Abstract:
A dovetail coupling arrangement is disclosed for securing two removable parts along a coupling axis. The dovetail coupling arrangement includes multiple opposing surfaces between the receiver of a first member and the projection of a second member to provide resistance to forces transmitted in a direction orthogonal to the coupling axis. Such an arrangement may be utilized for jaw sets associated with hydraulic construction, demolition, and scrap handling equipment.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a keyless coupling arrangement for sliding two parts together to form a single unit. 
         [0003]    2. Description of Related Art 
         [0004]    While the discussion hereinafter will make reference to construction equipment, such equipment is also referred to as demolition equipment, scrap handling equipment, and the like. The description of construction equipment is not intended to be restrictive of the equipment being referenced. Demolition equipment, such as heavy-duty metal cutting shears, plate shears, claws, hammers, buckets, grapples, and concrete crushers have been mounted on backhoes powered by hydraulic cylinders for a variety of jobs in the demolition field. This equipment provides for the efficient cutting and handling of scrap. For example, in the dismantling of an industrial building, metal scrap in the form of various diameter pipes, structural I-beams, channels, angles, sheet metal plates, and the like, must be efficiently severed and handled by heavy-duty metal shears. Such metal shears can also be utilized for reducing automobiles, truck frames, railroad cars, and the like. The shears must be able to move and cut the metal scrap pieces regardless of the size or shape of the individual scrap pieces and without any significant damage to the shears. In the demolition of an industrial building, concrete crushing devices, such as a concrete pulverizer or concrete cracker, are also used to reduce the structure to manageable components which can be easily handled and removed from the site. A grapple is often utilized where handling of debris or work pieces is the primary function of the equipment. Historically, all of these pieces of equipment represent distinct tools having significant independent capitol costs. 
         [0005]    Each of these tools utilizes a jaw set pivotal about a pivot axis. Each of these jaw sets may be subjected to forces developed or generated on the magnitude of between less than 1 ton to more than 10,000 tons and, as a result, it is imperative that each of the jaws in the jaw set is fabricated, shaped, or cast to withstand such forces. However, certain jaw set designs may preferably require a portion of the jaw set to be disassembled in order to capture the pivot shaft between the lower jaw and the upper jaw. In the past, such a coupling arrangement was achieved by sliding the hub into the anvil and then inserting removable keys along the direction of insertion/removal to secure the anvil and the hub relative to one another. While this adequately secured the hub within the anvil, it is a relatively labor intense practice and, furthermore, the stress forces produced by this coupling tend to be concentrated within the keys such that there is not an equal stress distribution over the anvil and the hub. 
         [0006]    A design is needed to slideably secure a hub within an anvil, whereby the design is relatively simple but, at the same time, eliminates the need for keys and provides effective redistribution of the stresses, such that localized forces are reduced and the stresses overall are more evenly distributed among the unified hub/anvil. 
       SUMMARY OF THE INVENTION 
       [0007]    One embodiment of the invention is directed to a dovetail coupling arrangement for securing two removable parts along a coupling axis which are supporting segments of a shaft having a shaft axis. The coupling arrangement is suited to resist translational forces orthogonal to the coupling axis and has a first part having a receiver extending along the coupling axis, wherein the coupling axis is parallel to the shaft axis and, wherein the receiver has an inner wall with a receiver wall. The arrangement also has a second part with a projection extending along the coupling axis and an outer wall with a projection wall profile. A substantial portion of the outer wall of the projection corresponds to the inner wall of receiver, such that the projection mates with the receiver with a slip fit. The receiver and the projection define mating interlocking walls along the coupling axis to restrict movement of the projection within the receiver along directions orthogonal to the coupling axis. 
