SEPARATION UNIT AND A DISPENSER COMPRISING A SEPARATION UNIT

Abstract

A separation unit for separating a web material along preformed lines of weakness. The separation unit includes a first roller, and a second roller having a rotational axis extending parallel with the rotational axis of the first roller. The rotational axis of the second roller is positioned at a distance from the rotational axis of said first roller. Each of the first and second rollers is provided with at least one protrusion element. Outer portions of the protrusion elements on the first roller are partially overlapping with outer portions of the protrusion elements on the second roller with a radial overlap length, thus forming an undulating passage for a web material between the rollers. The distance between the rotational axes of the first and the second rollers is adjustable, enabling the radial overlap length in the undulating passage to be variable. Also, a dispenser including the separation unit.

Claims

1-22. (canceled)

23. A separation unit for separating a web material along preformed lines of weakness, said separation unit having a width direction and comprising at least a first roller having a rotational axis extending in said width direction, a rotation direction, and a web width extending in said width direction, and at least a second roller having a rotational axis extending parallel with said rotational axis of said first roller, a rotation direction, and a web width extending in said width direction, said rotational axis of said second roller being positioned at a distance from said rotational axis of said first roller, said distance extending in a direction perpendicular to said width direction, wherein the rotation direction of the first roller is opposite the rotation direction of the second roller, wherein each of said first and said second rollers is provided with at least one protrusion element extending perpendicularly from said axes, wherein each of said protrusion elements has a maximum width in said width direction, a maximum radial extension from said rotational axes, an inner portion adjacent to said rotational axes, and an outer portion remote from said rotational axes, wherein said outer portions of said protrusion elements on said first roller are arranged in a staggered relationship with said outer portions of said protrusion elements on said second roller, wherein said outer portions of said protrusion elements on said first roller are partially overlapping with said outer portions of said protrusion elements on said second roller with a radial overlap length, thus forming an undulating passage for a web material between said rollers, wherein said distance between said rotational axes of said first and said second rollers is adjustable, enabling said radial overlap length in said undulating passage to be variable, wherein a biasing means arranged with said first and second rollers enables an automatic adjustment of said distance between said rotational axes of said first and said second rollers, wherein the separation unit is configured such that the preformed lines of weakness will rupture in the separation unit to separate a sheet of web material, wherein said first roller is movably suspended, perpendicularly to said first rotational axis, and wherein said biasing means is arranged to bias said first roller towards said second roller, wherein the separation unit further comprises a cradle, said cradle being pivotably suspended to pivot about a pivot axis substantially parallel with said rotational axes, wherein said first roller is suspended in said cradle.

24. The separation unit according to claim 23, wherein said rollers are arranged such that said distance between said rotational axes of said first and said second rollers is manually changeable.

25. The separation unit according to claim 23, wherein said biasing means engages with said cradle to bias said first roller towards said second roller.

26. The separation unit according to claim 23, wherein said rotational axis of said second roller is fixed.

27. The separation unit according to claim 23, wherein said biasing means biases said first roller towards an end position, from which end position said first roller is movable in a direction away from said second roller.

28. The separation unit according to claim 23, wherein said cradle is biased to abut against a stopper device, and wherein said first roller is arranged in said end position when said cradle abuts against said stopper device.

29. The separation unit according to claim 28, wherein said stopper device is movable between at least two fixed positions to define at least two corresponding end positions for said first roller.

30. The separation unit according to claim 23, wherein the radial overlap length is between 4-40 mm, prior to variance allowed by the biasing means.

31. The separation unit according to claim 23, wherein said biasing means comprises a spring.

32. The separation unit according to claim 23, comprising a first guiding part separate from said first roller, wherein said first guiding part is arranged in connection with said first roller and comprises a first guiding surface for said web material.

33. The separation unit according to claim 32, wherein said first guiding part is connected with, and movable together with, said cradle.

34. The separation unit according to claim 32, comprising a second guiding part separate from said second roller, wherein said second guiding part is arranged in connection with said second roller and comprises a second guiding surface for said web material.

35. The separation unit according to claim 23, wherein said protrusion elements are disc elements.

36. A dispenser for a web material comprising preformed lines of weakness, the dispenser comprising a housing defining a web material reservoir, and a dispensing opening, wherein said dispenser comprises a separation unit according to claim 23.

37. The dispenser according to claim 36, comprising a control unit for determining a correct tension and path of said web material.

