EP3581065B1

EP3581065B1 - Table with sound-absorbing properties

Info

Publication number: EP3581065B1
Application number: EP19000287.3A
Authority: EP
Inventors: Antonio SCOFANO
Original assignee: Prototypo Srl
Current assignee: Prototypo Srl
Priority date: 2018-06-14
Filing date: 2019-06-12
Publication date: 2021-08-25
Anticipated expiration: 2039-06-12
Also published as: EP3581065A1; IT201800006329A1

Description

FIELD OF APPLICATION

The present invention refers to a piece of furniture with sound-absorbing properties. In particular the present invention refers to a table having sound-absorbing properties.

STATE OF THE ART

As known, the prolonged exposition to noise, especially in public places, can result in stress, nervousness, miscommunication, but also physical issues such as migraine.
In a crowded venue, such as a coffee shop, a restaurant, a canteen, a sound pressure level of 95dB can be reached, which represents a risk threshold not only for the people who work in those environments, but also for the patrons. Furthermore, particularly noisy venues, are often not desirable to customers who prefer venues where it is possible to hold a conversation in peace.
In fact, these levels of sound pressure, cause an additional negative aspect, the so called Lombard effect, and that is the involuntary tendency of speakers to increase their tone of voice in the presence of a background noise. The negative aspect primarily refers to the increase of the vocal effort which may cause a considerable strain on the vocal cords.
There are other secondary negative effects tied to other acoustic features such as the pitch, the rhythm and the syllabic duration.
The same conditions also occur in workplaces, typically offices, where dividing walls are not present between the spaces intended for employees, namely "open spaces". These units of modern offices have to be flexible, and capable to rapidly adapt themselves to possible organizational changes. Some companies decide to create non-territorial spaces, meaning that employees no longer have an assigned space, but they can choose their workstation for example each day, or weekly, depending on the different requirements (for example temporary work groups, and so on).
Furthermore, the construction methods and the design, impose an overall increase of transparency in buildings, and therefore an increase of hard materials such as glass and cement. These kind of surfaces, hard and homogenous reflect sound in an unnatural way, contributing to sound propagation and to an overall increase in reverberation time.
In order to overcome these issues, it is known to implement acoustic panels for the so called correction and acoustic remediation of the environments.
Generally, sound-absorbing panels are used in correspondence with the perimeter of a room, and preferably integrated into the walls, or onto the surfaces that are used to divide an environment. These panels can also be placed in correspondence with the ceiling, a solution that is typically implemented in environments of considerable size such as canteens or university study rooms.
These types of acoustic remediation works, entail the positioning of the sound-absorbing products far from the acoustic sources, which therefore have moderate efficacy. If we consider for example a restaurant hall or a coffee shop, the majority of noise sources, are not close to the walls, and therefore people are often disturbed by the chattering of other groups of people located nearby.
For these reasons, the prior art makes some alternatives available to the panels placed on the sides and in correspondence with the ceiling of environments, like for example sound-absorbing armchairs or sofas, or sound-absorbing lampshades.
However, the pieces of furniture now mentioned, but also the panels referred to above, are made with materials of porous or fibrous nature, within which dust, humidity and allergens can settle and are difficult to remove from. This issue is amplified in the case of public places such as restaurants or coffee shops where there is a large inflow of people from the outside.
Furthermore, these materials are inflammable, hence some measures must be implemented, as required by law, in order to make these materials safe.
In addition, the materials normally used are cumbersome and also for this reason they negatively impact the perception of the architectural space.
In the aeronautic field it is known to use a particular type of sound absorbing panel which takes advantage of Helmholtz resonance theory, implemented onto the internal surfaces of the engine nacelles. The same system is also applied in some internal combustion engines. Helmholtz resonance theory takes shape in a resonator, which represents a class of sound-absorbing systems by resonance in a cavity, composed of a rigid cavity having a given volume, connected to the outside by means of a small opening, called neck of the resonator, having a given length and a given cross-section.
As known, from a physics point of view, the resonator behaves as an oscillating piston, observing the mass-spring principle. The so created system is characterized by its own frequency to which it resonates. In correspondence with the resonating frequency there is a remarkable dissipation of acoustic energy by means of air friction with the surface of the neck, and therefore a considerable absorption of sound.
Helmholtz resonators are characterized by a sound-absorption curve centered on a unique resonance frequency and consequently their efficacy is limited to a restricted range of frequencies and centered on the resonance frequency. However, it can be built and calibrated to be versatile to the frequencies of interest.
Practically a panel of this kind is made of three components:

an acoustically reflective lower layer;
a finishing layer permeable to air; and
a middle layer consisting of an alveolar structure.

