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CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority from and hereby expressly incorporates by reference U.S. provisional application No. 60/286,513 filed Apr. 26, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates generally to couplers used to connect implements such as buckets, grapples, shears and the like to a “dipper stick” or arm of an excavator, backhoe, tractor or other prime mover. More particularly, the present invention relates to an improved structure for such a coupler that is more efficient to manufacture in terms of time and materials without sacrificing strength. The method of manufacturing the subject coupler also forms a part of the present invention.  
           [0003]    Couplers of the type described above are well-known and in widespread use. One common coupler is available commercially from JRB Company, Inc., Akron, Ohio, U.S.A., and is sold under the registered trademarks SLIDE-LOC® and SMART-LOC™. Notwithstanding the commercial success of the SLIDE-LOC® and SMART-LOC™ couplers, it has been deemed desirable to develop an improved coupler that is more efficient to manufacture and that includes a more open central region that facilitates mounting of a fluid cylinder and other components to the coupler as required.  
         SUMMARY OF THE INVENTION  
         [0004]    In accordance with a first aspect of the present development, a method for constructing a coupler comprises securing a first upper bearing plate to a first female rib member and securing a second upper bearing plate to a second female rib member. The first and second female rib members each define first and second spaced-apart recesses adapted to receive first and second pins of an implement. The first and second female rib members are arranged in spaced-apart relation with the first and second bearing plates aligned and spaced-apart from each other, the first recesses aligned with each other to define a first pin-receiving hook and the second recesses aligned with each other to define a second pin-receiving hook. A lower bearing plate is positioned between said first and second female rib members and is spaced from the first and second upper bearing plates whereby a slot is defined between the lower bearing plate and the first and second upper bearing plates. At least one cross member is positioned between the first and second female rib members. This cross member is secured to both the first and second female rib members. The lower bearing plate is secured to both the first and second female rib members. A first outer rib member is connected and secured to the first female rib member to define a first rib assembly and a second outer rib member is connected and secured to the second female rib member to define a second rib assembly. The first and second outer rib members each define first and second spaced apart pin openings, and the first pin openings are aligned with each other and the second pin openings are aligned with each other. A lock member is slidably positioned in the space defined between the upper bearing plate and the lower bearing plate. An actuator is secured in a space located between the first and second rib assemblies. The actuator is operably connected to the lock member whereby the actuator is adapted to move the lock member between a retracted position and an extended position. The lock member extends at least partially into the second pin-receiving hook when in the extended position.  
           [0005]    In accordance with another aspect of the present development, a coupler formed in accordance with the foregoing method is provided.  
           [0006]    In accordance with a further aspect of the present development, a coupler includes first and second laterally spaced-apart rib assemblies defining a space therebetween and each comprising first and second pin-openings. The first openings of the first and second rib assemblies are aligned with each other and the second openings of the first and second rib assemblies are aligned with each other. A plurality of cross-members extend between and interconnect the first and second rib assemblies. A first upper bearing plate is connected to the first rib assembly and a second upper bearing plate connected to the second rib assembly. A lower bearing plate is connected to both the first and second rib assemblies and is spaced from the first and second upper bearing plates so that a slot is defined between the lower bearing plate and the first and second upper bearing plates. At least one of the first and second upper bearing plates and the lower bearing plate includes a tab projecting outwardly therefrom that is inserted into a corresponding tab-opening defined in one of the first and second rib assemblies. A lock member is slidably positioned in the slot, and an actuator is located in the space between said first and second rib assemblies. The actuator is operably coupled to the lock member for moving the lock member between first and second operative positions.  
           [0007]    One advantage of the present invention resides in the provision of a novel and unobvious coupler and method for manufacturing same.  
           [0008]    Another advantage of the present invention is found in the provision of a coupler that allows for a rear-mounted fluid cylinder or other actuation means that extends and retracts a locking plate.  
           [0009]    A further advantage of the present invention resides in the provision of a coupler that is lighter weight that conventional couplers of comparable size without sacrificing strength and durability.  
