Delayed egress exit device

A securing system for a door hinged along one edge to a door frame and secured in a closed condition by a latch along at least one other edge to the door frame and wherein the latch is operated by an associated exit device to unlatch the door to allow the door to move to an open position, the exit device mounted on the door including an actuator member for movement relative to the door from a first position to a second position, a retractor adapted to be operatively connected between the actuator member and the latch for rectilinear movement from a first position to a second position in response to movement of the actuator member, the movement of the retractor being transverse to the movement of the actuator member, the door securing system comprising:

• an electrically energizable locking mechanism adapted to be mounted in the exit device, the locking mechanism including
• a reciprocating plunger for movement transverse to the direction of movement of the retractor between a projected position and a retracted position, the plunger adapted to engage the retractor for preventing operation of the exit device when the plunger is in the projected position for securing the door in the closed condition, the locking mechanism operative to move the plunger to the projected position when energized;
• and
• a time delay circuit connected to the locking mechanism for controlling electrical power supplied to the locking mechanism, the time delay circuit including
• a switch for producing a signal indicating an attempt to open the door, a timer connected to the switch for receiving the signal produced by the switch and starting a predetermined time interval for temporarily delaying deenergization of the locking mechanism for the predetermined time interval after the actuator member is moved toward the second position or to maintain the locking mechanism energized and the plunger engaged to the retractor if the predetermined interval of the time delay circuit is not achieved,
• wherein the time delay circuit interrupts electrical power to the locking mechanism upon expiration of the time interval allowing the exit device to operate to unlatch the door, and wherein the movement of the retractor, actuator and plunger are not all coplanar.

A method for delaying egress through a door pivotally mounted along one edge for movement about an axis, comprising:

• providing an exit device including a housing adapted to be secured to the door surface, a latch bolt disposed at one end of the housing adjacent an edge of the door and movable relative to the housing between a projected position extending outwardly of the housing for latching the door in a closed position and a retracted position where the latch bolt is inside the housing for allowing the door to be opened, an actuator mounted on the housing for movement from a first position to a second position relative to the housing, and a retractor connected between the actuator and the latch bolt for rectilinear movement from a first position to a second position in response to movement of the actuator toward the second position of the actuator, the movement of the retractor being transverse to the movement of the actuator;
• providing an electrically energizable locking mechanism mounted to the housing operative to prevent the latch bolt from moving to the retracted position when energized;
• providing a time delay circuit connected between the locking mechanism and a power source for controlling electrical power supplied to the locking mechanism;
• energizing the locking mechanism for causing a plunger associated with the locking mechanism to move into engagement with the retractor to prevent movement of the retractor when the locking mechanism is energized, the plunger movement being transverse to the direction of movement of the retractor;
• activating the time delay circuit in response to movement of the actuator toward the second position for starting a time interval for temporarily delaying deenergization of the locking mechanism;
• de-energizing the locking mechanism at the end of a predetermined time interval of the time delay circuit causing the plunger to move out of engagement with the retractor for movement of the retractor toward the second position and the latch bolt to the retracted position;
• and
• maintaining the locking mechanism energized and the plunger engaged to the retractor if the predetermined interval of the time delay circuit is not achieved,
• wherein the plunger and the actuator are not all coplanar.