A prefabricated road surface marking tape material consisting of a factory prefabricated and assembled structure comprising a tape component and a plurality of retroreflective sheltered elements bulging above said tape, spacedly distributed lengthwise of the tape, and secured thereon in a such position that the light emitted by headlamps of a vehicle travelling on the road in the direction of the tape and impinging on said reflective means comprised in each element, will be retroreflected in form of a relatively narrow beam of light precisely directed towards the driver of the vehicle, for improved nighttime visibility of the sign.
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9. A prefabricated road-surface marking tape, comprising a tape adapted to be placed on and secured to a road surface to form a traffic aid thereon; a plurality of reflectors spaced lengthwise of and upwardly projecting from an upper face of said tape, each of said reflectors comprising a casing having a generally planar base portion of a first width and having a bottom face juxtaposed with said upper face, and a receiver portion of a smaller second width projecting upwardly from said base portion, and optically reflective elements sheltered in said receiver portion and operative for retroreflecting a relatively narrow beam of light lengthwise of said tape in one direction when impinged by vehicle-emitted light rays travelling in the opposite direction; and means including a plurality of recesses in said bottom face and accommodating portions of said tape therein, for fixedly anchoring said reflectors to said tape.
1. A prefabricated road-surface marking tape, comprising a tape adapted to be placed on and secured to a road surface to form a traffic aid thereon; a plurality of reflectors spaced lengthwise of and upwardly projecting from an upper face of said tape, each of said reflectors comprising a casing having a generally planar base portion of a first width and having a bottom face juxtaposed with said upper face, and a receiver portion of a smaller second width projecting upwardly from said base portion, and an optically reflective element mounted and sheltered in said receiver portion and operative for retroreflecting a relatively narrow beam of light lengthwise of said tape in one direction when impinged by vehicle-emitted light rays travelling in the opposite direction; and means including a plurality of recesses in said bottom face and accommodating portions of said tape therein, for fixedly anchoring said reflectors to said tape.
2. The road surface marking tape of
3. The road surface marking tape of
4. The road surface marking tape of
6. The road surface marking tape of
7. The road surface marking tape of
8. The road surface marking tape of
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1. Field of the Invention
This invention relates to the art of forming traffic regulating signs or strips on roadway pavements and, more particularly, to providing a roadway pavement with traffic regulating and facilitating means such as traffic lanes dividing lines, roadway edge dividing lines and the like, by applying and securing on the roadway pavement surface a factory prefabricated tape material.
More specifically this invention concerns the art of forming traffic regulating signs and lines formed with prefabricated tape material the upper face of which is provided with retroreflective or retrocollimating elements capable of ensuring nighttime visibility at a safe visibility distance when the substantially sole source of light is provided by the headlamps of motor vehicles which travel along the road, that is a source of light the rays of which impinge on the tape surface at spots well in advance of the position of the vehicle, and travel in a direction which forms either a small or a very small angle with the generally planar surface of the roadway pavement and of the marking tape applied thereon.
2. Description of the Prior Art
This art is a well worked one and a wide patent literature describes several embodiments of this art. Various procedures, machines and compositions have been proposed for expediting the prefabrication of such tape materials and retroreflective means and applying and adhesively securing said material on and to a suitably prepared roadway pavement. The U.S. Pat. Nos. 3,587,415, 3,879,148 and 3,958,891 (corresponding to British patent specifications Nos. 1,245,834, 1,465,585 and 1,459,273), of the present applicant, are examples of such literature.
Traffic safety evidently depends on the above considered safety visibility distance at which brilliant spots provided by the retroreflectivity of individual retrocollimating elements can be clearly and unmistakeably seen by the vehicle's driver. The brilliancy of such spots depends on the efficiency of the retroreflecting means and is proportional to the effective cross-sectional area of the impinging and reflected beam of rays (that is the actual operatable impinged area). The amplitude of this area is therefore a most important factor.
Other means have been proposed and are currently produced and made use of for improving the visibility of roadway edge delineations at a distance. Such means, commonly indicated by the simple term "markers", consist of a sturdy generally metallic structure wherein one or more light reflective elements are accommodated and at least partially sheltered against traffic wear. Such markers are generally bulky and promote dangerous jerks in rapidly traveling vehicles which pass over them (such markers provide a valuable aid when delineating roadway edges, pedestrian crossings and the like, but they are undesirable say along highways and traffic lane dividing lines).