           [0010]    Still another advantage of the present invention is the provision of a coupler wherein machining and welding are minimized to reduce assembly time and expense.  
           [0011]    A still further advantage of the present invention resides in the provision of a method for manufacturing a coupler that is highly efficient in that it facilitates improved material flow and minimizes set-up and staging of sub-assemblies of the coupler.  
           [0012]    A further advantage of the present invention resides in the provision of a coupler wherein open space is provided to facilitate self-cleaning of mud and other debris from the coupler body.  
           [0013]    A still further advantage of the present invention is found in the provision of a manufacturing method for a coupler that does not require use of a jig to hold the coupler components during assembly.  
           [0014]    Still other benefits and advantages of the present invention will become apparent to those of ordinary skill in the art to which the invention pertains upon reading the present specification. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    The invention comprises various components and arrangements of components, and various steps and arrangements of steps, preferred embodiments of which are described herein and illustrated in the accompanying drawings that form a part hereof and wherein:  
         [0016]    [0016]FIG. 1 is an isometric view of a coupler formed in accordance with the present invention;  
         [0017]    [0017]FIG. 2 is another isometric view of the coupler of FIG. 1;  
         [0018]    [0018]FIG. 3 is a side elevational view of the coupler shown in FIG. 1;  
         [0019]    [0019]FIG. 4 is a top plan view of the coupler shown in FIG. 1;  
         [0020]    [0020]FIG. 5 is similar to FIG. 1 but shows the coupler of FIG. 1 with one of the lateral rib assemblies removed to reveal additional components of the coupler; and,  
         [0021]    [0021]FIG. 6 illustrates one of the lateral rib assemblies used to form the coupler of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0022]    Referring now to the drawings, wherein the showings are for purposes of illustrating a preferred embodiment only and not for purposes of limiting the invention in any way, a coupler C formed in accordance with the present invention is shown in FIGS. 1 and 2. The coupler C comprises first and second lateral rib assemblies R 1 ,R 2  that are preferably mirror images of each other. The rib assemblies R 1 ,R 2  preferably respectively comprise a female rib FR 1 ,FR 2  and an outer rib OR 1 ,OR 2  fixedly secured to the female rib by welding or other suitable and convenient means (see also FIG. 6).  
         [0023]    The rib assembly R 1  is illustrated alone in FIG. 6 and clearly shows the structure of the female and outer rib members FR 1 ,OR 1 . Although not shown in FIG. 6, the rib assembly R 2  is a mirror image of the rib assembly R 1 . Referring to FIGS. 1, 2 and  6 , the female rib members FR 1 ,FR 2  are cut from suitable steel plate material and each define a first or rear open U-shaped recess  10  and a second or front open U-shaped recess  12 . The female rib members FR 1 ,FR 2  each further define a utility aperture  14  at a forward end  16 . Intermediate the rear and front recesses  10 , 12 , the female rib members FR 1 ,FR 2  define multiple tab-receiving openings, preferably three opening  20 , 22 , 24  as illustrated herein. Finally, the female rib members FR 1 ,FR 2  define first and second spaced-apart dowel openings  26 , 28 .  
         [0024]    With continuing reference to FIGS. 1, 2 and  6 , the outer rib members OR 1 ,OR 2  are also mirror images of each other and are cut from suitable steel plate material and define first and second spaced-apart pin openings  30 , 32 . Also, the outer rib members OR 1 ,OR 2  define first and second preferably identical dowel openings that align respectively with the dowel openings  26 , 28  defined by the female rib members FR 1 ,FR 2  (only the first of the first and second dowel openings of the outer ribs members OR 1 ,OR 2  is visible in the FIGURES and is referenced at  38  in FIG. 1). The location of the second dowel opening will become readily apparent to those of ordinary skill in the art upon a complete reading of the present disclosure.  
