Screw Cap for Large Containers

Abstract

A plastic screw cap (100) for large containers, comprises a cylindrical outer jacket (1) having a first internal thread (2) of larger diameter and a head plate (3), which at least partially closes the outer jacket (1) at an axial end, wherein the head plate has an opening (4), which accommodates a removal sleeve (20) having an approximately cylindrical inner jacket having a second internal thread (12) of smaller diameter, which inner jacket protrudes into the interior of the outer jacket, wherein the head plate (3) and the removal sleeve (20) are integrally joined to each other. In order to provide caps of the same functionality that can be produced more simply, the outer jacket (1), according to the invention, together with the head plate (3) on the one hand and the removal sleeve (20) together with the internal thread (2) on the other hand are produced separately from each other by injection molding and are joined to each other fixedly and tightly by welding in order to form the complete screw cap (100).

Claims

1. A screw closure (100) of plastic for large containers, comprising a cylindrical outer shell (1) having a first female thread (2) of larger diameter and a head plate (3) which at least partially closes the outer shell (1) at an axial end, wherein the head plate (3) has an opening (4) which in turn accommodates a removal sleeve (20) having an approximately cylindrical inner shell (11) which projects into the interior of the outer shell and has a second female thread (12) of smaller diameter, wherein the head plate (3) and the removal sleeve (20) are integrally connected together, characterised in that the outer shell (1) with head plate (3) on the one hand and the removal sleeve (20) with female thread (2) on the other hand are produced separately from each other by injection moulding and are fixedly and tightly connected together by welding or gluing to form the complete screw closure (100).

2. A screw closure (100) according to claim 1 characterised in that the removal sleeve (20) at its outer end has a flange edge (16) surrounding the sleeve opening (14) for connection to an edge surface (5) surrounding the opening (4) of the head plate (3).

3. A screw closure (100) according to claim 2 characterised in that prior to the welding operation provided on the side of the flange edge (16) that is towards the head plate (3) and/or on the side towards the flange edge (16) of the edge surface (5) surrounding the opening (4) of the head plate (3), are energy direction means (17) which in the welding operation using ultrasound quickly melt and provide a desired fixed and sealed connection to the respectively opposite surface.

4. A screw closure (100) according to claim 1 characterised in that the energy direction means (17) provided on the flange edge (16) or the edge surface (5) are projections which extend axially from the respective surface and narrow away from the surface.

5. A screw closure (100) according to claim 4 characterised in that the energy direction means are ribs (17) of triangular cross-section which extend radially and/or in the peripheral direction.

6. A screw closure (100) according to claim 1 characterised in that the head plate (3) on its outside has an annular recess (6) which surrounds the opening (4) and is set back axially and the dimensions of which are designed for flush accommodation of a flange edge (16) of the removal sleeve (20).

7. A screw closure (100) according to claim 1 characterised in that at its inner end the removal sleeve (20) has a sealing disc (13) which can be at least partially separated out.

8. A screw closure (100) according to claim 7 characterised in that the sealing disc (13) has a peripherally extending weakening line near its outer edge.

9. A screw closure (100) according to claim 8 characterised in that provided in a limited peripheral angular region on the sealing disc (13) and near the peripherally extending weakening line (18) is an axially outwardly projecting local raised portion (15) for engagement with a removal spout (30) which is to be screwed into the female thread (2).

10. A screw closure (100) according to claim 8 characterised in that the weakening line (18), is such that it passes a UN drop test of a filled container of a mass of up to 25 kg from a height of 1 m without tearing open.

11. A screw closure (100) according to claim 1 characterised in that the female thread (2) on the removal sleeve (20) has a pitch of at most 3 mm, preferably at most 2 mm over 360.

12. A first part (10) of a closure (100) comprising two assembled, sealingly connected parts (10, 20), wherein the first part (10) has a cylindrical outer shell (1) having a first female thread of a first diameter and a head plate (3) closing the outer shell at an axial end, wherein the head plate (3) has an opening (4), characterised in that an annular region is of an axially set-back configuration around the opening.

13. A second part (20) of a closure (100) comprising two assembled, sealingly connected parts (10, 20), wherein the second part (20) in the form of a sleeve closed at one end by a bottom, a cylindrical shell with a female thread of a second diameter and a flange edge (16) surrounding an axial opening in the sleeve, wherein the bottom has a peripherally extending weakening line (18) near its outer periphery and on one side has a raised portion (15) facing towards the open side and near the weakening line, which axially projects with respect to the other regions near the weakening line (18), characterized in that at its underside the flange edge (16) has energy direction means (17) provided for welding the flange edge (16) to an oppositely disposed surface of a first closure part (10).

