Patent attributes
A door for an arc-resistant compartment includes an opening there-through. Flap structure includes a flap member coupled to the door and movable between an opened position permitting air to pass through the opening, and a closed position covering the opening. Spring structure is engaged with the flap member to bias the flap member to the closed position. Handle structure is coupled to the flap member and extends through the door for moving the flap member to the opened position against the bias of the spring structure. Retaining structure provides a retaining force on the flap member to retain the flap member in the open position, against the bias of the spring structure. During an arcing event in the compartment, pressure within the compartment together with the bias of the spring structure overcomes the retaining force to automatically move the flap member to the closed position.