38. The dispenser according to claim 36, wherein said dispenser is adapted for containing a web material comprising preformed lines of weakness, said web material being Z-folded to form a stack.

39. The dispenser according to claim 36, wherein said dispenser is adapted for containing a web material comprising preformed lines of weakness, said web material being in the form of a roll.

40. The dispenser according to claim 36, wherein said dispenser further comprises a feeding mechanism for feeding said web material.

41. The dispenser according to claim 38, wherein said reservoir is adapted to contain said web material, and wherein a leading portion of said web material is arranged to be supported at least partially along a dispensing path from said reservoir to said dispensing opening.

42. The dispenser according to claim 41, wherein said leading portion is arranged to extend upwardly from a top of said stack.

43. The separation unit according to claim 23, wherein a nip is formed between said first and second rollers, through which nip the web material is arranged to pass, wherein the separation unit is configured to break the preformed line of weakness within the nip in order to separate the web material.

44. The dispenser according to claim 36, wherein a nip is formed between said first and second rollers, through which nip the web material is arranged to pass, wherein the separation unit is configured to break the preformed line of weakness within the nip in order to separate the web material.

45. A separation unit for separating a web material along preformed lines of weakness, said separation unit having a width direction and comprising at least a first roller having a rotational axis extending in said width direction and a web width extending in said width direction, and at least a second roller having a rotational axis extending parallel with said rotational axis of said first roller and a web width extending in said width direction, said rotational axis of said second roller being positioned at a distance from said rotational axis of said first roller, said distance extending in a direction perpendicular to said width direction, wherein each of said first and said second rollers is provided with at least one protrusion element extending perpendicularly from said axes, wherein each of said protrusion elements has a maximum width in said width direction, a maximum radial extension from said rotational axes, an inner portion adjacent to said rotational axes, and an outer portion remote from said rotational axes, wherein said outer portions of said protrusion elements on said first roller are arranged in a staggered relationship with said outer portions of said protrusion elements on said second roller, wherein said outer portions of said protrusion elements on said first roller are partially overlapping with said outer portions of said protrusion elements on said second roller with a radial overlap length, thus forming an undulating passage for a web material between said rollers, wherein said distance between said rotational axes of said first and said second rollers is adjustable, enabling said radial overlap length in said undulating passage to be variable, wherein a biasing means arranged with said first and second rollers enables an automatic adjustment of said distance between said rotational axes of said first and said second rollers, wherein the separation unit is configured such that the preformed lines of weakness will rupture in the separation unit to separate a sheet of web material, wherein said first roller is movably suspended, perpendicularly to said first rotational axis, and wherein said biasing means is arranged to bias said first roller towards said second roller, wherein the separation unit further comprises a cradle, said cradle being pivotably suspended to pivot about a pivot axis substantially parallel with said rotational axes, wherein said first roller is suspended in said cradle, wherein the separation unit is configured for manual separation of web material by a user pulling on a leading portion of the web material.

46. The separation unit according to claim 45, wherein said rollers are arranged such that said distance between said rotational axes of said first and said second rollers is manually changeable.

47. The separation unit according to claim 45, wherein said biasing means engages with said cradle to bias said first roller towards said second roller.

48. The separation unit according to claim 45, wherein said rotational axis of said second roller is fixed.

49. The separation unit according to claim 45, wherein said biasing means biases said first roller towards an end position, from which end position said first roller is movable in a direction away from said second roller.

50. The separation unit according to claim 45, wherein said cradle is biased to abut against a stopper device, and wherein said first roller is arranged in said end position when said cradle abuts against said stopper device.

51. The separation unit according to claim 50, wherein said stopper device is movable between at least two fixed positions to define at least two corresponding end positions for said first roller.

52. The separation unit according to claim 45, wherein the radial overlap length is between 4-40 mm, prior to variance allowed by the biasing means.

53. The separation unit according to claim 45, wherein said biasing means comprises a spring.

54. The separation unit according to claim 45, comprising a first guiding part separate from said first roller, wherein said first guiding part is arranged in connection with said first roller and comprises a first guiding surface for said web material.

55. The separation unit according to claim 54, wherein said first guiding part is connected with, and movable together with, said cradle.

56. The separation unit according to claim 54, comprising a second guiding part separate from said second roller, wherein said second guiding part is arranged in connection with said second roller and comprises a second guiding surface for said web material.

