Abstract:
Apparatus and method providing a ground following capability for an unloading ramp on a receiver of a cotton harvester. At least one fluid cylinder is provided including at least one rod extendible for moving the ramp downwardly to an unloading position and retractable for raising the ramp. A valve apparatus is connected between a source of pressurized fluid and the at least one cylinder and is controllably operable by a control for directing pressurized fluid to the at least one cylinder for extending the at least one rod for moving the ramp to the unloading position. The valve apparatus is automatically operable responsive to exertion of a force against at least one of the rods in a direction for retracting the rod, for directing pressurized fluid from the at least one cylinder to allow the rod to be retracted by the force to thereby raise the ramp.

Description:
[0001]     This application claims the benefit of U.S. Provisional Application No. 60/558,275, filed Mar. 30, 2004. 
     
    
     TECHNICAL FIELD  
       [0002]     This invention relates generally to apparatus and a method providing a ground following feature for an unloading ramp for a cotton harvester, and more particularly, to apparatus and a method which provides the ground following feature while still providing a holding capability for uncommanded movement.  
       BACKGROUND ART  
       [0003]     It is a desirable feature of a cotton harvesting machine to have a ramp which can be extended at an incline from a cotton receiver or holding apparatus on the harvesting machine, such as a basket, packager or module builder, to the ground or another surface onto which the harvested cotton is to be unloaded. Such an unloading ramp preferably has one or more sections pivotable or foldable between an upstanding closed position in covering relation to the open end of the cotton receiver, and an open position extending from the open end of the receiver to the ground or other surface onto which the cotton is to be unloaded. Movement of the ramp between the closed and open positions is typically accomplished using one or more fluid cylinders which are typically extended to move the ramp to the open position. The end of the ramp opposite the cotton receiver is typically supported on the ground or other surface on a plurality of skids, rollers or wheels to facilitate movement thereof over the ground or other surface. A compacted body or module of cotton can weigh several thousand pounds. Therefore, to smoothly unload the compacted cotton onto the ground or other surface, the cotton harvesting machine and ramp are typically moved at a slow speed in a forward direction as the cotton makes the transition onto the ground. This presents a problem when the end of the ramp and/or the machine must pass over obstacles and/or irregularities on the ground, such as a rock, bump, or the like, as any upward movement of the end of the ramp, particularly when supporting several thousand pounds of cotton, can cause damage to the ramp and/or the fluid cylinder or cylinders.  
         [0004]     Accordingly, what is sought is a method and apparatus for providing a ground following capability for an unloading ramp for a cotton harvester which overcomes one or more of the problems set forth above.  
       SUMMARY OF THE INVENTION  
       [0005]     According to a preferred aspect of the invention, apparatus and a method for providing a hydraulically produced ground following capability of an unloading ramp for a cotton harvesting machine which overcomes one or more of the problems set forth above, is disclosed. The apparatus and method are adapted for use with one or more double acting fluid or hydraulic cylinders operable for pivotally moving the unloading ramp between a closed position in covering relation to an open end of a cotton receiving basket, compacting chamber, packager or module builder of the cotton harvesting machine, and an open position oriented at an incline extending downwardly from the open end to the ground or another surface onto which the cotton from the receiver is to be unloaded. With the ramp in the open position, as the cotton is being unloaded and the machine is moving forward, with one or more skids, rollers or wheels supporting a free end of the ramp on the ground or other surface, and moving over varying contours, obstacles and/or imperfections in the surface, the present invention will allow the one or more cylinders to retract and extend as required, such that damage to the cylinder or cylinders and/or the ramp is avoided. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a simplified side view of a representative cotton harvesting machine including a cotton receiver shown tilted to an inclined unloading position and an unloading ramp thereof in an open position;  
