Patent Application
20180347217
The present invention is in the field of construction, particularly worksite safety.
For any construction site, safety of workers and equipment is an important aspect that must always be taken into consideration. Even so, according to statistics from 2014 obtained from the United States Department of Labor, 4,821 workers were killed on the job in the construction trade in that year. Of those 4,821 fatalities, roughly 40% of them are attributed to fall-related accidents, which is many times greater than the second leading cause of construction worker fatality—electrocutions at about 8.2%. It is even more important that falls are prevented, because falls may happen spontaneously, and usually result in instant death if the height is great enough.
One possible explanation for the high number of fall-related fatalities may be that the currently available solutions are seen as too time-consuming, or bothersome to properly install and set up. Another reason may be that the presently available solutions that are easy and fast to set up aren't as effective in preventing falls as they need to be.
Therefore, what is clearly needed is a safety guardrail system for use in high-rise construction, that allows workers to quickly and easily put up and take down the system on job sites, while maintaining a high degree of safety.
In one embodiment of the invention a system for providing a guard rail on a concrete floor in construction of a high-rise building is provided, comprising a plurality of stanchions for holding cable for the guard rail, individual ones of the stanchions comprising a vertical member with holes or openings for holding cable for the guard rail, and one or more laterally extending reinforcement legs fastened at an upper extremity to the vertical member, and extending downward at an angle to the lowermost level of the vertical member, each of the vertical member and the one or more reinforcement legs having a base plate in a common plane orthogonal to the height of the vertical member, and each of the base plates having a vertical through-hole, and a plurality of embeds screwed into a base of a mold for forming the concrete floor, each embed presenting at an uppermost extremity a vertically-oriented nut, the embeds positioned in sets in patterns to present the vertically-oriented nuts in matching patterns of the vertical through-holes in the separate base plates for each stanchion, the embeds encased in the concrete floor. The stanchions are bolted through the through holes in the base plates to the nuts presented by the embeds at an upper surface of the concrete floor, and guard rails are formed by passing cable through the holes or openings for holding cable for the guard rail.
In one embodiment, individual ones of the stanchions are corner stanchions having a vertical member, two laterally-extending reinforcement legs, and three base plates with through-holes, and the corner stanchions are used at corners, and other positions where the cable guard rail changes direction. Also in one embodiment, stanchions are placed around a periphery of a concrete floor at intervals of no more than eight feet, with corner stanchions each twenty-four feet, and intermediate or single stanchions at eight-foot spacing between corner stanchions. Also in one embodiment, a guard rail is formed from cable at two separate heights. And in one embodiment, the guard rail is formed of cable at more than two heights.
In one embodiment of the system, the embeds are screwed to the base of the mold prior to the pouring of concrete, and the vertically oriented nuts are covered to prevent concrete from entering the female thread of the nuts. Also in one embodiment, cleats are provided at a lowermost extremity of individual ones of the stanchions, with holes for fastening a toe-board to prevent objects from sliding or rolling off the edge of the concrete floor. Also in one embodiment embeds comprise a raised horizontal surface with vertical legs at each end, and a vertical post joined to the horizontal surface having the vertically-oriented nut at an uppermost extremity. Also in one embodiment, the overall height of the embed from the bottom of the vertical legs to the uppermost edge of the vertically-oriented nut is exactly the desired thickness of the concrete floor. And in one embodiment the vertical members are fashioned from ninety-degree angled steel rails, with predrilled holes for the cables to form the guard rail.
In another aspect of the invention a method for providing a guard rail on a concrete floor in construction of a high-rise building is provided, comprising screwing a plurality of embeds into a base of a mold for forming the concrete floor, each embed presenting at an uppermost extremity a vertically-oriented nut, the embeds positioned in sets in patterns to present the vertically-oriented nuts in specific patterns of one, two or three nuts, pouring concrete into the mold, encasing the embeds up to an upper edge of the vertically-oriented nuts, placing a plurality of stanchions for holding cable for the guard rail over the patterns of vertically-oriented nuts, individual ones of the stanchions comprising a vertical member with holes or openings for holding cable for the guard rail, and one or more laterally extending reinforcement legs fastened at an upper extremity to the vertical member, and extending downward at an angle to the lowermost level of the vertical member, each of the vertical member and the one or more reinforcement legs having a base plate in a common plane orthogonal to the height of the vertical member, and each of the base plates having a vertical through-hole, the through holes of the base plates forming a matching pattern with the patterns of nuts presented by the encased embeds, bolting the stanchions to the concrete floor through the through holes in the base plates to the nuts presented by the embeds at an upper surface of the concrete floor, and forming guard rails by passing cable through the holes or openings for holding cable for the guard rail.
