Abstract:
A cosmetic stick has a stick housing, a refill extendable therefrom out of a refill opening as well as a feed device for extending the refill. The refill is in push connection with a piston guided in the housing. The feed device has a piston push rod and an actuating push rod. Said actuating push rod is in push connection with an actuating element. The actuating push rod is in push connection with the piston push rod via a pair of stops. A stop alternating device allows alternation between the first stop and one of a plurality of second stops. The stop alternating device has a driver body fixed to the actuating push rod. A ramp cooperates with the driver body. The ramp incline is such that the first stop disengages from the instantaneous second stop as soon as the driver body has covered an advance path which is at least identical to the distance between two adjacent second stops. A pretensioning spring biases the actuating push rod in an unactuated rest position. A cosmetic stick is produced, the production costs of which are reduced with a given operational reliability of the stop alternating device.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a cosmetic stick with a stick housing, with a refill which may be moved out of the housing through a refill opening, with a feed device positioned in the housing for extending the refill, wherein the refill is in push connection with a piston guided in the housing, wherein the feed device comprises a piston push rod in push connection with the piston and positioned on the side of the piston remote from the refill, wherein the feed device further comprises an actuating push rod in push connection with an actuating element positioned on an end, opposite the refill opening, of the actuating push rod, wherein the actuating push rod is in push connection with the piston push rod via a pair of stops consisting of a first stop positioned on one of the two push rods, and a plurality of second stops positioned successively at an equal distance from one another axially along the other push rod, with a stop alternating device with which the first stop alternates between a second instantaneous stop of the second stops, with which the first stop instantaneously cooperates, and an axially adjacent second target stop, to advance the refill. 
         [0003]    2. Background Art 
         [0004]    A cosmetic stick of this type is known from U.S. Pat. No. 5,011,317 A. The stop alternating device in the aforementioned US patent is of a complex construction and imposes exacting requirements on the manufacturing tolerances and on the precise observance of the material parameters of the components involved to ensure reliable operation. 
       SUMMARY OF THE INVENTION 
       [0005]    It is therefore an object of the present invention to develop a cosmetic stick of the type mentioned at the outset, such that the production costs are reduced with a given operational reliability of the stop alternating device. 
         [0006]    This object is achieved according to the invention by a cosmetic stick having a stop alternating device comprising a driver body fixed to the actuating push rod, at least one ramp fixed to the housing and cooperating with the driver body, the ramp incline of said ramp being such that in an actuating position of the actuating push rod, the first stop disengages from the instantaneous stop as soon as the driver body has covered an advance path which is at least identical to the distance between two adjacent second stops, a pretensioning spring which biases the actuating push rod relative to the housing in an unactuated rest position in which the actuating element is pushed out of the housing. 
         [0007]    It has been found according to the invention that a reliable stop alternation may be achieved using two cooperating actuating push rods, in that a relative movement between the two stops instantaneously together forming a pair of stops is intentionally produced by positively driving one of the two push rods over a ramp. In so doing, one drive rod is deflected with a movement component transversely to the longitudinal axis thereof during the positive driving. No standard model exists for this in the prior art. Overall, this allows a cosmetic stick with a housing construction in which the risk of sink marks caused by differences in the housing wall is minimised. The individual components of the cosmetic stick may be simply produced as injection moulded plastics material parts. Alternatively, it is possible to produce the stick housing and also a cap for covering the refill opening as metal components. Special tools for assembling the cosmetic stick, in particular screwing out tools for housing components or push rods are not required. 
         [0008]    A distribution of the stops with the first stop being positioned on the actuating push rod and the second stop being positioned on the piston push rod provides a simple construction of the feed device. Alternatively, it is possible to provide the first stop on the piston push rod and the second stops on the actuating push rod. 
         [0009]    A cosmetic stick in which the driver body has the first stop provides a compact construction of the feed device, since the functions of “ramp guidance” and “first stop” are combined in a compact manner on the driver body. 
         [0010]    Contact portions where the push rods engage which are formed such that a return of the actuating push rod from the actuating position into the rest position is possible by the push rods sliding past one another, without the piston push rod being axially displaced relative to the housing as a result ensure that the piston push rod is not entrained, which is undesirable, during the return of the actuating push rod from the actuating position into the rest position. Securing the piston push rod in this manner may be further assisted by a corresponding friction of the piston push rod in a guide means provided through a passage opening in a component fixed to the housing. 
