EP0259292B1 - Closure lid for a metal can - Google Patents

Abstract

An airtight closing cover is produced which can be reused many times, is not deformable, is corrosion-resistant and is easily accessible to the point of a screwdriver, by covering a metal ring 7 with a sheath 15 in a resilient synthetic material and a peripheral shoulder 16 which, in the closed position, is crushed by the cover (9) against a folded back rim (13) of the ring (7) and therefore comprises a barrier to possible corrosive vapors. (FIG. 1).

Description

The present invention relates to a closure with a lid of a metal box composed of a body of substantially cylindrical or other shape, of a closure base crimped on the lower edge of the aforementioned body, comprising an inner ring crimped on the upper edge of the body, the free flank of the ring being stamped so as to present a circumferential groove whose inner wing is reinforced by a flange folded inwardly or outwardly in its extension, and a round cover whose marginal part has an annular profile convex in shape complementary to that of the aforementioned groove so as to be retained by tightening and a peripheral reinforcement rim.

It finds its main application in paint and varnish workshops, as a packaging element for paint products containing components liable to attack tinplate at places weakened by stamping.

The use for packaging and shipping of paint products of metal cans provided with a lid closure has been widespread for many years.

The metal boxes generally consist of a metal body of any shape and a round bottom crimped on the lower edge of the aforesaid body, so as to form the base of the aforesaid metal box.

The cover closure comprises a metal ring stamped in a grooved profile and set on the upper edge of the body of the above-mentioned box and a round cover, the marginal part of which has a circumferential rib intended to fit into the said groove ensuring a tight metal-to-metal contact on the sides of the groove.

The presence of a metal ring also aims to strengthen the resistance to crushing. It gives the lid closure sufficient rigidity to allow the stacking of many metal cans on top of each other, for example for handling on a pallet.

In addition, the cover allows the introduction of a screwdriver tip between the reinforcing bead and the crimped edge of the ring to remove the cover without damaging or deforming it.

The ring and the cover are profiled so that the peripheral bead of the cover is flush with the crimped edge of the ring, in the closed position of the box.

To strengthen the rigidity of the ring and improve the degree of tightness and reliability of the lid closure, provision is made to extend the inner wing of the groove of the ring, by an inner roll. or outside.

The drawdown of the inside or outside roll of the metal ring by stamping subjects it to extremely severe stresses. We therefore notice in the tinplate cracks due to the stretching of the sheets in the stamping presses. As these are tinned sheets possibly covered with a layer of varnish, it is not surprising to note that in certain critical places of the folded edge, the metal ring is devoid of protection and is directly subjected to the action corrosive to air, water and solvents contained in paint, varnish and other liquid or solid compositions packed in said metal cans.

It is therefore observed that in known metal cans, with American or tripletite closure, rust risks settling during prolonged storage periods, all along the folded rim.

In metal boxes with an interior roll, that is to say comprising an inner ring whose rim is folded in towards the inside of the box, the annular fold of the free edge of the groove has a circumferential gap in contact with the volume. inside the box, even with the lid on. The formation of rust inevitably leads to contamination of the paint product contained in said can.

In the case of an outer rolled edge consisting of a folded inwardly of the groove, the rust which begins to form from the cutting edge, moreover cracked, of the folded edge, spreads gradually along the rim to form an annular heap of rust against the contact line of the cover and the inner ring. When removing the cover, the contents of the canister are inevitably contaminated.

To remedy this, document DE-C-687.540 describes a closure for tinplate containers covered internally with a protective film held in place by an annular metallic closure ring crimped on the upper edge of the body of the box.

The tightness of the closure is improved by providing an annular seal in the peripheral fold of the cover.

The manufacture of a container provided with such a closure is difficult, due to the fact that the crimping of the annular metal closure ring on the body of the box and the fixing of the protective film on the rolled end of the ring are relatively laborious.

EP-A-0002337 also discloses a container with a lid closure in which the lid is provided with a recess in which the body of another container can be fitted, so as to allow them to be stacked in order to facilitate their storage during storage and transport.

The upper edge of the box body is provided with an annular closure ring made either of metal or of elastically deformable synthetic material. Such a container is however subject to corrosion when the metal closure ring is not protected by a protective jacket or is too weak against impact when the ring simply consists of an annular profile in synthetic material.

The problem posed consists in fixing, by crimping, a closure ring, not subject to corrosion, to the upper edge of the body of a metal box.

