U.S. patent application number 13/333013 was filed with the patent office on 2013-06-27 for dozing blade assembly, cutter and dozing method.
This patent application is currently assigned to Caterpillar, Inc.. The applicant listed for this patent is Nick W. Biggs, Thomas M. Congdon, Kevin L. Martin. Invention is credited to Nick W. Biggs, Thomas M. Congdon, Kevin L. Martin.
Application Number | 20130161031 13/333013 |
Document ID | / |
Family ID | 48653437 |
Filed Date | 2013-06-27 |
United States Patent
Application |
20130161031 |
Kind Code |
A1 |
Biggs; Nick W. ; et
al. |
June 27, 2013 |
DOZING BLADE ASSEMBLY, CUTTER AND DOZING METHOD
Abstract
A dozing blade assembly includes a dozing blade, and a cutter
mounted to the dozing blade. The cutter includes a compound digging
face extending between a proximal edge and a distal edge. The
compound digging face has a steeply oriented center segment, and
shallowly oriented outer segments, for balancing downward
penetration with forward pushability during moving the dozing blade
assembly through material of a substrate.
Inventors: |
Biggs; Nick W.;
(Princeville, IL) ; Congdon; Thomas M.; (Dunlap,
IL) ; Martin; Kevin L.; (Washburn, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Biggs; Nick W.
Congdon; Thomas M.
Martin; Kevin L. |
Princeville
Dunlap
Washburn |
IL
IL
IL |
US
US
US |
|
|
Assignee: |
Caterpillar, Inc.
Peoria
IL
|
Family ID: |
48653437 |
Appl. No.: |
13/333013 |
Filed: |
December 21, 2011 |
Current U.S.
Class: |
172/1 ;
172/701.1 |
Current CPC
Class: |
E02F 3/7618 20130101;
E02F 3/8152 20130101 |
Class at
Publication: |
172/1 ;
172/701.1 |
International
Class: |
E02F 3/815 20060101
E02F003/815 |
Claims
1. A dozing blade assembly for a tractor comprising: a dozing blade
including a first and a second outboard wing, a forwardly located
moldboard extending between the first and second outboard wings,
and a plurality of rearwardly located push-arm mounts, for coupling
the dozing blade assembly with push-arms of the tractor; the dozing
blade defining a vertical axis and further including an upper and a
lower edge, and a material molding surface located in part on the
moldboard, and in part on each of the first and second outboard
wings, the material molding surface having a concave vertical
profile extending between the upper and lower edges, and a concave
horizontal profile; a cutter mounted to the dozing blade and having
a proximal edge positioned adjacent the material molding surface, a
distal edge, and a compound digging face extending between the
proximal edge and the distal edge; and the compound digging face
having a center segment oriented at a steep angle of vertical
inclination relative to a horizontal plane located beneath the
dozing blade and oriented normal to the vertical axis, and a first
and a second outer segment adjoining the center segment and each
being oriented at a shallow angle relative to the horizontal
plane.
2. The assembly of claim 1 wherein the cutter includes an elongate
multi-piece body including a middle body section having the center
segment of the compound digging face located thereon, and a first
and a second outer body section having the first and second outer
segments of the compound digging face, respectively, located
thereon.
3. The assembly of claim 2 wherein a length of the middle body
section is from one third to two thirds of a sum of the length of
the middle, first, and second body sections, and wherein a width of
the middle body section is less than widths of each of the first
and second body sections.
4. The assembly of claim 3 wherein: each of the middle, first, and
second body sections defines a plurality of bolting holes passing
therethrough, and further comprising a plurality of bolts extending
through the plurality of bolting holes and coupling the cutter to
the dozing blade; and the dozing blade further includes a planar
mounting surface extending along the lower edge between the first
and second outboard wings, and wherein each of the middle, first,
and second body sections includes a back mounting face contacting
the planar mounting surface.
5. The assembly of claim 4 wherein the middle body section defines
a first face angle between the center segment of the digging face
and the corresponding back mounting face, and each of the first and
second body sections defines a second, different face angle between
the respective first and second outer segments of the digging face
and the corresponding back mounting faces.
6. The assembly of claim 5 wherein a difference between the second
face angle and the first face angle is about 30.degree., or
less.
7. The assembly of claim 6 wherein each of the middle, first, and
second body sections includes a distally narrowing taper having the
distal edge of the cutter located thereon.
8. The assembly of claim 2 wherein the cutter further includes a
first end plate and a second end plate aligned with the first and
second outboard wings, respectively, and wherein the middle, first,
and second body sections extend between the first and second end
plates and are aligned with the moldboard.
