CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2019/063704 filed May 28, 2019, which claims the benefit of European Patent Application Number 18174994.6 filed May 30, 2018. These applications are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to a body care system for cooling a body part. It finds application in treatments of skin surface of humans and/or animals.

BACKGROUND OF THE INVENTION

In the body care or personal care domain, both for male and female users, there exist various examples of providing a cooling effect on a body part such as skin. For instance, active cooling and passive cooling are used for such purposes. Examples of active cooling include the use of Peltier elements, e.g. in puffy eye treatment devices, or Braun's CoolTech shaver. Examples of passive cooling include rotatable skin brushes and epilators in which a cooling element needs to be cooled (e.g. by placing the cooling element in a freezer) in advance of the treatment session.

A cooling device for body care such as skin care is able to provide both a treatment effect and a specific experience felt by the user. As treatment effect, the cooling may be used to remove or at least temporarily take away eye bags and wrinkles. It may also be used to treat or reduce skin irritations, e.g. those caused by shaving. Another benefit is the numbing of nerves prior to epilation. From the experience point of view, the cool feeling on the skin may give a feeling of calm and relaxation or a kind of pampering to the treated user. This can be the case with or without a combination of the cooling with other measures such as massaging.

Peltier elements are expensive in the context of personal care. Besides, the energy efficiency of Peltier elements is rather limited. Another challenging problem is that in a Peltier element next to a cool surface, also heat is generated. This heat needs to be removed away from the skin contact area as otherwise the user may have a feeling that the skin is being heated up. In order to avoid this, heat sinks or fans are needed, which make the cooling device more bulky and more expensive.

For passive cooling, the cooling element needs to be cooled down in advance to applying the cooling element to the user. This may be time-consuming. This means the user needs to schedule in advance when to place the cooling element in the freezer, or store the cooling element always in the freezer so it is ready for use at any time. This, however. takes up storage space in the freezer. Further, storing a cooling element in the freezer next to foods such as meat balls and left overs may not be found appropriate by the consumers.

US20100331795A1 suggests a hair removal device having a hair removal unit and a skin cooling unit, wherein the skin cooling unit has a skin contact surface, and the skin cooling unit is equipped to apply an application substance onto the skin by way of the skin contact surface during use of the hair removal device.

U.S. Pat. No. 5,849,018 A discloses a mechanical epilator for pulling hairs from the skin, the epilator including an epilator member, e.g., constituted by a roller made up of disks and of blades, that is rotatable about an axis and that is driven by an electric motor, in association with a mechanical coupling member.

US 2006/276731 A1 discloses an appliance or device for massaging and/or dispensing a cosmetic product held in a container mounted on a housing of the appliance.

FR 2 849 588 A1 discloses an automatic foot washing device that is configured to wash one feet at a time or to wash to feet simultaneously.

FR 2 918 545 A1 discloses an assembly for the packaging and application of a cosmetic composition.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a body care system for cooling a body part which enables a less expensive, more energy efficient way of cooling a body part in body care such as skin care. The body care system can be implemented as a standalone device or integrated together with other functions, e.g. those of an epilator.

In a first aspect of the present invention a body care system for cooling a body part is presented that comprises a brush unit including a plurality of airflow generating structures extending radially outwards with respect to a rotational axis of the brush unit, a driving unit configured to drive the brush unit to rotate said brush unit about its rotational axis to generate, by the rotational motion of the airflow generating structures, an airflow in order to evaporate a cooling medium, wherein the rotational axis is configured to be substantially parallel to a surface of the body part during application of the body care system, a connecting unit connecting the brush unit to a driving unit, a supplying unit arranged inside the brush unit for supplying a cooling medium to the plurality of airflow generating structures of the brush unit to evaporate the cooling medium by the generated airflow, and a brush housing at least partially covering an outer surface of the brush unit, such that the surface of the body part to be cooled during application of the body care system and the brush unit covered by the brush housing are physically separated from each other by a part of the brush housing during application of the body care system.

Preferred embodiments of the invention are defined in the dependent claims. It shall be understood that the claimed system has similar and/or identical preferred embodiments as the claimed device and as defined in the dependent claims.

The body care system may be a stand-alone device or integrated into a body care system. The brush unit is drivable by the driving unit (e.g. of a body care system) to carry out rotational motions. For this, the connecting unit is provided to connect the brush and the driving unit. The connecting unit may be arranged as e.g. a joint for accommodating a rotation shaft extending from the driving unit (e.g. a motor). Fixation means (e.g. threads and/or screws) may be provided to rotatably fix the shaft at the brush unit so that the shaft is rotatable about the axis of the brush unit but fixed with respect to the brush regarding the motion in the direction along the shaft.

