WO2007135558A1

WO2007135558A1 - Method for manufacturing stoppers

Info

Publication number: WO2007135558A1
Application number: PCT/IB2007/001398
Authority: WO
Inventors: Daniele Dalla Guarda; Corrado Dalla Guarda
Original assignee: Main Group Corporation S.R.L.
Priority date: 2006-05-19
Filing date: 2007-05-15
Publication date: 2007-11-29
Also published as: WO2007135558A9; ITVI20060157A1

Abstract

A method for manufacturing stoppers (1), comprising the operations of preparing a mold (2), inside which at least one cavity (3) is formed which is connected to the outside by means of a front opening (4); associating an injector with the mold (2) at the front opening (4). The method also includes an injection of plastic material into a first portion (31) of the cavity (3) to obtain a first contoured body (6) and a second injection of plastic material into a second portion (32) of the cavity (3) to obtain a second contoured body (7) which mates by spontaneous adhesion with the first contoured bod (6).

Description

METHOD FOR MANUFACTURING STOPPERS Technical field

The present invention relates to a method for manufacturing stoppers, particularly plastic stoppers suitable for bottles. Background art

It is known that bottles, especially wine bottles, are closed by applying to the neck of said bottles stoppers which, depending on production requirements, are made of cork, plastics, composite material or metallic material with a crown-like shape. Crown stoppers are applied to the top rim of the neck of the bottle, with respect to which they remain always external in order to be removed by means of so-called bottle openers, which are suitable for opening the bottle quickly and effectively.

Stoppers made of cork, plastics or a combination thereof can instead be distinguished into two main categories.

The first category includes stoppers intended to be inserted almost fully into the neck of the bottle, from which they are extracted by means of what are known as screw, spiral or worm corkscrews.

The second category, to which the present invention refers specifically, comprises stoppers which are characteristically T-shaped along a longitudinal sectional plane.

Such stoppers are composed of a stem, which is inserted in the neck of the bottle, and a disk, which is associated with the stem, has a more or less substantial thickness, remains outside the neck of the bottle and is directly available to the user, who by maneuvering it pulls the stopper out of the bottle without resorting to any kind of corkscrew.

Stoppers of both categories are made of composite material, which in some cases comprises portions made of cork and portions made of synthetic material, while in other cases comprises portions only made of plastic material, although often the composition is variable from portion to portion. T-shaped synthetic stoppers have a generally cylindrical solid or hollow contoured body, suitable to be contained in the neck of the bottle, and an upper dome, the above mentioned disk, which protrudes from the neck of the bottle and can be accessed comfortably by the user. These known types of synthetic stopper are manufactured substantially by means of processes which provide for the injection- molding, with plastic material, of their components, which as mentioned are the contoured body and the upper dome.

The main drawback observed in the cited methods is the number of items of manufacturing equipment, dedicated and specific for each component of the stopper, that the manufacturer must have.

Methods for manufacturing contoured synthetic stoppers in fact currently use as many manufacturing molds as there are components, i.e., one manufacturing mold for the contoured body and one for the upper dome.

This inevitably entails that the corresponding operations for injection- molding plastic material occur in separate and distinct pieces of equipment, and it is therefore necessary to mate the resulting semifinished components by means of a suitable operation, and with appropriately provided connecting means, in order to obtain the final stopper.

Accordingly, this leads to another drawback, which is caused by the laboriousness of the operations to be performed in order to obtain the finished product. Disclosure of the invention The present invention seeks to solve the drawbacks of the background art cited above.

The aim of the present invention is to provide a method for manufacturing composite plastic stoppers which is quicker and less complex and complicated than known methods. Within this aim, an object of the present invention is to reduce, with respect to the background art, the number of items of manufacturing equipment, such as molds, required to provide T-shaped stoppers made of plastic material.

Another object of the invention is to reduce, all other factors involved being equal, the production cost of plastic stoppers suitable in particular for bottles.

This aim and these and other objects which will become better apparent hereinafter are achieved by a method for manufacturing stoppers according to claim 1, to which reference is made for the sake of brevity. Other detail characteristics of the method according to the invention are provided in the corresponding dependent claims.

