MACHINE FOR PACKAGING MATERIAL IN A LONGITUDINALLY AND TRANSVERSALLY SEALED TUBE

Abstract: The present invention relates to a packaging machine for packaging pourable food products which comprises means for longitudinally sealing a web of continuous packaging material to form a tube, a number of pairwise cooperating sealing jaws for clamping and sealing the product filled tube at regularly spaced intervals, and position controlling means. The position controlling means (400, 420; 20) comprises means for automatically adjusting the length of the path of the packaging material web before transversal clamping and sealing such that the position of serving means provided on the material web can be controlled to have a predetermined position on finished, sealed packages. The invention also relates to a method of position controlling in a packaging machine for packaging pourable food products.

Description: Title : MACHINE FOR PACKAGING MATERIAL IN A LONGITUDINALLY AND TRANSVERSALLY SEALED TUBE FIELD OF THE INVENTION The present invention relates to a packaging machine for packaging pourable food products and which comprises means for longitudinally sealing a web of continuous packaging material to form a tube. A number of pairwise cooperating sealing jaws are provided which operate in a reciprocating manner for clamping and sealing there between the product filled tube at regularly spaced intervals. Position controlling means are provided to ensure that serving means provided on the web are positioned correctly on finished, sealed packages. Serving means are here taken to mean designs, perforations, straw holes etc. The invention also relates to a method of position controlling in a packaging machine for packaging pourable food products of the above mentioned kind including the steps of; feeding a continuous web of packaging material; forming the web into a tube; sealing the tube longitudinally; filling the tube with a pourable food product; detecting equidistantly provided markings or similar on the web. The invention still further relates to an arrangement for position controlling in a packaging machine. Particularly the invention relates to design correction. STATE OF THE ART It is well known to produce packages for liquid or pourable food products from a roll of packaging material which comprise layers of fibrous material, such as paper, which is covered on both sides with a thermo-plastic material e . g.. polyethylene . The side of the packaging material that may be in contact with the food product in the package also comprises a layer of barrier material, e.g. an aluminium foil which is coated with a thermoplastic material. To produce packages of the above mentioned kind, packaging machines are fed from a roll of packaging material in web form as referred to above. The packaging material is sterilized preferably in the packaging machine through the application of a chemical sterilization agent, for example a hydrogen peroxide solution. During the sterilization step the sterilization agent is also finally removed from the surfaces of the packaging material, e.g. through heat vapourisation. The sterilized packaging material is then formed into a tube which is longitudinally sealed. The tube is filled with a sterilized pourable food product. Examples on such pourable food product are for example fruit juice, pasteurized or ultra-high temperature treated (UHT) milk, wine, tomato sauce, vanilla sauce or high viscosity products in general etc. The filled tube subsequently passes between (a) pair(s) of endless chains or reciprocating members carrying sealing means, particularly heat sealing jaws on one chain of a pair and counter sealing jaws on the other chain, wherein the sealing means clamp and seal the tube at regularly spaced intervals. The resulting sealed packaging materials bands are then cut between consecutive filled and sealed packages thus giving a number of separate packages. Different kinds of packages are known, e.g. parallelpiped packages. Such are known as for example Tetra Brik™. Another known package is the so called Tetra Pris a™ which is a parallelpiped package with bevelled surfaces. To produce such packages two endless chain conveyers are provided which are provided with a number of sealing jaws and counter sealing jaws respectively. The two endless chains define respective endless paths which face each other and are parallel to each other and between which the tube of packaging material is fed. The (heat sealing) jaws on one endless chain cooperate with corresponding counter pressure sealing jaws on the other endless chain in a reciprocating movement to clamp the tube at regular distances and to seal it such that transversal seals are provided and pillow-shaped packages are resulting which then may be formed into the final shape, e.g. through folding, which however not is relevant for the present invention. Tetrahedrally shaped packages as for example Tetra Classic™ or Tetra Classic Aseptic™ are also known. Then there are two pairs of endless chain conveyers. Each pair consists of one endless chain carrying (heat) sealing jaws and another carrying counter sealing jaws so that upon the clamping and sealing operation, which is carried out alternatingly by the jaws on the respective pairs such that a first sealed band of material extending in a first direction is followed by a subsequent sealed band of material extending in a direction perpendicular to it etc. in an alternating manner. In that way tetrahedrally shaped packages are produced. Often the packaging material is pre-printed on one side with a succession of identical, equally spaced design patterns which are to be located on the portions that eventually will form the outer