Abstract:
A large round baler equipped with moisture sensing apparatus and a bale scale to improve information useful in baling and using bales. Moisture sensing begins after the bale reaches a predetermined diameter. A history of bale weights is used to estimate how much tension to apply to a belt tensioner to achieve both a target bale weight and a target bale size.

Description:
TECHNICAL FIELD  
       [0001]    The principles disclosed relate to improvements to round balers used for harvest of agricultural crops. The invention relates particularly to a method and apparatus for determining a weight of a bale of hay after it is formed, a moisture content of the bale, projecting a size of a bale at a set point weight, and calculations and data display. 
       BACKGROUND  
       [0002]    Large, cylindrical balers have been on the market for a number of years. Typically, the forming of a bale is terminated according to a diameter criterion. Depending on the crop and its moisture level, the weight of bales and the dry matter content can vary widely, even in the same field. 
         [0003]    A variety of sensors are incorporated into a large, cylindrical bale baler in U.S. Pat. No. 5,622,104. In particular, the use of a bale size sensor is disclosed. Additional sensors are suggested for bale RPM, crop moisture, horsepower demands, belt tension, and bale weight. 
         [0004]    Wild et al. reported a hay yield monitoring system for round balers with strain gages on the tongue and axle of the vehicles, which provided a measure of the weight of the baler and the bale. They also added accelerometers to measure vertical accelerations during operation and determined stationary loads within 2% of actual weight. Measurements under dynamic conditions are still under investigation. (Wild, K., H. Auernahammer, J. Rottmeier, 1994. “Automatic Data Acquisition on Round Balers,” ASAE Technical Paper No. 94-1582, presented at 1994 ASAE International Meeting, Atlanta, Ga. December 13-16, 15 pp.) 
         [0005]    A cylindrical bale baler system was disclosed in U.S. Pat. No. 6,378,276. The system comprises an electronic evaluation unit for processing signals from displacement sensors and a pendulum, transmitting the bale weight to an output unit with which the data are displayed or stored, such as on a yield card. Additionally, a control device may control various baler functions. Further, a moisture sensor for crop material may be connected with the evaluation unit for an automatic conversion to weight of the dry mass of the big round bale. 
         [0006]    There is, therefore, a need for a cylindrical baling system providing a volume average of the moisture level, a bale weight for each bale, consistent bale weight and size, and an identification label, ultimately providing bale weight, moisture, baling date, and field location for each bale. 
       SUMMARY  
       [0007]    A general object of the present invention is to provide data for each bale made in a large cylindrical (big round) baling operation for decision making, display, archival, and automatic control. 
         [0008]    Parameters sensed by the present invention include bale diameter, bale weight, moisture content, and geographical location. 
         [0009]    Moisture measurements will be taken after a bale has reached a predetermined diameter. Readings will be available as volume averaged moisture content of the bale as the bale diameter increased from the predetermined value to the terminal value. 
         [0010]    Finished bales will be weighed before ejection from the baler. A history of recent bale weights will be stored and used to adjust future bale densities to achieve desired terminal weights and sizes. To effect varying densities, a variable fluid pressure relief valve is provided to the belt tensioner, thus the resistance of the tensioner arm to rotation away from the bale is variable. 
         [0011]    Various forms of identification with which to associate a particular bale with its data are available. A simple alphanumeric ID may be stamped in ink or paint on the bale or wrapping. A printout of an ID and/or bale data on a slip of paper or cardstock may be dropped between the crop material and the binding material. A Radio Frequency (RF) chip or chips may be incorporated in bale wrapping, twine, or simply dropped between the crop material and the wrapper. Other electronic chips may also be used, including transponders. Bale data may be stored on the electronic media, or only an ID, which may be cross referenced in archived data. 
         [0012]    An object of this invention is to provide volume-averaged moisture content readings of a bale beginning after a predetermined bale diameter has been achieved. Another object of this invention is to utilize bale size and weight histories to adjust a bale density to achieve both a terminal size and weight. Still another object is to provide an identification system for large round bales after they have been formed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0013]      FIG. 1  is a side elevation view of a round baler; 
           [0014]      FIG. 2  is a partial isometric view of a round baler; 
           [0015]      FIG. 3  is a side elevation view of a round baler with a partially formed bale; 
           [0016]      FIG. 4  is a side elevation view of a round baler with a fully formed bale; 
           [0017]      FIG. 5  is a rear elevation view of a round baler; 
           [0018]      FIG. 6  is a side elevation view of a round baler pulled by an agricultural tractor; 
           [0019]      FIG. 7  is a flow diagram of the process of the present invention; 
           [0020]      FIG. 8  is a flow diagram of a calculation for determining a volume averaged moisture content; 
           [0021]      FIG. 9  is a flow diagram of a calculation for determining bale dry matter; 
           [0022]      FIG. 10  is a plot of bale weight, W, versus fluid relief valve pressure, x; 
           [0023]      FIG. 11  is a flow diagram showing how bale weight and fluid relief valve pressure histories are used to determine a new relief valve pressure set point; 
           [0024]      FIG. 12  is a perspective view of a cylindrical bale with an ID marking; 
           [0025]      FIG. 13  is a perspective view of a cylindrical bale and an identifying page; 
           [0026]      FIG. 14  is a perspective view of a cylindrical bale with a transmitter attached to the bale wrap; 
           [0027]      FIG. 15  shows a length of twine bale wrapping material with transmitters attached at intervals; 
           [0028]      FIG. 16  is a schematic diagram of a first bale density pressure relief/control system; 
           [0029]      FIG. 17  is a schematic diagram of a second bale density pressure relief/control system; 
           [0030]      FIG. 18  is a schematic diagram of a coupling between the belt tensioner and a hydraulic damper; 
           [0031]      FIG. 19  is a flow diagram of information to an identifying page; and 
           [0032]      FIG. 20  is a flow diagram of information to a transmitter or transponder. 
       
