Abstract:
An agricultural device includes a number of row units that each includes a seed furrow opener that creates a furrow in the soil for seed placement. Each row unit is mounted to a toolbar of the device by a four-bar linkage which allows each row unit to move vertically to adjust to the contour of the soil independently of the other row units on the same toolbar. The four-bar linkages include one or more springs which work to transfer weight from the toolbar to the row unit. An actuator varies the tension in the spring thereby adjusting the down or up force applied to the row unit.

Description:
RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application Nos. 61/479,540, filed Apr. 27, 2011, 61/479,537, filed Apr. 27, 2011, and 61/479,543, filed Apr. 27, 2011, the contents of all are hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to agricultural devices and, more particularly, to down force adjustment of a row unit of an agricultural device. 
     BACKGROUND 
     Implements for planting row crops, such as corn and soybeans, (planters) typically include row units laterally spaced along a frame, or toolbar. The row units generally include a seed channel opener that creates a channel or furrow in the soil for seed placement. Each row unit is mounted to the toolbar by means of a four-bar linkage or its equivalent which allows each row unit to move vertically to adjust to the contour of the soil independently of the other row units on the same toolbar. Some planters have springs in the four-bar linkage which work to transfer weight from the planter&#39;s frame to the row unit creating down force to help the seed channel opener penetrate the soil and to minimize row unit bounce in rough soil conditions. Insufficient down force can result in a seed furrow of inadequate depth or a seed furrow simply not formed, which in turn results in shallow seed placement or seed placement on the soil surface. However, too much down force could overly compact the seed bed or form the seed furrow too deep, which could negatively affect early plant development. Furthermore, excessive down force could accelerate wear on the row units&#39; soil-engaging components. The springs can be adjusted to adjust the down force of the row unit. This adjustment usually is made by manually changing the position of the springs in the four-bar linkage. 
     In other planters, airbags are employed in the four-bar linkage which are similarly adapted to transfer weight from the planter&#39;s frame to the row unit creating down force to help the seed channel opener penetrate the soil and to minimize row unit bounce. In both of these conventional biasing means—springs and airbags—the system lacks accuracy and predictability. For instance, when the biasing means is an airbag, it can be difficult to precisely determine the volume of air in the airbag at a given time and, subsequently, determine needed supplemental down force. 
     It is desirable to be able to adjust down force on a row unit quickly and accurately so that a consistent seed depth is maintained. It is also desirable to be able to lift the row unit if its own weight is applying too much down force to the soil. 
     SUMMARY 
     Accordingly, it is an object of the present invention to provide for a quick and accurate adjustment of the down force on a row unit during planting. 
     It is another object of the present invention to provide the capability to put both positive and negative pressure on the row unit. 
     These and other objects are achieved by the present invention. In some exemplary aspects of the present invention, a row unit of a planter is provided. The row unit is mounted to a toolbar of a planter by means of a four-bar linkage having a set of top and bottom parallel arms. At least one spring is provided between the top and bottom arms and connected at one end to the bottom arm in a fixed manner at a connection point. The other end of the spring is connected to a spring mount that is disposed on the top arm and coupled to an electric actuator. The spring mount is longitudinally movable in both directions of the top arm. The electric actuator moves the spring mount forward and backward along the top arm, which adjusts the down or up force placed on the row unit, which in turn can increase or decrease the soil penetration of a seed channel opener component of the row unit, and keep the row unit from bouncing in rough soil conditions. 
     In other exemplary aspects, an agricultural device is provided and includes a toolbar, a row unit, a linkage coupling the row unit to the toolbar, wherein the linkage includes a first arm and a second arm, and wherein each of the first arm and the second arm includes a first end coupled to the toolbar and a second end coupled to the row unit, an actuator coupled to the toolbar, and a biasing member coupled to the linkage and the actuator, wherein the actuator is adapted to move the biasing member to vary an amount of force applied to the row unit. 
