Sealing device and method for sealing equipment elements on workpieces by means of ultrasound

Description

[0001] The invention relates to a sealing device for sealing accessories to workpieces, in particular in the form of a composite laminate, by means of ultrasound, comprising a sonotrode for generating ultrasound, a sealing surface for transmitting the ultrasound to the accessories and / or the workpiece, an anvil opposite 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 accessories 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 accessories between the sealing surface of the sonotrode and the anvil during ultrasonic sealing and back.Furthermore, the invention relates to a method for sealing equipment elements to workpieces, in particular in the form of a composite laminate, using ultrasound.

[0002] Document US6085489 discloses a device and a method for sealing spouts on packing laminates using ultrasound.

[0003] Workpieces can be designed in the form of packaging laminates. These packaging laminates serve to form packages for various products to be filled. The products are usually foodstuffs, particularly beverages, which may contain lumps as required. Generally, the products are free-flowing or pourable. Packages for containing a foodstuff with at least one liquid component are particularly preferred. These packages are typically designed as composite packages, which are generally formed from packaging laminate, especially a cardboard / plastic composite laminate, with a planar layer structure.

[0004] Cardboard composite packaging and cardboard / plastic composite laminates used to manufacture such packaging have a cardboard layer that provides the packaging with its basic stability and thus its fundamental structure. The cardboard layer therefore forms the structural support layer, which at least significantly determines, but in particular provides the vast majority of, the flexural rigidity of the packaging laminate. In other words, the packaging laminate and the packaging made from it retain their shape due to this structural support layer. In addition, outer plastic layers, especially thermoplastic ones such as polyethylene (PE), are usually included. These plastic layers protect the cardboard from moisture and the food from absorbing unwanted substances from the packaging. Further layers, such as an aluminum layer, may also be included to prevent the diffusion of oxygen and other gases through the packaging laminate.Furthermore, outer thermoplastic layers allow the packaging laminate to be sealed for closing the packages and for attaching features such as spouts. Packaging laminates are also usually printed with a design that can be applied to an outer plastic layer, with the design typically being much thinner than the actual outer plastic layer. The packaging laminate may also include additional layers, such as an aluminum layer that provides a barrier against gases and light.

[0005] The packaging laminate can be supplied as a web or continuous material, particularly as roll stock, from which packaging can be formed directly without the need for initial cutting. The roll stock is first folded over and sealed along its longitudinal edges to form a tube, then sealed lengthwise to be liquid-tight. Liquid-tight transverse seams are then sealed at regular intervals. Product can then be filled into the open-topped tube pouches before the pouches are sealed into packages by the next set of transverse seams.

[0006] Alternatively, the packaging laminate can be cut lengthwise and / or crosswise before the packaging is formed, creating so-called blanks. These can be further processed into so-called packaging sleeve blanks. For this, the long edges are overlapped and sealed together, forming a longitudinal seam. This produces tubular packaging sleeves, which are then folded flat and stacked for further processing at another location, particularly in a filling machine. In the filling machines, the packaging sleeves can then be used to produce a formed and filled package.

[0007] The flat-folded packaging sleeves can be fed as a stack into a magazine of the filling machine and unfolded one after the other. Unfolding takes place along pre-creased lines, where the packaging laminate can be easily creased or folded. These crease lines are also known as scoring lines. The unfolded packaging sleeve is then folded at one end, pressed, and sealed. The sealed end of the packaging sleeve can later form the bottom or top of the package. The resulting open-ended packages are fed into a filling machine, where they are preheated with hot sterile air and then sterilized, typically with hydrogen peroxide, and dried with sterile air. The sterile packages are then filled, after which the opening of the filled packages is sealed before the package leaves the filling machine.

[0008] To ensure that the folding of the packaging material blank into a package shell, base, and top is reliable, quick, and easy, the packaging material web is provided with scoring lines along which the blanks can be folded. These scoring lines are typically embossed into the packaging material web using scoring tools, with the web having a depression on one side and a raised area on the opposite side along the scoring lines.

[0009] Particularly in the top and bottom areas of the packages, numerous crease lines are provided, as these are necessary for folding the top and bottom of the packages. In addition to the crease lines, a spout is often attached to the top of the package, allowing the contents to be poured out. These spouts typically consist of a body for guiding the product and a flange for connecting the spout to a thermoplastic layer of the packaging laminate. A cap may also be included, screwed onto the body to close the spout. Usually, a hole is provided in the packaging laminate through which the spout is attached, either from the inside or the outside of the package.The hole can be covered with another material to close the hole in the packaging laminate, for example with a film that can be easily opened if necessary.

[0010] The spout is typically attached by placing its flange around the hole and then ultrasonically welding it to the adjacent thermoplastic layer of the packing laminate. For this process, the packing laminate and spout are pressed between an ultrasonic sonotrode and an anvil. The ultrasound heats the area in such a way that the flange and / or the adjacent layer of the packing laminate melt or at least softens. The pressure applied to the packing laminate and spout welds them together. However, this process often damages adjacent grooves. This can lead to cracking, leakage, and / or delamination of the packing laminate.

