U.S. patent number RE29,900 [Application Number 05/807,026] was granted by the patent office on 1979-02-06 for pick-type mining bit with support block having rotatable seat.
This patent grant is currently assigned to Kennametal Inc.. Invention is credited to Thomas B. Kniff, deceased.
United States Patent |
RE29,900 |
Kniff, deceased |
February 6, 1979 |
Pick-type mining bit with support block having rotatable seat
Abstract
A pick type mining bit with a cylindrical shank has a support
block with a bore and a hard insert detachably and rotatably
mounted in the bore. The insert has a bore for rotatably receiving
the shank of the bit. The bit has a cylindrical working end
projecting from the support block which tapers in at the tip and
has a hard insert mounted in the tip. .Iadd .
Inventors: |
Kniff, deceased; Thomas B.
(late of Bedford, PA) |
Assignee: |
Kennametal Inc. (Latrobe,
PA)
|
Family
ID: |
27115366 |
Appl.
No.: |
05/807,026 |
Filed: |
June 16, 1977 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
751094 |
Aug 1968 |
03499685 |
Mar 10, 1970 |
|
|
Current U.S.
Class: |
299/104;
175/354 |
Current CPC
Class: |
E21C
35/197 (20130101) |
Current International
Class: |
E21C
35/00 (20060101); E21C 35/197 (20060101); E21C
013/02 (); E21C 035/18 () |
Field of
Search: |
;299/86,92,91
;175/354 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Purser; Ernest R.
Attorney, Agent or Firm: Burns; Lawrence R.
Claims
What is claimed is: .[.1. In combination; a none rotatable support
block having a bore, a sleeve of hard wear resistant material
rotatably mounted in said bore, first means retaining said sleeve
in said bore while permitting rotation of the sleeve in the bore, a
pick type bit having a cylindrical shank at one end and tapering in
at the other end to a point, said shank being receivable in one end
of said sleeve and being rotatable therein, second means detachably
retaining said shank in said sleeve while permitting rotation of
the shank in the sleeve whereby rotation of said bit can occur
during working either with or without rotation of said sleeve, and
said sleeve and support block having interengaging shoulders
thereon for sustaining axial thrusts imposed on said sleeve by said
bit during working operations, the said shoulder on said sleeve
facing away from the said one end of the sleeve..]. .[.2. The
combination according to claim 1 wherein said bore in said support
block has a larger end part nearest the bit and a smaller end part
remote from the bit, and the said shoulder on the block is at the
juncture of said parts of said bore, and said sleeve has a larger
end part nearest the bit and a smaller end part remote from the
bit, rotatably fitting the larger and smaller end parts
respectively of said bore, the shoulder on the sleeve being formed
at the
juncture of the respective end parts thereof..]. 3. The combination
according to claim .[.2.]. .Iadd.19 .Iaddend.in which said
shoulders taper
outwardly toward the bit end of said sleeve. 4. The combination
according to claim 3 in which the smaller end part of said sleeve
projects beyond said block and said first means is mounted on the
projecting portion of
said smaller end part of the sleeve outside said block. 5. The
combination according to claim 3 in which said bit comprises a
flared seat at the juncture of the shank of the bit with the other
end of the bit, said
sleeve having a flared region engaged by said seat. 6. The
combination according to claim 4 in which said sleeve has an
integral groove past which said shank extends when the bit is
mounted in the sleeve, and keeper means engaging the shank and
groove and releasably retaining the shank in
the sleeve. 7. The combination according to claim 6 in which said
keeper means is resilient so that the bit can be pried out of the
sleeve and
forced into the sleeve. 8. The combination according to claim 7 in
which said shank has an annular recess and said keeper means is
mounted in the
recess and is captive on said shank. 9. The combination according
to claim 8 in which said keeper means is in the form of a spring
band. .Iadd. 10. The combination according to claim 19 in which
said cylindrical shank of said bit is partially axially coextensive
with the bore in said support block. .Iaddend. .Iadd. 11. The
combination according to claim 18 in which said shoulders taper
outwardly toward the bit end of said sleeve. .Iaddend..Iadd. 12.
The combination according to claim 11 in which the smaller end part
of said sleeve projects beyond said block and said first means is
mounted on the projecting portion of said smaller end part of the
sleeve outside said block. .Iaddend..Iadd. 13. The combination
according to claim 11 in which said bit comprises a flared seat at
the juncture of the shank of the bit with the other end of the bit,
said sleeve having a flared region engaged by said seat.
.Iaddend..Iadd. 14. The combination according to claim 12 in which
said sleeve has an integral groove past which said shank extends
when the bit is mounted in the sleeve, and keeper means engaging
the shank and groove and releasably retaining the shank in the
sleeve. .Iaddend..Iadd. 15. The combination according to claim 14
in which said keeper means is resilient so that the bit can be
pried out of the sleeve and forced into the sleeve. .Iaddend..Iadd.
