FIELD OF THE INVENTION

[1 ] The present invention is in the field of mechanical and electrical engineering, particularly in technology related to the treatment of fabrics and removal of stains.

STATE OF THE ART

[2] Systems and devices for treating and removing stains from fabrics are known in the art. As an example, we may cite U.S. patent applications US 2003/084535 A1 and US 2004/250844 A1 , and European patent application EP 1 195460 A2.

[3] US 2003/084535 A1 discloses an ultrasonic cleaning device comprising an ultrasonic oscillator (sonotrode) and a power source adapted to supply current to the ultrasonic oscillator. Such a cleaning device further includes a base comprising the oscillator, and the power source, and a stain removal device connected to that base.

[4] Similarly, U.S. patent application 2004/250844 A1 discloses an ultrasonic cleaner which includes a body section, a vibration generator mounted in the body section and a vibration transmission portion formed at its rear end to impart vibration to an object to be cleaned, in addition to a feeding section to feed the cleaning medium to the object to be cleaned. The vibration transmission portion is pressed against an object to be cleaned to thereby transmit the vibration to the object to be cleaned. Thus, the vibration causes the adhering dirt to be diluted in the cleaning medium from the object to be cleaned, thus removing the dirt from the object.

[5] European application EP 1 195460 A2 describes an ultrasonic cleaning apparatus which comprises a power amplifier which supplies the signal as power to the ultrasonic oscillator, a phase comparator for obtaining a difference between a phase of a current flowing through the oscillator and a phase of a voltage applied to the ultrasonic oscillator, and to generate a voltage according to the phase difference, and a voltage control oscillation device to generate a frequency of the signal according to the voltage generated by the phase comparator and to control the frequency so that the phase difference is maintained within 30°, wherein the power supplied to the oscillator ultrasound detector is set between 1 W to 10W, and the difference between a resonance frequency of the ultrasonic oscillator and its anti-resonance frequency is set to 1 KHz or more.

[6] As can be seen in the description of the applications at stake, the elements comprising such oscillator devices are large, generally having a base with control elements and frequency generators, and a device connected thereto which actually cleans the fabrics. Furthermore, such elements generate non-anatomical, difficult-to-use cleaning devices.

[7] Finally, the control of these devices is usually accomplished by using a "classical" PLL approach, as can be seen in particular in the European document, and such a control has a major disadvantage in that there are two states that possess the same 0° phase condition between transducer voltage and current, i.e. purely resistive, wherein the first state is the desired for use in the removal of stains (resonance) and the second stage is unwanted for the removal of stains (anti-resonance).

[8] Also, it is important to note that the frequency difference between resonance and anti-resonance is extremely small, usually only 2 KHz. Thus, the ideal control solution should position itself only at the resonance of the transducer, and "block" or "lock" for this state in a closed loop control. The performance of this control is not trivial due to

disturbances introduced by the "mechanical load" of the cleaning device tip, such as differences in contact pressure on the treated cleaning surface, this action in practice shifts to lower frequencies in the resonance and consequently on the anti-resonance of the transducer. Such devices of the prior art do not at any time carry out a control so as to keep the system in resonance and thus can easily end up in anti-resonance during charge changes. [9] There are also in the prior art applications relating solely to the control of high-vibrating elements, among which may be mentioned U.S. Patents 4,703,313 A and 4,939,402 A, and U.S. Patent Application

2002/049555 A1 .

[10] US 2002/049555 A1 describes a control for an ultrasonic surgical system, configured to perform two distinct functions, a first one to make incisions in certain types of human textures and a second one to cauterize textures. Such control, although similar to that of fabric cleaning devices, has different functions, such as temperature control (extremely high temperatures) to effect coagulation, vaporization control and fumes. Additionally, the use of such instruments often results in relatively wide zones of thermal damage to the textures.

[1 1 ] US patents 4703213 A and 4939402 A describe piezoelectric vibrating drive circuits, again comprising PLL (Phase Lock Loop) controlled oscillators to generate and transform the transmission of drive energy to the transducer, still using parts of the energy of transformers to carry out such controls. Obviously, such controls still remain with the same problems previously mentioned.

[12] Thus, none of the foregoing documents solves the problems inherent in the prior art, that is, none of the documents can provide a compact control unit, so as to enable the creation of an ergonomic device, in addition to providing a control method that enables the effective

"blocking" of the operating frequency of the cleaning device at the resonant frequency, even with disturbances introduced by the "mechanical loading" of the cleaning device tip.

