Most materials used for the production of hygienic goods are still shipped from the suppliers to the end users in rolls. With the development of new, often thicker materials, such as airlaid, as well as the desired increase in production speed, supplying materials in rolls is no longer a cost-effective way of delivery. Thus, an alternative method has been developed, which is delivering materials in festooned blocks. This way of delivery is a great improvement in terms of handling and material management, and cuts down material shipping and warehousing costs considerably, due to its space saving shape, and also reduces the cost of equipment needed to supply the materials to the production line, as well as improves material runnability on high-speed converters.

The general technique of folding material is quite old. US-A 1985676 discloses a method and an apparatus for folding a paper block from a continuous web of paper.

First, paper material is fed to an indenting mechanism providing folding lines in certain intervals. The folded material is received by helicoidal members assisting to obtain correct stacking of the folded sheets of band material. Due to the semi-rigid structure of the paper material and the fact that the material is laid down by gravity,

the folding process is very slow and nearly not practicable for new materials such as airlaid, which is fluffy and light.

Another method for folding material is disclosed in EP 0 366 038 A2. According to this concept, web material is fed between two conveyors on which a block of material is oscillating, so that the block of folded material grows from the bottom to the top. As soon as one block is completed, it is moved to another position and the building of a new block can begin. In this way, the bottom of one block is linked to the top of the next block. This method has the serious drawback that oscillating of a block can be started with high speed in the beginning, but as soon as the block has reached a certain height, the oscillating movement requires to reduce speed.

Accordingly, this method is not applicable for high volume blocks of folded material, as required in the hygienic industry. Another drawback is due to the fact that the weight of the block increases continuously, affecting the pressure exerted on the layer being folded, which leads to lack of stability.

The process is also known from a field of industry where folding cylinders are used for producing napkins and the like. However, in this field of application the axes of the folding cylinders are in a vertical position, and the folded material is accumulated sidewise and withheld by a spring loaded plate. The drawback of using this system for festooning applications of new materials like airlaid comes from the standard width of such rolls and the physical limitations of the system to handle such wide, light and flexible materials in a vertical position.

A new development is shown in EP 0 939 054 A2, disclosing an apparatus for folding a continuous strip of material which usesiá pair of vertically arranged cylinders having means for deviating and gripping the strip for building a block of folded material. Each cylinder has the gripping means arranged on one side and the deviating means on the opposite side. In order to move the strip material from a position between the cylinders to the upper surface of the block, the gripping means clamp the strip material and move it by a rotation of less than 180° to the upper surface of the block of folded material. Although this method is also applicable for

relatively light material, such as airlaid, the finished block will only be of medium quality, and the process speed and the maximum width of the folded material are quite limited. If the cylinders rotate with high speed, the material strips are not accurately laid one on top of the other, and some frictional engagement between the rotating cylinders and the upper surface of the block may lead to damages in the block, in particular if the web material is a nonwoven fabric such as airlaid, which is very delicate to handle. When the seat windows described in this document pass on top of the material surface, the damage will be inevitable. Another limitation of such cylinders comes from the fact that in the advanced airlaid industry, there are often materials with significant variations on each side, so that the friction present between the cylinders and the material is different in every half cycle, resulting in irregular layers. A further serious limitation of this system and of all commercial folding cylinders is due to the use of one single cam to control the opening and closing movements of the gripping means, providing no possibility for adjusting the fold length. It is obvious for a person skilled in the art that this is a significant limitation in terms of the capacity of such systems to process different materials as required by the broad variety of nonwoven materials.

It is an object of the present invention to provide a method and an apparatus for forming a package unit of festooned material which can operate at high speed, which is able to handle the nonwoven material in an optimised process to avoid any damage or deformation, and wherein the layers of folded material are laid one on top of the other with utmost accuracy, with a minimum material stress from the very first layer to the maximum output height.

This object is solved by an apparatus and a method for forming a package unit having the features of claim 1 and 7, respectively.