Such markers are costly, as to their manufacture and to their laying on and securing to the roadway pavement. Each marker is necessarily individually placed in its required location and requires working of the conglomerate or aggregate pavement composition. Even if mechanical tools can facilitate the operation, the securing of individual markers requires competent workmen and involves substantial labour.
On the other hand the provision of sharply bulging retroreflective elements comprising efficient light reflective components having a substantial reflective area exposed to grazing light impingement, is advantageous when considered from the sole point of view of nighttime visibility at a distance, and also in rainy weather, when a layer of water is formed upon the road surface and covers only slightly bulging retroreflective elements, preventing retrocollimation.
It is therefore an object of this invention to provide a new useful material which can be associated with a roadway pavement and which provides, in combination, the advantages of both the well known prefabricated road marking tape materials having retroreflective element secured thereto, and of markers having efficient retrocollimating elements provided with a large (proportionally to their dimensions) effectively impinged area and bulging height.
According to the broadest aspect of the invention, there is provided a factory prefabricated composite roadway surface marking tape material comprising a tape component designed to be superimposed and firmly secured to a roadway surface to form a traffic aid thereon, and having an upper face, and a plurality of protrusions distributed lengthwise along said upper face at spaced locations, each protrusion consisting of one both retroreflective and structurally traffic resisting element having a base portion fixedly secured to said tape component, an optically reflective portion secured to and at least partially sheltered in a component integral with said base portion and positioned in said component for protruding above said upper face for impingement and retroreflection of light rays in a direction generally longitudinal of the tape and forming a very small angle with the road surface.
The thus prefabricated composite tape material, wherein the bulging retroreflective protrusions have been factory applied and secured to the tape component, can be readily wound in coils for storage and transportation to the locations where it is supposed to be applied, and its application on the road can be performed in the manner and by taking advantage of the known mechanical facilities used in the art of applying conventional road marking prefabricated road marking tape materials.
According to possible embodiments of the invention, the elements each comprise a properly structural component having the said base portion and one or more recesses integrally formed for housing the properly optical component or components. Said components can be made of polymeric compounds and connected to each other by adhesives, such as epoxies, or preferably by ultrasonic welding.
The structural component can be made of a highly stress resistant and suitably resilient resinous material such as a German (Western) patent applications No. 76 24805 and respectively P 26 32 107.3 (corresponding to the U.S. patent application Ser. No. 705,596, filed July 13, 1976) of the present applicant, can be seated in the structural component, adjacent to the lower edge portion of the retroreflective tablet 22, in an element of the type shown in FIGS. 4 to 6.
Briefly summarizing the above described invention, it is evident that the invention provides very important advantages, both as to economy of producing and applying a highly efficient road marking material and as to the safety of traffic ensured by the actual use of same material. Namely:
(i) The road marking material can be completely factory produced, assembled and prepared in coils or in stocks of piled lengths for storage and transportation. The thus prepared material can be laid on and adhesively secured to the road pavement so that a complete highly efficient material having daytime and nighttime visibility is formed without further operations, by taking full advantage of the known machines, apparatuses, procedures and compounds actually available for applying road marking tape materials.
(ii) The critical features that the retroreflective elements are factory associated to the tape component ensures that such elements are uniformly and exactly positioned and oriented in the direction defined by the same tape component (or at a predetermined given angle therewith). The narrow beams of light individually retroreflected by the elements are therefore perfectly directed for their visibility by the vehicle drivers, simply by the laying of the prefabricated composite material of the invention.
(iii) The optical reflective portion of each element is capable of retroreflecting substantially the entire amount of light impinging thereon. Generally, the source of light (the vehicle headlamps) it is at a relevant distance from the impinged elements and therefore the impinging rays are nearly parallel. The retroreflected light is consequently limited and confined in a substantially narrow beam. The above commented critical exact orientation of the optical reflective portions present on the road directs and concentrates the respective reflected beams towards the vehicle drivers for best exploitation of the available and retroreflectable luminous energy.
The perfect orientation of the retroreflected beams, resulting from the critical feature mentioned above at (ii) and from the easily obtainable directionality of the tape material being laid on the road pavement, provides an unexpectedly good nighttime visibility at distance, as confirmed by extensive experimentation, both in fair and in rainy weather.
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| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Jul 31 1989 | EIGENMANN, LUDWIG | Minnesota Mining and Manufacturing Company | ASSIGNMENT OF ASSIGNORS INTEREST | 005152 | /0337 |
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