         [0011]    A pretensioning spring being configured as a plastics material spring provides a simple construction of the cosmetic stick. The plastics material spring may also be produced as an injection moulded part and may integrate various functions. Thus, the plastics material spring may have in particular an intermediate bottom into which the passage opening is guided for guiding the movement of the piston push rod. When a plastics material pretensioning spring is used, a bayonet catch in particular is possible for joining on the one hand a cosmetic product housing portion, i.e. a refill housing portion, with on the other hand a feed housing portion, without openings of this connection which are required in terms of production consequently being visible from outside. A metal spring is not used. 
         [0012]    A ramp being formed integrally with the pretensioning spring also enhances the compact nature of the arrangement, since an additional function integration takes place. 
         [0013]    A guide means for guiding the axial movement of the push rods relative to one another provides a reliable and defined relative movement of the push rods during the feed activation. 
         [0014]    A cup-shaped seat in the piston holding the refill ensures that the refill is held securely and also allows the cosmetic stick to be equipped in a simple manner with the refill. 
         [0015]    Embodiments of the invention will be described hereinafter with reference to the drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  shows a perspective view of a cosmetic stick; 
           [0017]      FIG. 2  shows a longitudinal section through the cosmetic stick according to  FIG. 1 ; 
           [0018]      FIG. 3  shows comparable to an exploded view all the individual components for assembling the cosmetic stick according to  FIG. 1 ; 
           [0019]      FIG. 4  shows a perspective view of a cosmetic product replacement unit for a base stick module of the cosmetic stick according to  FIG. 1 to 3 ; 
           [0020]      FIG. 5  shows an axial longitudinal section through the cosmetic product replacement unit according to  FIG. 4 ; 
           [0021]      FIG. 6  shows a view of the cosmetic product replacement unit similar to that of  FIG. 3 ; 
           [0022]      FIG. 7  shows a perspective side view of another cosmetic stick with a different base stick module having a feed device for the cosmetic product, said feed device differing in respect of its mechanical active principles from the feed device of the base stick module of the cosmetic stick according to  FIG. 1 ; 
           [0023]      FIG. 8  shows an axial longitudinal section of the cosmetic stick according to  FIG. 7 ; and 
           [0024]      FIG. 9  shows a view, similar to  FIG. 3 , of the individual components of the cosmetic stick according to  FIG. 7 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    A cosmetic stick  1  has a stick housing  2  with a cosmetic product housing portion  3  and a feed housing portion  4 . The stick housing  2  with the cosmetic product housing portion  3  is produced from SAN-ABS. The cosmetic product housing portion  3  has a cone housing body  5  which is covered by a cap  6 , for example when the cosmetic stick  1  is stored.  FIG. 2  shows the cap  6  pushed onto the cone housing body  5 , said cap  6  abutting against a peripheral collar  7  of the cone housing body  5 . A slight undercut (not shown in more detail) of the cone housing body  5  and of the cap  6  ensure that the cap  6  is held with a positive fit, and thus secured, on the cone housing body  5  when resting on the peripheral collar  7 . At the same time, a user may easily remove the cap  6  from the cone housing body  5 . 
         [0026]    Adjacent to the peripheral collar  7 , the cone housing body  5  has bayonet segments  8  which face the feed housing portion  4  and catch in a corresponding inner peripheral recess in the feed housing portion  4  when the cone housing body  5  is assembled. The bayonet segments  8  form together with the corresponding bayonet seat in the feed housing portion  4  a bayonet catch for joining these two housing components. A catch connection is also possible instead of a bayonet catch. 
         [0027]    A cosmetic product in the form of a refill  9  is positioned in the cone housing body  5 . Said refill  9  may be moved out of the cone housing body  5  through a refill opening  10 . A feed device  11  which is housed in the feed housing portion  4  and will be described in more detail hereinafter is used to extend the refill  9 . 
         [0028]    The refill  9  is in a push connection with a piston  12  guided in the cone housing body  5 . In this respect, the refill  9  is held in a cup-shaped seat of the piston  12 . The refill  9  has a diameter of 6 mm. The seat of the piston  12  has an inner diameter corresponding thereto. Other refill diameters are also possible. A refill diameter of 8 mm in particular is also possible. Formed on the piston  12  is a piston connecting component  13 , the outer diameter of which is reduced in comparison to the outer diameter of the rest of the piston  12 . Peripheral seats of a sleeve-shaped connecting component  14  of a piston push rod  15  are formed in complementary manner to bayonet segments of the piston connecting component  13 . The piston push rod  15  is made of POM. The piston push rod  15  is in push connection with the piston  12  and is positioned on the side of the piston  12  remote from the refill  9 . A positive, secure connection between the piston  12  and the feed device  11 , to which the piston push rod  15  belongs, is produced via the bayonet connection formed by the connecting components  13  and  14 . 
