Abstract:
An adjustment mechanism for opening size of sieve segments of the cleaning system of an agricultural combine disposed in end to end relation, which allows jointly adjusting the sieve sizes, or separate adjustment, and which allows easy and convenient removal and reinstallation of the sieve segments. The mechanism includes an adjusting element in connection with each of the sieve segments, which is movable in a predetermined manner for effecting adjustments in the opening size thereof. Connecting elements connect together the adjusting elements for joint adjustment, and are disconnectable to allow individual adjustment. The predetermined manner of movement can be, for instance, a simple rotational movement, and the connecting elements can include and elongate connecting element, such as a rod or tube which can extend over a substantial portion of the sieve segments.

Description:
TECHNICAL FIELD 
   This invention relates generally to an adjustment mechanism or system for a grain cleaning sieve or sieves of a cleaning system of an agricultural combine, and more particularly, to a mechanism which allows selectively jointly or separately adjusting the sieve opening size or position of discrete segments or regions of a sieve. 
   BACKGROUND ART 
   It is well known to provide a sieve or sieves in the grain cleaning system of an agricultural combine. Typically, the cleaning system will consist of two sieves, an upper or coarser sieve or chaffer located below the threshing mechanism or separator of the combine and having larger sieve openings for the passage of grain and smaller pieces of plant material therethrough but relatively little of the larger chaff, and a lower finer sieve located below the chaffer for receiving the grain and smaller pieces of plant material therefrom and having smaller sieve openings for passage of the grain therethrough but relatively little of the plant material. The collected and cleaned grain, once through the sieves is then typically transported by conveyor or other means to a clean grain tank or bin on the combine, or to an accompanying grain receiving vehicle. The opening sizes of the chaffer and sieve are important parameters for controlling the amount or yield of grain that is recovered by the combine as opposed to discharged therefrom with the chaff and other unwanted plant material and crop residue. Accordingly, the chaffer and sieve opening sizes are typically set at the commencement of the harvesting operation, and may be reset at times during the harvesting operation, to achieve a desired crop yield rate. 
   A typical sieve construction includes a plurality of elongate parallel, pivotally mounted slats, each slat including a plurality of longitudinally spaced upwardly extending inclined fingers, the slats being pivotable through a range of open positions angularly oriented to horizontal for providing a corresponding range of openings or spaces between the fingers of adjacent ones of the slats. A typical sieve includes an adjusting member which contacts each of the slats, and a linkage and/or cable arrangement connected between the adjusting member and one or more manually or automatically movable adjusting elements or adjustors, in the latter instance, which can be moved by an actuator driven by an electrical, fluid, or other controller for moving the linkage or cable arrangement and member and thus changing the angular orientation of the slats and as a result, the opening size. The typical controller includes at least one processor operated by stored commands and/or inputs for controlling an electrical drive motor or the like for moving the actuator. An input device such as a push button or keypad and a display device are typically located in the operator cab of the combine for changing and showing the chaffer and sieve settings. 
   As combines have increased in capacity, the sieves have grown in size. Sieves are also typically removable for cleaning, service, and the like. Because of the larger size of the sieves, it is desirable for them to be divided into separately removable segments, for instance, a front segment and a rear segment, or a plurality of segments arranged in end to end order. And, because of the larger size, and other factors, such as uneven wear, it can be difficult to evenly adjust a sieve evenly across the extent thereof. Or, it may be desirable to adjust the segments differently, to achieve a desired cleaning effect. For instance, it may be desirable to set the opening size of the more frontward segments or segments at a more closed setting and the more rearward segment or segments more open, as towards the front end of the sieve there is typically more loose grain present, and toward the rear end there is typically more material other than grain such as larger pod or cob fragments, and the like. 
   As a result, what is sought is an adjusting mechanism for a sieve which does not increase the overall size or operating envelope of the sieve. It is also sought to provide a sieve which allows separate or joint adjustment of adjacent sieves or sieve segments, and also sieves of different types. Still further, the adjusting mechanism should allow for the removal of the sieves, and should be durable and long lasting. 
   SUMMARY OF THE INVENTION 
   According to the present invention, a sieve adjustment mechanism for controlling opening sizes of a plurality of sieve segments of a cleaning system of an agricultural combine, which provides one or more of the features and advantages sought above, and overcomes many of the problems and shortcomings identified above, is disclosed. 