9. A cutter for a dozing blade assembly comprising: an elongate
multi-piece body having a plurality of body sections each defining
a plurality of bolting holes communicating between a front digging
face and a back mounting face, and being configured to receive a
plurality of bolts for mounting the plurality of body sections in a
service configuration upon a planar mounting surface of a dozing
blade coupled with a tractor; the plurality of body sections each
including a proximal edge and a distal edge, and a length extending
parallel the proximal and distal edges, and further defining a face
angle between the corresponding digging and mounting faces in a
plane oriented normal to the corresponding length; the plurality of
body sections further including a middle body section, and a first
and a second outer body section, and the length of the middle body
section being from one-third to two-thirds of a sum of the lengths
of the middle, first, and second body sections; and the face angle
of the middle body section being different from the face angle of
each of the first and second body sections, such that in the
service configuration the digging face of the middle body section
is more steeply inclined than the digging face of the first and
second body sections relative to an underlying substrate.
10. The cutter of claim 9 wherein a difference between the face
angle of the middle body section and the face angle of the first
and second body sections is about 30.degree. or less.
11. The cutter of claim 10 wherein the difference between the face
angles is equal to about 20.degree., and wherein the length of the
middle section is from 2 feet to twelve feet.
12. The cutter of claim 10 wherein one of the middle, first, and
second body sections, includes parallel digging and mounting
faces.
13. The cutter of claim 12 wherein the middle body section includes
the parallel digging and mounting faces.
14. The cutter of claim 11 wherein each of the middle, first, and
second body sections, includes a distally narrowing taper, such
that the corresponding distal edge is located upon the distally
narrowing taper.
15. The cutter of claim 14 further comprising a first and a second
end plate positionable outboard of the first and second body
sections, in the service configuration.
16. The cutter of claim 15 wherein the first end plate and the
second end plate each include a planar front digging face and a
planar back mounting face.
17. A method of dozing with a tractor comprising the steps of:
moving the tractor in a forward direction such that a cutter
mounted to a dozing blade of the tractor advances through material
of a substrate extending horizontally beneath the tractor; inducing
failure of the substrate during the advancement via a middle
section of the cutter steeply oriented relative to a horizontal
plane, and via outer sections of the cutter shallowly oriented
relative to the horizontal plane; and sliding material loosened
from the substrate via the induced failure in an upward direction
across a material molding surface of the dozing blade.
18. The method of claim 17 wherein the steeply oriented middle
section has a length which is from one-third to two-thirds of a sum
of lengths of the middle and outer sections.
19. The method of claim 18 wherein the middle section has a front
digging face oriented at an angle relative to a horizontal plane
defined by the substrate which is from about 40.degree. to about
55.degree., and the outer sections have front digging faces
oriented at shallow angles relative to the horizontal plane which
are from about 25.degree. to about 45.degree..
20. The method of claim 19 wherein the step of inducing further
includes shattering the substrate, and further comprising a step of
pushing the loosened material in a forward direction via the
movement of the tractor such that a slot is formed in the
substrate.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to a dozing blade
assembly for a tractor, and relates more particularly to dozing
material via a dozing blade assembly having a cutter with a steeply
oriented center section and shallowly oriented outer sections.
BACKGROUND
[0002] Tractors equipped with dozing blades are used for a great
many different purposes. Applications which will be familiar to
most include pushing loose material such as landfill trash,
construction debris, and soil about a worksite. Such dozing
activities are indispensable to forestry, waste handling, building
construction, and light to medium civil engineering. Small to
mid-sized tractors are commonly used in these industries.
[0003] Dozing is also an integral part of larger scale activities
such as mining and major civil engineering projects. In these
contexts, rather than pushing loose material across a surface,
tractors equipped with dozing blades are often used to dig material
from a substrate. In the case of rocky terrain, commonly
encountered in opencast mines, or where substrate materials
otherwise have a high structural integrity, quite large and
powerful machines equipped with rugged dozing blades are often
required. These and analogous activities are generally referred to
as "production dozing." In production dozing, a tractor equipped
with a heavy-duty dozing blade is typically driven across, and
through, a substrate such that a cutting edge of the dozing blade
penetrates downward and forward through the material of the
substrate, overcoming the structural integrity of the material, and
causing it to fail. In large scale surface mining activities, a
tractor, typically equipped with ground engaging tracks, may make
successive passes across an area where surface material is to be
removed, forming a slot in the substrate in each pass. Due to the
harsh environment, frequent repair, replacement, and servicing of
the equipment is often necessary. Moreover, to maximize
productivity it is often desirable to employ machine operators who
are highly skilled. Unskilled operators have been observed to
manipulate a dozing blade or otherwise operate a tractor such that
the tractor stalls while attempting to form a slot in a substrate.
