U.S. patent application number 13/750423 was filed with the patent office on 2013-08-01 for drill bit.
This patent application is currently assigned to DIAMOND INNOVATIONS INC.. The applicant listed for this patent is Diamond Innovations Inc., Sandvik Intellectual Property AB. Invention is credited to Dwight E. Dyer, Joseph Fader, Kenneth Monyak, Adrienne Schmoll.
Application Number | 20130192902 13/750423 |
Document ID | / |
Family ID | 47603643 |
Filed Date | 2013-08-01 |
United States Patent
Application |
20130192902 |
Kind Code |
A1 |
Monyak; Kenneth ; et
al. |
August 1, 2013 |
Drill Bit
Abstract
A drill bit features a head portion and a connecting portion for
attachment to a drilling device. The head portion includes at least
two insert pockets, which can contain inserts, with cutting edges
that extend from an inner position offset radially from the
rotational axis of the bit to an outer cutting edge. The cutting
edge is formed by the intersection of a top surface and a wear
surface of the insert pocket or insert. The top surface is linear,
but may be planar or non-planar.
Inventors: |
Monyak; Kenneth; (Abingdon,
VA) ; Fader; Joseph; (Graz, AT) ; Schmoll;
Adrienne; (Westerville, OH) ; Dyer; Dwight E.;
(Kingston, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sandvik Intellectual Property AB;
Diamond Innovations Inc.; |
Sandviken
Worthington |
OH |
SE
US |
|
|
Assignee: |
DIAMOND INNOVATIONS INC.
Worthington
OH
SANDVIK INTELLECTUAL PROPERTY AB
Sandviken
|
Family ID: |
47603643 |
Appl. No.: |
13/750423 |
Filed: |
January 25, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61592215 |
Jan 30, 2012 |
|
|
|
Current U.S.
Class: |
175/426 ;
175/327 |
Current CPC
Class: |
E21B 10/5673 20130101;
E21B 10/62 20130101; E21B 10/46 20130101; E21B 10/00 20130101; E21B
10/58 20130101; E21B 10/55 20130101 |
Class at
Publication: |
175/426 ;
175/327 |
International
Class: |
E21B 10/00 20060101
E21B010/00; E21B 10/46 20060101 E21B010/46 |
Claims
1. A drill bit comprising a head portion and a connecting portion
for attachment to a drilling device, the head portion comprises at
least two insert pockets each including an insert with cutting
edges that extend from an inner position offset radially from the
rotational axis of the bit to a linear outer cutting edge, wherein
the inserts are skewed in relation to radii of the drill bit.
2. The drill bit according to claim 1, wherein the inserts are
raked back with a rake angle of about 10.degree. to about
30.degree..
3. The drill bit according to claim 1, wherein the inserts are
skewed with a skew angle of about -20.degree. to about
+20.degree..
4. The drill bit according to claim 3, wherein the inserts are
skewed with a positive skew angle.
5. The drill bit according to claim 1, wherein the inserts are
skewed with a skew angle of about 1.degree. to about
20.degree..
6. The drill bit according to claim 1, wherein the inserts are
leaned with a lean angle of about 10.degree. to about
30.degree..
7. The drill bit according to claim 1, wherein the inserts are
leaned with a lean angle of about 10.degree. to about 30.degree.
and are skewed with a skew angle of about 1.degree. to about
20.degree..
8. The drill bit according to claim 1, wherein the inserts are
skewed with a skew angle of about 1.degree. to about 20.degree. and
raked back with a rake angle of about 10.degree. to about
30.degree..
9. The drill bit according to claim 1, wherein the inserts are
formed of a substrate that is at least partially covered by a
superhard material.
10. The drill bit according to claim 9, wherein the substrate is
comprised of cemented carbide.
11. The drill bit according to claim 9, wherein the superhard
material is selected from the group consisting of diamond and cubic
boron nitride.
