Apparatus and method for combining tobacco sheets

Abstract

The apparatus for combining tobacco sheets comprises a first shaft for carrying a first bobbin of tobacco sheet and a second shaft for carrying a second bobbin of tobacco sheet. The apparatus also comprises a splicing unit for combining an end portion of tobacco sheet from the first bobbin to a head portion of tobacco sheet from the second bobbin. The splicing unit comprises a cutting device for cutting the tobacco sheets such as to provide complementary cuts to the tobacco sheets from the first bobbin and from the second bobbin, a dispensing device for dispensing water to at least one of the tobacco sheets, and a combining device for applying force onto the tobacco sheets thereby producing a spliced tobacco sheet.

Claims

1. Method for combining tobacco sheets, the method comprising the steps of: providing a first tobacco sheet and providing a second tobacco sheet; aligning and cutting the first and the second tobacco sheets such as to provide the first and the second tobacco sheets with complementary cuts; dispensing water to at least the first or the second tobacco sheet; aligning the complementary cuts of the first and of the second tobacco sheet such that the complementary cuts rest against each other; and applying pressure onto the first and the second tobacco sheets in a cut area thereby combining the first and the second tobacco sheets and form a spliced tobacco sheet.

2. Method according to claim 1, wherein the step of cutting the first and the second tobacco sheet comprises cutting the tobacco sheets at a cutting angle in a range between about 20 degrees and about 50 degrees.

3. Method according to claim 1, wherein the step of cutting the first and the second tobacco sheet comprises cutting the tobacco sheets at a cutting angle in a range between about 25 degrees and about 40 degrees.

4. Method according to claim 1, wherein the step of cutting the first and the second tobacco sheet comprises cutting the tobacco sheets at a cutting angle of 30 degrees.

5. Method according to claim 1, further comprising the step of overlapping the first and the second tobacco sheet by more than 4 millimeters before performing the step of applying pressure.

6. Method according to claim 1, further comprising the step of overlapping the first and the second tobacco sheet by more than 6 millimeters before performing the step of applying pressure.

7. Method according to claim 1, further comprising the step of overlapping the first and the second tobacco sheet 8 millimeters before performing the step of applying pressure.

8. Method according to claim 1, wherein the step of dispensing water comprises applying water to a lower lying tobacco sheet only.

9. Method according to claim 1, wherein the step of dispensing water comprises applying water to a cutting face of a lower lying tobacco sheet only.

10. Method according to claim 1, further comprising the step of removing a cut waste end portion of the first tobacco sheet and removing a cut waste head portion of the second tobacco sheet before performing the step of applying pressure.

11. Method according to claim 1, further comprising the steps of: changing a position of a second bobbin with the second tobacco sheet to a position of a first bobbin with the first tobacco sheet and vice versa after combining the first and the second tobacco sheet; replacing the first bobbin by a further bobbin; and providing a tobacco sheet from the further bobbin for combining with the second tobacco sheet.

12. Method according claim 1, further comprising the step of introducing the combined tobacco sheet into a crimping device for crimping the spliced tobacco sheet.

13. Method according to claim 2, further comprising the step of overlapping the first and the second tobacco sheet by more than 4 millimeters before performing the step of applying pressure.

14. Method according to claim 5, wherein the step of dispensing water comprises applying water to a lower lying tobacco sheet only.

15. Method according to claim 2, further comprising the step of removing a cut waste end portion of the first tobacco sheet and removing a cut waste head portion of the second tobacco sheet before performing the step of applying pressure.

16. Method according to claim 5, further comprising the step of removing a cut waste end portion of the first tobacco sheet and removing a cut waste head portion of the second tobacco sheet before performing the step of applying pressure.

17. Method according to claim 1 to manufacture smoking articles.

Description

(1) The invention is further described with regard to embodiments, which are illustrated by means of the following drawings, wherein

(2) FIG. 1 shows an embodiment of the splicing process;

(3) FIGS. 2-4 show steps of the splicing process with the aligned tobacco sheets (FIG. 2); applied water (FIG. 3) and spliced tobacco sheets (FIG. 4);

(4) FIG. 5 shows an embodiment of the apparatus including bobbin holder and buffer unit.

(5) In FIG. 1 a first and a second tobacco sheet 3, 4 are supplied from respective bobbins 30, 40 to a splicing unit 2. The first tobacco sheet 4 is in use and is passing in a substantially straight direction through the splicing unit 2. It is further transported to tobacco sheet processing units arranged further downstream (not shown). Such processing units may for example be a crimping unit or a rod forming unit. Before tobacco sheet 4 on bobbin 40 comes to an end, tobacco sheet 3 from the second bobbin 30 is guided via guide pulley 22 and supplied to the splicing unit 2 (here from below tobacco sheet 4 in use). Both tobacco sheets 3, 4 are arranged on top of each other and aligned on a support surface 21 of the splicing unit. They are then cut under a cutting angle ? by cutting knife 20. By the cut, a clearly defined end portion of the first tobacco sheet 3 and a clearly defined head portion of the second tobacco sheet 4 is provided. A waste end portion and waste head portions may be removed after cutting the tobacco sheets 3, 4. While the cutting does not necessarily have to be performed with aligned tobacco sheets, the splicing process does. As can be seen in FIGS. 2 to 4, the tobacco sheets 3, 4 that have been cut are then aligned above each other with their cutting faces 42, 32 to overlie each other. While the cutting direction in FIGS. 2 to 4 is inversed with respect to the cutting direction of the cutting knife 20 of FIG. 1, the splicing process is the same. The cutting angle ? is in both figures about 30 degrees.

