U.S. patent number 3,663,063 [Application Number 05/100,041] was granted by the patent office on 1972-05-16 for trenching implement.
Invention is credited to Hillard E. Johnmeyer, Sr..
United States Patent |
3,663,063 |
Johnmeyer, Sr. |
May 16, 1972 |
TRENCHING IMPLEMENT
Abstract
A trenching implement adapted for cutting a narrow trench in
rock or frozen ground comprising a wheel which is mounted for
rotation in a power trenching vehicle and which has a plurality of
cutting bit holders spaced at equal intervals around its periphery
with a cutting bit rotatably and removably mounted in each bit
holder. The bit holders are mounted in such positions on the wheel
as to hold all the cutting bits at the same positive rake angle,
certain of the bit holders holding the respective cutting bits in
the plane of the wheel, others holding the respective bits at skew
angles with respect to the plane of the wheel with the respective
bits extending out at one side of the wheel, and other holders
holding their respective bits at skew angles with respect to the
plane of the wheel with the respective bits extending out at the
other side of the wheel.
Inventors: |
Johnmeyer, Sr.; Hillard E.
(Vichy, MO) |
Family
ID: |
22277822 |
Appl.
No.: |
05/100,041 |
Filed: |
December 21, 1970 |
Current U.S.
Class: |
299/107; 37/452;
37/94; 299/39.3 |
Current CPC
Class: |
E02F
3/20 (20130101); E02F 9/2866 (20130101); E02F
3/188 (20130101) |
Current International
Class: |
E02F
9/28 (20060101); E02F 3/18 (20060101); E02F
3/20 (20060101); E02F 5/02 (20060101); E02f
005/08 () |
Field of
Search: |
;299/15,39,86,89
;37/91-97,142 ;175/373 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Purser; Ernest R.
Claims
What is claimed is:
1. A trenching implement comprising a wheel adapted for rotation on
its axis in a cutting direction, a plurality of identical cutting
bit holders secured on the periphery of the wheel spaced at
intervals around the periphery of the wheel, each bit holder
comprising a metal block having a base and a bore extending
therethrough in the central plane of the block between its sides
inclined at an angle with respect to said base, each block carrying
a cutting bit having a cylindrical shank rotatable in the bore of
the block, said cutting bit having a relatively hard conical outer
end constituting a cutting point, means for holding the shank of
each bit in the bore in its respective block while permitting the
bit to rotate and to be removed from the block, the wheel being of
a thickness corresponding generally to the width of a block and
being of large diameter relative to said thickness, each block
having its said base secured to the periphery of the wheel with the
respective bit disposed at a positive rake angle in respect to the
direction of rotation of the wheel, said rake angle corresponding
to the angle of inclination of the bore in the block relative to
the base of the block, certain blocks being secured on the
periphery of the wheel with the central planes thereof generally in
the plane of the wheel so as to hold the respective bits at said
rake angle in the plane of the wheel, other blocks being secured on
the periphery of the wheel with the central planes thereof at a
skew angle with respect to the plane of the wheel in such position
as to hold the respective bits at skew angles with respect to the
plane of the wheel and with the respective bits extending out at
one side of the wheel, and other blocks being secured on the
periphery of the wheel with the central planes thereof at a skew
angle with respect to the plane of the wheel in such position as to
hold the respective bits at skew angles with respect to the plane
of the wheel and with the respective bits extending out at the
other side of the wheel, each said skew angle being the angle
formed by the intersection of the plane of the wheel and the said
central plane of the respective block, the latter containing the
axis of the respective cutting bit and the center of the wheel, the
skew angles of certain of said skew-angled bits being such that
their cutting points are located outward of the sides of the
wheel.
