Patent Abstract:
An improved mounting arrangement for a knife to a disc for use on a rotary disc cutter that eliminates the need for a threaded connector and the associated nut is disclosed. It also provides a positive retention method on the top side of the disc. In addition, it provides a method of removing the knife from the disc without the use of wrenches, simply requiring a tool for prying, such as a screw driver. A further feature is a low profile retainer does not need to be protected by a wear protector.

Full Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     FIELD OF THE INVENTION 
     The present invention relates to a pivotal mounting arrangement for mounting a knife to a rotary disc, which makes replacement, or reorientation of the blade possible using only common tools. 
     BACKGROUND OF THE INVENTION 
     Knives used on rotary disc mowers contact the crop material at high speeds, in order to cut effectively. This results in inherent dulling and wear. At times these knives contact other objects such as the ground, rocks etc. causing additional wear. As a result the knives must routinely be maintained. 
     The knives are pivotally mounted to discs, in a manner to reduce impact loading on the sharpened edge when striking an obstacle. FIGS. 1-4 illustrate a prior art mounting arrangement. Mower disc assembly  10  includes knife adapter  30  that is attached to the bottom side of disc body  20 , retained with bolt  15  which passes through aperture  26  of disc  20  and into threaded aperture  36  of knife adapter  30 . The knife adapter  30  can alternatively be welded to disc body  20 . Knife adapter  30  further includes a cylindrical aperture  32  that is located concentric with a cylindrical aperture  22  of the disc body  20 , together defining the pivot axis of knife  50 . Knife  50  includes a cylindrical aperture  52 , sized to allow sleeve portion  12  of bolt  14  to pass through allowing sufficient clearance so that the knife  50  will pivot freely. The mounting arrangement is completed by installing bolt  14  through the aperture  52  of the blade  50 , then through the aperture  32  of knife adapter  30 , and finally through aperture  22  of disc body  20 , and into its mating nut  16 . 
     The top side of the disc body  20  is in contact with the material being cut, functioning to lift and propel the cut material away from the knife. It is exposed to significant wear, along with any components located on the top side of the disc  20 , such as nut  16 . If nut  16  is subjected to sufficient wear, the hex configuration of its outer surface can be degraded to the point that a wrench no longer mates adequately to allow removal. In order to protect the nut  16  from this excessive wear prior art mounting arrangements have included a wear protector  17  mounted on the top of the disc body, to protect the nut  16  from this excessive wear. 
     Disc  20  is adapted to provide for this mounting arrangement by providing mounting surface  24  on disc body  20  for supporting wear protector  17 . The disc  20  further includes a transition area to the raised portion  28 . This raised portion  28  tapers such that at the far outer diameter of the disc  20 , it does not exist. At lesser diameters the raised portion is increasingly larger. This raised portion  28 , and the transition area between it and the mounting surface  24 , provides protection for bolt  15 , which thus does not require a wear protector. 
     The knife adapter  30  often includes a tab  34  that prevents full rotation of the knife  50 , in order to control its location, in order to avoid interference with other components of the machine. 
     This mounting arrangement requires that the several pieces be disassembled with wrenches in order to maintain the knives which is costly and difficult due to the number of knives on a machine. 
