Patent Application
20090289407
The present invention relates to the production of paper material in stacks of interfolded sheets, and, in particular, it relates to a structure of interfolding machine adapted to process sheets of different length.
As well known, in the paper converting industry a variety of types is used of machines and of processes for making paper tissues, paper towels and similar articles in stacks of a certain height of interfolded sheets.
They are obtained stacking the sheets in an “interfolded” way, i.e. at each fold a wing of the previous sheet and a wing of a next stack sheet engage with each other. This way, when drawing a sheet from a package, at the moment of the use, also a wing of a next stack sheet is dragged up to protruding from the package, with subsequent practical employment for certain types of users. Among possible interfolding ways the L-type, with 2 panels (single fold), or the Z or W types, respectively with 3 and 4 panels (multi fold), are known.
The interfolding machines use one or more webs of paper, which from one or more large rollers and which are cut into sheets and then supplied offset with respect to one another on folding counter-rotating rollers.
More precisely, the webs are cut into sheets by means of cutting rollers that interact alternatively, with relative counter-support blades. In case of L-type interfolding (single-fold) the webs are cut to form a shifted succession of sheets coming preferably from two different directions. Then, the sheets coming from either directions are fed in an alternated way to the folding rollers, so that each sheet coming from the first direction is overlapped with a portion of the sheet coming from the second direction, and vice-versa.
The sheets coming from the two directions, in order to be overlapped in the way above described, adhere to the respective folding rollers by a holding system comprising either suction holes or mechanical clamps. Then, the downstream portion of each sheet leaves a respective folding roller at the contact line between the two rollers, held by the other folding roller, which is holding already the upstream portion of the previous sheet.
In case of Z or W type interfolding, or even in case of much more folds, as disclosed in U.S. Pat. No. 3,490,762, so-called “multifold”, the interfolding method can be similar to what described above, with the difference that The overlapping step between two successive sheets is carried out immediately after the cut and a stream of partially overlapped sheets reaches the folding rollers from a single direction.
In particular, the folding rollers have a circumference as a multiple to the length of the not overlapped portion of two overlapped sheets. Therefore, the stack of sheets adds an interfolded sheet after each fraction of turn of the folding rollers. This parameter determines the size of the folded sheet being stacked, i.e. the width of the interfolded sheets packages. In view of that, one of the parameters of reference for an interfolding machine is the stack width.
Another reference parameter for an interfolding machine is the length of the sheets, also called cut-off. In particular, in the interfolding machines the length of the interfolded sheets that eventually form the stack of final product is responsive to the circumference of the cutting rollers and to the angular distance among the cutting blades. In other words, the cutting length is fixed and is determined univocally by the circumference of the cutting roller or rollers.
By changing the length of the sheets, or cut-off, it is possible to keep the same pack width, by adjusting the number of interfolded panels.
It can be in particular preferable to adjust the cut-off without changing the pack width, leaving the user a variety of choices for making packs.
A common interfolding machine of “multifold” type allows to produce interfolded sheets of a single length, with an extremely stiff process, and for each sheet length a different machine is required.
In EP 1826165, in the name of the same applicant, an interfolding machine is described multi-fold of modular type, in which it is possible to cut a web of paper into sheets of different length after replacing a modular portion comprising the cutting roller and the transfer roller with another modular portion comprising a cutting roller and a transferring roller of different diameter, and then capable of cutting the web into sheets of different length and causing the sheets to be transferred to an overlapping section.
This solution overcomes the limits of the multi-fold interfolding machines of traditional type, i.e. that of cutting a web of paper into sheets and processing the sheets of a single length.
However, such machines require an area for arranging different modules and involve costs of each modular additional portion and, even if require a relatively quick production change time, they need in any case a maintenance stop.
It is therefore a feature of the present invention to provide a structure of interfolding machine that produces stacks of interfolded sheets allowing a change of production with sheets of different length in order to change easily and quickly between different interfolded configurations.
It is another feature of the present invention to provide an interfolding machine adapted to process sheets of different length that is structurally much easier and cheap with respect to similar interfolding machines of the prior art.