         [0025]    The rib assemblies R 1 ,R 2  are arranged in spaced-apart parallel relation to each other and are aligned with each other so that the rear recesses  10 , the front recesses  12 , the first pin openings  30  and the second pin openings  32  of the rib assemblies R 1 ,R 2  are in respective alignment or registry. As shown in FIG. 3, the rear recesses  10  are registered on a common transverse axis L 1  and the front recesses are registered on a common transverse axis L 2 . Thus, the rear recesses  10  together define a rear pin-receiving region  40 , referred to herein as a rear “hook”  40 , and the front recesses  12  together define a front pin-receiving region  42 , referred to herein as a front “hook”  42 . The front and rear hooks  40 , 42  open in different directions as is generally known. Likewise, the pin openings  30  are registered on a common transverse axis L 3  and the pin openings  32  are registered on a common transverse axis L 4 . These axes L 1 -L 4  are parallel (within acceptable design and manufacturing tolerances) to first and second parallel spaced-apart pins (not shown) connected to a bucket or other associated implement to be picked-up by the coupler C. More specifically, the first and second parallel spaced-apart pins of the associated implement are received respectively in the rear and front hooks  40 , 42 . As is generally known, the arrangement of the hooks  40 , 42  so that they open in different directions as shown requires that, when attaching the associated bucket or other implement to the coupler C, the first pin of the associated implement must be seated in the rear hook  40  before the second pin of the associated implement can be seated in the front hook  42 . Decoupling is accomplished in the reverse order. The coupler C, itself, is connected to an arm or dipper stick and a control link of an excavator or other prime mover by a conventional pin-on connection using the aligned pin openings  30 ,  32 , respectively. It is also preferred that the utility apertures  14  of the respective rib assemblies R 1 ,R 2  be registered with each other as shown in FIG. 3. These utility apertures provide a convenient location for connection of a chain, hook or other item to the coupler C as required for lifting, dragging or other operations.  
         [0026]    Various members extend between and interconnect the rib assemblies R 1 ,R 2 . A main cross-member  50  is defined as a rectangular steel member and is welded at its opposite ends to the rib assemblies R 1 ,R 2  to set the distance between the rib assemblies. A shield plate  52  is welded between the rib assemblies R 1 ,R 2  between the utility apertures  14  and the front recesses  12 . As shown, the shield plate  52  preferably substantially isolates the forward tips  16  from the remainder of the coupler C to inhibit dirt and debris from flowing into the space between the rib assemblies R 1 ,R 2 .  
         [0027]    As best seen in FIGS. 3 and 4, a plurality of cross-members extend between the rib assemblies R 1 ,R 2  adjacent the rear hook (pin-receiving area)  40 . In particular, a main rear hook plate  60  is located so that an inner surface thereof  62  lies flush or even with a first or lower linear side portion of each of the recesses  10  defining the rear hook  40 . For added strength, the main rear hook plate  60  extends inwardly away from the rear hook  40  so that in innermost end  64  thereof extends toward a central region of the coupler C partway between the rear and front hooks  40 , 42 . As may be seen clearly in FIG. 4, the main rear hook plate  60  defines a large opening  66  that helps to prevent collection of dirt and other debris in the rear pin-receiving area  40 , i.e., dirt and debris exit the rear hook  40  through the opening  66 . Second and third rear hook plates  68 , 70  also extend between and interconnect the rib assemblies R 1 ,R 2  adjacent the rear hook  40  (the third hook plate is not shown in FIG. 5 for clarity). The second rear hook plate  68  is preferably located generally opposite the first rear hook plate  60  so that an inner surface  69  thereof is approximately flush with a second or upper linear side surface of each of the recesses  10  defining the rear hook  40 . The second rear hook plate  68  can be moved toward and away from the first rear hook plate  60  a minimal amount during construction of the coupler C to adjust the tolerance of the rear hook  40 . Specifically, the second rear hook plate  68  is located to ensure that the rear hook  40  is conformed to receive the first pin of the bucket or other associated implement tightly with minimal play or slop. Thus, the inner surface  69  of the second rear hook plate  68  is not necessarily flush with the upper linear side surfaces of the aligned recesses  10 . The third rear hook plate  70  is located between the first and second rear hook plates  60 , 68  so that its inner surface  71  is located generally tangential with the curved innermost end of the aligned recesses  10  defining the rear hook  40 . Those of ordinary skill in the art will recognize that the inner surfaces  62 , 69 , 71  of the rear hook plates  60 , 68 , 70  generally approximate the general shape of the U-shaped recesses  10  that define the rear hook  40 . These plates  60 , 68 , 70  increase the wear surface area for the first pin of an associated bucket or other implement that is received in the rear hook  40  so that all loads and wear are not concentrated directly in the aligned recesses  10 . Also, the second and third rear hook plates  68 , 70  are preferable rectangular in cross-section as shown herein.  
