Patent Publication Number: US-2023148476-A1

Title: Residue chopper with counterblades and fins

Description:
BACKGROUND OF THE INVENTION 
     Agricultural machines, such as combine harvesters, typically process crop material, and deposit a portion of the material on the ground behind the machine. As the purpose of the harvester is to collect grain, the material that is deposited is primarily material other than grain (“MoG”), such as chaff and stalks. This is commonly called “residue.” It is generally desirable to minimize the size of the residue pieces, and to spread the residue evenly across the path of the machine. For this purpose, the machine may include a chopper to reduce the residue size, and a spreader to distribute the residue. 
     The chopper typically comprises a series of knives that rotate about a shaft and are partially enclosed by a shroud. The residue enters the shroud, and the knives strike and cut the residue. The effectiveness of the chopper (i.e., efficiency, processing flow rate, residue size reduction, etc.) can be influenced by external factors, such as the type of crop and crop conditions, and inherent factors, such as knife sharpness, number of knives, rotating speed, and dimensions of the parts. 
     Efforts to modify choppers to reduce the residue particle size typically focus on increasing the cutting action, or creating more opportunities for the knives to impact and cut the residue particles. The cutting action can be increased by sharpening the knives, altering the number of knives, and so on, or by adding counterknives that extend radially towards the shaft, and between adjacent pairs of the rotating knives, to provide additional cutting edges. Increasing the cutting opportunities can be achieved by adding a shredbar, which is an elongated plate or bar that extends in parallel with the chopper shaft rotation axis just outside the reach of the knives. The shredbar acts slows the residue movement and gives the moving knives more opportunities to cut the residue. Counterknives and shredbars may be fixed in place, or movable at the control of the operator or operating system to address varying crops and crop conditions. 
     While the foregoing devices provide some level of effectiveness, it has been determined that improved residue comminution can still be desirable. 
     This description of the background is provided to assist with an understanding of the following explanations of exemplary embodiments, and is not an admission that any or all of this background information is necessarily prior art. 
     SUMMARY OF THE INVENTION 
     In one exemplary aspect, there is provided a residue chopper comprising: a housing defining a partially enclosed cutting chamber; a shaft rotatably mounted within the cutting chamber and configured to rotate in an operating direction about a rotation axis extending along a longitudinal direction; a plurality of knives extending from the shaft at respective axial locations along the longitudinal direction, each of the plurality of knives extending from a respective proximal end at the shaft to a respective distal end at a radial distance from the shaft, the radial distance defining a cutting volume; a counterknife mounted to the counterknife support to move directly with the counterknife support; and a fin rigidly mounted to the counterknife support to move directly with the counterknife support, the fin being mounted behind the counterknife relative to the operating direction and having a blunt side facing against the operating direction. The counterknife support is movable between a first position in which the counterknife extends a minimum predetermined distance into the cutting chamber and the fin is not within the cutting chamber, a second position in which the counterknife extends an intermediate predetermined distance into the cutting chamber and within the cutting volume and the fin is not within the cutting chamber, and a third position in which the counterknife extends a maximum predetermined distance into the cutting chamber and into the cutting volume and the fin extends into the cutting chamber. 
     In another exemplary aspect, there is provided an agricultural combine comprising: a chassis configured for movement on a surface; a threshing and separating system attached to the chassis; and a residue chopper as described according to the foregoing aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of inventions will now be described, strictly by way of example, with reference to the accompanying drawings, in which: 
         FIG.  1    schematically illustrates a side view of an example of an agricultural combine having a residue chopper such as described herein. 
         FIG.  2    is a side view of an exemplary residue chopper. 
         FIG.  3    is a rear view of the residue chopper of  FIG.  2   . 
         FIGS.  4 A and  4 B  are detail side views of the residue chopper of  FIG.  2    shown in alternative operating positions. 
         FIG.  5    is an isometric view of a portion of the residue chopper of  FIG.  2   . 
