Patent Publication Number: US-2007101694-A1

Title: Netwrap Feed and Cut Mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is a Divisional of U.S. Ser. No. 10/719,460 filed Nov. 21, 2003, entitled NETWRAP FEED AND CUT MECHANISM, which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD  
      The principles disclosed relate to improvements to round balers used for harvest of agricultural crops. More particularly, the invention relates to improved reliability of the mechanism that feeds netwrap and controls tension of the netwrap to a formed cylindrical bale for wrapping the bale, as necessary to achieve a high level of reliability. The invention further relates to a feed mechanism that is configured to minimize potential negative influences related to crop material buildup and to minimize the potential for the netwrap material to be affected by the balers&#39;s pickup assembly. It further relates to the mechanism that severs the netwrap at the conclusion of the wrap cycle.  
     BACKGROUND  
      Many mechanisms have been developed for wrapping bales with netwrap, which is a sheet material typically in the form of light, very thin web material. Examples that utilize feed rollers are disclosed in R. M. Van Ginhoven et al U.S. Pat. No. 4,366,665; C. Clostermeyer et al U.S. Pat. No. 4,599,844; Krone et al U.S. Pat. No. 4,604,855; H. D. Antsey et al U.S. Pat. No. 4,697,402; J. L. Raes U.S. Pat. No. 4,729,213; DE 92 11 541; and J. H. Merritt U.S. Pat. No. 4,729,213 and commonly assigned Van Zee U.S. Pat. No. 5,129,208. The use of feed rollers to feed this light, unstable material has inherent limitations. A mechanism that does not utilize feed rollers is disclosed in Underhill U.S. Pat. No. 5,036,642. It is particularly adapted for feeding the netwrap into the front of a round baler. Another mechanism that does not utilize feed rollers, and is adapted for feeding netting into the rear portion of a baler is disclosed in Van den Wildenberg EP 0 820 691.  
      The supply roll of the netting material is known to be wider than the length of the cylindrical bale. Mechanisms have been developed to improve the feeding of this wide netwrap material. One early example is shown in Van den Wildenberg U.S. Pat. No. 4,917,008. Later mechanisms, to more reliably wrap the netwrap material around the edges of the bale, are disclosed in McClure et al. U.S. Pat. No. 6,550,218 and Myers et al. U.S. Pat. No. 6,006,504. The mechanism disclosed in Myers includes an element that interacts with the formed bale and cooperates with the lower idler roller that defines the net entry point, to provide space for entry of the outer edge of the netting material into the baler such that the outer edge does not contact the bale until some distance from the idler roller. The use of such an element, located near a roller at the bottom of a baler, was previously known, as disclosed in Meyer U.S. Pat. No. 4,910,949 as a wedge member that interacts with the formed bale to affect the sides of the bale.  
      In addition to feeding the material to the baler, the netwrap mechanism must sever the material, after the desired amount of netwarp has been dispensed. The Van den Wildenberg reference discloses a cutting mechanism comprising several moving parts that must work together to cut the netwrap.  
     SUMMARY  
      The present invention provides a reliable cost effective mechanism for feeding netwrap material from a supply roll, wider than the length of the cylindrical bale forming chamber, without the use of feed rollers, in combination with a simplified mechanism for cutting the netwrap. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic side view of an empty round baler;  
       FIG. 2  is a schematic side view of a round baler with a full-sized bale therein;  
       FIG. 3  is a partial schematic side view of the secondary inlet illustrating the configuration of the netwrap guides;  
       FIG. 3   a  is a partial isometric view of the net feed pan;  
       FIG. 3   b  is an enlarged view of area  3   b  as identified in  FIG. 3 ;  
       FIG. 3   c  is an isometric view showing the front net guide;  
       FIG. 3   d  is an enlarged side view like  FIG. 1  but showing the pickup, lower forming roller and one of the belt rollers;  
       FIG. 3   e  is a view like  FIG. 3   d,  but showing an alternate form of the wedge member;  
       FIG. 4  is a cross sectional view as would be viewed taken along viewing plane  4 - 4  shown in  FIG. 3   b;    
       FIG. 4   a  is a cross sectional view as would be viewed along viewing plane  4   a - 4   a  shown in  FIG. 3   b;    
       FIG. 4   b  is a cross sectional view as would be viewed along viewing plane  4   b - 4   b  shown in  FIG. 3   e;    
       FIG. 5  is a partial schematic section of the baler illustrating the netwrap mechanism in the cut/hold position;  
       FIG. 6  is a partial schematic section of the baler illustrating the netwrap mechanism in the power feed position;  
       FIG. 7  is a partial schematic section of the baler illustrating the netwrap mechanism in the tensioning position;  
       FIG. 8  is an isometric view showing the driver and its actuator; and  
       FIG. 9  is an isometric view showing the net knife. 
