Abstract:
A wear shield is attached to a cutter bar and is formed from a molded wear body having a front mounting portion bolted onto the guards of the cutter bar by the guard mounting bolts with recesses for the guard fingers and a front edge of an upper planar mounting surface clamped onto the guard bar. A rear covering portion is cantilevered rearwardly from the front mounting portion underlying a bottom plate of the cutter bar for engaging the ground so as to underlie and protect the bottom plate. Resilience in the wear shield forces the rear part against the bottom plate of the cutter bar to avoid the necessity for a rear fastener. A series of the wear shields is arranged side by side across the cutter bar with two side edges each for locating adjacent a side edge of a next adjacent wear shield.

Description:
[0001]     This invention relates to a wear shield for the cutter bar of a crop harvesting machine where the cutter bar includes a guard bar mounted on a front edge of the cutter bar, a plurality of cutter guards carried on mounting bolts at spaced positions along the guard bar and a ground engaging bottom plate on the cutter bar extending rearwardly from the guard bar.  
       BACKGROUND OF THE INVENTION  
       [0002]     The above type of cutter bar is well known and widely used in crop harvesting machines of the sickle knife type in which a knife is carried on the guards and reciprocates across the guards in a cutting action.  
         [0003]     For some crops, the cutter bar is carried so that it skids over the ground with much of the weight of the header carried on springs but a small amount of the weight applied through the cutter bar onto the ground to hold the cutter bar against the ground in a skidding action to provide the cutting action at the lowest possible position relative to the ground.  
         [0004]     It is well known that wear shields are mounted on the cutter bar at the position where the cutter bar contacts the ground so as to reduce the frictional wear on the cutter bar itself and to apply it instead to a replaceable plastic wear piece which can be removed when worn and replaced by a new wear piece.  
         [0005]     Commonly such shields are bolted onto the bottom plate of the cutter bar simply by bolting through the shield into the bottom plate behind the guard bar of the cutter bar.  
         [0006]     Examples are shown in U.S. Pat. No. 5,924,270 (Bruns) assigned to May-Wes Manufacturing Inc. and issued Jul. 20, 1999, U.S. Pat. No. 5,174,101 (Rabitsch) issued Dec. 29, 1992 and Design patent D454,576 (Huntimer) assigned to Global Polymer Industries Inc. and issued Mar. 19, 2002. All these patents show basically the same arrangement in which a sheet of plastic material is simply bolted to the underside of the bottom plate by front and rear fasteners.  
       SUMMARY OF THE INVENTION  
       [0007]     It is one object of the invention to provide an improved wear shield of this type.  
         [0008]     According to one aspect of the invention there is provided a wear shield for attachment to a header of a crop cutting machine having a cutter bar, a guard bar mounted on a front edge of the cutter bar, a plurality of cutter guards carried on mounting bolts at spaced positions along the guard bar and a ground engaging bottom plate on the cutter bar extending rearwardly from the guard bar;  
         [0009]     the wear shield comprising:  
         [0010]     a molded wear body having a front mounting portion and a rear covering portion;  
         [0011]     the front mounting portion having at least one mounting hole arranged to engage a mounting bolt of a respective one of the guards;  
         [0012]     the rear covering portion being arranged to extend rearwardly from the front mounting portion and having a bottom surface arranged for engaging the ground so as to underlie and protect the bottom plate;  
         [0013]     the front mounting portion and the rear covering portion having two side edges each for locating alongside a next adjacent wear shield so that the wear shields can be arranged side by side across the cutter bar.  
         [0014]     The wear shield may be arranged to be mounted on a single cutter guard or may be longer so as to bridge a number of such guards. The single mounting allows easier removal and mounting simply by removing the guard bolts.  
         [0015]     Preferably the front mounting portion has at least one recess therein arranged to receive a portion of a respective one of the guards therein. This may be provided by two such recesses side by side for the double fingers of the common guard arrangement, but a single recess may also be used.  
         [0016]     Preferably the front mounting portion has upper surface portions arranged to lie in a common plane so as in use to butt against a bottom surface of the guard bar.  
         [0017]     Preferably the wear shield is resilient and a part or parts are arranged as interference fit with the cutter bar such that when bolted onto the guard bar at least a rear edge of the upper surface portion is pressed by its own resilience causing spring loading against the bottom plate of the guard bar to avoid flapping and to reduce the possibility of entry therebetween of soil. This avoids the necessity for a rear fastener or clip.  
