CA2660083A1 - Portable device for generating a magnetic field for magnetic field therapy - Google Patents

Abstract

The portable device (1) is intended to be used to generate a magnetic alternating field for magnetic field therapy. Said device comprises at least one permanent magnet (5) and a mechanical drive (6) by means of which the at least one permanent magnet (5) can be made to move in a cyclical manner. The at least one permanent magnet (5) and the drive (6) are designed such that the magnetic alternating field which is generated by the cyclical movement of the at least one permanent magnet (5) has a single frequency.

Description

Portable device for generating a magnetic field for magnetic field ther-apy The invention relates to a portable device for generating a magnetic alter-nating field for magnetic field therapy.

There are known electromagnetic therapy devices in which the generated electromagnetic fields produce a systemic non-specific and supporting curative effect. The known devices can be used, for example, to promote the metabolism or blood circulation. Nevertheless, these devices usually allow treatment merely of a comparatively large part of the body and oper-ate using relatively weak fields. Purposeful treatment of small affected body regions using sufficiently strong fields which also exert therapeutic effects on functionally impaired individual cells is, on the other hand, not possible with the known devices.

The object of the invention is therefore to disclose a device of the type de-scribed at the outset that is suitable for purposeful treatment of small body regions.
To achieve this object, a device corresponding to the features of claim I is disclosed. The device according to the invention comprises at least one permanent magnet and a mechanical drive by means of which the at least one permanent magnet can be caused to move cyclically, wherein the at least one permanent magnet and the drive are configured in such a way that the magnetic alternating field generated by the cyclic movement of the at least one permanent magnet is monofrequent.

The magnetic alternating field which can be generated using the device according to the invention is therapeutically effective. The fact that the de-vice is limited to, in particular, a single frequency means that it is suitable, above all, for cellular treatment. There is therefore achieved a therapeutic effect on preferably individual cells, in particular on cells functionally im-paired as a result of illness. It was found that the cellular therapeutic effects are highly frequency-dependent. In particular, the effects are produced merely within very narrow frequency windows. The therapeutically effec-tive field generated by the device according to the invention is therefore a substantially monofrequent magnetic alternating field which therefore has, in particular, a sine-like time characteristic and preferably no harmonic waves.

According to the law of induction, the monofrequent magnetic alternating field thus generated produces in the tissue and, in particular, at the cell to be treated an electric alternating field which is also monofrequent and can act directly on cells by intervening in the cellular signal transduction. The cell differentiation and the immunological behavior of cells can thus be influenced in the manner of functional standardization and regeneration.

This allows customized electromagnetic therapies against specific condi-tions caused by impaired cell function with, for example, accompanying inflammation. Examples of conditions which can be treated in this way include wound healing disorders and inflammatory skin diseases.

A magnetic alternating field which is generated by the device according to the invention and is located, in particular, in the low-frequency range may therefore be used highly effectively for therapeutic purposes. The magnetic alternating fields induce electric fields, the intensities of which are prefera-bly above action thresholds for cell biological differentiation and regenera-tion processes and immunological effects. The magnetic field intensity or the magnetic flux density therefore preferably also exceeds corresponding thresholds. Magnetic field therapy with magnetic alternating fields is used, in particular, in inflammation processes and impaired cell functions on which these processes are based, for promoting the metabolism, increasing blood circulation and alleviating pain, in inflanunations of the bones and joints, for accelerated healing of wounds and ulcers, and also in neurologi-cal diseases such as polyneuropathies and neurogenerative diseases.

The device according to the invention is preferably configured in such a way that when the device is applied to the surface of a body to be treated, the magnetic flux density which is produced by the device within a certain depth of the tissue exceeds the action thresholds required for the cell bio-logical processes.
It has been found that moving permanent magnets can advantageously be used for generating sufficiently strong magnetic altemating fields having, for example, magnetic flux densities which are within the milli-Tesla range within the body to be treated and cause in the tissue correspondingly strong electric fields which exceed the aforementioned action thresholds. Perma-nent magnets have considerable advantages in terms of space over electric coils which are, in principle, also suitable for generating magnetic fields.
Coils configured for high electric currents are bulky. A high number of turns which may be necessary further increases the amount of space re-quired. The movable permanent magnets provided in the device according to the invention require much less space by comparison, so they may be incorporated more easily in a portable device having merely limited instal-lation volume.

