Patent ID: 6836930

Claim:
An airflow indicator for a vacuum cleaner, comprising: a housing mounted to a casing of the vacuum cleaner; a piston chamber defined within the housing; a piston received in the piston chamber and movable therein between a first position and a second position; a first port formed in the housing and communicating with the piston chamber, the first port being open to ambient; a second port formed in the housing and communicating with the piston chamber, the second port being spaced from the first port and being open to a filter chamber of the vacuum cleaner; and a valve mounted to the housing in one of the first port, the second port and the piston chamber for obstructing air passage into the piston chamber from one of the first port and the second port, the valve including a diaphragm having a slit that opens in response to a predetermined pressure differential between the first port and the second port.