Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H45/00—Folding thin material
  • B65H45/12—Folding articles or webs with application of pressure to define or form crease lines
  • B65H45/24—Interfolding sheets, e.g. cigarette or toilet papers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2406/00—Means using fluid
  • B65H2406/30—Suction means
  • B65H2406/36—Means for producing, distributing or controlling suction
  • B65H2406/361—Means for producing, distributing or controlling suction distributing vacuum from stationary element to movable element
  • B65H2406/3614—Means for producing, distributing or controlling suction distributing vacuum from stationary element to movable element involving a shoe in sliding contact with an inner section of the periphery of a rotating element

Definitions

• the present invention relates to the technical field of paper converting, and related products, and, in particular, relates to a machine for interfolding a web, or sheet, of paper, equipped with at least a processing roll, in particular a folding, or interfolding, roll having a particular arrangement of the suction holes, which, connected to a vacuum system, cause the sheet, or web, of paper to adhere to the surface of the roll same.
• these systems are used to carry out the fundamental operations of cutting the paper, or transferring very quickly the paper same from a roll to another one, or also folding the paper.
• the systems causing the above mentioned adhesion provide mechanical clamps, or pneumatic suction systems.
• a device for generating a determined vacuum level, that is pneumatically connected with the internal part of the rolls. More precisely, the surface of the advancing rolls provides a determined number of couples of longitudinal rows of suction holes, normally 3, or 4, couples of rows of holes. These are pneumatically connected to the vacuum generation device in such a way to cause the processed paper to adhere at a determined sector of the roll surface .
• a known kind of advancing rolls provides a bell distributor that is coupled to the folding, or interfolding, roll, at an end, and that divides the roll surface in sectors where the paper is sucked, i.e. where the rows of holes suck, and in sectors where the processed sheet is, instead, not held by the roll and, therefore, can be transferred on another roll, for example in order to carry out the folding of the sheet.
• the bell distributor is coaxially arranged with respect to the roll, but unlike the latter is fixed, because mounted on the roll shaft by means of bearings.
• the bell distributor has an opening having a curved shape, which pneumatically communicates with the above mentioned vacuum generation device, and extending for a certain angle.
• the curved opening of the distributor selectively communicates with the longitudinal channels of the roll and, therefore, with the rows of holes pneumatically communicating with the same.
• a portion of the surface of the folding, or interfolding, roll is obtained where the sheet, or the web of paper, adheres, due to the suction action produced on the same by the vacuum generation device.
• this kind of folding, or interfolding, roll has some drawbacks.
• the longitudinal channels are at atmospheric pressure. Therefore, a row of holes starts to suck the sheet of paper on the roll surface only after that all the air has been removed from the longitudinal channel through which pneumatically communicates with the suction device. Therefore, a delay occurs between the time when the longitudinal channel is put in pneumatic communication with the vacuum generation device through the curved opening of the distributor, and the time when the surface portion of roll of the corresponding row of holes really starts to suck the paper on the roll surface.
• the longitudinal channel is arranged in a position that is external to the position of the curved opening, even if is no more pneumatically connected with the vacuum generation device.
• the folding, or interfolding method provides to transversally cut, or separated by tears, the sheets obtained from at least a web. Then, a staggering of the sheets is obtained, in order to create a sequence of staggered sheets. These are, then, transferred on folding, or interfolding, rolls, having rows of suction holes in order to alternatingly hold the sheets on their surfaces and to obtain an interfolded configuration.
• the folding, or interfolding, rolls, described in EP0982256 provide a determined number of couples of rows of suction holes distributed on the surface of the interfolding rolls.
• the suction holes of each couple are oriented according to parallel directions.
• the 2 close rows of suction holes that means the one sucking the tail of a sheet, and the one sucking the head of the following sheet, does not release the respective processed sheet, or web, of paper at a same angular position, that means corresponding to a same central angle .
• roll 1 provides inside two zones separated from each other by a sealing 28 in such a way that zone 27 is sucked, for example connected to a vacuum pump, whilst zone 27 is not sucked.
