Agricultural combine grain cleaning sieve with adjustable spacing system

A sieve for a grain cleaning system of an agricultural combine, including a system providing enhanced adjustability of spacing, including capacities for quickly and easily varying a number of rows of sieve fingers, spacing between the rows, and angular orientation of the fingers, such that better sieve performance, and cleaning action above the sieve, can be achieved for a particular grain or seed size and other conditions, particularly very large sizes and very small sizes.

TECHNICAL FIELD

This invention relates generally to a sieve for a grain cleaning system of an agricultural combine, and, more particularly, including a spacing system providing enhanced adjustability, including capacities for quickly and easily varying a number of rows of sieve fingers, spacing between rows, and angular orientation of the fingers, for better customizing the sieve for a particular grain size and other conditions.

BACKGROUND ART

U.S. Provisional Application No. 61/197,935, filed Oct. 31, 2008, is incorporated herein in its entirety by reference.

In the harvesting of crops it is desired that the grain or seed, hereafter jointly referred to as grain, be separated from other elements or portions of the crop, such as from pod or cob fragments, straw, stalks, and the like.

Agricultural combines typically have employed a rotary threshing or separating system for separating the grain from such other crop elements or portions. In general, a rotary threshing or separating system includes one or more rotors, which can extend axially (front to rear) or transversely within the body of the combine, and which are partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the rotor within the concave, and the separated grain, together with some particles, such as chaff, dust, straw, and crop residue collectively referred to as material other than grain (MOG), are discharged through the perforations of the concave so as to fall onto a grain bed or pan, or so as to fall directly onto the cleaning system itself.

Cleaning systems further separate the grain from MOG and typically include a fan directing an air flow stream upwardly and rearwardly through one or more fore to aft reciprocating sieves, typically two, including an upper sieve also referred to as a chaffer, which is more open or coarse, and a lower sieve which is more closed or fine. The air flow stream operates to lift and carry the lighter elements of the MOG towards the rear end of the combine for discharge therefrom. Clean grain, being heavier, and larger pieces of MOG, which are not carried away by the air flow stream, will fall onto the surface of the upper sieve where some or all of the clean grain passes through to the lower, finer sieve. Grain and MOG remaining on the sieve surfaces are physically separated by the reciprocal action of the sieves as the material moves rearwardly therealong. Any grain and/or MOG remaining on the surface of the upper sieve are discharged at the rear of the combine, while grain and/MOG on the lower sieve may be conveyed to an internal tailings system for reprocessing.

The quantity of clean grain and MOG passing through the sieves is typically controllable, in part, by varying the opening size of the sieves. To this end, sieves include rows of fingers, each row supported on an elongate element such as a shaft, together referred to as a slat or louver, which is typically rotatable about a longitudinal axis therethrough for setting a sieve size or gap. A typical sieve includes an adjusting member which contacts each of the slats or louvers. Modern combines use 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 adjacent rows of fingers define laterally extending grain passages between confronting surfaces of adjacent rows of fingers. Rotating the longitudinal elements or shafts rotates the rows of fingers through various angular positions, to increase or decrease the opening size of the passages between the adjacent rows. Thus, material passes through the sieve by falling generally vertically through the spaces between the fingers or by entering the passages between the rows and falling through at the angle defined by the angular position of the rows of fingers as the sieve is reciprocated.

Generally, as the rows of fingers are rotated more towards a vertical orientation, the opening size of the passages between the rows is increased to allow more crop material to fall through the sieve through the lateral passages. Also, upward air flow through the sieve will typically be higher as a result of the larger opening size and less restriction. And, because the fingers are more vertical, the grain passages through the sieve are more vertical, so that grain flow through the sieve will be faster and more direct. If the opening size of the passages is too large, a downside is that an increased amount of MOG will be allowed to pass through the sieve. Conversely, as the rows of fingers are rotated more towards a horizontal orientation, the opening size of the passages between the rows is decreased to allow less crop material to fall through the sieve. Because opening size is smaller, upward air flow through the sieve will typically be lower. The grain passages will also be more horizontal, such that grain flow will be longer and less direct, compared to a more vertical orientation. If the opening size of the passages is too small, less MOG is allowed to pass through the sieve, but less clean grain falls through the sieve as well. Therefore, if the sieve passages are opened too much, increased MOG is allowed therethrough, and if the sieve passages are opened too little, less MOG passes therethrough, but grain throughput is reduced.

