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History Of Strength Of Materials, With a brief account of the history of theory of elasticity and theory of structures, by Stephen Timoshenko, Dover Publications, reprint 1983, originally published McGraw-Hill, 1953
Federal Highway Administration (FHWA) Memorandum document, dated Sep. 3, 1993, “Subject: ACTION: Breakaway Sign Supports”
Joint Committee of the American Association of State Highway and Transportation Officials (AASHTO), the Associated General Contractors of America (AGC) and the American Road and Transportation Builders Association (ARTBA), Subcommittee on New Highway Materials, Task Force 13 Report, “A Guide to Small Sign Support Hardware”, June 1998.
National Cooperative Highway Research Program Report 350, entitled “Recommended Procedures for the Safety Performance Evaluation of Highway Features”, 1993. National Cooperative Highway Research Program Report 471, entitled “Evaluation of Roadside Features to Accommodate Vans, Minivans, Pickup Trucks, and 4-Wheel Drive Vehicles”, 2002.
1. Field of the Invention
The present invention may be considered a Gating Impact Attenuator Decelerator (GIAD), as defined by the National Cooperative Highway Research Program (NCHRP) Report 350 (350) and/or the European Union highway safety design specification known as EN1317 (EN1317), for use as a stand-alone highway safety device or in conjunction with other highway safety devices.
2. Background of the Invention
The present invention relates primarily to highway safety devices, secondarily to on-board vehicle mounted safety devices and more particularly to enhancing the performance of such devices when occupants of vehicles are subjected to severe deceleration forces.
The present invention utilizes the general statement that highway vehicles tend to exhibit higher roadway clearance as their mass increases. That is, pickup trucks weight more than small cars and also have higher centers-of-mass than small cars.
The present invention utilizes the kinetic-energy absorbing nature of existing “breakaway” highway safety equipment, as per the present inventor's issued U.S. patent devices such as U.S. Pat. Nos. 6,367,208; 6,454,488 and 6,502,805, and others, with enhanced dynamic deflection which occurs when such devises are impacted by highway vehicles, to cause to have rotation of the “breakaway” features so as to alter the amount of kinetic-energy absorbed based on the elevation of the impacting vehicle's bumper height. That is, the present invention counters the natural result of the larger moment, and therefore small amount of energy required, to “break-off” a “breakaway” highway safety device impacted by a pickup truck vs a small car. As such, the present invention provided for a higher kinetic-energy absorption when hit by a pickup truck than when hit by a small car. This aspect allows the same device, on impact, to decelerate vehicles, of different mass, traveling at the same speed, based on the assumption that the heavier vehicle will have higher bumper height.
The present invention also addresses the natural positive vertical vector developed by highway vehicles impacting present art “breakaway” highway safety devices and the resulting instability associated with such vehicle “launches”.
For illuminating purposes, specific examples of the economic aspects of the present invention may be seen in current market prices for a number of, in wide current use, physical manifestations of issued U.S. patent devices for what is commonly known as highway guardrail end terminals conforming to NCHRP 350, Chapter 2, Section 188.8.131.52, “Terminals and Crash Cushions” & Chapter 3, Section 3.2.2 “Terminals and Crash Cushions” with specific reference to Table 3.7, “Nominal impact severity values and tolerances for terminals and crash cushions” Said, in wide current use, patented devices include “box beam guiderail end terminals”, and “w-beam guardrail end terminals”. Current prices for such devices are available thru such government agencies such as individual State Departments of Transportation. An example is the information from the New York State Department of Transportation Regional and Statewide Weighted Average Awarded Prices Contracts Let Jul. 1, 2004 to Jun. 30, 2005 (Revised Oct. 27, 2005) report from which three (3) such aforementioned patented device(s) prices can be discerned: “ITEM 606.1203, BOX BEAM END ASSEMB, TYPE III”, with an avg. awarded price of $3,768.03 ea., “ITEM 606.34 15 END TERMI HVY POST B-OUT C.GRAL,ET 2000+”, with an avg. awarded price of $5,400.00 ea., and “ITEM 606.4650 CRSH-CUSH ATTEN TERMINAL 350, CAT 350RU”, with an avg. awarded price of $6,332.90 ea.
Drafts of expected update changes to NCHRP Report 350 include increased mass and higher elevation, from travelway pavement, of vehicle center-of-mass of the “pick-up truck” test vehicle. Such increases in test vehicle(s) result in both higher kinetic-energy-management requirements and higher bending moment loads at groundline. Such changes will result in most presently-in-use NCHRP Report 350 rated End Terminal and Crash Cushion installations to be considered, by U.S. transportation agencies, obsolete. Examples of issued U.S. Patented devices, which are or will soon be “off-patent”, and which have been successfully reduced to practice and in wide use on the U.S. National Highway System, are:
U.S. Pat. No. 4,407,484, “Impact energy absorber”, issued Oct. 4, 1983, to Meinzer.
U.S. Pat. No. 4,655,434, “Energy Absorbing Guardrail Terminal” issued Apr. 7, 1987, to Bronstad,
U.S. Pat. No. 4,678,166, “Eccentric Loader Guardrail Terminal”, issued Jul. 7, 1987, to Bronstad et al.
U.S. Pat. No. 4,784,515, “Collapsible highway barrier”, issued Nov. 15, 1988, to Krage et al.
U.S. Pat. No. 4,838,523, “Energy absorbing guard rail terminal”, issued Jun. 13, 1989, to Humble et al.
U.S. Pat. No. 4,844,213, “Energy absorption system”, issued Jul. 4, 1989, to Travis.
U.S. Pat. No. 4,928,928, “Guardrail extruder terminal”, issued May 29, 1990, to Buth et al.
U.S. Pat. No. 5,022,782, “Vehicle crash barrier”, issued Jun. 11, 1991, to Gertz et al.
U.S. Pat. No. 5,078,366, “Guardrail extruder terminal”, issued Jan. 7, 1992, to Sicking et al.
U.S. Pat. No. 5,217,318, “Low maintenance crash barrier for a road divider”, issued Jun. 8, 1993, to Peppel.
U.S. Pat. No. 5,348,416, “Gandy dancer: end piece for crash cushion or rail end treatment”, issued Sep. 20, 1994, to Ivey et al.
U.S. Pat. No. 5,391,016, “Metal beam rail terminal”, issued Feb. 21, 1995, to Ivey et al.
(Paraphrasing U.S. Pat. No. 2,375,443 to Sarchet, col. 1, line 24) Having in mind the deflects of the prior art, it is an important object of this invention to provide a decelerating mechanism for vehicles that is not complicated in construction or operation and which may be produced and used at low cost.
Another object of the invention is the provision, in a vehicle deceleration mechanism, of sequentially operable forces to be applied periodically to a vehicle to decelerate without undue forces in a destructive manner.
Another object of the invention is to provide a friction reducing surface on a U.S. Pat. No. 3,881,697 issued May 6, 1975 to Glaesener ('697) type post (Paraphrasing U.S. Pat. No. 3,519,249 to Nave, col. 2, line 6) “ . . . in the event of an impact of a vehicle . . . ”
My numerous experiments have yielded a number of discoveries in large part because the present art teaches away from the claimed range of the present invention. As evidence of unexpected results, the record shows no present art device so configured to be tested as anything other than a “breakaway” device, unlike the present invention's tests, utilizing lower yield steel, and configured as a gating-impact-attenuator. The prior art is so deficient of the present invention's unexpected properties that there was no motivation to make what might otherwise appear to be obvious composition changes. The present invention's unexpected results show the significant difference-in-kind over present art gating-impact-attenuator devices. The comparison of test data shows that the claimed construction possess unexpectedly improved properties that the prior art does not have. Nothing in the present art suggests the use of lower yield, less expensive steel in lieu of the present art very high strength steel. The present invention's use of less brittle steel allows greater rotation before the on-set of structural failure.
The present invention's breakaway hardware geometry allows said hardware to “rockaway” or rotate to its “racked” position before the breakaway hardware is fully loaded so that the breakaway hardware is primarily in tension which results in greater load carrying capacity, and thereby changing its structural failure due to the higher vehicle bumper height.
Use of very high speed digital cameras, in my latest tests, (see FIGS. 69-77, with summary statements FIGS. 67 & 78) captures the greater rotation for the lower strength but less brittle steel breakaway hardware. The greater rotation of the lower strength, less brittle, steel breakaway hardware results in greater tensile-to-shear ratio at structural failure, due to the applied service load(s) which generates higher breakaway strength.
In combination with the abovementioned unexpected advantages gained via the discovers via the use of lower yield breakaway steel with less stiff upper post section allows even greater rotation of breakaway hardware before the on-set of service load(s) on the breakaway hardware.
Steel is usually thought of as a ductile material. When loaded to failure, steel usually exhibits significant deformation. High deformation, in steel, usually consists of the mircostructure's grains failing thru void-formations resulting from flows around harder particles in the mircostructure. This characteristic behavior causes the steel to absorb very high quantities of imposed energy. Such characteristics are almost always twinned to the material characteristic known as “toughness”.
Steel, as a general statement, particularly where the temperature of the material in question is considered a constant, tends to “trade” ductility and toughness for tensile strength. The higher the tensile strength, the lower the ductility and toughness. This behavior, at high tensile strengths is usually known as “brittle” behavior. Brittle behavior is usually exhibited by very little plastic deformation before structural failure. In brittle failure, instead of the microstructure's grains “flowing” and thereby opening up voids, usually “downstream” from individual “hard” particles, which are usually well distributed throughout the material's volume, the crystal planes defined by boundaries between individual grains fail. That is, structural failure is the breaking of the adhesive bonds holding individual grains to each other. The usually term for crystalline structural failure is “cleavage”. Unlike the “dimpling” breakage surfaces associated with ductile failure (usually providing a “dull” surface), cleavage break surfaces tend to be significantly “flat” (usually providing a “shiny” surface) and shows “deltas” or “arrowhead” formations which point in the direction of the fracture's origin or “start-point”. Crystalline structural failure, unlike ductile failure, usually absorbs very little energy.
In either type of structural failure mode, “ductile” or “brittle”, when dealing with steels, structural failure surfaces will usually, clearly, exhibit both ductile “dimpling” and brittle “cleavage” across the failed surface(s). It is usually the preponderance of “dimpling” or “cleavage” exhibited on a failure surface which allows the observer to characterize the structural failure mode as “ductile” or “brittle”.
Brittle failure, for a given temperature, in steels considered “ductile”, occur when said ductile steel's volume contains cracks pre-existing before the onset of the brittle failure. Such “cracks” tending to be load-concentrators.
