U.S. patent application number 10/709653 was filed with the patent office on 2005-11-24 for self-aligning insert for drill bits.
Invention is credited to Schutt, Gordon, Tucker, Joseph.
Application Number | 20050257963 10/709653 |
Document ID | / |
Family ID | 35374094 |
Filed Date | 2005-11-24 |
United States Patent
Application |
20050257963 |
Kind Code |
A1 |
Tucker, Joseph ; et
al. |
November 24, 2005 |
Self-Aligning Insert for Drill Bits
Abstract
The present invention is generally directed to various
embodiments of a self-aligning insert for use with roller cone
drill bits. In one illustrative embodiment, the insert comprises a
generally cylindrical body, a cutting surface, a bottom surface, a
tapered surface adjacent the cylindrical body, and a generally
cylindrical section positioned between the bottom surface and the
tapered surface. The inserts of the present invention may be
installed in a roller cone of a roller cone drill bit.
Inventors: |
Tucker, Joseph; (Seabrook,
TX) ; Schutt, Gordon; (Houston, TX) |
Correspondence
Address: |
JEFFREY E. DALY
GRANT PRIDECO, L.P.
400 N. SAM HOUSTON PARKWAY EAST
SUITE 900
HOUSTON
TX
77060
US
|
Family ID: |
35374094 |
Appl. No.: |
10/709653 |
Filed: |
May 20, 2004 |
Current U.S.
Class: |
175/432 |
Current CPC
Class: |
E21B 10/16 20130101;
E21B 10/56 20130101 |
Class at
Publication: |
175/432 |
International
Class: |
E21B 010/36 |
Claims
1. A rolling cutter insert, comprising: a generally cylindrical
body, a cutting surface, and a bottom surface; a tapered surface
adjacent said generally cylindrical body; and a generally
cylindrical section positioned between said bottom surface and said
tapered surface.
2. The device of claim 1, further comprising a radiused corner
region adjacent said bottom surface, said radiused corner region
being positioned between said bottom surface and said generally
cylindrical section.
3. The device of claim 2, wherein said generally cylindrical
section is adjacent said radiused corner region.
4. The device of claim 1, wherein said generally cylindrical body
has a diameter that is greater than a diameter of said generally
cylindrical section.
5. The device of claim 1, further comprising a radiused region
positioned between said tapered surface and said generally
cylindrical section.
6. The device of claim 2, wherein said radiused corner region
defines a transition between said bottom surface and said generally
cylindrical section.
7. The device of claim 5, wherein said radiused region defines a
transition between said cylindrical section and said tapered
surface.
8. The device of claim 1, wherein said tapered surface is formed at
an angle of approximately 15 degrees relative to a longitudinal
axis of said generally cylindrical body.
9. The device of claim 1, wherein said radiused corner region has a
radius of approximately 0.020 inches.
10. The device of claim 5, wherein said radiused region has a
radius of approximately 0.20 inches.
11. The device of claim 1, wherein said generally cylindrical
section has an axial length of approximately 0.020 inches.
12. The device of claim 1, further comprising a roller cutter drill
bit comprised of at least one roller cone, wherein said roller
cutter insert is press fit into an opening formed in said roller
cone.
13. A rolling cutter insert, comprising: a generally cylindrical
body, a cutting surface, and a bottom surface; a tapered surface
adjacent said generally cylindrical body; a radiused corner region
adjacent said bottom surface; and a generally cylindrical section
positioned between said radiused corner region and said tapered
surface, wherein said radiused corner region defines a transition
between said bottom surface and said generally cylindrical
section.
14. The device of claim 13, wherein said generally cylindrical body
has a diameter that is greater than a diameter of said generally
cylindrical section.
15. The device of claim 13, further comprising a radiused region
positioned between said tapered surface and said generally
cylindrical region.
16. The device of claim 15, wherein said radiused region defines a
transition between said generally cylindrical section and said
tapered surface.
17. The device of claim 13, wherein said tapered surface is formed
at an angle of approximately 15 degrees relative to a longitudinal
axis of said generally cylindrical body.
18. The device of claim 13, further comprising a roller cutter
drill bit comprised of at least one roller cone, wherein said
roller cutter insert is press fit into an opening formed in said
roller cone.