BRIEF DESCRIPTION OF THE INVENTION

[13] The present invention relates to an ultrasonic stain removing device in fabrics, comprising: a portable stain removal unit comprising an ultrasonic transducer, a power component electrically connected to the portable stain removal unit and to an energy inlet configured in order to provide energy to the operation of the ultrasonic transducer, a control component electrically connected to the portable stain removal unit, which provides an electrical waveform with a variable frequency to the ultrasonic transducer, the control member being configured to control the operation of the ultrasonic transducer by controlling the frequency delivered to the ultrasonic transducer, wherein the control component comprises a phase- locked loop member configured to block the frequency delivered to the ultrasonic transducer at a frequency of resonance, wherein the phase lock loop element comprises a frequency sweep element and a phase comparator element configured to determine the phase difference between the voltage applied to the ultrasonic transducer and the current flowing through the ultrasonic transducer in that the control component controls the frequency delivered to the ultrasonic transducer by means of phase difference determined between the voltage applied to the ultrasonic transducer and the current flowing through the ultrasonic transducer.

[14] In an alternative configuration the control member modifies the frequency according to the phase difference between the phase of the voltage applied to the ultrasonic transducer and the phase of the current flowing through the ultrasonic transducer if the phase of the voltage applied to the ultrasonic transducer and phase of the current flowing through the ultrasonic transducer are not the same.

[15] In addition, the control member may comprise a cut-and-reset element configured to reset the frequency sweep element to a minimum frequency if the frequency modification equals or exceeds a maximum frequency.

[16] Preferably, the minimum frequency is 20KHz and the maximum frequency is 60KHz.

[17] In this regard, in a preferred configuration, the frequency sweep element is formed by an integrator and a voltage-controlled oscillator.

[18] In one configuration, the power unit, comprising a housing comprising a front body, a back body and a plug for power connection, wherein the power unit comprises the power component, the control member, and a connector for an electrical cable that electrically connects the power unit to the portable stain removal unit.

[19] In such a unit, the power component comprises a power plate into which electronic components are secured, and the control member comprises a control plate in which electronic components are secured, the power component and the control member are disposed side by side, or even where the power plate and the control plate are arranged face to face, and the electronic components are disposed therebetween.

[20] Preferably wherein the electronic components of the power component protrude out of the power plate are positioned in the blanks of the control plate, and electronic components of the control component protrude out of the control plate are positioned in the blanks of the power plate.

[21 ] In still further configurations, the ultrasonic fabric stain remover may comprise a base configured to receive the portable stain removal unit, wherein the base may also comprise the power component and the control member so as to that the portable stain removal unit and the base are electrically connected. Such a base may comprise a reservoir of water and / or stain removal additives, wherein the portable stain removal unit and the base are fluidly connected, and preferably the portable stain removal unit has a pen shape.

[22] Preferably, the frequency modification is performed by means of an increase or a decrease of the input voltage in the frequency sweep element.

[23] The present invention further relates to a method of controlling a stain removal ultrasonic device comprising a portable stain removal unit comprising an ultrasonic transducer, the method comprising the steps of: providing an electrical waveform with a minimum frequency for the ultrasonic transducer, determining the phase difference between the voltage applied to the ultrasonic transducer and the current flowing through the ultrasonic transducer, and modifying the frequency supplied to the ultrasonic transducer according to the phase difference to block the frequency supplied to the ultrasonic transducer at resonant frequency.

[24] In an alternative embodiment, the method of controlling the step of modifying the frequency delivered to the ultrasonic transducer by means of phase difference determined between the voltage applied to the ultrasonic transducer and the current flowing through the ultrasonic transducer is performed so that the phase of the voltage applied to the ultrasonic transducer and the phase of the current flowing through the ultrasonic transducer are not the same, modifying the frequency during a step of sweeping a frequency band according to the phase difference between the phase of the voltage applied to the transducer and the phase of the current flowing through the ultrasonic transducer.

[25] Preferably the step of sweeping the frequency range exceeds a maximum frequency, restarting the device with a minimum frequency, wherein the minimum frequency is 20KHz and the maximum frequency is 60KHz.

[26] Obviously, such a method is preferably performed to control an ultrasonic stain remover device as previously defined.

