U.S. patent application number 13/871012 was filed with the patent office on 2014-10-30 for radial cutter bit with cutting insert having edge preparation.
This patent application is currently assigned to Kennametal Inc.. The applicant listed for this patent is KENNAMETAL INC.. Invention is credited to Stephen M. George, Nicholas J. Paros, Don C. Rowlett, Glenn W. Sheffler.
Application Number | 20140319898 13/871012 |
Document ID | / |
Family ID | 51685168 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140319898 |
Kind Code |
A1 |
Paros; Nicholas J. ; et
al. |
October 30, 2014 |
RADIAL CUTTER BIT WITH CUTTING INSERT HAVING EDGE PREPARATION
Abstract
A radial cutter bit includes a non-rotatable shank portion, a
head portion including a tip region distal from the non-rotatable
shank portion, and a cutting insert mounted at the tip region of
the head portion. The cutting insert includes a body having a
leading face, an opposing trailing face, a first side and a second
side. The leading face has a central face portion, a first side
face portion extending toward the first side of the body and a
second face portion extending toward the second side of the body.
The cutting insert further includes a top surface having a relief
surface, a T-land surface extending between at least a portion of
the leading face and the relief surface of the top surface and a
cutting edge formed at the intersection of the T-land surface and
the relief surface of the top surface.
Inventors: |
Paros; Nicholas J.;
(Johnstown, PA) ; George; Stephen M.; (Greensboro,
NC) ; Sheffler; Glenn W.; (Blairsville, PA) ;
Rowlett; Don C.; (Bedford, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KENNAMETAL INC. |
Latrobe |
PA |
US |
|
|
Assignee: |
Kennametal Inc.
Latrobe
PA
|
Family ID: |
51685168 |
Appl. No.: |
13/871012 |
Filed: |
April 26, 2013 |
Current U.S.
Class: |
299/113 |
Current CPC
Class: |
E21C 35/183 20130101;
E21C 35/19 20130101 |
Class at
Publication: |
299/113 |
International
Class: |
E21C 35/19 20060101
E21C035/19 |
Claims
1. A radial cutter bit for engaging an earth strata material, the
radial cutter bit comprising: a non-rotatable shank portion; a head
portion integrally formed with the non-rotatable shank portion and
including a tip region distal from the non-rotatable shank portion;
and a cutting insert mounted at the tip region of the head portion,
wherein the cutting insert comprises: a body having a leading face,
an opposing trailing face, a first side and a second side; the
leading face having a central face portion, a first side face
portion extending toward the first side of the body and a second
face portion extending toward the second side of the body; a top
surface having a relief surface; a T-land surface extending between
at least a portion of the leading face and the relief surface of
the top surface; and a cutting edge formed at the intersection of
the T-land surface and the relief surface of the top surface.
2. The radial cutter bit of claim 1, wherein the T-land surface
includes a central T-land surface extending between the central
face portion of the leading face and the relief surface of the top
surface.
3. The radial cutter bit of claim 2, wherein the cutting edge
includes a central cutting edge formed at the intersection of the
central T-land surface and the relief surface of the top
surface.
4. The radial cutter bit of claim 3, wherein the central cutting
edge has a negative axial rake angle.
5. The radial cutter bit of claim 1, wherein the T-land surface
includes a first side T-land surface extending between the first
side face portion of the leading face and the relief surface of the
top surface.
6. The radial cutter bit of claim 5, wherein the cutting edge
includes a first side cutting edge formed at the intersection of
the first side T-land surface and the relief surface of the top
surface.
7. The radial cutter bit of claim 6, wherein the first side cutting
edge has a negative axial rake angle.
8. The radial cutter bit of claim 1, wherein the T-land surface
includes a second side T-land surface extending between the second
side face portion of the leading face and the relief surface of the
top surface.
9. The radial cutter bit of claim 8, wherein the cutting edge
includes a second side cutting edge formed at the intersection of
the second side T-land surface and the relief surface of the top
surface.
10. The radial cutter bit of claim 9, wherein the second side
cutting edge has a negative axial rake angle.
