Method and apparatus for manufacturing a crimped sheet of material

Abstract

The present invention relates to an apparatus (100) for crimping a sheet of material (6), the apparatus comprising: a first (9) and a second (10) facing crimping rollers defining a first (1) and a second (22) rotational axis, respectively, the first and second axis being parallel to each other, wherein at least one of the first and second crimping roller includes a plurality of corrugations; an angle changing device, the angle changing device being adapted to change a crimping angle (11) formed between a fixed reference plane (12) and a movable plane (13) containing the first and the second rotational axis.

Claims

1. Apparatus for crimping a sheet of material, the apparatus comprising: a first and a second facing crimping rollers defining a first and a second rotational axis, respectively, the first and second axis being parallel to each other, wherein at least one of the first and second crimping roller includes a plurality of corrugations; an angle changing device, the angle changing device being adapted to change a crimping angle formed between a fixed reference plane and a movable plane containing the first and the second rotational axis.

2. The apparatus according to claim 1, wherein the fixed reference plane is a horizontal or a vertical plane.

3. The apparatus according to claim 1, wherein the angle changing device is adapted to rotate the first roller around the second rotational axis of the second roller so as to change the crimping angle.

4. The apparatus according to claim 1, wherein the first and the second rollers are adapted to be rotated around the first and second rotational axis, respectively, by means of a first and a second motor.

5. The apparatus according to claim 1, including a wheel rotatable around the first rotational axis, the first and second roller being attached to the wheel so that a rotation of the wheel determines a rotation of the second roller around the first roller changing the crimping angle.

6. The apparatus according to claim 1, including a distance changing device adapted to change a distance between the first and the second roller.

7. The apparatus according to claim 6, wherein the distance changing device includes an arm on which the first or second roller is attached to and a pivot point, and wherein the distance changing device is adapted to rotate the arm around the pivot point so that the distance between the first and second roller can be changed.

8. A method for crimping a sheet of material, wherein the method includes: feeding a substantially continuous sheet of material to a set of crimping rollers, the set of rollers comprising a first roller and a second roller defining a first and a second rotational axis, respectively, at least one of the first or second roller including a plurality of corrugations; selecting a crimping angle formed between a fixed reference plane and a movable plane containing the first and the second rotational axis; and crimping the substantially continuous sheet to form the crimped sheet by feeding the substantially continuous sheet between the first and second rollers in a longitudinal direction of the substantially continuous sheet such that the corrugations of the first or second rollers apply a plurality of crimp corrugations to the substantially continuous sheet of material.

9. A method of manufacturing an aerosol-generating article component, the method comprising the steps of: manufacturing a crimped sheet according to claim 8; gathering the crimped sheet to form a continuous rod; and cutting the continuous rod into a plurality of rod-shaped components, each rod-shaped component having a gathered crimped sheet formed from a cut portion of the crimped sheet, the crimp corrugations of the crimped sheet defining a plurality of channels in the rod-shaped component.

10. The method according to claim 8, wherein the sheet of material is one of: a homogenized tobacco sheet, a plastic sheet or a sheet including cellulose.

11. The method according to claim 8, wherein the sheet of material defines a first and a second surface, and wherein the method includes the step of changing a length in the longitudinal direction of a portion of the first or second surface in contact with the first or the second roller.

12. The method according to claim 11, including the step of changing a length in the longitudinal direction of a portion of the first surface in contact with the first roller and a length in the longitudinal direction of a portion of the second surface in contact with the second roller at the same time.

13. The method according to claim 8, including the step of rotating the first crimping roller around the second rotational axis of the second crimping roller.

Description

(1) Further advantages of the invention will become apparent from the detailed description thereof with non-limiting reference to the appended drawings:

(2) FIGS. 1a-1d are schematic lateral views of an apparatus for manufacturing a crimped sheet of material in different positions of the neighbouring first and second crimping rollers;

(3) FIGS. 2a-2b are schematic lateral views of a first possible embodiment for a driving mechanism for rotating a set of crimping rollers with respect to each other in two different positions; and

(4) FIG. 3 is a schematic lateral view of a second possible embodiment for a driving mechanism for rotating a set of crimping rollers with respect to each other, comprising a possible mechanism for varying the distance between the crimping rollers.

(5) In FIGS. 1a-1d, a schematic lateral view of an apparatus 100 for manufacturing a crimped sheet of material is shown in different positions. The apparatus 100 includes two crimping rollers 9, 10. In particular, different crimping angles 11—as better defined below—are realised by an appropriate positioning of the two opposing crimping rollers 9, 10 with respect to each other, where the crimping angle 11 does not only vary with respect to the magnitude of the angle, but also with respect to the direction of the angle.

