The devices known according to the present state of the art to stimulate the nerves of a person transcutaneously do not allow to generate a certain kind of impulses that appear to be very effective to alleviate pains or to accelerate a rehabilitating and/or healing process.

The invention wants to supply a remedy by presenting a device for the electrical stimulation of the nerves of a person that allows to generate specific electrical impulses with a particular impulse wave.

To this aim, the device, according to the invention, presents means that allow to generate rectangular multi-phase impulses, whereby a first phase shows a voltage with a duration of 5 to 20 milliseconds, while a second phase presents a voltage with a duration of 5 to 20 milliseconds.

For this purpose, said means allow to generate a compensating phase between said first phase and said second phase that has a voltage that is less than one third of the voltage of the first and/or second phase.

The invention is also relating to an electrode for the transcutan electrical stimulation of the nerves that functions with a power source, such as the above mentioned transcutan electrical stimulation device, and that comprises an

electrical conductor, that is to be placed on the skin of a person treated, for transferring electrical impulses and a heating element.

This electrode is characterised in that the heating element consists of an electrical resistor.

According to a particular embodiment of the electrode, according to the invention, this electrode comprises a temperature sensor that co-operates with said power source in order to adjust the temperature of the electrode.

The additional details and advantages of the invention will be clarified in the following specification of several specific embodiments of the device and of the electrode, according to the invention; this specification is given only as an example and does not limit the scope of the claimed protection; the figures used below are related to the attached figures.

Figure 1 is a schematic presentation of a nerve stimulation device, according to the invention, with two electrodes.

Figure 2 is a schematic presentation of an impulse, generated by the nerve stimulation device, according to the invention.

Figure 3 is a schematic presentation of an electronic circuit of the nerve stimulation device, according to a very interesting embodiment of the invention.

Figure 4 is a schematic presentation of an electronic circuit, according to another embodiment of the device, according to the invention.

Figure 5 is a schematic frontal view of the first embodiment of the electrode, according to the invention.

Figure 6 is a schematic cross section according to the line VI-VI from figure 5.

Figure 7 is the schematic longitidunal section of a second embodiment of the electrode, according to the invention.

Figure 8 is a schematic frontal view of the heating part of the electrode, presented in figure 7.

Figure 9 is the more detailed presentation of the electrical circuit, presented in figure 3.

Figure 10 is a schematic presentation of an electrical circuit functioning with the one, presented in figure 9, allowing to adjust the time between successive impulses.

Figure 11 is a more detailed presentation of the electrical circuit, presented in figure 4.

Figure 12 is a schematic presentation of an electrical circuit functioning with the one presented in figure 11, allowing to adjust the time between successive impulses.

The same reference numbers in the different figures are related to the same or analogue components.

The nerve stimulation device 1, according to the invention, as shown in figure 1, is provided with two electrodes 2 and 3 and is connected to the electrical network through plug 3'. These electrodes 2 and 3 are to be placed on the skin of the person treated such that electrical impulses can be administered with the help of the nerve stimulation device.

In figure 2, a schematic multi-phase impulse with a rectangular shape is shown, which appears to be very effective for e. g. the treatment of paralysed or weakened muscles, for the alleviation of the pain or for the acceleration of the healing process.

This impulse presents three phases. A first phase 4 approximates a rectangular form and has a precipitous substantially vertical rising flank 5, whereby the electric voltage rises from 0 to substantially 7 volts. The voltage is held between 6 and 7 volts for about 10 milliseconds. After these 10 milliseconds, the voltage curve has a precipitous, substantially vertical flank 6 and it falls back to 0 volt.

Then, the impulse has a compensating phase 7, which has a small negative voltage peek 8 of about 1,2 volts, taking 5 milliseconds. The compensating phase 7 is e. g. a so-called oscillate of the first phase 4.

Finally the impulse has a subsequent phase 9 that also approximates a rectangular form, with a precipitous, downwards substantially vertical flank 10, whereby the electrical voltage drops from 0 volts to almost-7 volts.

During a period of substantially 10 milliseconds, the electrical voltage is held

between substantially-6 and-7 volts. After these 10 milliseconds, the voltage curve rises immediately via a precipitous, substantially vertical flank 11 until 0 volt.

Good results were achieved when using an impulse with a compensating phase 7with a voltage peek, of which the size is smaller than one third of the voltage of the adjacent phases 4 and 9. The compensating phase 7 takes between 2 and 10 milliseconds.

The voltage of the phases 4 and 9 can vary between 0 and 250 volts, but preferably between 10 and 30 volts. The best results were achieved with a voltage, varying between 20 and 50 volts.

The nerves and muscles of the person treated, are stimulated with a succession of these impulses, through the electrodes 2 and 3, placed on the skin of the person.

