Disposable filter bag

Claim 1

A DUST RECEPTACLE FOR A VACUUM CLEANING DEVICE COMPRISING A BAG-LIKE ENCLOSURE FORMED OF A FILTERING MATERIAL, SAID ENCLOSURE BEING DEFINED BY OPPOSING SIDE WALLS AND AT LEAST ONE END FACE WALL, AN INLET AIR FLOW APERTURE DEFINED IN SAID END WALL, SUCTION RESPONSIVE VALVE MEANS PROVIDED IN SAID END WALL FOR NORMALLY CLOSING SAID APERTURE IN THE ABSENCE OF SUCTION PRESSURE WITHIN SAID ENCLOSURE AND FOR OPENING SAID APERTURE IN RESPONSE TO SAID SUCTION PRESSURE, SAID VALVE MEANS COMPRISING A PAIR OF OPPOSITELY EXTENDING OVERLAPPING FLEXIBLE FINGERS INTEGRALLY FORMED IN SAID END WALL AND FLEXIBLE INTO SAID ENCLOSURE IN RESPONSE TO SUCTION PRESSURE THEREIN, AN ELONGATED SLOT DEFINED IN ONE OF SAID SIDE WALLS, AND A TRANSPARENT FLEXIBLE PLASTIC STRIP SECURED TO THE INNER SURFACE OF SAID ONE SIDE WALL, SAID STRIP UNDERLYING SAID SLOT TO DEFINE A WINDOW IN SAID ONE SIDE WALL, ONE END OF SAID STRIP EXTENDING FROM SAID ONE SIDE WALL TO SAID END FACE WALL AND BEING SECURED TO THE INNER SURFACE OF ONE OF SAID FLEXIBLE FINGERS TO FORM HINGE MEANS FOR URGING SAID ONE FINGER TO CLOSED POSITION AND BIAS THE LATTER IN RESPONSE TO SAID FLEXING THEREOF.