19. A rolling cutter insert, comprising: a generally cylindrical
body, a cutting surface, and a bottom surface; a tapered surface
adjacent said generally cylindrical body; a radiused corner region
adjacent said bottom surface; a generally cylindrical section
positioned between said radiused corner region and said tapered
surface, wherein said radiused corner region defines a transition
between said bottom surface and said generally cylindrical section;
and a radiused region positioned between said tapered surface and
said generally cylindrical section, wherein said radiused region
defines a transition between said generally cylindrical section and
said tapered surface.
20. The device of claim 19, wherein said generally cylindrical body
has a diameter that is greater than a diameter of said generally
cylindrical section.
21. The device of claim 19, wherein said tapered surface is formed
at an angle of approximately 15 degrees relative to a longitudinal
axis of said generally cylindrical body.
22. The device of claim 19, further comprising a roller cutter
drill bit comprised of at least one roller cone, wherein said
roller cutter insert is press fit into an opening formed in said
roller cone.
23. A rolling cutter insert, comprising: a generally cylindrical
body, a cutting surface, and a bottom surface; a tapered surface
adjacent said generally cylindrical body; and a region of material
positioned between said bottom surface and said tapered surface,
said region of material positioned outside of a volume defined, at
least in part, by an intersection of a linear extension of said
tapered surface with said bottom surface.
24. The device of claim 23, further comprising a generally
cylindrical section positioned between said tapered surface and
said bottom surface, wherein at least a portion of said generally
cylindrical section defines at least a part of said region of
material.
25. The device of claim 24, further comprising a radiused corner
region between said generally cylindrical section and said bottom
surface.
26. The device of claim 25, wherein at least a portion of said
radiused corner region defines at least part of said region of
material.
27. The device of claim 25, wherein said generally cylindrical
section is adjacent said radiused corner region.
28. The device of claim 23, further comprising a radiused corner
region positioned adjacent said bottom surface, wherein at least a
portion of said radiused corner region defines at least part of
said region of material.
29. The device of claim 24, wherein said generally cylindrical body
has a diameter that is greater than a diameter of said generally
cylindrical section.
30. The device of claim 24, further comprising a radiused region
positioned between said tapered surface and said generally
cylindrical section.
31. The device of claim 25, wherein said radiused corner region
defines a transition between said bottom surface and said generally
cylindrical section.
32. The device of claim 30, wherein said radiused region defines a
transition between said generally cylindrical section and said
tapered surface.
33. The device of claim 23, wherein said tapered surface is formed
at an angle of approximately 15 degrees relative to a longitudinal
axis of said generally cylindrical body.
34. A rolling cutter insert, comprising: a generally cylindrical
body; a cutting surface; and a bottom portion extending from said
generally cylindrical body, said bottom portion comprising a bottom
surface and a tapered surface, said tapered surface being formed
adjacent said generally cylindrical body, wherein said bottom
portion is configured such that there is a region of material
positioned between said bottom surface and said tapered surface,
said region of material being positioned outside of a volume
defined, at least in part, by an intersection of a linear extension
of said tapered surface with said bottom surface.
35. The device of claim 34, further comprising a generally
cylindrical section positioned between said tapered surface and
said bottom surface, wherein at least a portion of said generally
cylindrical section defines at least a part of said region of
material.
36. The device of claim 35, further comprising a radiused corner
region between said generally cylindrical section and said bottom
surface.
37. The device of claim 36, wherein at least a portion of said
radiused corner region defines at least part of said region of
material.
38. The device of claim 36, wherein said generally cylindrical
section is adjacent said radiused corner region.
39. The device of claim 34, further comprising a radiused corner
region positioned adjacent said bottom surface, wherein at least a
portion of said radiused corner region defines at least part of
said region of material.
40. The device of claim 35, wherein said generally cylindrical body
has a diameter that is greater than a diameter of said generally
cylindrical section.
41. The device of claim 35, further comprising a radiused region
positioned between said tapered surface and said generally
cylindrical section.
42. The device of claim 36, wherein said radiused corner region
defines a transition between said bottom surface and said generally
cylindrical section.
