Patent Publication Number: US-6663338-B1

Title: Three-point hitch loader

Description:
FIELD OF THE INVENTION 
     The present invention relates to tractor-mounted loaders and, more particularly, to a loader that is adapted to mount to the three-point hitch of a tractor. 
     BACKGROUND OF THE INVENTION 
     Front end loaders are widely used today. Basically, a front end loader is mounted to a tractor such that the bucket is supported in front of the tractor by a pair of lift arms that extend forwardly along opposite sides of the tractor. Generally, front end loaders require two sets of hydraulic remotes. A first hydraulic remote is operative to articulate the front bucket while the second set of hydraulic remotes is utilized to raise and lower the lift arms. 
     Many front end loaders are designed to handle fairly heavy-duty loading operations. Front end loaders are used in a wide variety of areas. For example, they are extensively used in the construction industry, in farming operations, in landscaping, and in a host of other areas. However, front end loaders are generally dedicated to a tractor. That is, it is not very easy to connect and disconnect a front end loader from a tractor. Therefore, one will find that, as a general rule, front end loaders remain mounted to a tractor for relatively long periods of time. This, of course, means that the tractor is tied up and not useful with other implements. In addition, the front end loader mounted on a tractor tends to cause wear and tear on the front end of a tractor because of the load placed on the front end of the tractor by the front end loader itself. 
     Therefore, there has been, and continues to be, a need for a loader that can be quickly and easily mounted to a tractor, especially a tractor in the 25-60 hp range. Further, there is a need for a tractor-mounted loader that will only require one set of hydraulic remotes. 
     SUMMARY OF THE INVENTION 
     The present invention entails a loader adapted to be mounted to the three-point hitch of a tractor. The loader, in a preferred embodiment, includes a hitch frame that is attachable to the three-point hitch of the tractor. Extending from the hitch frame is a lift arm structure that is movably mounted to the hitch frame. Mounted to the lift arm structure is a bucket that is controlled by a bucket actuator. A flexible line or cable is connected to the lift arm structure and at least one portion of the cable is fixed or secured at a point relative to the three-point hitch of the tractor. Thus, when the three-point hitch of the tractor is raised or lowered, the cable will cause the lift arm structure to raise or lower in response to the movement of the three-point hitch. 
     In one embodiment of the present invention, the bucket is adapted to assume two modes, a loader mode and a box blade mode. In the loader mode, the bucket performs conventional loading tasks. In the box blade mode, the bucket is rotated such that it assumes a conventional box blade position. 
     Further, in another embodiment, the loader of the present invention can be adapted to function as a forklift. In this case, a pair forks are secured to the bucket. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of the rear end loader of the present invention. 
     FIG. 2 is a side elevational view of the rear end loader of the present invention showing the lift arm structure in a raised position and further showing the bucket being disposed in a number of positions. 
     FIG. 3 is a top plan view of the rear end loader of the present invention. 
     FIG. 4 is a sectional view taken through the line  4 — 4  of FIG.  1 . 
     FIG. 5 is a side elevational view of the rear end floater where the bucket assumes a box blade mode. 
     FIG. 6 is a side sectional view showing the area encircled in FIG.  5 . 
     FIG. 7 is a perspective view of the bucket adapted to function as a forklift. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With further reference to the drawings, particularly FIGS. 1 and 2, the rear end loader of the present invention is shown therein and indicated generally by the numeral  10 . Rear end loader  10  is adapted to mount to a tractor indicated generally by the numeral  12 . The tractor  12  includes a conventional three-point hitch. The three-point hitch of the tractor  12  includes a pair of laterally-spaced lower draft links  16  and an upper link  18 . As seen in FIGS. 1-3, the threepoint hitch extends rearwardly from the tractor  12  and between the rear wheels  14  of the tractor. As will be appreciated from subsequent portions of this disclosure, the rear end loader  10  is adapted to be connected and disconnected from the three-point hitch of the tractor  12 . 
