Note: Descriptions are shown in the official language in which they were submitted.
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1 BACKGROUND OF THE INVENTION
The present invention relates to high-lift
arrangements for a blade of a motor grader. In particular, the
invention relates to an improved method of supporting the blade
beneath the frame of a grader.
In the past a number of arrangernents have been
proposed for supporting the blade of a motor grader and in
general these can be broken into two groups. The first group
uses a beam extending either side of the frame of the motor
grader and pivotable about the frame, and the second group uses
separate arms~ one to either side of the frame, and in many
cases these arms are movable to various positions. There has
also been a number of arrangements where either the beam or the
arms are fixed in position on the grader frame. The fixed
position arrangements are generally limited with respect to the
extent and position, either side of the grader, that the blade
can be positioned. In general, the most demanding
specification requires that the grader blade be capable of
moving to either side of the mainframe of the grader from a
perpendicular position at one side~to a perpendicular position
at the other. The fixed arm or fixed beam arrangement have
limited adjustability, however in many applicatLons the extreme
positions of the blade~will~not be used. The blade support
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1 arrangement should be adjustable to effect 2 to 1 and 1 to 1
banking either side of the grader as well as a di-tching
orientation either side of the grader.
In addition to the very demanding specifications set
forth above which have generally been met with either the
pivoted beam or the movable arms, the support arrangement for
the motor grader blade should be convenient to use and adjust
between the various positions. The system should be such that
there is not any substantial fouling problems with respect to
the movement of the cylinders to achieve the variaus positions,
as fouling problems can lead to extensive damage af the
hydraulic components and other structural components.
Furthermore, the support arrangement for the blade of the motor
grader must take into account the visibility of the operator
from the cab and certain specific points of the blade which are
considered somewhat critical. For bank grading, it is
generally noted that the heel of~the blade should be positioned
outside of the wheels so that the wheels do not contact the
graded surface and, ther~efore, the heel of the blade should be
visible for this particular operation. Furthe~rmore, the toe of
the blade should be visible as this is the other ~xtreme
position that IS being graded.
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1 The ideal blade positions include the 90 high-lift
to either side of the grader, a position of the blade which is
approximately 63 to effect a 2 to 1 banking operation, and a
further banking position of the blade at about 45. The
45 position and the 63 position are generally considered
the most frequent positions of the grader blade and the
positions which a system must satisfy. Therefore, the
flexibility of the system and the ease of adjusting the same
should be evaluated with respect to these normal positions,
although some merit must be accorded the 90 position as well
as the horizontal beam position.
Our earlier patent, United States Patent 4,340,119
uses a beam centrally pivoted atop the grader frame with a
locking arrangement generally provided beneath the frame. This
arrangement generally satlsfies the standards~set ~orth above,
however the loc~ing arrangement beneath the ~rame, which is a
mechanlcal arrangement, reduces the clearance beneath the frame
and requires a fair degree of accuracy with respect to~the
locking posltion of the beam when the beam position is~
adjusted. The advantages of this~mechanical lo~ck are the steel
to stee~l locking contact wh~ich is the generally accepted
standard in the~indus~try.
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The structure previously referred to above, having
movable arms either side of the grader frame, again uses a
pin-type lock arrangement for fixing the arms at various
positions relative to the frame and often these pins are either
mechanically movable to allow adjustment of the arms or beam or
are hydraulically actuated to effect adjustment of the
components. However, the fixing of these components in a
predetermined position on the frame is achieved by a mechanical
type lock. The problem of accurate positioning for locking is
compounded in the movable arm system in that two arms must be
locked rather than a single beam and freezing of locks occurs
rendering them difficult to release.