The frequency of this succession of impulses is adjustable and is situated in the range of 10 Hz. and 100 Hz, preferably. Good results were achieved by a frequency of substantially 50 Hz. In order to prevent habituation of the impulses, causing the reduction of the desired healing or pain relieving effect, the frequency is modulated in such way, that the time intervals between two impulses is varying.

Figure 3 shows the most important elements of the electrical circuit of the nerve stimulation device, according to a preferred embodiment of the invention, allowing to generate an impulse, such as presented in figure 2. This circuit is equipped with a time-based oscillator 12 with a counter and a quartz crystal with a frequency of 3.2768 MHz. The frequency of this quartz crystal is divided by 213 in order to generate an alternating voltage with a frequency of 400 Hz at the output of the time-based oscillator 12.

This time-based oscillator 12 functions with a divider 13 that divides the said frequency of 400 Hz, by 8 so that a frequency of 50 Hz. is achieved at the output of this divider.

The divider 13 is connected to an element with 2 x 3 parallel switched invertors 14, connected through two outputs with two transistors 15 and 16, connected themselves with an ring kernel transformer 17.

This ring kernel transformer 17 is connected through a potentiometer 18 with two outputs 19 and 20 on which the electrodes 2 and 3 are connected. Between these, a potential difference is generated with a curve in the same form as said impulse. The size of the impulse, generated between both electrodes 2 and 3 can be adjusted with the help of potentiometer 18. The voltage of this impulse can be adjusted, depending on the application, for values between 0 and 250 volts. That way the voltage difference between the phases 4 and 9 is maximum 250 volts.

The exact value of the voltage, generated at the outlets 19 and 20, can be determined on basis of the values that can be read on the oscilloscope-not represented in the figures-functioning with the device, according to the invention.

The use of a ring kernel transformer, not showing an air gap, allows generating a rectangular multi-phase impulse with two rectangular phases, having substantially vertical flanks 5,6,10 and 11, whereby the duration of both these phases is preferably substantially 10 milliseconds.

The time of phases 4 and 9 can vary between 5 milliseconds and 20 milliseconds but a variation between 5 milliseconds and 15 milliseconds is preferable.

Further, the electronic circuit is equipped with a frequency control 21, allowing to modulate the succession of said rectangular multi-phase impulses, in order to avoid habituation, as explained previously.

It is preferable to connect the device, according to the invention, on the mains, when using an alternating current adaptor, transforming a voltage of 230 volts and 50 Hz into a voltage of 24 volts and 1000 mA with a capacity of 24 VA.

Figure 9 shows a more detailed presentation of the electronic circuit, mentioned above. Figure 10 presents an electrical circuit, functioning with the circuit of figure 9, allowing to modulate the succession of the rectangular multi- phase impulses named, in order to avoid habituation.

Another embodiment of the device, according to the invention, allows to generate a rectangular symmetrical impulse with two phases that does not shows the above mentioned compensating phase. Because of this, the impulse has a first rectangular phase, followed by a second rectangular phase.

Figure 4 is the schematic presentation of the electrical circuit, allowing to generate that kind of impulse. This circuit shows a time-based oscillator and a counter 12, functioning with a divider 13 and invertors 14, connected through two outlets, with electrical resistors 22 and two transistors 15 and 16.

Figure 11 shows this kind of digital circuit in detail. This circuit has no ring kernel transformer, as described in the previous embodiment of the device, according to the invention. Figure 12 is the schematic presentation of an electrical circuit, functioning with the circuit of figure 11, allowing to vary the time between the successive impulses.

According to the second embodiment of the device, according to the invention, this circuit allows to generate a rectangular impulse with two phases, between two electrodes that need to be connected on the outlets 19 and 20. The size of the impulse can be adjusted by means of a potentiometer 18, equipped for this purpose.

Figures 5 and 6 show a specific embodiment of an electrode 2, according to the invention. This kind of electrode 2 is connected with for example each of the outlets 19 and 20 of the nerve stimulation device, according to the invention. This electrode 2 needs to be placed on the skin of a person and is highly appropriate for the transcutan electrical stimulation of the nerves.

Electrode 2 has the shape of a disk and contains an electrical conductor for the transfer of electrical impulses. The electrical conductor is connected through an electrical conducting wire 22 with one of the outlets 19 and 20 of a nerve stimulation device 1.

It is established, that electrical impulses penetrate deeper in the skin and the muscular tissue, if the skin of the person treated, is warmed. When warming up the part of the skin to be treated, in combination with the application of the electrical impulses, the sensitivity of the present muscles drops and micro trauma is prevented. The waste products in the muscles are better evacuated and there is no, or just a small amount, of acidity of the muscles.

