Method for determining agricultural bale weight

A method is provided for determining the weight of an agricultural bale that compensates for un-level terrain such as hillsides. The method uses an empty baler tare weight and a full baler weight to determine a raw bale weight. The cosine of the slope upon which the baler sits is then calculated based upon the empty baler weight as it sits and the empty baler tare weight. The cosine of the angle of slope and raw bale weight are then used to determine an actual bale weight. Further steps are provided for compensating in the tare weight of the baler for the weight of wrapping material consumed in the formation of each bale.

FIELD OF THE INVENTION

The present invention relates to agricultural balers. More particularly, the invention relates to agricultural balers having bale scales and/or load cells for weighing bales. Specifically, the invention relates to a method of determining the weight of agricultural bales that accounts for differences in indicated weight due to hillsides, slopes etc.

BACKGROUND OF THE INVENTION

It is known to equip agricultural round balers with load cells or other types of scales to determine the weight of the bale. The problem with all known systems is that they do not provide an accurate bale weight when the baler is sitting on an incline such as a hillside. The reason for this problem is that the load cells that are typically mounted in the hitch and/or axles, deflect in proportion to the normal force which is perpendicular to the axle. When the baler is resting on a horizontal plane, the “normal force” and the “force of gravity” are both perpendicular to the axis of the load cell. In this case, the load cells provide an accurate measurement of the bale weight. However, when the baler is paced on a hillside, the “normal force” and the “force of gravity” are not aligned i.e. the “normal force”=(force of gravity)*COS(slope angle). Because of this, the bale weight is underestimated.

While it is possible to mount an inclinometer on the baler to measure the angle of the slope to account for this effect, doing so adds extra cost and complexity into the system.

Accordingly there is a clear need in the art for a method of determining an accurate weight of an agricultural round bale regardless of the angle of inclination.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a method of determining a weight of an agricultural bale formed in a round baler.

It is another object of the invention to provide such a method of determining a weight of an agricultural bale formed in a round baler wherein an accurate weight can be determined regardless of the angle of inclination of the baler.

A further object of the invention is to provide such a method that further accounts for the weight of twine or wrapping material and or preservative when determining the weight of a bale.

Another object of the invention is to provide such a method that does not require additional hardware and does not add additional complexity to the baler.

Yet another object of the invention is to provide such a method that is compatible with known agricultural baling equipment and techniques.

These and other objects of the invention are attained by a method for determining the weight of an agricultural bale formed in a baler comprising the steps of: determining an empty baler tare weight (Wt) while the baler is on a level surface; forming a bale in the baler; determining a full baler weight of the baler and completed bale (Wf); calculating a raw bale weight (Wr) wherein Wr=Wf−Wt; ejecting the bale from the baler and determining an empty baler weight (We); calculating a cosine of an angle of a slope upon which the baler sits (COS A) wherein COS A=We/Wt; and, calculating an actual bale weight (Wa) wherein Wa=Wr/COS A.

Further objects of the invention are attained by a method for adjusting a tare weight of an agricultural baler to compensate for a reduction in a weight of wrapping material consumed in the formation of a bale comprising the steps of: determining an initial tare weight of an empty baler (Wt); determining a specific weight of a wrapping material (Wwrap) being used in the baler in one of unit weight per unit area for net/film and unit weight per unit length for twine; determining a material width (Mw) if Wwrapis in unit weight per unit area; determining a completed bale diameter (Bd); determining a number of wraps (Nw) of wrapping material used on the bale; calculating a weight of wrapping material consumed in the bale (Wn) wherein one of, Wn=*(Bd/2)2*Mw*Nw*Wwranfor net/film and Wn=*(Bd/2)2*Nw*Wwrapfor twine; calculating a new empty baler tare weight (Wt′), wherein Wt′=Wt−Wn; and, adjusting Wtto equal Wt′ prior to a start of a new bale.

In general a method is provided for determining the weight of an agricultural bale that compensates for un-level terrain such as hillsides. The method uses an empty baler tare weight and a full baler weight to determine a raw bale weight. The cosine of the slope upon which the baler sits is then calculated based upon the empty baler weight as it sits and the empty baler tare weight. The cosine of the angle of slope and raw bale weight are then used to determine an actual bale weight. Further steps are provided for compensating in the tare weight of the baler for the weight of wrapping material and/or preservative consumed in the formation of each bale.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now toFIGS. 1 and 2it can be seen that a round baler is generally designated by the number10. The baler10is conventional in its arrangement and includes a main frame12supported on a pair of ground wheels14. A draft tongue16has a rear end joined to the frame12and has a forward end defined by a clevis arrangement18adapted for being coupled to a towing vehicle (not shown). A pair of upright side walls20are fixed to the main frame12and define forward regions of opposite side walls of a baling chamber. Mounted for pivoting vertically about a horizontal pivot arrangement22located at an upper rear location of the side walls20is a discharge gate24including opposite upright side walls26, which define opposite sides of a rear region of the baling chamber. A gate cylinder arrangement (not shown) is coupled between the main frame12and the opposite side walls26of the discharge gate24and is selectively operable for moving the discharge gate24between a lowered baling position and an opened discharge position. The baler10is of a variable size chamber design and thus comprises a plurality of longitudinally extending side-by-side belts28supported on a plurality of rollers30(only a few of which are shown). A bale forming chamber is defined by the sidewalls20,26, the rollers30and the belts28.

