Removable stairway for an elevated platform and method   

This patent application is related to U.S. patent application Ser. No. 12/098,922 filed Apr. 7, 2008; Ser. No. 12/098,945 filed Apr. 7, 2008; and Ser. No. 12/098,955 filed April 7, 2008 which are herein incorporated by reference in their entirety for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to portable elevated platforms such as portable stages, risers, and the like.

2. Related Art

Portable platforms are often used as stages, risers, and the like. Such platforms are often formed of individual modules that are assembled at the site the platform is needed. The height of the platforms is often adjustable so that the platform can be positioned at a desired height. Sometimes the desired height is too high for a person to step up onto the platform. In these cases, steps or a stairs are is needed in order to gain access to the platform.

Some portable platform systems use stand alone steps or stairs that allow access to the platform. These stand alone steps or stairs are separate stairways that can be pushed next to the platform. With the ladder next to the platform, people can climb up the steps on the ladder to gain access to the elevated platform. Unfortunately, because these stair systems are supported independently from the platform they can move slightly with respect to the platform when people are climbing the stairs to enter or leave the platform. This independent movement can cause noise which may disrupt an event, as well as an uneasy feeling to people on the platform and/or the stairs.

Other portable platform systems attach a stair stringer to the platform. As used herein, a stair stringer is a plurality of steps attached to an inclined frame. In some cases, the stair stringer can be collapsible to more easily store and ship the stairs. When the stair stringer is attached to the platform, the steps can extend from the elevated platform to a support surface. Additionally, such stair stringers can include a sufficient number of steps to provide comfortable stairway access to the platform, and can automatically adjust in height with varying platform deck height.

Unfortunately, such stairways are often difficult to attach requiring fasteners such as screws, bolts or the like, which tend to slow down assembly of the portable platform. Additionally, many of these attachable stairways have a tendency to move in relation to the platform as users walk up the stairs to gain access to the platform. This movement can cause undesirable racking noise and give unsteady feelings to the users.

SUMMARY

The inventors of the present invention have recognized that it would be advantageous to develop a removable stairway for an elevated platform that can be easily secured to the platform. Additionally, the inventors of the present invention have recognized that it would be advantageous to develop a removable stairway for an elevated platform that can be attached to the platform without the use of separate fasteners. Additionally, the inventors of the present invention have recognized that it would be advantageous to develop a removable stairway for an elevated platform that can resist separate movement with respect to the platform when dynamically loaded as a user walks on the steps. Additionally, the inventors of the present invention have recognized that it would be advantageous to develop a stairway for an elevated platform that is adjustable in height in order to match the height of the elevated platform and that each step in the step system can automatically adjust in height to a similar height as the other steps in the stairway.

The invention provides for a removable stairway device configured for attachment to a platform. The removable stairway can include a platform having an elevated deck and a plurality of legs supporting the deck. A step or step system can be removably attachable to the platform and extendable from the platform in cantilever fashion. A gap can be formed between the step and the elevated deck of the platform when the removable step is attached to the platform. A lock plate can be pivotally coupled to the step. The lock plate can pivot to cover the gap between the step and the elevated deck. A flange can extend from the lock plate and engage a side of the platform when the step is attached to the platform and the lock plate is pivoted to cover the gap.

The present invention also provides a method for coupling a removable stairway to a platform including coupling a removable step to an elevated deck of the platform such that the step extends away from the deck in cantilever fashion. A lock plate can be pivotally coupled to the step to lock a gap between the step and the elevated deck such that a flange extending from the lock plate frictionally engages a side of the platform to safely lock the stairs in place when the step is attached to the platform and the lock plate is pivoted to cover the gap.

Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a removable stairway coupled to an elevated platform in accordance with an embodiment of the present invention;

FIG. 2 is a side view of a removable step of the removable stairway of FIG. 1, shown in a coupleable orientation with respect to the elevated platform of FIG. 1;

FIG. 3 is a side view of a removable step of the removable stairway of FIG. 1, shown in a coupleable orientation with respect to the elevated platform of FIG. 1;

FIG. 4 is a side view of a removable step of the removable stairway of FIG. 1, shown in a coupled orientation with respect to the elevated platform of FIG. 1;

FIG. 5 is a side view of a removable step of the removable stairway of FIG. 1, shown in a coupled orientation with respect to the elevated platform of FIG. 1 and also showing a lock plate locking a gap between the removable step and the elevated platform in accordance with an embodiment of the present invention;

FIG. 6 is a fragmentary side view of the removable step of FIG. 2 coupled to the platform of FIG. 1;

FIG. 7 is a fragmentary perspective view of the removable step of FIG. 2 shown with a pivotable lock plate hingedly coupled to the removable step;

FIG. 8 is a fragmentary perspective view of the removable step of FIG. 2 shown with the lock plate of FIG. 7 partially installed into a hinge slot; and

FIG. 9 is a fragmentary perspective view of the removable step and lock plate of FIG. 8 shown with the lock plate partially installed into a hinge slot.

