Safety gate operator which prevents entrapment, and method of its

Abstract

An automatic gate operator includes an electric drive motor coupled by a drive train to a movable gate, and includes provisions for sensing an actual or impending obstruction or blockage of the movement of the gate by a human, object, or animal, for example. In response to such an actual or impending blocking of the gate's movement, the drive motor is shut off and the gate is braked to a stop. Then the gate is reversed to move a short distance away from the actual or impending blockage or obstruction, and is braked again to a stop. Next, the gate is freed from its connection with the drive motor, allowing manual movement of the gate to allow clearance of the actual or impending blockage or obstruction from the path of the gate. This stop-reverse-stop-release sequence of movements for the gate may release any entrapped person or object which may have been contacted by the moving gate. Also, after the gate is released for free movement it can be moved manually. This release of the gate allows an entangled person, object, or animal to free themselves, or to be freed by a bystander, for example. The gate operator also includes a control circuit which senses traffic conditions and responds by incrementing or decrementing a timer which controls a pause interval of the gate in its fully-opened position.