TITLE

Container in the form of a receptacle and removable lid that has a collar and method for applying the lid

TECHNICAL FIELD

The present invention relates to a container in the form of a receptacle and removable lid that has a collar according to the preamble to the following claim 1.

The present invention also relates to a method for applying the lid on the receptacle according to the preamble to the following claim 5.

BACKGROUND ART

For a lid to form a tight seal on an associated receptacle, there are sealing surfaces that make contact with each other and can start to form a seal before the lid is completely applied. Accordingly, an overpressure can arise inside the container, that counteracts the force that is attempting to hold the lid on. This can make it more difficult to apply the lid and there is also a risk of the lid coming loose unintentionally, particularly with careless handling. In addition, both the receptacle and the lid can be deformed during the application. Other disadvantages associated with the presence of an unnecessarily large volume of air can be that the medium that is contained, for example paint, can deteriorate more quickly with time.

Attempts have previously been made to solve the above disadvantage by removing air by means of a vacuum pump that is connected to a lid with a non-return valve and by extracting the enclosed air by means of this pump, see for example US 5806704. This involves relatively expensive equipment and a relatively expensive lid design, which is not desirable in industries where packaging and also the product content are cost-sensitive.

DISCLOSURE OF INVENTION

The object of the present invention is to produce a container, in the form of a receptacle and removable lid, that eliminates the abovementioned disadvantages.

The said object is achieved by means of the container according to the invention, that has the characteristics that are described in the following claim 1.

The said object is achieved by means of the method, that has the characteristics that are described in the following claim 5.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in greater detail in the following in the form of an embodiment, with reference to the attached drawings in which

Figure 1 shows a vertical section through a container according to the invention, with the lid applied on the associated receptacle,

Figure 2 shows an enlarged section through the upper edge of the receptacle with similarly a section through the lid, viewed from the outside,

Figure 3 shows an enlarged section of the lid separately, viewed from the inside,

Figure 4 shows an enlarged second section of the lid separately, viewed from the inside, while

Figures 5-9 illustrate, by means of vertical sections, the method according to the invention for applying the lid.

MODE FOR CARRYING OUT THE INVENTION

The container according to the invention is, for example, intended for storage and transportation of liquid products, for example paints, and is shown in its entirety in Figure 1 , that shows a centrally vertical section through the axis of symmetry 1 of the container, around which the container in the example is symmetrical when it rotates. The container consists of a receptacle 2 with a lid 3. In the example, the receptacle and the covering part of the lid are made of a relatively thin plate, normally tin plate that is an even thickness and is produced from a flat or rolled sheet material, for example steel plate with a tin-plated surface on at least one side and possibly painted on at least the outside. The plate can also be painted on the inside to give increased protection against corrosion. The thickness of the plate is for example 0.1- 1.0 mm, normally 0.1-0.5 mm. In order to reduce the amount of material required and hence the cost and weight, for paints, for example, a relatively small thickness of material is selected but is given a shape that has a relatively good shape permanence, particularly at the edges.

At the bottom, the receptacle has a base 4 that is usually flat and is attached to an outer wall 5 that extends upwards all around, and is normally slightly conical or possibly cylindrical. The joint with the base is made, for example, in a conventional way by folding the edges and soldering, so that a tight joint is obtained. The outer wall 5 is joined by means of a plate seam (not shown). At the top, the outer wall becomes a circular peripheral edge 6 of an opening, which edge encompasses an opening in the receptacle, which opening is normally closed by means of the lid 3. Similarly, the lid has a peripheral edge 8 that is intended to form a sealed joint with the edge of the opening in the receptacle and to hold the lid closed.

The opening 6 in the receptacle is shown most clearly in Figure 2 and is formed of an elongated part of the outer wall 5. This means that, in addition to the part that is straight in the section that forms the outer wall, the same steel plate that is cut to form the outer wall 5 has an extension that forms the edge of the opening and also an additional part that has a function that will be described in greater detail below.

The edge 6 of the opening in the receptacle, like the rest of the receptacle, can comprise a previously-known construction and, in the example shown, is described in greater detail in the document SE-B 525 814. Its main construction is described here with reference to Figure 2 for the purpose of providing greater understanding of the whole function of the container. The edge 6 of the opening in the receptacle is formed by the top of the outer wall 5 being bent in an outward direction to form a rounded crown 9 and it changes from there to an outer edge 11 that is angled inward toward the outside 10 of the wall with a suitably selected angle, which edge has the shape of an inverted truncated cone. This part is advantageously connected at the bottom to the outer wall of the receptacle 10 so that the outer edge 11 is supported against the outer wall of the receptacle, more specifically against its outside.

