Abstract:
A hydraulically operated attachment for a skid loader or the like provides for the easy removal of large trees and the lifting of other heavy objects. The lift attachment includes a frame, a base portion extending forward from the bottom of the frame, a lifter portion hingedly attached to the top of the frame, and a hydraulic cylinder for moving the lifter portion from a down position to a raised position.

Description:
FIELD OF THE INVENTION 
     The present invention pertains generally to attachments for skid loaders, and, more particularly, to hydraulically operated attachments for skid loaders that are adapted for digging and lifting, such as for digging out and lifting rooted trees or other objects. 
     BACKGROUND OF THE INVENTION 
     A skid loader or skid steer loader is a rigid frame, engine-powered machine with lift arms used to attach a wide variety of labor-saving tools or attachments. Though sometimes they are equipped with tracks, skid-steer loaders typically are four wheel drive vehicles with the left-side drive wheels independent of the right-side drive wheels. By having each side independent of the other, wheel speed and direction of rotation of the wheels determine the direction the loader will turn. Skid steer loaders are capable of zero-radius, “pirouette” turning, which makes them extremely maneuverable and valuable for applications that require a compact, agile loader. 
     The conventional bucket of many skid loaders can be replaced with a variety of specialized buckets or attachments, many powered by the loader&#39;s hydraulic system. All newer skid loaders have a connection for external hydraulic systems, so that hydraulics on the attached equipment can be connected readily to the loader&#39;s hydraulic system. Such skid loader attachments include backhoes, hydraulic breakers, pallet forks, angle brooms, sweepers, augers, mowers, snow blowers, stump grinders, tree spades, trenchers, dumping hoppers, rippers, tillers, grapplers, tilters, rollers, snow blades, wheel saws, cement mixers, and wood chippers. 
     With so many convenient attachments available, just about anyone who has access to skid loader wants to use it for as much of their work as possible. However, no currently available skid loader attachment is capable of removing large trees that are rooted in the ground. For this type of work a bulldozer or other large machine typically is required. 
     A skid loader attachment sold as the “Extractor” uses the concept of hydraulic force against the ground to pull out or lift an object. This device, however, requires that a bush or small tree to be lifted by the device be attached to the device using a chain. Thus, using this device, it would take several minutes for the operator to pull up to a small tree, get out of the skid loader, get back in and seat-belted, and then lift the tree, maybe. Furthermore, this attachment is only useful for pulling small trees and shrubs. A wise operator would not even attempt to remove a large tree by the roots using such an attachment. 
     Another skid loader attachment product that may be used to pull out trees is the Extreme stump bucket. But this product does not employ a hydraulic cylinder and is generally ineffective for this purpose. 
     What is desired, therefore, is an attachment for a skid loader that is no larger than an ordinary skid loader bucket but that allows a user to lift out large trees at the roots quickly and easily and to lift other heavy objects as well. 
     SUMMARY OF THE INVENTION 
     The present invention provides a lift attachment for skid loaders that may be used to dig under and hydraulically lift out a tree and its roots quickly. A skid loader attachment in accordance with the present invention is able to remove trees at the roots in seconds without the operator ever having to leave his seat in the skid loader. Using a skid loader attachment in accordance with the present invention even large trees can be removed by the roots and carried away in minutes. 
     A lift attachment for skid loaders in accordance with the present invention operates on the same principle as a hydraulic floor jack. Two protruding tines of a moveable lifter portion of the lift attachment are pushed into the ground and hooked under a tree. Then an attached hydraulic cylinder is used to lift the lifter portion and thus to lift the tree out of the ground. For very large trees an operator would work the lift attachment around the base of the tree to first pull up all of the large roots one-by-one, and then take out the whole tree. Small trees or shrubs can just be pinched and pulled out without digging under them, even ones on the other side of a fence. Thus, a lift attachment in accordance with the present invention can be taken into a lot or a fencerow and used to remove one tree without destroying several others or the fence. In many cases a skid loader with a lift attachment in accordance with the present invention is capable of rooting out a tree without even using the hydraulics of the device. When the tree is on the ground the hydraulics of a lift attachment in accordance with the present invention can be used to raise the lifter portion to grab the tree and carry it away. The simplicity of use, capability, and speed of a lift attachment in accordance with the present invention is beyond anything currently known or available. Other devices that can dig under a tree of comparable size cannot match the speed and ability of a lift attachment in accordance with the present invention. 
