U.S. patent application number 12/880377 was filed with the patent office on 2011-03-24 for rotatable cutting tool with hard cutting member.
This patent application is currently assigned to Kennametal Inc.. Invention is credited to Randall W. Ojanen.
Application Number | 20110068616 12/880377 |
Document ID | / |
Family ID | 43755992 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110068616 |
Kind Code |
A1 |
Ojanen; Randall W. |
March 24, 2011 |
ROTATABLE CUTTING TOOL WITH HARD CUTTING MEMBER
Abstract
A rotatable cutting tool that is for impingement upon a
substrate and adapted to be rotatably retained within the bore of a
holder. The rotatable cutting tool includes an elongate cutting
tool body, which has an axial forward end and an axial rearward end
with a socket at the axial forward end thereof. The rotatable
cutting tool further has a hard cutting member, which is affixed to
the cutting tool body within the socket. The hard cutting member
has an axial forward end and an axial rearward end. The hard
cutting member has an axial forward functional portion which has a
starting transverse functional dimension, and further has a base
portion which has a maximum transverse base dimension. There is a
ratio of the starting transverse functional dimension to the
maximum transverse base dimension ranging between equal to 0.42 and
less than 0.48.
Inventors: |
Ojanen; Randall W.;
(Bristol, TN) |
Assignee: |
Kennametal Inc.
Latrobe
PA
|
Family ID: |
43755992 |
Appl. No.: |
12/880377 |
Filed: |
September 13, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61244228 |
Sep 21, 2009 |
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Current U.S.
Class: |
299/111 ;
299/110 |
Current CPC
Class: |
E21C 35/183 20130101;
E21C 35/1837 20200501 |
Class at
Publication: |
299/111 ;
299/110 |
International
Class: |
E21C 35/18 20060101
E21C035/18 |
Claims
1. A rotatable cutting tool for impingement upon a substrate and
adapted to be rotatably retained within the bore of a holder, the
rotatable cutting tool comprising: an elongate cutting tool body
having an axial forward end and an axial rearward end, the cutting
tool body containing a socket at the axial forward end thereof; a
hard cutting member being affixed to the cutting tool body within
the socket, and the hard cutting member having an axial forward end
and an axial rearward end; the hard cutting member having an axial
forward functional portion which has a starting transverse
functional dimension; the hard cutting member further having a base
portion which has a maximum transverse base dimension; and a ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.42 and less
than 0.48.
2. The rotatable cutting tool according to claim 1 wherein the
ratio of the starting transverse functional dimension to the
maximum transverse base dimension ranging between equal to 0.42 and
less than 0.479.
3. The rotatable cutting tool according to claim 1 wherein the
ratio of the starting transverse functional dimension to the
maximum transverse base dimension ranging between equal to 0.43 and
less than 0.455.
4. The rotatable cutting tool according to claim 1 wherein the
ratio of the starting transverse functional dimension to the
maximum transverse base dimension ranging between equal to 0.432
and less than 0.45.
5. A hard cutting member for attachment to a cutting tool body, the
hard cutting member comprising: an axial forward end and an axial
rearward end; an axial forward functional portion which has a
starting transverse functional dimension; a base portion which has
a maximum transverse base dimension; and a ratio of the starting
transverse functional dimension to the maximum transverse base
dimension ranging between equal to 0.42 and less than 0.48.
6. The hard cutting member according to claim 5 wherein the ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.42 and less
than 0.479.
7. The hard cutting member according to claim 5 wherein the ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.43 and less
than 0.455.
8. The hard cutting member according to claim 5 wherein the ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.432 and less
than 0.45.
9. A hard cutting member for attachment to a cutting tool body, the
hard cutting member comprising: an axial forward end and an axial
rearward end, an axial length being the distance between the axial
forward end and the axial rearward end; an axial forward functional
portion which has a starting transverse functional dimension; a
base portion which has a maximum transverse base dimension; a ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.42 and less
than 0.48, a ratio between the axial length and the maximum
transverse base dimension ranging between equal to 0.75 and less
than 0.78.
10. The hard cutting member according to claim 9 wherein the ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.42 and less
than 0.479.
11. The hard cutting member according to claim 9 wherein the ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.43 and less
than 0.455.
12. The hard cutting member according to claim 9 wherein the ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.432 and less
than 0.45.
13. The hard cutting member according to claim 9 wherein the ratio
of the axial length to the maximum transverse base dimension
ranging between equal to 0.76 and less than 0.78.
14. The hard cutting member according to claim 9 wherein the ratio
of the axial length to the maximum transverse base dimension
ranging between equal to 0.768 and less than 0.771.
