Patent Application
20240374437
This application claims priority to Italian Patent Application 102023000009093 filed May 8, 2023, the entirety of which is incorporated by reference herein.
This invention relates to a method and a machine for making absorbent sanitary articles such as disposable nappies for adults.
Generally speaking, in the production of absorbent sanitary articles, it is often necessary to apply discrete elements on a continuous web and such discrete elements must be suitably spaced based, for example, on the format or size of the absorbent article.
The absorbent articles concerned comprise, amongst other things, side panels or wings, on the right- and left-hand sides, for closing the nappy around the wearer's waist, which are usually obtained by cutting a continuous web or strip into segments and which are then applied on a continuous support web advancing along a machine direction.
To apply the side panels, prior art machines usually comprise a cutting unit, which receives the continuous web or strip to cut it into the aforesaid right- and left-hand segments, and transfer units located downstream of the cutting unit.
The transfer units pick up or receive the individual segments from the cutting unit, space them along both the machine direction as a function of the length of the absorbent article, and a cross direction transverse to the machine direction as a function of the width of the absorbent article, and apply them to the supporting web so that each right-hand panel has a corresponding left-hand panel.
Documents WO2008/155618 and WO2014/076626 each disclose, for example, a method and a machine for making absorbent articles where, in addition to the above, the pairs of right- and left-hand side wings are arranged beforehand on an alignment roller which applies them on the support web.
The spacing between pairs of panels on the support web depends, as mentioned above, on the size of the absorbent article being made, and the prior art machines either have a very complex way of enabling the right- and left-hand panels to be aligned or placed in phase and suitably spaced in both the machine and cross directions or they necessitate replacement of some of their components when changing over to making an absorbent article of a different size.
Other prior art solutions are described, for example, in U.S. Pat. No. 20,150,24919 and U.S. Pat. No. 6,730,189B1.
The prior art solutions are therefore cumbersome and/or complex and/or costly.
In this context, the intention is to provide a method and a machine for making absorbent sanitary articles and capable of overcoming at least some of the disadvantages of the prior art and of carrying out the aforesaid intention.
In particular, this invention has for an aim to provide a method and a machine for making absorbent sanitary articles which allow discrete elements to be applied on a continuous web and suitably spaced in a simple and inexpensive manner.
This aim is achieved by a method and a machine for making absorbent sanitary articles, comprising the technical features described in one or more of the accompanying claims. The dependent claims correspond to possible different embodiments of the invention.
According to a first aspect, this invention relates to a method for making absorbent sanitary articles, each comprising a first discrete element and a second discrete element.
For example, the absorbent articles may be adult nappies and the first and the second discrete elements may be the right- and left-hand side panels for closing the nappies round the waist.
Nappies for adults are generally characterized by side panels which are approximately half as long as the nappy itself.
The method comprises a step of feeding a succession or series of first discrete elements along a first feed path.
The method comprises a step of feeding a succession or series of second discrete elements along a second feed path.
The method comprises applying each first discrete element of the succession of first discrete elements on a support web which is movable parallel to its own longitudinal axis in a feed direction along a third feed path.
According to the method, the first discrete elements are applied on the support web at a first applicator station.
The method comprises applying each second discrete element of the succession of second discrete elements on the support web at a second applicator station located downstream of the first applicator station in the feed direction of the support web.
The support web may be a single web or a composite web, that is to say, a web comprising two or more components of what will be finished absorbent articles. Generally speaking, the composite web, with the side panels and any other components that may be applied even after the side panels, is then normally cut into separate absorbent articles.
The method comprises adjusting a length of the third feed path between the first applicator station and the second applicator station, so that the second discrete element is applied at a predefined position relative to the first discrete element.
For example, adjusting the length of the third feed path between the first applicator station and the second applicator station is carried out as a function of a predefined application position of the second discrete element relative to the first discrete element along the support web.
The length of the third feed path between the first applicator station and the second applicator station determines the length of the support web between the first applicator station and the second applicator station and can be set, for example, based on a size of the absorbent article.