    
    
     DETAILED DESCRIPTION  
      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.  
       FIG. 1  illustrates a schematic side view of a round baler, illustrating the main functional components. A number of bale forming belts  20 , of a known flat configuration typically approximately ¼ to ½ inch in thickness and four to fourteen inches in width, are routed over several belt rollers that are in fixed positions including rollers  32 ,  34 ,  36 ,  38 ,  42 ,  44 ,  46  and  48 . These fixed belt rollers are supported by bearings, in any known method, that are mounted to a left side panel and a right side panel; the panels are not shown as many configurations of the panels are well known. The length of the rollers affects the spacing between the side panels and the length of the bale forming chamber and subsequent bale that that will be formed.  
      At least one of these rollers is rotated, typically by a chain drive. There are many known configurations for the drive system. The drive configuration illustrated in  FIG. 1  includes a drive system that powers the bale forming belts  20  including two drive rollers: roller  36 , driven by sprocket  50  and roller  32 , driven by sprocket  54 . Sprockets  50  and  54  are driven by chain  52  and chain  56  which are both coupled to sprocket  58 ; mounted to, and driven by, shaft  60 . Shaft  60  is connected to the output shaft of right-angle gearbox  62 . The input shaft of right-angle gearbox  62  is connected to driveline  64 , that transfers power from a towing vehicle, not shown.  
      The drive configuration further includes a drive to lower bale forming roller  72  including sprocket  66 , mounted to shaft of roller  32 , which is coupled to sprocket  70  by chain  68 . Sprocket  70  is mounted to and drives roller  72 .  
      The drive system further includes additional chain drives, not shown, to power the pickup assembly  80  and a starter roller  55 .  
      Pickup  80  functions to lift crop material  206  from the ground and into engagement with roller  72 . Roller  72  transfers the crop rearward, into engagement with the belts  20 . A rear, vertical section  22  of belts  20  is powered to move in an upward direction resulting from the powered rotation of rollers  36  and  32 . As the crop contacts this rear section  22  it will be lifted. Gravity and the downward movement of a front, vertical section  24  of belts  20  will tend to encourage the crop to fall back towards starter roller  55  which is turning in a clockwise direction. The material is thus directed back towards roller  72  which again feeds it rearward. The outside edges of the cylindrical bale will contact the side panels and wedge  204 , as the bale forms. In this manner the powered elements cooperate to roll the windrow of crop into a cylindrical bale.  
      As the bale begins to expand, the rearward section  22  and forward section  24  of belts  20  begin to envelop the bale. The belts  20  are able to envelop the circumference of and stay in contact with the bale as the belt tightener  82  and belt tightener rollers  84 ,  86  and  88  rotate counterclockwise as illustrated in  FIG. 2 , with a nearly formed bale  200 . Many mechanisms are known to be useful in controlling the movement and position of the belt tightener rollers.  
      Once a bale has reached its desired size, a wrapping material is applied to the outer circumference while it is still in the baler. After the bale is thus wrapped, the tailgate, which comprises a portion of the side panels and rollers  42 ,  44 , and  46 , will pivot around tailgate pivot  94 , allowing the finished bale to drop out of the baler.  