2. A trenching implement comprising a substantially solid metal
disk adapted for rotation on its axis in a cutting direction, a
plurality of cutting bit holders welded on the periphery of the
disk spaced at intervals around the periphery of the disk, each bit
holder comprising a metal block having a base and a bore extending
therethrough inclined at an angle with respect to said base, each
block having a cutting bit rotatable in its said bore, said cutting
bit having a relatively hard conical outer end constituting a
cutting point, the disk being of a thickness corresponding
generally to the width of a block and being of large diameter
relative to its thickness, each block having its said base welded
to the periphery of the disk with the respective bit disposed at a
positive rake angle in respect to the direction of rotation of the
disk, certain blocks being welded on the periphery of the disk in
such position as to hold the respective bits at said rake angle in
the plane of the disk, other blocks being welded on the periphery
of the disk in such position as to hold the respective bits at skew
angles with respect to the plane of the disk and with the
respective bits extending out at one side of the disk, and other
blocks being welded on the periphery of the disk in such position
as to hold the respective bits at skew angles with respect to the
plane of the disk and with the respective bits extending out at the
other side of the disk, each said skew angle being the angle formed
by the intersection of the plane of the disk and the plane
containing the axis of the respective cutting bit and the center of
the disk, wherein each bit has a cylindrical shank rotatable in its
respective block, and means for holding the shank of each bit in
the bore in its respective block while permitting the bit to rotate
and to be removed from the block, and wherein the blocks and bits
are arranged in sets, each set comprising a first bit in the plane
of the wheel, second and third bits at a first skew angle extending
out at opposite sides of the wheel, and fourth and fifth bits at a
second and greater skew angle extending out at opposite sides of
the wheel.
3. A trenching implement as set forth in claim 2 wherein each set
further comprises sixth and seventh bits extending out at opposite
sides of the wheel at a third skew angle greater than the second
skew angle.
4. A trenching implement as set forth in claim 3 wherein the first
skew angle is about 12.degree. , the second is about 18.degree. and
the third is about 22.degree..
5. A trenching implement as set forth in claim 4 wherein the rake
angle is from about 43.degree. to about 47.degree..
Description
BACKGROUND OF THE INVENTION
This invention relates to a trenching implement, and more
particularly to a cutting wheel capable of cutting a trench in rock
as well as in frozen ground.
The invention is especially concerned with a toothed trench cutter
wheel for use on a power trenching vehicle for cutting a trench in
frozen ground and in rock for laying underground electrical cables,
pipe and the like. Such wheels have heretofore been used on a
vehicle having means for driving the wheel and lifting and lowering
it, but prior wheels have at best been capable of trenching in
frozen ground, not in rock (even relatively soft rock such as
limestone) without having their teeth wear out or otherwise fail
after cutting only a few feet of trench.
SUMMARY OF THE INVENTION
Among the several objects of the invention may be noted the
provision of a toothed trench cutter wheel for use on a vehicle as
above described adapted to cut a trench in rock as well as in
frozen ground without excessive tooth wear or other failure; and
the provision of such a wheel adapted to cut a clean trench, laying
up the cuttings on either side of the trench for back-filling after
laying of the cable or pipe in the trench.
In general, a trenching implement of this invention comprises a
wheel constituted by a substantially solid metal disk, adapted for
rotation on its axis in cutting direction, a plurality of cutting
bit holders welded on the periphery of the disk; spaced at
intervals around the periphery of the disk, and a cutting bit
rotatably and removably mounted in each holder, each holder being
mounted in such position on the periphery of the disk as to hold
the respective bit at a positive rake angle with respect to the
direction of rotation of the disk. Certain bit holders are mounted
in such position on the periphery of the disk as to hold the
respective bits in the plane of the disk. Other holders are mounted
in such position on the periphery of the disk as to hold the
respective bits at skew angles with respect to the plane of the
disk and with the respective bits extending out at one side of the
disk, and other holders are mounted in such position on the
periphery of the disk as to hold the respective bits at skew angles
with respect to the plane of the wheel and with the respective bits
extending out at the other side of the wheel.
Other objects and features will be in part apparent and in part
pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective of a trenching machine mounting an
implement of this invention;
FIG. 2 is a view showing an implement of this invention cutting a
trench;
FIG. 3 is a developed view of a segment of the peripheral edge of
the implement showing the arrangement of certain cutter holders and
bits;
FIG. 4 is a side elevation of a bit holder; and
FIG. 5 is an enlarged vertical section of a bit holder on line 5--5
of FIG. 3.
