Note: Descriptions are shown in the official language in which they were submitted.
Ref 60002/5
APPLICATION FOR CANADIAN LETTERS PATENT
INVENTOR: James Grant
ASSIGNEE: Peninsula Alloy Inc.
TITLE: WEAR PLATE ASSEMBLY
TO ALL WHOM IT MAY CONCERN:
BE IT KNOWN THAT I, James Grant
of 412 Sandra Boulevard, Sudbury, Ontario, P3C 3K9
Citizen of Canada, have invented a:
WEAR PLATE ASSEMBLY
of which the following is a specification
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1
WEAR PLATE ASSEMBLY
FIELD OF THE INVENTION
This invention relates to the field of wear plate assemblies for loader
buckets.
BACKGROUND OF THE INVENTION
In the mining and construction industries, loading and moving of heavy
materials
such as sand, gravel and rock is often accomplished using heavy machinery such
as scoop
trams, front-end loaders and powered bucket digging devices. During operation,
these
buckets tend to wear along their leading edges due to abrasion when entering
the material
pile and during contact with the ground. During use, the lip may tend to wear
down,
sometimes very quickly. After the lip wears down to a point where the base
plate or
bucket are threatened with wear, the bucket may typically be removed and sent
to be
refurbished by replacing the lip. Bucket removal is a relatively common
practice in the
mining industry at present. Rework and replacement of a bucket lip can be a
major
undertaking involving burning, cutting and welding. Time may be lost if the
loader is
transported to a shop where the bucket can be replaced. In a mining setting,
the loader
may remain inside the mine, the bucket being cut into two pieces and
transported out of
the mine to the surface. The replacement bucket may be returned in two pieces
and be
welded together before being placed on the loader. If a replacement bucket is
not
available or the replacement process is too cumbersome at the time, an
operator may
continue operating the loader nonetheless. As a result the base plate or the
bucket itself
may be damaged through overuse and may then require much more extensive repair
than
would otherwise be expected. The replacement of the base plate or bucket may
well be
much more costly than the use gained by operating the loader for the extra
time.
Alternatively, the mine may keep an inventory of repaired buckets available.
It is
advantageous to reduce the ratio of buckets in inventory to the number of
buckets in use,
since buckets held in inventory, or being refurbished, are capital assets that
are not
earning revenue. Thus it is advantageous to make relatively simple replacement
of wear
plates and teeth in the mine, and to reduce the number of major overhauls
requiring
bucket removal to the surface.
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When a loader or underground scoop tram is used for loading or transporting
materials it is common to weld a base plate to the lower front edge of the
bucket, the
welding join line running from side to side across the bucket. The bucket is
usually made
of mild steel and the base plate is made of a mild steel or high carbon steel.
The base
plate is sometimes of greater thickness than the bucket plate. The upper
surface of the
base plate is installed flush with the inner surface of the bucket. The base
plate has a
lead, provided by leading edges that extend forwardly at an angle from the
lower corners
of the bucket to converge at a central point or tip. Different leads are
selected by different
operators to suit specific conditions. It is common for base plates to have
leads of six,
eight, ten or twelve inches, the lead being the distance that the tip is
located forwardly of
a line joining the outside corners of the bucket. A number of known scoop tram
buckets
have widths in the range of 56 to 112 inches, the tangent of the angle of the
lead, viewed
from above, being the lead dimension divided by the half width of the bucket.
Although the base plate can be more abrasion resistant than the material of
the
bucket, it is common practice to protect the base plate from premature wear by
mounting
a replaceable sacrificial wear lip or wear edge on the leading edges of the
base plate.
Typically, these wear edges are cut to suit, and are welded or bolted in
place. Although
welding and cutting operations tend to require greater labour they have been
historically
preferred. Releasable mechanical fastener systems, by contrast, tend to be
regarded with
considerable scepticism in view or the high stresses in the lip area during
operation.
However, mechanical fastening, as opposed to welding, permits different
casting alloys to
be used for the wear segments, and may tend to reduce reliance on specific
welding skills
to produce good welds in high wear alloys, such as, for example, Manganese
steels.
It would also be advantageous to supply, and to bolt on, lip and wing wear
segments that
may be replaced several times over the life of the bucket. Some relatively
complicated
mechanical adapter systems are known, such as the Hensley (t.m.) J-bolt Edge
System.
This system uses a cleat that is welded to the bucket base plate, and a J-
shaped bolt that
attaches to the cleat to tighten a removable wear segment in place. The
tightening action
of the bolt is fore-and-aft, as opposed to vertical. The base plate does not
have vertical
bores for bolts. It would be advantageous to use a through-hole, as opposed to
welded
cleats. Leaving aside the lifting lug, the adapter fitting in the J-Bolt
design stands up into
the flow of incoming material a distance that is greater than the thickness of
the base plate
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of the bucket. It would be preferable to employ fittings with a lower profile,
that may
tend less to stand in the way of incoming material. In some replaceable wear
equipment,
the wear segments are bolted to the base plate by a dual flange fitting. This
may result in
looseness and high bolt stresses. It would be advantageous to use a single
flange
attachment.
The supply of replaceable wear edge assemblies for these wear areas, namely
the
forward lip and adjacent wing leading edges of excavating or loader buckets is
the subject
of this application, as is a system of standardisation that includes initial
installation of
base plate and wing segments, followed by the supply and installation of the
remaining
removable, and replaceable, wing and lip wear segments.
It is usual to weld a base plate along the lower edge of the bucket and to
attach a
cast, wear resistant lip along the leading edges of the base plate, as well as
wing wear
segments at the lower corners of the bucket. Usually, the base plate is welded
to the
bucket and the lip is welded to the base plate. The lip is usually made from a
materiel,
often as a casting, that is more wear resistant than the material used in the
base plate or
the bucket generally. For heavy digging the base plate and lip wear segments
usually
have a tapered or convergent lead, i.e., their front edges converge forwardly
from the
lower corners of the bucket, in some cases to a pointed tip as noted above,
having an
appearance of a pointed spade.
Loader buckets currently come in a variety of sizes. The present supplies of
lip
wear components to meet the numerous different bucket leads involves producing
and
stocking a wide variety of wear segments. As a result, many different sizes of
lips may
be manufactured and stocked to meet demand. This may result in a need to
maintain a
relatively large inventory. Another option is to sell one size of lips that
can be trimmed
by the user to match the bucket size. The rework of permanently installed
(i.e., welded)
wear components is also a major undertaking involving burning, cutting and
welding. In
many case the work must be done in a heavy-duty garage. The lost machine
operating
time, the extent of the rework and the extra stocking of components may tend
to be very
costly and inefficient.