Description
CROSS-REFERENCE TO EARLIER PATENT APPLICATION
[0001] This patent application is a continuation of co-pending
provisional U.S. Patent Application Ser. No. 61/244,228 filed Sep.
19, 2009 for ROTATABLE CUTTING TOOL WITH HARD CUTTING MEMBER by
Randal W. Ojanen. Applicant hereby claims priority on such U.S.
Patent Application Ser. No. 61/244,228 filed Sep. 19, 2009 for
ROTATABLE CUTTING TOOL WITH HARD CUTTING MEMBER by Randal W.
Ojanen. Further, applicant hereby incorporates by reference herein
the entirety of such U.S. Patent Application Ser. No. 61/244,228
filed Sep. 19, 2009 for ROTATABLE CUTTING TOOL WITH HARD CUTTING
MEMBER by Randal W. Ojanen.
BACKGROUND OF THE INVENTION
[0002] The invention pertains to a rotatable cutting tool, which
typically mounts in a stationary block (or holder) on a rotatable
drum. The rotatable cutting tool, which is rotatable about its
central longitudinal axis, carries a hard cutting insert at the
axially forward end thereof. The hard cutting insert is of a hard
material such as, for example, cemented (cobalt) tungsten carbide.
The rotatable cutting tool engages or impinges a substrate upon the
rotation of the drum. The hard cutting insert exhibits a geometry
that provides a number of benefits both in the operational
efficiency of the rotatable cutting tool and the cost of materials
to manufacture the rotatable cutting tool.
[0003] A rotatable cutting tool typically presents a generally
elongate, cylindrical geometry. The rotatable cutting tool
comprises an elongate steel cutting tool body, which has an axially
forward end and an opposite axially rearward end. The cutting tool
body typically carries an assembly or means by which the rotatable
cutting tool is rotatable carried by the stationary block or holder
on the drum. Exemplary structures useful for the rotatable
attachment of a rotatable cutting tool to a block or holder include
those shown and described in U.S. Pat. No. 4,201,41 to Den Besten
et al., U.S. Pat. No. 3,519,309 to Engle et al., U.S. Pat. No.
3,752,515 to Oaks et al., and U.S. Pat. No. 7,380,888 to Ojanen for
a Rotatable Cutting Tool having Retainer with Dimples.
[0004] A hard cutting member typically affixes, such as by brazing,
to the axial forward and of the cutting tool body. As mentioned
above, typically, the hard cutting member is made from a hard
material like cemented cobalt tungsten carbide. U.S. Pat. No.
4,389,074 to Greenfield, U.S. Pat. No. 5,131,725 to Rowlett et al.,
U.S. Pat. No. 5,429,199 to Sheirer et al., U.S. Pat. No. 6,375,272
to Ojanen, and U.S. Pat. No. 6,478,383 to Ojanen et al. disclose
braze alloys that have heretofore been suitable for such a brazing
operation and suitable compositions of cemented tungsten
carbide.
[0005] Heretofore, a hard cutting member suitable for use in a
rotatable cutting tools have exhibited many different geometries.
One exemplary geometry is shown and described in U.S. Pat. No.
4,497,520 to Ojanen.
[0006] In the case of a road planing machine, the rotatable drum
can in many cases carry hundreds of individual blocks or holders.
Each individual block or holder carries its own corresponding
rotatable cutting tool, which is rotatable relative to its
corresponding block or holder. It is not unusual that a rotatable
drum will carry hundreds of individual rotatable cutting tools.
[0007] The road planing machine powers the rotatable drum so as to
cause it to rotate. The orientation of the rotatable cutting tools
with respect to the drum is such so that upon rotation of the drum,
the drum drives the rotatable cutting tools into the substrate.
Upon the rotatable cutting tools impinging the substrate, the
substrate typically breaks thereby forming larger chunks of debris,
as well as smaller particles and pieces of debris. Typically, the
debris generated in a road planing operation is highly abrasive
which causes the rotatable cutting tool to experience wear.
[0008] The rotatable cutting tool can experience wear in a number
of ways. The hard cutting member, which is the portion of the
rotatable cutting bit that first impinges the substrate, can
experience wear. The initial impact of the hard cutting member
against the substrate, as well as the travel of the debris along
the hard cutting member, can cause this wear. Over the course of
the cutting operation, the hard cutting member can lose material to
the point where it becomes dull and ineffective to accomplish
efficient cutting.
[0009] Another wear mechanism pertains to the braze joint between
the hard cutting member and the elongate cutting tool body.
