United States Patent
`Swisher, Jr. et al.
`
`(19
`
`[14]
`[45]
`
`4,140,420
`Feb. 20, 1979
`
`
`3,846,035 11/1974—Davita ..cescescccssseesseessessseeeeses 404/84
`[54] PORTABLE GRADE AVERAGING
`
`
`3,879,149cesseseens 404/84 X4/1975) Smith
`
`APPARATUS
`
`4,029,165=6/1977 Miller o...sseceeeseeeesseenensesees 404/84 X
`8/1977) Miller oo... eee seeesceneneneee 404/84 X
`4,041,623
`(75]
`Inventors: George W. Swisher, Jr.; Thomas L.
`Steele, both of Oklahoma City, Okla.
`[73] Assignee: CMI Corporation, Oklahoma City,
`Okla.
`
`Primary Examiner—Nile C. Byers, Jr.
`Attorney, Agent, or Firm—Dunlap, Codding &
`McCarthy
`
`[21] Appl. No.: 887,004
`
`[22] Filed:
`
`Mar. 16, 1978
`
`[SU]
`Tint, C12 ceecccccccccccssssssssncessecesecereeeeesee EOIC 19/00
`
`[52] US. Ch. cee ececeseenenceeneeeee 404/84; 37/108 R;
`37/DIG.1; 172/4.5; 180/9.5; 180/41; 280/6.1;
`299/56; 299/1
`[58] Field of Search... 404/84; 299/56, 1;
`37/108 R, DIG.1, DIG. 20, DIG. 14; 172/4.5;
`180/9.5, 41; 280/DIG. 1, 6 R, 6.1, 6.11
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`ABSTRACT
`[57]
`A portable grade averaging apparatus comprising an
`averaging bar assembly that serves as an elevation con-
`trol reference for a track supported road working ma-
`chine, one end of the averaging bar assembly being
`pivotally supported by a forward walking beam and the
`other end of the averaging bar being pivotally sup-
`ported by a rear track assembly that serves as a track
`walking beam. A grade sensor assembly supported on
`one side by the road working machine contactingly
`engages the averaging bar assembly for directing the
`elevation of one side of the road working machine to
`establish the elevation of a working tool supported by
`
`3,111,070 11/1963=Polllitz occ ecceseeeeeereneee 404/84
`the road working machine. A lifting bracket supported
`
`3,272,099=9/1966=Drake oo... eseesceeeeseessetenaee 404/84
`by the road working machine servesto lift the grade
`3,323,427
`6/1967
`Schrimper..........
`eres 404/84
`averaging apparatusinto a grade clearing position while
`
`3,595,144—T/DOTL —-Ritk nc csescssscsestcsessessereneneane 404/84
`the machineis being maneuveredinto a cutting position.
`3,771,892
`11/1973
` Munyon .......seeeeceeesnsscseneees 404/84
`3,807,887
`4/1974
`3,811,787
`
`
`
`5/1974
`
`21 Claims, 4 Drawing Figures
`
`
`
`Page 1 of 10
`
`CATERPILLAR EXHIBIT1051
`
`CATERPILLAR EXHIBIT 1051
`
`Page 1 of 10
`
`

`

`U.S. Patent
`
`Feb. 20, 1979
`
`— 4,140,420 ©
`
`
`
`het
`(Go es
`KetLIS.
`
`
`
`“Nie
`
`2
`
`33 Al ==" :
`me"| LieoLi
`
`Page 2 of 10
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`Page 2 of 10
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`

`

`i
`
`- 4,140,420
`
`2
`piece at a predetermined working depth. However,
`_Since the grade elevation sensor assembly senses the
`grade elevation of the roadway forwardly of the work
`piece, the work piece will generally be maintained at a
`. working depth indicative of the average elevation for-
`-ward ofthe work piece as opposedto the average grade
`elevation surrounding the work piece. Thus, the result-
`ing finish grade formed via the work piecewill not be as
`uniform as if the work piece had been positioned at a
`. working depth indicative of the average gradeelevation
`of the roadway near the work piece.
