An apparatus for continual application on a continuous material web

Abstract: The invention relates to an apparatus for the continual application of cut pieces of a strip to a continuous material web. The apparatus includes a station drum provided with a plurality of sealing devices. Via transport rollers, where the cutting of the strip also takes place, the strip pieces are transported to the sealing devices. The continuous material web is passing the sealing devices and the strip pieces are sealed to the material web. The material web is kept in register by means of a register maintenance device.

Description: TECHNICAL FIELD The present invention relates to an apparatus for the continual application of cut pieces of a strip to a continuous material web. BACKGROUND ART Within the packaging industry, it is common to provide a continuous material web with some form of strip in pieces. The strip pieces may, for example, constitute an opening arrangement in which the strip covers a pre-punched hole, a so-called pull-tab, or when the strip is placed in a sealing seam, a so-called spout strip. It may also be a case of application of strips in the form of labels or other identification. As regards application of strips which constitute opening arrangements, this normally takes place intermittently in that the web is arrested in its movement and the strip is sealed in place over a pre-punched hole, as disclosed in, for example, Swedish Patent Specification SE 317246. It is, however, desirable to increase the speed of this type of strip application and to render it continual. US-A-3 879 246 discloses an apparatus and method, adapted for continuously adhesively bonding relatively narrow elongated strips of flexible material cut from a parent sheet, to a web of material and applying such strips in spaced apart relationship on the web. The parent sheet is continuously fed from a roll in one general direction to a continuously rotating vacuum drum. Prior art still encompasses several disadvantages such as only one side of the web is applicable with strips or pieces of a strip or such as it is not possible to apply heat or pressure on the web for a longer period of time. Moreover, the application of the strip must at the same time be reliable and be able to locate the strip in its intended place. Furthermore, it must be capable of being adapted to rapid, modern filling machines and be capable of being integrated in them. OBJECTS OF THE INVENTION One object of the present invention is to devise a continual application of strip pieces on a continuous material web so that the speed of the filling machine need not be reduced as a result of this operational phase. Furthermore, application must take place exactly and be observing due maintenance of register. The apparatus must also be capable of being integrated or retrofitted in a filling machine and be capable in a simple manner of integration into the control system of the filling machine. SOLUTION These and other objects have been attained according to the present invention in that the apparatus of the type disclosed by way of introduction has been given the characterizing feature of claim 1. Preferred embodiments of the present invention have further been given the characterizing features as set forth in the appended subclaims. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS One preferred embodiment of the present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings, in which: Fig. 1 shows the apparatus in its entirety; Fig. 2 shows the station drum of the apparatus; and Fig. 3 shows the register maintenance device of the apparatus. The Drawings show only those parts and details essential to an understanding of the present invention. DESCRIPTION OF PREFERRED EMBODIMENT The apparatus as illustrated in its entirety in Fig. 1 is preferably integrated in a filling machine, suitably at that site where a material web 1 enters the filling machine and before the material web 1 reaches any possible sterilization bath. Thereafter, the material web 1 is formed into a tube, filled with the intended contents and cut into individual packages. The apparatus may naturally also be placed outside the filling machine and there prepare the material web 1 with application of the contemplated strip pieces. The major components of the apparatus, a station drum 2, means for displacing the material web, rollers for transporting the strip and a register maintenance device are preferably mechanically interconnected by belts or a common master shaft. The component parts can also be wholly or partly connected to separate drive units. The station drum 2 constitutes the central unit of the apparatus and is provided with a number of sealing devices 3 which are preferably axially disposed about the periphery of the station drum 2. In Figs. 1 and 2, a station drum 2 is shown with eight sealing devices 3. Naturally, the sealing devices 3 may be more or fewer in number. A large number of sealing devices 3 imparts to the apparatus a higher workrate at the same time as the station drum 2 and thereby the apparatus in its entirety will take up more room. The number of sealing devices 3 is selected in view of the speed of the packaging machine and the volume of those packages which are to be packed in the filling machine. The number of sealing devices 3 must also be so great that the sealing devices have time to execute a tight seal before the material web 1 leaves the station drum 2. A number of idlers 4 are placed between the sealing devices 3 on the station drum 2. The purpose of the idlers 4 is to prevent that part of the material