GARAGE DOOR POWER OPERATOR HAVING PARTIAL OPEN CAPABILITY

摘要

An automatic power operator for garage doors having adjustable limit stops including a short screw shaft driven by the operator motor and a pair of traveler nuts on the screw shaft and individually adjustable in linear position to establish up and down limits of travel. The travelers nuts operate in connection with up and down limit switches to shut off power to the drive motor after the predetermined limit of travel has been reached. A "memory" device in the form of a pivotal lever is disposed adjacent the screw shaft and the down limit switch to hold the down limit switch in the open circuit condition until the door is nearly fully opened such that a second actuation of the device following initiation of movement in the upward direction simply causes the operator motor to stop. By this feature any of an infinite number of partially opened door positions can be readily accomplished by the user.