Abstract:
A sieve retainer for an agricultural combine which is more accessible, particularly from the rear of the combine, which provides improved access to, and removal and replacement of the sieve and prevents loss of sieve retaining hardware.

Description:
TECHNICAL FIELD 
     This invention relates generally to a retainer for a grain cleaning sieve or sieves of a cleaning system of an agricultural combine, and more particularly, to a retainer which is more accessible, particularly from the rear of the combine, and which provides improved access to, and removal and replacement of the 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 elements 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 elements 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. 
     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 sieve may be adjusted to a desired opening at the commencement of the harvesting operation, and may be reset at times during the harvesting operation, either mechanically or automatically, to achieve a desired crop yield rate. It may also be necessary to access the sieve, during or after the harvesting operation, to clear any chaff, plant material, debris, or the like that may become lodged in the spaces or openings in the sieve. 
     It may also be necessary to remove the sieve for cleaning, service, replacement, and the like. Generally the sieves are mounted and retained in the combine using hardware, such as nuts and bolts accessed from the side of the combine. Accordingly, this mounting arrangement requires opening a side panel on the combine, locating the retaining hardware on the inside of the sieve support structure, which may or may not be visible or readily accessible from the outside of the combine, and removing the retaining hardware. Then the procedure is repeated on the opposite side of the combine. Once the retaining hardware is removed from both sides of the combine, the sieve may be removed from the rear of the combine by lifting the sieve from its support structure and then pulling it from the rear of the combine. The procedure must be reversed to mount and retain the sieve when replaced. Since the retaining hardware (nuts and bolts) is removed from the support structure prior to removing the sieve, these small pieces of hardware can easily be dropped and/or lost during subsequent cleaning or service of the sieve resulting in delay and additional down time for the combine. Also, in some instances, the upper sieve, or chaffer, must be removed whether or not it needs maintenance, just to gain access to the lower sieve. Finally, removal and/or replacement of the sieve by lifting and/or lowering the sieve relative to its support structure can be difficult and undesirable. 
     As a result, what is sought is a sieve retainer which is more accessible, preferably solely from the rear of the combine, and which provides improved and easier access to, and removal and replacement of the sieve without significant lifting. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a sieve retainer which is more accessible, particularly from the rear of a combine, and which provides improved access to, and removal and replacement of the sieve, 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, an elongate sieve support structure is supported on the combine for reciprocating movement longitudinally in the first and second directions. The sieve support structure includes side retainers extending longitudinally in the first and second directions and cooperatively engages first and second side edges of a sieve, respectively, supporting the sieve along the first and second side edges for the reciprocating movement in the first and second directions with the support structure. An end retainer structure is disposed adjacent to a second end peripheral edge of the sieve. It is configurable in at least one locking mode in cooperative engagement with the second end peripheral edge of the sieve for retaining and limiting movement of the sieve relative to the sieve support structure, and is releasable in at least one unlocking mode for allowing movement of the sieve in the second direction longitudinally relative to the sieve support structure and the side retainers for allowing removal of the sieve in the first direction longitudinally relative to the sieve support structure and the side retainers. 
     According to another aspect of the invention, the end retainer structure has elongate members attached to the sieve support structure disposed adjacent to the second end of the sieve, receiving members movable in the first and second directions relative to the elongate members, an elongate element connecting the receiving members and abuttingly engageable with the second end peripheral edge of the sieve, and detent elements retained on and positionable longitudinally along the elongate members. When the end retainer is configured in a locking mode, the elongate members extend through the receiving members and the detent elements are locked against the receiving members causing the elongate element to be fixedly held thereby against the sieve. When the end retainer is configured in the unlocking mode, the elongate element is separated from the sieve to allow movement of the sieve longitudinally relative to the sieve support structure, and the detent elements remain on the elongate members. 
     According to preferred embodiment of the invention, the detent element has a first transverse extent larger than a transverse extent in a predetermined direction of the receiving member. The detent element can be oriented so that the first extent extends in the predetermined direction of the receiving element to prevent the movement of the sieve longitudinally relative to the sieve support structure. The detent element also has a second transverse extent smaller than the transverse extent in the predetermined direction of the receiving member. The detent element can be oriented so that the second extent extends in the predetermined direction of the receiving element to allow the movement of the sieve longitudinally relative to the sieve support structure. The detent element also includes a locking element configured for fixedly holding the detent element at a position along the elongate member. The detent element may also include a tab configured for cooperative engagement with a notch in the receiving member when the detent element is fixedly locked against the receiving member. 
     In a preferred embodiment of the invention the end retainer comprises a rake of the combine. Accordingly, removal of the rake, allows access to the sieve. It is also likely that removal of the rake will allow access to, or removal of, one sieve without necessitating removing the other sieve. The invention may be utilized for the upper sieve, the lower sieve, or both. 
