EP0970014A1

EP0970014A1 - A method and an arrangement for collecting a strip-formed material

Info

Publication number: EP0970014A1
Application number: EP98912866A
Authority: EP
Inventors: Gösta Andersson
Original assignee: Gosta Andersson Konsult AB
Current assignee: Duni AB
Priority date: 1997-03-27
Filing date: 1998-03-26
Publication date: 2000-01-12
Also published as: WO1998043907A1; AU6755498A; SE508481C2; SE9701165D0; SE9701165L; CA2288018A1

Abstract

The invention relates to a method and a device for assembling, in a packing unit (1) having at least one support surface (5), a high-bulk paper tape or paper strip (2), preferably in the form of a sanitary product for the absorption of body liquids. The assembling takes place by so-called taffling, involving that the strip (2) is positioned in a zig-zag pattern like a flat spiral with a pitch preferably corresponding to the width of the strip (2). The method is characterized in that the taffling is initiated in a left-hand or right-hand corner of the support surface (5), over which the strip (2) is assembled. An incoming strip end (9) is fixed in said corner so that it, and also an outgoing strip end (10), becomes conveniently accessible from outside the unit (1) for the purpose of connection with the incoming and/or outgoing strip end of a succeeding unit. The device according to the invention consists of a strip distributor (14) comprising at least two opposed, endless feeding means (17, 18), between which the strip (2) to be assembled is fed down towards the contact surface (5). Each of the feeding means has a length substantially corresponding to twice the deposit length of the strip and exhibits at least one gripping member (19; 20) and one insertion knife (21, 22) cooperating with it and projecting from the opposite feeding means for the purpose of keeping the strip (2) temporarily gripped during its delivery in a reciprocating movement over the length of the support surface (5). The strip distributor (14) is laterally displaceable during the delivery movement.

Description

A method and an arrangement for collecting a strip-formed material

The present invention relates to a method and a device for assembling in at least one package unit a high-bulk paper tape or paper strip, preferably forming a sanitary product for the absorption of body liquids.

The manufacturers of certain sanitary products for the absorption of body liquids often wish to use high-absorbing, air-laid paper qualities in order to simplify the manufacturing process. Many of those paper qualities are characterized by a high bulk, about 1-3 nuns, in combination with small webs around 50-70 m s. Those parameters consequently limit the maximum reel diameter and, for that reason, also the reel content expressed in the number of length units. The reel volume will therefore in respect of certain high-bulk qualities be limited to 250-300 running meters which, when converter machines operating at web speeds of 400 m/min are used, means that such a roll must be exchanged already after approximately 45 seconds. Since the terminal end of the reel always is fixed to the surface of the core, around which the reel is built up, no joining can take place until the reel is consumed and the terminal end free. This naturally presents considerable problems requiring frequent reel exchanges.

The object of the present invention is to provide a method and a device of the type above referred to with elimina- tion of the above-mentioned problems. The characteristics of the invention are set out in the annexed claims.

Thanks to the invention there is no longer necessary to perform frequent exchanges of reels with high-bulk paper tapes or paper strips because those are, instead of being rolled, assembled by so-called taffling involving that the strip is delivered in a zig-zag pattern as a flat spiral with a pitch preferably corresponding to the width of the strip. During the delivery of the strip by means of a device according to the invention the strip can be fixed in position both with the aid of vacuum and/or with depression bands. Further, incoming and outgoing strip ends are located in such a manner that they can easily be joined to a previously assembled strip stack in a package unit.

