Signalling apparatus including remote battery recharging system

Claim 1

FOR USE WITH A CENTRAL OBSERVATION STAITON FROM WHICH MONITORED CURRENT IS TRANSMITTED FROM A DIRECT CURRENT SOURCE AND OVER A SIGNALLING WIRE TO A REMOTE STATION HAVING AN ELECTRICALLY POWERED COMPONENT, THE IMPROVED REMOTE STATION CIRCUITRY, COMPRISING AN INPUT TERMINAL FOR CONNECTION TO THE SIGNALLING WIRE, A REFERENCE POTENTIAL TERMINAL, FIRST AND SECOND CIRCUITS BRANCHING FROM SAID INPUT TERMINAL AND CONVERGING TO SAID REFERENCE POTENTIAL TERMINAL, SAID FIRST CIRCUIT COMPRISING A RECHARGEABLE REMOTE STATION BATTERY FOR SUPPLYING ELECTRICAL POWER TO SUCH ELECTRICAL COMPONENT AT THE REMOTE STATION AND RECHARGEABLE BY CURRENT SUPPLIED THERETO BY THE SIGNALLING WIRE SAID BATTERY HAVING TERMINALS CONNECTABLE TO SUCH ELECTRICALLY POWERED COMPONENT, UNIDIRECTIONAL CURRENT CONDUCTING MEANS IN SAID FIRST CIRCUIT IN SERIES WITH SAID REMOTE STATON BATTERY, TO ISOLATE THE FLOW OF THE CURRENT OF SAID REMOTE STATION BATTERY FROM SAID SECOND CIRCUIT AND AN ELECTRICAL ELEMENT IN SERIES WITH SAID RECHARGEABLE BATTERY, SAID ELEMENT BEING CHARACTERIZED BY HAVING RESISTANCE OF A VALUE SELECTED TO ESTABLISH A PREDETERMINED BASIC CURRENT IN THE FIRST SERIES CIRCUIT AND THE SIGNALLING WIRE, BY WHICH A NORMALLY-PERSISTENT CONDITION AT THE REMOTE STATION IS IDENTIFIABLE AT THE OBSERVATION STATION, SAID SECOND CIRCUIT COMPRISING SWITCHING MEANS FOR MAINTAINING SAID SECOND CIRCUIT NORMALLY NONCONDUCTING, AND SENSOR MEANS ELECTRICALLY COUPLED TO SAID SWITCHING MEANS FOR RENDERING SAID SECOND CIRCUIT CONDUCTING WHEN AN ABNORMAL CONDITION IS DETECTED AT THE REMOTE STATION, THEREBY TO INCREASE THE CURRENT FLOW IN THE SIGNALLING WIRE.