BACKGROUND OF THE INVENTION  
         [0001]    It is known to combine the screw cap of a nail polish bottle with an applicator brush. The cap functions as a closure for the bottle and as a handle for the applicator brush. However, prior art nail polish bottle caps are not well suited for use as the handle of an applicator brush.  
           [0002]    In particular, the relatively small size of the cap compromises handling and control of the applicator brush. A small cap may only be grasped between the fingertips of the user and as a result, translational slip of the fingertips along the longitudinal axis of the cap occurs. This type of slip makes it difficult for the user to uniformly apply a detailed brush stroke onto the small surface area of a fingernail. In addition, the applicator cap of prior art nail polish bottles will have a non-angular transverse cross section i.e. it is round or otherwise provided with a curved surface. This curvature contributes to rotational slip of the fingertips as the cap is twisted onto or off of the bottle. Threading the cap on the bottle is especially difficult when nail polish applied to the users nails has not fully dried and the cap is being held lightly between the users fingertips.  
           [0003]    Anatomical differences among users may also contribute to a poor grip on the applicator cap. Variation in finger size and shape means different users grasp the cap at different locations along the length of the cap in an effort to optimize their grip. A user having short and thin fingers is more likely to grasp and squeeze the cap near the end secured to the brush whereas a user having larger fingers may find it necessary to grip the cap at a more central location or further away from the end secured to the brush. As is apparent, grasping the cap at different locations along the length of the cap affects the grip on the cap and therefore control of the brush stroke.  
           [0004]    Fatigue is yet another problem. To achieve a smooth brush stroke and uniform application of a coating of polish, a user tends to squeeze the cap. This application of pressure by the fingertips against the cap functions to stabilize the users hold as the user effects a sweeping motion with their hand. Repeatedly applying and releasing pressure against the cap will eventually cause fatigue and discomfort.  
           [0005]    The material from which the cap is constructed also contributes to fatigue and a poor grip. Nail polish bottle caps are constructed from rigid and hard plastics. The exterior surface of a cap constructed from hard and inflexible materials is uncomfortable to hold over any extended period of time and as noted earlier, when the cap is repeatedly squeezed between the fingertips during use, the hard surfaces accelerate the feeling of discomfort and fatigue. Although the exterior surface of some prior art caps may be provided with ridges or similar raised structures in an effort to improve the grip against the hard and smooth surface of the cap, such efforts are known to diminish comfort.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0006]    It is an object of the invention to provide a container for nail polish having an applicator cap the exterior of which is provided with a nonrigid material adapted to eliminate rotational and translational slip during grasping of the cap, increase comfort during use, improve the quality of the brush stroke by improving dexterity and also reduce fatigue.  
           [0007]    It is a further object of the present invention to provide a container for nail polish having a applicator cap exterior surface that is compressible so as to provide increased control of the brush stroke.  
           [0008]    A still further object of the present invention is to provide a method for applying nail polish to a surface.  
           [0009]    The present invention is directed to a container and cooperating applicator cap comprising a bottle for containing a material to be dispensed, the bottle having an opening for access to material contained therein and a cap for sealing engagement with the opening of the bottle, the cap comprising a rigid base member, an applicator brush fixed to the base member and aligned along the longitudinal axis thereof, an overshell of compressible material disposed on the base member, the overshell providing a gripping surface on said cap.  
           [0010]    Other objects and advantages will be apparent from the following description and claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a perspective view of an applicator cap of the present invention in combination with a nail polish bottle;  
         [0012]    [0012]FIG. 2 is a cross-sectional view taken along lines  2 - 2  of FIG. 1 with portions of the applicator brush broken away;  
         [0013]    [0013]FIG. 3 is a partially exploded view of the cap shown in FIG. 1;  
         [0014]    [0014]FIG. 4 is perspective view of another embodiment of the cap and bottle according to the present invention;  
         [0015]    [0015]FIG. 5 is a cross-sectional view taken along lines  5 - 5  of FIG. 4 with portions of the applicator brush broken away;  
         [0016]    [0016]FIG. 6 is a perspective view of another embodiment of the applicator cap and bottle according to the present invention; and  
         [0017]    [0017]FIG. 7 is a partially exploded view of the cap shown in FIG. 6. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    [0018]FIG. 1 illustrates one embodiment of the combination bottle and applicator cap according to the present invention, the cap C shown in alignment for interconnection with the neck of a nail polish bottle B.  
