Patent Description:
Devices and methods for generating magnetic pulses have been used for a long time for medical and aesthetic treatments. To this end, applicators are used, in which electrically conductive coils are provided. Electric current, variable over time, flows in the coils and generates variable magnetic fields. By putting the applicators onto the patient's body or close thereto, the variable magnetic fields enter the patient's body and induce in it electric currents having an effect similar to that of electro-therapy treatments.

Magnetic field treatments may have both aesthetic and medical purposes, for example stimulating muscle in rehabilitation, or the like. Magnetic field treatments may be effectively used in medical applications such as fat reduction, thus lessening the risks connected to pre-obesity and obesity, with particular reference to the abdominal region. With reference to the medical sector again, magnetic field treatments may be effectively used for strengthening the pelvic floor muscle in in the treatment of urinary incontinence. Magnetic therapy may be also used in the aesthetic sector for body shaping.

The electric currents induced in biological tissues by the magnetic fields cause, among other things, neural excitation and stimulation of muscle contractions. The intensity thereof depends on the magnetic flow density and the law of change over time of the magnetic flow.

The treatment aims at achieving a muscle stimulation of such intensity, frequency and repetitions to cause a muscle supramaximal contraction, i.e. level and duration of the contraction significantly higher than the physiological ones (maximal voluntary contractions). In this way, muscle stresses and physiological workload increase, requiring the muscle to adapt to these extreme conditions by deeply sculpting its inner structure through hypertrophy and hyperplasia processes resulting in an increase of muscle volume and tone.

Magnetic therapy applicators (coils) shall be therefore able to generate a pulsed magnetic field, whose single pulse shall have such a duration to induce neuromuscular stimulation. The pulse duration is typically comprised between <NUM> and <NUM>. Moreover, the magnetic therapy applicator (coil) shall be able to generate the pulses with such an intensity as to penetrate deeply, reaching the muscle or tissue region to be treated, onto which neuromuscular stimulation shall be induced.

Therefore, as the magnetic field intensity and spatial distribution also depend on the coil geometry, typically different coils are manufactured according to the type of region/tissue to be treated and to the depth to be achieved. In addition to achieve the neuro-stimulation threshold in the area to be treated and at the required depth, the magnetic therapy applicator shall be also able to support the generation of magnetic field pulse sequences of variable frequency, adapted to induce muscle supra-maximal contractions or the contractions required by the specific treatment. These contractions, and therefore the pulses generating them, shall follow defined patterns, which typically involve also changes in the magnetic field intensity, because, usually, during a same treatment muscle contraction and relaxation phases shall alternate with one another. Typically, the maximal frequency used is approximately <NUM>. The overall duration of the treatment, intended as sequences of patterns of magnetic field pulses of variable frequency and intensity, typically varies from <NUM> minutes to <NUM> minutes, depending on the patient.

Magnetic therapy applicators comprise a housing with an outer wall, which defines a contact surface, i.e. an application surface to be applied to the patient. At least one electrically conductive coil is arranged in the housing for generating a magnetic field. A refrigerating device shall be associated with the applicator, in order to avoid overheating of the coil and above all thermal injuries to the patient. Some applicators are therefore equipped with a fan generating a refrigerating airflow that removes heat from the applicator whilst current passes in the coil.

In order to have quick results with a few treatments, the treatments shall advantageously provide for prolonged steps of supramaximal contraction and high duty cycles. This can be achieved only by applying sequences of magnetic field pulses of high intensity and frequency. Due to these prolonged phases, the coil is passed by high intensity currents for most treatment time, with consequent heat generation due both to the Joule effect and the proximity effect of the magnetic field generated by the same coil.

Therefore, a hindrance to the prolonged application of high currents is the risk of burns to the patient due to the heat generated by the coil.

<CIT> discloses a magnetic therapy applicator comprising a housing with an outer wall, which defines an application surface to be applied to a patient, and in which at least one electrically conductive coil is housed for generating a magnetic field. The coil is so installed in the housing that a gap is formed between the coil face facing the patient and the application surface to be applied to the patient, and air forced circulation for heat removal is generated in this gap by a fan. This refrigerating system is poorly efficient.

<CIT>, <CIT>, <CIT> and <CIT> disclose further application devices. These devices are poorly efficient too as regards heat removal during treatment.