Advantageously, the method according to the invention allows to perform in a single mold both injection-moldings of the components of a stopper, the contoured body and the upper dome. In this manner, the procedures that provide T-shaped synthetic stoppers are simplified and shortened with respect to the background art.

In the method according to the invention, in fact, the mating between the outer dome and the contoured body occurs by utilizing the inherent characteristics of an injection-molded plastic material, which, as is known, can adhere, during the method, spontaneously and autonomously to the part to which it is applied.

By doing so, the need is eliminated, in the invention, to perform a separate operation in order to mate the upper dome and the contoured body of the stopper, using connecting means such as for example adhesives, as provided by similar processes of the known type.

Also advantageously, the invention allows to reduce, with respect to the background art, the number of pieces of equipment required to produce synthetic stoppers, especially T-shaped ones, with the obvious economic and logistical advantages that arise from this. Brief description of the Drawings

Further characteristics and advantages of the method claimed herein will become better apparent from the following detailed description of a preferred embodiment of the invention, given by way of non-limiting example in relation to the accompanying drawings, wherein:

Figure 1 is a longitudinal sectional view of a step of the method according to the invention;

Figure 2 is a longitudinal sectional view of another step of the method according to the invention; Figure 2a is a longitudinal sectional view of a stopper obtained with the method according to the invention. Ways of carrying out the invention

The method according to the invention for manufacturing stoppers, of the type shown in Figure 2a and generally designated by the reference numeral 1, is explained hereinafter with the aid of figures which illustrate it schematically, in a partial and simplified manner. Such method comprises the following operations:

- preparing a mold 2, inside which a cavity 3 is formed which is connected to the outside by means of a front opening 4; - associating an injector, not shown for convenience in description, with the mold 2 at the front opening 4.

According to the invention, the method further includes the following operations:

- injecting plastic material into a first portion 31 of the cavity 3 to obtain a first contoured body 6;

- injecting plastic material into a second portion 32 of the cavity 3 to obtain a second contoured body 7 which mates by spontaneous adhesion with the contoured body 6.

In this example of application, the second portion 32 has, in a transverse cross-section, dimensions which are larger than those of the first portion 31.

There can be further applications of the method according to the invention, not accompanied by reference drawings, in which the first portion has larger dimensions than the second portion. In any case, a sort of upper dome is formed which in the first case is constituted by the second contoured body and in the second case is constituted by the first contoured body and which, when the stopper is in the condition for application, remains outside the neck of the bottle.

During the injection of plastic material into the second portion 32 of the cavity 3 and until said injection ends, the second portion 32 is interposed between the first portion 31 and a lid 5 which is associated with the mold 2.

The injector is connected to an injection nozzle 15, which is formed in the central region of the lid 5 which is associated with the mold 2.

The injection nozzle 15 is connected initially to the first portion 31 of the cavity 3 and then, as the plastic material is injected into the first portion 31, to the second portion 32 of the cavity 3.

Preferably but not necessarily, the plastic material injected into the first portion 31 is different from the plastic material injected into the second portion 32. More specifically, both plastic materials are constituted by respective mixtures of elastomers, which in any case have mutually different compositions according to the distinct mechanical properties that must be achieved by the first contoured body 6 and by the second contoured body 7.

Each of the operations for injecting plastic material performed in the mold 2 provides for an injection molding.

In this case, and preferably, both the first portion 31 and the second portion 32 of the cavity 3 have, in transverse cross-section, a circular profile, but it is clear that in other solutions, not shown, said profile can be modified, especially as regards the upper dome. Therefore, by virtue of this constructive solution, the second portion 32 has a larger diameter than the first portion 31.

Figures 1 and 2 show that the mold 2 comprises:

- two mold parts 21 and 22, which face each other and are arranged symmetrically with respect to the longitudinal axis Y formed by a channel 8 provided inside the mold 2;

- a plug 9, which is coupled to the mold 2 by insertion, for a preset length L, in the channel 8 along the longitudinal axis Y.

The described constructive variation entails that the channel 8 is a through channel and mutually divides the mold parts 21, 22, which are mutually connected at one end by means of the lid 5 and at the opposite end by means of the plug 9.

