METHOD AND APPARATUS TO FORM A ROD FOR AN AEROSOL GENERATING ARTICLE FROM A SHEET OF MATERIAL

Abstract

The present invention relates to a method to form a rod for an aerosol generating article from a sheet of material (11), the method comprising the steps of: crimping the sheet of material (11); flattening the crimped sheet of material (11) by forcing it to contact a sliding edge, transversally arranged with respect to a feed direction of the sheet of material (11); giving a substantially tubular shape to the flattened sheet of material (11); and forming the rod with the so-shaped sheet of material (11). The present invention also relates to an apparatus to form a rod for an aerosol generating article from a sheet of material (11).

Claims

1-16. (canceled)

17. A method to form a rod for an aerosol generating article from a sheet of material, the method comprising the steps of: crimping the sheet of material; flattening the crimped sheet of material by forcing it to contact a sliding edge, transversally arranged with respect to a feed direction of the sheet of material, including transporting the crimped sheet of material and putting it in contact with the sliding edge so that the sheet of material at least partly unfolds or extends; giving a substantially tubular shape to the flattened sheet of material; and forming the rod with the so-shaped sheet of material.

18. The method according to claim 17, wherein the sliding edge is included in a substantially planar sliding surface.

19. The method according to claim 18, wherein the substantially planar sliding surface is a textured surface.

20. The method according to claim 17, wherein in the step of flattening the crimped sheet of material by forcing it to contact a sliding edge, transversally arranged with respect to a feed direction of the sheet of material, the sheet of material is tensioned.

21. The method according to claim 19, wherein the step of giving a substantially tubular shape to the flattened sheet of material includes folding the flattened sheet of material against a substantially cylindrical surface.

22. The method according to claim 21, wherein the substantially cylindrical surface is connected to the substantially planar sliding surface.

23. The method according to claim 17, wherein the step of forming the rod with the so-shaped sheet of material includes inserting the sheet of material into a funnel to form the rod.

24. The method according to claim 17, wherein the sheet of material is a polymeric sheet or a sheet of a material including alkaloids.

25. The method according to claim 17, wherein the sheet of material has a thickness comprised between about 0.2 millimetres and about 1.0 millimetre.

26. Apparatus to form a rod for an aerosol generating article from a sheet of material, the apparatus comprising: a crimping device for crimping the sheet of material; a funnel portion for forming the rod; a substantially planar sliding surface comprising a sliding edge, transversally arranged with respect to a feed direction of the sheet of material, wherein the sliding edge is placed between the crimping device and the funnel portion, so that the crimped sheet of material contacts the sliding edge before entering the funnel portion, wherein the substantially planar sliding surface forms an angle comprised between about 10 and about 70 with respect to the feed direction; and a tubular surface downstream the sliding edge in the feed direction to fold the sheet into a cylindrical shape.

27. The apparatus according to claim 26, wherein the substantially planar sliding surface is a textured surface.

28. The apparatus according to claim 26, wherein the substantially cylindrical surface is connected with the substantially planar sliding surface.

29. The apparatus according claim 26, wherein the crimping device includes crimping rollers.

Description

[0056] Further advantages of the invention will become apparent from the detailed description thereof with no-limiting reference to the appended drawings:

[0057] FIG. 1 is a schematic lateral view of an apparatus according to the invention to form a rod for an aerosol generating article from a sheet of material;

[0058] FIGS. 2-4 are schematic perspective views of a portion of the apparatus of FIG. 1;

[0059] FIG. 5 is a schematic lateral view of the apparatus portion of FIGS. 2-4; and

[0060] FIGS. 6-8 are schematic cross sections of the apparatus portion of FIG. 4, taken in the planes indicated with I-I, II-II, III-III in FIG. 4, respectively.

[0061] With reference to the figures, an apparatus according to the present invention is represented and indicated with reference number 10, the apparatus 10 being suitable to form a rod (not shown in the figures) for an aerosol generating article (also not shown) from a sheet 11 of material (schematically depicted with a curved line in FIGS. 6-8). Preferably, the sheet 11 of material is a polymeric sheet made of PLA. Preferably, the sheet of material has a thickness comprised between about 0.3 millimetres and about 0.6 millimetres.

