Abstract:
A control apparatus for a bucket loader allows a single linear actuator to provide multiple operative functions for the bucket loader. A selector link is pivotally mounted on the back plate of loader bucket to selectively connect the back plate to the base portion of the linear actuator so that the extendable portion powers a pivoting of the bucket shell to dump material from the bucket, or connect the back plate to the extendable portion of the linear actuator to power the vertical movement of the back plate. A chain interconnects the extendable portion of the linear actuator and the pivotable bucket shell to power the pivoting of the bucket shell when the selector link is connected to the base portion. The bucket shell can be mechanically locked into an open position to allow the back plate to be utilized as a push blade.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims domestic priority on U.S. Provisional Patent Application Ser. No. 60/970,063, filed on Sep. 5, 2007, the contents of which are incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates generally to bucket loaders that are optionally mounted on small tractors to provide a material handling capability, and more particularly, to a bucket loader that is operable to perform multiple functions utilizing a single actuator. 
   BACKGROUND OF THE INVENTION 
   Bucket loaders are an optional attachment that can be mounted on tractors to provide material handling capability. The bucket loader typically has a frame that is detachably supported on the tractor, a pair of forwardly extending boom arms pivotally mounted on the frame, and a bucket pivotally supported on the forward ends of the boom arms to engage material forwardly of the tractor. The bucket is typically pivotable to scoop material, moving the front edge of the bucket up and down, while the pivotally movable boom arms are operable to raise and lower the bucket. 
   The tractor providing motive and operational power for the bucket loader can be substantially any size from the large farm tractors to the small garden tractors that are often used to mow lawns in a residential setting. Large tractors have onboard hydraulic systems that are used to power hydraulic cylinders mounted on the bucket loader to cause pivotal movement of the components thereof. The smaller garden tractors do not typically carry onboard hydraulic systems, requiring any actuators powering the pivotally movable components of the bucket loader to be electrical, rather than hydraulic. All terrain vehicles (ATV), sometimes referred to as four-wheelers, can also have small bucket loaders mounted on them to increase the versatility and flexibility of operation thereof. Each operable function of the bucket loader conventionally requires a separate actuator. The boom lift function, particularly on large tractors, is powered by a pair of hydraulic cylinders, one positioned on each boom arm. The pivotal movement of the bucket relative to the boom arms is normally powered by a separate actuator. 
   Bucket loaders for small garden tractors and ATV&#39;s are usually constructed somewhat differently than the bucket loaders for large tractors. First, the overall size of the bucket loader apparatus is substantially smaller, as the bucket, boom arms and frame are sized to be adapted to the smaller garden tractor configuration. Since the bucket is relatively small and has a relatively small load capacity, the tilt function for the bucket can be operated and powered manually, reserving the actuator power for lifting the boom arms and the attached bucket. The pivotal range of such buckets, however, is limited, often resulting in the retention of some of the material loaded into the bucket when the bucket is tipped to empty the material from the bucket. 
   Split bucket configurations, often referred to as clamshell buckets, are known for larger bucket loader configurations, but are not particularly adaptable to the small bucket loaders because of the need to power the operation of the pivoted forward shell portion of the bucket relative to the rearward back plate portion on which the shell portion is pivotally mounted. The clamshell bucket has the extra advantage of being capable of opening the forward shell portion of the bucket to expose the back plate portion and enable the back plate portion to be operated as a blade to push material around, rather than lift the material in the bucket function. 
   It would be desirable to provide a bucket loader that would provide a clamshell bucket configuration for use on a small tractor or other vehicle. It would also be desirable to provide a linkage mechanism that would enable a single actuator to perform multiple functions on the bucket loader, particularly the functions of lifting the bucket and operating the clamshell bucket apparatus. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to overcome the disadvantages of the prior art by providing a bucket loader for a small tractor in which multiple operative functions of the bucket are controlled through a single linear actuator. 
   It is another object of this invention to provide a control mechanism to cooperate with a single linear actuator to control multiple operative functions of a bucket loader. 
   It is a feature of this invention that the linear actuator is connected to a lift linkage that is cooperable with a selector link to control the effect of the extension of the linear actuator. 
   It is an advantage of this invention that the single linear actuator can control the operation of the bucket between digging and dumping functions. 
   It is another feature of this invention that the selector link is coupled to the extendable ram of the linear actuator to move the bucket up and down. 
   It is still another feature of this invention that the selector link is coupled to the base portion of the linear actuator to secure the back plate of the bucket with the base portion of the linear actuator so that the extension of the movable ram will affect a pivotal movement of the bucket shell relative to the back plate. 
   It is another advantage of this invention that the extendable portion of the linear actuator is connected to the bucket shell by a flexible member, such as a chain, to affect movement of the bucket shell when the back plate is secured to the base portion of the linear actuator. 
