ELECTRONIC PUSH RETRACTION EXIT DEVICE

• Main Authors: ELLER, DARREN, C, TANNONE, BRETT, E, CONDO, MARK, A, KARACHRISTOS, KOSTA, G, HULSE, JON, MARTIN, DALE, D
• Format: Patent
• Language: English
• Published: 25.11.2011
• Subjects: ACCESSORIES THEREFOR; FIXED CONSTRUCTIONS; HANDCUFFS; KEYS; LOCKS; SAFES; WINDOW OR DOOR FITTINGS

An electronic push-retraction exit device for latching and unlatching a door, the exit device comprising a support rail (10) mountable to the door, a pair of rocker levers (28, 30) mounted on the support rail (10), a push rail (22) mounted on the pair of rocker levers (28, 30), a latch bolt (18) operably connected to the push rail (22) and a linear actuator (40) for controlling the latch bolt (18) and push rail (22). The linear actuator (40) includes a linearly movable shaft connected via a lost motion connection to the pair of rocker levers (28, 30) which allows the push rail (22) to be manually moved to the inward position without moving the shaft of the linear actuator (40), a stepping motor (42) connected to linearly move the shaft when the stepping motor (42) rotates and thereby move the push rail (22) to the inward position to electronically unlatch the door and a control circuit electrically connected to the stepping motor (42). The control circuit is operable to control the stepping motor (42) in three states: a driving state, in which the stepping motor (42) rotates to move the push rail (22) and the latch bolt (18) towards the inward position to electronically unlatch the door; a holding state in which rotation of the stepping motor (42) is prevented and the linear actuator (40) is held at a constant linear position to prevent the push rail (22) from returning to the outward position towards which it is biased; and an off state in which power is removed from the stepping motor (42) to allow rotation of the stepping motor and thereby allow the push rail (22) to return to the biased outward position and latch the door.