         FIG.  6    is an isometric view of another exemplary residue chopper. 
         FIGS.  7 A and  7 B  are side views of another exemplary residue chopper. 
         FIG.  8    is an isometric view of a portion of the residue chopper of  FIGS.  7 A and  7 B . 
         FIG.  9    is an isometric view of another exemplary residue chopper. 
     
    
    
     In the figures, like reference numerals refer to the same or similar elements. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the present invention provide choppers which may be used in agricultural equipment (e.g., combines, windrowers, etc.), or in other environments. However, the invention is not limited to any particular application except as may be specifically recited in the claims. 
     Referring to  FIG.  1   , an example of an agricultural combine  100  is schematically illustrated. The combine  100  includes a chassis  102  that is supported for movement on the ground by wheels  104  (e.g., pneumatic tires or tracked wheels). A header assembly  106  is attached to the combine  100  and configured to receive crop material and convey such material to a threshing and separating system  108  located in or on the chassis  102 . The threshing and separating system  108  separates grain from the remaining crop material (also known as “material other than grain,” “MoG,” or “residue”) and an auger  110  or the like conveys the grain to a grain hopper  112 . The threshing and separating system may comprise an axial flow thresher, twin axial flow thresher, crossflow thresher, and so on. An unloader boom  114  may be provided to remove the separated grain as the combine  100  operates. 
     The residue exits the threshing and separating system  108  and falls into, or is otherwise conveyed to, a crop residue chopper  116 , such as those described herein. The residue chopper  116  comminutes the residue, and the residue is then delivered to a spreader  118 . The spreader comprises rotating disks or the like, which distribute the comminuted residue across the path of the combine  100 . 
     The features described in relation to  FIG.  1    are generally conventional, except for the residue chopper  116 , and no further explanations of their structures or operations are necessary. 
     Referring now to  FIGS.  2  and  3   , an example of a chopper  116  is illustrated and described in more detail. The chopper  116  includes a housing  120  having a housing inlet  122  and a housing outlet  124 , and defines a partially enclosed cutting chamber  126 . The housing  120  may be formed of sheet metal or the like, and may be assembled into a structure that installs within the combine  100 , preferably such that the chopper  116  is a replaceable unit. A shaft  128  is rotatably mounted within the cutting chamber  126 , and configured to rotate in an operating direction  130  about a rotation axis  132 . Any suitable drive mechanism may be provided to rotate the shaft  128 . For example, the shaft  128  may be driven by a hydraulic motor, an electric motor, or via a power takeoff from an internal combustion engine. 
     Knives  134  extend from the shaft  128  at respective axial locations along the rotation axis  132 . Each knife  134  extends generally radially from a respective proximal end  134   a  to a respective distal end  134   b . The proximal end  134   a  is fixed to the shaft  128 , and the distal end  134   b  is located at a radial distance R from the shaft. The radial distance R defines a cutting volume  136 . The cutting volume  136  extends in the longitudinal direction L (i.e., parallel to the rotation axis  132 ) as a cylindrical shape along the axial length of the shaft  128 , or at least the portion of the shaft  128  spanning the knives  134 . It will be appreciated that the knives  134  do not literally occupy the entire cutting volume  136 , but instead form a general region including the space in the longitudinal direction L between adjacent knives  134 . 
     The knives  134  are configured to cut crop residue. For example, the leading edge  134   c  of each knife  134  (i.e., the edge facing in the operating direction  130 ) may be sharpened, or include serrations, such as shown. The trailing edges  134   d  also may be sharpened or include serrations, as also shown, which allows the knives  134  to be turned around during service to extend their service life prior to replacement or sharpening. 