[0011] Similar problems can arise when sealing other packaging components to laminates, such as lids, cutlery, straws, giveaways, and the like. Corresponding problems can also occur when sealing components to other workpieces. These workpieces are preferably flat, at least in some areas, and may be laminated. It is advantageous if at least the surface is partially made of a thermoplastic material. Furthermore, these problems are particularly likely to occur if there is a discontinuity in the workpiece near the sealing point that impedes the unimpeded transmission of vibrations and / or heat.

[0012] Therefore, the present invention is based on the objective of designing and further developing the sealing device and the method of the type mentioned at the outset and explained in more detail above in such a way that damage and leaks of workpieces such as packing laminates, for example in the area of ​​groove lines, can be avoided by sealing equipment elements such as spouts to the workpieces or the packing laminates using ultrasound.

[0013] This problem is solved in a sealing device according to the preamble of claim 1 in that at least one pair of mutually corresponding clamping means, vibrationally decoupled from the sealing surface, is provided on opposite sides of the sealing gap for clamping the workpiece in the closed position, and that the at least one pair of clamping means are provided outside the sealing surface in a direction along the sealing gap, viewed with respect to the equipment element, in particular the spout.

[0014] The aforementioned problem is further solved according to claim 9 by a method for sealing equipment elements to workpieces, in particular in the form of a composite laminate, using ultrasound, preferably according to one of claims 1 to 8, in which the fitting element and the workpiece are each at least partially inserted into a sealing gap between a sonotrode and an anvil and pressed there between the sonotrode and the anvil, in which the pressed workpiece is clamped between at least one pair of corresponding clamping means from opposite sides of the sealing gap with respect to the fitting element outside the sealing surface, and in which, with the workpiece clamped, a sealing surface of the sonotrode, vibrationally decoupled from the at least one pair of clamping means, transmits ultrasound to the pressed fitting element and / or the pressed workpiece, thereby sealing the fitting element and the workpiece together.

[0015] According to the invention, not only are the workpiece, particularly in the form of a packing laminate, and the fitting element, particularly in the form of a spout, pressed between the sonotrode and the anvil to seal the fitting element to the workpiece, but the workpiece is also clamped between clamping means arranged on opposite sides of the sealing gap and thus on opposite sides of the workpiece held in the sealing gap. With the sonotrode and the anvil in the closed position, the clamping means can also be brought together to clamp the workpiece while the workpiece is being sealed to the fitting element. The clamping means are vibrationally decoupled from the sonotrode, so that, unlike via the sealing surface of the sonotrode, no significant amount of ultrasound is transmitted to the workpiece via the clamping means.

[0016] Furthermore, the clamping means are positioned outside the area to be sealed with respect to the component. This does not necessarily mean that the clamping means clamp the workpiece outside the flange of the component. It is also possible that the clamping means clamp the workpiece together with the flange of the component, outside the area to be welded or at least outside the contact surface between the workpiece and / or component on the one hand and the sealing surface of the sonotrode on the other. "Outside the sealing surface" means that the clamping means, with its clamping surface in contact with the workpiece, is not located on the side of the sealing surface facing a central area of ​​the component, but rather on the opposite side of the sealing surface.

[0017] This is achieved by first inserting the fitting element and the workpiece, at least partially, into a sealing gap between a sonotrode and an anvil, and then pressing them together. During the ultrasonic sealing of the workpiece and fitting element, the pressed workpiece is clamped between at least one pair of corresponding clamping elements on opposite sides of the sealing gap, specifically at a point outside the sealing surface of the sonotrode, relative to the fitting element. The sonotrode, which is vibrationally decoupled from the clamping elements, can then seal the workpiece, pressed between the sonotrode and the anvil, with the fitting 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.

[0018] The ultrasound ultimately delivers the energy required for sealing locally into the workpiece and / or the component. This energy is not only available in the area of ​​the seal but also radiates into other areas of the workpiece, even though the energy density within the workpiece decreases with increasing distance from the sealing surface of the sonotrode due to dissipation. However, the conduction of this energy within the workpiece is specifically terminated or at least significantly attenuated by clamping the workpiece. The energy cannot pass through the clamping area, or at least not easily.

[0019] The energy propagates through the workpiece primarily via heat conduction and the transmission of ultrasonic vibrations. In the clamping area, the transmission of ultrasonic vibrations is impeded because the clamped area cannot vibrate, or can only vibrate to a limited extent, due to the clamping action. The clamped area of ​​the workpiece thus acts as an obstacle to its vibration. Furthermore, the clamping elements absorb a significant portion of the heat conducted by the workpiece. Therefore, only a considerably smaller portion of the heat is conducted through the clamped area. Heat conduction is not blocked by the clamping itself; heat is still conducted through the clamped area. However, a significant portion of the heat conducted into the clamped area is drawn away from the workpiece through contact with the clamping elements.

[0020] Clamping the workpiece prevents, for example, such a high energy density from being transmitted to an adjacent groove line. The groove line also presents an obstacle to the propagation of ultrasonic vibrations within the workpiece, as the workpiece is more compact and rigid in the groove line area. Consequently, the workpiece conducts vibrations significantly less effectively in the groove line area than in the adjacent area. Vibrations reaching the groove line would therefore be either partially absorbed or partially reflected, leading directly to mechanical stress on the groove line and indirectly to heat generation at the groove line. This heat generation is further amplified by additional heat that is transported to the groove line via thermal conduction.All of these factors, individually or combined, can lead to damage to the groove line, which could result in leaks, cracking, and delamination of the workpiece if the clamping devices are not used in the manner described.

