DE102008063937A1 - Method and device for producing a tubular element - Google Patents

Abstract

A method for producing a tubular element (1), in particular a filter element for a motor vehicle, comprises the steps of: forming a tubular base element (1A) of filter material; Folding the filter material on at least two first portions (4A) of a common first peripheral line (4) towards a central axis (M) of the base member (1A) by at least two, preferably opposing, first folding knives (6A, 6B) to produce first ones Circumferential folds (4A); Folding the filter material on at least two second portions (5A) of a common second circumferential line (5) which runs at a predetermined distance (D) parallel to the first peripheral line (4), towards the central axis (M) by at least two, preferably opposing second folding blades (7A, 7B) for producing second circumferential folds (5A), the second portions (5A) being displaced (a) from the first portions (4A) on the respective peripheral line (4, 5); and holding and guiding the circumferential folds (4, 5) along the central axis (M) through the first and second folding knives (6A, 6B, 7A, 7B) to form upsets (9) between the first and second circumferential folds (4, 5) ,

Description

Technical area

The The present invention relates to a manufacturing method for a tubular element, in particular for a filter element for motor vehicles, for. B. as a cabin filter or intake air filter. Furthermore, the invention relates to a device for producing a corresponding filter element.

filter elements are used to filter fluid flows or gaseous Media, for example for filtering an air flow, the vehicle interior or the engine of a motor vehicle is supplied. The present invention and the hers underlying problems are essentially below for a filter element for filtering air for described the interior of a motor vehicle. Such filters will be in the following also briefly as car interior air filter or also cabin filter or cabin air filter referred to.

The increasing air pollution, especially in large cities, in connection with the use of air conditioning systems in the vehicle requires that from the outside into the interior of a motor vehicle Guided and treated air cleaned by means of suitable filters becomes. For this purpose, for example, come particulate filter, odor filter or combinations thereof, which in the Air contains suspended particles, particles and odors The sucked raw air filter out or absorb as well as possible should.

Desirable is also an inexpensive production corresponding Filter.

State of the art

Usually filters are used, which are one between two sidebands have fixed fold pack. Corresponding filters are included usually a solid cuboid geometry. In the Production, the fold pack is first folded and then glued on the side bands for folding fixation.

Often, however, more irregular shapes for, for example, air filters are desired to use the existing space in the engine or vehicle interior as efficiently as possible. There are therefore flexible, tubular filter elements have been developed, as for example in the DE 10 2006 047 030 A1 are described. Such filter elements can have complex folds that allow a filter material sheet to be folded into a tubular filter element. Due to the complex arrangement of folds and wrinkle orientations among one another, production machines set up for cuboid geometries and the corresponding methods are no longer usable.

In front In this background, the present invention has the object underlying, a method and an apparatus for producing a Specify loop-shaped filter element.

Disclosure of the invention

These Task is by a manufacturing method according to claim 1 solved. Furthermore, the object is achieved by a device solved with the features of claim 13.

One Method for producing a tubular element, which in particular a filter element for a motor vehicle In this case, the steps include: forming a tubular Base element made of filter material. Fold the filter material at least two first portions of a common first circumference toward at least one central axis of the base member two, preferably opposing, first folding knife for generating first circumferential folds. Fold the filter material at least two second portions of a common second circumferential line, which at a predetermined distance parallel to the first circumferential line runs, at least towards the central axis two, preferably opposing, second folding knife for generating second circumferential folds. The second sections are doing opposite to the first sections on the respective ones Circumference shifted. Furthermore, a holding and guiding each other done the circumferential folds along the central axis through the first and second folding knife for forming upset folds between the first and second circumferential folds.

at The method is a tubular base element, which for example, by a provided filter material sheet, its two opposite edges with each other connected, processed. The base element corresponds essentially a hose made of filter material, into which no Folds were imprinted. It is also possible, the filter material sheet by impressing predetermined Wrinkles and / or wrinkle orientations for to pretreat the circumferential or upsetting folds.

In the method thus results in a variety of circumferential folds, which are made on parallel circumferential lines. The circumferential fold lines may, but need not, be at regular intervals along the central axis of the base or even finished filter element are made on the surface of the tubular base element.

