Description

A Structured Element for Horizontal and/or Lateral Road Signals

Technical Field

Horizontal road signs commonly used on roads comprise signs or signals which are arranged on the asphalt to inform motorists of the margins of a lane or road, the presence of a stop signal or a signal instructing a motorist to give right of way, a compulsory direction or a notice, or some other purpose. Background Art

A horizontal signal is basically constituted by a representation of the signal traced on the asphalt using a paint having slight back-reflecting properties and/or refraction properties. These paints exhibit a very poor luminosity; in particular they are absolutely inadequate in the presence of fog or heavy rain. A further drawback of known-type horizontal signals, which leads to frequent repainting operations, is that they have a short working life as well as being poorly reflective.

In an attempt to offer at least a partial solution to the poor back-reflecting properties of painted signals, small inserts have been provided, which are sunk into the asphalt such as to project partially above the road surface. These inserts exhibit at least a front surface, facing towards the advancement direction of the vehicles, which has good back-reflecting characteristics. These inserts, however, are somewhat expensive, so much so that they are rarely used.

Concerning lateral signals, and in particular a vehicle weight indication, international regulation ECE/ONU 104, for vehicles exceeding certain masses and dimensions, provides for the application of back-reflecting panels in order to signal the presence and mass of the vehicle to the other road users when the light is poor. In particular lorries, road trains and articulated trucks are obliged to have a back-reflecting identification around the external edges thereof, in effect a rectangular frame which runs along all of the edges of the rear surfaces of the vehicle. In actual practice, many of these vehicles bear the bands on all of the lateral surfaces thereof too. Known-type strips or bands superficially exhibit a flat plane of back- reflecting material, provided with light-reflecting properties, preferably in the direction of the incident rays reflected directionally (the back-reflecting or refraction effect). The beam of light issuing from the front lights of other vehicles is therefore reflected by the back-reflecting elements, substantially back in the same direction as the light source that emitted the beam, i.e. towards the driver of the following vehicle. In conditions of poor visibility, the light reflected towards the driver enables the driver to identify the vehicle provided with the back-reflecting profiles, as well as to determine the size of the vehicle accurately. The back-reflecting ability of the materials used is not constant for all incident rays. If we define the angle of illumination as the angle comprised between the beam of incident light and the perpendicular to a surface of back- reflecting material, we observe that after a certain angle the back-reflecting effect is annulled. The maximum angular value of the angle of illumination, without annulling the back-reflecting effect, is commonly known as the angularity of the material.

Research in the field of back-reflecting materials has led to the development of materials having high angularity qualities, but there are still limits to the effectiveness of the back-reflecting edging. In some relative positions between the illuminating vehicle and the reflected strips on the preceding vehicle (for example when the two vehicles are in different lanes), the angularity is reached and exceeded by the beam angles coming from the light sources of the illuminating vehicle. In practical terms this means that in low- visibility conditions the reflection obtained is not sufficient to signal the size of the vehicle bearing the strips to the driver of the other vehicle. The aim of the present invention is to illustrate a structured element for horizontal and/or lateral signalling elements which enables well-visible horizontal and/or lateral signals to be realised, even in conditions of poor visibility (rain and/or snow, poor light); the signals are furthermore economical to produce and easily associable to the road surface; they also offer greater resistance and have a longer working lift than the paint normally used for realising horizontal signals.

A further aim of the present invention is to provide a back-reflecting strip for signalling a size of a vehicle which maintains its back-reflecting properties even when illuminated by a light beam orientated at a very high angle of incidence.

An advantage of the invention is that the illustrated strip is simple and economical. The strip is further effective for posteriorly indicating the transversal and elevation sizes of a vehicle, as well as for laterally indicating the length and height of a vehicle. Disclosure of Invention

Further characteristics and advantages of the invention will better emerge from the detailed description that follows, made with reference to the

accompanying pictures of the drawings, given purely by way of non-limiting example, in which: figure 1 is a schematic perspective view of a structured element of the present invention; figure 2 is a front view of the structured element of figure 1 ; figure 3 is an example of use of the structured element of the present invention for realising the demarcation lines of the lanes of a one-way street; figure 4 is an example of use of the structured element of the present invention for realising the demarcation lines of the lanes of a two-way street; figure 5 is a plan view of a first embodiment of the structured element of the present invention; figure 6 is a plan view of a second embodiment of the structured element of the present invention; figure 7 is a front view of a structured element made as in the embodiment of figure 5; figure 8 is a perspective view of the structured element of figure 7, in a further embodiment; figure 9 is a schematic view of how a light cone projected from the headlight of a motor vehicle strikes the back-reflecting element associated to the lateral surface of a lorry; figure 10 illustrates a back-reflecting element of the present invention associated to the back surface of a lorry.