Permanent magnets having a volume of, for example, just two cubic centi-meters can produce at their poles magnetic flux densities of several hun-dred mill-Teslas producing, on application to a person's body even several centimeters such as, for example, four centimeters in depth, sufficient magnetic flux densities of a few milli-Teslas producing during movement sufficient electric field strengths for surpassing the aforementioned electric action thresholds.

For an equivalent effect, i.e. on provision of a magnetic alternating field which is, in particular, sufficiently strong to surpass the action thresholds provided in the tissue, moving permanent magnets can be used to provide a much more compact and lighter device than is achievable using electrically operated coils.

A preferred embodiment of the invention provides for the at least one per-manent magnet to move circularly or cyclically linearly. Superimposition of cyclic circular and linear movements is also possible. Particularly bene-ficial is the embodiment in which the at least one permanent magnet can be caused to move circularly.
Whereas the device according to the invention may, in principle, have just one permanent magnet, so on movement thereof at a site of action the maximum flux density brought about by the permanent magnets fluctuates, in a preferred embodiment there are provided at least two, in particular four or eight, permanent magnets. The polarity of the flux density may in this case be reversed, so the difference in flux density is doubled over that obtained if permanent magnets having identical polarity are used. A pre-ferred development of the invention therefore provides for adjacent perma-nent magnets to be arranged so as not to be aligned in their direction of action (direction of connection of north and south poles). Adjacent perma-nent magnets may, in particular, be oriented with a differing, in particular an opposing, direction of action (connection from north to south pole). Al-though the permanent magnets may in principle be polarized in the radial direction, i.e. the line connecting the north to the south pole is oriented ra-dially, a preferred embodiment provides for the permanent magnets to be polarized in the axis-parallel direction. The permanent magnets are in this case in the form of planar plates having a thickness of a few millimeters and polarized in the thickness direction, i.e. the bottom and top of the plates form the two poles. This has the advantage that the magnetic field is more intensively active in the depth of the tissue than if the permanent magnets were polarized longitudinally. The arrangement comprising four sector magnets alternating in this manner, modified in accordance with the thickness polarization, produces in the tissue almost perfect sinusoidal os-cillations of the magnetic flux density. The disc comprising the four per-manent magnets generates two complete sinusoidal oscillations per revolu-tion. In other words, for a given or desired flux density monofrequency, the disc has to rotate at half the frequency (i.e. UpS).
If more than four sectors are arranged on the disc, a higher flux density monofrequency is generated per revolution. If magnet shapes other than segment of a circle or sector-shaped (for example rectangular magnets) are chosen, the differing tangential speeds between the edge of the disc and the centre produce in the generated magnetic alternating field, in addition to the basic oscillation, also harmonic waves thereof; this can be highly bene-ficial for certain therapeutic applications.

The permanent magnets may differ in shape. The permanent magnets may be cuboid-shaped or cylindrical. Especially if the magnets are arranged on a circular disc, a preferred embodiment provides for them to be in the form of partial sectors. Especially beneficial is a variation in which the at least one permanent magnet is in the form of a sector of a circle or an annular sector of a circular ring. A merely approximate sector of a circle shape is obtained if the tip of the sector of a circle is omitted in the central region, for example for manufacturing-related reasons. The desired monofre-quency of the magnetic alternating field can be generated particularly ef-fectively using an (annular) sector of circle-shaped permanent magnets.
The same advantages are obtained if at least two, in particular four or eight, sectors of circle-shaped or annular sectors of circle-shaped permanent magnets are provided and are arranged on a circular base so as to be dis-tributed uniformly in the circumferential direction thereof. Also arranged on the circular base in the circumferential direction are permanent magnets which are arranged adjacently to one another and preferably have opposing polarity (i.e. having an opposing direction of magnetic action). For generat-ing a magnetic alternating field which is as monofrequent as possible, it is also beneficial for there to be provided preferably between two permanent magnets arranged adjacently to each other in the circumferential direction a respective unoccupied empty segment having substantially the same sector of a circle shape or annular sector of a circle shape as that of the permanent magnets. The empty segments therefore have substantially the same sur-face geometry, i.e. the same surface shape and the same surface content, as the permanent magnets.

