TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a closure for a container, and more specifically to a closure that remains attached to the container after opening.

BACKGROUND ART

[0002] A plastic closure designed to remain attached to the container after opening is known from W02021/021095 Al. The closure is made in one piece and comprises a lid and a safety ring projecting from the lid. The safety ring is permanently connected to the lid by a first and a second tethers. A first incision line and a second incision line delineate the safety ring and the tethers. Frangible bridges are provided along the first and second incision lines and designed to break when the lid is opened.

[0003] Another tethered closure is disclosed in W02021116468A1, which includes two separation lines which delineate together two parallel tethers between an annular skirt of the main body of the closure and a safety ring. Each of the separation lines is provided with frangible bridges in the region of the tethers, which are broken when the annular skirt is moved relative to the safety ring.

[0004] In both prior arts, the frangible bridges are distributed along the two incision or separation lines, both in regions where the two lines have no overlap and in regions with overlap, which delineate the tethers. However, the tethers are substantially less rigid than the surrounding ring and annular skirt and it may prove challenging to design the bridges so that they will break when necessary to allow the tethers to fold in a controlled manner when the annular skirt is moved away from the safety ring.

SUMMARY OF THE INVENTION

[0005] The invention aims to provide a tethered closure which has frangible bridges distributed over its circumference but allows a controlled folding of the tethers during opening. [0006] According to a first aspect of the invention, there is provided a closure for a container, comprising a one-piece body, the one-piece body comprising an annular wall the annular wall comprising an annular skirt, a safety ring as well as a first and a second tethers permanently connecting the annular skirt to the safety ring, the safety ring defining a reference axis of the one-piece body, the one piece body having a first incision line and a second incision line, which do not converge with one another. The first incision line has a first set of one or more line segments, which at least partly overlaps in a circumferential direction of the closure a first set of one more line segments of the second incision line, whereby the first set of one or more line segments of the first incision line and the first set of one or more line segments of the second incision line delineate the first tether. The first incision line has a second set of one or more line segments, which at least partly overlaps in the circumferential direction a second set of one or more line segments of the second incision line, whereby the second set of one or more line segments of the first incision line and the second set of one or more line segments of the second incision line delineate the second tether. The first incision line has one or more intermediate line segments, which do not belong to the first or second sets of one or more line segments of the first incision line and do not overlap the second incision line. The second incision line has one or more intermediate line segments, which do not belong to the first or second sets of one or more line segments of the second incision line and do not overlap the first incision line. The one or more intermediate line segments of the first incision line include one or more frangible line segments with one or more frangible bridges. The first and second sets of one or more line segments of the first incision line and of the second incision line extend right through the annular wall without frangible bridges. The one or more intermediate line segments of the second incision line include one or more frangible line segments each provided with one or more frangible bridges between the annular skirt and the safety ring.

[0007] The frangible bridges are preferably designed as to be clearly visible in their broken state after the closure has been opened for the first time and reclosed, so as to provide an indication of the first opening of the closure. The frangible bridges directly link the annular skirt to the safety ring, which are both rigid portions of the body. This ensures a controlled breaking of the frangible bridges when the annular skirt is moved away from safety ring. They are distributed along both incision lines, i.e. more evenly around the perimeter of the annular wall than if only the first incision line were provided with frangible bridges. This ensures that no part of the annular skirt or safety ring protrudes outwardly when the closure is assembled on the container. The frangible bridges are located in intermediate regions of the first and second broken incision lines, at a distance from the first and second tethers, so that they do not impede the folding of the tethers during the opening.

[0008] In an embodiment, the one or more frangible bridges of the one or more intermediate line segment of the second incision line preferably have a width or widths that is/are smaller than the width or widths of the one or more frangible bridges of the one or more intermediate line segment of the first incision line.

[0009] In a preferred embodiment, each of the frangible line segments of the first incision line and of the second incision line lies in an associated reference plane perpendicular to the reference axis. This makes it possible to cut the frangible intermediate line segments with blades which extend perpendicularly to the reference axis and are less subject to stress and wear.

[0010] In a preferred embodiment, the one or more intermediate line segments of the first incision line are located in a common first reference plane perpendicular to the reference axis. Preferably, at least one of the frangible line segments of the second incision line lies in the first reference plane. The first reference plane defines a main separation plane between the annular skirt and the safety ring. If necessary, at least one of the frangible line segments of the second incision line lies in a second reference plane perpendicular to the reference axis, located at a distance from the first reference plane.