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Replaceable, welded, leading edge wear shroud kits have been used in the past,
but, in addition to the cutting and welding requirement, have tended to
include elements
as much as 40 inches wide or more. Such a part may weigh three hundred pounds
or
more. In general, the greater the weight of the part, the more difficult it is
to handle,
whether by hand or by machine, whether in shipping, transferring from one form
of
transport to another, installation or removal.
Further, the mating faces of the parts may not be planar, and may not be
aligned
with the forward and rearward direction of the bucket. Where the mating
interfaces are
IO arcuate or splayed, it may not necessarily be possible to remove each part
without first
removing another neighbouring part. The other part may not require
replacement. This
may complicate the occasional replacement of a single broken part, and may
make
general replacement of wear segments more time consuming than it need be. It
would be
advantageous to tend to avoid this complication by making the sides of
adjoining
segments straight and parallel, and preferably running in the fore-and-aft
direction, to
permit a segment to be slid into place between its neighbours. Although larger
segments
can be used, it would be advantageous to employ segments that are not more
than 24
inches wide, and preferably not more than 20 inches wide. Similarly, it would
be
advantageous to keep the weight of each wear segment, or as many of them as
practicable, below about 250 lbs., and preferably below about 200 lbs. It
would also be
preferable to be able to remove one segment without having to remove others
first. That
is, it would be advantageous to employ wear segments that do not require a
specific order
of removal and installation.
It would be advantageous, to adopt a wear plate system involving relatively
few
components, and relatively simple installation such as may be made in place
with only
minor lifting devices and bolting tools.
The effectiveness of a loader is determined by the number of loads per hour
that
can be loaded for a given material. Currently, lips for attachment to base
plates have
wedge shaped or rectangular profiles. These profiles may not be conducive to
easy
rolling of muck or other materials into the bucket. As a result, the
effectiveness of the
loader is reduced as muck gets caught on the lip or is slow to roll off the
lip into the
bucket. It may be advantageous to have a lip profile that may tend to
encourage rolling
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motion in the muck. It may also be advantageous to have a lip profile in which
the tip lies
near or at the plane of the lower surface of the base plate.
It would be advantageous to have a lip that is mechanically attachable to, and
removable from, the base plate relatively quickly and relatively easily, that
is, without
cutting, grinding or welding. It would be advantageous not to have to trim a
cast or
forged part to size for installation. It would also be advantageous if the
shape of the lip
were designed to encourage a rolling action in the material to be loaded. It
would also be
advantageous to use a method for providing lips which reduces inventory
variety and
inventory costs while still supporting a wide variety of bucket widths.
Accordingly, there is a need for a new lip design and a new method for
providing such lips.
SUMMARY OF THE INVENTION
In one aspect of the invention, there is a set of wear segments developed to
incorporate advantages over a number of existing systems. The wear sections
are bolted
in place and are sized for relatively easy handling and bolt-on installation.
In a method
aspect of the present invention this may tend to permit replacement in place
at the
worksite location, preferably without the use of welding, heavy machinery or
the bodily
removal of a bucket.
In another aspect or feature of the invention, there is a single flange,
bolted lip-to-
base-plate connection that may tend to reduce or eliminate lip movement
relative to the
base plate during operation. This may tend to reduce bolt shear stresses as
compared to
the dual flange arrangement mentioned above. In a further aspect or feature of
the
invention, the base plate has a sloped, or chamfered section that extends
rearwardly and
downwardly from the flat abutment of the forward edge the base plate to its
base side, or
surface. This chamfer may tend to permit a thicker wear lip section in the
critical area.
In another aspect or feature of the invention, the wear segments have a wedge
shape that may tend to promote relatively even top and bottom wear and may
tend to
reduce friction when penetrating a pile of loose material. The wedge shape may
tend to
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present a reduced impediment to material flowing into, or out of, the bucket
due to a
thinner top section flange at the base plate connection. In a further feature
of that aspect
. of the invention, the lip has a top curved profile that may tend to induce
material entering
the bucket to roll upwards and away from the bucket, possibly resulting in a
relative
reduction in friction between the material and the steel of the wear segment.
In another aspect or feature of the invention, standardisation of lip wear
components to a limited number of sizes as required to meet a plurality of
bucket sizes,
may tend to reduce inventory stocking difficulties. In another feature of that
aspect of the
invention, there is a relatively small number of sizes of wear segments from
which a
selection of combinations and permutations will permit kits to be assembled to
fit a
relatively large number of bucket sizes. In an additional feature, wear
segments of
differing thicknesses are provided to suit differing thicknesses of base
plates as chosen by
operators according to bucket capacity and operating conditions. In another
feature of the
I S present invention, the bolt-on segments may tend to be relatively more
easily installed in
place without the use of heavy equipment, cutting or welding machines.
In another aspect or feature of the invention, there is a method in which
there is a
first modification of a standard bucket that involves the cutting away of
existing bucket
base plate protrusions, and the welding on of machined base plate wing
sections. (The
forward location of the base plate apex from the lower pivot pin is dictated
by the original
manufacturer's equipment specifications). According to a feature thereof,
initial
modifications are made that involve cutting and welding such as may tend to be
of a
permanent nature and such that the bucket should not tend to require further
rework of a
permanent nature for the duration of the life of the bucket.
In another aspect or feature of the invention there is a loader bucket
assembly. It
has a loader bucket having a backshell and a pair of opposed end walls mounted
thereto.
The backshell and end walls define a bucket cavity having a width. The
backshell has a
lower portion. The end walls are spaced from each other a distance defining a
width of
the loader bucket. A base plate is mounted to the lower portion of the
backshell. The
base plate has a width extending across the width of the loader bucket. The
base plate has
a leading edge, a first surface oriented inwardly relative to the backshell
and a second
surface oriented outwardly relative to the backshell. The base plate has bores
defined
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therethrough. The bores are inset from the leading edge. At least one wear
segment is
mounted to the base plate. The wear segment has a leading edge oriented
forwardly away
from the base plate. The wear segment has a trailing portion having an
accommodation
for the leading edge of the base plate. The leading edge of the base plate has
a male
profile. The accommodation of the wear segment has a female profile matching
the male
profile of the leading edge of the base plate. The female profile includes a
first portion
engaging the first surface of the base plate and a second portion engaging the
second
surface of the wear plate. The wear segment has at least one bore formed
therein. The
bore of the wear segment and a corresponding one of the bores of the base
plate are
aligned when the male and female profiles are engaged. The wear segment and
the base
plate are connected at the aligned bores by an impermanent mechanical fastener
in single
shear.
