Road signs having high refractive power

Abstract: Signalling stripes on the roadway, realized with paint or similar material, include reflectors, or similar refracting objects, partly mixed up in said material at distances and with variable inclinations according to the type of roadway, the kind of signals, or other, in such a way to assure a good visibility of the stripes even in conditions of rainy or, generally, of poor visibility.

Description: The present invention concerns road markers having high refractive power. As well-known the road markers painted an the roadway include transversal, longitudinal markers and other markers. The transversal and longitudinal markers consist of discontinuous and continuous stripes made with paint or other materials having the same efficacy; they must have such features to be well visible both by day and at night. In particular it is established that the traffic markers painted on the road surface which have to be visible during the night, must be refracting; to achieve such a purpose two different techniques are today employed, both using glass microballs which are premixed together- with the paint or are sprayed on the wet painted stripes. The former of the said techniques is more economic than the latter but it does not offer the same efficacy; in fact the microballs come up on the surface of the stripes, only by degrees in the long run, owing to the continuous abrasive action of the road traffic. On the other hand, with the technique of the spray painting of the microballs, not only one has to support high costs but moreover the efficacy lowers rapidly because of the inevitable continuous removal of the microballs. It is clear that the eventual combination of the two said techniques might produce good results in terms of wear and efficacy; but, besides having a higher cost, this last solution would not be suitable for guaranteeing the refraction of the incident rays, and so the visibility of the stripes, when it happens that these ones are under the thin layer of water which is present on the road when it rains or in conditions of high environmental humidity. As far as this problem, some solutions have been recently introduced and tested. They present some projections made transversally on the stripes, at regular intervals; these projections have enough height to emerge from said layer of water and so they are able to make the location of the signal stripe right, since, like the stripe, they are made refracting by means of one of the above mentioned techniques. However, the above seen problems pertinent to the continuous abrasive action of the traffic, to the consequent removal of the microballs and so to the loss of efficacy of the signal system in bad environmental conditions remain also with this type of solution. Therefore it is necessary to use further and expensive signalling refractive devices put at the side of the road or fastened on the roadway itself through adhesives or through plastic bulbs or similiar devices directly fixed to the asphalt. US-A-4 069 281 describes a roadway surface marking strip material having a base layer and an upper layer, wherein said upper layer comprises an upper face which forms the marked area and has a number of protuberances spaced lengthwise of the strip material and a plurality of retroreflective elements secured to ends seated on said traffic contactable upper face, providing in this way both nighttime visibility and non-skid properties to said marked area. The object of the present invention is to propose a road markers painted on the road surface having high refractive power also in bad environment conditions and which maintain this particular efficacy for a long time. Said object is achieved by a road marker as defined in claim 1. To better understand the features of the present invention non-limitative examples of embodiment are disclosed in the herewith enclosed drawings, whereby: Figure I shows a stretch of the signal stripe according to the invention, seen from the above; Figure 2 shows a view in section, realized according to the line II - II , of the stripe shown in figure I; Figure 3 shows an enlarged transversal part of the signal stripe of figure I; Figure 4 shows an enlarged view in section, realized according to the line IV - IV of figure 3; Figure 5 shows a view from the above of a second example of realization of a signal stripe according to the invention; Figure 6 shows a view from the above of a third example of realization of a signal stripe according to the invention; Figure 7 shows a different execution of the signal stripe of figure I; Figure 8 shows an enlarged part of the signal stripe shown in figure 7; Figure 9 shows a further example of realization of a signal stripe according to the invention, made transversally on the roadway instead of lengthwise like for examples shown in the figures from I to 8. Referring to figure I, it is indicated with I0 a signal stripe put lengthwise on the roadway II, near the right edge with regard to direction I2 of the traffic on said roadway. In this example, the stripe I0 represents a continuous stripe made with a yellow coloured paint, used to signal the border of the roadway, or to detect this one from the adjacent cycle tracks, from the sidewalks, from the laybies. On said stripe I0, we can see some projections I3 put in a uniform way and arranged transversally on it; said projections are made up with the same paint the stripe is painted with. Mixed up with the paint, corresponding to the projections I3, there are indicated some reflectors with I4, better illustrated in the following figures 3 and 4; said reflectors are lined up along the stripe I0, and they are turned, with their refracting part, towards the coming direction of the traffic along the roadway II. We can see the right inclination, both in the horizontal and the vertical plane, of reflectors I4 in the figures 3 and 4. As well-known, the reflector I4 is formed by a biconvex spherical lens between two concentric surfaces I5 and I6, bent in such a way that any incident luminous ray over the benter surface, I5, reflects itself over the other surface, I6, which is silvered, in such a way as to be reflected into the direction of the incident ray. In the example shown in figure 4, the middle axis I7 of the reflector I4 is properly inclined up in such a way that the angle of refraction of the reflector specified by the two lines, I8 and I9, passing through the common centre of bending 20 of the surfaces I5 and I6, effects the zone over the roadway II. In figure 3 we can also see that said middle axis I7 lies on a plane whose horizontal trace, coinciding with the section line IV - IV, is inclined of an angle α compared with the direction of the stripe I0; even if it is not essential to the efficacy of the invention and even if it is not so useful as the vertical inclination shown in figure 4, this solution is preferable when the road traffic runs completely at the left of the stripe I0. In particular, if the invention was applied in situations where the road traffic runs only on one side of the signal stripe, then it should be more useful to switch to the solution shown in figure 5, where it can remarked that the best position of the reflective angle of the reflectors is obtained not by the simple inclination of the reflectors themselves with respect to the stripe I0; in fact, it might be more immediate, and so cheaper, to put, during the realization of the stripe, the projections in an inclined position on it than to put each reflector in an inclined position an the projections I3. This last can be obtained using a technique of production of the modulus type; in fact, maintaining the principle that according to the invention the reflectors are mixed up directly with the paint, the projections, with the reflectors, are, according to said technique, prepared before and then, once dried, they are put on the stripe during the making of this one or, afterwards, glueing them, too. For this reason, the above mentioned technique of production allows to realize easily signal stripes in which the reflectors must be cut according to some particular preferential directions. A further example of these applications is shown in figure 6, in which we can see that the projections I3 are put on the stripe I0 in turn in a perpendicolar position and in an inclined one with respect to the direction of the stripes; such a disposition might be useful, for example, in the motor-way signalling system to signal the right margin of all the gangways for the usual road traffic, said margin being delimitated by a yellow coloured continuous stripe and forming a boundary for a further emergency gangway situated at the right of said stripe which, for this reason, has to be visible from both sides and with better efficacy from side where the road traffic usually runs. Other examples of the present invention, shown in the figures 7, 8, and 9, refer to the possibility to mix the reflectors, or the similar refracting objects, with the projections, 22, having a shape of half-spheres and disposed along the stripes 23 and 24; said projections 22 being made up with paint, or similar material, when the stripe is painted or preliminarly, like for the projections I3 above described. The displacing of the reflectors I4 into the material forming said projections 22 is made either when the stripe has being executed or when the projections themselves 22 are being produced. It is very useful to employ spherical bowl projections 22 in the manufacture of signal stripes disposed transversally on the roadway; as well-known, they are situated near the cross-roads where there is no right of precedence and however they are situated where vehicles must stop, like in the entry areas of the motor-ways. Some projections 22, along the stripe, even if at regular intervals, would not be a great obstacle to the road traffic as some continuous projections, like projections I3, are and they might contain a good whole of refracting reflectors according to the invention; in the meantime they would be a barrier of small obstacles useful to warn the driver when he gets over them. Other examples of practical embodiment of the present invention can be realized besides those above described. This signalling system is very effective thanks to the use of items with a great refracting power like the reflectors; moreover, it is capable of maintaining for a long time said efficacy thanks to the fact that the reflectors themselves are well mixed up in the paint which constitues the signal stripes; for this reason, we can have a low cost of production compared with the signalling system in which projections or bulbs are used in a different material from the one used for the stripes. Of course, the height of the projections, both the transversal bump type and the spherical bowl type, can be varied; in fact, the real dimensions of the reflectors can be smaller to the ones of the reflector-I4 illustrated in figure 4, which is here enlarged to better show it. The numbers of the reflectors, or the similar refracting objects having equal efficacy, can be smaller or larger than the ones of the shown examples according to the applications and the environment in which they are put. The distance between the projections which contain the above refracting objects can also be varied so that it can clearly indicate the presence of the signal stripe in any environmental condition and whatever the speed of the vehicle which is going along the roadway, is. A further advantage derived from the technique of the present invention is the swiftness to execute the stripes with the refracting objects and so the smaller obstacle to the road traffic which, on the contrary, derives from the existing methods.

