Bridges – Gangway – ramp – or dock leveler
Reissue Patent
2001-09-06
2003-11-25
Shackelford, Heather (Department: 3673)
Bridges
Gangway, ramp, or dock leveler
C472S088000, C472S089000, C472S090000
Reissue Patent
active
RE038326
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a molded plastic ramp. In the prior art, ramps are known, however. Applicant is unaware of any ramp structure including all of the features and aspects of the present invention.
The following prior art is known to Applicant:
U.S. Pat. No. 3,023,343 to Freeberg
U.S. Pat. No. 3,663,015 to Bynder et al.
U.S. Pat. No. 4,129,916 to Schlesinger et al.
U.S. Pat. No. 4,285,514 to Romero
U.S. Pat. No. 5,033,146 to Fogarty et al.
U.S. Pat. No. 5,267,367 to Wegmann, Jr.
U.S. Pat. No. 5,483,715 to Fogarty et al.
U.S. Pat. No. 5,524,310 to Farnen
U.S. Design Pat. No. 246,638 to Hegedus
U.S. Design Pat. No. 257,874 to Sheehan et al.
U.S. Design Pat. No. 346,256 to Thomas, III et al.
U.S. Design Pat. No. 353,930 to Johnson.
In Freeberg, the ramp surface is convex as compared to the concave radiused ramp surface of Applicant's invention. Furthermore, Freeberg lacks the side and rear reinforcements disclosed herein.
Bynder et al. teach a bike jump. However, the pointed forward end thereof differs from the present invention. Furthermore, the ramp surface of Bynder et al. is flat.
Schlesinger et al. disclose an adjustable skateboard ramp having a radiused surface. The Schlesinger et al. device is not made in one-piece but, rather, consists of a complicated framework that must be assembled together. Furthermore, the ramp surface extends almost vertically and no side reinforcements are provided.
Romero teaches a ramp device for practicing wheeled sports. The present invention differs from the teachings of Romero as contemplating a one-piece molded ramp structure having reinforced side walls and supports extending laterally outwardly from the side and rear walls thereof.
Fogarty et al. '146 teach a vehicle service ramp that includes a separate reinforcing structure. In Applicant's invention, the ramp surface is radiused and the reinforcement is integral with the ramp.
Wegmann, Jr. teach a safety ramp and method for protecting hoses and conduits. The ramp surface of Wegmann, Jr. is not radiused and has a textured surface to provide traction. No side reinforcing means are contemplated therein.
Fogarty et al. '175 teach a service ramp that includes a flat textured ramp surface and reinforcing means within a chamber formed underneath the ramp. In the present invention, all of the reinforcing means are integrated into the side and rear walls thereof and the ramp surface is smooth and radiused.
Farnen teaches a modular halfpipe skateboard ramp and method of constructing. In Farnen, the ramp surface is radiused but extends about one-fourth of a circular revolution. Furthermore, Farnen teaches a constructed ramp made of several component parts assembled together. In contrast, the present invention comprises a single one-piece molded piece of plastic with reinforcements built into the walls thereof.
Hegedus teaches a bicycle ramp having a flat ramp surface with support legs at the rear thereof. The present invention differs from the teachings of Hegedus as teaching a one-piece molded plastic ramp having reinforcements built into the side walls and a radiused ramp surface.
Sheehan et al. teach a skateboard ramp having a variably radiused surface and including support legs mounted on the side walls thereof. The present invention differs from the teachings of Sheehan et al. as contemplating a one-piece molded ramp having a radiused surface and integral reinforcements in the side and rear walls thereof.
Thomas, III et al. teach an access ramp for handicapped persons including a flat ramp surface with projections extending upwardly thereof for traction. The present invention differs from the teachings of Thomas, III et al. as contemplating a one-piece molded ramp having a radiused smooth ramp surface with side walls having reinforcements built therein and with the forward edge of the ramp surface extending forwardly of side supports therefor.
Johnson teaches a jump ramp for wheeled vehicles. The Johnson ramp includes elongated rib-like reinforcements on the underside. Furthermore, Johnson includes a textured flat ramp surface with a forward edge that is spaced upwardly from a ground surface. The present invention differs from the teachings of Johnson as contemplating a radiused smooth ramp surface with side walls with built-in reinforcements and with the forward edge of the ramp being flush with a ground surface.
Ramps are also made of wood using plywood and elongated wood pieces to fabricate such a ramp. Such ramps are heavy and cumbersome and, when exposed to adverse weather conditions, quickly deteriorate.
It is with the problems of the prior art in mind that the present invention was developed.
SUMMARY OF THE INVENTION
The present invention relates to a molded plastic ramp. The present invention includes the following interrelated objects, aspects and features:
1. In a first aspect, the present invention is made in a onestep molding process. In the preferred mode of construction, the technique of vacuum forming is employed due to its relative economy as compared to injection molding. Due to the relatively large size of the inventive ramp as compared to small plastic parts that are commonly injection molded, the use of vacuum forming can result in large financial savings. The present invention is specifically designed to more than withstand anticipated forces when made in a vacuum forming process.
2. The inventive ramp includes side and rear walls with built-in reinforcements. The reinforcements consist of depressions in the outer walls thereof that are seen, in the underside, as projections. In other words, these depressions extend completely through the material and act as reinforcing ribs. In the preferred embodiment, three such depressions are formed in each of the side walls and the rear wall. To facilitate the vacuum forming process, the side wails may be slightly angled outwardly from the ramp surface toward the bottom edge thereof.
3. The ramp surface itself is radiused to provide a gentle curve from the bottom to the top thereof. In one embodiment, the curvature of the ramp is that of a 9′ radiused circle. The length of the ramp approximates about 5% of the circumference of such a circle, as such, the top of the ramp, at its rearward edge, does not present a sharp upward angle to the user. The ramp surface is smooth and untextured to provide minimal friction with the wheels of the user's vehicle such as, for example, a skateboard or rollerblades or other wheeled vehicle.
4. A support structure is provided for the present invention including laterally extending supports that extend rearward of the rear wall and laterally of the side walls. The undersides of these supports may be coated with a ground gripping material such as, for example, a roughened rubber material. The forward edge of the ramp surface extends forwardly of the forward extent of the lateral supports extending laterally from the side walls. In this way, the forward lip of the ramp surface provides direct transition from the adjacent ground surface to the ramp surface without a “bump”.
5. In the preferred embodiment of the present invention, the inventive ramp is made of a hard, strong plastic material such as, for example, Acrylonitrile Butadiene Styrene, otherwise known as “ABS” plastic. Other hard, strong plastic materials may be substituted such as, for example, thermal plastics or polycarbonates, however, “ABS” plastic was chosen for its combination of strength, aesthetics and economy.
Accordingly, it is a first object of the present invention to provide a molded plastic ramp.
It is a further object of the present invention to provide such a ramp made in a one-step molding process.
It is a still further object of the present invention to provide such a ramp wherein the molding process comprises vacuum forming.
It is a still further object of the present invention to provide such a ramp including a smooth radiused ramp surface having a forward edge flush with an adjacent ground surface.
It is a still further object of the present invention t
Shackelford Heather
Singh Sunil
Spiegel H. Jay
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