Apparatus and method for forming a block of folded material

Abstract: An apparatus and a method for forming a block (5) of folded material are provided, whereby the apparatus comprises means (2, 3) for folding a web (4) to a block (5), means (10) for holding an end (7, 7') of the web (4) from the bottom layer of the block (5) and an automatic cutting mechanism (9, 11, 13) for providing an end portion (14) from the uppermost layer of the block (5). According to the method a web (4) on a receiving element (6) is folded until a portion of the web (4) forms a block (5) of desired height and the uppermost web layer is fed to a cutting mechanism (9, 11, 13). Then the uppermost web layer is cut and the end portion (7, 7') from the bottom layer of the block (5) is at least partly laid on top of the block (5). Due to the inventive apparatus and method it is possible to automatically handle web material for forming a block without manual operation, which is particularly important for hygienic products.

Description: The present invention refers to an apparatus and a method for forming a block of folded material. Such an apparatus and method are preferably used in the production of festooned packages which are in particular used in the hygienic industry whereby the web can be made of non-woven fabric or airlaid material. WO 98/58864 discloses a package of festooned web material which is cut into several stacks, whereby the end of each stack is accessible for connection with another end portion of a stack. In order to provide a free end portion from the bottom of the stack, a strip portion is pulled from underneath the stack. This operation to provide a free end portion has to be carried out manually which means that someone has to grip the end portion and arrange it in the preferred position. This is a serious inconvenience since the festooned packages are preferably used in the hygienic industry where clean handling of the material is crucial and the elimination of manual operations is always considered as a high benefit. In addition, for being able to pull out a strip from the bottom of the stack, it is required to flip the festooned block, which is a time-consuming procedure. US 4 499 707 discloses a method and an apparatus for baling a tow of textile filaments, in which when a container has been filled, the tow is cut automatically in such a way that the end of the cut tow connected to the tow in the container falls on the side of the container. Thus, the end of the tow can be gripped. It is not disclosed to fold a web to a block and the means for provided to insert the tow into the container do not allow an effective handling of the material. Accordingly, it is the object of the present invention to provide an apparatus and a method for separating the web from a block of folded material which can be used for hygienic products and which are more effective in handling the web after the festooning of one block is completed. This object is solved by an apparatus having the features of claim 1 and a method comprising the features of claim 7. Due to the fact that the apparatus comprises means for holding an end of the web from the bottom layer of the block and an automatic cutting mechanism for providing an end portion from the uppermost layer of the block, manual handling of the web is eliminated during the whole process. This is particularly important for the production of materials intended for use in hygienic products like diapers and other sanitary products. In addition, the automatic handling of the web reduces downtime of the production line and thus increases the efficiency. Holding means are integrated in the apparatus so that the end portion from the bottom layer can be laid on top of the block without flipping the whole block of material. According to the embodiment of the invention the holding means comprise a roller for winding and unwinding a portion of the web. This allows effective handling of the web due to the fact that, with the increasing height of the block being formed, also the length of the end portion increases as required, so that a continuous unwinding of the end portion helps to avoid loose end portions hanging around. If the block is formed on a receiving element which is movable in horizontal direction to an adjacent processing station, the downtime of the folding mechanism can be minimised during the cutting operation. Alternatively, it is possible to use a conveyor to release the block of folded material in horizontal direction. For effective and highly accurate cutting of the web, the cutting mechanism comprises a sledge and a cutting knife being movable on the sledge. The knife can be rolled on the web contacting the sledge to cut the web so that the material stress is minimized during the cutting operation. In order to obtain a clean cut, a clamping bar can be provided for fixing a web portion on the sledge. According to a preferred embodiment, the holding means comprise a needle roller having protruding needles which are insertable into the web. This enables the apparatus to handle the web without an additional clamping mechanism which would increase the risk of damaging the material. The protruding needles can be small enough in diameter to avoid any damage, since the web of airlaid material or non-woven fabric is relatively light. In order to avoid damage of the needles during rotation of the needle roller, the sledge is