Patent Publication Number: US-8118111-B2

Title: Grader stabilizer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to earth moving equipment, and more particularly, to an improved earth moving grader stabilizer. 
     2. Description of the Related Art 
     Several designs for improvements to earth moving equipment have been designed in the past. None of them, however, includes a device that stabilizes an earth moving grader blade of small to medium-sized track-steer or skid-steer vehicles using a remote grade controller system. 
     Applicant believes that the closest reference corresponds to U.S. Pat. No. 4,893,683 issued to Horsch. However, it differs from the present invention because the Horsch device attempts to stabilize the dozer blade by geometry of the brackets and slots supporting the blade. The present device stabilizes the dozer blade by limiting only one axis of movement which permits greater control of the blade and stabilizes the blade for more precise control. 
     Other patents such as U.S. Pat. No. 4,923,015 issued to Barsby attempt to control a dozer blade by complex electronic sensing and mechanical correcting equipment where the present device uses a simple fixed bracket to instantly prevent unwanted blade movement instead of correcting the movement as it happens. 
     Other patents describing the closest subject matter provide for a number of more or less complicated features that fail to solve the problem in an efficient and economical way. None of these patents suggest the novel features of the present invention. 
     SUMMARY OF THE INVENTION 
     It is one of the main objects of the present invention to provide a device that grades a wide variety of soil types and site conditions in a highly accurate way. 
     It is another object of the present invention that does not require any additional ground contacting stabilizers. 
     It is another object of this invention to provide a device that can maneuver in restricted space and around sensitive objects and substrates. 
     It is still another object of the present invention to provide greater functionality to small to medium skid steer and track steer vehicles while retaining their ability to be used with the wide variety of available accessories. 
     It is yet another object of this invention to provide such a device that is inexpensive to manufacture, light weight and easy to maintain while retaining its effectiveness. 
     Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With the above and other related objects in view, the invention consists in the details of construction and combination of parts as will be more fully understood from the following description, when read in conjunction with the accompanying drawings in which: 
         FIG. 1  represents a side elevation view of a track steer vehicle. 
         FIG. 1A  is a perspective view of a track steer vehicle with the present device included. 
         FIG. 2  shows a perspective view of the prior state of the art. 
         FIG. 3  is a front elevation view demonstrating blade roll left. 
         FIG. 4  is a front elevation view demonstrating blade roll right. 
         FIG. 5  is a top plan view demonstrating blade yaw left. 
         FIG. 6  is a top plan view demonstrating blade yaw right. 
         FIG. 7  is a side elevation view demonstrating blade lift low. 
         FIG. 8  is a side elevation view demonstrating blade lift high. 
         FIG. 9  is a side elevation view demonstrating blade pitch back. 
         FIG. 10  is a side elevation view demonstrating blade pitch forward. 
         FIG. 11  is a partial perspective view of a blade assembly with a partial cut away. 
         FIG. 12  is a partial perspective view of a blade assembly. 
         FIG. 13  is a partial perspective view of a blade assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Skid steer vehicles are commonly commercially available. The skid steer vehicle that is preferred to work with the present device is small to medium sized and designed to accept any of a variety of front end accessories such as a dozer blade, pallet forks, a mower, a hole digger and several others. These front end accessories can be interchanged relatively easy with one or two men in a few minutes. The popularity of the small to medium sized skid steer class of vehicle is owed largely to the availability of the front end accessories by allowing a single vehicle to accomplish a wide variety of tasks without the need for specialty vehicles. 
     Grade control systems, such as laser automation, are commonly commercially available. An example is disclosed in U.S. Pat. No. 5,375,663 issued to Teach. Generally, the system works with a laser reference beacon erected on an edge of a job site at a known location and elevation established by survey. A laser receiver is attached to earthmoving equipment, typically onto the ground contacting blade, and sends a signal to a computer accessible to the operator of the earthmoving equipment. The computer is able to determine if the blade is above or below the desired grade and make adjustments as necessary to the blade height by controlling the hydraulics that move the blade. 
