Patent ID: 8262444

Claim:
An electronic device comprising: a housing defining an outlet; an active fan installed in the housing; and an airflow reversal prevention assembly fixed in the housing, comprising: a first grid plate defining a plurality of vents; a second grid plate clinging to the first grid plate in parallel, the second grid plate defining a plurality of vents being selectively aligned with the vents of the first grid plate; a passive fan comprising a stator shaft unmovable relative to the first grid plate, and a plurality of vanes rotatably mounted to the stator shaft to be driven to rotate about the stator shaft by air from the active fan; at least one drive member connected between the second grid plate and the vanes of the passive fan, such that the second grid plate is moved with the rotation of the vanes of the passive fan to align the vents of the second grid plate with the vents of the first grid plate; and at least one elastic member to bias the second grid plate to move back to make the vents of the second grid plate being out of alignment with the vents of the first grid plate.