Patent Description:
Furthermore, the present invention relates to a service vehicle, particularly to a vehicle in service on motorways, on which a device for determining the salt concentration is mounted.

As is well-known, in cold regions subject to ice formation it is usual to spread an anti-freezing salt on the road surface during the winter season in order to prevent the formation of ice sheets and improve road traffic safety.

Since this anti-freezing salt, usually consisting of sodium chloride or calcium chloride, has a certain environmental impact it is desirable to spread the necessary minimum amount of salt on the road surface to ensure the road traffic safety.

In order to do this, it is therefore necessary to accurately determine in advance the residual salt concentration on the road surface so that it may be established the road surface areas requiring salt spreading and the actual amount of salt to spread in these areas.

To meet this need, devices for determining the residual salt concentration on the road surface have been developed, said devices are mounted on a vehicle, especially on a service vehicle, and perform the measurements on the road at predetermined time intervals when the vehicle service crosses said road.

Such measurement devices are substantially based on reflectance measurements and comprise an element for transmitting the light generated by a light source on the road surface, and a detector or sensor for detecting the reflected light from the radiated road surface area, where such reflected light can be correlated to the salt concentration contained in the liquid (water) on the road surface measured area.

However, such measurement devices are expensive and frequently do not allow precise measurements because the amount and/or angle of the reflected light measured on the road surface is often dependent on the particular conditions of the measured surface, for example the presence of debris or liquids such as oils and/or fuel. In addition, in the case of a substantially dry road surface, determining the salt concentration with these devices is very difficult or impossible.

<CIT> describes a soil conductivity measuring device that provides electrodes in the shape of wheels mounted on an agricultural vehicle. The measurement is performed by applying a current to the electrodes when they are in contact with the soil or are also at a certain depth therein, and the conductivity of the soil is measured as a variation of the observed potential after current application.

<CIT> describes a measurement device for the salt concentration on a road surface that provides measuring electrodes arranged to contact a vehicle tire in order to obtain an independent measurement of the road surface condition.

<CIT> describes a measurement apparatus for the salt concentration on a road surface having a wheel rotating in contact with the road surface to collect the moisture on the road surface and measuring electrodes in contact with the surface of said wheel.

The main purpose of this invention is therefore to provide a device for measuring the salt concentration on a road surface mountable on a service vehicle and which allows more accurate measurements of the salt concentration during the service vehicle progress on the road, so as to overcome the drawbacks aforementioned with reference to the prior art.

Another purpose of this invention is to provide a device for measuring the salt concentration on the road surface, as aforementioned, which can be easily used and produced at low costs.

The solution idea behind this invention is to determine the salt concentration on the road surface with a device mountable on a service vehicle capable of making electrical measurements instead of reflective measurements.

Based on this solution, the purposes mentioned above are primarily achieved by a device for determining the salt concentration on a road surface, the device comprising:.

It has surprisingly been found that a device as above allows to accurately detect the residual salt concentration on the road surface through variation measurements of electrical properties while the service vehicle on which the device is mounted advances on that road surface.

In particular, it has been found that by applying a voltage or an electric current between the electrodes of the device at least one electrical property of the circuit, such as electrical resistance, conductivity, capacity, dielectric constant, voltage etc., undergoes a variation which essentially depends on the salt concentration on the road surface between the electrodes and is not influenced by the road surface specific conditions, such as humidity, debris, etc..

Therefore, the present invention allows to accurately determine through the measurements with the device of the invention on a given road section, the sufficient amount of salt to spread in that road section in order to ensure the road traffic safety, thereby significantly reducing the environmental impact resulting from the salt spreading and its related costs.

According to a preferred embodiment, the determination of the salt concentration on the road surface occurs by means of a double voltage reading (voltage variation between the electrodes measured against a voltage applied to the circuit) and current (current variation against a current applied to the circuit). This allows to advantageously determine the salt concentration even in conditions of dry road surface where the measurement through the current variation could be impossible and unsatisfactory due to a reduced or absent conductivity of the dry road surface section that is between the measuring electrodes.

According to one embodiment of the present invention, the device comprises a display unit connected to said command and control unit for displaying salt concentration values received and processed by said command and control unit.

The purposes mentioned above are also achieved by a service vehicle comprising a device as described.

