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    • 专利摘要:
    The invention relates to a honeycomb sandwich structure (170) for use in a sound-damping panel (200) comprising a core layer (130) provided with perforations (120) and a cover layer (160) applied thereto together with it thermoformed. The perforations (120) representing a certain design or geometry improve the acoustic sound-damping properties of the structure and therefore of the panel (200). The cover layer (160) is, for example, a textile layer with needle felt. The invention also relates to a method for manufacturing such a sandwich structure (170) for a sound-damping panel (200) which includes inter alia the processes of perforating and thermoforming (510).
    公开号:BE1026313B1
    申请号:E20185650
    申请日:2018-09-21
    公开日:2019-12-23
    发明作者:Hans Soenen；Martial Geudin
    申请人:Houtbuigerij G Desmet Nv；Dejager Invest Group Nv；
    IPC主号:
    专利说明:

    SOUND-ABSORBABLE PANEL AND METHOD FOR MANUFACTURING SUCH SOUND-Absorbing PANEL
    Technical field
    The invention relates to a sound-absorbing or sound-damping panel comprising a honeycomb sandwich structure, provided with perforations and a finishing covering layer applied thereto with which it is thermoformed together. The perforations that represent a certain design or geometry reinforce the acoustic sound-damping properties of the panel. The finishing cover layer is, for example, a (needle felt) textile layer. The invention also relates to a method for manufacturing such a sound-absorbing or sound-damping panel, which comprises inter alia the processes of perforating and thermoforming.
    BACKGROUND OF THE INVENTION
    Acoustic panels comprising a perforated honeycomb base structure exist according to the state of the art. Multiple types of perforations can be devised to provide holes within one or both sheets of the sandwich base. However, there is room for improvement of the panel in the manner in which perforations can be designed, as well as in the manner of manufacture thereof. In addition, in the case of using a paper or cardboard honeycomb sandwich base, for example, the current existing perforation techniques are rather poor and limited in performance and capabilities. Alternatively, the production of sandwich panels with pre-perforated paper creates difficulties due to wetting, weakening and tensile forces on the material, making such production almost impossible.
    While providing coatings via thermoforming in acoustic panels is also known, such processing lacks flexibility and creativity in design or geometry, and therefore also fails in the performance characteristics of the panel.
    Object of the invention
    -2 BE2018 / 5650
    The object of the invention is to provide a sound-absorbing panel with improved properties, at least in terms of its acoustic properties, as well as to provide a method for manufacturing such a sound-absorbing panel.
    Summary of the invention
    According to a first aspect of the invention, a sandwich element is provided that is suitable for use in a sound-damping panel. The sandwich element is a combined element and comprises a cellular element or core or base and a first sheet or sheet or plate applied to both sides or surfaces of the cellular element. The first sheet or sheet or plate comprises perforations on at least one side of the cellular element. Perforations are, for example, slit-shaped. A portion of the material of the first sheet that includes perforations remains attached to the first sheet. The cellular element provided with the first sheet on each side thereof forms a plate-like element. As an example of such a non-perforated plate-shaped element, a hexagon cardboard plate that is stronger than any individual component can be used due to its internal structure and bonded coatings. Such a hexagonal cardboard plate with a cellular core is characterized by hexagonal or honeycomb cells. In order to increase the acoustic value of the cardboard plate, small openings are provided that lead to the hollow chambers of the hexagonal structure, through which sound can enter, be absorbed and can be muted. According to an embodiment, a portion of the material of the first sheet that includes perforations and remains attached to the first sheet is folded toward the honeycomb cells of the cellular element. Such a folded structure can be seen, for example, as small flaps that are bent towards the inside of the cellular core and can therefore further improve the acoustic properties of the cardboard plate. Cellular core plates with a certain thickness and structure are used, for example, and fully or partially converted into perforated versions by mechanical manipulation. In other words, the perforation of the plate-like element can be one-sided or two-sided. According to one embodiment, the sandwich element has a geometric shape such as, for example, a rectangular or polygon shape, or it is either non-angular and represents an oval or circular shape. According to an embodiment, part of the
    - 3 BE2018 / 5650 cardboard sandwich elements are cut out. The cutting out of such a part takes place through the entire sandwich structure, i.e. by a cellular element (or core) and a first sheet arranged thereon on both sides. By way of example, another geometric shape (e.g., rectangular, polygonal, oval, or circular but not necessarily the same type of shape as the sandwich element itself) can be cut from the sandwich element, which is substantially larger than the perforations. In comparison, there is on average one perforation per honeycomb or hexagonal cell, while a portion that is cut out comprises, for example, a few or a few dozen honeycomb cells. According to one embodiment, a portion of the cardboard sandwich element is cut after the first sheet has been applied to the cellular core. In another embodiment, a portion of the cardboard sandwich element is cut out before the first sheet is applied to the cellular core. In one embodiment even, such a part that is cut before or after the first sheet is applied to the cellular core is not cut through the entire structure of the core (whether or not provided with the first sheet), and therefore a part remains of the material with a different thickness than the other non-cut part. In one embodiment, several parts could be