MXPA04011454A - Floor care apparatus with multiple agitator speeds and constant suction power - Google Patents

Abstract

A floor care apparatus has a nozzle assembly housing an agitator. A motor couples to the agitator to drive it at two or more speeds and constant suction power. A user indicates their mode-of-operation preference by positioning a switch. An agitator motor control circuit, responsive to the switch, effectuates motor control by supplying either a fixed duty cycle signal or a substantially constant voltage signal. The fixed duty cycle signal includes a waveform with a substantially constant voltage value that is on for a first or first and second of four quarters of the waveform period. Thereafter, it repeats for additional periods. The switch preferably embodies a resistor network and a fixed current source that creates a voltage input to an A/D converter that falls within a specified range. Other apparatus embodiments contemplate multiple agitators with one or more agitator motors. A suction fan motor, separate from the agitator motor(s), may also exist.

Description

APPARATUS FOR CARE OF FLOORS, WITH MULTIPLE SPEEDS OF AGITATOR AND CONSTANT SUCTION POWER Technical Field The invention relates generally to the floor care field. More particularly, it relates to a floor care apparatus, such as a vertical or basket vacuum cleaner, having a stirrer displaced by a plurality of operating speeds and without corresponding loss of power. Background of the Invention Whether it is basket vacuums or vertical vacuums in all designs and permutations, they have become increasingly popular over the years. In general, vacuum cleaners incorporate a suction fan motor, accompanying filter bag or dust chamber, and a nozzle assembly that is fluidly and mechanically connected to suck dirt and dust through the operator's movement through a vacuum cleaner. floor loaded with dirt. Specifically, a stirrer within the nozzle assembly rotates to strike the hair of a mat and to spread grime and dust for a time when an operator manipulates the cleaner in both directions. Problematically, when operators clean bare floors or Berber or Berber style floor mats, for example, agitators that turn at speed incomplete can sometimes cause damage. In this way, some attempts in the prior art have reduced the suction speed of the fan motor to cause a corresponding reduction in the speed of the agitator. With this, however, there is a corresponding loss in suction and loss of cleaning capacity. In aci erdo with this, the articles for the care of floor ?; they need a stirrer that can rotate without damaging certain types of floor or mat while still providing effective cleaning. COMPENDIUM OF THE INVENTION In accordance with the purposes of the present invention as described herein, an improved floor care apparatus is provided. The appliance can take the form of a basket or vertical vacuum or can incorporate a cleaning device by extracciór or another product developed later that has an agitator. In one embodiment, the floor care apparatus has a nozzle assembly housing an agitator. The motor is coupled to the agitator to move it to two or more speeds, while a user indicates his mode-of-operation preference, in turn indicating a speed preference when placing a switch. A control circuit for agitator motor in response to the commutator, performs motor control by supplying either a fixed duty cycle signal or a substantially constant voltage signal to the motor. In one aspect, the fixed service cycle is approximately 0.25 which corresponds to a rectangular waveform with a substantially constant voltage value that is turned on by the first four fourths of the waveform period. Subsequently, the waveform is repeated for additional periods. In this way, if the line voltage is 120 VAC, the agitator motor receives an average voltage value (in equivalent CD downstream of a bridge rectifier) of 0.25 x 120 or approximately 30 V. In another aspect, the service cycle fixed is approximately 0.5, which corresponds to a rectangular waveform with a substantially constant voltage value that is turned on by the first two fourths of four quarters of the waveform period. Subsequently, the waveform is repeated for additional periods. When the signal is a constant voltage value signal, the agitator motor control circuit produces an agitator motor voltage that corresponds to approximately 100% of the line voltage (again, the agitator motor receives this as DC current equivalent below). of a rectifier bridge). As a result, the agitator is already operated at 100% of the line voltage or approximately 25% or 50% of the line voltage to improve cleaning in various floor styles. During 100% of the line voltage, or full speed, the agitator rotates at approximately 3000 to approximately 6000 rpm. During other times, it rotates to -about 800 to approximately 2000 rpm. A control circuit for agitator motor uses a bridge rectifier, a synchronization circuit - a MOSFET as a transistor switch. If the synchronizer output turns the gate of the MOSFET on or off in this way, pressing or not; B1 agitator motor connected between a power source and the MOSFET source. The bridge rectifier transforms the line voltage into a DC voltage that serves as the power source. A preferred multi-position switch, operated by a user, includes a resistor network and a fixed current source that creates a voxing limitation to an A / D converter that falls within a specified voltage range