In particular, the device according to the invention can be mounted so that the electrodes and their respective handling components are mounted on any outer part of the vehicle, for example an outer lateral part of the vehicle or preferably under the vehicle platform.

The purposes mentioned above are also achieved by a method for determining the salt concentration on a road surface when crossed by a service vehicle comprising a device as described above, the method comprising the steps of:.

According to one embodiment, the method further comprises the displaying of salt concentration data related to the performed measurements of said variation of the electric property.

According to one embodiment, the electric property is chosen from electrical conductivity, electrical resistance, electrical capacity, voltage and dielectric constant.

The characteristics and advantages of the present invention will result from the description, done below, of some preferred embodiments given for information and non-limiting purposes with reference to the attached drawings.

With reference to <FIG>, a device for determining the salt concentration on the road surface according to an embodiment of the invention is globally indicated by <NUM>.

Device <NUM> comprises a plate <NUM> having a first portion 2a intended to be fixed to a vehicle <NUM>, for example a vehicle in service on motorways, and a mobile portion 2b tilting with respect to the first portion 2a around a hinge line <NUM> joining the first portion 2a and the second portion 2b of the plate <NUM>. To the second portion 2b of the plate <NUM> are fixed two tubular electrodes <NUM> with a substantially cylindrical section parallel to each other protruding of a predetermined section from the free end of the second portion 2b of the plate, that is protrude from the side opposite to the side joining the second portion 2b to the first portion 2a through the hinge <NUM>.

More specifically, the second portion 2b of the plate <NUM> is movable between a resting position in which it is substantially on the same plane as the first portion 2a of the plate <NUM> so that, in use, it turns out to be raised with respect to the road surface <NUM> of the road crossed by the service vehicle <NUM>, and an operating position in which the second portion 2b of the plate <NUM> is, in use, lowered (that is displaced below) with respect to the first portion 2a so as to allow the electrodes <NUM> to contact the surface <NUM> of the road crossed by the vehicle <NUM> and eventually crawling on it as this vehicle <NUM> progress. In this operating position, the second portion 2b of the plate <NUM> can be substantially perpendicular to the first portion 2a of the plate <NUM> except for any roughness of the road surface <NUM>.

The displacement of the second portion 2b of the plate <NUM> between the resting position and the operating position can be performed by means of a motor <NUM> electrically commanded by a command and control unit (which will be described below) and hinged through a hinge <NUM> to a support bracket <NUM> fixed on the first portion 2a of the plate <NUM> and protruding superiorly therefrom. In particular, the motor <NUM> is provided with a sliding rod <NUM> partially protruding from the body of the motor <NUM> and hinged to the free end, through a hinge <NUM>, to a plate-like element <NUM> fixed on the second portion 2b of the plate <NUM> and protruding substantially perpendicularly from the latter.

In the resting position of the plate <NUM>, the rod <NUM> is in a retracted position resulting almost entirely embedded in the body of the motor <NUM> while the motor <NUM> is in a raised position away with respect to the upper surface of the first portion 2a of the plate <NUM> (<FIG>). In the passage from the resting position to the operating position, the motor <NUM> is commanded so as to allow the sliding of the rod <NUM> outwards from an opening 5a of the motor body <NUM> and the lowering of the motor body <NUM> towards the first portion 2a of the plate <NUM> by rotary movement around the axis of the hinge <NUM> of the bracket <NUM>. This entails the simultaneous lowering of the portion 2b of the plate <NUM> until it reaches its operating position with the electrodes <NUM> in contact with the road surface <NUM>.

Vice versa, in the passage from the operating position to the resting position, the motor <NUM> is commanded so as to allow the partial withdrawal of the rod <NUM> in the body of the motor <NUM> through the opening 5a and the raising of the motor body <NUM> away from the first portion 2a of the plate <NUM> by rotary movement around the axis of the hinge <NUM> of the bracket <NUM>. This entails the simultaneously raising of the portion 2b of the plate <NUM> until it reaches its resting position in which it is substantially on the same plane as the first portion 2a of the plate <NUM> with the electrodes <NUM> in a raised position with respect to the road surface <NUM> and therefore no longer in contact with it.

