US007828309B2
`
`US 7,828,309 B2
`(10) Patent No.:
`a2) United States Patent
`Berningetal.
`(45) Date of Patent:
`Nov. 9, 2010
`
`
`(54) ROAD-BUILDING MACHINE
`
`75
`(75)
`
`.
`soe
`.
`v1:
`.
`Inventors: Christian Berning, Zilpich (DE);
`Dieter Simons, Buchholz (DE); Markus
`Schafer, Niederkassel (DE)
`
`(73) Assignee: Wirtgen GmbH (DE)
`
`(*) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 390 days.
`
`(21) Appl. No.:
`
`11/885,460
`
`(22) PCT Filed:
`
`Mar. 9, 2006
`
`(86) PCT No::
`
`PCT/EP2006/002151
`
`§ 371 (©),
`(2), (4) Date:
`
`Nov. 13, 2007
`
`(87) PCT Pub. No.: WO2006/094795
`
`PCT Pub. Date: Sep. 14, 2006
`
`(65)
`
`(30)
`
`Prior Publication Data
`
`US 2008/0203684 Al
`
`Aug. 28, 2008
`
`Foreign Application Priority Data
`
`Mar. 10,2005
`
`(DE) ow. 10 2005 011 052
`
`(51)
`
`Int. Cl.
`(2006.01)
`B60G 9/04
`(52) U.S.C ccceecneeeee 280/124.159; 280/6.154
`(58) Field of Classification Search .............. 280/5.506,
`280/5.507, 5.508, 6.155, 124.106, 124.157,
`280/124.158, 124.159, 124.16, 124.161,
`280/6.154
`
`See application file for complete search history.
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`3,895,820 A *
`7/1975 Takahashiet al.
`4,247,126 A
`_—‘L/L981. Claxton et al.
`5,269,556 A
`12/1993 Heyring etal.
`6,669,216 BL* 12/2003 Elser et al. sss. 280/124.106
`7,055,832 B2*
`6/2006 Germain ............0.... 280/5.508
`
`........ 280/6.158
`
`FOREIGN PATENT DOCUMENTS
`
`AT
`DE
`DE
`EP
`FR
`JP
`WO
`
`272 115
`19 63 704
`28 44 413
`0940274
`2161017 A
`2005-053 377
`WO 97/42377 A
`
`6/1969
`7/1967
`4/1980
`9/1999
`TN9T3
`3/2005
`11/1997
`
`* cited by examiner
`
`Primary Examiner—Paul N Dickson
`Assistant Examiner—Robert A Coker
`
`(74) Attorney, Agent, or Firm—Waddey & Patterson, P.C.;
`Lucian Wayne Beavers
`
`(57)
`
`ABSTRACT
`
`The invention relates to a road-building machine whoseleft
`front wheel (4) or caterpillar, right front wheel (6) or cater-
`pillar, left rear wheel (8) or caterpillar and right rear wheel
`(10)or caterpillar are connected to the road-building machine
`chassis by means of an actuating element and are height-
`adjustable with respect to the road-building machine frame.
`According to said invention, different actuating elements are
`rigidly connected to the road-building machine chassis and
`forcedly coupled to each other in such a waythatthe left front
`wheel (4) or caterpillar and the right rear wheel (10) or cat-
`erpillar are height-adjustable in the same direction and with
`respectto the right front wheel (6) or caterpillar and the left
`rear wheel (8) or caterpillar are adjustable in the opposite
`directions. The all wheels (4, 6, 8, 10) or caterpillars are
`equally height-adjustable. The
`inventive
`road-building
`machine provides a high operationalstability, the improved
`compensation of the adjustmentof lateral hindrance inclina-
`tion of the road-building machine andtheirregularities in the
`longitudinal direction thereof.
