Sealing device and method for ultrasonically sealing a fitting element to a workpiece - Patent application

Abstract

There is described and illustrated a sealing device (1) for ultrasonically sealing a fitting element (2) to a workpiece (3), in particular in the form of a composite laminate, comprising a sonotrode (5) for generating ultrasonic waves, a sealing surface (6) for transmitting the ultrasonic waves to the fitting element (2) and / or the workpiece (3), an anvil (7) opposite the sonotrode (5), and an adjustment device for adjusting the sonotrode (5) and the anvil (7) relative to one another from an open position for at least partially inserting the fitting element (2) and the workpiece (3) into a sealing gap (4) between the sonotrode (5) and the anvil (7), to a closed position for at least partially pressing the workpiece (3) and the fitting element (2) between the sealing surface (6) of the sonotrode (5) and the anvil (7) during ultrasonic sealing, and vice versa. In order to prevent damage and leakage in a workpiece such as a packaging laminate, for example in the area of ​​a fold line, due to ultrasonic sealing of a fitting element such as a spout to the workpiece or packaging laminate, at least one pair of opposing clamping means (10, 11) which are vibration-insulated from the sealing surface (6) are provided on both sides of the sealing gap (4) for clamping the workpiece (3) in the closed position, and the at least one pair of clamping means (10, 11) are provided outside the sealing surface (6) relative to the fitting element (2) when viewed in the direction along the sealing gap (4).

Description

[Technical Field]

[0001] The present invention relates to a sealing device for ultrasonically sealing an equipment element to a workpiece, in particular in the form of a composite laminate, comprising a sonotrode for generating ultrasonic waves, a sealing surface for transmitting the ultrasonic waves to the equipment element and / or the workpiece, an anvil opposite to the sonotrode, and an adjusting device for adjusting the sonotrode and the anvil relative to each other from an open position for at least partially inserting the equipment element and the workpiece into a sealing gap between the sonotrode and the anvil to a closed position for at least partially pressing the workpiece and the equipment element between the sealing surface of the sonotrode and the anvil, respectively, during ultrasonic sealing, and vice versa.Furthermore, the present invention relates to a method for ultrasonically sealing an equipment element to a workpiece, in particular in the form of a composite laminate. [Background technology]

[0002] The workpiece can be designed in the form of a packaging laminate. Such a packaging laminate is used to form packages for holding various products to be filled. Such products are usually food products, especially beverages, and can optionally have bulk components. As a rule, such products are pourable or free-flowing, especially flowable. Packages for holding food products with at least one liquid component are particularly suitable. Such packages are generally designed as so-called composite packages and are usually formed from a packaging laminate with a planar layer structure, especially a cardboard / plastic composite laminate.

[0003] Cardboard composite packages and cardboard / plastic composite laminates for producing such packages have a cardboard layer that provides the package with its basic stability and thus its basic structure. The cardboard layer thus forms a structural carrier layer. This carrier layer is at least largely responsible for, and particularly predominantly provides, the bending stiffness of the packaging laminate. In other words, packaging laminates and packages produced from these packaging laminates retain their shape thanks to the structural carrier layer. Additionally, an outer plastic layer, particularly a thermoplastic one made of polyethylene (PE), is usually provided. This plastic layer protects the cardboard from moisture and protects the food from absorbing undesirable substances from the package. Additional layers, such as an aluminum layer, may also be provided to prevent the diffusion of oxygen and other gases through the packaging laminate. Furthermore, the outer thermoplastic material layer allows the packaging laminate to be sealed to close the package and allows for the attachment of fittings, such as a spout, to the package. The packaging laminate also typically includes a printable decoration on the outer plastic layer, which decoration is generally much thinner than the actual outer plastic layer. The packaging laminate may further include other layers, such as an aluminum layer, which provide a barrier effect against gases and light.

[0004] The packaging laminate may be provided as a web or continuous material, particularly as a roll material. Packages may be formed directly from these materials without first fabricating a blank. The roll material is first bent and sealed along its longitudinal edges to form a tube, creating a liquid-tight seal along the length. Liquid-tight transverse seams are then sealed at regular intervals. The open-topped cylindrical pockets may then be filled with product. The cylindrical pockets are then sealed with subsequent transverse seams to form the package.

[0005] Alternatively, before the packaging is formed, the packaging laminate can be cut longitudinally and / or transversely to produce so-called blanks. These blanks can be further processed to form so-called packaging sleeve blanks in the form of packaging jackets or packaging sleeves. For this purpose, the longitudinal edges are placed one on top of the other and sealed together to form a longitudinal sealing seam. This results in a plurality of tubular packaging sleeves, which can be folded flat and stacked for further processing elsewhere, in particular in a filling machine. In the filling machine, the formed and filled packages can then be produced from the packaging sleeves.

[0006] The flat-folded packaging sleeves are transferred as a stack to a magazine of a filling machine, where they can be unfolded one after the other. This unfolding occurs along the pre-creased crease lines, which facilitate the creasing or folding of the packaging laminate. The corresponding crease lines are also known as score lines. The properly unfolded packaging sleeves are then folded, pressed, and sealed at one end. The sealed end of the packaging sleeve can then form the bottom or top of the package. The resulting open-sided packaging containers are fed into a filling machine, where they are preheated with hot, sterile air, then sterilized, typically with hydrogen peroxide, and dried with sterile air. The sterilized packaging containers are then filled. The openings of the filled packaging containers are then sealed, and the corresponding packages leave the filling machine.

