Low speed vehicle detection system

Claim 1

A VEHICLE DETECTION SYSTEM OPERABLE TO DETECT THE PASSAGE OF VEHICLES OVER A VEHICLE DETECTOR AT LESS THAN A PRESELECTED VELOCITY, SAID SYSTEM COMPRISING A D.C. POWER SUPPLY, A VEHICLE DETECTOR HAVING FIRST AND SECOND SETS OF CONTACTS, SAID SETS OF CONTACTS POSITIONED TO BE CLOSED SEQUENTIALLY IN OVER-LAPPING FASHION BY THE PASSAGE OF A VEHICLE WHEEL OVER SAID DETECTOR, ONE SIDE OF EACH SET OF SAID CONTACTS BEING CONNECTED TO A COMMON POWER-SUPPLY POTENTIAL AND THE OPPOSITE SIDE OF EACH SET OF CONTACTS BEING CONNECTED BY FIRST AND SECOND CIRCUIT MEANS RESPECTIVELY TO A TIMING CAPACITOR AND VOLTAGE SENSING MEANS HAVING A CONTROL ELEMENT, MEANS CONNECTING SAID CONTROL ELEMENT TO SAID CAPACITOR, SAID SENSING MEANS CONDUCTING CURRENT IN RESPONSE TO A PRE-DETERMINED CHARGE ON SAID CAPACITOR, MEANS CONNECTING SAID CAPACITOR TO THE D.C. POWER SUPPLY WHEREBY SAID CAPACITOR IS NORMALLY CHARGED BY SAID POWER SUPPLY TO HOLD SAID CONTROL ELEMENT AT A SUFFICIENT POTENTIAL TO PREVENT SAID SENSING MEANS FROM CONDUCTING CURRENT, THE CLOSING OF SAID FIRST SET OF CONTACTS ESTABLISHING SAID FIRST CIRCUIT MEANS THROUGH SAID FIRST SET OF CONTACTS TO CHANGE THE CHARGE ON SAID CAPACITOR, THEREBY CHANGING THE POTENTIAL ON SAID CONTROL ELEMENT TOWARD THE POINT WHERE SAID SENSING MEANS BECOMES CONDUCTIVE THE CLOSING OF SAID SECOND SET OF CONTACTS WITHIN A PREDETERMINED TIME INTERVAL ESTABLISHING SAID SECOND CIRCUIT MEANS THROUGH SAID SECOND SET OF CONTACTS TO SAID CAPACITOR TO RESTORE THE CHARGE ON SAID CAPACITOR TO ITS NORMAL VALUE TO PREVENT SAID SENSING MEANS FROM OPERATING, OUTPUT MEANS CONNECTED TO SAID SENSING MEANS AND RESPONSIVE TO THE CURRENT CONDUCTION OF SAID SENSING MEANS TO INDICATE THE PRESENCE OF A SLOWLY-MOVING VEHICLE.