surfaces of the packages. The packaging material web may also be provided with for examples straw holes, perforations or perforated corners etc. In this application the designs, straw holes, perforations etc. are all denoted serving means in that they in one way or another serve the user or the manufacturer. Common for these serving means is that their location on a finished package should not vary from one packages to another, i.e. in other words the packaging material web has to be positioned correctly to ensure that the printed design and/or straw hole and/or opening device such as a perforated corner portion be positioned correctly on a finished package. It is however difficult to ensure that the tube of packaging material be fed such that the packages are formed, sealed and finally cut in such a way that the designs etc. are correctly located. The packaging material may be deformed during operation since it is subjected to mechanical deformation, heat, the formed tube is filled by a product etc. Variations may also be produced during the preprinting operation (or during forming of perforations etc) . Known example on packaging machines as referred to above are the packaging machines known as TBA/19 and TBA/21, available from Tetra Brik Packaging Systems, Via Delfini 1, Modena, Italy, for manufacturing parallelpiped packages known registered trademark Tetra Brik™ or parallelpiped packages with bevelled corners known by the registered trademark Tetra Prisma™. In these known machines automatic design correction systems are used having folding flaps connected to the sealing jaws of the machine in order to pull more or less material into the forming and sealing members of the packaging machine during operation. Such arrangements are described in EP-A-887 265 and IT Patent 1 296 062 granted on June 9, 1999. These solutions are however quite complicated. Moreover if the concepts were to be implemented for the production of tetrahedrally shaped packages, they would be even more complicated. It is also known to use a so called folding ruler above each sealing jaw of the packaging machine in order to adjust the length of the path of packaging material web so as to ensure that the printed design is positioned correctly on the finished package. This is e.g. known from the production of tetrahedrally shaped packages. However, to use such folding rulers is disadvantageous in that, if during a production run, the packaging material web is found not to be positioned correctly with the respect to the finished package, production actually has to be stopped and the folding rulers have to be replaced with shorter or longer folding rulers in order to provide for the needed design correction before production can be restarted. Thus, in other words the folding rulers have to be exchanged manually, and a number of different kinds of folding rulers need to be available, the operator needs to know which folding ruler to use etc., which is disadvantageous. This is both laborius and time consuming and moreover, if a production run is to be stopped, when starting up again, other problems may be introduced. Generally problems are produced at the start up phase of a machine since the operation of the sealing jaws have to be synchronized to the material web. For high speed operation packaging machines even a very small shift in a set theoretical location of designs may, if not corrected in real time, eventually increase to the point that packages have to be disposed of. For preformed perforations straw holes etc. pulling operations by e.g. folding flaps etc. and braking means needed to brake the web may be critical since a perforation may tear or be weakened, just as well as a straw hole, which is serious in that, then, not only the optics of the package is affected, but also its functionality. Thus, none of the suggested solutions works satisfactorily. Known machines for producing Tetra Classic™/Tetra Classic Aseptic™ are TC/TCA 65 available from TetraPak Stalvall, Sweden. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a packaging machine as initially referred to through which position control is provided for such that serving means such as designs, straw holes or perforations are positioned correctly on finished packages. Particularly it is an object of the invention to provide a packaging machine through which position control, particularly design correction, can be done in a quick and precise manner and through which the position control can be performed in a continuous manner without requiring stops in the production run when deviations in position etc. are detected. It is also an object of the invention to provide a packaging machine which does not require operator invention. Still further it is an object to provide a. packaging machine as referred to above through which position control or design correction is enabled in an easy and uncomplicated manner. Particularly a packaging machine as initially referred to is needed which operates at a high speed and still assures that serving means, e.g. designs, straw holes etc. are positioned correctly on finished packages. Still further an arrangement providing for position control, particularly design correction, in a packaging machine as initially referred to is needed through which the above mentioned objects can be met. Particularly an arrangement is needed which can be easily installed on existing packaging machines. Particularly a machine and an arrangement respectively as referred to above is needed which allows correction in real time and through which even minor shifts in the theoretical location of serving means, e.g. designs etc. as referred to above, can be handled at an early stage. A machine and an arrangement is