Patent Description:
The use of an electric makeup brush is known for example from <CIT> for skin treatment. This known device comprises a housing, a detachable brush head with a brush and a gearing mechanism interposed between an electric motor and encased in the housing and the brush.

While the brush itself may be subject to wear and contamination, the more expensive component parts, like the motor, the power source and/or the gearing mechanism, typically have a longer service life. Although many users have several electrically driven devices for skin treatment, including hair removal devices, these devices usually each comprise a motor, a power source and/or a gearing mechanism driving the devices with a different speeds, amplitudes and the like tailored to the individual requirements of the respective device.

Skin treatment devices are also known from <CIT>, <CIT>, <CIT> and <CIT>.

It is an object of the present invention to provide a skin treatment device suitable to be used for different applications and permitting replacement of the brush.

The invention is directed to a skin treatment device as defined in claim.

In accordance with one aspect of the present disclosure, a skin treatment device is provided, comprising a shaver handle housing, a detachable brush head pivotably supported by the shaver handle housing about a brush head pivot axis and a gearing mechanism. The shaver handle housing comprises, i.e. encases, a drive unit for driving at least one drive pin in a, preferably rotatory or linear, oscillating manner with a first amplitude about an oscillation axis which is at least substantially perpendicular to the brush head pivot axis. The brush head comprises a brush rotatable about a brush axis which is at least substantially perpendicular to the brush head pivot axis. The brush comprises at least one driven element coupled to the at least one drive pin by means of the gearing mechanism. The gearing mechanism translates the rotatory oscillating movement of the drive pin into a rotatory oscillating movement of the driven element of the brush with a second amplitude which is smaller than the first amplitude of the drive pin.

In other words, the skin treatment device mainly comprises the component parts of an electric shaver, wherein the exchangeable cartridge containing one or more cutter units is replaced by the brush head with the gearing mechanism. The gearing mechanism may be integrated into the brush head such that the brush head with the gearing mechanism can be attached to the base components of the electric shaver in a simple manner, for example by means of snap elements. The provision of the gearing mechanism allows translating the movement of the at least one drive pin of the shaver to a different movement of the brush which is adapted to the intended use of the brush for skin treatment.

According to a further independent aspect of the present disclosure, an interface for attaching a brush to a skin treatment device is provided, wherein the skin treatment device comprises a drive unit, a component part driven by the drive unit to perform a rotatory oscillating movement and a hood at least partially encasing said driven component part. The brush may be detachably fastened to said driven component part by at least one lug engaging said driven component part by press fit and additionally by at least one snap element engaging said driven component part by snap fit. The at least one lug and the at least one snap element may extend through openings in the hood when the brush is attached to the skin treatment device.

Before describing advantageous embodiments of the invention related to the <FIG>, different aspects of the invention are described more in detail. These aspects disclose further features, advantages and possibilities of use of the present invention that might be combined in any useful combination.

In electric shavers, especially in electric shavers comprising a foil-type upper cutter und a lower cutter with several blades oscillating relative to the upper cutter, hair removal results may be improved by a relatively large oscillating stroke of the cutter elements relative to each other. For example, in an electric shaver with a foil-type upper cutter und a lower cutter having several blades, a drive pin performs an oscillating movement during use with an amplitude in a range between ± <NUM>° and ± <NUM>°, for example about ± <NUM>,<NUM>°, at a relatively high speed in a range between <NUM>,<NUM> rpm and <NUM>,<NUM> rpm, for example about <NUM>,<NUM> rpm. In contrast to that movement of the brush with the above oscillating movement may be undesired in terms of skin sensation and/or splashing of skin treatment products during application. Thus, the gearing mechanism may translate the rotatory oscillating movement of the drive pin into a rotatory oscillating movement of the driven element of the brush with a second amplitude which is smaller than the first amplitude of the drive pin. For example, the second amplitude is smaller than the first amplitude by a factor x, wherein x is between <NUM> and <NUM>, preferably between <NUM> and <NUM>. With a transmission ratio from <NUM>/<NUM> to <NUM>/<NUM> the amplitude of the brush may be in a range between ± <NUM>° and ± <NUM>°. Such an amplitude of the movement of the brush is for example suitable for driving a brush having bristles with a diameter of <NUM> and the length of <NUM> to <NUM>.

