Abstract:
A mower blade with a trailing sweeping edge that projects below the cutting edge serves to brush, cut particles deposited on the grass surface down between the grass blades and up into the air stream within the mower deck. As the cut particles are recirculated in the air stream, they are recut in a mulching action. The particles forced down between the grass blades reduce the amount of cut grass that has to be discharged. As a result, the amount of cut grass particles left on the lawn is reduced, thereby providing an improved appearance.

Description:
FIELD OF THE INVENTION 
     The present invention relates to mower decks for cutting grass and similar vegetation and more specifically to a blade that improves discharge of cut material from the deck and reduces the accumulation of cut material on the surface of the lawn. 
     BACKGROUND OF THE INVENTION 
     The great majority of yard and landscaped grasses are cut with mower decks. When the grass to be cut is long and/or wet, the cut particles may not be as efficiently discharged from the deck. 
     To reduce the inconvenience associated with discharging and/or collecting cut grass, mulching decks have grown in favor. With a mulching deck, the grass is recirculated within the air stream of the cutting chamber, causing it to be recut several times into smaller and smaller pieces and then forced by the air stream down and into the spaces between the standing blades of grass. While this mulching process eliminates the need to keep the long and/or wet grass particles airborne long enough to discharge them, it can leave clipping drops or clumps of cut grass on the surface of the lawn. 
     Therefore, it would be desirable to provide a mower blade that helps to recirculate cut particles so that they can be recut, more easily remain airborne and more efficiently be discharged. 
     Further, it would be desirable to provide a blade that would reduce the incidence of clipping drops or clumps left on the cut grass surface. 
     SUMMARY OF THE INVENTION 
     Toward these ends, there is provided a blade for use in a rotary mower deck for cutting grass and similar vegetation. The blade includes a sweeping edge along the surface trailing the cutting edge. The sweeping edge projects below the horizontal plane of the cutting edge to brush the top portion of the cut grass blades and lift some portion of the cut particles laying thereon back into the swirling air stream within the cutting chamber. As the cut grass particles are lifted to be recirculated and recut, they are lighter and it is easier to keep them airborne for discharge. The brushing effect of the sweeping edge further serves to force cut grass particles downwardly into the spaces between the blades of uncut grass. As a result, the finished appearance of the cut lawn is improved as is the discharge of cut material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevated side perspective view of a blade made in accordance with the present invention. 
     FIG. 2 is a side view of the cutting blade illustrated in FIG.  1 . 
     FIG. 3 is an end view of the cutting blade illustrated in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Looking first to FIG. 1, there is illustrated an elevated perspective view of a rotary mower cutting blade,  10  utilizing the improvement of the present invention. The blade  10  is of the type that could typically be mounted on a mower deck as would be used with lawn, lawn and garden tractors and similar vehicles. 
     The elongated mower blade  10  includes a center portion  12  adapted to support it for rotation in a generally horizontal plane. The support, while not shown, would typically be comprised of a bolt attaching it to a spindle. The spindle would be powered by a belt or gear driven structure carried on the mower deck. Adjoining the opposite sides of the center portion  12  are end portions  14  which are integrally formed as a part of the blade  10 . The end portions  14  are essentially reverse images of one another and in all material respects will be identical. Accordingly, only one end portion  14  and its structure need be discussed in detail. 
     The end portion  14  carries a leading surface  16  and a trailing surface  18 . The leading surface  16  is in front as the blade  10  is rotatably driven by the power source. As viewed in FIG. 1, the blade  10  would be rotated in a clockwise direction and the leading surface  16  is on the upper right hand side of FIG.  1 . Along the leading surface  16  of the blade  10  is carried a cutting edge  20 . This cutting edge  20  is comprised of an outer cutting edge portion  22 , a mulch hump cutting portion  24  carried by a mulch hump  26  and an inner cutting portion  28  having a terminal end  30 . The cutting edge  20  extends between the outer end  32  of the end portion  14  and extends inwardly approximately one-half of the distance to the mounting hole or opening  34  of the blade  10 . Between that terminal end  30  of the cutting edge  20  and the mounting hole  34  is a structural support portion  36  of the blade  10  that carries the end portion  14 . 
     Along the rear half of the outer tip of the end portion  14  is carried a wing section  38  that is designed to lift and throw material cut by the cutting edge  20  of the blade  10 . The wing section  38  further serves to create an air stream within the cutting chamber that acts to lift the grass blades for cutting. 
     As noted, a mulch hump  26  is provided at the leading surface  16  between the outer cutting edge  22  and the inner cutting edge  28 . The purpose of the mulch hump  26  is to provide additional cutting at a different height of grass than is provided by the outer cutting edge  22 . By being at a different level, it will cut grass into smaller pieces. It also helps direct grass downwardly into the standing grass blades. 
     At the trailing surface  18  of the blade  10 , as can best be seen in both FIGS. 1 and 2, is provided a sweeping edge  40 . The sweeping edge  40 , as can be seen in FIG. 2, projects downwardly below the plane  42  of cutting provided by the cutting edge  20  and extends approximately ⅓ of the way across the blade  10 . While the preferred embodiment includes an uplifted wing  38  and a mulch hump  26 , non-mulching blades could be provided with a sweeping edge  40  that extends all the way to the outer end  32  of the blade  10 . 
     In operation, the blade  10 -would be rotatably carried on a bolt or shaft extending through the mounting hole  34  provided in the center of the blade  10  and rotate about a vertical axis with the blade  10  moving in a generally horizontal plane. As the blade  10  is advanced across the grass or lawn, the cutting edge  20  would sweep in a circle to cut the grass along the complete sharpened cutting edge  20 . The primary cutting to the desired height would occur along the generally horizontal outer cutting edge portion  22  of the cutting edge  20 , which would be generally parallel to the ground. Further cutting of the grass at a different height would occur at the mulch hump cutting edge portion  24  and again at the interior cutting edge portion  28 , with each of these cutting actions occurring at different heights to chop the grass into small pieces. As the blade  10  rotates in a circle while being advanced, the cutting edge  22  would sweep through the path originally swept by the mulch hump cutting edge portion  24  and the inner cutting portion  28  to cut the grass to the proper height. During this cutting activity, the wing  38  would be lifting and throwing the material as well as generating an air stream within the cutting chamber of the deck. This would continue to provide a swirling motion of the cut grass and air within the chamber to recut and recut the grass particles as they are recirculated. 
     At the rear surface  18  of the blade  10 , the sweeping edge  40  would contact the top edge of the cut grass blades, brushing them down. This brushing effect would serve the purpose of cleaning any accumulated materials that fall on top of the grass from the top of the grass to bring them back up to be recirculated in the swirling air stream within the cutting chamber. Further, as the sweeping edge  40  brushes the grass, it would open up areas between the blades of grass for the cut particles to fall down into. The pressure created by the air stream would further serve to force the cut particles down between the standing grass blades. 
     Through brushing the top of the grass, the sweeping edge  40  reduces the frequency of the occurrence of clumping or dropped grass on top of the lawn surface. While the preferred embodiment of the blade  10  utilizes a mulching design, this sweeping area  40  could be provided to blades not having the mulch design nor having the uplifted wing  38 . Accordingly, the sweeping edge  40  could be provided along the whole trailing edge  18  of the blade  10  directly behind the cutting edge  20  on the leading surface  16  of the blade  10 . 
     The present blade design is contemplated to be used on a single spindle deck or a deck having a plurality of blades and accordingly the advantages flowing from the design could be realized with those variations in application. 
     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.