Method and device for illuminating the entrance portions of tunnels, particularly of tunnels in highways and motorways

Abstract: The object of the invention is a method of illuminating the entrance portions of tunnels, particularly of tunnels in highways and motorways. According to this method, the portion at the entrance (I) of tunnel (G) is illuminated over a length (L) which is sufficient for a driver's eyes to become accomodated to the conditions of a lesser degree of light in a tunnel at a predetermined, maximum running speed of vehicles, by having the light outside tunnel (G) suitably reflected toward the entrance (I) and into the interior of tunnel (G). The invention also provides a device for carrying out the said method, comprising a reflecting element (2) which is arranged at a distance from, and upstream of the entrance (I) of tunnel (G), relative to the vehicles running direction (V), and has its reflecting surface (3) turned toward the entrance (I).

Description: This invention concerns a method of illuminating the entrance portions of tunnels in highways and motorways, in which a portion at the entrance of the tunnel is illuminated with reflected external light over a length that is sufficient for the driver's eyes to become accomodated to the conditions of a lesser degree of light in a tunnel at a predetermined maximum running speed of vehicles, according to the preamble of claim 1. A method of this kind is known from the document DE-A-3408649. According to this document, the external light is allowed to enter the tunnel directly through openings provided in the tunnel's ceiling. Document DE-A-2334951 discloses a method of illuminating the interior of a tunnel with external light which enters the tunnel on both sides by passing through inclined wells and being reflected by suitable mirrors. The object of the invention is to provide a method as described in the preamble of claim 1 and which can be easily carried out and avoids the dazzlement of the driver's eyes. The method according to the invention is characterized in that the external light is reflected into the interior of the tunnel through the tunnel's entrance in the same sense as the vehicles entering the tunnel, and is directed downwardly to the roadway at the internal length which is consecutive to the entrance of the tunnel. The invention also concerns an arrangement for carrying out the method according to claim 1. This arrangement corresponds to the one known from the document DE-A-2334951 and comprises the features that the reflecting element is a panel supported at a sufficiently high level over the roadway by a bridge framework and provided with a curved, particularly concave, reflecting surface, which is formed by mirror elements and is turned toward the entrance of the tunnel in the running direction of the vehicles. The use of the method and the device according to the invention has the advantage that the external reflected light which enters the tunnel through the tunnel's entrance and is turned in the sense of the vehicle transit, strikes upon the vehicles from behind so that any risk of the drivers' eyes to be dazzled, is avoided. The size of a reflecting element can be suitably determined so as to provide such an illumination in a tunnel that is sufficient for eliminating the sudden falling of light in the tunnel entrance and for preventing the vehicles transiting through the tunnel in the contrary direction, from being frontally illuminated, which would dazzle the drivers'eyes. Other features further improving the above-disclosed method and device also form the object of the invention, and are the subject of the dependant claims. The particular features of the invention, and the advantages arising therefrom, will appear more in detail from the specification of one preferred embodiment thereof, which is shown by way of a non-limiting example in the accompanying drawings, in which: Figure 1 is a side view showing the arrangement according to the invention arranged in front of, and at a distance from the entrance of a tunnel. Figure 2 is a top plan view of the arrangement according to Figure 1. Referring to the Figures, an arrangement according to the invention for illuminating, particularly during day-time, the entrance portions of tunnels comprises a bridge framework 1 of any suitable type, which at its top portion carries a reflecting element 2 in form of a panel that is placed at such a sufficiently high level as to allow the transit of vehicles thereunder. The reflecting element 2 has its reflecting surface 3 turned toward the entrance I of tunnel G, and this reflecting surface is so turned that the incident external light E falling thereupon, is reflected as shown by reference letter R, into the interior of the tunnel entrance I, and on the roadway at the tunnel entrance inward portion. The reflecting panel 2 is so arranged and orientated that the reflected light R is set at an angle that allows the reflected light to penetrate for a length L through and into the tunnel entrance. The longitudinal extent of this length is such that at a predetermined maximum speed of vehicles transiting through a tunnel, it is sufficient for assuring a gradual accomodation of the drivers' eyes to the conditions of a lesser degree of light in the tunnel, so that the "dark orifice" effect is eliminated. The framework 1 may be of a trellis or tubular construction, and on its front side which is turned toward the incoming vehicles, as indicated by arrow V, it may also carry signaling elements, such as a signaling panel. The reflecting element 2 or its reflecting surface 3 may be formed by the rear side of the not shown signaling panel, which is opposite to the tunnel entrance, or the same may be supported on the said rear side of this panel. The reflecting element 2 is arranged at a distance D upstream of the entrance I of tunnel G. The reflecting surface 3 may be of any suitable type, and it may consist of mirror elements that can be differently composed, or of metal panels having a high coefficient of reflection. The reflecting panel 2 may be carried in a shiftable and orientatable manner owing to the provision of actuating means for causing it to swing in the horizontal and vertical direction, and of actuating means for causing it to slide in the transversal or vertical direction (both not shown). The actuating means can be automatically controlled by means of a control unit, such as a training unit, according to brightness sensors, and these means permit to still have optimum features of illumination even with the external light being set at a different angle, and having a different intensity, such as according to the varying position of the sun The reflecting surface 3 is so orientated and arranged that no reflection of light is produced in the contrary direction to the vehicles running direction V, so that any risk of the drivers' eyes to be dazzled, is efficaciously avoided. Moreover, the reflecting surface 3 may be made in form of a flat, entirely or locally curved, for example concave, surface. This surface may also consist of a plurality of individually curved modules. It is also possible to make the reflecting surface 3 with an angle of curvature which may be varied in one or in two dimensions. In order to efficaciously eliminate any loss in the reflection efficiency, resulting from the reflecting surface 3 being soiled, this surface may be treated with a matter that prevents the adhesion of dirt thereto. It is also possibile to have cleaning means of the manually operated, or servo-control operated, or automatic type, associated with the reflecting panel 2 for cleaning its reflecting surface.