The present invention also aims to protect from corrosion the folded sides of a metal tin closure ring possibly protected with varnish. Such a ring is intended to receive the metal or plastic cover closing the metal box. It also aims to obtain an airtight closure of a container closed by a cover which must be able to be placed in turn in the groove of the closure ring and be removed a large number of times, without damage and without undesirably detaching under the action of an internal pressure, for example, the vapor pressure of the solvent or under the action of an impact.

As characterized in the following claims, the new element used in the cover closure according to the invention is a jacket made of preformed elastic synthetic material, snapped onto the inner face of the inner ring, provided internally with a shoulder peripheral surrounding the above-mentioned folded rim. This shirt is fixed to its outer periphery by crimping with the metal ring on the upper edge of the body of the metal box.

The metal ring is dressed with an annular synthetic material jacket provided with a peripheral shoulder, by snapping the shirt onto the inner face of the ring. During the latching, the peripheral shoulder of the shirt folds over the folded edge of the ring and forms with it an integral assembly, which is then crimped on the upper edge of the body of the metal box.

The elastic annular point is fixed to the metal ring by crimping said ring, on the upper edge of the body of the metal box.

According to a feature of the invention, the bead of the elastic seal is crushed against the folded rim of the ring, when the cover is tightened in the closed position, in the groove of the said metal ring.

The invention also relates to a method for making a metal box with a lid closure as described above.

To facilitate the manufacture of a metal box according to the invention, the jacket is fixed to the metal ring previously stamped but not yet crimped. The dressing of the ring is done by threading the peripheral bead on the folded edge of the ring and engaging the annular groove of the preformed shirt on the stamped profile of the ring. The elastic liner secured to the ring, follows the shapes of the stamped profile, can be crimped onto the upper edge of the body of the box in the same manner and with the same equipment as a ring not provided with an elastic liner.

The presence of a seal in elastic synthetic material according to the invention, on the metal ring allows to combine the advantages of a closure with a metal cover of the American or tripletite closure type, the advantages of a closure of plastic material, c '' i.e. waterproofing, repeated reuse and longevity even in corrosive environment.

In such a closure, the metal cover has in its marginal part, a convex annular profile which fits into a groove of complementary shape of a closure ring. The cover is in this way retained by a double metal-to-metal contact along each of the wings of the groove.

Other features and details of the invention will become apparent from the following detailed description, in which reference is made to the accompanying drawings which show an embodiment of a cover closure according to the invention.

In these drawings:

• Figure 1 is a partial sectional view of a metal box with a lid closure according to the invention;
• Figure 2 is a sectional view of a canister provided with an inner protective container; and
• Figure 3 is a view similar to Figure 1 of a metal box whose closure ring is provided with a flange folded down on the inner side of the box.

In these drawings, the same reference notations designate identical or analogous elements.

As illustrated in FIG. 1, a metal box generally designated by the reference numeral 1, is formed of a substantially cylindrical body 2, consisting of a tin sleeve crimped along a generator 3 of the cylinder and of a circular closure base 4 set on the lower edge 5 of the above-mentioned body 2.

The upper part of the metal box 1 consists of a cover closure 6.

This closure 6 comprises an inner metal ring 7, set on the upper edge 8 of the body 2 and a metal cover 9. The free side of the ring 7 is stamped according to the predetermined profile.

The ring 7 is stamped so as to present a circumferential groove 10 having two wings 11,12 intended to enclose a convex profile 10ʹ, of corresponding shape of the metal cover 9.

The inner wing 12 of the groove 10 of the ring 7 above is reinforced by a rim 13. This rim 13 is folded either on the side of the groove 10 (Figure 1), or on the inside of the box (Figure 3). This folded rim 13 is intended to make the profile of the ring 7 more rigid so as to securely enclose the cover 9.

This cover 9 is generally round. It consists of a sheet formed by stamping with a press. The marginal part of the cover 9 has a convex annular profile with a shape complementary to that of the groove 10 of the metal ring 7. The peripheral edge of the cover 9 is folded down so as to form a peripheral rim 14.

The ring 7 and the cover 9 are profiled so that in the closed position of the box, the peripheral rim 14 of the cover 9 is flush with the crimped edge 8 of the ring. There remains between the cover 9 and the closure ring 7 a space in which one can introduce the point of a screwdriver not shown with the help of which one can lift the cover and open the metal box.