Corresponding reference characters indicate corresponding parts
throughout the several views of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, FIG. 1 shows a conventional power
trenching vehicle, generally designated by the reference numeral 1,
having a trenching implement of this invention indicated at 3
mounted therein for rotation on its axis. The trenching implement
comprises a relatively large-diameter cutting wheel 5 having a
plurality of cutting bit holders each designated by the reference
numeral 7 spaced around its periphery, with a cutting bit 9
removably mounted in each holder. As shown in FIG. 2, the holders 7
are mounted in such position on the periphery of the wheel 5 as to
hold all the bits 9 at a positive rake angle R (as will be
hereinafter defined) with respect to the direction of rotation of
the wheel. Additionally, certain bit holders as indicated at A in
FIG. 3 are mounted in such position on the periphery of the wheel
as to hold their respective bits in the plane of the wheel. Other
bit holders as indicated at B, D and F are mounted in such position
on the periphery of the wheel as to hold their respective bits as
skew angles (as will be hereinafter defined) with respect to the
plane of the wheel and with the respective cutting bits mounted
therein extending out at one side of the wheel (its right side as
shown in FIG. 3). Still other bit holders as indicated at C, E and
G are mounted in such position on the periphery of the wheel as to
hold their respective bits at skew angles with respect to the plane
of the wheel and with the respective cutting bits mounted therein
extending out at the other side of the wheel (its left side as
shown in FIG. 3).
More particularly, the power trenching vehicle 1 is adapted to
excavate a substantially vertical trench in the ground for the
laying of underground electrical cable, pipe and the like. It has a
pivoted yoke 11 in which wheel 5 is rotatably mounted, means
indicated at 13 for driving the wheel counterclockwise as shown in
FIGS. 1 and 2, hydraulic cylinder means indicated at 15 for raising
and lowering the yoke and the wheel mounted therein for cutting
trenches of different depths, and endless track means 17 for
propelling the vehicle in the direction of arrows shown in FIGS. 1
and 2 for trench cutting feed purposes.
The cutting wheel 5 comprises a solid steel disk approximately 1
inch thick and 9 feet in diameter, for example. The wheel is
secured on a center shaft 19 adapted to be driven by the driving
means 13.
Referring to FIGS. 4 and 5, each bit holder 7 comprises a metal
block or body 21 having a bore 23 extending therethrough from one
end to the other in the central plane thereof between its side
inclined at an angle of 45.degree. as shown to a base 25 of the
body. The thickness of the wheel or disk 5 corresponds generally to
the width of a block 21 (see FIG. 3). The bore 23 is countersunk at
its high end (its left end as shown in FIG. 5) as indicated at 27,
and the block or body 21 is provided with a transverse hold 29
therethrough tangentially intersecting the bore adjacent its low
end. The cutting bit 9 has a cylindric shank 31 rotatable in the
bore and a cylindric outer end portion 33 having a conically
pointed relatively hard outer end 35 (of tungsten carbide or the
like) constituting its cutting point. At the root of the outer end
portion is an enlargement 37 having a conical portion 39 engageable
in the countersink 27, this enlargement having an annular groove
41. The shank has an annular groove 43 loosely receiving a spring
ring 45 having outwardly extending bosses 47 one of which appears
in FIG. 5 snapped into the groove provided by hole 29. This holds
the bit in the holder while permitting the bit to rotate, and the
bit is readily removed from and inserted in the holder via the high
end of the bore 23.
In accordance with this invention, each bit holder 7 has its base
25 secured by welding (see FIGS. 4 and 5) to the periphery of the
wheel or disk so that all the cutting bits have substantially the
same positive rake angle R, as shown in FIG. 2. The rake angle R
may be defined as the angle formed by the axis of the bit and the
tangent to the wheel at the intersection of the axis of the bit and
the periphery of the wheel, as shown in FIG. 2, and corresponds to
the angle of inclination of the bore 23 in the block relative to
the base 25 of the block. As shown in FIG. 3, the bit holders or
disks are oriented relative to the plane of the wheel such that
some of the cutting bits are in the plane of the wheel, and other
cutting bits are angled outwardly from the plane of the wheel at
skew angles S. The skew angle S may be defined as the angle formed
by the intersection of the plane of the wheel and the plane
containing the axis of the cutting bit and the center of the
wheel.