Often, the sieve setting will be selected for a particular grain variety and other conditions, and the fan speed will be adjusted to achieve an acceptable grain loss level, that is, grain not allowed through the sieve and which is detected as it is discharged past the rear edge of the sieve. In this regard, operators will commonly not be able to achieve optimal grain loss levels of zero or almost zero, and will tolerate greater grain loss than could be attained by adjusting just sieve opening size and fan speed, because minimizing grain loss will often entail opening the upper sieve or chaffer to such an extent that a large amount of MOG will pass therethrough onto the lower sieve, and will be directed by that sieve to the tailings system for reprocessing, sometimes repeatedly.

Many commercially available combine sieves are configured to allow a sufficient range of adjustability of the opening size for accommodating a wide range of crops, including smaller grains such as wheat and rice, and larger grains such as corn, soybeans and other legumes. To have sufficiently large openings for passage of the largest grain sizes, the adjacent slats or louvers must be adequately far apart, and will typically be opened to a relatively upstanding position. In contrast, for the smallest grains, the slats will be positioned more horizontally or closed. As a result, the grain path through the sieve will be longer and less direct, which can negatively affect grain processing and throughput particularly under high yield conditions. A more closed position can also reduce air flow upwardly through the sieve to the region thereabove, which can reduce the cleaning or separating action in that region.

As a proposed solution to the above problems and shortcomings, it is common to utilize different sieves for different crops, a sieve with a larger spacing between adjacent louvers or slats for larger grains, and a sieve with smaller spacing for smaller grains. However, even with multiple sieves available it has been found that it may not always be possible to achieve the best louver spacing or opening size for every crop and crop condition, particularly very large and very small grain sizes.

Ideally while the portion of the flow of crop material including the higher density of grain and MOG is airborne en route to the forward portion of the upper sieve, the flow of air at a significantly higher air flow rate generated by the cleaning fan will be directed therethrough for separating the lighter MOG from the heavier grain such that the lighter MOG will be carried rearwardly over the upper sieve, and the heavier, smaller grain will be allowed to fall onto the upper sieve where it can fall through the spaces between the adjacent fingers of the upper sieve to the lower sieve. Thus, by virtue of the air flow through the airborne flow of crop material, some separation of grain from MOG will occur above the surface of the upper sieve, and some separation will occur on the surface of the upper sieve as a function of the opening size and reciprocation of the upper sieve. That is, under ideal conditions, lighter elements of MOG will be carried by the air flow rearwardly over the upper sieve to be discharged in a desired manner from the combine, heavier elements of MOG will be carried rearwardly by the reciprocating action of the sieves, and grain will fall through the openings of the upper sieve.

When in operation, however, the limited portion of the flow of crop material including the increased density of grain and MOG directed toward the forward portion of the upper sieve having standard spacing between sieve fingers, results in crop material collecting and accumulating on the forward portion of the upper sieve. The accumulation of crop material can build to such an extent as to spill over the forward edge of the upper sieve to the clean grain pan bypassing the lower sieve or into the fan housing. Further, the higher rate air flow stream is unable to pass through the openings of the forward portion of the upper sieve to the extent that the ideal airborne separation above the upper sieve is severely limited or not present at all. As a result the amount of grain cleaned at the forward portion of the upper sieve is severely limited or reduced relative to the ideal situation.

Therefore, what is sought is a sieve for a combine grain cleaning system which overcomes one or more of the problems and shortcomings set forth above.

SUMMARY OF THE INVENTION

What is disclosed is a sieve for a combine grain cleaning system which overcomes one or more of the problems and shortcomings set forth above.

According to a preferred aspect of the invention, the sieve includes a plurality of louvers, each louver including a shaft carrying a plurality of fingers extending sidewardly therefrom at spaced apart locations therealong. Each of the shafts has at least one mounting portion of a predetermined sectional extent for supporting an adjacent region of the louver. The sieve includes a frame bounding a grain flow region, the frame including at least one elongate support element including laterally spaced apart longitudinally extending first and second edges, and a plurality of laterally extending arrays of slots at longitudinally spaced locations along the element. Each of the arrays of slots includes an entry slot disposed along the first edge of the element, a plurality of adjusting slots spaced longitudinally apart and extending toward the second edge, and a plurality of connecting slots extending between and connecting the entry slot and the adjusting slots of the array. Each of the slots is configured for receiving the mounting portion of one or more of the louvers, e.g., has a width marginally larger than the mounting portions of the shafts of the louvers, such that the mounting portions of individual ones of the shafts are receivable in any of the adjusting slots for positioning the louvers in spaced apart relation in the grain flow region. The mounting portions, when so received, are also preferably rotatable within the slots, to allow adjusting the angular orientation thereof for achieving desired grain passage size and air flow through the sieve.

