Abstract:
A locking system for attaching a threshing and/or separating element to a mounting lug on a rotor of a threshing system of an agricultural combine, including a single bolt attachment with multiple points of contact between the element and the lug created by a convex portion extending from an inner surface of the threshing and/or separating element cooperatively engaged in a recessed portion of the mounting lug. The locking system resists loading conditions generated when the crop mat engages the element, prevents radially outward movement of the threshing and/or separating element relative to the mounting lug, and reduces the stress on the mounting hardware during harvesting operations.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application Nos. 60/878,817 and 60/878,823, both filed Jan. 5, 2007. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates generally to attachment of a threshing and/or separation element to a rotor for a threshing system of an agricultural combine, and more particularly to a locking system for attaching a threshing/separating element to a mounting lug on the rotor, which locking system resists loading conditions encountered during operation, prevents radially outward movement of the element, and reduces stress on the mounting hardware of the locking system. 
       BACKGROUND ART 
       [0003]    U.S. Provisional Application Nos. 60/878,823 and 60/878,817, both filed Jan. 5, 2007, are incorporated herein in their entirety by reference. 
         [0004]    Many agricultural combines use a rotary threshing and/or separating system. The system typically includes at least one rotor drivingly rotated within a rotor housing including a perforated concave spaced radially outwardly thereof. The rotor will often have a frusto-conical inlet end having a helical flight or flights therearound for conveying a flow of crop material into a space between the rotor and the housing. The main body of the rotor will typically have an array or layout of threshing elements, such as rasp bars, and separating elements, such as straight separator bars, and the like, which protrude radially outwardly therefrom into the space for conveying a mat of the crop material along a helical path through the space, while cooperating with the concave to separate larger components of the crop, namely crop residue commonly referred to as straw, which includes stalks, stems, cobs and the like, from the smaller grain and material other than grain (MOG). 
         [0005]    The threshing/separating elements are typically attached to the rotor through the use of either hardware or the combination of hardware and a mount welded to the rotor tube. Usually a single bolt fastens each of the rasp bars and separator bars to a respective sheet metal mount welded to the rotor tube. This single bolt attachment method is known for its simplicity and ease of service. As combines have started to utilize smaller diameter rotors within the housing (sometimes referred to as “small tube” technology), the rasp bars and separator bars have become larger and the crop mat is often thicker. It has been noted, however, that operation with a thicker crop mat creates increased loading conditions, namely higher forces on the threshing/separating elements, particularly on straight separator bar type separating elements. The loading conditions generated by the interaction of the thicker crop mat with the outer surface features of the larger threshing/separating elements, create a moment at the bolt attachment to the mounting lug and urge radially outward movement of the leading edge of the elements. In some cases it has become increasingly difficult to maintain a structurally sound assembly wherein the threshing/separating elements can remain fixed to the rotor throughout various operational and crop loading scenarios. Thus, threshing/separating elements mounted to the rotor using the traditional single point attachment have been found to be inadequate in light of the increased loading conditions exerted against the threshing/separating elements, as a result of such loads as are encountered with the smaller diameter rotor constructions. 
         [0006]    Accordingly, what is sought is a locking system for attaching a threshing and/or separating element to a rotor of a threshing system of an agricultural combine which overcomes at least one of the problems, shortcomings or disadvantages set forth above. 
       SUMMARY OF THE INVENTION 
       [0007]    What is disclosed is a locking system for attaching a threshing and/or separating element to a rotor of a threshing system of an agricultural combine which overcomes at least one of the problems, shortcomings or disadvantages set forth above. 
         [0008]    According to a preferred aspect of the invention threshing elements, such as rasp bars, and/or separating elements, such as straight separator bars, and the like, are attached to mounting lugs affixed on a rotor of a threshing system using the typical single point attachment method and incorporating multiple points of contact between each element and lug to provide additional load bearing capability. The locking system is configured by incorporating a geometry that “locks” the element to the lug through physical interference between the element and the lug. Once the mounting hardware is installed, as a result of the location of the multiple points of contact and the physical interference between the element and the lug, the attachment created is very similar to a dovetail joint and a wedge style lock in strength and longevity. In particular, the multiple points of contact between the mounting lug and threshing and/or separating element are advantageous, as they prevent radially outward movement of the element relative to the mounting lug. The loading conditions, instead of being exerted at the single bolt attachment, are distributed throughout the multiple points of contact, thereby reducing the stress at the bolt and strengthening the attachment of the threshing and/or separating element to the rotor. The threshing and/or separating element is still easily removable from the mounting lug once the hardware is removed by sliding it laterally across the mounting lug, which in essence “unlocks” the element, and releases the contacting points. 
