Self-opening closure with optimized force transmission

Abstract

The invention relates to a self-opening closure with a pouring spout (12), a self-opening sleeve (20) which is guided in the connector in a helical manner, and a cover (30) which covers the pouring spout (12). A driver cam (24) is formed on the self-opening sleeve, said driver cam defining a guide surface (241). The cover has a driver (34) which defines a front edge (341). The front edge interacts with the guide surface of the driver cam. The front edge and the guide surface are inclined by the same angle of inclination relative to the longitudinal axis in order to allow an optimal force transmission between the cover and the self-opening sleeve. Additionally, the guide surface can be designed in a concave manner, and the front edge of the driver can be rounded in a corresponding manner in order to prevent a radial deflection of the driver towards the inside.

Claims

1. A self-opening closure, comprising: a tubular pouring spout, which defines a longitudinal axis and is provided on its inner side with an internal thread having a pitch angle, a cap, which upwardly covers the pouring spout and which, for the purpose of opening the closure, is rotatable in an opening direction and, for the purpose of reclosing the closure, is rotatable in a closing direction opposite to the opening direction, wherein the cap comprises at least one driver, which defines a front edge; and a self-opening sleeve, which is provided with an external thread that engages in the internal thread of the pouring spout, and which on its inner side comprises at least one driving cam, wherein the driving cam defines a guide face which, when the closure is opened for the first time, cooperates with the front edge of the driver in order to move the self-opening sleeve in the pouring spout in a screw-like manner downward out of an starting position into an opening position, wherein the front edge runs inclined downward by a first angle of inclination relative to the longitudinal axis, wherein the guide face runs inclined by the same angle of inclination as the front edge relative to the longitudinal axis, and wherein the first angle of inclination of the front edge of the driver is greater than or equal to the pitch angle of the internal thread of the pouring spout.

2. The self-opening closure as claimed in claim 1, wherein the guide face is configured with a continuously concave curvature with respect to a radial direction, so that it embraces the front edge of the driver when the closure is opened for the first time.

3. The self-opening closure as claimed in claim 2, wherein the front edge of the driver is convexly curved.

4. The self-opening closure as claimed in claim 2, wherein the front edge of the driver has at least in some areas a shape which is complementary to the shape of the guide face of the driving cam.

5. The self-opening closure as claimed in claim 2, wherein the guide face, when the closure is opened for the first time, bears along the whole of its length against the front edge of the driver.

6. The self-opening closure as claimed in claim 1, wherein the driving cam is of ramp-shaped configuration before the guide face with respect to the opening direction, with a slide face directed inward obliquely to the opening direction, which slide face merges smoothly into an inner cylindrical lateral surface of the self-opening sleeve, and wherein the driver, when the closure is reclosed, slides over the slide face of the driving cam.

7. The self-opening closure as claimed in claim 6, wherein the driver defines a rear edge, which runs inclined by a second angle of inclination relative to the longitudinal direction, wherein the second angle of inclination is greater in magnitude than the first angle of inclination.

8. The self-opening closure as claimed in claim 1, wherein the self-opening sleeve comprises a supporting ring, on which the external thread is configured, as well as at least a first tooth, which extends downward protruding from the supporting ring, and which defines a front cutting edge.

9. The self-opening closure as claimed in claim 8, wherein the self-opening sleeve comprises a second tooth, which, with respect to the opening direction, follows the first tooth at an angular distance of 90-180, measured from tip to tip, and wherein the self-opening sleeve otherwise comprises no further teeth.

10. The self-opening closure as claimed in claim 9, wherein the second tooth extends downward with respect to the longitudinal axis equally as far as the first tooth.

11. The self-opening closure as claimed in claim 9, wherein the second tooth has a front cutting edge, which runs substantially at the same angle of inclination relative to the longitudinal axis as the front cutting edge of the first tooth.

12. The self-opening closure as claimed in claim 9, wherein between the first tooth and the second tooth is continuously configured a ring segment, which extends downward from the supporting ring, wherein this ring segment, after the closure has been opened for the first time, projects jointly with the first and second tooth downward from the pouring spout.