cut out of the sandwich element (with or without the first sheet applied to it) and wherein these multiple parts were cut entirely or partially through the entire core structure (with or without the first sheet applied to it). Because cut-out portions can only be partially cut-out, there could be differences in cutting depth, and therefore different thicknesses could result in the cut-out sandwich element. According to an embodiment, the space where a portion of the cardboard material is cut out, e.g. partially through the core with first sheet applied thereto, can be used to embed or integrate a system or device with an additional application or features other than the acoustic properties in particular. An example of such a system or device could be, for example, a lighting device, a magnetic system or a communication or other electronic element. The sandwich element comprising the cellular element and the first sheet as described above can be interpreted as a semi-finished product to which an additional second sheet can be applied. Moreover, according to an embodiment, the second sheet is arranged in particular on the first sheet of the sandwich element. Such a second sheet can be seen as a cover layer and can therefore be a finishing layer, although this is not necessarily the case. Optionally, a coating, paint layer or decorative layer could generally be applied to the second sheet. According to an embodiment, the second sheet is
    -4 BE2018 / 5650 suitable for thermoforming and is for example made of needle felt textile. In addition, the second sheet can include extensions, which can be seen as the extensions over the dimensions of the cellular element that are provided with the first sheet on both sides. The extensions over the dimensions of the cellular element provided with the first sheet are also recognizable over the space of the one or more cut-out geometric parts as defined above. In other words, the extensions are extended over the sandwich structure with cut-out shapes and cover the open space of the cut-out parts. The cellular element and / or the first sheet and / or the second sheet can be connected to an adhesive such as glue, and / or the second sheet can be thermoformed on the first sheet. The extensions as a part of the second sheet can also be connected with an adhesive such as glue and / or can be thermoformed as bonded extensions. Moreover, according to an embodiment, such a connection or thermoforming takes place between extensions of or on both sides of the first sheet and the cellular element, respectively, which match one another.
    According to the second aspect of the invention, a sound-damping panel is provided which comprises one or more of the sandwich elements in accordance with the first aspect of the invention. In one embodiment, two or more separate sandwich elements are placed next to each other, at a distance from each other, as a core with a first blade arranged thereon and perforated on at least one side. For example, in the case of identical, regular or uniformly shaped sandwich elements, these can then be aligned and assembled. For this composition, the second sheet is of such a size that it can cover all sandwich elements together, in addition to displaying extensions where the outer edges of the composite acoustic panel are generated.
    According to the third aspect of the invention, a method is provided for manufacturing a sandwich element in accordance with the first aspect of the invention. The method comprises the steps of: (i) providing a cellular element, (ii) providing a first sheet on each side of the cellular element and then (iii) perforating the first sheet at least on one side of the cellular element. According to an embodiment, the method further comprises the step of (iv) providing a second sheet on the first sheet. A method of manufacturing a sound-damping panel comprising one or more sandwich elements in accordance with the first aspect of the invention makes
    BE2018 / 5650 also forms part of the invention. The provision of the first sheet on both sides of the cellular element can be performed by using an adhesive such as glue, and / or applying the second sheet to the first sheet can be done by means of an adhesive such as glue and / or thermoforming.
    According to a fourth aspect of the invention, a cutting drum is provided, suitable for use in a method of manufacturing a sandwich element in accordance with the third aspect of the invention. The cutting drum, for example cylindrically shaped, comprises one or more knives arranged on a roll and is arranged such that it is used for perforating the first sheet on at least one side of the cellular element, wherein a part of the perforated material first sheet remains attached or attached to the first sheet. According to an embodiment, a number of blades are mounted on the roll, both radially and in parallel. In order to realize the perforation of the cellular element provided on either side, or to refer otherwise to plate-like elements as mentioned earlier, such as for instance rigid honeycomb cardboard plates, one or more knife-provided rollers are used between which the plates are pulled.
    According to a fifth aspect of the invention, a perforating machine is provided, suitable for use in a method for manufacturing a sandwich element that is suitable for use in a sound-damping panel. The perforating machine is adapted to manufacture a sandwich element according to the first aspect of the invention. The perforating machine is adapted to receive a cellular element which is provided with a first sheet thereon, more particularly on either side of the cellular element, between at least one cutting drum according to the fourth aspect of the invention and a guiding carrier for transporting of the sandwich element. According to a special embodiment, the distance between the suspension or the position of the cutting drum on the one hand and the conductive carrier on the other can be adjusted. According to an embodiment, two cutting drums are provided with the perforating machine, for simultaneously perforating the first sheet on each side or both surfaces of the cellular element. With only one cutting drum that is part of the perforating machine, perforation on both sides can also be provided in a sequential manner.