[0021] The processes previously described for a groove line can also occur at other discontinuities in a workpiece. Such discontinuities can be kinks, beads, tapers, openings, bores, joints, and the like. These elements can also impede the unimpeded propagation of ultrasonic vibrations and / or temperature within the workpiece. The workpiece can also be a composite laminate, if required. According to the invention, undesired delamination, i.e., the separation of individual layers of the laminate, can potentially be prevented in these workpieces.

[0022] In general, a clamping force of at least one pair of corresponding clamping elements has proven effective, which can range between 10 N and 150 N for typical applications. However, clamping forces between 25 N and 100 N or between 45 N and 70 N are particularly preferred.

[0023] For the sake of clarity and to avoid unnecessary repetition, the sealing device and the method are described together below, without differentiating between them in detail. However, the context will make it clear to a person skilled in the art which features are particularly preferred for the sealing device and the method.

[0024] In a first particularly preferred embodiment of the sealing device, the fitting element is designed as a spout and / or the workpiece as a packaging laminate, especially in the form of a cardboard / plastic composite laminate. In these cases, the advantages of the sealing device are particularly well utilized, as the workpiece could otherwise be especially susceptible to damage. A spout can also be used without a packaging laminate and vice versa. The advantages are particularly evident when a workpiece in the form of a cardboard / plastic composite laminate is used, as these are especially prone to delamination. Furthermore, such workpieces are often first joined with scoring lines and then with a fitting element to produce a cardboard composite package. Therefore, attaching the fitting element can negatively affect the scoring lines.Corresponding workpieces, in particular cardboard / plastic composite laminates, have a cardboard layer that serves as a structural support layer, providing the packaging with its basic stability and thus its fundamental structure. In addition, outer thermoplastic layers, such as polyethylene (PE), are preferably provided to seal the workpieces and protect the cardboard from moisture. Further layers, such as an aluminum layer, may also be included to prevent the diffusion of oxygen and other gases through the workpiece. The workpieces may also be printed with a design or similar on at least one side.

[0025] Alternatively or additionally, at least one pair of clamping elements can be provided, with respect to the sealing gap, at least substantially circumferentially around the sealing surface. In this way, the sealing energy introduced by the sealing surface of the sonotrode in the area of ​​the fitting element cannot propagate outwards, or not to a significant extent, in any direction. For the sake of simplicity and to avoid stress concentrations in the workpiece, it may also be advantageous if the at least one pair of clamping elements is provided at least substantially circularly around the sealing surface.

[0026] For example, at least two pairs of corresponding clamping elements can be provided on opposite sides of the sealing gap to clamp the workpiece in the closed position. This is advantageous if scoring lines only extend in certain directions adjacent to the sealing element. The propagation of the energy introduced during sealing must be limited only in these directions. The same applies if the workpiece has a fibrous layer, particularly a layer of cardboard, with a preferred fiber direction, which can also be referred to as the main fiber direction. In this case, the vibrations introduced into the workpiece are preferentially conducted in the main fiber direction. Thus, the propagation of the energy introduced during sealing only needs to be limited in this main fiber direction, if necessary on both sides radiating from the central area of ​​the sealing element.In this process, at least one additional pair of clamping elements is vibration-isolated from the sealing surface. This is to prevent any significant additional vibrations from being transmitted to the workpiece via the clamping elements. Furthermore, it is particularly advantageous if the at least two pairs of clamping elements, relative to the fitting element and viewed in one direction along the sealing gap, are positioned on opposite sides outside the sealing surface. This prevents excessive propagation of the sealing energy into the workpiece in the opposite direction.

[0027] If at least one clamping element of the at least one pair of clamping elements has an elastic section, further vibration decoupling from the sonotrode can be achieved. The vibrations from the sonotrode are then absorbed, at least to a significant extent, by the elastic material and thus removed from the system. Alternatively or additionally, this can achieve a more reliable clamping of the workpiece, if required. The elastic section of the clamping element can then help to compensate for unevenness in the workpiece in the clamping area. This allows for uniform and sufficient clamping of the workpiece. It is particularly simple and practical if the elastic section provides the clamping surface of the at least one clamping element for clamping the workpiece. Alternatively, the clamping surface should preferably be connected to other sections of the clamping element exclusively via the elastic section.The elastic section of the clamping device allows at least some of the vibrational energy to be absorbed from the workpiece. The workpiece vibrations cause the elastic section to vibrate, which, due to internal friction, converts these vibrations into heat. This heat can then be dissipated to the surroundings or other sections of the clamping device. Ideally, the elastic section should be made of a material with a low modulus of elasticity. The material's modulus of elasticity should preferably be less than 5.0 N / mm², preferably less than 2.5 N / mm², and particularly less than 1.0 N / mm². Alternatively, the elastic section can have a hardness between 20 and 100 Shore A, particularly between 40 and 80 Shore A. Suitable vibration damping characteristics have been achieved at these hardness levels.