Provision is also preferably made for the at least one permanent magnet to have at its magnetic poles a magnetic flux density of greater than 10 mT
and less than 2,000 mT, in particular of about 1,400 mT. This ensures that the induced electric fields in the tissue and at the cells are large enough to exceed the action thresholds. If the permanent magnets are configured ap-propriately, the flux density of the inducing magnetic field is at least two milli-Teslas (mT) even at the site of action itself within the tissue. In the event of a cellular defect in a joint, this site of action is, for example, at a joint depth of about 3 cm.

The cyclic movement of the permanent magnets is preferably imposed by an electric motor, in particular a DC motor. This allows the motion re-quired for generating the alternating fields to be produced using little power. The power source provided may be a battery, a rechargeable battery or else a terminal for an external power supply. A gear is preferably pro-vided between a movable carrier carrying the permanent magnet or mag-nets, such as a rotatably mounted disc, and the driving motor, as a result of which a frequency of revolution and therefore a desired alternating fre-quency of the magnetic field can be brought about by a suitable gear transmission means even if the rpm of the electric motor is set.

In order to minimize or even completely to eliminate mutual interference between the rotating permanent magnets and the drive, which is preferably also based on a principle of (electro)magnetic action, provision is also preferably made to set the drive and the at least one permanent magnet apart from each other at least to the extent that a drive magnetic field pro-duced by the drive has at the location of the at least one permanent magnet a magnetic flux density which is less by a factor of 100,000 (= 105) than the magnetic flux density of the at least one permanent magnet at its mag-netic poles. A distance thus selected is advantageous also with regard to the generation of a magnetic alternating field which is therapeutically effec-tive, i.e. as monofrequent as possible.

According to a preferred embodiment, provision is made for at least two cyclically movable permanent magnets each to be accommodated in its own magnet housing and to be connected to a central housing using a flexible holder such as, for example, a swan-neck, the common control electronics and the common power supply being accommodated, in par-ticular, in the central housing. Each magnet housing receives, in particular, not only the permanent magnet but also the rotating mounting plate for the permanent magnet, the light barrier and the motor drive for the plate. This preferred embodiment allows larger body areas easily to be treated using magnetic alternating fields.

Preferred embodiments of the method provide for the flux density frequen-cies to be varied continuously or discontinuously, the flux density frequen-cies being varied, in particular, with a partial cycle time of a few minutes, preferably of between 0.5 and 2.5 minutes. The total cycle time is equal to the sum of the partial cycle times. Preferably, the total cycle time is at most 10 minutes. A preferred value of the total cycle time is 2.5 minutes. The flux density frequencies may be varied, for example, between 4 and 12 Hz, for example discontinuously as flow density monofrequencies from 4 via 6, 8, 10 Hz to 12 Hz and, in particular, back again to 4 Hz. The field condi-tions are then substantially monofrequent at all times. The flux density has in this case merely a single frequency component which is at the aforemen-tioned respective flux density monofrequency. Appropriate programming of the control processor therefore allows customized treatment sequences or cycles to be generated for various therapeutic applications.

According to a further preferred embodiment, the generated therapeutically active magnetic alternating field has a flux density monofrequency which can be adjusted in the range between 5 Hz and 25 Hz. In this low-frequency range, a large number of cells are particularly receptive to thera-peutic electromagnetic influencing. Flux density monofrequencies of, in particular, about 6 Hz thus stimulate, for example, the formation and re-lease of biochemical mediator substances which are important for wound healing.