14. A process for producing a closure (100) and closure parts (10, 20) according to claim 1 characterised in that in a first step a first larger screw cap is produced by injection moulding, which has a cylindrical cap shell having a female thread and a head plate (3) which in turn has an opening (4), wherein in a second separate step a removal sleeve (20) is produced, which has at least one cylindrical inner shell having a second female thread, wherein the removal sleeve in comparison with the opening (4) of the head plate (3) is of such a size that in that way it is oriented and can be oriented in peripheral contact therewith, and the head plate (3) is welded to the removal sleeve (20).

15. A process according to claim 14 characterised in that the removal sleeve (20) and the head plate (3) are welded together by ultrasound friction welding.

16. A process according to claim 14 for producing a closure (100) characterised in that on the outside or inside a flange edge (16) bears against a region of the head plate (3) surrounding an opening (4), wherein in a third step the flange edge (16) is welded to the region surrounding the opening (4) in the head plate (3).

Description

[0035] Further advantages, features and possible uses will be apparent from the following description of preferred embodiments and the accompanying Figures in which:

[0036] FIG. 1 shows a perspective outside view of the closure consisting of two parts,

[0037] FIG. 2a shows a sectional view containing the axis of the closure through the closure of FIG. 1,

[0038] FIG. 2b shows a view from above or from the outside on to the closure of FIG. 1 and FIG. 2a,

[0039] FIG. 3 shows a sectional view through the two first and the second closure parts in the mutually separated state,

[0040] FIG. 4a shows a view from above on to the second closure part,

[0041] FIG. 4b shows a view from below on to the second closure part,

[0042] FIG. 5 shows a perspective view of the closure of FIG. 1 with a screwed-in removal spout, and

[0043] FIG. 6 shows a sectional view through the closure of FIG. 1 with the removal spout screwed in.

[0044] FIG. 1 shows a perspective view inclinedly from above and from the outside of the closure 100 which is welded together from two parts. The terms above and outside refer in the present description to the view of a closure which is screwed on to the neck of an upright container. If in use the container is inverted for the removal of drinking water or another liquid the closure is correspondingly disposed at the underside of the container.

[0045] The description hereinafter of an embodiment by way of example of the invention refers firstly to FIGS. 1 to 4.

[0046] The closure has an outer shell 1, at the lower edge of which is disposed an anti-tamper strip 2 which is connected to the outer shell 1 by easily frangible bridges (not shown). The outer shell 1 has a series of ribs 21, 21a which are intended to make it easier to handle the closure, in particular when tightening the closure on a container neck and slackening it therefrom.

[0047] The second closure part 20 has a peripherally extending flange edge 16 which is accommodated flush in an annular recess 6 in the head plate 3. The second closure part 20 forms a removal sleeve and has an inner shell 11 having a central opening 14 therethrough and a female thread 12. The opening 14 is closed by a sealing disc 13 at the lower end of the removal sleeve 20.

[0048] The two closure parts 10 and 20 can be seen in section in FIG. 2a. The outer first closure part 10, as already mentioned, has an outer shell 1 on which a female thread 2 is provided. In addition extending approximately perpendicularly to the shell 1 at the upper end thereof is a transversely extending head plate having an opening 4 (see FIG. 3) which desirably extends concentrically relative to the axis 50 of the closure. Arranged in that opening 4 which is formed or surrounded by a tubular connecting portion 9 is the removal sleeve 20 which in turn has the inner shell 11 with the female thread 12 and at the upper axial end a peripherally extending flange edge 16. The lower end of the removal sleeve 20 is closed by a sealing disc 13 which in turn has a peripherally extending weakening line 18. The annularly surrounding sealing limb 8 which extends downwardly or inwardly from the head plate 3 serves as a closure plug and comes into engagement with the inside wall of a container neck, on to which the screw cap is screwed by means of the thread 2.

[0049] The head plate 3 has an axially set-back portion having an edge surface 5 which surrounds the central opening in the head plate 3. The flange edge 16 of the removal sleeve 20 is disposed in the recess 6 formed in that way in the head plate, wherein the flange edge 16 and the edge surface 5 are fixedly and sealingly welded together. The flange edge 16 completely fills up the corresponding recess 6 formed by an axially set-back, annular portion of the head plate 3.

[0050] FIG. 2b is a plan view from above on to the assembled closure. It is possible to see in particular the ribbing 21, 21 at the outside of the outer shell 1, the head plate 3, the flange edge 16 which is received in a recess in the head plate 3 and the sealing disc 13 at the bottom of the removal sleeve 20, wherein that sealing disc, over a small angular region and near the outer edge of the sealing disc 13, has a raised portion 15, the function of which will be described in still greater detail hereinafter.