   It is still another advantage of this invention that the bucket shell is pivotally mounted to the back plate of the loader bucket to permit movement of the bucket shell relative to the back plate to allow material positioned within the loader bucket to be dumped therefrom. 
   It is yet another feature of this invention that the bucket shell can be locked into an open position to allow the back plate to be utilized as a blade member to push material. 
   It is still another feature of this invention that the selector link connected to the extendable portion of the linear actuator will function to move the back plate vertically in response to movement of the extendable portion of the linear actuator while the bucket shell is locked into an open position. 
   It is yet another advantage of this invention that the movement of the selector link is controlled by an actuator handle that is positioned for manipulation by the operator seated on the seat of the small tractor. 
   It is still another advantage of this invention that the linear actuator can be powered electrically. 
   It is still another object of this invention to provide a bucket loader for a small tractor which is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
   These and other objects, features and advantages are accomplished according to the instant invention by providing a control apparatus for a bucket loader that allows a single linear actuator to provide multiple operative functions for the bucket loader. A selector link is pivotally mounted on the back plate of loader bucket to selectively connect the back plate to the base portion of the linear actuator so that the extendable portion powers a pivoting of the bucket shell to dump material from the bucket, or connect the back plate to the extendable portion of the linear actuator to power the vertical movement of the back plate. A chain interconnects the extendable portion of the linear actuator and the pivotable bucket shell to power the pivoting of the bucket shell when the selector link is connected to the base portion. The bucket shell can be mechanically locked into an open position to allow the back plate to be utilized as a push blade. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The advantages of this invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
       FIG. 1  is a left side elevational view of a bucket loader incorporating the principles of the instant invention mounted on a small garden tractor, the bucket being shown in the lowered material engaging position; 
       FIG. 2  is an upper right front perspective view of the bucket loader shown in  FIG. 1 ; 
       FIG. 3  is an upper front left perspective view of the bucket loader shown in  FIG. 1 ; 
       FIG. 4  is a right rear perspective view of the bucket loader shown in  FIG. 1  with the actuator handle being broken away for purposes of clarity; 
       FIG. 5  is a top plan view of the bucket loader shown in  FIG. 4 ; 
       FIG. 6  is a cross-sectional view of the bucket loader taken along lines  6 - 6  in  FIG. 5  to show an elevational view of the selector link, the linear actuator and the lift mechanism, the loader bucket being in a lowered material engaging position; 
       FIG. 7  is a cross-sectional view of the bucket loader similar to that of  FIG. 6 , but showing the loader bucket ins a raised position as though to elevate material gathered into the loader bucket; 
       FIG. 8  is a cross-sectional view of the bucket loader similar to that of  FIG. 7  but showing the movement of the selector link in phantom to change the operative effect of the linear actuator; 
       FIG. 9  is a cross-sectional view of the bucket loader similar to that of  FIG. 6 , but showing the operative function of pivoting the bucket shell to dump the material collected in the loader bucket by virtue of moving the selector link into engagement with the base portion of the linear actuator; 
       FIG. 10  is a cross-sectional view of the bucket loader similar to that of  FIG. 9 , but showing the movement of the lock member in phantom to secure the bucket shell in an open position, and the movement of the selector link in phantom to reconnect the back plate to the extendable portion of the linear actuator; 
       FIG. 11  is a cross-sectional view of the bucket loader similar to that of  FIG. 10 , but showing the operation of the back plate as a push blade; 
       FIG. 12  is a upper left front perspective view of the bucket loader in the push blade configuration shown in  FIG. 11 , the actuator handle being broken away for purposes of clarity; 
       FIG. 13  is a side elevational view of the bucket loader with the bucket being down in a loading position next to the ground; 
       FIG. 14  is a side elevational view of the bucket loader shown in  FIG. 13  with the bucket being raised off the ground; 
       FIG. 15  is a side elevational view of the bucket loader shown in  FIG. 14  with the movement of the selector link being shown in phantom; 
       FIG. 16  is a side elevational view of the bucket loader shown in  FIG. 15  with the shell portion of the clam shell bucket being opened while the boom arms are fully raised to affect a dumping of any material gathered in the loader bucket; and 
       FIG. 17  is a side elevational view of the bucket loader shown in  FIG. 16  with the clamshell bucket being locked in the fully opened position and the back plate being used as a push blade. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, the structural components of the bucket loader apparatus  10  can best be seen. Any left and right references are used as a matter of convenience and are determined by standing at the rear of the garden tractor T and facing the forward direction, the normal direction of travel, with the bucket loader being mounted at the forward end of the garden tractor T. One skilled in the art will understand that the principles of the instant invention are not limited to a bucket loader apparatus  10  that is mounted on a small garden tractor T, and could be applied to a bucket loader that is supported on a much larger tractor or other prime mover (not shown), such as an all terrain vehicle (ATV). Since the preferred embodiment is a bucket loader apparatus  10  that is mounted on a small garden tractor T, this is the embodiment shown in the drawings. 
