Patent Document

BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to ramps for use between a pair of surfaces of different elevation to facilitate transporting cargo from one of the surfaces to the other of the surfaces, and more particularly to ramps used to load and unload cargo from a vehicle trailer. 
   2. Related Art 
   When transporting numerous and/or heavy containers, generally, a large semi trailer, or the like, is used, and commonly, ramps are use to facilitate loading and removing the containers into and from the trailer. The ramps are typically built integrally into the trailer, and are pulled out from a rear portion of the trailer for use, and pushed back into the trailer for storage. These ramps can prove difficult to use when the tracks along which they slide become corroded, and from their being generally large, heavy and cumbersome. Otherwise, when the trailer does not have a built-in ramp, commonly, portable ramps are used. The portable ramps are typically formed having a single piece load support surface extending between one end arranged for attachment to the transport vehicle, and another end arranged for abutment with a ground surface. Some of these ramps are commonly constructed with nubs extending upwardly from the support surface to facilitate maintaining traction with the load surface in use. Unfortunately, when the nubs become worn, they are unable to be replaced, and thus, the ramp can become slippery after extended use. As a result, the ramp typically must be replaced with a new ramp. 
   SUMMARY OF THE INVENTION 
   A portable ramp assembly has a pair of laterally spaced side rails and a plurality of panels adapted for releasable attachment to a separate one of the side rails to form a generally planar support surface facing upwardly, and a generally planar surface facing downwardly. The panels are individually removable from the side rails so that opposite sides of the panels can be reversed to function as the upper support surface. 
   In another aspect of the invention, a method of constructing a portable ramp begins by providing a pair of elongate side rails and a plurality of cross members having opposite ends. Then, continuing by fixing one end of each cross member to one of the side rails, and fixing the other end of each cross member to the other of the side rails so that the side rails are rigidly spaced laterally from one another. Next, the method comprises providing a plurality of panels having opposite ends and releasably attaching one of the ends to one of the side rails, and the other of the ends to the other side rail to form a generally planar support surface facing upwardly and a generally planar idle facing downwardly. 
   Some of the potential objects, features, and advantages of at least some of the presently preferred embodiments of the invention include, but are not limited to, a portable ramp assembly that has individual load support panels that are reversible to provide a fresh traction surface, allow replacement of individual panels to extend the useful life of the ramp assembly, is economical in design and manufacture, is lightweight and durable, is easy to use, is relatively compact, and provides a long useful life. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, features, and advantages of the invention will become readily apparent in view of the following detailed description of the presently preferred embodiments and best mode, appended claims and accompanying drawings, in which: 
       FIG. 1  is a side view of a portable ramp assembly according to one aspect of the invention; 
       FIG. 2  is a partially assembled perspective view of the ramp assembly of  FIG. 1  showing cross members maintaining a pair of side rails in laterally spaced relation; 
       FIG. 3  is a fully assembled perspective view of the ramp assembly of  FIG. 2 ; 
       FIG. 4  is a partial perspective view of the ramp assembly of  FIG. 3  showing a panel being releasably attached between the side rails; 
       FIG. 5  is a cross-sectional view of the ramp assembly taken generally along line  5 - 5  of  FIG. 4 ; 
       FIG. 6  is an enlarged view of the encircled area  6  of  FIG. 5 ; 
       FIG. 7  is an assembled perspective view of another presently preferred embodiment of the invention; 
       FIG. 8  is a cross-sectional view of the ramp assembly taken generally along line  8 - 8  of  FIG. 7 ; and 
       FIG. 9  is an enlarged view of the encircled area  9  of  FIG. 8 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring in more detail to the drawings,  FIG. 1  illustrates a portable ramp assembly  10  in a secured position between a vehicle trailer  12  and a ground surface  14  to facilitate loading and unloading cargo  16  into and from the trailer, such as with the use of a hand truck  18 , readily available from Magline, Inc., of Pinconning, Mich. As shown in  FIG. 3 , the ramp assembly  10  has a plurality of panels  20  extending between opposite side rails  22 ,  23  to provide a generally planar, upwardly facing support surface  24  to facilitate transporting the cargo  16  into and out of the trailer  12 . The panels  20  are reversible in end-over-end fashion and interchangeable or individually replaceable to allow worn or damaged sections of the support surface  24  to be replaced in position to extend the useful life of the ramp assembly  10 . 
   The side rails  22 ,  23  are constructed from a rigid, high strength material, and are preferably formed from a high strength polymeric or metallic material, and more preferably are extruded from aluminum. As shown in  FIGS. 2-4 , the side rails  22 ,  23  are preferably formed as generally flat beams with opposite inner and outer sides  26 ,  27 . The outer sides  27  preferably have a recessed channel  28  to facilitate weight reduction, and the inner sides  26  preferably have a panel supporting flange  30  ( FIGS. 2 ,  5  and  6 ) extending laterally outwardly therefrom generally along the length of the side rails  22 ,  23 . The flanges  30  are preferably formed as one piece with the side rails  22 ,  23 , though they could be constructed separately from the side rails  22 ,  23 , and thereafter, attached thereto, such as through a weld joint or fasteners, for example. The flanges  30  have a plurality of openings  32  ( FIG. 2 ) spaced a predetermined distance from one another to facilitate attachment of the panels  20  to the side rails  22 ,  23 . The side rails  22 ,  23  preferably have one end  34  with a convergent configuration, and shown here by way of example, as having converging opposite edges  36  to form a triangular nose portion  38  facilitating making a flat engagement between the nose portion  38  and the ground surface  14 . 