As mentioned previously, the baler10illustrated is a variable chamber design, wherein crop is rolled up in a spiral fashion in a nip formed between oppositely moving adjacent loops of belts28. The space between adjacent loops of belts28grows as the forming bale B grows larger. Accordingly, a belt tensioning device32is provided to take up slack in the belts28as needed. Thus the position of the tensioning device32, at any given time, is an indication of the size of the bale B at that time. A bale diameter sensor34in the form of a potentiometer is affixed to the pivot point of the tensioning device32and thus provides an electrical signal correlating with bale diameter to an Electronic Control Unit (ECU)36. The ECU36is provided for electronically controlling and monitoring a number of functions of the baler10. For example, the ECU36, in addition to monitoring bale size and other functions, can further be adapted for triggering a twine or wrapping cycle, opening the discharge gate, initiating bale discharge, controlling the application of preservative to the bale and for communicating crop moisture content and other information to the operator.

In its general operation the baler10is drawn through a field by a prime mover (not shown) attached to the tongue16. Crop material38is fed into a crop inlet40of the bale forming chamber from a windrow of crop on the ground by a pickup42. In the baler10, the crop material38is rolled in spiral fashion, as described above, into the cylindrical bale B. Upon completion, the bale B is wrapped with twine, net wrap or other appropriate wrapping material from a wrapping arrangement44and is discharged by actuation of gate cylinders that open the gate24permitting the completed bale B to be discharged from the baler10onto the ground.

With continuing reference toFIGS. 1 and 2, it can be seen that the baler10is further provided with one or more load cells46for sensing a weight of the bale during and after bale formation in the baling chamber. More particularly, the baler10can be provided with a load cell46A on the tongue16of the baler10adjacent to the clevis18. Further, as shown inFIG. 2, the baler10can be provided with load cells46B and46C which are interposed between the baler frame12and the axle48. Accordingly, the load cells produce a signal varying with their deflection, thereby providing an indication of bale weight. These signals are transmitted by a wired or wireless connection to the ECU36.

Round balers of the type described above are unique in their operation in that the bale chamber is filled with hay to form a bale, and when the bale is finished the chamber is emptied. Because of this, it is possible to calculate the true weight of the bale on hillsides without the need and expense of a inclinometer. The novel methods for calculating the true weight of the bale by accounting for inclination are set forth in more detail below.

It is first necessary to determine, in advance, the weight of the empty baler while the baler is on a level surface. This EMPTY BALER TARE WEIGHT (Wt) is then recorded in the ECU. Upon the completion of a bale, the baler is again weighed to determine the weight of the baler plus the weight of a full bale. It should be noted that the completion of the bale can be sensed by monitoring the gate position through the use of appropriate sensor. For example when the gate is first opened the bale, still on board the baler, is complete. When the gate is closed again the bale has then been ejected and the baler is empty. This FULL BALER WEIGHT (Wf) is also recorded in the ECU. The ECU can then determine the RAW BALE WEIGHT (Wr) by subtracting Wtfrom Wf. Then Wris also recorded in the ECU. The full bale is then ejected from the baler and the baler is weighed again to determine the EMPTY BALER WEIGHT (We) as the baler sits, which is also recorded in the ECU. The ECU then determines the COSINE OF THE SLOPE (Cos A) or angle of inclination by dividing Weby Wt, both of which were previously stored in a memory of the ECU. The ACTUAL BALE WEIGHT (Wa) is then determined in the ECU by dividing Wrby Cos A. Then Wacan be communicated by the ECU to the operator by means of an appropriate display device.

The steps for the logic employed by the ECU in determining the actual bale weight are illustrated in the flow chart ofFIG. 3. More particularly, after the start at301the empty baler is at302tared on a level surface to determine Wtand Wtis then stored in the ECU. Once the Wtvalue has been determined and stored it should not change until such time as the baler is modified in some way as to change its tare weight. However, it is recommended that in order to reduce error due to extraneous factors such as accumulation of debris etc. the baler should be re-tared periodically, for example, approximately every twenty bales. At303the baling process is commenced. At304the logic queries whether the bale is complete. If at304the answer is no, then the logic loops until such time that the answer is yes. If at304the answer is yes, then the full baler is weighed at305to determine Wf, and Wfis then recorded. Next at306the ECU calculates and records Wr. At307the bale is ejected from the baler and the baler is re-weighed to determine and record We. Next at308the ECU calculates and stores Cos A. Then the ECU calculates and stores Waat309. At310the ECU communicates Wato an operator display prior to the end at311. Thus it is possible to determine an actual bale weight wherein the inclination is compensated for without the need for additional hardware such as an inclinometer.

