Vacuum cleaner brush roll control device

Abstract

A vacuum cleaner including a brush roll, a motion sensor assembly that detects motion of the vacuum cleaner and that generates signals indicative of the detected motion, and a brush roll control unit that controls operation of the brush roll based on the signals generated by the motion sensor assembly.

Description

FIELD OF THE INVENTION

The present disclosure relates to vacuum cleaners and, more particularly, to a vacuum cleaner having a brush roll that is automatically switched on and off during operation of the vacuum cleaner.

BACKGROUND OF THE INVENTION

Conventional vacuum cleaners typically include a brush roll disposed in the vacuum cleaner nozzle head that rotates in contact with the surface to be cleaned to agitate and loosen ingrained dirt particles so that the dirt particles can be more easily sucked up by the vacuum. When a vacuum cleaner has a driven brush roll, such as a brush roll driven by a motor or an air forced brush roll, it is important for the user to constantly move the nozzle head across a carpet. If the user holds the nozzle head stationary without lifting the nozzle head, raising the brush roll off the carpet or turning off the brush roll, the spinning brush roll will apply excessive wear and tear on the carpet, as well as on the bristles on the brush roll, itself. This is particularly troublesome when the user is distracted, such as when the user needs to pick up an object that is in the way of the vacuum, and walks away from the vacuum cleaner while the brush roll is still being driven in place.

There are known brush roll control devices that automatically shut off the brush roll when the handle is disposed in the upright position. However, these control systems are not particularly effective, since the user must remember to place the handle in the upright position when the nozzle head is held stationary to ensure that the brush roll is inactivated. Other systems use a switch that is activated to turn off the brush roll when a vacuum wand is removed from the vacuum cleaner housing for above-the-floor cleaning. However, when above-the-floor cleaning is not being performed, the user must once again remember to turn off the brush roll when the nozzle head is held stationary. Further, some vacuum cleaners simply do not allow the user to switch on and off the brush roll while the vacuum in being operated.

Accordingly, there is a need for a brush roll control system that prevents the brush roll from spinning when the nozzle head is held stationary, without the user having to perform a particular function, such as placing the vacuum cleaner handle in the upright position or manipulating a switch that deactivates the brush roll.

SUMMARY OF THE INVENTION

A vacuum cleaner according to an exemplary embodiment of the present invention includes a brush roll, a motion sensor assembly that detects motion of the vacuum cleaner and that generates signals indicative of the detected motion, and a brush roll control unit that controls operation of the brush roll based on the signals generated by the motion sensor assembly.

In at least one embodiment, the vacuum cleaner includes at least one wheel disposed in contact with a surface to be cleaned, and the motion sensor assembly detects motion of the vacuum cleaner based on rotation of the at least one wheel.

In at least one embodiment, the motion sensor assembly includes a plurality of detectable indexes disposed around a circumference of the at least one wheel, and a sensor disposed adjacent to the at least one wheel, where the sensor generates the signals based on location of the plurality of magnetic elements relative to the sensor.

In at least one embodiment, the vacuum cleaner further includes a brush roll drive motor that drives the brush roll, and the control unit includes circuitry that generates and sends control signals to the brush roll drive motor based on the signals generated by the motion sensor assembly to control operation of the brush roll.

A method of automatically controlling operation of a brush roll of a vacuum cleaner according to an exemplary embodiment of the present invention includes sensing whether the vacuum cleaner is in motion using a motion sensor assembly, stopping operation of the brush roll when the vacuum cleaner is sensed as being stationary, and starting or maintaining operation of the brush roll when the vacuum cleaner is sensed as being in motion.

In at least one embodiment, the method further includes delaying the step of stopping operation of the brush roll for a predetermined period of time after the vacuum cleaner is sensed as being stationary

These and other features of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of this invention.

BRIEF DESCRIPTION OF THE FIGURES

Various exemplary embodiments of the invention will be described in detail, with reference to the following figures, wherein:

FIG. 1 is a perspective view of a vacuum cleaner according to an exemplary embodiment of the present invention;

FIG. 2 is a detailed perspective view of the vacuum cleaner of FIG. 1 showing internal components of the vacuum cleaner nozzle head; and

FIG. 3 is a circuit diagram of the control circuitry within the control device of the vacuum cleaner of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The various exemplary embodiment of the present invention are directed to a vacuum cleaner that includes a motion detector that is used to activate and deactivate a brush roll disposed within the vacuum cleaner nozzle head. When the vacuum is detected as being in motion, motion detecting logic is used to keep the brush roll running or to initially activate the brush roll. When the vacuum is detected as being stationary, the motion detecting logic is used to deactivate the brush roll. Preferably, the deactivation of the brush roll is delayed for a brief period of time after the vacuum cleaner is detected to be stationary, and the activation of the brush roll is immediate after motion is detected. However, the present invention is not meant to be limited to this embodiment and, alternatively, motion control logic may be used that results in any variation of delayed and immediate activation and deactivation of the brush roll. Further, although the embodiment of the present invention disclosed herein is directed to an upright vacuum cleaner, it should be appreciated that the present invention is not meant to be limited to any particular vacuum cleaner type.