      The known wrapping materials include either rope-like twine made from either natural fibers or various types of plastic, or sheet-type netwrap typically made of a type of plastic material. In some of the claims “protective material” is a generic term used to describe material such as netwrap, but which could include many other things such as a sheet of plastic or fabric, for example. These other materials are fully equivalent to netwrap so it is to be understood that “netwrap” and “protective material” can be used interchangeably in the context of this invention. Twine is typically inserted into a crop inlet area  90  of the baler by a mechanism not shown, and applied in a spiral fashion by moving a twine arm, not shown, from one side panel across to the opposite side panel while the bale is rotating.  
      Sheet-type netwrap is known to be applied to the bale by inserting it into the baler at any available area, one known entry point being the rear of the baler, in a secondary inlet area  92 , located between roller  72  and roller  46 , as illustrated in  FIG. 2 , by netwrap mechanism  250  of the present invention. Netwrap is typically supplied in a roll  302  that is typically wider than the bale chamber. The netwrap material tends to neck-down between the supply roll and the inlet area  92 , yet remains wide enough to sufficiently cover the bale once the material is wrapped around the bale one time. However, since the netwrap is only secured to the bale by the interlacing of its strands with the discontinuous surface of the crop material, it is typically desirable to apply at minimum one and three-fourths to two wraps of the netwrap material. Several functions are critical to assure successful wrapping including:  
      1) feeding of the netwrap material in a manner to control of the width of the netwrap material, in order to minimize the amount that it necks-down, to maximize coverage;  
      2) feeding of the netwrap material in a manner to allow control of the length delivered to the bale including a mechanism that will reliably sever the netting material after the proper amount has been applied to the bale, and also hold the cut edge in a position as necessary to direct the leading edge for the next bale;  
      3) feeding of the netwrap material in a manner to allow control of a leading edge of the netting material from the supply roll to the bale, the associated mechanism having a self-cleaning ability in order to minimize the amount of stray crop material that can build-up in any areas where the netting may travel, to avoid the damage that this stray crop material can cause to the netting material;  
      4) application of adequate tension as the netting material is applied to the bale; and  
      5) control of the leading edge of the netwrap as it travels around bale for the initial time, to minimize the potential for entanglement with elements of the baler, in particular the pickup.  
      The process of wrapping a bale with netwrap mechanism of the present invention starts when the power feed system, which will be described later, directs a leading edge of netwrap from a held position near the supply roll  302 , to the feed pan  96  which is illustrated in  FIGS. 3 and 3   a.    
      Feed pan  96  includes a netwrap guide  98  located near to roller  46 , preferably one guide  98  for each baler belt  20 . Note:  FIG. 3   a  only shows one baler belt and only two netwrap guides, for clarity. There may be fewer guides  98  than there are baler belts. The feed pan  96  will include the proper number of components as required by the specific baler: a baler constructed to form a 4′ wide bale, for instance, will usually include a different number of belts than a baler constructed to form a 5′ wide bale, and the net feed pan for a 5′ wide baler will thus usually include a different number of netwrap guides than a net feed pan for a 4′ wide baler. Each netwrap guide  98  is narrower than the baler belts, and mounted below the belt  20 , supported by a frame  102  which is also narrower than the belt  20  and fixedly connected to cross-members including pivot shaft  100 , reinforcing rod  104  and reinforcing rod  106 . In this manner the netwrap guides  98  are mounted in a cantilevered fashion so that there are no cross-members  100 ,  104  or  106  in close proximity to roller  46 .  
      Referring again to  FIG. 3 , the pivot shaft  100  of the illustrated embodiment, the cross-member that is closest to roller  46 , is located a distance “D” in a range of 2 to 30 inches and is preferably 10 to 12 inches behind, and horizontally offset from, roller  46 . The horizontal offset is important because the movement of the belts  20 , combined with gravity, results in forcing the majority of the stray crop material towards roller  46 . Thus, any cross-member in close proximity, and particularly within close proximity along the horizontal axis, to roller  46  may restrict the stray material. Any restriction may result in eventual build-up to the point that it can interfere with the travel of the netwrap, either disrupting the movement of the leading edge, or damaging the netwrap material as it is applied to the bale. For example the support bar  96 , and the structure  90  above it, in  FIG. 8  of U.S. Patent Application Publication US 2003/0005663 provides a place for the crop to drop down from the baling chamber and accumulate on, creating a problem. From this illustration it will be appreciated that it is important to keep structural members out of that area to eliminate that problem.  
