Closing means for bottles are known in the prior art. Glass bottles are generally sealed with a cork, plastic cap or a screw cap. Glass bottles containing beer or other carbonated beverages are generally sealed with a metal closure that is crimped around a groove that is a feature of the outer neck of the bottle. The commonplace form of this closure device is the crown cork, which is a pressed steel disk formed with a skirt of 21 tines.

Carbonated beverages may also be contained in plastic bottles, generally made from polypropylene (PP), polyethylene terapthalate (PET) or polyethylene naphtalate (PEN). The closure devices of these plastic bottles are usually screw caps, which are screwed on a threaded neck of the bottle.

It is a disadvantage of the closure devices of the prior art that specialised tools, such as bottle openers, are required to open a bottle that has been closed by a crown cork. There are some varieties of crown corks which are crimped on a threaded bottle, and may removed like a screw cap, but these crown corks are mainly limited to the French and North American markets. A further disadvantage of the closing devices of the prior art is that they must be tightly applied to prevent a loss of carbon dioxide upon prolonged storage at ambient temperature and also during pasteurisation. During pasteurisation the temperature of the bottle including the beverage will rise, so that a pressure build-up will take place within the bottle, which must be taken up by the closure. A requirement of the known closing devices is that they should be impervious to oxygen diffusing into the beverage, resulting in a degradation of the flavour of the beverage during prolonged storage of the bottle.

It is an object of the present invention to provide a simple closure device that inhibits diffusion of oxygen into the beverage, avoids loss of carbon dioxide upon prolonged storage and pasteurisation, and can easily be opened without the use of a special tool.

To this end, the glass container according to the present invention is characterised in that the cover member comprises on its inward side a flexible closing element that is

expandable in the neck connected with an operating means on the outward side of the cover member, the flexible closing element being operable by the operating means between a first position in which the flexible closing element is radially expanded towards the neck, and a second position in which the flexible closing element is spaced away from the neck. The flexible closing element may be of generally conical shape and in its first position sealingly engages the wall of the bottle neck and may be placed in a second position where the sealing element is spaced away from the wall of the neck.

Whenever the flexible closing element is contracted radially inwards, and away from the neck, a small clearance is created, causing release of the pressure that is normally present in the glass container whenever the contents of the container is a carbonated beverage. The closing element may then be easily removed from the neck.

Preferably the glass container according to claim 1 comprises a resilient clamping means, the flexible closing element being compressible by the resilient clamping means. By compression of the flexible element, this element expands in the neck of the bottle and seals off the opening. The advantage of this embodiment of the closure device is that high pressures in glass bottles, such as beer bottles, can be withstood, without loss of carbon dioxide from within the bottle.

Preferably the resilient clamping means and/or the flexible sealing element is a bi-stable element. Using a bi-stable element as resilient clamping means produces a rapid and distinct opening event, after an inversion point in passing from the expanded to the contracted state has been passed.

Preferably the cover member comprises of a central axis, a stopper member engaging a rim of the neck the flexible closing element and the resilient clamping means being placed on the axis, the clamping means in its first position compressing the flexible closing element against the stopper member, and being displaceable away from the stopper member by pressing down on the central axis. The stopper member that engages the rim of the neck seals the top of the glass bottle, so that no dirt is able to pass the closure mechanism that is placed under the stopper member inside the neck of the closed bottle.

Preferably the central shaft comprises a central stem having on the outward side of the stopper member a wide top end and on the inward side a broadened end part, the stopper member, the flexible closing element and the resilient clamping means being

with a central opening placed around the stem between the top end and the broadened end part. Such a construction provides a relatively simple and integrated closure device, which can be handled without separate parts that have to be disassembled to open the closure. The user can open the closure by pressing down on the top end. The pressure that is applied on the top end moves the axis into the glass container so that space is created for the resilient clamping means to snap into an expanded position in which the flexible element can expand along the axis resulting in a reduced diameter thereof. A clearance will thus appear between the flexible element and the neck of the bottle.

Preferably the resilient clamping means comprises a conical form with a substantially circular centre part, where a number of resilient fingers are attached, which provides an efficient bi-stable structure that can be placed in a first closed position and in a second opened position. It is further preferable that the flexible closing element comprises a cylindrical part and a conical end, which conical end lies against an internal surface of the resilient clamping means. The transfer of the pressure is very advantageous over the conical surface, because horizontal as well as vertical forces are transferred.

Preferably the flexible closing element comprises an elastic material. Once the material has been deformed, it will tend to revert to its original shape, so that no plastic deformation of the elastic material will occur.

Being able to withstand pressures to a maximum of 6-7 atmospheres, the bottle is preferably to be used for carbonated beverages, especially beer. Pressures that high occur while the beer is being pasteurised. During normal serving temperature the pressure will be around 1-1. 5 atmospheres.

An embodiment of the device according to the present invention will be explained in more detail with reference to the appended drawing, in which: Fig. 1 shows an exploded view of the closure device according to the present invention; and Fig. 2 shows a sideview of the closure device and the glass bottle according to the present invention.

Figure 1 shows an exploded view of the closure device 1 according to the present invention. The closure device 1 comprises a stopper disk 3, a flexible closing element 2 and a conical bi-stable element 8. The first side of the closure device 1 comprises a broadened top end, forming a push button 6 for applying a pressure on the axis 5. On the first side of the axis 5 the substantially flat stopper member 3 has been placed against the push button 6, in order to seal and cover the opening 7 of the neck of the bottle 4 and to prevent the closure device 1 from entering into the bottle 4. A flexible closing element in form of a piece of elastic material 8, has been placed against the stopper member 3. One side of the flexible closing element 8, the contact area to the stopper member 3, is flat. The other side of the flexible closing element 8, which is aligned along the axis 5, and which when in use as part of a closure will face towards the contents of the bottle, is of conical form. On the perimeter of the flexible closing element 8 ; several ribs 9 are formed to ensure and facilitate a gas-tight and liquid-tight contact with the neck 10 of the bottle 4.

The second side of the axis 5 shows a bi-stable element 2 in form of an umbrella- shaped metal plate or plastic plate. This plate has a central part 12, which central part comprises a hole, through which hole the axis 5 runs. Several fingers 11 protrude from the central part 12 of the resilient clamping means 2, and abut against the conical side of the flexible closing element 8.

On the second side of the axis 5, a broadened end part Y has been placed, to maintain the alignment of the stopper member 3, the resilient clamping means 2 and the flexible closing element 8.

By applying a pressure F on the push button 6 in a longitudinal direction of the axis 5, the clamping means 2 is moved from its first bi-stable state to its second bi-stable state in which the pressure clamping means 2 exerts on the flexible closing element 8 decreases, so that the flexible element 8 expands in the longitudinal direction of the axis 5 and contracts in the radial direction, so that a clearance (not shown) will appear between the flexible element 8 and the neck of the bottle. By creating such a clearance, the pressure in de bottle 4, caused by the carbon dioxide of the carbonated drinks in the bottle, is released, allowing the closure device to be easily removed.