         [0019]    As best shown in FIG. 2 and  3 , cap C includes a base member  2  preferably constructed from a material having sufficient rigidity so that the cap C may be firmly threaded onto the neck of a nail polish bottle B. In a preferred embodiment, the base member  2  is constructed from ABS plastic, polypropylene, nylon or another rigid, inflexible material. ABS, polypropylene and nylon are preferred materials not only because they are relatively rigid and inflexible, but also because they have been found to form a good bond with the soft overshell material discussed below. Suitable polypropylene material may be obtained from BASF of Germany. The base member  2  includes an exterior side wall  16 , a flange member  18  is provided at a lower end of the base member and a top surface  10  is provided at an opposite, upper end of the base member. Raised indicia  6  extends from top surface  10  and may take the form of a decorative marking such as a company logo or other printing. As is apparent, the raised indicia  6  is optional. An interior side wall  20  extends upwardly within base member  6  and terminates at an interior top surface  24 . A portion of interior side wall  20  is provided with female threads  22  adapted to interconnect with the male threads of bottle B. It is within the scope of the present invention to vary the length of interior side wall  20 . For example, the interior side wall  20  may be lengthened so that interior top surface  24  is disposed adjacent top surface  10  of base member  2 . Interior top surface  24  is shown in the drawings to include a transversely extending post member  26  configured to be fixedly received within an end  28  of shaft  30 . The opposite end of shaft  30  is provided with a brush  32 . Various other embodiments for securing the shaft of the applicator brush to the base member  2  are within the scope of the present invention. For example, rather than rendering the shaft end  28  integral with the shaft  30  as shown in the drawings, a separate connector may be provided that is adapted to be press fitted against the interior side wall  20  of base member  2  and connected to an end of shaft  30 .  
         [0020]    A non-rigid cover or overshell member  34  is provided on the exterior of rigid base member  2 . The overshell member  34  provides a highly tactile and soft material disposed between the user and the rigid portions of the cap and applicator brush. This non-rigid exterior surface enhances the users grip with the cap to reduce or eliminate rotational and translational slippage, provides a damping effect which improves application of the polish from the brush to the nail surface and can be combined with a generally concave surface contour to reduce fatigue during use of the brush. The improvement in overall manual dexterity when using the cap of the present invention will result in a higher quality of brush stroke and application of polish that is substantially improved over that provided by the rigid prior art applicator cap devices.  
         [0021]    The non-rigid overshell member is preferably formed from a thermoplastic elastomer material and in at least one embodiment has a shore value of about twenty-nine to about ninety-six and a thickness of about 1 mm to about 3 mm. In a preferred embodiment, the overshell will have a shore value of about forty-five and a thickness between about 1.5 mm to about 3.0 mm. As is apparent, a variety of thicknesses for the overshell material can be provided. For example, the overshell may be applied in a uniform thickness or varied in thickness along the length of the cap. The soft overshell may also be constructed from silicon rubber or other materials adapted to provide the shore values listed and/or function in the manner as required in this disclosure. Applicant has discovered that a thermoplastic elastomer material will form a good bond with the above noted materials used to form the rigid base member.  
         [0022]    The thermoplastic elastomer as set forth above provides an applicator cap having an exterior surface of sufficient feel and resiliency so that not only is surface friction increased and the users grip on the cap improved; but also, unsteady or unwanted movement of the brush as it contacts the surface will be caused to be damped and minimized. The damping is effected by the slight deflection of the thermoplastic elastomer material forming the overshell. That is, as the cap is held and the brush is stroked against the surface of a nail, the overshell material is adapted to slightly compress against the users fingers to moderate movement of the brush on the nail surface and thereby provide a more steady and uniform brush stroke. The overshell function to reduce translational slip of the cap between the users fingers as the brush is used to apply polish to a surface and rotational slip as in the case where the cap is being twisted onto or off of a bottle.  