   According to a preferred aspect of the invention, the mechanism is adapted for adjusting opening sizes of first and second sieve segments disposed in edge to edge or end to end relation. The mechanism includes a first adjusting element disposed so as to be movable in a predetermined manner for adjusting the opening size of the first sieve segment, and a second adjusting element disposed so as to be movable in a predetermined manner for adjusting the opening size of the second sieve element. The mechanism includes an actuating element in connection with the first adjusting element and operable for moving the first adjusting element in the predetermined manner, and first and second connecting elements disposed in connection with the first and second adjusting elements, respectively, the connecting elements being connectable for connecting the first and second adjusting elements together such that movement of the first adjusting element in the predetermined manner will cause movement of the second adjusting element in the predetermined manner, and the connecting elements being disconnectable for allowing the first adjusting element to be moved in the predetermined manner without causing movement of the second adjusting element. 
   As a result, for instance, the opening sizes of the sieve segments can be adjusted together, to the same opening size, and left at that size, or they can be adjusted together then the connecting elements disconnected, such that the opening size of the first sieve segment can be adjusted differently, as desired or required for a particular application. 
   According to another preferred aspect of the invention, the connecting elements include a rod in connection with one of the adjusting elements and a tube in connection with another of the adjusting elements, an end portion of the rod being disposed or cooperatively received in the tube and connectable thereto, or cooperatively engageable therewith, for movement of the rod therewith, and the rod being disconnectable from the tube to allow independent movement thereof, and the separate adjustment of the opening sizes. For instance, the rod and the tube can be connected together using a pinned connection, the pin being removable to allow the separate adjustment of the opening size of the first sieve segment, and also the removal of the sieve segments from the combine for cleaning or other purposes, as desired or required. Thereafter, if the sieve segments are reinstalled, or it is desired to again adjust the second sieve segment, the pin can be replaced. 
   A preferred manner of movement of the adjusting elements is a rotational movement, which can be effected by manual or automatic actuation, such as by a hand operated handle, or an electronic, fluid or other controlled actuator or controller. And, the adjusting elements can include, for instance a female threaded member such as a nut on a rotatable male threaded member such as a threaded rod or screw so as to be moved longitudinally by rotation of the rod or screw, and a finger engageable with slats or an adjusting member of a sieve movable by the longitudinal movement of the nut, for adjusting the opening size. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a simplified side elevational view of an agricultural combine including a sieve adjustment mechanism according to the present invention; 
       FIG. 2  is a simplified perspective view of sieves of a cleaning system of the combine of  FIG. 1 , showing the adjustment mechanism in connection with first and second sieve segments of the cleaning system; 
       FIG. 3  is another simplified perspective view of the sieves and adjustment mechanism, illustrating alternative actuators for the adjustment mechanism; 
       FIG. 4  is still another simplified perspective view of the sieves and adjustment mechanism, illustrating the second sieve segment removed from the cleaning system, and arrows illustrating reinstallation thereof; 
       FIG. 5  is a simplified perspective view of a sieve including three groups of slats and adjustment mechanisms therefor according to the invention; 
       FIG. 6  is a fragmentary perspective view of a first adjusting element and connecting elements of the mechanism of the invention, illustrating making of a pinned connection of the connecting elements for connection of the first adjusting element to a second adjusting element; 
       FIG. 7  is a fragmentary side view of the first adjusting element and connecting elements of  FIG. 6 ; and 
       FIG. 8  is another fragmentary side view of the first adjusting element and connecting elements, showing the adjusting element moved for changing the opening size of a sieve. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, in  FIG. 1  a conventional agricultural combine  10  is shown, illustrating generally the location of a sieve adjustment mechanism  12  in connection therewith and constructed and operable according to the teachings of the present invention. Agricultural combine  10  generally includes a threshing mechanism or separator  14  operable for receiving crop material from a harvesting mechanism (not shown) on a front end  16  of combine  10 , separator  14  being operable for separating smaller grains, seeds, pods and related plant material from larger stalks, stems, leaves, husks and other elements of the crop material, as well as vines, weeds and the like which may be present in the harvested crop material. The smaller material falls from separator  14  into one or more augers  18  disposed below separator  14 , which collect the smaller material and convey it to a cleaning system  20 . 
