Abstract:
A closure member is pivotally connected with respect to a hydraulically operated bucket. A link member is pivotally connected to a hydraulically operated arm segment. The link member is also pivotally connected to the closure member. The closure member and the hydraulically operated bucket are connected for simultaneous pivotal movement in opposite directions with respect to each other.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to construction equipment such as backhoes and, more particularly, to a movable thumb or closure element, which operates in conjunction with a hydraulically controlled bucket. While the present invention is described in terms of a backhoe bucket, the present invention may be utilized with other construction equipment having a pivotally mounted bucket for operation on a hydraulic arm. 
     2. Description of the Prior Art 
     Most backhoes are equipped with a hydraulically pivotal bucket. If only the backhoe bucket is used, it is very difficult to pick up objects such as a tree because if the object or tree is not perfectly balanced on the bucket, then the object or tree will tend to fall off. As well, it may be difficult to grasp objects such as trees for lifting or pulling purposes. 
     Because of this problem, a fixed thumb or hydraulic control thumb may be attached for use with a bucket. As used herein a thumb is a closure element of some type against which the bucket may be rotated for grasping purposes. A movable thumb in accord with the present invention is discussed hereinafter. 
     The disadvantage of a fixed thumb or closure element is that the fixed thumb must be pushed against the object, such as a tree by lowering the lifting boom and moving the stick boom of the backhoe toward the object. Then the bucket is rotated against the thumb. Another problem with a fixed thumb is that the fixed thumb may interfere with other operations of the bucket. The fixed thumb does not permit wide range of different size objects to be manipulated. The fixed sum is also not in the right position to be of any use to pick up a pile of loose dirt or other material. 
     The prior art hydraulically operated movable thumb requires the movable thumb to be moved toward the object, whereupon the bucket is rotated against the thumb. This action requires the operator&#39;s use of multiple levers, which is slow and over time becomes tedious. The operation may also be complex. The hydraulically operated thumb and bucket operation may require the operator to use three levers simultaneously for grasping and lifting. The limited range of movement of the hydraulically operated thumb limits the variation in size of the objects, such as trees or poles, which can be manipulated by the backhoe. 
     The above cited prior art does not disclose a movable thumb that permits the operator to use a single lever to control pivotal motion of the backhoe bucket and the movable thumb simultaneously. The solutions to the above described and/or related problems have been long sought without success. Consequently, those skilled in the art will appreciate the present invention that addresses the above and other problems. 
     SUMMARY OF THE INVENTION 
     It is a general purpose of the present invention to provide an improved movable thumb assembly. 
     An object of the present invention is to provide a movable thumb assembly which operates in conjunction with a pivotal bucket. 
     An advantage of the present invention is that an operator can control both the bucket and the movable thumb utilizing only one hydraulic lever control. 
     A movable thumb assembly for use with a hydraulically operated bucket may comprise a first hydraulically operated arm segment, a second hydraulically operated arm segment connected to the first hydraulically operated arm segment, and a bucket pivot connection which pivotally connects the hydraulically operated bucket to the second hydraulically operated arm segment. 
     A moveable thumb, i.e., a closure member is pivotally connected with respect to the hydraulically operated bucket. 
     A link member is pivotally connected to the second hydraulically operated arm segment. The link member is also pivotally connected to the closure member. The closure member and the hydraulically operated bucket are connected for pivotal movement in opposite directions with respect to each other. 
     The movable thumb assembly may further comprise a bucket bracket mounted to the hydraulically operated bucket for providing the pivotal connection between the closure member and the hydraulically operated bucket. 
     In one embodiment, the bucket bracket may preferably be positioned adjacent to or in the vicinity of the bucket pivot connection. 
     The movable thumb assembly may further comprise a first link member pivotal connection for providing that the link member is pivotally connected to the second hydraulically operated arm segment, a second link member pivotal connection for providing that the link member is pivotally connected to the closure member, and a closure member pivotal connection for providing that the closure member is pivotally connected with respect to the hydraulically operated bucket. 
