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RELATED APPLICATION DATA 
     Priority Claim 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/903,557, filed Feb. 27, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to excavating equipment and machinery, and in its preferred embodiments more specifically relates to an excavating attachment for the forward lip of a front end loader bucket. 
       BACKGROUND 
       [0003]    Front end loaders, whether dedicated pieces of equipment or general purpose tractors with a front end loader attachment, are widely used in a variety of activities, including construction, farm and ranch work, and landscaping work. A typical front end loader bucket has a relatively flat bottom wall, a rear wall, and a pair of opposed side walls connected between the rear wall and side edges of the bottom wall. The front of the loader bucket is open, over a planar forward lip. Most commonly, a front end loader is used to scoop, lift, and transport relatively loose materials that have previously been loosened or placed with another piece of equipment. However, in many instances it is desirable or expedient to use a front end loader for at least shallow excavation work, with the forward lip of the loader bucket performing a digging or breaking function. Front end loaders are also commonly used to lift and transport heavy items such as stumps, log sections, and large rocks. 
         [0004]    The flat, straight forward lip of a loader bucket is not well suited for excavation, and use of a front end loader with a conventional lip is inefficient and often ineffective for that purpose. It can also be difficult to engage objects such as logs and rocks to move them into the loader bucket for transport. Most excavating implements are provided with forward extending teeth connected along the forward lip of the excavator bucket or shovel, to break up the soil or other material so it can be more easily scooped into the bucket. In excavator implements the teeth may be individually mounted to the forward lip of the bucket, or the teeth may be mounted on a plate that is attached to the forward lip of the bucket. 
         [0005]    Excavator attachments for a front end loader bucket are known in the prior art, provided for the purpose of converting a conventional loader bucket to a more effective excavator bucket. Such attachments include a bar with a plurality of teeth connected to the bar, which is itself connected to the forward lip of a loader bucket by a plurality of bolts extending through the bar and the bottom wall of the bucket adjacent to the forward lip, to secure the attachment tightly against the lip. Individual teeth may also be mounted on the forward lip of a loader bucket, also by bolts. Although such attachments can be effective for excavation, the use of bolts through the lip of a loader bucket for connecting excavator attachments has disadvantages and drawbacks. The placement and removal of an array of bolts along the entire lip is a time consuming procedure. In addition, bolts and nuts arrayed along the forward lip of the bucket are exposed to continuous wear and abrasion, and after even a relatively short period of use removal of the bolts can be both difficult and time consuming. Further, conventional, wedge-shaped excavator teeth can be ineffective in engaging an object such as a log and flipping it into the bucket, because the object tends to slide forward off the teeth in the process of attempting to tilt and lift the bucket. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides an excavator attachment for a loader bucket that does not require the use of bolts along the forward lip of the loader bucket for attachment. The attachment of the invention includes a plurality of teeth disposed along and connected to a bar. Each tooth is formed with a groove to be received over the forward lip of a loader bucket, with a portion of each tooth above the lip and a portion below the lip. The bar includes a connection flange at each end and is connected to the bucket by bolting the flanges to the side walls of the bucket. The bar is not connected to the bottom wall of the bucket, eliminating bolts through the lip, and is retained in place by the extension of the lip into the grooves formed in the teeth. 
         [0007]    The teeth connected to the bar are preferably formed with a slightly concave upper surface to facilitate engaging and lifting objects. The concave curvature of the upper surface of the teeth allows the point of the teeth to slide under an object more readily than wedge-shaped teeth with a straight upper surface. When the bucket is tilted the object to be lifted will roll slightly into the concavity and can be much more easily flipped backward into the bucket. 
         [0008]    The structure and features of the excavator attachment of the invention will be described below with reference to the accompanying drawing figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a front perspective view of a preferred embodiment of the excavator attachment of the invention, connected to a loader bucket. 
           [0010]      FIG. 2  is a top plan view of a preferred embodiment of the excavator attachment of the invention. 
           [0011]      FIG. 3  is a side elevation view of a preferred embodiment of the excavator attachment of the invention. 
