Abstract:
An excavator attachment alignment tool has cooperating tool body portions mounted to a cross tube defining an axis. The tool body portions are moveable relative to the cross tube to define a lower hook portion having surfaces to accommodate and support an engaged excavator attachment pin parallel with the tool axis, with the lower hook portion positionable for lifting engagement with the excavator attachment pin. Aligned cylindrical bushings are mounted to opposed surfaces of the body portions in alignment with the tool axis, with the cross tube engaged and extending generally between the bushings, with spacing of the cooperating tool body portions fixedly adjustable along the tool axis for accommodating a width of an associated excavator link or stick to which an excavator attachment is to be attached or removed; and wherein the tool body portions are mounted in a manner to resist independent rotation of either body portion.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of prior U.S. Provisional Application 62/197,798, filed on Jul. 28, 2015. The application is incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates to excavator attachments, and, in particular, to alignment tools for mounting and removing excavator attachments. 
       BACKGROUND 
       [0003]    Excavators and backhoes of conventional construction, e.g. as described in Horton U.S. Pat. No. 7,322,133, the complete disclosure of which is incorporated herein by reference, are known in the prior art. By way of example, and with reference to  FIGS. 12A and 12B  of the present application, a hydraulic excavator  100  has a chassis  114  with a cab  118  for the operator. Extending from the chassis  114  is a boom  122  pivotally attached to the chassis, and a dipper stick  124  pivotally attached at the outboard end of the boom  122 . The dipper stick  124  connected to the boom arm  122  is moved in and out by means of a hydraulic boom cylinder  126 . An excavator attachment, e.g., a multi-shank ripper excavator attachment or tool  112 , as taught in the Horton &#39;133 patent mentioned above, is removably connected to the dipper stick  124  at a stick pivot or pin  132  and to a 4-bar linkage  142  (connected to a hydraulic bucket cylinder  130 ) at a link pivot or pin  134 . 
         [0004]    As described above, and referring also to  FIG. 4 , excavator and backhoe attachments, such as buckets of different widths and types, e.g. ripper bucket  50  ( FIG. 6 ), ripper  52  ( FIGS. 8 ) and  112  ( FIGS. 12A and 12B ), and other tools, are typically connected to the machine stick  124  and to the link  142  by horizontal pins, i.e., stick or hinge pin  132  and link pin  134 . The stick pin  132  is held in place by engagement of a cross bolt  150  in aligned cross drilled hole  154  through the stick pin  132  and an associated stick pin locking collar  156 , and the link pin  134  is similarly held in place by engagement of a cross bolt  150  in aligned cross drilled hole  158  through the link pin  134  and an associated link pin locking collar  160 . The stick pin locking collar  156  and the link pin locking collar  160  are welded to the mounting plate (or “ear”) surface  166  of the excavator attachment. In turn, the cross bolts are secured in place by cooperating threaded nuts  152  at the opposite side of the collar  156 , thereby to resist rotation and movement of the pins  132 ,  134  relative to the excavator attachment (only one cross bolt  150  and threaded nut  152  are shown, by way of example). This arrangement is described and discussed below in more detail, e.g., with reference to  FIG. 4 ). 
         [0005]    In other implementations, e.g., referring to  FIG. 12B , a quick change coupler  164  may be used in place of the excavator attachment  128 , with the coupler  164  connected to the stick pivot pin  132  and link pin  134  by a set of two pins and an arrangement of hooks and locks that grab a second set of two pins mounted on the attachment. 
         [0006]    In still another implementation, mechanical and hydraulic “pin-grabber” couplers can also simplify the action of connecting the excavator attachment  112  to the stick  124  and link  142 . 
