Method for unwinding a bobbin of a coiled sheet and kit to unwind a sheet of material wound in a bobbin

Abstract

The present invention relates to a method for unwinding a bobbin (12) of a coiled sheet (13), the method comprising the steps of: providing a bobbin of a coiled sheet, the bobbin having a first rotation axis (17) and comprising a free portion (14) of the sheet unwound from the bobbin, the free portion (14) defining a contact line (16) as a line separating the free portion and the remaining of the coiled sheet (13); providing a roller (30) having a second rotation axis substantially parallel to the first rotation axis (17); putting the roller (30) in contact with the bobbin (12) at the contact line (16); unwinding the sheet from the bobbin (12) pulling 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 or between about 200 degrees and about 300 degrees; and while unwinding the sheet from the bobbin keeping the roller in contact with the outer surface of the bobbin. The present invention also relates to a kit to unwind a sheet of material wound in a bobbin.

Claims

1. A method for unwinding a bobbin of a coiled sheet including a homogenized tobacco sheet, the method comprising the steps of: providing a bobbin of a coiled sheet including a sheet of a material comprising a homogenized tobacco sheet, the bobbin having a first rotation axis and comprising a free portion of the sheet unwound from the bobbin, the free portion defining a contact line as a line separating the free portion and the remaining of the coiled sheet; providing a roller having a second rotation axis substantially parallel to the first rotation axis; putting the roller in contact with the bobbin at the contact line; unwinding the sheet from the bobbin pulling 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 or between about 200 degrees and about 300 degrees; while unwinding the sheet from the bobbin, keeping the roller in contact with an outer surface of the bobbin.

2. The method according to claim 1, wherein the roller moves its angular position with respect of the bobbin while unwinding.

3. The method according to claim 1, including rotating the roller in a direction opposite to a rotation direction of the bobbin during unwinding.

4. The method according to claim 1, including placing the free portion of the sheet in contact with the roller for a length equal to at least about 40% of a perimeter of the roller.

5. The method according to claim 1, including arranging a scraper between the free portion of the sheet and the remaining of the sheet coiled in the bobbin in such a way that the scraper is in contact with the sheet coiled in the bobbin.

6. The method according to claim 1, including: determining a roundness of the bobbin; selecting an unwinding velocity of the bobbin based on the determined roundness.

7. The method according to claim 1, including sensing a diameter of the bobbin.

8. A kit to unwind a sheet of material wound in a bobbin, the kit comprising: a bobbin of a coiled sheet including a homogenized tobacco sheet defining an outer surface and a free portion of the sheet unwound from the bobbin, the free portion defining a contact line as a line separating the free portion and the remaining of the coiled sheet; an apparatus including: a bobbin holder holding the bobbin rotatable around a first axis; a roller having a second rotation axis substantially parallel to the first rotation axis, the roller being in contact with the outer surface of the bobbin at the contact line; a pulling device adapted to pull the free portion of the sheet of the bobbin along an unwinding direction; wherein the roller and the pulling device are respectively positioned so that an angle between the free portion of the sheet along the unwinding direction and a radius of the bobbin at the contact line is comprised between about 110 degrees and about 150 degrees or between about 200 degrees and about 300 degrees.

9. The kit according to claim 8, wherein the roller is arranged in a angularly movable position with respect of the holder.

10. The kit according to claim 8, wherein the apparatus includes a scraper arranged between the free portion of the sheet and the remaining of the sheet coiled in the bobbin in such a way that the scraper is in contact with the sheet coiled in the bobbin.

11. The kit according to claim 8, wherein the apparatus includes a speed regulator to vary a rotation speed around the first axis of the bobbin holder.

12. The kit according to claim 8, wherein the apparatus includes a diameter sensor to determine the diameter of the bobbin.

Description

(1) Further advantages of the invention will become apparent from the detailed description thereof with no-limiting reference to the appended drawings:

(2) FIG. 1 is a schematic side view of an apparatus to unwind a sheet of material wound in a bobbin according to a comparative embodiment;

(3) FIG. 2 is a schematic side view of the bobbin of FIG. 1, wherein forces involved during unwinding the bobbin are indicated;

(4) FIG. 3 is a schematic side view of a first embodiment of an apparatus to unwind a sheet of material wound in a bobbin according to the invention;

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

(6) FIG. 5 is a schematic side view of the apparatus of FIG. 3, wherein forces involved during unwinding the bobbin are indicated;

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

(8) With initial reference to FIGS. 1 and 2, an apparatus to unwind a sheet of material 13 wound in a bobbin according to a comparative example is represented and indicated with reference number 10.

(9) The apparatus 10 is adapted to unwind the bobbin 12.