[0011] In an embodiment, the first set of one or more line segments of the first incision line extends from a first end of the first incision line in the circumferential direction towards a second end of the first incision line, and the second set of one or more line segments of the first incision line extends from the second end of the first incision line in a direction opposed to the circumferential direction towards the first end of the first incision line. In other words, the first set of line segments of the first incision line includes the first end of the first incision line, while the second set of line segment of the first incision includes the second end of the first incision line. Preferably, the first incision line extends over an angle greater than 180° and less than 270° in the circumferential direction about the axis of reference from the first end of the first incision line to the second end of the first incision line. The first incision line delineates a separation between a front portion of the annular skirt and a front portion of the safety ring.

[0012] In an embodiment, the first set of one or more line segments of the second incision line extends from a first end of the second incision line in the direction opposed to the circumferential direction towards a second end of the second incision line, and the second set of one or more line segments of the second incision line extends from the second end of the second incision line in the circumferential direction towards the first end of the second incision line. In other words, the first set of line segments of the second incision line includes the first end of the second incision line, while the second set of line segment of the second incision includes the second end of the second incision line. Preferably, the second incision line extends over an angle less than 180° in the direction opposite to the circumferential direction about the axis of reference from the first end of the second incision line to the second end of the second incision line. The second incision line delineates a separation between a rear portion of the annular skirt and a rear portion of the safety ring, between the first and second tethers.

[0013] In one embodiment, the safety ring is provided with at least one tab protruding towards the annular skirt, the annular skirt is provided with at least one tab protruding towards the safety ring, and at least one of the tabs protruding from the annular skirt or from the safety ring is delineated by a set of line segments of the second incision line, which includes at least one of the one or more frangible line segments from the one or more intermediate line segments of the second incision line. Preferably, both tabs are delineated by a set of line segments which includes one frangible line segment. Each frangible line segment ensures that once the closure is assembled on the container neck in the closed position, the associated tab does not protrude radially outwards. In some instances, one frangible line segment on one of the two tabs may be sufficient. [0014] In a preferred embodiment, the annular skirt is provided with an inner thread defining an unscrewing direction of rotation about the reference axis, which is identical to the circumferential direction, and each of the first and second tethers extends in the unscrewing direction from a connection area with the annular skirt to a connection area with the safety ring. When the closure is unscrewed from the container neck for the first time, the safety ring is prevented from following the upward motion of the annular skirt , so that the frangible bridges break by tensile force. The subsequent upward motion of the annular skirt causes the tethers to bend, which in turn causes the annular skirt to rotate faster than the safety ring rotating about the revolution axis.

[0015] The incision lines are obtained by a cutting process with blades that preferably do not remove material from the closure. In a preferred embodiment, at least some, and preferably all, of the line segments of the first of second sets of one or more line segments and/or of the intermediate line segments of the first and/or second incision lines have adjoining incision side walls. Adjoining incision side walls contribute to the sealing of the closure.

[0016] In one embodiment, the body further comprises a top wall from which the annular skirt projects to form a lid of the closure. The tethered connection is used as main hinge to open and close the lid.

[0017] In another embodiment, the annular wall is part of a base of the closure, which further comprises a lid hinged to the base. Access to the contents of the container is usually gained by opening the lid by means of the hinge, and more exceptionally, for example if the container is to be completely emptied, by separating the annular skirt from the safety ring. In one embodiment, the lid and the base are parts of the one-piece body.

[0018] In one embodiment, the safety ring is provided with hook-shape resilient portions projecting towards the reference axis. When the closure is engaged with the neck of a container, the resilient hook-shaped portions snap under an annular retention bead formed on the neck of the container to prevent the safety ring from being torn off. [0019] The length of the tethers is preferably chosen so as to enable a flipping movement of the annular skirt relative to the safety ring. In one embodiment, the first sets of one or more line segments of the first and second incision lines overlap each other over an angle of more than 30° and less than 90° about the rotation axis and the second sets of one or more line segments of the first and second incision lines overlap each other over an angle of more than 5°, preferably more than 10° and less than 60°, preferably less than 30° about the rotation axis.

