Abstract:
A residue handling system for an agricultural combine including a residue chopper that provides enhanced air flow for evenly distributing crop materials onto a crop field. A hub and blade assembly accurately positions flail blades and resists fatigue stresses. Each flail blade includes an outer portion that is angled longitudinally away from a plane transverse to the axis of rotation. In a mated blade pair embodiment, the leading edges of the paired flail blades may be closer to each other than the trailing edges, or vice versa. Also, the leading edges of the flail blade pair may be the same distance away as the trailing edges of the pair, beneficially directing discharge sideways in a preferred common direction. The assembly includes a mounting support post that has a width substantially equal to the distance between two mated blades. The mated blades are installed directly against the sides of the mounting support, without spacer bushings, using only three connector elements.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to an agricultural combine. It relates particularly to a residue handling system for an agricultural combine. 
     BACKGROUND OF THE INVENTION 
     Agricultural combines are well-known machines for harvesting crop materials. They are available in various forms but all perform the basic functions of reaping crop materials from a field, separating grain from non-grain crop materials, and discarding the non-grain materials in the field. 
     A typical combine includes a crop harvesting or header assembly which reaps ripened crop plants from the crop field and a feeder assembly which feeds the crop materials to a threshing assembly. One type of combine incorporates a rotary threshing assembly. In such a combine, the crop materials are introduced to the front end of the rotary threshing assembly, which is oriented longitudinally, or axially, within the combine body. The crop materials are then threshed between a rotating rotor, which includes rasp bars along its exterior, and the inside of a rotor cylinder. Along the bottom of the rotor cylinder concaves are mounted that allow grain heads and other fine materials to pass through while retaining the crop stalks within the rotor cylinder. 
     The rotary threshing assembly includes mechanisms for feeding the crop materials rearwardly through the rotor assembly so that the crop stalks and other materials which do not pass through the concaves are discharged out the rear end of the assembly. The grain heads and other fine materials pass through the concaves onto a series of sieves that separate the grain from the unwanted fine materials. A cleaning fan directs air flow through the sieves to assist in the separation operation. After separation, the grain is conveyed to a grain bin through an auger system and the unwanted fine materials are discharged from the rear end of the sieves. 
     Modern farming practices require that the unwanted crop stalks be chopped up, mixed with fine materials, and evenly spread across the crop field. This is especially true with no-till farming, but is also important for more traditional farming techniques. 
     The demand for greater productivity has resulted in larger header assemblies, which harvest wider swaths in the crop field, and increased travelling speeds of the combine across the crop field. This has led to a need for more effective distribution systems for the non-grain crop materials. 
     A common type of non-grain or residue distribution system includes a residue chopper. The residue chopper is typically located in the rear of the combine body. Some types of residue choppers receive and distribute only crop stalks from the rotor assembly. Other types receive and distribute both crop stalks and fine materials from the sieves. 
     The residue chopper is oriented transversely of the combine and includes a plurality of flail blades which chop and mix the crop materials. The flail blades are pivotally connected to supports on a rotating hub. Normally, two flail blades are attached to each support, with one on each side of the support. In most prior art systems the two flail blades are spaced from the mounting support with spacer bushings. However, with such a construction, the mounting flange can become weak from continuously applied stresses and eventually break, causing unwanted downtime and repair costs. Additionally, use of these spacer bushings does not permit accurate positioning of the flail blades. 
     Air flow through the residue chopper greatly influences the effectiveness of the chopper in mixing the crop materials and distributing them from the rear of the combine. Vanes located at the exit of the residue chopper sweep in an outward direction to spread the crop materials across the crop field. Optimally, the crop materials will be discharged evenly in a swath which is the same width as the combine header assembly. However, because combine header assemblies can be as wide as thirty feet and more, the crop materials must exit the residue chopper at a high velocity in order to be directed across a wide swath. This necessitates a large volume of air flow through the residue chopper to achieve the desired exit velocity. 
