Staircase protective step cover and or replacement step

A protective step cover that is both functional, decorative, and the versatility of protecting and or replacing the steps, rectangular in configuration, the top having a horizontal surface with grooves formed into the plastic for traction, the front and rear having a flat vertical surface, the bottom having a flat horizontal surface on each side of the parallel radius drip edges for eliminating moisture, with an open center section for detachably attached to said steps; and brackets, rectangular in configuration, the top having a flat horizontal supporting surface, the front and rear having a flat vertical surface, the bottom having a flat horizontal surface on each side of an open center section for allowing access, the sides having holes for attaching bolts through bracket to the supporting structure, for providing brackets for the protective step cover detachably attached to said brackets to replace the steps in their entirety.

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Description
FIELD OF THE INVENTION

This invention relates to exterior staircase steps, specifically to such steps which are used on two, three, and four stories, apartment houses, condominiums, industrial, and commercial buildings.

BACKGROUND OF THE INVENTION

This invention relates to an exterior staircase that comprises, of a supporting structure, a flight of stairs, and a handrail. This type of staircase are commonly used on two, three and four stories, apartment houses, condominiums, industrial and commercial buildings, and are still the most commonly used today. The recurring problem that exists year after year is the deterioration of the concrete pre-cast steps and its attaching metal plates deteriorating steps are often left in the staircase until the surface is deteriorated, cracking, and steel reinforcement is showing, and becomes a dangerous liability. This is often the case due to the cost of replacing of just one step; it has become the trend to wait until more steps need replacing to make it more cost effective. Initially, concrete pre-cast steps with metal plates cast into the underneath of the step at both ends that are electrically weld to the supporting structure and the metal pan steps that comprise of a metal pan electrically welded to the supporting structure and then concrete is poured into the pan to complete the step. These type of steps deteriorate over a very short time and are inherently unstable, as a result of impact, ultraviolet rays, freeze and thaw, salt and other harmful chemicals, and are difficult to replace, to one that is not skilled in the profession of structural fabrication and electrical welding of metals or one skilled in concrete construction. These types of staircases are manufactured at the time of the initial construction of the building, and access is not a problem, at once the construction process is complete, access to the underneath of the staircase can be extremely difficult. The steps are removed from underneath by either grinding away the electrically welded plates with an abrasive wheel or by the use of an acetylene torch to cut away the electrically welded plates, that are attached to the supporting structure, at this time the pre-cast step can be removed and a new concrete pre-cast step can be lifted into position, electrically welding plates to the supporting structure or electrically welding a new metal pan into position and re-pouring the concrete into the pan to complete the step. These steps are prohibitively expensive to the consumer. Concrete pre-cast and metal pan steps are elevated and cannot sustain a hard impact, the result of a hard impact fractures the concrete surface allowing moisture to enter in the fractured concrete, deteriorating the concrete and reinforcement, also if it fractures through to the underneath of the step, the moisture will deteriorate the attaching metal plates that support the step to the supporting structure. This results in failure of the step and becomes detached from the supporting structure. These type of staircase steps cannot eliminate the moisture collecting underneath the steps allowing the moisture to hang underneath the step deteriorating the step until the moisture can evaporate into the air or on a wintry cold evening it will eventually become frozen, turning into ice, expanding, causing the step fracture to separate, weakening the step, reinforcement and its attaching plates. Steps that use a metal pan for support do not have reinforced concrete and rely on the metal pan for its only support, once the pan is deteriorated the concrete step falls through the pan onto the ground. Once summer approaches, the steps then contract adding opposite stress to the step, plates, pan, and supporting structure, from the constant expansion and contraction, eventually deteriorating the entire supporting structure. This will result in a total replacement of the staircase.

Initially, exterior staircases with concrete pre-cast and metal pan steps with concrete poured into them, have performed fairly well in the warmer climates, although, impact, a ultraviolet rays, and moisture, eventually takes its toll. Exterior staircase steps, that have to withstand vigorous winter months have a much higher rate of deterioration, once the concrete is fractured, deteriorating step and metal attaching plates, since the steps were rather permanent nature, the buildings maintenance crews would attempt to caulk the fractures with silicones, epoxy, paint, plaster, which is not effective.