`An additional problem with conventional portable
`- walking beam assembliesis that they restrict the maneu-
`verability of the road working machine. In the use ofa
`road working machine employing a planing cutter, by
`way of example, the machine frequently must make
`multiple cutting passes along the roadway. At the end
`of each pass, the machine must be manuevered into
`position to make the next cutting pass. It is not unusual
`to find that the machine must be turned around and
`repositioned to travel in the opposite direction, and
`such turn around often must be performed in tight quar-
`ters having minimum clearance and maneuvering room.
`When a conventional portable control reference appa-
`ratus is attached to the road working machine, more
`turn around area must be provided in which the ma-
`chineis repositioned, or the control reference apparatus
`must be removed before turning the machine, and re-
`mounted once the machineis repositioned.
`
`SUMMARYOF THE INVENTION
`Thepresent invention provides a portable grade aver-
`aging apparatus for providing an elevation control ref-
`erence that is adjacent a work piece and whichis con-
`tinuously contacted by a grade sensor, the elevation
`control reference being indicative of the average grade
`of selected surfaces near the work piece. More particu-
`larly, the apparatusutilizes a rear drive track of the road
`working machine substantially as a track walking beam,
`as well as a forward walking beam positioned forward
`of the work piece, with an averaging bar pivotally sup-
`ported by the forward walking beam and the track
`walking beam. The rear drive track provides a rear
`elevation reference indicative of the average gradeele-
`vation rearwardly of the work piece, and the forward
`walking beam provides a front elevation reference in-
`dicative of the average grade elevation forward of the
`work piece, with the averaging bar generally providing
`the elevation control reference indicative of the average
`of the rear elevation reference and the front elevation
`reference. The apparatusis supported by the rear drive
`track at a disposition clear of the nearby terrain, and a
`lifting bracket supported by the road working machine
`disposes the grade averaging apparatusin a gradeclear-
`ing position when the machine is being maneuvered into
`a cutting position.
`Accordingly, it is an object of the present invention
`to provide a grade averaging apparatus connected to a
`road workingmachine such that a portion of the road
`working machine forms a walking beam for the grade
`averaging apparatus, providing an elevation control
`reference indicative of the average of the grade eleva-
`tions forwardly and rearwardly of a work piece con-
`nectedto the road working machine.
`Anotherobject of the presentinventionis to utilize at
`least one of therear drive tracks of the road working
`machineasa grade averaging portionof the grade aver-
`aging apparatus.
`
`PORTABLE GRADE AVERAGING APPARATUS
`BACKGROUNDOFTHE INVENTION:
`1. Field of the Invention . oO
`Thepresent invention relates generally to road'work- -
`ing machinesand, moreparticularly, but. withoutlimita-
`tion, to an apparatus for providing a portable elevation |
`control reference.
`2. Prior Art
`When a road working machine having a work piece,
`such as a planing cutter,is utilized to perform a surfac-
`ing operation on a roadway, such as a surface planing
`operation, an elevation control reference may ‘be dis-
`posed along the roadway and adjacent the work piece
`when the finished surface is to have a predetermined.
`elevation. One of the more commonmeansforestablish-
`ing an elevation control reference is a conventional
`stringline setup positioned alongsidethe roadway. Sens-
`ing means on the road working machine continuously
`senses the predetermined elevation of the stringline
`above grade and providesan elevation control signal 'to
`elevation control means on the road working machine.
`In turn, the elevation control means maintains the work
`piece at a predetermined working elevation, or cutting
`depth, in relation to the grade of the roadway. Thus; a
`uniform finish grade can be formed which is substan-
`tially free of high or low spots. In some instancés, an
`existing curb alongside the roadway may-beutilized in
`place ofa stringline as the elevation control reference, if 30
`the grade elevation of the curb is generally uniform in
`relation to that of the roadway.