(10) For instance, the bobbin 12 can be a homogenized tobacco material bobbin. However, the invention can be applied to all industries where manufacturing processes include the unwinding of bobbins having sticky and fragile sheets, for instance, paper industry or industry using polymer sheets coiled in bobbins.

(11) The bobbin 12 shown in FIGS. 1 and 2 has a round, for example cylindrical, shape. However, the invention works fine with bobbins even when the bobbins do not have round shape.

(12) The apparatus 10 comprises a bobbin holder 20 where the bobbin 12 is placed.

(13) The bobbin holder 20 holds the bobbin 12. Preferably, a center of the bobbin holder 20 coincides with a center 17 of the bobbin 12. Preferably, the bobbin 12 is inserted in the bobbin holder 20. The bobbin holder 20 is rotatable around an axis passing through its center.

(14) The bobbin 12 is formed by the coiled sheet 13. The apparatus 10 is adapted to unwind the coiled sheet 13 of the bobbin 12, as shown in FIGS. 1 and 2.

(15) Bobbin 12 is formed by winding the sheet 13 of material, which defines a free portion 14 of the sheet 13 unwound from the bobbin 12 and defines an outer surface 15.

(16) The separation line between the free portion 14 of the sheet 13 and the remaining of the bobbin 12 is called contact line 16. Further, bobbin 12 defines a radius 18 (represented as a dotted line in FIG. 2).

(17) The comparative embodiment of unwinding apparatus 10 includes also the related set-up for unwinding the tobacco cast leaf bobbin 12 to feed a crimping machine 60, and combination of forces involved during the process of unwinding the bobbin 12.

(18) The cast leaf sheet 13 is pulled towards the feeding inlet of the crimping machine 60, and the point, transversal line (i.e. contact line 16), of detachment of the cast leaf sheet 13 from the bobbin 12 is moving depending of the adhesion between the last two layers of cast leaf sheet 13 in the bobbin 12. This point of detachment tends to be as described in FIG. 2 in terms of the combination of forces involved.

(19) The dashed forces depicted as arrows in FIG. 2 and labelled 5 and 6 are the pulling forces (with reaction), the dotted arrow 3 is the compression force and the continuous line arrow 4 is the resulting force of all forces named above.

(20) With reference to FIGS. 3, 5 and 6, a first embodiment of apparatus 110 to unwind a sheet 13 of material wound in a bobbin 12 according to the invention is represented. Sheet and bobbin are as described with reference to the comparative example and thus the same reference numerals are used.

(21) Components of the apparatus 110 which are analogous or functionally equivalent to those of the apparatus 10 are indicated with the same reference numbers and are not repeated herewith.

(22) The bobbin 12 of a coiled sheet 13 defines the outer surface 15 and a free portion 14 of the sheet 13 unwound from the bobbin 12. The free portion 14 defines a contact line 16 as a line separating the free portion 14 and the remaining of the coiled sheet 13.

(23) The apparatus 110 includes the bobbin holder 20, holding the bobbin 12 rotatable around a first rotation axis, and a roller 30 having a second rotation axis substantially parallel to the first rotation axis.

(24) The roller 30 is in contact with the outer surface 15 of the bobbin 12 and defines the contact line 16, which separate the free portion 14 from the rest of the bobbin 12, when the free portion 14 is pulled as detailed below.

(25) The roller 30 rotates in a direction opposite to a rotation direction 21 of the bobbin 12 during unwinding. In the side view of FIG. 3, the rotation direction 21 is the counterclockwise direction.

(26) The second rotation axis of the roller 30 is located substantially under the bobbin 12, near to a vertical plane including the first rotation axis of the bobbin holder 20.

(27) The roller 30 is arranged in a fixed position with respect of the holder 20. Alternatively, the apparatus 110 can comprise a position adjustment system adapted to change the position of the roller 20 with respect to the bobbin holder 20 depending on a dimension of the bobbin 12 present in the holder 20. In this case, the apparatus 110 comprises a control unit connected to the position adjustment system and adapted to command the position adjustment system to move the roller 30 towards the bobbin 12 as the dimension of the bobbin 12 reduces due to unwinding.

(28) The apparatus 110 can be advantageously used in the unwinding process currently existing just before tobacco cast leaf crimping, in the process step of unwinding/feeding of the related crimping machine. The apparatus 110 (which is substantially a rolling apparatus) is integrated in the existing system, and does not involve relevant changes in the current overall equipment set-up.

(29) The tension caused by the pulling force feeding the crimping equipment while unwinding the cast leaf in the bobbin 12, is first of all felt and converted in several portions by the roller 30 that is always in contact with the last/external layer/sheet 13 of the cast leaf in the bobbin 12, independently of the rotating speed and external diameter of the bobbin 12 (see FIG. 5).