The gearing mechanism of the skin treatment device may be designed such that the brush axis and the oscillation axis are at least substantially parallel to each other. For example, the brush axis and the oscillation axis may be identical with each other. This may result in a compact design of the brush head and its gearing mechanism.

According to an exemplary embodiment of the present disclosure, the gearing mechanism may comprise a frame, a driving lever pivotably engaging the at least one drive pin, a connection lever pivotably engaging the driving lever and a brush lever pivotably engaging the connection lever and further engaging the at least one driven element of the brush. Preferably, the driving lever, the connection lever and the brush lever are pivotably supported on the frame. With such a design of the gearing mechanism the amplitude of the brush lever may be adapted by varying the distances of the respective rotation axes of the levers from the respective engagement points of the levers with each other.

While the above mentioned embodiment comprises a gearing mechanism with three levers, other designs with more than three levers or less than three levers are suitable for translating the amplitude of the at least one drive pin to a smaller amplitude, too. Providing additional levers may further reduce the second amplitude of the driven element of the brush.

The brush head is preferably a component part which can be attached to the housing of the shaver, thereby replacing a cartridge with cutters. Thus, it is desirable that the interface of the shaver with the cartridge is further suitable for cooperation with the brush head. In this respect it may be beneficial if the frame comprises at least one opening with the at least one drive pin of the shaver extending through the opening in the frame for interaction with one or more further components of the gearing mechanism. The frame may comprise a first stud and a second stud which is offset from the first stud, wherein the driving lever and the brush lever are supported on the first stud and wherein the connection lever is supported on the second stud.

The shaver handle housing with the interface for driving one or more cutter units has at least one drive pin, typically two drive pins for reciprocally driving two cutter units in opposite directions. For such an embodiment, the skin treatment device may comprise two drive pins mounted on a bridge oscillating about the oscillation axis wherein drive pins are located with the same distance from the oscillation axis on the bridge. Although it is sufficient that the driving lever engages only one drive pin, it is preferred if the driving lever pivotably engages both drive pins.

The skin treatment device may comprise an interface for detachably constraining of the gearing mechanism and/or the brush head to the shaver handle housing. Such an interface may comprise one or more snap hooks for attaching the gearing mechanism and/or the brush head on the shaver handle housing. As an example, the frame of the gearing mechanism of the brush head may be provided with two rigid snap arms having hook-like end portions, whereas the shaver handle housing is provided with one or more spring elements which are deflected by the snap arms during attachment of the brush head on the shaver handle housing and interlock with the hook-like end portions of the snap arms, thereby constraining the brush head on the shaver handle housing in a detachable manner.

The gearing mechanism may be an integral part of the brush head such that the brush head may be attached to the shaver handle housing and detached from the shaver handle housing as one unit. For example, the gearing mechanism may be received in a brush hood encasing the driving lever, the connection lever, the brush lever and the frame. Thus, the brush head may consist of the brush hood and the gearing mechanism with the driving lever, the connection lever, the brush lever and the frame. The brush itself may or may not be part of the brush head.

Although the brush is typically a reusable component part, it may be required to replace the brush, while the rest of the device is not replaced. For this purpose, the brush is preferably detachably fastened to the gearing mechanism. In more detail, the brush may comprise at least one snap element for attaching the brush to the brush lever, wherein the brush hood comprises at least one opening permitting engagement of the driven element and/or the at least one snap element of the brush and the brush lever of the gearing mechanism through the opening.

The driven element of the brush may comprise at least one lug engaging a component part of the gearing mechanism, e.g. the brush lever, by press fit, wherein the brush is additionally attached to said component part of the gearing mechanism by snap fit. For example, the brush comprises two snap elements for attaching the brush to the brush lever by snap fit and four lugs for engaging the brush lever by press fit, wherein the snap elements and the lugs are disposed about the brush axis.