`Stringline setups have more than proved their worth
`whenutilized as an elevation control reference for mak-
`ing an initial pass down the roadway.It is relatively
`simple to constructa stringline setup along the shoulder
`portion of a roadway in a manner convenient. to the
`positioning of the sensing means. However, as subse-
`quent passes are made along the roadway,it becomes
`highly impractical to utilize the initial stringline setup,
`and it is not economical to construct a separatestring-
`line setup for each pass madeby the road working appa-
`ratus. This is particularly true when the roadway is
`relatively wide.
`4
`There are also many occasions when a planing opera-
`tion is required to remove a specified amount of mate-
`rial from an existing roadway. An example would be a
`planing specification that requires the removal of the
`surface to a specified depth measured in inches below
`the existing roadway surface.
`Whether the roadway working machineis to.remove.
`surface material by referring to a stringline or to the.
`existing surfaceitself, itwould be desirable to have an
`elevation control reference which is portable, or which,
`more orless, is always positioned adjacent the sensing
`means. Although not meeting this description, walking.
`beam assemblies connected alongside a road working
`machine havebeen utilized in someinstances to provide.
`an elevation control reference whichis roughly indica-
`tive of the desired finish grade. A walking beam assem-
`bly of this latter type is disclosed in US. ‘Pat. No.,
`3,414,327, issued to Austin.
`In the Austin patent, a grade elevation sensor assem-.
`bly is utilized for determining the average grade eleva-
`tion of the roadway forward of the work piece. The
`grade elevation sensor assembly provides a control
`signal indicative of this average grade elevation, and the
`control signal does substantially maintain the work
`
`20
`
`25
`
`35
`
`40
`
`45
`
`350
`
`33.
`
`65
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`Page 3 of 10
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`3
`Yet another object of the present inventionis.to pro-
`vide a self-storing, portable grade averaging apparatus
`that affords greater maneuverability for the road work-
`ing machine.
`A further object of the present invention is to provide
`a portable grade averaging apparatus that is simple to
`construct and manufacture, and which requires mini-
`mum upkeep andrepair.
`Other objects, advantages and features of the present
`invention will become apparent from the following
`detailed description when read in conjunction with the
`accompanying drawings and appended claims.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`4
`grade sensor assembly 22B corinected to the frame 18
`and supported adjacent the work piece 20 near the
`opposite, or right, side 24 of the frame 18; and an eleva-
`tion control assembly-25, connected to the frame 18 and
`having portions connected to the drive assembly tracks,
`as will be describedmore fully below.
`The frame 18 substantially includesthe chassis, body
`panels and, in general, all of the supportive and protec-
`tive portions and components normally associated with
`a road working machine such as the machine 10.
`The working piece 20 is rigidly attached to the under-
`side of the frame 18 and extends generally transversely |
`to a medial portion of the frame 18, and therefore the
`workpiece 20 also extends generally transversely to the
`roadway14. The elevation of the work piece 20, which
`is the portion of the road working machine 10 that
`interacts with the roadway 14,
`is. determined by the
`elevation of the frame 18. Of course, the type of surfac-
`ing operation performed on the:roadway 14 by the road
`working machine 10 is determined bythe kind of work
`piece utilized.
`In one embodiment of the present
`invention, as
`shownin FIGS.3 and.4, the work piece 20is in the form
`of a drum type planer apparatus 28, such as that dis-
`closed in the-above mentioned U.S. Patent Application
`Ser. No. 672,326. A planer housing 30 is disposed over
`the planer apparatus 28 to contain road material cut-
`Referring to the figures in general, and to FIGS. 1
`tings produced via the planer apparatus 28 and to form
`and 2 in particular, shown therein is a road working
`a supportive means for other components of the present
`machine 10 assembled in combination with:a grade
`inventionto be discussed below.
