Method and device for producing individual portions of material in powder form The present invention relates to a method for producing individual portions of material in powder form, specifically a mass of ground, moist tobacco, the powdery material being fed in portiohs from the bottom side of a magazine into cavities provided with a movable bottom wall and movable in a closed path in which cavities the portions then are successively compressed to a predetermined volume by displacement of the movable bottom wall against a fixed counter wall during conveyance to a discharge place. The invention relates specifically to forming of so called portion packed snuff, starting from tobacco powder with a moisture content of at least 30%. The moisture content is preferably about 50% to avoid the necessity of subsequent moistening. In that case, however, there will be problems with the feeding down of the moist tobacco powder into the cavities for forming of the portions.

This problem is solved by the invention in an uncomplicated and advantageous manner in that the cavities are arranged to be moved through the mass of powdery material and the cavities are designed with at least two open sides, that is in addition to the side opposite the movable bottom wall at least one further side through which the cavities are filled at the same time as the cavities are moved a fixed distance with the open sides exposed against the powdery material in the magazine. A rapid and reliable filling of the cavities is obtained due to the fact that the cavities are filled simultaneously from two directions. It is also possible to have a third side of the cavities open, which means that the cavities have the shape of gaps between consecutive teeth, which dig themselves into the mass of tobacco powder, which enables an incomparably secure filling of the cavities.

The invention relates also to a machine for performing the method according to the invention, comprising a rotary portion forming wheel having cavities equally distributed around the periphery of the wheel, a magazine filled with powdery material, preferably a mass of ground, moist tobacco, from the bottom portion of which the powdery material is fed down into the passing by cavities, which are open radially outwards and have plungers arranged in the bottom of each cavity, which plungers during the movement of the cavities towards a discharge place are arranged to be successively displaced radially outwards during compression of the material in the cavities against a fixed, curved counter wall.

The portion forming wheel has, in order to obtain a quick and safe filling of the cavities, according to the invention, the shape of a thin, circular disk in which the cavities are arranged with at least one of the two opposite sides of each cavity in the sides of the portion forming wheel open towards the mass of the powdery material. In that way the cavities are filled in a favourable manner from two or three sides at the same time. Further, the bottom portion of the magazine has, according to a favourable embodiment of the invention, such an extension in the direction of the path of movement of the cavities that several cavities are being filled at the same time.

Other favourable embodiments of the machine according to the invention are defined by the following patent claims.

The invention is explained more in detail in the following with reference to the attached drawings which schematically show different embodiments of machines according to the invention. Figure 1 is a side view, partly in section, of a complete machine for producing portion packed snuff, Figure 2 is a longitudinal sectional view of a magazine filled with moist tobacco powder on top of a portion forming machine, Figure 3 is a plan view, partly in section of the magazine and machine shown in Figur 2, Figures 4-6 are enlarged details of the parts marked A, B and C in Fig. 2 and Fig. 3, Figure 7 is a side view, partly in section, of a double-magazine and a portion forming device with two discharge places. Figure 8 is a plan view, partly in section, of the magazine and portion forming device shown in Fig. 7, Figure 9 is a side view, partly in section, of a magazine and a vertically arranged portion forming wheel, Figure 10 is a cross sectional view of the portion forming wheel shown in Fig. 9, Figure 11 is an enlarged detail marked A in Fig. 10, Figure 12 is a plan view of the part of the vertical portion forming wheel that is located in the tobacco mass, and Figures 13 and 14 are corresponding side views of two embodiments of the horizontal portion forming wheel.

The machine shown in Fig. l for producing portion packed snuff from ground, moist tobacco mass has a bobbin 1 on which a web 2 of wrapping material, suitable for the purpose, is wound. The web is guided by guide rollers to a perforated conveying belt 3, which runs over two end rollers 4a, 4b. one of which, namely roller 4b, being driven. The belt 3 is arranged to slide over a perforated upper side of a vacuum chamber which is divided into two parts 5a, 5b. Thus, the web 2 is sucked firmly to the conveying belt 3 and follows the belt, which is amplified by a pair of press rollers 6. The machine is provided with a magazine 7 containing tobacco mass 10.

The bottom of the magazine is closed by a horizontal portion forming wheel 8 having cavities in the shape of rectangular recesses, which will be described closer in connection to Figs. 2-6. The magazine 7 is fixedly mounted on an upper support 9, which in turn is attached to a bottom support 11. The portion forming wheel 8 is rotatably mounted between said supports with the upper support 9 so designed that when the cavities move in the magazine 7 the upper sides of the cavities, and possibly also the under sides, and the radially outwards directed sides are exposed to the tobacco mass, but when the cavities move outside the magazin 7 all the sides of the cavities are closed by the two supports 9,11, with the exception of the radially outwards directed sides of the cavities being uncovered by the supports 9,11 at a discharge place. The portions compressed in the cavities by radially outwards movable plungers are transferred at the discharge place to the web 2 fed forward on the conveying belt 3, on which web the portions, in a manner known per se, are conveyed through folding guides 13, which fold the web 2 around the portions, two counter rotating longitudinal welding wheels 14, and a combined transversal sealing and cutting device provided with a transversal welding wheel 15 and as counter support and cutting means acting wheels 16, which separate individual portion packs 17.