         [0007]    Changing excavator attachments  112  on an excavator or backhoe  100  without use of a quick change coupler  164  is recognized as being very difficult. For example, the operator must use a punch pin and a hammer to pound the linkage attachment pins  132 ,  134  into place and out of place. When pounding the pins into place for a new connection, it is very difficult to align each pin so that the retention cross bolt holes  154 ,  158  through the pins  132 ,  134  and their respective locking collars  156 ,  160  are aligned, in order to receive the cross bolts  150 . This method is known to be difficult, dangerous, messy, and to require two operators to accomplish it efficiently. Initially, to begin the process, the operator may gently rest the excavator attachment  112  on the ground; however, after a few short minutes, hydraulic valve spool leakage allows the combined weight of the stick  124  and boom  122  to cause the boom and stick to sag due to the hydraulic leakage drift. As a result, the entire weight of the stick and boom ends up resting on the linkage and attachment pins. During the changing operation, the operator tries to pound the pins  132 ,  134  out of place, but when one pin finally pops out, e.g. the stick pin  132 , the stick  124  drops, and the punch pin (not shown) becomes trapped in the bucket bore, pinched by the stick. The operator must then get back into the machine cab and lift the  124  stick with the hydraulic power, thereby seeking to free the punch. The operator then has to pound the link pin  134  out of place in a similar fashion. After the first excavator attachment (e.g. tool  112 ) has been disconnected, the operator must swing the linkage over while attempting to align the stick bosses  170  ( FIG. 4 , where only one is seen) with the attachment bosses  172  (again, only one is seen). Most of the time, the second attachment is not sitting on a flat portion of the ground and it is not fully square to the machine, so aligning the stick  124  to the attachment bosses  172  is very difficult. 
         [0008]    Once the stick and the replacement excavator attachment are aligned, the operator begins to pound the stick  132  into place from one side of the replacement attachment  112 ′, and then into the stick boss bore  170 , to complete the pivot. Again, because the stick  124  and boom  122  begin to slowly drift and sag lower due to hydraulic valve spool leakage, aligning the attachment pin bore  172  to the link bore  170  is very difficult. After the stick pin  132  is finally engaged into one side of the stick bore  170 , the pin must be pounded fully into place with a hammer until the end of the pin is visible on the opposite side of the attachment  112 ′. A cross bolt  150  is inserted to secure the pin  132  to the bucket  112 ′; however, it is very difficult to align the segments of locking bolt cross hole  158  (through the stick pin and through both sides of the stick pin locking collar  156 ) due to the weight of the stick  124  and boom  122  on the pin  132 , so the weight must again be lifted off the stick  124 , and the pin  132  rotated into alignment of the pin bolt hole segments so that the bolt  150  can be inserted. When the boom  122  and arm  120  are lifted, the weight of the attachment  112  again makes it difficult to rotate the pin  132 , thus requiring more pounding and difficulty. After assembly of the stick pivot pin  132  is complete, the link pin  134  can be pounded into place, typically with a little less difficulty, but the task is still considered to be difficult and dangerous. 
         [0009]    In fact, many equipment operators have suffered pinched, or even severed, fingers performing this operation. The task can also be very messy due to the grease covering the components. For these reasons, quick couplers  164  are recognized as a huge benefit to the industry. Additionally, use of quick couplers may allow some operators to change tools many times per day, so not having to pound pins into position is a huge benefit. The easier it is to change attachments, the more likely it is that an operator will change attachments frequently in order to employ the attachment best suited for the job being performed. In contrast, prior to use of quick change couplers, an operator often felt forced to continue to use a tool ill-suited for a segment of job, thereby to avoid the difficulty and downtime of making a change. As a result, having the ability to change attachments easily not only makes the job safer and faster for the operator, but it also makes the job more efficient and effective due to the increased frequency of use of the correct excavator attachment. 
         [0010]    There are, however, situations in which the use of a quick change coupler  164  is not advantageous. For example, in digging and ripping applications, where the shortest tip radius is often desirous, using a quick change coupler may not be the best alternative because the coupler increases the tip radius, thus reducing the overall breakout force of the machine, e.g., use of a quick connect coupler can reduce breakout force by between 10% and 15%. Similarly, in other dig-and-load and lifting situations, a quick connect coupler  164  adds significant weight at the end of the stick  124 , which decreases the payload that could otherwise be lifted safely. In addition, repeated lifting and lowering of a quick connect coupler increases fuel consumption and slows the cycle time of the digging operation, e.g. due to the extra weight. For example, a typical quick change coupler sized for use with 80 mm attachment pins weighs almost 1,000 pounds. 
         [0011]    Hydraulic versions of pin-grabber couplers, e.g. as compared to mechanical versions, allow attachment changes to be made by an operator while remaining in the cab. However, the additional hydraulic valve and hydraulic plumbing of these couplers increases their complexity. These couplers and their plumbing components are also expensive, and introduce another possible source for contaminants in the hydraulic system. By way of example only, a typical hydraulic coupler for an excavator with 80 mm attachment pins may cost may cost as much as $8,000, not including the hydraulic kit, which can add another $4,000. The cost of a typical mechanical version of a pin-grabber coupler is, e.g., approximately $6,000. 
