IES86168B2 - A plastic container with a lid - Google Patents

Abstract

A plastic container comprising a cylindrical body and a lid for hermetically closing the container, the inner face of the wall of the container being provided with a ring-shaped rim, the lid being provided with engagement means that cooperate with the rim of the container to retain the lid in a closed position. The rim is a radically projecting locking wedge having a tip surface and an upper and a lower engagement surfaces, and the engagement means comprise a retaining annular groove, narowing inwards and having a bottom surface and opposing upper and lower engagement surfaces, the mating engagement surfaces of the rib and of the groove being designed to ensure, when the lid is placed in its closed position, that the locking wedge is squeezed into the groove and leaving a space (z) between the bottom surface of the groove and the tip surface of the locking wedge. <Figure 1>

Description

DESCRIPTION “A plastic container with a lid” Technical Field of the Invention The invention relates to a cylindrical plastic container with a lid. The container being especially suitable for storing semi-liquid or liquid products such as water based paints during months before its first opening.

Background of the invention Typically, plastic containers used for semi-liquid or liquid products such as water based paints are provided with a rim, extending around the outside wall of the container, for attachment of the lid.

Conventionally, the lids have a peripheral portion comprising at least one annular flange that cooperates with the rim of the container for retaining said lid in a closed position. The lid is applied to the container by pressing the lid downwards on to the said container, whereby the flange of the lid snaps under the rim of the container.

This snap-on-lid closure system requires that the rim of the container and/or the peripheral portion of the lid to be pressed over said upper portion of the lateral wall of the container be elastically distorted during the closure operation. This means that the profiles of the container and of the lid interfere. This interference is a factor that subsequently affects the tightness of the closure.

An improved design for containers has been described in documents US 5839604 and W02009/043687, comprising a cylindrical body provided with an inner rim projecting from the inner surface of the wall of the container, provided with a ring-shaped rim the function of which is to cooperate with a respective projection or flange arranged in the lid for retaining the lid in the closed position.

However, there is a desire to increase the production tolerances -2S86168 when producing this design and the main objective of the present invention is to disclose a container which maintains the long-time leakproofness even when produced with larger tolerances.

Explanation of the Invention The plastic container of the invention is of the type comprising a cylindrical body, having a wall that extends around an axis (CL), and a lid for hermetically closing the container, the inner face of the wall of the container being provided, at a short distance below its top edge, with a ring-shaped rib, the lid comprising a round central portion and a peripheral portion provided with a first downward section joined to a second upward section which is configured for being at least partially applied on the upper portion of the inner face of the wall of the container, the upward section being provided with engagement means that cooperate with the rib of the container to retain the lid in a closed position.

In its essence, the container is characterized in that the rib is a radial projecting locking wedge having a tip surface and an upper and a lower engagement surfaces; and in that the engagement means comprise a retaining annular groove, narrowing inwards and having a bottom surface and opposing upper and lower engagement surfaces, the mating engagement surfaces of the rib and of the groove being designed in such a way that, when the lid is placed in its closed position, the locking wedge is squeezed into the groove leaving a space between the bottom surface of the groove and the tip surface of the locking wedge.

Advantageously, this solution permits not only to distribute the contact force between the container and the lid but also to maximize the vertical component of said force and minimize the radial component required for an efficient seal over time.

Preferably, in the assembled position, the upper engagement surfaces of the locking wedge and of the groove contact each other along a first contact line only. -3To that end, in one embodiment the upper engagement surface of the groove is perpendicular to the axis (CL) while the mating upper engagement surface of the locking wedge is downward sloped.

More preferably, in the assembled position, the lower engagement surfaces of the locking wedge and of the groove contact to each other also along a second contact line.

According to another feature of the invention, the lower engagement surface of the groove is downward sloped at an angle relative to a plane perpendicular to the axis (CL) while the mating lower engagement surface of the locking wedge is perpendicular to the axis (CL) or downward sloped relative to said plane in a degree less than the lower engagement surface of the groove.

The first contact line may be located at an outer upper edge of the groove while the second contact line may be located at a distal lower edge of the locking wedge.

In one arrangement according to the invention, the container further comprises a resilient sealing member, which extends around the entire annular groove of the lid between the bottom surface of the annular groove and the tip surface of the locking wedge.

Brief Description of the Drawings Fig. 1, is a cross section view of the upper portion of a container and the peripheral portion of a lid, in its assembled position, according to the invention; Fig. 2, is a detailed view of the area of the Fig. 1 delimited with dotted lines; and Fig. 3, is a partial view of the Fig. 1 showing the decomposition of the forces Fu and Fd acting over the lid.

Detailed Description of the Invention Fig. 1 shows the profiles of the upper portion of the wall 8 of a cylindrical container 2 and a portion of a lid 3, especially designed to fit the -4container 2, according to the invention.

The lid 3 comprises a flat round central portion 6 and a peripheral portion provided with, from the inside towards the outside, a first downward section 7a joined to a second upward section 7b having an uneven configuration. The first downward section 7a and the second upward section 7b are connected by means of a circumferential joining portion 7c that can optionally be of a reduced thickness compared to the thickness of the said downward and upward sections 7a and 7b, to provide certain flexibility to the lid to resist impact and possible over pressure in the container.

In the embodiment of Fig. 1, the uppermost end of the lid 3 extends outwardly forming a straight segment to cover the top edge 5 of the container 2 when said lid 3 is applied to the container.

The wall 8 of the container 2 has an upper rim 14 extending 15 inwards. This rim 14 is thicker than main portion of the wall 8 and defines an inner face 4 of the wall 8 having a ring-shaped rib in the form of a radial projecting locking wedge 9 which will fit into the groove 10 of the lid 3 when said lid 3 is placed in its assembled position. A container 2 like this can be obtained for example following the method described in patent document US 457a2399.