     Viewing the basic components or subassemblies of the loader  10 , it is seen that the loader includes a hitch frame indicated generally by the numeral  20 . Hitch frame  20  is adapted to be connected to the three-point hitch of the tractor  12 . Extending rearwardly from the hitch frame  20  is a lift arm structure indicated generally by the numeral  22 . Lift arm structure  22  is pivotally mounted to the hitch frame  20  and can be raised and lowered with respect to the hitch frame  20 . Secured to the rear end portion of the lift arm structure  22  is a bucket indicated generally by the numeral  24 . The bucket  24  is pivotally mounted to the lift frame structure  22  and can be articulate and moved clockwise or counterclockwise, as viewed in FIG. 2, by a bucket actuator indicated generally by the numeral  26 . As will be appreciated from subsequent portions of this disclosure, the bucket actuator  26  comprises a hydraulic cylinder that is interconnected between the lift arm structure  22  and the bucket  24 . To raise and lower the lift frame structure  22  with respect to the hitch frame  20 , there is provided a flexible line or cable  28  that is connected between the lift arm structure  22  and a draw bar  19  that is associated with the tractor  12 . Flexible line  28  functions to lift the lift arm structure  22  in response to the three-point hitch of the tractor being raised. Further flexible line  28  functions to lower the lift arm structure in response to the three-point hitch of the tractor  12  being lowered. 
     Turning to the hitch frame  20 , as noted above, the hitch frame is adapted to be connected directly to the three-point hitch of the tractor  12 . Hitch frame  20  includes a vertical post member indicated generally by the numeral  50 . Vertical post member  50  includes a generally rectangular upper frame  66  and a pair of legs  52  that extend downwardly from the rectangular frame  66  and at the same time diverge outwardly. Extending between the lower portions of the legs  52  as a transverse connecting bar  68 . Reinforcing the hitch frame is a pair of gussets  54  that extend upwardly from the legs  52  and join the side of the rectangular frame  66 . 
     As seen in the drawings, particularly FIG. 3, hitch frame  20  is connected at three points to the three-point hitch of the tractor  12 . About the lower portion of the hitch frame  20 , on opposite sides thereof, there is provided a connecting plate that includes an outward extending pin  56  that is operative to connect with one of the lower draft links  16  of the three-point hitch. The third connecting point is formed by a pair of spaced-apart upper connecting plates  58  that project rearwardly from the vertical post member  50  of the hitch frame  20 . There is provided an upper connecting pin  60  that extends through openings within the plates  58  and which acts to connect the upper link  18  of the three-point hitch to the hitch frame  20 . 
     Mounted within the hitch frame is a pair of pulleys, an upper pulley  62  and a lower pulley  64 . As will be appreciated from subsequent portions of the disclosure, the flexible line of  28  is trained around pulley  62  and  64  as the flexible line extends forwardly from the lift arm structure  22  to the draw bar  19  of the tractor. 
     Extending rearwardly from the hitch frame  20  is the lift arm structure  22 . Note that the lift arm structure  22  includes two sections. First, it includes a fore section indicated generally by the numeral  100 . This section of the lift arm structure is basically straight, that is not substantially curved. Extending further rearwardly from the fore section  100  is an aft section indicated generally by the numeral  102 . The aft section is generally directed downwardly with respect to the fore section  100 . In the case of the particular embodiment shown in the drawings, the aft section  102  is generally curved or arcuate shaped. 
     The lift arm structure of  22  includes a pair of laterally spaced arms  104 . Each arm  104  in the case of the embodiment illustrated herein, is made up or comprises two sections. First, there is a box section  104 A. Secure to the box section  104 A and extending rearwardly therefrom is a curved plate  104 B. Thus, in the embodiment illustrated herein, each lift arm  104  is made up of a box section  104 A and a curved plate  104 B. It is understood, however, that the structure of the lift arm structure and particularly the arms could vary from that structure just described and its structure shown in the drawings. There are, of course, numerous ways that the entire lift arm structure and particularly the arms can be fabricated or made. 
