Patent Publication Number: US-6659708-B2

Title: Implement coupling assembly

Description:
This invention relates to an improved coupler assembly and more particularly to an assembly for detachably coupling an implement such as a bucket, grapple, rake and the like to the dipper stick of a machine such as an excavating machine. 
     BACKGROUND OF THE INVENTION 
     In the construction, mining and other industries involved in bulk material handling, it has been a common practice to provide an assembly mountable on the dipper stick of a machine such as an excavating machine for quickly coupling and uncoupling different implements such as buckets, grapples, rakes and the like to permit a variety of work functions to be performed without incurring extensive downtime of the machine which results in lower productivity. Although there are many of such coupling assemblies in the prior art which are operable to readily couple and uncouple such implements, it has been found that such assemblies are not greatly desirable for a number of reasons. Often, they are complicated in design, difficult and expensive to manufacture and install and/or require extensive modification of the dipper stick of the machine and/or the implements to be coupled to the dipper stick. They further often add weight to the end of the dipper stick which correspondingly reduces the lift capacity of the machine and/or increase the displacement of the implement from the dipper stick which correspondingly reduces the penetrating force of the coupled implement. It thus has been desirable to provide a simple coupler assembly which may be readily mountable on a conventional dipper stick of a machine and detachably connected to a number of conventional implements without extensive modification of such dipper stick and implements. 
     SUMMARY OF THE INVENTION 
     Many conventional excavating machines generally are provided with a wheel or track mounted chassis, a support platform mounted on such chassis and usually swingable about a vertical axis, a boom pivotally connected to such platform for pivotal movement about a horizontal axis, a first fluid actuated cylinder assembly operatively interconnecting the machine platform and the boom, a handle or dipper stick pivotally connected to the end of such boom, a fluid actuated cylinder assembly operatively interconnecting the boom and the dipper stick, and an implement pivotally mounted on the end of the dipper stick. Typically, the implement is operable to pivot about a horizontal axis and is actuated by a fluid actuated cylinder assembly operatively interconnecting the dipper stick and the implement. Such actuating assembly conventionally has consisted of a cylinder member having a base end connected to an upper side of the dipper stick, a rod member pivotally connected to a pair of support links pivotally connected to sides of the dipper stick adjacent its free end and a pair of actuating links interconnecting the support links with the implement. Normally, the implement is provided with a pair of mounting brackets on an upper wall thereof, in which there is provided a pair of spaced pins for connecting the implement to the end of the dipper stick and the free ends of the actuating links. With the implement thus attached, it will be appreciated that by operating the various fluid actuated cylinder assemblies, the front end of the machine may be swung, the boom and dipper stick may be raised and lowered and the implement, often an excavating bucket, may be curled and uncurled relative to the dipper stick, in performing various work functions. 
     In such an arrangement, the present invention contemplates providing brackets on such implements having pairs of opposed pin receiving recesses or modifying the mounting pin brackets of conventional implements by removing the connecting pins therefrom and cutting away the upper portions of the brackets to provide an upperwardly opening recess having a pair of opposed recessed portions consisting of portions of the connecting pin seats, utilizing the end of the dipper stick to provide a first connecting pin insertable into one set of the opposed recessed portions of the implement mounting brackets, and providing a second connecting pin rotatably mounted in the actuating links and insertable in the other set of opposed recessed portions of the implement brackets, and a pair of spacer links rigidly connected at one set of ends thereof to the second connecting pin for pivotal movement therewith and attachably connectable at the other set of ends thereof to the first connecting pin. 