Claims: Road marker for road surfaces comprising signal stripes (19) realised with paint or an equivalent material, and projections (13) disposed at spaced intervals along said stripes (10), said projections (13) being of the same material as said signal stripes (10) and including reflecting elements partly mixed in said paint or equivalent material, said reflecting elements being provided on the upper surface of said projections (13) in such a way as to be able to reflect incident luminous rays, characterised in that each of said reflecting elements comprises a reflector (14) formed by a bi-convex lens defined by two part-spherical surfaces (15,16) of differing radii but having a common focal point, the surface (16) of greater radius being silvered so that luminous rays incident onto the reflectors (14) will be reflected by the silvered surface (16) back through the surface (15) of smaller radius into the direction of the incident ray, the reflected rays remaining within a reflection cone (18,19) having the same central axis as the reflector. Road markers according to claim 1, characterised in that the outer surface (15) of said reflectors (14) protrudes in hollowed parts of the outer surface of said projections (13), said hollowed parts being disposed on the side surface of said projections. Road markers according to claim 1, characterised in that said projections (13) are humps which are disposed transversally on said signal stripes (10). Road markers according to claim 1, characterised in that said projections (13) are hemispherical humps (22). Road markers according to claim 1, characterised in that two series of said projections (13) are disposed alternatively along said signal stripe (10), a first one of said two series being arranged perpendicularly to the the direction of said signal stripe (10) and a second one of said two series being arranged at an angle to said direction of said signal stripe (10). Road markers according to claim 1, characterised in that said projections (13,22) including said reflectors (14) are glued to said signal stripes (10).

Inventors: PACINI LIO, PACINI, LIO
Applicants: ITALVERNICI S R L, ITALVERNICI S.R.L.
Application year: 1990
Main classification: E01F9
IPC codes: E01F9