Material or article handling – Self-loading or unloading vehicles – Conveyor
Reexamination Certificate
2000-04-17
2001-06-26
Bratlie, Steven A. (Department: 3652)
Material or article handling
Self-loading or unloading vehicles
Conveyor
C296S061000
Reexamination Certificate
active
06250874
ABSTRACT:
BACKGROUND OF THE INVENTION
For as long as pickup trucks have existed, there has been a need for a ramp to load/unload them. In the past, such ramps were attached to truck tailgates. Alternately, the tailgate itself was removed; and the ramp, when not in use, was folded upwardly in place of the tailgate. But matching a ramp with the body of a particular vehicle is difficult, and truck owners are generally reluctant to permanently alter their vehicles.
An approach which requires substantially less alteration entails the use of heavy steel bumpers. Once commonplace, such bumpers can serve as a convenient structure on which to attach a ramp. Dudley, in U.S. Pat. No. 4,795,304, for example, uses the rear bumper for this purpose. But with the advent of plastic bumpers, his type of ramp support lost favor. Indeed, without a heavy steel structure, bumpers no longer can be used to mount a ramp or even a conventional towing ball.
In response to unmet towing needs, a combination trailer hitch receiver/hitch arm, in which the hitch receiver is fastened to the undercarriage of a vehicle, was subsequently developed. Such a hitch receiver is now available at relatively low cost for nearly all truck models. Two versions currently dominate the market. Classes II and III hitch receivers present a 1-¼ inch by 2 inch rectangular opening and a 2 inch square opening, respectively, into which one end of an appropriately sized hitch arm can be slip-fitted. Once the hitch arm has been so slip-fitted, two sets of openings, located in the hitch receiver and arm, respectively, can be brought into alignment, so that a locking pin can be inserted therethrough and employed to hold the hitch receiver and arm in assembled relation. In a popular version of the hitch arm, a towing ball is mounted on the end thereof distal from the hitch receiver.
But none of the prior art hitch arm/hitch receiver combinations provides for a ramp which can be used to load and unload a pickup truck.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a ramp assembly which can be mounted on a pickup truck or similar vehicle without modifying its tailgate, bed or bumper.
A further object of the present invention is to provide such a ramp assembly which neither interferes with the use of the truck nor hinders the opening or closing of its tailgate when the ramp is in its stored position.
In accordance with the present invention, there is provided a ramp assembly having a “L”-shaped hitch arm with two branches, one of which is longer than the other. The elongated branch can be adjustably slip-fitted into a class II, or, alternately, into a class III, hitch receiver when the latter is attached to the frame of a pickup truck or the like. A hitch pin is utilized to hold the hitch arm and receiver in assembled relation. Supported by the hitch receiver, the “L”-shaped hitch arm is held in such a way that its second, shorter branch extends rearwardly of the truck tailgate. Distal from the hitch receiver, the shorter branch terminates in an opening which is disposed transversely to its longitudinal centerline.
The improved ramp assembly further comprises a “T”-shaped support having a horizontal bar and one leg which extends downwardly therefrom. Prior to use, the leg is inserted into the transverse opening in the shorter branch, slideably engaging it. Secured atop this horizontal bar are at least two bearing posts which extend upwardly therefrom and are spaced apart from each other. Holes defined by the posts are aligned with each other so that they can slideably receive an elongated shaft.
The improved ramp assembly still further comprises at least one set of first and second panel members which are hinged together and foldable. The transverse width of the first panel member, at the end thereof distal from the hinged joint, is less than the distance separating any two contiguous bearing posts on the “T”-shaped support. Together the panel members define a structure across which, when they are locked in a fully extended position, cargo can be transferred. Formed integrally with the distal end of the first panel member is a pair of plates, each of which defines a hole for slideably receiving the elongated shaft upon which the hinged panel members are rotatably supported.
In the preferred embodiment, means for locking the panel members in a fully extended position includes a pair of hollow cylinders and a pin slideably engageable therewith. Mounted in tandem proximate with the hinged joint, one of the cylinders is rigidly attached to the first panel member and other to the second panel member. When the hinged panel members are fully extended, the longitudial centerlines of the two cylinders are aligned, so that the pin can be inserted into both of them simultaneously, locking the panel members in position.
In the preferred embodiment, the improved ramp assembly comprises two sets of first and second panel members separated by a third bearing post. The first panel member in each set is then slideable along the elongated shaft, so that the spacing between the two sets of panel members can be adjusted to accommodate widely varying cargo widths.
To facilitate storage, the panels can be secured in an upwardly folded position behind the tailgate of the vehicle on which the improved ramp assembly is mounted. Whether in their folded position or otherwise, the panels do not interfere with opening or closing the tailgate. Alternately, when the ramp assembly is not in use, it can be removed by pulling the hitch pin and disengaging the hitch arm from the hitch receiver.
REFERENCES:
patent: 4874284 (1989-10-01), New, Jr.
patent: 5096362 (1992-03-01), Best
patent: 5458389 (1995-10-01), Young
patent: 5649732 (1997-07-01), Jordan et al.
patent: 5971465 (1999-10-01), Ives et al.
patent: 6076215 (2000-06-01), Blankenship et al.
Bratlie Steven A.
Leon Harry I.
Steadman Vivian L.
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