In an additional feature of that aspect of the invention, the trailing portion
of the
wear segment includes first and second spaced apart flanges and a root section
from
which the flanges extend rearwardly, the flanges and the root co-operating to
define the
accommodation. In another additional feature, when the loader bucket rests
with the base
plate adjacent a ground surface, the first flange is an upper flange and the
second flange is
a lower flange. The lower flange extends further rearwardly than the upper
flange. The
bores of the wear segment are formed in the lower flange. The upper flange has
tool
access accommodations formed therein adjacent the bores of the lower flange.
In yet
another additional feature, the bores of the lower flange has centerlines
lying in a plane,
and the upper flange has a rearward edge lying abreast of the plane of the
centerlines. In
still yet another additional feature, the bores of the lower flange are
countersunk to
accommodate a locknut.
In a further additional feature, the bores of the base plate are countersunk
to
accommodate a tapered countersunk head of a threaded fastener. In still a
further
additional feature, the male profile has a chamfer, and the female profile has
a matching
chamfer. In yet a further additional feature, the assembly includes a
plurality of the
segments having a combined width corresponding to the width of the base plate
In an additional feature, the base plate has a central point and left and
right hand
leading edges trailing rearwardly and outwardly from the point. The assembly
includes a
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plurality of the wear segments, half of the segments being left handed, and
half of the
segments being right handed. In another additional feature, when the bucket
assembly is
resting with the base plate on a ground surface, the first surface of the base
plate is an
upper surface, and the leading edge of the wear member includes a tip having
an
abutment intersecting the plane of the second surface of the base plate.
In yet another additional feature, all of the bores in the base plate are on a
uniform
setback distance from the leading edge. In still yet another additional
feature, the wear
segment includes an upper surface extending rearwardly from the tip of the
wear segment,
and the upper surface is scalloped to encourage rolling action in the work
material. In a
further additional feature, the bucket has a width in the range of 58 to 112
inches, and the
leading edge of the base plate are chosen from an inventory of segments
consisting of
segments of less than 24 inches in width.
1 S In still a further additional feature, the bucket has a width in the range
of 58 to 112
inches, and the wear segments for the base plate are chosen from an inventory
of wear
segments including wear segments of at least two widths. In yet a further
additional
feature, at least two widths are chosen from an inventory of wear segments of
up to four
widths selected from the set of widths consisting of (a) about 14 -'/2 inches;
(b) about 16
inches; (c) about 18 inches; and (d) about 20 inches. In an additional
feature, the wear
segment has at least two of the bores formed therein, and the wear segment is
connected
to the base plate by at least two of the impermanent mechanical fasteners.
In another additional feature, the impermanent mechanical fasteners are
threaded
fasteners. In yet a another additional feature, at least two bores are spaced
apart and stand
at a common setback distance relative to the leading edge of the base plate.
In still yet
another additional feature, the wear segment has a pair of side faces, the
side faces lying
in parallel vertical planes, the vertical planes being oriented in a fore-and-
aft direction
relative to the width of the bucket.
In a further additional feature, the base plate has a central lead point and
left and
right hand leading edges tapered sideways outwardly and rearwardly. A
plurality of left
handed wear segments is mounted side-by-side along the left hand leading edge.
A
plurality of right hand wear segments is mounted side-by-side along the right
hand
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leading edge. At least one of the left hand wear segments has a leading
abutment tip
running parallel to the left hand leading edge and a pair of parallel side
faces extending in
a fore-and-aft orientation relative to the width of the bucket.
In another aspect or feature of the invention, there is the combination of a
base
plate and replaceable wear segments for a loader bucket having a width. The
base plate
has a trailing portion for permanent attachment to a lower portion of the
loader bucket,
and a leading portion extending forwardly thereof, and a width corresponding
to the width
of the bucket. The leading portion has a leading edge having a male profile.
The base
plate has a first surface and a second surface, the first and second surfaces
being on
opposite sides of the plate and lying in first and second parallel planes. The
first surface
of the base plate being for orientation inwardly relative to the bucket. The
plate has a
plurality of bore holes formed therein. The bore holes extend through the
plate. The bore
holes are set back from the leading edge. The wear segments have a combined
width
L 5 corresponding to the width of the bucket. Each segment has a first flange
for engaging
the first surface of the base plate, and a second flange for engaging the
second surface of
the base plate. The first and second flanges are joined at a common root
portion of the
segment. The flanges and the root portion define between them a rearwardly
facing
socket. The socket has a female profile matingly engageable with the male
profile of the
leading edge of the base plate. Each wear segment has a pointed leading
portion for
engaging material to be carried in the loader bucket, the leading portion
extending
forwardly of the socket. The second flange has at least one bore hole formed
therein for
alignment with a corresponding one of the bore holes of the base plate. The
bore hole of
the wear segment is aligned with the corresponding bore hole of the base plate
when the
male and female profiles are engaged. The base plate and the wear segment are
securable
by a mechanical fastener mounted through the bores across a single connection
interface.
In an additional feature, the male profile of the base plate includes a
chamfered
edge, and the female profile has a mating chamfer. In another additional
feature, the base
plate has a first through thickness, and the first flange has a second through
thickness, the
second through thickness being less than the first through thickness. In yet
another
additional feature, the base plate has a first through thickness, and the
second flange has a
second through thickness, the second through thickness being greater than the
first
through thickness.
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In still yet another additional feature, the bores in the base plate are
countersunk
from the first surface to admit a fastener having a countersunk head lying in
a position
chosen from the set of positions consisting of (a) flush with; and (b) shy of,
the first
surface of the base plate. In a further additional feature, the first flange
has tool access
reliefs formed therein, the reliefs being located in positions corresponding
to the bores of
the second flange.
In still a further additional feature, the leading portion of the segment has
first and
second diverging flanks extending rearwardly of the tip thereof. The first
flank extends
from the tip toward the first flange. The second flank extend from the tip
toward the
second flange. The first flank has a surface having a convex profile relative
to the second
flank.
I 5 In yet a further additional feature, the leading portion of the segment
includes an
abutment face. The abutment face and the first flank meet along a vertex. The
vertex lies
between the first and second planes. The vertex lies closer to the second
plane than to the
first plane. In an additional feature, the leading portion includes an
abutment face. The
abutment face and the first flank meet at a first vertex. The abutment face
and the second
flank meet along a second vertex. The first vertex lies to one side of the
second plane,
and the second vertex lies to the other side of the second plane.
In another additional feature, the assembly includes wear segment attachment
fittings for mounting to the vertical edges of side walls of the bucket, and
shrouds for
mounting to the wear segment attachment fitting. The shrouds each include a
pair of
rearwardly extending parallel flanges and a rearwardly facing slot defined
therebetween.
The attachment fittings each include a forwardly facing web. The web and the
slot being
matable. The web and one of the flanges has corresponding bores formed therein
to
admit a fastener to connect each shroud to a respective side wear segment
attachment
fitting across a single connection interface.