Preferably, the method comprises cutting a continuous web upstream of the first and the second feed path to make the first discrete elements and the second discrete elements from the continuous web and feeding the first discrete elements to the first feed path and the second discrete elements to the second feed path. Such a configuration is preferably used to make the side panels from a single web, waste free; all the material of the continuous web or strip is used to make the side panels without producing any waste in what is known as a zero-waste application.
For example, the continuous web may be cut by a succession of cuts transverse to a main direction of extension of the continuous web itself to obtain side panels that will be symmetrical relative to the support web when they are applied thereto.
Preferably, the method comprises translating the first discrete elements along the first feed path in a first direction transverse to the first feed path and/or translating the second discrete elements along the second feed path in a second direction transverse to the second feed path. Advantageously, that way, the discrete elements can be positioned, in the cross direction, at a position suitable for them to be applied to the support web.
The method may comprise accelerating the first discrete elements along the first feed path and/or accelerating the second discrete elements along the second feed path to bring them to an application speed suitable for them to be applied to the support web moving along the respective feed path.
Preferably, the method comprises holding the first discrete elements on the support web by suction at least between the first applicator station and the second applicator station.
Preferably, the first and the second discrete element are applied on the support web in such a way that each second discrete element is symmetrical to a corresponding first discrete element about the longitudinal axis of the support web so they belong to the same absorbent article once the composite web, as mentioned above, is cut into separate absorbent articles.
Preferably, the method is advantageously applicable when the sum of the length of the first discrete element, measured along the support web, and the length of the second discrete element, measured along the support web, is different from the length of the absorbent sanitary article, measured along the support web. In particular, the method is advantageous for applying the side panels of the absorbent article when the total length of the right-hand panel and of the left-hand panel is different from the length of the absorbent article.
According to an aspect, this invention relates to a machine for making absorbent sanitary articles.
Preferably, the machine implements the method of the first aspect to which express reference will also be made without losing in generality.
The machine comprises a first transfer unit at least partly defining a first feed path for a succession of first discrete elements movable along the first feed path. Preferably, the first transfer unit rotates about a first axis of rotation transverse to the first feed path.
The machine comprises a second transfer unit at least partly defining a second feed path for a succession of second discrete elements movable along the second feed path. Preferably, the second transfer unit rotates about a second axis of rotation transverse to the second feed path.
The machine comprises a first applicator station located downstream of the first transfer unit along the first feed path for applying each first discrete element of the succession of first discrete elements on a support web movable in a feed direction along the third feed path.
The machine comprises a second applicator station, located downstream of the first applicator station along the feed path of the support web and downstream of the second transfer unit along the second feed path, for applying each second discrete element of the succession of second discrete elements on the support web.
The machine comprises an adjustment device for adjusting the third feed path between the first applicator station and the second applicator station. The adjustment device at least partly defines the third feed path and is configured to adjust a length of the third feed path between the first applicator station and the second applicator station, so that the second discrete element is applied at a predefined position relative to the first discrete element.
The length of the third feed path between the first applicator station and the second applicator station determines the length of the support web between the first applicator station and the second applicator station and can be set, for example, based on a size of the absorbent article.
The adjustment device may comprise, for example, a first rotary drum at the first applicator station, a second rotary drum at the second applicator station and at least one adjustment drum, interposed between the first and the second rotary drum, for adjusting the third feed path.
The drums of the adjustment device have parallel axes of rotation transverse to the third feed path.
The adjustment drum is movable relative to the first rotary drum and to the second rotary drum between a first operating position and a second operating position corresponding respectively to a maximum length of the third feed path between the first applicator station and the second applicator station, and a minimum length of the third feed path between the first applicator station and the second applicator station.
For example, at the first operating position, the adjustment drum is away from the first and the second rotary drum, whilst at the second operating position, it is close to them.
Preferably, the first rotary drum, the second rotary drum and the adjustment drum are provided with suction means to hold the support web and to hold the first and second discrete elements in place on the support web.