[0028] For the sake of simplicity, at least one clamping element associated with the anvil, of the at least one pair of clamping elements, can be designed as part of the anvil. This is particularly the case if the corresponding clamping element has an elastic section. In this case, additional vibration decoupling can be achieved. However, vibrations are generally transmitted to the anvil via the sealing element and / or the workpiece during the sealing process itself. Therefore, additional vibration decoupling of the at least one clamping element associated with the anvil can usually be achieved if this clamping element is spaced at least substantially parallel to the sealing gap of the anvil in one direction. Consequently, no vibrations can be transmitted across this distance, especially if there is an air gap or similar between the anvil and the clamping element.Regardless, it can also be advantageous here if the clamping device has an elastic section. This allows for vibration decoupling, at least with respect to the workpiece. Simultaneously, this vibration decoupling also leads to welcome vibration damping in the clamping area of ​​the workpiece.

[0029] The most comprehensive possible vibration decoupling can be particularly important with regard to the sonotrode. Therefore, it may be advantageous if at least one clamping element of the at least one pair of clamping elements associated with the sonotrode is positioned at least substantially parallel to the sealing gap in one direction. This distance prevents the transmission of vibrations, especially if there is an air gap or similar between the anvil and the clamping element.

[0030] Alternatively or additionally, a vibration damper in the form of a solid component with increased inertia can be used to dampen vibrations. This is possible by attaching at least one clamping element of the at least one pair of clamping elements to a vibration damper with a mass between 50 g and 400 g, preferably between 80 g and 300 g, and particularly between 125 g and 225 g. This can be at least one clamping element associated with the anvil and / or at least one clamping element associated with the sonotrode. The latter can be particularly advantageous, since the ultrasonic waves are generated by the sonotrode and also transmitted from the sonotrode to the workpiece and / or the equipment element. To ensure that the vibrations are damped primarily through inertia via the vibration damper, it may be beneficial for the vibration damper to be made of a material with a modulus of elasticity of at least 50.000 N / mm²< , preferably at least 100,000 N / mm²< , in particular at least 150,000 N / mm²< , is formed.

[0031] Regardless, for uniform vibration damping, it may be advantageous to provide at least one clamping element of the at least one pair of clamping elements on a vibration damper that is designed to encircle the sonotrode and / or the sealing surface in a substantially ring-shaped manner. Here, too, the at least one clamping element can be assigned to the anvil and / or the sonotrode. Since the ultrasonic waves, as described, are generated by the sonotrode and transmitted from the sealing surface of the sonotrode to the workpiece and / or the fitting element, it is particularly advantageous here as well if the corresponding clamping element is assigned to the sonotrode.

[0032] To achieve optimal clamping of the workpiece, even considering possible tolerances or other deviations, it is advantageous to provide at least one clamping element that is adjustable, preferably pivotable or tiltable. This is particularly beneficial if at least one clamping element of the at least one pair of clamping elements is pivotable about at least one pivot axis, aligned at least substantially parallel to the sealing gap, relative to the sonotrode and / or the anvil. This ensures good contact between the clamping element and the workpiece. Furthermore, this can be achieved with exceptional reliability if the clamping element is freely pivotable about the pivot axis. Since the sonotrode generates the vibrations, the corresponding clamping element can preferably be located near the sonotrode.Alternatively or additionally, with regard to vibration damping, it is particularly preferred if the clamping means together with the vibration damper is provided to be pivotable about at least one pivot axis.

[0033] To ensure reliable and effective clamping, at least one clamping element of the at least one pair of clamping elements can be spring-loaded, at least substantially, in the direction of the sealing gap. This allows the clamping force to be predetermined or adjusted to a certain extent. For the sake of simplicity, it is advisable to provide the clamping element spring-loaded together with the vibration damper. In this case, too, particularly good results can be achieved if the clamping element is associated with the sonotrode causing the vibrations.

[0034] In a first particularly preferred embodiment of the method, a spout is used as the component and / or a packaging laminate, especially in the form of a cardboard / plastic composite laminate, is used as the workpiece. In these cases, the advantages of the method are particularly well utilized, as the workpiece could otherwise be especially susceptible to damage. A spout can also be used without a packaging laminate and vice versa. The advantages are particularly evident when a workpiece in the form of a cardboard / plastic composite laminate is used, as these are especially prone to delamination. Furthermore, such workpieces are often first joined with scoring lines and then with a component to produce a cardboard composite package. Therefore, attaching the component can adversely affect the scoring lines.Corresponding workpieces, in particular cardboard / plastic composite laminates, have a cardboard layer that serves as a structural support layer, providing the packaging with its basic stability and thus its fundamental structure. In addition, outer thermoplastic layers, such as polyethylene (PE), are preferably provided to seal the workpieces and protect the cardboard from moisture. Further layers, such as an aluminum layer, may also be included to prevent the diffusion of oxygen and other gases through the workpiece. The workpieces may also be printed with a design or similar on at least one side.

