| 摘要 |
A vacuum cleaning head includes a housing (12) having a suction opening (36) for admitting an air flow to the head, an agitator (60) for agitating a surface to be cleaned, the agitator having an active state and an inactive state, a duct (82) for receiving the air flow from the housing, and a control assembly (174) for controlling the state of the agitator (60). The control assembly (174) includes a pressure chamber (176) having an interior volume in fluid communication with the duct (82) and which is variable between an expanded configuration and a contracted configuration in response to a pressure difference between the interior volume and ambient air, an actuator (172) for effecting a transition of the agitator (60) from one of the active state and the inactive state to the other of the active state and the inactive state in response to a transition of the pressure chamber (176) to the contracted configuration, and a control mechanism (214, 238) having a first state for preventing the pressure chamber (176) from adopting the contracted configuration, and a second state for allowing the pressure chamber (176) to adopt the contracted configuration. The control mechanism (214, 238) is arranged to change between the first and second states in response to an increase in the interior volume of the pressure chamber (176), for example in response to an increase in the air pressure within the duct (82). |