`
`2,926,023 A *
`
`2/1960 Kraus oe 280/124.106
`
`37 Claims, 9 Drawing Sheets
`
`
`
`Page 1 of 20
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`CATERPILLAR EXHIBIT 1058
`
`CATERPILLAR EXHIBIT 1058
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`Page 1 of 20
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`

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`U.S. Patent
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`Nov. 9, 2010
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`Sheet 1 of 9
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`US 7,828,309 B2
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`U.S. Patent
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`Nov. 9, 2010
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`Sheet 2 of 9
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`US 7,828,309 B2
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`Page 3 of 20
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`U.S. Patent
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`Nov.9, 2010
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`Sheet 3 of 9
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`US 7,828,309 B2
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`Je dina5
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`Page 4 of 20
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`U.S. Patent
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`Nov.9, 2010
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`Sheet 4 of 9
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`US 7,828,309 B2
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`Pr
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`LN
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`Page 5 of 20
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`Page 5 of 20
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`

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`U.S. Patent
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`Page 6 of 20
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`Nov. 9, 2010
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`Sheet 5 of 9
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`US 7,828,309 B2
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`penisiil,Ny
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`Page 6 of 20
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`U.S. Patent
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`Nov. 9, 2010
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`Sheet 6 of 9
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`US 7,828,309 B2
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`Hoy. Go.
`
`Track
`Wheel base
`Milling width
`
`1700 mm
`6200 mm.
`§=2000 mm
`
`.Area ratio cylinderfront-rear
`
`" Threefold floatingaxie~—st—=<CS
`
`‘1.61
`
`front rear|front roller|rollerfront rear rear left right machine
`
`
`
`
`
`
`
`
`
`
`
`left right|right left|center|center|center|center|center left right
`
`Unevenness
`|Overaitheighi]80]180|80|a0|700;0|0|100;80|-0|100,
`Cylinder} 50|-50|50|50|UETC
`
`iTransverse{%] —--5.88
`
`
`iLongitudinal(%]
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` ae
`vey)
`ve ny
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`qi (
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`
`
`
`front
`
`left
`
`rear
`
`Page 7 of 20
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`Page 7 of 20
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`U.S. Patent
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`Nov. 9, 2010
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`Sheet 7 of 9
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`US 7,828,309 B2
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`Ha. ok
`
`Track
`Wheelbase
`Milling width
`
`1700 mm
`6206 mm
`2000 mm
`
`
`
`
`
`
`
`
`
`front front|rear rear|front right|machine roller|rollerrear left
`
`
`
`
`
`"Floating ‘axle rear
`
`
`
`
`
`=a|Eoapdaeeeeanaa
`|__Unevenness}0|Paesosoopraetorpiaoat
`Cytinder|_O_fTofeo|-to0|
`
`
`
`
`
`11.76
`Transverse[%}
`61
`Longitudinall%]
`
`
`
`
`front
`
`rear
`
`Page 8 of 20
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`Page 8 of 20
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`U.S. Patent
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`Nov. 9, 2010
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`Sheet 8 of 9
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`US 7,828,309 B2
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`Fg. 6c
`
`Track
`Wheel base
`Milling width
`
`1700 mm
`6200 mm
`2000 mm
`
`Floating axie front
`
`
`
`
`
`front|front.|Tear|rear|front|rear left|right|machine|roller|roller
`
`
`
`left right|Fight left|center|center|center|center [center left right
`
`
`
`|_Unevenness|0|200Oo|oFofot
`
`Overallheight]100[100|ofofico|o7so[so7sof50ft50
`
`
`
`Cyinder {00[-ioo[oOfott
`
`
`
`
`0,00
`Transverse [%]
`1,61
`ongitudinal['%]
`
`
`
`
`
`Page 9 of 20
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`Page 9 of 20
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`U.S. Patent
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`Nov. 9, 2010
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`Sheet 9 of 9
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`US 7,828,309 B2
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`Page 10 of 20
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`US 7,828,309 B2
`
`1
`ROAD-BUILDING MACHINE
`
`RELATED APPLICATIONS
`
`This application is the U.S. National Stage ofInternational
`Application No. PCT/EP2006/002151, filed Mar. 9, 2006,
`published in German, and claimspriority under 35 U.S.C.
`$119 or 365 to German Application No. 10 2005 011052.5,
`filed Mar. 10, 2005.