     In residue choppers which receive both crop materials from the threshing assembly cylinder and fine materials from the sieves, it is a common practice to direct the cleaning fan air through the residue chopper. In this arrangement, the residue chopper housing becomes the primary path for the cleaning air, and the cleaning fan becomes the primary source of air flow through the residue chopper. The design and shape of the residue chopper&#39;s flail blades is important in ensuring adequate air flow through the chopper. Some known flail blades inhibit air flow through the residue chopper and actually create back pressure that partially prevents the cleaning fan air flow from entering the chopper. This not only adversely affects exit velocity of the crop materials but also reduces the effectiveness of the cleaning fan in separating the grain from the non-grain fine and light materials. 
     BRIEF SUMMARY OF THE INVENTION 
     It is a primary object of the invention to provide an improved residue chopper in a rotary combine. 
     It is also an object of the invention to provide an improved flail blade which assists the cleaning fan in moving air through the residue chopper. 
     It is another object to provide an improved flail blade which increases air flow through a residue chopper. 
     It is still another object to provide a flail blade which is configured intermediate its ends so that the front surface of the blade is inclined from the direction of blade travel in the chopper. 
     It is a further object of the invention to provide a mounting arrangement for the flail blades on a hub which includes a hollow mounting support having a width equal to the desired space between the inner ends of mated flail blades. 
     It is still a further object to provide a flail blade mounting arrangement which better resists fatigue stresses while providing more accurate flail blade positioning. 
     It is yet a further object to provide an improved hub and blade assembly in a residue chopper for a rotary combine. 
     It is yet another object to provide an improved hub and flail blade assembly including a pattern of flail blades which provides optimum residue distribution. 
     According to the invention, each flail blade is pivotally connected to a rotatable hub in a hub and blade assembly. An inner portion of the flail blade is flat and lies in a plane perpendicular to the axis of rotation of the hub. An outer portion of the blade is also flat, but is inclined from that plane. Thus, the front surface of the outer portion of the blade is inclined at an angle to the plane of rotation of the blade. As the blade rotates during operation of the chopper, this angled front surface increases the flow of air through the chopper housing by moving air ahead of it. 
     In a mated blade arrangement, two blades are attached to a single mounting support. In a first form of mated blade arrangement, the outer portions of the blades are angled in opposite directions so that the leading edges of the outer portions of two flail blades are closer to each other than the trailing edges. What amounts to a V-shaped pocket is formed behind the blades as they rotate. In a second form of mated blade arrangement, the trailing edges of the outer portions of mated blades are closer to each other than the trailing edges, creating a V-shaped pocket in front of the blades. In a third form of mated blade arrangement, the leading and trailing edges are equidistant from each other. A fixed knife attached to the housing passes between the leading edges of the mated blades when the hub rotates, producing a scissors cutting action to chop-up crop materials. 
     According to the invention, different forms of mated blade arrangements may be mounted on the same hub to create a pattern in the hub and blade assembly which produces a desired pattern of residue blown from the chopper. A hub and blade assembly may be effectively divided into three sections: a center section having the first and/or second form of blade arrangements thereon; a left section having the third form of blade arrangements thereon with the outer blade portions inclined so as to direct residue to the left as well as rearwardly; and, a right section having the third form of blade arrangements thereon with outer blade portions inclined so as to direct residue to the right as well as rearwardly. 