     Connected between the lift arms  104  is a transverse interconnecting member  106 . As seen in FIG. 3, the interconnecting member  106  together with the box sections  104 A form a generally U-shaped frame structure, and wherein the curved plates  104 B are secured to this frame structure and project rearwardly therefrom. 
     To secure the lift arm structure  22  to the hitch frame of  20 , the hitch frame is provided with two sets of plates, each set of plates including plates  112  and  114 . As seen in FIG. 3, the forward portions of the lift arm structure  22  extends into the areas defined between the plates  112  and  114 . A pivot pin  108  extends through the plates  112  and  114  as well as the lift arms  104  that are disposed between the plates. This enables the lift arm structure  22  to pivot up and down with respect to the hitch frame  20 . 
     Disposed on the interconnecting member  106  is a cylinder connecting plate  110 . As will be appreciated from subsequent portions of this disclosure, the bucket actuator, in the form of a hydraulic cylinder, is connected or anchored to the connecting plate  110 . 
     Bucket  24  is pivotally connected to the rear end portions of the lift arm structure  22 . Viewing the bucket  24  in more detail, it is seen that the bucket includes a pair of opposed sides  122  connected together by a curved back  120 . Formed about a terminal edge of the bucket  24  is a blade  124 . To connect the bucket  24  to lift arm structure  22 , there is provided two sets of connecting plates  126 . As seen in FIG. 3 the connecting plates  126  of each set are spaced apart such that the rear portion of the lift arms  104  can be projected between the connecting plates  126 . A pivot pin  128  extends through the connecting plates  126  and through the rear portion of the lift arms  104 . To connect the bucket  24  with the bucket actuator  26 , there is provided a first connecting tab  130  secured centrally to the back  120 . A second connector tab  132  is disposed adjacent the first connector tab. As will be understood from subsequent portions of this disclosure, the second connector tab  132  is utilized when it is desired to place the bucket  24  in a box plate mode. In any event, when the bucket  24  assumes a conventional loader mode, the bucket actuator of  26  is connected to the first connector tab  130 . 
     As pointed out above, various means may be utilized to articulate and move the bucket  24  with respect to the lift arm structure  22 . However, in the embodiment shown herein, the bucket actuator  26  is in the form of a double acting hydraulic cylinder. The hydraulic cylinder includes a housing  150  and a rod  152 . A pair of hydraulic hoses  154  extends from the hydraulic cylinder rearwardly to where they connect to a hydraulic system associated with the tractor  12 . More particularly, as viewed in FIGS. 1-3, the housing  150  of the hydraulic cylinder is pivotally connected to the connecting plate  110  mounted on the interconnecting member  106  of the lift arm structure. The rod  152  of the hydraulic cylinder projects from the housing  152  and when the bucket  24  assumes a loader mode, the rod  152  connects to the first connector tab  130  that is disposed on the curved back  120  of the bucket  24 . 
     To raise and lower the lift arm structure  22  with respect to the hitch frame  20 , the flexible line  28  is connected between the lift arm structure  22  and the draw bar  19  of the tractor. While the flexible line  28  may assume various forms, in the present case, the flexible line  28  comprises a cable. One end portion  160  of the cable is connected through an opening within the connecting plate  110  that forms a part of the lift arm structure  22 . From there, the cable extends forwardly and is threaded through the vertical post member  50  that forms a part of the hitch frame  20 . In particular, the cable is trained around the upper pulley  62  mounted within the vertical post member  50 . From the upper pulley  62  the cable extends generally downwardly and around the rear side of the lower pulley  64 . From the lower pulley  64  the cable extends generally downwardly and rearwardly to where another end portion  162  fastens or connects to the draw bar  19  of the tractor  12 . Thus, it is appreciated that as the rear end loader  10  is raised from the position shown in FIG. 1 to the position shown in FIG. 2, that the cable or flexible line  28  causes the lift arm structure  22  to raise or pivot upwardly with respect to the hitch frame  20 . That is, as the three-point hitch of the tractor including the lower draft links  16  and the upper link  18  are raised up, this means that the hitch frame  20  is also raised. In this process, the cable or flexible line  28  will cause the lift arms  104  to pivot about the axis of the pivot pin connectors  108 . Likewise, when the three-point hitch of the tractor is lowered, the flexible line  28  or the cable will result in the lift arms  104  being rotated clockwise as viewed in FIGS. 1 and 2. 