Provision is also preferably made for the drive to be connected to a control unit and the control unit to be configured for stabilizing a flux density monofrequency, which may in particular be predetermined, of the gener-ated magnetic alternating field. This rotational speed or frequency stabili-zation means checks and, if necessary, ensures using an appropriate subse-quent control means that the generated magnetic alternating field is indeed as monofrequent as possible. Preferably, the control unit and the drive acti-vated thereby are configured to generate the magnetic alternating field in succession and each for a specific partial cycle duration having a flux den-sity monofrequency differing from the preceding partial cycle duration.
The beneficial treatment sequences or cycles referred to above may thus be produced very easily. For purposeful cell treatment, the partial cycle dura-tion should be preferably at least 30 seconds, for the cell requires about 7 to 10 seconds to adjust to the flux density monofrequency. On operation at just a single flux density monofrequency, the partial cycle duration is equal to the total cycle duration (for example, preferably about 2.5 minutes). If the partial cycle duration is, in particular, in the range between 30 seconds and 2.5 minutes, the cell advantageously does not yet become accustomed to the respective flux density monofrequency. Such accustomization is likely to become intensified, in particular, from a partial cycle duration of 10 minutes and more. Providing a longer partial cycle duration reduces the cellular treatment efficiency.

The invention and its advantageous embodiments have been described hereinbefore with reference to a device according to the invention. How-ever, the invention equally relates to a method for generating a magnetic alternating field for magnetic field therapy, which method has substantially the same features and advantages as the device according to the invention.
The method according to the invention can, for example, be carried out using the device according to the invention. For the method according to the invention, there may also be disclosed advantageous embodiments cor-responding substantially to those of the device according to the invention.

Further advantages and features of the invention will emerge from the claims and from the following description in which embodiments of the invention will be described in detail with reference to the drawings. They show:

Fig. I a schematic view of an embodiment of a portable device for generating strong therapeutic alternating fields, Fig. 2 a carrier, equipped with permanent magnets, for the device ac-cording to Fig. 1, Fig. 3 a section along III-III from Fig. 2, and Fig. 4 a circuit diagram of the electronics of the device according to Fig. 1.

In Fig. 1 to 4, corresponding parts are provided with the same reference numerals.

Fig. 1 shows an embodiment of a portable device I for generating highly therapeutically effective alternating fields. The schematic illustration ac-cording to Fig. 1 is restricted to the basic features. In the illustrated em-bodiment, the device 1 has a housing 2 in which a circular disc-shaped car-rier 4 is mounted so as to be able to rotate about an axis A. The carrier is mounted using a smooth-running bearing 3 which is merely indicated in Fig. 1 such as, for example, a ball bearing. In the illustrated embodiment, the carrier 4 has four annular sectors of circle-shaped permanent magnets 5 which are arranged on the carrier 4 at angles of 90 relative to one another and so as to be distributed uniformly in the circumferential direction of the carrier 4. In the embodiment shown in Fig. 1 and 2, the annular sectors of a circle-shape of the permanent magnets 5 is determined by an external di-ameter DA of about 6 cm and by an internal diameter D, of about 1 cm. The recess, which is located in the centre and determined by the internal diame-ter Di, is used to receive the axis A. The permanent magnets 5 each have a thickness of about 6 mm.

Permanent magnets 5 adjacent to one another in the circumferential direc-tion of the circular disc-shaped carrier 4 have opposing polarity, the abso-lute direction of the magnetic north/south polarization of the permanent magnets 5 extending in the direction of the thickness of the plate-like per-manent magnets 5 and thus parallel to the direction of the axis A. The per-manent magnets 5, which in the illustration according to Fig. 1 and 2 are arranged at the top and bottom, have their respective magnetic south pole on the visible upper side, whereas the two other permanent magnets 5, i.e.
those arranged laterally to the left and right in Fig. 1 and 2, have their re-spective magnetic north pole on the visible upper side. The magnetic orien-tation of tangentially adjacent permanent magnets 5 therefore alternates.