13. The self-opening closure as claimed in claim 1, wherein the self-opening sleeve has a peripheral region in which the self-opening sleeve, after the closure has been opened for the first time, projects at most by about 1 mm downward from the pouring spout.

14. The self-opening closure as claimed in claim 1, wherein the self-opening sleeve has on its inner side a fixing cam, and wherein the driver, before the closure has been opened for the first time, is disposed between the driving cam and the fixing cam in such a way that the self-opening sleeve is movable by at most 20 in relation to the screw cap.

15. The self-opening closure as claimed in claim 1, wherein the self-opening sleeve has a peripheral region in which the self-opening sleeve, after the closure has been opened for the first time, does not project downward from the pouring spout.

16. The self-opening closure as claimed in claim 1, wherein the self-opening sleeve has on its inner side a fixing cam, and wherein the driver, before the closure has been opened for the first time, is disposed between the driving cam and the fixing cam in such a way that the self-opening sleeve is immovable in relation to the screw cap.

17. A self-opening closure, comprising: a tubular pouring spout, which defines a longitudinal axis and is provided on its inner side with an internal thread having a pitch angle, a cap, which upwardly covers the pouring spout and which, for the purpose of opening the closure, is rotatable in an opening direction and, for the purpose of reclosing the closure, is rotatable in a closing direction opposite to the opening direction, wherein the cap comprises at least one driver, which defines a front edge; and a self-opening sleeve, which is provided with an external thread that engages in the internal thread of the pouring spout, and which on its inner side comprises at least one driving cam, wherein the driving cam defines a guide face which, when the closure is opened for the first time, cooperates with the front edge of the driver in order to move the self-opening sleeve in the pouring spout in a screw-like manner downward out of an starting position into an opening position, wherein the front edge runs inclined downward by a first angle of inclination relative to the longitudinal axis, wherein the guide face runs inclined by the same angle of inclination as the front edge relative to the longitudinal axis, wherein the driving cam is of ramp-shaped configuration before the guide face with respect to the opening direction, with a slide face directed inward obliquely to the opening direction, which slide face merges smoothly into an inner cylindrical lateral surface of the self-opening sleeve, and wherein the driver, when the closure is reclosed, slides over the slide face of the driving cam.

18. The self-opening closure as claimed in claim 17, wherein the driver defines a rear edge, which runs inclined by a second angle of inclination relative to the longitudinal direction, wherein the second angle of inclination is greater in magnitude than the first angle of inclination.

19. A self-opening closure, comprising: a tubular pouring spout, which defines a longitudinal axis and is provided on its inner side with an internal thread having a pitch angle, a cap, which upwardly covers the pouring spout and which, for the purpose of opening the closure, is rotatable in an opening direction and, for the purpose of reclosing the closure, is rotatable in a closing direction opposite to the opening direction, wherein the cap comprises at least one driver, which defines a front edge; and a self-opening sleeve, which is provided with an external thread that engages in the internal thread of the pouring spout, and which on its inner side comprises at least one driving cam, wherein the driving cam defines a guide face which, when the closure is opened for the first time, cooperates with the front edge of the driver in order to move the self-opening sleeve in the pouring spout in a screw-like manner downward out of an starting position into an opening position, wherein the front edge runs inclined downward by a first angle of inclination relative to the longitudinal axis, wherein the guide face runs inclined by the same angle of inclination as the front edge relative to the longitudinal axis, wherein the self-opening sleeve comprises a supporting ring, on which the external thread is configured, as well as at least a first tooth, which extends downward protruding from the supporting ring, and which defines a front cutting edge, wherein the self-opening sleeve comprises a second tooth, which, with respect to the opening direction, follows the first tooth at an angular distance of 90-180, measured from tip to tip, and wherein the self-opening sleeve otherwise comprises no further teeth, and wherein between the first tooth and the second tooth is continuously configured a ring segment, which extends downward from the supporting ring, wherein this ring segment, after the closure has been opened for the first time, projects jointly with the first and second tooth downward from the pouring spout.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention are described below on the basis of the drawings, which serve merely for illustration and should not be interpreted restrictively. In the drawings:

