Abstract:
A ramp assembly for loading and unloading vehicles includes a pair of ramp sections pivotally secured to each other by a hinge assembly and a dolly also secured to the hinge assembly which assists in deploying and stowing the ramp assembly and also in supporting the sections of the ramp assembly as the ramp is used to load and unload a vehicle.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This is a non-provisional application claiming priority to provisional application Ser. No. 61/869,324, filed Aug. 23, 2013. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention relates generally to the loading and unloading of trucks and trailers. More particularly, the present invention relates to an improved ramp and deployment mechanism for the ramp used when loading and unloading cargo. 
     II. Related Art 
     Various forms of ramps have been employed to assist with the loading and unloading of cargo from vehicles. An example of a prior art ramp is illustrated in  FIGS. 1 and 2 . As shown in  FIG. 2 , the ramp  10  is coupled to the floor of a vehicle  12  and extends downwardly and rearwardly from the floor of the vehicle to the ground  14 . More specifically, one end of the ramp  16  includes a plate  17  which rests on the floor of the vehicle. The other end of the ramp  18  is tapered to rest on the ground. The ramp illustrated in  FIGS. 1 and 2  has a pair of side rails  20  and  22  joined by an interconnecting load bearing surface  24 . To make the entire ramp lighter in weight, the load bearing surface  24  is in the the form of a mesh rather than a solid plate. As illustrated in  FIG. 2 , the load bearing surface is wide enough so that a person can walk up and down the ramp while pushing a two-wheeled dolly carrying cargo. 
       FIG. 3  shows an assembly which may be used to assist in storing the ramp as the vehicle is being driven and to deploy the ramp for use in loading and unloading cargo from the vehicle. This assembly includes a frame  30  which is typically coupled to the vehicle below the floor. A linkage  32  is also shown. To store the ramp  10  of  FIGS. 1-3 , the end  18  of the ramp is lifted from the ground and the entire ramp is then slid forward between the floor of the vehicle and the frame  30  so that the ramp  10  is only supported by the frame  30  while the vehicle is being driven. 
     Ramps such as those shown in  FIGS. 1-3  are very popular. However, they are somewhat difficult to deploy, particularly when the ramps are of a longer length, due to the weight of the ramp, the need to lift and lower the back end  18  of the ramp and the need to raise and lower the front end  16  of the ramp between a use position in which the plate  17  resides on the top of the floor of the truck and the stowed position in which the plate  17  (along with the remainder of the ramp) resides between the floor of the truck and the frame  30 . Thus, there is a real need for devices which reduce strain on the user&#39;s body and the strength required for the user to deploy and stow the ramp. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved ramp for loading and unloading cargo from a vehicle. The improved ramp includes a first ramp section having a first end and a second end. The first end of the first ramp section includes a member for securing the ramp to or at a height proximate to the floor of a cargo vehicle. The second end of the first ramp section is coupled to a hinge arrangement. The ramp also includes a second ramp section having first and second ends. The second end of the second ramp section is also coupled to the hinge such that the second ramp section can be pivoted with respect to the first ramp section between a stowed position in which the first and second ramp sections are in face-to-face registration with each other and a second position in which the first and second ramp sections extend from each other at approximately 180°. The first end of the second ramp section is tapered (as is the first end of the first ramp section) such that when the first end of the first ramp section is positioned adjacent to the floor of a vehicle, the second end of the second ramp section will rest firmly on the ground. The hinge arrangement connecting the first and second ramp sections may be provided with stops which ensure that the two ramp sections will be retained in the extended position approximately 180° from each other as the vehicle is loaded and unloaded. 
     Additionally, a dolly is secured to the hinge arrangement connecting the first and second ramp sections. The dolly can be rotated between a stored position in which the dolly, too, is in face-to-face registration with the first and second ramp sections when they are in their stowed position. Likewise, the dolly can be rotated about the hinge arrangement into a ground-engaging position to assist with deployment of the ramp and also support the center of the ramp during the loading and unloading process. The dolly includes a first arm coupled to the hinge arrangement at one of its ends and a hinge bracket at its other end. The hinge bracket is, in turn, coupled to an elongate wheel arm which also can pivot between a stowed position, a position in which the wheel engages the ground to assist with sliding the ramp toward and away from the vehicle, and a support position in which the hinge bracket of the dolly engages the ground to further assist in stabilizing the ramp. 