For the structural applications of the present invention, as a general statement, for steel, an increase in “impact strength” and “ductility” usually means a decrease in “yield strength” and “tensile strength”. That is, to avoid structural failure, in a high energy impact, one would tend to choose a “soft” steel.
There is a long history of vehicle-mounted safety equipment intended to reduce harm and injury to vehicle occupants in the event of an impact or crash. A review of such in-vehicle impact safety equipment, limited for illustrative purposes to highway use motor vehicles, includes such prior art as:
U.S. Pat. No. 1,256,848 issued Feb. 19, 1918 to Uttz
U.S. Pat. No. 1,521,579 issued Dec. 30, 1924 to Freedman
U.S. Pat. No. 1,624,418 issued Apr. 12, 1927 to Marsh
U.S. Pat. No. 1,915,267 issued Jun. 27, 1933 to Bigelow
U.S. Pat. No. 2,050,141 issued Aug. 4, 1936 to Wethington
U.S. Pat. No. 2,180,912 issued Nov. 21, 1939 to Rogers
U.S. Pat. No. 2,477,933 issued Aug. 2, 1949 to Labser
U.S. Pat. No. 2,850,291 issued Sep. 2, 1958 to Ziccardi
U.S. Pat. No. 3,473,824 issued Oct. 21, 1969 to Carey et. al.
U.S. Pat. No. 3,495,675 issued Feb. 17, 1970 to Hass et. al.
U.S. Pat. No. 3,527,475 issued Sep. 8, 1970 to Carey et. al.
U.S. Pat. No. 3,552,769 issued Jan. 5, 1971 to Kemmerer et. al.
There is also a long history of safety equipment for stopping vehicles before such vehicles exit its appropriate channel of intended use. A review of such safety equipment includes such prior art as:
U.S. Pat. No. 61,548 issued Jan. 29, 1867 to Love
U.S. Pat. No. 197,248 issued Nov. 20, 1877 to Chace
U.S. Pat. No. 322,812 issued Jul. 21, 1885 to Ellis
U.S. Pat. No. 348,773 issued Sep. 7, 1886 to Ramsay
U.S. Pat. No. 363,438 issued May 24, 1887 to Trafton
U.S. Pat. No. 402,790 issued May 7, 1889 to Waterhouse
U.S. Pat. No. 498,215 issued May 23, 1893 to Poehlman
U.S. Pat. No. 524,416 issued Aug. 14, 1894 to Ewaldt
U.S. Pat. No. 537,621 issued Apr. 16, 1895 to Stanford
U.S. Pat. No. 555,273 issued Feb. 25, 1896 to Weber
U.S. Pat. No. 562,297 issued Jun. 16, 1896 to Haley
U.S. Pat. No. 581,185 issued Apr. 20, 1897 to Weber
U.S. Pat. No. 593,605 issued Nov. 16, 1987 to Pearson
U.S. Pat. No. 609,159 issued Aug. 16, 1898 to McMahon
U.S. Pat. No. 618,460 issued Jan. 31, 1899 to Haskell
U.S. Pat. No. 630,577 issued Aug. 8, 1899 to Westmeyer
U.S. Pat. No. 676,630 issued Jun. 18, 1901 to McCord
The prior art transition from the above U.S. patents, which focused primarily on railroad applications, to roadway sited devices intended for safely stopping errant highway cars and trucks begins with patents such as:
U.S. Pat. No. 1,551,556 issued Sep. 1, 1925 to Gust
U.S. Pat. No. 1,808,767 issued Jun. 9, 1931 to De Gloria et. al.
U.S. Pat. No. 2,000,974 issued May 14, 1935 to Mead
U.S. Pat. No. 2,088,087 issued Jul. 27, 1937 to Hudson
U.S. Pat. No. 2,091,925 issued Aug. 31, 1937 to Heltzel
U.S. Pat. No. 2,146,445 issued Feb. 7, 1939 to Russert et. al.
U.S. Pat. No. 2,154,818 issued Apr. 18, 1939 to Mayer
U.S. Pat. No. 2,776,116 issued Jan. 1, 1957 to Brickman
U.S. Pat. No. 3,141,655 issued Jul. 21, 1964 to Platt
U.S. Pat. No. 3,503,600 issued Mar. 31, 1970 to Rich
The above devices tended to fall out of favor beginning with the federal institutionalizing of the standard longitudinal W-beam (a.k.a. corrugated-beam) highway safety crash barrier in the later half of the 1950's, followed by the issuance of “Highway Research Correlation Services Circular 482” in 1962, followed by the issuance of National Cooperative Research Program (NCHRP) Report 153 (153) in the early 1970's. Such federally suggested design guidelines encouraged innovation in the design and testing of highway W-beam guardrail end terminals which was expressed with the issue of such patents such as:
U.S. Pat. No. 3,606,258 issued Sep. 20, 1971 to Fitch
U.S. Pat. No. 3,643,924 issued Feb. 22, 1972 to Fitch
U.S. Pat. No. 3,672,657 issued Jun. 27, 1972 to Young, et. al.
U.S. Pat. No. 3,845,936 issued Nov. 5, 1974 to Boedecker, Jr. et al.
U.S. Pat. No. 3,876,185 issued Apr. 8, 1975 to Welch
U.S. Pat. No. 3,880,404 issued Apr. 29, 1975 to Fitch
U.S. Pat. No. 3,881,697 issued May 6, 1975 to Glaesener ('697)
“Roadside safety apparatus”, Current U.S. Class: 256/13.1
U.S. Pat. No. 3,944,187 issued Mar. 16, 1976 to Walker “Roadway impact attenuator”, Current U.S. Class: 256/13.1; 188/377; 256/1
U.S. Pat. No. 4,007,917 issued Feb. 15, 1977 to Brubaker
“Structures for absorbing impact energy”, Current U.S. Class: 256/13.1; 404/6; 428/312.6; 428/312.8; 428/319.7
U.S. Pat. No. 4,047,701 issued Sep. 13, 1977 to Glaesener ('701)
“End assembly for roadway guard rail”, Current U.S. Class: 256/13.1
U.S. Pat. No. 4,290,585 issued Sep. 22, 1981 to Glaesener ('585)
“Vehicle-stopping device for safety barriers”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 4,407,484 issued Oct. 4, 1983 to Meinzer
“Impact energy absorber”, Current U.S. Class: 256/13.1; 104/256; 114/219; 404/6
The economic viability of the abovementioned prior art was diminished with the issuance of National Cooperative Research Program (NCHRP) Report 230 (230) in the early 1980's. Highway safety standards expressed in NCHRP 230 re-engaged and encouraged innovation. Some examples of such innovation are:
U.S. Pat. No. 4,655,434 issued Apr. 7, 1987 to Bronstad
“Energy absorbing guard rail terminal”, Current U.S. Class: 256/13.1; 403/2
U.S. Pat. No. 4,678,166 issued Jul. 7, 1987 to Bronstad et. al
U.S. Pat. No. 4,784,515 issued Nov. 15, 1988 to Krage et al.
U.S. Pat. No. 4,838,523 issued Jun. 13, 1989 to Humble et. al.
“Energy absorbing guard rail terminal”, Current U.S. Class: 256/13.1; 248/66; 403/2
U.S. Pat. No. 4,928,928 issued May 29, 1990 to Buth et. al.
“Guardrail extruder terminal”, Current U.S. Class: 256/13.1; 188/377; 256/19; 404/6
U.S. Pat. No. 5,022,782 issued Jun. 11, 1991 to Gertz et al.
U.S. Pat. No. 5,078,366 issued Jan. 7, 1992 to Sicking et al.
“Guardrail extruder terminal”, Current U.S. Class: 256/13.1; 188/377; 256/19; 404/6
U.S. Pat. No. 5,217,318 issued Jun. 8, 1993 to Peppel
Such innovation was tempered by the knowledge that NCHRP 230 would be superseded, which it was by NCHRP 350. NCHRP 350 provided significantly more specific design standards for many highway safety devices. The market responded to said specific government standards producing the available present day art highway safety devices, some of which are expressed in such issued patents shown below. The present invention provides novel, not apparent improvements on these and similar patented devices and similar open-art devices:
U.S. Pat. No. 5,391,016 issued Feb. 21, 1995 to Ivey et al.
“Metal beam rail terminal”, Current U.S. Class: 404/6; 256/13.1; 403/377; 403/383; 403/DIG.3; 404/11
U.S. Pat. No. 5,407,298 issued Apr. 18, 1995 to Sicking et al.
“Slotted rail terminal”, Current U.S. Class: 404/6; 256/13.1
U.S. Pat. No. 5,660,496 issued Aug. 26, 1997 to Muller at al.
U.S. Pat. No. 5,765,811 issued Jun. 16, 1998 to Alberson et al.
“Guardrail terminal”, Current U.S. Class: 256/13.1; 256/65.01
U.S. Pat. No. 5,775,675 issued Jul. 7, 1998 to Sicking et al.
“Sequential kinking guardrail terminal system”, Current U.S. Class: 256/13.1; 256/65.01
U.S. Pat. No. 5,860,253 issued Jan. 19, 1999 to Lapointe
“Collapsible post structure”, Current U.S. Class: 52/98; 248/548; 248/900; 403/2; 403/297; 403/362; 52/726.3; 52/726.4; 52/736.1
U.S. Pat. No. 5,868,521 issued Feb. 9, 1999 to Oberth, et. al.
“Highway crash cushion and components thereof”, Current U.S. Class: 404/6; 256/13.1; 428/911
U.S. Pat. No. 5,957,435 issued Sep. 28, 1999 to Bronstad “Energy-absorbing guardrail end terminal and method”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 5,967,497 issued Oct. 19, 1999 to Denman, et al.
“Highway barrier and guardrail”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 6,022,003 issued Feb. 8, 2000 to Sicking et al.
“Guardrail cutting terminal”, Current U.S. Class: 256/13.1; 256/17; 256/59; 404/10; 404/6; 404/9
U.S. Pat. No. 6,089,782 issued Jul. 18, 2000 to Bligh, et al.
“Frame catcher adaptation for guardrail extruder terminal”, Current U.S. Class: 404/6
U.S. Pat. No. 6,109,597 issued Aug. 29, 2000 to Sicking, et al.
“Anchor cable release mechanism for a guardrail system”, Current U.S. Class: 256/13.1; 248/548; 248/900; 256/1; 404/6
U.S. Pat. No. 6,129,342 issued Oct. 10, 2000 to Bronstad
“Guardrail end terminal for side or front impact and method”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 6,142,452 issued Nov. 7, 2000 to Denman, et. al.