A Apparatus suitable for carrying out the manufacturing process comprises for producing a tubular filter element a guide means for a tubular Base member having a central axis, wherein the guide means is provided along a longitudinal axis of the device. The device has a first folding knife set with at least two folding knives for folding the base element, which is perpendicular to the longitudinal axis on a common cross-section, preferably radially, movable are. It is a second folding knife set with at least two folding knives provided for folding the base element, which is perpendicular to the longitudinal axis on a common cross-section, preferably radially, movable are. The first and the second Faltmessersatz are against each other a predetermined angle set shifted about the longitudinal axis.

through The device is possible by the given Rake angle the above-described, shifted circumferential folds to produce by means of the folding knife of the two Faltmessersätze.

When Guide device, for example, a rod is conceivable on which the base element is attachable. It can also be one be provided tubular portion into which the base member inserted is. A corresponding tubular section does not have to be formed integrally, but also several Include pipe segments, which then partially form a pipe jacket.

through a holding device, along the longitudinal axis of Device is provided, can folds of the folded Base element after passing through the first and second Faltmessersatzes along the longitudinal axis, at least temporarily be fixed. That is, the circumferential folds are, preferably from the inside of the tubular element, fixed.

The Folding knives of a respective Faltmessersatzes are usually simultaneously moved radially, so that the circumferential folds on a respective circumferential line are generated simultaneously. By folding the circumferential folds using the folding knife, can between the first and second sections on a respective perimeter further Sections with further circumferential folds arise. On a perimeter have the further circumferential folds opposite the (first) Circumferential folds opposite folding orientations on.

Becomes the method of making a simple tubular Element used, for example, arise on a respective Peripheral line two circumferential folds a first orientation and two further circumferential folds one of the first orientation opposite Orientation. A respective circumferential line of the tubular base element usually has an even number of folding sections, each adjacent or subsequent folding sections have opposite fold orientations along the circumference.

at An optional preparatory manufacturing step becomes perimeter embossing applied to a provided filter material sheet.

About that In addition, it is possible diagonal compression embossing provide, wherein a plurality of parallel, along a respective peripheral base element encircling Circumferential embossing on the material sheet arise and the Circumferential embossing by diagonal compression embossing are connected. After folding using the folding knife, which is essentially only radially the filter material in the direction of the central axis impress, arise along a respective perimeter Corners of the element, on each of which two circumferential folds opposite Orientation and two compression folds of the same orientation converge. The compression folds allow compression along the central axis.

To folding the filter material at the first and second circumferential lines Preferably, a folding of the filter material takes place at least two third sections of a common third circumferential line, which also at a predetermined distance parallel to the second Circumference runs. The folding takes place in the direction to the central axis through which at least two first folding knives for generating third circumferential folds. The third sections are opposite to the second sections on the respective ones Circumference shifted. The displacement or rotation of the third For example, sections opposite the second sections can be over adjusted the set angle of a corresponding manufacturing device become. The angle is a measure of the Rotation of first and second folding knife sets against each other.

Even though third and further circumferential folds can be made, the method requires only first and second folding knives. Because the first folding knives can be attached to the second folding knives outside the base element along the central axis over be guided.

By feeding the folding knife to one another, ie a reduction of the distance along the Longitudinal or central axis between the folding blades of different rates, for example, the compression folds, which are then fixed by a suitable holding device, such as a foam block that holds the inwardly directed circumferential folds.

Appropriate Folding knives are thus alternately as a folding means and as a holding means used. By the movement of the folding knife along the longitudinal axis a corresponding device or the central axis of the on the Longitudinal axis of the present filter element or base element, becomes the tubular base element from the outside provided with folds and simultaneously along the longitudinal axis promoted the device.

In some embodiments of the manufacturing device is therefore at least one of the folding knife sets along the Slidably arranged longitudinal axis. The folding knife of a Faltmessersatzes can compete against each other for a predetermined Knife angle to be moved around the longitudinal axis. The number The folding knife per folding knife set should be at least two.

The Device may also have actuators for moving the folding knife radially with respect to the longitudinal axis. there it is possible to control the actuators such that the Folding knife of a respective Faltmessersatzes simultaneously radial to be moved.

In In one embodiment, the manufacturing device for a tubular filter element further a control device on which the movements of the folding knife controls such that a manufacturing process as described above, is carried out.

Further advantageous embodiments and refinements of the invention are Subject matter of the subclaims and those described below Embodiments.

Brief description of the drawings

The The invention will be further described below with reference to several embodiments explained in more detail with reference to the accompanying figures. It shows:

1 a perspective view of a tubular filter element;

2 an embodiment of a filter material sheet with possible folding lines;

3 . 4 : perspective views of folding operations with folding blades during the manufacture of a tubular filter element;

5 . 6 : Longitudinal and cross-sectional views of folding and holding operations during the manufacture of a tubular filter element;

7 - 9 FIG. 3: longitudinal sectional views of folding and holding processes during the production of a tubular filter element; FIG.

