EP0475095A1 - Device for aligning a continuous web of foil with respect to another band - Google Patents

Abstract

An independently correcting device for shortening a web (1) by folding with the aid of a toothed roller (7) provided with recesses. The web (1) runs through at a nip between the toothed roller (7) and an opposing, driven second roller (5), which is provided with an elastic sleeve (8). If a shortening of the web is necessary, the web (1) is folded by a toothed roller (7) and the opposite elastic second roller (5) is overridden compared to the normal feed movement of the web. Further web shortenings can be achieved by selective pressure increase between the toothed roller (7) and the elastic drive roller (5), which deepens the folds in the web. The toothed roller (7) can be used together with a tension roller (3) which can be used specifically to stretch the web (1) and to achieve an elongation. Both rollers can be attached to a common housing, which is pivotable relative to a frame-attached drive roller. In this way, depending on the position of the housing, either the tension roller or the toothed roller can be brought into contact. The housing is moved by a pressure trigger, which is controlled by an electronic control device that detects the misalignment of the web at the working point. <IMAGE>

Description

The present invention relates to a device for checking and aligning the length of a first continuous film web relative to a second web to which it is connected, in particular a second continuous film web in which pockets for receiving objects are preformed to form a finished package.

There has long been a need to glue individual continuous film webs together, with alignment and coordination in the longitudinal direction having to take place between the two webs so that they are joined together at the desired location. This is most frequently the case with webs that require the periodic structure or a printed periodic pattern of one web to be assigned to an associated structure or pattern of the second web. The length of the corresponding pattern is called the period length. The period length of one path is often kept constant and used as a reference for the second path. This is called the design period length. The printed pattern on the second path, which is to be adapted to the design period length, is called the actual period length of this path. Exact alignment between two connected tracks requires that the actual period length be kept identical to the design period length.

The use of pre-printed material in a continuous film web is desirable for economic reasons; however, since the web is of continuous length and is only cut after gluing, there is a problem in adapting the actual period length to the design period length without interrupting the work process. This problem is generally solved in that at least one web is made of stretchable material and the period length of this web is selected to be significantly shorter than the design period length. By applying tension to the stretchable material during the work process, the undersized period length on that fabric is increased until it matches the actual design period length required for the second web. For this purpose, it is known to change the tension of a stretchable sheet to change the design period length. This allows adjustments to be made due to fluctuations in the production of the web and other manufacturing sizes that require adjustment and correction.

However, problems arise when some web materials, e.g. Aluminum foil, are only slightly stretchable. This allows the alignment of the tissue by stretching only to a very small extent. There has long been a search for a way to change the actual period length of a preformed continuous web in motion with respect to a preformed second web when both tissues are not readily stretchable.

Older patents that are relevant but do not anticipate applicant's invention are US Patent 3,762,125 - Prenna, "Film Aligner"; U.S. Patent 3, 294,301 - Richter, "Foil Alignment System"; U.S. Patent 3,589,095 - James, "Method and Apparatus for Aligning Two Individual Sheets of Cardboard Material" and U.S. Patent 4,704,171 - Thompson and Others, "Adhesive Device with Paper Tension Control".

In an effort to solve the unfulfilled need described above, the present device is proposed, in which the web to be bonded is guided over a toothed roller which introduces transverse folds into the tissue and thereby shortens in the longitudinal direction. These folds easily cause permanent adjustment, especially when the web is made of a certain material, such as aluminum foil. The toothed roller has a plurality of circumferentially arranged and extending teeth and depressions which are located between these teeth and extend essentially over the entire width and which corresponds approximately to the width of the web.

In the present invention, the correction roller opposite to the toothed roller is driven by a motor at a higher speed than the conveying speed (overdriven). In this way, the web material is accumulated in the recesses of the toothed roller and folds are formed in this material. Even though the material is deformed, it is more of a compression and accumulation of the material than a stretching operation. As a result, excess material is collected on a given path length as it is advanced behind the sprocket.