(6) The apparatus 100 is adapted to crimp a sheet of material 6 which is supplied by means of a first coil, namely a supply coil 8. The sheet of material defines a transport direction 4 (indicated with an arrow in the figures) towards the crimping rollers 9, 10. With respect to the transport direction, the supply coil is located upstream the rollers. Apparatus 100 further includes a receiving coil 7 located downstream the rollers 9, 10. On the supply coil 8, an “endless” sheet of a flat and thin layer of material 6 to be crimped using the pair of crimping rollers 9, 10 is provided. The layer of material 6 may be a homogenised tobacco sheet including plant material or a plastic sheet or a cellulose-type sheet, on which some type of tobacco-like flavour compound may be applied. It is to be understood that the sheet of material 6 that is wound up on coil 8 is strictly speaking not endless, of course. However, the overall length of the sheet of material 6 can be several hundred metres and is therefore much longer than its width. Furthermore, it is possible that a handover mechanism between two consecutive supply coils 8 (not shown) is provided so that a continuous crimping process will be possible. Of course, this would imply an appropriate handover mechanism for the receiving coil 7 as well (also not shown).

(7) The sheet of material 6 that is coiled down from the supply coil 8 and enters the “main part” of the apparatus 100, where the processing of the sheet of material 6 is performed by means of first and second roller 9, 10.

(8) For processing, the first roller 9, the second roller 10 or both rollers 9, 10 are provided with a surface structure, for example including a plurality of ridges (not visible in the drawings). Preferably, both rollers 9, 10 are provided with a surface structure, where the surface structures are designed in a corresponding way, so that the ridges on the first roller 9 will at least partially interleave into corresponding, neighbouring troughs of the second roller 10 and vice-versa. First and second roller 9, 10 each defines a rotational axis 1, 22 (visible in FIG. 1a), named first and second rotational axis, around which they are adapted to rotate. Preferably, rollers 9, 10 are substantially cylindrical and the rotational axis is the axis of the cylinder.

(9) The processing of the layer of material 6 is mainly done in a nip 5 which is formed between the first roller 9 and the second roller 10 by placing the two rollers 9, 10 at a certain distance. The distance between the two rollers 9, 10 may be fixed or may be variable, as detailed below with reference to the embodiment in FIG. 3. The width of the nip 5 is chosen to be roughly in the range of the thickness of the entering sheet of material 6. The width of the nip 5 is usually defined as the smallest distance to a neighbouring surface portion of the other roller 9, 10 in a direction that is essentially perpendicular to the surface portion in question. Depending on the current necessities of the processing process, the width of the nip 5 is typically slightly smaller than the thickness of the entering sheet of material 6 so that the entering sheet of material 6 is slightly compressed in the nip 5. Thus, a traction force can be applied to the flat sheet of material 6 by the rollers 9, 10. For achieving this, the two rollers 9, 10 are driven by a motor (not shown), presently the first roller 9 in a counter-clockwise direction and the second roller 10 in a clockwise direction, so that the sheet of material 6 is transported from the supply coil 8 towards the collecting coil 7.

(10) However, a processing of the sheet of material 6 is not only performed in the nip 5 itself, but also an additional processing is done on a surface section 2 of one of the rollers 9, 10 ahead of the nip 5 (seen the transport direction 4 for of the sheet of material 6), and furthermore preferably also in another surface section 3 after the nip 5 on one of the rollers 9, 10 as well. It is to be noted that this processing is preferably only performed on one side of the sheet of material 6 and is mainly effectuated under the influence of the tension that is imposed on the sheet of material 6. However, by these surface sections 2, 3, a possibly significantly prolonged processing time can be achieved. The surface section 2, 3 are those portions of surfaces of the first and second roller which are in contact with the sheet 6 while the sheet is crimped. Indeed, the extent of this surface, either 2 or 3, can vary depending on the angle 11.

(11) The thus processed sheet of material 6 leaves the processing part of the apparatus as a crimped sheet of material and is wound up on the collection coil 7. The collection coil 7 is preferably actively driven to be able to generate a pulling force, and the supply coil 8 preferably has to be driven as well or at least a (preferably variable) braking force has to be applied to the supply coil 8 so that a sufficient tension on the sheet of material 6 is present.

(12) In the crimping apparatus 100 according to the present invention is possible to vary the sizes, that is, the length, of the surface sections 2, 3 ahead and after the nip 5 by a simple adjustment process, without any need for rebuilding the apparatus. This way, the processing time of the sheet of material 6 to be processed can be varied in a broad range without the necessity to change the processing speed (advancement of the sheet of material 6 in transport direction 4 per unit time; this goes linearly with the rotation speed of the first and second roller 9, 10). This can be achieved by varying the crimping angle 11, as can be seen by comparing the different settings of the crimping apparatus 100 in the different figures FIGS. 1a-1d. The crimping angle 11 is indicated in the FIGS. 1a-1d as delimited by two dashed lines.

(13) The crimping angle 11 is defined as the angle between a fixed reference plane, presently a vertical plane 12, and a moving plane 13 that is defined by a plane passing through or containing the two rotational axes 1, 22 of the two rollers 9, 10 in their respective current position. The fixed plane passes through the first rotational axis 1.