established by the manufacturer A / D . - • In other modes, vacuum cleaners have multiple agitators with one or more agitator motors that control your speed. Some modalities include rotating or rotating agitators with the same speed, in the same direction, same speed, different directions; different speeds, same direction; or different speeds, different directions n ~, A "motor-suction fan, MFñN, separate from the agitator or motors, MAG, may also exist in the vacuum." Agitator motors may or may not receive inside the agitator. The following description will illustrate and describe the possible modes of the invention, simply by way of illustration of one of the most suitable modes for carrying out the invention, as will be appreciated, the invention is capable of other modalities. Different, and their various details are capable of modification in various obvious aspects, all without departing from the invention.According to this, the drawings and descriptions will be considered as illustrative in nature and not restrictive BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings incorporated in and forming a part "of the specification, illustrate several aspects- of the present invention, and in conjunction with the description, sir / en for ex apply the principles of the invention. In the drawings: Figure 1 is a perspective view of a floor care apparatus, in this instance, a vertical vacuum, constructed in accordance with the teachings of the present invention; Figure 2 is a perspective view-of -a floor care appliance in this instance a basket vacuum cleaner, constructed in accordance with the teachings of the present invention; Figure 3 is a circuit diagram of a modality of a circuit for agitator motor control of. according to the present invention; Figure 4A is a graphical diagram of a substantially constant voltage signal for an agitator motor; The Ficura 4B is a graphic diagram of a cycle signal d < fixed service for an agitator motor; Figure 5 is a more detailed circuit diagram of the agitator motor control circuit of the Figure 3; Figure 6 is a planar diagram of a commutator operated by a representative user to indicate a mode-of-operation preference, thus indicating a speed preference of the agitator; 'Figure 7 is a circuit diagram of a floor care apparatus, which has separate agitator and fan motors; Fig. 8A is a diagram of an alternate embodiment of the present invention having a plurality of agitators, each having a separate agitator-shaker; Figure 8B is a diagram of an alternate embodiment of the present invention, having a plurality of bifurcated agitators; Figure 9 is a circuit diagram of a representative embodiment of a circuit for agitator motor control, for use with a multiple agitator mode; Figure 10 is a circuit diagram of a user-operated switch, to indicate a mode-of-operation preference, thus indicating a speed preference of an agitator motor; and Figure 11 is a cross-sectional view of a stirrer, in accordance with the present invention, housing an agitator motor. Reference will now be made in detail to the present invention, an example of which is illustrated in the accompanying drawings. > DETAILED DESCRIPTION OF THE INVENTION Reference is now made to Figure 1, which shows a floor care apparatus of the present invention. AND.'. illustrated apparatus exemplifies a vertical vacuum 10 which generally comprises a "housing 14", comprising the nozzle assembly 16 and the basket assembly 18. The basket assembly 18 further includes the handle 20 and the handle holder 22. The handle or handle 22 carries a control switch 24 for turning on and off the vacuum 10 e "indicating a user mode-of-operation preference, in this way i idicando a preference of agitator speed, as will be described below. Of course, electric power is supplied to the vacuum cleaner 10 of a standard electrical wall outlet through a cable and plug assembly 17. In the lower portion of the basket assembly 18, rear wheels (not shown) are provided to support the weight of the vacuum cleaner 10. A second set of wheels (not shown) allows the operator to raise and lower the nozzle assembly 16, through selective manipulations of the switch for height adjustment 28. This mechanism for height adjustment is illustrated and described in detail in the US patent No. 5,467,502 issued to Johnson et al., And property of the assignee of the present invention. The description This patent is incorporated herein by reference. To allow convenient storage of the vacuum cleaner 10, a pedal lock 30 functions to lock the basket assembly 18 in a vertical position, as illustrated in Figure 1. When the pedal lock 30 is released, the basket assembly 18 can be pivoted relative to the nozzle assembly 16 as the vacuum cleaner 10 is manipulated to clean the floor. The basket assembly 18 also carries a ' inner chamber.-2 housing a suction fan motor 33 (ie, a motor fan combination of the state of the art). And a dust bag 34 to remove dirt or dust trapped in the air stream as it passes in an air flow path from the nozzle assembly 16 to the suction fan motor. During use, the suction fan motor 33 creates the suction air flow in a well-known manner. Alternatively, manufacturers can substitute a dirt chamber without a filter, a chamber for cyclone dirt or another one for the dust bag. The canister assembly 18 can also carry a final filtration cartridge 42 to trap small particles and prevent their re-introduction into the environment through the discharge gate 44.