These and other objects are accomplished by the interfolding machine of a web of paper, or similar products, according to the present invention, comprising:
Advantageously, means are provided for selecting alternatively, one among said first cutting, transferring and overlapping means for sheets of a first length and said second cutting, transferring and overlapping means for sheets of a second length.
In particular, said cutting and transferring means cut the web of paper in combination with counter support means acting opposite to said web of paper with respect to said cutting and transferring means to provide said division into said sheets of said first or said second length.
Advantageously, said cutting and transferring means comprises at least one cutting and transferring roller, and said first cutting, transferring and overlapping means for said sheets of a first length comprises a first plurality of blades arranged peripherally on said cutting and transferring roller at a first angular distance and said second cutting, transferring and overlapping means for said sheets of a second length provides a second plurality of blades arranged peripherally on said cutting and transferring roller at a second angular distance, said first and said second plurality of blades being selectively operated for cutting said web into sheets of said first and of said second length, respectively.
Advantageously, said cutting and transferring means comprises, at each of said blades, gripping means of each sheet at least at a respective sheet head that has been formed after cutting.
Advantageously, said cutting and transferring means comprises, furthermore, gripping means of each sheet at least at a portion comprising a respective sheet tail formed after cutting, such that a successive sheet that moves along said conveying path overlaps by said measured portion under a previous sheet whose head has been already gripped by said overlapping means.
Alternatively, said cutting and transferring means comprises:
Advantageously, the cutting and transferring means comprises:
Advantageously, the cutting and transferring means comprises a transfer roller having a plurality of sheet head gripping means arranged peripherally at an angular distance that defines an arch equal to the length of a sheet and that is adapted to transfer to said sheet overlapping roller said sheets of said first and second length, said transfer roller comprising, furthermore, means for gripping and overlapping each sheet at least at a respective sheet tail such that a successive sheet that moves along said conveying path overlaps by said measured portion under a previous sheet whose head has been already gripped by said sheet overlapping roller and whose tail has been held by said means for gripping and overlapping.
In particular, said means for gripping and overlapping the sheets at the respective sheet tail acts only in a determined arch of the transfer roller.
Advantageously, means are provided for adjusting the amplitude of said arch of the transfer roller at which said tail of said sheets is gripped.
In particular, said first plurality of blades and said second plurality of blades can be mounted at respective housings in a way movable selectively between a cutting position, in which said blades protrude from said cutting roller, and a rest position, in which said blades are withdrawn with respect to said cutting roller.
Advantageously, means are provided for actuating said blades between said cutting position and said rest position.
In particular, the means for actuating each blade comprises:
Alternatively, the means for actuating the blades comprises a carriage integral to each blade sliding on a guide, said carriage withdrawing/protruding with respect to the boundary of said roller along said guide for bringing said blade from said cutting position to said rest position, or vice-versa.
Alternatively, said cutting roller has a first plurality of blade holders arranged peripherally on said roller at said first angular distance and a second plurality of blade holders arranged peripherally on said roller at said second angular distance, such that said blades can be mounted on said roller at said first or at said second plurality of blade holders to provide said sheets of said first, or of said second length, respectively.
Furthermore, means are provided for adjusting said actuating means of said cutting and transferring means, said means for adjusting being adapted to change at least one parameter selected from the group comprised of:
a combination thereof.
Advantageously, said first and second plurality of blades have a blade in common.
In particular, the sheet head gripping means are adapted to keep a sheet stuck to the transfer roller for a determined arch.
Advantageously, furthermore, folding means are provided comprising folding rollers, said folding means being adapted to arrange said partially overlapped sheets in a determined interfolded configuration in order to form underneath a stack of interfolded products.
Furthermore, separating means are provided adapted to separate a stack of interfolded sheets from a next stack and to carry it away from the separating area by separating means.
In particular, the cutting means and the sheet head gripping means can be arranged in rows on the respective rollers.
