Abstract:
Mobile construction equipment includes a hydraulically activated boom and operating stick for carrying two separately mounted construction tools. In an excavator, a bucket is mounted on the end of the stick in the conventional manner and adjacent the bucket there is rotatably mounted a second tool carrier or rack having an inner and outer end. Detachably mounted at the outer end of the rack is the second tool which travels with the mobile construction equipment. The rack is rotatable from a retracted position extending upwardly and along the stick to an extended position where the tool can be deployed for operational use.

Description:
TECHNICAL FIELD 
     This invention relates to tools for use on mobile construction equipment such as excavators. 
     BACKGROUND OF THE INVENTION 
     One of the more common pieces of powered equipment used in construction projects, logging operations, road building operations and the like is the mobile excavator typically having a rotatable cab containing the power unit mounted on wheels or caterpillar-like tracks. Extending upwardly and rotatable with the cab is the angled large boom member which can be moved up and down by actuating cylinders. Mounted at the upper end of the boom is the excavator stick member which can be pivoted in an up and down motion about the end of the boom by an actuating cylinder mounted on the boom. Mounted on the lower end of the excavator stick typically will be a single tool; most commonly an excavator bucket which is pivotally mounted and rotatable by way of an actuating cylinder connected to a linkage assembly. These machines have been commercially available for many years from manufacturers such as Caterpillar Tractor. 
     Typically these machines are most often operated with the bucket mounted at the end of the stick, it being a versatile implement for digging soil, scarifying the ground, and smoothing the ground. Other well-known tools can be mounted on the end of the stick as the need arises if a particular task must be performed. For example, in a logging operation where it is common for tasks to include road construction, brush clearing and timber harvesting, different functional tools will be used. Traditionally, for example, when an excavator is to be utilized for harvesting timber the excavator bucket would be removed and, with a typical coupling mechanism, a tree-felling head would be mounted on the end of the excavator stick. Again, such assemblies are well known and commercially available to permit multiple uses by the mobile excavator. 
     Oftentimes when in actual use where the excavator would be performing multiple functions, it was common to remove the bucket, attach the needed tool (such as a felling head, harvester-head, log grapple, brush cutter, or the like), and thereafter perform the particular task. Once the particular task was performed and the bucket needed again, additional time was needed to remove the attached tool and reinstall the bucket. This process is time consuming and reduces the productivity of the excavator. 
     When an excavator is used in the woods, the tool that was removed could be left a great distance from where the task was completed utilizing the second tool then attached to the stick. Such being the case, the mobile excavator would then have to return to the site where the first tool was left, taking even more time. Oftentimes, the tool could not be readily located and additional time was lost searching for it. 
     Since the bucket is the commonly used tool on the end of the stick it became apparent that what was needed was a rack assembly for carrying a second tool on the end of the stick which could be mounted so as to not interfere with the functioning of the bucket but which could be readily deployed when needed. 
     SUMMARY OF THE INVENTION 
     This invention is a tool carrier attachment or rack mounted adjacent the primary tool on the end of an excavator stick for carrying a second tool while the excavator is being operated. The rack is an elongated frame pivotally mounted on the stick and rotates in the same plane as the primary tool. At the distal end of the frame there is provided a tool mounting station adapted to support and carry a selected second tool. Means are provided for rotating the frame from a retracted position extending upwardly and opposite the boom stick to an extended position where the rack extends downwardly from the end of the stick. When the rack is in the retracted position the attached tool may be held in place while main the excavator tool is used as the primary operating tool. When the rack is in its extended position the attached tool can be deployed for operational use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a typical mobile excavator having the present invention mounted on the end of the boom stick. 
     FIG. 2 is also a side elevation view showing the bucket and tool rack with its attached tool mounted on the end of the stick. 
     FIG. 3 is another side elevation view showing the tool rack and tool in the retracted position. 
     FIG. 4 is a front elevation view illustrating the attachment and linkage structure for the rack at its inner end adjacent to the bucket. 
     FIG. 5 is a rear elevation view showing the connecting and linkage structure for the rack. 
     FIG. 6 is a side view illustrating the locking mechanism for holding the rack and tool in place when in the retracted position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring first to FIGS. 1-3, a typical commercially available excavator is generally indicated at  10 . Excavator  10  has a swivel-mounted cab  12  atop movable tread assemblies  14 . Extending upwardly from cab  12  is the boom assembly  16  which is moved through its normal range of motion by actuating cylinder  18 . At the top of boom  16  and extending downwardly therefrom is the hydraulically operated stick assembly  20 . Serving to move stick assembly  20  through its normal range of movement about pinned connection point  22  is actuating cylinder  24 . Stick assembly  20  is typical in that it is a box beam construction and has a pivotally mounted primary tool or rotatable bucket  26  attached at its outer end in the normal manner. Serving to rotate the bucket through its usual range of motion is hydraulic actuating cylinder  28  located on stick  20  in its common location along the top side of the stick. 
     Pivotably mounted at the outer end of stick  20  is an elongated rotatable carrier or rack generally indicated at  30 . Rack  30  is provided to support and carry a second tool generally indicated at  32  when excavator  10  is being used. A suitable connecting member  34  is interposed between rack  30  and tool  32 . In the embodiment depicted, a typical commercially available tree felling head is attached to rack  30  by way of a commercially available connecting member  34 . Difference types of connecting members may be utilized depending upon the particular type of second tool and they will preferably permit quick connections and disconnections to be made. 