The taffling preferably takes place on a support surface in the shape of a bottom plate and, in order to maintain the delivered strips in position during the taffling, a moving vacuum will act along both lateral sides of the taffled stack. This can be combined with tapes attached external to the package unit, whereby during the reciprocating traversing of the strip delivery device over the bottom plate the bands will press down and keep in place the underlying layers of the zig-zag strip. During the delivery of the strip by means of the distributor according to the invention one does continuously lower the bottom plate supporting the underlying stack of zig-zag strips, until the stack is completed. The vacuum used at the delivery is especially intended to act upon the strip end fold to keep it by suction pressed against a grid always with level with the top layer of the stack. The distributor device proper consists of two endless cog- belts, each having a length substantially corresponding to twice the strip delivery length. Further, each of said cog-belts are provided with a gripping member and with an insertion knife used in connection with the gripping member keeping the strip fixed. Upon completed taffling of the package units the strip ends are located in such a pattern that a number of taffled package units inlined after each other can at their input strip ends be joined with the output strip ends of the succeeding package unit so that a continuous strip web can be established without the need of any stops for reel exchange and joining.

Thanks to the present invention the running time for a unit is increased from 45 seconds to 540 seconds with a further advantage that joining with the succeeding unit can be carried out already before the unit in the process of being emptied has been completely consumed.

A preferred embodiment of the invention will now be described with reference to the drawing, in which

Fig. 1 is a side-view illustrating how incoming and outgoing strips are located along opposite sides at an angle to the bottom forming the support surface so that the package unit can be formed by a plurality of layers. Thereafter a top-plate has been placed thereon to help compress the stack formed, which is then banded and surrounded with a plastic protection cover,

Fig. 2 shows an end-side of the stack illustrated in Fig. 1 having the outgoing or incoming strip end conveniently available,

Fig. 3 shows the stack illustrated in Figs 1 and 2 seen from above, the lateral walls of the stack being shown in dash lines, whereby the incoming and outgoing strip ends, respectively, are placed opposite to each other to facilitate connection with a succeeding package unit, Fig. 4 does diagrammatically show how the distributor device can traverse over the stack formed simultaneously with depression of previously delivered strips by means of a tape passing over the distributor device and intended, in cooperation or in combination with vacuum, to keep the underlying zig-zag strip layers in position with simultaneous downward displacement of the underlying stack after the formation of each strip layer,

Fig. 5 is a diagrammatical lateral view of a distributor device according to the present invention and shows how the strip is captured by gripping members in the distributor in connection with the delivery of the strip on the underlying stack,

Fig. 6 is a top-view of the distributor device shown in Fig. 5 and here diagrammatically indicated by a black dot field with the underlying stack,

Fig. 7 is a diagrammatic partial lateral view of a gripping member forming part of the cog-belts in the distributor device,

Fig. 8 shows the gripping member illustrated in Fig. 7 while passing a direction-changing roll causing the gripper to open up automatically.

As appears from Figs 1 and 3 , there are in different views shown a high-bulk paper tape or paper strip 2 being assembled in a package unit 1, preferably in the form of a sanitary product for absorption of body liquids. The assembling has taken place by so-called taffling, involving that the strip 2 is positioned in a zig-zag pattern as a flat spiral with a pitch or overlapping preferably corresponding to the width of the strip 2 and, more precisely, being equal to or greater than the strip width. Fig. 1 shows how an input strip 2 passes along one lateral side 3 towards a bottom plate 6 forming a support surface 5 and thereafter builds up the package unit 1 in a plurality of layers. When the zig-zag positioning on the bottom plate 6 is completed, a top-plate 7 is placed on the formed stack 8, which is thereafter compressed, and provided with bands and with plastic protection cover. Fig. 2 shows the package unit 1 in Fig. 1 as seen in a lateral view and illustrating how the input 9 and output 10, respectively, strip end becomes conveniently available at the stack sides 3 and 4. Fig. 3 shows how the incoming and outgoing strip end 9, 10, respectively, are positioned, preferably opposite to each other in order to facilitate the connection with a preceding and a succeeding package unit l.

