Abstract:
An agricultural implement having agricultural implement for supporting a plurality of gangs of disk blades extending generally laterally relative to a for travel direction. The implement has carrier frames pivotally connected to wheel assemblies for controlling the height of the carrier frames relative to the ground through hydraulic actuators acting on the wheel assemblies. A hydraulic control unit enables independent and individual control of each actuator through the use of three way valves that selectively connect or lock individual actuators.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a divisional of U.S. Ser. No. 14/558.498, filed Dec. 2, 2014, which claims benefit from U.S. provisional patent application Ser. No. 61/914,529, filed Dec. 11, 2013. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to farm implements, and, more particularly, to systems and methods for maintaining such implements level relative to the soil. 
         [0004]    2. Description of the Related Art 
         [0005]    In the continuing quest for providing greater efficiency in the operation of farm implements, machines have been constructed to have ever increasing lateral spans relative to a tractor or central unit propelling the unit over a field. When the span increases to realize greater efficiency and speed, the criteria of having a uniform and level tool contact with the soil becomes extremely critical. Equipment with significant lateral spans have many different joints and are usually articulated to enable transport to and between fields. 
         [0006]    An area of special importance to level positioning of farm implements is found in the tillage field. The desirable outcome is a uniform physical depth of the tillage and a uniform entry of the disk blades or harrows into the soil. The need to have a level positioning of the implement is made more challenging with the use of hydraulic actuators which control the depth of penetration of the disk blades or other tools. In current practice, hydraulic actuators axe connected in series and it is possible through normal operation for hydraulic fluid leakage to make the actuators out of sync with one another. In addition, field conditions, such as wheel loading and other variables, require an adjustment to the synchronization of the different sections of the tillage implement, thereby requiring the operator to dismount from a tractor and make manual adjustments. 
         [0007]    It is current practice to partially counter this occurrence by fully elevating the implement to the point where bypass lands in the actuators allow full flow of hydraulic fluid to pass through the actuators and again synchronize the multiple units. However, this adds an additional step to the operation, particularly in the field. thereby decreasing the efficiency and speed with which the particular task is accomplished. 
         [0008]    What is needed in the art therefore, is, an efficient apparatus and method for maintaining agricultural implements in a level position relative to the soil. 
       SUMMARY OF THE INVENTION 
       [0009]    An advantage of the present invention is a more accurate and efficient synchronization of multiple sections of a farm implement. 
         [0010]    In one form, the invention is an agricultural implement spanning a lateral distance relative to a forward direction. The implement has a plurality of interconnected carrier frames, each for supporting a plurality of soil engaging tools. At least one supporting element is carried by each carrier frame for variably positioning the carrier frame relative to the soil. An actuator has a base and a variably extending elongated element connected between each supporting element and the respective carrier frame for varying the position of the respective carrier frame relative to the soil. A sensor determines the displacement of the elongated clement relative to the base of each of the actuators. An actuator control unit is provided for each actuator to move the actuator independently in response to a signal input. An electronic control unit “ECU” receives a desired input signal and compares it to the signal from the sensor to send a resulting signal to the actuator control unit for varying, the position of each elongated element to reach the desired signal input for the system. 
         [0011]    In another form, the invention is a method of leveling an agricultural implement relative to the soil with the agricultural implement including a plurality of articulated carrier frames, each for supporting a plurality of soil engaging tools and having at least one supporting element carried by the carrier frame for variably positioning the carrier frame relative to the soil. An actuator is provided for each supporting element with the actuator having a base and variably elongated element connected between the supporting elements and the carrier frame for setting the position of the carrier frame relative to the soil. The method includes the steps of determining a set point for displacement of each carrier frame relative to the soil at the respective supporting element, individually determining the displacement of the elongated element relative to the base of the sensor and comparing the set point and the actual displacement of the actuator to apply individually a correcting signal to level the carrier frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0013]      FIG. 1  illustrates a tillage implement including a support of disk blades embodying the present invention, being pulled by a tractor shown in schematic fashion; 
           [0014]      FIG. 2  is a plan view of a hydraulic system shown in the prior art for the tillage implement of  FIG. 1 ; 
           [0015]      FIG. 3  is a plan view of a hydraulic system for the tillage implement of  FIG. 1 ; 
           [0016]      FIG. 4  is a plan view of a preferred hydraulic system for the tillage implement of  FIG. 1  in a first state; and 
           [0017]      FIGS. 5-9  show the hydraulic system of  FIG. 4  in different states; and 
           [0018]      FIG. 10  is a perspective view, illustrating the frame sections, some of the supporting elements, the actuators, and the sensors of the present invention. 
