Patent Publication Number: US-7914082-B2

Title: Apparatus for a vehicle for dumping and providing ground access

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The application is a divisional of U.S. patent application Ser. No. 11/149,344 filed Jun. 9, 2005 (now U.S. Pat. No. 7,401,860, issued Jul. 22, 2008), the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to apparatus for a vehicle for dumping and providing ground access, such as a bed of a pickup truck. 
     BACKGROUND OF THE INVENTION 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     People commonly transport heavy loads within the bed of a pickup truck. Depending on the load (e.g., riding lawn mower, four wheel all-terrain vehicle, motorcycle, etc.), it may be necessary to back the truck up to a platform at an elevation approximately equal to that of the bed in order to slide or roll the load onto/off of the bed. As an alternative, the load may be slid or rolled onto a ramp positioned between the ground and the bed during loading or unloading. In addition, sand, gravel, dirt, and rock are commonly hauled in a pickup truck bed. And, although some designs may permit limited tilting of the bed to facilitate unloading, such designs are usually limited to low tilt angles that are not sufficient for dumping. In which case, the load must still be shoveled or otherwise pushed off the tilted bed. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, an apparatus generally includes a dump frame pivotably coupled to a vehicle&#39;s chassis for pivotal movement relative to the chassis. The apparatus also includes a slide frame for supporting a load. The slide frame is slidably coupled to the dump frame such that the slide frame is longitudinally slidable relative to the dump frame, and such that the slide frame pivots along with the dump frame relative to the chassis. The apparatus further includes at least one slide frame actuator for causing sliding movement of the slide frame, and at least one dump frame actuator for causing pivotal movement of the dump frame. 
     According to another aspect of the present invention, an apparatus generally includes a dump frame pivotably coupled to a vehicle&#39;s chassis for pivotal movement relative to the chassis. The apparatus also includes a slide frame for supporting a load. The slide frame is slidably coupled to the dump frame such that the slide frame is longitudinally slidable relative to the dump frame, and such that the slide frame pivots along with the dump frame relative to the chassis. The apparatus further includes at least one seal for substantially sealing at least one sliding surface to thereby inhibit the ingress of foreign objects and debris to the sliding surface. 
     Further aspects and features of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a truck having an apparatus for dumping and providing ground access according to one exemplary embodiment of the invention, and illustrating the apparatus in an intermediate load/dump position; 
         FIG. 2  is a front view of the truck shown in  FIG. 1  with the cab removed for clarity; 
         FIG. 3  is a side view of the truck shown in  FIG. 1  and illustrating the apparatus in a transport position; 
         FIG. 4  is a side view of the truck shown in  FIG. 1  and illustrating the apparatus in an intermediate dump position; 
         FIG. 5  is a side view of the truck shown in  FIG. 1  and illustrating the apparatus in a dump position; 
         FIG. 6  is a side view of the truck shown in  FIG. 1  and illustrating the apparatus in a slidably extended position; 
         FIG. 7  is a side view of the truck shown in  FIG. 1  and illustrating the apparatus in an intermediate load/dump position; 
         FIG. 8  is a side view of the truck shown in  FIG. 1  and illustrating the apparatus in a load position; 
         FIG. 9  is a top view of the truck shown in  FIG. 1  and illustrating the apparatus in a transport position; 
         FIG. 10  is a top view of the truck shown in  FIG. 1  and illustrating the apparatus in a slidably extended position; 
         FIG. 11  is a side view of the truck shown in  FIG. 1  wherein the truck includes a bed shown in the transport position; 
         FIG. 12  is a side view of the truck shown in  FIG. 11  and illustrating the bed in an intermediate dump position; 
         FIG. 13  is a side view of the truck shown in  FIG. 11  and illustrating the bed in a dump position; 
         FIG. 14  is a side view of the truck shown in  FIG. 11  and illustrating the bed in a slidably extended position; 
         FIG. 15  is a side view of the truck shown in  FIG. 11  and illustrating the bed in an intermediate load/dump position; 
         FIG. 16  is a side view of the truck shown in  FIG. 11  and illustrating the bed in a load position; 
         FIG. 17  is a top view of the truck shown in  FIG. 11  an illustrating the bed in a transport position; 
         FIG. 18  is a top view of the truck shown in  FIG. 11  and illustrating the bed in a slidably extended position; 
         FIG. 19  is rear view of the truck shown in  FIG. 11  and illustrating the bed in a transport portion; 
         FIG. 20  is a rear transverse cross-sectional view of the truck shown in  FIG. 11 ; 
         FIG. 21  is a rear transverse cross-sectional view of a portion of the truck as shown in  FIG. 20 ; 
         FIG. 22  is a rear transverse cross-sectional view of a portion of  FIG. 21 ; 
         FIG. 23  is a side view of a truck having a bed (with one side rail removed for clarity), a bed-mounted winch, and an apparatus for dumping and providing ground access according to one exemplary embodiment of the invention, and illustrating the apparatus and bed in a load position; 
         FIGS. 24A and 24B  are side views of the truck shown in  FIG. 11  illustrating an exemplary manner by which the bed can be removed from and attached to the dump/slide apparatus; 
         FIG. 25  is a top view of a truck having an apparatus for dumping and providing ground access that includes a scissors hoist according to another exemplary embodiment of the invention, and illustrating the apparatus in a transport position; 
         FIG. 26  is a top view of the truck shown in  FIG. 25  and illustrating the apparatus in a slidably extended position; 
         FIG. 27  is a side view of the truck shown in  FIG. 25  wherein the truck includes a bed shown in the transport position; 
         FIG. 28  is a side view of the truck shown in  FIG. 27  and illustrating the bed in an intermediate dump position; 
         FIG. 29  is a side view of the truck shown in  FIG. 27  and illustrating the bed in a dump position; 
         FIG. 30  is a side view of the truck shown in  FIG. 27  and illustrating the bed in a load position; 
         FIG. 31  is a transverse cross-sectional view of a portion of an apparatus for dumping and providing ground access according to another exemplary embodiment of the invention in which the apparatus includes at least one seal for substantially sealing an interface between the slide frame and the dump frame; 
         FIG. 32  is a transverse cross-sectional view of a portion of an apparatus for dumping and providing ground access according to another exemplary embodiment of the invention in which a top portion of the slide frame extends across a portion of the dump frame thereby substantially sealing an interface between the slide frame and the dump frame; 
         FIG. 33  is a top view of a truck having an apparatus for dumping and providing ground access according to another exemplary embodiment of the invention in which the dump frame actuator is located within the width of the chassis, but the slide frame actuators are located outside the width of the chassis; 
         FIG. 34  illustrates transverse cross-sectional shapes that can be used for the dump frame longitudinal members and slide frame longitudinal members in another embodiment of an apparatus for dumping and providing ground access; 
         FIG. 35  illustrates transverse cross-sectional shapes that can be used for the dump frame longitudinal members and slide frame longitudinal members in another embodiment of an apparatus for dumping and providing ground access; 
         FIG. 36  is a perspective view of a truck having an apparatus for dumping and providing ground access according to another embodiment of the invention, and illustrating the apparatus in an intermediate load/dump position; and 
         FIG. 37  is a front view of the truck shown in  FIG. 36  with the cab removed for clarity. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following description of various embodiments is merely exemplary in nature and is in no way intended to limit the invention, its applications, or uses. 