Exterior staircases, attempting to repair the steps, have very shortcomings. Repairs that are attempted using silicones, epoxies, and plasters are repaired over the fractures, and deteriorated areas, making the surfaces uneven and difficult to walk up and down the staircase, and a high risk of liability. Silicones, epoxies, plasters, paint, have the tendency to crack, peel, curl upward, and in a very short time, allowing moisture to re-enter. Heretofore no device has been created to fulfill the need for protecting the original steps, and the versatility of protecting and or replacing the step with the capability of eliminating moisture, resistant to impact, ultraviolet rays, expansion and contraction, salt and other harmful chemicals.

It is therefore an object of the invention to provide a protective step cover for protecting staircase steps.

It is another object of the invention to provide a protective step cover having an anti-slip surface.

It is another object of the invention to provide brackets for the protective step cover to replace the steps in their entirety.

It is another object of the invention to provide a protective step cover with an open center section for attachment to the steps and or brackets that is detachable without the use of tools.

It is another object of the invention to provide a protective step cover bottom having parallel radius drip edges that will eliminate moisture.

It is another object of the invention to provide a protective step cover that is resistant to impact, ultraviolet rays, expansion and contraction, salt and other harmful chemicals.

It is a further object of the invention to provide a protective step cover that is both functional, decorative, having a variety of colors.

It is a further object of the invention to provide a bracket that is resistant to corrosion.

It is a further object of the invention to provide a bracket with an open center section for access and holes at opposite ends to bolt brackets to supporting structure.

SUMMARY OF THE INVENTION

A protective step cover that is both functional, decorative, and the versatility of protecting and or replacing the steps, rectangular in configuration, all views having four right angles, the top having a horizontal surface having grooves formed into the plastic for traction, the front and rear having a flat vertical surface, the bottom having a flat horizontal surface on each side of the parallel radius drip edges for eliminating moisture, with an open center section for detachably attached to said steps; and brackets, rectangular in configuration all views having four right angles, the top having a flat horizontal supporting surface, the front and rear having a flat vertical surface, the bottom having a flat horizontal surface on each side of an open center section for allowing access, the sides having a flat vertical surface and holes for attaching bolts through bracket to the supporting structure, for providing brackets for the protective step cover detachably attached to said brackets to replace the steps in their entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent, detailed description, in which:

FIG. 1 is a perspective view of a typical staircase, a flight of steps, a supporting structure and a handrail; showing a flight of steps and a supporting structure in accordance with the present invention of the protective step cover;

FIG. 2 is a perspective view of the preferred embodiment of the present invention of the protective step cover, rectangular in configuration, all views having four right angles, showing a top view having a horizontal surface with its length greater than its width, with horizontal grooves having been formed into the plastic for traction, showing a front view having a flat vertical surface with its length greater than its height, a mirror image of the rear; and showing a side view with horizontal parallel radius drip edges a mirror image of the other side, shown attached to the steps in FIG. 1 in accordance with one embodiment;

FIG. 3 is a perspective view of the present invention of the protective step cover shown in FIG. 2 showing a bottom view having a flat horizontal surface on each side of the drip edges, with an open center section for attachment, detachably, attached to said steps shown in FIG. 1 and a detailed view of the parallel radius drip edges for eliminating moister;

FIG. 4 is a side perspective view of the present invention of the protective step cover shown in FIGS. 2, 3, detachably, attached to brackets, for replacing the step in their entirety, shown in FIG. 1 in accordance with another embodiment;

FIG. 5 is a perspective view of the bracket shown in FIG. 4 rectangular in configuration, all views having four right angles, showing a top view having a flat horizontal supporting surface with its length greater than its width, showing a front view having a flat vertical surface with its length greater than its height, a mirror image of the rear; and showing a side view having a flat vertical surface with its width greater than its height and holes, a mirror image of the other side for attaching bolts through bracket and supporting structure shown in FIG. 1 for attachment of the protective step cover, shown in FIG. 4; and

FIG. 6 is a perspective view of the bracket shown in FIG. 4, 5 showing a bottom view having a flat horizontal surface with its length greater than its width on each side of an open center section allowing access to bolt bracket to supporting structure.

