U.S. patent number 3,858,670 [Application Number 05/389,742] was granted by the patent office on 1975-01-07 for insert cutter for cutting kerfs.
Invention is credited to William Michael Conn, Eugene Gray Ott.
United States Patent |
3,858,670 |
Ott , et al. |
January 7, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
INSERT CUTTER FOR CUTTING KERFS
Abstract
An insert cutter for an earth boring machine that functions to
form a plurality of circular kerfs in the earth formations being
bored thereby fracturing the portion of the formations between a
proximate pair of kerfs and causing fragments of the formations to
be separated from the formations being bored. A multiplicity of
annular rows of tungsten carbide inserts are positioned in the
cutter body thereby simulating the formation loading of a disk
cutter. Each insert has an elongated formation contacting head and
all of the heads of the inserts in an annular row are aligned. An
annular row of inserts functions to form a circular kerf in the
earth formation being bored as the cutter is moved along the
formation. The cutting structure interruption (C.S.R.) in an
annular row of inserts is less than the pitch cord (P.C.) of the
annular row.
Inventors: |
Ott; Eugene Gray (Dallas,
TX), Conn; William Michael (Dallas, TX) |
Family
ID: |
26941714 |
Appl.
No.: |
05/389,742 |
Filed: |
August 20, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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251607 |
May 8, 1972 |
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Current U.S.
Class: |
175/374;
175/426 |
Current CPC
Class: |
E21B
10/10 (20130101); E21B 10/52 (20130101) |
Current International
Class: |
E21B
10/52 (20060101); E21B 10/10 (20060101); E21B
10/46 (20060101); E21B 10/08 (20060101); E21b
009/10 (); E21b 009/36 (); E21c 013/01 (); E21c
013/02 () |
Field of
Search: |
;175/371-374,351,354,410 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Attorney, Agent or Firm: Scott; Eddie E.
Parent Case Text
BACKGROUND OF THE INVENTION
This is a continuation-in-part of application Ser. No. 251,607,
filed May 8, 1972 now abandoned. The present invention relates to
the art of earth boring and, more particularly, to an insert cutter
for cutting kerfs in the formations being bored.
Claims
The embodiments of the invention in which an exclusive property or
priviledge is claimed are defined as follows:
1. An earth boring cutter that functions to form at least one kerf
in the formations being bored, comprising:
a cutter body, said cutter body having an annular cutter body
surface; and
at least one annular row of insert means projecting from said
cutter body for forming a kerf in the formation being bored, said
at least one annular row of insert means including a multiplicity
of individual non-hollow inserts which said inserts having
cylindrical body portions extending into said cutter body below
said annular cutter body surface and head portions extending
substantially above said annular cutter body surface with said head
portions having elongated formation contacting surfaces with said
elongated formation contacting surfaces being aligned to form a
kerf in the formations being bored.
2. The earth boring cutter of claim 1 where said inserts have a
cutting structure interruption that is less than five-eights
inch.
3. The earth boring cutter of claim 2 wherein said inserts have a
cutting structure interruption that is less than 75% of the pitch
cord.
4. The earth boring cutter of claim 3 wherein said inserts have a
cutting structure interruption that is less than 70% of the pitch
cord.
5. The earth boring cutter of claim 4 where said inserts have a
cutting structure interruption that is approximately 62.5% of the
pitch cord.
6. An earth boring cutter that functions to form at least one kerf
in the formations being bored, comprising:
a cutter body, said cutter body having an annular cutter body
surface; and
at least one annular row of solid inserts projecting from said
cutter body for forming a kerf in the formation being bored, said
inserts having a cylindrical body portion extending into said
cutter body below said annular cutter body surface, a head portion
extending substantially above said annular cutter body surface, a
leading flank, a trailing flank, an inner flank and an outer flank,
with said leading flank and trailing flank being substantially
parallel and said inner and outer flanks susbstantially meeting to
form a formation contacting surface with said formation contacting
surfaces being in a common plane.
7. The earth boring cutter of claim 6 where said inserts have a
cutting structure interruption of less than one-half inch.
8. The earth boring cutter of claim 7 wherein said inserts have a
cutting structure interruption of less than three-eights inch.