     The mounting support for each blade or mated pair of blades includes a rectangular cross-section post. The mounting support post has front, back, and side walls. The width of the post is substantially the same as the desired distance between the parallel inner portions of two mated flail blades, Therefore, the side surfaces of the inner portions on the flail blades directly contact the side walls of the mounting support post, without the need for spacer bushings. The flail blades can be pivotally mounted on the support post using only three mounting elements and a wrench. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
     The invention, including its construction and method of operation, is illustrated more or less diagrammatically in the drawings, in which: 
     FIG. 1 is a side elevational view of a portion of a rotary agricultural combine, with parts of the combine removed to display internal components; 
     FIG. 2 is a vertical sectional view through a straw chopper embodying features of the invention; 
     FIG. 3 is a perspective view of a portion of the hub and blade assembly in the straw chopper of FIG. 2; 
     FIG. 4 is a side elevational view of the hub and blade assembly the straw chopper of FIG. 2 with parts removed; 
     FIG. 5 is front elevational view of the hub and blade assembly seen in FIG. 4; 
     FIG. 6 is an exploded view of the blade mounting elements for the blades seen in FIGS. 4 and 5; 
     FIG. 7 is a front elevational view of a second form of hub and blade assembly for the straw chopper; 
     FIG. 8 is a front elevational view of a third form of hub and blade assembly for the straw chopper; and 
     FIG. 9 is a top plan view of a modified hub and blade assembly for the straw chopper of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, and particularly to FIG. 1, a portion of a rotary combine is shown generally at  10 . The combine portion  10  includes a feeder assembly  20  and a rotary threshing assembly  22 . The rotary threshing assembly  22  includes a rotor  26  and a rotor housing  28 . Crop materials travel rearwardly through the rotary threshing assembly  22  and are threshed by a series of threshing elements attached to the exterior of the rotor  26 . 
     Along the bottom side of the rotor housing  28  are perforated concaves  30  which allow grain heads and other fine materials to pass through, and out of, the rotary threshing assembly  22 . Larger material pieces such as crop stalks continue rearwardly through and are discharged out the rear end of the rotary threshing assembly  22 . 
     The grain heads and other fine materials are directed to a series of sieves  32 . A drive mechanism (not shown) effects a constant back and forth motion between the sieves  32 . As the crop materials pass through the sieves  32 , they further separate the grain from the unwanted chaff and fine and light materials. A cleaning fan  34  located forward of the sieves  32  blows air rearwardly through the sieves, thus helping to separate the grain from the fine and light materials. The cleaning fan  34  air also drives the unwanted fine and light materials out the rear end of the sieves  32 . 
     The distribution of unwanted crop materials onto the cleared field as the combine  10  travels across the field is effected by a residue chopper  40  embodying features of he invention. The chopper  40  chops the crop stalks into a finer residue material, mixes the chopped crop stalks with the chaff fine materials, and distributes the mixed residue evenly across the crop field. The residue chopper  40  is oriented transversely of the combine to the rear of the threshing assembly  22 . 
     Referring now to FIG. 2, the residue chopper  40  includes housing  42  mounted in the combine body  12  and elongated transversely of the body. The housing  42  encloses a rotatable hub and blade assembly  49 , including a hub  48  to which flail blades  50  are pivotally attached, preferably in mated pairs. The hub and blade assembly  49  is viewed from one end of FIG. 2, which shows it rotating in a counter-clockwise direction. 
     The housing  42  has front entrance  44  through which both crop stalks and chaff fine materials enter. It also has a rear exit  46  where chopped materials exit. To aid in spreading the exiting crop materials evenly across the field, vanes  47  are attached to the rear end of the combine body  12  near the rear exit  46 . The vanes  47  are angled outwardly so that the crop materials which exit the system  40  are redirected to cover a wide swath pattern. Optimally, the width of the swath pattern is equal to the width of the header assembly (not shown) attached to the feeder assembly  20  at the front of the combine. 
     To spread the crop materials over a swath of this width, the crop materials have to contact the vanes  47  at a high velocity. In order to achieve this high velocity, a large amount of air flow must be driven at a high speed through the housing  42 . The system  40  of the present invention accelerates the stream of air received from the cleaning fan  34  so as to produce an air flow speed of up to sixty miles per hour at the exit  46 . 
     Referring now to FIG. 3, in the hub assembly  49  a plurality of flail blades  50  are pivotally attached to a hub  48  in pairs  51 , arranged in a row spaced along the length of the hub  48 . In turn, four such rows are displaced 90° from each other around the hub  48 . Drive means (not shown), which are well known to those skilled in the art, rotate the assembly  49 . 
