EP0427686A1

EP0427686A1 - Screw-type closure cap with a yielding thread

Info

Publication number: EP0427686A1
Application number: EP90830501A
Authority: EP
Inventors: Paolo Call; Franco Iacoboni; Oliviero Zanardo
Original assignee: Italcaps SpA
Current assignee: Italcaps SpA
Priority date: 1989-11-06
Filing date: 1990-11-02
Publication date: 1991-05-15
Also published as: ZA908845B; IT1237061B; IT8948525A0

Abstract

It is described a screw-type closure cap, in which a lateral skirt or ring (14) is designed to screw engage the neck of a container (12), which cap is characterised in that the thread (24), located in the inner wall of said lateral ring (14), is provided with a hollow cross-section.

Description

The present invention refers to a screw-type cap for closing containers, in which the thread is carried out yieldable, instead of having a solid cross-section as it happens in the known caps.
In the Italian patent 1.211.905 of the Applicant, it is described a composite cap for the closure of a container, comprising a ring or lateral skirt portion, threaded and plastic molded and provided with a housing to accomodate a metal cover portion provided with a sealing gasket.
Such a cap is provided with rigid threads, having a solid cross-section, from a plastic material, carried out by molding the plastic material so as to leave a thraed projecting from the inner wall of the ring portion.
The presence of a similar thread, with a solid cross-section, involves a stiffening of the plastic ring portion as a whole and thus gives rise to some drawbacks on the applying the cap to the container in the high speed automatic capping machines.
In fact, such a cap must be located on the mouth of the container with a relative accuracy and can be screwed down only by exercising some force on it.
If the placement is not very exact, the motion of rotation provided to the cap by the closing unit causes the cap to cross, since not all the threads of the cap succeed in positioning themselves under the corresponding threads of the container.
Furthermore, the excessive force applied by the closing unit gives rise to a fast wear of the closing unit itself and can also cause an aesthetic damage of the cap.
Therefore, the main object of the present invention is to provide an improved closure cap of the screw type, which allows for a better use and a slighter wear of the high speed automatic capping machines.
Another object of the present invention is to provide an improved closure cap of the screw type, of a simple and cheap construction, suitable for mass production.
According to the present invention, a screw-type closure cap, in which a lateral skirt or ring is designed to screw engage the neck of a container, is characterised in that the thread, located in the inner wall of the lateral ring, is provided with a hollow cross-section.
The main advantage of the screw-type closure cap, improved according the present invention, consists in that the new thread structure allows for an easiness in closing the package, since now a slight pressure sufficies to cause the threads of the cap to be engaged under the corresponding threads of the container. At that moment, only a little rotation is needed to terminate the operation of closing the package.
Another advantage of the use of the screw-type closure cap, improved according to the present invention, is the slighter wear of the closing unit and container handling units in the capping machines.
A further advantage of the use of the screw-type closure cap, improved according to the present invention, is the increased closure speed, and then working and production speed, of the capping machines themselves.
Still another advantage of the use of the screw-type closure cap, improved according to the present invention, lies in that the number of the losses, wasted due to the missing closure of the packages, noticeably decreases.
In the following, the present invention will be further clarified from the description of one form of practical embodiment of the screw-type closure cap, with a yielding thread, according to the present invention, the description being made in a purely illustrative and not limiting way, with reference to the accompanying drawing, in which:

Figure 1 is a perspective view, part in cross-section, of an improved screw-type closure cap according to the present invention;
Figure 2 is an improper cross-section view on threads of the present closure cap, made along line II-II of figure 1; and
Figure 3 is a partial vertical cross-section view of the present closure cap, made along line III-III of figure 2.

