EP0161332A1 - Elastomere Fahrbahnmarkierung - Google Patents

Elastomere Fahrbahnmarkierung Download PDF

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Publication number
EP0161332A1
EP0161332A1 EP84111987A EP84111987A EP0161332A1 EP 0161332 A1 EP0161332 A1 EP 0161332A1 EP 84111987 A EP84111987 A EP 84111987A EP 84111987 A EP84111987 A EP 84111987A EP 0161332 A1 EP0161332 A1 EP 0161332A1
Authority
EP
European Patent Office
Prior art keywords
pavement marker
marker
base
raised surface
diamond
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP84111987A
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English (en)
French (fr)
Other versions
EP0161332B1 (de
Inventor
Thomas D. C/O Minnesota Mining And Krech
David C. C/O Minnesota Mining And May
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from EP84302441A external-priority patent/EP0125785B1/de
Application filed by Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
Publication of EP0161332A1 publication Critical patent/EP0161332A1/de
Application granted granted Critical
Publication of EP0161332B1 publication Critical patent/EP0161332B1/de
Expired legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F9/00—Arrangement of road signs or traffic signals; Arrangements for enforcing caution
    • E01F9/50—Road surface markings; Kerbs or road edgings, specially adapted for alerting road users
    • E01F9/553—Low discrete bodies, e.g. marking blocks, studs or flexible vehicle-striking members
    • E01F9/565—Low discrete bodies, e.g. marking blocks, studs or flexible vehicle-striking members having deflectable or displaceable parts
    • E01F9/573—Self-righting, upright flexible or rockable markers, e.g. resilient flaps bending over
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F9/00—Arrangement of road signs or traffic signals; Arrangements for enforcing caution
    • E01F9/50—Road surface markings; Kerbs or road edgings, specially adapted for alerting road users
    • E01F9/553—Low discrete bodies, e.g. marking blocks, studs or flexible vehicle-striking members
    • E01F9/565—Low discrete bodies, e.g. marking blocks, studs or flexible vehicle-striking members having deflectable or displaceable parts
    • E01F9/571—Low discrete bodies, e.g. marking blocks, studs or flexible vehicle-striking members having deflectable or displaceable parts displaceable vertically under load, e.g. in combination with rotation

