NZ213944A

NZ213944A - Screw-threaded closure-container assembly

Info

Publication number: NZ213944A
Application number: NZ21394485A
Authority: NZ
Inventors: E Luker
Original assignee: Sunbeam Plastics Corp
Priority date: 1984-11-05
Filing date: 1985-10-23
Publication date: 1988-02-12
Also published as: AU579679B2; FR2572714B3; GB2166422A; GB8527109D0; DE3539222A1; JPS61127451A; FR2572714A1; AU4947485A

Description

2 13944- •2 Priori Ostein , Corr.p'.eta Specification Filed: Class: Publication Dato: P.O. Jo'jrnai, No: 11 2 FEB 1988 ..........

No.: Date: NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION . . \\ *\\ 23 OCT 1985^ u NON-BACKOFF THREADED CONTAINER AND CLOSURE XI We, SUNBEAM PLASTICS CORPORATION, 3245 Kansas Road, Evansville, Indiana 47711 (U.S.A), a corporation of the State of Indiana, United States of America hereby declare the invention for which K/ we pray that a patent may ~~ i '~ be granted to JOfe/us, and the method by which it is to be performed, | to be particularly described in and by the following statement: - - 1 - (followed by Page la) :i This invention relates to threaded containers and closures, and more particularly to the type having means in addition to the screw thread engagement to hold the closure in sealing engagement with the container.

In some forms of screw type containers and closures, particularly in the so-called child proof or safety packages, it is common to provide in addition to the threads, means such as an external annular bead at the open end of the container to engage complementary means such as an annular collar on the closure cap to apply an axial force which aids in sealing the surfaces on the closure and container and to resist the tendency of the closure to loosen or turn in an opening direction. This resistance to opening or unthreading is frequently referred to as a non-backoff system, and when the container bead coacts with a flange on a closure collar the system is commonly referred to as a snap retention system which adds to the sealing force generated by the closure and container threads.

Proper operation of the snap retention system requires maintaining the dimensions of the container and closure within narrow limits. It is, therefore, a general object of this invention to provide a threaded container and closure assembly having a non-backoff feature which does not require the maintenance of close tolerances.

It is a specific object of this invention to provide a threaded closure with a plug type seal which is modified to provide a non-backoff feature without the use of an external collar and flange.

The objects of this inventions are accomplished by providing a container with a threaded neck forming an opening with an annular bead formed on the inside of the neck adjacent to its open end. A cup-shaped cap having - ) a - internal threads to engage the threads on the neck of the container is provided with a plug seal member which has a downwardly diverging annular flange. This flange; provides a radially outwardly facing conical friction surface for engagement with the annular bead on the container. The lower end of the flange is provided with a downwardly converging cam surface which coacts with the bead for guiding the plug into the container as the cap is screwed onto the container. Tne conical friction surface created by the depending flange of the plug seal is disposed at an angle of 7° to 30° to the longitidunal axis of the container, preferably at 15°, to optimize the generation of a downward sealing force as the cap is screwed onto the container.

The end of the flange is directed inwardly at a converging angle of 10° to 45° with the longitudinal axis of the container, preferably at 30° to provide the cam surface with a low friction guide surface for the container bead. The container bead can have a full radius so as to form an inwardly projecting toroidal surface for engagement with the flange surfaces without the interference that might be caused by contact of a portion of the flange with the inside wall of the container. Instead of a full radius bead, an upwardly facing quarter circle bead can be employed in conjunction with a lower relief surface extending away from the radius towards the inside wall of the container at an angle of 10° to 60° to the longitudinal axis of the container, preferably at an angle of 30°, to avoid such interference of the flange with the inside diameter of the container.

The presently preferred embodiment of the invention is illustrated in the accompanying drawing in which: FIG. 1 is an elevational view in cross-section of the container and closure embodying the invention in a position in which the cap is being screwed onto the container before contact is made between the plug seal flange and the internal container bead; FIG. 2 is a fragmentary cross-sectional view similar to FIG. 1 showing the closure cap and the container in its fully sealed position; and FIG. 3 is a fragmentary cross-sectional view similar to FIG. 1 showing an alternative embodiment wherein a full radius bead is employed on the inside of the container neck.

The container and closure asseinbly is shown generally at 10 and includes a container 12 and a closure cap 14.

The container 12 can be in the form of a bottle having a neck 16 formed with external threads 18. The container 12 has formed on the inside of neck 16 an annular bead 20 which is adjacent to the open end of the container.