     Rack  30  is rotated through its range of motion in substantially the same plane as bucket  26  by a pair of hydraulic cylinders, each indicated at  36  on either side of stick  20 , and each connected at its outer end to a linkage generally indicated at  38 . In the preferred embodiment, rack  30  has a body portion  40  comprising two opposed sidewalls each indicated at  42  and an outwardly extending beam member  44  attached to the ends of the sidewalls, at the end of which is attached connecting member  34  and the selected second tool. 
     At the inner ends of sidewalls  42 , rack  30  is connected to the end of stick  20  by the use of pins  46  which project outwardly from stick  20  and are typical of pins used for pinning a bucket onto the end of a stick except they are lengthened to serve as the pivotal attachment means for rack  30  as well as for bucket  26 . As previously noted, rack  30  can be rotated about pins  46  by cylinders  36  acting through linkages  38  from an extended position, such as shown in FIG. 2, to a fully retracted position such as shown in FIG.  3 . Linkages  38  are typical of a four-point linkage assembly and in the preferred embodiment include a second lengthened pin  48  on stick  20  spaced from pin  46 . Pins  48  also serve to connect stabilizing arms  50  to the stick assembly  20 . Spaced above pins  46  in sidewalls  42  are pinned connections  52  which serve to support linkage arms  54  for pivotal movement and to cause the rotational movement of rack  30 . Extending upwardly from pins  48  are pivotally mounted straps  56  to which, at approximately their midpoints, are pivotally attached the outer ends of cylinders  36 . At the end of straps  56 , at pin connection  58 , is the opposing end of arm  54 , the other end of which, as noted, is pinned to the rack sidewall. 
     Turning now to FIGS. 4 and 5, the lateral arrangement of the rack and bucket components in relation to stick  20  may be better seen and understood. The linkages  38  for operating the rack are closely spaced on the outside of the existing linkage for bucket  26  and inside sidewalls  42 . Bucket linkage assembly  51  further includes the rod-end of cylinder  28  being pinned to a turning arm  60  which is connected to the backside of bucket  26  at pinned connection  61  (see FIG.  3 ). As will be readily apparent to those skilled in the art the rack size will be adjusted to fit the particular dimensions of the excavator model on which the rack is mounted as well as the particular type of attached tool. 
     It will be recognized that a hydraulic and electrical power system will be provided along with a control system to give the operator in cab  12  the ability to control associated valving and operating sequences for movements of the cab, boom, stick, bucket, tool rack, and attached tools. Such systems are well known and can be modified by those with ordinary skill in the art to provide the hydraulics and controls for operation of the present invention. 
     Turning now to FIG. 6, the rack locking mechanism generally indicated at  62  will be described. Locking mechanism  62  is supported on a bracket  64  which is fixed to the side of the stick and extends roughly perpendicular thereto upwardly from a point adjacent to where the cylinders  36  are mounted. Bracket  64  straddles actuating cylinder  28  and has a platform  66  at the top. When rack  30  is in the retracted position, an outer portion of beam member  44  will rest atop platform  66 . A locking tab  68  is mounted on the end of the beam and extends downwardly therefrom at a location where it will overlay an edge of platform  66 . A small hydraulic cylinder  70  is mounted to the underside of platform  66  substantially in line with an aperture positioned within locking tab  68 . To lock the tool rack in place against stick  20  the operator activates hydraulic cylinder  70  causing a locking pin  72  on the end of the rod to extend into the aperture to lock the rack in place. When the tool rack is to be released for deployment, the hydraulic cylinder will retract pin  72 , thereby releasing the rack. 
     The operation of the present invention is very straightforward. In one preferred embodiment, a typical excavator will have a regular bucket mounted on the end of the stick. It is rotatable about the same axis as rack  30  as just described and is used for scooping dirt and the like. A preselected tool is mounted on the end of rack  30  and when the bucket is in use, the tool and rack will be rotated upwardly to a position out of the way and removed from the bucket. When necessary for travel and the like, the rack  30  can be locked in place in its retracted position. In addition, if the tool has grapple arms or the like which extend far enough they can be rotated inwardly so as to grip some part of the rack body so the tool is further held in place relative to the rack. 
     In the embodiment depicted, the rack mounted tool is a commercially available felling head and it can be utilized with the bucket, for example, for tree clearing and road building in forested areas. If the excavator operator first wishes to fall some timber, he will cause the bucket to be rotated upwardly toward the cab to a position out of the way of the tool rack as it is being deployed downwardly by actuating cylinders  36 . In FIG. 1, the operator has deployed the tool and rack downwardly to an extended operating position, and the tool has been released from the rack to be controlled by its the operator to perform its function. A feature in the preferred embodiment is illustrated in FIG. 1 where the bottom edge of rack  30  is contoured to fit the rear surface contour on the bucket. As will be understood, when the rack is deployed and the contoured shape of the rack nests within the contoured shape on the bucket, additional stability can be provided during operation. In the tree felling application, the felling head will be operated to cut and fall timber until such time as enough cleared area is established for road building. At that point the operator will retract the rack at least partially to a position out of the way of the bucket where it can be held in place hydraulically or, if the bucket is to be used for a lengthy period, the rack can be locked firmly in place utilizing locking mechanism  62 . The bucket is then utilized as the primary tool while the secondary, but still attached, tool is retracted and out of the way. This process can be repeated until the task is complete. Having an excavator with both tools traveling with it and each being operational upon command reduces changeover time and also keeps both tools together on the machine. 
     Having provided a description of a preferred embodiment many changes, alternatives, and variations may occur to those skilled in the art. All such changes and variations are intended to be included within the scope of the claims.