In FIG. 2, the bit holders 7 are shown to be arranged in sets
indicated at 49 around the wheel 5 with the number of sets
depending on the number of bits in each set and the diameter of the
wheel. A typical set of seven bit holders holding seven bits is
shown in FIG. 3, with the first bit holder A in the plane of the
wheel (i.e., the central plane of this bit holder or block A is in
the plane of the wheel), the second and third bit holders in the
set, B and C, respectively, being mounted with the central planes
thereof at at a first skew angle S1 (e.g., 12.degree.) with respect
to the plane of the wheel and with the bits mounted therein
extending out at opposite sides of the wheel, the fourth and fifth
bit holders, D and E, respectively, being mounted with the central
planes thereof at at a second and greater skew angle S2 (e.g.,
18.degree.) with respect to the plane of the wheel and with the
respective bits extending out at opposite sides of the wheel, and
with the sixth and seventh bit holders, F and G, respectively,
being mounted with the central planes thereof at a third skew angle
S3 which is greater than S2 (e.g., 22.degree.) with respect to the
plane of the wheel and with the respective bits extending out at
opposite sides of the wheel. These values of 12.degree., 18.degree.
and 22.degree. for the skew angles are preferred. It will be
observed from FIG. 3 that the 22.degree. angled bits have their
cutting points located substantially outward of the planes of the
side faces of the wheel or disk 5.
In operation, the trenching vehicle 1 is moved into position by
means of tracks 17, the hydraulic cylinders 15 are actuated to
lower the cutting implement 3 to contact the rock (or ground), and
the cutting wheel 5 is driven (counterclockwise as shown in FIG. 1)
by driving means 11. As the implement begins to cut, it is further
lowered into the ground until the desired trench depth is attained.
The trenching vehicle is then slowly moved on tracks 17 in the
direction of the arrow shown in FIG. 1 to cut the trench. The speed
at which the implement cuts the trench depends on the depth of the
trench and the composition of the material being trenched.
Typically, trenches 30 inches deep may be dug in rock formations
such as limestone (dolomite) at a rate of approximately 2 feet per
minute, and trenches of similar depth may be dug in frozen earth at
a rate of 6 feet per minute.
As shown in FIG. 2, the cutting bits first contact the ground at
the bottom of the trench and are moved upwardly toward the
trenching vehicle as the wheel is rotated counterclockwise. The
cutting bits break and cut the rock (or frozen earth) within the
trench leaving relatively smooth trench walls, and carry the loose
cuttings upwardly to be deposited on opposite sides of the trench
for back-filling after the laying of the cable or pipe within the
trench. A small quantity of loose rock and soil is left at the
bottom of the trench to provide a smooth base for the laying of
electrical cable and the like. As the cutting bits contact the rock
(or soil) being cut, the bits are caused to rotate within the bit
holders 7. The rotation of the cutting bits within the bit holders
insures that the cutting tips 35 will wear evenly and remain sharp,
thereby maintaining their cutting efficiency and extending their
useful life. It has been found that the bits are more likely to
rotate if the positive rake angle R is between 43.degree. and
47.degree. (and preferably 45.degree. as shown).
Trench widths of approximately 4 inches may be obtained with
cutting bits 9 having a maximum skew angle of 22.degree.. If
trenches substantially wider than 4 inches are desired, two or more
trenching implements 3 may be mounted on shaft 19 and driven
simultaneously to cut side-by-side trenches in the ground.
In view of the above, it will be seen that the several objects of
the invention are achieved and other advantageous results
attained.
As various changes could be made in the above constructions without
departing from the scope of the invention, it is intended that all
matter contained in the above description or shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
* * * * *