Tangentially adjacent permanent magnets 5 do not directly adjoin one an-other. Provided between them is a respective unoccupied empty segment 5a which has substantially the same geometrical shape, i.e. the shape of an (annular) sector of a circle, and the same dimensions as the permanent magnets 5. Owing to this geometrical shape and the aforementioned ar-rangement of the permanent magnets 5 and the empty segments 5a, there is generated on uniform rotational motion of the carrier 4 a magnetic alternat-ing field which is substantially monofrequent. The magnetic flux density of the magnetic alternating field therefore has merely a single flux density monofrequency. The magnetic alternating field thus generated is almost perfectly sinusoidal and has virtually no harmonic waves. It can therefore be used particularly effectively for the treatment of individual cells.

The carrier 4 carrying the permanent magnets 5 is driven by an electric mo-tor 6 via a gearing connection 7 which, in the illustrated embodiment, is a drive belt. The drive belt acts, on the one hand, on a pinion 6a of the elec-tric motor 6 and, on the other hand, on a disc 4a which is provided with a circumferential groove and rigidly connected to the carrier 4. The gearing connection 7 allows a lateral or radial distance d to be provided between the external circumferential line of the rotating permanent magnets 5 and the driving electric motor 6. Advantageously, this distance is sufficiently large in order substantially to rule out mutual magnetic interference. De-pending on the application and specific embodiment of the portable device 1, the values of the distance d are a few cm, preferably between 1 cm and 3 cm.

The electric motor 6 is preferably a DC motor which is electrically pow-ered by batteries or rechargeable batteries arranged in a corresponding compartment 8.

The circular disc-shaped carrier 4 has on its external circumference a large number of radial slots 4b with which there is associated a light barrier 9 secured to the housing.

Control electronics 10a, indicated merely schematically in Fig. 1, of the device 1 are located on a printed circuit board 10.

The voltage of the electric motor 6 is in the lower voltage range of 24 V or less, preferably just 3 V. The power consumption is therefore in the lower wattage range, preferably below 1 watt, in the specific embodiment about 0.4 W. The rotational frequency of the carrier 4 is in the lower hertz range, preferably below 100 Hz and in particular from 2 to 6 Hz, so, in the case of the four permanent magnets 5 in the illustrated arrangement having alter-nating magnetic orientation (= polarity), the frequency of the field of mag-netic action is doubled to 4 to 12 Hz.

The magnetic field strength of the permanent magnets 5 is, at their poles on the top or bottom of the plate, in the Tesla range or therebelow and should on the outside of the housing 2 be substantially no greater than 300 milli-Teslas, preferably at most 250 milli-Teslas (mT). In the embodiment, the permanent magnets 5 are made of a sintered NdFeB material which is magnetized after the sintering process. For the purposes of sintering, the starting material, which is for example still in powdered form, is introduced into a sintering mould which imparts the desired annular sector shape to the permanent magnets 5 to be produced. After magnetization, the magnetic flux density at the top or bottom of the permanent magnets 5 thus produced is approximately 1,400 mT.

The weight of a device 1 according to the invention is less than 500 g, preferably in the range of about 200 g.

Fig. 2 is an enlarged detailed view of the carrier 4 equipped with annular sectors of circle-shaped permanent magnets 5, the disc 4a provided for driving the carrier 4 having been omitted for the sake of clarity. Also, of the axis A, merely the central centre line, about which the rotational movement is carried out, is indicated. According to the sectional view shown in Fig. 3, the permanent magnets 5 are preferably arranged in cone-sponding recesses in the carrier 4 and fixed therein.

Fig. 4 is a circuit diagram of a preferred embodiment of the control elec-tronics 10a of the device I according to the invention.