      The flexible net guides  98  are in a spaced relation to the lower roller  46  such that the flexible net guides  98  are supported by a cross-member  100  spaced a minimum horizontal distance from the lower roller  46  equal to the diameter of the lower roller  46 .  
      Also in  FIG. 3  is a dimension “d” which is the distance between the drum roller  72  and the belt roller  46 . The distance “d” between the drum roller  72  and belt roller  46  is less than the radius of the belt roller  46 , thereby forming a inlet for a leading edge of the protective material capable of reliably feeding the protective material to a place in the baling chamber where it can be wrapped around the bale. If this distance “d” is greater than the radius of the roller  46 , some of the crop being transferred by the drum roller  72  to the baling chamber will travel down to the ground between the drum roller  72  and the closest belt roller  46  and be lost instead of being part of the bale  200 .  
      In addition, the netwrap guides are constructed of spring steel, or any material capable of allowing frequent deflections, in order to move and thus to further minimize restriction to stray crop material that falls out of the baler, between belts  20 . Any material that does fall between the belts is thus able to fall to the ground.  
      Spring  108  attaches to reinforcing rod  106  to rotate the net feed pan  96  around the pivot shaft  100 , rotationally attached to the sides of the baler, until a top edge  110  contacts the baler belt  20  at roller  44 .  
      The upper portion of the net feed pan  96  extends beyond the top edge  110  creating a type of funnel  112  that feeds the netwrap material into the pinch point created where the top edge  110  contacts the baler belts  20 . As the leading edge of the netwrap material is fed by the power feed system to funnel  112 , it will be placed into contact with the baler belts  20  at the contact point  110 , subsequently following along with the moving baler belts along the length of the net feed pan  96 .  
      One aspect of the present invention affects the quality of coverage of the netwrap onto the bale. The quality of coverage is affected by the configuration of the inlet area  92  defined by relationship of roller  46 , roller  72 , wedge  204 , guides  98 , and the forming bale  200 .  
      Inlet area  92  is illustrated in  FIG. 3   b  as defined at the front by roller  72 , at the top by the bottom portion  202  of bale  200  and at the rear by roller  46 , which is indirectly in contact with bale  200  as belts  20  are positioned between the roller  46  and bale  200 . The sides  208  of the cylindrical bale  200  are in contact with the front side panels  16 , and with a bale wedge  204  on each end. Bale wedge  204 , as described in U.S. Pat. No. 4,910,949 which is incorporated herein by reference, functions to deflect the sides  208  of the bale  200  inward and upward, near the bottom perimeter  202 , as illustrated in  FIG. 4 . It has been found that this slight deflection is sufficient to provide space  210  required to allow the netwrap material  304  to engage the bale  200  at a place  212  across the bale, within the secondary inlet  92 , as it is guided around roller  46  by netwrap guides  98 .  
       FIG. 4   a  illustrates a partial cross sectional view along line  4   a - 4   a  of  FIG. 3   b  looking down towards the net guides  98 , showing the netting material  304  traveling through the net feed pan  96  from approximately point  306  to point  308 , identified in  FIG. 4   a,  at a width that is greater than the width between the tailgate side panels  18 . As the net material  304  follows the belts  20  around roller  46 , as guided by guides  98 , it is forced to be narrower to properly engage the bale  200 , in the same area as the previously identified space  210  where the bale  200  is slightly defelected away from the side panel  16  by wedge  204 .  
       FIG. 4   b  illustrates a partial cross sectional view along line  4   b - 4   b  of  FIG. 3   e  looking down towards the net guides  98 , showing the netting material  304  traveling through the net feed pan  96  from approximately point  306  to point  308 , identified in  FIG. 4   a,  at a width that is greater than the width between the tailgate side panels  18 . As the net material  304  follows the belts  20  around roller  46 , as guided by guides  98 , it is forced to be narrower to properly engage the bale  200 , in the same area as the previously identified space  210  where the bale  200  is slightly deflected away from the side panel  16  by wedge  204   a,  which is slightly different than the wedge  204  shown in  FIGS. 3   b  and  4   a.  Accordingly the void  210   a  formed is a slightly different shape and at a slightly different place than the void  210 .  