In another aspect or feature of the invention, there is a replaceable wear
segment
for impermanent mating with a leading edge of a permanently affixed base plate
of a
loader bucket assembly. The base plate has bore holes formed therethrough
adjacent to
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the leading edge. The wear segment has a body has a leading portion and a
trailing
portion. The leading portion has a leading edge for advancing into a pile of
material to be
loaded into the loader bucket. The trailing portion has a pair of first and
second spaced
apart flanges, the flanges having proximal ends joined at a root, and distal
ends extending
rearwardly thereof. The first and second flanges have respective opposed faces
lying in
respective first and second spaced apart parallel planes. The opposed faces
and the roof
co-operate to define a rearwardly facing socket. The socket has a profile to
match the
leading edge of the base plate. The second flange has a bore hole defined
therein to admit
an impermanent mechanical fastener to be inserted therethrough, and through a
bore of
the base plate for impermanent single shear connection of the wear segment to
the base
plate.
In an additional feature, the segment is a casting. In another additional
feature,
the trailing portion of the wear segment includes first and second spaced
apart flanges and
a root section from which the flanges extend rearwardly, the flanges and the
root co
operating to define the accommodation. In yet another additional feature, when
the first
flange rests on a ground surface, the first flange is an upper flange and the
second flange
is a lower flange. The lower flange extends further rearwardly than the upper
flange. The
bores of the wear segment are formed in the lower flange. The upper flange has
tool
access accommodations formed therein adjacent the bores of the lower flange.
In still yet another additional feature, the bores of the lower flange have
centerlines lying in a plane, and the upper flange has a rearward edge lying
abreast of the
plane of the centerlines. In a further additional feature, the bores of the
lower flange are
countersunk to accommodate a locknut. In still a further additional feature,
the
accommodation has a chamfered surface at the root. In yet a further additional
feature,
the leading edge of the wear member includes a tip having an abutment
intersecting the
plane of the second surface.
In an additional feature, the wear segment includes an upper surface extending
rearwardly from the tip of the wear segment, and the upper surface is
scalloped to
encourage rolling action in the work material In another additional feature,
the wear
segment has at least two of the bores formed therein. In yet another
additional feature, at
least two bores are spaced apart and stand at a common setback distance
relative to the
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leading edge of the base plate. In still yet another additional feature, the
accommodation
has a first through thickness measured between the first and second parallel
planes, and
the first flange has a second through thickness, the second through thickness
being less
than the first through thickness.
In a further additional feature, the accommodation has a first through
thickness
measured between the first and second parallel surfaces, and the second flange
has a
second through thickness, the second through thickness being greater than the
first
through thickness. In still a further additional feature, the first flange has
tool access
reliefs formed therein, the reliefs being located in positions corresponding
to the bores of
the second flange. In yet a further additional feature, the leading portion of
the segment
has first and second diverging flanks extending rearwardly of the tip thereof.
The first
flank extends from the tip toward the first flange. The second flank extend
from the tip
toward the second flange. The first flank has a surface having a convex
profile relative to
the second flank.
In an additional feature, the leading portion of the segment includes an
abutment
face. The abutment face and the first flank meet along a vertex; the vertex
lies between
the first and second planes. The vertex lies closer to the second plane than
to the first
plane. In another additional feature, the leading portion includes an abutment
face. The
abutment face and the first flank meet at a first vertex. The abutment face
and the second
flank meet along a second vertex. The first vertex lies to one side of the
second plane,
and the second vertex lies to the other side of the plane.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention and to show more clearly
how
it may be carried into effect, reference will now be made by way of example to
the
accompanying drawings, which show an assembly according to the preferred
embodiment
of the present invention and in which:
Figure 1 is an exploded perspective view of a front end loader bucket having a
base plate having lip wear segments bolted to its leading edges;
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Figure 2 is an enlarged side corner view of a base plate of the loader bucket
of
Figure 1;
Figure 3 is a plan view of the bucket front of Figure 1 with the wear assembly
components installed;
Figure 4 is an end view of an installed wing plate and wing wear segment of
the
bucket of Figure l;
Figure 5 is a sectional view of an installed wing and wing wear segment taken
along section '5 - 5' of Figure 4;
Figure 6 is a sectional view through a front lip wear segment, the base plate
and
bucket base connecting plate taken along section '6 - 6' of Figure 3; and
Figure 7 is an isometric prospective view of a lip wear segment for the bucket
of
Figure 1.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT
The description that follows, and the embodiments described therein, are
provided
by way of examples of particular embodiments of the principles of the present
invention.
These examples are provided for the purposes of illustration, and not of
limitation, of
those principles and of the invention. In the description that follows, like
parts are
marked throughout the specification and drawings with the same respective
reference
numerals. The drawings are not necessarily to scale and in some instances
proportions
may have been exaggerated in order more clearly to depict certain features of
the
invention. In this description the terms "leading" or "forward" refer to the
direction of
advance of the equipment into a work substance, be it earth, or gravel, or
rock, or some
other substance.
By way of general overview, Figure 1 shows an exploded view of a bucket 20 of
a
front end loader (not shown) having wear components for installation thereon.
Bucket 20
has a backshell assembly 22 in the form of a generally rectangular plate
formed on a
curve of constant radius, terminating in a leading, or lower tangential plate
portion 24 that
forms the base wall of bucket 20, and another planar portion 26 that forms the
upper edge
of bucket 20. The curved backshell assembly 22 is bounded at either end by
left and right
end walls 28, 30. End walls 28 and backshell assembly 22 co-operate to define
the scoop
area of bucket 20.
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Bucket 20 has wear components for installation along the leading portions, or
leading edges, of lower tangential plate portion 24 and end walls 28, 30. The
wear
components include a base plate 32 for mounting to tangential plate 24; an
array, or set,
of lip shrouds, indicated as lip wear segments 34, for mounting to base plate
32; wing
attachments 36 for mounting to end walls 28, 30; and corner shrouds indicated
as wing
wear segments 38 for mounting to wing attachments 36. Each of these components
is
described in greater detail below.
Bucket 20, when installed on a tram scoop (not shown) or front end loader (not
shown), is raised or lowered by means of an external mechanism, such as a boom
assembly (not shown) which carries the weight of bucket 20 through pivot
assemblies
mounted at the main pivot points, indicated as 40. Bucket 20 can be rotated
about these
points through some angular range of motion. Typically, the angular
orientation of
bucket 20 relative to the booms upon which it is mounted is controlled by
means of one
or more hydraulic cylinders, exemplified by a centrally located powered
cylinder in the
nature of a hydraulic ram 42. Hydraulic ram 42 has one end connected to the
boom
assembly, and another end connected to a rearwardly oriented portion of the
bucket
exterior that is offset by a moment arm distance from pivot points 40 such
that extension
or retraction will tend to cause bucket 20 to pivot. In addition to the bucket
mechanisms,
translational forward and rearward motion of the front end loader to force the
bucket into
a pile of material when excavating or digging is provided by the front end
loader's engine
and drive train.
