US-12617644-B2 - Suction roll of a web, or sheet, of paper in a paper converting machine

US12617644B2US 12617644 B2US12617644 B2US 12617644B2US-12617644-B2

Abstract

A suction roll of a web, or sheet, of paper, includes a tubular body that rotates about a longitudinal rotation axis. External and internal lateral surfaces of the suction roll pneumatically communicate with each other through suction holes. The roll includes a suction chamber pneumatically connected to a vacuum generation device for generating a predetermined vacuum degree. A vacuum distribution device selectively puts into pneumatic communication the suction chamber with at least one row of suction holes, at determined angular positions of the tubular body and causes the processed sheet or web of paper to be sucked, and to adhere at a corresponding portion of the external lateral surface arranged between a catching point and a releasing point having determined angular positions. A displacement device moves the vacuum distribution device to change the angular position of the catching or releasing point of the web or sheet of paper.

Inventors

SERGIO LOMBARDI
DANIELE DAMIANI

Assignees

KÖRBER TISSUE FOLD S.R.L.

Dates

Publication Date: 20260505
Application Date: 20211119
Priority Date: 20201120

Claims (17)

1 . A suction roll of a web, or sheet, of paper, fed along an advancing direction in a paper converting machine, or similar products, said suction roll comprising: a tubular body configured to rotate about a longitudinal rotation axis in a predetermined sense of rotation, said tubular body being provided with an external lateral surface and with an internal lateral surface communicating with each other through a plurality of suction holes organized according to a plurality of longitudinal rows; a suction chamber defined within said suction roll and pneumatically connected to a vacuum generation device configured to generate a predetermined vacuum degree; a vacuum distribution device configured to selectively put into pneumatic communication said suction chamber with at least one row of suction holes of said plurality, at determined angular positions of said tubular body, and to cause the processed sheet or web of paper to be sucked, and to adhere at a corresponding portion of said external lateral surface of said suction roll arranged between a catching point and a releasing point (P1,P2) having determined angular positions; and a displacement device configured to move said vacuum distribution device in such a way to change the angular position of said catching point and/or of said releasing point of said web or sheet of paper, and, therefore, to anticipate, or postpone, the catching instant and/or the releasing instant) where said web or sheet of paper adheres to, or leaves said external lateral surface of said suction roll; wherein said displacement device is configured to move said vacuum distribution device during said rotation of said tubular body about said longitudinal rotation axis, in such a way to progressively follow the increase or decrease of the advancement speed of the web or sheet of paper.
2 . The suction roll of a web, or sheet, of paper, according to claim 1 , wherein: said vacuum distribution device comprises a fixed tubular body coaxially mounted within said tubular body, said fixed tubular body being pneumatically connected to said device for generating a predetermined vacuum degree and being provided with at least one aperture; and said displacement device is configured to cause a rotation of said fixed tubular body about said longitudinal rotation axis.
3 . The suction roll of a web, or sheet, of paper, according to claim 2 , wherein said displacement device is arranged to engage said fixed tubular body at least at an engagement portion axially protruding from an end of said tubular body.
4 . The suction roll of a web, or sheet, of paper, according to claim 1 , wherein said displacement device comprises an actuation device.
5 . The suction roll of a web, or sheet, of paper, according to claim 4 , wherein said actuation device is an electric actuator, or a pneumatic actuator, or combination thereof.
6 . The suction roll of a web, or sheet, of paper, according to claim 4 , wherein said actuation device is configured to be operated on the basis of a command given by an operator through an interface panel, or Human Machine Interface.
7 . The suction roll of a web, or sheet, of paper, according to claim 3 , wherein said actuation device is configured to be operated by an electronic control unit as a function of at least one of the following parameters: instantaneous operating speed of the suction roll; length of the sheet; and paper weight.
8 . The suction roll of a web, or sheet, of paper, according to claim 7 wherein said electronic control unit is configured to operate said actuation device to cause said vacuum distribution device to move in a continuous or alternating way between at least two predetermined positions.
9 . The suction roll of a web, or sheet, of paper, according to claim 2 , wherein said vacuum distribution device comprises a first and a second sealing member integral to said fixed tubular body at opposite sides with respect to said, or each, aperture, said first and second sealing members being positioned longitudinally to said tubular body.
10 . The suction roll of a web, or sheet, of paper, according to claim 1 , wherein said vacuum distribution device further comprises a plurality of sealing members integral and positioned longitudinally to said tubular body, each sealing member of said plurality being associated to at least one row of suction holes arranged to pneumatically connect said external lateral surface with said device for generating a predetermined vacuum degree.