     Referring additionally to FIGS. 4 and 5, each flail blade  50  includes a flat inner mounting portion  54  lying in the plane of blade rotation, which is transverse to the axis of the hub  48  (“inner” and “outer” being relative to the connection of the flail blade with the mounting point with the mounting post). The outer portion  56  of the flail blade  50  is angled away from the plane of rotation of the blade. The blades  50  are pivotally connected to the hub  48  in a manner hereinafter discussed. 
     A preferred method of manufacturing the flail blade  50  is by bending a single piece of metal so that an intermediate portion  58  is bent in a smooth transition between the outer portion  56  and the inner portion  54 . In the illustrated blade,  50 , the outer portion  56  is flat, both longitudinally and transversely. Therefore, as the hub  48  rotates each radial line along its forward surface  60  travels along a different plane. 
     Although the invention envisions employing a variety of blade  50  angles, a preferred configuration has a flat outer portion  56  which is angled five degrees from the plane of blade rotation so that its projected frontal area is twelve millimeters wide. In an alternative configuration, the flat outer portion  56  is angled thirty-five degrees from the plane of blade rotation so that its projected frontal area is twenty-four millimeters wide. The specific angle of the outer portion  56  in a flail blade can be tailored to optimize the cutting action, i.e. fine or coarse, and the effect on exiting air flow velocity of the system  40 . 
     The flail blades  50  are preferably attached to the hub  48  in mated pairs  51 , as has been pointed out. In the arrangement seen in FIGS. 3-5, the leading edges  62  of the outer portions  56  on mated flail blades are relatively close to each other. The trailing edges  64  of the outer portions  56  on the mated blades, on the other hand, are relatively further from each other. A V-shape pocket is formed between, and behind, the outer portions  56  of the mated blades. 
     As the hub  48  rotates, the forward surfaces  60  of the outer portions  56  compress the air in front of the blades  50 , driving air forward. Also, a pressure drop is created in the pocket formed behind the rear surfaces  61  of the outer portions  56  of each pair of blades  50 , causing the rotating blades to draw air from the rear. 
     Referring to FIG. 2, attached to the base of the housing  42 , in fixed relationship, are a series of knives  43  (only one shown). The knives  43  extend upwardly, inside the housing  42 , between mated pairs of flail blades  50 . A scissor-like cutting action results as each flail blade  50  passes by a knife  43 . The cutting action chops the crop materials into a finer residue. 
     The knife blades  43  are all mounted in one, downwardly removable cassette (not shown). The number of knife blades  43 , and their placement, can then be easily changed, based on the angle and width of the flail blades  50 , in order to achieve a variety of fine or coarse cutting actions. 
     Preferably, the leading edge  62  of each flail blade  50  is sharpened, as at  63 , to enhance the scissor action. This is accomplished by relieving the leading edge  62  to a surface that it lies in the plane of blade  50  rotation, or is angled from this plane, so that this surface actually undercuts the forward surface  60 . 
     The blade  50  mounting support includes a mounting post  72  for each pair of blades  50  fixed to the hub  48 . Each post  72  comprises a rectangular cross-section tube extending radially away from the hub  48 . Each tube includes front and back walls  74  and  75 , and left and right side walls  76  and  77 . The outside width of the tube in each mounting post  72  is substantially the same as the desired distance between the mounting surfaces  52  of a mated pair of flail blades  50 . Thus, the mounting surfaces  52  of the flail blades  50  seat flush against the exterior surfaces of the side walls  76  and  77 . 
