US3433380A

US3433380A - Container closure

Info

Publication number: US3433380A
Application number: US677170A
Authority: US
Inventors: Claude Edward Kawchitch
Original assignee: Loy Bros Pty Ltd
Current assignee: Loy Bros Pty Ltd
Priority date: 1967-10-23
Filing date: 1967-10-23
Publication date: 1969-03-18
Anticipated expiration: 1986-03-18

Description

March 18, 1969 c. E. KAWCHITCH CONTAINER CLOSURE Filed Oct. 25, 1967 United States Patent 3,433,380 CONTAINER CLOSURE Claude Edward Kawchitch, Jolimont, Victoria, Australia, assignor to Loy Bros. Proprietary Limited, Burwood, Victoria, Australia, a corporation of Australia Filed Oct. 23, 1967, Ser. No. 677,170 US. Cl. 215-40 Int. Cl. B65d 53/02, 23/02, 41/04 2 Claims ABSTRACT OF THE DISCLOSURE A bottle closure comprising a disc with a depending peripheral skirt which screws onto the neck of a bottle, wherein the underside of the disc has a circular groove to engage the mouth rim of the bottle and is covered by a resilient sealing film.

BACKGROUND OF THE INVENTION Field pf the invention This invention relates to closures for containers and particularly to caps for bottles.

Description of prior art SUMMARY OF THE INVENTION With a view to overcoming the above mentioned disadvantages of conventional closures, the invention provides a closure for a container, comprising a disc portion, a skirt depending from the periphery of the disc portion, a circular groove in the underside of the disc portion adjacent the skirt, the groove having downwardly divergent side walls which in transverse cross section of the groove are straight and, on the inner face of the skirt, an internal thread or a plurality of projections arranged generally in the manner of an internal thread.

Preferably too, the closure further comprises a plurality of lugs spaced circumferentially of the disc portion and projecting above the upper surface of the disc portion. These lugs are preferably constituted by the upper ends of a plurality of ribs extending down the outer face of the skirt,

Preferably, a film of a resilient material overlays the side walls of the groove.

In order that the invention may be more fully explained, one embodiment thereof, and the manner of its use, will now be described in detail with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawings:

FIGURE 1 is an exploded perspective view of the neck of a bottle and a closure therefor constructed in accordance with the invention;

FIGURE 2 is an exploded vertical sectional view of the bottle neck and closure of FIGURE 1; and

FIGURE 3 is a vertical sectional view of the closure when fitted to the bottle neck.

The drawings show a closure in the form of a screw cap 11 designed to fit onto the neck of a bottle 12. Cap 11 is moulded from a resilient plastics material, for

Patented Mar. 18, 1969 example a polycarbonate, and comprises a disc portion 13 and a generally cylindrical skirt 14 depending from the periphery of the disc portion. Four external ribs 16 are spaced around the periphery of skirt 14 and project above the upper surface of disc portion 13 in the form of lugs 17. At the lower ends of ribs 16, their outer edges taper inwardly and are rounded at 18.

A circular groove 19 is formed in the underside of disc portion 13 immediately adjacent skirt 14. This groove is of inverted truncated V cross-section so that its side walls are downwardly divergent and the lower part of its outer side wall is bevelled outwardly to form a tapered lead 20'. An inverted cup-shaped recess 21 is formed centrally in the underside of disc portion 13 so that the inner side wall of groove 19 is defined by a thin flange 22 which can flex inwardly of recess 21.

The underside of cap 11 is fitted with a seal 23 which is vacuum formed from a film of an elastomer, for example the elastomer marketed under the trade name Mylar-Cryovac. Seal 23 comprises a central inverted cup-shaped portion 24 which suits the profile of recess 21 and a peripheral flange 26 which is of inverted truncated V cross-section to suit the profile of groove 19, a circular groove 27 being formed between the peripheral wall of portion 24 and the flange 26. The outer edge of flange 26 is turned outwardly at 28. As shown in FIGURE 3, cupshaped portion 24 and flange 26 of the seal fit snugly into recess 21 and groove 19 respectively of the cap. Flange 22 of the cap fits into groove 27 of the seal and the outturned edge 28 of the seal fits against the tapered lead 20 of groove 19.

