Abstract:
A planter row unit is disclosed having an active downforce control system for the closing wheels. This separate control of the downforce pressure for the closing wheels is provided from the row unit downforce control. A single operator input is used to set a desired downforce for all row units. The control system then operates to produce the desired downforce. Alternatively, the control system may display a downforce load to the operator who then manually makes adjustments as desired.

Description:
FIELD 
       [0001]    This disclosure relates to seeding machines and in particular to an active downforce control system for the closing wheels of a seeding machine row unit. 
       BACKGROUND AND SUMMARY 
       [0002]    It is known in the seeding art to provide active control of downforce on a row unit of a seeding machine such as a planter to ensure the furrow opener is operating at a proper depth and to control the downforce to provide only as much downforce as is needed. This reduces unnecessary soil compaction adjacent the seed furrow. However, the proper downforce for the opener does not always provide the proper downforce on the closing wheels. An adjustable spring is typically provided between the closing wheels and the row unit frame. This can be set by the operator before, operation and if needed, the operator can stop planting and readjust the closing wheels downforce springs. However, operators seldom will take the time to adjust the closing wheel downforce springs during planting. 
         [0003]    A row unit is disclosed having an downforce control system for the closing wheels. The closing wheel downforce control may be active, that is closed loop, or inactive, that is open loop. This control of the downforce pressure for the closing wheels can be separate from the row unit downforce control or can be related to the row unit downforce control by making the closing wheel downforce proportional to the row unit downforce. In a closed loop control, operator input to the control system is used to set a desired downforce for the closing wheels. The control system then operates the downforce actuator to produce the desired downforce. In an open loop control, a monitor displays a load to the operator who then commands operation of the downforce actuator to change the downforce on the closing wheels as desired. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a perspective view of a row unit of a seeding machine; 
           [0005]      FIG. 2  is a side view of the closing wheel arrangement of the row unit of  FIG. 1  with one closing wheel removed to illustrate the arrangement; 
           [0006]      FIG. 3  is a bottom perspective view partial sectional view of the closing wheel arrangement; 
           [0007]      FIG. 4  is a sectional view along the line  4 - 4  of  FIG. 2 ; 
           [0008]      FIGS. 5 and 6  are schematic diagrams of the downforce control system for the seeding machine. 
       
    
    
     DESCRIPTION 
       [0009]    Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a portion of a seeding machine  10 . As shown, seeding machine  10  is in the form of a row crop planter but may also be other forms of machines.  FIG. 1  illustrates a single row unit  12  of a multi-row planter, with each row crop unit  12  being substantially identical and connected to a machine frame  14  shown as a tool bar. Only a single row crop unit  12  is shown and described below for sake of simplicity. Row crop unit  12  includes a multi-part row unit frame  16  which is attached to tool bar by parallel linkage  18 . The tool bar is coupled to a traction unit (not shown), such as an agricultural tractor. For example, tool bar may be coupled to an agricultural tractor using a draw bar or 3-point hitch assembly. The tool bar may be coupled with transport wheel assemblies, marker arms, etc. which may be of conventional design and not shown for clarity. 
         [0010]    Frame  16  carries a double disc furrow opener  20  for forming a seed furrow  26  in soil  27 . An optional coulter wheel  22  and row cleaner  23 , particularly for use in no till situations, may be placed ahead of double disc furrow opener  20 . A pair of furrow depth regulating members  25  in the form of gauge wheels  24  are respectively associated with the pair of discs of double disc furrow opener  20 . More particularly, each gauge wheel  24  is positioned generally in line with and immediately adjacent to the outside of each respective disc of double disc furrow opener  20 . The gauge wheels  24  may be vertically adjusted to change the depth of the furrow which is cut into the soil using double disc furrow opener  20 . 
         [0011]    A seed meter  32  is also carried by frame  16 . Seed meter receives seed from a seed hopper  28  carried above the seed meter on the frame  16 . The seed meter drive is not shown. Seed meter  32  delivers seed sequentially to a seed tube  36  through which the seed falls by gravity to the furrow  26 , or other delivery device. A furrow closing arrangement follows behind the gauge wheels with a pair of closing wheels  42  positioned generally in line with double disc furrow opener  20 . Closing wheels  42  are preferably biased in a downward direction and have a peripheral edge with a shape which may vary, depending upon the application. Closing wheels  42  push soil back into the furrow  26  upon the seeds deposited therein. Closing wheels  42  serve as a ground contacting member. 