[0007] To ensure that the packaging blank can be folded reliably, quickly, and easily to form the packaging sleeve, the bottom of the packaging container, and the top of the package, a plurality of score lines are provided in the packaging web. The packaging blank can be folded along these score lines. The score lines are typically stamped into the packaging web using a creasing tool. This results in the packaging web having depressions along the score lines on one side of the packaging web and ridges on the other side of the packaging web.

[0008] The top and bottom regions of the package are provided with a particularly large number of fold lines. These fold lines are required for folding the top and bottom of the package. In addition to the fold lines, a fitting element in the form of a spout is often attached to the top region of the package. The contents of the package can then be poured out through this fitting element. The spout generally has a base for the product to pass through and a flange for connecting the spout to the thermoplastic material layer of the packaging laminate. A lid may also be provided that is screwed onto the base to close the spout. Typically, a hole is provided in the packaging laminate, into which the spout is later attached from the inside or outside of the package. To seal the hole in the packaging laminate, the hole can be covered with another material, for example, an easily openable film, if necessary.

[0009] Spout attachment is typically accomplished by placing a spout flange around the hole in the packaging laminate and ultrasonically welding the flange to the adjacent thermoplastic layer of the packaging laminate. To this end, the packaging laminate and spout are pressed between an ultrasonic sonotrode and an opposing anvil, which partially heat the flange and / or adjacent layers of the packaging laminate, melting or at least softening them. As a result of the pressure applied to the packaging laminate and spout, the spout and the packaging laminate are welded together. However, this repeatedly damages adjacent fold lines, which can cause the packaging laminate to rupture, leak, and / or delaminate.

[0010] Similar problems can arise when sealing other equipment elements to the packaging laminate, such as lids, cutlery, straws, prizes, and the like. However, corresponding problems can also arise when sealing equipment elements to other workpieces. These other workpieces are preferably at least partially flat, and may be in the form of a laminate. It is advisable for at least some of their surfaces to be made of a thermoplastic material. In addition, these problems arise especially when discontinuities in the workpieces exist adjacent to the sealing location, preventing unrestricted transfer of vibrations and / or heat. Summary of the Invention [Means for solving the problem]

[0011] The present invention is therefore based on the object of designing and further developing a sealing device and method of the kind mentioned at the outset and described in more detail above, so that damage and leakage in workpieces such as packaging laminates, for example at fold lines, due to the sealing of fitting elements such as spouts to the workpieces or the sealing of packaging laminates by ultrasound, can be avoided.

[0012] This object is achieved in a sealing device according to the preamble of claim 1 in that at least one pair of opposing clamping means, vibrationally insulated with respect to the sealing surface, for clamping the workpiece in the closed position are provided on either side of the sealing gap, and that the at least one pair of clamping means are arranged outside the sealing surface relative to the mounting element, in particular the spout, when viewed in the direction along the sealing gap.

[0013] The object is furthermore solved according to claim 9, preferably according to any one of claims 1 to 8, by a method for ultrasonically sealing an equipment element to a workpiece, in particular in the form of a composite laminate, in which: - the fitting element and the workpiece are at least partially inserted into the sealing gap between the sonotrode and the anvil, respectively, and are pressed there between the sonotrode and the anvil; - the pressed workpiece is clamped against the equipment element between at least one pair of opposing clamping means on both sides of the sealing gap, outside the sealing surface; - When the workpiece is clamped, the sealing surface of the sonotrode, which is vibration-insulated relative to at least one pair of clamping means, transmits ultrasonic waves to the pressed fitting element and / or to the pressed workpiece, thereby sealing the fitting element and the workpiece together.

[0014] Thus, according to the invention, not only the workpiece, in particular in the form of a packaging laminate, but also the fitting element, in particular in the form of a spout, is pressed between the sonotrode and the anvil, so that the fitting element is sealed to the workpiece. The workpiece is also clamped between clamping means arranged on both sides of the sealing gap, and thus on both sides of the workpiece held in the sealing gap. When the sonotrode and the anvil are in the closed position, the fitting element is sealed to the workpiece, while the clamping means can also move together to clamp the workpiece. Since the clamping means is vibration-insulated from the sonotrode, ultrasonic waves are not transmitted to the workpiece significantly through the clamping means, as would be the case via the sealing surface of the sonotrode.

[0015] In addition, the clamping means is provided outside the area to be sealed relative to the equipment element. This does not necessarily mean that the clamping means clamps the workpiece outside the flange of the equipment element. The clamping means can also clamp the workpiece together with the flange of the equipment element, i.e. outside the area to be sealed, or at least outside the contact surface between the workpiece and / or equipment element on the one hand and the sealing surface of the sonotrode on the other hand. Outside the sealing surface means that the clamping means, whose clamping surface is in contact with the workpiece, is not arranged on the side of the sealing surface facing the central area of ​​the equipment element, but on the opposite side of the sealing surface.

[0016] From a procedural point of view, this is achieved by first at least partially inserting the equipment element and the workpiece into the sealing gap between the sonotrode and the anvil, where they are pressed together. During the ultrasonic sealing of at least the workpiece and the equipment element, the pressed workpiece is clamped against the equipment element between at least one pair of opposing clamping means on both sides of the sealing gap, i.e., at a location outside the sealing surface of the sonotrode. In this case, the sonotrode, which is vibration-insulated from the clamping means, can seal the workpiece pressed between the sonotrode and the anvil, as well as the equipment element, which is also pressed between the sonotrode and the anvil. This is achieved by the sealing surface of the sonotrode transmitting ultrasonic vibrations to the pressed workpiece and / or the pressed equipment element.