9. A cutter for an earth boring machine wherein said cutter is
adapted to be mounted upon a rotary unit of the earth boring
machine with said rotary unit functioning to form a multiplicity of
circular kerfs in the earth formation being bored to fracture the
portion of the formations between a proximate pair of said kerfs in
a manner to cause fragments of the formations to be separated from
the formations being bored, comprising:
a cutter body, said cutter body having an annular surface; and
at least two annular rows of insert means connected to said cutter
body and projecting from said annular surface for forming at least
two circular kerfs in the earth formations being bored, said at
least two annular rows of insert means including a multiplicity of
individual solid inserts with said inserts having a cylindrical
body portion embedded in said cutter body below said annular
surface, a head portion projecting outward substantially above said
annular surface, and an elongated formation contacting surface with
the elongated formation contacting surfaces of all the inserts in
annular row being aligned to form a circular kerf in the earth
formations being bored.
10. The cutter of claim 9 wherein said inserts have a cutting
structure interruption that is less than 75% of the pitch cord.
11. The cutter of claim 10 wherein said inserts have a cutting
structure interruption that is less than 70% of the pitch cord.
12. The cutter of claim 11 wherein said inserts have a cutting
structure interruption that is approximately 62.5% of the pitch
cord.
13. A cutter for an earth boring machine wherein said cutter is
adapted to be mounted upon a rotary unit of the earth boring
machine with said rotary unit functioning to form a multiplicity of
circular kerfs in the earth formations being bored to fracture the
portion of the formations between a proximate pair of said kerfs in
a manner to cause fragments of the formations to be separated from
the formations being bored, comprising:
a cutter body, said cutter body having an annular plane surface;
and
at least two annular rows of solid inserts connected to said cutter
body and projecting from said annular plane surface for forming at
least two circular kerfs in the earth formations being bored, said
inserts having cylindrical body portions extending into said cutter
body below said annular plane surface and head portions extending
substantially above said annular plane surface with said head
portions having elongated contacting surfaces with said elongated
formations contacting surfaces in an annular row being aligned to
form circular kerfs in the formations being bored to fracture the
portion of the formations between proximate kerfs, said inserts
having a cutting structure interruption that is less than
five-eighths inch.
14. The cutter of claim 13 wherein said inserts have a cutting
structure interruption that is less than one-half inch.
15. The cutter of claim 14 wherein said inserts have a cutting
structure interruption that is less than three-eights inch.
Description
Conventionally, rotary drilling appartus and, particularly rotary
drilling apparatus for boring large diameter holes and tunnels,
includes a multiplicity of roller cutters. These roller cutters are
formed of either conical, cylindrical or disk configuration. A
number of the roller cutters together with their bearings and the
saddles or arms in which the cutters and bearings are supported are
mounted on a rotary head or bit and used to form holes in the
formations being bored. The roller cutters may be conveniently
mounted on the rotary cutting head of a tunneling machine or on the
body of a raise bit and are adapted to be easily and quickly
interchanged.
A tooth-type or insert roller cutter generally ranges from a
cylindrical configuration to a somewhat conical configuration and
includes milled steel teeth or carbide inserts on the cutting
surface. This type of cutter is adapted for cutting formations
ranging all of the way from very soft to extremely hard. The
tooth-type roller cutter is usually a full face cutter, i.e., it is
paired with another cutter to insure that the bottom is well
covered by the cutter teeth which will tear out, scrape out or
crush out individual areas of the formation to be bored. As a
formation becomes very hard and abrasive, the cutting structure
usually employs sintered tungsten carbide buttons or tooth-shaped
inserts. The formation being bored sees the cutting structure as a
multiplicity of point load contacts each one spalling out a
relatively small circle of bottom. The bottom does not completely
break out between rows, and it is necessary to run a paired cutter
with compacts spaced to cut the spaces (or uncut bottom) between
the rows on the previous cutter. This type of cutter arrangement
requires a pair of cutters to completely destroy bottom in one
revolution.
A disk-type cutter is effective in very soft to medium formations.
The disk is usually a heat treated alloy steel cutter with an
inclined angle between about 60.degree. and 90.degree.. The disk
cutters are usually indexed 2 or 3 inches apart. In effect, the
disk cutters plow concentric circles around the face of the
formation being bored. The cutting disks are indexed so that the
formation between disks will break out completely under a given
load and RPM. This is a very efficient way to cut formations
because the cuttings come off the face in relatively large pieces
instead of the small cuttings obtained from tooth-type cutters with
the full face cutting principal. Disk cutters have not been
economical in hard formations because the alloy steel disk dulls
out quickly in the harder abrasive formations. This is especially
detrimental in a shaft drilling or raise drilling operation where
trip time is costly. It is not practical to make the disks
completely of carbide and the brazing on of continuous sintered
carbide tips or wedges is also of questionable feasilbity from an
economical and operational standpoint.