In greater detail, after insertion in the channel 8 and before the injection of plastic material into the first portion 31 of the cavity 3, the plug 9 is inserted in the channel 8 along the entire length thereof. Therefore, in this step of the method according to the invention the plug 9 occupies completely the channel 8 and substantially closes the second portion 32 of the cavity 3.

According to the preferred embodiment of the invention described here, the first portion 31 of the cavity 3 is formed by a central recess 10, which is formed axially in the plug 9, and the second portion 32 of the cavity 3 is formed by a perimetric hollow 11, which is formed on the inner wall 8a that delimits the channel 8 and in front of the front opening 4 of the mold 2.

In this case, therefore, the cavity 3 is formed in the channel 8 by the central recess 10, which has a U-shaped longitudinal cross-section, and by the region of the channel 8 that is delimited by the perimetric hollow 11.

In view of the above, after the insertion of the plug 9 in the channel 8 and before the injection operations, the central recess 10 is connected directly to the injector, in the specific case by interposing the lid 5. Preferably but not exclusively, the method according to the invention comprises the sliding of the plug 9 along the longitudinal axis Y and toward the outside of the mold 2 in order to release the second portion 32 of the cavity 3.

The sliding of the plug 9 occurs during the injection of plastic material into the first portion 31 of the cavity 3 and before the injection of plastic material into the second portion 32 of the cavity 3.

Preferably, the sliding of the plug 9 is sudden, but it is evident that in other embodiments of the method according to the invention it can be progressive and modular. The method according to the invention includes stopping the sliding of the plug 9 after it has traveled a distance D which is equal to the thickness S of the second portion 32 of the cavity 3 and consequently to the thickness of the second contoured body of the stopper 1, as clearly shown in Figure 2. In practice, when its movement is blocked, the plug 9 protrudes from the mold 2 by a total length which is equal to the sum of the covered distance D and of the portion T by which it protruded initially before being moved.

The sliding of the plug 9 is stopped by way of stroke limit means, generally designated by the reference numeral 12 and, in the current example, arranged inside the channel 8.

According to other embodiments, not shown, the stroke limit means can be arranged outside the channel provided in the mold.

The stroke limit means 12 comprise an annular step 13, which protrudes from the internal wall 8a that delimits the channel 8, and an undercut 14, which is formed on the outer wall 9a of the plug 9.

In further embodiments of the invention, the plug can be inserted within the through channel for a shorter preset length, occupying said channel only partially and leaving free the second portion of the cavity. On this occasion, the injector is connected directly to the second portion of the cavity and through it to the central recess of the plug.

In these operating conditions, the plug can still be movable and can slide by a preset distance or be kept stationary in position, depending on the length given during design to the contoured body of the stopper. If the plug is fixed, it can be provided conveniently monolithically with the mold parts: in this case, of course, the channel inside the mold will not be a through channel.

The method according to the invention comprises an extraction of the stopper 1 from the mold 2, performed after the injections of plastic materials into the first and second portions 31, 32 of the cavity 3.

The method according to the invention further comprises a reinsertion of the plug 9 into the channel 8 by the predefined length L, which is performed after the injection of plastic material into the second portion 32 of the cavity 3, particularly after said extraction of the stopper 1 from the mold 2.

Reinsertion occurs automatically by way of actuation means, which are not shown for the sake of convenience in description, are of the type that is per se known to the person skilled in the art, and are associated with the end 9a of the plug 9. The colorings of the first contoured body 6 and of the second contoured body 7 of the stopper 1 may be any and may also mutually differ.

From what has been described above it is therefore evident that the method for manufacturing stoppers according to the invention achieves the previously mentioned aim and objects and provides the above mentioned advantages.

The method according to the invention provides a T-shaped synthetic stopper by injection-molding within a single mold of all of its components, utilizing in practice the spontaneous adhesion of the second contoured body to the first contoured body. This allows to obtain a manufacturing method which is performed with less complex and swifter procedures than the background art without compromising the quality of the end product.

Another advantage is further constituted by the containment of production costs, all other involved factors being equal. During production, it is possible to apply changes in application to the method according to the invention for manufacturing stoppers, said changes consisting for example of a different shape of the mold used, especially of the cavity provided inside it.

