JP2001520968A - Plastic screw cap for sealing bottles or the like - Google Patents

Abstract

(57) [Summary] A plastic screw cap for sealing a bottle or the like has a cylindrical screw portion having a female screw screwed into a male screw of a bottle neck and a screw cap 2. A sealing lip 24 extending diagonally outwardly from the bottom of the screw cap, with a conical sealing surface 26 which in some cases contacts a sealing lip 28 outside the end face 16 of the bottle opening. A notch 32 is provided in the conical sealing surface 26, and the notch 32 extends from a region located just outside the sealing edge 28 when the screw cap 2 is screwed into the edge 34 of the sealing lip 24. And is connected to the surrounding environment. When the bottom 6 of the screw cap 2 is curved in a dome shape, the sealing lip 24 slides along the sealing edge 28 by means of its sealing surface 26. If the pressure in the bottle and thus the curvature of the bottom 6 is sufficiently large, the notch 32 reaches the area of the sealing lip 28 and thus forms a flow path from the interior of the bottle to the surrounding environment, Leak. The characteristics of the overpressure valve formed are precisely defined and persistent.

Description

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a screw cap of the type defined in the preamble of claim 1.

A screw cap of the above-mentioned type, known from DE-A 42 26 935, has a cylindrical screw part with a female screw which is screwed into a male screw of the bottle neck. In this case, a sealing lip with a sealing surface that contacts the end face of the bottle opening extends obliquely outward from the bottom of the screw cap. Furthermore, means are provided for defining the threaded position of the screw cap. Said means has an annular end face which, when screwed in, contacts the end face of the bottle neck and thus limits subsequent screwing. The proper position of the annular end surface adjusts the force for tightening the sealing lip between the end surface of the bottle neck and the contact surface located behind the sealing lip.
Such tightening does not take place over the entire circumferential direction, but rather at least one notch is provided behind the sealing lip, whereby the sealing lip can be inserted into the recess when the pressure increases. It is curved and in this way the overpressure can escape. In the region of the notch, the sealing lip contacts only based on the inherent elasticity of the sealing lip, which is related to the preload of the sealing lip. The disadvantage of this is that, due to the partial plastic behavior of the plastic, the spring force and thus the contact force of the sealing lip diminishes over time, and therefore even if there is only a slight overpressure inside the bottle. The seal becomes airtight, which disadvantageously causes liquid to flow out of the bottle. In addition, the pressure that causes the pressure relief to prevent the rupture of the bottle cannot be precisely adjusted.

A screw cap similar to the screw cap of the type described at the outset, which is known from DE-A 38 39 351, differs from the above-mentioned screw caps in that a seal inserted instead of a sealing lip is used. The only difference is that. Thus, this known screw cap has the same disadvantages.

In the case of a plastic screw cap known from US Pat. No. 4,360,077, two annular seals extend substantially axially from the bottom of the screw cap, which seals are screwed together. Surround the edge of the opening of the bottle neck between the seals. The edges of both sealing lips are provided with ventilation slits, which are not important when the screw cap is completely screwed on, but rather, when the screw cap is unscrewed, the internal pressure from the bottle rises sharply. Instead of letting it slowly leak through the ventilation slit. This prevents explosive leaks. Therefore, no overpressure valve is required.

[0005] The object of the invention is to improve a screw cap of the type defined in the preamble of claim 1 so that the function of the overpressure valve can be achieved continuously and effectively in a simple manner. is there.

The object has been achieved by a screw cap according to the invention having the features of the characterizing part of claim 1.

[0007] The basic idea of the present invention is not to utilize the elastic deflection of the seal to form an excess pressure valve, but to use a cylindrical threaded part to operate the overpressure valve. To take advantage of the dome-shaped deformation of the bottom and adjacent edge areas caused by internal pressure. For this purpose, the sealing surface of the sealing lip is formed in a substantially conical shape so that when the screw cap is screwed on, the sealing surface contacts the sealing edge outside the end face of the bottle opening. With such a configuration and orientation of the sealing lip, when the bottom of the screw cap is bent in a dome shape in relation to the internal pressure in the bottle, the sealing lip is formed on the end face of the bottle opening based on the connection with the bottom of the screw cap. A sliding movement is performed along the outer sealing edge.

