Abstract:
A thresher for a combine harvester has a concave cage and a rotor disposed within the concave cage. The rotor carries material manipulators that extend outward from the rotor toward the cage to manipulate material in the concave cage as the rotor rotates. One or more air nozzles are provided that direct air outward from the rotor and toward the concave cage. A source of forced air circulates air through the one or more air nozzles.

Description:
TECHNICAL FIELD 
       [0001]    This relates to a thresher used in a rotary-type combine harvester with air nozzles that assist in threshing the grain. 
       BACKGROUND 
       [0002]    Combine harvesters, or combines, are used to reap, thresh, and winnow or separate grain crops. In the threshing process, the grain is separated from the chaff, and in the separation process, the grain and chaff are separated into separate streams. In one common type of combine harvester, a rotor that carries devices to assist in separation, such as rasp bars and blades, sweep, etc., and rotates within a concave grating. The rasp bars help loosen and begin separating the grain from the chaff as it is pushed through the grating. 
         [0003]    In order to increase capacity, rotary combines continue to add increasingly larger engines. However, there are limits to the ability to increase capacity in this way given the geometric shape of the machines due to road travel weight and size restrictions. 
       SUMMARY 
       [0004]    According to an aspect, there is provided a thresher for a combine harvester, comprising a concave cage, and a rotor comprising a cylindrical body having an outer surface, the rotor being disposed within the concave cage and rotating in a first direction about an axis of rotation. The rotor comprises material manipulators carried by the rotor, the material manipulators extending outward from the outer surface of the cylindrical body toward the cage to manipulate material in the concave cage as the rotor rotates. The rotor further comprises one or more air nozzles that direct air outward from the rotor and toward the concave cage, and a source of forced air, such as axial and centrifugal fans in series, that circulates air through the or more air nozzles. 
         [0005]    According to other aspects, thresher may comprise one or more of the following aspects, alone or in combination: the material manipulators may have a leading surface that is angled relative to the axis of rotation such that the plates have a leading surface that leads the material manipulator as the rotor rotates in the first direction; the one or more air nozzles may be adjacent to one or more material manipulators, and may be adjacent to the leading surface of one or more material manipulators; the cylindrical body may define an inner cavity in fluid communication with the one or more air nozzles and the source of forced air comprises one or more blowers that draws air into the inner cavity; the material manipulators may be mounted to a channel that is raised above the outer surface of the cylindrical body, where the channel may act as an air conduit between the source of forced air and the one or more air nozzles and the one or more air nozzles may comprise one or more openings in the channel; and the cylindrical body may comprise openings at both ends to receive air. 
         [0006]    According to another aspect, there is provided a combine harvester, comprising a reaping section that reaps grain crops; a threshing section as described above that receives the grain crops from the reaping section; and a separator section that receives separated grain crops from the threshing section and separates the grain from the chaff. 
         [0007]    According to another aspect, there is provided a method of threshing grain, comprising the step of providing a thresher or combine harvester as described above; and rotating the rotor within the concave cage and circulating air through the one or more nozzles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein: 
           [0009]      FIG. 1  is a side elevation view in section of one end of a cylinder in a cage of a rotary combine representing the air flow. 
           [0010]      FIG. 2  is a perspective view of a fan in the end of the cylinder. 
           [0011]      FIG. 3  is a side elevation view of a cylinder. 
           [0012]      FIG. 4  is a perspective view of a cylinder with air flow. 
           [0013]      FIG. 5  is a perspective view of a cylinder with air flow with the end fan removed. 
           [0014]      FIG. 6  is a schematic of a combine harvester. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring to  FIG. 6 , there is shown an example of a rotary combine  100  that includes a reaper section  102 , a thresher section  104 , and a separator section  106 , each of which are identified generally. Combine  100  is used to reap a crop, then thresh and separate grain from chaff or other material. 
         [0016]    A rotary thresher with air assist, generally identified by reference numeral  10 , will now be described with reference to  FIG. 1 through 5 . Rotary thresher  10  discussed below may be incorporated into the thresher section  104  of combine  100 , but may be used or adapted for use in other types of machinery that may use a rotary thresher. 
         [0017]    Referring to  FIG. 1 , rotary thresher  10  is used to thresh and separate grain from other material that accompanies the grain, such as stalks, husks, etc. Rotary thresher  10  includes a cylindrical rotating body, or rotor  12 , that rotates within a concave cage  14  about a central axis. The cage  14  and rotor  12  may be any suitable design as is known in the art. Common designs typically have an outer diameter of between 20-35 inches, and are designed to rotate between 300-1000 rpm. An example of a suitable cage  14  and rotor  12  is shown in  FIGS. 4 and 5 . Referring to  FIG. 1 , rotor  12  has a cylindrical body  16  with an outer surface  18 , and an inner cavity  20 . Outer surface  18  of rotor  12  carries various devices and tools to assist in the separation of grain from the extra organic material. Aside from those necessary to implement the effect discussed herein, these devices and tools may be modified as is known in the art. Referring to  FIG. 3 , the devices and tools may include rasp bars  22 , sweeps  24 , discharge paddles  26 , and blades or knives (not shown), each of which extends out to, or at least toward, cage  14 . As rotor  12  rotates, these tools will engage the material and improve separation by manipulating the material in different ways. Generally speaking, the material manipulators have a leading surface that is angled relative to the axis of rotation to move the material in a particular direction, represented by arrow  30 . As rotor  12  rotates, a vacuum is created behind sweeps  24 , and an increase in pressure in front of sweeps  24 . The pressure and airflow in front of sweeps  24  is modified by the air pressure exiting nozzles  36 . The specifications, such as size, shape, angle, spacing, etc. may be designed or modified by those skilled in the art. 
