U.S. patent application number 13/036124 was filed with the patent office on 2012-03-01 for retainer for rotatable cutting bit.
This patent application is currently assigned to Kennametal Inc.. Invention is credited to Eric Paul Helsel, Cary Douglas Ritchey.
Application Number | 20120049608 13/036124 |
Document ID | / |
Family ID | 45442012 |
Filed Date | 2012-03-01 |
United States Patent
Application |
20120049608 |
Kind Code |
A1 |
Ritchey; Cary Douglas ; et
al. |
March 1, 2012 |
RETAINER FOR ROTATABLE CUTTING BIT
Abstract
A retainer for mounting and retaining a rotatable cutting tool
or bit in a block bore. The cutting tool contains an annular
channel. The retainer has an unstressed diameter greater than the
diameter of the bore so that when the cutting tool is inserted into
the bore, the retainer expands against the bore so as to be held
therein along with the cutting tool. The retainer comprises a
cylindrical sleeve having an engaging member extending
circumferentially around the sleeve and having a constant cross
section shape which projects into the annular channel of the
cutting tool and which annular channel has an inward rectangular
surface corresponding to the inward engaging member of the retainer
for receiving and retaining the retainer to the cutting tool.
Inventors: |
Ritchey; Cary Douglas;
(Roaring Spring, PA) ; Helsel; Eric Paul; (New
Enterprise, PA) |
Assignee: |
Kennametal Inc.
Latrobe
PA
|
Family ID: |
45442012 |
Appl. No.: |
13/036124 |
Filed: |
February 28, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61317719 |
Mar 26, 2010 |
|
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Current U.S.
Class: |
299/104 |
Current CPC
Class: |
E21C 35/197
20130101 |
Class at
Publication: |
299/104 |
International
Class: |
E21C 35/197 20060101
E21C035/197 |
Claims
1. A cutting tool for mounting in the bore of a block, the cutting
tool, comprising: an elongated body generally symmetrical about a
longitudinal axis having forward and rearward portions, the forward
portion terminating in a front end at which there is a cutting tip,
the rearward portion being of a generally constant diameter and
terminating in a rear end; the rearward portion containing an
annular channel adjacent the rear end; a resilient retainer
surrounding substantially the rearward portion, the retainer
comprising a cylindrical sleeve being axially split along the
entire length thereof, the sleeve having opposite front and rear
ends, and having an inward engaging member received within the
annular channel so that the elongated body and retainer are
retained together; and wherein the inward engaging member of the
resilient retainer comprises a constant cross sectional shape
extending circumferentially around the cylindrical sleeve.
2. The cutting tool of claim 1, wherein the annular channel has
generally the same cross sectional shape as the inward engaging
member.
3. The cutting tool of claim 1, wherein the inward engaging member
has a generally rectangular cross sectional shape.
4. The cutting tool of claim 3, wherein the annular channel of the
rearward portion of the elongated body of the cutting tool has an
inward rectangular surface corresponding to the generally
rectangular cross sectional shape of the inward engaging member of
the cylindrical sleeve.
5. The cutting tool of claim 1, wherein the inward engaging member
of the cylindrical sleeve is an annular radial projection extending
around the circumferential inner surface of the cylindrical
sleeve.
6. The cutting tool of claim 1, wherein the cylindrical sleeve and
the inward engaging member of the cylindrical sleeve form a T-shape
configuration along the longitudinal axis of the cylindrical
sleeve.
7. The cutting tool of claim 1, wherein the retainer has an
unstressed diameter greater than the diameter of the bore so that
when the cutting tool is inserted into the bore the retainer
expands against the bore so as to be held therein.
8. A resilient retainer for rotatably mounting a rotatable cutting
bit in the cylindrical bore of a block, comprising: an elongate
cylindrical sleeve being axially split along the entire length
thereof, the sleeve having opposite front and rear ends, an inward
engaging member extending substantially around an inner periphery
thereof, wherein the inward engaging member has a constant cross
sectional shape.
9. The retainer of claim 8, wherein the inward engaging member has
a generally rectangular cross sectional shape.
10. The retainer of claim 8, wherein the inward engaging member of
the cylindrical sleeve is an annular radial projection extending
around the circumferential inner surface of the cylindrical
sleeve.
11. The retainer of claim 8, wherein the cylindrical sleeve and the
inward engaging member of the cylindrical sleeve form a T-shape
configuration along the longitudinal axis of the cylindrical
sleeve.