`°
`averaging apparatus 12 constructed in accordance with
`As shown in FIG. 2, the drive assembly 21 is con-
`the present invention. The road working machine 10
`nected to the frame 18 ‘for moving the frame 18 in a
`that is shown is a planer apparatus that is generally
`forward direction 32 and generally includes a conven-
`utilized to perform surfacing or resurfacing operations
`tional prime mover 19, power transmission means (not
`on an existing, or old, grade 13 of a roadway 14. The
`detailed), a front drive track assembly 33, and left and
`grade averaging apparatus 12 is utilized to provide a
`right rear drive assemblies 34A,34B connected to oppo-
`first elevation control reference generally indicative of,
`site sides of the frame 18. For purposes of the present
`or proportional to, a selected surface whereby a new
`invention, the rear drivetrack'assémblies 34A and 34B
`surface, or finish grade 16, is formed, as will be made
`more clear below. In the interest of simplifying the
`are pivotally connected’ to the frame 18 so as to be
`pivotable about a rear control. axis 36 disposed rear-
`drawingsincludedin the present disclosure, details such
`wardly ofthe work piece 20, and for convenience of
`as hydraulic conduits, electrical lines, and machine con-
`trols have not been shown as such are conventional and
`description herein, the’ rear drive track assemblies 34A,
`34B will be referred to respectively as left and right rear
`need not be described for purposes of this disclosure.
`©
`drive track assemblies, said designations arbitrarily as-
`Anillustrative example of a conventional road work-
`signed from theperspective of an‘ operator of the ma-
`ing apparatus such as the machine10is disclosed in the
`chine 10facing in the forward ‘direction32.
`U.S. Patent Application Ser. No. 672,326, entitled “A
`Eachofthe rear drive track assemblies 34A and 34B
`Method and Apparatus for Planing a Paved Roadway”,
`has a ground contact-portion 38:whichis in continuous
`assigned to the assignee of the present invention. Even
`driving contact with a surface portion of the roadway
`though the present invention is particularly applicable
`14 as the frame 18 is moved in the forward direction 32
`to the planing of a paved roadway, as wili be made
`by the drive assembly 21. The ground contact portion
`more apparent below, it should be noted that the pres-
`38 is further characterized as having a leading end 40
`ent invention is also applicable to other roadway: sur-
`andatrailing end 42. The distance between the leading
`face operations such as grading, for example. Further-
`end 40 and the trailing eiid 42 (that‘is, the length of the
`more, as should be clear toone’skilled in the art, even
`ground contact portion’'38)defines the effective span of
`though the road working apparatus related to the above
`the respective reardrivetrack assémblies34A and 34B.
`mentioned patent application is disclosed therein as
`Furthermore, each of the rear drive track assemblies
`being utilized for planing a paved roadway,it is contem-
`34A and 34Bis of such construction that the ground
`plated that the basic form of such a roadworking appa-
`contact portion 38 extends’in a planar fashion between
`ratus could, with minor modifications, be used for other
`the leading andtrailing ends 40 and 42thereof regard-
`road surfacing operationssuch as, for example, grading.
`less of the contour of the adjacent grade. Thus, the
`In a basic form, the road working machine 10 gener-
`elevation above grade of the rear controlaxis 36 at each
`ally comprises a frame 18; a prime mover, such as a
`diesel powerplant 19; a work piece 20 supported by the
`side of the frame 18 at any selected position relative to
`the roadway14 will be indicative of, or proportionalto,
`frame 18; a drive assembly 21 connected to and support-
`the average of the difference(if any difference exists)
`ing the frame 18; a grade sensor assembly 22A con-
`between the grade elevationsof the leading andtrailing
`nected to the frame 18 and supported adjacent the work
`piece 20 near the left side 23 of the frame 18; another
`ends 40 and 42 of the ground contact portion 38.
`
`25
`
`35
`
`40
`
`45
`
`60
`
`65
`
`4,140,420
`
`FIG.1 is a side elevational view of the grade averag-
`ing apparatus of the present invention in an assembled
`position with a road working machine.
