JP4907047B2 - Method for attaching opening device to packaging material and package obtained by the method - Google Patents

Abstract

A method for applying an opening device (3, 3', 3'') to a sheet packaging material for packaging pourable food products, comprising the step of fitting a frame (10, 30) of the opening device (3, 3', 3'') to the packaging material in a position, in which it extends across a crease line (14, 14', 35) designed to define an edge (15, 15', 36) of the finished package (1, 1', 1'').

Description

[0001]
(Technical field)
The present invention relates to a method of attaching an opening device to a packaging material for packaging liquid food, and a package obtained by the method.
[0002]
(Conventional technology)
Many liquid foods, such as fruit juice, UHT (ultra high temperature processed) milk, wine, tomato sauce, etc., are sold in packages made of sterile packaging materials.
[0003]
A typical example of such a package is a parallelepiped shaped package for liquid food or liquid food known as Tetra Brick® or Tetra Brick Aseptic®, which are laminated. It is formed by bending and sealing a web-shaped packaging material. This packaging material has a multilayer structure, and includes a layer of a fiber material such as paper, and both sides thereof are covered with a layer of a heat-sealable plastic material such as polyethylene. In the case of a sterile package for long-term storage, such as UHT (ultra high temperature processing) milk, the packaging material also includes an oxygen barrier material layer formed, for example, of aluminum foil, which is overlaid on a heat-sealable plastic material layer. And is further covered with another heat-sealable plastic material layer that will ultimately form the inner surface of the package that contacts the food.
[0004]
As is well known, such a package is formed by a fully automatic packaging unit, in which a continuous tube is formed from the packaging material fed as a web, the packaging material web being, for example, a hydrogen peroxide solution in the packaging unit itself. The sterilizing agent is removed from the surface of the packaging material by, for example, heating and evaporating after the sterilizing treatment, and the sterilized packaging material web is closed. Held in a sterile environment and folded to form a vertical tube and sealed longitudinally.
[0005]
The tube is continuously filled with aseptic or sterilized food from the top, sealed, and cut into equally spaced lateral sections to form pillow-shaped packs that are then machined. And is formed into a package having a finished shape, for example, a substantially parallelepiped shape.
[0006]
Alternatively, the packaging material can be cut into raw materials, which can be formed into packages on the forming spindle, and the formed packages are filled with wells and sealed. An example of such a package is the so-called “mountain crest” package generally known under the name Tetra Rex®.
[0007]
Such packages generally include an opening device that can be closed again to consume the food in the package and to prevent external objects from entering the package and contacting the food.
[0008]
The currently most commonly used opening device forms a spout and is hinged or screwed to the frame to attach to the hole or piercing or tearing portion of the package wall to open the package Therefore, it is composed of a lid that can be removed (moved). Instead of this, the use of other e.g. sliding opening devices is also known.
[0009]
For example, according to WO 98/18608 and WO 98/18609, devices and methods for injection molding of plastic material opening devices for holes formed in packaging material sheets are already known.
[0010]
The opening device described above is often located on the top wall of the package. As is well known, the top wall of a package formed from packaging material tubes has a number of sealing strips that limit the space available for forming the opening device. In particular, the top wall is folded over the surface to form a flat transverse sealing strip that forms the same plane, and a flat longitudinal sealing strip extending perpendicularly from the transverse sealing strip. The end intersects along the center line. More particularly, the longitudinal sealing strip extends along a portion of the top wall of the package and extends downward from the top wall along one side wall and bottom wall of the package.
[0011]
Similarly, the package formed by the spindle also has a top wall that intersects along a centerline with a flat lateral sealing strip that is folded onto the surface of the top wall to form the same plane.
[0012]
In either case, the opening device cannot be attached to the sealing strip of the package, causing not only the problem of tightly sealing the opening device on an irregular surface, but also compromising the integrity of the seal itself. Become.
[0013]
Thus, the opening device can only be attached to a limited size flat portion adjacent to the sealing strip extending across the top wall of the package, which clearly limits the maximum dimensions of the opening device. It will be.
[0014]
The larger the spout, the better the pour. Therefore, there is a need for a large opening device that provides a good pour condition, particularly in view of the increasing number of different products that are sold in packages, especially packed in paper-like packaging materials. Some such products, especially semi-liquid products or products containing fibers or granules, require large opening devices to be able to be poured smoothly.