     Referring to FIG. 6, as well as FIG. 5, the mated pair of blades  50  are pivotally mounted on the support post  72  with a hollow pin  78 . The pin  78  extends through the inner portions  54  of the flail blades  50  and the mounting support side walls  76  and  77 . The pin  78  has a cap  79  at one end and an internally threaded bore  80  extending into the other end. A bolt  81  having a head  82  and a threaded shaft  83  is inserted through a washer  84  into the bore  80 . The threaded shaft  83  is received in the threaded bore  80 . The bolt  81  can easily be tightened with a wrench, acting on the head  82 . 
     In order to provide maximum contact area between the flail blade  50  and the mounting support  72 , and to allow pivoting clearance between the inner portion  54  of the flail blade and the hub  48 , the innermost edge of the flail blade is formed in a segmentally circular shape around the pivot axis of the bolt  78 . This is best seen in FIG.  4 . 
     The flail blades  50  are more accurately positioned in the present invention because spacer bushings, which are commonly used in prior art systems, are not required. Additionally, a greater area of surface contact and, thus, support is possible between the flail blade mounting surface and the mounting support side walls  76  and  77 . Because the flail blades are positioned more accurately, a more effective scissor action is made possible because each knife  43  may be positioned closer to the spaced flail blades  50  than is possible with prior art mounting systems. The tubular configuration of the mounting post  72  is also stronger than the simple tang mounts prevalent in the prior art. Therefore, the mounting post  72  can better resist fatigue stresses, stresses that cause tang mounts to break. 
     In the first form of blade assembly  49  which has been described, the leading edges  62  of mated blades  50  are relatively close to each other while the trailing edges  64  are relatively further apart. In a second form of blade assembly, seen in FIG. 7, just the opposite is true. In this form, the trailing edges  164  of mated blades  150  are relatively close to each other while the leading edges  162  are relatively further apart. 
     In a third form of hub and blade assembly  249  embodying features of the present invention, as seen in FIG. 8, the leading edges  262  and trailing edges  264  of the mated blades  250  are equidistant from each other. The outer portions  256  of each blade  250  in a mated pair are angled at anywhere between five degrees and thirty-five degrees from a plane transverse to the axis of rotation of the hub  248 . 
     Referring now to FIG. 9, another hub and blade assembly  349  embodying features of the invention is illustrated. The assembly  349  utilizes a combination of blade forms which produce a particularly advantageous result; serving both to enhance air flow through the chopper housing and the spreading of exiting crop materials across the field. 
     As seen in FIG. 9, the hub and blade assembly  349  includes a hub  348 . Six rows of mated pairs of blades  350  are mounted on the hub  348  (60° displaced from each other). Each row contains five evenly spaced pairs  351  of blades  350 . 
     Each row of blade pairs  351  also includes three different blade  350  arrangements,  350 A,  350 B and  350 C. In FIG. 9 in the uppermost blade row illustrated, each blade pair  351 A is constructed and arranged according to the first form of the invention. The blade pair  351  B is constructed and arranged according to one variation of the third form of the invention. Each blade pair  351 C is constructed and arranged according to another variation of the third form of the invention. 
     Insofar as variations of the third. form of blade pairs  351 B and  351 C are concerned, it will be seen that the variation resides in the direction of inclination of the outer portions  356  of blades  350  in question. The blades  350  in the pairs  351 B have both outer blade portions  356  inclined (in the same direction) so as to drive air axially outwardly of the hub  38 , as well as rearwardly. Similarly, the blades  350  in the pairs  351 C have outer blade portions  356  inclined (in the same direction) so as to drive air axially outwardly, as well as rearwardly. 
     Each row of blade pairs  351  has at least one, and sometimes as many as three, pairs  351 A (the pairs  351  are staggered in different rows). Each has, in addition, at least one pair  351  each of  350 B and  350 C blade configurations. The effect of this construction is to effect a powerful rearward and laterally outward flow of air from the system  40 . Spreading of crop material is further enhanced by this arrangement. 
     While a preferred embodiment of the invention has been described, it should be understood that the invention is not so limited, and modifications may be made without departing from the invention. The scope of the invention is defined by the appended claims, and all devices that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.