TECHNICAL FIELD

The invention relates to a method and a machine for manufacturing a structure of fiber material. Especially, the fiber structure may be in the form of a sheet- or weblike structure. The term fiber material relates to a lignocellulose-containing material.

According to one example, the structure of fiber material forms a hollow board material, which in this disclosure means a material comprising two sheets with an intermediate distance material. The hollow board material may be used as packaging material for protecting goods, such as furniture, such as bookshelves, shelves, doors, tables etc. during transport.

BACKGROUND

WO2012/048738 discloses a method and a machine for manufacturing a structure of fiber material in the form of a hollow board material. The method comprises providing material for a first sheet from a first reel via a first guide roller towards an output lane; providing material for a second sheet from a second reel via a second guide roller towards the output lane; and providing material for distance members from a third reel towards the output lane. The distance members are formed by a plurality of separate strips introduced between the first sheet and the second sheet in an upright position perpendicular to the sheets for maintaining a distance between the sheets. Further, the strips are spaced in a transverse direction of the output lane. Further, each strip is arranged in a meandering pattern between the first sheet and the second sheet in the direction of the output lane. Further, the method comprises the step of applying an adhesive on opposite edges of the strips such that adhesion to the first sheet and the second sheet is enabled. First and second guide rollers are adapted to press the first sheet and the second sheet to the opposite edges of the strips, respectively, such that the first sheet and the second sheet are adhered to the strips.

SUMMARY

An objective of the invention is to provide a method, which creates conditions for a high pace of manufacturing a structure of fiber material while still providing a strong construction of the fiber structure. The objective is achieved by a method according to claim 1. Thus, it is achieved by a method for manufacturing a structure of fiber material, wherein the method comprises the steps of - feeding a first web of fiber material along a processing path and processing the first fiber web during the feeding along the processing path by: creating a series of fold indications in the first fiber web, and folding the first fiber web at the fold indications thereby forming a folded configuration. According to one aspect, the first web of fiber material is a material made from cellulose fiber, such as wood pulp. Further, the fiber material may be produced from recycled material.

According to a further aspect, the first web of fiber material has such an internal structure and thickness that it is relatively rigid and prone to partially crack rather than smoothly curve when subjected to bending. The first web of fiber material may have a thickness in the interval 0,5 - 2,0 mm, especially above 0,6 mm, preferably less than 1,5 mm and more preferably less than 1,2 mm. According to one example, the first web of fiber material has a thickness in the interval 0,7 - 1,0 mm.

According to a further aspect, the term web is a long sheet or strip of solid material wound on a roll. The web material may have a continuous upper external main surface and a continuous lower external main surface. The web is thin in comparison to its length and breadth. Such a web may also be termed continuous in its longitudinal direction and transverse direction.

According to a further aspect, the processing path defines a feeding direction of the first web of fiber material in a machine, wherein the processing path may change direction one or several times at guide rollers or other guide means.

According to a further aspect, the first web of fiber material is continuously fed along the processing path, wherein the steps of creating fold indications and folding are performed during the continuous feeding. According to a further aspect, the fold indications form a series of weakened regions. Such a fold indication may be continuous in its longitudinal direction. The fold indication may then extend only a portion of the thickness of the first fiber web, such as for example halfway through the material, at least along a section of the fold indication in its longitudinal direction. According to an alternative, the fold indication is discontinuous in its longitudinal direction. Further, spaced fold indication sections in the longitudinal direction of the fold indication may extend throughout the thickness of the first fiber web. According to one example, the fold indications extend along straight lines and in parallel with each other.

According to one example, the fold indications are continuous in their longitudinal direction. Further, the fold indications extend only a portion of the thickness of the first fiber web. According to one example the fold indications have an extension from halfway through the thickness of the first fiber web up to about 90% of the thickness of the first fiber web. According to a preferred example, the fold indications have an extension from 60% through the thickness of the first fiber web up to about 80% of the thickness of the first fiber web.

According to a further example, all fold indications from a first side surface of the first fiber web extend to the same extent through the thickness of the first fiber web. Further, all fold indications from a second side surface of the first fiber web extend to the same extent through the thickness of the first fiber web. According to one example, the fold indications from the first side surface of the first fiber web extend to the same extent through the thickness of the first fiber web as the fold indications from a second side surface of the first fiber web. Such a design creates conditions for a symmetrical final product in that the structure of fiber material will have the same characteristics in opposite directions perpendicular to a main extension plane of the structure of fiber material.

According to a further aspect, the step of folding the first fiber web at the fold indications thereby forming a folded configuration comprises folding the first fiber web at the fold indications so that a series of planar sheet segments of the first fiber web are spaced by the fold indications and so that two adjacent sheet segments in the series extend at an angle relative to one another in a cross section of the first fiber web. According to one example, two adjacent sheet segments in the series extend at a sharp angle relative to one another in a cross section of the first fiber web. According to a further aspect, the folded configuration forms a regular pattern. The term "regular" in this context is meant to refer to the fact that the series of angled planar sheet segments alternate with generally the same repeating shape and size in one direction of the first fiber web.

According to a further aspect, an inelastic deformation is caused to the first fiber web. This prevents the first fiber web from returning to its original shape. However, if the tension is released, the first fiber web may tend to spring back somewhat from its folded configuration, recovering only a portion of the stretch and bending that has occurred. The method therefore may be adapted for maintaining the first fiber web in its folded configuration after the folding until a next processing step.

According to a further aspect, the first fiber web has such a shape in the folded configuration that the apex of each fold indication is cracked/split to some extent. Such a partial crack/split is distinct from the first fiber web being formed along a radiused or arc shaped curve.

According to one embodiment, the step of creating fold indications involves creating depressions in the first fiber web, which depressions form the fold indications. It creates conditions for a secure folding of the first fiber web for creating a desired folding configuration in the next step. According to one aspect, such depressions may be formed by cutting and/or compressing the material. According to a further embodiment, the step of creating the fold indications is performed so that every second fold indication is formed from a first side of the first fiber web and every second fold indication is formed from a second side of the first fiber web opposite the first side. It creates conditions for the first fiber web to be securely angled at a fold indication so that the fold indication is on an inner side of the material for creating a desired folding configuration in the next step. Especially, it creates conditions for achieving a folding configuration of a zigzag pattern in cross section.

According to a further embodiment, the step of folding the first fiber web in a folded configuration involves folding it in a zigzag pattern comprising a series of planar sheet segments and wherein two adjacent sheet segments in the series are connected via a sharp angle at one of the fold indications. The term zigzag pattern may in this context be defined as comprising a series of sharp alternating turns in one direction of the web. According to one example, the zigzag pattern is in a cross section in parallel with the longitudinal direction of the first fiber web and in a height direction of the first fiber web. According to another example, the zigzag pattern is in a cross section perpendicular to the longitudinal direction.

According to a further embodiment, the step of folding the first fiber web in a folded configuration involves effecting the first fiber web in opposite directions so that the zigzag pattern is formed. Especially, the first fiber web may be pushed at a fold indication in a direction transverse to a plane of the first fiber web for achieving an angled configuration of two adjacent sheet segments on opposite sides of the fold indication. According to one aspect, the step of folding the first fiber web in a folded configuration involves effecting the first fiber web in opposite directions in an alternating manner so that the zigzag pattern is formed.

According to a further embodiment, the method comprises the step of feeding a second web of fiber material to a position where it meets the first fiber web downstream of the folding of the first fiber web in the processing path of the first fiber web, and the step of adhering outer portions of a first set of folds of the first fiber web to a surface of the second fiber web. According to one example, the second fiber web is fed in parallel with the first fiber web at the meeting position.

According to one aspect, the second fiber web has a planar configuration when reaching the meeting position. According to one aspect, the second fiber web has a continuous surface in a longitudinal direction and transverse direction, which surface faces the first fiber web at the meeting position. According to one aspect, the second fiber web is of the same material composition as the first fiber web. According to one aspect, the second fiber web is of the same material thickness as the first fiber web.

According to a further development of the last-mentioned embodiment, the method comprises the step of maintaining the first fiber web in the folded configuration from the folding of the first fiber web to the meeting position. Some materials have a tendency to spring back somewhat from its folded configuration after folding and this step prevents the first fiber web from such spring back tendency. According to a further embodiment, the method comprises the step of moving the first fiber web in an arcuate path in the folded configuration from the folding of the first fiber web to the meeting position. Especially, the first fiber web may be moved along the periphery of a rotating roll in the folded configuration from the folding of the first fiber web to the meeting position. Further, the rotating roll may have a series of alternating cavities and crests matching the pattern of the folded configuration for maintaining the first fiber web in the folded configuration.