The inner peripheral surface of skirt 14 of the cap is provided with an internal multi-start screw-thread 29 and in use, the cap is fitted to a bottle having a special neck 12. Neck 12 is hollow and generally cylindrical and is provided with external ribs 31 forming a multi-start external screw-thread which co-operates with the internal screw-thread 29 in the cap so that the cap can be screwed onto the neck of the bottle. At the mouth of the bottle, the inner peripheral surface of the neck diverges conically at 32 in the outward direction toward the rim. The rim 33 is radiused so that it has rounded inner and

outer edges

33A and 33B respectively. The diameter of rim 33 is equal to that of groove 19' in the underside of cap 11 and the cone angle of the diverging part 32 of the inner peripheral surface of the neck suits the slope of the inner wall of groove 19. When the cap is screwed onto the neck of the bottle, the rim of the bottle enters groove 19 in the cap. The inner wall of groove 19, which is covered by the elastomer film of seal 23, seats on the conical part 32 of the inner peripheral wall of the neck and the rounded outer edge 33B of the neck rim 33 engages the film covered outer wall of groove 19 with substantially line contact at 30 so that there is eflicient sealing of both the inner and outer sides of the rim. As the cap is tightened, thin flange 22 forming the inner wall of groove 19 flexes inwardly of recess 21 and this resilient deformation of the flange provides a radially outwardly biasing force which assists to maintain a sealing efficiency.

The extreme lower edge 35 of the cap skirt 14 has a slightly smaller underside diameter than the minor diameter of the multi-start internal screw-thread 29 (i.e., the diameter of the minor cylinder defined by the crests of the internal screw-thread) and when the cap is screwed onto the neck of the bottle, this lower edge 35 engages the neck of the bottle quite firmly with substantial line contact (except where it is relieved by the internal thread as at 36) whereas there is a slight radial clearance and a slight axial play between the internal and external screwthreads. Therefore, the cap is not centralized by the screwthreads but can rock slightly about the lower edge of its skirt so that the inner wall of groove 19 will seat correctly on the conical seating surface 32 of the bottle. The lead of the screw-

threads

29, 31, i.e., their inclination from a circumferential direction, may vary along their length in order to provide rapid closure and sealing on rotation of the cap.

The material from which cap v11 is moulded is transparent and the upper and undersides of its disc portion 13 are highly polished so that a beam of light will readily pass through them. The sealing films may then be fitted to caps of this type by means of a die having a highly reflected die surface and a light source located so as to shine a beam of light transversely through the disc portion of the cap towards the die. If for some reason the die operates without firstly receiving a film seal 23, the light beam will be reflected from the die surface back through the disc portion 13 of the cap and one or more photo-electric cells may be provided to detect reflected 'beams and cause a signal which preventsfurther operation of the die. When a sealing film is interposed between the die and the disc portion of the cap it prevents reflection of the light beam.

The above described cap and seal provides very eflicient sealing but it can be readily removed from the bottle without the use of any special tools. Ribs 16 facilitate gripping of the cap for turning movement and, if the cap is particularly tight, any convenient implement may be placed between the upwardly projecting parts 17 of the ribs and turned to release the cap. Film seal 23 can be readily renewed when the cap is to be re-used. The downwardly divergent side walls of groove 19 ensure that sealing contact is made in at least two separated locations even though the exact dimensions of the bottle and cap may vary due to manufacturing tolerances. The rim of the bottle neck need not be rounded on both its inner and outer edges as shown in the drawings. In fact with some types of bottle forming machinery it [may be easier to form the rim with a die which rounds the outer edge only and forms at the inner edge a rebate or step which extends between the outer edge and the sloping portion 32. A rim of this type will fit the cap equally as well since 40 its rounded outer edge will engage the outer wall of the groove with substantially line contact. The illustrated arrangement has been given merely by way of example and many modifications and adaptations may be made thereto. For example, the skirt of the cap could be provided with a plurality of lugs arranged in a manner of a multi-start thread in place of the continuous internal screw-thread and the gripping lugs could be readily modified. In place of inverted cup-shaped recess 21 the underside of disc portion 13 could be provided with an annular recess located immediately within flange 22 to enable the flange to flex inwardly into an annular recess. Such an annular recess could, for example, be of saw-tooth cross-section.

I claim:

1. A closure for a container comprising a disc portion, a skirt depending from the periphery of the disc portion, a circular groove in the underside of the disc portion adjacent the skirt, said groove having downwardly divergent side walls which in transverse cross-section of the groove are straight and, on the inner face of the skirt, means defining an internal screw thread, said skirt having a lower edge which is of a smaller diameter than the minor diameter of the said internal thread.

2. In combination with a closure as claimed in claim 1, a bottle having a hollow cylindrical neck portion provided with means defining an external screw thread which thread engages with the internal thread of said closure, the bottle having a mouth and an inner peripheral surface diverging conically at the mouth of the bottle in a direction outwardly of the mouth and providing a seat for the inner side wall of the groove in said closure, said lower edge of the skirt firmly engaging the neck of the bottle, there being a clearance between said internal and external screw threads so that the closure element can rock slightly about said lower edge of the skirt to insure correct seating of the inner side Wall of the groove and the conically diverging inner peripheral surface of the bottle.

References Cited UNITED STATES PATENTS 3,216,600 11/1965 Dreps 215-40 3,286,868 1 1/ 1966 Mumford 2l544 X FOREIGN PATENTS 1,049,059 8/ 195 3 France.

DONALD F. NORTON, Primary EExaminer.

US. Cl. X.-R.