[0015]
In addition, the opening device is usually placed at a distance from the fold line that forms the edge of the top wall to avoid the perimeter of the plastic frame from interfering with the package. The greater the distance between the opening device and the lateral edge of the top wall on the pouring side of the package, the greater the risk that the liquid product will spill along the adjacent side walls of the package during pouring.
[0016]
(Disclosure of the Invention)
It is an object of the present invention to provide a method for attaching an opening device to a sheet-like packaging material for packaging liquid foods, the method being designed to easily solve the above-mentioned drawbacks typically caused by known methods. Is to provide.
[0017]
According to the present invention, a sheet-like package for packaging a fluid food that includes a plurality of fold lines and the packaging material itself is folded along the fold lines to form a package filled with the fluid food. A method of attaching an opening device comprising a frame forming a spout and a movable lid closing the spout to a material, straddling one of the fold lines forming one edge of the package And attaching the frame to the packaging material with the frame extended.
[0018]
The present invention also provides an opening device that is formed of a sheet-like packaging material having a plurality of fold lines, and is configured by a frame that is attached to the packaging material to form a spout and a movable lid that closes the spout The sealed package for fluid foods provided, wherein the frame extends across one of the fold lines forming one edge of the package.
[0019]
Numerous preferred non-limiting embodiments of the present invention will now be described by way of example with reference to the accompanying drawings.
[0020]
(Best Mode for Carrying Out the Invention)
Reference numeral 1 in FIG. 1 denotes a hermetic package for liquid food, for example, a parallelepiped shaped package known as Tetra Brix Aseptic®, which is a packaging material as described in detail above. A package made from a web 2 (partially shown in FIGS. 5 and 6) in the shape of a parallelepiped for liquid food or liquid food, formed of a plastic material and on top of the package 1 A recloseable opening device 3 is provided which is preferably attached.
[0021]
The package 1 has a top wall 4, a bottom wall (not shown) facing the top wall 4, a front wall 5, a rear wall (not shown), and a pair of side walls 6 (only one is shown in FIG. 1). As shown).
[0022]
The packaging material web 2 and the package 1 have a multilayer structure (not shown) and include a layer of fibrous material, usually paper, both sides of which are covered with a layer of thermoplastic material, for example polyethylene. Configured. The side of the packaging material that ultimately contacts the food in the package 1 also has a layer of oxygen barrier material, such as aluminum, which is covered with one or more layers of thermoplastic.
[0023]
The web 2 includes a plurality of weakening lines obtained by forming a fold line that folds the material in the forming and final stages by means of a folding pattern 7, i.e. a crease-forming roll.
[0024]
The package 1 is preferably formed from a continuous tube of packaging material (not shown), which is obtained by folding the tube 2 along the side edges and sealing the web 2 in the longitudinal direction. Exactly, a longitudinal seal 8 is formed by sealing the edge of the web 2 over the opposite edge, which seal 8 is perpendicular to the rear wall (not shown) of the finished package 1. It has a central portion that extends along the centerline and opposite ends that extend along the bottom and top walls 4 of the package.
[0025]
Thereafter, the tube is laterally sealed at regular intervals to form a lateral seal 9 that extends along the bottom and top walls 4 of the package 1. The tube is then cut along the transverse seal 9 to form a so-called pillow pack, which is an intermediate product that is made into a finished package 1 by a plurality of final folding steps.
[0026]
Referring to FIGS. 1, 6, 7, and 8, the opening device 3 forms a circular spout 11 for pouring out food contained in the package 1, and the hole 12 of the package 1. (FIG. 5, FIG. 7, FIG. 8), an annular frame 10 formed with external threads attached to the top of the package 1 and a frame 10 formed separately from the frame 10 and closed at a position where the spout 11 is closed. It is comprised with the lid | cover or cap 13 screwed together. Once opened, the cap 13 can be moved between the closed position and the open position removed from the frame 10.
[0027]
In particular, holes 7 are stamped in the web 2 and the opening device 3 is attached to the packaging material before the web 2 enters the section of the filling machine (not shown) for forming, filling and sealing. Is folded and longitudinally sealed to form the above-described vertical tube filled with fluid food.
[0028]
According to the invention, the hole 12 and the frame 10 of the opening device 3 extend across a fold line 14 that forms one edge of the package 1, which fold line 14 extends from the top wall 4 of the package 1. And a horizontal edge separating the front wall 5.