FIG. 1 shows a vacuum cleaner, generally designated by reference number 1, according to an exemplary embodiment of the present invention. The vacuum cleaner 1 includes a handle portion 10 attached to a vacuum cleaner nozzle head 20. The handle portion 10 may include a housing 12 for storage of a vacuum hose 14, that can be removed from the housing 12 and attached to a wand (not shown) for above-the-floor cleaning. The handle portion 10 may be pivotally attached to the nozzle head 20 so that the handle portion 10 can be locked in an upright storage position and unlocked and maneuverable relative to the nozzle head 20 when the vacuum is in use. The nozzle head 20 may include a pair of wheels 22, one on each side of the nozzle head 20.

FIG. 2 is an internal view showing various components held within the nozzle head 20. A brush roll 40 is disposed within the nozzle head 20. The brush roll 40 is driven by a brush roll drive motor 50 via a brush roll drive belt 48. The brush roll 40 preferably includes strips of bristles 42 that assist in removing dirt from a carpet pile as the brush roll 40 is rotated by the brush roll drive motor 50.

A motion sensor assembly, generally designated by reference number 24, is disposed adjacent to one of the wheels 22. The motion sensor assembly 24 includes a number of detectable indexes 26 disposed equally spaced around the inner circumference of the wheel 22 and a stationary motion detector 28 disposed adjacent to the wheel 22, so that the indexes 26 are consecutively aligned in face-to-face relation to the motion detector 28 as the wheel 22 rotates. The indexes 26 may be, for example, magnetic disks. The motion detector 28 is preferably a Hall-effect sensor element. In other embodiments of the invention, the motion sensor assembly 24 may include alternative sensor components, such as, for example, a brush-contact switch, a magnetic reed switch, an optical switch, or a mechanical switch. Also, depending on the type of motion detector used, the indexes 26 may be gaps, notches, or contacts, or the indexes 26 may be replaced with a single element, such as, for example, a cam lobe. In general, the present invention is not meant to be limited to a particular type of motion detector assembly, and any known or later discovered motion detector is suitable for use with the present invention.

The motion sensor assembly 24 is electrically connected to a control unit 30. The control unit 30 receives signals from the motion sensor assembly 24, and based on the signals controls the operation of the brush roll drive motor 50. As explained in further detail below, the control unit 30 may include circuitry that controls the brush roll drive motor 50 such that the brush roll 40 is driven by the drive motor 50 when the vacuum wheels 22 are in motion and the brush roll 40 is not driven by the drive motor 50 when the vacuum wheels 22 are stationary.

FIG. 3 shows the circuitry, generally designated by reference number 60, of the control unit 30 according to an exemplary embodiment of the invention. The circuit 60 requires the motion detector 28 to pull low or short to ground when a magnetic element 26 is detected. The motion detector 28 is represented as a Hall-effect switch U1 in the circuit 60. In other embodiment of the invention, the Hall-effect switch U1 could be replaced with a mechanical switch that repeatedly opens and closes a contact to ground (logic 0) as the wheel moves. The circuit 60 further includes a discrete logic Exclusive OR (XOR) gate U2. An XOR gate has two inputs Pin 1 and Pin 2 and one output Pin 3. The output at Pin 3 is true or logic 1 if both inputs at Pin 1 and Pin 2 are different, and is false or logic 0 when both inputs at Pin 1 and Pin 2 are the same (either both high or both low). A resistor R1 serves to provide a logic 1 (+5 V) when the switch U1 is open. When the switch U1 is closed, a logic 0 (0 V) is provided. The logic output from the switch U1 is fed directly to Pin 1 of the XOR gate, and also fed to Pin 2 of the XOR gate through resistor R2 with capacitor C1 going to ground.

Because it takes time for capacitor C1 to charge or discharge through R2, the voltage on Pin 2 of the XOR gate is delayed for a few milliseconds. The previous logic state of the switch U1 is thus stored in capacitor C1 for a short period of time. Whenever the switch U1 changes from high to low, Pin 1 of the XOR gate immediately goes low but Pin 2 remains high and begins to go low as capacitor C1 discharges through R2. For the short period of time when Pin 2 is high and Pin 1 is low, the output at Pin 3 of the XOR gate goes high briefly until Pin 2 goes low. Similarly, if the switch U1 changes from low to high, Pin 1 of the XOR gate immediately goes high but Pin 2 remains low and begins to go high as capacitor C1 charges through R1 and R2. Again, for the short period of time when Pin 2 is low and Pin 1 is high, the output at Pin 3 of the XOR gate goes high but returns low as capacitor C1 charges and provides logic 1 on Pin 2.

