Abstract:
In the operation of a work machine of the type having an attachment having more than one implement, it is oftentimes desirable or necessary to operate one implement to the exclusion of the other requiring the operator to manually chain, bolt, or otherwise secure the non-used implement to the work machine. The present invention provides a locking device for use with a work machine which includes a base portion for attachment to the work machine, an engagement member rotatably coupled to the base portion, a receiving portion attached to the engagement portion and a latching mechanism constructed and arranged to maintain the engagement member in a fixed position, relative to the base portion, when the latching mechanism is in a latched position

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to a work tool locking device and, more specifically, to a work tool locking device for releasably maintaining a work tool against the body of a work machine when not in use.  
         BACKGROUND  
         [0002]    Work machines may typically have operable work tools or attachments such as buckets, grapples or the like connected therewith. Oftentimes, an attachment may consist of two implements such as, for example, a bucket and thumb each of which may be individually operated to effectuate the desired operation. Oftentimes, it is desirable or necessary to operate one implement to the exclusion of the other. This may arise, for example, in trenching operations in which it is desirable to use the bucket without the thumb. In order to prevent inadvertent movement of the non-used implement which may interfere with the operations being performed, it is oftentimes necessary for the operator to exit the operator station and chain, bolt, or otherwise secure the non-used implement to the work machine.  
           [0003]    The subject invention is directed at overcoming one or more of the problems as set forth above.  
         SUMMARY OF THE INVENTION  
         [0004]    In one aspect of the present invention, a locking device for use with a work machine having an implement is provided. The locking device includes a base portion for attachment to the work machine, an engagement member rotatably coupled with the base portion, a receiving portion attached to the engagement portion, and a latching mechanism constructed and arranged to maintain the engagement member in a fixed position, relative to the base portion.  
           [0005]    In another aspect of the present invention a method of remotely preventing inadvertent rotation of an implement relative to a work machine, the implement being movable by a hydraulic cylinder, is provided. The method comprises the steps of: providing the work machine with a locking device including an engagement member rotatably coupled to the work machine, a receiving portion attached to the engagement portion, and a latching mechanism constructed and arranged to maintain the engagement member in a fixed position, relative to the work machine, when the latching mechanism is an a latched position. The method also provides for the step of providing the work machine with a catch member, actuating the hydraulic cylinder in such a manner as to cause the catch member to engage the receiving portion, and continuing to actuate the cylinder thereby causing the engagement member to rotate in a first direction until the latching mechanism is in a latched position. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a diagrammatic side elevation view of a work machine embodying the principals of the present invention.  
         [0007]    [0007]FIG. 2 is a diagrammatic side elevation view showing one implement in a latched position.  
         [0008]    [0008]FIG. 3 is a diagrammatic view of a locking device of the present invention.  
         [0009]    [0009]FIG. 4 is diagrammatic cross-sectional view, taken through section  3 - 3  in FIG. 3, of the locking device of FIG. 3. 
     
    
     DETAILED DESCRIPTION  
       [0010]    With reference now to the Figures, shown in FIGS. 1 and 2 is a portion of a work machine  100  of the type having a stick  101  on which is pivotally mounted an attachment  104 . The attachment  104 , in turn, comprises a first implement part  105  which is pivotable, relative to the stick  101 , about pin  108 . Also shown is a second implement part  109  which may also be pivotable, relative to the stick  101 , about pin  108 . For purposes of illustration and not limitation the first and second implement parts  105 , 109  will be illustrated and described herein as, respectively, a thumb and a bucket. However, such a showing is exemplary only and it is contemplated that other types of implements may also be used without deviating from the spirit of the present invention. A first motor, preferably a hydraulic cylinder  113 , is coupled at its end  114  to the first implement part  105  by use of a linkage assembly  117  and is actuatable to position the first implement part  105  relative to the stick  101 . In addition, a second motor, also preferably a hydraulic cylinder  118 , is coupled to the second implement part  109  and is actuable to position the second implement part  109  relative to the stick  101 .  
         [0011]    Linkage assembly  117  comprises a first linkage  121  extending between, and thereby coupling, the stick  101  and the first hydraulic cylinder  113 , and a second linkage  122  which couples the first hydraulic cylinder  113  to the first implement part  105 . A catch member  125  is attached, preferably integrally, to an end  126  of the first linkage  121  and is used to engage a locking device  129  which is attached to the body  130  of the work machine  100 , preferably the stick  101 . However, it is to be understood that such a showing is exemplary only and other attachment locations are contemplated such as, for example, on the attachment  104  or linkage assembly  117 . Although the details of the locking device  129  will be described more fully as this disclosure progresses, suffice to say for now, the locking device  129  advantageously maintains the first implement part  105  in a stationary position when it is desirable to only use the second implement part  109 , and the first implement part  105  would otherwise interfere with efficient use of the second implement part  109  if not held in place. It is to be understood that the attachment of the catch member  125  to the first linkage  121  is exemplary only and that other attachment locations for the catch member  125  may be used such as, for example, the first hydraulic cylinder  113  or the first implement part  105 .  