    
    
     DETAILED DESCRIPTION  
       [0033]    With reference now to the various figures in which identical elements are numbered identically throughout, a description of various exemplary aspects of the present invention will now be provided. The preferred embodiments are shown in the drawings and described with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the embodiments disclosed. Any references, herein, to directions will be determined by facing in the direction of travel of the baler during normal operation. 
         [0034]    A cylindrical bale baler  100  is shown in  FIGS. 1-6 . Crop material  110  feeds into a bale forming chamber  120  where the crop material is rolled into a bale  310 . In the preferred embodiment, the baler  100  is outfitted with a tongue load cell  130  and axle load cells  510  at each end of the axle  210 . Signals from these load cells are combined to obtain a weight of the bale  310 . Additionally, at least one moisture sensor  140  is provided near a crop material inlet  150 . The moisture sensor  140  provides a signal proportional to the percentage by mass of water in the incoming crop material  110  as follows: 
         [0000]    
       
         
           
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         [0035]    In  FIGS. 1 ,  3 , and  4 , the baler  100  is shown lifting forage material  110 , inserting it through the inlet  150 , and forming a bale  310 . As seen especially in  FIGS. 5-6 , the baler is supported at three points: by right and left side wheels  220  and by a tongue  165 . The load cells  510  engaged to the axle  210  are shown in  FIG. 5 . The tongue load cell  130  is shown in  FIGS. 1 ,  3 , and  4 . The load cells are produced by Digistar® as PN 2.125 DA-21 Drawing no 403993. Each load cell  130 ,  520  will generate a signal that is proportional to the load supported at that point. The generated signal is transferred in any manner to a controller  620 . The method of communication illustrated in the present embodiment includes a wire connection via a wiring harness  630 . Wireless communication is an alternative. The controller  620  may be mounted on/in the tractor  610  or on the baler  100 . 
         [0036]    The large round baler is shown in perspective from the right rear corner in  FIG. 2 . The moisture sensor  140  is shown from the inside. The right wheel  220  has been removed. 
         [0037]      FIG. 6  illustrates a round baler  100  being towed by a tractor  610  in the normal fashion. 
         [0038]    A flow diagram of the process of gathering bale data is shown in  FIG. 7 . The bale  310  begins to form  700  by the introduction of crop material  110  into the baler  100 . As crop material  110  continues to be added to the bale  310 , the bale size, measured by the diameter, d, increases  705 . The baler system senses the diameter, d,  710 . The instantaneous diameter, d, is compared to a lower threshold diameter, d 0 , in a first comparator block  715 . If the instantaneous diameter, d, is less than the threshold diameter, d 0 , the bale is allowed to continue to grow  705 . If the instantaneous diameter, d, is greater than or equal to the threshold diameter, d 0 , the instantaneous diameter, d, is stored in d −1    720  and moisture readings are begun  725 . The bale diameter, d, continues to be sensed  730  and at increments of Δd  735 , the bale moisture content is volume averaged  740  (see  FIG. 8 ). The bale diameter, d, is compared to the terminal diameter, d T    745 , at which addition of crop material  110  is to be terminated. When the bale diameter, d, has reached the terminal diameter, d T , the bale  310  is bound  750 , weighed  755 , and ejected  760 . Binding can be accomplished in any way known in this art such as twine  1510  (see  FIG. 15 ) or netwrap. The present invention is not limited to any particular binding method or material. This process will usually be repeated until all the crop material  110  is baled, or until conditions are such that baling should be terminated, as is well known by those skilled in the art. 
         [0039]    Moisture measurement is made possible during baling by the pad  120  on at least one side of a baler as disclosed in U.S. Pat. No. 4,812,741 to Stowell and herein incorporated by reference.  FIGS. 1-4  and  6  illustrates one such moisture sensor  120  mounted on the left side panel. In the preferred embodiment, a moisture measurement is received by the controller  620  at intervals in time. As illustrated in the flow diagram of  FIG. 8 , the moisture content is displayed as a number between zero and one, and is calculated as: 
         [0000]    
       
         
           
             
               
