Patent Publication Number: US-6216819-B1

Title: Kneeling board for roofers

Description:
This application claims the benefit of Provisional Application 60/052630 filed on Jul. 16, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to a kneeling board for roofers, having an anti-slip pad for attachment to the underside of the board. The kneeling board is especially well suited for use by roofers and others working on steeply inclined surfaces. 
     2. Description of Related Art 
     Roofers and other construction workers that commonly work on steeply inclined surfaces often have difficulty maintaining their working positions, and roofers, especially, end up doing a considerable amount of their work while kneeling on the inclined surface. 
     The rough surface texture of the plywood sheathing, the backing paper, and especially of the commonly-used asphalt shingles, generally provides adequate frictional forces to hold the worker&#39;s knees and feet in place. 
     However, the hardness of those materials makes working on one&#39;s knees extremely uncomfortable and the worker must therefore take frequent breaks to relieve the pressure from the knees. In addition, the abrasiveness of these roofing materials quickly wears out the knee areas of the worker&#39;s clothing and greatly accelerates the wear on the shoe soles. The stone gravel that makes up the upper surface of asphalt shingles is highly abrasive, and the gravel texture can produce extremely uncomfortable pressure concentration on the worker&#39;s knees at the points of contact between the knees and the pieces of gravel. 
     While there are oftentimes foot supports temporarily attached to the roof to provide the roofer with more secure footing, and to relieve, to a limited extent, the pressure on the worker&#39;s knees, such supports do not provide adequate comfort to improve worker efficiency by reducing the number or length of work breaks. 
     A roofing aid on which the roofer can sit or kneel was proposed in U.S. Pat. No. 4,230,202. That roofing aid employs an anti-slip underlayer substantially permanently affixed into a frame, which has a sitting or kneeling surface as its upper surface. That roofer&#39;s aid further does not provide a foothold surface for retaining a secure footing on the device when the worker is working from a kneeling position. 
     It is a principal object of the present invention to provide a kneeling board for use in working on inclined surfaces that has an easily removable and replaceable anti-slip pad at the underside of the board, a resilient kneeling pad on an upper surface of the board, and a foot-engaging projection portion on the board, whereby a worker can kneel on the pad and secure his foot or feet against the projection. 
     It is another principal object of the present invention to provide a kneeling board that will remain in place on a sloped roof surface, and which provides a comfortable kneeling surface for the worker, and which provides an area at which the worker can secure his feet or toes to gain a foothold on the kneeling board. 
     SUMMARY OF THE INVENTION 
     The above and other objects of the present invention are achieved by removably securing a foam pad to an underside of a substantially rigid board element, and providing a resilient kneeling pad on an upper surface of the board element. The invention further achieves the above objects by providing an upwardly projecting flange extending preferably substantially perpendicular to the plane of the board element, and spaced apart from an edge of the kneeling pad, so as to create a channel for insertion of the worker&#39;s shoed feet or toes, such that the worker can gain a foothold on the kneeling board itself. This greatly improves the worker&#39;s stability and further distributes the worker&#39;s weight, to some degree, between the knees and the feet, when kneeling. 
     The foam pad will engage the roofing surface and will deform under the weight of the kneeling board, and/or the worker, such that the pad will securely grip the surface and substantially prevent the kneeling board from sliding along the surface. The removable foam pad is preferably secured to the underside of the board by hook-and-loop fasteners, such that, when the foam pad becomes worn, it can be readily replaced by a new pad. 
     To obtain the desired anti-slip or gripping properties, while maintaining a reasonable measure of durability, which are two competing interests, it has been determined that both open- and closed-cell foam materials provide an excellent combination of these properties. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features of the present invention and the attendant advantages will be readily apparent to those having ordinary skill in the art and the invention will be more easily understood from the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings wherein like reference characters represent like parts throughout the several views. 
     FIG. 1 is a top plan view of a kneeling board according to a preferred embodiment of the invention. 
     FIG. 2 is a side view of a kneeling board having a replaceable anti-slip pad secured thereto, wherein the kneeling board is laid on its side on a sloping surface. 
     FIG. 3 is a substantially schematic bottom plan view showing an alternative layout of the anti-slip pad of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, a kneeling board generally designated at  10  is illustrated. The kneeling board  10  preferably comprises a substantially rigid board element  12  having an anti-slip pad  14  releaseably attached to an underside  16  of the board element. The board element  12  further preferably has a kneeling pad  18  secured to an upper surface  20  of the board element. Finally, the board element  12  itself preferably has a flange or projection  30  extending perpendicularly upwardly from the upper surface  20  of the board element, along one edge, termed the downslope edge  32  of the kneeling board. 