For purposes of clarity and brevity, like elements and components will bear the same designations and numbering throughout the Figures.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a perspective view of a typical staircase 10, a flight of steps 14, a supporting structure 12 and a handrail; showing a flight of steps 14 and a supporting structure 12 in accordance with the present invention of the protective step cover.

FIG. 2 is a perspective view of the preferred embodiment of the present invention of the protective step cover, rectangular in configuration, all views having four right angles, showing a top view having a horizontal surface with its length greater than its width, with horizontal grooves having been formed into the plastic for traction, showing a front view having a flat vertical surface with its length greater than its height, a mirror image of the rear; and showing a side view with horizontal parallel radius drip edges a mirror image of the other side, shown attached to the steps in FIG. 1 in accordance with one embodiment.

FIG. 3 is a perspective view of the present invention of the protective step cover shown in FIG. 2 showing a bottom view having a flat horizontal surface on each side of the drip edges, with an open center section for attachment, detachably, attached to said steps shown in FIG. 1 and a detailed view of the parallel radius drip edges for eliminating moister.

Referring to FIGS. 2, 3, in accordance with one embodiment of the protective step cover maybe fabricated of a high strength plastic which can be repeatedly spread apart by spreading outwardly of the drip edges for attachment and maintaining its stability, the plastic also has a resistance to; impact, ultraviolet rays, expansion and contraction, salt and other harmful chemicals, such as ABS, acrylonitrile butadiene and styrene; CPVC, chlorinated polyvinyl chloride; PVC poly-vinyl chloride; HDPE high density polyethylene; LDPE, low density polyethylene polypropylene; PVDF, polyvinylidene chloride; and other composites are available from plastic chemical companies. However, the protective step cover can consist of any other non metallic or metallic materials, such as nylon, rubber, various impregnated or laminated fibrous materials, various plasticized materials, metals, alloys, etc. Moreover, the protective step cover in the preferred embodiment rectangular in configuration, can also be shaped as a circle, semi-circle, square, polygon, or any other geometrical shape deemed to be aesthetically pleasing to the user. The protective step cover top 16, having horizontal grooves for traction, it can also be a grid, squares, circles, diamonds, and abrasives such as, silica, glass-bead, or any other suitable shapes, patterns and abrasives that provide traction. The horizontal protective step cover top 16 is thermally molded to the flat vertical protective step cover front and rear 18, the front and rear can be angled, have decorative patterns such as rosettes, longitudinal groves, diamonds, squares, circles, or any other shapes and patterns deemed to be aesthetically pleasing to the user. The protective step cover front and rear 18 are thermally molded to the horizontal protective step cover bottom 20 with an open center section, which allows the protective step cover bottom 20 and the protective step cover front and rear 18 to flex enabling attachment to the steps and or the brackets, the attachment can also be hinges, clasp, pressed, bolts, gluing, welding, or any other fastening in a manner well known to those skilled in the art. The protective step cover front and rear 18 is thermally molded to the protective step cover bottom 20 having parallel radius drip edges, for eliminating moister, the parallel radius drip edges, can be positioned on the lower front, rear, sides, middle, and can be any shape such as an L-shape, triangular points, radiuses or any other locations and shapes that will eliminate moister. The protective step cover can be formed by extrusion of liquid plastic, thermo vacuum forming, pressure forming, metal extrusion, casting molds, machining, bending, or in a manner well known to those skilled in fabrication.

FIG. 4 is a side perspective view of the present invention of the protective step cover shown in FIGS. 2, 3 detachably, attached to brackets, for replacing the step in their entirety, shown in FIG. 1 in accordance with another embodiment.

FIG. 5 is a perspective view of the bracket shown in FIG. 4 rectangular in configuration, all views having four right angles, showing the bracket top 22 having a flat horizontal supporting surface with its length greater than its width, showing a bracket front and rear 26 having a flat vertical surface with its length greater than its height, and showing a bracket sides 24 having a flat vertical surface with its width greater than its height and holes, a mirror image of the other side for attaching bolts through bracket and supporting structure 12 shown in FIG. 1 for attachment of the protective step cover, shown in FIG. 4.