12. The drill bit according to claim 1, wherein the top surface of
the inserts have a non-planar surface.
13. The drill bit according to claim 12, wherein the non-planar
surface includes a wavy surface extending along a linear path.
14. The drill bit according to claim 13, wherein crests of the wavy
surface of one insert are radially offset from the crests of the
wavy surfaces of other inserts.
15. The drill bit according to claim 13, wherein the wavy surface
of one insert is 180.degree. out of phase with another insert.
16. A drill bit comprising a head portion and a connecting portion
for attachment to a drilling device, the head portion comprises at
least two insert pockets each including an insert with cutting
edges that extend from an inner position offset radially from the
rotational axis of the bit to a linear outer cutting edge, wherein
the inserts are skewed in relation to radii of the drill bit, and
wherein the inserts have a top surface that is non-planar extending
along a linear path.
17. The drill bit according to claim 16, wherein the top surface
includes a wavy surface that extends along a linear path.
18. The drill bit according to claim 16, wherein crests of the
waves on the top surfaces of the inserts are radially offset from
the waves on the top surface of any other insert in the drill
bit.
19. A drill bit comprising a head portion and a connecting portion
for attachment to a drilling device, the head portion comprises at
least two insert pockets each including an insert with cutting
edges that extend from an inner position offset radially from the
rotational axis of the bit to a linear outer cutting edge, wherein
the inserts are raked back with a rake angle of about 10.degree. to
about 30.degree., skewed with a skew angle of about 1.degree. to
about 20.degree., and leaned with a lean angle of about 10.degree.
to about 30.degree..
20. The drill bit according to claim 19, wherein a distance between
the cutting edges of the inserts formed by being offset radially
from the rotational axis of the bit is from about 25% to about 75%
of a total diameter of the drill bit.
Description
FIELD
[0001] The present disclosure relates to a drill bit and a drilling
device including the drill bit. The drill bit includes at least two
insert pockets with cutting edges that extend from an inner
position offset radially from the rotational axis of the bit to a
linear outer cutting edge. More particularly, the disclosure
relates to drill bits for boring and drilling in mining and
construction.
BACKGROUND
[0002] In the discussion of the background that follows, reference
is made to certain structures and/or methods. However, the
following references should not be construed as an admission that
these structures and/or methods constitute prior art. Applicant
expressly reserves the right to demonstrate that such structures
and/or methods do not qualify as prior art.
[0003] In the past, drill bits used in mining and construction have
been constructed with sintered carbide inserts to prolong the
operative life of the tool. In particular during mining operations,
the roof of the mine must be supported. This has traditionally been
accomplished by bolting support plates to the roof, the bolts being
installed in pre-drilled holes in the mine roof. It has been
conventional to drill the bolt-receiving holes by using a drill bit
on which is mounted a cutting insert.
[0004] A principal problem encountered in these prior art tools has
been the rapid wear and high cost of replacement along with machine
down-time. It is believed that a primary and inherent contributing
factor in tool wear and breakage has been the conventional design
of such drill bits, including the blade geometry and the
compositions used. To improve the tool wear and breakage properties
of the tools, tougher compositions for the bit inserts have been
used, such as superhard material.
[0005] Existing drill bits include either a non-coring
substantially continuous curved cutting edge extending from its
high entry point beyond the outer gauge-cutting margins or a
coring-type rotary drill bit having non-linear type working
surfaces.
[0006] FIG. 9 shows a non-coring drill bit with a continuous planar
cutting edge extending from its high entry point in both directions
to the outer margin. Cutting inserts may be positioned in insert
pockets open to opposite sides of the drill bit.
[0007] Examples of drill bits are shown in U.S. Pat. Nos.
5,383,526, 5,535,839, and 5,375,672. None of these references
contain enhanced blade geometry and use of superhard materials that
can lead to improved wear resistance and longer tool life.
