Ventilating air diffuser apparatus

Claim 1

AN AIR DIFFUSER COMPRISING A PERFORATED MAIN AIR DIFFUSER PANEL HAVING DIVERGING PERFORATED SIDE WALLS, SIDE LONGITUDINAL FLANGES AND END WALLS, A SUBSTANTIALLY FLAT SLOTTED AIR FLOW CONTROL PANEL SECURED TO SAID FLANGES AND OPPOSING SAID MAIN AIR DIFFUSER PANEL AND FORMING THEREWITH AN AIR CHAMBER, A SUBSTANTIALLY FLAT SLIDING SLOTTED VALVE PLATE ON THE OUTER FACE OF THE CONTROL PANEL AND HAVING CONSTRAINED GUIDED MOVEMENT WITH THE CONTROL PANEL AND SAID FLANGES AND MOVABLE IN OPPOSITE DIRECTIONS LONGITUDINALLY OF THE CONTROL PANEL SO THAT THE DEGREE OF REGISTRY OF SLOTS IN THE CONTROL PANEL AND VALVE PLATE MAY BE VARIED FROM FULLY REGISTERED TO NON-REGISTERED, THERE BEING NO OBSTRUCTING ELEMENTS PROJECTING OUTWARDLY OF THE VALVE PLATE SO THAT THE SIDE OF THE AIR DIFFUSER OPPSOITE THE MAIN AIR DIFFUSER PANEL IS SUBSTANTIALLY FLAT, A SCREW-THREADED PART ON THE VALVE PLATE WITHIN SAID CHAMBER, A LEAD SCREW ON ONE OF SAID END WALLS HAVING SCREW-THREADED ENGAGEMENT WITH SAID PART, THE LEAD SCREW INCLUDING A PORTION HAVING OPPOSITE HAND SCREW THREADS, AND A PART ON SAID END WALL HAVING SCREW THREADS ENGAGING SAID OPPOSITE HAND PORTION.