The present invention may be advantageously used on tunneling
machines, continuous mining machines, raise drills, rock bits, and
other types of earth boring bits and machines. The cutter of the
present invention is rotatably connected to the bit or the rotary
head of the earth boring machine and serves to cut a series of
kerfs in the formations being bored.
DESCRIPTION OF THE PRIOR ART
A general understanding of the prior art relating to tooth-type or
insert cutters may be obtained from a consideration of the
disclosures of the following U.S. Patents in U.S. Pat. No. NO.
3,389,760 to W. V. Morris, patented June 25, 1968, a toothtype
rolling cutter is shown. This cutter may include either inserts or
steel teeth on the cutting surface. In U.S. Pat. No. 3,570,613 to
W. D. Coski, patented March 16, 1971, a gage cutter for an earth
boring machine is shown. The cutter includes a plurality of rows of
cutter elements about the periphery thereof with the rows being of
such size and position so as to define an oblate cylinder cutting
envelope or plane to equalize the load on the cutting elements. In
U.S. Pat. No. 3,593,812 C. R. Peterson, patented July 20, 1971, a
rock cutter is shown. The cutter is formed of a stack of
juxtapositioned cutter disks with said disks each having projecting
carbide bits.
A representative indication of the prior art relating to disk-type
cutters is obtainable from a consideration of the disclosures of
the following U.S. Patents. In U.S. Pat. No. 2,766,977 to J. S.
Robbins patented Oct. 16, 1956, a rotary cutter head for boring
type continuous mining machines is shown. A multiplicity of
disk-type cutters are mounted on the rotary head of the mining
machine for contacting and disintegrating the formations. In U.S.
Pat. No. 3,216,513 to R. J. Robbins et al., patented Nov. 9, 1965,
a disk-type cutter assembly for rock drilling is shown. The disk
cutter includes a plurality of relatively hard tooth members
embedded in the disk cutting edge which facilitates the kerf
forming action of the cutter and improves the cutter edge life. In
U.S. Pat. No. 3,139,148 to J. S. Robbins, patented June 30, 1964, a
rotary boring head having roller cutter disks is shown. The disks
are adapted to contact and disintegrate the formations. In U.S.
Pat. No. 3,596,724 to K. G. Beecham patented Aug. 3, 1971, a
cutting roller for use in rock boring equipment and having two
circumferentially extending parallel ribs is shown. Each of the
ribs is provided with a series of wear resistant exchangeable
inserts which protect the crown and flank surfaces of the rib
against wear. In U.S. Pat. No. 3,430,718 to J. C. Lawrence,
patented Mar. 4, 1969, a roller cutter for rotary drilling
apparatus is shown. The roller cutter includes a circumferential
cutting edge located in a plane which intersects the axis of the
cutter at an oblique or acute angle. A plurality of cutting points,
preferably formed from embedded carbide inserts, are positioned in
the rim of the cutter body. In U.S. Pat. No. 3,572,452 to D. F.
Winberg, patented Mar. 30, 1971, a roller cutter is shown with a
bit in the form of a ring or disk, encircling the roller cutter.
The cutting edge of the bits are formed by two flat surfaces that
may be considered to be planes which rise to an edge.
SUMMARY OF THE INVENTION
The present invention provides an insert cutter that will serve to
cut kerfs in the formations being bored. At least one annular row
of inserts is positioned in the cutter body and the annular row of
inserts simulates the formation loading of a continuous disk. The
inserts have an elongated formation contacting head portion and the
elongated head portions of the inserts in the annular row are
aligned. The cutting structure interruption in said annular row of
inserts is less than the pitch cord of said annular row of inserts.
The cutter of the present invention will entirely disintegrate a
swath of formation in a single rotation of the cutter head and
therefore will operate effectively without being paired with
another cutter.
The aforementioned advantages of the present invention and other
features and advantages will become apparent from a consideration
of the following detailed description of the invention when taken
in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a cutter of the present invention contacting a
formation.
FIG. 2 illustrates a prior art disk cutter contacting a
formation.
FIG. 3 illustrates a prior art insert cutter contacting a
formation.
FIG. 4 is an illustrative view of an insert cutter constructed in
accordance with the present invention positioned in a saddle that
is adapted to be connected to the rotary head of an earth boring
machine.
FIG. 5 is an end view of a portion of the cutter of FIG. 4 showing
the cutting structure interruption of the inserts.
FIG. 6 is an illustrative end view of a portion of a cutter of the
prior art showing structure interruption of the inserts.
