Abstract:
A protective shield for use on skid steer loaders and other construction vehicles. The protective shield is composed of metal and functions to protect the tailgate and rear sides of a skid steer loader from dents and abrasions. More particularly, the protective shield is made of a diamond plate metal tailgate panel, which is rotationally molded to define the lower rear door panel, and two diamond plate metal side panels of substantially equal shape for protecting the left and right vertical upright members of the skid steer loader in the area between the rear door and the wheel wells of the skid steer loader.

Description:
FIELD OF INVENTION 
     The present invention relates generally to the creation and use of metal plates as shields for off-road vehicles and, more particularly, to shields for skid steers. 
     BACKGROUND OF THE INVENTION 
     Skid steer loaders, also known as uniloaders, are highly compact off-road vehicles that are steered by driving the wheels on one side of the vehicle at a different speed, in an different direction, or both at a different speed and in a different direction from the wheels on the other side of the vehicle. Because of their compact nature, skid steer loaders operate in environments in which they are required to negotiate around obstacles such as trees and tree stumps, which are likely to cause damage to the skid steer upon impact. Most of the abuse absorbed by skid steers loaders during normal operation is on the rear portion of the vehicle. 
     Operators in the past have mounted protective wooden strips on the rear portion of the vehicle for protection against impacts. These wooden strips are unsightly and relatively ineffective. Other proposed solutions, such as the structure disclosed in U.S. Pat. No. 5,029,918, have used a rear door and an elastomer bumper as protective devices. These proposals are ineffective, however, because they only protect a small portion of the rear end of the vehicle and do not protect the entire rear and lateral sides. Still other proposals are disclosed in the patents discussed below. 
     U.S. Pat. Nos. 5,788,899 and 5,794,805 are directed to double-walled light housings mounting front and rear lights that serve as a fuel tank assembly and as bumpers protecting the upper portion of the vehicle frame. The housings are composed of plastic and define a plurality of horizontally disposed light chambers open away from the frame whereby lights can be selectively mounted in appropriate light chambers. The storage containers are composed of non-metallic parts. 
     U.S. Pat. No. 4,235,466 is directed to a body-side protective molding system that is secured to the vertical metal side panels of an automobile body. The body protective system includes side protective moldings, each made of a roll-formed metallic carrier strip. The strip is bonded at its undersurface to a layer of adhesive tape comprising a two-sided, stick-on neoprene tape. The side of the adhesive tape opposite the carrier strip is used to attach the carrier strip to a surface portion of the automobile body. The metal carrier strip supports a plastic insert that is bonded or mechanically affixed. This system has the disadvantage of being difficult to install and not suitable for off-road vehicles that incur a great deal of damage over a wide surface area on the rear of the vehicle. 
     To overcome the shortcomings of conventional skid steer loaders, a new skid steer loader is provided having a visually attractive shield of high structural integrity that covers the entire rear and lateral side portions of the vehicle and protects the vehicle from impact and abrasions. An object of the present invention is to overcome the disadvantages of the prior art by providing a skid steer loader construction having a protective shield. Another object is to provide a protective shield having a diamond plate metal tailgate panel that is rotationally molded to define the lower rear door panel, and two diamond plate metal side panels of substantially equal shape for protecting the left and right vertical upright members of the skid steer loader in the area between the rear door and the wheel wells. 
     BRIEF SUMMARY OF THE INVENTION 
     To achieve these and other objects, and in view of its purposes, the present invention provides a protective shield (aka bumper beam) for use on skid steer loaders. The shield includes left and right laterally spaced side panel members having laterally facing surfaces and a rear door having a rearwardly facing surface. The protective shield (or bumper beam) is mounted to the rear of the skid steer loader and further includes a diamond plate metal tailgate panel that is rotationally molded to define the lower rear door panel, and two diamond plate metal side panels of substantially equal shape for protecting the left and right vertical upright members of the skid steer loader in the area between the rear door and the wheel wells. 
