EP2276675B1 - Screw cap - Google Patents

Description

The invention relates to a screw cap produced by plastic injection molding with a cap base, a cap wall and a cap opening, wherein on the cap wall, an internal thread with at least one thread is formed, wherein further the thread is formed over its length with different cross-section, and, starting at the Cap opening, extending over 360 ° or more.

Such screw caps have already become known in a variety of configurations. The state of the art is approximately on the WO 01/15988 A1 , the DE 20120 965 U1 and the US 4,147,268 directed.

From the DE 8408411 U1 is known a screw cap, with continuously changing cross-section of the thread. The lower flank angle of the first cross section also includes a larger angle with a horizontal than the upper flank angle of this cross section. At one of the DE 4126418 A1 known screw cap are also given different cross sections over the length of a thread, but with equal angles of the flanks to the horizontal. The CH 226897 A has over the length of a thread different cross-sections, but also with a continuous change, further the flank angle of the second cross section to the horizontal are the same.

At such screw caps complex requirements are made. They are applied by machine to bottles, so they should be easy to handle in terms of the required forces. Often, such screw caps are also connected to a guarantee strip. In the course of unscrewing an effective separation of the guarantee band should be made. In addition, they should as possible safely on the containers such as bottles in particular can be applied. Last but not least, they should be easy to handle by the consumer.

In view of the cited prior art, an object is to provide a manufactured in plastic injection molding screw cap that meets as much as possible the complex requirements that are placed on such screw caps in machine application and in the consumer application.

The object is achieved in the subject matter of claim 1, wherein it is pointed out that the thread over a length starting corresponding to a circumferential angle of 120 ° or more, seen from the cap opening (4, 4 ') starting, a second cross-section (Q ₂ ), which is larger in area than the first cross section (Q ₁ ), which first cross section (Q ₁ ) over a length corresponding to 50 ° or more, starting at the cap opening (4,4 ') is formed, that the flanks of the second cross section with a horizontal (H) different angles (α5, α6) include that the cap opening (4,4 ') facing edge of the second cross section (Q ₂ ) (lower edge) a larger angle (α6) with the horizontal (H) includes as the flank facing the cap bottom (upper flank) and that the first cross-section (Q ₁ ) has a lower flank angle (α1) which includes a smaller angle with a horizontal than the upper flank W Inlet (α2) of the first cross section (Q ₁ ).

In this respect, it is important that initially a portion of the thread is formed, which first comes into contact with a counter thread during screwing and has the first cross section, which first cross section is smaller in area than the second cross section. This can be used, in particular, for initial screwing onto an associated bottle mouth, which is usually a standard muzzle, easy to design. Due to the fact that the second cross-section is larger in area, results in this region of the thread a very close game to the associated counter-thread of a relevant bottle mouth. This also means that practically completely the pitch of the screwing is converted into corresponding vertical movement. The latter, in turn, is favorable with regard to a defined separation of the optionally provided guarantee strip in the course of unscrewing. On the other hand, this measure also gives "grip" in the screwing motion, which is favorable, for example, with regard to a maximum torque that can be adjusted thereafter. The flanks of the second cross-section close with the horizontal different angles. They are formed asymmetrically with respect to the horizontal. So can be adjusted specifically to the vote on the mating thread. The edge facing the cap opening may be between 30 and 60 °, preferably at 50 °. In the same way, the angle of the upper flank can be between 20 and 35 °, preferably 25 °. The first cross section has a lower flank angle which includes a smaller angle with the horizontal than the upper flank angle of the first cross section. Since the screw cap when screwing with the first cross section first comes into contact with the mating thread, for example, the bottle neck, can be achieved by such a setting of a comparatively flat angle favorable tilt stability. This with nevertheless relatively easy initial unscrewing, which favors the combination of the thread in the course of unscrewing.

It is further preferred that the second cross section is given only after 90 ° -200 ° or more. Ie preferably about half a turn or a little more when screwing another cross-section (initially alone) with mating thread engaged.

The lower flank angle of the first cross section is preferably between 0 ° and 20 °, more preferably at 5 °.

It is further preferred that the first cross section extends over 50 ° to 100 ° or more. Preferably even over 120 °. The latter in any case, if, as explained below, a segmentation of the thread is provided and this peripheral portion corresponds to a segment. Should a segment be chosen to be larger, the first cross section mentioned is preferably also selected over a longer section.

