METHOD FOR INTRODUCING AN EXPANDABLE TOOL INTO A CONTAINER

Abstract

 The present invention relates to a method and a device for introducing an expandable tool (20) into a container (30). The container (30) has a container body (31) and a container neck (32). The expandable tool (20) has a body (21) and a neck (22). The method comprises the steps of:
- providing the expandable tool (20) in an everted form
- holding the neck (22),
- providing the container (30) such that the container neck (32) and the neck (22) are arranged opposite one another.
To introduce the expandable tool (20) into the container (30), the expandable tool (20) is blown into the container (30) through the neck (22).

Description

[0001] The present invention relates to a method and a device for introducing an expandable tool into a container, in particular into a fiber-based container, and to a method for reducing the water content in a wet fiber-based container in accordance with the preamble of the independent claims.

[0002] A fiber-based blank in the form of a container was disclosed in WO 2012/139590 A1. To produce this container, so-called pulp is injected into an upside-down mold and pressed against a corresponding wall in this mold using a flexible balloon and compressed accordingly. The pulp is compressed and heated to a temperature of around 180°C in order to dry the container.

[0003] The pulp is a mixture of fibers and water, in particular natural fibers such as hemp fibers, cellulose fibers or flax fibers or a mixture thereof. Optionally, the pulp has additives that, for example, improve the curing of the compressed pulp or have an influence on the later appearance or generally change the properties of the pulp or the later container.

[0004] The flexible balloon of WO 2012/139590 A1 can substantially correspond to the shape of the container to be manufactured. However, this has the disadvantage that the flexible balloon can have diameters that are larger than openings of the container. The insertion and removal of the flexible balloon can thus damage the container by contact. To avoid this, it is provided to twist the flexible balloon. For this purpose, a device is arranged in the flexible balloon and connected thereto.

[0005] The repeated twisting of the flexible balloon results in increased wear and thus faster fatigue of the flexible balloon. In other words, its service life is shortened. In addition, rotation as shown in WO 2012/139590 A1 requires an additional element that is connected to the flexible balloon. On the one hand, this makes the device complicated and complex, and on the other hand, excessive wear is associated with an increased maintenance costs. The consistent twisting causes the balloon to fold in the same places every time. On the one hand, these are weak points, and on the other hand, these are possibly places that may leave marks on the container to be pressed.

[0006] It is the object of the invention to remedy at least one of the disadvantages of the prior art. In particular, a method for introducing an expandable tool into a container and preferably a corresponding device is to be provided, which is simple, counteracts excessive wear of the expandable tool and, in particular, avoids damage to the container.

[0007] This object is achieved by the methods and devices defined in the independent claims. Further embodiments emerge from the dependent claims.

[0008] A method in accordance with the invention relates to a method for introducing an expandable tool into a container. The container has a container body and a container neck and is in particular a fiber-based container. The expandable tool similarly has a body and a neck. The method comprises at least the following steps:

• providing the expandable tool in an everted form
• holding the neck,
• providing the container such that the container neck and the neck of the expandable tool are arranged opposite one another.

[0009] To introduce the expandable tool into the container, the expandable tool is blown into the container through the neck of the expandable tool such that the expandable tool is turned back, or inverted, into its original configuration.

[0010] In the present case, everted means that the interior of the expandable tool is turned or has been turned outward.

[0011] By introducing the expandable tool by means of injection, a complicated device for moving the expandable tool can be dispensed with. The expandable tool is accordingly no longer deformed by a fixed mechanism, but is deformed at the points of natural folding, i.e., where there is the least resistance. As a result of blowing, a turnover edge is typically formed on the expandable tool so that it is rolled into the container. This results in a very gentle introduction of the expandable tool into the container.

[0012] Preferably, the expandable tool is provided in the everted form within a pressure chamber. On the one hand, a specific environment can be created for the expandable tool, i.e., an environment that is, for example, isolated from the surroundings, and on the other hand the pressure chamber can also have corresponding preferred dimensions. For example, the pressure chamber can be designed such that its inner diameter or generally its inner dimension transverse to a longitudinal axis is smaller than the corresponding dimension of the expandable tool in its everted form. As a result, it is possible, for example, for the expandable tool to rest on an inner wall of the pressure chamber in its everted form.