       
    
    
       [0019]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates an embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a tillage apparatus  10  which generally includes a tractor  12  shown schematically and an agricultural tillage implement  14  for tilling the soil prior to seeding. It should be noted that many different tools may be employed with the tillage implement  14  beyond the embodiment shown. 
         [0021]    Agricultural tillage implement  14  is configured as a multi-section field disk ripper  14 , and includes a carriage frame assembly  16 . Carriage frame assembly  16  is the section that is directly towed by a traction unit, such as agricultural tractor  12 . Carriage frame assembly  16  includes a pull hitch  18  generally extending in a travel direction  20 , and forward and aft oriented carrier frame, members  22  which are coupled with and extend from pull hitch  18 . Reinforcing gusset plates  24  may be used to strengthen the connection between pull hitch  18  and carrier frame members  22 . 
         [0022]    The tillage implement  14  has a center section  26 , an inner right wing section  28  and an outer right wing section  32  as viewed in  FIG. 1  and  FIG. 5 . A left inner wing section  30  connects with a left outer wing section  34 . The center section  26  is pivotally connected to the inner wings  28  and  30  by pivotal interconnections at  36 . The right inner wing section  28  and right outer wing section  32  are pivotally interconnected at  38 . The left inner wing section  30  and outer left wing section  34  are interconnected at pivotal joints  40 . The details of the pivotal joints are omitted to enable a clearer understanding of the present invention. However, it should be understood that the pivotal connections allow articulation of the various sections between a field position in which each of the sections are substantially in a common plane and a transport position in which the outer wing sections  32  and  34  are folded, as well as the inner wing sections  28  and  30 , to enable sufficient road clearance. 
         [0023]    Actuator assemblies  42  are connected between the center section  26  and inner wing sections  28  and  30  to enable pivoting between the field and transport position. Actuator assemblies  44  arc interconnected between right inner wing section  28  and outer right wing section  32  as well as inner left wing section  30  and outer wing section  34  to enable the pivoting movement. 
         [0024]    The center section  26  has a forward frame member  46  extending across carrier frames  22  and secured thereto. Center section  26  additionally has an aft frame member  48  structurally interconnected with carrier frames  22  at their aft end. As is noted, the frame elements  46  and  48  extend generally laterally with respect to the direction of movement  20  of the agricultural implement. Frame members  46  and  48 , however, extend at an angle as is known in the tillage art to produce appropriate working of the soil. The frame members  46  and  48  provide support beneath them for gangs of disc blades  50 . The gangs of disc blades  50  are resiliently connected to the frame elements in appropriate fashion to provide smooth working of the soil. 
         [0025]    The inner wing sections  28  and  30  each have a forward frame member  52  and an aft frame member  54 . These frame members are interconnected by forward and aft oriented inner frame members  56  and outer frame members  58 . The forward and aft frame members  52  and  54  form an extension of forward and aft frame members  46  and  48 . The forward and aft frame members  52  and  54  each also support gangs of disc blades  50 . 
         [0026]    The outer wing sections  32  and  34  each have forward and aft frame members  60  and  62  which each support gangs of disk blades  50 . Frame members  60  and  62  are interconnected by inner frame members  64  and outer frame members  66 . 