FIG. 7 is a perspective view illustrating one of the inserts of the
cutter shown in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, the operation of a cutter constructed in
accordance with the present invention is illustrated. The cutter,
generally designated by the reference number 50, includes a
multiplicty of tungsten carbide inserts 51 arranged to form a
series of annular rows. The individual inserts 51 are mounted in a
cutter shell 52. The cutter sheel 52 is rotatably mounted in a
saddle 53. The saddle 53 may be connected to the rotary head of an
earth boring machine or to the body of an earth boring drill. The
annular rows of inserts act upon the formation 54 to form a
multiplicity of kerfs 55. The desired hole is formed by continually
cutting a multiplicity of circular kerfs in the earth formations
being bored, thereby fracturing the portion of the formations
between a proximate pair of kerfs and causing fragments of the
formations to be separated from the formations being bored.
Referring now to FIG. 2, a prior art disk cutter is shown. The
cutting action of a disc cutter has been described by Frank F.
Roxborough and Alan Rispin in the article, "The Mechanical Cutting
Characteristics of the Lower Chalk" in Tunnels and Tunneling, Jan.
1973 as follows:
"A solid steel disc with a pointed circumferential edge. The disc
operates as a free rolling wheel in which a high thrust forces the
sharpened circumference to penetrate the rock face. A superimposed
translatory motion causes the disc to roll, gouging a furrow in the
rock in much the same way as a heavily loaded wheel rolling over
yielding ground."
The disk 56 shown in FIG. 2 is rotatably mounted in a saddle 57.
The saddle 57 may be connected to the rotary head of an earth
boring machine or to the body of an earth boring drill. The disk 56
forms a kerf 58 in the formation 59.
Referring now to FIG. 3, a prior art insert cutter is illustrated.
The cutting action of an "insert cutter" or "button cutter" has
been described by Frank F. Roxborough and Alan Rispin in the
article, "The Mechanical Cutting Characteristics of the Lower
Chalk" in Tunnels and Tunneling, Jan. 1973 as follows:
"This is very much a grinding tool. It usually takes the form of a
free rolling cylinder or cone frustum, the surface of which is
studded with tungsten carbide buttons. It is operated in a similar
fashion to the disc and roller cutter. A high penetrating force
into the rock surface, supplemented by a translatory motion to the
tool, causes rock degradation by grinding and pulverisation."
The insert cutter 60 is rotatably mounted in a saddle 61. The
saddle 61 may be connected to the rotary head of an earth boring
machine or to the body of an earth boring bit. A multiplicity of
inserts 62 project from the surface of the cutter 60. The inserts
62 act upon the formation 63 to crush out individual areas of the
formation to be bored thereby forming the desired hole.
Referring now to FIG. 4, a cutter constructed in accordance with
the present invention is illustrated. The cutter includes a
multiplicity of carbide inserts arranged to form a series of
annular rows 1 through 8. The cutter, generally designated by the
reference numeral 9, includes 350 individual sintered tungsten
carbide inserts, each designated by the reference numeral 10,
mounted in a cutter shell 11. The cutter shell 11 is positioned
around a bearing shell 12 and bearing shell 12 is securely locked
in a saddle 13. The saddle 13 may be connected to the rotary head
of an earth boring machine or to the body of an earth boring bit.
It is to be understood that the cutter 9 could also be in the form
of a conical cutter adapted to be journaled on one of the arms of a
rotary rock bit. It is also to be understood that the cutter 9
could be constructed to include a single annular row of inserts for
forming a single kerf in the formations and that the cutter 9 could
cooperate with another cutter to fracture the formations between a
pair of kerfs.
The bearing shell 12 is locked in position in the saddle 13 by a
main pin 14 and a retainer nail or roll pin 15. The bearing shell
12 remains firmly locked in place throughout the drilling operation
due to a tenon and groove arrangement disclosed in U.S. Pat. No.
3,203,492 to C. L. Lichte, patented Aug. 31, 1965. A multiplicity
of bearing systems including a series of ball bearings 16, a series
of inner roller bearings 17 and a series of outr roller bearings 18
promote rotation of the cutter shell 11 about the bearing shell 12.