43. The device of claim 41, wherein said radiused region defines a
transition between said generally cylindrical section and said
tapered surface.
44. The device of claim 34, wherein said tapered surface is formed
at an angle of approximately 15 degrees relative to a longitudinal
axis of said generally cylindrical body.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is generally directed to the field of
roller cone drill bits, and, more particularly, to a self-aligning
insert that may be used on a roller cone drill bit.
[0003] 2. Description of the Related Art
[0004] Oil and gas wells are formed by a rotary drilling process.
To that end, a drill bit is mounted on the end of a drill string
which may be very long, e.g., several thousand feet. At the
surface, a rotary drive mechanism turns the drill string and the
attached drill bit at the bottom of the hole. In some cases, a
downhole motor may provide the desired rotation to the drill bit.
During drilling operations, a drilling fluid (so-called drilling
mud) is pumped through the drill string and back up-hole by pumps
located on the surface. The purpose of the drilling fluid is to,
among other things, remove the earthen cuttings resulting from the
drilling process.
[0005] FIG. 1 depicts an exemplary rolling cutter rock drill bit 10
within which the present invention may be used. A "rolling cutter
rock drill bit" is also commonly called a rock bit, a rolling
cutter drill bit or an oilfield drill bit. The illustrated bit 10
includes a body 12 having three legs 14. In this type of bit, as is
known in the art, a cantilevered bearing spindle (not shown in FIG.
1) formed on each leg 14 extends inwardly and downwardly and is
capable of carrying a rotatably mounted rolling cutter 18. A
plurality of bearings are arranged on the bearing spindle to
support the rotatably mounted rolling cutter 18. Attached to each
illustrated rolling cutter 18 are hard, wear-resistant cutting
inserts 20, which are capable of engaging the earth to effect a
drilling action and cause rotation of the rolling cutter 18.
[0006] The inserts 20 on the rolling cutters 18 crush and cut the
rock as drilling operations are performed with the necessary force
being supplied by the "weight-on-bit"(WOB) which presses down on
the drill bit 10 and by the torque applied by the rotary drive
mechanism. During the drilling process, very large and non-constant
stresses and forces may be applied to the inserts 20, the rolling
cutters 18, and the drill bit 10 itself. The cutting inserts 20
typically have a generally cylindrical shape and a generally
circular cross-sectional configuration. The cutting inserts 20 are
received by sockets, or insert holes, drilled into the rolling
cutter 18, perpendicular to the surface of the rolling cutter 18
body. A plurality of insert holes drilled along the same radius of
a band to form a row of insert holes on that band. The cutting
inserts 20 are held in place in the sockets by an interference
fit.
[0007] To provide an interference fit between the cutting insert 20
and the socket, the socket is formed with a diameter slightly
smaller than that of the cylindrical body of the cutting insert 20.
The cutting insert 20 is then pressed into the socket and retained
by the contact force between the socket wall and the outer wall
surface of the cylindrical body of the cutting insert. Because the
diameter of the insert 20 is greater than the inside diameter of
the socket, and because of the hardness of the cutting insert
material, e.g., tungsten carbide, the installation procedure can be
difficult and can damage the socket. A damaged socket can reduce
the contact force between the cutting insert 20 and the socket
wall. If the socket becomes sufficiently damaged during
installation, the cutting insert 20 can dislodge from the socket
during drilling operations. Additionally, a damaged socket can also
allow the cutting insert 20 to rotate in the socket during
drilling, which can decrease the cutting effectiveness of the
cutting insert 20.
[0008] As indicated above, inserts 20 are typically pressed into an
opening or socket formed in the body of the rolling cutter 18. The
installation process typically involves the use of very powerful
presses to force the insert 20 into the opening or socket formed in
the rolling cutter 18 body. By way of example, FIG. 3 depicts an
illustrative insert 20 comprised of a generally cylindrical body
61, a cutting surface 62, a bottom surface 63, a tapered surface
64, and a rounded or radiused corner 65 that provides the
transition between the tapered surface 64 and the bottom surface
63. Typically, the tapered surface 64 is formed at an angle of
approximately 15 degrees relative to the centerline 67 of the
cylindrical body 61 of the insert 20.