     In one embodiment, the first link member pivotal connection, the second link member pivotal connection, and the closure member pivotal connection each comprise removable pins, whereby the link member and the closure member are removable from the hydraulically operated bucket. 
     In one embodiment, the closure member comprises a closure member axial shaft portion. In this embodiment, the bucket bracket is pivotally connected to the shaft. 
     The second link member pivotal connection may be positioned further from the bucket pivot connection along the closure member axial shaft than the bucket bracket. 
     In one embodiment, the closure member comprises a length which is approximately equal to a length of an open end of the hydraulically operated bucket. However, the closure member could be longer or shorter than the open end of the hydraulically operated bucket. 
     In one embodiment, the closure member and the link member are mounted with removable pins, which have fasteners, latches, or fastening mechanisms to keep them in position during operation. By removing the removable pins, the closure member and the link member are removable from the hydraulically operated bucket. 
     In another embodiment, the present invention provides a method for mounting a movable thumb assembly for use with a hydraulically operated bucket. 
     The method may comprise steps such as pivotally connecting a closure member with respect to the hydraulically operated bucket, pivotally connecting a first portion of a link member to the second hydraulically operated arm segment, and pivotally connecting a second portion the link member to the closure member whereby the closure member and the hydraulically operated bucket are connected to pivot in opposite directions with respect to each other. 
     The method may further comprise mounting a bucket bracket to the hydraulically operated bucket for providing the pivotal connection between the closure member and the hydraulically operated bucket. 
     The method may further comprise mounting the bucket bracket adjacent to the bucket pivot connection. 
     The method may further comprise steps such as providing a first link member pivotal connection for implementing that the link member is pivotally connected to the second hydraulically operated arm segment, providing a second link member pivotal connection for implementing that the link member is pivotally connected to the closure member, and providing a closure member pivotal connection for implementing that the closure member is pivotally connected with respect to the hydraulically operated bucket. 
     In one embodiment the method may comprise providing that the first link member pivotal connection, the second link member pivotal connection, and the closure member pivotal connection each comprise removable pins, whereby the link member and the closure member are removable from the hydraulically operated bucket. 
     In one embodiment, the method may further comprise providing that the closure member comprises a closure member axial shaft and providing that the second link member pivotal connection is positioned further from the bucket pivot connection along the closure member axial shaft than the bucket bracket. In this embodiment, the method may comprise providing that the bucket bracket is pivotally connected to the closure member axial shaft. 
     The method may comprise providing that the closure member comprises a length which is approximately equal to a length of an open end of the hydraulically operated bucket. 
     The method may comprise mounting the closure member and the link member utilizing removable pins, whereby the closure member and the link member are removable from the hydraulically operated bucket. 
     In another embodiment, the movable thumb assembly may comprise a bucket bracket mounted to the hydraulically operated bucket, a closure member pivotally connected to the bucket bracket, and a link member. 
     A link member first pivotal connection pivotally connects the link member to the second hydraulically operated arm segment. A link member second pivotal connection pivotally connects the link member to the closure member. 
     In this embodiment, the bucket bracket is positioned closer to the bucket pivot connection then the link member second pivotal connection. 
     In this embodiment, the link member first pivotal connection is positioned on or adjacent to one end portion of the link member and the link member second pivotal connection is positioned on an opposite end portion of the link member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts and wherein: 
         FIG. 1  is a side elevational view of a backhoe with the moveable thumb and bucket in an open position, in accord with one possible embodiment of the present invention. 
         FIG. 2  is a side elevational view of a backhoe with the moveable thumb and bucket in a closed position, in accord with one possible embodiment of the present invention. 
         FIG. 3  is a top elevational view, partially in hidden lines, which shows a bucket bracket mounted to the backhoe bucket, in accord with one possible embodiment of the present invention. 