[0013] Accordingly, friction arises between the expandable tool and the inner wall of the pressure chamber.

[0014] The effect is explained by way of example below. In a simple configuration, the pressure chamber is substantially tubular and the expandable tool is likewise substantially cylindrical. Accordingly, the pressure chamber and the expandable tool have a substantially circular cross section transverse to the respective longitudinal axis. The pressure chamber is preferably longer in an axial direction than the everted expandable tool. If the everted expandable tool is now blown into the container to be manufactured from the side of a base, i.e., a side opposite the neck, the base of the expandable tool moves into the expandable tool and rolls along the inner wall of the pressure chamber inside the expandable tool. The base of the expandable tool is subsequently moved into the container through the neck of the expandable tool.

[0015] A longitudinal axis or the longitudinal axis is typically defined by the connection of a base of the container to a dispensing opening of the container. This also applies analogously to the expandable tool. In the present case, the longitudinal axis coincides with the machining direction.

[0016] Alternatively, if less friction is present, the expandable tool might collapse upon the application of pressure. In this configuration, the sidewalls of the body of the expandable tool are folded in the area of then neck of the expandable tool and the body of the expandable tool is rolled into the container to be manufactured along the inner wall of the container.

[0017] The pressure chamber is pressurized by a fluid, in particular compressed air, in order to blow the expandable tool into the container.

[0018] As a result, very specific process conditions can be created and the speed of the movement, such as rolling, of the expandable tool can be easily adapted. In addition, such a configuration allows very good control of the process conditions in terms of cleanliness and allows them to be repeated over and over again under the same conditions.

[0019] To evert the expandable tool, provision can be made to apply a vacuum to the interior of the expandable tool.

[0020] The advantages arise analogously to the process when the expandable tool is inverted or turned back. In the present case, everting means moving the interior of the expandable tool outward through the neck of the expandable tool. When a vacuum is applied to the expandable tool, it begins to collapse. As soon as the first resistance occurs, for example in the region of the container neck due to friction, a base of the expandable tool will begin to move into the interior of the expandable tool, i.e., collapse. This process then causes the side walls of the expandable container to begin to fold over, providing a turnover edge, so that they are also rolled into the interior of the expandable tool. When a vacuum continues to be applied to the expandable tool, the base or the side walls will roll further into the interior of the expandable tool and then move outward through the neck of the expandable tool, leaving it in the everted form.

[0021] To apply a vacuum to the expandable tool, a vacuum can be applied to the pressure chamber.

[0022] This results in a substantially closed system that is typically independent of environmental conditions. Within this system, certain specific process conditions can be created and, for example, a desired purity can also be maintained.

[0023] It can be provided that a dry lubricant is applied to the interior of the expandable tool before the first use or at certain intervals in order to prevent excessive adhesion of the expandable tool to other elements, in particular within the pressure chamber.

[0024] The dry lubricant may be starch or flour, preferably talc.

[0025] The expandable tool can have a geometrically similar contour to the inner contour of the finished container with a scaling factor of greater than 50%, preferably greater than 80%, in particular greater than 90% and preferably between 94% and 98%. The expandable tool can in particular have a congruent contour with respect to the container.

[0026] A correspondingly similar or congruent contour ensures that the expandable tool always expands uniformly and that the loads on the expandable tool are correspondingly uniformly applied. For example, in the case of a bottle having different diameters in the region of the body, a substantially cylindrical expandable tool in this region would have to expand differently in order to map the contour of the bottle. However, if the contours are similar, the expandable tool has substantially the same elongation at each point of the container during a subsequent pressing operation.

[0027] It can be provided that an overpressure is applied to the expandable tool for blowing in the expandable tool, the overpressure being preferably at least 0.1 bar but not more than 2 bar.

[0028] During the process, the expandable tool is preferably held in the region of its neck. In this case, the expandable tool can have a thickened portion on its neck. For example, this thickened portion may be configured to protrude radially, in particular circumferentially around the neck. In this case, the expandable tool can be held easily and does not need to be stretched in the region of the thickened portion during insertion or removal. A turnover edge is correspondingly arranged radially inward of the thickened portion.