     The foregoing assembly provides an easy-to-deploy and stow ramp for trucks suitable for use when loading and unloading cargo. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description and with reference to the following drawings in which like numerals and the several views refer to corresponding parts. 
         FIG. 1  illustrates a prior art vehicle ramp. 
         FIG. 2  illustrates the prior art vehicle ramp of  FIG. 1  attached to a vehicle and being used to load or unload cargo from the vehicle. 
         FIG. 3  illustrates the prior art ramp of  FIGS. 1 and 2  together with a frame typically coupled beneath the floor of a vehicle and used to stow the ramp below the floor of the vehicle when the ramp is not being used to load or unload cargo. 
         FIG. 4  is a side view showing the ramp of the present invention in its stowed position. 
         FIG. 5  shows the ramp of  FIG. 4  as one begins the process of deploying the ramp for use by rotating the dolly between the stowed position in  FIG. 4  to the position shown in  FIG. 5 . 
         FIG. 6  is another side view of the ramp of  FIG. 4  showing the dolly with the wheel arm extended. 
         FIG. 7  shows the ramp of  FIG. 4  with the wheel of the dolly in its ground-engaging position as the ramp is being elevated from a stowed position to a truck floor-engaging position. 
         FIG. 8  shows the ramp of  FIG. 4  with the first ramp section having reached the floor-engaging height. 
         FIG. 9  shows the ramp of  FIG. 4  with the second ramp section partially rotated toward its ground-engaging position. 
         FIG. 10  shows the ramp of  FIG. 4  fully deployed for use in loading and unloading vehicles. 
         FIG. 11  shows a more detailed view of the dolly of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     This description of the preferred embodiment is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom”, as well as derivative thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “joined”, and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece unless expressly described otherwise. 
     As illustrated in  FIGS. 4-11 , the ramp  100  includes a first ramp section  102  and a second ramp section  104 . Each ramp section has a pair of side rails similar to the side rails  20  and  22  in  FIG. 1 . In the drawings, one of the side rails  106  of the first ramp section  102  and one of the side rails  108  of the second ramp second  104  is shown. The opposing side rails are essentially the same as the side rails  106  and  108 . Extending between the two side rails of the two ramp sections  102  and  104  is a load bearing surface or platform  109  ( FIG. 11 ) similar to the platform  24  shown in  FIG. 1 . 
     The first ramp section  102  has a first end  110  and a second end  112 . The first end is tapered at an angle  114  so that the terminal portion  116  of the first end  110  may rest on the floor of a truck or trailer being loaded. A pin  110  may also be provided which enters an orifice in the floor of the truck or otherwise engages the truck to lock the terminal end in place with respect to the floor of the truck. The pin  118  is easily removed when necessary to store the ramp by simply lifting on the first end of the ramp to draw the pin  118  out of the hole so that the terminal end  116  can be removed from the top of the floor of the truck. 
     The second ramp section  104  also has a first end  120  and a second end  122 . The first end  120  includes a first taper  124  which allows the first end  120  of the second ramp section to rest firmly on the ground when the ramp is fully deployed. The first end  120  of the second ramp section  104  includes a second taper  125 . The second taper is useful to enable a user of the ramp to easily transition two-wheeled dollies or the like onto the ramp from the ground or off of the ramp to the ground when the ramp is fully deployed in the use position. 
     The second end  112  of the first ramp section  102  and the second end  122  of the second ramp section  104  are joined together by a pair of hinges, one of which (hinge  130 ) is shown in the drawings. These hinges connect the rails  106  and  108  of the two ramp portions together so that the ramps can pivot with respect to each other between the position shown in  FIG. 4  in which the ramp sections  102  and  104  are in face-to-face registration with each other and the position shown in  FIG. 10  in which the two ramp sections  102  and  104  extend from each other at approximately at a 180° angle. The hinges  130  and the ends  122  and  112  of the ramp sections are designed so that the ramp sections will not rotate about hinge  130  beyond about 180°. 
