Abstract:
A method of grasping a bale of crop material and placing the bale in a bale wagon, the method comprising the steps of sensing, grasping and evaluating. The sensing step includes sensing a presence of a bale between grasping arms of a bale grasping mechanism. The grasping step includes grasping the bale with the grasping arms. The evaluating step includes evaluating a size of the bale that has been grasped.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to self-propelled agricultural bale wagons and, more particularly to bale wagons of the type adapted to pick up crop material bales in the field and automatically form stacks of these bales utilizing a variety of stacking patterns to form a stable, interlocked stack of bales. 
         [0003]    2. Description of the Related Art 
         [0004]    A bale wagon by G. E. Grey is described in U.S. Pat. No. 2,848,127, and is principally adapted for stacking bales and is basically comprised of three tandomly arranged cooperating tables. In operation, the basic Grey wagon functions to pick up bales, form them into a composite stack, and subsequently discharge the entire stack in a storage area. 
         [0005]    Present day practices in crop harvesting involve the formation of bales of crop material such as hay or other crops into stacks for storage by using an automatic bale wagon. One type of bale wagon that has achieved wide spread commercial acceptance is the automatic bale wagon which uses three tables as illustrated and described in U.S. Pat. No.  4 , 203 , 695  issued to Edward J. Wynn et al. 
         [0006]    Such bale wagons include a first table which receives bales from a bale loader or pick up device mounted on the bale wagon. The first table accumulates a predetermined number of bales with the bales being arranged in a row in a pattern determined by a computer on board the bale wagon. A second table receives the rows of bales from the first table and accumulates several such rows. This group of rows is commonly referred to as a “tier”. A third table or load bed then receives the tiers from the second table and accumulates these tiers to form a “stack” on the load bed. 
         [0007]    Once the stack has been accumulated on the load bed, it may be unloaded by pivoting the load bed 90 degrees and depositing the stack on the ground or other surface so that the first tier of bales which was accumulated on the second table is now the lowermost tier of the stack on the ground surface. In order to enhance the stability of the stack, it is desirable to vary the arrangement of the tiers within the stack, and the on-board computer is used to control tier pattern selection and formation on the wagon and the formation of bales into a predetermined sequence of tier patterns to form a block for stacking. 
         [0008]    It would be very beneficial to have a pattern selection process that does not add another complex control, but reduces the time, effort, and frustration required to choose a desired pattern. 
         [0009]    Current bale collecting system on self-propelled bale wagons require that the operator input the bale size being collected into the controller in order for the control system to determine the stack pattern to be used. This is fine provided the operator does not inadvertently select the incorrect bale size. If he does select the incorrect size, for example, selecting three foot bales when he is actually collecting four foot bales, the prior art systems cannot sense that the incorrect stack pattern is being used and will load three four foot bales when only two should be loaded. This can result in damage to the clamp mechanism when the third bale strikes the second bale on the second table, or a bale can become caught between the front of the second table and the clamp mechanism or cab. While neither of these scenarios present a danger to the operator, the time required to remove a very large and heavy bale from the bale wagon takes additional time and probably requires that the bale be cut, which is a total loss. Further, current systems cannot detect when a bale has broken during the clamping or lifting motions. In these cases, the operator must manually intervene to reset the system to inform the controller that a bale was not deposited on the second table. Likewise, if a 3×4 bale is sitting in its side in the field, current control systems will deposit the bale on its side on the second table, which will result in an uneven, unstable stack. 
         [0010]    What is needed in the art is a bale wagon system that eliminates the mistakes of the prior art stacking systems and stacks bales in an efficient cost saving manner. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention provides an inventive control system and method for a loading clamp of a large square bale wagon. 
         [0012]    The invention in one form is directed to a method of grasping a bale of crop material and placing the bale in a bale wagon, the method comprising the steps of sensing, grasping and evaluating. The sensing step includes sensing a presence of a bale between grasping arms of a bale grasping mechanism. The grasping step includes grasping the bale with the grasping arms. The evaluating step includes evaluating a size of the bale that has been grasped. The invention in another form is directed to an agricultural bale wagon including a chassis, an articulating mechanism coupled to the chassis, a bale grasping mechanism having a set of grasping arms, and a controller. The grasping mechanism is coupled to the articulating mechanism. The controller is configured to control the grasping arms and the articulating mechanism by carrying out the steps of sensing, grasping and evaluating. The sensing step includes sensing a presence of a bale between grasping arms of a bale grasping mechanism. The grasping step includes grasping the bale with the grasping arms. The evaluating step includes evaluating a size of the bale that has been grasped. 
         [0013]    An advantage of the present invention is that the bale size is evaluated as it is picked up. 
         [0014]    Another advantage is that the present invention is that the stack patterns are preserved since the size of the bale is known. 