     The present invention also provides a kit suitable for installation of a protective shield on a skid steer loader which includes a diamond plate metal tailgate panel that is rotationally molded to conform to the first and second elements of the rear door and thus define the lower rear door panel, two diamond plate metal side panels of substantially equal shape for protecting the left and right vertical upright members of the skid steer loader in the area between the rear door and the wheel wells, at least four bolts of a size and dimension suitable for securing the tailgate panel to the skid steer loader plate, and at least eight side bolts of a size and dimension suitable for securing the side panels onto the skid steer using four bolts for each side panel. Alternatively, instead of bolts, the kit may include adhesive suitable for mounting the tailgate panel onto the rear door of the skid steer loader. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures: 
     FIG. 1 is a prospective view of a skid steer loader which combines a conventional bumper with the protective shield in accordance with the present invention; 
     FIG. 2 is a prospective view of a skid steer loader having the protective shield of the present invention; 
     FIG. 3 is a tailgate panel shield according to the present invention; 
     FIG. 4 is a left side panel shield according to the present invention; 
     FIG. 5 is a right side panel shield according to the present invention; 
     FIG. 6 is a relief-cut shield according to the present invention; 
     FIG. 7 is a protective shield according to the present invention; 
     FIG. 8 is a top tailgate protective shield according to the present invention; 
     FIG. 9 is a left side panel protective shield according to the present invention; and 
     FIG. 10 is a right side panel protective shield according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The protective shield (aka bumper beam) of the present invention wraps around and protects the rear portion, including the rear door of skid steer loaders and other construction vehicles. The protective shield offers several advantageous over the prior art. First, the protective shield of the present invention protects a large surface area of the rear portion of the vehicle. In addition, the inventive shield is easy to install, is replaceable, and enhances the overall appearance of the vehicle. 
     Referring to the drawing and particularly to FIGS. 1 and 2, a representative view of a skid steer loader incorporating the principles of the instant invention 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 skid steer loader and facing the forward end in the normal (forward) direction of travel. A skid steer loader  10  comprises a wheeled vehicle having a top, a bottom and a main frame  12 , which is formed by left and right laterally spaced beams or side portions  14 . Each side portion  14 , has an upright member  30 ,  32  at its rear. Two pairs of opposing front and rear wheels  16 ,  18  are rotatably supported by the main frame  12  and are used for over-the-ground travel. An operator&#39;s compartment or cab  20  is located forward of a rear door  24  disposed between the side portions  14 . 
     As is conventional in such vehicles, the wheels  16 ,  18  of the skid steer loader  10  are rotatably driven by hydraulic motors operatively powered from an engine located near the rear of the vehicle and supported by the main frame  12 . Steering of the skid steer loader  10  is accomplished by differential driving of the opposing left and right side wheels  16 ,  18  in a conventional manner through the use of a pair of control sticks (not shown). The main frame  12  defines the operator&#39;s cab  20  in which the operator sits to maneuver the skid steer loader  10 . A work implement, shown in FIGS. 1 and 2 as a bucket  22 , is powered in a conventional manner by hydraulic cylinders (not shown) to locate the work implement immediately forward of the operator&#39;s cab  20 . 
     The rear door (aka rear of the vehicle)  24  extends between the upright members  30 ,  32  and encloses a lower rear portion of the engine compartment. The rear has a first element that extends substantially vertically and a second element that extends from the first element toward the bottom of the skid steer loader at an angle less than 180°. The rear door  24  is mounted by a hinge to one of the upright members  30 ,  32  and is secured to the other upright member  30 ,  32  by a latch mechanism (not shown). A hood  34  is mounted at its top edge to the main fame  12 . A pair of taillights  36 ,  38  are mounted on the rear portion of the vehicle. An elastomer bumper  28  as described in U.S. Pat. No. 5,029,918 is mounted to the left and right lower edges of the rear door  24  as seen in FIG.  1 . The protective shield or protective bumper beam  26  of the present invention is located on the lower portion and on the lateral sides of the rear door  24 , and on the left and right side panels  40  of the vehicle. The bumper beam wraps around the first and second elements of the rear of the skid steer loader. 