     A lift attachment in accordance with the present invention is also particularly well adapted to lifting heavy objects on soft ground with ease and speed. Thus, a lift attachment in accordance with the present invention also doubles as a jack for large or small machinery on soft ground. A lift attachment in accordance with the present invention can lift objects of several tons on soft or unstable ground, such as a piece of farm machinery with a flat tire in a sodden field, in just seconds. 
     Further objects, features, and advantages of the invention will appear more fully from the following detailed description of the invention made in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustration of an exemplary lift attachment in accordance with the present invention, showing a lifter portion thereof in a down position. 
         FIG. 2  is a perspective view illustration of the exemplary lift attachment of  FIG. 1 , showing the lifter portion thereof in a raised or lifting position. 
         FIG. 3  is a rear perspective view illustration of the exemplary lift attachment of  FIG. 1 . 
         FIG. 4  is a side view illustration of an exemplary lift attachment in accordance with the present invention shown attached to a skid loader and in use lifting out a tree at its roots. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An exemplary lift attachment  10  in accordance with the present invention now will be described in detail, beginning with  FIGS. 1-3 . The main components of a lift attachment  10  in accordance with the present invention include a frame  12 , a horizontal base portion  14  fixedly attached to the frame  12 , and a moveable lifter portion  16  moveably attached to the frame  12  and adapted to be actuated by a hydraulic cylinder  18 . 
     The frame  12  of the lift attachment  10  provides the support structure for the other components of the lift attachment  10 , as well as the structure by which the lift attachment  10  is mounted to a skid loader. As illustrated best in  FIG. 3 , the frame  12  may be formed from top  20  and bottom  22  elongated horizontal frame pieces that are parallel to each other, separated from each other, and joined together by separated parallel vertical frame pieces  24  and  26  that are perpendicular to the top  20  and bottom  22  pieces and positioned at or near the ends of the top  20  and bottom  22  pieces. The top  20 , bottom  22 , and vertical  24 ,  26  frame pieces thus form a substantially rectangular frame structure  12 . For exemplary purposes only, the top  20  and bottom  22  frame pieces may be formed of 2 inch by 3 3/16 inch hollow steel tubing and may be approximately 46 inches long. The vertical frame pieces  24  and  24  may be made of the same steel tubing material as the top  20  and bottom  22  pieces and welded at the ends thereof to the top  20  and bottom  22  pieces to form the frame  12 . If the vertical frame pieces  24  and  26  are selected to be approximately 13 inches long, the overall size of the frame  12  will be approximately 46 inches wide by 19 inches high. It should be understood, however, that any other appropriate materials may be used to form a frame  12  having the same or different dimensions from those provided by example herein. 
     Appropriate structures are provided on a back side of the frame  12  whereby the frame  12 , and thus the entire lift assembly  10 , is mounted on the lift arms of a skid loader. In the present example, such mounting structures include two downward opening pocket structures  28  that are formed on the back side of the top frame piece  20  and two downward slanting plate structures  30  formed on the back side of the bottom frame piece  22 . These mounting structures  28  and  30  are positioned with respect to each other on the frame  12  so as to be engaged by corresponding mounting structures on the lift arms at the front end of a skid loader, whereby the entire lift attachment  10  in accordance with the present invention may be mounted on the skid loader for use. The exemplary mounting structures  28  and  30  may be formed from sheet steel material that is cut and welded to form the structures  28  and  30  that then may be welded to the frame  12  in the appropriate positions. It should be understood, however, that various other and different mounting structures may be provided on the frame  12 , and made from other appropriate materials and by other appropriate methods, depending upon the corresponding mounting structures provided on the skid loader to which the lift attachment is to be mounted. 
