Abstract:
A large round baler is provided with a weighing arrangement for the detection of the weight of a cylindrical bale. The weighing arrangement is arranged to detect the force that a cylindrical bale applies to a support element located in the baling chamber and movable relative to the bale for supporting substantially the entire weight of the bale during discharge of the bale from the baling chamber. So that a true weight reading is obtained, the side pressure exerted on the bale by the side walls is released before the weight measurement takes place. Additionally, an inclination sensor is provided for sending information to an evaluation arrangement which makes an adjustment in a sensed weight to account for any engagement of the bale with the sides of the baling chamber due to side-to-side inclination.

Description:
FIELD OF THE INVENTION 
   The invention concerns a large round baler with a weighing arrangement for the detection of the weight of a compressed cylindrical bale. 
   BACKGROUND OF THE INVENTION 
   EP 1 034 695 A describes a large round baler that is equipped with a roll-out arrangement configured as a weighing arrangement for the finished cylindrical bale. The roll-out arrangement is configured as an inclined plane arranged underneath the rear flap that can be flipped upward, over which the bale leaves the large round baler and reaches the ground of the field. The weighing arrangement detects the weight of the bale in that the force applied by it to the roll-out arrangement or the acceleration of the bale during its rolling off the roll-out arrangement is measured by sensors. 
   In this large round baler, it is seen as a disadvantage that elements essential to the function of the weighing arrangement are arranged unprotected on the outside of the large round baler, so that they are exposed to the environmental effects of the surroundings and can easily be damaged. 
   SUMMARY OF THE INVENTION 
   The problem underlying the invention is seen in the need to make available an improved large round baler with a weighing arrangement. 
   This problem is solved according to the invention by the teaching of patent claim  1 , where the further patent claims cite characteristics that further develop the solution to great advantage. 
   It is proposed that a support element in the baling chamber of the large round baler be equipped with a weighing arrangement. A cylindrical bale produced in the baling chamber rests on the support element, so that the force applied by the bale to the support element can be detected by the weighing element and utilized for the determination of the weight or mass of the cylindrical bale. 
   In this way, the result is that the weighing arrangement is arranged in the interior of the large round baler protected against environmental effects and unintended damage. 
   It would fundamentally be conceivable that the large round baler be configured in such a way that the entire weight of the cylindrical bale rests on the support element, so that the weight applied to it corresponds to the weight of the cylindrical bale. However, such an arrangement would be relatively costly, since as a rule, the cylindrical bale is supported by several elements whose support forces must be determined individually or together. Therefore, in a preferred embodiment, the support element can be moved relative to the bale. 
   In actual fact, the cylindrical bale can move relative to the support element, particularly during the ejection, for example, by rolling, where the weight is detected by the weighing arrangement. On the basis of the course of the force detected by the weighing arrangement, an evaluation arrangement determines the weight of the bale. Alternatively, or in addition, the support element can move relative to the large round baler and thereby the cylindrical bale. During this movement, there is preferably a point in time at which the cylindrical bale rests entirely, or almost entirely, on the support element. The force acting at this point in time corresponds to the weight of the bale. 
   A support element of this type is appropriately actively driven by a drive, for example, an electric or hydraulic motor. In order to be able to detect the weight of the bale, the movement of the support element is performed preferably about a pivot axis that extends at least approximately through the central axis of a finished cylindrical bale. However, the pivot axis may be located before or behind this central axis, or underneath or above it. Hence, the support element extends along the underside of the cylindrical bale. 
   During the formation of the cylindrical bale, the support element is located preferably at its underside, ahead of the axis of the cylindrical bale in the direction of operation, in a bale forming position, in order to support the formation of a core of the bale. From this initial position, it can be repositioned in correspondence with the increase in the size of the cylindrical bale being formed. Before the ejection of the cylindrical bale, the support element is moved into a bale ejection position, in which the bale no longer rests on the support element. During the intervening movement, a partial region of the underside of the bale is crossed and its weight is detected. In the ejection position, the support element is located, for example, above the ejection end of the baling chamber of the large round baler. In another embodiment, the support element could be moved forward out of a bale forming position, in which it is located behind the axis of the bale in the direction of operation. Simultaneously, an impulse is delivered to the cylindrical bale that rolls it to the rear out of the baling chamber. 