     The rear and the side panels of the protective shield  26  are manufactured from metal, preferably diamond aluminum plate. In preferred embodiments of the present invention, the diamond plate has a thickness in the range of 3.175 mm (⅛ inch) to 4.763 mm ({fraction (3/16)} inch). Although a thicker plate is possible, thicker plates needlessly increase the cost of the protective shield  26 . Thinner plates provide insufficient protection against damage to skid steer loader  10 . 
     FIGS. 3 and 4 depict a first embodiment of the protective shield  26  of the present invention. The protective shield  26  consists primarily of a tailgate rear panel  26   a,  as shown in FIG. 3, and two identical side panels  26   b  of the shape shown in FIG.  4 . The rear panel  26   a  has a top  110  and a base  100 . The top  110  has left and right slanted edges  116 ,  120  that end at left and right points  118 ,  122 , respectively. The base  100  has left and right convex sections  104 ,  108 . The left edge  114  begins at the top left point  118  and continues down vertically to a bottom left point  124  before forming a left side-angled edge  102 . Similarly, the right edge  112  begins at the top right point  122  and continues down vertically to a bottom right point  126  before forming a right side-angled edge  106 . Left convex section  104  meets left side-angled edge  102  at a junction  128 ; similarly, right convex section  108  meets right side-angled edge  106  at a junction  130 . 
     Upon installation of the rear panel  26   a  onto the vehicle, the left convex section  104  is welded to the left side-angled edge  102 , and the right convex section  108  is welded to the right side-angled edge  106  using conventional welding procedures well known to those of skill in the art. The rear panel  26   a  is centered on the rear door  24  of the vehicle such that the base  100  is flush with the bottom edge of the rear door  24  and the left edge  114  and right edge  112  are flush with the left and right edges of the rear door  24 , respectively. Junctions  128 ,  130  permit the rear panel  26   a  to bend along an imaginary horizontal line connecting junctions  128 ,  130  and, therefore, to conform to the lower front portion of rear door  24 . Junctions  128 ,  130  also permit the rear panel  26   a  to bend along an imaginary vertical line extending through the junctions  128 ,  130  and, therefore, to conform to the sides of rear door  24 . It may be necessary to tap the corners of the rear shield  26   a  with a rubber mallet to facilitate application of the shield  26  to the vehicle. 
     The rear panel  26   a  of shield  26  is then secured in place using fasteners disposed generally in each comer of the rear panel  26   a  using methods well known to those of skill in the art. Any one of a number of types of conventional fasteners are suitable; bolts are preferred. The number of bolts used to fasten the rear panel  26   a  of the protective shield  26  to the skid steer loader  10  is not critical. In preferred embodiments, however, at least four bolts are used to fasten the shield  26  onto the vehicle. The bolts should be of sufficient size to ensure adequate fastening of the rear panel  26   a  to the vehicle. In preferred embodiments, the bolts are about 6.3 to 12.7 mm (¼ to ½ inch) in size. In a most preferred embodiment, the bolts are about 8 mm ({fraction (5/16)} inch) in size. An elastomer bumper  28  may be applied directly on top of the shield  26  as shown in FIG.  1 . 
     Depicted in FIG. 4, the left and right side panels  26   b  are mirror images of one another. Each side panel  26   b  has a top  210 , a base  212 , a straight side  202 , and a concave side  204 . The concave side  204  extends from a pointed top edge  208  down in a generally vertical manner to a curved bottom edge  206 . To install each side panel  26   b,  the base  212  is positioned such that it is flush with the bottom edge of one of the upright members  30 ,  32  of the vehicle with the concave side  204  of the side panel  26   b  facing the wheel well. A hole is drilled at each corner of the side panel  26   b  and in corresponding positions of the vehicle. The side panel  26   b  is secured into place using fasteners (e.g., bolts) that extend through each of the correspondingly positioned holes. 
