Patent Document

FIELD OF THE INVENTION 
       [0001]    The invention concerns the field of methods and machines for attaching a stick of lipstick to a lipstick dispenser. 
       PRIOR ART 
       [0002]    A stick of lipstick conventionally consists of a paste of cosmetic product which the user can apply by pressing it against her lips. The end of the stick which is placed against the lips is generally contoured for lips. The opposite end of the stick is often nested inside a receptacle of the dispenser. The receptacle is sometimes called a “cup,” the stick of lipstick is called a “bullet,” and the process of attaching the bullet inside the cup is called “nesting” the bullet. 
         [0003]    In the case of a stick of lipstick made of soft paste, nesting it inside the cup requires exerting pressure on the end intended for the user&#39;s lips. The nesting force exerted can deform this end, which is undesirable. 
         [0004]    In the case of a stick of lipstick made of hard paste, the position of the stick of lipstick relative to the dispenser may vary after insertion, which is undesirable. 
         [0005]    Patent DE 900 544 therefore describes injecting a stream of compressed air in order to propel the stick to its nested position. 
       OBJECT AND SUMMARY OF THE INVENTION 
       [0006]    The aim of the invention is to overcome at least one of the above disadvantages. 
         [0007]    A first aspect of the invention concerns a method for attaching a stick of lipstick to a dispenser, the stick comprising a distal end intended for the lips, the dispenser comprising a receptacle having an insertion opening adapted to fit with a proximal end of the stick. The method comprises:
       a moving step in which the insertion opening and the proximal end of the stick are brought adjacent to one another so that the insertion opening is substantially blocked, and   a nesting step in which the stick is nested in the receptacle due to negative pressure created within the receptacle by a vacuum pump.       
 
         [0010]    Because of the negative pressure, the force that must be exerted on the lip-application end of the stick can be reduced or even eliminated. Instead of being pushed, the stick of lipstick is partially or completely drawn in via the negative pressure created in the receptacle. Retention of the stick in the receptacle is established by the adapted insertion opening. It is thus possible to assemble sticks of lipsticks of softer paste than are usable with traditional attachment methods, or to assemble sticks of lipsticks having more fragile contoured ends, or to obtain better positional regularity for sticks of lipsticks of harder paste. 
         [0011]    Advantageously, the receptacle comprises a bottom which the bullet is brought against by the exerted suction. 
         [0012]    Advantageously, the method comprises a molding step in which the stick of lipstick is molded, the nesting step being preceded by a step of unmolding an area at the proximal end of the stick. 
         [0013]    Advantageously, the stick is supplied within a shell having a deformable wall (the shell for example being part of a stick mold), and simultaneously with establishing a negative pressure inside the receptacle, negative pressure is created by a vacuum pump on the shell in order to release the stick from it. 
         [0014]    Advantageously, a receptacle is used which has an internal area communicating with the outside via the insertion opening and via a port, an annular wall of the receptacle extending between the insertion opening and the port. The method comprises:
       a step of confining an area outside the receptacle which includes the port, wherein a chamber is connected in a substantially fluid-tight manner to the annular wall, the insertion opening remaining outside the chamber, and   a step of creating a negative pressure inside the chamber so that this negative pressure is propagated into the internal area via the port.       
 
         [0017]    Advantageously, the annular wall has the same inside profile, adapted to fit to the stick, as the insertion opening, so that the stick is kept aligned with the axis of insertion. 
         [0018]    In one variant, the nesting step includes a step of adjusting the position of the stick of lipstick within the receptacle of the dispenser by creating, within the receptacle, positive pressure or negative pressure relative to the atmospheric pressure. 
         [0019]    Another aspect of the invention relates to a method for assembling a lipstick dispenser, comprising a step of preassembling the receptacle with an actuation mechanism of the dispenser, one of the above methods for attaching the stick of lipstick, and subsequent to the attachment of the stick of lipstick, a step of assembling the actuation mechanism with a decorative shell. 
