Abstract:
A straw chopper for a combine harvester having a chopper housing mounted to a combine for rotation about a transverse axis. The housing is movable from a chopping position, in which the chopper receives straw from the separator of the combine and chops and spreads the straw over a wide area, to a rearwardly raised windrowing position, in which straw falls from the combine to the ground in front of the chopper housing. By rotating the housing rearward and upward, increased access into the rear of the combine is possible. An electric motor driven lift actuator is provided to raise the chopper housing to the windrowing position where a mechanical latch locks the housing to the combine structure.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a straw chopper for a combine and in particular to a straw chopper housing mounted to the combine for rotation about a transverse axis to move the straw chopper housing from a chopping position to a windrowing position. 
     2. Description of the Related Art 
     In a typical combine harvester, crop residue from the separator, also referred to as straw, is discharged from the hood structure at the rear of the combine. The straw is already somewhat reduced in size from the threshing and separating operations. If it is desired to reduce the size of the straw further, it is passed through a straw chopper. With current agricultural practices that eliminate or reduce tillage of the soil prior to planting, it is necessary to chop the straw into many small particles and then disperse the chopped straw over a wide area, generally equal to the width of the harvesting platform. As platforms have increased in width, it has been necessary to provide increasing width in the dispersion of straw at the rear of the combine. 
     Straw choppers have been used at the rear of the combine to chop the straw into small particles and to disperse the chopped straw over a wide area. The most common type of straw chopper consists of a transversely mounted flail rotor associated with a transverse array of fixed shear blades carried in a housing. The housing has an inlet opening and is supported beneath the combine hood to intercept the flow of straw from the separator. In some harvesting conditions, or to preserve longer straw for later collection, it is desired to return the straw to the ground in a narrow width windrow immediately beneath the combine hood without passing the straw through the chopper or widely dispersing the straw. 
     A straw chopper mounting for a combine is shown in patent 4,669,489 where a rear mounted straw chopper receives the straw from the straw walkers of the combine and discharges chopped straw rearwardly. The chopper is slidably supported on a pair of spaced apart, longitudinally oriented guide rails so that the chopper can be adjusted from a rearward chopping position to a forward windrowing position in which straw bypasses the chopper by dropping from the combine behind the chopper. Movement of the chopper on the guide rails is facilitated by attachment of a transverse shaft and sprocket assembly to the straw chopper housing. Teeth of the sprockets engage longitudinally spaced openings in the guide rails. Upon rotation of the shaft, the sprockets and guide rails cooperate in rack and pinion fashion to propel the chopper assembly along the rails while maintaining the chopper assembly in square alignment. The shaft is rotated by means of a wrench engaging flats on one end of the shaft. 
     Other straw choppers are mounted in a fixed position to the combine side sheets and use moving baffles or doors to direct the straw either into the chopper or directly to the ground for windrowing. With a fixed position chopper, the chopper restricts access to the rear of the combine for servicing or cleaning. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a straw chopper that is conveniently moved from a chopping position to a windrowing position to provide access to the rear of the combine for servicing operations. 
     It is a feature of the straw chopper of the present invention that the chopper housing is pivotally mounted to the combine side sheets for rotation about a transverse axis. The chopper housing is rotated upward and rearward from a chopping position to a windrowing position, allowing straw to drop to the ground forward of the chopper in the windrowing position. The chopper includes an inlet door that is mounted to the combine side sheets and is inclined downwardly and rearwardly from the rear end of the cleaning shoe. The inlet door directs both straw and chaff into the chopper. The inlet door is pivotally mounted to the combine such that when the chopper housing is in the windrowing position, the inlet door can be rotated downward from the inclined position to a vertical position to further improve access to the rear of the combine. In addition, the inlet door can be rotated upward to a generally horizontal, rearwardly extending position to provide convenient access to a tow hook mounted on the rear axle of the combine. 
     Another feature of the invention is a powered lift actuator to move the chopper housing between the chopping and windrowing positions. The powered lift actuator is preferably an electric motor driven screw actuator. A switch is provided on the side of the combine to enable the operator to raise or lower the chopper housing using electric power. The combine engine need not be operating to move the chopper housing. When the chopper housing is raised into the windrowing position, a latch automatically engages to attach the chopper housing to the combine structure, thereby relieving the load from the lift actuator. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a combine equipped with the chopper of the present invention. 
     FIG. 2 is an enlarged side view of the rear portion of the combine with the chopper of the present invention in a chopping position. 