The machine may comprise, between the first rotary drum and the adjustment drum, a first suction box which delimits a first stretch of the third feed path.
The machine may comprise, between the adjustment drum and the second rotary drum, a second suction box which delimits a second stretch of the third feed path.
The whole of the third feed path between the first applicator station and the second applicator station is provided with suction for holding the first discrete element and/or the second discrete element on the support web.
The machine may comprise a cutting unit, located upstream of the first and the second transfer unit for cutting a continuous web upstream of the first and the second feed path to make the first discrete elements and the second discrete elements from the continuous web.
The cutting unit and the first and second transfer units may be positioned relative to each other in such a way that the cutting unit feeds the first discrete elements to the first feed path and the second discrete elements to the second feed path.
Preferably, the first transfer unit comprises at least a first working unit movable along a first direction transverse to the first feed path for moving the first discrete element. The first transfer unit is configured so that the first movable working unit moves the first discrete element in translation along the first transverse direction in a substantially known manner.
Preferably, the second transfer unit comprises at least a second working unit movable along a second direction transverse to the second feed path for moving the second discrete element. The second transfer unit is configured so that the second movable working unit moves the second discrete element in translation along the second transverse direction in a substantially known manner.
The movable working units of the first and second transfer units adjust the position of the first and second discrete elements in a direction transverse to the feed paths.
The movable working units of the first and second transfer units adjust the position of the first and second discrete elements in a direction transverse to the machine direction, that is to say, they position the first and second discrete elements in the cross direction.
Preferably, the machine comprises a first acceleration unit, located downstream of the first transfer unit and upstream of the first applicator station along the first feed path for adjusting a transfer speed of the first discrete elements before they are applied on the support web.
In practice, preferably, as they advance towards the first applicator station, the first discrete elements are formed in the cutting station, suitably positioned in the cross direction on the first transfer wheel and accelerated to the application speed by the first acceleration unit.
Preferably, the machine comprises a second acceleration unit, located downstream of the second transfer unit and upstream of the second applicator station along the second feed path for adjusting a transfer speed of the second discrete elements before they are applied on the support web.
In practice, preferably, as they advance towards the second applicator station, the second discrete elements are formed in the cutting station, suitably positioned in the cross direction on the second transfer wheel and accelerated to the application speed by the second acceleration unit.
The machine for making absorbent sanitary articles is simple and lightweight, in particular because in the specific case of applying the side panels, the right-hand panel and the left-hand panel are placed in phase by a device as simple as a path regulator.
The layout of the machine is also simple, without particularly complex wheel systems to manage acceleration and phasing, for example. Maintenance, when required, is also easy in that all the units are easy to access.
Moving the discrete elements on suction drums and/or along suction paths makes it easier for the panels to not be disarranged, in particular in the case where the adjustment path defined between the first and the second applicator station is provided with uninterrupted suction.
In a preferred example, any changes to the path of the support web can be made by moving the adjustment drum.
When changing over to a different size, the setting of the adjustment drum changes; the position of the adjustment drum is chosen, in particular, to define the placement position where the second discrete element is placed on the support web as a function of the size.
The second applicator station may be followed by an outfeed conveyor for transferring the support web provided with the first and second discrete elements to the processing stations downstream.
The method and machine according to the aforesaid aspects are particularly advantageous when the discrete elements to be applied to the support web are large relative to the product to be made. In particular, varying the length of the web between the application of the first discrete element and the application of the second discrete element avoids having to construct complex machines to position and also phase the discrete elements, that is to say, it avoids the need for otherwise very complex laws of motion.
Further features and advantages of the above aspects are more apparent in the exemplary, hence non-limiting description of a method and a machine for applying web segments to a continuous web.
The description is set out below with reference to the accompanying drawings which are provided solely for purposes of illustration without restricting the scope of the invention and in which:
With reference to
The support web W may be a composite web, that is, a web comprising a plurality of pre-assembled components and also for this reason, the web provided with the discrete elements A and B is also denoted by the same reference character W.
The web W is, in practice, a semifinished product from which the absorbent sanitary articles will be made.