         [0012]    The row unit  12  is equipped with a row unit downforce actuator  43  in the form of an adjustable pneumatic downforce cylinder  44 . The row unit downforce actuator  43  acts between the machine frame  14  and the lower links of the linkage  18  to apply downforce on the row unit to ensure there is a desired force of the gauge wheels  24  acting on the soil. This ensures that the double disc furrow opener  20  is forming the furrow  26  to the desired depth. The amount of the downforce on the row unit, and thus the force of the soil on the gauge wheels  24 , is measured by a load sensor in the pivot pin  46  in the gauge wheel depth adjustment link  48 . A suitable load sensing pin is shown in WO2008/086283 A2. Load sensors can be placed in a variety of locations on the gauge wheel support arm  49  or adjustment link  48 . As described more fully below, a controller receives a signal from the load sensor in the pin  46  and controls the pressure in the cylinder  44  accordingly to achieve a desired downforce on the gauge wheels. 
         [0013]    To ensure proper closing of the seed furrow  26 , the furrow closing arrangement  40  provides for controlled downforce on the closing wheels. The control can be dynamic, that is changing the downforce during operation of the machine, either automatically (closed loop) or manually (open loop). Furrow closing arrangement  40  includes a mounting frame  50  ( FIGS. 2-4 ) attached to the row unit frame  16  at the rear thereof. Shelf  51  of the mounting frame  50  is used to attach the mounting frame to the row unit frame  16 . While the mounting frame  50  is a separate piece, once attached to the frame  16 , it functions as part of the row unit frame  16 . The mounting frame  50  is a separate piece to enable other closing options to be installed in the row unit but could be integrated into the frame  16  if desired. A pivot arm  52  is rotatably coupled to the row unit frame, via the mounting frame  50 . The closing wheels  42  are mounted to the pivot arm  52 . The pivot arm  52  serves as a first link in a parallelogram linkage  54 . Linkage  54  includes a second link  56  and a coupler  58  connected to the first link, i.e. pivot arm  52 , and to the second link  56 . A pneumatic cylinder  60  is connected between the mounting frame  50  and the coupler  58  and serves as a furrow closing downforce actuator  61 . When pressure in the cylinder  60  is increased, the closing wheels  42  exert a greater force on the soil to close the furrow  26 . 
         [0014]    As shown in  FIG. 3  a slide member  62  connects the coupler  58  to the pivot arm  52 . This allows for a limited degree of lateral movement of the pivot arm  52  while the cylinder  60  and coupler  58  remain fixed laterally. The coupler  58  only moves in a vertical direction.  FIG. 4  is a sectional view through the attachment of the pivot arm  52  to the mounting frame  50 . The attachment of each leg  66  is symmetrical. Bolt  67  and nut  68  attach the leg to the mounting frame using a bushing  69 . The leg  66  does not directly contact the mounting frame  50 . Instead, the bushing  69  engages the mounting frame  50 . The bushing surface  70  is curved and complementary to the curved surface  71  of the mounting frame. The bolt  67  extends through a fore and aft extending slot  72  in the mounting frame. The slot and the curved surfaces  70  and  71  allow the pivot arm  52  to be adjusted about a vertical axis to adjust the side-to-side location of the closing wheels  42  to ensure they are center over the furrow  26 . The bushing  69  has a projection  73  that is seated into the slot  72  to orient the bushing properly for mating of the surfaces  70  and  71 . The slide member  62  allows the pivot arm to be adjusted without affecting the location of the lower end of the cylinder  60 . 
         [0015]    The bolt  64  that connects the slide member  62  to the pivot arm  52  can be a load sensing pin having a load sensor similar to the pin  46  mentioned above. The sensor measures the load acting on the soil from the closing wheels. The bolt  64  is only one position of many that may be suitable for a load sensor to measure the load on the closing wheels. Any of the pivot pins in the closing wheel arrangement may be used to measure the load. Alternatively, a load cell may be attached to or integrated into the pivot arm or other links in the closing wheel arrangement. 