As a result, the spacing between the adjacent ones of the louvers can be adjusted as desired or required for a particular grain or seed size, as well as other conditions. For instance, for a smaller grain size, a more closely spaced relation of the louvers can be selected, which has the advantage of enabling positioning the louvers in a more upright orientation compared to if a larger spacing were used, which can provide more upwardly directed air flow through the louvers, compared to a more laid down orientation. For larger grains, a larger spacing between the louvers can be selected. And, a mixture of smaller spacing for one or more regions of the sieve, and larger spacing for another region or regions, can be selected, for instance, where it is desired to utilize louvers with longer fingers, or where it may be desired for larger items of MOG to pass through the sieve, such as cobs or the like.

According to another preferred aspect of the invention, the arrays are fan shaped, such that the connecting slots extend at different angular orientations between the inlet slot and the adjusting slots. Representative fan shaped arrays can have, for instance, four or more adjusting slots, at desired spacing to provide useful spacing options for an anticipated range of grain or seed sizes. As another preferred aspect, the use of a single entry slot connecting with the adjusting slots via connecting slots, enables the support element to be stiffer and stronger, compared to the other multiple slot constructions, for instance wherein each slot for receiving a louver connects with the edge of the support element. As an advantage of this configuration, more than one, or multiple louvers can be supported within one array of slots.

According to another preferred aspect of the invention, the sieve includes at least one retainer element disposed in connection with the support element in covering relation to the entry slots, for preventing removal of the mounting portions of the louvers therethrough. The fan shaped array facilitates this by providing space on the support element for use of fasteners for attaching the retainer element to the support element.

According to another preferred aspect of the invention, the shafts of the louvers include eccentric adjusting portions, and the sieve comprises an elongate adjusting member disposed for engaging the adjusting portions of the shafts when the mounting portions thereof are disposed in the adjusting slots, respectively, to enable simultaneously rotating the shafts about the axes therethrough, respectively, for varying an angular position of the fingers of the louvers, for adjusting sizes of openings between adjacent ones of the louvers through which grain can pass. The adjustable spacing system of the invention, can be incorporated into any sieve, including, but not limited to, an upper sieve or chaffer, or a lower sieve, for a wide variety of combines.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein like numbers refer to generally like items or features,FIG. 1shows a representative agricultural combine20including a cleaning system22having a sieve24with an adjustable spacing system26constructed and operable according to the present invention. Combine20includes a header28mounted on a front end thereof operable for severing crops from a field during forward motion of combine20and a feeder30operable for conveying the cut crops to a rotary threshing and separating system32within combine20. Generally, threshing and separating system32includes one or more rotors at least partially enclosed by and rotatable within a corresponding number of perforated concaves. The cut crops are threshed and separated by the rotation of the rotor within the concave, and smaller elements of crop material including grain and particles of material other than grain (MOG), including particles lighter than grain, such as chaff, dust and straw, are discharged through perforations of the concave. Larger elements, such as stalks, leaves and the like are discharged from the rear of combine20. Smaller elements of crop material are discharged through the perforations of the concave to a grain pan34disposed beneath threshing and separating system32, as denoted by arrows A, for conveyance as a flow of crop material B, to a forward region36of sieve24, which is an upper sieve of cleaning system22incorporating adjustable spacing system26of the invention.

Referring also toFIGS. 2 and 3, forward region36of sieve24includes a first sieve region38, which will typically be the forwardmost end of the sieve, including rows of first fingers40configured and oriented to define first openings42therebetween. A second sieve region44is disposed rearwardly of first sieve region38and includes rows of second fingers46configured and oriented to define second openings48therebetween. First openings42here are smaller than second openings48in at least the fore and aft direction FA, by dimensions measured and represented by S1and S2, respectively (FIG. 3). Openings42and48define grain flow passages through sieve24, dimensions S1and S2being selected for setting a maximum grain size that can pass through that passage. Cleaning system22includes a fan50operable for directing a flow of air C (FIG. 1) upwardly and rearwardly through openings42and48of upper sieve36, and also through openings of a lower sieve52located below sieve36, in the well known manner. Also in the well known manner, cleaning system22also includes apparatus (not shown) operable for reciprocatingly moving sieves36and52, as well as grain pan34in the fore and aft direction FA, for propelling material thereon rearwardly.