         [0007]      FIG. 2  is a simplified fragmentary side view of the machine of  FIG. 1 , showing unloading of a compacted body of cotton onto the ground;  
         [0008]      FIG. 3  is another fragmentary side view of the machine of  FIG. 1 , showing the unloading of the cotton onto the ground as the unloading ramp passes over a rock;  
         [0009]      FIG. 4  is another fragmentary side view of the machine showing a rear wheel thereof passing over a depression in the ground;  
         [0010]      FIG. 5  is another simplified side view of the machine showing a front wheel thereof passing over a bump on the ground;  
         [0011]      FIG. 6  is a schematic representation of apparatus according to the invention;  
         [0012]      FIG. 7  is another schematic representation of the apparatus of the invention; and  
         [0013]      FIG. 8  is still another schematic representation of the apparatus of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]     Referring now to the drawings, in  FIG. 1 , a representative cotton harvesting machine  10  is shown including an unloading ramp  12  shown pivoted to an unloading or open position extending rearwardly from an open end  14  of a cotton receiver  16  of machine  10 , downwardly to a ground surface  18 . Cotton receiver  16  is representative of a wide variety of receivers such as a basket, a cotton compactor, a packager, or a module builder, and is shown supported at an unloading incline by a fluid cylinder  20 . Unloading ramp  12  in its unloading position forms a substantially planar continuation of a floor  22  of receiver  16 . Ramp  12  is preferably pivotally connected to receiver  16  by a pivotal connection  42 , and is pivoted and unfolded to the open unloading position shown and is held in that position by four fluid cylinders, including a pair of first cylinders  24  connected between cotton receiver  16  and a first ramp segment  26 , and a pair of second cylinders  28  in a slave relationship to first cylinders  24  and connected between first ramp segment  26  and a second ramp segment  30 . First and second cylinders  24  and  28  are operable in concert for pivoting and holding first and second ramp segments  26  and  30  in overlaying or covering relation to open end  14  of cotton receiver  16 .  
         [0015]     When unloading ramp  12  is in the fully open position as shown, rods  32  of first cylinders  24  will extend therefrom a distance A, and rods  34  of second cylinders  28  will extend a distance B therefrom. The end of second ramp segment  30  is supported on ground surface  18  for movement therealong by wheels  36 . Here, it should be noted that it is desirable for cylinders  24  and  28  to have the capability for holding ramp  12  substantially fixedly or rigidly in the unloading position as shown, to allow passage of a compacted body of cotton thereover between cotton receiver  16  and ground surface  18  without significant sagging or buckling. It is also desirable for cylinders  24  and  28  to have the capability to allow ramp  12  to have a ground following capability so as to pivot relative to cotton receiver  16  sufficiently to pass over obstacles such as bumps, rocks, logs, depressions, small ditches, and the like, without placing potentially damaging loads and stresses on the cylinders and ramp  12 , as machine  10  is moved over the ground in the forward direction during the unloading operation.  
         [0016]     Referring also to  FIG. 2 , cotton harvesting machine  10  is again shown with unloading ramp  12  in its unloading or open position relative to open end  14  of cotton receiver  16 , which is tilted in its unloading position. A compacted body of cotton  38  is shown being unloaded from ramp  12  onto ground  18  as machine is moved in the forward direction, as denoted by arrow C. Wheel  36  is shown approaching a rock  40  on ground surface  18 .  
         [0017]     Referring also to  FIG. 3 , machine  10  is moved such that wheel  36  of unloading ramp  12  is shown atop rock  40 , and ramp  12  is shown pivoted in the direction D about pivotal connection  42  relative to cotton receiver  16  as machine  10  continues to move in direction C during the unloading. As will be explained, the movement of ramp  12  in direction D about pivot  42  is allowed by automatic retraction of rod  32  into cylinder  24  by an amount X, as denoted by the distance A-X as a result of the ground following capability according to the invention.  
         [0018]     Referring also to  FIG. 4 , a rear wheel  44  of machine  10  is shown in a depression  46  in ground surface  18 , and to reduce harmful loads and stresses on ramp  12 , ramp  12  is again allowed to pivot as denoted by arrow D about connection  42  by the retraction of rod  32  into cylinder  24  by an amount Y, as shown by distance A-Y, as allowed by the apparatus of the present invention.  
