Vehicle speed and spacing measuring device - uses spaced mechanical pulse generators coupled to evaluation circuits which are linked to automatic camera

摘要

The device uses two mechanical pulse generators spaced apart by an accurately measured distance. Each generator supplies a pulse when a vehicle passes over it, with the time interval between the pulses used by an evaluation circuit in conjunction with the known distance between them, to indicate the vehicle speed. Pref. a second evaluation circuit uses the pulse generator pulses to detect the spacing between successive vehicles. The evaluation circuits may be coupled to a camera release circuit supplying a camera trigger pulse when the speed is above a given value or the vehicle spacing is below a given value, to photograph the vehicles concerned.