     FIG. 3 is an enlarged side view of the rear portion of the combine with the chopper of the present invention in a windrowing position. 
     FIG. 4 is an enlarged side view of the latch for holding the housing in the windrowing position with the latch engaged. 
     FIG. 5 is an enlarged side view of the latch for holding the housing in the windrowing position with the latch released. 
     FIG. 6 is a perspective view of a bracket supporting the pin of the latch. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An agricultural combine  10  is shown in FIG.  1 . The combine  10  includes, among other things, a supporting structure formed by a pair of upright side sheets  12 , only one of which is shown in FIG. 1, and ground engaging wheels  14 . A harvesting platform  16  is used for harvesting the crop and directing it to a feederhouse  18 . The harvested crop is directed by the feederhouse  18  to a beater  20 . The beater directs the crop upward through an inlet transition section  22  to a rotary crop-processing unit  24 . A rock trap  25  is positioned between the feederhouse and the beater  20 . 
     The rotary crop-processing unit  24  threshes and separates the harvested crop material. It comprises a rotor  26  radially surrounded by a casing  28 . The rotor and the casing together define an inlet section  30 , and threshing section  32  and a separating section  34 . The rotor  26  comprises a hollow cylindrical drum having a plurality of crop processing elements that engage the crop and rotate it in the casing  28 . The bottom of the casing has a concave  36  under the threshing section  32  and a separating grate  38  under the separating section  34 . 
     Grain and chaff falling through the concave  36  and the separating grate  38  are directed to a cleaning system  40 . The cleaning system  40  removes the chaff and directs the clean grain to a clean grain elevator (not shown). The clean grain elevator deposits the clean grain in a grain tank  42 . The clean grain in the tank  42  can be unloaded into a grain cart or a truck by an unloading auger  44 . 
     Threshed and separated straw is discharged from the rotary crop-processing unit  24  through an outlet  46  to a discharge beater  48 . The discharge beater propels the straw downwardly and rearwardly through a discharge outlet  49  at or near the rear of the combine. The operation of the combine is controlled from the operator&#39;s cab  50 . 
     Mounted to the side sheets  12  at the lower rear end of the combine is a chopper  52 . The chopper  52  includes a chopper housing  54  that rotatably supports a rotor  56  for rotation about a transverse axis. The housing  54  generally surrounds the rotor. A belt drive, not shown, is used to rotate the rotor  56 . A plurality of blades or hammers  58  are attached to the rotor and pass between an array of stationary knives  60  mounted to the housing. The blades can be of any of a variety of types. A fan blade is preferred, having a flap portion at the trailing edge of the blade portion that is bent outward at a right angle to the blade portion to generate a fan action to facilitate the dispersal of the chopped straw. Such a blade is shown in U.S. Pat. No. 5,482,508. The knives  60  are carried by flanges  61  on each side of the housing  54 . The stationary knives can be inserted further into the chopper housing or retracted from the housing to vary the extent to which the straw is chopped. 
     A mounting plate  62  couples the housing  54  to a side sheet extension panel  64  at the pivot  66 . The side sheet extension panel  64  extends downward from the side sheet  12 . A mounting plate  62  and side sheet extension panel  64  is provided on each side of the combine. The housing  54  is allowed to rotate about the axis  68  of the pivot  66  extending transversely of the combine. 
     The front of the housing  54  is open, forming an inlet  70  to the housing. The housing further defines a rear outlet  72  for discharge of chopped straw therefrom. 
     The chopper housing  54  is moved from a chopping position as shown in FIG. 2 to a windrowing position shown in FIG.  3 . In the chopping position, the front end of the housing lower panel  80  engages the trailing edge of a chopper inlet door  82 . The inlet door  82  extends across the combine and is pivotally mounted to the side sheet extension panels  64  by pivots  84 . The chopper housing  54  includes a flange  83  with an open slot  85  at each lateral side. The slot  85  receives a pin  87  projecting laterally from each side of the inlet door  82  when the housing is in the chopping position. This ensures proper alignment of the housing with the inlet door. A retractable pin  86  holds the inlet door  82  in a position in which it is inclined downwardly and rearwardly from the pivot  84 . The pivot  84  is positioned generally adjacent the rear end of the chaffer whereby the inlet door directs both chaff and straw into the chopper housing. 