In the present embodiment, each electrode <NUM> has advantageously a first portion 4a fixed to the second portion 2b of the plate <NUM> and a second portion 4b protruding from the second portion 2b of the plate <NUM> so as to allow it to contact the road surface <NUM>, the second portion 4b of each electrode <NUM> being elastically connected, through a spring <NUM>, to the respective first portion 4a and having a greater diameter than that of the first portion 4a so as to allow it to slide elastically over the first portion 4a.

In this way, in the operating position with the electrodes <NUM> in contact with the road surface <NUM>, the roughness of the road surface experienced by the device <NUM> during the vehicle <NUM> progress is compensated by the elastic sliding movement of the second portion 4b of the electrodes <NUM> on the respective portions 4a and eventually, within certain limits, from the tilting movement of the portion 2b of the plate <NUM> around the hinge <NUM> between the first portion 2a and the second portion 2b of the plate <NUM> and around the hinge <NUM> between the plate-like element <NUM> and the rod <NUM>, while the portions 4b of the electrodes <NUM> are continuously kept in contact with the road surface <NUM>.

Electrodes <NUM> can be made with any electrically conductive material, metallic or non-metallic and preferably with appropriate characteristics of abrasion resistance and mechanical resistance to functional shocks due to the use of device <NUM> according to the invention.

Advantageously, electrodes <NUM> can be made of graphene.

Device <NUM> can be mounted on any outer part of the vehicle <NUM>, with special reference, to the components of the same described above.

In particular, as illustrated in <FIG>, the device <NUM> can be advantageously mounted under the platform <NUM> of the service vehicle <NUM> in a spaced position therefrom, for example on a transverse bar <NUM> held in a spaced relationship from the platform <NUM> by spacers <NUM> conventionally fixed to the platform <NUM>, for example by welding, fixing with screws/bolts or other functionally equivalent systems.

In this regard, the plate <NUM> bearing the electrodes <NUM> and the components described above for its handling between the resting position and the operating position can be fixed in a conventional manner for example by fixing with screws/bolts or other functionally equivalent systems, with its first portion 2a on the upper part of the bar <NUM> exposing the second portion 2b and the hinge <NUM> towards the front or rear side of the vehicle <NUM>, preferably towards the rear side.

The device <NUM> further comprises an electrical circuit <NUM> to which electrodes <NUM> are connected. A schematic diagram of an embodiment of this electrical circuit is shown in <FIG>.

Circuit <NUM> comprises a resistor <NUM> having a constant resistance value, an oscillation unit <NUM>, a voltage and/or electric current measuring unit <NUM> and an A/D conversion unit <NUM> and a command and control unit <NUM> (CPU). The resistor <NUM>, the oscillation unit <NUM>, and the voltage and/or electric current measuring unit <NUM> are electrically connected to each other and to the electrodes <NUM> and the A/D conversion unit <NUM> is electrically connected to the voltage and/or electric current measuring unit <NUM>. Furthermore, the A/D conversion unit <NUM> and the oscillation unit <NUM> are electrically connected to the command and control unit <NUM> bidirectionally through a bus <NUM>.

To the command and control unit <NUM> are also electrically connected, through the bus <NUM>, an input interface <NUM>, an output interface <NUM> and optionally one or more sensors mountable on the service vehicle <NUM> for measuring other parameters optionally correlated with the determination of the salt concentration on the road surface. For example, in the present embodiment, the command and control unit <NUM> is also connected to a sensor <NUM> for measuring the external temperature, to a sensor <NUM> for measuring the road surface temperature, to a sensor <NUM> for measuring humidity and to a sensor <NUM> for measuring the dew point, also called frost point if it is at a temperature below <NUM>.

The output interface <NUM> is also electrically connected to a display unit <NUM> for displaying the data of the measurements performed with special reference to the determination of the salt concentration on the road surface.

Regarding the determination of the salt concentration on the road surface according to the invention, the determination is performed with the vehicle <NUM> moving on the road surface section <NUM> on which the residual salt concentration is to be determined by lowering the electrodes <NUM> by means of the motor <NUM> so as to place them in their operating position in contact with the road surface <NUM>, whenever a measurement is desired.

In a first step, the operator/driver of the vehicle <NUM> can send to the command and control unit <NUM> a start signal or instructions to perform the measurement of the salt concentration on the road surface <NUM> through the input interface <NUM>. The command and control unit <NUM> can therefore control the electrical connection of the oscillation unit <NUM> and the resistor <NUM> to the electrodes <NUM> and command the sending of a predetermined voltage (for example <NUM> V) and/or a predetermined electric current to the electrodes <NUM> by means of the oscillation unit <NUM>.