         [0023]    In a preferred embodiment, the thermoplastic elastomer obtained (Advanced Elastomer Systems) is sold and marketed under the trademark SANTOPRENE. Another preferred thermoplastic elastomer may be obtained from Gummiwerk Kraiburg of Germany and is sold and marketed under the trademark THERMOLAST K. A material other than a thermoplastic elastomer is within the scope of the present invention so long as it provides the softness and damping characteristics as set forth above and achieves a high quality bond with the material comprising the underlying base member  2 .  
         [0024]    Overshell member  34  is preferably adhered to the rigid base member  2  using injection molding and in particular, injection molding in accordance with a co-extrusion process. This process employs a mold adapted to receive and cure two separate materials. For to example, a polypropylene material is injected into a rotating mold (not shown) to form the rigid base member  2 , the mold is then rotated to a second position and a thermoplastic elastomer is injected to form the overshell member. Other processes are within the scope of the present invention provided good adhesion is obtained between the overshell and the base member.  
         [0025]    Returning to the drawings and in particular FIG. 2, overshell  34  is shown to not entirely cover the exterior of the rigid base member  2 . That is, raised indicia  6  on base member  2  extends through openings  36  of overshell  34 . As noted above, this indicia may take the form of a logo or other writing and is of course optional. The exterior surface of flange member  18  is likewise shown to not be covered by overshell  34  and as shown in the drawings, forms a continuous or coplanar surface with the exterior surface of the overshell. Flange member  18  is shown to extend laterally from the bottom  38  of cap C to provide an end that is rigid; however, it is within the scope of the present invention to remove or otherwise modify the flange in view of aesthetic or functional requirements.  
         [0026]    In another embodiment of the present invention as best shown in FIGS. 1, 2 and  3 , the exterior sidewall  39  of overshell  34  has a concave shape so that the overall thickness of the overshell is variable along the longitudinal axis of cap C. Arrows  40  and  42  indicate the regions of the overshell having increased thickness whereas arrow  44  indicates the region of the overshell having a lesser thickness. At least one advantage provided by the concave configuration is an ergonomic fit against the fingertips of a user. If the cap is grasped centrally (at about arrow  44 ) between a pair of opposed fingers (or ends thereof) of the users hand, and a stoke of the brush is effected against the fingernail surface, the thicker regions of the overshell (at about arrows  40  and  42 ) are caused to be compressed and/or flexed thereby damping the brush stroke and promoting smoother more uniform application of the polish. The compression and/or flexing of the overshell may also occur when the user grasps the cap at or near the end portions identified by arrows  40  and  42  as in the case with a user having a larger or smaller than average finger size. The overshell also functions to diminish translational and rotational slip of the cap as the concave sidewall of the cap is grasped between the ends of the users fingers. Rotational slip is a significant problem since nail polish caps almost uniformly are provided with a non-angular transverse cross section. Although the base member  2  is shown in the drawings to have substantially cylindrical shape, it is within the scope of the present invention to provide a concave or other shape for the surface of the exterior side wall  16 .  