With reference to the figures of the accompanying drawing, an example of embodiment of a screw-type closure cap 10, improved according to the present invention, for closing a container 12, comprises a plastic molded ring 14 and a separate metal cover 16.
Generally, the metal cover 16 is comprised of a pressed and blanked disk, with a gasket 18, of a sprayed or other kind gasket. The gasket 18 can be the usual gasket of sprayed plastisol or a cut disk fastened to the edge or to the full surface of the cover 16.
The metal cover 16 is mounted on the upper portion of the plastic ring 14, in a housing upwardly delimited by a circumferential shoulder 20. More exactly, the metal cover 16 is inserted from the upper edge of the ring 14 and is pressed downwardly until its circumferential edge 22 snaps under the circumferential shoulder 20. The circumferential edge 22 of the metal cover 16 is loosely accommodated under the circumferential shoulder 20, so that the metal cover 16 can vertically reciprocate for while with respect to the plastic ring 14.
The circumferential edge 22 of the cover 16 is shaped so that it snaps under the circumferential shoulder 20 when the cap is assembled and afterwards it can no longer come out from its housing.
The plastic ring 14 has threads 24, which engage corresponding threads 26 on the container. According to the present invention, the threads 24 are yieldable. In the particular embodiment shown in the drawing, the threads 24 have a cross-section shape like a projecting tab or a V-shape, with a side of V merging in the inner wall of the lateral ring 14, as it is better shown in figure 3. The corresponding threads 26, provided on the container 12, are on the contrary solid in cross-section, as it is clearly shown in figure 3.
The particular structure of the threads 24 in cross-section causes the latters to be resilient enough to bend and clamber over the corresponding threads 26 of the container 12, so that in this way an accurate positioning of the cap 10 on the mouth of the container 12 is achieved, even with a lighter force applied by the closing unit of the capping machine.
When the cap 10 has been accurately positioned on the mouth of the container 12, it sufficies that the closing unit only causes a slight rotation of tha cap 10 with respect to the container 12, in order to complete the closing of the package.
In a variation, the threads 24 are provided with a circular cross-section shape, even quite a lot flattened at the area near the inner wall of the lateral ring 14.
Furthermore, as it is better shown in figure 2, the tread 24 has some tapering, joining the inner wall of the lateral ring 14 at its end areas 28, 30, in order to facilitate the screwing down of the cap.
The joining end areas 28, 30 allows the thread 24 to become stiffened, avoiding that it collapses at the opening of the package, when the cap is screwed out.
The plastic ring 14 terminates, at its lower end, in a band 32 for evidencing the tampering.
The tampering evidencing band 32 has a continuous circumferential bead 34, facing towards the inside of the cap. The continuous circumferential bead 34 has a shape like a tab with a V-shaped vertical cross-section with respect to the band 32, as it is better shown in figure 3, and it is designed to engage a rib 36 provided on the neck of the container 12 when the cap 10 is in the position of complete closure of the container 12.
The tampering evidencing band 32 is connected to the plastic ring 14 by means of a set of bridges 38, which remain in place after an interrupted weakening groove 40 has been carried out around the whole circumference of the ring 14 of the closure cap. Obviously, the bridges 38 fasten the band 32 to the ring 14 of the cap and are broken upon the opening of the package.
In the present embodiment, the yielding thread 14 is comprised of a number of discontinued threading sections, separated from one another, but it can be comprised of only a single continuous threading section, according to the pitch of the threading itself.
It is obvious that other numerous and different changes and modifications can be performed by those skilled in the art on the above described embodiment of the present invention, without departing from its scope. It is intended therefore that all these changes and modifications are encompassed in the field of the invention.

Claims

A screw-type closure cap, in which a lateral skirt or ring (14) is designed to screw engage the neck of a container (12), which cap is characterized in that the thread (24), located in the inner wall of said lateral ring (14), is provided with a hollow cross-section.
A screw-type cap according to claim 1, characterized in that the hollow cross-section of the thread (24) has a V shape, with a side of V merging in the inner wall of the lateral ring (14).
A screw-type cap according to claim 1, characterized in that the hollow cross-section of the thread (24) has a circular shape, even quite a lot flattened at the area near the inner wall of the lateral ring (14).
A screw-type cap according to any one of the preceding claims, characterized in that the hollow cross-section thread (24) has a tapering, joining the inner wall of the lateral ring (14) at its end areas (28, 30).
A screw-type cap according to any one of the preceding claims, characterized in that the thread (24) is comprised of a number of discontinued threading sections, separated from one another.
A screw-type cap according to any one of the claims 1 to 4, characterized in that the thread (24) is comprised of only a single continuous threading section.
A screw-type cap according to any one of the preceding claims, characterized in that a circumferential shoulder (20) is provided on the inner wall of said lateral ring (14), and a metal cover (16) is snap housed under it.
A screw-type closure cap, with a yielding thread, substantially as hereinbefore described with reference to the accompanying drawing.