Then, the command and control unit <NUM> can command to the voltage measurement unit <NUM> to measure the voltage and/or the electric current at the resistor <NUM>. Since the voltage or current measured at the resistor <NUM> varies as a function of the resistance between the electrodes <NUM> which, in turn, depends on the salt concentration in the saline film between the electrodes, the measurement of the voltage and/or electric current at the resistor <NUM> indirectly provides a measurement of the residual salt concentration on the road surface <NUM> between the electrodes <NUM>.

Data/signals of the measurement performed by the voltage or current measurement unit <NUM> are sent to the command and control unit <NUM> which can also process them in correlation with the data/signals of external temperature measured by sensor <NUM>, of road surface temperature measured by the sensor <NUM>, external humidity measured by the sensor <NUM> and/or dew point/frost point measured by the sensor <NUM>.

The processing may also include a comparison with reference data of the saline concentration optionally in correlation with one or more of the parameters indicated above, that is external temperature, road surface temperature, external humidity and/or dew point/frost point.

The processing performed by the command and control unit <NUM> results in an electrical signal related to the salt concentration measured on the road surface <NUM> which is sent to the output interface <NUM> and, from this, to the display unit <NUM>.

The display <NUM> can show the salt concentration measured on the road surface <NUM> in any desired form, for example as a numeric value, percentage, dedicated graph, light and/or sound indication, eventually with colors and/or sounds which vary as a function of predetermined intervals of saline concentration or other functionally equivalent systems able to provide the operator with rapid feedback or indication of the measured salt concentration.

It should be noted that the command and control unit <NUM> can also separately process the data/ signals received from each of the sensors <NUM>, <NUM>, <NUM> and <NUM> and sends corresponding signals to the output interface <NUM> and, from this, to the display <NUM> for displaying in any desired form the measurements performed by the sensors of <NUM>, <NUM>, <NUM> and <NUM>.

Furthermore, the command and control unit <NUM> is provided with at least one memory containing predefined programs and this memory can also be of a writable type to record, for example, the data of the displayed measurements which, in turn, can be read from an electronic media (for example computer, tablet, smartphone or similar) and/or printed as required.

Advantageously, the display <NUM> can be mounted in the cockpit of the vehicle <NUM>, for example on the dashboard, while the sensors <NUM>, <NUM>, <NUM> and <NUM> are mounted on the outer part of the vehicle <NUM> in a suitable position for their functioning, for example on an outer mirror of the vehicle <NUM>.

Furthermore, the display <NUM> can be equipped with a router for the transmission of the measured data to a remote computer (server) which, in turn, can provide real-time viewing, storage and/or allow access to the detection history. The router can operate with conventional transmission protocols, for example with LTE or GPS transmission.

<FIG> and <FIG> illustrate further embodiments of the device for determining the salt concentration on the road surface according to the present invention.

To the elements of these further embodiments of the device according to the invention which are structurally and/or functionally equivalent to corresponding elements of the device <NUM>, described above, will be assigned the same numbers of the latter in the description below. Furthermore, for brevity, these elements of these further embodiments will not be further described unless necessary for the understanding of the present invention.

<FIG> illustrate a device for determining the salt concentration on the road surface according to a further embodiment of the invention, which is globally indicated by <NUM>.

The device <NUM> differs from the device <NUM> described above in that the electrodes are in the shape of cables <NUM> of conductive material, for example a metallic material, passing inside first tubular sections <NUM> and second tubular sections <NUM> fixed to the first portion 2a and to the second portion 2b of the plate <NUM> in a manner per se conventional, respectively.

In particular, an end portion 51a of the cables <NUM> protrudes of a predetermined length from the end of the second tubular sections <NUM> to face, in use, towards the road surface <NUM> so as to put the cables <NUM> in contact with the road surface <NUM> in the operating position of the device <NUM>. Differently, the opposite end portion of the cables <NUM> protrudes from the first tubular sections <NUM> and can be wrapped in respective reels (not shown) providing a reserve of said cables.

