Brushing – scrubbing – and general cleaning – Machines – With air blast or suction
Patent
1987-05-04
1990-05-01
Coe, Philip R.
Brushing, scrubbing, and general cleaning
Machines
With air blast or suction
15319, 15412, A47L 928
Patent
active
049206079
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an arrangement in a vacuum cleaner.
In a vacuum cleaner having an electronic speed control, varying of the speed of the vacuum cleaner motor renders it possible to set the suction power within wide limits according to need. Such a setting may take place in an automatic way considering various parameters such as the degree of filling of the dust container of the vacuum clearner and the nature of the surface to be cleaned. The setting can also be made manually by operation of a control means, e.g. a knob located on the vacuum cleaner and connected to a potentiometer.
Often, modern vacuum cleaners are equipped with strong motors rated at 1000 watts or more and these work satisfactory under most conditions. However, there are cases where a temporary increase in the suction power may be needed, e.g. for removed threads and hair stuck in a wall-to-wall carpet. One way would be to provide the vacuum cleaner with a stronger suction unit. However, this solution results in the vacuum cleaner being overpowered for most of the normal cases of operation. In addition to increase in costs at the power rates concerned this overpowering results in increased temperature levels which may involve cooling problems.
The object of the invention is to remedy the disadvantages referred to and to provide a vacuum cleaner in which it is possible to temporarily obtain increased suction power without the need for dimensioning of the vacuum cleaner for continuous output at the enhanced power corresponding to the increased suction power.
The invention will now be described in detail in connection with an embodiment with reference to the enclosed drawings in which
FIG. 1 schematically shows a vacuum cleaner provided with an electronic speed control device.
FIG. 2 is a block diagram of the electric and electronic functional blocks included in the vacuum cleaner.
FIG. 3 is a more detailed wiring diagram of the functional blocks essential for the invention and shown in FIG. 2.
FIG. 1 shows schematically the construction of a common domestic vacuum cleaner. An inlet opening 11 and an outlet opening 12 are provided in a casing 10. A dust container 13 is connected to the inlet opening. For the generation of the suction air stream a suction fan 14 is provided which is driven by an electric motor 15. The motor is controlled by an electronic control device 16. In order to set a motor speed corresponding to the desired suction power, a potentiometer 17 connected to the control device can be operated by a knob 18. Speeds may be selected by the potentiometer within a range limited at its upper end by a speed that corresponds to the maximum power for continuous operation The control device can be operated a push-button switch 19 to increase the motor speed to a level corresponding to a power level exceeding the maximum power for continuous operation.
The higher, exceeding motor power canot be made available for more than a given time without an unallowable rise in temperature levels. Therefore, the higher power output must be limited in time and in the example described the time has been chosen to be 10 seconds. Further, in order to give the motor and the surrounding parts an opportunity to cool the higher power level must not be switched in again until after a predetermined recovery time, in the example 20 seconds.
FIG. 2 is a block-diagram of a circuit which makes it possible to switch the higher power in and out in the way described. For that purpose the electronic control device 16 has two inputs 20,21 and one output 22 which connect the control device to the motor 15. To the input 21 there is connected a device 23 which continuously emits a control signal, in the following referred to as the second control signal, which operates the control device 16 to drive the motor at the speed corresponding to the higher power. The movable contact of the potentiometer 17 is connected to the input 20 while the fixed terminals of the potentiometer are connected via resistors 24,25 to a first input 26 of a logical circuit 27 an
REFERENCES:
patent: 3579706 (1971-05-01), Hetland
patent: 4245370 (1981-01-01), Baker
patent: 4357729 (1982-11-01), Vandermolen et al.
patent: 4370690 (1983-01-01), Baker
patent: 4514874 (1985-05-01), Kurz
patent: 4615070 (1986-10-01), Frederick et al.
Aktiebolaget Electrolux
Coe Philip R.
Reinckens Corinne M.
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