U.S. patent number RE38,151 [Application Number 09/933,234] was granted by the patent office on 2003-06-24 for rotatable cutting bit.
This patent grant is currently assigned to Kennametal Inc.. Invention is credited to Joe Penkunas, Neil Portnoff.
United States Patent |
RE38,151 |
Penkunas , et al. |
June 24, 2003 |
Rotatable cutting bit
Abstract
A rotatable cutting insert of improved geometry having a shank
depending from a head portion and having a hard insert mounted
therein, includes an insert having a conically shaped tip section,
a base section contiguous with a first intermediate section, a
second intermediate section contiguous with both tip and first
intermediate section, and where the diameter of the second
intermediate section is equal to the maximum diameter of the tip
but is smaller than the diameter of the base section.
Inventors: |
Penkunas; Joe (Wake Forest,
NC), Portnoff; Neil (Towanda, PA) |
Assignee: |
Kennametal Inc. (Latrobe,
PA)
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Family
ID: |
25042489 |
Appl.
No.: |
09/933,234 |
Filed: |
August 20, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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756210 |
Jul 18, 1985 |
4725099 |
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Reissue of: |
074210 |
Jul 16, 1987 |
04865392 |
Sep 12, 1989 |
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Current U.S.
Class: |
299/111;
175/426 |
Current CPC
Class: |
E21C
35/183 (20130101); E21C 35/188 (20200501); E21C
35/1837 (20200501) |
Current International
Class: |
E21C
35/00 (20060101); E21C 35/183 (20060101); E21C
35/18 (20060101); E21C 035/18 () |
Field of
Search: |
;299/111,113,110,79.1
;175/426,428 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1275499 |
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Apr 1969 |
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DE |
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2442146 |
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Mar 1976 |
|
DE |
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2644992 |
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Apr 1978 |
|
DE |
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2820642 |
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Nov 1978 |
|
DE |
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2821673 |
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Apr 1980 |
|
DE |
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2846744 |
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Apr 1980 |
|
DE |
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1350451 |
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Mar 1963 |
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FR |
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1110495 |
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Apr 1968 |
|
GB |
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1112446 |
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May 1968 |
|
GB |
|
1294717 |
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Nov 1972 |
|
GB |
|
2041289 |
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Sep 1980 |
|
GB |
|
1601470 |
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Oct 1981 |
|
GB |
|
316835 |
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Oct 1971 |
|
SU |
|
468994 |
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Jul 1975 |
|
SU |
|
646047 |
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Feb 1979 |
|
SU |
|
899916 |
|
Jan 1982 |
|
SU |
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Other References
American Mine Tool Drawing T104 23 (Mar. 29, 1983) Long Rock Tip.
.
Kennametal Catalog for "Carbide Tools" (1980) B80-43 (10) LO. .
General Electric Drawing for CCT-765-CB Tip (Mar. 27, 1979). .
Multi-Metals Drawing C-14455-7 (Sep. 5, 1973). .
American Mine Tool "Competitive Evaluation Report" (Jun. 29, 1982)
by R.W. Ojanen. .
"Rock cutting experiments with point attack tools," Collier
Guardian Coal International Apr. 1980 Pp. 47, 49-50. .
Mining Journal, Apr. 2, 1965 "Cap Tip For Picks". .
Advertisement for Mining Supplies Ltd in Colliery Guardian, Oct. 4,
1962. .
American Mine Tool Drawing T-104-13 (Nov. 30, 1982). .
American Mine Tool Drawing AM722M (Oct. 13, 1982). .
American Mine Tool Drawing SC-12 (May 8, 1982)..
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Primary Examiner: Shackelford; Heather
Assistant Examiner: Kreck; John
Attorney, Agent or Firm: Weldon; Kevin P.
Parent Case Text
This is a continuation of co-pending application serial no. 756,210
filed on 7/18/85 now U.S. Pat. No. 4,725,099.