FIG. 6 is a perspective view of the bracket shown in FIGS. 4, 5 showing a bracket bottom 28 having a flat horizontal surface with its length greater than its width on each side of an open center section allowing access to bolt bracket to supporting structure 12.

Referring to FIGS. 4, 5, 6 another embodiment, the protective step cover and brackets, the bracket is rectangular in configuration, the bracket top 22 having a flat horizontal supporting surface, structurally molded to the bracket front and rear 26 having a flat vertical surface, providing a frame, once attached to the supporting structure 12 to keep the protective step cover secure. The bracket front and rear 26 are structurally molded to the bracket sides 24 having holes for attaching bracket to supporting structure 12, the bracket front and rear 26 are structurally molded to the bracket bottom 28 having a flat horizontal surface for attaching of the protective step cover bottom 20 and an open center section, for providing access to holes in the bracket sides 24 for attaching bolts through the bracket and supporting structure 12. The bracket can also be attached by hinges, clasp, glue, welding or any other fastening in a manner well known to those skilled in the art. The bracket maybe fabricated of a galvanized metal and structurally molded into a rectangular shape with the bracket bottom 28 open for access, however, the bracket can consist of any other non metallic or metallic materials such as, structural plastic, reinforced rubber various impregnated or laminated fibrous materials, various plasticized materials, metals, alloys, or any other suitable materials that provide support. Moreover the bracket rectangular in configuration, can also be, round, square, triangular, or any other geometrical shape deemed for providing support, in a manner well known to those skilled in fabrication.

Operation

FIG. 1 is to show a typical staircase 10 for providing a flight of steps 14 and a supporting structure 12 in accordance with the present invention of the protective step cover and brackets.

FIGS. 2, 3, 4 the manner of using the protective step cover; the protective step cover bottom 20, shows horizontal parallel radius drip edges with an open center section, by grasping each drip edge and lightly pulling the drip edges away from each other until each drip edge clears the front and rear of the step and or the front and rear of the brackets, and placing the protective step cover over the step and or brackets, once the drip edges clear the bottom of the step and or brackets, release the drip edges, the drip edges then will retract underneath the step and or brackets, gripping the underneath of the step and or brackets, tightly securing the protective step cover, the protective step cover front and rear 18 are slightly pitched inward and the protective step cover bottom 20 is also slightly pitched upward, this will keep a constant pressure of all of the protective step cover inside planes, tightly secured to the steps and or brackets. Reversing this process will easily detach the protective step cover from the step and or brackets.

FIGS. 5,6 the manner of using the brackets, the brackets will replace the step and will provide the support for the protective step cover, by removing the existing step and attaching the bracket sides 24 to each supporting structure 12, this will provide a frame for the protective step cover top 16, the protective step cover front and rear 18 and the protective step cover bottom 20, and will provide the structural support and attachment of the protective step cover, explained in operation above, FIGS. 2,3, and 4.

Advantages

From the description above, a number of advantages of some embodiments of my protective step cover become evident:

(a) The staircases with pre-cast concrete steps and the metal pan steps with concrete poured into them are astronomically expensive to construct and even more expensive to replace, a number of these steps are replaced year after year until all of them have been replaced, and then starting back to the first ones all over again, this is a vicious cycle. The protective step cover can be attached to deteriorating steps as long as they are structurally intact and will eliminate the continuance of deterioration, the steps that have become unstable will need to be replaced with the protective step cover and brackets, the steps that have been covered and replaced shows no evidence of the steps that have been covered to those that have been replaced. The supporting structure 12 is painted or sometimes powder-coated and needs touch up time after time by tenants moving in and out scratching the surface, this requires masking of the steps for eliminating paint from dripping or splashing onto the steps, or if one chooses to change the color of the supporting structure 12, in just a few seconds the protective step cover can be removed and stacked to the side, once the job is complete the protective step cover then can be re-attached in just a few seconds, this can save days even weeks of the jobs completion. The protective step cover and brackets will never have to be replaced unless the protective step cover has been malicious damaged. The protective step cover and brackets can save weeks on construction of a new staircase 10, the supporting structure 12 is fabricated and painted and then delivered to the job site, then erected with a crane or other equipment that can lift heavy objects, this can be extremely expensive and access can be a problem, the supporting structure 12 is engineered to handle the weight of the steps, people, furniture etc, the pre-cast steps are welded into position or the pans are welded into position and then all of the pans are filled with concrete, again having access for the concrete truck to pour out the steps, if there is no access then the concrete will have to be pumped in, or brought in with the use of wheel barrels, and shoveled into the pans, this could take several days. An extra charge is tacked on every order that is less than six yards of concrete and truck time is charged while the truck is on the job, this can get astronomically expensive. Once the pre-cast concrete or the metal pan steps are finished, the staircase 10 is all scratched up from welding in the steps and or pans and pouring of the concrete into the pans, now the touch up begins.