     What is claimed is a bracket. Said bracket is attached to a small to medium sized skid steer vehicle. Said skid steer vehicle having a main arm onto which various commercially available attachments could be connected to the skid steer vehicle. The skid steer vehicle having a dozer blade attachment attached to the main arm. Said dozer blade attachment having a hydraulic causing a pitch axis of movement of the dozer blade attachment relative to the main arm. Said bracket connecting said main arm and said dozer blade attachment to prevent movement of said hydraulic while retaining other available axis of movement of said dozer blade attachment and also being disconnectable from either or both of said main arm and dozer blade attachment. 
     The device may also include an automatic grade control system such as a laser leveler system with a remote laser beacon, a global positioning system automatic leveler or other system to aid the user of the device properly grade a surface. 
     The device may also comprise additional bracket(s) connecting said main arm and said dozer blade attachment to prevent movement of said hydraulic while retaining other available axis of movement of said dozer blade attachment. The additional bracket(s) may be disconnectable from either or both of said main arm and dozer blade attachment. 
     The bracket may be dimensioned so that when the lower edge of said dozer blade attachment is at the same height as the bottom edge of said skid steer vehicle then the leading edge of said dozer blade attachment is substantially vertical. 
     The bracket attaches the main arm to the frame of a dozer blade assembly on a small to medium-sized skid steer vehicle that directly prevents the hydraulic responsible for pitch thereby stabilizing the dozer blade and a automatic grade leveling system to control the lift axis of the dozer blade. 
     Referring now to the drawings, where the present invention is generally referred to with numeral  10 , it can be observed that it basically includes a tractor assembly  12 , a track assembly  18 , a blade assembly  30  and a leveler assembly  80 . 
     Said tractor assembly  12  comprises, inter alia, an operator cage  14  and an engine case  16 . An operator of the vehicle sits inside of and operates the vehicle from inside the operator cage  14 . An engine inside the engine case  16  typically powers the vehicle including any hydraulics. 
     Said track assembly  18  comprises, inter alia, a suspension  20  and a track  22 . In most applications a track steer vehicle will have complementary track assemblies  18  on both sides of the vehicle. 
     Said blade assembly  30  comprises, inter alia, a hydraulic  32 , a hydraulic  36 , a hydraulic  38 , a frame  40 , a bracket  42 , a frame  44 , a blade  46  and a main arm  48 . 
     Said leveler assembly  80  comprises, inter alia, a receiver  82 , a mast  84 , a cable  86  and a bracket  88 . 
       FIG. 1A  is an alternate view of the skid steer vehicle shown in  FIG. 1 . 
     Referring now to  FIG. 2  where the prior state of the art is shown to include, inter alia, a leveler assembly  90 , a hinge  91 , a hydraulic  92 , a hinge  93 , a blade  94 , a wheel  95 , a skid steer vehicle  96  and a receiver  97 . 
     Said leveler assembly  90  is one of several front end accessories designed to work with small to medium skid steer vehicles  96 . Said leveler assembly  90  is designed to be used with a grade control systems, such as laser automation. When in use grading soil an operator sits inside the skid steer vehicle  96  and programs a computer controller for the grade control system with a predetermined grade. Generally, the grade control system requires a remote beacon fixed at a known location. Typically the beacon is a laser set in place by a job surveyor on the edge of a job site. The receiver  97  is fixed relative to the blade  94  on a mast and receives a signal from the beacon. The computer controller is connected to the receiver  97  and determines whether the receiver  97 , and thus necessarily the blade  94 , are at the proper height for the predetermined grade. The computer controller automatically actuates the hydraulic  92  to adjust the height of the blade  94  relative to the wheels  95 . Hinges  91  and hinge  93  bend as the hydraulic  92  is adjusted to the proper height. 
