Sander, Thomas (Rehhagenhof 48 Bielefeld, 33619, DE)
|1.||Method for supplying web material, in particular nonwoven materials, to a line used for the production of hygienic products, characterised by: unfolding and detaching a lane (9) of web material by a first driving means (16,160) from a block (6) consisting of several adjacent lanes (8,80,81,82,83) being connected with each other at end sections; guiding said lane through a storage unit (18) positioned after said first driving means (16,160) and capable of accommodating a reserve length of a lane (19) of web material ; transporting said lane (19) through a second driving means (22,23) and pulling said lane (19) from the storage unit (18) to another processing station, and controlling said first driving means (16,160) and second driving means (22,23) to keep the reserve length of the lane (19) in a predetermined range.|
|2.||Method according to claim 1, characterised in that the second driving means (22,23) transports the lane (19) at substantially constant speed and that the storage unit (18) compensates variations in the speed of the first driving means (16,160).|
|3.||Method according to claim 1 or 2, characterised in that the first driving means (16,160) pulls off a lane (9) via a partly movable transport unit (10) and that the first driving means (16,160) slows down the transportation speed when a lane is nearly finished and switches to the next adjacent lane (80,81,82).|
|4.||Method according to one of claims 1 to 3, characterised in that in case of a web break the first driving means (16,160) runs idle and the control unit issues a signal to the next processing station, causing the second driving means (22,23) to slow down the transportation of the lane (19) within a few seconds.|
|5.||Device for supplying web material, in particular nonwoven materials, to a line used for the production of hygienic products, comprising: a first driving means (16,160) for pulling off a lane of web material from a block (6) consisting of several adjacent lanes (8,80,81,82) being connected with each other at the end sections; a storage unit (18) positioned after said first driving means (16,160) and being capable of accommodating a reserve length of a lane (19) of web material ; a second driving means (22,23) positioned after said storage unit (18) for transporting said lane (19) of web material to another processing station, and a control unit for controlling the speed of said first driving means (16, 160) keeping the reserve length of the lane (19) in a predetermined range.|
|6.||Device according to claim 5, characterised in that signal means are pro vided for detecting when a lane (8) is nearly finished.|
|7.||Device according to claim 5 or 6, characterised in that the first driving means (16,160) is coupled to a movable head (10) for pulling off a lane (9) of web material, and to a signal means to slow down the first driving means (16,160) when switching from one lane (8) to the next adjacent lane (80, 81,82) of the block of web material.|
|8.||Device according to one of claims 5 to 7, characterised in that a frame (1) is provided and said first driving means (16,160) and second driving means (22,23) are fixed to said frame (1).|
|9.||Device according to one of claims 5 to 8, characterised in that the stor age unit (18) comprises a plurality of guide rollers (20,21) for storing a re serve length of the lane (19).|
|10.||Device according to one of claims 5 to 9, characterised in that the driving means comprises an electric motor and a driving roll, whereby the lane of web material is guided around the circumference of said driving roll.|
For several producing industries, in particular in the field of hygienic prod- ucts, a new material concept has been developed, known under the term "festooning". Instead of supplying a small lane or strip of a web from a roll, the web is folded to a block with several adjacent lanes. Each lane may ei- ther be cut totally or be connected to the adjacent lane by a perforated line.
Additionally, each column is connected with a splice to the next adjacent column, so that the end producer can pull off a continuous lane from the block without interrupting the manufacturing process.
Such a block of folded material is shown in WO 98/58864. The web is un- rolled, folded and afterwards cut into several lanes which are connected at the end sections with twisted splices, so that the lanes can be pulled off continuously from one side to the other side of the block.
For an optimized production process, the blocks have to be de-festooned, i. e. each material lane is unfolded column after column, and-in case of perforations-simultaneously detached from the adjacent lane by separat- ing the perforated line. In this way, an endless lane is supplied to the proc- essing station. These processing stations run at constant speed and thus require a constant supply of web material. Normally, the lane is supplied at speeds exceeding 100 meters per minute. If the lane is torn due to material deficiencies or other reasons, the end of the broken lane gets pulled into the processing machine, as the machine needs a certain time before it comes to a standstill. For re-starting the process, the beginning of the lane has to be threaded again through the guide rollers and other means incor-
porated in the supply machine and the processing machine, which is a very time-consuming and thus cost-intensive procedure. In addition, the known de-festooning machines have a fixed guiding element, so that during pulling off the lanes from a block there are considerable variations in the process conditions which often results in a web break, in particular in the lower sections of the bloXk. Flexible handling of the lane is not possible with the known de-festooning machines.