When the strip 2 is taffled over the stack 8 by means of a delivery device in the shape of a strip distributor 14, it may be suitable in addition to vacuum also to use fixation and depression bands 11 to achieve position fixation of the delivered strip 2 and in the process there are consequently fixed previously delivered strip sections 16 both laterally and in the underlying layers. The end edges of the bands 11 are secured in points 12, 13 external to the package unit 1 and bands 11 roll around the circumference of the distributor device 14 with the aid of small rollers 15 as shown in Fig. 4. In this way the distributor 14 can reciprocate over the support surface 5 with bands 11 simultaneously extending transversely to the delivered strip sections 16. In this way the bands 11 depress the uppermost strip sections 16 during the taffling, the package unit 1 with an underlying, completed stack 8 of zig-zag strip sections 16 being at the same time continuously displaced in the downward direction.

Fig. 5 does diagrammatically show a distributor device 14 according to the present invention, comprising two opposed endless feeding means in the shape of cog-belts 17, 18, between which the strip 2 to be assembled is fed down towards the support surface 5. The length of each of the cog-belts 17 and 18 substantially corresponds to twice the strip delivery length and each of the cog-belts 17 and 18 includes at least one gripping member 19; 20 and an insertion knife 21; 22 projecting from the opposite cog-belt and cooperating with the gripping member 19; 20 for temporarily gripping the strip during the reciprocating distri- bution movement along the length of the support surface. In order to match the speed of the gripping members to that of the cog-belts they can be given a length amounting to about 90% of the belt loop deposited. In order to place the strip 2 in a zig-zag pattern when deposited over the support surface 5 the distributor 14 is laterally movable across the delivery length and by a predetermined distance for each strip delivery length until all of the support surface 5 has become covered.

As appears from Fig. 5, the passage direction of each cog- belt 17, 18 is changed by three rollers 23, 24, 25; 26, 27, 28 and a guide member 29; 30 constituted by a curved bow, over which the belts can pass without opening up the gripping members 19, 20. The radius of curvature of this bow must be mentioned in relation to the opening function of the gripping members in combination with the tension of the cog-belts. Alternatively, this curved bow may also include a number of direction-changing rollers. The tension in the cog-belts 17, 18, respectively, is according to the embodiment here shown maintained by means of two tensions wheels 31 and 32. Accordingly, each cog-belt 17, 18, respectively, does on its external side have a gripping member 19, 20 and an insertion knife 21, 22, the relative positioning of which is selected so that the knife 22 on the one cog-belt 18 always agrees with the gripping member 19 on the other belt 17. At the spot 33, where the strip 2 enters the distributor device 14 the cog-belts pass over two direction-changing rollers 23 and

26, mounted at a distance from each other permitting that the insertion knife 22 on the one cog-belt 18 can be pressed inwards together with the strip 2 then to be delivered into the gripping member 19 on the other cog- belt 17 open at that time. Further, a second roller 24,

27, respectively, for each cog-belt is mounted in the area immediately above the outer edges 34, 35 of the support surface whereby, when the cog-belt is bent over the roller 24, 27, the related gripping member opens up so that the strip is released and by vacuum sucked down to the support surface. This vacuum is set up by means of vacuum nozzles 36, 37, located at the folding points 38, 39 near the outer edges 34, 35 of the support surface 5. This vacuum keeps in place both the strip 2 under delivery and the adjacent previously folded strip ends or folds 38, 39.

According to the embodiment illustrating the rollers 23, 26 mounted at the strip inlet spot 33 are driving. Above them there are two feeder rolls 40, 41, which feed the paper strip from a storage reel not shown in the drawing. The cog-belts 17, 18 are bent over the driving cog-belt wheels so that the insertion knife 22 on the one cog-belt

