Abstract:
A protective device is provided to prevent humans from accidentally falling through openings in roofs or floors, including the domes of curb-mounted skylights and temporary utility chases that are surrounded by a raised curb. The protective device is secured to the raised curb by clamps that do not penetrate the curb, skylight frame, floor or roof, and therefore do not compromise the water-tight integrity thereof. In the case of an opening type skylight, by securing the protective device to the curb, no interference is contributed to the skylight to hinder the opening mechanism of the skylight.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a protective device and more particularly to a protective device for roof and floor openings that are surrounded by a raised curb. The invention is installed to prevent a human from accidentally falling through such an opening to the floor below. 
     Domed skylights are a particular type of roof opening that present a constant danger to roof and utility workers working on flat roofs. The domes cannot support the weight or impact force of a fallen human, and thus have been the cause of many deaths and serious injuries due to collapse and breakage upon impact, sending the fallen human crashing to the floor below. 
     The Occupational Safety and Health Administration (OSHA) has promulgated regulations specifically requiring employers to provide fall protection to workers. Current OSHA regulations require “each employee on walking/working surfaces shall be protected from falling through holes (including skylights) more than 6 feet (1.8 m) above lower levels, by personal fall arrest systems, covers, or guardrail systems erected around such holes.” (29 C.F.R. § 1926.501(b)(4)(i) (1999)). 
     Existing skylight fall protection devices generally comprise a skylight cover or metal screening system extending over the domed skylight. The cover or screening is typically fixed to the skylight frame via bolted connections, essentially becoming part of the skylight frame. (See, e.g., U.S. Pat. No. 5,502,934). Such protective means have a negative effect upon the operation of opening type skylights because their excess weight can hinder the spring-loaded mechanism that opens the skylight. Even absent the negative effect of their weight, cover and screening type protective devices often prevent the skylight from opening by blocking the opening path of the skylight dome. In addition, the bolted attachment means of prior art protective devices impair the water-tight integrity of the skylight frame or the roof creating portals through which water may enter. The attachment of these prior art protective devices may in some or many cases negate certification which the skylight had previously obtained. 
     Utility chases commonly found in the floors of high-rise buildings and skyscrapers under construction present a second formidable danger to proximal workers. Typically, utility chases are surrounded only by a raised curb which is not effective to prevent workers from falling through the chase to the floor below. 
     There is a need in the art for an effective floor or roof opening protective device that does not hinder the spring-loaded mechanisms of opening skylights, detract from the water tight integrity of the mounting surface (i.e. curb, skylight frame, roof or floor), or block the opening path of a domed skylight. 
     SUMMARY OF THE INVENTION 
     A protective device is provided for an opening in a roof or floor that is surrounded by a raised curb. The protective device has a perimeter barrier wall adapted to surround the opening and is effective in preventing a human from traversing therethrough. Clamps are connected to the barrier wall, the clamps being capable of effectively clamping the barrier wall to the raised curb without penetrating the curb, floor or roof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a first preferred embodiment of a protective device of the present invention. 
     FIG. 2 is a side elevational view of the preferred embodiment of the present invention shown in FIG.  1 . 
     FIG. 3 is a top view of the preferred embodiment of the present invention shown in FIG.  1 . 
     FIG. 4 is a close-up perspective view of a vertical support member showing preferred embodiments both of a clamping means, and of a detachable connection means for attaching long rails to adjacent vertical support members according to the present invention. 
     FIG. 5 is a perspective view of a second preferred embodiment of a protective device of the present invention designed to accommodate opening type skylights. 
     FIG. 6 is a perspective view of a third preferred embodiment of a protective device of the present invention designed to accommodate opening type skylights. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A protective device  10  is provided having clamping means for rigidly securing the protective device  10  to a curb surrounding a roof or floor opening. As used herein, “curb” means a raised barrier, typically concrete though other suitable materials can be used, projecting upward at least 1, 2, 3, 4, 5, or 6 inches from a floor or roof and surrounding an opening therein. 
     Referring to FIGS. 1 and 2, a preferred embodiment of a protective device  10  according to the invention is shown having a first short wall  6 , a second short wall  7 , a first long wall  8 , and a second long wall  9 , with all four walls forming a perimeter barrier wall that completely surrounds an opening in a floor or roof and is effective to prevent a human from progressing therethrough and accidentally falling through the enclosed opening. The perimeter barrier wall has a rectangular projection when viewed from above as best seen in FIG.  3 . Less preferably, the perimeter barrier wall can have a projection of some other shape when viewed from above, for example circular, elliptical, trapezoidal, pentagonal, hexagonal, or any other closed polygon configuration. 
     Though the walls that form the perimeter barrier wall of the protective device  10  are described below as comprising rails and cross-braces attached to vertical support members in accordance with the most preferred embodiments of the invention, less preferably the walls may comprise plywood, sheet metal (such as aluminum, steel, etc.), netting (cloth, plastic, rubber, or any other suitable material), or any other suitable barrier means. 