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         [0000]    where M n  is the n th  moisture reading, d n  is the n th  diameter, and represents the diameter at the time of the n th  moisture reading, M n . The n th  moisture reading, M n , may be an average of the moisture readings taken while the bale diameter increased from d n-1  to d n , or it may be a single, representative reading taken during the growth of the bale from the diameter, d n-1 , to the diameter, d n . 
         [0040]    Knowing the moisture content of a finished bale, M, and the weight of the bale, W, the total weight of dry matter of the bale may be calculated as shown in  FIG. 9 : 
         [0000]      Dry Matter= W (1− M ). 
         [0041]    The plot in  FIG. 10  shows a set of bale weights plotted against the associated manipulated variable such as a pressure relief valve setting, frequency of intermittent valve opening, or duration of intermittent valve opening. These data are used in  FIG. 11  to determine a new fluid manipulated variable set point, x sp , to realize a target bale weight W target  in the next bale  310 . As more bales are completed and, thus, more data are available, the curve fit is improved. Curve fits are well known in the art and include polynomial fits using linear regression analysis, conventional spline fits, including linear interpolation, and Hermite cubic splines. These and other methods may be found in any of a plethora of numerical analysis textbooks, such as  Applied Numerical Analysis  2 nd  ed. by Curtis F. Gerald, Addison-Wesley Publishing Company, 1980, herein incorporated by reference. 
         [0042]    As shown in  FIG. 11 , the fluid manipulated variable set point, x sp , calculated by interpolation or extrapolation from bale histories, is used to adjust the manipulated variable through which hydraulic fluid must pass as the belt tensioner  170  rotates with the growth of the bale  310 . 
         [0043]    Systems for varying the resistance to pivoting of the belt tensioner  160  are shown in  FIGS. 16 and 17 . In  FIG. 16 , a hydraulic damper  1610  is connected by its shaft  1620  to the belt tensioner  160 . When the belt tensioner  160  is lowered, the hydraulic damper  1610  travels in its down direction, and hydraulic fluid passes through a check valve  1630 , which provides little resistance to flow. When the belt tensioner  160  is raised, the check valve  1630  disallows flow through itself. Hence, the hydraulic fluid must pass through an adjustable relief valve  1640 , by which the pressure at a pressure gage or transducer  1650  is limited at an upper value to the relief valve pressure set point, x sp . 
         [0044]    Therefore, as the bale  310  grows, the belt tensioner  160  applies a pressure to the hydraulic damper  1610 . In order, then, for the belt tensioner to pivot upwardly, the pressure at the pressure gage or transducer  1650  must reach the relief valve pressure set point, x sp . 
         [0045]    A control system to estimate the pressure relief valve setting to achieve the desired bale density applies the algorithm previously described and illustrated in  FIGS. 10 and 11  provides adjustment to the relief valve  1640  by any method and means well known by those of ordinary skill in the art. For instance, a stepper motor  1660  may be used to rotate a spring-force adjustment screw  1670 , the spring force ultimately providing the resistance to flow. 