     Board element  12  is preferably constructed of a substantially rigid plastic or polymer sheet material. As used herein, the term “substantially rigid” is intended to mean of sufficient rigidity to render the kneeling board assembly self-supporting and shape retaining, without the need for brackets, frames, or other reinforcing elements. The board element may preferably be on the order of 0.375 inches thick. Other suitable materials and thickness will be readily apparent to persons skilled in the art upon reading this disclosure. 
     As best seen in FIG. 1, the plan shape of the upper surface  20  of the board element  12  is rectangular, and the preferred dimensions are 24 inches on the short edge, of which downslope edge  32  is one, by 30 inches. The worker&#39;s feet will generally be at downslope edge  32 , and the worker&#39;s knees will fall somewhere in the center of the kneeling pad  18 . The additional length, to the 30-inch length, is provided to give the worker space to rest his or her hands, and/or to place work materials in a convenient location. The kneeling pad  18  extends across the vast majority of the upper surface  20  of board element  12 , extending to within approximately two (2) inches of each edge of the board element. 
     As seen in FIG. 2, the kneeling pad  18  projects upwardly from upper surface  20  of board element  12 . The kneeling pad  18  is preferably made of a closed-cell foam material, having a thickness of two (2) inches. The kneeling pad is preferably substantially permanently secured to upper surface  20 , as by gluing. 
     Alternatively, the pad  18  may be removably secured, as discussed in greater detail herein with respect to anti-slip pad  14 . The closed-cell foam provides some water-absorption resistance. The pad  18  may, however, further be coated with a water-impervious coating, such as a nylon film or coating, or other known coatings used on closed-cell foam products. Open-cell foam layers could also be used for this kneeling pad, however, open-cell foams will generally require the use of the water-impervious coating to impart resistance to absorbing water. 
     While the preferred characteristics for the kneeling pad have been discussed herein, it will be readily apparent that the main purpose and function of the kneeling pad is to provide cushioning for the worker&#39;s knees, and any material suitable for such use may be employed for kneeling pad  18 . 
     Projection  30  provides an important feature in the present invention. Pad  18  is deliberately spaced apart from projection  30 , so as to create a channel  34  bounded on three sides by the projection  30 , the upper surface  20  of board element  12 , and the side surface  36  of kneeling pad  18 . The projection preferably extends to a greater distance away from upper surface  20  then does kneeling pad  18 . In a preferred embodiment, projection  30  would extend five (5) inches from the upper surface  20 . 
     The channel  34  allows the worker, after the worker is kneeling at a desired location on the kneeling board  10 , to secure his feet or toes (in shoes) against the projection  30 , and inserted into channel  34 . This provides the worker with a secure foothold on the kneeling board  10 , thereby increasing the stability of the worker. The ability to gain such a foothold further allows the worker to distribute his weight, to some degree, between his knees and his feet, to further remove load from the knees. 
     The edge at which projection  30  is located is referred to as the downslope edge because the worker will generally work with his feet below his body and head, and thus the projection will be oriented by the worker such that the projection will be “downslope” from the remainder of the kneeling board  10 . 
     The kneeling board of the present invention is designed for long-lasting life. The anti-slip pads are subjected to accelerated wear when used on roofing surfaces, particularly the asphalt shingles, thus severely curtailing the service life of a simple pad. It has been determined, in accordance with the present invention, that the desired combination of high traction and increased service life is obtained by providing a removable and replaceable open-cell or closed-cell foam pad  14  secured to the underside  16  of the kneeling board  10  that would normally be in contact with the sloped surface when the kneeling board is placed on the surface. 
     When the roofer positions the kneeling board  10  in a desired work location on a roof  100  or other sloping surface, the anti-slip pad  14  engages the roof surface  100 , whether it is the bare plywood sheathing, the backing paper, or, most often, the gravel surface of an asphalt shingle. The material for the pad is selected to be substantially resilient, such that the weight of the kneeling board will cause the foam pad to deform at least slightly under the weight of the board, to securely engage the roof surface, and to increase the area of contact and frictional forces between the roof surface and the pad  14 . The foam pad will deform to a much greater extent providing extremely secure engagement, once the weight of the worker is added to the kneeling board. 
     Preferably, the anti-slip pad  14  will cover substantially the entire underside of the kneeling board  10 . Alternatively, strips of the foam pad material may be removably attached by hook and loop fasteners (not visible in FIG. 3) along the periphery of the board, and crossing the board inside the periphery, as shown schematically in FIG.  3 . 
     Anti-slip pad  14  may preferably be constructed of an open-cell foam material for anti-slip purposes, however, closed-cell foam material should also be suitable. The pad  14  preferably has a density in the range of about 1.5 to about 30 pounds per cubic foot (lb/ft. 3 ) 
     An even more preferred range of densities for the foam pad is between about 4.5 lb/ft. 3  and 16 lb/ft. 3 , as products in that range are believed to provide a very desirable combination of high traction and suitably long wear, so that the pad need be replaced only infrequently. A open-cell foam pad having a density of about 15 lb/ft. 3  has been shown to be highly suitable for use. 