     With the spacer links attached to the first connecting pin and the connecting pins inserted in the implement bracket recesses, such spacer links cooperate with a portion of the dipper stick and the support and actuating links to form a four bar linkage, and by simply operating the cylinder assembly interconnecting the dipper stick and the support links, the implement may be curled and uncurled, in the conventional manner. With the spacer links detached from the first connecting pin, allowing a collapse of the linkage, the boom and dipper stick may be maneuvered and the cylinder assembly interconnecting the dipper stick and the support links may be operated to displace the connecting pins relative to each other and thus permit the connecting pins to be inserted into and withdrawn from the implement bracket recesses to correspondingly couple and uncouple implements to the dipper stick. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of an assembly embodying the present invention, coupling an excavating bucket to the dipper stick of an excavating machine; 
     FIG. 1A is a side elevational view of the connection of the base end of the cylinder member of a fluid actuated assembly to the underside of the dipper stick shown in FIG. 1, having portions thereof broken away; 
     FIG. 2 is a perspective view of the embodiment of the invention shown in FIG. 1, illustrating the assembly in the uncoupled condition; 
     FIG. 3 is an enlarged cross sectional view taken along line  3 — 3  in FIG. 1; 
     FIG. 4 is a perspective view of an alternate spacer link which may be utilized in the coupling assembly shown in FIGS. 1 through 3; 
     FIG. 5 is a perspective view of an implement provided with an alternate set of attachment brackets which may be utilized in the implement of the embodiment shown in FIGS. 1 and 2, having a portion thereof broken away; 
     FIG. 6 is a perspective view of a conventional implement having a set of attachment brackets which may be modified to provide the type of implement attachment brackets shown in FIGS. 1 and 2, having a portion thereof broken away; 
     FIG. 7 is a perspective view of another embodiment of the present invention illustrating the implement uncoupled from the dipper stick of a machine; 
     FIG. 8 is a view similar to the view shown in FIG. 7, illustrating the implement coupled to the dipper stick; 
     FIG. 9 is an enlarged, perspective view of the coupling assembly of the embodiment shown in FIGS. 7 and 8, shown from a right side; 
     FIG. 10 is a view similar to the view shown in FIG. 9, shown from the left side; 
     FIGS. 11,  12  and  13  are enlarged side elevational views of one of the spacer links shown in FIGS. 9 and 10, illustrating a latch member thereof in a position being cammed into a latched position, the latch member in a latched position and the latch member in an unlatched position, respectively, and having a portion thereof broken away; 
     FIGS. 14 and 15 are views similar to the views shown in FIGS. 9 and 10, illustrating modifications thereof; 
     FIG. 16 is a perspective view of another embodiment of the invention, illustrating the assembly in the uncoupled condition; 
     FIG. 17 is a view similar to the view shown in FIG. 16, illustrating the assembly in the coupled condition; and 
     FIG. 18 is an enlarged perspective view of the coupling assembly shown in FIGS. 16 and 17, shown from the left side. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
     Referring to FIGS. 1 through 3 of the drawings, there is illustrated a dipper stick  10  of a excavating machine, an excavating bucket  11  and an assembly  12  for coupling the bucket on the free end of the dipper stick in the conventional manner. Dipper stick  10  is of a conventional construction and is pivotally connected at an upper end thereof to a boom, and is pivotal relative to such boom by means of a fluid actuated cylinder assembly. Rotatably mounted in the free end of dipper stick  10  is a first connecting pin  13  having a transversely disposed axis. Spaced from pin  13  is a mounting pin  14  having a transverse axis on which a pair of support links  15  and  16  are mounted for pivotal movement in parallel planes, relative to the dipper stick. The free ends of the support links are pivotally connected to a connecting pin  17  on which there also are pivotally connected the upper ends of a pair of actuating links  18  and  19 . Operatively interconnecting the upper side of dipper stick  10  and connecting pin  17  is a fluid actuated cylinder assembly  20  including a cylinder member  20   a  having the base end thereof pivotally connected to a set of brackets  20   b  mounted on the underside of the dipper stick, and a rod member  20   c  pivotally connected at its free end to connecting pin  17 . 
     Rotatably mounted in the lower ends of actuating links  18  and  19  is a connecting pin  21  having a transverse axis disposed parallel to the axes of connecting pins  13  and  17 . A set of spacer links  22  and  23  are rigidly secured to the ends of connecting pin  21  and extend substantially radially relative thereto. The free ends of the spacer links are provided with forwardly and downwardly facing recesses  24  and  25  which are adapted to receive the outer ends of connecting pin  13  when such links are rotated in a counterclockwise direction about the axis of connecting pin  21 . When the surfaces of recesses of  24  and  25  are seated on the outer ends of connecting pins  13 , such links may be secured in such positions by a pair of latch mechanisms  26 . Each of such latch mechanisms includes a small set of brackets  27  mounted on an end surface of connecting pin  13 , a latch element  28  having an end thereof received within brackets  27  and pivotally connected thereto by means of a pin, and a set of brackets  29  in which the free end of the latch element may be received and secured by means of a pin when the surfaces of recesses  24  and  25  are seated on the ends of connecting pin  13 . 
