The present invention is relative to an automatic barrier, adapted to close and open an access. During the above-mentioned opening and closing procedures, said barrier is able to detect the presence of an obstacle close to the barrier itself, thus preventing objects or people from damages to.

The movement of the barrier can be a rotation around one of its ends, which occurs, for example, in the type of barriers used in tollgates, or a translation along a horizontal or vertical axis, which occurs, for example, in those barriers associated to gates or rolling shutters.

Barriers are known, which comprise sensors adapted to stop the closing of the barrier itself. Said sensors normally are pressure sensors, which stop the closing of the barrier only in case of direct contact with an obstacle; though, other types of sensors currently available on the market can be used.

Said pressure sensor, for example, comprises a plurality of switches, which are properly connected to one another, so that the closing of said barrier is stopped due to the collision with an obstacle.

Said switches can also be activated by a soft element, which is arranged on the edge of the barrier and, when it is pressed, stretches a cable, which is arranged in its inside and is fixed, at one of its ends, to one of the above-mentioned switches.

Indeed, the closing/opening of at least one of said switches is sufficient to stop the closing of the barrier. If the obstacle touches a portion of the barrier where said sensor is not present, the movement of the barrier is not stopped, thus causing serious damages to things or people, as well as to the barrier itself.

Resistive-type ribs for the detection obstacles are known, in which, inside the rubber rib itself, a wire is provided, which extends in parallel along the rib with a given electrical resistance, which is measured at its ends. When said lower edge hits an obstacle, the wire comes into contact with itself, thus varying the electrical resistance measured at its ends. Said resistance variation causes a control unit to stop the closing of the barrier.

Furthermore, pressure ribs for the detection of obstacles are known, in which, inside the rubber rib itself, a gas with a given pressure is provided. When the rib hits and obstacle, it deforms, thus causing a pressure increase, which is detected by the pressure switch, thus interrupting the closing of the barrier.

This type of barrier is normally used in the technical field of road barriers, such as the ones used in tollgates or in car parks where a charge has to be paid.

In case an obstacle is present in the field of action of this type of barrier, the closing movement of the barrier itself is stopped only when the latter hits said obstacle, thus causing damages. In this technical field the obstacle normally is a car.

Furthermore, in the motorway technical field, for example in tollgates, the use of barriers comprising contact sensors can cause damages to obljects or people, especially in those preferential fast lanes, where the payment is carried out when a recognition system recognizes the transponder associated to the vehicle. In case the vehicle is driving too fast or in case of faults of the recognition system, the vehicle can violently hit said barrier, thus causing serious damages to the vehicle and to the barrier itself.

On the other hand, in case the vehicle, for unspecified reasons, stops under the barrier after the latter has been raised to allow the passage of the vehicle itself, said barrier will hit the vehicle during the lowering process, since the contact sensor will stop the lowering of the barrier only when said barrier hits the vehicle. A problem that is even more difficult to solve is relative to the possibility to detect the presence of a person or a motorcycle under said barrier, since their size is much smaller.

A further problem, which is similar to the previous ones, concerns the barriers used to control the entrance and the exit of car parks where a charge has to be paid. Indeed, in some cases, for example in case of traffic jams, said barriers can hit vehicles and cars that stop under the barrier for a long time, thus causing damages to the car or vehicle involved.

The object of the present invention is to solve the above-mentioned technical problems by providing a barrier comprising sensors that are adapted to detect the presence of an obstacle, even an obstacle with a reduced size, for example during the movement of the barrier itself, preventing the barrier itself from hitting said obstacle, thus avoiding damages to objects or people.

One aspect of the present invention is relative to a mobile barrier having the features set forth in appended claim 1.

Further accessory features are set forth in the appended dependent claims. The additional features and advantages of barrier according to the present invention will be best understood upon perusal of the following detailed description of an embodiment with reference to the accompanying drawings, which respectively illustrate what follows:

• figure 1 shows a flowchart of the electric and electronic circuit of the mobile barrier according to the present invention;

• figure 2 shows an embodiment of the barrier according to the present invention;

• figure 3 shows, in detail, the flowchart of the sensors comprised in the barrier according to the present invention.