[0062] With reference to FIG. 1, the apparatus 10 comprises a crimping device 20 for crimping the sheet 11 of material and a funnel portion 30 for forming the rod. The crimping device 20 and the funnel portion 30 are known in the art and not further detailed below. The crimping device 20 includes crimping rollers (not shown in the figures) and the funnel portion 30 includes a funnel 32, wherein the sheet 11 is compressed into a rod. The sheet of material is transported along a feed direction F and it is first crimped in the crimping device 20, then processed as detailed below and then enters in the funnel portion 30 where it is compressed or folded into a rod. After passing through the crimping device 20, the sheet 11 includes a plurality of corrugations (not depicted in the drawings), usually including a ridge/grooves structure. These corrugations are substantially folds in the sheet.

[0063] The apparatus 10 also comprises a device 50 having a sliding edge 40. The device 50 is positioned between the crimping device 20 and the funnel portion 30, so that the crimped sheet 11 of material going from the crimping device 20 to the funnel portion 30 contacts the sliding edge 40 before entering the funnel portion 30.

[0064] The sliding edge 40 is transversally arranged with respect to the feed direction F of the sheet 11 of material. In FIG. 1, the sheet 11 of material goes from the right to the left, according to the direction of the arrow representing feed direction F.

[0065] The device 50 includes a substantially planar sliding surface 42 comprising the sliding edge 40. Preferably, the substantially planar sliding surface 42 is a textured surface. As shown in FIG. 5, the substantially planar sliding surface 42 forms an angle 3 with respect to the feed direction F. Preferably, the angle 3 is comprised between about 10 and about 70, more preferably is comprised between about 20 and about 60, and even more preferably is comprised between about 30 and about 50. Preferably, the feeding direction is a horizontal direction.

[0066] Furthermore, the device 50 includes a substantially cylindrical surface 44, which is provided between the sliding edge 40 and the funnel portion 30. The substantially cylindrical surface 44 is provided for giving a substantially tubular shape to the sheet 11 of material before it enters the funnel portion 30. The funnel 32 and the substantially cylindrical surface 44 are substantially coaxial, so that the sheet 11 of material is easily inserted into the funnel 32.

[0067] The substantially cylindrical surface 44 is connected with the substantially planar sliding surface 42 and preferably the two surfaces 42, 44 are formed in a single piece. Preferably the two surfaces are surfaces of an integral piece.

[0068] The device 50 including the sliding edge and the sliding surface comprises a body having front part 52, two side parts 54, and an inside part 56, better visible in FIG. 3. The body has a longitudinal axis, which corresponds to the feed direction F, and it is preferably substantially symmetrical with respect to the feed direction. Preferably, the longitudinal axis of the body of the device 50 is horizontal. Preferably, the body is an integral body, so that the front, sides and inside parts 52, 54, 56 are portions of the same body connected to each other.

[0069] In the following description, the sheet 11 of material moves along a horizontal feed direction F.

[0070] The front part 52 of the device 50 is the part that is the closest to the crimping device 20, from which the incoming sheet 11 arrives.

[0071] The front part 52 is placed above the incoming sheet 11. In other words, an upstream part of the device 50 is placed above the sheet 11.

[0072] The front part 52 includes the substantially planar sliding surface 42 which is substantially planar and forms the angle 3 with respect of the horizontal plane of the incoming sheet 11 or with respect to the feeding direction F.

[0073] In the preferred embodiment shown in the figures (in particular see FIG. 2), the planar sliding surface 42 substantially has a triangular shape including three vertexes 152, 252, 253. One 152 of the vertexes is in the bottom area of the front part 52 and the two other vertexes 252, 253 are in the upper area of the front part 52, which is the contact area where the sheet 11 begins to contact the device 50. The two vertexes 252, 253 are substantially placed at the same height and the sliding edge 40 is defined between them. Thus one side of the triangular shape of the sliding surface is the sliding edge 40. Other two sides 53, 53 are defined by edges connecting vertexes 152 and 252 as well as vertexes 152 and 253.

