DE8710720U1 - Screw cap for containers - Google Patents

Description

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Screw cap for containers

The invention relates to a screw closure for containers according to the preamble of claim 1.

Containers, especially bottles, are fitted with screw caps with a metal closure cap. A locking ring is provided at the bottom of the closure cap, which breaks when it is unscrewed. The locking ring provides protection against accidental opening of the container and also provides a visible indication that the container has been opened for the first time, and thus serves as a guarantee of the authenticity of the container's contents.

Screw caps are known in which the 15 locking ring of the cap is formed in one piece and is made of metal. In these screw caps, the tear line is a round cut, or

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Accounts:

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.;,.·, ,Postgiro Cologne (bank code 370100 50) account no. 654-5&Ogr;&Ogr;

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All-round cut formed with one or more vertical notches that are separated from each other by webs. The lower end of the closure cap is pressed under the bead of the container and thus held to the container.

Screw caps are also known in which the closure cap is made of metal, with the locking ring being a separate plastic part, the upper ring part of which is surrounded by a flanged edge of the metal closure cap and is held in place in the closure cap, while the lower ring part, which is connected to the upper ring part by a tear line, protrudes downwards from the metal closure cap in order to grip the container bead with a lip pointing upwards and inwards (DE-GM 82 31 160). In this case, the upper ring part of the locking ring is inserted into an outwardly protruding sleeve ring of the closure cap and then the lower limiting edge of the sleeve ring is flanged over in order to hold the upper ring part in place. After inserting the locking ring, a deformation process must therefore be carried out to hold the locking ring on the closure cap. The ring sleeve has a conical shape in order to compress the upper end of the upper ring part more radially than the lower end. This gives the locking ring an internal tension so that the lower ring part snaps outwards relative to the upper ring part when it breaks off. This makes it easier to detect when the screw cap has been opened.

The known screw caps have the disadvantage that a flanging process is required to mount the locking ring on the closure cap when the locking ring is in place. Another disadvantage is that the circular blanks from which the closure caps are made by deep drawing have different dimensions than blanks for one-piece screw caps, where the locking ring is made of the metal of the closure cap. For one-piece screw caps, different blanks must therefore be punched than for two-piece screw caps, where the locking ring is made of plastic. It must be taken into account that the aluminum panels are printed before punching. Different panel sizes therefore require different printing distributions or different printing plates on a printing machine. Another problem is that with the known two-piece screw caps, the lower ring part protrudes relatively far downwards over the container bead. The two-part screw caps therefore require modifications to the container closing machines and to the feeders if both one-part and two-part screw caps are to be processed with the same closing machine.

The invention is based on the task of creating a screw cap of the type specified in the preamble of claim 1, in which no deformations have to be carried out on the cap for the assembly of the locking ring on the cap, whereby a firm, defined hold of the

Retaining ring on the cap is ensured under tension.

This object is achieved according to the invention with the features specified in the characterizing part of claim 1.

In the screw cap according to the invention, the lower part of the cuff ring is bent inwards and upwards in a V shape so that it forms a conical ring guide for the insertion of the upper ring part of the locking ring. The closure cap can be prepared in such a way that the upper ring part of the locking ring can be inserted into the closure cap by a pressing movement and snaps into place. The upper ring part is temporarily elastically deformed. As soon as the head has passed the lower limiting edge of the cuff ring, it snaps outwards over the edge of the lower limiting edge in order to be held inside the cuff ring under axial tension. As a result of the deformability of the neck of the upper ring part, the tear line, which is arranged at the lower end of the neck, is not or only slightly stressed by the deformation of the head, so that there is no danger of the lower ring part tearing off from the upper part. The securing ring is therefore attached to the closure cap by simply pressing it in, without any deformation process being necessary on the closure cap. The closure cap is preparatoryly shaped before the securing ring is inserted. Then all that remains is to roll the thread into the closure cap on a container or glass bottle.

The feature of claim 2 ensures that the head of the upper ring part is held under axial tension inside the sleeve ring. This gives the upper ring part a stable position and an exact position in the closure cap. Furthermore, the upper ring part can be pre-tensioned outwards and downwards so that the lower ring part jumps outwards when it tears off from the upper ring part along the tear line and the tear line is interrupted by webs. The protruding remnants of the lower ring part make it easier to recognize that the screw cap has been opened.

The feature of claim 3 means that the lower ring part receives a stop through the bend of the cuff ring, against which the contact surface is pressed. The part of the lower ring part that grips under the container bead presses the contact surface against the bend. This puts tension on the lower ring part and when the lower ring part tears around the circumference, it is pushed outwards more strongly in order to indicate that the container has been opened. By striking the contact surface against the bend of the cuff ring, the position of the lower ring part is also stabilized.

The features of claim 4 ensure that the circular blanks from which the closure caps are made have the same dimensions in a two-part screw cap (with a metal closure cap and a ring part made of plastic) as in a one-part screw cap.

