Ultrasonic vehicle detection system

Claim 1

IN A SYSTEM FOR DETECTING VEHICLES AS THEY PASS ALONG A PATHWAY AND THROUGH A DETECTION ZONE DEFINED BY AT LEAST ONE ENERGY BEAM, AT LEAST ONE ENERGY TRANSMITTING MEANS INCLUDING A TRANSMITTING TRANSDUCER POSITIONED ALONGSIDE THE PATH TO BE TRAVERSED BY SAID VEHICLE FOR TRANSMITTING SAID BEAM ACROSS SAID PATH TO THEREBY DEFINE SAID DETECTION ZONE, FIRST RECEIVING MEANS INCLUDING A RECEIVING TRANSDUCER POSITIONED ON THE OPPOSITE SIDE OF SAID PATH FOR RECEIVING AND BEING DISTINCTIVELY CONTROLLED BY SAID BEAM TRANSMITTED FROM SAID TRANSMITTING MEANS WHEN NO VEHICLE IS PRESENT, SECOND RECEIVING MEANS ALSO INCLUDING A RECEIVING TRANSDUCER POSITIONED ON THE SAME SIDE OF SAID PATH AS SAID TRANSMITTING MEANS FOR RECEIVING AND BEING DISTINCTIVELY CONTROLLED BY THE REFLECTION OF SAID BEAM FROM A VEHICLE INTERCEPTING SAID BEAM WHILE PASSING THROUGH SAID ZONE, AND REGISTERING MEANS GOVERNED JOINTLY BY SAID FIRST AND SECOND RECEIVING MEANS AND SO CONSTRUCTED AS TO BE CONTROLLED TO A VEHICLE REGISTERING CONDITION ONLY WHEN SAID SECOND RECEIVING MEANS HAVE BEEN DISTINCTIVELY CONTROLLED BY THE RECEPTION OF SAID REFLECTED BEAM AND CONCURRENTLY THEREWITH SAID FIRST RECEIVING MEANS IS NO LONGER DISTINCTIVELY CONTROLLED BY RECEPTION OF SAID BEAM BY REASON OF ITS INTERRUPTION BY SAID VEHICLE.