BRIEF DESCRIPTION OF THE DRAWINGS

[27] Figure 1 is a perspective representation of an ultrasonic device for removing stains in fabrics according to a first embodiment of the present invention;

[28] Figure 2 is a perspective representation of an ultrasonic device for removing stains in fabrics according to a second embodiment of the present invention;

[29] Figure 3 is an exploded view of an ultrasonic device for removing stains in fabrics according to the first embodiment of the present invention;

[30] Figure 4 is a perspective representation of an ultrasonic device for removing stains in fabrics according to a third embodiment of the present invention in a storage position; [31 ] Figure 5 is a perspective representation of an ultrasonic device for removing stains in fabrics according to a third embodiment of the present invention in a position of use;

[32] Figure 6 is a bottom view of an ultrasonic device for removing stains in fabrics according to a third embodiment of the present invention in a storage position;

[33] Figure 7 is a right-side view of an ultrasonic device for removing stains in fabrics according to a third embodiment of the present invention, in a storage position, the left side view being a mirror view thereof;

[34] Figure 8 is a top view of an ultrasonic device for removing stains in fabrics according to a third embodiment of the present invention in a storage position;

[35] Figure 9 is a block representation of a control of an ultrasonic device for removing stains in fabrics according to a preferred embodiment of the present invention;

[36] Figure 10 is a graph depicting the output function of part of the frequency control block according to an embodiment of the present invention, namely the integrator, the voltage-controlled oscillator, and the cut-and-restart component;

[37] Figure 1 1 is a graph depicting the output function of the phase comparator according to one embodiment of the present invention;

[38] Figure 12 is a status diagram representing the status of the phase comparator according to one embodiment of the present invention; and

[39] Figure 13 is a signal diagram representing multiple control signals according to an embodiment of the present invention, as well as their relationship.

DETAILED DESCRIPTION OF THE INVENTION

[40] Figures 1 to 13 illustrate representations of ultrasonic devices for removing stains in fabrics in accordance with the embodiments of the present invention, as well as their graphics, methods and status of usage. Thus, the present invention consists of a solution for the removal of stains in fabrics using an ultrasonic cleaning transducer. Further, the scope of the invention includes a control solution of the concept of transducer.

[41 ] Such ultrasonic device for removing stains 1 according to Figure 1 comprises a tension adapter 3, a stain removal unit 2, a container 4, and a lid 5, wherein the tension adapter 3 and the stain removal unit 2 comprise an electrical connection. Figure 2 illustrates the same

configuration without the electrical connection and the voltage adapter 3, wherein the ultrasonic stain remover 1 ' comprises a stain removal unit 2', a container 4 ', and a lid 5'.

[42] Further, Figure 3 shows an exploded view of an exemplary constructive embodiment of the ultrasonic stain remover 1 , comprising a lens 1 1 , a ring 12, a transducer 13, a LED board 14, a switch board, of the stain removing unit 15, a female cable connector 16, a body of the stain removal unit comprising a lower portion 17 and an upper portion 18, a male cable connector 19, a cable connector 20, a right-hand spring 22, a power component 23, a frequency control component 24, and a power unit comprising a front body 25, a rear body 26 of the power unit, and a plug 27 of the power unit.

[43] In this regard, in the exemplary configuration, the lens 1 1 is positioned to distribute the light from the LED plate 14, in order to check the operating status of the device, the ring 12 firmly positions the transducer 13 in a correct position, and the left hand spring 21 and right hand spring 22 are positioned so as to enable receipt and removal of the plug 27 from the power unit, depending on the socket being used (which may be distinct such as a Brazilian, European or Chinese sockets).

[44] In this regard, in the configuration in which the device comprises the power unit, the power unit comprising a housing comprising a front body 25, a rear body 26 and a power connection plug 27, wherein the power unit comprises the power component 23, the control member 24, and a connector for an electric cable that electrically connects the power unit to the portable stain removal unit 2, 2'. In this case, the power component 23 comprises a power plate in which electronic components are attached, and the control component 24 comprises a control plate in which electronic components are attached.

[45] In this case, the power plate and the control plate may be arranged face to face, and the electronic components are disposed therebetween, or the power component 23 and the control member 24 may be arranged side by side, to minimize the size of the elements and to allow the power unit to be positioned internally. In this regard, in a specific configuration, the electronic components of the power member 23 project out of the power plate and are positioned in the blanks of the control plate, and electronic components of the control member 24 project outwardly from the control plate being positioned in the void spaces of the power plate so that the space occupied by such components is minimal.