     The number of bolts used to fasten each side panel  26   b  of the protective shield  26  to the skid steer loader  10  is not critical. In preferred embodiments, however, at least four bolts are used to fasten each side panel  26   b  to the vehicle. The bolts should be of sufficient size to ensure adequate fastening of the side panels  26   b  to the vehicle. In preferred embodiments, the bolts are about 8 mm ({fraction (5/16)} inch) in size. 
     Each side panel  26   b  may be positioned flush with the wheel well. Alternatively, a small gap may intentionally be left between the side panels  26   b  and the wheel wells. Such a gap helps to prevent debris from prying the side panel  26   b  away from the vehicle upon contact. 
     FIG. 5 illustrates a second embodiment of the side panel  26   b  of the shield  26  of the present invention. As illustrated in FIG. 5, side panel  26   b  has an arc  214  cut into the concave side  204 . Arc  214  is shaped to accommodate any protrusions of the vehicle that might otherwise prevent side panel  26   b  from being affixed to and lying flush against the vehicle. Other differences between the embodiments of the side panel  26   b  illustrated in FIGS. 4 and 5 include shape variations in side panel  26   b  adjacent curved bottom edge  206  and pointed top edge  208 . 
     FIG. 6 illustrates a third embodiment of the side panel  26   b  of the shield  26  of the present invention. As illustrated in FIG. 6, side panel  26   b  has an opening  216 . Opening  216  is designed to accommodate a preexisting feature of the vehicle that may protrude outwardly from the frame of the vehicle. 
     FIG. 7 illustrates another embodiment of the shield  26  of the present invention. This embodiment is suitable for models of skid steer loaders  10  having a grill located on the rear door  24  of the vehicle. The tailgate or rear panel  26   a  has a top  710 , a base  712 , a left vertically projecting edge  714 , and a right vertically projecting edge  716 . In other words, the rear door of the skid steer loader extends laterally towards the left and right vertical upright members in an angle less than 180°. The bumper beam is rotationally molded to conform to the lateral extensions of the rear door. The left and right vertically projecting edges  714 ,  716  extend upwards perpendicularly from the base  712  such that a substantially rectangular or square cavity  715  is formed between the vertically projecting edges  714 ,  716 . The cavity  715  is designed to accommodate a grill located on the rear door  24  of the vehicle. 
     The left vertically projecting edge  714  has a relief void  718  on the outer left side designed to accommodate a preexisting feature of the vehicle that may protrude outwardly from the rear door  24  of the vehicle (such as a latch). Similarly, the right vertically projecting edge  716  has a relief void  720  located on the outer right side designed to accommodate a preexisting feature of the vehicle that may protrude outwardly from the rear door  24  of the vehicle (such as a door hinge). A notch  730  is provided in the top left corner of the rear panel  26   b  to facilitate a protruding object of the vehicle (such as a door handle). A pair of grooves  740  are located on the left and right bottom corners of the base  712 . The tops  722 ,  722 ′ and the bottoms  724 ,  724 ′ of the grooves are welded together before installation of the shield  26  onto the vehicle and are designed to rotationally conform the shield  26  to the rear door  24  of the vehicle. 
     The side panels  26   b  are of a substantially wing-like shape. The left and right side panels  26   b  have a relief cut arc  750  located in the upper left corner of each side panel  26   b.  The arcs  750  are designed to accommodate a protruding preexisting feature of the vehicle (such as a loading arm pin). Each side panel  26   b  has an inner edge  755 ,  755 ′ and an outer edge  765 ,  765 ′. The inner edge  755 ′ of the right side panel  26   b  has a relief cut void  762  that corresponds to the relief cut void  720  on the rear panel  26   a.  The relief cut void  762  is designed to accommodate a preexisting outwardly protruding object on the vehicle (such as a door hinge). To install the side panels  26   b,  the bases  764 ,  764 ′ of the side panels  26   b  are positioned such that they are flush with the bottom edges of the upright members  30 ,  32  of the vehicle and such that the outer edges of the side panels  26   b  face the wheel well of the vehicle. A hole is drilled at each corner of the side panel  26   b  and in corresponding positions of the vehicle. The side panel  26   b  is secured in place using bolts that are extended through each of the correspondingly positioned holes. 