According to the invention, said sliding movement is used to form an overpressure valve, wherein at least one notch is provided in the conical sealing surface, said notch being provided with a screw. When the cap is screwed on, it extends from the area located just outside the sealing edge towards the edge of the sealing lip and is connected to the surrounding environment. If the bottom of the sealing cap is dome-shaped curved beyond a certain dimension, the notch in the conical sealing face of the sealing lip reaches the area of the sealing edge outside the end face of the bottle opening and is thus obtained. A flow passage is formed between the bottle and the surrounding environment to allow pressure to leak. Such leakage of pressure from the inside of the bottle restores the dome-like curvature at the bottom of the screw cap, which also causes the notch in the conical sealing surface to move away from the sealing edge area on the end face of the bottle opening again, The flow section, ie the overpressure valve, is closed again.

Depending on the length of the sealing lip, the angle of inclination of the contact surface and the sizing of the gap between the sealing edge and the notch, the blowing pressure can be varied widely.

When the bottle bottom is curved in a dome shape, the edge of the bottle bottom also contracts somewhat inward due to the secant-shaped shortening, wherein the edge is in the area adjacent to the cylindrical screw portion. Inward, which facilitates the dome-shaped curvature of the bottle bottom and the associated sliding movement of the sealing lip.

The cutout in the conical sealing surface is advantageously a radial passage, which forms the shortest path from the open area of the overpressure valve formed to the surrounding environment.

In an advantageous embodiment of the invention, an intermediate space is formed between the cylindrical screw part and the opening area of the bottle neck. In this way, the radial inward movement of the bottom edge of the screw cap and especially the adjacent area of the cylindrical screw part is not impeded by the peripheral surface of the bottle neck, even in the case of large deviations.

[0013] Advantageously, the sealing lip has a substantially constant thickness at least up to the notch. As a result, the contact pressure does not change below the exhaust pressure of the overpressure valve formed during the sliding movement, so that the sealing force is always of the same magnitude and consequently the airtightness below the exhaust pressure is avoided.

In an advantageous embodiment of the invention, a contact surface parallel to the conical sealing surface for the sealing lip is formed immediately after the sealing lip on the side opposite the conical sealing surface. Extending. Basically, the sealing lip is sufficiently unique to ensure that a large contact force is obtained during the sliding movement of the sealing lip in a threaded state, so that the sealing lip does not lift from the end face of the bottle opening when pressure is generated. Although they can be rigid, they require large material thicknesses and significant material costs. On the other hand, if the sealing lip is supported on the contact surface at the back, the inherent rigidity can be significantly reduced. This is because the supporting force is always large enough to prevent the lifting of the sealing lip under any pressure conditions that occur. Therefore,
Even in the case of thin sealing lips, the cutouts in the conical sealing surface can only be transferred to the area of the sealing rim outside the end face of the bottle opening, thus forming a flow path from inside the bottle to the surrounding environment. Overpressure is blown out of the bottle. Furthermore, the advantage of the above arrangement is that the opening pressure is independent of the torque for screwing the screw cap,
Therefore, there is no need for a stopper that prevents a very firm screwing. However, such a stop is advantageous in all embodiments of the invention.

[0015] In principle, one notch in the conical sealing surface is sufficient to guarantee the overpressure valve function. With only one cut-out, of course, only a small outlet cross section is obtained. For this reason, it is advantageous if a number of cutouts are provided distributed over the entire circumferential direction of the sealing lip.

In an advantageous embodiment of the invention, the screw cap has a wall in an area which is located adjacent to the sealing edge when the screw cap is screwed on, the wall being advantageously thin. Is formed by an annular notch in the bottom and is located radially inward of the sealing edge. The thin wall promotes a dome-like deformation of the bottom created by internal pressure and thus increases the sliding movement used according to the invention of the sealing lip along the outer sealing edge of the end face of the bottle opening and thus the overpressure valve Is improved.

In the sectional view of FIG. 1, a screw cap 2 having a cylindrical screw part 4 and a bottom part 6 is illustrated. The threaded portion 4 has an internal thread 8 which engages an external thread 10 of the bottle neck 12. A stopper 14 is provided on the inner side of the bottom 6, which abuts against the end face 16 of the bottle neck 12 and thus defines the screwing depth of the screw cap 2 along the bottle neck 12. A security ring 20 is connected to the screw part 4 via a material connection 18. During the first unscrewing of the screw cap 2, the material connection 18 is torn and this results in an initial opening, in which case the security ring 20 is disengaged from the screw cap 2.

