Step Ladder with Hinged Rungs Operable to Collapse on Multiple Axes

A ladder having rungs hingedly affixed at both terminal ends to a stringer, the ladder operable to collapse across a lateral or widthwise axis spanned by the rungs, the ladder having hingedly affixed stringers operable to collapse on a lengthwise or longitudinal axis. In some embodiments, a cylindrical tube receives the fully collapsed ladder for stowing and porting.

FIELD OF THE INVENTION

This invention relates to ladders and stepping implements and more particularly relates to foldable ladders for propping against upright structures.

BACKGROUND

Description of the Related Art

Stackable and foldable ladders are well-known in the art and operable in many cases to fold on a lengthwise axis to reduce the length of the ladder in half. Other common ladders telescope and are operable to retract to half, one third, or one fourth of their fully extracted length. Folding ladders offer the conveniences of being collapsible to a compact size for ease of transportation and storage and of being extendible to a variety of lengths and configurations for use as a self-supporting step ladder, a straight extension ladder or as a scaffold.

While these ladders in the art serve the utilitarian purpose of reducing length and improving portability and stowability, the folding ladders in the art remain cumbersome and do not fold or collapse across the widthwise axis spanned by the rungs and also the lengthwise axis spanned by the stringers. There are no ladders known in the art which full collapse across the rungs or which are capable to simultaneously collapsing across two axes to further improve stowability as would be desired by contractors, materialmen and other regularly moving and using ladders.

An object of the present invention is to provide a novel, foldable extension ladder which improves upon the abovenamed disadvantages wherein hinged rungs and joints interlock and collapse

In view of the foregoing, traditional folding ladders are nonoptimal and leave room for more optimal approaches to collapsing and tranporting.

SUMMARY

From the foregoing discussion, it should be apparent that a need exists for a dampening hinge system that suppresses periodic motions and abrasive wear on a hinge supporting an axial load. The present invention applies various components in novel ways to achieve this. In some embodiments, the connector arms for the hinge system may include bearings, smooth outer surfaces, and tight fittings to help suppress the periodic motions and abrasive wear. Additionally, adjustable mounting apertures provide flexibility during mounting, which reduces stress on the hinge system.

The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available apparatus. Accordingly, the present invention provides: a collapsible ladder comprising: two or more left side elongate stringers hingedly affixed at a midpoint of the collapsible ladder; two or more right side elongate stringers hingedly affixed at a midpoint of the collapsible ladder; a plurality of rungs having left terminal ends and right terminal ends, the rungs hingedly affixed at each terminal end to a stringer; wherein the ladder is operable to collapse on a longitudinal axis when the ladder is folded at a hinged midpoint; wherein the ladder is operable to collapse on a lateral axis when the left side stringers are moved longitudinally with respect to the right side stringers.

The collapsible ladder may further comprise one or more diagonal braces having a first terminal end hingedly affixed to a stringer and a second terminal end affixed to a rung.

The second terminal end of the diagonal brace may be adapted to travel on the rung. The second terminal end of the diagonal brace may travel on a pully mechanism. The collapsible ladder may further comprise a plurality of feet affixed to a terminal end of a stringer.

The collapsible ladder may further comprise a cylindrical tube adapted to receive the collapsible ladder in a fully-collapsed configuration. The collapsible ladder may further comprise a plurality of ridges adapted to improve nonslip function.

A second collapsible ladder is provided comprising: two or more left side elongate stringers hingedly affixed at a midpoint of the collapsible ladder; two or more right side elongate stringers hingedly affixed at a midpoint of the collapsible ladder; a plurality of rungs having left terminal ends and right terminal ends, the rungs hingedly affixed at each terminal end to a stringer; one or more diagonal braces having a first terminal end hingedly affixed to a stringer and a second terminal end affixed to a rung, the diagonal braces adapted to restrict axial motion of the rungs to less than 90 degrees; wherein the ladder is operable to collapse on a longitudinal axis when the ladder is folded at a hinged midpoint; wherein the ladder is operable to collapse on a lateral axis when the left side stringers are moved longitudinally with respect to the right side stringers.

The second terminal end of the diagonal brace may travel on a pully mechanism. A third collapsible ladder is provided comprising: a plurality of rungs having left terminal ends and right terminal ends, the rungs hingedly affixed at each terminal end to a stringer; wherein the ladder is operable to collapse on a lateral axis when the left side stringers are moved longitudinally with respect to the right side stringers.

DETAILED DESCRIPTION

The flow chart diagrams included herein are generally set forth as logical flow chart diagrams. As such, the depicted order and labeled steps are indicative of one embodiment of the presented method. Additionally, the format and symbols employed are provided to explain the logical steps of the method and are understood not to limit the scope of the method. Although various arrow types and line types may be employed in the flow chart diagrams, they are understood not to limit the scope of the corresponding method. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the method. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown.

FIGS. 1A-1Billustrate a forward side perspective view of fully collapsible ladder with hinged rungs100in accordance with the present invention.

A plurality of rung members104a-bare hingedly affixed to two or more elongate stringers102a-b. Each rung104comprises two terminal ends122a-b, with each terminal end122hingedly affixed to a stringer102.