       SUMMARY 
       [0012]    According to one aspect of the disclosure, an excavator attachment alignment tool comprises: a first alignment tool body portion and a cooperating second alignment tool body portion, the first and second cooperating alignment tool body portions mounted to a cross tube; the cross tube defining an alignment tool axis; and the cooperating alignment tool body portions being moveable relative to the cross tube into engagement to define a tapering, lower hook portion having opposed, spaced surfaces to accommodate and support an engaged excavator attachment pin in a position parallel with the alignment tool axis, the tapering, lower hook portion being positionable for lifting engagement with the excavator attachment pin, a pair of axially aligned cylindrical bushings mounted to opposed surfaces of the cooperating alignment tool body portions in alignment with the alignment tool axis, the cross tube engaged with and extending generally between the axially aligned cylindrical bushings; wherein, spacing of the cooperating alignment tool body portions, with the cylindrical bushings mounted thereto, is fixedly adjustable along the alignment tool axis for accommodating a width of an associated excavator link or excavator stick to which an excavator attachment is to be attached or to be removed; and wherein, the pair of cooperating alignment tool body portions is mounted in a manner to resist independent rotation of either of the pair of alignment tool body portions. 
         [0013]    In preferred implementations of this aspect of the disclosure, at least one end of the cross tube is fixedly attached to a body portion of the pair of cooperating alignment tool body portions. The spacing of the cooperating first and second alignment tool body portions defines a first width between opposed inner surfaces of the cooperating first and second alignment tool body portions equal to a second width of the cooperating first and second alignment tool body portions at the lower hook portion. The excavator attachment alignment tool further comprises at least one member for locking axial positioning of at least one alignment tool body portion of the pair of cooperating alignment tool body portions relative to the cross tube. The member for locking axial position of the at least one alignment tool body portion is a locking collar. The opposed cylindrical bushings are sized for engagement within openings at opposite ends of an excavator stick boss or at opposite ends of an excavator link boss. Preferably, the excavator attachment alignment further comprises a pair of sleeve bushings, each sleeve bushing having an inner surface of diameter sized to be received over an outer surface of one of the cylindrical bushings in supporting engagement, and each sleeve bushing having an outer surface of diameter selected to be received within the openings at opposite ends of the excavator stick boss or at opposite ends of the excavator link boss in supporting engagement, thereby to accommodate use of the excavator attachment alignment tool with excavators having openings at opposite ends of the excavator stick boss or at opposite ends of the excavator link boss of a relatively greater diameters compared to the cylindrical bushings. The cooperating alignment tool body portions further comprise one or more guide plates mounted for sliding interengagement between the alignment tool body portions in a manner to resist independent rotation of either alignment tool body portion. The alignment tool body portions and the cross tube define cooperating interengageable structure for resisting independent rotation of either body portion. The lower hook portion is tapered toward the tip. With the excavator alignment tool engaged within the openings at opposite ends of the excavator stick boss or at opposite ends of the excavator link boss, and with an excavator attachment suspended by the hook portion of the excavator attachment alignment tool engaged with an excavator attachment pin having an excavator attachment pin axis, the excavator alignment tool axis and the excavator attachment pin axis engaged by the lower hook portion are disposed parallel to each other and disposed in alignment with the center of gravity of the suspended excavator attachment. 
         [0014]    According to another aspect of the disclosure, an excavator attachment alignment tool is configured and arranged, when in use, to accommodate and support an engaged excavator attachment pin, to hold the excavator attachment pin with its axis parallel to an excavator linkage pin axis, and to hold an attachment longitudinal center plane co-planar with a linkage stick longitudinal center plane. 
         [0015]    In preferred implementations of this aspect of the disclosure, the excavator attachment alignment tool, with an excavator attachment suspended from the alignment tool, the attachment pin axis and the excavator linkage pin axis are parallel, and define a second lateral plane that includes the center of gravity of the excavator attachment, thereby relieving radially-directed forces impeding insertion and removal of the connecting excavator attachment linkage pins and pin locking bolts. 
