Abstract:
An agricultural planter including a frame member, a conveyance system, a seeding system and an air pressure differential system. The conveyance system is coupled to the frame member and the conveyance system allows for the moving of the planter at a ground speed. The seeding system is coupled to the frame member. The air pressure differential system is operatively coupled to the seeding system. The air pressure differential system includes an air pressure differential producing apparatus for producing an air pressure difference and a controller. The controller is in controlling communication with the air pressure differential producing apparatus. The controller is configured to select the air pressure difference dependent upon the ground speed of the planter.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to air pressure controls used in the agricultural field, and, more particularly, to an air pressure control system used on planters. 
         [0003]    2. Description of the Related Art 
         [0004]    Agricultural planters are commonly used implements to plant seeds in soil. An agricultural planter can include a chassis that carries one or more storage tanks carrying seed, and chemical applications that are to be applied to the field during the planting operation, a hitch mechanism that attaches to a tractor or other implement pulled by a tractor, and a tool bar that row units can be connected to so they are carried by the chassis. The planter can also include a pneumatic system carried by the chassis that supplies pressurized air to transport the seeds or other particulate from the storage tanks to the row units. 
         [0005]    Each row unit of the agricultural planter independently places seeds in the field. Typically, the row units are laterally arranged along a length of the tool bar so that as the planter is pulled across the field, each row unit plants seeds at predefined intervals along the path it is pulled across. To plant seeds, the row units perform four main operations as they are pulled: opening a trench in the soil; placing a seed into the formed trench at appropriate intervals; closing the formed trench to put soil on top of the placed seed; and packing soil on top of the seed to provide desirable soil contact with the placed seed. To open a trench in the soil, a furrowing disc system, also called an opening disc, cuts into the soil and rotates, dislocating soil as it rotates to form the trench. Once the trench is open, a seed is placed in the trench by a metering device which receives seeds from the main storage tank(s) or a row unit storage tank and typically utilizes a combination of differential air pressure, to select the seed, and gravity to place the seed in the trench at predefined intervals along the pulled path so that adjacent seeds in the row are not too close to one another. One or more closing discs carried behind the furrowing disc are pressed into the soil and also rotate as the planter is pulled to replace soil dislocated by the furrowing disc in the trench or dislocate adjacent soil into the trench to cover the seed placed in the trench with soil. Finally, a pressing wheel carried behind the closing disc(s) exerts pressure on the soil covering the seed to press the soil down onto the seed and provide good soil contact with the seed. By having multiple row units working in unison as the planter is pulled across a field, many seeds can be effectively planted in an efficient manner. 
         [0006]    The vacuum fan has a key roll in the apparatus used for planting seeds in a field. Among other possible functions, it is used to create a pressure differential within a series of seed metering devices, which results in seeds adhering onto a metering disk so that they may be accurately and consistently delivered through the planter mechanism to the soil. The fan for this purpose typically has a high flow rate owing to the number of planter components. In the arrangement of the planter, the fan is coupled to the planter that is behind the operator of a tractor used to pull or support the planting apparatus. The inlet or suction side of the fan is connected to the seed metering mechanisms. The rotational speed of the fan is set by a selection of the operator and is generally in the 3,000 to 5,000 RPM range, depending upon the capacity of the fan and the number of row units connected. The speed of the fan or vacuum level, having been selected, is maintained during the planting operation until the set point is reselected by the operator. 
         [0007]    A problem with the prior art is that the fan speed or the vacuum level selected by the operator is not altered even though the planter changes operating speeds and executes turns. Another problem is that the force required to transition a seed from a stationary position to a dynamic position increases as the velocity of the metering device increases, proportional to the travel speed, and conversely as the travel speed decreases and this is not compensated for in the prior art. 
         [0008]    Accordingly, what is needed in the art is a vacuum fan that is responsive to changes in the operating conditions of the planter. 
       SUMMARY OF THE INVENTION 
       [0009]    The invention seeks to provide an air pressure differential control sensitive to changes in planting speeds and seed delivery parameters. 
         [0010]    In one form, the invention is directed to an agricultural planter including a frame member, a conveyance system, a seeding system and an air pressure differential system. The conveyance system is coupled to the frame member and the conveyance system allows for the moving of the planter at a ground speed. The seeding system is coupled to the frame member. The air pressure differential system is operatively coupled to the seeding system. The air pressure differential system includes an air pressure differential producing apparatus for producing an air pressure difference and a controller. The controller is in controlling communication with the air pressure differential producing apparatus. The controller is configured to select the air pressure difference dependent upon the ground speed of the planter. 
         [0011]    In another form, the invention is directed to an air pressure differential system for use on an agricultural planter, the planter capable of being towed at a ground speed. The air pressure differential system including an air pressure differential producing apparatus for producing an air pressure difference and a controller. The controller is in controlling communication with the air pressure differential producing apparatus. The controller being configured to select the air pressure difference dependent upon the ground speed of the planter. 
