Abstract:
A coupler device for adapting a variety of excavator apparatuses to engage a variety of excavating buckets. The coupler device has a mounting plate, a connecting device for connecting the mounting plate to the excavator apparatus, and a device for connecting the mounting plate to the excavating bucket. The device connecting the mounting plate to the excavator apparatus may include a plurality of holes adapted to fit a variety of excavator apparatuses. The device for connecting the mounting plate to the excavating bucket may include a front hook, a rear hook, and a device moving the rear hook with respect to the front hook to adapt to a variety of excavating buckets. The device for moving the rear hook may include a captured bolt threaded through a cast box support that is attached to the slidable plate.

Description:
This application is a continuation-in-part of U.S. provisional application Ser. No. 60/071,236 filed Jan. 12, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to the field of earth moving machinery and more particularly to an adjustable coupler system for coupling a variety of earth moving buckets of different sizes and different manufacturers to a variety of sizes of hydraulic excavators. 
     BACKGROUND OF THE INVENTION 
     Manufacturers of hydraulic excavator machines are notorious for constructing the connection end of the machine, called the stick or boom, such that only buckets specifically designed for that model of machine can be attached. As a result, distributors and users of the machines are forced to carry a large inventory of buckets in order to have buckets of varying sizes (widths and capacities) for each machine owned or leased. Such inventory is expensive and space consuming. Accordingly, it is desirable to provide a mechanism that would allow different sizes and styles of buckets to be coupled to any one of a variety of hydraulic excavators. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a coupler device for releasably interconnecting an excavating bucket having a pair of pins to an excavator apparatus. The coupler device includes a mounting plate, a means for connecting the mounting plate to the excavator pigging mechanism, and a means for connecting the mounting plate to the excavating bucket. 
     The means for connecting the mounting plate to the excavator apparatus in one embodiment includes a first pin and a second pin, and a first flange member and a second flange member spaced apart from the first flange member, wherein the first flange member and the second flange member are both attached to an upper surface of the mounting plate. In one embodiment of the present invention, the first flange member and the second flange member each contain two holes such that the first pin aligns with and passes through a first hole in the first flange member, then through corresponding holes in the excavator apparatus, then through a matching hole in the second flange member, while the second pin aligns with and passes through a second hole in the first flange member, then through corresponding holes in the excavator apparatus, then through a matching hole in the second flange member. In another embodiment of the present invention, the first flange member includes a third hole and the second flange member includes a third matching hole, wherein the third hole and the third matching hole are operable to receive the second pin. Adding a third hole to the flange members allows the coupler device to have a different spacing between the front and rear connection points for changing the effective leverage. 
     In another embodiment of the present invention the means for connecting the mounting plate to the excavator apparatus includes a first pin and a second pin, a first flange member and a second flange member spaced apart from the first flange member, wherein the first flange member and the second flange member are both attached to an upper surface of the mounting plate, and wherein the first flange member and the second flange member each include one hole such that the first pin aligns with and passes through the hole in the first flange member then through corresponding holes in the excavator apparatus, then through the hole in the second flange member, a slidable plate that is slidably attached to the mounting plate, and a third flange member and a fourth flange member spaced apart from the third flange member, wherein the third flange member and the fourth flange member are both attached to an upper surface of the slidable plate, and wherein the third flange member and the fourth flange member each include one hole such that the second pin aligns with and passes through the hole in the third flange member, then through corresponding holes in the excavator apparatus, then through the hole in the fourth flange member. 
     In one embodiment of the present invention, the means for connecting the mounting plate to the excavating bucket includes a forward-facing front hook that is attached to a lower surface of the mounting plate and is operable to engage a first of the pins on the excavating bucket, a slidable plate that is slidably attached to the mounting plate, a first side plate and a second side plate spaced apart from the first side plate, wherein the first side plate and the second side plate are both attached to a lower surface of the slidable plate and are formed with downward-facing U-shaped opening which are operable to engage a second pin on the excavating bucket, a forward-facing rear hook movably attached to the lower surface of the slidable plate, and a means for moving the rear hook with respect to the slidable plate so that the rear hook is operable to secure the second pin within the U-shaped openings. 