Advantageously, the cables <NUM> can slide by dragging inside the respective tubular sections <NUM>, <NUM> by means of gear wheels <NUM> protruding inward of the first tubular sections <NUM> from corresponding openings made thereon and in pressure abut against the cables <NUM>. These gear wheels <NUM> are supported in pairs by respective support elements <NUM> transversely fixed on the first portion 2a of the plate <NUM> straddling the first tubular sections <NUM> and can be operated by respective motorized means <NUM>, even they supported on the supporting elements <NUM> and in electrical communication with the command and control unit <NUM>.

The device <NUM> further comprises sensors <NUM> fixed on the second portion 2b of the plate <NUM> near respective second tubular sections <NUM> for detecting the presence or absence of the protruding part 51a of the cables <NUM> or a reduction in the length of this protruding part 51a below a predetermined minimum value. The sensors <NUM> are also in electrical communication with the command and control unit <NUM>.

In the operating position of the device <NUM>, the protruding portion 51a of the cables <NUM> crawls on the road surface <NUM> due to the progress of the vehicle <NUM> and could break or deteriorate reducing the useful length for the measurement of the salt concentration. Therefore, whenever this circumstance occurs, the sensors <NUM> detect the absence or reduction below a predetermined minimum length of the protruding portion 51a of the cables <NUM> transmitting a signal to the command and control unit <NUM> which, in turn, provides to command the actuation of the motorized means <NUM> and their respective gear wheels <NUM>. The gear wheels <NUM> therefore, acting on the portions of the cables <NUM> which are inside the first tubular sections <NUM>, push the cables <NUM> towards the second tubular sections <NUM> causing at the same time the (partial) unwrapping of the reserve of said cables <NUM> from the respective reels and thus restoring the terminal portion 51a of the cables <NUM> protruding from the second tubular sections <NUM>.

Upon achievement of a predetermined length of this protruding portion 51a of the cables <NUM>, the sensors <NUM> transmit a corresponding signal to the command and control unit <NUM> that command the stop of the motorized means <NUM>.

In this way, with an appropriate reserve of cables, it is possible to advantageously perform measurements of the salt concentration for relatively long periods without interruptions due to the need to replace damaged electrodes if any.

It should also be noted, advantageously, that in the present embodiment the ends of the second tubular sections <NUM> facing, in use, towards the road surface <NUM> are connected to cushioning springs <NUM> to compensate for the possible bumps deriving from the roughness of the road surface experienced by the device <NUM> during the vehicle <NUM> progress together, within certain limits, with the tilting movement of the portion 2b of the plate <NUM> around the hinge <NUM> between the first portion 2a and the second portion 2b of the plate <NUM> and the hinge <NUM> between the plate-like element <NUM> and the rod <NUM>, while the protruding portions 51a of the cables <NUM> are continuously kept in contact with the road surface <NUM>.

<FIG> illustrates a device for determining the salt concentration on the road surface not according to the invention, the device being globally indicated by <NUM> and being shown mounted on a service vehicle <NUM>.

The device <NUM> differs from the device <NUM> described above in that the plate <NUM> with the handling components associated with it are replaced by two electrodes in the shape of flexible ropes <NUM> of conductive material connected to an electrical circuit, for example like the one described above. These ropes <NUM> can pass through corresponding holes made on the lower side of the platform of the vehicle <NUM> and can be associated with motorized means (not shown) in communication with the command and control unit <NUM> to be moved from a resting position in which they are withdrawn inside the vehicle <NUM> or raised so as to be in a spaced relationship with respect to the road surface <NUM> and an operating position in which the ropes <NUM> are lowered so as to contact the road surface <NUM> in order to measure the salt concentration.

The device <NUM> differs from the device <NUM> described above in that the plate <NUM> with the handling components associated with it are replaced by two electrodes in the shape of flexible tubes <NUM> of conductive material connected to an electrical circuit, for example like the one described above. These flexible tubes <NUM> can pass through corresponding holes made on the lower side of the platform of the vehicle <NUM> and can be associated with motorized means (not shown) in communication with the command and control unit <NUM> to be moved from a resting position in which they are withdrawn inside the vehicle <NUM> or raised so as to be in a spaced relationship with respect to the road surface <NUM> and an operating position in which the flexible tubes <NUM> are lowered so as to contact the road surface <NUM> in order to measure the salt concentration.