`FIG.2 is a plan view of the grade averaging appara-
`tus and the road working machine shownin FIG.1.
`FIG.3 is a close up view of a portion of the apparatus
`shownin FIG. 1.
`FIG.4 is a close up view ofa portion of the apparatus
`shown in FIG. 1 and taken generally along the line
`4—4.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Page 4 of 10
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`Page 4 of 10
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`4,140,420
`
`10
`
`5
`6
`The grade sensor assembly 22A, shown moreclearly
`for providing a forward elevation reference indicative
`in FIG. 3, is preferably connected to a portion of the
`of the average of the grade ofa selected surface gener-
`frame 18 adjacent the work piece 20 in a selectively
`ally forwardly of the work piece 20; and a connecting
`positionable manner, and is utilized to sense the first
`assembly 60 supported jointly by the rear drive track
`elevation control reference provided by the grade aver-
`assembly 34A and the front sensing assembly 58 for
`aging apparatus 12. In response to sensing thefirst ele-
`providing the first elevation control reference indica-
`vation control reference, the grade sensor assembly 22A
`tive of the average of the forward elevation reference
`provides a first elevation control signal to a portion of
`and the rear elevation reference. The pivotal nature of
`the elevation control assembly 25 indicative of, or pro-
`the left rear drive track assembly 34A about the rear
`portional to, a deviation of the left end of the work
`control axis 36 permits the left rear drive track 34A to
`piece 20 from the first elevation control reference, as
`serve as a track walking beam that providesa rearele-
`will be made more apparent below. The grade sensor
`vation reference indicative of the average grade that
`assembly 22A has a sensor actuating portion which
`supports theleft rear drive track assembly34A.
`specifically senses the first elevation control reference
`The front sensing assembly 58 is defined as compris-
`and, in response thereto, causes the grade sensor assem-
`ing a forward walking beam assembly 62 whichis dis-
`bly 22A to provide the first elevation control signal. In
`posed forwardly of the work piece 20 and extends lon-
`the preferred embodiment, the grade sensor assembly
`gitudinally along the roadway 14. The forward walking
`22A is in the form of a hydraulic sensor 46A having a
`beam assembly 62 includes a beam 66 which is sup-
`sensing wand 48A which generally defines the sensor
`ported above the roadway 14 bya pair of caster wheels
`actuating portion thereof. More particularly,
`in the
`68; and a generally horizontally extending, forward
`preferred embodiment, the sensing wand 48A is pivot-
`control axis 64 is defined as projecting through the
`ally connectedto the hydraulic sensor 46A andcontrols
`midpoint of the beam 66.
`the positioning of a fluid valve (not shown) disposed
`The connecting assembly 60 comprising an averaging
`therein, with the fluid valve controlling fluid flow to a
`bar assembly and includes a connecting bar 70, and
`portion of the elevation control assembly 25, as will be
`wand support assembly 71, and a swing arm 76. The
`made moreclear below.
`a
`swing arm 76 is pivotally connected to the beam 66 at
`The grade sensor assembly 22B, located near the
`the forward control axis 64 and normally extends up-
`opposite side 24 of the frame 18 is similar in construc-
`wardly and toward the roadworking apparatus 10, as
`tion to that described for the grade sensor assembly
`can be seen in FIGS. 1 and 2. The bar 70 is pivotally
`22A, and comprises a corresponding hydraulic sensor
`connectedat its rearward end 72'to the rear drive track
`46B and sensing wand 48B.In like manner to that de-
`assembly 34A near the rear control axis 36 at a point
`scribed for the grade sensor assembly 22A, the grade
`defining the rear elevation reference. At its opposite
`sensor assembly 22B provides a second elevation con-
`forward end 74, the bar 70 is pivotally connected to the
`trol signal via the positioning of a fluid valve that con-
`swing arm 76 at a point defining the forward elevation
`trols fluid flow to a portion of the elevation control
`reference. The rear elevation reference is in a fixed
`assembly 25. As will be discussed morefully below, the
`position in relation to the rear control axis 36 with the
`grade sensor assembly 22B cooperates with other appa-
`bar 70 being pivotal about the rear elevation reference.
