Abstract:
A system for holding a stick in a casing includes an inner cup provided with a plurality of at least partially flexible claws that can assume two positions:—an open position, in which the claws allow the stick to be inserted into the inner cup;—a blocked position in which the claws can penetrate into the stick previously inserted into the inner cup in order to block it; the system further including an outer cup of which the dimensions are designed to allow the claws to shift from the open position to the closed position, and elements for locking the inner cup in the outer cup when the claws are in the blocked position.

Description:
The invention relates to the field of casings for cosmetic products that come in the form of a stick, such as lipstick. 
     More specifically, the invention relates to a system for retaining the stick of material in the casing. 
     SUMMARY OF THE INVENTION 
     A stick of lipstick is generally placed on a support slidably mounted in a casing, and an actuation mechanism allows controlling the sliding. In general, the actuation mechanism consists of a pivoting part, accessible on a lower portion of the casing, in helical connection with the support, such that rotation of the pivoting part, actuated by the user, causes the support to slide in an axial direction within the casing. The stick can thus be extended outside the casing for application, or be retracted into the casing in order to protect and store it. 
     The stick is preferably attached to the support, to prevent it from unintentionally escaping from the support and casing. It is known to retain the stick on its support, for example by impaling. For this purpose, the support is provided with two pointed tabs extending axially which impale the material of the stick when it is inserted on the support. 
     However, such a solution is not satisfactory. Depending on the formulation and on the temperature, the hardness of the stick may be insufficient for such retention by impaling to always be effective. In particular, the current trend is toward soft formulations, for which impalement does not properly hold the stick. 
     In document EP 1098577, it is proposed to combine retention by impalement with resilient arms on the support, these arms not extending parallel to the axial direction. 
     The stick is cooled beforehand to harden it and is then inserted into a housing formed by the support, comprising a bottom and a side surface. Pointed tabs for the impalement project from the bottom of the housing, while the resilient arms are placed on the side wall. The arms are pushed out of the housing when the cooled and hardened stick is inserted into the housing. Then as the stick warms and softens, the resilient arms return to their initial position and penetrate the stick, retaining it axially. 
     However, such a solution involves subjecting the stick to temperature variations, which can be detrimental to the quality of the cosmetic product. 
     It has therefore been proposed to implement claws on the support which are forced into the stick when the support is inserted into the case of the cosmetic packaging, preventing all axial movement. 
     Document U.S. Pat. No. 5,871,295 proposes implementing a plate-shaped support, provided on its edge with projecting arms between which the stick can be installed. The support is then pushed into a housing whose inner wall forms a cam for the arms. The arms slide along the wall and are deformed to penetrate the stick. 
     However, the thrust force exerted on the support is passed on to the stick by the arms. During insertion of the support into the housing, the stick may then be pushed in an axial direction which can cause it to extend out of the support, where the arms cannot penetrate the stick and the locking is absent. 
     Document EP 0 995 367 discloses a cup forming a support for a stick of lipstick. The cup is provided with claws on the edge of the opening through which the stick is inserted into the cup. When the cup is inserted into the casing, the claws fold into the stick. 
     This embodiment allows exerting force, via the claws, in the axial direction which tends to retain the stick against the bottom of the support, in the housing. However, it has the disadvantage of not locking the stick when the support is at the end of the casing, meaning when the user has extended the stick as far as possible from the casing. Indeed, as the claws are flexible, if they are extended out of the casing, they could return to their original position out of the stick, which is then free to detach from the support. 
     SUMMARY OF THE INVENTION 
     For casings of cosmetic products in stick form, the invention aims to propose a solution to these problems of the state of the art. 
     More particularly, the invention provides a support forming a retaining system for effectively locking a stick material, such as a stick of lipstick, on the support. 
     In a first aspect, the invention provides a system for retaining a cosmetic product in the form of a stick of material, in particular a stick of lipstick, in a casing, holding the stick in the provided housing in an effective manner, even for soft compositions. 
     In a second aspect, the invention provides a system for retaining in particular a stick of lipstick in a casing, which reduces the risk of releasing the stick. 
     In a third aspect, the invention provides a system for retaining in particular a stick of lipstick in a casing, which is inexpensive. 
     In a fourth aspect, the invention provides a system for retaining in particular a stick of lipstick in a casing, which is adaptable to existing casings available on the market and which can replace retaining systems already in place in a casing. 
     A description of the invention as characterized in the claims is provided below. 