The plurality of airflow generating structures may comprise, without being limited to, filaments, fibers, flaps, etc. Further, the plurality of airflow generating structures may be of the same in length and/or width. The filaments may comprise the same of different materials such as textile, plastic, rubber and the like. In the following, the present invention is described using the exemplary but non-limiting embodiments where filaments are utilized as airflow generating structures.

The supplying unit is adapted to supply the cooling medium, e.g. water or another cooling liquid, to the filaments. Different types of supplying unit are thinkable for the present invention as long as the cooling medium can reach the filaments of the brush unit. Preferably, the cooling medium may be supplied in between the filaments. The supplying unit may be adapted so as to apply a predefined amount of the cooling medium to one or more of the filaments. The supplying unit may comprise a reservoir containing the cooling medium arranged within the brush unit or in a vicinity of the brush unit.

When the body care system is brought into close proximity of a surface of a body part of a user (e.g. skin surface) and when the device is held so that the rotational axis is aligned to be parallel to the skin surface, the rotational motions carried out by the plurality of filaments of the brush unit is capable of caressing or massaging the skin surface. Similar effects may be achieved when the body care system is held so that the rotational axis is aligned to be oblique to the skin surface, as long as the contact between the brush unit and the skin surface is maintained.

Due to rotational motions of the brush unit, the filaments of the brush unit and thus also the cooling medium supplied to the brush unit from the supplying unit carry out a rotational motion about the rotational axis parallel to the skin surface. This may lead to cooling of the skin surface.

In this context, the expression “substantially parallel” shall be understood such that the inclined angle between the surface of the body part and the rotational axis is less than ±10° when the body care system is used and held as intended. Due to the rotational motion of the brush unit the filaments (i.e., the airflow generating structures) carry out a rotational motion about the rotational axis being substantially parallel to the skin surface. This leads to cooling as the rotation of the filaments (which are in contact with the skin surface) generates an airflow on the skin. If the rotational axis were arranged perpendicular to the skin surface (i.e., if the body care system were used and held incorrectly) the rotation of the brush unit including the filaments would not generate an efficient airflow for cooling the skin surface. The orientation of the rotational axis with reference to the skin surface and the intended use of the body care system by a user will be explained below in more detail with reference to the figures.

In particular, the cooling medium at the filaments of the brush unit experiences an airflow since the cooling medium rotates and thus carries out a relative motion with respect to the surrounding air. This causes evaporation of the cooling medium during which heat is absorbed from the cooling medium. This cools down the filaments locally. Via contact between the filaments and the skin surface, the cold (lower temperature) is transferred to the skin surface.

The cooling may occur by another mechanism: the rotation of the filaments generates an airflow on the skin surface in close proximity to the brush unit. Also, the cooling medium supplied from the supplying unit to the filaments may arrive at the skin surface due to contact between the brush unit and the skin. Thus, the airflow on the skin surface causes evaporation of the cooling medium on the skin surface, thereby cooling down the skin surface locally.

These two mechanisms are not limiting for the present invention. For instance, the airflow caused by the rotation of the filaments in the other mechanism above may cause evaporation of cooling medium that has been brought to the skin surface prior to rotation of the filaments.

The present invention uses a compact design and achieves cooling effectively.

At least a part of the brush housing is arranged between the outer surface of the brush unit and the user when applying the body care system in conjunction with a body care system such as a skin treatment device or epilator. In this way, the skin surface of the user and the brush unit covered by the brush housing are physically separated from each other during application of the body care system. Thus, a direct physical contact between the skin surface and the cooling medium such as water can be avoided. The skin is thus not affected or moistened by the cooling medium from the filaments. Also, a more cost-efficient alternative of indirect body care system to a conventional Peltier element is realized.

In another preferable embodiment, the brush housing comprises a thermal conducting material. In this way, the cooling effect is established fast after switching on the device. A thermal conducting material may include, without being limited to, acrylic glass, fiber glass, metal, metal alloy, plastics, Teflon.

In still a further preferable embodiment, the thermal conducting material comprises a metal. Possible metals include, without being limited to, aluminum, copper, iron, steel and alloys consisting these metals. This enables a cost-efficient body care system.

In still a further preferable embodiment, the thermal conducting material has a thermal conductivity that is within a range from 20 to 400 W/(m·K). This enables fast establishing of the cooling effect after switching on the device. For instance, when the thermal conducting material comprises steel, the thermal conductivity may be approx. 20 W/(m·K). When the thermal conducting material comprises copper, the thermal conductivity may be approx. 385 W/(m·K).