         [0028]    With continuing reference to FIG. 3, a front hook plate  80  (not shown in FIG. 5 for clarity) extends between and interconnects the rib assemblies R 1 ,R 2  adjacent the front hook  42 . Preferably the front hook plate  80  is rectangular in cross-section and includes an inner surface  82  that lies generally tangential to an innermost curved end of the recesses  12  defining the front hook  42 . The front hook plate  80  increases the wear surface area for the second pin of an associated bucket or other implement that is received in the recess  42 .  
         [0029]    With reference primarily to FIGS.  4 - 6 , a first upper bearing plate  90  is fixedly secured to the first rib assembly R 1 . More particularly, the first upper bearing plate  90  defines first and second tabs that are received respectively in the tab-receiving openings  20 , 22 . When the tabs of the first upper bearing plate  90  are inserted into the openings  20 , 22 , the first upper bearing plate  90  is properly located relative to the first rib assembly R 1 . Of course, the first upper bearing plate  90  is welded in position once the tabs thereof are inserted into the tab-receiving openings  20 , 22  of the first rib assembly R 1 . A second upper bearing plate  94  is a mirror image of the first upper bearing plate  90 . It is fixedly secured to the second rib assembly R 2  directly opposite the first upper bearing plate  90 . As may be seen in FIGS. 3 and 5, the second upper bearing plate  94  includes first and second spaced-apart tabs  95   a,   95   b  that are received respectively in the openings  20 , 22  defined in the second rib assembly R 2 . The tabs  95   a,   95   b  are identical to the tabs found on the first upper bearing plate  90  that are not visible in the FIGURES. The first and second upper bearing plates  90 , 94  are spaced-apart from each other so that a gap is located therebetween.  
         [0030]    A lower bearing plate  100  extends between and is fixedly secured to both rib assemblies R 1 ,R 2 . The lower bearing plate  100  includes tabs  102  projecting from its opposite lateral sides. One of the tabs  102  is visible in FIG. 5, and the other tab (not shown) is identical to the tab  102  visible in FIG. 5 and located directly opposite from the tab  102 . The lower bearing plate  100  is spaced apart from the first and second upper bearing plates  90 , 94  so that a slot  105  is defined between the two upper bearing plates  90 , 94  and the lower bearing plate  100 . It is important to note that no machining or other metal working is required to form the slot  105 .  
         [0031]    A lock member  120  such as the illustrated wedge is slidably located in the slot  105 . The lock member  120  is adapted for sliding movement as indicated by the arrow A 1  in FIG. 3. In particular, at one extreme, the lock member  120  is movable to an extended position, as shown in FIG. 3, wherein it projects into the front hook/pin-receiving area  42 . In this extended position, the lock member  120  traps or captures a pin of an associated bucket or other implement in the front hook  42 . The lock member  120  is selectably movable from the extended position to a retracted position as shown in FIGS. 1 and 5. In this retracted position, the lock member  120  is moved completely out of the front hook  42  and does not interfere with placement of a pin in or removal of a pin from the front hook  42  as required to attach/detach an associated implement to the coupler C. To allow use of a single-width lock member  120  for multiple size couplers, shims  122  (FIG. 5) are located on one or both lateral sides of the lock member  120  as needed to eliminate undesired space between the lock member  120  and the rib assemblies R 1 ,R 2 .  