According to a further embodiment, the method comprises the step of applying an adhesive on one of the first fiber web and the second fiber web and adhering the first fiber web to the second fiber web by pushing the first fiber web and the second fiber web towards each other. In this way, the first fiber web may be rigidly attached to the second fiber web.

According to a further embodiment, the method comprises the step of feeding a third web of fiber material to a position where it meets the first fiber web downstream of the folding of the first fiber web in the processing path of the first fiber web, and the step of adhering outer portions of a second set of folds of the first fiber web to a surface of the third fiber web, wherein the second set of folds point in an opposite direction relative to the first set of folds. According to one example, the third fiber web is fed in parallel with the first fiber web at the meeting position.

According to one aspect, the method comprises the step of feeding the third web of fiber material to a position where it meets the first fiber web downstream of the position where the first fiber web is adhered to the second fiber web in the processing path.

According to one aspect, the third fiber web has a planar configuration when reaching the meeting position. According to one aspect, the third fiber web has a continuous surface in a longitudinal direction and transverse direction, which surface faces the first fiber web at the meeting position. According to one aspect, the third fiber web is of the same material composition as the first fiber web. According to one aspect, the third fiber web is of the same material thickness as the first fiber web.

According to a further embodiment, the step of creating a series of fold indications in the first fiber web is performed so that the fold indications are spaced from each other in a longitudinal direction of the first fiber web and extend in a transverse direction relative to the longitudinal direction of the first fiber web.

According to an alternative to the last-mentioned embodiment, the step of creating a series of fold indications in the first fiber web is performed so that the fold indications extend in a longitudinal direction of the first fiber web and are spaced from each other in a transverse direction relative to the longitudinal direction of the first fiber web.

In this way, a hollow fiber structure may be formed, wherein the first fiber web in the folded configuration forms a distance material between the second fiber web and the third fiber web.

According to a further embodiment, creating the series of fold indications in the first fiber web comprises cutting the first fiber web by means of at least one first sharp object acting on a first side surface of the first fiber web against a hard counter surface on a second side of the first fiber web.

The term ’’hard” means that the surface is non-resilient. According to one example, the hard surface is convex in a region facing the sharp object.

The surface material of the counter force surface may be formed at least partly by a steel, such as a tool steel, for achieving the hard surface. The steel surface may be a hardened surface, ie it has been subjected to hardening during production.

According to a further development of the last-mentioned embodiment, creating the series of fold indications in the first fiber web comprises cutting the first fiber web by means of at least one second sharp object acting on the second side surface of the first fiber web against a hard counter surface on the first side of the first fiber web. This embodiment creates conditions for creating a symmetrical final product in that the structure of fiber material will have the same characteristics in opposite directions perpendicular to a main extension plane of the structure of fiber material.

According to a further development of the last-mentioned embodiment, the method comprises the step of cutting the first fiber web to substantially the same penetration depth by the at least one first sharp object as by the at least one second sharp object. It creates further conditions for a symmetrical final product in that the structure of fiber material will have the same characteristics in opposite directions perpendicular to a main extension plane of the structure of fiber material.

According to a further embodiment, the method comprises the step of cutting the first fiber web to substantially the same penetration depth along the complete length of the fold indication. It may be achieved in that the sharp object is formed by a knife blade arranged on a rotating roll, wherein the knife blade is designed so that a tip of the knife blade extends in parallel to an axis of rotation of the rotating roll.

According to a further embodiment, each fold indication in the first fiber web is created by cutting the first fiber web to a penetration depth of 50%-90% of a thickness of the first fiber web and especially to a penetration depth of 60%-80% of a thickness of the first fiber web.

According to a further embodiment, the first fiber web is fed so that it at least partly runs free between the creation of the series of fold indications in the first fiber web, and the folding of the first fiber web at the fold indications. Thus, the first fiber web is in this case at least partly running free in the air. In this way, the first fiber web has some freedom in movement between the folding indication creating device and the folding device. It creates conditions for a lower stress on the material during folding and is especially desired for larger dimensions of the first fiber web, for example for a thickness of the first fiber web of between 0, 5-2,0 mm and specifically between 0, 8-1,0 mm and when the first fiber web is folded to a transverse dimension of 14-25 mm and specifically 18-22 mm.

A further objective of the invention is to provide a machine, which creates conditions for a high pace of manufacturing a structure of fiber material while still achieving a strong construction of the fiber structure.

The objective is achieved by a machine according to claim 13. Thus, it is achieved by a machine for manufacturing a structure of fiber material, wherein the machine comprises: an arrangement for feeding a first sheet of fiber material along a processing path, a device for creating a series of fold indications in the first fiber web, and a device for folding the first fiber web at the fold indications forming a folded configuration and wherein the folding device is arranged downstream of the fold indication creation device in the processing path. According to one aspect, the feeding arrangement comprises a plurality of guiding rolls and driving rolls, which are adapted for rotation, for guiding the first fiber web along the processing path.

According to one aspect, the device for folding the first fiber web at the fold indications is arranged at a distance downstream of the device for creating a series of fold indications in the first fiber web. More specifically, the machine is arranged so that the first fiber web at least partly runs free between the folding indication creating device and the folding device.

According to one embodiment, the fold indication creation device comprises a first roller, which is adapted for rotation, and at least one first sharp object, which is arranged for creating depressions in the first fiber web from a first side of the first fiber web when the first fiber web is fed past the roller, which depressions form a first set of the fold indications. According to one aspect, the sharp object may be formed by a knife.

According to a further embodiment, the first roller is provided with the at least one first sharp object projecting radially from a cylindrical surface of the first roller at its periphery. According to one aspect, the first sharp object is elongated and has a main extension in parallel with an axis of rotation of the first roller. For example, the first sharp object may be arranged so that it projects a distance, which is less than a thickness of the first fiber web. According to one aspect, the sharp object projects the same distance from the cylindrical surface of the roller along the complete length of the first sharp object. According to a further aspect, the first sharp object extends along substantially the complete length of the roller in the direction of the axis of rotation.

According to one alternative, the sharp object may be discontinuous in its extension direction so that at least two different sections of the sharp object projects different distances in the radial direction of the roller. In the last-mentioned case, a first set of sections may be adapted to penetrate the thickness of the first fiber web completely, while a second set of sections may be adapted to penetrate only a portion of the thickness of the first fiber web. The first and second sections may be arranged in an alternating manner in the extension direction of the sharp object. According to a further aspect, the first roller is provided with a plurality of sharp objects, which are arranged spaced in a circumferential direction of the first roller. More specifically, the sharp objects may be arranged at equal spacings in the circumferential direction of the first roller.

According to an alternative to the last-mentioned embodiment, the at least one first sharp object is arranged at distance from a cylindrical surface of the first roller. According to one aspect, the at least one first sharp object is arranged so that a cutting edge of the sharp object is so close to the cylindrical surface of the first roller that it cuts a continuous fold indication when the first fiber web is fed past the first roller. The at least one first sharp object may be arranged stationary.

According to one embodiment, the fold indication creation device comprises a second roller, which is adapted for guiding the first fiber web, wherein the fold indication creation device comprises at least one second sharp object, which is arranged for creating depressions in the first fiber web from a second side opposite the first side when the first fiber web is fed past the second roller, which depressions form a second set of the fold indications. The second roller may be arranged downstream of the first roller in the processing path.

According to one embodiment, the second roller is adapted for rotation and provided with the at least one second sharp object projecting radially from a cylindrical surface of the roller at its periphery. The at least one second sharp object may be arranged stationary.

According to one embodiment, the first roller is mounted for rotation about a first axis of rotation and the second roller is mounted for rotation about a second axis of rotation, wherein the rollers are arranged so that the second axis of rotation is in parallel with the first axis of rotation and so that a gap is formed between adjacent cylindrical surfaces of the rollers, wherein the first fiber web may be fed through the gap.