It is the object of the present invention to provide a method and a device for supplying web material which allows flexible handling of the lane during pulling off from the block, and which makes the re-starting of the process easier in case of a web break.
This object is solved with a method for supplying web material comprising the features of claim 1. By controlling the first driving means and the second driving means in a way to keep the reserve length of the lane in a prede- termined range, it is possible to handle the lane in a more flexible way. In particular, it is possible to use a movable head which is kept substantially at a constant distance to the next lane to be unfolded. When a lane has reached the bottom layer and switches to the top of the next adjacent lane, the movable head has to move up in vertical direction which takes some extra time. However, during such a switch the first driving means can slow down the operation, and the storage unit can compensate the lack of mate- rial supply. At the same time, the second driving means can continue oper- ating at constant speed in order to keep the production process at a con- stant level.
The inventive method has the additional advantage that in case of a web break, the second driving means can continue for a certain time until the next processing station is able to stop. In this way, the end section of the broken lane is positioned in the storage unit so that the threading of a new end section through the machine or the connecting of a new end section with the existing end section can be carried out easily and quickly.
The above object is solved by a device which supplies web material com- prising the features of claim 5. As the device consists of a control unit for controlling the speed of the first driving means and the second driving means to keep the reserve length of the lane in a predetermined range, the device is able to carry out the inventive method for supplying a continuous lane of web material to a production line.
In a preferred embodiment of the invention, signal means are provided for detecting when a lane is nearly finished. Thus, the first driving means can slow down before the bottom layer is reached. Optical, pneumatic or other means can be used as signal means measuring the height of the next lane to be pulled off.
Likewise, the speed of the first driving means can be reduced when the de- festooning of one block has been completed and the last lane switches to the top of another block positioned behind or side by side to the block al- ready depleted.
The driving means preferably comprises an electric motor and a driving roll, whereby the lane is guided on the circumference of said driving roll.
The invention will be described in detail with respect to the enclosed draw- ings showing different embodiments of the present invention.
Fig. 1 shows a perspective view of a device for supplying web mate- rial according to a first embodiment of the present invention; Fig. 2 to 4 show different perspective views of the device of fig. 1; Fig. 5 shows a rear view of the device shown in fig. 1; Fig. 6 shows a side view of the device shown in fig. 1; Fig. 7 shows a perspective view of a second embodiment of a device for supplying web material according to the present invention; Fig. 8 shows a front view of the device of fig. 7;
Fig. 9 shows a side view of the device shown in fig. 7; Fig. 10 shows a perspective view of a third embodiment of a device for supplying web material according to the present invention; Fig. 11 shows a side view of the device shown in fig. 10, and Fig. 12 shows a front view of the device shown in fig. 10.
A device for supplying web material as shown in Fig. 1 to 6 comprises a frame 1 in which a left position 2 and a right position 4 are provided. Within these positions, respective carriers 3 and 5 are integrated. The carriers 3 and 5 support a block 6 of folded web material which is cut or perforated into separate lanes which are connected at the end sections as shown in WO 98/58864. Each lane may be connected with the adjacent lanes by perforation lines 7 cut into the nonwoven material. The adjacent columns are connected by twisted splices.
In order to supply a continuous lane of web material, a movable head 10 is provided which guides a lane 9 between two rollers 11 having a vertical ro- tational axis. The movable head 10 is supported by a vertical bar 13 which is mounted to an upper horizontal bar 15, and a lower horizontal bar 14.
The head 10 can be moved in vertical direction by rollers 12 which are sup- ported at the vertical bar 13. The vertical bar 13 can be moved in horizontal direction by driving means 24 which engage corresponding drive means (not shown) connected with the bar 13.
In order to unfold lane 9 from the block, a driving means 16 is provided whereby a part of the lane is wound around a drive roller 160. The lane is guided via several guide rollers 17 outside the frame 1 to a storage unit 18.
The storage unit 18 comprises a vertically extending input lane 19 which is wound around upper rollers 20 and lower rollers 21, so that a certain length of web material is stored. At the outside of the storage unit 18, a driving means 23 with a drive roller 22 is provided which moves the lane at con- stant speed and supplies it to another processing station. The lower guide rollers 21 are movable in vertical direction; when the driving means 16
slows down or stops the supply of web material, the output of the storage unit 18 remains constant due to the driving means 23. With a certain delay, the driving means 23 slows down in order to interrupt the manufacturing process.
Lane 9 of the block is unfolded at relatively constant speed, so that lane 8 which is the next to be unfolded, is constantly getting lower. Thus, in order to maintain similar geometric configurations between the movable head 10 and lane 8, the head 10 moves downwards at approximately the same speed as lane 8 decreases in height.
