Note: Descriptions are shown in the official language in which they were submitted.
9~r3
~IELD OF THE INVENTION
The present invention relates to devices for scarifying
and levelling gravel roadways, parking lots, and the like.
BACK~ROIJND OF T~IE IN~I~NTION
Gravel roads, gravel shoulders, gravel parking lots,
all exemplify the use of gravel in economically facilitating both
vehicular and pedestrian traffic over defined areas and routes.
For various reasons, the use of gravel in these applications can
be very much more attractive than the alternatives afforded by
asphalt and concrete paving.
The use of gravel, however, is not without its own
complications. Uneven compaction over the travelled surface can
lead to the formation of wheel ruts, while turning, accelerating
or deceler~ting traffic can lead to local phenomenon such as
potholes and corrugations; and, the aggregate material will
itself tend to undergo a sorting, by particle size, attributable
to differential compaction effects, the results of all of which
are less than attractive. In some cases, these effects represent
safety hazards.
One solution to the degradation of such gravel
emplacements has been to simply add additional gravel over the
surface, as needed. Interestingly, there is only a limited
consolidation between the added material and the underlying
surface, which tends to leave the upper, relative.ly
unconsolidated material in an easily disturbed layer from which
aggregate material tends to be rapidly displaced. Moreover,
commercial sources of aggregate depend of naturally occurring
gravel deposits, and like most natural r~sources, their numbers
are becoming depleted. Although the existence of many more
marginal deposits stave off any likelihood of critical shortages
of supply, the costs of harvesting a more marginal deposit is
inherently higher, and this is reflected in higher gravel costs.
As a conse~uence, the historical practice most often
adopted to remediate gravel roads, parking lots and the like,
have entailed the use of large, powerful road graders, equipped
with scarifiers. A g~ader is, by definition, a machine with a
centrally located blade that can be angled to either side.
Typically, graders have a reinforced tubular or box-beam "Y"
frame supporting the engine at the rear of the vehicle, between
the arms of the "Y". Drive wheels, usually arranged in tandem,
are positioned below the engine and transmission,, while steering
wheels are arranged on an axel system at the point of the "Y"
frame. The major attachments for the grader are secured in
downwardly hung relation from the overhead portions of the frame,
and are pulled by a drawbar reaching back from the front of the
frame. These attachments include the blade and the scarifier.
More specifically, the blade is arranged on a toothed
ring gear called the "circle", on which the attachments can be
rotated. An arm-type attachment between the "circle" and the
frame allow the circle to be controllably lifted, lowered, offset
to either side, or even to be placed into a vertical
configuration. The scarifier is typically position in ~ront of
the blade, and is carried on a pair of arms that reach back from
the front end of the graders frame. The scarifier can be raised
and lowered to regulate the depth of penetration, relative to the
bottom of the graders tires. The number of teeth used on the
scarifier is dependent on the hardness of the surface being
worked.
Attempts at smaller scale scarifiers have been
unsuccessful from a performance point of view, and have not
enjoyed commercial acceptance. One such attempt took the form of
a towed "box scarif~er". This consisted of a scarifier and a
plough blade arranged at opposed ends of a frame which a had a
box shaped plan. The device was drag~ed along by a vehicle with
the intention that the scarifier would turn up the underlying
aggregate and the plough blade would evenly redistribute it.
Unfortunately the device was neither heavy enough to scarify
properly, nor did it afford the control necessary to evenly
redistribute even such material as was dislodged by the scarifier
teeth. The problem is similar to that encountered with very
early attempts to use towed road construction rippers, the use of
which has now apparently been abandoned. Towed rippers too,
proved to be unsatisfactory do to poor penetration. If
sufficient weight was added to the towed ripper to insure
effective penetration, the ripper became too heavy for any but
the largest of commercial tractor vehicles. These towed rippers
were also rather unwieldy, and hard to manoeuvre. Lastly, such
s
rippers were not grading devices, and are simply a battery of
teeth mounted on a wheeled vehicle.