         [0016]    According to still another aspect of the disclosure, a method for mounting and dismounting an excavator attachment using an excavator attachment alignment tool of the disclosure comprises the steps of: with an excavator machine running, lifting a presently mounted excavator attachment off the ground; extending or retracting a bucket cylinder to position the presently mounted excavator attachment with its center of gravity directly below a stick pivot; with the excavator attachment link pin now under little or no pressure, unbolting and pushing the link pin from the excavator link bore; swinging the link out of the way and inserting the attachment link pin back into the link bore of the first excavator attachment with no link; connecting the upper end of the excavator attachment alignment tool into one end of the link; positioning a lower hook portion of the excavator attachment alignment tool to generally encircle the first excavator attachment link pin; securing the excavator attachment alignment tool together with a proper width matching the width of the link; retracting the bucket cylinder to the first excavator attachment until its center of gravity is positioned directly below the link, with the excavator attachment link pin now being parallel to the excavator link pin bore, and the attachment center plane being aligned with the link center plane, and with the link vertical; with the pin under no pressure, unbolting and disengaging the stick or hinge pin; 
         [0017]    inserting the stick or hinge pin into the link pin bore of the second excavator attachment; lowering the boom and moving the stick outward to lower the first excavator attachment to the ground, and releasing the excavator attachment alignment tool from the attachment pin of the first excavator attachment, with the second excavator attachment link pin now being parallel to the excavator link pin bore and the second excavator attachment longitudinal center plane now being aligned with the longitudinal excavator link center plane; engaging the excavator attachment alignment tool lower portion with the link pin of the second excavator attachment, and lifting the boom so that the second excavator attachment hangs freely; retracting the bucket cylinder so that the stick bosses of the second excavator attachment are positioned near the stick end; engaging the attachment pin into the bosses of the second excavator attachment and the stick boss by swinging or rocking the second excavator attachment into an easy insertion position, and bolting the attachment pin into place; extending the bucket cylinder so that the excavator attachment alignment tool is released from the link pin and the link boss is close to the second attachment link boss; removing the excavator attachment alignment tool; and inserting the link pin by swinging the excavator attachment fore and aft by hand, inserting the pin locking bolts, and securing the nut. 
         [0018]    The excavator attachment alignment tool of this disclosure allows the excavator or backhoe operator to change excavator attachments without the use of a quick change coupler, and without having to deal with the difficulty of aligning linkage pins and pin locking bolts, and the associated heavy pounding required for placement and removal of stick and link pins. 
         [0019]    The excavator attachment alignment tool of this disclosure also allows the operator to change excavator attachments without the cost, use and weight a quick change coupler, and without having to deal with heavy pin pounding and the difficult task of aligning the stick and link pins with locking collar cross bore segments for securement with threaded cross bolts and nuts. 
         [0020]    The excavator attachment alignment tool of this disclosure allows the operator to employ a simplified method for removing an excavator attachment, and then mounting a new excavator attachment, regardless of the position or the flatness of the surrounding ground surface. 
         [0021]    Changes of excavator attachments or tools can be completed with the excavator attachment alignment tool of this disclosure without the difficulties of hydraulic valve spool leakage drift mentioned above. Also, the excavator attachment is secured directly to the stick linkage, without an additional piece of equipment between stick linkage and the excavator attachment, so there is no reduction in breakout force. There is also no extra weight to reduce the amount of payload that can be lifted, or that can waste energy each time the boom is lifted. 
         [0022]    Finally, by way of example only, the typical cost of an excavator attachment tool of this disclosure, e.g. for the 80 mm pin size, is approximately $1,060, which is less than about 20% of the cost of a mechanical quick change coupler. 
         [0023]    The details of one or more implementations of the invention are set forth in the accompanying drawings and in the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0024]      FIG. 1  is an exploded front view of the components of an excavator attachment alignment tool of the disclosure, including a first (left) alignment tool body portion, a second (right) alignment tool body portion, and a locking collar; 
           [0025]      FIG. 2  is a right side view of the excavator attachment alignment tool assembly of  FIG. 1 , with a hook portion formed in the lower region; and 
           [0026]      FIG. 3  is an exploded isometric view of the components of the excavator attachment alignment tool of  FIG. 1 . 