     As a result, the sieve retainer, with its associated hardware, is more accessible, particularly from the rear of the combine. The invention provides improved access to, and removal and replacement of the sieve, and decreases the likelihood that sieve retaining hardware will be dropped or lost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified side view of an agricultural combine including a rear accessible sieve retainer according to the present invention; 
         FIG. 2  is an example of a simplified, exploded view of a prior art sieve and rake attachment area of an agricultural combine; 
         FIG. 3  is a simplified perspective view of a sieve retainer of the present invention; 
         FIG. 4  is a simplified perspective view of the sieve retainer showing one side of the retainer in a locking configuration according to the present invention; 
         FIG. 5  is an exploded view of a receiving member and a portion of the detent element according to the present invention; 
         FIG. 6  is an enlarged perspective view of a portion of the rear sieve retainer attached to the sieve support structure; 
         FIG. 7  is a cross section view taken at line a-a of  FIG. 4  according to the present invention; 
         FIG. 8  is a rear view of a portion of the sieve retainer structure as shown in  FIG. 4 ; 
         FIG. 9  is a simplified perspective view of the sieve retainer at an intermediate point between the locking configuration and an unlocking configuration according to the present invention; 
         FIG. 10  is a simplified perspective view of the sieve retainer showing one side of the retainer at another intermediate point between the locking configuration and the unlocking configuration according to the present invention; 
         FIG. 11  is a simplified perspective view of the sieve retainer at yet another intermediate point between the locking configuration and the unlocking configuration according to the present invention; 
         FIG. 12  is a simplified perspective view of the sieve retainer showing one side of the retainer in the unlocking configuration according to the present invention; 
         FIG. 13  is a simplified rear view of the combine showing both upper and lower sieves retained using the rear accessible sieve retainer according to the present invention; 
         FIG. 14  is a simplified rear view of the combine showing the sieve retainer removed from the upper sieve and the lower sieve retained using the rear accessible sieve retainer according to the present invention; and 
         FIG. 15  is a simplified rear view of the combine with the lower sieve removed without removing the upper 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 retainer  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 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 (not shown) disposed below separator  14 , which collect the smaller material and convey it to a cleaning system  20 . 
     Cleaning system  20  includes an upper, coarser sieve, also known as a chaffer  22 , positioned for receiving the material from the auger, augers or threshing mechanism, and a lower, finer sieve  24  which receives grain or seeds which pass through chaffer  22 . Sieves  22 ,  24 , in turn, separate or clean the grain or seed from the remaining other material, such as pod fragments and the like, for collection by a lower auger  26  which conveys the clean grain or seeds to an elevator, which conveys the clean grain or seeds upwardly to a clean grain bin  28 . 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 . 
     Often, chaffer  22  and sieve  24  are mounted and retained in combine  10  with hardware, such as bolts  16  and nuts  18 , as shown by a representative prior art chaffer  23  of  FIG. 2 . Retaining hardware  16 ,  18 , which is most often inserted from the side of combine  10 , must be located and removed from behind side panels on both sides of combine  10  prior to removing chaffer  23  from the rear of combine  10 . Typically chaffer  23  is lifted from its support structure (not shown), and then pulled rearwardly from combine  10 . Mounting and retaining chaffer  23  requires reversing the procedure, positioning chaffer  23  from the rear of combine  10 , pushing it into position, and lowering it on its support structure. Then retaining hardware  16 ,  18  is reinstalled on each side of combine  10 , provided bolts  16  and nuts  18  have not been lost while chaffer  23  is disassembled or removed. Also, chaffer  23  usually must be removed before gaining access to a lower sieve, which is also mounted from the sides of the combine. 
     A sieve retainer  12  according to the present invention is generally shown in  FIG. 3 . For ease of reference, the invention will be described as utilized with a chaffer, or upper sieve,  22 . It should be understood that the invention may also be utilized to retain the lower sieve  24  in a similar manner. It should also be understood that when only one side of sieve retainer  12  is shown, the opposite side operates in a similar manner to the side illustrated. As shown in  FIG. 3 , sieve  22  is supported in combine  10  by an elongate sieve support structure  30  defining a longitudinally extending elongate cavity, and includes parallel opposite side retainers  31  for supporting side edges  25  of sieve  22 . Sieve support structure  30 , along with sieve  22  are vibrated or reciprocated in a generally forward and rearward manner during a harvesting operation. Sieve retainer  12  is an end retainer structure that can be described to include a removable end portion  32  and an attached retaining portion  33 . Attached retaining portion  33  includes elongate members  36  extending rearwardly from the elongate sieve support structure  30 , and guide  50  disposed near elongate members  36 . Also, detent elements  38  are mounted and retained on elongate members  36 . Removable end portion  32  includes receiving members  34  attached to slanted support members  56  which are connected by an elongate element  48 . When utilized to retain chaffer  22 , removable end portion  32  may comprise a rake  42 , but in general, a rake would not be required for use with lower sieve  24 . 