         [0020]    Advantageously, the decorative shell can be assembled away from the stick of lipstick attachment machine. This reduces the risk that the decorative shell will be scratched. 
         [0021]    In yet another aspect, the invention concerns a machine for attaching stick of lipstick to a dispenser, the stick comprising a distal end intended for the lips, the dispenser comprising a receptacle having an insertion opening adapted to fit with a proximal end of the stick. The machine comprises:
       a moving mechanism for bringing the insertion opening and the proximal end of the stick adjacent to one another so that the insertion opening is substantially blocked, and   a device for creating negative pressure inside the receptacle so that the stick is nested inside the receptacle.       
 
         [0024]    Advantageously, the device for creating a negative pressure in the receptacle comprises a chamber connected to a vacuum pump and a device for establishing a substantially fluid-tight connection of the chamber to the dispenser receptacle. 
         [0025]    In a variant concerning the assembly of dispensers comprising an actuation mechanism, the chamber is able to receive at least part of the actuation mechanism. 
         [0026]    In a variant concerning the assembly of dispensers comprising an actuation mechanism equipped with a body within which the receptacle slides axially between a retracted position and a protruding position, said body being adapted to fit with the receptacle in the protruding position; said machine comprising a device for establishing a substantially fluid-tight connection of the chamber to the body. Thus the substantially fluid-tight connection between the receptacle and the chamber involves the body of the actuation mechanism fitting with the receptacle and includes the substantially fluid-tight connection of the chamber to the body of the mechanism. 
         [0027]    Advantageously, the machine comprises a stick of lipstick molding station having a removable spacer intended for molding the proximal end of the stick and a controllable arm for extracting the removable spacer. 
         [0028]    Advantageously, the molding station comprises a wall of deformable material delimiting a mold cavity, an outside cavity surrounding the deformable wall, and a means for creating a vacuum in the outside cavity. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0029]    The invention will be better understood by referring to the following detailed description of a few embodiments provided as non-limiting examples and illustrated by the accompanying drawings in which: 
           [0030]    FIG  1  is a longitudinal cross-section of a machine for attaching stick of lipstick to a dispenser, illustrated in its initial position after the stick has been molded. 
           [0031]      FIG. 2  is a longitudinal cross-section of the machine in  FIG. 1  after the molding spacer has been disengaged from the end of the stick. 
           [0032]      FIG. 3  is a longitudinal cross-section of the machine in  FIG. 1 , illustrating the transfer of the stick of lipstick from the molding station to the dispenser. 
           [0033]      FIG. 4  is a longitudinal cross-section of the machine in  FIG. 1 , at the end of its cycle. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    As illustrated in  FIG. 1 , the machine  1  for attaching a stick of lipstick  2  to a dispenser  3  includes an upper station  4  which holds the dispenser  3  and a molding station  5  where the stick of lipstick  2  is molded, as well as an actuator of which only the head  6  is represented. 
         [0035]    The molding station  5  comprises a frame  7  which houses a shell having a wall  8  of deformabie material such as an elastomer, particularly silicone. 
         [0036]    A mold spacer  9  is also housed in the frame  7 , above the deformable wall  8 . The spacer  9  and the deformable wall  8  together form a mold cavity  10  into which a cosmetic product that will constitute the stick of lipstick  2  is poured. The cosmetic product fills the entire internal hollow  10   a  of the deformable wall  8  as well as filling several millimeters of a hole  10   b  through the spacer  9 . 
         [0037]    Advantageously, the machine  1  can comprise a plurality of upper stations  4  mounted on a machine rotating about an axis  4   a  and a plurality of molding stations  5  mounted on a machine rotating about an axis  5   a  parallel to and at a distance from axis  4   a . It is thus possible to introduce the dispenser  3  into an upper station  4  before said station is aligned along axis  11  with one of the molding stations  5 . 