The nozzle assembly 16 includes a nozzle and a stirrer cavity 36 which houses a stirrer 38. The agitator 38 shown is rotatably moved by a motor 40 and a cooperating gear driver housed in the agitator (see Figure 11). assembly-described, in more detail in the US patent application co-pending serial number 10 / 380,604, filed on September 10, 2003 with the title "Airflow System for Bagless Vacuum Cleaner" (which is a 371 of PCT / US01 / 30910 filed in October 3, 2001 claiming priority of the US provisional patent application Serial No. 60 / 237,832 filed October 3, 2000), the entire description of which is incorporated herein by reference. In the vacuum cleaner; illustrated 10, the scrubbing action of the rotating agitator brush 38 and the negative air pressure created by the suction fan motor 33, cooperate to brush and pull down the dirt and dust of the carpet hair that is cleaned and then direct the air charged with dirt and dust from the agitator cavity 36 to the powder bag 34. Specifically, air charged with dirt and dust passes serially through a suction inlet and hose (not shown) and / or a duct integrally molded in the nozzle assembly 16 and / or basket assembly 18 as is known in technique. Next, the chamber 32 is supplied and passes through the porous walls of the powder bag 34. The bag 34 serves to trap the suspended dirt, dust and other particles to the interior, while allowing "*" to the "air". -r-now cleanly pass through its wall and then through the suction fan motor 33, the final filtration cartridge 42 and finally to the environment through the exhaust gate 44. With reference to Figure 2, a floor care apparatus of the present invention in this embodiment exemplifies a basket vacuum 210 comprising in genural a base assembly 212 and a nozzle assembly 214. Although not illustrated, the base assembly contains a fan mot suction cooperating with an agitator 16 in the nozzle assembly to suck off dirt and dust in a previously described manner A rod 218 mechanically and fluidly connects to the nozzle assembly and facilitates the suction of dirt and dust. * C In various modalities, it may comprise a unitary, telescopic or pipe connection section, such as an aluminum pipe. Near the base assembly, a hose 220, flexible for user manipulation, connects and also facilitates the suction of dirt and dust. 230 that has ends 217219 is mechanically and fluidly connected to the rod 218 as the hose 220 and allows a path or path of air flow between the nozzle assembly and the suction fan motor of the base assembly7 ~ "* ---- - "In any embodiment of floor care apparatus, the vacuum cleaners have a circuit for controlling the agitator motor 310 to move the agitator motor 340 to two or more speeds, in turn, the agitator motor moves the agitator of the vacuum cleaner to two or more speeds, in this way, and in front of the user of a p; mode-of-operation eference), thus indicating a speed preference (when manipulating a switch, SW, the agitator cleans at a first rotation speed for certain types of floors and at a second speed for other types of floors. that the agitator motor 340 (alternatively: motor 40, FIG. 11) is not the vacuum motor to create a suction air flow, for example fan motor of uction 3 (Figure 1), this change in speeds of The agitator will not affect the suction power of the vacuum cleaner, however, it will be able to reduce the speed of the full speed agitator at a lower speed, thus minimizing or avoiding: damage to certain floor types.