         [0027]    Turning to FIGS. 4 and 5, another embodiment of the present invention is shown. In the embodiment of FIGS. 4 and 5, base member  2  is preferably constructed from a material having sufficient rigidity so that the cap C may be firmly threaded onto the neck of the cooperating nail polish bottle (not shown). As in the earlier embodiments, the base member  2  is preferably constructed from ABS plastic, polypropylene, nylon or another rigid, inflexible material that is compatible with the overshell. The base member  2  includes an exterior side wall  16 , a flange member  18  is provided at a lower end of the base member and a top surface  10  is provided at an opposite, upper end of the base member. Optional raised indicia  6  is shown to extend from top surface  10  and may take the form of a decorative marking such as a company logo or other printing. An interior side wall  20  extends upwardly within base member  6  and terminates at an interior top surface  24 . A portion of interior side wall  20  is provided with female threads  22  adapted to interconnect with the male threads of a bottle (not shown). As in the earlier embodiments, it is within the scope of the present invention to vary the length of interior side wall  20 . Also note in this embodiment, the cap does not have a concave shape but is provided with a uniform diameter throughout. Interior top surface  24  is shown in the figure to include a transversely extending post member  26  configured to be fixedly received within an end  28  of shaft  30 . The opposite end of shaft  30  is provided with a brush  32 . Other embodiments for securing the shaft of the applicator brush to the base member are within the scope of the present invention. In the embodiment of FIGS. 4 and 5, a non-rigid overshell member  35  is provided on the exterior of rigid base member  2 . As in the other embodiments, the overshell member  35  provides a highly tactile and soft material disposed between the fingers of the user and the relatively rigid remaining portions of the cap and applicator brush. The non-rigid exterior surface of the overshell  35  enhances the users grip on the cap by reducing translational and rotational slip as well as improves application of polish from the brush to the nail surface and also functions to reduce fatigue while holding the cap. The exterior of the overshell  35  is provided with indentations or dimples  46  to further enhance the users grip on cap C. It is within the scope of the present invention to provide different surface modification, including but not limited to raised bumps or the like. While it is understood provision of indentations  46  will provide a variable thickness for overshell  35 , it is within the scope of this embodiment to eliminate the indentations (as in the FIG. 2) and provide an overshell  35  having substantially uniform thickness. In such an embodiment, it is understood that the overshell  35  may be sufficiently thick so as to provide the compression and/or flexing as set forth above together with the improved grip surface. In the alternative, the overshell thickness can be lessened and rendered not compressible or flexible in which case the overshell will function to enhance the grip on the cap by providing the anti-slip characteristic.  
         [0028]    [0028]FIGS. 6 and 7 illustrate another embodiment of the invention whereby at least a portion of the exterior side wall  16  is shown to project through the exterior side wall  39  of overshell  34 . That is, projection or flange  19  extends from the exterior side wall  16  such that a portion  21  remains uncovered by overshell  25 . Various other configurations showing discontinuous side wall surfaces of alternating rigid and non-rigid material are within the scope of the present embodiment. In addition to the above, the flange  19  which does not fully extend around the circumference of base member  2 , provides an abutment  23  against which overshell portion  33  will contact. The contact of the overshell against the flange reduces the likelihood of separation of the overshell from the base member due to torque generated during twisting of the cap onto and off of a bottle.  
         [0029]    It is also within the teaching of the present invention to provide separable cap portions  2  and  4  which may be separately formed and then glued together or otherwise joined together to provide a unitary cap C. Further, it is within the scope of the present invention to provide indicia or some other design within the side walls  14  of top cap  4  thereby providing a discontinuous side wall surface having discrete areas of soft and compressible material and separate discrete areas of rigid material continuous with the underlying base cap. This would of course provide a cap C having an enhanced gripping surface limited to certain exterior portions of the cap.  
         [0030]    It is also within the scope of the present invention to provide other materials for use as the overshell. Although the cap may be injection molded with separate materials as set forth above, it may also be injection molded from a single material that increases in density or softness from the interior cap to the exterior surface to thereby provide a rigid underside for support and a good connection with the bottle and the soft and resilient exterior having the gripping and damping characteristics of the present invention.  
         [0031]    While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.
A combination container and applicator cap comprising a bottle or reservoir for containing a material to be dispensed, the bottle having an opening for access to material contained therein and a cap for sealing engagement with the opening of the bottle, the cap comprising a rigid base member, an applicator brush fixed to the base member and aligned along the longitudinal axis thereof, an overshell of compressible material disposed on the base member, the overshell providing a gripping surface on the cap.