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closure in which the metal locking ring of the closure cap is formed as a single piece. This means that the aluminum panels for both types of closure can be prefabricated in the same format sizes and also printed, with a decision only being made later as to whether these panels are to be used for a two-part or a one-part screw closure.

The screw cap according to the invention can also be designed so that the total height of the closure cap and the inserted locking ring is essentially the same as the total height of a one-piece screw cap. The same closing machines and feeders can be used for one-piece and two-piece screw caps. With two-piece screw caps, the device for flanging the edge of the closure cap around the container bead only needs to be omitted or deactivated.

In the following, an embodiment of the invention is explained in more detail with reference to the drawings.

Show it:
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Fig. 1 a longitudinal section through a screw cap during placement on the container,

Fig. 2 is a longitudinal section of the screw cap attached to the container,

Fig. 3 a representation of the stamping blank of the closure cap, partially sectioned,

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Fig. 4 the closure cap after the next operation,

Fig. 5 the closure cap after flattening the lower boundary wall,

Fig. 6 the cap after pushing up the

lower boundary wall and
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Fig. 7 the finished closure cap and the locking ring during mutual assembly.

According to Fig. 1, the closure cap 10 has a substantially cylindrical casing 11 with a flat boundary wall 12 at the upper end. The closure cap 10 contains a plastic sealing layer 13 below the boundary wall 12 and in the area of the transition between the boundary wall 12 and the casing 11. An inwardly directed bead 14 is provided on the casing 11. At the lower end of the casing 11 there is the outwardly bulging sleeve ring 15, which has a truncated cone-shaped upper boundary wall 16 that runs diagonally upwards and inwards and a lower boundary wall 17 that also runs diagonally upwards and inwards. The cone angle of the lower boundary wall 17 is smaller than that of the upper boundary wall 16. The sleeve ring 15 with the two boundary walls 16 and 17 encloses an annular space 18.

Of the container 19, which is to be closed with the closure, only the container neck 20 with the external thread 21 and the bead 22 below is shown in Figs. 1 and 2.

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of the external thread. This container 19 is a glass bottle, for example for drinks. After the closure cap with the cylindrical casing 11 is placed on the container neck 20 as shown in Fig. 1, a pressure tool presses the closure cap firmly against the container neck from above and in the process the thread 23 is rolled into the casing 11 using thread rollers, so that the thread 23 of the closure cap adapts to the thread 21 of the container neck 20.

The locking ring 24 is attached to the lower end of the closure cap 10, which is made of metal, e.g. aluminum. This locking ring is made of plastic and has an upper ring part 25 that projects into the annular space 18 and a lower ring part 26 that is connected in one piece with it and projects out from the lower end of the closure cap 10. The upper ring part 25 consists of the ring-shaped neck 27 with a relatively small wall thickness and the head 28 that is connected to it at the top and projects outwards from the neck 27 to form a step 29. The inner sides of the neck 27 and head 28 are flush with one another and form a common cylindrical inner surface. The head 28 has a bevel 30 at its upper outer end, the cone angle of which is smaller than that of the upper boundary wall 16, so that the upper end of the head 28 abuts against the inside of the boundary wall 16, while the upwardly directed edge 31 presses from below against the groove formed by the step 29.

The tear line 32 is connected to the neck 27 at the bottom. This tear line is a weakening line that runs around the entire circumference of the retaining ring 24.

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* The weakening line 32 can be interrupted at least one point by a retaining web if the lower ring part 26 is interrupted circumferentially by tear lines. When the lower

Ring part 24, the retaining webs hold the remains of the J

Lower ring part 24 to the upper ring part 25 fixed/ so {

that these remains together with the cap of the I

Container 19 must be removed. |

The tear line 32 is at the same height as |

the bend 33, where the mansard ring 15 merges into the f lower boundary wall 17. The bend 33

runs at an acute angle, preferably less than '

than 45° and in particular about 20° to the * cuff ring 15. The bend 33 is a relatively

sharp bend, as opposed to a |;

Flanged edge that has a larger radius of curvature. |

The lower ring part 26 has a cross-section |

rectangular, almost square block 34, whose |

Inner wall flush with the inner walls of neck 27 and [I

Head 28. The upper surface of the block 34 forms '*

a contact surface 35 which rests against the &rgr;

Bend 33. The outer peripheral surface of the block *

34 is approximately flush with the outer surface of the ^

Cuff ring 15. ^

From the lower area of the inner surface of the block 34, an elastic tongue 36 extends upwards and inwards. This tongue 36 slides along the outside of the bead 22 when the closure cap is pushed onto the container neck 20. As soon as the upper end of the tongue 36 has passed the bead 22, the tongue 36 lies under the

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the lower limit of the bead 22, in order to form an anchorage for the container closure on the container 19.

The locking ring 24 is attached to the closure cap 10 by inserting its head 28 into the lower end of the closure cap. The lower boundary wall 17 forms a guide bevel on which

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The upper ring part 25 of the retaining ring 24 is thereby radially deformed. Finally, the head 28 snaps over the edge 31 of the boundary wall 17, so that the upper ring part 25 can expand radially again. The distance between the shoulder 29 and the contact surface 35 is slightly smaller than the axial height of the lower boundary edge 17, so that the retaining ring is held taut by the boundary edge 17, but without the tear line 32 being subjected to excessive stress.