The amount of the web shortening due to the overdriven correction roller can be partially regulated by changing the contact pressure of the tooth roller on the opposite deformable elastic roller. In this way the depth of the folds and consequently the shortening of the web is changed. As will be further explained, this system can be used alone or preferably together with the known web stretching techniques described above. This allows better control of the reduction in tension that is required with slightly stretchable material. Although the actual cut in Period length can be achieved without strongly pressing the web to be bonded, a much lower force is required to change the actual period length when combining the two systems. If both systems are combined, a lower tension is used to increase the length of the period, whereas the folding process is somewhat increased to shorten the length of the web.

The present device is constructed mechanically in such a way that it allows the use of both systems in an easily controllable and compatible manner. As will be described further, a simple mechanical device allows the alternating use of either the tensioning or the folding function in a web processing station, which consists of special rollers and a trigger. An electronic control device, which is provided with sensors for detecting misalignments of the web, is used to indicate the drive speed or the braking of a correction roller in the web processing station. At the same time, the control device adjusts a trigger designed as a roller, which controls a mechanical displacement device, which in turn causes the tensioning or folding roller to bear more or less strongly on the correction roller. During use, it has been found that the alignment can be accomplished by folding without unduly distorting the appearance of the bonded web. If unacceptable distortions occur, this only happens for a short piece of the processed web.

It is therefore an object of the present invention to provide a regulating system for the period length of a preformed, slightly stretchable continuous web.

Another object of the invention is to provide a web processing station which allows regulation of the period length at a very low tension in a continuously preformed and stretchable web.

Another object of the invention is to provide a mechanical system with folding and tensioning rollers which is controlled by a simple, economical and easily controllable release mechanism.

• Figur 1 ist ein Diagramm, das die Anordnung der neuen Bahnbearbeitungsstation in einer typischen Verpakkungsmaschine zeigt.
• Figur 2 ist eine Seitenansicht in Querschnittsdarstellung der Auslösevorrichtung für die Zahn- und Spannwalze.
• Figur 3 ist eine Draufsicht auf die aus Zahn-und Spannwalze bestehende Anordnung.
• Figur 4 ist ein Flußdiagramm, welches die Verbindung des Kontrollkreises zwischen den Sensoren und der Bearbeitungsstation zeigt.

Additional details and advantages will be apparent to those of ordinary skill in the art from the following drawings and descriptions of preferred embodiments. Show it:

• Figure 1 is a diagram showing the arrangement of the new web processing station in a typical packaging machine.
• Figure 2 is a cross-sectional side view of the triggering device for the tooth and tension roller.
• FIG. 3 is a top view of the arrangement consisting of toothed and tensioning roller.
• Figure 4 is a flow diagram showing the connection of the control circuit between the sensors and the processing station.

With reference to FIG. 1, the present web processing station is arranged between a feed roller (2) and an adhesive roller (13) which meets the packaging (second) web (23). The web processing station is shown schematically in this figure and consists of a roller adjustment mechanism which moves the web (1) against a speed-controlled correction roller (5). A pre-printed or preformed adhesive web (1) is guided counterclockwise by a feed roller (2) over a toothed roller (7) and over the back of an elastic correction roller (5). The web then leads between guide rollers (11 a) and (11 b) down to the adhesive roller (13), which brings the treated web (1) into contact with the packaging web (23).

The photo sensors (15a and 15b) are arranged opposite one another on the web to be glued and the packaging web (23) in order to detect any relative misalignment. The sensors are electrically connected to a control device (29), which in turn is connected to a pressure regulator (19).

Referring now to Figure 2, a cross-sectional view of the web processing station is shown in an enlarged view. The roller trigger (21) is a pneumatic cylinder, which receives its air from the pressure regulator (19), which in turn is connected via a line (17) to an air supply according to the arrow in this figure. The air pressure moves the piston (15), which rests on the rocker housing (9). This rocker housing (9) carries both the tensioning roller (3) and the toothed roller (7), which are rotatably mounted. The rocker housing (9) is pivotable about a shaft (10) which is fastened to the housing (6) and represents a displacement mechanism between positions as described below. The correction roller (5) is rotatably fastened in the frame (6) and driven via a motor N, as shown in Figure 1. The rocker housing (9) is forced in the clockwise direction by a spring (27). As is immediately understandable for an average mechanic, when the air pressure behind the piston (15) increases, the toothed roller (7) comes out of contact with the correction roller (5). When the pressure increases further, the rocker housing (9) is moved further away, the tensioning roller (3) generates a clamping which defines the web (1) between itself and the driven correction roller (5). Because of these mechanical conditions, the movement of the rocker housing (9) allows the engagement of the toothed roller (7) or tensioning roller (3) to be set independently of one another in a selective manner.