[0051] The details of the two closure parts can be even better seen in FIG. 3 in which the first closure part 10 and the second closure part 20 are shown separately from each other. The corresponding parts have already been substantially described in connection with FIG. 2a.

[0052] FIG. 3 further shows so-called energy direction means 17 at the underside of the flange edge 16. These involve radial ribs or limbs 17 which are of triangular cross-section and which can also be particularly clearly seen in FIG. 4b. The apex lines of those ribs 17 of triangular cross-section define the lower plane of the flange edge 16. The welding operation is implemented by inserting the inner shell 11 into the holding connection portion 9 of the first closure part 10, which extends downwardly or inwardly from the inner edge of the edge surface 5, until the apex lines of the energy direction means 17 rest on the edge surface 5. A sonotrode is brought into engagement with the flange edge and/or the edge surface 5 from opposite sides respectively, whereby the energy direction means 17, in particular the apex regions thereof, are heated and melted and produce a continuous firm weld join to the edge surface 5. In that respect the energy direction means and all adjoining elements like the recess 6 are so designed that, after the welding operation, the outside of the flange edge 16 terminates flush with the top side of the head plate 3, as can be seen in FIG. 2a.

[0053] The raised portion or projection 15 on the sealing disc 13 is limited to a relatively small angular region, as can be clearly seen in particular from FIG. 4a. The purpose of that raised portion 15 is described hereinafter with reference to FIGS. 5 and 6.

[0054] FIG. 5 shows once again the closure 100 according to the invention with a removal spout 30 screwed into the opening 14 or the thread 12.

[0055] FIG. 6 shows a partly sectional view of the closure with the removal spout screwed into the thread. When the threaded stem 32 is being screwed into the thread 12 of the inner shell the hollow-cylindrical threaded stem 32 finally comes into engagement with the raised portion 15 shortly before reaching an axial end position, in which case the torque applied to the removal spout is converted into a pressure force acting on the raised portion 15, according to the thread pitch. Conversion by the thread 12 makes it possible to exert a sufficient force on the raised portion 15 of the sealing disc 13 so that the weakening line 18, along which the sealing disc 13 is connected to the inner shell 11, tears open in the region of the raised portion 15. When the removal spout 32 is further rotated into its end position the sealing disc 13 is gradually separated away along the weakening line 18 and over almost the entire periphery, but it still remains connected to the inner shell 11 in a small angular region diametrally opposite the raised portion 15.

[0056] If desired the weakening line could also be interrupted in that region so that here a firmer connection between the sealing disc 13 and the inner shell 11 persists. If on the other hand an end abutment is provided for the threaded stem 32 there is no need to interrupt the weakening line 18 in order to prevent the sealing disc 13 from being completely separated from the removal sleeve.

[0057] The removal sleeve 30 also has a valve 33 and a removal stem 34.

[0058] It has been found that a corresponding weld connection between the flange edge 16 and the edge surface 15 is sufficiently firm to carry relatively high levels of torque, as occur in particular when the end of the threaded stem 32 comes into engagement with the raised portion 15 when the removal spout 30 is being screwed into place. The weakening line 18 initially opposes a marked resistance to the attempt to tear it open in that region, but when a corresponding torque is applied and by virtue of the torque conversion effect by virtue of the thread that resistance can be overcome. The corresponding torque however has to be carried by the welded connection between the flange edge 16 and the edge surface 15.

[0059] The securing ring 7 serves to make it apparent that a corresponding container on to which the closure 10 is screwed has been opened, because in that way the easily frangible connections between the anti-tamper ring 7 and the lower edge of the screw cap become visible.

[0060] The external shape of the entire closure 100 with an outer shell having a female thread and an inner shell having a female thread which surrounds a removal opening is known in principle. Such closures however are conventionally injection moulded in one piece with a correspondingly complex moulding tool. Separate production of the two closure parts 10 and 20 however makes it possible to produce the closure with substantially simpler tools, as are at least in part already available and which at most merely require one additional component or another in order to produce the specifically desired shape, and it is therefore possible to forego using a complex moulding tool if instead the two closure parts 10 and 20 are produced separately and they are then oriented and welded to each other, as was described hereinbefore.

[0061] For the purposes of the original disclosure it is pointed out that all features as can be seen by a man skilled in the art from the present description, the drawings and the appendant claims, even if they are described in specific terms only in connection with certain other features, can be combined both individually and also in any combinations with others of the features or groups of features disclosed herein insofar as that has not been expressly excluded or technical aspects make such combinations impossible or meaningless. A comprehensive explicit representation of all conceivable combinations of features and emphasis of the independence of the individual features from each other is dispensed with here only for the sake of brevity and readability of the description.