US 3499630 A
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March 1-0, 1970 J. c. o sl-uo 7 ,4 ,6
v POSTS FOR HIGHWAY SAFETY RAILS Filed May 7, 1968 v s Sheets-Sheet 1 INVENTOR. f 1 v 7 JOHN C. D/ISI/ld March 10, 1970 C.'DASHIO 3,499,630
' POSTS FOR HIGHWAY SAFETY RAILS Filed May 7, 1968 s Sheets-Sheet 2 f l o 3 D V Q .5. 3 m m INVENTOR. JOHN C DASHIO March 10, 1970 =-J.-c. DASHIO 3,499,630.
POSTS FOR HIGHWAY SAFETY RAILS Filed May 7. 1968 3 Sheets-Sheet 5.
INVENT OR. J0 HN C. D4 SIIIO BY m4,
United States Patent U.S. Cl. 25613.1 Claim ABSTRACT OF THE DISCLOSURE Posts for individual use such as stop signs, street signs, street lighting, post and guard rail supports having a shearing coupling for joining to a ground support, the shearing coupling being provided with a shearing section shaped to permit a limited amount of bending movement while being sheared and which, upon impact, will provide spaced abutments which will shear off by impact and maintain the post in a vertical position, the shearing coupling being preferably of V shape that extends inwardly from the outer periphery of the coupling to provide a reduced shearing area in the center of the coupling.
CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of co-pending application Ser. No. 526,514 filed Feb. 10, 1966, now abandoned.
STATE OF THE ART Shearing couplings heretofore suggested for hydrants, safety rail structures or the like, consist ofbreakable rings or plugs having a reduced cross section or groove either internally of the shearing ring or externally of the shearing plug. All of such structures cause the post or hydrant to be bent horizontally with the road surface.
DISCLOSURE The invention will become more apparent from a consideration of the drawings constituting a part hereof in which like reference characters designate like parts and in which:
FIGURE 1 is a side elevational view, partially in cross section, of portions of a ground support and guard rail posts with a shearing coupling therebetween, embodying the principles of this invention;
FIGURE 2 is a similar view of a modified form of fastening of the shearing coupling and ground support; FIGURE 3 a top plan view of a shearing coupling;
FIGURE 4 an exploded view of the parts of the coupling and anchor and posts with the coupling shown in cross section;
FIGURE 5 is a side elevation of a guard rail and post before shearing;
FIGURE 6 a similar view of the rail post partially sheared;
FIGURE 7 a similar view with the post sheared from the ground support;
FIGURE 8 a view showing the guard rail cable supporting the posts in a vertical position after it is completely sheared from its support;
FIGURES 9, 10 and 11 are top plan views diagrammatically illustrating contact of a vehicle with the safety rail; and,
FIGURE 12 a view in perspective diagrammatically illustrating collision of 'a vehicle with the safety rail after the supporting posts have been sheared off.
In the drawing, the numeral 1 is a guard rail post having a flange 2, the numeral 3 is a ground support having a flange 4, and intermediate flanges 2 and 4 is a shearing "ice coupling generally designated by the numeral 6 having flanges 7 and 8.
As shown in FIGURE 4, the shearing coupling 6 is of V-shape and the flange 8 is recessed to receive the heads 9 of connecting bolts 10. The flange 7 of the shearing coupling has threaded bolt holes 11 for receiving the threaded ends of bolts 12, the shearing coupling of FIG- URE 4 being shown assembled to the post 1 and ground support in FIGURE 2 of the drawings.
In FIGURE 1, the bolts are not recessed in the flange of the shearing coupling, but sufiicient space is shown between the head 9 of the connecting bolts and the upper flange 7 of the shearing coupling to permit the post 1 to collapse in the direction of an impact force. When the juxtaposed flanges abut, the impact force will react to shear off the post and cause it to be suspended in a vertical position.