[0035] Alternatively or additionally, the workpiece can be clamped by the clamping elements of at least one pair in a longitudinal direction of the clamping elements at least predominantly transverse to a main fiber direction of the workpiece. This reliably interrupts or at least significantly reduces the transmission of vibrations and heat, which occurs predominantly in the direction of the fibers, through the clamping elements and the corresponding clamping of the workpiece. This is particularly true if the longitudinal direction of the clamping elements is oriented at least substantially perpendicular to the main fiber direction of the workpiece, especially the cardboard. In many cases, not all fibers of a workpiece, especially of a cardboard layer of the workpiece, will be aligned parallel to each other.However, it will often still be the case that most and / or the longest fibers of the workpiece, especially of a cardboard layer of the workpiece, are at least approximately aligned parallel to each other. This direction is then considered the main fiber orientation.

[0036] Alternatively or additionally, it is advantageous if the workpiece is clamped between the fitting element and a groove line on the workpiece. This prevents the energy introduced into the workpiece as vibrations and heat during sealing from being conducted unhindered towards the groove line, potentially causing damage to the groove line and / or the workpiece. Clamping the workpiece with the clamping devices significantly restricts the conduction of this energy.

[0037] Since scoring lines are often arranged on opposite sides of the component, particularly when viewed along the main grain direction, it is advantageous to clamp the workpiece on opposite sides of the component, especially when viewed along the main grain direction. Clamping in other directions, such as perpendicular to the main grain direction, can be omitted to protect the workpiece. This can be beneficial if scoring lines are only provided at a certain distance in these directions, or if the energy transmission perpendicular to the main grain direction is so low that the energy transmission can be accepted without fear of damaging the scoring lines there.

[0038] The propagation of energy introduced into the workpiece during sealing can be limited particularly easily and reliably if the workpiece is clamped at least substantially circumferentially by the clamping means. This limits propagation in all directions. This is achieved particularly easily and uniformly if the workpiece is clamped at least substantially circularly around the sonotrode and / or the sealing surface.

[0039] To reduce vibrations overall and thus eliminate them from the system, at least one clamping element of the at least one pair of clamping elements can have at least one elastic section. During sealing, this section can then at least partially absorb the ultrasonic vibrations. However, this requires appropriate contact with the workpiece to transmit the vibrations to the elastic section. This is particularly easy to achieve if the elastic section provides a clamping surface for a clamping element. Alternatively, the clamping surface should preferably be connected to other sections of the clamping element exclusively via the elastic section. The vibrations of the workpiece cause the elastic section to vibrate, and this vibration is converted into heat due to internal friction. The resulting heat can then be dissipated to the environment or to other sections of the clamping element.It is generally advantageous if the elastic section is made of a material with a low modulus of elasticity. The modulus of elasticity of the material should preferably be less than 5.0 N / mm², preferably less than 2.5 N / mm², and particularly less than 1.0 N / mm². Alternatively, the elastic section can have a hardness between 20 and 100 Shore A, particularly between 40 and 80 Shore A. Suitable vibration damping characteristics have been achieved at these hardness levels.

[0040] Alternatively or additionally to vibration absorption, vibration damping can also be provided. In absorption, the vibrations are converted into elastic deformation of the elastic section, and the corresponding energy is thus dissipated. In damping, on the other hand, the inertia of a sufficiently large vibration damper is used. This damper must also be brought into contact with the workpiece in such a way that the vibrations can be transmitted from the workpiece to the vibration damper. Methodically, the vibrations transmitted from the sonotrode to the at least one clamping element of the at least one pair of clamping elements can be damped by a vibration damper carrying the clamping element, with a mass between 50 g and 400 g, preferably between 80 g and 300 g, and particularly between 125 g and 225 g.This leads to sufficient energy dissipation within the system to protect the adjacent groove lines from this energy. To ensure that the vibrations are primarily damped by inertia via the vibration damper, it is advantageous for the vibration damper to be made of a material with a modulus of elasticity of at least 50,000 N / mm², preferably at least 100,000 N / mm², and particularly at least 150,000 N / mm².

[0041] Alternatively or additionally, it is also advantageous if the vibrations transmitted from the sonotrode to the at least one clamping element of the at least one pair of clamping elements are damped by a vibration damper that supports the clamping element and circulates around the sonotrode. This results in a compensation of vibrational energy when the vibrations introduced during sealing are transmitted differently in different directions. This compensation is achieved to a particularly high degree when the vibration damper is designed to circulate around the sonotrode, at least substantially in a ring shape.

[0042] To ensure sufficient contact between the clamping elements and the workpiece, it is advantageous to pivot at least one clamping element of the at least one pair of clamping elements about a pivot axis aligned at least substantially parallel to the sealing gap. Inaccuracies in the process or with regard to the workpiece can thus be compensated for, which can contribute to uniform clamping as intended. For the sake of simplicity and better vibration damping, the at least one clamping element can be pivoted together with the vibration damper about the pivot axis aligned at least substantially parallel to the sealing gap.

[0043] The at least one clamping element of the at least one pair of clamping elements can clamp the workpiece at least partially with a clamping force generated at least partially by a restoring force of at least one spring element. This makes it easy to ensure, as needed, that the workpiece is clamped with a sufficient clamping force to impede the propagation of the energy introduced into the workpiece during sealing, while the clamping force is not so great as to damage the workpiece during clamping. It is advantageous if the at least one clamping element, together with the vibration damper, is subjected to a restoring force via the at least one spring element during clamping. This simultaneously ensures that the vibrations transmitted from the workpiece to the clamping element are reliably and effectively transferred to the vibration damper.