[0020] In one embodiment, each of the first and second incision lines is a broken line which consists of a series of consecutive line segments, each lying in an associated blade plane. Such broken incision lines are obtained by cutting a side wall of the closure with blades with blade segments that are essentially flat and therefore much easier to manufacture than curved blades.

[0021] Obviously, the above-mentioned embodiments can be combined.

[0022] According to another aspect of the invention, there is provided a closure for a container, comprising a one-piece body, the one-piece body comprising an annular wall the annular wall comprising an annular skirt, a safety ring as well as a first and a second tethers permanently connecting the annular skirt to the safety ring, the safety ring defining a reference axis of the one-piece body, the one piece body having a first incision line and a second incision line, which do not converge with one another. The first incision line has a first set of one or more line segments, which at least partly overlaps in a circumferential direction of the closure a first set of one more line segments of the second incision line, whereby the first set of one or more line segments of the first incision line and the first set of one or more line segments of the second incision line delineate the first tether. The first incision line has a second set of one or more line segments, which at least partly overlaps in the circumferential direction a second set of one or more line segments of the second incision line, whereby the second set of one or more line segments of the first incision line and the second set of one or more line segments of the second incision line delineate the second tether. The first incision line has one or more intermediate line segments, which do not belong to the first or second sets of one or more line segments of the first incision line and do not overlap the second incision line. The second incision line has one or more intermediate line segments, which do not belong to the first or second sets of one or more line segments of the second incision line and do not overlap the first incision line. The one or more intermediate line segments of the first incision line include one or more frangible line segments with one or more frangible bridges. The one or more intermediate line segments of the second incision line include one or more frangible line segments each provided with one or more frangible bridges between the annular skirt and the safety ring. The safety ring is provided with at least one tab protruding towards the annular skirt, the annular skirt is provided with at least one tab protruding towards the safety ring, and at least one of the tabs protruding from the annular skirt or from the safety ring is delineated by a set of line segments of the second incision line, which includes at least one of the one or more frangible line segments from the one or more intermediate line segments of the second incision line. The closure according to this aspect of the invention can include at least some of the features of the closure according to the first aspect of the invention.

BRIEF DESCRIPTION OF THE FIGURES

[0023] Other advantages and features of the invention will then become more clearly apparent from the following description of specific embodiments of the invention given as non-limiting examples only and represented in the accompanying drawings in which:

- Figure 1 is a rear view of a closure in accordance with a first embodiment of the invention, in a closed position;

- Figure 2 is a side view of the closure of figure 1 in the closed position;

- Figure 3 is a cross-section through the plane 111-111 of figure 2;

- Figure 4 is a top view of the closure of figure 1 in an open position;

- Figure 5 is a cross-section though the plane V-V of figure 4;

- Figure 6 is an isometric view of the closure of figure 1 in the closed position; Figure 7 is a rear view of a closure in accordance with a second embodiment of the invention, in a closed position;

- Figure 8 is rear view of a closure in accordance with a third embodiment of the invention, in a closed position;

- Figure 9 is a side view of the closure of figure 8 in the closed position.

[0024] Corresponding reference numerals refer to the same or corresponding parts in each of the figures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0025] With reference to Figures 1 to 6, a plastic closure 10 for a container consists of a one-piece body 12 comprising a top wall 14 and an annular side wall 16, which projects from a periphery of the top wall 14 in an axial direction parallel to a reference axis 100 of the closure 10.

[0026] The annular side wall 16 forms a safety ring 18 at its free end axially opposed to the top wall 14, an annular skirt 20 between the top wall 14 and the safety ring 18 as well as a first and a second tethers 22, 24 for permanently connecting the annular skirt 20 to the safety ring 18. The top wall 14 and annular skirt 20 form a lid 25 of the closure 10.

[0027] The annular skirt 20 is provided with an inner thread 26 depicted in figure 3, which defines an unscrewing direction of rotation 200 about the reference axis 100, which will also be referred to as the circumferential direction of the closure 10. The safety ring 18 may be provided with one or more hook-shaped resilient portions 28 projecting radially towards the reference axis 100 to snap under an annular bead of a container neck and secure the closure 10 to the container.

[0028] The tethers 22, 24 and the safety ring 18 are delineated by a first incision line 30 and a second incision line 40, which have no intersection. The first incision line 30 extends over an angle, which is preferably greater than 180°, e.g. greater than 220° about the axis of refence 100 between a first end 31 and a second end 32 of the first incision line 30 while the second incision line 40 extends over an angle, which may be greater than 50° and less than 180° about the axis of refence 100 between a first end 41 and a second end 42 of the second incision line 40.