     In further exemplary aspects, a row unit adjustment system for use in an agricultural planter for planting seeds is provided. The agricultural planter includes a toolbar and a row unit coupled to the toolbar by a linkage. The row unit adjustment system includes an actuator including an adjustment member, a biasing member coupled to the linkage and the adjustment member, a sensor adapted to sense a characteristic associated with planting seeds and generate a signal associated with the sensed characteristic, and a processing unit receiving the signal associated with the sensed characteristic and determining whether adjustment of the biasing member is necessary based on the signal. 
     In still other exemplary aspects, a method for adjusting a force applied to a row unit of an agricultural planter is provided. The agricultural planter includes a toolbar and the row unit includes a linkage coupling the row unit to the agricultural planter. The method includes providing an actuator including an adjustment member, coupling a biasing member at a first end to the linkage and at a second end to the adjustment member, sensing a characteristic associated with planting with a sensor, generating a signal associated with the characteristic with the sensor, communicating the signal to a processing unit, and adjusting a position of the biasing member with the actuator based on the signal received by the processing unit in order to adjust a force applied to the row unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The appended claims set forth those novel features which characterize the invention. However, the invention itself, as well as further objects and advantages thereof, will best be understood by reference to the following detailed description of an exemplary embodiment, taken in conjunction with the accompanying drawings, where like reference characters identify the elements throughout the various figures in which: 
         FIG. 1  is a side elevation view of a portion of an exemplary planter row unit, the exemplary row unit including an exemplary down force adjustment system; 
         FIG. 2  is a side elevation view similar to  FIG. 1  showing a down force spring of an exemplary down force adjustment system adjusted to provide a negative down force on the row unit; 
         FIG. 3  is a side elevation view similar to  FIGS. 1 and 2  showing a down force spring of an exemplary down force adjustment system adjusted to provide a positive down force on the row unit; 
         FIG. 4  is an exemplary system diagram of the present invention; and 
         FIG. 5  is a side elevation view of a portion of an exemplary planter row unit including an exemplary soil characteristic sensor. 
     
    
    
     Before any independent features and embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
     The contents of U.S. patent application Ser. No. 13/458,012, filed Apr. 27, 2012, entitled “AGRICULTURAL DEVICES, SYSTEMS, AND METHODS FOR DETERMINING SOIL AND SEED CHARACTERISTICS AND ANALYZING THE SAME”, and U.S. patent application Ser. No. 13/457,577, filed Apr. 27, 2012, entitled “REMOTE ADJUSTMENT OF A ROW UNIT OF AN AGRICULTURAL DEVICE”, are both incorporated herein by reference. 
     Referring to  FIG. 1 , there is shown a side elevation view of an exemplary planter row unit  10  in accordance with the principles of the present invention. A single row unit  10  is depicted in the figures and described herein for simplicity, but it is understood that a typical planter  36  (see  FIG. 4 ) includes multiple row units  10 . Row unit  10  includes a frame  12 . Mounted to the lower section of frame  12  are a pair of furrow-opening discs  14  (one of which is seen in  FIGS. 1-3 ), a pair of depth gauge wheels  16  (one of which is seen in  FIGS. 1-3 ) and a pair of furrow closing wheels (not shown). As is known, seed is stored in a hopper (not shown), fed to and “singulated” by a meter (not shown) and deposited at desired spacing in the furrow formed by the furrow-opening discs  14 . The furrow is then closed and soil is packed about the seed by the closing wheels. 
     The row unit  10  is mounted to a toolbar (not shown) by a conventional four-bar linkage  18 . Four-bar linkage  18  includes parallel top arms  20  (one of which is seen in  FIGS. 1-3 ) and parallel bottom arms  22  (one of which is seen in  FIGS. 1-3 ) on each side of the row unit  10 . The forward ends of the top arms  20  are pivotally connected to an upper portion of a mounting plate  24 . Likewise, the forward ends of the bottom arms  22  are pivotally connected to a lower portion of the mounting plate  24 . Mounting plate  24  is in turn coupled to the toolbar. A conventional mounting arrangement for attaching the mounting plate  24  to the toolbar would typically include threaded U-shaped bolts and mounting nuts which are not shown in the drawing for simplicity. The rear ends of top and bottom arms  20  and  22  are pivotally connected to row unit frame  12 . 