         [0038]    An extraction arm  12  is able to move axially to extract the spacer  9  from the frame  7  and thus disengage the upper end  2   a  of the stick of lipstick  2 . 
         [0039]    As illustrated in  FIGS. 1 and 2 , the extraction arm  12  can be a disk pivoting about axis  5   a  and able to move axially to raise the spacer  9  by its collar  13 . The extraction arm  12  can be pivoted enough to allow a port  27  of the disk to provide free access to the upper end  2   a  of the stick of lipstick  2 . 
         [0040]    The molding station  5  also comprises an outside cavity  36 , extending outside the shell having a deformable wall  8 , and connected to a vacuum pump  37 . 
         [0041]    The upper station  4  will now be described. It is equipped with a retaining head  14  sliding axialiy within a holder  17  due to the action of the actuator head  6  and a return spring  28 . The retaining head  14  has a housing which holds an actuation mechanism  16  of the dispenser  3 . The actuator head  6  may be equipped with a spacer  40  which allows the upper station  4  to adjust to different heights of the actuation mechanism  16 . 
         [0042]    The actuation mechanism  16  comprises a body  18  of the dispenser, a receptacle  19 , and a drive hub  20 . The receptacle  19  comprises an annular wall  19   a  and a bottom  19   b  in which a port  19   c  is arranged. The receptacle  19  also comprises a rear apron  21  having a radially external spur  22  sliding in a helical groove  23  of the body  18  of the dispenser. The helical groove  23  may be a through groove which traverses the wall of the body  18  or may be a blind groove. The rear apron  21  also comprises ribs  24  extending longitudinally along the rear apron  21  and projecting radially inwards, towards the inside of the rear apron  21 . The drive hub  20  has a circular rear groove  25  cooperating with the body  18  of the dispenser so as to be rotatably movable and translationally fixed relative to the body  18  of the dispenser. The drive hub  20  also comprises longitudinal grooves  26  adapted to fit with the longitudinal ribs  24  of the rear apron  21 . Thus, when the drive hub  20  rotates, the receptacle  19  moves in a spiral along the helical groove  23 . This allows the annular wall  19   a  and the bottom  19   b  to change from the “protruding” position illustrated in the figures to a “retracted” position. 
         [0043]    As illustrated in  FIG. 3 , the upper station  4  and the molding station  5  together form a mechanism ( 4 - 5 ) for moving the insertion opening ( 29 ) and the proximal end ( 2   a ) of the stick ( 2 ) adjacent to one another so that the insertion opening ( 29 ) is substantially blocked. In effect, the actuator head  6  and the adjusting spacer  40  descend, press against the top of the retaining head  14 , and drive it downwards while compressing the return spring  28 . 
         [0044]    The actuator head  6  and the adjusting spacer  40  comprise a channel  30  connected to a vacuum pump  31 , and a toroidal gasket  32  surrounds the channel  30 . 
         [0045]    In a variant, the gasket  32  can establish a fluid-tight seal between the adjusting spacer  40  and the retaining head  14 . The retaining head  14 , closed off by the spacer  40 , then forms a chamber  15  containing the major portion of the mechanism  16  and in particular the major portion of the receptacle  19 . 
         [0046]    The retaining head  14  comprises a device  34  for establishing a substantially fluid-tight connection of the chamber  15  to the receptacle  19 . The connecting device  34  comprises a toroidal seal  34   a  extending between the retaining head  14  and the body  18  of the dispenser as well as fitting between the annular wall  19   a  of the receptacle  19  and the body  18  of the dispenser  3 . Thus, a negative pressure created by the vacuum pump  31  is propagated to the chamber  15  via the channel  30 . The negative pressure in the chamber  15  is propagated in turn through the helical grooves  23  and a groove  26   a  in the drive hub  20  to the port  19   c.    
