Abstract:
A baler for agricultural material including a reciprocating plunger that compresses crop material in a channel into flakes which are stacked to provide a bale length of the desired size. The baler is towed from and powered by a steerable tractor having an operator display. The channel receiving the plunger has right and left walls which support star wheels having points projecting into the channel for the flakes and bale. The relative movement of the bale from right to left is determined and indicated to the operator of the vehicle to steer right, left or straight to ensure that bales have thickness that is uniform across their width.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an agricultural baler, and, more particularly, to a system and method for sensing the shape of bales. 
     BACKGROUND OF THE INVENTION 
     A plunger type hay baler includes a frame that is hitched to a tractor and is configured to receive crop material, such as hay or straw, into a pressing cavity in which the crop material is pressed and formed into a bale. The baler includes a loading mechanism in which the crop material is collected from the ground, which is then routed into the pressing channel in a manner that is synchronous with a plunger. The plunger moves in a reciprocating manner in the pressing channel and encounters each new segment (flake) of crop material that is moved into the channel for compacting into a bale. After a sufficient amount of crop material has been compressed in the pressing channel, a twine threading mechanism inserts twine through a portion of the compressed material and the twine is then tied to complete the binding of the bale. The bale then proceeds further through the pressing channel and is ejected from the baling machine. 
     The shape of the bale in a baling device is important in determining the appropriate length of the bale and rectangularity for the purpose of storing, stacking and transporting. Current systems attempt to determine bale shape and length by sensing pressure forces that are reaction forces exerted against the plunger, and associated mechanism used to compress the flakes. When the force exceeds a given level, the bale is determined to be an appropriate length and then the subsequent processes are initiated. 
     The problem with this device, however, is that the pressure sensing to determine length of the bale does not occur until the last group of flakes enters the channel in which they are compressed. As a result, flakes can be entered into the chamber that have variable thickness from side to side so that instead of rectangular flakes forming the ultimate bale there may be misalignment between one side and the other. Such a malformation can have an impact on the ability to stack the resulting bales and/or to transport them. 
     Accordingly, what is needed in the art is a means and method for dynamically and effectively sensing the shape of a bale with an accurate measurement. 
     SUMMARY 
     The present invention provides dynamic and effective sensing of the shape of a bale. 
     The invention, in one form, is directed to a bale shape sensing system including a channel having left and right walls for receiving crop material. A plunger reciprocates in the channel to sequentially compress flakes of crop material into bales. Right and left devices arc mounted respectively on the right and left walls of the channel for measuring relative movement of the flakes whereby the shape of a bale is sensed. 
     The invention, in another form, is directed to an agricultural harvesting device comprising a steerable vehicle for traversing an agricultural field over a row of cut crop material. A baler is movable with the vehicle over the field and the baler has a channel with right and left walls for receiving crop material. A plunger is mounted for reciprocating movement within the channel for compressing crop material into flakes which are stacked to produce a completed bale. Right and left devices are respectively mounted in the right and left walls for determining movement of the right and left ends of the flakes relative to the right and left walls. A control mechanism receives signals from the relative motion devices for generating a signal indicating directional movement to the right, left or straight and a device has an operator display for indicating to the operator which direction to traverse to produce uniformly shaped bales. 
     The invention, in still another form, is a method of harvesting material with the steps of entering the crop material into a channel bounded by left and right walls. The agricultural crop material is compressed by a reciprocating plunger to produce discrete flakes. Subsequent agricultural crop material is compressed to produce stacked flakes. The movement of the right and left ends of the flakes relative to the right and left side walls is sensed to determine the shape of the bale including a series of stacked flakes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1  is a side view of a tractor and baler system utilizing an embodiment of the plunger of the present invention; 
         FIG. 2  is a plan view shown in schematic fashion of the baler system of  FIG. 1 ; 
         FIG. 3  is a plan view of the baler of  FIGS. 1 and 2  showing formation of a bale of agricultural material; 
         FIG. 4  is a detailed perspective view of a component of a relative movement sensing component of  FIGS. 2 and 3 ; 
         FIG. 5  is a schematic depiction of an operator display incorporated in the baling device of  FIGS. 1-4 ; and 
         FIG. 6  is a chart indicating the sequence of steps shown in the method of  FIGS. 1-5 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrate 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 
     Referring now to the drawings, and more particularly to  FIG. 1 , there is shown an agricultural baling apparatus  10  including a tractor and a baler  14  that is driven by a power take off (PTO) shaft connected therebetween. Although shown as a component towed by and receiving power from a tractor  12  it should be apparent to those skilled in the art that the apparatus may be combined into a single self-propelled and steerable unit and still embody the present invention. 
     Referring now specifically to  FIGS. 2 and 3  a system of  FIG. 1  as shown in schematic fashion. The baler  14  shown by dashed lines is of the plunger type and for that purpose a plunger  20  is positioned within a channel  22  to reciprocate and in the process of reciprocation form agricultural product into rectangular segments called flakes  29 . Channel  22  is defined by right and left wall assemblies  24  and  26  respectively. Wall section  24  has an upstream portion  25  in which the plunger  20  reciprocates. Section  25  extends to and is integral with a wall section  28  connected to a downstream wall section  30  and angled inward to a vertex  36 . Wall assembly  26  has an upstream portion  27  also receiving plunger  20 . Wall section  27  connects with inwardly directed wall section  32  and outwardly directed wall section  34  joined at vertex  38 . The upper and lower walls for the channel  22  are not shown to simplify an understanding of the invention. The converging panels are inwardly extending panels  28  and  32  extending to the vertex  36  and  38  provide a narrowing channel in order to apply pressure to the flakes  29  making up bale  31  as later discussed. 