`Thepresent invention relates to a road-building machine,
`in particular a road-milling machine,a recycler ora stabilizer,
`ofwhichthe left front wheelor caterpillar, right front wheel or
`caterpillar, left rear wheel or caterpillar and right rear wheel
`or caterpillar is adjustable in height by meansofan actuating
`member.
`
`Whena road-building machineofthis type travels over an
`obstacle, for example with only onefront wheel, this one front
`wheelis raised by the amountof the height of the obstacle,
`while the other front wheel remains on the road. The road-
`building machine is consequently set obliquely, with the
`result that the milling roller ofthe road-milling machineor the
`milling/mixing rotor of the recycleror of the stabilizer is also
`set obliquely. This effect has an especially disruptive effect
`particularly whenthe track of the machineis relatively low in
`relation to the wheelbase.
`
`Various machines are known from the prior art which must
`react with a suitable way to unevenness in the ground on
`which these machines move, so that the stability of the
`machinesis notatrisk.
`
`USS. Pat. No. 4,247,126 describes an agricultural machine,
`in which twofront wheels and two rear wheels are provided.
`Each individual wheel can be adjusted in height, a working
`cylinder being provided on each wheel forthis purpose. The
`working cylinders are partially connected to one another by
`corresponding lines, a hydraulic control system being pro-
`vided which is designed suchthat either the front and the rear
`wheel on the left side or the front and the rear wheel on the
`
`right side of the agricultural machine can be raised or low-
`ered. Thus, the machine, when it moves transversely with
`respect to a slope, can be straightened.
`EP 0 836 659 B1 discloses a chassis of a road-building
`machine, said chassis having a frame carried on two front
`wheels and two rear wheels. The front wheels of the known
`
`chassis are suspendedsuch that they can follow changesin the
`transverse inclination of the road topping contradirectionally
`and to the same extent. In order to couple the two front wheels
`in such a way that these move contradirectionally and to the
`same extent, the guides ofthe two front wheels are connected
`to one another via a corresponding mechanical or hydraulic
`coupling device. This arrangement, whichis often used in the
`priorart, is also designated as a floating axle.
`The road-milling machine described in EP 0 940 274 A2
`likewise has two front wheels which are adjustable in height
`contradirectionally and by equal amounts. On accountof the
`positive coupling of the front wheels, the known chassis can
`react to elevations or depressions on oneside ofthe road, in
`that one front wheelis loweredor raised, while the other front
`wheel executes
`a contradirectional movement.
`If,
`for
`example, there is an elevation of height a on oneside, the
`corresponding front wheelis raised in relation to the machine
`by a/2, while the other front wheelis lowered in relation to the
`chassis by a/2. Thus, overall, the machine is raised by only
`a/2, thus improving the handiness ofthe machine andincreas-
`ing its driving comfort.
`In the prior art described above, there is the disadvantage
`thatit is not possible to mount both the front wheels and the
`Page 11 of 20
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`2
`rear wheels floatingly, with positive coupling, in the way
`described, since this would lead to an unstable position ofthe
`machine.
`
`Whenthe machineis traveling along and is moving along
`a straight path, any obstacle in the form of an elevation or
`depression on oneside of the machineis driven over not only
`by the floatingly mountedfront axle, but also by the nonfloat-
`ingly mounted rear axle. In the region of the nonfloatingly
`mounted wheels, the obstacle then actsto its full extent on the
`vehicle frame. This is detrimental to the stability of these
`machines. Moreover, where a road-milling machine is con-
`cerned, the milling result is also impaired.
`The object on which the present invention is based is,
`therefore,
`to improve the stability of the road-building
`machinesinitially mentioned, as compared with the prior art
`mentioned.
`
`Furthermore, the object on which the present invention is
`based is to improve the compensation both of transverse
`inclinations of the road-building machines initially men-
`tioned, which occur when obstacles are driven over and
`adversely influence the milling pattern ofthese road-building
`machines, and of unevenness in the longitudinal direction of
`these road-building machines.