In a further preferred embodiment, a third cross section is formed between the first and the second cross-section. This third cross-section preferably corresponds to the "standard" cross section customary so far for screw caps. It is preferred in this case that the third cross section has flanks with the same flank angles relative to a horizontal. The flank angle of the third cross-section is in detail preferably between 20 ° and 35 °, more preferably at 25 °.

In addition, it is preferred that the second cross section is followed by a section corresponding to the third cross section, that is to say a section corresponding to the standard cross section.

As already mentioned, it is also preferred that the thread is divided into individual segments. The interspaces thus provided are used in a known manner to allow overpressure reduction in the course of unscrewing or screwing the screw cap. A segment may preferably extend over 100 ° to 140 °, more preferably over 120 °.

It is generally understood that in such a segment, as well as in the thread as such, but there only with respect to the singular beginning and end area, in an initial or end the profile is not fully formed. The profile contour addressed here results, for example, only after 5 ° or 10 ° of the corresponding length. The length-degree numbers given in the description refer to degrees of angle with respect to a vertical center axis (state of use) of the screw cap.

It is understood from the above that a segment is formed in each case according to a first, second or third cross-section. In this case, however, it is not excluded, although preferably not provided, for a segment outside one or more of the areas defined above to have yet another cross-sectional shape.

The invention also provides a screw cap produced by a plastic injection molding method with a cap base, a cap wall and a cap opening, where n the cap wall is an internal thread with one or more threads, wherein further the screw cap is formed opening side with a tamper-evident ring, the tamper evident ring inwardly Blocking cam and has a blocking cam two circumferentially adjacent bumps or the blocking cam is formed in the circumferential direction as a blocking rib.

Also to this type of screw caps can be made to the above-mentioned prior art.

Especially in relation to the interaction of a screw cap with a thereon usually via tear-offs integrally molded originality ring arise certain requirements. On the one hand, the screw cap should nevertheless still be screwed on cheaply, but on the other hand, as clearly as possible, the separation should take place in a defined manner.

In view of this requirement, the invention has the object to form such a screw cap with tamper evident ring.

This object is achieved in a first solution in that the bumps have a different height in relation to an extension inwards or the blocking rib has over its extension at least two regions which differ in terms of their extent inwards.

The bumps or ribs are used in the course of unscrewing, at a corresponding radial projection of the associated mouth, such as a bottle to come to rest and be prevented by this concern then in a further vertical movement, whereupon the tearing takes place. On the other hand, this attack must first be overcome in the course of unscrewing.

By choosing a different degree of extent radially inward with respect to the bumps or rib, the most difficult area to overflow when screwing on, ie the bump or the area of the rib that projects furthest inward, is reduced. However, over a significant circumferential length in the course of unscrewing the, although partially reduced slightly in radial extent, stop on the counter-projection of the thread is given, which ensures a blockage of the tamper-evident ring during unscrewing and thus allows the tearing off.

It is also preferred that the cam has different distances in the starting area to a plane forming the cap opening such that one of the bumps or one of the rib sections starts closer to the opening plane than the other. The individual cams provided in the circumferential direction are thus again formed at different distances from the cap opening. This can be a stepwise offset or a skew be. This results in a favorable influence on the required torque when screwing. On the other hand, nevertheless, the desired interaction with the counter-projection when unscrewing results, since the interaction with the bottle-side projection, which leads to the tearing off of the closure ring for unscrewing the guarantee ring, with respect to all humps on the same level.

In particular, it is preferred here that the bump or rib portion of greater height begins closer to the opening plane. However, this does not mean that at the beginning of unscrewing necessarily a higher torque is required immediately. Because preferably ends the most radially inwardly projecting portions of the hump to achieve the tearing advantageous as mentioned, on a same horizontal plane, so that the first with the counter-stop when screwing coming into contact bump or rib area greater extent radially inward as it has a flatter Vorlaufkeil than the inlet region of the hump or rib portion smaller radial extent inward. Hereby compensation for the required torque is created. It can also be provided that the wedge angle is the same in each case, which is accompanied by the fact that the humps starting closer to the cap opening extend further radially inward than the other humps

Fig. 1

eine perspektivische Ansicht von unten der Schraubkappe;

Fig. 2

einen Querschnitt durch die Schraubkappe gemäß Figur 1, geschnitten entlang der Linie II-II und

Fig. 3

eine Abwinklung des Gewindeganges des Ausführungsbeispieles mit jedem Segment zugeordneter Querschnittsdarstellung.