There is therefore a need to improve magnetic therapy applicators in order to allow efficient treatments in short time without the risk of thermal injuries to the patient or thermal damages to the devices contained in the applicator.

The present disclosure relates to an applicator for magnetic therapy comprising a housing with an outer wall, which defines an application surface to be applied to a patient, and in which at least one electrically conductive coil is housed for generating a magnetic field. In order to improve its features, the applicator is also provided with an outer shell forming the outer wall and constituting the application surface, and an inner shell forming a seat for housing the coil. The inner shell comprises a bottom wall facing the inner surface of the outer shell and, more precisely, facing the outer wall defining the application surface of the outer shell.

A gap is advantageously formed between the bottom wall of the inner shell and the outer wall of the outer shell for thermally insulating the coil and the application surface from each other.

The use of an outer shell and an inner shell makes the production of the applicator simpler, as it is possible to provide, in the inner shell, the magnetic field generating components, the temperature controllers, for instance an NTC resistance or other temperature sensor, as well as, if necessary, a refrigerating device. These components may be resin-encapsulated to form a single block to be inserted in the outer shell. Resin-encapsulation gives the coil housing the necessary mechanical stability, also ensuring adequate electrical insulation and good thermal conductivity of heat generated in the coil. The outer shell may be closed by a closing shell.

Moreover, the gap between the outer wall of the outer shell forming the application surface, and the bottom wall of the inner shell constitutes an efficient thermal barrier for reducing heat transfer from the coil to the application surface and, therefore, to the patient. In this way, very intense magnetic fields can be generated, thus making the treatment effective and quick, avoiding thermal injuries to the patient and making the treatment more pleasant.

The applicator further comprises a refrigerating device.

Specifically, the refrigerating device comprises a fluid circulating system with at least one refrigerating duct adapted to circulate a refrigerating fluid, for example water. However, the refrigerating fluid is preferably an electrically low conductive fluid, in order to avoid generation of parasite currents in the coils formed by the refrigerating duct, which parasite currents are able to generate magnetic fields opposing the variable magnetic field generated by the coil.

Typically, high dielectric strength oils (generally utilized for cooling of transformers) are used, or alternatively demineralized water, wherein, during operation, conductibility control systems ensure low conductibility values.

The refrigerating duct is suitably arranged between the coil and the application surface, for more effective refrigerating of the applicator area touching the patient.

In particular, the refrigerating duct may be arranged between the coil and an outer surface of the bottom wall of the inner shell, preferably in a seat or groove formed in the surface of the bottom wall facing the coil.

In particularly advantageous embodiments, the refrigerating duct is spiral shaped, lying on a plane parallel to the bottom surface of the inner shell and housed in a spiral groove formed in the thickness of the bottom wall and open towards the coil.

In alternative embodiments, ducts or channels may be provided in the thickness of the bottom wall of the inner shell, for example by additive manufacturing.

In the thermal insulation gap formed between the outer wall of the outer shell and the bottom wall of the inner shell, spacing elements are provided, which define the height of the gap, i.e. the distance between the surface of the outer wall facing the inner shell and the surface of the bottom wall of the inner shell facing the outer wall of the outer shell.

In order to reduce the contact between the outer shell and the inner shell at the gap, the spacing elements can be approximately dot-shaped, i.e., they can have the shape of prisms, cones or cylinders with a small cross section. This allows reducing conductive heat transfer between the inner shell and the outer shell by realizing a thermal break between the inner shell and the outer shell.

If the inner shell comprises a groove for housing the refrigerating duct, the spacing elements are preferably arranged at the groove, where the temperature is lowest due to the refrigerating fluid. This further reduces heat transfer.

Further features and embodiments of the applicator will be described below with reference to the attached drawing.

The invention will be better understood by following the description below and the attached drawing, showing a non-limiting embodiment of the invention. More specifically, in the drawing:.

<FIG> is an outer axonometric view of an applicator <NUM>. In the illustrated embodiment, the applicator <NUM> comprises an outer shell <NUM>, which defines the application surface to be applied to the patient, and a covering shell <NUM>. The outer shell <NUM> and the covering shell <NUM> form a closed housing or casing, in which one or more electromagnetic coils are provided, i.e. coils adapted to generate a magnetic field when current flows therein, and a refrigerating device. The surface of the applicator to be applied to the patient is indicated with reference number 3A and will be briefly referred to below as application surface.