With reference to the figures of the drawings, the structured element 1 of the present invention can be used both for horizontal signals and for lateral signals, or to signal the presence of structures projecting upwards from the sides of the road surface. These structures comprise guard rails, New Jersey barriers, poles or even trees which are in the immediate vicinity of a road.

The structured element 1 comprises a support layer 2, provided with a longitudinal axis x which extends along a lie plane SG. A back-reflecting layer 3 is associated to the support layer 2.

The back-reflecting layer 3 is preferably made of a micro-prism structure. The connection of the back-reflecting layer 3 to the support layer 2 is obtainable by means of a gluing process using a self-polymerising solvent- free polyurethane resin. The support layer 2 is first spread with a layer of primer on which a solvent-free polyurethane resin is spread. The back- reflecting layer 3 is then spread on the solvent-free polyurethane resin layer. When the polyurethane resin completes polymerisation the support layer 2 is solidly constrained to the back-reflecting layer 3.

The structured element 1 further comprises a plurality of parallel reliefs 4 which project from the lie plane SG of the part in which the back-reflecting layer 3 is located. Each of the reliefs is orientated in a direction y which is inclined with respect to the longitudinal axis x. Preferably, especially in the case in. which the structured element is to be used to make a horizontal sign, the orientation direction y is diagonal with respect to the longitudinal axis x and the angle α formed by the longitudinal axis x and the orientation y of the reliefs is approximately comprised between 30° and 50°, as can be seen in figure 6. If the structured element is for realising a lateral signal, the angle α formed by the longitudinal axis x and the orientation y of the reliefs is approximately 90°, as can be seen in figure 5.

Each relief 4 exhibits, in transversal section, a trapezoid profile, which is open at the larger base and which is provided with two lateral surfaces 4a, 4b which extend from the lie surface SG and converge towards one another, being joined by a top surface 4c. Ideally a base portion PB of the lie plane SG closes the trapezoid profile. The lateral surfaces, together with the portion of

back-reflecting layer associated thereto, are therefore arranged transversally with respect to the lie plane SG such that at least one of them, for example a first 4a of the lateral surfaces, is facing towards the direction in which the vehicle is coming. With reference to a transversal section of the structured element 1, each relief preferably exhibits a height of about 6mm. The maximum width (or the maximum distance separating the lateral surfaces 4a, 4b) is about 10mm, while the projections of the lateral surfaces 4a, 4b on the base portions PB are about 3mm. The reliefs 4 are preferably alternated with smaller reliefs 41 which are parallel thereto. The smaller reliefs face in directions y which are parallel to the orientation directions of the reliefs 4.

Each of the smaller reliefs 41, similarly to the reliefs 4, exhibits, in transversal section, a trapezoid profile, open at the larger base, which is provided with two lateral surfaces 41a, 41b which extend from the lie surface SG and converge, being joined by a top surface 41c. A base portion PB of the . lie plane SG ideally closes the trapezoid profile. The lateral surfaces, together with the portions of back-reflecting layer associated thereto, are arranged transversally with respect to the lie plane SG such that at least one of them, for example a first 41a of the lateral sides, is facing towards the direction in which the vehicle is coming. Each relief is preferably about 3mm high. The maximum width (or the maximum distance separating the lateral surfaces 41a, 41b) is about 5mm. To realise a horizontal signal, for example a lateral strip delimiting a lane as shown in figures 3 and 4, a structured element .1 is shaped as a strip with a longitudinal axis x going in a parallel direction to the direction of development of the road or lane. The diagonal inclination of the reliefs 4 is

such that the vertex of the angle formed between the longitudinal axis x and the direction of orientation y of the reliefs 4 is facing in the advancement direction DM of the vehicle.