`ratus to sense the positioning of a second elevation
`The front elevation reference is fixed relative to the
`control reference.
`:
`front control axis 64 with the beam 66 being pivotal
`The elevation control assembly 25is utilized to vary
`about the swing arm 76 (that is, the front control axis
`the elevation of the frame 18, and consequently of the
`64), and the swing arm 76is pivotal about the bar 70
`work piece 20 in response to the elevation control sig-
`generally at the front elevation reference. The swing
`nals provided via the grade sensor assemblies 22A and
`arm 76 is locked into a selected angular relation to the
`22B. Thus, the elevation and slope of the work piece 20
`bar 70 by a conventional locking means, such asaset
`45
`is determined relative to the first and second elevation
`screw or other bolting means.
`control references. In other words, the work piece 20is
`As shownin FIG.4,a lifting bracket 78 is connected
`selectively positionable in a vertical manner by the
`to the planer housing 30 and forms a slot 79 through
`operation of the elevation control assembly which de-
`which the bar 70 is disposed for limited vertical move-
`termines the elevation of the frame 18. In the preferred
`ment when the grade averaging assembly 12is in use.
`embodiment, the elevation control assembly 25 com-
`As will be discussed more fully below,
`the lifting
`prises hydraulic cylinders 34H and 35H that are con-
`bracket 78 serves to lift the bar 70 so as to position the
`nected respectively between the frame 18 andtheleft
`grade averaging assembly 12 in a grade clearing posi-
`rear drive track assembly 34A and the right rear drive
`tion when the road working machine 10 is being maneu-
`track assembly 34B. The hydraulic cylinders 34H, 35H,
`vered into cutting position.
`shownin broken line detail in FIGS. 1 and 2, serve to
`The bar 70 may be constructed of several pieces of
`position the frame 18 vertically relative to the support-
`bar stock, or the like, welded together to form an inte-
`ing rear drive track assemblies 34A and 34B. Also, the
`gral bar which conformsto the general shapeoftheside
`elevation control assembly 25 comprises a hydraulic
`of the road working apparatus 10. In the preferred em-
`cylinder 33H that is connected between the frame 18
`bodiment, the bar 70 is positioned relative to the frame
`and the front drive track assembly 33; the hydraulic
`18, and the beam 66is positioned relative to the bar 70,
`cylinder 33H serves to position the front portion of the
`such that a medial portion of the bar 70 near the work
`frame 18 vertically relative to the front drive assembly
`piece 20 is substantially midway between the rear eleva-
`33. The grade sensor assemblies 22A and 22B are in
`tion reference and the front elevation reference. Of
`fluid communication with the elevation control assem-
`course, this may vary somewhat depending upon the
`bly 25 by valves and conduits that are not shownin the
`position of the beam 66 relative to the bar 70.
`drawings.
`From the above,it should be clear that if the bar 70
`The grade averaging apparatus 12, as described
`extended linearly between the rear elevation reference
`above, generally comprises a front sensing assembly 58
`and the front elevation reference in a parallel relation
`
`25
`
`35
`
`40
`
`60
`
`65
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`7
`with the roadway 14, the midpoint therebetween, as
`located on the bar 70, would substantially define an
`elevation above grade generally indicative of the aver-
`age of the rear elevation reference and the front eleva-
`tion reference, or in other words, the elevation control
`reference. However, in a more practical situation, since
`the bar 70 is constructed to conform to the shape of the
`road working apparatus 10, and because of the pivotal
`characteristic of the swing arm 76, the actual midpoint
`between the rear and front elevation references, as lo-
`cated on the bar 70, would not accurately define the
`elevation control reference. Thus, in the preferred em-
`bodiment, the wand support assembly 71 is utilized to
`indicate the elevation control reference which is the
`average of the rear elevation reference and the front
`elevation reference. Thatis, the wand support assembly
`71 provides contact meansfor establishing communica-
`tion between the sensor actuating portion, the sensing
`wand 48A, and the elevation control reference.
