Container Closure

Abstract

A closure of the type comprising an insert assembled with a cap, usually a screw-on cap, for effecting a reliable, leakproof seal between the closure and the pouring neck of a container. Included are means for rapid assembly of the parts into a commercial device ready for application to the container neck. The insert is constructed to deform when the cap is screwed down on the neck to conform the parts of the insert into leakproof relation with the neck.

Description

BACKGROUND OF THE INVENTION

It is common practice to provide a thin liner or disc of deformable material assembled with a conventional type of screw cap for containers to serve as a sealing gasket between the cap and the neck of the container. However, those known to me leave much to be desired since, in such liners, dependence is solely on squeezing of the liner between the screw cap and the top face of the container neck. In such cases, even slight loosening of the cap, as may readily occur during handling, such as the vibration of a truck, will allow evaporation or leakage.

Moreover, it has been the practice to assemble such liners with the screw cap by reliance on a peripheral fit of the disc within the interior diameter of the cap. Unless the dimensions are precisely predetermined and maintained, the disc can separate from the cap. For example, the contents of the receptacle are of an adhesive nature so that, upon unscrewing the cap the liner remains adherent to the container neck. Thus, the user is obliged to pry off the liner and re-assemble the same in its proper place within the cap.

Additionally, sealing is made dependent on a substantial squeezing force applied to the liner, which is frequently of paperboard. Successive wettings and dryings will then result in degradation of the liner and leakage.

SUMMARY OF THE INVENTION

The invention relates to an insert and cap for the purpose mentioned, characterized by features which enable the insert to "wrap around," so to speak, the upper marginal zone of the neck of the container in snug, leakproof relation therewith together with means to translate axial force applied to the insert by screwing on of the cap into radially directed force supplementing the snug relation of the cap and neck. Another feature resides in permanent retention of the cap and insert in operative relation. The configuration of the insert is such as to lend the same to molding in a resilient plastic composition, such as polyethylene, with the use of a simple mold not involving expensive movable cores.

DESCRIPTION OF THE DRAWING

FIG. 1 is a combined vertical medial cross section through the assembled cap, insert and container, a portion of the latter being in elevation;

FIG. 2 is a similar cross section of the insert in its as-molded condition;

FIG. 3 is a greatly enlarged portion of FIG. 1 to show details; and

FIG. 4 is a top plan view of the insert.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a common type of container 10 provided with a pouring neck 12. In its relation to the insert 14 the upper end of the neck has a rim 15 of substantially rectangular transverse cross section and defining, with the main portion of the neck 12, a shoulder 16. On its interior, the rim 15 has a diameter A less than the diameter B to define a flat shoulder 19 essentially perpendicular to the principal axis X--X of the bottle neck. Desirably the upper corners of the rim 15 are slightly chamfered or rounded to insure full seating of the insert.

The neck 12 is provided with a thread 21 of any desired form and pitch, single or multiple, adapted to be engaged by the cap 22 which may be of any desired exterior configuration and includes a top wall 23 and a depending skirt 24 which is internally threaded at 26 to mate with the thread 21. Around the interior of the cap 22 is a bead 31 (FIG. 3) for a purpose to appear. As shown by way of example, this bead is substantially triangular in transverse cross section having flat sides of about 90.degree. included angle, with a rounded apex and an altitutde C of 0.004 inch. However, the dimensions and shape of the bead are not critical just as long as it will admit the insert into the cap with a snap action and retain the same therein.

The insert proper 14 comprises an annular wall portion 41 continuing as an annular disc portion 42 and a downwardly extending flange portion 44. A shallow conical web 46 has its base 47 merging into the wall 41 and its apex 45 protruding slightly above the surface 42a of the disc 42. The lower edge 49 of the wall 41 has a hook-like form including beveled face 49a and a shoulder 49b. The face 49a and the chamfered edge 51 of the flange 44 enable rapid engagement of the insert with the neck of the container. It will be understood that, during this step the wall 41 will be momentarily deformed.