In the following, the invention will be explained further with reference to the attached drawing, which, however, represents only one embodiment. Hereby shows:

Fig. 1

a perspective view from below of the screw cap;

Fig. 2

a cross section through the screw cap according to FIG. 1 , cut along the line II-II and

Fig. 3

an angling of the thread of the embodiment with each segment associated cross-sectional view.

Shown and described, first with reference to FIG. 1 , a screw cap 1 produced by plastic injection molding with a cap base 2 and a cap wall 3. Opposite to the cap base 2 is a cap opening 4, or, if one includes the guarantee strip, 4 ', see. FIG. 2 , educated.

On the cap wall 3, an internal thread 5 is formed, which in the embodiment has a (single) continuous, although, as described below, divided into segments, thread.

The thread is formed over its length, that is different in the embodiment depending on the segment or a number of multiple segments, with different cross-section. This is in particular on the Figures 2 and 3 to refer.

Assigned to the cap opening 4 or 4 ', the thread initially starts with a section a (see FIG. FIG. 3 ), which in the embodiment corresponds to a first segment of the thread, which region a has a first cross-section. This first cross-section Q1 is in FIG. 2 to recognize, but also in FIG. 3 shown separately again. FIG. 3 shows a development of the thread, with, for clarity, exaggerated slope or pitch (angle β). A realistic angle β for the pitch is about 2 °.

The cross sections of the thread or the segments are basically each V-shaped, with a rounded merge at the V-tip, which points radially inward. Also at the V-ends are rounded, viewed from the inside of the cap, concave curves resulting outlets of V-flanks.

The cross section Q1 has a flank angle α1 with respect to its lower flank F1, which is comparatively small. In the embodiment, the flank angle α1 is about 5 ° - 5.5 °. This comparatively small flank angle, which the flank encloses with the horizontal H, leads to an approximately horizontal course of the outer surface of the lower flank of the cross section Q1. Since this region of the thread when screwing first comes into contact with the mating thread on the bottle mouth, for example, this has a favorable effect with regard to a possible tilt-free placement of the screw cap on the thread.

The upper flank angle of the cross section Q1 includes with the horizontal one of the flank angle α1 preferably different, larger flank angle α2. In the embodiment, the flank angle α2 is about 28 ° - 29 °.

As seen in the circumferential direction of the cap wall 3, which is referred to in the present description in each case in the circumferential degree numbers, closes after about 120 °, a second section b. The second section b is given by a practically (so far for a total thread turn) usual third cross-sectional profile Q3, wherein also here with respect to a horizontal H flank angle α3 and α4 are given. The flank angles α3 and α4 are chosen differently in the exemplary embodiment in the region of the section b. You can also choose the same. They are at 20 ° - 21 ° (α3) and 35 ° - 36 ° (α4).

Subsequently, in the circumferential direction, ie after about 240 °, a thread region c follows, which is formed in the embodiment by three individual segments. In the thread area c, a second profile Q2 is formed, which is characterized by an area comparatively large profile. In the exemplary embodiment, it is larger in area than the profile Q1 and also preferably larger in area than profile Q3.

Furthermore, the profile Q2 is characterized in that two further flank angles α5 and α6 are formed, where α5 is the upper flank angle and α6 is the lower flank angle, which preferably differ from one another. The lower flank angle α6 is preferably selected larger than the upper flank angle α5. In the embodiment, α6 is about 46 ° -47 ° and α5 is about 28 ° -29 °.

In the exemplary embodiment, this region c extends over three segments, that is to say over 360 °, approximately the circumference of the cap wall, meaning just one complete revolution. Due to the large area selected cross-section and also by the aforementioned asymmetry, a good clawing with the mating thread can be achieved in this area. By this over an entire circumferential length extending portion c ensures that the entire cap when unscrewing the screw pitch also immediately implemented in tear height with respect to an example molded guarantee ring. The design is also important without the guarantee ring.

The area c is adjoined by an end area d. The end region d is formed in the embodiment by a segment, which corresponds here to a circumferential extent of about 120 °. The segment of the region d in each case has a cross section Q3, as already explained.

The angles α1 etc. were determined in such a way that straight flank areas extending in cross-section were lengthened graphically, up to an intersection point. Through this point of intersection then the horizontal H is placed.

