The present invention relates to a vertical flow-wrapper comprising:

- a film-feed, which feeds the film from a reel to a forming-unit,

- a forming-tube and a forming-shoulder, which form a film into a film-tube,

- longitudinal sealing means to seal the longitudinal edges of the film-tube together,

- cross-sealing means to provide a cross-seal to the film-tube to produce individual packages and

- cutting means to separate the individual packages from the film-tube,

wherein the cross-sealing means and the cutting means are moved together with the film tube during sealing and/or cutting and are driven by a crank-mechanism, with an upper- and a lower dead center.

This vertical flow wrapper is very well known to the person skilled of the art and is used, to form a web, for example a plastic film or a paper material, into a tube from which individual packages are produced. Nowadays, these wrappers need to be highly flexible in terms of the size and shape of the package to be produced as well as the material to be used.

It was therefore the objective of the present invention to provide a vertical flow wrapper that meets these requirements.

This objective is attained by a vertical flow-wrapper comprising:

- a film-feed, which feeds the film from a reel to a forming-unit,

- a forming-tube and a forming-shoulder, which form a film into a film-tube,

- longitudinal sealing means to seal the longitudinal edges of the film-tube together,

- cross-sealing means to provide a cross-seal to the film-tube to produce individual packages and

- cutting means to separate the individual packages from the film-tube,

wherein the cross-sealing means and the cutting means are moved together with the film- tube during sealing and/or cutting and are driven by a crank-mechanism, with an upper- and a lower dead center,

wherein the distance (D) between the upper dead center of the cross-sealing means and the lower end of the tube remains identical regardless of the length of the vertical movement of the sealing means which can be altered without a rebuilding of the crank-mechanism. The disclosure made regarding this subject matter of the present invention also applies to the other subject matters and vice versa. Subject matters disclosed regarding this subject matter can be combined with other subject matters and vice versa.

The present invention relates to a flow wrapper, which comprises a film feed, which feeds the film, for example a plastic film and/or a paper material from a reel to a forming unit. This forming unit comprises a forming tube and a forming shoulder which form the plane film into a tube. Subsequently, the longitudinal edges of the tube are sealed together by longitudinal sealing means. In a next step, the tube is filled with a packaging item and cross seals are provided to the tube to produce individually closed packages which are finally cut a part, wherein the cross seal is cut apart. The flow wrapper according to the present invention is operated with a continuously or intermittently moving film and during sealing and/or cutting, the cross sealing means and/or the cutting means are moved together with the film tube.

According to the present invention, the cross sealing means and the cutting means are driven by a crank-mechanism, with an upper- and a lower dead center, which transfers a rotational movement of a motor into an up and down movement of the cross sealing and/or cutting means, wherein the distance between the upper dead center of the cross-sealing means and the lower end of the tube remains identical regardless of the length of the vertical movement of the sealing means.

Furthermore, according to the present invention, the length (x) of the package can be changed without a rebuilding of the crank-mechanism. Hence, two or more bags with a different length can be produced on the same machine without rebuilding the crank- mechanism, for example its levers.

Preferably, the inventive flow wrapper also comprises folding means, for example to form gussets at the bottom and/or at the top of the package. This folding means are preferably also attached to the sealing means.

This embodiment of the present invention has the advantage that the conditions to form the package as well as the droping distance of the items filled into the respective package remain unchanged, even though, for example the sealing time or the length of the package is changed. Particularly in case in which the lower end of the forming tube is utilized to improve the forming, particularly folding of the package, the constant distance between the lower end of the forming tube and the upper dead center is particularly important. Another preferred or inventive embodiment of the present invention is a vertical flow- wrapper, wherein the lower dead center is adjusted by altering the leverage of a lever which is part of the crank mechanism.

The disclosure made regarding this subject matter of the present invention also applies to the other subject matters and vice versa. Subject matters disclosed regarding this subject matter can be combined with other subject matters and vice versa.