The machine 1 may form part of a plant, not illustrated, for the production of absorbent sanitary articles in which the machine 1 carries out intermediate steps of a complete process for the production of absorbent sanitary articles.
The first and the second discrete element A and/or B may be, for example, side panels of the absorbent article for closing the article round the waist, web segments with desired properties, such as an acquisition and distribution layer (ADL), applied to the absorbent article, an impermeable web segment or a comfort enhancing web segment for the absorbent article.
In this disclosure, express reference is made, without thereby losing in generality, to an absorbent article comprising a first and a second discrete element A and B constituting, respectively, a side panel A and a side panel B which will form part of a closing system allowing the absorbent sanitary article to be closed round the waist of a wearer, not illustrated.
In particular, express reference will also be made to a machine for making adult nappies comprising the first and second side panels A and B.
Adult nappies are, for example, between 800 mm and 1000 mm long, with side panels between 400 mm and 500 mm long; that is to say, the side panels are very large in relation to the maximum length of the absorbent sanitary article. It should be considered, for example, that the side wings of a baby nappy, which is between 300 mm and 600 mm in length, are between 50 mm and 80 mm long.
With reference in particular to
The feed direction of the side panels A and B along the respective feed paths PA and PB, from left to right looking, in particular, at
As illustrated, for example, in
The cutting unit 2, of substantially known type, is represented schematically as two counter-rotating rollers 2a, 2b, where, for example, one roller 2a comprises a cutting edge and the other, 2b, constitutes an anvil.
The cutting unit 2 is positioned relative to the paths PA and PB in such a way that the cutting unit 2 feeds the discrete elements A to the feed path PA and the discrete elements B to the feed path PB.
The machine 1 comprises a transfer unit 3 for transferring the discrete elements A and which at least partly defines the feed path PA.
In the example illustrated, the transfer unit 3 rotates anticlockwise about an axis of rotation R3 transverse to the feed path PA.
The transfer unit 3 comprises a plurality of working units 4, movable along a direction which is transverse to the feed path PA and preferably parallel to the axis R3.
The working units 4 are movable along the axis R3 between a pickup point 4A and a release point 4B.
The working units 4 move the discrete elements A in translation in an axial direction between the pickup position 4A and the release position 4B as they advance along the path PA.
During a rotation of the transfer unit 3, the side panels A are picked up at the position 4A and released at the position 4B.
The movable working units 4 of the transfer unit 3 adjust the position of the discrete elements A in a cross direction transverse to the machine direction.
The machine 1 comprises an acceleration unit 5, located downstream of the transfer unit 3 along the feed path PA.
The acceleration unit 5 adjusts the transfer speed of the discrete elements A before they are applied on the support web W.
In the example illustrated, the acceleration unit 5 comprises three working units 6 which oscillate about an axis of rotation R6 to transfer the discrete elements A from the transfer unit 3 to an applicator station 7, where the discrete elements A are applied on the support web W.
A glue dispenser, schematically represented as a block 13A, is configured to dispense adhesive on the web W before the side panels A are applied.
Preferably, the discrete elements A are held on the transfer unit 3 and on the oscillating working units 6 by suction in a substantially known manner.
The applicator station 7 is located downstream of the transfer unit 3 along the feed path PA.
As they advance towards the applicator station 7, the discrete elements A are formed in the cutting station 2, suitably positioned in the cross direction on the transfer wheel 3 and accelerated to the application speed by the acceleration unit 5.
The acceleration unit 5 can also modify the spacing of the discrete elements A in the succession SA, that is to say, the distance between consecutive discrete elements A, to obtain the spacing at which the discrete elements A are applied on the support web W.
The machine 1 comprises a transfer unit 8 for transferring the discrete elements B and which at least partly defines the feed path PB.
In the example illustrated, the transfer unit 8 rotates anticlockwise about an axis of rotation R8 transverse to the feed path PB.
The transfer unit 8 comprises a plurality of working units 9, movable along a direction which is transverse to the feed path PB and preferably parallel to the axis R8.