     According to a first aspect, the invention relates to a system for retaining a cosmetic product in the form of a stick of material, in particular a stick of lipstick, in a casing, the system comprising an inner cup forming a housing for the stick, the inner cup comprising an opening through which the stick can be inserted, the edge of the opening being provided with a plurality of at least partially flexible claws, arranged in a crown extending between a proximal boundary edge, of dimensions greater than or equal to the dimensions of the edge of the opening, and a distal boundary edge. 
     The claws can then take two positions:
         an open position, in which the dimensions of the distal boundary edge are greater than or equal to the dimensions of the edge of the opening, the claws allowing insertion of the stick into the inner cup;   a locking position, in which the dimensions of the distal boundary edge are less than the dimensions of the edge of the opening, the claws being able to penetrate into the stick previously inserted into the inner cup in order to lock the stick.       

     The system further comprises an outer cup, adapted to be slidably mounted in the casing, and forming a sleeve for the inner cup, the sleeve dimensions being adapted to allow the crown of claws to shift from the open position to the closed position by insertion of the inner cup into the outer cup. It also comprises elements for locking the inner cup in the outer cup when the claws are in the locking position. 
     Thus, due to the locking between the two cups, the claws cannot shift to the open position when this is not desired. 
     According to a first embodiment, the outer cup may comprise, on the outer surface of a side wall, at least one lug adapted to be in helical connection with the casing, so as to guide the sliding of the outer cup in the casing. 
     According to a second embodiment, the outer cup comprises, on its bottom, a guide rod provided with at least one fin adapted to be in helical connection with the casing. 
     The retaining system can thus be adapted to any type of guidance in the casing. 
     The locking elements may comprise at least one tab projecting from the outer surface of the bottom of the inner cup and at least one hole in the bottom of the outer cup, the tab and hole snap-fitting together to lock the inner cup in the outer cup when the crown of claws is in the locking position. 
     This embodiment of the locking elements is particularly suitable for use with the first embodiment of guidance in the casing. 
     Alternatively, the locking elements may comprise at least one bead projecting from an inner surface of a side wall of the outer cup and at least one recess in an outer surface of a side wall of the inner cup, the bead and recess snap-fitting together to lock the inner cup in the outer cup when the claws are in the locking position. 
     This alternative embodiment of the locking elements is particularly suitable for use with the second embodiment of guidance in the casing. 
     Advantageously, the claws may each have an inner side facing the housing for the stick, the inner side of the claws being provided with teeth, increasing the retaining force exerted on the stick. 
     The claws are preferably identical to one another and are four to ten in number, for example eight, uniformly distributed around the opening of the inner cup. It has been determined that in this configuration, the retaining force on the stick is optimal and is substantially equally distributed across the cross-section of the stick at the height where the claws penetrate the stick in the locking position. 
     According to a second aspect, the invention relates to a casing of a stick of material for a cosmetic product, provided with a retaining system as presented above, the outer cup cooperating in translation with the casing so as to cause the stick to extend from the casing or retract into the casing. 
     According to a third aspect, the invention relates to a method for assembling a stick of material for a cosmetic product in the casing presented above, comprising the following operations:
         insertion of the outer cup into the casing,   insertion of the inner cup into the outer cup, the claws being in the open position,   insertion of the stick into the housing of the inner cup,   application of force on the stick so as to force the crown of claws of the inner cup into the outer cup, the claws coming into the locking position,   engaging the locking elements between the inner cup and outer cup.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The figures in the drawings are now briefly described. 
         FIG. 1  is a perspective view of a so-called “inner” cup of a system for retaining a cosmetic product in the form of a stick of material, in particular a stick of lipstick, in a casing, the cup comprising claws in an open position. 
         FIG. 2  is a side view of the inner cup of  FIG. 1 . 
         FIG. 3  is a top view of the inner cup of  FIGS. 1 and 2 . 
         FIG. 4  is a sectional view along line IV-IV of the inner cup of  FIG. 3 . 
         FIGS. 5 a  to 5 d    each show an alternative embodiment of the claws of the inner cup. 
         FIG. 6  is a perspective view of a so-called “outer” cup of the retaining system. 
         FIG. 7  is a side view of the outer cup of  FIG. 6 . 
         FIG. 8  is a top view of the outer cup of  FIGS. 5 and 6 . 
         FIG. 9  is a sectional view along axis IX-IX of the outer cup of  FIG. 8 . 
         FIG. 10  is a sectional view of the retaining system, representing the inner cup of  FIGS. 1 to 4  and the outer cup of  FIGS. 6 to 9  in a pre-assembled position with the claws in the open position. 
         FIG. 11  is a sectional view of the retaining system similar to that of  FIG. 10 , with the inner cup and outer cup in an assembled position and the claws in a locking position. 
         FIG. 12  is a sectional view of a variant of the retaining system. 