     The top and bottom arms  20  and  22  are connected to both the mounting plate  24  and row unit frame  12  by means of a nut and bolt combination which allows the top and bottom arms  20  and  22  to pivot at both ends. The four-bar linkage  18  permits the row unit  10  to move vertically, independently of adjacent row units, while remaining laterally in place on the toolbar. 
     At least one linear actuator  26  is mounted to the mounting plate  24  above a top arm  20  of the linkage  18 . In other exemplary embodiments, a linear actuator  26  may be provided above each top arm  20  of the linkage  18 . Linear actuator  26  can be of an electric, hydraulic or air type, having a shaft  28  that extends longitudinally parallel to the top arm  20 . A mounting bracket  30  is provided on top arm  20  and coupled to the shaft  28 . The mounting bracket  30  engages and is supported by a top surface of top arm  20  and may slide, roll, or otherwise move along the top surface of the top arm  20 . During up and down movement of the row unit  10 , shaft  28  pivots about pin or pivot  29  to maintain the shaft  28  substantially parallel to the top arm  20 . At least one biasing member  32  under tension is provided between top and bottom arms  20 ,  22 . In the illustrated exemplary embodiment, the biasing member  32  is a spring or coil spring. However, it should be understood that the biasing member  32  may be any type of biasing member and other types of springs and still be within the intended spirit and scope of the present invention. In exemplary embodiments including an actuator  26  above each top arm  20 , two tension springs  32  may be included in the linkage  18  with one spring  32  coupled to each actuator  26 . In other exemplary embodiments, one actuator  26  and two springs  32  may be included in the linkage  18  with one spring  32  coupled to the actuator  26  and the second spring  32  coupled to and between the top and bottom arms  20 ,  22 . In the illustrated exemplary embodiment, the spring  32  is connected at a lower end to the bottom arm  22  at a fixed point and at an upper end to the mounting bracket  30  on the top arm  20 . The tension applied across the tension spring  20  may be varied to adjust the tension on spring  32  and thus the amount of weight transferred from the toolbar to the row unit  10  by extending or retracting the shaft  28  of the actuator  26 , which in turn will move the mounting bracket  30  forward or rearward along the top arm  20 . Alternatively, the actuator  26  may be a screw-drive type actuator  26 , and the shaft  28  and the mounting bracket  30  may have a screw or threaded engagement between the two components, thereby causing the mounting bracket to translate along the shaft  28  as the shaft  28  rotates. The shaft  28  may rotate either direction to enable the mounting bracket  30  to translate in either direction. 
     With continued reference to  FIG. 1 , dt denotes the distance between the proximal pivot point of the top arm  20  and the mounting bracket  30 , which is the connection point of the upper end of the spring  32 , and db denotes the distance between the proximal pivot point of the bottom arm  22  and the fixed connection point of the lower end of the spring  32 . As shown in  FIG. 1 , when dt and db are the same, the spring  32  is in a neutral position where the net effect on the force applied to the soil F g  is zero. As shown in  FIG. 2 , when the actuator  26  retracts the shaft  28 , the mounting bracket  30  is moved to a position closer to the proximal pivot point of top arm  20 . In this position the spring  32  is in a negative, or up force position in which dt is less than db, and where a net negative force will be put on the row unit  10  which decreases the force applied to the soil by the furrow-opening discs  14 . 
     As shown in  FIG. 3 , when the actuator  26  extends the shaft  28 , the mounting bracket  30  is moved to a position further from the proximal pivot point of top arm  20 . In this position, the spring  32  is in a positive, or down force position in which dt is greater than db, and where a net positive force will be applied to the row unit  10 . This increases the force that is applied to the soil by the furrow-opening discs  14 . 
