Closure cap for infusion or transfusion bottles

Abstract

Closure (V) for infusion or transfusion bottles, having a rubber-like sealing part (1) adapted to the bottle neck (3), the closure cap (7) being formed for under-engagement, in which it grips beneath a bead (5), on the bottle neck (3), and, furthermore, an overcap (8) being provided for securing the closure cap (7) in a positively locking manner on the bottle neck (3), wherein the sealing part (1) is arrested on the closure cap (7), wherein the sealing part (1) is exposed, in the direction of the exterior of the closure cap (7), in a piercing region (17), and the overcap (8), which also grips over the piercing region (17), is securable on the closure cap (7) in a first, reversible latching position (I) at an axial spacing (y) from the piercing region (17).

Description

[0001] The invention relates to a closure cap for infusion or transfusion bottles, having a rubber-like sealing part adapted to the bottle neck, the closure cap being formed for under-engagement, in which it grips beneath a bead, on the bottle neck, and, furthermore, an overcap being provided for securing the closure cap in a positively locking manner on the bottle neck.

[0002] German patent specification 37 15 175 C1 discloses the practice of securing the sealing part, which is configured as a stopper, by a closure cap in the form of the classic metal flanged cap. An opening which is left in the top of this closure cap allows access for a cannula or the transfusion instrument. In the original state, this opening is kept closed using a plastic lid, which at the same time forms a germ block, as an overcap. This plastic lid can be drawn off at will. This is facilitated by predetermined tearing lines which are realized by a weakening in the thickness of the material of the plastic lid.

[0003] As a substitute for the device-dependent flanging, DE 40 15 510 A1 proposes securing the closure cap, which arrests the sealing part, on the bottle neck such that it grips beneath the bead, and fixing this under-engagement by an overcap in the form of a positively locking securing means. The overcap here acts in the manner of a hoop. It is realized as an annular slide which can be displaced downward beyond the closure-cap top.

[0004] With the knowledge of these given features, it is an object of the invention to form a closure of the generic type with the aim of achieving an assembly unit which is advantageous as far as positioning is concerned and is accessible for handling purposes.

[0005] This object is achieved first and foremost in the case of a closure having the features of claim 1, this being based on the fact that the sealing part is arrested on the closure cap, that the sealing part is exposed, in the direction of the exterior of the closure cap, in a piercing region, and that the overcap, which also grips over the piercing region, can be secured on the closure cap in a first, reversible latching position at an axial spacing from the piercing region.

[0006] Such a configuration achieves a closure of the generic type with increased usage value: this is based on the creation of an assembled unit, the assembled nature being apparent both in respect of the closure-forming components being held together and in respect of defined preliminary latching while maintaining the abovedescribed spacing between closure cap and overcap. This results in surface areas being free for measures relating to sterilization of the closure. Displacing the overcap the rest of the way over the closure cap results in the closure cap being secured with defined positive locking on the bottle neck. It is also the case that the sealing part is associated with its support, namely the closure cap, with sufficient mechanical strength, or arrested thereon. Here too, the outer, free surfaces are very easily accessible for the abovementioned handling. This likewise applies to the underside of the overcap, which grips over the entire arrangement. The spacing-defining, reversible latching position has, as it were, a response threshold, which only releases the rest of the mounting travel of the overcap when the under-engagement of the closure cap on the bottle neck has taken place. An abutment is formed. The wall, as has already been indicated, descends like a blocking catch over the anchoring zone of the closure cap.