     In one embodiment of the present invention, the means for moving the rear hook includes a bolt support that is attached to the slidable plate and a bolt that is threaded through the bolt support and attached to the rear hook so that rotation of the bolt moves the rear hook axially of the slidable plate. The slidable plate may be moved axially along the mounting plate and, in one embodiment of the present invention, secured thereto using bolts. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a side elevation view of a coupler constructed in accordance with the teachings of the present invention; 
     FIG. 1A is a side elevation view of an alternate embodiment of a coupler in accordance with the present invention; 
     FIG. 1B is a side elevation view of an alternate embodiment of a coupler in accordance with the present invention; 
     FIG. 1C is a rear elevation view of the coupler of FIG. 1B, 
     FIG. 2 is a top plan view of the coupler of FIG. 1B; 
     FIG. 3 is a front end view of the coupler of FIG. 1; 
     FIG. 4 is a rear end view of the coupler of FIG. 1; 
     FIG. 5 is a simplified side view of an excavating bucket, excavator apparatus, and the coupler of FIG. 1 showing hook-up pin positions; 
     FIG. 6 is a side view of a portion of one of the hooks of the coupler of FIG. 1 showing the hook opening; 
     FIG. 7 is a side view of the clevis plate of the coupler of FIG. 1 showing the opening design; 
     FIGS. 8 and 8A are elevation and plan views of an alternate embodiment of the coupler of FIG. 1; and 
     FIG. 9 illustrates application of hydraulic actuators to the embodiment of FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings in general and in particular to FIGS. 1 and 4, the present invention is implemented in a coupler  10  having a pair of spaced flange members  12   a ,  12   b  attached to an upper surface of a mounting plate  14 . A pair of spaced holes  16   a ,  16   b  are formed in each flange member with the holes  16   a  and the holes  16   b  aligned in both flange members  12   a ,  12   b  for passing a pair of pins  18   a ,  18   b  shown in phantom. The pins  18   a ,  18   b  are used to connect the coupler  10  to an end of a stick on an earth moving machine, such as, for example, a Caterpillar 330B or a Daewoo DH280 excavator. Each of these excavators will have a different pin position, and the flanges  12   a ,  12   b  and holes  16   a ,  16   b  of the embodiment of FIG. 1 are uniquely adapted to fit and connect to one of these machines. 
     Referring specifically to FIG. 1A, in another embodiment of the present invention, the spaced flange members  12   a ,  12   b  each contain an extra rear hole  16   c  which can be used for increased leverage. The third hole  16   c  is formed in each spaced flange member  12   a ,  12   b  as a connection point for a hydraulic powered lever arm with more spacing from the front pivot connection  16   a  for higher leverage. 
     Referring specifically to FIGS. 1B,  1 C AND  3 , in yet another embodiment of the present invention, there are two pairs of spaced flange members  12   a ,  12   b ,  12   c ,  12   d . A first pair of spaced flange members  12   a ,  12   b  are attached to the upper surface of the mounting plate  14  above a front hook  22 . A second pair of spaced flange members  12   c ,  12   d  are attached to an upper surface of a slidable plate  38  which is slidably supported on a pair of L-shaped support brackets  40   a ,  40   b  that are attached to the mounting plate  14 . Preferably, the brackets  40   a ,  40   b  are welded to the mounting plate  14 . The slidable plate  38  can be moved to adjust the position of the second pair of spaced flange members  12   c ,  12   d  in relation to the first pair of spaced flange members  12   a ,  12   b  so that the coupler  10  may fit a larger number of earth moving machines. 
     Referring now to FIGS. 1 and 3, on a lower surface of the mounting plate  14  there is attached the front hook  22 . As seen in the front view of FIG. 3, the hook  22  extends laterally about the width between the upper flanges  12   a ,  12   b , thus providing a wide and robust hook. As will become apparent, the hook  22  is designed to fit about a pin on the top of a conventional excavator bucket. 
     As shown in FIG. 5, each bucket  24  is fitted with a pair of spaced pins  26   a ,  26   b  which are normally used to couple the bucket  24  directly to the end of the excavator stick  27 . Since the pin positions are dictated by the design of the stick end, buckets are generally unique to a particular stick. For that reason, any change in stick design and particularly in pin position, requires a different bucket. Pin diameters may also vary making buckets more unique. Further, buckets having different capacities, for example, ½ yard buckets as compared with 3 yard buckets, may have different widths. A bucket&#39;s pin width is usually set to match a particular excavator stick. 
     Referring to FIG. 1 and 4, side plates  34   a ,  34   b  are formed with inverted, generally U-shaped openings  36  sized to fit onto a rear pin  26   b  on an excavator bucket. The side plates  34   a ,  34   b  are positioned on either side of a rear hook  28  and cooperate with the rear hook  28  to create a positive locking mechanism for attaching a bucket  24  to the coupler  10 . The side plates  34   a ,  34   b  are attached to a lower surface of the slidable plate  38 . Preferably, the side plates  34   a ,  34   b  are welded to the slidable plate  38 . 
     Referring to FIGS. 1,  2 , and  4 , the positions of the side plates  34   a ,  34   b  and their downward facing opening  36  is adjustable with respect to fixed front hook  22  so that the coupler can be used on different models and sizes of excavator buckets. Adjustment is attained by sliding the slidable plate  38  to the desired location, passing each of a pair of bolts  44  first through a locking bar  41  and then through one of the two slots  42  in the mounting plate  14 , and threadedly engaging slidable plate  38 . With the bolts  44  loosened, the plate  38  will slide on brackets  40   a ,  40   b  allowing the spacing between front hook  22  and openings  36  to be set to fit the spacing between a pair of bucket pins. The bolts  44  are then tightened to fix the position of plate  38 . The locking bars  41  grip the mounting plate  14  and help ensure that the position of plate  38  remains fixed. 