       FIG. 4  shows one side of sieve retainer  12  in a locking configuration so as to retain sieve  22  as it may be used in a harvesting operation. Removable end portion  32  is engaged with attached retaining portion  33  at the rear of combine  10 . Elongate element  48  abuts a rear peripheral edge  54  of sieve  22  (see  FIG. 3  also) and engages guide  50 , with elongate member  36  extending through receiving member  34 . Detent  38  is positioned and oriented to abut and block rearward movement of receiving member  34  and locked in place by elements  40 . By way of example, elongate member  36  may be threaded, like an eye bolt or the like, and detent  38  may be locked in place by nuts threadedly engaged with the bolt. Other suitable retaining structure may alternatively be used. 
       FIG. 5  depicts a preferred embodiment of detent  38  and receiving member  34  according to the invention. Detent  38  includes a transverse extent A which is larger than a predetermined extent C of receiving member  34 , and a transverse extent B which is smaller than predetermined extent C of receiving member  34 . Detent  38  may also include a tab D configured to engage a notch F of receiving member  34 . When sieve retainer  12  is in the locking position, detent  38  engages receiving member  34  with larger extent A extending in the direction of extent C, and tab D engages notch F preventing rearward movement of receiving member  34 , and thus preventing rearward movement of sieve  22 . 
       FIGS. 6-8  provide some detail of the locking structure at the rear of sieve  22 .  FIG. 6  is an enlarged view of guide  50  which is near rear peripheral edge  54 . When retainer  12  is in the locked position ( FIG. 4 ), elongate element  48  is in abutting relation with rear peripheral edge  54  of sieve  22 .  FIG. 7  is a side view taken at line a-a of  FIG. 4 , showing elongate element  48  seated against rear peripheral edge  54  of sieve  22 . Finally,  FIG. 8  is a partial rear view of the structure showing the relationship between guide  50  and rear peripheral edge  54  of sieve  22 . Holding elongate element  48  against sieve  22  with such a structure allows for secure retention of sieve  22  during harvesting and easier removal for sieve replacement or maintenance. 
     Retainer  12  may be placed in an unlocking configuration to remove sieve  22  from combine  10  as shown in  FIGS. 9-12  with reference to  FIG. 5 . Locking elements  40  are loosened and moved rearwardly along elongate member  36  ( FIG. 9 ), and detent  38  is moved rearwardly away from receiving member  34  by disengaging tab D from notch F ( FIG. 10 ). Detent  38  is oriented to extend smaller transverse extent B in the direction of extent C ( FIGS. 5 and 11 ), allowing receiving member  34  to move longitudinally relative to elongate member  36  unimpeded by detent  38 . Thus removable end portion  32  may be removed from the rear of combine  10  ( FIG. 12 ), and sieve  22  may be moved longitudinally with respect to support structure  30  and removed from the rear of combine  10 . As an apparent advantage here, no small pieces of hardware need be removed from combine  10  for removal of sieve  22 . In this regard, detent  38  and locking elements  40  remain mounted on elongate member  36 , even when sieve  22  is removed. Although, any or all of these elements could be removed if desired. 
     Sieve  22 , once repaired or replaced, can be mounted on combine  10  and retained by sieve retainer  12 . Sieve  22  is slid into support structure  30  in position for a harvesting operation. Retaining sieve  22  is described with reference to  FIGS. 3-12 . In a preferred embodiment of the invention, sieve  22  may be pivoted around a line defined between side retainers  31  as indicated by the arrows shown in  FIG. 3 . When removable end portion  32  is removed from attached end portion  33 , sieve  22  may pivot downward from its position shown in  FIG. 3 , thus flattening sieve  22  for longitudinal removal. Engaging removable end portion  32  with attached retaining portion  33  may require pivoting sieve  22  up from its flattened position to abut elongate element  48  against rear peripheral edge  54  of sieve  22 . Elongate members  36  extend through receiving members  36  and detents  38  are moved and locked in place against receiving members  36 . More specifically, detents  38 , are positioned to extend transverse extents B in the direction of extents C of receiving members  34  to prevent rearward movement of receiving members  34 . Accordingly, sieve  22  will be prevented from longitudingal movement relative to support structure  30 . 
     As previously stated, the present invention can be utilized with either chaffer or upper sieve  22  or lower sieve  24 .  FIG. 13  is a simplified rear view of combine  10  with retainer  12  as described hereinabove, and including rake  42  as used with upper sieve  22 , and retainer  112  as used with lower sieve  24 . Retainers  12  and  112  are shown in their locking configurations in  FIG. 13 .  FIGS. 14 and 15  depict another advantage of the present invention.  FIG. 14  shows retainer  12  with removable end portion  32  removed allowing access to lower sieve  24  without the necessity of removing upper sieve  22 .  FIG. 15  illustrates that lower sieve  24  may be removed through aperture  114  partially defined by opposite side retainers (not shown) from the rear of combine  10  without removing upper sieve  22 . 
     It is also important to note that retainer  12  provides an additional measure of safety for operators. According to the present invention, sieves  22 ,  24  may be removed from support structure  30  of combine  10  by one longitudinal sliding movement. Presently removal requires both a lifting movement to remove sieve  22 ,  24  from support structure  30 , and then sliding movement to remove sieve  22 ,  24  from combine  10 . 
     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. Further, terms such as right/left, forward/rearward, and the like, are used for reference only. 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.