     The inlet door  82  is pivotally mounted to the combine so that the inlet door can be rotated downward from the inclined position to a vertical position as shown in FIG. 2 to further improve access to the rear of the combine. Rotation of the inlet door is accomplished by retracting the pins  86  from the side sheets of the combine to free the door to rotate about the pivot  84 . In addition, the inlet door can be rotated upward to a generally horizontal, rearwardly extending position (FIG. 2) and locked in place by inserting the pins  86  through the apertures  89  in the side sheet extension panels  64 . In this position, convenient access is provided to a tow hook  94  mounted on the rear axle of the combine (FIG.  1 ). 
     An inlet deflector  88 , in the form of a panel, extends between the two side sheet extension panels  64  and is pivotally mounted at pivot  90 . The inlet deflector  88  prevents any crop residue from entering the top portion of the chopper housing where the rotating chopper blades can propel the crop residue forward into the chaffer. Crop residue, such as corncobs, can damage the chaffer if they are propelled into the chaffer by the chopper. The inlet deflector  88  is connected to the chopper housing by links  92  on each side. As the chopper housing is moved upward and rearward to the windrowing position, the links  92  cause the inlet deflector  88  to rotate rearward and upward, providing greater access into the rear of the combine and allowing room for pulling the sieve and chaffer elements rearward from the cleaning shoe. 
     A powered lift actuator  96  extends between the chopper housing  54  and the combine structure to raise and lower the chopper housing. The actuator includes a screw actuator  98  driven by an electric motor  100  through a transmission  102 . A toggle switch  104  on the side of the combine, FIG. 1, is used to actuate the electric motor  100  to drive the actuator  96 . By using an electric driven actuator, the chopper housing can be moved between the chopping and windrowing positions without operation of the combine engine. A hydraulic cylinder can also be used to move the chopper housing, however this would require operation of the combine engine to provide the hydraulic fluid pressure. Other mechanical drive devices can be used as well, including linkages and gear drives. 
     A latch  110  is provided on each side of the chopper housing to attach the chopper housing to the combine structure when it is raised to the windrowing position. By latching the chopper housing in a raised position, the weight of the chopper housing need not be supported by the powered lift actuator once the chopper housing is in the windrowing position. The latch  110  includes an L-shaped pin  112  carried by a bracket  114  on each side of the chopper housing. A spring  116  biases the pin to the left as viewed in the figures. As the chopper housing is raised, the spherical end  118  of the pin  112  engages the angled end portion  120  of a bracket  122  mounted to the combine side sheet. The bracket end portion  120  causes the pin  112  to move against the biasing force of the spring  116 . When the chopper housing reaches the windrowing position, the pin  112  will snap through an aperture  124  in the bracket  122  and lock the chopper housing to the combine structure in the windrowing position. 
     Before the chopper housing can be lowered, the operator must first manually disengage the pin  112  on each side of the chopper. The pin  112  is withdrawn from the aperture  124  and retained in the withdrawn position (FIG. 5) by resting the leg  128  of the pin on the down turned flange portion  126  of the bracket  122 . As the chopper housing begins to move downward, the pin  112  will clear the down turned flange portion  126  of the bracket  122 . When this occurs, the spring  116  will bias the pin  112  forward. This causes the leg  128  of the pin  112  to contact the angled edge  130  of the bracket  114 . This causes the pin  112  to rotate about the axis of the pin main leg  131  so that the leg  128  points outward or downward. This prevents interference between the leg  128  and the down turned flange portion  126  of the bracket  122  when the chopper housing is next raised. 
     A tailboard deflector  132  is pivotally mounted to the housing  54  at the pivot  134 , FIG.  2 . The tailboard deflector has a plurality of fins  136  to deflect the exiting chopped straw laterally outward over a substantial width. The fins are adjustable in position to vary the width of the straw distribution. A pivot bar  138  is rotatably coupled to both of the side sheets. The pivot bar is also rotatably coupled to the tailboard deflector  132  in bushings  140 . As the chopper housing is rotated between the chopping and windrowing positions, the pivot bar  138  causes the tailboard deflector to rotate about the pivot  134  relative to the chopper housing. This enables the tailboard deflector to move between the use position shown in FIG.  2  and the folded position shown in FIG.  3 . 
     The chopper of the present invention, by pivoting the housing about a transverse axis between a chopping position and a rearwardly raised windrowing position, provides improved access to the rear of the combine for service and maintenance operations. In addition, the electric powered lift actuator enables the chopper housing to be raised and lowered without requiring that the combine engine be operating. The pivoting inlet door to the chopper housing further provides improved access to the rear of the combine as does the pivoting inlet deflector at the top of the chopper housing inlet. 
     The invention should not be limited to the above-described embodiment, but should be limited solely by the claims that follow.