     The horizontal base portion  14  extends perpendicularly from the front side (the side opposite to the side to which the mounting structures  28  and  30  are attached) of the frame  12 . The horizontal base portion  14  extends from the center of the bottom piece  22  of the frame  12  and may be formed of two separated parallel horizontal base portion leg pieces  32 . For example, the base portion leg pieces  32  may be made of 2 inch by 3 3/16 inch steel tube that is attached to the bottom piece  22  of the frame  12  by welding. The base portion leg pieces  32  preferably may be approximately 32 inches long and separated from each other by a distance of approximately 8 inches. The distal ends  34  of the horizontal leg pieces  32  preferably may be angled such that the leg pieces  32  are somewhat longer along the bottom thereof than along the top thereof, thereby providing a pointed distal end of the base portion  14 . It should be understood that other appropriate materials may be used to form leg pieces  32  having the same or different dimensions from those described herein. 
     A connector piece  36 , which may be made of the same steel tube material as the leg pieces  32 , is welded between the leg pieces  32  at the distal ends thereof  34  at an angle that corresponds to the angled distal ends  34  of the leg pieces  32 . The connector piece  36  provides support at the distal end  34  of the horizontal base portion  14  and forms a backstop for the lifter portion  16 . 
     Further support for the base portion  14  may be provided by two straight support pieces  38 . Each support piece  38  is connected at one end along the length of one of the leg pieces  32  (e.g., approximately 11 inches from the distal end  34  of the leg piece  32 ) and at the other end to the top piece  20  of the frame  12 . Each support piece  38  may be implemented, for example, using a 2 inch by ⅜ inch steel bar or similar structure cut to the appropriate length and welded at the ends thereof to the leg pieces  32  and the top piece  20  of the frame  12 . It should be understood that other structures and materials may be used to provide support for the base portion  14  as appropriate and desired. 
     The moveable lifter portion  16  is moveably attached at one end thereof to the top piece  20  of the frame  12  on the frond side and at the center thereof. In its down or lowered position, the lifter  16  extends perpendicularly from the top piece  20  and parallel with the base portion  14  for a distance of approximately 12 inches. The lifter  16  then extends downward from this point (e.g. for approximately 24 inches) at an angle to a position adjacent to the backstop connector piece  36  on the base portion  14 . The lifter  16  then extends forward, e.g. for an additional approximately 8 inches, from the backstop  36 . The distal end  40  of the lifter  16  preferably is pointed. 
     The moveable lifter portion  16  may be formed from 2 inch by 3 3/16 inch steel tubing that is cut and welded together, or otherwise formed, into two lifter tines  42  having the shape as just described. The two lifter tines  42  are connected together by a plurality (preferably at least two) cross pieces  44 , that may be made of the same material as the tines  42  and that are welded between the tines  40  at a plurality of locations along the length thereof. With the cross pieces  44  selected to be approximately 4 inches long, the overall width of the lifter portion  16  will be approximately the same as the distance between the leg pieces  32  forming the base portion  14 . Thus, when in the down position, the lifter tines  40  will rest against the backstop piece  36  between the leg pieces  32 . 
     The lifter portion  16  is attached in a hinged relation at the proximal end thereof to the frame  12  at or near the center top thereof. For example, the lifter portion  16  preferably may be attached in a hinged relation to the front side of the top frame piece  20  at the center thereof. Thus, a hinge bracket preferably is provided for this purpose on the top frame piece  20 . 
     As illustrated in  FIGS. 1 and 2 , this top hinge bracket may be formed from two L-shaped hinge bracket pieces  46 . The L-shaped hinge bracket pieces  46  are attached to the top frame piece  20  at one side of the L, with the other side of the L extending forward perpendicularly from the top frame piece  20 . Hinge pin apertures are formed in the extending portions of the bracket pieces  46  and the bracket pieces  46  are attached to the top frame piece  20  such that the distance between these hinge pin apertures is slightly larger than the width of the proximal end of the lifter portion  16 . 
     Alternatively, and preferably, the top hinge bracket may be formed as a single bracket piece  48 , as illustrated in  FIG. 3 . In this case, the bracket piece  48  includes an elongated base portion  50  and two extending portions  52  extending perpendicularly from the base portion. Hinge pin apertures are formed in the extending portions  52  of the bracket piece  48 , and the extending portions  52  are positioned separated along the base portion  50  such that the distance between the hinge pin apertures is slightly larger than the width of the proximal end of the lifter portion  16 . For example, the base portion  50  may be approximately 12 inches long, with each extending portion  52  attached thereto approximately one inch in from each end of the base portion. The bracket piece  48  is attached to the front side of the top frame piece  20  via the elongated base portion  50  thereof such that the extending portions  52  extend forward perpendicularly from the top frame piece  20 . 
