Abstract:
An apparatus for mounting a blade to a cutting implement is provided. The apparatus includes an adapter which enables the blade to be fastened with the implement with structure that is offset from its axis of rotation. With this mounting capability, structure used to secure the blade relative to the cutting implement experiences decreases occurrences of tightening relative to the blade with which it is associated. Accordingly, there is presented an enhanced ability to remove the blade when such removal is desired.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to devices used in the mounting of a cutting blade to a cutting implement, and more specifically, to structure used in reducing unwanted movement of the blade and the effect of destructive forces exerted on the blade and its mounting apparatus as a result of the blade operation and impacts from objects during that operation.  
         BACKGROUND OF THE INVENTION  
         [0002]    Often, the blade or blades of a cutting implement are mounted through the use of a bolt or nut arrangement. The bolt is ordinarily passed through an opening in the center of the blade and is centered across the width of the spindle housing so as to be inline with the spindle shaft. Interposed between the bolt head and the blade, a washer has been provided which, along with the bolt, creates a clamping force to hold the blade to the spindle shaft as it and thus, the blade, are turned. Each of these is rotated upon activation of a power transfer system, such as a series of belts and pulleys, which transmits power from a mower or tractor engine to spin the blade and cause it to move about its axis of rotation which extends through the spindle shaft and the middle of the blade itself.  
           [0003]    Mounting the blade in the above manner whereby its surface is abutted against the spindle housing on one side and secured thereto by a spindle bolt or nut on its opposite side results in the creation of a friction joint between the blade and the spindle bolt or nut. This friction force is created by the surface contact existing between the blade and the tightened bolt and/or nut securing the blade to the surface of the spindle shaft. This joint often becomes disturbed or shifted whereby the bolt or nut is tightened to a point where it is difficult to remove and allow for the disassembly of the blade from the shaft.  
           [0004]    Tightening of the above joint has often occurred in two instances. First, as the power transfer system is started and power is transmitted to the blade to allow it to rotate, the bolt and washer spin together and naturally tighten as a result of the spinning of the blade. This occurrence can be referred to as a self-tightening of this mounting structure against the blade and surface of the spindle shaft. Second, the bolt may be tightened against the washer and blade as a result of objects contacting or impacting the blade. Accordingly, portions of the blade become repositioned relative to the bolt and washer which places unintended pressure on the joint causing the bolt to become further tightened against the blade. Thus, tightening of the blade joint may occur in two situations which have caused the bolt or nut secured against the blade to become difficult to remove when maintenance on the blade is attempted.  
           [0005]    Thus, it would be beneficial to provide a mounting assembly or arrangement which reduces the likelihood that structure used to secure the blade relative to the spindle housing will not tighten upon operation of the blade, including those instances in which the blade is impacted.  
         SUMMARY OF THE INVENTION  
         [0006]    Accordingly, there is provided an assembly that reduces the occurrences of tightening of the structure used to fasten the blade relative to the spindle housing and thus, the cutting implement, as the blade is operated.  
           [0007]    The assembly consists of an adapter which is mounted so as to contact the spindle housing on a first surface thereof and the blade on its opposite surface. The spindle is passed through the adapter and matingly engages it. On opposite ends or sides of the adapter, apertures are provided to retain bolts used to secure the blade against the adapter and thus, the spindle housing.  
           [0008]    To minimize tightening of the bolts and/or the adapter against the blade, the above assembly mounts the blade at two locations which are offset from the axis of rotation of the blade and the spindle with which it is associated. In doing so, the friction force existing between the mounting structure, the blade and the surface of the spindle shaft substantially at the axis of rotation, as in past designs, is greatly reduced. Accordingly, tightening of that mounting structure to the blade and spindle shaft as a result of the blade spinning is likewise diminished. Accordingly, removal of the blade is made easier.  
           [0009]    Power is transferred to the blade through use of the adapter. To do so, the adapter is constructed to include a hexagonal feature which accepts a similarly constructed head or extension on the end of the spindle.  
           [0010]    Thus, there is provided an assembly which reduces instances in which structure used to fasten the cutting blade relative to the spindle housing tightens upon operation of the blade. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a front and side elevated perspective view of a cutting implement including the blade mounting apparatus of the present invention.  
         [0012]    [0012]FIG. 2 is a front perspective view of the underside of the cutting implement showing the blade mounting apparatus.  
         [0013]    [0013]FIG. 3 is a front perspective view showing the blade mounting apparatus detached from the cutting implement and the blade which is to be secured thereto.  
         [0014]    [0014]FIG. 4 is an enlarged view of the blade mounting apparatus of the present invention.  
         [0015]    [0015]FIG. 5 is a sectional view according to lines  5 -- 5  as shown in FIG. 1.  
         [0016]    [0016]FIG. 6 is front and elevated view of a cutting implement having a blade mounting apparatus of the prior art. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    Looking to FIG. 1,there is shown a cutting implement  10  usable with a lawn and garden tractor (not shown). The implement  10  is ordinarily suspended from the tractor by suitable connections therewith (not shown) at its rear  12  and includes several anti-scalp wheels  14  at its front  16 . On a top surface  18  of the implement  10 , there is shown the top portion  20  of a blade spindle housing  22 . At the end of the top portion  20 , a nut  24  is provided which matingly engages the spindle to which the blade is attached, as discussed below.  
         [0018]    Focusing now on FIG. 2, the underside of the implement is shown. As can be seen, the bottom portion  26  of the spindle housing  22  is shown and against which is abutted an assembly  28  for mounting a cutting blade  30  relative to the housing  22 .  