     
    
     
       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 side perspective view of an agricultural bale wagon that uses an embodiment of a system for the detection of the sizes of the bales it picks up of the present invention; 
           [0017]      FIG. 2  is another view of the bale wagon of  FIG. 1  before it encounters a bale; 
           [0018]      FIG. 3  is a perspective view of the grasping mechanism of the present invention used with the bale wagons of  FIGS. 1 and 2 ; 
           [0019]      FIG. 4  is a closer perspective view of the grasping mechanism of  FIG. 3 ; 
           [0020]      FIG. 5  is another perspective view of the grasping mechanism of  FIGS. 3 and 4 ; 
           [0021]      FIG. 6  is a view of the grasping mechanism of  FIGS. 3-5  grasping a 3 foot bale; 
           [0022]      FIG. 7  is a view of the grasping mechanism of  FIGS. 3-6  grasping a 4 foot bale; 
           [0023]      FIG. 8  is a flowchart depicting the logic of an embodiment of the grasping system of the present invention; and 
           [0024]      FIG. 9  is a schematical block diagram of the grasping system that carries out the method of  FIG. 8 . 
       
    
    
       [0025]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Referring now to the drawings, and more particularly to  FIGS. 1-7 , there is shown a bale wagon  10  having a chassis  12 , wheels  14 , an articulating mechanism  16 , and a grasping mechanism  18 . Wheels  14  are coupled to chassis  12  and provide support to chassis  12 . Articulating mechanism  16  is coupled to chassis  12  and to grasping mechanism  18 , it provides the lifting, orientating and stacking functions of a bale that is grasped by grasping mechanism  18 , to position bales on bale wagon  10 . 
         [0027]    Grasping mechanism  18  includes grasping arms  20 , a clamp actuator  22 , a bumper  24 , springs  26 , a sliding member  28 , a bumper sensor  30 , a transport sensor  32 , a three foot sensor  34 , and a four foot sensor  36 . Grasping arms  20  are arranged to engage and hold a bale B in a squeezing, grasping or clamping fashion. Actuator  22  moves grasping arms  30  by causing sliding member  28  to move. Bumper  24  is positioned between arms  20  and is configured to move as it contacts a bale. Springs  26  bias bumper  24  outward and they are compressed when a bale contacts bumper  24 . The movement of bumper  24  is detected by the activation of bumper sensor  30 , thereby indicating the presence of a bale between arms  20 . Sensors  32 ,  34  and  36  are mounted to plate or channel  42 , with sliding member  28  sliding along triggering sensors  32 ,  34  and  36  dependent upon whether slide  28  is proximate to sensors  32 ,  34  and  36 , this triggering then providing feedback to detect the position of sliding member  28  and thereby whether a bale has been dropped, or if the bale is three feet wide or four feet wide. 
         [0028]    In looking at  FIGS. 3 and 4 , it can be seen that with no bale in  FIG. 3  bumper  24  is biased outward, then bumper  24  is pushed back with a portion of bumper  24  extending back as can be seen in  FIG. 4 . This triggers sensor  30  to indicate the presence of bale B being between arms  20 . Sequentially looking at  FIGS. 5-7  sensors  32 ,  34  and  36 , which are mounted to plate  42 , are shown as though looking through slide  28 , with the left portion of slide  28  shown in some of the Figs. The position of slide  28  relative to sensors  34  and  36  determine the width of bale B. For example in  FIG. 4 , bale B has contacted bumper  24  and slide  28  is to the right not covering any of sensors  32 ,  34  and  36 , with arms  20  fully open. In  FIG. 5  arms  20  are positioned in a transport mode and slide  28  completely encompasses sensors  32 ,  34 ,  36 . In  FIG. 6  sensors  34  and  36  are beneath slide  28  causing them to be triggered, and sensor  32  is not triggered indicating that a three foot bale is present. In  FIG. 7  sensor  36  is triggered by the proximity of slide  28  with sensors  32  and  34  being not triggered to then indicate that a four foot bale B being present. 
         [0029]    Now additionally referring to  FIGS. 8 and 9 , there is shown a method  100  to control grasping mechanism  18  and a structure of the system to carry out method  100 . Proposed here is an algorithm  100  to use feedback from the bale clamp position in order to determine the size of a bale and thus determine the tier stack pattern. Method  100  also provides automatic clamp initiation when bale B contacts bumper  24  thereby activating sensor  30 . 