[0029] The first tether 22 is delineated by a first set of one or more line segments 33 of the first incision line 30 and a first set of one or more line segments 43, 44 of the second incision line 40, which at least partially overlaps with the first set of one or more line segments 33 of the first incision line 30 in the unscrewing direction of rotation 200. The first set of line segments 33 of the first incision line consists of a terminal segment, which lies in a first reference plane Pl perpendicular to the reference axis 100 and extends from the first end 31 of the first incision line 30 in the unscrewing direction 200 towards the second end 32 of the first incision line 30, while the first set of line segments of the second incision line 40 consists of a terminal segment 43, which lies in a second reference plane P2 parallel to and distant from the first reference plane Pl and extends from the first end 41 of the second incision line 40 in the direction opposed to the unscrewing direction 200, and of an adjacent line segment 44. As a result, the first tether extends 22 in the unscrewing direction 200 from a connection area 221 with the annular skirt 20 to a connection area 222 with the safety ring 18.

[0030] The second tether 24 is delineated by a second set of one or more line segments 35, 36 of the first incision line 30 and a second set of one or more line segments 48, 49 of the second incision line, which at least partially overlap with the second set of line segments 35, 36 of the first incision line 30 in the unscrewing direction of rotation 200. More specifically, the second set of line segments of the first incision line 30 consists of a terminal segment 36, which lies in the second reference plane P2 and extends from the second end 32 of the first incision line 30 in the direction of rotation opposed to the unscrewing direction 200 towards the first end 31 of the first incision line 30, and of an adjacent line segment 35, while the second set of line segments of the second incision line 40 consists of a terminal segment 49, which lies in the first reference plane Pl and extends from the second end 42 of the second incision line 40 in the unscrewing direction 200 towards the first end 41 of the second incision line 40, and of an adjacent line segment 48. Hence, the second tether 24 extends in the unscrewing direction 200 from a connection area 241 with the annular skirt 20 to a connection area 242 with the safety ring 18.

[0031] As illustrated in figure 6 the length of the tethers 22, 24 in the circumferential direction 200 is defined by the overlap between the first and second incision lines 30, 40. The length of the first and second tethers 22, 24 is preferably the same, which means that an overlap angle 300 between the first set of one or more line segments 33 of the first incision line 30 and the first set of one or more line segments 43, 44 of the second incision line measured about the reference axis 100 is equal to an overlap angle 400 between the second set of one or more line segments 35, 36 of the first incision line 30 and the second set of one or more line segments 48, 49 of the second incision line 40 measured about the reference axis 100. This overlap angle is preferably greater than 5°, more preferably greater than 10°, and preferably less than 60°, more preferably less than 30°.

[0032] The first incision line 30 further comprises a set of one or more intermediate line sections 34, which do not overlap with the second incision line 40 and connect the first set of line sections 33 of first incision line 30 with the second set of line sections 35, 36 of the first incision line 30. These one or more intermediate line sections 34 delineate a separation between a front part of the annular skirt 20 and the safety ring 18. In the present embodiment, the set of one or more intermediate sections consists of one line section 34 only, which lies in the first reference plane Pl, but other configurations are also possible.

[0033] The second incision line 40 further comprises a set of one or more intermediate line section 45, 46, 47, which do not overlap with the first incision line 30 and connect the first set of line sections 43, 44 of second incision line 40 with the second set of line sections 48, 49 of the second incision line 40. These intermediate line sections 45, 46, 47 delineate a separation between a rear or hinged part of the annular skirt 20 and the safety ring 18. In the present embodiment, the intermediate line sections include at least one intermediate line section 47 which lies in a third reference plane P3 perpendicular to the reference axis 100 and one intermediate line section 45 which lies in a fourth reference plane P4 perpendicular to the reference axis, to form a tab 50 of the annular skirt, which lies between the first and second tethers 22, 24 and protrudes towards the safety ring 18 and an adjacent tab 52 of the safety ring 18, which protrudes towards the annular skirt 20 and lies between the tab 50 of the annular skirt 20 and the first tether 22. The tabs 50, 52 preferably have a trapezoidal shape, which converges towards their free end, i.e. towards the third and fourth reference planes P3, P4, respectively.

