Detecting switch means

Claim 1

PROXIMITY SWITCH MEANS FOR DETECTING THE PRESENCE OF A BODY OF MATERIAL AND PERFORMING A CONTROL SWITCHING FUNCTION IN RESPONSE TO A PREDETERMINED PROXIMITY THEREOF COMPRISING A POWER SOURCE, CAPACITIVE SENSING MEANS EFFECTING A CAPACITIVE CHANGE AS A FUNCTION OF THE RELATIVE PROXIMITY THERETO OF A BODY OF MATERIAL, OSCILLATOR MEANS ENERGIZED BY SAID POWER SOURCE EFFECTING AN OUTPUT SIGNAL OF A PREDETERMINED AMPLITUDE OF OSCILLATION IN THE EVENT OF THE ABSENCE OF A BODY OF MATERIAL WITHIN A FIRST PREDETERMINED PROXIMITY OF SAID SENSING MEANS AND EFFECTING A MODULATION OF SAID AMPLITUDE AS A FUNCTION OF THE PROXIMITY OF SAID BODY TO SAID SENSING MEANS WITHIN SAID FIRST PREDETERMINED PROXIMITY, CONTROL OUTPUT MEANS CONNECTED WITH SAID OSCILLATOR MEANS TO RECEIVE SAID OUTPUT SIGNAL INCLUDING BISTABLE MULTIPLE STATE AMPLIFIER MEANS SELECTIVELY SWITCHED BETWEEN SAID STATES UPON THE ADVENT OF A SECOND PREDETERMINED PROXIMITY OF SAID BODY TO SAID SENSING MEANS IN RESPONSE TO A FUNCTIONALLY RELATED SECOND PREDETERMINED AMPLITUDE OF SAID OUTPUT SIGNAL AND PROVIDING A CONTROL SIGNAL IN RESPONSE TO SAID CHANGE OF STATE, AND SWITCH MEANS ENERGIZED BY SAID CONTROL SIGNAL EFFECTING A PREDETERMINED CONTROL SWITCHING FUNCTION, SAID OSCILLATOR MEANS INCLUDING A FEEDBACK CIRCUIT COMPRISING A FOUR TERMINAL IMPEDANCE BRIDGE INCLUDING SAID SENSING MEANS AND A VARIABLE CAPACITIVE SET POINT MEANS AS FIRST AND SECOND LEGS THEREOF AND HAVING THIRD AND FOURTH FIXED IMPEDANCE LEGS, SAID FIXED IMPEDANCE LEGS BEING ENERGIZED BY SAID OUTPUT SIGNAL, SAID FEEDBACK CIRCUIT PROVIDING A REGENERATIVE FEEDBACK SIGNAL ACROSS THE DIAGONAL OF SAID BRIDGE DEFINED BY COMMON CONNECTIONS BETWEEN SAID FIRST AND SECOND LEGS AND SAID THIRD AND FOURTH LEGS, RESPECTIVELY, SAID REGENERATIVE FEEDBACK SIGNAL HAVING AN AMPLITUDE MODULATED AS A FUNCTION OF THE DIFFERENTIAL IMPEDANCE VALUE BETWEEN SAID SENSING AND SAID SET POINT MEANS AND CONTROLLING SAID AMPLITUDE OF OSCILLATION OF SAID OUTPUT SIGNAL, SAID OSCILLATOR MEANS FURTHER INCLUDES FIRST AND SECOND TRANSISTORS HAVING SUBSTANTIALLY IDENTICAL OUTPUT CAPACITANCES, FIRST OUTPUT CIRCUIT MEANS INTERCONNECTING SAID FIRST AND SECOND TRANSISTOR MEANS SUCH THAT THE VOLTAGES ACROSS THE RESPECTIVE OUTPUT CAPACITANCES THEREOF ARE IN PHASE OPPOSITION, TUNED CIRCUIT MEANS COUPLING SAID FIRST OUTPUT CIRCUIT MEANS WITH SAID THIRD AND FOURTH LEGS OF SAID IMPEDANCE BRIDGE, INPUT CIRCUIT MEANS FOR SAID TRANSISTORS INTERCONNECTED WITH SAID IMPEDANCE BRIDGE ACROSS THE SAID DIAGONAL THEREOF PROVIDING SAID FEEDBACK SIGNAL, AND SECOND OUTPUT CIRCUIT MEANS COUPLED WITH SAID TUNED CIRCUIT MEANS TRANSMITTING SAID OUTPUT SIGNAL OF SAID OSCILLATOR MEANS TO SAID CONTROL OUTPUT MEANS.