     The wheels  95  are necessary to carry the weight of the leveler assembly  90  for precise adjustment of the blade and stability of the leveler assembly  90 . As can be appreciated by a user of a leveler assembly  90 , because of the wheels  95  placement forward of the blade  94 , the blade  94  cannot be brought closer to an object than the distance between the wheels  95  and the blade  94 . This is often problematic when, for example, foundation piers (or other obstructions which cannot be graded over) have been placed prior to final grading of the job site. The solution has been to use the leveler assembly  90  as shown in  FIG. 2  to rough-in the job and then grade by hand with a shovel or rake up to obstructions that the leveler assembly  90  was not able to get close enough to. 
     Another limitation of the prior art leveler assembly  90  as shown in  FIG. 2  manifests itself when the leveler assembly  90  is used to grade rough surfaces or coarse material. A problem often occurs when the skid steer vehicle  96  is moving forward and the wheels  95  are leading. If wheels  95  encounter uneven surface, for example a rut, the wheels  95  will drop and cause the blade  94  to cut too deeply. Conversely if the wheels  95  encounter a protrusion, for example a rock, the wheels  95  will tend to climb the protrusion and lift the blade  94  above the required grade. 
     Yet another limitation of the prior art shown in  FIG. 2  will be apparent to users of a similar prior art device is encountered when it is desirable to reverse the skid steer vehicle  96  and drag the blade  94  to contour the surface in confined spaces. The prior art shown in  FIG. 2  functions well only while the skid steer vehicle  96  is moving forward. 
     Still another limitation of the prior art as shown in  FIG. 2  is manifested when the desired grade is anything but flat and horizontal and perpendicular to plumb. In other words, the prior art is not readily capable of producing an inclined or sloped grade, only flat and level. 
     Now referring to  FIGS. 3 and 4  where a front elevation view of a skid steer vehicle with a dozer blade attachment is shown. These views are to demonstrate the roll axis that the operator of the vehicle can move the blade. The roll axis is typically manipulated to produce an incline or sloped grade. The roll axis is controlled by hydraulic  36 . 
       FIGS. 5 and 6  are a top plan view of a skid steer vehicle with a dozer blade attachment demonstrating the yaw axis that the operator of the vehicle can move the blade. The yaw axis is typically changed to push soil to one side of the skid steer vehicle. The change in yaw can be helpful in moving soil as part of the grading process. The yaw axis is controlled by hydraulics  38 . 
       FIGS. 7 and 8  are a side elevation view of a skid steer vehicle with a dozer blade attachment demonstrating the lift axis that the operator of the vehicle (or the automatic grade control) can move the blade. The lift axis is powered by hydraulics  32 . The grade control system as controlled by the leveler assembly  80  moves the blade  46  automatically on the lift axis by controlling the hydraulics  32 . 
       FIGS. 9 and 10  are a side elevation view of a skid steer vehicle with a dozer blade attachment demonstrating the pitch axis that the operator of the vehicle can move the blade. The pitch axis is of limited value when grading earth with a dozer blade  46 . The pitch axis control is of greater importance when the skid steer vehicle is used with, for example, a scoop or bucket front end accessory so that material may be picked up in the scoop or bucket, carried to another location and then pitched forward to dump the contents. Other front end accessories may also benefit from the pitch axis of movement. The pitch axis is controlled by hydraulics  34 . 
     A problem often arises when a small to medium sized skid steer is combined with an automatic grade control such as the laser automation as described above and including the leveler assembly  80  attached to the blade  46 . The leveler assembly  80  measures the height of the blade  46  as compared to the remote beacon (not shown in the figures and described above) and adjusts the height of the blade  46  by controlling the hydraulics  32 . The entire weight of the blade assembly  30  is held relative to the main arm  48  by the hydraulic  34 . Hydraulic  34  is also responsible for the pitch axis of the blade  46 . Hydraulic  34 , due to the weight of the blade assembly  30 , motion of the skid steer vehicle over terrain and other factors allows a bounce or movement between the main arm  48  and the blade assembly  30  which in turn imparts movement to the mast  84  and therefore also the receiver  82 . This is the bouncing dozer blade problem. 