       FIGS. 1 through 10  illustrate one embodiment of an apparatus  100  that can be used with a vehicle  102  for dumping and providing ground access. While the illustrated embodiments depict the apparatus  100  being used with a pickup truck, aspects of the invention are not so limited. The design of the apparatus  100  is efficient enough (e.g., compact, relatively light weight, etc.) to be used on a vehicle as small as a pickup truck, but embodiments could also be relatively easily adapted to fit a larger truck or trailer. Indeed, aspects of the present invention can be applied to a wide range of vehicles, including pickup trucks, other larger commercial-type trucks, trailers, and other vehicles having a chassis to which can be attached load-carrying apparatus (e.g., load-carrying platforms and beds, etc.). Accordingly, the specific references to trucks herein should not be construed as limiting the scope of the present invention to any specific form/type of vehicle. 
     With continued reference to  FIGS. 1 through 10 , the apparatus  100  includes a dump frame  104  pivotably coupled to the truck&#39;s chassis  106 . As shown by comparing  FIGS. 3 and 4 , the dump frame  104  is pivotal relative to the chassis  106 . The apparatus  100  also includes a slide frame  108  slidably coupled to the dump frame  104 . As shown by comparing  FIGS. 3 and 6 , the slide frame  108  is longitudinally slidable relative to the dump frame  104 . The slide frame  108  pivots along with the dump frame  104  relative to the chassis  106 , as shown in  FIG. 4 . 
     With further reference to  FIG. 9 , the dump frame  104  is generally rectangular in shape. The dump frame  104  includes a pair of longitudinal members  110 , a front cross member  112 , and an intermediate cross member  114 . Each longitudinal member  110  has a front end portion  116  adjacent the truck&#39;s cab  118 , and a rear end portion  120  disposed aft of the truck&#39;s rear wheels  122 , spare tire  124 , and mud flaps  126 . The front cross member  112  extends transversely between the front end portions  116 . The intermediate cross member  114  also extends transversely between the longitudinal members  110  but at a position aft of the front cross member  112 . Having the front cross member  112  disposed between the front end portions  116  enhances rigidity of the dump frame  104 . This can be advantageous, for example, when the force for causing pivotal movement of the dump frame  104  is applied at a single location. In other embodiments, the front cross member  112  is not necessarily required and can be eliminated, for example, when the load for causing pivotal movement of the dump frame is more evenly distributed along a width defined between the longitudinal dump frame members  110 . 
     As shown in  FIGS. 1 through 4 , the apparatus  100  further includes at least one dump frame actuator  128  for causing pivotal movement of the dump frame  104  relative to the chassis  106 . In the illustrated embodiment, the dump frame actuator  128  includes a telescoping hydraulic cylinder. In other embodiments, however, the dump frame actuator  128  can be a pneumatic actuator, an electrically-operated actuator, non-cylindrical actuators, among other suitable actuation devices. For example, and as described below,  FIGS. 25 through 30  illustrate another embodiment of an apparatus  300  in which the actuation power for causing the pivotal movement is provided by a dump frame actuator  328  coupled to a linkage  394  also commonly referred to as a scissors. The combination of a dump frame actuator and scissors is commonly referred to as a scissors hoist. In the illustrated embodiment, the dump frame actuator  328  is directly connected to the scissors  394 . Alternatively, other embodiments include a dump frame actuator that is not directly connected to the scissors. In such alternative embodiments, the dump frame actuator is instead connected to the dump frame at one location, with the scissors being connected to the dump frame at a different location than the dump frame actuator. 
     While only one dump frame actuator  128  is shown in the  FIGS. 1 through 4 , alternative embodiments include a plurality of dump frame actuators that cooperate to provide the actuation power for pivotably moving the dump frame relative to the chassis. In addition, the hoses for connecting the dump frame actuator  128  to its power source have been removed for clarity. 