[0029]
The frame 10 of the opening device 3 is formed by injecting a plastic material through two holes 12 between two cooperating molding members (not shown) on opposite sides of the web 2. It is preferable that the opening device 3 is prevented from being detached from the hole 12 by burying the edge thereof.
[0030]
In particular, the thermoplastic coating of the web 2 melts during injection molding and merges with the plastic material of the frame 10 at the location of the holes 12.
[0031]
Alternatively, the frame 10 of the opening device 3 can be attached to the packaging material of the web 2 by adhesion or by welding with a heating member or an ultrasonic sealing member.
[0032]
1-4, 7 and 8, the frame 10 has a flat annular flange 16 attached to the top wall 4 and the front wall 5 and a spout 11 protruding from the inner edge of the flange 16. It is comprised with the cyclic | annular part 20 in which the external thread was formed cylindrical.
[0033]
The flange 16 is composed of a circular main portion 21 and a rectangular lateral flap 22 protruding from the side surface of the main portion 21 in the same plane. The spout 11 of the annular portion 20 is preferably covered with a tear seal.
[0034]
During the molding operation of the package 1, the flange 16 is bent at the fold line 14, while the main portion 21 extends along the top wall 4 between the fold line 14 and the associated lateral seal 9, The flap 22 extends along the front wall 5.
[0035]
In order to facilitate the folding of the fold line 14, the flange 16 is provided with a notch, three different embodiments of which are shown in FIGS. 2, 3 and 4, designated 24a, 24b and 24c respectively. It is attached. Each notch 24 a, 24 b, 24 c extends between the flap 22 and the main portion 21 and is designed to be located on the fold line 14.
[0036]
The notch 24 a has a straight shape parallel to the fold line 14, the notch 24 b has an hourglass shape, and the notch 24 c has a shape similar to an hourglass, but a thin central portion of the annular portion 20 of the frame 10. It has a phase shape on the outer contour.
[0037]
The straight notch 24a of FIG. 2 gives the possibility of increasing the diameter of the spout 11 compared to the notches 24b, 24c, but the frame 10 must be accurately positioned so that the notch 24a is located on the fold line 14. Don't be.
[0038]
The position of the hourglass-shaped notch 24b relative to the fold line 14 is not critical. Indeed, as long as the fold line 14 is positioned within the outer limits of the notch 24b, the frame 10 is bent at the position of the notch. Depending on the position of the fold line 14 relative to the notch 24b, the package 1 bulges slightly inward or outward of the frame 10. This bulge is hardly noticeable by casual observation.
[0039]
The notch 24c has a shape similar to an hourglass. The intent is that the fold line 14 should be aligned with the widened end of the notch 24c, which is slightly different from the edge 15 of the package 1 as the frame 10 is shown in FIG. Means protruding. In this case, the spout 11 can have a larger diameter because it can be arranged so as to be closer to or protrude from the fold line 14. Therefore, the risk of food spilling on the front wall 5 of the package 1 during pouring is small.
[0040]
As shown in FIG. 5, the hole 12 has the same contour as the flange 16 of the frame 10. The outer diameter of the hole 12 is slightly smaller than the outer diameter of the flange 16 of the frame 10. Therefore, when the flange 16 of the frame 10 is positioned on the hole 12, the peripheral edge of the flange 16 overlaps with the hole 12. The hole 12 is primarily located in the portion of the web 2 designed to form the top wall 4 of the package 1 and has an end formed in the portion of the web 2 designed to form the front wall 5. As described above, the hole 12 intersects the fold line 14 located between the top wall 4 and the front wall 5.
[0041]
Referring to FIGS. 1 and 6 to 8, the cap 13 protrudes from a circular portion 25 for closing the spout 11 and a circular outer peripheral edge of the circular portion 25, and is screwed onto the annular portion 20 of the frame 10. It is constituted integrally with an annular portion 26 formed with a cylindrical inner screw.
[0042]
9, 10 and 11 show the basic principle of the present invention applied to the packages 1 ′, 1 ″, and these packages are described only as being different from the package 1 and have already been described. Similar or identical parts are denoted by the same reference numerals.