(2) FIG. 1 shows a perspective view of a closure according to a first embodiment in its opening position;

(3) FIG. 2 shows a further perspective view of the closure of FIG. 1;

(4) FIG. 3 shows a central longitudinal section through the closure of FIG. 1 in its starting position;

(5) FIG. 4 shows a perspective view of the base of the closure of FIG. 1;

(6) FIG. 5 shows a perspective view of the self-opening sleeve of the closure of FIG. 1;

(7) FIG. 6 shows a perspective view of the cap of the closure of FIG. 1;

(8) FIG. 7 shows a perspective view of the closure of FIG. 1 in its starting position;

(9) FIG. 8 shows a perspective view of a self-opening sleeve of a closure according to a second embodiment, having only one tooth; and

(10) FIG. 9 shows a perspective view of a self-opening sleeve of a closure according to a third embodiment, having three teeth.

DESCRIPTION OF PREFERRED EMBODIMENTS

(11) In FIGS. 1 to 7, a first embodiment of a closure according to the invention is illustrated in different views. This variant of the closure is particularly well suited to composite packagings having a cardboard layer with prepunched opening which is overlaminated with plastics films and, if need be, a metal foil. The closure consists of a base 10, which in FIG. 4 is represented in isolation, of a self-opening sleeve 20, which in FIG. 5 is represented in isolation, and of a cap 30, which in FIG. 6 is represented in isolation.

(12) The base 10 has a base plate 11 for connecting the closure to a packaging wall (not represented). The base plate 11 has a circular opening, which is surrounded by a tubular, cylindrical pouring spout 12. The pouring spout 12 extends upward from the base plate 11 up to a circumferential, circular upper rim 13. The pouring spout 12 defines, due to its cylindrical basic shape, a central longitudinal axis L (see FIG. 3), as well as an opening direction U along its periphery (see FIG. 4). A radial direction is accordingly a direction which extends from the central longitudinal axis L outward in the direction of the peripheral wall of the pouring spout 12.

(13) On the inner side of the pouring spout 12 is configured an internal thread 14, which has a pitch angle relative to a plane running perpendicular to the longitudinal axis 11. In the present example, this is constituted by a double thread having a pitch angle of about 6.5 and about 1.5 windings. On the lower end of the thread 14 is configured a holding cam 19. On the outer side of the pouring spout 12 is configured an external thread 15, which has a significantly smaller pitch angle than the pitch angle of the internal thread. Beneath the external thread are disposed on the base 10 a plurality of retaining webs 16, which cooperate with a guarantee band described in further detail below. Ramps 17 on the base plate 11 aid the transport of the closure in an application device. Reinforcing ribs 18 strengthen the base plate 11 on its bottom side.

(14) The self-opening sleeve 20 has a supporting ring 21, on which two teeth 22, 23 are configured. The supporting ring 21 is provided on its outer side with an external thread 25, which is complementary to the internal thread 14 of the pouring spout 12. In the present example, the (likewise double) external thread 25 extends over somewhat more than half a winding.

(15) On the inner side of the supporting ring 21 is configured a hook-shaped driving cam 24. This defines a guide face 241, which is inclined to the longitudinal axis L and is not configured flat, but concavely curved, with respect to the radial direction. The guide face 241 has no sharp bends whatever. The guide face is about 4 mm long. Before the guide face 241, viewed in the opening direction, the driving cam 14 is of wedge-shaped or ramp-shaped configuration and forms a ramp-like slide face 242 which is inclined inward in the opening direction. This slide face 242 has no steps or bends and merges steplessly into the cylindrical inner peripheral face of the supporting ring 21.

(16) At some distance from the driving cam, situated behind the driving cam in the opening direction, is found a fixing cam 243, which is discernible in FIG. 7.