In a simplified illustration, the control circuit 310 includes a bridge rectifier 312, a synchronizer 314 and a transistor, preferably a MOSFET or other switch 316. A diode 318 exists in parallel with the "motor-agitator. synchronizer opens or closes the gate of the MOSFET, in this way by pressing or not the agitator motor linked between a power source and the MOSFET source The bridge rectifier transforms the line voltage, for example 120 Vac, 60 Hz, into a voltage CD which serves as the power source for the agitator motor During use and in response to the position of the switch SW, the control circuit 310 produces a MAG output signal through the terminals 320, 322 which already have a signal cycle fixed service, having a substantially rectangular voltage waveform 410 (Figure 4B) or a substantially concentric voltage signal waveform 420 (Figure 4A) In one aspect, the service cycle fixed is approximately ft.25 [in on / total time on and off] corresponding to a rectangular shape with a substantially constant voltage value B2, which is on for a first quarter (zero time to time 0.25T) of four quarters of the waveform period T. Subsequently, the waveform is repeated for periods Additional 2T, 3T, 4T, 5T, etc. In this way, if the line voltage is Vac, the agitator motor receives an average voltage value (at an equivalent voltage value CD downstream of the bridge rectifier) that corresponds to approximately. _, _ 0_.25 x 120 or approximately io V. When the signal is a constant voltage value signal, the agitator motor control circuit produces an agitator motor voltage corresponding to VI which, in turn, corresponds to approximately '00% of the line voltage (again this corresponds to an equivalent DC voltage downstream of the bridge rectifier.) In another aspect, the fixed service cycle is approximately 0.5 corresponding to a rectangular waveform with a substantially constant voltage value that is on for the first two four-fourths of the waveform period, then the waveform is repeated for additional periods, of course, 0.25 or 0.5 waveforms for fixed service cycle voltage may have variations in the which of the rooms, or other divisions of the waveform period are turned on and off.Further in other aspects, the service-fixed cycle may be greater than 0.5 or less to 0.25 or between these two values. Finally, the agitator is either • operated at a voltage corresponding to approximately 100% of the line voltage or approximately 25 to 50% to improve cleaning in different floor styles. For 100%, or full speed, the rotator rotates at approximately 3000 to approximately 000"rpm ~ ~ In-shape-most.prefer._ble, rotates at approximately 3500 rpm.Other times, it rotates at approximately 800 to approximately 2000 rpm, more preferably, rotates at about 1750 rpm, or half speed, however, persons skilled in the art will understand that the agitator rpm, the current duty cycle of the pulsed or repeated rectangular voltage waveform output signal and the constant voltage level signal may vary according to the manufacturer's preferences With reference to Figure 5, a most preferred motor stirrer control circuit 510 includes various resistor, capacitor, diode and transistors for trimming a micro-synchronizer. traditional chip or microprocessor 555. As a matter of numerical reference convention, however similar elements in Figures 3 and have digits of 1 and 10 of their number corresponding references to each other. For example, the bridge rectifier in Figure 3 has a reference number of 312 while in Figure 5 it has a reference number 512. The specific parts of the control circuit 510 follows the entries in the following Table. PART DESC. R6 resistor 1 watt 16 KO R5, R15 ~~~ resistor -0 25 -watt _3..3 .___ * < O R4, R14 resistor 0.25 watt 1.0 KO R3 resistor 0.25 watt 11.5 < O R2 3.25 watt resistor 1.5KO R16, R7 cesistor 0.25 watt 2.0 KO Rl resistor 0.25 watt 10 KO C2 Capacitor lOOμf 35V Cl, C3: apacitor 0.22 μf 25V C4 Capacitor 220 μf 250V D2 'ener IN4741 DI Jiodo IN40004 Ql, Q4 Transistor 2N3904 D4 Zener 180V 1N5279 Q2 '' Transistor IRF 640 Ul '_M555 Synchronizer Cl D7 < .Drug IN5404 X3 * "Bridge Rectifier In Figure 6, a control switch 624S preferred to be placed in a preferred vacuum handle 22 Figure 1), for example, includes a 626 a-up position, a bare floor / BERBER-528 position and a 630"carpet position. In these", "" he positions "" user -indicates-his-mode-of-operation preference, thus indicating agitator speed because the agitator motor control circuit will then displace the agitator motor to keep the agitator off, the agitator at approximately 3500 rpm or approximately 1700 rpm, respectively The switch has a finger or thumb slide 632 that moves in the direction of arrows A or B by user manipulation In Figure 7, a basic circuit diagram illustrates the suction fan motor 733, in parallel with a printed circuit board 742 and the agitator motor 7i0, as between electric terminals 731, 735. The printed circuit board preferably contains the circuit for motor control a gitator. * Appreciating that many modern vacuum cleaners house multiple agitators in a single nozzle assembly, the present invention also contemplates operating multiple agitacores at various speeds. In Figure 8A, first and second