In one embodiment of the method, individual ones of the stanchions are corner stanchions having a vertical member, two laterally-extending reinforcement legs, and three base plates with through-holes, and the corner stanchions are used at corners, and other positions where the cable guard rail changes direction. Also in one embodiment, stanchions are placed around a periphery of a concrete floor at intervals of no more than eight feet, with corner stanchions each twenty-four feet, and intermediate or single stanchions at eight-foot spacing between corner stanchions. In one embodiment, a guard rail is formed from cable at two separate heights. And in one embodiment, the guard rail is formed of cable at more than two heights.
In one embodiment, the embeds are screwed to the base of the mold prior to the pouring of concrete, and the vertically oriented nuts are covered to prevent concrete from entering the female thread of the nuts. Also in one embodiment, cleats or provided at a lowermost extremity of individual ones of the stanchions, with holes for fastening a toe-board to prevent objects from sliding or rolling off the edge of the concrete floor. Also in one embodiment embeds comprise a raised horizontal surface with vertical legs at each end, and a vertical post joined to the horizontal surface having the vertically-oriented nut at an uppermost extremity. In one embodiment, the overall height of the embed from the bottom of the vertical legs to the uppermost edge of the vertically-oriented nut is exactly the desired thickness of the concrete floor. And in one embodiment, the vertical members are fashioned from ninety-degree angled steel rails, with predrilled holes for the cables to form the guard rail.
Generally, what is provided in an embodiment of the invention is a guardrail system that is simple and easily erected, dismantled, and transported to another location, while adhering to federal safety standards established by agencies such as the Occupational Safety and Health Administration (OSHA), and providing an extra level of strength and reliability over any conventional system for the same purposes at the time of filing the present patent application.
The body 104 may have a plurality of pre-drilled holes 102A-102D used for cabling to form guard rails at appropriate heights. Uppermost holes 102A and 102B in this embodiment may be present at a height of approximately 42 inches from the bottom of metal body 104 to meet top rail standards established by OSHA regulations, and bottom holes 102C and 102D are present at a height of 21 inches from the bottom of metal body 104 to meet mid-rail standards established by OSHA. In other embodiments, the holes 102A-102D may be present at different heights in order to meet other established safety standards if necessary, as well as additional holes to create a greater number of rails. This embodiment utilizes metal cabling threaded through the pre-drilled holes 102A-102D for handrails, however, it may possible to adapt other embodiments of the present invention to utilize and include means to create handrails from other materials commonly used in the art, for example metal pipes or 2×4's.
In construction, in one example, first base plate 106A, second base plate 106B, and gusset 104 are attached to the bottoms of kicker 103A, kicker 103B, and metal angle body 101 respectively. First base plate 106A, second base plate 106B, and gusset 104 may have pre-drilled holes, first hole 107A, second hole 107B, and third hole 105, respectively, to fit a standard-sized bolt, for example a ⅝″ coil bolt according to this embodiment of the present invention, to anchor corner stanchion 100 rigidly to a working surface. For usage on a concrete slab surface, anchors or embeds, described in further detail below, may be used. For usage on more pliable materials, for instance wood flooring, the stanchions may be anchored directing by bolting into the flooring.
The toe-board clips 108A and 108B, attached to the adjacent sides of gusset 104, may be used to hold a rigid member, for example a length of 2×4, in place to act as a toe-board as a preventive measure for constraining objects that may bounce or roll off an edge, which may be hazardous to people or equipment below. The toe-board clips 108A and 108B may have holes predrilled in order to hold the rigid member in place. Toe-board clips may be present on other stanchions as well in order to provide additional holding points to increase sturdiness of a toe-board.