     Referring more specifically to  FIG.  3   , each knife  134  may be configured as two separate identical or similar blades  134 ′,  134 ″ that are fixed together by a pin  138  or bolt. The pin  138  may be connected to a post  140  that joins the two blades  134 ′,  134 ″ to the shaft  128 . The pin  138  may allow the blades  134 ′,  134 ″ to freely pivot (or be rotationally adjusted) relative to the post  140  about an axis that is parallel the rotation axis  132 , but this is not required. 
     The knives  134  may be arranged in knife pairs, such as the pairs designated as A, B and C in  FIGS.  2  and  3   . Each knife pair A, B, C has two knives  134  (and each knife  134  comprises two blades  134 ′,  134 ″) that extend from the shaft in opposite directions (i.e., the knives  143  are oriented at 180° relative to each other about the rotation axis  132 ). The knives  134  of each pair A, B, C are also joined to the shaft  128  at a common location along the rotation axis  132 . Each knife pair A, B, C is indexed about the rotation axis  132  relative to the adjacent knife pair A, B, C. For example, knife pair B is rotated relative to knife pair A by an angle of 20° to 70°, and knife pair C is rotated relative to knife pair B by an angle of 20° to 70°. In the shown exemplary embodiment, the each knife pair A, B, C is indexed 60° relative to each adjacent knife pair A, B, C, resulting in even angular spacing. Thus, the knives  134  are staggered relative to the rotation axis  132 . 
     The spacing along the longitudinal direction L between each knife pair A, B, C, may be equal, but this is not required. It will also be appreciated that other embodiments may have a single knife  134  at each location in the longitudinal direction L, or more than two knives  134  at each location. For example, one or more of the knife pairs may be replaced by sets of three knives  134  that are oriented at 120° relative to each other about rotation axis  132 , or sets of four knives  134  that are oriented at 90° relative to each other about the rotation axis  132 . The knives in any particular pair or group also may be oriented at uneven angles about the rotation axis  132 . For example, four knives  134  may be provided with the angular spacing between each knife  134  being 120°, 60°, 120° and 60°, in that order, around the circumference of the shaft  128 . Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure. 
     Referring back to  FIG.  2   , the residue chopper  116  also includes a counterknife support  142 , which is movably mounted relative to the housing  120 , and outside the cutting chamber  126 . The counterknife support  142  in this case is rotatably mounted to the housing  120  by a pivot  144 , but in other embodiments, the counterknife support  142  may be mounted to the housing  120  by a parallel linkage, a slider, and so on. 
     An actuator  146  is attached to the counterknife support  142 , and configured to move the counterknife  142  through a predetermined range of motion, as described below. The actuator  146  may be a hydraulic or pneumatic telescoping piston and cylinder assembly, a rotating or sliding cam, an electric motor, and so on. The actuator  146  may be manually operated, or operated by a control system. 
     A counterknife  148  and a fin  150  are mounted to the counterknife support  142 , preferably (but not necessarily) with the counterknife  148  between the fin  150  and the pivot  144 . The pivot  144  also preferably is located in front of the counterknife  148  and fin  150  relative to the operating direction  130 . The counterknife  148  may be rigidly attached to the counterknife support  142 , or mounted in a manner to allow some relative movement therebetween. For example, the counterknife  148  may be mounted to the counterknife support  142  by a pivot  152  and spring (not shown) that allows the counterknife  148  to rotate through a small range to help absorb large impact loads. The fin  150  preferably is rigidly mounted to the counterknife support  142 , such that is not adjustable relative to the counterknife support  142 . This provides a durable structure, and removes uncertainty of the system&#39;s performance during operation with various different compositions of grain material loading. This also avoids the option of making potentially-detrimental adjustments of the fin  150  position. 