11 . The suction roll of a web, or sheet, of paper, according to claim 1 , wherein: said vacuum distribution device comprises a plurality of sealing members arranged longitudinally to said tubular body, said plurality of sealing members being positioned on at least one movable support configured to move with respect to said tubular body and to said fixed tubular body; and said displacement device is configured to cause a rotation of said movable support about said longitudinal rotation axis.
12 . The suction roll of a web, or sheet, of paper, according to claim 2 , wherein said displacement device is configured to cause a rotation of said fixed tubular body about said longitudinal rotation axis: in a sense of rotation consistent with said predetermined sense of rotation of said tubular body to postpone said releasing instant of said sheet or web of paper with respect to a reference releasing time, or in the sense opposite to said predetermined sense of rotation of said tubular body to anticipate said releasing instant of said sheet or web of paper with respect to said predetermined reference releasing time.
13 . The suction roll of a web, or sheet, of paper, according claim 1 selected from the group consisting of: an advancement roll configured to cause the web or sheet of paper to move along a predetermined advancing direction in a paper converting machine; a cut roll configured to cut a web of paper into a plurality of sheets of predetermined length; and a folding or interfolding roll, configured to fold or interfold a web or sheet of paper according to a predetermined folding or interfolding configuration.
14 . The suction roll of a web, or sheet, of paper, according to claim 1 , wherein said plurality of longitudinal rows of rows of suction holes are organized according to a plurality of suction groups, each suction group of said plurality comprising at least two longitudinal rows of holes close to each other.
15 . The suction roll of a web, or sheet, of paper, according to claim 1 wherein: said plurality of longitudinal rows of rows of suction holes are organized according to a plurality of suction groups, each suction group of said plurality comprising at least three longitudinal rows of holes close to each other; and the distance between two following suction groups of said plurality is equal to the length of the processed sheet.
16 . A folding or interfolding unit of a web, or sheet, of paper, comprising: a first and a second suction roll of a web, or sheet, of paper, according to claim 1 , said first and second suction rolls being configured to fold or interfold said web or sheet of paper according to a predetermined folding or interfolding configuration at a folding or interfolding zone arranged between said first and second suction rolls; a first and a second plurality of detaching fingers configured to cause said web or sheet of paper to be detached from the external lateral surface of the respective suction roll; and a first and a second actuation group configured, respectively, to cause a back-and-forth oscillatory motion of said first and second pluralities of detaching fingers from/towards said folding or interfolding zone, in such a way to cause the detachment of a respective web or sheet of paper, respectively, from said first and second suction roll, wherein said first and second actuation groups comprise, furthermore, a phase adjustment device configured to introduce a delay or an anticipation, in said oscillatory motion, in such a way to delay or anticipate the instant in which said first and second pluralities of detaching fingers are arranged to hit said respective web or sheet of paper to cause the detachment of the same from said respective suction roll.
17 . A method for feeding a web or sheet of paper in a paper converting machine comprising the steps of: sucking a web or sheet of paper, or similar products, on an external lateral surface of a suction roll comprising: a tubular body configured to rotate about a longitudinal rotation axis in a predetermined sense of rotation, said tubular body being provided with said external lateral surface and with an internal lateral surface pneumatically communicated to each other through a plurality of suction holes organized according to a plurality of longitudinal rows; a suction chamber defined within said suction roll and pneumatically connected to a vacuum generation device configured to generate a predetermined vacuum degree; and a vacuum distribution device configured to selectively put into pneumatic communication said suction chamber with at least one row of suction holes of said plurality, at determined angular positions of said tubular body, and to cause the processed sheet or web of paper to be sucked, and to adhere at a corresponding portion of said external lateral surface of said suction roll arranged between a catching point and a releasing point having determined angular positions; and moving said vacuum distribution device in such a way to change the angular position of said catching point and/or of said releasing point of said web or sheet of paper and, therefore, to anticipate, or postpone, the catching instant and/or the releasing instant wherein said web or sheet of paper adheres to or leaves, said external lateral surface of said suction roll, wherein moving said vacuum distribution device is performed during said rotation of said tubular body about said longitudinal rotation axis.

