is further contemplated that this combination can
provide for more efficient evacuation of cuttings and more drilling
productivity in comparison to the use of straight couplings/rods.
In exemplary aspects, at least a portion of the outer surface 62 of
the box end portion 52 can be inwardly tapered at an angle ranging
from about 2 degrees to about 10 degrees. Optionally, as shown in
FIG. 1A, the entire outer surface 62 can have a consistent taper.
Alternatively, in further aspects and as shown in FIGS. 6A-6C, the
box end portion 52 of the drill rod 50 can have an outer diameter
that circumscribes a cylinder. In these aspects, the box end
portion 52 can comprise a plurality of axial slots 64 (further
described below) that are inwardly recessed from the outer diameter
and inwardly tapered moving proximally from the distal end 54. It
is contemplated that these axial slots can be inwardly tapered at
an angle ranging from about 2 degrees to about 10 degrees.
Optionally, in some aspects, at least one axial slot 64
(optionally, each axial slot 64) of the plurality of axial slots
can have a straight profile as shown in FIGS. 6A and 6C.
Alternatively, in other aspects, and as shown in FIG. 7, the outer
diameter of the box end portion need not circumscribe a cylinder.
In these aspects, a plurality of axial slots 64 can be inwardly
recessed from the outer diameter and inwardly tapered moving
proximally from the distal end 54. As shown, it is contemplated
that at least one axial slot 64 (optionally, each axial slot) of
the plurality of axial slots can have a spiral or helical
profile.
[0031] Optionally, in exemplary aspects, the plurality of axial
slots 64 can be equally or substantially equally circumferentially
spaced about the outer surface 62 of the box end portion 52. In one
aspect, it is contemplated that the plurality of axial slots 64 can
optionally be equally or substantially equally sized. Optionally,
in further exemplary aspects, it is contemplated that the plurality
of axial slots 64 can comprise from 2 to 16 axial slots or, more
practically, from 2 to 6 axial slots, including, for example, 3, 4,
or 5 axial slots.
[0032] In further aspects, the circumferential wall 30 and the
threaded portion 42 of the drill bit 20 can cooperate to define an
interior space 35 extending along the longitudinal axis 12 of the
drill string assembly (e.g., percussive drill string assembly) 10.
Optionally, in additional aspects and as shown in FIGS. 1A-2B, the
drill rod 50 can comprise a mid-body portion 66 that extends
proximally from the box end portion 52. In these aspects, the
mid-body portion 66 can have an inner surface 68 that cooperates
with the circumferential wall 30 and the threaded portion 42 of the
body 22 of the drill bit 20 to further define the interior space
35. In use, the interior space 35 can be configured to receive
water or other drilling fluid during use of the drill bit 20. In
one aspect, the water or other drilling fluid can be supplied to
the interior space 35 at a desired pressure.
[0033] Optionally, it is contemplated that the mid-body portion 66
of the drill rod 50 can be welded to the box end portion 52 of the
drill rod 50. Alternatively, in other optional aspects, it is
contemplated that the mid-body and box end portions 66, 52 of the
drill rod 50 can be formed as a single piece using forging in
accordance with conventional single-piece forging methods.
[0034] In additional exemplary aspects, and with reference to FIGS.
1B and 4A-5B, the threaded portion 42 of the drill bit 20 can
define a proximal end 44 of the drill bit. In these aspects, the
proximal end 44 of the drill bit 20 can comprise a water slot 46a
(optionally, a plurality of water slots) extending radially from
the interior space 35 to the outer surface of the threaded portion
42. Additionally, or alternatively, as shown in FIG. 4B, the body
22 of the drill bit 20 can have a distal end that defines a
shoulder 27 that is configured to abut a distal end of the drill
rod 50, with the shoulder defining a water slot 46b (optionally, a
plurality of water slots) to provide a radial flow pathway between
the drill bit 20 and the drill rod 50. In use, as shown in FIGS.
4A-4B, it is contemplated that the water slot 46a can allow for the
outward flow of a small volume of water (or other drilling fluid)
from the interior space to cool and clean the threads of the bit
20.
[0035] Optionally, in exemplary aspects, the crown 24 of the body
22 of the drill bit 20 can be a full-face crown. In these aspects,
the crown 24 of the body 22 of the drill bit 20 can define a
plurality of bores 28 in fluid communication with the interior
space 35. Additionally, or alternatively, in further aspects, the
circumferential wall 30 of the body 22 of the drill bit 20 can
define at least one bore 36 in fluid communication with the
interior space 35.
