Airtight container cap

Abstract

An airtight container cap which comprises a ring-nut provided, on its side surface, with at least one window or slot, and on its upper surface with a circular hole, a stopper and a gasket of elastic material, said stopper being removably engagable with said ring-nut and said elastic gasket, with the gasket disposed inside the ring-nut in a position corresponding to the window.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved container cap having an airtight lock, particularly for glass jars suited for the preservation of products contained therein, either under vacuum, or at atmospheric pressure.

In general such jars are used for the preservation of foodstuffs.

2. Description of the Prior Art

Airtight container caps are, of course, known in the art. For example, it is known to use caps which are pressed onto a lip or rim provided on the neck of a jar, after interposing an elastic sealing gasket between such lip or rim and the cap, which caps are maintained in a sealing position by means of metal hook locking devices, spring clamp lockings or the like.

To open a container sealed with such a cap, it is necessary to simply unfasten the locking device when the container is under atmospheric pressure. In contrast, when the container has been sealed under pressure, it is necessary to unfasten the metal locking device and subsequently to deform the elastic sealing gasket, generally by pulling on a small tongue, with which the gasket is provided for this purpose, in order to equalize the inside pressure of the container with the outside pressure, by allowing air to flow into the container.

The airtight seal provided by such caps in the case of preservation under atmospheric pressure leaves much to be desired, since the pressure is not uniformly distributed over the entire elastic gasket.

Italian Pat. No. 766,313 discloses an airtight container cap capable of achieving a good seal, said cap comprising a metal ring-nut, and a glass plug or stopper with a gasket of elastic material disposed therebetween.

These three component elements, of a particular shape, are associated with each other in a removable way. The gasket has peripheral tangs which engage a groove provided on the inner side of the metal ring-nut, and the glass stopper is provided with teeth.

With this type of locking cap, if the inside of the container is under atmospheric pressure, the opening of the container itself is achieved by simply unscrewing the ring-nut from the neck of the container. In this operation, of course, the glass stopper remains integral with the metal ring-nut as a result of the gripping action of the gasket tangs which hold the stopper constrained to the ring-nut itself.

If, on the contrary, the inside of the container is at a lower pressure than atmospheric pressure, that is, in the case of products preserved under vacuum, the opening of the container causes a separation or disassociation of the glass stopper from the metal ring-nut.

In fact, in such a case, in order to open the container, the following procedure must be followed.

The metal ring-nut must first be unscrewed from the neck of the container. By this step the ring-nut is removed, it being disengaged from the tangs of the sealing gasket, while the glass stopper and the gasket itself remain adhering to the opening of the container as a result of the outer atmospheric pressure acting on the stopper.

In order to remove the stopper it is necessary to pull at one of the gasket tangs thereby deforming the gasket and causing an inflow of air into the interior of the jar so as to bring the inner pressure into equilibrium with the outside pressure. Once a balance between the inside and outside pressure has been established, the stopper with the gasket are easily removed.

It is quite evident that with this type of cap the opening of a container sealed under vacuum results in a separation of the metal ring-nut from the glass stopper and from the sealing gasket with considerable practical drawbacks for the user who is compelled to reassemble the component elements of the cap itself.

Moreover, this type of cap requires a special configuration of the metal ring-nut and, in particular, of the glass stopper and the elastic sealing gasket.

SUMMARY OF THE INVENTION

According to the invention, there is provided a cap for the airtight closure of a container used for the preservation of products both at atmospheric pressure and under vacuum, which cap eliminates the above indicated drawbacks. Moreover, the cap provided by the intervention is completely hermetic. In addition, the cap according to the invention is such that, when opening the container, it is not necessary to disassemble the cap into its component elements whether the container is at atmospheric pressure or under vacuum.

Finally, the cap according to the invention is made up of component elements having a simple shape.

The airtight container cap according to the invention comprises a ring-nut provided, on its side surface, with at least one window or slot, a stopper and a gasket of elastic material, said stopper being removably engagable with said ring-nut and said elastic gasket, with the gasket disposed inside the ring-nut in a position corresponding to the window.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows in schematic form, an axonometric view of a glass jar having a sealing cap according to the invention, with its individual component elements shown in an exploded view;

FIG. 2 represents the component elements of FIG. 1 in front view; and

FIG. 3 represents in schematic form the glass jar of the preceding figures, sealed by the cap of the invention partially in section.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention will now be described in more detail in conjunction with the attached drawing.

