Roll changer for an apparatus for producing hygienic products

Information

  • Patent Grant
  • 6578616
  • Patent Number
    6,578,616
  • Date Filed
    Friday, March 9, 2001
    23 years ago
  • Date Issued
    Tuesday, June 17, 2003
    21 years ago
Abstract
A roll changer for splicing starting piece and end pieces of material webs to each other in an apparatus for producing hygienic products, includes carriers for web rolls, holding and guiding elements, severing elements and embossing rolls. The starting piece of a new material web can be fixed to an embossing roll. At least one embossing roll can be driven and at least one embossing roll can be moved selectively toward and away from the other embossing roll.
Description




FIELD OF INVENTION




The invention relates to a roll changer for splicing starting pieces and end pieces of material webs in an apparatus for producing hygienic products.




BACKGROUND INFORMATION




A method and an apparatus of the type of interest here are known in principle from EP 0 525 075 B1. This document describes a method and an apparatus for splicing at least two materials containing two single-ply or multi-ply, air permeable and soft paper webs. The material webs are joined by being spliced in the nip of two embossing rolls. The starting piece of the material web to be joined is initially held with the aid of a suction box, whose holding force is canceled when the web is to be joined to the end of piece of the other web.




The problem with the known apparatus is that it is necessary to operate there with a very accurately defined vacuum. Controlling the vacuum is therefore difficult. In addition, the fact that the end piece of one web has to pull the starting piece of the web to be joined to it is not without problems, although both webs, before entering the nip of the embossing rolls, are sucked against a suction box by vacuum.




SUMMARY OF THE INVENTION




The invention is therefore based on the object of providing the conditions for the most simple and quick roll change which may be carried out with only little effort.




In order to achieve this object, the invention provides, in a roll changer for splicing a starting piece to an end piece of successive material webs, for the starting piece of a new material web to be capable of being fixed to an embossing roll, and for at least one embossing roll to be capable of being driven and for at least one embossing roll to be capable of being moved toward the other embossing roll and away from it.




During production, the unwinding material web moves through the embossing nip without touching an embossing roll. Both embossing rolls are therefore stopped during production. According to the invention, the starting piece of the material web to be joined is fixed directly to one of the two stationary embossing rolls. For this purpose, both embossing rolls preferably have a suction strip or a row of suction openings and can be connected to vacuum lines.




In order to splice the materials webs, the two embossing rolls are pressed against each other and set rotating. In the process, the two material webs are joined by pressure and deformation in the manner of a splice, the end piece of one material web then being severed following the production of the splice.




The aforesaid measures can be prepared easily. The actual splicing operation can then be carried out securely and reliably. This results in a rapid roll change with a short transition from the end of one material web to the start of the next material web.











BRIEF DESCRIPTION OF THE DRAWINGS




The invention will be described in more detail below using an exemplary embodiment which is illustrated in the drawing, in which:





FIG. 1

shows a basic sketch of essential parts of the roll changer and the apparatus belonging to it;





FIG. 2

shows a detail from

FIG. 1

on an enlarged scale;





FIG. 3

shows an end view of the two embossing rolls on a further enlarged scale, and





FIG. 4

shows a view similar to that of

FIG. 2

during the splicing operation.











DETAILED DESCRIPTION OF A PREFERRED EXAMPLE EMBODIMENT OF THE INVENTION




A roll changer


1


for splicing a starting piece


2


of a material web


3


to an end piece


4


of another material web


5


in an apparatus


6


for producing hygienic products comprises carriers


7


and


8


for web rolls


9


and


10


and embossing rolls


11


and


12


, with the aid of which the starting piece


2


is pressed onto the end piece


4


during a passage through a nip


40


between the two embossing rolls


11


and


12


. The two embossing rolls


11


,


12


have free-rotation devices (not illustrated) such that the embossing roll


11


can be rotated only the direction of the arrow


24


and the embossing roll


12


can be rotated only in the direction of the arrow


25


. By means of suitable non-return blocking means, the embossing roll


11


can therefore be rotated only in the clockwise direction in FIG.


2


and the embossing roll


12


can be rotated only in the counterclockwise direction.




One embossing roll


11


can be moved toward the other embossing roll


12


and away from it. To this end, the embossing roll


11


is mounted on a carrier


13


and, together with the carrier


13


, can be pivoted about an axis


14


. A controllable drive


15


is used to adjust and to fix the carrier


13


in the pressing and splicing position of the embossing roll


11


(FIG.


2


).




The other embossing roll


12


is mounted in a stationary position. In addition, the embossing roll


12


is assigned a drive


15


′, with the aid of which it is possible not only to set the embossing roll


12


rotating positively, but also the embossing roll


11


pressed in the direction of the embossing roll


12


during the splicing of the material webs


3


and


5


. The driven embossing roll


12


drives the not self-driven embossing roll


11


with it during splicing, on account of a frictional connection.




