Fire escape – ladder – or scaffold – Unitary foldable – rigid scaffold or ladder – Collapsible ladder
Reexamination Certificate
1999-09-16
2002-02-19
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Unitary foldable, rigid scaffold or ladder
Collapsible ladder
C182S159000
Reexamination Certificate
active
06347687
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to collapsible step or utility ladders, and more particularly to a collapsible step ladder that is compact and that requires minimal storage space.
A drawback of existing step ladders is that they are typically bulky and consequently require large storage spaces or separate storage facilities. The size and configuration of existing collapsible step ladders is not as important in places where storage is readily available, such as work sites, warehouses, factories, etc. However, in some instances storage facilities may be limited by the physical construction of those facilities or by the costs of maintaining large storage facilities.
Additionally, storage space is even more at a premium in typical city living units, such as condominiums and apartments, or in college dormitory rooms. Moreover, a user may want to use other areas as storage space, for example the trunk of a car, a small closet, kitchen, hamper, underneath a bed or sofa, etc., but is limited by the configuration of existing collapsible step ladders. Existing collapsible step ladders are typically large and bulky and do not allow such uses. For the foregoing reasons, there is a need for a simple collapsible step ladder that is slim and compact that can be efficiently, easily and practically stored in space starved locations, such as a person's apartment, condominium or dormitory room or small storage areas, when not in use.
SUMMARY OF THE INVENTION
Briefly, the present invention is a compact collapsible step ladder assembly that is comprised of a novel configuration of components such that the overall closed ladder thickness or overall dimension of the collapsed ladder does not exceed the combined thickness of the front and rear ladder legs. The compact collapsible step ladder addresses the need for a step ladder design with minimal storage space requirements. The new compact collapsible step ladder is durable, convenient and may be stored in a myriad of space limited areas.
In the preferred embodiment of the present invention, the compact collapsible step ladder assembly operates between an open position and a closed position. The step ladder comprises a first and second ladder support, a step, at least one rung and at least one connecting member. The first ladder support comprises a first front and a first rear leg with the first front and first rear legs being pivotally connected and each having a predetermined thickness. Further, the first front and first rear legs form an acute angle in the ladder open position and are substantially parallel to each other in the ladder closed position. Moreover, the first rear ladder leg further comprise a first channel guide and a first guide stopper. The second ladder support comprises a second front and a second rear leg with the second front and second rear legs being pivotally connected and each having a predetermined thickness. The second front and second rear legs also form an acute angle in the ladder open position and are substantially parallel to each other in the ladder closed position. The second rear ladder leg further comprises a second channel guide and a second guide stopper. The step ladder has a step that is adapted for pivotal movement with respect to the front ladder legs. The step further has a rear step portion, a first side step portion with a first step connector, a second side step portion with a second step connector. Extending from the step is a first and second peg. The first peg extends from a rear end portion of the step and slidably engages the first channel guide. Further, in the ladder open position, the first peg rests against the first guide stopper to maintain the step in a substantially horizontal orientation. The second peg extends from an opposing rear end portion of the step, the second peg slidably engages the second channel guide. Again, in the ladder open position, the second peg rests against the second guide stopper to maintain the step in a substantially horizontal orientation. The step ladder also has at least one rung. In the preferred embodiment of the invention, there is one rung. In another version of the present invention, the step ladder has two rungs. The ladder rung or rungs are adapted for pivotal movement with respect to the front ladder legs and have a first side rung portion with a first rung connector and a second side rung portion with a second rung connector. The step ladder further has at least one connecting member or connecting rod. In the preferred embodiment, a pair of connecting rods, or connecting members, couple the first step connector to the first rung connector and the second step connector to the second rung connector. The pair of connecting rods synchronize the movement of the ladder rung with the step as the ladder assumes the open and closed positions. In the two rung version of the step ladder, the connecting rods simultaneously couple the step and the two rungs to synchronize their movement. In either the one or two rung versions of the ladder, the compact collapsible ladder, in the closed position, has a collapsed ladder thickness that does not exceed the combined thickness of the front and rear ladder legs.
The embodiments of the invention may additionally include front cross-braces for added support, strength and stability of the ladder. The preferred embodiment of the invention includes a front step portion, a step brace, a front rung portion and a rung brace. The step brace extends between the front legs and cooperatively engages the front step portion for pivotal movement of the step with respect to the first and second front legs. The rung brace extends between the front legs and cooperatively engages the front rung portion for pivotal movement of the rung with respect to the first and second front legs. Additionally, the step ladder may add at least one rear cross-brace between the first and second rear legs for greater support, strength and stability.
In another embodiment of the present invention, a compact collapsible step ladder comprises a front leg pair and a rear leg pair pivotally connected to the front leg pair. The pivotal connection permits movement of the rear leg pair in a collapsing direction from an open position where respective ends of the front and rear leg pairs are disposed in a distal relationship, and where said respective ends are disposed in a proximal relationship in a closed position. The front leg pair has a first maximum thickness measured in the collapsing direction and the rear leg pair has a second maximum thickness measured in the collapsing direction. The step ladder has a step that cooperates with the front leg pair and has a step width that exceeds the first and second maximum thicknesses. The step ladder also has at least one rung that cooperates with the front leg pair and has a rung width that exceeds the first and second maximum thicknesses. The step ladder includes a means for pivoting the step and at least one rung relative to the front leg pair as the rear leg pair is moved from the open position to the closed position. The step ladder, in the closed position, has a maximum overall thickness, measured in the collapsing direction, that is less than the width of the step or at least one rung. Furthermore, the maximum overall thickness of the ladder in the closed position does not substantially exceed the sum of the first and second maximum thickness. Additionally, the means for pivoting the step and rung may include a step pivot connection between the step and a step brace extending between the front leg pair, and a rung pivot connection between the rung and a rung brace extending between the front leg pair. The step pivot connection also has a brace pivot surface formed on the step brace and a step recess on the step, the step recess being shaped complementarily to the brace pivot surface, and the rung pivot connection also having a rung pivot surface formed on the rung brace and a rung recess on the rung, where the rung recess is shaped complementarily to the rung pivot surface.
An object of the
Banner & Witcoff , Ltd.
PT Indal Aluminum Industry TBK.
Stodola Daniel P.
Thompson Hugh B.
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