The above mentioned connection structure between the brush and brush holder, i.e. the brush head, is designed to transfer movements around an axis without only relying on the friction between brush and brush holder which would occur with pure press fit connections. Thus, driving transmission functions on the one hand and detachment/attachment functions on the other hand may be separated in the proposed design. This contributes to the manufacturability compared with solutions, where a multi-function is integrated to one feature. The connection between brush and brush holder minimizes the relative movements and maximizes the transmission efficiency due to a direct contact using the press fit in the oscillation direction without losing the transmission between driving unit and brush. At the same time the, e.g. hook-shaped, snap elements are a separate feature constraining the brush to the brush head, thereby preventing that the press fit engagement loses contact during operation.

In addition, the gearing mechanism with its levers is designed to transfer movements around a center shaft, i.e. the brush axis and the oscillation axis, from the driving unit of the shaver handle housing to the brush. The simplified gear chain is designed to adapt the brush attachment for 3D movement, i.e. a movement of the brush head relative to the shaver handle housing about swiveling and/or tilting axes. The directly driving connection between the brush and the brush holder requires only limited space due to the flat levers and the integrated shaft on the frame.

Turning now to the exemplary embodiment depicted in the Figures, a skin treatment device <NUM> is depicted in <FIG>, wherein <FIG> shows the skin treatment device <NUM> with a brush head <NUM> attached to a shaver handle housing <NUM>, whereas the brush head <NUM> is a detached from the shaver handle housing <NUM> in <FIG>.

The shaver handle housing <NUM> is an outer shell in the form of a handle encasing not shown component parts, like an energy source, e.g. a rechargeable battery, a motor, a drive train, a control unit and the like. Such internal component parts may be connected to external component parts of the shaver handle housing <NUM>, for example a switch <NUM> or drive pins <NUM> protruding from support <NUM> of the shaver handle housing <NUM>. Although not depicted in detail in <FIG>, the support <NUM> may be mounted on the shaver handle housing <NUM> permitting a swiveling movement of the support <NUM> with respect to the lower portion of the shaver handle housing <NUM>, for example swiveling to the left and to the right in <FIG>, and/or permitting a tilting movement of the support <NUM> with respect to the lower portion of the shaver handle housing <NUM>, for example tilting back and forth about brush head pivot axis I in <FIG>.

In the embodiment depicted in <FIG>, the drive pins <NUM> are located on a bridge <NUM> with each drive pin <NUM> having the identical distance to an oscillation axis II defined by a shaft of the drive train (see <FIG>).

The support <NUM> of the shaver handle housing <NUM> is designed to receive in a detachable manner a cartridge with one or more haircutting units, for example with a foil-type upper cutter and a lower cutter comprising several blades which are driven by the drive pins <NUM>. The support <NUM> may comprise an interface permitting attachment of such a cartridge, wherein the interface comprises for example a spring element <NUM> designed to interact with hooks (not shown) of such a cartridge (see <FIG>, <FIG>, <FIG>). After removal of the cartridge brush head <NUM> may be attached to the support <NUM> in the same manner.

A brush <NUM> is detachably mounted on the brush head <NUM>. In the depicted embodiment, the brush <NUM> has a substantially circular configuration with several bundles of bristles facing away from the side of the shaver handle housing <NUM>.