• zone 27 is sucked, for example connected to a vacuum pump, whilst zone 27 is not sucked.
• the first row 30' a of suction holes 3' a of the couple of close rows 30' a and 30'b releases the processed sheet 100'b and the tail of the sheet 100' c at the releasing point P2 (see figure 2)
• the second row 30'b of suction holes 3'b releases, instead, the respective sheets 100'b and 100' a, at the realising point P* after having held on the external lateral surface 11' of roll 1'.
• the realising point P2 therefore, precedes the realising point P* in the clockwise rotation direction of roll 1 according to arrow FI. Furthermore, at the realising point P2, a medial front portion of sheet 100'b, i.e. the tail of sheet 100'c, and a first portion of sheet 100'b , are released, whilst at the point P*, a medial rear portion of sheet 100'b, and the head of sheet 100' a are released. Therefore, at the realising point P2 a first front portion of sheet 100'b is released, whilst at the following realising point P*, a second rear portion of sheet 100'b is released, thus forming of wrinkles, or folds 105' on the same.
• the "folding fingers" operates in order to transfer the sheets 100' a, 100'b and 100' c on a formation table 155' positioned downstream of the rolls for folding, or interfolding, the above mentioned folds and wrinkles 105' of the sheet are also produced in the forming stack 150' , i.e. in the stack of folded, or interfolded, sheets, thus compromising the quality of the final product.
• a roll, according to the invention for folding, or interfolding, a web, or sheet of paper, fed along an advancing direction in a paper converting machine, or similar machines, said roll for folding, or interfolding, comprising:
• tubular body configured to rotate about a longitudinal rotation axis, said tubular body being provided of an external lateral surface and of an internal lateral surface pneumatically communicating through a plurality of suction holes organized in a predetermined number of longitudinal rows two by two close to each other, in such a way to obtain a corresponding plurality of couples of close suction holes ;
• a suction chamber provided internally to said roll for folding, or interfolding, and pneumatically connected to a suction device configured to generate a predetermined vacuum level
• a vacuum distribution device configured to selectively put in pneumatic connection said suction chamber with at least a row of suction holes of said plurality, at predetermined angular positions of said tubular body in such a way to cause the processed sheet, or web, of paper, to adhere to corresponding portions of said external lateral surface of said roll for folding, or interfolding;
• the above mentioned incident planes intersect each other in an intersection line r ⁇ parallel to the rotation axis of roll.
• intersection line r ⁇ is positioned at a distance from the above disclosed suction holes smaller than the distance of the same from the rotation axes of the roll of each of said couple of close suction holes.
• the above mentioned angle Q can have an amplitude comprised between 4° and 15°.
• the close longitudinal rows of suction holes are aligned with respect to the direction longitudinal to the roll.
• the axes of a couple of suction holes i.e. of the suction holes belonging to two different rows of a couple of close longitudinal rows of suction holes, lie on a same plane orthogonal to said longitudinal axis.
• the axes of the suction holes belonging to two close rows and arranged on a same circumference coaxial to the longitudinal rotation axis of roll lie on a plane orthogonal to the longitudinal rotation axis same.
• the close longitudinal rows of suction holes are staggered to each other with respect to the direction longitudinal to the roll. Therefore, in this case, the axes of the respective suction holes lie on different planes
• a machine for folding, or interfolding, a web, or sheet, of paper comprises a unit for folding, or interfolding, equipped with a first and a second roll for folding, or interfolding, as above disclosed, configured to be counter-rotating .
• a method for making the suction holes of a roll for folding, or interfolding, in a paper converting machine comprises the steps of:
• a roll having a tubular body having an external lateral surface and an internal surface, said roll being provided of a longitudinal axis;
• drilling said roll by said drilling tool comprising the steps of:
• said first and second predetermined directions belonging to incident planes (ya,yb), said incident planes (ya,yb) forming an angle Q having amplitude comprised between 2° and 20°;
• the above mentioned drilling step is repeated in predetermined angular positions of said roll in order to make a predetermined number of couples of close longitudinal rows of suction holes on said roll.
• FIG. 1 diagrammatically shows an interfolding unit of prior art
• FIG. 2 shows an enlargement of a roll for folding, or interfolding, of the interfolding, or folding, unit of prior art shown in figure 1 in order to highlight some technical characteristics