`This object is achieved, according to the invention, by
`meansof the features specified in patent claim 1. Advanta-
`geous embodimentsof the invention are the subject matter of
`the subclaims.
`
`The road-building machine according to the invention has
`a left front wheel or caterpillar, a right front wheel or cater-
`pillar, a left rear wheel or caterpillar and a right rear wheel or
`caterpillar. When a front wheel is referred to hereinafter, this
`is also understood to mean a caterpillar. Each of said wheels
`is assigned in each case an actuating member, with the aid of
`which the respective wheel is connected to the chassis of the
`road-building machine and can be adjusted in height in rela-
`tion to the frameor chassis of the road-building machine. The
`frame can thereby be adjusted in height andorientedin rela-
`tion to the ground.In this context, a height adjustment of the
`wheels is simply referred to hereafter. According to the inven-
`tion, the actuating membersare connectedrigidlyto the chas-
`sis ofthe road-building machine andare positively coupled to
`one another. The positive coupling is in this case designed
`such that the left front wheel and the right rear wheel are
`adjusted in height in the opposite direction to the right front
`wheelandtheleft rear wheel, the left front wheel and the right
`rear wheel being adjusted in height in the samedirection.
`The road-building machine accordingto the inventionis to
`be understood as meaning,
`in particular, a road-milling
`machine, a recycler ora stabilizer. Road-building machines of
`this type are knownto a personskilled in the art, and therefore
`a general description of these road-building machines in
`termsoftheir construction and functioning is dispensed with
`hereafter.
`
`If all the actuating members are designed identically, for
`example if cylinders having identical cross sections are pro-
`vided as actuating members, the height adjustment takes
`place essentially by equal amounts onall the wheels. This is
`to be understood as meaning that the amounts may only
`theoretically be exactly equal, that is to say on the precondi-
`tion that, for example, the machine frameis infinitely rigid,
`the contact area is totally inflexible andthe oil is fully incom-
`pressible. In practice, however, minor deviations cannot be
`avoided. It is also possible, however, to design the actuating
`membersdifferently, for example to provide cylinders having
`different diameters, with the result that the tilting behavior of
`the machine can be influenced correspondingly.
`
`Page 11 of 20
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`

`

`US 7,828,309 B2
`
`3
`The positive coupling according to the invention ensures
`that the road-building machine according to the invention has
`high stability, this being particularly important in a road-
`building machine having a narrow track. On account of the
`required transport dimensions, the track is generally rela-
`tively narrow. The road-building machine according to the
`invention puts into practice virtually a floating mount of both
`the front axle and the rear axle, with the result that stability is
`decisively improved. The building machine is therefore
`capable of driving safely over surfaces with a relatively high
`inclination, without the risk of the machine overturning. Fur-
`thermore, the permissible height of an obstacle which can be
`driven over by only one wheel of the machine is doubled, as
`compared with thepriorart. In this case, a permissible height
`ofan obstacle is to be understood as meaning the height which
`can be compensated by the raising or lowering of all the
`wheels of the building machine just such that all the wheels
`stand on the road, without, in the case ofone ofthe wheels, the
`point being reached at which the wheel has completely run
`out or run in, that is to say the machineis “blocked”.
`In the road-building machine according to the invention,
`the actuating members are designed as double-acting work-
`ing cylinders with a first and a second working chamber
`whichare filled with a pressure medium, the working cylin-
`ders being connected to one another by coupling lines. A
`pressure medium which maybe consideredis, for example, a
`hydraulic oil.
`According to an advantageous embodiment of the road-
`building machine according to the invention, the working
`cylinders are arranged in such a waythatthe filling ofthefirst
`working chamber or the emptying of the second working
`chambercauses a lowering of the wheel, while thefilling of
`the second working chamber or the emptying of the first
`working chambercausesa raising of the wheelin relation to
`the frame.
`
`20
`
`35
`
`4
`third working cylinder is connected to the first working cham-
`berofthe first working cylinder via coupling lines.