BASE PLATE
Base plate 32 is affixed to a front edge 44 of lower plate portion 24 of
bucket 20
by welding or other rigid mounting means. A rear edge 46 of base plate 32 runs
parallel
to the lower edge of lower plate portion 24 of bucket 20 and is pre-machined
with a
chamfer 48 as shown on Figure 6. Chamfer 48 extends along the full length of
base plate
32 and is used for the continuous bevel welded connection between bucket 20
and base
plate 32. The weld runs along the front edge 44 of lower plate portion 24 and
the rear
edge of base plate 32 such that the upper surface of base plate 32 and the
upper surface of
the inside of bucket 20 lie flush with one another as shown in Figure 6. Base
plate 32 has
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a chevron shaped leading edge having two portions, indicated as left and right
hand
leading edges 50, 52 that extend forwardly and converge at a point, or tip,
54. That is, the
leading edges 50, 52 of base plate 32 are each tapered rearwardly from the
central point
along a horizontal rake angle, indicated as a, being the lead angle of the
bucket assembly
generally. In one embodiment a is about 12 degrees.
As shown in the sectional view of Figure 2, leading edges 50, 52 are machined
to
have a flat, vertical planar surface portion indicated as 56 adjoining the
horizontally
planar upper surface 58, and a chamfered planar surface portion indicated as
60 running
from a vertex at portion 56 to meet lower horizontally planar surface 62 on a
chamfer
angle indicated as [3. In one embodiment [i is about 20 degrees measured from
the
horizontal. The vertical portion 56 is a machined vertical face sometimes
referred to as
the abutment, or abutment edge.
1 S Base plate 32 also has an array of tooth engagement interface fittings in
the nature
of through-bores, or apertures, identified as bolt holes 64. Bolt holes 64
have a uniform
center set back distance relative to leading edges 50, 52, the setback
distance being
identified as 8. In one embodiment this distance is about 4.17 inches. The
thickness t of
base plate 32 may vary depending on the size of bucket 20 or type of
application.
Thickness t may be 1-1/2", or 1 11/16", or 2", or some other thickness as may
be found
suitable.
Base plate 32 is of a size to mate with a particular model of bucket 20. That
is,
base plate 32 has a width, indicated as 'W' that permits it to be mounted to
bucket 20.
There may be several types of front end loader bucket for which a leading
plate of width
'W' can be used. 'W' is typically in the range of 55 to 112 inches. A person
seeking to
order replaceable lip members, as described below, for a given type of loader
bucket may
tend to examine, for example, a catalogue of available plates 32, locate the
type, or width,
of bucket in question, and find the size of plate 32 suitable for that bucket.
The catalogue
may then indicate the number of lip members of stock sizes that are to be used
with that
plate, so that purchasers may select and buy them as a kit.
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WEAR SEGMENTS
The array of wear segments indicated in Figure 1 as 34 includes left and right
hand wear segments 66, 68. Inasmuch as wear segments 66 and 68 are left and
right hand
mirror images of each other, a description of the one will serve also to
describe the other.
When seen in plan view, left and right hand lip wear segments 66, 68 are
parallelogram
shaped, having a leading edge, or front abutment; a trailing edge, or rear
abutment; and a
pair of parallel side faces, 70, 72. The leading and trailing edges are
generally parallel,
and are skewed with respect to side faces 70, 72 at the same angle as the
horizontal rake
angle a (i.e., the lead angle) of leading edges 50, 52. As installed, in use
the front and
rear abutments run parallel to the base plate lead, and the sides run parallel
to the bucket
sides. Wear segments 66, 68 are bolted in place using high strength
countersunk bolts 74,
as noted below.
The body of each of wear segments 66, 68 has a leading portion, indicated
generally as 76, and a trailing portion indicated generally as 78. Leading
portion 76 is
formed into a front abutment, or leading edge indicated as tip 80 such as may
be
advanced into a work material. Trailing portion 76 has a mounting fitting, or
mounting
interface, acting as a slot or socket by which it can be relatively rigidly,
and removably,
attached to the leading portion of plate 32. Lip wear segments 66, 68 may be
made in
various widths of cast, or forged steel, or hard wearing alloy steel as
discussed below.
When seen in section as in Figure 6, trailing portion 78 has a bifurcated pair
of
first and second legs 82 and 84 formed on either side of a fitting or
accommodation for
the base plate leading edge in the nature of a recess, or rabbet, or crotch,
or slot, or socket,
however it may be termed, indicated as a wear plate leading edge engagement
slot, or
groove 86. Legs 82 and 84 may also be referred to as spaced apart first and
second, or
upper and lower flanges of segment 66, 68. Groove 86 is formed to engage the
tongue,
that is to say the leading edge 50 (or 52, as the case may be), of base plate
32.
Legs 82 and 84 are unequal in length and in thickness. That is, upper leg 82
has
an upper surface 88 lying in a first horizontal plane, Hl defining the upper
extent of the
wear segment 66 or 68; and a parallel horizontally planar inwardly facing
lower surface
90 that, when installed lies adjacent to and faces the leading margin of upper
surface 58
of base plate 32. The thickness of upper leg 82 is indicated as Tl. Similarly,
lower leg 84
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has an horizontally planar lower surface 92 lying in a second horizontal plane
H2,
downwardly offset from plane Hl by a distance T2. T2 defines the overall
through
thickness of wear segment 66 (or 68, as may be). Lower leg 84 also has an
inwardly
facing, upwardly oriented horizontally parallel planar upper surface 94. The
thickness of
lower leg 84 is indicated as T3, and the thickness of groove 86 is indicated
as T4, being
the overall thickness T2 less the thicknesses Tl and T3 of the two legs. T4
corresponds to
the thickness t of base plate 32, plus a tolerance to permit the two parts,
namely the
leading edge of base plate 32 and groove 86 of wear segment 66 (or 68) to be
engaged in
a mating manner by advancing, that is, sliding, the male part, namely the
leading edge of
base plate 32 into the female part, namely groove 86. In one embodiment Tl is
about
0.91 inches; T2 is about 4.45 inches; T3 is about 2.00 inches; T4 is about
1.54 inches.
The root, or groin region 85, of the body of segment 66, is located adjacent
the
innermost portion of groove 86, and joins the proximal ends of legs 82 and 84.