      When the leading edge reaches the inlet  92 , an initial length of netwrap material  304  will have been dispensed, sufficient to partially wrap a bale  200 . The process continues by guiding the leading edge of netwrap material  304  though the inlet  92  so that it contacts the formed bale, whereby the rotation of the bale  200  will trap the netwrap material  304  between the outer perimeter of the bale and the belts  20 . As the bale  200  continues to rotate, the netwrap material  304  will be aggressively pulled from the supply roll  302 . At that time the power feed system can be disengaged, and it is desirable to apply a significant drag so that the netwrap will be under tension as it is applied to the bale.  
      Referring to  FIGS. 1 and 2  as the leading edge of netwrap material  304  travels around the bale, with the belts  20 , it will eventually reach the bottom of the front vertical section  24  of belts  20 , in the vicinity of belt roller  32  and starter roller  55 . At this point the leading edge of netwrap material  304  can become unstable, and there is a possibility for it to come into contact with the pickup teeth  81  of pickup  80 . When this happens the netting can become partially entangled in the pickup  80 , which will damage the wrap material. To reduce the frequency of this entanglement, a guide  500  shown in  FIG. 2  is disposed below the start roller  55  to direct the leading edge back towards the drum roller  72 , and away from contact with the pickup  80 .  
       FIG. 3   c  is an isometric view from inside the baler looking towards the guide  500 , and illustrates a first embodiment of the guide, including a plurality of rigid bars  502  that extend in a generally horizontal direction to a position where they will contact the leading edge as it travels through this position.  FIG. 3   d  shows an alternative embodiment having a vertical element  504 , that may be a flexible sheet-type material, such as belt-type material, that extends to the pickup  80  to block the path of the leading edge of netwrap material  304 .  
      After the desired amount of netwrap material  304  has been dispensed, the netwrap is severed by the netwrap feed mechanism  250  ( FIG. 2 ) of the present invention, as will be described later, near the supply roll  302 . The netwrap material  304  that is stretched between the inlet point  92  and the severing mechanism, incluidng knife  400 , is pulled into the baler, finishing the wrap cycle.  
      The power feed, tension and cut functions, of the netwrap wrapping process, are provided by the netwrap mechanism  250 .  FIGS. 5-7  illustrate the netwrap mechanism  250  in 3 basic positions of a netwrap cycle:  FIG. 5  is the cut/hold position,  FIG. 6  is the powered feed position, and  FIG. 7  is the tensioning position. The operation of the netwrap mechanism  250  typically begins with the leading edge  300  of the netwrap material  304  held in position in preparation to begin feeding, as will be required to wrap the next finished bale, as illustrated in  FIG. 5 .  
      In this cut/hold configuration of  FIG. 5 , a length of netwrap material  304 , extending from a roll  302  of netwrap material  304  to the leading edge  300 , is routed around a net spreader roll  440  and over net pan  420  where it is held against a stationary knife  400  by cross member  470  of driver  460 . The netwrap mechanism  250  will be in this position during most of the baling process.  
      Once the bale  200  is formed to the desired size, the bale wrap cycle will be initiated when the driver  460  is pivoted clockwise around its pivot tube  462 . As driver  460  rotates from the position shown in  FIG. 5  to the position shown in  FIG. 6 , drive rollers  464  engage slot  424  of net pan  420 , causing net pan  420  to rotate around pivot tube  422  to the powered feed position shown in  FIG. 6 . This movement could be controlled by any of a number of mechanical drive elements. The preferred embodiment of the drive mechanism is illustrated in  FIG. 8  as a linear electrical actuator  441  that is anchored to the side panel  18  of the net wrap attachment  250 . Driver  460  is mounted on bushings, not shown, in areas  466  that mount to the side panels  18  of the netwrap mechanism  250 . It further includes side plates  468  that support cross members  470  and spreader roller  440 . Side plates  468  support drive rollers  464  that are further supported by arms  467 .  
