Abstract:
An improved knife assembly for use with a header of an agricultural harvester. The assembly includes a knife head, a knife back and a plurality of sickle sections fastened to the knife head and knife back. The sickle sections include first and second portions where a second portion of one knife section overlaps a first portion of an another sickle section when the knife sections are arranged in adjacent relationship. The overlapping areas of the adjacent knife sections include aligned though holes which shared fasteners. The resultant construction reduces the overall knife assembly mass thereby leading to increased cutting speeds and corresponding harvester ground speeds. Additionally, the time and labor associated with manufacture and maintenance is reduced while the assembly strength and force distribution capability is enhanced.

Description:
BACKGROUND 
       [0001]    The subject application relates generally to headers for agricultural harvesters. In particular, the subject application relates to a header including an improved cutting knife assembly having overlapping sickle sections. 
         [0002]    Agricultural harvesters such as combine harvesters are well known apparatuses for harvesting grain crops. An agricultural harvester is typically a self-propelled vehicle which includes a feederhouse and mechanisms downstream of the feederhouse for separating grain from other crop material. A header is attached to the front of the harvester and includes mechanisms for cutting crop, gathering crop and delivering crop to the harvester&#39;s feederhouse. A typical crop cutter includes a stationary knife and a reciprocating knife which together act as shears that cut crop near the ground. After cutting, the crop is gathered e.g., by a harvesting reel which feeds the cut crop to a conveyor system that transports the cut crop to the harvester&#39;s feederhouse. 
         [0003]    Typical reciprocating knife assemblies include knife blades formed from a plurality of sickle sections which are bolted to a knife back, some of which are also bolted to a knife head. In the event a sickle section becomes dulled or damaged and requires replacement, the affected section is unbolted and replaced by a new section. However, such repair can be time consuming and labor intensive, especially if several sickle sections require replacement. This is because conventional sickle sections each require two or more fasteners to secure the sickle sections to the underlying knife back and possibly the knife head. 
         [0004]    Still further, the many fasteners required to secure the sickle sections to the knife back and knife head add an undesirable number of components and additional mass to the assembly. This is problematic in the sense that the more massive the knife assembly the more energy is required to propel the reciprocating blade in one direction then stop the blade and propel it in the opposite direction. Consequently, excessive mass combined with changes in velocity (acceleration/deceleration cycles) at each end of the knife stroke detrimentally affects knife speed which, in turn, introduces vibration and can result in slower cutting, slower combine ground speed and less than optimal harvesting productivity, while the increased number of components adds to manufacturing and maintenance complexity. 
       BRIEF SUMMARY 
       [0005]    In accordance with a first aspect, the subject application provides a sickle knife assembly for use with a header of an agricultural harvester. The assembly addresses the problems of lengthy repair time and unnecessary apparatus mass by virtue of a robust yet simple construction. The subject application is directed to a knife or sickle assembly that uses overlapping sickle sections to reduce the number of fasteners required to assemble and repair the apparatus. Such reduction in the number of fasteners translates to faster repair time in that fewer fasteners need to be removed and replaced during a maintenance procedure. The considerable reduction in the number of fasteners also reduces the overall mass of the knife assembly. As a result, the knife assembly may cut crop at higher speeds and the harvester may be driven at correspondingly higher ground speeds thereby increasing harvesting efficiency and productivity. 
         [0006]    In accordance with a second aspect, the subject application provides a sickle section for use in a knife assembly having a plurality of sickle sections disposed in adjacent relationship. The sickle section includes a first portion lying in a first plane, and a second portion lying in a second plane spaced from the first plane and connected to the first portion. The first portion includes a crop cutting region and a knife back attachment region distal from the crop cutting region. The second portion overlaps with an adjacently positioned sickle section. 
         [0007]    In accordance with a third aspect, the subject application provides a knife assembly for use with a header of an agricultural harvester. The knife assembly includes a knife back and first and second sickle sections mounted on the knife back. Each of the first and second sickle sections includes a first portion lying in a first plane, and a second portion lying in a second plane spaced from the first plane and connected to the first portion. The first portion includes a crop cutting region and a knife back attachment region distal from the crop cutting region. The first sickle section is mounted on the knife back adjacent the second sickle section and the second portion of the first sickle section overlaps the second sickle section. 
         [0008]    In accordance with a fourth aspect, the subject application provides a knife assembly for use with a header of an agricultural harvester. The knife assembly includes an elongated knife back and first and second sickle sections adjacently mounted on the knife back. The first and second sickle sections include a first portion lying in a first plane. The first sickle section further includes a second portion lying in a second plane spaced from the first plane and connected to the first portion. The first portion of the first sickle section includes a crop cutting region and a knife back attachment region for attaching the first sickle section to the elongated knife back. The first portion of the second sickle section includes a crop cutting region and a knife back attachment region for attaching the second sickle section to the elongated knife back. When mounted to the knife back, the second portion of the first sickle section overlaps a portion of the knife back attachment region of the second sickle section. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]    The foregoing summary, as well as the following detailed description of several aspects of the subject application, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the subject application there are shown in the drawings several aspects, but it should be understood that the subject application is not limited to the precise arrangements and instrumentalities shown. 