     In various embodiments, the dump frame actuator  128  receives power from a hydraulic pump mounted on the vehicle&#39;s engine. In another embodiment, the dump frame actuator  128  receives its power from a self-contained standalone electrically driven hydraulic power unit, which may, for example, be contained within the space (generally indicated by arrow  129  in  FIG. 1 ) defined by the vehicle&#39;s chassis  106  or at other suitable locations. Alternatively, other suitable means can be employed for providing power to the dump frame actuator  128 . For example, the dump frame actuator  128  may receive hydraulic power generated by a hydraulic pump driven off of the truck&#39;s transmission. Or, for example, a wide range of non-hydraulic power sources (e.g., electric motors in combination with gear drives, screw drives, cables and pulleys, chains and sprockets, etc.) may be used for causing the dumping pivotal movement. 
     As shown in  FIGS. 2 and 3 , the dump frame actuator  128  is a hydraulic cylinder with a first end  130  pivotably mounted to a bracket  132  of a cross member of the truck chassis  106 . In various embodiments, the apparatus  100  may be retrofit onto an existing vehicle in which case the bracket  132  may be an integral part of an replacement cross member that is coupled to the vehicle chassis after removing an existing cross member. 
     The dump frame actuator  128  also includes a second end  134  pivotably mounted to the cross member  114  of the dump frame  104 . In the illustrated embodiment, the first end  130  generally refers to the base end of the hydraulic cylinder  128 . The second end  134  generally refers to the end of the shaft or rod, which, in turn, is engaged with a piston (not shown) within the hydraulic cylinder  128 . In other embodiments, however, the first and second ends  130  and  134  may be reversed such that the base end of the actuator cylinder is pivotably mounted to the cross member  114 , and the rod end is pivotably mounted to the truck chassis  106 . Alternatively, other types of actuators (e.g., non-hydraulic actuators, pneumatic actuators, electrical actuators, non-cylindrical actuators, telescoping actuators, etc.) can also be employed with their first and second ends respectively coupled to the cross member  114  and the chassis  106 , or vice versa. 
     During operation, the dump frame actuator  128  provides the actuation power for causing pivotal movement of the dump frame  104  relative to the chassis  106 , or more specifically, about pivots  136 . In the illustrated embodiment of  FIG. 4 , each pivot  136  includes a hinge mounted to one of the longitudinal members  110  and a rear end portion of the truck chassis  106 . 
     The pivotal movement of the dump frame  104  creates an angle A ( FIG. 5 ) defined generally between the dump frame  104  and the chassis  106 . In various embodiments, the apparatus  100  is configured to be pivotable to an angle A that exceeds ninety degrees from the transport position (the transport position is shown in  FIG. 3 ). Generally, the angle A should be at least about thirty-five degrees to be considered a sufficient angle for dumping operations. 
     The dump frame  104  and dump frame actuator  128  are located within the width of the chassis  106 . Alternatively, however, either or both of the dump frame  104  and/or dump frame actuator  128  can be located outside the width of the chassis  106 . 
     As shown in  FIG. 21 , the second end  134  of the dump frame actuator  128  is vertically disposed at least partially within the height defined between the dump frame&#39;s top and bottom surfaces  138  and  140 . This helps keep the apparatus  100  relatively compact with a relatively low profile. 
     As best shown in  FIG. 9 , the cross member  114  is closer to the front end portions  116  of the longitudinal members  110  than the rear end portions  120 . Having the middle cross member  114  (to which the dump frame actuator  128  applies the pivoting force) closer to the front of the dump frame  104  advantageously creates a longer moment arm relative to the pivots  136 , thereby allowing the apparatus  100  to be pivoted with less applied force. But this more forward positioning of the middle cross member  114  also reduces the available space for the dump frame actuator  128  and increases its required stroke length. Accordingly, the inventor hereof has recognized that positioning of the middle cross member  112  involves a tradeoff between actuator size/stroke length and the moment arm length. In the illustrated embodiment, the reduced available space/stroke length for the actuator  128  resulting from the more forward positioning of the middle cross member  114  is mitigated (at least in part) by positioning the dump frame actuator&#39;s first end  130  adjacent the cab  118 . 
     Alternatively, the cross member  114  can be more centrally located relative to the dump frame  104 . Or, for example, the cross member  114  can be located closer to the rear end portions  120  than the front end portions  116  of the dump frame longitudinal members  110 . In yet other embodiments, the dump frame  104  can include more than one cross member between the front and rear end portions  116  and  120 . 
     With further reference to  FIGS. 9 and 10 , the slide frame  108  has a generally rectangular shape. The slide frame  108  includes a pair of longitudinal members or slide rails  142  disposed at least partially outside the dump frame  104 . As shown in  FIG. 22 , each longitudinal member  142  includes a generally U-shaped or C-shaped channel  144  with sliding surfaces  143 . Alternatively, other embodiments include a slide frame having differently configured longitudinal members that define channels other than U-shaped or C-shaped. In the illustrated embodiment, the slide rails  142  are made from steel I-beams. Alternative embodiments, however, include slide rails made from other suitable materials (e.g., aluminum, stainless steel, etc.) and shapes such as C-channels, among other suitable configurations including custom fabricated shapes. 
     Each engagement portion  146  has a generally rectangular shape with a side  148  attached to the corresponding longitudinal member  110  of the dump frame  104 . Each engagement portion  146  also includes three other sides or surfaces  150  that are received within the channel  144 . Alternatively, the engagement portions  146  can be configured in other suitable shapes depending, for example, on the particular application. 
     In the particular illustrated embodiment of  FIG. 22 , bearing material  152  is removably attached to the dump frame surfaces  150  to provide sliding surfaces  153  that mate with the sliding surfaces  143  of the longitudinal members  142 . The bearing material  152  is configured to make contact with the sliding surfaces  143  along substantially the entire length of the sliding surfaces  143  to inhibit foreign objects and debris from contacting the sliding surfaces  143  and  153 . Applied in this manner, the bearing material  152  provides a replaceable wear pad that substantially seals the sliding surfaces  143  and  153  of the apparatus  100 . For the embodiment shown in  FIG. 22 , the bearing material  152  is removably attached to the dump frame  104 . Alternative embodiments include bearing material that is removably or fixedly attached within the slide frame channel. In such embodiments, the sliding surfaces include the surface(s) of the bearing material and the dump frame that slidably contact one another as the slide frame slides relative to the dump frame. 