According to this embodiment of the present invention, the crank mechanism comprises a lever with an adjustable leverage, for example between the part of this lever that is connected to the rotating drive, for example a motor, of the crank mechanism and the part that is directly or indirectly connected to the sealing- and/or cutting means. Preferably the ratio between the length of the lever between the connection to the rotating drive and a bearing of the lever and the length between this bearing and the connection to the sealing- and/or cutting means is altered in order to change the sealing time and/or the length of the package.

Yet another preferred or inventive embodiment of the present invention is a vertical flow- wrapper, wherein one lever of the crank mechanism is mounted on a ramp.

The disclosure made regarding this subject matter of the present invention also applies to the other subject matters and vice versa. Subject matters disclosed regarding this subject matter can be combined with other subject matters and vice versa.

According to this preferred or inventive embodiment of the present invention, one of the levers of the crank mechanism is bared on a ramp, i.e. is at no instant in time neither oriented horizontally nor vertically. Preferably, the bearing of this lever can be moved up and down the ramp in order to adjust the leverage of this lever and/or to adjust the length of the package and/or the sealing time.

According to yet another preferred or inventive embodiment of the present invention, the vertical flow-wrapper has one lever which is mounted by a floating bearing.

The disclosure made regarding this subject matter of the present invention also applies to the other subject matters and vice versa. Subject matters disclosed regarding this subject matter can be combined with other subject matters and vice versa. According to this preferred or inventive embodiment of the present invention, one lever of the crank device is mounted by a floating bearing, i.e. the bearing can move relative to the lever, for example for adjustment purposes and/or the lever moves relative to the bearing during operation of the crank mechanism.

Preferably, the floating bearing comprises an axis of rotation around which it can rotate, so that the lever can rotate as well. This axis of rotation is preferably perpendicular to the middle length axis of the lever.

This preferred or inventive embodiment of the present invention has the advantage that the length of the package and/or the sealing time can be adjusted without changing the upper dead center of the crank mechanism.

The motor that drives the crank is preferably an electromotor, more preferably a servo motor or a step motor. In case the floating bearing is moved relative to the frame, this is preferably also done by an electromotor, more preferably, a servo motor or a step motor.

In a preferred embodiment of the present invention, the movement of lever is restricted to a combination of rotational and a linear movement, even though the lever is mounted in a floating bearing. In this case, the floating bearing additionally has a rotational degree of freedom.

Another subject matter of the present invention is a method to continuously or semi continuously produce a package by applying a longitudinal seal with longitudinal sealing means and a cross-seal with cross sealing means to a tube made from a plane film and by cutting the package off the film by cutting means, wherein the cross sealing means and the cutting means are moved during sealing and cutting by a crank mechanism comprising a lever, wherein the length of a package and/or the sealing time of the cross sealing means is adjusted by altering the leverage of the lever.

The disclosure made regarding this subject matter of the present invention also applies to the other subject matters and vice versa. Subject matters disclosed regarding this subject matter can be combined with other subject matters and vice versa.

According to this embodiment of the present invention, the crank mechanism comprises a lever with an adjustable leverage, for example between the part of this lever that is connected to the rotating drive, for example a motor, of the crank mechanism and the part that is directly or indirectly connected to the sealing- and/or cutting means. Preferably the ratio between the length of the lever between the connection to the rotating drive and a bearing of the lever and the length between this bearing and the connection to the sealing- and/or cutting means is altered in order to change the sealing time and/or the length of the package. The adjustment is preferably done prior to the production of a series of packages. Since only the leverage has to be adjusted while the upper dead center remains unchanged, this can be done automatically, by for example punching the desired package length and/or the desired sealing time into the operation panel of the vertical flow wrapper as input parameters. The appropriate leverage to achieve the desired input parameters are then set automatically. It is even possible, that the leverage is adjusted by a control scheme, which measures the package length and/or the sealing time and/or the quality of the cross seal and then adjusts the leverage automatically.