     Referring now to FIG. 5, the rear pin  26   b  on a bucket  24  is also held by the rear hook  28 . After the coupler  10  is placed on a bucket  24  and the slidable plate  38  is adjusted and secured in a position so that the side plates  34   a ,  34   b  engage the rear pin  26   b , the rear hook  28  must be moved toward the front hook  22  in order to capture and hold the rear pin  26   b  in the clevis formed by opening  36 . 
     The rear hook  28  is movably attached to the lower surface of the slidable plate  38 . More precisely, the rear hook  28  includes an upper support plate  30  which rides on the shoulders  32  of the side plates  34   a ,  34   b . In the embodiment of FIG. 1, this adjustment is achieved by a captured bolt  46  threaded through a cast box support  48  which is welded to slidable plate  38 . The cast box support  48  contains a large nut that is captured within the box  48 . This nut can be replaced if its threads are damaged. A locking nut  50  is used to prevent inadvertent retraction of bolt  46 . A guide block  51  is attached to the end of the captured bolt  46  and the rear hook  28 . As the captured bolt  46  is threaded through the cast box support  48 , the guide block  51  applies a lateral force to the rear hook  28 , causing the upper support plate  30  to move on the shoulders  32  of the pair of spaced side plates  34   a ,  34   b . In this way, the position of the rear hook  28  in relation to the side plates  34   a ,  34   b  can be altered so that the rear hook  28  may securely engage the rear pin  26   b  of the bucket  24 . 
     Note that a hook-up bracket  52  may be welded to the mounting plate  14  for connecting a cable or chain which may be used to lift various items such as pipe being laid in an excavated trench. In addition, conventional Zerk type grease fittings  39  are provided to lubricate sliding interfaces throughout the coupler  10 , as illustrated in FIG.  2 . 
     It will be noted that each hook  28  and  22  and the side plates  34   a ,  34   b  are formed with openings that are not uniformly circular. The openings, such as opening  36 , are designed to provide maximum contact surface on the bucket pins and to have a constricting shape in which the pins do not immediately bottom out in the openings. Referring to FIG. 6, the opening  36  of plate  34   a  is defined within an arc of 56° with the forward inner surface lying on an arc of 8 inch radius. As shown by the two different pin diameters at lines  56  and  58 , the contact surfaces are maximized without bottoming of the pins so that different size pins can be engaged with one size opening. Similarly, as shown in FIG. 7, the opening of the hook  22  is designed for the same type contact but is formed with an opening of 28° of arc. The inner lower surface is formed with an 8 inch radius. It is anticipated that the bucket pins may be manufactured of a low hardness steel that will allow some outer surface deformation of the pins in order to increase the surface contact with the hooks  22 ,  28  and plates  34   a ,  34   b.    
     FIGS. 8 and 8 a  illustrate an alternate embodiment of a coupler  60  for an excavator bucket. The coupler  60  uses a pair of oppositely facing hooks  62  and  64  with the rear hook  64  being slidably adjustable. The upper portion of the coupler  60 , i.e., the mounting plate  14  and flange members  12   a ,  12   b , are substantially identical to the embodiment of the coupler  10  of FIG.  1 . In FIG. 8, the rear hook  64  is attached to a plate  66  which is supported by a pair of rails  68   a ,  68   b  welded to the underside of plate  14  in a manner similar to the support brackets  40   a ,  40   b  of FIG.  4 . The slots  42  in plate  14  are similarly used with the bolts  44  to lock the plate  66  in position once the rear hook  64  has engaged the rear pin on the bucket. Adjustment of rear hook position is achieved via a captured bolt  70  rotatably fixed to mounting plate  14  by a pair of guide brackets  72   a ,  72   b . The bolt  70  passes through a standard  74  with the bolt head bearing against the standard. The brackets  72   a ,  72   b  support a sleeve  76  between raised bosses  78  on the bolt so as to maintain its axial position. A threaded end  80  of bolt  70  engages a threaded block  82  attached to plate  66  so that rotation of bolt  70  will move plate  66  axially of the bolt. In this embodiment, locking of the position of hook  64  is assured by tightening of bolts  44 . 
     FIG. 9 illustrates another apparatus for positioning rear hook  64  of coupler  60 . The adjusting bolt  70  of FIG. 8 is replaced by a dual-acting hydraulic cylinder  84  mounting to plate  14  by a bracket  86  and pin  88  in a conventional cylinder mounting arrangement. An end  90  of piston rod  92  is connected to block  82  by a pin  94  extending through the end  90  and the block  82 . The bolts  44  of FIG. 8 are replaced by hydraulic locking cylinders  96  such as the type manufactured by Applied Power, Inc., Model ENERPAC RWH120. The advantage of this hydraulic system is that the coupler connections can now be remotely controlled and the hydraulic cylinders will exert a uniform pressure without loosening as might occur with threaded adjustors and fasteners. Further, the cylinders exert a pre-set force and avoid problems associated with under or over-torquing of threaded bolts. 
     The system of FIG. 9 can also be applied to the embodiment of FIGS. 1-3 by replacing the bolt  46  with a hydraulic cylinder such as shown at  84  and replacing bolts  44  by hydraulic cylinders such as shown at  96 .