The
rearwardly facing abutment at the root is defined by a first vertically
planar, end wall
portion 96, adjoining, and extending perpendicular to, the innermost margin of
inwardly
facing lower surface 90 of upper leg 82, and a second, sloped planar surface
portion 98
extending between first end wall portion 96 and the innermost margin of
inwardly facing
upper surface 94 of lower leg 84, sloped portion 98 lying on an angle
corresponding to
angle ~i of chamfered portion 60 of base plate 32. The conforming profiles of
groove 86
and the chamfered leading edge of base plate 32 are intended to mate to a
relatively high
level of precision.
Upper leg 82 has rearwardly opening tool access recesses, or reliefs in the
nature
of scallop shaped bolt allowances 100, 102. In the embodiment illustrated,
each wear
plate has two such allowances spaced apart, although a different number could
be used.
Lower leg 84 has correspondingly placed fittings in the nature of countersunk
bores,
namely bolt holes 104 by which releasable mechanical fasteners such as
threaded
fasteners in the nature of bolts 74 can fasten wear plate 66, or 68, to base
plate 32 when
bores 64 are aligned with bores such as bolt holes 104. This condition occurs
when the
leading edge of base plate 32 is mated snug within groove 86. Although a
single bolt can
be employed, it is advantageous that two or more bolts be used, since this
will tend to
discourage the wear segment from working due to any urge to pivot about a
single bolt
fitting, such as might, repetitively, cause the bolts to loosen or fail more
easily over time.
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The square shouldered countersink 108 is formed on the underside of lower leg
84
to give a recess for the nut in a position that may be less exposed to wear
than otherwise.
The recess so formed is of sufficient diameter to admit a manual or powered
socket
wrench for engaging nut 110. Bolt allowances 100, 102 similarly provide space
for a
S manual or power driven tool head to engage the countersunk head of bolt 74
during
installation and removal as it seats in the mating counter sink of bolt hole
64. The trailing
edge of upper leg 82 terminates roughly flush with, or somewhat rearwardly of,
the
vertical plane of the centreline of the bolt holes 104. When installed, bolt
74 is in single
shear relative to loads in the horizontal direction, and, being tightened to a
set torque, the
interface area of the mating parts adjacent the bolted connection is in
compression. The
tight fitting single planer interface connection may have less tendency to
develop 'play'
than a double shear connection that, for example, may tend to squeeze a pair
of opposed
flanges together. The horizontal loads are intended to be transferred across
the end wall
abutment interface, rather than through shear in the bolts.
IS
Upper leg 82 is relatively thin, being of lesser thickness than either base
plate 32
(or groove 86), to encourage easier loading and unloading of bucket 20
generally. Lower
leg 84 is relatively thick, being thicker than not only upper leg 82, but also
groove 86, and
base plate 32, to provide a measure of wear when the leading portion of bucket
20 is
advanced in a sliding orientation along the ground or other surface, and into
a pile of
material to be moved.
Leading portion 76 has an upper flank in the nature of an surface 114 and a
lower
flank in the nature of a lower surface 116, the upper and lower surfaces 114
and 116
converging forwardly toward narrow tip 80. (Alternatively said, the upper and
lower
flanks diverge rearwardly from tip 80 to the upper and lower flanges, namely
legs 82 and
84 respectively). Upper surface 114 is formed on an arc that runs from a
vertex at the
intersection of surface 114 with the plane of upper surface 88 to another
vertex at the
intersection of surface 114 with the thin vertical face of tip 80. The arc is
concave
upward. That is, the center of curvature of the arc, or portions thereof,
stands above
leading portion 70. In one example, the center of curvature lies in the
vertical plane of tip
80. The radius of curvature of the arc of surface 114 is advantageously in the
range of 15"
to 30", and is preferably about 20" to 21". In a preferred embodiment it is
20.47". This
arcuate profile of surface 114 may tend to encourage material encountered as
bucket 20 is
driven forward to have a rolling motion as it accumulates. This rolling motion
is
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considered desirable as it is thought to reduce the effort of loading bucket
20. The shape
of the leading portion may also tend to promote self sharpening in operation.
Lower surface 116 has a relatively short proximal planar surface portion 120
S adjoining, and extending forwardly of lower surface 92 of lower leg 84.
Lower surface
116 also has a relatively longer distal planar surface portion 122 extending
forwardly
from a juncture at the forward margin of portion 120 to meet tip 80 at a
vertex along the
lower edge of tip 80. Distal portion 122 is set at a shallower relief angle
relative to the
horizontal than proximal portion 120. The angled portion of segment 66 lying
between
proximal portion 120 and surface 98 is thicker than T3, and increases linearly
in thickness
in the forward direction, being thinnest adjacent the rearward margin of
proximal portion
120. The juncture of portions 120 and 122 lies abreast of the end of groove
86. That is,
the juncture lies, roughly, level with the vertical plane of end wall portion
96, or
somewhat forward thereof toward tip 80. Lower surface 92 of lower leg 84
extends to
1 S either side of bolt hole in the width direction of bucket 20 only part of
the width of
segment 66, 68 (indicated in phantom in Figure 3) in the region of the bolt
and nut to
provide local protection for them. The region of the underside of segment 66,
68 away
from the bolt hole is carried through on a flat surface parallel to the plane
of surface 92,
extending rearwardly from the line of intersection of distal portion 122 and
proximal
portion 120.
Restating this, the recess, namely groove 86, between the lower flange (lower
leg
84) and the upper flange (upper leg 82) at the rear of lip wear segment 66 (or
68) is
defined by a narrow flat front abutment, namely end wall portion 96; a
horizontal plane in
the nature of lower surface 90 on the underside of the upper flange, (that is,
upper leg 82);
a uniformly tapering plane, namely surface 98, that extends rearwardly and
downwardly
from the lower edge of the abutment; and a horizontal plane, namely plane 94
on the
upper portion of the lower flange (that is, lower leg 84). The horizontal
distance between
the abutment and the centerline of bolt hole 104 is at least b so that the
recess, (groove
86) will fit about leading edges 50, 52 of base plate 32 and allow boltholes
64 and 104 to
be aligned. The recess will then fit about the machined leading edges 50, 52
of base plate
32 as the sloping surface of chamfered portion 60 and the front vertical end
face portion
56 meet the plane of planar surface 98 and the rear abutment, namely vertical
end wall
portion 96, respectively, when the lip wear segments 66, 68 are affixed to
base plate 32.
Preferably, any gaps between base plate 32 and the recess are minimized.
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Left and right hand lip wear segments 66 and 68 may be arranged onto base
plate
32 such that they present contiguous leading left and right hand edges 130 and
132,
meeting at a point or tip 134 and such that bolt holes 64 are aligned with
boltholes 104.
Bolts 74 may then be passed through bolt holes 64 of base plate 32 and bolt
holes 94 of
lip wear segment 34 and closed with locknuts 110 to create a tight connection
between
base plate 32 and lip wear segment 34.