In other instances, rather than stalling the tractor, unskilled
operators can sometimes cut a slot that is too shallow than what is
theoretically possible, or even skim the dozing blade across a
surface of the substrate without loosening any substantial amount
of material over at least a portion of a given pass. Stalling the
machine, or removing too little material, understandably impacts
efficiency. For these and other reasons, there remains a premium in
the pertinent industries on sophisticated equipment design and
operation, as well as operator skill.
[0004] U.S. Pat. No. 3,238,648 to D. E. Cobb et al. is directed to
a bulldozer with a stinger bit, for the apparent purpose of
enabling a reasonably deep cut through hard material without
overtaxing the tractor engine and tractive ability. These goals are
apparently achieved by making the stinger bit adjustable or
retractable, such that it can be used to ease initial penetration.
This design would apparently enable a normal use of the full width
of the blade, and an alternative use with the stinger bit extended.
While Cobb et al. may have provided advantages over the state of
the art at that time, there remains ample room for improvement.
Moreover, the features necessary to enable the functionality of the
stinger bit, such as hydraulic actuators and the like, can add
non-trivial expense, complexity and maintenance requirements to the
machine.
SUMMARY
[0005] In one aspect, a dozing blade assembly for a tractor
includes a dozing blade having a first and a second outboard wing,
a forwardly located moldboard extending between the first and
second outboard wings, and a plurality of rearwardly located
push-arm mounts, for coupling the dozing blade assembly with
push-arms of the tractor. The dozing blade further includes an
upper and a lower edge, and a material molding surface located in
part on the moldboard, and in part on each of the first and second
outboard wings, the material molding surface having a concave
vertical profile extending between the upper and lower edges, and a
concave horizontal profile. The assembly further includes a cutter
mounted to the dozing blade and having a proximal edge positioned
adjacent the material molding surface, a distal edge, and a
compound digging face extending between the proximal edge and the
distal edge. The compound digging face has a center segment
oriented at a steep angle relative to a horizontal plane, and a
first and a second outer segment adjoining the center segment and
each being oriented at a shallow angle relative to the horizontal
plane.
[0006] In another aspect, a cutter for a dozing blade assembly
includes an elongate multi-piece body having a plurality of body
sections each defining a plurality of bolting holes communicating
between a front digging face and a back mounting face, and being
configured to receive a plurality of bolts for mounting the
plurality of body sections in a service configuration upon a planar
mounting surface of a dozing blade coupled with a tractor. The
plurality of body sections each include a proximal edge and a
distal edge, and a length extending parallel the proximal and
distal edges, and further defining a face angle between the
corresponding digging and mounting faces in a plane oriented normal
to the corresponding length. The plurality of body sections further
include a middle body section, and a first and a second outer body
section, and the length of the middle body section is from
one-third to two-thirds of a sum of the lengths of the middle,
first, and second body sections. The face angle of the middle body
section is different from the face angle of each of the first and
second body sections, such that in the service configuration the
digging face of the middle body section is more steeply inclined
than the digging face of the first and second body sections
relative to an underlying substrate.
[0007] In still another aspect, a method of dozing with a tractor
includes moving the tractor in a forward direction such that a
cutter mounted to a dozing blade of the tractor advances through
material of a substrate. The method further includes inducing
failure of the substrate during the advancement, via a steeply
oriented middle section and shallowly oriented outer sections of
the cutter, and sliding material loosened from the substrate via
the induced failure in an upward direction across a material
molding surface of the dozing blade.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a diagrammatic view of a dozing blade assembly
having a cutter, according to one embodiment;
[0009] FIG. 2 is a top view of the dozing blade assembly of FIG.
1;
[0010] FIG. 3 is a top view of a cutter, according to another
embodiment;
[0011] FIG. 4 is a top view of a cutter, according to yet another
embodiment;
[0012] FIG. 5 is a diagrammatic view of a cutter, prepared for
shipping, according to one embodiment;
[0013] FIG. 6 is an end view of two sections of the cutter of FIG.
5;
[0014] FIG. 7 is an end view of two sections of a cutter, according
to another embodiment;
[0015] FIG. 8 is an end view of two sections of a cutter according
to yet another embodiment;
[0016] FIG. 9 is an enlarged end view of one section of the cutter
of FIGS. 5 and 6;
[0017] FIG. 10 is a side diagrammatic view of a tractor at one
stage of a dozing process, according to one embodiment;
[0018] FIG. 11 is a side diagrammatic view of the tractor of FIG.
