GUARDRAIL SAFETY BRACKET

Description

BACKGROUND OF THE INVENTION

The field of the invention relates to temporary guardrails erected at construction sites.

Temporary guardrails are erected at construction sites to prevent workers from falling or to isolate them from other hazards. A typical example of such a guardrail is shown in FIG. 1. For each post 106, a base board 100, such as a 2×4, is nailed or screwed into a substate 102, which may be in the nature of plywood or concrete. A vertically oriented triangular gusset plate 104, typically fashioned of plywood, is nailed to the base board 100. A vertical upright, post or stanchion 106, which typically is a single 2×4, but may be a double 2×4, is nailed to the gusset plate 104 and may be nailed to the base board 100 as well. Rails 108, 110 are nailed to the upright 106. A toe board 112 may be placed in front of the upright 106 to prevent tools and detritus from falling off of the substate 102 to regions below it.

The problem with these conventional temporary guardrails is that they have inadequate resistance to shear. The Occupational Safety and Health Administration (OSHA) requires that the guardrail be capable of withstanding, without failure, 200 pounds of pressure applied within two inches of the top of a 42-inch upright in an outward direction. The illustrated prior art temporary guardrail will fail at about 87 pounds of such pressure, by its nails being pulled out.

To remedy this problem, various guardrail sockets, brackets and shoes have been proposed. U.S. Pat. No. 10,767,386 to Hilliard describes a guardrail support that surrounds the uprights completely on two sides and incompletely on the other two sides. The commercial embodiment of this support is molded of plastic, traps water, and fails when subjected to freeze-thaw cycles. US Patent Appln. Pub. No. 2015/0021535 to Tomczak discloses a shoe anchor apparatus that appears to be molded or cast, and which has a completely enclosing socket for the upright(s). US Patent Appln. Pub. No. 2010/0171085 A1 to Webster, IV discloses a guardrail socket welded from multiple steel shapes. U.S. Pat. No. 3,669,580 to Fugate discloses a guard rail demountable socket meant for attachment to a margin of the substrate. U.S. Pat. No. 9,617,744 to House discloses a multiple-component guardrail safety system assembled from multiple plates. Even in view of these, what is needed is a guard rail safety bracket that may be inexpensively manufactured, that has flexibility in how it is attached to the substrate, and that, when incorporated into a temporary guardrail, will produce good resistance to forward and backward shear forces impinging on the guardrail.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a guardrail bracket is formed from a flat metal blank, such as one of steel. The bracket comprises a vertical triangular gusset plate having a horizontal margin, a vertical margin and a hypotenuse margin. A horizontally disposed base plate is joined to the horizontal margin of the gusset plate and extends therefrom in a transverse direction. At least one orifice is formed through the base plate and is adapted to receive a fastener for fastening the base plate to a substrate. The bracket further has a vertical plate joined to the vertical margin of the gusset plate and extends therefrom in the transverse direction. A sloping plate is joined to the hypotenuse margin of the gusset plate and extends therefrom in the transverse direction. A top end of the sloping plate is spaced from the first vertical plate so as to accommodate the insertion of at least one guardrail upright between the first vertical plate and the sloping plate.

In one embodiment, the base plate is elongate in a longitudinal direction at right angles to the transverse direction. The at least one orifice in the base plate is a slot that is elongated in the longitudinal direction such that a fastener may be inserted through the slot at any of a plurality of positions along the slot. In one embodiment, there are two such slots, longitudinally spaced from each other, that receive respective fasteners.

In one embodiment, the bottom end of the sloping plate is spaced from the base plate so as to permit the insertion of a horizontally disposed base board. In this or another embodiment, the bottom end of the first vertical plate is upwardly spaced from the base plate so as to permit the nailing of a toe board to the vertical upright(s).

In one embodiment, the first vertical plate is disposed in a plane. A body of the base plate extends rearwardly from the plane, while a lip of the base plate extends forwardly from the plane. This lip is designed to fit underneath a toe board that is placed adjacent the first vertical plate.

