Light controlled electrical system and relay therefor

Claim 1

A LIGHT AND MANUALLY CONTROLLED ELECTRICAL SYSTEM COMPRISING: LIGHT SENSITIVE MEANS; A RELAY HAVING AN OPERATING COIL; MEANS COUPLING SAID LIGHT SENSITIVE MEANS AND SAID COIL FOR ENERGIZING THE SAME RESPONSIVE TO A CHANGE IN LIGHT FROM A FIRST TO A SECOND LEVEL SENSED BY SAID LIGHT-SENSITIVE MEANS; AN OUTPUT CIRCUIT FOR CONNECTION TO A LOAD; SAID RELAY HAVING CONTACTS FOR COUPLING SAID OUTPUT CIRCUIT TO A SOURCE OF ENERGIZING POTENTIAL RESPONSIVE TO ENERGIZATION OF SAID COIL; A SECOND RELAY HAVING AN OPERATING COIL COUPLED ACROSS SAID OUTPUT CIRCUIT AND ENERGIZED RESPONSIVE TO CLOSING OF THE CONTACTS OF SAID FIRST RELAY, SAID SECOND RELAY HAVING CONTACTS COUPLED TO BYPASS SAID CONTACTS OF SAID FIRST-NAMED RELAY AND DIRECTLY TO COUPLE SAID OUTPUT CIRCUIT TO SAID SOURCE RESPONSIVE TO ENERGIZATION OF THE COIL OF SAID SECOND RELAY WHEREBY THE COUPLING OF SAID CIRCUIT TO SAID SOURCE AND ENERGIZATION OF THE COIL OF SAID SECOND RELAY ARE MAINTAINED DESPITE DEENERGIZATION OF THE COIL OF SAID FIRST-NAMED RELAY RESPONSIVE TO RETURN OF THE LIGHT TO SAID FIRST LEVEL; TIME DELAY MEANS COUPLED IN CIRCUIT WITH THE COIL OF SAID SECOND RELAY FOR DEENERGIZATION THE SAME A PREDETERMINED TIME FOLLOWING DEENERGIZATION OF THE COIL OF SAID FIRST-NAMED RELAY; AND MANUALLY ACTUATED SWITCH MEANS COUPLING SAID SOURCE TO SAID OUTPUT CIRCUIT FOR SELECTIVELY ENERGIZING THE SAME.