As schematically represented in figures 3 and 4, the most lateral fractions of the light beams projected by the headlights of a motor vehicle are divergent with respect to the advancement direction of the vehicle itself. The diagonal direction y of orientation of the reliefs 4 means that the lateral fractions projected by the headlights, which are deputed to illuminating the spaces lateral of the vehicle, invest the structured elements 1 with an angle of incidence which is very small with respect to the first lateral surface 4a of the reliefs 4. Thanks to this advantageous arrangement of the reliefs 4, the lateral fractions of the light beams projected by the lights are back-reflected towards the vehicle, indicating with very good luminosity the presence of a horizontal signal arranged laterally with respect to the road. From a constructional point of view, the structured element 1 comprises a filler layer 5 associated to the support layer 2 .on. the opposite side with respect to the back-reflecting layer 3. The filler layer 5 fills the recesses 6 present in the support layer 3 on the opposite side to the reliefs 4. The filler layer 5 establishes and increases the resistance of the reliefs 4 to the crushing forces they are subject to by effect of the passage of motor vehicles. The filler layer 5 preferably comprises corundum powder which has the function of increasing the roughness of the filler layer 5 itself.

In a preferred embodiment of the structured element 1, the filler layer 5 is made of polyurethane resin internally of which the corundum powder is suspended. The presence of the corundum powder, which as mentioned increases the roughness of the filler layer 5, leads to a considerable increase in the friction coefficient between the structured element 1 and the road

surface. In this way, the structured element 1, once constrained to the road surface, keeps its position stably. The connection between the element 1 and the road surface can be effected by gluing or by riveting, or in another way. The presence of the corundum powders offers a further important advantage: when a structured element 1 wears or is damaged, and in particular in the case where the reflecting layer and the support layer tear, uncovering the filler layer 5, there remains the certainty that vehicle tyres have excellent adherence thanks to the effect of the roughness of the filler layer. The adherence of the tyres to the back-reflecting layer 3 is considerably increased by the application of a coat of anti-skid paint, comprising rubber or corundum, spread on the back-reflecting layer 3, in particular on the top surface of the reliefs. The polyurethane resin can advantageously be coloured so that should the support layer 2 and the reflecting layer 3 tear, a coloured part is exposed which is preferably the same colour as the back-reflecting layer. To increase the resistance of the structured element 1 support layer 2 is longitudinally folded along the edges thereof in order to define two folds 2a, 2b, illustrated in figure- 1, which at least partially superpose the back- reflecting layer 3. This also increases the stability and duration of the connection between the back-reflecting layer 3 and the support layer 2 inasmuch as possible detachments of the back-reflecting layer 3 along the edges thereof. As a further reinforcement for the structured element 1, at the end portions of the structured element 1 there can be two reinforcement elements 2c, 2d having a C-shaped section which press the support layer 2 and the back-reflecting layer 3 towards each other in order to prevent any detachments between the two layers at the end portions of the structured element 1. The two reinforcement elements 2c, 2d could also be constituted by two end folds of the support element 2 folded onto one another,

superposing on the back-reflecting layer 3. The reinforcement elements 2c, 2d can be provided with holes for connection to a support surface. The support layer 2 is preferably made of soft aluminium. This material offers a relatively high degree of resistance in combination with high malleability. In particular, owing to its malleability, even in a case of fracture with formation of projecting edges, the soft aluminium tends to be crushed by effect of the pressure exerted by the tyres, reducing the risk of damage to the tyres themselves. The structured element of the present invention can be made in the following way.

Following catalysis of the resin layer connecting the support layer 2 and the back-reflecting layer 3, a layer of primer is spread on the support layer 2. A first layer of solvent-free self-polymerising polyurethane resin is spread on the primer. A layer of textile material, for example glass fibre or nylon or the like, is then arranged on the polyurethane resin, which partly sinks into the first layer of polyurethane resin. . _ . . . . _ .

The reliefs 4, 41 can for example be impressed by deformation on the support layer 2. Following the polymerisation of the first layer of polyurethane resin, the reliefs can be impressed on the support layer 2 by running the support layer 2 together with the back-reflecting layer 3, between a pair of cylinders. A first of these cylinder bears (in relief) the projecting shape of the reliefs, while the other cylinder affords a series of recesses which negatively reproduce the shape of the reliefs. The two cylinders roll without dragging on each other and are arranged with an interaxis which is such that in the zone of minimum distanced between the surfaces of the two rollers, at which the support layer 2 and the back-reflecting layer 3 transit, each positive relief is at least partially arranged internally of a corresponding recess.