The working units 9 are movable along the axis R8 between a pickup point 9A and a release point 9B.
The working units 9 move the discrete elements B in translation in an axial direction between the pickup position 9A and the release position 9B as they advance along the path PB.
During a rotation of the transfer unit 8, the side panels B are picked up at the position 9A and released at the position 9B.
The movable working units 9 of the transfer unit 8 adjust the position of the discrete elements A in a cross direction transverse to the machine direction.
The machine 1 comprises an acceleration unit 10, located downstream of the transfer unit 8 along the feed path PB.
The acceleration unit 10 adjusts the transfer speed of the discrete elements B before they are applied on the support web W.
In the example illustrated, the acceleration unit 10 comprises three working units 11 which oscillate about an axis of rotation R11 to transfer the discrete elements B from the transfer unit 8 to an applicator station 12, where the discrete elements B are applied on the support web W.
Preferably, the discrete elements B are held on the transfer unit 8 and on the oscillating working units 11 by suction in a substantially known manner.
The applicator station 12 is located downstream of the transfer unit 8 along the feed path PB.
The applicator station 12 is located downstream of the applicator station 7 along the feed path PW of the web W; that is to say, the discrete elements B are applied on the web W after the discrete elements A.
A glue dispenser, schematically represented as a block 13B, is configured to dispense adhesive on the web W before the side panels B are applied.
As they advance towards the applicator station 12, the discrete elements B are formed in the cutting station 2, suitably positioned in the cross direction on the transfer wheel 8 and accelerated to the application speed by the acceleration unit 10.
The acceleration unit 10 can also modify the spacing of the discrete elements B in the succession B, that is to say, the distance between consecutive discrete elements B, to obtain the spacing at which the discrete elements B are applied on the support web W.
The machine comprises an adjustment device 14 for adjusting the feed path PW of the support web W between the applicator station 7 and the applicator station 12.
The adjustment device 14 at least partly defines the feed path PW and is configured to adjust the length of the feed path PW between the applicator station 7 and the applicator station 12 so that the discrete element B is applied at a predefined position relative to the discrete element A.
For example, the adjustment device 14 allows adjusting the length of the feed path PW between the applicator station 7 and the applicator station 12 as a function of a predefined application position of the discrete element B relative to the discrete element A on the support web W.
The length of the feed path PW between the applicator station 7 and the applicator station 12 determines the length of the support web W between the applicator station 7 and the applicator station 12 and can be set, for example, based on a size of the absorbent article.
Adjusting the length of the feed path PW between the applicator station 7 and the applicator station 12 determines the application position of the discrete elements B so that each discrete element B is positioned symmetrically to a corresponding discrete element A.
In the example illustrated, the adjustment device 14 comprises a rotary drum 15 which is rotatable about an axis of rotation R15 in anticlockwise direction.
The rotary drum 15 is located at the applicator station 7.
The rotary drum 15 defines the applicator station 7 in cooperation with the acceleration unit 5.
The adjustment device 14 comprises a rotary drum 16 which is rotatable about an axis of rotation R16 in anticlockwise direction.
The rotary drum 16 is located at the applicator station 12.
The rotary drum 16 defines the applicator station 12 in cooperation with the acceleration unit 10.
Preferably, the axes of rotation R15 and R16 are parallel to each other and parallel to the axes of rotation R3, R6, R8 and R11.
The adjustment device 14 comprises an adjustment drum 17 interposed between the rotary drums 15 and 16 and rotatable about an axis of rotation R17.
The axis of rotation R17 is preferably parallel to the axes of rotation R15 and R16 and transverse to the path PW.
The adjustment drum 17 is movable between a first operating position, illustrated for example in
At the first operating position, the adjustment drum 14 determines a maximum length of the feed path PW between the applicator station 7 and the applicator station 12.
At the second operating position, the adjustment drum 14 determines a minimum length of the feed path PW between the applicator station 7 and the applicator station 12.
The adjustment drum 17 is movable between the first and the second operating position relative to the rotary drum 15 and to the rotary drum 16.