web 1 which is not to be sealed from coming into unnecessary contact with the sealing devices 3 and in such instance becoming exposed to undesirable wear. The sealing devices 3 consist of two parts - an upper 5 and a lower 6 - each connected to a vacuum source. The upper part 5 of the sealing device 3 may assume two positions, an open position where the upper sealing device part 5 is spring-biassed and is located at its greatest distance from the lower part 6, and a closed position where the upper part 5 is lowered over the lower part 6. The lower part 6 is connected to a pneumatic piston and cylinder assembly (not shown) and may move between two positions, an activated position where the lower part 6 is located at its greatest distance from the centre point of the station drum 2 and a deactivated position where the lower part 6 is located most proximal the centre point of the station drum 2. Both parts 5 and 6 of the sealing device 3 are disposed to receive one or two strips and, with the aid of the vacuum source, to retain these on the two sealing device parts 5 and 6 prior to sealing on the material web 1. The means for displacing the material web consist of the extension of the sealing device 3 and are, in the preferred embodiment, thus placed about the periphery of the station drum 2. The displacement means consist of two parts 7 and 8 of which the upper part 7 is placed in the extension of the upper sealing device part 5 and the lower part 8 is placed in the extension of the lower sealing device part 6. When the upper sealing device part 5 is lowered over the lower sealing device part 6, the upper part 7 of the displacement means will thus be lowered over the lower part 8 of the displacement means. The displacement means are operative to grasp the material web 1 and draw the web through the apparatus. It is also possible to site the displacement means wholly separate and discrete from the sealing devices 3 and the station drum 2. The material web 1 is prepared for the apparatus in such a manner that, before the material web 1 reaches the station drum 2, it passes a hole-making unit (not shown). The hole-making unit, which may be of conventional type with a rotary punch against a counter roller, can be driven by the same common drive train as the other component parts included in the apparatus. The hole-making unit is placed such that it is adapted to the register length of the material web 1, i.e. the distance between two packages on the material web 1, so that the holes are always situated at their intended position. Rollers for transporting a strip 9 may consist of one or, as shown in Fig. 1, two separate units. The one unit is intended to cover the holes of the material web 1 from the outside of the package, the so-called pull-tab, which is torn off on opening of the package. The other unit covers the holes of the material web 1 from the inside of the package, the so-called cover strip which insulates the edges of the hole from the contents of the package. The rollers include a feed roller 10 which, by moving different distances, determines the length of the strip piece. A transfer roller 11, whose surface is provided with holes connected to a vacuum source, is operative to retain the strip 9 and the strip pieces on its surface. Further, the transport rollers include a knife roller 12 with a number of knives 13 placed about its periphery which cut towards the transfer roller 11. Where the knife roller 12 comes into engagement with the transfer roller 11, the transfer roller 11 may be provided with inlays of a harder material such as, for example, tungsten carbide. The transfer roller 11 is operative to move the strip piece further to the sealing devices 3. Since the knife roller 12 is not placed in the immediate vicinity of the hot sealing devices 3, the risk will be avoided that the knives become coated with molten thermoplastic. The apparatus also includes a register maintenance device. The continuous material web 1 is intended to be divided into separate packages and, since these carry artwork décor which is kept in register, it is desirable that the strip 9 always be situated at the same position on the package. The strip 9 must also be placed correctly in relation to any possible holes with regard to so-called pull-tab openings or with regard to a package seam for so-called spout strip opening. The register maintenance device according to the invention consists of a wheel 14 with a number of rollers 15 arranged axially. The rollers 15 may be three or more in number. Fig. 3 shows the wheel 14 of the register maintenance device with four rollers 15. The register maintenance device is disposed to execute not only a rotary movement but also a transverse movement in relation to the material web 1, so that it presses on the web 1. The transverse movement may be reversible and be rapidly modified with slight variations. The variations are between 0,05 and 0,1 mm. The material web 1 enters the filling machine from some form of magazine reel (not shown). For strip application relating to so-called pull-tab openings, the material web 1 first passes a hole-making unit (not shown). The location of the hole-making unit is determined by register length and other parts included in the apparatus. The material web 1 continuously runs through the apparatus at high speed and it passes into the apparatus under tension in order that the material web 1, on being bent, does so uniformly and with the same level of material consumption. The tension of the material web 1 may, for example, be realized by some form of magnetic brake. Simultaneously