SUMMARY
[0008] To improve the wear resistance and tool life of the drill
bits used in mining and construction, a new drill bit was designed
having a new blade geometry. The new blade geometry enables the
formation of drill bits having the benefit of a superhard material
with a geometry that extends the life of the inserts and drill
bit.
[0009] An exemplary drill bit includes a head portion and a
connecting portion for attachment to a drilling device. The head
portion includes at least two insert pockets each including an
insert with cutting edges that extend from an inner position offset
radially from the rotational axis of the bit to a linear outer
cutting edge.
[0010] A further exemplary drill bit includes a head portion and a
connecting portion for attachment to a drilling device. The head
portion includes at least two insert pockets each including an
insert with cutting edges that extend from an inner position offset
radially from the rotational axis of the bit to a linear outer
cutting edge. The inserts have a top surface that is non-planar
extending along a linear path.
[0011] A yet further exemplary drill bit includes a head portion
and a connecting portion for attachment to a drilling device. The
head portion includes at least two insert pockets each including an
insert with cutting edges that extend from an inner position offset
radially from the rotational axis of the bit to a linear outer
cutting edge. The inserts are raked back with a rake angle of about
10.degree. to about 30.degree., skewed with a skew angle of about
1.degree. to about 20.degree., and leaned with a lean angle of
about 10.degree. to about 30.degree.
[0012] An exemplary drilling device includes a drill bit according
to any of the embodiments described above.
[0013] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The following detailed description can be read in connection
with the accompanying drawings in which like numerals designate
like elements and in which:
[0015] FIG. 1 shows a perspective view of an exemplary embodiment
of a drill bit containing two inserts offset radially from the
rotational axis of the bit.
[0016] FIG. 2 shows a front view of the drill bit illustrated in
FIG. 1.
[0017] FIG. 3 shows a side view of the drill bit illustrated in
FIG. 1.
[0018] FIG. 4 shows a top view from the upper side of the drill bit
illustrated in FIG. 1.
[0019] FIG. 5 shows a perspective view of another exemplary
embodiment of a drill bit containing two inserts offset radially
from the rotational axis of the bit.
[0020] FIG. 6 shows a front view of the drill bit illustrated in
FIG. 5.
[0021] FIG. 7 shows a side view of the drill bit illustrated in
FIG. 5.
[0022] FIG. 8 shows a top view from the upper side of the drill bit
illustrated in FIG. 5.
[0023] FIG. 9 illustrates a prior art drill bit containing a
continuous cutting edge extending from a leading cutting edge in
both directions to the outer margins of the drill bit.
DETAILED DESCRIPTION
[0024] An exemplary embodiment of a drill bit containing two insert
pockets offset radially from the rotational axis of the bit is
shown in FIGS. 1-4. The drill bit is designed to rotate about the
rotational axis of the bit. The drill bit 20 includes a head
portion 26 and a connecting portion 22 for attachment to a drilling
device (not shown). The connecting portion 22 can include a bolt
hole 24 or other connecting structure for attachment.
[0025] The head portion 26 contains at least two insert pockets 28,
which contain inserts 30. In further embodiments, the head portion
26 may contain three, four or more insert pockets and respective
inserts. The inserts are distributed evenly around an open core.
For example, if the head portion contains two inserts, the inserts
are approximately 180.degree. apart. Similarly, for example, if
three inserts, then they are each approximately 120.degree. apart,
and if four inserts, then they are each approximately 90.degree.
apart.
[0026] Each insert 30 includes at least a cutting edge 32, outer
cutting edge 34, top surface 36, wear surface 38, inner surface 40,
and outer surface 42. With particular reference to FIG. 4, the
inner surface 40 of each insert 30 faces the open core 44 located
at the rotational axis of the drill bit 20. The wear surface 38 and
top surface 36 intersect to form the cutting edge 32, and the wear
surface 38 and outer surface 42 intersect to form the outer cutting
edge 34. The wear surface 38 serves as a chip face for the cutting
edge 32, because it faces the direction of the rotation of the
drill bit.