         [0018]     Preferably the front mounting portion has at least one recess therein arranged to receive a portion of a respective one of the guards therein and wherein the recess has a bottom surface portion arranged to butt against a bottom surface of the portion of the respective one of the guards.  
         [0019]     Preferably the front mounting portion has two recesses therein each arranged for receiving a respective one of two guard fingers of the respective one of the guards, two side pieces each extending outwardly to a respective side of a respective one of the recesses and a center piece between the two recesses, wherein the center piece includes a front recess section extending thereacross for receiving a center bar of the guard.  
         [0020]     Preferably the rear covering portion is cantilevered from the front mounting portion so that the molded wear body is only supported at the front mounting portion by the mounting bolt.  
         [0021]     Preferably the rear covering portion includes an upper surface for engaging the bottom plate and wherein the upper surface includes a plurality of upwardly extending ribs defining an upper surface of the ribs for engaging the cutter bar rearwardly of the guard bar.  
         [0022]     Preferably the front mounting portion has a front edge arranged to extend along a front edge of the guard bar substantially coincident therewith.  
         [0023]     Preferably the mounting bolt includes a first shoulder for engaging a bottom surface of the cutter guard and a second shoulder axially spaced from the first for engaging a bottom surface of the wear shield.  
         [0024]     According to a second aspect of the invention there is provided a wear shield comprising:  
         [0025]     a molded wear body having a front mounting portion and a rear covering portion;  
         [0026]     the front mounting portion having at least one mounting hole;  
         [0027]     the rear covering portion being arranged to extend rearwardly from the front mounting portion and having a bottom surface arranged for engaging the ground;  
         [0028]     the front mounting portion and the rear covering portion having two side edges each for locating alongside a side edge of a next adjacent wear shield so that the wear shields can be arranged side by side across the cutter bar;  
         [0029]     wherein the front mounting portion has at least one recess therein arranged to receive a portion of a respective one of the guards therein; and  
         [0030]     wherein the front mounting portion has upper surface portions arranged to lie in a common plane for engaging a bottom surface of the guard bar.  
         [0031]     According to a third aspect of the invention there is provided a cutter apparatus of a crop cutting machine comprising:  
         [0032]     a cutter bar,  
         [0033]     a guard bar mounted on a front edge of the cutter bar,  
         [0034]     a plurality of cutter guards carried on mounting bolts at spaced positions along the guard bar;  
         [0035]     a ground engaging bottom plate on the cutter bar extending rearwardly from the guard bar;  
         [0036]     and a wear shield for covering the bottom plate comprising:  
         [0037]     a molded wear body having a front mounting portion and a rear covering portion;  
         [0038]     the front mounting portion having at least one mounting hole engaging a mounting bolt of a respective one of the guards;  
         [0039]     the rear covering portion being arranged to extend rearwardly from the front mounting portion and having a bottom surface for engaging the ground so as to underlie and protect the bottom plate;  
         [0040]     the front mounting portion and the rear covering portion having two side edges each for locating alongside a side edge of a next adjacent wear shield so that the wear shields can be arranged side by side across the cutter bar. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0041]     One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:  
         [0042]      FIG. 1  is an isometric view from the underside showing the cutter bar, guard bar and one guard of a crop harvesting machine together with one wear shield of a series of such wear shields according to the present invention.  
         [0043]      FIG. 2  is an isometric view from the top and one side of the wear shield only of  FIG. 1 .  
         [0044]      FIG. 3  is an isometric view from the top and rear of the wear shield of  FIG. 1 .  
         [0045]      FIG. 4  is an end elevational view of the components of  FIG. 1  including the wear shield.  
         [0046]      FIG. 5  is a cross sectional view along the lines  5 - 5  of  FIG. 4 .  
         [0047]      FIG. 6  is a cross sectional view along the lines  6 - 6  of  FIG. 5 .  
         [0048]      FIG. 7  is a cross sectional view along the lines  7 - 7  of  FIG. 5 .  
         [0049]      FIG. 8  is a cross sectional view along the lines  8 - 8  of  FIG. 5 . 
     
    
       [0050]     In the drawings like characters of reference indicate corresponding parts in the different figures.  
       DETAILED DESCRIPTION  
       [0051]     A cutter bar is generally indicated at  10  for use with a crop cutting machine. The cutter bar itself is of a generally conventional construction including a generally C-shaped cutter bar  11  with a front edge  12  at which is mounted a guard bar  13 . The guard bar defines a flange welded at the rear edge  14  to the front surface  12  and defining a front edge  15  and a top surface  16 . A series of mounting holes  17  are formed through the guard bar for mounting at spaced positions along the length of the bar a plurality of guards  17 .  