     Additional alternative embodiments include a dump frame having a channel (e.g., U-shaped channel, C-shaped channel, among other channel shapes, etc.), and a slide frame having a generally rectangular portion (or other suitably shaped portion) that is received within the dump frame channel. Bearing material may be removably or fixedly attached within the dump frame channel, and/or bearing material removably or fixedly attached to the slide frame surfaces. Other embodiments, however, do not include bearing material within either the dump frame channel or attached to the slide frame surfaces. 
     With continued reference to  FIG. 22 , the bearing material  152  is removably attached to the dump frame  104  at surfaces  150  by screws  154 . The screws  154  are recessed into the bearing material  152  such that the screws do not contact or scrape against the sliding surfaces  143  defining the slide frame channel  144 . 
     Alternatively, a wide range of other suitable attachment means can be used for removably attaching the bearing material  152  to the dump frame  104 . For example, other embodiments include bearing material that is removably attached by adhesive, rivets, clamps, snap fit, or any other suitable means. In addition, the illustrated bearing material  152  has a two-piece construction including an upper portion and a lower portion. Alternatively, other embodiments include bearing material having a single-piece or monolithic construction (e.g., bearing material  852  in  FIG. 35 ), and/or a multi-piece construction (e.g., three-piece construction, etc). Instead of, or in addition, to the bearing material  152  removably attached to the dump frame, alternative embodiments include bearing material that is removably or fixedly attached to the slide frame. In such embodiments, this bearing material can be disposed within the channel along the slide frame surfaces defining the channel. 
     In various embodiments, the bearing material  152  is disposed along the entire longitudinal length (or at least substantially the entire longitudinal length) of the dump frame surfaces  150 . With the bearing material  152  disposed longitudinally along the sliding surface  153 , the bearing material  152  substantially seals the sliding surfaces  143  and  153  and inhibits foreign objects and debris, such as dirt, dust, grime, sand, grit, and other abrasive particles, from contacting the sliding surfaces  143  and  153 . Accordingly, the bearing material  152 , applied in this manner, can help keep the sliding surfaces  143  and  153  in a relatively clean condition. This, in turn, can advantageously provide a more aesthetically pleasing mechanism while also prolonging the useful life of the sliding surfaces  143  and  153 . In the illustrated embodiment of  FIG. 22 , the bearing material  152  has a width about equal to the width of the slide frame surfaces  143  such that the bearing material  152  entirely covers (or at least substantially entirely covers) the slide frame surfaces  143 . In other embodiments, however, the bearing material  152  can have a width less than or greater than the width of the slide frame surfaces  143  depending on the particular application. For example, another embodiment includes a generally continuous strip of bearing material that is narrower than the slide frame surface along which the bearing material is longitudinally disposed. 
     In addition to this advantageous sealing effect, the bearing material  152  also reduces the friction associated with the relative sliding movement between the dump frame  104  and the slide frame  108 . In other words, there is less friction as the sliding surfaces  143  of the slide frame channel  144  slide relative to the sliding surfaces  153  of the bearing material  152  as compared to those embodiments in which there is no bearing material such that the dump frame directly contacts the slide frame as the slide frame slides relative to the dump frame. 
     By having bearing material  152  disposed along the entire length (or at least substantially the entire length) of the dump frame surfaces  150 , the load is better distributed along the entire length of the bearing material  152  such that a lubricant (e.g., grease, etc.) may not be necessary. And, without such grease or other lubricant, the apparatus  100  can remain a lot cleaner because there will be no grease or other lubricant to which dust and other particulates can adhere and accumulate. This, in turn, can prolong the useful life of the sliding surfaces  143  and  153 . Also, should any dirt or other particulates make contact with the sliding surfaces  143  and  153 , because there is no grease present, the dirt can be easily washed or blown away after extending the slide frame  108  to expose the sliding surfaces  143  and/or  153 . 
     These particular aspects of the invention relating to bearing materials and full-length replaceable wear pads (as can all other aspects of the invention) can be used individually or in combination with any one or more of the other aspects (e.g., dump frame, slide frame, interchangeable attachments, sealing members, etc.) of the present invention. 
     In some embodiments, a lubricant can nevertheless be applied to the sliding surfaces  143  of the slide frame  104  and/or to the sliding surfaces  153  of the bearing material  152  to reduce friction and facilitate sliding of the bearing material&#39;s sliding surfaces  153  within the channels  144 . For example, in embodiments that do not include bearing material or that include bearing material that is not disposed along substantially the entire length of the sliding surface, a lubricant may be at least partially disposed on at least one sliding surface to improve the sliding movement of the slide frame relative to the dump frame. But, in other embodiments, lubricant may not be needed given the friction-reducing effects of the bearing material  152 . 
     The bearing material  152  can be a wide range of suitable materials, such as various plastics. In one embodiment, the bearing material  152  comprises an ultra-high molecular weight (UHMW) polyethylene material that is relatively long-wearing and inexpensive. Alternatively, other suitable bearing materials include polymers such as polytetrafluoroethylene (PTFE), nylon and acetal, metals such as bronze, and composite materials that may include graphite. 
     In addition (or as an alternative) to bearing material, various embodiments include a seal that substantially covers and seals an interface between sliding surfaces and/or between the dump frame and the slide frame. In this exemplary manner, the seal helps prevent foreign objects and debris from entering the interface and contacting the sliding surfaces. For example,  FIG. 31  illustrates an embodiment that includes both bearing material  452  and seal  456 . In this particular illustrated embodiment, the seal  456  is a resilient member that is external to the channel  444 . Alternatively, the seal  456  can be made from non-resilient materials, such as sheet metal. In addition, various means can be employed to hold the seal  456  in place. By way of example, the seal  456  can be fastened to the slide frame member  442  using screws, adhesives, etc. 