11. A cutting insert for use in connection with a cutter bit for
engaging an earth strata material, the cutting insert comprising: a
body having a leading face, an opposing trailing face, a first side
and a second side; the leading face having a central face portion,
a first side face portion extending toward the first side of the
body and a second face portion extending toward the second side of
the body; a top surface having a relief surface; a T-land surface
extending between at least a portion of the leading face and the
relief surface of the top surface; and a cutting edge formed at the
intersection of the T-land surface and the relief surface of the
top surface.
12. The cutting insert of claim 11, wherein the T-land surface
includes a central T-land surface extending between the central
face portion of the leading face and the relief surface, the
cutting edge includes a central cutting edge formed at the
intersection of the central T-land surface and the relief surface,
and the central cutting edge has a negative axial rake angle.
13. The cutting insert of claim 12, wherein the T-land surface
includes a first side T-land surface extending between the first
side face portion of the leading face and the relief surface, the
cutting edge includes a first side cutting edge formed at the
intersection of the first side T-land surface and the relief
surface, and the first side cutting edge has a negative axial rake
angle.
14. The cutting insert of claim 13, wherein the T-land surface
includes a second side T-land surface extending between the second
side face portion of the leading face and the relief surface, the
cutting edge includes a second side cutting edge formed at the
intersection of the second side T-land surface and the relief
surface, and the second side cutting edge has a negative axial rake
angle.
15. The cutting insert of claim 12, wherein the negative axial rake
angle of the central cutting edge is in the range of about 10
degrees to about 60 degrees.
16. The cutting insert of claim 13, wherein the negative axial rake
angle of the first side cutting edge is in the range of about 10
degrees to about 60 degrees.
17. The cutting insert of claim 14, wherein the negative axial rake
angle of the second side cutting edge is in the range of about 10
degrees to about 60 degrees.
Description
BACKGROUND OF THE INVENTION
[0001] The invention pertains generally to an excavating tool such
as, for example, a cutter bit useful for cutting through various
earth strata and other materials. More specifically, the invention
pertains to a radial cutter bit with a cutting insert having edge
preparation.
[0002] Various types of cutting assemblies having cutter bits are
used for mining, construction and related operations wherein,
typically, the cutter bits include a shank for insertion into a
tool holder and a forward working portion on the shank for
engagement with earth strata, e.g., coal, or mineral formation or
other natural materials or the like. An individual insert formed of
a hard, wear resistant material is provided on the forward working
portion to cut into the earth strata and to enhance the life of the
cutter bit as it removes the material.
[0003] An example of a cutting assembly having cutter bits that are
used for mining and construction operations is a radial cutter
tool. These types of cutting tools usually include a plurality of
cutter bits mounted on a rotatable disc, rake, chain, barrel or
drum, wherein each of the cutter bits include a substantially-flat
cutting insert made of a hard material. These substantially-flat
cutting inserts are affixed to the forward working end of the
cutter bits. However, it has been determined that due to the shape
and configuration of the substantially-flat cutter inserts, the
cutter inserts do not wear uniformly. This non-uniform wear
decreases the overall useful life of the cutting inserts. More
particularly, the cutting edge of the substantially-flat cutter
inserts have a tendency to chip or break during use due to the
shape of the cutting edge.
[0004] Accordingly, it would be desirable to provide improved
cutting tools that overcome limitations and disadvantages of known
such tools. In addition, it would be desirable to provide improved
cutter bits that overcome limitations and disadvantages of known
cutter bits and that provide for improved wear and efficiency
during operation. Furthermore, it would be desirable to provide
improved cutting inserts for cutter bits that overcome limitations
and disadvantages of known cutting inserts and that provide for
improved wear and efficiency during operation.
