EP1943157A2

EP1943157A2 - Tamperproof cap for sealing bottles using a stretchable plastic polymer membrane on a hollow frame within a preformed rigid cover

Info

Publication number: EP1943157A2
Application number: EP06807056A
Authority: EP
Inventors: Leon Antoine Ribi
Original assignee: Ribipack SpA
Current assignee: Ribipack SpA
Priority date: 2005-10-11
Filing date: 2006-10-06
Publication date: 2008-07-16
Also published as: WO2007042484A2; US20080302755A1; ITSV20050033A1; WO2007042484A3

Abstract

A cap for hygienic sealing of bottles (1) for drinkable liquids, characterized in that it is essentially comprised of a closed bottom cylindrical, i.e. cup-shaped, aluminum sleeve (2), an insert (3), composed of a lower hollow cylindrical base (3a) and a truncated cone (3b), also having a hollow shape, and a tapered wall having two or more elongate and vertical apertures (4) formed therein, said cap is further characterized by a stretchable plastic membrane (5) which is stretched to externally cover the truncated cone-shaped section (3b) of said insert (3) as well as its top opening (3c), by an elastic plastic ring (5a) for clamping said membrane (5) against the insert (3), and also by an additional plastic structure (6), concentric with the sleeve (2) and sealingly occupies at least its closed bottom, as a seal.

Description

Tamperproof cap for sealing bottles using a stretchable plastic polymer membrane on a hollow frame within a preformed rigid cover

A variety of methods are used in prior art to seal or close bottles 1, and some of them use various doubtfully efficient tamper detection arrangements.

Furthermore, most of them are either expensive or ineffective or unsuccessful in fulfilling their intended purpose and further do not provide the desired liquid tightness to prevent the ingress of contaminants with time. For clarity, the best known and most widely used bottle closure will be only mentioned, comprising a metal or plastic capsule which is permanently secured by various arrangements to the neck of the bottle 1 and cannot be removed without being damaged, and has an upper section that can be only unscrewed after tearing a weakened annular section, e.g. having a succession of holes or cutouts. This cap or closure can only provide liquid tightness by using an elastic seal between the closed bottom of the unscrewable section and the annular edge of the opening of the bottle 1.

While these well-known methods, which are nearly equivalent in terms of liquid tightness due to their being based on the use of variously thick and shaped elastic seals, provide advantages, such as a relatively low cost and a well-established fabrication technology resulting from functional standardization of capping machines, they still do not meet all current needs, i.e., in order of importance: time-dependent and absolute impermeability to solid, liquid and gaseous contaminants, positive tamper evidence, simple application and reasonable costs.

As a rule, current closures for bottles 1 mostly provide more or less acceptable compromises, as nothing has been found heretofore to solve the problem in a general and cost-effective manner.

Low-cost requirements often influence the selection of the closure, such requirements being a function of the value of the content of the bottle 1, as well as the market size and the profit margin therefor. For example, mineral waters generally have a very large market but their profit margin, which depends on the content of the bottle 1, requires compromises to be made in the fabrication and application of closures. However, valuable and requested beverages, such as spirits or special soft drinks, exotic syrups or special alcohol or non-alcohol beverages have a smaller market but their unit profit margin is higher and justifies the use of more complex and a fortiori expensive capping which often enhances product image and adds value thereto, besides improving efficiency. Nevertheless, these special and more expensive closures do not exhibit a distinctly better efficiency as compared with market standards . Conversely, while the cap of this invention cannot be used cost-effectively for all products, it provides a good integrated solution, and reasonably integrates absolute impermeability with time to all contaminants, evidence of any tampering of the bottle 1, easy capping and a reasonable cost .