    According to a sixth aspect of the invention there is provided an arrangement suitable for use in a method of manufacturing a sandwich element which
    -6 BE2018 / 5650 is suitable for use in a sound-damping panel. The arrangement is adapted to manufacture a sandwich element in accordance with the first aspect of the invention. More specifically, the arrangement is adapted to receive the cellular element with the first sheet disposed thereon, and wherein the first sheet is perforated on at least one side of the cellular element. The arrangement is also adapted to provide a second sheet on the first sheet. The arrangement comprises an oven for preheating the sandwich element, or a heated mold for directly performing the thermoforming process. In one embodiment, the arrangement next to the oven, and as part of indirect or 2-step thermoforming, includes components such as a printing form for applying mechanical pressure to at least the extensions of the second layer of the preheated sandwich element, or to the entire second sheet of the pre-heated sandwich element. According to an embodiment, the sandwich elements must be pre-cut and must be completely enclosed by the needle felt (fiber-containing fabric or textile sheet). In addition, the sandwich core material must be placed centrally in the mold or mold. When the mold or mold is closed, the clamping with pneumatic cylinders, controlled by a sensor, is withdrawn to prevent getting between the mold blocks.
    According to further aspects of the invention, there is also disclosed (i) a data processing system comprising means for performing the method of operating a perforating machine and the device according to respectively the fifth and sixth aspects of the invention, (ii) a computer program comprising software code which is adapted to perform the method of operating the perforating machine and the arrangement according to the fifth and sixth aspects of the invention respectively, and (iii) a computer-readable storage medium comprising the computer program as mentioned, in particular software code which is adapted to perform the method of operating the perforating machine and the arrangement according to the fifth and sixth aspects of the invention, respectively. The production methods are most likely automated and / or computer-controlled.
    With the invention a unique relationship is established between, for example, the movement in relation to speed and direction of rotation of the rollers of the cutting drum, the shape and diameter of the cutting blades or knives, the shape of the teeth, the adaptation to the material to be perforated , spreading and the diameter of the
    -7 BE2018 / 5650 perforation in relation to the internal structure of the material and the correlation between all components, resulting in the good acoustic properties of the material and therefore of the cellular sandwich plate structure, after perforation and this without loss of strength. In addition, the perforation of the plates also offers a new, controlled flexibility property, allowing controlled arches and sharp edges and allowing curved shapes to be made with different radii.
    Overview of the drawings
    Figure 1 shows an embodiment of a semi-finished step of a sound-absorbing panel, representing a honeycomb core with perforated sheet or plate according to the invention.
    Figure 2 shows an embodiment of a perforation manufacturing tool for perforating a sound-absorbing panel, in (a) perspective view, (b) side view, and (c) cross-sectional view in accordance with the invention.
    Figure 3 shows an embodiment of a cutting roller as part of the perforation manufacturing tool for perforating a sound-absorbing panel in accordance with the invention.
    Figure 4 shows another embodiment of a semi-finished step of a sound-absorbing panel, showing a perforated honeycomb sandwich structure provided with a needle felt cover layer according to the invention.
    Figure 5 shows an embodiment of thermoformed asymmetrically curled edges of a sound-absorbing panel in accordance with the invention.
    Figure 6 shows a photographic embodiment of a semi-finished step of a sound-absorbing panel, which (a) represents a perforated plate, and (b) a perforated plate on which an adhesive layer is applied in accordance with the invention.
    Figure 7 shows another embodiment of a semi-finished step of a sound-absorbing panel, showing a honeycomb core with perforated plate according to the invention, and illustrating sound waves hitting the panel.
    Figure 8 shows an embodiment of a test chart for sound absorption coefficients, which shows the acoustic performance of a sound-absorbing panel in accordance with the invention.
    BE2018 / 5650 Figure 9 shows an embodiment of a sandwich element suitable for use in a sound-absorbing panel, which (a) shows a top view, and (b) a cross-sectional view, in accordance with the invention.
    Figure 10 shows an embodiment of a sound-absorbing panel comprising a large sandwich element with a cut-out part in the middle in cross-section, or two separate sandwich elements next to each other without cut-out parts in cross-section, in accordance with the invention.
    Figure 11 shows an embodiment of an arrangement suitable for use in a method for manufacturing a sandwich element suitable for use in a sound-damping panel, in accordance with the invention.
    Description of the invention
    The invention relates to a sound-absorbing or sound-damping panel comprising a honeycomb sandwich structure, provided with perforations and a covering layer applied thereto for finishing and together therewith thermoformed. The cellular core panel consists of honeycomb cells that are open, i.e. not filled with any material except air.