     As shown in  FIG. 31 , the resilient member extends outwardly from the slide frame member  442  and at least partially across the top surface  438  of the dump frame longitudinal member  410 . Accordingly, the resilient member substantially seals a top portion of an interface between the dump frame member  410  and slide frame member  442 . Additionally, or alternatively, a resilient member can extend generally outwardly from the slide frame member and at least partially under the bottom surface of the dump frame longitudinal member, thereby substantially sealing a bottom portion of an interface between the dump and slide frames. In these embodiments, the bearing material  452  and seal  456  cooperate to provide an effective seal that inhibits foreign objects and debris from contacting the sliding surfaces  443  and  453 . Other embodiments, however, do not include bearing material, in which case, the seal  456  can still provide a sufficient seal for inhibiting foreign objects and debris from entering an interface and contacting the sliding surfaces. 
     As another example,  FIG. 32  illustrates an embodiment in which a seal  556  is at least partially formed by a portion  558  of the slide frame longitudinal member  542 . As shown in  FIG. 32 , the portion  558  extends over at least a portion of the top surface  538  of the dump frame longitudinal member  510 , thereby substantially sealing a top portion of an interface between the dump frame longitudinal member  510  and the slide frame longitudinal member  542 . Additionally, or alternatively, a seal can also be at least partially formed by a portion of the slide frame longitudinal member  542  that extends under at least a portion of the bottom surface of the dump frame longitudinal member  510 , thereby substantially sealing a bottom portion of an interface between the members  510  and  542 . In these embodiments, the bearing material  552  and the slide frame longitudinal member  542  cooperate to provide an effective seal that inhibits foreign objects and debris from contacting the sliding surfaces  543  and  553 . Other embodiments, however, do not include bearing material, in which case, the slide frame longitudinal member  542  can still provide a sufficient seal for inhibiting foreign objects and debris from contacting the sliding surfaces. 
     Referring back to  FIGS. 1 through 10 , the apparatus  100  further includes at least one slide frame actuator for causing sliding movement of the slide frame  108 . In the illustrated embodiment, the at least one slide frame actuator comprises two hydraulic actuator cylinders  160 . In other embodiments, however, the slide frame actuators can be pneumatic actuators, electrically-operated actuators, telescoping actuators, non-cylindrical actuators, etc. 
     While two slide frame actuators  160  are shown in the figures, any suitable number of (i.e., one or more) slide frame actuators can be used for providing the actuation power for causing sliding movement of the slide frame depending, for example, on the particular application. In addition, the hoses for connecting the slide frame actuators  160  to their power source have been removed for clarity. 
     In various embodiments, the slide frame actuators  160  receive power from a hydraulic pump mounted on the vehicle&#39;s engine. In another embodiment, the slide frame actuators  160  receive power from a self-contained standalone electrically driven hydraulic power unit, which may, for example, be contained within the space (generally indicated by arrow  129  in  FIG. 1 ) defined by the vehicle&#39;s chassis  106  or at other suitable locations. Alternatively, other suitable means can be employed for providing power to the slide frame actuators  160 . For example, the slide frame actuators may receive hydraulic power generated by a hydraulic pump driven off of the truck&#39;s transmission. Or, for example, a wide range of non-hydraulic power sources (e.g., electric motors in combination with gear drives, screw drives, cables and pulleys, chains and sprockets, etc.) may be used for causing the sliding movement. In addition, each slide frame actuator  160  does not need to receive its power from the same source as the other slide frame actuator and/or as the dump frame actuator  128 . 
     As shown in  FIG. 9 , each slide frame actuator  160  is a hydraulic cylinder with a first end  162  connected to one of the dump frame longitudinal members  110 , and a second end  164  connected to a cross member  166  of the slide frame  108 . In the illustrated embodiment, the first end  162  generally refers to the base end of the corresponding hydraulic cylinder  160 . The second end  164  generally refers to the end of the shaft or rod, which, in turn, is engaged with a piston (not shown) within the corresponding hydraulic cylinder  160 . In other embodiments, however, the orientation of either or both of the slide frame actuators  160  may be reversed with the base end(s) pivotably mounted to the cross member  166 , and the rod end(s) pivotably mounted to the dump frame longitudinal member(s)  110 . Alternatively, other types of actuators (e.g., non-hydraulic actuators, pneumatic actuators, electrical actuators, non-cylindrical actuators, telescoping actuators, etc.) can also be employed with their first and second ends respectively coupled to the cross member  166  and dump frame longitudinal members  110 , or vice versa. 
     Each slide frame actuator  160  is disposed along a substantial length of the dump frame longitudinal members  110 , which allows the slide frame actuators  160  to have a relatively large stroke length. In addition, having the slide frame actuators  160  disposed on opposite sides of the slide frame  108  imparts a more well-balanced sliding movement to the slide frame  108 . 
     Each slide frame actuator  160  is mounted to the dump frame  104  through a coupling member  168 . Each coupling member  168  extends inwardly and transversely from a respective one of the longitudinal members  110 . The coupling members  168  are longitudinally disposed between the front end portions  116  of the longitudinal members  110  and the middle cross member  114 . 
     As shown in  FIGS. 2 and 21 , each slide frame actuator  160  extends rearwardly from the coupling member  168 , through an opening  170  ( FIG. 21 ) in the middle cross member  114  of the dump frame  104 , and to the rear cross member  166  of the slide frame  108 . In the illustrated embodiment, the openings  170  are generally rectangular through-holes defined by the cross member  114 . Alternatively, however, other suitably configured openings beside rectangular through-holes may be employed including circular through-holes, other non-rectangular through-holes, notches, cutouts, etc. 