Throughout the course of the cutting operation, the braze joint
experiences severe stresses due to the continual intermittent
violent impingement of the rotatable cutting tool against the
substrate material. Over the course of time, the braze joint can
experience sufficient stress so as to fail thereby allowing the
hard cutting member to separate from the cutting tool body.
Obviously, if the rotatable cutting tool loses the hard cutting
member, the rotatable cutting tool is no longer useful for the
cutting operation.
[0010] Further, during a cutting operation such as, for example, a
road planing operation, debris travels down the elongate cutting
tool body. Due to the abrasive nature of the debris, the elongate
cutting tool body experiences wear and erosion. Since the cutting
tool body typically comprises steel, those in the pertinent art
characterize this wear phenomenon as "steel wash". The result of
"steel wash" is to cause the axial forward portion of the cutting
tool body beneath or axially behind the hard cutting member to
reduce in diameter. Such a reduction in diameter causes this
portion of the cutting tool body to take on an hourglass shape. As
the cutting operation continues, the axial forward portion of the
cutting tool body continues to reduce in diameter to a point where
it eventually breaks thereby ending the useful life of the
rotatable cutting tool due to the failure of the cutting tool
body.
[0011] One way to retard steel was has been to enlarge the size of
the base portion of the hard cutting insert. By enlarging the size
of the base portion, the hard cutting insert provides a greater
amount of protection to the axial forward end of the steel cutting
tool body. Along with enlarging the size of the base portion of the
hard cutting insert, there has been an enlargement of the overall
geometry of the hard cutting insert. By enlarging the overall size
of the hard cutting insert, there has been an increase in the cost
of materials for the rotatable cutting tool. Further, by enlarging
the overall size of the hard cutting insert, resistance to the
penetration of the hard cutting insert increases, and thus, more
power or energy is needed to drive the rotatable cutting tool
through the strata.
[0012] Steel wash has been (or can be) particularly acute in
cutting operations in which the substrate is soft asphalt. In
cutting soft asphalt, the rotatable cutting tool may cut to a depth
such that the steel body enters the cut. When this occurs, the
erosion or wash of the steel cutting tool body becomes significant
whereby the steel cutting tool body wears to an end of useful
condition prior to the hard cutting insert wearing to an end of
useful condition. This can be a disadvantageous condition because
the hard cutting insert contains an amount of useful cemented
tungsten carbide, and yet, the rotatable cutting tool is not useful
for cutting.
[0013] It would thus be highly desirable to provide an improved
rotatable cutting tool, which is rotatably carried by an individual
block or holder of a rotatable drum of a cutting machine (e.g., a
road planing machine), wherein the hard cutting insert does not
contain an amount of useful cemented tungsten carbide at the time
the steel cutting tool body reaches an end of useful life
condition. Further, it would be desirable to provide a hard cutting
insert that provides protection to the steel cutting tool body and
yet does not increase the power or energy necessary to drive the
rotatable cutting tool through the strata.
SUMMARY OF THE INVENTION
[0014] In one form thereof, the invention is a rotatable cutting
tool that is for impingement upon a substrate and adapted to be
rotatably retained within the bore of a holder. The rotatable
cutting tool includes an elongate cutting tool body, which has an
axial forward end and an axial rearward end with a socket at the
axial forward end thereof. The rotatable cutting tool further has a
hard cutting member, which is affixed to the cutting tool body
within the socket. The hard cutting member has an axial forward end
and an axial rearward end. The hard cutting member has an axial
forward functional portion which has a starting transverse
functional dimension, and further has a base portion which has a
maximum transverse base dimension. There is a ratio of the starting
transverse functional dimension to the maximum transverse base
dimension ranging between equal to 0.42 and less than 0.48.
[0015] In yet another form, the invention is a hard cutting member
for attachment to a cutting tool body. The hard cutting member
comprises an axial forward end, an axial rearward end, and an axial
forward functional portion, which has a starting transverse
functional dimension. The hard cutting member further has a base
portion, which has a maximum transverse base dimension. A ratio of
the starting transverse functional dimension to the maximum
transverse base dimension ranges between equal to 0.42 and less
than 0.48.
[0016] In still another form, the invention is a hard cutting
member for attachment to a cutting tool body. The hard cutting
member comprises an axial forward end and an axial rearward end.