Definitions

  • This invention pertains to pavement markers used in delineating traffic lanes on highways.
  • pavement markings have fallen into three basic classes:
  • Raised pavement markers offer a greater degree of night delineation or retroreflection, wet or dry, than is offered by painted lines and tapes.
  • Most commercial forms of raised lane delineators comprise a flat-bottomed disk or base (ceramic, polymeric or metal) having a raised portion which carries a reflector portion made of reflective glass microspheres or cube-corner reflector inserts. After the passage of time, these devices can move or slide out of position under the repeated impact of vehicle wheels.
  • Raised markers or delineators have found wide application in road markings, but their application would be even wider except for some disadvantages, specifically: cost (more expensive than tape or reflective paint), poor durability (broken upon impact, scratched reflective surface, etc.) and placement, requiring curable adhesives (epoxy), holes or anchors to remain in place. In geographic areas in which roadways must be plowed to clear them of snow, such lane delineators are quickly removed by the plowing operation. Furthermore, raised markers made of a hard or heavy material could cause property damage and injury if they were thrown into the air by a snowplow, e.g., breaking a passing motorist's windshield.
  • Some known pavement markers have a raised rubber reflecting portion or tab which is intended to bend over under a vehicle tire. Others have a reflecting portion which is supposed to retract into a recess in the pavement.
  • the former type is illustrated by U.S. Patents 4,111,581; 3,963,362; 3,879,148; and 3,785,719.
  • the reflecting portion is a flat reflectorized rubber piece or tab rising above the pavement surface. The tab is supported at its bottom by attachment to the base portion.
  • the object of this invention is a raised pavement marker offering a high degree of reflectivity, low cost, ease of placement with adequate durability, and safety while alleviating the support and creasing problems of prior raised rubber markers.
  • Another object is to provide a preformed tape offering the same advantages of high reflectivity, low cost, and good durability.
  • a roadway marker which comprises a body having an approximately flat base portion which can be attached to a roadway, and which has a raised surface adapted to face oncoming traffic when the marker is mounted on a road, and a reflective material attached to said raised surface, said body being made of an elastomer and having a compressive strength (see ASTM specification D1056) at 25 percent compression of less than about 14.5 pounds per square inch (about 100 kPa). That is, a compressive force of less than about 100 kPa will compress the material 25%. Normally its compressive strength at 25% compression is at least 6 psi (41 kPa). Compressive strength is measured by ASTM test specification D1056.
  • a soft, easily compressed elastomer preferably a sponge or cellular polymer (cellular rubber)
  • a retroreflective film may be applied to the foam to provide the desired reflective properties.
  • Pavement markers tested in reducing this invention to practice exhibited brightness far beyond conventional paints or tapes, and similar to that of known raised pavement markers. In addition, these markers reflected effectively both wet and dry.
  • markers may also utilize pressure-sensitive adhesive on the bottom for adhering to the road surface, making their placement very easy by simply pressing them to the surface.
  • the uncompressed marker height is normally in the range of 5 mm to 25 mm, and is preferably no greater than 20 mm.
  • Reflective tapes for such purposes as lane delineation can take advantage of the same principle. That is, they can be made of slightly raised foam or cellular polymer which easily compresses under the weight of a vehicle tire. Preferably, the total thickness of the tape is up to about 2.5 mm maximum. With ordinary tapes, much of the frictional force from a vehicle tire are believed to be transmitted to the interface between the adhesive and the road. Known tapes can smear, break or slide under these forces, e.g. the shear stress created by a tire being turned on a tape. The cellular polymer would dampen these applied forces, reducing the effect on the adhesive interface.
  • the tape could be produced by cutting a strip of foam polymer from a cylinder of such material and applying a reflective layer to the strip. The reflective (preferably retroreflective) layer could be applied by reverse roll coating polyurethane to the foam strip and next placing glass beads on the polyurethane while it is still wet.
  • a pressure sensitive adhesive may be placed on the bottom surface for adhereing to
  • the type of raised pavement markers disclosed herein may be produced at very low cost, thereby allowing placement of a series of numerous markers so drivers would see a continuous stripe along the road. Where reflector height is 9.5 mm and viewing distance is about 61 meters the markers should be placed at about 760 mm intervals for E reflecting from automobile headlights.
  • FIG. 1 shows the components of one embodiment of this invention.
  • Item 2 is an elastomeric body, for example made of a sponge elastomer such as polyurethane, silicone rubber, ethylene propylene diene terpolymer (EPDM), neoprene or blends of EPDM and neoprene.
  • Adhesive layer 3 is attached to the base of the body, and reflecting material 4 is attached to the raised reflecting surface portion 5 of the body.
  • a surprisingly small amount of adhesive is necessary to hold these flexible foam markers on the road (e.g., peel strength of 4.2 pounds per inch, 0.74 kN/m).
  • the angle e between the reflecting surface and the base (or between the reflecting surface and the road surface) is usually between 45 and 135°, preferably between 45 and 90°.
  • Reflecting portion 4 is preferably thin retroreflective sheet comprising a polymeric support sheet in which a monolayer of transparent microspheres or beads are embedded to slightly more than half their diameter.
  • the glass beads carry a coating of reflective material such as aluminum over their embedded surfaces.
  • the reflector support sheet has a layer of adhesive on the back by which it is adhered to the pavement marker body as shown.
  • enclosed lens sheeting appears to perform best (i.e., glass beads covered by a clear polymer layer) although an exposed lens sheeting and cube corner reflectors may also be used.
  • Reinforcement may be used within the body (e.g., fiberglass fabric or fibers) to strengthen the markers.
  • the pavement marker bodies of this invention can be made by an extrusion process.
  • the manufacture of cellular or sponge rubbers in an extrusion process is known.
  • the uncured elastomer is generally compounded with vulcanizing chemicals and a blowing agent at a temperature below the decomposition temperature of the blowing agent.
  • a suitable EPDM sponge rubber is described in Borg, E.L., "Ethylene/Propylene Rubber", in Rubber Technology, 2d ed., Morton, M. ed., Van Nostrand Reinhold Company, New York, 1973, at pages 242 and 243. Further description of sponge rubber is found in Otterstedt, C.W., "Closed Cell Sponge Rubber", in The Vanderbilt Rubber Handbook, R.T. Vanderbilt Co., Inc., Norwalk, Conn., 1978, at pages 728-729.