[0009] Using existing inserts, such as the insert 20 depicted in
FIG. 3, it is frequently difficult and time-consuming to insure
that the insert 20 is properly aligned with an opening 70 (see FIG.
4) formed in the rolling cutter body 18a prior to pressing the
insert 20 into the opening 70. As depicted in FIG. 4, the insert 20
may be misaligned, e.g., tilted, relative to the centerline 72 of
the opening 70. Depending upon the particular application, such
misalignment could cause many severe problems as it relates to the
installation of the insert 20 in the opening 70. For example,
depending upon the magnitude of the misalignment, the insert 20
could cut or damage the entrance of the opening 70 thereby
lessening the effectiveness of the interference fit between the
insert 20 and the opening 70. Accordingly, manufacturers have
resorted to a variety of techniques and methods in an attempt to
overcome or reduce the problems associated with the misalignment of
the insert 20 with the opening 70 formed in the cutter body 18a. To
that end, in some applications, a guide device (not shown) would be
positioned around the opening 70 to assist in aligning the insert
20 with the centerline 72 of the opening 70. However, in some
applications, there is insufficient room for the use of such guide
devices. In other cases, manual efforts were used in an attempt to
properly align the insert 20 with the opening 70 prior to
performing the pressing operations. Such activities included
grasping the insert 20 with a tong-like tool in an effort to
maintain the proper alignment of the insert 20 as the pressing
operation is begun. Such manual activities relating to the
alignment of the insert 20 with the opening 70 are time-consuming,
expensive, and may lead to inconsistent results as related to the
quality of the installation of the insert 20 in the opening 70.
[0010] The present invention is directed to devices and methods
that may solve, or at least reduce, some or all of the
aforementioned problems.
SUMMARY OF INVENTION
[0011] The present invention is generally directed to various
embodiments of a self-aligning insert for use with roller cone
drill bits. In one illustrative embodiment, the insert comprises a
generally cylindrical body, a cutting surface, a bottom surface, a
tapered surface adjacent the generally cylindrical body, and a
generally cylindrical section positioned between the bottom surface
and the tapered surface. Cutter inserts in accordance with the
present invention may be installed in the roller cones of roller
cone drill bits.
[0012] In another illustrative embodiment, the insert comprises a
generally cylindrical body, a cutting surface, a bottom surface, a
tapered surface adjacent the generally cylindrical body, a radiused
corner region adjacent the bottom surface, and a generally
cylindrical section positioned between the radiused corner region
and the tapered surface, wherein the radiused corner region defines
a transition between the bottom surface and the generally
cylindrical section.
[0013] In yet another illustrative embodiment, the insert comprises
a generally cylindrical body, a cutting surface, a bottom surface,
a tapered surface adjacent the generally cylindrical body, a
radiused corner region adjacent the bottom surface, a generally
cylindrical section positioned between the radiused corner region
and the tapered surface, wherein the radiused corner region defines
a transition between the bottom surface and the generally
cylindrical section, and a radiused region positioned between the
tapered surface and the generally cylindrical section, wherein the
radiused region defines a transition between the generally
cylindrical section and the tapered surface.
[0014] In a further illustrative embodiment, the insert comprises a
generally cylindrical body, a cutting surface, a bottom surface, a
tapered surface adjacent the generally cylindrical body, and a
region of material positioned between the bottom surface and the
tapered surface, the region of material positioned outside of a
volume defined, at least in part, by an intersection of a linear
extension of the tapered surface with the bottom surface.
[0015] In yet a further illustrative embodiment, the insert
comprises a generally cylindrical body, a cutting surface, and a
bottom portion extending from the generally cylindrical body, the
bottom portion comprising a bottom surface and a tapered surface,
the tapered surface being formed adjacent the generally cylindrical
body, wherein the bottom portion is configured such that there is a
region of material positioned between the bottom surface and the
tapered surface, the region of material being positioned outside of
a volume defined, at least in part, by an intersection of a linear
extension of the tapered surface with the bottom surface.
BRIEF DESCRIPTION OF DRAWINGS
[0016] The invention may be understood by reference to the
following description taken in conjunction with the accompanying
drawings, in which like reference numerals identify like
elements.