         [0008]    A second embodiment of the invention is directed to a dovetail coupling arrangement for securing two removable parts along a coupling axis, wherein the coupling arrangement is suited to resist translational forces orthogonal to the longitudinal axis. The arrangement has a first part with a receiver extending along the coupling axis, wherein the receiver has an inner wall with a receiver wall. The arrangement also has a second part with a projection extending along the coupling axis and an outer wall with a projection wall. A substantial portion of the outer wall of the projection corresponds to the inner wall of receiver such that the projection mates with the receiver with a slip fit. The receiver and the projection define mating interlocking walls along the coupling axis to restrict movement of the projection within the receiver along directions orthogonal to the coupling axis. A removable shaft extends within the first part and the second part. The shaft is oriented in a direction generally orthogonal to the longitudinal axis to prevent relative movement between the first part and the second part along the coupling axis. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a hydraulically operated jaw utilizing a hub and anvil in accordance with the subject invention; 
           [0010]      FIG. 2  is an exploded perspective view of the hub and anvil in accordance with the subject invention; 
           [0011]      FIG. 3  is a different exploded perspective view of the hub and anvil in accordance with the subject invention; 
           [0012]      FIG. 4A  is a view of a section of the anvil along arrows  4 A- 4 A in  FIG. 2 ; 
           [0013]      FIG. 4B  is a cross-section view of the hub along arrows  4 B- 4 B in  FIG. 2 ; 
           [0014]      FIG. 5  is an exploded perspective view similar to  FIG. 2  but with securement bolts included; 
           [0015]      FIG. 6  is an exploded perspective view similar to  FIG. 3  but with securement bolts included; 
           [0016]      FIG. 7A  is a view of a section of the anvil along arrows  7 A- 7 A in  FIG. 5 ; 
           [0017]      FIG. 7B  is a cross-section view of the hub along arrows  7 B- 7 B in  FIG. 5 ; 
           [0018]      FIG. 8A  is an exploded cross-sectional view of the assembled hub/anvil along the plane defined by arrows  8 A- 8 A in  FIG. 5 ; and 
           [0019]      FIG. 8B  is an assembled view of the arrangement illustrated in  FIG. 8A . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    For purposes of explaining the subject invention, an attachment  5  used for demolition may be associated with a hydraulic excavator (not shown) and includes a pair of movable jaws  10 ,  11  which pivot about a main shaft  15 . In operation of the embodiment illustrated in  FIG. 1 , the jaw  11  and the jaw  10  pivot toward one another, such that the tip  13  of jaw  11  passes through the opening  14  of jaw  10 . 
         [0021]    Jaw  11  includes a jaw portion  17  having a bore extending therethrough, which pivots about the main shaft  15 . Furthermore, jaw  10  includes a jaw portion  19  and a jaw portion  21  which also have a bore (not shown) extending therethrough pivoting about the main shaft  15 . 
         [0022]    Generally speaking, the main shaft  15  and the jaw  10  and jaw  11  pivoting thereabout define a jaw set  23 . 
         [0023]      FIG. 1  illustrates a heavy-duty metal cutting shear, whereby the jaw set  23  is made up of a jaw  11 , which has a tip  13  that passes through the opening  14  of jaw  10  when the jaws  10 ,  11  are closed. While this is one type of jaw set  23 , it should be appreciated that other jaw sets exist, and the subject invention may be applied to these jaw sets as well. In particular, the subject invention may be applied to jaw sets associated with concrete crushers, where the two opposing jaws have tips that abut with one another when the jaws come together or associated with grapples, which have two opposing jaws, each with tines that interlock with one another when the jaws come together. Overall, any discussion of jaw sets should not be limited to the functions of a particular jaw set, but should focus upon the arrangement by which the two opposing jaws are connected. 
         [0024]    In order to assemble or disassemble the jaw set  23 , it may preferably be necessary to disassemble the jaw  10 . In particular, the jaw  10  is comprised of an anvil  25  and a hub  30  that is secured within the anvil  25 . It is this coupling arrangement between the anvil  25  and the hub  30  to which the subject invention is directed. 
         [0025]    Although the following discussion will be directed to the hub  30  secured within the anvil  25  in the context of a jaw set  23  associated with demolition equipment  5 , it should be appreciated that this coupling arrangement has a wide range of applications and, therefore, should not be limited to the particular application discussed herein. 
         [0026]      FIGS. 2 and 3  illustrate exploded views of the hub  30  relative to the anvil  25 , which are shown in their assembled state in  FIG. 1 . 
         [0027]    For ease in understanding this configuration,  FIGS. 2 ,  3 ,  4 A, and  4 B will be discussed together. 
         [0028]    As mentioned, the subject invention is directed to a coupling arrangement for removably securing the hub  30  within the anvil  25 . At least with respect to this arrangement, the hub  30  has a bore  32  extending therethrough and the anvil  25  has a bore  27  extending therethrough along a shaft axis  35 . The hub  30  slides within the anvil  25  along a coupling axis  40 . The coupling arrangement is suited to resist translational forces orthogonal to the coupling axis  40 . 