[0027] In FIGS. 1-4, the inserts 30 are set in insert pockets 28 to
form the wear surface. The inserts 30 are polygonal in shape with
linear, planar cutting edges 32, 34 and angular corners. The
inserts may be set in the insert pockets by chemical or mechanical
attachment, including, for example, brazing, using a set screw or
clamp, or adhesively bonding using a structural adhesive.
[0028] The inserts may be formed of a superhard material or of a
cemented carbide base with a superhard material fused to the base
as a working wear surface. The cemented carbide is preferably
tungsten carbide. The superhard material may be diamond, cubic
boron nitride, or any other material with similar hardness
properties. Exemplary hardness properties for suitable superhard
materials have a Knoop hardness number greater than 2000 HK.
Specifically, the superhard material may be polycrystalline
diamond.
[0029] In certain embodiments, the superhard material covers the
top surface 36, wear surface 38, outer surface 42, and/or inner
surface 40. During drilling operations, the top surface 36 of the
insert 30 will be the leading entry surface in contact with the
rock or other material to be drilled. Similarly, the outer surface
42 contacts the rock or other material to be drilled by being the
outermost surface in contact with the radial extent of the drilled
hole. The inner surface 40 will contact and help break up the core
of rock or other material to be drilled formed by the gap in the
rotational sweep of the top surface 36 of each insert formed by the
inserts being offset from the rotational axis. Further, the wear
surface 38 functions as the chip face. Therefore, any of the four
surfaces may contain a superhard material to extend tool life.
Further, in other embodiments, all surfaces of the inserts may be
covered with superhard material, which can be beneficial in
simplifying the manufacturing steps.
[0030] In other embodiments, other parts of the head portion 26 may
also be formed of a similar substrate covered by a superhard
material. In some embodiments, the insert pockets, especially top
surfaces and/or outer surfaces of the insert pockets, may be
covered by a superhard material to add strength and wear resistance
to the wear surfaces for reasons similar to their use on
corresponding surfaces of the inserts. Further, in other
embodiments, the entire head portion may be covered by the
superhard material.
[0031] FIGS. 5-8 illustrate another exemplary embodiment of a drill
bit 120 similar to the drill bit illustrated in FIGS. 1-4. The
drill bit 120 includes a head portion 126 and a connecting portion
122 for attachment to a drilling device (not shown). The connecting
portion 122 can include a bolt hole 124 or other connecting
structure for attachment.
[0032] The head portion 126 contains at least two insert pockets
128, which contain inserts 130. The head portion 126 may also
include additional insert pockets and inserts in similar manner as
head portion 26 illustrated in FIGS. 1-4.
[0033] Each insert 130 contains four linear edges with angular
corners including cutting edge 132, outer cutting edge 134, top
surface 136, wear surface 138, inner surface 140, and outer surface
142. The top 136, wear 138, inner 140, and outer 142 surfaces each
extend substantially along a linear path, but at least the top
surface 136 is linear but non-planar. The non-planar surfaces may
include a wavy, serrated, notched, or stepped surface. In the
embodiment of FIGS. 5-8, the top surface 136 includes a wavy
surface. In a particular embodiment, the top surfaces include
offset waves, where the waves of a top surface on one insert is
180.degree. out of phase with the top surface of the other insert.
Similar designs can be applied when more than two insert pockets
are included in the head portion. For example, if there are three
insert pockets, then the waves of the top surface of each insert
and insert pocket is 120.degree. out of phase with the other two
insert pockets.
[0034] In further embodiments, other surfaces of the insert may be
non-planar. For example, the inner surface of the insert may
include a non-planar surface to help break out the core produced
during the drilling operations. Similarly, the outer surface of the
insert may include a non-planar surface to help score out the hole
being drilled. The top, inner, and outer surfaces may include any
alternative design including waves, serrations, notches or steps,
where the design on each insert is arranged on the respective
surface such that the designs are in-line or offset when rotating
during drilling operations. Preferably, the designs are offset so
as to evenly distribute the cutting forces across each of the
inserts.