[0007] The subject matters of the rest of the claims are explained hereinbelow with reference to the subject matter of claim 1, but may also be important in their own right. It is thus provided that the closure cap and the sealing part are produced by two-component injection molding. The force of adhesion which may be obtained or set as a result has been found to be sufficient; in any case, the conventional mechanical stressing, for example within the context of the sterilization explained above, of transportation, of passage through filling sections, of movement in sorting sections, etc. is not sufficient to bring about separation. On the other hand, the parts may also be associated with one another such that they can be released at will, for example in order to be separated according to type. It is preferable for the closure cap to be injection molded over the relatively soft, preformed sealing part. This results in an effect of even independent importance: this is because the sealing part, on account of shrinkage, is positioned under elastic prestressing against the closure cap. This applies, on the one hand, in respect of the cap base which forms and also in respect of the hole-like piercing regions, which likewise narrow slightly within the context of overall shrinkage. This also results, at the same time, in welcome clamping in the direction of that portion of the sealing part which provides shaping in this respect. The invention further proposes that the closure cap has under-engagement tongues which are formed in the manner of circle segments in the circumferential direction, are provided with a latching bead and have outer latching recesses for latching the overcap, which has corresponding latching protrusions on a cylinder wall. The under-engagement tongues are individual tongues, and they can yield resiliently. The latching recesses and corresponding latching protrusions are directed toward a zigzag to sawtooth-shaped structure. The invention further proposes that the cylinder wall of the overcap, for engaging over the closure cap with latching action, has, at its lower, free end, a latching nose which projects beyond the latching protrusions of the cylinder wall. This latching nose causes the cap periphery to be thickened there and thus provides a stable support at the rear for the second, basically irreversible latching position of the closure. It is then further provided that the closure cap, associated with a closure-cap top, has a latching recess for reversible latching with the latching nose of the overcap. The formation of the latching recess, associated with the closure-cap top, results in the largest possible surface area of the preassembled unit being free for sterilization. In specific terms, the latching recess is disposed in a cross-section beneath the closure-cap top, i.e. in the vicinity of the top. The overcap has an overcap top which grips over the piercing region. The accessibility of the piercing region, which is necessary during use, is achieved by straightforward means in that formed by a weakening line in the overcap top is a tear-open tab, which extends to the outer periphery of the overcap top. The peripheral gripping extension here usually has a separating location, advantageously forming the access to the interior of the pre-latched unit. It is advantageous for two diametrically opposite tear-open tabs, each extending as far as a central region of the overcap top, to be formed. Furthermore, it is proposed that a tear-open tab is associated in each case with a piercing region, which is enclosed around the periphery by the closure-cap top. The piercing regions are thus distributed, as it were, like islands in the top of the cap. It is further provided that the overcap is secured against rotation on the closure cap. Inherent features may be included for the purpose of forming the means which secure against rotation. This is realized in that the securing against rotation is achieved by vertical ribs which are formed on the inside of the cylinder wall of the overcap and engage in corresponding vertical grooves of the closure cap. The specified requirements indicated apply to the vertical grooves. The configuration in this respect is characterized in that a vertical groove is also formed on the closure cap by the separating region between two circle-segment-like under-engagement tongues. Furthermore, an advantageous configuration consists in that the vertical groove continues to the upper side of the closure-cap top, leaving behind a residual portion of the wall of the closure cap. The residual portion is the result of a slightly frustoconical transition of the wall of the closure cap in the direction of the closure-cap top. An advantageous variant of the subject matter of the invention, finally, consists in that the sealing element terminates at a radial spacing from the inside of the annular wall of the closure cap. Such a peripheral, circumference-following annular gap may easily also be included in production. The contact-free positioning in relation to the inside there can be used if it is not intended to use the above-mentioned clamping in this region and if it is desired to minimize the surface areas which adhere to one another. Moreover, the radial spacing, which extends up to the top of the closure cap, can be utilized to good effect for levering out the sealing part in order for the cap components to be separated according to type. The sealing part can be levered like an oyster out of the shell.