         [0029]    The anvil  25  has a receiver  45  extending along the coupling axis  40 . As illustrated in  FIGS. 2 and 3 , the coupling axis  40  may be parallel to the shaft axis  35 . The receiver  45  has an inner wall  47  with a receiver wall profile. The hub  30  has a projection  50  extending along the coupling axis  40  and an outer wall  52  with a projection wall profile. A substantial portion of the outer wall  52  of the projection  50  corresponds to the inner wall  47  of the receiver  45 , such that the projection  50  mates with the receiver  45  with a slip fit. The receiver profile and the projection profile define mating interlocking walls  47 ,  52  along the coupling axis  40  to restrict movement of the projection  50  within the receiver  45  along directions orthogonal to the coupling axis  40 . 
         [0030]    Directing attention to  FIGS. 4A and 4B , when viewed along the coupling axis  40  from the end of the projection  50  (along arrows  4 B- 4 B), the profile of the projection  50  has a dovetail shape ( FIG. 4B ) with a bottom outer surface  54  and a primary outer top surface  56 . The bottom outer surface  54  and the primary top outer surface  56  are connected by opposing outer angled walls  58 ,  60 . On the other hand, the receiver  45  has an open section  62  with an inner bottom surface  64  and opposed inner angled walls  66 ,  68  extending upwardly therefrom, such that when the anvil  25  and the hub  30  are mated, the bottom outer surface  54  and the outer angled walls  58 ,  60  of the projection  50  are engaged with the inner bottom surface  64  and the inner angled walls  66 ,  68  of the receiver  45 . 
         [0031]    As seen from an inspection of  FIGS. 4A and 4B , the outer angled walls  58 ,  60  of the projection  50  and the inner angled walls  66 ,  68  of the receiver  45  extend upwardly and inwardly at a dovetail angle X of between 40 and 70 degrees, with respect to a line  70 . The line  70  extends perpendicular to the outer bottom surface  54  of the projection  50  and the inner bottom surface  64  of the receiver  45 . In a preferred embodiment, the dovetail angle X is approximately 57 degrees. 
         [0032]    The receiver  45 , in a region adjacent to the open section  62 , further includes a primary enclosed section  75  formed with the inner bottom surface  64  and the opposing inner angled walls  66 ,  68  common with the open sections  62  and, additionally, includes a primary inner top surface  77  connecting the inner angled walls  66 ,  68 , thereby mating the anvil  25  with the hub  30 . Additionally, the primary outer top surface  56  of the projection  50  is engaged with the primary inner top surface  77  of the receiver  45 . 
         [0033]    As illustrated in  FIGS. 2 ,  3 ,  4 A, and  4 B, the receiver  45  further includes, along at least a portion of depth of the receiver  45 , a secondary enclosed section  80  formed by the inner bottom surface  64  and the inner opposing angled walls  66 ,  68  with the open section  62  and additionally includes opposing inner extension walls  83 ,  85  extending from the dovetail shape of the receiver  45  and connected by a secondary inner top surface  87 . The profile of the projection  50  further includes matching opposing outer extension walls  90 ,  92  extending upwardly from the dovetail shape of the projection  50  and connected by a secondary outer top surface  94 , such that when the anvil  25  and the hub  30  are mated, the opposing inner extension walls  83 ,  85  and the secondary inner top surface  87  of the receiver  50  mate with the opposing outer extension walls  90 ,  92  and the second outer top surface  94  of the projection  50 . 
         [0034]    The open section  62  of the receiver  45  may further include inner horizontal segments  97 ,  99  extending from the dovetail shape and, wherein the projection  50  further includes outer horizontal segments  100 ,  102  extending from the outer dovetail shape of the projection, such that when the anvil  25  is mated with the hub  30 , the inner horizontal surface  97  and inner horizontal surface  99  rest upon the outer horizontal surface  100 ,  102 , respectively. 
         [0035]    As illustrated in  FIGS. 4A and 4B , the multitude of inner surfaces associated with the receiver  45  and outer surfaces associated with the projection are connected to adjacent surfaces with transition segments that are curved to eliminate sharp edges that may increase stress concentrations. 
         [0036]    So far discussed have been the surfaces between the receiver  45  and the projection  50  that prevent translation in a direction orthogonal to the coupling axis  40 . However, it is also necessary to restrain the hub  30 , with respect to the anvil  25 , in the direction of the coupling axis  40 , even though the primary force is experienced by the anvil/hub assembly will be in a direction different than that of the coupling axis  40 . 