     Said bounce imparted onto the receiver  82  then gives the automatic grade control indication that the blade  46  is not at the correct height and the automatic grade control attempts to correct the movement by controlling hydraulic  32  to adjust the blade  46  height. This bounce and correction often cause a harmonic or further bounce to develop and causes the blade  36  to constantly move therefore the grade cannot be maintained. The faster the skid steer vehicle moves, the worse the bounce becomes. 
     A solution to the bouncing dozer blade problem has been employed in the prior art by not including a means to manipulate the pitch axis of the blade on the vehicle. This is commonly found in larger earthmoving equipment and is effective to stabilize many automatic grade control systems, such as a laser leveling system. This type of equipment is commonly called a bull dozer and generally performs the single function of grading soil. 
     Presumably by removing the blade pitch means on a small to medium skid steer vehicle the vehicle could employ an automatic grade control system such as a laser leveling system. However, small to medium sized vehicles are prized in large part to the availability of various interchangeable attachments as described above. By removing the pitch axis of movement the versatility of the machine would be somewhat reduced. 
     Several problems arise with the use of larger earth moving equipment. On confined job sites the maneuverability of smaller machines is essential to reduce the need for manual soil movement and avoiding damage to existing features (i.e. foundation piers, buried plumbing, etc). The greatly reduced weight of the small to medium sized skid steer permits traversing delicate surfaces such as over tree roots, sidewalks, grass or other surfaces. The smaller size of the small to medium skid steer allows it to fit into spaces that the dedicated bull dozers could not fit, for example, inside a pre-existing building or under other low obstructions. Each of these problems is solved by a small to medium sized skid steer vehicle with the capability to be used with an automatic grade control system such as a laser leveling system. 
       FIG. 11  demonstrates an embodiment of the device including, inter alia, a hydraulic  34 , a hydraulic  38 , a guard  41 , a bracket  42 , a frame  44 , a blade  46 , a main arm  48  and a leveler assembly  80 . A portion of the main arm  48  is cut away to show the hydraulic  34  more clearly. 
     If the bracket  42  were not present said hydraulic  34  would be able to move the blade  46  on the pitch axis as demonstrated in  FIGS. 9 and 10 . 
     Said bracket  42 , when attached, acts to prevent hydraulic  34  from any movement and thereby preventing the blade  46  from any pitch movement. Said hydraulic  34  bears the weight of, inter alia, the frame  44 , hydraulic  38 , blade  46  and leveler assembly  80 . This weight exerts substantial pressure on hydraulic  34  even when hydraulic  34  remains at rest. This substantial pressure against hydraulic  34  causes hydraulic  34  to move slightly or have play under the load. Bracket  42  prevents any play of the hydraulic  34  and thereby aids in preventing any bounce of the blade  46  and leveler assembly  80 . 
     Without the bracket  42  the hydraulic  34  has enough play in it to allow the blade  46  to bounce thereby creating an unstable support for the leveler assembly  80 . When the leveler assembly  80  bounces with the blade  46  the leveler assembly  80  cannot properly level the blade  46 . When the skid steer vehicle moves, for example while grading a surface, the blade  46  begins to bounce and the leveler assembly  80  attempts to correct the bounce by adjusting the height of the main arm  48  but this correction frequently leads to an over correction and the blade  46  tends to bounce increasingly more. 
     In the embodiment of the bracket  42  shown in  FIG. 11  the more forward end of the bracket  42  is connected to the frame  44  by welds. However, the more forward end of the bracket  42  could also be removably connected to the frame  44 . The rearward end of the bracket  42  is shown to be removably connected to the main arm  48  by a pin. The pin can be removed to disconnect the bracket  42  from the main arm  48  so that the hydraulic  34  may be free to cause the pitch axis of movement of the blade  46 . 
     Disconnecting the bracket  42  may be useful when attachments other than a dozer blade are attached to the skid steer vehicle. Therefore the full usefulness of the small to medium sized skid steer vehicle is retained because it can be used with any of the attachments including those that benefit from the pitch axis movement. 