The illustrated screw cap is further characterized by the molded-on tamper evident ring 6. The tamper-evident ring 6 is sprayed in the usual way via tear-off webs 6 of the same material with the screw cap 1.

The tamper-evident ring 6 has inwardly projecting blocking cams 7, wherein a blocking cam 7 is composed in detail of two cusps 8, 9 formed in the circumferential direction next to each other. These humps 8,9 go over a sidecut 10 into each other.

As mentioned earlier, so far as a blocking rib could be formed, but this is not shown.

The humps 8, 9 have a different height, ie a different extent radially inward in the direction of arrow P in FIG. 2 , In principle, a larger deformation is therefore required in the region of a hump 8 when screwing the screw cap over a corresponding counter-projection on the bottle or container mouth than in the hump 9 of the embodiment.

The actual extent of a bump radially inward is between 0.3-0.5 mm (smaller bump) and 0.6-0.9 mm (larger bump).

It is further provided that the bumps 8, 9 have different distances x and y to a plane forming the cap opening. The hump 8 begins On the other hand, the areas that are most radially inward are basically preferably located on a plane E, so that the further projection in the sense of a wedge formation, as shown, starting from the Plane E a smaller wedge angle or - at different extent radially inward - a smaller wedge length with respect to the hump 8 results as compared with the hump 9. Insofar a balance in terms of the necessary Aufschraubkräfte is reached.

All of the degrees and millimeter range data described above are to be understood such that the disclosure always includes all intermediate values, in particular in 1/10 ° increments or 1/100 mm increments. This also applies to an area confinement from below and / or from above.

Claims (12)

1. Screw cap (1) produced in a plastics injection-moulding process, comprising a cap base (2), a cap wall (3) and a cap opening (4, 4'), an internal thread (5), in each case comprising one thread, being formed on the cap wall (3), the thread further being formed to have a differing cross section (Q₁, Q₂, Q₃) along its length and, beginning at the cap opening, extending over 360° or more, characterised in that the thread, when viewed starting from the cap opening (4, 4'), has a second cross section (Q₂) along a length which begins corresponding to a circumferential angle of 120° or more, which cross section is greater in terms of surface area than the first cross section (Q₁), which first cross section (Q₁) is formed along a length corresponding to 50° or more beginning at the cap opening (4, 4'), in that the thread flanks of the second cross section enclose, together with a horizontal (H), different angles (α5, α6), in that the thread flank of the second cross section (Q₂) facing the cap opening (4, 4') (lower thread flank) encloses, together with the horizontal (H), a larger angle (α6) than that of the thread flank facing the cap base (upper thread flank), and in that the first cross section (Q₁) has a lower flank angle (α1) which encloses, together with a horizontal, a smaller angle than the upper flank angle (α2) of the first cross section (Q1).
2. Screw cap according to claim 1, characterised in that the second cross section (Q₃) is produced only after 90° or more.
3. Screw cap according to either of the preceding claims, characterised in that the angle (α6) of the lower thread flank of the second cross section (Q₂) is between 30° and 60° and/or in that the angle (α5) of the upper thread flank is between 20° and 35°.
4. Screw cap according to any of the preceding claims, characterised in that the lower flank angle of the first cross section (Q₁) is between 0° and 20°.
5. Screw cap according to any of the preceding claims, characterised in that the first cross section (Q₁) extends over 50° to 100° or more.
6. Screw cap according to any of the preceding claims, characterised in that a third cross section (Q₃) is formed between the first and the second cross section (Q₁, Q₂).
7. Screw cap according to claim 6, characterised in that the third cross section (Q₃) comprises thread flanks having the same flank angles (3α', α3") relative to a horizontal (H).
8. Screw cap according to any of the preceding claims, characterised in that the flank angle (α3, α4) of the third cross section (Q₃) is between 20° and 95°.
9. Screw cap according to any of the preceding claims, characterised in that a portion corresponding to the third cross section (Q₃) is connected to the second cross section (Q₂).
10. Screw cap according to any of the preceding claims, characterised in that the thread (17) is divided into individual segments.
11. Screw cap according to claim 10, characterised in that a segment extends over 100° to 140°.
12. Screw cap according to claim 11, characterised in that each segment is formed so as to correspond to a first, second or third cross section (Q₁, Q₂, Q₃).

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