US Patent 7883123 Electronic push retraction exit device

An electronic push retraction exit device includes a support rail, a push rail and a latch mechanism having a latch bolt operably connected to the push rail and movable between latched and unlatched positions. A control circuit in the exit device drives a linear actuator to retract and hold the push rail and the latch bolt in the unlatched position. The linear actuator preferably includes a stepping motor and is connected to the push rail through a lost motion connection allowing the exit device to be mechanically operated without moving the linear actuator. The control circuit preferably includes an electrical adjustment for the retraction distance of the latch bolt and an adjustable relatch timer. The exit device may be operated by a remote switch attached to a control connection, which may be permanently closed to simulate a prior art electrically operated exit device for compatibility with third party control systems.