According to one aspect, the first roller and the second roller are arranged at such a distance relative to one another that the height of the gap substantially matches a thickness of the first fiber web. Further, the sharp object is arranged to project a distance from a cylindrical surface of its respective roller that is the same or smaller than the height of the gap. According to a further development of the last-mentioned embodiment, the first roller and the second roller are rotationally arranged in such a way relative to one another that the at least one first sharp object of the first roller is indexed in relation to the at least one second sharp object of the second roller so that the sharp objects engage with the first fiber web in an alternating manner during feeding of the first fiber web through the gap. Thus, the first sharp object of the first roller will not meet the second sharp object of the second roller during rotation of the rollers. According to a further aspect, the second roller is provided with a plurality of second sharp objects, which are arranged spaced in a circumferential direction of the second roller. More specifically, the second sharp objects may be arranged at equal spacings in the circumferential direction of the second roller. In this way, a regular pattern of fold indications may be achieved on each side of the first fiber web, which creates conditions for achieving any desired zigzag pattern.

According to a further development of the last-mentioned embodiment, the first roller and the second roller are rotationally arranged in such a way relative to one another that said one sharp object of the first roller and said one sharp object of the second roller engage with the first fiber web simultaneously during a period of time when feeding the first fiber web through the gap. Thus, there is always one sharp object in engagement with the first fiber web during feeding of the first fiber web between the two rollers. It creates conditions for a secure feeding of the first fiber web. According to one embodiment, the at least one second sharp object is arranged at distance from a cylindrical surface of the second roller.

According to one embodiment, the fold indication creation device comprises a plurality of first sharp objects, which are arranged in a spaced relationship in an axial direction of the first roller, and a plurality of second sharp objects, which are arranged in a spaced relationship in an axial direction of the second roller.

According to a further embodiment, the machine comprises a first reel, on which the first fiber web is wound up, and wherein the arrangement for feeding the first fiber web along the processing path is adapted to feed the first fiber web from the first reel in a continuous manner. According to a further embodiment, the folding device is adapted to form the first fiber web in a zigzag pattern, wherein the zigzag pattern comprises a series of planar sheet segments and wherein two adjacent sheet segments in the series are connected via a sharp angle at one of the fold indications.

According to a further embodiment, the folding device comprises a first roller, which is adapted for rotation, wherein the roller comprises a toothed structure around its periphery and wherein the toothed structure is adapted to effect the first fiber web so that it is folded at a first set of the fold indications.

According to one aspect, the toothed structure has a regular pattern of teeth in the circumferential direction of the roller. Further, the first roller may be adapted so that a point of each teeth is adapted to effect one of said fold indications in a way folding the first fiber web at the fold indication.

According to a further embodiment, the first toothed roller is mounted for rotation about a first axis of rotation, wherein the folding device comprises a second roller that is mounted for rotation about a second axis of rotation, wherein the rollers are arranged such that the first axis of rotation is in parallel with the second axis of rotation, wherein the second roller comprises a toothed structure around its periphery, wherein the rollers are positioned so that the teeth of the toothed structure of the first roller intermeshes with recesses between the teeth of the toothed structure of the second roller during a synchronized rotation of the first roller and the second roller in a way that the first fiber web may be folded when fed between the first roller and the second roller by being alternately contacted from opposite sides by the teeth of the first roller and the second roller.

According to one aspect, the rollers are positioned so that also the teeth of the toothed structure of the second roller intermeshes with recesses between the teeth of the toothed structure of the first roller during a synchronized rotation of the first roller and the second roller.

According to a further embodiment, at least one tooth of the toothed structure of the first roller and/or the second roller has a continuously tapering shape from a base of the tooth to a free end of the tooth. By such a design of the teeth, an accurate contact of a specific tooth with the first fiber web at the position of a fold indication may be achieved, which creates conditions for an accurate folding.

According to a further embodiment, the tooth has such a shape that the free end is displaced in a circumferential direction of the roller in relation to a midpoint of the base of the tooth. It creates further conditions for an accurate folding.

According to one aspect, the device for folding the first fiber web at the fold indications is arranged at a distance downstream of the device for creating a series of fold indications in the first fiber web, the fold indication creation device comprises two rollers where the first fiber web is fed in a nip between the rollers and the folding device comprises two rollers where the first fiber web is fed in a nip between the rollers. A peripheral speed of the rollers of the folding device may then need to be lower than a peripheral speed of the rollers of the fold indication creation device in order for the folding to a zigzag pattern to take place.

According to an alternative embodiment, the folding device comprises at least one guide member, which defines a guide structure for the first fiber web, wherein the guide structure has a tapered shape in a transverse direction of the processing path and an enlarged shape in a height direction of the processing path so that the first fiber web may be folded during passage of the at least one guide member.

According to a further development of the last-mentioned alternative embodiment, the at least one guide member comprises a plurality of first guide elements, which are arranged in a spaced relationship in the transverse direction of the processing path and adapted to effect the first fiber web so that it is folded at a first set of the fold indications.

According to a further embodiment, the machine comprises an arrangement for feeding a second sheet of fiber material to a position where it meets with the first fiber web downstream of the folding device in the processing path of the first fiber web, and a device for adhering outer portions of a first set of folds of the first fiber web to a surface of the second fiber web.

According to a further embodiment, the machine comprises an arrangement for maintaining the first fiber web in contact with the first roller in the folding arrangement from the formation of the folding configuration to the position where the first fiber web and the second fiber web meet.

According to one aspect, such an arrangement comprises a stationary member arranged in a vicinity of the first roller. More specifically, the stationary member may have an external surface facing the first roller, which has a concave and rounded shape and is positioned at a distance from the periphery of the toothed structure of the first roller. Especially, the stationary member may be positioned at a distance from the periphery of the toothed structure of the first roller substantially matching a thickness of the first fiber web so that the external portions of the first fiber web at the fold indications are supported by the stationary member. Further, the stationary member may comprise at least one metal sheet. According to one alternative, the stationary member may comprise a plurality of parallel metal sheets of the same shape, which are spaced in the direction of the axis of rotation of the first roller.

According to a further embodiment, the machine comprises a device for applying an adhesive on one of the first fiber web and the second fiber web and wherein the adhesive applying device is positioned upstream of the device for adhering the first fiber web to the second fiber web in the processing path.

According to one aspect, the adhesive may be a glue. Further, according to one aspect, the adhesive applying device may comprise a slot for delivery of the adhesive. More specifically, the slot for delivery of the adhesive preferably extends a distance covering a complete width of the first fiber web in its transverse direction. Further, the adhesive applying device may extend along substantially the complete length of the first roller in the axis of rotation.

According to a further embodiment, the adhering device comprises a guide roller that is mounted for rotation about an axis of rotation, wherein the axis of rotation of the guide roller is in parallel with the first axis of rotation of the first toothed roller, wherein the guide roller is adapted to feed the second fiber web to the meeting position with the first fiber web, wherein the guide roller and the first toothed roller are positioned so that a gap is formed between a cylindrical peripheral surface of the guide roller and the free ends of the teeth of the first roller for pushing the fold indications of the first fiber web towards a surface of the second fiber web when the first fiber web is fed past the rollers via the gap. According to a further embodiment, the machine comprises an arrangement for feeding a third sheet of fiber material to a position where it meets with the first fiber web downstream of the position where the second fiber web meets with the first fiber web in the processing path of the first fiber web, and a device for adhering outer portions of a second set of folds of the first fiber web to a surface of the third fiber web.

According to a further embodiment, the device for creating a series of fold in the first fiber web comprises a sharp object and a counter force means facing a tip of the sharp object at a close distance from the tip of the sharp object for acting on the first sheet of fiber material on an opposite side relative to the sharp object thereby forming a counter force acting against the first sheet of fiber material when the sharp object cuts into the first sheet of fiber material from an opposite side, wherein the counter force means is provided with a hard surface where the tip of the sharp object face the counter force means.

The term ’’hard” means that the surface is non-resilient. The surface material of the counter force means may be formed at least partly by a steel, such as a tool steel, for achieving the hard surface. The steel surface may be a hardened surface, ie it has been subjected to hardening during production for achieving the hardness. It provides good conditions for cutting into the first fiber web of a material thickness in the interval 0,5 - 2,0 mm to a large extent.

According to one example, the counter force means is formed by the first and/or second roller at the cylindrically spaced positions where the tips of the respective sharp objects face the roller. Thus, in this case, the hard surface is cylindrical. More specifically, according to one example, an outer surface of the respective roller, comprising the hard surfaces, is circular in cross section.

According to a further embodiment, the device for creating a series of fold indications in the first fiber web comprises a first sharp object and a first counter force means facing a tip of the first sharp object for creating a fold indication from a first side surface of the first sheet of fiber material and a second sharp object and a second counter force means facing a tip of the second sharp object for creating a fold indication from a second side surface of the first sheet of fiber material.