Claims: Method of illuminating the entrance portions of tunnels, particularly of tunnels in highways and motorways, in which a portion at the entrance (I) of the tunnel (G) is illuminated with reflected external light over a length (L) that is sufficient for the driver's eyes to become accustomed to the conditions of a lesser degree of light in a tunnel at a predetermined maximum running speed of vehicles, characterized in that the external light is reflected into the interior of the tunnel (G) through the tunnel's entrance (I) in the same sense as the transit (V) of the vehicles entering the tunnel (G), and is directed downwardly to the roadway over the internal length (L) of to the entrance (I) of the tunnel (G). Method according to claim 1, characterized in that simultaneously with such an external light reflection, the external light may be condensed into a beam of a higher light density. Method according to claim 1 or 2, characterized in that as external light the natural ambient light from the sun is used. Method according to any of the preceding claims, characterized in that the reflected light is so directed that any dazzlement is avoided of vehicles transiting in a direction which is concordant with, or is contrary to the direction of reflection. An arrangement for carrying out the method according to claim 1, comprising at least one reflecting element (2) arranged outside the tunnel (G) and oriented so as to reflect external light into the interior of the tunnel (G), whereby the reflecting element (2) is a panel supported at a sufficiently high level over the roadway as to allow the transit of vehicles there under by a bridge framework (1) and provided with a curved, particularly concave, reflecting surface (3), which is formed by mirror elements and is turned toward the entrance (I) of the tunnel (G) in the running direction (V) of the vehicles. An arrangement according to claim 5, characterized in that the curvature of the reflecting surface (3) is adjustable. An arrangement according to claim 5, characterized in that the reflecting element (2) is supported so as to be swingable around at least one vertical axis and at least one horizontal axis, so as to be horizontally and vertically shiftable by hand-operated or servo-control operated or preferably automatic actuating means. An arrangement according to any of the claims 5-7, characterized in that the reflecting element (2) forms the rear side of a signaling element having its front side turned toward the incoming vehicles. An arrangement according to any of the claims 5-8, characterized in that hand-operated or automatic cleaning means are associated with the reflecting surface (3) of the reflecting element (2).

Inventors: BARLOCCO EMILIO, BARLOCCO, EMILIO
Applicants: DIACON SRL, DIACON S.R.L.
Application year: 1993
Main classification: F21S11
IPC codes: F21V7, F21S11