According to another aspect of the invention, a guardrail bracket comprises a vertically disposed flat triangular gusset plate with a horizontal margin, a vertical margin and a hypotenuse margin. A horizontally disposed base plate extends in a transverse direction from the horizontal margin of the gusset plate. The base plate is elongated in a longitudinal direction at right angles to the transverse direction. A plurality of longitudinally aligned slots are formed through the base plate so as to respectively receive therethrough a fastener for fastening the bracket to a substrate. A first vertical plate of the bracket is joined only to the vertical margin of the gusset plate and extends therefrom in the transverse direction. A sloping plate is joined only to the hypotenuse margin of the gusset plate and extends therefrom in the transverse direction. A top end of the sloping plate is spaced from the first vertical plate so as to be adapted to receive therebetween at least one guardrail upright.

In one embodiment, the base plate has a first margin joined to the gusset plate and a second margin opposed to the first margin. A second vertical plate is joined only to the second margin of the base plate and upwardly extends therefrom in a plane parallel to the gusset plate. The second vertical plate is provided to prevent a twisting of the upright(s) around a vertical axis.

According to another aspect of the invention, a guardrail bracket comprises a vertically oriented gusset plate that has a bottom margin, a vertical margin and a third margin that is disposed at an angle to the vertical margin. A horizontally oriented base plate has a first margin joined to the bottom margin of the gusset plate and a second margin opposed to the first margin. At least one orifice is formed through the base plate and is adapted to receive a fastener for fastening the bracket to a substrate. A first vertical plate extends in the transverse direction from the vertical margin of the gusset plate. An elongate fourth plate extends in the transverse direction from the third margin of the gusset plate. A first end of the fourth plate is spaced from the first vertical plate by an upright opening, the upright opening adapted to receive at least one vertical upright of a guardrail.

According to a still further aspect of the invention, a guardrail comprises at least one upright. The guardrail further has a bracket with a vertically oriented triangular gusset plate with a vertical margin, a bottom margin and a hypotenuse margin. A horizontally oriented base plate of the bracket is joined to and extends from bottom margin of the base plate in the transverse direction. At least one orifice is formed through the base plate for receiving a fastener for attaching the base plate to a substrate. A first vertical plate of the bracket is joined to and extends in the transverse direction from the vertical margin of the gusset plate. The gusset plate extends in a rearward direction from the first vertical plate, wherein the rearward direction is at right angles to the transverse direction. A sloping plate of the bracket is joined to and extends in the transverse direction from the hypotenuse margin of the gusset plate. A top end of the sloping plate is proximate to the first vertical plate and remote from the base plate. Conversely, a bottom end of the sloping plate is proximate to the base plate and remote from the first vertical plate. The top end of the sloping plate is rearwardly spaced from the first vertical plate to define an upright opening. The at least one upright is closely received in the upright opening. The bottom end of the sloping plate is upwardly spaced from the base plate to define a base board opening. A base board is closely received in the base board opening and is disposed to be adjacent the base plate. Any shear force impinging on the at least one upright from a frontward direction opposed to the rearward direction will be transmitted by the sloping plate to the base board and the base plate. The sloping plate thus enhances the ability of the guardrail to resist such a shear force.

In any of the above embodiments, the fastener, which can be a lag screw, may be inserted through a respective hole in the base board, through the orifice in the base plate and into the substrate. In one embodiment, the orifice is a longitudinally oriented slot that permits the point of insertion for the screw to vary among a plurality of locations, so as to miss reinforcing bars and other critical structures in the substrate. In one embodiment, there are at least two such slots, longitudinally spaced from each other, that receive respective fasteners, the longitudinal locations of both of which may be varied to miss underlying structure.

In one embodiment, the base plate has a body and a lip forwardly extending from the body. The guard rail further includes a toe board that is placed transversely on top of the lip. In one embodiment, a bottom margin of the vertical plate is vertically spaced from the base plate to create a toe board fastening space, permitting one or more fasteners, such as screws or nails, to pass through the toe board fastening space and attach the toe board to the at least one upright.