         [0052]     Again the guards  17  are of a conventional construction including a pair of guard fingers  18  and  19  each of which defines a slot  20  through which the sickle knife passes, the sickle knife including a knife bar which is carried on a support surface  21  of the guard extending across between the two fingers and extending outwardly to each side to a side edge  22  of the bar.  
         [0053]     At the rear of the fingers, each finger is mounted underneath the guard bar  13  so as to be bolted to a bottom surface  24  of the guard bar  13 . Thus the rear end of each finger, as best shown in  FIG. 6 , includes a rearwardly projecting portion  25  which underlies the bottom surface  24  of the guard bar. The portion  25  has a width which is the same or basically the same as the width of the finger itself so that the portion  25  extends only under a part of the length of the guard bar with the remainder of the bottom surface  24  of the guard bar being exposed.  
         [0054]     The portion  25  is clamped to the bottom surface  24  of the guard bar by a series of mounting bolts  26  each of which carries a nut  27  contacting the top surface  16 . A head  28  on the underside has a shoulder  29  engaging the bottom surface of the portion  25  to vigorously clamp the guard finger up underneath the guard bar  13 .  
         [0055]     The cutter bar  11  includes a bottom plate  30  which extends downwardly and rearwardly from the front portion  12  to a rear edge  31 . The bottom plate  30  thus is arranged below the guard bar  13  so that it contacts the ground and, when contacting the ground, supports the guards above the ground to carry the sickle knife above the ground in a cutting action.  
         [0056]     A series of wear shields  40  are arranged side by side across the cutter bar so as to provide a wear surface underneath the portions  25 , underneath the guard bar  13  and underneath the bottom plate  30 .  
         [0057]     The wear shields  40  in the embodiment shown are arranged so that they have a width generally equal to the width of an associated guard. However wear shields of a greater width can be manufactured so as to co-operate with a series of the guards. The single shield for each guard is selected for easier mounting since the wear shield can be removed and replaced simply by removing and replacing the associated one of the guards. Each wear shield  40  has a front mounting portion  41  and a rear covering portion  42 . The front mounting portion  41  is arranged to be mounted at the guard plate. The rear covering portion extends rearwardly from a front edge  43  of the rear covering portion rearwardly and downwardly over the bottom plate  30  to a rear edge  44  of the rear covering portion. The rear covering portion  42  has an upper surface  45  generally shaped to follow the shape of the undersurface of the bottom plate  30 . The surface  45  includes a flat rear portion  45 A and a forward portion  45 B. At the forward portion  45 B is located a plurality of ribs  46  including five longitudinal ribs and two transverse ribs  47  and  48 . The ribs thus define recesses  49  between the ribs. The wear shield is formed by moulding so that the presence of the recesses  49  reduces the quantity of material in the molding process so that the thickness of the wear shield excluding the ribs is substantially constant to provide a substantially constant wear thickness throughout the rear portion  42 . The ribs however have an upper planar surface for butting against the outside surface of the plate  30  to hold the bottom surface of the wear shield indicated at  50  as a generally smooth surface extending from the underside of the guard bar  13  rearwardly to the rear edge  31  of the bottom plate.  
         [0058]     The front mounting portion  41  includes a center mounting section  52 , a first recess  53 , a second recess  54  and two side mounting portions  55  and  56 . The recesses  53  and  54  are shaped and arranged to receive the portions  25  of the guard underlying the bottom surface  24  of the guard bar. Thus the recesses extend into the body of the moulded structure forming the wear shield to a surface  57  at the bottom of the recess which is shaped and arranged to butt against the bottom surface of the portion  25  of the guard.  
         [0059]     At the bottom of the recesses  53  and  54  is formed a hole  58  through which the shoulder  29  of the bolt  28  projects so that the shoulder  29  can butt against the bottom surface of the portion  25  without engaging the front portion  41  of the wear shield  40 .  
         [0060]     From a review of  FIGS. 5 and 6 , it will be noted that the head  28  of the bolt  26  includes a second shoulder  59  outside the shoulder  29  and below the shoulder  29  which butts against the shoulder  60  of a recess  61  in the front portion  41 . Thus the double shoulder  29 ,  59  of the bolt  26  acts to hold both the bottom surface of the portion  25  against the guard bar  13  and also acts to hold the bottom portion of the front portion  41  against the underside of the portion  25  of the guard.  