also needed through which can be avoided that produced packages need to be disposed of because of incorrect location of designs, or other serving means. More generally it is an object of the invention to provide a packaging machine and an arrangement respectively for continuously producing a septic sealed packages containing pourable food products through which the drawbacks typically associated with the known machines can be obviated as far as position control or design correction is concerned. Further yet it is an object to provide a packaging machine and an arrangement for use with a packaging machine respectively wherein position control/design correction can be achieved without producing a mechanical load on the web that might give rise to damages on e.g. perforations, straw holes etc. Still further a method of position controlling in a packaging machine as initially referred to is needed through which the above mentioned objects are met. Therefore a packaging machine as initially referred to is provided wherein the position controlling means comprises means for automatically and continuously adjusting the length of the path of the packaging material web before clamping and sealing such that the position of serving means provided on the package material web can be controlled to have a predetermined position on finished, sealed packages. As referred to above the serving means may comprise designs, but also straw holes, perforations or similar. Particularly the position controlling means are arranged to act up-streams of the respective sealing jaws. The position controlling means comprises folding rulers and actuating means operable to adjust the length of the folding rulers. One of the sealing jaws of each pair of sealing jaws, particularly the counter sealing jaw, comprises a folding ruler which is slidably mounted in the sealing jaw. The folding ruler comprises a ruler part for acting on the material web and a rear part on which is actuated to slidably move the folding ruler with respect to the sealing jaw in which it is mounted. Advantageously retaining means are connected to the folding ruler in the sealing jaw which retaining means particularly consists of a spring biased towards the folding ruler and which on the opposite side carries a rotatable ball bearing. The actuating means may comprise a pivotably mounted cam element actuating on the ball bearing and a driving means controlling the cam element in response to a signal from control means communicating with detecting means, e.g. a photocell for detecting the position/deviation in position of markings (or serving means) provided on the package material web. In one embodiment the driving means comprises a multistep air cylinder arrangement driving a link system connected to the cam element. The air cylinder arrangement may comprise three air cylinders connected in series with cylinder strokes of 2 mm, 1 mm and 0,5 mm respectively such that the folding ruler can be controlled to take any of seven different positions with respect to the sealing jaw in which it is mounted. In an alternative embodiment the driving means comprises a stepping motor. The package material web can be provided with equidistantly spaced markings or index marks to be used by the detecting means for detecting the position of the markings, which detecting means are connected to a control unit controlling the actuating means. Instead of separately provided markings to be used exclusively for detection purposes, serving means may also be used for detection purposes, such as for example straw holes etc. In a particular embodiment the sealing jaws are arranged on endless chains such that, in operation, consecutive seals are provided which form an angle of substantially 90° with respect to each other such that tetrahedrally shaped packages are produced, c.f. for example Tetra Classic™ or Tetra Classic Aseptic™ as referred to earlier in the application. Therefore also an arrangement for controlling the position of serving means on a continuous packaging material web, for use in a packaging machine for packaging pourable food products as referred to above, is provided, which comprises position controlling means for automatically adjusting the length of the path of the package material web before clamping and sealing in the packaging machine such that the position of serving means provided on the material web can be controlled to have a predetermined position on finished, sealed packages. The position controlling means particularly comprises actuating means operable to adjust the length of folding rulers provided in association with sealing jaws provided on an endless chain for cooperation with sealing jaws provided on another endless chain. Particularly the actuating means comprises a pivotably mounted cam element actuating on a ball bearing connected to the folding ruler via retaining means, and driving means controlling the cam element. The driving means particularly comprises a multistep air cylinder arrangement driving a link system connected to the cam element. The link system may be optionally provided, e.g. if the driving means are located on the outside of the machine housings. Alternatively the driving means comprises a stepping motor. The position controlling means further comprises detecting means for detecting the position of markings or serving means provided on the continuous material web introduced into the packaging machine which detecting means are connected to a control unit controlling the actuating means and providing a signal to said control unit when a deviation in position is detected such that the control unit controls the actuating means to adapt the length of the folding ruler. Alternatively signals