In any of the above embodiments, the base board may be a standard 2×4 (1.5 in.×3.5 in.) piece of lumber. The at least one upright may be a pair of two uprights, both of which may be standard 2×4 lumber. The toe board may be a 2×4, 2×6, 2×8, etc. The upright and base board openings of the bracket may be dimensioned to closely receive these standard lumber sizes.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the invention and their advantages can be discerned in the following detailed description as read in conjunction with the drawings of exemplary embodiments, in which like characters denote like parts and in which:

FIG. 1 is a top rear left perspective view of a temporary guardrail according to the prior art;

FIG. 2 is a top rear left perspective view of a guardrail bracket according to the invention;

FIG. 2A is a perspective view of a frame of reference, aligned to the view of the guardrail bracket presented in FIG. 2;

FIG. 3 is a bottom left perspective view of the guardrail bracket shown in FIG. 2;

FIG. 4 is a top front left perspective view of the guardrail bracket shown in FIG. 2;

FIG. 5 is a plan view of a blank used to make the guardrail bracket shown in FIGS. 2-4, after cutting and drilling but before bending;

FIG. 6 is a top view of the guardrail bracket shown in FIG. 2;

FIG. 7 is a top front left perspective view of the guardrail bracket as being incorporated into a temporary guardrail structure;

FIG. 8 is a top rear left perspective view of the guardrail bracket and associated guardrail boards shown in FIG. 7;

FIG. 9 is a top rear left perspective view of the guardrail bracket and associated guardrail boards shown in FIG. 7; and

FIG. 10 is a schematic sectional view taken along Line 10-10 of FIG. 8.

DETAILED DESCRIPTION

FIG. 2A illustrates a frame of reference for the directions described herein, as oriented to the perspective view of a guardrail bracket 200 shown in FIG. 2. Direction 202 is a frontward direction and is disposed in a horizontal plane. Direction 204 is a rearward direction that is opposite direction 202. Directions 202 and 204 are parallel to a longitudinal axis 206. A transverse axis 208 is horizontal and is disposed at right angles to axis 206; a “transverse direction” or a “left” or “right” direction, will all be parallel to axis 206. The transverse direction will roughly be in the plane of the guardrail. A vertical axis 210 is at right angles to axes 206 and 208, and “upward” and “downward” denote directions in parallel to axis 210.

Referring to FIGS. 2-6, the guardrail bracket 200 advantageously may be formed from a single sheet or blank 212 of metal, such as ⅛ in. thick steel. A triangular gusset plate 214 in use is disposed in a plane aligned to axes 210 and 206. Gusset plate 214 has a vertical margin 216 that extends from a top end 218 to a bottom end 220. A horizontal or bottom margin 222 extends rearwardly from end or corner 220 to a rear end or corner 224. A hypotenuse margin 226 extends from top end or corner 218 to bottom/rear end 224. In the illustrated embodiment, margins 216, 222 and 226 are all straight, making it possible to bend the plates (described below) extending from such margins to respective planes each perpendicular to the plane occupied by gusset plate 214. Margins 216 and 222 may each be about 12 inches long, and the angle between margin 226 and margin 216, and the angle between margin 226 and margin 222, may each be about 45 degrees.

As seen FIG. 5, a base plate 228 is attached by a bending fillet 230 to horizontal margin 222. The fillet 230, and the other bending fillets described herein may be about ⅛ in. wide and its width will vary as a function of the thickness of the metal plate used. The base plate 228 may be rectangular in shape and may be about 3½ in. wide, to match the width of standard 2×4 lumber (3.5 in.) A body 232 of the base plate 228 may be longer than it is wide, and may extend for the entire length of margin 222. A lip 234 of the base plate 228 forwardly extends from base plate body 232 and may be about 1.5 in. thick, matching the thickness of a toe board, which can be fabricated of 2×4, 2×6, 2×8, etc. lumber. A front margin 235 of the lip 234 may have rounded corners.

Base plate 228 may have a free longitudinal margin 236 that is parallel to and opposed to margin 222. At least one orifice, and in the illustrated embodiment two slots 238 and 240, are formed through the base plate 228. The slots 238 and 240 are longitudinally spaced from each other and their width is chosen so as to accept respective fasteners therethrough. These fasteners may be lag screws and are screwed into the substrate, which may be concrete, plywood or both. The fasteners alternatively could be bolts, nails or other fasteners. The base plate 228 has slots 238 and 240 so that the longitudinal position of the lag screws or other fasteners may be varied. This is a problem with temporary guard rails at construction sites: if each guardrail bracket or shoe has only fixed locations for the attaching screws, at some bracket/post locations the screws may damage structure underneath the substrate surface, such as reinforcing bar. Such damage may require the entire concrete section in which the rebar has been placed to be removed and redone.