         [0027]    As illustrated in  FIGS. 1 and 5 , the various sections  26 ,  28 ,  30 ,  32  and  34  of the tillage implement  14  are positioned at variable positions relative to the soil, and thus set the position of the gangs of disk harrows  50  above the soil and the depth they cut into the soil. As illustrated, variable support elements for the sections are shown as wheel sets but it should be understood that other forms of variable support may be employed. As illustrated, wheel sets  68  are pivotally interconnected with carrier frames  22  so that they provide support to the forward and aft frame members  46  and  48  relative to the soil. Wheel sets  70  are interconnected with frame element  58  to support and variably position inner wing sections  28  and  30  relative to the soil. In addition, wheel sets  72  are pivotally mounted on frame members  66  to support and variably position outer wing sections  32  and  34  at a variable distance relative to the soil. Actuators  74  and  76  manipulate wheel sets  68  to establish the distance of center section  26  relative to the soil. Actuators  78  and  80  support and variably position sections  28  and  32  relative to the soil. Finally, actuator assemblies  82  and  84  support and variably position sections  30  and  34  relative to the soil. 
         [0028]    In addition, castor wheel assemblies  86  on section  32  and  88  on section  34  orient the for and aft angle of the tillage implement  14  relative to the soil. Actuators  90  and  92  are employed for this purpose. 
         [0029]    The actuators described above are shown as hydraulic and for this purpose a hydraulic control unit  94  is mounted in the tractor  12  and has a pump  100  for pressurizing hydraulic fluid to control the actuators. The hydraulic control unit  94  receives inputs from an electronic control unit (ECU)  96  which receives various inputs set out below, in addition to an operator input through control unit  98 . 
         [0030]    The hydraulic interconnection established by a typical prior art system for elevating the various sections of the tillage implement  14  is shown in  FIG. 2 . In this arrangement, each of a set of actuators  102   a,    104   a,    106   a  and  108   a  is connected to a hydraulic control pressure source by supply conduits  110   a  and  112   a.  As is illustrated in  FIG. 1  the actuators  102   a - 108   a  are connected in parallel so that the pressure uniformly applies to each actuator in the set. As described above however, the actuators may become out of sync due to linkage past a piston thus requiring additional steps in the field to ensure synchronization of the actuators. 
         [0031]    In accordance with the present invention, a control system and method set forth in  FIG. 3  overcomes these difficulties.  FIG. 3  shows actuators  74 ,  76 ,  78  and  80 . The operation of the additional actuators is similar and is omitted to enable a better understanding of the present invention. Each of the actuators  74 ,  76 ,  78  and  80  has an output shaft  75 ,  77 ,  79  and  81 , respectively extending from the actuator body. Each actuator has a piston displaceable within a chamber in the actuator body and connected to the respective output shaft. 
         [0032]    The piston end of the actuator  74  is connected to the hydraulic control unit  94  by a hydraulic line  102 . The output shaft end of actuator  74  is connected to the hydraulic control unit  94  by a return line  104 . In similar fashion, the piston end of actuator  76  is connected by line  106  and a return line  108  is provided to control unit  94 . The piston end of actuator  78  is connected to hydraulic control unit  94  by line  110  and the return line is designated as  112 . Finally, the piston end of actuator  80  is connected to hydraulic control unit  94  via hydraulic line  114  and a return line  116  is provided. The independent connection of the actuators to the hydraulic control unit  94  will enable independent establishment of the height of the units relative to the soil. 
         [0033]    The relative physical position of the hydraulic control unit  94  may be different than the one shown in  FIG. 3 , depending up on the application for the unit. It may be a single module or may be provided in individual control sections with at least several of the hydraulic actuators connected hydraulically in series. However the hydraulic control unit  94  is positioned relative to the actuators, it permits independent manipulation of the actuator output shafts as will be described below. 