A sealing lip 24 extends obliquely outward from the inner surface 22 of the bottom 6 and forms a conical sealing surface 26. The sealing surface 26 is supported by a sealing rim 28 outside the end surface 16 of the opening of the bottle neck 12 in the screwed state shown in the left half of FIG. In this case, the sealing lip 24 is clamped between the sealing edge 28 and the conical contact surface 30, the contact surface 30 being screwed into the sealing lip 24 when the sealing lip 24 contacts the sealing edge 28. Extend substantially in parallel with the sealing surface 26 of the second member.

The conical sealing surface 26 is provided with a notch 32 which, when the screw cap 2 is screwed and no excessively high overpressure is present in the bottle, allows the screw cap screw to be screwed on. It extends from a region located just outside the sealing edge 28 in the fitted state to the edge 34 of the sealing lip 24.

FIG. 2 is an enlarged view of the left half of FIG. 1 in a state where the screw cap is screwed and no excessively high internal pressure is generated. 2, the notch 32 extends from the area just outside the sealing edge 28 to the edge 34 of the sealing lip 24. This means that the sealing lip 24 is clamped between the sealing lip 28 and the contact surface 30, thus achieving the best sealing action with a high sealing force independent of the elastic properties of the sealing lip 24. are doing.

FIG. 3 corresponds to FIG. 2 but illustrates the situation when a blow-off pressure is generated at which the overpressure valve formed is opened. As can be seen from the drawing, the bottom 6
Is curved in a dome shape. This causes the edge of the threaded portion 4 and the area near the edge following the edge to curve radially inward (illustrated by arrow 36). At the same time, the base point 38 of the seal lip 24 moves slightly in the axial direction in a curved direction (illustrated by an arrow 40). Both movements in the direction of the arrows 36, 40 move the base point 38 of the sealing lip 24 in the direction of the arrow 42, thereby causing a sliding movement of the sealing lip 24 between the sealing edge 28 and the contact surface 30. As a result, the notch 32 reaches the region of the sealing lip 28 and thus forms a flow path from the interior of the bottle to the surrounding environment, through which the overpressure leaks. In this case, the female screw 8 and the male screw 10 do not form an obstacle. After decompression, the dome-shaped curvature of the bottom 6 is restored, and
6, 40, 42, and the notch 32 is again moved to the sealing edge 2.
The area 8 and thus the preformed flow path are closed.

FIG. 4 shows a variant embodiment of the embodiment of FIG. 1 in the form of FIG. Accordingly, the same or corresponding components have the same reference characters allotted. In this case, in the region radially outside the sealing edge 28 outside the end face 16 of the opening of the bottle neck 12, the bottom 6
The difference is that an annular cutout 44 is provided therein. Notch 44
It is provided on the bottom side facing the seal lip 24. The notch promotes a dome-shaped curvature of the bottom of the screw cap in the event of an internal pressure, increases the sliding movement of the sealing lip 24 and improves the function of the overpressure valve. A groove 46 provided in the inner wall of the cylindrical screw part 4 adjacent to the bottom 6 of the screw cap 2 serves the same purpose.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of a screw cap screwed into a bottle opening.

FIG. 2 is an enlarged view of the left half of FIG. 1 showing the screw cap in a closed position.

FIG. 3 shows the screw cap in the open position, corresponding to FIG. 2;

FIG. 4 is a diagram corresponding to FIG. 2 of the variant embodiment of FIG. 1;

[Explanation of symbols]

2 screw cap, 4 screw portion, 6 bottom, 8 female screw, 10 male screw, 12 bottle neck, 14 stopper, 16 end face, 18 material connection, 20 guarantee ring, 22 inner face, 24 seal lip, 26 seal face, 28 seal Rim, 30 contact surfaces, 32,44 notch, 34
Edge, 36, 40, 42 Arrow, 38 Base, 46 groove

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] April 24, 2000 (2000.4.24)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 7

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004] In the case of a plastic screw cap known from US Pat. No. 4,560,772 , two annular seals extend substantially axially from the bottom of the screw cap, and the seals are screwed together. Surround the edge of the opening of the bottle neck between the seals. The edges of both sealing lips are provided with ventilation slits, which are not important when the screw cap is completely screwed on, but rather, when the screw cap is unscrewed, the internal pressure from the bottle rises sharply. Instead of letting it slowly leak through the ventilation slit. This prevents explosive leaks. Therefore, no overpressure valve is required.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