[0017] Ultrasonic waves are ultimately used to introduce the energy required for local sealing into the workpiece and / or equipment element. However, this corresponding energy is not only available in the area of ​​the sealing seam, but is also radiated to several other areas of the workpiece, even if the energy density in the workpiece decreases with increasing distance from the sealing surface of the sonotrode due to energy dissipation. However, the conduction of energy in the workpiece is terminated or at least greatly weakened, especially by the clamping of the workpiece. This energy cannot or cannot easily pass through the clamping area.

[0018] This energy is diffused through the workpiece, in particular by thermal conduction and by the conduction of ultrasonic vibrations. In the clamped area of ​​the workpiece, the conduction of ultrasonic vibrations is hindered because the clamped area cannot vibrate, or can vibrate only to a limited extent, due to the clamping. The clamped area of ​​the workpiece is therefore an obstacle to the vibration of the workpiece. Additionally, the clamping means can absorb a significant amount of the heat conducted by the workpiece. This means that only a much smaller portion of the heat is conducted away from the clamped area of ​​the workpiece. This heat conduction is therefore not prevented by the clamping itself. Heat is also conducted from the clamped area of ​​the workpiece. However, a significant portion of the heat conducted to the clamped area is removed from the workpiece by contact with the clamping means.

[0019] Therefore, clamping the workpiece prevents such high-density energy from being conducted to, for example, adjacent fold lines of the workpiece. Fold lines also present obstacles to the propagation of ultrasonic vibrations in the workpiece. This is because the workpiece is denser and harder in the fold line area. For this reason, vibration conduction in the fold line area of ​​the workpiece is significantly lower than in adjacent areas of the workpiece. Therefore, vibrations that reach the fold line are partially absorbed or partially reflected by the fold line. This directly causes mechanical stress on the fold line and indirectly causes heat generation at the fold line. In addition to this heat generation, there is also heat transported to the fold line by thermal conduction. Either of these, individually or together, can cause damage to the fold line. Consequently, if clamping means were not used as described above, this could lead to leakage, rupture, and delamination of the workpiece.

[0020] The above process for score lines can also occur at other discontinuities in the workpiece. Such discontinuities can be bends, grooves, tapers, openings, holes, joints, and the like. These elements can also be obstacles to the unrestricted propagation of ultrasonic vibrations and / or temperature in the workpiece. If necessary, the workpiece can also be a composite laminate. In such workpieces, the present invention can potentially prevent undesired delamination, i.e., separation of individual layers of the laminate.

[0021] Basically, the clamping force of at least one pair of opposing clamping means is established, which for general use may be between 10N and 150N, although clamping forces between 25N and 100N or between 45N and 70N may be particularly preferred.

[0022] For clarity and to avoid unnecessary repetition, the sealing device and method will be described together below without making a detailed distinction between them, although the features that are particularly suitable for each will be clear to those skilled in the art from the context.

[0023] In a first particularly preferred embodiment of the sealing device, the fitting element is designed as a spout and / or the workpiece is designed as a packaging laminate, particularly in the form of a cardboard / plastic composite laminate. In such cases, the advantages of the sealing device are particularly highly utilized, since otherwise the workpiece would be particularly easily damaged. The spout can also be used without a packaging laminate, and vice versa. The advantages are particularly evident when workpieces in the form of cardboard / plastic composite laminates are used, which are particularly prone to delamination. To produce cardboard composite packages, such workpieces are often first bonded at their fold lines, and then the fitting elements are bonded. This means that the attachment of the fitting elements can undesirably damage the fold lines. The corresponding workpieces, particularly cardboard / plastic composite laminates, have a cardboard layer. This cardboard layer, as a structural carrier layer, is intended to provide the basic stability and thus the basic structure of the package. In addition, an outer layer made of a thermoplastic material, for example polyethylene (PE), is preferably provided to allow sealing of the workpiece and to protect the cardboard from moisture. Additional layers, such as aluminum layers, can also be provided to prevent the diffusion of oxygen and other gases through the workpiece. At least one side of the workpiece can also be printed with a decoration or the like.

[0024] Alternatively or additionally, at least one pair of clamping means can be arranged at least approximately circumferentially around the sealing surface, facing the sealing gap, so that the sealing energy introduced by the sealing surface of the sonotrode in the region of the mounting element cannot be diffused outwards in all directions, or can be diffused to a lesser extent. For the sake of simplicity and to avoid stress peaks in the workpiece, it can also be advisable to arrange at least one pair of clamping means at least approximately annularly around the sealing surface.

[0025] For example, at least two pairs of opposing clamping means can be provided on both sides of the sealing gap to clamp the workpiece in the closed position. This is useful when multiple fold lines are provided adjacent to the equipment element only in specific directions. The diffusion of energy introduced during sealing only needs to be limited in these directions. The same applies when the workpiece has a fiber-containing layer, particularly a cardboard layer, with a preferred fiber direction, which may also be referred to as the main fiber direction. In this case, vibrations introduced into the workpiece are preferably conducted in the main fiber direction. This means that the propagation of energy introduced during sealing only needs to be limited in this main fiber direction, and if necessary, only from the central region of the equipment element to both sides. At least one pair of additional clamping means is also insulated from vibrations from the sealing surface. Each clamping means should not transmit any significant additional vibrations to the workpiece. Regardless of this, it is particularly advantageous when at least two pairs of clamping means are provided on both sides of the equipment element, outside the sealing surface, when viewed along the sealing gap. This prevents excessive propagation of sealing energy in both directions in the workpiece.

