Abstract:
A grain paddle for a clean grain elevator of a combine harvester. The paddle includes a substantially rigid body with a planar portion having ends disposed distal and proximal to an elevator chain of the combine harvester. Some paddle embodiments include an angled end adjacent the proximal end of the planar portion. Some paddle embodiments include an angled end adjacent to the distal end of the planar portion. Some paddle embodiments include sloped lateral edges.

Description:
BACKGROUND 
       [0001]    Referring to  FIG. 1 , when harvesting crops with agricultural harvester combine  10 , the crop being harvested is cut or collected as the combine traverses the field, by the head or header  12  mounted to the forward end of the combine  10 . The header  12  feeds the crop into the feeder house  14  which carries the crop to the thresher, indicated generally by reference numeral  16  within the interior of the combine  10 . The thresher  16  removes the grain from the plant material (e.g., the stalk, cob, pods or other plant material depending on the crop being harvested). The threshed grain then passes through sieves, indicated generally by reference numeral  18 , which separate the grain from the unwanted plant debris. The unwanted plant debris is passed toward the back of the combine where it is discharged. The sieved “clean” grain is directed toward and is collected at the bottom of the clean grain elevator  22 . The clean grain elevator  22  lifts the collected clean grain upward into a discharge area  24 . An auger  26  within the discharge area  24  carries the grain into a holding tank or hopper  28 . As the hopper  28  begins to fill, the grain is unloaded as needed by the unloading auger  30  into a waiting grain cart, wagon, truck or other transport (not shown). 
         [0002]    Referring to  FIGS. 1 and 2 , the clean grain elevator  22  is disposed within a housing  32  and is comprised of a chain  34  which passes around upper and lower sprockets  36 ,  38 . A plurality of equally spaced flights or paddles  40  are attached to the chain  34 . As the chain  34  is rotated by the sprockets  36 ,  38  the paddles  40  scoop the grain being collected at the bottom of the elevator  32  and lift it upward toward the top of the elevator housing  32 . As the paddles  40  pass over the upper sprocket  36 , the grain is thrown into the discharge area  24  as illustrated in  FIG. 2 . 
         [0003]    In many combines, a yield sensor  50  is positioned in the discharge area  24 . While there are many types of yield sensors, a common yield sensor  50  includes an impact plate  52 . The impact plate  52  is positioned so that when the grain is being thrown by the paddles  40  as the paddles  40  pass over the upper sprocket  36 , the grain “impacts” the impact plate  52 . The impact of the grain causes the impact plate  52  to displace which generates a signal. The signal generated due to the displacement of the plate  52  correlates to the amount of grain impacting the plate which correlates to yield. However, in operation of yield sensors for which a layer of grain imposes a centrifugal force on the yield sensor, empirical studies have shown that conventional paddles generate inconsistent signals at the yield sensor, particularly at low grain flows. Accordingly, there is a need for an improved paddle for clean grain elevator of a combine that will throw the grain in a manner so as to obtain a more accurate and consistent yield measurements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a side elevation view of a conventional combine. 
           [0005]      FIG. 2  is an enlarged view of the circled portion of  FIG. 1 , illustrating how prior art paddles tend to scatter or spray the grain as the grain is thrown toward the yield sensor. 
           [0006]      FIG. 3  is an illustration of the same view of the clean grain elevator as in  FIG. 2 , but showing how the improved paddles direct the grain in a more contiguous mass toward a mass flow sensor positioned proximate the upper sprocket of the clean grain elevator. 
           [0007]      FIGS. 4A-4F  are side elevation views of several embodiments of an improved paddle. 
           [0008]      FIG. 5  is a side elevation view of another embodiment of an improved paddle shown in relation to the upper sprocket and chain of the clean grain elevator. 
           [0009]      FIG. 6  is a top perspective view of another embodiment of an improved paddle. 
           [0010]      FIG. 7  is a cross-sectional view of the improved paddle of  FIG. 6  as viewed along lines  7 - 7  of  FIG. 6 . 