           [0010]    In the drawings: 
           [0011]      FIG. 1  is front elevation view of a conventional agricultural harvester including a header; 
           [0012]      FIG. 2  is a top plan view of a conventional knife assembly for use in the header of  FIG. 1 ; 
           [0013]      FIG. 3  is a front elevation view of the knife assembly of  FIG. 2 ; 
           [0014]      FIG. 4  is an exploded view of the knife assembly of  FIG. 2 ; 
           [0015]      FIG. 5  is an enlarged top plan view of a conventional sickle section for use in the knife assembly of  FIGS. 2-4 ; 
           [0016]      FIG. 6  is an enlarged perspective view of a knife head of the knife assembly of  FIGS. 2-4 ; 
           [0017]      FIG. 7  is an exploded perspective view of a knife assembly according to an aspect of the subject application; 
           [0018]      FIG. 8  is an assembled perspective view of the knife assembly of  FIG. 7 ; 
           [0019]      FIG. 9  is an enlarged perspective view of a sickle section of the knife assembly of  FIG. 7 ; 
           [0020]      FIG. 10  is a partial side elevation view of several sickle sections of the knife assembly of  FIG. 7 ; and 
           [0021]      FIG. 11  is an enlarged perspective view of a knife head of the knife assembly of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Reference will now be made in detail to the various aspects of the subject application illustrated in the accompanying drawings. Wherever possible, the same or like reference numbers will be used throughout the drawings to refer to the same or like features. It should be noted that the drawings are in simplified form and are not drawn to precise scale. In reference to the disclosure herein, for purposes of convenience and clarity only, directional terms such as top, bottom, left, right, above, below and diagonal, are used with respect to the accompanying drawings. Such directional terms used in conjunction with the following description of the drawings should not be construed to limit the scope of the subject application in any manner not explicitly set forth. Additionally, the term “a,” as used in the specification, means “at least one.” The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import. 
         [0023]    Referring now to the drawings, wherein aspects of the subject application are shown,  FIG. 1  illustrates an agricultural harvester  10  such as a combine. Harvester  10  includes a header  12  which is attached to a forward end  14  of the harvester and which is configured to cut crops and to induct the cut crops into a feederhouse  16  as harvester  10  moves forward over a crop field. 
         [0024]    Header  12  includes a floor  18  that is supported in desired proximity to the surface of a crop field and an elongate sickle assembly  20  that extends transversely along a forward edge of the floor  18 . Sickle assembly  20  is configured to cut crops in preparation for induction into the feederhouse  16 . Additionally, header  12  includes an elongate, transversely extending harvesting reel  22  disposed above sickle  20 . Harvesting reel  22  is rotatable in a direction suitable for facilitating the induction of cut crops into feederhouse  16 . Header  12  further includes an elongate, rotatable auger  24  which extends in close proximity to a top surface  26  of floor  18 . Auger  24  is configured to cooperate with harvesting reel  22  in conveying cut crops to feederhouse  16 , which is configured to convey the cut crops into harvester  10  for threshing and cleaning. While the foregoing aspect of the subject application is being described with respect to a draper header, the knife assembly of the subject application can be applied to any other header having use for a knife assembly or sickle section. 
         [0025]    Sickle assembly  20  extends along a forward edge  28  of floor  18 , and generally is bounded by a first side edge  30  and an opposing second side edge  32  of floor  18 . Sickle assembly  20  can be configured to include a first reciprocating knife assembly  34  and a second reciprocating knife assembly  36  (along with an unillustrated stationary knife). The reciprocating mechanisms of such knife assemblies are known in the art and a further detailed description of their structure, function and operation is not necessary for a complete understanding of the subject application. However, a typical reciprocating mechanism applicable to the knife assembly of the subject application is disclosed in U.S. Pat. No. 8,151,547, the entire disclosure of which is incorporated by reference herein. The structural details of knife assembly  34  are illustrated in greater detail in conjunction with  FIGS. 2-6  and it will be understood that knife assembly  36  is structurally similar or identical to knife assembly  34 . 