“Highway barrier and guardrail”, Current U.S. Class: 256/13.1; 256/1; 404/6
U.S. Pat. No. 6,179,516 issued Jan. 30, 2001 to Ivey, et al.
“Pipe rack crash cushion”, Current U.S. Class: 404/6; 256/13.1; 404/9
U.S. Pat. No. 6,220,575 issued Apr. 24, 2001 to Lindsay, et al.
“Anchor assembly for highway guardrail end terminal”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 6,293,727 issued Sep. 25, 2001 to Albritton
“Energy absorbing system for fixed roadside hazards”, Current U.S. Class: 404/6; 256/13.1; 404/10
U.S. Pat. No. 6,299,141 issued Oct. 9, 2001 to Lindsay, et al.
“Anchor assembly for highway guardrail end terminal”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 6,398,192 issued Jun. 4, 2002 to Albritton
“Breakaway support port for highway guardrail end treatments”, Current U.S. Class: 256/13.1; 256/1; 256/DIG.5; 404/6
U.S. Pat. No. 6,409,417 issued Jun. 25, 2002 to Muller, et al.
“Safety road barrier end assembly with a gradual absorption of the impact energy”, Current U.S. Class: 404/6; 256/13.1
U.S. Pat. No. 6,435,761 issued Aug. 20, 2002 to Bligh et al
“Slot guard for slotted rail terminal”, Current U.S. Class: 404/6; 256/13.1; 404/9
U.S. Pat. No. 6,488,268 issued Dec. 3, 2002 to Albritton
“Breakaway support post for highway guardrail end treatments”, Current U.S. Class: 256/13.1; 403/2; 404/10; 404/6
U.S. Pat. No. 6,505,820 issued Jan. 14, 2003 to Sicking et al.
“Guardrail terminal”, Current U.S. Class: 256/13.1; 256/17; 256/59; 404/10; 404/6; 404/9
U.S. Pat. No. 6,536,985 issued Mar. 25, 2003 to Albritton
“Energy absorbing system for fixed roadside hazards”, Current U.S. Class: 404/6; 256/13.1; 404/10
U.S. Pat. No. 6,554,256 issued Apr. 29, 2003 to Ochoa
“Highway guardrail end terminal assembly”, Current U.S. Class: 256/13.1; 404/10; 404/6
U.S. Pat. No. 6,619,630 issued Sep. 16, 2003 to Albritton
“Breakaway support post for highway guardrail end treatments”, Current U.S. Class: 256/13.1; 256/1; 404/10; 404/6; 404/9
U.S. Pat. No. 6,715,735 issued Apr. 6, 2004 to Bligh et al.
“Head assembly for guardrail extruder terminal”, Current U.S. Class: 256/13.1; 404/10; 404/6
U.S. Pat. No. 6,719,483 issued Apr. 13, 2004 to Welandsson
“Collision safety device”, Current U.S. Class: 404/6; 256/13.1; 404/9
U.S. Pat. No. 6,783,116 issued Aug. 31, 2004 to Albritton
“Guardrail end terminal assembly having at least one angle strut”, Current U.S. Class: 256/13.1; 256/31
U.S. Pat. No. 6,793,204 issued Sep. 21, 2004 to Albritton
“Breakaway support post for highway guardrail end treatments”, Current U.S. Class: 256/13.1
U.S. Pat. No. 6,811,144 issued Nov. 2, 2004 to Denman, et al.
“Apparatus with collapsible modules for absorbing energy from the impact of a vehicle”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 6,854,716 issued Feb. 15, 2005 to Bronstad
“Crash cushions and other energy absorbing devices”, Current U.S. Class: 256/13.1
U.S. Pat. No. 6,886,813 issued May 3, 2005 to Albritton
“Breakaway support post for highway guardrail end treatments”, Current U.S. Class: 256/13.1
U.S. Pat. No. 6,902,150 issued Jun. 7, 2005 to Alberson, et al.
“Steel yielding guardrail support post”, Current U.S. Class: 256/13.1; 404/10; 404/6; 404/9
U.S. Pat. No. 6,948,880 issued Sep. 27, 2005 to Cincinnati
“Guardrail terminal”, Current U.S. Class: 404/6; 256/13.1; 404/10
U.S. Pat. No. 6,962,459 issued Nov. 8, 2005 to Smith, et. al.
“Crash attenuator with cable and cylinder arrangement for decelerating vehicles”, Current U.S. Class: 404/6; 256/13.1; 404/9
U.S. Pat. No. 6,997,637 issued Feb. 14, 2006 to Schneider, et al.
“Deceleration-limiting roadway barrier”, Current U.S. Class: 404/6; 244/110R; 256/13.1; 49/34
U.S. Pat. No. 7,059,590 issued Jun. 13, 2006 to Bronstad
“Impact assembly for an energy absorbing device”, Current U.S. Class: 256/13.1
U.S. Pat. No. 7,070,031 issued Jul. 4, 2006 to Smith et al,
“Apparatus for exerting a resisting force”, Current U.S. Class: 188/382; 256/13.1; 404/6
U.S. Pat. No. 7,090,428 issued Aug. 15, 2006 to Hinojosa
“Protector for safety rails”, Current U.S. Class 404/6; 256/13.1; 404/9; 52/736.4
U.S. Pat. No. 7,100,752 issued Sep. 5, 2006 to Reid, et al.
“Bridge pier crash cushion system”, Current U.S. Class: 188/371; 188/377; 256/13.1; 404/6
U.S. Pat. No. 7,100,903 issued Sep. 5, 2006 to Wilson
“Impact barrier system”, Current U.S. Class: 256/13.1; 404/10; 404/6; 404/9
U.S. Pat. No. 7,111,827 issued Sep. 26, 2006 to Sicking et al.
“Energy-absorption system”, Current U.S. Class: 256/13.1; 256/17; 256/59; 404/10; 404/6; 404/9
U.S. Pat. No. 7,125,197 issued Oct. 24, 2006 to Krewsun et al.
“Method and apparatus for a minimally aggressive vehicle stopping system”, Current U.S. Class: 404/6; 256/13.1; 49/49; 49/9
U.S. Pat. No. 7,182,320 issued Feb. 27, 2007 to Heimbecker et al
“Integrated cable guardrail system”, Current U.S. Class: 256/13.1; 404/6
U.S. Pat. No. 7,185,882 issued Mar. 6, 2007 to Buth et al
“Box beam terminals”, Current U.S. Class: 256/13.1; 248/66
U.S. Pat. No. 7,226,237 issued Jun. 5, 2007 to Ceccarelli
“Road barrier”, Current U.S. Class: 404/6; 256/13.1
The present invention deploys individual bollard(s), post(s) or stanchion(s) between an impacting vehicle and the physical manifestations of the above-mentioned current U.S. classification 256/13.1 and/or 404/6 devices or similar utility devices, to deplete or sap the incoming vehicle of some of its kinetic-energy before said vehicle engages the 256/13.1 and/or 404/6 devices or similar utility devices. The present invention converts (to the novelty of gating, kinetic-energy-depleting, cancellation-of-positive-vertical-vector-acquisition, and potential arming and/or engagement/deployment of incoming vehicle's on-board crash-safety-devices before said incoming vehicle makes physical contact with abovementioned 256/13.1 and/or 404/6 devices or similar utility devices) existing or similar devices as expressed in the present art such as but not limited to:
U.S. Pat. No. 1,284,376 issued Nov. 12, 1918 to Lehman
U.S. Pat. No. 4,438,484 issued Mar. 20, 1984 to Winden
“Lighting bollard for use in an urban environment”, Current U.S. Class: 362/267; 362/145; 362/153; 362/307; 362/308; 362/311; 362/363; 362/367; 362/368; 362/374; 362/375; 362/376; 362/390; 362/431
U.S. Pat. No. 4,576,508 issued Mar. 18, 1986 to Dickinson
“Bollard trafficway barrier and vehicle arrest system”, Current U.S. Class: 404/6; 256/DIG.5; 404/11; 404/9; 49/131; 49/49
U.S. Pat. No. 4,919,563 issued Apr. 24, 1990 to Stice
“Vehicle parking or passageway security barrier”, Current U.S. Class: 404/6; 49/49
U.S. Pat. No. 5,018,902 issued May 28, 1991 to Miller, et al.
“Collapsible bollards”, Current U.S. Class: 404/6; 49/131; 49/35; 49/49
U.S. Pat. No. 5,105,347 issued Apr. 14, 1992 to Ruud, et al.
“Bollard luminaire”, Current U.S. Class: 362/268; 362/153.1; 362/300; 362/346
U.S. Pat. No. 5,192,159 issued Mar. 9, 1993 to Higginson
“Security post”, Current U.S. Class: 404/11; 403/109.7; 49/131; 49/49
U.S. Pat. No. 5,365,694 issued Nov. 22, 1994 to Macaluso
“Vehicle anti-theft parking space device”, Current U.S. Class: 49/49; 49/131
U.S. Pat. No. 6,056,471 issued May 2, 2000 to Dinitz
“Multiple necked-down break-away coupling for highway or roadside appurtenances”, Current U.S. Class: 403/2; 411/5; 52/98
U.S. Pat. No. 6,099,200 issued Aug. 8, 2000 to Pepe, et al.
“Anti-terror bollard”, Current U.S. Class: 404/6; 256/13.1; 404/9
U.S. Pat. No. 6,390,436 issued May 21, 2002 to Barnes, et al.
“Breakaway sign post”, Current U.S. Class: 248/548; 248/909; 403/2; 52/98
U.S. Pat. No. 6,408,590 issued Jun. 25, 2002 to Cote
“Breakaway utility pole”, Current U.S. Class: 52/726.4; 248/545; 248/548; 248/900; 52/732.3; 52/98
U.S. Pat. No. 6,409,156 issued Jun. 25, 2002 to Dent
“Breakaway bracket”, Current U.S. Class: 256/13.1; 248/548; 403/2; 52/98
U.S. Pat. No. 6,422,783 issued Jul. 23, 2002 to Jordan
“Breakaway post slipbase”, Current U.S. Class: 404/9; 256/13.1; 40/607.05; 40/607.1; 403/2; 52/98
U.S. Pat. No. 6,457,895 issued Oct. 1, 2002 to Salman
“Flush mount breakaway post coupler”, Current U.S. Class: 403/2; 256/1; 403/374.1; 403/374.3; 52/169.3; 52/98
U.S. Pat. No. 6,516,573 issued Feb. 11, 2003 is Farrell, et al.
