Station selector apparatus for conveyor installations

Claim 1

A STATION SELECTOR SYSTEM FOR CARRIERS OF A CONVEYOR INSTALLATION OF THE TYPE WHEREIN A SIGNAL FOR ACTUATING A DEVICE IS OBTAINED UPON THE ARRIVAL OF A CARRIER AT THE STATION SELECTED FROM A RESONANT COUPLING BETWEEN A NON-ENERGIZED RESONANT CIRCUIT OF A PICK-UP UNIT MOUNTED ON THE CARRIER AND A DETECTOR UNIT LOCATED AT THE STATION; CHARACTERIZED BY: (A) SAID DETECTOR UNIT INCLUDING AT LEAST ONE OSCILLATION CIRCUIT, (B) MEANS FOR ENERGIZING SAID OSCILLATION CIRCUIT AT A CERTAIN FREQUENCY THROUGH AN IMPEDANCE, (C) SAID DETECTOR UNIT OSCILLATION CIRCUIT COMPRISING A COIL AND A CAPACITANCE CONNECTED IN PARALLEL AND TUNED TO SAID FREQUENCY, (D) BI-STABLE CIRCUIT MEANS WHOSE STATE DEPENDS UPON THE MAGNITUDE OF AN INPUT SIGNAL FOR SENSING A RESONANT COUPLING OF SAID PICK-UP UNIT WITH SAID DETECTOR UNIT AND FOR PRODUCING SAID ACTUATING SIGNAL IN RESPONSE TO SUCH RESONANT COUPLING, (E) AND MEANS CONNECTING SAID ENERGIZED OSCILLATION CIRCUIT TO SAID BI-STABLE CIRCUIT TO SUPPLY THE SIGNAL RESULTING ACROSS THE TUNED COIL AND CAPACITANCE OF THE OSCILLATION CIRCUIT AS A NORMAL INPUT SIGNAL FOR MAINTAINING SAID BI-STABLE CIRCUIT IN ONE STATE WHEREBY SAID BI-STABLE CIRCUIT CHANGES TO ITS OTHER STATE IN RESPONSE TO A DROP IN SAID INPUT SIGNAL RESULTING FROM SAID RESONANT COUPLING.