Air diffuser

DETAILED DESCRIPTION The air diffuser of the invention is preferably made of sheet metal and comprises an upper polygonal plate, preferably having a pair of straight, generally parallel side edges, spaced apart a distance slightly smaller than the standard spacing between a pair of ceiling tile-supporting rails of a conventional suspended ceiling system, so as to be supported by said rails in lieu of a ceiling tile.
Said upper plate has means to form a central hole of a selected size therein for installation of a connecting collar to be secured to an air supply duct.
An air deflector lower plate is suspended from the upper plate in a position spaced from and below the upper plate to provide a peripheral gap of substantially uniform and constant width between the two plates.
The lower plate is substantially co-extensive with the upper plate and is of the same polygonal shape, defining a plurality of substantially straight peripheral edges.
There are as many substantially-rectangular baffle plates as the number of peripheral edges of said lower plate.
Each baffle plate is located in the gap and has a free longitudnal edge and an opposite longitudinal edge which is hinged by hinge means to one of said upper and lower plates.
The hinge axis of each baffle plate is substantially parallel to a related peripheral edge of the lower plate and is located inwardly of said peripheral edge.
Each baffle plate has a width equal or greater than the width of said gap and is angularly adjustable in said gap between a fully-open position substantially parallel to said upper and lower plates, and a fully-closed position in which the free longitudinal edge of said baffle plate rests against the other one of said upper and lower plates.
Preferably, when the baffle plate width is greater than the gap width, the end edges of said baffle plates are inclined with respect to said free longitudinal edges at an angle selected, so that the said end edges of adjacent baffle plates come practically in contact with each other when said baffle plates are in closed position