     With the surfaces of recesses  24  and  25  seated on the outer ends of connecting pin  13  and the free ends of the spacer links latched to the ends of connecting pin  13 , the base links cooperate with a portion of the dipper stick disposed between connecting pin  13  and mounting pin  14 , support links  15  and  16  and actuating links  18  and  19  to form a pair of laterally spaced four bar linkages. With such linkages thus intact, the cylinder assembly operatively interconnecting the underside of the dipper stick and connecting pin  17  may be operated to pivot spacer links  22  and  23  about the axis of connecting pin  13 . When the spacer links are unlatched, operation of the cylinder assembly between the dipper stick and connecting pin  17  will cause support links  15  and  16  to pivot about the axis of mounting pin  14  and thus allow connecting pins  13  and  21  to displace relative to each other. 
     Bucket  11  is of a conventional configuration except for the mounting brackets. It is provided with a pair of laterally spaced side walls  30  and  31  and an adjoining wall including an upper wall section  32 , a downwardly and forwardly curved, rear wall section  33  and a forwardly extending bottom wall section  34  terminating at a front cutting edge  35 . Rigidly mounted on the front cutting edge is a set of laterally spaced teeth  36 . Rigidly secured to the upper wall section  32  is a pair of identical, laterally spaced mounting brackets  37  and  38 . As best seen in FIG. 2, mounting bracket  37  is recessed in an upper edge thereof as at  39  providing an entry or access way and a pair of lower guide surfaces  40  and  41  inclined toward a pair of opposed pin receiving recess portions  42  and  43 . Such forwardly disposed recess portions are transversely aligned and are adapted to receive the end portions of connecting pin  13 , and such rearwardly disposed recess portions also are transversely aligned and are adapted to receive end portions  21   a  and  21   b  of connecting pin  21 , when the bucket is connected to the dipper stick as shown in FIG.  1 . 
     With bucket  11  positioned on the ground and spacer members  22  and  23  unlatched from pin  13  as shown in FIG. 2, such bucket may be coupled to the dipper stick first by manipulating the dipper stick to insert the ends of connecting pin  13  in the forwardly disposed recess portions of the mounting brackets, and then operating the cylinder assembly  12  to insert and thus position end portions  21   a  and  21   b  of connecting pin  21  in the rearwardly disposed recess portions of the mounting brackets. When connecting pins  13  and  21  are thus positioned in mounting brackets  37  and  38 , and the forward ends of links  22  and  23  are positioned with the wall portions of recesses  24  and  25  seated on the ends of connecting pin  13 , the base members may be latched to connecting pin  13  to pivotally couple the bucket to the dipper stick. 
     In maneuvering the dipper stick to position the ends of connecting pin  13  in the forwardly disposed recess portions of the mounting brackets, the bottom wall edges of the bracket recesses, inclined toward the forwardly disposed recess portions, function to guide the ends of connecting pin  13  into the forwardly disposed recess portions of the bracket recesses. Similarly, the surfaces engaged by connecting pin end sections  21   a  and  21   b , function to guide such pin sections into the rearwardly disposed recess portions of the mounting brackets. With the bucket thus coupled, the cylinder assembly interconnecting the underside of the dipper stick and assembly  12  may be operated to curl and uncurl the bucket in the conventional manner. 
     During pivotal movement of the dipper stick and/or the curling and uncurling of the bucket by means of the operation of the cylinder assembly interconnecting the dipper stick and assembly  12 , the principal function of spacer links  22  and  23  is to maintain connecting pins  13  and  21  in the opposed recessed portions of the bucket mounting brackets. No substantial applied or reactive forces are transmitted through the spacer links. Instead, such forces are transmitted from the dipper stick to the bucket through connecting pins  13  and  21 . 
