Abstract:
A mobile ramp having sloped and horizontal platforms is presented for elevating a vehicle from the floor to provide easy access to the underside of the vehicle to service the same. The ramp is provided with wheels that are pivotably mounted to the frame of the ramp so that they can be extended to raise the ramp off the floor for ease of mobility. The wheels are also retractable to allow the ramp to be safely secured to the floor when it is in use. The retractable action of the wheels is mechanically responsive to the weight of a vehicle as it is wheeled on and off of the ramp, providing for a hands-free operation. While it is mobile, the ramp is further designed to be durable and simple to manufacture.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to ramps for vehicles and more specifically to a mobile ramp for vehicles that can be manually positioned so that a vehicle can be rolled thereon to elevate one or both ends of the vehicle to provide access to the underside of the vehicle.  
           [0003]    2. Description of the Prior Art  
           [0004]    Many aspects of servicing and maintaining a vehicle require access to the underside of the vehicle. The simple task of changing the vehicle&#39;s oil, for example, can become nearly impossible unless the mechanic can place himself beneath the vehicle with sufficient room to work.  
           [0005]    Many different tools and devices are known that can be used to elevate one or both ends of a vehicle. However, many of these tools and devices suffer from one or more shortcomings. The common jack, while portable and accessible to the do-it-yourself mechanic, is limited in application and safety due to its narrow base. Typically, jacks are capable of elevating only one end of a vehicle and may be limited to raising just one side of one end of a vehicle. If a single jack is disposed at one end of a vehicle along its centerline, the vehicle will be susceptible to tipping and falling to one side. The use of two jacks to increase stability can be awkward and impractical.  
           [0006]    Mechanical and hydraulic lifts provide sufficient power and stability to safely lift an entire vehicle off the ground. U.S. Pat. Nos. 5,340,082; 5,297,653; 4,901,980; and Des. No. 349,802 all teach different forms of vehicle lifts. Many similar lifts can raise a vehicle to a height that allows a mechanic to comfortably walk beneath the vehicle and work on its underside. However, these lifts are typically expensive and require a large amount of floor space. Moreover, lifts are usually built into the floor of the garage and are incapable of being moved from one end of the garage to another. Accordingly, lifts are usually not practical for smaller garages or the do-it-yourself mechanic.  
           [0007]    Ramps often provide a middle ground between simple jacks and complex lifts. Fixed ramps can be easily fashioned from a pair of rails that are positioned several feet above the floor of the garage, with a sloped platform or a pair of tracks leading to a generally horizontal platform which supports one end of a vehicle. This design allows the mechanic to safely lay beneath the vehicle and work on its underside. The convenience of being able to selectively position the ramp, or easily remove it from the garage entirely, prompted the design of wheeled ramps. However, such a design requires that the ramp be of sufficient strength to support the weight of a vehicle while remaining relatively light and easy to maneuver. Moreover, wheeled ramps must be designed so that once the ramp is placed in position, the wheels can be easily disengaged from the floor so that the ramp is adequately anchored for use in elevating a vehicle.  
           [0008]    U.S. Pat. No. 5,447,406 teaches a wheeled ramp that is selectively positionable and sufficiently mobile to allow a mechanic to move the ramp to a convenient storage location when it is not in use. However, its design requires a complexity of lever-arms that must be hand-operated by the mechanic to engage and disengage the wheels in order to position and secure the ramp. The complexity of the lever-arm system is naturally prone to mechanical failure and human error. The manufacture of such a wheeled ramp also requires precise tooling and construction to provide continued effective use.  
           [0009]    Accordingly, there is a need for an improved wheeled ramp for elevating vehicles with a simple design that allows for ease of operation and manufacture.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention relates to wheeled ramps for elevating and servicing a plurality of different types of vehicles. More particularly, the device of the present invention relates to a simplified structure for wheeled ramps for vehicles that provides ease of use and manufacture without sacrificing safety and dependability.  
           [0011]    The base of the ramp is comprised of horizontally disposed base plates that are in spaced relation to each other, forming a gap therebetween. A sloped platform extends upwardly from the base to a point above the gap between the base plates. A generally horizontal platform is connected to the elevated end of the sloped platform and extends outwardly over the base. A plurality of paired, vertically disposed supports extend upwardly from the base and are connected to the sloped and horizontal platforms.  
           [0012]    The ramp is provided with a pair of retractable wheels that allow the ramp to be selectively mobile. The wheels are easily retracted into the base so that the ramp is secured against the floor of the garage when the ramp is in use. A spring, disposed between the wheels and the horizontal platform, extends when the vehicle is wheeled off the ramp. This action brings the wheels into functional engagement with the floor of the garage, permitting the ramp to once again be moved. An elongated, retractable handle is provided at one end of the ramp to allow the mechanic to reposition the ramp.  
