Technical Field

The present invention relates to a tethered plastic screw stopper.

In the field of liquid packaging, it is very common to seal the aperture of a container with a stopper, usually made from plastic material. Such container is usually a plastic or glass bottle, filled with a liquid.

The stopper has a tubular shape closed at its top edge. The stopper comprises a closure shell attached to a tamper band through bridges. The bridges are distributed around the closure shell and the tamper band. Moreover, the bridges are made when molding the stopper or after through a cutting step.

Usually the bottle neck comprises outer fixation feature, such as thread(s) for screw type stopper or annular fixation rings for snap type stopper, to secure the stopper on the bottle neck.

As known, according to screw type stopper, the closure shell comprises inner thread(s) arranged inside side walls. The bottle neck fixation feature comprises outer thread(s). Such combination of outer and inner thread(s) allows the stopper to be screwed on a bottle neck to seal it and unscrewed for bottle entirely opening. According to another known embodiment, a snap type stopper comprises inner annular area and the bottle neck fixation feature comprises outer fixation ring, in order to slot in force the stopper on the bottle neck. Moreover, a snap type stopper comprises a closure shell with a movable sealing roof from a closure position to a part opening, and reversely. The roof may be separating upon opening or may be connected with the closure shell.

In a bottle sealing position of the stopper, the tamper band is secured around the bottle neck through inner tamper band retaining features or through the tamper band diameter being smaller than a diameter of a tamper evident ring of the bottle neck.

Usually, the closure shell and/or the roof is removable. During bottle opening, the bridges form a weakness line and are tom apart from the closure shell and/or the roof, so it is separated from the bottle. The weakness line is tom when user unscrews the closure shell of the stopper or when user lifts the roof by tilting.

There is a recycling risk with separable closure shell and/or roof as consumers may not always screw or snap back the closure shell and/or the roof onto the bottle neck once empty. The stopper may result to be heading to the trash bin or worse landfill and it is not good in view of the environmental considerations. A solution consists in linking the closure shell to the tamper band secured on the bottle neck, so the closure shell stays attached to the bottle after bottle opening. Such an attached stopper is so called a “tethered stopper”.

As described in US 9,010,555 a plastic screw cap comprises a peripheral strip between a tamper band and a closure shell. Such peripheral strip is linked at the tamper band through a bottom weakness line and at the closure shell through a top weakness line. The bottom weakness line and top weakness line are parallel and extend almost the entire periphery of the cap in order to manage a hinge or two hinges close together. When unscrewing the cap, the bottom weakness line and the top weakness lines tear apart but the two hinges hold the closure shell on the tamper band. The closure shell becomes unremovable and it toggles around the hinges beside of the cap secured on the bottle neck.

Moreover, the bottom and the top weakness lines are made of bridges, which tear apart when unscrewing the closure shell until they break. Especially the bridge plastic material has a specific thickness in order to undergo a plastic deformation until tearing and breaking.

Usually when fabricating a stopper, the top and bottom weakness lines are created when molding the stopper or through a further cutting or slitting step. So such known stopper has a problem of resistance of the strip, especially at its ends, where the strip is linked to the closure shell and to the tamper band. In particular, when pulling off the closure shell from the bottle neck, the top or bottom weakness line can spread beyond its extremities, tearing and breaking the strip ends. As a result, the strip ends can easily be broken and the closure shell is not linked anymore to the bottle neck.

Summary of Invention

An object of the present invention is to improve a tethered plastic screw stopper wherein its closure shell remains attached to its tamper band after bottle opening through at least a strip integrated into (e.g., formed within) the plastic material of the stopper between the tamper band and the closure shell through a bottom weakness line and a top weakness line. Each strip remains connected to the tamper band secured on the bottle neck through a least a bottom hinge managed into the bottom weakness line. Moreover, the opposite ends of each strip are directly linked to the closure shell through a junction point. Brief description of the Drawings

The invention can be better understood on reading the following description given merely by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic lateral view of a first embodiment of a tethered stopper according to the invention, in a closed position;

FIG. 2 is a diagrammatic cross section view of a detail of a first embodiment of a tethered stopper, in a closed position; and

FIG. 3 is a diagrammatic cross section view of a detail of a second embodiment of a tethered stopper, in a closed position.