     It will be appreciated that conventional excavating machines provided with a dipper stick, a bucket pivotally connected to the end of the dipper stick and a cylinder assembly operatively interconnecting the upper side of the dipper stick and the bucket through a set of actuating links supported on a pair of support links, may easily and comparatively inexpensively be modified to provide the coupling arrangement of the present invention, simply by providing a pair of mounting brackets similar to brackets  37  and  38  on the bucket, utilizing the lower ends of actuating links  18  and  19  to provide a rotatably mounted connecting pin  21 , providing a pair of spacer links  22  and  23  rigidly connected to the ends of the connecting pin  21  rotatably mounted in the lower ends of the actuating links, utilizing the end portion of the dipper stick to provide a connecting pin  13  and providing a set of latching mechanisms  26  for securing the forwardly disposed ends of the spacer links to the ends of connecting pin  13 . 
     FIG. 6 illustrates a conventional excavating bucket which may be modified to provide a bucket compatible with the present invention as shown in FIG.  2 . Such conventional bucket typically includes a pair of laterally spaced mounting brackets  50  and  51  rigidly secured to the upper wall section of the bucket, and a pair of transversely disposed, longitudinally spaced connecting pins  52  and  53  mounted in suitable bracket openings. Such bucket may be modified to be compatible with the arrangement of the present invention simply by removing connecting pins  52  and  53  and then cutting recesses in the midportions of the upper edges of the brackets thereof communicating with the openings of connecting pins  52  and  53  to provide opposed recess portions and lower guide surfaces extending toward such opposed recess portions as shown in FIG.  2 . Alternatively, and particularly for new bucket constructions, brackets of a configuration as shown in FIG. 5 may be provided which simply may be rigidly secured, usually by welding, to the upper wall section of a bucket. Similarly to mounting brackets  37  and  38 , each of brackets  60  and  61  shown in FIG. 5 consists of a piece of metal of suitable length, depth and thickness, recessed at a midpoint in an upper edge thereof as at  62  to provide a pair of opposed recessed portions  63  and  64  and a pair of guide surfaces  65  and  66  which are inclined from a midpoint toward recessed portion  63  and  64 , respectively. 
     Connecting pins  13  and  21  are formed of hardened steel and are provided with sufficient tensile strength to carry the various loads imposed during typical digging operations. Spacer members  22  and  23  may be formed of carbon steel castings or may be formed from steel plate. To prevent undue wear of surfaces  24  and  25 , hardened steel inserts  24   a  and  25   a  may be provided as shown in FIG.  2 . In addition, in lieu of providing the forwardly disposed ends of spacer links  22  and  23  with forwardly and downwardly opening recesses  24  and  25 , such links may be provided simply with downwardly opening recesses as shown in FIG.  4 . Such figure illustrates spacer links  70  and  71  rigidly mounted at rear ends thereof to a connecting pin  21 , having downwardly opening recesses  72  and  73  adapted to receive end portions of a connecting pin  13 . As in the previously described embodiment, latch mechanisms would be provided to secure the front ends of base links  70  and  71  to connecting pin  13 . 