     When the slide frame actuators  160  are actuated, the slide frame actuators  160  push against the slide frame&#39;s rear cross member  166  with sufficient force to cause the slide frame  108  to slide on the dump frame  104  rearwardly away from the truck&#39;s cab  118 , as shown by comparing  FIG. 9  with  FIG. 10 . 
     The slide frame actuators  160  are located within the width of the chassis  106  and within the width of the dump frame  104 . Alternative embodiments, however, include the slide frame actuators being located outside the width of the chassis. For example,  FIG. 33  illustrates an alternative embodiment  600  in which the dump frame actuator  628  is located within the width of the vehicle chassis, but the slide frame actuators  660  are located outside the width of the vehicle chassis. Each slide frame actuator  660  has a first end  662  connected to one of the dump frame longitudinal members  610 , and a second end  664  connected to one of the slide frame longitudinal members  642 . Each slide frame actuator  660  is disposed along a substantial length of the dump frame longitudinal members  610 . But in this particular embodiment, the slide frame actuators  660  are located outside the dump frame longitudinal members  610 . 
     Referring to  FIGS. 21 and 22 , the slide frame longitudinal members  142  include a top surface  172  and a bottom surface  174  which define a height therebetween. The first and second ends  162  and  164  of each slide frame actuator  160  are vertically disposed at least partially within the height defined between the slide frame&#39;s top and bottom surfaces  172  and  174 . The slide frame actuators  160  are also vertically disposed at least partially within the height defined between the dump frame&#39;s top and bottom surfaces  138  and  140 . With this arrangement, the slide frame actuators  160  do not add (or add very little) to the overall height of the apparatus  100 . Accordingly, this arrangement helps provide the apparatus  100  with a relatively compact and low profile structure. 
     Moreover, and as shown in  FIG. 22 , the second end  134  of the dump frame actuator  128  is also vertically disposed within the height defined between the slide frame&#39;s top and bottom surfaces  172  and  174 . In addition, the dump frame actuator  128  and the slide frame actuators  160  are at least partially located in a plane that is substantially parallel to the slide plane of the slide frame  108 . At least a portion of the dump frame actuator  128  and at least a portion of each slide frame actuator  160  are located in the same plane, which, in turn, is substantially parallel to a plane through which at least a portion of the slide frame  108  slides. Accordingly, the dump frame actuator  128  also does not add (or adds very little) to the overall height of the apparatus  100 , thus helping to keep the size of the apparatus  100  relatively compact and low profile. 
     As shown in  FIG. 1 , the chassis  106  can also include a filler strip  176  for providing a substantially flat surface for supporting the slide frame  108 . The filler strip  176  further provides a flush appearance that adds to the aesthetic appearance of the truck  102 . Depending on the particular material from which the filler strip  176  is formed, the filler strip  176  can also operate as a shock absorber. In one embodiment, the filler strip  176  is formed from a hard wood such as oak. Alternatively, a wide range of other materials can be used for the filler strip  176  including various plastics, hard rubber, or composite materials. 
     With reference now to  FIGS. 11 through 20 , a load-carrying platform can be removably attached (e.g., bolted, etc.) onto the slide frame  108 . In the illustrated embodiment, the load-carrying platform comprises a bed  178  that is bolted to the upper portion of the slide frame&#39;s longitudinal members  142 . The bed  178 , however, is shown for purposes of illustration only and not for purposes of limitation as a wide range of other suitable load-carrying platforms can also be employed. In addition to load-carrying platforms, a wide range of other interchangeable attachments can also be provided each of which is removably attachable to the slide frame  108 . This can further enhance the functionality and utility of the truck  102  having the apparatus  100 . Exemplary load-carrying attachments that can be attached to the apparatus  100  include a boom, a fork lift attachment, an attachment (e.g., hook, pointed rod, etc.) for picking up hay bales, etc. 
     These particular aspects of the invention relating to interchangeable attachments (as can all other aspects of the invention) can be used individually or in combination with any one or more of the other aspects (e.g., dump frame, slide frame, sealing members, full-length replaceable wear pads, etc.) of the present invention. 
     As shown by comparing  FIG. 11  with  FIG. 14 , the bed  178  is movable along with the slide frame  108 . The bed  178  includes a tailgate  180 . The tailgate  180  when opened ( FIG. 16 ) allows easier ground access to the bed  178 . But when the tailgate  180  is closed ( FIG. 11 ), the tailgate  180  helps retain a load within the bed  178 . 
     As shown in  FIGS. 20 through 22 , the bed  178  is supported by the slide frame  108  and the chassis  106  without the dump frame  104  having to support the bed  178  or the load carried by the bed  178  when the apparatus  100  is in the transport position. A clearance or gap  182  ( FIGS. 21 and 22 ) separates the top surface  138  of the dump frame  104  from the bed cross member  184 . The bed cross member  184  is supported on the top surface  172  of the slide frame  108 , which, in turn, is supported by the chassis  106  through filler strip  176 . 
     As shown in  FIG. 23 , the bed  178  includes a winch  186  to facilitate loading and unloading of a load (e.g., cargo, goods, motorcycle, four-wheel all terrain vehicle, riding lawn mower, etc.) onto/off the bed  178 . The winch  186  is preferably attached so that it may be removed from the bed  178  when the winch  186  is not in use. As shown in  FIGS. 20 and 21 , a receiver  187  is provided at the front of the bed  178  along with an electrical power outlet for the winch  186 . The receiver  187  can be similar to the truck&#39;s tow hitch receiver  189  ( FIG. 19 ). The truck may also be similarly equipped to mount the winch  186  in a tow hitch receiver  189  at the rear and/or front of the vehicle. Also, in those embodiments in which both the slide and dump mechanisms are contained within the chassis  106 , there is provided useable space on the outside of the chassis  106  below the bed  178  for tool boxes or storage boxes, among other items. For example, one such storage box can be used for storing the winch  186  when the winch  186  is not being used. 