As soon as the lane is getting to the bottom layer, a signal is activated which causes a control unit to slow down the driving means 16 in order to reduce the speed for unfolding lane 9. However, with the output of the stor- age unit 18, the lane continues to be supplied to the production line at con- stant speed, as the guide rollers 21 move upwards. Simultaneously, the movable head 10 is moved to an upward position as fast as possible. When the unfolding process starts at the top of the next adjacent lane 18, the head 10 is again in a position above the block 6. Thus, constant unfolding conditions for processing lane after lane are guaranteed. Afterwards, the driving means 16 accelerates the unfolding process, and the storage unit 18 fills again with the missing length of lane storage. As soon as lane 80 is totally pulled off the block 6, the adjacent lane 81, and successively lanes 82 and 83 are unfolded. When the last lane 83 is depleted, the movable head 10 moves from the lowest position to the highest position, and hori- zontally to the front of the left block 6 with lane 84, which is the next lane to be unfolded. When switching from one block to another block, the driving means slows down the speed of web material supplied to the storage unit 18.
When de-festooning of block 6 is finished, the carrier 5 is empty and can be moved outside frame 1 as indicated by the arrow. Another carrier can be introduced into frame 1 supporting a new block 6 of folded web material.
The last lane 85 of the left block 6 is connected again with the front lane of the new block positioned inside frame 1.
The carriers 3 and 5 are supported by four wheels 27 in order to allow a shifting of the carriers 3 and 5. Both carriers are provided with a holding element 26 which supports a block 6 of folded material in an inclined posi- tion. The inclination can be adjusted by means 25 at the rear side of the carriers 3 and 5. Due to frictional forces during the unfolding of lane 9, which may affect adjacent layers of web material below the lane to be un- folded, it is preferred that the blocks are in an inclined position so that the gravity acts against the pulling force of such frictional engagement. Also, the adjacent lanes 8,80 etc. may be connected by perforations; without inclination of the blocks ; it is more likely that a wrong perforation line is de- tached between two lanes, or that several lanes are pulled off at the same time, resulting in damages of the material or process instability.
Fig. 7,8 and 9 show a second embodiment of a device for supplying web materials according to the invention. If the same reference signs are used as in the first embodiment, the relevant parts are identical in both embodi- ments.
According to the second embodiment, frame 1'comprises opposite posi- tions for two carriers 3 and 5 with blocks 6 of folded material. In this em- bodiment, both carriers 3 and 5 are integrated into frame 1'from opposite sides, whereby a movable head 10'is positioned between both carriers 3 and 5. The movable head 10'is mounted on a vertical bar 13'which is fixed to frame 1'. In this embodiment, the movable head 10'moves only in vertical direction. Lane 9 is pulled from a block 6 and passes through verti- cal rollers 11'and several guide rollers to a driving means 16'. Afterwards, the lane is guided to a storage unit 18.
In this embodiment, block 6 of folded material is continuously supplied in lanes to the storage unit by pulling off lanes 8,80,81 etc. successively. The
angle a, defined by a plane of lane 8, which is the next lane to be unfolded, and lane 9 which is fed to the movable head 10', is in a predetermined range between 25° to 65°, preferably 40° to 50°. When the last lane 83 of block 6 has been unfolded, the device switches to the first lane 84 of the new block 6 as shown in Fig. 8. Then the carrier 5 is removed from the de- vice and a new carrier with another block is positioned within frame 1'. By connecting the first lane of the new block with the last lane of the current block, the device can supply lanes of web material in a continuous process.
In Fig. 10,11 and 12 a third embodiment of the present invention is shown.
In this embodiment, the block 6 of folded material is supplied from a rear side and transported to the movable head 110, and corresponding driving means 116 for unfolding lane 8 next to the movable head 110 are provided.
This configuration has the advantage that block 6 can be continuously de- festooned, with unfolding lanes 8,80,81,82... 87 etc. successively. The movable head 110 is mounted on a vertical bar 113 which is fixed to the frame 101. The operation of pulling a lane 9 off the block 6 is carried out as in the foregoing embodiments.
The blocks 6 are transported from the end sides of a horizontal carrier 103 via driving means 102 to an inclined carrier 105 having driving means 104.
Thus, the blocks 6 are in an inclined position when the front lane 8 is pulled off from the respective block 6. The angle a between the plane of lane 8 to be unfolded next, and lane 9 is in the range between 25° and 65°.
Instead of providing a single movable head comprising two rollers with a vertical rotational axis, several movable heads of reduced width can be pro- vided.