`The wand support assembly 71 comprises a: slide
`bracket 82 disposed over a medial portion of the bar 70,
`and a crank arm 84A pivotally connected to the slide
`bracket 82. The slide bracket 82 is selectively position-
`able along the bar 70, and a set screw orthe like is used
`to lock the slide bracketin a fixed location on the bar 70.
`The crank arm 84A is selectively positionable relative
`to the slide bracket 82 and is locked in a selected posi-
`tion by meansofa set screw orthelike.
`Moreparticularly, the crank arm 84A is substantially
`S-shaped, as can be seen in FIG. 4, and extends away
`from theslide bracket 82, providing a reference surface
`86 that extends generally parallel to the roadway 14.
`Since the reference surface 86 is locked in a fixed spatial
`relationship near the midpoint of the bar 70, the refer-
`ence surface 86 is indicative of the position of the eleva-
`tion control reference. In an assembled position of the
`above components, the sensing wand 48Ais biased into
`contact with the reference surface 86 of the crank arm
`84A such that the position of the sensing wand 48A
`relative to the hydraulic sensor 46A is determined by
`the position of the reference surface 86 relative to the
`frame 18. In other words, the sensor actuating portion
`(the sensing wand 48A) senses the elevation control
`reference (the reference surface 86), and in this manner,
`the sensing wand 48A and the wand support assembly
`71 cooperate to form the contact means.
`As mentioned above, the grade sensor assembly 22B
`is located on the opposite side 24 of the frame 18, and
`serves in a similar manner to that described for the
`grade sensor assembly 22A. Thatis, the sensing wand
`48B of the grade sensor assembly 22B serves to sense
`the location of an arm 84B that extends from a conven-
`tional skid assembly 90 that is supported by the planer
`housing 30 along the opposite side 24. Of course, an-
`other grade averaging apparatus constructed in accor-
`dance with the present invention and similar to the
`grade averaging apparatus 12 could be attached to the
`side 24, and if this were done, the wand 48B would be
`actuated by a crank arm similar to the crank arm 84A.
`However,for the purpose ofthis disclosure, a conven-
`tional skid 90 is displayed in FIG. 2, and since the con-
`struction of such skids is known, details need not be
`given herein except to commentthat the skid 90 is con-
`structed to slide along a surface adjacent the opposite
`side 24 as the road working machine 10 movesalong the
`roadway 14.
`It will be recognized that a stringline could be set up
`for sensing by the wand 48B, in which case the wand
`
`Page 6 of 10
`
`4,140,420
`
`8
`48B would be oriented to extend generally normal to
`the side 24. As will be discussed below, the use of a
`stringline is an option that may be desirable fora cutting
`pass close to the edge of a roadway. Another option of
`controlling the elevation of a portion of the frame 18 is
`a conventional slope control that would position one
`portion of the frame 18 at a constant setting relative to
`anotherportion of the frame 18. Since slope controls are
`well known, further discussion need not be provided.
`
`Operation of the Present Invention
`During a typical surfacing operation, such as a sur-
`face planing operation performed by the work piece 20,
`the machine 10 and the work piece 20 are initially
`aligned over the roadway 14 at a designated take-off
`area, with the work piece 20 being disposed generally
`transversely to the roadway 14. The take-off area gener-
`ally defines the starting point of an initial pass to be
`madeover the roadway 14 by the roadworking machine
`10.