           [0011]      FIG. 8  is a cross-sectional view of the improved paddle of  FIG. 6  as viewed along lines  8 - 8  of  FIG. 6 . 
       
    
    
     DESCRIPTION 
       [0012]    Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  is a side elevation view of a conventional combine  10  with a partial cut-away view of the clean grain elevator  22  and showing a yield sensor  50  disposed at the top of the clean grain elevator  22 .  FIG. 2  is an enlarged view of the circled portion of  FIG. 1 . The clean grain elevator  22  is disposed within a housing  32  and is comprised of a chain  34  which passes around upper and lower sprockets  36 ,  38 . A plurality of equally spaced flights or paddles  40  are attached to the chain  34 . As the chain  34  is rotated by the sprockets  36 ,  38  the paddles  40  scoop the grain being collected at the bottom of the elevator  32  and lift it upward toward the top of the elevator housing  32 . As the paddles  40  pass over the upper sprocket  36 , the grain is thrown into the discharge area  24 . 
         [0013]    Conventional paddles  40  are generally rectangular in shape and are substantially planar. Some conventional paddles  40  have a slight cup or concave shape in the direction transverse to the chain  34 . Conventional paddles are also typically constructed of recycled tires so they are somewhat flexible and become irregularly shaped during use due to elastic deformation and after use due to plastic deformation. The flexibility and irregular shape of conventional paddles  40  results in inconsistent grain piles on the paddles as the grain is being lifted by the elevator  22 . Because impact-type yield sensors generate signals based on the amount of displacement of the impact plate due to impact of the grain, if the grain piles on the paddles are not consistent due to the flexibility or irregular shape of the paddles, the signals generated will likewise be inconsistent which translates into inaccuracies in yield measurements. Furthermore, when these flexible, irregularly shaped paddles pass over the upper sprocket, they tend to scatter the grain as it is thrown toward the yield sensor as illustrated in  FIG. 2  which further contributes to inconsistent and inaccurate signals generated by the yield sensor. 
         [0014]      FIG. 3  is an illustration of a partial cut-away view of the upper end of a clean grain elevator similar to  FIG. 2 , but in  FIG. 3 , the conventional paddles  40  are replaced with improved paddles  100 . The improved paddles  100  are configured with fore and aft sloped ends  102 ,  104  extending from a substantially planar middle portion  106 . The improved paddles  100  are constructed of substantially rigid, wear resistant material which will maintain its shape during use. Such material may include thermoplastic polyethylene such as high density polyethylene (HDPE), ultra high molecular weight (UHMW) polyethylene or another material with like properties. In other embodiments, the improved paddles  100  are constructed of stainless steel or another rigid metal. The paddles  100  mounted to the chain  34  are preferably substantially identical such that a substantially identical grain pile is carried up the elevator and thrown toward the sensor  200  by each paddle  100 . The overall length and width of the improved paddle  100  is substantially the same as the overall length and width of a conventional paddle  40  and may incorporate the same means of attachment to the elevator chain  34  as a conventional paddle  40 . Thus, no change needs to be made to the sprockets  36 ,  38 , to the chain  34  or to the elevator housing  32  to replace or retrofit the clean grain elevator  22  of an existing combine  10  to utilize the improved paddles  100 , nor is there a need for an original equipment manufacturer to change the design of the elevator  22  to achieve the benefits of the improved paddle  100  as described below. 
         [0015]    The combination of the sloped fore and aft ends  102 ,  104  and rigid construction of the improved paddles  100  ensures a larger and more consistent grain pile (even at low flows) on each paddle. When using a mass flow type yield sensor, a greater and more consistent grain pile on each paddle will produce a stronger and more consistent signal when the grain pile is directed over or passes the mass flow sensor. It should be appreciated that the improved paddles  100  also direct a more contiguous grain layer over the mass flow sensor rather than scattering the grain, further improving the accuracy of the yield sensor signal, even at low flows. Furthermore the rigidity and sloped ends of the improved paddles  100  reduces scattering of the grain when the paddles pass over the upper sprocket  36  as compared to flexible, irregularly shaped conventional paddles. 