     FIGS. 8,  9 , and  10  illustrate another embodiment of the present invention. The rear panel  26   a  of FIG. 8 has a substantially rectangular shaped body  810  defining the top  110 , right edge  112 , and left edge  114  of the rear panel  26   a.  The body  810  also has integral, one-piece, monolithic mirror image side edges  812 ,  812 ′ projecting from the body  810 . The projecting edges  812 ,  812 ′ do not extend to the full width of the body  810 . Rather, projecting edges  812 ,  812 ′ extend from about the midpoint of the side edges  112 ,  114  of the body  810 , forming a right angle to the side edges  112 ,  114 . 
     Each projecting edge  812 ,  812 ′ extends outward from side edges  112 ,  114  parallel to the base  100  of rear panel  26   a  before angling downward at top junction points  814 ,  814 ′ and bottom junction points  816 ,  816 ′ to the angled, flat faces  820 ,  820 ′. The top angled portions  822 ,  822 ′ and the bottom angled portions  824 ,  824 ′ form right angles with faces  820 ,  820 ′. This shape facilitates the use of an elastomer bumper  28  simultaneously with the protective shield  26  on the same vehicle as shown in FIG.  1 . 
     The side panels  26   b  of FIGS. 9 and 10 each have a small notch  830  located on the straight sides  202  of the side panels  26   b.  The top and bottom edges of the notch  830  are welded together before installation of the shield  26  onto the vehicle and are designed to rotationally conform to the edges of the upright members  30 ,  32  of the vehicle on older skid steer models. 
     The present invention is suitable for use on all commercially available skid steers loaders including, but not limited to, all Bobcat, Case, Gehil, Mustang, and New Holland skid steer loaders. Specific example vehicles include the Bobcat 700 series models, Bobcat 800 series models, and Case models 1840 and 1845. 
     Some skid steers, such as the Case 1840 or 1845 models, have fuel tanks located immediately adjacent to the upright members  30 ,  32  of the vehicle. This location of the fuel tanks necessitates an alternative installation process of the protective shield  26  of the present invention. Each side panel  26   b  is glued onto the vehicle using 3M 1099 brand adhesive (available from Minnesota Mining &amp; Manufacturing Co.). Other adhesives have proven to be ineffective for purposes of the present invention. The entire surface of the protective shield  26  and the corresponding surface area of the vehicle are first sanded using coarse grade sandpaper until bare metal is exposed and visible and then cleaned with any brand of denatured alcohol using conventional application methods known to one of skill in the art. Following application of the denatured alcohol, the adhesive is applied over the entire sanded surface area of the protective shield  26  and the corresponding area on the vehicle. The adhesive is allowed to sit for approximately 10 minutes. The protective shield  26  is then applied to the vehicle and secured overnight by clamps such as spring clamps or “C-clamps.” The type of clamp used is not critical to the present invention and need only be of sufficient size and shape to ensure adequate contact of the protective shield  26  to the vehicle. 
     For application of the rear panel  26   a  of the shield  26  to the rear door  24 , two bottom bolts are first removed from the grill. The rear panel  26   a  is centered on the rear door  24  of the vehicle such that the base  100  is flush with the bottom edge of the rear door  24 . Two holes are marked and drilled corresponding to the location of the bolts from the oil cooler of the vehicle. The rear panel  26   a  is then secured in place using bolts of suitable size and using methods well known to those of skill in the art. At least two holes are then drilled in the upper portion of the rear panel  26   a  and rear door  24  of the vehicle. These holes are then used to bolt rear panel  26   a  to the vehicle using methods well known to those of skill in the art. 
     Although illustrated and described above with reference to certain specific embodiments, the present invention is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.