Abstract:
A method and apparatus for automating some of the tasks that heretofore required operator action at headland turns or similar events are provided. The present invention automates operation of lift assist wheels and/or gull wings, such as those found on a stack-fold implement, based on the position of the tractor hitch to which the implement is coupled. An operator may control the position of the implement, such as at a headland turn, by raising and lowering the tractor hitch using a remote control. The invention enables the planter to compare the tractor hitch position relative to an implement position and control operation of the implement accordingly without additional user inputs.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a divisional of application Ser. No. 13/248,798 filed Sep. 29, 2011. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is generally directed to farm implements and, more particularly, to a method and apparatus for maintaining a level orientation of a bulk fill hopper frame. 
     Increasingly farm implements have been designed to have frames that can be folded between field-working and transport positions. One such type of farm implement is a stack-fold planter, such as the 1230 Stackerbar planter from Case New Holland, LLC. Stack-fold planters generally consist of a center frame section and a pair of wing frame sections. In the field-working position, the wing frame sections are evenly aligned with the center frame section. In the transport position, however, the wing sections are lifted to a position directly above the center frame section, i.e., to “stacked” position, in the stacked position, the width of the implement is generally that of the center frame section, thus making the implement better suited for transport along roads and between crops. 
     Openers are mounted to the frame sections at equal intervals, with each of the wing sections typically carrying one-half the number of openers mounted to the center frame section. The openers are designed to a cut a furrow into a planting surface, deposit seed and/or fertilizer into the furrow, and then pack the furrow. In this regard, each opener will have a seed box that is manually loaded with seed and/or fertilizer. Since the size of the seed box determines how much particulate matter the box can retain, there is generally a desire to have larger seed boxes for each of the openers. Since the larger seed boxes can hold more material, fewer refilling stops are needed when planting a field. 
     Larger seed boxes, however, have drawbacks. The additional material that can be carried by larger seed boxes adds to the overall weight of the openers, including those mounted to the wing sections. This additional weight can stress the lifting/lowering system that stacks the wing sections, or require a more robust system, which can add to the overall size, mass, complexity, and cost of the implement. Larger spacing between seed trenches lower per acre crop yields. Further, it can be problematic and time consuming to individually fill each of the seed boxes, whether using bags or a conveyor system. 
     Accordingly, bulk fill systems have been designed for stack-fold planters that generally consist of one or more bulk fill tanks mounted to a frame or toolbar that can be coupled to the frame of the stack-fold planter. The frame for the bulk fill system is supported above the ground by a lift wheel assembly that is designed to raise the frame when the stack-fold planter is in transport. Oftentimes, an operator will also raise the bulk fill system frame at headland turns when the gull wings are also raised to provide additional implement stability. 
     Raising the gull wings and the frame for the bulk fill hopper(s) at headland turns poses one of the challenges that is faced by an operator when making a headland turn onto a new swath. More particularly, as the operator of a planter arrives at the headland of a field, the operator has to perform numerous tasks to reposition the planter in the next swath. Many of these tasks require the operator to attempt simultaneous control of three or more operations. For stack-fold planters equipped with lift assist wheels and/or gull wings, the operator needs to retract the gull wings to prevent the wings from drooping when lifted from the ground, elevate the three-point hitch that connects the stack-fold planter to the towing vehicle, e.g., tractor, and extend the lift wheel assembly to raise the bulk fill system. The operator will also need to slow the tractor by shifting and/or reducing engine speed. By requiring the operator to perform these tasks substantially simultaneously, the operator can become mentally and physically fatigued, require an enhanced skill level to operate the stack-fold planter, increase the likelihood that the operator may make an error, or reduce the performance of the stack-fold planter at headland turns. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a method and apparatus for automating some of the tasks that heretofore required operator action at headland turns or similar events. For example, in one embodiment, the present invention automates operation of lift assist wheels and/or gull wings, such as those found on a stack-fold implement, based on the position of the tractor hitch to which the implement is coupled. Accordingly, an operator may control the position of the implement, such as at a headland turn, by raising and lowering the tractor hitch using a conventional remote control. The invention enables the planter to compare the tractor hitch position relative to an implement position and control operation of the implement accordingly without additional user inputs. 
     In accordance with one aspect of the invention, a farm implement has a toolbar configured to be coupled to a towing vehicle and a bulk fill hopper mounted to a frame that is supported by a lift wheel assembly. The farm implement further has a connector for coupling the toolbar to a hitch of the towing vehicle. A first electrical input receives a hitch position signal from the towing vehicle and a second electrical input receives a frame position signal. The implement further has an electronic control unit (ECU) that receives the hitch position and the frame position signals and automatically activates the lift wheel assembly to maintain the frame in a level position as the vertical position of the connector changes. 