Referring now to the drawing, wherein like reference numerals refer to like parts, the airtight cap comprises (FIG. 1) a ring-nut 1 made, for example, of plastic material and provided with an upper circular hole 2 and a window or slot 3 on the side surface thereof. Ring-nut 1 is provided with an internal female thread 4 for engagement with a complementary male thread 5 provided in the neck 6 of glass jar 7.

Of course, both the ring-nut as well as the jar neck, instead of being respectively provided with female and male threads, may have any other equivalent and known screwing or locking system, such as, for instance, a bayonet lock or a system of segments and the like.

Mounted within ring-nut 1, is glass stopper 8 which is removably engagable therewith. Removable engagement of glass stopper 8 with ring-nut 1 is effected by pushing the stopper 8 into hole 2 in ring-nut 1 as shown in FIG. 3. For this purpose, glass stopper 8 is provided (FIG. 2) with a groove 9 in its upper portion, which allows stopper 8 to be coupled with hole 2 of ring-nut 1 (FIG. 3). The lower portion of stopper 8 is provided with a groove 10 for coupling the stopper 8 with circular gasket 11 made of an elastic material, such as rubber.

In general, the assembly of the cap is carried out by fitting gasket 11 into groove 10 of glass stopper 8 and by then mounting the stopper with the gasket fitted thereto into the inside of ring-nut 1 through hole 2.

This operation is easily carried out since it does not require any special techniques, only simple pressure of the hands.

Once assembled, the component elements, i.e., ring-nut 1, stopper 8 and gasket 11 form the cap ensemble which is ready for use as an hermetic lock for jar 7. When the cap is assembled as hereinabove described, gasket 11 aligns itself within ring-nut 1 in correspondence with window 3, as seen in FIG. 3.

When it is necessary to clean the cap or substitute a new gasket, the reverse operation of the one herein above described is followed, whereby the three component elements (ring-nut, stopper and gasket) are easily disassembled. In order to hermetically seal jar 7, it is sufficient to simply screw the cap ensemble onto the jar neck 6. The hermetical seal is ensured by gasket 11 (FIG. 3) which is squeezed between shoulder 12 of groove 10 in stopper 8 and the upper rim of jar neck 6.

In order to open the jar, when it has been closed at atmospheric pressure, it will suffice to simply unscrew the cap which separates from the jar intact, that is, with ring-nut 1, stopper 8 and gasket 11 coupled to each other. In order to open the jar when it has been closed under vacuum, one proceeds in the following manner:

Ring-nut 1 is unscrewed slightly (FIG. 3) after which a pointed object, such as the point of a knife or a screw driver or the like, is inserted through window 3, pushing it between gasket 11 and the upper rim of jar neck 6 whereby to let air flow into the jar from outside. This will equalize the pressures within and without the jar. Then, the ring-nut can be unscrewed completely so as to separate the cap from the glass jar, the cap remaining also in this case, fully intact.

Variations and modifications can, of course, be made without departing from the spirit and scope of the invention.

Claims

Having thus described our invention, what we desire to secure by Letters Patent and hereby claim is:

1. An airtight container cap comprising a ring-nut provided, on the top surface thereof, with a circular hole and on the side surface thereof, with at least one window, a stopper adapted for removable engagement with the circular hole in said ring-nut and an elastic gasket provided with a central opening adapted to be removably inserted within said ring-nut in alignment with the window.

2. An airtight container cap according to claim 1, wherein the stopper includes a central portion having a diameter substantially equal to that of the ring-nut, an upper portion having a diameter substantially equal to that of the circular hole in the ring-nut to facilitate removable engagement of the stopper in said circular hole, and a lower portion having a diameter substantially equal to the diameter of the central opening in the gasket to facilitate the removable insertion of the lower portion within said central opening and the removable insertion of the gasket within said ring-nut.

3. An airtight container cap according to claim 1, wherein the ring-nut includes sealing means for securing the cap to a container provided with complementary sealing means.

4. An airtight container cap according to claim 3, wherein the sealing means in the ring-nut is an internal thread and the complementary sealing means on the container is a complementary thread.

5. An airtight container cap according to claim 1, wherein the ring-nut is formed of a plastic material, the stopper is formed of glass and the elastic gasket is formed of rubber.

6. In combination, an airtight container cap as claimed in claim 1 and a container.