The flange 44 has a chamfer 53 at its outermost upper edge to enable full seating of the insert into the cap, having in mind that the adjacent re-entrant corner 54 is filleted in the customary way to reduce the incidence of fatigue cracks.

The slope 49a facilitates initial assembly of the cap and insert when the latter is thrust into the cap. If desired the upper liner corner of the rim 15 may have a similar chamfer for the same purpose.

In order to obtain reliable, tight engagement between the cap and insert, there are certain fits between the two parts pointed out as follows: dimension A, internal diameter of rim 15, (FIG. 1) is, in the example, 0.710 inch and dimension D, external diameter of wall 41 of the insert is 0.711 inch. However, when the two parts are assembled initially the apex 45 is forced downwardly by the face 50 (FIG. 1) and the resulting "toggle" action produces an outward radial displacement of the wall 41, whereby to result in snug face-to-face contact of surfaces of the rim 15 and wall 41. It will be observed that the interaction between the apex 45 and the adjacent surface 50 is controlled by the respective reactions between the two which, in turn, will depend on the characteristics of the material and the dimensions. Stated in another way, when the cap is loose on the neck the pressure of the wall 41 on the rim 15 will be a minimum and, when the cap is tightened, the web 46 is depressed to its maximum and an optimum condition of sealing obtains. However, under ordinary conditions, the surfaces 19 and 49b will afford an additional hindrance to leakage.

It is also noted that the dimension E (FIG. 2) is, in the example, 0.102 inch and the thickness F (FIG. 1) of the rim 15 is 0.090 inch whereby replacement of the insert into plug-type engagement with the neck is facilitated.

In any event, the principal sealing plane is defined by the interface between the annular disc 42 and wall 41 on the one hand and the rim 15 on the other.

To insure reliable retention of the insert in the cap there is an interference fit in terms of the dimension G (FIG. 2) of 1.014 inch for the insert and the dimension H (FIG. 1) of 1.000 inch for the cap. Further retention is obtained by the bead 31 (FIG. 3) which effectively insures that, upon unscrewing of the cap, the insert will remain lodged in the cap and not remain wedged on the neck.

Attention is directed to the thickness of the annular disc 42 which, in the example, is 0.040 inch. This is essentially equal to the thickness of a conventional bottle cap liner. Otherwise stated, the insert of the invention will not necessitate any re-design of the height of a prior conventional cap with liner.

Claims

I claim:

1. In combination with a container having a pouring neck for dispensing its fluent contents, a cap and a sealing insert located within said cap and intermediate said cap and neck, said insert being formed from a resilient but relatively shape-retaining plastic composition, said cap having a top wall and a skirt depending downwardly therefrom, said skirt having means to secure the cap on the neck and being so secured, exerting force to squeeze the insert into intimate contact with the neck, said neck having a peripheral rim at its outer extremity, said rim having a substantially rectangular, transverse cross section, a portion of said rim extending inwardly of the neck to define an overhang, said insert comprising an annular wall snugly fitting the interior wall of the rim, and a transversely positioned diaphragm spanning the annular wall on the interior thereof, an annular disc on the exterior of said annular wall overlying the outer face of the rim and a flange at the laterally exterior periphery of the annular disc, said flange snugly fitting the exterior wall of the rim, the skirt of the cap having an interior bead abutting the flange to retain the insert within the cap.

2. The combination in accordance with claim 1 wherein the diaphragm is a conical shell having its base edge merged with said annular wall and its apex above the annular disc whereby, when the closure is attached, the inner surface of the cap depresses said apex to translate the axial force exerted by the cap into radial force against the annular wall to implement the degree of sealing contact between the annular wall and rim.

3. The combination in accordance with claim 1 further characterized in that said annular wall has a peripheral portion of hook-like transverse cross section engageable under said overhang.

4. The combination in accordance with claim 1 wherein the edge of the annular wall which is disposed within the neck is chamfered to provide easy entry of the insert into the rim.