Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
EXCAVATING IMPLEMENT
Technical Field
The present invention relates to excavating implements and more
particularly to implement blades.
Background Art
Many conventional excavating devices are provided with buckets or blades
(hereafter generally termed "bucket's for excavation purposes including
digging,
scraping, cleaning, and demolition. Such buckets are used tv push, fracture
and
to shovel materials. The leading edge of a bucket is typically formed as a
beveled or non-beveled straight edge that extends across the bucket bottom and
is the first part of the bucket to engage the material being excavated. It is
well understood that the leading edge is subjected to heavy wear and stress
factors.
Some manufactures produce replacement edges for buckets with leading
edges that are similar in configuration to the original, straight line bucket
leading
edge. Such attachments are intended to reduce wear on the original leading
edges. This would be an advantage except for the fact that the straight
cutting
edges do not function efficiently for excavation and clean-up operations, nor
will
20 they operate efficiently to break up or shatter the materials being
excavated.
Further, straight line leading edges tend to ride over materials on a hard
surface,
thus leaving debris which slides under the blade.
Toothed attachments of various sons have been produced which may be
mounted to the top or bottom surfaces of conventional buckets or blades. They
25 have teeth extending forwardly of the original edge. The forwardly
projecting
teeth are used for breaking up or shattering materials ahead of the bucket or
blade. These attachments may improve operations but are use specific and often
do not function effectively for clean-up operations for the same reasons
stated
above .
3o A long felt need has remained for a bucket with a leading edge that will
function efficiently for numerous uses.
It is therefore one aspect of the present invention to provide an
excavating implement that will function to reduce or substantially eliminate
wear
of a bucket leading edge, while providing structure that will improve
excavation
35 efficiency over a wide range of uses.
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It is a further aspect of the present invention to provide such an
excavating implement that may be adapted to fit numerous bucket
configurations.
Still another aspect of the present invention is to provide such an
excavating implement that will effectively reduce horsepower requirements and
thereby improve overall operating efficiency of the implement power source.
Yet still another aspect of the present invention is to provide such an
excavating implement that may be easily and quickly mounted to existing
excavator buckets.
These and still further aspects and advantages of the present invention will
become apparent from the following description which, taken with the appended
drawings, disclose the best mode presently known to the Applicants for
carrying
out the invention.
Brief Description of the Drawings
Fig. 1 is a perspective view of an excavator with a bucket and a
preferred form of the present implement at the bucket leading edge;
Fig. 2 is a perspective view of a preferred excavating implement for
mounting as a retrofit to existing buckets;
Fig. 3 is a top plan view of the excavating implement shown in Fig. 2;
Fig. 4 is an enlarged fragmentary view of the area encircled by dashed
20 lines and identified by the number 4 in Fig. 3;
Fig. 5 is a bottom plan view of the excavating implement shown in Fig.
2;
Fig. 6 is an enlarged end elevation view thereof;
Fig. 7 is an enlarged sectional view taken substantially along line 7-7 in
25 Fig. 3;
Fig. 8 is an enlarged fragment view of the area encircled by dashed lines
and identified by the number 8 in Fig. 7;
Fig. 9 is an enlarged sectional view showing a mounting configuration of
the present implement bucket leading edge;
3o Fig. 10 is an enlarged fragmented perspective view showing a preferred
cutting tooth configuration;
Fig. 11 is a view similar to the perspective view of Fig. 10 only showing
a variation of scale and configuration for the present implement; and
Fig. 12 is a view exemplifying operation of a preferred form of the
35 present invention.
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Best Modes for Carrying Out the Invention and Disclosure of Invention
Referring now in greater detail to the drawings, attention is first drawn
to Fig. 1 where a preferred implement 10 is shown mounted to an excavator 12
with earth excavating bucket 14. In the illustrated example, the excavator 12
is a tractor and the bucket 14 is of a "front loader" style. It should be
noted
that the nature of the excavator 12 may vary, as may the configuration and
usage of the bucket 14. For example, the present implement may be useful on
'backhoe" excavators, graders, shovels, and other forms of excavators and
excavator buckets.
m Further, the term "bucket" as used herein is to be understood in a
broad context to include not only the bucket form shown, but other
configurations including but not limited to scraper blades, demolition blades,
and
shovel buckets, all of which have an earth engaging edge. Still further, it is
to
be understood that the present implement 10 may be supplied as a retrofit
~5~ structure for existing buckets 14 or as an element in combination with a
bucket
assembly for distribution as original equipment.
The bucket 14 generally will include a leading edge 16 and most
preferably a substantially flat bottom surface 18 adjacent the leading edge
16.
These components and the remainder of the bucket structure may be produced
2o using conventional construction techniques and materials well known in the
excavation equipment industry.
The present implement 10 in its most preferred form includes a monolithic
blade 20 that is configured for flush engagement with the bottom surface 18 of
the excavating bucket 12, substantially as shown by Figs. 1, 9 and 12.