           [0027]      FIG. 4  is an exploded isometric view of the components of an excavator attachment, in this case a bucket, being supported by the excavator attachment alignment tool of  FIG. 1 , suspended from the excavator link boss. The stick is shown unattached, with the stick pin removed. For purposes of comparison and understanding, a second excavator attachment alignment tool of the disclosure is shown in dashed line, with its components (first (left) alignment tool body portion, second (right) alignment tool body portion, and locking collar) in unattached, exploded isometric view position. 
           [0028]      FIG. 5  is a front view of excavator attachment of  FIG. 4 , hanging from the hook portion of an excavator attachment alignment tool of the disclosure, suspended from the excavator link. 
           [0029]      FIG. 6  is a left side view of the excavator stick and linkage, with the link pivot disconnected, and the excavator attachment (a bucket) hanging from the stick pivot, with the bucket center of gravity directly below the stick pivot. 
           [0030]      FIG. 7  is a left side view of the excavator stick and linkage, with the stick pivot unattached, and the excavator attachment (the bucket) hanging from the hook portion of the excavator attachment alignment tool of the disclosure connected to the link pivot, with the bucket center of gravity directly below the link pivot, and in alignment with the excavator attachment pin axis. 
           [0031]      FIG. 8  is a left side view of the excavator stick and linkage, with the stick pivot unattached, and an excavator attachment (a ripper) hanging from the hook portion of an excavator attachment alignment tool of the disclosure connected to the link pivot, with the ripper center of gravity directly below the link pivot, and in alignment with the excavator attachment pin axis 
           [0032]      FIG. 9  is a left side view of the excavator stick and linkage with the link unattached and the excavator attachment (the ripper) hanging from the stick pivot with the ripper center of gravity directly below the stick pivot. 
           [0033]      FIG. 10  is an exploded front view of the components of an excavator attachment alignment tool of the disclosure with diameter adjustment bushings; and  FIG. 11  is a right side view of the excavator attachment alignment tool assembly of  FIG. 10  with a hook portion formed in the lower region. 
           [0034]      FIG. 12A  is a prospective view of a hydraulic excavator with an excavator attachment arrangement fitted, e.g., with a multi-shank ripper excavation attachment, and  FIG. 12B  is prospective view of a hydraulic excavator fitted with a quick connect coupler, to which is mounted, e.g., a multi-shank ripper excavation attachment, all conventional and known in the prior art. 
       
    
    
       [0035]    Like reference symbols in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0036]    Referring to  FIGS. 1, 2 and 3 , an excavator attachment alignment tool  10  of the present disclosure consists of a first (or left) body portion  12  and second (or right) body portion  14 . A first cylindrical bushing  18  is mounted to an inner surface  13  of the first body portion  12 , with the cylindrical bushing  18  defining a pivot bore  19 . A second cylindrical bushing  22  is mounted to an opposed inner surface  15  of the second body portion  14 , with the cylindrical bushing  22  defining a pivot bore  23 . In this implementation, a cross tube  20  is secured, e.g. by welding, in the pivot bore  19  of cylindrical bushing  18 . 
         [0037]    The excavator attachment alignment tool  10  is assembled by sliding the free end  21  of cross tube  20  extending from the first body portion  12  through the pivot bore  23  of the cylindrical bushing  22  mounted to the opposed inner surface of the second body portion  14 . A locking collar  26  is then slid onto the external exposed end  21  ( FIG. 5 ) of cross tube  20 . The locking collar  26  (which may be a commercially available lock ring) is spring loaded and provides a locking function that resists axial movement of the second body portion  14  outwardly along the exposed end of the cross tube or shaft  20  when the locking collar  26  is engaged. 
         [0038]    The first and second body portions  12 ,  14  are then slid together along the cross tube  20 . When adjustably assembled, the bottom regions  1 ,  2  of the respective first and second body portions  12 ,  14  of the alignment tool  10  cooperatively form a lower hook portion  32 , and guide plates  34 ,  36  welded to rear (outer) surface  11  of the first body portion  12  serve to engage and hold the first and second body portions  12 ,  14  when the two body portions are slid together, thereby resisting relative rotation. 
         [0039]    Commercially, different brands of excavator attachments having a common pin diameters may typically may have different link widths. The sliding adjustable inter-engagement of the first and second body portions  12 ,  14  of the excavator attachment alignment tool  10  of this disclosure thus permits positioning of the engaged body portions at variable combined width dimensions, W, thereby to accommodate a wide range of linkage widths, while also providing a hook of the proper width dimension. 