10 a perspective view of an embodiment of a manufacturing device for tubular filter elements;

11 a longitudinal sectional view of the embodiment of a manufacturing device for tubular filter elements; and

12 FIG. 3 is a cross-sectional view of one embodiment of a tubular filter element manufacturing apparatus. FIG.

In The figures are the same or functionally identical elements, provided nothing else is indicated, provided with the same reference numerals Service.

Embodiment (s) of the invention

The 1 shows a perspective view of a tubular filter element. The filter element 1 is made of a filter material, such as a matted flow material. A fluid to be filtered enters, for example, in the interior of the tubular filter element 1 a, passes through the filter fluid and exits as purified fluid to the outside. That in the 1 exemplified filter element 1 has a central axis M, around which a tube of a filter material sheet is formed, which can be compressed and flexibly rotated due to the provided folds. The filter element 1 in the 1 has a substantially octagonal cross-section, with folds, each provided along a circumference.

The corresponding circumferential folds 4A . 4B On the one hand have a Faltorientierung to the central axis M down and on the other hand circumferential folds 4B who have an orientation to the outside. The filter element 1 has a plurality of corresponding circumferential folds, of which only the two adjacent 4A . 4B . 5A . 5B are provided with reference numerals. Furthermore, compression folds connect 9 the circumferential folds 4A . 4B . 5A . 5B different circumferential lines with each other. At the corners 21 each lead to two circumferential folds 4A . 4B . 5A . 5B different orientation and two compression folds to each other 9 ,

The 2 shows a filter material sheet 2 , which by suitable folding or folding method to that in the 1 shown filter element 1 gefer can be taken. In the presentation of the 2 is a filter material sheet 2 with a lower edge section 3A and an upper edge portion 3B shown. In the manufacture of a filter element according to the 1 First, a tubular base element is formed by the two edge portions 3A . 3B connected together, such as glued.

The dashed and solid lines in the 2 on the filter material sheet 2 correspond to the later folds in the executed filter element 1 , Solid lines mean in the 2 a convolution outward with respect to the tubular or tubular interior of the then present base element, and dotted lines correspond to an inward, so made in the direction of the central axis folding.

In order to conveniently prepare a filter material sheet for further processing, the folds to be made can be punched into the filter material sheet 2 along in the 2 shown lines or dotted lines are made. In the following, it is assumed in the description of the further method steps that a previously made embossing of the filter material is transformed into a corresponding folding. Therefore, the terms circumferential folding and circumference are synonymous partly synonymous used.

In the 2 is, for example, a first perimeter 4 and a second circumferential line 5 indicated. The two circumferential lines are at a distance D from each other in parallel. Along the first perimeter 4 are first sections 4A provided and more sections 4B , Each adjacent sections 4A . 4B have different folding orientations. Similarly, the adjacent circumferential line 5 sections 5A . 5B on, along which according to the indicated solid or dotted lines a folding is to take place.

In order to simplify the folding in the later folding step by means of suitable folding knives, a corresponding embossing on the filter material or the filter material sheet can be preparatory 2 be made. Furthermore, compression folds 9 provided, which can also be imprinted accordingly. In principle, the subsequent folding can also take place without a previous embossing of the material.

Although in the 1 and 2 and in the following description of the method steps, the production of an embodiment of a filter element 1 according to the 1 is explained, other geometries can be achieved by the manufacturing process. In particular, the number of folding sections of different orientation 4A . 4B . 5A . 5B along a perimeter 4 . 5 may vary. In the DE 10 2006 047 030 A1 and the local ones 3 . 5 . 7 and 9 , Alternative filter elements are shown with different cross-sectional areas, which can be produced by the method described here. The manufacturing method described below is therefore also suitable for the realization of the corresponding 1 deviating, geometries.

For the production of the filter element 1 First, a base member is provided as a tubular member. This can be done, for example, by connecting the two edge sections 3A . 3B in the 2 illustrated filter material sheet 2 be achieved. Subsequently, a folding takes place along a respective circumferential line 4 . 5 by suitable folding knife.