`Ina further advantageous embodimentofthe road-building
`machine according to the invention, the first and the second
`working cylinder are connected to one another via a first
`coupling line, the second and the fourth working cylinder are
`connected to one another via a second coupling line, the
`fourth and the third working cylinder are connected to one
`another via a third coupling line and the third and thefirst
`working cylinder are connected to one another via a fourth
`coupling line.
`In a particularly preferred embodimentofthe road-build-
`ing machine accordingto the invention, the working cylinders
`form, together with the couplinglines, a closed system. This,
`however, does not rule out the possibility of other hydraulic
`components being connected in another operating mode of
`the chassis.
`
`In a particularly preferred embodimentofthe road-build-
`ing machine according to the invention, therefore, the cou-
`pling lines can be connected to a pressure medium source
`and/or a pressure medium sumpvia workinglines with the aid
`of a valve control, if appropriate with the positive coupling
`being briefly canceled. As a result, further settings on the front
`or rear wheels can be carried out independently ofthe positive
`coupling according to the invention, thus making it possible
`to use the chassis on terrains of the most diverse possible
`form.It is therefore possible, for example, to orient the road-
`building machine according to the invention horizontally,
`even thoughit is standing on ground with a transverse incli-
`nation, in order at the sametimeto level out this ground by
`machining.
`A pressure medium source may be understood as meaning,
`for example, an oil pump, in which case the pressure medium
`sump may be formed by discharged oil within a collecting
`container.
`
`In a further preferred embodiment of the road-building
`machine accordingto the invention,a first working cylinderis
`Ina further advantageous embodimentofthe road-building
`provided for the height adjustmentof theleft front wheel, a
`machine according to the invention,
`the valve control is
`second working cylinder is provided for the height adjust-
`designed suchthatall the wheels are raised inafirst operating
`40
`ment of the right front wheel, a third working cylinder is
`mode and are lowered in a second operating mode,this taking
`provided for the height adjustmentofthe left rear wheel and
`place in each case by the same amount.
`a fourth working cylinder is provided for the height adjust-
`In a further particularly advantageous embodimentof the
`mentofthe right rear wheel.
`road-building machine according to the invention, the valve
`In order to afford particularly simple positive coupling
`control is designed such that each individual wheel can be
`accordingto the invention,in a particularly preferred embodi-
`raised in a first operating mode ofthe valve control and can be
`ment ofthe road-building machine accordingto the invention
`lowered in a second operating modeofthe valve control.
`the first working chamber of the first working cylinder is
`In a modification of the abovementioned embodiment of
`connectedto thefirst working chamberofthe second working
`cylinder, the second working chamberof the second working
`cylinder is connected to the second working chamberof the
`fourth working cylinder, the first working chamber of the
`fourth working cylinder is connected to the first working
`chamberofthe third working cylinder and the second work-
`ing chamberofthe third working cylinder is connected to the
`second working chamber of the first working cylinder via
`coupling lines.
`However, since the positive coupling can also be imple-
`mented by connecting the other working chambers in each
`case, in a further advantageous embodiment of the road-
`building machine accordingto the invention the second work-
`ing chamberofthe first working cylinder is connected to the
`second working chamberof the second working cylinder, the
`first working chamberof the second working cylinderis con-
`nected to the first working chamber of the fourth working
`cylinder, the second working chamberof the fourth working
`cylinder is connected to the second working chamberof the
`third working cylinder and the first working chamber of the
`Page 12 of 20
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`45
`
`the road-building machine according to the invention, only
`one of the two front wheels is raised in a first operating mode
`and is lowered in a second operating mode. This meansthat
`the capability for the individual setting ofthe wheelsrelates to
`only the two front wheels.
`According to a further advantageous embodimentof the
`road-building machine according to the invention, the valve
`control is designed such that, in a specific operating mode of
`the valve control, the left and the right front wheel or theleft
`and the right rear wheel or the left rear wheel and front wheel
`or the right rear wheel and front wheel are adjusted in height
`in the same direction and by the same amount.
`In a particularly advantageous embodiment of the road-
`building machine accordingto the invention,the valve control
`can be operated in an operating mode restoring the positive
`coupling. In this embodiment, this ensures that the user can
`also cancel the positive coupling, in order to carry out addi-
`tional settings on the individual wheels, before he changes to
`the positive coupling mode again.