SUMMARY ûF THE INVENTION
The present invention provides a structure for
supporting the bla~de of a~motor grader b~enea~th the frame of the
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grader. This;arrangement lS of reduced complexlty an~ proviaes
advantages wlth respect~to cost of manufacture as well;as
service in the field. The~arrangement maintains the area
beneath~the~fram~e of th~e grader relatively clear and~uses a ~
link-type member disposed bètween the side~of the grader ~rame
and~a position on~the beam spaced from the central pivot
; ;locatlDn~of~the plv~oted~beam ~to effect locklng. In a preferre~
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1 embodiment of the invention, the link is an hydraulic cylinder
thus allowing an infinite number of positions of the beam
relative to the grader frame. The hydraulic cylinder also acts
as an hydraulic lock, thus overcoming the precision problems
associated with a mechanical lock.
~RIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in
the drawings wherein;
Figure 1 is a partial perspective view of a high-lift
arrangement for the blade of a motor grader;
Figure la is a perspective view of manual lock link;
Figures 2 and 3 are rear
elevational views of the high-lift;
~Figure 4 lS a slmilar rear elevational v1ew with the
high-lift rotated to one side of the motor grader;
Fi~gure 5 lS a -ront~elevational of a~modified
structure; ~
Figure 6 is a rear view of the high-lift;~ and
Figure 7 is a rear view of a modified version of the
beam ànd the connect~ion polnts of components to the frame.
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1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The mainframe 2 of the motor grader supports adjacent
the cab a generally horizontally extending support beam 4,
which universally supports at 19 hydraulic lift cylinders 6 at
either end of the support beam. The cylinders 6 are connected
to a ring gear 8 via beam 7 which provides the main support of
the road grader blade 9. Beam 7 is pulled by the grader by
means of drawbar 3. The arrangement for supporting of the
blade 9 beneath the ring gear and the ring gear are known from
our earlier patent U.S. 4,340,119 and the prior art in
general. The invention of the present application is generally
directed to the high-lift arrangement 5 for the blade 9. The
support beam 4 is pivotally supported on the shaft 10 which
extends in the fore and aft direction of the main~rame of the
road grader. The shaft 10 is secured to the mainframe 4 by two
pivoted saddle arrangements 26 to either side of the beam 4.
The beam itself intermediate the saddles 26 includes a
downwardly extending portlon which includes bearings for
cooperation with the shaft 10 to thereby pivotally secure the
beam 4 atop the mainframe 2 of the motor grader. The beam 4
rotates ~rom the generally horizontal position of Fiyure 1
through an angle of about~ 70, 35 either side~ of the
horizontal positlon. The llft cylinders 6 are universally
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1 supported adjacent the extrerr~ities of the beam 4 at a position
generally below shaft 10 (when the beam is horizontal). In
this way, the points of securement are such that with a
counterclockwise rotation of the beam 4 shown in Figure 2, the
point of securement 19 of the lefthand cylinder is below the
horizontal line passing through shaft 10 and as such, will move
through a further distance toward the frame 4 of the grader for
a predetermined amount of rotation. This is desired as
problems occur in achieving the 90 location and these
problems are reduced by positioning the cylinders such that the
far cylinder in a 90 blade position is moved as far as
possible beneath the frame of the grader, while the other
cylinder is rotated upwardly through the horizontal passing
through shaft 10 and as such~ its position is still quite
spaced from the mainframe. Therefore, by positioning the
support positions of hydraulic cyIinders 6 below the horizontal
line passing through shaft 10, advantages are achieved with
respect to both cylinder~s when considered with respect to the
requirement to position the blade at 90 to either side of
the motor grader. The preferred separation of the cylinders is
fifty inchès.