[0008] The subject matter of the invention is explained in more detail hereinbelow with reference to an exemplary embodiment illustrated in the drawing, in which:

[0009] FIG. 1 shows, in enlarged illustration, to be precise half in section, the closure according to the invention, associated with a bottle neck,

[0010] FIG. 2 shows, in perspective illustration, the associated closure,

[0011] FIG. 3 shows an illustration as in FIG. 2, but in a broken-away state,

[0012] FIG. 4 shows, again in a schematic illustration, detached tear-open tabs of the closure, one of them in longitudinal section,

[0013] FIG. 5 shows the associated overcap, on its own and in a broken-away state,

[0014] FIG. 6 shows the matching closure cap, likewise in a broken-away state,

[0015] FIG. 7 shows the sealing part as a preform,

[0016] FIG. 8 shows the bottle neck of an infusion or transfusion bottle, also in a broken-away state in each case,

[0017] FIG. 9 shows the preassembled unit of the closure cap with its parts positioned at an axial spacing from one another, once again in a broken-away state,

[0018] FIG. 10 shows the bottle neck oriented appropriately for positioning purposes,

[0019] FIG. 11 shows the closure and bottle plugged together, as yet unsecured,

[0020] FIG. 12 shows the same closure and bottle plugged together, but this time secured by the overcap displaced into its end position,

[0021] FIG. 13 shows a variant of the closure with a centrally-located piercing region in a position according to FIG. 12, but without the bottle neck being illustrated,

[0022] The underside of the sealing part 1, which is directed toward the mouth opening 10, has a planar-surface depression. The depression is designated 11.

[0023] The closure cap 7, which consists of hard and tough plastic (PP), is, like the overcap 8 of the same material, of cup-like configuration. The closure cap forms a shell part which encloses the sealing part 1 on the outside, and comprises a closure-cap top 12 which is substantially planar in the center. This top merges into an annular wall 13. The top 12 and annular wall 13 adjoin one another at an angle of over 90°; with the corner as the vertex, this angle encloses approximately 110°. This results in a slightly frustoconical orientation for the shell-forming shoulder of the annular wall 13 and, in respect of the portion on the closure-cap top, in a periphery which slopes down at a slightly acute angle (see FIG. 1). The shoulder is designated a and the portion is designated b. They have the same leg length.

[0024] The annular wall 13 continues, in the direction of its free, lower end, into under-engagement tongues 14. Following the circumferential direction of the closure cap 7, these tongues are in the form of a ring of circle-segment-like, resiliently deflectable individual tongues with an excellent restoring force. The arcuate course taken by these tongues, Moreover, has a stabilizing effect. In specific terms, the under-engagement means is an integrally formed latching bead 15 which is exposed on the bottle-neck side. These latching beads 15 snap with anchoring action beneath the undercut flank 6 of the bottle neck 3. The flank profiles of the parts 6 and 15 are coordinated with one another. They slope up in the outward direction approximately at an angle of around 40° in relation to a horizontal.

[0025] FIG. 14 shows the closure cap with associated sealing part, illustrating the configuration of the means on the closure cap for securing against rotation, formed from the longitudinal slots which are present anyway and from the vertical grooves starting in the vicinity of the closure-cap top, and

[0026] FIG. 15 shows a further variant of the closure in an illustration as in FIG. 1.

[0027] The non-metallic closure V illustrated comprises a double cap, the parts of which can be fitted one inside the other, with a sealing part 1 captured therein.

[0028] The sealing part 1 consists of thermoplastic rubber (TPE) and is of basically disk-like configuration. Its periphery 2 is thickened in the direction of a bottle neck 3.

[0029] A bottle 4, which can be used as an infusion or transfusion bottle, consists of glass. The free end of the bottle neck 3 widens radially outward into a bead 5. The latter forms an undercut flank 6. The actual closure cap 7 of the closure V engages beneath this undercut flank. The overcap, which grips over the closure cap (7) is designated 8.

[0030] The end surface 9, which is widened by the bead 5, is configured, with rotational symmetry, in the manner of a pitched roof. The longer flank of the pitched roof slopes down in the outward direction. The gable is rounded convexly with a shorter flank, which slopes down more steeply, connection into the mouth opening 10 of the bottle neck 3.

[0031] The separating regions which cut the individual engagement tongues 14 free are realized as longitudinal slots 16 of the annular wall 13. The base of the longitudinal slots 16 terminates approximately in the same plane as the exposed ridge of the end surface 9 of the bottle neck 3.