10, at another stage of the dozing process; and
[0019] FIG. 12 is a bar chart illustrating certain dozing
parameters for a dozing blade assembly according to the present
disclosure, in comparison with other designs.
DETAILED DESCRIPTION
[0020] Referring to FIG. 1, there is shown a dozing blade assembly
10 for a tractor, according to one embodiment. Assembly 10 may
include a dozing blade 12 having a front side 13, a back side 19, a
first outboard wing 14 and a second outboard wing 16. A forwardly
located moldboard 18 extends between first and second outboard
wings 14 and 16. Blade 12 further includes a first side plate 15
and a second side plate 17 positioned outboard of and coupled to
wings 14 and 16. A plurality of rearwardly located push-arm mounts
20, one of which is diagrammatically shown, are positioned at back
side 19, for coupling assembly 10 with push-arms of a tractor. A
plurality of tilt actuator connectors 21 are likewise positioned at
back side 31, in a conventional manner. Blade 12 further includes
an upper edge 22 and a lower edge 24. A material molding surface 26
is located in part on moldboard 18, and in part on each of wings 14
and 16 and extends from side plate 15 to side plate 17. Material
molding surface 26 has a concave vertical profile extending between
upper and lower edges 22 and 24, and a concave horizontal profile.
Blade 12 may further include a first lifting eye 31 and a second
lifting eye 33 located upon, within or proximate side plates 15 and
17, near back side 19, for coupling blade 12 with a tractor in a
conventional manner. A plurality of lift actuator connectors 27 are
positioned along upper edge 22. Although it is contemplated that
assembly 10 may be configured for lifting and lowering, tilting,
and possibly pivoting when coupled with the tractor, the present
disclosure is not thereby limited. Blade 12 defines a generally
vertical axis 28, located mid-way between connectors 27. As will be
further apparent from the following description, assembly 10 is
uniquely configured for balancing the relative ease with which
assembly 10 penetrates material of a substrate with the relative
ease with which assembly 10 may be pushed forward through the
substrate, to optimize dozing efficiency.
[0021] To this end, assembly 10 may further include a cutter 30
mounted to blade 12 and having a trailing or proximal edge 32
positioned adjacent material molding surface 26, and a leading or
distal edge 34. Cutter 30 may further include a compound digging
face 36 extending between proximal edge 32 and distal edge 34.
Digging face 36 includes a center segment 38 oriented at a steep
angle relative to a horizontal plane, for example the plane of the
page in FIG. 1 which is approximately normal to axis 28. Digging
face 36 may further include a first outer segment 40 and a second
outer segment 42 adjoining center segment 38. Each of segments 40
and 42 may be oriented at a shallow angle relative to the
horizontal plane. The differently oriented digging faces, or
digging face segments, enable balancing downward penetrability with
forward pushability of assembly 10 through material of a substrate.
The terms "steep" and " shallow" are used herein in comparison with
one another, and relative to the horizontal plane. The horizontal
plane may be self-defined by assembly 10 based upon its service
orientations. If assembly 10 were rested upon the ground on front
side 13 or back side 19, the "horizontal" plane would extend
transverse to the ground surface. Where rested approximately as
shown in FIG. 1, the horizontal plane is substantially the same as
a horizontal plane that would be defined by the underlying
substrate upon which assembly 10 is resting. Horizontal and
vertical directions or orientations may also be understood in
reference to the vertical and horizontal terms used in describing
the concave profiles of surface 26.
[0022] Cutter 30 may include an elongate, multi-piece body 43
having a middle body section 44, a first outer body section 46 and
a second outer body section 48. Middle body section 44 may have
center segment 38 of digging face 36 located thereon, whereas first
and second outer body sections 46 and 48 may have first and second
outer segments 40 and 42, respectively, of digging face 36 located
thereon. Each of segments 38, 40 and 42 might also be understood
independently as a "digging face," but are referred to herein as
segments for ease of description. Cutter 30 may still further
include a first end plate 84 and a second end plate 86 aligned with
first and second outboard wings 14 and 16, respectively. Middle
body section 44 and outer body sections 46 and 48 may extend
between first and second end plates 84 and 86 and are aligned with
moldboard 18. End plates 84 and 86 may have the form of end "bits"
in certain embodiments, comprising a casting or forging having a
shape other than a simple plate. The present disclosure is not
limited to any particular end plate or bit configuration, and
different styles may suit different dozing applications.