     The fin  150  and counterknife  148  also may be connected to move directly with the counterknife support  142 . For example, as shown in  FIGS.  4 A and  4 B , there is a one-to-one relationship between motion of the counterknife support  142  and motion of each of the counterknife  148  and fin  150 . In this arrangement, there is no slack, such as would be provided by a lost-motion linkage (e.g., a slotted connection), between either the fin  150  or the counterknife  148  and the counterknife support  142 . This direct connection can include some capability for fully-regulated relative movement. For example, as explained above, the counterknife  148  might be mounted to the counterknife support  142  by a pivot  152  that allows limited pivotal movement about the pivot  152 , but the counterknife  148  will always move directly with the counterknife support  142  via their mutual connection at the pivot  152 . 
     The counterknife  148  may comprise a serrated, straight or curved sharpened edge facing against the operating direction  130 , to thereby present a sharp edge towards the incoming crop residue and enhance the overall cutting action of the chopper  116 . The counterknife  148  also may be reversible during service to present a fresh sharpened edge against the operating direction, or to present a different type of edge to the operating direction. For example, the shown counterknife  148  has a serrated edge on one side, and a straight edge on the opposite side, allowing interchangeability to obtain different performance characteristics. 
     The fin  150  is mounted to the counterknife support  142  behind the counterknife  148  relative to the operating direction  130 , such that the knives  134  pass the counterknife  148  before passing the fin  150 . The fin  150  preferably has a blunt side  150   a  facing against the operating direction  130 , as explained in more detail below. 
     The chopper  116  also may include other features. For example, a shredbar  154  may be mounted to the housing  120  at a location downstream of the counterknife  148  and fin  150 . In contrast to the pin  150 , which does not span multiple blades  134  along the longitudinal direction L, the shredbar  154  comprises a continuous bar or plate that extends into the cutting chamber  126  from the housing  120 , but does not intersect the cutting volume  136 . As is conventional, shredbar  154  extends continuously to span multiple knives  134  along the longitudinal direction L. In a preferred embodiment, the shredbar  154  extends the full distance of the cutting chamber  126  in the longitudinal direction L. The shredbar  154  acts as a dam to hold residue adjacent to the cutting volume  136 , to thereby enhance chopping (e.g., by providing a surface against which residue can be sheared by the knives  134 ). The shredbar  154  may be fixed or movable through a range of travel, and may be straight or include serrations or the like. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure. 
     Referring now to  FIGS.  2 ,  4 A and  4 B , the counterknife support  142  is movable between various operating positions. In a first position, shown in  FIG.  2   , the counterknife support  142  is moved to retract the counterknife  148  and fin  150  as far as possible (at least during normal operation) from the cutting chamber  126 . This is the fully-retracted operating position (in service, it may be possible to further retract the counterknife support  142  upon detaching an actuator  146  or other control linkages or mechanisms). In the first position, the counterknife  148  extends a minimum predetermined distance into the cutting chamber  126  and the fin  150  is not within the cutting chamber  126 . The minimum predetermined distance may be zero or less than zero (i.e., the counterknife  148  is not within the cutting chamber  126  at all), or a relatively small distance into the cutting chamber  126 . In this position, the counterknife  148  may be within the cutting volume  136  a minimum distance, or completely outside the cutting volume  136 . The first position may be a position selected such that the counterknife  148  does not materially contribute to the chopping operation. 
     In a second position, shown in  FIG.  4 A , the counterknife  148  extends an intermediate predetermined distance into the cutting chamber  126  and within the cutting volume  136 , and the fin  150  still is not within the cutting chamber  126 . The intermediate predetermined distance is greater than the minimum predetermined distance. In this position, the counterknife  148  contributes to comminuting the residue by, for example, acting as a cutting edge to sever residue or acting as a flow impediment that helps hold the residue to improve cutting by the knives  134 . It will be appreciated that the counterknife support  142  could be placed in a continuous range of different positions in which the counterknife  148  is within the cutting volume  136  and the fin  150  is not within the cutting chamber  126 , and all such positions would be considered a second position (as compared to the first position and third position as described herein). 
