Abstract:
An applicator is disclosed that is particularly advantageous for cosmetics such as mascara. The applicator includes a twisted core having: a first portion in which are trapped bristles arranged in a radial manner relative to the core, and a second portion fixed in a rod, with the second portion of the core being formed by at least two twisted zones having a different direction and/or pitch. A container or packaging arrangement including such an applicator is also disclosed.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This document claims priority to French Application No. 03 10293, filed Aug. 29, 2003 and U.S. Provisional Application No. 60/501,822, filed Sep. 11, 2003, the entire contents of which are hereby incorporated by reference. 

   FIELD OF THE INVENTION 
   The invention relates to an applicator for a cosmetic product. The invention is particularly advantageous as an applicator for eye make-up such as mascara, to apply the mascara to eyelashes and eyebrows. 
   BACKGROUND OF THE INVENTION 
   Discussion of Background 
   In the field of mascara, the most commonly used applicators are formed from so-called “twisted” brushes. Such twisted brushes are made by placing a layer of bristles between two branches of a steel wire configured in the shape of a hairpin, then twisting the two branches of the steel wire about its axis. The steel wire thus twisted forms a spiral (actually, one spiral or helix for each strand of steel wire) in which the turns rise from left to right in relation to the direction of twist of the steel wire (when the brush is viewed in a vertical position) or from right to left. The first type of twisting produces a brush sometimes referred to as a “left-handed brush”. Such a brush is described in patent EP 0 611 170. The second type of twisting, hitherto the most frequently encountered, produces a brush referred to as a “right-handed brush”. 
   Such twisted brushes generally include a “bristled” part defining an applicator portion, extending into a “non-bristled” part of the steel wire, sometimes referred to as the “tail” of the brush. The non-bristled part serves to fix the device to a rod attached to an element used to grasp the device, with the element also providing a closure cap for the bottle containing the mascara. 
   The brush should be attached to the rod so that the brush does not axially fall out of the rod and is not thereby rendered unusable. The brush attachment should also have considerable rotational restraint so that the brush turns with the rod when the rod is rotated by the user to unscrew the cap from the bottle. The attachment must be especially firm when the mascaras used are mascaras that dry very quickly, i.e. mascaras having a relatively thick formulation and which therefore adhere strongly to the brush and to the bottle. 
   To attach the brush to the rod, the tail end of the brush is generally inserted into a hole fashioned in the rod, with the diameters of this hole and the tail of the brush being substantially equal. The attachment is secured by heating the metal tail of the brush and forcing it into the hole in the rod so that the plastic material of the rod melts locally in contact with the tail of the brush and conforms to the shape of the twist in the tail of the brush. 
   The brush is therefore securely restrained in that the rod, by conforming to the shape of the twist, forms a kind of female thread around the tail of the brush which constitutes a male thread. Thus, any axial movement becomes impossible without deforming the material of the rod or the brush. However, rotation in the direction tending to unscrew the tail from the brush remains easy in that there is no chemical adhesion between the plastic and the metal, and in that this movement involves no mechanical deformation. Thus, the rotational restraint remains low. The unscrewing movement of the brush relative to the rod can occur in the direction of opening or closing of the mascara. 
   To address this problem, a conventional approach is to locally crush the tail of the brush so as to render it locally flat and thus prevent the tail of the brush from unscrewing during the rotational movement. However, this flattening is only effective at fairly low rotational torque values, and is not sufficiently effective for mascaras of relatively thick consistency. 
   SUMMARY OF THE INVENTION 
   One of the objects of the invention is therefore to provide a cosmetic applicator that does not present the drawbacks of the prior art. 
   According to one object of the invention, an applicator is provided in which the brush has minimal or no risk of separating from the rod to which it is attached, even with products of relatively sticky consistency. 
   A further object of the invention is to provide an applicator which can be made in a simple manner and at a low cost. 
   According to the invention, these objects can be achieved, wholly or partially, by a cosmetic applicator, e.g., for mascara, with a twisted core which includes a first portion in which are trapped bristles arranged in a radial manner relative to the core, and a second portion fixed in a rod, with the second portion of the core being formed by at least two twisted zones of different direction and/or pitch. Various alternative features are possible in accordance with the invention. 
   By way of example, the twisted zone of the second portion of the core contiguous with the bristled portion can be twisted in the same direction as the bristled portion. Also, by way of example, the twisted zone of the second portion of the core contiguous with the bristled portion can be twisted with the same pitch as the bristled portion. 