2s The blade 20 is most preferably formed as a casting from a high strength,
wear abrasion resistant and ductile material that may be welded and machined.
A preferred material meeting such qualifications is steel, and more
specifically a
grade of steel identified by the American Society for Testing and Materials as
ASTM A148 Grade 150/125, with a chemical composition range including .33-.37%
3o carbon, .70-.90% manganese, .55-.65 % chromium, .25-.30 molybdenum, .35-.45
%
silicon, 20-.35 % nickel, a maximum of.035 % sulphur, and a maximum of .035 %
phosphorus. Heat treatment is also preferred, with the cast material being
heated to approximately 1650-1700 degrees Fahrenheit and air-quenched.
Minimum hardness is preferred to be at BHN (Brinell Hardness Number) 300.
35 It is also possible to manufacture the present blade from a solid bar or
billet of similar steel using conventional machining processes. However, it is
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most preferable and economical that the blade be cast in the configuration as
substantially shown in Fig. 2 to minimize or eliminate costly machining
manufacturing processes.
In the preferred forms, the blade 20 defines a top surface 22 configured
for flush engagement with the bottom surface 18 of the excavating bucket,
substantially as shown by Fig. 9. The preferred blade 20 also defines a bottom
surface 24, a rear edge 26, a front edge 28, and opposite ends 30 (Figs. 2, 3
and 5).
The blade 20 also defines a plurality of primary cutting teeth 32 formed
/o integrally therewith and which project in a given direction therefrom. It
is most
preferred that the teeth 32 be formed integrally with the blade 20, such that
the
entire implement 10 may be formed of a single casting.
The primary cutting teeth 32 are spaded apart along a blade length
dimension which is identified by the letter A in Fig. 2. The teeth 32 include
/6 primary cutting edges 34 that are most preferably situated in an coaligned
orientation as shown in Fig. 3. The length dimension may vary but it is
preferably between about .61 meters to about 3.66 meters. Each of the primary
cutting edges 34 has a width dimension C (Fig. 10) which is measured along the
length dimension of the blade.
2o Secondary cutting edges 38 are also defined by the blade 20. The
secondary edges 38 are individually interspersed between the primary cutting
teeth
32 along the blade. At least some, and most preferably all of the secondary
cutting edges 38 are recessed within the blade in relation to the primary
cutting
edges 34. It is also preferable that the secondary cutting edges 38 be
2s substantially coaxially aligned as shown in Fig. 3, and parallel to the
primary
cutting edges.
As shown particularly in Fig. 8, the preferred primary cutting edge is not
a knife edge, but is best provided as a narrow upright surface. A vertical
dimension Z of approximately 6.35 millimeters has been found preferable for
both
30 primary and secondary cutting edges 34, 38. This arrangement enables
extended
use of the blade without significant wear along the edges. Scraping operations
such as exemplified in Fig. 12 may also serve to sharpen or at least maintain
the edges 34, 38 in substantially the configuration shown.
The cutting edges 34, 38 intersect with the bottom surface of the blade.
35 The points of intersection between the edges and the bottom surface 24 lie
along the plane of the bottom surface. The cutting edges 34, 38 are thus
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presented for engagement with materials as shown by Fig. 12, flush with a
working surface. This arrangement facilitates clean-up and loading of loose
material without the blade riding up and over the materials and thus leaving
material behind.
The secondary cutting edges 38 also include width dimensions, as identified
in Fig. 10 at D. A preferred relationship exists between the width C of the
primary cutting edges, and the width D of the secondary cutting edges. It is
also preferred that the sum of the primary cutting edge widths C be greater
than the one half of the length dimension A of the blade. The above
relationships appear to contribute to the operational efficiency of the
present
implement.
Gullet side walls 40 are defined by the blade and join the primary and
secondary cutting edges 34, 38. It is best that the gullet side walls 40 be
substantially perpendicular to the respective cutting edges, and that they be
~5 joined to the secondary cutting edges by fillets 45 (Fig. 4).
Fillets 45 are formed in the blade and are located between the gullet side
walls and the secondary cutting edges 34, 38. The fillets 45 are used to
strengthen the teeth and avoid breakage during use. To this end, the preferred
fillets 45 are formed with an approximate I.6 millimeter radius.
2o The second cutting edges 38 are recessed from the primary cutting edges
34 by a gullet depth dimension E (Fig.lO) that is less than about S0~ of the
blade width B (Fig. 6). Also, the gullet depth E is preferably less than about
twice the width dimension of the primary cutting edges.
Another relationship that is believed to have some effect on the operation
z5 of the present invention is the thickness dimension T of the blade
(measured
between the top and bottom surfaces 22, 24) to the width of the cutting edges.
More specifically, it is preferred that the thickness dimension T be about 20~
to about 50~ of the primary cutting edge width dimension C. Relative to the
gullet depth dimension E, the thickness T is equal to about 25% to 40~ of the
3o gullet depth E. In preferred forms, the thickness dimension will be between
about 1.27 centimeters to about 5.08 centimeters.