The extension of the plate changes into a part that is curved outward by a combination of bends and an edge 12 that is rolled inward in a flange 13 that is arranged a short distance below the edge 6 of the opening in the receptacle. In the example shown, the flange 13 is provided with three main surfaces, namely a flange surface 14 that projects radially outward and faces essentially upward, that changes into a flange surface 16 that faces radially outward, which flange surface is cylindrical in the example shown, but can be slightly convex, and that changes from there, via a lower bent rounded edge 17, to a flange surface 18 that faces downward and that terminates in the said rolled edge 12. This is suitably in contact with the outside of the outer wall in order to provide support and stability for the flange 13, that has essentially a fastening function for the lid 3, that will be described in greater detail below.

The lid 3 has a construction that is characteristic for the invention, that is shown more clearly in Figures 2-4. The lid is of the clamp-fit type, which means that the edge of the lid surrounds the edge 6 of the opening in the receptacle, that is, it extends beyond this in a radial direction and projects downward below the crown 9 of the edge of the opening. The edge 8 of the lid has namely a collar 19 that projects downward outside the edge 6 of the opening in the receptacle in such a way that the lid is held securely and forms a tight seal. More specifically, the edge 8 of the lid 3 has a circular

flange 20 that projects upward and extends around the crown 9 of the edge 6 of the opening in the receptacle. The flange 20 consists of an inner wall 21 , an upper wall 22 and an outer wall 23. These walls extend inside, above and outside the upper edge 6 of the receptacle respectively. On the inside, that is on the underside of the upper wall 22 of the flange, a channel 47 is formed facing toward the edge 6 of the opening in the receptacle, in which channel a seal 24 is arranged that is made of a suitable flexible material, such as an elastomer, for example a polymer, such as PVC, or a rubber material for forming a seal between the rounded crown 9 of the receptacle and the edge of the lid. From the outer wall 23, the plate material is bent outward from the upper edge 6 of the receptacle to an outer flange 25, that consists of a flange 26 that projects outward in a radial direction and becomes at this point a folded part 27, in this case a part that is folded upward with a rounded transition 28. The flange 26 that projects radially outward and the folded part 27 form a fastening for the collar 19 of the lid 3, which collar is made of a plastic material, for example polypropylene, that is flexibly resilient and can be produced, for example, by injection molding directly onto the peripheral edge of the closing part 46 of the lid which, in the example illustrated, is made of metal plate.

The collar 19 forms an upper peripheral flange 29 that projects upward, and the securing part 26, 27 of the steel plate lid 3 projects into the plastic material of the peripheral flange, for example by being embedded or inserted in a groove in the plastic flange. More specifically, not only the folded part 27 but the whole of the transition part 28 and a part of the outward-facing flange 26 are within the plastic material. By this means, a good anchor is created in the securing part of the steel plate lid. The flange 29 is the thickest part of the collar 19 that changes at the bottom into a part 30 that has a relatively even thickness, and that has an extent in the vertical direction that is essentially the same as the extent of the flange 13 of the receptacle and has, at the bottom, a peripheral channel 31 that is shown most clearly in Figures 3 & 4. The channel 31 changes at the bottom into a circular bead 32 with a support surface 33, that is inclined downward and radially inward, and a rounded top 34. A peripheral engaging part 35 extends from the bead 32 in a slight arc and extends outward in the direction away from the wall of the receptacle down to its peripheral edge 36. On the outside of the collar 19, on

a level with the lower part of the bead 32, there is a circular groove 37 that forms a fold-line or hinge for the engaging part, that is intended to be folded up toward the outside of the upper part of the collar 19 into an opening position in order to make it possible to lift off the lid.

In the lid's closing and securing position, that is shown most clearly in Figure 2, the bead 32 acts as a securing and locking device for the lid in conjunction with the flange 13 that is directed radially outward on the outside of the upper edge 6 of the receptacle by the bead projecting under the flange 13, more specifically under its rounded lower outer edge 17, and, as a result of the dimensioning of the collar and the flexibility of the plastic material, is pre- stressed in a direction radially inward in the securing position. As a result of the inclined support surface 33 of the bead, an axial downward force is also generated that urges the seal 24 of the lid against the crown 9 at the edge 1 of the receptacle. The result is thereby a tight and secure fastening of the lid to the receptacle.