     The mechanism for reciprocating plunger  20  is not shown to simplify an understanding of the present invention, but in typical form, would be an eccentric crank mechanism receiving rotary power from the PTO  16  converted into reciprocating motion. In addition, the mechanism for feeding the crop material into channel  22  is not shown nor is the mechanism by which the resultant bales  31  are tied is omitted to facilitate an understanding of the process. 
     Referring now to  FIG. 3 , there is shown a typical bale that is being processed. The plunger  20  compresses crop material into what is known in the art as individual flakes  29  having a thickness determined by the degree to which the plunger compresses the loose material. The height and the width of the flakes  29  is determined generally by the width and height of the channel  20 . As is apparent in  FIG. 3  the plunger  20  forms successive flakes  29  which are stacked end to end as they move through the channel  22 . The amount of material that comes into the baler  14  is determined by the distribution of the material coming into channel  22  and is, to some extent, determined by the relationship of the tractor and baler relative to rows of agricultural material that have been precut. As stated above, the reciprocating motion of the plunger  20  forces the flakes  29  towards the vertex  36  and  38  of the channel  22 . In the stack of flakes  29  towards the left of  FIG. 3 , the bales have been secured by twine through an appropriate mechanism to result in a bale  31 . As is apparent in  FIG. 3 , some of the flakes  29  may have variable thickness from right to left in the channel  22 . Heretofore, the length of the bale has been determined by reaction forces on plunger  20  or on the gear box driven by the PTO  16  so that only a gross measurement of the length of the bale  31  is determined. In the prior art, there is no capability of determining right to left variations in the thickness of the flakes  29 . 
     In accordance with the present invention right and left devices  40  and  42  are provided to determine movement of the flakes  29  relative to the right and left wall members  24  and  26  so as to indicate which side has a greater thickness than the other. As herein illustrated, the devices  40  and  42  are shown in  FIG. 4  as including a star wheel  52  journaled for rotation in a frame  48  which is affixed to the respective side walls by screws  50  and which extends into channel  22  through a slot  56  and the respective side walls. The star wheels  52  have individual points  54  that project into the channel so that the star wheels  52  rotate in response to movement of the flakes  29  relative to the walls of the channel  22 . A counter  58  is shown mounted to detect and provide a signal relative to the rotation of the star wheel  52 . The signal thus generated is connected via lines  60  or  62  to an ECU  64  which, in turn, is connected to a display  68  via line  66 . The number of points  54  and their projection into the channel  22  through slot  56  is selected so as to provide an optimum and accurate measurement of relative movement. In addition, the devices  40  and  42  are positioned downstream of the vertex  36  and  38  where the channel  22  diverges so as to prevent reverse rotation of the devices  40  and  42 . This is because any reverse movement of the crop material is minimized, if not eliminated. The display  68  may take a number forms but, as illustrated, is a display having right facing chevrons  70  and left facing chevrons  72 . In terms of operator input, the number of chevrons activated to one side or the other, herein illustrated as to the right, indicates to the operator that the tractor  12  must be guided towards the right to maintain a consistent thickness for the bale. When the operator is directed to traverse a straight path, the innermost opposed chevrons  70  and  72  provide a diamond to indicate to the operator the appropriate straight path. While a display of either LED or LCD indicia as chevrons is illustrated, it should be apparent to those skilled in the art that many other forms of a display can be used to guide the operator. 
     To summarize the method utilized in the operation of the baler  14 , the relative movement of the flakes from the left side relative to the right side is determined by the counters  58  and through internal electronics converted into a signal directing the operator to either turn to the left or turn to the right or traverse a straight path. The number of activated chevron elements indicate to the operator the degree to which the tractor must be turned to traverse the center of the row of agricultural material. 
     The detailed implementation of the method is illustrated in  FIG. 6  in which the elements of the control system are shown in block fashion. In step  74  there is a system startup and stored values from the EEprom for left hand and right hand counts, previous bale length, first, second and third stored values of the correction indicators (chevrons) are loaded. In step  76 , it is determined whether a flake has been sent and if it has in this indicates that a flake has been entered into the channel. In step  78  it is indicated where whether the plunger  20  has been sent which begins the compression process of the flakes. In step  80 , both the left hand and right hand flake counts are determined and the difference between the counts is determined in step  82  so that in step  84  the drive direction either right, left or straight is indicated on display  68 . In step  86 , the drive direction is rounded to the nearest arrow value and the display  68  is updated. In step  88 , the bale length is calculated by determining the number of counts for the left hand adding to the counts of the right hand divided by two. When the appropriate bale length is reached, the tie cycle is initiated in step  90  which causes the twine  44  to be automatically secured around the completed bales  31 . At that point, the left hand and right hand counts are summed to zero and the cycle repeated. 
     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.