         FIG. 13  is a sectional view of the retaining system of  FIG. 12  in cooperation with a casing. 
         FIGS. 14 to 16  schematically represent a lipstick casing provided with a retaining system according to the previous figures, in three successive steps of a method for assembling a stick of lipstick in the casing. 
     
    
    
     DETAILED DESCRIPTION 
     Below is a detailed account of several embodiments of the invention, accompanied by examples and with reference to the drawings. 
     In  FIGS. 1 to 9  are illustrated the parts of a system  1  for retaining a cosmetic product in the form of a stick  2  of material, in a casing. The cosmetic product is a stick of lipstick, for example. 
     The retaining system  1  comprises a so-called “inner” cup  3  and a so-called “outer” cup  4 . 
     The inner cup  3  comprises a side wall  5 , advantageously, as will be seen below, cylindrical and symmetrical about a longitudinal axis A, closed at one end by a bottom  6  and forming an opening  7  at the other end. The inner cup  3  thereby forms a housing  8  between its side wall  5  and the bottom  6 , for the stick  2  which can be inserted into the housing  8  through the opening  7 . 
     The opening  7  is delimited by an edge  9 , the dimensions of which are adapted to allow insertion of the stick  2  into the housing  8 . The edge  9  of the opening  7  is provided with a plurality of claws  10  arranged in a crown. 
     “Claw” is understood to mean any element or roughness projecting from the edge  9  of the opening  7  towards the exterior of the opening  8 , regardless of the shape, capable of penetrating into the stick  2  when a specific force is applied. 
     The crown of claws  10  extends between a proximal boundary edge and a distal boundary edge, meaning that when the inner cup  3  is viewed in a plane perpendicular to the longitudinal axis A, the claws  10  are between the proximal boundary edge and the distal boundary edge. The dimensions of the proximal boundary edge are greater than or equal to the dimensions of the edge  9  of the opening  7 . 
     More specifically, each claw comprises a proximal end  11  fixed to the edge  9  of the opening and a free distal end  12 . Thus, in practice, as the inner cup  3  forms a right circular cylinder, the proximal boundary edge is a circle passing through the proximal ends  11  of each claw  10  and the distal boundary edge is also a circle passing through the distal ends  12  of each claw  10 , meaning that the proximal boundary edge coincides with the edge  9  of the opening  7  of the inner cup  3 . A slot  13  is formed between each claw  10 . 
     The claws  10  are at least partially flexible, meaning that they comprise at least one flexible portion allowing them to be hinged relative to the edge  9  of the opening  7 . 
     “Flexible” is understood to mean that a claw can be deformed, elastically or plastically, without breaking under the action of a stress exerted manually by an operator. 
     For example, the claws are flexible in at least a portion extending from the proximal end  11 , and can be harder as the distal end  12  is approached. The slots  13  may extend beyond the claws  10 , into the side wall  5  of the inner cup  3 , in particular in order to increase the flexibility of the claws  10 . 
     To facilitate production, the claws  10  are identical to one another. There are, for example, between four and ten, uniformly distributed around the opening  7  of the inner cup  3 . For example, the retaining system  1  comprises eight claws. 
     Thus, due to their flexibility, the crown of claws  10  can take two positions:
         an open position, in which the dimensions of the distal boundary edge are greater than the dimensions of the edge  9  of the opening  7 , the claws  10  allowing insertion of the stick  2  into the inner cup  3  through the opening  7 ;   a locking position, in which the dimensions of the distal boundary edge are less than the dimensions of the edge  9  of the opening  7 , the claws  10  being able to penetrate into the stick  2  previously inserted into the inner cup  3  in order to lock the stick.       

     More precisely, in the example of the figures, in the open position, the proximal boundary edge being coincident with the edge  9  of the opening, in the open position, the claws  10  are completely out of the housing  8 , allowing access for insertion of the stick  2  into the housing  8  of the inner cup  3 . In other words, the claws  10  in the open position flare outward from the housing  8 . Then, in the locking position, the claws comprise at least one portion extending into the housing  8 . When the stick  2  has been previously inserted into the housing  8  of the inner cup  3  with the claws  10  in the open position, the claws brought into locking position bite into the stick  2 , retaining it in the housing  8 . 
     The claws  10  each have an inner side directed towards the housing  8  for the stick  2 . In order to increase the grip of the claws  10  in the stick  2 , the inner surface of the claws  10  may be provided with teeth  14 , each tooth  14  forming a ridge  15  projecting toward the inside of the housing  8 . Each claw  10  may comprise one or more teeth  14 , as represented in particular in  FIGS. 5 a  to 5 d   . The ridges of the teeth  15  are then substantially parallel to one another and extend in a plane perpendicular to the longitudinal axis A. 