“Integrated breakaway for support posts”, Current U.S. Class: 52/98; 116/63R; 248/548; 40/612; 403/2; 404/10; 404/6; 404/9; 52/720.1
U.S. Pat. No. 6,540,196 issued Apr. 1, 2003 to Ellsworth
“Break away support structure coupling”, Current U.S. Class: 248/548; 248/900; 256/13.1; 403/2; 52/98
U.S. Pat. No. 6,805,515 issued Oct. 19, 2004 to Reale
“Assembly with a removable bollard”, Current U.S. Class: 404/11; 49/49
U.S. Pat. No. 6,848,856 issued Feb. 1, 2005 to Johnson
“Rectractable pylori arrangement”, Current U.S. Class: 404/6; 404/10; 49/131; 49/49
U.S. Pat. No. 6,910,826 issued Jun. 28, 2005 to Damiano
“Breakaway coupling”, Current U.S. Class: 403/2; 403/21; 411/2; 411/427; 411/429
U.S. Pat. No. 6,945,730 issued Sep. 20, 2005 to Lobban
U.S. Pat. No. 6,959,902 issued Nov. 1, 2005 to Leahy
“Breakaway signpost connector”, Current U.S. Class: 248/548; 248/530; 403/2; 52/296; 52/98
U.S. Pat. No. 7,052,201 issued May 30, 2006 to Zivkovic
“Safety bollard”, Current U.S. Class: 404/11; 404/10; 404/9
U.S. Pat. No. 7,056,056 issued Jun. 6, 2006 to Wiegand, et al.
“Collision safety device having a breakaway shear coupling”, Current U.S. Class: 404/10; 248/548; 248/909; 403/2
Particular attention is directed to present art devices as expressed in:
U.S. Pat. No. 433,001 issued Jul. 29, 1890 to Hall
U.S. Pat. No. 3,349,531 issued Oct. 31, 1967 to Watson
“Frangible connector assembly for stanchions, poles and standards”, Current U.S. Class: 52/296; 403/11; 403/2; 403/298; 403/376; 404/6; 404/9; 52/40; 52/98
U.S. Pat. No. 4,355,754 issued Oct. 26, 1982 to Lund, et al.
“Structural members comprised of composite wood material and having zones of diverse density”, Current U.S. Class: 238/83; 156/283; 156/284; 156/296; 156/62.2; 256/13.1; 428/113; 428/170; 428/171; 428/194; 428/218; 428/326; 428/425.1; 428/528; 428/529; 428/537.1; 428/63; 52/729.1; 52/737.3
U.S. Pat. No. 4,437,427 issued Mar. 20, 1984 to Mampaeij
“Break bollard”, Current U.S. Class: 114/218; 24/115F; 403/2; 411/5
One important teaching of Mampaeij is: (col. 1, line 16) “It is conventional for such bollards—called “break bollards”, and whose aim it is, in case a given force exerted thereon by the vessel is exceeded, that the bollard attachment can collapse in order to thus prevent calamities—to provide anchoring bolts through which the base plate is secured to the stationary support construction, with a weakened region of incipient fracture. Said region should then lie underneath the nut through which the base plate is pressed down on said support construction by tightening said nut. In case of collapse of the weakened region of incipient fracture of the anchoring bolts, elaborate operations are necessary in this known embodiment for again anchoring the bollard in its original state. The anchoring bolts have to be replaced so that substantial breaking operations in the stationary support construction are required.”
U.S. Pat. No. 4,939,037 issued Jul. 3, 1990 to Freeman, et al.
“Composite sign post”, Current U.S. Class: 428/36.3; 138/130; 40/607.05; 40/607.12; 404/10; 405/298; 428/34.4; 428/34.5; 52/298; 52/98
Freeman teaches that it is (col. 4, line 32) “Important to the choice of the overall cross-sectional dimensions is the consideration of the design loads that the improved post I will be subject to. The calculation of these loads is a simple matter of structural design. Obvious considerations are the loads generated by installation, by weight of the sign 2 or signs attached, and for the larger signs, wind pressure and wind buffeting loads. Once the design loads have been calculated the required bending stiffness and torsional stiffness are known. With these known values, design of the post is a matter of providing a suitable cross section for a given modulus of elasticity, or conversely by providing a suitable modulus of elasticity for a given cross section. The key to designing a post that has a built in controlled failure mode, is to design a composite with the desired modulus of elasticity, provided by correctly orienting the fibers.”
U.S. Pat. No. 5,480,121 issued Jan. 2, 1996 to Rice, et al.
“Break-away connector for sign post”, 248/548; 248/900; 403/2; 404/10; 52/98
U.S. Pat. No. 5,484,217 issued Jan. 16, 1996 to Carroll, et al.
“Restorable breakaway post”, Current U.S. Class: 403/2; 248/548; 404/10; 52/98
Carroll teaches of (col. 2, line 44) “A flexible member, such as a cable, band, strap or the like, has one end secured with respect to the base post and an opposite end secured with respect to the breakaway post. It is apparent that such flexible member can be secured in any suitable manner known to those skilled in the art . . . . When an impact force is applied to the breakaway post, the splice plate fractures and thus allows the breakaway post to separate from its mounted position with respect to the base post and to move away from the base post, such as toward the ground. The flexible member is used to retain the breakaway post in the general location of the base post as the breakaway post moves away from the base post. To restore the breakaway post to its initial position, the damaged splice plate is removed and a new splice plate is simply fastened into the initial position. It is apparent that with removable fasteners the breakaway post can be quickly and economically restored to its initial position after experiencing a destructive impact force.”
The present invention utilizes these teachings and amalgamates them into novel, low cost, devices which enhance highway safety in non-apparent ways of the following issued U.S. patents:
U.S. Pat. No. 3,881,697 issued May 6, 1975 to Glaesener ('697)
Glaesener teaches that (col. 1, line 12) “Various systems have been proposed for preventing injury to vehicular travelers and to protect objects along the roadside from impact with a vehicle. These systems can be termed general or local depending upon their ultimate function and character. General safety systems are those which may extend for relatively long distances along the shoulder of a road or along the median strip of two-directional highways and operate by retaining the vehicle in its travel lane and preventing it from leaving the road or crossing the median into an oncoming traffic lane.”
(col. 1, line 23) “Such systems may require a multiplicity of spaced-apart upright posts and guard rails spanning the posts and of a strength sufficient to absorb by deformation the impact energy of a vehicle and to prevent the vehicle from going through the guard rail or caroming thereover. The rail should not be excessively rigid, in order to limit damage to the vehicle; and it must not be of such design as simply to deflect the vehicle onto parallel traffic without reduction of speed or energy absorption.”
(col. 1, line 33) “The second type of barrier is designed for local protection and may be disposed at abutments along a traffic lane, e.g. at the start of a median strip, at the junction between a turnoff and a main traffic lane, at lightposts, stanchions, sign-posts or other uprights disposed on the road shoulder, directly upon roadways between traffic lanes, at walls and pillars of overpasses, and the like. These barriers must be of the energy-absorbing type and may consist of bodies filled with sand or a liquid and designed to receive an impact with the vehicle such that the vehicle speed is progressively reduced and all of the impact energy is not instantaneously dissipated. The deceleration of the passengers is thus held to a reasonable level and the danger of serious damage to the vehicle is minimized.”
(col. 1, line 63) “There have been proposed various arrangements of this latter type in which the energy-absorbing drum is spaced above the ground on one or more posts which themselves may be rigid and frequently can intercept the vehicle with excessively sudden deceleration. In other cases the drum may be torn away or may be ineffective on leverage grounds in the energy-absorbing interception of a motor vehicle.”
Glaesener's '697's independent claim reads:
(col. 5, line 20) “1. A road barrier for protection of a vehicle and its occupants in an impact with a stationary object, said barrier comprising a support base widening in the direction of said object, and a correspondingly widening array of a multiplicity of upright elongated impact-absorbing bendable elements having lower ends mounted on said support base and each consisting of an upright bar having a lower end sunk into said support and extending below the grounds, said bars having free upper ends and being of generally continuous cross section throughout their length and being arrayed so as to provide a greater cross-sectional density per unit of surface area close to said object than remote therefrom, said bars being spaced apart and staggered along said support base, the number of bars per unit ground area being greater close to said object than remote therefrom.”
Glaesener's '697 Summary of the '697 invention reads:
(col. 2, line 29) “These objects are attained according to the present invention in a barrier arrangement wherein a plurality of impact-absorbing upright elements are sunk into the ground and are arranged in an array of increasing cross-sectional density in the direction of the stationary objects. Thus the elements increase in number and/or cross-sectional size so that the resistance thus offered to bending and deflection increases toward the object. A vehicle is therefore braked with increasing force as the object is approached.”
Impracticalities were encountered during numerous full-scale crash testing I conducted on devices similar to that taught by Glaesener '697 and in the process of reducing my U.S. Pat. No. 6,454,488 to practice. Application of '697 to the present day highway safety standards, such as the American NCHRP 350 and the European EN 1317 identified four (4) issues not discussed by '697, because Glaesener predates such design requirements.
The first issue I've identified is, regardless of the construction and/or materials used for '697 “upright elements”, once laterally loaded by an impacting vehicle, said loaded upright-element deflects away from the applied load. Such deflection results in an interaction between said impacting vehicle and said upright element(s) whereby a generally positive (upward) vertical vector is imparted to the initial impacting section (usually the front end) of said impacting vehicle. (see FIGS. 21-27 in reference to FIG. 20) Such positive vertical vector transference to the impacting vehicle (in the case of most of my full-scale crash tests, NCHRP 350 rated pickup trucks) has resulted in said vehicles leaving the ground in a large, flat, arced flight similar to the Wright Brothers initial, successful flights. Still photos of some of these vehicle liftoffs, obviously unintended by '697) are presented herein.
Glaesener '697 teaches (col. 2, line 31) that a '697 device provides for a “ . . . vehicle . . . ” to be “ . . . braked with increasing force as the object is approached.” This is contrary to the kinetic-energy formula:
Glaesener '697 does not recognize that an impacting vehicle must be “braked” with decreasing force, not increasing force, as the vehicle's total kinetic-energy is reduced by the change in velocity (delta-V, Δ-V) with each encounter of a '697 post, if the impacting vehicle's occupant(s) are not to be exposed to ever greater deceleration.
The present invention recognizes that each succeeding '697 post must cause a lesser Δ-V thru transfer of kinetic-energy from the impacting vehicle to the '697 post, if the vehicle's occupant(s) are to experience only minor change in their deceleration rates.