(17) Each of the two teeth 22, 23 has a front cutting edge 221 and 231 respectively, as well as a blunt rear edge 222, 232. The front cutting edge 221 or 231 is inclined downward by an angle relative to the longitudinal axis. In the present example, the angle of inclination is about 18. The rear edge 222 or 232 runs at an angle to the longitudinal axis L which is greater than the angle . In the present example, this angle is about 65. The two teeth have a distance apart of about 120 along the peripheral direction. Between the first and the second tooth is configured a ring segment 26 (i.e. a material region in the shape of a cylinder wall segment), which extends downward from the supporting ring 21. Before the first tooth 22 and behind the second tooth 23, viewed in the opening direction, are configured further ring segments 27, which extend downward from the supporting ring 21, however, only by a comparatively small section. Between these two ring segments 27 there is a gap, which defines a residue emptying region 28 and the function of which is explained in greater detail below. The teeth 22, 23 and lateral wall regions 26, 27 are offset slightly radially inward in relation to the supporting ring 21. Between them is configured, on the inner side of the self-opening sleeve 20, a circumferential edge 29, which, in the residue emptying region 28, at the same time forms the bottom edge of the self-opening sleeve 20.

(18) The cap 30 has a cover wall 31 and a circumferential, substantially cylindrical side wall 32. On the inner side of the side wall 32 is configured an internal thread 33, which cooperates with the external thread 15 on the pouring spout 12. From the cover wall 31, a single driver 34 extends axially downward. The driver 34 forms a front edge 341 and a rear edge 342. The front edge 341 is inclined relative to the longitudinal axis L by an angle . The angle amounts in the present example to about 20. It is thus significantly greater than the pitch angle of the internal thread 14 in the pouring spout 12. The rear edge 342 is inclined relative to the longitudinal axis L by an angle . The angle is in the present case about twice as large in magnitude as the angle and has the opposite sign hereto. The driver has the basic shape of a cylinder wall segment, wherein the helical front edge of the cylinder wall segment forms the aforementioned front edge 341 of the driver and the helical rear edge of the cylinder wall segment forms the aforementioned rear edge 342 of the driver. The bottom edge of the driver runs perpendicular to the longitudinal axis. The front edge 341 of the driver 34 is configured, in a region extending over the entire length of the front edge 341, complementary to the guide face 241 of the driving cam 24. As a result, this region of the front edge 341 bears squarely against the guide face 241.

(19) On the lower end of the side wall 32 of the cap 30 is configured a guarantee band 35 having inwardly directed retaining cams 36. Between side wall 32 and guarantee band 35, a cut is executed prior to fitting (slitting), so that the guarantee band remains connected to the rest of the cap only by thin material regions. The retaining cams 36 cooperate with the retaining webs 16 on the base 10 in order to prevent the co-rotation of the guarantee band 35 when the closure is opened for the first time. As a result, upon first-time opening, the guarantee band 35 is separated from the rest of the cap, falls downward onto the base plate 11 and thus indicates the first opening. Possible other configurations of the guarantee band are known from the prior art.

(20) The closure is preferably produced in two pieces, wherein the base 10 and the self-opening sleeve 20 are produced in one piece in a single injection mold, for example from HDPE. To this end, the self-opening sleeve 20, following production, is initially connected on its top edge by narrow material bridges 201 (FIG. 5) to the bottom side of the base 10; these material bridges are broken upon fitting of the closure. The cap 30 is produced in a separate injection mold and can consist of the same material as the base 10 and the self-opening sleeve 20. Such a two-piece production of the closure is in principle known from the prior art.

(21) The closure is fitted by pressing the self-opening closure 20 axially into the pouring spout 12 and pressing the cap 30 axially onto the pouring spout 12. The closure is then in its starting position, which is illustrated in FIGS. 3 and 7. The self-opening sleeve 20 is here fully within the pouring spout 12. As can be seen in FIG. 7, in this position the driver 34 is disposed between the driving cam 24 and the fixing cam 243. As a result, unintended rotation of the self-opening 20 in the fitted closure is prevented. In this form, the closure is positioned above an overlaminated opening of the packaging wall and fastened (for example welded or glued) onto the packaging wall.