Normally, in an interfolding machine, where the sheets are folded by the folding means according to panels of a same length, so that each sheet has a length that is multiple to the number of panels, being L1 said first length and N1 the number of panels of the sheets of said first length, and being L2 said second length and N2 the number of panels of the sheets of said second length, and being L the length of the panels, so that L1=L*N1, and L2=L*N2, the circumference of the cutting roller and of the transfer roller is identical or multiple to the minimum common multiple between N1 and N2 multiplied by the respective length of the panels, and the first and second cutting, transferring and overlapping means are arranged along the circumference in positions multiple both to N1 and to N2.
An interfolding machine that is made as above described is highly flexible and can provide on a single machine three-panel interfolded sheets, or Z-fold, four-panel interfolded sheets, or W-fold, and six-panel interfolded sheets, wherein the sheet head gripping means and the cutting means provide:
In fact, being twelve the minimum common multiple between three, four and six, by using a roller with a circumference that is multiple to the length of twelve panels, it is possible to arrange the sheet head gripping means and the cutting means at 3,4,6,8,9,12 panels, obtaining the above described angular distances.
Alternatively, in order to provide on a single machine three-panel interfolded sheets and five panel interfolded sheets, the sheet head gripping means provides:
In fact, being fifteen the minimum common multiple between three and five, by using a roller with a circumference that is multiple to the length of fifteen panels, it is possible to arrange the sheet head gripping means and the cutting means at 3,5,6,9,10,12,15 panels, obtaining such angular distance.
Advantageously, the sheet head gripping means can be selected from the group comprised of:
In particular, the transfer roller in addition to the sheet head gripping means and to the sheet tail gripping means has further sheet gripping means at an intermediate sheet point to assist the movement of the sheet on the roller same.
Advantageously, the means for partially overlapping the sheets comprises a sheet overlapping roller adapted to cooperate with the transfer roller. In particular the transfer roller rotates at the first speed whereas the sheet overlapping roller rotates at the second speed in order to deposit on the sheet overlapping roller the overlapped sheets according to a measured fraction.
The holes of the sheet overlapping roller are adapted to grip the head of each sheet. The distance in a circumferential direction between the holes can be equal to two or to one sheet. In particular for a machine that provides one or two panel interfolded sheets, on the sheet overlapping roller four rows of holes rotationally spaced by 90° can be provided, with a distance between the two rows of consecutive holes equal to two panels, whereas for a machine that provides one or two or three-panel interfolded sheets, on the sheet overlapping roller six rows of holes rotationally spaced by 60° can be provided, with a distance between two rows of consecutive holes equal to two panels, and at the same time four rows of holes rotationally spaced by 90°, with a distance between two rows of consecutive holes equal to three panels.
In particular, means can be provided for activating the suction holes of the sheet overlapping roller. For example, two rows of suction holes at 180° can be provided in case of three-panel sheets interfolded by two panels.
Advantageously, each row of suction holes of said transfer roller is in pneumatic connection with a longitudinal duct put in pneumatic connection with a vacuum system and that become active suction holes only at a determined angular field of the transfer roller.
Furthermore, conveying means can be provided adapted to convey the partially overlapped sheets in a position set between the partial overlapping means and the folding rollers.
Further characteristic and the advantages of the interfolding machine, according to the invention, will be made clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings, in which like reference characters designed the same or similar parts, throughout the figures of which:
With reference to
In particular, the web of paper 10 is fed to the cutting and transferring means, comprising, for example, a cutting roller 2 that operates the division of the web 10 into sheets 11 of determined length. The cut sheets, having all the same length, which are carried along the machine are indicated as 11a, 11b, 11c, 11d, 11e, 11f and 11g, starting from the cutting point arranged at the cutting slit 30 of a cutting slit roller 5 fixed, up to the point where they are interfolded.
To this end a transfer roller 3 is provided that conveys sheets 11 to overlapping means, for example to a sheet overlapping roller, also-called “overlap” roller 4.