The second issue I've identified thru full-scale testing of my U.S. Pat. Nos. 6,367,208; 6,454,488 and 6,561,492 devices is that the friction developed between said impacting vehicle and said upright-element has a significant influence on the size and origination of the resultant, generally positive, vector transferred to said impacting vehicle. The present art teaches the importance of friction reduction in the safety deceleration of impacting vehicles. Examples of such present art are
U.S. Pat. No. 3,519,249 issued Jul. 7, 1970 to Nave
(col. 1, line 28) “ . . . upon impact by a vehicle, . . . lubricating the surfaces of contact and enabling the vehicle to guide to a halt rather than causing it to stop abruptly.”
U.S. Pat. No. 2,279,942 issued Apr. 14, 1942 to Hausherr
(col. 2, line 21) “As is well known, when an automobile skids it is generally at an angle, and as the instant device presents the shaped front which would cause an automobile to “ride” the front plate, while the wheels could not revolve, which with the entire surface of the shaped front plate being supplied at all times with a supply of oil, there would be no traction, and the vehicle would slide back to the ground and under control of the operator.”
U.S. Pat. No. 4,662,611 issued May 5, 1987 to Ruane
(col. 1, line 7) “ . . . produces a reduced resistance to advancement of a vehicle in a selected direction.”
U.S. Pat. No. 4,982,931 issued Jan. 8, 1991 to Pomero
“Process and devices for retaining vehicles on a highway”, Current U.S. Class: 256/13.1; 256/19; 404/7
(col. 2, line 33) “ . . . provide means for facilitating slide of the crashed vehicles against the safety rails . . . placed along the highways and motorways, which means are easier and less expensive to employ than lubricating liquids and are permanent.”
The present invention applies the above teaches in a non-apparent way by applying such “friction” issues in the vertical dimension, or post face, instead of the present art's application in the horizontal plane.
The third issue I've identified is the need to minimize or eliminate interaction between said impacting vehicle and said impacted upright-element(s) and other upright-element(s) not yet directly engaged by said impacting vehicle. In one of my fill-scale pickup truck crash tests, involving the testing of upright-elements, exhibiting significant load vs deflective characteristics, the initially impacted upright element(s) bent away from the impact load and encountered and made contact with upright-element(s) not previously impacted by said vehicle. The deflected upright-element(s) formed a structural system with the yet to be engaged upright-element(s) and provided de facto ramp which exacerbated the pickup truck's vertical vector.
The fourth issue I've identified is the need to minimize or eliminate interaction between and/or among upright-element pieces which may intentionally or unintentionally become structurally separated due to the vehicle's impact. This phenomenon was exhibited during my full-scale crashing in reducing to practice my U.S. Pat. Nos. 6,367,208; 6,454,488; 6,561,492 and U.S. Pat. No. 5,402,987 for which I hold a North American License.
Glaesener improved on '697 and was issued U.S. Pat. No. 4,047,701 issued Sep. 13, 1977 to Glaesener ('701). Glaesener '701 teaches:
(col. 1, line 16) “In a roadside barrier having a guard rail held above and parallel to the ground by a plurality of breakaway posts, the end of the guard rail turned toward the oncoming traffic passing the rail creates a considerable hazard. When a vehicle collides with the rail at any location other than the end of the rail the posts snap off and the considerable kinetic energy of the vehicle is absorbed by the entire rail so as to slow down and gently stop the vehicle without ricoheting it back into the traffic.”
(col. 1, line 26) “When the end of the guard rail is merely allowed to project beyond the end post it is usually necessary to provide some protective arrangement such as shock-absorbing blocks or the like. This projecting end otherwise constitutes a considerable hazard for a motor vehicle striking it.”
(col. Line 33) “It has also been suggested to bend the guard rail down at its end and bury it in the ground. Although this prevents the rail from impaling a vehicle colliding with it, it has the extremely dangerous effect of prying the vehicle up and often flipping it over in its own traffic lane or in the opposite traffic lane. The vehicle merely rides up the bent-down end section until it is overturned or simply launched over the guard rail.”
(col. 1, line 56) “These objects are attained according to the present invention in an end assembly for a guard rail which comprises a generally straight beam which is at least 25 m long and has one end secured to the end of the guard rail and the other end seated in or on the ground with the beam inclined to the ground downwardly from the rail to its other end. At least one support or post is provided between the ends of the beam with its upper end or side secured to the beam and its lower end or side seated on the ground and this post is provided with means between its upper and lower ends allowing it to shorten vertically when compressed vertically with a force exceeding a predetermined level. Thus at least a portion of the kinetic energy of a vehicle colliding with the beam is absorbed by the post as it collapses.”
(col. 2, line 3) “According to another feature of this invention the beam is of the metallic shell type having an outer profiled metal shell which may be filled with synthetic-resin foam. Such a structure is extremely rigid and, when made of sheet steel having a thickness of up to 6 mm, may be used without a synthetic-resin filling; when sheet steel of between 1 mm and 3 mm thickness is used, a hard polyurethane foam filling imparts to it sufficient strength to allow the beam to withstand even severe collisions without breaking. In both cases the beam remains relatively yieldable so that it deforms and absorbs the kinetic energy of a vehicle colliding with it. Regardless of the construction of the beam the posts are made of the breakaway type so that the kinetic energy of a colliding vehicle is transmitted through the entire structure.”
Glaesener '701 eludes to impacting vehicles being “launched” (col. 1, line 39) but does not provide workable solutions.
Glaesener improved on '697 & '701 and was issued U.S. Pat. No. 4,290,585 issued Sep. 22, 1981 ('585)
(col. 2, line 52) “It is the principal object of the present invention, to provide an improved upright construction for use in a safety barrier of the type described in U.S. Pat. No. 3,881,697, but which is free from the disadvantages thereof, namely, high replacement cost.”
(col. 2, line 57) “Another object of the invention is to provide an improved upright or post for use in safety barriers which has improved energy absorption but which, subsequent to impact, can be restored readily and relatively inexpensively to an effective state.”
(col. 2, line 62) “Yet another object of the invention is to provide an improved safety barrier which is amenable to restoration to an operative state after impact in an expensive and efficient manner and which, nevertheless, affords the gradual stopping of a misdirected motor vehicle with the qualities of the system described in U.S. Pat. No. 3,881,697.”
To date, none of the Glaesener-type devices nor these mentioned above address the interplay between highway safety devices that are intended to be highway “crash-cushions” and/or “end-terminals” as defined by NCHRP 350 and vehicle on-board safety devices which are intended to react to impacts. This fifth issue addressed by the present invention is the effect of deployment of the above-referenced vehicle on-board safety devices before the impacting vehicle engages the above-referenced highway safety devices. While there may be present art addressing such concerns, there is no evidence of such being reduced to practice. Specifically, any such NCHRP 350 device would require formal acceptance by the U.S. Federal Highway Administration (FHWA) if used on the U.S. National Highway System (NHS) and similar governmental requirements elsewhere such as but not limited to the European highway safety regulations EN 1317. A review of FHWA NCHRP 350 device Acceptance Letters, available on the FHWA website, show no such device, addressing the abovementioned intended interplay of roadside and on-board safety devices, approved for use. A similar, but more limited, review of European approved devices also show no such interplay. The following listing is of highway “crash-cushions” and/or “end-terminals” as defined by NCHRP 350, and accepted/approved by FHWA as per the FHWA website as of Jun. 30, 2006. There are a total of about 200 individual devices and alternate device configurations listed. Examples of the devices of interest herein are:
|Acceptance Letter CC-12C||(1995)||for device ET-2000|
|Acceptance Letter CC-12D||(1996)||for device ET-2000|
|Acceptance Letter CC-12E||(1998)||for device ET-2000|
|Acceptance Letter CC-12F||(1999)||for device ET-2000|
|Acceptance Letter CC-12G||(2000)||for device ET-2000|
|Acceptance Letter CC-12H||(2000)||for device ET-2000|
|Acceptance Letter CC-12I||(2000)||for device ET-2000|
|Acceptance Letter CC-12J||(2002)||for device ET-2000|
|Acceptance Letter CC-12K||(2002)||for device ET-2000|
|Acceptance Letter CC-12L||(2003)||for device ET-2000|
|Acceptance Letter CC-12M||(2004)||for device ET-2000|
|Acceptance Letter CC-12N||(2005)||for device ET-2000|
|Acceptance Letter CC-12P||(2005)||for device ET-2000|
|Acceptance Letter CC-25||(1995)||for device NEAT|
|Acceptance Letter CC-26||(1995)||for device REACT 350|
|Acceptance Letter CC-26A||(1995)||for device REACT 350|
|Acceptance Letter CC-26B||(1995)||for device REACT 350|
|Acceptance Letter CC-26C||(1995)||for device REACT 350|
|Acceptance Letter CC-26D||(1996)||for device REACT 350|
|Acceptance Letter CC-26E||(1997)||for device REACT 350|
|Acceptance Letter CC-26F||(1997)||for device REACT 350|
|Acceptance Letter CC-26G||(1998)||for device REACT 350|
|Acceptance Letter CC-26H||(2005)||for device REACT 350|
|Acceptance Letter CC-26I||(2006)||for device REACT 350|
|Acceptance Letter CC-27||(1995)||for device VAS|
|Acceptance Letter CC-27A||(2005)||for device VAS|
|Acceptance Letter CC-28||(1995)||for device FITCH UNIVERSAL|
|Acceptance Letter CC-29||(1995)||for device ENERGITE III|
|Acceptance Letter CC-31||(1995)||for device SRT|
|Acceptance Letter CC-31||(1998)||for device SRT|
|Acceptance Letter CC-33||(1996)||for device CAT|
