Abstract:
An improved combine harvester comprises threshing and separating chambers having cover plates on which groups of vanes may be adjusted by individual tie plates utilizing an off-center pivot point for the vanes and a two-bolt system. Said two-bolts being the maximum number of bolts needed to secure each vane wherein one of said bolts is an off-center pivot point while the other of said bolts extends through the cover plate to secure the tie plate for each group of vanes.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates generally to axial flow combines and more particularly to an improved crop flow control and improved vane adjustability in the threshing chambers of the combines. 
       BACKGROUND ART 
       [0002]    Axial flow combines use one or more longitudinally arranged rotors which are rotated in associated chambers, which chambers are partly constituted by threshing and separating concaves. The crop material is subjected to a much longer threshing and separation cycle than in conventional combines and therefore, the efficiency of axial flow machines is greater. A higher degree of separation is reached and the grain losses are reduced. 
         [0003]    The concaves are provided above a cleaning system and constitute the lower portion of the chamber. The top portion of the chamber comprises a curved cover which has, at its inner surface, a set of fins or vanes to guide the crop rearwardly along a spiral path to the end of the threshing and separating zone. 
         [0004]    The pitch angle α, of the vanes, has a direct influence on the time interval the crop remains inside the chamber and hence on the chances for the wheat, beans, or grain to be separated from the straw or chaff. A larger pitch angle will increase the rearward speed of the crop flow, reduce the dwelling time, and increase the portion of wheat, beans, or grain which, rather than being separated through the concaves, is instead deposited onto the field, i.e, “rotor losses”. To the contrary, a smaller pitch angle will reduce the rearward speed, increase the dwelling time, and reduce the “rotor losses”. 
         [0005]    There are three types of axial flow combine rotor designs, i.e., (1) the Case brand model axial flow combine which has a single rotor; (2) the New Holland brand, model axial-flow combine which has a pair of rotors mounted side-by-side; and (3) there are hybrid combines having a transverse threshing cylinder and a pair of axial separating units. 
         [0006]    The hybrid combines are disclosed in, for example, U.S. Pat. Nos. 4,408,618; 4,574,815; 4,611,605; 4,611,606; 4,739,773; 4,875,891; 4,884,994; and 4,969,853. Adjustability of the vanes within the rotor has been an on-going issue in combine designs. Small grains, such as rice, do not have to remain in the separating zone as long as corn, so it is desirable when smaller grains are being threshed to have a steeper angle for the vanes or fins than when threshing, for example, corn. However, it is unduly time-consuming to reposition each vane individually, especially because no crop harvesting can be accomplished during the period of adjustment. 
         [0007]    U.S. Pat. No. 4,244,380, issued to Richard A. DePauw, et al., discloses, a Case brand model single rotor machine having a means for selectively and simultaneously adjusting the position of the vanes to change the rate of movement of the crop material through the casing. A three-bolt type of vane is employed which pivots or swivels at the first or center bolt and which locks down at either end using the two remaining end bolts. The two bolts at either end of the vane each move in their respective helically cut slot and slide over to a detent which secures the bolts and the vane in a different position. A small sheet metal cover plate covers each helical slot. One drawback to this design is that since the detents are under the small cover plates, and hidden from view, one cannot immediately determine the degree to which the vane has been adjusted. Also, grain and debris tend to leak out of the slots when the end bolts are tightened down. Furthermore, there are drawbacks to using this design on the New Holland brand machines with twin rotors because there is less space to access the center bolts and the operator has more difficulty making the other adjustments needed. Additional drawbacks include the fact that the cover plate tends to rotate and will not seat properly against the top cover, perhaps owing to the instability of the pivot bolt. Finally, certain structural weaknesses of this design lead to unwarranted stresses and structural deformation for the vanes. 