[0036] In exemplary aspects, it is contemplated that the plurality
of bores 36 can be configured to direct water (or other drilling
fluid) directly (or substantially directly) to the distal (cutting)
face 26 from the interior space 25. It is further contemplated that
the direct supply of pressurized water (or other drilling fluid) to
the cutting face 26 can increase flow velocity across the cutting
face, thereby permitting more rapid removal of cuttings and
significantly increasing the convective cooling of the cutting
face. It is further contemplated that the plurality of bores 36 can
reduce the contact area of the cutting face 26 relative to
conventional drill bits, thereby improving the penetration rate of
the drill bit 10. It is still further contemplated that the
plurality of bores 36 can permit novel distribution of water (or
other drilling fluid) relative to the cutting face 26, thereby
improving the wear resistance of the drill bit 10. It is still
further contemplated that the plurality of bores 36 can provide
flexibility in the distribution of water (or other drilling fluid)
such that the center port of conventional drill bits is unnecessary
(and can be eliminated from the drill bit). Optionally, in some
aspects, it is contemplated that the cutting face 26 can have a
convex profile. In other aspects, it is contemplated that the
cutting face 26 can optionally have a concave profile.
[0037] In exemplary aspects, the plurality of bores 28 can
optionally be equally (or substantially equally) distributed about
the face 26. Optionally, in some aspects, the plurality of bores 28
can be randomly spaced from a center point of the drill bit 20. In
other aspects, the plurality of bores can optionally be uniformly
(or substantially uniformly) spaced from the center point of the
drill bit 20. In these aspects, it is contemplated that at least
two concentric rows of bores can be provided, with the bores in
each respective row being uniformly (or substantially uniformly)
spaced from the center point of the drill bit 20. More generally,
it is contemplated that the plurality of bores 28, 36 can be
provided in any selected configuration. It is further contemplated
that the plurality of bores 28, 36 can be distributed so as to
optimize the wear characteristics of the drill bit 20 for a
particular application.
[0038] It is contemplated that the each bore 28, 36 of the
plurality of bores can be provided in a selected shape. In
exemplary aspects, the plurality of bores 28, 36 can have a
cylindrical shape (with a circular cross-sectional profile) or a
substantially cylindrical shape (with a substantially circular
cross-sectional profile). However, it is contemplated that the
plurality of bores 28, 36 can have any shape, including, for
example and without limitation, a conical or substantially conical
(tapered) shape (with a circular or substantially circular
cross-sectional profile), a shape having a rectangular or
substantially rectangular cross-sectional profile, a shape having a
square or substantially square cross-sectional profile, an S-shape,
and the like.
[0039] Optionally, in further exemplary aspects, it is contemplated
that an inner surface of the bit 20 (that defines the interior
space 35) can define at least one flute extending parallel or
substantially parallel to the longitudinal axis 12. In these
aspects, each flute of the at least one flute can optionally
correspond to a rounded groove extending radially from the inner
surface of the circumferential wall toward the outer surface 32 of
the circumferential wall. It is contemplated that the at least one
flute can optionally be positioned in fluid communication with at
least one bore 28, 36 of the body 22 of the bit 20.
[0040] Optionally, in further exemplary aspects, and as shown in
FIGS. 1A-5B, the circumferential wall 30 of the body 22 of the
drill bit 20 can have an outer surface 32 that defines at least one
axial channel 34 (optionally, a plurality of axial channels) that
extends axially relative to the longitudinal axis 12 and is
inwardly recessed from the outer surface 32 (toward the
longitudinal axis). In use, the at least one axial channel 34 can
be configured to permit delivery of cuttings from the cutting face
of the bit to the annulus between the outer diameter of the drill
bit and the drill hole.
[0041] Optionally, in exemplary aspects, the plurality of axial
channels 34 can be equally or substantially equally
circumferentially spaced about the outer surface 32 of the body 22
of the drill bit 20. In one aspect, it is contemplated that the
plurality of axial channels 34 can optionally be equally or
substantially equally sized. Optionally, in further exemplary
aspects, it is contemplated that the plurality of axial channels 34
can comprise from 2 to 16 axial channels or, more practically, from
2 to 6 axial channels, including, for example, 2, 3, 4, or 5 axial
channels.