Each of wear segments 66, 68 has defined in it as a means of indicating the
extent
of wear and replacement time prior to damaging base plate 32. Wear-indicating
hole 136
passes through the entire thickness of lip wear segment 66, 68 from upper
surface 114 to
lower surface 116. When lip wear segment 66, 68 has not been used, hole 136
can only
be seen from above and below lip wear segment 34. If, after use and upon
inspection of
lip wear segments 34 it is apparent that some of the length of wear-indicating
hole 120
can be seen from the front, lip wear segments 34 can be replaced to prevent
damage to
base plate 32.
As shown in Figures 1 and 5, wing segments 38 are generally trapezoidal
plates.
Wing segments 38 have an inclined upper, or leading edge 142 and a parallel ,
though
shorter, inclined lower or trailing edge 144 parallel to leading edge 142. The
horizontal
side of the trapezoid is indicated as a base or lower edge 146. The vertical
side of the
trapezoid is indicated as a rearward edge 148. Leading edge 142 and trailing
edge 144
are angled away from the vertical at an angle 8.
Inasmuch as base plate 32 serves as intermediary adapter fittings for mounting
segments 66 and 68 to bucket 20 more generally, so also wing attachments 36
serve as
intermediaries, or adapter fittings for mounting of wing wear segments 38 to
the vertically
extending lower portions of the leading edges, or margins 152, 154, of end
walls 28 and
of bucket 20 more generally. To that end wing wear segments 38 are cut plates
that
each have a vertical side 156 welded to margin 152 or 154 of end walls 28 and
30, and a
30 horizontal side 158 welded to the side margins, or edges 160, 162 of base
plate 32. Each
plate has a generally triangular portion having an hypotenuse that is inclined
rearwardly
and upwardly at an angle corresponding to the angle of inclination of the wing
wear
segments, 38, namely angle 0. Each of wing attachments 36 also has a thinned
web
portion 164 running inwardly from the inclines edge of the hypotenuse to give
a
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trapezoidally shaped land on either side, leaving a tongue in the form of a
thinned leading
edge 166.
Wear segment 36 has a leading edge 166 having a narrow front abutment in the
nature of a tip 168 along most of its length and hollowed or scalloped arcuate
surfaces
170, 172 extending rearwardly from either side thereof. The trailing portion
174 of wing
segment 38 has two parallel flanges, identified as first and second, inboard
and outboard
legs 180 and 182 with a slot or recess, identified as socket 184 defined,
therebetween.
Socket 184 is similar in nature to groove 68. Recess 184 is shaped to fit
snugly about the
thinned section, namely web portion 166 of wing attachment 38. Flange, or
inboard leg
180 has a tapered countersink 188 to accommodate the countersunk head of a
bolt 190 to
be engaged therein. Flange, or outboard leg 182 has a clearance bore 192. Bore
192 is
not recessed like countersunk 96, but passes completely though outboard leg
182. As
installed, wing segment 38 is aligned over plate 36 such that bolt 150 may be
passed
through the step, that is, through thinned leading edge 166 in the inner
flange, leg 180,
and bolt hole 190 in plate 36. A locknut 194 is threaded onto bolt 190 and
tightened to lie
in bore 192 abutting the outside face of the thinned section 166 of plate 36.
All of
locknut 194 lies shy of the outside face of the outer flange, tending to
obtain some
protection from wear thereby. Thus flange 180 and plate 36 may be brought
together in a
tight connection similar to that of segments 66, 68 with base plate 32.
SIZES AND KITS
As there are a variety of sizes of buckets, different sizes of lip wear
segments are
required. There are over two dozen standard widths of loader buckets in use in
industry
today. It has been determined that four different standard widths of lip wear
segments 66,
68 (20 inch, 18 inch, 16 inch and 14.5 inch) can be variously combined to
yield rear plate
sets or kits suitable for use with at least 25 different standard size loader
buckets. The use
of a few standard lip wear segment sizes will reduce manufacturing costs,
shipping costs
and inventory costs as well as serve a wide variety of bucket sizes. Other
size
combinations are also possible.
In use, base plate 32 is welded onto bucket 20 along base plate rear edge 46.
Base
plate 32 is selected to have a width equal to that of bucket 20. For the given
width of
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base plate 32, a combination of standard lip wear segments 34 of left and
right hand
orientations is obtained. The total width of lip wear segments 34 is equal to
the total
width of base plate 32. Similarly, wing attachment adapter fittings, 36 are
welded in
place.
Either before or after base plate 32 is welded onto bucket 20, base plate 32
is
drilled with boltholes 64 to align with boltholes 94 of lip wear segments 34.
As well,
leading edges 50, 52 of base plate 32 may be machined to form a wedge type
abutment as
described to fit snugly within recess 100 of lip wear segment 66, 68.
After base plate 32 is mounted to bucket 20, wing attachments 36 are welded to
bucket 20 and base plate 32 along edges 130 and 132. Segment 38 is then bolted
to wing
attachment fitting, 36. After wing segments 38 are attached, lip wear segments
66, 68 are
bolted onto base plate 32.
In operation, the loader forces bucket 20 into a material pile such as earth
or ore
and lifts bucket 20 upwards. The material rolls along lip wear segment 34 and
base plate
32 into bucket 20. The curvature in lip wear segment 34 may tend to allow the
material
to roll into bucket 20 at an increased rate allowing for more loads per hour.
As well,
some material that contacts wing wear segment 38 will enter bucket 20. Again,
the
curvature of wing wear segment 38 allows for more efficient rolling motion of
the
material.
Wear plate segments 66, 68 and 38 are subject to wear during use. After some
time an operator or maintenance technician, may observe that the witness
marks, namely
wear indicating holes 136, may have worn to such an extent that insufficient
material is
left for further use.
It can be seen from the geometry of Figure 6 that the upper edge of tip 80 -
that is,
the vertex formed at the intersection of the arcuate surface 114 and the
vertical end
surface of tip 80, lies above the plane of the lower surface of base plate 32,
but below
both the planes of the mid-plate thickness and upper surface of plate 32. The
lower
margin of tip 80 lies in a plane below the plane of the lower surface of base
plate 32. As
such, it is thought that the resulting action of the work material across
segments 66, 68
may tend to wear away segments 66, 68 less severely than if the tip had been
place in a
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higher plane, such as at or above the plane of the upper surface of plate 36.
Further, it is
thought that placement of the tip in this lower plane may tend to encourage
self
sharpening of the leading edges of wear plates 66, 68.