Towed graders were also known. These were produced in
an attempt to deal with a number o~ grader-related problems, but
are now considered outmoded. Their use required two skilled
operators, which was an offset to the presumed adva~tage of
reduced capital and maintenance costs. They were in any case,
found to be hard to manoeuvre even relative to motorized graders,
and were never known to be used in scarifying operations. There
is the further problem that the tow vehicle tends to compact the
material that the to~ed grader was intended levelingly
redistribute.
Accordingly, the only known commercially viable
practice continues to rely on the use of motorized graders.
Graders provide sufficient weight and power to force the
scarifier teeth into the ground and drag it along, together with
the control necessary to position a grader blade for proper
redistribution of the dislodged materials.
The problems that are and have always been lmmediately
apparent in connection with the use of graders for this purpose
continue to be a problem, however. These include a requirement
for a highly skilled operator. Moreover, graders are not highly
manoeuvrable, a problem which is a function of the very size and
weight heretofore thought necessary to achieve scarifying/grading
operations. Moreover, the economics of grader operation are very
sensitive. For example, according to "HEAVY CONSTRU~TION -
Equipment and Methods" - by Stuart Wood Jr., points out that
straight line grading patterns that cover less than 1000 linear
feet, are economically inefficient because of the operating/time
costs associated with turning the grader around. Even were the
economics otherwise, the large siza of graders make them
difficult or even impossible to manoeuvre in the manner necessary
to service the close quarters that characteriæe many gravel
emplacements. The travelling costs of grader equipment are very
high, and some jobs are often not done at all particularly if
they are in geographically isolated areas.
SUl~M~RY OF TXE INVENTION
In accordance with one aspect of the present invention,
-there is provided a scarifier which comprises a plurallty of
supported, downwardly depending, axially secured scarifying teeth
having substantial lateral free play at respective scarifylng tip
ends thereof. It has been found, and this finding forms one
basis for the present invention, that the lateral free play o~
the scarifying teeth tips improves the scarifying ability of the
device. Embodiments of the present invention have been found to
lo satisfactorily remediate gravel traffic courses when, in
accordance with the ~resent invention, scarifiers are use in
combination with light,low powered utility tractors, connected
through a three point hitch. The thusly equipped vehicle is
highly manoeuvrable, easy to operate, requires only a relatively
moderate capital outlay, and unlike a grader, which is a
relatively special purpose vehicle, the tractor can be readily
employed to other ends.
The scarifier of the present invention can include a
scarifying-tooth supporting frame adapted to be connected in
loose fitting r~lation to a driving means, to thereby operatively
impart lateral play at respective scarifying tip ends. In an
exemplary embodiment, the supporting frame has a bracket means
adapted to engage respectlve shank portions of the downwardly
depending plurality of scarifying teeth. The bracket thereby
holds these teeth in axially secured relation, but with
~ s3
sufficient degrees of lateral freedom to provide lateral play to
spaced apart scarifying points of respective ones of the teeth.
In another general aspect, the scarifier has a
scarifying-tooth supporting frame that is adapted to be connected
in loose fitting relation to a driving means to thereby
operatively impart a first component of lateral play at
respective scarifying tip ends. Such a frame preferably also
includes bracket means adapted to engage respective shank
portions of the scarifying teeth in axially secured relation with
sufficient degrees of lateral freedom to provide a second lateral
play to spaced apart~scarifying points of respective ones of the
teeth.
Teeth useful in the practice of the present invention
include those which comprise hardened tips arranged on unhardened
shanks. In any case, teeth are preferably arranged in an array
of pairs comprising corresponding ones of leading and trailing
teeth. In an especially preferred form the leading teeth extend
to a first operating depth, and the second teeth extend to a
second, greater operating depthO While this can be accomplished
by utilizing teeth of different lengths, it is preferred that
this result be controllably realized through pitch orientation
control of the scarifier as a whole, whereby the angle of attack
positions the leading and trailing teeth at different respective
heights relative to the surface being scarified.