Finally, it is evident that many other variations can be made to the method according to the present invention without thereby abandoning the principles of novelty that are inherent in the appended claims, and likewise it is evident that in the practical embodiment of the invention the materials, shapes and dimensions of the described details may be any according to requirements and may be replaced with other technically equivalent ones. The disclosures in Italian Patent Application No. VI2006A000157, from which this application claims priority, are incorporated herein by reference.

Claims

1. A method for manufacturing stoppers (1), comprising the following operations:

- preparing a mold (2), inside which at least one cavity (3) is formed which is connected to the outside by means of a front opening (4);

- associating at least one injector with said mold (2) at said front opening (4), characterized in that it includes the following operations:

- injecting plastic material into a first portion (31) of said cavity (3) to obtain a first contoured body (6);

- injecting plastic material into a second portion (32) of said cavity (3) to obtain a second contoured body (J) which mates by spontaneous adhesion with said first contoured body (6).

2. The method according to claim 1, characterized in that said first portion (31) or said second portion (32) has, in a transverse cross-section, larger dimensions than the other portion.

3. The method according to claim 1, characterized in that during said injection of said plastic material into said second portion (32), said second portion (32) is interposed between said first portion (31) and said injector.

4. The method according to claim 1, characterized in that at least one of said first and second portions (31, 32) of said cavity (3) has a circular profile in a transverse cross-section.

5. The method according to claim 1, characterized in that said plastic material injected into said first portion (31) is different from said plastic material injected in said second portion (32).

6. The method according to claim 1, characterized in that each of said injections provides for an injection molding.

7. The method according to claim 3, characterized in that said mold (2) comprises: - two mold parts (21, 22), which face each other and are arranged symmetrically with respect to the longitudinal axis (Y) formed by a channel (8) formed within said mold (2);

- a plug (9), which is coupled to said mold (2) by means of an insertion for a preset length (L) in said channel (8) along said longitudinal axis (Y).

8. The method according to claim 7, characterized in that said channel

(8) is a through channel and mutually divides said mold parts (21, 22), which are connected at one end by means of a lid (5), which is associated with said mold (2), and at the opposite end by means of said plug (9).

9. The method according to claim 7, characterized in that said mold parts are formed monolithically with each other and with said plug.

10. The method according to claim 7, characterized in that after said insertion in said channel (8) and before said injection of said plastic material into said second portion (32) of said cavity (3), said plug (9) occupies said channel (8) completely and substantially closes said second portion (32) of said cavity (3).

11. The method according to claim 7, characterized in that said first portion (31) of said cavity (3) is formed by a central recess (10), which is formed axially in said plug (9), and said second portion (32) of said cavity (3) is formed by a perimetric hollow (11), which is formed on the inner wall (8a) which delimits said channel (8) and in front of said front opening (4) of said mold (2).

12. The method according to claim 11, characterized in that said insertion of said plug (9) in said channel (8) connects said central recess (10) to said injector by means of said lid (5).

13. The method according to claim 7, characterized in that said plug

(9) slides along said longitudinal axis (Y) toward the outside of said mold (2) in order to free said second portion (32) of said cavity (3).

14. The method according to claim 13, characterized in that said sliding of said plug (9) occurs before said operation for injecting said plastic material in said second portion (32) of said cavity (3).

15. The method according to claim 13, characterized in that said sliding of said plug (9) occurs during said injection of said plastic material in said first portion (31) of said cavity (3).

16. The method according to claim 13, characterized in that said sliding occurs suddenly.

17. The method according to claim 13, characterized in that said sliding occurs progressively.

18. The method according to claim 13, characterized in that said sliding of said plug (9) is stopped, by way of stroke limit means (12), after said plug (9) has covered a distance (D) equal to the thickness (S) of said second portion (32) of said cavity (3).

19. The method according to claim 18, characterized in that said stroke limit means (12) are arranged inside said channel (8).

20. The method according to claim 18, characterized in that said stroke limit means are arranged outside said channel.

21. The method according to claim 1, characterized in that it comprises an extraction of said stopper (1) from said mold (2), which is performed after said injections of said plastic materials into said first portion (31) and second portion (32) of said cavity (3).

22. The method according to claim 21, characterized in that it comprises an operation for reinserting said plug (9) into said channel (8) by said predefined length (L), which is performed after said extraction of said stopper (1) from said mold (2).