<FIG> illustrate a device for determining the salt concentration on the road surface according to a further embodiment of the invention, the device being globally indicated by <NUM> and being shown also mounted on a service vehicle <NUM>.

The device <NUM> differs from the device <NUM> described above in that the electrodes are in the shape of wheels <NUM> comprising conductive material, for example a metallic material, which are rotatably connected to a respective support <NUM> which is, in turn, fixed, for example in a removable way, to the second mobile portion 2b of the plate <NUM>. The wheels <NUM> are in electrical communication with the command and control unit <NUM> and protruding below from the free end of the second mobile portion 2b of the plate <NUM> so as to contact the road surface <NUM> in the operating position of the plate <NUM> for the measurement of the salt concentration.

The device <NUM> further comprises sensors <NUM> fixed on the second portion 2b of the plate <NUM> near the supports <NUM> with their respective wheels <NUM> and are in electrical communication with the command and control unit <NUM>.

The sensors <NUM> can detect the wear wheels <NUM> during the operation of the device <NUM> and can transmit a signal to the command and control unit <NUM> upon achievement of a predetermined minimum thickness of the wheels <NUM> tread. This signal can be viewed on the display <NUM> informing the operator of the need to replace the wheels <NUM>.

Advantageously, the wheels <NUM> can be fixed to their respective supports <NUM> through cushioning elements (springs) to compensate the road roughness while using the device <NUM> on a moving vehicle <NUM> for determining the salt concentration.

In one embodiment, the wheels <NUM> can be made of a conductive material with high mechanical resistance and durability as graphene. In another embodiment, the wheels <NUM> can be made in the shape of brushes provided with bristles of a conductive material, in particular stainless steel, among which vulcanized rubber is inserted (embedded), for example through known injection processes.

<FIG> illustrate a device for determining the salt concentration on the road surface according to a further embodiment of the invention, the device being globally indicated by <NUM> and being shown mounted on a service vehicle <NUM>.

The device <NUM> differs from the device <NUM> described above for the characteristics described below.

The device <NUM> comprises a support having a first fixed part <NUM> intended to be fixed to a vehicle <NUM>, in particular on the platform outer bottom <NUM> of said vehicle <NUM>, and a second mobile part <NUM> rotatable with respect to the first fixed part around a hinge <NUM> joining the first fixed part and the second mobile part.

In particular, the second mobile part <NUM> comprises an arm <NUM> hinged to the fixed part <NUM> along the hinge <NUM> and connected at its free end to a plurality of electrodes <NUM>.

These electrodes <NUM> are radially placed on a wheel <NUM> and embedded in the material (for example vulcanized rubber) forming the wheel tread <NUM> except for an end portion protruding from the tread <NUM> which, in the operating position of the device <NUM>, comes in contact with the road surface for performing the measurement of the salt concentration.

In the present embodiment, the wheel <NUM> bearing the electrodes <NUM> is hinged between the arms of a bracket <NUM> with a substantially V section and the bracket <NUM> with the interposition of a rotary connector <NUM> which is electrically connected to the electrodes <NUM> and to a command and control unit <NUM>. The bracket <NUM> is, in turn, constrained to a free end portion of the arm <NUM> through a pivot <NUM>.

The arm <NUM> and the wheel <NUM> bearing the electrodes <NUM> are movable in rotation between a resting position in which they are raised with respect to the road surface <NUM> approaching the fixed part <NUM> of the support and arranged substantially near the platform outer bottom <NUM> of the vehicle <NUM>, and an operating position in which they are lowered away from the fixed part <NUM> of the support to allow the electrodes <NUM> to contact the road surface <NUM>.

Advantageously, in the present embodiment, the bracket <NUM> is constrained to the free end portion of the arm <NUM> so as to be rotatable (floating) in both opposite directions with respect to the arm <NUM> around the axis of the pivot <NUM> up to a predetermined angle, for example up to <NUM> °. The rotation limit of the bracket <NUM> with the wheel <NUM>, integral with it, in both opposite directions is determined by a pair of opposing stops <NUM> provided on the free end portion of the arm <NUM> and on which the bracket abuts upon reaching the rotation maximum angle in a given direction.