     The outer cup  4  then allows deforming the claws  10 , due to their flexibility, and moving the claws  10  from the open position to the locking position. To this end, the outer cup  4  forms a sleeve for the inner cup  3 , meaning that the dimensions of the outer cup  4  allow inserting the inner cup  3 . More specifically, the outer cup  4  also comprises a cylindrical side wall  16  symmetrical about a longitudinal axis B, whose inner diameter is substantially equal to the outer diameter of the side wall  5  of the inner cup  3 . The side wall  16  of the outer cup  4  is closed at one end by a bottom  17  and forms an opening  18  at the other end. 
     By inserting the inner cup  3  into the outer cup  4  such that the longitudinal axis A of the inner cup  3  is coincident with the longitudinal axis B of the outer cup  4 , the claws  10  of the inner cup  3  in their open position abut against the edge  19  of the opening  18  of the outer cup  4 . By applying a force along the longitudinal axis A, the claws are forced to flex towards the inside of the housing  8  in order to shift into the locking position. The slots  13  are dimensioned so that in the locking position, the claws  10  do not overlap. Advantageously, in the locking position, the claws  10  are in contact with their neighbors, forming a closed surface. 
     The retaining system  1  further comprises elements  20  for locking the inner cup  3  in the outer cup  4  when the claws  10  are in the locking position. These locking elements  20  prevent all movement between the inner cup  3  and outer cup  4 , at least along the longitudinal axis A. 
     According to a first embodiment, the locking elements  20  are formed on the bottoms  6 ,  17  of the cups  3 ,  4 . The locking elements  20  comprise at least one tab  21  projecting from the outer surface of the bottom  6  of the inner cup  3  and at least one hole  22  in the bottom  17  of the outer cup  4 . The tab  21  and hole  22  snap-fit together, so that when the inner cup  3  is forcibly inserted into the outer cup  4 , and the claws move to the locking position, the tab  21  is simultaneously inserted into the hole  22  where it snap-fits to lock it in place. According to one embodiment, which is illustrated in particular in  FIGS. 1 to 11 , the hole  22  is substantially circular and central in the bottom  17  of the outer cup  4 . The inner cup  3  comprises two tabs  21 , each forming a portion of the same cylinder. At least one bead  23 ,  24  as represented in  FIGS. 10 and 11 , or two beads as illustrated in  FIGS. 1, 2, and 4 , is formed on each tab  21 , having dimensions adapted to those of the hole  22  in order to achieve the snap-fitting effect. When the tabs  21  are inserted by force into the hole  22 , the beads  23 ,  24  thus force the tabs  21  to flex slightly towards each other. The beads  23 ,  24  enter the hole  22  and then, once they pass beyond it, the tabs  21  return to their initial position. The bottom  17  of the inner cup  4  is then trapped between the beads  23 ,  24  of the tabs  21  and the bottom  6  of the inner cup  3 . 
     According to a second embodiment, illustrated in particular in  FIGS. 12 and 13 , the locking elements  20  are formed on the side walls  5 ,  16  of the cups  3 ,  4 . The locking elements  20  comprise at least one annular bead  25 , two beads  25  in the example of  FIGS. 12 and 13 , projecting from the inner surface of the side wall  16  of the outer cup  4 , and at least one annular recess  26  formed on the outer surface of the side wall  5  of the inner cup  3 . The beads  25  and the recess  26  snap-fit together. Specifically, upon insertion of the outer cup  3  into the inner cup  4 , the beads  25  slide along the outer surface of the side wall  5  of the inner cup  3 , forcing the side wall  5  of the inner cup  3  and/or the side wall  16  of the outer cup  4  to deform slightly. The beads  25  reach the recess  26  substantially at the same moment as the claws have moved to the locking position. The beads  25  thus enter the recess  26 , the side walls  5 ,  16  resuming their initial position. The dimensions of the beads  25  and the recess  26  are such that the inner cup  3  is then locked, at least along the longitudinal axis A, with respect to the outer cup  4 . 
     The retaining system  1  is intended to be mounted in a casing  27 , in particular for lipstick, for which the retaining system  1  also forms a support for the stick  4 . 
     To this end, the outer cup  4  is sized to be mounted so as to be slidable along the longitudinal axis A within the casing  27  and comprises guide elements  28  in the casing  27 . 