According to the invention, the apparatus for forming a package unit comprises two folding means being rotatably around a horizontal axis and between which web material is fed from the top, whereby the folding means are provided with gripping means and pushing means acting together for introducing a part of the web material

into the gripping means which are capable of moving said web material alternately to one side or the opposite side of a block of folded material, and means for pressing on the uppermost web layer being arranged on opposite sides of the block to press on one side of the block while web material is laid down on the other side of the block.

Due to the horizontal arrangement of the folding means, it is possible to eliminate limitations in maximum width being handled, as gravity affects the horizontally oriented web material layers equally. In addition, the means for pressing on the uppermost web layer and the gravity effect act together in the same direction, which improves the stability of the folding process and allows operations at high speed.

Compared with linear festooning technology, where a plaiting arm moves back and forth to put down the material layers, and which can hardly be operated reliably beyond 100 linear meters per minute, the newly developed rotary festooning technology has proved to be reliable at average production speeds of about 350 linear meters per minute.

In a preferred embodiment of the invention the pressing means are respectively arranged below the rotating folding means, so that a compact folding device can be provided.

If each pressing means is connected to a respective rotating folding means via an adjustable eccentric mechanism, the folding process can be optimised for web materials with different properties.

Preferably, the opening and the closing point of the gripping means are adjustable so that the festooning process can be adapted to different materials. In particular, the handling of materials with a different thickness can be improved by the adjustment of a cam mechanism, as the opening and the closing point of the gripping means can be set independently from each other. Preferably, the opening of the gripping means is controllable by a first cam, and the closing of the gripping

means is controllable by a second cam, whereby the first and second cam are connected, but nevertheless independently adjustable from each other, thus allowing an adjustment of the folding length.

According to the method for forming a package unit, the web material is fed from the top to a folding device having two folding means rotating around a horizontal axis. Then the web material is guided alternately with each of the rotating folding means, thereby folding the web in a zigzag-like manner building a block of folded material. During the folding process, pressing means act on the uppermost web layer on one side of the block while the web material is layered down on the other side of the block.

Preferably, the degree of pressure on the block is measured and processed to maintain a predetermined degree of pressure during building of the block. In a preferred embodiment of the invention, a certain pressure is exerted on the uppermost web layer during the folding process, and the degree of compression is measured and used as a feedback to assure constant passing of the material, without any tension on the web. If the block is arranged on a movable lifting element, the obtained data can be used for controlling the speed of the vertical movement of the lifting element. Accordingly, if the pressure is too low or too high, there is an immediate automatic adaptation of the speed, so that steady process conditions are assured.

In a preferred embodiment the package unit consists of more than one block which is linked to another block by a continuous web portion in order to build a"mega- block"which is transported as one package unit to the end user.

It is also a preferred embodiment to perforate the web material in longitudinal direction, i. e. parallel to the side edges, before folding it to a block. Thus, smaller strips of the web material can be drawn from the package unit and further processed to make hygienic products or the like without needing to be cut into the required width at the end user's facilities.

The invention will now be described in detail with reference to the appended draw- ings: Fig. 1 shows a schematic drawing of the overall manufacturing method; Fig. 2 shows a schematic side view of a first embodiment of the apparatus ac- cording to the present invention; Fig. 3 shows a schematic side view of the folding cylinders and the gripping means; Fig. 4 shows an enlarged side view of the connecting section of the two folding cylinders; Fig. 5 shows a side view of the two folding cylinders and their linkage for moving the fingers; Fig. 6 shows a top view of the apparatus, and Fig. 7 a perspective view of the double cam system for actuating the gripping means.

After fabrication, a mother roll 1 of airlaid material is delivered to the festooning system. The full width of the mother roll is unwound so that a web 10 is fed to the processing station.

The web 10 is guided through a tension control system comprising two rollers 2 and a pneumatic dancing roller 3 being connected to a potentiometer to feedback the system on the dancing roller position. The tension control system assures process stability, since the quality of the festooning process is indexed to tension steadiness and avoidance of web elongation.

Then the web 10 passes through a web guiding system comprising rollers 4 and 5 and an automatic device tracking the web 10 within narrow tolerances and thus controlling the position of the web in the slitting station.