[0029] A further aspect relates to a method for reducing the water content in a fiber-based container. The method comprises the steps of:

• providing a wet fiber-based container in a mold,
• introducing an expandable tool into the wet fiber-based container, the expandable tool being provided in an everted form for introducing the expandable tool and being blown into the container through its own neck, in particular in accordance with a method as described herein,
• expanding the expandable tool.

[0030] By blowing in the expandable tool, it can be gently introduced into the wet fiber-based container without the need for additional tools. By expanding the expandable tool introduced in this way, liquid can be pressed out of the wet fiber-based container and the moisture, i.e., the water content, of the fiber-based container can be significantly reduced.

[0031] In the present method, the wet fiber-based blanks are typically shaped as already known in the prior art. In other words, pulp is introduced into a porous casting mold or into a solid casting mold having water-draining channels, the inlets of which are covered with screens or the openings of which are small enough that the fibers of the pulp cannot penetrate, and the fibers of the pulp are applied to the inner wall of the casting mold so as to form a wall of a container. Once the wall is sufficiently thick, the coating of the pulp stops. The semi-finished product now present, i.e., the wet fiber-based container, is removed from the casting mold and introduced into the mold and thus provided in the mold. At this point, the wet fiber-based container has a water content of approximately 75%.

[0032] The wet fiber-based container is removed from the casting mold using a suitable transfer device. Subsequently, the wet fiber-based container is inserted into the opened mold. The mold is preferably formed in two parts. In this case, removal and insertion may require blowing out and/or a suction by means of negative or positive pressure. It is also possible to use purely mechanical grippers for this transfer.

[0033] Typically, the mold can have an inner wall that is designed with a higher surface quality compared to the inner wall of the casting mold.

[0034] After the fiber-based container has been provided, the expandable tool is introduced into the fiber-based container as described in the present case. The water content of the fiber-based container can be reduced by expanding the expandable tool. At this point, the wet fiber-based container has a water content of approximately 50% to 60%.

[0035] A further aspect relates to a device for introducing an expandable tool into a container, in particular in accordance with a method as described herein. The device has a mold for receiving a wet fiber-based container. The device has a pressure chamber that is arranged opposite the mold.

[0036] As a result of such an arrangement, a vacuum or an overpressure can be produced in a simple manner in the region of an opening of the mold and can create specific process conditions for elements located in the pressure chamber.

[0037] In this case, it can be provided that an expandable tool having a neck is arranged within the pressure chamber. An opening on the mold for a container neck and the neck of the expandable tool are arranged opposite one another.

[0038] This makes it possible to move the expandable tool out of or into the mold by simply applying a vacuum or overpressure. The movement takes place substantially axially through the neck in the direction of the container neck or the corresponding region of the mold.

[0039] A holding device for holding the expandable tool is preferably arranged between the pressure chamber and the mold. The holding device can be designed in two parts, comprising a retainer ring and a corresponding counterpart, a pressing ring. The pressing ring can be designed as an integral component of the pressure chamber.

[0040] Preferably, the pressure chamber is connected to a device for producing an overpressure or a vacuum. This results in a substantially closed circuit that is substantially independent of environmental influences.

[0041] Preferably, the pressure chamber has an inner diameter that is smaller than an outer diameter of the expandable tool in its everted form. With regard to these diameter geometries, reference is explicitly made to the relationships already described in relation to the method for introducing the expandable tool into the container, and a repetition is dispensed with. The aforementioned advantages are fully applicable in the present case.

[0042] A corresponding method is described below with reference to figures. In the figures:

Fig. 1:

shows an expandable tool in its original configuration;

Fig. 2:

shows the expandable tool from Fig. 1 in an everted form, together with a mold;

Fig. 3:

shows the beginning of the blowing in of the expandable tool into the mold;

Fig. 4:

shows the completely blown-in expandable tool;

Fig. 5:

shows the completely blown-in expandable tool in its original configuration;

Fig. 6:

shows a holding device in an open representation;

Fig. 7:

shows the holding device from Fig. 6 with a clamped expandable tool.