This result has been achieved in this invention by a suitable combination of the following components of the cap : a) An external cup-shaped rigid structure 2 or cover, made of aluminum or plastic and adapted to be non removably secured to the neck of the bottle 1 as described hereafter in various embodiments. b) Three further elements common and essential to all embodiments , i.e. bl) An insert 3 or frame made of an elastic or sufficiently rigid plastic polymer, i.e. having a resilient behavior in response to the deformations expected at its various parts, and composed of an hollow cylinder 3a which extends upwards (the upward direction corresponding to the upward direction of the bottle 1, i.e. of its opening) as a truncated cone 3a, also having a hollow shape, whose wall has two or more vertical elongate apertures 4 formed therein, which are symmetrical with respect to the axis of the insert 3 and open at the minimum diameter thereof, and which allow the tapered wall surfaces delimited thereby to be elastically deformed at their ends in radial directions . b) A membrane 5 of a stretchable plastic polymer (polyethylene, polyvinychlorides, ethyl vinylacetates" , etc.), which is stretched to cover the outer side of said insert 3 and also, particularly, the opening 3c of its upper section at its minimum diameter. b3) A ring 5a made of a resilient plastic material, which is designed to be fitted into an annular groove having a section complementary thereto, and formed in the cylindrical wall 3a against which the ring will compress the base of the membrane 5 stretched over the insert 3. c) Another plastic frame or structure 6, concentric with the external rigid structure 2, which, in various situations, or in the different embodiments, may wholly or partly cover the inner cylindrical side 2a as well as the closed bottom of the structure 2, or even the bottom only, thereby simply acting, in the latter case, as a seal 16.

However, an important functional element is common to all embodiments. This element is the process performed by the insert 3 with the membrane 5 stretched thereon, which consists in laying such membrane 5 on the mouth of the bottle 1 during capping, i.e. by the axial capping motion, so that it adheres thereto thanks to its shrinking ability, i.e. thanks to the vertical stretching effect on the surface of the stretchable plastic polymer in contact with the truncated cone 3b. During capping, an annular stress is generated in the structure of the membrane 5, which causes the surface of revolution of the membrane 5 to be shrunk around the mouth, thereby providing the required adhesion thereto. It shall be recalled that such adhesion is caused by the removal of the boundary air layer from the contact area between the membrane 5 and the mouth, which allows the atmospheric pressure to be transferred to the contact surface, and to generate sufficient shearing stresses to ensure adhesion. The capping process stops when the mouth, with the membrane 5 thereon, contacts the seal that may or may not be part of the structure 6 lying on the closed bottom of the rigid aluminum sleeve 2. Then, the membrane 5 elastically seals the opening of the bottle 1 and adheres thereagainst in such a manner as to ensure long-lasting impermeability of the cap to the various solid, liquid and gaseous contaminants.

A further advantage, which essentially fulfils the above mentioned requirements, is an additional tamperproofing function of said membrane 5, which will remain unbroken as bottle 1 is opened, wherefore irreversible tearing thereof is required to access the content of the bottle 1.

The most efficient embodiments of the invention will be now described, although each of them is better than the others for specific uses only. Therefore, the order of such descriptions is not related to any classification of efficiency.

Turning now to the annexed drawings :

Figs 1, Ia are different views of a first variant embodiment of this invention, showing the insert 3;

Figs. 2 and 2a are different views of a cap having a reduced structure 6 and threads 11;

Fig. 3 shows a cap having a reduced structure 6 and flaps 10;

Figs. 4 and 4a show a cap having a structure 6 with a seal 16 and threads; Fig. 5 shows a cap having a structure 6, flaps 10 and a support 7c for the insert 3;

Figs. 6 and 6a show a toothed insert 3;

Figs. 7 and 7a show an insert 3 having a wavy top;

Figs. 8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h, 8i show different caps and bottle necks;

Figs . 9 and 9a show a neck of the bottle 1 with three subnecks 7a, 7b and 7c;

Figs. 10, 11 and 12 show different sections of the invention . According to a first variant embodiment, as shown in Figs. 1 and 2, the cap includes an Al sleeve 2 having a length of 45 to 70 mm with the bottom edge 2C folded a few millimeters inwards . A structure 6 is sealingly received in said sleeve 2, and held therein by sealing deformations or protrusions or extrusions 8 of the sleeve 2, and consists of a plastic cover having threads formed in the inner wall at its bottom. Such threads 11, which may be also segmented, are molded by usual techniques. In addition to such threads 11, the structure 6 has one or two circular concentric ridges 15 on its inner bottom for better adhesion thereof, as a seal, to the mouth of the bottle 1. This structure 6 may either have its height limited to the screwing length covered by its threads or sealingly cover the whole length of the inner side of the Al sleeve 2.

