Abstract:
An excavation retention assembly is provided for mounting a tooth to an excavating apparatus. The assembly in one embodiment includes a tooth and an adaptor end of a working member of an excavating apparatus. The tooth includes a cavity for mating with an end of the adaptor, an opening for receiving a fastening member and a fastening receptacle in the cavity opposite the opening in the tooth for receiving the fastening member. The adaptor includes a passage which aligns with the opening in the tooth and the fastening member. The fastening member passes through the aligned opening of the tooth, the passage of the adaptor and into the fastening receptacle for securing the tooth to the adaptor.

Description:
RELATED APPLICATION 
     This is a continuation-in-part of application Ser. No. 12/068,602, filed Feb. 8, 2008 now U.S. Pat. No. 7,788,830, for “EXCAVATION RETENTION ASSEMBLY” and incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an improved assembly for affixing replaceable machine parts and, in particular, an assembly which permits the retention and removal of replaceable machine parts, such as teeth and shrouds on heavy mining and construction equipment working members, such as mining shovels, excavator buckets, backhoe buckets and other earth moving tools. 
     BACKGROUND OF THE INVENTION 
     Heavy construction equipment, such as backhoes and other earth moving devices often have excavator buckets, shovels or other tools with projecting teeth. Often, a cutting surface is applied or affixed to an exterior surface of the teeth. Typically, the teeth are attached to the excavator device or working member using bolts and/or pins, which are used to couple or retain the teeth to a respective adaptor or adaptor end of the working member. During use of such working members, peak loads applied to the teeth create high shearing stresses that may wear the teeth and/or assembly, requiring replacement. Traditionally, the removal and/or installation of the teeth to the adaptor require the use of a hammer, which is time consuming and, in some instances, a difficult process. 
     SUMMARY OF THE INVENTION 
     The present invention provides an assembly for quickly and easily attaching or retaining a tooth or similar structure to an adaptor or adaptor end of a cutting edge of construction and mining equipment, such as buckets, shovels or other tools. The assembly provides a retention assembly that allows for the removal or installation of the teeth or similar structure to the adaptor without the use of a hammer. 
     The present invention, in one form, relates to a retention assembly for mounting a tooth to an adaptor of an excavating apparatus. The retention assembly includes an adaptor, a tooth and a means for securing the tooth to the adaptor. The tooth includes an exterior cutting edge for providing the work function. The tooth includes an interior cavity for receiving an end of the adaptor. The interior walls of the tooth cavity are tapered and constructed and arranged to generally mate with the adaptor. The tooth further includes an opening for receiving a fastening means such as a bolt for fastening the tooth to the adaptor. The tooth further may include a recess in the interior cavity wall opposite the opening for receiving a fastening receptacle for engaging the fastening means inserted through the opening in the opposite wall of the tooth. The adaptor includes an end portion having tapered walls constructed and arranged to generally correspond to those of the tooth cavity and to mate with the cavity of the tooth. The tooth is slidably mounted onto the adaptor such that there is minimal play between the tooth and the adaptor. However, the tooth is not so tightly held as to wedge and lock tight on the adaptor, which would require removal by hammer or other means. The tapered walls of the adaptor preclude rotation of the tooth in any direction and any linear movement in all directions, except the forward direction. In the forward direction, the tooth is constrained by the fastening member. 
     The adaptor further includes an opening in the end portion constructed and arranged to align with the opening in the tooth and the fastening receptacle in the tooth. A fastening means is placed through the opening in the tooth, through the opening in the adaptor and engages an opening in the fastening receptacle. The fastening means is preferably a bolt comprising a first end having a means for inserting or removing the fastening means such as a ratchet end. The fastening means includes a second end having means for engaging the fastening receptacle such as threads. As stated above, the fastening means is inserted through the openings in the tooth and adaptor and engages the fastening receptacle for securing the fastening means in place to retain the tooth on the adaptor. 
     The fastening receptacle includes an opening for receiving the fastening means. It includes a top face which is generally flat and which engages a face of the adaptor. The fastening receptacle further includes a bottom face which is seated in the recess of the tooth. The fastening receptacle includes interior walls adjacent the opening for engaging a fastening member such as a threaded nut. A preferred fastening member is a hexagonal nut. When such hexagonal nut is used, the interior walls of the fastening receptacle are also hexagonal to hold the nut in place and keep it from rotating when engaging the fastening member. Additionally, a lock washer such as a Belleville spring washer may be utilized to maintain the fastening means clamp load and, therefore, preclude the possible need for tightening the fastening means from time to time. The fastening receptacle is placed in the recess of the interior wall of the tooth. There is sufficient clearance on the top and sides of the fastening receptacle and the recess of the tooth for receiving a durable polymer resin such as a polyurethane elastomer which may be poured around it and which then hardens to encapsulate the fastening receptacle in the wall of the tooth. 