     Referring to FIGS. 7 through 13, there is illustrated a dipper stick  80  of an excavating machine, an excavating bucket  81  and an assembly  82  for coupling the bucket to the free end of the dipper stick, incorporating another embodiment of the invention. Dipper stick  80  is similar in construction and operation to dipper stick  10  described in connection with the embodiment shown in FIGS. 1 through 6. Coupling assembly  82  includes a connecting pin  83 , a mounting pin  84 , a pair of connecting pins  85  and  86 , a pair of support links  87  and  88 , a pair of actuating links  89  and  90  and a pair of spacer links  91  and  92 . Connecting pin  83  is mounted adjacent the free end of the dipper stick and is disposed transversely relative to the centerline of the dipper stick. Mounting pin  84  is spaced from and disposed parallel to connecting pin  83 . Support links  87  and  88  are pivotally connected at one set of ends thereof to mounting pin  84 , straddling the dipper stick, and are pivotally connected at an opposite set of ends thereof to connecting pin  85 . Also connected to connecting pin  85  at one set of ends thereof are actuating links  89  and  90 , inboard of support links  87  and  88 . The opposite set of ends of the actuating links is pivotally connected to connecting pin  86 . Spacer links on  91  and  92  are rigidly connected to the outer ends of connecting pin  86  and are adapted to engage the outer ends of connecting pin  83  in abutting relation and thus cooperate with a portion of the dipper stick, the support links and the actuating links to form a pair of four bar linkages. When the spacer links engage the outer ends of connecting pin  83  to form such linkages, assembly  82  may be pivoted relative to the dipper stick about the axis of connecting pin  83  by means of a hydraulic cylinder assembly operatively interconnecting the upper side of the dipper stick and assembly  82  by means of a rod member  93  pivotally connected to connecting pin  85  between support links  87  and  88 . 
     Bucket  81  is provided on an upper wall portion thereof with a pair of mounting brackets  94  and  95  which are comparable to mounting brackets  37  and  38  described in connection with the embodiment shown in FIGS. 1 through 6, and are adapted to be engaged by assembly  82  to detachably couple bucket  81  to dipper stick  80 . As in the previously described embodiment, the mounting brackets are provided with access openings  96  and  97  in the upper edges thereof, communicating with a first set of recesses  98  and  99  adapted to receive end portions of connecting pin  83 , and a set of opposed recesses  100  and  101  adapted to receive the outer end portions of connecting pin  86  when assembly  82  is coupled to bucket  81 . 
     As best shown in FIGS. 9 and 10, connecting pin  83  is provided with a pair of flanges  102  and  103  mounted on the ends thereof, and is formed with a set of flat surfaces adjacent such flanges which are adapted to be engaged by the free ends of the spacer links when assembly  12  is in the coupled or operative condition as shown FIG. 8, forming a four bar linkage. One end of connecting pin  83  is provided with a square head portion  104  which is adapted to be engaged by an open ended wrench  105 , as shown in FIG. 7, to rotate the connecting pin and thus position the flat portions of the pin in alignment with the engaging front end portions of the spacer links. 
     The free ends of spacer links  91  and  92  are provided with hardened contact plates  106  and  107  which are adapted to engage the flat, aligned surfaces of connecting pin  83 . Such plates may be secured to the front ends of the spacer links by means of a set of screws and further may be provided with shims to provide any necessary adjustment in the length of the spacer links to assure a firm engagement with the flat contact portions of connecting pin  83 . 
     As best shown in FIG. 9, the inner side of spacer link  91  is provided with a latch element  108  which is secured to a pin  109  journaled in a transverse opening in link  91 . The latch element has essentially a hook shaped configuration including a pair of converging side edges  110  and  111  terminating in a hook portion  112  curving from side edge  110  into an arcuate recessed portion  113  merging with opposite side edge  111 . The latch element normally is biased in a clockwise direction relevant to FIG. 9, against a stop element  114  mounted on the inner side of link  91  by means of a spring  115  anchored on a small bracket  116  secured to the inner side of link  91 . 
     The function of latch  108  is to maintain the front ends of spacer links  91  and  92  into engagement with the flat abutment surfaces of connecting pin  83  when assembly  12  is coupled to bucket  81  with connecting pin  83  received in recesses  98  and  99  of mounting brackets  94  and  95  and connecting pin  86  received in recesses  100  and  101  of the mounting brackets. This is accomplished by the latching element latching onto an eccentric roller  117  bolted on the outer side of mounting bracket  94  as shown in FIG.  7 . 