   In order to avoid falsifying the result of the measurement by friction forces between the side walls of the baling chamber and the cylindrical bale, it is useful to move the side walls of the baling chamber apart before the ejection of the cylindrical bale and the detection of its weight. This movement is performed preferably by the drive that also moves the support element. But it would also be conceivable to use a separate drive, for example, a hydraulic cylinder, particularly if the support element is stationary. The outward movement of the side walls is also useful for the reduction of the friction forces during the ejection of the bale. After the ejection of the bale, the side walls are again moved towards each other for the formation of a further bale. 
   In order to attain sufficiently accurate measurement values for the weight of the cylindrical bale, (for example, for the geo-referenced yield mapping) it may be appropriate to operate an evaluation arrangement for the correction of the measured weight in order to consider, for example, a possible inclination of the large round baler from the horizontal, that would lead to the cylindrical bale making contact with the side walls, or baling elements lying upon the cylindrical bale or lying between the cylindrical bale and the support element. 
   The support element upon which the cylindrical bale rests, is preferably a pulley or a roll, whose axis extends parallel to the axis of the cylindrical bale. In order to avoid friction, it is appropriately free to rotate about its axis. Several pulleys or rolls could also be used. 
   The weighing arrangement includes preferably a measurement cell, known in itself, that is located in a positive lock between the support element and the frame of the large round baler. But any other means can be used that are appropriate for the detection of the weight of the cylindrical bale. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings show an embodiment of the invention that shall be described in greater detail in the following. 
       FIG. 1  shows a schematic left side view of a large round baler incorporating the present invention, with the baling chamber shown in a closed position. 
       FIG. 2  is a schematic rear view of the large round baler shown in  FIG. 1 . 
       FIG. 3  is a view like that of  FIG. 1 , but showing the baling chamber in an open position. 
       FIG. 4  shows a graph of the measured support forces over a period of time. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1 and 2 , there is shown a large round baler  10  including a frame  12 , a chassis  14 , a towbar  16 , a take-up arrangement  18 , rolls  20 ′– 20 ′″, baling elements  22 , a tensioning arrangement  24 , side walls  26 , a baling chamber  28 , pivoting parts  30 , and a pressure arrangement  32 . 
   In the embodiment shown, the large round baler  10  is equipped with a baling chamber  28  of variable size, but may also be equipped with a baling chamber  28  whose size cannot be varied. In the baling chamber  28 , harvested crop taken up from the ground is formed into a so-called cylindrical bale which presses against the side walls  26  with its end faces. 
   The frame  12  can be seen particularly well in  FIG. 2  and is composed of a welded and/or bolted assembly to which all components of the large round baler  10  are fastened, that is supported on the chassis  14  and that can be connected by means of the towbar  16  to a towing vehicle, not shown. The frame  12  carries, among other items, sheathing components, not shown, several of the pulleys  20 ′– 20 ′″, the side walls  26 , and the pivoting parts  30 . The frame  12  encloses in a wide area the region surrounded by the side walls  26  and the baling elements  22 . 
   The chassis  14  consists of an axle and wheels, not described in any further detail, on which the frame  12  rests. The towbar  16  engages the forward side of the frame  12  rigidly or adjustable in height. 
   The take-up arrangement  18  is configured in the usual manner as a so-called pick-up and connected to the frame  12  so as to be adjustable in height. The take-up arrangement  18  can be followed by a cutting arrangement, also known in itself. The take-up arrangement  18  takes up crop deposited on the ground and conducts it over a cutting arrangement that may be available further into the baling chamber  28 , in which it is formed into a cylindrical bale. 
