EP0791538A1 - Method and device for closing a metallic container - Google Patents

Abstract

The method involves closing a metal container (1) by a lid (10) which has a bottom (11), a side wall (12) and a rim (13). A sealing joint (17) is placed in the rim on periphery of the container opening (16). The lid is placed on the container by applying a pressure on it in order to crush the joint between the container and the rim. The joint is then locked by stamping the lid side wall onto the container. The lid is stamped onto the container on segments divided along the container perimeter. Stamping of the lid side wall is also made onto the large walls of the container.

Description

The present invention relates to metal containers of any shape, for example truncopyramidal, and intended to contain paint in particular. After filling, these containers are conventionally closed with a lid.

The invention relates more particularly to a method for closing such containers. It also relates to a machine for implementing this method.

In known manner, the truncopyramidal or cylindrical containers are closed using a cover having tabs, perpendicular to the plane of the cover.

A container of this type is described in document FR-2 248 097.

After filling the container, the lid is placed on the latter, a seal being placed between the container and the lid, at the periphery of the opening of the container. Pressure is exerted on the cover to compress the seal and this pressure is maintained by blocking the tabs, under the edge of the container.

This closure has provided users with satisfaction for many years.

However, the cover is relatively difficult to remove. It is, in fact, necessary to lift each tab to release the cover, which is tedious. In addition, when it is desired to replace the cover, it is difficult to seal the closure.

Finally, the presence of the legs is unattractive.

It therefore appeared necessary to develop a new closure process which overcomes these drawbacks.

The invention thus relates to a method of closing a metal container with a cover comprising a bottom, a side wall and a flange, according to which a seal is placed at the periphery of the opening of the container and, the cover being placed on the container, pressure is applied to the cover to crush the seal between the container and the rim of the cover, characterized in that the seal is blocked by stamping the side wall of the cover on the container .

Advantageously, the cover is stamped on the container at points distributed around the periphery of the container, and preferably in segments.

When the opening is of substantially rectangular shape, the stamping is preferably carried out in each corner of the container.

In this case, a stamping is advantageously carried out in the large walls of the container and preferably, substantially in the center of these walls, when the nature of the product contained in the container requires it.

Preferably, when the opening of the container is round, the stamping of the lid on the container is carried out at regularly distributed points or segments.

The rim of the cover advantageously has a concavity facing the bottom of the cover, in which said seal is placed, and ends in an edge rolled towards the outside of the cover.

The invention also covers a machine for implementing the closing process.

This machine comprises means for applying a compressive force to the cover when the latter is in place on the container and means for drawing the lid on the container.

• la figure 1 est une vue de côté d'un récipient troncopyramidal, fermé par un couvercle selon l'état de la technique,
• la figure 2 représente une demi-vue en coupe d'un exemple de couvercle selon l'invention,
• la figure 3 comporte les figures 3a à 3c qui sont des vues partielles en perspective, avec une section droite vue en coupe, d'un exemple de couvercle selon l'invention et d'un récipient dans trois étapes du procédé de fermeture selon l'invention,
• la figure 4 est une vue partielle en perspective, avec une section droite vue en coupe, d'un récipient fermé avec un couvercle selon l'invention, un outil étant en place pour l'ouverture du récipient, et
• la figure 5 comporte les figures 5a et 5b qui sont des vues schématiques partielles et en coupe d'un exemple de machine selon l'invention, lors de la mise en oeuvre du procédé de fermeture selon l'invention.

The invention will be better understood and other objects, advantages and characteristics thereof will appear more clearly on reading the description which follows, given with reference to the appended drawings which represent nonlimiting examples of embodiment of the invention and on which ones:

• FIG. 1 is a side view of a troncopyramidal container, closed by a lid according to the state of the art,
• FIG. 2 represents a half-section view of an example of a cover according to the invention,
• Figure 3 includes Figures 3a to 3c which are partial perspective views, with a cross section seen in section, of an example of a lid according to the invention and of a container in three stages of the closure process according to the invention,
• FIG. 4 is a partial perspective view, with a cross section seen in section, of a closed container with a lid according to the invention, a tool being in place for opening the container, and
• Figure 5 includes Figures 5a and 5b which are partial schematic views in section of an example of machine according to the invention, during the implementation of the closure method according to the invention.

The elements common to the different figures will be designated by the same references.

FIG. 1 shows a known truncopyramidal container, having a bottom 2 and close to the latter, a rod 3.

Such a container may also include a rod 4, at least in the corners, to allow separation easily stacked containers. A handle 5 can also be provided.