   The bucket loader apparatus  10  includes a mounting frame  12  that is connected to the frame F of the garden tractor T, which is typically provided with mounting brackets B for the purpose of mounting attachments, such as blades, snow blowers, mowers, etc. Thus, the mounting frame  12  is fixed relative to the tractor T and provides a base from which the remaining components of the bucket loader apparatus  10  can operate. A lift mechanism  15  is pivotally supported on the mounting frame  12  at pivot  14  and includes a centrally located lift arm  16  and a pair of laterally spaced boom arms  17  that are connected to the bucket  20 . A transverse connecting link  18  interconnects the laterally spaced boom arms  17  to provide a pivot axis for the central lift arm  16 . 
   The bucket  20  is formed as a clamshell bucket that has a back plate  22  carrying a support bracket  21  to which the lift mechanism  15  is connected. A bucket shell  25  is pivotally mounted on the back plate  22  by a rock shaft  24  such that the bucket shell  25  is pivotally movable between a lowered bucket-forming position next to the back plate  22 , as is shown in  FIGS. 1-8 , and a raised blade-forming position, as is depicted in  FIGS. 9-12 . The pivotal movement of the bucket shell  25  is affected through a chain  27  connected to the bucket shell  25  at a central location thereon, wrapping around a guide bracket  28  fixed on the rock shaft  24  and extending downwardly therefrom for connection to the lift mechanism  15  for operation as will be described in greater detail below. The central lift arm  16  extends forwardly into engagement with the support bracket  21 , but located below the support bracket  21  such that the central lift arm  16  is operable to lift vertically the support bracket  21  and the attached back plate  22 . As is best seen in  FIGS. 3-5  and  12 , the back plate  22  carries a lock member  23  at a transverse end thereof to be selectively engagable with a connector  26  carried by the bucket shell  25  to restrain the bucket shell  25  in the raised blade forming position. 
   The mounting frame  12  supports an actuator  30  that is oriented generally vertically at a forward central location on the mounting frame  12 . The actuator  30  can be hydraulically or electrically operated, though for small tractors, such as the garden tractor T, the actuator  30  is preferably electrically operated so as to be connected to the electrical system of the tractor T. Preferably, the actuator  30  is associated with a housing  32  that is physically connected to the mounting frame  12  with the housing  32  supporting the actuator  30  which includes a body portion mounted in the housing  32  and an extendable piston  35  that preferably extends downwardly from the body portion. The housing  32  carries an upper pin  33  connecting the body portion of the actuator  30  to the housing  32  and a lower pin  34  connecting the distal end of the piston  35  to the central lift arm  16  of the lift mechanism  15 . Thus, the lift mechanism  15  moves vertically in conjunction with the extension and contraction of the piston  35  relative to the body portion of the actuator  30 . 
   The bucket loader apparatus  10  further includes a selector linkage  40  that is manually operable by the operator (not shown) seated on the tractor T. The selector link  42  is affixed to a pivot shaft  41  so as to be pivotally movable therewith. The pivot shaft  41  also has manipulator arm  45  connected thereto to cause pivotal rotation of the pivot shaft  41 . The manipulator arm  45  is connected to an actuation link  46  that extends rearwardly therefrom for access by the operator seated on the tractor T. When the operator pulls the actuator link  46  rearwardly, the manipulator arm  45  rotates the pivot shaft  41  so that the top portion of the selector link  42  moves rearwardly, while the bottom portion of the selector link  42  moves forwardly. A tension spring  49 , shown in  FIG. 5 , is anchored on the adjacent boom arm  17  and is connected to an extension of the manipulator arm  45  positioned below the pivot shaft  41  to bias the manipulator arm  45 , and the associated selector link  42 , such that the top portion of the selector link  42  is urged forwardly. As a result, the selector link  42  is biased such that the lower retainer hook  44  is in engagement with the lower pin  34 . 
   The selector link  42  is formed with an upper retainer hook  43  on the top portion of the selector link  42  and with a lower retainer hook  44  on the bottom portion of the selector link  42 . The upper retainer hook  43  of the selector link  42  is engagable with the upper pin  33  when the top portion of the selector link  42  is pivoted rearwardly, while the lower retainer hook  44  is engagable with the lower pin  34  when the top portion of the selector link  42  is pivoted forwardly. In operation, the engagement between the lower retainer hook  44  and the lower mounting pin  34  operatively couples the central lift arm  16  to the supporting bracket  21 , and thus to the back plate  22 , to cause vertical movement of the back plate  22 . Alternatively, the engagement between the upper retainer hook  43  and the upper pin  33  fixes the back plate  22  to the housing  32  and the mounting frame  12  on which the housing  32  is affixed, leaving the central lift arm  16  to move downwardly relative to the back plate  22  away from the support bracket  21 . 