         [0012]    In another form, the invention is directed to a method of operating an air pressure differential system of an agricultural planter. The method includes the steps of: detecting, sensing, selecting and adjusting. The detecting step detects a ground speed of the planter. The sensing step senses an air pressure difference generated by the air pressure differential system. The selecting step selects a target air pressure differential value dependent upon the ground speed. The adjusting step adjusts a fan speed in an air pressure differential producing apparatus to thereby cause the air pressure difference to approximate the target air pressure differential value. 
         [0013]    The present invention has certain advantages in that seed metering becomes more efficient, resulting in improved plant stands. 
         [0014]    Another advantage of the present invention includes increasing the robustness of the planting system, allowing it to extend its effective ground speed operations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    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: 
           [0016]      FIG. 1  is a perspective view of an agricultural planter using an air pressure differential system having an embodiment of a control system of the present invention; 
           [0017]      FIG. 2  is a schematic view of the control system used with the planter of  FIG. 1 ; 
           [0018]      FIG. 3  is a flowchart illustrating an embodiment of a vacuum control method carried out on the controller depicted in  FIG. 2 ; 
           [0019]      FIG. 4  is a graph showing an embodiment of an operating curve used by the method of  FIG. 3 ; and 
           [0020]      FIG. 5  is a graph showing another embodiment of an operating curve used by the method of  FIG. 3 . 
       
    
    
       [0021]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one 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 
       [0022]    Referring now to the drawings, and more particularly to  FIG. 1 , there is shown an embodiment of an agricultural planter  10  according to the present invention which generally includes a chassis forming a support structure for components of the planter  10  that can be formed by a hitch assembly  12  at a front of the planter  10  connected to a tool bar  14 , main wheels  16  carried by the chassis near a rear of the planter  10 , one or more storage tanks  18 ,  20 , and  22  that can be filled with seed or other agriculture material carried by the chassis, and a plurality of row units  24  connected to the tool bar  14  and arranged laterally across a length of the tool bar  14  so that they are carried by the chassis. The hitch assembly  12  can include a hitch  26  configured to be connected to a tractor or other agricultural implement (not shown) so that the planter  10  can be pulled in a forward direction of travel. The hitch  26  can be integrally formed with or connected to a hitch bar  28  that is connected to the tool bar  14  by bracing bars  30  and one or more cylinders  32 . As can be seen, the planter  10  can also have various hydraulic, pneumatic, and electrical lines (unnumbered) throughout to support various cylinders and systems that are included on the planter  10 , such as a pneumatic system  34  connected to the tool bar  16  and an electric generator  36  also connected to the tool bar  16 . A marking device  38  can be connected to each lateral end of the tool bar  14  and extendable so that a marking disc  40  of the marking device  38  can create a line in the soil as the planter  10  is pulled that helps a user in positioning the planter  10  to create subsequent rows. A stair assembly  42  can be mounted to the back of the planter  10  to allow for an operator to access the storage tanks  20 ,  22 . 
         [0023]    Now, additionally referring to  FIG. 2  there is shown a schematic representation of an air pressure differential system  70  (for the sake of clarity referred to herein as a vacuum system  70 , although a positive pressure system is also applicable), having a controller  72 , that interacts with a frame position sensor  72 , a ground speed sensor  74  (which can be a GPS, a radar, or a signal sourced from a towing vehicle), a system vacuum sensor  76  and a hydraulic control valve  78 . Hydraulic control valve  78  alters the fluid flow to a hydraulic motor  80  that drives a vacuum fan  82 , which together can be considered a vacuum producing apparatus  84 . Information from sensors  72 ,  74  and  76  respectively let controller  72  know the position of the frame, the ground speed of planter  10  and the level of vacuum that vacuum producing apparatus  84  is producing for the seeder mechanisms of planter  10 . 
         [0024]    Controller  72  is also coupled to a user interface  86 , which may be located on planter  10  or upon a towing vehicle. User interface  86  allows an operator to input information to controller  72 , such as information about the type of seed being planted and the selection of vacuum profiles for the controlling of the level of vacuum being supplied to the seeder units by vacuum producing apparatus  84 . 
         [0025]    Now, additionally referring to  FIG. 3 , there is shown a method  100  for the controlling of the vacuum level measured by vacuum sensor  76 , by controlling the speed of fan  82 . At step  102 , an operator make selections on user interface  86  by setting the crop type and vacuum levels and profile to be used by planter  10  during the planting operation. Operational systems are activated at step  104  to ready planter  10  for the planting operation. At step  106  controller  37  determines if the vacuum control system  70  of the present invention is activated, if not, method  100  proceeds to step  116 . If vacuum control system  70  has been activated then at step  108  controller  72  determines if frame position sensor  72  is indicating that planter  10  has been lowered in anticipation of the planting operation, if not, then method  100  proceeds to step  116 . If the planter has been lowered, then controller  72  determines if the ground speed of planter  10  has exceeded a predetermined ground speed (step  110 ), such as 5 miles per hour (8 km/h), if not, then method  100  proceeds to step  116 . 