16. The combination according to claim 15 in which said shank has
an annular recess and said keeper means is mounted in the recess
and is captive on said shank. .Iaddend..Iadd. 17. The combination
according to claim 16 in which said keeper means is in the form of
a spring band. .Iaddend. .Iadd. 18. In combination: a non-rotatable
support block having a bore; a sleeve of hard wear resistant
material rotatably mounted in said bore; and a pick type bit having
a shank rotatably receivable in one end of said sleeve; first means
retaining said sleeve in said bore while permitting rotation of the
sleeve in the bore; and second means detachably retaining said
shank in said sleeve while permitting rotation of the shank in the
sleeve so that rotation can occur both with and without rotation of
said sleeve; said bore having a larger end part nearest the bit and
a smaller end part remote from the bit; and a shoulder formed on
the block at the juncture of said parts of said bore; said sleeve
having a larger end part nearest the bit and a smaller end part
remote from the bit and a shoulder, facing away from said one end
of said sleeve, formed at the juncture of the respective end parts
of the sleeve; said sleeve rotatably fitting the larger and smaller
end parts respectively of said bore; said bit having a cylindrical
shank at one end and tapering in at the other end to a point with
said shank in said sleeve being partially axially coextensive with
said bore in said support block; cooperating elements of abutment
means between said sleeve and said bit; and said shoulders on said
sleeve and said support block interengaging one another for
sustaining axial thrusts imposed on said sleeve by said bit during
working operations. .Iadd. 19. In combination: a non-rotatable
support block having a bore; a sleeve of hard wear resistant
material rotatably mounted in said bore; and a pick type bit having
a shank rotatably receivable in one end of said sleeve; first means
retaining said sleeve in said bore while permitting rotation of the
sleeve in the bore; and second means detachably retaining said
shank in said sleeve while permitting rotation of the shank in the
sleeve so that rotation can occur both with and without rotation of
said sleeve; said bore having a larger end part nearest the bit and
a smaller end part remote from the bit; and a shoulder formed on
the block at the juncture of said parts of said bore; said sleeve
having a larger end part nearest the bit and a smaller end part
remote from the bit and a shoulder facing away from said one end of
said sleeve formed at the juncture of the respective end parts of
the sleeve; said sleeve rotatably fitting the larger and smaller
end parts respectively of said bore; said bit having a cylindrical
shank at one end and tapering in at the other end to a point and
said shoulders on said sleeve and said support block interengaging
one another for sustaining axial thrusts imposed on said sleeve by
said bit during working operations. .Iaddend.
Description
The present application is an application for reissue of U.S. Pat.
No. 3,499,685, issued Mar. 10, 1970. .Iaddend.
This invention relates to mining tools, particularly to pick type
bits for use with mining machines and to a support arrangement
therefor.
Pick type mining bits are, of course, well known and, in general,
take the form of an elongated body round in cross section and
symmetrical about a central axis with a cylindrical supporting
shank at one end and with the other end generally tapering inwardly
to a point in which is mounted a cemented carbide wear resistant
element. Such bits, it has been found, by a proper support thereof,
will rotate on their axis when properly supported. The rotation is
preferably caused by the engagement of the bit with the work and
has the advantage of distributing the wear about the periphery of
the bit or by the life of the bit is substantially lengthened
while, furthermore, the point end of the bit remains sharp.
The portion of the bit immediate rearwardly of the point is usually
conical and as the bit is used and rotates in use, the body of the
bit adjacent the hard cemented carbide insert wears away so that
the carbide insert remains exposed. A bit of this nature has the
disadvantage that as the point end of the bit wears away in use,
the area of the body surrounding the carbide insert increases and
this places a greater work load on the machine driving the bit and
can also interfere with maintaining the proper exposure of the
carbide insert.
In connection with the rotation of the bit in the holder, the bit
and holder comprise cooperating inclined or conical shoulder areas,
and these shoulder areas are subjected to substantial loads as the
bit is used. Because of the loads involved, the shoulders sometimes
wear relatively rapidly. With the bit itself, relatively rapid wear
of the shoulder is not particularly important because, at worst, it
will not wear away nearly as rapidly as the working point end
thereof. The support for the bit, however, is in the form of a
block which is usually welded in place on the drive machine and
rapid wear of the shoulder on the block is a serious problem
because the block is normally expected to remain in good condition
for the life of several bits.
With the foregoing in mind, it is a primary object of the present
invention to provide a pick type mining bit and a support block
therefor which overcomes the disadvantages referred to above.
Another object of this invention is the provision of a pick type
mining bit having improved operating characteristics.
Still another object of this invention is the provision of a
supporting arrangement for a rotatable pick type mining bit in
which the wear of the supporting arrangement is maintained at a
minimum.
The foregoing objects, as well as still other objects and
advantages of the present invention, will become more apparent upon
reference to the following detailed specification taken in
connection with the accompanying drawings in which:
FIG. 1 is an exploded side elevational view showing a bit
arrangement and support therefor according to the present
invention, and
FIG. 2 is a view partly in section looking at the bit and
supporting arrangement from the side and showing the bit assembled
with the supporting arrangement.