The correction roller (5) has an elastic sleeve (8), which deform when the widthwise recesses of the toothed roller (7) are pressed, so that the web (1) is pressed into the recesses of the toothed roller in this way. In this way, folds or kinks are created in the web, as shown by the cross-sectional representation of the treated web (1 a) in FIG. 2. In this drawing, the folds have been exaggerated for clarity. In reality, the pits are only about 0.015 inches deep, the correction roller is about 2.5 inches in diameter. The number of pits per inch can range from 30 to 50 teeth using 0.003 inch thick aluminum foil.

Figure 3 is a top view of an apparatus shown from the side in Figure 2. In this figure the various structures can be seen more easily, which are held on a shaft between the frame end plates (6) and move therebetween.

In an alternative embodiment, the tensioning roller can also have teeth and depressions similar to the toothed roller. It has been found that using a toothed roller instead of a smooth surface roller to create tension increases web stretch for certain web materials. When the roller is pressed against the web with teeth in this arrangement and when tension is applied to either side of the clamp, the force in the indentations of the web is aimed at stretching rather than folding.

• a) eine Position, in welcher die Korrekturwalze
• (5) in Kontakt mit der Spannwalze (3) ist;
• b) eine Position, in welcher die Korrekturwalze
• (5) an der Faltwalze (7) in Kontakt steht;
• c) eine Position, in welcher die Korrekturwalze
• (5) weder mit der Spannungswalze (3) noch mit der Zahnwalze (7) in Kontakt steht oder beide gleichzeitig bei geringem Druck berührt.

The air pressure actuation of the roller trigger (21) of the web processing station will bring the combination of the rollers into one of the three functional positions:

• a) a position in which the correction roller
• (5) is in contact with the tension roller (3);
• b) a position in which the correction roller
• (5) on the folding roller (7) is in contact;
• c) a position in which the correction roller
• (5) is neither in contact with the tension roller (3) nor with the toothed roller (7) or touches both at the same time at low pressure.

As soon as one of these positions is taken, the correction roller (5) is driven or braked at an appropriate speed. The correction roller speed is generated by a suitable drive; for example the motor (M) -brake B-clutch C combination, which is best known from web control, which is described in the manner of a diagram in FIG. 1. The speed of the correction roller (5) can be changed by the strength of the electrical current to the clutch, which is indicated by an electronic control device, in order to generate the changing correction value in the desired manner.

In each of these three functional positions of the web processing device mentioned above, the manner in which this system operates is described in more detail.

In the first of these three positions, a clamping between the tension roller (3) and the correction roller (5) is generated. In this position the tension on the web can be increased by braking the correction roller (5) in order to make its surface speed lower than that of the packaging web (23). The level of braking and the resulting voltage is controlled by regulating the electrical current to the clutch, which is attached to the engine brake. At this moment, the movement of the packaging web, the adhesive web, is drawn between the tensioning roller and the correction roller at a speed greater than the clamping allows to increase the tension on the intervening web. This creates an elongation of the web and an increase in the actual period length at the glue point.

The second position of the above-mentioned web processing device is when the correction roller (5) is in contact with the tooth roller (7) and at a distance from the tension roller (3). In this case, the correction roller (5) is driven by means of a motor N with a linear surface speed which is greater than that of the adhesive web (23) (overdriven). The excess material is collected and piled up in the recesses of the tooth roller as the web passes the tooth roller kink. As can be seen more clearly from FIG. 2, in which the rollers are in this position, the indentations of the toothed roller cause the web to fold and kink in order in this way to shorten the length.

