Condition responsive electrical system

Claim 1

AN INCREMENTAL POSITION MEASURING SYSTEM, COMPRISING: DRIVE MEANS; A SCREW COUPLED TO AND ROTATED BY SAID DRIVE MEANS; A MEMBER IN THREADED ENGAGEMENT WITH SAID SCREW FOR MOVEMENT AXIALLY OF SAID SCREW WHEN SAID SCREW IS ROTATED; INCREMENTAL DISPLACEMENT DETECTOR MEANS INCLUDING A ROTARY TRANSDUCER COUPLED TO AND ROTATED BY SAID SCREW, FOR PRODUCING DISCRETE ELECTRICAL SIGNALS WITH EACH PREDETERMINED ANGULAR INCREMENT OF DISPLACEMENT OF SAID SCREW AND FOR PRODUCING A SEPARATE ELECTRICAL SIGNAL ONCE EACH REVOLUTION OF SAID SCREW; SWITCH MEANS DISPOSED IN THE PATH OF MOVEMENT OF SAID MEMBER AND OPERATED THEREBY TO PRODUCE A SWITCH SIGNAL WHEN SAID MEMBER IS IN A PREDETERMINED POSITION; CIRCUIT MEANS COUPLED TO SAID SWITCH MEANS AND TO SAID INCREMENTAL DISPLACEMENT DETECTOR MEANS AND RESPONSIVE TO SAID SWITCH SIGNAL AND SAID SEPARATE ELECTRICAL SIGNAL FOR PRODUCING A CONTROL SIGNAL; AND COUNTER MEANS COUPLED TO SAID CIRCUIT MEANS AND TO SAID INCREMENTAL DISPLACEMENT DETECTOR MEANS TO COUNT SAID DISCRETE ELECTRICAL SIGNALS UNDER THE CONTROL OF SAID CONTROL SIGNAL.