     Most preferably, vertical support members  12 ,  14 ,  16 ,  18  are disposed at the intersections of the short walls  6 ,  7  with the long walls  8 ,  9  forming the corners of the protective device  10 . Each vertical support member  12 ,  14 ,  16 ,  18  has a roof or surface pad  20 ,  22 ,  24 ,  26  at its base. Preferably, each roof pad  20 ,  22 ,  24 ,  26  has rounded corners and an upward slanted hem or flange along each edge to minimize point loading and to prevent the pad digging in to the roof surface. The vertical support members  12 ,  14 ,  16 ,  18  are connected along the first and second short sides  6  and  7  respectively by first and second short base rails  30  and  31 , first and second short middle rails  32  and  33 , and first and second short upper rails  34  and  35 . Similarly, the vertical support members  12 ,  14 ,  16 ,  18  are connected along the first and second long walls  8  and  9  respectively by first and second long base rails  40  and  41 , first and second long middle rails  42  and  43 , and first and second long upper rails  44  and  45 . 
     Most preferably, the first and second long base rails  40 ,  41  and the first and second short base rails  30 ,  31  are attached to their respective vertical support members near the bases thereof as shown in FIGS. 1-2 so as not to obstruct access to the inner clamping nut  76  of the clamps or clamp assemblies  62 ,  64 ,  66 ,  68  as described below. Less preferably, the first and second long base rails  40 ,  41  and first and second short base rails  30 ,  31  can be attached to their respective vertical support members some distance above the point of attachment of the clamps or clamp assemblies  62 ,  64 ,  66 ,  68 . Cross braces  48  may optionally be provided to impart rigidity and stability to the protective device  10 . The cross braces  48  shown in FIGS. 1,  2 ,  5  and  6  are of a generally V-shaped configuration, though cross braces of any suitable configuration may be used. 
     In the most preferred embodiment of the invention, and as can best be seen in FIGS. 3 and 4, each of the long rails (long base rails  40 ,  41 , long middle rails  42 ,  43 , and long upper rails  44 ,  45 ) is removably attached to the vertical support members  12 ,  14 ,  16 ,  18  at either end by means of a bolt  80  and a nut  81 . Most preferably, each long rail has a crimped end  84  at the point of attachment to a vertical support member  12 ,  14 ,  16 ,  18 , with space left between the compressed sides of the crimped end  84  thus forming a tab socket  86  therein. The crimped end  84  has a first bolt hole  87  to accommodate a bolt  80  or other securing means. Each vertical support member  12 ,  14 ,  16 ,  18  has a tab  82  securely fastened thereto at the point of attachment of an adjacent long rail, the tab  82  having a second bolt hole  88  to accommodate a bolt  80  or other securing means. 
     When the protective device  10  is fully assembled, a tab  82  attached to a vertical support member  12 ,  14 ,  16 ,  18  fits snugly inside the tab socket  86  at a crimped end  84  of an adjacent long rail, and a bolt  80  and nut  81  rigidly secure the tab  82  within the tab socket  86 . Alternatively, crimped ends  84  can be provided without tab sockets  86 , wherein a tab  82  attached to a vertical support member  12 ,  14 ,  16 ,  18  is rigidly secured adjacent to and outside of a crimped end  84  of an adjacent long rail via a bolt  80  and a nut  81 ; similarly an L-shaped clip or bracket can be attached via welding to the end of the long rail, with the bottom of the L perpendicular to the longitudinal axis of the long rail and the upper part of the L extending parallel to tab  82 , but on one side or the other of the tab  82 , with a hole in the upper part of the L so that the L-shaped clip can be bolted to tab  82 . This rigid but separable construction facilitates ease of packaging and shipping of the protective device  10  which is cumbersome to transport when fully assembled. Additionally, separable construction facilitates interchangeability of long rails having variable lengths to accommodate floor or roof openings (such as domed curb-mounted skylights  100 ) of standard width but varying length. Least preferably, the long rails can be welded or attached to the vertical support members  12 ,  14 ,  16 ,  18  via other means known in the art. 
     Referring to FIG. 4, the following description of the novel clamping means of the present invention is provided and the figure contains reference numerals with respect to the vertical support member  12  and its associated clamp or clamp assembly  62 . However, it will be understood that each of the three remaining vertical support members  14 ,  16 ,  18  and respective clamps or clamp assemblies  64 ,  66 ,  68  are provided similarly as pictured in FIG.  4  and as described herein. A plurality of adjustment holes (preferably or at least three)  50 ,  51 ,  52  are provided in a vertical support member  12  and are spaced from each other and from the roof pad  20  preferably by no more than 2.5, more preferably 2.0, more preferably 1.5, more preferably 1.0 inches. A clamp or clamp assembly  62  is provided comprising a clamp angle  70  having a first clamp face  71   a  and a second clamp face  71   b  wherein the first and second clamp faces meet along a clamp edge  72 , a threaded rod  74  rigidly attached to and projecting outwardly from the clamp edge, and an inner clamping nut  76 . The clamp assembly  62  may optionally be provided with an outer nut  78  that is preferably removed when the protective device  10  is in use. 