[46] During the operation of the cleaning method of the present invention, it is noted that a second fabric or a carrier may be positioned under the fabric containing the stain so that when the stain removal unit 2, 2' is positioned in contact with the stain with the stain removal unit 2, 2' preferably in the upright position, and by pressing the button 200 disposed in the rear portion of the unit 2, 2' and thereby activating the ultrasonic transducer 100 on the stain, and further with the addition of a fluid, usually water, in order to moisten the fabric to be treated in the region of the stain to be cleaned, since the moist stain guarantees a better removal efficiency. In addition, movements, preferably circular, should be performed by passing the lens 1 1 of the stain removing unit 2, 2' delicately over the full extent of the stain so that as the dirt contained in the stain is detached from the fabric, preferably excess dirt and water remaining on the fabric must be removed with an absorbent paper or clean cloth.

[47] It should also be noted that the vibration emitted by the transducer at a high frequency generates an ultrasonic cavitation in the fluid in contact with the stain, which creates impact waves over the stain, which removes the stain for the underlying fabric.

[48] Specifically in relation to Figures 4 to 8, they illustrate a second alternative embodiment, wherein the ultrasonic stain remover device 1 " comprises a stain removal unit 2", provided with the button 200, of a fluid and electrical communication means 201 and a pump, a base 6 and a tension adapter 3", wherein the stain removal unit 2" is coupled to the base 6. It should be noted that in this second alternative embodiment the power control plate is disposed within the base 6. In addition, it is worth mentioning that the base 6 further comprises a reservoir, which allows the conditioning of a fluid, usually water, but any other liquid such as stain removers, liquid soap, softener, among others, provided it makes it possible to moisten the stain region. Said reservoir allows the user, through the pump arranged in the stain removal unit 2" and fluid communication 201 with the stain removal unit 2", to direct/dispense the fluid in the stain region so as to ensure a better efficiency in the stain removal. In addition, Figure 5 depicts the ultrasonic device for removing stains 1 " with the stain remover unit 2" decoupled from the base 6, thereby allowing the display of the fluid and electrical communication medium 201 between the base 6 and the stain remover unit 2". In this configuration, a stain removal unit 2' may comprise an internal energy element, such as a battery.

[49] Figure 6, on the other hand, illustrates a bottom view of the ultrasonic device for removing stains 1 ", which makes it possible to visualize the electromechanical communication medium 301 between the tension adapter 3" and the base 6. In the present embodiment the electromechanical communication 301 is provided by the attachment of an electromechanical plug 302 of the voltage adapter 3" to a connecting portion 600 disposed in the base 6. In order to ensure that the plug 302 remains attached to the connecting portion 600, the base 6 has a recess portion 601 which allows the plug to be accommodated and / or protected therein and the base 6 further comprising a labyrinth 602 which allows to the electromechanical communication means 301 of the voltage adapter 3" to be accommodated and/or protected, ensuring adequate

electromechanical communication. Additionally, the base 6 has in its lower portion a socket 604 which enables the stain removal device 1 " to be attached to any desirable surface.

[50] Figures 7 and 8 respectively show the stain removal device 1 " in two further views, side and top views, views which enable to view the stain remover unit 2", the tension adapter 3" and the base 6 of the device 1 " in a different angle, which allows to distinguish said device 1 " from others available in the state of the art.

[51 ] In this regard, in the embodiments of the present invention, the controller may comprise a feeder unit, configured to electrically feed the ultrasonic device for removing stains and the controller for ultrasonic device for stain removal in fabrics.

[52] Thus, in the exemplary configurations according to Figures 1 to 8, the simplified arrangement of the control board and the elements enable the portable stain removal unit to have a smaller dimension than the units described in the prior art, being thus more ergonomic, thereby facilitating their handling when in use, such as in settings where the power and control components are not arranged in the portable stain removal unit.

[53] In this sense, with regard to the operation of the cleaning method of the present invention and using the second embodiment of the stain removing unit 2", it is noted that, also a second fabric can be positioned under the fabric containing the stain. After that step, preferably the voltage adapter 3" is connected to the power source, then the fluid reservoir which may contain the fluid, then the unit 2" is preferably positioned in the upright position.

[54] After the above described steps, the button 200 is preferably tightened/actuated, thereby activating the pump and causing the fluid to be applied onto the stain so as to moisten the fabric to be treated in the region of the stain to be cleaned, since the moist stain guarantees a better removal efficiency. After the stain has been moistened, the button 200 should again be pressed in order to activate the ultrasonic transducer 100 since the vibration emitted by the transducer at a high frequency

generates an ultrasonic cavitation in the fluid in contact with the stain, which creates impact waves on the stain, which removes the stain to the underlying fabric. Obviously, two buttons can be used in an alternate embodiment, one of which relates to the use of the fluid and another to the activation of the ultrasonic transducer. Other normal methods of control of such elements may also be used.