         [0016]    By combining the benefits of the improved paddles  100  with a yield sensor  200  of the type disclosed in Applicant&#39;s co-pending International Patent Application No. PCT/US2012/050341 (the &#39;341 Application), the disclosure of which is incorporated herein in its by reference, further improvements in the accuracy of yield measurements can be achieved. 
         [0017]    As disclosed in the &#39;341 Application, and as shown in  FIG. 3 , the yield sensor  200  is positioned in the elevator housing  32  such that the mass flow sensor  202  of the yield sensor  200  is located proximate the longitudinal axis  204  of the elevator  22  which passes through the central axis of the upper sprocket  36 . The improved paddles  100  are particularly adapted to direct a greater portion and a more contiguous mass of grain upon leaving the paddle  100  toward the mass flow sensor  202 . Because a greater and more consistent mass of grain with a more contiguous mass is directed toward the sensor  200 , a greater portion of each grain pile contributes to the centrifugal force exerted on the mass flow sensor  202  as the grain contacts the sensor  202 , thereby generating stronger and more consistent signals which correlate to more accurate yield measurements. 
         [0018]    Various embodiments of the improved paddle  100  are illustrated in  FIGS. 4A-4F . As previously identified, each of the embodiments of the improved paddles  100  include a generally flat or planar middle portion  106 , and sloped fore and aft ends  102 ,  104 . A slope angle A 1  defining the sloped aft end  104  may be between about 5 to 20 degrees. A horizontal distance between the rear and forward ends of the aft end  104  may be between 0.5 and 3 inches. A slope angle A 2  defining the sloped fore end  102  may be between about 10 to 30 degrees. A horizontal distance between the rear and forward ends of the fore end  103  may be between 0.75 and 2 inches. A horizontal distance between the fore and aft ends of the paddle  100  may be between 3.5 and 5.5 inches. A slope angle A 3  defining a sloped rearward portion of the middle portion  106  (in the embodiment of  FIG. 4E  in which the middle portion  106  is not entirely flat) may be between about 5 and 10 degrees. A total horizontal width of the paddle  100  may be between 4 and 5 inches. A rearward distance D 1  between a central axis of a bolt mounting the paddle  100  to the chain  34  and a rearward end of the flat middle portion  106  may be between about 0 and 2 inches. A forward distance D 2  between a central axis of a bolt mounting the paddle  100  to the chain  34  and a forward end of the middle portion  106  may be between about 0 and 1 inches. A rearward distance D 3  between a rearward end of the sloped middle portion  106  and a forward end of the sloped middle portion  106  may be between about 0 and 0.5 inches. As previously identified, the sloped fore and aft ends  102 ,  104  enable each paddle to carry a greater and more consistent grain pile as the paddles scoop and lift the grain from the bottom of the elevator to the top of the elevator. Furthermore, the sloped aft end  104  (i.e., the end toward the rear of the combine as viewed in  FIG. 1 ), assist in directing a greater and more contiguous mass of grain toward the sensor  202 , as the grain leaves the paddle  100  as the paddle begins to pass around the upper sprocket  36 . 
         [0019]    Another embodiment of the improved paddle  100  is illustrated in  FIG. 5  attached to a chain  34  of an elevator  22  and carrying a grain pile  60 . In this embodiment, the paddle  100  includes sloped fore and aft ends,  550 ,  552  configured such that the center of gravity of the grain pile  60  is located toward the fore end  550  of the paddle  100  as the grain is carried up the elevator. 