There is provided a power supply 11, such as for example a battery or a rechargeable battery, which supplies a voltage U via earth M. The connec-tions, provided in the control electronics l0a at various locations, to the maximum or standard voltage U or to earth M are denoted by the same symbols throughout the circuit diagram.

The rotational speed of the electric motor 6 is controlled in the above-described manner by a programmable microcontroller 12, which is clocked by an oscillating crystal 12a, and by means of an electronic switch 13. The power driving the electric motor 6 is also provided by the power supply 11.
The microcontroller 12 monitors and controls the rotational movement of the carrier 4 brought about by the electric motor 6. The microcontroller carries out a rotational speed and frequency stabilization and thus a corre-sponding adjustment to ensure that the generated magnetic alternating field is as monofrequent as possible.

For monitoring and if necessary subsequently adjusting the rotational speed of the electric motor 6 and/or, above all, the carrier 4, there is provided a rotational speed optical detector which comprises the above-mentioned light barrier 9 and transmits its measured values to the microcontroller 12.

On detection of deviation from the currently provided desired rotational speed, the microcontroller 12 then correspondingly corrects the rotational speed of the electric motor 6.

The device I is switched on and off via an actuatable switch 14. Further-more, the circuit has both a visual output 15 and a sound output 16 by which, for example, the switching-on and/or the readiness for use of the device I and the termination of a treatment process can be output visually and/or by sound. The visual output 15 may, in particular, be in the form of a light-emitting diode which flashes throughout operation.

The microcontroller 12 is connected to an interface 17 via which the mi-crocontroller 12 can be programmed.

Claims (9)

1. Portable device for generating a magnetic alternating field for magnetic field therapy comprising a) at least two sectors of circle-shaped or annular sectors of circle-shaped permanent magnets (5) which are arranged on a circular base (4) so as to be distributed uniformly in the circumferential direction thereof, and b) a mechanical drive (6) by means of which the permanent magnets (5) can be caused to move cyclically, c) wherein the permanent magnets (5) and the drive (6) are configured in such a way that the magnetic alternating field generated by the cy-clic movement of the at least one permanent magnet (5) is monofre-quent, and d) a respective unoccupied empty segment (5a) having substantially the same sector of a circle shape or annular sector of a circle shape as the permanent magnets (5) is provided between two permanent magnets (5) arranged adjacently to each other in the circumferential direction.

2. Device according to claim 1, characterized in that the at least one per-manent magnet (5) can be caused to move circularly.

3. Device according to claim 1, characterized in that four or eight sectors of circle-shaped or annular sectors of circle-shaped permanent magnets (5) are provided.

4. Device according to claim 1, characterized in that permanent magnets (5) arranged on the circular base (4) adjacently to one another in the circumferential direction have opposing polarity.

5. Device according to claim 1, characterized in that the generated thera-peutically active magnetic alternating field has a flux density monofre-quency which can be adjusted in the range between 5 Hz and 25 Hz.

6. Device according to claim 1, characterized in that the drive is connected to a control unit (10a) and the control unit (10a) is configured for stabiliz-ing a flux density monofrequency of the generated magnetic alternating field.

7. Device according to claim 6, characterized in that the control unit (10a) and the drive (6) activated thereby are configured to generate the mag-netic alternating field in succession and each for a specific partial cycle duration having a flux density monofrequency differing from the preced-ing partial cycle duration.

8. Device according to claim 1, characterized in that the at least one per-manent magnet (5) has at its magnetic poles a magnetic flux density of greater than 10 mT and less than 2,000 mT, in particular of about 1,400 mT.

9. Device according to claim 1, characterized in that the drive and the at least one permanent magnet (5) are set apart from each other at least to the extent that a drive magnetic field produced by the drive (6) has at the lo-cation of the at least one permanent magnet (5) a magnetic flux density which is less by a factor of 100,000 than the magnetic flux density of the at least one permanent magnet (5) at its magnetic poles.