  • the compound is extruded through a die of specified shape.
  • the extrudate is then cured and simultaneously expanded at elevated temperature. Curing may be done in a brine bath at about 204°C.
  • a reflective (preferably retroreflective) film is applied to the raised surface adapted to face oncoming traffic, generally by use of an adhesive such as a pressure sensitive adhesive.
  • the retroreflective film is preferably of the type known as wide angle flat top sheet which comprises: a back reflector; an overlying transparent matrix; a light-returning layer of small transparent spheres embedded in the transparent matrix in optical connection with the back reflector but spaced from it a distance to increase substantially the brilliance of reflected light; and a transparent overlying solid covering and conforming to the front extremeties of the spheres and having a flat front face.
  • Such sheeting reflects a cone of light back toward a light source, even though the incident beam strikes the reflector at an angle other than perpendicular to the sheeting.
  • U.S. Patent 2,407,680 The transparent film occupying the space between the spheres and the reflector is called the spacing film.
  • This wide angle flat top sheeting can be considered an embedded lens or enclosed lens sheeting having a spacing film or layer with a thickness which locates the back reflector at the approximate focal point of the optical system.
  • Wide angle flat top retroreflective sheeting may be made, for example, by a solution casting technique comprising the following process steps: (a) providing a paper carrier web coated with a release agent such as polyethylene; (b) a coating the release agent side of the carrier web with a 25% solids solution of fully reacted aliphatic elastomeric polyurethane of the polyester type in an isopropanol, toluene, xylene solvent (e.g., QI3787 from K. J.
  • a solution casting technique comprising the following process steps: (a) providing a paper carrier web coated with a release agent such as polyethylene; (b) a coating the release agent side of the carrier web with a 25% solids solution of fully reacted aliphatic elastomeric polyurethane of the polyester type in an isopropanol, toluene, xylene solvent (e.g., QI3787 from K. J.
  • a polyurethane hard coating may be applied to the front surface of the sheeting to reduce the accumulation of dirt on the sheeting in use.
  • Such a hard coating has a generally tack-free surface and substantially higher 100% modulus of elasticity and lower ultimate elongation than the polyurethane used for the transparent matrix in the reflective sheeting.
  • a typical suitable hard coat polymer is K. J. Quinn 013515 having a 100% modulus of 5840 psi (40.2 MPa) and 210% ultimate elongation, fully reacted aliphatic elastomeric polyurethane of the polyester type.
  • the polyurethane polymers used for the transparent matrix and spacing layers are useful because they are somewhat elastic and can follow the movement of the pavement marker body without delaminating.
  • an adhesive is applied to the bottom surface of the marker body.
  • it is a phenolic modified polybutadiene pressure sensitive adhesive at least about 250 microns thick cast on a disposable (paper) liner. The liner is removed prior to placement of the marker on the road surface.
  • the markers may be applied to the road by at least two methods.
  • One such method is removing the adhesive liner and pressing the marker to the road surface or onto other marking materials (tape or paint).
  • a second method comprises applying the markers to a tape which is thereafter applied to the road.
  • Hollow cross-section markers may help to dissipate the heat of compression better than solid foam, and they may compress better, offering less resistance to vehicles travelling over them.
  • One hollow prototype of this invention was the D cross-section of FIG. 3.
  • body 8 had reflecting layer 11 adhered to its curved surface and adhesive layer 10 adhered to its straight side.
  • water can become entrapped within the hollow cross-section, and the rapid, repeated compression under vehicle loading may cause rupture at any weak points.
  • marker shapes of this invention provide some form of lateral or back support for the reflector, unlike the markers with raised reflective rubber tabs discussed in the background section.
  • the body has a connecting portion which joins the base and the back side of the raised surface which it supports.
  • the marker of FIG. 1 supports the whole back of the reflector 4 with raised body portion 5.
  • the reflecting portion is not simply a thin pliable tab in the roadway, as with the older designs.
  • the connecting portion forms an acute angle with the plane of the bottom of the base portion and has two ribs located on the hack side of said connecting portion oriented parallel to the plane of the hasp. More than two such ribs can be used.
  • FIG. R An alternative embodiment of the invention, shown in FIG. R, comprises an elastomeric body with the compressive strength and base as described above but having:
  • the marker should be placed so that there is at least one protective rib located in front of raised surface adapted to face oncoming traffic.
  • the height of the protective rib is generally a minimum of 45% of the height of the diamond-shaped portion, as measured from the bottom of the base. However, it should not be so high as to obscure the reflecting material.
  • the ribs are believed to protect the diamond-shaped portion from stress concentration which would hasten its deterioration. Thus the protected diamond shape should have a longer service life.
  • the characteristic of lying flat under a load is obtained using the sponge rubbers described previously. It can also be attained by using normal vulcanized rubbers in a hollow configuration.
  • the hollow diamond-shaped protion is joined to the base along the line defined by one of the corners of the diamond shape and is oriented so that at least one of its surfaces is a raised surface adapted to face oncoming traffic.
  • the reflecting layer is adhered to at least one such surface.
  • the back of the reflecting surface is inherently supported at the top and bottom by the portions of the diamond that connect to it at an angle.
  • the two protective ribs running parallel to and on opposite sides of the elongated sides of the diamond extend the life of the marker over that of similar designs without the ribs.
  • the aspect ratios (width at the widest point divided by height) for the diamond shape and the ribs are preferably in the ranges of 0.6 to 1.0 and about 1 to 1.3 respectively. Height of the diamond shape is measured from the point where it joins the base, and height of the ribs is measured from the bottom of the marker.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Road Signs Or Road Markings (AREA)
EP84111987A 1984-04-10 1984-10-05 Elastomere Fahrbahnmarkierung Expired EP0161332B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP84302441 1984-04-10
EP84302441A EP0125785B1 (de) 1983-04-11 1984-04-10 Elastomere Fahrbahnmarkierung