According to a further development of the last-mentioned embodiment, a distance between the first sharp object and the first counter force means is substantially the same as a distance between the second sharp object and the second counter force means for cutting the first fiber web to substantially the same penetration depth from both directions.

According to a further embodiment, the first and/or second sharp object is adapted to create a continuous depression in the first fiber web along the complete length of the fold indication.

According to a further embodiment, the hard surface is convex in a region facing the first and/or second sharp object. It provides good conditions for cutting into the first fiber web of a material thickness in the interval 0,5 - 2,0 mm to a large extent.

By means of a method according to some of the abovementioned embodiments and aspects, a hollow fiber structure is formed, wherein the first fiber web in the folded configuration forms a distance material between the second fiber web and the third fiber web. By proper dimensioning of the fiber webs and selection of material, the hollow fiber structure may be a self-supporting structure. More specifically, the hollow fiber structure may form a load-bearing structural component. Such a structural component creates conditions for forming a package, such as a box-shaped package, for housing goods, such as furniture, such as bookshelves, shelves, doors, tables etc. during transport and storage. Since such a structural component is load-bearing, the goods contained in a package may be free from load-bearing. Further, the load-bearing characteristic creates conditions several such packages may be placed on top of each other during transport and storage.

According to a further aspect of the invention, it comprises a method for forming a box shaped package, comprising the step of folding the fiber structure resulting from the manufacturing method according to anyone of the embodiments and aspects mentioned above in a way that two portions of the fiber structure on opposite sides of a folding line forms two walls of the box-shaped package. According to one aspect of the method, the two portions of the fiber structure are folded relative to one another so that they extend perpendicularly relative to one another. By performing such folding of the fiber structure at three folding lines spaced in the longitudinal direction of the fiber web, four walls of the box-shaped package may be formed from a single fiber structure. Thus, the box-shaped package may be formed with a rectangular shape in a cross section perpendicular to the planes of the walls. According to one example, the folding line extend perpendicular to the longitudinal direction of the fiber structure.

According to one aspect of the method, a folding indication is cut in the fiber structure for forming the folding line for facilitating the folding operation.

Further, a fifth and a sixth wall of the box-shaped package may be cut from the fiber structure and attached on opposite ends of the four walls so that the box-shaped package is closed. According to an alternative, one or both of the fifth and a sixth wall may be formed in another way and may have a different design than the four walls.

According to one aspect of the method for forming a box-shaped package, the hollow fiber structure mentioned above is used. In the hollow fiber structure, the first fiber web forms a distance material between the second fiber web and the third fiber web. According to one aspect of the method for forming a box-shaped package, prior to the folding, portions of the first fiber web, the second fiber web and/or the third fiber web may be removed at a desired position of the respective folding line for creating space for the folding. More specifically, the fiber web, which is desired to form an outer surface of the box-shaped package is remained, while portions of the intermediate fiber web and the fiber web forming an inner surface of the box-shaped package are removed.

Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

In the drawings:

Fig. 1 is a perspective view of a machine according to a first embodiment,

Fig. 2a is an enlarged and partly cut side view of a device for creating fold indications of the machine according to the first embodiment, Fig. 2b an enlarged cross section of a first fiber web downstream of the fold indication creation device in figure 2a,

Fig. 3a is an enlarged and partly cut side view of a device for folding the first fiber web at the fold indications created by the fold indication creation device,

Fig. 3b is an enlarged cross section view of the first fiber web at a fold indication in the folding device according to figure 3a,

Fig. 3c is an enlarged side view of a tooth of a toothed structure of a roll of the folding device according to figure 3a,

Fig. 4 is an enlarged cross section view of the first fiber web in a position downstream of a position where a second fiber web is adhered to the first fiber web,

Fig. 5 is an enlarged cross section view of the first fiber web in a position downstream of a position where a third fiber web is adhered to the first fiber web,

Fig. 6a is perspective view of a box-shaped package formed by planar sheet shaped fiber structures according to figure 5,

Fig. 6b is an enlarged perspective view of a section of the box-shaped package according to figure 6a,

Fig. 6c-f discloses the fiber structure according to the embodiment in figure 5 in consecutive steps for forming walls of box-shaped package according to figure 6a,

Fig. 7 is a cross section view of a first alternative embodiment of a first fiber web with a second fiber web adhered thereto similar to figure 4,

Fig. 8a is a cross section view of a hollow fiber structure of the alternative embodiment according to figure 7 with a third fiber web adhered thereto similar to the hollow fiber structure in figure 5, Fig. 8b-d discloses the fiber structure according to the embodiment in figure 8a in consecutive steps for forming walls of a package,

Fig. 9 is a cross section view of a second alternative embodiment of a hollow fiber structure similar to figure 5,

Fig. 10a is an enlarged perspective cut view of a roller of the device for creating fold indications of the machine according to the first embodiment,

Fig. 10b is an enlarged perspective view of a sharp object arranged at a cylindrical surface of the roller in fig. 10a,

Fig. 11 is a perspective view of a machine according to a second embodiment,

Fig. 12 is an enlarged perspective view of a device for creating fold indications in the machine according to the second embodiment,

Fig. 13a is an enlarged and partly cut perspective view of a device for folding the first fiber web at the fold indications created by the fold indication creation device in the machine according to the second embodiment,

Fig. 13b is an enlarged and partly cut perspective view of a device for maintaining the folded first fiber web in the folded configuration downstream of the folding device according to figure 13a,

Fig. 14 is a cross sectional view of an end portion of the first fiber web in a transverse direction thereof according to an alternative embodiment.

Fig. 15 is a flow chart illustrating a method for manufacturing a structure of fiber material according to one embodiment, and

Fig. 16 is a schematic drawing illustrating a computer readable medium according to one embodiment. DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Fig. 1 is a perspective view of a machine 2 according to a first embodiment. The machine 2 comprises an arrangement 4 for feeding a first web 6 of fiber material along a processing path 8. The fiber material is a material made from cellulose fiber, such as wood pulp. The fiber material may preferably be produced from recycled material. Further, the first web of fiber material has such an internal structure and thickness that it is relatively rigid and prone to partially crack rather than smoothly curve when subjected to bending. The first web of fiber material may have a thickness in the interval 0,5 - 2,0 mm, especially above 0,6 mm, preferably less than 1,5 mm and more preferably less than 1,2 mm. According to one example, the first web of fiber material has a thickness in the interval 0,7 - 1,0 mm.

The machine 2 comprises a first reel 3, on which the first fiber web 6 is wound up, and wherein the arrangement 4 for feeding the first fiber web along the processing path is adapted to feed the first fiber web 6 from the first reel 3 in a continuous manner. The feeding arrangement 4 comprises a plurality of guiding rolls and driving rolls 4a, 4b, 4c, 4d which are adapted for rotation, for guiding the first fiber web 6 along the processing path 8.

The machine 2 further comprises a device 10 for creating a series of fold indications 12 in the first fiber web 6 so that the fold indications 12 are spaced from each other in a longitudinal direction of the first fiber web 6 and extend in a transverse direction relative to the longitudinal direction of the first fiber web 6. More specifically, the fold indications 12 extend perpendicular relative to the longitudinal direction of the first fiber web 6.

The machine 2 further comprises a device 14 for folding the first fiber web 6 at the fold indications 12 forming a folded configuration and wherein the folding device 14 is arranged downstream of the fold indication creation device 10 in the processing path 8.

The fold indication creation device 10 comprises a first roller 16, which is adapted for rotation. The first roller 16 is provided with a plurality of circumferentially spaced first sharp objects 18 projecting radially from a cylindrical surface 20, see figure 2a, 10a and 10b, of the roller 16 at its periphery. The first sharp objects 18 are elongated and arranged at equal spacings in the circumferential direction of the first roller 16. The first sharp objects 18 are adapted for creating depressions in the first fiber web 6 from a first side of the first fiber web when the first fiber web is fed past the roller, which depressions form a first set 12a of the fold indications, see figure 2b. According to one aspect, the first sharp objects 18 may be formed by knives. The first roller 16 is mounted for rotation about a first axis of rotation and each one of the knives extends in parallel with the axis of rotation.

The fold indication creation device 10 further comprises a second roller 22 that is mounted for rotation about a second axis of rotation, wherein the rollers 18, 22 are arranged so that the second axis of rotation is in parallel with the first axis of rotation and so that a gap is formed between adjacent cylindrical surfaces of the rollers. An external cylindrical surface 26 of the second roller 22 forms a support for the first fiber web 6 during penetration via one of the first sharp objects 18 of the first roller 16.

