2153014-A is referenced by 3 patents and cites 3 patents.

An air ventilator for ventilating indoor air to the environment is constructed so that when the motor 3 is operating, the centrifugal weight members 15 cause the rotatable circular plate (6), to displace angularly, the displacement being transmitted to the fan blades (10) for ventilating the inside air to the environment. When the motor is not operating the centrifugal weight members (15) return to their original position under the action of the torsion coil springs, thereby closing the air-passages between the fan blades and acting as shutters.

Title
Automatically shuttered ventilator
Application Number
GB19840030269 19841130
Publication Number
2153014 (A)
Application Date
November 30, 1984
Publication Date
August 14, 1985
Inventor
Yoo Byung Eun
Assignee
Yoo Byung Eun
IPC
F04D 29/36
F04D 25/14
F24F 07/013
F04D 29/32
F04D 25/02
F24F 07/013
F04D 29/36
F04D 25/14
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