WO1999042411A1

WO1999042411A1 - Method and mould for manufacturing glass containers provided with an undercut

Info

Publication number: WO1999042411A1
Application number: PCT/IT1998/000358
Authority: WO
Inventors: Angelo Breviari
Original assignee: Bormioli Rocco & Figlio S.P.A.
Priority date: 1998-02-18
Filing date: 1998-12-10
Publication date: 1999-08-26
Also published as: IT1306035B1; ITPR980011A1

Abstract

The invention falls within the sector of the production of glass containers. A mould (2) for manufacturing glass containers (3) provided with an undercut (4) comprises at least one zone (17) shaped so as to provide an undercut (4) in the final container (3) and comprises a plurality of segments (9) provided with means (10, 11, 12, 13, 14) which regulate opening and closing thereof and are formed so as to allow opening and closing of the mould also in the zones intended for the formation of undercuts (4) in the final container (3), by means of rotation of the segments (9) about pins (11). The method envisages the closing of a first conventional mould (2) followed by the closing of the second mould (2) intended to produce undercuts; injection of molten glass and first partial cooling; opening of the second mould (2); opening of the first mould (1) with extraction of the container (3).

Description

METHOD AND MOULD FOR MANUFACTURING GLASS CONTAINERS PROVIDED WITH AN UNDERCUT

TECHNICAL FIELD AND BACKGROUND ART. The present invention relates to a method and a mould for manufacturing glass containers provided with an undercut.

Numerous methods and moulds for manufacturing glass containers, in particular small bottles or phials for perfumes, are known, but moulds designed to allow the formation of undercuts do not appear to exist. In the case, in fact, of glass containers of various shapes provided at the top with a mouth which is narrow in size and in any case smaller than the larger diameter of the container, often there arises the need of being able to create, around said mouth, annular channels or grooves which are enclosed between the mouth and the external shoulder or the external side surface of the container. Hitherto a mould which allows this has not yet been devised and therefore said grooves or undercuts have been simply formed more or less manually by means of a pressure exerted on the container soon after it has left the mould and still has a sufficiently high enough temperature to allow partial modifications to the shape of the container itself. However, the pressure exerted manually, for example by means of a piston on the top part of the container during cooling has the drawback that it is unable to produce containers where the undercut has a very precise shape. In particular, it is not possible to ensure uniformity of the distance between the plane of the mouth of the container and the plane of the external shoulder of the container itself. DISCLOSURE OF INVENTION. An object of the present invention is that of eliminating the abovementioned drawbacks and providing a method and a mould which allow the manufacture of glass containers provided with undercuts, wherein it is possible to ensure uniformity of the distance between the plane of the container mouth and the plane of the external shoulder with a maximum tolerance of a few tenths of a millimetre. A further object is that of providing the above in an extremely simple and low-cost manner.

Said objects are fully achieved by the method and the mould which form the subject of the present invention and which are characterized by the contents of the claims indicated below. In particular the method envisages the steps involving closing of a first mould of the conventional type without undercuts, shaped so as to produce a first part of a container without undercuts; closing of a second mould shaped so as to produce a second part of the container provided with at least one undercut zone; injection of molten glass; first partial cooling; opening of the second mould; opening of the first mould; completion of cooling of the container.

Opening of the second mould is preferably performed by the use of resilient means enclosed in the first mould, while closing of the second mould is performed by means of pressing elements operated by compressed air. The mould comprises in an original manner at least one zone shaped so as to provide an undercut in the final container and said zone is preferably formed with a plurality of segments provided with means which regulate opening and closing thereof and are formed so as to allow opening and closing of the mould also in the zones which form an undercut in the final container. BRIEF DESCRIPTION OF DRAWINGS. These and other characteristic features will emerge more clearly from the following description of a preferred embodiment illustrated, purely by way of a non-limiting example, in the accompanying plates of drawings, in which:

- Figures 1 and 2 show a vertical cross-sectional view through the middle of the mould and a plan view thereof, respectively, with a part of the mould being opened and the remaining part of the mould being closed;

- Figure 3 shows a front view of the container obtained with the mould according to Figures 1 and 2.

BEST MODE FOR CARRYING OUT THE INVENTION.