57. The separation unit according to claim 45, wherein said protrusion elements are disc elements.

58. A dispenser for a web material comprising preformed lines of weakness, the dispenser comprising a housing defining a web material reservoir, and a dispensing opening, wherein said dispenser comprises a separation unit according to claim 45.

59. The dispenser according to claim 58, comprising a control unit for determining a correct tension and path of said web material.

60. The dispenser according to claim 58, wherein said dispenser is adapted for containing a web material comprising preformed lines of weakness, said web material being Z-folded to form a stack.

61. The dispenser according to claim 58, wherein said dispenser is adapted for containing a web material comprising preformed lines of weakness, said web material being in the form of a roll.

62. The dispenser according to claim 58, wherein said dispenser further comprises a feeding mechanism for feeding said web material.

63. The dispenser according to claim 60, wherein said reservoir is adapted to contain said web material, and wherein a leading portion of said web material is arranged to be supported at least partially along a dispensing path from said reservoir to said dispensing opening.

64. The dispenser according to claim 63, wherein said leading portion is arranged to extend upwardly from a top of said stack.

65. The separation unit according to claim 45, wherein a nip is formed between said first and second rollers, through which nip the web material is arranged to pass, wherein the separation unit is configured to break the preformed line of weakness within the nip in order to separate the web material.

66. The dispenser according to claim 63, wherein a nip is formed between said first and second rollers, through which nip the web material is arranged to pass, wherein the separation unit is configured to break the preformed line of weakness within the nip in order to separate the web material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, of which:

[0067] FIGS. 1a, 1b and 1c show a separation unit according to the present invention;

[0068] FIG. 2 shows the separation unit according to the present invention seen in the width direction;

[0069] FIG. 3 shows protrusion elements having different dimensions and differently shaped outer portions;

[0070] FIG. 4 shows a dispenser comprising the separation unit according to the present invention;

[0071] FIG. 5 illustrates embodiments of a dispenser for a web material comprising preformed lines of weakness.

[0072] FIG. 6 illustrates embodiments of a separation unit for separating a web material along preformed lines of weakness;

[0073] FIG. 7 illustrates the separation unit of FIG. 6 with covers and selected portions removed; and

[0074] FIGS. 8 and 9 illustrate cross sections through the separation unit illustrated in FIGS. 6 and 7.

DETAILED DESCRIPTION

[0075] The present invention will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Disclosed features of example embodiments may be combined as readily understood by one of ordinary skill in the art to which this invention belongs. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

[0076] FIGS. 1a and 1b show a separation unit 1 according to the present invention. The separation unit 1 comprises a first roller 2 and a second roller 3, each extending in a width direction and comprising plurality of protrusion elements 4 being spaced along the rollers 2, 3 and protruding perpendicular from the rollers 2, 3. The rollers 2, 3 are positioned at a distance d.sub.1 from each other, wherein the distance d.sub.1 is extending in a direction perpendicular to the width direction of the rollers 2, 3. In the embodiment shown in FIG. 1a, the first roller 2 comprises six protrusion elements 4, and the second roller 3 comprises four protrusion elements 4. The rollers 2, 3 have a web width W (FIG. 1c). Each of the protrusion elements 4 has a maximum width w in the width direction and a maximum radial extension r from the rollers 2, 3. In the embodiment shown in FIG. 1a, the maximum widths w and the maximum radial extensions r of all the protrusion elements 4 are the same. Each protrusion element has an inner portion 6 adjacent to rotational axes 20, 22 of the rollers 2, 3, and an outer portion 5 remote from the rotational axes 20, 22 of the rollers 2, 3, wherein the outer portions 5 of the protrusion elements 4 on the first roller 2 are arranged in a staggered relationship with the outer portions 5 of the protrusion elements 4 on the second roller 3, which is best seen in FIG. 2. The outer portions 5 of the protrusion elements 4 have a slightly curved shape. The outer portions 5 of the protrusion elements 4 on the first roller 2 are partially overlapping with the outer portions 5 of the protrusion elements 4 on the second roller 3 with a radial overlap length L. Such a configuration of the protrusion elements 4 forms an undulating passage for a web material 16 between the rollers 2, 3 (FIG. 1c).

[0077] In the embodiment shown in FIGS. 1a and 1b, no protrusion elements are placed in the central portion C of the rollers 2, 3. Such an arrangement of the protrusion elements allows the user to easily access the leading end of the web material 16 in the central portion C of the separation unit 1 (FIG. 1c).

