Abstract: An autocoupler flange is coupled to a rigid waveguide through a flexible waveguide. The autocoupler flange is supported in a stationary housing by support pins projecting through shaped apertures in the housing and a system of springs to maintain the autocoupler flange in a position skewed to the vertical. The autocoupler flange includes a stop member with a horizontal alignment slot therein. A movable waveguide flange has an alignment bracket secured thereto, the alignment bracket including a horizontal alignment pin. Vertical motion of the movable waveguide flange and alignment bracket engages the autocoupler flange, lifting the autocoupler flange from its support on the stationary housing. The horizontal alignment pin engages the horizontal alignment slot to provide horizontal alignment between the flanges. In the coupled position, the autocoupler flange is supported on the waveguide flange with the system of springs locking the flanges together.