18 can press a paper strip into the opened gripping member

19 on the other cog-belt 17. As appears from the figure, according to this embodiment the length of cog-belts 17 , 18 is twice the taffled length A-B. Fig. 6 illustrates how the strip-distributor 14 is movable over the stack 8 below the deposit surface. Also shown is the location of the vacuum nozzles 36, 37 in relation to the strip-distributor 14. This vacuum from the nozzles 36, 37 has its greatest value when the gripping members release the extracted strip in connection with the folding at the lateral surfaces 3, 4. Accordingly, this release of the strip 2 takes place when the cog-belt is bent over the outer rollers 24, 22 adjacent the nozzles 36, 37 at the upper shorter sides of the stack. The strip end fixation vacuum should through their vacuum nozzles act along an effective length approximately corresponding three times the width of the strip. Fig. 6 does also show the presence of a grid or a perforated post 42, 43 located at the lateral surfaces 3, 4. The strip ends 38, 39 rest against that grid or post or are sucked towards it by the vacuum nozzles moving immediately outside. In the very moment when one of the gripping members opens up during the zigzag delivery of the strip and the end folding near the grid 42; 43 the air stream towards the vacuum nozzle will jerk the released strip end towards the nozzle. This occurs during the traversing movement of the strip distributor 14 above the deposit surface in the direction C-C. Thanks to the fact that the vacuum nozzles 36, 37 have such a width and height that the previously delivered strip sections 16 will be sucked together the result is a very stable unit. Another result is the formation of a straight correctly shaped stack of taffled strips. Since the taffling equipment is moved laterally by a distance corresponding to about the strip width for two taffling lengths, i.e. is reciprocating, the taffled strip 2 in an underlying layer will be locked in position by the next layer. These locking forces are increased when the taffling in one strip layer is reversed or directed trans- versely in relation to the next layer. As a matter of principle two such layers form a firmly integrated, X- shaped bond.

According to the invention the assembling of the high-bulk paper tape or paper strip takes place in the following way. With the aid of the strip-distributor 14 according to the invention the assembling occurs by so-called taffling, the strip being deposited in a zig-zag pattern as a flat spiral with a pitch preferably corresponding to the width of the strip. The taffling is initiated when the strip has been fed down through the strip-distributor 14 and between the two cog-belts 17 , 18 so that the incoming strip is fixed in the left-hand or right-hand corner of the support surface 5 concerned. Feeder wheels 40, 41 then continue the downwardly directing feeding of the strip 2 at the same speed as that of the cog-belts with their gripping members which, aided by the insertion knives, grip the strip 2 and feed it at the same speed. When the gripping member leaves its roller and the insertion knife 21, 22 is retracted therefrom, the gripping member holds the strip and guides it along the curve-shaped bow to the lateral side of the support surface. The strip is released there when the cog-belt is broken over the lowermost roller 24; 27, the vacuum at that side simultaneously keeping the strip fixed in position during its folding. At the same time the opposite end of the strip section is again ceased by a gripping member 20 on the opposite cog-belt 18 at the driving cog-belt wheels 23, 26, this gripping member 20 dragging the strip in the opposite direction to the lower roller 27, which is located at the opposite side of the support surface 5, whereupon all of the length of the strip section 16 is extended. This procedure is repeated and carried out simultaneously with the strip-distributor 14 moving transversely to the distribution direction until all of the stack 8 is completed. As mentioned before, also the transverse bands 11 are used to press down the delivered strip material in connection with the delivery of the strip 2. The support surface 5 for the stack 8 is formed on a bottom plate 6 of a suitable material and, since it must be possible to compress, band and plastic- seal the taffled stack 8, the plate 6 should tolerate the strains, to which it will be exposed, e.g. during transport. The plate does also act as a protective layer upwards and downwards and also as a lateral protection.

Figs 7 and 8 show the appearance of the gripping members 19; 20 on the respective cog-belts 17; 18 in a closed or locking position and in an open position when the cog-belt 17; 18 passes over a roller 24; 27.

Claims

1. Method for assembling, in at least one package unit (1) having a support surface (5) , a high-bulk paper tape or paper strip, preferably in the shape of a sanitary product for the absorption of body liquids, the assembling being carried out by so-called taffling in the way that the strip (2) is arranged in zig-zag as a flat spiral with overlapping or pitch preferably corresponding to the width of the strip (2) , characterized in that the taffling is started in a left or right corner of the support surface (5) , over which the assembling of the strip (2) takes place, an input strip end (9) being fixed in said corner so that it, and also an output strip end (10) , becomes conveniently accessable external to said unit (1) for the purpose of joining it with the input and/or output strip end of a succeeding unit.

