Closure system for reusable containers and container

Abstract

A closure system for reusable containers, comprising a lid (2) attachable to an access opening (3) of a cylindrical container (1) made of biodegradable material, and a clamp (4) configured for hermetically sealing the lid (2) to the container (1) by pressure, wherein the lid consists of a body of moldable plastic material formed by a base section and a peripheral side flange configured to fit the access opening of the container, characterized in that the side flange of the lid is formed by: - a first inner section (8) with a U-shaped cross-section configured to fit into the inner face of the container, and - a second outer section (11) defined by a region with a lower height than the first inner section (8), the region having an inverted U-shaped cross-section dimensionally configured to embrace a fold section extending peripherally outward at the access opening (3) and an upper section of the wall

Description

Closure system for reusable containers and container OBJECT OF THE INVENTION The present invention relates to a closure system for reusable containers, as well as a container provided with such a closure system. The present invention falls within the field of storage containers, and more specifically within industrial cardboard drums or containers with a closing lid, intended for the transport and storage of solids or granular materials. In particular, the invention relates to an improved drum lid that meets regulatory and functional requirements, while also offering advantages in storage (stacking) and sustainability in its manufacture. BACKGROUND OF THE INVENTION In commonly used drums, especially those made of cardboard, the lid is a critical structural element, as it must guarantee a watertight seal, mechanical resistance to impacts, and the stability of the assembly during storage and transport. However, conventional lids have limitations when subjected to drop tests required by current regulations for drums without reinforcing rings. Under these conditions, the lid-drum assembly tends to deform, causing the lid to dislodge and compromising the integrity of the seal. This deficiency highlights the need to increase the structural rigidity of the assembly without compromising its functionality or significantly increasing its weight or production cost. Furthermore, existing locking systems do not allow for stable stacking of the drums, which hinders storage and transport operations and increases the risk of tipping or displacement of the containers during handling. The inability to stack the containers or drums represents a significant practical limitation for logistics operators and industrial users who need to optimize available space. Furthermore, the applicant is not currently aware of an invention that has all the features described in this specification. DESCRIPTION OF THE INVENTION The present invention has been developed in order to provide a closure system that is configured as a novelty within the field of application and solves the aforementioned drawbacks, also providing other additional advantages that will be evident from the description that follows. It is therefore an object of the present invention to provide a closure system for reusable containers, of the type comprising a lid attachable to an access opening of a cylindrical container made of biodegradable material, and a clamp configured for airtight closure of the lid to the container by pressure, wherein the lid consists of a body of moldable plastic material that is formed by a base section and a perimeter side flange configured to fit the access opening of the container. In particular, the invention is characterized by the fact that the side rim of the lid is formed by: - a first inner section with a "U" shaped cross-section configured to be fitted into the inner face of the container, and - a second outer section (11) that is defined by a region with a lower height than the first inner section (8), the region having an inverted "U" shaped cross-section that is dimensionally configured to embrace a fold section that extends outward peripherally at the access opening (3) and an upper section of the container's side wall. Advantageously, an outer face of the first inner section, which is intended to be in contact with the inner face of the container's side wall, can include a plurality of ribs distributed radially along its entire length. According to the invention, the base section of the lid has a peripheral annular region that is at a height level elevated above the upper level of the side rim. According to the invention, the clamp has an upper annular section and a lower flange section that extends peripherally and downwards, configured to wrap around the second outer section of the lid, the clamp being made of a metallic material. Preferably, the height of the first section is at least one third of the height of the second section of the lid body. Another object of the invention is to provide a container having a body made of a biodegradable material consisting of a cylindrical body defined by an access opening, a side wall, and a base, which define an interior storage region, including in the inlet opening a locking system as described above. According to the invention, the inner region includes a reinforcing structure with a disc-shaped form located at the base. Preferably, the reinforcement structure has a honeycomb configuration. According to the invention, the side wall of the container may have a lower fold, the container material being particularly biodegradable and consisting of cardboard or cellulose-based material. Thanks to these structural features of the lid, greater rigidity and mechanical resistance are provided, allowing the drum and lid assembly to successfully withstand the drop tests established by applicable regulations (ADR, which corresponds to the Agreement on the International Carriage of Dangerous Goods by Road). This improvement reduces deformation at the closure and prevents the lid from detaching after an impact, guaranteeing the integrity of the contents and increasing safety during the transport and handling of the drums. On the other hand, the upper geometric configuration of the lid is designed to allow for the stable stacking of several drums, so that the bottom of each container fits precisely onto the lid of the one below. This feature facilitates orderly and safe storage, optimizes available space in warehouses or transport vehicles, and