More specifically, this invention refers to a safety barrier with a structure that allows it to be rapidly retracted to allow the transit of vehicles from one lane to another during road and/or motorway maintenance work.

BACKGROUND ART The use of mobile barriers in lane dividing sections in order to guarantee opening for the passage of vehicles is known.

These barriers can consist of sections sliding on supports that can be fixed in appropriate housings in the ground. The overall longitudinal extension of the sliding sections can be up to 16 metres, with the supports, aligned as much as possible, positioned at a distance of around 1.5 metres apart. Their opening foresees the sliding of the sections to open a central gap followed by the temporary removal of around 20 supports from their respective housings and their loading on a motor vehicle for transport to a place relatively far away from the mobile barrier so that road maintenance work can be carried out in the vicinity of the barrier.

To date, mobile barriers consisting of cables stretched from one end to another of a gap and sustained by appropriate supports are also used. There must be at least three cables and the tension must be adequate to counter any impact and ensure safety. To open the gap, each cable must be loosened so that it can be released from the supports. The cables must then be rolled up into reels with an overall weight that exceeds 100 kg and loaded, by means of a crane, onto a motor vehicle which carries them away

from the opened gap.

A further type of mobile barrier consists of impact- resistant rigid plastic containers filled with antifreeze liquid, connected to each other by means of steel bars.

These bars must be reciprocally constrained in order to form a compact framework resistant to impact and at the same time presenting appropriate deformability to absorb any impact. To ensure this traction must also be applied to the steel barriers by connecting them to appropriate tighteners positioned at the longitudinal extremities of the gap. To open this mobile barrier, the containers must be emptied and the tension of the bars must be reduced. The steel bars must then be separated and the containers, which may be around 15 in number, each with an approximate volume of one cubic metre, must be loaded onto a motor vehicle and carried away.

One drawback is represented by the fact that the opening of each of the previously described mobile barriers requires the closure of at least one road lane immediately adjacent to the barrier itself.

Another drawback is represented by the fact that the opening of these barriers requires the intervention of appropriately trained and equipped workers as well as means of transport such as cranes and/or trucks which are sometimes very large.

A further drawback is represented by the fact that the operations to remove the mobile barriers in order to open the gap take around three hours to carry out, and during this period the vehicles in transit on the motorway or highway concerned are subjected to temporary halts or considerable slowing down to allow the work to be done.

DESCRIPTION OF THE INVENTION The aim of this invention is to provide a road safety barrier which automatically retracts to obtain central

connecting gaps between road and/or motorway lanes, capable of eliminating or significantly reducing the drawbacks described above.

This invention also aims to provide an automatically retractable road safety barrier that can be fitted to any gap requiring the minimum amount of space due solely to its actual presence in the working position.

This is achieved by means of a road safety barrier which automatically retracts to obtain central connecting gaps between road and/or motorway lanes, with the features described in the main claim.

The dependent claims describe advantageous embodiments of the invention.

The road safety barrier, which automatically retracts to obtain central connecting gaps between road and/or motorway lanes, as per this invention comprises: -a framework erected in working position that can be retracted to a rest position, consisting of reciprocally hinged elements; -a chamber, cut out from below a road surface, to house the said framework in the rest position; -means of support and of temporary blocking of the framework in the erect or working position; -means for the movement of the said framework from the working position to the rest position and vice versa; -a source of motion kinematically connected to said means of movement and equipped with appropriate means of control.

According to the invention the framework, in the rest position, retracted and contained inside the chamber, fills the chamber with its upper part flush with the road surface in order to ensure continuity with the surface.

The framework comprises mutually cooperating

reinforcement elements, in particular when the barrier is completely contained in the respective chamber, in order to ensure adequate mechanical resistance to the loads of the vehicles passing through the gap without undergoing appreciable deformation.

The surface of the framework can be treated with anticorrosion agents, for example it can be galvanised, and the part which is on view in the rest position can have a high degree of surface roughness in order to prevent slipping of the tyres of the vehicles passing over it.

To prevent the accidental fall of foreign bodies inside the chamber, when the framework is in the erect working position, the retractable barrier is fitted with a grid over the access to the chamber.

The chamber is appropriately dimensioned to contain not only the framework but also any small grained impurities that may fall through the grid. The base of the chamber is also equipped with drainage channels for the disposal of groundwater.

The means of support of the framework can be equipped with appropriately tensioned cables and means of elastic loading to absorb and support any vehicle impact.

DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will become evident on reading the following description of one embodiment of the invention, given as a non-binding example, with the help of the enclosed drawings, in which: -figure 1 shows a cross-section side view of a road barrier according to the invention, in the working position, with the central part excluded; -figure 2 shows an enlarged front view of the barrier in figure 1; -figure 3 shows a similar view that of to figure 1, with the barrier in the rest position; and

-figure 4 shows a similar view to that of figure 2, with the barrier in the rest position.

DESCRIPTION OF ONE EMBODIMENT In the figures, the reference number 10 generally indicates a road safety barrier, in the case in question a barrier that automatically retracts to obtain central connecting gaps between road and/or motorway lanes.

The barrier 10 comprises a framework 11 consisting of at least one crosspiece or rail 12 hinged at its ends to uprights or bars 13 each of which is hinged at the opposite end to the ground 14.