     The arrangement of the present invention also includes a dolly  140 . While the dolly arrangement is visible in  FIG. 4 , it is more readily seen in the other drawings. Only one side of the dolly is shown. The other side of dolly  140  is coupled to the other side of the second ends of the ramp section and is identical in construction to the side of the dolly shown in the drawings. Thus, both sides of the two ramp sections are supported by the dolly  140  when the dolly  140  is deployed. 
     As illustrated, each side of the dolly  140  includes a first arm  142 , a second arm (which may be referred to as a wheel arm)  144  and a wheel assembly  146  mounted to the end of the wheel arm  144 . Substantial mechanical advantage is achieved by providing a wheel arm  144  rather than mounting the wheel assembly  146  directly to the end of first arm  142 . The first arm  142  includes a hinge member  148  which is coupled to the hinge assembly  130  so that the entire dolly can be moved from the position shown in  FIG. 4  through the position shown in  FIGS. 5-8  to the position shown in  FIG. 9 . Likewise, the dolly can be rotated back about the hinge assembly  130  from the position shown in  FIGS. 9 and 10  through the positions shown in  FIGS. 5-8  to the position shown in  FIG. 4 . Stops interacting with the dolly may be provided to prevent over rotation of the dolly beyond the position shown in  FIGS. 9 and 10 . When the wheel of the wheel assembly  146  engages the ground as in  FIG. 8 , better weight distribution results than if the wheel were directly beneath the ends  112  and  122  of the ramp sections, making it easier to complete deployment of the ramp assembly or stow the ramp. 
     The drawings also show that the dolly  140  includes a hinge joining the first arm  142  of the dolly and the wheel arm  144  of the dolly. This permits the wheel arm  144  to be rotated relative to the first arm  142  about the hinge  150  between the position shown in  FIGS. 4 and 5  to the position shown, for example, in  FIG. 6 . It is interesting to note that the hinge  150  includes a surface  152  which engages the ground such that the hinge  150 , arm  142  and hinge  130  help support the ends  112  and  122  of the ramp members  102  and  104  in an elevated position above the ground. 
     More specifically, as the second ramp section  104  is rotated to the deployed position, the wheel of wheel assembly  146  lifts off the ground so that the ends  112  and  122  of the ramp sections are supported above the ground by the arm  142  and surface  152  of the hinge  150 . Likewise, as ramp section  104  is returned to its stowed position in face-to-face registration with ramp section  102 , the ramp section acts as a lever causing the wheel to engage the ground and the ends  112  and  122  to be lifted by the dolly  140 . 
       FIG. 11  shows in greater detail the construction of the dolly  140 . As shown in  FIG. 11 , the first arm  142  is hollow and has a plunger bar  164  extending through the central opening of the tubular first arm  142 . The lower end of the plunger bar  164  engages the wheel arm  144 . The upper end of the plunger bar  164  is attached to a plunger plate  162 . The plunger bar  164  and plunger plate  162  collectively comprise a plunger. Joined to the second ramp section  102  near the second end is a plate  160  having a dog-ear cam surface which engages the plunger plate  162  as the second ramp section  104  is rotated from the position shown in  FIG. 10  back toward the position shown in  FIGS. 4-8 . The dog-ear plate  160 , plunger plate  162  and plunger bar  164  serve to rotate wheel arm  144  about hinge  150  to raise and lower the wheel assembly  146  between the position shown in  FIG. 10  and the position shown in  FIG. 8 . 
     Now that the various structures of the ramp have been explained, its operation will be further described. 
       FIG. 4  shows the ramp in its stowed position. Generally the ramp will be stowed between the floor of a vehicle and a frame such as the frame  30  shown in  FIG. 3 . Deployment begins by partially retracting the assembly from beneath the vehicle. This is achieved by pulling on the ends  112  and  122  of the ramp members until the dolly  140  clears the back of the vehicle. At this point, the center of gravity is such that the full weight of the ramp is supported by the frame (e.g., frame  30 ). 