[0078] As may be seen in FIGS. 1a and 1b, the spacing d.sub.2 between each two protrusion elements 4 is equal to or greater than the maximum width w of each protrusion element 4. Such a configuration enables the protrusion elements 4 to be relatively scarcely distributed, which provides an optimal pinch force.

[0079] Another advantageous feature of the separation unit according to the present invention is that the maximum radial extensions r of the protrusion elements are equal to or greater than the maximum widths w of the protrusion elements. As may be seen in FIGS. 1a and 1b, the protrusion elements are formed as relatively large and thin discs, which optimizes the pinch force.

[0080] FIGS. 1a, 1b, and 1c illustrate embodiments of a separation unit 1 for separating a web material 16 along preformed lines of weakness. The separation unit 1 has a width direction W and comprises a first roller 2 having a first rotational axis 20 extending in the width direction W and a web width W extending in said width direction W, and at least a second roller 3 having a second rotational axis 22 extending parallel with the first rotational axis 20 of the first roller 2 and a web width W extending in the width direction W. The second rotational axis 22 of the second roller 3 is positioned at a distance d1 from the first rotational axis 20 of the first roller 2, the distance d1 extending in a direction perpendicular to the width direction W. Each of the first and the second rollers 2, 3 is provided with at least one protrusion element 4 extending perpendicularly from the rotational axes 20, 22. Each of the protrusion elements 4 has a maximum width w in the width direction W, a maximum radial extension from each of the rotational axes 20, 22, an inner portion 6 adjacent to the respective of each rotational axis 20, 22, and an outer portion 5 remote from the respective of each rotational axis 20, 22. The outer portions 5 of the protrusion elements 4 on the first roller 2 are arranged in a staggered relationship with the outer portions 5 of the protrusion elements 4 on the second roller 3. The outer portions 5 of the protrusion elements 4 on the first roller 2 are partially overlapping with the outer portions 5 of the protrusion elements 4 on the second roller 3 with a radial overlap length L, thus forming an undulating passage for a web material 16 between the rollers 2, 3. The distance d1 between the rotational axes 20, 22 of the first and the second rollers 2, 3 is adjustable, enabling the radial overlap length L in the undulating passage to be variable.

[0081] The distance d1 between the rotational axes 20, 22 may be adjustable in different manners; either automatically by a biasing means, or manually by setting a position of the first roller 2 or the second 3, or by both automatically and manually, such as e.g. describe below. A nip is formed between the first and second rollers 2, 3, through which nip the web material is arranged to pass. A preformed line of weakness of the web material 16 may break either within the nip or outside nip, as the web material 16 passes through the nip. Thus, a sheet of web material may be separated from a leading portion of continuous web material.

[0082] FIG. 2 illustrates the separation unit 1 seen in the width direction. It is clearly shown that the outer portions 5 of the protrusion elements 4 on the first roller 2 overlap with the outer portions 5 of the protrusion elements 4 on the second roller 3.

[0083] As previously mentioned, the protrusion elements 4 may have different maximum widths w and maximum radial extension r. In FIG. 3, protrusion elements, in the form of disc elements, having different maximum widths w and different maximum radial extensions r are shown.

[0084] As mentioned above, the shape of the outer portions 5 of the protrusion elements 4 may vary. In FIG. 3, four possible shapes of the outer portions 5 are depicted. Thus, the outer portions may have a smooth surface, or may be provided with a ribbed surface.

[0085] FIG. 4 schematically shows a dispenser 7 with a separation unit 1 according to the present invention. The dispenser 7 has an outer front wall 8, two outer side walls 9 and a housing 10. The housing 10 is intended for holding a pile, or stack, of a continuous length of accordion-like folded web of towels of tissue paper or nonwoven, also referred to a web material, comprising bundles 12 of a continuous length of accordion-like folded web of towels of tissue paper or nonwoven. Thus, the housing 10 defines a web material reservoir. The bundles 12 comprise connecting means 13 between the bundles 12. The dispenser 7 comprises a guiding element 14 in the form of a curved plate 24 which extends over a segment of a web-supporting element 15. The at least one web 16 is arranged to be fed through the guiding element 14 when the dispenser 7 is in use, and at least one part of the guiding element 14 is arranged to bear against the web 16. The guiding element 14 thereby holds the at least one web 16 in place on the web-supporting element 15 so that it does not move backwards or sidewards during the use of the dispenser, or in case of web-breakage.