         [0040]    Referring still to  FIGS. 1, 2 and 3 , the cross tube  20  of the excavator attachment alignment tool  10  of the disclosure is welded to the first or left side body segment  12 . A relatively larger diameter cylindrical bushing  18  mounted on the tube has a diameter corresponding to the diameter of the smallest pin diameter in the excavator size class. The second or right side body portion  14  has a welded bushing  22  of similar, relatively large outside diameter. An excavator attachment alignment tool  10  of the disclosure is dimensioned for use with a pin having, e.g., an 80mm diameter for the class size shown, but can be adapted for use with excavator attachments having link pins and stick or hinge pins of other, relatively larger dimension. 
         [0041]    Referring briefly to  FIGS. 10 and 11 , by way of example only, adjustment bushings  42 ,  44 , each having a wall of thickness, T, e.g. 5 mm, and an outside diameter, OD, e.g. 90 mm, can be slipped over the 80 mm welded bushings  18 ,  22 , respectively, at each end of the cross tube  20 , thereby to adjust the excavator attachment alignment tool  10  for use with a 90 mm size class machine (i.e., with an excavator attachment with link and stick or hinge pins having a 90 mm outer diameter). As a result, depending on the class size of the excavator, the excavator attachment alignment tool  10  of the disclosure can be quickly adapted for use, e.g., with 80 mm, 90 mm, 100 mm and 110 mm diameter link and stick or hinge pins, by simply sliding on adjustment bushings of the appropriate dimension. The inside radius, R, of the lower hook portion  32  typically corresponds to the smallest diameter pin size, i.e. in the case shown, 80 mm, at its base, but the opposed hook wall surfaces thereabove flare out to a relatively larger distance, D, apart, i.e. relatively greater than  2 R, thereby to accommodate and align link and stick or hinge pins  132 ,  134  of relatively greater diameter. 
         [0042]    The width, W L , at the lower end portion of the hook is the same as the width, W, between the opposed inner surfaces  11 ,  13  inside of the upper portions of the vertical plates (see, e.g.,  FIG. 5 ). When the alignment tool  10  is in use, the inner opposed surfaces  13 ,  15  of the respect first and second body portions  12 ,  14  are tightly engaged at opposed side surfaces of the link (or stick). The hook shape is such that an excavator attachment is easily “hooked” or picked up by engaging the lower hook portion  32  of the excavator attachment alignment tool  10  underneath an excavator attachment pin  132  or  134 . The excavator attachment pin slides easily into the curve of the hook  32  of the excavator attachment alignment tool  10 , and then aligns the excavator attachment so that the axis of the excavator attachment pin is axially aligned with the axis of the cross tube  20  of the excavator attachment alignment tool, and thus axially aligned with the link pin bore  174  of the excavator link  142  ( FIG. 6 ). In this manner, the excavator attachment pin is arranged parallel to the link pin bore and the excavator attachment is aligned side-to-side in position for engagement and mounting to the excavator arm such that the excavator attachment longitudinal center plane is disposed in alignment with the longitudinal link center plane. As a result, the procedure for changing from a first excavator attachment (e.g., a Multi-Ripper bucket  50 ,  FIGS. 4, 6 and 7 ) to a second excavator attachment (e.g., a non-bucket Multi-Ripper  52 ,  FIGS. 8 and 9 ) is relatively simply achieved. 
         [0043]    As described above, the excavator attachment alignment tool  10  consists of a first or right portion  12  and a second or left portion  14 , with an upper end configured for secure engagement with and mounting upon the stick boss  170  or the link boss  174  of the excavator arm in the manner of the stick or hinge pin  132  or the link pin  134 . The lower end portion of the alignment tool  10  has the form of a tapered hook  32  that assists in the dismounting (i.e., “dropping off”) of the “old” excavator attachment already in use, and/or the mounting (i.e., “picking up”) of a “new” excavator attachment. The excavator attachment alignment tool  10  allows the operator to change the stick or hinge pin  132  and link pin  134 , one at a time, creating a sequence of conditions for each pin such that the pin force is low, and the excavator attachment is off the ground. The pin forces are low at the time of each pin insertion or removal because the alignment tool  10  allows the center of gravity (CG) of the excavator attachment to be in a position that relieves the force from the joint. Since the pin placement operations occur while there is a reduced level of force or load upon the link pin  134  or stick or hinge pin  132 , the pin can be pushed in or removed relatively more easily (i.e., with relatively less force), and it is easier (again, with less force) to rotate the pins in order to align the cross bolt hole segment of the pin  132 ,  134  with the cross bolt hole segments of the respective locking collars  156 ,  160  for insertion of the locking bolts  150 . 
