US 3741424 A
The invention contemplates a single-piece molded-plastic screw cap for secure liquid-sealing of the contents of a bottle, which may be of glass or molded-plastic construction. The seal action is established at a non-plugging interference between (a) an annular flange within the cap and (b) a flared mouth or tapered counterbore in the bottle opening. The cap arrangement is such, in relation to bottle-neck dimensions, that a strong axial force is generated by local deformation of the cap, to increasingly load the seal contact in the course of threaded advance of the cap to its fully set position; at the same time, local resilient deformation of the flange at seal contact expands the seal action from essentially a circle of contact to an annulus of contact.
Description (OCR text may contain errors)
United States Patent [1 1 Landen June 26, 1973 BOTTLE CLOSURE Primary Examiner-George E. Lowrance Assistant Examiner-Stephen Marcus 75 I t Willi d h 1 men or s James Lan Ches AttorneySandoe, Hopgood and Calimafde  Assignee: Eyelet Specialty Company, Q
Wallingford, Conn.  ABSTRACT The invention contemplates a single-piece molded-  Ellen Sept 1971 plastic screw cap for secure liquid-sealing of the con-  Ap No.; 184,074 tents of a bottle, which may be of glass or moldedplastic construction. The seal action is established at a non-plugging interference between (a) an annular [g2] :JSZII. 2l5l4iggd2lilgl flange within the cap and (b) a flared mouth or tapered i i 43 R 44 counterbore in the bottle opening. The cap arrange- 1 1e 0 earc l l ment is such, in relation to bottle-neck dimensions, that a strong axial force is generated by local deformation  References Cited of the cap, to increasingly load the seal contact in the I UNITED STATES PATENTS course of threaded advance of the cap to its fully set 3,435,975 4/1969 Weigand .."..I 215/44 position; at the same time, local resilient deformation 3,142,402 964 ox 215/43 R of the flange at seal contact expands the seal action 333L470 2/1966 Gibscm 215/43 R from essentially a circle of contact to an annulus of 3,370,732 2/1968 LaVange..... 215/43 R Contact I 3,433,380 Kawchitch 215/43 R 8 Claims, 3 Drawing Figures BOTTLE CLOSURE This invention relates to liquid-sealing bottle-closure devices, particularly those involving a threaded cap fitting over the open end of the bottle.
Bottle closures of the character indicated are commonplace, but for liquid-sealing applications, it seems to be accepted that the cap must contain a liner, be it a coating or an insert, if liquid-sealing efficiency is to be achieved. The provision of such a liner adds to the cost and inconvenience of providing and maintaining an adequate seal function.
It is, accordingly, an object of the invention to provide an improved cap and seal construction for closures of the character indicated.
It is a specific object to meet the above object utilizing a single-piece molded-plastic screw cap, having liquid-sealing properties.
It is another specific object to meet the foregoing objects with a bottle construction requiring little modification from standard designs, and no modification of existing techniques of bottle construction, be they of glass or plastic.
It is a general object to meet the above objects with a construction of elemental simplicity and low cost, and which lends itself to resealing with the same efficacy as when the bottle is initially filled and capped.
Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of the invention:
FIG. 1 is a fragmentary view in perspective, showing bottle and closure-cap elements of the invention, the cap being in a separated position;
FIG. 2 is an enlarged view in elevation, partly broken-away to a vertical section, for the separated parts of FIG. 1; and
FIG. 3 is a similar view, in elevation and partly broken-away, for a modified closure cap.
In FIGS. 1 and 2, the invention is shown in application to a removable closure cap for the open end of the neck 11 of a bottle 12, which may be constructed by. standard techniques, using conventional materials, such as glass or plastic. Bottle 12 may be designed for liquid contents, as for example a liquor bottle. The neck 11 is characterized by a radial flange 13, axially offset from the end of opening 14, by a reduced cylindrical annular portion 15 having integral threads 16. The bottle opening 14 is circular, and its mouth is outwardly flared at a counterbore 14'.
The cap 10 is a single piece of injection-molded plastic. The plastic is a deformable material having good memory, good flexural properties, a low coefficient of friction, and relative inertness to the intended liquid contents of the bottle. For consumer uses, this means inertness to household chemicals, foods and liquids including liquors. Suitable plastic materials include polypropylene and polyethylene, each of which lends itself to injection-molding of cap 10.
The cap 10 is generally cup-shaped, comprising an outer cylindrical wall portion 17 which is relatively thick (and therefore relatively rigid) and which telescopically overlaps the neck portion 15.'The outer wall portion 17 includes thread formations 18 for engagement with the neck threads 16, and the base end of wall 17 is formed with a small outward bead of flange 19 for secure limiting-abutment footing at the shoulder 13. The closed end 20 of the cap is preferably relatively thin, to permit local deformation at a downwardly converging annular taper zone 21, as will be explained in detail. As shown, a circular panel 22, within zone 21 at substantially the axial end of cap 10, forms part of the closed end 20. The closed end 20 also integrally includes downwardly projecting annular-flange means 23, in concentric and radially spaced relation within the wall portion 17.