[0042] In further exemplary aspects, the circumferential wall 30 of
the body 22 of the drill bit 20 can completely circumferentially
enclose the interior space 35. In still further exemplary aspects,
the circumferential wall 30 does not comprise a waterway extending
radially between the outer surface of the circumferential wall and
the interior space.
[0043] Additionally, or alternatively, in further exemplary
aspects, the outer surface 62 of the box end portion 52 of the
drill rod 50 can define a plurality of axial slots 64. Optionally,
in these aspects, when the outer surface 32 of the circumferential
wall 30 of the body 22 of the drill bit 20 defines at least one
axial channel 34 as shown in FIGS. 2A-3, it is contemplated that at
least one axial slot 64 of the plurality of axial slots can be
axially aligned with a corresponding axial channel of the body of
the drill bit. Optionally, it is contemplated that the axial slots
64 can be proximally tapered (with a width that decreases moving in
a proximal direction) as shown in FIGS. 2A-2B. Alternatively, it is
contemplated that the axial slots 64 can be distally tapered (with
a width that decreases moving in a distal direction) as shown in
FIG. 3.
[0044] In exemplary aspects, the box end portion 52 of the drill
rod 50 can have an axial length. In these aspects, at least one
axial slot (optionally, each axial slot) 64 of the plurality of
axial slots can have an axial length that is greater than 60
percent of the axial length of the box end portion 52. It is
further contemplated that at least one axial slot (optionally, each
axial slot) 64 of the plurality of axial slots can have an axial
length that ranges from about 60 to about 90 percent, from about 70
to about 90 percent, from about 70 to about 80 percent, or from
about 80 to about 90 percent of the axial length of the box end
portion 52.
[0045] In further exemplary aspects, the drill bit 20 can have a
gauge diameter, and the circumferential wall 30 and the crown 24 of
the body 22 of the drill bit can have a combined axial length
(measured relative to the longitudinal axis 12). In these aspects,
it is contemplated that a ratio between the combined axial length
of the crown 24 and the circumferential wall 30 of the body 22 of
the drill bit and the gauge diameter of the drill bit can be less
than 0.7 or can range from about 0.5 to about 0.8 or from about 0.6
to about 0.7. Optionally, in some exemplary aspects, the combined
axial length of the circumferential wall and the crown of the body
of the drill bit can be less than 2 inches. In operation, by
minimizing the amount of exposed bit (positioned outside the
receptacle of the drill rod), cantilever stresses are minimized,
thereby avoiding or reducing the risk of rod failure at the
connection with the bit.
[0046] Optionally, in exemplary aspects, and as shown in FIGS.
5A-5B, the crown 24 of the body 22 of the drill bit 20 can have a
staged profile. As shown, it is contemplated that the staged
profile can include a center platform 38 that projects upwardly
from the remainder (i.e., a base portion) of the body 22 of the bit
20. In these aspects, it is contemplated that the outer surface 32
of the base portion of the body 22 of the bit can further comprise
at least one flute 37 (optionally, a plurality of flutes) that are
positioned in fluid communication with (optionally, in contact
with) a corresponding channel 34. Optionally, at least one flute 37
(optionally, each flute) can be angularly oriented relative to the
longitudinal axis 12 of the drill string assembly 10. Additionally,
or alternatively, in further aspects, at least one flute 37
(optionally, each flute) can be angularly oriented relative to
(i.e., not parallel or aligned with) the channel 34 that is in
fluid communication with the flute 37. As shown in FIGS. 5A-5B, it
is contemplated that the center platform 38 can define the crown 24
of the bit 20. It is further contemplated that buttons 25 can be
secured to (or integrally formed with) the center platform and
extend from the crown 24. As shown in FIGS. 5A-5B, it is still
further contemplated that buttons 25 can be secured to (or
integrally formed with) the outer surface of the base portion of
the body of the bit (from which the center platform 38 projects).
Optionally, it is further contemplated that the center platform 38
can define at least one bore extending to the face 26 of the crown
24 and in fluid communication with the interior space 35 as further
disclosed herein. Optionally, it is further contemplated that the
base portion of the body 22 of the bit can define a bore 36 that is
in fluid communication with the interior space 35 as further
disclosed herein. In exemplary aspects, the total length of the
body 22 of the staged drill bit (including the center platform) as
shown in FIGS. 5A-5B can range from about 5 inches to about 6.5
inches. Optionally, in these aspects, it is contemplated that the
maximum outer diameter of the body 22 of the staged drill bit
(i.e., measured at the base portion) can range from about 3.5 to
about 6 inches.