and likewise continuously, one or more strips 9 are fed into the apparatus from one or more magazine reels (not shown). The feed roller 10 of the strip 9 makes a predetermined stroke and feeds out as much strip 9 as is desired and transfers it to the transfer roller 11 on contact therewith. The transfer roller 11, whose surface is provided with holes connected to a vacuum source, retains the strip end. The transfer roller 11 coincides intermittently with the knife roller 12 which cuts off the strip end into a strip piece. The strip piece continues, retained by the vacuum apertures of the transfer roller 11, around the transfer roller 11 and to the sealing device 3. That sealing device 3 which is in turn to receive the strip piece or strip pieces is located in the position that the upper part 5 is open and separated from the lower part 6 and the lower part 6 is activated so that the lower part 6 is raised up from the surface of the station drum 2. Both of the strip pieces are retained by vacuum on the sealing devices 3. In those cases which relate to application of a so-called spout strip, the strip pieces enter axially towards the station drum 2 and it is then only one strip 9 that is applied. The station drum 2 rotates such that the sealing device 3 which received strip pieces approaches the material web 1. At this point, the lower part 6 of the sealing device 3 is deactivated so that the material web 1 will not disturb the strip piece fixedly retained there. At the same time, the upper part 5 of the sealing device 3 is lowered over the lower part 6 with the aid of, for example, a cam. In this instance, it is those two parts 7 and 8 of the displacement means which are placed in the extension of the sealing device 3 which are operative to displace the material web 1 by grasping the material web 1 and drawing it through the apparatus. The material web 1 is now located a distance into the apparatus retained by the displacement means parts 7 and 8 and surrounded on either side by a strip piece, the pull-tab strip and the cover strip, held on the surface of the sealing devices 3. The lower sealing device part 6 is now once again activated so that the cover strip is moved up towards the material web 1. The sealing devices 3 now execute a sealing operation and in this instance apply the strip pieces one from each side of the material web 1, with some form of heat sealing which may, for example, consist of induction heating or the like. The station drum 2 rotates constantly during this process and, in such instance, there will be obtained sufficient sealing time so that the strip pieces will also have time to cool and be retained on the material web surface without risk of subsequent leakage. Simultaneously with the above-described procedure, it is necessary that the material web 1 be kept in register such that the strip 9 is always sited at its intended position on the material web 1 and ideally over its intended hole. In such an instance, a roller 15 on the rotating register maintenance device wheel 14 moves transversely in towards the material web 1 and forces the material web 1 in between the sealing devices 3. How much of the material web 1 is forced in between the sealing devices 3 will depend on that read-off which takes place of the bar code of the material web, a code which indicates the register maintenance. Via an encoder, the register maintenance device is controlled so that the transverse movement in towards the material web 1 will be larger or smaller. The material web 1 departs from the apparatus at a slightly higher speed than it had on entry into the apparatus, with a view to counteracting slippage against the next sealing device 3. The material web now passes on through the machine to possible sterilization in the form of a sterile bath or the like in order subsequently to be formed into a tube, filled with the intended contents and cut off into individual packages. The apparatus according to the invention may suitably be controlled by the control system of the filling machine proper and otherwise requires slight supervision. In possible stoppage of the filling machine, that sealing device 3 which had commenced a sealing operation completes this operation and when the machine restarts, the next sealing device 3 starts in sequence. By such means, waste of packages will be reduced and at the same time the risk is avoided of obtaining packages which are not satisfactorily sealed in the opening arrangement. By varying the diameter of the station drum 2 and moving the other parts included in the apparatus in relation thereto, application can be effected at different register lengths and, thereby, different package sizes. By means of a number of interchangeable station drums 2, the commonest package sizes can be applied. As will have been apparent from the above description, the present invention realizes a continual apparatus for application of strip pieces to a continuous material web which can be utilised in today's rapid filling machines where it is required that the material web need not be stopped for this operational phase. Given that the apparatus is built into the filling machine, use will be made of the control system and possibly the driving power of the filling machine for the apparatus. Furthermore, an exact and reliable application will be obtained of the strip while retaining the printing register. As a result of the compactness of the apparatus with short distances between hole-making and sealing, and given that the pull-tab strip and cover strip are applied simultaneously, the number of "misapplied" packages is reduced.