     BRIEF SUMMARY OF THE INVENTION 
     According to the present invention there is provided an improved mounting arrangement for a knife to a disc for use on a rotary disc cutter that eliminates the need for a threaded connector and the associated nut, providing a positive retention method on the top side of the disc. In addition it provides a method of removing the knife from the disc without the use of wrenches, simply requiring a tool to pry, such as a screw driver. A further feature is a low profile retainer that does not need to be protected by a wear protector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a prior art mounting arrangement of a knife onto a mower disc; 
     FIG. 2 is a partial top plan view of a mower disc with knife mounted in accordance with the prior art as illustrated in FIG. 1; 
     FIG. 3 is a top plan view of a knife adapter of the prior art knife mounting; 
     FIG. 4 is a partial top plan view of the mower disc configured for the prior art knife mounting; 
     FIG. 5 is a top plan view of a mower disc with knives mounted in accordance with the present invention; 
     FIG. 6 is a bottom plan view of a mower disc with knives mounted in accordance with the present invention; 
     FIG. 7 is a cross-sectional side view of a mower disc, as defined by section line  77  in FIG. 6, with the knives mounted in accordance with the present invention; 
     FIG. 7 a  is a view like FIG. 7, but of a slightly modified version wherein the retainer is not completely flat in the retained position so that it is easier to get a screwdriver under it for removal at a later time; 
     FIG. 8 is a top plan view and an exploded view of the mounting arrangement of a knife onto a mower disc of the present invention; 
     FIG. 8 a  is an exploded view of FIG. 7; 
     FIG. 9 is a partial top plan view of the mower disc configured for the knife mounting arrangement of the present invention; 
     FIG. 10 is a top plan view of a blade retainer of the knife mounting arrangement of the present invention; 
     FIG. 11 is a top plan view of a knife adapter of the knife mounting arrangement of the present invention; 
     FIG. 12 is a top plan view of a mower disc with knives mounted in accordance with a second embodiment of the present invention; 
     FIG. 13 is a bottom plan view of a mower disc with knives mounted in accordance with a second embodiment of the present invention; 
     FIG. 14 is a cross-sectional side view of a mower disc, as defined by section line  14 — 14  in FIG. 13, with the knives mounted in accordance with a second embodiment of the present invention; 
     FIG. 15 is a partial top plan view of the mounting arrangement of a knife onto a mower disc of a second embodiment of the present invention; 
     FIG. 15 a  is an exploded view of FIG. 14; 
     FIG. 16 is a partial top plan view of the mower disc configured for the knife mounting arrangement of a second embodiment of the present invention; 
     FIG. 17 is a top plan view of a blade retainer of the knife mounting arrangement of a second embodiment of the present invention; 
     FIG. 18 is a top plan view of a knife adapter of the knife mounting arrangement of a second embodiment of the present invention; 
     FIG. 19 is a side view of a retaining pin of the present invention; 
     FIG. 20 is a side view of a second embodiment of a retaining pin of the present invention; 
     FIG. 21 is a top plan view of a retainer of the knife mounting arrangement of the present invention illustrating features to aid disassembly; 
     FIG. 22 is side view of an alternate embodiment of a retainer; and 
     FIG. 23 is a perspective view of the retainer in FIG.  22 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, like reference numerals designate identical or corresponding parts throughout the several views. The included drawings reflect the current preferred and alternate embodiments. There are many additional embodiments that may utilize the present invention. The drawings are not meant to include all such possible embodiments. 
     The FIGS. 5-7 illustrate a mower disc assembly  110  of the present invention. A disc  120  includes a center pilot hole  112  that controls its alignment and location when installed onto a cutter bar which is comprised of a series of gears, a supporting frame/housing, and driveline to transfer power from a tractor PTO to the cutterbar. Additional holes  114  allow retainers, not shown, to securely attach other components such as crop deflectors, not shown, to the mower disc. Two knives  50  are installed onto the bottom of disc body  120 , each with a knife adapter  130 , a pin  140  and a retainer  150 . The knife is free to rotate about pivot axis  116  until it contacts a tab  134  of the knife adapter  130 . 
     FIGS. 8-11 further illustrate a single knife mount of this embodiment of the present invention. The disc body  120  includes two cylindrical apertures  122  and  126 , and a mounting surface  124 , as illustrated in FIG. 9, on each side, for each knife  50 . It further includes a transition between the mounting surface  124  and raised portion  128 . 
     The knife adapter  130  includes a cylindrical aperture  132 , a tab  134 , and a cylindrical projection  136  as illustrated in FIGS. 8,  8 A and  11 . The knife adapter  130  is fixedly attached to the bottom side of disc body  120 , the preferred attachment method is welding, such that cylindrical projection  136  passes through aperture  126  of disc body  120  and extends above the mounting surface  124 . 
     Pin  140  includes a first cylindrical portion  142  with a diameter slightly smaller than the aperture  52  in the blade  50 , and a second cylindrical portion  144  that is slightly smaller than the aperture  122  of disc  120 . It also includes a head portion  148  with a diameter larger than the aperture  52  in the knife  50 . It further includes a retaining groove  146 , located on the second cylindrical portion  144 , with a width that slightly exceeds the thickness of retainer  150 , and has a groove diameter that is smaller than the diameter of the second cylindrical portion  144 . 
     Retainer  150  is made of a spring material of a thickness such that a significant force is required in order to deflect the retainer  150 , yet it can be deflected significantly without being permanently deformed. This thickness is equal to or less than the material thickness of the disc body  120 . It includes a key-hole shaped aperture  152  with a first end  154  and a second end  156 . The first end  154  is wide enough that retainer  150  can be installed over the second end  144  of pin  140 . The second end  156  of the key-hole aperture  152  is cylindrical with a diameter slightly larger than the groove  146  of pin  140 . 