         [0029]    An actuating push rod  16  also belongs to the feed device  11 . Said actuating push rod  16  is in push connection with the piston push rod  15 . The actuating push rod  16  is made of POM. Said push connection is produced via a pair of stops consisting of a first stop  17  positioned on the actuating push rod  16  and a plurality of second stops  18  positioned in succession at an equal distance from one another axially along the piston push rod  15 . In the feed position shown in  FIG. 2 , the first stop  17  of the actuating push rod  16  cooperates with the second stop  18  in the furthest left-hand position shown in  FIG. 2 , so that the refill  9  is in a starting position with the piston  12  fully retracted into the stick housing  2 . 
         [0030]    Overall, there are two rows of second stops  18  at the same height, between which runs the actuating push rod  16 . Where the actuating push rod  16  runs between the two rows of second stops  18  up to the piston push rod  15  facing the stop point  19 , the two push rods  15 ,  16  are guided towards one another, so that a defined relative movement of the two push rods  15 ,  16  with respect to one another is possible. This guidance is carried out by a complementary cross-sectional configuration of adjacent portions of the push rods  15 ,  16 . This guide means is a T groove guidance. 
         [0031]    On its side remote from the piston  12 , the actuating push rod  16  has a contact peripheral collar  19 . The outer diameter of the contact peripheral collar  19  corresponds to the inner diameter of the feed housing portion  4 . A free end  20 , adjacent to the contact peripheral collar  19 , of the actuating push rod  16  bears an operating button  21  as actuating element which is latched onto the free end  20 . The operating button  21  protrudes, like an operating button for a ballpoint pen, out of the end, opposite the refill  9 , of the feed housing portion  4 . Latched into a housing opening in the feed housing portion  4 , from which the operating button  21  protrudes, is a stopper  22  which is shaped like a sleeve and is penetrated by the operating button  21 . The operating button  21  is made of SAN-ABS, as is the stopper  22 . An inner end wall of the stopper  22  rests against the contact peripheral collar  19  of the actuating push rod  16 . A plastics material pretensioning spring  23  rests against the contact peripheral collar  19  on the side opposite the stopper  22 . The plastics material pretensioning spring  23  is made of POM. At its opposite free end, the plastics material pretensioning spring  23  is supported against an inwardly projecting peripheral collar  24  of the feed housing portion  4 . This peripheral collar  24  is closely adjacent to a dividing line between the feed housing portion  4  and the cone housing body  5 . 
         [0032]    The plastics material pretensioning spring  23  has an intermediate bottom  25  adjacent to the end wall of the free end, carrying the bayonet segment  8 , of the cone housing body  5 . Said intermediate bottom  25  has an approximately rectangular passage opening  26  through which the piston push rod  15  passes. 
         [0033]    A stop alternating device  27  is a component of the feed device  11 . To advance the refill  9 , the stop alternating device  27  alternates the first stop  17  between one of the second stops  18 , with which the first stop  17  instantaneously cooperates and which is also called the second instantaneous stop, and an axially adjacent other second stop  18  which is also called the target stop. The stop alternating device has a driver body  28  formed on the free end facing the piston  12 , of the actuating push rod  16 . The driver body  28  supports the two first stops  17 , positioned at the same height, on both sides like wing stumps. 
         [0034]    A ramp  29  cooperates with the driver body  28 . Said ramp  29  is configured in the intermediate bottom  25  of the plastics material pretensioning spring  23  which in turn is fixed on the feed housing portion  4 . The ramp  29  is therefore fixed on the stick housing  2 . 
         [0035]    The plastics material pretensioning spring  23  also belongs to the stop alternating device  27 . The second stops  18  positioned axially behind one another and at an equal distance from one another are configured in the manner of saw teeth. The flank of this saw tooth configuration which is steep in each case and vertical in practice forms the second stops  18 . Oblique wall portions  13  run between these perpendicular wall portions. The incline of these oblique wall portions  30  with respect to a longitudinal axis of the stick housing  2  is sufficiently low for the wing stumps of the driver body  28  to be able to push on the oblique wall portions  30  in a direction opposite the feed direction, without the piston push rod  15  being axially displaced relative to the stick housing  2  as a result. 
