CA1064077A - Mobile machine frame and suspension - Google Patents

Abstract

NEW CONVERTIBLE SLIPFORMER

ABSTRACT

A construction machine is disclosed having a main frame that is supported by four vertically adjustable sus-pension points from a pair of modified walking beams located on opposite sides of the main frame. Each walking beam has a vertical steering axis at eahc of its ends connected to a bogey-mounted self-propelled ground engagement means in the form of a wheel or endless track. Both walking beams have spaced vertically adjustable suspension means, one of which is attached to the frame and the other of which is pivoted on a horizontal axis from the frame to constitute a four point suspension. The ground engagement means are steerable in pairs, in unison or independently and can be turned about their steering axes to provide for travel in a plurality of directions. Also 360° steering is included and the frame can be made of two U-shaped members that telescopingly engage each other, allowing the power of the tractors to be used to extend and retract the frame. Tools can be side-or straddle-mounted.

Description

BACKGROUND OF THE INVENTION

The prior art discloses a numher of construction machines having either four points of suspension for a flexible frame on ~our endless tracks, one at each corner;
or three points of suspension on a pair of endless tracks, one on each side of `the machine having a rigid frame. Not-able among these are the machines disclosed in the follow-ing U. S. patents: EARLY 2,844,882, July 29, 1958;
; GUNTERT 2,864,452, December 16, 1958; KNOX 2,202,009, May 24, 1940; STEVENS 2,128,273, August 30, 1938 and ALLEN

2,128,889, September 61 1938 along with CURLETT et al

3,230,846, January 25, 1966; CURLETT 3,249,026, May 3, 1966; SWISHER et al 3,423,859, January 28, 1969 and SNOW
et al 3,540,360 November 17, 1970. The two track machines steer by crabbing, a function which causes the machine to steer in an uneven wobbly path that has a serious effect on the control of the grade, slope and direction of the tool. The machine of MILLER et al U. S. Patent 3,606,827, September 21, 1971 (by the instan-t inventors) overcomes this and other defects by using four tracks, one at each corner, two of which on one side carry the rigid frame at a pivot point central of a walking beam~ The opposite . , front pair and the opposite rear pair of tracks are tied together by linkages so that as to be steerable in pairs, i.e., like the front wheels of an automobile. SWISHER
et al provide a similar steering arrangement operating from a guide line on each side of the machine. The SWIS~ER et al machine has a flexible frame and can be raised to position the frame .: .. ,;~..
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~ of whicll on ollc ~i~c carry the ri~i(l rr.unc at a ~)ivot ~Oillt ccntral of a walk:ing beam. 111e ol~posite front l)air ~uld thc o~)l)osite rcar pair of tracks arc tic~ t~gc~lcr by linkagcs so that ~s to be steerable in pairs, i.e., like the front wheels of an automobile. SWISIER et al pro-vide a similar steering arrangement operating from a guide line on each 6~side of the machine. The SWlS}ER et al~machine has a flexible frame and can be raised to position the frame over a truck and the track support members are pivoted upwardly off the gro~ld for movement by the truck to a new location. For longer hauls, the four track support nembers are removed and transported on a separate truck.

Road construction machines, such as that disclosed in SWIS}IER
et al 3,423,859 are designed to span the width of one or more lanes of a highway for which purpose sizeable flexible frames and/or elongated track support beams are required. Uhderstandably some provisions m~st be made for reducing the overall size of the machine for tr~sport from one work location to the other, even to the extent of actually disconnecting the tracks from the frame. Finite adjustment of slope and gr~de are best provided in machines having a rigid frame.
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; SUMMARY OF I~E INVENTION:
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In accordance with ~his invention provision is made to preserve the advantages of a three-point or four-point suspension in a four track ri~id frame machine while at the same time providing flexibility as to the size and location of the tool, without the necessity of providing outriggers for the tracks or di~m~ntling parts for transport and still further providing a machine that can be moved along an axis which extends full circle from the frame. Not only can ~he four tracks be turned 90 or ~ore in ei~her direction to make the machi~e operc~ble along two dif-~erent a~es pe~pendicular to the frame to allow attac~ument of the tool on ~ny of ~he our sides or in a straddle position, the frame can be moved ~long with all four tracks at any desired angle to the frame and the power ~ -3-: .

-of one pair of tracks can be used to extend or retract the frame - as desired along its telescoping positions.
These multiple functions are made possible by suspend-ing the working tool from a frame that -telescopes along an axis transverse to the normal direction of travel along the grade or lane of a roadway being worked upon and supporting the frame from a pair of longitudinally spaced suspension points at one side upon a walking beam through a pair of pivotal saddles.
This walking beam has a track member at each end. The other .~ 10 side of the frame is supported by a similar dually suspended `; second walking beam or by a single suspension means upon the midpoint of the second walking beam which like~wise has a track member at each end. Each track member i5 rotatably mounted on :~ a vertical steering axis at the end of its respective beam.
Pro~ision is made for full transport operation of the machine along with the raising and lowering functions through the sus-.~ pension points so that the machine can be moved into a straddling position over a tool such as a slip form and lowered thereover for attachment of the tool.
. 20 The frame is adapted to be telescoped along an axis , perpendicular to the walking beams for the compactness required for transport or curb and gutter work or to extend the frame so that it can straddle a wide work area~ Each track is driven by a separate hydraulic dri~e motor associated with and ! carried by the track.
: In accordance with one aspect of this invention there is provided a construction machine comprisingO a main frame;
a first pair of vertically adjustable main frame support means , spaced along one side of said main frame; a first walking ~eam 30 extendin~ alon~ said one side of said main frame an~ pivotally :~

mounted to each of said main frame support means; one of said ,.~

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first pair of main frame sllpport means being pivotally mounted to said main frame on a horizontal axis above and .in s~lbstan-tially the same plane as its respective pivotal mount on said first walking beam; a second pair of vertically adjustable main frame support means spaced along the othler side of said main frame; a second walking beam extending along said other side of said main frame; one of said second pair of main frame support means being pivotally mounted to said main frame on a horizon-tal axis above and in substantially the same plane as its respective pivotal mount on said second walking beam; ground .
engagement means adapted to transport said machine pivotally mounted on m~ans defining individual vertical steering axes at the ends of said walking beams to steer said machine; and said ground engagement means being positionable about said steering axes to transport said machine in a plurality of selected paths extending 360 around-each of said steering axes.
DESCRIP~ION OF THE DRAWINGS:
- FIG. 1 is a partially diagrammatic perspective view of machine devoid of working tools in compact transport condi :, `- 20 tion;
FIG. 2 is a side view of the machine of FIG. 1 with the tractors turned 90 to show the action of the modified walking beam as it pivots on the bogey-mount at one end and the horizontal pivot attaching the suspension tube to the frame at the other end in negotiating an offset in the grade;
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FIG. 3 is ~I cnlar~c~l fr.lg]l~nt(lry v;ew of thc horizontal l)ivot mount for the suspension t~e a~ one end o~ a ~odified walking be~m;

FIG. 4 is a cross-sectional view taken along ~le lines 4-4 of FIG. 3 to show the details of onc -fonn of ~e horizontal pivo~ and the details of one of the telescoping suspension tubes;

FIG. 5 is a fragmentary plan view to sho~ the center- unted walking beam on the other side of the main frame;

FIG. 6 is an enlarged fragmentary view showing one form of means for steering a ground engagement means;

FIG. 7 is a cross-sectional view of a spindle-mount above a bogey-mount for a ground engagement means and a pinion gear assembly for 360 steering.