[0017] FIG. 1 is a perspective view of a prior art rolling cutter
drill bit.
[0018] FIG. 2 is a cross-sectional view of a prior art rolling
cutter drill bit.
[0019] FIG. 3 is a side view of an illustrative prior art insert
that may be installed in the rolling cutter drill bit depicted in
FIG. 1.
[0020] FIG. 4 depicts an illustrative misalignment between the
insert depicted in FIG. 3 when it is installed in an opening formed
in one of the rolling cutters of the drill bit depicted in FIG.
1.
[0021] FIG. 5 is a side view of an illustrative insert in
accordance with one illustrative embodiment of the present
invention.
[0022] FIG. 6 is an enlarged view of a portion of one illustrative
embodiment of an insert in accordance with the present
invention.
[0023] FIG. 7 is a side view that compares one illustrative
embodiment of the present invention with a prior art insert.
[0024] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof have been shown
by way of example in the drawings and are herein described in
detail. It should be understood, however, that the description
herein of specific embodiments is not intended to limit the
invention to the particular forms disclosed, but on the contrary,
the intention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the invention
as defined by the appended claims.
DETAILED DESCRIPTION
[0025] Illustrative embodiments of the invention are described
below. In the interest of clarity, not all features of an actual
implementation are described in this specification. It will, of
course, be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developers" specific goals, such as compliance with
system-related and business-related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time-consuming, but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure.
[0026] The present invention will now be described with reference
to the attached drawings which are included to describe and explain
illustrative examples of the present invention. The relative size
of the various features shown in the drawings may not be to scale,
as some features may be exaggerated for purposes of explanation.
The words and phrases used herein should be understood and
interpreted to have a meaning consistent with the understanding of
those words and phrases by those skilled in the relevant art. No
special definition of a term or phrase, i.e., a definition that is
different from the ordinary and customary meaning as understood by
those skilled in the art, is intended to be implied by consistent
usage of the term or phrase herein. To the extent that a term or
phrase is intended to have a special meaning, i.e., a meaning other
than that understood by skilled artisans, such a special definition
will be expressly set forth in the specification in a definitional
manner that directly and unequivocally provides the special
definition for the term or phrase.
[0027] The present invention will now be described with reference
to FIGS. 5 and 6. FIG. 5 is a side view of an illustrative insert
100 in accordance with one embodiment of the present invention.
FIG. 6 is an enlarged view of a portion of the insert 100 as a
portion of the insert 100 is positioned in an opening 110 formed in
an illustrative cutter body 120. As indicated in FIG. 5, the insert
100 is generally comprised of a generally cylindrical body or shank
101, a bottom surface 102, and a cutting surface 103. The insert
100 further comprises a radiused corner region 104, a generally
cylindrical section 105, a radiused region 106 and a tapered
surface 107. In a general sense, the insert 100 may comprise a
cutting surface 103, a generally cylindrical body 101, and a lower
portion 108, i.e., the portions of the insert extending below the
generally cylindrical body 101. The generally cylindrical section
105 may be a true cylindrical section or it may have a very slight
taper, e.g., up to approximately 5 degrees or so, for manufacturing
reasons. For example, such a slightly tapered generally cylindrical
section 105 may be employed such that a punch used to manufacture
the insert 100 can be removed without damaging the insert 100. As
used herein, the phrase "generally cylindrical section" shall be
understood to include a true cylindrical section as well as a
slightly tapered section that is tapered for manufacturing reasons.
As will be recognized by those skilled in the art after a complete
reading of the present application, the present invention has broad
applicability and thus should not be considered as limited to the
embodiments specifically disclosed herein. For example, the cutting
surface 103 of the insert 100 may be of any desired shape or
configuration. Typically, the insert 100 is comprised of a tungsten
carbide material, although it may be made from other materials if
desired.