[55] In addition, preferably circular movements should be performed by passing the transducer 13 of the stain removal unit 2" delicately over the entire extent of the stain, so that as the dirt contained in the stain is detached from the fabric, preferably removing the excess dirt and water that is left on the fabric with an absorbent paper or a clean cloth.

[56] In this sense, it is clear that different users can use the ultrasonic stain removal device 1 , 1 ', 1 " either with different applied mechanical forces, with different velocities of the circular movements, or even when the excess dirt and water is removed.

[57] Thus, it is a primary object of the present invention to provide a controller for an ultrasonic device for removing stains in fabrics which is independent of the applied force, of the speed of movement or of the time of removal of excess dirt and/or water.

[58] Figure 9, on the other hand, shows a block diagram of a control of an ultrasonic device 1 " for removing stains in fabrics, wherein the control comprises an integrator 91 , a voltage controlled oscillator 92, a cut- and-restart component 93, a duty cycle component 94 or work cycle, a dead time control component 95 or dead time circuit, a drive member 96, a voltage change detection circuit 97, a detection circuit of change of current 98, a phase controller 99, and an ultrasonic transducer 100.

[59] Regarding its operation, and as can be seen in Figure 10, assuming that initially the output of the integrator 91 is a minimum input voltage, it should be noted that this is a normal condition in the

energization, the output of the integrator 91 directs the controlled oscillator by voltage 92 to the minimum frequency Fmin of approximately 20 KHz.

[60] Consequently, the system is commonly in the First State 1 1 1 , i.e. below the resonance, the impedance is capacitive, the phase comparator 99 has positive pulses at the output (according to Figures 9 and 13) and the output voltage of the integrator 91 is gradually increased. Additionally, this increasing voltage at the input of the voltage controlled oscillator 92 increases the frequency in a control circuit until it reaches a balance in the resonance frequency or the Second Status fr. The resonant frequency is determined primarily by mechanical characteristics of the transducer, but other elements which will be described later, may influence such value, in this case, preferably 44 KHz.

[61 ] As can be seen in Figure 1 1 , and in relation to the ultrasonic cleaning transducer 100, we can define five different working status, First Status 1 1 1 , where the frequency is less than the resonance (hence the impedance is capacitive), Second Status fr, where the frequency is in the resonance range (hence the impedance is low and purely resistive), Third Status 1 12, where the frequency is above the resonance but lower than the anti-resonance (so the impedance is inductive), Fourth Status far, where the frequency is exactly at the anti-resonance (thus the impedance is high and also purely resistive) and Fifth Status 1 13, where the frequency is greater than the anti-resonance (so the impedance is capacitive), the system is then restarted and reaches a system reset status 1 10, with the minimum frequency.

[62] It is therefore important to emphasize that the primary function of the control circuit of the device 1 " is to direct the ultrasonic transducer 100 to be constant and regularly in the Second Status fr, i.e. at the resonant frequency. In this respect, it should be noted that a frequency difference of only 2 kHz separates the resonance and anti-resonance status.

[63] In relation to the solutions described in the state of the art, and when considered a "classical" PLL (closed phase loop) approach, a major disadvantage remains clear, in the solutions described in the prior art there are two Status in phase, the Second Status fr and the Fourth Status far, being that they have the same condition of phase of 0° between tension and current of the transducer, that is purely resistive, but only the Second Status fr is the one that is efficient for the removal of stains, since it uses low impedance. Thus, when in the Fourth Status far, the removal will not be effective. Thus, a suitable solution must find only the resonance of the transducer and "block" for this status in a closed-loop control.

[64] It is important to note that the performance of only this Second Status fr is not trivial, mainly because of the perturbations introduced by the "mechanical load" of the tip, that is, the contact pressure of the tip of the device on the contact/stain surface to be cleaned. This action of contact pressure of the tip of the device in practice shifts to lower frequencies both the resonance and consequently the anti-resonance of the transducer. At resonance, the Second and Fourth Status are in phase, the output of the phase comparator 99 emits the signal on hold or "hold" and the system is "locked".

