AU622176B2

AU622176B2 - Closure cap made from plastic material

Info

Publication number: AU622176B2
Application number: AU34692/89A
Authority: AU
Inventors: Franz Thomas Bartl; Hans-Werner Breuer; Werner R.F. Stibal
Original assignee: Crown Cork AG
Current assignee: Crown Cork AG
Priority date: 1988-05-16
Filing date: 1989-05-11
Publication date: 1992-04-02
Anticipated expiration: 2009-05-11
Also published as: ZA893604B; AU3469289A; EP0343102B1; ATE77327T1; DE58901671D1; EP0343102A3; JPH0232955A; EP0343102A2

Abstract

A closure cap (1) made of plastic has a guarantee band (5) which engages behind corresponding projections (8) on a container neck (9). The guarantee band (5) is connected to the closure cap (1) by means of tear-off connecting tabs (4). The wall of the guarantee band runs in radially inwardly directed indentations (6), the upper limiting surfaces of which form the engagement edges (10), by means of which the guarantee band engages on the projection (8) on the container neck (9). <IMAGE>

Description

622176 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION NAME ADDRESS OF APPLICANT: Crown Cork AG Romerstrasse 83 CH-4153 Reinach SSwitzerland NAME(S) OF INVENTOR(S): Hans-Wemer BREUER Werner R.F. STIBAL Franz Thomas BARTL ADDRESS FOR SERVICE: DAVIES COLLISON Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: Closure cap made from plastic material The following statement is a full description of this invention, including the best method of performing it known to me/us:- L i I I a 'ta C( C C a *t a

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The invention relates to a closure cap made from plastic material. Such closure caps are commonly used in a number of constructions for the closure of containers, and above all for the closure of drink bottles. The security band of such closure caps is constructed so that 15 when the closure cap is placed for the first time on a container, e.g. a bottle, it comes into positive engagement with projections on the bottle in such a way that when the closure cap is unscrewed the security band is held by the projections and thereby separated from the body of the closure cap. Thus the separation or breaking away of the security band indicates whether such a container has already been opened and thus serves as a protection for the consumer.

Such closure caps can be positively connected to the neck of the container in various ways. For example, closure caps are known which snap over a bead on the neck of the container. However, the most commonly usoV are screw caps which are used above all for drink bottles. Two embodiments of such screw closures are described in DE- A1-28 19 947 and EP-AI-12 082. According to these publications, projections which can be snapped over a bead on the drink bottle when the closure cap is screwed on are provided on the inside of the security band. In DE-A1- 28 19 947 these projections are formed by inwardly directed notches cut out of the wall of the security I band. In EP-Al-12 082 projections which are directed i 2 1 radially inwards and are approximately parallelogramshaped cross-section are formed on the inside of the security band.

Such screw closures with security bands which are brought mechanically into engagement with projections or with a bead on the neck of the bottle are also known from US-A- 4 588 100, 4 595 110, 4 565 295 and 4 550 845.

In practice it has been shown that problems can occur above all when the closure caps are first screwed on on ,i C t the filling line. Such modern filling lines nowadays run at speeds of over 50,000 bottles per hour. This means c c 11 that the closure caps must be screwed onto the bottles at 15 high speed. Therefore the projections on the security band, which must be brought into engagement with their stop edges on corresponding projections on the container or bottle, should not offer very great resistance to t C expansion. However, this is problematical above all because in the known closure caps the security band C Itself is of cylindrical construction and can only be t slightly stretched. Accordingly the security band must be provided with a large internal diameter so that when the closure cap is placed on the container the projec- 2 5 tions which protrude radially inwards can bo bent out- .wards relatively easily by the projection of the mouth of the container in order to snap under the lower edge of the said projection. This necessitates projections of relatively flexible construction and a large internal diameter of the security band. On the other hand, however, this presents the danger that because of the flexit* SI 1 -3bility of the projections these latter may deform in the same way when the closure cap is unscrewed carefully and make it possible to remove the closure cap from the neck of the container without the security band being broken away from the closure cap. Thus practical problems arise from the conflicting demands of simple, easy attachment and permanent positive connection after screwing on.