In FIGURE 5, the guard rail post 1 is shown when subject to impact by a vehicle designated by the reference character (A) which abuts the rails shown as steel cables designated by the reference character (B), there being three cables shown in vertical spaced relation mounted on the post. As the vehicle collides with the steel cable, the impact will shear off the post 1 which is shown in a tilted position in FIGURE 6 with the upper flange 7 of the shearing coupling resting on the lower flange 8. When the rail post 1 is completely sheared off, which results from the impact of the upper flange 7 with the lower flange 8 or the upper flange 7 with the bolt heads 9 of FIGURE 1, the safety rail post will assume a vertical position in which it is held suspended by the steel cable.
As shown in FIGURE 6, a number of rail posts may be sheared off, depending on the mass and force of the impacting vehicle; thus in the center view of FIGURE 6, two posts are shown sheared off, and in the top view of FIGURE 6, three posts are shown as sheared Off.
With reference to FIGURE 7, the vehicle is shown leaving the road and striking the guard rail. Then it drags the guard rail with it shearing off three posts and ending up with six posts shown sheared off from their ground supports. Because of the V-shaped shearing section and the clearance between the flanges of the V coupling, the rail posts do not bend but shear oif clean along their entire shearing area by impact of the abutting flanges and retain their vertical position, which constitutes the guard rail cables a net for enmeshing the vehicle and prevent its tumbling over the rail as it would do if the rail posts were bent and not sheared off straight. The same shearing action would result if the posts were single members and not interconnected by guard rails, as for example, a stop sign on a highway. If the stop sign has the V-shaped coupling, it will shear off and retain its vertical position when moving ofl? of its ground support. It would fall in the direction of movement of the vehicle and reduce the amount of physical damage that would result to the vehicle if the stop sign post was bent over parallel with the ground instead of shearing.
The collision of the flanges 7 and 8 of the shearing coupling causes a reflecting action shearing off outwardly to enmesh the vehicle. This is an important safety factor which will save livesand reduce property damage. If the cable and posts were not retained in a vertical position, the combined cable could not absorb the initial shock of the vehicle and bring it to a halt. Safety guard rails with connecting steel cables presently in use have a pre-- dominant failure of collapsing parallel with the ground and the cables are practically useless, as under such conditions the vehicle would overrun the barricade or be deflected back into the line of traffic.
The shearing coupling can be strengthened or weakened,
cross-sectional area of the shear point, which is at the reduced portion of the V coupling. The included angle of the V-shaped notch should be such as to provide suflicient clearance to permit the rail post to collapse on impact and transmit the impact force to the remaining unsheared portion through the juxtaposed flanges when they come in contact.
Although one embodiment of the invention has been herein illustrated and described, it will be evident to those skilled in the art that various modifications may be made in the details of construction without departing from the principles herein set forth.
1. A plurality of columns each of which comprises a ground support section, a post supported thereon, and a shearing coupling disposed therebetween, the bottom of said post and the top of said ground support section being provided with flanges adapted to engage flanges formed on said shearing coupling, means for attaching said flanges of said shearing coupling to said flanges of said post and ground support section, said shearing coupling having an axially extending central opening and a V-shaped annular groove in the outer periphery thereof, with the bottom of said groove terminating relatively adjacent said central opening thereby to define a restricted shearing section between said ground support and said post, the included angle of the said V-shaped groove being such as to provide sufiicient space for angular movement of the post to allow it to collapse with sufficient force to shearofl along the entire shearing area of said coupling when the juxtaposed faces of the V-shaped groove collide, means secured to and extending between said posts for interconnecting the same, each of said posts when sheared being retained by said interconnecting means in a substantially vertical position thereby to form a means adapted to absorb the force of the object causing such shearing.
References Cited UNITED STATES PATENTS 1,883,467 10/1932 Banks 2853 X 1,944,777 1/1934 Banks 287-108 2,085,074 6/1937 Boyles 287-108 2,337,626 12/1943 Sawyer 25613.1 3,307,833 3/1967 Muller et al 52296 3,349,531 10/1967 Watson 52296 DENNIS L. TAYLOR, Primary Examiner US. Cl. X.R. 5298