     Latch element  108  is adapted to be cammed into a latching position with roller  107  when the coupling assembly is attached to the bucket and the spacer links are caused to pivot about the axis of connecting pin  86 , as shown in FIG. 11, be locked in a latched position when assembly  12  is coupled to the bucket as shown in FIG.  12  and be released from the latched position to permit the uncoupling of the bucket as shown in FIG.  13 . During the coupling of assembly  12  to the bucket and correspondingly the pivotal movement of the spacer links about the axis of pin  86 , the curved end portion of the latch element will engage roller  84  and thus be cammed to rotate in a clockwise position against the biasing action of spring  15  to cause roller  117  to be received within recess  113  of the latch element when the spacer links pivot to their farthest travel into engagement with connecting pin  83 , as shown in FIG.  12 . With the latch element engaging roller  117  as shown in FIG. 12, an opening  118  in the latch element will register with an opening  119  in spacer link  91  to receive a locking pin  120  provided with a retention pin  121 . When it is desired to free the spacer links to uncouple the bucket from the dipper stick, the latch element may be unlatched from roller  117  merely by removing the locking pin and rotating the latch element as shown in FIG.  13 . Such rotation of the latch element may be accomplished with the use of wrench  105  applied to a square head portion  122  formed on the outer side of pin  109  as shown in FIG.  10 . 
     When assembly  82  is in the inoperative condition as shown in FIG. 7, the spacer links may be retained in retracted, inoperative positions adjacent the outer sides of actuating links  89  and  90  by means of inserting the elongated shank portion of wrench  105  through a set of openings  123  and  124  adapted to register with a set of openings  125  provided in a set of brackets  126  mounted on the rear sides of actuating links  89  and  90 . 
     With assembly  82  in the inoperative condition as shown in FIG. 7, the bucket may be connected to the dipper stick as shown in FIG. 8 initially by manipulating the dipper stick to insert the ends of connecting pin  83  into the forwardly disposed recess portions of the mounting brackets, and then operating the cylinder assembly to insert and thus position the end portions of connecting pins  86  in the rearwardly disposed recess portions of the mounting brackets. When connecting pins  83  and  86  have thus been positioned in the mounting brackets of the bucket, the spacer links may be released from their stored or retracted positions connected to the actuating links and permitted to pivot downwardly about the axis of connecting pin  86  so that the front ends thereof engage the flat portions of connecting pin  83 . If the flat portions of connecting pin  83  are not properly aligned to be engaged by the front ends of the spacer links, pin  83  may be rotated by the use of wrench  105 . As the spacer links thus pivot downwardly into position for maintaining connecting pins  83  and  86  in the recesses of the mounting brackets, the leading, rounded end portion of the latch element will engage roller  117 , causing the latch element to pivot upwardly against the biasing action of spring  115 , to permit the end of the latching element to ride over the roller and cause the roller to be received within recess  113  of the latch element as shown in FIG.  12 . With the latch element in the latched position, locking pin  120  may be inserted through registered openings  119  and  120  and retaining pin  121  may be inserted through the locking pin to lock the spacer links in their operative position forming a four bar linkage. Under such conditions, the bucket will be pivotally connected to the dipper stick and the machine may be operated in the conventional manner to perform various excavating operations. 
     When it is desired to uncouple the bucket from the dipper stick, retaining pin  121  and locking pin  120  may be removed, wrench  105  may be applied to the head portion of pin  109  to pivot the latch element out of engagement with roller  117  as shown in FIG. 13 to free the spacer links and then the spacer links may be pivoted rearwardly alongside the actuating links where they may be retained by inserting the elongated shank portion of the wrench through registered openings in the spacer links and brackets on the rear end of actuating links. 
     FIG. 14 illustrates a modification of the spacer links described in connection with the embodiment shown in FIGS. 7 through 13. The modification includes a set of spacer links  91   a  and  92   a  similar in construction and function to spacer links  91  and  92  with the exception of the configuration of the front end portions thereof. Such free end portions are formed with a configuration similar to the front end portions of spacer links  22  and  23  described in connection with the embodiment shown in FIGS. 1 through 6, providing forwardly and downwardly opening recesses adapted to receive the end portions of connecting pin  83 . It further is contemplated that the front end portions of spacer links  91   a  and  92   a  may be formed with downwardly opening recesses formed adjacent the free ends thereof similar to the spacer links shown in FIG. 4, for receiving the end portions of connecting pin  83 . FIG. 15 is another modification of the spacer link assemblies shown in FIGS. 9 and 10 in which a pair of bushings  127  and  128  may be mounted on the end portions of connecting pin  83  and a similar set of bushings  129 ,  129  may be mounted on the ends of connecting pin  86  to center coupling assembly  82  relative to the dipper stick. 