`Before the machine 10 begins the initial pass, an ele-
`vation control reference is normally established in order
`to maintain the working depth of the work piece 20 at a
`constant elevation relative to the roadway surface. For
`the initial pass, the elevation control reference along the
`edge of the roadway 14 may be provided in a conven-
`tional mannersuchas bythe useofa stringline along the
`edge, or if there should be a curbing surface orthe like
`adjacent the roadway 14, the skid 90 (or a grade averag-
`ing assembly similar to the grade averaging assembly
`12) may be utilized to provide the second elevation
`control reference for the initial pass. That is, the present
`grade averaging apparatus 12 can be used oneitherside
`of both sides or on the machine 10; or the grade averag-
`ing apparatus 12 can be used on oneside of the machine
`10 while the elevation of the opposite side of the ma-
`chine 10 is controlled by a stringline, by conventional
`skid apparatus, or by a cross-slope control. In the inter-
`est of brevity herein, the present invention will be dis-
`cussed with the machine 10 equipped with the skid 90
`on one side of the machine and with the grade averag-
`ing apparatus 12 on the other side. The assignment of
`the machine 10 for the purposeofthis discussion will be
`to remove the top surface of the roadway 14 to a uni-
`form depth of a determined numberof inches measured
`from the top of the existing grade.
`In this mode of the machine 10, the elevation of the
`frame 18 would be controlled as follows. Thefirst ele-
`vation contro! reference is provided by the grade aver-
`aging apparatus 12, and the grade sensor 22A provides
`the first elevation control signal to portion of the eleva-
`tion control assembly 25 as the sensing wand 48A
`contacts the crank arm 84A of the grade averaging
`apparatus 12 as it moves along the surface adjacent the
`side 23 of the frame 18. The hydraulic cylinder 34H
`connected between the frame 18 andtheleft rear drive
`track 34A is actuated and positioned in response to this
`first elevation control signal.
`Continuing the discussion of this mode of the ma-
`chine 10, the second elevation control reference is pro-
`vided by the skid apparatus 90, and the grade sensor
`22B provides the second elevation control signal to a
`portion of the elevation control assembly 25 as the sens-
`ing wand 48B contacts the arm 84B as the skid 90 moves
`along the surface adjacent the side 24 of the frame. 18.
`The hydraulic cylinder 33H connected between the
`frame 18 and the front drive track 33 is actuated and
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`35
`
`60
`
`65
`
`Page 6 of 10
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`~” :4,140,420_
`
`9
`positioned in response to the second elevation control
`signal.
`L
`In operation, the roadway machine10 is positioned to
`maketheinitial pass. The skid 90 is supported on a curb
`apronorthelike along theedge of the roadway 14, and
`the grade averaging apparatus 12 is supported alongside
`the machine 10 on the existing pavementsurface of the
`roadway 14. While in this position, the elevation ofthe
`frame 18 is altered by manually controlling the hydrau-
`lic cylinders 33H, 34H and 35H (by manual controls not
`shown) to position the work piece 20 in touching
`contact with the top of the roadway 14. Thatis, the axis
`of the work piece 20 will at this point have been placed
`in transverse andparallel relationship to the top surface
`of the roadway14 sincethe slope of the axis of the work
`piece 20 will be the sameas the transverse slope of the
`roadway 14. Oncethis has-been achieved, the rotation
`of the work piece 20 is commenced,the entire frame 18
`is lowered by the required number of inches necessary
`to achieve the specified depth of cut: At this point, the
`machine 10 is advanced until the rear drive track assem-
`blies are positioned on the finish grade 16, and the hy-
`draulic cylinder 35H is locked in a fixed position to lock
`the rear drive track assembly to grade. This establishes
`the rear portion of the frame 18 on the side 24 ata fixed
`elevation above the newly cut finish. grade 16. The
`elevation control assembly is now set on its automatic
`mode to maintain the specified cutting depth “as con-
`trolled by the grade sensor assemblies 22A and 22B that
`respectively control the elevation of the frame 18 by
`effecting the extension, respectively, of the hydraulic
`cylinders 34H and 33H. At this point, the roadway
`machine 10 is prepared for cutting advancement along
`the roadway 14.
`As the machine 10 moves forward,an irregularity in
`the existing grade, wereit not for the present invention;
`would cause the w