In this second position, an additional shortening of the web can be achieved by further reducing the pressure of the roller trigger. If the pressure of the rocker housing is reduced in this position, the force of the spring (27) is increasingly transmitted to the nip point between the two rollers in order to trigger an even greater deformation in the elastic surface of the correction roller (5). In this way, the folds and creases in the web become deeper and the length of the web is therefore shorter. The change in the pressurization of the whale zenauslösers (21) causes a greater shortening of the processed path after the rocker housing has been moved to the second position.

In the third functional position of the rocker housing, no strong clamping is generated between the correction roller and another roller, and consequently the adhesive film is pulled through the adhesive device with little or no tension. In order to minimize the movement of the seesaw housing, the rollers are preferably dimensioned so that both the toothed and tensioning rollers are in contact with the correction roller at the same time, but only a slight pressure between the elastic surface of the correction roller and each of the rollers prevails in both clamping points. With this arrangement, the web is never completely detached from both clamping points at the same time. A minimum tension between the guide roller (12) and the tension rollers (11 and 11 b) is generated to control the displacement of the web in the width. In this third position, the correction roller is indicated by the control unit when the wheel is to be released or when it is to be driven at the working speed. In this case, the pre-printed period length remains unchanged.

In summary, the various units of the web processing device work together in such a way that when the speed of the correction roller (5) and the air pressure acting on the roller trigger (21) changes, the length of the web (1) is either stretched or shortened in order to align it with the packaging web ( 23) in the desired way. The speed of the correction roller and the air pressure acting on the web processing station is determined by a control unit which is set via sensors (15a and 15b), as shown in FIG. The sensors are addressed by means of web markings which are arranged equidistantly on both the adhesive and the packaging web. The photo sensors are positioned so that the actual alignment takes place when both sensors are triggered by their corresponding markings at the same time.

As shown in FIG. 4, the sensors are connected to an electronic control device (29) which has a circuit which determines the sequence in which the sensors respond and the interval between them. The response order determines the direction of the correction required, while the time interval indicates the amount. These parameters are entered into a calculation method derived from experience, which changes the correction roller speed and the air pressure to produce the desired compensation. These two variables set by the control device determined the shortening and lengthening of the web in order to bring it into the correct orientation for gluing.

The circuit of the control unit is shown diagrammatically and generalized in FIG. Special circuits for achieving a programmable control unit with functional sequences according to the invention and explained here using a diagram are known. Therefore, the special circuits and electronic components can be selected from the large number of suitable components known to the electronics engineer.

Functional flow

If the registration sensor indicates that the adhesive web is moving relative to the packaging web, then the roller pressure trigger and the drive are actuated simultaneously as follows. The air pressure acting on the roller trigger is increased until the pretensioned spring is overcome so far that the tension roller (3) comes into contact with the correction roller and the web in between is detected. When the motor brake is actuated, the electrical supply to the clutch of the correction roller is increased in order to slow down the speed of the adhesive web so that it moves forward by a certain amount slower than the speed of the packaging web. In this way, tension of the web between the tension roller and the glue point is created by the pull of the forward movement of the packaging web. The tension then increases the length of the web by stretching. In this way, markings and other special parts of the adhesive web on the packaging web are moved to a point behind that where they would come to rest without increased tension. This creates the necessary spatial delay that is necessary to compensate for the detected feed.

Conversely, if the sensor detects that the adhesive tape remains behind the packaging film, the control unit responds as follows: The correction roller drive is shown that it is driven by a motor at a speed which is greater than the feed of the packaging sheet (overdriven) . With this mode of operation, the motor runs at a constantly high speed and the clutch current is increased in order to achieve the desired degree of oversteer. At the same time, the air pressure acting on the roller release is reduced. Now the spring on the rocker housing overcomes the air pressure and pushes the rocker housing until the tooth roller comes in close contact with the correction roller. This creates kinks and creases in the fabric which, as described in detail above, cause the web to be shortened. The pre-printed areas of the web are thereby caused to coincide with areas on the packaging web that are in front of those where they would normally be placed. In this way, the detected delay is corrected.