Therefore electrode 2 is equipped with a heating element. In the embodiment of the electrode 2, presented in figures 5 and 6, this heating element consists of a spiral shaped winded electrical resistor wire 23. Of course this resistor

wire can take any possible shape and measurement, so it can be adapted to the shape and measurement of the electrode 2.

The resistor wire 23 is moulded in a non conducting, circular heating disk, made of synthetics, such as silicone. That way the resistor wire 23 is electrical insulated in relation to the electrical conductor mentioned. The use of silicones ensures that a flexible disk 24 is obtained that thus can fit tight to the skin surface of a person. Because the resistor wire 23 is flexible, has a small diameter and is extending in the disk 24 according to a circle, the heating disk 24 is very supple, notwithstanding the presence of resistor wire 23.

Resistor wire 23 is connected through the wires 26 and 27 with an electrical circuit, not represented in the figures, allowing to heat the resistor wire 23 with a direct current of 20 volts to a temperature of maximum 70°C, preferable. The resistor wire has preferably a resistance of 80 Ohm and a relative small diameter of for example 0.3 mm.

A second circular disk 25 is attached to the heating disk 24, which forms the electrical conductor, responsible for the transfer of electrical impulses to the skin of a person. This second disk 25 is composed, preferably, of silicones, mixed with electrical conducting particles in such a quantity that it is enough to make this second disk 25 electrical conductive. That way, disk 25 forms said electrical conductor and it is connected with wire 22.

The second disk 25 of the electrode 2 is placed on the skin of an person, whereby the heat produced by the resistor wire 23 is warming up the skin of the person through the second disk 25.

The electrode, according to the invention, is provided with a temperature sensor 28, co-operating with the nerve stimulation device through wires 29 and 30. It is now possible to adjust the current of the resistor wire 23 in function of the temperature of electrode 2, measured with the temperature sensor 28. In an efficient way, the temperature of electrodes 2 and 3 is set in advance, by means of the nerve stimulation device, whereby the latter adjusts the current, supplied to the resistor wire 23, in function of the temperature, measured by means of the temperature sensor 28 and this in order to achieve or maintain the temperature set.

In order to prevent the overheating of electrodes 2 and 3, which could cause injuries or damages to the skin, the temperature sensor 28 co-operates with a switch element, such as a switch, ensuring that the current supplied to the heating element 23 is cut in case the temperature of at least one of the two electrodes 2 or 3 is higher than 85°C. Preferably, the current supply is cut when the temperature of the electrodes rises above 70°C.

The switch element can, in another embodiment of the electrodes, according to the invention, be formed of a heat sensitive diode that is provided in the electrodes and that is connected in series with said heating element 23. In case the temperature of the electrode rises to for example 70°C or 85°C, the heat sensitive diode will cut the electrical current supply, warming up the heating element 23. So the switch element becomes a temperature sensor aswell.

Preferably, the silicone used is temperature-resistant to up to substantially 200°C.

A different embodiment of the electrodes, according to the invention, is presented schematically in figures 7 and 8. These electrodes comprise a heating element 31 with a flat surface plate, on which a heat resistor wire 23 with a resistance of, for example, 80 Ohms, is attached, as presented in figure 8.

An electrical conductor 25 in the form of a shell 32, preferably made of tin, encloses the heating element 31. This electrical conductor 25 is connected through wire 22 with one of the outlets 19 and 20 of the nerve stimulation device. An electrical insulation layer 33, made of synthetics, is placed between the shell 32 and the heating element 31. This electrical insulation layer 33 is preferably made of polytetra-fluoroethylene, known under the trade name'Teflon'.

Said shell 32 transfers the electrical impulses, generated by the nerve stimulation device, when electrodes 2 and 3 are placed on the skin of a person.

The heating element 31 shows a temperature sensor 28, connected with the nerve stimulation device through the electrical wires 29 and 30 in order to adjust the temperature of the electrodes.

To prevent that the temperature of electrodes 2 and 3 would rise above for example 70°C or 85°C, the heating element is provided with a heat sensitive diode 34, connected in series with said resistor wire 23. Thus, the electrical

current in this resistor wire 23 is cut, when the temperature of the electrode rises above for example 70°C or 85°C.

The invention is of course not limited to the embodiments of the device and the electrodes, mentioned above and presented in the figures, according to the invention. There is for example a possibility to connect more than two electrodes with the outlets of the device, according to the invention. It is also possible to provide the nerve stimulation device with multi-functional screen, whether or not touch sensitive, or light emitting diodes in order to be able to read certain variables, such as the duration of the electrical frequency controlled impulses, the size of the impulses and the temperature of the electrodes. It is thus possible to adjust the values of these variables in function of the person treated.