[0023] Referring now to FIG. 2, there is shown a top view of
assembly 10, in partial cut-away where body section 42, end plate
86 and part of body section 44 are not shown, and illustrating a
planar mounting surface 66 of blade 12. Another planar mounting
surface (not numbered) is shown adjacent surface 66, for mounting
end plate 86. The portions of blade 12 obscured by cutter 30 in
FIG. 2 are configured similarly to those visible. Also shown in
FIG. 2 are a plurality of bolts 64 extending through a bolting
holes 62. In a practical implementation strategy, each of middle
body section 44 and first and second outer body sections 46 and 48
may define a plurality of bolting holes 62 passing therethrough,
such that bolts 64 may couple cutter 30 to blade 12, in particular
being received in registering bolting holes in blade 12. End plates
84 and 86 may similarly define a plurality of bolting holes for
analogous purposes.
[0024] Referring now to FIG. 3, there is shown a cutter 130
according to another embodiment, and having a middle body section
144, outer body sections 146 and 148, and end plates 184 and 186.
Each of the body sections may be part of an elongate multi-piece
body 143, similar to elongate body 43, but differing with respect
to the relative lengths of the respective body sections. It will be
noted that a length of middle body section 144 relative to sections
146 and 148 is relatively less than the length of middle body
section 44 relative to sections 46 and 48 in the foregoing
embodiment. Thus, the middle section of a cutter according to the
present disclosure may be either longer or shorter than the
corresponding outer sections. FIG. 4 illustrates yet another
embodiment of a cutter 230, including an elongate body 243, having
a middle body section 244, outer body sections 246 and 248, and end
plates 284 and 286. Rather than a multi-piece body, cutter 230 is
configured as a single piece body. Cutter 230 also includes first
and second transition sections 249 extending between middle body
section 244 and outer body sections 246 and 248. It is contemplated
that many embodiments according to the present disclosure may be
configured as retrofit kits, where individual body sections are
coupled with a mounting surface of a dozing blade in place of a
conventionally designed cutter. This is so primarily because
cutters used in dozing blades may be quite heavy, and a
single-piece version could be more difficult to handle and install,
as well as manufacture. It is nevertheless contemplated that a
single-piece body designs may fall within the scope of the present
disclosure.
[0025] Referring now also to FIG. 5, there is shown cutter 30
disassembled and packaged upon a pallet 300 via securing straps or
the like 302, as it might appear where cutter 30 is prepared to be
shipped for service. As noted above, lengths of certain of the
components of cutter 30, and other embodiments contemplated herein,
may be varied from the relative lengths and aspect ratios shown in
the embodiments of FIGS. 1-4. In FIG. 5, reference numeral 50
indicates a length of middle body section 44 extending from one end
to an opposite end thereof, and generally parallel edges 32 and 34.
Length 50 may be from two feet to twelve feet, and in certain
embodiments from four feet to eight feet. Reference numeral 54
indicates a length of outer section 48. Outer sections 46 and 48
may, in at least most embodiments, be equal in length and width to
one another. A width of middle body section 44 is indicated with
reference numeral 56, whereas a width of outer body section 48 is
indicated with reference numeral 60. Each of widths 56 and 60 may
be defined as the width of the respective digging face segment in a
direction normal to the corresponding lengths. In a practical
implementation strategy, length 50 may be from one-third to
two-thirds of a sum of lengths 50, 54, and the corresponding length
of section 46. Width 56 may be less than width 60, and length 50
may be greater than width 56 by a factor of four or greater.
[0026] As noted above, dozing blade 12 may include planar mounting
surface 66 extending along lower edge 24 between wings 14 and 16.
Each of middle, first, and second body sections 44, 46 and 48 may
include a back mounting face 68, 70 and 72, respectively, which
contacts mounting surface 66 when cutter 30 is assembled in a
service configuration upon blade 12 as shown in FIG. 1. Each of
back mounting faces 68, 70 and 72 may be planar. It may also be
noted from FIG. 5 that each of body sections 44, 46 and 48 may
define a generally polygonal cross-section, as may end plates 84
and 86. In the illustrated embodiment, body section 44 and end
plates 84 and 86 may each be formed from a flat piece of rolled
steel, whereas outer sections 46 and 48 may be cast or forged, for
instance. In the FIG. 5 embodiments, end plates 84 and 86 have
parallel front digging and back mounting faces. Also illustrated in
FIG. 5 are bolting holes 62. It may be noted that bolting holes 62
may be arranged in a pattern defining a straight line extending
generally parallel edges 32 and 34 of cutter 30, along each of body
sections 44, 46 and 48. Bolting holes 62 may be located relatively
closer to proximal edge 32 than to distal edge 34, although the
present disclosure is not thereby limited. Bolting holes 62 formed
in end plates 84 and 86 may be arranged in a similar pattern.
