Method for unwinding a sheet of homogenized tobacco material wound on a bobbin with specific force and angle ranges

Abstract

The invention relates to a method to unwind a sheet of material wound in a bobbin, the method comprising: providing a bobbin of a coiled sheet, the bobbin defining an outer surface and comprising a free portion of the sheet unwound from the bobbin; arranging a compressing element on the outer surface of the bobbin, so as to define a contact line, the contact line being the line separating the free portion of the sheet from the rest of the bobbin; pressing by means of the compressing element the outer surface of the coiled sheet at the contact line with a force comprised between about (4) Newton and about (16) Newton; and unwinding the sheet from the bobbin pulling the sheet in the unwinding direction.

Claims

1. A method to unwind a sheet of homogenized tobacco material wound in a bobbin, the method comprising: providing a bobbin of a coiled sheet of homogenized tobacco material, the bobbin defining an outer surface and comprising a free portion of the sheet unwound from the bobbin; arranging a compressing element on the outer surface of the bobbin, so as to define a contact line, the contact line being a line separating the free portion of the sheet from the rest of the bobbin; pressing, with the compressing element, the outer surface of the coiled sheet at the contact line with a force comprised between about 8 Newton and about 12 Newton; and unwinding the sheet from the bobbin by pulling the free portion of the sheet in an unwinding direction such that an angle between the free portion of the sheet and a radius of the bobbin at the contact line is comprised between about 110 degrees and about 150 degrees.

2. The method according to claim 1, including: pulling the free portion of the sheet in an unwinding direction such that an angle between the free portion of the sheet and a radius of the bobbin at the contact line is about 130 degrees.

3. The method according to claim 1, including: moving the position of the compressing element while unwinding the sheet, so that an angle between the free portion of the sheet and the radius of the bobbin at the contact line is comprised between about 110 degrees and about 150 degrees during unwinding.

4. The method according to claim 1, including: attaching the compressing element to an end of an arm; fixing an opposite end of the arm to a pivot point; rotating the arm around the pivot point while unwinding while keeping the compressing element at the contact line.

5. The method according to claim 1, wherein the outer surface of the bobbin includes varying the position of a mass connected to the compressing element.

6. The method according to claim 1, comprising: selecting a value of the force pressing the outer surface of the bobbin on the basis of one or more characteristic of the bobbin or of the sheet.

7. The method according to claim 1, wherein the force applied is about 10 Newton.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 is a schematic side view of a first embodiment of the apparatus for unwinding a bobbin according to the invention;

(3) FIG. 2 is a schematic side view of a second embodiment of the apparatus for unwinding a bobbin according to the invention;

(4) FIG. 3 is a schematic side view of a third embodiment of the apparatus for unwinding a bobbin according to the invention;

(5) FIG. 4 is a schematic side view of a fourth embodiment of the apparatus for unwinding a bobbin according to the invention;

(6) FIG. 5 is a schematic side view of the first embodiment of the apparatus of FIG. 1 in a more detailed manner; and

(7) FIG. 6 is a schematic lateral view of a detail of the apparatus of FIG. 5.

(8) FIG. 7 is a schematic side view of a fifth embodiment of the apparatus for unwinding a bobbin according to the invention

(9) In FIG. 1 a schematic side view of apparatus 100 for unwinding a bobbin 1 according to the invention is shown. The apparatus 100 and the bobbin 1 form a kit 50.

(10) Bobbin 1 is formed by winding a sheet 20 of material, which defines a free portion 12 of the sheet unwound from the bobbin 1 and an outer surface 11. Preferably, the sheet 20 of material is a homogenized tobacco sheet.

(11) The separation line between the free portion 12 of the sheet 200 and the remaining of the bobbin is called contact line 13. Further, bobbin 1 defines a center 15 and a radius 14 (represented as a dotted line in the figures). Apparatus 100 includes a bobbin holder 101, a compressing element 102, and a pulling device 103.

(12) Bobbin holder 101 holds bobbin 1. Preferably, a center of the bobbin holder coincides with center 15 of bobbin 1. Preferably, bobbin 1 is inserted in bobbin holder 101. Bobbin holder is rotatable around an axis passing through its center.

(13) Compressing element 102 is adapted to be in contact with the outer surface 11 of the bobbin 1 and to press the same with a given force 109.

(14) The force is preferably directed along the radius 14 of the bobbin, in particular along the radius of the bobbin 14′ connecting the center of the bobbin with contact line 13. The force 109 is comprised between about 4 Newton and about 16 Newton and it can be selected and varied depending on the bobbin's and/or sheet's characteristics.