The second roller 22 is provided with a plurality of circumferentially spaced second sharp objects 24 projecting radially from the cylindrical surface 26 of the roller at its periphery. The second sharp objects 24 are elongated and arranged at equal spacings in the circumferential direction of the second roller 22. The second sharp objects 24 are arranged for creating depressions in the first fiber web 6 from a second side opposite the first side during feeding of the first fiber web 6 through the gap, which depressions form a second set 12b of the fold indications, see figure 2b. The external cylindrical surface 20 of the first roller 16 forms a support for the first fiber web 6 during penetration via one of the second sharp objects 24 of the second roller 22. According to one aspect, the second sharp objects 24 may be formed by knives. Each one of the knives 24 extends in parallel with the second axis of rotation.

The first roller 16 and the second roller 22 are arranged at such a distance relative to one another that the height of the gap substantially matches a thickness of the first fiber web 6. Further, the sharp objects 18, 22 are arranged to project a distance from a cylindrical surface of its respective roller that is the same or smaller than the height of the gap.

According to the first embodiment, the first roller 16 and the second roller 22 are identical.

Fig. 2b is an enlarged cross section view of the first fiber web 6 downstream of the fold indication creation device 10 in figure 2a. The first roller 18 and the second roller 22 are rotationally arranged in such a way relative to one another that the at least one first sharp object 18 of the first roller 16 is indexed in relation to the at least one second sharp object 24 of the second roller 22 so that the sharp objects 18, 24 engage with the first fiber web in an alternating manner during feeding of the first fiber web through the gap.

More specifically, every second fold indication 12a is formed in a first surface 13 of the first fiber web 6 and every second fold indication 12b is formed in a second surface 15 of the first fiber web 6, which second surface 15 faces in an opposite direction relative to the first surface 13. The fold indications 12a in the first surface 13 are regularly spaced in the longitudinal direction of the first fiber web 6. Likewise, the fold indications 12b in the second surface 15 are regularly spaced in the longitudinal direction of the first fiber web 6. Further, the spacing between the fold indications 12a in the first surface 13 have equal spacings in the longitudinal direction of the first fiber web. Likewise, the fold indications 12b in the second surface 15 have equal spacings in the longitudinal direction of the first fiber web.

More specifically, the first roller 16 and the second roller 22 are rotationally arranged in such a way relative to one another that the fold indications 12a in the first surface 13 are offset relative to the fold indications 12b in the second surface 15 in the longitudinal direction of the first fiber web so that two adjacent sheet segments 30a, 28b on opposite sides of a fold indication 12b are of different lengths in the longitudinal direction of the first fiber web 6. In other words, a distance a between one of the second fold indications 12b and an adjacent first fold indication 12a in the longitudinal direction of the first fiber web 6 is longer in one direction than a distance b between said second fold indication 12b and an adjacent first fold indication 12a in the longitudinal direction of the first fiber web 6 in the opposite direction. Turning now to figure 4. In this way, the first fiber web 6 may be formed in a zigzag pattern comprising a plurality of longitudinally spaced first sheet segments 28a, 28b with an extension perpendicular to the longitudinal direction of the first fiber web 6 and a plurality of longitudinally spaced second sheet segments 30a, 30b with an extension inclined to the longitudinal direction of the first fiber web 6, wherein every second sheet segment in the longitudinal direction is a first sheet segment 28a, 28b.

Turning now to figure 1 and figures 3a, 3b and 3c. The folding device 14 comprises a first roller 32, which is adapted for rotation, wherein the roller comprises a toothed structure 34 around its periphery. The first toothed roller 32 is mounted for rotation about a first axis of rotation. The toothed structure 34 is adapted to effect the first fiber web 6 so that it is folded at the second set of the fold indications 12b. The toothed structure 34 comprises a plurality of circumferentially spaced teeth 36, wherein during rotation, each teeth is adapted to push the first fiber web 6 at one of said second fold indications 12b from an opposite side of the first fiber web 6 relative to the position of the second fold indication 12b.

The folding device 14 further comprises a second roller 38 that is mounted for rotation about a second axis of rotation, wherein the rollers 32, 38 are arranged such that the first axis of rotation is in parallel with the second axis of rotation. The second roller 38 comprises a toothed structure 40 around its periphery. The toothed structure 40 comprises a plurality of circumferentially spaced teeth 42, wherein during rotation, each teeth is adapted to push the first fiber web 6 at one of said first fold indications 12a from an opposite side of the first fiber web 6 relative to the position of the first fold indication 12a. The rollers 32, 38 are positioned so that the teeth 36 of the toothed structure of the first roller 32 intermeshes with recesses 44 between the teeth 42 of the toothed structure 40 of the second roller 38 during a synchronized rotation of the first roller 32 and the second roller 38 in a way that the first fiber web 6 may be folded when fed between the first roller 32 and the second roller 38 by being alternately contacted from opposite sides by the teeth 36, 42 of the first roller and the second roller.

According to the first embodiment, the first roller 32 and the second roller 38 are identical.

The feeding arrangement 4 comprises a set of driving rolls 4c, 4d which are arranged between the folding indication creation device 10 and the folding device 14 and adapted for pushing the first fiber web 6 in its longitudinal direction towards the gap between the toothed rollers 32, 38. In this way, the first fiber web is already bent somewhat at the fold indication before it is pushed by a tooth.

Turning now to figure 3c, the teeth 36, 42 of the toothed structure 34, 40 of the first roller 32 and the second roller 38 has a continuously tapering shape from a base 44 of the tooth to a free end 46 of the tooth. A first external surface 48 of the tooth 42 extending between a recess between two teeth and the free end is substantially planar while a second external surface 50 extending between a recess on the opposite side of the tooth 46 and the free end has a concave shape. More specifically, the tooth 46 has such a shape that the free end 46 is displaced in a circumferential direction of the roller in relation to a midpoint of the base of the tooth. In figure 3c, an extension of the base of the tooth 46 in the circumferential direction of the roller is defined as the distance X, wherein the midpoint of the base of the tooth is defined as the distance X2 from the adjacent recess and wherein the free end 46 of the tooth is defined as the distance X1 from the adjacent recess.

Turning now to figure 1 again, the machine 2 comprises an arrangement 52 for feeding a second web 54 of fiber material to a position 56 where it meets with the first fiber web 6 downstream of the folding device 14 in the processing path 8 of the first fiber web 6. The second fiber web 54 is planar. The machine 2 comprises a second reel 57, on which the second fiber web 54 is wound up, and the machine is adapted to feed the second fiber web 54 from the second reel 57 in a continuous manner. Further, the machine 2 comprises a device 58 for adhering outer portions of the second set of folds 12b of the first fiber web 6 to a surface of the second fiber web 54.

Further, the machine comprises an arrangement 60 for maintaining the first fiber web 6 in contact with the first roller 32 in the folding arrangement from the formation of the folding configuration to the position 56 where the first fiber web 6 and the second fiber web 54 meet. Thus, the machine 2 provides for maintaining the first fiber web 6 in its folded configuration in the toothed structure of the first roller 32 until it meets the second fiber web 54. The second fiber web 54 is then adhesively connected to the first fiber web 6, wherein any spring back effect in the first fiber web is inhibited.

The arrangement 60 comprises a plurality of axially spaced stationary members 62 arranged in a vicinity of the first roller 32. The stationary member 62 has an external surface facing the first roller, which has a concave and rounded shape and is positioned at a distance from the periphery of the toothed structure of the first roller 32. The stationary member 62 may be positioned at a distance from the periphery of the toothed structure of the first roller 32 substantially matching a thickness of the first fiber web 6 so that the external portions of the first fiber web at the fold indications are supported by the stationary member 62. More specifically, the stationary member 62 comprises a metal sheet. More specifically, a plurality of parallel metal sheets of the same shape are arranged in a spaced relationsip in the direction of the axis of rotation of the first roller 32.

Further, the machine comprises a device 64 for applying an adhesive on the first fiber web 6. The adhesive applying device 64 is positioned upstream of the device 58 for adhering the first fiber web to the second fiber web in the processing path. The adhesive applying device 64 comprises a slot with an extension direction in parallel with the axis of rotation of the first toothed roller 32 and facing the first roller 32 for delivery of the adhesive. More specifically, the slot for delivery of the adhesive preferably extends a distance covering a complete width of the first fiber web in its transverse direction. According to one aspect, the adhesive is continuously (or intermittently) delivered, wherein a portion of the first fiber web defining the fold indication may wipe off adhesive from the adhesive applying device 64 when passing the adhesive applying device 64 during rotation of the first toothed roller 32. The wiped off adhesive will then be positioned along the fold indication.

