AU626656B2

AU626656B2 - Plastic closure and method of manufacture

Info

Publication number: AU626656B2
Application number: AU53164/90A
Authority: AU
Inventors: Frank Schellenbach
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-06-04
Filing date: 1990-04-11
Publication date: 1992-08-06
Anticipated expiration: 2008-06-03
Also published as: DE3867430D1; ATE71013T1; DE3718782A1; EP0315660A1; JPH0684028B2; AU597499B2; WO1988009715A1; JPH02500182A; AU1806488A; EP0315660B1; DE3718782C2; AU5316490A

Abstract

An injection core for two-component injection moulding, in particular of plastic stoppers for bottles and similar containers, solves the problem caused by the fact that injection cores in a single piece can only be moved with difficulty, if at all, a predetermined distance away from the first injected body, because of the design of the latter, in order to create a gap for injecting the second body. The injection core is composed of a first (1) and of a second (2) partial cores. The first partial core can be moved a predetermined distance (A, A') away from the first injected body after injecting the first substance, and the second substance can then be injected in the gap thus obtained in order to form the second injected body.

Description

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1 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATI 6 5 6 (Original) FOR OFFICE USE Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: St S4- 4 .4 Name of Applicant: Address of Applicant: FRANK SCHELLENBACH Tubinger Allee 22,, 7032 Sindelfingen, FEDERAL REPUBLIC OF GERMANY.

j I Actual Inventor(s): Address for Service: DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

SComplete specification for the invention entitled: "PLASTIC CLOSURE AND METHOD OF MANUFACTURE" The following statement is a full description of this invention, including the best method of performing it known to us 1 -2- "PLASTIC CLOSURE AND METHOD OF MANUFACTURE" The invention relates to an improved plastics closure and method of manufacturing the same.

According to one aspect of the present invention there is provided a method for injection moulding plastic closures for bottles and other containers, in moulding apparatus including a mould nest and first and second sub-cores which are displaceable with respect to the mu, ld nest; the method including the steps of: producing a first, cap-like moulding of a first substance; displacing one sub-core relative to the first moulding so as to provide an intermediate space between the first moulding and said one sub-core; injecting a second substance into said intermediate space to form a second moulding, which is connected to the first moulding to form a combined moulding; removing both sub-cores from the combined moulding; and ejecting the combined moulding from the mould nest; According to another aspect of the present invention there is provided a plastic closure for a bottle or other container which cloSure being formed-by .20 the ab.ve method and. comprising two plastic layers comt ined with one S; another by injection moulding wherein one of said layers is more rigid or less soft than the other of said layers and said more rigid or less soft of the two layers comprises a profile element for fixing the plastic closure on an opening edge of the container with which it is to be used and wherein said profile 25 element is not covered by the other one of said layers.

S" The method preferably includes the step wherein, after displacing the said one sub-core, the other sub-core is displaced by a predetermined amount Sbefore the second substance is injected.

.Preferably the second substance is softer than the first substance to form a sealing for the closure cap.

Preferably said one sub-core has a first profiled section for use in the formation of the second moulding.

911021.cmsdat.1303164.l1ct,4 N O< ~1 4 -3 Preferably said first profiled section comprises a cone which projects into the mould nest.

Preferably the first profiled section is such as to form a circular sealing bead on the second moulding.

Preferably said one sub-core comprises an inner sub-core and said other sub-core comprises an outer sub-core relative to said inner sub-core.

The profile elements may include threadings, ridges, and/or recesses.

In the particular case wherein the bottle or similar container comprises a bottle having a neck the closure may grasp the bottle neck in a cap-like manner.

Preferably the other of the two plastic layers lies between the bottle or similar container opening edge and said one layer so as to provide a seal.

Furthermore the other layer may be adapted to the form of the container opening. The other layer may comprise a circular sealing bead, and/or the other layer may comprise sub-sections of different thickness.