When the reliefs 4, 41 have been made, the filler layer 5, described herein above, is spread, to which the corundum powder is added. A further layer of textile material can be stretched on the filler layer 5, which textile at least partially sinks into the filler layer 5. More corundum powder can then be spread in the filler layer 5. The textile layers have the function of increasing the resistance and stability of the filler layer 5 and increasing the solidity of the anchoring of the filler layer 5 to the support layer 2. With particular reference to realising lateral signals, and signals indicating the dimensions of a vehicle, illustrated in figures from 7 to 10, the back-reflecting element of the present invention comprises at least a structured element 1, comprising in turn a support layer 2 to which a back-reflecting layer 3 is associated. The support layer 2 develops overall in a lie plane SG and is shaped such as to define a plurality of longitudinal reliefs 4 which project from the lie plane SG. The longitudinal axes y of the reliefs are parallel. The back-reflecting layer 3 is associated to one of the surfaces of the support layer 2 in order to follow the reliefs 4.

The reliefs 4 are preferably prismatic and exhibit a first and a second lateral surface 4a, 4b, which project transversally with respect to the lie plane SG and are inclined by a determined angle γ with respect thereto. The reliefs 4 preferably have a triangular or trapezoid section.

With reference to a transversal section of the structured element 1, each relief preferably exhibits a height of 6mm. The maximum width (i.e. the maximum distance separating the lateral surfaces 4a, 4b) is about 10mm, while the projections of the lateral surfaces 4a, 4b on the lie plane SG are about 3 mm. The minimum distance separating two consecutive reliefs 4 is about double the maximum width of each relief, i.e. is about 20 mm. This prevents a relief 4 from projecting its shadow on another relief.

The structured element 1 is predisposed to be associated to a surface of a vehicle such that the longitudinal axes y of the reliefs 4 lie on vertical planes. In this way the lateral surfaces 4a, 4b of the prismatic reliefs 4 are arranged transversally of the vehicle surface, projecting from the surface and being directed towards the opposite sides of the surface.

The reliefs 4 are preferably alternated with smaller reliefs 41 which are parallel to them. Each of the smaller reliefs 41, similarly to the reliefs 4, exhibits, in transversal section, a trapezoid profile, which is open at the larger base, which profile is provided with two lateral surfaces 41a, 41b which extend from the lie plane SG and converge towards one another, being joined by a top surface 41c. The lateral surfaces, together with the portions of back- reflecting layer 3 associated thereto, are arranged transversally with respect to the lie plane SG so that at least one of them is facing towards the advancing vehicle. Each relief preferably exhibits a height of about 3mm. The maximum width (i.e. the maximum distance separating the lateral surfaces 41a, 41b) is about 5mm. . _ .

Preferably, though not necessarily, the structured element 1 comprises a filler layer 5 associated to the support layer 2 on the opposite side with respect to the back-reflecting layer 3. The filler layer 5 fills the recesses 6 in the support layer 3 on the opposite side to the reliefs 4 and the smaller reliefs 41 if present. The filler layer 5 establishes and increases the resistance of the reliefs 4 and the smaller reliefs 41 if present, against the crushing forces. In a preferred embodiment of the structured element 1 the filler layer 5 is made of polyurethane resin. To make both the lateral signals or for signals indicating the dimensions of a vehicle, a flat layer 10, preferably made of soft aluminium, can be associated to the support layer 2 below the reliefs 4, so that it can be arranged on the lie

plane SG, with the aim of facilitating application of the structured element 1 to a surface. The flat layer 10 can be associated to the support layer 2 by means of a layer of self-polymerising adhesive, or mechanical connecting elements (for example screws or rivets). The presence of the flat layer 10 defines a flat rest surface for the structured element 1 which is particularly advantageous for connecting the structured element 1 to a surface by gluing. The effects and advantages deriving from the special conformation of the element are clearly illustrated in figure 9. This figure shows a plurality of vehicles nearing one another, along distinct directions, to the vehicle bearing the back-reflecting element according to the invention. The figure schematically illustrates the distribution of the light cones projected by the lights of the oncoming vehicles. As clearly illustrated in figure 1, whatever the approaching direction of the vehicle projecting the light, the angle of illumination of the light beams which are incident on the element is always below the material's angularity.