The preferred object of the invention is to avoid the disadvantages of the known closure caps and in particular to provide a closure cap which on the one hand can be placed on the mouth of the container elastically and without endangering the security seal and on the other hand is permanently and positively connected to the mouth of the container after attachment.

el According to a first aspect of the present invention there is provided a plastics closure cap which is intended to be brought into positive fitting contact with the neck of a container for closure thereof, the cap having a cap base and an approximately cylindrical cap casing on the lower edge of which a security strip is fixed by means of connection elements so that it is able to be torn away, the security strip being intended to engage beneath at least one protrusion on the neck when the cap is fastened onto the container and for this purpose possesses a number of radially inwardly directed snap-in edges which reduce the free inside diameter in the area of the security strip and which are arranged at a distance from one another around the circumference of the security strip, wherein, at least in a section commencing at its free end, the wall of the security strip has radially inwardly directed indentations which deviate from the cylindrical cross sectional shape of the closure cap, which indentations are parallel to the central axis of the cap casing, whilst the upper limiting RA 4 surfaces of the indentations form the snap-in edges.

1 O153 '2ca, .3 -3a- In contrast to the prior art, the wall of the security band of an embodiment of the present invention is not of cylindrical construction but is provided with inwardly directed indentations. These indentations permit an expansion of the security band when the closure cap is first placed on the container, since the indentations merely have to be pushed radially outwards in order to increase the free internal diameter of the entire security band significantly. Furthermore, in the security band according to an embodiment of the invention no projections are needed on the inner wall of the security band, since the upper contact surfaces of the security band itself in the region of the indentations 15 form the rest edges which engage under corresponding projections on the r 1 9 :1 ~d

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1 neck of the container. By the appropriate choice of plastic material, the wall thickness of the security band and the geometric form of the indentations the closure cap can be optimised in a simple manner so that the expansion, i.e. the increase in the free internal diameter of the security band, can take place satisfactorily when the closure cap is placed on the container and when it slips over the projections on the neck of the container without the connecting elements being damaged. This can be assisted by the inclination of the security band at an S° angle towards the central axis of the closure cap in the caoo S° region of the lower edges of the indentations. An angle of approximately 45* has proved particularly advantageous J for this.

0000 oooo 0 0 015 At the same time, however, by appropriate construction of the upper contact surface of the indentations as stop 0 o edges it can be ensured that these latter snap firmly i 000 behind the projections on the neck of the container and 0 00 thus the security band holds firmly on the neck of the o9 "o container when the closure cap is opened for the first time and the connecting elements between the closure cap and the security band break reliably. Security bands ooooa which are approximately circular and corrugated in cross- 0oo25 section can be produced particularly simply and reliably.

In practice it is possible to ac:hieve a particularly good hold of the security band over the projections on the neck of the container when the security band is divided into an upper and a lower sections, the inner wall of the upper section being of approximately cylindrical coni 5 1 struction and the lower section being provided with the indentations which are directed radially inwards, and in each case an entity is formed between indentations with the upper section. The lower section can be expanded radially outwards in the manner described above and snapped over corresponding projections on the neck of the container. The upper section gives the security band additional stability and surrounds the corresponding projections on the neck of the container without coming into positive or tension.al engagement therewith.

Instead of the chosen cross-sectional shape of the security band, the indentations can also be constructed so that they have two side walls which enclose an angle.

The indentations can also consist of two inwardly directed side walls which are connected to one another by a third inner side wall. In each case the security band itself can be expanded radially outwards by stretching the indentations, which guarantees an advantageous attachment even when the closure is turned rapidly on the S' container. Depending upon the construction of the projection on the neck of the container the appropriate configuration of the indentations makes it possible to C optimise the positive fixing and thus unscrewing. Depen- 5 ding upon the shape of the projection on the neck of the Scontainer, the stop edge can be slightly inclined without thereby interfering with the positive connection of the screw cap to the container. Such an inclination of the stop edge is advantageous, above all in the production of the closure caps in an injection moulding process with tools which eject the closure cap in the axial dIrection.

i t 6 1 Particularly good results can be achieved if the stop edge is inclined at an angle of approximately 70' with respect to the longitudinal axis of the closure cap.