The axial length is the distance between the axial forward end and
the axial rearward end. The hard cutting member has an axial
forward functional portion, which has a starting transverse
functional dimension, and a base portion which has a maximum
transverse base dimension. A ratio of the starting transverse
functional dimension to the maximum transverse base dimension
ranges between equal to 0.42 and less than 0.48. A ratio between
the axial length and the maximum transverse base dimension ranges
between equal to 0.75 and less than 0.78.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The following is a brief description of the drawings that
form a part of this patent application:
[0018] FIG. 1 is a side view of a rotatable cutting tool with a
hard cutting member at the axial forward end;
[0019] FIG. 2 is a side view of the hard cutting member of FIG. 1
wherein a portion of the axial forward end of the steel cutting
tool body is broken away showing the hard cutting member in the
socket and the braze joint between the hard cutting member and the
surface that defines the socket;
[0020] FIG. 3 is a side view of the hard cutting member of FIG. 2
shown not in the socket;
[0021] FIG. 4 is a side view of a second specific embodiment of a
hard cutting member; and
[0022] FIG. 5 is a side view of a third specific embodiment of a
hard cutting member.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0023] Referring to the drawings, FIG. 1 illustrates a first
specific embodiment of the rotatable cutting tool of the invention,
generally designated as 30. The specific embodiments illustrated
herein pertain to road planing tools. However, one should
appreciate that the invention has application to other kinds of
cutting tool useful in other kinds of cutting operations. Exemplary
operations include without limitation road planing (or milling),
coal mining, concrete cutting, and other kinds of cutting
operations wherein a cutting tool with a hard cutting member
impinges against a substrate (e.g., earth strata, pavement,
asphaltic highway material, concrete, and the like) breaking the
substrate into pieces of a variety of sizes including larger-size
pieces or chunks and smaller-sized pieces including dust-like
particles.
[0024] Rotatable cutting tool 30 has a central longitudinal axis
A-A. In operation, rotatable cutting tool 30 rotates about the axis
A-A. Rotatable cutting tool 30 includes an elongate cutting tool
body generally designated as 32, which typically is made of steel.
Exemplary compositions of the steel for the cutting tool body
include without limitation those disclosed in the following
document: U.S. Pat. No. 4,886,710 to Greenfield, and U.S. Pat. No.
5,008,073 to Greenfield. Elongate cutting tool body 32 presents a
generally cylindrical geometry, and has an axial forward end 34 and
an axial rearward end 36.
[0025] Elongate cutting tool body 32 includes a head portion 38,
which has an enlarged transverse dimension adjacent the axial
forward end 34 relative to the overall transverse dimension of the
cutting tool body. The elongate cutting tool body 32 further
includes an integral shank portion 40, which has a reduced
transverse dimension, adjacent the axial rearward end 36 relative
to the overall transverse dimension of the cutting tool body. The
shank portion 40 contains an annular groove 42 adjacent the axial
rearward end 36.
[0026] The head portion 38 contains a socket 44 at the axial
forward end of the cutting tool body 32. The socket 44 presents a
so-called flat-bottom geometry wherein the socket 44 has a
generally circular bottom surface 46 and a generally cylindrical
surface 48. One should appreciate that other geometries of a socket
may be suitable for use with the rotatable cutting tool provided
that the geometry of the hard cutting member corresponds to that of
the socket.
[0027] The elongate cutting tool body 32 carries an elongate
resilient retainer 52. Resilient retainer 52 presents an axial
forward end 54 and an axial rearward and 56. Resilient retainer 52
contains a longitudinal slit 58 along the entire longitudinal
length thereof. The presence of the slit 58 provides a radial
resiliency to the resilient retainer 52. Although not directly
shown, retainer 52 includes a radially inward projection that is
received within the groove 42 so as to assist with the retention of
the retainer on the shank of the rotatable cutting tool.
[0028] A generally circular washer 60 (see solid line
illustration), which has a collar 62 extending in an axial rearward
direction, surrounds and radially compresses the resilient retainer
52. Although not illustrated, washer 60 contains a central
aperture. Washer 60 as illustrated by solid lines is in a condition
prior to the insertion of the rotatable cutting tool 30 into the
bore of a block or holder. Upon the insertion of the rotatable
cutting tool 30 into the bore of a block or holder, the washer 60
is forced in an axial forward direction along the surface of the
resilient retainer 52 until it abuts against the rearward surface
of the enlarged head portion 38.
[0029] Rotatable cutting tool 30 further includes a hard cutting
member generally designated as 70 affixed by brazing within socket
44 at the axial forward end 34 of the cutting tool body 32. Grades
of cemented (cobalt) tungsten carbide suitable for use herein
include those disclosed in U.S. Pat. No. 4,859,543 to Greenfield
and U.S. Pat. No. 6,197,084 to Smith.
[0030] FIG. 2 shows the hard cutting member 70 brazed into the
socket 44 wherein there is a braze joint 68 between the hard
cutting member 70 and the surfaces that define the socket 44.