The adhering device 60 comprises a guide roller 66 that is mounted for rotation about an axis of rotation, wherein the axis of rotation of the guide roller 66 is in parallel with the first axis of rotation of the first toothed roller 32. The guide roller 66 is adapted to feed the second fiber web 54 to the meeting position 58 with the first fiber web 6. The guide roller 66 and the first toothed roller 32 are positioned so that a gap is formed between a cylindrical peripheral surface of the guide roller and the free ends of the teeth of the first roller for pushing the fold indications of the first fiber web 6 towards a surface of the second fiber web 54 when the first fiber web is fed past the rollers via the gap.

Further, the machine 2 comprises an arrangement 68 for feeding a third sheet 70 of fiber material to a position 72 where it meets with the first fiber web 6 downstream of the position 56 where the second fiber web 54 meets with the first fiber web 6 in the processing path of the first fiber web. The third fiber web 70 is planar. The machine 2 further comprises a device 74 for adhering outer portions of the first set of folds 12a of the first fiber web 6 to a surface of the third fiber web 70. The machine 2 comprises a third reel 75, on which the third fiber web 70 is wound up, and the machine is adapted to feed the third fiber web 70 from the third reel 75 in a continuous manner.

Further, the machine 2 comprises a device 76 for applying an adhesive on the first fiber web 6. The adhesive applying device 76 is positioned upstream of the device 74 for adhering the first fiber web to the second fiber web in the processing path. The adhesive applying device 76 is arranged for applying adhesive on a side of the first fiber web 6 opposite of the side facing the second fiber web 54. The adhesive applying device 76 is of similar design and works in a similar manner as the adhesive applying device 64 already described above and will for ease of presentation not be described in any further detail here. The adhering device 74 comprises a pair of rollers 78, 80 arranged in parallel with each other and forming a gap inbetween external cylindrical surfaces of the rollers. A first one of the rollers 80 is arranged to guide the third fiber web 70 to the meeting position 72 with the first fiber web 6. The meeting position 72 is defined in said gap between the rollers 78, 80. Further, the rollers are 78,80 are arranged so that the third fiber web 70 is pushed towards the first fiber web 6 during feeding so that the third fiber web 70 is adhered to the first fiber web 6 via the applied adhesive.

Fig. 4 is an enlarged cut view of the first fiber web 6 in a position downstream of a position where the second fiber web 54 is adhered to the first fiber web 6. The first fiber web 6 has a zigzag pattern, wherein the zigzag pattern comprises a series of planar sheet segments 28a, 28b, 30a, 30b and wherein two adjacent sheet segments 28a, 30a in the series are connected via a sharp angle at one of the fold indications 12b. More specifically, the first fiber web 6 comprises a plurality of longitudinally spaced first sheet segments 28a, 28b with an extension perpendicular to the longitudinal direction of the first fiber web 6 and a plurality of longitudinally spaced second sheet segments 30a, 30b with an extension inclined to the longitudinal direction of the first fiber web 6, wherein every second sheet segment in the longitudinal direction is a first sheet segment 28a, 28b. The first sheet segments 28a, 28b have a shorter extension in its extension direction than the second sheet segments 30a, 30b.

It may be noted that an inner surface of the first fiber web 6 is continuous in a transition between two adjacent sheet segments 30a, 28b at a fold indication and wherein an outer surface of the first fiber web is discontinuous in a transition between the two adjacent sheet segments at the fold indication.

Fig. 5 is an enlarged cut view of an elongated fiber structure 80 comprising the first fiber web 6, the second fiber web 54 and the third fiber web 70. More specifically, the fiber structure 80 is shown in a position downstream of the position 72 where the third fiber web 70 is adhered to the first fiber web 6. The first fiber web 6 forms a distancing structure between the second fiber web 54 and the third fiber web 70. The first fiber web 6 has a zigzag pattern comprising the first sheet segments 28a, 28b extending between the second fiber web 54 and the third fiber web 70 perpendicularly relative to a plane defined by the second fiber web 54. The first fiber web 6 further comprising the second sheet segments 30a, 30b extending between the second fiber web 54 and the third fiber web 70 in an angled relationship relative to the plane defined by the second fiber web 54 and more specifically at a sharp angle thereto. More specifically, the second sheet segments 30a, 30b extend at angle in the interval of 20-60 degrees relative to the plane defined by the second fiber web 54 and particularly around 40 degrees. The first sheet segments 28a, 28b and the second sheet segments 30a, 30b are arranged alternating manner in a longitudinal direction of the fiber structure 80.

The fiber structure 80 has good compressive strength properties in a direction perpendicular to its extension plane thanks to the arrangement of the first sheet segments 28a, 28b perpendicular to its extension plane.

Fig. 6a is perspective view of a box-shaped package 82 formed by planar sheet shaped fiber structures 80 according to figure 5. Fig. 6b is an enlarged perspective view of a section of the box-shaped package according to figure 6a.

Fig. 6c-f discloses the fiber structure according to the embodiment in figure 5 in consecutive steps for forming walls of the box-shaped package 82 according to figure 6a. Fig. 6c corresponds to figure 5, wherein a portion 70a of the third fiber web 70 is indicated. The portion 70a of the third fiber web 70 is positioned between the first sheet segments 28a, 28b, which extend perpendicularly relative to the third fiber web 70. A method for forming the box-shaped package comprises the step of removing the portion 70a of the third fiber web 70 and the inclined sheet segment 30a between the first sheet segments 28a, 28b, see figure 6d. In this way, space is created for folding the fiber structure. The method comprises the further step of folding the fiber structure perpendicularly to its longitudinal direction. More specifically, the method comprises the step of folding the fiber structure around a line 54a, which extend perpendicularly relative to the longitudinal direction of the fiber structure. The folding line 54a is positioned where one of the first sheet segments 28b meet with the second fiber web 54. The method comprises the further step of folding the fiber structure so that it forms a corner of 90 degrees at the folding line, see figure 6f. The folding line 54a may be formed by a folding line indication in the form of a cut, as has been described above.

Fig. 7 is a cross section view of a first alternative embodiment of a first fiber web 106 with a second fiber web 154 adhered thereto similar to figure 4. This embodiment differs in that the first fiber web 106 has a regular zigzag pattern. More specifically, the fold indication creation device is adapted to create equally spaced fold indications in the first fiber web 106 in its longitudinal direction. Thus, after folding, all sheet segments 128, 130 are of equal length. The first sheet segments 128 extending in a first angled relationship relative to a plane defined by the second fiber web 154. The first fiber web 106 further comprising the second sheet segments 130 in a second angled relationship relative to the second fiber web 154. More particularly, the first sheet segments 128 extend with an angle of 60 degrees relative to a plane defined by the second fiber web 154. The second sheet segments 130 extend with an angle of 120 degrees relative to the second fiber web 154.

Fig. 8a is a cross section view of a hollow fiber structure 180 of the first alternative embodiment according to figure 7 with a third fiber web 170 adhered thereto forming a hollow fiber structure 180 similar to the hollow fiber structure 80 in figure 5.

Fig. 8b-d discloses the fiber structure according to the embodiment in figure 8a in consecutive steps for forming walls of a package, such as a box-shaped package similar to the one shown in figure 6a.

In fig. 8a, a portion 170a of the third fiber web 170 is indicated. The portion 170a of the third fiber web 70 is positioned between two adjacent sheet segments 106a, 106b of the folded first fiber structure. A method for forming the box-shaped package comprises the step of removing the portion 170a of the third fiber web 170. The method comprises the further step of folding the fiber structure perpendicularly to its longitudinal direction. More specifically, the method comprises the step of folding the fiber structure around a line 154a, which extend perpendicularly relative to the longitudinal direction of the fiber structure. The folding line 154a is positioned where the two sheet segments 106a, 106b meet with the second fiber web 154. The method comprises the further step of folding the fiber structure so that it forms a corner of 90 degrees at the folding line, see figure 8c. The folding line 154a may be formed by a folding line indication in the form of a cut, as has been described above. Fig. 8d shows a final arrangement of the folding structure 180 at the formed corner.