   Referring also to  FIGS. 2 ,  3 ,  4 ,  5 ,  6 ,  7  and  8 , cleaning system  20  includes an upper, coarser sieve, also known as a chaffer  22 , positioned for receiving the material from the auger or augers, and a lower, finer sieve  24  which receives grain or seeds which pass through chaffer  22 . Sieve  24 , in turn, separates or cleans the grain or seed from the remaining other material, such as pod fragments and the like, for collection by a lower auger  26  ( FIG. 1 ) which conveys the clean grain or seeds to an elevator which conveys the clean grain or seeds upwardly to a clean grain bin  28  (also  FIG. 1 ). Chaffer  22  and sieve  24  are vibrated or reciprocated during operation by suitable means (not shown) for facilitating sifting of the crop material therethrough. Material which does not pass through is moved rearwardly on chaffer  22  or sieve  24  by the vibration or reciprocal action and is either blown or drops from the rear end thereof through an opening in the rear of combine  10  or into a return auger to be carried back to separator  14  or chaffer  22 . 
   Referring in particular to  FIGS. 6 ,  7  and  8 , chaffer  22  and sieve  24  are each of well known construction, as represented by chaffer  22 . Chaffer  22  includes a plurality of elongate, horizontally extending slats  30 , each slat being pivotable about a sidewardly extending generally horizontal pivotal axis  32 . Each slat  30  is composed of a plurality of parallel, longitudinally spaced upward and downwardly inclined fingers  34 , the fingers  34  of adjacent ones of slats  30  defining sieve openings therebetween, represented by distance X in  FIG. 7 , for the passage of only plant material of a desired maximum size therethrough, i.e., clean grain. Slats  30  are simultaneously pivotable about respective pivotal axes  32  through a range of pivotable positions for varying the opening size X of the sieve in the well known conventional manner, as denoted by arrows A. In this regard, slats  30  would be pivoted in a counterclockwise direction to increase the opening size X, and pivoted in the clockwise direction for decreasing the opening size X. Sieve  24  is adjustable in a similar manner. 
   Sieve adjustment mechanism  12  is operable for simultaneously moving slats  30  through a predetermined range of pivotal positions for varying the opening size of chaffer  22 , and for holding slats  30  at a position corresponding to a desired or selected opening size. Referring also to  FIG. 3 , to accomplish this, mechanism  12  preferably includes at least one actuator, such as, but not limited to, a conventional manual actuator  36  which can be, for instance, a hand operable handwheel or handle, or an automatic actuator, such as, for instance, an electric rotary actuator  38 , a fluid controlled actuator, or the like. Actuators  36  and  38  can be connected by a suitable mechanical connecting element such as by a rotatable actuating rod  40 , or one or more cables and/or linkages, to adjusting mechanism  12 . 
   Here, it should be noted and observed that chaffer  22  is divided into segments, including a more rearwardly located first sieve segment  42 , and a more forwardly located second sieve segment  44 , located in edge to edge or end to end relation on and supported by a rectangular support frame  46 . Each of the sieve segments  42  and  44  includes a plurality of the slats  30  described above, and is removable from frame  46  for service, cleaning and/or other desired or required purposes. Each sieve segment  42  and  44  includes a plurality of fore and aft extending ribs  48  connected between inwardly located cross members, represented by rear crossmember  50  of sieve segment  42  in  FIGS. 7 and 8 , which ribs  48  support slats  30  in parallel side by side relation for the pivotal movement just discussed, in connection with a plurality of elongate crank rods  52 . Crank rods  52  are retained by and engaged with an elongate, fore and aft extending adjusting member  54  extending along one of ribs  48 . Adjusting member  54  is movable in the fore and aft direction, as denoted by arrow B in  FIG. 7 , for rotating crank rods  52  to pivot slats  30  for varying the opening size of the sieve segment  42  or  44 . Movements to the right will effect counterclockwise movements of crank rods  52  and slats  30  to increase opening size X, and movements to the left will effect clockwise movements, to decrease opening size. 