In this way, in the operating condition of the device <NUM>, the wheel <NUM> bearing the electrodes <NUM> could advantageously follow the tires curvature of the vehicle <NUM> which crosses the road surface on which the salt concentration measurement is to be carried out, thus avoiding localized stresses on the wheel <NUM> due, for example, to dragging and reducing wear so as to increase the service life of the measuring electrodes <NUM>.

The device <NUM> further comprises an extensible (telescopic) piston motor <NUM> operatively connected to a carriage <NUM> sliding along rods <NUM> connected to the fixed part <NUM> of the support <NUM>, the carriage <NUM> being, in turn, connected to the mobile arm <NUM> through a pair of articulated arms <NUM>.

More specifically, each articulated arm <NUM> is hinged to the mobile arm <NUM> and to the carriage <NUM>, at a longitudinal slot <NUM> of the carriage along which it is sliding.

The motor <NUM> is also connected to the command and control unit <NUM> and is commanded by the latter to move the mobile arm <NUM> with the electrodes <NUM> between the resting position and the operating position.

In the passage from the operating position to the resting position, the carriage is moved by the motor <NUM> towards an end section of the rods <NUM> causing the raising of the arms <NUM> with simultaneous sliding of the same along the slots <NUM> and the lifting of the mobile arm <NUM> and of the electrodes <NUM> integral with it from the road surface. Upon reaching the resting position, the articulated arms <NUM> and the mobile arm <NUM> are substantially parallel to the rods <NUM> and near the platform outer bottom <NUM> of the vehicle <NUM>.

Vice versa, in the passage from the resting position to the operating position, the carriage is moved by the motor <NUM> towards a central section of the rods <NUM> causing the sliding of the articulated arms <NUM> along the slots <NUM> with simultaneous lowering of the same and of the mobile arm <NUM> until the electrodes <NUM> integral with it contact the road surface.

The device <NUM> further comprises a pair of conventional shock absorbers <NUM> which are operatively connected to the mobile arm <NUM>. These shock absorbers allow to compensate mechanical stresses deriving from the road surface roughness that the mobile arm <NUM> and the electrodes <NUM> can experience in the measuring operating position during the crossing of the road surface by the vehicle <NUM>.

<FIG> illustrate a device for determining the salt concentration on the road surface comprising two devices <NUM> as described above mounted side by side on a service vehicle <NUM>.

Both devices <NUM> are connected to the command and control unit <NUM> and can be used independently. For example, they can be used simultaneously to have multiple measurements of the salt concentration per unit of monitored road surface, or one of the two devices can replace the other, for example in the event of a malfunction of the latter without having to interrupt the ongoing measurements.

In conclusion, the present invention fully fulfills the purposes and achieves remarkable advantages, among which, in addition to those described above, the fact that the device according to the invention can be made with low costs and is easy to use.

Claim 1:
Device (<NUM>;<NUM>;<NUM>;) for determining the salt concentration on a road surface (<NUM>), the device comprising:
- a plate (<NUM>) having a first portion (2a) adapted to be fixed on an outer part of a service vehicle (<NUM>) and a second portion (2b) tilting with respect to the first portion (2a),
- at least two electrodes (<NUM>;<NUM>;<NUM>) fixed to said second portion (2b) of the plate (<NUM>) and protruding therefrom,
- motorized means (<NUM>, <NUM>) for rotating said second portion (2b) of the plate (<NUM>) between a resting position, in which it is substantially on the same plane as said first portion (2a) of the plate (<NUM>) so that, in use, it is raised with respect to the road surface (<NUM>) crossed by said service vehicle (<NUM>), and an operating position, in which said second portion (2b) of the plate (<NUM>), in use, is lowered so as to allow said electrodes (<NUM>;<NUM>;<NUM>) to contact said road surface (<NUM>) during the advancement of said service vehicle (<NUM>), and
- an electrical circuit (<NUM>) comprising said electrodes (<NUM>;<NUM>;<NUM>;) and a command and control unit (<NUM>) (CPU) arranged for commanding the application of a current or voltage between said electrodes (<NUM>;<NUM>;<NUM>;) when the same are in the aforementioned operating position and for receiving and elaborating data relating to the variation of an electrical property measured in said circuit and correlated to the salt concentration between said electrodes (<NUM>;<NUM>;<NUM>;) so as to determine the salt concertation on said road surface.