With reference to the figures mentioned above, the mobile barrier B comprises at least one bar A , at least one actuator 3, which is suited to move the bar A itself for example by mans of mechanical devices for the transmission of motion, a control unit 2, adapted to transmit a plurality of signals to said at least one actuator 3, so as to move said bar A , by means of at least one data line 22.

Said at least one bar A can be rigid or foldable by means of pliable means. The bar can rotate around a pivot, as shown in the appended figure, or, always within the scope of protection of the present invention, it can also be moved with a horizontal or vertical translation.

Said barrier B comprises at least one proximity sensor 4, which is arranged on said barrier B , is electrically connected to said control unit 2 , and is adapted to detect the presence of one or more obstacles 0 in proximity to barrier B . Said proximity sensor 4 preferably is an ultrasonic sensor comprising at least one transmitter 41 and at least one receiver 42, as shown in figure 3.

Said control unit 2 is adapted to acquire the information of said at least one sensor 4 and, in case an obstacle 0 is identified close the barrier B , to transmit a proper signal to said at least one actuator 3, so as to correctly move bar A .

Said data line 22 is adapted to establish a communication among said control unit 2, said at least one actuator 3 and said at least one sensor 4, so as to transfer data from one unit to the other.

Said barrier B comprises, furthermore, at least one power supply 5, adapted to supply power to all the electronic devices comprised in barrier B according to the present invention.

Said power supply 5 can be an AC/DC converter, if said barrier B is connected, for example, to the electricity network, or a voltage stabilizer, if said power supply 5 is connected, for example, to a solar panel or to another type of energy generator. Preferably, said control unit 2 is adapted to control the power supply to said at least one sensor 4, thus enabling or disabling the supply of power to said at least one sensor 4, for example by means of a switch.

Said at least one actuator 3 is, for example, an electric motor, preferably a single-phase electric motor, adapted, by means of proper transmission means, to lift and lower bar A comprised in barrier B with a predetermined speed, for example a speed established by control unit 2.

In an embodiment of the present invention, said transmitter 41 is a piezoelectric transducer, adapted to convert an electrical signal at a predetermined frequency into a mechanical wave. The frequency of the electrical signal is at least higher than 20MHz, so that the mechanical wave generated by said transducer is comprised in the ultrasounds.

For the purpose of the present invention, the term mechanical wave indicates a variation of the atmospheric pressure that propagates in the air at a given speed and with a predetermined attenuation.

Said mechanical wave propagates according to a proper radiation diagram as a function of the arrangement of said at least one transmitter 41.

Said receiver 42 is a transducer, adapted to convert the mechanical waves propagating in the air into an electrical signal. Said transducer is adapted to transform a sound wave, preferably comprised in the ultrasounds, into an electrical signal .

Said transmitter 41 and said receiver 42 are adjusted to one another, so as to work on the same frequency band and, preferably, using the same signal modulation.

The radiation diagrams of transmitter 41 and of receiver 42 are such that the direct wave transmitted by the transmitter is not directly received by receiver 42.

Using the principle of reflected waves, receiver 42 receives a signal only when the wave transmitted by transmitter 41 is reflected towards receiver 42, for example by an obstacle 0 .

Preferably, furthermore, said transmitter 41 and said receiver 42 are arranged close to one another, so that the wave reflected by the ground is external to the receiving diagram of he receiver 42. The distance, switching and range settings of the signal of different sensors 4 can vary as a function of the position in which said barrier B is applied.

Preferably, said sensors 4 are applied to the lower portion of bar A , more preferably on the edge, so that they can detect the presence of an obstacle 0 .

For the purpose of the present invention, the term lower portion of bar A indicates the portion of the bar that is the closest to the ground.

The number and the arrangement of sensors 4 vary as a function of the application and of the size of barrier B and, in particular, of bar A itself. As the length of bar A increases, the number of sensors 4 has to be increased as well, so as to cover at least the field of action of entire barrier B .

Said at least one sensor 4 is connected to data line 22 in the wired-or logic.