[0032] Pierceable regions are left in the closure-cap top 12. According to one version, the corresponding piercing region 17 is located in the center of the closure V, in the form of a circular hole 18, the radius point of which intersects the longitudinal center axis x-x of the basically rotationally symmetrical closure V.

[0033] The central piercing region is embodied in the version illustrated as from FIG. 9. The construction is otherwise identical with the basic version, beginning with FIG. 1. The designations are used analogously, in some cases without being repeated in the text.

[0034] As can be gathered clearly from FIG. 6, the basic version provides two such piercing regions 17 in the closure-cap top 12.

[0035] The sealing part 1 projects with a cavity-filling amount of rubber-like substance into the respective hole 18, which circumscribes the piercing region 17.

[0036] It is also possible, however, for the hole 18 to be kept closed by way of a correspondingly filling protrusion projecting in a cavity-filling manner into the through-passage or the hole 18 from the underside and/or inside of the top 19 of the overcap 8. In this case, the sealing part 1 does not have the disk-like filler body 20 disposed on its outside.

[0037] It is preferred in production terms if the sealing part 1 is captured on the closure cap 7, the sealing part 1 being exposed, in the direction of the exterior of the closure cap 7, over the circumference of the piercing region 17. Expose means, or includes, leaving behind a practicable pierceability, so that this term is also intended to be understood in functional terms as a thin coating remaining on the upper side.

[0038] The closure cap 7 and sealing part 1 are produced by two-component injection molding. The preformed, relatively soft injection molding for the sealing part 1 is introduced for shaping action into the (injection) mold and is encapsulated by the relatively harder material used for producing the closure cap 7. This results in the parts 1, 7 being captured on one another as mentioned above, it being possible to set the degree to which the substances adhere to one another such that the sealing part 1 can be released without sticking to the body which is hard enough to be self-supporting, in other words the closure cap 7.

[0039] Such a production process, moreover, gives rise to the surprising effect of the parts 1, 7 being held together mechanically, to be precise on account of the shrinkage f the cup-forming material or part fitted onto the sealing part 1, so that the closure cap 7 is positioned under elastic prestressing against the sealing part 1 or vice versa. The outer peripheries of the disk-like sealing part 1 are thus clamped by the shell-forming region of the annular wall 13, that is to say the shoulder a. The same applies in respect of the slightly contracting holes 18, which clamp the filler body or bodies 20 around the periphery.

[0040] The closure cap 7 fitted with the sealing part in this way is combined with the overcap 8 by way of a pre-positioning operation (see FIG. 9).

[0041] In this position, the overcap 8 is associated with the closure cap 7 from the outset in a straddling manner appropriate for the two to be fitted one inside the other. This docking position is defined by a first, reversible latching position, with an axial spacing y being left between the inside of the top 19 of the overcap 8 and the upper side of the closure-cap top 12, the upper side containing the piercing region or regions 17. This first, reversible latching position is indicated by I in the drawing.

[0042] A unit 1/7/8 assembled in this way is immune to conventional mechanical loading, i.e. this preassembled unit can be conveyed and sorted, but in particular, if required, supplied for conventional sterilization. Outer as well as inner accessibility is provided here over the largest possible surface area since, on the one hand, the parts 7 and 8 have not yet been fitted one inside the other and, moreover, they allow the space produced by the spacing y to be reached via the openings 21 beneath tear-open tabs 22, these openings being left in the region of the overcap top 12.

[0043] As can be gathered, the spacing y defined by latching leaves the under-engagement tongues 14 free and fully resiliently deflectable. The closure V is positioned on the bottle neck 3. As a result of positioning pressure exerted from above, the resiliently deflecting under-engagement tongues 14 pass over the bead 5 of the bottle neck 3, this bead having a larger cross-section, until, finally, the latching beads 15 snap beneath the undercut surface 6. The latching force which retains the parts 7 and 8 at spacing y is set up in respect of a surmountable threshold such that it is always only after the abovedescribed anchoring operation that the overcap 8 advances further over the lateral wall of the closure cap 7.