Up to transfer roller 3, sheets 11 travel along a conveying path at a speed V1, whereas starting from the overlap roller 4, sheets 11 are brought to a second speed V2, with V2 less than V1.
As above described, at first, the cut sheets 11a-11g proceed on transfer roller 3 that rotates at a first speed V1. Then, sheets 11a-11g pass on the sheet overlapping roller 4, or “overlap” roller, which rotates at a second speed V2 less than V1. This speed difference causes sheets 11c and 11d to overlap, since sheet 11c having speed V1 is put below the downstream sheet lid having speed V2 less than V1, which is raised at its tail by the suction of holes 29. The overlapping portion, indicated as 15, of the two sheets 11c and 11d extends for a predetermined number of panels, in order to allow, downstream along the conveying path, the sheets to be interfolded for a desired number of panels, at folding rollers 6 and 7, adapted to make a stack 1.
Between the “overlap” roller 4 and the folding rollers 6 and 7 a conveying systems conveys sheets 11d-11f, partially overlapped, in a corresponding conveying path. In this path, so-called interfolding path, the sheets travel always at the second speed V2 less than V1.
With reference to
In the case shown in
Each blade 21 of cutting roller 2 is associated with gripping means of sheet 11 at the head 11′ thereof. For example, the gripping means of sheet 11 at the head 11′ can comprise a plurality of suction holes 26a-26d for blades 21a-21d and a plurality of suction holes 26′a-26′c for blades 21′a-21′c. The suction holes 26a-26d and 26′a-26′c, in particular grip the head 11′ of sheet 11 which has been obtained with the cut and hold it stuck to roller 2 for an arch set between blade 21, which has caused the cut, which is tangent to transfer roller 3.
Cutting roller 2 works, in fact, in synchronism with transfer roller 3 which has a first and at least a second plurality of gripping means for conveying the head 11′ of sheet 11. Also the gripping means for transferring the sheets can provide a first series of rows of suction holes 27a-27d and a second series of rows of suction holes 27′a-27′c.
In particular, the rows of the suction holes 27a-27d can be arranged on transfer roller 3 at an angular distance from each other equal to 90°, whereas the lines of the suction holes 27′a-27′c can be arranged on transfer roller 3 at an angular distance equal to 120°.
Also concerning the series 27a-27d and 27′a-27′c of suction holes of transfer roller 3, each suction hole 27 is capable of gripping the head 11′ of sheet 11 and keeping it stuck the roller surface of transfer roller 3 only at the arch of circumference 13 which defines an angle ω (
In addition to the series of suction holes 27a-27d and 27′a-27′c, transfer roller 3 has holes 29 that are put in pneumatic connection with a vacuum system, and then in a suction condition, only at a determined angular field 50 having an angular amplitude measured δ of transfer roller 3 same (
In particular, the angular field 50 extends downstream of tangency point with overlap roller 4 and is adapted create suction only in holes 29 of transfer roller 3 arranged in the vicinity of it. This way, the tail 11″d of the downstream sheet 11d is gripped by suction only after that the head 11′d has been gripped by the overlap roller 4. This allows the upstream sheet 11c to slide under sheet 11d, by the speed difference between the rollers 3 and 4. Then, when the hole 29′ that grips by suction the sheet tail has overtaken the angular field 50, it releases sheet 11d that falls partially on sheet 11c obtaining a partially overlapping of the two sheets.
The speed difference V1−V2 determines the length of the overlapping portion, which can be equal to one, two or three panels. This speed difference causes the production a bend 47, immediately starting from the zone that follows the sheet head 11e, and transfer roller 3 has recesses 48 for receiving this bend. The same bend 47 increases progressively and propagates towards the tail of the sheet, as shown for sheet 11f.
More precisely, concerning the operation of the overlapping system, overlap roller 4 rotates at a speed V2, i.e. slower than transfer roller 3. This causes sheet lid, which is transferred by transfer roller 3 to overlap roller 4, owing to vacuum systems 29, 51, 52 shown in
The suction angular field 50 is defined by two fixed tight wings 51 and 52, arranged at an angle. Alternatively, the tight wings can be movable in order to adjust the amplitude of the suction angular field 50, where necessary.