         [0019]      FIG. 5  shows retraction of rod  32  into cylinder  24  by the amount Z, as shown by distance A-Z to allow pivotal movement of ramp  12  relative to receiver  16  as a front wheel  50  moves over a mound  48 , again as allowed by apparatus of the present invention.  
         [0020]     Also referring to  FIG. 6 , apparatus  52  for controlling extension and retraction of rods  32  of first cylinders  24  and rods  34  of second cylinders  28  for pivotally moving ramp  12  between its closed and open unloading positions, is shown. Apparatus  52  is also operable according to the present invention for providing an automatic ground following capability for relative pivotal movement of machine  10  and ramp  12  about pivotal connection  42  for movement over obstacles and irregularities such as rock  40 , depression  46  and mound  48 , without undesirably loading and stressing ramp  12  and the components thereof, including cylinders  24  and  28 . Apparatus  52  includes a pair of directional control valves  54  and  56  which are preferably three-way valves, such as commercial available spool valves or the like, each having a port connected by a fluid line  58  to a source of pressurized fluid such as a conventional fluid pump (not shown) on machine  10  in the well known manner. Valves  54  and  56  also include a port connected by a fluid line  60  to a tank or reservoir (also not shown) on machine  10  in the conventional manner. The third ports of valves  54  and  56  are connected to ports of counterbalance valves  62  and  64 , by fluid lines  66  and  68 , respectively. Directional control valves  54  and  56  are controlled by a pilot control valve  70  connected to respective valves  54  and  56  by pilot control lines  72  and  74 . Pilot control valve  70 , in turn, is operator controllable for selectably delivering pressurized fluid through pilot control lines  72  and  74  to valves  54  and  56 , respectively, for delivering pressurized fluid through counterbalance valves  62  and  64  to cylinders  24  and  28 , for effecting pivotal movement of ramp  12 , as will be discussed hereinbelow.  
         [0021]     Counterbalance valves  62  and  64  are preferably each a two-way pilot controlled pressure relief valve having pilot signal ports connected to fluid lines  68  and  66 , respectively, by pilot control lines  76  and  78 . The second port of counterbalance valve  62  is connected by a fluid line  80  to head end ports of cylinders  24 . The second port of counterbalance valve  64  is connected by a fluid line  82  to rod end ports of cylinders  28 . A check valve  84  is connected between lines  66  and  80  to allow fluid flow around counterbalance valve  62  in the direction toward cylinders  24 . Similarly, a check valve  86  connects lines  68  and  82  to allow fluid flow around valve  64  to cylinders  28 . Rod end ports of cylinders  24  are connected by lines  88  to head end ports of cylinders  28 . Check valves  90  are disposed between line  80  and an intermediate port of cylinders  24 , to allow fluid flow from the cylinders. Check valves  92  are disposed between lines  88  and additional intermediate ports of cylinders  24  to allow flow from the cylinders. Check valves  94  are disposed between lines  88  and intermediate ports on cylinders  28  to allow flow from the cylinders, and additional check valves  96  connect lines  82  and intermediate ports on cylinders  28  to allow flow from the cylinders.  
         [0022]     In operation, to move ramp  12  to its unloading or open position, pilot control valve  70  is moved by the operator to its upper position to allow pressurized fluid flow from line  58  through line  72  to directional control valve  54  to move that valve to its upper position. In this mode, pilot control valve  70  connects line  74  to tank via line  60 , such that valve  56  remains in the position shown. Pressurized fluid will then flow from line  58  through valve  54  to line  66 , and through check valve  84  to line  80 , to the head end ports of cylinders  24 . Initially, until sufficient pressure is developed, rods  32  will not be moved, as fluid cannot pass through counterbalance valve  64 , which is closed. However, pressure buildup in line  66  will be communicated to valve  64  via line  78  to move that valve to its open position when its pilot pressure is reached. This will allow fluid flow through valve  64  from line  82  to line  68 . Pressurized fluid can now flow through the head end ports of cylinders  24  to extend rods  32 , as denoted by arrow E, and the fluid from the rod ends of those cylinders will flow through lines  88  into the head end ports of cylinders  28 , to extend rods  34 , as denoted by arrow E, thereof such that unloading ramp  12  will be fully opened in its unloading position.  
