US3039789A - Hydraulically controlled tandem suspension for graders - Google Patents

Description

June 19, 1962 A. w. SCHNUERLE 3,039,739

HYDRAULICALLY CONTROLLED TANDEM SUSPENSION FOR GRADERS Filed June 17, 1960 3 Sheets-Sheet 1 Fig. 2

% Arthur M. Sc/muerle INVENTOR.

June 19, 1962 A. w. SCHNUERLE 3,039,789

I HYDRAULICALLY CONTROLLED TANDEM SUSPENSION FOR GRADERS Filed June 17, 1960 3 Sheets-Sheet 2 Arthur M. Schnuerle 1NVENTOR.

BY WWW MM,

June 19, 1962 A. w. SCHNUERLE 3,039,789

HYDRAULICALLY CONTROLLED TANDEM SUSPENSION FOR GRADERS Filed June 17, 1960 5 SheetsSheet 5 v 5 N a, N

g R a? 8% Arthur W Schnuer/e -1NVENTOR.

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BY (um Wavy 3% tilted States 3,039,78 Patented June 19, 1962 line 3,939,789 HYBRAULICAILLY CONTRGLLED TANDE v Z SUSPENSIQN FOR GRADERS Arthur W. Schnnerle, R0. Box 191, Aberdeen, S. Bait. Filed June 17, Mel), Ser. N 36,8d9 7 (liairns. (Q1. 280 194.:)

The present invention generally relates to tandem suspension systems, and more particularly to such a system for road graders having a tandem wheel suspension, and incorporates a hydraulically controlled mechanism for applying force to the tandem suspension assemblies to reduce oscillation of the tandem assemblies about a transverse axis.

The major problem in grading with a road grader is the tendency of the tandem wheel suspension of the road grader to oscillate about a transverse axis when grading at speeds of three to four miles per hour or higher. This tendency of the tandem wheel suspension to oscillate is known as galloping and results in a quite uneven surface left by the grader blade since the grader blade will also move vertically during the oscillation of the tandem wheel assembly about a transverse axis. It is the primary object of the present invention to eliminate completely the galloping of the tandem wheel suspension, thus permitting an increase in working speed of from 50% to 100% and also provide smoother blade operation thus leaving a smoother surface to the grade.

The primary object is accomplished by providing a pair of hydraulically controlled rams mounted on the grader frame adjacent the rear thereof, together with an abutment on the rear of each tandem assembly so that the ram may come into engagement with the abutment and exert pressure downwardly, thus preventing oscillation of the tandem assemblies about a generally centrally disposed transverse axis.

A further object of the present invention is to provide an arrangement in accordance with the preceding object which is automatically rendered effective and ineflective by the operator merely controlling the supply and discharge of pressurized hydraulic fluid to the hydraulic rams.

The above object is accomplished by pivotally mounting each of the rams from the grader frame and providing a relatively strong spring on one side of the pivot axis between the frame and the ram and a relatively weak spring on the other side of the ram and connected between the frame and the ram, with the weaker spring being still effective after the stronger spring has completely collapsed whereby extension of the ram will stretch the weaker spring and also the stronger spring, whereby the stronger spring will pivot the ram about its pivotal connection with the frame and thus bring the ram into engagement with the abutment on the tandem assembly and will retain the ram in engagement with the abutment on the tandem assembly as long as the ram is extended, whereby the force exerted on the tandem assembly will prevent oscillation of the tandem assembly about the transverse axis of attachment of the tandem assembly to the frame. When the ram is retracted, the stronger spring will be effective initially until it is completely collapsed, in which event the weaker spring then takes over and pulls the ram to a retracted position out of the way of movement of the abutment on the tandem assembly, thereby enabling the tandem assembly to operate normally so that it may move when the grader passes over uneven terrains so that the tandem assembly may operate in the manner and for the purposes for which it was constructed.

Another important feature of the present invention is to provide an arrangement whereby the tandem assembly on a road grader may be precluded from oscillating, thus preventing galloping of the grader, with the assembly being quite easy to attach to existing road graders, both as to structure of the device itself and as to the control mechanism which employs the hydraulic pressure normally provided on road graders of this nature and employing a conventional control valve operated from the operators seat in the same manner as the other control valves normally provided on a road grader, thereby requiring very little thne in installing the device.