(14) As can be seen from FIGS. 1a-1d, in FIG. 1a the vertical plane 12 and the moving plane 13 are parallel to each other so that the crimping angle 11 is 0°. Here, the surface sections 2, 3 ahead and after the nip 5, where a contact between the sheet of material 6 and one of the rollers 9, 10 exists, are minimal in size. It should be noted that by an appropriate placement of the collecting coil 7 and the supply coil 8, these “additional surfaces sections” 2, 3 can be reduced to essentially 0, at least at a certain diameter of the collecting coil 7 and supply coil 8, unless some horizontal movement of the respective coils is foreseen, or additional guiding rollers (presently not shown) are employed. Of course, by arranging the collecting coil 7, the supply coil 8 and possibly additional guiding rollers (if present) appropriately, one can realise surface sections 2, 3 of a significant size as well, even if the crimping angle 11 is set to 0°.

(15) In FIG. 1b, the crimping angle 11 is set to 45° in a clockwise direction. Therefore, the lower side of the sheet of material 6 is “pre-treated” (that is prior to the processing done by the nip 5) in surface section 2 ahead of the nip 5 through a contact with the second roller 10. After the nip 5, the already (partially) crimped layer of material is “post-treated” on its upper side through a contact with first roller 9 in surface section 3 after nip 5.

(16) By setting the crimping angle 11 at approximately the same magnitude (that is, circa 45°), but in the opposite direction (counter-clockwise), as it is done in FIG. 1c, the “pre-treatment phase” and the “post-treatment phase” of the sheet of material 6 are sort of interchanged. Therefore, in surface section 2 ahead of the nip 5, the upper side of the sheet of material 6 will be pre-treated by a first roller 9, while post-treatment will take place in surface section 3 after the nip 5 by a contact of the lower side of the already (partially) crimped layer of material with second roller 10.

(17) In FIG. 1d, the magnitude of the crimping angle 11 is even further increased over the position according to FIG. 1c. Now, the crimping angle 11 is 135° in magnitude, in a counter-clockwise direction. As can be seen from FIG. 1d, the size of the surface section 2, 3, and therefore the duration of the pre-treatment phase as well as the duration of the post-treatment phase is significantly increased. It is noted again that this significant increase of the pre-treatment time and the post-treatment time does not necessitate a change in processing speed of the sheet of material 6, that is the movement of the sheet of material 6 in transport direction 4 per unit time. Instead, this can be done by setting the crimping angle 11 to an appropriate angle (not only the four discreet angles according to the FIGS. 1a-1d, but also an indefinite number of other angles).

(18) As clear from the figures, the first roller 9 substantially “rotates” around the second roller 10.

(19) In FIGS. 2a-2b, an embodiment of an apparatus 200 for realising an arrangement of two rollers 9, 10 that show a variable crimping angle 11 is shown a schematic lateral view.

(20) The rollers 9, 10 are rotatably attached to a couple of plates 14 (one on each end of rollers 9, 10), where in FIGS. 2a-2b only one of those plates 14 is shown. The plates 14 can be rotated using a stepper motor 15, where the stepper motor 15 is driving an external screw thread 16 that combs into a corresponding arrangement of teeth 17, which are arranged along the outer circumferential surfaces of plates 14 (in FIGS. 2a-2b only part of the teeth 17 are shown).

(21) When rotating the external screw thread 16, different angular positions of the plates 14 and thus different crimping angles 11 can be easily realised. For brevity, only two distinct positions of plates 14 and therefore of crimping angles 11 are shown in comparison. Namely, in FIG. 2a crimping angle 11 is set to 0° (both the reference plane 12 and the movable plane 13 are horizontal; compare to FIG. 1a), while in FIG. 2b the crimping angle 11 is set to 45°.

(22) Only for completeness, it should be mentioned that instead of a stepper motor 15 different actuation means can be employed as well. It is not only possible to use an “automated means”, but also a hand crank or the like may be used as well.

(23) In FIG. 3, a lateral side view of an additional embodiment of an apparatus 300 including a mechanical arrangement of two rollers 9, 10 is shown, where the distance between the two rollers 9, 10 can be varied in an easy way, so that the width of the nip 5 can be adapted for varying sheets of material 6 to be crimped by the apparatus.

(24) The presently shown embodiment of the apparatus 300 is similar to the apparatus 200 of the embodiment that is shown in FIGS. 2a-2b in that a pair of plates 14 that can be rotated by means of a worm gear type actuator 16, 17 is employed.

(25) The second roller 10 is “directly” attached to the plate 14 in a rotatable away.

(26) For being able to vary the distance between the first and the second roller 9, 10, the first roller 9 is rotatably arranged on a first leg of an L-shaped lever 18. The lever is rotatably attached to the plates 14 by means of a pivot point 19. While the first roller 9 is arranged on a first leg of the lever 18, the second leg of the lever is attached to an actuator 20 via a driving rod 21 that can be driven back and forth by the actuator 20. This back-and-forth movement of the actuator rod 21 (initiated by actuator 20) is translated through the pivoting movement of lever 18 around pivot point 19 into a variation of the distance between the first and second roller 9, 10 and thus into a variation of the width of nip 5.

(27) It is to be noted that the embodiments shown are presently given for illustrative purposes and are not meant to be limiting the scope of the invention in any case. In particular, it is also possible to combine certain features of the certain embodiments given in a way that is obvious to a person skilled in the art.