provided with notches through which the needles of the needle roller can pass during its rotation. This guarantees that the needles are not in contact with the sledge which could cause the breaking of a needle and require to dispose the whole block of web material, if a broken part of the needle gets into the block. In order to assure removing of the web portion during unwinding of the roller, strip-off means are provided adjacent to the roller of the holding means, to facilitate the final release of the web from the roller. According to the inventive method the web is folded on a receiving element until a portion of the web is layered in form of a block of desired height. At this-moment, the uppermost web layer is fed to a cutting mechanism and is cut, whereby the end of the bottom layer is laid at least partly on top of the block. According to the embodiment of the inventive method, an end portion from the bottom layer of a block is withheld on a holding means before starting the formation of the block so that during block formation the holding means can hold a sufficient part of the web to arrange an end portion at the side of the block, since the height of the block increases during the block formation. In order to assure that the end portion from the bottom of the block is laid down on top of the block, the block is moved in horizontal direction so that the holding and releasing of the end portion results in laying down the end portion on top of the block. Preferably, the uppermost web layer is cut and its end portion falls down on one side of the block. In particular if the web is perforated so that different lines of the web can be pulled from the festooned block, it is preferred to connect the different lines of the block of folded material. Such a splicing operation can only be carried out when the connecting portions have the required length, as pulling off the end portions from the stack could damage the web. The invention will now be described in detail with respect to the appended drawings showing an embodiment of the apparatus and the method according to the invention. Fig. 1 is a schematic side view of the inventive apparatus according to a first embodiment; Fig. 2 is a schematic side view showing a beginning of the method for providing loose end connecting portions on top of a block of folded material; Fig. 3 to 9 show different steps of the method for forming a block with loose ends arranged partly on top of the block; Fig. 10 is an enlarged side view of the main parts of the means for handling the web, and Fig. 11 is a top view on the sledge and the needle roller of the inventive apparatus. As shown in Fig. 1 the apparatus for forming a block of folded material comprises a frame 1 to which a left folding cylinder 2 and a right folding cylinder 3 are mounted. Between the folding cylinders 2 and 3, a web 4 of airlaid material passes whereby the web 4 is gripped and folded by a rotation of the folding cylinders 2 and 3 to form a block 5. The block 5 is arranged on a receiving element 6 which is movable and preferably formed as a lifting element. The bottom layer of the block 5 has an end portion 7 which is withheld by a tail holding roller 8. On the upper left side of the block 5 a sledge 9 is provided, which is movable in horizontal direction. The sledge 9 is guided on a rail system and moved by an electric drive system (not shown). On the upper right side of the block 5 a needle roller 10 is provided. Below the needle roller 10 a clamping bar 11 is provided which is movable in horizontal direction. Before starting with the cutting operation for block 5, the finished block 12 is removed from the position shown in Fig. 1. The starting position for separating the web from a block 5 of folded material is shown in Fig. 2. In the beginning, the block 5 is moved horizontally from the receiving element 6, so that the block 5 passes under the tail holding roller 8 and the end portion 7 is laid down on top of the block 5 (Fig. 3). The horizontal movement of block 5 can either be achieved by moving the receiving element 6 or by using per se known conveyor means. As shown in Fig. 4, the block 5 is completely moved beyond the tail holding roller 8 so that the end portion 7 from the bottom layer of block 5 is arranged on top of the block 5. Then the sledge 9 begins to move under the folding cylinders 2 and 3 to the clamping bar 11. Simultaneously, the tail holding roller 8 is moved in the same direction as the sledge (Fig. 5). In order to cut the web 4, the sledge 9 is moved under the needle roller 10 and the clamping bar 11 clamps a portion of the web to the sledge 9 (Fig. 6). In this position, the needle roller 10 rotates so that at least some needles are inserted into the web and falling down of the web 4 after cutting is avoided. Then a cutting element 13 is moved on the sledge 9, separating the web 4 at this position. The cutting element 13 can comprise a rolling knife in order to reduce frictional engagement of the cutting element 13 on the sledge 9. At the cutting area, the sledge 9 is made of hardened steel to reduce the wear of this part. As shown in Fig. 7, an end portion 14 is provided after cutting the web 4. Both end portions 7 and 14 are laid down at least partly on top of the block 5, so that they can easily be detected and gripped for further processing of the folded web. The other part of the web 4 forms another end portion 7' which is