   Further by way of example, the second portion of the core can be formed by a twisted zone with a first pitch and by a twisted zone with a second pitch different from the first. 
   Alternatively, the second portion of the core can be formed by a twisted zone having a progressively increasing, or decreasing, pitch between a first end of the second portion contiguous with the bristled portion of the core and a second end opposite the first. 
   By way of example, the core can be formed from two branches of a steel wire. 
   The bristled portion of the core can present a plurality of turns rising from left to right when the applicator is viewed in the vertical position. In this case, the brush is described as “left-handed”. Alternatively, the bristled portion of the core can present a plurality of turns rising from right to left when the applicator is viewed face on in the vertical position. In this case, the brush is described as “right-handed”. 
   Also, by way of example, the bristled portion of the core can be straight or rectilinear, or alternatively, curved. The rod can be integral with a grasping element. In addition, the bristles can form a brush of circular or polygonal transverse cross-section, for example, triangular, square or pentagonal. 
   One or more of the objects of the invention can also be achieved by a device for packaging and applying a product to keratinic fibers, such as the eyelashes or the eyebrows. The device includes a container holding the product, with the container delineating an opening in proximity to which is preferably disposed a wiper element, with the device equipped with an applicator as described above and described further herein. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will become further apparent from the following detailed description, particularly when considered in conjunction with the drawings in which: 
       FIG. 1  illustrates a partial sectional view of a first embodiment of an applicator according to the invention; 
       FIG. 2  illustrates a partial sectional view of a second embodiment of an applicator according to the invention; 
       FIG. 3  illustrates a partial sectional view of a third embodiment of an applicator according to the invention; 
       FIGS. 4 and 5  illustrate variants of the applicator depicted in  FIG. 1 ; and 
       FIG. 6  illustrates a packaging and application device using an applicator according to the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The applicator device  10  illustrated by way of example in  FIG. 1  is designed to apply mascara. The device  10  includes a rod  30  carrying a brush  40 . In the illustrated example, the rod extends along an axis X. The brush has a circular cross-section, for example, extending transverse relative to the axis X. 
   The brush  40  includes a substantially straight twisted core  20 . The twisted core is obtained, for example, from a steel wire folded into a U shape, between the branches of which a sheet of bristles  41  is inserted before completing the twist operation. In response to the twisting movement, the bristles  41  are drawn in a spiral configuration to form a succession of turns spaced more or less widely apart. The bristles  41  in the illustrated example extend radially in relation to the support and are substantially rectilinear. 
   The sheet of bristles  41  forming the brush is trapped in a first portion  21  of the core  20 . A second portion of the core  22 , without bristles and also referred to herein as the tail of the brush, is fixed in the rod  30 . The end of the rod  20  opposite the brush  40  is generally connected to an element (shown in  FIG. 6 ) that preferably forms both a grasping element for the brush  40  and a closure element for the container with which the brush is associated. 
   In this embodiment, the brush  40  is of the “right-hand brush” type, with the turns of the bristled portion  21  of the twisted core  20  rising from right to left when the brush  40  is viewed in the vertical position as shown. 
   The tail of the brush  22 , which is fixed into the rod  30 , includes two zones  22   a  and  22   b  twisted in two different directions. A first twisted zone  22   a , formed in the extension of the bristled portion  21  of the core  20 , has the same direction of twist and the same pitch as the bristled portion  21  of the core. A second twisted zone  22   b , extending beyond the first twisted zone  22   a , is in this instance twisted in the reverse direction relative to the first twisted zone  22   a  of the tail of the brush. 
   The tail of the brush can have a length, by way of example, of approximately 2 cm. The two twisted zones at the tail end of the brush and the twisted portion carrying the bristles have a pitch, for example, of approximately 1 mm. 
   To make this applicator, after inserting the sheet of bristles between the branches of the steel wire folded into a U-shape, the branches of the steel wire are wound in a first direction so as to form the bristled portion  21  of the core  10  and the first twisted zone  22   a  of the tail  22  of the brush. The two wires are then held at approximately 1 cm from the tip of the tail of the brush, and they are wound in the reverse direction so as to produce the second twisted zone  22   b  at the tail end of the brush. 
   The tail thus obtained is then partially heated and inserted into a hole  31  pre-formed in the rod  30 . The plastic material of the rod melts slightly in contact with the tail and takes on the shape of the tail of the brush. 