         [0036]    The cosmetic stick  1  is assembled as follows: 
         [0037]    First of all, the plastics material pretensioning spring  23  is pushed into the feed housing portion  4  until it meets the stop collar  24 . A ridge on the stopper side of the feed housing portion  4  cooperating with a corresponding groove in the periphery of the plastics material pretensioning spring  23  ensures that the plastics material pretensioning spring  23  can be pushed into the feed housing portion  4  only in a predetermined orientation. The inner diameter of the feed housing portion  4  is coordinated with the outer diameter of the plastics material pretensioning spring  23 , such that both parts easily clamp together in the assembly end position. The piston push rod  15  is then introduced into the plastics material pretensioning spring  23 . This is carried out from the left-hand side in  FIG. 2 . In this respect, the position and the cross section of the passage opening allow only a correct introduction orientation of the piston push rod  15  into the plastics material pretensioning spring  23 . Said piston push rod  15  is introduced into the plastics material pretensioning spring  23  until the push rod connecting component  14  of the piston push rod  15  abuts against the intermediate bottom  25  of the plastics material pretensioning spring  23 . The actuating push rod  16 , already provided with the attached operating button  21 , is then inserted into the feed housing portion  4  from the right-hand side in  FIG. 2  and threaded in terms of guidance into the complementary guidance of the piston push rod  15 . When the actuating push rod  16  is pushed into the feed housing portion  4 , the first stop  17  of the actuating push rod  16  engages initially with the second stop  18 , in the furthest right-hand position in  FIG. 3 , of the piston push rod  15 . During further insertion, the actuating push rod  16  pushes the piston push rod  15  ahead of it until the driver body  28  of the actuating push  16  runs onto the ramp  29 . In so doing, the first stop  17  disengages from the second instantaneous stop  18 . The piston push rod  15  may then be pushed back to the right-hand side in  FIG. 2  until it reaches the starting position. The stopper  22  is then pushed and latched into the feed house portion  4 . In so doing, the plastics material spring is lightly biased between the peripheral collar  19  and the peripheral collar  24 . 
         [0038]    When the operating button  21  is actuated, in other words when the operating button  21  is pushed into the stick housing  2 , the piston push rod  15  is advanced by the actuating push rod  16  through the engagement of the first stop  17  with a second instantaneous stop  18 , initially by an advance path which at least equals the distance between two second stops  18 . After this advance path, the driver body  28  has run onto the ramp  29  to such an extent that the first stop  17  disengages from the second instantaneous stop  18 . Further advance of the piston push rod  15  therefore does not take place, irrespective of whether the operating button  21  is pressed further into the stick housing  2 . When the operating button  21  is released, it is pushed back again into the rest position shown in  FIG. 2  due to the bias of the plastics material pretensioning spring  23  until the peripheral collar  19  rests against the stopper  22 . During this pushing back action, the driver body  28  pushs on the oblique wall portions  30  of the piston push rod  15 . In so doing, the piston push rod  15  is not displaced axially relative to the stick housing  2 , such that in the rest position of the operating button  21 , the first stop  17  is then able to engage with the second target stop  18  which is axially adjacent to the previous second instantaneous stop  18 , more specifically is axially adjacent on the right-hand side in  FIG. 2 . 
         [0039]      FIG. 4 to 6  show a cosmetic product replacement unit  31  for a base stick module  32  of the cosmetic stick  1 . The base stick module  32  includes all the components of the cosmetic stick  1  except for the cosmetic product housing portion  3 , the piston  12  and the refill  9 . 
         [0040]    The cosmetic product replacement unit  31  has a replacement housing  33  which is identical to the cosmetic product housing portion  3 , i.e. it has the cone housing body  5  and the cap  6 . A sealing cap  34  positioned on the replacement housing  33  and secured thereto via a bayonet catch seals the replacement housing  33  on the side of the piston  12 . The sealing cap  34  is made of polypropylene (PP). A support  35  formed on the base of the sealing cap  34  in the region of the stick housing longitudinal axis is used for the defined contact of the piston connecting component  13 . Positioned in the replacement housing  33  of the cosmetic product replacement unit  31  are the refill  9  and the piston  12  in the same orientation and position to the cone housing body  5  as in the cosmetic product housing portion  3  of the cosmetic stick  1 . 