     In a third position, shown in  FIG.  4 B , the counterknife  148  extends a maximum predetermined distance into the cutting chamber  126  and into the cutting volume  136 , and the fin  150  also extends into the cutting chamber, and optionally into the cutting volume  136 . The maximum predetermined distance is greater than the intermediate predetermined distance, and this represents the fully-extended operating position of the counterknife support  142 . In this position, the counterknife  148  contributes to comminuting the residue as noted above, and the fin  150  further contributes to comminuting the residue by acting as an impediment to hold the residue as it is chopped by the knives  134 . 
     The relative dimensions of the parts can be selected based on expected operating conditions and empirical testing. For example, it is expected that a fin  150  having an effective length of about 5% to about 50% of the effective length of the counterknife  148  will be useful. (As used herein, the “effective length” is the respective distance by which each of the counterknife  148  and fin  150  protrude into the cutting chamber  126 , as measured radially relative to the rotation axis  132 , when the counterknife support  132  is in the third position.) It is also expected that a fin  150  having an effective length of about 15% to about 20% of the effective length of the counterknife  148  will provide a suitable configuration for many conditions. In this case, as the counterknives  148  approach about 80% to about 85% insertion, the fins  150  begin to enter the cutting chamber  126 , and when the counterknives reach the final (i.e., third) position, the fins  150  are fully projected into the cutting chamber  126 . Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure. 
     It is expected that the foregoing embodiment will provide advantages over devices having other arrangements of the parts. For example, locating the counterknife  148  between the fin  150  and the pivot  144  provides a large range of adjustment for the counterknife  148 , while having the fin  150  enter the cutting chamber  126  only near the end of the counterknife&#39;s  148  travel. Another advantage is that placing the counterknife  148  and fin  150  downstream of the pivot  144  results in the torque loading on the counterknife support  142 , which is generated by contact between the moving residue and the counterknife  148  and fin  150 , being generally applied in a single direction about the pivot  144 —namely, to drive the counterknife support  142  away from the cutting chamber  126 . This provides predictable operating torque characteristics, which facilitates design of a durable system. In contrast, locating the pivot  144  downstream of the counterknife  148  and fin  150  will lead to operating torques that push the assembly into the cutting chamber  126 , and could also lead to situations in which the operating torque about the pivot  144  changes in direction depending on the operating conditions, thus complicating the design of the system. 
       FIG.  5    illustrates a chopper  116 , such as the embodiment of  FIGS.  3 - 4 B , in the third position. In this case, the chopper includes a plurality of counterknives  148  and a plurality of fins  150 . The counterknives  148  are distributed along the longitudinal direction L, and a respective fin  150  is spaced behind each respective counterknife  148  relative to the operating direction  130 . In this case, each fin  150  is located at the same position along the longitudinal direction L as the respective counterknife  148  (i.e., the fin  150  and the counterknife  148  are in a common plane that is orthogonal to the rotation axis  132 ). The fins  150  may extend into the cutting volume  136  while in the third position, but this is not required. 
     The counterknives  148  and fins  150  may be operated individually, in groups, or all in unison. For example, each counterknife  148  and fin  150  may be attached to an individually movable counterknife support  142 , or all of the counterknives  148  and fins  150  may be mounted to a single counterknife support  142  that extends along the longitudinal direction. As another example, each counterknife  148  and fin  150  may be connected to an individual counterknife support  142 , but two or more counterknife supports  142  may be connected to move with each other. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure. 
     As will be apparent from the view of  FIGS.  2 ,  4 A,  4 B and  5   , the blunt side  150   a  of the fin  150  in this example comprises a simple flat surface that faces against the operating direction  130 . The blunt side  150   a  may, for example, be a flat rectangular or square surface that extends approximately radially to the rotation axis  132  when in the third position. As shown in  FIG.  4 A , the blunt side  150   a  extends from a proximal fin end  150   b  adjacent to the counterknife support  142 , to a distal fin end  150   c  that is spaced from the counterknife support  142 . One linear edge of the blunt side  150   a  lies along the distal fin end  150   c . In other examples, the blunt side  150   a  may converge to a point at the distal fin end  150   c , or may divide to multiple points at the distal fin end  150   c . The blunt side  150   a  also may have a rounded or non-linear shape around its perimeter. 