In the embodiment illustrated just by way of non-limiting example, the applicator <NUM> comprises a handle <NUM> that, in this case, is an integral part of the covering shell <NUM>.

An inner shell <NUM> is provided inside the volume formed between the outer shell <NUM> and the covering shell <NUM>; the inner shell <NUM> forms a support for receiving a coil <NUM>, made of electrically conductive material, and a refrigerating device <NUM> , which in the illustrated embodiment consists of a refrigerating circuit configured to circulate a refrigerating liquid. In the illustrated embodiment, the refrigerating circuit comprises only one refrigerating duct <NUM> forming multiple turns, as detailed below. The reference numbers 13A, 13B (see in particular <FIG>) indicate the power supply terminals of the coil <NUM>, whilst the numbers 15X, 15Y indicate the inlet and outlet of the refrigerating duct <NUM>.

In the illustrated embodiment, the refrigerating duct <NUM> is constituted by a tube manufactured separately from the inner shell <NUM> and inserted in a seat, for example a groove, provided in the bottom wall of the inner shell <NUM>. However, different embodiments are also possible. The bottom wall may be for example comprised of two mutually coupled components, between which the refrigerating duct <NUM> is formed. In further embodiments, the refrigerating duct may be formed, by additive manufacturing, in the bottom wall of the inner shell <NUM>.

The outer shell <NUM> comprises an outer wall <NUM>, which defines the application surface 3A. A side wall <NUM> extends from the outer wall <NUM>, approximately orthogonally to the application surface 3A; the side wall <NUM> surrounds the inner shell <NUM> and is coupled to the covering shell <NUM>.

The inner shell <NUM> has an overall approximately cylindrical shape and comprises an annular bottom wall <NUM>, from the outer edge whereof an approximately cylindrical first perimeter wall <NUM> extends, approximately orthogonally to the bottom wall <NUM>. An approximately cylindrical second perimeter wall <NUM>, substantially coaxially with the first perimeter wall <NUM>, extends from an inner edge of the bottom wall <NUM>.

The walls <NUM>, <NUM>, <NUM> define an annular seat <NUM>, where the coil <NUM> and the refrigerating device <NUM> are housed as described below. The coil <NUM> and the refrigerating device <NUM>, i.e. the refrigerating duct <NUM>, are advantageously resin-encapsulated in the annular seat <NUM>. Resin-encapsulation is not shown in the attached drawing for greater clarity.

As mentioned above, in the illustrated embodiment the refrigerating circuit constituting the refrigerating device <NUM> comprises a single refrigerating duct <NUM>, which forms a spiral, lying on a plane parallel to the bottom wall <NUM>, and is partially embedded in the thickness of the bottom wall <NUM>. In the illustrated embodiment, as shown in particular in the detail of <FIG>, a seat is provided in the inner surface of the bottom wall <NUM> for housing part of the refrigerating duct <NUM>. The seat is formed by a spiral-shaped groove 25A, where the turns 15A of the refrigerating duct <NUM> are housed. The thickness of the bottom wall <NUM> is lower along the spiral-shaped groove 25A than in the area between adjacent turns.

Configuring the refrigerating circuit with only one spiral-shaped refrigerating duct is particularly advantageous and makes the production easy. However, further embodiments are also possible, for example with a greater number of refrigerating ducts, or with a matrix of refrigerating channels provided in the thickness of the bottom wall <NUM> and connected to an inlet and an outlet of a refrigerating fluid. The channels may be produced, for example, by additive manufacturing.

In the illustrated embodiment, the refrigerating duct <NUM> forms a further plurality of helical turns, which coil outside the second perimeter wall <NUM>. The helical coils, indicated with reference number 15B, are housed in a helical groove 29A provided in the thickness of the second perimeter wall <NUM>.

In assembled condition, the bottom wall <NUM> and the outer wall <NUM> are approximately parallel to each other and form a gap <NUM> (see in particular <FIG>) for thermally insulating the coil <NUM> and the outer wall <NUM> from each other. More specifically, the gap is defined between a surface 25B of the bottom wall <NUM> facing the outer wall <NUM> and a surface 21A of the outer wall <NUM> facing the inner shell <NUM>.

The thickness, i.e. the height of the gap <NUM>, is extremely small, for example in the order of <NUM>-<NUM>, preferably about <NUM>-<NUM>. Spacing elements <NUM> are provided to keep the distance between the surface 25B and the surface 21A (this distance being the thickness or height of the gap <NUM>). The spacing elements <NUM> are advantageously arranged in radial rows, as shown in particular in <FIG>.