     In accordance with another aspect of the invention, a farm implement having a frame supported by a lift wheel assembly comprises a connector for coupling the toolbar to the ISOBUS hitch of a towing vehicle, a first electrical input that receives a hitch position signal from the tractor, an electric over hydraulic valve that controls hydraulic fluid flow from the hydraulic system to the lift wheel assembly, and an electronic control unit (ECU). The ECU receives the hitch position signal and provides a command signal to the electric over hydraulic valve to control hydraulic fluid flow in the hydraulic system to raise the frame when the hitch is in a raised position. 
     The present invention is also embodied in a method for automatically leveling a farm implement having a frame and being towed by a tractor that is coupled to the farm implement by a hitch. The method, which is preferably carried out automatically using various electronics, includes receiving a hitch position signal from the tractor and receiving a frame position signal from a sensor that detects a position of the frame. The method further includes the step of automatically raising or lowering the frame in response to changes in hitch position of the tractor. 
     Other objects, features, aspects, and advantages of the invention will become apparent to those skilled in the art from the following detailed description, and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. 
       In the drawings: 
         FIG. 1  is a pictorial view of an agricultural planting system comprised of a stack-fold planter coupled to a tractor; 
         FIG. 2  is an isometric view of the stack-fold planter of  FIG. 1  in a field-working (float) position; 
         FIG. 3  is a rear elevation view of the stack-fold planter of  FIG. 1  in a stacked, transport position; 
         FIG. 4  is an isometric view of the central bulk fill system of  FIG. 1  in a lowered, field working position; 
         FIG. 5  is a schematic block diagram of a hydraulic control system according to one embodiment of the invention; and 
         FIG. 6  is a schematic block diagram of a hydraulic control system according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     As will be made apparent from the following description, the present invention provides an apparatus that automatically adjusts the position of an implement in response to changes in the position of the hitch of a tractor towing the implement. For purposes of description, the invention will be described with respect to a stack-fold planter, such as that shown in  FIGS. 1-4 , but it is understood that the invention is applicable with other types of implements. The invention, which can also be embodied in an automated method, is designed to reduce the number of user inputs that were heretofore required to command movements of the implement, such as at headland turns. 
     Turning now to  FIGS. 1-4 , a planting system  10  includes a stack-fold implement  12 , shown in a field working position, coupled to a prime mover  14 , e.g., tractor, in a known manner. For purposes of illustration, the stack-fold implement  12  is a row crop planter, which as shown in  FIG. 2 , includes a frame  16  generally comprised of a center section  18  and wing sections  20 ,  22  on opposite lateral sides of the center section. The center section  18  includes a tongue (not shown) that extends forwardly of the center section  18  for hitching the implement  12  to the prime mover  14 . As will be described more fully below, the implement  12  is coupled to a three-point hitch of the prime mover  14 . Gauge wheels  24  on the frame sections  18 ,  20 , and  22  set the seeding or cutting depth for the implement. 
     In the illustrated embodiment, sixteen openers  26  are mounted to the frame  16  at equally spaced intervals, but it is understood that more than or fewer than sixteen openers could be mounted to the frame  16 . As known in the art, the wing sections  20 ,  22  may be raised to a transport position, as shown in  FIG. 3 , in which the openers carried by the wing sections  20 ,  22  are stacked over the center section  18 . As also known in the art, the openers  26  are designed to cut a furrow into the soil, deposit seed and/or fertilizer into the furrow, and then pack the furrow. Seed boxes or “mini-hoppers”  28  are optionally mounted to each of the openers  26 . The mini-hoppers  28  are preferably smaller than conventional mini-hoppers used with stack-fold crop row planters and thus hold less material than conventional seed boxes. 
     The smaller mini-hoppers are flow-coupled to a central bulk fill assembly  30  that delivers material, such as seed and/or fertilizer, to the openers  26  and/or the mini-hoppers  28 . The central bulk fill assembly  30  preferably includes a pair of bulk fill hoppers  32  and  34  supported adjacently to one another on a frame  36 . The frame  36  is coupled to the center section  18  by a set of rearwardly extending frame members  38 ,  40 , and  42  connected to a crossbar  44 . In a preferred embodiment, the frame members  38 ,  40 ,  42  are removably coupled to center frame section  18  which allows the bulk fill assembly  30  to be removed from the implement  12  or added as an after-market add-on to an existing stack-fold implement. 
