US Patent 8480136 Exit device and method of operating the same

An exit device that includes a locking mechanism for locking and unlocking a door, the locking mechanism having a latch bolt, and a link connected to the latch bolt, movement of the link between locked and unlocked positions causes movement of the latch bolt between an extended state and a retracted state to lock and unlock the door, and a motor operably connected to the link. A method of operating the exit device includes operating the motor to move the link in a first direction toward the unlocked position, the motor being operated until the link reaches a hard stop position; thereafter determining a soft stop position based on the hard stop position; and thereafter selectively using the motor to move the link in the first direction toward the unlocked position, the motor being operated only until the link reaches the soft stop position.