   Sieve adjustment mechanism  12  is configurable so as to be operable for jointly effecting such rotational movements of slats  30  of both first sieve segment  42  and second sieve segment  44 , or effecting such rotational movements of slats  30  of only first sieve segment  42 , such that the opening sizes of the two sieve segments can be the same, or different, as desired or required for a particular application. To provide this capability, mechanism  12  includes a first adjusting element disposed on first sieve segment  42 , and a second adjusting element  58  disposed on second sieve segment  44 . Each of adjusting elements  56  and  58  includes a pair of mounting blocks  60  fixedly mounted to a rib  48  in fore and aft spaced relation, by suitable fasteners such as bolts or the like. Each pair of blocks  60  supports and retains a male threaded member  62 , such as a threaded rod or screw, for rotation in place therebetween, threaded member  62  of first adjusting element  56  also including rod  40 , so as to be rotatable by manual actuator  36 , or by an automatic actuator, such as electric rotary actuator  38 . A female threaded member  64 , which can be a nut or the like, is threadedly engaged with each male threaded member  62 , respectively, and includes a downwardly extending adjusting tab  66 . Each adjusting tab  66  is positioned to engage adjusting member  54  of the respective sieve segment, and is movable in the fore and aft directions by movements of male threaded member  62  of the adjusting element  56  or  58  in a predetermined manner, which, here, preferably is a rotational movement. Male threaded members  62  of adjusting elements  56  and  58  are connected together by connecting elements  68  and  70  for joint movement in the predetermined manner, that is, preferably for joint rotational movement, such that opening size of sieve segments  42  and  44  will be adjusted simultaneously by the rotational movement of the actuator, such as manual actuator  36  or rotary actuator  38 . Alternatively, connecting elements  68  and  70  are disconnectable, to allow adjustment of opening size of sieve segment  42  only. As a result, sieve adjustment mechanism  12  of the invention can be utilized for jointly adjusting opening size of front sieve segment  42  and rear sieve segment  44 , then connecting elements  68  and  70  can be disconnected, to allow singly adjusting opening size of just front sieve segment  42 . 
   Connecting element  68  preferably comprises a short rod which is an extension of male threaded member  62  which extends forwardly beyond forwardmost mounting block  60  of first adjusting element  56 , and connecting element  70  preferably comprises an elongate tube, or a rod, the rear end of which is open so as to cooperatively receive connecting element  68 . Connecting elements  68  and  70  are preferably connectable together for joint movement in the predetermined manner, preferably rotation, using a pin  72  insertable through alignable holes in elements  68  and  70 , and conveniently retainable therein, by suitable means such as a detent member, cotter pin, or the like. As a result, removal of pin  72  allows rotation of connecting element  68  independently of connecting element  70 , for effecting the singular adjustment of opening size of first sieve segment  42 . Similarly, reinstallation of pin  72 , as illustrated in  FIG. 6 , allows joint adjustment of opening size. Additionally, with pin  72  removed, either or both of sieve segments  42  and  44  can be separately removed from support frame  46 , as illustrated by removed sieve segment  44  in  FIG. 4 , the sieve segment being reinstallable in support frame  46 , as illustrated by the arrows. Here, connecting element  70  is also shown disconnected from adjusting element  58  on sieve segment  44  removed from frame  46 , to facilitate ease of removal of sieve segment  44  from the combine. In this regard, it should be noted that connecting element  70  can be connected to male threaded member  62  of second adjusting element  58  in any suitable manner, such as, but not limited to, by use of an additional connecting element  68  and pin  72  (not shown), to allow removal of sieve segment  44  only, if desired. Further in this regard, connecting elements  68  and  70  can be configured to allow connection thereof in only one, or in a limited number of, rotational positions one relative to the other, such that when reconnected, the opening setting of a selected one of the sieve segments  42  or  44  can be duplicated on the other of the sieve segments  42  or  44 . 
   It is contemplated that the sieve adjustment mechanism of the invention can be utilized for providing more than just two different opening sizes for two or more ranges or sets of the slats of a sieve segment, such as sieve segments  42  and  44 , or of one or more additional sieve segments, simply by using additional adjusting elements, as illustrated by use of third adjusting element  74 , in connection with an additional adjusting member, on one or more of the sieve segments, such as first sieve segment  42 . Thus, in this illustration first sieve segment  42  will include two of the adjusting members  54  ( FIGS. 7 and 8 ), adjusting element  56  being in connection with one of the adjusting members, and adjusting element  74  being in connection with the other of the adjusting members, such that the slats associated with the respective adjusting members (here grouped as slats  30  and  30 A,  FIG. 5 ) can be adjusted to different opening sizes. This is with respect to one another, and also with respect to the opening sizes of the slats of the other sieve segment  44 , denoted as slats  30 B. Adjusting element  74  is connectable between adjusting elements  56  and  58  utilizing an additional set of connecting elements, illustrated by connecting element  70 . Thus, with the connecting element  56 ,  58  and  74  connected together by connecting elements of the invention, the opening sizes of the groups of slats  30 ,  30 A and  30 B can be jointly adjusted, and either left at the same setting, or then differently adjusted, simply by disconnection of the connecting elements therebetween. As an illustration, after joint adjustment of the three groups of slats, connecting element  70  between adjusting elements  58  and  74  can be disconnected, to allow readjusting opening size of groups of slats  30  and  30 A together. Then, connecting element  70  between adjusting elements  56  and  74  can be disconnected, to allow separately adjusting opening size of slats  30 . 
   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 embodiments 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.