agitators 838, 839 obtain? your own dedicated agitator motor AG2 or AGÍ, respectively. In Figure 8B, agitators 838, 839 have left (L) and right (R) bifurcated halves displaced with a single agitator motor 840. To achieve separate speed control for each agitator, a gear mechanism ~ 842-- can there is _ in__ the control line between the agitator motor and one of the agitators. Of course, the motor and gears in Figure 8B can replace! the multiple motor mode of Figure 8A or vice versa. Some modes of speed control include turning or operating the agitators with the same speed, in the same directions; same speed, different directions; different speeds, same direction or different speeds, different directions. In a simple circuit, a user can control the multiple motor modes 940 AGI, 940 AG2 of multi-speed agitators by creating an agitator motor concrol circuit 910 having parallel circuits for the agitator motor control circuit 310 of 3. Figure 3. '• Still another embodiment, the circuit for control of the agitator motor receives as components of physical equipment or software with respect to a microprocessor 1028 and an output of which controls the agitator motor 1040 as previously described. A user-operated switch 1024, to indicate mc preference, do-of-operation, thereby indicating agitator speed, incorporates a resistor network having a plurality of resistors of equal value r symmetrically connected to -un_. series__of buttons or pushbuttons selected by the user with numbers 1- 5. In this way, by selecting a single button (which in one aspect can be a micro switch or other momentary switch on or permanently turned on), a v-ilor of particular voltage Vm appears on the power terminals of a digital analog converter (A / D) 1026, in turn providing power to the microprocessor. Since the inventory A / D components have specified power * voltage ranges, the vacuum cleaner manufacturers can select resistor values to make Vm appear within a suitable voltage range and the button selected by the particular user can be electrically impeded. Mathematically Ym = Rtotai x Ip where Rtotai is an equivalent resistance value for switch 1024 appearing at terminals 1030, 1032 and Im is a fixed current source - connected between negative terminal Vm and common -24V. In a preferred embodiment: (1) Vm is 0.416v for "an acceptable A / D supply voltage range of 0 - 0.833 v and this corresponds to the user depression of button number 1; operationally, the suction fan motor is off (persons with dexterity will appreciate that" the control-of, suction fan motor is a well-known practice); (2) Vm is 1.25v for an acceptable A / D supply voltage range of (. '.. 833 - 1.66 and this corresponds to the user depression of button number 2; operationally, the suction fan motor is low; (3) Vm is 2.08v for an acceptable A / L supply voltage range of 1.66 2.499 and this corresponds to depression of button number 3. Operationally, the suction fan motor is medium; (4) Vm is 2.92 for an acceptable A / D supply voltage range of 2.499 - 3.33 and this corresponds to pressing the number 4 button, operationally, the suction fan motor is high; (5) Vm is 3.75v for a supply voltage range A / C acceptable of 3.33 -4.16vy and this corresponds to depression of the number 5 button, operationally, the suction fan motor is high and the agitator is off, and (6) Vm is 4.58v for a range "5 of supply voltage Acceptable A / D of 4.16 - 4.999 and this corresponds to that there was no oppression of no button; Operationally, there are no engines working. The foregoing has been selected and described to provide the best illustration of the principles of the invention and its practical application in order to enable a person with ordinary skill in the art to use the invention in various modalities and with various methods. modifications as are suitable for - 1 particular use contemplated. All these modifications and variations are within the scope of the invention as determined by the appended claims when interpreted according to the extent and to which they are entitled in a fair, legal and equitable manner.

Claims (5)

1. CLAIMS 1. A floor care apparatus, characterized by comprising: a nozzle assembly; an agitator in the nozzle assembly; a motor coupled to the agitator, "to move the agitator -in-two-or-more-speeds, a switch with at least two positions for a user to indicate a mode-of-operation preference, and a circuit for motor control agitator in response to the switch and coupled to supply at least two signals "to the motor; one of the two signals has a fixed service cycle less than 1.0, the other of the two signals is substantially constant.
2. 2. Fl appliance for floor care in accordance with > Claim 1, characterized in that the fixed service cycle is one of approximately 0.25 and approximately: 0.5.
3. 3. The floor care apparatus according to claim 1, characterized in that one of the two signals includes a waveform having a period with a substantially constant voltage value, which is lit by only one or two of four quarters dsl period, the waveform is repeated for additional periods.
4. 4. The floor care apparatus according to claim 1, characterized in that It also includes a motor suction fan motor coupled to a 3 agitator.