[0027] Turning now to FIG. 6, there is shown an end view of body
section 44 and body section 46 as they might appear when back
mounting faces 68 and 70 are positioned in a common plane, such as
when resting upon pallet 300 or a horizontal ground surface.
Although body section 48 is not shown in FIG. 6, since it may be
substantially identical to body section 46, or a mirror image
thereof, the present description should be understood to similarly
apply. Body section 44 may define a first face angle 74 between
center segment 38 of digging face 36 and back mounting face 68, the
face angle lying in a plane normal to length 50. Body section 46
may define a second face angle 76 between outer segment 40 of
digging face 36 and back mounting face 70, in an analogous plane.
Second face angle 76 is greater than first face angle 74 in the
FIG. 6 embodiment. In a practical implementation strategy, a
difference between second face angle 76 and first face angle 74 may
be about 30.degree., or less, and may be equal to about 20.degree.
in certain embodiments. In the FIG. 6 embodiment, the respective
segments of digging face 36 and mounting face 70 upon section 44
are parallel. In other embodiments, parallel digging and mounting
face segments are instead located on the outer body sections, and
the middle body section may include non-parallel digging and
mounting faces, as discussed below.
[0028] Referring to FIG. 7, there is shown yet another embodiment
of a cutter 430 according to the present disclosure. Cutter 430
includes a middle body section 444 and an outer body section 446,
and will be understood to include another outer body section which
is not shown in FIG. 7. In cutter 430, middle body section 444
defines a first face angle 474, whereas outer body section 446
defines a second face angle 476. It may be noted that in cutter 30,
as shown in FIG. 6, middle body section 44 is flat, such that angle
74 is equal to approximately zero. In such an embodiment, angle 76
might be between zero and 30.degree.. In the embodiment of FIG. 7,
analogously defined first face angle 474 may be greater than zero,
and second face angle 476 may be approximately zero. FIG. 8
illustrates yet another cutter 530, in which neither of a middle
section 544 nor an outer section 546 defines a face angle equal to
zero. Instead, a first face angle 574 defined by middle section 544
may have a first size, and a second face angle 576 may have a
second, greater size which is between the value of face angle 574
and face angle 574 plus 30.degree..
[0029] As further discussed below, certain advantageous properties
of the present disclosure relate to how steeply the different
sections of a cutter for a dozing blade assembly are oriented
relative to the ground. Since dozing blades themselves may have
varying geometry, the values of the various face angles discussed
herein can vary substantially. While relatively small differences
between face angles are contemplated herein, it should be noted
that a difference between face angles of a middle body section and
outer body sections which results from variations within
manufacturing tolerances would not satisfy the intended
understanding of "steep" versus "shallow." As noted above, the
second face angle may be different from the first face angle, such
that in a service configuration of cutter 30 and the other cutter
embodiments contemplated herein, the digging face upon the middle
body section is more steeply inclined than the digging face upon
the outer body sections relative to an underlying substrate, and
more particularly relative to a horizontal plane defined by the
underlying substrate such as a plane of the ground surface.
Typically, either middle body section 44, or both of outer body
sections 46, will be flat such that the corresponding face angle is
zero, although as illustrated in FIG. 8 alternatives are
contemplated. Except where a dozing blade mounting surface is
purpose-built to obtain different effective face angles in service,
or some other modification, such as wedge-shaped shims, is used,
body sections 44, 46, 48 will not all be flat and define face
angles of zero.
[0030] Referring now to FIG. 9, there is shown an enlarged view of
middle body section 44, and illustrating a relief surface 58 which
is part of distal edge 34. It has been discovered that a relieved
profile such as that imparted by forming relief surface 58 can
assist in achieving initial penetration into a substrate, rather
than a tendency for the cutter to ski along the surface of the
substrate. Relief surface may extend a distance between faces 38
and 68 which is up to about 50% of a thickness between faces 38 and
6. Other sections of cutter 30 may have similar relief surfaces.
Returning to FIG. 6, it may be noted that middle body section 44
includes a distally narrowing taper 78, and that distal edge 34 is
located upon the distally narrowing taper 78. Outer body section 46
also includes a distally narrowing taper 80, and the corresponding
portion of distal edge 34 is also located on the distally narrowing
taper 80.