[0047] In exemplary aspects, it is contemplated that the drill
string assembly 10 can be provided as a portion of a drilling
system. Optionally, in these aspects, the drilling system can
comprise a drill or drill rig as is known in the art. In use, it is
contemplated that a drill can be operatively secured or coupled to
the disclosed drill string assembly 10 such that the drill can
effect movement of the drill string assembly. Optionally, in
exemplary aspects, the drilling system can comprise a production
drill, such as a hydraulic production drill as is known in the art.
An example of a suitable hydraulic production drill is the
STOPEMASTER.TM. hydraulic production drill manufactured by Boart
Longyear (Salt Lake City, Utah).
[0048] In further exemplary aspects, the drilling system can be a
single-pass system that does not comprise an extension or an
additional drill rod. That is, in these aspects, it is contemplated
that the drilling system can comprise only a single drill rod (that
is a component of the drill string assembly 10).
[0049] Referring to FIGS. 8A-8D, in some embodiments, the drill rod
50 can comprise a back face 80 that is provided with a cutting
profile 82 that comprises at least one cutting edge 84. The cutting
edge 84 can be a surface oriented so that vectors extending
perpendicularly to the surface's face extend at least partially in
a direction of travel of the cutting edge 84 as it rotates about
the drill rod's longitudinal axis 12 (FIG. 1A). In use, it is
contemplated that the drill string can rotate counter-clockwise.
Accordingly, the at least one cutting edge 84 can be disposed to
engage cuttings as the drill rod 50 rotates counter-clockwise. In
exemplary aspects, the at least one cutting edge 84 defined on the
back face 80 can have a substantially saw-tooth cutting profile. It
is contemplated that the at least one cutting edge 84 of the back
face 80 can be configured to cut and/or agitate cuttings, thereby
promoting removal of the drill rod 50 from the hole and increasing
the productivity of drilling operations. In use, it is contemplated
that the cutting profile 82 can cooperate with flutes 37 to provide
increased efficiency in chip evacuation.
[0050] In exemplary aspects, the cutting profile 82 can comprise a
plurality of back cutting teeth 86. The teeth 86 can be
circumferentially spaced about the back face 80. Optionally, it is
contemplated that the plurality of teeth 86 can be substantially
equally circumferentially spaced about the back face 80. In an
additional aspect, it is contemplated that each tooth 86 of the
plurality of teeth can define a respective cutting edge 84 of the
back face 80. In one exemplary aspect, the plurality of back
cutting teeth 86 can comprise five back cutting teeth. In other
aspects, the cutting profile 82 can comprise a plurality of
recessed portions 88 positioned between adjacent teeth 86 of the
plurality of back cutting teeth. For example, in one aspect, when
the plurality of back cutting teeth 86 comprises five teeth, it is
contemplated that the plurality of recessed portions 88 can
comprise five recessed portions. In further aspects, the recessed
portions 88 can be defined by corresponding sloped portions 83 of
the cutting profile 82. In these aspects, as shown in FIGS. 8A-8D,
it is contemplated that the sloped portions 83 of the cutting
profile 82 can be oriented at a selected angle 89a relative to a
plane 85 positioned perpendicular to the longitudinal axis 12 (FIG.
1A) of the drill rod 50. It is further contemplated that the
selected angle 89a can range from about 5.degree. to about
45.degree.. In one exemplary aspect, it is contemplated that the
selected angle 89a can range from about 10.degree. to about
30.degree.. In another exemplary aspect, it is contemplated that
the selected angle 89a can range from about 15.degree. to about
20.degree..
[0051] Still referring to FIGS. 8A-8D, the back surface 80 can be a
step that, at least in certain portions, defines a shoulder surface
that is perpendicular to the longitudinal axis. The sloped portions
83 can transition to a surface of increasing concavity in a
clockwise direction 90 that ultimately defines the cutting edge 84.
Thus, the cutting edge 84 can engage the cuttings as the bit
rotates in the counterclockwise direction 91. The sloped portions
83 can have an end 92 that is opposite the back cutting teeth 86.
The back cutting teeth 86 can extend to a proximal edge 93 (moving
away from the cutting face of the bit) that is on the same
transverse plane as the end 92 of the sloped portions 83.
