Abstract:
A portable ramp for providing a bridge between surfaces of different elevations. The ramp includes a unitary construction which includes a traction plate, foot section and tongue section. The foot section has one or more serrations along a curved surface. The tongue section includes a binder for increased friction at the elevated surface. A safety line and hand hold are also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to a portable ramp for providing a bridge between surfaces of different elevations such as a ground level surface and a raised surface. Devices of this basic type have been commonly used for transport of heavy or wheeled objects from one level to another. One such device is disclosed in the patent granted to Edward Smith (U.S. Pat. No. 4,853,999). Here a ramp having a plurality of plates is disclosed. A lower plate section contacts the ground on one end and is jointedly connected to an upper plate section. A separate support rail extends between the plate sections. Other devices, such as the wagon-skid of U.S. Pat. No. 1,261,967, contemplate the addition of conveyor means to the ramp. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved utility ramp which is portable, lightweight, and more importantly, provides a unitary construction which is durable and reliable. The present invention further provides an improved foot portion which engages the ground surface with serrations on a curved surface. This improved foot portion grippingly engages the ground over a wide range of raised heights, thus increasing the usefulness of a ramp of this type. 
     Further, the present ramp includes a tongue portion or receptacle which is adapted to be received and engaged by the raised surface. The traction plate includes oppositely disposed, downwardly formed, substantially coextensive apron portions. Each of these apron portions further defines a substantially coextensive, generally U-shaped channel. The U-shaped channel is formed by a base portion having a pair of bifurcated leg portions extending therefrom. Each of the bifurcated legs further includes an arcuate portion whereupon a plurality of serrations is formed. 
     As discussed above, the serrations engage the ground surface at any point in the arcuate surface touching the ground. In this manner the serrations engage the ground at any of a variety of heights. That is, as the height between the ground surface and the raised surface increases, the arcuate portion rotates to maximize the area engaging the ground surface. 
     It is an object of the present invention to provide a utility ramp having unitary construction of the receptacle, plate and foot members. It is a further object to provide a ramp that has a foot member capable of gripingly engaging the ground level surface at substantially any angle relative to the raised surface. It is an object of the present invention to provide a ramp having a tongue section or receptacle capable of frictionally engaging with the raised surface. It is yet a further object to provide a utility ramp that is facilely connected to and disconnected from the raised surface. These and other objects will be apparent in the descriptions that follow. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of one embodiment of the utility ramp of the present invention and showing a straight traction plate. 
     FIG. 2 is a perspective view of the embodiment illustrated in FIG. 1, but shown in conjunction with a pickup truck, seen in phantom. 
     FIG. 3 is a perspective view of an alternate embodiment of the utility ramp of the present invention and showing a curved traction plate. 
     FIG. 4 is a perspective view of the embodiment illustrated in FIG. 3, but shown in conjunction with a pickup truck, seen in phantom. 
     FIG. 5 is a fragmentary view showing the underside of the foot end of the utility ramp. 
     FIG. 5 a  is a fragmentary view showing the underside of an alternative foot end of the utility ramp. 
     FIG. 6 is a fragmentary perspective view of the tongue portion of the present invention and showing the protective binder attached to the marginal edge thereof. 
     FIG. 7 is a fragmentary side plan view of the tongue portion of the present invention. 
     FIG. 8 is a fragmentary perspective view of the tongue portion of the present invention and showing an alternate embodiment protective binder on a portion thereof. 
     FIG. 8 a  is a cross sectional view, taken along lines  8   a — 8   a  of FIG.  8 . 
     FIG. 9 is a cross sectional view of the ramp shown in FIG.  8  and taken along lines  9 — 9  thereof. 
    
    
     DETAILED DESCRIPTION 
     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
     As seen in FIG. 1, the utility ramp of the present invention is indicated generally by the reference numeral  10 . The ramp  10  may be substantially planar as seen in FIGS. 1 and 2, or, in an alternate embodiment, the ramp  10  may be provided with a generally convex curve along its length, as seen in FIGS. 3 and 4. The embodiment of FIGS. 3 and 4 is especially useful in the event that the object to be elevated is especially low riding, as in the case of a lawn tractor with mowing deck (not shown). The ramp is preferably constructed of a rigid metal such as aluminum, although any other material of sufficient strength may be used. The ramp  10  comprises a unitary traction plate  12  having a first end  14  and a second end  16 . The first end  14  includes an integrally formed tongue section  18  adapted for securement to an elevated surface, shown in FIGS. 2 and 4 in phantom as a truck bed  11 . The second end  16  of the ramp  10  is provided with an integrally formed foot portion  20 . Foot portion  20  is adapted to engagingly support the traction plate  12  at a level lower than the elevated surface. The foot portion  20  includes an arcuate portion  22  defining a plurality of exposed serrations  24 . Serrations  24  enable the foot portion  20  to grippingly engage the lower, ground level over a variety of pitch angles. The serrations  24  further prevent undesirable skidding and resulting lack of support. 