When the festooner is used for multilane production, the material has to be slit into lanes of the required width. This operation is performed at the slitting station with unique crush cut perforation knives 7 that provide multiple width variation capabilities, depending on machine configuration. The slitters are pneumatically loaded with a constant and uniform slit pressure against an anvil roll 6. The slitting system includes a precise S-wrap material metering system. Trim cut of the product edges is also performed in this station, reducing material waste to a minimum.

In the next station, the web 10 is guided between two rolls 8 having another tension control system 9. The tension control system 9 comprises a lever with a roll pressing against the web 10 to assure constant web tension during the festooning process. Then the web 10 is fed to two folding cylinders 11 and 12 to build a block 50 of folded material.

The block 50 is arranged on a lifting element which is moved downwards during the festooning process. As soon as the required height of the material block 50 is reached, the block 50 is transferred to another position and a new block is built by the festooner system. The finished blocks can be either separated by a web cutting system or packed together as one package unit. Before transportation, the block or package unit is compressed in a compressing station, to reduce its volume.

The folding of the web 10 by the folding cylinders 11 and 12 will now be described in detail with reference to Fig. 2 to 7.

The web 10 of airlaid material is passing with constant web tension through a gap between the right folding cylinder 11 and the left folding cylinder 12. Each folding cylinder 11 and 12 has a gripping means 13 and 16, and a pushing means 14 and 15.

Below the right folding cylinder 11, a swinging set of fingers 17 is mounted on a holder 19. Integrated into the fingers 17 are measuring means 18 for measuring the actual pressure of the fingers 17 on the material block 50 during the festooning process. On the opposite side, a set of fingers 20 mounted to a holder 22 is provided, having another measuring means 21 for measuring the pressure of the fingers 20 on the material block 50.

The folding cylinders 11 and 12 as well as the holders 19 and 22 are mounted to a frame 23. Below the frame 23, a movable lifting element 24 is provided for receiving the block 50 during the festooning process. The lifting element 24 is arranged on a pneumatic system 25 that allows the lifting element 24 to rock while the first block layers are formed in order to maintain a continuous contact between the lifting element 24 and the web 10. The pneumatic system 25 is mounted to a lifting frame 26 being movable together with the lifting element 24.

The transportation of the web 10 by the folding cylinders 11 and 12 will now be described with reference to Fig. 3 and 4.

First of all, this is a cyclical process, where the respective elements of the counter- rotating folding cylinders 11 and 12 are alternating between an operative and a non- operative position. This rotation is indicated by arrows a and ß. With each rotation of the cylinders, two layers of the block 50 are formed. The web 10 is pushed to the gripping means 13 mounted in the folding cylinder 11. The gripping means 13 comprises a gripping element 131 being pivoted around an axis 130. The gripping element 131 is mounted to a holding member 132 being connected with a cam follower 135 contacting a cam 136. On the opposite side of the axis 130 the holding member 132 is provided with a spring 133 biasing the gripping element 131 to a closed position and allowing a predetermined rotation of the gripping element 131 in case of a forceful actuation, for example by the pushing means 15, due to a very thick material.

The pivotable pushing means 15 is mounted to a lever 150 being connected to a spring 151 which is fixed on one side to the lever 150 and on the other side to the folding cylinder 12. If a vertical force acts on the pushing means 15, the pushing means 15 pivots against the biasing pressing force of spring 151 to avoid any damage to the web 10 contacted by the pushing means 15. The lever 150 is held in a middle position by a stopper element (not shown).

In order to clamp the web 10 between the gripping member 131 and a receiving element 134 mounted in the folding cylinder 11, the pushing element 15 tucks a portion of the web 10 between the gripping element 131 and the receiving element 134. The gripping means 13 is cam-driven and opens and closes with respect to the angular position of the folding cylinder 11. Before reaching the position shown in Figure 4, the gripping means 13 has opened to receive a portion of the web 10 and clamp it between the gripping element 131 and the receiving element 134. Then the gripping means 13 closes and the web 10 is transmitted to an angular position of about 120°. In this position the gripping means 13 opens to release the web 10.