FIG. 8 is a cross-sectional view of another form o spindle mGunt employLng a solid bearing and a lever-actuated steering means;
: ' FIG. 9 is a fragmentary perspective Yiew of one side of the machine showing the use of one hydraulic cylinder to control the steerlng of a pair of ground engagement means;

FIG. 10 is a fragmentary perspective view of an end nountLng of a walking beam with its associated suspension tube and vertical steering axis or a ground engagement means showing another modi~cation of the steering means.

FX~S. 11, 12, and 13 are ~op plan views of a ground engagement means being turned in sequence through an angle of 90 using the steering m~ans of FIGt. 10.

FIG.l~ shows a further modification of the steering means.
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FIG. 14 is a partially diagr~n~atic perspective view nf the machine of FIG. 1 showing the use of one pair of ground engagen~!nt means :

, to extend or retract tlle fr~le;
~ :IG. 15 is an en1argcd fragmcntary vicw Or a portion of thc telescoping fr~me and gui~e n~ns used therewitll;
FIG. 16 is a cross-sectional view takell along the lines 16-16 of FIG. 15;
FIG. 17 is a cross-sectional view taken along the lines 17-17 of FIG. 15;
FIG. 18 is a perspective view of the machine having a slip form for curb and gutters mounted along one side and a conveyer system for concrete across the front of the machine;
FIG. 19 is a perspective view of the machine with the frame extended and a straddle-mounted tool for laying pavement lanes held between the ground engagement means;
FIG. 20 is a diagramnatic illustration of another emhodiment of the invention wherein a pair of modified walking beams is used in a four-point suspension system, and;
FIG. 21 is a simplified diagrammatic illustration ~f one form of hydraulic steering and suspension control.

DESCRIPTION OF THE PREFERRED EMæODIMENT:
Referring to FIG. 1, the machine 10 of this invention is shown in diagrammatic form to include the frame 12 comprising the side girder : 14 and the opposite side girder 16 tied together by the pair of tubulargirders 18 and 20 to form a rigid, flat rectangular structure. Rigidi-fying cross-members such as shown at 22 and 24 form a support for the :~ prime mover 26 and the non-skid grill 28-to define a working platfoTm.
-- The console 30 is rotatably mounted on the pivot arm 32 which is also . ~
~ pivoted from the socket 34 so that the operator can position the console ~ ' ' , ~ -6-,~ ' : .

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in a numbcr o~ convcnicIlt loca-tioIl~s to coIltrol thc m;lcllincs'oI~er.ltion and also observe th~ work product cu~d ~the I-rogrcss o~ the machiIle.

~ le fr.~mc includcs .ul extcndible U-shapcd frame portion 36 having ~-e outer girder 38 that is about ~e samc siz~ and length as ~le side girder 14 with a pair of smaller box girders, 40 and 42 (see FIG. 14 momentarily) at the ends tha~ extend inside the tubular girders 18 and 20 in a close fitting telescoping rela~ionship. Ihe smaller box girders 40 and 42 can be as long as or longer than the tubular girders 18 and 20 so that the frame 12 can be extended to span a workiIlg area under the frame that is as wide as a single lane of pavement or more. If de sired, means can be incorporated to lock thc frame 12 in selected ex-tended positions or the tool that is attached underneath the frame can be affixed to both the tubular girders 18 and 20 and the box girders 40 and 42 to fix the extended postiion of the frame. The box girders 18 and 20 can each have one or more roller assemblies 44 that have a pair of vertically oriented roller m~mbers 46 opposed to the openings 48 ~n the side walls of the tubular girders 18 and 20 and engage the sides of the smaller box girders 40 and 42 to stabilize the U-shaped frame 36 laterally in its extension and retraction and provide a friction-less support. Also the box girders 18 and 20 can have one or more chain roller assemblies 50 that have a pair of horizontally oriented roller chain members 52 opposed tO suitable openings in the top and bottom walls of the tubular girders 18 and 20 and like-wise engage ~he tops and bottoms of the smaller box girders 40 and 42 to stabilize and provide friction-less support for the extensibl~ U-shaped fr~ne 36. The details of ~he roller assemblies 44 and the chain roller assemblies 50 are shown in FIGS. 15, 16, and 17, to be described.

The fr~me 12 of ~le machine 10 and any working tools carried ~hereby ~re supported in two difEerent maNners in accordance with this invention for finite control of the grade and slope.

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- ~IG. 1 illustratcs onc cn~o~liment whcrein ~e m~line lO is provide~ with a pair of .l~justa~le or cxtcl~al)lc sup~ort mc~ns 60 all(l 62 on one si~e, colm~ctc~ betwecn ~le outer gir~er 38 ~lcl ~Ic n~tliried walking beam 64 by means of ~hc longitudinally spaced sa~dles or bogcy-mo~mts 66 and 68; and the other side of the machine is provided with a single centrally unted adjustable or extelldable support means 70 (see also FIG. 5) connect~d between the side girder 16 and -the center of the walking beam 7Z by means of the saddle or bogey-mount 74 through the pivot pin 76.

Although, as will be described, the mechanical parts of the adjustable support mcans 60 and 62 and 70 are essentially the same, ~ley are identified by different numerals for purposes of clarification in describing their functions wllich differ to cortain extcnts ~n~ are the sane in others.

Rcferring to FIGS:. 1, 3, and 4, ~le adjustable support means 62 will be used to illustrate the parts that are common to the other frame support means. These include the open-bottomed guide sleeve or cylinder 80 which fits over and slides upon the i~ler sleeve 82 which is affixed to the top plate 84 of the bogey-mount 68 by means of the weldnent 86.
The guide sleeve 80 and the inner sleeve 82 are close fitting cylinders adapted to reciprocate in telescoping relationship to provide a linear up and down movement.
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The operating ram 88 is contained within the cylinders 80 and 82 with its housing supported by means of the top central journal 90 pivotally mounted on the clevis pin 92 that extends diametrically across the tc)p of the ~ylLnder 80. The lower end of the ram housing extends within the open top of the inner sleeve 88 and the piston 94 connects to the pisto~ rod 96 ~hat extenc~ through the packing gland 98 to and ~hrough the top plate 84 of the bogey-m~unt 68 where it is afixed by n~ans of the locking flanges lO0 and the loc~ nut 102.