[0052] Methods of using the described percussive drill string
assembly 10 are also disclosed. Optionally, it is contemplated that
the drill string assembly can be used in a horizontal or
near-horizontal drilling operation, such as in conventional
tunneling or drifting processes. It is further contemplated that
the drill string assembly can be used in a bolting process (e.g., a
rock bolting process for stabilizing a rock excavation) as is known
in the art.
Exemplary Materials
[0053] The binder materials disclosed herein can include, for
example, cobalt-based, iron-based, nickel-based, silver-based, iron
and nickel-based, cobalt and nickel-based, iron and cobalt-based,
aluminum-based, copper-based, magnesium-based, molybdenum based,
and titanium-based alloys. The alloying elements can include, but
are not limited to, one or more of the following
elements--manganese (Mn), nickel (Ni), silver (Ag), tin (Sn), zinc
(Zn), silicon (Si), molybdenum (Mo), tungsten (W), boron (B) and
phosphorous (P). The binder material can also be selected from
commercially pure elements such as cobalt, aluminum, silver,
copper, magnesium, titanium, iron, and nickel. By way of example
and not limitation, the binder composite material can include
carbon steel, alloy steel, stainless steel, tool steel, Hadfield
manganese steel, nickel or cobalt superalloy material, and low
thermal expansion iron or nickel based alloys.
[0054] The abrasive particles of the matrix compositions disclosed
herein can comprise diamond, synthetic diamond, metal or semi-metal
carbides, nitrides, oxides, or borides. For example, and without
limitation, the abrasive particles can comprise diamond or ceramic
materials such as carbides, nitrides, oxides, and borides
(including boron carbide (B.sub.4C)) and combinations of them, such
as carbonitrides. More specifically, the abrasive particles can
comprise carbides and borides made from elements such as W, Ti, Mo,
Nb, V, Hf, Ta, Cr, Zr, Al, and Si. By way of example and without
limitation, materials that may be used to form abrasive particles
include tungsten carbide (WC, W.sub.2C), titanium carbide (TiC),
tantalum carbide (TaC), titanium diboride (TiB.sub.2), chromium
carbides, titanium nitride (TiN), vanadium carbide (VC), aluminium
oxide (Al.sub.2O.sub.3), aluminium nitride (AlN), boron nitride
(BN), and silicon carbide (SiC). Furthermore, combinations of
different abrasive particles may be used to tailor the physical
properties and characteristics of the matrix material. The abrasive
particles may be formed using techniques known to those of ordinary
skill in the art. Most suitable materials for abrasive particles
are commercially available and the formation of the remainder is
within the ability of one of ordinary skill in the art.
[0055] In one example, and not meant to be limiting, the hard
particulate material of the matrix can comprise a tungsten-based
alloy. In a further example, and not meant to be limiting, the hard
particulate material of the matrix can comprise a tungsten
carbide-based alloy. However, it is contemplated that other
conventional hard particulate materials can be used.
Exemplary Aspects
[0056] In view of the described devices, systems, and methods and
variations thereof, herein below are described certain more
particularly described aspects of the invention. These particularly
recited aspects should not however be interpreted to have any
limiting effect on any different claims containing different or
more general teachings described herein, or that the "particular"
aspects are somehow limited in some way other than the inherent
meanings of the language literally used therein.
[0057] Aspect 1: A percussive drill string assembly having a
longitudinal axis and comprising: a drill bit having: a body
having: a circumferential wall; and a crown extending distally from
the circumferential wall; and a threaded portion extending
proximally from the circumferential wall, wherein the threaded
portion has an outer surface that defines at least one thread
having a tapered thread profile; and a drill rod having: a box end
portion having an inner surface that defines: a receptacle
configured to receive the threaded portion of the bit; and at least
one thread having a tapered profile complementary to the tapered
thread profile of the threaded portion of the bit.
[0058] Aspect 2: The percussive drill string assembly of aspect 1,
wherein the box end portion of the drill rod defines a distal end
of the drill rod and has an outer surface, wherein at least a
portion of the outer surface of the box end portion is inwardly
tapered moving proximally from the distal end.
[0059] Aspect 3: The percussive drill string assembly of aspect 1
or aspect 2, wherein the circumferential wall and the threaded
portion of the drill bit cooperate to define an interior space
extending along the longitudinal axis of the percussive drill
string assembly.