[65] It is then necessary for the system to address disturbances, which move the frequency slightly. In this case the closed loop regulates to a stable resonance point because if the system moves to the Third Status 1 12 (inductive), it generates negative pulses and the integrator voltage decreases if the system moves to the First Status 1 1 1 (capacitive), it generates positive pulses and the output of the integrator increases again, in both cases without relevant conditional changes in the transducers, the control thus proposed regulates the stable frequency for the resonance in the Second Status fr.

[66] At a different time, with a more relevant change in the load condition of the transducer, as previously mentioned, the resonant frequency alternates to a higher value, but also the anti-resonance, in this case for example 46 Khz. Considering that there is no great difference between the two frequencies, we can assume that in some critical conditions/transitions can suddenly move from the Second Status fr to the Fourth Status far.

[67] In this case the regulating loop diverges to the Fifth Status 1 13, and this happens because the impedance becomes again capacitive, the regulation loop generates positive pulses, the output voltage of the integrator increases and consequently the frequency of the voltage- controlled oscillator theoretically increases up to the limit of the upper range of the voltage-controlled oscillator and gets "stuck" to a non-working condition at a rather high frequency.

[68] Instead, the proposed solution introduces into the circuit a cut- and-reset component 93, which monitors the integrator 91 , the output voltage, in the event that it exceeds a defined limit corresponding to Fmax, about 60 kHz for the present invention, the reset of the integrator circuit 91 resets the output and restarts an "increase frequency" cycle of Fmin, and again there is a gradual increase of the frequency until the frequency is again locked at the resonance frequency in the Second Status fr.

[69] Thus, the integrator and the voltage-controlled oscillator of the present invention form a frequency sweep generator, preferably sweeping a range between 20kHz and 60kHz to determine the correct resonance frequency and, if necessary, restart the system by means of the cut and restart 93 component.

[70] In addition, it should be noted that all of the above described functionalities can be properly implemented to a microcontroller and an appropriate "SW" real-time control, which emulates the functionality of the "HW" blocks described above. In addition, this control system in a very small and compact layout, allows the creation of ergonomic product concepts.

[71 ] When considering all the features of the above-described stain removal device 1 , 1 ', 1 ", the advantages over the devices described by the state of the art are clear and evident, among which may be highlighted: i) self-adjusting ultrasonic directed frequency/resonance to which it is not necessary to trim, compensate the wear/thermal variations of the ultrasonic tip, being adapted to different working conditions (i.e. tip pressure on textiles, ...), ii) no need to use a "bulky" transformer, which allows the miniaturization of the controller, iii) more reliable system, iv) portability, and v) ergonomic design.

[72] Thus, the method of controlling the ultrasonic fabric stain remover device of the present invention comprises the steps of providing an electrical waveform with a minimum frequency to the ultrasonic transducer 13, determining the phase difference between the voltage applied to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13, and modifying the frequency delivered to the ultrasonic transducer 13 according to the phase difference to block the frequency supplied to the ultrasonic transducer 13 at the resonant frequency. Furthermore, the step of modifying the frequency delivered to the ultrasonic transducer 13 by means of phase difference determined between the voltage applied to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13 can be performed such that if the phase of voltage applied to the ultrasonic transducer 13 and the phase of the current flowing through the ultrasonic transducer 13 are not equal, modifying the frequency during a step of sweeping a frequency range according to the phase difference between the phase of the voltage applied to the ultrasonic transducer 13 and the current phase flowing through the ultrasonic transducer 13. Preferably, the frequency of the voltage applied to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13 should be the same, and only its phase is different. Still, preferably, the initial input voltage provides a minimum frequency of 20KHz, and the maximum input voltage provides a maximum frequency of 60KHz. Obviously, such frequencies may be more specific such as, for example, a range between 35 KHz and 55 kHz, or even 40 KHz to 50 KHz.

[73] Therefore, in the present invention, the electronic blocks between the voltage controlled oscillator 92 to the ultrasonic transducer 100 are treatment and voltage amplification blocks, as duty cycle, dead time circuit, and transducer drive, such as, for example, duty cycle, which creates a perfect square wave with a logic signal of, for example, 0-5V, and the other blocks generate a square wave of higher voltage, such as 0- 40V. Obviously such values are exemplary and can be adapted depending on the elements used. Thereafter, the controller of the present invention includes a Phase Lock Loop (PLL) with voltage change detection circuit 97, current change detection circuit 98, and phase comparator 99, wherein the voltage change detection circuit 97 detects the phase of the voltage frequency and the current change detection circuit 98 detects the phase of the current frequency, and the phase comparator 99 compares the voltages to block the work frequency of the ultrasound transducer at resonance. The phase lock loop comprises the above-mentioned frequency sweep generator and the phase comparator blocks.