`
`Page 12 of 20
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`

`

`US 7,828,309 B2
`
`10
`
`6
`5
`hydraulic oil. What is applicable to all the working cylinders
`The invention is explained in more detail below by means
`12, 14, 16, 18 is that a filling ofthefirst working chamber 20,
`of exemplary embodiments, with reference to the accompa-
`22, 24, 26 or an emptying of the second working chamber28,
`nying figures in which:
`30, 32, 34 causes a lowering of the associated wheel4, 6, 8,
`FIG. 1 showsa diagrammatic illustration of a first embodi-
`10, while the filling of the second working chamber28, 30,
`ment ofthe road-building machine accordingto the invention,
`32, 34 or the emptyingofthe first working chamber 20, 22,
`FIG. 2 shows a diagrammatic illustration of a second
`24, 26 causesa raising of the wheel4, 6, 8, 10.
`embodiment of the road-building machine according to the
`invention,
`The working cylinders 12, 14, 16, 18 are connected to one
`another via coupling lines. Thus, the first and the second
`FIG. 3 shows a diagrammaticillustration ofa third embodi-
`working cylinder 12 and 14 are connected to one another via
`ment ofthe road-building machine accordingto the invention,
`a first coupling line 36, the second and the fourth working
`FIG. 4 shows a diagrammatic illustration of a fourth
`cylinder 14 and 18 are connected to one another via a second
`embodiment of the road-building machine according to the
`invention,
`coupling line 38, the fourth and the third working cylinder 18
`
`FIG. 5 showsa diagrammaticillustration ofafifth embodi- and 16 are connected to one anothervia a third coupling line
`15
`ment ofthe road-building machine accordingto the invention,
`40 andthe third and the first working cylinder 16 and 12 are
`FIGS. 6a, 66, 6c show the driving behavior of the road-
`connected to one anothervia a fourth coupling line 42.
`building machine according to the invention in comparison
`Thefirst coupling line 36 connectsthefirst working cham-
`with the prior art, and
`ber 20 of the first working cylinder 12 to the first working
`
`FIG.7showsa diagrammaticillustration ofthe road-build- chamber 22 of the second working cylinder 14. The second
`20
`ing machine according to the invention to make clear its
`coupling line 38 connects the second working chamber30 of
`stability.
`the second working cylinder 14 to the second working cham-
`FIG. 1 showsa first embodiment of the road-building
`ber 34 of the fourth working cylinder 18. The third coupling
`machine according to the invention which,in the form of the
`line 40 connects the first working chamber 26 of the fourth
`road-milling machine mentionedinitially, has a milling roller
`working cylinder 18 to the first working chamber 24 of the
`W (FIG.7) which is arranged between the front and the rear
`third working cylinder 16. The fourth coupling line 42 con-
`wheels of said machine. By contrast,
`the road-building
`nects the second working chamber 32 of the third working
`machine according to the invention, in the form ofthe recy-
`cylinder 16 to the second working chamber 28 ofthe first
`cler or stabilizer mentioned initially, has a milling/mixing
`working cylinder 12. The working cylinders 12, 14, 16, 18
`rotor W (FIG. 7) which is arranged betweenthe front and the
`form, together with the coupling lines 36, 38, 40, 42, a closed
`system.
`rear wheels of the road-building machine.
`Amilling roller ofthis type or a milling/mixingrotor ofthis
`The functioning ofthe road-building machine according to
`the invention from FIG.1 is described below. Whenthe road-
`type is known as such to a person skilled in the art, and
`therefore an exact description of the milling roller or of the
`building machine according to the invention drives, for
`milling/mixing rotor is dispensed with this at this juncture.
`example with the left front wheel 4 of the chassis 2, over an
`The road-building machine according to the invention has
`obstacle of, for example, a height of 400 mm,the piston in the
`a left front wheel 4, a right front wheel 6, a left rear wheel 8
`first working cylinder 12 is retracted by 100 mm on account of
`and a right rear wheel 10 which are merely indicated in FIG.