[0028] FIG. 6 is an enlarged view of a portion of the insert 100 as
it is positioned in an opening 110 in a cutter body 120. In this
illustrative example, the opening 110 has chamfered corners 111
adjacent the bottom of the opening 110. In one illustrative
embodiment, the bottom surface 102 of the insert 100 extends beyond
the generally cylindrical body or shank 101 by a depth 112 of
approximately 0.050 inches. Of course, the depth 112 of the bottom
portion 108 may vary depending upon the particular application. In
one illustrative embodiment, the tapered surface 107 is formed at
an angle 113 of approximately 15 degrees relative to a centerline
109 of the insert 100. In one illustrative embodiment, the radiused
region 106 provides a transition from the tapered surface 107 to
the generally cylindrical surface 105. In one particularly
illustrative embodiment, the radiused region 106 has a radius of
approximately 0.020 inches and an included angle of approximately
15 degrees. Similarly, in one embodiment, the radiused corner 104
provides a transition between the bottom surface 102 of the insert
100 and the generally cylindrical section 105. If a taper is
provided on the generally cylindrical section 105, it will be less
than the tapered angle 113 of the tapered surface 107. In one
particularly illustrative embodiment, the radiused corner region
104 has a radius of approximately 0.020 inches and an included
angle of approximately 90 degrees.
[0029] As described above, the insert 100 will be press-fit into
the opening 110 to secure the insert 100 therein. Accordingly, the
body 101 of the insert 100 has a diameter 101D that is somewhat
greater than the diameter of the generally circular opening 110. In
one illustrative embodiment, the diameter 101D of the insert body
101 may be approximately 0.316 inches, whereas the opening 110 may
have a diameter of approximately 0.312 inches. Of course, the
physical size of the insert body 101 as well as the opening 110 may
vary depending upon the particular application. In the illustrative
embodiment depicted herein, the generally cylindrical section 105
has a diameter 105D of approximately 0.307 inches resulting in a
clearance 114 of approximately 0.009 inches. Of course, the
clearance 114 may vary depending upon the particular application.
In some illustrative embodiments, the clearance 114 may be
approximately 0.007-0.012 inches. The axial length of the generally
cylindrical section 105 may also vary depending upon the
application and the depth 112 of the lower portion 108. In one
illustrative embodiment, the generally cylindrical section 105 has
an axial length, i.e., a length approximately parallel to the
centerline 109 of the insert 100, of approximately 0.020 inches. In
some applications, the axial length may vary from approximately
0.010 inches to 0.050 inches. The opening 110 may be formed in any
region of a cutter body, and it may have a generally circular
configuration. In some cases, the opening 110 may be formed
directly in the curved surface 110A of a roller cone body. In other
cases, the surface 110A depicted in FIG. 6 may be a flat surface.
That is, the present invention may be employed in applications
where a generally flat surface is provided around the perimeter of
the opening 110. Such a situation may occur where the opening 110
is formed in a countersink area of the rolling cutter body. Thus,
the present invention should not be considered as limited to its
use with respect to the installation of inserts 100 at any
particular region or location in a rolling cutter body.
[0030] FIG. 7 is provided to depict at least some of the
differences between an insert 100 in accordance with one
illustrative embodiment and at least some prior art cutting
inserts. The solid lines in FIG. 7 depict an insert 100 in
accordance with one illustrative embodiment of the present
invention. As shown therein, the insert 100 is comprised of the
rounded corner region 104, the generally cylindrical section 105,
the radiused region 106 and the tapered surface 107. Also depicted
in FIG. 7 is a dashed line which indicates a portion of the
structure of the prior art insert 20 depicted in FIGS. 3 and 4.
Specifically, the tapered surface 64 and rounded corner 65 of the
insert 20 depicted in FIG. 3 are indicated by the dashed lines. As
can be seen in FIG. 7, the bottom portion 108 of an insert 100 in
accordance with one embodiment of the present invention comprises a
bump 130, or region of additional material, as compared to the
prior art insert depicted in FIGS. 3 and 4. More specifically, this
region of material 130 is positioned between the bottom surface 102
and the tapered surface 107 and lies outside of a volume defined,
at least in part, by an intersection of a linear extension of the
tapered surface 107 with the bottom surface 102. Stated another
way, the bottom portion 108 of the insert 100 is configured such
that this region of material 130 is positioned at some location
between the bottom surface 102 and the tapered surface 107. Of
course, by stating that the region of material 130 is between the
bottom surface 102 and the tapered surface 107, it should be
understood that, in some applications, the region of material 130
may extend to and contact the tapered surface 107 and/or the bottom
surface 102. Transition regions, e.g., radiused regions, may also
be provided between the region of material 130 and the bottom
surface 102 and/or the tapered surface 107.