     The blade  50  is mounted to the disc by passing pin  140  through the aperture  52  in knife  50 , then through aperture  132  in knife adapter  130  and aperture  122  in disc  120  such that groove  146  is located above surface  124 . Pin  140  is retained in this position by placing retainer  150  onto the pin, passing the first end of the key-hole aperture  152  over the second end  144  of pin  140  until the retainer is against the surface  124  of disc  120 . The retainer is then slid perpendicular (right in FIGS. 8 and 8A) to the pin  140 , such that the second end  156  of the keyhole shaped aperture  152  engages the groove  146 . 
     As retainer  150  is being slid along surface  124  a leading side  158  will come in contact with the ramped surface  138  of cylindrical projection  136  of knife adapter  130 , which is extending above surface  124 , through aperture  126  of disc  120 . In order to slide retainer  150  to its proper position the retainer will be deflected up the ramped portion  138  of knife adapter  130 . Upon reaching the installed position the retainer  150  will snap positively into place when first end of key-hole shaped aperture  152  slips over the cylindrical portion  136  of knife adapter  130 , at such time the retainer  150  will return back towards its unloaded position, where it is straight as illustrated in FIG.  8 A. Alternatively curved retainer  151 , with a slight bend, could be utilized. If the curved retainer  151  is utilized, then it will snap towards its unloaded position represented by this slightly curved shape. In this position as shown in FIG. 8, the retainer  150  is held in position by the cylindrical projection  136 . In order for it to move along surface  124  the leading side  158  of retainer  150  will need to be deflected far enough to clear the cylindrical projection  136  of blade retainer. In this manner, the pin  140  and knife  50  are retained to the disc  120 , and removal of a knife  50  can be accomplished simply by using a tool capable of prying the leading end  158  of retainer  150  up and over the cylindrical projection  136  to the point it can be slid along surface  124 . The removal operation is enhanced if the leading edge  158  is raised slightly above the top surface  124 . This slightly raised area can be provided by a slightly curved retainer  151 , or by providing an additional small step  139  as illustrated in FIG.  7 A. 
     This mounting arrangement of FIGS. 5-8 thus provides a knife retention system that includes a retainer with a material thickness less than the material thickness of the disc, and a pin which does not require substantial wear protection. The raised portion  128  of the disc body  120  adequately protects the pin  140 , thus there is no need for an additional wear protector. The overall height of the retaining components is small, minimizing the potential affect on the standing crop that is being cut. 
     FIGS. 12-14 illustrate a second embodiment of a mower disc assembly  210  of the present invention. A disc  220  includes a center pilot hole  212  that controls its alignment and location when installed onto a cutter bar. Additional holes  214  allow retainers, not shown, to securely attach other components such as crop deflectors, not shown to the mower disc. Two knives  50  are installed onto the bottom of disc body  220 , each with a knife adapter  230 , a pin  240  and a retainer  250 . The knife is free to rotate about pivot axis  216  until it contacts a tab  234  of the knife adapter  230 . 
     FIGS. 15-18 further illustrate a single knife mount of this embodiment of the present invention. The disc body  220  includes one slot-shaped aperture  222 , and a mounting surface  224 , as illustrated in FIG. 16, on each side, for each knife  50 . The previously described embodiment could also be implemented with a disc body configured in this manner, if the knife retainer  130  were configured in accordance. Disc body  220  further includes a transition between the mounting surface  224  and raised portion  228 . 
     The knife adapter  230  includes a cylindrical aperture  232 , a tab  234 , and a projection  236  shaped to fit into the slot-like aperture  222  of disc  220 , as illustrated in FIGS. 15 and 18. Projection  236  includes a surface  237  and further includes a top portion  238  with ramped tabs  260 . The knife adapter  230  is fixedly attached to the bottom side of disc body  220 , the preferred attachment method is welding, such that projection  236  passes through aperture  222  of disc body  220  and top portion  238  extends above the mounting surface  224  while surface  237  is in-line with mounting surface  224 , or is slightly raised above surface  224 . 
     As illustrated in FIG. 15A, pin  240  includes a first cylindrical portion  242  with a diameter slightly smaller than the aperture  52  in the blade  50 , and a second cylindrical portion  244  that is slightly smaller than cylindrical portion  244 . It also includes a head portion  248  with a diameter larger than the aperture  52  in the knife. It further includes a retaining groove  246 , located on the second cylindrical portion, with a width that slightly exceeds the thickness of retainer  250 , and has a groove diameter that is smaller than the diameter of the second cylindrical portion  256 . 