1 denotes a first mould of a substantially conventional type which has associated with it in an original manner a second mould 2 which allows the manufacture of glass containers 3 provided with an undercut 4, that is at least one zone in the form of a recess lying between an upper plane 5 of a mouth 7 of the container and a plane 6 ^f an external shoulder 8 of the container 3. The first mould 1 is a mould of the traditional type consisting of two hinged valves which open and close by means of a hinge, not shown, in accordance with a known technique. Since, however, with this mould it would not be possible to form undercut zones in the final container, the Applicants, after extensive research, have managed to develop the second mould 2 which, as illustrated in Figures 1 and 2, comprises four segments 9 each of which extends through 90° and which are mounted on arms 10 pivotably hinged on a pin 11. The number of segments 9 may vary, however, and it is possible to envisage, for example, three 120° segments or five 72° segments.

The segments 9 of the second mould open and close in the top part of the first mould in a manner similar to that of the petals of a flower. This is made possible by special actuating means which, for the opening step, comprise resilient means consisting of first springs 12 and second springs 13, while for the closing step, they comprise small pneumatically operated pistons 14.

The first springs are compression springs housed in seats formed in the body of the first mould 1 and act between the pin 11 and the segment 9, while the springs 13 act beyond the pin 11 (on the opposite side to the segment 9), are contained in an external casing 15 and operation thereof is adjustable by means of screws not shown.

The small pistons are instead operated by means of the injection of compressed air or other fluid under pressure introduced via pipes 16 only partially shown in Figure 2. Each segment has a zone 17 which rests on the first mould 1 and is shaped so as to provide an undercut 4 in the final container 3. The present method envisages in an original manner that, after closing of the first mould 1 of the conventional type, the second segment-type mould 2 is closed. The traditional steps of injection of a gob of molten glass and subsequent partial cooling follow. The second mould is then opened in a petal-like manner, followed by opening of the first mould, with extraction of the container and completion of cooling. With the method and the mould according to the present invention it is possible to manufacture glass containers provided with undercuts in an extremely simple and precise manner.

In fact, it is possible to ensure the uniformity of the distance between the plane 5 of the mouth and the plane 6 of the shoulder with a maximum tolerance of a few tenths of a millimetre.

Claims

1. Method for manufacturing glass containers provided with a mouth and at least one undercut, characterized in that it envisages the following steps:

- closing of a first conventional mould without undercuts, shaped so as to produce a first part of a container without undercuts;

- closing of a second mould shaped so as to produce a second part of the container provided with at least one zone which is undercut or in any case in the form of a groove or recess having a level lower than that of the mouth and an external shoulder of the container;

- injection of molten glass;

- first partial cooling;

- opening of the second mould;

- opening of the first mould with extraction of the container;

- completion of cooling of the container.

2. Method according to Claim 1, in which opening of the second mould is performed by means of the action of resilient elements at least partially housed in the first mould.

3. Method according to Claim 1 , in which the step involving closing of the second mould is performed by means of the injection of compressed air.

4. Mould for manufacturing glass containers provided with an undercut or at least one recess having a level lower than a mouth of the container and an external shoulder of the said container, characterized in that it comprises at least one zone (17) shaped so as to provide an undercut (4) in the final container (3).

5. Mould according to Claim 4, characterized in that it comprises a plurality of segments (9) provided with means (10, 11, 12, 13, 14) which regulate opening and closing thereof and are formed so as to allow opening and closing of the mould also in the zones intended for formation of undercuts (4) in the final container (3).

6. Mould according to Claim 5, in which each segment (9) is fixed to an arm (10) which is pivotably hinged on a rotational pin (1 1) and actuated during opening and closing of the mould, respectively, by resilient means (12, 13) and by pneumatically operated pressing elements (14).

7. Mould according to Claim 5, in which there are four segments arranged at 90┬░.

8. Mould according to Claim 6, in which the resilient means comprise first springs (12) housed at least partially in the first mould (1) and second springs (13) housed in an external casing (15).

9. Mould according to Claim 6, in which the pressing elements ( 14) comprise small pistons (14) actuated by the injection of a fluid under pressure supplied via pipes (16).

10. Glass container, characterized in that it is manufactured with a method according to any one of Claims 1 to 3 or with a mould according to any one of Claims 4 to 9.