5. 5. V? floor care apparatus according to claim 1, characterized in that the operation of the "switch" changes the resistor connections, such that a voltage supply to an analog-to-digital converter drops. Within a specified power range for the analog-to-digital converter 6. The floor care apparatus according to claim 5, characterized in that a total resistance value of the multiplicity resistor connections by a source value. Fixed current determines the voltage supply 7. A floor care apparatus, characterized in that it comprises: a nozzle assembly, a first and second agitators in the nozzle assembly, a circuit for agitator motor control to displace the first agitator at a first and second speeds and the second agitator at first and second speeds, the first and second speeds of each of the first and second agitator js is one of the same speed and a different speed. 8. The floor care apparatus according to claim 7, characterized in that it also includes a first and a second motor to move the prinier and second agitators. 9. The floor care apparatus according to claim 7, characterized in that it also includes "" "" a "motor to displace .__. The .first ___ and _ second agitators 10. The apparatus for care of floors in compliance furthermore, it includes a gear mechanism between one of the motor and the first agitator and the motor and the second agitator, which is not located between the other of the motor and the first agitator and the motor and the second agitator. 11. The floor care apparatus according to claim 7, characterized in that it further includes a switch with at least two positions for a user to indicate a mode-of-operation preference, such as by indicating a preference of the first and second speeds, the circuit for control of the agitator motor responds to the switch 12. The floor care apparatus according to claim 11, characterized in that the output of the circuit or for agitator motor control, one of a signal has a fixed duty cycle less than 1.0 and a signal is substantially constant. - 13. - The floor care appliance according to claim 12, characterized in that the fixed service cycle is one of approximately (.25 and approximately 0.5. "~ ~ according to claim 12, characterized in that one of the signals having the fixed-service cycle includes a waveform, which has a period, with a substantially constant vol- ume value that is on for one or two four-fourths of the period, the waveform is repeated for additional periods. 15. The floor care apparatus according to claim 7, characterized in that it also includes a fan motor with suction separated from a motor coupled to one of the first and second agitators. 16. The floor care apparatus according to claim 7, characterized in that it also includes a switch with at least two positions so that "a user indicates a mode-of-operation preference, thus indicating a preference of the first and second. speeds, the agitator motor control circuit responds to the commutator where the operation of the commutator changes resistor connections, so that a voltage fed to an analog converter digit:;, falls within a specified power range for the analog to digital converter. 17. A vacuum cleaner, characterized in that it "comprises: an efe motor" suction fan "" for "providing a suction air flow during use; a nozzle assembly, in fluid communication with the suction fan motor, a path or air flow path that exists from the nozzle assembly to the suction fan motor; at least one agitator in the nozzle assembly; an agitator motor coupled to at least one agitator to move the agitator in two or more speeds; a switch with at least two positions for a USER to indicate a mode-of-operation preference, in this way indicating a preference of two or more speeds, and a circuit for motor control and response to the switch and coupled to supply at least two signals to the agitator motor according to the speed preference 18. The vacuum according to claim Y, characterized in that the agitator motor does not exist in the air flow lute. according to claim 17, characterized in that one of the two signals has a rectangular voltage waveform substantially repetitive with a fixed service cycle of approximately 0.25 or 0.5. 20. The vacuum cleaner according to claim 17, characterized in that the other of the two signals is a voltage level that is substantially constant. 21. The vacuum cleaner according to claim 1, characterized in that it also includes a second motor to displace a second agitator. The vacuum cleaner according to claim 1 /, characterized in that one of the two signals includes a waveform having a period with a substantially constant voltage value that is turned on by only one or two four fourths of the period, the The wave pattern is repeated for additional periods. 23. The vacuum cleaner according to claim 17, characterized in that the operation of the switch changes resistor connections in a circuit, such that a voltage fed to an analog-to-digital converter falls within a specified supply range for the converter. analog to digital. 24. The vacuum cleaner according to claim 2: 3, characterized in that a value of Total resistance of the resistor connections or multiplied by a current value of a fixed current source, determines a voltage value of the voltage supply. 25. A vacuum cleaner, characterized in that it comprises: a suction fan motor to provide a suction air flow during use; a nozzle assembly in fluid communication with the suction fan motor, for sucking dirt and debris from a surface to be cleaned, a path or air flow path that exists from the nozzle assembly to the suction fan motor; at least one agitator in the nozzle assembly; an agitator motor coupled to at least one agitator, to move the agitator with two or more velocities; the agitator motor does not exist in the air flow path; a switch with at least two positions for which a user indicates a mode-of-operation preference, thereby indicating a speed preference of the two or more speeds; and a circuit for controlling the agitator motor in response to the switch and coupled to supply at least two signals to the agitator motor according to the velocity preference, wherein one of the two signals has a 'form'. rectangular voltage wave substantially repetitive with a fixed service cycle and the other of the Two signals have a substantially constant voltage level.