In this and in all other embodiments, the caps have an insert 3 covered by a stretchable plastic polymer membrane 5 compatible with its specific organoleptic use, which is stretched over the cylindrical wall 3a, the conical wall 3b and the opening 3c at the minimum diameter thereof.

Such insert 3 holds the membrane 5 at its cylindrical bottom 3d by means of a ring 5a which compresses the membrane 5 against the outer cylindrical wall of the insert 3 on a segmented annular area whose section is complementary to the inner section of the ring 5a. The insert 3, with the membrane 5 thereon, is sealingly received within the sleeve 2 or the structure 6 within the sleeve 2. The insert 3 may lie either, in a first case of this embodiment, by its bottom 3d on the inwardly folded bottom 2c of the sleeve 2 or, in a second case, against the upper rim of an annular protuberance 7c molded on the neck of the bottle 1.

In the first case of this first embodiment of the cap, the bottle 1 has a single sub-neck or annular protuberance 7b which will vertically lock the conical end 3c of the insert 3, as set forth below.

Conversely, in the second case of this embodiment, the bottle 1 has two sub-necks or annular protrusions 7b and 7c, the conical end 3c of the insert 3 being vertically locked by 7b and the bottom 3d of the insert 3 being locked by 7c.

Still in the first case, as shown in Fig. 2, the structure 6 may have its height limited to the screwing length covered by its internal threads 11. In the second case, as shown in Fig. 5, a structure 6 will be preferably used whose length will cover the whole inner length of the Al sleeve 2.

In both cases, the internal diameter of the folded bottom 2c of the sleeve 2, on which either the bottom 2d of the insert 3 or the free bottom of the structure 6 abut, shall precisely adhere against the diameter of the neck of the bottle 1 with the cap applied thereon. This embodiment further provides a weakening arrangement 9 on the sleeve 2 along a circumference below the threads, which is designed to be torn off as the bottle 1 is opened.

The main problem of this variant is that capping occurs by screwing, when the membrane 5 is already stretched across the rim of the bottle 1, wherefore such membrane 5 is subjected to non negligible shearing stresses during screwing. This drawback is mainly solved by using thicker and more stretchable membranes 5 in combination with worms having more rounded and wider threads 11. According to a second variant embodiment, as shown in Figs. 3, 4 and 4a, the cap still includes an Al sleeve 2 typically having a length of 40 to 65 mm with the bottom edge 2c folded a few millimeters inwards. A structure 6 is sealingly received in said sleeve 2, and held therein by deformations 8 of the sleeve 2, and consists of a plastic cover sealingly introduced in the sleeve 2, and having flaps 10 at its closed bottom, i.e. radially movable portions of the cylindrical wall of the structure 6. In a first case, this mobility is obtained by forming three cuts, preferably but without limitation orthogonal to each other and continuous, which delimit a rectangle or a trapezium whose fourth side is integral with the cylindrical wall of the structure 6. Thus, these flaps are able to elastically rotate about this fourth side . All the vertical sections of these flaps 10 contain a protuberance 12 of triangular section with a 90° angle at the free apex, whereas the upper side forms an angle of about 35° with the plane perpendicular to the axis of the cap. Therefore, a horizontal crest is formed, which extends all along said flaps 10.

In a second case, the flaps 10 are integral with the cylindrical wall of the structure 6 not only along the lower side but also along the two horizontal sides, i.e. the upper and lower sides of the rectangle or trapezium, whereas the vertical sections of the flaps 10 are identical to those of the first case. From a mechanical point of view, the flaps have the elastic bending behaviour of a cantilever beam in the first case, and of a beam supported at its ends in the second case .

In both cases, these flaps are designed to snap fit into an annular extension (7b) surrounding the neck of the bottle 1 as the cap is vertically pressed against the opening for closing it .

This variant embodiment also includes an insert 3 to be sealingly introduced in the structure 6 and covered by a membrane 5, which is stretched and retained by a ring 5a against the bottom 3d of the outer cylindrical wall of the insert 3. Such insert 3 may lie by its bottom 3d on the folded bottom 2c of the sleeve 2, in which case it will be vertically retained thereon by an annular recessed step 20 (see Fig. 2) formed in the sleeve 2, whereas the structure 6 will have its height limited to the upper portion of the sleeve 2, i.e. the one comprising the flaps 10 or deformations 8 that hold the structure 6 within the sleeve 2. In the second case (see Fig. 5), in which the insert 3 lies by its bottom 3d on an annular protuberance 7 of the neck of the bottle 1, the structure 6 covers the whole length of the sleeve 2 and lies against the folded bottom 2c thereof, and holds the insert 3 therein by means of an annular groove .