[74] Generally for this type of device, the resonance frequency means a frequency at which the oscillation is the largest and the impedance of the oscillator is low and the anti-resonance frequency is a frequency at which the impedance of the oscillator is high. Thus, the phase comparator determines a difference between a phase of the current flowing through the ultrasonic transducer and a phase of the voltage applied to the ultrasonic transducer, and generates a voltage (signal) to the sweep generator according to the phase difference. For example, the phase comparator generates the voltage equivalent to a time difference between a zero crossing point of the voltage and a zero crossing point of the current.

[75] As can be seen in Figures 12 and 13, the sweep generator in turn controls the (output) frequency to achieve the 0° phase condition between voltage and current (in phase). Specifically, it compares the input of the comparator 121 with the signal input 122 to determine several different status. When the input signal 122 is positive and the comparator input is zero, the comparator output is positive and the input of the voltage-controlled frequency oscillator is gradually increased. When the signal input 122 is positive and the comparator input is positive, the comparator output is bypassed and the voltage-controlled frequency oscillator input is maintained constant. When the signal input 122 is zero and the comparator input is positive, the comparator output is negative and the input of the voltage-controlled frequency oscillator is gradually decreased until it is cancelled.

[76] Thus, five different operating status can be determined. In status 1 , that is, below the resonance frequency, the impedance is capacitive, the comparator generates positive pulses for the frequency- increasing sweep generator. When the resonance is detected, status 2, the comparator stops sending signals to the sweep generator. In status 3, the impedance is inductive, the comparator generates negative pulses to the sweep generator that reduces the frequency. Thus, when, for whatever reason, the system jumps to the anti-resonance frequency (there is only 2 kHz between resonance and anti-resonance), at status 5, the comparator generates positive pulses to the sweep generator that increase the frequency up to the limit of the sweep generator in non-operating conditions.

[77] For this reason, the reset circuit monitors the frequency at the output of the integrator and resets the sweep generator to the lowest frequency (preferably 20 kHz) to restart the process when status 5 is reached, for example when 60 kHz is reached by the sweep generator.

[78] Thus, as can be seen in figure 13, the input is a square signal, as well as the comparator input, the comparator output being alternating pulses, and the voltage-controlled oscillator input is a step between the output pulses of the comparator. [79] Such solutions are made by means of an ultrasonic device for removing stains in fabrics, comprising: a portable stain removal unit 2, 2' comprising an ultrasonic transducer 13; a power component 23 electrically connected to the portable stain removal unit 2, 2' and to a power input, configured so as to provide power for the operation of the ultrasonic transducer 13; a control member 24 electrically connected to the portable stain removal unit 2, 2', which provides an electric waveform with a variable frequency to the ultrasonic transducer 13, the control member 24 being configured so as to control the operation of the ultrasonic transducer 13 by controlling the frequency delivered to the ultrasonic transducer 13; the ultrasonic device comprising the control member 24 comprises: a phase lock loop member configured to block the frequency supplied to the ultrasonic transducer 13 at a resonant frequency, wherein the phase lock loop member comprises a frequency sweep member; and a phase comparator element configured to determine the phase difference between the voltage applied to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13; wherein the control member 24 controls the frequency delivered to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13; wherein the control member 24 controls the voltage applied to the ultrasonic transducer 13 through the phase difference determined between the applied voltage to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13.

[80] Alternatively, the control member 24 may modify the frequency according to the phase difference between the phase of the voltage applied to the ultrasonic transducer 13 and the phase of the current flowing through the ultrasonic transducer 13 if the phase of the voltage applied to the transducer 13 and the current phase flowing through the ultrasonic transducer 13 are not the same, and may further comprise a cut-and-reset element configured so as to reset the frequency sweep element to a minimum frequency if the frequency change is equal to or exceeds a maximum frequency. Preferably, the minimum frequency is 20 KHz, the maximum frequency is 60 KHz, while the resonance frequency is 44 KHz and the anti-resonance frequency is 46 KHz. Further, the frequency modification is preferably accomplished by means of an increase or a decrease of the input voltage in the frequency sweep element.