         [0026]    Referring to  FIGS. 2-4  and  6 , it will be seen that knife assembly  34  includes a knife head  38  (shown enlarged in  FIG. 6 ), a knife back  40  and a plurality of sickle sections  42  connected to the knife back. A series of sickle sections is also disposed between the knife head and knife back. As is known, a proximal end of the knife head  38  is attached to a reciprocating driver element  44  which in turn is driven by an unillustrated motor which imparts reciprocating motion to the knife assembly  34 . A plurality of fasteners such as bolts  46  ( FIGS. 3 and 4 ) and nuts  48  ( FIGS. 2-4 ) unite the knife head  38 , knife back  40  and sickle sections  42 . More particularly, the knife head  38 , knife back  40  and sickle sections  42  have aligned through holes  38   a ,  40   a  and  42   a , through which bolts  46  pass to threadedly engage with nuts  48 . 
         [0027]    As seen in  FIGS. 2-4 , knife head  38  does not extend the entire length of knife back  40  since the knife head need only span several but not all of the sickle sections  42  in order to impart structural rigidity to the knife assembly  34 . However, in order to assure secure attachment of the sickle sections  42  to the knife back  40  in regions beyond the reach of knife head  38 , it is common for a typical cutting head assembly to include spanner plates  50  which bridge the upper surfaces of adjacent sickle sections  42 . The spanner plates  50  are secured to the sickle sections and underlying knife back by bolts and nuts  46 ,  48 . 
         [0028]    Referring to  FIG. 5  there is shown on an enlarged scale a conventional sickle section  42 . As seen in  FIG. 5 , sickle section  42  includes a crop cutting region  52  and a knife back attachment region  54 . Crop cutting region  52  is generally triangular in shape and includes serrated edges  56  while knife back attachment region  54  includes a pair of through holes  42   a  through which bolts  46  pass to secure the sickle section to the knife back  40  as well as the knife head  38 . The sickle section  42  is also configured as a planar element with the crop cutting region and knife back attachment region lying on the same plane. Moreover, when assembled to the knife back  40 , each sickle section  42  lays in side by side relation to each other all along a single plane parallel to the plane of the knife back  40 . 
         [0029]      FIGS. 7-11  depict aspects of a knife assembly according to the subject application. The knife assembly  134  is adapted for use with a header of an agricultural harvester and includes a plurality of sickle sections constructed as described below. 
         [0030]    Turning first to  FIGS. 7 and 8 , there is shown in exploded and assembled view, respectively, a knife assembly  134  in accordance with the subject application. The knife assembly  134  includes a knife head  138  (shown enlarged in  FIG. 11 ), a knife back  140  and a plurality of sickle sections  142  (shown enlarged in  FIG. 9 ) that attach to the knife back. Knife back  140  is an elongated member configured with a plurality of spaced apart through holes  140   a . Similarly, knife head  138  is also somewhat elongated and includes a plurality of spaced apart through holes  138   a . As described below, the knife head  138 , knife back  140  and sickle sections  142  can be united by plugs or other fasteners such as nuts and bolts in a manner similar to that described above in connection with cutting knife assembly  34 . 
         [0031]    Referring to  FIG. 9  there is shown on an enlarged scale a sickle section  142  constructed according to an aspect of the subject application. Sickle section  142  can be die or laser cut, forged or machined and includes a first portion  158  lying in a first plane. The first portion  158  includes a crop cutting region  152  and a knife back attachment region  154  distal from the crop cutting region. Sickle section  142  further includes a second portion or tongue  160  connected to the first portion  158  and lying in a second plane spaced from the first plane. The second portion  160  is connected to the knife back attachment region  154  of the first portion  158  and is adjacent to the knife back attachment region and distal from the crop cutting region  152 . 
         [0032]    The second portion  160  is configured to overlap with an adjacently positioned sickle section in a manner described below. According to an aspect of the subject application, the second plane of the second portion  160  is spaced from and substantially parallel to the first plane of the first portion  158 . The offset of the second portion  160  relative to the first portion  158  or the offset of the first plane from the second plane is equal or substantially equal to a thickness of the first portion. 
         [0033]    For example, the second portion  160  is connected to the first portion  158  in a stair-like fashion or configuration. The stair-like structure of the first and second portions  158 ,  160  have a rise that is equal to a planar thickness of an individual sickle section e.g., the flight of the step defined by the first and second portions  158 ,  160  can be deemed to have a thickness of an individual sickle section. The stair structure of the first and second portions  158 ,  160  is best shown in  FIG. 10 . 
         [0034]    The knife back attachment region  154  includes a first fastening portion  142   a  and the second portion  160  includes a second fastening portion  160   a  for a cooperative fastening application as described below. The first fastening portion  142   a  can be a first through hole  142   a  and the second fastening portion  160   a  can be a second through hole  160   a.    