     The bracket pieces  46 ,  48  may be formed from flat iron pieces, e.g., 3 inch wide by ⅜ inch thick flat iron pieces, that are cut and welded together or otherwise formed into the desired shape of the bracket pieces  46 ,  48 . The bracket pieces  46 ,  48  so formed may then be welded to the front side of the top frame piece  20 . It should be understood, however, that other bracket pieces having different dimensions, made of different materials, made by different methods, and/or attached to the top frame piece  20  in a different manner from that described herein may also be used. 
     The distal end of the lifter portion  16  is moveably attached to the bracket pieces  46  or  48  in a hinged relationship via a hinge pin  54 . Hinge pin apertures are formed through the lifter portion  16  near the proximal end thereof. These hinge pin apertures in the lifter portion  16  are aligned with the hinge pin apertures formed in the top hinge brackets  46  or  48  by positioning the proximal end of the lifter portion  16  between the extending portions of the top hinge bracket  46  or  48 . The hinge pin  54  is then extended through the aligned hinge pin apertures in the lifter portion  16  and in the top hinge bracket  46  or  48  to attach the lifter portion  16  in a moveable hinged relation to the frame  12 . 
     A bushing  56  may be mounted between the two lifter tines  42  at the proximal end of the lifter portion  16 . The bushing  16  may be formed from a tubular material, e.g., a 1 inch diameter piece of tubing, that is welded to the lifter tines  42  such that the tube passageway is aligned with the hinge pin apertures formed in the lifter tines  42  at the proximal end of the lifter portion  16 . Thus, when the lifter portion  16  is mounted to the frame  12  in the manner described, the hinge pin  54  passes through the bushing  56 . The bushing thus provides additional structural support for the lifter tines  42  at the hinge point. 
     The hydraulic cylinder  18  is attached in a hinged relation at one end thereof to the frame  12 , at or near the bottom of the frame  12 , and at the other end thereof to the lifter portion  16 , near the distal end of the lifter portion  16 . Any appropriate commercially available hydraulic cylinder  18  may be used. The size and capability of the hydraulic cylinder  18  selected will depend upon the desired size and capability of the lift attachment in accordance with the present invention with which it is to be used. Preferably, the hydraulic cylinder  18  selected includes the appropriate hydraulic connectors for coupling to the hydraulic system of a skid loader to which it is to be attached. 
     The hydraulic cylinder  18  may be attached at a first end thereof to the bottom frame piece  22  near the center thereof. For this purpose an appropriate bracket  58  may be attached to the front side of the bottom frame piece  22  at or near the center thereof. The bracket  58  includes a hinge pin aperture formed therein such that the first end of the hydraulic cylinder  18  may be attached in a moveable hinged relation to the bracket  58 , and thus to the frame  12 , by use of a hinge pin  60  extending though the hinge pin aperture. The bracket  58  may be formed from flat iron pieces in the manner of the hinge brackets  46 ,  48  described above and welded to the bottom frame piece  22 . It should be understood, however, that other structures, possibly made of different materials, made by different methods, and/or attached to the frame  12  in a different manner, may be used to attach the first end of the hydraulic cylinder  18  to the frame in a hinged relation, depending particularly upon the mounting structure that is provided at the first end of the hydraulic cylinder  18  by the manufacturer thereof. 
     It should be noted that in the exemplary embodiment described and illustrated the first end of the hydraulic cylinder  18  is attached to the frame  12  at a position thereon adjacent to the base portion  14 . Alternatively, the first end of the hydraulic cylinder  18  may be attached to the base portion  14  at a position thereon adjacent to the frame  12 . In either case the position of the first end of the hydraulic cylinder  18  is substantially the same and the desired leverage is achieved. 