         [0018]    Referring to  FIG. 4 , air is delivered into one end of rotor  12  by a blower, depicted as an axial fan  32 , to be directed and controlled to assist separation from within rotor  12 . It will be understood that air may be delivered at both ends if preferred. Referring to  FIG. 1 , two blowers  32  and  34  are shown, where blower  32  is located outside end wall  38  to draw air into rotor  12 , while blower  34  is located within rotor  12  and directs air radially outward into channels  42 . Blowers  32  and  34  may be powered by any suitable means, as will be understood by those skilled in the art. Blowers  32  and  34  may also be mounted in any suitable manner. For example, blower  32  is attached to a rotor stub shaft outside end wall  38 , while blower  34  is located within a sidewall (not shown) attached inside end wall  38  that is sufficiently strong to support blower  34 , while remaining open as much as possible to permit blower  34  to deliver air into channels  42 . 
         [0019]    Referring to  FIG. 1 , rotor  12  is designed to supply nozzles  36  on outer surface  18  of rotor  12  with air by connecting nozzles  34  to a supply of pressurized air. In the depicted example, this is done by opening cavity  20  within cylindrical body  16  of rotor  12 , such that air may be introduced and moved therein by blowers  32  and  34 . A first blower, shown as an axial fan  32  draws air into cylinder  16 , and a second blower, shown as a centrifugal fan  34 , directs the air outward such that it flows toward nozzles  36 . Referring to  FIG. 4 , axial fan  32  may be outside an end wall  38  of cylindrical body  16 , which, referring to  FIG. 5 , has openings  40  to allow the air to enter cavity  20  of cylinder  16 . If one starts from the design of a known type of rotor  12 , this may be achieved by modifying or replacing an existing end wall to have openings  40 . After entering cavity  20 , air may be redirected outward by a centrifugal fan  34  toward nozzles  36 , which are spaced along cylinder  16 , and are shown as being connected to cavity  20  by channels  42 . While a single blower could be used, the use of two blowers  32  and  34  allows a higher degree of control over the air flow, and allows lower horsepower blowers to be used. It will be understood, of course, that various strategies may be used to supply nozzles  36  with air through rotor  12 , including the use of the desired number, style and placement of blowers  32  and/or  34 , or by using a different source of pressurized air in communication with rotor  12 . For example, cylinder  16  may be open at both ends to increase the amount of air available to be drawn into cylinder  16 . Alternatively, there may be flow control devices to control the air pressure from nozzles  36 , such as by making openings  40  in end plate  38  or from cavity  20  to channels  42  adjustable, fan speed, etc. 
         [0020]    Referring to  FIG. 1 , in the depicted example, air flows from inner cavity  20  of cylinder  16  into channels  42 , which may flow along all or a portion of the length of cylinder  16 . As shown, channels  42  are formed using channel iron on outer surface  18  of rotor  12 , and are connected to cavity  20  by channel openings  44  that are fed air by second blower  34 . Cylinder  16  may be modified to allow air to flow from inner cavity  20  of cylinder  16  into channels  42 , and nozzles  36  may then be formed as part of channels  42  used to supply nozzles  36  with air. Preferably, the air pressure is sufficient to supply each nozzle  36  with a similar amount of pressure, although some loss of pressure may be expected as the air flow moves along channels  42  away from second blower  34 . As the grain is separated from the other material, it will exit thresher  10  according to known principles used in known designs. 
         [0021]    Referring to  FIG. 3 , as shown, nozzles  36  are slots that are cut in front of the leading surface of a sweep  24 , and act to apply a shear force to the material being threshed as rotor  12  rotates. Nozzles  36  may also be placed in other advantageous locations, may have other shapes or angles relative to the direction of rotation, or may be used with other types of material manipulators that may be carried by rotor  12 . It is believed that nozzles  36  may be beneficially placed by sweeps  24 , as the primary purpose of sweeps  24  is to move material along cylinder  16 , and that the shear force applied by the air from nozzles  36  may be beneficial when used in connection with this purpose. 
         [0022]    In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be one and only one of the elements. 
         [0023]    The scope of the following claims should not be limited by the preferred embodiments set forth in the examples above and in the drawings, but should be given the broadest interpretation consistent with the description as a whole.