Lubricant is retained in the bearing area by two sets of seal
elements. The inner set of seal elements includes a pair of annular
metal seal rings 19 and 20 that are positioned near the inner end
of the cutter 9. A flexible rubber O-ring 21 is positioned between
seal ring 19 and the bearing shell 12 to retain the seal ring 19 in
the desired position and resiliently urge seal ring 19 against seal
ring 20. A flexible rubber O-ring 22 is positioned between the
cutter shell 11 and the seal ring 20 to retain the seal ring 20 in
the desired position and resiliently urge the seal ring 20 against
seal ring 19. The outer set of seal elements includes a pair of
annular metal seal rings 23 and 24 that are positioned near the
outer end of the cutter 9. A flexible rubber O-ring 25 is
positioned between the seal ring 24 and bearing shell 12 to retain
the seal ring 24 in the desired position and reiliently urge sal
ring 24 against seal ring 23. A flexible rubber O-ring 26 is
positioned between the cutter shell 11 and the seal ring 23 to
retain seal ring 23 in the desired position and resiliently urge
sal ring 23 against seal ring 24.
Referring now to FIG. 5, an end view of a portion of the cutter
shell 11 is shown in partial section. Two adjacent inserts 10 are
shown positioned in the cutter shell 11. Each of the inserts 10
have an elongated head portion 27 that is adapted to contact the
formations. The distance between each of the central axes 28 of the
two adjacent inserts 10 measured at the respective heads 27 is
defined as the pitch cord (P.C.). The P.C. of inserts 10 is
eight-tenths of an inch. The distance between the nearest points 29
of adjacent head portions 27 of the inserts 10 is defined as the
cutting structure interruption (C.S.R.). The C.S.R. of inserts 10
is one-half of an inch. The C.S.R. of cutter shell 11 is therefore
less than the P.C. of the cutter shell 11. The elongated head
portions 27 of the inserts 10 are aligned to simulate the formation
loading of a disk cutter. To insure the proper formation loading,
the C.S.R. of inserts 10 should be within the range of from
three-eights of an inch to five-eights of an inch. It will
therefore be appreciated that the C.S.R. of the inserts 10 should
be less than 78% of the P.C. to obtain the proper formation
loading. When the C.S.R. is a maximum (five-eights inch) it will be
approximately 78% of the P.C. (eight-tenths inch). As shown in FIG.
5, the C.S.R. is approximately 62.5%. Cutters within the
aforementioned range have been found to obtain faster penetration
rates than prior art insert cutters and to have a longer lifetime
than prior art disk cutters.
Referring now to FIG. 6, an end view of a portion of prior art
cutter 30 is shown in partial section. Two adjacent inserts 31 are
shown positioned in the cutter 30. The head portion 32 of each of
the inserts 31 are relatively pointed and are clearly distinct from
the elongated head portion of the inserts shown in FIG. 2. In
general the head portions of prior art inserts have been pointed or
rounded; however, in some instances, the head portions have been in
the form of a chisel-shaped head. The chisel-shaped head inserts of
the prior art have not been arranged to have the heads in each
annular row aligned and the specific shape of the prior art
chisel-shaped head inserts has been distinct from the shape of
inserts 10. It should be noted that the C.S.R. and P.C. of the
prior art cutter 30 are subtantially equal.
Referring now to FIG. 7, a single insert 33 constructed in
accordance with the present is illustrated. The insert 33 has a
cylindrical body 34 adapted to be secured in a cutter such as the
cutter 9 shown in FIG. 4. The upper end of the insert 33 forms a
chisel-shaped formation contacting head. The leading flank 35 and
the trailing flank 36 are substantially parallel whereas the inner
flank 37 and the outer flank 38 tend to converge. The prior art
chisel-shaped head inserts include leading flanks and trailing
flanks that are inclined compared to the substantialy parallel
leading and trailing flanks of insert 33. This provides the head
portion of the insert 33 with an elongated formation contacting
surface 39. The elongated formation contacting surface 39 of the
inserts in each annular row are aligned to simulate the formation
loading of a disk cutter.
The structural details of a cutter constructed in accordance with
the present invention having been described, the operation of the
cutter 9 will now be considered. The saddle 13 is connected to a
rotary drilling head or bit and the head or bit is rotated and
moved through the formations. The inserts 10 contact the formations
and form a plurality of circular kerfs therein. The portions of the
formations between adjacent kerfs tend to fracture out and the
fragments are separated from the formations being bored to form the
desired hole or tunnel. The elongated heads 27 of the inserts 10 in
each annular row (1 through 8) simulate a continuous line contact
with the formations rather than the point contacts known in the
prior art. The continuous line contact serves to form individual
kerfs in the formations being bored. The cutter 13 will therefore
disintegate a complete swath of formation with a single rotation of
the rotary head or bit thereby eliminating the need for a training
or paired cutter.
* * * * *