Since the resonance frequency primarily depends on the following factors:

thickness of the panel;
size of the holes of the panel;
size of the base of the cavity of the alveolar structure;
percentage of perforation of the panel; and on the
assembling distance from the side on which the panel is placed;

However, as noted above, interior space acoustics works are primarily carried out using porous materials which have their flaws and limitations as discussed above.

SUMMARY OF THE INVENTION

It was therefore deemed necessary to find a solution to the mentioned drawbacks and limitations in relation to the prior art.
Therefore the need is felt to make a piece of furniture with sound-absorbing properties available that is effective in increasing speech intelligibility and therefore the hearing at a short distance from the interlocutor.
Furthermore, the need is felt to make pieces of furniture with sound-absorbing properties available which can also be used in central locations of an environment or of a room.
Furthermore, the need is felt to achieve high sound-absorption levels in crowded environments such as coffee shops or canteens.
The need is also felt to make pieces of furniture with sound-absorbing properties available that are less exposed to dust, dirt and allergens, and that are easily cleaned.
Moreover, the need is felt to make pieces of furniture with sound-absorbing properties available that are fire-resistant, and thus are not subject to specific safety regulations.
These needs are satisfied by a table in accordance with claim 1.

DESCRIPTION OF THE DRAWINGS

Additional features and the benefits of the present invention will be better understood from the foregoing description by way of illustration and preferred example only and it is not intended to limit the scope of the claims in any manner, in which:

figure 1 depicts a schematic representation of a perspective view of a table in accordance with the present invention;
figure 2 depicts a perspective expanded deconstructed view of a section of the table in accordance with the present invention;
figure 3 depicts a perspective expanded deconstructed view of a part of the table in an alternative embodiment in accordance with the present invention; and
figure 4 depicts a perspective deconstructed view of a portion of the table in accordance with the present invention.

The components or portions of components in common between the embodiments described hereafter will be indicated with the same numerical references.