           [0012]      FIG. 4  is a side elevation view of a preferred embodiment of a tooth component of the excavator attachment of the invention. 
           [0013]      FIG. 5  is a sectioned side elevation view of a preferred embodiment of the excavator attachment of the invention in place on and connected to a loader bucket, viewed along line  5 - 5  of  FIG. 1 . 
           [0014]      FIG. 6  is a side elevation view of an alternative embodiment of a tooth component of the excavator attachment of the invention. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0015]    The preferred embodiment of the excavator attachment of the invention, generally designated by reference number  10 , includes as its primary components a mounting bar  11  and a plurality of teeth  12 . 
         [0016]    Mounting bar  11  is formed as an elongate planar, generally rectangular plate of substantially greater length than width, and of greater width than thickness, with a first end  13 , a second end  14 , a forward edge  15  and a trailing edge  16 . Forward edge  15  is preferably beveled or inclined to form a chisel point, as illustrated in the drawing figures, so as to provide a smooth transition for materials to move past the mounting bar. Mounting bar  11  also has an upper face  17  and a lower face  18 . A planar, generally rectangular attachment flange  19  is connected to each end of bar  11 , with the plane of each attachment flange generally perpendicular to the plane of bar  11 , and with the attachment flanges extending in mutually parallel relation upward from upper face  17  of the bar. Each of attachment flanges  19  is penetrated by a bolt aperture  20 . In the preferred embodiment bar  11  is continuous, without any apertures or other penetrations for connecting bar  11  to a loader bucket. 
         [0017]    Flanges  19  may be formed as separate components and connected to bar  11  by, e.g., welding, or flanges  19  may be integrally formed with bar  11  by bending the ends of the bar to form the flanges. Bar  11  and flanges  19  are preferably formed of steel-plate, but it is to be understood that the scope of the invention is not limited to any particular material of construction, and other materials with suitable strength and rigidity could be used if desired. The total length of bar  11  with flanges  19  is generally equal to the width of the forward lip of the loader bucket, between the side walls of the bucket. 
         [0018]    Each tooth  12  is preferably formed as a solid body  21  with a leading end or point  22 , a rear end  23 , an upper face  24 , a lower face  25 , and side faces  26 . Upper face  24  and lower face  25  converge at the leading end  22  of the tooth to join and form a chisel or cutting tip at the leading end. It is preferred that the upper face  24  of each tooth be formed with a concave curvature, in order to facilitate “flipping” solid objects, such as logs or rocks, into the bucket. The concave curvature of the upper face allows the leading ends of the teeth to more easily slip under such an object, so that the object tends to roll backward onto the teeth and is slightly cradled in the concavity. The object is then more likely to roll backward into the bucket when the bucket is rotated upward, rather than slipping forward off the teeth as is often the case with teeth having a linear or convex upper face. However, although the concave configuration of the upper face of the teeth is preferred, it is to be understood that other configurations may be used within the scope of the invention. 
         [0019]    A groove  27  is formed in each tooth  12 , extending into the body of the tooth from the rear end  23  toward the leading end, intermediate between upper face  24  and lower face  25 . Groove  27  extends across the full width of tooth  12  between side faces  26  and through those faces, so that groove  12  is open at the rear and the sides of the tooth. Each groove  27  has an upper face  28  and a lower face  29  The depth of each groove  27  from the rear of the tooth to the inner end  30  of the groove is greater than the width of bar  11  between leading edge  15  and trailing edge  16 . In the preferred embodiment the depth of each groove is approximately twice the width of bar  11 , but it is to be understood that the specific proportional relationship is not critical and may be varied within the scope of the invention. 