     The second end of the hydraulic cylinder  18  preferably is attached in a hinged relation to the lifter portion  16  near the distal end thereof. By this it is meant that the second end of the hydraulic cylinder  18  is attached to the lifter portion  16  at a position along the length of the lifter portion  16  that is closer to the distal end of the lifter portion  16  than to the center of the lifter portion along the length thereof. For example, the second end of the hydraulic cylinder  18  preferably is attached to lifter portion  16  at a position on the lifter portion  16  that is located just above the backstop piece  36  when the lifter portion  16  is in the down position, as illustrated in  FIG. 1 . For this purpose an appropriate mounting bracket  62  may be attached to the lifter portion  16  at the desired position thereon. The mounting bracket  62  has a hinge pin aperture formed therein, such that the second end of the hydraulic cylinder  18  may be attached in a moveable hinged relation to the mounting bracket  62 , and thus to the lifter portion  16 , by a hinge pin  64  extended through hinge pin aperture. The mounting bracket  62  may be formed in the manner of the hinge brackets  46 ,  48  described above and welded to the lifter portion  16  in the desired location. It should be understood, however, that other structures, possibly made of different materials, made by different methods, and/or attached to the lifter portion  16  in a different manner, may be used to attach the second end of the hydraulic cylinder  18  to the lifter portion  16  in a hinged relation, depending particularly upon the mounting structure that is provided at the second end of the hydraulic cylinder  18  by the manufacturer thereof. 
     Exemplary operation and use of a lift attachment  10  in accordance with the present invention now will be described with reference to  FIG. 4 . For use, the lift attachment  10  is attached to the lift arms at the front end of a conventional skid loader  70  or similar vehicle, e.g., by use of the appropriate mounting structures  28 ,  30  on the back side of the frame  12 . When so attached to a skid loader  70 , the base portion  14  and lifter portion  16  extend forward from the skid loader, and the entire lift attachment  10  may be elevated and tilted by operation of the front end of the skid loader  70  in a conventional manner. The hydraulic cylinder  18  of the lift attachment  10  is coupled, via an appropriate hydraulic coupling structure  72 , to the hydraulic system of the skid loader  70 , such that the hydraulic cylinder  18  may be actuated by an operator in the cab of the skid loader to raise and lower the lifter  16  between a down position ( FIG. 1 ) and a raised position ( FIG. 2 ). 
     In use, for example, to remove a large tree  74 , the distal end of the lifter  16  is driven into the ground underneath the tree, with the lifter  16  in the down position, by operation of the skid loader  70 . The pointed and angled distal ends of the lifter  16  and base portions  14  facilitate driving the lifter  16  into the ground under the tree  74 . (For very large trees, the lifter  16  may be driven into the ground around the tree  74  at several points, thereby to sever the major tree roots before removing the tree  74  using the lift attachment  10  in accordance with the present invention.) With the lifter portion  16  in position under the tree  74 , the hydraulic cylinder  18  is actuated to move the distal end  40  of the lifter  16  upward to remove the tree  74  from the ground at the roots with minimal impact on the surrounding ground. The base  14  of the attachment  10 , which remains against the ground, provides for operation of the hydraulic force of the cylinder  18  between the ground and the lifter portion  16 . The position at which the hydraulic cylinder  18  is attached to the lifter portion  16  (near the distal end  40  thereof) and to the frame  12  (adjacent to the base  14 ) provides enhanced leverage for the hydraulic force applied. In combination, this provides for increased lifting ability, which allows even very large trees to be removed with relative ease using a lift attachment  10  in accordance with the present invention. 
     A lift attachment  10  in accordance with the present invention thus allows farmers, landscapers, and other operators to remove large trees from along fence lines, along waterways, in a woods, or in other locations where otherwise much larger machinery, that would also likely cause significant collateral damage, would be needed. Small trees can be simply pinched and pulled out using the attachment  10 . Larger trees can be dug under and then take out by operation of the hydraulic cylinder  18  in the manner described above. A removed tree can then be grabbed using the attachment  10 , e.g., between the distal ends of the base  14  and the lifter  16 , and carried off to a pile. All of these operations can be performed by an operator without leaving his seat in the skid loader  70  to which the attachment  10  is attached. 
     It should be understood that a lift attachment  10  in accordance with the present invention may be used for many applications other than tree removal. For example, other large objects, such as large farm equipment (e.g., a tractor or combine) can be picked up and moved using a lift attachment  10  in accordance with the present invention. 
     It is understood that the invention is not confined to the particular construction and arrangement of parts herein illustrated and described, but embraces such modified forms thereof as come within the scope of the following claims.