         [0008]    U.S. Pat. No. 5,334,093 attempts to address the problems associated with axial separators that comprise a pair of side-by-side axial separator units each having a rotor. Rather than adjust the vanes, they chose to simply replace the top covers and their respective vanes. Therein each axial separator unit is provided with three detachable covers having inwardly projecting spiral vanes. The first cover is provided with at least five spiral vanes. The first vane has an angle of inclination of 45°, the second, third and fourth vanes have an angle of inclination of 30°, and the fifth vane has an angle of inclination of approximately 25°. Accordingly, in small grains, such as rice, the second and third covers each have at least four vanes all with an angle of inclination of approximately 20°. For corn, the second and third covers each have at least four vanes, all with an angle of inclination of approximately 10°. The second and third covers are designated to be interchangeable depending on the crop. However, this system is undesirably time-consuming. 
         [0009]    U.S. Pat. No. 6,447,394 discloses a New Holland brand type rotor design for the twin rotors where the pitch angle of the rotor fins has been optimized with respect to power requirements and rotor losses but are still fixed in design rather than being adjustable. 
         [0010]    An axial flow combine side-by-side rotor design with adjustable vanes that would solve the problems of the prior art would be a significant advancement in the art and would satisfy a longfelt need. 
       SUMMARY OF THE INVENTION 
       [0011]    It is a feature of the present invention that adjustable vanes or fins within a twin rotor system become surprisingly more accessible by holding them in place with only two bolts, rather than three. This is made possible by using one bolt as an off-center pivot bolt, and the other slides in a slot allowing adjustment of the vane. Also, although multiple vanes are tied together by the bars or tie plates to prevent rotation, and the tie bars or plates allow adjustment of multiple vanes at once, it is not necessary to adjust all of the vanes simultaneously. Instead, variation in pitch angle, from one group of vanes to the other, along the length of the rotor, is made possible. 
         [0012]    It is an additional principal feature of the present invention that there are handles on the tie bars or tie plates, which plates are adjustably bolted to the rotor&#39;s top cover on the chamber. The handles facilitate efficient movement. There are also pins on the chamber top cover which, together with curved slots, for receiving each vane&#39;s end bolt, serve to permit visual awareness or indexing of the vane&#39;s α angle. Accordingly, the operator can readily identify and locate the position in which the vanes or fins have been adjusted. The cover plates, off-center pivot end adjustment bolts, tie-bars, etc. are more stable and structurally sound than using prior art three-bolt system, yet more efficient than having replaceable covers and other means used for optimizing power and rotor losses in prior art twin rotor systems. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a semi-schematic side elevation of a combine harvester having axial flow threshing and separating units; 
           [0014]      FIG. 2  is an enlarged fragmentary view of the threshing and separating chamber of an axial flow combine, showing cutout of the adjustable vanes in the top cover and showing cutout of the slats or separating grates on the lower concave assembly of the chamber; 
           [0015]      FIG. 3  is a partial perspective view of the top cover of the threshing and separating chamber; 
           [0016]      FIG. 4  is a rear view of the dual threshing and separating chambers of the combine taken in the direction of arrow I in  FIG. 2 ; 
           [0017]      FIG. 5  is an enlarged partial view of the handle and cover plate lower bolt and indexing slots for the top cover of the threshing and separation chamber; 
           [0018]      FIG. 6  is a perspective view of the details of the bolt, hex nut, and adjusting slot for the tie plate on the chamber top cover; and 
           [0019]      FIG. 7  shows a side view and partial cross-section of the bolt and vane elements. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The terms “grain”, “straw”, and “tailings” are used principally within this specification for convenience as it is to be understood that these terms are not intended to be limiting, thus, “grain” refers to that part of the crop material which is threshed and separated from the discardable part of the crop material which is referred to as “straw”. Incompletely threshed crop material is referred to as “tailings”. Also the terms “forward”, “rearward”, “left” and “right”, when used in connection with the combine harvester and/or components thereof are determined with reference to the direction of forward operative travel of the combine harvester, but again, they should not be construed as limiting. The terms “longitudinal” and “transverse” are determined with reference to the fore-and-aft direction of the harvester and are equally not to be construed as limiting. 