[0031] This additional region of material or bump 130 provides many
advantages as it relates to the alignment of the insert 100 with an
opening formed in the cutter body. More specifically, due to the
presence of the region of material 130, the misalignment between
the centerline 109 of the insert 100 and the centerline of the
opening 110 may be limited to, in one illustrative embodiment,
approximately 6-8 degrees. That is, as the misalignment between the
insert 100 and the opening 110 approaches this 6-8 degree value,
the bump 130 engages portions of the interior surface 115 (see FIG.
6) of the opening 110, thereby limiting the degree of misalignment.
Moreover, due to the presence of the bump 130, and perhaps the
radiused corner region 104, a relatively slight axial force 140
applied to the end of the insert 100 tends to cause the insert 100
to become more aligned with the centerline of the opening 110.
Accordingly, inserts in accordance with the present invention may
be readily aligned and installed without the need for prior art
guide devices and/or the use of manual labor to attempt to properly
align the insert as the insert is being inserted into the opening
110. Of course, if desired, a guide device may also be employed
with inserts 100 of the present invention. Once the pressing
operations are begun, and the insert body 101 is at least partially
positioned within the opening 110, the pressing operations may be
continued to fully install the insert 100 in the opening 110.
[0032] The present invention is generally directed to various
embodiments of self-aligning insert for use with rolling cutter
drill bits. In one illustrative embodiment, the insert comprises a
generally cylindrical body, a cutting surface, a bottom surface, a
tapered surface adjacent the generally cylindrical body, and a
generally cylindrical section positioned between the bottom surface
and the tapered surface. The inserts described herein may be
installed in openings formed in the roller cone bodies of a roller
cone drill bit.
[0033] In another illustrative embodiment, the insert comprises a
generally cylindrical body, a cutting surface, a bottom surface, a
tapered surface adjacent the generally cylindrical body, a radiused
corner region adjacent the bottom surface, and a generally
cylindrical section positioned between the radiused corner region
and the tapered surface, wherein the radiused corner region defines
a transition between the bottom surface and the generally
cylindrical section.
[0034] In yet another illustrative embodiment, the insert comprises
a generally cylindrical body, a cutting surface, a bottom surface,
a tapered surface adjacent the generally cylindrical body, a
radiused corner region adjacent the bottom surface, a generally
cylindrical section positioned between the radiused corner region
and the tapered surface, wherein the radiused corner region defines
a transition between the bottom surface and the generally
cylindrical section, and a radiused region positioned between the
tapered surface and the generally cylindrical section, wherein the
radiused region defines a transition between the generally
cylindrical section and the tapered surface.
[0035] In a further illustrative embodiment, the insert comprises a
generally cylindrical body, a cutting surface, a bottom surface, a
tapered surface adjacent the generally cylindrical body, and a
region of material positioned between the bottom surface and the
tapered surface, the region of material positioned outside of a
volume defined, at least in part, by an intersection of a linear
extension of the tapered surface with the bottom surface.
[0036] In yet a further illustrative embodiment, the insert
comprises a generally cylindrical body, a cutting surface, and a
bottom portion extending from the generally cylindrical body, the
bottom portion comprising a bottom surface and a tapered surface,
the tapered surface being formed adjacent the generally cylindrical
body, wherein the bottom portion is configured such that there is a
region of material positioned between the bottom surface and the
tapered surface, the region of material being positioned outside of
a volume defined, at least in part, by an intersection of a linear
extension of the tapered surface with the bottom surface.
[0037] The particular embodiments disclosed above are illustrative
only, as the invention may be modified and practiced in different
but equivalent manners apparent to those skilled in the art having
the benefit of the teachings herein. For example, the process steps
set forth above may be performed in a different order. Furthermore,
no limitations are intended to the details of construction or
design herein shown, other than as described in the claims below.
It is therefore evident that the particular embodiments disclosed
above may be altered or modified and all such variations are
considered within the scope and spirit of the invention.
Accordingly, the protection sought herein is as set forth in the
claims below.
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