     When it is desired to install a tooth to an adaptor, the tooth is slidably mated with the adaptor such that the tapered walls of the adaptor are adjacent to the corresponding tapered walls of the tooth. A fastening means such as a bolt is placed through the opening in the tooth and passes through the corresponding opening in the adaptor. The threaded end of the fastening means engages the fastening receptacle. The fastening means is then secured to the fastening receptacle. In a preferred embodiment, the fastening means is a bolt having a head with a ratchet means and a threaded end, and the fastening receptacle includes a threaded nut and optionally a lock washer such as a Belleville spring washer for receiving the bolt. When ratcheting the bolt into the nut, the upward force from the fastening means as it is tightened when passing through the nut in the fastening receptacle pushes up on the fastening receptacle and causes the polymer layer around and above the receptacle to distort upward against the face of the adaptor and into the hole of the adaptor to further aid in securing the tooth to the adaptor. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective view of an excavating apparatus working member and the retention assembly in accordance with the present invention; 
         FIG. 2  is an exploded perspective view of the retention assembly of the invention shown in  FIG. 1 ; 
         FIG. 3  is a partial cross-sectional exploded view of the retention assembly of  FIG. 2  illustrating the tooth, the adaptor and the fastening means; 
         FIG. 4  is a perspective top view of the fastening receptacle which is inserted into an interior wall of the tooth; 
         FIG. 5  is a perspective bottom view of the fastening receptacle of  FIG. 4 ; 
         FIG. 6  is a cross-sectional side view of a portion of another embodiment of the retention assembly including a Belleville spring washer; and 
         FIG. 7  is a perspective view of the Belleville spring washer shown in cross-section in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described with regard to the several views of the drawings, where like numbers are identified using like numbers among the figures. It is to be understood that the excavation retention assembly of the invention may have a number of uses, including for excavating equipment, mining shovels, dragline buckets and the like. The retention assembly of the invention may be used for attaching teeth onto adaptors, for attaching lip shrouds to bucket lips, for installing an adaptor onto a bucket or for similar purposes as known to those skilled in the art. For purposes of describing the invention, the invention will be illustrated with reference to the attachment of a tooth to an adaptor of a work member. However, the invention is not so limited and is to be considered broader in scope than the description of the illustrated embodiment. 
     Referring now to  FIGS. 1-7  and, in particular,  FIG. 1 , retention assembly  10  includes a working member  12  and allows for the removal, installation and retention of tooth  20  to an adaptor  40 . For example, the working member  12  has a plurality of discrete adaptors  40  to which a respective tooth  20  can be retained. For simplification, only one tooth  20  is shown in  FIG. 1 . 
     Referring now to  FIGS. 2 and 3  along with  FIG. 1 , tooth  20  includes an exterior cutting edge  22  to perform the work function of the tooth. Tooth  20  includes an end wall  24  which is constructed and arranged to abut the adaptor  40 . Tooth  20  includes a cavity  26  with tapered walls  28  constructed and arranged to generally mate with corresponding tapered walls of adaptor  40 . An opening  30  is in what will be referred to as the top wall of tooth  20 , although it is understood that due to the symmetry of the tooth  20  and adaptor  40 , tooth  20  may be reversibly installed on adaptor  40  such that the opening  30  may then be considered the bottom wall. Opposite the opening  30  in the bottom interior wall of the tooth  20  is a recess  32  constructed and arranged for receiving fastening receptacle  60 . 
     The adaptor  40  may be separate and apart from the work member  12  or may be integral to work member  12 . The adaptor  40  includes an end portion  42  for slidable insertion with cavity  26  of tooth  20 . The end portion  42  includes tapered walls  44  which are constructed and arranged to mate with the corresponding tapered walls  28  of cavity  26 . It is understood that a preferred embodiment of the general geometry of the tapered walls is shown in the  FIGS. 2 and 3 , although different geometries of taper may be used without departing from the scope of the invention. The geometry of the tapered walls  28  and  44  are such that the tooth  20  may be slidably mounted onto the adaptor  40  to hold the tooth in place with minimal play. However, the tooth is not held so tightly so as to wedge and lock tight in order to preclude the need for removal of the tooth from the adaptor with a hammer or similar implement. Additionally, the tapered faces of the walls  44  of the adaptor prevent the tooth from rotating on the adaptor in any direction and preclude linear movement of the tooth in all directions except the forward direction. In the forward direction, the tooth is constrained by the fastening member  50  as discussed in greater detail hereafter. 
     Additionally, adaptor  40  includes an opening  46  through end portion  42 . The opening is constructed and arranged to align with the opening  30  in tooth  20  and an opening  62  in fastening receptacle  60  to allow passage of fastening means  50  through openings  30 ,  46  and  62 . 