The output at Pin 3 of the XOR gate momentarily pulses from low to high each time the switch U1 either opens or closes. The output of the XOR gate could be used to reset a digital timer, or to reset a timing circuit as shown in the right-hand portion of the circuit 60. Whenever the output of the XOR gate goes high, capacitor C2 is quickly charged up to about 4 volts through diode D1. Diode D1 only conducts when the output of the XOR gate is high but does not conduct if the capacitor is charged and the output of the XOR gate is low. Resistor R3 serves to discharge capacitor C2 very slowly. For example, capacitor C2 may discharge from 4 volts to 1 volt in about 2 seconds. Using a higher capacitance in C2 will provide a longer delay, so that 16 uF will provide about 4.5 seconds to discharge and 50 uF would take over 14 seconds to discharge. Comparator U3 has a reference voltage of +1 volt connected to Pin 2. This reference voltage could come from a voltage divider or other source. Whenever the voltage at Pin 3 of the comparator U3 is higher than the voltage on Pin 2, the output at Pin 1 will go high signaling to turn on the brush roll drive motor 50. If the voltage on Pin 3 of the comparator U3 is less than the voltage on Pin 2 of U3, the output at Pin 3 of the comparator U3 will go low signaling to turn off the brush roll drive motor 50. Resistor R3 and capacitor C2 form an RC timer circuit. The status of the timer is the output of comparator U3 which checks the charge voltage on capacitor C2. Thus, whenever the charge on C2 is greater than 1 volt (the reference voltage) wheel motion was detected recently and the brush roll drive motor 50 can remain on. If the charge on capacitor C2 is less than 1 volt, wheel motion was not detected recently and the brush roll drive motor 50 should be turned off.

Alternatively, the XOR gate function or transitions from one logic state to the other may be sensed using a microcontroller. The microcontroller can check the logic state at the junction of R1 and R2 frequently and a free-running counting-timer can be reset each time the switch U1 changes from high to low or from low to high. If the timer reaches a predetermined terminal count (i.e. a predetermined-amount of time passes without any movement of the wheels 22), the brush roll drive motor 50 is turned off. The brush roll drive motor 50 may be turned on when the timer is reset or has not reached the terminal count.

It should be appreciated that, in other embodiments of the present invention, the motor on/off signal does not need to directly control the brush roll motor. Instead, the signal could merely be a control input that is combined with other signal inputs that indicate other conditions that may supersede the motor on/off signal. For example, a malfunction, such as a jammed roller or broken belt, may be detected, in which case a signal indicating the malfunction may be generated that supersedes any motor on signal generated by the brush roll control device.

While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by one skilled in the art from a reading of the disclosure that various changes in form and detail can be made without departing from the true scope of the invention in the appended claims.

Claims

1. A vacuum cleaner comprising:

a brush roll;

a motion sensor assembly that detects motion of the vacuum cleaner and that generates signals indicative of the detected motion; and

a brush roll control unit that controls operation of the brush roll based on the signals generated by the motion sensor assembly.

2. The vacuum cleaner of claim 1, further comprising at least one wheel disposed in contact with a surface to be cleaned, the motion sensor assembly detecting motion of the vacuum cleaner based on rotation of the at least one wheel.

3. The vacuum cleaner of claim 2, wherein the motion sensor assembly comprises:

a plurality of detectable indexes disposed around a circumference of the at least one wheel; and

a sensor disposed adjacent to the at least one wheel, the sensor generating the signals based on location of the plurality of magnetic elements relative to the sensor.

4. The vacuum cleaner of claim 3, wherein the indexes are magnetic elements.

5. The vacuum cleaner of claim 4, wherein the sensor is a Hall-effect sensor.

6. The vacuum cleaner of claim 1, wherein the vacuum cleaner further comprises a brush roll drive motor that drives the brush roll, and the control unit comprises circuitry that generates and sends control signals to the brush roll drive motor based on the signals generated by the motion sensor assembly to control operation of the brush roll.

7. A method of automatically controlling operation of a brush roll of a vacuum cleaner, comprising:

sensing whether the vacuum cleaner is in motion using a motion sensor assembly;

stopping operation of the brush roll when the vacuum cleaner is sensed as being stationary; and

starting or maintaining operation of the brush roll when the vacuum cleaner is sensed as being in motion.

8. The method of claim 7, wherein the vacuum cleaner further comprises a brush roll drive motor, and the step of stopping operation of the brush roll comprises stopping operation of the brush roll drive motor and the step of starting or maintaining operation of the brush roll comprises starting or maintaining operation of the brush roll drive motor.

9. The method of claim 7, further comprising:

delaying the step of stopping operation of the brush roll for a predetermined period of time after the vacuum cleaner is sensed as being stationary.

10. The method of claim 7, further comprising:

delaying the step of starting the operation of the brush roll for a predetermined period of time after the vacuum cleaner is sensed as being in motion.

11. The method of claim 7, wherein the vacuum cleaner further comprises at least one wheel disposed in contact with a surface to be cleaned, and the step of sensing comprises determining whether the at least one wheel is in rotation.