Patent ID: 8607408

Claim:
A vacuum cleaner comprising a closure element which: is biased towards a position in which the closure element acts to retain accumulated particulate matter within the cleaner; and which is influenced by the weight of accumulated particulate matter to move to a position in which the closure element does not act to retain accumulated particulate matter within the cleaner; and in which the closure element is a flap on which at least a portion of the particulate matter accumulates; and further comprising a housing and in which: the flap further comprises a counterweight; and the flap is hingedly mounted to the housing to allow movement of the flap between: the position in which the closure element acts to retain accumulated particulate matter within the cleaner and the position in which the closure element does not act to retain accumulated particulate matter within the cleaner; and in which the housing comprises an open-ended frusto-conical portion and the flap acts to retain accumulated particulate matter within the cleaner by substantially occluding the open end of the frusto-conical portion of the housing; and in which centripetal forces on air-entrained particulate matter as it moves around the inner surface of the open-ended frusto-conical portion influence that particulate matter to accumulate on the flap.