           [0013]    It is therefore an object of the invention to provide an improved ramp for elevating vehicles that is easy to use.  
           [0014]    A further object of the invention is to provide an improved ramp for elevating vehicles that is easy to manufacture.  
           [0015]    A further object of the invention is to provide an improved ramp for elevating vehicles that is selectively mobile.  
           [0016]    A further object of the invention is to provide an improved mobile ramp for elevating vehicles that is stable and durable.  
           [0017]    A further object of the invention is to provide a ramp for elevating vehicles having retractable wheels that allow the ramp to be safely secured to the ground when the ramp is in use, and easily moved when it is no longer in use.  
           [0018]    A further object of the invention is to provide a ramp for elevating vehicles having wheels that retract automatically when a vehicle is wheeled onto the ramp, and extend automatically when the vehicle is wheeled off of the ramp.  
           [0019]    These and other objects of the present invention will be apparent to those skilled in the art. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a perspective view of the present invention;  
         [0021]    [0021]FIG. 2 is a side view of the present invention in its mobile position with its wheels and positioning handle extended;  
         [0022]    [0022]FIG. 3 is a side view of the present invention in secured engagement with the ground with its wheels and positioning handle retracted;  
         [0023]    [0023]FIG. 4 is a top view of the present invention;  
         [0024]    [0024]FIG. 5 is a side view of the present invention, with an alternate wheel assembly, in its mobile position; and  
         [0025]    [0025]FIG. 6 is a side view of the present invention, with an alternate wheel assembly, in its secured position. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]    The numeral  10  refers generally to the ramp of the present invention. It should be understood that the present invention is well-suited for elevating most types of vehicles including, but not limited to, cars, trucks, motor homes, buses, and trailers. However, for simplicity of description, the present invention will be described as it is used to elevate “vehicles”.  
         [0027]    As shown in FIGS.  1 - 4 , the ramp  10  is comprised of an upper deck  12 , having a sloped platform  14 , a generally horizontal platform  16 , and a base  18 . Side retention plates  17  and end plate  19  are provided to help prevent the wheels of a vehicle from leaving upper deck  12 . In its preferred embodiment, the base  18  is comprised of at least two base plates  20  and  22  arranged in spaced relation with one another to form a gap  24  therebetween. It is contemplated, however, that the base  18  could be formed from a single base plate or an infinite number of smaller base plates. A plurality of paired, horizontally spaced and vertically disposed supports  26  are secured to the base  18  and support the upper deck  12  so that the upper deck  12  is positioned directly above base  18  and spaced therefrom by a particular distance. It is contemplated that a single support  26  could be constructed to adequately support upper deck  12  over base  18 , however, it is preferred that a plurality of paired supports  26  be used. It is further contemplated that the sides of base  18  could be extended in a substantially vertical direction to connect the same to the upper deck  12  (not shown), thus supporting the upper deck  12  above the base  18  without the use of paired, horizontally spaced supports  26 . In any of the aforementioned embodiments, it is contemplated that in the construction of ramp  10 , the distance that upper deck  12  and base  18  are spaced from one another can be varied according to a particular intended use for ramp  10 .  
         [0028]    As shown in FIGS. 1 and 4, base plate  20  extends beyond the lower edge of sloped platform  14  and inward under the upper deck  12  to a first pair of vertical supports  26  and gap  24 . It is preferred that base plate  20  extend a significant distance beyond the lower edge of sloped platform  14  to form a tab  28 , as shown in FIG. 1. Tab  28  provides a surface for the wheels of the vehicle to roll onto, thus securing ramp  10  to the ground while the vehicle ascends sloped platform  14 , and preventing the vehicle from pushing the ramp  10  out of position. It is also contemplated that tab  28  could be formed from an article separate from but secured to base plate  20  or sloped platform  14 . This separate article could be made from a flexible material such as a rubber mat or a rigid plate similar to those used to construct upper deck  12  and base  18 . The separate article could be connected to the base plate  20  or sloped platform  14  in a fixed position or in a hinged manner, which would allow for storage of tab  28 .  