[0086] The unit subsequent to the guiding element 14 is separation unit 1 described above. The separation unit 1 provides an optimal pinch force acting on the web material 16, and allows the web material 16 to be separated at the desired position. The separation unit 1 depicted in FIG. 4 is configured such that both of the rollers 2, 3 are positioned inside the housing 10. It is also conceivable that one of the rotational axes is located in the outer front wall 8, such that when the outer front wall 8 is opened, the pinch force caused by the separation unit 1 is released.

[0087] The dispenser 7 illustrated in FIG. 4 comprises a stack of interfolded webs 16, whereby the dispenser 7 is configured so that the stack of interfolded webs in the housing 10 has to be lifted to position a new bundle 12 of web material in the housing 10 underneath the stack to refill the dispenser 7. Bundles 12 of interfolded webs in the dispenser 7 may be interconnected via connecting means 13, such as adhesive, adhesive tape or mechanical fasteners, such as hook and loop fasteners, at the bottom and/or top of each of the refill stacks. The web 16 is arranged to be fed upwards within the housing 10, around the web-supporting element 15 located at the top of the dispenser 7 and downwards towards the separation unit 1 and the dispensing opening 17.

[0088] FIG. 5 illustrates embodiments of a dispenser 7 for a web material comprising preformed lines of weakness. The dispenser 7 comprises a housing 10 defining a web material reservoir 70, a dispensing opening 17, and a separation unit 1 according to aspects and embodiments discussed herein. The dispenser is arranged for manual dispensing of web material through the dispensing opening 17 by a user pulling on a leading portion of the web material. In the web material reservoir 70 a stack of folded web material for dispensing sheets of web material therefrom may be provided. The web material may be Z-folded to form the stack. One or more bundles of folded web material may be used to replenish the stack of folded web when the housing 10 of the dispenser 7 is open, as illustrated in FIG. 5. A leading portion of the web material is arranged to extend from a top of the stack of web material in the web material reservoir 70 to the dispensing opening 17 of the dispenser 7. The leading portion of the web material changes direction inside the dispenser between the upper end portion of the web material reservoir 70 and the dispensing opening 17. This may for instance be achieved by a guiding element 14 as described in connection with FIG. 4. The guiding element 14 is an example of control unit for determining a correct tension and path of the web material.

[0089] In FIG. 5 the dispenser 7 is depicted in the state when no web material 16 is loaded. The separation unit 1 is positioned within the housing 10 at the same level as the dispensing opening 17, such that the perforated web 16 is separated along the preformed lines of weakness at the moment of dispensing with almost no effort from the user's side.

[0090] It should be noted that the dispenser 7 according to the present invention may be any type of automatic or non-automatic dispenser for dispensing at least one web, i.e. a plurality of webs may be dispensed simultaneously, or a plurality of different webs may be dispensed by the dispenser 7 one at a time.

[0091] The dispenser 7 is a free-standing unit, but the dispenser may also be mounted on any suitable object in any suitable manner. Furthermore, a dispenser housing 10 of a dispenser according to the present invention need not necessarily contain an entire web 16 that is to be dispensed by the dispenser 7. At least one web 16 may for example be stored outside the housing 10 and merely be fed through the housing 10 when the dispenser 7 is in use.