Bead 20 may take the form of an upwardly facing quarter circle radius 22 as shown in FIGS. 1 and 2, or a full radius so as to form an inwaidly projecting toroidal surface 24 as shown in FIG. 3. Cap 14 has internal threads 26 to mate with complementary container threads 18 and a downwardly depending plug seal 2 8 having an annular flange 30 which diverges as it extends away from the top surface of the cap to form an outer conical friction surface 32 for sealing engagement with annular bead 20. The lower end of the flange 30 is formed with a downwardly converging cam surface 34 for coaction with bead 20 in guiding the plug into the container as the cap is screwed onto the container. The conical friction surface 32 created by the depending flange 30 of plug seal 28 is disposed at an angle A of 7° to 30° to the longitudinal axis of the container, preferably at 15p, to optimize the creation of a downward sealing force against bead 20 as the cap 14 is screwed onto container 12 which acts to resist the tendency of the closure to loosen or turn in an opening direction, giving the closure and container the desired non-backoff feature. The lower cam surface 34 on flange 30 is formed with a downwardly converging angle B of 10° to 45° with the longitudinal axis of the container to provide a guiding surface with a minumum amount of frictional resistance upon which bead 20 will ride as the cap is tightened onto the container. Once the bead has passed the can surface 34 to engage with the conical friction surface 32, it is important that the flange is not distorted away from the bead by contact with container neck 16. In the embodiment shown in FIGS. 1 and 2, bead 20 is formed as an upwardly facing quarter circle radius for sealing engagement with conical surface 32 and a relief surface 36 extends downwardly towards the inside of container neck 16. This relief surface is preferably at an angle C of 10° to 60° with the longitudinal axis of the container (preferably 30°), in order to provide full sealing contact of the bead with the conical surface while avoiding any further contact of the flange with the inside container surface. 7m alternative configuration for bead 20 is shown in FIG. 3 wherein the bead is formed with a full radius so as to provide an inwardly projecting toroidal surface for sealing against the conical friction surface without any other part of the flange contacting the inside of the neck.

Claims

— J 2 X OUHUi-.iU l - 13 f J WHAT fy'V-JG. CUIM IS: O

1. A. container and closure assembly comprising, in combination; a container having an externally threaded cylindrical neck portion forming an opening, and an annular bead on 5 the inside of said neck adjacent the end thereof; a cup-shaped cap member having internal threads to engage with the threads on the neck of said container 5 and a plug seal member having an annular flange diverging downwardly at an anqle of 7° to 30° to the longitudinal axis of the container with a radially 10 outward facing conical friction surface for engagement with said annular bead, the lower end of said flange having a cam surface converging downwardly at an angle of 10° to 45° with the longitudinal axis of said container for coaction with said bead for guiding said plug into sai'd container as the cap is screwed onto said container, the coaction of said bead with said conical 15 friction surface exerting a force to pull said cap down on said container in a sealed position. 20

** 2. The container and closure assembly of Claim 1 wherein said conical friction surface makes an angle of substantially 15° to the longitudinal axis of said container 25 and said cam surface makes an angle of substantially 30° with said longitudinal axis of said container.

3. The container and closure assembly of Claim 1 wherein said bead has a full radius so as to form an inwardly projecting toroidal surface for sealing against said conical friction surface.

4. The container and closure assembly of Claim 1 wherein said bead lias an upwardly facing quarter circle radius with a lower relief surface extending away from said radius toward said inside wall.

5. The container and closure assembly of Claim 4 wherein said lower relief surface extends away from said radius toward said inside wall at an angle of 10° to 60° to the longitudinal axis of said container.

6. The container and closure assembly of Claim 5 wherein said relief surface angle is substantially 30°.

7. The container and cLosure assembly of Claim 1 wherein said bead has a full radius so as to form an inwardly projecting toroidal surface for sealing against said conical friction surface.

8. The container and closure assembly of Claim 1 wherein said bead has an upwardly facing quarter circle radius with a lower relief surface extending away from said radius toward said inside wall at an angle of 10° to 60° to the longitudinal axis of said container.

9. The container and closure assembly of Claim g wherein said relief surface angle is substantially 30°.

10. The container and closure assembly of Claim 8 wherein said conical friction surface maker, an angle of substantially 15° to the longitudinal axis of said container, said cam surface makes an angle of substantially 30° with the longitudinal axis of said container, and said lower relief surface extends away from said radius toward said inside_ * r f'k wall at an angle of substantially: 30° to the longitudinal ara&g u °' of said container. I /A- V,

11. A container and closure assembly substantially as herein described with reference to any one embodiment shown in the acccnpanying drawings. vro th1s /;/" day qv- Oec€rnb^r 19 TA^iv a go:-J //*' * %C -V 1/ e rv v