Fig. 9 is a cross section view of a further alternative embodiment of a hollow fiber structure 280 similar to the hollow fiber structure 80 in figure 5. The first sheet segments 228 extending in a first angled relationship relative to a plane defined by the second fiber web 254. The first fiber web 206 further comprising the second sheet segments 230 in a second angled relationship relative to the second fiber web 254. More particularly, the first sheet segments 228 extend perpendicularly relative to a plane defined by the second fiber web 254. The second sheet segments 230 extend in parallel with a plane defined by the second fiber web 154. In a similar way as has been described above for the embodiment in figure 8a, the fold indication creation device is adapted to create equally spaced fold indications in the first fiber web 206 in its longitudinal direction. Thus, after folding, all sheet segments 228, 230 are of equal length.

Fig. 10a is an enlarged perspective cut view of the first roller 16 of the device for creating fold indications of the machine according to the first embodiment, and fig. 10b is an enlarged perspective cut view of an arrangement of the sharp object 18 arranged at the cylindrical surface of the first roller 16 in fig. 10a. The sharp object 18 has an elongated shape extending in parallel with the axis of rotation of the roller 16. Further, the sharp object 18 has the shape of a sheet and has a sharp edge 21 projecting from the cylindrical surface 20. The first roller 16 comprises a plurality of circumferentially spaced channel shaped cavities 23, which are open radially outwards. The sharp object 18 is arranged partly within the cavity 23 and partly projecting outside of the cavity. More specifically, the sharp object 18 is arranged so that a main portion thereof is positioned inside of the cavity and so that the sharp edge 21 projects radially out from the cavity. Further, the sharp object 18 is clamped to its desired position.

The sharp object 18 is arranged in contact with an inner surface 25 delimiting the cavity in the circumferential direction. Further, an elongated support element 27 for holding the sharp object in a desired position is arranged in the cavity 23. The elongated support element 27 has an external surface 39 facing in the circumferential direction for contacting a main side surface the sharp object 18. The elongated support element 27 has a through-hole 29 for receipt of a fastener 31 in the form of a screw. Further, the first roller 16 has a radially extending threaded hole 33 in communication with the cavity 23. Further, the walls defining the through-hole 29 has a step 35 for supporting a head 37 of the screw 31 in an axial direction of the screw. Further, the cavity 23 has a portion 41 extending in the circumferential direction and at a radial distance from the external cylindrical surface 20 of the roller. Further, the elongated support element 27 has a projection matching the position of the cavity portion 41. The sharp object 18 is fastened in its operative position by positioning the screw in the through-hole 29 and screwing the screw 31 in the threads of the hole 33, wherein the elongated support element 27 will be forced against an edge 43 of the cavity portion 41, which in turn will angle the elongated support element 27 somewhat and push the sharp object towards the surface 25.

Fig. 11 is a perspective view of a machine 302 for manufacturing a structure of fiber material according to a second embodiment. The machine 302 comprises an arrangement 304 for feeding a first sheet of fiber material 306 along a processing path 308.

The machine 302 comprises a first reel 303, on which the first fiber web 306 is wound up, and wherein the arrangement 304 for feeding the first fiber web along the processing path is adapted to feed the first fiber web 306 from the first reel 303 in a continuous manner.

The machine 302 further comprises a device 310 for creating a series of fold indications 312, see figure 12, in the first fiber web 306 so that the fold indications 312 extend in a longitudinal direction of the first fiber web 306 and are spaced from each other in a transverse direction relative to the longitudinal direction of the first fiber web 306.

Turning now to figure 12, it shows an enlarged perspective view of the fold indication creation device 310. The fold indication creation device 310 comprises a first roller 316, which is adapted for guiding the first fiber web 306, and a plurality of first sharp objects 318, which are arranged for creating depressions in the first fiber web 306 from a first side of the first fiber web when the first fiber web is fed past the first roller, which depressions form a first set 312a of the fold indications. The plurality of first sharp objects 318 are arranged at a distance from a cylindrical surface 320 of the first roller 316. The plurality of first sharp objects 318 are arranged in a spaced relationship in an axial direction of the first roller 316 in a way that the edges face the cylindrical surface 320 of the first roller 316.

The fold indication creation device 310 comprises a second roller 322, which is adapted for guiding the first fiber web 306, wherein the fold indication creation device 310 comprises a plurality of second sharp objects 324, which are arranged for creating depressions in the first fiber web 306 from a second side opposite the first side when the first fiber web is fed past the second roller 322, which depressions form a second set 312b of the fold indications. The plurality of second sharp objects 318 are arranged at a distance from a cylindrical surface 326 of the second roller 322. The plurality of second sharp objects 324 are arranged in a spaced relationship in an axial direction of the second roller 322 in a way that the edges face the cylindrical surface 326 of the second roller 322.

Turning now again to figure 11. The machine 302 comprises a device 314 for folding the first fiber web 306 at the fold indications 312 forming a folded configuration and wherein the folding device 314 is arranged downstream of the fold indication creation device 310 in the processing path.

The machine 302 further comprises an arrangement 352 for feeding a second web 354 of fiber material to a position 356 where it meets with the first fiber web 306 downstream of the folding device 314 in the processing path 308 of the first fiber web 6. The second fiber web 354 is planar. The machine 302 comprises a second reel 357, on which the second fiber web 354 is wound up, and the machine is adapted to feed the second fiber web 354 from the second reel 357 in a continuous manner. The second reel 357 is arranged so that its axis of rotation is in parallel with the processing path 308 at the meeting position 356. The arrangement 352 comprises a further guide roller 359 for guiding the second fiber web 354. The further guide roller 359 is arranged upstream of the meeting position 356 with regard to the feeding direction of the second fiber web 354. The further guide roller 359 has an axis of rotation directed at about 45 degrees in relation to the processing path 308 at the meeting position 356.

Further, the machine 302 comprises a device 358 for adhering outer portions of the first set of folds 312a of the first fiber web 306 to a surface of the second fiber web 354.

Further, the machine 302 comprises a device 315 for maintaining the first fiber web 306 in the folded configuration during at least a part of the distance between the folding device 314 and the adhering device 358. The device 315 for maintaining the first fiber web 306 in the folded configuration is positioned at a distance from a downstream end of the folding device 314. In this way, the first fiber web has some freedom in movement between the devices 314, 315. The device 315 for maintaining the first fiber web 306 in the folded configuration is adapted to guide the first fiber web so that it is fed in the folded configuration along a straight line towards a downstream adhesive applying device 364.

Further, the machine comprises the device 364 for applying an adhesive on a first surface of the first fiber web 306. The adhesive applying device 364 is positioned upstream of the position 356 where the second fiber web 354 meets with the first fiber web 306 in the processing path for adhering the first fiber web to the second fiber web 354.

The machine 302 further comprises an arrangement 368 for feeding a third web 370 of fiber material to a position 372 where it meets with the first fiber web 306 downstream of the folding device 314 in the processing path 308 of the first fiber web 6. The third fiber web 370 is planar. The machine 302 comprises a third reel 375, on which the thid fiber web 370 is wound up, and the machine is adapted to feed the third fiber web 370 from the third reel 375 in a continuous manner. The third reel 375 is arranged so that its axis of rotation is in parallel with the processing path 308 at the meeting position 372. The arrangement 352 comprises a further guide roller 371 for guiding the thirdd fiber web 370. The further guide roller 371 is arranged upstream of the meeting position 372 with regard to the feeding direction of the third fiber web 370. The further guide roller 371 has an axis of rotation directed at about 45 degrees in relation to the processing path 308 at the meeting position 356.

Further, the machine comprises a device 376 for applying an adhesive on a second surface of the first fiber web 306 opposite the first surface. The adhesive applying device 376 is positioned upstream of the position 372 where the third fiber web 370 meets with the first fiber web 306 in the processing path for adhering the first fiber web to the third fiber web 370.

Further, the machine 302 comprises a device 374 for adhering outer portions of the second set of folds 312b of the first fiber web 306 to a surface of the third fiber web 370.

More specifically, each one of the adhering devices 358, 374 comprises a set of rolls and an endless band running over two of said rolls. Further, the adhering devices 358, 374 are arranged on opposite sides of the processing path 308 of the first fiber web in a way that a fiber structure comprising the first fiber web 306, the second fiber web 354 and the third fiber web 370 is fed through a gap between the adhering devices 358, 374 while being pressed from opposite sides.