   As shown in  FIGS. 2 and 3 , a relatively rigid ladder-like frame  38  is constructed by maintaining the side rails  22 ,  23  laterally spaced from one another by a plurality of cross members  40 . The cross members  40  are preferably equal in length and fixed between the cross rails  22 ,  23 , such as, by way of example and without limitations, through a weld joint or fasteners to maintain the cross rails  40  in a fixed, generally parallel relation to one another. The cross members  40  are preferably spaced equidistant from one another along the length of the side rails  22 ,  23  to define panel receiving openings or spaces  42  of equal size between the cross members  40  to receive a predetermined number of panels, and represented here, by way of example and without limitations, as a pair of panels  20  within each space  42 . As best shown in  FIG. 5 , to facilitate receiving and maintaining the drop-in panels  20  within the spaces  42 , the cross members  40  preferably have leading edges with an outwardly extending protrusion or tongue  44 , and trailing edges with an flange or stop surface  46  extending outwardly and generally perpendicularly from the trailing edge, such that the stop surface  46  is generally laterally offset and parallel to the support surface  24 . The cross members  40  are preferably constructed having a hollowed core  48 , and are preferably extruded from aluminum. It should be recognized that the cross members  40  can be solid, and constructed using other rigid, high strength materials, such as high strength polymeric or fiber reinforced materials, for example, and that other manufacturing methods, i.e. molding, stamping and bending, could be used. 
   The ladder-like assembly  10  has a lower end cross member  50  with upper and lower surfaces  51  extending divergently so as to be generally triangular in cross section and conforming to the shape of the triangular nose portions  37  of the side rails  22 ,  23 . As shown in  FIG. 5 , the lower end cross member  50  is preferably constructed from extruded aluminum stock, and preferably has ribs  51  a forming a receptacle  52  traversing a back side to facilitate assembly of the panels  20  within the opening  42  between the lower end cross member  50  and the next closest cross member  40 . 
   The panels  20  may be die-cast from magnesium or aluminum, though other materials and processes, such as steel or high strength polymeric material and molding or extruding could be used to construct the panels. The panels  20  have opposite upper and lower grid sides  54 ,  55  preferably having an identical tread configuration extending between opposite ends  56 ,  57  defining opposite leading and trailing edges  58 ,  59 . The opposite sides  54 ,  55  preferably have raised, outwardly extending protrusions or nubs  60  over their upper and lower surfaces to facilitate maintaining traction. In addition to, or in lieu of the nubs  60 , the sides  54 ,  55  may have recessed or scalloped areas, thereby rendering the planar surface as the traction surface. As best shown in  FIG. 4 , to further increase the traction, promote drainage and reduce the weight of the assembly, the panels  20  preferably have a plurality of through openings  62 . The through openings  62  are bounded by web portions  64  arranged in a honeycomb or grid configuration. 
   As shown in  FIGS. 4-6 , the leading edges  58  of the panels  20  are preferably formed having an outwardly extending tongue or protrusion  66  for positive supporting engagement with the flange or lip stop surfaces  46  of the cross members  40 , and for interlocking receipt in the trailing socket or groove edge  59  of the adjacent panel  20 . The protrusions  66  may extend intermittently or substantially across the leading edge  58 . The trailing edges  59  of the panels  20  are formed with a lateral recess or channel  68  sized for receipt of the leading tongue edges  44  of the cross members  40  and the tongue  66  of an adjacent panel  20 . The leading and trailing edges define a width of the panels, wherein the width is preferably defined so that a pair of panels  20  are received within each of the spaces  42  between a pair of the cross members  40 . The opposite ends  56 ,  57  of the panels  20  define a length of the panels  20  which is such that the panels  20  preferably fit between the side rails  22 ,  23 , but overlie the opposite flanges  30  on the side rails  22 ,  23 . The panels  20  have fastener openings  70  ( FIG. 3 ) adapted to align with the openings  32  in the flanges  30  and/or cross members  40  to facilitate attachment of the panels  20  to the side rails  22 ,  23  and/or cross members  40 . Each panel  20  is shown here, by way of example, as being attached to the side rails  22 ,  23  via a pair of fasteners  72  ( FIG. 4 ), such as standard bolts, adjacent the opposite ends  56 ,  57  of the respective panel  20 , though more fasteners could be used in combination with more through openings in the side rails, if desired. 