are provided to the control unit upon detecting a marking or similar such that the control unit interprets and evaluates the signal to determine whether a position correction has to be done or not, or if the position of the folding ruler needs to be changed in relation to its current position. Particularly the arrangement is used in a packaging machine for producing tetrahedrally shaped packages. Therefore also a method of position controlling in a packaging machine for packaging pourable food products as referred to earlier in the application is provided. The method is characterized through steps of; detecting the position of markings or similar; providing signals indicative of the position/deviation to control units; automatically adjusting the distance the web travels before performing a transversal clamping/sealing operation on the tubeshaped package material web. In a preferred embodiment the method further comprises the steps of; activating actuation means acting on a folding ruler displacably mounted with respect to a sealing jaw to increase/reduce its length thus adjusting the path length of the material web before clamping/sealing transversally. Still further one sealing jaw in each pair comprises a folding ruler which is slidably mounted therein to act on the material web. Even more particularly the method includes the steps of; acting on a ball bearing connected to the folding ruler, which ball bearing is in contact with a cam element of the actuating means. Further yet the serving means may comprise design patterns, straw holes, perforations or similar. Advantageously the method includes the steps of; driving the actuating means using a stepping motor, an air cylinder arrangement or similar. In an advantage of the present invention that a continuous and automatic control of for example the position of designs is enabled and particularly that an automatic and continuos design correction is enabled. It is also an advantage of the invention that an arrangement is provided which can be built into already existing machines as well as the concept can be used for when building the new packaging machines. BRIEF DESCRIPTION OF THE DRAWINGS The invention will in the following be further described in a non- limiting manner and with reference to the accompanying drawings, in which: FIG. 1A very schematically illustrates a packaging machine with position controlling means, FIG. IB in an enlarged view schematically showing the stepping motor of Fig. 1A, FIG. 1C an enlarged view showing the detecting means of Fig. 1A, FIG. 2 schematically illustrates a cross-sectional view of a counter pressure sealing jaw with a folding ruler mounted therein, FIG. 3 illustrates a pair of cooperating sealing jaws of which one includes a folding ruler, FIG. 4A is a detailed view of a counter pressure sealing jaw with a folding ruler, retaining means and a ball bearing, FIG. 4B is an exploded view of the means of FIG. 4A, FIG. 5 shows the actuating means including driving means and a cam element according to a first embodiment, FIG. 6 shows the actuating means including driving means and a cam element according to a second embodiment, FIG. 7A illustrates the actuating means acting on the folding ruler and making it assume a first position with respect to the sealing jaw, FIG. 7B illustrates the actuating means acting on the folding ruler making it assume a second position with respect to the sealing jaw, and FIG. 8 very schematically illustrates a part of packaging machine with a multistep air cylinder as driving arrangement . DETAILED DESCRIPTION OF THE INVENTION Fig. 1 very schematically illustrates a packaging machine 100 for producing tetrahedrally shaped packages such as Tetra Classic™ or Tetra Classic Aseptic™. A preprinted material web 101 is provided on a roll from which it is fed to sterilizing means 102 in which the material web is exposed to e.g. hydrogen peroxide. Then it is fed on to heating means 103 for removing the sterilization agent, e.g. through heat vaporisation. The material web 101 passes breaking rollers 104,104 and is subsequently formed into a tubular shape which is longitudinally sealed. Preprinted, markings (or serving means) are then detected by detecting means e.g. in the form of a photocell 105 for registering markings printed on the packaging material web. Alternatively there may be more than one photocell. The markings may also be of different kinds, index markings, bar codes, but they may also consist in the serving means themselves which then serve dual purposes, namely as indications (markings) and their actual purpose, e.g. a straw hole a perforation or similar. They may, according to different implementations be arranged inside or outside the tube. Moreover it is possible to perform the detection step before the web is formed into a tube. In one embodiment the photocell 105 reads markings which are equidistantly provided on the material web 101. The information obtained by the photocell 105 is transmitted over cable 106 to control unit 107 which is arranged in association with the machine or externally of the machine. In the control unit 107 the information is processed and a decision is made as to whether the position needs to be corrected or not, and, as to how it is to be corrected. The control unit 107 is programmable and may e.g. calculate the position of the marking (and thus the position of the serving means with respect to a reference position corresponding is a desired position on a finished package. The control unit 107 controls the driving means 410 which in this embodiment comprises a stepping motor which is shown somewhat more in detail in Fig. IB, of indication IB of Fig. 1A. The position of the photocell 105 is somewhat