         [0037]    Directing attention to  FIGS. 5 ,  6 ,  7 A, and  7 B, to secure the hub  30  within the anvil  25  along the coupling axis  40 , one or more bolts  105   a ,  105   b ,  105   c  extend through the inner bottom surface  64  through bores  107   a ,  107   b ,  107   c  and into matching bores  109   a ,  109   b ,  109   c , which are threaded, extending into the outer bottom surface  54  of the hub  30  to secure the hub  30  within the anvil  25  along the coupling axis  40 . As illustrated in  FIG. 5 , the bolt  105   a  may further include a sleeve  110   a  which extends through the bore  107   a  of the anvil  25  and into an enlarged diameter portion of the bore  109   a  of the hub  30  so that any shear loads produced between the hub  30  and the anvil  25  will be absorbed by the sleeve  110   a , which has a greater cross-sectional area than the bolt  105   a  associated therewith. The bore  109   a  has an enlarged diameter portion  112   a  adjacent to the outer bottom surface  54  to accommodate the sleeve  110   a . This enlarged diameter is not threaded. The threaded portion of the bore  109   a  begins beyond the enlarged diameter portion  112   a . In addition to providing additional cross-sectional area to absorb shear forces, the sleeve  110   a  is also used to properly align the hub  30  within the anvil  25  prior to securing the bolts  105   a ,  105   b ,  105   c  within their respective bores  109   a ,  109   b ,  109   c . Once secured within their respective bores, the bolts  105   b ,  105   c  and the sleeve  110   a  absorb shear forces but, furthermore, the bolts  105   a ,  105   b ,  105   c  retain the outer bottom surface  54  of hub  30  against the inner bottom surface  64  of the anvil  25  to minimize any twisting of the hub  30  within the anvil  25 . 
         [0038]    Additionally, to secure the hub  30  within the anvil  25 , bolts  116   a ,  116   b ,  116   c ,  116   d  extend through bores  117   a ,  117   b ,  117   c ,  117   d  within the anvil  25  and into threaded bores  118   a ,  118   b ,  118   c ,  118   d  within the hub  30 . Sleeves  121   a ,  121   b , associated with bolts  116   a ,  116   b , fit within enlarged diameter portions  122   a ,  122   b  extending inwardly into the threaded bores  118   a ,  118   b  and with bolts  116   c  and  116   d  to provide additional cross-sectional area to resist shear forces in a direction perpendicular to the coupling axis  40 . Furthermore, all of the bolts  116   a ,  116   b ,  116   c ,  116   d  pull the front wall  119  of the hub  30  against the back wall  123  of the receiver  45  to provide additional stability to the projection  50 /receiver  45  coupling. 
         [0039]    In order to disassemble the hub  30  from the anvil  25 , it is necessary to push the projection  50  of the hub  30  from the receiver  45  of the anvil  25 . To achieve this, an ejection bolt  114  ( FIGS. 5 ,  8 A,  8 B) extends through a threaded bore  115  through the back wall  123  of the receiver  45 . The threaded bore  115  is aligned with the front wall  119  of the projection  50 . With all of the bolts  105   a ,  105   b ,  105   c ,  116   a ,  116   b ,  116   c ,  116   d  and all of the sleeves  110   a ,  121   a ,  121   b  removed from their respective bores, the ejection bolt  114  may be advanced within the threaded bore  115  against the front wall  119  of the projection  30  to urge the projection  50  from the receiver  45 , thereby separating the hub  30  from the anvil  25 . 
         [0040]    As mentioned, the projection  50  has a front wall  119  and the receiver has a back wall  123 , wherein the receiver back wall  123  and the projection front wall  119  face one another. While what has been described is the ejection bolt  114  acting against the front wall  119  of the projection  50 , it is entirely possible for the ejection bolt  114  to extend through the hub and act upon the back wall  123  of the receiver  45 . 
         [0041]    The embodiments so far discussed are directed to a single hub  30  with a projection  50 . The projection  50  is mounted within a receiver  45  of an anvil. It should be understood that more than one hub may be mounted to a single anvil. As an example, and directing attention to  FIG. 5 , it is possible to form an additional receiver on the opposite side of the anvil  25  to accept a projection  50  on the opposite side of the anvil  25 . Under the circumstances, more than one hub may be mounted upon a single anvil. 
         [0042]    While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. The presently preferred embodiments described herein are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.