In still a further preferable embodiment, the thermal conducting material has a specific heat capacity that is within a range from 0.35 to 0.95 J/g° C. This prevents cooling down of the brush housing immediately when bringing the body care system into contact with a skin surface (e.g. face of a human). For instance, when the thermal conducting material comprises copper, the specific heat capacity may be approx. 0.38 J/g° C. When the thermal conducting material comprises aluminum, the specific heat capacity may be approx. 0.90 J/g·° C.

In still a further preferable embodiment, the brush housing is formed to receive the brush unit from a body-facing side of the brush unit, the brush housing comprising a body-facing outer surface for covering the bottom surface of the brush unit, wherein the body-facing outer surface of the brush housing and the body-facing side of the brush unit are both facing towards the body part to be cooled during application of the body care system. The brush housing may take a cylindrical, rectangular or another form having a lateral side for (e.g. guidedly) receiving the brush unit and a bottom side for covering the bottom surface of the brush unit. This enables a compact design which is cost-efficient. The bottom side of the brush housing may comprise a flat or a slightly curved outer surface towards the skin surface during use of the body care system. This enables sufficient contact to the skin surface during use of the body care system so that the cooling is more efficient. Further, a flexible surface with proper thermal and mechanical properties is advantageous since such a surface may adapt to the curvature and/or contour of the skin surface. Such a flexible surface may be formed using e.g. aluminum or copper, preferably thin aluminum or copper foils. As an alternative to flexible it is also possible that the housing is fixed to the handle in a suspended way. Due to the suspension the housing can follow the curvature and/or contour of the skin surface independent from the movement of the handle and thus hand motion of the user.

In still a further preferable embodiment, the brush housing comprises at least one air venting opening. In this way, the evaporation process of the cooling medium from the filaments is enhanced during rotation of the brush unit. This increases the direct thermal exchange between the cooling medium from the filaments and the brush housing. Also, this improves the cooling effect during use on a skin. The air venting opening may be arranged on different sides of the brush housing such as, without being limited to, a lateral side or a top side. The number of venting openings may be preferably more than one so that air circulation is improved.

In still a further preferable embodiment, the at least one air venting opening comprises a lateral air venting opening. This enables effective cooling as well as easy production of the body care system.

In still a further preferable embodiment, the body care system further comprises a thermal connector attached to the body-facing side of the brush housing. This allows integration of the body care system together with another product function such as epilation or shaving. For instance, in case of an epilator, the thermal connector may comprise an inner cavity for accommodating the epilator rings. In this way, a cooling experience is possible and the impact on visibility on the other product function is limited. The thermal connector may have a thermal conductivity within the range from 20 to 400 W/(m·K).

In still a further preferable embodiment, the body care system further comprises a contact element for contacting a body part of a user. The contact element is attached to or belongs to the thermal connector. Preferably, the contact element is arranged at a bottom surface (i.e., a body-facing surface) of the thermal connector and may have a flat or curved form. The cooling effect is thus efficiently achieved. Further, a contact element having a flexible surface with proper thermal and mechanical properties is advantageous since such a surface may adapt to the curvature and/or contour of the skin surface. Such a flexible surface may be formed using e.g. aluminum or copper, preferably thin aluminum or copper foils. As an alternative to flexible it is also possible that the housing is fixed to the handle in a suspended way. Due to the suspension the housing can follow the curvature and/contour of the skin surface independent from the movement of the handle and thus hand motion of the user.

In still a further preferable embodiment, the supplying unit comprises a reservoir containing the cooling medium. This enables an integrated product which does not need an external container for storing the cooling medium.

In still a further preferable embodiment, the reservoir is arranged within the brush unit. This enables a short distance over which the cooling medium needs to be transferred until it reaches the filaments, thereby increasing the cooling efficiency since the part of the cooling medium in the vicinity of the filaments is higher. Also, the entire cooling medium is within the brush unit that is being cooled during rotation of the brush unit, so that loss of cold is reduced. The reservoir has preferably a plurality of openings for transferring the cooling medium to the filaments. The reservoir may have a circular cross-section so that the transfer of cooling medium is more homogeneous in different spatial directions.

Alternatively, another reservoir is arranged within a housing of a body care system comprising the driving unit. In this way, the size of the reservoir is not limited to the brush unit. Preferably, a liquid connection is provided between the reservoir and the brush unit for transferring the cooling liquid to the filaments.