Figs 2-6 disclose closer how filling of the cavities and compression and discharge of portions is carried out in the device shown in Fig. 1.

Figs. 2 and 3 show the magazine 7 containing the tobacco mass 10. As mentioned before, the magazine is fixedly mounted on the upper support 9. This is in turn attached to the bottom support 11, that has a mainly circular groove with a wall 18 with constant radius and a wall 19 with increasing radius, in which groove the portion forming wheel 8 is rotatably mounted, driven by a driving means not shown with a periphery speed that is equal to the speed of the conveying belt 3. The wall 18 may have a somewhat larger radius than the radius of the wheel 8 inside the magazine 7, which may give rise to a possibly safer filling of the cavities. The wheel 8 is provided with cavities 20 in the shape of radial, axial through cavities, in each of which a plunger 21 is radially movable by means of a plunger rod 22, which carries a roller 23 rolling on a fixed cam 24.

The upper support 9 has an arc-shaped opening 25 permitting exposing of the cavities 20 to the tobacco mass when the cavities are moved through the magazine. When the cavities 26 filled with tobacco mass move out from the magazine 7 the cavities slide in between the upper support 9 and the bottom support 11 which close the upper and bottom sides of the cavities and the radial wall 18 of the groove closes the remaining open side of the cavity, which wall during the movement of the cavities toward the discharge place acts as a counter surface when the plunger 21 is pressed outwards by the cam 24. When the portion of tobacco mass in a cavity 20 has been compressed to a desired volume, the wall 18 with constant radius of the groove changes to a wall 19 of the groove with increasing radius. such that the plungers 21 at displacement to the periphery of the wheel 8 push out the ready-compressed portions 27 from the cavities 20. A doctor blade 28 is arranged to scratch the ends of the plungers 21 if necessary depending on adhering portions 27. The transfer of the portions from the wheel 8 to the web 2 on the belt 3 is more clearly shown on Figs. 5 and 6, which show the positions B and C, respectively, in Fig. 2. Fig. 5 discloses with dot and dash lines the position of a portion 27 after having dropped down on the web 2.

Figs. 7 and 8 show a machine where the operations, corresponding to the operations carried out during one revolution machine in Fig. 2-6, are carried out during a half revolution. Accordingly, the machine according to Figs. 7,8 has a capacity that is double the capacity of the machine according to Figs. 2-6. Therefore it is equipped with two in opposite directions movable conveying belts 3a, and 3b and two magazines 7a and 7b, witch possibly may be combined to a common magazine. In other respects different parts in Figs. 7,8 are denoted by the same denotations as corresponding parts in Figs. 5,6.

Figs. 9,10 and 11 show a preferred embodiment of the machine according to the invention. Here the portion forming wheel 8 is mainly unchanged but arranged vertical with the upper part protruding into a magazine 7, Also here are the different parts denoted like corresponding parts of the embodiments described above. The wheel 8 is encased in a groove in a fixedly arranged casing consisting of two parts 30,31 and is driven by a shaft 32. The above mentioned plungers 21 with plunger rods 22 are driven as described above by means of rollers 23 which here roll in a track 33 acting as a cam. The compression of the portions in the cavities is carried out as before against an arc-shaped wall 18 of the groove.

The portions 27 are pushed out, at the discharge place, vertically down onto the underlying web 2 on the belt 3 guided by a folding plate 34, and the belt 3 is driven synchronized with the wheel 8, as shown most clearly in Figs. 10 and 11.

The magazine 7 may have the width shown in Fig. 10. Because the cavities 20 are open in three directions and are moving a long distance through the magazine like a saw blade or a tooth wheel an efficient filling is obtained also with a narrow magazine, especially as any kind of agitating device known per se (not shown) usually is used in the magazine for preventing clogging of the powdery material. It is suitable, however, to use a wider magazine, in which case several portion forming wheels of the type shown in Fig. 10 may be arranged side by side in a common magazine and with each a conveying belt, as indicated by dot-dash lines in Fig. 10.

The essentially new with the invention is the efficient filling of the cavities in the magazine and the possibility of an easy way to double the capacity with horizontal portion forming wheels and multiply the capacity with vertical portion forming wheels when the space is limited. The principle of filling of the cavities 20 with vertical portion forming wheels 8 is shown in Fig. 12, that shows the wheel 8 from above in the magazine. The cavities 20 with the bottom located plungers 21 (not shown) are on all sides surrounded by the powdery tobacco mass 10 until the filled cavities 26 start sliding in between the walls 30,31 of the casing. In case of a horizontal wheel 8 it may lie close to the bottom support 11, and the cavities 20 may possibly be open only upwards and radially outwards, as shown in Fig. 13. As an alternative also the bottom sides of the cavities may be open, as shown in Fig. 14, in which case the wheel 8 suitably is positioned at a small distance from the bottom support 11, such that tobacco powder can be filled from the bottom side into the cavities.

The invention is of course not restricted to the here shown and described embodiments but may be modified in different ways within the scope of the invention defined by the claims. Thus, it is possible for example to replace a circular portion forming wheel by another device movable in a closed path. Further, it is of course possible to position the portion forming wheels in any angle of inclination between horizontal and vertical position, for example to adapt the discharge of the portions to the folding plate 34 shown in Fig. 11.