Claims: An apparatus for the continual application of pieces of a strip (9) to a continuously moving material web (1), including means for displacing the material web (1), rollers (10, 11, 12) for transporting and/or cutting said strip (9), application means for applying the pieces of the strip (9) to the material web (1) and adjusting means for adjusting the material web (1) with respect to the pieces of the strip (9), characterized in that said application means consist of a plurality of sealing devices (3) which are placed on a station drum (2) about its periphery and which fixedly seal said pieces of the strip (9) to said material web (1), that said material web (1) is deflected by said station drum (2) so that said sealing devices (3) can execute the application of said pieces of the strip (9) and that said adjusting means consist of a register maintenance device (14, 15). The apparatus as claimed in claim 1, characterized in that said sealing devices (3) are placed axially about the periphery of said station drum (2). The apparatus as claimed in one of the preceeding claims, characterized in that said sealing devices (3) include a radially outer part (5) and a radially inner part (6), each connected to a vacuum source. The apparatus as claimed in claim 3, characterized in that said outer part (5) of the sealing device (3) is guided by a cam so that it can assume an open and a closed position. The apparatus as claimed in claim 4, characterized in that said outer part (5) is spring-biased in its open position and interacts with said inner part (6) in its closed position. The apparatus as claimed in one of the claims 3-5, characterized in that said outer part (5) and/or said inner part (6) are disposed to receive said pieces of said strip (9) to apply said pieces of said strip (9) to said material web (1). The apparatus as claimed in one of the claims 3-6, characterized in that said inner part (6) is connected to a pneumatic piston and cylinder assembly so that it can assume an activated and a deactivated position. The apparatus as claimed in one of the claims 3-7, characterized in that said inner part (6) is, in its activated position, located at its greatest distance from the center point of the station drum (2) and, in its deactivated position, located most proximal the center point of the station drum (2). The apparatus as claimed in one of the preceeding claims, characterized in that said station drum (2) is provided with a number of idlers (4) placed between said sealing devices (3). The apparatus as claimed in one of the preceeding claims, characterized in that said sealing devices (3) incooperate said means for displacing said material web (1). The apparatus as claimed in claim 10, characterized in that said displacing means consist of an axially outer part (7), connected to said outer part (5) and an axially inner part (8), interacting with said outer part (7). The apparatus as claimed in one of the preceeding claims, characterized in that said register maintenance device includes a wheel (14) with a plurality of axially disposed rollers (15). The apparatus as claimed in one of the preceeding claims, characterized in that said register maintenance device is operative to execute a rotary movement and a transverse movement in relation to the material web (1). The apparatus as claimed in one of the preceeding claims, characterized in that said register maintenance device is, on its transverse movement towards the material web (1), operative to variably force in the material web (1).

Inventors: UNTHANK ROBERT, UNTHANK, ROBERT
Applicants: TETRA LAVAL HOLDINGS & FINANCE, TETRA LAVAL HOLDINGS & FINANCE SA
Application year: 1993
Main classification: B31B1
IPC codes: B31B1, B65B61