Still another feature of the present invention is to provide a control device for controlling oscillation of the tandem wheel suspension on road graders which is simple in construction, easy to use, eifective for its particular purposes and relatively inexpensive to manufacture, install and maintain.

These, together with other objects and advantages which will become subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being bad to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a side elevational view of a road grader with portions of the rear tandem wheel b oken away illustrating the control device for the tandem suspension of the present invention installed;

FIGURE 2 is a rear elevation of the grader illustrating the structure of the control device of the present invention;

FIGURE 3 is a detail sectional view taken substantially through the center of the control device illustrating the structural arrangement thereof;

FIGURE 4 is an enlarged perspective view illustrating the mounting bracket for the hydraulic ram and the orientation of the relatively light spring in relation to the ram;

FIGURE 5 is a side elevation of the control device in normally inoperative or ineffective position;

FIGURE 6 is a side elevational View illustrating the intermediate position of the control device as the ram starts expanding and swinging towards engagement with the abutment;

IGURE 7 is a side elevational view of the control device illustrating it in operative or effective position; and

FIGURE 8 is a view similar to FIGURE 6 illustrating the ram retracting and the heavy spring fully collapsed, with the light spring beginning to swing the ram rearwardly to an out-of-the-way position so that the abutment will not engage the ram during normal movement of the tandem suspension.

Referring now specifically to the drawings, the numeral 10 generally designates the control device of the present invention which is illustrated on a conventional road grader which includes the usual frame 12, front steerable wheels 14, a steering wheel 16, a grader blade 18, rear tandem wheels 24) and 22, and a suspension beam or walking beam 24 interconnecting the tandem wheels 20 and 22 and connected to the frame 12 by a dead axle 26. All of the foregoing represent conventional road grader constructions except for the control device 10 and it is also pointed out that the grader is provided with a hydraulic system with a hydraulic pump for supplying pressurized hydraulic fluid for controlling operation of the grader blade in the usual manner. The operators compartment or cockpit 28 is provided with the usual control valve for the hydraulic system. In order to operate the control mechanism of the present invention, a hydraulic line 29 extends to the hydraulic system and is controlled by a conventional control valve in the cockpit or operators area of the road grader. Since this is conventional structure, it is not disclosed specifically in the present application. Further, while the invention has a primary use s eaves in combination with a road grader, it will also be xtremely useful in other types of equipment employing tandem suspension assemblies in order to prevent oscillation of the tandem assemblies about the dead axle under certain desired conditions. It is pointed out that normally the tandem assemblies are operative for the purposes intended such as to permit oscillation of the tandem wheels during movement over rough terrain. However, in certain other instances, it is desired to prevent such oscillation, and in conjunction with a road grader, this is quite desirable in order to eliminate galloping which leaves the blading rather rough due to vertical oscillation of the grader blade. By eliminating oscillation of the tandem assembly, oscillation of the grader blade can be eliminated, thus allowing an increase in the working speed of 50% to 100% and increasing the smoothness of the blading. Further, it is noted that while the present invention is described in conjunction with a hydraulic system, it may also be employed with a pneumatic system if desired.

As illustrated in FEGURE 1 and also in FIGURES 58, the tandem assembly or walking beam 24 is provided with a rounded rear end portion or surface to which is welded an abutment 32 which may be conveniently in the form of an L-shaped member having one flange generally curved to conform to the surface 30 and welded thereto as indicated by numeral 34. In this construction, the abutment 32 is normally downwardly inclined and rearwardly extending as illustrated in FIGURES 58. When the walking beam oscillates, the abutment 32 will swing in an arcuate path generally about the center formed by the dead axle 26. During high speed grading, that is, above three to four miles per hour, there is a tendency for the tandem assembly to oscillate about the dead axle 26 due to several different forces being applied to the tandem driving wheels.