Integral with beam 4 and to one side of the mainframe
4-is a downwardly and rearwardly extending arm 14 having an end
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1 15 which is rearwardly offset relative to the center line of
the beam 4 about eight inches. An hydraulic shift cylinder 16
is secured to the end 15 and shifts the ring gear 8 in a
generally traverse movement relative to the mainframe 4. In
this way, the position of the blade, either beneath the grader
or to the side thereof, is accomplished. As can be seen from
the figures, arm 14 is spaced from the mainframe of the grader
when the beam is in the generally neutral position and is
positioned to allow, without interference, the desired rotation
of the beam about shaft 10. To the other side of the frame 4
as shown in Figure 1 and Figure la, is a lock link 20 which is
pivotally secured to the beam at position 22. The other end
portion of the lock link is pinned or secured to the side of
the frame 4 of the grader by pin or securing means 24. The
link 20 includes a number of circular holes 23 in the length
thereaf which are positioned to achieve the desired fixed
positions of the beam relatlve to the grader. In this case,
the link provides a manual type lock arrangement where it would
be necessary:for the operator to remove the pin 24 and cause
rotation of the beam 4 to the~desired position and effect
locking by replacing the pin 2~i in an appropriate aligned
aperture in flange 25. This lock link arrangement pinned to
the slde of the mainframe of the grader maintains the space
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1 beneath the road grader substantially clear and allows the ringgear 8 to essentially come immediately below the grader frame
(with five inches clearance) to effect a fairly high ground
clearance of the blade directly beneath the frame as
schematically shown in Figure 4. Furthermore, this simple lock
arrangement greatly reduces the cost and it can be recognized
that advantages are achieved in that if wear does occur, either
pin 24 or the various connections of the link 20 to the beam 4
or the beam to the frame can be accomplished quite easily. The
lo bearings type connection associated with each of these components
are common an~d are~readily available and easily replaced by the
people in the field. Such is not the case in prior art
structures where, in some cases, a very large bearing is placed
completely about the frame of~the grader wlth~a beam rotating
about the~center axls of the frame. The point of securement of
the`link 20 to the beam 4 is spaced from the shaft lû to re~uce
the stress concentration on the beam 4 at securement point 22.
However, the beam can withstand substantial stress and the
position~of~lock arrangement, generally close to the ma~inframe
of the grader, improves~vlsiblllty o;f the blabe beneath the
grader frame. For~example,~the link 20 could be positloned~
further along the~beam 4, thus increasing the distance between
securement~ point 22 and shaft 10, however this then obs~tructs a
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1 further area beneath the beam 4 whereby visibility of the
operator is marginally reduced and stress is significantly
reduced. Therefore, the position as shown, which is generally
within about 12 inches of the shaft 10, does concentrate or
provide a high stress area at point of securement 22, however,
for light application, this can be accommodated in the design
of the securement of the link 20 to the beam.
In the embodiment of the invention as shown in Figures
2 through 4, the link 20 has been replaced by a dauble acting
hydraulic cylinder 34 generally universally supported to the
side of the frame 2 of the grader via flange 25. The cylinder
34 has been secured intermediate the length of the barrel
portion 36 to allow for a somewhat greater stroke of the
cylinder. The piston 38 of the cylinder 34 is secured at point
22 to the beam whereby the position of the beam relative to the
mainframe 4 is~accomplished by adjusting the cylinder. This
results in an arrangement which effectively provides an
infinite number of positions of the beam between its extreme
points of rotation, with~the lock~ing of the beam being
accomplished by the hydraulic cylinder 34. It is also possible
to introduce an hydraulic pressure relief switch whereby if
forces are encountered exceedi:ng the~maximum deslgn, the relief
valve would~be actuated momentarily releasing lock cylinder 34
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1 to avoid damage. The hydraulic cylinder 34 thus allows powered
positioning of the beam and does not require the resting of the
blade on the ground to effect adjustment. In most prior art
arrangements, it has been essential to place the blade on the
ground and allow the remaining cylinders to move in response to
repositioning of the beam, with the beam subsequently being
locked, whereafter the other hydraulic components can be
adjusted as necessary. Such is not the case with the hydraulic
control arrangement of the beam of the present invention, as
hydraulic cylinder 34 is under power and allows positioning of
the blade as desired.