In one preferred form, the aforementioned one layer is weakened at a selected position with respect to material thickness. Preferably the other layer covers the weakened position of that layer.

The closure may include a cone-shaped stopper which is formed by the other layer at the weakened position in of one layer.

According to another aspect of the invention there is provided a bottle or similar container in which the container is closed airtight by a plastic closure as described above.

In another aspect of the present invention there is provided a method for closing a bottle or a similar container, wherein a plastic closure as described above is screwed onto an opening edge of the bottle or similar container. In another aspect, the plastic closure as described above is pressed onto an opening edge of the bottle or similar container.

Preferred embodiments of the invention will hereafter be described with reference to the accompanying drawings in which Figures 1 and 2 are schematic cross-sectional views of apparatus from which the closure according to the present invention can be formed.

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1 ii -4- Fig. 1 shows an axial cross-section of an injection core 10 consisting of a first sub-core 1 and a second sub-core 2. In addition, a moulding 3 is shown, i.e. a closure cap for a bottle, which has already been produced by injecting a first substance. This moulding or casting 3 comprises a threading 4, which results through a complementary recess in the second sub-core 2.

The second substance is injected after the first sub-core 1 has been displaced by a predetermined amount A with respect to the moulding 3. The distance A is for example 0.7 mm.

The division of the injection core into a first and second sub-core makes it possible for example to also provide the moulding 3 with circular ridges or vertical indentations instead of threadings or in addition to threadings, which would not allow the rotation of the injection core after completion of the moulding 3. However since the second sub-core 2 remains fixed with respect to the moulding 3 during production of the closure and only the first sub-core 1 is moved axially, the intermediate space required for injecting the second substance can be created, while ridges or the like present on the moulding 3 are not an obstacle. However, in an embodiment of the invention the outer sub-core 2 can also be displaceable relative to the inner sub-core 1 and within the first moulding 3 by an amount This can take place for example by screwing out the sub-core 2 by an amount Through the varying distances A and A' for the inner sub-core 1 and the outer sub-core 2, the possibility exists to provide the second moulding with a complicated form. For example, the sealant injected with the second substance can be thinner in the outer region as in the inner region.

25 The two sub-cores may be rotated with respect to one another by means of threadings or they can be axially shifted. The desired intermediate space for injecting the second substance is effected without this being hindered by obstacles on the moulding 3.

The inner sub-core 1 may be provided with profile elements which serve in forming the second moulding. Two examples of this are illustrated in Fig. 2.

Reference sign 5 designates a cone projecting into the mould nest, which provides a small opening in the closure cap when making the first 949* 4r 9 V 99 4 9 999 4 4* 9 9.r 9 94 9 99 91ll02 1 cmsdnt.130,531644ct,6

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moulding 3. After withdrawing the inner sub-core 1 and injection of the sealant, a region of relatively small resistance to pressure results in the middle of the closure cap. The cone 5 on the one hand consists of the second softer substance, and on the other hand, the closure cap 3 is thinner in the area around the cone as in the other regions.

Thus a safeguard against bursting can be provided in the closure cap 3 in a simple manner. With high pressure in the bottle, it cannot happen that the bottle is destroyed or the cap pops off. Moreover, the cone 5 is only pushed out of the air-tigher closure cap 3. The high pressure can then be released through the small opening, without a large amount of liquid running out. For example, for A 1 mm, this limit increases to 10 bar, while for A 2 it is about 14 bar.

A further example of a useful profile element on the second moulding is the sealing bead 6. In Fig. 2 is it provided as a circular groove 6 on the inside of the sub-core 1. The circular sealing bead 6 is provided on the axially loaded contact surface of the second moulding. This profile element serves to adapt the sealing tc the form of the bottle neck to be closed. Due to the adapted contact surface, either the allowable gas pressure can be increased or the contact pressure providing the sealing between the closure cap and the container edge can be decreased. With such profile elements, the skilled person acquires the possibility to adapt the closure cap produced by the injection core of the present invention to various requirements.