      Driver  460  is rotated clockwise about pivot tube  462  as the actuator  441  on one end is retracted, the opposite end of the pivot tube  472  is used to activate linkage  474  that controls a force applied to a brake rotor  476 . Brake rotor  476  is connected to the roll of netwrap  302 . In this manner, as the driver is rotated fully clockwise, actuator is fully retracted, to the powered feed position shown in  FIG. 6 , the drive rollers  464  have engaged slots  424  of side plates  426  of net pan  420  pushing it into engagement with the baler belts  20 . Net spreader roller  440  has been moved to release any residual tension in the netting material  304  and the brake force is released on the net supply roll  302 . Thus, as the net pan  420  contacts the moving belts  20 , the leading edge  300  of the netting material  304  is fed to the funnel  112  of net pan  96  as the netting material is pulled from the net supply roll  302  under minimal tension.  
      Once the leading edge  300  is fed through the inlet area  92  as shown in  FIGS. 2 and 3   b,  and the netting material  304  is trapped between the baler belts  20  and the formed bale  200 , it will be aggressively pulled from the supply roll  302 , and the netwrap mechanism  250  will no longer need to power feed as shown in  FIG. 6  and can move to the  FIG. 7  tensioning position. Proper sequence of the netwrap mechanism  250  needs to insure that the leading edge  300  has been inserted into the inlet area  92 , during the power feed portion of the cycle. Many techniques could be used to control this sequencing. One technique is to simply use a timing technique. The distance between the stationary knife  400  and the inlet area  92  determines the amount of netting that needs to be fed off of the supply roll  302  during the power feed portion of the cycle, in order to insure that the leading edge  300  will be at the inlet area.  
      Since the baler belts  20  travel with a known range of speeds, as is necessary for proper operation of the baler, it is possible to determine the minimum time required for power feed, and the control system will hold the netwrap mechanism  250  in the power feed position for at least that amount of time. Another technique is to approximately monitor the amount of netting that is dispensed, for instance by moitoring the rotation of the brake rotor that is fixed to the netting supply roll. When the required amount of netting has been dispensd, to insure that the leading edge is trapped between that bale and belts, the netting supply roll will have rotated through a known angle of rotation.  
      The netwrap mechanism  250  will move to the tensioning position shown in  FIG. 7 , after the required duration in the power feed position of  FIG. 6 , as the actuator  441  is partially extended, moving driver  460  counter-clockwise, causing movement of drive roller  464  and related movement of plate  426  such that net pan  420  moves away from engagement with the belts  20 , to the position shown in  FIG. 7 . Net pan  420  is held in this position, because it is spring loaded or biased to rotate clockwise as viewed in  FIG. 7 .  
      Brake mechanism  474 , shown in  FIG. 8 , is simultaneously activated such that the brake  476  is applied to the net roll  302  when the mechanism is in the position shown in  FIG. 7 . The brake mechanism  474  is also activated by a linkage, not shown, connected to arm  480 , in a well known manner such that the brake force is affected by the size of the net supply roll; as the net material is pulled off the supply roll  302 , and it gets smaller, the amount of brake force is reduced such that the net tension is held approximately constant.  
      The mechanism  250  will be held in this  FIG. 7  tensioning position, with the brake applied, restricting rotation of net supply roll  302  to put the netting material  304  under tension, while an appropriate amount of netting material  304  is dispensed. After the appropriate duration, the actuator  441  will extend further, to reposition the mechanism  250  into the cut/hold position illustrated in  FIG. 5  wherein the cross member  470  of driver  460  deflects the path of the netting material  304  such that it travels through approximately a 90 degree angle over net knife  402 , which will cause the netting material  304  to be severed. At the same time, cross member  470  will trap the leading edge  300 , for the next wrap cycle, against a spring member  404  where it will be securely held.  
      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 “netwarp” is intended to include all sheet-type wrapping materials including tackified plastic materials and untackfied plastic materials. 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.