Abstract:
An improved bearing assembly for mounting a drive shaft and bearings, having an upper impeller drive shaft for the tailings conveyor of a combine harvester occupy the same space as the cleaning system rail and seal of a chaffer sieve, is disclosed. The assembly has a flush mounted bearing at one end of the shaft and a normal bearing and lock collar at the shaft&#39;s opposite end.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to combine harvesters but, more particularly, to improved sieve operation and grain cleaning. 
       BACKGROUND ART 
       [0002]    Cleaning systems, for combine harvesters, will cleanse threshed grain by blowing air through a set of planar sieves, utilizing gravitational forces to urge cleaned grain through the sieve openings. However, with higher capacity harvesting machines, the capacity for threshing the grain has increased beyond the throughput capacity of the attendant cleaning systems and the sieve operations. Accordingly, it is desirable to increase both the capacity and the efficiency of the cleaning systems, in combine harvesters, so that such systems contribute to an increase in the combine&#39;s overall rate of harvesting. 
         [0003]    In the past, this problem has been addressed in rotary cleaning systems by incorporating drive mechanisms compactly situated in a combine base unit where each of the individually driven components of the rotary cleaning device are rotatable about a common axis of rotation, i.e. a cleaning cylinder, an infeed mechanism, a fan, and an impeller are rotatable about said common axis of rotation and a composite drive shaft. The rotary system is discussed in, for example, U.S. Pat. No. 4,422,462 by Frans Decoene. 
         [0004]    However, for non-rotary tailings conveyors in combine harvesters, such as disclosed in U.S. Pat. No. 7,028,457 by Schmidt, which enable more efficient conveying of tailings by utilizing threshing plate units installable in a housing with vertically stacked drive shafts, each having a separate axis of rotation, there is a need for improved cleaning efficiencies with far more limited space restrictions. 
         [0005]    For example, a crop such as grain which is threshed into the clearances between the combine rotor and its housing, falls through perforations in the housing and is transported to a cleaning system which includes a chaffer sieve stacked atop a shoe sieve. The chaffer sieve and shoe sieve, as two members of the cleaning system, oscillate back and forth. Each sieve has a plurality of apertures for allowing the properly threshed grain to fall therethrough but not the chaff. A blower blows air up though the sieves and out the rear of the combine. The separated chaff will be blown outward along with the air, while the clean grain falls, theoretically, through the sieves onto an inclined plane. Clean grain then travels along the inclined plane and then through a grain elevator to a grain storage area. However, in order to save space, rail and seal attachments to the sieves are contoured in shape to accommodate, during oscillation, certain bearings and lock bars on drive shafts for the tailings conveyor or impeller that extends through the combine side sheets or walls. This contour permits an appreciable amount of clean crop such as grain, corn or beans to fall between the sieves and the side wall, failing therefore to fall onto the inclined plane, and thus never being carried to the grain elevator or storage bin. The combine side wall through which the drive shaft extends, serves as a common wall between the tailings conveyor unit and the combine itself. The wall structurally supports drive shafts, and impellers, from the tailings conveyor unit. Accordingly, there are bearings and lock collars required on the drive shaft which must be avoided by the chaffer sieve by way of a cut-out or a break in the rail and seal, or alternatively the rail and seal can be bent. This contour allows the chaffer sieve&#39;s oscillation to occur without rubbing against the bearing and lock collar, and without distorting the rotation of the drive shafts. 
         [0006]    A combine design that would enable more perfect seal of the sieves against the combine side wall and inhibit loss of crop, without weakening the impeller drive shafts or distorting shaft rotation would not only reduce crop loss, but save space, and reduce wear and tear on the bearing and lock collar. This would, in turn, satisfy a longfelt need in the industry, provide unexpected efficiencies, and advance the art of combine harvesters. 
       SUMMARY OF THE INVENTION  
       [0007]    What is disclosed is an improved tailings conveyor bearing assembly, including an improved drive shaft which overcomes one or more of the limitations and shortcomings set forth above. 
         [0008]    It is a feature of this invention that the need for lock bars or lock collars for bearing assemblies on the end of the tailings impeller drive shafts located closest to the sieves, is negated. 
         [0009]    It is another feature of this invention that the rails and seal will oscillate flush against the drive shafts and bearings without the need for bending or breaking the rail and seal, and will allow greater crop throughput during cleaning. 
         [0010]    It is also a feature of this invention that the rotation of the drive shaft and impeller is protected from distortion during contact with the oscillating chaffer sieve&#39;s rail and seal. 
         [0011]    These and other objects, features and advantages are accomplished according to the instant invention by providing a drive mechanism and assembly for the tailings conveyor cleaning function of a combine harvester. The invention comprises a shaft, having on one end, a self-locking flush mounted bearing, and at its opposite end, a non-locking bearing and a lock collar for mounting between a structural element such as a pulley or sheave and a wall. The first end portion of the drive shaft is configured to be received in a self-locking first bearing such that the shaft extends in a predetermined direction. The second end of the shaft is mounted through a second bearing in an opposite direction but having the same rotational axis as the first bearing, such that the drive shaft is receivable in a second bearing&#39;s receptacle but held in place by a spaced apart locking element, as, for example, a locking bar or lock collar. 