[0043]
Referring to FIG. 9, the package 1 'has a curved front wall 5', and thus a curved fold line 14 ', and thus a curved edge 15' separating the front wall itself from the top wall 4 '. It differs from the package 1 in having it. The package 1 ′ comprises an opening device 3 ′ which is completely similar to the opening device 3, and these parts are labeled with the same reference numerals as the corresponding parts of the opening device 3. The frame 10 of the opening device 3 ′ has a notch (not shown) that can have the same shape as the notches 24a, 24b, and 24c, and is arranged at the position of the curved folding line 14 ′, and has the same curved shape. Is given. The curved folding line 14 'and the curved shape of the notch of the frame 10 of the opening device 3' are both convex. All other parts of the package 1 ′ and the opening device 3 ′ in the embodiment of FIG. Accordingly, the frame 10 of the opening device 3 ′ extends across the fold line 14 ′, and a main portion 21 ′ disposed on the top wall 4 ′ and a flap 22 ′ disposed on the front wall 5 ′. A flat annular flange 16 ', preferably comprising
[0044]
Referring to FIGS. 10 and 11, the package 1 ″ is different from the package 1 in that the package 1 ″ includes an opening device 3 ″ of “hinging type”.
[0045]
The package 1 '' has a parallelepiped shape and is bounded by a plurality of walls having the same reference numerals as the corresponding walls of the package 1.
[0046]
The opening device 3 ″ is connected to the frame 30 by a frame 30 that forms a spout 31 and is attached to the top of the package 1 ″ at the location of the hole 32 and a hinge 34 that defines an axis A parallel to the top wall 4. And a lid 33.
[0047]
The hole 32 and the frame 30 of the opening device 3 ″ extend across a fold line 35 defining one edge of the package 1 ″ parallel to the axis A. In the embodiment shown in FIGS. 10 and 11, the fold line 35 defines a horizontal edge 36 of the package 1 ″ that separates the top wall 4 from the adjacent side wall 6.
[0048]
The lid 33 is molded integrally with the frame 30.
[0049]
Again, the opening device 3 '' is applied to the packaging material web at the location of the hole 32 before entering the section where the web forms, fills and seals the filling machine (not shown) forming the final package 1. Preferably it is attached.
[0050]
In particular, the opening device 3 '' is formed by injecting a plastic material through two holes 32 between two cooperating molding members (not shown) on opposite sides of the packaging material web, the frame 30 being The perimeter of the hole 32 is preferably buried so as to prevent the opening device 3 ″ from detaching from the hole 32. More particularly, the frame 30 forms a substantially flat annular base flange 37 which is locked onto a first surface 39 of packaging material adapted to form the inner surface of the package 1 ''. A plurality of coplanar fins 38 extend in a plane parallel to the base flange 37 and are locked onto the second surface 40 of the packaging material opposite the first surface 39.
[0051]
Alternatively, the frame 30 of the opening device 3 '' can be attached to the packaging material by means of an adhesive or by welding with a heating member or an ultrasonic sealing member.
[0052]
The frame 30, the spout 31 and the lid 33 have respective elongated shapes in the direction of the lateral seal 9 on the top wall 4.
[0053]
The frame 30 further includes a raised annular neck 41 extending from the base flange 37 and bounding the spout 31.
[0054]
The base flange 37 of the frame 30 is folded on a fold line 35 so that a substantially square main portion 42 of the base flange 37 extends along the top wall 4 and tapers opposite the base flange hinge 34. The end portion 43 extends along the side wall 6. The tapered end 43 is substantially V-shaped and has a rounded apex.
[0055]
In order to facilitate the folding of the frame 30 on the fold line 35, the base flange 37 has notches (not visible), which are notches 24a, 24b, 24c of the opening device 3. And can extend along the bottom surface of the base flange itself.
[0056]
The neck 41 forms a flat top flange 45 that is substantially square and projects relative to the neck itself.
[0057]
The lid 33 has a flat main portion 46 connected to the frame 30 by a hinge 34 and a raised substantially protruding from the main portion 46 extending from the end of the hinge 34 and engaging the neck 41. It is composed of a U-shaped sealing lip 47. The lid 33 is initially sealed against the inner edge 44 of the top flange 45 of the frame 30 that surrounds the spout 31 by a thin breakable rib 48 that extends along a peripheral line around the sealing lip 47. The rib 48 is broken when the lid 33 is opened.