A modified arrangement is shown in Figure 5 wherein
the double acting hydraulic cylinder 34 has been relocated and
repositioned to improve the load carrying capabilities of the
components. The double acting cylinder 34a has the piston 38a
pivotally secured to the frame 2 at 21a a~djacent the lower~edge
and to one side of the frame by means of brackets 25a. The
barrel 36a ls~pivot~ally~ secu~red to beam 4~at~35a spaced
outwardly of shaft 10 and to the same side of the frame as
position 21a. The~;point of securement 35a is~selected to
reduce high stress concentrations~and avoid cylinder fouling.
The triangle formed by the position of securement 35a, point
21a~and shaft 10~results in lower stress~than the arrangements
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1 of Figure 1 through 4. This arrangement requires a greater
stroke for cylinder 34a and, therefore, the orientation of the
cylinder has been reversed to extend above beam 4. The lift
cylinder 6 is secured to the side of the beam 4, opposite
cylinder 34a, to minimize the possibility of fouling. Cylinder
34a will always remain in the same plane, whereas cylinder 6
does not.
The arrangement of Figure 5 advantageously separates
shaft 10, securement point 35a and position 21a, to reduce
stress. By having shaft 10 above the frame 4, the distance to
point 21a is increased. Thusj the structural characteristics
are improved, although some loss of visibility is suffered due
to cylinder 34a extending above beam 4. The higher load
carrying capability of the arrangement of Figures 5 through 7
are preferred.
Again, beam 4 may be fabricated of plate~steel in a
box type cross-section, in wh1ch case, ports top and bottom can
be provided and cyl~inder 34a can extend through the~beam 4
The simplified shape of the beam 4 makes fabrication from plate
steel a competitive alternatlve to~a cast beam~.
With the arrangement as shown in the drawings, the
grader blade may be positioned to either side of the mainframe
4 and the blade posi~io~ned at 90 to either side of the
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1 mainframe. Therefore, the support achieves the full
flexibility of prior art systems while simplifying the support
structure resulting in lower manufacturing costs, improved
operating characteristics as well as simplified service in the
field. Furthermore, in the preferred embodiment where an
hydraulic cylinder is used to lock the beam and cause rotation
of the beam as desired, full flexibility in the positioning of
the beam under the weight of the blade is accomplished.
The blade position in the horizontal beam orientation
and rotated for 90 high-lift as well as the blade positions
are shown in Figure 6. Figure 7 is a rear view of a beam of
additional depth and showing details of the mounting of the
hydraulic lock cylinder.
The particular geometry lS shown in Figure 6 and
includes the points of securement of the lift cylinder 6 to the
beam 4, the pivot of the beam, the beam width, the securement
of the drag link 16 to the downwardly depending arm 14 and the
points of securement of the lift cylinders~t~o the beam 7 and
the securement of the drag link 16 to the beam 7. This
geometry~has proven most satisfactory. The beam 4 spaces the
cylinders 6 apart approximately 50 inches at the beam and the
lift cylinders are secured to the beam 7 at a spacing of about
48 Inches. This causes the cylinders to adopt a neutral
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1 position as shown in Figure 6 where the cylinders are initially
angled slightly outwardly to generally follow the progressively
opening window of the cab of the grader. The 50 inch spacing
of the cylinders either side of the beam is substantially
reduced relative to the industry, where a minimum spacing of 52
inches and a more normal spacing of 54 inches have been used.
The narrower spacing of the beam in combination with the
improved clearance beneath the frame and particular location of
the points of securement of the lift cylinders below the axis
10 of the beam (about two inches), or at least in line
therewith, allows the desired positioning of the blade 90
either side of the grader as well as positioning of the blade
for banking at a 2 to 1 or 1 to 1 ratio and a ditching
position. The distance between securement of each cylinder 6
to the beam and the end position of the piston portion of the
cylinder at maximum stroke is about 70 inches. The height of
the cylinder above the beam is such to allow for full
retraction of the piston portion of the lift cy~linder. The
minimum retracted positlon of the drag cylinder 16 is 38 inches
and this cylinder has a stroke of about 27 inchbs. The point
of securement of the drag link~16 to the beam 7 is offset from~ ~ ;
the center l~ine of the beam and the center line of the grader
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about 21~ inches. The spacing of the lift cylinders on the beam
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l 7 again are symetrical about the center line and are separated
48 inches. The upper securement of the drag link 16 to the
depending arm 14 is about 19-1/2 inches below the horizontal
passing through the axis lO and is of~set from the center line
of the beam about 16-l/4 inches. These dimensions are all
center line to center line.