`the weight of the vehicle. The pressure medium is thus
`1. The wheels 4, 6, 8, 10 allow a movementof the chassis in
`pressed out of the first working chamber 20 ofthefirst work-
`the driving direction which is indicated in FIG. 1 by the arrow
`ing cylinder 12 via the first coupling line 36 into the first
`12. Each wheel 4, 6, 8, 10 is assigned an actuating member
`working chamber 22 of the second working cylinder 14. In
`whichallowsthe height adjustmentofthe respective wheel4,
`this case, the pressure medium is pressed out of the second
`6, 8, 10. The illustration of the connection between the actu-
`working chamber 32 of the third working cylinder 16 via the
`ating member and the individual wheel has been dispensed
`fourth coupling line 42 into the second working chamber 28
`with for the sake of clarity. Here, for example, a guide device
`of the first working cylinder 12. On accountof the positive
`maybe provided whichis connected to the actuating member
`coupling, the pistons in the second and the third working
`and on the end of which the corresponding wheel4, 6, 8, 10 is
`cylinder 14, 16 are moved in the opposite direction to the
`suspendedvia a bracket.
`piston of the first working cylinder 12 and by the same
`In the embodimentillustrated, the actuating members are
`amount, that is to say 100 mm.Since the second andthe third
`designed as working cylinders, all the working cylinders
`working cylinder 14, 16, in turn, are connected to the fourth
`being identical in terms oftheir construction and their dimen-
`working cylinder 18 via the second andthe third couplingline
`sions in the exemplary embodiment. Thus,the left front wheel
`38, 40 in the way described above, this has the effect that the
`4 is assigned a first working cylinder 12, the right front wheel
`pistonin the fourth working cylinder 18 is moved in the same
`6 is assigned a second working cylinder 14, the left rear wheel
`direction and by the same amount as the piston ofthefirst
`8 is assigned a third working cylinder 16 andthe right rear
`working cylinder 12. Thus, the left front wheel 4 andthe right
`wheelis assigned a fourth working cylinder 18. However, an
`rear wheel 10 are adjusted in height in the opposite direction
`arrangement of working cylinders of different piston diam-
`to the right front wheel 6 and the left rear wheel 8, the left
`eters is also possible. The characteristic of the road-building
`front wheel 4 and the right rear wheel 10 being adjusted in
`machine can be influenced by different cylinders being
`height in the samedirection, and the height adjustment taking
`arranged on the front axle andthe rear axle.
`place by equal amounts onall the wheels 4, 6, 8, 10. It may be
`The working cylinders 12, 14, 16, 18 are designed as
`noted that the pistons of the cylinders are moved by only 100
`double-acting working cylinders, so that the working cylin-
`mm, while the height of the obstacle is 400 mm, with the
`ders 12, 14, 16, 18 have in each case a piston-side first work-
`result that the driving comfort andstability are improved. In
`ing chamber 20, 22, 24, 26 and a piston rod-side second
`this case, the overall level of the road-building machineis
`working chamber 28, 30, 32, 34, which are separated from
`raised by 100 mm in this exemplary embodiment.
`one another by pistons located in the cylinder. Thefirst and
`Further embodiments of the road-building machine
`the second working chambers 20, 22, 24, 26, 28, 30, 32,34 are
`accordingto the invention are described below with reference
`to FIGS. 2 to 4 and all have the same basic structure and
`filled with a pressure medium which in the present case is a
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`US 7,828,309 B2
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`immediate vicinity of the respective working cylinder 12, 14,
`functioning as were described with reference to FIG. 1, and
`16, 18, into the corresponding coupling line 36, 38, 40, 42. In
`therefore identicalparts are given the same reference symbols
`contrast to the second embodiment,here, in each case a direc-
`and the above description applies correspondingly. For this
`tional valve 70, 72, 74, 76 which corresponds to the third
`reason, only the additional features of the further embodi-
`ments are dealt with below.