[0026] If at least one of the at least one pair of clamping means has an elastic portion, vibrations from the sonotrode can be further isolated. In this case, the vibrations from the sonotrode are absorbed at least to a large extent by the elastic material and thus removed from the system. Alternatively, or in addition, if necessary, a more secure clamping of the workpiece can be achieved. In this case, the elastic portion of the clamping means can serve to compensate for height differences of the workpiece in the clamping area. Thus, the workpiece can be clamped evenly and sufficiently at the same time. It is particularly simple and practical if the clamping surface of at least one clamping means for clamping the workpiece is provided by an elastic portion. Alternatively, the clamping surface should preferably be connected exclusively to other parts of the clamping means via the elastic portion. The elastic portion of the clamping means can also remove at least a portion of the vibration energy from the workpiece. Vibrations of the workpiece cause the elastic portion to vibrate. The elastic portion converts these vibrations into heat as a result of internal friction. The corresponding heat can then be transmitted to the environment or to other parts of the clamping means. It is generally a good idea to make the elastic parts out of a material with a low Young's modulus. 2 Less than 2.5N / mm 2 Less than 1.0N / mm 2 Preferably, the elastic portion has a hardness of between 20 and 100 Shore, in particular between 40 and 80 Shore, at which hardnesses adequate vibration damping behavior has been achieved.

[0027] For simplicity, at least one clamping means of at least one pair of clamping means assigned to an anvil can be designed as part of the anvil. This is particularly true if the corresponding clamping means has an elastic portion. In this case, further vibration isolation can be achieved. However, vibrations are usually transmitted to the anvil by the sealing itself via the mounting element and / or the workpiece. Therefore, further vibration isolation of at least one clamping means assigned to an anvil can usually be achieved if this clamping means is designed at a distance from the anvil in a direction at least approximately parallel to the sealing gap. As a result, no vibrations can be transmitted over this distance, especially if air or the like is provided between the anvil and the clamping means. Regardless of this, it can also be advantageous if the corresponding clamping means has an elastic portion. In this case, vibration isolation can be achieved at least for the workpiece. In this case, this vibration isolation simultaneously results in a pleasant vibration damping in the clamped area of ​​the workpiece.

[0028] Also with regard to the sonotrode, vibration isolation as far as possible can be particularly important. It can therefore be useful if at least one clamping means of at least one pair of clamping means assigned to the sonotrode is arranged at a distance from the sonotrode in a direction at least approximately parallel to the sealing gap, so that no vibrations can be transmitted over this distance, especially if there is air or the like between this clamping means and the anvil.

[0029] Alternatively or additionally, a vibration damper in the form of a robust component with increased inertia can be used to damp the vibrations. This is possible by fixing at least one clamping means of the at least one pair of clamping means to a vibration damper with a mass between 50 g and 400 g, preferably between 80 g and 300 g, in particular between 125 g and 225 g. This can be at least one clamping means assigned to the anvil and / or at least one clamping means assigned to the sonotrode, although the latter can be particularly useful. This is because the sonotrode generates ultrasonic waves that are transmitted from the sonotrode to the workpiece and / or the equipment element. In order for the vibrations to be damped by the vibration damper, mainly by inertia, the vibration damper should have a Young's modulus of at least 50,000 N / mm. 2 , preferably at least 100,000 N / mm 2 , especially at least 150,000 N / mm 2 It may be advisable to use a material that is

[0030] Regardless of this, it may be useful for uniform vibration damping if at least one clamping means of the at least one pair of clamping means is provided on a vibration damper that is arranged at least approximately annularly around the sonotrode and / or the sealing surface. Here, too, this at least one clamping means may be assigned to the anvil and / or the sonotrode. As mentioned above, since the sonotrode generates ultrasonic waves that are transmitted from the sealing surface of the sonotrode to the workpiece and / or the installation element, it may also be particularly useful here if a corresponding clamping means is assigned to the sonotrode.

[0031] To achieve the best possible clamping of the workpiece, taking into account possible tolerances or other deviations, it may be advisable to adjustably mount at least one clamping means, preferably pivotally or tiltably. This is particularly useful if at least one clamping means of at least one pair of clamping means is pivotally mounted relative to the sonotrode and / or the anvil about at least one pivot axis aligned at least approximately parallel to the sealing gap. This ensures good contact between the clamping means and the workpiece. This can be achieved particularly reliably if the clamping means is freely pivotable about this pivot axis. Since the sonotrode generates vibrations, it is preferable that a corresponding clamping means is assigned to the sonotrode. Alternatively or additionally, it is particularly advantageous from the viewpoint of vibration damping if the clamping means is pivotally mounted about at least one pivot axis together with a vibration damper.

[0032] To ensure a reliable and proper clamping, at least one clamping means of the at least one pair of clamping means can be spring-loaded at least approximately in the direction of the sealing gap, which ultimately allows the clamping force to be predefined or adjusted to a specific limit. For simplicity's sake, it is suitable to spring-load the clamping means together with a vibration damper. In this case too, particularly good results can be achieved if this clamping means is assigned to a sonotrode that causes vibrations.

[0033] In a first particularly preferred embodiment of the method, a spout is used as the fitting element and / or a packaging laminate, particularly in the form of a cardboard / plastic composite laminate, is used as the workpiece. In such cases, the advantages of the method are particularly highly utilized, since otherwise the workpiece would be particularly easily damaged. A spout can also be used without a packaging laminate, and vice versa. The advantages of the method are also particularly evident when a workpiece in the form of a cardboard / plastic composite laminate is used. Such workpieces are particularly prone to delamination. To produce a cardboard composite package, such workpieces are often first bonded at their fold lines, and then the fitting elements are bonded. This means that the attachment of the fitting elements can undesirably damage the fold lines. The corresponding workpiece, particularly a cardboard / plastic composite laminate, has a cardboard layer. This cardboard layer, as a structural carrier layer, is intended to provide the package with its basic stability and thus its basic structure. In addition, an outer layer made of a thermoplastic material, for example polyethylene (PE), is preferably provided to allow sealing of the workpiece and to protect the cardboard from moisture. Additional layers, such as aluminum layers, can also be provided to prevent the diffusion of oxygen and other gases through the workpiece. The workpiece can also be printed with a decoration or the like on at least one side.

