Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-04-05
2001-04-10
Swann, J. J. (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S163000
Reexamination Certificate
active
06213486
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a step assembly for a recreational vehicle and more particularly to a step assembly that is self-concealing when in its fully retracted position.
BACKGROUND OF THE INVENTION
The doorway threshold of recreational vehicles is typically high above the ground. Access to these type of vehicles can be difficult and even unsafe, especially for older persons who often use such vehicles. A series of permanent steps attached beneath the doorway to permit easy access would not be practical, since the steps would decrease the effective clearance of the vehicles and extend the width or length of the vehicle as well.
The desirability of having steps for recreational vehicles that may be folded out of the way when not in use has long been recognized. Such steps should fold readily, store compactly, and permit easy safe access to the vehicle. The steps should not increase the overall width of the vehicle when not in use, since the vehicle frame may already extend to the maximum width allowed by regulation. The retracted width of the steps should be such that, when not in use, the rear of the steps do not interfere with the frame of the vehicle. The depth of the steps is another safety and easy of access consideration. Ideally, each step should be deep enough to permit the entire foot of the user to have tread access, not just the heel or toe of the foot, when both ascending and descending. This is especially important when descending, so that the user is kept from pitching forward.
Steps for recreational vehicles such as motor homes, campers, vans, and the like, have included in the past, positionable features to enhance both step function and step stowage when the vehicle is underway. For the most part, such step assemblies have been manually positioned, but some powered step assemblies are also known in the prior art. One drawback to known steps is their limited extension capability, resulting in a step having only limited step surface area and requiring great care on the user's part in boarding or departing the vehicle.
Designs have been developed in an attempt to address some of the above-described considerations. For example, U.S. Pat. No. 3,876,230 (Phillips) discloses foldable camper steps that pivot on one another until they reach a fully retracted position. Each of the steps is formed from an L-shaped member. However, several problems exist with the application of the Phillips step assembly to a recreational vehicle. The door of a recreational vehicle is typically on the side. As such, very little or no increase in width beyond the door can be allowed by the steps when they are not in use. The steps of the Phillips device, even when fully retracted, extend at least the width of one step beyond the door. Another problem with the Phillips steps is in the shallowness of the depth of the step treads. A user may not be able to fit his or her entire foot onto the tread.
U.S. Pat. No. 3,408,959 (Cripe et al.) discloses a folding staircase which functions as a raised step for use with high-level platforms, as well as a pair of steps for lower-level platforms. The Cripe step assembly includes an upper tread and a lower tread linked together and actuated by the flotation of a pivot arm and an associated link through a chain drive, powered by a motor. When these steps are in a fully retracted position, an outside wall or member forms a part of the exterior of the vehicle.
U.S. Pat. No. 4,106,790 (Weiler) discloses a retractable vehicle step that swings into a retracted position. The Weiler step is mounted on the side of a recreational vehicle and stowed beneath the door under the side of the vehicle when not in use. However, since only one steps is disclosed, safe and convenient access may be somewhat less than desirable. If the frame height of the step is kept within a reasonable range for ground clearance purposes, the distance from the step to the ground may be excessive. If the step did project lower, the distance from the door threshold to the step may be excessive.
U.S. Pat. No. 4,424,751 (Blöchlinger) discloses a step assembly for rail cars, which is raised and lowered by two parallel guide brackets. This step assembly contains an upper and a lower tread. When the lower tread is in its retracted position the bottom surface of the step conforms to the exterior of the rail car. However, the Blöchlinger step assembly does reduce the amount of usable floor space within the rail car due to the operation and structure of the step assembly.
U.S. Pat. No. 3,807,757 (Carpenter et al.) also discloses a step assembly for campers, trucks, and other recreational vehicles. The Carpenter step assembly has upper, center, and lower treads. When the step assembly is in its fully retracted position, the bottom of the lower tread faces outwardly. However, even in its fully retracted position the Carpenter step assembly does add additional width to the side of the recreational vehicle to which it is attached. As is typical in such step assemblies, the carpenter step assembly is rather unsightly when in a fully folded position.
The limitations of the above-described steps of the prior art are typical of current designs. The present invention was developed to effectively address the issues of convenience, safe access to recreational vehicles, and the maintenance of an aesthetically please exterior surface, while fitting within the constraints imposed by space limitations such as ground clearance, vehicle width, and small mounting areas.
SUMMARY OF THE INVENTION
The present invention is directed towards a step assembly that is self-concealing and which can be mounted to a recreational vehicle. The step assembly contains a mountable housing that fully encloses multiple tread assemblies that are nestable within the housing and are extendible therefrom. Attachment arms are pivotally connected to the housing. A linear actuator is also attached to the mountable housing. One of the tread assemblies is directly coupled to the linear actuator for translationally extending and retracting this directly coupled tread assembly relative to the housing. The other tread assemblies are operatively associated with the linear actuator through the directly coupled tread assembly for rotationally extending and retracting the other tread assemblies in conjunction with the translational extending and retracting the directly coupled tread assembly. The lowermost of the tread assemblies has a tread lower surface and retraction of the tread assemblies causes this tread lower surface to substantially conceal the step assembly within the mountable housing.
In a preferred embodiment of the present invention, the step assembly further contains a slideway assembly, which has portions that are mounted to the directly coupled tread assembly and portions that are mounted to one of the other tread assemblies. The slideway assembly allows the directly coupled tread assembly to be slidable relative to the other connected tread assembly. The tread lower surface of the lowermost tread assembly is designed to provide or accept an aesthetically appealing outer surface to the housing of the step assembly when the step assembly is fully retracted.
A step assembly constructed in accordance with the present invention uses a simple and efficient construction design and operating technique. This step assembly meets the space limitation requirements associated with recreational vehicles and is fully nestable with a housing to form an aesthetically pleasing continuation of the vehicle outer surface when retracted.
REFERENCES:
patent: 2436961 (1948-03-01), Gabriel
patent: 2682671 (1954-07-01), Faure
patent: 3008533 (1961-11-01), Haberle
patent: 3330577 (1967-07-01), Mills
patent: 3408959 (1968-11-01), Cripe et al.
patent: 3743320 (1973-07-01), Clark
patent: 3807757 (1974-04-01), Carpenter et al.
patent: 3876230 (1975-04-01), Phillips
patent: 4020920 (1977-05-01), Abbott
patent: 4106790 (1978-08-01), Weiler
patent: 4108457 (1978-08-01), Garret
patent: 4110673 (1978-08-01), Nagy et al.
patent: 4116
Boyce Benjamin J.
Kunz James R.
Maccabee Malcolm M.
Christensen O'Connor Johnson & Kindness PLLC
Kwikee Products Co., Inc.
Shriver J. Allen
Swann J. J.
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