         [0016]    A control system  74  is shown schematically in  FIG. 5 . A controller  76  receives a load signal from a load sensor  78  such as the bolt  64 . An input device  80  enables a machine operator to input a desired downforce into the controller. The controller in turn generates a signal for an air pressure source  82 , causing the pressure to increase or decrease. The air pressure is then directed to the actuator, or pneumatic cylinder  60 . It will be readily appreciated that the pressure source  82  could be a fixed, that is constant, pressure source and the controller connected to a regulating valve between the pressure source and the cylinder  60 . As used herein, reference to the controller being operably connected to an actuator to vary the load applied to the soil is meant to mean the controller is connected to a pressure source or pressure control valve for pressure operated actuators or to an electrical control for an electric actuator. Any connection that enables the controller to operate the actuator is intended to be included. 
         [0017]    An open loop control system  90  is shown in  FIG. 6 , where like components from control system  74  are given the same reference numeral. In control system  90 , the controller is replace with a monitor  92 . The monitor  92  receives the output signal from the load sensor  78  and displays the load to an operator. The operator then uses the input device  80  to control the pressure to operate the furrow closing downforce actuator  60 . As shown, the input device operates through the monitor  92 . Alternatively, the operator input can be directly to the pressure source  82  or a pressure regulating valve, etc. 
         [0018]    The control system is capable of dynamic (closed loop control) or open loop control to vary the downforce on the closing wheels with varying field conditions as the seeding machine moves through a field. Alternatively, the control system can be used to initially set the air pressure in the cylinder and then not change the pressure during operation. In such a case, the load sensor  78  is not needed. Such a system would provide an advantage over a mechanical closing downforce system in that a single input to the controller or manual valve adjustment can adjust the closing wheel downforce on all or multiple row units without the need to manually adjust springs on each row unit individually. One load sensor  78 , on one row unit  12 , can be used as the feedback input to control the pressure in the cylinders  60  of multiple row units on the seeding machine. In other words, a load sensor is not needed for every row unit  12 . Perhaps one load sensor for each section of the seeding machine frame is sufficient. 
         [0019]    Another control system  86  is shown in  FIG. 7  with components common between the control system  74  and control system  86  given the same reference numeral and not described again. Control system  86  uses one load sensor for measuring the downforce on the row unit. The load measured by the one sensor  78  is used in the control of both the row unit downforce and the closing wheel downforce. Alternatively, two or more load sensors can may be used in control system  86 , one measuring the load on the furrow depth regulating member and another measuring the load on the closing wheel. Control system  86  has valve  88  connected to the pressure source  82  and supplies pressure to both the cylinder  60  for the closing wheel downforce actuator and the cylinder  44  for the row unit downforce. Valve  82  controls the pressure independently to the two actuators  44 ,  60 , that is each actuator can be supplied with a different pressure. Thus a single control system is used to control both the row unit downforce and the closing wheel downforce. Valve  88  could be two separate valves if desired. Having two separate actuators for the row unit downforce and the furrow closing wheel downforce with independent control of the pressure to the two actuators, allows maximum flexibility to the operator in the control of row unit and closing downforce. Alternatively, a pressure regulator could be used to link and/or adjust forces between the two systems in an open-loop or closed-loop manner. Multiple cylinders  60  and  44  from multiple row units can be controlled with one controller  76  or manual adjustment. 
         [0020]    In its simplest form, the closing wheel downforce arrangement includes an actuator operable to vary the downforce on the closing wheels as the machine moves through a field and an operator accessible switch or control to activate the actuator to vary the downforce. A load sensor and a monitor for the operator to see the measured load are optional. 
         [0021]    While the closing wheel downforce arrangement is disclosed and described in the context of a pneumatic cylinder used as the actuator, other actuators can be used such as a hydraulic, electronic or electro-mechanical, etc. The type of actuator is not critical. By providing control of the closing wheel downforce, the machine operator is better able to assure the seed furrow is properly closed. A pressure based actuator, pneumatic or hydraulic allows for more constant downforce across a range of loads compared to a mechanical system. 
         [0022]    While a pair of closing wheels  42  have been shown, it will be appreciated that any of a variety of ground contacting members can be used in place of the closing wheels  42 . Alternatives include a packing wheel, a single closing wheel, a tine type closing device or any combination thereof, etc. Additional attachments can be mounted at the rear end  53  of the pivot arm  52 . 
         [0023]    Having described the seeding machine, it will become apparent that various modifications can be made within the scope of the accompanying claims.