As described above, when the sensors detect either the advance or the retardation of the adhesive tape, the necessary corrections are made and the system becomes self-correcting. The electrical current to the clutch and the change in the roller release pressure are the variables that are set by the control units to achieve these results. In this way, a precise alignment between the adhesive web and the packaging web can be achieved and maintained by a suitably programmed control unit which carries out the desired changes in the correction roller drive and the roller trigger pressure.

One of ordinary skill in the art should understand that many of the simple mechanical designs described in the preferred embodiment have numerous alternatives that result in the same result. For example, the correction roller in the preferred embodiment is determined by a drive that is mechanically connected to both a clutch and a brake. In this case, the speed of the correction roller is controlled by the electrical supply to the clutch and the brake, which ensure that the drive system either over-rotates or brakes the roller. However, other suitable, variable speed drives can be used. Similarly, the preferred alignment control unit can be replaced by other deviation detection and control systems and by using other types of sensors from the prior art circuitry. The specific configurations shown here are shown for the purpose of illustration and only as one way of carrying out the invention. There may be other modifications and changes obvious to one of ordinary skill in the art that fall within the scope of the present invention and which should only be limited by the following claims and their legal equivalents.

Claims (10)

1. Device for checking and aligning the length of a first continuous film web relative to a second web to which it is connected, in particular a second continuous film web, in which pockets for receiving objects are preformed to form a finished package, consisting of a) a framework b) a toothed roller (7) which is rotatably mounted in this frame and is in contact with the first web (1) across the width; c) a correction roller (5) which is rotatably mounted in this frame and which, together with the toothed roller (7), clamps the first web (1); d) this toothed roller (7) has a width which is approximately equal to the width of the first web (1) and a plurality of circumferentially attached and extending teeth and recesses between these teeth, these teeth and recesses essentially extend over the entire width of this toothed roller (7) and e) Means for overriding this correction roller (5) relative to the speed of the second web (23), so that when the first web (1) passes this nip, folds running across the width are produced in the first web (1) , shortening their length. 2. Device according to claim 1, characterized in that the correction roller (5) is provided with an elastic sleeve. 3. Apparatus according to claim 1 or 2, characterized in that a tension roller (3) is fixed in this frame and selectively abuts the first web (1), the first web (1) between this tension roller (3) and the correction roller is held. 4. The device according to claim 3, characterized in that the tensioning roller 3) and the (7) toothed roller are fastened in a seesaw housing (9) which can be pivoted in this frame relative to the correction roller (5), the seesaw housing (9) through a roller trigger (21) can be actuated. 5. Device according to one of claims 1 to 4, characterized in that the correction roller (5) has speed control devices which provides a roller speed for oversteering or decelerating the correction roller (5) relative to the speed of the second web (23). 6. Device according to one of claims 1 to 5, characterized in that two sensors (15a, 15b) are present, each of which is assigned to a path (1,23) in order to avoid misalignments between the first (1) and the second path ( 23), the sensors (15a, 15b) being connected to a control device (29) which varies the speed of the drive and adjusts the roller trigger (21) either for stretching or for folding and oversteering the first web (1). 7. The device according to claim 6, characterized in that the control device (29) has electronic circuits which detect the time sequence and the time delay between the sensor signals in order to determine the direction and the amount of compensation required. 8. Device according to one of claims 1 to 7, characterized in that the roller trigger (21) is in connection with a pressure regulator (19) which is controlled via the electronic control device (29), so that a variable pressure between the toothed roller (7th ) and the correction roller (5) can be exercised selectively and determined by this control unit. 9. Device according to one of claims 3 to 8, characterized in that the tensioning roller (3) has different teeth and recesses over the circumference, which extend substantially over the entire length of the tensioning roller (3). 10. Device according to one of claims 1 to 9, characterized in that two sensors (15a, 15b) one on each track (1, 23) is arranged, which misalignment between the first (1) and the second track (23rd ), these sensors (15a, 15b) being connected to a control device (29) for overriding the correction roller (5).

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