INDUSTRIAL APPLICABILITY
[0031] Referring to FIGS. 10 and 11, there is shown a track-type
tractor 100 having a track 102 coupled with a frame 106. A dozing
blade assembly 10 is coupled with a set of push-arms 104 of tractor
100, and a tilt actuator 108. No lift or pivot actuators are shown,
although tractor 100 might be thusly equipped. In FIG. 10, dozing
blade assembly 10 is shown in a sectioned view as it might appear
where the section plane passes vertically through assembly 10
approximately at a horizontal centerpoint, such that middle body
section 44 is visible within a slot 103 being formed in a substrate
101. In FIG. 11, assembly 10 is shown sectioned as it might appear
where the section plane passes vertically through assembly 10 such
that outer body section 46 is visible. Digging face segment 38 of
middle body section 44 is oriented at a steep angle 75 relative to
a horizontal plane, for example from about 40.degree. to about
55.degree.. Digging face segment 40 of outer body section 46 is
more shallowly oriented relative to the horizontal plane at an
angle 77 which is from about 25.degree. to about 45.degree..
[0032] It will be recalled that face angles 74 and 76 may differ
from one another by about 30.degree. or less. Thus, in an
embodiment where angle 77 is about 25.degree. and angle 75 is about
55.degree., at the respective upper and lower extremes of the
disclosed ranges, the difference between face angles 74 and 76 may
be about 30.degree.. Other values for angles 77 and 75 between the
extremes of the described ranges may yield differences between face
angles 74 and 76 which are less than 30.degree.. While the
disclosed ranges for angles 77 and 75 overlap, those skilled in the
art will appreciate in view of the other teachings herein that face
angles 74 and 76 will typically not be equal, or otherwise selected
such that the steeper versus shallower orientations of the
respective digging face segments in service are not obtained. The
term "about" is used herein in the context of rounding to a
consistent number of significant digits. Accordingly, "about
40.degree." means from 35.degree. to 44.degree., "about 35.degree."
means from 34.5.degree. to 35.4.degree., and so on.
[0033] It will be recalled that the different orientations of
digging face segment 38 versus digging face segments 40 and 42 may
be configured to balance downward penetrability with forward
pushability of cutter 30, and thus dozing blade assembly 10,
through material of a substrate. To this end, in FIG. 10, a
relatively small vertical arrow 97 is shown, versus a relatively
large horizontal arrow 99. The difference in sizes of arrows 97 and
99 may be understood to represent the relative ease with which body
section 44 can be urged through material of substrate 101 in the
respective directions. In FIG. 11, vertical arrow 97 is relatively
large, whereas horizontal arrow 99 is relatively small,
representing the relative ease with which section 46 may be urged
through material of substrate 101 in the respective directions.
Another way to understand the principles illustrated in FIGS. 10
and 11 is that body section 44 may be urged vertically through
material of substrate 101 relatively easily, but with more
difficulty urged horizontally through the material. In contrast,
section 46 may be more difficult to urge in a vertical direction,
but easier to urge in a horizontal direction.
[0034] As tractor 100 is moved in a generally forward direction,
left to right in FIGS. 10 and 11, slot 103 may be formed in
substrate 101, by inducing failure of substrate 101, and such that
material loosened via the induced failure flows in a generally
upward direction across the material molding surface of the dozing
blade, and is ultimately pushed in a forward direction via the
movement of tractor 100. This will generally occur, based on the
differently oriented digging face segments of cutter 30, and
without any adjustment to a tilt angle of assembly 10, such that
the likelihood of stalling or skimming the dozing blade and/or
tractor is reduced. As noted above, angle 75 may be from about
40.degree. to 55.degree., and angle 77 may be from about 25.degree.
to about 45.degree.. In a further practical implementation
strategy, angle 75 may be equal to about 53.degree., and angle 77
may be equal to about 30.degree.. In forming slot 103, failure of
substrate 101 may be induced via shattering, in contrast to other
digging techniques such as scraping, in which a ribbon of material
is sliced off.
[0035] Referring now to FIG. 12, there is shown data via a bar
chart reflecting payload, specific energy, and gross energy for a
first dozing blade assembly 1, a second dozing blade assembly 2,
and a third dozing blade assembly 3. The data in FIG. 12 are full
scale data derived from scale model laboratory testing. Dozing
blade assemblies 1 and 2 represent dozing blades having a cutter
with a design different from the designs of the present disclosure,
and in particular having a middle body section and outer body
sections which are not differently oriented, in other words
extending straight across the front of the dozing blade assembly
and having digging faces in a common plane. Assembly 3 represents
data which might be expected to be obtained with a dozing blade
having the differently oriented digging face segments, i.e. steep
middle and shallow outer, of the present disclosure. Each of
assemblies 1, 2 and 3 was passed through material having scaled
down soil properties until the maximum payload capacity was
obtained. The units shown on the left side of FIG. 12 represent
payload in kilograms of material. It may be noted that a payload
with dozing blade assembly 1 is slightly greater than 10,000
kilograms, whereas a payload with dozing blade assembly 2 is
slightly more than 11,000 kilograms. A payload using dozing blade
assembly 3 is approximately 15,000 kilograms, representing an
increase in payload of at least 25% over the other designs. Gross
energy is generally less with dozing blade assembly 3 than with
either of dozing blade assemblies 1 and 2. With regard to specific
energy, which includes a quantity of energy consumed per unit of
material moved such as kilojoules per kilogram, and is perhaps the
most useful metric of production dozing efficiency, it may be noted
that dozing blade assembly 3 has a specific energy of about 0.225
as shown on the right side of FIG. 12, whereas dozing blade
assemblies 1 and 2 each have a specific energy greater than 0.3
units of energy per unit mass of material, representing an
efficiency advantage with the present design of at least 25%, and
which is expected in certain instances to be at least 30%.