In one form, the teeth comprise a scarifying tip
arranged in axially spaced relation along the shank from axial
9~1'i
interference means thereon, the :interference means being adapted
to operate in axially interfering relation aga:inst a portion of
the frame. In this arrangement, a preferred bracket can be used,
which comprises a pair of plates including a first plate adapted
to receive shank portions of onas of the teeth through
corresponding ones of openings extending through the first plate.
These openings receive the teeth in surroundingly loose fitting
relation about the shank, with the tip extending below a lower
side of the plate and the axial interference means extending
above an opposite upper side of the first plate. A second plate
on this bracket is a~apted to be secured in fixed, spaced apart
relation above the upper surface of the first plate. The axial
interference means is thereby secured between the first and
second plates.
In especially preferred forms of the present invention,
the scarifier is adapted to controllably position the teeth at
selected elevations relative to a work surface. Also, it is
preferred that the scarifier include means adapted to position
the teeth to follow a work surface contour, in constant weight
transferring relation with the surface. This helps to maintain a
relatively consistent load on the driving vehicle, and makes it
generally easier to maintain a constant speed over the work
surface. Conventional draft control systems can be used for this
purpose. Also, means for controllable positioning of the frame
in selected attitudes relative to a work surface can facilitate
the scarifying operation. This includes the ability to
controllably position the attack angle attitude of the frame, and
to controllably position the pitch attitude of the frame.
In accordance with another aspect of the present
invention, there is provided a scarifier/grading device
comprising in combination:
a scarifier (at least one, although more than one
may be used in tandem if desired), including a
plurality of scarifying teeth borne thereon;
a grading blade having a mold board and a cutting
edge;
a seco~d frame interconnecting the scarifier frame
and the blade in mutually spaced apart relation with
the scarifier in operably leading relation and the
blade in operably trailing relation,
wherein the scarifier includes height-adjusting means for
selectively raising and lowering a plurality of scarifying teeth
borne thereon relative to the cutting edge. Preferably the
height-adjusting means comprises an at least one hydraulic
cylinder~
Consistent with the interest in enabling the scarifying
ope~ation to be carried out utilizing light weight, relatively
low powered tractors, it is preferred that the blade has a
concave shaped, leading mold ~oard surface. This surface shape
increases the load carrying capacity of the blade, by rolling the
material captured by the blade is lifted, and then rolled
forwardly. This keeps an inventory of material before the blade,
and available for levelling out minor irregularities that the
blade passes over. It is also preferred that the second frame be
open-sided to thereby permit the egress of excess substrate
material collected on the blade. This allows the blade to
continue to operate efficiently in facilitating the levelling
operation, and without overloading the vehicle through the
accumulation of excess mass in front of the blade.
In accordance with the present invention, there may be
included a plurality of grading blades, which can facilitate
special grading functions. For example, the grading of a roadway
with a crown, the le~ding blade is preferably adapted to direct
the scarified material outwardly towards the centre of the
roadway, to a point where it is deposited in the path of the
foremost end of a sidewardly offset, trailing blade, which is
adapted to capture and partially redistribute the materlal back
towards the shoulder of the roadway, to achieve an appropriate
crown profile. This is accomplished by having the two blades
arranged at mutually offset angles to one another. The device as
a whole is made more flexible in embodiments in which the offsek
angles are independently controllably selectable.
Note that the typical application of the last
abovementioned aspect of the present invention entails operating
the device with the scarifier in the lead of the plough. The
device may be employed bidirectionally, however, if desired or
necessary, and this can be accomplished with particular facility
in embodiments wherein the plough is adapted to facilitate
~q3~3~
bidirectional ploughing, and the combination allows for selective
relative positioning of the scarifier and the blade.
In especially preferred embodiments of this aspect of
the present invention, there is provided means adapted to
s selectively position the device at a desired elevation relative
to the work surface. Moreover, means for seleetively controlling
the attitude of the device relative to a work surface is
desirable. Attitude eontrol means adapted to selectively pitch
of the deviee is one example of this facility. Angle of attaek
is another attitude eontrol means which is highly preferred.