The locking wedge 9 (see Fig. 2) has a tip surface 9a and upper and lower engagement surfaces 9b, and 9c having specific slopes in relation to mating engagement surfaces provided in the second upward section 7b of the lid 3.

Specifically, said upward section 7b of the lid 3 is provided with engagement means that cooperate with the locking wedge 9 of the container 2 to retain the lid 3 in a tight closed position. Fig. 2 illustrates that these engagement means comprise a retaining annular groove 10 narrowing inwards and having a bottom surface 10a and opposing upper and lower engagement surfaces 10b, 10c. The mating engagement surfaces of the locking wedge 9 and of the groove 10 are designed to ensure, when the lid 3 is placed in its closed position, that the locking -5wedge 9 is squeezed into the groove 10, leaving a space (z) between the bottom surface 10a of the groove 10 and the tip surface 9a of the locking wedge 9.

Anyway, the provision of a wedge profile and a corresponding narrowing groove result in that the force conventionally applied over a lid by the blunt end of a common rib provided in the container’s wall is converted here into forces perpendicular to the upper and lower engagement surfaces of the locking wedge 9. In other words, the radial component of the contact force between the container and the lid is here significantly diminished in favor of the vertical component of said force.

Fig. 3 shows in detail the decomposition of the contact forces Fu and Fd applied by the locking wedge 9 over the lid 3, specifically over the upper and lower engagement surfaces 10b and 10c of the annular groove 10 of the lid 3.

Forces Fu and Fd have been decomposed into a vertical component Fuy and Fdy, parallel to the center axis CL of the container 2, and into a horizontal or radial component Fux and Fdx, respectively, perpendicular to said axis CL. Fig. 3 shows on the one hand how the contact forces that will guarantee the tightness of the closure is essentially vertical and on the other hand that there are two contact areas between the lid and the container that wiil prevent the leakage of the product.

It has to be noted that in the assembled position, the upper and lower engagement surfaces 9b and 9c of the locking wedge 9 do not match with the corresponding upper and lower engagement surfaces 10b and 10c of the groove 10, so that in the assembled position each pair of facing engagement surfaces contact each other along respective first and second lines of contact 11 and 12 respectively, as shown in Fig. 2. This reduction of the contact areas between the container 2 and the lid 3 increases the pressure exerted by the container 2 to the lid 3 or vice versa, as the value of the pressure is inversely proportional to the contact area between the parts in contact.

In effect, the upper engagement surfaces 9b; 10b of the locking -6wedge 9 and of the groove 10 contact to each other along a first contact line 11 and the lower engagement surfaces 9c; 10c of the locking wedge 9 and of the groove 10 contact to each other along a second contact line 12.

In the preferred embodiment of Figs. 1 and 2, the upper engagement 5 surface 10b of the groove 10 is essentially perpendicular to the axis CL while the mating upper engagement surface 9b of the locking wedge 9 is downward sloped. Simultaneously, the lower engagement surface 10c of the groove 10 is downward sloped relative to the plane 13 perpendicular to the axis CL while the mating lower engagement surface 9c of the locking wedge 9 is essentially perpendicular to the axis CL.

As a result, the first contact line 11 is located at an outer upper edge of the groove 10 and the second contact line 12 is located at the lower corner of the locking wedge 9.

The sloped angle c makes it easier to remove the lid from the 15 container by e.g. a screwdriver when needed.

Claims (5)

1. - A cylindrical plastic container (2), having a wall (8) that extends around an axis (CL), and a lid (3) for closing the container, the inner face (4) of the wall (8) of the container being provided, at a distance below its top edge (5), with a ring-shaped rib, the lid (3) comprising a round central portion (6) and a peripheral portion provided with a first downward section (7a) joined to a second upward section (7b) which is configured for being at least partially applied on the upper portion of the inner face (4) of the wall of the container (2), the upward section (7b) being provided with engagement means that cooperate with the rib of the container to retain the lid in a tightly closure position, characterized in that - the rib is a radially projecting locking wedge (9) having a tip surface (9a) and an upper and a lower engagement surfaces (9b, 9c); and in that - the engagement means comprise a retaining annular groove (10), narrowing inwards and having a bottom surface (10a) and opposing upper and lower engagement surfaces (10b, 10c), the mating engagement surfaces of the rib and of the groove being designed such that ensure, when the lid is placed in its closure position, that the locking wedge (9) is squeezed to an assembled position into the groove (10) and leaving a space (z) between the bottom surface (10a) of the groove (10) and the tip surface (9a) of the locking wedge (9).

2. - A plastic container (2) according to claim 1, characterized in that the first downward section (7a) and the second upward section (7b) are connected by means of an intermediate joining portion (7c) having at least one section (15) of a reduced thickness compared to the thickness of the said downward and upward sections (7a and 7b). -83. - A plastic container (2) according to claim 1 or 2, characterized in that the upper engagement surface (10b) of the groove (10) is perpendicular to the axis (CL) while the mating upper engagement surface (9b) of the locking wedge (9) is downward sloped, and in that the upper 5 engagement surfaces (9b; 10b) of the locking wedge (9) and of the groove (10) contact to each other along a first contact line (11) when the lid is in the closure position.

3. 4. - A plastic container (2) according to any of claims 1 to 3, 10 characterized in that, in the assembled position, the lower engagement surfaces (9c; 10c) of the locking wedge (9) and of the groove (10) contact to each other along a second contact line (12).

4.

5. - A plastic container (2) according to claim 4 when dependent, 15 directly or indirectly, on claim 3, characterized in that the first contact line is located at an outer upper edge of the groove; and in that the second contact line is located at a distal lower edge of the locking wedge.