The convex annular profile of the cover 9 engages in the rib of complementary shape of the closure ring 7. The sides of the annular profile of the cover 9 are in this way clamped by a double metal-to-metal contact along each of the wings of the rib constituting the groove 10 of the closure ring 7.

According to the invention, the inner face of the ring 7 is covered with a jacket 15 of elastic synthetic material. The jacket 15 is provided internally a peripheral shoulder 16 extending the lip of the inner flank of the annular fold of the shirt.

This jacket 15 is mounted on the closure ring 7, after the stamping of the ring but before crimping on the upper edge of the body 2 of the box. The peripheral shoulder 16 of the jacket 7 rests on the folded edge 13 of the ring 7 and the jacket covers the convex annular portion of the stamped profile of the ring 7.

The ring 7 dressed in the elastic jacket 15 is fixed to its outer periphery by crimping on the upper edge 8 of the body 2 of the metal box 1.

The elastic shirt 15 follows the shapes of the stamped profile. In the closed position, the cover 9 engages by its convex annular profile in the groove 10 of complementary shape to the closure ring 7.

The annular profile forms a convex rib which fits into the aforementioned groove 10, so as to be clamped along the side walls by the lateral wings 11,12 of the groove 10. A double metal-to-metal contact is obtained which retains securely the cover 9 and prevents any untimely removal of said cover.

In a particular embodiment according to the invention, the body and the bottom of the metal box are internally covered with a lining of molded, injected or thermoformed synthetic material forming a container 17 whose upper edge is crimped with the metal ring 7 on the top edge 8 of the body 2 of the metal box 1 (Figure 2).

The invention also relates to a method for manufacturing a metal box provided with a lid closure according to the invention.

After stamping the metal ring 7 with an elastic jacket 15 preformed in synthetic material. The jacket 15 is provided, along its inner edge with a peripheral shoulder 16.

To cover the closure ring 7, before crimping, the preformed shirt 15 is applied against the face of the ring 7 facing the inside of the box and the peripheral periphery of the shirt 15 is folded over the folded edge of the ring 7. The assembly formed by the metal ring 7 and the said jacket 15 is then crimped onto the upper body of the body 2 of the metal box 1.

The invention is not limited to metal cans formed of a substantially cylindrical body, or it also relates to metal cans of any shape provided with a closure with a round cover.

Claims (3)

1. Lid closure for a metal can (1) consisting of a body of any shape (2), a sealing bottom (4) crimped onto the bottom rim (5) of the above mentioned body (2), comprising an inner ring (7) covered on its internal face with a lining (15) of synthetic material and crimped onto the top rim (8) of the body (2), the free side of the ring being dished, so as to present a circumferential recess (10), the inner lip of which is reinforced by a shoulder turned down in its extended part, and a round lid (9), the peripheral part of which has a convex annular profile (10') with a shape complementary to that of the above mentioned recess (10) so as to be held by gripping, and a peripheral shoulder (14), characterised in that the lining (15) of preformed flexible synthetic material is provided on the inside with a peripheral collar (16) passing round the above mentioned turned down shoulder and is fixed at its outer circumference by crimping with the ring (7) onto the top rim of the body (2) of the metal can (1).
2. Closure according to claim 1, characterised in that in the sealing position, the cover (9) squeezes the collar (16) of the above mentioned flexible lining (15) against the turned down shoulder (13) of the ring (7).
3. Method for making a lid closure for a metal can (1) according to either of the preceding claims, consisting of a body with any shape (2), a sealing bottom (4) crimped onto the bottom rim (5) of the above mentioned body (2), comprising an inner metal ring (7) which is covered on its internal face with a lining (15) of synthetic material and which is crimped onto the top rim (8) of the body (2), by dishing the free side of the ring so as to form a circumferential recess (10), the inner lip of which is reinforced by a shoulder turned down in its extended part, and a round lid (9), the peripheral part of which has a convex annular profile (10') with a shape complementary to that of the above mentioned recess (10) and a peripheral shoulder (14), characterised in that the metal ring (7) is covered with an impervious annular flexible lining (15) of synthetic material provided with a peripheral collar (16), by pressing the lining (15) against the internal face of the ring (7), turning down the peripheral collar (16) over the turned down shoulder of the ring (7), and the lined metal ring of the said joint is crimped onto the top rim (8) of the body (2) of the metal can (1).

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