On round agricultural balers some twine or net/film material is necessarily consumed for each bale. Thus the EMPTY BALER TARE WEIGHT (Wt) which includes the weight of the spools of twine or rolls of net/film material is reduced with each completed bale, by the weight of the net or twine applied to the bale. This weight reduction is directly proportional to the amount of net or twine consumed, which is, in turn, related to the bale diameter and number of wraps of twine or net applied to the bale. Thus if it is desired to account for this reduction in tare weight it will be necessary to re-tare the baler from time to time. This can be done periodically during the baling operation if conditions permit, e.g. if the baler can be reweighed on a level surface. However, it is possible to account for this reduction in tare weight each time a bale is made by subtracting the weight of the net or twine applied to each bale from Wteach time a bale is made. The method for determining the NEW EMPTY BALER TARE WEIGHT (Wt′) follows. First it is necessary to weigh the baler on a level surface as described above to determine an initial (Wt). It is also necessary to record in the ECU the SPECIFIC WEIGHT OF THE WRAPPING MATERIAL (Wwrap) in lbs/ft2, or for twine, in lbs/ft, and the WRAPPING MATERIAL WIDTH (Mw) based upon the type of wrapping material being used. It should be noted that on balers using twine systems the width of the wrapping material is not applicable. Then, when a bale is complete, the BALE DIAMETER (Bd) is determined from the bale diameter sensor. (Bd) is then recorded in the ECU. The NUMBER OF WRAPS (Nw) of net or wrapping material used is also determined and recorded in the ECU. It should be noted that for twine systems, Nwshould include the total number of wraps for all twines used across the baler. Nwcan be determined for example, through the use of appropriate sensors or by calculating the RPM of the bale and the time in which the wrapping mechanism is activated, as is well known in the art. The WEIGHT OF THE WRAPPING MATERIAL CONSUMED BY THE BALE (Wn) can then be calculated in the ECU by one of the following equations:for bales having net or wide wrapping material:
Wn=*(Bd/2)2*Mw*Nw*Wwrapfor bales having twine:
Wn=*(Bd/2)2*Nw*Wwrap

The NEW EMPTY BALER TARE WEIGHT (Wt′) is then determined by subtracting Wn, calculated above, from Wt. Then Wtcan be adjusted to equal Wt′ in the ECU and so on for each subsequent bale.

The above method is shown as a flowchart inFIG. 4. After the start at400the baler is weighed on a level surface to determine an initial Wtat401. At402Wwrapis input into the ECU. Similarly Mwis input at403. Upon completion of a bale, Bdis determined and recorded in the ECU at404. Then at405the number of wraps of material Nwis determined and recorded. At406the ECU calculates Wn. The new empty baler tare weight Wt′ is then calculated at407. At408the initial tare weight Wtis adjusted to equal the new tare weight Wt′ prior to the end at409.

A similar method can be used to calculate a new tare weight for the baler due to a reduction in weight as a result of the consumption of preservative used in the production of a bale. In this case the logic can be adjusted to utilize a weight per unit volume of preservative and then determining via appropriate sensors or other means the volume of preservative used for each bale. Once the weight per unit volume and volume consumed are known the tare weight can further be adjusted to compensate for the reduction.

The logic outlined inFIGS. 3 and 4are integrated in the flowchart ofFIG. 5wherein the complete logic for weighing a bale while compensating for slope and allowing for tare weight reduction due to material usage is illustrated. More particularly, after the start at500the empty baler is, at501, weighed on a level surface to determine Wtand Wtis then stored in the ECU. At502Wwrapis input into the ECU. Similarly Mwis input at503. At504the baling process is commenced. At505the logic queries whether the bale is complete. If at505the answer is no, then the logic loops until such time that the answer is yes. If at505the answer is yes, the full baler is weighed at506to determine Wf, and Wfis then recorded. Then Bdis determined and recorded in the ECU at507. At508the number of wraps of material Nwis determined and recorded. Next at509the ECU calculates Wn. At510the ECU calculates and records Wr. At511the bale is ejected from the baler and the baler is re-weighed to determine and record We. Next at512the ECU calculates and stores Cos A. Then the ECU calculates and stores Waat513. At514the ECU communicates Wato an operator display. The new empty baler tare weight Wt′ is then calculated at515. At516the initial tare weight Wtis adjusted to equal the new tare weight Wt′ prior to the start of a new bale.

In view of the foregoing it should now be apparent that it is possible to determine an accurate bale weight that compensates for hillside operations and further compensates for wrapping material usage, without the need for additional hardware in the form of inclinometers etc. It should also be apparent that the above described methods are compatible both with many known round baler types and conventional baling techniques.

Thus it can be seen that the objects of the invention have been satisfied by the structure presented above. While in accordance with the patent statutes, only the best mode and preferred embodiment of the invention has been presented and described in detail, it is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly and legally entitled.