The two embossing rolls


11


and


12


are illustrated on an enlarged scale in FIG.


3


and reveal that each embossing roll


11


,


12


has a holding element


16


for the starting piece of a material web. According to the exemplary embodiment, the holding element


16


is a suction strip or comprises a row of suction openings


16


′, which are each arranged on the circumference


17


, parallel to the axis


18


of each embossing roll


11


,


12


, In each case via a suction duct


19


having a control window at a front end of each embossing roll


11


,


12


, an air-carrying connection to a suction and control duct


20


is also provided, said duct extending in an arc along the movement path of the suction duct


19


or control window in a stationary control disk arranged at one end beside the embossing roll. The suction and control ducts


20


in the two control disks are oriented toward each other, according to

FIG. 3

, and each extend over about 90° and end at the same height, approximately on a connecting line


21


between the two axes


18


.




In addition, the two arcuate suction and control ducts


20


are each connected to a vacuum line


22


which, depending on the operating state, supplies neither or one or the other embossing roll


11


,


12


with vacuum in the area of the suction openings


16


′.




The roll changer


1


further comprises holding and guiding elements


30


and


31


which, firstly, act during normal operation and, secondly, act during the preparation and production of a splice. They are mounted such that they can each be pivoted about an axis


32


and


33


, respectively, with the aid of drives


34


,


35


, and are arranged substantially symmetrically in relation to the two embossing rolls


11


,


12


. The holding and guiding elements


30


,


31


each have a guide face


39


and can be moved into a position in which the guide face


39


lies in a plane that is tangential to the two embossing rolls


11


,


12


.




On its circumference, each holding and guiding element


30


,


31


has at least one deflection element


26


and


36


and, according to the exemplary embodiment, in each case two deflection elements


26


,


27


and


36


,


37


for the respective material web


3


and


5


. Together with the pivot axes


32


,


33


and the deflection elements


26


,


27


and


36


,


37


, the holding and guiding elements


31


,


32


in each case form approximately triangles.




According to the illustration in

FIG. 2

, the material web


5


is used for the production of parts. The continuously unwinding material web


5


is led over the holding and guiding element


31


, which in this case is pivoted up. The material web


5


runs from a deflection element


41


which is arranged in a stationary position to the deflection elements


26


and


27


on the circumference of the holding and guiding element


31


and then, without contact, through the nip


40


to further deflection elements


42


and


43


and so on. The operating position of the holding and guiding element


31


with its deflection elements


26


upstream of the nip


40


, and the position of the deflection element


42


downstream of the nip


40


are in principle selected such that the normal, operational passage of the material web


5


is carried out without any contact with the embossing rolls


11


or


12


.




During production with the material web


5


, the embossing roll


11


is moved out of its embossing position (in the counterclockwise direction in

FIG. 2

) in order to produce the widest possible embossing roll gap


40


, and is also moved away from the embossing roll


12


. The material web


5


therefore runs between the deflection element


26


and the deflection element


42


without contact through the opened embossing roll gap


40


. At the same time, the holding and guiding element


30


is pivoted so that its guide face


39


is brought into a horizontal position (

FIG. 2

) in order to prepare the next splicing operation with the starting piece


2


of the material web


3


.




The new material web


3


is pulled with its starting piece


2


over the deflection elements


38


and


36


in order to prepare a splicing operation, and fixed to the embossing roll


11


with the aid of the holding element


16


or the suction openings


16


′. To this end, the suction openings


16


′ on the embossing roll


11


have vacuum applied to them, while the suction air on the embossing roll


12


remains switched off.




The embossing roll


11


is then rotated onward in the clockwise direction or in the direction of the arrow


24


by about 90°, until the starting piece


2


is placed securely in the opened embossing roll gap


40


.




Then, the holding and guiding element


30


is pivoted up, with the aid of the drive


34


, into an unwinding position (FIG.


2


). By means of the freewheel integrated in the embossing roll


11


, the embossing roll


11


is prevented from rotating back. At the same time, the material web


3


is pulled off from the web roll


9


.




The embossing roll


11


is then moved in the direction of the embossing roll


12


with the aid of the drive


15


, the starting piece


2


of the material web


3


being pressed against the material web


5


. At the same time, the embossing roll


12


is set rotating in the direction of the arrow


25


with the aid of its drive


15


′, the embossing roll


11


being co-rotated in the direction of the arrow


24


and the material webs


3


and


5


being embossed with each other. Directly after the start of the rotation of the embossing roll


11


, the vacuum prevailing at its suction openings


16


′ is interrupted and, at the holding and guiding element


31


, the end piece


4


is severed from the remainder


44


of the material web


5


with the aid of a severing element


45


. Also provided, in addition to the severing element


45


, are devices


46


for holding the material web during the severing cut.