As best illustrated inFIG. 1, in operation, harvested grain will typically be delivered by pan34onto forward region36of sieve24, in a relatively heavy stream or flow. This grain will typically be mixed with MOG, much of which will typically be lighter than the grain. As part of the grain cleaning process, air flow C will flow through this falling material, with the intent that the heavier grain mostly fall onto region36(comprised of fingers40as shown inFIGS. 2 and 3), and if sufficiently small in size, will pass downwardly through openings42, to lower sieve52. The lighter MOG will be carried by the air flow rearwardly through a region54above sieve24and be discharged from the rear of combine20. Some of the heavier MOG will also drop onto region36, or onto second region44, and can pass through openings42or48if sufficiently small, and otherwise will be carried rearwardly by the reciprocating action of sieve24and fall over the rear edge thereof. Grain and smaller MOG that passes through sieve24will either be blown rearwardly though a space55between the sieves and discharged, or be carried rearwardly on sieve52and reprocessed, and the remaining grain will pass through that sieve for collection, in the well known manner.

As noted in the Background section, grain or seed sizes harvested by combines such as combine20commonly range from the smallest wheat and rice, to the largest corn, soybeans and other legumes. Providing sieves, particularly upper sieves, for accommodating such wide ranges of sizes has typically entailed using one sieve for smaller grain sizes and another for larger sizes. However, even this approach has been less than satisfactory in many instances, particularly for the smallest and largest grain sizes, and wherein the fingers must be laid down a significant amount to achieve desired sizing.

Referring also toFIGS. 4 and 5, adjustable spacing system26of the present invention addresses this problem, and eliminates or reduces the need for providing alternative sieves for different grain sizes. According to the invention, at least24is constructed of a plurality of louvers56and58, each louver56and58including a shaft60of metal wire or other suitable construction carrying a plurality of fingers40or46, respectively, of suitable material such as sheet metal or plastics extending sidewardly therefrom at spaced apart locations therealong. Each shaft60has at least one mounting portion62of a predetermined sectional extent SE (FIG. 5) for supporting an adjacent region of the louver. The sieve includes a frame64of sheet metal or other suitable construction bounding a grain flow region66, frame64including at least one elongate support element68of sheet metal or the like including laterally spaced apart longitudinally extending first and second edges70and72, and a plurality of laterally extending arrays of slots74at longitudinally spaced locations along support element68.

Each of the arrays of slots74includes an entry slot76disposed along first edge70of support element68, a plurality of adjusting slots78spaced longitudinally apart and extending toward second edge72, and a plurality of connecting slots80extending between and connecting entry slot76and adjusting slots78of the array. Each of the slots76,78and80is configured for receiving a mounting portion62of one or more of louvers56and58, that is, it has a width W (FIG. 5) marginally larger than sectional extent SE of mounting portions62, such that mounting portions62of individual ones of shafts60are receivable in any of adjusting slots78for positioning the louvers in spaced apart relation in grain flow region66.

Mounting portions62, when so received, are also preferably rotatable within slots76,78and80, to allow adjusting the angular orientation of fingers40and46for achieving desired grain passage size, e.g., increasing or decreasing S1and S2, as well as affecting air flow through the sieve. To achieve this, shafts60preferably include adjusting portions82, which here are eccentric to axes X through shafts60(FIG. 4), and sieve24includes an elongate adjusting member84disposed for engaging adjusting portions82when mounting portions62are disposed in adjusting slots78, respectively, to enable simultaneously rotating shafts60about axes X therethrough, respectively, for varying an angular position of the fingers of the louvers, for adjusting sizes of openings S1and S2. Adjusting member84is preferably an elongate member of sheet metal or other suitable construction and includes upwardly facing slots positionable in alignment with adjusting slots78for jointly receiving adjusting portions82, there being a sufficient number of slots in the adjusting member to enable selecting any of the adjusting slots78, and adjusting member84being movable longitudinally in direction FA for effecting the rotation of shafts60.