The container 1 is closed by a cover 6 conventionally used hitherto. It has a bottom, not shown in Figure 1, and a flange 7 which is extended by a series of legs 8 substantially perpendicular to the plane of the bottom of the cover. The free edge 9 of the legs is turned outward.

The cover 6 is fixed to the container 1 by blocking the tabs 8 under the edge of the container. A seal, not shown in Figure 1, is provided between the container 1 and the cover 6, around the opening of the container.

With reference to FIG. 2, an example of a cover 10 according to the invention essentially comprises: a bottom 11, a side wall 12 and a flange 13 whose concavity is turned towards the bottom 11. The flange ends with a rolled edge 14 towards the outside of the cover. This rolled edge gives a point of stiffness when the container is opened.

The cover 10 has no fixing lug, it and the rolled edge 14 which defines the periphery of the cover.

Preferably, a recess 30 is provided in the side wall 12 of the cover 10. This recess is advantageously provided to allow good stacking of the covers during their delivery and thus facilitate the automatic distribution of the covers.

Figures 3a to 3c will illustrate the closure process according to the invention.

Figure 3a partially shows a conventional metal container 1, for example of shape truncopyramidal. It has a free edge 15 rolled towards the inside of the container as well as a rod 4 to facilitate the separation of the stacked containers.

This container 1 has not undergone any modification compared to known containers. Furthermore, as will be seen below, the closure method according to the invention applies to containers of any shape, and in particular to cylindrical containers.

The container 1 is of the full opening type, that is to say that no element is present inside the container, at its opening. With this type of opening, the inner edge of the container is not capable of retaining part of the material contained in the container and it is therefore easily cleaned. This facilitates subsequent recycling of the container.

In the step of implementing the method illustrated in FIG. 3a, the cover 10 according to the invention is placed in the opening 16 of the container, a seal 17 being placed in the concavity of the rim 13. This step ends when the seal 17 comes into contact with the rolled edge 15 of the container 1.

Figure 3b shows the next step in implementing the method according to the invention, in which the seal 17 is compressed by exerting a force represented by the arrow F, in a direction substantially parallel to the walls of the container and directed towards its bottom.

The last step in implementing the closure process is illustrated in Figure 3c.

During this step, the force F is maintained to keep the seal 17 compressed and the cover 10 is fixed to the container by drawing the wall 12 of the cover 10 and the wall 18 of the container 1 which causes a deformation of these walls, towards the outside of the container. This stamping is carried out at points 19 distributed in an appropriate manner, by applying a force represented by the arrow F1, in a direction substantially parallel to the bottom 11 of the container and directed from the interior of the container towards its wall 18.

Thus, the method according to the invention ensures the closure of the container with a cover by stamping the latter directly on the container, without any other closing means being necessary.

The stamping points 19 are distributed in an appropriate manner, depending on the shape of the container.

In the case of a truncopyramidal container, the stamping points are preferably made in each of the four angles. Indeed, the corners constitute the most rigid parts. Furthermore, the wall of the container is, in general, slightly bent in these areas and these stamping points then contribute to ensuring the tightness of the container.

For this type of container, depending on the nature of the product it contains, it may be necessary to make stamping points on the long sides of the container. This is particularly the case when the internal pressure of the product contained in the container changes after filling (for example: hot or degassing product). These stamping points then ensure good retention of the cover.

In the case of a cylindrical container, the wall has a substantially identical stiffness at all points. The stamping points can thus be distributed regularly around the periphery of the container.

Preferably, the stamping is carried out according to segments, for example made up of points connected between them. This increases the strength of the closure. Furthermore, the cover can easily snap into the segments after opening the container. Indeed, stamping segments are more regular and precise than points.

The closure obtained by the process according to the invention has been the subject of numerous checks. The tests carried out have established that this closure has the level of quality commonly required, with regard to sealing and resistance to falling.

Furthermore, the method according to the invention makes it possible to modulate the quality of the closure. The tightness of the closure is obtained by crushing the seal. The compression which allows the seal to be crushed is adjusted so that sealing is ensured in all cases. By cons, during the implementation of the method according to the invention, the stamping can be adjusted so that the container has a greater or lesser resistance to impact and internal pressure.

The cover 10 used for implementing the method according to the invention only has a rolled edge at the periphery. No fixing lug is necessary to ensure the closure of the container, which improves the aesthetics of the closed container.

Figure 4 shows how to open a previously closed container with the method according to the invention.