Threaded nut 404 may be a standard sized nut, a nut for a ⅝″ coil bolt for instance, in which one of the various stanchion types presented above may be anchored by bolts into the nut projected. The top edge of threaded nut 404 is positioned at approximately the intended height of a concrete slab after being placed and fastened, so that after spreading and leveling of the wet concrete the top surface of the bolt 404 may sit flush with the top of the concrete slab. This may ensure that once fastened to an embed, a fastened stanchion makes maximum contact with the surface of a concrete slab thus providing maximum strength, and security.
In the above and following examples, a ⅝″ coil bolt size is used system-wide, but it should be understood that the usage of varying sizes of bolts, and embeds of varying heights may be used in a single system without diverting from the scope of the present invention.
In the course of beginning a new floor in a high-rise building, a mold is provided to contain the concrete as it is poured. The bottom of this mold is either wooden or metal. Before concrete is poured, embeds 400 are placed in all locations where threaded holes will be needed at the top of the concrete slab, providing anchor points for the base plates of all stanchions to be placed to retain cable for safety rails. As may be seen in
For a location where two or more embeds are needed because there will be two or more anchor points required for a stanchion, a positioning template is placed on the floor of the mold, the embeds are placed in the template and screwed to the floor, and then the template guide is removed and used elsewhere.
Corner stanchions are used at all corners of a layout, as extra strength is needed at these points. Along an edge of the mold, embeds for stanchions are spaced apart typically at a center distance of eight feet. An extra strong corner mount may be placed every 30 to 40 feet, whether that position is a corner, or not, to provide maximum strength for safety. This is not an invariable condition, and the spacing in some embodiments may be greater or smaller. Intermediate stanchions may be placed between the corner stanchions, and in places where the distance is less than eight feet, or where space is limited, single stanchions may be used.
Once all embeds are in place for a concrete slab, prior to pouring the slab, the concrete may be poured. The concrete rises to the top edge of nuts 404 of the embeds, which may be covered or plugged in this operation to prevent fouling of the internal threads of the bolts. When the concrete is set, stanchions are bolted into place, at all points presented for each stanchion, depending on the type of stanchion, and may be torqued securely in place. In the prior art, single stanchions with male threaded posts are screwed into internal threads of embeds, and these cannot be torqued into place securely, and provide an inferior-strength stanchion for cable.
Once all stanchions are bolted into place in the present invention, cable may be strung through the holes in the stanchions, typically at two separate heights, but in some embodiments more than two, and the cable is tensioned, to provide the guardrails. Because of the multiple anchor points for stanchions in the present invention, the sideways force-resistance is far greater than in prior art systems, and the cable may be tensioned tighter, such that the guardrail system provided may withstand substantially greater loads than in the prior art.
In this example, a top rail 501 and middle rail 508 are formed from lengths of steel cable that are fastened together with loop-ends 502A and 502B created with a plurality of crimps 503A-D, more or less crimps may be used as necessary. The loop-ends 502A and 502B may be created on-site so that the cables may be a customized length for any specific job, and need not be pre-crimped. Alternatively, the top rail 501 and the middle rail 508 may be separate cables that have been tightened at the ends to other fixtures, such as hooks, eye bolts, or the like, to make the rails 501 and 508 rigid.
A toe-board 505 may be inserted into clips present at the base of the various stanchions of system 500 but not visible in
In this example, no particular spacing is shown in the figure, but in installation, the corner stanchion, with three base plates providing a wide and strong stance, are used at corners, and other points where cable direction changes, and typically are also used at now more than twenty-four feet apart in a straight run, with end or single stanchions at no more than eight-foot intervals between. This has been determined by the inventors to provide an extremely strong guard-rail barrier, far stronger than required by codes and OSHA requirements.
The removal process is simply to remove the coil bolts and transport the stanchions away. The embeds are left inside the concrete slab, as typically flooring is laid on top of a concrete slab, for instance hardwood or carpeting.
It will be apparent to one with skill in the art, that the embodiments described above are specific examples of a single broader invention which may have greater scope than any of the singular descriptions taught. There may be many alterations made in the descriptions without departing from the spirit and scope of the present invention.