         [0020]    In the preferred embodiment the distance between the upper and lower faces  24  and  25  of groove  27  is not the same through the depth of the groove, but is increased through the portion of groove  27  adjacent to the rear of tooth  12  to form a notch  31  in the upper face of the groove. Notch  31  is configured and dimensioned to receive bar  11  in the notch, with the distance of extension of notch  31  inward from the rear of the tooth approximately equal to the width of bar  11  between edges  15  and  16 , and the distance of extension of notch  31  toward the upper face of the tooth approximately equal to the thickness of bar  11  between its upper and lower faces. Although it is preferred that notch  31  be formed in the upper face of the groove, it is to be understood that the notch could readily be formed in the lower face of the groove. With the notch formed in the upper face of the groove, the mounting bar will be disposed above the lip of the bucket, whereas with the notch formed in the lower face of the groove, the mounting bar will be disposed beneath the lip of the bucket. 
         [0021]    Each tooth is disposed on bar  11  with bar  11  received in notch  31 , and each tooth  12  is connected to bar  11 . The preferred manner of connection is welding, but other means of connection, such as counter-sunk nuts and bolts, could be used. After connection of each tooth  12  to bar  11 , the lower face  18  of the bar within each groove  27  is parallel to and aligned with the upper face  28  of the portion of the groove between notch  31  and the inner end  30  of the groove. Each groove  27  is configured and dimensioned to match the configuration and dimensions of the forward lip of the loader bucket to which the excavator attachment is to be connected, since there are variations among different manufacturers. Generally, the height of each groove between its lower face and either the upper face of the groove or the lower face of bar  11  is approximately equal to the thickness of the forward lip of the loader bucket. 
         [0022]    The excavator attachment of the invention is connected to a loader bucket by positioning the attachment parallel to the forward lip of the bucket, with the rear of teeth  12 , and the opening  32  of grooves  27  facing the lip of the bucket. The attachment is moved toward the bucket so that the lip of the bucket is received in grooves  27 , and bar  11  is received along the upper face of the bottom wall of the bucket adjacent to the forward edge with the lower face of bar  11  flat against the bottom wall of the bucket. With the forward lip of the bucket fully received in grooves  27 , flanges  19  are received against the respective side walls of the bucket. A bolt aperture is formed in each side wall of the bucket in alignment with the respective bolt aperture  20  in the respective flange. A bolt  33  is extended through each set of aligned apertures in flanges  19  and the bucket side walls and secured by a nut  34 , to securely connect the excavator attachment to the loader bucket. Bolts  33  serve primarily to retain the excavator attachment in place, and the primary strength of the connection between the attachment and the loader bucket is provided by the interlock of the lip of the bucket in grooves  27 , eliminating any need to secure bar  11  to the loader bucket along the length of the bar. 
         [0023]    The excavator attachment of the invention is removed from the loader bucket by removing nuts  34  from bolts  33  and removing the bolts from the apertures in flanges  19  and the side wall of the bucket, freeing the attachment from connection to the bucket and allowing it to be easily pulled forward from the lip, or the bucket to be pulled away from the attachment, removing the lip of the bucket from grooves  27 , fully disengaging the attachment from the bucket. 
         [0024]    With the excavator attachment of the invention, bolts  33  and nuts  34  are relatively isolated from the abrasion and wear to which bolts and nuts used to connect attachment devices of the prior art are subjected, and the risk of damage to bolts  33  and nuts  34  is substantially reduced if not fully eliminated. Because the placement of only two bolts and nuts is required for connection of the excavator attachment, and the removal of only two bolts and nuts for disconnection, the excavator attachment of the invention can be connected and disconnected much more easily, and in much less time, than loader bucket attachments of the prior art. 
         [0025]    The foregoing description of the excavator attachment of the invention is intended to be illustrative and not limiting. The excavator attachment is susceptible to alternative embodiments and variations within the scope of the invention, as set out in the following claims.

Summary:
An excavator attachment apparatus for converting a loader bucket to an excavator bucket and from an excavator bucket back to a loader bucket includes an elongate mounting bar to be connected only to the side walls of the bucket and extend along the lip of the bucket between the side walls, and a plurality of teeth connected to the mounting bar, with each tooth having an open groove extending into the tooth, the groove to be extended over the lip of the bucket to firmly hold the excavator attachment on the lip of the bucket without direct connection to the lip.