(15) Compressing element may change position during unwinding, that is, the position of the contact line 13 may change during unwinding.

(16) Pulling device 103 comprises a pair of rollers and pulls free portion 12 of bobbin 1 along an unwinding direction 104. The distance between the pulling device 103 and the bobbin 1 depends on the type of bobbin 1, the sheet material, the speed of unwinding and the quantity of sheet material remaining on the bobbin 1. The distance should be as small as possible, preferably less than about 2 meters, preferably less than about 50 centimeters.

(17) The free portion 12 is pulled along the unwinding direction 104 which forms a given angle with radius 14′ at the contact line. This angle is called 105 in the following.

(18) In the embodiment depicted in FIG. 1, compressing element 102 comprises a roller 106, which is positioned on outer surface 11 of bobbin 1 and defines the contact line 13, which separate free portion 12 from the rest of the bobbin 1, when the free portion is pulled as detailed below. Compressing element 102 is put into contact with the outer surface 11 of the bobbin 1 and force 109 is applied. During unwinding, the roller 106 rotates as well together with bobbin 1. Preferably, the force 109 is kept within the desired range or substantially at a fixed value.

(19) In FIG. 2 a schematic side view of a different embodiment of an apparatus 200 for unwinding a bobbin 1 according to the invention is shown.

(20) The difference between apparatus 100 according to the first embodiment above described and the apparatus 200 is in the compressing element. Therefore, the other characteristics of apparatus 200, being the same as or equivalent to those of apparatus 100, are named with the same reference numerals.

(21) Apparatus 200 includes a bobbin holder 101, a compressing element 102 and a pulling device 103.

(22) Compressing element 102 comprises a plurality of rollers 116, which are positioned in contact to outer surface 11 of bobbin 1 and define a contact line 13, which separates free portion 12 from the rest of the bobbin 1.

(23) Preferably, each of the rollers 116 has a diameter smaller than the diameter of roller 106, which was a single roller in the embodiment of FIG. 1. Rollers 116 may be identical to each other or different. Their diameters may vary. Rollers 116 apply a combined force 109 towards the center of the bobbin and along the radius of the bobbin 1.

(24) The functioning of the plurality of rollers 116 and of the apparatus 200 is as described for apparatus 100. The difference is this case that during the pulling of the free portion 12, all rollers 116 rotate (and not only a single roller as in the first embodiment). In apparatus 200 of FIG. 2 angle 105 is approximately of about 130 degrees.

(25) In FIG. 3 a schematic side view of a third embodiment of apparatus 300 for unwinding a bobbin 1 according to the invention is shown.

(26) The difference between apparatus 100 and 200 according to the first and second embodiments above described and the apparatus 300 is in the compressing element. Therefore, the other characteristics of apparatus 300, being the same as or equivalent to those of apparatuses 100 and 200, are named with the same reference numerals.

(27) Apparatus 300 includes a bobbin holder 101, a compressing element 102 and a pulling device 103.

(28) Compressing element 102 comprises a static slider 121, which is positioned in contact to outer surface 11 of bobbin 1 and defines a contact line 13, which separate free portion 12 from the rest of the bobbin 1.

(29) The functioning of the static slider 121 and of the apparatus 300 is as described for apparatus 100 or 200. In apparatus 300 of FIG. 4 angle 105 is approximately about 130 degrees.

(30) When the free portion 12 is pulled along direction 104, the bobbin 1 rotates. However, slider 121 does not rotate; it slides on top of the surface of the sheet which unwinds. Force 109 is applied by the slider 121 towards the center 15 of the bobbin along its radius.

(31) In FIG. 4 a schematic side view of a fourth embodiment of apparatus 400 for unwinding a bobbin 1 according to the invention is shown.

(32) The difference between apparatus 100, 200 and 300 according to the first, second and third embodiments above described and the apparatus 400 is in the compressing element. Therefore, the other characteristics of apparatus 400, being the same as or equivalent to those of apparatuses 100-300, are named with the same reference numerals. Apparatus 400 includes a bobbin holder 101, a compressing element 102, and a pulling device 103.

(33) Compressing element 102 comprises a combination of a static slider 121 and of a plurality or rollers 126, which are all positioned in contact to outer surface 11 of bobbin 1. Compressing element 102 defines a contact line 13, which separate free portion 12 from the rest of the bobbin 1. The functioning of combination of a static slider 121 and of a plurality or rollers 126 and of the apparatus 400 is as described for apparatus 100. In apparatus 400 of FIG. 4 angle 105 is approximately of about 130 degrees.