     Once in place around a domed curb-mounted skylight  100  the protective device  10  is fixed in place by means of the clamp assemblies  62 ,  64 ,  66 ,  68  provided respectively on the vertical support members  12 ,  14 ,  16 ,  18 . The clamp angle  70  is compressed against the curb  102  of a domed curb-mounted skylight  100  by means of the inner clamping nut  76  and the threaded rod  74 . Clamping pressure is generated by tightening the inner clamping nut  76  in the direction of the vertical support member  12 . Because the inner clamping nut  76  is advantageously constrained against the vertical support member  12 , the threaded rod  74  is displaced inward from the vertical support member  12  along its longitudinal axis as the inner clamping nut  76  is tightened, thus compressing the clamp angle  70  against the curb  102 . It will be understood by one skilled in the art that by compressing the clamp angles  70  of all four clamp assemblies  62 ,  64 ,  66 ,  68  against the curb  102  of the domed curb-mounted skylight  100 , the protective device is held rigidly in place against the curb  102 . Optionally, the clamp faces of the clamp angles  70  can be provided with a resilient padded liner to prevent damage to the curb  102  from the force of the clamping pressure exerted by the clamp angles  70  against the curb. The resilient liner may be comprised of rubber, foam rubber, cork, wood, or any other suitable material. 
     The clamp assemblies  62 ,  64 ,  66 ,  68  are provided with sufficient clamping strength to withstand, with no displacement of the protective device  10  relative to the curb  102 , the impact force of a fallen human weighing 100, more preferably 120, more preferably 140, more preferably 160, more preferably 200, more preferably 250, more preferably 300, more preferably 400 pounds. Further, the clamp assemblies  62 ,  64 ,  66 ,  68 , are provided with sufficient clamping strength to prevent displacement of the protective device  10  relative to the curb  102  due to a sustained wind having a velocity of 30, more preferably 40, more preferably 50, more preferably 70, more preferably 100, more preferably 150, more preferably 200 miles per hour. 
     A protective device  10  secured to the curb  102  of a domed curb-mounted skylight  100  by means of clamp assemblies  62 ,  64 ,  66 ,  68  in the above described manner does not detract from the water tight integrity of either the roof or the skylight frame because no bolts are used and hence no holes are required. Further, by securing the protective device  10  to the curb  102  and not to the frame of an opening type skylight, the spring-loaded opening mechanism is not negatively affected because no weight is contributed to the frame of the opening type skylight. In addition, the roof pads  20  prevent point loading on the roof via the vertical support members  12 ,  14 ,  16 ,  18  that would otherwise result from the impact force of a fallen human against the protective device  10 . For these reasons, a protective device according to the present invention neither invalidates the F.M. or U.L. rating of a skylight, nor deleteriously effects the structural integrity of a roof. 
     In a second preferred embodiment of the invention, the protective device  10  comprises means to further accommodate opening type skylights by eliminating obstructions in the opening path of the skylight dome  101 . FIG. 5 shows one embodiment of an accommodating means according to the present invention. The protective device  10  is provided similarly as described with respect to other preferred embodiments above, with two principal differences: the first long middle rail  42  and first long upper rail  44  are missing therefrom in order to accommodate the dome  101  of an opening type skylight in the open position; and the protective device  10  further comprises a dome cage portion  104 . The dome cage portion  104  is comprised of vertical support members and long and short rails similarly as the protective device  10 , effectively doubling the width of the protective device  10 . Preferably, the dome cage portion  104  is removably attached to the vertical support members  12 ,  18  for ease of packaging and shipping, and most preferably the dome cage portion  104  is itself further collapsible by means of tabs  82  and tab sockets  86  in similar fashion as the most preferred embodiment of the invention described above. 
     A second accommodating means for opening type skylights according to the present invention is shown in FIG.  6 . In this embodiment, the first long middle and first long upper rails,  42  and  44 , are replaced respectively with a middle curved rail  46  and an upper curved rail  47  which form a bulge. Preferably, the middle and upper curved rails,  46  and  47 , have crimped ends  84  enclosing tab sockets  86 , and are removably attached to the vertical support members  12 , 18  in similar fashion as described above with respect to the long rails according to the most preferred embodiment of the invention. 
     In addition to curb-mounted skylights  100 , the protective device  10  of the present invention can also be used to protect humans from falling through utility chases commonly found in the floors of high-rise buildings and skyscrapers during construction. Such temporary openings are necessary for the installation of water pipes, electrical conduits, and other utilities. However, such openings present a formidable hard to construction workers because they are often unguarded except by a cement curb intended to prevent water seepage to the floors below. A protective device  10  according to the present invention can be installed to guard against accidental falls through such temporary openings. 
     Although the hereinabove described embodiments of the invention constitute the preferred embodiments, it should be understood that modifications can be made thereto without departing from the scope of the invention as set forth in the appended claims. For instance, the long rails can be permanently and irremovably attached to the vertical support members via welded connections or some other known means. Detachable connections are merely preferred, not required within the scope of the invention.