         [0061]     The center portion  52  and the side mounting portions  55  and  56  each define a butting surface  62 ,  63  and  64  for contacting the bottom surface  24  of the guard bar  13 . These surfaces are coplanar so as to contact the planar surface  24 .  
         [0062]     The side mounting portions  55  and  56  each include a front edge of the respective surface indicated at  62 A and  64 A respectively. These edges  62 A and  64 A are arranged so as to be substantially coincident with the front face  15  of the guard bar  13 . Thus as best shown in  FIG. 8 , the bottom surface of the front portion  41  of the wear shield curves forwardly and upwardly to the front edge  64 A which meets the front edge  15  of the guard bar  13 .  
         [0063]     The moulding of the plastic material forming the wear shield is arranged so as to provide an interference fit of the edge  64 A so that it is slightly larger than required and thus is slightly distorted by compression from the underside  24  of the guard bar  13  when the front portion  41  is clamped into place by the bolts  26 . This provides a tight edge across the front of the wear shield and locates this front edge at the front edge of the guard bar so as to provide a generally smooth surface from the front edge of the guard bar rearwardly for contacting the ground and preventing the penetration and collection of soil from the ground.  
         [0064]     As best shown in the cross section of  FIG. 7 , the guard  17  includes a cross bar  17 A connecting the fingers rearwardly of the knife support bar  21 . This provides an upper surface  17 B which also provides support for the knife bar. The cross bar  17 A includes a front portion  17 C in front of the front edge  15  of the guard bar  13  and a rear portion  17 D which extends downwardly and rearwardly to contact against the bottom surface  24  of the guard bar  13 . Thus the cross bar  17 A forms part of the clamping arrangement by which the guard is clamped underneath the guard bar. Thus the upper surface of the cross bar  17 A at the portion  17 D is coplanar with the top surface of the portion  25  at the rear of the respective guard finger.  
         [0065]     The center mounting portion  52  has the coplanar surface  63  arranged to contact the underside of the guard bar. However the center portion is recessed as indicated at  66  across the front edge of the wear shield to receive the portion  17 D of the cross bar  17 A. Thus the center mounting portion  52  has a front edge  63 A which is recessed from the surface  63  and butts against the bottom surface of the portion  17 D of the cross bar  17 A. A shoulder  67  of the recess  66  butts against a rear surface of the cross bar  17 A.  
         [0066]     The front portion is thus moulded so that it has sections underlying the guard at the rear part of the guard. Thus the front edge  63 A in the center mounting section butts up against the underside of the cross bar  17 A. Thus each of the recesses  53  and  54  has a front edge  53 A,  54 A which butts against the underside of the portion  25  of the respective finger. In this way the front edge of the front portion  41  provides a smooth edge butting against the underside of the guard with no spaces between the guard and the front edge of the wear shield thus preventing the penetration of soil or any possibility for obstacles entering into this area and ripping the wear shield from its mounted position.  
         [0067]     The advantages of the arrangement described above are as follows:  
         [0068]     1 The profile of the bottom surface of the wear shield promotes soil flow and eliminates soil build-up and friction, specifically where it mounts to the guard at the front edges which are clamped to the guard.  
         [0069]     2. The wear shield is molded to follow the guard shape so that portions of the wear shield are located underneath the rear portion  25  of the fingers.  
         [0070]     3. The wear shield is held in place only by the two guard bolts without any additional steel plates or other elements which must be removed or could wear. The wear shield is therefore easily and quickly removed simply by removing the guard bolts.  
         [0071]     4. There is about 7 millimetres of interference between the wear shield and the bottom plate of the cutter bar which creates a tight fit at the junction between the wear shield and the bottom plate. This is achieved by the contact at the front between the front edge of the wear shield and the guard bar and the lifting effect of the bolt which pulls the rear edge of the wear shield upwardly against the bottom plate. The resilience of the wear shield provide a spring force loading the rear part of the wear shield against the bottom plate of the cutter bar.  
         [0072]     The arrangement as shown provides only a single wear shield for each guard but it will be appreciated that the wear shield could be made in widths for multiple guards.  
         [0073]     The guard bolts  26  are of a special design which has the double shoulder arrangement for clamping both the guard and the wear shield. The bolts have a longer square neck and additional round head.  
         [0074]     Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without departure from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.