   Several rolls  20 ′ are supported in bearings, free to rotate, on stationary axes in the frame  12 . Several rolls  20 ″ support the baling elements  22 . In particular, one of the rolls  20 ″ is mounted for movement against the force of a spring  24 , so that the baling elements  22  can deflect to accommodate the growing diameter of the bale. Still other rolls  20 ′″ can be pivoted on pivoting parts  30  about a pivot axis  34 . All rolls  20 ′– 20 ′″ extend parallel to each other and are configured sufficiently wide and arranged in such a way that the baling elements  22  can run over them and enclose the baling chamber  28 . Beside the rolls  20 ′– 20 ′″, rolls  36  are provided that are located above an inlet opening  38  in the baling chamber  28 . These rolls  36  operate as so-called starter rolls during the beginning of the bale forming process and on which a part of the weight of the cylindrical bale can be supported. 
   The baling elements  22  disclosed here are in the form of a plurality of relatively narrow belts, extending parallel to each other, that generally cover the baling chamber  28  across its width. In place of the relatively narrow belts, the baling elements  22  could be configured as bar-chain conveyors or as a single wide belt, as is also known practice. The baling elements  22  are endless and are brought into a circulating movement by a frictional engagement with at least one pulley  20 ′ that can be driven. In the region of the inlet opening  38 , the baling elements  22  form a bridge that forms itself into a loop that deflects inward with increasing amounts of harvested crop and that surrounds the forming cylindrical bale. The baling elements  22  are kept under tension by being conducted over the spring-loaded, movable roll  20 ″. 
   The tensioning arrangement  24  is configured in a known manner wherein the roll  20 ″ is guided on an arm, slide or the like against the force of a spring  24  and constantly maintains a loop of the baling elements  22  under tension. 
   As viewed in  FIG. 1 , the side walls  26  take the shape of a “D”, where the rear end region, at the right in  FIG. 1 , takes the shape of a semi-circle or bow that generally follows the line of the circumference of the finished bale, that is, it follows the line of a circular arc. Basically, the side walls  26  are configured as one-piece components, that is, they are not divided along an approximately central vertical plane, as in conventional large round balers. They may, however, be composed throughout of several parts.  FIG. 2  reveals that the side walls  26  maintain a not inconsiderable spacing to the frame  12 , and thereby can be deflected to the outside, as described below. The side walls  26  are configured so as to be stiff in bending by means of reinforcing struts  40 , where the reinforcing struts  40  can be bolted or welded on. According to  FIG. 1 , the reinforcing struts  40  extend in an approximate star-shape with respect to the pivot axis  34  and extend tangentially with small spacing to it, whereby the angularly adjacent struts  40  form a right angle with each other. On the basis of this, they enclose a four-sided chamber  42  in this embodiment. In their forward end region, the side walls  26  are connected, generally rigidly, to the frame  12 . Nevertheless, a slight pivoting movement is possible, starting from a position according to  FIG. 2  through a few degrees to the outside, due to the fact that the side walls  26  are either configured of a flexible sheet metal in their connecting region or are connected in a flexible connection, for example, on a flexible flange or are secured on spring-loaded screws. The connection of the side walls  26  to the frame  12  is performed generally along a more or less vertical line at the forward end of the baling chamber  28 . In the region of the pivot axis  34 , each side wall  26  is guided on an axle  44  which is rigidly fastened to the frame  12  and is simultaneously used as pivot axis for the pivoting parts  30 . 
   In contrast to the embodiment shown, the connection of the side wall  26  or the side walls  26  can also be performed along an upper line that is more or less horizontal or lightly inclined, with the result that the side walls  26  diverge in the downward direction when the cylindrical bale is ejected. 
   The baling chamber  28  is variable in its size and is bordered at the beginning, that is, when the baling chamber  28  is empty, by an approximately triangular cylindrical space between the take-up arrangement  18  and the baling elements  22  and at its sides by the side walls  26 . With increasing amounts of harvested crop supplied, the baling chamber  28  enlarges and finally assumes a cross section that follows the shape of the side walls  26  in the rear region. 