         [0012]    The invention enables mounting the combine tailing impeller drive shaft adjacent to the body of the combine efficiently, i.e. without loss of crop, or weakening of support, or distorting shaft rotation. The functional areas will all have improved output performances and the drive system will have improved reliability. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a simplified side view of a combine harvester embodying the relative positioning of the sieves, impellers and drive shafts which function more effectively as a consequence of my invention; 
           [0014]      FIG. 2  is a close-up cutaway top view of a prior art combine harvester&#39;s bearing assembly and a bent rail seal from the chaffer sieve, which bending is necessitated by the construction of the bearing assembly; 
           [0015]      FIG. 3  is a side view of a prior art combine harvester&#39;s bearing assembly of  FIG. 2  but also illustrating the drive shaft impeller, and top pulley or sheave; 
           [0016]      FIG. 4  is a side view of the combine harvester bearing assembly of my invention, further embodying an unbent rail and seal construction; 
           [0017]      FIG. 5  is a top view of the combine harvester bearing assembly and the unbent rail and seal of my invention as illustrated in  FIG. 4 ; 
           [0018]      FIG. 6  is a cutaway along line  6 - 6  of  FIG. 5 , illustrating a side view of the combine harvester bearing assembly of my invention, and also illustrating additional components of this invention; 
           [0019]      FIG. 7  is a further side view of the harvesting machine of my invention as illustrated in  FIG. 1 , depicting an embodiment of a tailings conveyor within the machine, with a cover or wall for the conveyor removed to show internal aspects such as the impeller design details; 
           [0020]      FIG. 8  is a perspective view of an embodiment of the conveyor of  FIG. 7  in association with a feed auger of the machine for feeding tailings to the conveyor; 
           [0021]      FIG. 9  is a simplified perspective view of the tailings conveyor of  FIG. 7 , showing embodiments of threshing plates of the invention; 
           [0022]      FIG. 10  is a simplified perspective view of the tailings conveyor taken along line  10 - 10  of  FIG. 9 ; and 
           [0023]      FIG. 11  is a frontal view of the tailings conveyor housing of  FIG. 7  with a cover or wall removed and illustrating tailings being conveyed through the conveyor in a turbulent manner as a result of contact with the threshing plates. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]    Referring to  FIG. 1 , an agricultural harvesting machine  10 , incorporating the principles of the instant invention, has a header  12 , and a feeder  16 . Crop material is collected by header  12  and taken into agricultural harvesting machine  10  through feeder  16  in a conventional manner. 
         [0025]    A threshing assembly  18  includes a rotor  20  and a perforated housing  22 . Rotor  20  is rotated within perforated housing  22 . Crop is received from feeder  16  and is passed through clearances between rotor  20  and perforated housing  22  to thresh the crop, e.g. grain. Grain which is threshed in the clearances between housing  22  and rotor  20  falls through the perforations in housing  22  and is transported to a cleaning system  24  including a chaffer sieve  26  and a shoe sieve  28 . Chaffer sieve  26  and shoe sieve  28  are members that oscillate back and forth against wall  100  which is a common wall between the tailings housing  40  and the cleaning system. Sieves  26  and  28  have a plurality of apertures for allowing the properly threshed grain to fall through. A blower  30  blows air through sieves  26  and  28  and out the rear of agricultural harvesting machine  10 . Chaff will be blown outward along with the air. The clean grain falls through sieves  26  and  28  onto an inclined plane  32 . Clean grain travels along plane  32  and then through a grain elevator  34 , to a grain storage area  36 . 
         [0026]    Grain and material other than grain (MOG), which is too heavy to become air borne and falls through chaffer sieve  26  but does not pass through shoe sieve  28  is commonly known as tailings. Tailings end up on a plane  38  and are rethreshed and conveyed in a tailings conveyor  40  and discharged from tailings conveyor  40  onto chaffer sieve  26 . 
         [0027]    As is best seen in  FIGS. 7 through 11 , tailings conveyor  40  includes a housing  42  including its wall  100  and an interior portion  43 ; a first opening  44  ( FIG. 9 ) communicating with interior portion  43 ; a first rotary impeller  46  and a second rotary impeller  48  located in interior portion  43 ; and a second opening  50  communicating with interior  43  and a conduit  52 . The first and second impellers  46  and  48  are each rotated in predetermined rotational directions A on shafts  58  and  51 , respectively, about substantially parallel rotational axes C and D extending longitudinally through the centers of shafts  58  and  51 , respectively. 