Each of the rung members104comprises an elongate shaft, tube, beam, rod, or extruded polymeric or aluminum step or rung portion having a first end terminal end122aand second terminal end12b.

The stringers102may also be provided with apertures142which serve as hand holds for porting the ladder100.

The ladder100folds at hinges800affixed between adjacent stringers102. The hinge800is known to those of skill in the art, and further described below in relation toFIG. 8.

FIG. 1Ashown the ladder100in a fully collapsed configuration on both axes whileFIG. 1Bshows the ladder100is semi-collapsed configuration on a single axis. When the ladder100is in either a fully collapsed or semi-collapsed configuration, the ladder100is operable to collapse on its widthwise axis by moving the stringers102along one side of the rungs104along the longitudinal axis against the position of the stringers102on an opposing side of the ladder100. The ladder100is operable to collapse on both lengthwise and widthwise axes in a semi-collapsed or fully extended position.

FIG. 1Cillustrates a forward side perspective view of fully collapsible ladder140with hinged rungs in accordance with the present invention.

Shown in an open semi-collapsed position, the ladder140may also be folded open at the hinges800to configure as a fully-extended position depicted inFIG. 1D.

The ladder140is provided with a latching mechanism144. The latching mechanism144may include a simple hinge as known to those of skill in the art or a more complex hinge800as further described below.

FIG. 1Dillustrates a forward side perspective view of fully collapsible ladder with hinged rungs in accordance with the present invention.

In its fully extended position shown, the ladder160is operable to collapse on its widthwise, or lateral, axis by moving the stringer102in vertically opposed directions.

FIG. 2illustrates a forward side perspective view of fully collapsible ladder200with hinged rungs in accordance with the present invention.

The rungs104may be formed with ridges, molded or otherwise formed thereon, to increase track and stability of a user positioned on the rungs104. These ridges702act to provide a relatively non-slip surface on the steps. Other non-slip surfaces may be provided instead, as would be evident to a person skilled in the art.

FIG. 3illustrates a forward side perspective view of fully collapsible ladder300with hinged rungs in accordance with the present invention.

The rungs104operate to pivot about attachment point with the stringers102.

FIG. 4illustrates a rearward, exploded perspective view of fully collapsible ladder400with hinged rungs in accordance with the present invention.

In various embodiments, the ladder400comprises a diagonal brace402which positions beneath each rung104. The diagonal brace402is hingedly affixed at first terminal end404to a stringer102as shown. At a second terminal end406, the diagonal brace402affixes to one of a rung104and/or a pully or track within which the second terminal end406travels. The second terminal end406may affix to mounting bracket408which travels within a traveling mechanism such as the pully410shown.

The diagonal brace402is adapted to restrict motion of the rung104to which the diagonal brace402is connected from moving more than90degrees. In the shown embodiment, the rung104is restricted from axially rotating about its left terminal end in a clockwise direction when the rung104is in perpendicular orientation to the stringer102from a forward perspective.

The ladder400may comprise a plurality of polymeric feet412.

FIG. 5illustrates a side perspective view of fully collapsible ladder500with hinged rungs in accordance with the present invention. The ladder500is shown in a semi-collapsed configuration.

FIG. 6illustrates a side perspective view of fully collapsible ladder and carrying tube600with hinged rungs in accordance with the present invention.

The fully collapsed ladder100may insert into a tube602which allows the ladder100to be ported without unfolding during transport. The tube602may cylindrical and formed from polymeric or metal alloy.

If needed, a user can stack multiple fully collapsed ladders100one upon one another.

FIG. 7illustrates a forward perspective view of fully collapsible ladder700with hinged rungs in accordance with the present invention.

In various embodiments, the rungs104are hingedly affixed to pivot less than 90 degrees off a perpendicular orientation to the stringer102, with each rung102pivoting forward on a vertical (or longitudinal) axis at one terminal end and rearward on the vertical axis at the opposing vertical end.

FIG. 8illustrates a side perspective view of an interlocking hinge800for foldable ladders in accordance with the prior art.

A hinge800for foldable ladders known in the prior art comprises a first joint member10integrally formed with main discs13,14, a second joint member20integrally formed with a sub disc23, a locking device30having a button32, a connecting pin31, a coil spring34, a rectangular locking block33and a press locking control device60for controlling to latch or unlatch the locking device30. The first and second joint members10,20are combined together through a common axis of a center shaft50enabling them to rotate. The sub disc23of the second joint member20is inserted between a pair of parallel spaced main discs13,14of the first joint member10. The main discs13,14of the first joint member10have slot openings13a,13cfor inserting the locking device30. The first protruded arcuate stopper15is disposed at the inner surface of the main disc14. The second protruded arcuate stopper25is formed at the rear surface of the sub disc23of the second joint member20for matching with the first protruded arcuate stopper15of main disc14. A plurality of detents28is formed around periphery of the sub disc23. At one side of slot opening13cof the main disc14, a press locking control device60is installed for elastically actuating the device.

The hinge800may be integrated into a ladder100as shown, between two stringer102. In various configurations, the hinge800positions at a midway point on the ladder100between two stringers of identical length.