In the 3 and 4 corresponding perspective representations are given. The 3A shows in generalized form the basic element 1A having a central axis M, and by two folding blades 6A . 6B , which are arranged opposite each other, are pressed inwards. The movements of the folding knife 6A . 6B are indicated by the double arrows. The respective edge of the folding knife runs in such a way that the base element 1A inward, ie in the direction of the central axis M along a common circumferential line (for example, the circumferential line 4 in the 2 ) is pressed or folded. This results in circumferential folds 4A , as well as circumferential folds 4B ,

In the 4 is a follow-up step with two further, also opposing folding blades 7A . 7B represented. On a representation of the still existing first folding knife 6A . 6B as they are in the 3 is shown in the 4 waived. The two folding knives 7A . 7B are opposite the folding knives 6A . 6B arranged twisted about the central axis M. This ensures that at the points of the circumference of the tubular element 1A on which the folds 4A have been made shifted by the distance D, circumferential folds 5B arise, which have an opposite orientation.

By impressing or folding the filter material by means of the second folding knife 7A . 7B , is along the perimeter 5 , achieves a circumferential crease, with respect to the orientation, as in the 2 is indicated by the dotted and solid lines corresponds. As in the others 5 - 9 is explained in more detail, hold the two Faltmessersätze 6 respectively. 7 during the folding process, on the one hand, the resulting circumferential folds 4A . 4B . 5A . 5B and lead them together at the same time, making the base element 1A along the central axis is compressed. there arise the compression folds 9 ,

In the 5 is a longitudinal and cross-sectional view of the first folding operation by means of the first folding knife 6A . 6B shown in more detail. The 5A shows a longitudinal section, where left the folding knife 6A . 6B the tubular or tubular base element 1A it is shown which right the folding knife 6A . 6B has already been provided with circumferential and compression folds. The folded base element structure or the finished filter element is denoted by the reference numeral 1B Mistake.

One recognizes that in the orientation of the 5A the first two folding knives 6A . 6B , which are arranged opposite to each other, the base element 1A depress or fold inwardly along the intended folding orientation at circumferential portions along the circumferential line. The 5B shows a cross-sectional view with a representation of the two folding knife 6A . 6B and the base element 1A , The cross section is along the circumference 4 , It can be seen that the two folding knives 6A . 6B are arranged opposite to each other or about the central axis M around, rotated by the angle α.

Around To achieve different geometries, three or three more folding knives are used, each one preset Angle are shifted or twisted around the central axis.

The 6 shows a longitudinal and cross-sectional view during the following process step, in which the second folding knife 7A . 7B as they are in the 4 are indicated, make more circumferential folds. The 6A shows the same longitudinal section as the 5A but with the second folding knives 7A . 7B rotated by 90 ° along the central axis M in the direction of the central axis M, the base element 1A press in or fold in.

In cross section, which in the 6B is shown, it can be seen that the angle β, the rotation of the two Faltenmesserpaare 6A . 6B . 7A . 7B indicating 90 °. One speaks also with the two first Faltmessern and / or the two second Faltmessern of in each case a Faltmessersatz. One recognizes thus in the 6A that as it is already in the 2 is shown, at the distance D parallel circumferential folds in the base element 1A be embossed.

The 7 again shows a longitudinal section of the situation following in the 6A illustrated longitudinal section during manufacture. The two folding knife sets 6 . 7 are guided to each other, ie, the distance from each other along the central axis M is reduced. This also results in a compression fold 9 , The two Faltmesserpaare 6A . 6B and 7A . 7B Keep the resulting circumferential folds and guide them to each other. The resulting folding geometry can be optional, as it is in the 6A is indicated by a holding device 6 be fixed. As a holding device, for example, a foam tube, which has been introduced from the filter element inside, so from the real side of the base member in the already folded the folds, is introduced. By a corresponding clamping or adhesion, the folding edges can be at least partially held.

In the further manufacturing step, in the 8th is shown, the first folding knife 6A . 6B detached from the resulting folds, along the central axis in the orientation of 7 . 8th at the folding knives 6A . 6B moved to the left, so that a further circumferential folding can be made. Ie. the first folding blades are on the outside, past the second folding blades, to another spaced circumferential line 8th brought so again there Umfangsfaltabschnitte 8th can be generated.

In the manufacturing process, therefore, each folding knife along a longitudinal or central axis of the resulting filter element 1B guided and press or fold the base element 1A repeatedly.

In the 9 a further longitudinal section is shown, in which subsequently the two Faltmesserpaare 7A . 7B . 6A . 6B be led to each other again, so that further compression folds 9 arise and at the same time the folded filter element 1B in the orientation of 9 pushed to the right or transported. Again, in the 9 presented the situation in which the two Faltmesserpaare 7A . 7B . 6A . 6B along the longitudinal axis are brought together and thus cause the compression of the filter element.