         [0047]    In another variant, the mechanism  16  is like a fluid-tight tube with a central port  41 . The gasket  32  can then press against the top of the actuation mechanism  16 . In this case, the chamber  15  accepting the major portion of the receptacle  19  consists of the fluid-tight body  18 . Similarly to the above variant, the negative pressure of the channel  30  is propagated through the central port  41  of the actuation mechanism  16  to the port  19   c.    
         [0048]    In any of these variants, the annular wall  19   a  of the receptacle  19  has a circular free end defining an opening  29  in the receptacle  19  which is intended for the insertion of the stick  2  into the receptacle  19 . The actuator head  6 , the retaining head  14 , and the actuation mechanism  16  with its receptacle  19  in the “protruding” position, descend until the opening  29  is adjacent to the upper end  2   a  of the stick of lipstick  2 . This position corresponds to the position for transferring the stick  2  from the molding station  5  to the receptacle  19 . 
         [0049]    When the retaining head  14  is in the transfer position, the upper end  2   a  of the stick of lipstick  2  isolates from the outside an area  35  inside the receptacle  19  which communicates with the vacuum pump  31  via the port  19   c.    
         [0050]    The vacuum pump  37  of the molding station  5  creates a negative pressure in the external cavity  36 . The deformable wall  8  of the shell detaches from the stick of lipstick  2  and releases the stick  2 . Thus the negative pressure created within the area  35  inside the receptacle  19  draws the stick of lipstick  2  in. The stick of lipstick can be suctioned in until it rests against the bottom  19   b  of the receptacle  19 . 
         [0051]    The negative pressures created in the receptacle  19  and in the external cavity  36  may be established one before the other, and in any order, but they have at least one period where, simultaneously, the negative pressure in the receptacle  19  is exerting suction on the stick  2  and the negative pressure in the external cavity  36  releases the stick  2 , thus allowing the transfer from the station  5  to the dispenser  3 . 
         [0052]    As illustrated in  FIG. 4 , the retaining head  14  rises to a position where the dispenser  3  to which the stick of lipstick  2  has been attached can be removed from the upper station  4 . 
         [0053]    It is understood that the invention can be implemented with any type of station  5  which is able to retain the stick of lipstick  2 , disengage the end  2   a  of the stick, and release the stick of lipstick  2  when the insertion opening  29  of the receptacle  19  is substantially blocked by the end  2   a.    
         [0054]    Advantageously, a decorative shell (not illustrated) can be assembled to the actuation mechanism  16  by hooking it onto the drive hub  20 . This last step in the method for assembling the lipstick dispenser can be performed away from the stick of lipstick attachment machine  1  described above. This prevents scratches and allows on-demand inventory management. 
         [0055]    The method of the stick of lipstick attachment machine  1  is particularly advantageous for stick of lipstick  2  consisting of a soft cosmetic paste. It can also be used with cosmetic pastes of the usual hardness but having a particularly fragile contour where it touches the lips. 
         [0056]    In one variant of the attachment method, the retaining head  14  can descend until the opening  29  of the receptacle  19  is level with the silicone wall  8  or until the end  2   a  of the stick of lipstick  2  reaches the bottom  19   b  of the receptacle  19 . It is possible to only activate the vacuum pump  31  when conventional nesting would deform the stick of lipstick  2 , in particular the contour of the end which is applied to the lips. 
         [0057]    In another variant, the machine  1  can be used to adjust the position of the stick of lipstick in the receptacle  19  of the dispenser by creating in the receptacle  19  a positive pressure or a negative pressure relative to the atmospheric pressure. In this variant, the channel  30  or the chamber  15  can also be connected to a compressed air generator (not represented) via a controllable three-way valve. 
         [0058]    The machine  1  can be used with any actuation mechanism having a port  19   c  opening into the area  35  inside the receptacle and not blocked off when the introduction of the stick  2  begins. 
         [0059]    The bullet attachment and molding machine can comprise a single upper station  4  and/or a single molding station. 
         [0060]    In one variant, the vacuum pump  31  can be connected directly to the chamber  15 .

Technology Category: 4