[0034] Alternatively or additionally, the workpiece may be clamped by at least one pair of clamping means in longitudinally extending portions of the clamping means that are at least primarily transverse to the main fiber direction of the workpiece. This ensures that vibration and heat transfer that occurs primarily in the fiber direction due to the clamping means and the corresponding clamping of the workpiece is interrupted or at least significantly reduced. This is particularly true when the longitudinally extending portions of the clamping means are aligned at least approximately perpendicular to the main fiber direction of the workpiece, in particular cardboard. In many cases, not all fibers of a workpiece, in particular a cardboard layer of the workpiece, are aligned parallel to one another. Nevertheless, the majority and / or longest fibers of the workpiece, in particular the cardboard layer of the workpiece, will often be aligned at least approximately parallel to one another. In this case, this direction is considered the main fiber orientation.

[0035] Alternatively or additionally, it is advantageous if the workpiece is clamped by a clamping means between the fitting element and the score line of the workpiece, thereby preventing the energy introduced into the workpiece as vibrations and heat during sealing from being unrestrictedly conducted from the workpiece toward the score line, which could damage the score line and / or the workpiece. By clamping the workpiece by a clamping means, the conduction of energy is limited, at least to a large extent.

[0036] Since the score lines are often located on both sides of the equipment element, especially when viewed in the main fiber direction, it is advantageous to clamp the workpiece with clamping means on both sides of the equipment element, especially when viewed in the main fiber direction. In other directions, such as the direction perpendicular to the main fiber direction, clamping can be omitted in order to protect the workpiece there. This can be advantageous if the score lines are only located at a certain distance in these directions, or if the energy conduction perpendicular to the main fiber direction is so low that energy conduction there can be tolerated without having to worry about the score lines being damaged.

[0037] The diffusion of the energy introduced into the workpiece during sealing can be particularly easily and reliably limited if the workpiece is clamped by the clamping means in at least approximately the circumferential direction, thereby limiting diffusion in all directions. This can be achieved particularly easily and uniformly if the workpiece is clamped in at least approximately annular fashion around the sonotrode and / or the sealing surface.

[0038] To reduce vibrations overall and thus eliminate them from the system, at least one clamping means of at least one pair of clamping means can have at least one elastic part. In this case, this elastic part can be used to at least partially absorb ultrasonic vibrations during sealing. However, for this purpose, adequate contact with the workpiece is required to transmit the vibrations to the elastic part. This is particularly easy to achieve if the elastic part provides the clamping surface of the clamping means. Alternatively, the clamping surface should preferably be connected exclusively via the elastic part to other parts of the clamping means. Vibrations of the workpiece cause the elastic part to vibrate. These vibrations are converted into heat as a result of internal friction. The corresponding heat can then be transmitted to the surrounding area or other parts of the clamping means. It is generally a good idea to make the elastic part out of a material with a low Young's modulus. The Young's modulus of the material is preferably 5.0 N / mm. 2 Less than 2.5N / mm 2 Less than 1.0N / mm 2 Alternatively, the elastic portion may have a hardness between 20 and 100 Shore, in particular between 40 and 80 Shore, at which point adequate vibration damping behavior is achieved.

[0039] Instead of or in addition to proper absorption of vibrations, vibration damping can also be achieved. In the case of absorption, vibrations are converted into elastic deformation of the elastic part, which dissipates the corresponding energy. On the other hand, damping utilizes the inertia of a sufficient mass of the vibration damper. The vibration damper must also be in contact with the workpiece so that vibrations can be transmitted from the workpiece to the vibration damper. From a procedural point of view, vibrations transmitted from the sonotrode to at least one clamping means of the at least one pair of clamping means can be damped by a vibration damper supporting this clamping means and having a mass between 50 g and 400 g, preferably between 80 g and 300 g, in particular between 125 g and 225 g. This allows the energy to be sufficiently dissipated within the system, so that adjacent crease lines are protected from this energy. To enable vibrations to be damped by the vibration damper mainly by inertia, it may be advantageous to use a vibration damper with a Young's modulus of at least 50,000 N / mm 2 , preferably at least 100,000 N / mm 2 , especially at least 150,000 N / mm 2、 The goal is to manufacture vibration dampers using these materials.

[0040] Alternatively or additionally, it is advantageous if the vibrations transmitted from the sonotrode to at least one of the at least one pair of clamping means are damped by a vibration damper that extends circumferentially around the sonotrode supporting this clamping means. This results in an equalization of the vibration energy if the vibrations introduced during sealing are transmitted separately in different directions. This equalization is achieved to a particularly high extent if the vibration damper is designed to be at least approximately annular around the sonotrode.

[0041] To ensure sufficient contact between the clamping means and the workpiece, it is advantageous to pivot at least one of the at least one pair of clamping means about a pivot axis aligned at least approximately parallel to the sealing gap for clamping. This counteracts inaccuracies of the method or of the workpiece and contributes to a predetermined, uniform clamping. For simplicity and better vibration damping, at least one clamping means can be pivoted about a pivot axis aligned at least approximately parallel to the sealing gap together with a vibration damper.