(34) When the free portion 12 is pulled along direction 104, the bobbin 1 rotates. Slider 121 does not rotate; it slides on top of the surface of the sheet which unwinds. Rollers 126 rotate around their axis.

(35) In FIG. 7 a schematic side view of a different embodiment of an apparatus 500 for unwinding a bobbin 1 according to the invention is shown.

(36) The difference between apparatus 100, 200, 300 and 400 above described and the apparatus 500 is in the angle 105 which is in the this embodiment of about 270 degrees.

(37) Therefore, the other characteristics of apparatus 500, being the same as or equivalent to those of apparatus 100, are named with the same reference numerals.

(38) Compressing element 102 comprises a roller 106, which is positioned on outer surface 11 of bobbin 1 and defines the contact line 13, which separate free portion 12 from the rest of the bobbin 1

(39) The free portion of the sheet makes approximately a “U-turn” around the compressing element and “returns” toward the bobbin.

(40) In FIG. 5 a more detailed view of the apparatus 100 according to the first embodiment is shown. In particular, in this figure an example of a device apt to be connected to the compressing element 102 so that the compressing element may exert a force 109 towards the center of the bobbin 1 is given. Although FIG. 5 shows the device applied to the embodiment of FIG. 1 only, the device can be applied to any compressing element of embodiments 1-4 or 7.

(41) The device connected to the compressing element 102 comprises presser 108.

(42) Presser 108 includes a first and a second arm 110, 111, a mass 114, a locking device 115 and a blocking element 118.

(43) First arm 110 has a first end attached to roller 106 and a second end fixed to a pivot point 113.

(44) First arm 110 rotates around pivot point 113 and positions roller 106 at the contact line 13 while bobbin 1 is unwound.

(45) The second arm 111 is connected with an end to the first arm 110 and forms a given angle with the latter 110. First and second arms are fixed together at pivot point 113, so that they rotate together. Preferably the angle formed between the first and the second arms 110, 111 is acute.

(46) In the second arm, the mass 114 is inserted. Mass 114 may move along the second arm for example sliding on the same, within a given interval.

(47) The distance between a free end of the second arm and the mass may therefore vary. The moving mass has thus the function of a variator pf the force 109 applied to the compressing element. Mass 114 moves along arm 110 in the direction indicated by dotted line 122 and may be blocked in a given position by blocking element 118.

(48) In FIG. 5, blocking element 118 includes a pair of bolts.

(49) By varying the position of mass 114 along second arm 111, the force (in the direction indicated by arrow 109) that pushes roller 106 against outer surface 11 of the bobbin 1 increases or decreases.

(50) Therefore the force 109 applied by compressing element 102 (roller 106) onto the outer surface of bobbin 1 depends on the position of the slidable mass 114 on the second arm and it can be changed.

(51) Presser 108 also includes locking device 115 which allows rotation of the first and second arms 110, 111 in a single direction (either clockwise or counter clockwise around pivot point 113). Reversal of rotation is not possible due to the locking device. As depicted in FIG. 6, locking device 115 includes a toothed element 117 and a wedge 119 positioned on a bar 131 bridging first and second arm. Toothed element 117 comprises a plurality of teeth 120. Teeth and wedge may interact with each other.

(52) First and second arms 110, 111 are connected by bar 131 in which the locking device is present as in FIG. 5. The wedge 119 is positioned in front of the bar 131 so that it comes into contact with one of the teeth 120 of toothed element 117: wedge 119 may slide on teeth 120 when rotation of arms around pivot point 113 is counter-clockwise, while it locks the position of roller 106 on outer surface 11 of bobbin 1 if the rotation is clockwise. This is possible due to the shape and positioning of wedge 119 and toothed element 117.

(53) Presser 108 therefore allows compressing element 102 to apply a force 109 on the outer surface of bobbin 1 along the radius of the bobbin in a reliable manner, because the force can always be controlled, and even varied, positioning mass 114 as desired.

(54) During functioning, the free portion 12 is pulled along direction 104 by pulling device 103. The angle 105 is formed between the radius of the bobbin 14′ at the contact line 13 and the free portion of the sheet. This angle depends on the position of the pulling device, of the compressing element and the bobbin. Locally however, that is, at the contact line 13, this angle is substantially of 90 degrees due to the geometry of the compressing element 102. The intersection of the direction 104 and radius 14′ forms an angle 105 which is in the embodiments of FIGS. 1-4 of about 130 degrees, while in embodiment of FIG. 7 of about 270 degrees. This angle varies during unwinding because the size (radius) of the bobbin 1 is reduced. Preferably, this angle remains within prescribed ranges also during unwinding.