     If the skid steer vehicle was made without the hydraulics to effect the pitch axis it may work well with an automatic grade control system but would loose versatility by limiting the available alternative attachments that require the pitch axis, such as a scoop or bucket. 
     Still referring to  FIG. 11 , said guard  41  is optionally present and partially covers the upper end of the bracket  42 . The guard  41  is integral to the main arm  48 . The guard  41  functions as a step and also to prevent human injury if the pin connecting the rearward end of the bracket  42  to the main arm  48  or the bracket  42  should break. 
     The length of the bracket  42  is such that when the bottom of the blade  46  is lowered to approximately the plane defined by the bottom edge of the tracks  18  the face of the blade  46  is substantially vertical to aid in the efficient cutting and moving of the soil being graded. 
     It would be appreciated by one commonly skilled in the art that the bottom of the blade  46  is often adjusted and/or calibrated so that the blade  46  would cut the soil slightly below the track height so that when the skid steer vehicle is moving forward the tracks  18  rest on the newly scraped surface. 
       FIG. 12  shows the front end of a small to medium sized skid steer vehicle demonstrating an alternate bracket  45  as well as, inter alia, the guard  41 , the main arm  48  the hydraulic  34 , the hydraulic  38  and the frame  44 . This embodiment is materially similar to that shown in  FIG. 11  and described above except that in  FIG. 11  there is a single bracket  42  where in the embodiment shown in  FIG. 12  there are two brackets  45 . 
     As in the other embodiments, brackets  45  act to prevent any movement, even slight play, in the hydraulic  34  that is responsible for causing the pitch axis motion as demonstrated in  FIGS. 9 &amp; 10 . As described above, the pitch axis of motion is not needed for automatic grade control systems and allowing the hydraulic  34  to have even slight motion from play in the hydraulic the automatic grade control system, such as a laser leveler, will not function efficiently. Any bounce in the dozer blade attachment in front of the skid steer vehicle will necessarily cause the leveler assembly  80  (shown in  FIG. 1 ) to bounce and make increasingly erratic corrections of the main arm  48  and thereby make an uneven grade surface. 
     In the embodiment of the bracket  42  shown in  FIG. 12  the more forward end of the bracket  45  is connected to the frame  44  by welds. However, the more forward end of the bracket  45  could also be removably connected to the frame  44 . The rearward end of the bracket  45  is shown to be removably connected to the main arm  48  by a pin. The pin can be removed to disconnect the bracket  45  from the main arm  48  so that the hydraulic  34  may be free to cause the pitch axis of movement of the blade  46  when the skid steer vehicle is used for other than with an automatic grade control system. 
       FIG. 13  shows another acceptable position of a pair of brackets  47  where they are connected to a more outward position on the main arm  48  and the frame  44 . The bracket  47  prevents any movement of the hydraulic  34  and therefore any of the dozer blade assembly forward of the hydraulic  34 . As in the other embodiments of the present device, the brackets  47  aid in providing a much more stable platform onto which to mount an automatic grade control system. 
     The hydraulics  34  are a significant source or cause of bouncing of a dozer blade attached to the skid steer in part due to the heavy load that the hydraulics  34  carry. The heavy load can force the hydraulics to have some movement which in turn causes the dozer blade to have some bounce when the skid steer vehicle is moving. The brackets  47  provide substantial additional support to the blade assembly  30  (shown in  FIG. 1 ). 
     One commonly skilled in the art will appreciate a small to medium skid steer vehicle as contrasted to a larger dedicated purpose earthmoving vehicle such as a bulldozer. 
     One commonly skilled in the art will appreciate a small to medium skid steer vehicle may have either ground contacting tracks or wheels. In most environments a track style small to medium skid steer vehicle is preferred for its stability, traction and resistance to sinking in softer soils or creating ruts. 
     The foregoing description conveys the best understanding of the objectives and advantages of the present invention. Different embodiments may be made of the inventive concept of this invention. It is to be understood that all matter disclosed herein is to be interpreted merely as illustrative, and not in a limiting sense.