The exterior of the flange means is sized and contoured for interference with the flare 14 in the course of the telescoping overlap of the wall 17 and neck 15 portions, the initial interference occurring well before cap abutment with shoulder 13. After initial interference, threaded advance of the closure, upon cap rotation, causes some local radial compressional deformation of the interfering part of the flange means, but the primary deformation is via the axially compliant nature of the annular connection 21 between the wall 17 and flange 23 portions.
The preferred characterizing of the exterior of flange means 23 is such as to establish a first and primarily cylindrically annular flange portion 24, rooted at the inner end of connection 21, and a second and primarily downwardly convergent annular flange portion 25, projecting toward the neck opening 14. As shown, the flange portions 24-25 are of substantially the same axial extent, and the outer surface of the tapering flange portion 25 converges from an outer radius R, to an inner radius R and at a flare angle a to the axis of the cap. This angle 0: preferably substantially. exceeds, as by a factor of two the flare angle 7 which characterizes the counterbore 14, extending'from an inner radius R to an outer radius R Preferably, also, the outer radius R of the flange means 23 is substantially the same as the outer radius R, of counterbore 14' so that, once the line 26 of intersection (between outer surfaces at 24-25) clears the outer end of the mouth (14'), all subsequent interference contact involves reaction at 26 with counterbore 14'; of course, as axial force is developed through threaded advance, the circle at 26 reduces slightly while widening to an annulus of contact with the same flared end 14' of the mouth of the bottle.
The preferred effective radial span and slope B of compliant connection 21, between inner and outer limits'R,-R is such as to provide a range D of relatively stiffly compliant axial deformation, in the direction of flattening the entire end-closure structure 21-22. This range is available to cover tolerance variations in the coacting bottle and cap formations, while at the same time assuring notable entry of the contact line 26 axially into the counterbore 14. This result is achieved by selecting the axial offset D between line 26 and the lower end of wall 17 to be less than the axial offset D, of shoulder 13 from the open end of the neck, by an amount which is in the order of magnitude of the available axially compliant accommodation D,; the legend D will be understood to suggest the location of the end plane of the neck portion 15, in the context of cap features, when the cap is secured against shoulder 13.
The threads 16-18 are shown to be of the .single pitch variety, it being sufficient for most purposes to provide between 1.5 and 2 turns of engagement. The pitch should be such as to establish initial thread engagement at 21. The use of low-friction material enables a substantial balance to become established between axial force (through axially compressed compliant reaction at 21) and radial force (through reaction to radial compression at 23). These balanced axial and radial forces both compressionally load the interference-contact region, establishing a liquid seal, without requirement for a liner or other measures.
In the modification of FIG. 3, most of the cap features are the same as previously described, and so reference numbers are repeated. FIG. 3 differs in the region of its flange means 23', in that the bore is relieved at 30, to provide more uniform and relatively thin body. It will be appreciated that the flange means 23' is more readily compressible than that 23 of FIG. 2 and that therefore in the course of establishing a closure, the annular area of sealing contact will be greater. When the closure is set, the contact deformation will further be understood to locally converge the cylindrical flange portion 24 and at the same time to locally reduce the convergence angle a of the tapering flange portion 25'. However, even it this action were to proceed to the limit of converting both flange portions 24'-25' to a single conical shape, the resulting convergence angle thereof will never reduce to less than the flare angle 7, neither will the substantial contact zone ever leave the counterbore 14'.
In one product application of the invention, for a closure 10 of overall 1.2l-inch diameter, and for a bottle opening flared to a 0.8-inch mouth (R the outer body or wall 17 is about 0.05 5-inch thick, the flange means 23 is of about 0.040 maximum thickness, and the compliant connection 21 is about 0.030-inch thick. For the more compliant flange means 23 of FIG. 3, the thinner walls at 24'-25' may be in the order of 0.0l5-inch thick. In both situations, taper at a is in the range of 15 to 25, being preferably substantially 20; taper at 'y is in the range of 7 to 15, being preferably substantially 10; and the dished taper at B is in the range of 10 to 20, being preferably It will be seen that l have described an improved closure meeting all stated'objects. Important economies, convenience and sealing efficiency are realized.
While preferred embodiments of the invention have been described in detail, it will be understood that modifications may be made without departing from the scope of the invention.
What is claimed is:
l. 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 axiallyoffsetting 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 singlepiece molded-plastic construction and having a closed 5 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 ineluding 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 displacemerit cooperates with said inward taper to provide an essentially circular line of contact between said counterbore and the inter-section of said cylindrical and tapering flange portions.
2. Closure means according to claim 1, in which the closed end of said cap extends continuously across the axial end of said cap, said flange means being an integral annular projection depending from the central region of said closed end.
3. Closure means according to claim 1, in which the annular portion of said closure section is dished inwardly in the axially downward direction, whereby the axial-force reaction to such threaded advance increases in approach to shoulder abutment.
4. Closure means according to claim 3, in which the inwardly dished slope is in the order of 15 degrees with respect to a radial plane.
5. Closure means according to claim 1, in which inward taper of said downward flange portion is in the order of to the cap axis.
6. Closure means according to claim 1, in which the axial lengths of said flange portions are substantially the same. i
7. Closure means according to claim 1, in which the flare angle is in the order of 10 to the neck axis.
8. Closure means according to claim 1, in which said flange means is of substantially uniform thickness throughout the combined extent of both said flange portions.
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