[0060] Aspect 4: The percussive drill string assembly of aspect 3,
wherein the drill rod comprises a mid-body portion that extends
proximally from the box end portion, and wherein the mid-body
portion has an inner surface that cooperates with the
circumferential wall and the threaded portion of the drill bit to
further define the interior space.
[0061] Aspect 5: The percussive drill string assembly of aspect 3
or aspect 4, wherein the threaded portion of the drill bit defines
a proximal end of the drill bit and wherein the body of the drill
bit defines a shoulder that is configured to abut a distal end of
the drill rod, and wherein the drill bit comprises: a water slot
defined by the proximal end of the drill bit and extending radially
from the interior space to the outer surface of the threaded
portion; and/or a water slot defined by the shoulder and extending
radially outwardly to an exterior surface of the drill bit.
[0062] Aspect 6: The percussive drill string assembly of any one of
aspects 3-5, wherein the crown of the body of the drill bit is a
full-face crown.
[0063] Aspect 7: The percussive drill string assembly of aspect 6,
wherein the crown of the body of the drill bit defines a plurality
of bores in fluid communication with the interior space.
[0064] Aspect 8: The percussive drill string assembly of any one of
aspects 3-7, wherein the circumferential wall of the body of the
drill bit defines at least one bore in fluid communication with the
interior space.
[0065] Aspect 9: The percussive drill string assembly of any one of
the preceding aspects, wherein the circumferential wall of the body
of the drill bit has an outer surface that defines at least one
axial channel.
[0066] Aspect 10: The percussive drill string assembly of any one
of aspects 2-9, wherein the outer surface of the box end portion of
the drill rod defines a plurality of axial slots.
[0067] Aspect 11: The percussive drill string assembly of aspect
10, wherein the circumferential wall of the body of the drill bit
has an outer surface that defines at least one axial channel, and
wherein at least one axial slot of the plurality of axial slots is
axially aligned with a corresponding axial channel of the body of
the drill bit.
[0068] Aspect 12: The percussive drill string assembly of aspect 10
or aspect 11, wherein the axial slots are proximally tapered.
[0069] Aspect 13: The percussive drill string assembly of any one
of aspects 10-12, wherein the box end portion of the drill rod has
an axial length, and wherein at least one axial slot of the
plurality of axial slots has an axial length that is greater than
60% of the axial length of the box end portion.
[0070] Aspect 14: The percussive drill string assembly of any one
of aspects 4-13, wherein the mid-body portion of the drill rod is
welded to the box end portion of the drill rod.
[0071] Aspect 15: The percussive drill string assembly of any one
of aspects 4-14, wherein the mid-body and box end portions of the
drill rod are forged as a single piece.
[0072] Aspect 16: The percussive drill string assembly of any one
of the preceding aspects, wherein the drill bit has a gauge
diameter, wherein the circumferential wall and the crown of the
body of the drill bit have a combined axial length, and wherein a
ratio between the combined axial length of the crown and the body
of the drill bit and the gauge diameter of the drill bit is less
than 0.7.
[0073] Aspect 17: The percussive drill string assembly of any one
of the preceding aspects, wherein the crown of the body of the
drill bit has a staged profile.
[0074] Aspect 18: The percussive drill string assembly of any one
of aspects 10-17, wherein the box end portion of the drill rod has
an outer diameter that circumscribes a cylinder, and wherein the
plurality of axial slots that are inwardly recessed from the outer
diameter and inwardly tapered moving proximally from the distal
end.
[0075] Aspect 19: A drilling system comprising the percussive drill
string assembly of any one of the preceding aspects.
[0076] Aspect 20: The drilling system of aspect 19, wherein the
drilling system is a single-pass system that does not comprise an
extension or an additional drill rod.
[0077] Aspect 21: A method of using the percussive drill string
assembly of any one of aspects 1-18.
[0078] Aspect 22: The method of aspect 21, wherein the percussive
drill string assembly is used in a tunneling or bolting
process.
[0079] Aspect 23: The percussive drill string assembly of any one
of aspects 1-18, wherein the drill rod comprises at least one back
face defining a cutting profile.
[0080] All publications and patent applications mentioned in the
specification are indicative of the level of those skilled in the
art to which this invention pertains. All publications and patent
applications are herein incorporated by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by
reference.
[0081] Although the foregoing invention has been described in some
detail by way of illustration and example for purposes of clarity
of understanding, certain changes and modifications may be
practiced within the scope of the appended claims.
* * * * *