         [0019]    With reference to FIGS. 3 and 4, the assembly  28  for mounting the blade  30  to the spindle housing  22  and the manner in which the blade  30  fastens to the assembly  28  is shown. The assembly  28  consists of a base member or adapter  32  having first and second apertures  34 ,  36  on its bottom surface  38  thereof for receiving coupling members or bolts  40  which are secured through use of nuts  42  on a top surface thereof as shown in FIG. 5. Intermediate the apertures  34 ,  36  is a third aperture  44  which receives a cylindrical member or spindle  46  used to hold the blade  30  and the adapter  32  relative to the spindle housing  22 . As shown more closely in FIG. 4, the third aperture  44  is provided, preferably, with a hexagonal cross-section which receives a similarly constructed fastening head or extension  48  included on the end of the spindle  46 . Although the preferred cross-section of the extension  48  is hexagonal, it is contemplated that any cross section having substantially non-circular mating portions could be used. Adjacent the extension  48  is a round extrusion  49 , provided as a portion of the spindle  46 , which is inserted through an aperture  64  and assists in centering the blade relative to the assembly  28 .  
         [0020]    As shown in FIG. 5, the assembly  28  mounts with the blade  30  and the housing  22  in a relatively simple manner whereby each of the blade  30 , adapter  32  and spindle  46  are shown therein. With reference to both FIGS. 3 and 5, it can be seen that the blade  30  is fastened against the adapter  32  by the bolts  40  and that the spindle bolt  46  is passed through the adapter  32 . As the bolt  46  passes through the adapter  32 , the extension  48  seats within the third aperture  44  whereby the spindle  46  is then inserted into the spindle housing  22 . At its end opposite the adapter  32 , the top of the spindle  46  is secured with the housing  22  by the nut  24 . Construction in this manner permits power to be transmitted to the adapter  32  and blade  30  and eliminates disadvantages associated with the friction joint as is seen in FIG. 6. Advantageously, the assembly  28 , through use of the adapter  32 , avoids difficulties associated with the friction joint. The adapter  32  exerts and distributes shear forces, instead of rotational forces, on the bolts  40  since they are offset from or not inline with the spindle bolt  46  and its axis of rotation. Accordingly, the likelihood of the unintended tightening of the bolts  40  or the adapter  32  to the blade  30  is decreased.  
         [0021]    Further, as seen in FIGS. 3 and 4, the adapter includes a large flat surface area  58  on its bottom  60 . This flat area  58  includes flanged or downwardly sloped portions  62 . Both the flattened area  58  and the sloped portions  62  serve to embrace or interface with mating portions of the blade  30  as can be seen throughout the exploded and unexploded portions of FIG. 3. With this configuration, the blade  30  will have a flattened area of substantially equal size to that of the area  58  to permit it to be engaged against the flattened area  58  and be secured on either side thereof with the bolts  40 . As a result of this mounting and contact between the area  58  and the surface of the blade  30  as well as the uniform cross-sectional configuration along length of the blade  30  including the area between where the bolts  40  connect the blade  30  to the adapter  32 , the blade  30  and its ends are enabled to resist being moved vertically relative to the housing  26 , especially in instances in which objects impact the blade  30 . Additionally, the blade  30  is held stable against the adapter  32  during operation so as to further ensure that the level of cut, and even nature thereof, is substantially maintained. Such mounting with the adapter  32  also permits blades of varying thickness to be held stable when operating.  
         [0022]    In FIG. 6, the conventional mounting of a cutting blade to a spindle housing can be seen. With that mounting, the blade  50  is held against the spindle housing  52  with a washer  54  and bolt  56  which extends into the housing  52  and is directly inline with the spindle shaft contained within the housing  52 . With this mounting method, tightening of the bolt  56  and washer  54  against a first surface of the blade occurs as the blade spins against the housing  52  on an opposite surface thereof. This is especially true in instances in which objects impact the blade and cause the distance between the bolt  56 , washer  54 , blade  50  and housing  52  to deviate from their original distance when initially adjusted. As described previously, other instances of tightening due to objects impacting the blade when it is spinning can occur when use of the friction joint shown is undertaken.  
         [0023]    With respect to the operational aspects of the blade  50 , mounting it to the housing  52  with a single bolt  60  across a flattened area often causes disadvantages other than those of tightening. For example, due to the blade not having flanged portions, as discussed with respect to the instant invention, it is less stiff whereas it includes a decreased ability to resist forces which are applied to it. This results since the sides of the blade  50  at their mounting location to the housing  52  have no material, or surface against which such material may be in contact, to otherwise absorb the applied force. Consequently, in the instance in which objects impact the blade, the blade  50  may not be as stiff as it could be causing the ends of the blade to sometimes move vertically with respect to the housing  52 . Such a condition often causes undesired instances in which the eveness of the level of cut is disrupted.  
         [0024]    Moreover, there exists a tendency, which the instant invention addresses through its mounting structure, for the blade  50  to stray from an even cutting plane so as to deliver a jagged or uneven level of cut. This tendency results, in part, from the small flattened cross-sectional area existing in proximity to the bolt  56  whereby the area has minimal structure to assist in minimizing instances of fluttering which may be described as the movement of the lateral ends or tips of the blade above and below the cutting plane as the blade is operated.  
         [0025]    Accordingly, there is provided an assembly for mounting the blade relative to the spindle housing whereby the components of that assembly are constructed and situated to adapt to the blade in a manner that reduces the likelihood of their tightening.  
         [0026]    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.