[0042] At least one clamping means of the at least one pair of clamping means can at least partially clamp the workpiece with a clamping force at least partially formed by the restoring force of at least one spring means. This easily ensures, if necessary, that the workpiece is clamped with a clamping force sufficient to prevent the dissipation of energy introduced into the workpiece during sealing. This clamping force is not so great that it would damage the workpiece during clamping. It is advisable to apply a restoring force to the at least one clamping means by at least one spring means together with a vibration damper during clamping. This also ensures that vibrations transmitted from the workpiece to the clamping means are reliably and appropriately transmitted to the vibration damper.

[0043] The invention will be described below with reference to the drawings, which show only one embodiment, and in which the following figures are shown: [Brief explanation of the drawings]

[0044] [Figure 1A] 1 is a perspective view of a sealing device according to the present invention in an open position; [Figure 1B] 1 is a perspective view of a sealing device according to the present invention in an open position; [Figure 2] FIG. 2 is a top view of the anvil of the sealing device of FIG. 1. [Figure 3] FIG. 2 is a top view of the sonotrode and vibration damper of the sealing device of FIG. 1. [Figure 4A] 2 shows the sealing device of FIG. 1 in an open position during the implementation of a method according to the invention; [Figure 4B] 2 shows the sealing device of FIG. 1 in an open position during the implementation of a method according to the invention; [Figure 4C] 2 shows the sealing device of FIG. 1 in a closed position during the implementation of a method according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0045] 1A and 1B show a sealing device 1 for ultrasonically sealing a fitting element 2 in the form of a spout to a workpiece 3 in the form of a packaging laminate, in particular a cardboard / plastic composite laminate. The sealing device 1 provides a sealing gap 4 into which a portion of the workpiece 3 and a portion of the fitting element 2 can be inserted. A sonotrode 5 is provided on one side of the sealing gap 4. The sonotrode 5 generates ultrasonic vibrations which can be transmitted to the workpiece 3 via a sealing surface 6 of the sonotrode 5. An anvil 7 is arranged on the other side of the sealing gap 4, opposite the sonotrode 5. The anvil 7 can receive a flange 9 of the fitting element 2 in a receiving part 8. The sonotrode 5 then presses the workpiece 3 against the flange 9, while transmitting the ultrasonic vibrations to the workpiece 3, in order to seal the flange 9 of the fitting element 2 in the corresponding position on the workpiece 3.

[0046] At the same time, the clamping means 10, 11 of the two pairs of opposing clamping means 10, 11 clamp the workpiece 3 between each other to prevent the vibrations introduced into the workpiece 3 during sealing and the heat induced in the workpiece 3 as a result from it from being conducted almost unrestrictedly through the workpiece 3 in the direction of the adjacent fold lines 12. Otherwise, the energy of the workpiece 3 generated by the vibrations and heat could damage the fold lines 12. For example, the workpiece 3 could rupture, leak, and / or delaminate in the areas of the fold lines 12.

[0047] In the clamped area of ​​the workpiece 3, heat and vibrations are transferred from the workpiece 3 to the corresponding clamping means 10, 11, preventing significant transfer from the workpiece 3 to the outside. The clamping means 10, 11 are located opposite each other on either side of the sealing gap 4 and are therefore assigned to either the anvil 7 or the sonotrode 5. The clamping means 11 assigned to the anvil 7 is made of an elastic material, but in this case, not necessarily silicone. That is, the elastic portion 13 of the clamping means 11 also forms the clamping surface 14 of the clamping means 11. This prevents the clamping means 11 from transmitting vibrations unrestrictedly from the workpiece 3 to the anvil 7 or from the anvil 7 to the workpiece 3. These vibrations are partially absorbed by the clamping means 11, resulting in elastic deformation there. As a result, the vibration energy is absorbed in the clamping means 11.

[0048] In addition, vibrations transmitted by the fitting element 2 to the anvil 7 during sealing cannot be transmitted, or are transmitted only to a limited extent, to the workpiece 3 by the clamping means 11. These vibrations also cause elastic deformation of the clamping means 11 made of elastic material, and thus the corresponding energy is absorbed. This energy cannot therefore be transmitted from the anvil 7 to the workpiece 3 via the clamping means 11 assigned to the anvil 7. This ultimately results in the isolation of vibrations between the anvil 7 and the workpiece 3 via the clamping means 11 assigned to the anvil 7.

[0049] The clamping means 10 assigned to the sonotrode 5 is held by a vibration damper 15. The vibration damper 15 is arranged at a distance from the sonotrode 5, thereby insulating vibrations from the sonotrode 5 and its sealing surface 6. The vibration damper 15 itself is held so as to be freely pivotable on a pivot axis 16, which extends at least approximately parallel to the sealing gap 4. The clamping surface 14 of the clamping means 10 is therefore always aligned parallel to the workpiece 3 in order to clamp the workpiece 3 evenly across the entire clamping surface 14.

[0050] The pivot axis 16, and therefore the vibration damper 15, can be adjusted relative to the sonotrode 5 and the sealing surface 6 of the sonotrode 5 in a direction at least approximately perpendicular to the sealing gap 4. The vibration damper 15 is spring-loaded in the direction of the sealing gap 4. In other words, the vibration damper 15 can be moved away from the sealing gap 4 against the restoring force of the spring means 17. This limits the maximum clamping force between each pair of opposing clamping means 10, 11.