The web W is partly wrapped round the adjustment drum 15, the adjustment drum 17 and the adjustment drum 16 and moving the adjustment drum 17 causes, in particular, the two branches 18, 19 of the feed path PW between the applicator station 7 and the applicator station 12 to be lengthened or shortened.
Shown represented on the right-hand side of
The length of the branches 18 and 19 depends on the position of the adjustment drum 17.
Adjusting the position of the adjustment drum 17 allows aligning the panels A and B on the web W, upstream, as they enter the transfer units 3 and 8, out of phase, that is, behind one another, as made by the cutting unit 2.
The machine 1 uses the acceleration units 5 and 10 to feed the discrete elements A and B so that their placement speed is consistent with the speed of the support web W and uses the adjustment device 14 to phase each discrete element A with a corresponding discrete element B on the web W.
The position of the adjustment drum 17 is chosen, for example, as a function of the size of the absorbent article.
The rotary drum 15, the rotary drum 16 and the adjustment drum 17 are provided with suction means to hold the support web W and to hold the discrete elements A and B on the support web W.
In the embodiment illustrated, the machine 1 comprises, between the rotary drum 15 and the adjustment drum 17, a suction box 20 at the stretch 18 of the feed path PW.
The machine 1 comprises, between the adjustment drum 17 and the rotary drum 16, a suction box 21 at the stretch 19 of the feed path PW.
Thus, the whole of the feed path between the applicator station 7 and the applicator station 12 is provided with suction for holding the side panel A and/or the side panel B on the support web PW, preventing them from being disarranged.
The suction boxes 20, 21 are configured to allow the adjustment drum 17 to move while ensuring that the stretches 18 and 19 are provided with suction whatever the position of the adjustment drum 17.
In the embodiment illustrated, the machine 1 comprises an outfeed conveyor 22 for transferring the support web W provided with the discrete elements A and B to the processing stations downstream, not illustrated.
Described below is a method for making absorbent sanitary articles, each comprising a discrete element A and a discrete element B, suitably positioned relative to each other. For convenience, the method is described with reference also to a machine like that illustrated in
With reference to
The method comprises feeding a succession or series SA of discrete elements A along the feed path PA and feeding a succession or series SB of discrete elements B along the feed path P.
The method comprises applying each discrete element A of the succession SA on the support web W, which is movable parallel to its own longitudinal axis in the feed direction VW along the feed path PW. According to the method, the discrete elements A are applied on the support web W in the applicator station 7.
The method comprises applying each discrete element B of the succession SB of discrete elements B on the support web W in the second applicator station 12, located downstream of the applicator station 7 in the feed direction VW of the support web W.
The method comprises adjusting a length of the feed path PW between the applicator station 7 and the applicator station 12 so that the discrete element B is applied at a predefined position relative to the discrete element A.
The discrete elements A and B are applied on the support web W in such a way that each discrete element B is symmetric to a corresponding discrete element A about the longitudinal axis of the support web W.
Each discrete element or side panel A and the one symmetric to it B belong to the same absorbent article when the composite web W is cut into distinct absorbent articles.
The method comprises cutting the continuous web AB upstream of the feed paths PA, PB to make the discrete elements A, B and feeding the discrete elements A to the feed path PA and the discrete elements B to the feed path PB.
The continuous web AB is preferably cut by a succession of cuts transverse to a main direction of extension of the continuous web AB itself so as to obtain identical side panels A, B that will be positioned symmetrically along the support web W.
The method comprises moving the discrete elements A in translation along the feed path PA and/or moving the discrete elements B in translation along the feed path PB in the cross direction to place them at a position suitable for them to be applied on the support web W. The method comprises accelerating the discrete elements A along the feed path PA and/or accelerating the discrete elements B along the feed path PB in the cross direction to place them at a position suitable for them to be applied on the support web W.
The method comprises holding the discrete elements A on the support web W by suction at least between the applicator station 7 and the applicator station 12 so that they are not disarranged as the web W moves.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102023000009093 | May 2023 | IT | national |