In an espec-ially preferred form, the deviee in
accordance with the practiee of the present invention takes the
form of a removable attaehment device. In an espeeially
preferred form sueh an attachment device is adapted to be
reeeived in attaehed relation on a three point hitch. The three
point hitch is then operable to provide elevation control over
the attaehment. In an espeeially preferred form the three point
hiteh has a centre link whieh eomprises a hydraulie eylinder
operab]e to seleetively eontrol the attack angle. Similarly, a
preferred three point hiteh is one in whieh at least one of the
lift lin~s comprises an hydraulie eylinder operable to
seleetively eontrol the piteh angle of the deviee.
In this l~tter eonnection therefore, the present
invention further extends to a three point hiteh in which
attaehment pitch control means comprises a rock shaft hingedly
eonneeted to lift arms, intereonnected through lift links to
2 ~ 3 ~J~j
draught links in "third" class lever relation; wherein one of the
lift links is an hydraulic cylinder. In a preferred form a
telescoping shaft extends in interconnecting relation between the
draught arms, and includes a sleeve for connecting the lift link
comprising an hydraulic cylinder operable to be controllably
lengthened and shortened to change the pitch of an attachment.
As already mentioned hereinabove, the centre link preferably
comprises an hydraulie eylinder.
In an especially preferred aspect of the present
invention there is provided a scarifier/grader apparatus
eomprising, in eombi~ation, a tractor eonnected through a 3-point
hiteh to a scarifier/grader attaehment wherein:
the tractor is adapted to be operably
eonneeted through a three point hitch to a
searifier/grader attaehment comprising a
scarifier ineluding means for raising and
lowering a plurality of scarifying teeth
borne thereon;
a grading blade having a mold board and a eutting
edge;
a second frame interconneeting the searifier frame
and the blade in mutually spaeed apart relation with
the scarifier in operably leading relation and the
blade in operably trailing relation,
~3~
wherein the scarifier includes height-adj~lsting means for
selectively raising and lowering a plurality of scarifying teeth
borne thereon relative to the cutting edge.
In addition to scarifying qravel traffic areas, the
present invention is useful in, inter alia, landscaping
applications. Although applicable in other uses, a feature in
accordance with one aspect of the present device that is useful
in landscaping applications, is a biclirectional plough blade
comprising a structural beam orientecl in a horizontal p]ane, and
forming a mold board, with a cutting edge arranged on an edge-
supporting portion of the blade that is attached to, and extends
in a vertical plane beyond either side of the bottom of that
beam.
As will also be apparent to the person skilled in the
relevant arts, the present device can be employed in conjunction
with laser guided hydraulic control systems.
~'q3~ 3~'3
DETAILED DESCRIPTION O:F A PREFERRED E~lB!:)DI~ENT
Introduction to the Drawings
Over the course of the detailed description which
follows hereinbelow, reference will be made to the appended
drawings, in which:
Figure 1 is a perspective view of a preferred
embodiment of the present invention, showing a combination
scarifier/levelling blade attachment;
Figure 2 is an elevated side view of the attachment
illustrated in Fiyure 1, shown in operative combination with a
modified three point~hitch, also according to the present
nventlon;
Figure 3 is an exploded perspective view of a bracket
assembly for a scarifier according to the present inventioni
Figures 3a and 3b are exploded perspective and cross-
sectional end views, respectively, of an alternate bracket
according to the present invention;
Figure 4 is an elevated sectional, side view
illustrating the combination of the scarifier and blade depicted
in Figure l;
Figura 5 is a rear perspective view of a conventional
three point hitch arranged on the back of a utility tractor;
~ igure 5a is a top plan view of the combination
scarifier/blade attachment shown in Figure 1, in combination with
attached portions of a modified three point hitch according to
the present invention; and,
;~3~ 3si11
Figure 5~ is a view o~ the telescopically positionable
interconnecting shaft that extends between the two draft links of
an especially preferred modified three point hitch in accordance
with one aspect of the present invention.