The component parts of the brush head <NUM> are depicted in <FIG>. In this embodiment, the brush head <NUM> comprises a frame <NUM>, a hood <NUM>, a driving lever <NUM>, a connection lever <NUM> and a brush lever <NUM>, wherein the frame <NUM> and the levers <NUM>, <NUM>, <NUM> form a gearing mechanism. <FIG>, <FIG> and <FIG> depicted in more detail the arrangement of the component parts of the brush head <NUM>. The frame <NUM> and the hood <NUM> are connected with each other to form a rigid unit permitting attachment and detachment with respect to the shaver handle housing <NUM>. The frame <NUM> is provided with a first stud <NUM> and a second stud <NUM> which are parallel to each other and offset from each other. The first stud <NUM> defines a brush axis III which is identical with the oscillation axis II (see <FIG>). The frame <NUM> further comprises two openings <NUM> through which the drive pins <NUM> extend when the brush head <NUM> is mounted on the shaver handle housing <NUM>. Further, two hooks <NUM> protrude from the frame <NUM> in a direction opposite to the extension of the studs <NUM>, <NUM>, i.e. the lower side in <FIG>. As shown in <FIG>, the frame <NUM> may interact with the spring element <NUM> of the support <NUM> for retaining of the shaver head <NUM> on the shaver handle housing <NUM>.

The driving lever <NUM> has a central opening receiving the first stud <NUM>. Further, the driving lever <NUM> has two arms each having an opening for receiving a respective drive pin <NUM> as shown for example in <FIG> and <FIG>. In other words, when the motor in the shaver handle housing <NUM> is activated, bridge <NUM> performs a rotatory oscillating movement together with the drive pins <NUM> which is transmitted to driving lever <NUM> oscillating about oscillation axis II and brush axis III. The driving lever <NUM> further comprises a pin <NUM> which is offset from the first stud <NUM> but closer to the first stud <NUM> compared with the openings receiving the drive pins <NUM>.

The connection lever <NUM> comprises an opening receiving the second stud <NUM>. Further, connection lever <NUM> has an arm extending away from the second stud <NUM> which has a recess pivotably receiving pin <NUM> of the driving lever <NUM> and which has a further pin <NUM> facing away from the frame <NUM>, i.e. the upper side in <FIG>. The pin <NUM> is located closer to the second stud <NUM> compared with the recess receiving pin <NUM>.

The brush lever <NUM> comprises a central opening receiving the first stud <NUM>. Further, brush lever <NUM> comprises an arm with a recess pivotably receiving pin <NUM> of the connection lever <NUM>. In addition, brush lever <NUM> comprises two first openings <NUM> having an undercut and four second openings <NUM> (see <FIG>).

Due to the arrangement of the levers <NUM>, <NUM>, <NUM> and the pins <NUM>, <NUM> and the respective recesses for receiving the drive pins <NUM> and the pins <NUM>, <NUM>, the rotatory oscillating movement of the bridge <NUM> and the drive pins <NUM> is translated to a rotatory oscillating movement of the brush lever <NUM> with the same speed but with a smaller amplitude. In the example depicted in the Figures, the transmission ratio for the amplitude is between <NUM>/<NUM> to <NUM>/<NUM>, resulting in an amplitude in a range between ±<NUM>° and ± <NUM>° of the brush lever <NUM>.

As can be taken for example from <FIG>, <FIG> or <FIG>, the frame <NUM> and the levers <NUM>, <NUM>, <NUM> are relatively flat and the levers are partially arranged next to each other resulting in a brush head <NUM> which is relatively small in the direction of the oscillating axis II, i.e. in height. Due to the direct contact of the levers <NUM>, <NUM>, <NUM> with each other and with the drive pins, respectively, torque exerted by the drive pins <NUM> is directly transmitted to the brush lever <NUM>.

As can be taken from <FIG> the hood <NUM> of the brush head <NUM> has the central opening and four additional openings mating and aligned with the openings <NUM> and <NUM> of the brush lever <NUM>. With the exception of these openings, the hood <NUM> is substantially closed thereby preventing that dirt or the like enters the gearing mechanism.

The brush <NUM> comprises two snap elements <NUM> and four lugs <NUM> on the opposite side of the brush <NUM> having the bristles, i.e. on the lower side in <FIG>. The snap elements <NUM> and the lugs <NUM> are aligned and mating with the openings <NUM> and <NUM> of the brush lever <NUM> and with the respective openings in the hood <NUM>.