This connection allows a reduction of the energy consumption of the whole system.

Said data line preferably is a data bus, which carries the main decisional items of information.

At least two cables comprised in data line 22 itself are used to distribute the power supply from control unit 2 towards different sensors 4 available. Said data line 22 is preferably manufactured with a cable with three conductor wires having the following functions: a first GND wire used as voltage reference; a second Vcc wire for the supply of power, for example +5V; and a line for the transmission of data, in which data can travel from and to said control unit 2.

In predetermined operating conditions, said sensors are supplied with power; after sensors 4 have been supplied with power, transmitters 41 comprised therein start radiating said mechanical waves. Said sensors 4 are connected to data line 22, so that, in case one or more receivers 42 receive a mechanical wave reflected by an obstacle 0 , sensor 4 introduces a signal into data line 22, preferably a digital on/off signal, for example an impulse, which is accepted by control unit 2. Upon receiving the signal coming from one or more sensors 4, unit 2 transmits the proper control to actuator 3.

Preferably, control unit 2 monitors data line 22, so as to instantaneously detect a signal coming from one or more sensors 4.

In an alternative embodiment, said sensor is a Doppler effect sensor. In this embodiment, control unit 2 determines, as a function of the beat between the maximum frequency transmitted by transmitter 41 and the one received by receiver 42, whether an object, which is potentially adapted to hit or obstruct barrier B , is moving; based on this item of information, it accordingly acts on actuator 3.

Preferably, the activation logic of sensors 4 and their functional features, such as the reaction distance, can be set and adjusted during installation. In particular, the minimum distance at which an obstacle O is detected, with respect to barrier B where different sensors 4 are arranged, can be adjusted by varying, for example, the arrangement and the operating frequency of sensors 4 themselves .

Said control unit 2 comprises a process control unit, which is able to execute a code portion stored in a nonvolatile memory medium, adapted to handle mobile barrier B according to the present invention by performing the following subsequent operating steps:

a) control unit 2 receives a bar A lifting signal; b) sending an activation signal from said control unit 2 towards at least one actuator 3, so as to open barrier B ;

c) lifting bar A ;

d) said control unit 2 receives a barrier B closing signal ;

e) sending an activation signal from said control unit 2 towards at least one actuator 3, so as to close barrier B ;

f) lowering bar A ;

g) closing barrier B .

Subsequent to step e) and preferably simultaneously to step f) , the following further sub-steps are provided:

kl) activation of said at least one sensor 4;

k.2) monitoring of possible presence of obstacles O , by said at least one sensor 4;

k3) transmission of data from said at least one sensor

4 towards control unit 2.

During step a) for receiving a lifting signal, control unit 2 receives a bar A lifting signal, which is generated, for example, by the pressure exerted by an operator on a push-button or by a vehicle recognition device.

After control unit 2 has received said signal, step b) begins, during which an activation signal is sent, so as to open barrier B . Said activation signal comprises items of information such as, for example, the speed with which actuator 3 has to lift said bar A .

Subsequently, step c) begins, during which actuator 3 lifts bar A . After bar A has been lifted by actuator 3, step d) begins, during which said control unit 2 receives a barrier B closing signal. During this step, control unit 2 receives said closing signal, which is generated, for example by the pressure exerted by an operator on a push-button or by a presence sensor, such as a photodetector, or by a counter, after a predetermined amount of time has elapsed.

Subsequently, step e) beings, during which an activation signal is sent, so as to close barrier B .

After said signal has been received, step f) begins, during which bar A is lowered due to the action of actuator

3, which starts the downward movement of bar A at a predetermined speed.

Simultaneously to the begin of step f ) , step kl) for the activation of said at least one sensor 4 is performed, during which control unit 2 supplies power to said sensors

4, so as to perform step k2) , during which the possible presence of obstacles 0 is monitored. During said step k2) , transmitter 41 transmits a mechanical wave, which, in case of presence of an obstacle 0 close to barrier B , is reflected and received by receiver 42. Subsequently, step k3) begins, during which data are transmitted from said at least one sensor 4 towards control unit 2 by means of data line 22.

