Abstract: A battery-operated surface treatment apparatus having a booster function, preferably a vacuum cleaner, comprises an electric motor (10) which drives a treatment unit, such as a suction fan. Further, the apparatus comprises a battery-powered power supply unit (11) for the motor and, in addition, the apparatus is provided with a coupling device (18,23) for the activation of the booster function by temporarily connecting a separate battery (14) in series with the batteries in the power supply unit (11).

Abstract: A portable suction cleaner comprises a housing (10) with a filter bag (11) and a suction fan (12) driven by a motor (13). The suction cleaner is characterized in that the housing (10) is provided with a carrier belt (19) adapted to be applied around the bearer's waist or hips.

Abstract: In a suction cleaner comprising a housing (10) having an inlet (11), a filter chamber (12) with a filter bag (13), a suction fan (14) with a motor (15), and an outlet passage (17) through which filtered air passes from the suction fan to an outet (16), the motor is provided with a control circuit (20) adapted to be activated by a first pressure switch (21) which is actuated by the underpressure in the filter chamber (12) in order to control the motor power at a predetermined level. According to the invention, the suction cleaner is provided with a second pressure switch (22) which is actuated by the pressure in the outlet (17) and adapted to activate the control circuit (20) when said pressure exceeds a predetermined level.

Abstract: In a suction cleaner comprising a housing (10) with a disposable filter bag (13) a movable tube piece (17) is provided which is adapted to enter the inlet opening (14a) of the filter bag. According to the invention, the tube piece (17) is provided with a control means actuatable by a pressure difference, preferably the difference between atmospheric pressure and the underpressure in the suction cleaner housing.