SUMMARY OF THE INVENTION
[0005] In accordance with an aspect of the invention, a radial
cutter bit for engaging an earth strata material includes a
non-rotatable shank portion, a head portion integrally formed with
the non-rotatable shank portion and including a tip region distal
from the non-rotatable shank portion, and a cutting insert mounted
at the tip region of the head portion. The cutting insert includes
a body having a leading face, an opposing trailing face, a first
side and a second side. The leading face has a central face
portion, a first side face portion extending toward the first side
of the body and a second face portion extending toward the second
side of the body. The cutting insert further includes a top surface
having a relief surface, a T-land surface extending between at
least a portion of the leading face and the relief surface of the
top surface and a cutting edge formed at the intersection of the
T-land surface and the relief surface of the top surface.
[0006] In accordance with another aspect of the invention, a
cutting insert for use in connection with a cutter bit for engaging
an earth strata material includes a body having a leading face, an
opposing trailing face, a first side and a second side. The leading
face has a central face portion, a first side face portion
extending toward the first side of the body and a second face
portion extending toward the second side of the body. The cutting
insert further includes a top surface having a relief surface, a
T-land surface extending between at least a portion of the leading
face and the relief surface of the top surface and a cutting edge
formed at the intersection of the T-land surface and the relief
surface of the top surface.
[0007] These and other aspects of the present invention will be
more fully understood following a review of this specification and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a side view of a cutter bit, e.g. a radial cutter
bit, in accordance with an aspect of the invention.
[0009] FIG. 2 is a front view of the cutter bit shown in FIG. 1, in
accordance with an aspect of the invention.
[0010] FIG. 3 is a front view of a cutting insert for use with the
cutter bit shown in FIGS. 1 and 2, in accordance with an aspect of
the invention.
[0011] FIG. 4 is a top view of the cutting insert shown in FIG. 3,
in accordance with an aspect of the invention.
[0012] FIG. 4A is a sectional view taken along line 4A-4A of FIG.
4, in accordance with another aspect of the invention.
[0013] FIG. 4B is a sectional view taken along line 4B-4B of FIG.
4, in accordance with another aspect of the invention.
[0014] FIG. 4C is a sectional view taken along line 4C-4C of FIG.
4, in accordance with another aspect of the invention.
DETAILED DESCRIPTION
[0015] The following description is for purposes of illustrating
various aspects of the invention only and not for purposes of
limiting the scope of the invention.
[0016] Referring to FIGS. 1-4C, there is illustrated a cutter bit
in the form of, for example, a radial cutter bit generally
designated as 10, and a cutting insert generally designated as 22
for use therewith. The radial cutter bit 10 includes a shank
portion 12 that is non-rotatable, i.e. the shank portion 12 does
not rotate during operation once the radial cutter bit 10 is
assembled by inserting the shank portion 12 of the radial cutting
tool 10 into a tool holder base (not shown). In one aspect, the
shank portion 12 has a generally non-circular cross-section, e.g. a
generally rectangular cross-section.
[0017] The radial cutter bit 10 includes a forward working end that
includes a head portion 14 integrally formed with the shank portion
12 and having a tip region 16 distal from the shank portion 12. The
cutting insert 22 is mounted at the tip region 16 of the head
portion 14. The cutting insert 22 is typically mounted or affixed
to the head portion 14 by, for example, attaching mechanically or
otherwise, via brazing, gluing, or press fitting using conventional
compositions and techniques known to those skilled in the art.
[0018] The cutting insert 22 is made from, for example, a cemented
tungsten carbide that is a mixture of cobalt and tungsten carbide.
Other super hard, wear resistant materials such as polycrystalline
diamond, ceramics, or cermet may be used as a supplement and/or
substitute. For example chromium carbide-coated metals and other
cermets where titanium carbide or vanadium carbide is added to
tungsten carbide may be candidates for inserts materials in
accordance to aspects of the invention. Alternate ceramics for such
applications include aluminum-based, silicon based, zirconium-based
and glass varieties. Still other insert materials alternatives
include cubic refractory, transition metal carbides or any other
known or subsequently developed material(s) harder than the base
material. Also coatings of the inserts such as PVD or CVD coatings
can be used.