Claims
I claim:
1. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, said sections
comprising a base section, a tip section, a first intermediate
section contiguous with said base, a second intermediate section of
uniform diameter contiguous with said first intermediate and tip
sections, .Iadd.said second intermediate section extends forwardly
along the longitudinal axis from the junction with the first
intermediate section to the tip section a distance of about 0.02 to
about 0.05 inches, .Iaddend.said base being fixedly mounted in said
socket and having a first diameter, said tip section being
conically shaped and having a maximum second diameter, said first
intermediate section having a maximum third diameter, said second
intermediate section having a fourth diameter equal to said maximum
second diameter, said second and third diameters each being less
than said first diameter, said first intermediate section has a
frusto-conical shape and angles outwardly from the junction with
said second intermediate section to the junction with said base
section, said first intermediate section at said base forming a
fillet at the junction thereof whereby said base forms a shoulder
with said first intermediate section said insert is fixedly held to
said head portion by brazing.
2. A rotatable cutting bit according to claim 1 wherein said tip
section tapers outwardly at an included angle of from about 83
degrees to about 93 degrees.
3. A rotatable cutting bit according to claim 2 wherein said first
intermediate section extends forwardly along the longitudinal axis
from said base section to said second intermediate section a
distance of from about 0.22 to about 0.28 inches.
4. A rotatable cutting bit according to claim 3 wherein said second
intermediate section has a cylindrical shape .[.and extends
forwardly along the longitudinal axis from the junction with said
first intermediate section to the tip section a distance of about
0.02 to about 0.05 inches.]. .
5. A rotatable cutting bit according to claim 4 wherein said base
section extends forwardly along the longitudinal axis a distance of
from about 0.05 to about 0.11 inches.
6. A rotatable cutting bit according to claim 5 wherein said first
diameter is from about 0.60 to about 0.66 inches.
7. A rotatable cutting bit according to claim 6 wherein said second
diameter is from about 0.36 to about 0.44 inches.
8. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, said sections
comprising a base section, a tip section, a first intermediate
section contiguous with said base, substantially all of said first
intermediate section projects forwardly of the forward end of said
head portion, a second intermediate section of uniform diameter
contiguous with said first intermediate and tip sections,
.Iadd.said second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance of about 0.02 to about 0.05
inches, .Iaddend.said base being fixedly mounted in said socket and
having a first diameter, said tip section being conically shaped
and having a maximum second diameter, said first intermediate
section having a maximum third diameter, said second intermediate
section having a fourth diameter equal to said maximum second
diameter, said second and third diameters each being less than said
first diameter, said first intermediate section has a
frusto-conical shape and angles outwardly from the junction with
said second intermediate section to the junction with said base
section, said first intermediate section at said base forming a
fillet at the junction thereof whereby said base forms a shoulder
with said first intermediate section said insert is fixedly held to
said head portion by brazing.
9. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, said sections
comprising a base section, a tip section, a first intermediate
section contiguous with said base, a second intermediate section of
uniform diameter contiguous with said first intermediate and tip
sections, .Iadd.said second intermediate section extends forwardly
along the longitudinal axis from the junction with the first
intermediate section to the tip section a distance of about 0.02 to
about 0.05 inches, .Iaddend.said base being fixedly mounted in said
socket and having a first diameter, said tip section being
conically shaped and having a maximum second diameter, said first
intermediate section having a maximum third diameter, said second
intermediate section having a fourth diameter equal to said maximum
second diameter, said second and third diameters each being less
than said first diameter, said first intermediate section has a
frusto-conical shape and angles outwardly from the junction with
said second intermediate section to the junction with said base
section at an included angle of from about 17 to about 23 degrees,
said first intermediate section at said base forming a fillet at
the junction thereof whereby said base forms a shoulder with said
first intermediate section said insert is fixedly held to said head
portion by brazing.
10. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, said sections
comprising a base section, a tip section, a first intermediate
section contiguous with said base, a second intermediate section of
uniform diameter contiguous with said first intermediate and tip
sections, .Iadd.said second intermediate section extends forwardly
along the longitudinal axis from the junction with the first
intermediate section to the tip section a distance of about 0.02 to
about 0.05 inches, .Iaddend.said base being fixedly mounted in said
socket and having a first diameter, said tip section being
conically shaped and having a maximum second diameter, said first
intermediate section having a maximum third diameter, said second
intermediate section having a fourth diameter equal to said maximum
second diameter, said second and third diameters each being less
than said first diameter, said first intermediate section has a
frusto-conical shape and angles outwardly from the junction with
said second intermediate section to the junction with said base
section at an included angle of from about 17 to about 23 degrees,
said first intermediate section at said base forming a fillet at
the junction thereof whereby said base forms a shoulder with said
first intermediate section said insert is fixedly held to said head
potion by brazing, said braze flowing over and around said base
section.
11. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having a coaxially aligned and integral sections, said
.[.section.]. .Iadd.sections .Iaddend.comprising a base section, a
tip section, a first intermediate section contiguous with said
base, a second intermediate section of uniform diameter contiguous
with said first intermediate and tip sections, .Iadd.said second
intermediate section extends forwardly along the longitudinal axis
from the junction with the first intermediate section to the tip
section a distance of about 0.02 to about 0.05 inches,
.Iaddend.said base being fixedly mounted in said socket and having
a first diameter of from about 0.60 to about 0.66 inches, said tip
section having a maximum second diameter being from about 0.35 to
about 0.44 inches and being conically shaped with an included angle
from about 83 degrees to about 93 degrees, said first intermediate
section having a maximum third diameter, said second intermediate
section having a maximum fourth diameter equal to said maximum
second diameter, said second and third diameters each being less
than said first diameter, said first intermediate section has a
frusto-conical shape angling outwardly from the junction with said
second intermediate section to the junction with said base section
at an included angle of about 17 to about 23 degrees, said first
intermediate section and said base forming a fillet at the junction
thereof whereby said base forms a shoulder with said intermediate
section, said insert is fixedly held to said head portion by
brazing.
12. A rotatable cutting bit according to claim 11 wherein said
first intermediate section extends forwardly along the longitudinal
axis from said base section to said second intermediate section a
distance of about 0.22 to about 0.28 inches..[.
13. A rotatable bit according to claim 12 wherein said second
intermediate section extends forwardly along the longitudinal axis
from said first intermediate section to said second section a
distance from about 0.02 to about 0.05 inches..].
14. A rotatable cutting bit according to claim .[.13.]. .Iadd.12
.Iaddend.wherein said base section extends forwardly along the
longitudinal axis a distance of from about 0.05 to about 0.11
inches.
15. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having a coaxially aligned and integral sections, said
.[.section.]. .Iadd.sections .Iaddend.comprising a base section, a
tip section, a first intermediate section contiguous with said
base, a second intermediate section of uniform diameter contiguous
with said first intermediate and tip sections, .Iadd.said second
intermediate section extends forwardly along the longitudinal axis
from the junction with the first intermediate section to the tip
section a distance of about 0.02 to about 0.05 inches,
.Iaddend.said base being fixedly mounted in said socket and having
a first diameter of from about 0.60 to about 0.66 inches, said tip
section having a maximum second diameter being from about 0.36 to
about 0.44 inches and being conically shaped with an included angle
from about 83 degrees to about 93 degrees, said first intermediate
section having a maximum third diameter, said second intermediate
section having a maximum fourth diameter equal to said maximum
second diameter, said second and third diameters each being less
than said first diameter, said first intermediate section has a
frusto-conical shape angling outwardly from the junction with said
second intermediate section to the junction with said base section
at an included angle of about 17 to about 23 degrees, said first
intermediate section extends forwardly along the longitudinal axis
from said base section to said second intermediate section a
distance of about 0.22 to about 0.28 inches, said first
intermediate section and said base forming a fillet at the junction
thereof whereby said base forms a shoulder with said intermediate
section, said insert is fixedly held to said head portion by
brazing.
16. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having a coaxially aligned and integral sections, said
.[.section.]. .Iadd.sections .Iaddend.comprising a base section, a
tip section, a first intermediate section contiguous with said
base, a second intermediate section of uniform diameter contiguous
with said first intermediate and tip sections, said base being
fixedly mounted in said socket and having a first diameter of from
about 0.60 to about 0.66 inches, said tip section having a maximum
second diameter being from about 0.36 to about 0.44 inches and
being conically shaped with an included angle from about 83 degrees
to about 93 degrees, said first intermediate section having a
maximum third diameter, said second intermediate section having a
maximum fourth diameter equal to said maximum second diameter, said
second and third diameters each being less than said first
diameter, said first intermediate section has a frusto-conical
shape angling outwardly from the junction with said second
intermediate section to the junction with said base section at an
included angle of about 17 to about 23 degrees, said first
intermediate section and said base forming a fillet at the junction
thereof whereby said base forms a shoulder with said intermediate
section, said second intermediate section extending forwardly along
the longitudinal axis from said first intermediate section to said
second section a distance from about 0.02 to about 0.05 inches,
said insert is fixedly held to said head portion by brazing.
17. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having a coaxially aligned and integral sections, said section
comprising a base section, a tip section, a first intermediate
section contiguous with said base, a second intermediate section of
uniform diameter contiguous with said first intermediate and tip
sections, .Iadd.said second intermediate section extends forwardly
along the longitudinal axis from the junction with the first
intermediate section to the tip section a distance of about 0.02 to
about 0.05 inches, .Iaddend.said base being fixedly mounted in said
socket and having a first diameter of from about 0.60 to about 0.66
inches, said base section extends forwardly along the longitudinal
axis a distance of from about 0.05 to about 0.11 inches, said tip
section having a maximum second diameter being from about 0.36 to
about 0.44 inches and being conically shaped with an included angle
from about 83 degrees to about 93 degrees, said first intermediate
section having a maximum third diameter, said second intermediate
section having a maximum fourth diameter equal to said maximum
second diameter, said second and third diameters each being less
than said first diameter, said first intermediate section has a
frusto-conical shape angling outwardly from the junction with said
second intermediate section to the junction with said base section
at an included angle of about 17 to about 23 degrees, said first
intermediate section and said base forming a fillet at the junction
thereof whereby said base forms a shoulder with said intermediate
section, said insert is fixedly held to said head portion by
brazing..Iadd.
18. A rotatable cutting bit according to claim 1 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
19. A rotatable cutting bit according to claim 8 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
20. A rotatable cutting bit according to claim 9 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
21. A rotatable cutting bit according to claim 10 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
22. A rotatable cutting bit according to claim 11 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
23. A rotatable cutting bit according to claim 15 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
24. A rotatable cutting bit according to claim 16 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
25. A rotatable cutting bit according to claim 17 wherein said
second intermediate section extends forwardly along the
longitudinal axis from the junction with said first intermediate
section to the tip section a distance of about 0.03
inches..Iaddend..Iadd.
26. A rotatable cutting bit according to claim 1 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
27. A rotatable cutting bit according to claim 26 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
28. A rotatable cutting bit according to claim 26 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
29. A rotatable cutting bit according to claim 8 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
30. A rotatable cutting bit according to claim 29 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
31. A rotatable cutting bit according to claim 29 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
32. A rotatable cutting bit according to claim 9 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
33. A rotatable cutting bit according to claim 32 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
34. A rotatable cutting bit according to claim 32 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
35. A rotatable cutting bit according to claim 10 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
36. A rotatable cutting bit according to claim 35 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
37. A rotatable cutting bit according to claim 35 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
38. A rotatable cutting bit according to claim 11 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
39. A rotatable cutting bit according to claim 38 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
40. A rotatable cutting bit according to claim 38 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
41. A rotatable cutting bit according to claim 15 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
42. A rotatable cutting bit according to claim 41 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
43. A rotatable cutting bit according to claim 41 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
44. A rotatable cutting bit according to claim 16 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
45. A rotatable cutting bit according to claim 44 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
46. A rotatable cutting bit according to claim 44 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
47. A rotatable cutting bit according to claim 17 wherein the hard
insert having an overall axial length, and the second intermediate
section extends forwardly along the longitudinal axis from the
junction with the first intermediate section to the tip section a
distance that ranges between about 3.4 percent and about 11.4
percent of the overall axial length of the hard
insert..Iaddend..Iadd.
48. A rotatable cutting bit according to claim 47 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5
percent and about 9 percent of the overall axial length of the hard
insert..Iaddend..Iadd.
49. A rotatable cutting bit according to claim 47 wherein the
second intermediate section extends forwardly along the
longitudinal axis from the junction with the first intermediate
section to the tip section a distance that ranges between about 5.5
percent and about 6.5 percent of the overall axial length of the
hard insert..Iaddend..Iadd.
50. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, said sections
comprising a base section, a tip section, a first intermediate
section contiguous with said base, a second intermediate section of
uniform diameter contiguous with said first intermediate and tip
sections, said second intermediate section extends forwardly along
the longitudinal axis from the junction with said first
intermediate section to the tip section a fifth distance, said base
being fixedly mounted in said socket and having a first diameter,
said tip section being conically shaped and having a maximum second
diameter, said first intermediate section having a maximum third
diameter, said second intermediate section having a fourth diameter
equal to said maximum second diameter, said second and third
diameters each being less than said first diameter, said first
intermediate section has a frusto-conical shape and angles
outwardly from the junction with said second intermediate section
to the junction with said base section, said first intermediate
section at said base forming a fillet at the junction thereof
whereby said base forms a shoulder with said first intermediate
section, said insert is fixedly held to said head portion by
brazing, and the ratio of the fifth distance to the first diameter
ranging between about 0.03 and about 0.10..Iaddend..Iadd.
51. The rotatable cutting bit according to claim 50 wherein the
ratio of the fifth distance to the first diameter equals about
0.05..Iaddend..Iadd.
52. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, the hard insert
having an overall axial length equal to a sixth distance, said
sections comprising a base section, a tip section, a first
intermediate section contiguous with said base, a second
intermediate section of uniform diameter contiguous with said first
intermediate and tip sections, said second intermediate section
extends forwardly along the longitudinal axis from the junction
with said first intermediate section to the tip section a fifth
distance, said base being fixedly mounted in said socket and having
a first diameter, said tip section being conically shaped and
having a maximum second diameter, said first intermediate section
having a maximum third diameter, said second intermediate section
having a fourth diameter equal to said maximum second diameter,
said second and third diameters each being less than said first
diameter, said first intermediate section has a frusto-conical
shape and angles outwardly from the junction with said second
intermediate section to the junction with said base section, said
first intermediate section at said base forming a fillet at the
junction thereof whereby said base forms a shoulder with said first
intermediate section, said insert is fixedly held to said head
portion by brazing, and the ratio of the fifth distance to the
sixth distance ranging between about 0.03 and about
0.12..Iaddend..Iadd.
53. The rotatable cutting bit according to claim 52 wherein the
ratio of the fifth distance to the sixth distance ranges between
about 0.05 and about 0.07..Iaddend..Iadd.
54. A rotatable cutting bit comprising a head portion, a shank
portion depending from said head portion along a longitudinal axis,
said head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, the hard insert
having an overall axial length equal to a sixth distance, said
sections comprising a base section, a tip section, a first
intermediate section contiguous with said base, a second
intermediate section of uniform diameter contiguous with said first
intermediate and tip sections, said second intermediate section
extends forwardly along the longitudinal axis from the junction
with said first intermediate section to the tip section a fifth
distance, said base being fixedly mounted in said socket and having
a first diameter, said tip section being conically shaped and
having a maximum second diameter, said first intermediate section
having a maximum third diameter, said second intermediate section
having a fourth diameter equal to said maximum second diameter,
said second and third diameters each being less than said first
diameter, said first intermediate section has a frusto-conical
shape and angles outwardly from the junction with said second
intermediate section to the junction with said base section, said
first intermediate section at said base forming a fillet at the
junction thereof whereby said base forms a shoulder with said first
intermediate section, said insert is fixedly held to said head
portion by brazing, and the ratio of the fifth distance to the
first diameter ranging between about 0.03 and about 0.10, and the
ratio of the fifth distance to the sixth distance ranges between
about 0.03 and about 0.12..Iaddend..Iadd.
55. The rotatable cutting bit according to claim 54 wherein the
ratio of the fifth distance to the sixth distance ranges between
about 0.05 and about 0.07..Iaddend..Iadd.
56. The rotatable cutting bit according to claim 54 wherein the
ratio of the fifth distance to the first diameter equals about
0.05..Iaddend..Iadd.
57. The rotatable cutting bit according to claim 56 wherein the
ratio of the fifth distance to the sixth distance ranges between
about 0.05 and about 0.07..Iaddend.