If the illuminated vehicle had flat back-reflecting strips of known type, the angle of illumination of the light beams striking the elements would be greater than the angularity of the reflecting material. Consequently, in conditions of poor visibility, the shape of the illuminated vehicle would be insufficiently conspicuous to the eyes of the driver of illuminating vehicle. The presence of the reliefs 4 and the lateral surfaces 4a, 4b of the reliefs themselves means that at least some portions of the back-reflecting layer 3, especially those portions associated to the lateral surfaces of the reliefs 4, are facing towards the light cone. The lateral portion 10 of the light cone strikes the lateral surfaces with angles of illumination β which are lower than the angularity of the back-reflecting material, such that the light is reflected there-from back towards the light beam, resulting in good illumination of the

element vis-a-vis the driver of the oncoming vehicle, and especially in conditions of night-time visibility.

Figure 9 illustrates a relative position of the vehicles in which the presence of the elements of the invention on the side surfaces of the illuminated vehicle are decisive for easy identification of the vehicle by another driver; it is easy to imagine how the relative positions of the vehicles in normal traffic conditions would improve the visibility of the element applied on the back surface of the illuminated vehicle. A first example might be one in which the illuminating vehicle is about to turn into a main road on a tract thereof just vacated by the other vehicle; here the illumination which the lights of the turning vehicle make on the illuminated vehicle is of high intensity. In a second example, illustrated in figure 9, a vehicle proceeding in an opposite direction to the lorry gains a good view of the illuminated outline of the lorry thanks to the presence of the element of the invention. Preferably, in order to gain a good impression not only of the presence but also of the dimensions of the vehicle the back-reflecting element is fixed on ₅ the element is configured in a rectangular frame-shape, predisposed to be applied along the edges of a surface of a vehicle. The application surface can be a lateral surface or a posterior surface. The structured elements 1 will therefore be positioned along the perimeter of the surface. The four structured elements 1 are elongate longitudinal strips. Two of them are applied along the lower and upper edge of the surface on which the signals are to be fixed; these exhibits reliefs 4 having longitudinal axes y which are perpendicular to the longitudinal extension direction of the strip. The other two strips, to be applied on the lateral edges, exhibit reliefs 4 having longitudinal axes y parallel to the longitudinal extension direction of the plates.

The structured element of the present invention can be made by the following process.

Following catalysis of the resin layer connecting the support layer 2 and the back-reflecting layer 3, a layer of primer is spread on the opposite side of the support layer 2. Thereafter a first coat of solvent-free self-polymerising polyurethane resin is spread on the layer of primer. A layer of a textile material is spread on the layer of polyurethane resin, for example glass fibre or nylon or another material, which at least partially sinks into the first layer of polyurethane resin. The reliefs 4, 41 can for example be made by deformation of the support layer 2. Following the polymerisation of the first layer of polyurethane resin, the reliefs can be impressed on the support layer 2 by running the support layer, with the back-reflecting layer attached, between a pair of cylinders. A first of these cylinder bears (in relief) the projecting shape of the reliefs, while the other cylinder affords a series of recesses which negatively reproduce the shape of the reliefs. The two cylinders roll without dragging on each other and are arranged with an interaxis which is such that in the zone of minimum distance between the surfaces of the two rollers, through which the support layer 2 and the back-reflecting layer 3 transit, each positive relief is at least partially arranged internally of a corresponding recess.

When the reliefs 4, 41 have been made, the filler layer 5, described herein above, is spread, to which the corundum powder is added. A further layer of textile material can be stretched on the filler layer 5, which textile at least partially sinks into the filler layer 5. More corundum powder can then be spread in the filler layer 5. The textile layers have the function of increasing the resistance and stability of the filler layer 5 and increasing the solidity of the anchoring of the filler layer 5 to the support layer 2.

The structured element of the present invention attains all the set aims. It enables horizontal signals and/or lateral signals to be made which are very clearly apparent, even in conditions of poor visibility. The costs involved are contained, including from the point of view of the application of the elements on the road surface. The structured element is also very much more resistant and long-wearing than the paints which are commonly used for making horizontal signals.