Referring now to Figure 1 of the drawings, there is
depicted a scarifier 1 comprising a plurality of teeth 2,
including respective tips 3, supported by a supporting frame 4
which includes a bracket means 5. The scarifier 1 includes
height adjusting means in the form of a pair of spaced apart
hydraulic cylinders 12a and 12b which are operably connected
between an overhangin-g horizontally extending member ~a, and
bracket means 5 which is slidably arranged in vertically
extending channels formed in vertically extending frame members
4b. The illustrated embodiment includes, in combination with
scarifier 1, a blade 13 having a mold board 14 and a cutting
blade 15. These are fixedly secured to scarifier 1 through a
second frame 16 that is rigidly co-joined to supporting frame 4.
Openings 17 in the sides of second frame 16 provide for the
egress of excess scarified materials from in front of blade 13,
so as to make the load manageable. Blade 13 also includes a
trailing shoe 26 which can be usefully employed in free floating
the blade during levelling operations, as will be apparent to
persons skilled in the art in light of the present invention. In
this frame arrangement, the scarifier 1 and the blade 13 are co
operable in a mutually dependent relation, that is
distinguishable from the mutually independent operation of
3~
scarifiers and grading blades used on graders. One advantage of
the present invention in this respect is the greater ease with
which the scarifier and plough can be cooperatively oriented,
particularly when the device is employed by a relatively
unskilled operator. In addition, the present device can be
readily connected in tandem with a compaction device, such as a
roller, through a tow bar or tongue affixed to the rear of the
device, to accomplish the complete surface conditioning task in a
single pass, when conditions permit.
Figure 2 of the drawings depicts the device according
to Figure 1, in an e~evated cross sectional view which emphasises
the three point hitch connections preferred herein. More
specifically, there is illustrated a three point hitch and
scarifier/blade attachment in interconnected relation. In
accordance with this preferred practice, the vertical frame
member 4a is interconnected through a pivot attachment point 19b,
to a centre link hydraulic cylinder l9a. More particularly, it
is preferred that connection point l9b include a bracket
extending from frame member 4aj, that includes oversize holes
adapted to receive an undersized connection pin. In the
exemplary embodiment a one and one quarter inch diameter hole
accommodates a one inch diameter pin. The pin is thereby adapted
to co-join the cooperative terminus of cylinder 19a, through the
bracket in question, to frame member ~a, with sufficient degrees
of freedom to afford lateral displacement of the teeth in the
manner earlier mentioned herein. In like manner, oversize
i
16
wholes/undersized pi.ns are used inte~nediate connection points
l9c, between the respective draught links 23 and corresponding
ones of vertical frame members 4b. Byu way of example, generally
circular bracket holes of about one inch in diameter, are used in
conjunction with generally cylindrical pins having an outside
diameter of about three quarters of an inch.
The lateral freedom mentioned above can additionally or
alternatively be provided by way of clearances in the fitting of
teeth 2 on bracket 5. Referring now to Figure 3 in particular,
one form of bracket 5 is illustrated in an exploded perspective
that reveals holes 1~. These holes 11 are arranged in an array
that is adapted to receive respective ones of leading and
trailing teeth 2a and 2b, and so as to provide a range of from
about 1/16 to 3/32 of an inch clearance between the ed~es of
holes ll and the adjacent portions of the teeth shanks 6. A
crown 8 provides axial interference means on teeth 2, that limit
the axial passage of teeth 2 through corresponding ones of holes
ll. Plate 10 is adapted to be received, with teeth 2 positioned
in holes ll, in overlaying relation above plate 9. The two
plates are bolted together with bolt lOa and nut 9a, to
clampingly engage the axially interferiny portions 8 o-f the
teeth, between the two plates.
In one variation a bracket 5a, as depicted in Figures
3a and 3b, which includes a lower plate 9c constructed out of a
pair of channel members 9d and 9e, which when assembled are
mutually fastened together by welds extending along mutual
~3~1~S
contacting surfaces thereof. More particularly, channel member
9d includes holes lla which are adapted to receive adjacent shank
portions of corresponding teeth, with about a sixteenth of an
inch of play between the edge of the holes, and adjacent surfaces
of the shank. Holes llb in channel memher 9e, on the other hand,
provide a corresponding clearance of about 3/32 of an inch. The
resulting "constrained pivotal" support of the teeth 2 by bracket
5a provides the requisite lateral freedom referred to
hereinbefore. Bracket 5a also includes and angle member lOb
which is adapted to be engaged in bolted overlaying relation on
plate assembly 9c, to thereby trap the axial interfering crowns
8, therebetween, as can perhaps best be seen in Flgure 3b of the
drawings. Rounded upper surfaces of crowns 8 can advantageously
facilitate a rocking motion when fixed in this clamped relation
between the two plates.