(b) With the use of the protective step cover, will provide protection of the existing steps, and eliminate the continuance of deterioration; The protective step cover and brackets will replace the unstable steps, with no evidence of the steps that have been covered, to the steps that have been replaced.

(c) Providing a protective step cover that is easily attached and de-attached, to allow painting of the supporting structure 12, with no need to mask the existing steps, saving an astronomical amount of time and money to the user.

(d) With the use of the protective step cover and brackets, in constructing a new staircase 10, the supporting structure 12 can be reduced in size due to the fact of that the protective step cover and brackets are extremely light and strong, this allows the supporting structures reduced size to be carried into the job site with out the use of expensive machinery, it can also be painted in the fabrication shop or painted on the job site, once the supporting structure 12 is attached to the building, the pre-drilled supporting structure sides, are now ready for the brackets to be bolted into place and the protective step cover attached. Theretofore, access is not a problem, no need for expensive equipment, no need for concrete, or a concrete pump and or wheelbarrows, and no damage to the supporting structure 12, as a result of the installation of the supporting structure 12 or installation of the steps, and no touch up or repainting of the supporting structure 12 will be needed. This saves time and money to the fabrication shop and the user.

(e) With the use of the protective step cover and brackets, a building that is under remolding, and the entrance has been moved, this will allow the staircase 10 to be moved if the staircase 10 has the protective step cover and brackets installed, where as the existing staircase 10 permanent in nature is usually scraped, and a new staircase 10 is constructed in the new location. A building that is scheduled for demolition, the existing staircase 10 is demolished along with the building, if the protective step cover and brackets are used in just a few hours the staircase 10 can be disassembled and moved to a new job site and re-assembled.

Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.

Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims.

Claims

1. A staircase protective step cover and or replacement step for protecting the concrete steps from deteriorating and versatility of protecting and or replacing the concrete steps in their entirety, comprising:

means for providing a stationary frame;
means for providing steps, rigidly connected to said means for providing a stationary frame;
means for providing traction;
means for providing flexibility and stability, thermally molded to said means for providing traction;
means for providing attachment to steps and to eliminating moisture, thermally molded to said means for providing flexibility and stability, and detachably attached to said means for providing steps;
means for providing support for the protective step cover;
means for providing structural integrity, structurally molded to said means for providing support for the protective step cover, and rigidly connected to said means for providing a stationary frame;
means for providing a structural frame, structurally molded to said means for providing structural integrity, and structurally molded to said means for providing support for the protective step cover; and
means for providing structural integrity and attachment, structurally molded to said means for providing a structural frame.

2. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing a stationary frame comprises a rectangular, metal supporting structure.

3. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing steps comprises a rectangular, concrete flight of steps.

4. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing traction comprises a rectangular, plastic, in a variety of colors, surface having horizontal grooves protective step cover top, having a horizontal surface with its length greater than its width.

5. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing flexibility and stability comprises a rectangular, plastic, in a variety of colors protective step cover front and rear, having a flat vertical surface with its length greater than its height.

6. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing attachment to steps and to eliminating moisture comprises a rectangular, plastic, in a variety of colors protective step cover bottom, having a flat horizontal surface with its length greater than its width and an open center section and parallel radius drip edges.

7. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing support for the protective step cover comprises a rectangular bracket top, having a flat horizontal supporting surface with its length greater than its width.

8. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing structural integrity comprises a rectangular bracket sides, having a flat vertical surface with its width greater than its height and holes for attachment.

9. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing a structural frame comprises a rectangular bracket front and rear, having a flat vertical surface with its length greater than its height.

10. The staircase protective step cover and or replacement step in accordance with claim 1, wherein said means for providing structural integrity and attachment comprises a rectangular bracket bottom, having a flat horizontal surface with its length greater than its width and an open center section for access.

11. A staircase protective step cover and or replacement step for protecting the concrete steps from deteriorating and versatility of protecting and or replacing the concrete steps in their entirety, comprising:

a rectangular, metal supporting structure, for providing a stationary frame;
a rectangular, concrete flight of steps, for providing steps, rigidly connected to said supporting structure;
a rectangular, plastic, in a variety of colors, surface having horizontal grooves protective step cover top, having a horizontal surface with its length greater than its width, for providing traction;
a rectangular, plastic, in a variety of colors protective step cover front and rear, having a flat vertical surface with its length greater than its height, for providing flexibility and stability, thermally molded to said protective step cover top;
a rectangular, plastic, in a variety of colors protective step cover bottom, having a flat horizontal surface with its length greater than its width and an open center section and parallel radius drip edges, for providing attachment to steps and to eliminating moisture, thermally molded to said protective step cover front and rear, and detachably attached to said flight of steps;
a rectangular bracket top, having a flat horizontal supporting surface with its length greater than its width, for providing support for the protective step cover;
a rectangular bracket sides, having a flat vertical surface with its width greater than its height and holes for attachment, for providing structural integrity, structurally molded to said bracket top, and rigidly connected to said supporting structure;
a rectangular bracket front and rear, having a flat vertical surface with its length greater than its height, for providing a structural frame, structurally molded to said bracket sides, and structurally molded to said bracket top; and
a rectangular bracket bottom, having a flat horizontal surface with its length greater than its width and an open center section for access, for providing structural integrity and attachment, structurally molded to said bracket front and rear.

12. A staircase protective step cover and or replacement step for protecting the concrete steps from deteriorating and versatility of protecting and or replacing the concrete steps in their entirety, comprising:

a rectangular, metal supporting structure, for providing a stationary frame;
a rectangular, concrete flight of steps, for providing steps, rigidly connected to said supporting structure;
a rectangular, plastic, in a variety of colors, surface having horizontal grooves protective step cover top, having a horizontal surface with its length greater than its width, for providing traction;
a rectangular, plastic, in a variety of colors protective step cover front and rear, having a flat vertical surface with its length greater than its height, for providing flexibility and stability, thermally molded to said protective step cover top;
a rectangular, plastic, in a variety of colors protective step cover bottom, having a flat horizontal surface with its length greater than its width and an open center section and parallel radius drip edges, for providing attachment to steps and to eliminating moisture, thermally molded to said protective step cover front and rear, and detachably attached to said flight of steps;
a rectangular bracket top, having a flat horizontal supporting surface with its length greater than its width, for providing support for the protective step cover;
a rectangular bracket sides, having a flat vertical surface with its width greater than its height and holes for attachment, for providing structural integrity, structurally molded to said bracket top, and rigidly connected to said supporting structure;
a rectangular bracket front and rear, having a flat vertical surface with its length greater than its height, for providing a structural frame, structurally molded to said bracket sides, and structurally molded to said bracket top; and
a rectangular bracket bottom, having a flat horizontal surface with its length greater than its width and an open center section for access, for providing structural integrity and attachment, structurally molded to said bracket front and rear.
Patent History
Publication number: 20080229685
Type: Application
Filed: Mar 19, 2007
Publication Date: Sep 25, 2008
Inventor: David Brian Uncles (Salt Lake City, UT)
Application Number: 11/725,257
Classifications
Current U.S. Class: Stepped; E.g., Stair (52/182); Stair (52/741.2); Protection (52/741.3)
International Classification: E04F 11/16 (20060101);