Directional sonic vehicle detector

Claim 1

IN A SYSTEM FOR DETECTING THE PRESENCE OF VEHICLES SELECTIVELY ACCORDING TO EITHER OF TWO GENERALLY OPPOSITE DIRECTIONS OF TRAVEL AS THEY PASS THROUGH A DETECTION ZONE DEFINED BY AN ENERGY BEAM DIRECTED SUBSTANTIALLY TRANSVERSELY ACROSS THEIR PATH THE CONBINATION COMPRISING, TRANSMITTING MEANS FOR TRANSMITTING SAID BEAM WITH A RELATIVELY BROAD SPREAD OF SAID BEAM IN A DIRECTION SUBSTANTIALLY PARALLEL TO THE DIRECTION OF TRAVEL OF SAID VEHICLES, FIRST RECEIVING MEANS INCLUDING A FIRST RECEIVING TRANSDUCER BEING POSITIONED TO RECEIVE A REFLECTION OF SAID TRANSMITTED BEAM FROM A VEHICLE AS IT ENTERS SAID TRANSMITTED BEAMD WHILE TRAVELING IN A PARTICULAR DIRECTION, SECOND RECEIVING MEANS INCLUDING A RECEIVING TRANSDUCER FOR RECEIVING REFLECTIONS OF SAID BEAM FROM SAID VEHICLE ONLY AFTER SAID VEHICLE HAS MOVE FURTHER THROUGH SAID BEAM WHILE TRAVELING IN SAID PARTICULAR DIRECTION, EACH OF SAID RECEIVING MEANS PRODUCING A DISTINCTIVE OUTPUT SIGNAL WHEN SAID BEAM IS REFLECTED TOWARD ITS ASSOCIATED RECEIVING TRANSDUCER, OUTPUT CIRCUIT MEANS BEING CONTROLLED JOINTLY BY THE OUTPUTS OF SAID FIRST AND SECOND RECEIVING MEANS TO A DISTINCTIVE CONDITION INDICATIVE OF THE PASSAGE OF A VEHICLE THROUGH SAID ZONE IN SAID PARTICULAR DIRECTION ONLY WHEN SAID FIRST RECEIVING MEANS RECEIVES A REFLECTION OF SAID BEAM PRIOR TO SAID SECOND RECEIVING MEANS, SAID OUTPUT CIRCUIT MEANS INCLUDING INDICATOR MEANS BEING CONTROLLED TO A DISTINCTIVE CONDITION BY THE OUTPUT OF SAID FIRST RECEIVING MEANS FOR INDICATING THE PASSAGE OF A VEHICLE IN SAID PARTICULAR DIRECTION, AND MEANS CONTROLLED BY SAID SECOND RECEIVING MEANS WHEN SAID SECOND RECEIVING MEANS HAS RECEIVED A REFLECTION OF SAID BEAM AT A TIME WHEN SAID FIRST RECEIVING MEANS HAS NOT YET RECEIVED A REFLECTION OF SAID BEAM FOR PREVENTING SAID INDICATOR MEANS FROM BEING CONTROLLED TO SAID DISTINCTIVE CONDITION BY SAID FIRST RECEIVING MEANS.