         [0021]    The combine harvester  10  shown in  FIG. 1  of the accompanying drawings is of the axial flow type, wherein crop material is threshed and separated while it is advanced by and along a longitudinally arranged rotor. The combine harvester comprises a chassis or main frame  11  having a pair of driven, ground-engaging front wheels  12  and a pair of smaller, steerable rear wheels  13 . Supported on the main frame  11  are an operator&#39;s platform  14  with an operator&#39;s cab  15 , a threshing and separating assembly  16 , a grain cleaning assembly  17 , and a grain tank  18 . A conventional header  22  and straw elevator  23  extend forwardly of the main chassis  11  and are pivotally secured thereto for generally vertical movement which is controlled by appropriate actuators, such as hydraulic cylinders (not shown). 
         [0022]    The header and the straw elevator  23  supply the cut crop to the threshing end separating assembly  16 . The threshing and separating assembly  16  comprises a pair of juxtaposed, generally cylindrical chambers  26  in which rotors  27  are rotated to thresh and separate the crop received therein, that is to say, the crop is rubbed and beaten between the rotors  27  and the inner services of the chambers  26 . Thereby the grain, seed or the like is loosened and separated from the straw, stalk or cob. The chambers are described in further detail hereinafter. 
         [0023]    Grain which has been separated by the threshing and separating assembly  16  falls onto a first grain pan  30  of the cleaning assembly  17  which further also comprises a pre-cleaning sieve  31 , positioned above a second grain pan  32 , a pair of sieves  33  and  34 , disposed one above the other, and a cleaning fan  35 . 
         [0024]    The grain pans  30 ,  32  and the sieves  31 ,  33 , and  34  are oscillated generally back-and-forth for transporting threshed and separated grain from the first grain pan  30  to the pre-cleaning sieve  31  and the second grain pan  32  and therefrom to the sieves  33 ,  34 . The same oscillatory movement spreads said grain across said sieves  31 ,  33 , and  34 , while permitting the passage of cleaned grain by gravity through the apertures of these sieves. The grain on the sieves  31 ,  33 ,  34  is subjected to a cleaning action by the fan  35  which provides an airflow through said sieves to remove chaff and other impurities such as dust from the grain by making this material airborne for discharge from the machine through an outlet  37  of the straw hood  38 . Clean grain falls to a clean grain auger  40  in a clean grain auger trough  41  and is subsequently transferred therefrom by a grain elevator  44  to the grain tank  18 . Tailings fall to a tailings auger (not shown) in a tailings auger trough  42 . The tailings are transported sideways by tailings auger to a separate rethresher  43  and returned by a tailings conveyor to the cleaning assembly  17  for repeated cleaning action. 
         [0025]    Referring now to  FIGS. 2 and 3 , the lower part of the chamber  26  of the threshing and separating assembly  16  comprises a plurality of concaves or grates  101  allowing the passage of threshed and separated grain to the cleaning assembly  17 . The front portion of assembly  16  has a threshing concave assembly  78 . 
         [0026]    The upper section of the threshing and separating chamber  26  comprises curved cover plates  121  as partially shown in  FIG. 3 . The cover plates  121  extend between and are bolted to the longitudinal profiles  115  and inner side walls  122  of the separating chambers  26  as denoted for example in  FIG. 4 . Each cover plate  121  is provided at its inner surface with a set of parallel vanes  123  which are arranged along spiral paths. The vanes  123  guide the threshed crop material rearwardly as it is rotated by elements (not shown) on the rotor tube  50 . The pitch angle α at which the vanes  123  are disposed is critical with respect to grain loss and power requirement. As this angle defines, for the larger part, the axial speed at which the crop material travels along the confines of the chamber  26 , it also defines the dwelling time of the crop in the separating area, i.e., adjacent the separating grates  101 . A smaller pitch angle α will lower the axial speed of the grain and hence increase the opportunity for the grains to travel through the grates in concave  101  and reach the cleaning assembly  17 . Accordingly, it may be expected that a smaller percentage of the harvested grain will reach the end of the threshing and separating chamber  26  without being separated from the straw and hence be deposited together with the straw through the harvester outlet  37  onto the field. Hence, it may be expected than grain losses at the end of the rotor  27  can be reduced by simply reducing the pitch angle α. 
         [0027]    On the other hand, the pitch angle will influence the energy requirements for the rotation of the rotor  27 . A smaller pitch angle increases the dwelling time and hence the amount of material resent around the rotor tube  50 . Hence it may be expected that a smaller pitch angle α will raise the energy requirements for keeping the rotor  27  rotating at full speed. 