DETAILED DESCRIPTION

Reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles of the inventions as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention.

The embodiments of the present invention described herein provide generally for a removable stairway for an elevated platform such as a deck, riser, stage, and the like. The removable stairway can include a step removably coupleable to the elevated deck of the platform. A plurality of lower steps can extend downward from the removable step to a ground surface to form the stairway. The removable step can include a cover or lock plate pivotally coupled to the step and pivotal to cover a gap between the step and the elevated platform and lock the step against the platform. The lock plate can have a flange extending substantially orthogonally from the lock plate. The flange can be positioned on the lock plate so as to engage a side of the platform when the removable step is coupled to the elevated deck and the lock plate is pivoted to cover the gap. The flange can frictionally engage the side of the platform in an interference fit such that an applied force is required to set or release the lock plate from the locked position. Advantageously, the removable step can be easily attached to the platform without any separate fasteners to secure the step to the platform. Additionally, the lock plate and flange can form a linkage between the removable step and the side of the platform that advantageously resists movement of the removable step with respect to the platform due to dynamic loading on the removable step as users climb the stairway.

As illustrated in FIGS. 1-9, a removable stairway device, indicated generally at 10, attachable to an elevated platform, indicated generally at 20, is shown in accordance with the present invention for providing access to the elevated platform. The platform 20 can include an upper, elevated deck 22 and a plurality of legs (not shown) that support the deck. The removable stairway device 10 can include a removable step 50 coupleable to the platform 20, and a lock plate 70 to lock a gap 90 between the removable step 50 and the platform 20.

With respect to the platform 20, the plurality of legs can be adjustable in length in order to adjust the height of the elevated deck 22. In one aspect the platform 20 can be a portable platform such as a portable stage or portable risers as described in U.S. patent application Ser. No. 12/098,945 filed on Apr. 7, 2008, which is herein incorporated by reference in it\'s entirety for all purposes.

With respect to the removable stairway 10, the removable step 50 can be removably attachable to the platform 20, and extendable from the platform in cantilever fashion. The removable step 50 can be sized and shaped to allow users to stand or walk on the step as they are climbing the stairway 10. The removable step 50 can be positioned at a spaced apart distance from the side 26 of the platform 20 in order to form a gap 90 between the step 50 and the elevated deck 22 of the platform 20.

The removable step 50 can include a bracket 52 that can fit within a groove or slot 28 disposed in a side 26 of the platform 20. The bracket 52 can be inserted into the slot 28 by orienting the step in a vertical orientation, as shown in FIG. 2, and sliding an upwardly extending lip 54 on the bracket 52 into the slot 28. The step 50 and bracket 52 can then be rotated, as shown in FIG. 3 to position the step 50 in a substantially horizontal position, as shown in FIG. 4, with the step 50 extending away from the platform 20 in cantilever fashion. The upwardly extending lip 54 on the bracket 52 can engage a downwardly extending lip 30 of the slot 28 on the platform 20 when the bracket 52 is disposed in the slot 28.

In one aspect, the bracket 52 can be separate from the step 50 and can support or carry the removable step, as shown in the FIGs. In another aspect (not shown), the bracket 52 can be integrally formed with the removable step 50. In either case, the bracket 52 and removable step 50 can be configured such that downward loads, indicated at 100, that may be applied to the removable step 50 can push the upwardly extending lip 54 of the bracket 52 against the downwardly extending lip 30 on the slot 28 of the platform 20, as shown in FIG. 5. Thus, in use, when a person places weight on the removable step 10, the load 100 resulting from the weight of the person can push the removable step 50 downward. This downward force 100 can push the upwardly extending lip 54 upward and outward so that the upwardly extending lip can contact the top 32 of the slot 28 and the downwardly extending lip 30 of the slot. The contact between the upwardly extending bracket lip 54 and the downwardly extending slot lip 30 can restrict the bracket 20 from moving out of the slot 28 when a downward load is placed on the removable step 50.

Additionally, a stair stringer, indicated generally at 110, can be coupled to the removable step 50 and can extend downward from the removable step 50 to a ground surface. The stair stringer 110 can include a framework 112 that can support a plurality of sequential steps 114 with respect to the removable step 50. The framework 112 can automatically adjust each step to be parallel to one another. Additionally, the framework 112 can automatically adjust each step 114 to have a substantially equal height as the other steps 114 in the stair stringer 110. In this way, the framework 112 can automatically adjust the steps 114 to match the height of the elevated platform 20 to which the stair stringer 110 is attached. Together the removable step 50, the framework 112, and the plurality of lower steps 114 can form the stairway 10.