     Retainer  250  is made of a spring material of a thickness such that a significant force is required in order to deflect the retainer, yet it can be deflected significantly without being permanently deformed. It includes a key-hole shaped aperture  252  with a first end  254  and a second end  256 . The first end  254  is wide enough that retainer  250  can be installed over the second end  246  of pin  240 . The second end  256  of the key-hole aperture  252  is cylindrical with a diameter slightly larger than the groove  246  of pin  240 , and smaller than the diameter of the second end  244  of pin  240 . The retainer  250  further includes two notches  257 , one on each side. Retainer  250  will have an unloaded shape, which is flat as illustrated in FIG.  15 A. It could alternatively include a slightly bent portion at the leading edge  258 , to assist removal, as previously described for retainer  151 . 
     The blade  50  is mounted to the disc by passing pin  240  through the aperture  52  in knife  50 , then through aperture  232  in knife adapter  230  such that groove  246  is located above surface  237  or  224 . Pin  240  is retained in this position by placing retainer  250  onto the pin, passing the first end  254  of the key-hole aperture  252  over the second end  244  of pin  240  until the retainer is against the surface  224  of disc  220  or surface  237  of knife retainer  230 . The retainer is then slid perpendicular to the pin  240 , such that the second end  256  of the keyhole shaped aperture  252  engages the groove  246 . 
     As retainer  250  is being slid along surface  226  or  237  a leading side  258  will come in contact with ramped tabs  260  of knife adapter  230 , which extend above surface  224  and/or surface  237 , through aperture  222  of disc  220 . In order to slide to its proper position the retainer will be deflected up the ramped tabs  260  of knife adapter  230 . Upon reaching the installed position the retainer  250  will snap into place when notches  257  align with the ramped tabs  260  of knife adapter  230 , the retainer  250  returning back towards it unloaded position where it is straight as shown in FIG.  15 . In this position, the retainer  250  is held in position by the tabs  260 . In order for it to move along surface  224  or  237 , the leading side  258  of retainer  250  will need to be deflected up, far enough to clear the ramped tabs  260  of knife adapter  230 , before it can be slid along surface  224  or  237 . In this manner, the pin  240  and knife  50  are retained to the disc  220 , and removal of a knife  50  can be accomplished simply by using a tool capable of prying retainer  250  up to the point it can be slid along surface  124  or  237 . The prying tool can, for example, be a screw driver and the leading edge may be held from the surface  124  by a tab, such that the retainer  250  is slightly deflected in the installed position, or by the fact that the retainer includes a slight bend. 
     The ramped tabs  260  of knife adapter  230  and the cooperating notches  257  of retainer  250  in this second embodiment provide the same function as the projection  136  and first end  154  of aperture  152  of the first embodiment. These are examples of many different types of arrangements that could be utilized to secure the retainer to the knife adapter, or a different feature of the mower disc itself. 
     The retainers, as in retainer  150  and  250 , may include slot  300 , as illustrated in FIG. 21, which is provided for disassembly. The slot  300  will be sized and positioned such that a screwdriver, or the like will be able to be utilized to engage the slot in order to assist in prying on the retainer to slide it relative to the disc. 
     Additional slots, such as slot  302  shown in FIG. 21, or other surface features may be added in order that the retainers will break at defined locations during disassembly. Thus, when the retainer is pried-on to remove the knife, the section of the retainer that is engaged with the tabs or projections of the knife adapter or disc will separate from that portion that is engaged with the pin. This would allow both of the resulting pieces to be easily removed. 
     FIGS. 19 and 20 illustrate optional configurations of the grooves in the pin  140  and  240 . The grooves could be full annular grooves  247  as illustrated in FIG. 19, or slots  245 , one on each side as illustrated in FIG.  20 . 
     FIGS. 22 and 23 illustrate an additional embodiment of a retainer  350  with an additional curved section  352 . The end  354  is narrow enough to fit into the key-hole slot of the retainer, similarly shaped to the key hole slots in retainers  130  and  230 . The end  354  will then engage with the groove in the pin to increase the bearing surface under the pin head and providing a locking feature that prevents the retainer  350  from sliding. End section  356  forms a tapered profile, approximately paralleling the raised portion  128 ,  228  of disc  120 ,  220  such that the disc  120 ,  220  will protect it. 
     Obviously many modifications and variations of the present invention are possible in light of the above teachings, including variations in the shape of the knife mount pin and cooperating apertures in the knife adapter. It is known to use various configurations of these components, other than the herein specified cylindrical shapes. These would include conical sections, and could include pins with various cross-sections such as square or hexagonal. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Technology Classification (CPC): 0