12. A cutting tool for mounting in the bore of a block, the cutting
tool, comprising: an elongated body generally symmetrical about a
longitudinal axis having forward and rearward portions, the forward
portion terminating in a front end at which there is a cutting tip,
the rearward portion being of a generally constant diameter and
terminating in a rear end; the rearward portion containing an
annular channel adjacent the rear end; a resilient retainer
surrounding substantially the rearward portion, the retainer
comprising a cylindrical sleeve being axially split along the
entire length thereof, the sleeve having opposite front and rear
ends, and having an inward engaging member received within the
annular channel so that the elongated body and retainer are
retained together; and wherein the inward engaging member of the
resilient retainer has a generally symmetrical shape about a
central longitudinal axis thereof.
13. The cutting tool of claim 12, wherein the annular channel has
generally the same cross sectional shape as the inward engaging
member.
14. The cutting tool of claim 12, wherein the inward engaging
member has a generally rectangular cross sectional shape.
15. The cutting tool of claim 14, wherein the annular channel of
the rearward portion of the elongated body of the cutting tool has
an inward rectangular surface corresponding to the generally
rectangular cross sectional shape of the inward engaging member of
the cylindrical sleeve.
16. The cutting tool of claim 12, wherein the central longitudinal
axis of the inward engaging member extends generally parallel to a
wall of the cylindrical sleeve.
17. A resilient retainer for rotatably mounting a rotatable cutting
bit in the cylindrical bore of a block, comprising: an elongate
cylindrical sleeve being axially split along the entire length
thereof, the sleeve having opposite front and rear ends, an inward
engaging member extending substantially around an inner periphery
thereof, wherein the inward engaging member has a generally
symmetrical shape about a central longitudinal axis thereof.
18. The retainer of claim 17, wherein the inward engaging member
has a generally rectangular cross sectional shape.
19. The retainer of claim 17, wherein the central longitudinal axis
of the inward engaging member extends generally parallel to a
longitudinal axis of the cylindrical sleeve.
20. The retainer of claim 17, wherein the cylindrical sleeve and
the inward engaging member of the cylindrical sleeve form a T-shape
configuration along the longitudinal axis of the cylindrical
sleeve.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/317,719 filed Mar. 26, 2010, which
is fully incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention pertains to an earth working, mining, or
construction bit, and more particularly, to a retainer wear sleeve
for holding a rotatable cutting bit in a mounting block that is
affixed to a movable member.
BACKGROUND
[0003] Rotatable cutting bits held within a mounting block affixed
to a movable member, such as a mining wheel or road planning drum,
are utilized to perform various excavating operations, which
include applications relating to the removal of minerals as well as
applications relating to road planning, trenching, concrete cutting
and other construction applications.
[0004] Prior art cutting bits have utilized an enlarged diameter or
sharply stepped rearward portion of the bit as an abutment to
retain a cylindrical retainer or clip captive on the bit. In
operation of the prior art bits and retainers, the rearward portion
of the bit contacts the cylindrical wall of the bore so that wear
on certain portions of the bore occurs as the bit rotates in the
mounting block. U.S. Pat. No. 4,850,649 to Wayne H. Beach, et al.
provides a retainer wear sleeve which protects the bore of the
block from wear due to contact with the shank of the cutting bit
during operation. Such a retainer wear sleeve increases the life of
the block since contact between the shank and the bore of the block
is reduced.
[0005] During the cutting operation, a large volume of particulate
materials are generated. These particulates tend to infiltrate the
bore of the block-bit assembly, and collect in the volume between
the rear shank and the retainer wear sleeve. The prior art cutting
bits having an enlarged diameter or sharply stepped rearward
portion have trapped these contaminates, and impaired the ability
of the bit either to rotate in the bore of or to be efficiently
removed from the block. The retainer wear sleeve of the above
mentioned U.S. Pat. No. 4,850,649 to Wayne H. Beach, et al. reduces
the tendency of particulate material being trapped between the
sleeve and the shank. This '649 patent discloses a retainer wear
sleeve either having projecting dimples, an annular projection or
equi-spaced circumferential projections which are received within
an annular channel of the cutting bit for retaining the sleeve to
the shank of the bit.
[0006] There is a need to provide a retainer for a rotatable
cutting bit which is sturdier than known retainer wear sleeves.
[0007] There is a further need to provide a retainer for a
rotatable cutting bit that comprises an engaging member projecting
into an annular channel of the cutting bit and which engaging
member has a cross-sectional area that is greater than the engaging
devices of known retainer wear sleeves.