|Acceptance Letter CC-33A||(2002)||for device CAT|
|Acceptance Letter CC-35||(1996)||for device QUADGUARD|
|Acceptance Letter CC-35A||(1996)||for device QUADGUARD|
|Acceptance Letter CC-35B||(1996)||for device QUADGUARD|
|Acceptance Letter CC-35C||(1999)||for device QUADGUARD|
|Acceptance Letter CC-35D||(2001)||for device QUADGUARD|
|Acceptance Letter CC-35E||(2001)||for device QUADGUARD|
|Acceptance Letter CC-35F||(2003)||for device QUADGUARD|
|Acceptance Letter CC-37||(1996)||for device BEST-350|
|Acceptance Letter CC-37A||(1997)||for device BEST-350|
|Acceptance Letter CC-37B||(1997)||for device BEST-350|
|Acceptance Letter CC-37C||(1997)||for device BEST-350|
|Acceptance Letter CC-38||(1997)||for device ADIEM|
|Acceptance Letter CC-40||(1997)||for device SKT-350|
|Acceptance Letter CC-40A||(2000)||for device SKT-350|
|Acceptance Letter CC-40B||(2004)||for device SKT-350|
|Acceptance Letter CC-41||(1997)||for device BRAKEMASTER|
|Acceptance Letter CC-42||(1997)||for device QUARDGUARD-WIDE|
|Acceptance Letter CC-42A||(2003)||for device QUARDGUARD-WIDE|
|Acceptance Letter CC-43||(1997)||for device QUARDGUARD-LOW|
|Acceptance Letter CC-44||(1998)||for device LOW-PROFILE|
|Acceptance Letter CC-45||(1998)||for device QUARDGUARD-69/90|
|Acceptance Letter CC-46||(1998)||for device FLEAT-350|
|Acceptance Letter CC-46A||(1998)||for device FLEAT-350|
|Acceptance Letter CC-46B||(1999)||for device FLEAT-350|
|Acceptance Letter CC-46C||(2001)||for device FLEAT-350|
|Acceptance Letter CC-46D||(2001)||for device FLEAT-350|
|Acceptance Letter CC-47||(1998)||for device TRITON|
|Acceptance Letter CC-47A||(2003)||for device TRITON|
|Acceptance Letter CC-47B||(2004)||for device TRITON|
|Acceptance Letter CC-48||(1998)||for device REGENT|
|Acceptance Letter CC-49||(1998)||for device QUADTREND|
|Acceptance Letter CC-50||(1998)||for device WIDE-REACT|
|Acceptance Letter CC-50A||(1999)||for device WIDE-REACT|
|Acceptance Letter CC-50B||(1999)||for device WIDE-REACT|
|Acceptance Letter CC-51||(1998)||for device ISRT|
|Acceptance Letter CC-51A||(1999)||for device ISRT|
|Acceptance Letter CC-52||(1998)||for device TRAFIX SAND|
|Acceptance Letter CC-52A||(1999)||for device TRAFIX SAND|
|Acceptance Letter CC-52B||(2002)||for device TRAFIX SAND|
|Acceptance Letter CC-53||(1998)||for device FHWA BACKSLOPE|
|Acceptance Letter CC-53A||(2001)||for device FHWA BACKSLOPE|
|Acceptance Letter CC-54||(1998)||for device TRACC|
|Acceptance Letter CC-54A||(2000)||for device TRACC|
|Acceptance Letter CC-54B||(2001)||for device TRACC|
|Acceptance Letter CC-54C||(2002)||for device TRACC|
|Acceptance Letter CC-54D||(2002)||for device TRACC|
|Acceptance Letter CC-54E||(2003)||for device TRACC|
|Acceptance Letter CC-54F||(2004)||for device TRACC|
|Acceptance Letter CC-54G||(2005)||for device TRACC|
|Acceptance Letter CC-54H||(2005)||for device TRACC|
|Acceptance Letter CC-56||(1998)||for device ELT|
|Acceptance Letter CC-56A||(1999)||for device ELT|
|Acceptance Letter CC-57||(1998)||for device QUADGUARD-ELITE|
|Acceptance Letter CC-57A||(1999)||for device QUADGUARD-ELITE|
|Acceptance Letter CC-58||(1999)||for device NCIAS|
|Acceptance Letter CC-60||(1999)||for device WYBET-350|
|Acceptance Letter CC-60A||(1999)||for device WYBET-350|
|Acceptance Letter CC-61||(1999)||for device SKT-350 & FLEAT|
|Acceptance Letter CC-61A||(2002)||for device SKT-350|
|Acceptance Letter CC-61B||(2004)||for device SKT-350 & FLEAT|
|Acceptance Letter CC-61C||(2004)||for device SKT-350 & FLEAT|
|Acceptance Letter CC-62||(1999)||for device G1-d|
|Acceptance Letter CC-63||(2000)||for device NY 3-STRAND|
|Acceptance Letter CC-66||(2000)||for device ABSORB-350|
|Acceptance Letter CC-66A||(2000)||for device ABSORB-350|
|Acceptance Letter CC-66B||(2003)||for device ABSORB-350|
|Acceptance Letter CC-68||(2000)||for device Bullnose|
|Acceptance Letter CC-69||(2000)||for device BEAT|
|Acceptance Letter CC-69A||(2002)||for device BEAT|
|Acceptance Letter CC-69B||(2002)||for device BEAT|
|Acceptance Letter CC-69C||(2003)||for device BEAT|
|Acceptance Letter CC-69D||(2004)||for device BEAT|
|Acceptance Letter CC-70||(2000)||for device WorkZoNet|
|Acceptance Letter CC-71||(2000)||for device EASI-Cell|
|Acceptance Letter CC-72||(2000)||for device SRT|
|Acceptance Letter CC-73||(2001)||for device REACT-350|
|Acceptance Letter CC-73A||(2002)||for device REACT-350|
|Acceptance Letter CC-73B||(2005)||for device REACT-350|
|Acceptance Letter||(2006)||for device REACT-350|
|Acceptance Letter CC-75||(2001)||for device TAU-II|
|Acceptance Letter CC-75A||(2002)||for device TAU-II|
|Acceptance Letter CC-75B||(2003)||for device TAU-II|
|Acceptance Letter CC-75C||(2004)||for device TAU-II|
|Acceptance Letter CC-76||(2002)||for device 3-STRAND CABLE|
|Acceptance Letter CC-80||(2002)||for device REGENT|
|Acceptance Letter CC-81||(2002)||for device ET-2000|
|Acceptance Letter CC-82||(2003)||for device FASTBRAKE|
|Acceptance Letter CC-84||(2003)||for device MELT|
|Acceptance Letter CC-85||(2003)||for device 100GM|
|Acceptance Letter CC-85A||(2005)||for device 100GM|
|Acceptance Letter CC-85B||(2005)||for device 100GM|
|Acceptance Letter CC-86||(2004)||for device BRIFEN TERMINAL|
|Acceptance Letter CC-86A||(2005)||for device BRIFEN TERMINAL|
|Acceptance Letter CC-87||(2005)||for device QUEST|
|Acceptance Letter CC-87||(2005)||for device QUEST|
|Acceptance Letter CC-87A||(2006)||for device QUEST|
|Acceptance Letter CC-88||(2005)||for device SKT & FLEAT|
|Acceptance Letter CC-89||(2005)||for device HEART|
|Acceptance Letter CC-91||(2005)||for device ARMORFLEX X350|
|Acceptance Letter CC-92||(2005)||for device GIBRALTAR CABLE|
|Acceptance Letter CC-93||(2005)||for device SAFENCE CABLE|
|Acceptance Letter CC-94||(2005)||for device ET-2000|
Of the above, some of the more commercially viable, as highway safety devices, meeting the standards of NCHRP 350 have been: ET-2000, REACT 350, QUADGUARD, BEST-350, SKT-350, FLEAT-350, TRACC, BEAT, and TAU-II. While the present invention may be used in conjunction with the aforementioned safety devices, for illumination purposes and for reasons to be put forth hereafter, the above listed highway safety devices known as the ELT and the MELT, which are open art devices, will be used in the following narrative.
NCHRP 350 separates highway safety devices into various categories such as “crash-cushions”, “longitudinal-barriers”, and “bridge-railings”. The present invention combines, in novel ways, two (2) other NCHRP 350 categories, “end-terminals” and “breakaway-sign-supports”. Under NCHRP 350, the maximum allowable deceleration for “breakaway-sign-supports” is 5 m/s and the maximum allowable deceleration for “end-terminals” is 12 m/s. Use of “breakaway-sign-supports” type configurations designed to decelerate at or below 12 m/s, in conjunction with the abovementioned “end-terminals”, and defining the two separate safety devices as a single safety system, allows the above listed devices to be upgraded to higher impact kinetic-energy impacts as the present invention independently absorbs impacting vehicle energy before said vehicle engages said above listed devices. By triggering the impacting vehicle's on-board safety equipment, by inducing significant deceleration in the impacting vehicle, said on-board safety equipment will deploy before the vehicle engages the extreme decelerations associated with impacts on the above listed devices when such impacts are at or above the kinetic-energy levels proscribed by NCHRP 350. This is important in part because NCHRP 350 only requires highway safety devices such as these listed above to withstand 62 mph (100 km/hr) vehicle impacts, such vehicle speeds being significantly below that found on today's NHS. That said, use of the ELT and MELT in conjunction with the present invention, provides the overall performance required by NCHRP 350 for Test Level 3 (TL-3) devices.
Desirable characteristics of the present invention's novel, low cost, enhancement of highway safety, by allowing an independent means of upgrading existing present art end terminals and crash cushions include:
U.S. Pat. No. 4,047,701 issued Sep. 13, 1977 to Glaesener ('701) teaches that: (col. 1, line 18) “When . . . posts snap off . . . considerable kinetic energy of the vehicle is absorbed . . . ”
NCHRP 350 Test Level 3 requires Glaesener '701-type devices to specifically address a number of vehicle crash test event configurations. Said specific crash tests, in general terms, require impact decelerations of a small car and a mid-size pickup truck to not exceed 12 m/s. given an initial velocity of 100 km/hr. (Chapter 5, Table 5.1. (report page 54), Item H. “Occupant impact velocities . . . should satisfy the following:” “Occupant Impact Velocity Limits (m/s)” Preferred 9 Maximum 12.)
The small car test places a maximum upper limit on how much “ . . . kinetic energy of the vehicle is absorbed . . . ” per impact encounter.
The larger mass and higher center-of-mass pickup truck vehicle places a minimum number of kinetic-energy impact encounters needed to reduce the pickup truck's velocity in which no single impact exceeds the maximum small car allowable.
The present invention may be considered a Gating Impact Attenuator Decelerator (GIAD), as defined by the National Cooperative Highway Research Program (NCHRP) Report 350 (350), for use as a stand-alone highway safety device or in conjunction with other highway safety devices.
For illustrative purposes the following discussion highlights specific applications of GIAD in concert with specific existing highway safety devices and the overall upgrading of highway safety thru the deployment of GIAD devices. The Federal Highway Administration (FHWA) has approved for use on the National Highway System (NHS) three (3) highway guardrail end-terminals known as the Eccentric Loader Terminal (ELT), the Modified Eccentric Loader Terminal (MELT) and the G-1d W-beam Guardrail Terminal (G-1d). With the exception of a specific site limitation (Minnesota DOT) the MELT, the ELT and the G-1d are FHWA approved NCHRP 350 Test Level 2 (TL-2) devices. TL-2 devices are approved for use on 45 mph or lower speed highways. The present invention provides an inexpensive, novel means and methods to upgrade these TL-2 devices, with the addition of a GIAD device, to an overall Test Level 3 (TL-3) condition. In the case of new installations of MELT, ELT and G-1d type devices, the addition of a GIAD will add little to the overall costs. In the case of upgrading existing MELT, ELT and G-1d type devices, the placement of a GIAD device, before these existing devices, provide significant, inexpensive, improvements in highway safety.