    As illustrated in Figure 1, the honeycomb cellular core 10 is located between two sheets 13, at least one of which is perforated. The perforation of a sheet is such that approximately one hole or perforation 12 is made per honeycomb cell, and this for each perforated sheet or plate. The honeycomb core is made of paper or cardboard, for example, as well as the (perforated) sheets on it.
    The perforation of at least one sheet of the honeycomb sandwich panel 27 is carried out with the sheets already mounted thereon, i.e. in a semi-finished format.
    The perforation itself is done by means of cutting rollers 21, 22 or drums, or rotating knives, whereby the honeycomb sandwich 27 is produced or advanced, and therefore perforations are made in one or both sides, ie sheets, of the sandwich panel 27, depending on whether the rollers 21, 22 are both provided with blades or not, as shown in Figure 2.
    The perforating device consisting of two rollers is for instance provided with knife carriers instead of the blades being mounted directly on the rollers. below
    For example, with reference to Figure 3, such a knife carrier is formed with a plurality of knife carrier segments, which are designed as circular ring sections 31, which together form an annular shape while forming a single knife carrier. The circular ring segments 31 can be removably mounted on the roller 30 or drum, in an assembly which - together with the knives mounted on the respective knife carriers - forms the cutting drum or the rotating cutting tool. The roll 30 or barrel shape per se, without knife carriers mounted thereon, is typically cylindrical in shape. Multiple knife carriers, each with their circular ring sections 31, can be mounted side by side on the cylindrical roller or drum. The removable nature of the circular ring segments 31 allows flexibility in use and maintenance of the cutting equipment. The blades themselves can be mounted on the multiple knife carriers.
    According to an embodiment, the perforating device comprises two rollers on which a set of half discs, which together form a single disc, is mounted with incisors. In addition to each cutting disc with incisors, a non-cutting disc, i.e. without incisors, is mounted and serves as a spread. The discs with incisors can be mounted such that they rotate in an opposite direction with respect to the angle of intersection of the incisors. As a result of this action, a (controlled shapes) rectangular opening is made in the for example paper or cardboard honeycomb sandwich plate, whereby the material is partially cut and partly pushed in. The cut material has no resistance to return to its original state and thus remains in the hollow honeycomb cell space with paper flaps slid down which also absorb the sound and counteract the springback to leave the plate, but are trapped in honeycomb cells instead , which act as small cavities. A regular distribution of the incisors over the circumference of the roller allows an even distribution of holes. The spreading non-cutting discs ensure an even distribution. The half discs with incisors are mounted in parallel so that they are rotated 90 ° with respect to the previous disc with incisors. This is repeated over the two rollers until a perforation cylinder or cutting drum of a certain length is obtained. This cylinder length is adjustable and expandable based on the number and width of the desired plates and blades, and adaptable to the plate size, design or dimensions. The width of the incisors, the impact of the holes, the depth of the impact, the percentage of the perforated surface and the angle at which the material is pushed away have been developed and
    - 10 BE2018 / 5650 experimentally optimized via acoustic tests. The synchronization between the distance of the openings and the diameter of the internal honeycomb cells is balanced and theoretically as well as practically optimized. The perforation method requires no special force. The sandwich plates are automatically pulled through the machine by the incisors and the rotating movement of the rollers.
    According to an embodiment, the sandwich plates are made of paper type whose fiber direction is determined by production. The direction of movement of the plates, which is directly related to the cutting direction, is important in order to obtain a neat perforation. A good incision is obtained when cutting or perforating perpendicular to the fiber direction. The perforation can be adjusted by means of the height or depth positions of the incisors penetrating the sandwich plate. This permits a certain perforation density or percentage of holes, so that the material can absorb more or less noise or sound waves.
    As already mentioned, the cutting discs are mounted on rollers, side by side, by means of spreads, which are also referred to as non-cutting discs. All sets of half discs are held together with threaded rods that are inserted through the half discs. The entire disk configuration is compressed by means of nuts that are screwed to both ends of the threaded rods. The half discs have a slightly smaller internal diameter than the roller on which they are mounted. In this way, the half discs are stretched on the solid rollers and they can be fixed by means of tension forces without any other attachment being required. All discs together with the associated roll form a single cutting drum and rotate together in the same direction.
    Due to the design of the blades and the settings of the (cutting) rollers through which the honeycomb sandwich panel is guided to provide perforations in at least one sheet (or side) of the panel, the geometry of the perforations can be very specific. In one embodiment, the design of the blades and the settings of the rollers are such that slit-shaped perforations 62 are made, as can be seen in Figure 6. With such slit-like perforations 62, (a part of) the cut material remains on the sheet whereby a remaining flap or tab remains on the sheet of the perforated panel 67. This flap or tab is bent inwards towards the core of the sandwich panel, at a certain angle.