   In this embodiment, the pivoting parts  30  are equipped on each side with one or more arms  46  extending radially from the pivot axis  34 , and one or more transverse members  48  attached to its or their outer ends extending transverse to these. At the end of each transverse member  48  one of the rolls  20 ′″ is provided. The pivoting parts  30  are arranged with the radially inner end of each arm  46 , free to pivot, on the axis  34 . The position of the arms  46  is controlled by means of a drive  50  that includes a motor  52  and a flexible drive element  54 . Any other type of drive appropriate for rotating the pivoting part  30  may be provided. The pivoting parts  30  could also be driven synchronously by common pivoting drives or could be rigidly connected to each other, so that only a single pivoting drive is required. The motor  52  can be braked in each of its positions and retains the arms  46  correspondingly stationary. The output drive pulleys or sprockets  56  associated with each of the flexible drive elements  54  are supported in bearings concentric to each other and to the axis  34 , and are connected, fixed against rotation, in each case with one pivoting part  30 . The pivoting parts  30  are controlled in such a way that the forward pivoting part  30  is repositioned during the bale forming phase, in order to assist during the formation of the core of a bale, and that the forward pivoting part  30  assumes a lower position while the cylindrical bale is being formed, and both pivoting parts  30  assume an upper position when the cylindrical bale is ejected. The two end positions of the pivoting parts  30  are shown in  FIGS. 1 and 3 . 
   The large round baler described so far is essentially in all its details the same as that described in U.S. patent application Ser. No. 10/163,156, filed 04 Jun. 2002, whose contents is hereby incorporated into the present application. 
   The pressure arrangement  32  contains a cam member  58  defining an inclined path increasing in height in a direction away from the baling chamber side  26 , and a follower  60  (see the partial section to  FIG. 2  with a side view for this), and is used for and during the ejection of the cylindrical bale in order to reduce the pressure and thereby the friction of the side walls  26  on its end faces, so that the cylindrical bale can be unloaded more easily from the baling chamber  28 . 
   The cam member  58  is located on a circular arc extending concentric to the pivot axis  34  and is fastened to the outside of both side walls  26  (only the cam member  58  on the right side wall  26  is shown), where it would also be sufficient to provide only one cam member  58  only on one side wall  26 . In the present embodiment, the cam member  58  is formed by a bent steel part that is bolted to the side walls  26  and that is uniformly inclined from the wall  26  within the chamber  42 . 
   The follower member  60  is provided on the side of the arm  46  of the rear pivoting part  30  that faces the longitudinal center plane of the large round baler  10 , and is configured as a sliding surface. In order to minimize the friction, the sliding surfaces are lubricated. Alternatively, the follower member  60  could also be configured as a wheel, pulley, ball or similar rotating member. The follower member  60  is arranged in such a way that it describes a circular path about the pivot axis  34  upon a rotation of the pivoting part  30  and moves along the inclined plane defined by the cam member  58 . Preferably, the follower member  60  is in contact at all times with the cam member  58 . 
   Relative to the side wall  26 , the follower member  60  lies upon the highest elevation of the cam member  58  when the pivoting parts  30  are located in their lower end position, shown in  FIG. 1 , wherein the cylindrical bale can be produced. When the pivoting parts  30  are brought into their upper position, shown in  FIG. 3 , in which the cylindrical bale can be released from the baling chamber  28 , the follower member  60  is moved towards the lowest point of the inclined plane defined by the cam  58 . The difference between the highest and the lowest point may amount, for example, to approximately 20 to 50 mm. 
   As soon as a cylindrical bale has been formed in the baling chamber  28 , the pivoting part  30  is raised whereupon the side walls  26  move outward on the basis of the pressure existing in the baling chamber  28  that originates from the compressed harvested crop. As a result, the friction between the inner side of the side walls  26  and the end faces of the cylindrical bale is reduced and the latter falls out of the baling chamber  28  on the basis of the force of gravity, that is, it rolls over the bottom of the baling chamber  28  and a roll-out arrangement  70 , extending rearward from the chamber, onto the ground of the field. As soon as the cylindrical bale has left the baling chamber  28  and the large round baler  10  has been moved forward an amount sufficient for the pivoting part  30  to again be lowered, the pivoting part  30  is lowered so that the follower member  60  is moved along the cam member  58  to the highest point of the inclined plane and thereby presses the side walls  26  inward. 