[0074] The front part 52 is placed above the sheet 11, i.e. the sheet 11 contacts and passes under the front part 52.

[0075] The two side parts 54 have similar shape, one being the symmetrical of the other according to a vertical plane passing through the feed direction F of the sheet 11. The two side parts extend at opposite sides of the front part surface for a portion along the feed direction F and are placed at the two sides of the inside part 56 for an additional portion along the feed direction F. The two side parts 54 keep the sheet converging towards the inside part 56.

[0076] The side parts 54 extend along the longitudinal axis of the device 50. Each side part 54 includes a curvy surface 154. The two curvy surfaces meet each other at their farthest point from the contact area of the front part 52. The curvy surfaces are tilted with respect to both a horizontal plane parallel to the feed direction and to a vertical plane. The two curvy surfaces form a converging element for the sheet towards the inside part. The two curvy surfaces are connected to the front part 52, and in particular each of them extends from one of the two sides 53, 53 of the triangular shape defined by the front part 52. Each curvy surface 154 then extends along the feed direction F towards the funnel portion 30 and in their extension the curvy surface rotates so that it becomes more and more horizontal.

[0077] In a lateral section taken along a plane parallel to the feed direction, each side part 54 defines a bottom curve 254. The bottom curve 254 is defined as a lowermost curve obtained sectioning the side part defined with a vertical plane. As shown in FIGS. 2 and 5, the bottom curve 254 of each side part 54 is substantially a vertically monotone decreasing function along the feed direction F of the sheet 11, decreasing of a predetermined vertical height along its extension.

[0078] The inside part 56 includes a portion of a horizontal tube surface having a longitudinal axis which is parallel to the feed direction F of the sheet 11. The substantially cylindrical surface 44 is defined in this horizontal tube surface.

[0079] The inside part 56 thus includes a surface that has the shape of the portion of an inner surface of a horizontal tube which is cut by a plane making an angle comprised between about 10 and about 70 with respect of the feed direction F of sheet F, for example with respect to a horizontal plane. Therefore, the inside part at the beginning of its extension includes a small portion of a cylindrical surface, and at its end it includes a whole closed cylindrical surface. From its beginning as a portion of cylindrical surface till it becomes closed, the inside part is connected at its two sides to the side parts. Therefore, the sheet 11 which comes into contact with the inside part coming from the front part, contacts an inside concave surface given by the portion of cylindrical surface and two convex surfaces given by the two curvy surfaces; the convex surfaces extend each from a side of the concave portion of cylindrical surface. The curvy convex surfaces form lateral wings to the portion of cylindrical surface and push the sheet towards the latter.

[0080] The horizontal tube (cut by a plane) formed in the inside part has a diameter which is substantially equal to the vertical decrease of the bottom curve 254 of the side part surface 54, that is, the diameter of the horizontal tube is preferably equal to the difference between the vertical ordinates of the bottom curve 254 at the beginning of the body 50 and at the end of the body 50.

[0081] The entrance zone of the portion of horizontal tubewhere the incoming sheet 11 meets the portion of horizontal tubetouches the bottom area of the front part 52. The bottom area of the portion of horizontal tube touches the lowest areas of the side parts 54 of the device 50.

[0082] In the preferred embodiment shown in the figures (in particular see FIG. 2), the device 50 defines different edges, in addition to the sliding edge 40. In particular, there are two sharply formed edges, which are the two bottom curves 254, between the side parts 54 and the portion of horizontal tube of the inside part 56. There are also two edges 53, 53 formed between the front part 52 and the side parts 54. The two edges are the sides of the triangular-shaped front part.

[0083] In particular, FIG. 2 shows the device 50 from below, and the edges 53, 53, 254 can be seen. These edges 53, 254 stretch the sheet 11, the path of which is indicated by the dotted arrow P.

[0084] The described shape of the device 50 creates various effects on the flow of sheet 11 that is pulled into the device 50 by the overall machine into which the sheet 11 is processed. When started, the overall apparatus 10 pulls at high speed the sheet 11 through the crimping device so that corrugations are formed in the sheet 11. The sheet then passes through the device 50. The sheet 11 is made of flexible material so that it has a flow-like behaviour when passing into the device 50.

