Method and apparatus to fold a sheet of material into a rod for an aerosol generating article

Abstract

The present invention relates to a method to fold a sheet (11) of material into a rod for an aerosol generating article, the method comprising: providing a central element and plurality of spaced apart walls (14), the spaced apart walls radially extending outwardly from the central element (12) following one another in a circumferential direction, each spaced apart wall defining an end surface (15) separated from the end surfaces of the adjacent walls; transporting the sheet of material and putting it in contact with the end surfaces of the plurality of spaced apart walls so that the sheet of material can partly fold within spaces defined between the spaced apart walls; and inserting the sheet of material into a funnel (16) to form a rod. The present invention also relates to an apparatus (10) to fold a sheet of material into a rod for an aerosol generating article.

Claims

1. A method to fold a sheet of material into a rod for an aerosol generating article, the method comprising: providing a central element and plurality of spaced apart walls, the spaced apart walls radially extending outwardly from the central element and following one another in a circumferential direction, each spaced apart wall defining an end surface separated from the end surfaces of the adjacent walls; transporting the sheet of material and putting it in contact with the top surfaces of the plurality of spaced apart walls so that the sheet of material partly folds within spaces defined between the spaced apart walls; and inserting the sheet of material into a funnel to form a rod.

2. The method according to claim 1, wherein providing a plurality of spaced apart walls includes providing spaced apart walls having a dimension which decreases moving towards the funnel.

3. The method according to claim 1, wherein providing a plurality of spaced apart walls includes providing spaced apart walls having a size of the end surface in a direction perpendicular to a direction of transport of the sheet which is increasing moving towards the funnel.

4. The method according to claim 1, including the step of crimping the sheet of material before transporting the sheet of material and putting it in contact with the end surfaces of the plurality of walls.

5. The method according to claim 1, including the step of folding the sheet of material into a tubular shape.

6. Method according to claim 1, wherein the sheet of material is a polymeric sheet or a sheet of a material containing alkaloids.

Description

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

(2) FIGS. 1-3 are schematic perspective views of an apparatus to fold a sheet of material into a rod for an aerosol generating according to the invention;

(3) FIG. 4 is a schematic lateral section of another embodiment of the apparatus to fold a sheet of material into a rod for an aerosol generating according to the invention;

(4) FIG. 5 is a schematic cross section of the apparatus of FIG. 4, taken in the plane indicated with II-II in FIG. 4; and

(5) FIG. 6 is a schematic cross section of the apparatus of FIG. 4, taken in the plane indicated with I-I in FIG. 4.

(6) 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 fold a sheet 11 of material (visible in FIGS. 4-6) into a rod for an aerosol generating article (rod and aerosol generating article are not shown in the appended drawings). Preferably the sheet 11 of material is a polymeric sheet or a sheet including homogenized tobacco material.

(7) In the preferred embodiments shown in FIGS. 1-4, the sheet 11 travels from the right to the left.

(8) The apparatus 10 comprises a central element 12 with a plurality of spaced apart walls or fins 14 extending from the central element 12 circumferentially. The central element 12 and fins 14 defines substantially a star-shaped object. Central element 12 extends along a longitudinal axis 2 of the central element (see FIG. 3) from which the fins 14 depart.

(9) Further, apparatus 10 includes a funnel 16 positioned downstream the central element 12 in the direction of motion of the sheet 11 of material. Funnel 16 defines also a longitudinal axis, which substantially coincides with longitudinal axis 2 of central element 12. Funnel 16 is known in the art to produce rods of material for aerosol generating articles and not further described in detail.

(10) Funnel 16 includes an inlet or entrance 17 for the sheet 11. At the inlet, funnel has the widest cross-section. The entrance 17 of the funnel 16 faces the central element 12, perpendicularly to the axis 2.

(11) The funnel 16 and the central element 12 are substantially coaxial.

(12) In the embodiment shown in FIGS. 1-3 there are eight spaced apart walls 14, whereas in the embodiment shown in FIGS. 4-6 there are four spaced apart walls 14. In a further preferred embodiment not shown there are ten spaced apart walls 14.

(13) The spaced apart walls 14 have a dimension which is decreasing moving towards the funnel 16. The dimension is the dimension along the radial direction of the wall, calculated in the following: the decreasing dimension is the distance perpendicularly to the axis 2 between the axis itself and the endmost point of the wall 14. This distance decreases from the beginning of the central element till the end of the central element facing funnel 16.

(14) Each wall 14 defines an end surface 15 separated from the end surfaces 15 of the adjacent walls 14. End surfaces of adjacent walls do not touch. In this way, between two adjacent spaced-apart walls, an “empty space” 3 is defined.

(15) The spaced apart walls 14 have a size of the end surface 15 taken in a direction perpendicular to a direction of transport of the sheet 11 which is increasing moving towards the funnel 16. This can be clearly seen for example in FIG. 1.

(16) The walls 14 are thinner on the point where the sheet 11 meets the apparatus 10, and become broader after.