Fig. 13a is an enlarged and partly cut perspective view of the folding device 314. The folding device 314 comprises a guide member 332, which defines a guide structure for the first fiber web 306. The guide structure defines a channel for passage of the first fiber web 306. The guide structure has a smaller extension in a transverse direction relative to the processing path 308 at a downstream position in relation its extension in the transverse direction at an upstream position so that the first fiber web 306 may be folded during passage of the at least one guide member 332. More specifically, an inlet of the guide structure has an extension in the transverse direction of at least the same length as a width of the first fiber web 306 in an unfolded state. Further, an outlet of the guide structure has an extension in the transverse direction of the same length as a width of the first fiber web 306 in a desired folded state. More specifically, the guide structure has a continuously reducing transverse extension in a forwards direction of the processing path 308 between the inlet and the outlet. In other words, the guide structure has a tapered shape in a forwards direction of the processing path 308.

Further, the guide structure has a larger extension in a height direction relative to the processing path 308 at a downstream position in relation its extension in the height direction at an upstream position so that the first fiber web 306 may be folded during passage of the at least one guide member 332. More specifically, the inlet of the guide structure has an extension in a height direction of at least the same length as a heigth of the first fiber web 306 in an unfolded state. Further, the outlet of the guide structure has an extension in the height direction of the same length as a heigth of the first fiber web 306 in the desired folded state.

The guide member 332 comprises one guide portion 334, 336 on either side of the processing path 308 in the transverse direction. The guide portions 334, 336 form a tapering space in a forwards direction of the processing path 308 so that the first fiber web 306 folds at the fold indications. The guide member 332 further comprises one guide portion 338, 340 on either side of the processing path 308 in a height direction. The guide portions 338, 340 form an enlarging space in a forwards direction of the processing path 308 supporting the first fiber web 306 to fold at the fold indications.

Further, the guide member 332 comprises a plurality of first guide elements 342, which are arranged in a spaced relationship in the transverse direction of the processing path 308 and adapted to effect the first fiber web 306 so that it is folded at a first set of the fold indications 312a. The first guide elements 342 are elongated and form a plurality of ridges. More specifically, the elongated first guide elements 342 has a cross section shape adapted for the intended cross section shape of one main side of the first fiber web 306. More specifically, the elongated first guide elements 342 has a triangular cross section shape. Similarly, the guide member 332 comprises a plurality of second guide elements 344, which are arranged in a spaced relationship in the transverse direction of the processing path 308 and adapted to effect the first fiber web 306 so that it is folded at a second set of the fold indications 312b. The second guide elements 344 are elongated and form a plurality of ridges. More specifically, the elongated second guide elements 344 has a cross section shape adapted for the intended cross section shape of one main side of the first fiber web 306, which is opposite of the aforementioned main side. More specifically, the elongated second guide elements 344 has a triangular cross section shape.

The first guide elements 342 and the second guide elements 344 are pointing in opposite directions and arranged in a way that a gap is formed between them. The first guide elements 342 and the second guide elements 344 are arranged in a way that every second guide element in the transverse direction of the first fiber web is a first guide element 342 and every second guide element is a second guide element 344. The guide elements 342, 344 are positioned so that the first guide elements 342 intermeshes with recesses between the second guide elements 344 and vice versa.

The gap/space defined by the guide member 332 for receiving the first fiber web 306 during feeding has such a shape in cross section that the first fiber web 306 may be formed to the regular zigzag folded configuration similar to what is shown in figure 8a. It is of course also possible to achieve a folded configuration similar to figure 5 or figure 9 by modifying the arrangement. According to one alternative, the guide structure has a different design than defining a channel with a cross section design matching the cross section of the first fiber web 306 for passage of the first fiber web 306. For example, the guide structure may comprise a plurality of parts defining the boundaries of the processing path 308 in different directions. According to one aspect, the guide structure may comprise a first pair of support plates on opposite sides of the processing path 308 in the transverse direction and a second pair of support plates on opposite sides of the processing path 308 in the height direction.

Fig. 13b is an enlarged and partly cut perspective view of the device 315 for maintaining the folded first fiber web 306 in the folded configuration downstream of the folding device 314. The device 315 for maintaining the folded first fiber web 306 in the folded configuration has similarities with the folding device 314. For ease of presentation, only the main differences will be mentioned here. The folding device 314 comprises a guide member 337, which defines a guide structure for the first fiber web 306. The guide structure defines a channel for passage of the first fiber web 306. The guide structure has the same extension in a transverse direction relative to the processing path 308 at a downstream position in relation its extension in the transverse direction at an upstream position. More specifically, the channel for passage of the first fiber web 306 has the same cross section at an inlet of the device 315 as at an outlet of the device 315. More specifically, the channel for passage of the first fiber web 306 has the same cross section all the way between the inlet and the outlet. More specifically, the channel for passage of the first fiber web 306 has a zigzag shape in cross section. According to an alternative or complement, such a device may comprise two spaced stationary guide members arranged one on either side of the processing path.

Fig. 14 is a cross sectional view of an end portion of the first fiber web 306 in a transverse direction thereof according to an alternative embodiment. A plurality of outermost folds 307 in the transverse direction of the first fiber web 306 are pressed together so that planar sheet segments defined by the folds are substantially in parallel with each other. The pressed together planar sheet segments form an elongated, rigid edge section extending in the longitudinal direction of the web structure. Such a ridge section may be termed a lath. The first fiber web 306 may have a similar edge design at its opposite edge. Two support portions 333, 335 are arranged in a spaced relationship in the transverse direction commensurate with a final desired width of the elongated, rigid edge section for compressing the outermost folds when the first fiber web is fed past this position.

Fig. 15 is a flow chart illustrating a method for manufacturing a structure of fiber material according to one embodiment. The method comprises the steps of: feeding a first web of fiber material along a processing path 400, creating a series of fold indications in the first fiber web 410, folding the first fiber web at the fold indications thereby forming a folded configuration 420, feeding a second web of fiber material to a position where it meets the first fiber web downstream of the folding of the first fiber web in the processing path of the first fiber web 430, adhering outer portions of a first set of folds of the first fiber web to a surface of the second fiber web 440 feeding a third web of fiber material to a position where it meets the first fiber web downstream of the folding of the first fiber web in the processing path of the first fiber web 450, adhering outer portions of a second set of folds of the first fiber web to a surface of the third fiber web, wherein the second set of folds point in an opposite direction relative to the first set of folds 460.

Figure 16 is a schematic drawing illustrating an example computer readable medium according to some embodiments. The computer program product comprises a non- transitory computer readable medium 500 having thereon a computer program 510 comprising program instructions, wherein the computer program being loadable into a data processing unit and configured to cause execution of the method steps of any of the methods described above. The data processing unit may comprise one or more parts, such as controlling circuitry in the form of one or more controllers, one or more processors, or the like.

The described embodiments and their equivalents may be realized in software or hardware or a combination thereof. The embodiments may be performed by general purpose circuitry. Examples of general purpose circuitry include digital signal processors (DSP), central processing units (CPU), co-processor units, field programmable gate arrays (FPGA) and other programmable hardware. Alternatively or additionally, the embodiments may be performed by specialized circuitry, such as application specific integrated circuits (ASIC). The general purpose circuitry and/or the specialized circuitry may, for example, be associated with or comprised in an apparatus.

Embodiments may appear within an electronic apparatus comprising arrangements, circuitry, and/or logic according to any of the embodiments described herein.

According to some embodiments, a computer program product comprises a computer readable medium such as, for example a universal serial bus (USB) memory, a plug-in card, an embedded drive or a read only memory (ROM). Figure 5 illustrates an example computer readable medium in the form of a compact disc (CD) ROM 500. The computer readable medium has stored thereon a computer program comprising program instructions. The computer program is loadable into a control unit, or data processor (PROC) 520, which may, for example, be comprised in an apparatus. When loaded into the data processing unit, the computer program may be stored in a memory (MEM) 530 associated with or comprised in the data-processing unit. According to some embodiments, the computer program may, when loaded into and run by the data processing unit, cause execution of method steps according to, for example, any of the methods described herein.

It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

Although two different embodiments of the machine have been disclosed, features from the first embodiment may be replaced by features of the second embodiment and vice versa. For example, the arrangement for feeding the second fiber web in the second embodiment may be replaced by the arrangement for feeding the second fiber web in the first embodiment, and vice versa. Likewise, the arrangement for feeding the third fiber web in the second embodiment may be replaced by the arrangement for feeding the third fiber web in the first embodiment, and vice versa.

Further, the folding device in the second embodiment is stationary. According to an alternative, the folding device in the second embodiment may comprise movable parts, such as a roller positioned with its axis of rotation perpendicular relative to the processing path and provided with a guiding structure at its cylindrical peripheral surface, which is adapted for folding the first fiber web during rotation when the first fiber web passes the roller.