    - 11 BE2018 / 5650
    While the honeycomb core 70 with perforated (one or both) sheets 73 provides acoustic properties, the slit-shaped perforations as mentioned above further weaken by sound-damping properties into favorable acoustic properties due to their geometry, in particular including a folded portion or tab 75 bent under a corner. With such a fold or tab, acoustic waves 71 directed towards the panel are further manipulated, as shown in Figure 7.
    The perforated sandwich panel with honeycomb structure is not necessarily the end product, but a semi-finished phase. To provide an end product such as e.g. a decorative acoustic panel for interior or building interior, the perforated sandwich panel is provided with, for example, a needle felt layer that covers the (paper or cardboard) sandwich structure. Such a needle felt 46 is applied by means of an adhesive layer 49, as shown in Figure 4. This adhesive layer is either first applied to the sheets of the panel and then the needle felt is fixed thereon; or an adhesive layer is pre-applied to the needle felt and attached to the sandwich panel in this assembled format. Instead of needle felt, it is of course also possible to envisage a different type of textile or covering material for applying to the honeycomb core sandwich 40 and perforated sheet or plate 43, such that a finished acoustic panel can be generated.
    According to an embodiment of the invention, the cover or top layers of the acoustic sandwich panels consist of PET needle felt. About 60% of the felt consists of monocomponent thermoplastic polyester fibers. These fibers are completely recycled from transparent PET bottles. The remaining 40% are bi-component fibers of which the core and the outside have a different melting point. These fibers cannot be made from recycled PET bottles and are therefore virgin. The bicomponent fibers determine the stiffness of the felt after thermoforming. It is also possible to color the needle felt. For example, white needle felt can be started with, for example, 5% black fibers as contrast color. The melting point of this felt is higher because the dyeing takes place under high temperature and pressure in an autoclave in order to obtain a good quality of dyeing or coloring, so that the color does not sublimate during thermoforming. Needle felt is produced and supplied as felt rolls, as is well known in the art. The felt rollers are treated with fire retardant
    - 12 BE2018 / 5650 materials. In addition, a glue web is also laminated to the felt rollers to obtain good adhesion between the felt and the perforated honeycomb cardboard sandwich product. The glue web has an open structure, which is needed to allow the sound waves to penetrate the top layers in the core material. The panels can also be finished with even more textiles or decorations, which offers great added value in terms of personalization.
    According to an embodiment of the invention, on the one hand, the grammage (1000 g / m2) of the top layers is chosen to achieve good acoustic absorption, but also to obtain sufficient rigidity at the level of the edges. On the flat surface, where the panel is 35 mm thick, the felt top layers together with the core material provide extra rigidity, flatness and compression resistance. The combination of the perforated honeycomb cardboard sandwich core material with felt top layers scores better on deflection strength and compression resistance than non-perforated honeycomb cardboard sandwich panel without felt top layers. The unique asymmetrical design of the so-called bent edge also provides extra rigidity. An example of an asymmetrical design is e.g. illustrated in Figure 5. The combination of the two materials, i.e. here paper or cardboard and needle felt, ensures that the panels do not bend or hardly bend through suspension due to the material properties of the core material (light, strong, flat). That is why a distinctive design has been achieved. Moreover, this simplifies the suspension system of the panels and the connection fittings.
    The degree of compression of the felt influences the acoustic properties, the stiffness, wear resistance and adhesion between the felt layers at the level of the edges. In the flat portion of the 35 mm thick sandwich panel, the felt is e.g. slightly compressed (5 mm) to achieve maximum acoustic absorption, but still sufficiently durable (Martindale test). At the level of the edges, the two layers of felt - also referred to elsewhere as the extensions of the cover layer - are compressed together, for example, to 4.5 mm in order to obtain good adhesion and sufficient rigidity. This can result in a nice cutting edge after water jets. By perforating the honeycomb cardboard sandwich the compression resistance decreases (without felt). This ensures that the sandwich panel at the level of the edges is easier to compress. Nevertheless, the felt will dilute locally due to the compression resistance of the honeycomb cardboard sandwich. The size of the sandwich panel relative to the mold or mold is crucial to one
    - 13 BE2018 / 5650 qualitative result. Despite a fairly large difference in compression of the felt, a nice even texture can still be obtained. During development, the goal was to limit the compression differences to approximately 1: 2 ratio to achieve a smooth texture. According to an embodiment, the core material must be completely enclosed by the felt top layers to satisfy a certain fire class.