`directional valve 60 of the second embodimentis provided in
`In the second embodiment shown in FIG.2, the first cou-
`the connecting lines 62, 64, 66, 68 in a way in which it is
`assigned to the respective working cylinder 12, 14, 16, 18.
`pling line 36 is connected to the third coupling line 40 via a
`Thus, the individual working cylinders 12, 14, 16, 18 can be
`first connecting line 44. Furthermore, the second coupling
`actuated in such a waythat individual wheels 4, 6, 8, 10 can
`line 38 is connectedto the fourth coupling line 42 via a second
`independently of one another be raised in a first operating
`connecting line 46. Moreover, a first working line 48 is pro-
`mode of the valve control and be lowered in a second oper-
`vided, which is connectedto thefirst connecting line 44, and
`ating mode.
`a second working line 50 is provided, which is connected to
`Asafunction ofthe activation of the individualdirectional
`the second connecting line 46. Thefirst and the second work-
`ing line 48, 50 issue into a pressure medium sump, a pressure
`valves 70, 72, 74, 76, oil is supplied to the piston rod-side
`medium source 54in the form of an oil pumpbeing provided,
`working chamberor piston-side working chamberofthecyl-
`furthermore,in the first working line 48.
`inder 12, 14, 16, 18 assigned in each case to the directional
`The second embodimenthas, furthermore, a valve control
`valve and is correspondingly discharged from the otherside,
`which comprises a first directional valve 56 in thefirst con-
`so that the piston is retracted or extended, with the result that
`necting line 44, a second directional valve 58 in the second
`the building machine is raised or lowered at the respective
`connecting line 46 and a third directional valve 60 in the
`corner. In this case, the pressurizedoil always followsthe path
`working lines 48, 50. When the third directional valve 60 is
`of least resistance. Even if part of the oil were to follow the
`brought into the position a, while the first and the second
`path via all the other cylinders, instead of via the cylinder
`directional valve 56, 58 are opened, pressure medium flows
`whichis assignedto the activated directional valve, the effects
`from the pressure medium source 54 via the corresponding
`on the other cylinders are minor. This is because the pistons of
`lines into the second working chamber28, 30, 32, 34 of the
`the directly adjacent cylinders move in the samedirection by
`working cylinders 12, 14, 16, 18. In reaction, the pressure
`the corresponding amount, while the piston of the diagonally
`medium is pressed outofthe first working chamber20, 22, 24,
`opposite cylinder movesin the opposite direction exactly by
`26 of the working cylinders 12, 14, 16, 18 and is discharged
`this proportionate amount.If the piston of the cylinder 12 at
`via the corresponding lines into the pressure medium sump
`front left is to be raised, for example, by 200 mm, and assum-
`52.
`In this first operating mode,
`the positive coupling
`ing that 10% ofthe oil quantity required for this purpose flows
`described above is consequently canceled briefly, and the
`into the cylinder 14 at frontright, the piston ofthe cylinder 12
`wheels 4, 6, 8, 10 are raised by equal amounts. In a second
`at frontleft is thereby retracted only by 180 mm,instead ofby
`operating mode,
`in which the third directional valve 60
`the expected 200 mm,the piston at front right and the piston
`assumesthe position B, while the first and the second direc-
`at rear left are likewise retracted by 20 mm andthe piston at
`tional valve 56, 58 are opened, conversely, a lowering of the
`rear right is extended by 20 mm. Consequently,the left corner
`wheels 4, 6, 8, 10 by equal amounts takes place. As a result of
`of the building machine is not lowered by the expected 200
`the closing of the first, the second and the third directional
`mm, but only by 180 mm. Moreover, however, the “miscon-
`valve 56, 58, 60, as illustrated in FIG.2, the valve control can
`ducted” oil causes a reverse movement in the diagonally
`be broughtagain into an operating modein whichthe positive
`opposite corner,thatis to say “only 180 mm”’,at frontleft, but,
`coupling described aboveis restored.
`instead, 20 mm in the opposite direction at rear right. The
`The directional valves are preferably electromechanically
`operator can then actuate the operating mode until the desired
`actuated valves. The devices required for actuating the valves
`amount, for example 200 mm,is reached.