   For yield mapping, the large round baler  10  is equipped with a position sensor  62  in the form of a GPS satellite antenna. This is connected with an evaluation arrangement  64  that in turn, is connected with a weighing arrangement that includes an inclination sensor  66  and four measurement cells  68 . The measurement cells  68  are inserted into the arms  46  (that are interrupted at the attaching point) and detect the force that the cylindrical bale applies to the rolls  20 ′″ that are used as bale support elements. Measurement cells known in themselves, strain gauges or any other desired force sensors could be used. In place of the two arms  46  shown in the drawing, the rolls  20 ′″ could also be connected by a lengthwise transverse member that is connected to an arm leading upward to the pivot axis  34  into each of which a measurement cell  68  is inserted. In such an embodiment, only two measurement cells  68  are required. 
   A bus line, (for example, a CAN bus), connects the position sensor  62  with the inclination sensor  66 , the measurement cells  68 , and the position sensor  62 . The evaluation arrangement  64  and the position sensor  62  could also be located on the towing vehicle, where corresponding software considers the offset in space between the position sensor  62  and the take-up arrangement  18 . During operation, the evaluation arrangement  64  produces a yield map in which the weight or mass of the cylindrical bales produced is recorded in geo-referenced terms. 
   While the harvested crop is being taken up from the field, a cylindrical bale is being formed little by little in the baling chamber  28 . Once it has reached the desired size that is detected by a sensor, the motor  52  of the drive  50  is activated by a control arrangement, as described above. Thereby, the pivoting parts  30  rotate counterclockwise, as viewed in  FIG. 1 , and the side walls  46  move outward. Initially, the cylindrical bale rests upon the pulleys  20 ′″ (with the sections of the baling elements  22  lying between them), while the contact force of the cylindrical bale on the remaining rolls  20 ′ or rolls  36  remains sufficiently low. The baling elements  22  are relieved of their tension, particularly by the pivoting movement of the pivoting parts  30  to the rear, and do not affect the measured values of the measurement cells  68 . Any friction of the cylindrical bale on the side walls  26  is eliminated as long as the large round baler  10  is sufficiently horizontal, since the side walls  26  have been repositioned to the outside. The forward roll  20 ′″, shown at the left in  FIG. 1 , rolls along the underside of the cylindrical bale and then along its rear side, until it comes to a stop at its upper side, as is shown in  FIG. 3 . The cylindrical bale is then free to roll down the ramp  70  to the ground. 
   During this process, the evaluation arrangement  64  detects the measurement values of the measurement cells  68 . An example of the measurement values of two measurement cells  68  on the left and the right side of the cylindrical bale as a function of time is shown in  FIG. 4 . With increasing time and pivot angle of the pivoting parts  30 , the measured values increase to a maximum and then decrease again. When the maximum is reached, the weight of the cylindrical bale rests only on the rolls  20 ′″, principally on the roll  20 ′″ that is forward in the direction of operation, while the rolls  36  are almost not loaded at all by the cylindrical bale. Thereby, the maximum measured value gives information about the weight of the cylindrical bale. On the basis of the measured values, particularly the height and/or the position of the maximum, the evaluation arrangement  64  determines the weight of the cylindrical bale. 
   The measured values of both sides shown in  FIG. 4  differ only slightly, which may be caused by the fact that the large round baler  10  is inclined to the left or to the right in the direction of operation, so that the cylindrical bale is in contact with a side wall  26  even though this has been moved outward. An inclination in the direction of operation does not falsify the measured value of the weighing arrangement, since the rolls  20 ′″ can roll along the underside of the cylindrical bale and are located underneath the cylindrical bale, regardless of the inclination of the baler  10  upon reaching the maximum of the curve of the measured values (see  FIG. 4 ). The evaluation arrangement  64  considers the mean value of the two measured values during the calculation of the weight and taking into account the sideways inclination of the baler  10 , detected by means of the inclination sensor  66 , in order to easily equalize the influences affecting the measured result. In addition, the weight of the loop of the baling elements  22  located between the pulleys  20 ′″ and the cylindrical bale can be subtracted from the measured value. Another solution is to calibrate the weighing arrangement of the baler  10  with cylindrical bales of various sizes, in order to obtain the most exact measured values. 
   Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.