• FIG. 3 diagrammatically shows in a perspective side elevation view a first embodiment of a folding, or interfolding, roll, according to the invention
• - Fig. 4 diagrammatically shows a partially sectioned enlargement, of a portion of the external lateral surface of the folding, or interfolding, roll of figure 3;
• - Fig. 5 shows an enlargement of a portion of transversal section of roll of figures 3 and 4 in order to highlight some characteristics;
• FIG. 6 diagrammatically shows a perspective side elevation view of an alternative embodiment of the folding, or interfolding, roll, of figure 3;
• Fig. 7 diagrammatically shows a partially sectioned enlargement of a portion of the external lateral surface of the folding, or interfolding, roll of figure 6;
• FIG. 8 shows an enlargement of a portion of transversal section of roll of figures 6 and 7 in order to highlight some characteristics
• FIG. 9 diagrammatically shows a folding, or interfolding, unit, equipped with 2 folding, or interfolding, rolls, according to the invention
• FIG. 10 diagrammatically shows a perspective side elevation view of a possible embodiment of a machine that is able to carry out the method, according to the invention, for carrying out the longitudinal rows of suction holes in a roll for obtaining the folding, or interfolding, roll, according to the invention.
• a roll 1 for folding, or interfolding, a web, or sheet, of paper, 100' fed along an advancing direction in a paper converting machine, or similar machines comprises a tubular body 10 configured to rotate about a longitudinal rotation axis 101. More precisely, the tubular body 10 of the roll 1 for folding provides an external lateral surface 11 and an internal lateral surface 12 pneumatically communicating one another through a plurality of suction holes 3a, 3b. These are organized in a predetermined number of longitudinal rows distributed on the surface of the roll 1 for folding in such a way to be two by two close to each other.
• the folding, or interfolding, roll, 1 furthermore, provides a suction chamber 20 provided internally to the above mentioned tubular body 10, and pneumatically connected to a suction device, not shown in the figure for reasons of simplicity, but, however, of known kind for a skilled person in the field, and configured to generate a predetermined vacuum level.
• a vacuum distribution device 50 is, furthermore, provided positioned between the internal lateral surface 12 of folding roll 1 and the suction chamber 20. More precisely, the vacuum distribution device 50 is configured to selectively put in pneumatic connection the suction chamber 20 with at least a row of suction holes 30a, 30b of the above mentioned plurality, at predetermined angular positions of the tubular body 10. In this way the suction of the processed sheet, or web, of paper 100 is carried out, and its adhesion only at determined portions of the external lateral surface 11 of folding roll 1.
• the close longitudinal rows 30a, 30b of suction holes 3a, 3b of the folding, or interfolding, roll, 1 are arranged according to directions lying on incident planes ya and yb .
• the sheet 100, which is held by the suction action of the holes 3a, 3b on the external lateral surface 11 of the folding roll 1 is released at a same releasing angle, i.e. at a same angular position, thus overcoming the above mentioned drawbacks of the solutions of prior art.
• the above mentioned close longitudinal rows 30a and 30b of longitudinal rows of suction holes 3a and 3b are staggered to each other along the longitudinal direction of the roll.
• the suction holes 3a, 3b of each couple of close suction holes are, therefore, positioned on respective directions intersecting each other before reaching the axis 101 of the folding, or interfolding, roll 1.
• the close longitudinal rows 30a and 30b of suction holes 3a, 3b can be aligned to each other with respect to the direction longitudinal to roll 1.
• the axes 103a and 103b of two suction holes 3a, 3b, and therefore of the suction holes belonging to two different longitudinal rows of two close suction rows 30a and 30b can lie on a same plane orthogonal to the longitudinal axis 101.
• the above mentioned incident planes ya and yb form an angle Q of predetermined amplitude, for example an amplitude comprised between 2° and 20°, preferably an amplitude comprised between 4° and 15°.
• the above mentioned close longitudinal rows 30a and 30b of rows of suction holes 3a and 3b are staggered to each other along the longitudinal direction of roll. Therefore, the suction holes 3a and 3b of two close rows 30a and 30b, are oriented with the respective axes 103a and 103b positioned along respective skew directions that means belonging to different planes.
• a “mixed” solution of the embodiments above disclosed is also provided, that means an embodiment wherein the folding, or interfolding, roll, 1 provides a plurality of suction holes comprising both couples of close longitudinal rows 30a and 30b of suction holes 3a and 3b such that the axes 103a and 103b of two suction holes are positioned on a same plane orthogonal to the longitudinal axis 101 of folding roll 1, and two close longitudinal rows 30a and 30b are longitudinally staggered to each other, i.e.