[0058]
Conveniently, the inner edge 44 of the top flange 45 of the frame 30 and the lip 47 of the lid 33 are weighed to form a pointed spout 50.
[0059]
At the spout 50, the top flange 45 forms a pour 51 that protrudes from the neck 41 on the fold line 35.
[0060]
Once opened, the lid 33 moves between an open position (FIG. 10) and a closed position (FIG. 11), where the rib 48 snaps over the inner edge 44 and snaps into engagement. The lip 47 of the lid 33 is held fluid tight inside the neck 41 of the frame 30.
[0061]
The lid 33 forms a pull tab 52 at the end opposite to the hinge 34, and the pull tab 52 protrudes outward with respect to the spout 31 on the folding line 35 side and faces the hinge 34 of the frame 30. The pull tab 52 forms a handle portion of the lid 33 that is pulled upward by the user to lift the lid 33 into the open position. The pull tab 52 is bent toward the side wall 6, and its distal end is integrally connected to the end 43 of the base flange 37 by a breakable strip 53 forming an anti-tamper piece. When the pull tab 52 of the lid 33 is pulled upward, the strip 53 is broken so that the package 1 '' can be opened.
[0062]
The advantages of the method and package 1, 1 ′, 1 ″ according to the invention will become apparent in the following description.
[0063]
In particular, the frame 10, 30 of the opening device 3, 3 ′, 3 ″ extends across the fold lines 14, 14 ′, 35 or the edges 15, 15 ′ of the package 1, 1 ′, 1 ″. 3, 3 ′, 3 ″ spouts 11, 31 are located immediately adjacent to the above-mentioned edges 15, 15 ′, 36, thereby improving the pouring of food and lowering the spout The risk of spilling food on the walls (5, 5 ', 6) is minimized.
[0064]
Since the opening device 3, 3 ', 3 "can straddle the edges 15, 15', 36 of the package 1, 1 ', 1", on the top wall 4, 4' to receive the opening device Larger space can be used. This means that the opening device is enlarged and the spout is enlarged resulting in improved pouring.
[0065]
The arrangement of the opening devices 3, 3 ′, 3 ″ across the edges 15, 15 ′, 36 of the packages 1, 1 ′, 1 ″ reinforces the edges that are most susceptible to damage during transportation and handling.
[0066]
Also, the arrangement of the opening devices 3, 3 ′, 3 ″ across the edges 15, 15 ′, 36 of the packages 1, 1 ′, 1 ″ increases the pleasure of drinking directly. This is because good "lip adhesion", ie the drinker's lips do not touch the packaging material, but only the plastic. In some countries, users are known to accept this improvement.
[0067]
The packages 1, 1 ′, 1 ″ are less likely to misposition the opening devices 3, 3 ′, 3 ″ with respect to the edges 15, 15 ′, 36. This is because the folding of the packaging material along the folding lines 14, 14 ', 15 defining the edges themselves is made by folding the plastic frames 10, 30 of the opening devices 3, 3', 3 ". It is.
[0068]
Finally, in the case of the package 1 '', the peripheral edge of the tapered end 43 of the base flange 37 is locked on the vertical side wall 6, thereby causing a load caused by transportation or handling acting on the protruding pull tab 52. Increase the resistance of the spout 50 to external loads.
[0069]
As will be apparent, changes may be made in the methods and packages 1, 1 ′, 1 ″ described and illustrated herein without departing from the scope described in the claims.
[Brief description of the drawings]
FIG. 1 is a top perspective view of a hermetic package for liquid food according to the present invention.
2 is a bottom view of an alternative embodiment of the frame of the opening device in the package of FIG. 1. FIG.
3 is a bottom view of an alternative embodiment of the frame of the opening device in the package of FIG. 1. FIG.
4 is a bottom view of an alternative embodiment of the frame of the opening device in the package of FIG. 1. FIG.
5 is a top view of a packaging material web that is provided with one of the frames of the opening device of FIGS. 2, 3 and 4 to form the package of FIG. 1. FIG.
6 is a top view of a portion of the packaging material web of FIG. 5 with the frame of the opening device of FIG. 3;
7 is a cross-sectional view of the packaging material web taken along line VII-VII in FIG. 6;
8 is a cross-sectional view of FIG. 7 after the packaging material web has been folded to form the package of FIG.
