FIELD OF THE INVENTION This invention relates to an air inlet valve and system for closed drinking vessels whereby any vacuum that may tend to develop in the interior of a closed drinking vessel is countered by allowing air to enter the drinking vessel by way of such inlet valve.

BACKGROUND TO THE INVENTION It is commonly known that air must be allowed to enter a closed vessel containing drinking liquids of any description, typically water or an energy drink, in order that a continued supply of liquid may be withdrawn from the closed vessel.

In the case of larger installations such as so-called drinking fountains using large inverted bottles typically containing purified or spring water an air inlet system is invariably provided.

In the case of smaller applications, such as personal sizes of drinking vessels, the problem of allowing air to enter to break any vacuum tending to form, has been addressed in a number of different ways in different applications.

In the case of infant feeding bottles US patents 4,723,668; 4,928,836; and 5,692,67, for example, described air inlet valves for this purpose. In each case the air inlet valve consists of different components that require structural modifications to the infant feeding bottles and must of necessity be relatively costly due to their structure. Also, their reliability not to leak when in a normal

upright orientation must be questioned, as far as applicant understands the proposals.

US patent 2,107,442, on the other hand, proposes an air inlet and outlet assembly that fits into the neck of a bottle.

In addition, numerous different proposals have been put forward of drinking vessels having open mouths, generally an open top to the vessel, of relatively large size and air inlet valves have been provided in lids that seal onto the periphery of the open mouths. Examples of these are US patents RE 3 7,016; 5,465,866; and 5,706,973; and 5,890,620; 6,102,245; and 6,305,570. All of these are relatively expensive or complicated, or both and the configuration of at least most of them is not particularly appropriate to drinking vessels in the nature of common blow moulded bottles that, for example, sportsmen or other persons taking part in activities out of doors may use.

There are, furthermore, numerous different one-way valves that have been proposed and, for the most part, these also generally consist of a plurality of parts and are also generally relatively costly.

OBJECT OF THE INVENTION It is an object of this invention to provide an air inlet valve that is simple in construction, easy to manufacture, and that can be applied to a drinking vessel of the nature of a bottle easily and effectively.

SUMMARY OF THE INVENTION In accordance with one aspect of the invention there is provided a one-way valve comprising a tubular body having a bore that is open at an inlet end and closed at an outlet end, the body being made of a resiliently deformable

material, an outwardly directed head at or towards the inlet end and a neck region adjacent the head that is adapted to cooperate with the periphery of an aperture in a vessel wall through which the body extends to form a seal therewith; and wherein the wall of the body converges towards the outlet end to terminate in a transverse closure wall having a slit therein communicating between the outside and the bore and adapted to allow the passage of fluid from the interior of the bore to the outside thereof but not in the reverse direction.

Further features of this aspect of the invention provide for an integral circumferentially extending locating ridge to be spaced from the head such that the locating ridge, body, and head form said neck; for the one-way valve to be a single one piece moulding of elastomeric material; for the valves to be moulded, conveniently by an injection moulding process, with a closed outlet end that is subsequently cut to form the slit ; and for the wall of the body to converge towards said outlet end equally from two diametrically opposite sides to terminate in a diametrically extending narrow closure wall at the outlet end of the valve.

In accordance with a second aspect of the invention there is provided a method of providing a prefabricated operatively closed drinking vessel, typically a blow moulded beverage bottle, with an air inlet, the method comprising the steps of forming an aperture in the wall of the drinking vessel, and introducing a valve as defined above with its inlet end on the outside of the drinking vessel and the outlet end on the inside of the drinking vessel.

Further features of this aspect of the invention provide for the valve to be introduced into the aperture by pulling it from the inside using a suitable tool so as to cause the elastomeric body to reduce in effective diameter so as to enable the locating ridge to pass through the aperture and the periphery of the aperture to become lodged sealingly in the said neck of the valve.

The invention still further provides a punch assembly having a circular punch and cooperating die or anvil each of which is carried at or towards an end of an operating arm and wherein at least one of the arms is specially shaped or configured so as to enable a hole to be punched in the shoulder or side wall of a plastics bottle with the one arm entering by way of a mouth to the bottle.