Subsequently, the folding cylinder 11 rotates another 60°, so that the pushing means 14 can tuck the web 10 to the gripping element 16. The gripping element 16 grips the web 10 and transmits it to a position approximately 120° further before releasing the web 10. Finally, with a rotation of another 60°, the folding cylinders 11 and 12 move to the original position shown in Fig. 3, and the cycle starts again.

At the same time, the fingers 17 and 20 alternately press on the block 50 of folded material. In the position shown in Fig. 2, the fingers 17 are in a rest position received between ribs 110 integrated in the folding cylinder 11. Between the circumference of the fingers 17 and the circumference of the folding cylinder 11, a small gap 111 is provided with a size sufficient to allow passing of the clamped portion of the web 10 around to the block 50. When the gripping means 13 has moved about 120°, the gripping means 13 opens and releases a clamped portion of the web 10. Then the fingers 17 are pivoted around the holder 19 in order to press on the uppermost layer of web material of the block 50. Thus, the web 10 being moved along the folding cylinder 11 with high speed can be stopped abruptly in

order to lay down each layer of web material in an accurate position. As soon as the fingers 17 are pressing on the block 50, a new portion of web material 10 is fed between the folding cylinders 11 and 12 until the pushing means 14 press a portion of the web 10 to the gripping means 16 of the folding cylinder 12. Subsequently, the folding cylinder 12 rotates with the gripped portion of the web 10 around the fingers 20, which are then in a rest position while the fingers 17 are pressing on the block 50. When the gripping means 13 releases the web 10, the fingers 20 are pressing on the block 50, while the fingers 17 are moved to a rest position.

As to be seen in Fig. 5, the movement of the fingers 17 and 20 is driven by an eccentric system. The holder 19 is mounted to frame 23, whereby a connecting element 43 with a receiving bore 42 surrounds a pin 41 of a linking device 40. The linking device 40 is connected to a rotating disk of the folding cylinder 11 at an eccentric fixing point 39 in order to provide the swinging movement of the fingers 17. By analogy, the fingers 20 are attached to a connecting element 34 having a receiving bore 35 in which a pin 36 of a linking device 37 is provided. The linking device 37 is connected to an eccentric fixing point 38 of a rotating disk mounted to the folding cylinder 12. Thus, depending on the position of the folding cylinders 11 and 12, the fingers 17 and 20 are alternately oscillating between a rest portion in the folding cylinders 11 and 12 and a pressing position below and out of the cylinders 11 and 12, respectively.

As shown in Fig. 6, the folding cylinders 11 and 12 are driven by a motor 27 and provided with gears 28 and 29. Both folding cylinders 11 and 12 are connected by split toothed wheels 30 and 31, whereby the distance can be adjusted in order to handle web materials of different thicknesses.

In Fig. 7 the adjustable cam mechanism for opening and closing the gripping means 14 is shown. On one side of the folding cylinder 11 the cam 136 is mounted to the rotational axis of the folding cylinder 11 formed by a shaft 100. The cam 136 is contacting the cam follower 135 being mounted to holding member 132 which is rotatably around an axis 130. The axis 130 extends over the whole length of the

folding cylinder 11. The gripping means 13 are fixed in the middle portion of the axis 130 by clamping means of the gripping elements 131. The clamping means can be formed by known screw connections or other suitable connecting elements.

Accordingly, it is possible to adjust the position of the gripping elements 131 on the axis 130. On the opposite side another cam 138 is mounted to the shaft 100. The cam 138 is contacting a cam follower 137 mounted to a holding member 139. The holding member 139 is connected to the axis 130, so that a movement of the cam follower 137 results in a rotation of axis 130 and a movement of the cam follower 135.

Both cams 136 and 138 have a similar shape and a section with a bigger radius and a section with a smaller radius. Between these two sections, ramps 140,141 and 142 are provided so that the cam followers 135 and 137 are smoothly moved in a radial direction during the rotation of the folding cylinder 11.

The cam 136 acts to open the gripping means 13 by moving the cam follower 135 to a radial outward position by ramp 140 during rotation of the cam 136 in direction.