Each of these existing TL-2 devices has a complex history of failed testing to achieve a TL-3 rating. For example, quoting from FHWA's Dwight A. Home, Chief, Federal-Aid and Design Division Letter of Dec. 24, 1998 to Mr. Darryl E. Durgin, Deputy Commissioner, Chief Engineer, Minnesota Department of Transportation: “We agreed . . . that the angle hits on the nose of the ELT (tests 3-32 and 3-33) and the reverse direction test (3-39) could be waived . . . ” and “(w) e . . . agreed that earlier tests run . . . (test 3-30) and . . . (test 3-34) need not be repeated . . . ” Further, “(t)he researchers reviewed and we concur in their findings that both of these small car tests essentially conformed to the current NCHRP Report 350 test and that neither test need be repeated.” Finally, “(t)he NCHRP Report 350 recommends up to seven tests . . . ”
Based on the above paragraph, the small car (820 kg test vehicle) crash test requirements for an NCHRP 350, TL-3 end terminal device are, in toto, 3-30, 3-32, and 3-34. Based on the Durgin Letter and FHWA Memorandum, dated Sep. 4, 1997, for both the MELT and the ELT, it appears that the small car requirements have repeatedly been met.
To summarize the above, NCHRP 350, the Durgin Letter and FHWA Memorandum, dated Sep. 4, 1997, the pickup truck (2000 kg test vehicle) crash test requirements are 3-31, 3-33, 3-35, 3-39 and for both the ELT and MELT it appears that the pickup truck tests 3-33 and 3-39 have been repeatedly met. The above suggests that unqualified certification of the ELT and MELT, in their present configurations, lack only a not apparent, novel, inexpensive solution to pickup truck crash tests 3-31 and 3-35. From the Durgin Letter it appears that test 3-35, while accepted as meeting test level 3, is qualified as requiring the use of only “ . . . straight sections of W-beam.” As such, the ELT and MELT devices lack only an acceptable test 3-31 to have a qualification-free approval as a Test Level 3 device. (noting that while “ . . . the W-beam was near its breaking point, . . . ”, the recent work by Dr. Mac Ray appears to address the issue of W-beam rupture, the 3-35 test can be assured by moving the W-beam splice to midway between posts and requiring the W-beam steel to not be of a “high-strength-brittle” nature.
The above refines the issue of unqualified TL-3 certification of ELT and MELT to addressing Test 3-31. Quoting from NCHRP 350, 184.108.40.206 Description of Tests, “Tests 31 . . . conducted with the vehicle approaching parallel to the roadway with impact at the vehicle's centerline. For a device designed to decelerate a vehicle to a stop, these tests are intended to evaluate the capacity of the device to absorb the kinetic energy of the 2000P vehicle (structural adequacy criteria) in a safe manner (occupant risk criteria).” This highlights two aspects of previously conducted 3-31 crash tests. The two aspects are:
1) the apparently inconsistent test results contained in FHWA Memorandum, dated Sep. 4, 1997 wherein TTI 471470-34 was a fail and TTI 471470-35 was a pass. From the Durgin Letter, the very qualified “pass” where “ . . . the pickup truck rode on the rail for approximately 45 m in the end-on test.”, and
2) the recent, successful TL-2 MELT tests conducted by TTI. Quoting from Memorandum AASHTO/AGC/ARTBA Joint Committee Task Force 13 Meeting Minutes, Spring 2002—April 11 & 12, provided via E-mail by FHWA, page 7, entitled Technical Presentation, 6. Dean Alberson—TTI Crash Tests, “(t)he following tests were shown and discussed: . . . New England Transportation Consortium test of MELT to TL-2”. My son, Alistair Hubbell, who attended the above mentioned Spring 2002 Task Force 13 Meeting, reports that Dr. Alberson stated that MELT in fact met the NCHRP 350 crash test results for a Test Level 2 certification. I called Dr. Alberson, on May 8, 2002, in the morning, and he verbally confirmed that TTI had had a successful series of TL-2 MELT tests and that a request for acceptance had been submitted to FHWA. It is my understanding of my conversation with Dr. Alberson that the 3-31 test data shows the pickup truck with an impact speed of 71.6 km/hr. at an angle of 0.2°.
To summarize, the only reason why the MELT and ELT have not been granted unqualified NCHRP 350 TL-3 acceptance by FHWA is the inconsistent performance, of the present MELT and ELT configurations, above TL-2, 2-31 perimeters. That is, the MELT and ELT fall short of TL-3 solely because of their inability “ . . . to absorb the kinetic energy of the 2000P vehicle . . . in a safe manner.” Now, with “ . . . the New England Transportation Consortium test of MELT to TL-2”, it is known that the MELT and ELT are capable of handling the kinetic energy of the 2000P vehicle at the 2-31 energy level. As such, the only hurdle needed to be cleared to give the public the benefits of the MELT and ELT (safer, less expensive) for use as a TL-3 end terminal device is to provide a means and method to reduce the speed of the pickup truck, in the 3-31 test, from 100 km/hr. to 70 km/hr before the pickup truck encounters the noise of the MELT or ELT and to effect such a deceleration “ . . . in a safe manner.”
One embodiment of the present invention, to decelerate the impacting vehicle from 100 km/h to 70 km/h before it encounters the MELT or ELT, is the use of 31b. U-Channel Posts. Said 31b post has a well documented and long service history. It also exhibits some predictable deceleration characteristics for both the small car and the pickup truck test vehicles. For example, the public document “A Guide to Small Sign Support Hardware, June 1998, AASHTO-AGC-ARTBA Joint Committee, Subcommittee on New Highway Materials, Task Force 13 Report, Standardization of Details for Bridge and Road Hardware” states that a pair of 3 lb posts decelerates the small car test vehicle by 3.57 m/s. Beginning in early 1999, I ran a series of private crash tests on both pickup trucks and small cars. I successfully crash tested an 820 kg car into 3 lb posts at 50 km/hr (+/−) and brought the vehicle to a very controlled, stable, stop by shearing off an equivalent of 16 each 3 lb posts. While I was not able to determine the change in velocity as the test car impacted each 3 lb post, this 1999 test series validated the present invention's concept and identified the need to address and minimize or neutralize vertical vector acquisition by impacting vehicles on traditional breakaway sign support devices.
The methodology for use of an already FHWA approved small sign post as a decelerator component in conjunction with a MELT or ELT is to provide absorption of kinetic energy from the pickup truck crash vehicle such that said pickup truck's speed drops from an initial speed of 100 km/hr to 70 km/hr. before it impacts the nose of the MELT or ELT. The change in kinetic energy (ΔKE) of the 2000P vehicle (100 km/hr to 70 km/hr) is:
That is, if a GIAD device or devices absorb 385 kJ of energy of an impacting NCHRP 350 pickup truck's 3-31 test, then said pickup truck's follow-on impact with a MELT, ELT or G-1d type device would be at an NCHRP 350 2-31 test level and, taken as a whole, a MELT, ELT or G-1d type device plus a GIAD device, provides the utility of an NCHRP 350 TL-3 device.
That said, NCHRP 350 also requires any TL-3 terminal or crash cushion to pass the requirements of the abovementioned small car. This imposes an upper limit as to the deceleration (m/s, km/hr) allowable, under NCHRP 350, for a GIAD device.
Roadside safety devices, under NCHRP 350, have use-specific “preferred” and “maximum” deceleration limits. In the case of MELT, ELT or G-1d type devices, NCHRP 350, Chapter 5, Table 5.1. (report page 54), Item H. “Occupant impact velocities . . . should satisfy the following:” “Occupant Impact Velocity Limits (m/s)” Preferred 9 Maximum 12.
As identified in my 1999 crash test series, a GIAD device should address the need to neutralize vertical vector acquisition by impacting vehicles to ensure that impacting vehicles remain stable and preferably with tires in contact with pavement or ground. However, for ease of illustrative purposes only, the following discussion of GIAD device design limits, under NCHRP 350, will not express the vertical or 3rd dimension in the offered calculations, the reader being forewarned that the bumper height and/or center-of-mass difference between the NCHRP 350 small car and the NCHRP 350 pickup truck, in an impact on a GIAD device results in a positive vertical vector component not addressed herein.
A GIAD device is one or more energy-absorbing, thru tensile-tear and shear, structures, pitched in the direction of an impacting vehicle (so as to neutralize vertical vector acquisition). The engagement of an NCHRP 350 small car with a GIAD device must not result in a deceleration of more than 12 m/s or (12 m/s×(3600 s/hr)/1000 m/km)) 43.2 km/hr. At an initial velocity of 100 km/hr, and a deceleration of 43.2 km/hr, resulting in a final velocity of (100 km/hr-43.2 km/hr) 56.8 km/hr, an NCHRP 350 small car's Δ KE is:
FIG. 1 shows the present inventor's U.S. Pat. No. 6,367,208 FIG. 5 highlighting use of a post, modified to the present invention, the configuration having asymmetrical structural properties in lateral load conditions. The present invention's FIG. 1 shows post, 1, with a plastic component, 2, and two or more fiber, 3, reinforcing elements.
FIG. 2 shows the present inventor's U.S. Pat. No. 6,422,714 FIG. 7 showing a typical omni-directional “breakaway” post. The present invention's FIG. 2 shows post, 4, anchor-sleeve, 5, anchor-post-stub, 6, and typical ground-line, 7.
FIG. 3 shows the present inventor's U.S. Pat. No. 6,454,488's FIG. 1. The present invention's FIG. 3 shows modification incorporating the present invention's FIG. 1 with typical U-channel post material, 8.
FIG. 4 shows the present inventor's U.S. Pat. No. 6,935,622's FIG. 1 modifying the present invention's FIG. 1 to show stiffening by the addition of material, 9, with direction of intended lateral loading, 10.
FIG. 5 shows one of the present invention's embodiment in which the post is pitched in the direction of the intended lateral load and element 111 is added to maintain element 9 in a vertical configuration.
FIG. 6 shows one of the present invention's embodiment in which the post is pitched in the direction of the intended lateral load by providing a knee, 12, or bend, 12, in the post.
FIG. 7 shows one of the present invention's embodiment in which the post is pitched from the vertical, 13. Intended lateral loads 14 (with resultant moment-arm 15) and 16 (with resultant moment-arm 17) showing differences in bending moments at ground-line due to bumper heights of impacting vehicles.
FIG. 8 shows one of the present invention's embodiment in which the post is pitched from the vertical. The post has a discontinuance, 20, providing an asymmetric section modulus response to intended lateral load 19 and unintended lateral load 18. 21 shows an enlargement on discontinuance 20.