     The frame  36  is supported above the work surface (or transport surface) by a pair of wheels  46 ,  48  that are each connected to the frame by a wheel lift assembly  50 , which in the illustrated embodiment includes a pair of parallel linkages  52 ,  54 . Each linkage includes upper links  56 ,  58  and lower link  60 ,  62 , respectively. In addition to the links  56 - 62 , a pair of lift arms  64 ,  66  are provided. Lift arm  64  is coupled to frame member  42  at a knuckle  68  to which parallel linkage  52  is also connected. In a similar manner, lift arm  66  is coupled to frame member  38  at a knuckle  70  to which parallel linkage  54  is also connected. As shown particularly in  FIG. 4 , the frame  36  further includes a Y-beam  72  that is pivotally coupled to the center frame member  40 . As is customary for most central bulk fill assemblies, an air blower  74  is mounted beneath the bulk fill hoppers and is operable transfer particulate matter from the hoppers  32 ,  34  to the individual mini-hoppers  28  or directly to the openers  26  in a forced air stream. 
     As known in the art, central bulk fill hoppers, such as those described above, provide the convenience of a central fill location rather than having to fill the individual seed boxes. Also, the central fill hoppers have greater capacity than the seed boxes, which reduces the number of fill iterations that must be taken when planting. Simply mounting a central bulk fill assembly to a stack-fold planter, such as planter  12 , can create stability issues, especially when the stack-fold planter is in the transport position. In this regard, the present invention provides a mechanism for raising the bulk fill assembly  30  when the stack-fold planter  10  is in the folded, transport position. Raising the bulk assembly  30  provides greater stability during transport as well provides increased clearance between the bulk fill assembly  30  and the roadway. 
     A pair of hydraulic lift cylinders  76  and  78  are operable for lifting the frame  36 , and thus the bulk fill assembly  30 . Cylinder  76  is interconnected between forward knuckle  68  and a rearward knuckle  80 . As shown in  FIG. 4 , the rearward knuckle  74  includes, or is coupled to, a mounting arm  82  that is coupled to axle  84  about which wheel  46  rotates. Cylinder  76  includes a ram  86  that is coupled to the rearward knuckle  80  whereas cylinder  76  is coupled to the forward knuckle  68 . In a similar fashion, cylinder  78  includes a ram  88  connected to a rearward knuckle  90  whereas the cylinder  78  is connected to the forward knuckle  70 . It will be appreciated that a mounting arm  92  is connected to, or formed with, the rearward knuckle  90 , and the mounting arm  92  is connected to an axle (not shown) about which wheel  48  rotates. 
     As known in the art, central bulk fill hoppers, such as those described above, provide the convenience of a central fill location rather than having to fill the individual seed boxes. Also, the central fill hoppers have greater capacity than the seed boxes, which reduces the number of fill iterations that must be taken when planting. Simply mounting a central bulk fill assembly to a stack-fold planter, such as planter  12 , can create stability issues, especially when the stack-fold planter is in the transport position. In this regard, the present invention provides a mechanism for raising the bulk fill assembly  30  when the stack-fold planter  10  is in the folded, transport position. Raising the bulk assembly  30  provides greater stability during transport as well provides increased clearance between the bulk fill assembly  30  and the roadway. 
     Turning now to  FIG. 5 , the present invention provides a communications apparatus  94  for use with a prime mover equipped with ISO 11783 technology. The communications apparatus  94  includes datalink  96  that communicatively links an implement electronic control unit (ECU)  98  with electronics  100  of the prime mover  14 . The datalink  96  may be a wireless connection or, as shown in  FIG. 5 , a wired communication consisting a connector  102  tethered by cable  104  to the electronics  100  and a receiver  106  tethered by cable  108  to ECU  98 . In a preferred embodiment, the connector  102  and the receiver  106  are ISO 11783 components that permit the transfer of data between the prime mover electronics  100  and the ECU  98 . Thus, it will be appreciated that the datalink  96  provides an ISOBUS connection between the prime mover  14  and the stack-fold implement  12 . 
     The ISOBUS connection enables the transmission of various data between the stack-fold implement  12  and prime mover  14 . One type of data is hitch position information. The prime mover  14  has a hitch position sensor  110  that provides feedback to the electronics  100  of the prime mover  14  as to the vertical position of the coupling between the stack-fold implement  12  and the prime mover  14 . In one embodiment, this coupling is a three-point hitch. The prime mover electronics  100  provides a data signal to the ECU  98  via datalink  96  containing hitch position information. In accordance with one aspect of the invention, the ECU  98  adjusts the vertical position of the stack-fold implement  12  accordingly. 