Embodiments of the invention are explained in greater detail below with the aid of the drawings, in which: Figure I shows a schematic representation of a closure cap in cross-section through its central axis, Sa Figure 2 shows a section through the security band of the o0 closure cap according to Figure 1 along the line I-I, o 0o °o 0 Figure 3 shows a section through a variant of a closure o .15 cap, 0 0 Figure 4 shows a partial representation of a section along the line II-II in Figure 3, 00oo a D DO Figure 5 shows a cut-away representation of a closure cap o with engaged security band on a container in section and Figures 6 to 8 show different cross-sectional shapes of C cI; security bands with the features of the invention.

11 According to Figures 1 and 2 a closure cap I has a discshaped base 2 which merges into a cylindrical casing 3.

The cap wall 3 is connected on its lower edge by means of breakable connecting pieces 4 to a security band 5. The closure cap is produced in one piece from plastic in a known manner using an injection moulding process.

'0 7 1 According to Figure 2 the security band 5 is of circular and corrugated construction. This means that in crosssection the security band is approximately circular in sections with inwardly directed indentations 6 in between. The lower edge of the security band is provided with an incline 7 which runs towards the central axis of the closure cap. As indicated by arrows in Figure 2, the security band 5 can be expanded, i.e. increased in diameter, as soon as an outwardly directed force is exerted on 10 the indentations 6. This occurs during attachment of the Z1 security band on the mouth of a container when the securr ity band with the incline 7 runs onto corresponding projections on the mouth of the container, The external configuration of a bottle with such a projection 8 is indicated schematically in Figure 3, in which the projection is at an annular distance outwards S from the neck of the bottle 9. The upper contact surfaces of the indentations 6 serve as stop edges 10 which engage under the projections 8 on the neck of the container. In this way the security band 5 is positively connected to the projections 8 on the neck of the container 9 in such a 4ay that when the closure cap is S unscrewed the security band 5 holds firm on the neck of S the container 9 so that the connecting pieces break and indicate that it is the first time the container has been opened. On the other hand, when the closure cap I is screwed onto the neck of the container 9 for the first time, the security band 5 is expanded, aided above all by the inclines 7. The stop edges 10, by contrast, are inclined at a relatively small angle, so that expansion t

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i 8 1 of the security band 5 is avoided when the closure cap is unscrewed.

Figure 3 shows a different embodiment in which the security band 5 is divided into an upper section A and a lower section B. The upper section A of the security band 5 is cylindrical, as is known in conventional security bands.

However, the lower section B is corrugated analogous with the embodiment according to Figure 2 and is provided with 10 indentations 6. The lower section B of the security band i 5 also extends cylindrically between the indentations 6; t in this region it is connected to the upper section A, ,The upper contact surfaces of the indentations 6 form stop edges 10 which engage under the projections 8 on the neck of the container 9. As in the embodiment according to Figure 1, the security band 5 can expand radially outwards in the region of the indentations when the closure cap 1 is placed on the neck of the container 9 for the first time. As can be seen from Figures 3 and 5, the angle a of the stop edge 10 is provided with a relatively gentle inclination of approximately 70' relative to the central axis of the closure cap. Thus the stop edge braces itself firmly behind the projection 8. On the i other hand, the incline 7 on the lower contact surface of the indentations 6 is constructed wi+h a relatively steep 1 angle P of 45'. The effect of this incline 7 is that the indentations 6 are curved upwards and inclined inwards, so that the expansion of the security band 5 is made easier when the closure cap is screwed onto the neck of the container 9. The angle of 45* has proved to be the optimum angle for many applications. In practice, howi l 9 Sever, it has been shown that threshold values for the angle 0 of 30* to 60' still result in good screwing on on the one hand and sufficient stability of the security band which is shortened by the incline on the other hand.