In the first case a suitable bottle 1 shall have two annular protuberances 7a and 7b: the former shall be engaged by the flaps 10 and the latter shall upwardly lock the conical end 3c of the insert 3. In the second case the bottle 1 shall have three annular protuberances 7a, 7b and 7c: the first shall be engaged by the flaps 10, the second shall upwardly lock the conical end 3c of the insert 3 and the third shall act as a support for the base 3d of the insert 3.

This second embodiment also provides an annular weakening arrangement 9 on the sleeve 2.

For simplicity and cost reduction requirements, the two embodiments described above may be also provided without an Al sleeve 2.

In this case, the insert 3 will be locked within the structure 6 which will itself act as the main structure of the cap, whereas the weakening arrangement 9, already formed in the complete structure 6, will be that formed in the cylindrical wall of the external structure. In all the above variants, including the third, the insert 3 is prevented from rotating as the cap is screwed and/or unscrewed by using an insert 3 with a bottom 3d having teeth 17 whose spacings are designed to engage with particular complementary protuberances 18 of the outer wall of the neck of the bottle 1. In other particular cases, still with the purpose of preventing circular slipping, inserts 3 may have vertical raised ribs 19, which fit into corresponding grooves formed in the inner walls of structures 6 or Al sleeves 2. According to a third variant embodiment, as shown in Figs. 4 and 4a, the cap includes an Al sleeve 2 typically having a length of 40 to 65 mm with the bottom edge 2c folded a few millimeters inwards. The closed bottom of such sleeve 2 receives an elastic seal 16, possibly formed by one or more annular protuberances designed to contact the opening of the bottle 1 to optimize liquid tightness. This variant embodiment does not include a structure 6 but also includes an insert 3 to be sealingly introduced in the Al sleeve 2 and covered by a membrane 5, which is stretched and retained by a ring 5a against the bottom 3c of the outer cylindrical wall of the insert 3. This insert 3 may lie by its bottom 3d on the folded bottom 2c of the sleeve 2, as shown in Fig. 4. in which case it will be vertically retained and locked thereon by an annular recessed step 20 formed in the sleeve 2. Otherwise, the insert 3 will lie by its bottom 3d on an annular protuberance 7 of the neck of the bottle 1 and will be also vertically upwardly retained by a recessed step 20 formed in the sleeve 2. In this variant, the cap will be connected to the neck of the bottle 1 by screwing. Thus, the opening of the bottle 1 will have a screw thread and the complementary screw thread on the cap will be formed by direct embossing in the body of the Al sleeve 2. Here again the cap has an annular weakened area 9 below the screw area 1 which will be torn off upon opening. According to a feature common to all the above embodiments, the latter have been essentially provided for more efficient application of the membrane 5 by means of the insert 3. Liquid tightness and sealing of the bottle 1 along the rim of its opening is obtained thanks to the particular application of the ready-for- use stretchable plastic polymer membrane 5. Such application provides an excellent sealing effect thanks to interdependent orthogonal deformations occurring as the membrane 5 is vertically and downwardly stretched along the neck of the bottle 1. During such stretching operation the membrane 5 is vertically elongated, whereby the length of its annular transverse development tends to be reduced, i.e. its vertical elongation partly reduces its development orthogonal to such elongation. In fact, the elongation caused by a vertical pulling action creates a surface of revolution whose axis coincides with that of the insert 3. The horizontal sections of this surface are circles of variable diameters along which the membrane 5 is stressed by elastic forces, increasing with decreasing diameters, which are exerted tangentially and tend to reduce the diameter of such surface .

Once the membrane 5 has been appropriately stretched, the annular resilient stress at the mouth of the bottle 1 allows firm adhesion thereof against the outer rim of the opening. Such adhesion generates a pressure of the membrane 5 against the opening, whereby the compressed boundary air layer between the membrane 5 and the opening rim of the bottle 1 is removed. Hence, atmospheric pressure may freely act on the membrane 5 which will be compressed against the opening and will firmly resist the shearing stresses at the interface, which are obviously proportional to the contact surface and to the local coefficient of friction. These forces will elastically hold and seal the membrane 5 against the mouth. Now, in view of this situation, the insert 3 has been provided to optimize such effect .