         [0029]    Ramp  10  is further provided with a retractable wheel assembly  30  so that ramp  10  can be easily moved from one location to another. As shown in FIGS.  2 - 4 , wheel assembly  30  is comprised of an elongated tongue  32 , having a first end  34  and second end  36 , which is pivotally connected at its first end  34  to the first pair of vertical supports  26 . An axle  38  is rotatably mounted within the second end  36  of tongue  32 . A pair of wheels  40  are disposed at either end of axle  38 . Tongue  32  extends above base  18  a sufficient distance to allow the wheels  40  to be positioned within gap  24 , as shown in FIGS.  1 - 3 . A spring  42  is secured to the upper surface of tongue  32 , closely adjacent the second end  36  thereof. Spring  42  operatively engages the lower surface of upper deck  12  with sufficient force to push the second end  36  of tongue  32  in a downward direction, extending wheels  40  through gap  24 . In this position, the entire weight of ramp  10  can be supported by wheel assembly  30  so that ramp  10  can be moved from one location to another, rolling along wheels  40  as shown in FIG. 2.  
         [0030]    When ramp  10  is not in use, the wheels  40  extend through gap  24 . When a vehicle is wheeled onto the ramp  10 , the weight of the vehicle overcomes the spring force of spring  42 . This force compresses spring  42  and raises the second end  36  of tongue  32  with respect to the ramp  10 , thus retracting wheels  40  into the ramp  10 , as shown in FIG. 3. With the wheels retracted, base  18  is firmly secured to the floor. When the vehicle is wheeled off the ramp  10 , the spring  42  decompresses and the wheels  40  are again extended through gap  24 , enabling the ramp  10  to be easily moved from one location to another.  
         [0031]    In an alternative embodiment (shown in FIGS. 5 and 6), wheel assembly  30  is comprised of an elongated leaf spring  54 , having first and second ends. The first end of leaf spring  54  is adapted with a bracket or other suitable means so that the first end can be secured to the base  18 . It is contemplated, however, that the first end of leaf spring  54  could be secured to a vertical support  26  or upper deck  12 . The second end of leaf spring  54  is adapted with a bracket or other suitable means for rotatably securing axle  38  thereto. It is further contemplated that the first and second ends of leaf spring  54  could be secured to the ramp adjacent both sides of gap  24  with axle  38  being disposed intermediate the first and second ends (not shown). Regardless, leaf spring  54  enables the wheel assembly to be mechanically responsive to the weight of a vehicle being received by ramp  10  as described above.  
         [0032]    In another embodiment, it is contemplated that base  18  could be provided without a gap  24  therein. Without a gap  24 , it is necessary to extend the length of axle  38  such that the wheels  40  extend beyond the sides of base  18  so that they may be selectively engaged with the floor. Accordingly, when the wheel assembly is in the extended position, axle  38  is positioned closely adjacent the base  18  and the ramp  10  may be wheeled into position. When the wheel assembly is in the retracted position, axle  38  is positioned away from base  18 , thus allowing wheels  40  to retract and base  18  to engage the floor.  
         [0033]    To assist in moving the ramp  10  while it is being supported by wheel assembly  30 , the ramp  10  is provided with a retractable handle  44 , having a first end  46  and second end  48 . Handle  44  is slidably secured to a collar  50 , which is pivotably secured to bracket  52 . In its stored position, handle  44  is secured along one side of ramp  10 , between the upper deck  12  and the base  18 , with its second end  48  closely adjacent collar  50 . In use, the handle  44  is first slid through collar  50  until the first end  46  of handle  44  is closely adjacent collar  50 . The second end  48  is then lifted, pivoting handle  44  and collar  50  upwardly and arcably to a desired height for the user. In this position, handle  44  can be used to pull or push ramp  10  to a desired location. For the user&#39;s comfort and grip stability, the second end  48  can be adapted with a layer of flexible and resilient material, such as rubber, Neoprene, or other available natural or synthetic materials. It is also contemplated that the grip could be made of durable, non-flexible materials such as metal or hardened plastic.  
         [0034]    Water, oil, and other fluids are commonly spilled when servicing a vehicle. Accordingly, it is contemplated that the upper deck  12  could be provided with grooves or channels (not shown) disposed therein to direct the fluids away from the surface of the upper deck, thus maintaining a reasonable degree of traction between the wheels of the vehicle and the surface of upper deck  12 . It is also contemplated that a mat of a water-resistant material (not shown), having dimensions sufficient to cover the upper surface of upper deck  12 , could be provided with similar grooves or channels for directing fluids away from the upper deck  12 . In the preferred embodiment, the mat is at least used as a traction pad that is adhered to the lower surface of base  18  to allow fluids to pass between the base  18  and the floor, thus improving the coefficient of friction between the ramp  10  and the floor. Adhering the mat to the lower surface of base  18  further protects the surface of the floor from marks that could be caused by the base  18  during normal use of the ramp  10 .  
         [0035]    In the drawings and in the specification, there has been set forth preferred embodiments of the invention and although specific items are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and proportion of parts, as well as a substitution of equivalents, are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims.  
         [0036]    Thus it can be seen that the invention accomplishes at least all of its stated objectives.