[0019] In one aspect, the cutting insert 22 is made, for example,
with a powder metallurgy process using a press comprising of a die
and top and bottom ram/punch to press the complete shape. Parts can
be pressed to finished shape or modified with a wet/dry blast, or
diamond ground other material shaping processes such as but not
limited to EDM (electrical discharge machining), EDG (electrical
discharge grinding), green machining, laser ablation into final
shapes. Advantageously, the invention provides for moving the
critical cutting edge of the insert from the intersection of the
die case and ram during manufacturing. In accordance with an aspect
of the invention, the critical cutting edge is now formed entirely
in the ram/punch. This eliminates the flash from forming on the
cutting edge. Flash is undesirable because, for example, it is a
stress concentrator. It will be appreciated that these and other
aspects of the invention as set forth herein contribute to the
desired edge, i.e. cutting edge, preparation for the cutting
insert.
[0020] Cutting insert 22 has a cutting insert body, generally
designated as 24, that has a top surface 26, a bottom surface 28, a
first side portion 34 and a second side portion 36. The cutting
insert body 24 also includes a leading face 40 and an opposite
rearward or trailing face 42.
[0021] The leading face 40 includes a central face portion 40a, a
first side face portion 40b extending toward the first side portion
34 of the body 24 and a second side face portion 40c extending
toward the second side portion 36 of the body 24. In one aspect,
the central face portion 40a is contiguous and non-coplanar with
the first side face portion 40b. In another aspect, the central
face portion 40a is contiguous and non-coplanar with the second
side face portion 40c.
[0022] The top surface 26 of the cutting insert 22 includes a
relief surface 44. In one aspect, the relief surface 44 extends
toward the rearward or trailing face 42 of the cutting insert 22.
In another aspect, the relief surface 44 extends to the rearward or
trailing face 42. In another aspect, the relief surface is
generally curved or arcuate.
[0023] In accordance with another aspect of the invention, the
cutting insert 22 includes edge preparation such as a T-land
surface, generally designated as 48, extending generally between at
least a portion of the leading face 40 and the relief surface 44 of
the top surface 26. In one aspect, the T-land surface 48 includes a
central T-land surface 48a extending between the central face
portion 40a of the leading face 40 and the relief surface 44 of the
top surface 26, a first side T-land surface 48b extending between
the first side face portion 40b of the leading face 40 and the
relief surface 44 of the top surface 26 and a second side T-land
surface 48c extending between the second side face portion 40c of
the leading face 40 and the relief surface 44 of the top surface
26. In one aspect, the central T-land surface 48a, the first side
T-land surface 48b and the second side T-land surface 48c are
contiguous with each other to provide for a continuous T-land
surface 48. In one aspect, the central T-land surface 48a is
contiguous with the central face portion 40a, the first side T-land
surface 48b is contiguous with the first side face portion 40b and
the second side T-land surface 48c is contiguous with the second
side face portion 40c. In another aspect, the central T-land
surface 48a is contiguous with the relief surface 44, the first
side T-land surface 48b is contiguous with the relief surface 44
and the second side T-land surface 48c is contiguous with the
relief surface 44. It will be appreciated that the T-land
surface(s) 48 may be planar surfaces or other than a planar
surface, such as, for example it may include a rounded or curved,
i.e. non-planar, T-land surface.
[0024] The cutting insert 22 further includes a cutting edge 50
formed at the intersection of the T-land surface 48 and the relief
surface 44 of the top surface 26. In one aspect, the cutting edge
50 includes a central cutting edge 50a formed at the intersection
of the central T-land surface 48a and the relief surface 44 of the
top surface 26, a first side cutting edge 50b formed at the
intersection of the first side T-land surface 48b and the relief
surface 44 of the top surface 26 and a second side cutting edge 50c
formed at the intersection of the second side T-land surface 48c
and the relief surface 44 of the top surface 26. In another aspect,
the central cutting edge 50a, the first side cutting edge 50b and
the second side cutting edge 50c are contiguous with each other to
provide for a continuous cutting edge 50. In another aspect, the
central cutting edge 50a, the first side cutting edge 50b and the
second side cutting edge 50c may be rounded or curved.