         [0035]    Referring to  FIGS. 7 ,  8  and  10 , a plurality of sickle sections  142  are shown arranged in adjacent relationship. As most clearly seen in  FIG. 10 , when a plurality of sickle sections  142  are assembled and arranged in adjacent relationship, the second portion  160  of one sickle section overlaps the first portion  158  of an adjacent sickle section. Specifically the second portion  160  overlaps with the knife back attachment region  154  of the first portion. Further, the second through hole  160   a  of one sickle section aligns with the first through hole  142   a  of an adjacent sickle section. The aligned pair of the first and second through holes  142   a ,  160   a  is operable to share and receive a plug or other fastener such as a bolt  146  and a nut  148 . Such a fastener is also shared with a through hole  140   a  of knife back  140  when the sickle sections are fastened to the knife back. Upon securing the fastener, the second portion  160  of a first sickle section is connected to the knife back attachment region  154  of an adjacent second sickle section. Thus, between adjacent first and second sickle sections, the knife back attachment region  154  of the second sickle section having a first fastening portion and the second portion  160  of the first sickle section having a second fastening portion form a cooperative fastening application for assembling the first and second sickle sections together. 
         [0036]    As most clearly illustrated in  FIG. 10 , the knife assembly  134  defines an arrangement where adjacent sickle sections  142  are connected in chain-like fashion, e.g., a single fastener is used to secure two adjacent sickle sections to the knife back  140 . Hence, the number of fasteners corresponds to the number of links in essentially a one-to-one relationship. This construction is quite unlike conventional designs where at least two fasteners are required to secure each sickle section to the knife back. The practical significance of the subject arrangement is that fewer fasteners are required to secure the sickle sections to the knife back, thereby resulting in a lower number of components, less overall knife assembly mass, and less time and labor required to assemble the apparatus as well as replace worn or damaged sickle sections. Moreover, the interconnected “chain” arrangement of the sickle sections  142  serves to effectively distribute transverse loads, i.e., loads that occur along the longitudinal axis of the knife back  140 , among adjacent sickle sections. Additionally, the interconnected chain arrangement in combination with the sickle section second portion provides improved longitudinal stiffness or resistance to vertical flexure, therefore allowing for a less massive knife back than that which is presently employed in comparably sized knife assemblies. 
         [0037]    Referring to  FIG. 11 , there is shown the construction of the knife head  138 . The knife head  138  includes a plurality of through holes  138   a  arranged for cooperative fastening alignment with the through holes of the sickle sections and the through holes of the knife back. Knife head  138  further includes a plurality of spaced apart recesses  164  on its underside for accommodating the second portions of sickle sections at locations where a second portion of one sickle section overlaps a first portion of an adjacent sickle section. So constructed, the knife head  138  closely follows the contours of the upper surfaces of the sickle sections in order to provide continuous and firm contact therewith in regions where the knife head, sickle sections and knife back are united. By closely following the contours of the upper surfaces of the sickle sections, the knife head provides a high degree of contact area between itself and the sickle sections which results in rigid and stiff knife assembly. 
         [0038]    Referring back to  FIG. 9 , a notch  162  is provided at a juncture of the first and second portions  158 ,  160  of sickle section  142  and proximate the connection of the second portion to the first portion. Notch  162  is a stress relieving feature that also allows for increased flexibility of the second portion relative to the first portion. Further, the end opposite the notch end of the knife back attachment region  154  of sickle section  142  can be provided with a recessed area  164 . Such recessed area is operable to accommodate a transition region  166  located between the first and second portions  158 ,  160  of an adjacent sickle section when the sickle sections are arranged in side by side relationship. The transition region  166  thus functions as a key that is matingly received in recessed area  164 . The cooperating key and recess arrangement functions as a guide for aiding in assembly of the knife assembly while simultaneously adding strength to the overall knife assembly. 
         [0039]    According to the subject application, the sickle sections  142  and resultant knife assembly  134  incorporating such sickle sections produces a robust yet comparatively less massive and more easily and quickly assembled and maintained assembly than heretofore known in the art. For example, the overlapping sickle sections require fewer fasteners than presently available sickle sections, thereby resulting in less time and labor to assemble at manufacture as well as when replacing worn or damaged sections. Additionally, the reduced number of fasteners results in lower overall assembly mass which in turn leads to higher cutter reciprocation speed, higher harvester ground speed and improved harvesting efficiency and productivity. Further, the chain-like overlapping nature of the sickle sections distributes transverse loads more effectively than conventional arrangements where adjacent sickle sections lie in simple abutting relationship. Furthermore, owing to its design the interconnected sickle sections are longitudinally stiffer than conventional side-by-side sickle section designs. Accordingly, in relation to comparable existing designs, a less massive knife back is required to achieve the same sickle section support capability. Still further, by virtue of its continuous contact with the contours of the overlapping sickle sections, the improved knife head design disclosed herein provides for improved overall assembly. 
         [0040]    It will be appreciated by those skilled in the art that changes could be made to the aspects described above without departing from the broad inventive concept thereof. It is to be understood, therefore, that the subject application is not limited to the particular aspects disclosed, but it is intended to cover modifications within the spirit and scope of the subject application as defined by the appended claims.