(22) For the first-time opening of the packaging, the user turns the cap 30 counterclockwise (i.e. in the opening direction U). By means of the driver 34 and the driving cam 24, the cap 30 here transports the self-opening sleeve 20 and sets this likewise in rotation. The front edge 341 of the driver 34 bears on the guide face 241 of the driving cam 24 over the entire length of the driving cam 24 and slides on said guide face. Due to the threaded joint between the self-opening sleeve 20 and the pouring spout 12, the self-opening sleeve 20 moves helically downward. The teeth 22, 23 here pierce the laminated films, and, if need be, the metal layer, on the opening of the packaging wall, and afterward further cut these open. The cap 30 transports the self-opening sleeve 20 until such time as this has reached its lower opening position, as is illustrated in FIG. 1. At this point, the external thread 15 on the pouring spout 12 and the internal thread 33 on the cap 30 cease to engage in each other, and the cap 30 can be pulled off the pouring spout 12. The self-opening sleeve is prevented by the holding cam 19 from being further rotated downward, so that it cannot fall downward out of the pouring spout 12. The teeth 22, 23 and the ring segments 26, 27 now project downward from the pouring spout 12. In the residue emptying region 28, the self-opening sleeve 20, by contrast, does not project downward from the pouring spout 12, or at least does not project downward beyond the packaging wall. The residue emptying of the container is thereby facilitated.

(23) When the closure is opened for the first time, the driver 34 exerts on the driving cam 24 a force which is directed obliquely downward. As a result of this force transmission between driver 34 and driving cam 24, the downward movement of the self-opening sleeve 20 is aided. The here acting reaction forces are transmitted over the entire length of the base of the driver 34 to the cover face 31 of the cap 30, without generation of excessive stresses. All in all, an almost optimal force transmission is in this way ensured. As a result of the hook-like configuration of the driving cam 24, a radial swerving of the driver 34 in the inward direction is here prevented.

(24) For re-closure, the user places the cap 30 back onto the pouring spout 12 and screws the cap 30 back onto the pouring spout 12. The driver 34 here slides with its rear edge 342 over the slide face 242 of the driving cam 24 and is here deflected radially inward, so that the self-opening sleeve 20 remains in its lower opening position.

(25) In FIG. 8, a self-opening sleeve (cutting ring) according to a second illustrative embodiment is illustrated by way of example. Mutually corresponding parts are provided with the same reference symbols as in the embodiment of FIGS. 1 to 7. This embodiment is in particular suited to packagings which have no prepunched and overlaminated opening. In particular, the packaging can be made of a single-layered plastics wall. In this case, it is advantageous to provide just a single tooth 22. In this way, the opening forces are optimally concentrated on a single point. Apart from this, the closure of FIG. 8 is configured substantially the same as that of FIGS. 1 to 6.

(26) A self-opening sleeve (cutting ring) according to a third illustrative embodiment is represented by way of example in FIG. 9. Here three teeth 22, 23, 23 are present, the tips of which are spaced apart by respectively about 70. Otherwise, mutually corresponding parts are in turn provided with the same reference symbols as in the embodiment of FIGS. 1 to 7.

(27) Of course, a large number of modifications are possible without departing from the scope of the invention. It is in particular conceivable not to connect the cap by a threaded joint to the pouring spout, but, for example, to provide a bayonet-type connection in which the cap firstly, upon opening, performs a pure rotation and is subsequently pulled off axially. It is clear that such a variant has only a small influence on the cooperation of the driver with the driving cam. The shape of the tooth or teeth can also, of course, be chosen differently than in the present example. In addition, a (blunt) tooth-like hold-down device can be provided in order to bend back the cut-out segment of the packaging wall (flap) downward, into the inside of the packaging, so that this cutout does not impede the pouring out of the content of the packaging. Designs of this type are in principle known from the prior art. The pouring spout can be configured, instead of on a separate base element, essentially also in one piece with the packaging wall, or can form the upper end of a bottle neck. A large number of further modifications is possible.