    The unique combination of the acoustic needle felt layer with the perforated cellular core material together ensures excellent acoustic absorption. During the development process, all samples were extensively tested by certified labs in the Kundt tube in order to be able to make correct decisions in perforations, felt programming, felt compression, etc. After producing a few prototype panels, a certified test was done in the reverberation room where acoustic absorption class A was achieved. Moreover, the acoustic absorption can be further improved by increasing the felt programming and increasing the thickness of the felt and / or of the cellular core material.
    However, having the sandwich panel now provided with needle felt glued thereon is yet another semi-finished product before the end product is reached. In fact, the needle felt is not only glued or applied to the perforated (paper) sandwich panel, but it is also thermoformed to be further fixed together and to apply a certain design or geometry to the panel. This specific design or geometry is intended for further improvement of the characteristics of the acoustic panel, either in acoustic sound-absorbing properties, but also in weight and strength, for example. As an example, reference is made to asymmetrical finishing of edges of the panel, leading to more strength of the panel, as illustrated in Figure 5, and showing how a needle felt layer 56 is asymmetrically thermoformed on the sandwich panel 57 with honeycomb core 50 (and provided with first sheet or sheet, not shown). Moreover, the edge of the finished panel is not only asymmetrical in terms of shape, i.e. the edge is bent over to one side, rather than straight, but also asymmetrical in terms of cover material. While on one side the cover layer or the second sheet is a needle felt layer 56, the other cover layer 58 is, for example, made of leather. Figure 5 clearly shows how protruding parts also referred to as extensions, from the applied second sheet 56, 58, can extend across the dimensions of the sandwich panel 57. Such extensions of the
    14 BE2018 / 5650 needle felt layer 56 and of the leather upholstery 56, respectively, can be adhered by means of glue and / or thermoforming.
    The thermoforming process is now described in more detail. According to an embodiment of the invention, a so-called stacking is formed of the different layers:
    - 1000 gr / m 2 40% bi-component fiber needle felt (FR-treated + laminated glue web)
    - Perforated cardboard sandwich of 25 (with middle markings)
    - 1000 gr / m2 40% bi-component fiber needle felt (FR-treated + laminated glue web)
    The entire stacking, including perforated sandwich core and cover layers, is heated in a convection oven at 180 ° C for less than 10 minutes. The cardboard is resistant to this heat. In the meantime, the thermoplastic adhesive web fuses onto the cardboard. The stacking is then placed centrally in the aluminum-cooled mold. The mold is then closed at a pressure of about 5 to 10 kg / cm 2. Adjustable thickness limiting pins can help in positioning the mold halves. In one embodiment, the open time, i.e., the time from opening the oven until the mold is on pressure, must fluctuate around 90 seconds. The piece is then cooled for a few minutes in an aluminum-cooled mold. In the new design of the panel, a kind of guiding system must be used, also known as a delay ring that slightly stretches the felt to prevent creases. The piece can then be formatted on a stainless steel or stainless steel caliber on a water jet machine.
    Because of the slit-like perforations, the panel, while retaining its strength, is better in compressibility, and thus better in processing during thermoforming, particularly when specific geometry is performed, such as, for example, curved edges.
    It is noted that dimensions of the honeycomb core cells, perforations, and layers (e.g., layer thickness as size) of the sandwich panel structure are well chosen and are related to each other. Moreover, the forces exerted on the panel are made in semi-finished products, for example during processing
    - BE2018 / 5650 perforating or thermoforming is not chosen at random, but the strength of the structure is taken into account.
    Tests on the acoustic properties have been carried out, resulting in figures indicating the performance of the sound-absorbing panel in accordance with the invention. As an example, reference is made to a graphic representation in Figure 8, which shows the sound absorption coefficient as a function of the frequency, of a series of prototype panels according to the invention, placed horizontally against each other, with an overlapping edge, and at a distance of 15 cm from ceiling or ground surface in a closed test environment. This graph or the accompanying figures also indicate that the prototype panels can have a class A rating with regard to sound absorption according to the standard ISO 11654 with regard to acoustics, more particularly with regard to sound-absorbing products or materials for use in buildings, and according to the assessment of sound absorption, as widely used in Europe. With regard to the measurement of sound absorption coefficient as described here, and more particularly the graphical representation thereof as illustrated in Figure 8, reference is also made to the paper Sound absorption coefficient measurement: Re-examining the relationship between impedance tube and reverberant room methods ” from McGrory et al., Proceedings of Acoustics 2012, Fremantle - Australia, dd. November 21-23, 2012. As shown in Figure 8, values above 1, i.e., greater than the unit for the sound absorption coefficient, are shown. In the aforementioned article an explanation is given for such values, while the absorption coefficient is defined as the relationship between the acoustic energy absorbed by a material and the total incident energy affecting it. The article states that this coefficient must be limited between 0 (completely non-absorbent, ie reflective) and 1 (fully absorbent), although absorption coefficient values greater than 1 can be found for various reasons including edge diffraction, non-diffusity and Sabine formulation such as further discussed therein.