The present invention utilizes physical dislocations of structural elements to alter the load path(s) of externally imposed loads by changing the effective cross-section of an element via rotation to the imposed shear (shear diagram being constant) in combination with change in dynamic deflection, of a varying nature based on distance from the imposed load to the intended point(s) of structural failure, of the gross structure, thereby increasing the load-time of the imposed load(s). When steel is the material intended for structural failure, particularly “mild” steel, then the response to the imposed load(s), before the onset of structural failure, can be manipulated due to steel's radical increase in tensile strength when dynamically loaded. That is, steel, as a general statement, exhibits a 2 to 3 times increase in tensile load capacity when dynamically loaded vs its load capacity when statically loaded.
The present invention utilizes the initial kinetic energy of an imposed lateral load(s) regime, transferred thru a structure relatively stiff for the anticipated said load regime to rotate pre-determined, intended, region(s) of structural failure in the direction of the imposed load, with the act of said rotation changing the original shear-to-tensile ratio in favor of tensile tear as the failure mechanism.
To achieve greater rotation for anticipated greater load regimes imposed at greater elevations above the intended structural failure region, the structure above said failure region allows greater dynamic deflection before the full onset of the imposed load(s) regime on the intended structural failure region.
Restated, an individual structure anchored in a soil-matrix or foundation such as a reinforced concrete footing or similar anchorage, and so designed that when said structure structurally failed due to an imposed lateral load regime that failure occurs within the said structure and not the said soil-matrix or similar anchorage.
Said individual structure is structurally attached to said anchorage material via hardware configured with a predetermined change in cross-section resulting in a stress-concentrating geometry or a change in material which causes a change in stiffness in the imposed lateral load pathway (from the point(s) of loading(s) to the anchorage material) resulting in a stress-concentrating effect, or both.
Above-referenced change in cross-section or material or both allows for rotation of that part of the said structure in the same direction as the imposed lateral load(s). Said rotation changes the applied load(s) shear-to-tensile ratio in the region of the above-mentioned change in cross-section or change in materials or both. The greater the said rotation causing a change in structural failure mode from one dominated by shear to one less dominated by shear and more by tensile tear.
Said individual structure, above the said change, in cross-section or change in materials or both, allows greater dynamic deflection upon the imposition of said lateral load(s) regimes thereby allowing greater rotation before the onset of said load regime. Said greater dynamic deflection being greater with further distance from said change, in cross-section or material or both.
Structural failure results in the separated portion of the structure, above the physical point(s) of separation elevation having a center-of-mass above the elevation of the imposed lateral load(s) regime.
One of the present invention's embodiment consists of modifying existing present art devices intended to “breakaway” on impact to allow highway vehicles to NOT decelerate above a specific value. The present invention modifies these existing present art devices based on the present inventor's discoveries thru full-scale testing and the unexpected results from said full-scale test results. Said modifications are:
1). Directly addressing the development of positive vertical vector(s) on impacting vehicles, which encounter present art “breakaway” devices, by changing said devices' geometry relative to the path of the impacting vehicle by “tilting” or “leaning” the device toward the approaching vehicle. Said tilting causes the present art devices to “breakaway” before the impacting vehicles' begin to “climb” the devices. Multiple full-scale crash testing conducted both by and for the present inventor has established that ability to maintain, an impacting vehicle's front end (tires), contact with pavement both during and following the impact with the “breakaway” devices. Such stability of an impacting vehicle is not a requirement for “breakaway” devices but is a requirement of impact-attenuators. 2). Use of friction reducing material(s) on the face of the present art “breakaway” devices' surface(s) of intended vehicle impact also tends to reduce the impacting vehicles' development of a positive vertical vector by encouraging the impacting vehicles to develop a negative vertical vector during engagement with a present art “breakaway” device which is tilted in the direction toward an impacting vehicle. 3). Change in the section-modulus properties of the structural element(s) above the point of “breakaway” on present art “breakaway” devices to provide greater dynamic deflection, based on the elevation or height of the contact point of the impacting vehicle on said structural element so as to effect an increase in service-load-capacity of the device(s)' and thereby the device(s) deceleration effect on impacting vehicles. Restated, the present invention modifies present art “breakaway” devices so that higher roadway clearance vehicles experience greater deceleration due to their impact with a present invention device than a vehicle with a lower roadway clearance. Specific examples would be that a larger-mass pickup truck with a higher point of impact on a present invention device would experience a greater deceleration, per unit of mass, that a smaller-mass “small” car with a lower point of impact on the same present invention device. This difference in deceleration behavior of the present invention device(s) based on elevation of impact point is not taught in the present art and is significant in both the financial economy of the present invention device(s) and also the economy of the “footprint” required for the effective deployment of the present invention device(s).
A number of discoveries, in applying present art “breakaway” devices to the fields of impact-attenuators occurred during the present inventor's full-scale testing of Strizki patented devices, now open art, such as U.S. Pat. Nos. 3,637,244 (12/1972); 3,951,556 (4/1976); 3,967,907 (7/1976), and 4,071,970 (2/1978).
One of the present invention's embodiments, incorporating Strizki teachings, referenced above, consists of five distinct elements.
The first element is its structural attachment to a foundation such as an anchor plate bolted to a reinforced concrete footing or pile foundation.
Said anchor plate to structurally attached to a second plate (second element) by way of a third and a fourth element(s) which consist of a necked-down shank (which is the intended structural failure region) which is structurally attached to the first element (the anchor plate) and a bolt which passes thru an enlarged hole in the second plate.
The second element or plate is structurally attached to a fifth element, a structural member strong enough to not significantly deform locally on the imposition of a dynamic load such as the impact of a highway vehicle and to transmit said imposed load to the second element or plate.
Said fifth element has a varying section-modulus which decreases with the distance from the second element or plate and as such an imposed load from a small car with a relatively low point of impact will result in a smaller dynamic deflection before the third element (the intended region for structural failure) is fully loaded vs a pickup truck with a relatively high point of impact which will result in a significantly larger dynamic deflection before the third element (the intended region for structural failure) is fully loaded. This intentional change, in significant dynamic deflection based on elevation, changes the length of time taken to load the intended region for structural failure (the third element), and changes the tensile strength available to the steel material of the intended structural failure, to the imposed loads based on the distance of the imposed loads from the intended region of structural failure. This aspect of the fifth element changes the effect of the moment-diagram, of the imposed loads on the region of structural failure thru the use of the strength characteristics of steel vis-à-vis its “static-dynamic” load response nature.
The enlarged hole in the second element (second plate) thru which the fourth element (bolt) passes thru, allows rotation of the second element (necked-down shank) with the imposition of the imposed load. Rotation of the necked-down, intended region for structural failure, shank changes the cross-sectional geometry imposed by the load(s) shear-diagram. The greater dynamic deflection of the pickup truck and the associated longer load-time allows for greater rotation of the third element (necked-down shank) and increasing the amount of tensile elongation of the necked-down region before the combination of the shear and tension results in structural failure.
The result of the above configuration is that the small, lower to the ground, car's impact will result in a primarily shear failure of the neck-down intended region of structural failure, which results in a relatively low absorption of the imposed kinetic-energy, which the, higher off the ground, pickup truck's impact will result in a greater percentage of tensile tear failure in the necked-down intended region of structural failure, which results in a relatively higher absorption of the imposed kinetic-energy.
Finally, the preferred embodiment includes “pitching-toward”, “leaning-toward” or “tilting” in the anticipated direction of incoming vehicles of the fifth element so as to damp out the development of a vertical positive vector on the impacting vehicle.
The present invention's preferred embodiment incorporates some of the present inventor's existing U.S. patents and their teachings into expressions in the fields of the present invention, that of impact-attenuators. Said existing patents are: U.S. Pat. No. 6,367,208 and in particular, the use of dissimilar materials to achieve specific dynamic deflections under predetermined service-loads; U.S. Pat. No. 6,409,433 and in particular, the use of pre-stressing and/or port-tensioning of structural composites and said pre-tensioned or post-tensioned structural composites to achieve specific dynamic responses to applied service-loads; U.S. Pat. No. 6,422,714 and in particular, use of predetermined structural response to approaching vehicles and in reference to “breakaway” functions; U.S. Pat. No. 6,454,488 and in particular its teachings of energy absorbing aspects of sequentially shearing off of structural elements to effect a pre-determined rate of deceleration of a given vehicle for a given mass and velocity; U.S. Pat. No. 6,502,805 and in particular, its advantageous shear transfer to a soil-matrix foundation and its provided structural zones of weakness to provide an intended manner of structural failure; U.S. Pat. No. 6,561,492 and in particular its teachings on friction reduction and the consequences of such friction reduction; U.S. Pat. No. 6,685,154 and in particular its teachings of structural composites as resultant static and dynamic responses to service-loads; and U.S. Pat. No. 6,892,502 and in particular to utilization of structural composites in bearing as load transmission structures; and the present inventor's 20050252165, filed Feb. 2, 2005 and its teachings of structural composites consisting of elements exhibiting significant asymmetric engineering properties.
While many of the present art “breakaway” devices may be modified to address the significantly different requirements of impact attenuators generally and gating impact attenuators particularly, it is economically undesirable to combine both the utility of a highway sign structure “breakaway” and the utility of a gating impact attenuator, in addition to the problems associated with Federal highway Administration's required engineering design requirement incompatibilities of achieving the same utility from a single device configuration.
The present invention's preferred embodiment is a structural composite composed of two (2) or more elements forming a post affixed at or near ground-line with the two (2) elements attached and extending upward from said ground-line. The first element being nearest oncoming vehicular traffic which the device is intended to decelerate. The second element is not continuous and provides not tensile load capacity when the top of the device is bent in the direction of said oncoming vehicular traffic which the device is intended to decelerate. That is the device has significant asymmetric structural properties parallel with the flow of vehicular traffic, upstream and downstream. The device is tilted toward oncoming vehicular traffic which the device is intended to decelerate. The device has friction reducing surfaces facing the oncoming vehicular traffic which the device is intended to decelerate. The center-of-mass of the portion of the device, above ground-line, is above the intended contact-point-elevation on the device of an impacting vehicle.
The gap, caused by the dis-continuality of the second element, has geometry such that when the device is laterally loaded at an elevation significantly above ground-line, the device will rotate in the direction of the load and thereby close said gap which results in a change in the said load's resultant vector-couple from that resisted only by the first element to that of a resultant vector-couple utilizing the extreme fiber of both the first and second elements. When the device is laterally loaded at a significantly lower elevation, the devices structurally fails primarily in shear of the first element in the near region of the aforementioned gap in the second element.