US Patent 7278181 Vacuum cleaner with air bleed

A vacuum cleaner comprises a cyclonic separator (116) for separating dirt and dust from an incoming airflow. A tool (300) and a suction conduit (114) connect the tool (300) to the separator (116). The tool (300) comprises a main air inlet aperture for engaging with a surface to be cleaned and a bleed air inlet (310) for allowing air to bleed into the suction path. The bleed air inlet (310) is located such that it is separate from the main inlet. The cross-sectional area of the bleed air inlet (310) is sufficiently large that, in use, the bleed air inlet (310) admits a sufficient quantity of air to maintain adequate separation efficiency in the separator of the cleaner even when the main air inlet is fully blocked.