[0085] A first effect is that the structure of the material forming the sheet is weakened. The sheet 11 is flattened against the sliding edge 40. The sliding edge 40 unfolds the corrugations on the crimped sheet 11, thereby weakening the crimped portions of the sheet 11 when the sheet is further pulled along the edges 254 between the side parts 54 and the horizontal tube of the inside part 56.

[0086] A second effect is that the sheet 11 extends when it meets the front part 52 and the side parts 54. This extension, when done after the crimping, extends the structure of the material forming the sheet 11 which has, after the crimping, a ridges/grooves shape (or corrugated shape). This extension smoothen the ridges/grooves shape and so it helps to additionally break the structure of the material forming the sheet. This additional weakening of the material forming the sheet is done without having to increase the pressure or the depth of the crimping, and therefore without the related side effects of such increase of pressure which can damage or shred the material forming the sheet.

[0087] A third effect is that the sheet 11 gets a tubular shape inside the device 50. Such tubular shape is more compact than a planar sheet shape, and so it helps the compression process to a rod, and it is stable, which helps to reach consistency in the compression of the sheet 11 and therefore in the final product.

[0088] The surface of the device 50 in contact with the sheet material has preferably a textured surface that decreases friction between the device 50 and the sheet material.

[0089] FIG. 5 shows the lower profile of the device 50, corresponding to bottom curve 254 for the middle part where the side parts extend. Three different sections of the lower profile of the device 50 are substantially rectilinear and lie at three respective different angles 1, 2 and 3 with respect to the feed direction F. The angle 3 has been described above, while the angle 2 is preferably comprised between about 5 and about 30 and the angle 1 is preferably comprised between about 10 and about 20.

[0090] The sheet 11 of material first passes over the section having the angle 3, then over the section having the angle 2 and finally over the section having the angle 1.

[0091] The angles 2 and 3 formed by the device 50 may provide a gradual transition and effective stretching, while the angle 1 is preferably relatively small to avoid sheet damage while the sheet 11 is entering in the portion of inside part 56 which form a closed cylindrical surface.

[0092] FIGS. 6-8 shows three cross sections of the device 50, taken in the planes indicated with I-I, II-II, III-III in FIG. 4, respectively. The plane I-I is located in the above-mentioned section having the angle 3, the plane II-II is located in the above-mentioned section having the angle 2 and the plane III-III is located in the above-mentioned section having the angle 1.

[0093] FIGS. 6-8 also shows the sheet 11 of material which is flattened at the front part 52 (FIG. 6) and then enters the inside part 56, wherein progressively takes the substantially tubular shape (FIGS. 7 and 8).

[0094] In operation, the apparatus 10 performs the following method to form a rod for an aerosol generating article from the sheet 11 of material, the method comprising the steps of: crimping the sheet 11 of material; flattening the crimped sheet 11 of material by forcing it to contact the sliding edge 40, transversally arranged with respect to the feed direction F of the sheet 11 of material; giving a substantially tubular shape to the flattened sheet 11 of material; and forming the rod with the so-shaped sheet 11 of material.

[0095] The step of flattening the sheet includes transporting the crimped sheet 11 of material and putting it in contact with the sliding edge 40 so that the sheet 11 of material at least partly unfolds and/or extends.

[0096] In the step of flattening the sheet, the sheet 11 of material is tensioned.

[0097] The step of giving a tubular shape to the sheet includes folding the flattened sheet 11 of material into the substantially cylindrical surface 44 of the device 50.

[0098] The step of forming the rod includes inserting the sheet 11 of material into the funnel 32 to form the rod.

[0099] In other words, the apparatus 10 comprises a preforming shoulder (including the sliding edge 40) which is arranged transversally to the sheet movement direction (feed direction F) and which is placed between crimping device 20 and the funnel portion 30 of the apparatus 10 itself, so that the crimped sheet 11 under tension slides over the preforming shoulder, before entering the funnel portion 30.