helps reduce accidents caused by tipping or displacement during handling. Also, the possibility of manufacturing the lid with recycled plastic material from packaging waste. Overall, the invention offers a solution that combines structural strength, logistical functionality and environmental sustainability, responding to the new technical, regulatory and commercial demands of the industrial drum sector. Another equally advantageous aspect is that this system facilitates the stacking of containers on top of each other in a more stable manner, thus improving safety in storage and transport. Other features and advantages of the locking system of the present invention will become evident from the description of a preferred, but not exclusive, embodiment, which is illustrated by way of non-limiting example in the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial exploded perspective view of the container and the closure system of the invention; Figure 2 is a partial perspective view of the container closed by the closure system of the invention; Figure 3 is a top perspective view of an embodiment of the lid that forms part of the closure system of the present invention; Figure 4 is a bottom perspective view of the lid that forms part of the locking system; Figure 5 is a partially sectioned perspective view of the lid depicted in Figures 3 and 4; Figure 6 is a sectioned elevation view of the lid; Figure 7 is a cross-sectional detail view of the lid flange indicated in Figure 6 with reference B; Figure 8 is a partial elevation detail view of two containers according to the invention in a stacked condition; Figure 9 is a partial cross-sectional view of the bottom of a container according to the invention; and Figure 10 is a plan view of a second embodiment of the lid that forms part of the closure system according to the invention, which includes an enlarged detail view. DESCRIPTION OF A PREFERRED EMBODIMENT In view of the aforementioned figures and in accordance with the numbering adopted, an example of a preferred embodiment of the invention can be observed, which comprises the parts and elements indicated and described in detail below. As shown in Figures 1 and 2, in a preferred embodiment of the invention, the closure system is designed for use on reusable cylindrical containers (1) made from biodegradable materials, such as structural cardboard or cellulose-based materials. The system comprises a lid (2) that attaches to the access opening (3) of the container (1) and a clamp (4) configured to exert perimeter pressure, ensuring a hermetic seal between the two elements. With particular reference to figures 3 to 5, the lid (2) is formed from a body of moldable plastic material, preferably obtained by injection molding or thermoforming, and comprises a base section (6) and a peripheral side rim (7) intended to fit precisely to the mouth (3) of the container (1). As can be seen in figures 6 and 7, the lateral flange (7) has a configuration designed to improve the sealing and stability of the assembly, being formed by two different sections, in the direction from inside to outside, as follows: a first inner section (8) with a substantially "U" shaped cross-section, defining a first cavity (14), configured to fit into the inner face (9) of the side wall (10) of the container (1); and a second outer section (11) defined by a region (12) of lower height than the first section (8), which has a cross-section that adopts an inverted "U" shape, defining a second cavity (16). Thus, the second cavity (16) of the second outer section (11) is sized to simultaneously embrace a perimeter fold (13) that protrudes outwards at the mouth (3) of the container (1) and an upper section of the side wall (10), contributing to a firm and watertight closure. On the outer face of the first inner section (8) there is a plurality of elongated ribs (15) distributed equidistantly and radially along its entire length. These ribs (15) increase the friction between the lid (2) and the inner surface of the side wall (10) of the container (1), reinforce the rigidity of the assembly, and absorb the stresses resulting from the pressure exerted by the clamp (4). The base section (6) of the lid (2) features a peripheral annular region (17) positioned at a higher level than the upper plane of the side flange (7), which increases vertical compression resistance and improves the stacking capacity of the assembly. Thanks to this configuration, the bottom of an upper container can partially fit into the lid (2) of the lower container, ensuring stable stacking during storage or transport. The airtight seal is completed by means of the clamp (4), preferably metallic, comprising an upper annular section (40) and a lower flange (41) extending downwards and arranged around the perimeter. This lower flange (41) encloses the second outer section (11) of the lid (2), applying uniform radial pressure that ensures a watertight seal without damaging the biodegradable material of the container (1). In a particular configuration, the height (h1) of the second section (11) is one third of the total height (h2) of the lid body (2), ensuring a firm hold and a balanced distribution of stress between the edge of the container (1) and the lid (2). As can be seen more clearly in Figure 9, the container (1) comprises a cylindrical body with a defined base (22) and access opening (3), featuring a side wall (10) with a lower fold (24) that enhances its structural stability. A disc-shaped reinforcing structure (19) is located in the interior region (25) of the container, parallel to and at a distance from the base (22). This reinforcing structure (19) has a honeycomb configuration, providing high resistance to vertical compression and maintaining the geometry of the container (1) during use and stacking. Figure 10 shows an alternative embodiment of a lid (2) that forms part of the closure system, whose parts common to the previous example have the same numerical references. In this case, the cavity (14) present in the first inner section (8) is provided with a plurality of small ribs (18) arranged equidistantly along the entire perimeter length, which provide greater rigidity to the lid assembly and limit its deformation in case of a fall of the container. The details, shapes, dimensions and other accessory elements used in the manufacture of the closure system of the invention may be conveniently replaced by others that do not depart from the scope defined by the claims included below.