     As best seen in FIGS. 5,  5   a , and  9 , the traction plate  12  further includes oppositely disposed, downwardly formed, substantially coextensive apron portions  34 . Each of the apron portions  34  further defines a substantially coextensive, generally U-shaped channel  36 . As best seen in FIG. 9, a base portion  38  having a pair of bifurcated leg portions  40   a ,  40   b , extending therefrom, forms the U-shaped channel  36 . Each of the bifurcated legs  40   a ,  40   b  terminates in an arcuate distal end portion, corresponding to the integrally formed arcuate portion  22  of foot portion  20 . For added strength, often required when loading or unloading heavy loads, the bifurcated leg portions  40   a  may extend and substantially contact the underside of traction plate  12  as shown in FIG. 5 a . This alternate configuration allows a greater number of serrations to be formed in each inner arcuate portion  22  which, in turn, provides greater ramp strength and stability. 
     As illustrated in FIGS. 6-8, the coextensive panel portions  34  are each provided with at least one hole  42  through which a safety line  44  may pass. In the depicted preferred embodiment, a plurality of holes are provided and the safety line  44  is passed in opposite directions through each hole  42 . This provides the benefit of facially adjusting the safety line  44  length with the need for additional tools. As will be readily appreciated from the drawings, a longer safety line  44  length is required when the ramps  10  are spaced closely together while a shorter safety line is preferable when the ramps  10  are widely spaced apart. A hook  45 , clasp or similar securing means may be attached to the distal end of each safety line  44 . The safety line  44  and hook  45  may be attached to the raised surface, seen as truck bed  11  in FIGS. 2 and 4, for additional security in the event of an unforeseen shift of the ramp  10 . 
     Referring to FIGS. 6 and 7, the tongue section  18  of ramp  10  may be seen in greater detail. The tongue section  18  is integrally formed with, and extending from, the traction plate  12  and is preferably provided with an angled support area  26  that is adapted to receive and engage the raised surface. The angle of support area  26  is preferably such that a smooth transition may be made between the traction plate surface  28  and the raised surface for facile movement of articles from one level to another. The angled leg portion  27  acts as a stop resisting forward movement of the ramp  10 . 
     The peripheral margin  46  of tongue section  18  is preferably surrounded by a U-shaped binder  48  to provide increased friction between the tongue section  18  and elevated surface, to protect the peripheral margin  46  and to further prevent scratching or other damage to the elevated surface to which it is secured. As best seen in FIG. 8 a , the U-shaped binder  48  is formed of a conventional molded material defining a bail portion  49  having a pair of bifurcated legs  50   a ,  50   b  extending therefrom. The bifurcated legs  50   a ,  50   b  each terminate at their distal end  52  with an upstruck barbed portion  54  for retention of the binder  48  relative to the peripheral margin  46  of the tongue section  18 . The upstruck-barbed portion  54  extends longitudinally and coextensive with the distal end  52  of each bifurcated leg  50   a ,  50   b . The binder  48  preferably includes a coextensive reinforcement element  62 , seen as a metallic strip  62  in FIG. 8 a , for durability and added strength. Although a metallic reinforcement element  62  is preferred, any material of sufficient rigidity, such as stiff plastic may also be used. 
     As shown in FIG. 6, the U-shaped binder  48  may be secured to the peripheral margin  46  by way of an adhesive  56 . An alternate means of securing the U-shaped binder  48  is illustrated in FIG.  8 . In this embodiment, the peripheral margin  46  of the tongue section  18  is further provided with a series of longitudinally aligned slots  58 . The slots  58  are arranged to grippingly receive the upstruck-barbed portion  54  of the U-shaped binder  48 . When the binder  48  is used with the slotted tongue section, the barbed portion engages the slots to provide secure attachment. 
     As seen in FIGS. 1-4, the traction plate may be further provided with a handhold aperture  60  for ease of transport and adjusting prior to loading or unloading. The handhold aperture  60  may be preferably provided with a U-shaped binder  48   a , similar in construction and attachment to the binder  48  on the peripheral margin  46  of the tongue section  18 . 
     In the preferred embodiment, the traction plate top surface  28  is provided with a plurality of apertures  30 . As seen in FIGS. 7 and 9, the apertures  30  are preferably punched so as to leave extruded or flange portions  32  having an upper edge  32   a  configured to provide traction and enable breaking through debris or snow. The upper edge,  32   a , of aperture  30  is configured so as to provide a surface taper, whereby undesirable sharp edges which may otherwise cut tires or hands are avoided. The apertures  30  extend outwardly from the traction plate top surface  28  and are positioned in regularly spaced, preferably offset rows. It is to be understood that, although a circular aperture  30  is preferred, an aperture of any shape remains within the scope of this disclosure. 
     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.