         FIG. 4  is a top elevational view, partially in hidden lines, which shows a movable thumb, in accord with one possible embodiment of the present invention. 
         FIG. 5A  is a top elevational view, partially in hidden lines, which shows two link members that pivotally connect the backhoe arm to the movable thumb, in accord with one possible embodiment of the present invention. 
         FIG. 5B  is a top elevational view, partially in hidden lines, which shows a single link member that pivotally connects the backhoe arm to the movable thumb, in accord with one possible embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The presently described backhoe with movable thumb provides a simplified grasping action, which operates more quickly and effectively than prior art backhoes. 
       FIG. 1  and  FIG. 2  show a generalized backhoe arm and backhoe bucket to which movable thumb mechanism  10  may be detachable you mounted. It will be appreciated that the present invention may be utilized with other construction equipment, which comprises a pivotally mounted bucket for use on a hydraulic arm. 
     The backhoe arm may typically comprise components such as lift boom  12 , stick boom  14 , hydraulic cylinders  16 A and  16 B, and hydraulic cylinder  18 . These components may be utilized to operate a backhoe bucket  20  by positioning backhoe bucket  20  where needed and moving backhoe bucket  20  as desired. 
     In  FIG. 1 , backhoe bucket  20  and movable thumb  22  are in the open or dumping position. Accordingly, thumb  22  rotates away from the open end of bucket  20  towards the backhoe arm. 
     In  FIG. 2 , movable thumb  22  and backhoe bucket  20  are rotated relative to each other to close the gap there between, which enables dirt to be pushed into the bucket or enables clamping onto a tree or other object. 
     Movable thumb mechanism  10  may be permanently mounted or may be removable as desired. In this embodiment, movable thumb mechanism is pin mounted so as to be easily removable, as discussed in more detail hereinafter. 
     Bucket bracket  24  may in one embodiment be fixed to bucket  20  whereupon bucket bracket  24  rotates with bucket  20 , as controlled by the operator utilizing a single hydraulic control. Bucket bracket  24  may preferably mounted near a hinge such as hinge  28  upon which bucket  20  rotates. The purpose of bucket bracket  24  is to provide a hinge for pivotally mounting arm  30  of movable thumb  22 . In one embodiment, bucket bracket  24  may comprise two rectangular elements welded to one side of bucket  20  as shown in  FIG. 3 . Holes  25  may be utilized for insertion of hinge pin  26 . 
     Bucket bracket  24  may be welded to backhoe bucket  20 . In another possible embodiment, bucket bracket  24  may be removable and comprise an arm which is inserted into a socket and pinned into position so as to be removable if desired. As noted above, bucket bracket  24  provides a hinge or pivot for arm  30  of movable thumb  22 . In this case, the hinge may utilize removable pin  26  to permit removal of movable thumb  22 . The hinge or pin  26  may be provided closer to or further away from the edge of the open end of bucket  20 , as desired. 
     In this embodiment, bucket bracket  24  is positioned near the side of the bucket closest to the backhoe arm which avoids interference with operation of bucket  20  during digging or the like. Bucket bracket  24  may also extend away from the open side of bucket  20 . However, hinge  26  provided by bucket bracket  24  could also be located somewhat within the interior of bucket  20  but is then preferably near the bucket hinge  28 . 
     At least one link member  32  is pivotally or pin mounted to backhoe stick  14  on one end or end portion, and is also pin mounted to arm  30  of movable thumb  22  on the opposite end or end portion. Holes  35  and  37 , as shown in  FIG. 5A  and  FIG. 5B , may be utilized for respective pin members  34  and  36 . 
     Pins  26 ,  34 , and  36  may be removable pins. The pins may have holes in one end, which are held or latched in place by Cotter pins or other clips, pins, latches, or the like, which prevent pins  26 ,  34 , and  36  from unintentional removal. Because pins  26 ,  34 , and  36  are removable, link member  32  and movable thumb  22  are readily removable from bucket  20 . 