(6) With a dispensing unit 23 water is dispensed onto the lower lying tobacco sheet 4 (tobacco sheet 3 in FIG. 1 due to the different cutting direction) and onto the cutting face 42 only, as shown in FIG. 3. By a thin water layer 230 applied to one tobacco sheet only, the water may soften the material of the tobacco sheets 3, 4 at least in the area of the cutting faces 32,42 to support a good interconnection of the sheets 3, 4 in the overlapping area 35. However, the amount of water is small enough to not disintegrate the tobaccos sheets, which might complicate or hinder the formation of a joint.

(7) The so overlying and wetted tobacco sheets 3, 4 are then guided through compressing rollers 24. The sheets are compressed upon passing between the compressing rollers, which securely fixes the two cutting faces 42, 32 and the two tobacco sheets 3, 4 to each other. A short but firm connection 430 is formed as indicated in FIG. 4. To support the joint formation, a heating unit 25, for example a hot air source or a heat radiating source, is arranged downstream adjacent the compressing rollers 24. By the heat, the connection is quickly dried such that the now spliced tobacco sheet 43 may continue to be provided to further downstream arranged processing units. Since no additives for the splicing are used and since depending on the size of the overlap area 35, no significant thickening or thinning of the spliced sheet exists, a spliced tobacco sheet may entirely be used, including the connection 430. However, the overlap area 35 with the connection 430 may at a later stage also be removed to secure identical product specifications.

(8) By the splicing process according to the invention, the splicing of tobacco sheets 3, 4 may be performed in a fast and secure manner such that a tobacco sheet treatment line may continuously be operated, preferably at a constant high velocity of for example up to 200 meter per second. To further support a continuous high operation speed, a splicing process may further be automated by the provision of an automatic bobbin changer.

(9) In FIG. 5 a rotatable bobbin holder 1 is arranged upstream of the splicing unit for splicing the two tobacco sheets 3, 4. The bobbin holder 1 is provided with two bobbins 30, 40 carrying the two tobacco sheets 3, 4. Tobacco sheet 3 is continuously provided to and through the splicing unit 2 from bobbin 30.

(10) The first bobbin 30 is almost used up and has been rotated in anti-clockwise direction (indicated by arrow) by the bobbin holder away from the splicing unit 2. Upon the same rotating movement, the second bobbin 40 has been moved closer to the splicing unit 4. The tobacco sheet 4 from the second bobbin 40 is guided via guide pulley 22 into the splicing unit, where splicing may be performed. After cutting in the splicing unit, the then cut off first tobacco sheet 3 may be removed together with the bobbin 30 from the bobbin holder 1. It may be replaced by a new bobbin. As soon as the bobbin 40 comes to an end, the process may be started again.

(11) By this process a new bobbin is provided and prepared for the tobacco sheet on the new bobbin to being spliced with the tobacco sheet in use, while tobacco sheet is continuously provided to the tobacco processing line.

(12) Downstream of the splicing unit 2, an acceleration unit in the form of two acceleration rollers 5 is arranged. The tobacco sheet being passed through the splicing unit 2 may be accelerated or slowed down by the acceleration unit 5. The tobacco sheet may be continuously accelerated upon passing between the two acceleration rollers 5 in order to secure a continuous velocity of the tobacco sheet. Preferably, for the splicing process, the tobacco sheet may be decelerated or stopped by the acceleration rollers 5. After a splicing process, the spliced tobacco sheet may be accelerated again to a process velocity. A buffer unit 6 is arranged further downstream of the acceleration unit 5. The buffer unit 6 is a series of idler pulleys, where the tobacco sheet is guided around and forms loops of tobacco sheet. Some of the idler pulleys are arranged in a movable manner such as to enlarge or smaller a tobacco sheet loop in order to be able to further provide tobacco sheet material in a downstream direction, even when a supply from the splicing unit 2 or from a bobbin 30, 40 is interrupted or reduced.

(13) Downstream of the buffer unit 6 a pulling unit 7 pulls tobacco sheet out of the buffer unit to pass tobacco sheet preferably at a constant velocity to further downstream arranged tobacco sheet processing units.

(14) The bobbin holder is preferably rotated such that a new tobacco sheet may be provided from above. This simplifies the positioning of the new tobacco sheet on the upper surface of the tobacco sheet in use to be joined therewith.

(15) An arrangement of mechanical dancer and pulley rolls 10, 11 is provided on the bobbin holder 1. They are arranged next to each of the respective bobbins 30, 40. The tobacco sheets 30, 40 are guided over the rolls 10, 11 before being supplied into the splicing unit. By providing mechanical dancers and pulleys 10, 11 a controlled guiding of the tobacco sheet, as well as a constant tightening of the tobacco sheet may be achieved. This is especially favorable for tobacco sheet that tends to split or break upon large or irregular tearing or pulling forces. Especially, the rolls make up for varying pulling forces upon rotating the bobbins on the bobbin holder.

(16) The apparatus and process automatizes the feeding of tobacco sheet into a tobacco sheet treatment line. It not only allows to provide a new bobbin while tobacco sheet is continuously provided to the tobacco processing line. It also allows to splice two tobacco sheets while tobacco sheet may continuously be provided to the tobacco processing line. By this, production speed of for example a tobacco rod crimping line may be kept at a constant high level.