The 10 - 12 show perspective and cross-sectional views of a manufacturing apparatus used to carry out, with respect to 1 to 9 explained, manufacturing process is suitable. The perspective view of a manufacturing device 10 in the 10 shows a frame arrangement 14 . 15 . 16 Among other things, to hold a central guide rod 11 along a longitudinal axis L of the device 10 is provided. This is for example a holder 12 intended. The guide device or guide rod 11 serves to hold the unfolded base element. This is in the longitudinal sectional view of 11 to recognize. The holder 12 carries the guide rod 11 to which the base element 1A and after passing through a range of folding blades, the processed filter element 1B is plugged.

To get the best possible guidance along the Longitudinal axis L for the filter or base element is also a tubular portion 13 provided, the several pipe segments 13A . 13B . 13C includes and the tubular base member 1A additionally keeps from the outside. This is for example in the 10 to recognize where three pipe segments 13A . 13B . 13C from the first frame 14 are attached from.

In the cross-sectional view of 12 that, in essence, in the 3 and 4 is a first set of folding knives 6A . 6B , which are movable in the vertical direction, and a second Faltmessersatz with two folding blades 7A . 7B which are movable in the horizontal direction. The respective folding knife 6A . 6B . 7A . 7B are via actuator devices 17A . 17B . 18A . 18B driven. The actuator devices are, for example, as in the 11 is indicated via a control device 21 Programmable, controlled in terms of their movements.

To include a shift or movement of the folding knife 6A . 6B . 7A . 7B to allow, as it is in the longitudinal section of the 11 it can be seen, at least one Faltmessersatz 6A . 6B , by further actuator devices 19A . 19B displaceable along the longitudinal axis L. As a result, the control device can coordinate to hold and combine the resulting circumferential folds.

By means of the device 10 are therefore only, taking advantage of the folding knife 6A . 6B . 7A . 7B the circumferential and upsetting folds are embossed or folded into the tubular base element and at the same time along the longitudinal axis through the device 10 driven. Thus, in the illustration of the 11 on the left the folding knife 6A . 6B the unfolded base element 1A available and right, after passage of the folding procedure, the finished tubular filter element 1B available.

The proposed procedure during the manufacturing process and its implementation as a manufacturing device requires a minimum number of folding blades, which are coordinated in their movement. For example, in the 1 To produce shown filter element, only two Faltmessersätze with two folding knives are required. It can therefore be a fast and efficient production of a corresponding filter element.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006047030 A1 [0006, 0045]

Claims (22)