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The ram 88 can be singlc or do~)le-acting, since in the rormer instance the wei~t of the machine c~m ca~sc ~lc rctra~tiorl ol~ thc ram.
e hydraulic l~les 104 an~ 106 ~Icrefore (FIC. 1) are omitted from FIG. 4 for simplicity, one connecting by means o-f a flexible cable to the housing 88 above the piston 94 and the other, when ~sed, connec~ing below the p:iston. The operation of the ram 88 raises and lowers this corner of the frame lZ. The clevis pin 92 permits a slight play in these parts so that the reciprocating sleeves do not bind as they extend and retract, as disclosed in U.S. Patent 3,606,827.

Internally, the extensible support member 60 is the same as the support member 62 just described9 however, the extensible support member 60 is affixed to the girder 38 by means of the bracket or encircling flanges 108 e.g. it is not pivotally unted to the frame. This at-tachment is made permanent by welding.

The adjustable support means 62 is pivotally mounted to the frame 12 on an axis that extends horizontally of this side of the frame (FIG. 3).
For this purpose the pair of support plates 110 is provided that are affixed at one end to the opposite sides of the cylinder 80 and extend inwardly from ~he corner of the frame to provide support for the bearing cap ass0mbly 112 encircling the pivot pin 114 which is affixed to the outermost box beam 38. The pivot pin 114 is of heavy construction and the bearing cap assembly 112 can be of the split ring type whereby a slotted opening therein allows adjustment of ~he contact with the pin to prevent looseness, as by means of the adjusting bolts 115. The support plates are appro~riately slotted as at 116 so that assembly and dis-asse~bly are facilitated, and the lock nut il7 provides lateral or axial adj~stment of this pivotal connection. As the adjustable support means 62 pivots on ~he pin 114 the innermost plate 110 may be in guided relationship against the side of the beam 3B or spaced therefrom as shown at I18.
, The extendable sl~port member 60 is vertically aligned with the fram~ and its sleeve 82 attaches to the bogey-mount 66 directly over the ` , .

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pivot pin 120 which is carried by the en~ of tlle ~alking be~n at the steering housing 122 ~cfining a vertical steering axis for the second bogey-mount 124. Similarily, the adjustable support means 62 is mo~lted over the pivot pin 120 of the bogey-mo~lt 68 forming a pivotal at~ach-ment to the steering housing 122 on the other end of the walking beam 64.
~lerc again the housing 122 defines a vertical steering axis for the as-sociated bogey-mount 124. Sufficient space at 126 (FIG. 4) is provided between the underside of the platcs 84 and the pivot housings 122 of these respec~ive bogey-mounts 66 and 68 so that the walking beam is free to pivot on the pins 120.
Referring to FIGS. 1 and 5 the extensible s~port member 70 on the other side of the frame 12 is vertically affixed to the girder 16 by means of the pair of unting plates 128 and the encircling flanges 130 in a man-ner similar to the extensible member 60. ~lowever, in this instance means are provided to maintain the second walking beam 72 in lonlJitudinal align-ment with the side of the frame 12. This is accomplished 1)y using a pair of ram units 60a and 60b, so designated because they are identical to the unit 60, in side-by-side relationship. Each has an outer guide cylinder 80 and an inner sleeve 82 that reciprocates therein due to the action of the rams ~not shcwn) which in this instance are operated to extend and retract in unison. The inner sleeves 82 are af-fixed to the top plat~ of the single bogey-mount 74, of larger dimensions and the ~ogey-mount is pivoted to the center of the walking beam 72 by means of the transverse pivot pin 76. The two extensible members 60a and 60b constituting ~he single extensible support 70 on the opposite side of the main frame keep the walking beam in align-ment along the side of the frame 12~ The girder 16 has the off-set at 132 (FIG. 1) and the adjustable support means 70 is recessed therein so that this side of the ma~hine is co-planar with the walking beam 72. The ir~er girder 134 ties these parts togcthcr.
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~ f~ 9 Referring back to FI(,S. 1,2 ~d 5 it ls seen tllat both of the walkin~ beams 64 and 72 are positioned parallel to each other and to the sides of the main frame, and also that each is about the same length as its respective frame si~e whereby to place the ends of the walking beams ~Ider and in substantially vertical alignment but spaced belo~ the ~our corners of the frame. ~le extenslble support means 60 and 62 are spaced along the one side of the frame member and the extensible support means 70, being about the midpoint of the opposite si~e of the frame is at a midpoint between the extensible members 60 and 62 to define a three-point suspension between the frame 12 and the walking beams.
A steering spindle is providcd at the ends of cach walking beam.
Thus, as previously described, the walking beam 64 has the steering spindles or housings 122 at its ends while the walking beam 72 has the steering spindles 122a and 122b at its ends, being identically constructed and having the same functions. Each of the tractors 140 has a track frame 142 carrying an endless track 144 and has a drive motor 146 at one end suitably mounted upon the track frame to a drive cog wheel within these tractor units. Each tractor is pivotally attached to a bogey-mount 124 by means of a pivot pin 150 that attaches through a midpoint of its track frame 142.
The steering spindles 122 each have a cylindrical cap member 152 (see FIGS. 3, 6, 7, and 8) in which the spin~le bases 154 are rotatably mounted, with their lower ends affixed to the top plates 156 of the lower bogeys 124 by means of the weldments 158.
In one aspect of the invention each of the.steerin~ spindles 122 includes means to ~otate the lower saddle or bogey 124 and the tractors 140 about their vertical axes at least 90 and preferably about 100 or more, and, if desired, in a complete circle. This ro~ation can be under finite .

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control and accomplishe~ se~uentially, in ~lison or in~ivi~u~lly wi~
the machine in mot-ion or st.u~ding still ~s dcsirc~.
FIGS. 1, 2, 3, 5, ~ld 6 ill~trate onc fo~n of steering control ~d spindle mounting that can be used -for these pu~)oses wherein in FIG. 1 the modified walking beam 64 is shown to include the pair o~ rams 160 and 162 extending in opposite directions along the inside of this support member and having their housings pivotally at~ached to the spaced cleats 164 and 166 that extend from the central portion of the modified walking beam 64. Referring to FIG. 3, the tractor 140 at this co~ner of the frame has been turned 90~ from its position in ~:IG. 1 by means of the ram 162 which now has its operating rod 168 attached to the pivot pin 170 carried by the cleat 172 extending from the inside of the top plate 156 of the bogey-mount 124.
This plate 156 also has a second cleat 176 with a bore hole 1~8 to which the rod 168 and pin 170 were attached when the tractor 140 was in the position shown in FIG. 1. The pivot pins 170 and ]80 at the oppo-site ends of the ram 162 are the quick-release self-locking variety so that the ram 62 can be easily connected to one or more of the cleats se-quentially or removed for servicing. The rams 160 and 162 can be of the long stroke type whereby the tractors 140 can be turned in an arc of about 30 or more, each side of the positions shown in FIG. 1, in a single stroke.
A third cleat 181 is also shown for further use in turning the tractor 14G in this manner.
The hydraulic lines for the ram 160 are illustrated at 182 ~nd 184 and the hydraulic lines for the ram 162 are illustrated at 186 and 188.
The ram 160 connects to the bogey-mount 124 by means of a similar cle 1~9 (FIG. 1) and pivot pin, like the pins 170 and 180. Throughout the construction as many parts are made intercllangeable as possible.