Description

FIELD OF THE INVENTION The present invention relates to the technical field of paper converting, and similar products, and, in particular, it relates to a machine for interfolding a web, or sheet, of paper, equipped with at least one suction roll, in particular a cut roll, or a folding or interfolding roll, provided with suction holes which are connected to a vacuum system to cause the sheet, or web, of paper to adhere on its surface. DESCRIPTION OF THE PRIOR ART As it is known, many machines are used in the paper industry, for example winding and interfolding machines, which are equipped with systems for causing the processed web, or sheet of paper, to adhere on the surface of the rolls, in determined working steps, in such a way to guide the sheets or webs of paper along a desired path through the machine. In particular, these systems are used to carry out the very important operations of cutting the paper, or transferring very quickly the paper same from a roll to another one, or also to provide the final fold of the paper in order to obtain a folded or interfolded product. The systems which cause the aforementioned adhesion can provide mechanical pliers, or pneumatic suction systems. In the case of pneumatic systems, a device for generating a determined vacuum degree, normally a vacuum pump, is provided that is pneumatically connected to the inner part of the suction roll. More precisely, the surface of the suction roll provides a determined number of rows of suction holes distributed on the surface of the roll in such a way to cause the processed web or sheet to adhere only at determined portions. Normally, a suction roll provides 3, or 4, couples of rows of suction holes close to each other positioned at 120°, or 90°, one with respect to the other, and pneumatically connected with the vacuum generation device at determined angular positions of the suction roll, in such a way to cause the processed web or sheet of paper to adhere at a determined portions of the surface of the suction roll. A known type of suction rolls is, for example, described in EP1457444. In particular, the suction roll of EP1457444, that can be an advancement roll, or a folding roll, comprises a tubular body provided with the aforementioned plurality of rows of holes, for example 4 couples of rows of holes arranged at 90° with respect to each other and configured to rotate during working conditions about a longitudinal axis. The suction roll is, furthermore, provided with a second tubular body coaxially mounted within the aforementioned tubular body. In particular, the inner tubular body is pneumatically connected to a device for generating a determined vacuum degree and two sealing members are, furthermore, provided that extend longitudinally between the aforementioned tubular bodies at opposite sides with respect to the, or each aperture. In this way, the inner tubular body, the internal surface of the outer tubular body and the two longitudinal sealing members, define a suction chamber at a determined position of the suction roll. Therefore, the web or sheet of paper is sucked by the suction chamber at a first point P1 having a first predetermined angular position, at which a longitudinal row of suction holes is positioned by the rotation of the outer tubular body at the aforementioned suction chamber, or, more precisely, immediately downstream of the sealing member. The web or sheet of paper is, then, released at a second point P2, having a second predetermined angular position, at which the aforementioned longitudinal row of suction holes is positioned by the rotation of the outer tubular body at a position external to the aforementioned suction chamber, or, more precisely, immediately downstream of the second sealing member. Therefore, the web or sheet of paper is held on the portion of the suction roll surface arranged between the first and second points P1 and P2 to carry out the aforementioned cut, or fold, or advancement operation along the machine. However, the solution described in EP1457444, as well as other analogous prior art solutions, have some drawbacks. In particular, the advancement speed of the processed web or sheet of paper along the machine in which the suction roll described in EP1457444 is installed, as well as other analogous suction rolls, cannot overcome a predetermined threshold value, normally about 150-200 m/min, value that is imposed by constructional and functional limits of determined machine components. The aforementioned values of the advancement speed of paper along the machine are also used, together with the path to be followed, to design the suction roll, in particular for positioning the sealing members at predetermined angular positions. If, instead, the aforementioned speed values used to design the suction roll are not observed during the functioning of the machine, it is possible to have problems of different kind. In particular, if the aforementioned threshold values are exceeded, due