The slots 238 and 240 may be positioned midway between fillet 230 and margin 236. The lip 234 may have a further, auxiliary fastener hole 241.

A plate 242 is joined to gusset plate vertical margin 216 by a bending fillet 244. Plate 242 may be rectangular and have a length in a vertical direction of about 8 in., and a width of about 3.375 in., this last dimension (in combination with the thickness of gusset plate 214) is selected to match the width of a standard 2×4. Plate 242 is connected to the rest of bracket 200 only by bending fillet 244. Plate 242 has nail holes 246 and 248 located at about the transverse center of plate 242. The nail holes 246, 248 are adapted to receive 8d or 16d nails which will be used to attach the bracket 200 to the uprights, described below (see FIG. 10). A lower margin 250 of plate 242 is spaced from base plate 232 by a vertical distance, such as about 4 inches. This permits any toe board to be nailed through this space into a front upright.

A sloping plate 252 is joined only to the hypotenuse margin 226 of the gusset plate 214 by a bending fillet 254. A width of plate 252 from the fillet 254 to a free margin 256 of the plate 252 is less than the width of base plate 228. The width of sloping plate 252 may, for example, be 1⅝ in. Plate 252 may be rectangular. A top end 258 of the sloping plate 252 is longitudinally spaced from gusset vertical margin 216 by a width chosen to be a little more than the longitudinal dimension of the upright posts used to make the guardrail. Where two standard 2×4 boards are used to make up the post or stanchion, and where they are positioned as shown in FIGS. 7-10, the longitudinal space between end 258 (after bending) and margin 216 should be a little more than 3 inches.

A bottom end 260 of the sloping plate 252 may, after bending, be vertically spaced from base plate 228 by an amount sufficient to accommodate a base board. Where the base board is made of standard 2×4 lumber, this spacing should be about 1.56 inches, or alternatively a little more than 1.5 inches.

The gusset plate 214 is furnished with nail holes 262 and 264 for receiving nails that, in the illustrated embodiment, will be driven into a rear one of two uprights (upright 804 in FIGS. 7-10). Where the uprights are standard 2×4 lumber, the nail holes 262 and 264 may be rearwardly spaced about 2¼ in. from vertical margin 216. Gusset plate 214 further has nail holes 266 and 268 that receive nails for driving into a base board. Where the base board is fashioned of standard 2×4 lumber, nail holes 266 and 268 may be upwardly spaced from bottom margin 222 by about ¾ in.

In one embodiment, a fifth plate 270 is attached only to base plate 228 by a bending fillet 272. Fifth plate 270, which will become a second vertical plate in a plane parallel to gusset plate 214, may be rectangular and may have a longitudinal dimension of about 3 inches and a width, from fillet 272 to a free end 274, of about 2⅛ in. A front end 276 of the plate 270 will be coplanar with vertical margin 216. A front nail hole 278 and a rear nail hole 280 are provided so that, after plate 270 is bent into a vertical disposition, nails may be respectively driven through hole 278 into a front upright 802 and hole 280 into a rear upright 804 (FIG. 9).

The bracket 200 is thus composed of five plates. Plates 228, 242 and 252 are connected to gusset plate 214 by linear fold lines or fillets, and therefore these plates may be bent by ninety degrees in a predetermined transverse direction, such as transversely right as seen in FIGS. 2-4. Alternatively, a bracket that is a mirror image of the bracket 200 could be formed by bending plates 228, 242 and 252, out of the plane occupied by gusset plate 214, leftward by ninety degrees. Plates 242 and 252 are only connected to gusset plate 214. Base plate 228 is connected only to gusset plate 270 and plate 270. By being bent vertically upward, the plate 270 becomes a second vertical plate which will reside in a plane parallel to gusset plate 214. Plate 270 is only connected to base plate 228.