.~ ' ; -12-~ ' ~ ;7~' 1ll cith~r a l)arallcl or t~l~cm l)o~ition ol` tlle ~I`.I~tOr~ Oll .U~y one walking be~m, to accoll~lisll a stecrillg ~ul~tion, tl)c rallls ]~() alld 1(i2 are operated in unison in opposite dircctions, that is tlle r~un 160 contr.lcts as the ram 162 extencls so that the tracks 140 remain parallel like the ~ront wheels of an automobile (FIG. 1) or remain in tanclcm (~ . 3) ass~unillg the other tractor is also turned 90. Ilowever, for otheI purposes these rams may be operated independently and in opposi~e directions, as will be des-cribed for some steering functions or to position the tractors in a t~ndem relationship along the modified walking beam 64.
In FIGS. 1, 5 and 6 the manner of attachmen~ of the second pair of long-stroke rams 190 and 192 on the other side of the frame 12 is shown.
The ram 190 connects between the pivot 194 connected to the housing end on the underside of the walking beam 72 while its operating rod 196 connects to the cleat 198 by means of the quick-release pivot pin 200. Similarly the ram 192 connects between the pivot 202 at the housing end and the cleat 204 and the pivot pin 206 on the bogey-mount 124 at the other end of the beam 72.
The hydraulic lines 208 and 210 control the ram i90 and the hydraulic lines 212 and 214 control the ram 192. The rams 160 and 162, 190 and 192 can be identical and are interchangeable, along with their pivot pins. These rams ma~ be short stroke rams since multiple connections are provided.
' The rams 190 and l9Z are also operated independently, oppositely or in unison and for the purposes described in connection with the rams 160 and 162. Thus steering means for turning the four tractors in unison, in pairs or individually in the same or opposite directions are disclosed.
Other forms of steering control can be used in place of the steer-ing rams just described. As shown in FIG. 7 the steering housing lZ2 a~ the end of each walking beam,for example the walking beam 64~ can be modified to include the conical bearing surfaces 220 at the top and the o ffset opening 222 at the bottom which encompasses the base 154 attached to and , extending from the bogey-mount 124. The base 154 provides a matching conical bearing surface 224 to contain ~o or more tapered roller bearings 226 operating on the radial spindles 228 supported from the vertical spindle 230.
The driven gear 232 is affixed to the top end of the spindle 230 by means of the spline 234 and the hold down bol-t 236. The drive pinion gear 238 en-gages the driven gcar 232 and thc drive motor, thcrefore (not sho~) would be mounted on a non-turning part such as the walking beam 64. A suitable safety housing 240 for this arrangement is illustrated in broken lines in FIG. 7.
In order to tu~n the tractor more than 180 on this vertical steer-ing axis the electrical or hydraulic connections from the power source of the machine to the motor would be disconnected and repositioned to prevent their winding up on the housing 122 or other stationary parts. Quick dis-connect fittings are used for this purpose.
. In another embodiment shown in FIG. 8 the steering housing 122 at the end of the walking beam 64 comprises an open-bottomed cylinder 242 which encompasses the base 154 to form a bearing cap ar:rangement and the spindle 246 extends through the top center of the cylinder 242 where it is splined at 248 to the steering arm 250 and held thereto by means of the nut 252 attaching to the extension 254. The arn 250 has a suitable boss at its extended end having the vertical bore hole 256 to which a steering ram such as 160 or 162 attaches. ~le purpose of the arm 250 is to provide ~: leverage for the steering function and also the means by which the arm can be quickly detached from the spindle 246 and re-set a~ a different angle therefrom ~n the spline 248. Upon re-attachment of the ram thereto its operation will turn the assembly to the next direction chosen for the trac-tor a~ that suspension point. These modified steering arrangements of FIGS~ 7 and 8 can also be used with the walking beam 72.
In FIG. 9 another steering arrangement is disclosed~ in this .~ instance illustrated in relation to the modified walking beam 64 although ~' .

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equally applica~le to the walking beam 72, wherein the pair of bogey-mounts 124 are tied together by the connecting or radius rod 260 by means of the pivot pins 262 and 264 attaching to the respective cleats 266 and 268. The length of the rod 260, which can be adjustable, is such that the tractors 140 are held in paral-lel relationship. The single ram 162 and its operating rod 168 connects between the cleat 166 on the inside of the modified walk-ing beam 64 to the pin 170 and associated cleat 172 as i:Llustrated in FIG. 3. The number of cleats used on each bogey mount can be varied depending on the steering versatility desired in the machine.
FIG. 10 illustrates, in relation to the modified walking beam 64, how ram 162 and its op~rating rod 168 is colmected to the pin 170 carried by the cleat 172 which is oriented a~ about 90 from the cleat 176, and the cleat 181 is 90 from the cleat 176.
FIGS. 11,12, and 13 illustrate how the ram 162, for pur-poses of illustration, is used to re-orient a trac~or 140 from a parallel position, FIG. 11, to a tandem position, FIG. 13, in re-lation to one end o~ walking beam 64. In FIG. 11 the ram is connected to the cleat 172. Retraction of the r~m moves the parts to the position of FIG. 12. The pin 170 is released from the cl~at 172 and the ram extended to the position shown in FIG. 12 - for attachment to the cleat 181. Upon retraction of the ram the ; tractor assumes the tandem position of FIG. 13 at which position the piston in the~ram is at about the center of its stroke.
FIG. 13A illustrates the use of four cleats, with the addi-tional cleats 270 and 272 oriented at 90 from the others.