         [0026]    Now, additionally referring to  FIGS. 4 and 5 , there are shown operating curves with vacuum levels depicted on the vertical axis and ground speed along the horizontal axis. If the ground speed of planter  10  is above the predetermined level (approximately 3 mph in  FIG. 4 , and 5 mph in  FIG. 5 ) then the selected vacuum level for the indicated ground speed is achieved by controller  72  altering the flow of fluid through valve  78  to alter the speed of fan  82  (step  82 ) so that the selected vacuum level is accomplished. The vacuum level produced by vacuum producing apparatus  84  may level off once the ground speed of planter  10  reaches another predetermined value of, for example, 10 mph (16 km/h). 
         [0027]    The present invention may use a linear change in vacuum as the ground speed changes as depicted in  FIG. 5 , a non-linear change as depicted in  FIG. 4 , or a piecewise linear change (not shown). It is contemplated that the adjustment of vacuum levels may be refined to alter the level by sections of row units, or by each row unit individually, perhaps by the use of further valves not shown. If the ground speed remains constant (step  114 ) then method  100  returns to step  112 . 
         [0028]    At step  116 , if the output of sensor  76  is equal to the base vacuum setting, then that setting is held at step  120  and the process largely repeats, say by returning to step  106 . If the output of sensor  76  indicates that a change is in order, then hydraulic control valve  78  is adjusted at step  118  to thereby alter the vacuum produced by fan  82 . 
         [0029]    The present invention addresses the issue of adjusting a planter&#39;s seed meter air force relative to a variable operating ground speed for systems dependent upon air for delivery of seed, either vacuum based or pressure based. Historically, planters were designed to operate effectively in a narrow band of speed ranges. Due to this narrow operating speed band, operator adjustments to air based seed metering systems, either pressure based or vacuum based, typically was performed infrequently and then typically only if the metering disk was changed or the seed being planted had significantly different physical properties in terms of size, shape, or density. 
         [0030]    Seed metering systems are capable of planting at high speeds and the integration of sensors  72 - 76  provide feedback for critical performance factors such as seed planting quality, seed spacing, row unit ground contact pressures, meter ride quality, allowing the operating of planter  10  over a much wider ground speed operating range as it transverses the field. It has been found that in most instances a proportionally higher vacuum level or air pressure is required relative to increasing ground speed for proper seed metering performance. This change is related to the increase in force required to attach a seed to a rotating disk as the rotating disk increases in rotational speed. 
         [0031]    In the prior art an operator would adjust the hydraulic flow control at the tractor or change a control setting via a cab mounted user interface device. For most modern day planters, this invention does not require a change in construction as most planters have on-board controllers and the necessary sensors needed to implement the present invention with the air systems being discussed. The area of change would be controller software based. 
         [0032]    It is also contemplated to use sensors/inputs that further improve performance, such as seed delivery performance values, and row unit ride quality. Seed types vary by size, shape, density, and planting populations, therefore, the incremental force needed with speed change would not always be the same. As such, the system must know what crop type is being planted. This value is typically a result of data that the operator inputs into the in-cab display unit  86 . The operator can also input the recommended air force target value based upon the seed type, seed size, and expected average ground speed, which is typically gleamed from the operator&#39;s manual and experience. Once entered, the on-board controller  72  selects the appropriate air force-ground speed performance curve (such as those represented in  FIGS. 4 and 5 ) from a predefined software configuration table for the associated crop type, having a minimum and maximum value not to exceed, regardless of ground speed. 
         [0033]    The operator user interface  86  provides for manual or automatic control of this feature. When in manual mode, the operator would have to initiate any change associated with ground speed changes. When the present invention is being carried out, in the automatic mode, the system looks for the implement work status signal. If the system is out-of-work, the last known value would be retrieved and used. If in-work is detected, controller  72  compares the current ground speed with the current air force value and compares the values to the predefined performance curve. If the values do not match, controller  72  sends out a signal to adjust the hydraulic drive by altering valve  78  to thereby either increase of decrease the air force in order to approximately match the desired values. The system  70  continues to monitor this state and make any necessary changes to match current conditions. 
         [0034]    In some cases and crop types, the predefined performance curve may not yield maximum performance. A further enhancement of the system  70  is to also monitor seed delivery sensor values that are reporting seed singulation and seed multiples, hereafter known as seed performance values. Seed metering performance can be enhanced if the seed performance values are known. If the values are present and operation is in automatic mode, controller  72  adjusts the air force to the performance curve and then check the seed performance values. If seed skips is high, indicating seed is not adhered to the metering disk, additional air force would be provided until the seed skip value is acceptable. Conversely, if seed multiples are high, indicating more than one seed is being adhered to openings in the seed disk, the air force would be reduced from the performance curve value until the multiple value was at acceptable limits. Checks would be on-going whenever the machine is in the in-work mode of operation. 
         [0035]    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.