[0092] FIG. 6 illustrates embodiments of a separation unit 1 for separating a web material along preformed lines of weakness. The separation unit 1 comprises a first roller 2 having a first rotational axis and a second roller 3 having a second rotational axis extending parallel with the first rotational axis. The second rotational axis of the second roller 3 is positioned at a distance from the first rotational axis of the first roller 2. Each of the first and the second rollers 2, 3 is provided with at least one protrusion element 4 extending perpendicularly from the rotational axes. Each of the protrusion elements 4 has an outer portion 5 remote from the respective of each rotational axis. The outer portions 5 of the protrusion elements 4 on the first roller 2 are arranged in a staggered relationship with the outer portions 5 of the protrusion elements 4 on the second roller 3. The outer portions 5 of the protrusion elements 4 on the first roller 2 are partially overlapping with the outer portions 5 of the protrusion elements 4 on the second roller 3 with a radial overlap length, thus forming an undulating passage for a web material between the rollers 2, 3. The distance between the rotational axes 20, 22 of the first and the second rollers 2, 3 is adjustable, enabling the radial overlap length in the undulating passage to be variable. The separation unit 1 may form part of a dispenser 7, e.g. as disclosed in FIGS. 4 and 5, for dispensing sheets of web material from a stack of folded web material, or a dispenser 7 for dispensing sheets of web material from a roll of web material. The first and second rollers 2, 3 are rotatably arranged in a frame 26. The frame 26 comprises a first frame portion 28 comprising the first roller 2 and a second frame portion 30 comprising the second roller 3. The second frame portion 30 may be moved away from the first frame portion 28 to open the frame 26. The second roller 3 is moved away from the first roller 2 together with the second frame portion 30 to permit web material to be threaded between the first and second rollers 2, 3. That is, when the second roller 3 is moved away from the first roller 2, the outer portions 5 of the protrusion elements 4 do not overlap to permit the threading of the web material between the first and second rollers 2, 3. Furthermore, to facilitate threading of web material between the first and second rollers 2, 3 when the frame 26 is closed, the second roller 3 is provided with an actuation wheel 32, which may be manually rotated to advance web material between the first and second rollers 2, 3 to a graspable position.

[0093] The second rotational axis 22 is fixed in the second frame portion 30, i.e. when the frame 26 is closed the second rotational axis 22 is fixed in relation to the frame 26, as opposed to the first rotational axis 20. Namely, in the first frame portion 28, the first roller 2 is movably suspended, perpendicularly to the first rotational axis 20. Biasing means are arranged to bias the first roller 2 towards the second roller 3.

[0094] FIG. 7 illustrates the separation unit 1 of FIG. 6 with covers and selected portions removed to reveal inter alia, the first and second rollers 2, 3, the biasing means, and a suspension of the first roller 2. The first roller 2 is arranged to rotate about the first rotational axis 20 and the second roller 3 is arranged to rotate about the second rotational axis 22. During use of the separation unit 1 for separating sheets of web material from a web material comprising preformed lines of weakness, i.e. when the frame 26 is closed, the second rotational axis 22 is fixed in the separation unit 1.

[0095] As mentioned above, the first roller 2 is movably suspended, perpendicularly to the first rotational axis 20. The biasing means is arranged to bias the first roller 2 towards the second roller 3. In these embodiments the biasing means comprises two helical pressure springs 34, 34.

[0096] The separation unit 1 comprise a cradle 36. The cradle 36 is pivotably suspended to pivot about a pivot axis 38 substantially parallel with the rotational axes 20, 22. The first roller 2 is suspended in the cradle 36. Thus, the first roller 2 is movably suspended. As the cradle 36 pivots about the pivot axis 38 the first roller 2 moves with the cradle 36. Accordingly, the distance between the rotational axes 20, 22 of the first and the second rollers 2, 3 is adjustable.

[0097] The springs 34, 34 of the biasing means are illustrated in a compressed state in FIG. 7 and each abut at one end against the cradle 36 and at an opposite end to fixed portions (not shown) of the frame of the separation unit 1. Accordingly, the biasing means engage with the cradle 36 to bias the first roller 2 towards the second roller 3. The biasing means enables an automatic adjustment of the distance between the rotational axes 20, 22.

[0098] The separation unit 1 comprises a first guiding part 40 separate from the first roller 2. The first guiding part 40 is arranged in connection with the first roller 2 and comprises a first guiding surface 42 for the web material. The first guiding surface 42 may extend both upstream and downstream of the first roller 2 as well as between at least some of the protrusion elements 4 of the first roller 2. In these embodiments the first guiding part 40 extends with at least one protruding portion 44 upstream of the first roller 2, i.e. below the first roller 2 in FIG. 7. The first guiding part 40 is connected with, and movable/pivotable together with, the cradle 36. The separation unit 1 comprises a second guiding part 46 separate from the second roller 3. The second guiding part 46 is arranged in connection with the second roller 3 and comprises a second guiding surface 48 for the web material. The second guiding surface 48 may extend both upstream and downstream of the second roller 3 as well as between at least some of the protrusion elements 4 of the second roller 3.