Claims

1. A closure system for reusable containers, comprising a lid (2) attachable to an access opening (3) of a cylindrical container (1) made of biodegradable material, and a clamp (4) configured for hermetically sealing the lid (2) to the container (1) by pressure, wherein the lid consists of a body of moldable plastic material formed by a base section and a peripheral side flange configured to fit the access opening of the container, characterized in that the side flange of the lid is formed by: - ​​a first inner section (8) with a "U"-shaped cross-section configured to fit into the inner face of the container, and - a second outer section (11) defined by a region with a lower height than the first inner section (8),1. The region has an inverted "U" shaped cross-section dimensionally configured to embrace a fold section extending outwardly around the access opening (3) and an upper section of the container's side wall.

2. The closure system according to claim 1, wherein an outer face of the first inner section (8) of the lid (2), intended to contact the inner face of the container's side wall, includes a plurality of ribs (15) distributed radially along its entire length.

3. The closure system according to claim 1, wherein the base section (6) of the lid (2) has a peripheral annular region (17) that is at a height level elevated above the upper level of the side flange (7).

4. The closure system according to any of the preceding claims,wherein the clamp (4) has an upper annular section (40) and a lower flange section (41) extending peripherally and downwards, configured to enclose the second outer section of the lid (2), the clamp (4) being made of a metallic material.

5. A closure system according to claim 1, wherein the height (h1) of the second section (11) is one-third of the total height (h2) of the lid body (2).

6. A closure system according to claim 1, wherein the cavity (14) is provided with a plurality of ribs (18) arranged equidistantly along its entire perimeter length.

7. A container (1) having a body made of a biodegradable material, consisting of a cylindrical body defined by an access opening (3), a side wall (10), and a base (22), which define an interior storage region (25).including in the inlet opening (3) a locking system according to any of claims 1 to 6.

8. Container (1) according to claim 7, wherein the inner region (25) includes a reinforcing structure (19) with a disc-like shape located at the base (22).

9. Container (1) according to claim 8, wherein the reinforcing structure (19) has a honeycomb configuration.

10. Container (1) according to claim 7, wherein the side wall (10) has a lower fold (24) located below its base.

11. Container (1) according to any of claims 7 to 10, wherein the biodegradable material consists of cardboard or is cellulose-based.