[0044] The invention will now be explained with reference to a drawing that illustrates only one embodiment. The drawing shows Fig. 1A - Legs of the sealing device according to the invention in the open position in perspective views, Fig. 2 the anvil of the sealing device made of Fig. 1 In a top view, Fig. 3, the sonotrode and a vibration damper of the sealing device are shown. Fig. 1 in a top view and Fig. 4A-C the sealing device made of Fig. 1 in the open position and the closed position during the method according to the invention.

[0045] In the Fig. 1A-B A sealing device 1 for sealing fittings 2 in the form of spouts to workpieces 3 in the form of a packaging laminate, in particular a cardboard / plastic composite laminate, is shown using ultrasound. The sealing device 1 provides a sealing gap 4 into which a part of the workpiece 3 and the fitting 2 can be inserted. A sonotrode 5 is provided on one side of the sealing gap 4, which can generate an ultrasonic vibration and transmit it to the workpiece 3 via the sealing surface 6 of the sonotrode 5. Opposite the sonotrode 5, an anvil 7 is arranged on the other side of the sealing gap 4, which can receive a flange 9 of the fitting 2 in a receptacle 8.The sonotrode 5 then presses the workpiece 3 against this flange 9 and in the meantime transmits the ultrasonic vibration to the workpiece 3 in order to seal the workpiece 3 at the corresponding point with the flange 9 of the equipment element 2.

[0046] Simultaneously, the clamping elements 10, 11 of two pairs of corresponding clamping elements 10, 11 clamp the workpiece 3 between them to prevent the vibrations introduced into the workpiece 3 during sealing and the heat induced in the workpiece 3 from being conducted almost unhindered through the workpiece 3 towards adjacent groove lines 12. The energy generated by the vibrations and heat of the workpiece 3 could otherwise damage the groove lines 12. For example, the workpiece 3 could crack, leak, and / or delaminate in the area of ​​the groove line 12.

[0047] In the area of ​​the clamped workpiece 3, heat and vibrations are transferred from the workpiece 3 to the corresponding clamping elements 10, 11 and therefore cannot be conducted further outwards from the workpiece 3 to this extent. The clamping elements 10, 11 are positioned opposite each other on both sides of the sealing gap 4 and are thus assigned either to the anvil 7 or the sonotrode 5. The clamping elements 11 assigned to the anvil 7 are made of an elastic material, though not necessarily silicone in this case. The elastic section 13 of the clamping elements 11 also forms the clamping surfaces 14 of the corresponding clamping elements 11. In this way, it is prevented that the vibrations are transmitted unhindered from the workpiece 3 to the anvil 7 or from the anvil 7 to the workpiece 3 via the clamping elements 11.The vibrations are partially absorbed by the clamping means 11 and lead to an elastic deformation there, through which the vibrational energy is absorbed in the clamping means 11.

[0048] The vibrations transmitted to the anvil 7 by the sealing element 2 during the sealing process cannot be transmitted to the workpiece 3 by the clamping means 11, or only to a limited extent. These vibrations also cause elastic deformation of the clamping means 11, which are made of an elastic material, and thus lead to the absorption of the corresponding energy, which can therefore no longer be transmitted from the anvil 7 to the workpiece 3 via the associated clamping means 11. Ultimately, the clamping means 11 associated with the anvil 7 provide vibration decoupling between the anvil 7 and the workpiece 3.

[0049] The clamping elements 10 associated with the sonotrode 5 are held by a vibration damper 15, which is spaced apart from the sonotrode 5 and thus vibrationally decoupled from both the sonotrode 5 and the sealing surface 6 of the sonotrode 5. The vibration damper 15 is itself freely pivotable on a pivot axis 16. The pivot axis 16 extends at least substantially parallel to the sealing gap 4. In this way, the clamping surfaces 14 of the clamping elements 10 are always aligned parallel to the workpiece 3 in order to clamp the workpiece 3 evenly over the clamping surfaces 14.

[0050] The pivot axis 16, and thus the vibration damper 15, is adjustable in one direction at least substantially perpendicular to the sealing gap 4 relative to the sonotrode 5 and the sealing surface 6 of the sonotrode 5. The vibration damper 15 is spring-loaded in the direction of the sealing gap 4. In other words, the vibration damper 15 can be spaced away from the sealing gap 4 against the restoring force of the spring elements 17. This limits the maximum clamping force between the pairs of corresponding clamping elements 10 and 11.

[0051] In the Fig. 2 The anvil 7 is shown in a top view as seen from the sealing gap 4. The anvil 7 has a receptacle 8 in which the flange 9 of the fitting element 2 can be received. When the fitting element 2 is sealed to the workpiece 3, the fitting element 2 is pressed by the sonotrode 5 over the workpiece 3 against the receptacle 8 of the anvil 7. An opening 18 is provided in the receptacle 8 of the anvil 7 through which a vacuum can be drawn in the receptacle 8 in order to securely hold the fitting element 2 in the receptacle 8 of the anvil 7. The clamping means 11 associated with the anvil 7 are arranged on opposite sides of the receptacle 8 and spaced apart from it. The clamping means 11 project slightly into the sealing gap 4 opposite the receptacle 8.Since the clamping elements 11 are made of an elastic material, they can be compressed slightly, to the point that they no longer protrude, or no longer protrude, from the receptacle 8. The clamping surfaces 14 of the clamping elements 11 can then be aligned flush with the receptacle 8 of the anvil 7 and / or with the flange 9 of the fitting element 2.