[0051] FIG. 2 shows the anvil 7 in a top view seen from the sealing gap 4. The anvil 7 has a receiving portion 8 that can accommodate the flange 9 of the fitting element 2. When sealing the fitting element 2 to the workpiece 3, the fitting element 2 is pressed against the receiving portion 8 of the anvil 7 via the workpiece 3 by the sonotrode 5. An opening 18 is provided in the receiving portion 8 of the anvil 7. A vacuum can be drawn into the receiving portion 8 through the opening 18 to securely hold the fitting element 2 in the receiving portion 8 of the anvil 7. Clamping means 11 assigned to the anvil 7 are arranged on both sides of the receiving portion 8 at a distance from the receiving portion 8. The clamping means 11 protrude slightly into the sealing gap 4 compared to the receiving portion 8. However, since the clamping means 11 are made of an elastic material, the clamping means 11 can be slightly compressed, for example, until they no longer protrude beyond the receiving portion 8 or until they no longer protrude significantly. The clamping surface 14 of the clamping means 11 can then be flush with the receiving part 8 of the anvil 7 and / or the flange 9 of the fitting element 2 .

[0052] FIG. 3 shows the sonotrode 5 together with the vibration damper 15 in a top view from the sealing gap 4. The sonotrode 5 has a central receiving portion 19 for receiving the portion of the fitting element 2 that protrudes outward across the workpiece 3. This portion of the fitting element 2 is preferably provided with a screw-on cap 20. The sealing surface 6 of the sonotrode 5 is arranged circumferentially around this receiving portion 19. The sealing surface 6 of the illustrated sonotrode 5, which is preferred in this regard, is annular. The sonotrode 5 presses the sealing surface 6 against the workpiece 3, which is arranged above the also annular flange 9, applying ultrasonic waves to the joint and thus sealing, i.e., welding, the joint. The vibration damper 15 is arranged around the sonotrode 5 and the sealing surface 6 at a distance from the sonotrode 5. The vibration damper carries two clamping means 10 designed to oppose the clamping means 11 assigned to the anvil 7. The clamping means 10 assigned to the sonotrode 5 is rigid and is held by an even more rigid vibration damper 15. In the preferred illustrated sealing device 1, the clamping means 10 assigned to the sonotrode 5 and the vibration damper 15 are made of metal, in particular steel.

[0053] The vibration damper 15 is provided circumferentially relative to the sonotrode 5 and the sealing surface 6 and is held in corresponding recesses in the sealing device 1 via two pins 21. These pins 21 define a pivot axis 16. The vibration damper 15 can be pivoted relative to the recess 22 about the pivot axis 16, at least approximately parallel to the sealing gap 4. The recess 22 can be adjusted slightly back and forth in the direction of the sealing gap 4, relative to the sealing surface 6. The recess 22 and / or the vibration damper 15 are spring-loaded by a spring means 17, so that the vibration damper 15 can be adjusted relative to the sonotrode 5 in a direction away from the anvil 7 against the restoring force of the spring means 17.

[0054] 4A-4C show various positions of the sealing device 1 during the sealing method. In FIG. 4A, the sealing device 1 is shown with the sonotrode 5 and anvil 7 in the open position. In the open position, the fitting element 2 can be inserted into the sealing gap 4 and the flange 9 can be inserted into the corresponding receiving part 8. The fitting element 2 is held in the position shown by applying a vacuum to the receiving part 8.

[0055] 4B, the workpiece 3 is then placed in the sealing gap 4 so that the fitting element 2 protrudes through the corresponding hole 23 in the workpiece 3. However, the workpiece 3 can also be positioned appropriately first. The fitting element 2 can then be inserted into the sealing gap 4 and pressed into the corresponding hole 23 in the workpiece 3. The workpiece 3 then covers the flange 9 of the fitting element 2 in the circumferential direction relative to the hole 23 in the workpiece 3.

[0056] At this point, the sonotrode 5 and / or anvil 7 can be adjusted relative to one another to the closed position, as shown in FIG. 4C. In the closed position, the sonotrode 5 is activated and transmits ultrasonic waves to the workpiece 3. The workpiece 3, together with the flange 9 of the fitting element 2, is heated in the region of the flange 9, thus forming a material bond between the workpiece 3 and the fitting element 2. At the same time, because the workpiece 3 is clamped between the clamping means 10, 11, ultrasonic waves and heat within the workpiece 3 can only be transmitted, if at all, to the fitting element 2, beyond the clamping of the workpiece 3 between the clamping means 10, 11. Therefore, the fold lines 12 in this region of the workpiece 3 are not excessively damaged by the sealing between the workpiece 3 and the fitting element 2. After sealing, the sonotrode 5 and anvil 7 are adjusted relative to one another back to the open position. The workpiece 3 can then be removed from the sealing gap 4 together with the fitting element 2 sealed to the workpiece 3. This completes the cycle, which can now be repeated to connect another workpiece 3 to the fitting element 2. [Explanation of symbols]

[0057] 1 Sealing device 2 Equipment element (spout) 3 Workpiece (packaging laminate) 4 Sealing gap 5 Sonotrode 6 Sealing surface 7 Anvil 8 Receiving part 9 flange 10 Clamping means (sonotrode) 11 Clamping means (anvil) 12 Fold lines 13 Elastic part 14 Clamping surface 15 Vibration damper 16 Pivot axis 17 Spring means 18 Opening 19 Receiving part 20 screw cap 21-pin 22 recess 23 holes