This arrangement allows a full 90 high-lift
position with the blade approximately 21 inches above the
ground and the beam 7 approximately 31 inches above the ground,
and the blade is positioned outwardly of the tires lOl of the
grader such that the far edge of the blade is about 33 inches
from the outer edge of the tire. In order to achieve a 2 to l
bank sloping position, the cylinders are adjusted with the beam
in its fully rotated configuration and this results in the
blade being lowered towards the ground and the lower outer tip
of the blade will~be approximately 6 inches above the ground
and located exteri~or to the tire approximately 20 inches. To
effect a l to l banking sloping operation, the blade moves
inwardly whereby the lower tlp of the blade is approximately lO
inches spaced outwardly of the tlre and again is approximately
6 inches clear of the ground. Therefore, in both the 90
high-lift positions, the 2 to l bank~ing posltion and the 1 to l ~
banking~position,~ the~lower edge of the~blade can be positioned ;;
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1 above the ground for working a bank where any excess material
can accumulate to the exterior of the tire in the gap between
the lower edge of the blade and the tire. Thus, the tire does
not ride on the ridge of material that may accumulate and as
such, a fairly constant slope can be achieved. With the
high-lift in a fully retracted position (solid lines in Figure
6) with the beam horizontally disposed, the bottom of the blade
allows a ground clearance of over 17 lnches and is movable to a
maximum lower position o~ approximately 20 inches below grade.
One of the problems associated with a pivotted beam
high-lift is that~the 90 high-lift position should be
possible elthe~r slde~of the road grader, and in some prior art
arrangements the drag~link 16 has been reversible~in that it is
capable~of~ being~sec~ured~either side of the cente~r of the beam
7 and the~f~rame 2. ;Such~ s~n~ot necessary ln~the~present
structure~where,;~due~to;th~e~part~lcular geometry,~rotatLon~of
the beam~to~the opposite~side a~nd full retraction of the~drag
link~l6~ac~c~ommo~dates~the~90~conflgurat~i~on to the~ oppos~ite;~
sid~e~of~the~gr~ad~er.~Thus,~;to~a~ch~ieve the 90 orientation~to
one~side,~the~;~drsg;~ nk~ls~es~sent~ially~full~y~extended~and to~
achieve~the~90 ~to~t~he~ op~posite side~,~the d;rag~link~16 i~s
essent~islly~fùlly~retrac~ted~
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1 With the hydraulically locked beam shown in Figure 5,
the operator has full flexibility in positioning of the beam 4
for various operations. Specialized applications in the field
can take full advantage of this flexibility, however the normal
positions of bank sloping at a 2 to 1 slope or 1 to 1 slope or
the 9û high-lift either side are possible by fully rotating
the beam to the appropriate end position and then adjusting the
cylinders. By reducing the spacing between cylinders and the
particular securement of the cylinders in combination with the
securement of the drag link, problems, associated with
cylinders reversing over center which create a lock situation
where the cylinders are fighting each other, are greatly
reduced in that the movement of one cylinder generally causes
the other cylinders to move in the desired manner. This
improved cooperation between the cyllnders is achleved due to
the particular geometry of the system.
