Device for signalling need for cleaning or replacing suction cleaner dust bag

Claim 1

IN A SUCTION CLEANER OF THE CLASS DESCRIBED HAVING A CASING PROVIDED WITH AN INLET AND OUTLET FOR AIR ADAPTED TO FLOW THERETHROUGH AND A DUST BAG THEREIN FOR REMOVING DIRT FROM THE AIR, THE PRESSURE DIFFERENTIAL AT OPPOSITE SIDES OF SAID DUST BAG BECOMING INCREASINGLY GREATER RESPONSIVE TO DIRT TRAPPED AT THE DSIDE THEREOF INITIALLY CONTACTED BY THE AIR, THE COMBINATION OF A DEVICE FOR INDICATING THE NEED FOR CLEANING OR REPLACING THE DUST BAG DUE TO DIRT TRAPPED THEREIN, SAID DEVICE PRODUCING SUCH INDICATION WITH THE AID OF AIR AND INCLUDING A MEMBER WHICH HAS A PASSAGEWAY THEREIN AND DEFINES A VALVE SEAT, VALVE MEANS MOVABLE TOWARD AND FROM SAID SEAT FOR CONTROLLING FLOW OF AIR FOR OPERATING SAID DEVICE, MEANS RESPONSIVE TO A PRESSURE DIFFERENTIAL AT OPPOSITE SIDES OF SAID DUST BAG TO MOVE SAID VALVE MEANS FROM SAID SEAT FOR EFFECTING FLOW OF AIR THROUGH SAID PASSAGEWAY TO RENDER SAID DEVICE OPERABLE TO PRODUCE SAID INDICATION, MEANS FOR MOUNTING SAID MEMBER FOR MOVEMENT IN A PATH OF MOVEMENT TOWARD AND FROM SAID VALVE MEANS TO SHIFT THE POSITION OF SAID VALVE SEAT WITH RESPECT TO SAID VALVE MEANS, AND MEANS ACCESSIBLE AT THE INTERIOR OF SAID CASING FOR MANUALLY MOVING SAID MEMBER TOWARD AND FROM SAID VALVE MEAN TO ADJUST THE POSITION OF SAID VALVE SEAT IN SAID PATH OF MOVEMENT AND REGULATE THE PRESSURE DIFFERENTIAL AT OPPOSITE SIDES OF SAID DUST BAG AT WHICH SAID DEVICE IS RENDERED OPERABLE TO PRODUCE SAID INDICATION.