[0035] It was discovered that another factor leading to extended
tool life, is how the at least two inserts are positioned in
relation to the overall drill bit. The positioning of the inserts
can be defined by the rake angle, skew angle, and lean angle. As
illustrated in FIGS. 2 and 6, respectively, the rake angle
(.alpha., .alpha.') is the angle to which the linear path of the
top surface of the insert is raked back from being perpendicular to
the axial direction of the drill bit. In certain embodiments, the
rake angle is from about 10.degree. to about 30.degree.. In
specific embodiments, the rake angle is from about 15.degree. to
about 25.degree.. In more specific embodiments, the rake angle is
about 20.degree..
[0036] As illustrated in FIGS. 4 and 8, respectively, the skew
angle (.gamma., .gamma.') is the angle to which the back surface of
the insert connected to the insert pocket is skewed from a radius
of the drill bit. For example, in embodiments in which there are
two inserts, the skew angle is the angle to which the two insert
pockets are skewed from being parallel to each other. In other
embodiments in which there are more than two insert pockets, the
skew angle would include the angle to which the insert pockets are
skewed from being parallel with radii evenly spaced around the
drill bit. For example, in embodiments in which there are three
insert pockets, the skew angle would include the angle to which
each insert pocket is skewed from its complementary radius, wherein
each complementary radius is 120.degree. apart. The skew angle may
be positive or negative. A positive skew is in the direction
opposite the rotation of the drill bit. A negative skew is in the
direction of the rotation of the drill bit. At least when the skew
angle has a small absolute value, a positive skew brings the
cutting edge and wear face closer to the rotational axis of the
drill bit, and a negative skew takes the cutting edge and wear face
further from the rotational axis of the drill bit. In certain
embodiments, the skew angle is from about -20.degree. to about
+20.degree.. In specific embodiments, the skew angle is positive.
In more specific embodiments, the skew angle is from about
+1.degree. to about +20.degree.. In yet more specific embodiments,
the skew angle is from about +5.degree. to about +15.degree.. In
further specific embodiments, the skew angle is from about
+5.degree. to about +10.degree..
[0037] As illustrated in FIGS. 3 and 7, the lean angle (.beta.,
.beta.') is the angle to which the wear surface is leaned back from
parallel to the axial direction. In certain embodiments, the lean
angle is from about 10.degree. to about 30.degree.. In specific
embodiments, the lean angle is from about 15.degree. to about
25.degree.. In more specific embodiments, the lean angle is from
about 18 to about 22.degree.. In yet a more specific embodiment,
the lean angle is about 20.degree..
[0038] Because the insert pockets are offset with certain rake,
skew, and lean angles, the inserts are positioned a certain
distance from each other. This distance between the inserts
adjacent the top surfaces can be from about 25% to about 75% of the
total diameter of the drill bit. In certain embodiments, the
distance is from about 25% to about 60%. In further embodiments,
the distance is from about 25% to about 40%. In yet further
embodiments, the distance is from about 30% to about 35%.
[0039] The distance between the inserts often times can be shorter
when measured at the portion of the head portion closest to the
connecting portion of the drill bit. The distance between the
inserts at the portion of the head portion closest to the
connection portion can be from about 2% to about 30%. In certain
embodiments, the distance is from about 5% to about 20%. In further
embodiments, the distance is from about 10% to about 15%. In yet
further embodiments, the distance is from about 5% to about
10%.
[0040] Although described in connection with preferred embodiments
thereof, it will be appreciated by those skilled in the art that
additions, deletions, modifications, and substitutions not
specifically described may be made without departure from the
spirit and scope of the invention as defined in the appended
claims.
* * * * *