In order to eliminate the galloping, the control device 19 is provided and this includes a plate 36 secured to the frame 12 by bolts or other suitable fastening means 38. Since the interior of the frame 12 is easily accessible, the plate 36 may be secured by bolts or the like or, if desired, it could be welded to the frame 12. Projecting outwardly from the plate 36 is a horizontally disposed top plate 40 and a pair of depending side plates or gussets 42 which have inclined lower edges 44. Rigidly interconnecting the gussets and also rigidly attached to the top plate 49 is a pair of vertical mounting plates 46 and 48 through which a pin 58 extends. The pin 56 is in perpendicular relation to the surface of the frame 12 and is provided with a headed outer end and the inner end is provided with a removable fastener 52 and a washer 54. This may be of any convenient structure such as a cotter pin and washer assembly.

Mounted on the pin 56 is a hydraulically operated piston and cylinder assembly generally designated by numeral 56 and including a cylinder 58 having a longitudi nally extending mounting lug 60 pivotally supported on the pin 50, with the pin 54 extending through a transverse bore 62 therein. The mounting plates 46 and 48 prevent any substantial lateral movement of'the cylinder 58, but the pin 59 permits pivotal movement of the cylinder 58 within the limits defined by engagement of the mounting lug 60 with the bottom edge of the gusset plates 42 which are undercut or recessed, as designated by numeral 64, to form a definite limit for the movement of the cylinder 58. Also, the lug 68 is provided with a bore 66 extending into the interior thereof from the interior of the cylinder and the hose 29 is attached to the lug 60 and is in communication with the bore 66.

Slidable in the cylinder 58 is a piston 68 having a piston rod 70 extending downwardly through the lower end 72 of the cylinder 58 with the piston rod 70 being sealed in relation to the lower end 72 of the cylinder 58 and also with the piston 68 being sealed in relation to the interior of the cylinder 58. This represents conventional fluid pressure operated piston and cylinder arrangements so that when pressure is admitted into the interior of the upper end of the cylinder, the piston will be forced outwardly, thus forcing the piston rod outwardly.

The lower end of the piston rod 70 is provided with a surface 74- for engagement with the abutment 32. Also, one side of the lower end portion of the piston rod 79 is provided with a loop 76 thereon of relatively short construction while the other side of the piston rod 70 is provided with a longer loop 78 thereon, with the loops 76 and 78 being disposed at diametrically opposed points at the forward and rear surface of the piston rod. The forward gusset plate 42 is provided with a loop 80 thereon while the rear gusset plate 42 is provided with a rearwardly and downwardly inclined bracket 82 having a plurality of longitudinally spaced apertures 84 therein. The loops 76, 73 and 89 as well as the bracket 82 are all welded to their respective supporting plates. Extending between the loop 76 and the loop 80 is a coil tension spring 86 which is relatively a heavy spring and which has a relatively short length and which, when the hydraulic cylinder is completely collapsed, is, itself, compietely relaxed and, in fact, is slightly loose between the loops 76 and 89. Extending between the loops 78 and one of the apertures 84- in the bracket 82 is a tension coil spring 88 which is longer than the spring 86 and which is of lesser diameter and which is of less strength than the spring 86. The spring 88 like the spring 86 is provided with hooks 90 for engagement with the loop 78 and for engagement with one of the apertures 84.

For limiting the inward movement of the piston rod 7 0 into the cylinder 58, the piston rod 70 is provided with a flange 92 thereon which will engage the lower end of the cylinder during inward movement of the piston, thus limiting the inward movement of the piston 68 so that it will always be spaced from the top end of the cylinder 58 for providing a working surface area for the fluid pressure whether it be hydraulic or pneumatic.