The tapered end 21 of a tool 20, of the screwdriver type, is firstly introduced under the rim 13 of the cover 10.

The handle 22 of the screwdriver 20 is then rotated about its axis, which causes the lid to lift.

Preferably, when the container has corners, the screwdriver 20 is inserted under the rim 13 at level of a corner or bend. As soon as a corner is unlocked, the cover opens completely.

The opening of the container can thus be carried out in a single operation. This constitutes a considerable advantage compared to conventionally closed containers, such as that illustrated in FIG. 1, the opening of which can only be achieved by lifting each of the legs. The opening of such containers therefore requires as many operations as there are tabs, which is tedious for the user.

Furthermore, when the user wishes to close the container, it suffices to re-fit the cover 10 into the opening 16 of the container. This repositioning is carried out easily, ensuring a good seal.

This is another advantage of the lid according to the invention, compared to the closed containers in a conventional manner as illustrated in FIG. 1. After opening, the lid can be replaced on the opening of such a container but it does not provide its tightness only insofar as each tab 8 of the cover 6 is again blocked under the rim of the cover. These operations are never, in practice, carried out by the users. The container is therefore no longer waterproof, after opening, which generally leads to the degradation of the product it contains.

Reference is now made to FIG. 5 which shows an example of a machine according to the invention, during the implementation of the closing process.

Figure 5a corresponds to the step of the closing process, illustrated in Figure 3b.

The machine 23 comprises a plate 24 having a recess 25 at the periphery. The dimensions and the shape of the plate and the recess are chosen so that that the lower part 26 of the plate penetrates into the opening 16 of the container, while the step 25 is supported on the rim 13 of the cover 10.

Means not shown in Figure 5a are then actuated to press the plate 24 on the container. The compression force is illustrated by the arrow F. The value of this force is chosen so as to guarantee leaktightness whatever the thickness of the seal 17.

The machine 23 also includes means 26 for producing the stamping points 19 or segments. The means 26 consist of a plurality of punches 27 fixed on arms 28, themselves pivotally mounted on the plate 24, around an axis parallel to the plane of the plate. In FIG. 5b, only one arm 28 and one punch 27 are shown, the arm 28 being pivotally mounted about the axis 29.

The machine 23 comprises as many punches 27 as there are stamping points 19 provided. An arm 28 can carry one or more punches.

With reference to FIG. 5b which corresponds to the last step of the closing process, illustrated in FIG. 3c, the machine 23 maintains the compression force F and the drawing means 26 are actuated to produce a drawing at 19. For this , the means 26 pivot around the axis 29 and the punch 27 then exerts at 19 a force represented by the arrow F1.

Preferably, all the stamping points or segments are produced simultaneously, by appropriately actuating the stamping means 26.

As indicated previously, the importance of the locking can be adjusted by modifying the number of stamping points or segments, in particular to meet the requirements of the product contained in the container.

The reference signs inserted after the technical characteristics mentioned in the claims are for the sole purpose of facilitating the understanding of the latter and should in no way limit their scope.

Claims (7)

Method for closing a metal container (1) with a lid (10) comprising a bottom (11), a side wall (12) and a rim (13), according to which a sealing gasket (17) is placed periphery of the opening (16) of the container and, the cover (10) being placed on the container (1), pressure is applied to the cover (10) to crush the seal (17) between the container (1) and the rim (13) of the cover, characterized in that the seal (17) is blocked by stamping the side wall (12) of the cover on the container (1). Closing method according to claim 1, characterized in that the cover (10) is stamped on the container (1) at points (19) or segments distributed around the periphery of the container. Closing method according to one of claims 1 or 2, the opening (16) of the container being of substantially rectangular shape, characterized in that the stamping is carried out in each corner of the container. Closing method according to claim 3, characterized in that a stamping of the side wall (12) of the cover on the container (1) is also carried out in the large walls of the container and preferably, substantially at their center. Closing method according to one of claims 1 or 2, the opening (16) of the container being of substantially round shape, characterized in that the stamping of the lid (10) on the container (1) is carried out at points (19) or regularly distributed segments. Closing method according to one of claims 1 to 5, characterized in that the flange (13) of said cover (10) has a concavity facing the bottom (11) of the cover, in which said said is placed seal (17) and ends with an edge (14) rolled towards the outside of the cover. Machine for implementing the closing method according to one of claims 1 to 6, characterized in that it comprises means (24) for applying a compressive force to the cover when the latter is in place on the container and means (26) for stamping the cover (10) on the container (1).

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