After these four bending steps, the bracket 200 takes the form seen in FIGS. 2-4 and 6. Plate 242 occupies a vertical plane at the front of the bracket 200. Only the base plate lip 234 extends beyond it. Base plate 228 becomes a horizontal, bottom or floor plate. An upright opening 300 is defined by first vertical plate 242, gusset plate 214 and top edge 258 of sloping plate 252. A base board opening 302 is defined by gusset plate 214, bottom edge 260 of sloping plate 252 and base plate 228. An opening 304 is defined by lower margin 250 of the front vertical plate 242 and base plate 228. The opening 304 is a toe board fastening space. One or more nails or other fasteners (such as screws) may be driven or passed through a toe board, through space 304, and into an upright board such as upright 804.

FIG. 6 is a top view of the bracket 200 after it has been formed. The width of sloping plate 252 has been reduced such that its free margin 256 does not completely occlude the slot 238, 240 beneath it. The limited width of sloping plate 252 permits access by nut driver to the hex head lag screws typically used to affix the base plate 228 to the substrate 102.

FIGS. 7-10 are views of a segment of a guard rail 700, as incorporating a guard rail bracket 200 according to the invention. In the illustrated embodiment, a post or stanchion 800 is made up of a front 2×4 upright 802 and a rear 2×4 upright 804. In other embodiments a single 2×4 upright could constitute post 800, but in these other embodiments, the upright opening would be sized to closely fit such a single 2×4. In the illustrated embodiment, uprights 802 and 804 have been dropped through upright opening 300, such that their bottom ends will rest on base plate 228. Nails (not shown) are driven through gusset nail holes 262 and 264 into rear upright 804. A base board 100 is inserted through base board opening 302 to be disposed on top of base plate 228, as seen in FIG. 10. Lag screws 806, 808 are inserted through washers 810, 812, through drilled holes 814, 816 in the base board 100, and through the respective slots 238, 240 in base plate 228 and then into the substrate 102. Nails (not shown) may be driven through gusset plate nail holes 268 and 266 to even more firmly attach base board 100 to bracket 200.

Nails (not shown) are driven through first vertical plate nail holes 246, 248 into front upright 802 and through rear upright 804 (if 16d nails are used; alternatively 8d nails could be used). As shown in FIG. 9, nails (not shown) are respectively driven through second vertical plate nail hole 278 into front upright 802, and through second vertical nail hole 208 into rear upright 804.

A toe board 112 may be oriented transversely and placed on top of lip 234 and adjacent vertical plate 242. Nails (not shown) may be driven through toe board 112, through the space 304 below vertical plate margin 250, and into front upright 802. After assembly of the front and rear uprights 802, 804 to the bracket 200, a top rail 110 and a middle rail 108 may be nailed to the uprights 802, 804.

In an alternative embodiment, front and rear uprights 802, 804 may be turned 90 degrees so that they become left and right uprights, with their 3.5 in. widths then being longitudinally aligned. In this alternative embodiment, the horizontal dimension of the upright opening 300 is altered to be a little more than 3.5 in., and the positions of various nail holes in the plates are changed.

A guardrail as thus incorporating a guard rail bracket at each post location will have enhanced resistance to shear forces, particularly a shear force from a rearward direction or from a frontward direction. A shear force from a rearward direction will be resisted by first vertical plate 242. A shear force from a frontward direction will be resisted by sloping plate 252, and/or will be transmitted by sloping plate 252 to the base board 100 that has been closely fitted into opening 302. If the force from a frontward direction impacts on a member to the left (in FIG. 8) of sloping plate 252, the uprights 802 and 804 will have a tendency to twist. Since the uprights 802, 804 are rectangular in section, this twisting torque will be resisted by the interaction of their corners with second vertical plate 270.

A temporary guardrail built per FIGS. 7-10 has been tested for resistance to shear force coming from either the frontward or the rearward direction. It has been found to resist a shear force of 300 pounds, from either such direction, as applied at a point 42 inches above plate 228, without failure.

In summary, a guardrail bracket has been illustrated and described which is fashioned from a single metal plate and which contributes greatly enhanced resistance to shear forces on temporary guardrails built with it. Slots in the base plate of the bracket permit the location of affixing lag screws to be altered so as to avoid underlying structures.

While illustrated embodiments of the present invention have been described and illustrated in the appended drawings, the present invention is not limited thereto but only by the scope and spirit of the appended claims.