SUMMARY
[0008] An aspect of the present invention is to provide a retainer
for a rotatable cutting bit for mounting and retaining the
rotatable cutting bit in a bore of a block that is affixed to a
movable member. In one aspect, the invention comprises a retainer
and a cutting tool or bit for mounting in the bore of the block
wherein the cutting tool comprises an elongated bit body generally
symmetrical about a longitudinal axis. The elongated body has
forward and rearward portions wherein the forward portion
terminates in a front end at which there is a cutting tip and the
rearward portion is of a generally constant diameter and terminates
in a rear end. The rearward portion contains an annular channel or
groove adjacent the rear end thereof. A resilient retainer
comprising a wear sleeve surrounds substantially the peripheral
rearward shank portion and extends rearwardly past the rear end and
has an inward engaging member received within the annular channel
so that the elongated body and retainer are retained together. The
retainer has an unstressed diameter greater than the diameter of
the bore so that when the cutting tool is inserted into the bore,
the retainer expands against the bore so as to be held therein. In
one aspect, the retainer comprises an inward engaging member
comprising a constant cross-sectional shape. In another aspect, the
inward engaging member has a generally symmetrical shape about a
central longitudinal axis thereof. In another aspect, the inward
engaging member may have a generally rectangular cross-sectional
shape. The annular channel of the cutting bit has an inward surface
which corresponds in shape to the inward engaging member, e.g.
generally rectangular, of the retainer so that the inward engaging
member is received in the annular channel when the retainer is
mounted around the shank of the cutting bit, resulting in the
retainer and cutting bit being retained together.
[0009] These and various other features and advantages will be
apparent from the following drawings and detailed description.
DRAWINGS
[0010] FIG. 1 is a side view of a cutting bit-block assembly
wherein the cutting bit is inserted into the block and the block is
affixed to a movable member.
[0011] FIG. 2 is the cutting body of FIG. 1 and a retainer of the
invention.
[0012] FIG. 3 is the retainer of the invention mounted onto the
shank of a cutting tool.
[0013] FIG. 4 is a cross-sectional view of the retainer of FIG.
2.
[0014] FIG. 5 is an end view of the retainer of FIG. 4.
[0015] FIG. 6 is a sketch of a cutting body and a retainer of the
invention similar to that of FIG. 2.
[0016] FIG. 7 is a perspective view of the cylindrical sleeve of
the retainer of FIG. 6.
[0017] FIG. 8 is an open flat cross sectional view of the
cylindrical sleeve of FIG. 7.
DETAILED DESCRIPTION
[0018] Referring to the drawings, there is illustrated in FIG. 1 a
cutting assembly generally designated as 10 which is mounted to a
rotatable or movable member 12. Although not intended to be
limiting, the rotatable or movable member may comprise a mining
wheel, a road planning drum, a bucket blade, a grader blade or the
like. The cutting assembly 10 includes a block 14 having a front
face 16, a rear face 18, and a mounting face 20. As disclosed in
the above discussed U.S. Pat. No. 4,850,649, which is incorporated
herein by reference, block 14 includes a generally cylindrical bore
having a frusto-conically shaped seating surface adjacent the front
face 16 thereof. As can be appreciated from FIG. 1, the block 14 is
affixed at the mounting face 20 to the rotatable member 12 such as
by welding or the like.
[0019] Referring to FIGS. 1-3, cutting assembly 10 further includes
a rotatable or movable cutting tool or bit generally designated as
30. Cutting bit 30 includes an elongated steel body 32 having
integral forward and rearward portions 34 and 36, respectively. An
annular frusto-conically shaped shoulder 38 joins the forward and
rearward portions. Body 32 further includes an annular shoulder 40
positioned forwardly of annular shoulder 38.
[0020] Forward portion 34 includes a flat front face 42 having a
socket (not shown) contained therein in which a cutting tip 44 is
affixed such as by brazing. Cutting tip 44 is made from a hard
material such as a cemented tungsten carbide.
[0021] The rearward portion 36 of steel body 32 terminates in a
flat rear end 46 and contains an annular channel 50 positioned
forwardly of the flat rear end 46. A constant diameter cylindrical
portion 52 then joins the annular channel 50 with the annular
shoulder 38.
[0022] As illustrated in FIGS. 2 and 3, a retainer generally
designated as 54 surrounds substantially the rearward portion 36 of
the cutting bit body 32. The retainer 54 serves two basic purposes.