The central part of each upright 13 is fitted with a pin 15 designed to act as a hinged means of support for a pair of sections 16 positioned at right angles with respect to the uprights 13. Each section 16, extending longitudinally for a good part of the barrier 10, presents a central body 17 (figure 2) which is attached to the pins 15 and which supports a bar 18 designed to act as a guard- rail.

The means of restraint to the ground 14 for each upright 13 may consist of a fork-shaped coupling 19 with a reinforcement 20 buried in a concrete casting.

The fork-shaped coupling 19 is fitted with holes in which a pin 22 is inserted and which also goes through the relative hole 23 in the respective upright 13. A pair of tongues 24 is inserted between the fork-shaped coupling 19 and the respective upright 13 in order to stiffen the upright 13 in the erect position.

Each coupling 19 is fixed to the base of a chamber 25 designed to house the framework 11 retracted in the rest position (figure 3). The chamber 25 presents an access opening 26, immediately below the framework 11, covered by a special closing grid 27 fixed to the uprights 13. In the working position, the grid 27 is flush with the road

surface (figure 2), while in the rest position it is housed on the bottom of the chamber 25. The grid 27 may consist of a 25 millimetre mesh and may be covered by strips of rubber (not shown in the drawings) larger than those of the opening 26 in order to prevent snow from entering the chamber 25. The dimensions of the bottom of the chamber 25 may in any case be sufficient to contain not only the framework 11 in the rest position, but also any small sized particles that may fall in through the meshes of the grid 27. The bottom of the chamber 25 may also be equipped with drainage channels for the disposal of groundwater.

One longitudinal end of the rail 12 is hinged to the shaft 28 protruding from a respective linear actuator 29.

On the same longitudinal band, the section 16 also presents its end hinged to a shaft 30 of a respective linear actuator 31. The cylinders of each linear actuator 29 and 31 are hinged to a fixed frame 32 which is also designed to support a control device 33 to govern the movement of the retractable barrier 10.

The control device 33 can consist of a hydraulic distributor designed to receive pressurised oil from a machine tool receiving energy from any appropriate source (not shown in the drawings).

The control device 33 is hydraulically connected to any of the linear actuators 29 and 31 which, receiving pressurised oil, permit the protrusion of the respective shafts 28 and ° The control device 33 is fitted with a protruding lever 34 which is easily accessible from the outside so that it can be activated by an operator to control the lowering and/or raising of the retractable barrier 10.

Both the rail 12 and the section 16, at their longitudinal end opposite to the end fixed respectively to the shafts 28 and 30, are fixed to steel cables 35 the

other ends of which are attached to a fixed frame 36.

Each cable 35 is fitted with an adjustable tightener and a spring 37 close to the frame 36. The tightener may consist of a screw 38 fixed to the cable 35 close to the spring 37. An appropriate support is foreseen in correspondence with the central portion of each cable 35 and which may consist of a strip 39 hinged to an arm 40 integral with the cross-piece 12, said strip presenting holes to contain each cable 35.

The control device 33 can receive pressurised oil from an appropriate hand pump.

According to an embodiment not shown in the drawings, the retractable barrier can be moved by mechanical energy devices such as, for example, elastic loading means.

The retraction of the barrier 10 takes place according to the phases described below.

By turning the lever 34 on the control device 33 the source of energy is activated for the protrusion of the shafts 28 and 30 by the respective actuators 29 and 31. The source of energy may consist of a hydraulic accumulator or of elastic loading means.

The movement of the shafts 28 and 30 leads to a first inclination of the uprights 13 which, having overcome the resistance of the tongues 24, rotate further towards the ground 14 by gravitational effect. This phase foresees the use of hydraulic or spring brakes designed to control the protrusion of the shafts 28 and 30. This phase of lowering of the framework also foresees the possibility of temporary blocking by turning the lever 34.

The rotation concludes when the entire framework 11 is positioned inside the chamber 25 (figures 3 and 4).

The framework 11, in the rest position, retracted and contained within the chamber 25, fills the said chamber 25 presenting its upper portion, comprising the upper surface

12a of the rail 12 and the upper surfaces 18a of the bars 18, flush with the road surface in order to ensure continuity with this surface.

In cases of emergency it is possible to press the retractable barrier 10 towards the ground 14 by turning the lever 34 and operating the hand pump at the same time.

To return the framework 11 from the rest position inside the chamber 25 to the working position, it is necessary to operate the hand pump so that the shafts 28 and 30 retract inside the respective cylinders of the actuators 29 and 31, pulling the barrier 10 into the erect position. Continuing to operate the hand pump tightens the cables 35 and recharges the hydraulic accumulator or the elastic charging means thus restoring energy for subsequent opening of the barrier 10.

During the raising phase of the framework 11 the strip 39 prevents the cables 35 from becoming entangled or caught up giving rise to damage or unwanted blocking of the opening maneuver of the retractable barrier 10.

The framework 11 can be surface treated with anticorrosion agents, for example it can be galvanised, and the part which is on view in the rest position can have a high degree of surface roughness in order to prevent slipping of the tyres of the vehicles passing over it when the barrier 10 is housed inside the chamber 25.