more clearly illustrated in the enlarged view 1C of Fig. 1C. The driving means forms part of actuating means (not shown in Fig. 1A) acting on a folding rulers provided in association with the sealing jaws used for transversal clamping and sealing of the tube, which is filled by a product, at regular intervals. The functioning will be more thoroughly explained in the following. Fig. 2 is a schematical, cross-sectional side view of a counter (pressure) sealing jaw 1 with a folding ruler 5. The counter sealing jaw 1 comprises a main body 2 to which first and second volume defining portions 3,3 are connected via fastening means 4. A contact surface 6 contacts the web during the clamping and sealing step. The main body 2 is provided with attaching means 7 for connection to an endless chain (not shown) which drives a number of similar sealing jaws in a synchronous motion along the tubular material web (see Fig. 3) substantially in accordance with prior art machines. The attaching means 7 forms a pivot point for the sealing jaw with respect to the endless chain. A small guide roller 9 is located at the opposite end of the sealing jaw. A large guiding ruler 8 is arranged on the main body 2 for providing support of the sealing jaw during the final sealing phase. In this figure merely a folding ruler 5 is illustrated and it is not indicated how, according to the inventive concept, this folding ruler is slidably or displacably arranged which will be further described with reference to for example figures 4A, 4B. Fig. 3 is a schematical illustration of counter sealing jaw 1 of Fig. 2 as cooperating with a heat sealing jaw 1' to clamp and heat seal the tubular web 101 provided therebetween. As in state of the art machines the sealing jaws 1, 1' are driven in a reciprocating manner to, at regular intervals, clamp and seal the web between them such that transversal seals are provided. Each of the sealing jaws 1, 1' are connected to an endless chain (not shown) each of which chains comprise a plurality of sealing jaws respectively for mutual cooperation as described above. For the production of tetrahedrally shaped packages another pair of such chains is provided perpendicularly to the aforementioned chains and cooperating jaws on the two pairs of endless chains act alternatingly such that consecutive, transversal seals will be provided perpendicularly in relation to each other. This is known from packaging machines for producing e.g. Tetra Classic™ or Tetra Classic Aseptic™. Figs. 2 and 3 are merely illustrated to explain the functioning of sealing jaws wherein each counter pressure sealing jaw is provided with a folding ruler able to influence the path of travel of the material web 101. Fig. 2 in principle is a cross-sectional view along the lines I-I of Fig. 3 and arrows C,C indicate the direction of movement of the sealing jaws for performing the clamping and sealing operation. Fig. 4A illustrates a counter pressure sealing jaw 10 with a displacably or slidably mounted folding ruler 20 arranged between a first portion 11 and a second portion 12 serving as a bearing cover. The first and second portions 11,12 are held together by bushings 18,18. A ball bearing 26 is connected to the folding ruler 20 so as to transmit a movement of a cam element of actuating means which are not shown in this figure. This will be further explained with reference to Figs. 5, 6, 7A, 7B. The exploded view of Fig. 4B showing the counter pressure sealing jaw of Fig. 4A discloses in a more detailed manner how the ball bearing 26 actually is connected to the folding ruler 20 having a ruler part 21 for acting on the material web (not illustrated herein) and a rear part 22 on which is actuated to produce the sliding movement of the folding ruler 20 with respect to the sealing jaw 11,12 in which it is mounted. Bearing rollers 16,16 are mounted on a shaft 15 and connected thereto by retaining rings 17,17. Between the first and the second sealing jaw portions 11,12 a plain bearing 13 is provided and a plate 29 is fastened by screws to the first portion 11 for assembling purposes. The ball bearing 26 is mounted in retaining means or rod 25 by a pin crossing two holes at a fork shaped end portion of the retaining means or rod 25 between which it is held by washers 27,27. The opposite end of the retaining means 25 comprises a notch in which a protruding portion of the rear part 22 of the folding ruler 20 is introduced such that the retaining means 25 are active in displacing the folding ruler 20 in the direction of the movement produced on the ball bearing 26 by the actuating means (not shown herein) . Mounted on the retaining part of rod 25 is a spring 23 urging the folding ruler outwards. The spring 23 is mounted on the part of the retaining means or rod 25 facing the folding ruler 20 via a bearing member 10. Thus, when the actuating means, via the cam element exerts a pressure on the ball bearing 26 rolling on the cam element (not shown) , this force will be transferred via the retaining means 25, and urge the folding ruler 20 outwards with respect to the sealing jaw in which it is mounted and act on the material web so as to prolong the path the material web travels before it actually is clamped and heat sealed between the counter sealing jaw 10 and a cooperating heat sealing jaw (not shown) . In Fig. 5 actuation means 40 is illustrated in which the driving means 41 comprisies a multistep air cylinder arrangement controlled by the programmable control unit (not shown in this figure) for activating a cinematic transmission procedure to change the position of the cam element 60 which determines the movement of the ball bearing 26 (not shown) as illustrated in Fig. 4A, 4B; c.f. also Figs. 7A, 7B