fixed to the needle roller 10. The sledge 9 returns from the position under the needle roller 10 to the original position shown in Fig. 2. As shown in Fig. 8, the needle roller 10 turns around its axis to provide an end portion 7'of sufficient length before starting to build another block. This winding process is followed by the folding cylinders which release a sufficient portion of the web. In addition, the tail holding roller 8 is moved to the left side under the needle roller 10. In Fig. 9 the starting position for forming a new block of folded material is shown. The new end portion 7' from the bottom of the new block is partly unwound from the needle roller 10 and hangs between the needle roller 10 and the tail holding roller 8. Due to the rotation of the folding cylinders 2 and 3, the new block is built and the receiving element 6 moves downward, pulling a part of the end portion 7' on the side of the new block. After forming the new block, the same position as shown in Fig. 2 is reached and a new cycle begins. In Fig. 10 an enlarged view of the main parts of the cutting system is shown in the position similar to Fig. 7. The cutting element 13 is provided with a cutting edge 21 contacting the hardened surface of the sledge 9. The web is clamped between the sledge 9 and the clamping bar 11. The needle roller 10 comprises recessions 22 with needle holders 16 in which needles 15 are mounted, protruding in an inclined direction with respect to the radial direction. The needle roller 10 comprises a cylinder 17 in which the recessions 22 are integrated for locating the needle holders 16. A rotation of the needle roller 10 results in an insertion of some needles 15 into the web 4. This ensures holding of the web 4 by the needle roller 10. As shown in Fig. 11 the sledge 9 disclosed on the bottom side comprises notches 18 which are slightly wider than the diameter of the needles 15. On the upper side of Fig. 11 the needle roller 10 is shown. During the rotation of the needle roller 10, the needles 15 pass through the notches 18, so that a contact of the needle 15 with the sledge 9 is avoided. As the web 4 is withheld between the sledge 9 and the needle roller 10, the needles 15 are inserted into the web 4. As can be seen in Fig. 11, the sledge 9 is driven by belts 19 and 20 which are engaging two toothed wheels driven by a motor (not shown). In a further embodiment of the apparatus, strip-off means are arranged at the needle roller 10 to assure that the web is released when the needle roller 10 rotates in an unwinding direction. The strip-off means can be made of one or more rollers guiding the web 4 in the desired direction.

Claims: Apparatus for forming a block (5) of folded material, comprising: means (2, 3) for folding a web (4) to a block (5); means (10) for holding an end (7, 7') of the web (4) from the bottom layer of the block (5), whereby the holding means comprise a roller for winding and unwinding a portion of the web (4); an automatic cutting mechanism (9, 11, 13) for providing an end portion (14) from the uppermost layer of the block (5), and a receiving element (6) on which the block (5) is formed whereby the receiving element (6) is movable both in vertical and in horizontal direction. Apparatus according to claim 1, characterised in that the cutting mechanism comprises a sledge (9) and a cutting knife (21) being movable on the sledge (9). Apparatus according to claim 1 or 2, characterised in that the cutting mechanism comprises a clamping bar (11) for fixing a web portion on the sledge (9). Apparatus according to one of claims 1 to 3, characterised in that the holding means comprise a needle roller (10) having protruding needles (15) which are insertable into the web (4). Apparatus according to one of claims 1 to 4, characterised in that the sledge (9) is provided with notches (18) through which the needles (15) of the needle roller (10) can pass during its rotation. Apparatus according to one of claims 1 to 5, characterised in that strip-off means are provided adjacent to the roller (10) of the holding means for removing the web (4) from the roller (10). Method for forming a block (5) of folded material providing loose ends (7, 14) accessible for connection comprising the following steps: folding of a web (4) on a receiving element until a portion of the web forms a folded block (5) of desired height; feeding the uppermost web layer to a cutting mechanism (9, 11, 13); cutting the uppermost web layer to form an end portion (7, 7'); laying the end portions (7, 7') from the bottom layer of the block (5) at least partly on top of the block (5); withholding an end portion (7) from the bottom layer of the block (5) on a holding means (10) before starting to form a new block (5) and unwounding the end portion (7) being withheld on the holding means (10) during the forming of the new block (5). Method according to claim 7, characterised in that after forming of the block (5) the receiving element (6) is moved in horizontal direction and the end portion (7) from the bottom layer is laid on top of the block (5). Method according to claim 7 or 8, characterised in that the uppermost web layer is cut and its end portion (14) falls down on one side of the block (5).

Inventors: SANDER THOMAS, SANDER, THOMAS
Applicants: GEVAS VERPACKUNGSMASCHINEN GMB, GEVAS VERPACKUNGSMASCHINEN GMBH
Application year: 2001
Main classification: B65H45
IPC codes: B65H45