2. Method as claimed in claim 1, characterized in that the incoming and outgoing strip ends (9, 10) of a package unit (1) are placed opposite to each other and at the same distance from the left or right corner of the support surface (5), whereby interconnection of the strip ends (9, 10) of two adjacent units can conveniently be carried out manually or automatically.

3. Method as claimed in claim 1, characterized in that the taffling is carried out by means of a distributor device (14) , vacuum and/or fixation bands (11) being used to fix in position previously deposited strip sections (16) both laterally and vertically.

4. Method as claimed in claim 3 , characterized in that said fixation bands (11) are at their end edges firmly secured in points (12, 13) external to the package unit (1) , said bands (11) travelling around the circumference of the distributor device (14) during its delivery movement across the longitudinal direction of the package unit (1) formed by the strips, said bands (11) continuously keeping the uppermost strip sections (16) depressed during the taffling simultaneously with the package unit (1) , including the underlying, completed stack (8) of zig-zag positioned strip lengths (16) , being continuously moved in the downward direction.

5. Device for assembling, in at least one package unit having a support surface, a high-bulk paper tape or paper strip, preferably in the shape of a sanitary product for the absorption of body liquids, the assembling being carried out by so-called taffling in the way that the strip (2) is arranged in zig-zag as a flat spiral with overlapping or pitch preferably corresponding to the width of the strip, characterized by a strip distributor (14) comprising two opposite to each other acting, endless feeding means (17, 18), between which the strip (2) to be assembled is fed down to the support surface (5) , each of said feeding means (17, 18) having a length substantially corresponding to twice the strip distribution length and comprises at least one gripping member (19, 20) and an insertion knife (21, 22) cooperating with the gripping member and projecting from the adjacent feeding means for temporary gripping of the strip (2) during its reciprocating delivery along the length of the support surface (5) , said strip distributor (14) being, during the delivery of the strip (2) , simultaneously laterally displaceable by a predetermined distance transversely to the delivery direction for each strip delivery section until all of the support surface has become covered.

6. Device as claimed in claim 5, characterized in that said feeding means are constituted by at least one continuous belt (17, 18) passing over at least two direction- changing rollers, said belt being guided along a curve- shaped bow above the support surface (5) between two rollers (23, 24; 26, 27) with the aid of a guiding device (29, 30), the belt simultaneously being kept in a tension- ed condition over said rollers and the guiding device by means of a belt-tension device (31, 32) , the gripping members (19, 20) mounted on the belts (17, 18) being, thanks to the small diameter of said rollers, arranged automatically to be opened in connection with the gripping and the release, respectively, of said strip (2) .

7. Device as claimed in claim 6 , characterized in that each belt is constituted by a cog-belt (17, 18), on the outer side of which the gripping member (19, 20) and the insertion knife (21, 22) , respectively, are located in such positions relatively each other that the knife on the one cog-belt always agrees with the gripping member on the other belt, the cog-belts getting, at the strip (2) entry position (33) in the distributor (14) their directions changed by two rollers (23, 26), arranged in such a mutual distance that the insertion knife (22) on the one cog-belt (18) can, together with the strip (2) , be pressed in into the then open gripping member (19) of the other cog-belt (17).

8. Device as claimed in claim 6, characterized in that a second direction-changing roller (24; 27) of the respective cog-belt (17, 18) is located in the area close above the outer edges (34, 35) of the support surface (5) so that a bending of the cog-belt when passing over the roller opens up the gripping member for releasing the strip.

9. Device as claimed in claim 8, characterized in that the vacuum nozzles (36, 37) are located at the strip folds near the outer edges (34, 35) of the support surface (5) for fixation of the strip (2) and of its folded strip ends (38, 39) .