         [0030]    The system executes method  100  as follows: 1. The control system  40  senses that a bale B has been engaged by the bumper  24  of the clamp  18  (see step  102 ). This is accomplished by the bumper  24  being pushed back, with respect to the clamp frame, and tripping a frame mounted sensor  30  (see step  104 ). If no bale is sensed method  100  proceeds to step  106 . 2. Upon sensing bale B, the control system  40  by way of controller  38  retracts clamp cylinder  22 , which squeezes bale B (this can either be accomplished using a translational/rotational system or a purely translational system). 3. When the pressure in the cylinder reaches a predetermined set point (see step  108 ), as a pressure adequate to clamp and hold bale B, the system  40  determines the width of bale B based on the position of the translational element  28  of the clamp. 4. If only the four foot (first) sensor  36  is tripped (see steps  110  and  112 ), the bale is four feet wide (step  118 ), then the system  40  determines that two bales are to be placed per tier (step  124 ). If the first sensor  32  and three foot sensor  34  (second sensor) are tripped (see steps  110  and  114 ), the system  40  determines that bale B is three feet wide (step  120 ) and that three bales are to be placed per tier (step  126 ). If the four foot sensor  36 , three foot sensor  34 , and transport sensor  32  are all tripped (see steps  110  and  116 ), the clamp  18  has retracted to the transport position and there is not a bale in clamp  18  (either a false reading on bumper sensor  30  or a dropped/broken bale has occurred). In this case, the clamp cylinder  22  is extended and the system  40  re-sets to clamp another bale, no bales are added to a tier. The logic controlling tier formation, i.e. bale count, will be used after the bale size has determined the stack pattern by the present invention. 
         [0031]    It is also contemplated that the method of sensing the size of the bale can be accomplished by different means. For example, the method described above can be substituted with a cylinder having internal extension sensing rather than discrete sensors. The clamp cylinder  22  retraction rate can also be used for sensing that a bale has been squeezed. That is, if the cylinder  22  has been retracted and has not tripped another sensor on the translational element  28  of the clamp for x-amount of time, it can be assumed that the bale is fully gripped and is ready to be lifted. The bumper sensor  30  can be replaced with an alternate form of sensing, such as a slave cylinder which is extended when the bumper  24  is pushed back. 
         [0032]    As depicted, there are four sensors  30 ,  32 ,  34 ,  36  located on the bale clamp  18 : one to initiate the clamp procedure, and three to determine bale size and/or presence. The logic works as follows for consistently sized bales: 1. The clamp squeezes the first bale B and determines the stack pattern based on the bale size: three bales per tier for three foot wide bales and two bales per tier for four foot wide bales. 2. Assuming the clamp  18  is always encountering the same sized bales, the loading and stacking system works the same way as current systems. The logic of the present invention works as follows for inconsistent bale sizes: 1. The clamp  18  squeezes the first bale to be loaded and determines its size. If it is a three foot bale, then system  40  will stack three per tier. If the bale is a four foot bale, then system  40  will stack two per tier. 2. The next bale is squeezed and the size is determined. If it is a three foot bale, it is placed on the rack in front of the first bale, assuming the first was three feet. If it is a four foot bale and the first was three feet, the arm  16  stops the lift cycle and alerts the operator that the bale does not match the load pattern being used. The operator is then prompted to manually disengage and drop the bale. The operator can then continue collecting bales provided they are of the appropriate size. This would function likewise if the first bale was a four foot bale and the second a three foot bale. 3. Assuming consistently sized bales are being collected thereafter, the operation of the second table and load rack of bale wagon  10  are the same as current systems and will not be discussed here in detail. 
         [0033]    The clamp function works as follows for broken or missed bales: 1. The first bale is collected as before, determining the stack pattern. 2. If at any point during loading the bump sensor  30  is tripped, initiating the clamp sequence, and all three sensors  36 ,  34 ,  32  are tripped at any point during the clamping or lifting cycle due to a broken or dropped bale, the control system  40  will alert the operator that a bale has been broken or dropped. Control system  40  will then automatically reset to pick up another bale in place of the broken/dropped bale. Current systems do not have this functionality and would continue collecting bales as though none had been lost and would create a stack missing a bale if the operator does not intervene. Advantageously the present invention also extends to the picking up of 3×4 bales and encountering a bale on its side, which if collected, would produce an uneven, unstable stack. System  40  will reject that bale, as it will sense that it is too narrow. 
         [0034]    Advantageously, with the present invention an operator can enter a field and not have to consider bale size when collecting bales, rather, the operator can simply begin picking up bales and the control system  40  will create the stack pattern based on the bale sizes that are sensed. 
         [0035]    This system will eliminate the very likely scenario where the operator has been collecting bales of one size, and goes to another field to collect bales of another size but forgets to set the controller to the new size, as is required with prior art systems. 
         [0036]    The present invention can work with any clamp mechanism that can accommodate differing bale widths without requiring the operator to manually adjust the bale clamp in order to lift bales of a differing size. 
         [0037]    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.