     FIGS. 16 through 18 illustrate another embodiment of the invention which is similar to the embodiments shown in FIGS. 1 through 6 and  7  through  15  with the exception of the means for securing the free ends of the spacer links to the connecting pin mounted on the lower end of the dipper stick. Referring to such figures, there is illustrated a dipper stick  130  of an excavating machine, an excavating bucket  131  and an assembly  132  for coupling the bucket to the free end of the dipper stick. Dipper stick  130  is similar in construction and operation to dipper stick  10  described in connection with the embodiment shown in FIGS. 1 through 6. Bucket  131  is similar to bucket  11  described in connection with the embodiment shown in FIGS. 1 through 6 and is adapted to be engaged by assembly  132  to detachably couple the bucket to the dipper stick. As in the previously described embodiments, the mounting brackets of the bucket are provided with access openings  133  and  134  in the upper edges thereof, communicating with a first set of recesses  135  and  136  and a set of opposed recesses  137  and  138 . As best shown in FIG. 16, the sides of the mounting brackets of the bucket are provided with bosses about the recesses therein to impart greater strength to the portions of the brackets adjacent the recesses therein. 
     Coupling assembly  132  includes a connecting pin  139 , a mounting pin  140 , a pair of connecting pins  141  and  142 , a pair of support links  143  and  144 , a pair of actuating links  145  and  146  and a pair of spacer links  147  and  148 . Connecting pin  139  is mounted adjacent the free end of the dipper stick and is disposed transversely relative to the center line of the dipper stick. Mounting pin  140  is spaced from and disposed parallel to connecting pin  139 . Support links  143  and  144  are pivotally connected at one set of ends thereof to mounting pin  140 , straddling the dipper stick, and are pivotally connected at an opposite set of ends thereof to connecting pin  141 . Also connected to connecting pin  141  at one set of ends thereof are actuating links  145  and  146 , inboard of support links  143  and  144 . The opposite set of ends of the actuating links is pivotally connected to connecting pin  142 . Spacer links  147  and  148  are rigidly connected to outer ends of connecting pin  142  and are adapted to engage the outer ends of connecting pin  139  in abutting relation and thus cooperate with a portion of the dipper stick, the support links and the actuating links to form a pair of four bar linkages as in the previously described embodiments. When the spacer links engage the outer ends of connecting pin  139  to form such linkages, assembly  132  may be pivoted relative to the dipper stick about the axis of connecting pin  139  by means of a hydraulic cylinder assembly operatively interconnecting the upper side of the dipper stick and assembly  132  and provided with a rod member  149  pivotally connected to connecting pin  141  between support links  145  and  146 . 
     Referring to FIG. 18, the lower portions of the free ends of spacer links  147  and  148  are recessed as at  150  which are adapted to receive an end portion of connecting pin  139 , and provide a pair of projecting portions  151  and  152  adapted to rest on the ends of connecting pin  139  when such end portions are received within such recesses. Cooperating with the free ends of the spacer links is a pair of latch members  153  and  154 , sometimes referred to “crow claws,” each pivotally connected to an outer side of a spacer link. Latch member  153  is pivotally connected to spacer link  147  by means of a pin  155 , and further is provided with an opening on one side of the pivotal connection of the member with the spacer link, which is adapted to register with an opening in spacer link  147  to receive a locking pin  156  therethrough for locking latch member  153  to spacer link  147  in the position as shown in FIG.  18 . The portion of such member on the opposite side of pin  155  is provided with a recess  157  having a radius of curvature substantially similar to the radius of an end portion of connecting pin  139  so that when projecting portion  151  rests on an end of connecting pin  139  and latch member  153  is in its locked position, as shown in FIG. 18, the end portion of connecting pin  139  will be received within recess  157  to preclude the displacement of spacer link  147  relative to connecting pin  139  about the axis of connecting pin  142 . 