Also, while the tandem stabilizer has been illustrated on the rear surface of the tandem suspension or walking beam, it could also be incorporated onto the forward end thereof with the same results. Further, the device may be used on any tandem wheel assembly when it is desired to automatically render the tandem suspension ineifective or effective, thus providing such equipment with an oscillatable tandem assembly when the tandem suspension operates normally or a rigid tandem assembly when the control device of the present invention is actuated. Further, the device may be operated by any suitable fluid pressure, either pneumatic or hydraulic, and the device may be inverted, that is, the piston attached to the frame with the cylinder movable into and out of engagement with the abutment on the tandem assembly. Further, it is within the purview of the present invention that in some installations it may be desirable to mount the expanding fluid pressure operated cylinder and piston arrangement on the tandem assembly with the abutment on the frame and, further, it is within the purview of the invention to have the abutment manufactured as an internal part of the suspension assembly or frame and also this may be true of the bracket for supporting the fluid pressure operated piston and cylinder arrangement. On some models and makes of motor graders, the frames do not extend rearwardly a s-ufficient distance to support the piston and cylinder arrangement. Therefore, frame extensions may be provided for use with these models and makes.

During operation of the device, the downward stroke of the piston causes the heavy spring to pull the hydraulic ram forward for making contact with the brackets or abutments secured to the housing of the tandem. When the hydraulic pressure is released, the big spring in front pulls the ram back up and then the little or smaller spring pulls the cylinder back out of the way after the big spring has been completely collapsed, whereby the motor grader then can go over rough terrain, giving full oscillation to the tandem as intended. This method of swinging the ram in and out of position is automatically operated from the operators platform, thus requiring no special attendant to set the mechanism, which may be considered a tandem lockup mechanism.

In actual use of the stabilizers of the present invention, it has been found that the smoothness of finished road surfaces is greatly enhanced. Normally, when laying base courses and taking material out of the Windrow, the conventional motor grader has generally the same movement as an automobile going across a cornfield at a 30 to 40 degree angle to the corn rows which gives the automobile a side sway. Motor graders sway sideways in the same manner when taking material out of the windrow which tends to separate the granular graded material. Then, when the rollers pass over the roughened surface, it is compacted and after the motor grader makes a second or third round the rocking movement is increased. The stabilizer of the present invention completely eliminates side sway and rocking, thus producing a smoother base course and finished road surface.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A stabilizing device for the tandem wheel suspension assembly of a road grader comprising an abutment adapted to be mounted on a movable portion of the tandem assembly in spaced relation to the pivotal axis of the tandem assembly, a fluid pressure operated piston and cylinder arrangement adapted to be pivotally mounted on the frame of the grader, said piston and cylinder arrangement including a movable component for engaging with and applying force to the abutment when the piston and cylinder arrangement is extended, thereby preventing movement of the abutment toward the piston and cylinder arrangement, said device including a laterally extending bracket adapted to be mounted on the frame of the grader, means pivotally connecting the upper end of the piston and cylinder arrangement to the bracket for pivotal movement thereof about an axis generally paralleling the axis of pivotal movement of the tandem suspension assembly, and means interconnecting the piston and cylinder arrangement and the bracket in spaced relation to the pivotal connection between the piston and cylinder assembly and the bracket for moving the lower end of the piston and cylinder arrangement in an arcuate path towards and away from the abutment for engagement therewith in response to extension and retraction of the piston and cylinder arrangement.

2. The structure as defined in claim 1 wherein said means for swinging the piston and cylinder arrangement arcuately includes a heavy spring interconnecting the bracket and the lower end of the piston and cylinder assembly at the forward surface of the lower end of the piston and cylinder assembly, and a light spring interconnecting the other side of the piston and cylinder arrangement with the bracket whereby initial expansion of the piston and cylinder arrangement will pivot the piston and cylinder arrangement forwardly due to the force exerted by the heavy spring, thus bringing the lower end of the arrangement into overlying relation to the abutment, said light spring pulling the piston and cylinder arrangement rearwardly after the heavier spring has been completely collapsed, thereby swinging the piston and cylinder arrangement to an out-of-the-Way position.