Figure 4 of the drawings illustrates the cooperation of
the scarifier and blade of the present invention. Note that the
operation of cylinders 12a and 12b provide for height adjusting
means, whereby the depth of the scarifier can be varied relative
to the blade position. In attachments according to the present
invention which are adapted to be secured in combination to other
positioning apparatus, and whereby the blade and the scarifier
are responsively co-positionable, there is provided the
operational advantages already mentioned herein.
Referring now to Figure 5 of the drawings, there is
depicted a conventional three point hitch 18 comprising a centre
18
3~
link 19 connected at one end to a general utility tractor, as
viewed from the rear thereof. A rock shaft 21 is hingedly
connected to lift links 20, which are hingedly connected at
opposite ends thereof, in third class lever relation, to pivotiny
draft arms 23. Such a three point hitch is advantageously
operable in combination with scarifier, and scarifier blade
attachments according to the present invention. Further
positioning control and operational flexibility can be realized,
however, through the use in the abovementioned combinations of a
modified three point hitch, such as that illustrated in Figure 5a
of the appended draw~ngs.
Referring in that connection to Figure 5a, there is
illustrated a modified three point hitch wherein an at least one
lift link comprises a selectively operable hydraulic cylinder 20a
connected to a corresponding at least on draft link 23.
Preferably, the modified three point hinge comprises a
telescoping interconnecting shaft 24 that extends between the two
draft arms 23. Such a shaft, is illustrated in detail in Figure
5b, and includes a first shaft 24a that is received in slidable
telescoping relation within a second shaft 24b. This facilitates
adjustment of draft arm spacing, as may be re~uired to facilitate
attachment of the present device to a wide range of tractors. In
addition, shaft 24 includes a slidably positionable sleeve onto
which one end of cylinder 20a is secured. This arrangement
permits the apparatus to be readily set up so that the radius of
hydraulic lift link 20a matches the operating radius of the oth2r
19
2~
lift link 20. Once the sleeve is so positioned, lt is fixedly
secured to the shaft 24, prior to prassing the apparatus into
service. In the illustrated combination, centre link l9a
provides control over the pitch of the attachment, which can be
used to co~vary the relative vertical positioning of the
scarifier teeth tips relative to the blade tip. Hydraulic lift
link 20a is operable to vary the side to side pitch of the
attachment, which is useful in producing surface contours such as
crowns on roadways, or the like.
Referring now to the drawings in general, there is
illustrated an attachment in accordance with the present
invention, which comprises, in combination, a modified three
point hitch, a scarifier and a plough, which is operatively
connected to a suitable vehicle, such as the earlier mentioned
utility tractor. In operation, the scarifier teeth 2 are
positioned relative to the ~lade tip 15, to result in
simultaneous and ccntrolled scarification depth/ and loosened
aggregate levelling operations. This is facilitated through the
selective retraction and extension of cylinders 12a and 12~.
Side to side pitch of the apparatus is varied through
the selective extension and retraction of hydraulic lift link
20a, while the height of the apparatus/or the amount of downward
pressure exerted through the three point hitch by the tractor, is
controlled in conventional manner by the selective positioning of
the rock shaft 21. Draft and contour controls of known type, co-
3t~
operable with the rock shaft positioning, can also be utilized in
this combination.
The angle of attack of the working surfaces of the
apparatus can be selectively varied through extension and
retraction of hydraulic centre link l9a.
As the tractor is driven along, the attitude of the
apparatus is readily adjustable through the selective operations
of the rock shaft 21, the centre link l9a, the lift link 20a, and
the cylinders 12a and 12b, with the end result that the
attachment provides for highly adaptive and versatile surface
treatment. -