Related Child Applications (1)

Application Number Title Priority Date Filing Date
EP88100849.4 Division-Into 1984-10-05

Publications (2)

Publication Number Publication Date
EP0161332A1 true EP0161332A1 (de) 1985-11-21
EP0161332B1 EP0161332B1 (de) 1989-02-01

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Family Applications (1)

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EP84111987A Expired EP0161332B1 (de) 1984-04-10 1984-10-05 Elastomere Fahrbahnmarkierung

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EP (1) EP0161332B1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3719261A1 (de) * 1987-06-10 1988-12-22 Klasen Geb Tesdorff Renate Strassenmarkierung
WO2007141357A1 (es) * 2006-06-06 2007-12-13 Empresa Municipal De Transportes De Madrid, S.A. Módulos para separadores de carril bus -taxi

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2414044A1 (de) * 1973-03-21 1974-10-03 Ludwig Eigenmann Rueckreflektierende vorrichtung zur verbesserung der sichtbarkeit unter rasantem licht von bodenmarkierungen
DE7136160U (de) * 1970-09-21 1974-11-28 Minnesota Mining And Manufacturing Co Überfahrbares Straßenmarkierungselement
US3963362A (en) * 1974-11-27 1976-06-15 Carlisle Corporation Road marker
US4111581A (en) * 1978-01-03 1978-09-05 Auriemma Robert S Highway marker
US4203685A (en) * 1978-05-05 1980-05-20 Sanchez Richard E Automotive vehicle speed arrestor
DE2903215A1 (de) * 1979-01-27 1980-07-31 Debuschewitz Kg H Bodenrueckstrahler
EP0125785A1 (de) * 1983-04-11 1984-11-21 Minnesota Mining And Manufacturing Company Elastomere Fahrbahnmarkierung

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7136160U (de) * 1970-09-21 1974-11-28 Minnesota Mining And Manufacturing Co Überfahrbares Straßenmarkierungselement
DE2414044A1 (de) * 1973-03-21 1974-10-03 Ludwig Eigenmann Rueckreflektierende vorrichtung zur verbesserung der sichtbarkeit unter rasantem licht von bodenmarkierungen
US3963362A (en) * 1974-11-27 1976-06-15 Carlisle Corporation Road marker
US4111581A (en) * 1978-01-03 1978-09-05 Auriemma Robert S Highway marker
US4203685A (en) * 1978-05-05 1980-05-20 Sanchez Richard E Automotive vehicle speed arrestor
DE2903215A1 (de) * 1979-01-27 1980-07-31 Debuschewitz Kg H Bodenrueckstrahler
EP0125785A1 (de) * 1983-04-11 1984-11-21 Minnesota Mining And Manufacturing Company Elastomere Fahrbahnmarkierung

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3719261A1 (de) * 1987-06-10 1988-12-22 Klasen Geb Tesdorff Renate Strassenmarkierung
WO2007141357A1 (es) * 2006-06-06 2007-12-13 Empresa Municipal De Transportes De Madrid, S.A. Módulos para separadores de carril bus -taxi

Also Published As

Publication number Publication date
EP0161332B1 (de) 1989-02-01

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