Description
FIELD OF INVENTION
The present invention relates to a rotatable cutting bit of the
type having an improved head portion and depending shank.
BACKGROUND OF INVENTION
Bits that are used in mining and for removing road surfaces are
typically mounted in a machine having a power driven cutting
wheel.
When employed on abusive material such as concrete, the attack bits
encounter high pressures and undergo excessive steel wear around
the tip section. Currently employed conically shaped tips not only
experience degrees of blunting, thereby reducing machines speed,
but also suffer from the presence of manufacturing flaws which can
lead to total bit failure.
One example of commercially successful bits is described in U.S.
Pat. No. 4,497,520, issued on Feb. 5, 1985 to Ojanen and assigned
to the same assignee as the present invention. The patent discloses
and claims a rotatable cutting bit where the head portion consists
of a base section, a conical tip section with a maximum diameter,
and an intermediate section contiguous with the base and tip
sections. Under manufacturing conditions the dies used in forming
these bits experience wear at the point of maximum tip diameter
(the seam) resulting in unwanted accumulation of uncompressed
carbide material (flashing). Commonly known methods of polishing,
such as mechanical tumbling, remove the flashing but generate
stress cracks along the same thereby increasing the likelihood of
bit failure.
As a consequence of the commercial success of assignees Patent No.
4,497,520, consideration has now been given to improvements in
construction relative to methods of manufacture for such tooling
for better quality and control in production volumes.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided, a
rotatable cutting bit comprising a head portion, a shank portion
depending from said head portion along a longitudinal axis, said
head portion having a socket at the forward end, a hard insert
having coaxially aligned and integral sections, said sections
comprising a base section, a tip section, a first intermediate
section contiguous with said base, a second intermediate section of
uniform diameter contiguous with said first intermediate and tip
sections, said base being fixedly mounted in said socket and having
a first diameter, said tip section being conically shaped and
having a maximum second diameter, said first intermediate section
having a maximum third diameter, said second intermediate section
having a fourth diameter equal to said second diameter, said second
and third diameters each being less than said first diameter, said
first intermediate section at said base forming a fillet at the
junction thereof whereby said base forms a shoulder with said first
intermediate section.
The present invention alleviates the disadvantages of premature
blunting and the formation of manufacturing flaws by providing a
small diameter tip and by providing an adjoining cylindrical
intermediate section. In production, the tip end plunger completes
its compression stroke on a vertical section of the die rather than
on the angular seam section of the prior art, thereby reducing die
wear and the associated problems of flashing accumulation and
stress crack formation.
DRAWINGS
FIG. 1 is a partially sectioned view of a bit mounted in block.
FIG. 2 is a side view of a tip;
FIG. 3 is an end view of a tip; and
FIG. 4 is a cut-out side view of the fillet section joining the
first intermediate section and the base section.
DETAILED DESCRIPTION
Referring to the drawings, FIG. 1 shows a rotatable bit 11 having a
head portion 13 and a depending shank portion 15. The head portion
13 and shank 15 are coaxially aligned with the head 13 having an
enlarged section 17 which prevents the head 13 from being forced
into the opening in the mounting block 19. The shank portion 15
which is a cylindrical configuration includes a sleeve 21 which is
radially contracted when present in the opening so as to hold the
bit 11 in the block 19.
A hard insert 23 typically made of a carbide material is fixedly
secured to the forward end of the head 13. Preferably the base
section 25 of the insert 23 is positioned in the socket and brazed
in such a manner that the braze flows over and around the base
section 25.
In accordance with the principals of the present invention, the
insert 23 includes a plurality of sections coaxially aligned with
the head 13 and shank 15 of the bit 11. The sections include a base
section 25, a tip section 27, a first intermediate section 29
contiguous to both the base 25 and a second intermediate section
28, and a tip section 27 contiguous with the second intermediate
section 28.
The tip section 27 tapers outwardly at an included angle "c" of
from about 83 degrees to about 93 degrees. Preferably the angle is
about 88 degrees. The point portion of the tip may be rounded to
promote even wearing. Preferably the tip 27 extends downwardly in
an axial direction toward the base 25 a distance of from about 0.12
to about 0.18 inches. The maximum diameter of the tip 27 is from
about 0.36 to about 0.44 inches, and most preferably about 0.40
inches.