       FIG. 5A  and  FIG. 5B  show different embodiments of a link member, which connects between is stick boom  14  and arm  30  of movable thumb  22 . If desired, length adjust segments, such as length adjust segment  42 , may be added to or removed from link member  32  to vary the closure distance between movable thumb  22  and bucket  20 . For example, it may be desired to have an offset of a few inches between the rim of bucket  20  and movable thumb  22  when these components are rotated to the closed position. Alternatively, it may be desired that movable thumb  22  engage or almost engage bucket  20 . 
     Movable thumb  22  may be referred to herein as a movable closure element, movable lid, hinged flap, or the like. Movable thumb  22  may take various shapes as desired. 
     It will be appreciated that the pins, fasteners, and the like for the elements of bucket bracket  24 , movable thumb  22 , in link members  32  discussed above may be provided in various ways, positions, and arrangements. For example, there are many ways that link members  32  may be pivotally attached to backhoe stick  14 . Pins could be welded to backhoe stick  14  for connection to link members  32 . A single pin may connect both laying members  32  to backhoe stick  14 . Alternatively, a bracket (not shown) may be mounted to backhoe stick  14  and utilized to pivotally connect to link members  32 . 
     Link member(s)  32  may be relatively straight as shown but could also be bent, curved, angled, or the like as needed, desired, are most convenient for proper opening and closing movable thumb  22  with respect to bucket  20 . 
     It will be appreciated that the length of link members  32 , and position of hinges  26  and  34  on movable thumb  22 , as well as the position and length of bucket bracket  24  will determine the opening and closing positions of movable thumb  22  with respect to bucket  20 . As discussed above, an offset between movable thumb  22  and bucket  20  in a closed position can be adjustable utilizing adjustment sections, if desired. 
       FIG. 4  shows one possible embodiment for movable thumb  22 . Many possible variations may be utilized. For example, movable thumb  22  may comprise a flap hinged to bucket  20 , which may completely or almost completely covers the opening of bucket  20 . In one embodiment, bucket bracket  24  may be positioned on the sides of bucket  20  to provide a hinge for the flap. In this embodiment, link member  32  is modified accordingly to pivotally engage and pivotally connect to a wider flap. Movable thumb  22  might also comprise a screen or the like. In any case, it will be understood that movable thumb  22  may be of various shapes and designs. However, in accord with the present invention, bucket  20  and a movable thumb  22  moves in concert with each other for opening and closing. 
     Referring to  FIG. 1 , during operation, if bucket  20  is rotated clockwise as controlled by hydraulic cylinder  18 , then movable thumb  22  rotates counterclockwise relative to bucket  20 . This is because link member  32  pulls movable thumb in this direction in response to clockwise rotation of bucket  20 . Movable thumb  22  is constrained to rotate around pivot  26 . 
     Referring to  FIG. 2 , if bucket  20  is rotated counterclockwise by hydraulic cylinder  18 , then movable thumb  22  is rotated clockwise. Because one hydraulic cylinder controls rotational movement of both bucket  20  and movable thumb  22 , it is very easy for an operator to control both of these functions quickly and conveniently as compared to the prior art hydraulic movable thumb. 
     The invention does not require another control lever to operate the movable thumb assembly nor does it require operation of three levels almost at the same time to push the dirt or object in order to perform the task. In this way, the results of the job can be performed better and faster. By utilizing only one hydraulic control lever to operate bucket  20  and movable thumb assembly  10 , the operator has more precise control, gets the job completed faster, more simply, and provide easier and more accurate placement of material. Also, the gap between the thumb and the bucket is greater when in the open position to allow handling of bigger objects. 
     Many additional changes in the details, components, steps, and organization of the system, herein described and illustrated to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention. It is therefore understood that within the scope of the appended claims, the invention may be practiced otherwise pulls as specifically described.