[0099] FIG. 8 illustrates a cross section perpendicular to the first and second rotational axes through the separation unit 1 of FIGS. 6 and 7. The first and second guiding parts 40, 46 and their respective first and second guiding surfaces 42, 48, as well as the at least one protruding portion 44 are clearly visible. Moreover, the radial overlap length L of the outer portions 5 of protrusion elements 4, a fixed portion 50 of the separation unit 1 against which one of the helical springs 34 of the biasing means abuts, the cradle 36, and the pivot axis 38 are also clearly visible.

[0100] FIG. 9 illustrates a cross section perpendicular to the first and second rotational axes through the separation unit 1 of FIGS. 6, 7, and 8. The cross section is taken at one end of the first and second rollers 2, 3. The rollers 2, 3 are arranged such that the distance between the rotational axes 20, 22 of the first and the second rollers 2, 3 is manually changeable. Thus, the radial overlap length L may be set for web material of different kinds. Accordingly, the distance between the rotational axes 20, 22 of the first and the second rollers 2, 3 is adjustable.

[0101] More specifically, an end position of the first roller 2 is arranged to be manually changed. Namely, the biasing means biases the first roller 2 towards an end position, from which end position the first roller 2 is movable only in a direction away from the second roller 3. As previously mentioned, the cradle 36 is pivotable about the pivot axis 38 and the first roller 2 moves with the cradle 36. The frame of the separation unit 1 is provided with a slot 52 through which an end portion of the first roller 2 passes thus, permitting the cradle 36 and the first roller 2 to pivot about the pivot axis 38.

[0102] The separation unit 1 comprises a stopper device 54, against which the cradle 36 is biased to abut. The first roller 2 is arranged in the end position when the cradle 36 abuts against the stopper device 54. For this purpose the cradle 36 is provided with a shoulder 56, which is arranged to abut against the stopper device 54. Thus, the first roller 2 is biased towards the end position and the smallest distance between the first and second rollers 2, 3 is defined by the cradle 36 when its shoulder 56 abuts against the stopper device 54.

[0103] The stopper device 54 is movable between at least two fixed positions to define at least two corresponding end positions for the first roller 2. For this purpose the stopper device 54 in these embodiments is rotatably arranged in the separation unit 1. The stopper device 54 is manually rotatable about a portion of the separation unit 1 comprising the slot 52. The stopper device 54 is fixed by an engaging portion 58 of the stopper device 54 engaging with the frame of the separation unit 1. In order to fix the stopper device 54 the engaging portion 58 is provided with a hole 60 and the frame of the separation unit 1 is provided with at least one projection 62 arranged to extend at least partially through the hole 60. In these embodiments the stopper device 54 is movable between three fixed positions. Accordingly, the frame of the separation unit 1 is provided with three projections 62 to permit the engaging portion 58 to be fixed in one of three positions. Thus, the smallest distance between the first and second rollers 2, 3, may be set by moving the stopper device 54 to one of at least two fixed positions, i.e. three fixed positions in these embodiments. The engaging portion 58 is manually movable between the three projections 62.

[0104] Mentioned purely as an example, the radial overlap length L between the outer portions 5 of the protrusion elements 4 in each of the three fixed positions of the stopper device 54, and accordingly in the three corresponding end positions of the first roller 2, may be approx. 6 mm, approx. 7 mm, and approx. 8 mm, respectively. When the radial overlap length L is 8 mm, the biasing means may provide a force of 3.7 N towards the second roller 3. When the radial overlap length L is 6 mm, the biasing means may provide a force of 5.3 N towards the second roller 3.

[0105] The second roller 3 is provided with a cog wheel 64. Also the first roller 2 is provided with a cog wheel (not shown). The two cog wheels engage with each other. Thus when the actuation wheel 32 is rotated, both rollers 2, 3 are rotated.

[0106] Although the present invention has been described with reference to various embodiments, those skilled in the art will recognize that changes may be made without departing from the scope of the invention. It is intended that the detailed description be regarded as illustrative and that the appended claims including all the equivalents are intended to define the scope of the invention.

[0107] Example embodiments described above may be combined as understood by a person skilled in the art. Although the invention has been described with reference to example embodiments, many different alterations, modifications and the like will become apparent for those skilled in the art. For instance, the second roller 3 may be biased towards the first roller 2, instead of the first roller 2 being biased towards the second roller 3, or in addition to the first roller 2 being biased towards the second roller 3. The first and/or the second rollers 2, 3 may comprise separate roller portions aligning along the respective first and second rotational axes 20, 22.

[0108] As used herein, the term comprising or comprises is open-ended, and includes one or more stated features, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.