In case an obstacle O is detected, sensor 4 sends data to control unit 2, until, for example, obstacle O is out of the radiation diagram of sensor 4.

During this time span, control unit 4 sends, for example, a lowering stop signal to actuator 3. Upon receiving the lowering stop signal, actuator 3 is stopped and, if necessary, reverses the actuation signal, so as to lift bar A . Steps k2) and k3 ) are repeated in sequence as long as obstacle 0 remains close to barrier B , in particular in the radiation diagram of transmitter 41, and receiver 42 receives the wave reflected by said obstacle 0 . Once said obstacle O is no longer detected by sensors 4, the processing unit performs again step f) reaching final step g) ·

Preferably, in case no obstacle 0 is detected during said step f) and before the final step g) is completed, during which the barrier B is closed, steps k2) and k3 ) are repeated in sequence until step f) is completed, thus reaching the subsequent step g) , during which barrier B is closed .

In an alternative embodiment, in case an obstacle O is detected during step f ) , control unit 2, by means of suitable algorithms, can process the data coming from said sensors 4 determining the real position of obstacle O with respect to the field of action of bar A . These algorithms, as a function of which sensors arranged on the bar have perceived obstacle 0 and as a function of the intensity with which the reflected wave is received by receiver 42, determine the most suitable way to move bar A , so as to prevent objects or people from damages. In this embodiment control unit 2, in some cases, can slow down the lowering movement of bar A , so as to determine the exact position of obstacle 0 and to check if the latter has changed its position in time. In case the distance between obstacle 0 and barrier B is lower than a predetermined value, bar A is stopped and, if necessary, lifted by actuator 3.

In an alternative embodiment, steps kl) , k2) and k3) can also be performed after step c) and before the beginning of step e) . In case no obstacle 0 is detected after step c) and before step e) , control unit 2 does not send any activation signal to actuator 3 until said obstacle 0 is present in the monitored area, thus keeping the bar lifted.

Steps k2) and k3 ) are performed in sequence until said obstacle 0 is detected by sensor 4. Once said obstacle 0 is no longer detected by sensors 4, the processing unit performs step e) .

In an alternative embodiment, steps kl) , k2) and k3) can also be performed simultaneously step c) . In this embodiment, in which the sensors are Doppler effect sensors, the speed at which obstacle 0 , for example a vehicle, moves can be measured and, if said vehicle has a speed that is higher than a predetermined limit speed, control unit 2 sends a further activation signal for the opening of barrier B , in which the lifting speed with which bar A is lifted by actuator 3 is higher than the previous speed, so as to prevent the vehicle from hitting bar A being lifted.

Control unit 2, therefore, is adapted to process the data coming from sensors 4, so as to send the suitable activation/deactivation signals to actuator 3.

Said data coming from sensors 4 can be both digital signals and analogue signals, as a function of the technology with which sensor 4 is manufactured. For example, in case said sensors 4 are Doppler effect sensors, the data transferred to control unit 2 contain information both on the presence of an obstacle 0 and on the relative speed of obstacle 0 itself.

In the preferred embodiment, said sensors 4 are built- in in barrier B and are arranged so as to detect possible obstacles 0 at least in the field of action of barrier B itself. Preferably, said sensors 4 are arranged in the lower portion of bar A .

In an alternative embodiment, said sensors 4 are arranged on a support, which is preferably flexible and, in turn, is fixed to barrier B preferably in the lower portion of bar A .

The electrical features of data line 22 are electromagnetically compatible with the detection system made up of said sensors 4.

In order to manufacture said barrier B , proximity sensors can be used, which are implemented with different technologies The use of ultrasonic sensors causes the system to be free of electromagnetic interferences, which can affect the measurement.

Said control unit 2 is preferably housed in the control panel, which, for example, is arranged close to the handling booth, where actuator 3 is arranged.

The mobile barrier according to the present invention prevents bar A from hitting obstacles and is able to detect obstacles 0 of small size and made of any kind of material, since, in the preferred embodiment, ultrasounds are used.