     More particularly, the stack-fold implement  12  has a frame position sensor  112  that measures the vertical position of the central bulk fill assembly  30 . In one preferred embodiment, the vertical position is determined from the angle between frame  36  and the wheel lift assembly  50 . It is contemplated that a number of sensors may be used to measure this angle including, but not limited to, rotary potentiometers, displacement sensors, optical sensors, strain gauges, pressure sensors, and the like. For example, in one embodiment, the frame position sensor measures the displacement of either hydraulic lift cylinder  76  or hydraulic lift cylinder  78 . 
     The ECU  98  receives the frame position signal from the frame position sensor  112  and compares the frame position of the stack-fold implement  12  with the vertical position of the hitch, as provided in the hitch position signal. From this comparison, the ECU  98  raises or lowers the central bulk fill assembly  30  to level the central bulk fill assembly  30  in light of the changes in vertical position of the prime mover hitch. 
     In one embodiment of the invention, the central bulk fill assembly  30  is raised or lowered by ECU  98  controlling operation of an electric over hydraulic valve  114 . The hydraulic valve  114  is interconnected between the hydraulics  115  of the prime mover  14  and the hydraulics of the stack-fold implement  12 , which include the pair of hydraulic lift cylinders  76 ,  78 . Thus, the hydraulic valve  114 , upon receipt of a corresponding command signal from the ECU  98 , can increase or decrease the pressure in the pair of hydraulic lift cylinders  76 ,  78  to raise or lower, respectively, the central bulk fill assembly  30 . It is highly desirable to increase the elevation of the central bulk fill assembly  30  when the hitch is raised and, conversely, lower the elevation when the hitch is lowered. 
     In a further embodiment of the invention also shown schematically in  FIG. 5 , the wing sections  20 ,  22  are moved automatically based on the vertical position of the three-point hitch. As known in the art, the hydraulic components, including lift actuators  116 ,  118 , are used to raise and lower the left wing section  22  (“left side gull wing”) and the right wing section  20  (“right side gull wing”), respectively. In this further embodiment, the ECU  98  also provides command signals to the left and right lift actuators, which can be of conventional design. In a preferred embodiment, the lift actuators are hydraulic cylinders whose operation is controlled by a valve, such as hydraulic valve  114 . As such, the ECU  98  provides control commands to the hydraulic valve  114  which in turn controls operation of the lift actuators preferably in synchrony with the wheel lift assembly  50 . 
     It will be appreciated that the wing sections are movable between a field working position, such as illustrated in  FIG. 2  and a retracted or raised position, such as illustrated in  FIG. 3 . In the field working position, the wing sections (as well as the center section) are free to float so to respond to changes in surface contours. In this regard, the ECU  98  commands the electric over hydraulic valve  114  to control hydraulic fluid flow in the hydraulic system to move the wing sections to the float position when the hitch is in a fully lowered position. 
     It will also be appreciated that in the embodiment illustrated in  FIG. 5 . the operator of the tractor, i.e., towing vehicle, using conventional hydraulic remotes, pressurizes the tractor&#39;s hydraulic system to which the hydraulics of the implement are flow-coupled and thus also pressurized. As such, the operator must manually operate the hydraulic remotes to supply the hydraulic power needed to operate the lift actuators for the gull wings and the central bulk fill assembly. 
     In contrast, and referring now to  FIG. 6 , a communications apparatus  120  according to an alternate embodiment of the invention controls operation of the hydraulic remotes automatically, i.e., uses the tractor hydraulics  122  to directly control operation of the wheel lift assembly  50  and the lift actuators  116 ,  118  rather than control an electronic-over-hydraulic valve  114 . More particularly, the hitch position sensor  110  provides hitch position data to the implement ECU  98  across ISOBUS connection  96 . The implement ECU  98  uses the hitch position information together with frame position data read from the frame position sensor  112  and provides control commands to the hydraulic remote(s)  124 , which are connected to the tractor hydraulics  122  in a known manner. The tractor hydraulics are flow-coupled to the actuators of the wheel lift assembly  50  and the lift actuators  116 ,  118 . It is understood that the actuators could be independently flow coupled to the tractor hydraulics, but preferably, a single supply conduit  126  and return conduit  128  that are coupled to a manifold  130  or similar distribution device to which the actuators for the wheel assembly and the lift actuators are flow coupled in a conventional manner. It will thus be appreciated that in the embodiment illustrated in  FIG. 6 , the implement controls the hydraulics of the tractor based on commands transmitted to the tractor via the ISOBUS connection. 
     It will be appreciated that in one embodiment of the invention, the position of the tractor hitch is used to adjust the vertical position of the implement frame. It is understood however that in another embodiment, the vertical position of the implement frame could be monitored to cause automatic adjustment of the tractor hitch. 
     Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.