The second intermediate section 28 extends downwardly from the
junction with tip 27 or forwardly from the junction with the first
intermediate section 29 along a longitudinal direction a distance
of about 0.02 to about 0.05 inches and most preferably about 0.03
inches. The second intermediate section 28 is cylindrical in shape
and exhibits a uniform diameter equal to the maximum diameter of
the tip 27.
The first intermediate section 29 extends downwardly from the
juncture with the second intermediate section 28 or forwardly from
the juncture with the base 25 along a longitudinal direction a
distance of about 0.22 to about 0.28 inches. Preferably the first
intermediate section 29 has a frusto-conical shape and tapers
outwardly to the base section 25 at an included angle "d" of from
about 17 to about 23 degrees. The taper is outwardly from the
junction with the second intermediate section 28 to the junction
with the base 25. The first intermediate section 29 has a maximum
diameter less than the diameter of the base 25.
The base section 25 preferably has a diameter of from about 0.60 to
about 0.66 and most preferably about 0.63. The extension of the
base 25 in the axial direction or the height of the base is from
about 0.05 to about 0.11 inches preferably about 0.08. As
illustrated in FIG. 3 and FIG. 4, a fillet 30 may be utilized to
give a smooth transition from the base 25 to the first intermediate
section 29 whereby the base 25 forms a shoulder with the first
intermediate section 29. The transition is in the form of an arc of
radius between about 0.15 inches and about 0.25 inches which sweeps
out a distance starting from the base section 25 forwardly to a
diameter in the first intermediate section 24 of between about 0.54
to about 0.60 inches and preferably about 0.60. A more severe
transition between the first intermediate section 29 and the base
25 often results in the formation of stress cracks along the fillet
thereby increasing the likelihood of bit failure.
.Iadd.The total axial length of the hard insert is the sum of the
axial lengths of the tip section (0.12 inches to 0.18 inches), the
second intermediate section (0.02 inches to 0.05 inches) (which is
a fifth distance), the first intermediate section (0.22 inches to
0.28 inches), and the base section (0.05 inches to 0.11 inches). It
can this be seen that the axial length of the hard insert, which is
a sixth distance, can range between 0.41 inches to 0.62 inches.
Using the preferred dimensions, the axial length ranges between
about 0.45 inches and about 0.57 inches.
The ratio of the fifth distance, which is the axial length of the
second intermediate section, to the first diameter of the base
section ranges between about 0.03 and about 0.08. Based upon the
preferred dimensions, this ratio of the fifth distance to the first
diameter equals about 0.05.
The ratio of the fifth distance (the axial length of the second
intermediate section) to the sixth distance (the overall axial
length of the hard insert) has a range between a minimum ratio and
a maximum ratio. The minimum ratio is the ratio of the minimum
fifth distance (i.e., 0.02 inches) to the maximum sixth distance
that uses the minimum fifth distance. This sixth distance (i.e.,
0.59 inches) used to arrive at the minimum ratio equals the sum of
the maximum axial length of the tip section (0.18 inches), the
minimum axial length of the second intermediate section (0.02
inches), the maximum axial length of the first intermediate section
(0.28 inches), and the maximum axial length of the base section
(0.11 inches). This minimum ratio equals about (0.02/0.59) 0.03.
The maximum ratio is the ratio of the maximum fifth distance to the
minimum sixth distance that uses the maximum fifth distance. The
sixth distance equals the sum of the minimum axial lengths of the
tip section (0.12 inches), the first intermediate section (0.22
inches), and the base section (0.05 inches), and the maximum fifth
distance (0.05 inches). This maximum ratio equals about (0.05/0.44)
0.11. Based upon the preferred dimensions to the extent they are
set forth, the preferred ratio of the fifth distance to the sixth
distance ranges between about (0.03/0.57) 0.05 and about
(0.03/0.45) 0.07..Iaddend.
Since variations of this invention will be apparent to those
skilled in the art, it is intended that this invention be limited
only by the scope of the appended claims.
* * * * *