[0044] In structural terms, in respect of the first, reversible latching position I, the closure cap 7 has a latching recess 23. This is preferably located as an encircling groove on the outside of the annular wall 13, to be precise in the vicinity of the closure-cap top 12, and more precisely by beneath a cross-sectional plane of the closure V which is occupied by the top 12. The corresponding mating latching means forms a latching nose 24 on the inside of a cylinder wall 25 of the cup-like overcap 8.

[0045] With the parts 7 and 8 fitted one inside the other (see, for example, FIG. 1), the said latching nose 24 snaps beneath a beveled blocking flank 26 on the rear of the latching bead 15. In this position, the cylinder wall 23 encloses the ring of under-engagement tongues 14 in a hoop-like manner, and the ring thus secures the closure V satisfactorily on the bottle neck 3 of the infusion or transfusion bottle. This irreversible latching position secured by the body 8, which for all practical purposes forms a slide ring, is designated II. It acts like flanging, but without the means for plastic deformation.

[0046] The outside of the annular wall 13 and the inside of the cylinder wall 25 are roughened from the base 16′ of the longitudinal slots 16 to the latching nose 24. This roughening is of an ordered, positively lockable nature in the form of a horizontally oriented tooth structure. More precisely, this has the structural appearance, in detail, of the closure cap 7 having outer latching recesses 27, in the form of depressions, in the circumferential direction of the circle-segment-like under-engagement tongues 14. Latching protrusions 28, in the form of ribs, which are formed on the inside of the cylinder wall 25, engage in these latching recesses. The washboard-like contour can be gathered in detail in the drawings. The latching protrusions 28 have a smaller radially oriented height than the latching noses 24.

[0047] Coming back now to the tear-open tab or tear-open tabs 22 in the overcap top 19, it should be noted that these have a tongue-like outline configuration. Formation of the desired separating gap is aided by a weakening line 29. This is a notch-like trench on the upper side, the trench base leaving behind a fraction as a material bridge. In the region of the peripheral openings 21, even this region is broken, so as to aid initial tearing. A freely projecting end zone of the tear-open tabs 22 also provides assistance in this respect. The projection here need not go beyond the general diameter of the overcap 8 if, as is illustrated, the lateral wall thereof is flattened in this end region. The corresponding hollow is designated 30.

[0048] As can be gathered, two diametrically opposite tear-open tabs 22 are realized in the basic version. These tabs terminate, with oppositely directed rounded formations, before a central region of the overcap top 19. The procedure here is such that a tear-open tab 22 is associated in each case with a piercing region 17, which is enclosed around the periphery by the closure-cap top 12.

[0049] In order to achieve congruent alignment of the piercing region 17 and tear-open tab 22 during mounting, the overcap 8 is retained on the closure cap 7 such that it is secured against rotation, this measure not being required, of course, if the closure V has a central piercing region. 17 and a tear-open tab 22 which continues over the diameter.

[0050] Securing against rotation is achieved by a vertical rib 31 which is integrally formed on the inside of the cylinder wall 25 of the overcap 8. This vertical rib projects beyond the height of the latching protrusions 28 and extends into the cross-sectional region of the annular wall 13 of the closure cap, more precisely into the cross-sectional region of the longitudinal slots 16.

[0051] It is advantageous for two axially oriented vertical ribs 31 to be integrally formed diametrically opposite one another.

[0052] As a result of the conical-shell-forming portion of the annular wall 13, which is thus not slit by 16, the longitudinal slot 16, in this region occupied by the shoulder a, is continued as a vertical groove 32 which is open in the outward direction. Since this portion, as has been explained above, tapers frustoconically in the direction of the upper side of the closure V, this shell wall is maintained, albeit with a smaller cross-section. The corresponding structural precautionary measure of the vertical grooves 32 also being formed on the closure cap 7 by the separating region between two adjacent circle-segment-like under-engagement tongues 14 can be gathered from the illustrations. FIG. 14 shows particularly clearly that the vertical groove 32 continues to the upper side of the closure-cap top 12, to be precise leaving behind a residual portion 33 of the annular wall 13 of the closure cap 7, this residual portion being indicated there.