     Latch member  153  is formed with a greater portion of its mass disposed on the side of the member including recess  157 , relative to the axis of pin  155 , so that when member  153  is unlocked from spacer link  147  and free to pivot about the axis of pin  155 , it will be caused to pivot downwardly, engage a stop  158  and assume a position as shown in FIG.  16 . Latch member  154  is similar in construction and mounting relative to latch member  153  and is adapted to pivot about the axis of a pivot pin disposed coaxially with pivot  155 . Latch members  153  and  154  are adapted to pivot about an axis disposed parallel to the axis of connecting pin  139  and receive the end portions of connecting pin  139  in the recesses thereof, as the spacer links pivot about the axis of connecting pin  142  and projecting portions  151  and  152  thereof are caused to engage and rest on the outer ends of connecting pin  139 . 
     The spacer links further are provided with a pair of handles  159  and  160  which may be gripped by an operator to pivot the links about the axis of connecting pin  142  to a storage position as shown in FIG.  16 . They further are provided with a pair of transversely aligned openings  161  and  162  which are adapted to register with openings provided in actuating links  145  and  146  and openings in latch members  153  and  154  through which locking pins  156  and  156   a  may be received to lock the latch members in the position as shown in FIG. 18, when the spacer links are disposed in the positions shown in FIG. 16, so that locking pins  156  and  156   a  may be inserted through such registered openings to secure the spacer links in their stored positions as shown in FIG.  16 . 
     With bucket  131  positioned on the ground, the dipper stick positioned adjacent the upper end of the bucket and the spacer links in the stored positions as shown in FIG. 16, the bucket may be detachably connected to the dipper stick as shown in FIG. 17 by operating the cylinder assembly interconnecting coupling assembly  132  and the upper side of the dipper stick to cause connecting pins  139  and  142  to be drawn together a sufficient amount to permit them to be received within access openings  133  and  134  of the mounting brackets of the bucket, maneuvering the dipper stick to cause the end portions of connecting pin  139  to be received within recesses  135  and  136 , operating the cylinder assembly connected to coupling assembly  132  to extend rod member  149  and thus cause connecting pin  142  to be received within recesses  137  and  138  of the mounting brackets, removing locking pins  156  and  156   a  to allow spacer links  147  and  148  to be freed from the actuating links and swing downwardly to engage the ends of the connecting pin  139  and then inserting locking pins  156  and  156   a  into registered openings in the latch members and spacer links to preclude the displacement of the spacer links relative to connecting pin  139 . 
     As the spacer links are freed from the actuating links by removing locking pins  156  and  156   a , they will be caused to pivot downwardly about the axis of connecting pin  142 , the upper surfaces of recesses of the latch members will first engage the outer ends of connecting pin  139  causing them to pivot upwardly about the common axis of their pivot pins, and then the lower surfaces of projecting portions  151  and  152  will engage the upper surfaces of the end portions of connecting pin  139  so that the spacer links will be positioned as shown in FIGS. 17 and 18. Locking pins  156  and  156   a  may then be inserted in registered openings in the latch members and spacer links to secure the spacer links to connecting pin  139 . With the spacer links thus secured to connecting pins  139  and  142 , they will be prevented from being removed from the recesses in the mounting brackets of the bucket. The cylinder assembly operatively interconnecting the dipper stick and the coupling assembly may then be operated in the conventional manner to curl and uncurl the bucket relative to the dipper stick. 
     The function of the spacer links in each of the described embodiments is to retain the pins connected to the implement, in the recesses of the mounting brackets of the implement and allow them to pivot relative to the implement. Such links may be rigidly secured to either of such connecting pins or could be unsecured thereto, and can be detachably secured by latching or otherwise to either of such connecting pins or the implement to prevent their displacement during use. 
     It will be appreciated that the present invention provides an arrangement whereby a conventional excavating machine and a plurality of conventional implements including buckets, grapple, rakes and the like may be easily and inexpensively modified to permit such machines to easily couple and uncouple a variety of implements. Such arrangement involves not only simple modifications of the machine dipper stick and the implements to be coupled to the machine but the addition of only a few components. 
     From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those persons having ordinary skill in the art to which the aforementioned invention pertains. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.