LIMIT SWITCH ARRANGEMENT FOR GARAGE DOOR OPERATOR

摘要

A door operator for a reversibly operable door includes a frame and a carriage movably mounted on the frame and attached to a door for moving the door between open and closed positions. A drive member, specifically a roller chain, extends along the frame and moves the carriage. A drive train is provided within a housing and is connected for moving the drive member, and a control circuit is provided for controlling the drive train to open and close the door. A pair of limit switches is mounted within the housing and connected to the control circuit for stopping the drive train when the door has reached a completed position. A pair of limit cams are adjustably mounted on a limit wheel within the housing and separate from the carriage for engaging the limit switches. The limit wheel, which is separate from the drive member, is connected to the drive train to rotate when the drive train moves the carriage. The placement of limit switches and associated connecting wiring along the frame in the garage ceiling is eliminated. The limit cams can be easily and automatically positioned on the limit wheel by pushing a single switch without any manual movement of the limit switches or of the movable cams that contact the limit switches.