         [0012]    With reference to FIGS. 3 and 4, the details of the locking device  129  will now be discussed. The locking device  129  includes a base portion  300  having preferably four openings  301  for receiving fasteners (not shown) which are used to couple the base portion  300  to either the stick  101  or to a separate boss (not shown) which may be integrally attached to the stick  101 . A retaining member  304  is coupled to the base portion  300  preferably by use of fasteners  305 . An engagement member  308  is rotatably coupled with the base portion  300  and includes a receiving portion  309  for receiving the catch member  125 . Also shown are grease fittings  310  which are used facilitate lubrication of the locking device  129 .  
         [0013]    With reference to the FIG. 4 cross-sectional view, the retaining member  304  is spaced apart from the base portion  300  by use of a spacer  400  which is concentrically placed within an opening  401  provided in the engagement member  308 . Biasing members  404 , preferably comprising springs, are placed between the engagement member  308  and the retaining member  304  and are used to bias or urge the engagement member  308  towards the base portion  300 . Although the aforementioned use of the springs for the biasing members  404  are the preferred means to urge the engagement member  308  towards to the base portion  300 , it is also contemplated that other means may be used as well such as placing an elastomeric member or members between the retaining member  304  and the base portion  300 . As used herein, “elastomeric member” refers to those materials that are able to compress and then substantially expand to their pre-compressed shape.  
         [0014]    The locking device  129  further includes a latching mechanism which is shown generally at  405 . The latching mechanism  405  comprises a plurality of bodies  406  (one shown), preferably comprising ball bearings, each placed within a corresponding pocket  408  formed in the base portion  300 . The bodies  406 , in turn, engage a corresponding indentation  409  (one shown) provided in the engagement member  308  when the locking device  129  is in a latched position. As used herein, “latched position” refers to that configuration of the locking device  129  in which the indentations  409  engage the bodies  406 . The engagement member  308  may be provided with a groove  410  which operates as a guide for the bodies  406  so as to maintain the engagement member  308  in a fixed, centered position. Also as shown, the grease fittings  310  are in communication with the pockets  408  and are used to channel an external source of lubrication to the ball bearings or bodies  406 .  
         [0015]    Although not shown, other alternative arrangements for the latching mechanism  405  may also be used such as, for example, instead of using a separate body  406 , providing a fixed protrusion (not shown) on the engagement member  308  to engage the pocket  408  on the base portion  300 , or providing the fixed protrusion on the base portion  300  to engage the indentation  409  on the engagement members  308   
       INDUSTRIAL APPLICABILITY  
       [0016]    In use and in operation, the locking device  129  of the present invention allows one implement part of at least a two implement attachment to be stowed-away while the other implement part is being used. With reference to the Figures, actuation of the first hydraulic cylinder  113  in such a manner as to cause the first implement part  105  to rotate in a first or counter-clockwise direction (e.g., away from the second implement part  109 ) causes the catch member  125  to engage the receiving portion  309 . Continued actuation of the first hydraulic cylinder  113  causes the engagement member  308  to rotate, relative to the base portion  300 , until the indentations  409  provided on the engagement member  308  engage the ball bearings or bodies  406 , at which point the locking device  129  is in a latched position. As should be appreciated by those of ordinary skill in such art, when in the aforementioned latched position, the first implement part  105  is prevented from “drifting” or otherwise moving from the latched position while the second implement part  109  is being used without the need for the operator to exit the operator station and manually secure the first implement part  105  to the stick  101 .  
         [0017]    Releasing the first implement part  105  from the locking device  129  consists of simply actuating the first hydraulic cylinder  113  in such a manner as to cause the first implement part  105  to rotate in a second or clockwise direction (e.g., towards the second implement part  109 ). When sufficient hydraulic pressure has accumulated in the first hydraulic cylinder  113 , the engagement member  308  is forced to rotate against the force of the biasing members  404  thereby disengaging the indentations  409  from the bodies  406  and releasing the first implement part  105 . Each of the biasing members  404  may be suitably selected from one of ordinary skill in such art such that the locking device  129  can only be placed in the unlatched state when a sufficient amount of hydraulic pressure has accumulated in the first hydraulic cylinder  113 . As used herein “unlatched position” refers to that position in which the indentations  409  are disengaged from the bodies  406 . In addition, a switch-type mechanism (not shown) is also contemplated to unlatch the locking device  129 . The switch-type mechanism may comprise a mechanical, electrical, hydro-electrical, electromechanical or other type of switch which may be actuated from the operator&#39;s station and coupled to the locking device  129  in a manner readily apparent to those of ordinary skill in such art.  
         [0018]    Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.