Similarly, cutting roller 2 has a mechanism similar to that described for transfer roller 3 to cause the grip by suction of the sheets on the roller surface only on an arch 155. As shown in
In the exemplary embodiment shown in
As shown in detail in
In an exemplary embodiment of the invention, shown in
As shown in
When blades 21a-21d of the first series are caused to protrude, for example, then web of paper 10 is cut into sheets 11 having the same length as a fourth of the circumference of cutting roller 2 (
The second plurality of cutting blades 21′a-21′c, instead, cuts the web of paper 10 into sheets 11 having a length that is a third of the circumference of cutting roller 2 (
In this case, each sheet 11 is then folded by the interfolding rollers 7 and 8 into four panels I-IV, obtaining a “W” interfolded configuration, with the last two panels III and IV of downstream sheet 11a that is overlapped to panels III and IV of upstream sheet 11b (
A further possibility provided by the present invention is to move to an advanced position only two blades, for example blade 21a and blade 21c of the first series of blades 21a-21d, i.e. arranged at an angular distance of 180° (
In this case, a sheet 11 obtained by cutting the web of paper 2 has a length 13 equal to half the circumference of cutting roller 2, then equal to two times L1. In particular, in order to enable only holes 34a of overlap roller to grip the sheet by suction, whereas holes 34b are excluded, means are provided for activating holes 34, not shown in the figure. Each sheet 11 is then folded by interfolding rollers 7 and 8 into six panels I-VI and the resulting interfolded configuration has the last two panels IV-VI of downstream sheet 11a overlapped to the first two panels I-III of upstream sheet 11b (
For example, the machine, according to the invention, provides an overlapping configuration where three panels are interfolded by one panel (
Normally, with reference to
Always in general, the sheets that have to be folded by the folding rollers according to panels of a same length, would have a length that is multiple to the number of panels. This way, being L1 the first length and N1 the number of panels of the sheets of said first length, and being L2 said second length and N2 the number of panels of the sheets of said second length, and being L the length of the panels, then L1=L*N1, and L2=L*N2. In this case, the circumference of cutting roller 2 is identical or multiple to the minimum common multiple between N1 and N2 multiplied by the respective length L of the panels.
Then, a “multi-fold” machine that has to make selectively three-panel sheets, four-panels sheets and six panel sheets, will have a cutting roller having a diameter at least 12*L, and the blades/suction holes of the head, will have to be selected along the circumference of the roller at positions respectively rotationally distant by a number of panels equal to 3, 4, 6, 8, 9, 12≡0, i.e. with reference to
In this case, blades 21 and/or gripping means 27 of a first plurality are mounted along the boundary of a single cutting and transferring roller 2′, or of two different rollers, i.e. a cutting roller 2 and a transfer roller 3, in positions P1-P4 arranged at a first angular distance φ equal to 90° and blades 21′ and/or the gripping means 27′ of the second plurality are mounted in positions P1′-P3′ arranged at an angular distance ν equal to 120°.
Instead, in a “multi-fold” machine that has to operate selectively sheets three-panel and five-panel sheets, the cutting roller and the transfer roller would have at least a 15*L diameter, and in a way not shown the blades/suction holes of the head, would have to be respectively distant rotationally by a number of panels equal to 0, 3, 5, 9, 10, 12, 15≡0, i.e. with reference to
In this case, blades 21 and/or the gripping means 27 of a first plurality are mounted along the boundary of a single cutting and transferring roller 2′, or of two different rollers, i.e. a cutting roller 2 and a transfer roller 3, in positions P1-P5 arranged at a first angular distance φ equal to 72° and blades 21′ and/or the gripping means 27′ of the second plurality are mounted in positions P1′-P3′ arranged at an angular distance ν equal to 120°.
Alternatively to what above defined, the transfer roller 5 can also be made so that its circumference is multiple to the length L of a sheet. As shown in
The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08156875.0 | May 2008 | EP | regional |