Dimension "B" represents the axial length of hard cutting member 70
axially forward of the axial forward end 34 of the cutting tool
body 32 when the hard cutting member 70 is affixed within the
socket 44 of the cutting tool body 32.
[0031] Still referring to FIG. 2 and to FIG. 3, hard cutting member
70 includes an axial forward end 72 and an axial rearward end 74,
which is flat has a has plurality of spacer bumps 76 that project
from the rearward end 74. Hard cutting member 70 includes a
functional portion shown by bracket 80. Functional portion 80 has a
transverse starting dimension equal to "C". Hard cutting member 70
further has a base portion 86, which has a transverse base
dimension "D".
[0032] Referring to FIG. 4, there is shown a second embodiment of
the hard cutting member generally designated as 90. Hard cutting
member 90 includes an axial forward end 92 and an axial rearward
end 94, which is flat has a has plurality of spacer bumps 96 that
project from the rearward end 94. Hard cutting member 90 includes a
functional portion shown by bracket 100. Functional portion 100 has
a transverse starting dimension equal to "C'". Hard cutting member
90 further has a base portion 98, which has a transverse base
dimension "D".
[0033] Referring to FIG. 5, there is shown a third embodiment of
the hard cutting member generally designated as 110. Hard cutting
member 110 includes an axial forward end 112 and an axial rearward
end 114, which is flat has a has plurality of spacer bumps 116 that
project from the rearward end 114. Hard cutting member 110 includes
a functional portion shown by bracket 120. Functional portion 120
has a transverse starting dimension equal to "C''". Hard cutting
member 110 further has a base portion 118, which has a transverse
base dimension "D'".
[0034] Table I below sets forth the dimensions B-B'', C-C'' and
D-D'' of these specific embodiments.
TABLE-US-00001 TABLE I Specific Dimensions (in millimeters) for the
First, second and Third Embodiments Dimension Dimension Dimension
Ratio of Embodiment B/B'/B'' (mm) C/C'/C'' (mm) D/D'/D'' (mm) C:D
First 14.1 8.54 18.75 0.455 Second 14.46 8.54 18.75 0.455 Third
14.46 8.54 18.75 0.455
[0035] Table II below sets forth the dimensions (in millimeters) of
various specific embodiments of the hard cutting members.
TABLE-US-00002 TABLE II Dimensions for the Specific Embodiments
Hard Cutting Members Starting Ratio of the Starting Diameter of
Diameter of Diameter of Functional Functional the Base Portion to
the Diameter Embodiment Portion (mm) Portion (mm) of the Base
Portion A 8.0 19 0.42 B 8.2 19 0.43 C 8.16 18.87 0.432 D 8.4 19
0.44 E 8.6 19 0.45 F 8.54 18.75 0.455 G 8.7 19 0.46 H 8.9 19 0.47 I
9.0 19 0.474 J 8.92 18.61 0.479
[0036] There should be an appreciation that in one sense, the ratio
of the starting transverse functional dimension to the maximum
transverse base dimension ranging between equal to 0.42 and less
than 0.48. In one range, the ratio of the starting diameter of the
functional portion to the diameter of the base portion varies
between 0.42 and 0.479. In a narrower range, the ratio of the
starting diameter of the functional portion to the diameter of the
base portion varies between 0.43 and 0.455. In a still narrower
range, the ratio of the starting diameter of the functional portion
to the diameter of the base portion varies between 0.432 and 0.45.
A mid-point of the ratio of the starting diameter of the functional
portion to the diameter of the base portion is equal to 0.44.
[0037] There should be an appreciation that the smaller ratio
provides for a narrower or smaller axial forward portion of the
hard cutting member. By doing so, the hard cutting member
experiences less resistance. By experiencing less resistance, less
power or energy is needed to drive the rotatable cutting tool
through the strata.
[0038] It thus becomes apparent that the present invention provides
an improved rotatable cutting tool, which is rotatably carried by
an individual block or holder of a rotatable drum of a cutting
machine (e.g., a road planing machine), wherein the hard cutting
insert does not contain an amount of useful cemented tungsten
carbide at the time the steel cutting tool body reaches an end of
useful life condition.
[0039] The patents and other documents identified herein are hereby
incorporated by reference herein. Other embodiments of the
invention will be apparent to those skilled in the art from a
consideration of the specification or a practice of the invention
disclosed herein. It is intended that the specification and samples
are illustrative only and are not intended to be limiting on the
scope of the invention. The true scope and spirit of the invention
is indicated by the following claims.
* * * * *