FIG. 9 is a top perspective view of a sealed package for liquid food according to another embodiment of the present invention.
FIG. 10 is a top perspective view of a sealed package for liquid food according to another embodiment of the present invention.
11 is an enlarged cross-sectional view of the upper portion of the package of FIG.

Claims (16)

For packaging of liquid food, including a plurality of fold lines, and the packaging material itself is folded along the fold lines to form a package (1, 1 ′, 1 ″) filled with the liquid food An opening device (3, 33) having a frame (10, 30) forming a spout (11, 31) and a movable lid (13, 33) for closing the spout (11, 31) for a sheet-like packaging material. 3 ′, 3 ″), the fold line (14, 14 ′ ) forming one edge (15, 15 ′, 36) of the package (1, 1 ′, 1 ″). , 35) is attached to the packaging material so that the frame (10, 30) extends over one of the frames (10, 30), and the frame (10, 30) is bent. Hole (12, 14) of said packaging material straddling said one of the lines (14, 14 ', 35) Wherein the attachment to 2). The method according to claim 1, characterized in that said opening device (3, 3 ', 3'') which is at least the frame (10, 30) is injection molded directly to the packaging material. The method of claim 1, wherein the opening device (3, 3 ', 3'') is the frame (10, 30) of, characterized in that attached to the packaging material with an adhesive. The method according to claim 1 or 2 , characterized in that the frame (10, 30) of the opening device (3, 3 ', 3'') is welded to the packaging material. Before the packaging material (2) delivered as a web enters the forming, filling and sealing section of the filling machine for producing a hermetic package (1, 1 ', 1'') of fluid food, the method as claimed in any one of up to claims 1 to 4, wherein said opening device (3, 3 ', 3'') that is mounted against. When the opening device (3, 3 ′, 3 ″) is attached to the packaging material (2) supplied as the web , the frame (10, 30) is the fold line (14, 14 ′, 35). the formed a notch (2 4a, 2 4b, 2 4c) one to match the position of the notch (2 4a, 2 4b when the package (1, 1 ', 1'') is formed a method as claimed in claim 5, wherein the frame along a 2 4c) (10,30) is characterized in that it is bent. The frame (10, 30) and the spout (11, 31) which are formed from a sheet-like packaging material having a plurality of fold lines and are attached to the packaging material to form the spout (11, 31) are closed. configured opening device by a movable cover (13, 33) (3, 3 ', 3'') flow seal package for dynamic food (1, 1', 1 '') with a a, said package The frame (10, 30) straddling one of the fold lines (14, 14 ', 35) forming one edge (15, 15', 36) of (1, 1 ', 1'') The frame (10, 30) is attached to a hole (12, 32) straddling the one of the fold lines (14, 14 ′, 35). . The one of the fold lines (14, 14 ', 35) is a first and second wall (4, 5; 4', 5 '; 4,) of the package (1, 1', 1 ''). 6) and a first portion (21, 21 ′, 42) and a second wall (5, 5) extending along said first wall (4, 4 ′). Package according to claim 7, characterized in that the frame (10, 30) has a second part (22, 22 ', 43) extending along 5', 6). Said frame (10, 30) has a notch (2 4a, 2 4b, 2 4c) at a position coincident with said one of said fold lines (14, 14 ', 35), said notch (2 4a, 2 4b, 2 4c) package according to claim 7 or claim 8 wherein the frame (10, 30) is characterized in that it is folded along. Wherein a notch (24a) is straight, the package of claim 9, wherein the fold lines (14, 14 ', 35), characterized in that parallel to said one of. 10. Package according to claim 9 , characterized in that the notch (24b) has the shape of an hourglass. The notch (24c) has a shape similar to an hourglass, and a thin central portion is along the periphery of the spout (11, 31) of the opening device (3, 3 ′, 3 ″). The package according to claim 9 . Package according to any one of claims 7 to 12 , characterized in that the one of the fold lines is a curved fold line (14 '). 14. Package according to claim 13 , characterized in that the notches (24a, 24b, 24c) are arranged at the position of the curved fold line (14 ') and are given the same curved shape. 15. Package according to any one of claims 7 to 14 , characterized in that the frame (10) has an annular part (20) which is cylindrical and externally threaded. 15. Package according to any one of claims 7 to 14 , characterized in that the lid (33) is connected to the frame (30) by a hinge (34).

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