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This process is repeate~ for the tractors 140 on the cnds of the walking beam 72 and the machine, its frame and tractors assume the posi-tions shown in FIG. 18. It is apparent that the l~aclli.ne 10 can have its narrowest length determined by the box beams 18 and 20. With the tractors 140 oriented as shown in FIG. 1 the machine can be run upon a trailer and be transported to and from work sites. Once the machine has been run off the trailer the tractors 140 can be oriented 90 or to the tandem positions show.n in FIG. 18 and a working ~ool such as the specially designed slip form 280 can be attached by means of iks frame suppor~ members 282 and 284 to spaced bracket mounts 286 on the outer girder 38 with the frame in its retracted position. The slip form 280 has an open rear end 288, from which the extruded concrete curb is deposited upon the prepared grade 290, and a shaped top wall 300 to define the properly contoured type curb-ing to be laid. The tubes 302 in the front wall 304 are provided for the nsertion of reinforcing rods (not shown) by hand as the machine progresses in the direction of the arraw 306. The slip form 280 has, the integral vibra-tion hopper 308 in communication with its interior just behind the wall 304.
The cleat 310 provides pivot suppor~ for the receiving hopper 312 by means of the pin 314 engaging the angle bracXet 315 (see ~IG. 19).
The receiving hopper 312 has an integral chute 316 llousing the helical conveyor 318 driven by a motor withLn the housing 320. 'I'he conveyor 318 extends to the bottom of the receiving hopper 312 so that ready-mix con-crete is picked up and moved to the delivery chute 322 which dumps the concrete into the vibration hopper 308. In the vibration hopper the con-',~
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-1~-cre~e is conpacted by gravi~y .uld vibratioll c~l(l r~d to tlle slip fo~l in a mc~ner known in this art. Ille slip form 280 is ol~en at the bottom along its length. ~le ccntral brac~et 324 carried by ~he beam 18 is U-shaped to conform with the contour of the chute 316 c~ld cc~n be adjustable to provide the necessary elevated support for the conveyor chute.
The slip form 280carries the forward grade sensor 326 i~d the rearward grade sensor 328 having their respective sensing arms 330 and 332 in contact with the under side of the grade reference line 334 sus-pended by the brackets 336 supported by the spaced stakes 338. The pen-dulum operated slope sensor 340 ci~n be located at any position along the center line of the machine extending from the adjustable support means 70, as on the beam 38, so as to be about halfway between the two grade sensors. Suitable adjustable jacks are used to support the sensors 326 and 328 from the tool in a manner well kno~n in this art.
The front steering sensor 342 and the rear steering sensor 344 are located on the slip form at or near the ends of this tool with their pend~nt sensors 346 in contact with the inside of the string line 334.
With a supply of concrete maintained in the hopper 312 from ready mix trucks the machine is capable of laying curb and gutter on the grade 290 to specifications. When the tool is straddle mounted the sensors can be carried on the adjustable bracket 341, shown in Fig. 3, attached to the dified walking beam 64.
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In the event the machine is to be used for pavi.ng one or more lanes of a highway the frame 12 is e~tended to the posltion shown in FIG. 19 to accommodate the concrete spreading and com-pactlng tool 350 which, as is known in the art, includes the screed plate 351 with ~he side frame members 352 and 354 support-ing the elonga~ed helical spreader 356 driven by the motor 358.
The tool 350 is adjustably supported from ~he frame 12 by means o the brackets 360 and has the flat finishing plate 362 ~or leveling and smoothing out the concrete which is dumped or roughly spread on the prepared grade 290 ahead of ~he machine, traveling in the direction of the arrow 306. A pl~rality of pneumatic vibrators 364 are provided as desired. The tool 350 can be attached on the opposite side 20 of the frame, in which event the direction of travel will be cpposite to that of arrow 306.
The attachment o~ either the slip form 280 or the paving tool 350 to the machine 10 is facilitated in that with the tool resting on the ground the machine can be easily maneuvered along-side and lowered on its adjustable supports 60, 62 and 70 for attachment to the connecting support brackets. The machine is then raised to its operating positlon.
FIG. 14 illustrates one manner by which the frame 12 can be extended or retracted, a~ter the machine is run off o its trailer~ In this instance the trac~ors 140 o~ the walking beam 72 have been turned to their tandem position and the tractors 140 on the modLfied walking beam 64 are operated in either direction r 1 8--~; , , (see arrow 365) in unison to pull the U-shaped frame member 36 outwardly or to push the U shaped frame member 36 inwardly into a retracted position. Instead of turning the tractors 140 on the walking beam 82 to the tandem position shown in FIG. 14, these tractors can be locked or lmmobilized to provide the neces-sary braking action for the extensive or retraction of the frame 12.
Alternately, the tractors 140 on the walking beam 64 can per~orm the locking or braklng function and the tractors on the walking beam 72 used to supply the power.
In FIGS. 1, 14, and 19 the U-shaped frame member 36 ls shown as telescoping inside ~he box beams 18 and 20. It is appar-ent that this relationship could be reversed or that the adjustable supports 60 and 62 attached to the cross-beam 16 on the other side of the frame and the central support 70 can be attached to the U-shaped frame member 36 on the opposite side of the frame.
Because of the siæe and weight of the machine, the tele scoping activn of the frame is facilitated by the provision of the roller assemblies 44 to include the spaced paLr of side rollers 46 on one side of the box beam 18 (see FIG~ 15) supported QppOSite the openings 48 by means of the identical support bracket member~
374 that are afixed to the top and bottom of this bea~. The brack~ts have suitable cleats 376 which rotatably support the rollers on their axles 378. The brackets 374 are double-ended (see FIG. 17) and have an opposing palr of rollers 46' on the opposlte side with a similar opening 48' therein allowing the roLlers to ride against the outer sldes of the internal telescoping beams 40 and 42 which are part of the U-shaped ~rame member 36. Any number of such rollers can be u~ed along the sides of the frame.
In addition to the rollers 370 there are providled the roller chain assemblies 50 whlch include the top and bottom roller chains . -19 ~ ~ y~ }~
52 (FIG. 16) that are contained within the housings 382, affixed to the box beams 18 and 20 by means of the brackets 384. ~he roller chains 5~ encompass the divider wall 385 provided in each housing which allows the individual rollers 386 thereof to be pressed down-wardly or upwardly in rolling con-tact against the top and kottom walls 388 of the beams 40 and 42 and also allows the entire chain to travel aro~md the guide walls 385. The openings 390 are provided in the wall 400 of the tubular girders 18 and 20 so that rolling con-tact between the chains and the walls is provided. The roller asse~blies 50 can be suitably lubricated, as desired. By these means both vertical and lateral rolling support for the U-shaped Erame member within the tubular girders facilitates the telescoping action. Actually the beams 40 and 42 are carried within the outer beams 18 and 20 in longitudinally spaced relationship and the only contact is through the rollers 46 and the chains 52.
Normally it is not necessary to lock the frame in any parti-cular extended position since the machine carries the paving tool 350 fmm both portions of the frame by means of the various rigîd supports 360 and the screed 362 is also a rigidlfying connecting m~mber which would prevent further telescoping once it is attached. ~Icwever, :if desired, the external box girders 18 and 20 can be provided with a suitable bore hole 402 to accommodate the drop pin 404 which engages any one of a series of spaced bore holes 406 in the top wall 388 of the internal girders 40 and 42, as shown in FIG. 15. Placemnt of the lock pin 404 into any one of the bore holes 406 as they register with the bore hole 402 will lock the frame in tha-t position.
FIG. 20 illustrates a modification of the general frame and suspension assembly wherein the two opposite sides 36 and 16 of the frame 12 which can be rigid or telescoping, are suppor-ted by the spaced vertical adjustable means 60 and 62, with ~heir transverse or lateral pivots 114, .