         [0034]    For this purpose, a displacement detecting device is provided to provide a signal proportional to the displacement of each output shaft relative to the body of the respective actuator. Alternatively, a displacement detecting device may be employed to provide a signal reflecting the position of the carrier frame relative to the soil at the frame supports. In addition to the displacement signal, a signal reflecting the rate of change of displacement or ΔD/Δ T is provided. As shown in  FIG. 3 , the displacement indicating devices are identified as  118  for actuators  74 ,  120  for actuators  76 ,  122  for actuator  78  and  124  for actuator  80 . As illustrated in  FIG. 10 , those actuators  74 ,  76 ,  78  and  80  and their respective displacement devices  118 ,  120 ,  122  and  124  are shown. In addition the displacement indicating devices are identified as  121  for actuator  82  and  123  for actuator  84 . The displacement indicating devices  118 ,  120 ,  122  and  124  provide signal inputs to the ECU via lines  126 ,  128 ,  130  and  132 , respectively. Similarly, it will be understood that displacement indicating devices  121  and  123  also will provide signal inputs to the ECU via lines (not shown). The displacement indicating devices are devices that provide appropriate control signals that are proportional to the displacement of the output shaft relative to the various actuators and preferably the rate of change of displacement. The interconnections with the output shafts and actuators are not included to enable a better focus on the basic principle of the invention. Any one of a number of sensors may be employed for this purpose. 
         [0035]    As shown in  FIGS. 3 and 10 , the displacement sensors and ΔD/Δ T sensors are incorporated into a single unit. However, the ΔD/Δ T signal may be provided in a separate unit  119  shown in dashed lines for actuator  74 . Unit  119  may be connected to ECU  96  by a line  127 , also shown as a dashed line. Similar units would be provided for actuators  76 ,  78 ,  80 ,  82 , and  84  if it is desired to use separate units for displacement and ΔD/Δ T signals. 
         [0036]    Referring to  FIG. 4 , the invention is applied to the tillage implement of  FIG. 1  by initially setting the implement on a level surface for calibration. The implement  14  is raised to the maximum extent where each individual actuator has its, output shaft at its maximum length. At this point, a bypass port in the piston provides a bypass for return flow back to the actuator control unit  94 . This ensures that any air entrained in the system due to assembly or other reason is passed to the hydraulic system. The implement  14  is then lowered so that the tools, in this case the gangs of disk blades  50 , just touch the level surface. Preferably this surface would be a level concrete surface. Once the actuators are adjusted to reach this point, individual readings of the displacement between the actuator rod and the actuator body are taken with full hydraulic fluid in the chambers. The displacement signals of the individual actuators are stored in the ECU  96 . The resultant individual actuator displacement signals are considered the synchronized set point for the signals. It should be apparent to those skilled in the art that the use of placing the tools at the plane of the soil is but one of a number of reference points that define a unitary plane used in defining the reference plane. 
         [0037]    The tillage implement is then in a position to have each of the actuators raise and lower the individual frame elements in unison to provide a uniform height above the ground and a uniform depth when the gangs of disk blades  50  are positioned in the soil. Periodically during the operation of the tillage implement, the readings of the individual actuators are determined and, if they deviate from the set point initially established, the hydraulic control system provides appropriate hydraulic fluid to achieve the same set point. This is done independently of the other actuators so that correction is applied individually to each actuator unit. The tillage implement  14  is then able to provide accurate depth of penetration among the gangs of disk harrows  50 . 
         [0038]    The implement may be adjusted additionally in the field. In this procedure, the operator prepares a test run into the soil in a field and then measures the depth of the penetration of the disk blades. To the extent that it is necessary to make a minor adjustment, the individual cylinder that is out of sync with the remaining cylinders is adjusted and a new set point is established as the level uniform plane. This ensures that field conditions such as wheel loading and other factors have a minimal and easily correctable impact on the tillage operation. 
         [0039]    In addition, the actuators are corrected for the differential rate of displacement change by the ΔD/Δ T so that the entry of the gangs of disk blades  50  is uniform at the beginning of the field and the withdrawal is uniform at the end of the field. The process of recalibration may be made automatic so that it does not interfere with the immediate operator directed tillage over a field and preparing the soil. 
         [0040]    While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.