Apparatus for opening and closing air lock doors

In an air lock with an outer door adapted to open and close in a doorway between an atmospheric region and a transfer chamber, and with an inner door adapted to open and close in a doorway between the transfer chamber and a containment region, a door control system comprising:

• first door-actuating means for operating the outer door between a locked, closed position and an open position;
• means for connecting the first door-actuating means to the outer door;
• second door-actuating means for operating the inner door between a locked, closed position and an open position;
• means for connecting the second door-actuating means to the inner door;
• a drive shaft;
• first clutch means for coupling and decoupling the drive shaft to the first door-actuating means;
• second clutch means for coupling and decoupling the drive shaft to the second door-actuating means;
• a first lead screw coupled to the drive shaft to be rotatably driven thereby;
• first clutch-actuating means for engaging the first clutch means and thereby coupling the drive shaft to the first door-actuating means;
• a first lead screw nut adapted to move in an active range along the lead screw, between a neutral position and one end of the first lead screw, to operate the first clutch-actuating means and the first clutch means, the first clutch means being disengaged when the first lead screw nut is moved in an inactive range between the neutral position and the other end of the first lead screw;
• a second lead screw coupled to the drive shaft to be rotatably driven thereby;
• second clutch-actuating means for engaging the second clutch means and thereby coupling the drive shaft to the second door-actuating means;
• a second lead screw nut adapted to move in an active range between a neutral position medial the ends of the second lead screw and one end of the second lead screw to operate the second clutch-actuating means and the second clutch means, the second clutch means being disengaged when the second lead screw nut is moved in an inactive range between the neutral position and the other end of the second lead screw;
• and
• means coupled to the drive shaft for imparting rotation to the drive shaft and the lead screws coupled thereto,
• wherein the lead screws and lead screw nuts are adapted so that one lead screw nut moves in its active range along its lead screw to operate one door, while the other lead screw nut moves in an inactive range along its lead screw, whereby the other door remains in a locked, closed position.

A door control mechanism for a door that is moved out of a doorway and outwardly from one side of a partition defining the doorway, the partition including two upright, spaced apart door jambs on opposite sides of the doorway, the mechanism comprising:

• a latch arm;
• means for pivotally connecting the latch arm to the door;
• an actuator link;
• a first toggle link coupled between the latch arm and the actuator link;
• a second toggle link with one end coupled to the actuator link and a pivot end for connection to the door;
• means for connecting the pivot end of the second toggle link to the door;
• door actuator means coupled to the actuator link for operating the toggle links between (i) an over-center position where the latch arm engages one of the door jambs to hold the door in a locked, closed position and (ii) a back-from-over-center position where the latch arm is pivoted inwardly from the door jamb and the door actuator means begins to urge the door to its open position,
• wherein the latch arm, the toggle links, the actuator link and the door actuator means are all disposed on the side of the partition opposite the side to which the door is opened, the latch arm, the toggle links and the actuator link being urged through the doorway to the other side of the partition when the door actuator means is operated to urge the door to its open position.

A door control system for operating an outer door of an air lock for entry into the lock chamber from the outside and for operating an inner door for leaving the lock chamber to enter a pressurized region, the door control system comprising:

• first door-actuating means for operating the outer door between a locked, closed position and an open position;
• means for connecting the first door-actuating means to the outer door, this connecting means including latching means driven by the first door-actuating means;
• second door-actuating means for operating the inner door between a locked, closed position and an open position;
• means for connecting the second door-actuating means to the inner door, this connecting means including latching means driven by the second door-actuating means;
• a single drive shaft;
• first clutch means for coupling and decoupling the drive shaft to the first door-actuating means;
• first clutch-actuating means for engaging and disengaging the first clutch means;
• first timing means coupled to the drive shaft to be driven thereby, the first timing means having a portion that advances along a linear path to operate the first clutch-actuating means;
• second clutch means for coupling and decoupling the drive shaft to the second door-actuating means;
• second clutch-actuating means for engaging and disengaging the second clutch means;
• second timing means coupled to the drive shaft to be driven thereby, the second timing means having a portion that advances along a linear path to operate the second clutch-actuating means;
• and
• means coupled to the drive shaft from imparting rotation thereto,
• wherein the first and second timing means are adapted to alternately operate their associated clutch-actuating means to alternately operate the doors.