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located at opposite corners of the frame, and with -the modified walk mg beams 64 there below supported by the tractors 140. This arrangement is useful with the tractors orien-ted in the positions shcwn in FI~. 20 and the normal directions of travel would be in the directions showr. by the double arrow 414. The arrangement shown in FIG. 20 can also be :Eurther n~xlified by reversing one of the modified walking keams 64 along its respective side 16 or 36 of the frame 12. This would place the transverse or horizontal pivobs 114 on the diagonal in relation -to the corners of the frame.
Although the embodiment shown in FIG. 20 including the aEore-said mcdification does not share all of the versatility and finite grade or slope control of the arrnagement of vertical suspension means and walking beams shcwn in FIG. 1, the machine of FIG. 20 can be used for a large.number of paving and earth working operations. Wherein ad-vantage can be taken of the steering versatility along with the ability to negotiate grade deviations as opposed to slope control.
Furthermore the directions of travel for the machine shown in FIG. 20 whether m~dified to palce the pivots 114 on the diagonal are not to be lim4ted to the ~i-directional arrow 414 and the machine can travel in directions perpendicular thereto as well as at any chosen angular direction in relation to the frame 12.
From the foregoing description it is apparent that the machine o t~is invention is capable of traveling in any of our directions as Lndicated ~Y the arrows 500, 501, 502, and 503 in FIG. 1 in relation to ~he frame and also capable of traveling at any desired angle in relation to the frame. A working tool or tools can ke carried in any position on :, ":

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:

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the four sides or under the frame an~ thcreby be adaptt~d to clo work when carried in any direction. The st difficult position for the tool as far as control ls concerned would be on the side of the frame opposite the walking beam 72 because in this position the tool would be pivoted about its center during grade adjuL~tments or when the machine was ne-gotiating deviations in the grade.

Any of the three or four adjustable sl~ports 60, 62 or 70 can be used to control the attitude of ~he machine 10 in relation to grade or slope. With the machine traveling in ~he direction of arrow 500 of FIG. 1, the suspension means 60 becomes the front grade control and suspensio~ means 62 becomes the rear grade control while the suspension means 70 controls the slope. If the machine is traveling in the direction of the arrow 502 the suspension means 62 becomes the front grade control, the suspension means 60 becomes the rear grade control, and the suspension means 70 controls the slope.

With the machine 10 traveling Ln the directi~l of the arrow ; 501 or the re~erse direction shown by the arrGw 503 the suspension means 60 and 62 become ~he front or-rear grade control means or either of the suspension means 60 or 62 can be used or slope con~rol of the entire machine, when opera~ed independently and the suspension m~ans 70 becom~s the grade control for the front or rear of the ma~hine. It is obvious that with the ~chine traveling in the direction of the arrows 501 or 503 Ln ~IG. 1 that the suspension means 7~ cannot control slope and becomes either a front or rear grade control.
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The unique action of the modiEied walking beam 64 used in conjunction with the walking bec~m 72 accounts for this, as ~shawn in FIG. 2 where the machine is negotiating a deviation 504 in the grade 290. The front or rear tractors are higher or lower, as the case may be, with the machine traveling in the directions of the a~rows 500 or 502. m e central pivot 76 of the central support means 70 on the other side of the frame 12 allosw -that other side to negotiate the deviatian 504 without a change in slope. The pivots 114 and 120. on the other hand plus the action of -the bogey-mounts 124 allaw the machine to be responsive to the grade sensor and a~erage out the devia-tion. A105, a machine having the suspension system oE FIG. 20 can correc~ for such a deviation when traveling in either direction, whether or not the deviation extends acrosss the grade in front of both pairs of tandem tractors.
The ins-tant invention also contemplates the use of a hc~Ling type of sensor and feed back u~it, illustrated ~y the numeral 506 in FIG. 3. The sensor 506 is mounted in a protective recess 508 in the walking beam 64 just ahead of the steering spindle 122 and has its sensor wheel 510 connected by means of the drive belt 512 to -the pulley 514 that rotates with the bogey-m~unt 124 thereunder. One such sensor 506 would be used at each of the steering spindles 122 for the four tractors and a protective hous.ing would be provided for these units.
The sensors 5Q6 are of the hom~ng -type having à pre-set angle, zero o~ null point for the sensor wheel 510 at which no signal is sent to the servc~hydraulic system oontrolling the steering rams 160, 162 and 190 and 192, assum~lg this type of steering is employed. Alternately, .
the sensor 506 can control the drive motors for the pinlon gears 230 ;
~23-~i3~ q~
(FIG. 7) at each corner of tllc machine. ~cn .uly onc track tllms tllc pulley 514 is rotated in relation to the walking beam which moves thc belt 512 and turns the sensor wheel 510 off the null point. ~is sends a sig-nal to the servo-hydraulic system ~nd operates the steering means of the opposite tractor to rotate it the same amount so that the pairs of ~ront and rear tractors steer in unison.
Other modifications of the machine can be made without depart-ing from the invention. A single extensible member ins~ead of the pair of such members 60a and 60b (FIG. 5) can be used provided means are incorporated to maintain ~he walking beam 72 in parallel aligned relationsllip with its side of the frame. Also, the extensible member 70 can be affixed directly to the walking beam 72 through the guide tubes 82 and the transverse pivot pin 76 moved up and located between the frame me~er 16 and the plate 128.
iS places the pivot 176 in the plane of the frame 12 and also in the plane of the horizontal pivot 114 Eor the modified walking beam 64, and may be used to gain further finite cont~ol of slope and grade.
~ The curb and gutter tool 280 shown in FIG. 18 can be replaced by - a screed adapted to form syn~letrical or asymmetrical barrier walls of either linear or curved configuration. Such screeds are well known in the art and include an adjustable sidewall forming the desired shaped configuration and ~oblique surface portion of the barrier wall so that the respective sides of the barrier wall have their corresponding oblique portions at predeter-mined height from the grade or foundation on ea~l side. Also9 adjustable skirts can be used adjacent both sidewalls to facilitate the proper adjust-ment of the screed lower edges in relation to the grade. These adjustable sidewalls are operated manually or automatically from a grade re-ference.
A suitable hydraulic system Lor steering grade and slope control is illustrated in FIG. 21 diagramatically wherein the essential parts of ` the machine are shown, namely ~he pair of beams 64 and 721 with their asso-.-~.. .

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:

ciatcd tractors ~ld thcir resl)cctivc stecrillg r;ul~ ()2, 1~)() ;Ind l~2 along with thc three s~spension poin-ts rcprescnted by thc pair of r~s 60 and 62 on one side of thc fran~ and ~hc sin~lc ecntr.ll r~n 70 on thc othcr side of the frame. Each circuit to a ram includes a check ~alve and one way valve so that the response of the ram is ~lder contlol. Thc source of hydraulic pressure and return is represented by the lines 400 and 402.
It is apparent that the slope control 340 at the top of the dia-gram controls the ram 70 through the solenoid valv~ 404. ~len the desired slope is being maintained as the machine progresses in the direction of the arrow 306, the valve 404 is at position 2 and ram 70 remains stationary.
If the tractors supporting the beam 72 meet a depression and this side of the machine lowers, the slope control 340 will cause the valve 404 to move to position l and oil from line 400 will cause the ram 70 to extend until the frame is again level at which time the slope control shifts the valve 404 back to position 2. If this side of the machine is too high, the slope control 340 shifts the valve 404 to position 3 and the oil p-ressure above the piston is returned to sump via line 406.
, At the bottom of the diagram the front grade sensor 326 takes its signal from the grade line 334 and controls the solenoid valve 408 controlling the front suspension ram 60 at the forward end of the beam 64. The shifting of the valve 408 to position l raises.this corner of the machine, the position 2 of the valve 40~ represents no height change, while the posi$ion number 3 represents the position of the valve where a lowering is called for by the grade sensor 326. Similarly for ~he rear corner of this side of the machine the grade sensor 322 takes its signal from the same grade line 334 and through the solenoid valve 410 causes it to remain static in position 2~ lower in position l and raise in position 3.