• the axes 103a and 103b of the suction holes 3a and 3b of the two longitudinal rows 30a and 30b are skew and lie on different planes orthogonal to the longitudinal axis 101 of folding roll 1.
• the vacuum distribution device 50 can provide a fixed tubular body 25 coaxially mounted within the above mentioned tubular body 10, communicating with a system for generating a predetermined vacuum level. More precisely, the fixed tubular body 25 provides an opening 26 and is associated to two walls 27a and 27b which are arranged longitudinally to the tubular body 10.
• the volume delimited between the two walls 27a and 27b, the fixed tubular body 25 and the internal lateral surface 12 of the folding roll 1 define the above mentioned suction chamber 20 constantly pneumatically communicating with the vacuum generation system. Therefore, the rotation of folding roll 1 about its longitudinal axis 101, selectively brings the different longitudinal rows 30a, 30b of suction holes 3a, 3b of the folding roll 1 to pneumatically communicate with the vacuum generation system, thus causing the web, or sheet, of paper to adhere on the roll surface, between the position of the first longitudinal wall 27a and the position of the second longitudinal wall 27b.
• the two longitudinal walls 27a and 27b, at ends directed towards the internal lateral surface 12 of the folding roll 1, are advantageously provided with pneumatic sealing elements 28a and 28b, in particular made of rubber, plastic, or similar materials, in order to assure the necessary conditions of pneumatic sealing, thus insulating the suction chamber from the remaining portion of volume defined between the internal lateral surface 12 of the folding roll 1 and the fixed tubular body 25.
• the longitudinal walls 27a, 27b can be provided with push elements, preferably springs, not shown in the figure for reasons of simplicity, and configured to push the above mentioned sealing elements 28a and 28b against the internal lateral surface 12 of the folding roll 1.
• a method for making the above mentioned suction holes of the roll for folding, or interfolding, above described with reference to figures from 3 to 9, can provide the succession of steps described in the following with reference to figure 10.
• folding roll 1 can be installed on a support structure of which, in figure 10, can be seen two support arms 210a and 210b arranged, in use, to engage the roll 1 at opposite sides.
• the method provides, in particular, to use a drilling tool 300, acting along a predetermined drilling direction and mobile from and towards roll 1 in order to approach the external lateral surface 11 of roll 1, making the suction hole, and, therefore, departing from the surface 11 same.
• the drilling tool 300 is arranged to move on a track 350 oriented longitudinally to roll 1, in such a way to move the same along a direction 320 parallel to axis 101.
• the drilling tool 300 is at first positioned with respect to roll 1 along a first predetermined drilling direction. Then, the drilling tool is moved towards roll 1 along the above disclosed first predetermined direction up to make a suction hole 3a in roll 1 having an axis 103a oriented along the above mentioned first predetermined direction.
• a step follows of withdrawing of drilling tool 300 from roll 1 still along the above mentioned first predetermined direction and the translating step of the drilling tool 300 along the track 350 in order to position the same at a second point where the following suction hole 3a of the same row 30a is made, and so on up to cover all the length of roll 1.
• angle oil can be equal to, or substantially equal to, angle Q formed by the incident planes ya and yb shown in figure 5.
• sequence of steps above described for the row 30a of suction holes 3a is therefore repeated for the row 30b of suction holes 3b in such a way to obtain a couple of close longitudinal rows 30a and 30b of holes.
• a rotation of roll 1 about its axis 101 follows, that is carried again by the above mentioned support arms 210a and 210b, but of a second predetermined angle cx2, in such a way to position the roll 1 with respect to the drilling tool 300 at the angular position where the two close rows of suction holes have to be made.
• the above mentioned sequence of operations is, therefore, repeated up to make a predetermined number of suction holes on the worked roll.
• Angle 2 can be calculated at the design step of the machine, by dividing the development of the folding roll 1 by the number of sheets, which have to lie on the development of the folding roll 1.

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• Folding Of Thin Sheet-Like Materials, Special Discharging Devices, And Others (AREA)
• Paper (AREA)

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Publications (1)

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Citations (6)

• 2018
  • 2018-07-26 IT IT102018000007513A patent/IT201800007513A1/it unknown
• 2019
  • 2019-07-23 WO PCT/IB2019/056274 patent/WO2020021446A1/en active Application Filing

Patent Citations (6)

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