In the hydraulically locked~ beam of Figures 5 and 7,
several advantages have been achieved~by posltionlng the
securement 39 and ~lock cylinder 36a fairly close to the lift
cylinder 6 and generally tow~ards the end o~ the beam~4. The~
lift cylinder 6 is located to one slde of the beam and does~not~
remain in a vertical plane and r~otates ln certain blade
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positions~over t~he beam.~ By posltioning the cylinder 36a
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1 generally close to the point of securement of the lift cylinder
6, the lift cylinder is displaced forwardly o~ rearwardly of
the hydraulic lock cylinder 36a and this spacing is sufficient
to ensure that these cylinders do not foul. As cylinder 6 does
rotate through a certain angle, the distance moved does
increase as you extend outwardly of the point of securement
and, therefore, positioning of the cylinder 36a at a more
inwardly posltion could result in a fouling situation. The
cylinder 36a preferably has a stroke about 18 inches and is
lo spaced outwardly of the axis 10 approximately 20.75 inches. As
discussed earlierj advantages are achieved by pasitioning the
lock cyllnder 36a towards the end of the beam in that stresses
are reduced;and the cylinder takes a more effective angle with
respect to the frame of the grader. As can be appreciated,
forces carried by ~the cylinde~r result in both horizontal and
vertical loads on the~frame as~opposed to the mare limited
vertical~loads which result when the cylinder is positioned as
shown in Figures ~and~3.
~ When cons~ldering~the geometry referred to above,~ t
should be r~emembered~that~the~downwa~rdly extending arm 14~is~
rearwardly offset approximately~8~inches relative to the~center
line~of the~beam;to redu~ce the chances of fouling an~ provlde
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1 In the fully retracted position of the high-lift with
the beam horizontal, there remains approximately 5 inches of
clearance beneath the frame of the grader. This is a result of
the stroke of the lift cylinder 6 and the relative securement
to the pivotted beam 4 and the fixed beam 7. This clearance is
substantially greater when compared to the structure disclosed
in our earlier patent.
The composite design of the beam, which allows
fabrication from plate steel and allows the hydraulic lock
cylinder 36a to extend through ports 45 and 47 in the beam,
also provides flexibility with respect to selecting an
appropriate shape for the design forces. For example, the
depth of the beam and the fore and aft directlon of the grader
can be increased, and if additional width of the beam from top
to bottom is necessary, then the pivot position of the beam
above the frame of the grader can be increased qnd the width ~f
the beam then increased. Thi~s allows a great deal of latitude
with respect to the shaping of the beam~for~the loads expected~
to be encounte;red. The composlte design also~allows for a
~0 reinforcing of -the beam in the area of securement~of the lock
cylinder 36a merely by addln~g~additional plates~lnteriorly or
exteriorly. These~addlti;onal plates are necessary due to the
weakening of the~beam due to the porting as well as the forces
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1 transferred to the beam by the lock cylinder ~6a. The cylinder
3~a is preferably secured to the beam such that the pivot
position of the cylinder is above the beam as shown in Figure
7. Mounting blocks 49 welded to the top of the beam and a
bearing arrangement 51 securing the lock cyllnder is bolted to
the mounting blocks 4g. This again increases the lever arm and
as such, will reduce the stress level on the axis 10 as well as
securement of the cylinder to the frame and the stress at the
point of securement of the cylinder to the beam. The composite
beam construction simplifies securernent of the downwardly
extending arm 14 and selective reinforcing of the beam to carry
the required force. The beam 4 of Figure 7 is mounted slightly
higher above Prame 2~to accommodate the shallower radius 57
which can be a high st~ress area.
~ A~fabricated beam 4 is preferred, however a cast beam
could also~benePIt;from ~the improved~geometry~and cooperatlon
of component~s. ;~
Although~varlou~s p~rePe~rred embodlm~ents~ of the present
invention have~bee~n~descrlbed~herein~in detail, it will be
appreciated~by those ski~lled~ln the art,~ that variations may~be
made thereto without departing~f~rom the spirit of the invention
or the sc~ope;oP~the~appende;d cl~a~ims.~
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