   The normal operation of the bucket loader  10  to load into and unload material from the bucket  20  can best seen in  FIGS. 6-17 . Referring first to  FIGS. 6 and 13 , the selector link  42  is pivoted so that the lower retainer hook  44  is engaged with the lower pin  34  to operatively couple the lift mechanism  15  to the bucket  20 . The piston  35  is extended from the body portion of the actuator  30  to drive the bucket  20  onto the surface of the ground. In fact, the actuator  30  can place substantial down pressure on the bucket  20  to force the bucket  20  onto the ground. The tractor is then driven into the material to be loaded (not shown) so that the bucket  20 , with the bucket shell  25  placed into the lowered bucket-forming position, is filled with the material. 
   As is reflected in  FIGS. 7 and 14 , the piston  35  is retracted into the body portion of the actuator  30  so that the central lift arm  16  lifts the support bracket  21 , drawing the boom arms  17  and the attached bucket  20  upwardly. Once the piston  35  is fully, or substantially fully, retracted, the manipulator arm  45  is pulled rearwardly pivoting the selector link  42 , as depicted in  FIGS. 8 and 15 , so that the upper retainer hook  43  becomes engaged with the upper pin  33 . The lifting of the support bracket  21  by the central lift arm  16  takes the pressure off of the selector link  42  so that the manipulator arm  45  is able to cause a pivotal movement of the selector link  42 . With the back plate  22  secured to the housing  32  by the engagement of the upper retainer hook  43  with the upper pin  33 , the subsequent downward movement of the piston  35  lowers the central lift arm  16  with the chain  27  connected thereto, affecting a corresponding upward pivotal movement of the bucket shell  25  from the lowered bucket-forming position. The separation of the bucket shell  25  from the back plate  22  with the back plate raised into an elevated position, secured by the selector link  42 , effectively causes the material to be dumped from the bucket  20 , as is represented in  FIGS. 9 and 16 . 
   A recycling of the piston  35  back into the body portion of the actuator  30  allows the bucket shell  25 , powered by gravity, but operatively controlled by the upwardly moving chain  27  connected to the central lift arm  16 , to return to the bucket-forming position adjacent the back plate  22 . Once the piston  35  has been retracted into the body portion of the actuator  30 , the selector link  42  can be pivoted forwardly, urged by the biasing tension spring  49 , to allow the subsequently extending piston  35  to lower the bucket  20  back to the ground with the bucket shell  25  lowered against the back plate  22 . Accordingly, the actuator  30  is used to perform two independent tasks as determined by the positioning of the selector link  42 . Thus, the bucket  20  can be used to scoop loose material and make an effective emptying of the bucket  20  by separating the bucket shell  25  from the back plate  22  through a recycling of the actuator  30 . 
   When the bucket  20  has been lifted and the actuator  30  has been recycled to open the bucket shell  25 , as described above, the lock member  23  can be pivoted on the back plate  22  to engage the connector  26  on the side of the bucket shell  25  to lock the bucket shell  25  in the raised position, as is represented in  FIGS. 10 and 16 . In this orientation, the piston  35  of the actuator  30  is extended to draw the chain  27  downwardly to open the bucket shell  25 . A subsequent retraction of the piston  35  into the body portion of the actuator  30  accomplishes nothing but allowing the selector link  42  to be pivoted so that the subsequent extension of the piston  35  will lower the bucket  20  back to the ground. Since, however, the bucket shell  25  is locked in the opened position by the lock member  23 , the bucket  20  is lowered with the back plate  22  exposed as a blade so that the back plate  22  can be utilized to push material around without scooping the material into the bucket  20 , as is shown in  FIGS. 11 ,  12  and  17 . 
   To return the bucket  20  to a bucket configuration, instead of the blade configuration, the piston  35  is again retracted into the body portion of the actuator  30  to raise the bucket  20  until the selector link  42  can be pivoted so that the top retainer hook  43  engaged with the upper pin  33 . The subsequent extension of the piston  35  from the actuator  30  extends the chain  27  to take the weight off the lock member  23  and allow the lock member to be released from the connector  26 . A subsequent retraction of the piston  35  allows the bucket shell  25  to return to the lowered position against the back plate  22 . Then, a pivoting of the selector link  42  to engage the lower retainer hook  44  with the lower pin  34  allows the extension of the piston  35  to lower the bucket  20  to the ground in the bucket configuration. 
   It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.