Loading plate for weighing systems of vehicles in motion and related constraint system
The field of application of present invention relates to weighing systems of vehicles in motion also called WIM systems (Weigh In Motion). The indicated WIM system foresees the placement of a metal plate to the street level, above which vehicles to be weighed may transit, and this metal plate, which is also called loading plate, is mounted above a cavity obtained on the road surface so that it can flex at the passage of the vehicles above it. The system provides that the measurement of the deflection of said loading plate is carried out with the aid of suitable sensors, and that the estimated weight is obtained through the modeling of the flexing of said loading plate depending on the weight of the vehicle passing over. The invention discloses a particularly advantage configuration to achieve a weighing system that can be modelled with the required accuracy.
1. A dynamic weighing system for vehicles in motion ( 100 ) comprising a substantially rectangular loading plate ( 110 ), covering the entire width of a way which the vehicles to be weighed can pass through, and wherein said loading plate ( 110 ) has the following features:
a flat bottom face ( 113 ), substantially rectangular, having a width, along a driving direction, said width is substantially perpendicular to a width of a covered way and is greater than said width along a driving direction of its upper face ( 111 ), wherein said upper face comes in contact with a vehicle's wheel to be weighed;
said flat bottom face ( 113 ) has two long edges which support said loading plate ( 110 ) over a cavity ( 103 ) obtained in the ground underlying said loading plate ( 110 ), and wherein said long edges are substantially perpendicular to the driving direction of a vehicle,
and wherein each of said two long edges of said loading plate ( 110 ) has a vertical projection ( 101 ) of said upper face ( 111 ) on said flat bottom face ( 113 ) and wherein said vertical projection does not intersect areas of said bottom face ( 113 ) in which said loading plate ( 110 ) is supported; and
wherein the deformation of said loading plate ( 110 ) is measured to determine a weight of a passing vehicle on said loading plate ( 110 ).
2. The dynamic weighing system for vehicles in motion ( 100 ) according to claim 1 , wherein said loading plate ( 110 ) has connecting surfaces on an access side ( 102 ) of said loading plate ( 110 ) between said upper face ( 111 ) and said bottom face ( 113 ); wherein said connecting surfaces are made a plane surface ( 112 ) perpendicular to said upper face ( 111 ) of said loading plate ( 110 ) and by a slanted surface forming a protruding part.
3. The dynamic weighing system for vehicles in motion ( 100 ) according to claim 1 , wherein said loading plate ( 110 ), when installed and secured to a road surface ( 200 ), is also bound to said road surface ( 200 ) by means of constraint elements ( 120 ) attached to the road surface ( 200 ) itself, installed in a position adjacent to the access side ( 102 ) of the loading plate ( 110 ) and forming, in the upper part, a continuous plane formed by the road surface ( 200 ), by said constraint elements ( 120 ) and by the upper face ( 111 ) of the loading plate ( 110 ).
4. The dynamic weighing system for vehicles in motion ( 100 ) according to claim 3 , wherein said constraint elements ( 120 ), when installed and secured to the road surface ( 200 ), are positioned partially overlying the protruding part of the bottom face ( 113 ) of the loading plate ( 110 ) along the access sides ( 102 ); and wherein said constraint elements ( 120 ) prevent said protruding edges of the bottom face ( 113 ) to be loaded with weight forces of a vehicle passing over said dynamic weighing system.
5. The dynamic weighing system for vehicles in motion ( 100 ) according to claim 3 , wherein said constraint elements ( 120 ), when properly installed and secured to the road surface ( 200 ), each have a horizontal plane surface ( 121 ) approximately co-planar and continuous with said road surface ( 200 ), and a vertical plane surface ( 122 ) forming a right angle with said horizontal surface ( 121 ), and said vertical plane surfaces ( 122 ) of said constraint elements ( 120 ) are laid in correspondence and parallel to the plane surfaces ( 112 ) of said loading plate ( 110 ) that compose said surfaces of connection between the upper and the bottom faces of the loading plate ( 110 ); and wherein said vertical surfaces ( 122 ) have a surface area not greater than the surface of said orthogonal surfaces ( 112 ) to which they are opposed.
6. The dynamic weighing system for vehicles in motion ( 100 ) according to claim 1 , further comprising a seal, made of non-rigid material, which is interposed between said vertical surface ( 122 ) of said constraint element ( 120 ) and said vertical surface ( 112 ) of said loading plate ( 110 ).
7. The dynamic weighing system for vehicles in motion ( 100 ) according to claim 1 , wherein said cavity ( 103 ) is containing all components of said dynamic weighing system for vehicles in motion ( 100 ) are installed and correctly mounted, and wherein said cavity ( 103 ) is fully open below the vertical projection of said upper face ( 111 ) of said loading plate ( 110 ); and wherein said cavity ( 103 ) is deep in the ground so that the bottom of said cavity ( 103 ) does not come into contact with the bottom face ( 113 ) of said loading plate ( 110 ), even when it undergoes its maximum allowable bending down when a vehicle is transiting on the dynamic weighing system for vehicles in motion ( 100 ).
8. The dynamic weighing system for vehicles in motion ( 100 ) according to claim 1 , wherein said loading plate ( 110 ) is coupled to at least one FBG (Fiber Bragg Grating) sensor for a measurement of a deformations of the loading plate ( 110 ) when a vehicle passes over it.