     In addition, the bed  178  also includes slidable portions  188  that are positioned adjacent an openable portion of a rear window of the cab  118 . The portions  188  can be opened ( FIG. 19 ) by slidably moving the portions  188  away from one another, for example, to allow a person within the cab  118  to access the bed  178  through the cab&#39;s rear window. The portions  188  can be closed ( FIG. 20 ) by slidably moving the portions  188  towards one another, for example, to help protect the cab&#39;s rear window from a load within the bed  178 . 
     The apparatus  100  can be positioned in various positions, including but not limited to a transport position ( FIG. 3 ), an intermediate dump position ( FIG. 4 ), a dump position ( FIG. 5 ), a slidably extended position ( FIG. 6 ), an intermediate load/dump position ( FIG. 7 ), and a load position ( FIG. 8 ). The apparatus  100  can also be configured for pivotal movement to dumping angles greater than what is shown in the figures depending, for example, on the particular application. In addition, the sliding movement can occur before, after, or during the pivoting movement depending on the particular operation for which the apparatus  100  is being used. 
     To allow an operator to selectively move the apparatus  100  into a particular position, a wide range of switching mechanisms may be employed. In the illustrated embodiment, a switching device  190  ( FIG. 3 ) is externally mounted to the chassis  106  on the driver side of the truck  102 . A switching device can also or instead be mounted on the passenger side of the truck  102 . In various embodiments, the external switching device does not include an on/off power switch, but instead this on/off switching is controlled by a switching device within the cab. The switching device may be electrical, hydraulic, or any other type or combination thereof depending on the type of actuators and type of power used. 
     As shown in  FIG. 3 , the switching device  190  includes three switches: a switch for switchably controlling the sliding movement, a switch for switchably controlling the pivoting movement, and a switch for switchably controlling an attachment such as the winch  186 . Alternatively, the switching device  190  can include more or less switches in any other suitable configuration. Additionally, or alternatively, a switching device may also be provided within the cab  118  to allow a person within the cab  118  to control operation of the apparatus  100 . As yet another example, the apparatus  100  can additionally or alternatively be configured such that its operation can be remotely controlled by an external transmitter or remote control device. In such embodiment, the apparatus  100  can be operatively associated with a controller capable of receiving signals from a remote control device (e.g., wireless signals communicated between antennae, electromagnetic wave energy, cellular phone, RF energy or radio transmissions, infrared, etc.). Signals received by the controller can then provide information to the controller for causing the controller to selectively operate the dump frame actuator  128  and slide frame actuators  160  in accordance with the particular selection made by the operator. 
     In various embodiments, the apparatus  100  is configured to be bolted onto the truck chassis  106 . With this bolting arrangement, embodiments of the apparatus  100  can be readily retrofit onto existing trucks of various sizes and types. 
       FIGS. 24A and 24B  illustrate another embodiment of bed  278  that can be used with an apparatus  200  of the present invention. In this particular embodiment, the bed  278  includes a support  291  on each of the passenger and driver sides of the bed  278 . These supports  291  can be extended to help support the bed  278  for removal from, and attachment to the truck  202 . As shown in  FIG. 24A , a pair of supports  292  can be positioned under a rear end portion of the bed  278 , and the supports  291  can be extended. As shown in  FIG. 24B , the bed  278  can then be detached from the slide frame  208 . At which point, the truck  202  can be driven away without the bed  278  as the bed  278  remains supported by the supports  291  and  292 . In various embodiments, the supports may include one or more wheels for rolling on the ground. In such embodiments, the wheeled supports can help support the bed, for example, to facilitate moving the bed when it is detached from the truck. In yet other embodiments, the supports may be separate components that are not fastened to the bed. As described above, a wide range of interchangeable attachments (e.g., a boom, a fork lift attachment, an attachment for picking up hay bales, etc.) can be provided each of which is removably attachable to the slide frame. Any of the attachments can also include supports that can be extended to help support the interchangeable attachment for removal from, and engagement to the truck. 
       FIGS. 25 through 30  illustrate another embodiment of an apparatus  300  in which the actuation power for causing pivotal movement is provided by a dump frame actuator  328  coupled to a linkage or scissors  394 . The combination of a dump frame actuator and scissors is commonly referred to as a scissors hoist. 
     In the illustrated embodiment, the dump frame actuator  328  is a non-telescoping hydraulic cylinder. In other embodiments, however, the dump frame actuator  328  can be a pneumatic actuator, an electrical actuator, a non-cylindrical actuator, a telescoping actuator, among other suitable actuation devices. 
     While only one dump frame actuator  328  is shown in  FIGS. 25 through 30 , alternative embodiments include a plurality of dump frame actuators that cooperate to provide the actuation power for pivotably moving the dump frame relative to the chassis. In addition, the hoses for connecting the dump frame actuator  328  to its power source have been removed for clarity. 
     In various embodiments, the dump frame actuator  328  receives power from a hydraulic pump mounted on the vehicle&#39;s engine. In another embodiment, the dump frame actuator  328  receives its power from a self-contained standalone electrically driven hydraulic power unit, which may, for example, be contained within a space (generally indicated by arrow  329  in  FIGS. 25 and 28 ) defined by the vehicle&#39;s chassis  306  or at other suitable locations. Alternatively, other suitable means can be employed for providing power to the dump frame actuator  328 . For example, the dump frame actuator  328  may receive hydraulic power generated by a hydraulic pump driven off of the truck&#39;s transmission. Or, for example, a wide range of non-hydraulic power sources (e.g., electric motors in combination with gear drives, screw drives, cables and pulleys, chains and sprockets, etc.) may be used for causing the dumping pivotal movement. 