DETAILED DESCRIPTION

In figure 1 with reference 12 is generally indicated a table with sound-absorbing properties according to the present invention.
The table 12 comprises at least one support plane 14, having a finishing layer 16 and a lower layer 20, and support means 18 for the support plane 14.
The finishing layer 16 is permeable to air, and is intended to achieve an external finish of the support plane 14. The support plane 14 comprises, between the finishing layer 16 and the lower layer 20, at least one resonant inner layer 22 comprising an alveolar structure 24.
According to a further embodiment of the present invention, the finishing layer 16 and the lower layer 20 can extend in parallel with a main extension plane and are overlaid with respect to an orthogonal direction with respect to said main extension plane.
In an alternative embodiment of the present invention, the lower layer 20 may be realized with a curved surface, for example so that the distance between the finishing layer 16 and the lower layer 20 be greater in correspondence with a central portion.
In these types of solutions, the resonant inner layer may have variable thickness.
With reference to a cross-section of the support plane, the section can be for example of rectangular shape, curved, as a truncated pyramid, and so on. In this case, the resonant inner layer may have variable thickness in order to fill the particular shape of the cavity realized between finishing layer 16 and lower layer 20.
According to the present invention the finishing layer 16 is permeable to air, through micro holes. Advantageously, the micro holes may have a diameter comprised between 300 µm and 150 µm.
In alternative embodiments, the micro perforation can be realized by means of metal meshes.
Since the finishing layer 16 is micro-perforated, the acoustic waves coming from the environment can penetrate in order to be subsequently damped inside the support plane 14, as better described hereafter.
According to a further embodiment of the present invention, the finishing layer 16 can be made of an acoustically insulating material.
In particular, the finishing layer 16 can be made of acoustically insulating laminar material, but through the passing micro holes, the sound waves impacting on it can be absorbed. Furthermore, the finishing layer 16 may also comprise a non-micro-perforated area.
In regards to the lower layer 20, it can be made of an acoustically reflective material.
Advantageously, the lower layer 20 can be made of metal laminate of aluminum or its alloys.
In accordance with a further embodiment of the present invention, the lower layer 20 may be made of for example wood, polymeric materials, and so on.
In accordance with the present invention, the alveolar structure 24 is suitable for making a plurality of resonant cavities 26.
The alveolar structure 24 can have a thickness between 10 mm and 100 mm, and preferably between 20 mm and 70 mm. The thickness is intended to be measured as the distance between the upper and the lower surface of the alveolar structure 24.
In accordance with a further embodiment of the present invention, the resonant cavities 26 may have a hexagonal cross-section.
In accordance with further embodiments of the present invention, the cavities may have a section different from the hexagonal section, for example triangular or square.
The alveolar structure 24, and in particular the resonant cavities 26 have variable shape and / or the thickness of the alveolar structure 24 varies depending on the location of said alveolar structure.
According to the invention the variation of the geometry and/or of the thickness alters the acoustic impedance of the panel and allows to obtain a panel suited to dampen a broader range of frequencies.
In fact, the alveolar structures 24 function acoustically as Helmholtz resonators.
The resonant inner layer 22 can be made of aluminum or its alloys.
In accordance with alternative embodiments of the present invention, the resonant inner layer may be realized also in cardboard, wood, and so on. These kinds of materials might be used for example in the case of lower-priced embodiments, or for example in the event of less stringent fire regulations.
In accordance with a further embodiment of the present invention, the lower layer 20 can comprise a raised perimeter edge 28, suitable for containing the resonant inner layer. Advantageously, the raised perimeter edge 28 can be suitable for containing also the lateral surface of the finishing layer 16.
In accordance with a further embodiment of the present invention, the finishing layer 16 can be partially covered by the raised perimeter edge 28. The fastening between the resonant inner layer 22, the lower layer 20 and the finishing layer 16 can be realized using reversible type inserts (not shown). In possible embodiments, these reversible type inserts can be disassembled and/or adjusted.
In accordance with a possible embodiment of the present invention, the support plane 14 is fastened to the lower layer 20 or to the raised perimeter edge. In this case, the resonant inner layer can be latched between the finishing layer 16 and the lower layer 20 since it is packed up between said layers.
In the embodiment shown in figure 1, the entire support plane 14 of the table 12 is comprised of a finishing layer 16, a resonant inner layer 22 and a lower layer 20. In alternative embodiments, at least one portion of the support plane is comprised of a finishing layer 16, a resonant inner layer 22 and a lower layer 20.
In accordance with a possible embodiment of the present invention, the support means 18 can include a base 30 and a load-bearing column 32 for the support plane 14 of the table 12.
Referring to figure 3, inside the support plane 14, a support plate 34 can be placed, in particular between one resonant inner layer 22 and the lower layer 20. In this regard, the support plate 34 can be fastened to the resonant inner layer 22. The fastening can be made for example by means of screws 36 that are screwed in the correspondent places 38 prearranged on the resonant inner layer 22.
The support plate 34 can be prepared with a plate hole 40 suitable to engage with a threaded rod 42.
The load-bearing column 32 can be hollow, in order for the threaded rod 42 to pass through it and protrude from both extremities. One extremity of the threaded rod 42 can therefore be screwed to the support plate 34, and the other extremity can be fixed to the base 30. In this respect, the base 30 can present a base hole 44, which can be threaded and is therefore suited to be paired with the threaded rod 42, or it can be suitable for allowing the threaded rod 42 to pass through so that it can be paired with a correspondent insert 46 also threaded.
In accordance with a further embodiment of the present invention, the lower layer 20 can be conceived with an opening 48, so that the load-bearing column 32 can be inserted until it reaches the correct position with the support plate 34. Advantageously, the opening 48 can be a matrix of the cross-section of the load-bearing column 32.
In accordance with a further embodiment of the present invention, the table can have a square supporting surface having side of 700 mm, and can have a height of 740 mm. Advantageously, it can be combined with other units to extend the supporting surface, or it can be realized with other dimensions.
In accordance with alternative embodiments of the present invention, the table could be conceived with support means 18 of a different type. For instance it can be conceived with multiple load-bearing columns, for example two, or four.
In further embodiments the support can be conceived differently, for example at one extremity of the support plane 14, in the case of essentially a shelf type table.
Furthermore, the support plane 14 could be that of a countertop and hence the support system of the support plane could be an almost continuous structure upon which the plane is based.
Hence the advantages that can be achieved with a piece of furniture according to the present invention are clear.
Firstly, with the present invention, a table with sound-absorbing properties has been made available which can easily be placed near the areas where chatter develops. Therefore speech intelligibility is improved, since the background noise of conversations coming for example from near-by groups of people gets absorbed by tables placed in their proximity.
Essentially, the table in accordance with the present invention allows the absorption of sound waves close to their source, the human voice, and consequently it is achieved in a more effective way compared to the systems of the prior art.
For the same reason, the hearing at a short distance from the interlocutor is improved.
By means of the table in accordance with the present invention, it is possible to achieve high levels of sound absorption in very crowded places such as coffee shops, or canteens. It is therefore possible to significantly reduce the sound pressure.
In particular, the sound absorbing properties are retained even when the table is set up, for example with placemats, cutlery, glasses.
Additionally, the table with sound absorbing properties in accordance with the present invention is less exposed to dust, dirt and allergens, and it is easily cleaned. In particular, in the case in which the finishing layer is micro-perforated with holes having diameter values of approximately 100 µm, the supporting surface will be water-repellent and therefore easy to clean and stain-resistant.
Additionally, the table in accordance with the present invention is fire-resistant, and therefore is not subject to specific safety regulations.
Furthermore it is possible to make the table particularly effective in the range of frequencies of the spoken language hence in the 500-2000Hz range.