         [0023]     Referring also to  FIG. 7 , apparatus  52  is shown with rods  32  and  34  of fluid cylinders  24  and  28 , respectively, extended by the distances A and B shown in the previous figures, such that ramp  12  is in its open unloading position. With cylinders  24  and  28  extended in this manner, the ground following capability according to the present invention, for reducing loading and stress on the cylinders and also on ramp  12 , will be explained. Essentially, when any of the conditions illustrated in  FIGS. 3, 4  and  5  are encountered, a force will be applied against rods  32 , as denoted by arrows F to urge the rods to retract. Referring briefly back to  FIG. 1 , second ramp segment  40  is pivotable to the position shown in a counterclockwise direction, and hard stops prevent further pivotal movement in that direction. The application of forces F on rods  32  will serve to increase pressure of fluid in the head ends of cylinders  24 , which pressure will be transferred through lines  80  and  98  to valve  62 . The pressure will also be transferred through check valves  92  and lines  88  to the head ends of cylinders  28 , and through check valves  96  and lines  82  and  100  to valve  64 . When the pressure exceeds the pilot pressure of valve  62 , that valve will open to allow fluid flow through line  66  to valve  54  and through that valve and line  60  to tank. This will allow retraction of rods  32  by an appropriate or required distance X, Y or Z, and as rods  32  are displaced in the retracting direction, a vacuum condition is created in the rod ends of cylinders  24  causing check valves  92  to open such that fluid will be transferred from the head ends to the rod ends of those cylinders. The pressure condition in the head ends of cylinders  28  and line  82  will also be reduced. Once the affected wheel or wheels  36 ,  44  and/or  50  has passed the obstacle or depression, rods  32  will still be in the retracted position and wheels  36  will be elevated above the ground, thereby placing the weight of ramp  12  and any cotton thereon on the cylinders to urge them in the direction to extend, opposite the direction F. This will increase the pressure in the rod ends of the cylinders, particularly cylinders  24  which are not fully extended. This pressure will be transferred through lines  88  and the head ends of cylinders  28 , check valves  96  and line  82  to pilot control line  100  of valve  64 . When the pressure exceeds the pilot pressure of that valve, it will open to allow flow through line  68 , valve  56  and line  60  to tank. As rods  32  again extend, a vacuum condition in the head ends of cylinders  24  will exist, which will be communicated through line  80  to check valve  84  which will open to allow oil flow into the head end of the cylinders. When the pressure condition is alleviated, valve  64  will close and the vacuum condition on check valve  84  will dissipate.  
         [0024]     Referring also to  FIG. 8 , operation of apparatus  52  for retracting rods  32  and  34 , as denoted by arrow G, of cylinders  24  and  28  for pivoting and folding ramp  12  to its closed position, will now be explained. In this operation, valve  70  is moved to its lower position to allow pressurized fluid from line  58  to pass through pilot control line  74  to valve  56  to move it to its lower position. Valve  54  will remain in the position shown. This will result in pressurized fluid moving through valve  56  and line  68  to check valve  86  and through that valve to line  82 , bypassing valve  64 . The pressurized fluid will then enter the rod ends of cylinders  28  and will build pressure. This pressure will be transferred through lines  88  to the rod ends of cylinders  24  to apply pressure against the fluid in the head ends thereof, which will increase pressure in lines  80  and  98  connected to valve  62 . When the pressure in line  98  exceeds the pilot pressure of valve  62 , that valve will open to allow escape of fluid from the head ends of cylinders  24 . This will allow movement of fluid into the rod ends of those cylinders, such that rods  32  can retract and as that occurs, rods  34  will retract into cylinders  28 , to thereby fold the ramp. Once the ramp is in its folded or closed position, valve  70  can then be returned to its neutral or middle position. With the ramp in this position, the cylinders are now held or locked in place because both pilot operated relief valves and both check valves associated therewith are closed thereby preventing fluid flow out of either end of the cylinders as long as cylinder pressure does not exceed the pressure relief pressures.  
         [0025]     It will be understood that changes in the details, materials, steps, and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.