         [0032]    The lock member  120  can be moved manually or by fluid-power or electro-mechanical means, e.g., by a lever, a ball-screw, a fluid-cylinder, a solenoid, or other suitable and convenient actuation means. In the preferred embodiment, a fluid cylinder such as a hydraulic cylinder  130  (FIG. 5) is located between the rib assemblies R 1 ,R 2  and operably coupled to the lock member  120  to move the lock member  120  between the extended and retracted positions. Alternatively, electro-mechanical means such as a solenoid can be employed. The fluid cylinder  130  includes a piston  132  that is secured to the lock member  120  by a lug  134  as shown in FIGS. 4 and 5.  
         [0033]    The fluid cylinder  130  is secured between the rib assemblies R 1 ,R 2  by a rear-mounting arrangement that minimizes stress on the cylinder  130 , itself. Specifically, first and second bosses  140 , 142  are respectively fixedly secured in bores  143   a,   143   b  (see FIG. 4) defined in the rib assemblies R 1 ,R 2 , and a load-pin or cross-pin  150  is secured between the bosses  140 , 142 . As shown in FIG. 4, a first bore  152  extends entirely through the first boss  140 , and a second bore  154  extends entirely through the second boss  142 . The first and second bores  152 , 154  are aligned. As shown in FIG. 5, the cylinder  130  includes a mounting base  136  that defines a through-bore that is aligned with the bores  152 , 154 . To secure the cylinder  130  in its operative position, the cross-pin  150  is slidably received in the aligned bores  152 , 154  and through the bore defined in the cylinder mounting base  136 . Although the cross-pin  150  could be welded in position, it is preferably temporarily secured in the bores  152 , 154  by conventional pin holders that are secured to the outer faces of the rib assemblies R 1 ,R 2  as shown. Use of a removable cross-pin  150  facilitates repair and replacement of the cylinder  130 , i.e., the cylinder  130  is easily removed by removal of the pin  150 . Most preferably, the pin  150  is defined from a high strength corrosion resistant metal such as 17-4 precipitation hardening (PH) stainless steel or the like that does not corrode, is not brittle, is very strong and does not work-soften.  
         [0034]    To construct the coupler C, no form or “jig” is required. However, it is preferred that first and second spaced apart parallel pins be provided that simulate the first and second pins of an associated implement so that these pins can be received respectively in the rear and front hooks  40 , 42  during construction of the coupler C to facilitate alignment of the rib assemblies R 1 ,R 2  with each other. In an initial step, the first upper bearing plate  90  is temporarily secured by tack welding to the first female rib member FR 1 , with the tabs of the upper bearing plate  90  received in the tab-receiving openings  20 , 22  of the female rib member FR 1  to ensure proper and convenient location of the first upper bearing plate  90 . The two female rib members FR 1 ,FR 2  are then connected in a registered, parallel, spaced-apart manner to the associated first and second spaced apart parallel pins that are used to simulate the pins of an associated implement so that a first one of the pins is received in the aligned recesses  10  and the second one of the pins is received in the aligned recesses  12  of the female rib members FR 1 ,FR 2 . The aligned first recesses  10  cooperate to define a first pin-receiving hook H 1  and the aligned second recesses cooperate to define a second pin-receiving hook H 2  (FIG. 1).  
         [0035]    The tabs  95   a,   95   b  of the second upper bearing plate  94  are inserted into the openings  20 , 22  of the second female rib member FR 2 . The lock member  120 , itself, or a similar block member is inserted beneath the first and second upper bearing plates  90 , 94  and used to align the second upper bearing plate  94  with the first upper bearing plate  90  so that the plates  90 , 94  are directly opposed from one another (the tabs  95   a,   95   b  fit loosely in the openings  20 , 22  to allow for this limited adjustment). Once the second upper bearing plate  94  it is aligned with the first upper bearing plate  90 , the second upper bearing plate  94  is also tack welded into position. The lower bearing plate  100  is then placed in position (but not welded at this stage) with its opposed tabs  102  respectively located in the tab-receiving openings  24  of the female rib members FR 1 ,FR 2 .  