[0053] Provision is made for a total of eight blocking engagement spaces 16/32 which are distributed at equal angles and of which two diametrically opposite spaces are filled by vertical ribs 31.

[0054] The spatial positioning of the holes 18 in relation to the blocking engagement spaces is such that the holes 18 are fully covered, as desired, by the tear-open tabs 32 gripping over them.

[0055] The correct plug-in alignment can be perceived, for all practical purposes, by virtue of the overcap 8 being rotated slightly in relation to the closure cap 7. On the other hand, however, it is also possible for the blocking engagement spaces 16/32 which are not utilized to be blocked from the start. In the case of a central hole 19, in contrast, there is no need for such a precautionary measure.

[0056] For the case where the substance forming the sealing part 1 is injected into a closure cap 7 which has already been formed, the TPE substance may be opened out via the hole or holes 18. FIG. 14, however, shows a specification where the injection is carried out via one of two special holes 34 located in the vicinity of the periphery, the other hole functioning as an air vent. The holes 34, which are placed along a diameter line of the closure-cap top 12, have only a fraction of the inside diameter of the holes 18 which form the filler bodies 20. The ratio is around 1:6. The holes 18 and 34 are circular in each case. They may be cylindrical, frustoconical or undercut.

[0057] The further variant of the closure V which is illustrated in FIG. 15 largely corresponds, in structural terms, to the basic version, which has been described in detail. The reference numerals are used analogously, in some cases without the variant which is applicable to the basic version being repeated in the text.

[0058] The differing configuration consists in the periphery of the substantially disk-like sealing element 1 now terminating at a radial spacing z from the inside of the annular wall 13 of the closure cap 7. The substantially cylindrical periphery 35 of the sealing element 1 is positioned in a contact-free manner in front of the inside 36 of the annular wall 13, the inside 36 circumscribing it. The resulting annular gap formed all the way around the circumference is designated 37. In the basic version, however, the annular gap 37 is only present in rudimentary form. It extends only over a fraction of the shell-forming, vertical length of the annular wall 13, to be precise to just behind the longitudinal-slot base 16′.

[0059] On account of the portion a of the annular wall 13 tapering in a slightly frustoconical manner in the direction of the closure-cap top 12, the said annular gap 37 tapers in the direction of the top-side gap base. Part of this gap base is formed by the other portion, designated b, of the closure cap 7. As can be gathered, the slot base is realized as a contact-free zone between sealing part 1 and annular wall 13 or top 12.

[0060] The annular gap 37 may be utilized to the effect that it forms a jamming-prevention means between the sealing part 1 and the closure cap 7. The annular gap 37 is dimensioned in the radial direction such that it is also the case that it does not become blocked following the abovedescribed shrinkage process. It thus remains as an access point for the application of a removal tool, for example, in order for the parts which form the closure V to be separated according to type as desired.

[0061] On the other hand, however, in respect of the latching recess 23 of the closure cap 7, there is also a certain radially inwardly directed clearance for resilient deflection.

[0062] In respect of the piercing region 17, the means are used as has been explained above. If, in a modification of the piercing region described, the hole 18 is not filled by a filler body 20 of the sealing part 1, the procedure may, conversely, be such that a corresponding hole-filling protrusion extend from the overcap top 19 or, as is illustrated, from the underside of the tear-open tab 22. Such a protrusion may, of course, be cylindrical or frustoconical. In the latter case, the hole 18 is then of matching configuration, that is to say in the form of a funnel. The rear of the protrusion formed by the overcap 8 may contain an indent extending from the upper side.

[0063] The operation of positioning the holes in the correct location is always ensured by the abovedescribed angle-defining means such as the vertical rib 31 and vertical groove 32.