[0025] The configuration of having the central cutting edge 50a
formed at the intersection of the central T-land surface 48a and
the relief surface 44 provides for the cutting edge 50a to have a
negative axial rake angle Ra (see, for example, FIG. 4A). In one
aspect, the negative axial rake angle Ra is in the range of about
10 degrees to about 60 degrees. In one specific example, the rake
angle Ra shown in FIG. 4A is about negative 35 degrees.
[0026] The central T-land surface 48a is positioned relative to the
relief surface 44 at an angle Xa (see, for example, FIG. 4A). The
angle Xa may be referred to as a relief angle relative to or in
relation to cutting edge 50a. In one aspect, the T-land surface 48a
is positioned relative to the relief surface 44 at an angle Xa that
is greater than 90 degrees. In one specific example, the angle Xa
shown in FIG. 4A is about 110 degrees.
[0027] In another aspect, the central T-land surface 48a may have a
width Wa (see, for example, FIG. 4A) in the range of about 0.002
inches to about 0.090 inches. In one specific example, the width Wa
is about 0.010 inches.
[0028] The configuration of having the first side cutting edge 50b
formed at the intersection of the first side T-land surface 48b and
the relief surface 44 provides for the cutting edge 50b to have a
negative axial rake angle Rb (see, for example, FIG. 4B). In one
aspect, the negative axial rake angle Rb is in the range of about
10 degrees to about 60 degrees. In one specific example, the rake
angle Rb shown in FIG. 4B is about negative 50 degrees.
[0029] The first side T-land surface 48b is positioned relative to
the relief surface 44 at an angle Xb (see, for example, FIG. 4B).
The angle Xb may be referred to as a relief angle relative to or in
relation to cutting edge 50b. In one aspect, the first side T-land
surface 48b is positioned relative to the relief surface 44 at an
angle Xb that is greater than 90 degrees. In one specific example,
the angle Xb shown in FIG. 4B is about 125 degrees.
[0030] In another aspect, the first side T-land surface 48b may
have a width Wb (see, for example, FIG. 4B) in the range of about
0.002 inches to about 0.090 inches. In one specific example, the
width Wb is about 0.015 inches.
[0031] The configuration of having the second side cutting edge 50c
formed at the intersection of the second side T-land surface 48c
and the relief surface 44 provides for the cutting edge 50c to have
a negative axial rake angle Rc (see, for example, FIG. 4C). In one
aspect, the negative axial rake angle Rc is in the range of about
10 degrees to about 60 degrees. In one specific example, the rake
angle Rc shown in FIG. 4C is about negative 50 degrees.
[0032] The second side T-land surface 48c is positioned relative to
the relief surface 44 at an angle Xc (see, for example, FIG. 4C).
The angle Xc may be referred to as a relief angle relative to or in
relation to cutting edge 50c. In one aspect, the second side T-land
surface 48c is positioned relative to the relief surface 44 at an
angle Xc that is greater than 90 degrees. In one specific example,
the angle Xc shown in FIG. 4C is about 125 degrees.
[0033] In another aspect, the second side T-land surface 48c may
have a width Wc (see, for example, FIG. 4C) in the range of about
0.002 inches to about 0.090 inches. In one specific example, the
width Wc is about 0.015 inches.
[0034] It will be appreciated that the configuration of the
T-land(s) 48, cutting edge(s) 50, negative axial rake angle(s) R
and/or the relief angle(s) X individually and/or in combination
advantageously avoid a sharp transition for the cutting edge(s) 50
so as to reduce or minimize the possibility of the cutting edge
50(s) breaking or chipping during operation of the cutter bit 10.
In addition, the T-land(s) 48 is configured so as to redirect the
cutting forces along the cutting edge(s) 50 to reduce the shear
stress along the cutting edge(s) 50.
[0035] Whereas particular aspects of this invention have been
described above for purposes of illustration, it will be evident to
those skilled in the art that numerous variations of the details of
the present invention may be made without departing from the
invention as defined in the appended claims.
* * * * *