Referring to the drawings somewhat more in detail, in FIGS. 1 and 2
it will be seen that the arrangement comprises a support block 10,
which may be a forging, and which is adapted for being secured to a
support member as by welding. It will be noted that the block 10
comprises a curved lower portion 12 which adapts the block for
welding to the surface of a drum or the like, but it will be
understood that the block could be shaped for mounting on a chain
length or any other suitable supporting and driving device.
Block 10 has a shoulder bore 14 extending therethrough with a
larger forward portion 14a and a smaller rearward portion 14b which
are interconnected by a forwardly facing inclined seat region 16.
Seated in bore 14 is a hardened metal sleeve 18 comprising a larger
forward portion 18a which rotatably fits in bore portion 14a, and a
smaller diameter rearward portion 18b which rotatably fits in bore
portion 14b. Portion 18b extends out the back of the block and has
a groove 20 therein in which snap rings 22 are mounted.
Joining portions 18a and 18b is an inclined region 24 which fits
against inclined region 16 of bore 14. The arrangement is such that
sleeve 18 is held in block 10 with a slight degree only of freedom
of axial movement therein so that the sleeve is relatively freely
rotatable in the block.
Sleeve 18 has a central bore 30 which at the forward end has a
flared out seat 32. Spaced rearwardly from seat 32 in bore 30 in an
annular recess or undercut or groove 34.
The arrangement described above is the support for the bit to be
described and is characterized in the sleeve 18 which reduces the
wear on the block and which is itself readily replaceable when
excessive wear thereof occurs.
Referring now to the bit, this will be seen to comprise a rearward
cylindrical shank 40 having at its one end a flared out seat region
32 adapted for engagement with seat region .[.32.]. .Iadd.42
.Iaddend.at the forward end of bore 30. .Iadd.These flared out seat
regions form cooperating elements of abutment means between the bit
and sleeve 18. .Iaddend.Following seat region 42, the bit body has
an annular groove 44 therein which is for the purpose of receiving
a tool for removing the bit from the support when it is to be
changed. Forwardly of groove 44 the bit body tapers inwardly
rapidly as shown at 46 and then has a substantially cylindrical
region 48 which may be of about the same diameter as shank 40. Near
the forward end of the bit, there is a frusto-conical portion 50.
An axial bore 52 is provided extending inwardly into the
frusto-conical end of the bit and seated in bore 52 and preferably
retained therein by brazing is a tip element 54 of a hard material,
preferably cemented tungsten carbide. Tip element 54 has a pointed
end 56 which is a substantial continuation of the inclined wall of
frusto-conical portion 50.
Shank portion 40 has an annular groove 60 formed therein in which
is seated a split spring band 62 having dimples or protuberances 64
therein distributed about the periphery therefo. The groove 60 and
the protuberances 64 are so located along the shank 40 that when
the bit is pressed into bore 30 into its FIG. 2 position, the said
protuberances 64 will snap into annular groove 34 in bore 30 so as
to retain the bit in assembled relation with sleeve 18. The
resilient keeper arrangement is illustrated in the copending Engle,
et al., application Ser. No. 479,094 filed Aug. 12, 1965, and
assigned to the same assignee as the present application. The
keeper in the form of a spring band 62 will yield inwardly in
groove 60 so as to permit the bit to be pushed into bore 30 and
will then snap outwardly when the bit is completely seated in the
bore. The keeper firmly retains the bit in sleeve 18 and permits a
slight amount of axial movement of the bit in bore 30 so that the
bit is not locked against seat region 32 and is freely rotatable in
bore 30.
Inasmuch as the bit can rotate in bore 30 and sleeve 18 can rotate
in block 10, there will always be rotation of the bit whether this
occurs between the bit and sleeve 18 and block 10 or at both
places. The possibility of the bit binding and failing to rotate
thus becomes remote. Furthermore, the wear on the block is
substantially reduced over the wear that takes place on the block
which directly supports the bit and in which a bit rotates. It will
be appreciated that the bit can be replaced as often as necessary
while block 10 will have greatly increased wearing characteristics
and will not have to be replaced nearly as often as heretofore has
been the case. Rather, the principal wear areas will be on the bit,
and sleeve 18 will normally outwear many bits and can itself easily
be replaced.
The particular configuration of the bit illustrated herein is of
importance because the point end of the bit as it wears and rotates
in use will be worn off substantially at the angle of the inclined
outer surface of frusto-conical portion 50. It will be seen that
the bit can wear down until the carbide tip is used up before the
diameter of the body material surrounding the tip element commences
to increase. The driving machine for the bit will thus not be
subjected to increased load as the bit wears and the important
characteristic of a pick type bit of removing material by a sort of
exploding action is not interfered with and the quality of the
material removed by the bit with respect to the content of lines
and the particle size, does not change as the bit wears down in
use.
* * * * *