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The outer wall of the upper section A of the security band 5 runs c -nically towards the cap casing 3 so that in the cross-section according to Figure 5 it forms an acute triangle with the inner wall of the cap casing 3. Thus in the case of ejection from injection moulding tools which do not open radially, on the one hand the core of the tool which forms the inside of the cap casing 3 and the security band 5 can be withdrawn from the closure 1 so that the core projections snap over the inclined stop edges 10 and the indentations 6 expand outwards. In order to facilitate this, it is merely necessary for the outer forming part to have released the security band in the region of the section B. Because of the conical shape, the outer wall of the security band 5 in the region of the section A can also be released from the mould by ejection without an outer forming part with radial openings. Such principle of releasing from the mould is described for example in US-A-4 526 282.

Figure 6 shows an embodiment in which the security band is provided with indentations 6 which each have two side walls 6a, 6b running at an angle with respect to one another. In the embodiment according to Figure 7 the indentations 6 consist of side walls 6a, 6b of approximately equal length which enclose an obtuse angle. In both embodiments the security band 5 can be easily ex- L t* I -1- 1 panded radially outwards in the manner described in connection with Figures 1 and 3.

Figure 8 shows an embodiment in which the indentations 6 have two side walls 6a, 6b as well as a third inner side wall 6c. The side wall 6c is circular in cross-section, like the security band 5 in the outer region. This embodiment is characterised by particularly good stopping ability on the neck of the container. Nevertheless, when the closure cap is screwed on for the first time the internal diameter of the security band can be expanded by force directed radially outwards so that the side walls 6a, 6b are correspondingly bent.

In the embodiments the inclines 7 of the indentations 6, the stop edge 10 and the outer wall are shown as straight lines in cross-section in the region of the section A.

Naturally, cross-sections which are of slightly concave or convex construction curved) are also to be understood as "inclines".

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Claims

2. A closure cap according to claim i, wherein the security strip is divided into an upper and a lower I: section, the inner wall of the upper section being formed approximately cylindrically and the lower section, whilst emanating from an approximately cylindrical basic shape, being provided with inwardly directed indentations and in each case forming an entity with the upper section between two of the indentations.
3. A closure cap according to claim 1 or claim 2, wherein the security strip is, in cross section, approximately circular and corrugated.
4. A closure cap according to any one of claims 1 or 2, t 920! s spc 1S.. ii -12- characterized in that the indentations in each case possess side walls which enclose an angle. A closure cap according to any one of claims 1 or 2, characterized in that the indentations in each case possess two inwardly directed side walls which are connected together by means of a third central side wall.
6. A closure cap according to any one of the preceding claims, characterized in that the lower edge of the indentations is provided with an incline which is inclined in relation to the central axis of the closure cap. 0 a o0 7. A closure cap according to claim 6, characterized in oo that the inclines of the indentations are inclined at an angle of approximately 450 to the longitudinal axis of the closure cap. 0 0 00 8. A closure cap according to any one of the preceding oa claims characterized in that the snap-in edge is inclined a o o o towards the cap opening. 0 9 A closure cap according to claim 8, characterized in n that the snap-in edge is inclined at an angle of *°*approximately 70' towards the longitudinal axis of the closure cap. A closure cap according to any one of the preceding a claims, characterized in that the upper limiting surface of the security strip associated with the cap casing has an outward incline in the areas next to the indentations.
11. A closure cap according to any one of claims 2 to characterized in that the outside of the upper section of the security strip runs approximately conically towards the cap casing in such a way that in -13 cross section it forms an acute triangle with the inner wall of the security strip.
12. A closure cap substantially as hereinbefore described with reference to the accompanying drawings. i DATED this 16th day of January 1992 I Crown Cork AG By Its Patent Attorneys DAVIES COLLISON CAVE t c"