In order to reduce the contact between the outer shell <NUM> and the inner shell <NUM> at the gap <NUM>, the spacing elements are, for instance, dot-shaped, i.e., they are shaped like small (for example cylindrical) bodies that extend orthogonally to the surfaces delimiting the gap <NUM> and have very small cross-section, for example a maximum transverse dimension equal to, or lower than, <NUM>. In case the spacing elements <NUM> are cylindrical, the maximum transverse dimension is given by the base diameter thereof.

Furthermore, in the illustrated embodiment the spacing elements <NUM> are arranged in correspondence of the turns of the groove 25A, as clearly shown in Fig. 6A, for purposes that will be explained below. In case the refrigerating duct <NUM> is directly formed, for example by additive manufacturing, in the thickness of the bottom wall <NUM> of the inner shell <NUM>, the spacing elements <NUM> may be provided again in correspondence of grooves constituting the refrigerating duct.

The spacing elements <NUM> may be made in a single piece with the outer shell <NUM> or the inner shell <NUM>. The spacing elements <NUM> are preferably integral with the inner shell <NUM>. In this way, by producing the inner shell <NUM> for example by molding or by additive manufacturing, it is possible to position the spacing elements <NUM> precisely in correspondence of the areas where the bottom wall <NUM> is less thick, i.e. in correspondence of the grooves 25A.

In the illustrated embodiment, inside the second perimeter wall <NUM> a collar <NUM> is provided, coaxial to the walls <NUM> and <NUM>. The collar <NUM> constitutes a centering member between the inner shell <NUM> and the outer shell <NUM>. The collar <NUM> co-acts with a shank <NUM> integral with the outer shell <NUM>. In assembled condition (<FIG>) the shank <NUM> is inserted inside the collar <NUM>.

With the arrangement described above, thermal insulation is provided between the inner shell <NUM>, which houses the coil <NUM> generating heat, and the application surface 3A. Thermal insulation is provided by the gap <NUM> filled with air, which is an effective thermal insulator. Thanks to the use of small spacing elements <NUM>, the conductive heat transfer from the coil <NUM> to the application surface 3A is significantly reduced. Typically, the overall area of the contact surfaces between the outer shell and the inner shell in correspondence of the gap <NUM> is equal to, or lower than <NUM>%, and preferably equal to, or lower than <NUM>% of that of the cross-section (according to plane VII-VII of <FIG>) of the gap <NUM>.

The heat transfer between the inner shell <NUM> and the outer shell <NUM> is further reduced thanks to the fact that the spacing elements <NUM> are provided in correspondence of the groove 25A, i.e. where the refrigerating fluid circulating in the duct <NUM> flows and therefore, the temperature of the material forming the bottom wall <NUM> is minimal.

Claim 1:
An applicator (<NUM>) for magnetic therapy comprising a housing with an outer wall (<NUM>), which defines an application surface (3A) to be applied to a patient, and in which at least one electrically conductive coil (<NUM>) is housed for generating a magnetic field; wherein:
the housing comprises: an outer shell (<NUM>) forming the outer wall (<NUM>); and an inner shell (<NUM>) forming a seat (<NUM>) for housing the coil (<NUM>), wherein the inner shell (<NUM>) comprises a bottom wall (<NUM>) facing the outer wall (<NUM>) formed by the outer shell (<NUM>);
in the housing, a refrigerating device (<NUM>) is provided, comprising at least one refrigerating duct (<NUM>) adapted to circulate a refrigerating fluid and arranged between the coil (<NUM>) and the application surface (3A); wherein the at least one refrigerating duct (<NUM>) is arranged between the coil (<NUM>) and a surface (25B) of the bottom wall (<NUM>) of the inner shell (<NUM>) facing the outer wall (<NUM>) of the outer shell (<NUM>);
a gap (<NUM>) is formed between the bottom wall (<NUM>) of the inner shell (<NUM>) and the outer wall (<NUM>) of the outer shell (<NUM>) for thermally insulating the coil (<NUM>) and the application surface (3A) from each other; and
spacing elements (<NUM>) are arranged in the thermal insulation gap (<NUM>) between the outer wall (<NUM>) of the outer shell (<NUM>) and the bottom wall (<NUM>) of the inner shell (<NUM>).