[0036] As discussed above, in earlier strategies production was
often limited by either too great a tendency of the cutter of the
dozing blade assembly to penetrate downward into material of a
substrate, ultimately stalling the dozing blade assembly and
tractor, or downward penetration was relatively more difficult and
forward pushability was relatively easier, sometimes resulting in
skimming the dozing blade assembly or cutting at too shallow a
depth. In either case, it was typically necessary to perform a
greater number of material removal passes, back up and repeat a
pass when the tractor stalled, or simply accept the relatively low
efficiency of the overall production dozing process. While
operators may be able to manipulate the blade during dozing to
lessen the likelihood of these problems, not all operators are
sufficiently skilled to do this, nor are all dozing blades and
tractors equipped to enable such techniques.
[0037] The present disclosure thus reflects the insight that the
relative ease with which a cutter can be urged through material
vertically versus horizontally can be balanced such that
penetrability and pushability are optimized, to in turn optimize
production. This is achieved without the need for adjustable and
relatively complex systems such as Cobb, discussed above. While
certain other known strategies claim to achieve increased
production dozing efficiency by way of specialized blade and/or
moldboard configurations, the present disclosure achieves increased
efficiency by way of features of the cutter, and is thus applicable
to many different types of blades.
[0038] From the foregoing description, it will further be
appreciated that many combinations of cutter body section geometry
can yield a cutter for a dozing blade assembly having the desired
characteristics. The specific geometry chosen, such as the size of
the face angles of the respective body sections may be tailored to
suit the geometry of the mounting face on the dozing blade to which
the cutter is to be mounted. Various parameters of a cutter may
also be tailored based upon the intended service applications. For
very tough substrates, such as rock, the middle section of the
cutter may be designed such that the center section of the digging
face is both relatively steep with respect to an underlying
substrate and relatively long. For very soft substrates, such as
certain sandy soils, the middle section may be designed such that
the center segment of the digging face is both relatively shallow
and relatively short. For substrates of intermediate toughness, the
inclination of the center segment may be medium, as may its
length.
[0039] It should further be appreciated that body section length
and digging face inclination are factors which can be independently
varied. Thus, for a given steepness of the center digging face
segment, a relatively longer length of the middle body section can
yield greater penetrability and lesser pushability, whereas a
relatively shorter length can yield lesser penetrability and
greater pushability. As noted above, a length of the middle body
section which is from one-third to two-thirds of the sum of the
lengths of the middle and outer body sections, may be sufficient to
cause the interaction of the cutter with material of a substrate to
be determined by both the middle body section and the outer body
sections. Where the length of the middle body section is less than
one-third of the sum of the lengths of the three sections, the
balance between pushability and penetrability of the cutter, may be
determined too much by the outer body sections. Where the length of
the middle body section is greater than two-thirds of the sum of
the lengths of the three sections, that balance may be determined
too much by the middle body section. Another way to understand
these principles is that the middle body section should not be made
so short relative to the other body sections that it has only a
minimal effect on the dozing behavior of the cutter, nor so long
that the middle body section overwhelmingly determines the behavior
of the cutter. With regard to varying steepness of the digging face
on the middle body section, if made steeper than the generally
range disclosed herein, the reduced pushability may be problematic,
whereas if made too shallow, the cutter may fail to penetrate. As
to the difference in inclination between the respective digging
face segments in the service configuration, if made too large the
cutter may have too much overall resistance to moving through a
substrate, and thus neither optimum pushability nor optimum
penetrability.
[0040] The present description is for illustrative purposes only,
and should not be construed to narrow the breadth of the present
disclosure in any way. Thus, those skilled in the art will
appreciate that various modifications might be made to the
presently disclosed embodiments without departing from the full and
fair scope and spirit of the present disclosure. Other aspects,
features and advantages will be apparent upon an examination of the
attached drawings and appended claims.
* * * * *