         [0028]    In accordance with the invention and with reference to  FIGS. 2 ,  3  and  4 , a plurality of vanes  123  are disposed in successively spaced apart and substantially parallel relation along the interior of the cover plate  121  throughout the length of the chamber  26 , whereby each vane is a segment of a circle, having a diameter conforming to that of the interior surface of the chamber  26 . Each vane  123  is pivotally mounted on the cover plate  121  by an off-center nut and bolt unit  56  which defines a pivot axis disposed radially relative to the cover plate  121  of chamber  26 . 
         [0029]    A series of tie bars  58  extend longitudinally along the length of the cover plate  121  on the exterior of cover plate  121  and are pivotally secured to the lower ends of separate groups of vanes  123 , preferably two vanes at a time per group, or a sufficient number of vanes to achieve the desired flow characteristics for whatever crops are being contemplated to be threshed. The tie bars are secured to the cover plate which is secured to the vanes by nut and bolt units  60  which extend through respective slots  62  defined through the cover plate  121 . Unlike the prior art, there is no second tie bar mounted on the exterior of the cover plate parallel to and at the top of a first tie bar. Only one tie bar per group of vanes is needed. 
         [0030]    Handles  64  are secured along the length of the tie bars between the nut and bolt units  60 . 
         [0031]    Referring particularly to  FIGS. 5 ,  6  and  7 , nut and bolt units  60  include nut  66  and bolt  67 , which bolt  67  is secured through vanes  123  (which are L-section structures) and on through slot  61  disposed in cover plate  121  and on through tie bar  58  where the bolt  67  together with vane  123 , cover plate  121  and tie bar  58  may all be secured by nut  66 . Also disposed on the cover plate  121  is a pin  75  which is placed to coincide with one of several positions that vane  123  can pivot to so as to allow pin  75  to rest in one of the several slots  74 . This pin  75  thus becomes an indicator or index for the pitch angle α to which the vane has been moved. This allows a casual observer to determine at an instant at which pitch angle each vane has been secured. Thus, it may be possible to set a first set of vanes at and angle of inclination of for example 45°, a second, third, and/or fourth set of vanes at an angle of inclination of for example 30°, and perhaps a fifth set of vanes at an angle of inclination of for example 25°. Or for example, with small grains, such as rice, the second and third series of vanes could be adjusted to have at least four vanes all with an angle of inclination of approximately 20°. In corn, the second and third series of vanes each could be moved, if desired, so that at least four vanes all have an angle of inclination of approximately 10°. The indexing pin would serve as an indicator of the pitch angle for the various sets of vanes without having to change the cover plates of the threshing chamber. Small grains, such as rice, do not have to remain in the separating zone as long as corn, so the adjustments are designed for small grains to have a steeper angle than those designed for grains such as corn. Variation in pitch angles for particular rotor designs and crops has been offered because the optimum angle is not the same for all rotor diameters. As a general rule, the optimum angle decreases when the diameter decreases. There is a well known non-linear relationship between the optimum angle α and the effective rotor diameter D. 
         [0032]    At the end of the threshing and separating assembly  16 , the straw is propelled rearwardly and outwardly. The straw is not deposited directly onto the ground, but ejected onto a slanting guide  125  (shown in  FIG. 1 ), which is attached to the rear of the separating concave assembly  121  of threshing unit  16 . The guide plate  125  is adjacent to a beater assembly  128  which is positioned above the chaffer sieve  33 . The beater assembly  128  further comprises other elements (not shown) for propelling the straw through the outlet  37  at the rear of the combine harvester  10 . The two counter-rotating rotors  27  as shown in  FIG. 4  tend to deposit most of the straw near the center of the guide plate  125 . For machines operating at high capacities, the straw may build up and cause blockages in this portion of a combine harvester  10 . Such blockages evolve quickly to the front of the threshing and separating assembly and may cause a complete blockage of the rotors  27 . Therefore, one is encouraged to make use of the full capacity of the beater assembly  128  and hence to spread out the straw over the full width of the guide plate  125 . 
         [0033]    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.