         [0046]    A more involved pressure control system is schematically illustrated in  FIG. 17 . In this embodiment, a second pressure relief valve  1710  is provided. The second pressure relief valve  1710  has a lower set point than the first pressure relief valve  1640 , and only affects the flow if a solenoid valve  1720  is open. In this embodiment, the belt tensioner  160  is permitted to rise intermittently by intermittent opening of the solenoid valve  1720 . When the solenoid valve  1720  is closed, the pressure at the pressure gage or transducer  1650  is, at most, the value at which the first relief  1640  valve is set. Hence, the density of the bale may be controlled by the frequency and/or duration of the intermittent opening of the solenoid valve  1720 , and the relief valves  1640 ,  1710  do not require adjustability. In this case, the manipulated variable, x sp , of  FIGS. 10 and 11  is represented by a frequency or duration of opening of the solenoid valve  1720 . 
         [0047]    An additional embodiment is realized by measuring a value related to the belt tension in place of the manipulated variable, x sp . Such values include hydraulic system pressure, as illustrated in  FIGS. 16 and 17 , or a load cell reading, as depicted in  FIG. 18  which shows a load cell  1810  arranged to detect a force between the hydraulic damper  1610  and a mounting surface. 
         [0048]    Once moisture and weight data are collected for a given bale  310 , the bale may be provided with an identification number, symbol, transponder or transmitter. As shown in  FIG. 12 , an ID symbol or alphanumeric series  1210  may be painted or inked onto the outside of the bale wrap  1320  (see  FIG. 13 ) on the outside of the bale  310 . In  FIG. 13 , an identifying page  1310  made of paper, cardstock, plastic, fabric, or other material is inserted beneath the bale wrap  1320 . Such an identifying page  1310  may include the following data: GPS location, dry matter content, moisture content, weight, customer, operator, and baling date, as depicted in  FIG. 19 . The identification may be printed to the ID page  1310 , or a transmitter or transponder may be attached to the page. A transmitter or transponder  1410  is shown in  FIG. 14  attached to the bale wrap. In either of the cases where a transmitter or transponder  1410  is used, the transmitter or transponder  1410  may have the bale data, such as GPS location, dry matter content, moisture content, weight, customer, operator, and baling date, written to it, as depicted in  FIG. 20 , before the bale  310  is ejected from the baler  100 . Alternatively, the transmitter or transponder  1410  may only contain a unique ID that is correlated to the data stored in the baler&#39;s control system  620 . At a later date, the ID stored on the transmitter or transponder  1410  may be read in the field and the data found in a lookup table on a personal computer, for instance. Note that both netwrap and twine  1510  may be manufactured with transmitters or transponders  1410  preattached at predetermined intervals, as shown in  FIG. 15 , or the attachment may be done in the baler  100 . 
         [0049]    With regard to the forgoing description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the size, shape and arrangement of the parts without departing from the scope of the present invention. As used herein, the term “netwrap” is intended to include all sheet-type wrapping materials including tackified plastic materials and untackfied plastic materials. The term “bale wrap” as used herein is intended to include sheet-type bale wrapping materials as well as twine. It is intended that these specific and depicted aspects be considered exemplary only, with a true scope and spirit of the invention be indicated by the broad meaning of the following claims.