         [0020]    The paddle  100  is attached to the chain  34  by a mounting arm  510  and a shim  520 . Bolts or other suitable connectors (not shown) secure the paddle  100  to the mounting arm and shim  520 . The shim  520  is configured such that angle of an upper surface of the shim and a vertical thickness of the shim affect the orientation of the paddle when mounted on the mounting portion  510 . While the paddle  100  is carried up the elevator before reaching the upper sprocket  36 , an angle A 1  between the sloped aft end  552  and a plane Ph is preferably between 2 and 6 degrees and an angle A 2  between the sloped fore end  550  and the plane Ph is preferably between 30 and 60 degrees such that the grain pile  60  is effectively cupped on the paddle between the sloped fore and aft ends  550 ,  552 . A horizontal width W 1  of the sloped aft end  552  may be about 4 inches. A horizontal width W 2  of the sloped fore end  550  may be about 1 inch. It should be appreciated that the plane Ph is preferably normal to the direction of gravity (as indicated by arrow “g”) such that in elevator embodiments in which the elevator is angled forward (e.g., by 7 degrees) the plane Ph defining the angles A 1  and A 2  is angled forward by the same angle (e.g., by 7 degrees). When the paddle  100  rounds the top of the upper sprocket  36 , an upper surface of the sloped aft end  552  is preferably substantially co-planar to a plane (e.g., planes P 1  or P 2 ) intersecting a rotational axis C of the upper sprocket  36  such that the grain is allowed to slide freely off the paddle surface toward the sensor  200  while the paddle  100  rounds the upper sprocket  36 . It should be appreciated that the thickness of the shim  520  and an angle of the upper surface of the shim are preferably selected such that the desired angle of the sloped aft end  552  relative to gravity is achieved both when the paddle  100  is being lifted up the elevator and when the paddle is rounding the top of the upper sprocket  36 . 
         [0021]    A distance T of a gap between the mass flow sensor  202  (e.g., a portion of a lower surface of a sensor plate supported for vertical deflection by deflector arms instrumented with strain gauges) may be between 0.6 and 0.9 inches. It should be appreciated that the surface of the mass flow sensor  202  is preferably curved with a constant radius about the upper sprocket  36  such that the distance T remains constant as the paddle  100  passes the mass flow sensor  202 . Because the distance between the elevator chain  34  and the mass flow sensor  202  is constant for a given combine, the distance between the bolt location and the chain (e.g., the width of the mounting portion between the bolt location and the chain) and the horizontal width of the portion of the paddle  100  extending rearward of the bolt location (e.g., the width of the paddle rearward of the bolt location) is preferably controlled such that the desired gap distance T is achieved for a given combine. The improved paddle  100  of the embodiment of  FIG. 5  may include angled sides similar to the angled sides as illustrated and described in reference to the embodiment of the improved paddle of  FIGS. 6-8 . 
         [0022]    Yet another embodiment of the improved paddle  100  is illustrated in  FIGS. 6-8 . In this embodiment, the paddle  100  includes a sloped fore end  610 , a sloped aft end  620 , sloped sides  630 ,  632  and a floor  640 . The sloped aft end  620  may be omitted such that grain thrown from the paddle  100  is not required to travel up the length of the sloped aft end before leaving the surface of the paddle. Mounting holes  650  enable the paddle to be mounted to the chain  34 , e.g., by bolting to a mounting arm  510  as previously described in connection with the embodiment of  FIG. 5 . 
         [0023]    Referring to  FIG. 7 , the sloped sides  630 ,  632  have a horizontal length L 1 , L 2  which may be between 1 and 2 inches. The floor  640  is located at a depth D from a plane defined by the upper ends of the sloped sides  630 ,  632 . The depth D is preferably between ⅛ and ¼ inch. In some embodiments, the upper ends of the sloped sides  630 ,  632  may have a different height. In such embodiments the depth D is defined by the depth from the horizontal plane of the upper end of the shorter sloped side. 
         [0024]    Referring to  FIG. 8 , sloped aft end  620  is sloped at an angle A 1  with respect to the plane of the floor  630  and the sloped fore end  610  (across the width of the fore periphery of the paddle  100 ), is sloped at an angle A 2  with respect to the plane of the floor  630 . The angle A 1  (which may be less than 10 degrees) is less than the angle A 2  (which may be between 25 and 40 degrees). 
         [0025]    The foregoing description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment of the apparatus, and the general principles and features of the system and methods described herein will be readily apparent to those of skill in the art. Thus, the present invention is not to be limited to the embodiments of the apparatus, system and methods described above and illustrated in the drawing figures, but is to be accorded the widest scope consistent with the spirit and scope of the appended claims.