         [0044]    Also, as discussed above, a single model of the excavator attachment alignment tool  10  of the disclosure can be adapted for use across a range of several different excavator attachment pin diameters. For example, an excavator attachment alignment tool  10  of the disclosure can be used with a range of different excavator attachments, as long as the excavator attachment pin diameter is within the indicated range. Many excavators within a single size class have excavator attachments pins of a common diameter. 
         [0045]    For example, excavator attachments such as Hitachi EX200, Cat 320, Case CX160 or CX210, John Deere 200, Komatsu PC200, and Linkbelt LX160 all have 80 mm pins for the excavator attachment linkage hook-up. As a result, for all of these excavator machines, a single model of the excavator attachment alignment tool  10  of this disclosure can be used without additional components. In addition, excavator machines having 90 mm, 100 mm or 110 mm diameter excavator attachment pins can also be adapted for use with the same excavator attachment alignment tool by the addition of sleeves or bushings of appropriately different diameters. Therefore, one model size of the excavator attachment alignment tool 10 of the disclosure can be used for excavator attachments with pin sizes from 80 mm up to 110 mm (i.e., the pin diameter range encompassing all mid-sized 40,000 to 110,000 pound excavator machine class sizes). A smaller model of the excavator attachment alignment tool of the disclosure, with sleeves having different diameters can accommodate 45 mm, 56 mm, 66 mm and 70 mm excavator attachment pins, e.g. as found in smaller excavators and backhoes in the 11,000 to 40,000 pound range). As a result, only two models of the excavator attachment alignment tool 10 of this disclosure are sufficient to cover excavators and backhoes from 11,000 pounds up to larger excavators weighing 110,000 pounds. By way of example only, the larger size excavator attachment alignment tool weighs approximately 55 pounds, while the smaller excavator attachment alignment tool weighs approximately 35 pounds. 
         [0046]    Mini-excavators and backhoes that have excavator attachments with pin diameters less than 45 mm are typically easier to change, e.g. due to the relatively reduced weight of the excavator attachments. As a result, an excavator attachment alignment tool is less likely to be needed in that size range. Larger excavators having attachment pins with diameters greater than 110 mm would generally require an excavator attachment alignment tool that would be too heavy to lift manually. 
         [0047]    We will now describe a typical procedure for use of the excavator attachment alignment tool  10  of the disclosure with one operator, and one helper for dismounting and mounting an excavator attachment: 
         [0048]    Step  1 : With the excavator machine  100  running, and the operator in the cab  118  to operate the excavator machine hydraulic controls, the presently mounted excavator attachment (e.g. an excavator bucket  50 ) is lifted about a foot off the ground. The bucket cylinder  130  is then extended or retracted so that the center of gravity (CG) of the currently mounted excavator attachment is directly below the stick pivot  132 . 
         [0049]    Step  2 : With the excavator attachment link pin  134  now under no pressure, the helper unbolts and pushes the link pin  134  out of the excavator link bore  170 . The link  142  is next swung out of the way, and the attachment link pin  134  is inserted back into the link bore  170  of the first excavator attachment  50  with no link (see, e.g.,  FIG. 6 ). 
         [0050]    Step  3 : The helper slides free end  21  of the cross tube  20  and then the cylindrical bushing  18  of the first or left body portion  12  of the excavator attachment alignment tool  10  into one end of the link  174 , and then slides the second or right portion  14  of the excavator attachment alignment tool onto the free end  21  of the cross tube  20  and into the opposite end of the link boss  174 , e.g. as shown  FIG. 4 ). The helper positions the lower hook portion  32  of the excavator attachment alignment tool  10  to generally encircle the first excavator attachment (link) pin  134 , and then slides the locking collar  26  onto the end  21  of the cross tube  20 , thereby to secure the first and second hook portions  12 ,  14  of the excavator attachment alignment tool  10  together with proper width, W, matching the width of the link  142  (see  FIG. 5 ). 