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IhC front stecrill~ scnsor ~2 takc~ it~ si~nal rroln tl~c ~ra~eline 334 an~ througll the so1.enoicl valve 412 controls thc pair of rL~s 160 and 190 to turn tllC front tractors lcft in positi.on 1, maintai.n thc course in positi.on 2 and make a right turn in position 3. l~e rear steering sensor 344 controls the steering rams 162 and 192 in the s~me manner through -the solenoid valve 414 so that the tractors 140 on the rear ends of the beams 64 and 72 turn left or right in unison. A right turn by the front pair of rams will bring the rear steeri.ng sensor 344 away from the string line 334 at the rear of the machine and cause, at first, a slight left turn correction by shifting the solenoid va:Lve to position 3, momentarily, to maintain the sensor in contact with the string line, then a gradual right turn by shifting the solenoid valve 414 to posi-tion l. In this way the framc of the machine or the pair of beams 64 and 74.is maintained in a chordal position on the inside of a right turn and in a tangential position on the outside of a left turn.
When the front tractor on the beam 64 negotiat:es a ~lange in the elevation of the grade, the change in the attitude of the frame in rela-tion to the grade line contacted by the sensing arm 334 is sensed by the grade sensor 326. This signal shifts the valve 408 to position 1 for extending the ram 60 and to position 3 for lowering the ram 60. However, as the front tractor beneath the ram 60 retracts, for example to allow the n~chine frame to remain at the pre-established slope and grade, the beam 64 must also pivot to accommodate the change in the effective distance be-tween the bogey-mounts 124 and 68 at the ends of the beam, as shown in FIG.
2. The pivot 114 allows the entire rear suspension 62 to pivot slightly in rela~i~n to the frame so that the rear tractor on this same side remains on the grade. The rear suspension 62 (ram 62 of FIG. 21) will there-fore extend slightly umder the control of the grade sensor 322, ie, move to posltion 3, so that this corner of the frame remains on grade. Also, the "

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beam 64 will pivot at each of -the cnd pivots 120 wllilc the rcar tractor remains on the grade due to its saddle mount 124 and pivot 150.
As the rear tractor on the beam 64 negotiates the change in elevation the ram 62 will retract and the suspension 62 will again pivot back to its normal vertical position. This pivotal action provided by the pivot 114 does not disturb the attitude of the front suspension means 60 nor the attitude of the single ram 70 on the other side of the machine.
The solenoid valve system shown in FIG. 21 has proven to be -fully operative to control the machine. Ilowever, a servo system can also be used using variable pressure compensated pumps and a proportional feed system or a variable flow proportional control system as supplied by Minneapolis-Honeywell Corporation.
Because of the unique action of the beam 64 as shown in FIG. 2, the machine of FIG. 20 using one such modified walking beam on opposite sides of the miain frame has some particular adv~ntages, allowing each of the suspension means to be operated individually for some types of tool control and individually and in pairs for other types of tool control.
In laying one or more lanes of pavement, using the straddle mounted tool 350 of FIG. 19, for example, and a single string line on one ~::
side of the machine for both grade and steering control, the opposite side of the machine can be under the control of a slope sensor. If a slope cor-rection is called for the rams on this opposite side can be operated simu~-taneously to make the necessary correction and either or both of the~rams on the other side can be operated individually or simultaneously to control the grade It is to be observed that at the moment the front tractor on the walking beam 72 rises up on an obstacle of say 4" height, its bogey-mount will raise that e~d of the beam about one-half that amount or 2". H~wever~
since the beam 72 is pivoted to the ram 70 at its center, the correction called for will be only 1" or half this amount again. By the time the ~' ... .

:~ ~; 3~
front tractor is central o~ the obstacle ~ul~ thc front Or the bc.~ 72 h.ls risen the full 4" in height in passing thercill t:he r(~l~ 70 will have madc itsfull connection of 2" gradu.lily so that the rate of ram opcration is rcduccd as well as the rate of change in elevation of the parts. l~le same action in reverse repeats itself as the rear end of this tra(-tor negotiates tile obstacle. As the rear tractor negotiates the obstacle, the s.-~c action and correction takes place as described for the front tractor.
The machine 10 can also be operated with the tractors 140 oriented as shown in FIG. 1 with or without the frame 12 in its extended position sh~wn in FIG. 14. In this event the hydraulic connections of lIG. 21 would be changed so that the rams 60 and 62 are under the control of the slope sensor 340 and the ram 70 is under the control of a grade sensor operating on a grade reference. In this embodiment, the rams 60 and 62 can be operated independently or one of the rams locked and the other used to control the slope. The machine could travel in either direction and preferably the machine would travel with the ram 70 in front and the rams 60 and 62 in the rear.
Since slope is a function of grade but grade is not a function of slope, if a grade change is called for by the grade sensors, in order to maintain the slope the adjustable support members 60 and 62 must extend or retract simultaneously and by the same amount. In those instances where the machine is being used with the member 60 controlling slope and the member 62 controlling grade, then each time the member 62 adjusts the member 60 must also adjust. By cross-connecting the input lines to the mem-bers 60 and 62 on both their pressure and return lines with a pilot-operat-, .
- ed lock valve, the slope can be isolated from the grade. `If the slope control calls for a correction of the member 60, the pilot-operated valves are closed and a slope correction is made without influencing the ..:
~; vertical position of the member 62. The slope and grade correc~ions, con-trolled by the adjustable support nember 60, 62 and 70 can be isolated one from the other by the use of an isolation amplifier system or a dual pilot ; ' ' .