below. The multistep cylinder arrangement may for example comprise a three step cylinder arrangement with three air cylinders arranged in series which have stroke length of 2 mm, 1 mm and 0,5 mm respectively, resulting in seven different positions corresponding to a displacement of 0,5 mm, 1 mm, 3,5 mm respectively. The fourth step may for example be taken to represent the basic setting case the path of the web need not to be changed i.e. no measure is taken to correct the position. Of course this merely relates to one particular implementation and any kind of multistep cylinder arrangement may be used. The invention is of course not limited to the use of multistep cylinder arrangements as driving means but this merely relates to one particular implementation. However, in this embodiment the multistep cylinder arrangement 41 is connected to a rod 42 which forms part of the link system 65 responsible for the mechanical transmission to change the position of the cam element 60. Rod 42 is connected to a lever 43 in that its end portion distant from the air cylinder arrangement 41 is introduced into a fork shaped portion of the lever 43. The lever 43 comprises a through hole which is vertically provided substantially at the center of the lever and it is connected to a bracket 51 via a protruding forked portion 54 which is vertically arranged and contains through holes to be arranged such that the through hole of the lever fits to the through holes of the fork shaped portion 54 through which holes a pin is inserted and fixed via a retaining ring and bushings 49. At the end portion of the lever 43 which is opposite to the portion at which the rod 42 is inserted, another through hole is provided to, via a screw 44 fixed by a nut 45, fasten an end portion of a compression rod 46. The compression rod 46 is spring biased by a spring 47 and a washer is inserted into the bracket 51 having a through hole arranged substantially at its midpoint and on the other side of which the other end portion of the compression rod 46 is connected to a forked link 56 which by a pin or similar is pivotably connected to the cam element 60. The cam element 60 substantially at its middle portion is provided with a hole for taking up the connecting pin 57 via the forked link 56. At the upper portion of the cam element 60 another through hole is provided on which another forked link 58 is arranged and fixed by a pin 59. This upper forked link is fixed to the housing of the machine and the cam element can be pivoted around the pivot point, formed by pin 59. At the opposite, free end point of the cam element sliders 63,63 are arranged on either side thereof and fastened to it by screws 6 . The movement transferred by the driving means 41 is transferred via the compression rod 46 connected to the cam element 60 via the forked link 56. The maximum response to a transferred movement from a driving means 41, thus is provided at the lower, free position of the cam element 60. The ball bearing 26 (not shown on this figure) , rolls along the cam element 60 which will be more clearly illustrated through Figs. 7A, 7B. If the cam element is urged towards the ball bearing, the action is via retaining means transferred to the folding ruler which then prolongs the path the material web has to travel. Fig. 6 shows an alternative embodiment of an actuating means 401 comprising a stepping motor. Fig. 6 is a figure similar to that of Fig. 5 showing actuating means 400 including a stepping motor 410 as a driving means instead of the multistep air cylinder arrangement 41 of Fig. 5. The stepping motor 410 is via a ball bearing (not shown) connected to an eccentric 412 which over a retaining ring (not shown) is connected to a proximity switch (not shown) in a conventional manner through a bracket 411. The eccentric and the proximity switch are connected to a securing means, e.g. here a ball joint eye 414, by a screw 413. A pin 415 is fastened to the ball joint eye 414 at one of the end portion and the other end portion of the pin 415 is connected a forked link 416 which by a pin 417 is connected to the cam element 420 which is similar to cam element 60 of Fig. 5. The upper part of the cam element is provided with a through hole for the connection of another forked link 418 via a pin 419. The cam element 420 is pivotably mounted via said fork link and fastening mean 422 to the machine housing such that the ball bearings associated with the sealing jaws on the endless chain contact the cam element 420 as discussed above. In Figs. 7A and 7B respectively will be illustrated how the cam element acts on the ball bearing of a sealing jaw. It is shown how the actuating means 400 as shown in Fig. 6 including a stepping motor 410 actuates upon cam element 420 through a rod 415. The cam element 420 is fixedly attached to a fixed part of the machine housing by means 418 and it can be pivoted around pin or screw 419 forming a pivot point. In Fig. 7A the folding ruler 420 is supposed to be drawn in as much as possible and then there is no pressure exerted on the roller bearing 26 by the cam element 420- The path of the web is then shortened as compared to a basic setting. Fig. 7B illustrates a situation in which the web (not shown) is forced to take a longer path since the folding ruler 20 is urged outwards. The cam element 420 is pivoted counterolockwise around the pivot point since the stepping motor 410 via rod 415 forces to the right in the Figure thus urging the spring biased roller bearing 26 inwards relative to the sealing jaw 10. The roller bearing 26 which, as more thoroughly described with reference to Fig. 4A, 4B, against the action of a spring (not shown herein) is urged towards the folding ruler 20 which then