DE1956784C3 - Screw cap closure for bottles - Google Patents

Description

35

The invention relates to screw cap closures for bottles and similar containers, their Cap has an annular groove on the inside of its bottom, the mean diameter of which is the same is the mean diameter of the mouth rim of the bottle that engages in it, and which is different from hers free, in comparison to the wall thickness of the mouth edge of the bottle wider end towards her The base is narrowed to a level below this wall thickness.

In known screw cap closures of this type, the annular groove has a wedge-shaped cross-section, so that when the cap is screwed on, its wall surfaces sit in a roof-shaped manner on the mouth edge of the bottle. The intended sealing of the bottle along two ^{circular lines 1} is, however, only rarely achieved with the desired reliability. Obviously, the reliably tight seal depends on the fact that the mouth edge of the bottle is really circular (but this is by no means always the case), has the same wall thickness and uniform surface over its entire circumference, and finally the mean diameter of the bottle neck edge and groove coincide with sufficient accuracy. These prerequisites are rarely met in their entirety.

The purpose of the invention is to create a screw cap closure of the type mentioned at the beginning Type in which there is a guarantee that the boundary surfaces of the annular groove are absolutely reliable Make a seal with the mouth rim of the bottle that engages in it.

This is achieved with a screw cap closure of the aforementioned type according to the invention by that the part of the groove narrowing from the free end is limited in one of cylindrical surfaces Part passes that is slightly narrower than the wall thickness of the mouth edge of the bottle this way it is achieved that the robber the cap üi oie groove penetrating mouth neck of the bottle the cylindrical wall surfaces of the forcing the narrow part of the groove apart within the scope of the elastic deformability of the screw cap, so that these wall surfaces are from the inside and outside under dynamic pressure or tensile stress against the Place the inner and outer surfaces of the mouth edge of the bottle, creating one on both sides cause a reliable tight seal.

The sealing effect of the screw cap closure according to the invention can be further improved as a result be that from the bottom of the groove in its of cylindrical surfaces limited. Part one into one sharp edge tapering annular elevation extends with an approximately wedge-shaped cross-section. The at Screw the cap firmly onto the face of the mouth rim of the bottle, pressing the raised portion With its easily deformable edge parts that form the sharp edge, it is reliable No more the face of the bottle neck rope · »;! then if that area doesn't be like it should be smooth and uniform over its full extent.

The elastic resilience of the groove walls can advantageously be increased in that the groove is laterally bounded by annular extensions of the cap base

The invention has proven itself in screw cap closures for bottles made of hard material such as glass or metal, as well as for plastic bottles. One is only for bottles made of hard material for the screw cap according to the invention Choose a plastic with a low stretch, but for bottles made of materials with a low stretch a cap made of a relatively hard material, e.g. B. Kunstharzpreßstoff, then in the latter Trap the seal by elastic deformation of the mouth edge of the bottle and by cutting the sharp edge on the ring-shaped ridge at the bottom of the cap into the face of the Bottleneck results.

In the drawing is an embodiment of the subject matter of the invention Screw cap closure shown schematically, namely shows

F i g. 1 those responsible for the tight seal Parts of a screw cap and the bottle neck in an axial section immediately before Screwing down the cap,

F i g. 2 the same closure parts after tightening the cap on the bottle neck.

The cap 2, which is preferably made of plastic, has an annular groove 3 on the inside of its bottom, the mean diameter of which corresponds to the mean diameter of the mouth rim 1 of a bottle. The wall parts 3 a of the groove 3 gradually approaching from their free edges go into one of coaxial cylindrical surfaces 3 b

limited part of the groove, which is slightly narrower than the wall thickness of the mouth rim of the bottle. With "slightly narrower" it should be said that the cap is subject to deformation of the groove walls or the bottle neck lying in the elastic range should be screwed on this.

From the bottom of the groove protrudes in the part delimited by the surfaces running annular

of ring-shaped approaches

and 6 limited.

1 sheet of drawings

Claims (3)

Patent claims: 1. Screw cap closure for bottles and similar containers, with an annular groove arranged on the inside of the cap base, the mean diameter of which is equal to the mean diameter of the thread-free mouth rim of the bottle engaging in it, and it is free from ih- ίο purely in comparison to the wall thickness of the The mouth edge of the I tab wider end narrows towards its base to a dimension below this wall thickness, characterized in that the part (3 a) of the groove (3) narrowing from the free end into a part delimited by simultaneous.?) Cylindrical surfaces ( 3 b) passes, which is slightly narrower than the wall thickness of the mouth edge (1) of the bottle, ao 2. Screw cap closure according to claim 1, characterized in that extending from the base of the groove (3) in the part (3 b) delimited by cylindrical surfaces, an annular elevation (4) with a wedge-shaped cross-section extending into a sharp edge. 3. Sehrai.bkappenverschluß according to the claims 1 and 2, characterized in that the groove is laterally formed by annular projections of the cap base is limited.