The first is to retain the bit body 32 in the block 14, and the
second is to protect the block 14 from wear by functioning as a
wear sleeve between the bit body 32 and the block 14.
[0023] Referring to FIGS. 4, 6, and 7, retainer 54 comprises an
elongate cylindrical sleeve 56 having a forward portion 58 and a
rearward portion 60. The forward portion 58 terminates in a
generally circularly-shaped front edge 62 and the rearward portion
60 terminates in a generally circularly-shaped rearward edge
64.
[0024] The forward portion 58 of cylindrical sleeve 56 contains an
inward engaging member 66 positioned forwardly of the juncture
between the forward and rearward portions 58, 60 of sleeve 56. In
one aspect, the inward engaging member 66 may have, for example, a
generally rectangular cross-sectional shape as shown in the
Figures. However, it will be appreciated that the inward engaging
member 66 may have other shapes as well in accordance with the
invention. As can be appreciated from FIGS. 2 and 3, the retainer
54 is positioned relative to the cutting bit body 32 so as to
surround the rearward portion 36 thereof whereby the inward
engaging member 66 is received within the annular channel 50 of
cylindrical portion 52 of body bit 32. In one aspect, the annular
channel 50 has an inward surface which corresponds in shape to the
inward engaging member 66, e.g. generally rectangular, so that the
inward engaging member 66 is received in the annular channel
50.
[0025] The diameter of the forward portion 58 and rearward portion
60 of sleeve 56 of retainer 54 in an unstressed condition is larger
than the diameter of the bore of block 14. Consequently, when the
assembly of the cutting bit body 32 and the retainer 54 is inserted
into the bore of the block 14, the diameter of the forward portion
58 and the rearward portion 60 of the retainer 54 is radially
compressed whereby when inside the bore, the retainer 54 expands
against the bore so as to be securely held therein. Inward engaging
member 66 of retainer 54 is received within annular channel or
groove 50 so as to retain the cutting bit body 32 and retainer 54
together. The dimensioning of inward engaging member 66 relative to
the annular channel or groove 50 and the cylindrical sleeve 56
itself relative to the rearward portion 36 of the cutting bit body
32 are as such that the cutting bit 30 is free to rotate relative
to the retainer 54 and the block 14 when the cutting bit-retainer
assembly is inserted into the bore of block 14. As can be
appreciated, the cutting bit body 32 is rotatably retained by the
retainer 54 which is securely held in the bore of block 14. The end
result being that the bit is rotatably mounted within the block
14.
[0026] FIG. 5 shows that retainer 54 is a split ring wherein the
longitudinal edges 70 and 72 of sleeve 56 of retainer 54 form an
opening defined by the edges 70 and 72. As best shown in FIG. 6,
retainer 54 is mounted around body bit 32 such that the inward
engaging member 66 enters and is received in annular channel or
groove 50. FIG. 7 illustrates that the inward engaging member 66 of
the cylindrical sleeve 56 is an annular radial projection extending
circumferentially around the inner surface 78 of cylindrical sleeve
56.
[0027] As particularly shown in FIGS. 4, 6 and 7, the inward
engaging member 66 has a constant cross-sectional shape. In other
words, the shape of the inward engaging member 66 remains the same
from where it contacts the inner surface 78 of the cylindrical
sleeve 56 to its inner most portion 67 that extends inwardly toward
the center portion of the sleeve 56. In addition, the shape of the
inward engaging member may be characterized as generally
symmetrical about a longitudinal central axis CL thereof (see FIG.
7). In one aspect, the axis CL extends generally parallel to the
vertical wall 57 of the sleeve 56.
[0028] As shown in FIG. 8, the cylindrical sleeve 56 comprises a
T-shape configuration along the longitudinal axis of the
cylindrical sleeve 56. It is to be appreciated that retainer 54 is
made of a hard material, for example, steel.
[0029] As best shown in FIGS. 6, 7 and 8, the inward engaging
member 66 of cylindrical sleeve 56 generally has a rectangular
cross section and as shown particularly in FIG. 6, annular channel
50 of the shank of body bit 32 generally has a rectangular
cross-sectional surface 68 that corresponds to the rectangular
cross section of engaging member 66 of cylindrical sleeve 56 so
that when retainer 56 is positioned around body bit 32, the inward
engaging member 66 enters into the annular channel 50 of body bit
32. This structure for retainer 52 is advantageous in that more
surface area is provided thereby resulting in a more sturdy
structure for retainer 52.
[0030] The implementation described above and other implementations
are within the scope of the described invention and the following
claims.
* * * * *