This movement results in a rotation of axis 130 and the connected gripping elements 131 against the biasing force of pressure springs 133 mounted to the holding member 132. In addition, the holding member 139 is rotated so that the cam follower 137 gets out of contact with cam 138. Then the cam follower 135 slides on cam 136 and the gripping elements 131 rest in the open position. After a short rotation angle, the cam follower 137 gets in contact with the cam 138 due to another ramp provided on cam 138. The open position of the gripping elements 131 can be maintained in a range of approximately 240°, i. e. from the position when the material has been layered down to the position when the pushing means 15 are tucking material to the gripping means 13.

Before the gripping elements 131 are moved to the closed position the cam follower 135 gets out of contact with the cam 136 due to a ramp 142. Then the cam follower 137 holds the gripping elements 131 in the open position against the biasing force of the springs 133. After another small angle of rotation the cam follower 137 slides

on ramp 141 to a radial more inward position, so that the axis 130 rotates and the gripping elements 131 are moved to a closed position under the force of springs 133. In the closed position the web 10 is gripped and transported to the upper side of block 50. As soon as the web 10 is to be released, the cam follower 135 slides on ramp 140 and the gripping elements 131 are opened again.

In order to adjust the opening and closing position of the gripping elements 131, the cams 136 and 138 are fixed in a predetermined rotary position. The angle of the opening position can be adjusted independently of the closing position, since the cams 136 and 138 are fixed separately to the shaft 100. Preferably the cams 136 and 138 are provided with markings to facilitate the adjustment of their rotational position with respect to the folding cylinders 11 and 12, respectively.

Although only the double cam mechanism for the right folding cylinder 11 has been described, the same double cam mechanism is included in the left folding cylinder 12. The above described double cam mechanism can also be included generally in folding cylinders having not a horizontal position and which are not provided with pressing means acting on the folded block 50.

In order to adjust the opening and closing points of the gripping elements 131 all suitable means can be used. It is also possible to change a cam or a cam follower with another one having a different shape.

During the festooning process of the web 10 to form a block 50 of folded material, the degree of compression is measured by wire strain gauge elements 18 and 21, respectively. The degree of pressure on the block 50 is transferred to a control unit analysing the data and comparing them to the pre-set optimum pressure. If the pressure on the block 50 is too high, the control unit sends a signal to increase the speed of the lifting element 24. If the pressure on the block 50 is too low, the control unit sends a signal to decrease the speed of the lifting element 24.

Accordingly, the pressure on the block 50 can be maintained at a constant level during the festooning process. It is also possible to adjust the degree of compression

in relation to the height of the block 50, i. e. the higher the block 50 gets, the higher the pressure on the block 50.

After festooning of the block 50, the web 10 can be cut before transporting the block 50 to another station. It is also possible to move the block 50 to a rest station and to festoon another block, so that the block 50 and the other block are linked by a continuous portion of web material. A preferred embodiment of a package unit comprises two blocks 50 being connected with each other. The web 10 of these blocks is provided with perforation lines, so that a lane of the web can be easily pulled from the package unit.

Legend: mother roll 2 rollers 3 dancing roller 4 roller (guiding system) 5 roller (guiding system) 6 anvil roll 7 crush cut perforation knives 8 rolls 9 tension control system 10 web 11 cylinder R 12 cylinder L 13 gripping means R 14 pushing means R 15 pushing means L 16 gripping means L 17 fingers R 18 measuring means R 19 holder R 20 fingers L 21 measuring means L 22 holder L 23 frame (cylinders) 24 lifting element 25 pneumatic system 26 frame (lifting element) 27 motor 28 gear R 29 gear L 30 split toothed wheel L 31 split toothed wheel R 32 33 axis 34 connecting element L

35 receiving bore L 36 pin L 37 linking device L 38 eccentric fixing point 39 eccentric fixing point 40 linking device R 41 pin R 42 bore R 43 connecting element R 50 block 100 shaft<BR> 110 ribs 111 gap 130 axis 131 gripping element 132 holding member 133 spring 134 receiving element 135 first cam follower 136 first cam 137 second cam follower 138 second cam 139 holding member 140 ramp (cam 136) 141 ramp (cam 138) 142 ramp (cam 136) 150 lever 151 spring