Process and apparatus for measuring the dynamic loads applied to a highway by the road traffic
First Claim
1. A process for measuring the dynamic loads applied to a highway by the road traffic, in which a rectilinear piezo-electric cable is placed across the highway so that the wheels of the axles of the vehicles circulating on the highway subject it, upon passage thereof, to a pressure to which it responds by the emission of an electrical pulse and the corresponding dynamic load is calculated from the parameters of said pulse, whilst the speed of the vehicle is measured with the aid of the pulse delivered by a second rectilinear piezo-electric cable disposed on the highway at a certain distance from the first-mentioned cable, by determination of the duration of the time gap separating the appearance of the pulses respectively furnished by the two cables for the same wheel,the dynamic load being deduced from the area of the contour, with respect to time, of the pulse delivered by the first-mentioned cable and from the speed of the vehicle, by making the product of said area by said speed.
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Accused Products
Abstract
This invention relates to a process for measuring the dynamic load exerted on a highway by the axles of the vehicles circulating thereon. Two piezo-electric cables sensitive to the pressure of the axles, furnish, upon passage thereof, a weight information pulse and a speed information pulse, respectively. Signals representing respectively the area of the pulse and the duration of the time gap separating the pulses, are applied to a divider which effects the quotient thereof and furnishes a signal representing the dynamic load.
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Citations
11 Claims
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1. A process for measuring the dynamic loads applied to a highway by the road traffic, in which a rectilinear piezo-electric cable is placed across the highway so that the wheels of the axles of the vehicles circulating on the highway subject it, upon passage thereof, to a pressure to which it responds by the emission of an electrical pulse and the corresponding dynamic load is calculated from the parameters of said pulse, whilst the speed of the vehicle is measured with the aid of the pulse delivered by a second rectilinear piezo-electric cable disposed on the highway at a certain distance from the first-mentioned cable, by determination of the duration of the time gap separating the appearance of the pulses respectively furnished by the two cables for the same wheel,
the dynamic load being deduced from the area of the contour, with respect to time, of the pulse delivered by the first-mentioned cable and from the speed of the vehicle, by making the product of said area by said speed.
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9. A sensor for measuring the dynamic loads applied to a highway by the road traffic, comprising a rectilinear piezo-electric cable adapted to be placed across the highway so that the wheels of the axles of the vehicles circulating on the highway subject the cable, upon passage thereof, to a pressure to which it responds by the emission of an electrical pulse, said sensor comprising
a piezo-electric cable; -
a long rigid support subjacent the cable; and a material having a modulus of elasticity insensitive to temperature, the material being disposed within the support and encasing and supporting the cable, so that the cable is insensitive to the effects of the longitudinal deflections of the highway. - View Dependent Claims (10, 11)
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Specification