         [0028]    Housing  42  receives the tailings through first opening  44  of wall  100  by means of a conventionally constructed and operable auger  54 , as depicted in  FIG. 3 . Auger  54 , as shown in  FIGS. 8 ,  9  and  10 , rotates about rotational axis C on a shaft  56  coaxial with shaft  58  for moving the tailings toward tailings conveyor  40 , such that the tailings will be discharged by auger  54  through first opening  44  into interior portion  43  of housing  42  in a position to be propelled by rotating first impeller  46  through interior portion  43  to second impeller  48 . As an alternative, first opening  44  can be offset from the shaft  58 , such as depicted at  44   a  in  FIG. 9 , so that, for instance, tailings  60  are delivered into housing  42  at a lower location or more in the vicinity of the radial outer portion of first impeller  46 . 
         [0029]    First impeller  46 , and second impeller  48 , each include a plurality of blades  47  extending generally radially outwardly relative to the rotational axis of the respective impeller. Each of the blades  47  is preferably curved or arcuate so as to have a concave surface  47   a  facing oppositely of the rotational direction A, and a convex surface  47   b  facing forwardly in or toward the rotational direction A, such that each blade  47  is swept back relative to the rotational direction A, as best shown in  FIG. 11 . 
         [0030]    The impellers  46 ,  48  and the second opening  50  are preferably radially in-line or aligned, such that tailings  60  which enter housing  42  at opening  44 , or  44   a , are propelled in rotational direction A by first impeller  46  along a radially inwardly facing threshing surface  64   a  of a first threshing plate  64 , and into the path of rotation of radially adjacent second impeller  48 , as denoted by large arrow B. Second impeller  48  will then propel tailings  60  in direction A along a radially inwardly facing threshing surface  68   a  of a second threshing plate  68 , and through second opening  50  into conduit  52 . Tailings  60  exit through a discharge outlet  62 , so as to be spread over a predetermined region of chaffer sieve  26 , or another location if desired. In interior portion  43  of housing  42 , a radially inwardly facing common housing wall  66  guides and enhances the radial direction of travel of tailings  60  from first impeller  46  to second impeller  48 . 
         [0031]    The preferred rotational direction A for both of impellers  46  and  48  is clockwise. The curved or arcuate or swept back shape of the blades  47  on impellers  46  and  48  has been found to cause a more aggressive threshing of tailings  60  and forces the tailings  60  to the radially outer portion of the blades  47  faster, which has been found to increase conveying capacity. Threshing plate surfaces  64   a  and  68   a  may each have a rough surface texture or smooth, and/or can include elements such as raised protuberances and the like, for imparting a desired turbulence to the tailings flow, for performing a desired threshing function, as discussed in more detail below. 
         [0032]    Impellers  46  and  48  each include a mounting portion  82  which is preferably a hub, mountable to a rotatable member, such as shaft  58  of conveyor  40  in the instance of impeller  46 , for rotation with the rotatable member in a predetermined rotational direction, such as direction A, about a rotational axis, such as axis C, as best shown in  FIG. 11 . Each impeller  46  and  48  includes a plurality of blades  47 , preferably four in number, which extend generally radially outwardly from mounting portion  82  at equally spaced locations around the rotational axis. As noted before, each blade  47  includes a surface  47   a  facing in a direction opposite the rotational direction, and a surface  47   b  facing in the rotational direction. 
         [0033]    Referring back now to prior art  FIGS. 2 and 3 , the prior art cleaning systems required a conventional bearing  102  and locking collar  110  on the end of shaft  51  on the opposite side of wall  100  from the impeller  48 . This construction necessitated bending of wiper seal  101   a  which was connected to chaffer sieve  26 , which bending weakens the integrity of the seal and allows grain unseparated from the chaff to fall through the resulting opening between seal  101   a  and wall  100 . 
         [0034]    Referring to  FIGS. 4 ,  5  and  6 , the bearing assembly  102  of the present invention contains a polygonal or, preferably hexagonal interior profile within the bearing surface  109  which receives a congruently profiled stub shaft end  51   a  of shaft  51 , which stub shaft end  51   a  is therefore configured in a polygonal fashion for secure engagement with the inner surface  109  of bearing  102 . The walls  104  of bearing  102  define the inner race for the bearing. Walls  103  of bearing  102  define the inner race of bearing  102 . Shoulder  51   b  of shaft  51  rests firmly against bearing  102  and walls  104 . Connectors, such as carriage bolts  107  and nut  108 , can secure, for example, a mounting flange  106  for mounting bearing  102  to the wall  100 , or side sheet or alternatively  100  can be a cover. The bearing assembly of the present invention enables a stronger wiper seal construction  101  as depicted in  FIG. 5  which has greater integrity and can be flush mounted against wall  100 , thus preventing loss of grain or other crop and providing for a more efficient cleaning system. 
         [0035]    Conventional bearing  121  is mounted around shaft  51  and locking collar  120  is spaced apart relationship between wall  200  and sheave or pulley  201 . 
         [0036]    It will be understood that changes in the details, materials, steps, and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.