     According to a first embodiment, the guide elements  28  are formed on the outer surface of the side wall  16  of the outer cup  4  and comprise at least one lug  29  projecting from the outer surface of the side wall  16  of the outer cup  4 . In practice, the outer cup  4  is provided with two diametrically opposed lugs  29 . The casing  27  then comprises an inner body  30  on which are formed two slots extending along the longitudinal axis A. A shell  31  provided with two helical grooves is fitted onto the inner body  30 . The lugs  29  of the inner cup  4  are each placed in a slot and a helical groove. An outer sleeve  32 , to which the shell  31  is fixed, surrounds the whole. A mechanism  33  for actuating the inner body  30 , accessible for example on a lower portion of the casing  27 , allows rotating the inner body  30  with respect to the shell  31  and thus causes displacement of the outer cup  4 , inner cup  3 , and stick  2 , within the casing  27 , in the direction of the longitudinal axis A, due to the helical connection of the lugs  29  on the casing  27 . 
     This first embodiment of the guide elements  28  is advantageously combined with the first embodiment of the locking elements  20  for locking the inner cup  3  in the outer cup  4 , on the bottoms  6 ,  17 . 
     According to a second embodiment, the guide elements  28  are formed on the bottom  17  of the outer cup  4 . To this end, the outer cup  4  comprises a guide rod  34 , extending from the outer surface of the bottom  17  along the longitudinal axis B of the outer cup  4 . The guide rod  34  has a non-symmetrical cross-section, and is provided at its free end with at least one fin  35  projecting perpendicularly to the longitudinal axis B, in practice two fins  35 , each being adapted to cooperate with a helical groove  36  of a shell  37  of the casing  27 . The guide rod  34  is inserted into a non-symmetrical slot  38  of a guide  39  of the casing  27 , preventing relative rotation between guide rod  34  and guide  39 . The assembly is placed in an outer sleeve  40 . Thus, by actuating the rotation of the shell  37 , via a mechanism accessible to a user (not shown in the figures), the fins  35  slide in the grooves  36 , causing translation of the guide rod  34  and outer cup  4  in the casing  27  along the longitudinal axis A, due to the helical connection of the guide rod  34  on the casing  27 . 
     This second embodiment of the guide elements  28  is advantageously combined with the second embodiment of the locking elements  20  for locking the inner cup  3  in the outer cup  4 , on the side walls  5 ,  16 . 
     The assembly of the stick  2  in the casing  27  can then be carried out as follows. 
     The outer cup  4  is first inserted into the casing  27 , so that the guide elements are installed  28  in the casing  27 . 
     The inner cup  3  is inserted into the outer cup  4 , the claws  10  remaining in the open position. More specifically, the claws  10  are in abutment against the edge  19  of the opening  18  of the outer cup  4 . 
     Next the stick  2  is inserted into the housing  8  formed by the inner cup  3 , until it abuts against the bottom  6  of the inner cup  3 . 
     Force is then applied to the stick  2  along the longitudinal axis A and transmitted to the inner cup  3 . The claws  10  are then forced to move beyond the edge  19  of the outer cup  4  and to flex toward the inside of the housing  8 , where the stick  2  is located. The claws  10  are then in the locking position, and penetrate the stick  2 . The material of the stick  2  is now all around the claws  10  and the slots  13 . The claws are anchored in the stick  2 , which can no longer move, both in translation along the longitudinal axis and in rotation about the same axis. 
     The claws  10 , by biting into the stick  2 , exert a force on the stick  2  along the longitudinal axis A which tends to hold the stick  2  against the bottom of the inner cup  3 . 
     The assembly of the stick is then particularly simple, with a single movement of insertion of the stick  2  into the retaining system  1  and casing  27 . The result is an optimal locking, the material of the stick coming through the slots  13  to surround each claw  10 , preventing any movement between the stick  2  and the retaining system  1 . 
     The association of inner cup  3  and outer cup  4  provides in particular a secure and effective retention of the stick  2  in its support formed by the retaining system  1 . 
     In particular, when the retaining system  1  is extended as far as possible out of the casing  27 , the claws  10  are still firmly anchored in the stick  2  due to the outer cup  4  being locked to the inner cup  3  and continuously exerting force on the claws  10  which retains them in the locking position, decreasing the risk of the stick unintentionally escaping. 
     The retaining system  1  is inexpensive. 
     The inner cup  3  and outer cup  4  are, for example, obtained by molding thermoplastic material. To facilitate the bending of claws  10  in order to shift to the locking position, the outer cup  4  is preferably formed of a material harder than that of the inner cup  3 . 
     The retaining system  1  can be adapted to any type of case. In particular, the guide elements  28  with the casing  27  can be placed on the bottom  17  of the outer cup  3  or on its side wall  16 . Thus, the described retaining system  1  does not require developing new parts for the casing, as existing casings are able to integrate the retaining system  1 .