     As shown in  FIG. 29 , the dump frame actuator  328  is a non-telescoping hydraulic cylinder with a first end  330  pivotably coupled to the truck chassis  306 , and a second end  334  pivotably coupled to a member  396  of the scissors  394 . In the illustrated embodiment, the first end  330  generally refers to the base end of the hydraulic cylinder  328 . The second end  334  generally refers to the end of the shaft or rod, which, in turn, is engaged with a piston (not shown) within the hydraulic cylinder  328 . In other embodiments, however, the first and second ends  330  and  334  may be reversed such that the base end of the actuator cylinder is pivotably coupled to the scissors, and the rod end is pivotably coupled to the vehicle chassis. Yet other embodiments include a dump frame actuator that is not directly connected to the scissors, but instead the dump frame actuator is connected to the dump frame at a different location than the location at which the scissors is connected to the dump frame. In still further embodiments, other types of actuators (e.g., non-hydraulic actuators, pneumatic actuators, electrical actuators, non-cylindrical actuators, telescoping actuators, etc.) can be employed with their first and second ends coupled to the scissors and chassis (or vice versa) or coupled to the dump frame and chassis (or vice versa). 
     With reference to  FIG. 25 , the scissors  394  includes an end portion  398  coupled to the dump frame cross member  314 . In this embodiment, the pivoting force applied to the dump frame cross member  314  is distributed at least partially along the width of the dump frame cross member  314 . This, in turn, provides well-balanced and stable pivoting movement to the apparatus  300 . In the illustrated embodiment, the dump frame  304  includes a front cross member  312  that enhances rigidity of the dump frame  304 . But the front cross member  312  is not necessary for and may be eliminated in some embodiments, such as when the load for causing pivotal movement of the dump frame is more evenly distributed or spread out relative to the longitudinal dump frame members. 
       FIGS. 34 and 35  illustrate alternative cross-sectional shapes that can be used for dump frame longitudinal members  710 ,  810  and slide frame longitudinal members  742 ,  842 . As shown in  FIG. 34 , the dump frame longitudinal member  710  is vertically disposed entirely within the height defined between the slide frame member&#39;s top and bottom surfaces  772  and  774 .  FIG. 34  does not show bearing material disposed along the sliding surfaces (which in the particular illustrated embodiment include three outer surfaces  753  of the dump frame longitudinal member  710  and the inner surfaces  743  defining the slide frame channel  744 ). Alternative embodiments, however, include bearing material disposed at least partially along one or more sliding surfaces. 
     As shown in  FIG. 35 , the dump frame longitudinal member  810  is vertically disposed entirely within the height defined between the top and bottom surfaces  872  and  874  of the slide frame longitudinal member  842 . In addition, bearing material  852  is disposed along the sliding surfaces (which in the particular illustrated embodiment include the outer surfaces  853  of the bearing material  852  and the inner surfaces  843  defining the slide frame channel  844 ). In this particular embodiment, the bearing material  852  has a single-piece or monolithic construction, although other embodiments include a bearing material having a multi-piece construction (e.g., two-piece construction, three-piece construction, etc). The bearing material  852  seals the sliding surfaces  843  and  853  and inhibits foreign objects and debris from contacting the sliding surfaces  843  and  853 . In addition, the bearing material  852  also reduces friction between the sliding surfaces  843  and  853 . 
       FIGS. 36 and 37  illustrate another embodiment of an apparatus  900  that can be used with a vehicle  902  for dumping and providing ground access. As shown, the apparatus  900  includes a dump frame  904  pivotably coupled to the truck&#39;s chassis  906 . The dump frame  904  includes a pair of longitudinal members  910 , a front cross member  912 , and an intermediate cross member  914 . 
     The apparatus  900  also includes a slide frame  908  slidably coupled to the dump frame  904 . The slide frame  908  includes a pair of longitudinal members or slide rails  942  disposed at least partially outside the dump frame  904 . 
     In this particular embodiment, the dump frame longitudinal members  910  are vertically disposed entirely within the height defined between the top and bottom surfaces  972  ( FIG. 36) and 974  ( FIG. 37 ) of the slide frame longitudinal members  942 . In addition, this particular embodiment does not include bearing material disposed along the sliding surfaces. But alternative embodiments include bearing material disposed at least partially along the sliding surfaces of the dump frame members  910 . 
     Accordingly, various embodiments provide relatively compact and low-profile mechanisms for dumping and providing ground clearance, for example, to a bed of a pickup truck. In various embodiments, the mechanism has such a low profile and is contained within the width of the truck&#39;s chassis that the mechanism is not readily apparent to a casual observer. In addition, various embodiments also include actuators that are at least partially side-by-side and not stacked on top of each other such that the resulting device is relatively low profile. Further embodiments also seal the sliding surfaces to inhibit foreign objects and debris (e.g., dirt, dust, grime, sand, grit, other abrasive particles, etc.) from contacting the sliding surfaces. In some embodiments, the seal includes bearing material that also reduces friction between the sliding surfaces without a lubricant therebetween. By sealing the sliding surfaces in this manner, the sliding surfaces can be kept in a relatively clean condition, which, in turn, can provide a more aesthetically pleasing mechanism while also prolonging the useful life of the sliding surfaces. 
     The teachings of the present invention can be applied to a wide range of vehicles, including pickup trucks, other larger commercial-type trucks, trailers, and other vehicles having a chassis to which can be attached load-carrying apparatus, such as load-carrying platforms and beds. Accordingly, the specific references to pickup trucks should not be construed as limiting the scope of the present invention to any specific form/type of vehicle. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.