[81 ] Further more preferably, the frequency sweep member is formed by an integrator and a voltage controlled oscillator and the ultrasonic device for removing stains in fabrics comprises, in yet another alternate embodiment, a housing comprising a front body 25, a rear body 26 and a power connection plug 27, wherein the power unit comprises the power component 23, the control member 24, and a connector for an electrical cable that electrically connects the power unit to the portable stain removal unit 2, 2'. In such configurations, the power member 23 may comprise a power plate into which electronic components are attached, and the control member 24 may comprise a control plate on which are attached electronic components, the power component 23, and the component of control elements 24 being arranged side by side, or even the power plate and the control plate are arranged face to face, and the electronic components are disposed therebetween, wherein preferably (but not exclusively) the electronic components of the power component 23 protrude out of the power plate to be positioned in void spaces of the control plate, and electronic components of the control member 24 protrude out of the control plate to be positioned in void spaces of the power plate.

[82] In yet another alternative embodiment, the ultrasonic device for removing stains in fabrics comprises a base configured to receive the portable stain removal unit 2, 2', wherein the base may further comprise the power member 23 and the control component 24. In such a

configuration, preferably the portable stain removal unit 2, 2' and the base are electrically connected, and the base may comprise a water reservoir and/or stain removal additives, wherein the stain removal unit 2, 2' and the base are fluidly connected.

[83] In a preferred configuration, the portable stain removing unit 2, 2' has a pen shape.

[84] The present invention overcomes the mentioned problems of the prior art also by means of a method of controlling an ultrasonic device for removing stains in fabrics comprising a portable stain removal unit 2', comprising an ultrasonic transducer 13, the method still comprising the steps of: providing an electrical waveform with a minimum frequency for the ultrasonic transducer 13; determining the phase difference between the voltage applied to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13; and modifying the frequency supplied to the ultrasonic transducer 13 according to the phase difference to block the frequency supplied to the ultrasonic transducer 13 at the resonant frequency.

[85] In such a control method, the step of modifying the frequency supplied to the ultrasonic transducer 13 by means of phase difference determined between the voltage applied to the ultrasonic transducer 13 and the current flowing through the ultrasonic transducer 13 is preferably performed so that if the phase of the voltage applied to the ultrasonic transducer 13 and the phase of the current flowing through the ultrasonic transducer 13 are not equal, the frequency is modified during a step of sweeping a frequency band according to the phase difference between the phase of the voltage applied to the ultrasonic transducer 13 and the phase of the current flowing through the ultrasonic transducer 13, and preferably the step of sweeping the frequency range, upon exceeding a maximum frequency, restarting the device with a minimum frequency. Preferably, as previously explained, the minimum frequency is 20 KHz, the maximum frequency is 60 KHz, while the resonance frequency is 44 KHz and the anti-resonance frequency is 46 KHz.

[86] Obviously, such a control method controls an ultrasonic stain- removing device, as previously explained.

[87] While the invention has been amply described, it is obvious to those skilled in the art that various changes and modifications may be made without such changes being outside the scope of the invention.

LIST OF ELEMENTS OF THE FIGURES

1 , 1 ', 1 " - Ultrasonic stain removing device;

2, 2', 2" - Stain removing unit;

3, 3" - Power unit;

4, 4' - Compartment;

5, 5' - Lid;

6 - Base;

1 1 - Lens;

12 - Ring;

13 - Transducer;

14 - LED board;

15 - Control board of the stain removing unit;

16 - Female cable connector;

17 - Lower part of the body of the stain removing unit comprising a lower part;

18 - Upper body of the stain removing unit;

19 - Male cable connector;

20 - Cable connector;

21 - Left spring;

22 - Right spring;

23 - Power plate;

24 - Power control plate;

25 - Front lower body of the voltage adapter 25;

26 - Rear upper body of voltage adapter 26;

27 - Voltage adapter plug;

91 - Integrator;

92 - Voltage controlled oscillator;

93 - Cut and restart component;

94 - "Duty cycle" component;

95 - Dead time control component;

96 - Drive component; 97 - Voltage change detection circuit;

98 - Current change detection circuit;

99 - Phase comparator;

100 - Ultrasonic transducer;

1 10 - System restart status;

1 1 1 - First Status;

1 12 - Third Status;

1 13 - Fifth Status;

121 - Comparator input;

122 - Signal input;

200 - Button;

201 - Fluid and electrical communication medium;

301 - Electromechanical communication medium;

302 - Electromechanical plug;

600 - Connection portion;

601 - Recess portion;

602 - Labyrinth;

fr - Second Status, resonance frequency;

far - Fourth status, frequency of anti-resonance.