Claims

1. 1. A sealing device (1) for ultrasonically sealing an equipment element (2) to a workpiece (3), in particular in the form of a composite laminate, comprising a sonotrode (5) for generating ultrasonic waves, a sealing surface (6) for transmitting the ultrasonic waves to the equipment element (2) and / or the workpiece (3), an anvil (7) opposite the sonotrode (5), and an adjusting device for adjusting the sonotrode (5) and the anvil (7) relative to each other from an open position for at least partially inserting the equipment element (2) and the workpiece (3) into a sealing gap (4) between the sonotrode (5) and the anvil (7), to a closed position for at least partially pressing the workpiece (3) and the equipment element (2) between the sealing surface (6) of the sonotrode (5) and the anvil (7), respectively, during ultrasonic sealing, and vice versa. At least one pair of opposing clamping means (10, 11) that are vibration-insulated from the sealing surface (6) for clamping the workpiece (3) in the closed position are provided on both sides of the sealing gap (4), and the at least one pair of clamping means (10, 11) are provided outside the sealing surface (6) with respect to the equipment element (2) when viewed in a direction along the sealing gap (4), and a clamping means (10, 11) of the at least one pair of clamping means (10, 11) having an elastic portion (13) for isolating vibrations from the sonotrode (5), and the elastic portion (13) provides a clamping surface (14) of the clamping means (10, 11) for clamping the workpiece (3).

2. 2. The sealing device according to claim 1, characterized in that the fitting element (2) is designed as a spout and / or the workpiece (3) is designed as a packaging laminate, in particular in the form of a cardboard / plastic composite laminate, and / or the at least one pair of clamping means (10, 11) are arranged at least approximately circumferentially, at least approximately annularly, around the sealing surface (6) facing the sealing gap (4).

3. 3. The sealing device according to claim 1, wherein at least two pairs of opposing clamping means (10, 11) are provided on both sides of the sealing gap (4) to clamp the workpiece (3) in the closed position and are vibration-insulated from the sealing surface (6), and the at least two pairs of clamping means (10, 11) are provided on both sides outside the sealing surface (6) with respect to the equipment element (2) when viewed in a direction along the sealing gap (4).

4. 2. The sealing device according to claim 1, characterized in that of the at least one pair of clamping means (10, 11) assigned to the anvil (7), at least one clamping means (11), in particular with the elastic portion (13), is designed as a part of the anvil (7) or is spaced apart from the anvil (7) in a direction at least approximately parallel to the sealing gap (4).

5. 2. The sealing device according to claim 1, characterized in that at least one clamping means (10) of the at least one pair of clamping means (10, 11) assigned to the sonotrode (5) is designed to be spaced apart from the sonotrode (5) in a direction at least approximately parallel to the sealing gap (4).

6. 2. The sealing device according to claim 1, wherein at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11), in particular assigned to the sonotrode (5), is mounted on a vibration damper (15) arranged at least approximately annularly around the sonotrode (5).

7. 2. The sealing device according to claim 1, wherein at least one of the at least one pair of clamping means (10, 11), in particular assigned to the sonotrode (5), is pivotably arranged, in particular freely, relative to the sonotrode (5) and / or the anvil (7), in particular about at least one pivot axis (16) at least approximately parallel to the sealing gap (4), in particular together with a vibration damper (15), and / or wherein at least one of the at least one pair of clamping means (10, 11), in particular assigned to the sonotrode (5), is spring-biased, in particular together with the vibration damper (15), at least approximately in the direction of the sealing gap (4).

8. 10. A method for ultrasonically sealing an attachment element (2) of a sealing device according to claim 1 to a workpiece (3), in particular in the form of a composite laminate, comprising: - said fitting element (2) and said workpiece (3) are each at least partially inserted into the sealing gap (4) between the sonotrode (5) and the anvil (7) and are there pressed between said sonotrode (5) and said anvil (7); the pressed workpiece (3) is clamped between at least one pair of opposing clamping means (10, 11) on both sides of the sealing gap (4) and outside the sealing surface (6) relative to the fitting element (2); - when the workpiece (3) is clamped, the sealing surface (6) of the sonotrode (5), which is vibration-insulated with respect to the at least one pair of clamping means (10, 11), transmits ultrasonic waves to the pressed fitting element (2) and / or the pressed workpiece (3), thereby sealing the fitting element (2) and the workpiece (3) together; method.

9. - a spout is used as fitting element (2) and / or a packaging laminate, in particular in the form of a cardboard / plastic composite laminate, is used as workpiece (3), and / or the workpiece (3) is clamped by the clamping means (10, 11) of the at least one pair of clamping means (10, 11) in a longitudinal extension of the clamping means (10, 11) at least predominantly transversely, in particular at least approximately perpendicularly, to the main grain direction of the workpiece (3); and / or the workpiece (3) is clamped between the fitting element (2) and the fold line (12) of the workpiece (3); The method of claim 8.

10. - the workpiece (3) is clamped on both sides of the equipment element (2) by the clamping means (10, 11), Preferably, the workpiece (3) is clamped by the clamping means (10, 11) at least approximately circumferentially, in particular at least approximately annularly, around the equipment element (2); 10. The method according to claim 8 or 9.

11. 9. The method according to claim 8, wherein during sealing, at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11) absorbs the vibrations in an elastic part (13), in particular providing a clamping surface (14).

12. 9. The method according to claim 8, wherein the vibrations transmitted from the sonotrode to the at least one clamping means of the at least one pair of clamping means are damped by a vibration damper supporting the clamping means and extending at least approximately annularly around the sonotrode.

13. 9. The method according to claim 8, wherein for clamping, at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11), in particular together with a vibration damper (15), is pivoted about a pivot axis (16) aligned at least approximately parallel to the sealing gap (4).

14. 9. The method according to claim 8, wherein the at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11) at least partially clamps the workpiece (3) with a clamping force formed at least partially by the restoring force of at least one spring means (17), in particular together with a vibration damper (15).

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