In the preferred forms of the invention, the blade defines primary and
secondary beveled surfaces 42, 44 respectively that form acute angles with the
bottom surface 24. The bevels 42, 44 extend angularly toward the rear edge 26
35 from the respective primary and secondary cutting edges 34, 38 and
intersect with
the top surface 22 along lines that substantially lie in a common plane with
the
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top surface. It is preferable that the angles lie within a range of about
18° to
about 27°, and further that the angles of the secondary beveled
surfaces are
approximately equal to the angles of the primary beveled surfaces.
A blade-to-bucket mounting attachment 46 may be provided to rigidly
secure the blade to the excavating bucket with the primary and secondary
cutting
edges spaced forwardly of the leading edge. This condition is shown in Fig. 9
for one bucket configuration in which the leading edge 16 is beveled, and in
another configuration in Fig. 12 wherein the bucket shown includes a flat
leading
edge. In either case, the mounting attachment is provided in such spatial
/o relation relative to the primary and secondary cutting edges that both
edges will
be situated forwardly of the associated leading bucket edge. Also in preferred
forms, the attachment may be comprised of appropriately formed mounting holes
48 formed in the blade at the preselected locations, and conventional mounting
fasteners 50. It is also possible that the blade could. be _wslded to the
bucket,
t5 or otherwise attached by known, conventional fastening techniques.
Prior to operation of the present invention, blade selection is made
according to the form and size of bucket to which the blade is to be attached.
The blade 20 may be manufactured in numerous sizes to fit various forms of
buckets and bucket sizes. In fact it is possible that the blade may be
provided
2o in several sections, which are joined endwise, to span a particularly wide
bucket.
If the present blade is to be provided in combination with a bucket, this
selection process and the mounting steps described below may take place at a
common manufacturing site. If the blade is provided as a retrofit for
attachment
to buckets, the mounting process may occur wherever the bucket is located.
25 Installation of the selected blade 20 on a selected bucket 14 is
accomplished using the mounting fasteners 50 or another attachment technique.
Care is taken to assure that the blade 20 is secured to the bucket 14 with the
top surface 22 in flush engagement with the bottom surface 18 of the bucket.
Thus the top surface 22 becomes coplanar with the bucket bottom, at least
along
3o the bucket leading edge I6. This also makes the bottom surface 24 parallel
with the bucket bottom, since the surface 24 is preferably parallel to the top
surface 22. Fig. 12 illustrates this relationship.
Care is also taken during mounting of the blade that the primary and
secondary cutting edges 34, 38 are situated forwardly of the bucket leading
edge.
33 Where the bucket has an inclined leading edge (Fig. 9) it is preferred that
the
secondary inclined surfaces 44 be positioned so they lead directly to or are
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substantially coplanar with that same surface. Fig. 12 shows the relationship
of
a blunt leading edge 16 with the blade, in which both primary and secondary
cutting edges of the blade are forward of the bucket leading edge.
Once the blade 20 is properly secured to the bucket, utilization of same
may begin. In clean-up operations or where material is to be removed from a
support surface, the bucket is positioned such that the blade bottom rests in
flush engagement with the support surface. The bucket and blade are then
moved forwardly into the material to be removed. Since the flat bottom surface
24 is consistent across the blade, the blade will not ride over the material
and
the clean-up operation may be completed with little or no materials being Left
behind the bucket. Instead, the materials will be scooped into the bucket.
This
significantly reduces or eliminates the need for further clean-up of
materials.
This represents a significant advantage over prior blade attachments with open
spaces between teeth where materials can accumulate and be left on the support
surface. In digging or demolition work, the primary cutting edges first engage
and penetrate the materials being excavated, breaking up or shattering
materials
engaged by the blade, followed by the integral secondary cutting edges which
continue the excavating work. The geometric relationships exemplified above
significantly and positively affect the excavation effort, increasing the
overall work
2o efficiency of the present blade and bucket combination over the
conventional
bucket forms in which the leading edge is straight and blunt or beveled.
Testing of the present blade configuration has indicated significantly
improved clean-up and excavation efficiency over the same buckets using
conventional straight leading edges. Overall time for producing the same
results
2s has been significantly reduced, which results in lower power requirements
and
increased fuel efficiency for the drive implement. Further, the same blade
structure can be used effectively for clean-up and for excavating operations.
This
is another distinct advantage over specialty blade attachments that are
intended
to be use specific. Additionally, those skilled in the art have expressed
surprise
3o regarding the performance improvement noted in excavating devices utilizing
the
present invention. As the present blade wears, the tendency has been found for
the primary and secondary edges to become sharper (due to a reduction of the
dimension Z along the cutting edges) and efficiency improves even further.
Eventually, of course, the blade will wear out and at such time a fresh blade
35 may be obtained to replace the worn blade, leaving the bucket relatively
wear-
free.