         [0041]    The cosmetic product replacement unit  31  is assembled as follows: first of all the piston  12  is pushed with guiding seat opening leading into the cone housing body  5 , more specifically from the side on which the bayonet segments  8  are located on the cone housing body  5 . Ridges  36  formed on the outer wall of the piston  12  run in this respect in axial grooves in the inner wall of the cone housing body  5 , such that the piston  12  is safeguarded against twisting in the cone housing body  5 . A latching formed by complementarily formed latch elements on the piston  12  on the one hand and on the cone housing body  5  on the other hand indicates the assembly end position of the piston  12  in the cone housing body  5 . The sealing cap  34  is then fitted on the cone housing body  5  via the bayonet connection. The refill  9  is then introduced into the seat in the piston  12  and finally the cap  6  is placed on the cone housing body  5 . 
         [0042]    To replace a cosmetic product housing portion  3  with a new cosmetic product replacement unit  31  when the refill  9  is used up, the bayonet connection between the cosmetic product housing portion  3  and the feed housing portion  4  is released. The sealing cap  34  is removed from the cosmetic product replacement unit  31  and said replacement unit  31  is connected to the feed housing portion  4  of the cosmetic stick  1 . In so doing, a bayonet connection is simultaneously produced between the replacement housing  33  and the feed housing portion  4  on the one hand and between the piston connecting components  13  and the push rod connecting component  14 . The cosmetic stick  1  is then ready for use again with a new refill  9 . 
         [0043]      FIG. 7 to 9  show another variant of a cosmetic stick, wherein the cosmetic product replacement unit  31  may also be used. Components corresponding to those previously described hereinbefore with reference to  FIG. 1 to 6  have been given the same reference numerals and will not be described again in detail. 
         [0044]    A base stick module  37  of the cosmetic stick according to  FIG. 7 to 9  has a feed device  38  with an actuating wheel  39 . A circumferential portion of said actuating wheel  39  protrudes out of a feed housing portion  40  of the cosmetic stick  1  according to  FIG. 7 to 9 . The actuating wheel  39  is made of SAN-ABS as is the feed housing portion  40 . Gear wheels  42  are formed integrally in each case with the actuating wheel  39  on bearing journals  41  guided on both sides out of the actuating wheel  39 . The gear wheels  42  mesh with two rack portions  43 , running parallel to each other, of a piston push rod  44  of the cosmetic stick  1  according to  FIG. 7 to 9 . The piston push rod  44  is made of POM. Formed integrally with the rack portions  43 , facing the piston  12 , is the push rod connecting body  14  which is configured identically to the piston rod connecting body  14  of the embodiment according to  FIG. 1 to 3 . The piston push rod  14  here again passes through the passage opening  26  in the plastics material pretensioning spring  23 . 
         [0045]    The bearing journals  41  of the actuating wheel  39  are latched into latch seats  45  of a screen housing portion  46 . The screen housing portion  46  is made of SAN-ABS. Said screen housing portion  46  which surrounds the actuating wheel  39  is here again latched into a mounting in the feed housing portion  40 . 
         [0046]    For the assembly of the cosmetic stick  1  according to  FIG. 7 to 9 , the plastics material pretensioning spring  23  is also initially introduced into the feed housing portion  40 , as described in connection with the assembly of the cosmetic stick  1  according to  FIG. 1 to 3 . The stopper  22  is then pushed from the right-hand side in  FIG. 8  into the feed housing portion  40  and is latched therein. The piston push rod  44  is then introduced into the plastics material pretensioning spring  23  through the passage opening  26  from the left-hand side in  FIG. 8 . The actuating wheel  39  is latched into the latch seat  45  in the screen housing portion  46  and the screen housing portion  46  is then latched into the seat in the feed housing portion  40 . The refill  9  may be pushed out of the refill opening  10  or may be pushed back again into the stick housing  2  by turning the actuating wheel  39 . 
         [0047]    In both embodiments, i.e. in the embodiment according to  FIG. 1 to 3  with the operating button  21  to advance the refill and in the embodiment according to  FIG. 7 to 9  with the actuating wheel  39  to advance the refill, the profile cross-section of the piston push rod  15  and  44  is coordinated with the inner cross-section of the passage opening  26  in the plastics material pretensioning spring such that a friction action occurs in the guidance through the passage opening  26  during the movement of the piston push rods  15  and  44 . In the embodiment according to  FIG. 1 to 3 , this friction is greater than the friction between the piston push rod and the actuating push rod  16 . This contributes to the fact that the piston push rod  15  is not entrained by the activating push rod  16 , which is undesirable, during the return of the actuating push rod  16  from the actuating position into the rest position. In the embodiment according to  FIG. 7 to 9 , the effect of the friction between the piston push rod  44  and the inner wall of the passage opening  26  is that a certain axial pressure may be exerted on the refill  9  during use, without this resulting in the refill  9  being pushed back undesirably into the stick housing  2 .