     With continued reference to  FIGS. 1-3 , an exemplary sensor  34  is provided to sense or determine a position of the biasing member  32 . In the illustrated exemplary embodiment, the sensor  34  is coupled to the mounting plate  24 . In other exemplary embodiments, the sensor  34  may be coupled to any portion of the toolbar, linkage  18 , row unit  10 , etc. and still be within the intended spirit and scope of the present invention. The sensor  34  may be any type of sensor for determining a position of the biasing member  32 . For example, the sensor  34  may be an ultrasonic sensor, a laser sensor, a potentiometer, a hall effect sensor, or any other type of sensor. In other exemplary embodiments, the sensor  34  may be coupled to or included within the actuator  26  and may be a wide variety of types of sensors such as, for example, a potentiometer, a hall effect sensor, etc. 
     The actuator  26  is controlled by conventional means via a user interface  40 , which can be in the cab of a tractor  38  that pulls the planter  36  and row units  10  through a field. In this way, a farmer can adjust down force on the row unit  10  quickly and accurately so that furrow-opening discs  14  can maintain a consistent furrow depth, or the farmer can lift the row unit  10  if its own weight is applying too much down force to the soil. 
     Referring now to  FIG. 4 , an exemplary system of the present invention is illustrated and includes a tractor  38  and a planter  36 . The tractor  38  includes a control system  39  including a user interface  40  with an optional touch screen  42  and associated touch screen capabilities, a processing unit  44 , an optional mechanical control panel  46 , and a memory  48 . The tractor  38  also includes a tractor electrical power source  50 . The planter  36  includes multiple row units  10 , however, since the row units  10  are substantially identical, only one row unit  10  is illustrated with further detail and described herein. Each row unit  10  includes a down force adjustment assembly including the actuator  26 , the biasing member position sensor  34 , a down force sensor  52 , and a soil characteristic sensor  54  (see  FIGS. 4 and 5 ). Each row unit  10  may include an optional row unit electrical power source  56  and the planter  36  further includes a planter electrical power source  58 . In other exemplary embodiments, the planter  36  may include a processing unit and/or the row units  10  may each include a processing unit and the processing unit(s) of the planter  36  and/or the row units  10  may communicate with the processing unit  44  of the tractor  38  via a communication bus. 
     The down force sensor  52  may be, for example, a force transducer that is coupled to a depth-adjusting lever mechanism  60  (see  FIG. 5 ) or the gauge wheels  16  for monitoring and/or measuring a down force occurring in the depth-adjusting mechanism  60  or the gauge wheels  16  and applied to the row unit  10  to force the row unit  10  downward toward the soil. The down force sensor  52  may be any type of sensor such as, for example, a load cell, a pressure sensor, a potentiometer, etc., and may be coupled to any portion of the row unit  10  as long as it can operate appropriately to sense a down force. Such a force sensor  52  may be electronically coupled to the processing unit  44  to enable the processing unit  44  to take readings of the down force and display related information to a user via the user interface  40  or to enable the processing unit  44  to communicate with the necessary components to adjust the down force. 
     With further reference to  FIG. 5 , an exemplary soil characteristic sensor  54  is illustrated and may be coupled to the row unit  10  in any manner and at any location as long as the sensor  54  can sense desired soil characteristic(s). The soil characteristic sensor  54  may sense any soil characteristic and operate in any of the manners described in U.S. Provisional Patent Application Nos. 61/479,537 and 61/479,543, both of which were filed Apr. 27, 2011 and both of which are incorporated herein by reference. 
     All of the sensors may generate a signal associated with the characteristic they are sensing and communicate with the processing unit so the processing unit may receive the signals, interpret the signals, and react accordingly to perform the desired functions of the system. 
     It should be understood that the sensors described and illustrated herein may be any type of sensor and be within the intended spirit and scope of the present invention. Exemplary sensors include, but are not limited to, ultrasonic sensors, laser sensors, video cameras, infra-red sensors, infra-red cameras, infra-red scanners, microwave sensors, potentiometers, hall effect sensors, force transducers, etc. 
     The foregoing description has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The descriptions were selected to explain the principles of the invention and their practical application to enable others skilled in the art to utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. Although particular constructions of the present invention have been shown and described, other alternative constructions will be apparent to those skilled in the art and are within the intended scope of the present invention. 
     While particular embodiments of the present invention have been illustrated and described, it will be obvious to those skilled in the relevant arts that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications that fall within the true spirit and scope of the invention. The matters set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.