In order that the above and other features of the invention may be more fully understood, one embodiment of the invention and its application to blow moulded beverage bottles will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:- Figure 1 is a side elevation of one embodiment of inlet valve according to the invention; Figure 2 is a front elevation thereof; Figure 3 is a sectional side elevation corresponding to Figure 1 with the moulded valve body not yet provided with the functional slit ; Figure 4 is a sectional front elevation corresponding to Figure 2 and showing the one face of the slit ; Figure 5 is a sectional side elevation similar to Figure 3 and showing the slit and the cooperation of the body with the periphery of an aperture in a drinking vessel wall ;

Figure 6 is an isometric view of the inlet valve from the outlet end thereof; Figure 7 illustrates a beverage bottle provided with a hole for receiving an inlet valve according to this embodiment of the invention ; Figure 8 is an elevation of the beverage bottle rotated about its axis through 90 degrees and with a portion shown in section illustrating the inlet valve in position; and, Figure 9 is an elevation of a manually operable punch assembly for use in forming holes in beverage bottle walls.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS In the embodiment of the invention illustrated in Figures 1 to 6 an inlet valve, generally indicated by numeral (1), is made as a single piece injection moulded body of elastomeric material, typically a food grade of rubber or other elastomeric material. In tests conducted to date a natural rubber based compound designed to conform to the German BGA standards was used effectively. The hardness of the rubber should be selected so that the valve functions properly, in use, and the body seals properly to the periphery of an aperture through the wall of a drinking vessel, in use. It is envisaged that a hardness of between 50 and 60 Shore A will operate effectively and successful tests have been conducted on a rubber having a Shore A hardness of 55.

The body is basically tubular and of circular shape in cross-section and has a bore (2) having an inlet end (3) that is open. The other end of the bore tapers towards a narrow diametrically extending closure wall (4) and the body thus assumes a typical chisel shape. From the outside the body is thus of

generally right circular cylindrical shape with two diametrically opposite flat inclined faces (5) converging symmetrically to define the diametrically extending closure wall (4).

Moulding of the body takes place with the diametrically extending closure wall imperforate, as illustrated in Figure 3, and after moulding, a slit (6) is cut through the end wall to communicate between the bore and the outlet end of the valve. The two faces of the slit thus form the valve closure seat and, by virtue of the manner in which the slit is formed, the two faces will meet perfectly one with the other, and with the correct selection of elastomeric material, the two faces will form an effective closure to any fluid tending to enter the outlet end of the bore. Fluid pressure acting on the two flat convergent faces (5) will maintain the valve in a closed condition in the event that increased pressure on the outlet end of the valve occurs. On the other hand, in the event that decreased pressure exists outside of the slit at the outlet end of the valve the faces of the slit will part easily to allow fluid to flow from the inlet end and out of the outlet end of the valve.

In order to mount the valve in an aperture in a wall of a drinking vessel, typically a blow moulded beverage bottle or the like, the body has an integral head (7) at its inlet end and a narrow neck (8) formed between the head and a circumferentially extending locating ridge (9) also formed integral with the body. The neck is dimensioned to accommodate the thickness of a wall (10) of a drinking vessel as shown in Figure 5. This happens with the elastomeric body in a somewhat stressed elastic state so that effective sealing is achieved with the periphery of the aperture.

The valve described above can be installed in the wall of a container of any description either at the factory level or at a level closer to the end user, or even by the end user.

As an example, there is illustrated in Figures 7 and 8, a typical blow moulded plastics beverage bottle (11) to which a valve described above is to be fitted.

It will be quite clear that a hole could be made at factory level in the production of the beverage bottles but in this embodiment of the invention there is described the retrofitting of such valves to existing bottles.

In order to form a hole, there may be provided a punch assembly as illustrated in Figure 9 and generally indicated by numeral (12), to enable holes to be formed manually in such bottles. The punch assembly has a circular punch (13) mounted on one arm (14) of a pair of crossed pivotally attached levers (15) and a cooperating anvil (16) carried by an arm (17) of the other lever (15).

As provided by this invention the one arm, in this case the arm (17) carrying the anvil (16), is shaped so that it can pass through the mouth and neck (18) of the beverage bottle ; around the shoulder (19); and enable the anvil to be orientated approximately flush with the inside of the side wall (20) of the bottle. A hole (21) can be formed simply by forcing the levers together at the handle ends (22) thereof.

The diameter of the holes will generally be slightly less than the outer diameter of the neck of the valve body and the valve is fitted to the aperture by introducing the tapered end into the aperture and pulling the body from the inside using a pair of long nose pliers or any other gripping device to enable the valve to be pulled into the hole. In so doing the valve body stretches longitudinally and thus decreases in outer diameter to pass through the hole and with a bit of manipulation, the locating ridge (19) is pulled through the hole so that the periphery of the hole and thickness of the wall becomes located in the neck of the valve body between the head and the locating ridge. A highly effective seal is achieved in this manner.

It has been found that a valve manufactured and installed as described above operates highly effectively in that as the contents of, for example, the beverage bottle, are consumed, air enters substantially freely through the valve thereby avoiding the formation of any vacuum and also avoiding any interruption in the consumption of liquid from the beverage bottle.

It will be understood that numerous variations may be made to the embodiment of the invention described above without departing from the scope hereof. In particular, the exact configuration of the valve can be changed fairly widely the most important feature being that it is a one part elastomeric moulding that has the valve closure means formed integral with it. Also, the way in which the holes are formed in drinking vessels, be they beverage bottles or other vessels, can be varied widely and the holes may be formed at factory level in any suitable way.