As soon as the end piece


4


has been embossed with the new material web


3


, the embossing roll


11


is removed from the embossing roll


12


again, so that a wide embossing roll gap


40


is produced between them. At the same time, the drive


15


′ is stopped. The new material web


3


then runs between the deflection elements


36


and


42


without contact through the gap


40


.




The holding and guiding element


31


is subsequently pivoted back into its horizontal position, and therefore clears the way for the preparation of a new web roll


10


, whose web start is joined to the web end of the material web


3


in the same way by embossing when this web has been processed.




In accordance with the different requirements, the two holding and guiding elements


30


and


31


are located in different positions and — as referred to the plane defined by the embossing nip


40


—can be moved toward each other and away from each other. During operation, one holding and guiding element


31


is substantially vertical, while the other holding and guiding element is pivoted into an approximately horizontal position.




The deflection elements


36


to


38


can in each case be deflection rollers, just like the other deflection elements


41


to


43


.




The material web is supplied to the production apparatus


6


via a tensioning device


47


, which is known in principle and has a deflection roller


48


.



Claims
  • 1. A roll changer for splicing starting pieces (2) and end pieces (4) of material webs (3, 5) to each other in an apparatus (6) for producing hygienic products, comprising carriers (7, 8) for web rolls (9, 10), holding and guiding elements (30, 31), severing elements (45) and embossing rolls (11, 12), wherein the starting piece (2) of a new material web (3) can be fixed to an embossing roll (11 or 12), wherein at least one embossing roll (12) can be driven and at least one embossing roll (11) can be moved toward the other embossing roll (12) and away from it, and wherein the holding and guiding elements (30, 31) each have a guide face (39) and can be moved into a position in which the guide face (39) lies in a plane that is tangential to the two embossing rolls (11, 12).
  • 2. The roll changer as claimed in claim 1, wherein two of the holding and guiding elements (30, 31), which are mounted such that they can move, are arranged upstream of the embossing rolls (11, 12) in the running direction of the material webs (3, 5).
  • 3. The roll changer as claimed in claim 2, wherein the two holding and guiding elements (30, 31) are arranged symmetrically with regard to the two embossing rolls (11, 12).
  • 4. The roll changer as claimed in claim 2, wherein the two holding and guiding elements (30, 31) can be pivoted about axes (32, 33).
  • 5. The roll changer as claimed in claim 1, wherein each embossing roll (11, 12) has a holding element (16) for the starting piece (2) of a material web (3).
  • 6. The roll changer as claimed in claim 5, wherein the holding element (16) provided is at least one suction strip or a row of suction openings (16′) and can be connected to a vacuum line (22).
  • 7. The roll changer as claimed in claim 1, wherein at least one of the holding and guiding elements (30, 31) has a device (46) for holding the material web (3, 5) during a severing cut.
  • 8. The roll changer as claimed in claim 1, wherein each holding and guiding element (30, 31) has at least one deflection element (36, 37) on its circumference.
  • 9. The roll changer as claimed in claim 8, wherein each holding and guiding element (30, 31) has two deflection elements (26, 27 and 36, 37) which, together with a pivot axis (32, 33) of the holding and guiding element (30, 31), form a triangle.
  • 10. The roll changer as claimed in claim 9, wherein a respective severing element (45) is arranged between the two deflection elements (26, 27 and 36, 37) of each holding and guiding element.
  • 11. The roll changer as claimed in claim 8, wherein the deflection element (36, 37) is a deflection roller.
  • 12. The roll changer as claimed in claim 1, wherein the holding and guiding elements (30, 31) can be moved toward each other and away from each other relative to a plane defined by a nip (40) between the embossing rolls.
  • 13. The roll changer as claimed in claim 1, wherein each one of the holding and guiding elements (30, 31), when in operation, leads the material web (3, 5) through an embossing roll gap (40) between the embossing rolls without contact.
  • 14. The roll changer as claimed in claim 13, wherein a deflection element (42) is assigned to both embossing rolls (11, 12), and the holding and guiding elements (30, 31) can be moved and fixed, both in such a way that an unwinding material web (5) touches neither of the two embossing rolls (11, 12).
  • 15. The roll changer as claimed in claim 1, wherein the guide face (39) of a respective one of the holding and guiding elements (30, 31) is located in a horizontal position when the new material web (3, 5) is being fixed to a respective one of the embossing rolls (11, 12).
Priority Claims (1)
Number Date Country Kind
100 12 000 Mar 2000 DE
US Referenced Citations (6)
Number Name Date Kind
3841944 Harris, Jr. Oct 1974 A
4100012 Meihofer et al. Jul 1978 A
4219378 Marschke Aug 1980 A
5360502 Andersson Nov 1994 A
5427639 Minarelli Jun 1995 A
5443681 Stivani et al. Aug 1995 A