Abstract: A method of installing a ventilation device through existing plywood door closures of accesses to attic spaces with roof fans in homes includes a frame with louvers across a central opening closed by two doors hingeably attached to be opened and closed with a hook rod interconnecting with eye bolts on the doors, the entire device being insulated to reduce heat loss during the cooler seasons.

Abstract: A louvre type roof structure including a plurality of parallel slats mounted on carrier beams extending transversely to the slats, in which the slats are mounted on carrier elements which are in turn mounted on the carrier beams to permit pivotal displacement of the carrier elements and of the slats between a closed position in which they are disposed in a roughly coplanar position, and an open position in which they are disposed in spaced apart parallel planes. The carrier elements are secured to the slats by means of lugs engaging the slats without penetrating the slats. The carrier elements are mounted on the carrier beams by mounting levers, a pair of mounting levers being provided in respect of each carrier element, one of a pair of levers being a fixed lever and being secured to the carrier beam in a fixed position, and the other one being a free lever and being displaceable relative to the carrier beam.

Abstract: The present invention relates to a housing for electrical equipment. The housing is composed of side walls, ventilation openings in the side walls and at least one louver provided in front of the ventilation openings. The housing additionally includes a cover plate which is arranged between the ventilation openings and the louver. The cover plate is inserted into a receptacle at the rear face of the louver. This housing makes it possible to close or open, respectively, existing ventilation openings by means of the cover plates and thus adapt the housing to the respective cooling requirements, whether equipped individually or upon subsequent changes in the equipment.