As can be seen in <FIG>, <FIG> and <FIG>, the snap elements <NUM> protrude through the central opening in the hood <NUM> and are snapped into the undercuts of the openings <NUM> in the brush lever <NUM>, thereby axially constraining the brush <NUM> on the brush lever <NUM> of the brush head <NUM>. However, due to the arched design of the openings <NUM>, the snap elements <NUM> do not significantly transmit torque from the brush lever <NUM> to the brush <NUM>. In addition, the openings <NUM> are wider than the width of the snap elements <NUM>, thereby allowing lateral displacement of the snap elements <NUM> in the respective openings <NUM>. The respective opening in the hood <NUM> is wider than the width of the snap elements <NUM>, too, thereby allowing rotation of the brush <NUM> with its snap elements <NUM> relative to the hood <NUM>.

On the other hand, as can be seen in <FIG>, <FIG> and <FIG>, the lugs <NUM> protrude through the respective openings in the hood <NUM> and are press fit into the openings <NUM> in the brush lever <NUM>. Again, the respective openings in the hood <NUM> are wider than the width of the lugs <NUM>, thereby allowing rotation of the brush <NUM> with its lugs <NUM> relative to the hood <NUM>. Thus, while the lugs <NUM> do not significantly retain the rush <NUM> on the brush lever <NUM> in the axial direction, torque is transmitted from the brush lever <NUM> to the brush <NUM> by means of the press fit between the lugs <NUM> and the openings <NUM>.

In other words, the function of axially constraining the brush <NUM> on the brush head <NUM> and the function of transmitting torque to the brush <NUM> are achieved by different features, namely the interaction of snap elements <NUM> with openings <NUM> and interaction of lugs <NUM> with openings <NUM>.

In the depicted embodiment the lugs <NUM> are arranged substantially concentrically with respect to the brush axis III. However, other configurations are suitable for transmitting torque to the brush <NUM>, too. Further, while the provision of several lugs <NUM> may be beneficial in reducing play between the brush lever <NUM> and the brush <NUM> by slightly prestressing the lugs <NUM> and the openings <NUM>, it may be sufficient to provide only one lug <NUM> for transmitting torque from the brush lever <NUM> to the brush <NUM>. Further, the outer shape of the lugs <NUM> is not limited to the depicted substantially rectangular shape. As an alternative, the lugs <NUM> may be cylindrical.

In the exemplary embodiment depicted in the Figures, the hood <NUM> is provided with a substantially cylindrical plateau, while the side facing away from the bristles of the brush <NUM> is provided with a cylindrical skirt receiving this plateau when the brush <NUM> is attached to the brush head <NUM>. This design further contributes in preventing that dirt or the like enters the gearing mechanism and/or the interface between the brush head <NUM> and the shaver handle housing <NUM>.

Claim 1:
A skin treatment device, comprising a shaver handle housing (<NUM>), a detachable brush head (<NUM>) pivotably supported by the shaver handle housing (<NUM>) about at least one brush head pivot axis (I) and a gearing mechanism (<NUM>, <NUM>, <NUM>, <NUM>), wherein the shaver handle housing (<NUM>) comprises a drive unit for driving at least one drive pin (<NUM>) in a, preferably rotatory, oscillating manner with a first amplitude about an oscillation axis (II) which is at least substantially perpendicular to the at least one brush head pivot axis (I), wherein the brush head (<NUM>) comprises a brush (<NUM>) rotatable about a brush axis (III) which is at least substantially perpendicular to the at least one brush head pivot axis (I), and wherein the brush (<NUM>) comprises at least one driven element (<NUM>) coupled to the at least one drive pin (<NUM>) by means of the gearing mechanism (<NUM>, <NUM>, <NUM>, <NUM>), wherein the gearing mechanism (<NUM>, <NUM>, <NUM>, <NUM>) is configured to translate the movement of the drive pin (<NUM>) into a rotatory oscillating movement of the driven element (<NUM>) with a second amplitude which is smaller than the first amplitude of the drive pin (<NUM>).