Turning to FIGS. 6-9, the lock plate 70 can be pivotally coupled to the removable step 50. The lock plate 70 can be pivotal to cover the gap 90 between the removable step 50 and the elevated deck 22, as shown by dashed lines in FIGS. 1 and 6. The lock plate 70 can be formed of a metal or rigid plastic material that can have sufficient strength to support dynamic loads from users walking between the step 50 and the elevated deck 22. For example, in one aspect, the lock plate 70 can be formed of aluminum and can be extruded to a desired size. In another aspect, the lock plate 70 can be formed of polyurethane material and molded to the desired size and shape. Other materials having sufficient strength, as known in the art, can also be used to form the lock plate 70.

The lock plate 70 can be a substantially flat plate coupled to the removable step 50 by a hinge indicated generally at 80. The hinge 80 can be formed by a cylindrically shaped pivot edge 72 of the lock plate 70. The cylindrically shaped edge 72 can be disposed in a mating cylindrically shaped slot 60 on the removable step 50. The cylindrically shaped slot 60 can have an opening, indicated generally at 62, extending the length of the cylindrically shaped slot 60 through which the cylindrically shaped edge 72 of the lock plate 70 can extend and pivot with respect to the removable step 50. The hinge 80 can extend along and entire length of the removable step 50. The hinge 80 can be positioned so that when the lock plate 70 is pivoted to cover the gap 90, the lock plate 70 can be substantially co-planar with a top surface 58 of the removable step 50 and a top surface of the elevated deck 38, as best seen in FIG. 6.

The lock plate 70 can include a flange 74 that can extend from the lock plate 70 at an oblique angle with respect to the lock plate. In one aspect, the flange 74 can extend away from the lock plate 70 in a direction that is substantially perpendicular to the lock plate. The flange 74 can be positioned on the lock plate 70 at a location that allows the flange 74 to engage the side 26 of the platform 20 when the removable step 50 is attached to the platform and the lock plate 70 is pivoted to cover the gap 90. The flange 74 can be slightly flexible in order to conform to the position of the side 26 of the platform 20 with respect to the lock plate 70. In this way, the flange 70 can be positioned on the lock plate 20 so as to form an interference fit with the side 26 of the platform 20 when the lock plate 70 is pivoted to cover the gap 90 and the flange 74 frictionally engages the side of the platform.

The flange 74 can also include a beveled end 76. The beveled end 76 can extend towards the pivot end 72 of the lock plate 70. The beveled end 76 can be sized and shaped to engage the side wall 26 of the platform 20. The beveled end 76 can guide the flange 74 along the side 26 of the platform 20 as the lock plate 70 is pivoted to cover the gap 90. It will be appreciated that a straight or butt end on the flange could catch or hang up on the side of the platform because in order to achieve the interference fit between the flange 74 and the side 26 of the platform 20, the position of the flange 74 might slightly overlap the position of the side of the platform. Thus, in order to allow the flange 74 to engage and slide along the side 26 of the platform 20, the beveled end 76 can first contact the side of the platform and flex or bend the flange to conform to the position of the side of the platform.

Advantageously, the interference fit between the flange 74 and the side 26 of the platform 20 can restrict inadvertent movement of the lock plate 70 during loading of the removable step 50. Additionally, the lock plate 70 and flange 74 can maintain the position of the removable step 50 with respect to the platform 20 when the lock plate 70 is pivoted to cover the gap 90. Consequently, the interference fit between the flange 70 and the side 26 of the platform 20 can restrict movement of the removable step 50 with respect to the platform 20. In this way, the lock plate 70 and flange 74 can act as a linkage mechanism that can lock the removable step 50 into place with respect to the platform 20. Thus, advantageously, the flange 74 can resist rotation of the removable step 50 due to upward and downward forces applied to the removable step 50 by users of the stairway 10 when the lock plate 70 is pivoted to cover the gap 90 and the flange 74 engages the side 26 of the platform 20.

The present invention also provides a method for coupling a removable stairway to a platform including coupling a removable step to an elevated deck of the platform such that the step extends away from the deck in cantilever fashion. A lock plate can be pivotally coupled to the step to lock a gap between the step and the elevated deck such that a flange extending from the lock plate frictionally engages a side of the platform when the step is attached to the platform and the lock plate is pivoted to cover the gap.

The method can also include positioning a plurality of lower steps coupled to the removable step below the removable step to form a stairway from a ground surface to the elevated deck.

Additionally, the method can also include pivoting the lock plate to an unengaged position where the flange is free from contact with the side of the platform to uncover the gap. The removable step can then be removed from the elevated deck.

It is to be understood that the above-referenced arrangements are only illustrative of the application for the principles of the present invention. Numerous modifications and alternative arrangements can be devised without departing from the spirit and scope of the present invention. While the present invention has been shown in the drawings and fully described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiment(s) of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications can be made without departing from the principles and concepts of the invention as set forth herein.