     Fastening receptacle  60  includes a top face  64  which is generally flat and engages the bottom wall  48  of the end portion  42 . There is an opening  62  in this top wall  64  through which fastening member  50  is allowed to pass to engage a fastening member  70 . Fastening receptacle  60  includes a bottom face  66  which is seated in recess  32  of tooth  20 . Receptacle  60  includes an interior wall  68  constructed and arranged to receive the fastening member  70  which in the preferred embodiment is a threaded hexagonal nut. When the fastening member  70  is hexagonal, the interior wall  68  is also hexagonal as shown in  FIG. 5  for receiving and fastening nut  70 . This also prevents rotation of nut  70 . 
     Fastening receptacle  60  may be held in place in recess  32  by a durable polymer resin  72  such as a polyurethane elastomer. In the preferred embodiment, the fastening receptacle is placed into recess  32  in the bottom interior wall of tooth  20  with sufficient clearance on the top and sides so that the polyurethane elastomer can be poured around it and then it hardens so as to encapsulate and hold in place the fastening receptacle  60 . It should be understood that other means may be used to retain fastening receptacle  60  in recess  32  without departing from the scope of the invention. 
     A fastening means  50  is used to secure tooth  20  to adaptor  40 . In the preferred embodiment, the fastening means  50  comprises a bolt having an upper end  52  having a ratchet opening  54  for engagement with a ratchet wrench to install the tooth on the adaptor or to remove the tooth from the adaptor. Fastening means  50  includes a shoulder wall  56  which is seated on corresponding shoulder portion  31  of opening  30  as best shown in  FIG. 3 . This shoulder portion of the bolt will receive a portion of the shock contact when the working member is in use and reduces the stress to the bolt. Fastening means  50  further includes a male threaded portion  58  which engages female threaded portion (not shown) of fastening nut  70 . 
       FIGS. 6 and 7  illustrate another embodiment of the excavation retention assembly invention.  FIG. 6  illustrates the excavation retention assembly as shown in  FIG. 3  as evidenced by like reference numbers. In this embodiment, the pilot end  59  of fastening means  50  differs and a Belleville spring washer  74  is utilized. Specifically, it has been found that when using the assembly shown in  FIGS. 2 and 3 , fastening means  50  may need to be re-tightened during the life of tooth  20 . It has been found that the use of Belleville spring washer  74  will more securely retain fastening means  50  and thereby may preclude the need for tightening fastening means  50  over the life of tooth  20 . While a Belleville spring washer is preferred, it is understood that other washers, such as lock washers, may be used to more securely retain fastening means  50 . In this embodiment Belleville spring washer  74  is positioned between the recess floor  32   a  and fastening nut  70 . It will be seen that the geometry of the pilot end  59  of fastening means  50  is modified to accommodate receipt of Belleville spring washer  74 . Specifically, the end  59   a  includes a reduced diameter to fit through opening  74   a  of the Belleville spring washer. Without being bound to any specific theory, when fastening means  50  is tightened it pushes on Belleville spring washer  74  causing the washer to flatten out. This causes a fastening retaining force over a greater distance than using the fastening means  50  alone. 
     In use, the tooth  20  can be secured to the adaptor  40  by slidably inserting the tooth cavity  26  onto adaptor end  42 . As previously mentioned, the interior walls  28  of cavity  26  are constructed and arranged to generally mate with the tapered walls  44  of adaptor  40  while at the same time not being so tight as to not be removable without a hammer or other implement. When tooth  20  is so engaged with adaptor  40 , the openings  30  in tooth  20 ,  46  in adaptor  40 , and  62  in receptacle  60  are in alignment. Fastening bolt  50  is inserted through these openings and a ratchet wrench is used to tighten bolt  50  into fastening nut  70 . The upward force from the bolt  50  as it is tightened when passing through nut  70  pushes up on receptacle  60  and causes the polymer resin around the receptacle  60  to distort upward against the lower face of adaptor  40  and around and into hole  46  to further secure the tooth to the adaptor. Additionally, when Belleville spring washer  74  is utilized, the tightening of bolt  50  will engage washer  74  pulling it upward to further secure bolt  50  to fastening nut  70 . 
     Although the invention has been described above in relation to preferred embodiments thereof, it will be understood by those skilled in the art that variations and modifications can be effected in these preferred embodiments without departing from the scope and spirit of the invention. For example, while the fastening means and fastening member of a preferred embodiment are engaged by thread means and a ratchet, other securing means may be used without departing from the scope of the invention. Additionally, while a preferred embodiment includes a recess in the tooth for engaging the fastening receptacle, the fastening receptacle may be secured in the tooth by other means without the need for the recess.