Bottle closure

Claim 1

Selectively openable closure means, comprising a bottle including a neck having a circular axial-end opening with an outward flare at the mouth of the opening, and a cap for selectively opening and closing said opening, said neck including a radial shoulder and an annular portion axially offsetting said shoulder from said end, said cap having an outer annular wall sized to abut said shoulder and having telescoping overlap with said annular neck portion, and said annular neck portion and said wall having coacting screw-thread formations at their region of overlap; said cap being of single-piece moldeD-plastic construction and having a closed end comprising a relatively thin and stiffly compliant deformable closure section including axially downward annular flange means radially inwardly spaced from said wall, whereby the annular portion of said closure section which integrally connects said wall to the upper end of said flange means is relatively resilient within a limited range of axial displacement of said wall and flange means; the exterior of said flange means being sized and contoured (a) for interference with the flare of the neck opening in the course of said telescoping overlap and prior to cap abutment with said shoulder and (b) for continuance of such interference with increasing deformation of said flange means in the course of threaded advance of said cap into shoulder abutment, the exterior of said flange means and its axial positioning with respect to other cooperating parts of said cap and neck being such that the range of axial displacement with such interference is less than said limited range of axial displacement, said flange means including an axially extending generally cylindrical flange portion adjacent said closure section and an inwardly tapering downwardly extending flange portion integral with and depending from said cylindrical flange portion, said cylindrical portion being sized for said interference, and the flare at the mouth of the bottle opening being a generally conical counterbore at an angle substantially less than the inward taper of said flange means, whereby said limited range of axial displacement cooperates with said inward taper to provide an essentially circular line of contact between said counterbore and the intersection of said cylindrical and tapering flange portions.