         [0036]    The main cross-member  50  is tack welded between the first and second female members FR 1 ,FR 2  to set the spacing between the first and second female rib members FR 1 ,FR 2 . The lower bearing plate  100  is then tack welded into position. The remaining cross-members such as the shield plate  52 , the rear hook plates  60 , 68 , 70 , and the front hook plate  80  are then tack welded into position.  
         [0037]    The outer ribs OR 1 ,OR 2  are then temporarily secured to the female ribs FR 1 ,FR 2 , respectively. With reference to FIG. 6, the first and second dowel openings  26 , 28  of the female rib member FR 1  are aligned respectively with first and second dowel openings  36 , 38  defined in the first outer rib member OR 1  and dowels (not shown) are inserted through and closely received in these aligned openings to temporarily fix the first female rib member FR 1  to the first outer rib member OR 1 . These members are then tack welded together. The second female rib member FR 2  and second outer rib member OR 2  are secured in the same manner. FIG. 1 shows one of the dowel openings  38  defined in the second outer rib member OR 2  (the other dowel opening was located where the cross-pin  150  is now shown, coaxial with the cross-pin).  
         [0038]    At this stage, all members noted above that have been tack welded together are permanently fixedly secured to each other by welding. Next, machining is carried out to machine the pin openings  30 , 32  to ensure their proper dimensions and smoothness or finish. Machining is also carried out to define the aligned openings  143   a,   143   b  through the rib assemblies R 1 ,R 2  that receive the cross-pin bosses  140 , 142 . More particularly, machining of these bores is carried out coaxial with the dowel openings  26  and the aligned dowel openings defined in the outer rib members OR 1 ,OR 2 . No further machining is required and this provides a critical advantage relative to conventional couplers.  
         [0039]    The bosses  140 , 142  are welded into position. Also, pin holders  160 , 162  are welded to an outer face of the second outer rib member OR 2  coaxial with the pin openings  30 , 32 , respectively. As is generally well known, the pin holders are used to retain the pins by which the coupler C is operably secured to an arm or dipper stick by a pin-on connection.  
         [0040]    The lock member  120  is positioned in the slot  105  (if not already so positioned) and the actuator such as the fluid cylinder  130  is secured in the space defined between the two rib assemblies R 1 ,R 2  as described above, i.e., by inserting the cross-pin  150  through a bore defined in the mounting base  136  of the cylinder  130 . The actuator is operably connected to the lock member  120 . In the illustrated example, this requires that the piston  132  of the fluid cylinder  130  be operably coupled to the lock member  120  via lug  134 .  
         [0041]    By way of example only, the rib assemblies R 1 ,R 2  and other components of the coupler C can be constructed from steel plate commonly referred to in the trade as T1 or A514 steel. Components that must be wear resistant, such as the hook plates  60 , 68 , 70 , 80  and the lock member  120  are preferably defined from AR400 steel plate or another suitable abrasion resistant steel or other metal. Of course, other metals and other materials can be used in the alternative, and the invention is not to be construed as being limited to use of any particular materials to construct the coupler C.  
         [0042]    Modifications and alterations will occur to those of ordinary skill in the art to which the invention pertains upon reading and understanding this specification. It is intended that the invention be construed as including and/or encompassing all such modifications and alterations.

Summary:
A quick-coupler for operably connecting a bucket or other implement to the arm or dipper-stick of an excavator, backhoe and/or other machine includes a first and second laterally spaced-apart rib assemblies. A first upper bearing plate is connected to the first rib assembly and a second upper bearing plate connected to the second rib assembly. A lower bearing plate is connected to both the first and second rib assemblies and is spaced from the first and second upper bearing plates so that a slot is defined between the lower bearing plate and the first and second upper bearing plates. At least one of the first and second upper bearing plates and the lower bearing plate includes a tab projecting outwardly therefrom that is inserted into a corresponding tab-opening defined in one of the first and second rib assemblies. A lock member is slidably positioned in the slot, and an actuator is located in the space between the first and second rib assemblies. The actuator is operably coupled to the lock member for moving the lock member between first and second operative positions. A method of constructing a coupler is disclosed.