[0064] All features disclosed are (in themselves) pertinent to the invention. The disclosure content of the associated/attached priority documents (copy of the prior application) is hereby also included in full in the disclosure of the application, also for the purpose of incorporating features of these documents in claims of the present application.

Claims

1-17 (cancelled)

18. Closure (V) for infusion or transfusion bottles, having a rubber-like sealing part (1) adapted to a bottle neck (3), a closure cap (7) being formed for under-engagement, in which it grips beneath a bead (5), on the bottle neck (3), and, furthermore, an overcap (8) being provided for securing the closure cap (7) in a positively/form locking manner on the bottle neck (3), wherein the sealing part (1) is arrested on the closure cap (7), wherein the sealing part (1) is exposed, in direction of an exterior of the closure cap (7), in a piercing region (17), and the overcap (8), which also grips over the piercing region (17), is securable on the closure cap (7) in a first, reversible latching position (I) at an axial spacing (y) from the piercing region (17).

19. Closure according to claim 18, wherein the closure cap (7) and the sealing part (1) are produced by two-component injection molding.

20. Closure according to claim 19, wherein the sealing part (1), on account of shrinkage, is positioned under elastic prestressing against the closure cap (7).

21. Closure according to claim 18, wherein the closure cap (7) has under-engagement tongues (14) which are formed in a manner of circle segments in circumferential direction, are provided with a latching bead (15) and have outer latching recesses (27) for latching the overcap (8) which has corresponding latching protrusions (28) on a cylinder wall (25).

22. Closure according to claim 21, wherein the cylinder wall (25) of the overcap (8), for engaging over the closure cap (7) with latching action, has, at its lower, free end, a latching nose (24) which projects beyond the latching protrusions (28) of the cylinder wall (25).

23. Closure according to claim 22, wherein the closure cap (7), associated with a closure-cap top (12), has a latching recess (23) for reversible latching with the latching nose (24) of the overcap (8).

24. Closure according to claim 23, wherein the latching recess (23) is disposed in a cross-section beneath the closure-cap top (12).

25. Closure according to claim 18, wherein the overcap (8) has an overcap top (19) which grips over the piercing region (17).

26. Closure according to claim 25, wherein formed by a weakening line (29) in the overcap top (19), is a tear-open tab (22), which extends to outer periphery of the overcap top (19).

27. Closure according to claim 26, wherein two diametrically opposite tear-open tabs (22), each extending as far as a central region of the overcap top (19), are formed.

28. Closure according to claim 18, wherein a tear-open tab (22) is associated in each case with a piercing region (17), which is enclosed around the periphery by a closure-cap top (12).

29. Closure according to claim 18, wherein the overcap (8) is secured against rotation on the closure cap (7).

30. Closure according to claim 29, wherein the securing against rotation is achieved by vertical ribs (31) which are formed on an inside of a cylinder wall (25) of the overcap (8) and engage in corresponding vertical grooves (32) of the closure cap (7).

31. Closure according to claim 30, wherein a vertical groove (32) is also formed on the closure cap (7) by a separating region between two circle-segment-like under-engagement tongues (14).

32. Closure according to claim 31, wherein the vertical groove (32) continues to an upper side of a closure-cap top (12), leaving behind a residual portion (33) of an annular wall (13) of the closure cap (7).

33. Closure according to claim 18, wherein there is a slightly frustoconical transition of a wall of the closure cap (7) in a direction of a closure-cap top (12).

34. Closure according to claim 18, wherein the sealing part (1) terminates at a radial spacing (z) from an inside (36) of an annular wall (13) of the closure cap (7).

35. Closure according to claim 21, wherein a securing against rotation is achieved by vertical ribs (31) which are formed on an inside of the cylinder wall (25) of the overcap (8) and engage in corresponding vertical grooves (32) of the closure cap (7).

36. Closure according to claim 21, wherein a vertical groove (32) is also formed on the closure cap (7) by a separating region between two circle-segment-like under-engagement tongues (14).