   In assembly, the panels  20  are individually attached to the frame  38  via the fasteners  72 . Within each space  42 , a pair of panels  20  is disposed such that the channel  68  of a first panel  20  is disposed to receive the tongue  44  of one cross member  40 , while the protrusion  66  on the opposite end of the first panel  20  is disposed within a channel  68  of a second adjacent panel  20 . The protrusion  66  of the second panel  20  is then lowered for supporting engagement with the stop surface  46  of another cross member  40 . This process is continued until all the panels  20  are attached to the frame  38 . In the space  42  between the lower cross member  50  and the next closest cross member  40  ( FIG. 5 ), the protrusion  66  of a first panel  20  is disposed in the receptacle  52  of the lower cross member  50 , and the channel  68  of a second panel  20  receives the protrusion  66  of the cross member  40 . Thereafter, the protrusion  66  of the second panel  20  is guided for receipt within the channel  68  of the first panel  20  as the first and second panels  20  are lowered into engagement with the flanges  30  of the side rails  22 ,  23 . Thereafter, the fasteners  72  are inserted through the fastener openings  70  and into the openings  32  in the flanges  30  to secure the panels  20  in their releasably attached positions with conventional nuts. With the adjacent panels  20  being interlocked with one another, and with the panels  20  engaging respective ones of the cross members  40 , any load applied to an individual panel  20  is uniformly distributed among the interlocked panels  20 , and the cross members  40 . As such, the individual panels  20  may be constructed having further reduced material content, as the entire applied load is not being borne by any single panel  20  at one time. Additionally, as one of the sides  54 ,  55  of the separate panels  20  becomes worn, damaged, or otherwise rendered undesirable for continued use, the respective panel  20  may be removed from the frame  38  by removing the associated fasteners  72 , and then the panel  20  can be flipped end-over-end to bring the unused or fresh side  54 ,  55  from its idle position to the support position. 
   As shown in  FIG. 7 , a ramp assembly  110  is constructed according to another presently preferred embodiment of the invention. The ramp assembly has a pair of side rails  122 ,  123  constructed generally the same as in the previous embodiment. The side rails  122 ,  123  have flanges  130  ( FIGS. 8 and 9 ), on which cross members  140  are fixed or attached, such as through a weld joint or fasteners, for example. The flanges  130  have openings (not shown) spaced therealong at predetermined locations to facilitate attaching a plurality of panels  120  between the side rails  122 ,  123 . The cross members  140  have opposite sides  141  extending between the side rails  122 ,  123  constructed for mating cooperation with the panels  120 , and are shown here, by way of example and without limitations, as having recessed channels  143  therein. The channels  143  are sized for receipt of protrusions  166  extending from the sides of the panels  120  to interlock the panels  120  and cross members  140 . As such, loads applied to the panels are distributed uniformly to the cross members  140 . 
   As shown in  FIGS. 7 and 8 , by way of example and without limitation, three grid panels  120  are received within spaces  142  between adjacent cross members  140 . The outer panels  120  adjacent the cross members  140  have one of the protrusions  166  inserted into the channels  143  in the cross members  140 . The middle panel  120  is set between the outer panels  120 , with the protrusions  166  of the middle panel  120  and the adjacent outer panels  120  being slightly spaced from one another to accommodate clamp assemblies  145 . The panels  120  are preferably fastened to the flanges  130  of the side rails  122 ,  123  via fasteners, as in the previous embodiment. 
   As shown in  FIG. 9 , the clamp assemblies  145  have opposite elongate upper and lower plates  147 ,  149  arranged for attachment to one another and preferably to the flanges  130  of the side rails  122 ,  123  to facilitate maintaining the panels  120  in a releasably fixed position relative to the side rails  122 ,  123 . The plates  147 ,  149  are arranged in overlying relation to portions of opposite sides of the adjacent panels  120  and are drawn toward one another to clamp on the portions of the panels  120  upon being attached to one another. As such, at least a portion of the adjacent panels  120  are received between the opposite upper and lower plates  147 ,  149 . The plates  147 ,  149  are preferably extruded or molded from aluminum, though they could be formed from any suitable high strength resilient material, including high strength plastics, for example. The plates  147 ,  149  preferably have inwardly extending curled edges  151  that overlie the protrusions  166 , preferably in a mating and generally conforming relation, and capture or clamp about the protrusions  166  extending from the edges of the adjacent panels  120 . The plates  147 ,  149  are represented here, by way of example and without limitations, as being attached to one another via bolts  153  passing through axially aligned openings in the plates  147 ,  149 , with standard nuts  155  being threaded onto the ends of the bolts  153 . The upper plates  147  preferably have a counter bore or recessed channel  157  sized to receive the enlarged heads of the bolts  153  such that the bolts  153  remain generally flush or slightly recessed relative to the traction surface of the panels  120 . When a panel or panels  120  become worn on one side, the respective nuts  155  and bolts  153  may be easily removed and the worn panels  120  may be flipped to bring a fresh side upward. The panels  120  are then reattached between the side rails  122 ,  123 , at least in part, via the bolts  153  and nuts  155 . 
   It should be recognized that upon reading the disclosure herein, that one ordinarily skilled in the art of would readily recognize other embodiments than those disclosed herein, with those embodiments being within the spirit and scope of the invention. Accordingly, the disclosure herein is intended to be exemplary, and not limiting. The scope of the invention is defined by the following claims.

Technology Category: 7