         [0009]    According to a preferred embodiment of the invention, the mounting lugs include a concave receptacle oriented to face in the direction of rotation of the rotor, with a lip or detent disposed radially outwardly of the concave receptacle and extending in the direction of rotation therefrom. Threshing and/or separating elements include a radially inwardly extending tab on the front end thereof, which tab is cooperatively received within the concave receptacle of the mounting lug for interlocking the threshing and/or separating element with the mounting lug when mounted thereon. Multiple points of contact between the tab of the element and the concave receptacle of the lug prevent radially outward movement of the forward end of the element relative to the lug, thus maintaining attachment of the threshing and/or separating elements to the rotor. 
         [0010]    As a result of the invention, the single bolt attachment method, known for its easy installation, removal, and serviceability is retained. Multiple points of contact and physical interference between the element and mounting lug are incorporated so as to better distribute loading conditions and thereby reduce stress at the single bolt attachment, and a controlled maximum deformation due to normal crop system loading is achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a side view of an agricultural combine having a threshing system including a rotor; 
           [0012]      FIG. 2  is a perspective view of a representative rotor showing a helical pattern of mounting lugs welded to the surface of the rotor; 
           [0013]      FIG. 3  is a rear perspective view of a straight separator bar according to the present invention; 
           [0014]      FIG. 4  is a rear perspective view of the straight separator bar of  FIG. 3 , shown fastened to a mounting lug according to the present invention; 
           [0015]      FIG. 5  is a sectional view of the straight separator bar of  FIG. 4  taken along line  5 - 5 ; 
           [0016]      FIG. 6  is an exploded view of the straight separator bar of  FIG. 5 ; and 
           [0017]      FIG. 7  is a sectional view of the straight separator bar of  FIG. 4  in an operational scenario, showing loading conditions exerted by a crop mat on the straight separator bar of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Turning now to the drawings,  FIG. 1  depicts a representative agricultural combine  24  including a threshing/separating system  22  having a rotor  20 . Agricultural combine  24  is representative of an axial flow type combine including one or two fore and aft extending rotors, but it should be understood that it is contemplated that the invention can likewise be used with rotors of other types of combines, including, but not limited to, conventional types wherein one or more rotors of the invention will be mounted in a transverse orientation within a body of the combine.  FIG. 2  shows a typical helical arrangement of representative prior art mounting lugs  18  affixed to rotor  20 . Threshing and/or separating elements are attached to mounting lugs  18  using a single bolt attachment, well known for its simplicity and ease of service. 
         [0019]    Referring to  FIG. 3 , wherein aspects of a preferred embodiment of a locking system  10  according to the present invention are shown, a straight separator bar  26  is shown in a rear perspective view. As one feature of the invention, a convex wedge or tab  28  extends radially inwardly from the interior of a front portion  30  of straight separator bar  26 .  FIG. 4  is a similar rear perspective view showing straight separator bar  26  fastened to mounting lug  32  and attached at a contact point by a bolt  34  according to locking system  10 . 
         [0020]      FIGS. 5 and 6  illustrate the relationship between straight separator bar  26  and mounting lug  32  in a sectional view and in an exploded sectional view taken along line  5 - 5  of  FIG. 4 . Rotor  20  is supported within combine  24  for rotation in a direction depicted by arrow  36  about a rotational axis therethrough. Mounting lug  32 , affixed to rotor  20 , includes a concave receptacle  38  facing in direction of rotation  36 . Concave receptacle  38  includes a detent in the form of a lip  40  disposed radially outwardly of concave receptacle  38  and extending in direction of rotation  36  therefrom. Concave receptacle  38  is shaped to cooperatively receive tab  28  creating additional contact between mounting lug  32  and straight separator bar  26 . Two representative locations of interest along concave receptacle  38  are denoted  42  and  44 . As can be seen in  FIG. 5 , location  42  is radially inward and rearward with respect to direction of rotation  36  when compared to location  44 . Conversely, location  44  is radially outward and forward with respect to direction of rotation  36  when compared to location  42 . As a result, lip  40  physically interferes with radially outward movement of tab  28  thereby interlocking straight separator bar  26  and mounting lug  32 . 