    Fig. 9 illustrates an embodiment of a sandwich element 170 suitable for use in a sound-absorbing panel 200 in accordance with the invention. Figure 9 (a) shows a top view illustrating the cellular element 100 or the core structure consisting of a plurality of small cells 110 with a regular geometric shape, such as e.g. a hexagonal or hexagonal shape, and so such small cells 110 are also often referred to as honeycomb cells. In
    BE2018 / 5650 Figure 9 (b) is a cross-sectional view of the sandwich element 170, comprising a first sheet 130, such as, for example, a cardboard layer on top of the cellular element 100, which is, for example, a cardboard core and hollow as a structure. Optionally on both sides, but according to an embodiment at least on one side, the first sheet 130 is provided with perforations 120, as shown in the top view of Figure 9 (a). Such perforations 120 may have a slit-shaped rectangular shape. During the perforation process, for making such perforations 120, a portion of the material of the first sheet 130 remains adhered or adhered to the first sheet 130, although bent, and can be described as a kind of small flaps or tabs that go inward are directed or bent inwards toward the cells 110 of the core 100. The sandwich element 170 also comprises a second sheet 160 disposed on the top of the first sheet 130, on both sides of the core structure 100. This second sheet 160 is, for example, a needle felt or another type of textile layer or covering layer of the sandwich element 170. According to In one embodiment, the second sheet 160 extends over the surface of the cellular core provided with the first sheet. Such an extension is illustrated by means of so-called extensions 180 as further illustrated in Figure 9 (b), and defined as extending portions over the dimensions of the cellular element 100, provided with the first sheet 130 on both sides. Such extensions are 180 for example, very useful in finishing the product, ie sandwich element 170, during the thermoforming process and ultimately making a sound-absorbing panel 200.
    Figure 10 shows an embodiment according to the invention of a sound-absorbing panel 200, in cross-section, which can either be interpreted as comprising a large sandwich element 170 with a cut-out part in the middle, or comprising two sandwich elements 170 (with common second sheet 160) next to each other without cut-outs, and assembled during the thermoforming process, by means of which the second sheet 160 is glued and / or thermoformed on its extensions 180, and therefore thereon bonded or fixed extensions by thermoforming (whether or not in combination with glue) 210 are made. In the case of the sandwich element 170 with cut-out portion, the cut-out portion is typically cut out after the sandwich panel 170 provided with the first sheet 130 is perforated and just before the second sheet 160 is mounted thereon. In the case of two separate sandwich elements 170 spaced apart as core with the first sheet 130 and
    17 BE2018 / 5650 then aligned and assembled, the second sheet 160 of both sandwich elements 170 is not only provided with extensions but is, moreover, sufficiently large so that it can be used in common for both sandwich elements 170.
    According to an embodiment of the invention, a perforating machine 340 is described with reference to Figure 11, suitable for use in a method for manufacturing a sandwich element 170 which is suitable for use in a sound-damping panel 200. The perforating machine 340 is adapted to receive of a cellular element 100 provided with a first sheet 130 thereon, more particularly on either side of the cellular element 100, between at least one cutting drum 300 provided with knives 310 and a conductive carrier 320 for guiding the sandwich element.
    According to an embodiment of the invention, an arrangement 600 is further described with reference to Figure 11, suitable for use in a method for manufacturing a sandwich element 170 which is suitable for use in a sound-damping panel 200. The arrangement 600 is adapted to receiving the cellular element 100 with first sheet 130 disposed thereon, and first sheet 130 perforated on at least one side of the cellular element 100. The arrangement 600 is also adapted to apply a second sheet 160 to the first sheet 130. The set-up 600 includes an oven 400 for preheating 410 the sandwich element, or a heated mold for directly performing the thermoforming process. In one embodiment, the array 600 includes, next to the oven 400, and as part of indirect or 2-step thermoforming 510, means such as a pressure mold 500 for applying mechanical pressure 510 to at least the extensions 180 of the second sheet 160 of the preheated sandwich element, or completely on the second sheet of the pre-heated sandwich element.
    A decorative sound-damping panel with improved acoustic properties is provided with the invention, wherein the panel is perforated and is based on a honeycomb core and thermoformed in an improved manner.
    权利要求:
    Claims (19)
    [1]
    A sandwich element (170) suitable for use in a sound-damping panel (200), the sandwich element (170) comprising: a cellular element (100), and a first sheet (130) disposed on both sides of the cellular element (100) ), wherein the first sheet (130) comprises perforations (120) on at least one side of the cellular element (100), and characterized in that a portion (150) of the material of the first sheet (130) comprises perforations (120) remains attached to the first sheet (130), the cellular element (100) and / or the first sheet (130) being made of paper or cardboard.