         [0051]    Step  4 : The operator next retracts the bucket cylinder  130 , thus lifting the first excavator attachment  50  until the center of gravity, CG, of the excavator attachment is positioned directly below the link  134 , and the link  142  is vertical. Then, with the pin  134  under no pressure (see  FIG. 7 ), the helper can easily unbolt and disengage the stick or hinge pin  132 . 
         [0052]    Step  5 : The helper then puts the stick or hinge pin  132  into the link pin bore  170  of the second excavator attachment (e.g., a ripper  52 ). 
         [0053]    Step  6 : The operator then lowers the boom  122  and moves the stick  124  outward to lower the first excavator attachment  50  to the ground and unhook the excavator attachment alignment tool  10  from the attachment pin  132  of the first excavator attachment  50 . 
         [0054]    Step  7 : The operator then engages the excavator attachment alignment tool  10  lower hook portion  32  with the link pin  132  of the second excavator attachment  52 , and lifts the boom  122  so that the second excavator attachment is hanging freely. (The second excavator attachment pin  134  is now parallel and centered, e.g., see  FIG. 8 .) The operator then retracts the bucket cylinder  130  so that the stick bosses  170  of the second excavator attachment  52  are positioned near the stick end  124   
         [0055]    Step  8 : The helper then engages the attachment pin  134  into the bosses  172  of the second excavator attachment  52  and the stick boss  170  by swinging or rocking the second excavator attachment  52  (with his hand), into an easy insertion position. He then bolts the attachment pin  134  into place. 
         [0056]    Step  9 : The operator then extends the bucket cylinder  130  so that the excavator attachment alignment tool  10  is unhooked from the link pin  134  and the link boss  174  is close to the second attachment link boss  176  and the helper removes the excavator attachment alignment tool  52  (see  FIG. 9 ) 
         [0057]    Step  10 : The helper finally inserts the link pin  134  by swinging the excavator attachment  52  fore and aft with his hand, inserts the pin locking bolts  150 , and secures the nut  152 . The procedure is then complete! 
         [0058]    The entire process described above can also be completed by the operator working alone; however, this would require that the operator make several trips in and out of the cab. The excavator attachment alignment tool  10  of the disclosure works easily because when the first and second portions  12 ,  14  of the excavator attachment alignment tool  10  are pushed together on the link  142  (or the stick  124 ), the inner diameter of the hook  32  is the same width or diameter as the link pin  134  or stick or hinge pin  132 ), thus automatically positioning the excavator attachment  50  or  52  with the attachment pins  132 ,  134  disposed parallel to each other, and the excavator attachment is centered properly on the machine, with the longitudinal center plane of the excavator attachment is in alignment with the longitudinal center plane of the link  142  (or the stick  124 ). Due to this positioning of the center of gravity of the excavator attachment, the excavator attachment alignment tool  10  allows the pins  132 ,  134  to be relieved of pressure, thus allowing insertion, removal, and rotational alignment of the pin bolts  150  to be easier. 
         [0059]    Also, referring to  FIG. 7 , the excavator attachment alignment tool  10  is configured and arranged, when in use to accommodate and support an engaged excavator attachment pin (link pin or pivot  134 ), to hold the excavator attachment pin with its axis parallel to an axis of the excavator linkage pin (cross tube  23 ), with an attachment lateral center plane including the excavator attachment pin axis disposed co-planar with a linkage stick lateral center plane including the excavator linkage pin axis. 
         [0060]    A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the excavator attachment alignment tool  10  can be used on the stick pivot  170 , as well as on a link pivot  174 . 
         [0061]    Also, other means for keeping the alignment tool body portions  12 ,  14  from rotating can be employed. For example, the cross tube  20  may be splined with mating grooves inside the opposite halves, thereby to resist relative rotation. The excavator attachment alignment tool hook can be manufactured from round stock bars, rather than plates. In use, the excavator attachments alignment tool can be reversed, e.g., so that the cross tube  20  is connected to the excavator attachment and the alignment tool hook portions  12 ,  14  straddle the link pin  134  and engage onto the ends of the attachment pin in the link bore. 
         [0062]    Accordingly, other embodiments are within the scope of the following claims.