is pressed outwards, in other words the folding ruler can be said to become longer. Of course any driving means can be used, not only a stepping motor or a multistep air cylinder arrangement but also e.g. hydraulical means can be used. The cam element can be also be substituted by other similar elements as long as a driving means in one way or another acts upon means, preferably a ball bearing, connected to a displaceably mounted folding ruler so as to displace it with reference to the sealing jaw. Finally, Fig. 8 very schematically illustrates a part of machine housing 110, to the outside of which a multistep air cylinder arrangement 41 in Fig. 5 is fixed. The link system connecting to the cam element 60 is not shown in this figure since it passes through the bracket or machine housing but the forked link 56 connected to the cam element 60 is shown and it can also be seen how the forked link 58 is fixedly attached to the housing such that the cam element can pivot around the point of attachment to the forked link 58. In the figure only one counter sealing jaw 10 is illustrated but it can be seen how the roller bearing 26 connected to the sealing jaw moves along the cam element 60 such that the position of the active length of, the folding ruler 20 can be controlled. As referred to earlier in the application a number of sealing jaws 10 are mounted on an endless chain for cooperation with a number of sealing jaws provided on another chain to clamp a material web there between. If tetrahedrally packages are to be provided, there are two more endless chains carrying counter pressing sealing jaws on one and heat sealing jaws on the other respectively. Then a further cam element needs to be connected to other driving means to enable position control also for the clamping and sealing operation to take place in a perpendicular direction as discussed in the foregoing. For reasons of clarity only one part of the fixed housing is illustrated but actually there should be four similar parts, of which two carry driving means, for driving each a cam element If a folding ruler is prolonged, this means that just before clamping and sealing the material web has to travel a longer distance, and when the clamping action is activated, it should also be maintained until the subsequent pair of cooperating sealing jaws, which e.g. act in a perpendicular direction, actually clamp (and seal) the web. Thus, a continuous and automatical control of the position as for as serving means are connected is obtained and the path of the package material web is adjusted continuously through controlling the length of the folding rulers. The invention is of course not limited to the particularly illustrated embodiments but it can be varied in a number of ways within the scope of the appended claims. Particularly any kind of a appropriate driving means may be used as well as any appropriate kind of detecting means. Moreover, how the detection is performed can be provided for in different manners. Markings can be provided for the purposes of being detected only or for the purpose o.f position controlling only, or alternatively already existing serving means that anyhow should have been provided, can be used etc. The inventive concept is also applicable to production of different kinds of packages such as brick shaped packages, tetrahedrally shaped packages etc.

Claims: CLAIMS 1. A packaging machine (100) for packaging pourable food products, comprising means for longitudinally sealing a web (101) of continuous packaging material to form a tube, a number of pairwise cooperating sealing jaws (1,1' ;10) for clamping and sealing the product filled tube at regularly spaced intervals, and position controlling means ( 40, 20 ; 400, 20) , c h a r a c t e r i z e d i n that the position controlling means (40, 20; 400, 20) comprises means for automatically adjusting the length of the path of the packaging material web (101) before transversal clamping and sealing such that the position of serving means provided on the material web can be controlled to have a predetermined position on finished, sealed packages. 2. A machine according to claim 1, c h a r a c t e r i z e d i n that the position controlling means (40, 20 ; 00 , 20 ) are arranged to act upstreams of the respective sealing jaws (1,1'; 10). 3. A machine according to claim 1 or 2, c h a r a c t e r i z e d i n that the position controlling means comprises folding rulers (20) and actuating means (40; 400) operable to adjust the length of the folding rulers (20) . 4. A machine according to claim 3, c h a r a c t e r i z e d i n that one of the sealing jaws (1;10) in each pair of sealing jaws comprises a folding ruler (5;20) which is slidably mounted with respect to said sealing jaw. 5. A machine according to claim 4, c h a r a c t e r i z e d i n that the folding ruler (20) comprises a ruler part (21) for acting on the material web (101) and a rear part (22) on which is actuated to slidably move the folding ruler (20) with respect to the sealing jaw (10) in which it is mounted. 6. A machine according to claim 5, c h a r a c t e r i z e d i n that retaining means (25) are connected to the folding ruler (20) associated with the sealing jaw (10) . 7. A machine according to claim 6, c h a r a c t e r i z e d i n that the retaining means (25) are spring (23) biased towards the folding ruler and on the opposite end carries a rotable ball bearing (26) . 8. A machine according to claim 7, c h a r a c t e r i z e d i n that the actuating means comprises a pivotably mounted cam element (60;420) actuating on the ball bearing (26) and a driving means (41;410) controlling the cam element (60;420). 