Method for producing a tubular element ( 1 ), in particular a filter element for a motor vehicle, comprising: - forming a tubular base element ( 1A ) of filter material; Folding the filter material on at least two first sections ( 4A ) a common first perimeter ( 4 ) towards a central axis (M) of the base element ( 1A ) by at least two, preferably opposing, first folding knife ( 6A . 6B ) for producing first circumferential folds ( 4A ); Folding the filter material on at least two second sections ( 5A ) a common second circumferential line ( 5 ), which at a predetermined distance (D) parallel to the first circumferential line ( 4 ), in the direction of the central axis (M) by at least two, preferably opposing, second folding knife ( 7A . 7B ) for producing second circumferential folds ( 5A ), the second sections ( 5A ) compared to the first sections ( 4A ) on the respective circumference line ( 4 . 5 ) are shifted (α); and holding and guiding the circumferential folds ( 4 . 5 ) along the central axis (M) through the first and second folding blades ( 6A . 6B . 7A . 7B ) for forming compression folds ( 9 ) between the first and second circumferential folds ( 4 . 5 ). The method of claim 1, further comprising: fixing the circumferential folds ( 4 . 5 ) by means of a about the central axis (M) arranged holding device ( 20 ) from an inside of the tubular element ( 1B ) ago. Method according to claim 1 or 2, wherein, by folding and holding the circumferential folds ( 4 . 5 ) between the first or second sections ( 4A . 5A ) on a respective circumferential line ( 4 . 5 ) further sections ( 4B . 5B ) with further circumferential folds ( 4B . 5B ), wherein the further circumferential folds ( 4B . 5B ) one against the circumferential folds ( 4A . 5A ) have opposite orientation. Method according to claim 3, wherein on a respective peripheral line ( 4 . 5 ) two circumferential folds ( 4A . 5A ) of a first orientation and two further circumferential folds ( 4B . 5B ) are provided one of the first orientation opposite orientation. Method according to claim 3 or 4, wherein along a respective peripheral line ( 4 . 5 ) Corners ( 21 ) of the element ( 1B ) arise at each of which two circumferential folds ( 4A . 4B ) opposite orientation and two compression folds ( 21 ) of the same orientation. The method of any of claims 1-5, further comprising: providing a filter material sheet ( 2 ). The method of claim 6, further comprising: embossing predetermined fold progressions and / or fold orientations for the circumferential and / or upsetting folds into the filter material sheet ( 2 ). The method of claim 6 or 7, further comprising: connecting two to the filter material sheet ( 2 ) opposite edges ( 3A . 3B ) of the filter material sheet ( 2 ) for forming the tubular base element ( 1A ) such that a plurality of parallel ones along a respective circumference of the base element ( 1A ) circumferential embossing ( 4 . 5 ) and the circumferential embossings connecting diagonal compression stampings ( 9 ) arise. Method according to claim 8, wherein the peripheral embossings ( 4 . 5 ) such embossing sections ( 4A . 4B ) that abutting embossing sections ( 4A . 4B ) of the same circumference ( 4 ) have opposite orientations. The method of any one of claims 1-9, further comprising: folding the filter material at at least two third portions of a common third circumferential line ( 8th ), which at a predetermined distance (D) parallel to the second circumferential line ( 5 ), in the direction of the central axis (M) through the at least two first folding knives ( 6A . 6B ) for producing third circumferential folds ( 8th ), the third sections being opposite the second sections on the respective peripheral line (FIG. 5 . 8th ) are shifted (β). Method according to claim 10, wherein the first folding knives ( 6A . 6B ) on the second folding blades ( 7A . 7B ) outside the base element ( 1A ) are passed along the central axis (M). A method according to claim 10 or 11, wherein the first sections and the third sections are along the respective peripheral line (Fig. 4 . 8th ) are mutually unshifted. Contraption ( 10 ) for producing a tubular filter element ( 1 ) with: - a management facility ( 11 ) for a tubular base element ( 1A ), which has a central axis (M), along a longitudinal axis (L) of the device ( 10 ); - a first folding knife set with at least two folding knives ( 6A . 6B ) for folding the base element ( 1A ) which are movable perpendicular to the longitudinal axis (L) on a common cross-section; and - a second folding knife set with at least two folding knives ( 7A . 7B ) for folding the base element ( 1A ) which are movable perpendicular to the longitudinal axis (L) on a common cross-section; - Wherein the first and second Faltmessersatz are shifted from each other by a predetermined set angle (β) about the longitudinal axis (L). Contraption ( 10 ) according to claim 13, wherein the guide device comprises a rod ( 11 ) to which the base element ( 11A ) can be plugged. Apparatus according to claim 13 or 14, wherein the guide means comprises a tubular ( 13 ) Section into which the base element ( 1A ) is insertable. Contraption ( 10 ) according to claim 15, wherein the tubular portion comprises a plurality of pipe segments ( 13 ), which at least partially form a pipe jacket. Contraption ( 10 ) according to any one of claims 13-16, wherein at least one of the Faltmessersätze along the longitudinal axis (L) is displaceable. Contraption ( 10 ) according to any one of claims 13-17, wherein the folding knives ( 6A . 6B . 7A . 7B ) of a respective Faltmessersatzes against each other by a predetermined blade angle (α) about the longitudinal axis (L) are shifted. Contraption ( 10 ) according to any one of claims 13-18, wherein actuators ( 17A . 17B . 18A . 18B ) for moving the folding knife ( 6A . 6B . 7A . 7B ) are provided radially with respect to the longitudinal axis (M). Contraption ( 10 ) according to one of claims 13-19, wherein a holding device ( 20 ) is provided along the longitudinal axis (L) in such a way that the holding device ( 20 ) Convolutions of the folded base element ( 1B ) after passing through the first and second Faltmessersatzes entlag the longitudinal axis (L) at least temporarily fixed. Contraption ( 10 ) according to any of claims 13-20, wherein the folding knives ( 6A . 6B . 7A . 7B ) of a respective Faltmessersatzes be moved radially simultaneously. Contraption ( 10 ) according to one of claims 13-21, wherein a control device ( 21 ) is provided, which the movements of the folding knife ( 6A . 6B . 7A . 7B ) such that a method according to any one of claims 1-12 is performed.