(30) According to the invention, a method for unwinding the bobbin 12 of the coiled sheet 12 comprises the steps of putting the roller 30 in contact with the bobbin 12 at the contact line 16 and unwinding the sheet 13 from the bobbin 12 keeping the roller 30 in contact with the outer surface 15 of the bobbin 12.

(31) According to the invention, the apparatus 110 unwinds the cast leaf bobbin 12 from the outer perimeter thereof with a contact “peeling” by the roller 30. By the apparatus 110 with the roller 30 it is possible to control where the point/line of detachment occurs (i.e. the contact line 16), always in the same place if required.

(32) Adding such unwinding roller 30 that “sits” on the bobbin 12, providing a constant “peeling” point/line placement, which then enables to keep the combination of forces stable and the overall process consistent, while reducing the mechanical effort caused in the cast leaf sheet 13 in the point/line of “peeling” (i.e. the contact line 16). This also enables to control the angles related to the center 17 of the bobbin 12 as well as the point of feeding inlet of the machine while being unwind.

(33) The apparatus 110 includes a pulling device 40 of the free portion 14 of the sheet 13 in an unwinding direction.

(34) The pulling device 40 comprises a pair of rollers 42 and pulls the free portion 14 of the bobbin 12 along an unwinding direction. The distance between the pulling device 40 and the bobbin 12 depends on the type of bobbin 12, the sheet material and the speed of unwinding.

(35) During functioning, the free portion 14 is pulled along the unwinding direction by the pulling device 40. An angle is formed between the radius of the bobbin 12 and the free portion 14 of the sheet 13. This angle depends on the position of the pulling device 40, of the roller 30 and the bobbin 12. This angle varies during unwinding because the size (radius) of the bobbin 12 is reduced.

(36) The pulling device 40 is arranged so that an angle between the free portion 14 of the sheet 13 and the radius of the bobbin 12 at the contact line 16 is comprised between either about 110 degrees and about 150 degrees (embodiment of FIG. 4 described below) or between about 200 degrees and 300 degrees (embodiment of FIG. 3).

(37) The free end portion 14 of the sheet 13 is placed in contact with the roller 30 for a length equal to at least about 40 percent of the perimeter of the roller 30.

(38) The apparatus 110 includes a diameter sensor 112 to determine the diameter of the bobbin 12.

(39) The apparatus 110 can include a speed regulator (not illustrated) to vary the rotation speed around the first axis of the bobbin holder 20.

(40) The unwinding method carried out by the apparatus 110 can include determining a roundness of the bobbin 12 and selecting an unwinding velocity of the bobbin 12 based on the determined roundness.

(41) In an embodiment, the apparatus 110 include a scraper 300 arranged between the free portion 14 of the sheet 13 and the remaining of the sheet 13 coiled in the bobbin 12 in such a way that the scraper is in contact with the sheet 13 coiled in the bobbin 12.

(42) With reference to FIG. 4, a second embodiment of the apparatus 210 to unwind the sheet 13 of material wound in the bobbin 12 according to the invention is represented.

(43) Components of the apparatus 210 which are analogous or functionally equivalent to those of the apparatus 110 are indicated with the same reference numbers and are not repeated herewith.

(44) The apparatus 110 includes the bobbin holder 220, holding the bobbin 12 rotatable around a first rotation axis, and a roller 230 having a second rotation axis substantially parallel to the first rotation axis.

(45) The roller 230 is in contact with the outer surface 15 of the bobbin 12 at the contact line 16.

(46) The roller 230 rotates in a direction opposite to a rotation direction 22 of the bobbin 12 during unwinding. In the side view of FIG. 4, the rotation direction 22 is the clockwise direction.

(47) The second rotation axis of the roller 230 is located substantially beside the bobbin 12, near to a horizontal plane including the first rotation axis of the bobbin holder 220.

(48) The dashed force depicted as arrows in FIG. 5 and labelled 6 is the pulling force (with reaction), the dotted arrow 3 is the compression force and the continuous line arrow 4 is the resulting force of all forces named above. An enlargement of FIG. 5 is given in FIG. 6 where the contact line is shown, where the sheet detaches from the bobbin. The unwinding apparatus 110 is arranged to uncoil/unroll an elongated sheet 13 coiled or rolled to form a bobbin 12.

(49) By using the apparatus 110 of the invention, the occurrences of breakings of the sheet 13 decrease and the yield of the sheet material advantageously increases.

(50) Moreover, the apparatus 110 of the invention limits the heat transferred to the sheet 13. Therefore, in the case of tobacco cast leaves bobbins 12, the tobacco cast leaves are not damaged.

(51) Furthermore, the apparatus 110 of the invention allows increasing the unwinding speed of the bobbins 12.