Abstract: A grille (3) for use adjacent an outlet of a heating, ventilating or air conditioning system comprising a frame (15) and a plurality of blades (25) extending between opposed frame parts. Each blade (25) has a spindle (26) which is rotatably supported within opposed slots (21) formed in the opposed parts of the frame. The slots (21) are open at one end to permit the insertion of the blade spindle and the spindle is supported at the closed ends of the slots. The grille (3) further comprises means for retaining the blade spindles (26) in the slots (21). The retaining means comprise an element (30) mountable upon the frame (15) of the grille such that part of the retaining element (30) engages the blade spindles (26) when mounted upon the frame and prevents the spindles (26) from moving out of the open ends of the slots (21).

Abstract: At an outlet of a heating, ventilating or air conditioning system air passes from the ducting through a plenum chamber, a damper provided with a set of blades which are movable between open and closed positions and a diffuser which directs the air in a desired direction. The plenum chamber is provided with internal vanes which act to guide a flow of air through the chamber between its inlet and outlet. The damper defines a plurality of predetermined blade positions between the open and closed positions and a resilient finger and teeth for retaining the blades in a selected one of said predetermined positions. The damper has a frame comprising a plurality of discrete frame elements interconnected at each corner joint of the frame by a friction fit pin passing through interdigitated projections on the frame elements.