[0034] The set of intermediate line sections 34 of the first incision line is provided with frangible bridges 54, which link the front part of the annular skirt 20 to the safety ring 18 before the first opening of the closure and break when the closure is unscrewed. The set of intermediate line sections 45, 46, 47 of the second incision line 40 is provided with frangible bridges 56, which link the rear part of the annular skirt 20 to the safety ring 18 before the first opening of the closure and break when the closure is unscrewed. All frangible bridges 54, 56 cross line sections 34, 47, 45 that lie in a plane perpendicular Pl, P3, P4 to the reference axis. The frangible bridges 56 have a width, measured in the circumferential direction, which is preferably smaller than a width of the frangible 54.

[0035] Remarkably, the first and second sets line sections 33, 43, 44, 35, 36, 49, 48 of the first and second incision lines 30, 40, which delineate the first and second tether 22, 24, are without frangible bridges.

[0036] When the closure 10 is moved in the unscrewing direction 200 of rotation relative to the container, the lid 25 and the safety ring 18 move away from each other in the axial direction and the frangible bridges 54, 56 break without difficulty, because they link parts of the safety ring 18 and of the lid 25 which are rigid, i.e. more rigid than the tethers 22, 24. As the lid 25 continues to rotate and to move away from the safety ring 18 in the axial direction, the tethers 22, 24 unfold, which causes the safety ring 18 to rotate relative to the lid 25 in the direction opposed to the unscrewing direction 200. Once the lid 25 is unscrewed, the user can flip the lid 25 relative to the safety ring 18 about an instantaneous hinge axis which at each instant lies in a plane perpendicular to the reference axis 100 ata distance from the reference axis 100. Once the lid 25 has reached the opened position in figures 4 and 5, the tab 50 of the annular skirt 20 bears against the tab 52 of the safety ring 18 to maintain the closure in the opened position. [0037] The length and elasticity of the first and second tethers 22, 24 are such that the first and second tethers 22, 24 are stretched when the lid 25 reaches the flipped position against the safety ring, thereby providing a stable open position.

[0038] In this particular embodiment, the second and third reference plane P2, P3 are coplanar, but more generally, the third reference plane P3 can be located anywhere between the first reference plane Pl and the second reference plane P2 or closer to the second reference plane P2 than to the first reference plane Pl so that the length and position of the tab 50 of the annular skirt 20 can be adapted. Similarly, the fourth reference plane P4 in this particular embodiment is coplanar with the first reference plane Pl but could be located anywhere at a distance from the third reference plane P3 between the third reference plane P3 and the first reference plane Pl or closer to the first reference plane Pl than to the third reference plane P3, so that the length and position of the tab 52 of the safety ring 18 can be adapted.

[0039] Each of the first and second incision lines 30, 40 consists of a series of consecutive line segments. The incision lines 30, 40 are obtained by blades cutting partially or totally through the side wall 16 of the closure 10, preferably without removing plastic material, and the line segments 33 to 36 and 43 to 49 have adjoining incision walls. A suitable cutting process described in W021021095. The closures are mounted on spindles so that their reference axis 100 is coaxial with the rotation axis of the spindles. They are rolled along blades in order to produce the incision lines 30, 40. Each line section of each incision line 30, 40 is associated with a blade segment. The frangible bridges 54, 56 are formed by dents in the blade sections. The blades can either cut right through the side wall 16 of the closure 10 that forms the annular skirt 20 and the safety ring 18, which is the preferred option, or leave a frangible film of material at the bottom of the line segments. The blade segments are preferably flat rather than curved, and each of the two incision lines 30, 40 can be described as a broken line, i.e. a line made of a series of consecutive “rectilinear” line segments, i.e. line segments which lie each in an associated blade plane.

[0040] The embodiment of figure 7 differs from the embodiment of figures 1 to 6 in that the third reference plane P3 is closer to the second reference plane P2 than to the first reference plane Pl and in that the fourth reference plane P4 is between the first and second reference planes Pl, P2. Other locations of the planes P3 and P4 are also possible.

[0041] The embodiment of figures 8 and 9 differs from the embodiment of figures

1 to 5 in that the closure comprises a lid 25 hinged to a base 125 which has an annular wall 16 with incision lines 30, 40, which delineate an annular skirt 20, a safety ring 18 and two tethers 22, 24.