    [2]
    A sandwich element (170) suitable for use in a sound-damping panel (200), the sandwich element (170) comprising: a cellular element (100), and a first sheet (130) disposed on both sides of the cellular element (100) ), wherein the first sheet (130) comprises perforations (120) on at least one side of the cellular element (100), and characterized in that a portion (150) of the material of the first sheet (130) comprises perforations (120) comprises adhered to the first sheet (130), further comprising a second sheet (160) disposed on the first sheet (130), the second sheet (160) being thermoforming and made of, for example, needle felt textile.
    [3]
    The sandwich element (170) according to claim 1 or 2, with a geometric shape, such as for example a rectangular or oval or circular or a polygon shape.
    [4]
    The sandwich element (170) according to claim 1, 2 or 3, wherein one or more parts of the sandwich element (170) are cut out.
    [5]
    The sandwich element (170) according to claim 4, wherein the one or more parts are provided with a further geometric shape, such as for example a rectangular or oval or circular or a polygon shape, smaller and possibly different from the geometric shape of the sandwich element (170) ).
    [6]
    The sandwich element (170) according to claims 1 to 5, wherein the cellular element (100) comprises a honeycomb structure.
    [7]
    The sandwich element (170) according to any of claims 2 to 5, wherein the cellular element (100) and / or the first sheet (130) are made of paper or cardboard.
    [8]
    The sandwich element (170) of claim 1, further comprising a second sheet (160) disposed on the first sheet (130).
    [9]
    The sandwich element (170) according to claim 8, wherein the second sheet (160) is suitable for thermoforming and is, for example, made of needle felt textile.
    - 19 BE2018 / 5650
    [10]
    The sandwich element (170) according to claim 8 or 9, wherein the second sheet (160) consists of extensions (180) which are defined as the elongate pieces along the dimensions of the cellular element (100) provided on both sides with the first sheet (130).
    [11]
    The sandwich element (170) according to claims 2 to 10, wherein the cellular element (100) and / or the first sheet (130) and / or the second sheet (160) are connected to an adhesive such as glue.
    [12]
    The sandwich element (170) according to claims 2 to 10, wherein the second sheet (160) is thermoformed on the first sheet (130).
    [13]
    The sandwich element (170) according to claim 10, wherein the extensions (180) are connected to an adhesive such as glue and / or thermoformed as bonded extensions (210).
    [14]
    A sound-damping panel (200) comprising one or more of the sandwich elements (170) according to claims 1 to 13.
    [15]
    A method of manufacturing a sandwich element (170) according to claims 1 to 13, comprising the steps of: providing a cellular element (100), providing a first sheet (130) on both sides of the cellular element (100), and then perforating (330) the first layer (130) on at least one side of the cellular element (100), the cellular element (100) and / or the first sheet (130) being made of paper or cardboard.
    [16]
    The method of claim 15, further comprising: providing a second sheet (160) on the first sheet (130), wherein providing the second sheet (160) on the first sheet (130) is by thermoforming .
    [17]
    The method of claim 15 or 16, wherein applying the first sheet (130) to both sides of the cellular element (100) is by using an adhesive such as glue.
    [18]
    The method of claim 15 or 17, wherein providing the second sheet (160) on the first sheet (130) is by means of an adhesive such as glue.
    [19]
    A sandwich element (170) suitable for use in a sound-damping panel (200), the sandwich element (170) comprising: a cellular element (100), and a first sheet (130) disposed on both sides of the cellular element (100) further comprising a second sheet (160) disposed on the first sheet (130), wherein the second sheet (160) is thermoforming and is, for example, made of needle felt textile.
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    同族专利:
    公开号 | 公开日
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    GB1470036A|1975-01-17|1977-04-14|Lockheed Aircraft Corp|Dual range sound absorber|
    US5895699A|1996-03-15|1999-04-20|The Boeing Company|Tiedown ply for reducing core crush in composite honeycomb sandwich structure|
    US20020036115A1|2000-06-30|2002-03-28|Short Brothers Plc|Noise attenuation panel|
    US20100284789A1|2009-05-05|2010-11-11|Rolls-Royce Plc| damping assembly|
    US20150064377A1|2011-08-01|2015-03-05|Corcel Ip Limited|Laminated board|
    US20130243998A1|2012-03-07|2013-09-19|Airbus Operations Gmbh|Sandwich component|
    US20130341119A1|2012-06-26|2013-12-26|Hexcel Corporation|Structure with active acoustic openings|
    法律状态:
    2020-01-29| FG| Patent granted|Effective date: 20191223 |
    优先权:
    申请号 | 申请日 | 专利标题
    BE201805530|2018-07-20|
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