Thanks to the insert 3, a pre-stretched, hood-like membrane 5 is applied, which has a flat surface at the top of the insert 3 and a vertical lateral surface along the conical and cylindrical walls 3a, 3b, which will be vertically stretched during capping. For this purpose, the vertical length of the membrane 5 provides considerable elongation without tearing. The action of screwing or engaging the flaps with the neck of the bottle 1, for securing the cap to the bottle 1 will keep the membrane elastically stretched across the rim of the bottle 1 to ensure sealing thereof. As the bottle 1 is opened, thereby causing simultaneous annular tearing of the weakened area 9, the opening is still closed by a portion of the membrane 5, which is stretched and fixed to the rim, thereby providing an evidence of sealing, indicating that no tampering has occurred.

KEY 1 ) Bottle;

2) Aluminum sleeve;

2a) Cylindrical section of the sleeve;

2c) Edge or bottom of the sleeve; 3) Insert;

3a) Cylindrical section of the insert;

3b) Conical section of the insert;

3c) Top opening of the insert;

3d) Bottom of the insert; 4) Aperture formed in the insert;

4a) Sectors of the insert;

5) Stretchable membrane;

5a) Ring;

5b) Housing; 6) Structure;

7a) Upper sub-neck;

7b) Intermediate sub-neck;

7c) Lower sub-neck;

8) Sealing extrusions or deformations or protrusions;

9) Weakened area in the cylindrical wall;

10) Elastic cap locking flaps;

11) Threads or worms or screw thread;

12) Teeth or ridge or protuberances of the elastic flaps 10;

14) Wavy band of the insert 3;

15) Sealing protrusions or circular concentric ridges;

16) Seal; 17) Teeth of the insert 3;

18) Protrusions or protuberances of the bottle for the teeth 17;

19) Ribs of the insert 3; 20) Step in the sleeve 2.

Claims

1) A cap for hygienic sealing of bottles (1) made of glass or another equivalent materials, for drinkable liquids, characterized in that it is essentially comprised of a closed bottom cylindrical, i.e. cup- shaped, aluminum sleeve (2) , with the edge (2c) of its open bottom side folded a few millimeters inwards to form an angle of 90°, an insert (3), preferably made of a rigid or semirigid elastic plastic material, which is received with the diameter of its external lower section adhering within said sleeve

(2) , and which is composed of a lower hollow cylindrical base (3a) possibly having different outside diameters along its external generatrices, which insert

(3) extends as a truncated cone (3b) , also having a hollow shape, tapering upwards and towards its axis of symmetry, the plane orthogonal thereto at the minimum diameter, i.e. at the distal open end, being substantially far from the closed bottom of the sleeve (2) and whose tapered wall has two or more elongate and vertical apertures

(4) formed therein, preferably equally spaced and parallel to its generatrices, whereas the sectors (4a) delimited by said apertures (4) have surfaces whose developed shape is a rectangular or trapezoidal parallelepiped, and are integral with the cylindrical base (3a) , which sectors are designed to elastically open and depart from the longitudinal axis of the cap, and also said cap is further characterized by a stretchable plastic membrane (5) which is stretched to externally cover, as a hood, the truncated cone-shaped section (3b) of said insert (3) as well as its top opening (3c) , by an elastic plastic ring (5a) or toroidal member for clamping said hood-like stretched membrane (5) against a special housing (5b) , complementary to the ring (5a) , which is formed in the outer wall of the cylindrical section (3a) of the insert (3) , and also by an additional plastic structure (6) , which is also concentric with the sleeve (2) and sealingly occupies at least its closed bottom, as a seal, and possibly even the whole or a portion of its cylindrical section (2a) , which has such a shape as to both ensure adhesion against the sleeve (2) and liquid tightness of the cap at both internal and external edges of the opening or mouth of the bottle (1) , and finally by suitable means for securing said cap to the bottle (1) , which are located at the closed bottom of the sleeve (2) above the insert (3) . 2) A cap as claimed in claim 1, characterized in that the minimum diameter (0i) of the elastic distal section formed by the sectors (4a) of the truncated cone (3b) of the insert (3) ensures elastic adhesion thereof to the neck of the bottle (1) below an annular sub-neck (7a) surrounding its expected opening and integral with the neck of the bottle (1) , whereas the bottom edge of the cylindrical section (3b) of the insert (3) wholly lies against the inwardly folded edge (2c) of the sleeve (2) . 3) A cap as claimed in claim 1, characterized in that the cylindrical section (2a) of the external aluminum sleeve (2) , without the cylindrical wall of the structure (6) , is embossed by usual techniques to form a screw thread (11) complementary to that at the opening of the bottle (1) , a seal (16) being only provided against the closed bottom of the sleeve (2) to ensure liquid tightness of the cap.