     In still other cases, the blunt side  150   a  may not be flat, or may only be partially flat. For example, the fin  150  may comprise a cylinder that extends from the proximal fin end  150   b  to the distal fin end  150   c . In this case, the blunt side  150   a  comprises a hemi-cylindrical surface facing in against the operating direction  130 . Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure. 
       FIG.  6    shows an alternative embodiment, in which each fin  150  is behind a respective counterknife  148  with respect to the operating direction  130 , but offset along the longitudinal direction L relative to the respective counterknife  148 . In this case, the fins  150  may be positioned at the same longitudinal position as a knife  134  located adjacent to the counterknife  148  (i.e., in a common plane orthogonal to the rotation axis  132  with a knife  134 ), such that the fins  150  should not be permitted to enter the cutting volume  136  in the third position, to ensure that the knives  134  do not contact the fins  150 . In other embodiments, the fins  150  may be offset along the longitudinal direction L relative to the associated counterknife  148 , but not in the same plane as any of the knives  134 , in which case the fin  150  can optionally enter the cutting volume  136  without being struck by the blades  134 . 
     In  FIGS.  5  and  6   , it will be seen that the in counterknives  148  and fins  150  may pass through one or more slots  156  through the housing  120 . The slots  156  preferably are shaped and dimensioned to limit intrusion of residue, and may include features such as movable covers or closable membranes to reduce residue loss. 
       FIGS.  7 A,  7 B and  8    illustrate an alternative embodiment, in which the fin  150  comprises a blunt side  150   a  in the form of a ramped surface facing against the operating direction. The ramped blunt side  150   a  extends from the proximal fin end  150   b  to the distal fin end  150   c , and the ramped surface at the distal fin end  150   c  is behind the ramped surface at the proximal fin end  150   b  relative to the operating direction  130 . Thus, the ramped blunt side  150   a  tends to guide residue away from the housing  120  and towards the cutting volume  136 . The ramped blunt side  150   a  may extend linearly from the proximal fin end  150   b  to the distal fin end  150   c , or it may comprise a concave surface facing against the operating direction  130  (such as shown), or a convex shape facing against the operating direction  130 . Other shapes are also possible. It is expected that the shown concave shape will be effective at redirecting residue and also slowing residue movement along the operating direction  130 , thus improving chopping performance. 
       FIG.  9    shows a variation of the embodiment of  FIGS.  7 A,  7 B and  8   , in which each fin  150  is behind a respective counterknife  148  with respect to the operating direction  130 , but offset along the longitudinal axis L relative to the respective counterknife  148  (similar to the embodiment of  FIG.  6   ). 
     Embodiments such as those described above are expected to provide improved chopper performance for a variety of crop and operating conditions. The movable counterknife allows basic adjustment, while the fin can be brought into operation when it is desired to add a crop flow impediment to achieve a “shredbar” effect allowing more cuts by the knives. When fully inserted, the fin can also act as a shear surface to hold the crop residue closely to the cutting volume to cause more aggressive contact with the knife, and a ramped fin surface can help redirect the crop material into the knife path. It is also expected that the use of discrete fins will generate less drag than a conventional straight or toothed shredbar, thus requiring less operating power and increasing efficiency. 
     The present disclosure describes a number of inventive features and/or combinations of features that may be used alone or in combination with each other or in combination with other technologies. The embodiments described herein are all exemplary, and are not intended to limit the scope of the claims. It will be appreciated that various aspects of the embodiments described herein may be provided as component parts or as subassemblies. It will also be appreciated that the inventions described herein can be modified and adapted in various ways, and all such modifications and adaptations are intended to be included in the scope of this disclosure and the appended claims.