[0052] In the Fig. 3 The sonotrode 5, together with the vibration damper 15, is shown in a top view from the sealing gap 4. The sonotrode 5 has a central receptacle 19 for receiving the part of the fitting element 2 that projects outwards beyond the workpiece 3. This part of the fitting element 2 preferably comprises a screw cap 20. The sealing surface 6 of the sonotrode 5 is provided around this receptacle 19. The sealing surface 6 of the illustrated and thus preferred sonotrode 5 is circular. With the sealing surface 6, the sonotrode 5 presses against the workpiece 3, which is arranged above the also circularly shaped flange 9, in order to subject the connection to ultrasound and thus seal, i.e., weld it.A vibration damper 15 is provided around and spaced apart from the sonotrode 5 and the sealing surface 6. The vibration damper 15 carries two clamping elements 10, which correspond to the clamping elements 11 associated with the anvil 7. The clamping elements 10 associated with the sonotrode 5 are solid and are held by the more solid vibration damper 15. In the illustrated and thus preferred sealing device 1, the clamping elements 10 associated with the sonotrode 5 and the vibration damper 15 are made of metal, in particular steel.

[0053] The vibration damper 15 is arranged around the perimeter of the sonotrode 5 and the sealing surface 6 and is held in corresponding recesses of the sealing device 1 by two pins 21. The pins 21 define a pivot axis 16 about which the vibration damper 15 can be pivoted relative to the recesses 22 at least substantially parallel to the sealing gap 4. The recesses 22 can be adjusted slightly forwards and backwards relative to the sealing surface 6 in the direction of the sealing gap 4. Since the recesses 22 and / or the vibration damper 15 are spring-loaded via spring means 17, the vibration damper 15 is adjusted relative to the sonotrode 5 and away from the anvil 7 against the restoring force of the spring means 17.

[0054] In the Fig. 4A-C Different positions of the sealing device 1 during the sealing process are shown. Fig. 4A The sealing device 1, with the sonotrode 5 and the anvil 7, is shown in an open position in which a fitting element 2 can be inserted into the sealing gap 4 and, with the flange 9, inserted into the corresponding receptacle 8. The fitting element 2 is held in the position shown by applying a vacuum to the receptacle 8.

[0055] Then, as described in the Fig. 4B As shown, workpiece 3 is inserted into the sealing gap 4 such that the fitting element 2 protrudes through a corresponding hole 23 in workpiece 3. Alternatively, workpiece 3 could first be positioned accordingly. Then, fitting element 2 could be inserted into the sealing gap 4 and pushed through the corresponding hole 23 in workpiece 3. Workpiece 3 then covers the flange 9 of fitting element 2 completely around the hole 23 in workpiece 3.

[0056] Now the sonotrode 5 and / or the anvil 7 can be adjusted relative to each other into the closed position, as shown in the Fig. 4CAs shown in the figure. In the closed position, the sonotrode 5 is activated and transmits the ultrasound to the workpiece 3, which, together with the flange 9 of the fitting element 2, heats up in the area of ​​the flange 9, thus forming a material bond between the workpiece 3 and the fitting element 2. Simultaneously, the workpiece 3 is clamped between the clamping elements 10, 11, so that the ultrasound and the heat in the workpiece 3, relative to the fitting element 2, can only be transmitted to the outside to a limited extent beyond the clamping of the workpiece 3 between the clamping elements 10, 11. The groove lines 12 of the workpiece 3 in this area are therefore not excessively affected by the sealing of the workpiece 3 and the fitting element 2. After sealing, the sonotrode 5 and the anvil 7 are returned to the open position relative to each other.The workpiece 3 with the attached fitting element 2 can then be removed from the sealing gap 4. The cycle is complete and can now be repeated to attach another workpiece 3 with a fitting element 2. Reference symbol list

[0057] 1 Sealing device 2 Fitting element (spout) 3 Workpiece (packing laminate) 4 Sealing gap 5 Sonotrode 6 Sealing surface 7 Anvil 8 Receptacle 9 Flange 10 Clamping element (sonotrode) 11 Clamping element (anvil) 12 Grooving lines 13 Elastic section 14 Clamping surface 15 Vibration dampers 16 Swivel axis 17 Spring element 18 Opening 19 Receptacle 20 Screw cap 21 Pin 22 Recess 23 Hole

Claims

1. Sealing device (1) for sealing fitting element (2) to workpieces (3), in particular in the form of a composite laminate, by means of ultrasound, with a sonotrode (5) for generating ultrasound, with a sealing surface (6) for transmitting the ultrasound to the fitting element (2) and / or the workpiece (3), with an anvil (7) opposite the sonotrode (5) and with an adjustment device for adjusting the sonotrode (5) and the anvil (7) relative to each other from an open position for at least partially introducing 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 back, characterized in that at least one pair of clamping means (10, 11) corresponding to one another which are vibrationally decoupled from the sealing surface (6) and are provided on opposite sides of the sealing gap (4) for clamping the workpiece (3) in the closed position, and that 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 a direction along the sealing gap (4).