.

valvc sys~em. Illc cros~-colu~ectin~ pilot loc~ v;llvc ~rr~)~en~nt, thc dual pilot valve systcm and the usc of ~1 iso~ation ~nplifier arc des-cribed in more detail in co-pendin~ Canadian application, Serial No. 255,919 entitled GRADE TRIMMERr filed on June 29, 1976 by the instant inventors.
lt is seen from this description that the invcntion inclu~es as a non-limiting feature the provision of a construction machinc with a main frame that is supported by a first walking beam and its associated pair of adjustable support means with a transverse or horizontal pivot on one si~c for one o the support mc~ls ~ld a second walking beam with its associated centrally mounted sin~le adjustable support mcans on the other side. Another feature of thc invention is ~he provision of a main frame of a construction machine with a walking beam and the associated pair of adjustablc s~port mcans and pivot on opl~ositc sidcs thcrcof.
The ground engagement means can be wheels, skids or tractors, ie, track frames carrying an endless track or the like with or without individual power drive means therefore, and the suspension of this in-. .~. .
vention can be used on small or large machines. A feature of this as-pect of the invention is that the gro~d engagement means are individually steerable about their respective vertical s~eering axes ~nd ~he steering is co-ordinatable whereby the pair of ground engagement means on the ends of one Or the walking bcams and thc ~air of ~round cngagcl~nt means on the ends of the other walking beam are selectively steerable in unison in a direction of travel subst~ltially pe~)endicular to or at an angle ~o the : 25 longitudinal axis of said walking beams. Because the steering means are capable of turning the ground engagemcnt mcans more ~han 90 about the vertical steering axis, the steering means are also co-ordinatable so th~t ~he pairs of ground engagement means on the adjaccnt or opposite front and , ' ' ) 1, ' : I
:

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rear ends of the walking beams, wllile in tandcm relationship along the longitudinal ~Yis of the beanls, are selectively orien~able and steerable in pairs in a direction oE travel parallel to the walking heams.
Likewise, each of the ground engagement means includes, in one embodiment, a power drive means to propel the ground engagemcnt me.uls in the selected direction of travel. The power drive means are individually controlled and also co-ordinatalbe whereby in either of the steering pOsitiolls or paths of travel of the machine, the front and rear pairs of the ground engagement means are driven at the same or different speeds and the front and rear ground engagement means in tandem position along a walking beam or in a position wherein their longitudinal axes are per-pendicular to a walking beam can be driven at the same or different speeds from that of the front and rear ground cngagemcnt means in the opposite positions in relation to the walking beams. As long as the machine is on a prepared grade and traveling along a substantially linear path all four ground engagement means are normally operated at the same or about the same speed. Uhder these conditions the negotiation of a curve is facilitated by speeding up the pair of ground engagement means on the outside of the curve or slowing down the pair on the inside of the curve.
When adverse grade conditions are encountered involving obstacles, depressions or mud, it is advantageous to be able to selectively speed up or slow down one or more of the ground engagement means so that the for-ward motion of the machine is not lost and the machine does not dig it-self into the grade. Various types of speed control valves are available for this purpose when hydraulically-driven motors are used to propel the ground engagement means. Also a variable pressure compensated pump can be used to selectively control each drive motor, or pairs of drive motors, , .

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t ~ 6 ~ J a) SU~I IS iS dcscril)e~ .t~7CO-pClld.ill~ Ipl)liC~tiOIl Scrial No. ~15-j76~.
Since the use o~ spee~ control valves ~1~ pressure co~ensatcd pumps in this manner is known in the art~ no further description is necessary.
l~is versatility in the suspellsion ~d st~erillg furthcr providcs for the use of a tclescoping or adjustablc fr~ne with or wi-thout friction-reducing means along the telescoping parts whereby the power of the machine can be used in extending and retracting the fr~e. ~ese features of the invention allow the use of a variety of growld wo-rking ~ools~ scree~s, and slipforms to be carried by ~Ic main fr~nc in different locations whercby the machine and its working tool are best fitted ~o perform the intended work and thc slope, grade an~ stecring s~nsors can be locate~ abou-t the frame in the most convellicllt ~ld accuratc positions.
Other modifications of the machine can be incorporated.
Thus, to maintain better control of slope, the single input system shown for the control of the one-way ram 70 in FIG. 21 is replaced by using valves like 412 and 414 in place of the valve 404 and the return to sump ellminate~. AI.so, it is to be understood that feed back loops are to be included in the system shown in FIG. 21 under circumstances where over correction and hunting are to be prevented~ FIG. 21 disc~oses but one steering sensor (342 front) for the pair of front tractors and one steering sensor (344 rear) for the rear tractors.
This is for illustration and initiation of the control. Actual-ly~ each tractor will have i~s own s~eering control system and steer ing sensor to either follow a reference or be slaved to a corre-spondin& tractor unit for parallel control or tandem control.
This is accomplished through the use of the sensors 506 ~FIG. 3 ..

'' .

on each tractor 140, associated feed back loops connected between said sensors on a front and rear pair of tractors, wlth the sensors 506 of the tandem tractors being connected to the respective front and rear steering sensors that are taking their signal from the steering referenceO

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Claims (6)

1. A construction machine comprising:
a main frame;
a first pair of vertically adjustable main frame support means spaced along one side of said main frame;
a first walking beam extending along said one side of said main frame and pivotally mounted to each of said main frame support means;
one of said first pair of main frame support means being pivotally mounted to said main frame on a horizontal axis above and in substantially the same plane as its respective pivotal mount on said first walking beam;

a second pair of vertically adjustable main frame support means spaced along the other side of said main frame;
a second walking beam extending along said other side of said main frame;
one of said second pair of main frame support means being pivotally mounted to said main frame on a horizontal axis above and in substantially the same place as its respective pivotal mount on said second walking beam;
ground engagement means adapted to transport said machine pivotally mounted on means defining individual vertical steering axis at the ends of said walking beams to steer said machine; and said ground engagement means being positionable about said steering axes to transport said machine in a plurality of selected paths extending 360° around each of said steering axes.

2. A construction machine in accordance with Claim 1 in which:
said ground engagement means each include an elongated track frame carrying an endless track thereon;
saddle means are provided for each of said track frames;
said saddle means each being pivotally connected to said track frames on an axis transverse the longitudinal axis thereof and intermediate their ends;
each of said saddle means is mounted from the indivi-dually vertical steering axes at the ends of said walking beams;
means are provided to individually steer each of said track frames and endless tracks about its respective vertical steering axis to turn same into a steering position wherein said endless tracks are oriented to transport said machine in said plurality of paths; and said steering means being co-ordinatable whereby in either of said positions the front and rear pairs of said endless tracks are steerable in unison and independent of each other.

3. A construction machine in accordance with claim 1 wherein:
said main frame includes two telescoping sections each being attached to one of said walking beams through the associated main frame support means; and means are provided to extend and retract one section of said main frame in relation to the other section whereby the effective width of said main frame is adjustable.

4. A construction machine in accordance with Claim 3 in which:
each of said ground engagement means includes an individual power unit operable to drive a pair of said ground engagement means associated with one of said walking beams and its telescoping section in unison whereby the pair ground engagement means on either side of said main frame is operable to extend and retract said main frame against the holding force of said pair of ground engagement means on the other side of said main frame.

5. A construction machine in accordance with Claim 1 in which:
the horizontal pivotal mount of said one frame support means on said one side of said main frame and the horizontal pivotal mount of said one frame support means on said other opposite side of said main frame are at adjacent corners of said main frame.

6. A construction machine in accordance with Claim 1 in which:
the horizontal pivotal mount of said one frame support means on said one side of said main frame and the horizontal pivotal mount of said one frame support means on said other opposite side of said main frame are at diagonal corners of said main frame.