(17) As shown in FIG. 4, a tangent 5 to the internal surface 18 of the funnel 16 substantially coincides with a tangent to the end surface 15 of a spaced apart wall 14. The tangent 5 is represented with a dotted line passing through the end surface 15 and internal surface 18 of the funnel.

(18) The apparatus 10 further comprises a conical element 20 positioned on a side of the central element 12 opposite to the funnel 16. Conical element is positioned with a basis of the cone substantially perpendicular to longitudinal axis 2.

(19) The conical element 20 has a diameter which increases towards the central element 12.

(20) The conical element 20 and the funnel 16 are substantially coaxial (see FIG. 4), so that the axis of the conical element is also longitudinal axis 2. Conical element 20 is preferably a truncated cone and defines two opposite bases 31, 32 which are preferably perpendicular to the longitudinal axis 2.

(21) With reference to the operation of the apparatus 10, the end surfaces 15 of the spaced apart walls 14 create contact lines on an incoming sheet 11 which is forced to fold into a tubular shape. The travelling direction of the sheet 11 is along the longitudinal axis 2 towards the funnel.

(22) These contact lines form a “virtual” right circular frustum of a cone having a decreasing diameter along the direction into which the sheet 11 is pulled, that is, along the longitudinal axis 2 towards the funnel 16.

(23) The empty spaces 3 defined between the end surfaces 15 of the walls 14 in contact with the sheet 11 force the sheet 11 to fold in a quite controlled way between the walls 14 of the apparatus 10 (there is an even distribution of folds or corrugations forming in the empty spaces). This is due to the decrease in volume of the empty spaces along the longitudinal axis 2.

(24) This folding occurring before the sheet 11 enters into the funnel 16 adds consistency and control to the way the sheet 11 folds on itself in the funnel 16. The sheet of material 11 therefore “experiences” the whole apparatus 10 as a truncated right circular cone which has a diameter which decreases along the direction of travel of the sheet 11, which coincides with the longitudinal axis 2. The sheet 11 before entering the funnel has already a folded conical shape.

(25) This is further enhanced by the presence of the conical element 20. This conical element meets the incoming sheet 11 before the walls 14, which is the first element contacted by the sheet 11.

(26) As shown in FIGS. 4-6, a cone can be formed considering an enveloping surface connecting the end surfaces 15 of all spaced apart walls 14. With this enveloping surface, a truncated cone is formed (see FIG. 4). The truncated cone defined by the conical element 20 and the truncated cone formed by the enveloping surface have the same axis 2. This axis is in the center axis of the tubular shape of the incoming sheet 11.

(27) The base 32 of the conical element 20 has a diameter equivalent to or larger than the diameter of the enveloping surface at its “virtual” base facing base 32, so that the incoming sheet 11 which is in tubular shape has, when leaving the conical element 20, an equivalent diameter than the enveloping surface.

(28) In this way, the sheet 11 is forced to enter in contact with the walls 14 with a slight slope, while preventing the sheet 11 to be damaged when entering in contact, at high speed, with the small end surfaces 15 of the walls 14.

(29) In FIG. 4, a straight line is drawn connecting the inner surface 18 of funnel 16 and base 32. It is shown that the walls extend beyond the straight line 22: for this reason contact is ensured contact between sheet 11 and the walls 14.

(30) The walls 14 are provided at the end surfaces 15 with a bevel 24, which allows avoiding shredding of the incoming sheet 11.

(31) In FIG. 5 folds of the sheet 11 are shown, which are formed and kept between walls 14. The folds of the sheet are forced to remain between two adjacent walls because, as the sheet 11 is pulled, and the walls 14 are extends beyond straight line 22, the sheet is substantially “compressed” against the surfaces 15.

(32) In FIG. 6 folds which are almost gathered are depicted, as space between walls 14 decreases. Almost the same quantity of folds in each space is achieved.

(33) In further embodiments (not shown), in order to change the shape of the sheet 11 from planar to tubular, it is possible to use a suitable apparatus before the apparatus 10 according to the invention, which folds the sheet 11 into a tubular shape.

(34) Furthermore, a mandrel (not shown) can be put in the center of the apparatus 10 in order to introduce specific components (flavour, material, etc.) in the center of the folded sheet 11.

(35) In general, according to the invention, a method to fold a sheet 11 of material into a rod for an aerosol generating article comprises the steps of: providing the device above described having the plurality of spaced apart walls 14, each defining the end surface 15 separated by the end surfaces 15 of the adjacent walls 14; transporting the sheet 11 of material and putting it in contact with the end surfaces 15 of the plurality of walls 14 so that the sheet 11 can partly folds within the spaces between the walls 14; and inserting the sheet 11 into the funnel 16 to form the rod.

(36) In other words, the method and apparatus 10 of the invention provide a series of spaced contacting edges (i.e. the end surfaces of the walls 14) contacting the sheet 11, and between these edges empty spaces are formed which give room for the folds of the sheet to freely arrange. The space between the contacting edges becomes narrower and narrower along the longitudinal axis 2 of the apparatus 10. In a non-depicted embodiment of the invention, the walls are parallel to each other, forming a plurality of parallel end surfaces.