2. Sealing device according to claim 1, characterized in that the equipment element (2) is configured 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 that the at least one pair of clamping means (10, 11) is provided, relative to the sealing gap (4), at least substantially circumferentially, at least substantially circularly, around the sealing surface (6).

3. Sealing device according to claim 1 or 2, characterized in that at least two pairs of clamping means (10, 11) corresponding to one another that are vibration-decoupled from the sealing surface (6) are provided on opposite sides of the sealing gap (4) for clamping the workpiece (3) in the closed position, and that the at least two pairs of clamping means (10, 11) are provided on opposite sides outside the sealing surface (6) relative to the equipment element (2) and viewed in a direction along the sealing gap (4).

4. Sealing device according to one of claims 1 to 3, characterized in that at least a clamping means (10, 11) of the at least one pair of clamping means (10, 11) has an elastic section (13) for vibration decoupling from the sonotrode (5) and that, preferably, the elastic section (13) provides the clamping surface (14) of the clamping means (10, 11) for clamping the workpiece (3)5. Sealing device according to one of claims 1 to 4, characterized in that at least one clamping means (11) of the at least one pair of clamping means (10, 11), preferably comprising the elastic section (13), associated with the anvil (7), is formed as part of the anvil (7) or spaced apart from the anvil (7) in a direction at least substantially parallel to the sealing gap (4).

6. Sealing device according to one of claims 1 to 5, characterized in that at least one clamping means (10) of the at least one pair of clamping means (10, 11) associated with the sonotrode (5) is spaced apart from the sonotrode (5) in a direction at least substantially parallel to the sealing plane (4).

7. Sealing device according to one of claims 1 to 6, characterized in that at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11), in particular associated with the sonotrode (5), is fixed to a vibration damper (15) with a mass between 50 g and 400 g, preferably between 80 g and 300 g, in particular between 125 g and 225 g, and / or that at least one clamping means (10, 11), in particular associated with the sonotrode (5), clamping means (10, 11) of the at least one pair of clamping means (10, 11) is provided on a vibration damper (15) which is provided at least substantially annularly around the sonotrode (5).

8. Sealing device according to one of claims 1 to 7, characterized in that at least one clamping means (10, 11), in particular assigned to the sonotrode (5), of the at least one pair of clamping means (10, 11), in particular together with the vibration damper (15), is provided pivotably, about at least one pivot axis (16) at least substantially parallel to the sealing gap (4) relative to the sonotrode (5) and / or the anvil (7), in particular freely pivotable, and / or that at least one clamping means (10, 11), in particular associated to the sonotrode (5), of the at least one pair of clamping means (10, 11), in particular together with the vibration damper (15), is spring-loaded at least substantially in the direction of the sealing gap (4).

9. Method for sealing fitting elements (2) to workpieces (3), in particular in the form of a composite laminate, by means of ultrasound, preferably according to one of claims 1 to 8, - in which the fitting element (2) and the workpiece (3) are respectively at least partially introduced into a sealing gap (4) between a sonotrode (5) and an anvil (7) and pressed there between the sonotrode (5) and the anvil (7), characterized in that - the pressed workpiece (3) is clamped between at least one pair of corresponding clamping means (10, 11) from opposite sides of the sealing gap (4) relative to the equipment element (2) outside the sealing surface (6), and - that, with the workpiece (3) clamped, a sealing surface (6) of the sonotrode (5), which is vibration-decoupled relative to the at least one pair of clamping means (10, 11), transmits ultrasound to the pressed fitting element (2) and / or the pressed workpiece (3) and thereby seals the fitting element (2) and the workpiece (3) to one another.

10. Method according to claim 9, - in which the fitting elements (2) are spouts and / or the workpieces (3) are packaging laminates, in particular in the form of a cardboard / plastic composite laminate, and / or - in which 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 substantially perpendicularly, to a main fiber direction of the workpiece (3) and / or - in which the workpiece (3) is clamped between the equipment element (2) and a creasing line (12) of the workpiece (3).

11. Method according to claim 9 or 10, - in which the workpiece (3) is clamped by the clamping means (10, 11) on opposite sides of the fitting element (2) and - wherein, preferably, the workpiece (3) is clamped by the clamping means (10, 11) at least substantially circumferentially, in particular at least substantially circularly, around the fitting element (2).

12. Method according to one of claims 9 to 11, - wherein at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11) absorbs the vibrations in an elastic section (13), in particular providing a clamping surface (14), during sealing.

13. Method according to one of claims 9 to 12, in which the vibrations transmitted from the sonotrode (5) to the at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11) are damped by a vibration damper (15) carrying the clamping means (10, 11) and having a mass of between 50 g and 400 g, preferably between 80 g and 300 g, in particular between 125 g and 225 g, and / or - in which the vibrations transmitted from the sonotrode (5) to the at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11) are damped by a vibration damper (15) carrying the clamping means (10) and extending at least substantially annularly around the sonotrode (5).

14. Method according to one of claims 9 to 13, - in which at least one clamping means (10, 11) of the at least one pair of clamping means (10, 11), in particular together with the vibration damper (15), is pivoted for clamping about a pivot axis (16) aligned at least substantially parallel to the sealing gap (4).

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