Control devices for ultraclean facilities

Claim 1

IN COMBINATION WITH AN ACCESS CHAMBER HAVING A CEILING, A FLOOR, SIDE WALLS EXTENDING BETWEEN SAID CEILING AND FLOOR, AND A PLURALITY OF DOORS MOUNTED IN SAID SIDE WALLS, IN COMBINATION, (A) A LIKE PLURALITY OF ELECTRICALLY OPERATED DOOR LOCKS, EACH LOCK BEING ASSOCIATED WITH A CORRESPONDING DOOR WHEREBY WHEN A DOOR IS CLOSED AND ITS CORRESPONDING LOCK IS ENERGIZED SAID CLOSED DOOR IS LOCKED, SAID CLOSED DOOR BEING UNLOCKED WHEN SAID CORRESPONDING LOCK IS DEENERGIZED; (B) A LIKE PLURALITY OF DOOR SWITCHES, EACH SWITCH BEING ASSOCIATED WITH A CORRESPONDING DOOR, EACH SWITCH HAVING A FIRST SWITCH POSITION WHEN ITS CORRESPONDING DOOR IS OPEN AND HAVING A SECOND SWITCH POSITION WHEN ITS CORRESPONDING DOOR IS CLOSED: (C) DOOR LOCKING AND UNLOCKING APPARATUS ELECTRICALLY INTERCONNECTED BETWEEN SAID SWITCHES AND LOCKS, SAID APPARATUS HAVING FIRST MEANS ACTUATED WHEN ONE OF SAID DOORS IS OPENED AND ALL OTHER DOORS ARE CLOSED TO ENERGIZE THE LOCKS OF ALL OTHER DOORS IN ORDER TO LOCK EACH OF SAID ALL OTHER DOORS, SECOND MEANS ACTUATED AFTER SAID FIRST MEANS IS ACTUATED AND SAID ONE DOOR IS CLOSED TO ENERGIZE THE LOCK OF SAID ONE DOOR TO LOCK SAID ONE DOOR, AND THIRD MEANS ACTUATED A PREDETERMINED INTERVAL AFTER SAID FIRST AND SECOND MEANS ARE ACTUATED TO DEACTUATE SAID FIRST AND SECOND MEANS AND DEENERGIZE ALL LOCKS TO UNLOCK ALL OF SAID DOORS; (D) A TIMER FOR DETERMINING THE LENGTH OF SAID INTERVAL, SAID TIMER BEING COUPLED TO SAID THIRD MEANS TO ACTUATE SAME WHEN THE TIMER HAS INDICATED THE EXPIRATION OF SAID INTERVAL; AND (E) FOOT PRESSURE RESPONSIVE MEANS IN THE FLOOR OF SAID CHAMBER WHICH WHEN STOPPED ON COOPERATES WITH THE ACTUATED SECOND MEANS TO CAUSE SAID TIMER TO INITIATE THE TIMING ACTION TO DETERMINE THE LENGTH OF SAID INTERVAL.