The film is advanced preferably continuously and more preferably at a constant speed.

The sealing time is preferably increased or decreased without changing the advancement- speed of the film.

Preferably, the lever is mounted to the frame by a bearing, wherein the bearing is a floating bearing, which can be moved relative to the frame and/or to the lever to alter the leverage. Preferably, the lever rotates back and forth around this bearing during operation of the crank mechanism.

Preferably, the bearing is moved relative to a ramp in order to adjust the leverage.

Preferably, the crank mechanism comprises a motor, wherein the rotational position of the output of the motor is more preferably determined. This preferred embodiment of the present invention allows an exact control of the inventive method or the inventive flow wrapper because the exact position of the cross sealing-, cutting- and/or forming means is always known and/or the motion of these means can be controlled exactly.

In case the inventive flow wrapper or the inventive method comprises the utilization of a floating bearing, which is movable relative to the frame of the machine, preferably, the position of the bearing is determined, preferably for control purposes.

According to an inventive or a preferred embodiment of the inventive method, the upper dead center of the crank mechanism is maintained constant and only the lower dead center is altered in order to change the length of a package and/or the sealing time. The invention is now explained according to figures 1 - 6. These explanations do not limit the scope of protection. The explanations are applicable for all inventions of the present application, respectively.

Figure 1 shows the inventive flow wrapper.

Figures 2 and 3 show an embodiment of the crank mechanism.

Fig. 4 shows a package.

Figure 1 shows the inventive flow wrapper 1 with a frame 27. A film 3, for example a plastic film or a paper material is unrolled from a reel 2 and transported by means of a film feed 4 to a forming unit, which comprises a forming-shoulder 6 and a forming tube 5 which form the plane film 3 into a tube, whose edges are subsequently sealed together by a longitudinal seal. The tube is then filled with the packaging-item and provided with cross seals by a cross sealing means 7. These packages, for example pouches or doy style bags, are then cut apart by a cutting means 7. In case that the package shall have gussets, forming means are also needed, which are, in general, also connected to the drive of the cross sealing- and cutting-means. The flow wrapper according to the present invention operates continuously or semi continuously, i.e. the film moves continuously or intermittently. The movement of the film tube can be utilized with drive means, which are, in most cases, provided next to the tube up stream from the means 7 and/or the means 7, particularly the sealing means can be used to pull the film tube down. Consequently, the cross sealing means 7, the cutting means and/or the forming means 7 have to be moved at least when they are in contact with the moving tube. This is utilized by a crank mechanism 23 which reciprocates the means 7 between an upper dead center 8 and a lower dead center 9. The distance between the upper and the lower dead center determines the length X of the package and/or the sealing time.

An embodiment of this crank mechanism 23 is shown in Figures 2 and 3. A rotating motor 14 with a crank, for example an electro motor, particularly a servo motor or a step motor, which sends a signal to a control unit about the current position of the crank of the motor, is connected via a pivot bearing 1 1 with the first end of a first lever 15 and moves the first lever, particularly its second end, up and down, which is connected via another pivot bearing 1 1 to a first end of the second lever 16. This second lever 16 is mounted directly or indirectly to the frame 27 of the inventive flow wrapper 1 by means of a floating bearing 12, i.e. the lever 16 can move relative to the floating bearing 12 and/or the floating bearing 12 can be moved relative to the second lever 16. The relative movement can take place during the adjustment of the lower dead center and/or during operation of the crank mechanism. The floating bearing 12 can move relative to the frame 27 of the flow wrapper and relative to the second lever 16. The floating bearing 12 is preferably provided on a ramp 13 which is fixed directly or indirectly to the frame 27 of the flow wrapper. This ramp 13 can be provided at an angle a relative to a horizontal plane wherein a is preferably larger than 0° and more preferably smaller than 90°. Preferably, a is fixed. The floating bearing 12 can be moved relative to the lever 16 and/or to the frame 27 here the ramp 13 in order to adjust the leverage of the lever 16, i.e. the ratio between the length L1 and the length L2 by which a bearing 21 extends away from the bearing 12, wherein in the present case, L1 remains always constant while L2 is changed. The movement of the floating bearing is depicted by the double-arrow 18. By adjusting the ratio L1/L2, the position of the lower dead center 9 is altered. The floating bearing 12 also comprises a pivot bearing 1 1 , so that the lever 16 can pivot around the bearing 12 particularly during operation of the crank mechanism. A third lever 17 is connected to the lever 16 at a fixed distance L1 away from the first end by means of a pivot bearing 21. The first end of the second lever 16 is also connected with a pivot to the first end of a fourth lever 22, whose second end is connected to a fixed bearing 20 via a pivot bearing. Hence, this lever 22 can only rotate around the pivot bearing 1 1 of bearing 20 and