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Claims

6- THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A method for injection moulding plastic closures for bottles and other containers, in moulding apparatus including a mould nest and first and second sub-cores which are displaceable with respect to the mould nest; the method including the steps of: producing a first, cap-like moulding of a first substance; displacing one sub-core relative to the first moulding so as to provide an intermediate space between the first moulding and said one sub-core; injecting a second substance into said intermediate space to form a second moulding, which is connected to the first moulding to form a combined moulding; removing both sub-cores from the combined moulding; and ejecting the combined moulding from the mould nest; 2. A method according to claim 1 further including the step wherein, after displacing the said one sub-core, the other sub-core is displaced by a predetermined amount before the second substance is injected. 3. A method according to claim 1 or 2, wherein the second substance is softer than the first substance to form a sealing for the closure cap. 4. A method according to claim 1, 2 or 3 wherein said one sub-core has a first profiled section for use in the formation of the second inoulding. A method according to claim 4 wherein said first profiled section comprises a cone which projects into the mould nest. 6. A method according to claim 4 or claim 5 wherein the first profiled section is such as to form a circular sealing bead on the second moulding.
7. A method according to any preceding claim wherein said one sub-core comprises an inner sub-core and said other sub-core comprises an outer sub- core relative to said inner sub-core.
8. Plastic closure for a bottle or other container whieh -eeure being 4erd-mo y-the-methed-of.lai.-and comprising two plastic layers combined with one another by injection moulding wherein one of said layers is more rigid or less soft than the other of said layers and said more rigid or less soft 911021,cmsdat130,53164.1et, 4 4 4 44 .4 4 4 44*4 *1 4 C* 4 44 4 -7- of the two layers comprises a profile element for fixing the plastic closure on an opening edge of the container with which it is to be used and wherein said profile element is not covered by the other one of said layers.
9. Plastic closure according to claim 8, wherein the profile elements include threadings. Plastic closure according to claim 8 or 9 wherein the profile element includes a ridge.
11. Plastic closure according to one of claims 8 to 10, wherein the profile element includes a recess.
12. Plastic closure according to one of claims 8 to 11, wherein the bottle or similar container comprises a bottle having a neck and the closure grasps the bottle neck in a cap-like manner.
13. Plastic closure according to one of claims 8 to 12, wherein said other of the two plastic layers lies between the bottle or similar container opening edge and said one layer so as to provide a seal.
14. Plastic closure according to claim 13, wherein said other layer is adapted to the form of the container opening. Plastic closure according to any one of claims 8 to 14, wherein the other layer comprises a circular sealing bead.
16. Plastic closure according to one of claims 8 to 15 wherein the other layer comprises sub-sections of different thickness.
17. Plastic closure according to one of claims 8 to 16, wherein the said one layer is weakened at a selected position with respect to material thickness.
18. Plastic closure according to claim 17, wherein said other layer covers the weakened position of said one layer.
19. Plastic closure according to claim 17 or 18, including a cone-shaped stopper which is formed by the other layer at the weakened position in said one layer. Plastic closure substantially as hereinbefore described with reference to any one of the accompanying drawings,
21. Bottle or similar container, characterised in that the container is closed airtight by a plastic closure according to one or more of claims 8 to 911021,cmsdat.130,53164.1ct,2 -I IIIIP-il~-~_ -8-
22. Method for closing a bottle or a similar container, characterised in that a plastic closure according to one of claims 8 to 20 is screwed onto an opening edge of the bottle or similar container.
23. Method for closing a bottle or similar container, characterised in that a plastic closure according to one of claims 8 to 20 is pressed onto an opening edge of the bottle or similar container.
24. A method of injection moulding substantially as hereinbefore described with reference to any one of the accompanying drawings. 9.9. 0S** a 9 9 9 *i *9 B. .4 Dated this 21st day of October, 1991. DAVIES COLLISON Patent Attorneys for FRANK SCHELLENBACH 91102Icmsdat130,3164Jk,3Q