3. In combination, a vehicle frame, a tandem wheel suspension member pivotally mounted on said frame for oscillation about a transverse axis, an abutment on one end'of the tandem suspension member, said abutment extending longitudinally from the member in spaced relation to the pivotal axis thereof, a bracket mounted on the frame generally in overlying relation to the abutment and spaced vertically therefrom, a fluid pressure operated piston and cylinder assembly pivotally supported from the bracket and disposed in depending relation therefrom, means communicating with the interior of the piston and cylinder assembly for supplying pressurized fluid for extending the piston and cylinder arrangement, means on the lower end of the piston and cylinder arrangement for engagement with the abutment and applying force thereto, thereby substantially reducing oscillation of the tandem suspension member when the piston and cylinder assembly is extended and the means on the lower end thereof is in engagement with the abutment, the lower end of the piston and cylinder assembly being provided with upwardly diverging coil spring members attached to the opposite sides thereof, means connecting the coil spring members to the bracket in spaced relation to the pivotal connection between the piston and cylinder assembly and the bracket, one of said springs being weaker than the other and longer than the other, the shorter spring being stronger and causing pivotal movement of the piston and cylinder assembly about the pivotal axis of connection between the piston and cylinder assembly and the bracket when the stronger spring is extended, thus swinging the piston and cylinder assembly arcuately for bringing the means at the lower end thereof into engagement with the abutment, the longer spring swinging the piston and cylinder assembly arcuately away from the abutment after the shorter and stronger spring has been completely collapsed, thereby enabling movement of the abutment and the tandem suspension member in an oscillatory manner without interference by the piston and cylinder assembly.

4. The combination of claim 3 wherein said longer spring is attached to a laterally extending bracket having a plurality of openings therein for adjustably receiving one end of the longer spring, thereby varying the tension of the spring when the piston and cylinder assembly is completely collapsed, assuring that the piston and cylin der assembly will not swing back into the path of movement of the abutment.

5. The combination of claim 4 wherein said bracket is provided with gusset plates, mounting plates interconnecting the gusset plates, a pin extending through the mounting plates and pivotally supporting the piston and cylinder assembly therefrom, said gusset plates having recessed lower edges for engagement with the piston and cylinder assembly for limiting the pivotal movement thereof.

6. In combination with a road grader having a frame, a tandem wheel assembly including a supporting member, a dead axle pivotally supporting the member from the frame for oscillation about a transverse axis, said supporting member having an abutment thereon extending longitudinally therefrom, said frame including a laterally extending bracket normally overlying the abutment in vertically spaced relation, a hydraulically operated piston and cylinder arrangement pivotally attached to the bracket and having an extensible piston rod for engagement with the abutment and applying force thereto for preventing oscillation of the supporting member for the tandem wheels when the piston and cylinder arrangement is expanded, a flexible hose for connecting the piston and cylinder arrangement with the hydraulic system of the road grader for extending and retracting the piston and cylinder ar rangement, a light spring interconnecting the piston rod and the bracket on one side of the piston and cylinder arrangement, a light spring interconecting the piston rod and the bracket on the other side of the piston and cylinder arrangement and being continuously under tension with the heavy spring being completely collapsed normally, the continuous tensioning of the light spring maintaining the piston and cylinder arrangement out of alignment with the engagement with the abutment, said heavy spring swinging the piston and cylinder arrangement arouately in a vertical plane longitudinally of the grader during expansion of the piston rod, thus bringing the lower end of the piston rod into engagement with the abutment for locking the suspension member from rotation or oscillation about a transverse axis, said lighter spring returning the piston and cylinder arrangement to an out-of-the-Way position when the hydraulic pressure is exhausted and the heavier spring has completely collapsed the piston rod and has completely relaxed itself.

7. A stabilizing device for use in a vehicle suspension system having a frame component and a Wheel carrying component for preventing relative movement of the components toward each other, said stabilizing device comprising a projecting abutment rigid with one of said compone ents, a fluid pressure operated piston and cylinder assembly, means pivotally supporting said assembly on the other of said components, said assembly being spaced from said abutment when retracted, and means interconnecting said assembly and the other of said components for pivoting the assembly into alignment with the abutment upon initial expansion of the assembly with additional expansion of the asseirrbly serving to bring the assembly into engagement with the abutment.

References Cited in the file of this patent V UNITED STATES PATENTS 1,742,636 Collins Jan. 7, 1930 2,721,405 Gardner Oct. 25, 1955 2,837,312 Troche June 3, 1958 2,873,124 Walker Feb. 10, 1959 2,882,623 Gardner Apr. 21, 1959

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