When the wear of lip wear segment 34 is such that the rear portion of wear
indicating hole 136 is visible from the front of the loader, the lip wear
segments need to
be replaced to ensure that additional use does not result in damage to the
forward portion
of base plate 32. Lip wear segments are removed by removing the bolts
connecting base
plate 32 to lip wear segments 66, 68 and are replaced with new lip wear
segments. As
well, in a similar fashion, wing wear segments 38 can be replaced at this
time.
METHOD OF USE
An aspect of this invention is directed to a method of providing sets of lip
wear
1 S segments to consumers. This method includes three main steps. In the first
step, a
retailer or distributor obtains numerous lip wear members having widths of 20
inches, 18
inches, 16 inches and 14.5 inches (although a variety of other sizes may be
used.) The
retailer then determines for a given base plate width, which combination of
lip wear
members would give a total lip wear member width equal to the given base plate
width.
This determination may be done by simple calculation or by consulting prepared
charts or
other materials. The retailer then supplies the lip wear segments in the
selected
combination to consumers in kit form, ready for installation. The dealer may,
optionally
accept the worn teeth for return.
In the preferred embodiment, although different widths of wear segments 66, 68
are available, each has two lower flange bore holes, and the spacing of those
bore holes is
the same for all sizes, the differences in width being accounted for by a
change in the
width of the portion of the wear segment lying laterally outboard of each of
the bore
holes. This may tend to facilitate manufacture.
Another aspect of this invention is directed to a method of providing base
plates
for use with boltable lip wear segments. The base plates may be provided
separately or in
a kit with the boltable lip wear segments. The base plates may preferably be
pre-cut to
match the width of standard bucket sizes. The base plates may also preferably
have bolt
holes 64 predrilled to match the bolt holes of the boltable lip wear segments.
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A number of changes may be made to the above invention. For example, a single
large lip wear segment could be used instead of a combination of smaller lip
wear
segments. In addition, different profile configurations of the leading edge
tip of the lip
wear segment may be used for different applications. As well, the recess in
the lip wear
S segment and the corresponding leading edge of the base plate may have
different
configurations to reduce stress concentrations. In addition, other edge
profiles may be
used for the wing wear segments. Further, the base plate may be formed
integrally with
the loader bucket.
Although the wear plate segments are attached to the base plate and side plate
adapter fittings using releasably threaded mechanical fasteners in the nature
of bolts,
those bolts are to be taken as being representative of other types of
fasteners such as huck
bolts, hot forged rivets, cold formed rivets and so on. Releasably threaded
bolts are
preferred since, unlike rivets, they can be removed relatively easily without
destroying the
fastener.
In summary, form the foregoing description it can be seen that each wear lip
segment 66, 68, has a straight leading edge abutment, namely tip 80, from
which it
increases in thickness in the rearward direction. The, increases in depth of
the leading
portion of the wear segment (measured by divergence of the lower plane, or
surface 116
relative to the horizontal plane of base plate 32) in a uniform, or linear
manner, while the
upper surface follows the profile of an arc R2. At the rear, the wear lip
segment has a
lower flange, leg 84 and an upper flange, leg 82. The upper flange is shorter
than the
lower flange, and thus may tend to provide a lesser obstruction to the flow of
materials in
and out of bucket 20 generally. The upper flange, leg 82 is shorter and
thinner than the
lower flange, lower leg 84, and thus may tend to provide a lesser obstruction
to the flow
of materials into and out of the bucket. The upper flange includes semi-
circular recesses,
namely allowances 100, 102 that are concentric with each bolt hole location in
the
corresponding position in the lower flange, thus tending to provide bolt hole
access from
above. The recesses, namely allowances 100, 102 are smoothly radiused into the
trailing
edge of the adjacent portions of the upper flange. The lower flange is thicker
than the
upper flange, and includes two spaced apart recessed, clearance holes to clear
and protect
the attaching bolt locknuts.
This single interface bolted connection between the lip bottom flange and the
base
plate may tend to provide for a relatively tightly held, relatively rigid
connection, thereby
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may tend to reduce fatigue and may tend to reduce shear stresses in the bolts
more
generally. The resultant connection may tend to be a less time consuming
procedure, and
may tend to be less costly, than a welded connection.
The shaped recess between the upper and lower flanges at the rear portion of
lip
wear segment 66 or 68, namely groove 86, is defined by the lower surface of
upper leg 82
and the upper surface of the lower leg 84, the narrow front abutment, (item
96), and the
tapered, or oblique, plane 98 that extends rearwardly from the lower edge of
abutment,
(item 96). This recess is precision machined to match very closely, and
preferably
precisely, the machined left and right hand leading edges 50, 52 of base plate
32.
As noted above, a wear indicating hole 136 is provided in each of segments 66,
68
as a means of indicating the extent of wear, and may indicate that a
replacement time is
due prior to damaging or wearing into base plate 32. Base plate 32 can be of
variable
1 S thickness depending on the size of bucket 20 or type of application. The
rear base line of
base plate 32, which runs parallel to the bucket rear edge, 46, is pre-
machined with a weld
preparation chamfer 48 as shown in Figure 6. This chamfer extends along the
full length
of the plate and is used for the continuous welding connection between bucket
20 and
base plate 32.
As has been described above, the base plate front, or leading edges 50, 52 are
machined to suit the desired lead angle a and to match the lip wear recesses,
grooves 86,
drilled to conform to the selected lip wear segments, bolts, diameter and
locations. The
base plate forward edges 50, 52 are machined to form the wedge shape. The edge
is
tapered down and back from the narrow abutment and all sharp corners along the
abutment are machined smooth. The two triangular wing attachments 36 may be
cast or
fabricated from abrasion resistant materials. The triangular opposed adjacent
corner wear
attachments 36 include recesses on the outer edges to facilitate welding to
the inside and
outside lines of the bucket vertical front corner and the topsides of the base
plate 32. The
center sections of the wing segments 38 are drilled with two holes to match
the wing wear
segment 38 bolt size (item 150) and locations. The center web (item 166) of
the wing
segment attachment 36 is made to fit inside the rearward recess of the wing
segment 38.
The cast wear wing segments 38 have a narrow front abutment that slopes
outwardly
towards the rear and includes a recess (socket 184) that fits over the wing
segment center
rib, namely item 166. Two holes are drilled through the rear flanges of the
wing wear
segments to match the bolt hole locations on the wing segment. The inner hole
is
20858903.5
CA 02358339 2001-10-05
26
countersunk to match the countersunk bolt head and the outer hole is recessed
to
completely clear and enclose the bolt locknut as shown in Figure 5. High
strength
countersunk bolts and lock nuts are used throughout the assembly.
An embodiment of the invention has now been described in detail. Since changes
in and or additions to the above-described best mode may be made without
departing
from the nature, spirit or scope of the invention, the invention is not to be
limited to those
details.
20858903.5
CA 02358339 2001-10-05