     Each side  122  of the bucket  24  is provided with an opening  134 . When the bucket is being utilized as a loader, the openings  134  are plugged by a pair of stoppers. However, as will be understood from subsequent portions of this disclosure, a rod or shaft can be inserted through the openings  134  within the sides  122  of the bucket and a pair of forks can be connected to the rod or shaft to convert the bucket  24  into a forklift. See FIG.  7 . 
     As noted above, the bucket  24  can be oriented on the lift arm structure  22  such that it becomes a box blade. This is particularly illustrated in FIGS. 5 and 6. Here a connector bar  170  is interconnected between the hydraulic cylinder  26  and the second connector tab  132  of the bucket  24 . Note that when the bucket  24  assumes the box blade mode, the bucket is effectively rotated clockwise to the position shown in FIG.  5 . Still the particular attitude or orientation of the bucket when it assumes the box blade mode can be varied and adjusted for various applications. 
     In addition, the rear end loader  10  of the present invention is provided with a forklift attachment. This is achieved by inserting a shaft  180  through the openings  134  formed in the sides  122  of the bucket  24 . Shaft  180  is pinned on its opposed ends so as to secure the shaft within the bucket  24 . When inserting the shaft  180  through the openings  134  in the bucket  24 , the shaft is extended through a pair of laterally-spaced forks that are supported about a portion of the bottom of the bucket. Note in FIG. 7 where the shaft  180  extends through the forks  182  and holds the forks  182  in place within the bucket. Note also that the forks  182  extend past the blade  124  such that the forks themselves may be extended under a load to be lifted. 
     There are a number of advantages associated with the rear end loader  10  of the present invention. First, the bucket  24  can be elevated to a substantial height. Generally, the bucket can be elevated to a height as great as 6 feet and this will permit the bucket to dump into the load bed of a conventional pick-up truck. Further, the bucket  24  can be moved through a substantial range of motion about the rear end of the load arm structure  22 . Note FIG. 2, for example. There the bucket in full lines is shown in a conventional digging orientation. However, once there is material within the bucket  24 , the bucket  24  can be rotated counterclockwise to where it assumes the upper dotted line position shown in FIG.  2 . Then, when the bucket  24  is disposed over the load bed of a pick-up or over another dumping site, the bucket  24  can be rotated to its lower dotted line position shown in FIG.  2 . This will completely empty the bucket  24 . Note in this position, that is the lower dotted line position shown in FIG. 2, that the back  120  of the bucket  24  includes a portion having a curvature that is generally parallel to the curvature of a portion of the plates  104   b . In any event, the curvature of the aft section  102  of the lift arm structure  22  enables the bucket  24  to be rotated substantially underneath this structure. This will permit the bucket  24  to assume an even higher elevation and will facilitate the emptying of the bucket  24 . 
     In the box blade mode, shown in FIGS. 5 and 6, the box blade can be provided with tines or spikes that project downwardly to engage the underlying ground. This permits the box blade to be used in certain grading operations. 
     From the foregoing specification and discussion, it is appreciated that the rear end loader  10  of the present invention is particularly adapted to be utilized on small tractors, in the range of 25-60 hp. Although the rear end loader  10  can be used on larger tractors, the loader is particularly useful with small tractors and tractors that have only the capability for one set of hydraulic remotes. In these cases, one can take advantage of the lifting capacity of the three-point hitch and can use the one set of hydraulic remotes to articulate and actuate the bucket  24 . Another advantage of the rear end loader of the present invention is that the loader does not have to be dedicated to a single tractor. The loader of the present invention can be quickly and easily connected and disconnected from the tractor. 
     The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the scope and the essential characteristics of the invention. The present embodiments are therefore to be construed in all aspects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.