Description of Embodiments

The invention relates to a tethered plastic screw stopper 1, for closing a bottle neck. The stopper 1 is integrally made of one plastic piece by a molding fabrication step. Other parts or elements of the stopper 1 can be further created into the entire plastic piece through a cutting or slitting step.

The stopper 1 is a screw type. It comprises inner fixation features, such as thread(s), designed to cooperate with outer complementary fixation features made on the bottle neck.

The stopper 1 comprises a closure shell 2 and underneath a tamper band 4. The tamper band 4 and the closure shell 2 are linked together.

The stopper 1 comprises a strip 6. According to a preferred embodiment, the stopper 1 comprises two strips 6. The two strips 6 are oppositely managed regarding a diameter of the stopper 1.

The strip 6 is linked at its top end to the closure shell 2.

The stopper 1 comprises a bottom weakness line 8 separably linked through bottom bridges to the top edge of the tamper band 4 and to the bottom edges of each strip 6 and of the closure shell 2.

The stopper 1 comprises a top weakness line 10 separably linked through top bridges to the bottom edges of the closure shell 2 and at least to the top edge of each strip 6.

So when unscrewing the closure shell 2, the bottom bridges and the top bridges are stretched until they break, the closure shell 2 remaining attached to each strip 6 through its top end, the strip 6 remaining attached at its opposite bottom end to the tamper band 4.

According to an embodiment, the stopper 1 comprises at least a hinge 12 managed into the bottom weakness line 8. Especially, the stopper 1 comprises two hinges 12, spaced apart through a hollow line or through an area of less thick material. Each hinge 12 links each strip 6 to the tamper band 4. Moreover, the top weakness line 10 is separably linked through the top bridges to the bottom edge of the closure shell 2 and to the top edge to each hinge 12.

According to an embodiment, the stopper 1 comprises at least an inner annular ring 14. Each inner annular ring 14 extends at least along a part of the length of at least a strip 6 and at least along the bottom or the top end of strip. Especially, each inner annular ring 14 extends at least along a part of the length of each strip 6. In other words, the inner annular ring 14 can continuously extend from one of its extremity to its opposite extremity, or being made of several segments.

According to an embodiment, each inner annular ring 14 extends along the entire length of each strip 6. So each inner annular ring 14 extends along each strip 6 and along one of its top end and/or its bottom end.

According to a preferred embodiment, each inner annular ring 14 extends along the entire inner periphery of the stopper 1. So the inner annular ring 14 extends along each strip 6, along the closure shell 2 and along the hinge 12.

According to an embodiment, an inner annular ring 14 extends along the bottom of the top weakness line 10. An example of a stopper 1 is shown in FIG 2, wherein only one inner annular ring 14 extends just under and along a part or the entire length of the top weakness line 10.

According to an embodiment, an inner annular ring 14 extends along the top of the bottom weakness line 8.

Accord to a preferred embodiment, such as shown in FIG 3, the stopper 1 comprises two inner annular rings 14 one extending along the top of the bottom weakness line 8 and the other extending along the bottom of the top weakness line 10. Such two inner annular ring 14 are also visible in two different dotted lines in the embodiment of FIG 1.

According to an embodiment, each inner annular ring 14 consists in a round offset extending inward relative to the inner wall of the stopper 1. Depending on its length, each inner annular ring 14 extends along a part or the entire length of the strip 6, along a part or the entire length of the tamper band 4, and along a part or the entire length of the closure shell 2. The round section shape of the inner annular ring 14 allows the strip top and bottom ends, where the inner annular ring 14 extends, to be more difficult to break, when opening and after opening.

So such inner annular ring(s) 14 extending inward reinforces the strip 6 and its junction with the closure shell 2 and the tamper band 4. Moreover, the annular ring 14 is invisible to the consumer, because it is managed inside the stopper 1, thus not deteriorating the external aspect of the stopper 1.