In order to open the container, one hand is placed under the engaging part 35 and bends it upward and outward, whereupon the bead is bent downwards and is thereby pressed away from the fastening position so that the lid can be lifted off. The collar can be constructed in such a way that it is not possible to fold the engaging part upward straight away. Instead, the engaging part is provided with a seal in the form of, for example, a break indication, that gives access to the engaging part when it is broken so that the engaging part can thereafter be folded upward. This prevents unauthorized opening and resealing of the container.

As shown in Figures 3 and 4, the bead 32 is provided with at least one or preferably several passages or ducts 38 in the form of recesses that pass right through and that extend between the area above the bead and the area below the bead, that is the surroundings. The passage or passages are designed to remain open for the release of air and the removal of air from the area above the bead and, in a stage during the application of the lid, also from the inside of the container, as will be described in greater detail below. The section in Figure 3 shows a whole recess 38, while Figure 4 shows a section through a recess.

The application of the lid 3 on the receptacle 2 is carried out by means of a machine, through which receptacles are fed on a conveyor, while the lid is fed forward at a height exceeding the height of the receptacle. The machine can be of a previously-known type and will not be described in greater detail, while the method will be described with reference primarily to Figures 5-9. Figure 5 shows schematically a receptacle 2 and a lid in an initial position for applying the lid, after the receptacle has been provided with its content, for example a liquid product such as paint, in a previous step in a filling machine. The receptacle 2 stands upright with its opening 39 facing upward toward the lid that is positioned directly above, that is with the axes of rotation 1 of the lid and of the receptacle coinciding. From this position, the lid 3 is lowered by means of a known mechanism (not shown), for example with suction cups under a vacuum, until the lid makes contact with the upper edge 6 of the receptacle. More specifically, the lid will come to rest first with the peripheral bead 32 on the flange 13 of the edge 6 of the receptacle, see Figure 6. With the lid in this position, a downward-pressing device is brought down in the form of a pressure plate 40 that is driven by a power device that moves linearly forward and backward (not shown, for example a pneumatic or hydraulic piston cylinder driven by a compressed medium). The pressure plate is pressed against the top side of the edge 8 of the lid, that is its upward-facing surfaces, that can be both the top side 22 of the flange 20 and the top side 41 of the plastic collar 19, which in the example are at the same height, around at least most of the circumference of the lid. As shown by the sections according to Figures 1 and 5-9, in this example the collar 19 has, for example, two depressions at the top, primarily for reasons associated with manufacturing technology.

As shown by, for example, Figure 8, the underside of bead 32 also has an inclined surface 42 that slopes upward and inward and the flange 13 on the receptacle has a rounded upper edge 43. With a continued pressing movement downward of the pressure plate 40, the bead will slide around the surface of the flange while springing out the collar 19 until the bead is below the flange and snaps into its locking position under the lower edge 44 of the flange, as shown in Figure 9 and in larger scale in Figure 2. Throughout the whole of this movement, the volume of air enclosed by the lid and the

receptacle is reduced, so that the air is forced out. This is made possible, according to the invention, by the passage 38 or passages in the bead, that can let air pass through during the whole time that the lid is being pressed down and even when it is in the locked position. In the locked position, however, the seal 24 of the lid has reached the sealing position in contact with the crown 9 of the upper edge of the receptacle with such a pre- stressing that the seal is compressed slightly, in order to ensure that there is a good seal. As a result of the top side 41 of the collar 19 being on a level with or possibly slightly above the top side 22 of the flange 13, the pressure device makes contact directly against the collar and as the collar is located at some distance from the receptacle in a radial direction, forces arise that provide the locking function. By this means, the receptacle has been sealed and the content has been prevented from leaking out and from being broken down by the outer air. A certain amount of air always remains above the surface 45 of the product, as a container can never be filled completely full for technical reasons.

The invention is not limited to the example that is described above and shown in the drawings. The number of passages can vary, up to a very large number by, for example, providing the bead with transverse fluting. The attachment of the collar 19 to the attachment part 27, 28 of the steel plate lid 3 can be designed in various ways. For example, the edge of the plate can project straight outward or can be bent in a way different to that shown, for example it can be bent downward. Alternatively, the receptacle can be made of a plastic material, and it is also possible for the lid to be manufactured completely of a plastic material, that is with both the collar 19 and the closing part 46 being made of plastic in one piece. By this means, an attachment part is not required, and the lid is an integrated unit. It is also possible for the container not to be symmetrical around its axis of rotation, but to be box- shaped with, however, well-rounded corners.