DOZING BLADE ASSEMBLY, CUTTER AND DOZING METHOD
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.
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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.
BACKGROUNDTractors 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.
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.
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.
SUMMARYIn 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.
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.
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.
Referring to
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
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.
Referring now to
Referring now to
Referring now also to
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
Turning now to
Referring to
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
Referring now to
Referring to
It will be recalled that face angles 74 and 76 may differ from one another by about 30° or less. Thus, in an embodiment where angle 77 is about 25° and angle 75 is about 55°, at the respective upper and lower extremes of the disclosed ranges, the difference between face angles 74 and 76 may be about 30°. 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°. 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°” means from 35° to 44°, “about 35°” means from 34.5° to 35.4°, and so on.
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
As tractor 100 is moved in a generally forward direction, left to right in
Referring now to
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.
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.
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.
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.
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.
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°, 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° or less.
11. The cutter of claim 10 wherein the difference between the face angles is equal to about 20°, 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° to about 55°, and the outer sections have front digging faces oriented at shallow angles relative to the horizontal plane which are from about 25° to about 45°.
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.
Type: Application
Filed: Dec 21, 2011
Publication Date: Jun 27, 2013
Applicant: Caterpillar, Inc. (Peoria, IL)
Inventors: Nick W. Biggs (Princeville, IL), Thomas M. Congdon (Dunlap, IL), Kevin L. Martin (Washburn, IL)
Application Number: 13/333,013
International Classification: E02F 3/815 (20060101);