     Several types of foam material should be suitable for use. Polyurethane, Neoprene, Vinyl Nitrile, Styrene-Butadiene Rubber (SBR), Polyethylene (PE), ethyl vinyl acetate (EVA), ethylene propylene terpolymer (EPT), EPT/PE/ButylRubber, Neoprene/EPT/SBR, epichlorohydrin (ECH), and nitrile (NBR) are among the types of polymers that would provide suitable foam layers for use as an anti-slip pad  14  in the present invention. Polyurethane is the preferred material at this time for the open-cell foam. Neoprene and vinyl/nitrile appear to be the most promising polymers among the above polymers for a closedcell foam, at the present time. 
     Polyurethane open-cell foam is believed to be commonly available in the preferred density range. Certain closed cell foams having the preferred characteristics noted above are commercially available through the Rubatex® company. Among the closed-cell foam products currently available through Rubatex, the products sold under the designations R-411-N (10-16 lb/ft. 3 ), R-1800-FS (4.5-8.5 lb/ft. 3 ), G-207-N (15-30 lb/ft. 3 ) and G-231-N (10-20 lb/ft. 3 ), are believed to be particularly suitable for use as anti-slip pads  14  when a closed-cell foam is used in the present invention. 
     The relatively high density and open-cell characteristics of the foam material are believed to be important features in terms of providing the necessary anti-slip characteristics for the anti-slip pad, as well as providing a desirable degree of durability as used in the roofing applications. 
     Various harder (less resilient) and softer (more resilient) materials may have drawbacks that render them unsuitable for providing an anti-slip pad for a kneeling board used by roofers and other persons working on roofs and other sloping surfaces. A non-foamed polymer material, for example, will generally lack sufficient resiliency or ability to deform under the weight of the kneeling board, and will thus not adequately grip the surface. The foams employed as the anti-slip pad  14  in the present invention provide greatly improved anti-slip characteristics, and the resiliency and softness (relative to the hardness of the gravel particles on the shingles) of the material allows the foam material to deform around the gravel particles and to securely grip the asphalt shingles. The anti-slip pad is able to conform to the rough, irregular surface by deforming around the gravel particles, instead of simply pushing against the particles, and possibly dislodging them in the process. 
     Closed-cell foam material, in general, appears to have a greater resistance to wear when used on shingles and roofing surfaces, as compared to open-cell foams that have previously been studied. However, open-cell foams appear generally to provide enhanced anti-slip properties. The use of a high-density closed-cell foam for the removable anti-slip pad  14  thus would provide the advantage of increased wear life. Because the pad is replaceable, however, the improved anti-slip properties of the open-cell foam makes it the preferred material. High-density open-cell and closed-cell foam anti-slip pads will also stand up reasonably well to other abrasive surfaces onto which the kneeling board  10  may be placed in a typical day, such as concrete sidewalks, and concrete or asphalt driveways. 
     The fastening means for the anti-slip pad  14  is preferably a sheet or layer  22  of the loop elements of a hook-and-loop type fastener substantially permanently secured to the anti-slip pad  14  by adhesive or other suitable means. One expected preferred manner of effecting a permanent securement of sheet  22  to anti-slip pad  14  is to laminate sheet  22  onto the foam layer  14  as the foam layer is being produced. The underside of the kneeling board  10  will have secured thereto a corresponding sheet  24  of hook-type fasteners, at a location where the pad  14  is to be secured. The sheet  24  of hook-type fasteners is desirably secured to the kneeling board  10  with a long-lasting adhesive, such as an epoxy-based adhesive. Fastening means other than hook-and-loop fasteners may be employed in place of the hook-and-loop fasteners. 
     The preferred thickness of the anti-slip pad  14  is in the range of {fraction (1/4 +L )} inch to {fraction (3/4 +L )} inch. If the anti-slip pad were thinner than {fraction (1/4 +L )} inch, the anti-slip pad might not provide sufficient service life when used on a daily basis, as the foam will be worn away by the shingles. Anti-slip pads thicker than ¾ inch would provide even greater service life, but at the expense of making the pad  14  overly thick and possibly too far elevated from the work surface. 
     When the pad  14  becomes worn as a result of being abraded away during extended use, the worn pad  14  may be easily removed and a new pad  14  having a sheet  22  of the necessary type of fastening means may be quickly secured to the complementary fastening means  24  previously secured to the kneeling board  10 . 
     It will be apparent to those skilled in the art that modifications and variations can be made to the kneeling board and removably attached anti-slip pad of the present invention, without departing from the scope or spirit of the present invention. Thus, it is intended that the present invention cover such modifications and variations of the invention, provided they come within the scope of the appended claims and their equivalents.