         [0021]    As noted above, smaller diameter rotors have given rise to larger threshing elements such as straight separator bar  26 . According to one embodiment of the invention, mounting lug  32  is modified to fasten the larger threshing elements to rotor  20 . As can be seen in  FIG. 2 , prior art mounting lug  18  has an inclined leading edge  12  facing in direction of rotation  36 , which leading edge  12  extends towards a relatively flat mounting surface  14 . Consequently, a mounting bolt (not shown) fastening a threshing element to prior art mounting lug  18  is situated generally perpendicular to the surface of rotor  20  immediately beneath the lug. In contrast,  FIGS. 5 and 6  show mounting lug  32  including concave receptacle  38  and inclined mounting surface  33  extending therefrom. Mounting bolt  34  fastening separator bar  26  is therefore preferably situated generally perpendicular to mounting surface  33  rather than rotor  20 . 
         [0022]      FIG. 7  illustrates a threshing or separating operation, and the loading conditions exerted on or near straight separator bar  26 , mounting lug  32  and bolt  34 . As a mat of crop material  56  is conveyed along a helical path through a gap or space  46  between rotor  20  and a concave  48 , crop mat  56  engages a leading edge  50  of straight separator bar  26  and is therefore compacted against an opposing surface of concave  48  as space  46  narrows near an agitation element  52 . As a result, concave  48  and straight separator bar  26  cooperate to separate smaller elements of the crop material, including grain, from larger elements, namely stalks, cobs, leaves and the like, and urge the smaller elements outwardly through apertures in concave  48 . The smaller elements, including the grain, then fall through concave  48  to a cleaning system (not shown) of combine  24  for further processing. The straw and other larger elements continue to be conveyed through space  46 , and are propelled rearwardly from the threshing/separating  22  system for disposal. 
         [0023]    Loading conditions generated by interaction of separator bar  26  with crop mat  56  in the above-explained manner, will include a range or variety of forces exerted against straight separator bar  26 , essentially distributed over the entire surface face thereof facing in direction of rotation  36 . These forces are summarized in  FIG. 7  as a force  60  exerted against agitation element  52 , and a force  66  exerted against the body of separator bar  26 , both forces being oriented in the direction opposite direction of rotation  36 . As a result mainly of force  66 , tab  28  is urged into concave receptacle  38 , as generally denoted by arrow  68 . And, as a result of the distance of agitation element  52  from the surface of rotor  20 , force  60  will act to urge separator bar  26 , and particularly leading edge  50  and tab  28 , radially outwardly (upwardly in  FIG. 7 ), as generally denoted by arrow  70 . Importantly, any radially outward movement of separator bar  26  is prevented by the points of contact between bar  26  and lip  40 , such that tab  28  is essentially forced and locked against lip  40  by force  70 . Thus, lip  40  provides physical interference preventing any radially outward movement of separator bar  26 . Lip  40  additionally provides physical interference preventing any movement of separator bar  26  in the direction opposite direction of rotation  36 , that is, any rearward movement relative to direction  36 . This serves to reduce loading conditions exerted against bolt  34 . That is, any forces exerted against bolt  34  at its interface with lug  32 , denoted generally at point  62 , such as shear forces, and moments, as denoted by arrow  64 , are reduced. Still further, as a result of inclined mounting surface  33 , forces that are exerted against bolt  34  will be at least partially compressive, as opposed to totally shear forces. 
         [0024]    While the invention has been illustrated herein with reference to straight separator bars, it should be understood that it is contemplated that the locking system of the invention can likewise be used with any threshing and/or separating elements, including rasp bars, straight separator bars and the like. Accordingly, locking system  10  of the present invention preserves the traditional single bolt attachment known for its simplicity and serviceability, and overcomes the undesirable stress at the single bolt attachment by providing physical interference at additional points of contact between the threshing and/or separating element and mounting lug. 
         [0025]    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.