   Thus, once the tail end of the brush, i.e. the zones twisted in both directions, has been inserted while hot into the hole in the rod, relative rotational movement of the brush in relation to the rod becomes impossible without severe deformation of the rod, because screwing in one part of the tail imparts an unscrewing action to the other part of the tail of the brush. The brush is thus very securely restrained from rotation relative to the rod. The presence of the twisted zone in the rod also provides effective axial restraint. 
     FIG. 2  illustrates a second embodiment of the applicator  10  according to the invention. In this embodiment, the length of the tail  22  of the brush is twisted in the same direction. However, the tail of the brush includes a first twisted zone  22   a  having a first pitch, for example the same pitch as the bristled portion of the core, and a second twisted zone  22   b  having a different pitch, with this pitch also being constant. The first twisted zone  22   a  of the tail of the brush has a pitch approximately equal to 1 mm, for example, and the second twisted zone  22   b  has a pitch of 1.5 mm, for example. 
     FIG. 3  illustrates a third embodiment of the applicator  10  according to the invention. In this embodiment, the length of the tail  22  of the brush is also twisted in the same direction. However, the tail  22  of the brush includes a first twisted zone  22   a  having a first pitch, for example the same pitch as the bristled portion of the core. The second twisted zone  22   b  of the tail in this instance has a pitch different from that of the first twisted zone but it is not constant over the full length of this zone. The pitch in this second twisted zone increases progressively from the first twisted zone up to the end of the core. Alternatively, the second twisted zone could decrease progressively from the first twisted zone to the end of the core. As a further alternative, the second portion of the core could include a portion in which the pitch increases and/or decreases progressively, so that the increasing or decreasing pitch provides the two zones with different pitches. 
   In the latter two embodiments, relative rotational movement of the brush in relation to the rod without severe deformation of the rod is also prevented, because the pitch of the twisted zone at the tail end of the brush is not constant, to thereby prevent unscrewing. Furthermore, the presence of the twisted zone in the rod also provides effective axial restraint. Here again, the brush is held very securely in the rod. 
     FIG. 4  illustrates an alternative embodiment of the applicator depicted in  FIG. 1 . In this variant, the brush  40  is distinguished from the brush in  FIG. 1  in that it is of the “left-hand brush” type, with the turns of the bristled portion  21  of the twisted core rising from left to right when the brush is viewed in the vertical position. With regard to the advantages afforded by a left-hand twisted core, reference may be made to U.S. Pat. No. 6,227,735, the contents of which are incorporated herein by reference. 
   The brush according to the variant in  FIG. 5  is distinguished from the brush in  FIG. 1  in that the bristled portion  21  of the twisted core  20  is curved, with the curvature corresponding substantially to the curvature of the line of the eyelashes on the eyelid. The tail of the core is preferably still straight. 
     FIG. 6  illustrates a packaging and application device  100  equipped with an applicator device  10  of the type described previously with reference to  FIGS. 1 to 5 . The device  100  includes a container  50  holding a reserve of a cosmetic product, preferably an eye make-up such as mascara, and an applicator  10 . The applicator  10  includes an applicator device of the twisted brush type, preferably attached to the end of a rod  30  extending along axis X. The other end of the rod  30  is integral with a grasping element  60  which also forms a closure cap for the container  50 . The container  50  incorporates a wiper element  70  formed, in this instance by way of example, by a cylindrical sleeve of which one end terminates at a flexible annular lip  71 . When the applicator  10  is in the mounted position on the container  50 , the entire applicator device  10  is preferably located between the wiper lip  71  and the bottom of container. Other types of wiper elements can be used, for example a block of open-cell or semi-open cell foam, traversed axially by a slot or a passage of which the delimiting edges are substantially contiguous when no force is being exerted thereon. 
   To use the applicator, the user unscrews the cap formed by the grasping element  60  and withdraws the applicator  10  from the container  60 . In so doing, the applicator device  10  is caused to pass through the wiper element  70 , thereby regulating the quantity of product distributed on the bristles. The withdrawal movement of the applicator is substantially lengthwise relative to the axis X. After use, the user replaces the applicator in the container, again causing the applicator device  10  to pass through the wiper element  70 . 
   In the foregoing detailed description reference is made to preferred embodiments of the invention. It is evident that variants thereto can be proposed without departing from the invention as claimed herebelow. For example, the transverse cross-section of the brush perpendicular to the axis X can be of any shape other than circular, such as polygonal, or for example square, rectangular, triangular, pentagonal, etc. Similarly, the transverse cross-section of the bristles can be of different shapes, and the brush can include bristles having a single type of cross-section, or bristles having a combination of different cross-sections. 
   Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.