Claims

Table (12) comprising a support plane (14) having
a finishing layer (16), and support means (18) for said support plane (14);
wherein said finishing layer (16) is permeable to air, and is intended to achieve an external finish of the support plane (14); and wherein said support plane (14) comprises a lower layer (20), between said finishing layer (16) and said lower layer (20) there being present at least one resonant inner layer (22) comprising an alveolar structure (24);
wherein the finishing layer (16) is permeable to air through micro holes; and in that alveolar structure (24) is able to realize a plurality of resonant cavities (26);
characterized in that the resonant cavities (26) have variable shape and/or thickness depending on the location of said alveolar structure, such variation altering the acoustic impedance of the panel, wherein said resonant cavities (26) acoustically act as Helmholtz resonators.
Table (12) according to claim 1, characterized in that the finishing layer (16) and the lower layer (20) extend parallel to a main extension plane and are superposed with respect to an orthogonal direction with respect to said main extension plane.
Table (12) according to any one of the preceding claims, characterized in that said micro holes having a diameter between 300 µm and 150 µm, preferably approximately 100 µm.
Table (12) according to any one of the preceding claims, characterized in that the finishing layer (16) is made of an acoustically insulating material.
Table (12) according to any one of the preceding claims, characterized in that the lower layer (20) is made of an acoustically reflective material.
Table (12) according to any one of the preceding claims, characterized in that the alveolar structure (24) has a thickness between 10 mm and 100 mm, and preferably between 20 mm and 70 mm.
Table (12) according to any one of the claims 6, characterized in that the resonant cavities (26) have a hexagonal cross-section.
Table (12) according to any one of the preceding claims, characterized in that the resonant inner layer (22) is made of aluminum or its alloys.
Table (12) according to any one of the preceding claims, characterized in that the lower layer (20) comprises a raised perimeter edge (28), suitable for containing the resonant inner layer.
Table (12) according to the preceding claim, characterized in that the raised perimeter edge (28) is suitable to contain the lateral surface of the finishing layer (16).
Table (12) according to any one of the preceding claims, characterized in that said support means (18) comprise a base (30) and a load-bearing column (32) for said support plane (14) of said table (12).
Table (12) according to any one of the preceding claims, characterized in that it is coupled with an acoustic diffuser in which the diffusion produced by said acoustic diffuser is directed towards the support plane (14).
Table (12) according to any one of preceding claims, characterized in that the support plane (14) has a cross-section having rectangular, curved, or truncated pyramid shape.
Table (12) according to claim 13, characterized in that the thickness of the resonant inner layer (22) is such to fill the shape of the space realized between finishing layer (16) and lower layer (20).