Sieve36includes a retainer element86disposed in connection with support element68, of suitable construction such as sheet metal, disposed in covering relation to entry slots76, for preventing removal of shafts60therethrough and capturing the shafts in the selected adjusting slots78. Retainer element86can be suitably held in place, such as with threaded fasteners88which pass through holes90through support element68(FIG. 5), so as to be easily removable to enable repositioning or reconfiguring the louver arrangement. Retainer element86also covers adjusting portions82of the louvers.

Referring also toFIGS. 6,7,8and9, an attendant advantage of adjustable spacing system26of the present invention is the ability to select the spacing, and number, of rows of louvers, such as louvers56and58, of sieve24, as well as the mix of louvers. Thus, examiningFIGS. 6 and 7, louvers56are disposed in every third, and every other adjusting slot78of support element68, respectively, to provide about equal spacings S1. However, as illustrated here and inFIGS. 8 and 9, which are top views of the setups ofFIGS. 6 and 7respectively, the spacings S1are achieved with louvers56oriented at different angles, that is a more laid down angle inFIGS. 6 and 8, and a more upstanding angle inFIGS. 7 and 9. InFIG. 7louvers58are shown disposed in every fifth slot78to illustrate even larger spacing, and the ability to mix spacings and louver types. By comparing the spacings illustrated inFIGS. 8 and 9from the top, it can be seen that that differences in the grain flow passages through the louvers can be quite substantial. Also, it can be observed inFIGS. 7 and 9, that relatively small spacings can be achieved with more upright orientations of the louvers, to facilitate a more upwardly directed, and less restricted, air flow therethrough (as opposed to more rearward flow), to facilitate cleaning and separation of grain from MOG in the region above the sieve. A more upright louver orientation will also provide a more vertical grain flow path, which will be shorter, and be facilitated more by gravity, compared to a more laid down orientation, for better grain throughput. Also, because by using a greater concentration of fingers to achieve smaller grain flow passages, if required or desired, the fingers can be positioned in a more laid down orientation than shown inFIGS. 7 and 9, to achieve even smaller sizing.

As another advantage illustrated inFIG. 7, by using arrays74including a single entry slot76in connection with several adjusting slots78, multiple louvers56and58can be inserted into respective arrays74, so that fewer breaks in the upper edge of support element68, which enables it to be stiffer and to provide space for placement of fasteners88.

As still another advantage, regions of a sieve, e.g., a rear end portion, can have significantly fewer louvers, to provide large openings therebetween, for instance, to allow passage of corn cobs therethrough. Thus as an example of one contemplated sieve configuration for corn, a forward region36of a sieve could be provided with a first density of louvers56such as illustrated inFIGS. 6-9, a second sieve region could have a lower density of louvers56or58, and a third rearmost region could have an even lower density, to enable whole cob flow through the sieve. Then, for other crops or conditions, the same sieve could be reconfigured differently and more advantageously for that crop and/or those conditions.

Referring also toFIGS. 10 and 11, alternative apparatus92for adjustable spacing system26of the invention is shown. Here, a representative louver56or58including fingers40or46is shown including a shaft60having a non-round shaped end portion94, which here is rectangular. End portion94is cooperatively receivable in a correspondingly shaped receptacle96projecting from one side of a louver support element98. Louver support element98has an opposite side including a shaft100projecting therefrom, which is cooperatively received in any of an array of holes102in a side rail104of frame64of sieve24. Shaft100includes a detent106on the terminal or free end thereof for retaining it in the selected hole102, while allowing rotation of louver support element98, and a louver56or58supported thereby, about a pivotal axis X through the shaft, as denoted by arrow R inFIG. 10. Shaft60can be retained in receptacle96in any suitable manner, such as by a suitable spring108, a detent, pinned connection, frictional fit, or the like. Louver support element98additionally includes an adjusting portion110offset from axis X, configured for connection to an adjusting member112, e.g., by a pinned connection114, for adjustably rotating element98and louver56or58about axis X and holding them in a selected angular orientation. Pins116are provided at intervals along adjusting member112, corresponding to the locations of the alternative holes112in rail104, to facilitate adjustability of any desired or required number of louver support elements98used to achieve desired louver spacing, and the angles of the louvers can be adjusted using the adjusting member112, essentially in the above described manner with regard to adjusting member84, e.g., movement in direction FA, with similar advantages as just explained.