If the bottom of the screw cap is curved in a dome shape, the edge of the screw cap also contracts somewhat inward due to the secant cut, wherein said edge is adjacent to the cylindrical screw portion. Entrained inwardly, which facilitates the dome-shaped curvature of the bottom of the screw cap and the associated sliding movement of the sealing lip.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

In an advantageous embodiment of the invention, a contact surface parallel to the conical sealing surface for the sealing lip is formed immediately after the sealing lip on the side opposite the conical sealing surface. It extends at a cone angle of less than 90 degrees . Basically, the sealing lip is sufficiently unique to ensure that a large contact force is obtained during the sliding movement of the sealing lip in a threaded state, so that the sealing lip does not lift from the end face of the bottle opening when pressure is generated. Although they can be rigid, they require large material thicknesses and significant material costs. On the other hand, if the sealing lip is supported on the contact surface at the back, the inherent rigidity can be significantly reduced. This is because the supporting force is always large enough to prevent the lifting of the sealing lip under any pressure conditions that occur. Therefore, even in the case of a thin sealing lip, only if the notch in the conical sealing surface moves into the region of the sealing edge outside the end face of the bottle opening, thus forming a flow passage from the inside of the bottle to the surrounding environment The overpressure is constantly blown from the inside of the bottle. A further advantage of this arrangement is that the opening pressure is independent of the torque for screwing the screw cap, so that no stopper is required which prevents a very tight screwing. However, such a stop is advantageous in all embodiments of the invention.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), AU, BR, CA, CN, CZ, EE, HU, JP, KR, LT, LV, MX, NO, PL, RU, SI, SK, TR, UA, USF terms (reference) 3E084 AA12 AB01 BA01 CC03 DA01 DB05 DB12 FA09 GA01 GB01 GB08 HA03 HB02 HC03 HD01 HD03 KA01 KA13 KA15 KA19

Claims (12)

[Claims] 1. A screw cap made of plastic for sealing a bottle or the like, wherein said screw cap has a cylindrical screw portion having a female screw screwed into a male screw of a bottle neck, and contacts an end face of a bottle opening. A sealing lip extending diagonally outwardly from the bottom of the screw cap having a sealing surface that seals, wherein the sealing surface (26) of the sealing lip (24) threadably engages the screw cap (2). If the sealing surface (26) is outside the sealing edge (28) of the end face (16) of the bottle opening
, And is provided with at least one notch (32) in the conical sealing surface (26), which cuts the screw cap (2). A bottle or thread, which, when screwed in, extends from a region just outside the sealing edge (28) to the edge (34) of the sealing lip (24) and is connected to the surrounding environment Plastic screw cap for sealing similar ones. 2. The screw cap according to claim 1, wherein the notch is provided as a radial passage in the conical sealing surface. 3. The screw cap according to claim 1, wherein an intermediate space is formed between the cylindrical screw part (4) and the opening area of the bottle neck (12). 4. At least one circumferential groove is arranged adjacent to the bottom (6) of the screw cap (2) to form an intermediate space in the inner wall of the cylindrical screw part (4). The screw cap according to claim 3, wherein 5. The screw cap according to claim 1, wherein the sealing lip (24) has a substantially constant thickness at least up to the notch (32). 6. A sealing lip (24) opposite the conical sealing surface (26).
6. The screw cap according to claim 5, wherein a contact surface parallel to the conical sealing surface extends for the sealing lip immediately after the sealing lip on the side of the). 7. The screw cap according to claim 6, wherein the angle of the conical contact surface (30) is less than 90 degrees. 8. The screw cap (2) is provided with a stopper (14) which abuts a part of the bottle neck for defining a screwing position of the screw cap (2). The screw cap according to any one of the preceding claims. 9. The screw cap according to claim 1, wherein the screw cap has a thin wall in an area located adjacent to the sealing edge when the screw cap is screwed. . 10. The screw cap according to claim 9, wherein the wall section is formed by an annular cutout in the bottom (6). 11. The screw cap according to claim 9, wherein the wall section is located radially outward of the sealing edge. 12. The screw cap according to claim 9, wherein the thin wall is formed by a notch (43) provided on the side of the bottom (6) facing the sealing lip (24).