Between the cylindrical inner wall of the locking ring 24 and the outer wall of the bead 22 there is a gap that provides space for the tongue 36 pushed outwards by the bead 22. In contrast to the illustrated embodiment, such a gap is not required in the area of the upper ring part 25 because the tongue 36 is only located on the lower ring part and a corresponding distance of the locking ring from the container bead 22 is only required in the area of the lower ring part.

In Fig. 2, the course of the shell II ¹ is shown in dashed lines, which would result if the sleeve ring 5 together with its boundary edges 16 and 17 were not formed from the punched blank.

It can be seen that the jacket 11' would protrude beyond the lower end of the container bead 22. The course of the jacket 11' corresponds to that of a one-piece closure cap, including the locking ring. S The additional representation of the jacket 11' is intended to make it clear that the cap blank, and thus also the round plate from which the blank is made, has the same dimensions in the two-piece screw cap as the one in the two-piece screw cap.

integrally formed retaining ring. In a one-piece screw cap, the lower end of the casing 10 would be flanged around the lower end of the bead 22.

Figs. 3-7 show the individual steps of manufacturing the screw cap according to Figs. 1 and 2.

First, the punch blank 1OA shown in Fig. 3 with the jacket 11 and the limiting edge 12 is produced from a flat round blank, whereby the sleeve ring 15 with the oblique limiting edge 16 is already formed.

In a rolling process, an inward-facing bevel 40 of approximately 45° is rolled onto the sleeve ring 15 as shown in Fig. 4. Furthermore, a grip knurling 41 and an inward-facing bead 42 adjacent to it are rolled onto the casing 11.

The next process consists in flattening the bevel 40 produced according to Fig. 4 in the step shown in Fig. 5, so that an inwardly directed flange 44 is formed.

This flange 44 is bent further by approximately 60° in accordance with Fig. 6 to produce the limiting edge 17 described above, so that it points obliquely inwards and is bent by approximately 150° relative to the sleeve ring.

Fig. 7 shows the insertion of the locking ring 24 into the sleeve ring 15, whereby the locking ring is axially

1�Lgr; is pressed against the open end of the closure cap prepared in the manner described. The bevel 30 slides along the inclined boundary wall 17 until the head 25 snaps into the space 18 of the sleeve ring 15.

The screw cap prepared in this way is ready to be placed on the container neck and to have the thread 23 rolled in. As can be seen from the drawings, the limiting edge 17 is shorter than the limiting edge

16. The limiting edge 17 forms a barb that projects into the space 18 to support the retaining ring.

When the screw cap is opened, the locking ring tears along the tear line 32. If the lower ring part 26 consists of several segments, the tear lines also tear. In this case, the lower ring part 26 is connected to the upper ring part 25 via retaining webs (not shown) which ensure that each of the segments of the lower ring part remains on the upper ring part. The tearing of the lower ring part occurs when the closure cap 10 is axially rotated on the bottle screw.

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is moved, while the lower ring part 26 is anchored with the tongue 36 under the bulge 22. The tongue protrudes from the block 34 at an acute angle, whereby the spreading effect is further increased when opening.

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Claims (5)

EXPECTATIONS 1. Screw cap for container, with a metallic closure cap (10) which has an outwardly projecting cuff ring (15) with upper and lower limiting edges (16,1/) at the lower end, and a plastic retaining ring (24) which has an upper ring part (25) anchored in the sleeve ring (15) and a lower ring part connected to the upper ring part (25) via a tear or bending line (32). (26) which engages under a bead (22) of the container (19), characterized,
that the lower boundary edge (17) of the cuff ring (15) is V-shaped inwards and is bent over and that the upwardly directed edge (31) of this boundary edge (17) is in a groove (29) between a neck (27) and a head directed outwards from the neck (28) of the upper ring part (25). 2. Screw closure according to claim 1, characterized in that the head (28) of the upper ring part (25) has on the outside at the upper end an inwardly and upwardly directed bevel (30), the upper end of which presses against the oblique upper boundary edge (16) of the sleeve ring (15). 3. Screw cap according to claim 1 or 2, characterized in that the lower ring part (26) is provided with an outwardly projecting upper contact surface (35) on the lower bend (33) of the cuff ring (15). * I * Ii 4111 i Il tlAI - 15 - 4. Screw closure according to one of claims 1-3, characterized in that the jacket (11) of the closure cap (10) has such a length that without the formation of the ring collar (15) the lower edge of the jacket (H') projects downwards over the container bead (22) by approximately the amount of the bead thickness. 5. Screw closure according to one of claims 1-4, characterized in that the lower ring part (26) of the locking ring (24) has a block (34) which borders on the tear line (32) at its upper inner edge, and from whose inner wall protrudes a tongue (36) directed obliquely upwards and inwards, which engages under the container bead (22).