     Next, the dolly  140  is deployed by rotating the first arm  142  of the dolly from the position shown in  FIG. 4  to the position shown in  FIG. 5 . The wheel arm of the dolly  144  is then rotated about hinge  150  between the position shown in  FIG. 5  and the position shown in  FIG. 6 . The arm  142  can then be further rotated about the hinge arrangement  130  until the dolly reaches the position shown in  FIG. 7 . 
     More specifically, as the arm  142  is rotated from the position shown in  FIG. 6  to the position shown in  FIG. 7 , the dog-ear on the plate  160  engages the plunger plate  162  forcing the plunger bar  164  downwardly and the wheel arm  144  to rotate about hinge  150  so the wheel of wheel assembly  146  ultimately reaches the position shown in  FIG. 7 . 
     Once the position shown in  FIG. 7  is reached, the user can pull on the ends  122  and  112  of the ramps sections to further retract the ramp  100  from the storage frame  30  on the underside of the truck&#39;s floor. Ultimately, the Wheel of wheel assembly  146  is in engagement with the ground and the rest of the dolly  140  is supported by the wheel above the ground. The length of wheel arm  144  ensures a weight distribution which makes it easy to continue deployment of the ramp assembly. The remainder of ramp  100  can then be more easily retracted from a location beneath the bottom of the floor of the truck because the ramp is supported by the wheels  146 . The frame will typically include a catch which may intersect with the pin  118  when the ramp  100  reaches the fully retracted position to prevent the end  110  of ramp member  112  from becoming dislodged and falling to the ground. At this point, the user can lift the end  110  of ramp section  102  up so that the terminal portion  116  of the ramp rests on the floor of the truck. The ramp  100  will then be in the position shown in  FIG. 8 . 
     The next step of the deployment process is to begin to rotate frame section  104  about the hinge assembly  130 . This is not only necessary to deploy ramp section  104 , but also serves to elevate the wheel  146  so that the ground-engaging surface  152  of the dolly is in contact with the ground. More specifically, the pressure applied by the dog-ear cam surface on hinge assembly  130  on the plate  160  is relieved so that gravity lowers the dolly  140  such that surface  152  engages the ground. At this point, the ramp  100  is supported by the floor of the vehicle at end  110  and by the ground-engaging surface  152  of hinge  150  and arm  142  of dolly  140 . With the ramp so supported, ramp section  104  can be further rotated about the hinge  130  as suggested by  FIG. 9  until it reaches the position shown in  FIG. 10  in which the first taper  124  at end  120  of ramp section  104  is also in engagement with the ground. With the ramp in the position shown in  FIG. 10 , a person can easily push a loaded two-wheeled dolly or the like up or down the ramp as part of a truck loading or unloading process. 
     Once loading and unloading is complete, the ramp is easily stored. This is achieved by first rotating ramp section  104  about the hinge  130  as suggested by  FIG. 9  to the position shown in  FIG. 8 . As such rotation occurs, the dog-ear cam plate  160  engages the plunger plate  162  and moves the plunger bar  164  causing rotation of wheel arm  144  and wheel assembly  146 . Sufficient rotation of ramp section  104 , which acts as a lever, causes the wheel of wheel assembly  146  to again engage the ground and the ends  112  and  122  of the ramp sections  102  and  104  to rise. Optimal weight distribution is again provided due to the length of wheel arm  144 . The end  110  of the ramp section  102  is then easily removed from the floor of the truck and placed onto the frame  30 . At this point, the entire ramp is supported by the frame  30  and the wheels of dolly  140 . By pushing on the ends  112  and  122  of the ramp sections, the wheels not only support the ramp, but also allow it to more easily be moved between the truck and the frame. Eventually, the ramp is moved to a point where it is fully supported by the frame. The dolly can then be stowed as illustrated in  FIGS. 6 and 5 . Once the dolly is in the stowed position shown in  FIG. 4 , the ramp can then be pushed further onto the frame  30  so it is fully stowed beneath the floor of the vehicle. 
     From the foregoing, it will be appreciated that although specific examples have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of this disclosure. For example, the specific structures of the two ramp sections and the frame may be varied without deviating from the invention. It is, therefore, intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents that are intended to identify the invention.