4) A cap as claimed in claim 1, characterized in that the outer aluminum cylindrical wall (2a) of the sleeve (2) has recesses (8) , formed by deformation, with or without cutouts in the skirt, extending towards the inside of the sleeve (2) , which have the function of holding the structure (6) within the sleeve (2) .

5) A cap as claimed in claim 1, characterized in that the concentric plastic structure (6) has a screw thread (11) molded and preformed therein, at the closed bottom of the sleeve (2) , which is complementary to the one on the opening of the bottle (1) .

6) A cap as claimed in claim 1, characterized in that it has a circular weakened area (9) , which is formed by contiguous perforations or equivalent material removal along a circumference that lies on a plane perpendicular to the cap axis, below the suitable means for securing the cap to the bottle (1) .

7) A cap as claimed in claim 1, characterized in that the plastic structure (6) has two or more rectangular or sub-rectangular elastic flaps which are radially movable and connected and integrated with the cylindrical section of the structure (6) along one of their upper and lower sides, which lies on a plane perpendicular to the cap axis, whereas the wall of the structure (6) at said flaps (10) has suitable apertures to allow radial motion of their free portion/s and also said elastic flaps (10) have a ridge (12) of triangular section with a rounded apex turned towards the inside of the structure (6) , whose longitudinal development lies on a plane perpendicular to the main cap axis, and whose triangular section forms an inward angle of about 90°, whereas the upper side that forms the angle of about 90° also forms an angle of about 35° with said plane perpendicular to the cap. 8) A cap as claimed in claims 1 and 7, characterized in that the flaps (10) facing their respective apertures and having said ridges (12) of triangular section are connected and integrated, by their two upper and lower sides, to the inner cylindrical wall of the structure (6) .

9) A cap as claimed in claim 1, characterized in that the lower cylindrical base of the insert (3) below the annular housing (5b) of the ring (5a) for clamping the membrane (5) has rectangular or trapezoidal teeth (17) having tapered distal ends, which are designed to engage protrusions molded on the neck of the bottle (1) , which are as wide as the teeth gaps so that said insert (3) is not allowed to rotate about the axis of the bottle (1) when it is in the inserted position.

10) A cap as claimed in claim 1, characterized in that the elastic sectors (a) delimited by wide vertical apertures (4) are interconnected at their upper or distal areas by a band (14) integral thereto, which has a non linear, preferably a wavy profile, so that its longitudinal development is longer than the circumference of the open top section of the insert (3) .

11) A neck of a bottle (1) comprising a sub-neck (7a) consisting of an annular thicker portion or protuberance of the outer wall of the neck, preferably having a constant diameter and a bottom edge section compatible with the section of the triangular protuberances of the flaps (10) , as well as a suitable height for engagement with said flaps (10) , which is located immediately below the opening rim of the bottle

(1) •

12) A neck of a bottle (1) as claimed in claim 11, comprising one or two sub-necks (7b) and (7c) , located below the sub-neck (7a) or below the threads (11) of the cap, the former (7b) being adapted to lock the conical end (3c) of the insert (3) and the latter (7c) being adapted to lock the bottom (3d) of the insert (3) .

13) A neck of a bottle (1) as claimed in claims 11 and 12, which has protrusions or protuberances (18) below the sub-neck/s (7a) and (7b) , formed by the same mold as the bottle (1) , which have the shape of a parallelepiped whose longer axis is preferably oriented vertically, with the lateral vertical walls thereof being engaged with the teeth (13) possibly located at the cylindrical base (3d) of the insert (3) with the membrane (5) thereon.