9. A machine according to claim 8, c h a r a c t e r i z e d i n that the driving means comprises an air cylinder arrangement (41) driving a link system (65) connected to the cam element. 10. A machine according to claim 9, c h a r a c t e r i z e d i n that the air cylinder arrangement (41) comprises three air cylinders connected in series with cylinder strokes of 2 mm, 1 mm and 0,5 mm respectively such that the folding ruler (20) can be controlled to take any of seven different positions with respect to the sealing jaw (10) in which it is mounted. 11. A machine according to claim 8, c h a r a c t e r i z e d i n that the driving means comprises a stepping motor (410). 12. A machine according to any one of the preceding claims, c h a r a c t e r i z e d i n that the web (101) is provided with equidistantly spaced markings . 13. An arrangement according to any one of the preceding claims, c h a r a c t e r i z e d i n that the position controlling means further comprises detecting means (105) for detecting the position of the markings or serving means and in that said detecting means (105) is connected to a control unit (107) controlling the actuating means. 14. An arrangement according to any one of the preceding claims, c h a r a c t e r i z e d i n that the serving means comprises design patterns and in that the position controlling means comprises design correction means. 15. An arrangement according to any one of the preceding claims, c h a r a c t e r i z e d i n that the serving means are straw holes, perforations, e.g. perforated corners etc. 16. A arrangement according to any one of the preceding claims, c h a r a c t e r i z e d i n that the sealing jaws are arranged on endless chains such that: in operation consecutive seals are provided which form an angle of substantially 90° with respect to each other such that tetrahedrally shaped packages are produced. 17. A method of position controlling in a packaging machine for packaging pourable food products including the steps of: feeding a continuous web of packaging material, forming the web into a tube, - sealing the tube longitudinally, filling the tube with a pourable food product, detecting equidistantly provided markings or serving means on the web, c h a r a c t e r i z e d i n that it further comprises the steps of: when establishing deviations in position of the markings in relation to predetermined positions, determining in a control unit, based on the detection of markings/serving means if and/or how the path the web travels needs to be adjusted, automatically adjusting the distance the web travels before performing a transversal clamping/sealing operation to form a separate package. 18. The method of claim 17, c h a r a c t e r i z e d i n that it further comprises the steps of: activating actuation means acting on a folding ruler displacably mounted with respect to a sealing jaw to increase/reduce its length thus adjusting the path length of the material web before clamping/sealing transversally. 19. The method of claim 18, c h a r a c t e r i z e d i n that one sealing jaw in each pair comprises a folding ruler which is slidably mounted therein to act on the material web. 20. The method of claim 18 or 19, c h a r a c t e r i z e d i n that it includes the step of: driving the actuating means using a stepping motor, an air cylinder arrangement or similar. 21. The method of any one of claims 16-20, c h a r a c t e r i z e d i n that the serving means comprise design patterns, straw holes, perforations or similar. 22. The method of claim 18, 19 or 20, c h a r a c t e r i z e d i n that it comprises the step of: acting on a ball bearing connected to the folding ruler which ball bearing contacts a cam surface of the actuating means. 23. A position controlling arrangement for a packaging machine for packaging (100) pourable food products of the type wherein a continuos packaging material web (101) is longitudinally sealed to form a tube which is filled with the pourable product, which tube, at regularly spaced intervals, is clamped and sealed transversally by pairs of sealing jaws, wherein the material web is provided with serving means, such as e.g. designs, perforations, straw holes at substantially regular intervals, c h a r a c t e r i z e d i n that it comprises means for automatically adjusting the length of the path of the packaging material web (101) before clamping and sealing such that the position of serving means provided on the material web can be controlled to have a predetermined position on finished, sealed packages. 24. An arrangement according to claim 23, c h a r a c t e r i z e d i n that the position controlling means are arranged to act upstreams of the respective sealing jaws. 25. An arrangement according to claim 24, c h a r a c t e r i z e d i n that it comprises folding rulers (5;20) which are slidably arranged with respect to each sealing jaw provided on an endless chain for cooperating with sealing jaws on an oppositely directed endless chain and actuating means (40; 400) operable to adjust the length of the folding rulers (5;20). 26. An arrangement according to claim 25, c h a r a c t e r i z e d i n it further comprises driving means (41; 410) connected to a control unit (107) controlling the driving means (41;410) driving the actuating means (40;400), which control unit (107) receives signals from detecting means (105) arranged to detect the position of serving means or marking means, on the material web.

Inventors: PALMNAES MARKUS, PERSSON LARS-EBBE, PALMNAES, MARKUS, PERSSON, LARS-EBBE
Applicants: PALMNAES MARKUS, PERSSON LARS EBBE, TETRA LAVAL HOLDINGS & FINANCE, PALMNAES, MARKUS, PERSSON, LARS-EBBE, TETRA LAVAL HOLDINGS & FINANCE SA
Application year: 2001
Main classification: B65B9
IPC codes: B65B9, B65B57