[0043] Fig. 1 shows an expandable tool 20 in its original configuration. The expandable tool 20 has a base 24, a body 21 and a neck 22. A thickened portion 23 is arranged on the neck 22. The thickened portion 23 extends circumferentially around an opening on the neck 22. The thickened portion 23 is displaced radially outward in relation to the neck 22 so that said thickened portion provides a larger diameter in the present case than the neck 22. As can be seen in Fig. 1, the expandable tool 20 has a shape that substantially corresponds to the shape of a container to be formed. In other words, the contour of the expandable tool 20 is matched to the contour of the later container.

[0044] Fig. 2 shows the expandable tool 20 from Fig. 1 in an everted form, together with a mold 50. As can be seen, a container 30 is arranged within the mold 50 and is still wet in the present case and therefore has a moisture of more than 70%. In the present case, the container 30 is shown only schematically and fills the mold 50. In other words, the container 30 rests against the inner wall of the mold 50. The container itself has a container body 31 and a container neck 32. Between the container body 31 and the container neck 32 is a container shoulder (not specified in greater detail). In the region of the container shoulder, a diameter of the container neck 22 expands to a diameter of the container body 31. The expandable tool 20 is arranged so that the container neck 32 and the neck 22 oppose one another. The pressure chamber 40 in which the expandable tool 20 is located and the holding device 60 (see Fig. 6) are not shown in this illustration. The expandable tool 20, the pressure chamber 40, the holding device 60, the container 30 and the mold 50 are all aligned along a common longitudinal axis.

[0045] Fig. 3 shows the beginning of the blowing in of the expandable tool 20 into the mold 50, or into a container 30 arranged therein.

[0046] In order to introduce the expandable tool 20 into the container 30, compressed air is applied to the pressure chamber 40. When a minimum pressure is reached, the side walls of the body 21 of the expandable toll 20 adjoining the base 24 collapse. The so collapsed side walls begin to move in the direction of the interior of the container 30 or of the mold 50. Hence, the side walls begin to fold over, providing a turnover edge, in the area of the thickened portion 23 (see also Fig. 6) and roll along the interior of the container wall of the container 30 to be manufactured. The side walls thus slides over the interior of the expandable tool, which is already partially turned back through the neck 22 and the neck 32 into the container 30, as in the illustration in accordance with Fig. 3.

[0047] This process continues until a state shown in Fig. 4.

[0048] In an alternative embodiment, which is not shown in detail, the process of turning back the expandable tool, i.e. introducing the expandable tool into the container, is slightly different. If there is a high amount of friction between the expandable tool and the pressure chamber, upon application of the necessary pressure, the base 24 of the expandable tool 20 begins to move into the expandable tool 20. The side walls of the container body 21 adjoining the base 24 are folded over, providing a turnover edge, and roll along a tool wall in the direction of the interior of the container 30 or of the mold 50. As this process progresses, the base 24 of the expandable tool 20 moves through the neck 22 and the neck 32 moves into the container 30.

[0049] Fig. 4 now shows the expandable tool 20 completely blown into the container 30. During the further inflation, the expandable tool will assume its original configuration shown in Fig. 1.

[0050] This configuration is shown in Fig. 5. As can be seen in Fig. 5, the outer contour of the expandable tool 20 is substantially identical to the inner contour of the container 30, or is scaled to approximately 95%.

[0051] Subsequently, pressure can be applied to the expandable tool 20 in the configuration shown in Fig. 5 such that the still wet container 30 is pressed against the inner wall of the mold 50 and the excess water is drained from the container 30. For this purpose, channels are provided in the mold 50, which are not described in more detail here.

[0052] Fig. 6 shows a holding device 60 comprising a retaining ring 61 and a corresponding counterpart, a pressing ring 62. In the present case, the pressing ring 62 is designed as an integral component of the pressure chamber 40. The holding device 60 is provided to hold the expandable tool 20. For this purpose, a thickened portion 23 is formed on the expandable tool 20. In the present case, the thickened portion 23 is formed in the form of a circumferential bead that protrudes radially outwardly in relation to a longitudinal axis of the expandable tool 20. A correspondingly complementary recess is provided in the retaining ring 61. In order to hold the expandable tool 20, the thickened portion 23 is inserted into the corresponding recess on the retaining ring 61. Subsequently, the pressing ring 62, and in the present case the pressure chamber 40 together with the integral pressing ring 62, is placed on the thickened portion 23. The pressing ring 62 also has a recess for interacting with the thickened portion 23. When the pressing ring 62 is placed on the thickened portion 23 and the thickened portion 23 is thus placed on the retaining ring 61, the expandable tool 20 is securely held. A corresponding state is shown in Fig. 7.