consequently, the first end of the second lever 16 can only move on a circle. The pivot bearing that connects levers 15, 16 and 22 can be one and the same. The second end or the third lever 17 is mounted via pivot bearing 1 1 to a floating bearing 28, which moves along a plane 10 fixed to the frame of the flow wrapper, which is in the present case provided vertically. The second end of lever 17 and/or the bearing 28 are also directly or indirectly connected to the means 7. Due to the motion of the crank mechanism 23, the means 7 are reciprocated between the upper- and the lower dead center 8, 9 as depicted by double arrow 19. Preferably, regardless of the ratio L1/L2, the distance D between the upper dead center 8 and the lower end of the forming tube 5 remains always constant, regardless of the ratio L1/L2. Only the position of the lower dead center 9 and hence the distance between the upper- and the lower dead center 9 is altered by changing the ration L1/L2. This is particularly advantageous for example for packages which are not only sealed and cut but which are further formed by forming means, for example provided with one or more gussets, and wherein the forming means cooperate with the lower end of the forming tube.

The distance between the upper- and the lower dead center is altered by moving the bearing 12 and thus changing the leverage L1/L2, wherein in the present case, L1 remains always constant even though L2 is changed. The bearing 12 is preferably moved along the ramp 13 by a rotating spindle, which is preferably driven by a servo motor or a motor with position control. A comparison between Figures 2 and 3 shows that in the example according to Figure 3, the distance L2 has been increased in comparison to according to Figure 4. This leads to a reduced distance between the upper- and the lower dead center. The position of the upper dead center and/or the distance D between the lower end of the forming tube and the upper dead center 8 remains, however, always the same.

Figure 4 shows an example of a package which can be produced with the inventive vertical flow wrapper. The package 26 is made from a plastic film whose ends are sealed together by the longitudinal seal 25. The top and the bottom of the package are closed by a cross seal 24, respectively. The length X of the package can be altered by moving the lower dead center 9 away or towards the upper dead center 8 parallel to the motion of the film tube. The same is true for the sealing time.

List of reference signs:

1 Vertical Flow-wrapper

2 Reel

3 Film, plastic film, paper

4 Film-feed

5 Forming-tube

6 Forming shoulder

7 Cross sealing means, cutting means and/or forming means

8 Upper dead center

9 Lower dead center

10 Guiding means

1 1 Pivot bearing

12 Floating bearing

13 Ramp

14 Rotating motor

15 First lever

16 Second lever

17 Third lever

18 Movement of the floating bearing 12

19 Movement of the cross sealing means 7, cutting means 8 and/or forming means

20 Fixed bearing

21 Connection between the first lever 15 and the fourth lever 22

22 Fourth lever

23 Crank mechanism

24 Cross seal

25 Longitudinal seal

26 Package

27 Machine frame

28 Floating bearing

29 Motion of the film tube

L1 length

L2 length

D distance between lower end of the tube and upper dead center

a angel of inclination >0° < 90°

X length of the packaging