[0053] This configuration makes it possible for the expandable tool 20, as shown in Fig. 7, to be able to be turned back upward or downward, hence, inverted and everted, easily and without interference in the embodiment shown in Fig. 7.

Claims

1. A method for introducing an expandable tool (20) into a container (30), in particular into a fiber-based container, the container (30) having a container body (31) and a container neck (32), and the expandable tool (20) having a body (21) and a neck (22), comprising the steps of:

- providing the expandable tool (20) in an everted form

- holding the neck (22),

- providing the container (30) such that the container neck (32) and the neck (22) are arranged opposite one another, characterized in that, to introduce the expandable tool (20) into the container (30), the expandable tool (20) is blown into the container (30) through the neck (22) such that the expandable tool (20) is turned back into its original configuration.

2. The method in accordance with claim 1, characterized in that the expandable tool (20) is provided in the everted form within a pressure chamber (40).

3. The method in accordance with claim 1 or 2, characterized in that the pressure chamber (30) is pressurized by a fluid, in particular compressed air, in order to blow the expandable tool (20) into the container (30).

4. The method in accordance with any of claims 1 to 3, characterized in that a vacuum is applied to the interior of the expandable tool (20) in order to evert the expandable tool (20).

5. The method in accordance with claims 4 and 2, characterized in that a vacuum is applied to the pressure chamber (30) in order to apply a vacuum to the expandable tool (20).

6. The method in accordance with any of claims 1 to 5, characterized in that the expandable tool (20) has a contour that is geometrically similar to the contour of the finished container (30) with a scaling factor of greater than 50%, preferably greater than 80%, in particular greater than 90% and preferably between 94% and 98%, and in particular has a congruent contour with respect to the container (30).

7. The method in accordance with any of claims 1 to 6, characterized in that an overpressure is applied to the expandable tool (20) for blowing in the expandable tool (20).

8. The method in accordance with any of claims 1 to 7, characterized in that the expandable tool (20) has a thickened portion (23) on its neck (22), on which thickened portion it is held.

9. A method for reducing the water content in a fiber-based container (30), comprising the steps of:

- providing a wet fiber-based container (30) in a mold (50),

- introducing an expandable tool (20) into the wet fiber-based container (30), the latter being provided in an everted form for introducing the expandable tool(20) and being blown into the container (30) through its own neck (22), in particular according to a method of any of claims 1 to 8,

- expanding the expandable tool (20).

10. The method in accordance with claim 9, characterized in that the expandable tool (20) is expanded by introducing a fluid, in particular compressed air.

11. The method in accordance with either claim 9 or claim 10, characterized in that a vacuum is applied to the expandable tool (20) after the expansion thereof so that it can be removed from the container (30).

12. The method in accordance with claim 11, characterized in that the expandable tool (20) is turned inside out for removal by the vacuum.

13. A device for introducing an expandable tool (20) into a container (30), in particular according to a method of any of claims 1 to 8, said device having a mold (50) for receiving a wet fiber-based container (30), characterized in that the device has a pressure chamber (40) that is arranged opposite the mold (50).

14. The device in accordance with claim 13, characterized in that an expandable tool (20) having a neck (22) is arranged within the pressure chamber (40), wherein an opening on the mold (50) for a container neck (32) and the neck (22) are arranged opposite one another.

15. The device in accordance with claim 13 or 14, characterized in that the pressure chamber (40) is connected to a device for producing an overpressure and/or a vacuum.

16. The device in accordance with any of claims 13 to 15, characterized in that the pressure chamber (40) has an inner diameter that is smaller than an outer diameter of the expandable tool in an everted form.

Drawing