Patent Description:
This section illustrates useful background information without admission of any technique described herein being representative of the state of the art.

Various wall materials and structures have been developed for soundproofing purposes. Furthermore, various acoustical surface materials, such as acoustical panels and fabrics, have been developed to improve the sound quality or characteristics in a space.

In small spaces, such as in phone booths or conference rooms for open-plan offices, the soundproofing and sound quality is of foremost importance and challenging to control because of space restrictions.

Existing solutions for soundproofing and acoustics are often expensive or difficult to assemble. Furthermore, they often require lot of space leading to bulky and unwieldy structures.

<CIT> discloses a door panel comprising a core material formed of two insulation foam elements sandwiched between two steel facings and comprising a hollow space or air gap located within the core. The core material used in D4 is a semi-rigid, cellular material containing more than <NUM> % open cells. A pine timber frame runs around the four sides of the door panel to provide stiffness and hard edges.

The present invention aims to mitigate the disadvantages of the prior art by providing a compact soundproof wall structure that also ensures sound quality in the soundproofed space.

According to a first example aspect of the present invention, there is provided a wall structure, comprising the following elements in the following order:.

The at least one layer of the first stopping element may comprise metal.

The at least one layer of the first stopping element may have a thickness between <NUM>,<NUM> and <NUM>, preferably of <NUM>.

The at least one layer of the second stopping element may comprise material chosen from the group of plywood, hardboard, plastic, composite, metal and a combination thereof.

The at least one layer of the second stopping element may have a thickness between <NUM> and <NUM>, preferably of <NUM>.

The first dampening element may comprise a first layer comprising porous or open cell material and a second layer comprising porous or open cell material.

The material of the first layer may have a density between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably about <NUM>/m<NUM> and the material of the second layer may have a density between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably of about <NUM>/m<NUM>.

The first layer may have a thickness between <NUM> and <NUM>, preferably of <NUM> and the second layer may have a thickness between <NUM> and <NUM>, preferably of <NUM>.

The material of the fourth layer may have a density between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably of about <NUM>/m<NUM>.

The fourth layer may have a thickness between <NUM> and <NUM>, preferably of <NUM> and the fifth layer may have a thickness between <NUM> and <NUM>, preferably of <NUM>.

The wall structure may further comprise a frame element at both ends of the structure.

According to a second example aspect of the present invention, there is provided a phone booth, comprising walls comprising the wall structure of the first example aspect of the invention.

According to a third example aspect of the present invention, there is provided a method of manufacturing the wall structure of the first example aspect of the invention by.

The present invention and its potential advantages are understood by referring to <FIG> of the drawings. In this document, like reference signs denote like parts or steps.

<FIG> shows a principle view of a phone booth for example in which an embodiment of the invention is used. The phone booth <NUM> comprises walls <NUM> and a door <NUM>. The wall structure <NUM> (<FIG>) according to an embodiment of the invention is for example used in the walls <NUM> of the phone booth <NUM>. The wall structure <NUM> according to an embodiment of the invention is further used for example as an additional structure on top of an existing wall in order to increase acoustics and sound dampening of the space in which the existing wall is situated. Furthermore, the wall structure <NUM> according to the invention is for example used in vehicles, in engine rooms and in encapsulation, housing or casings of different kinds for example for machines.

<FIG> shows a schematic view of a cross section of a wall structure <NUM> according to an embodiment of the invention. The cross section shown is in direction perpendicular to the wall with the inner surface of the wall shown lower and the outer surface shown higher. The wall structure <NUM> comprises a first dampening element A, a first stopping element B, a second dampening element C and a second stopping element D the structure and function of which will be described hereinafter. Furthermore, the wall structure <NUM> comprises a frame element <NUM>, at both ends of the structure. In an embodiment, the frame element <NUM> comprises material such as plywood, hardboard, plastic, composite, metal or a combination thereof. In an embodiment, the material of the frame element <NUM> has certain characteristics as hereinafter described.

The wall structure <NUM> in a further embodiment further comprises support elements <NUM>,<NUM> on both ends of the wall structure <NUM>. In an embodiment, the support elements <NUM>,<NUM> comprise material such as plywood, hardboard, plastic, composite, metal or a combination thereof. In further embodiment, the support elements <NUM>,<NUM> are integrated with the frame elements <NUM>.

<FIG> further shows the layers of the elements A,B,C,D of the wall structure <NUM> configured to provide for the acoustic and soundproofing effect. In an embodiment, the layers and the elements of the wall structure <NUM> are attached to each other in a conventional manner, for example using glue.

Starting from the inner surface of the wall structure <NUM>, the fist dampening element A of the wall structure comprises a first, or inner surface, layer 20a configured to provide for the acoustic and soundproofing effect. The first layer <NUM> comprises porous or open cell material and is configured to form an acoustical inner surface of the wall with desired acoustical properties, i.e. configured to let certain sound frequencies pass in order to improve the acoustical properties of the space. The first layer 20a comprises material that is resistant to wear and permeable to air, i.e. breathing. In an embodiment, the first layer 20a comprises material such as felt, foam rubber, polyester fibre, glass wool, rock wool, mineral wool, canvas, canvas covered material or a combination thereof. In an embodiment, the density of the first layer 20a is between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably of about <NUM>/m<NUM>.

The first dampening element A of the wall structure <NUM> further comprises, after the first layer 20a, a second, or inner damping, layer 20b configured to provide for the acoustic and soundproofing effect. The second layer 20b comprises porous or open cell material and is configured to absorb and dampen the sound. In an embodiment, the second layer 20b comprises material such as felt, foam rubber, polyester fibre, glass wool, rock wool, mineral wool or a combination thereof. In an embodiment, the density of the second layer 20b is between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably of about <NUM>/m<NUM>.

The first stopping element B of the wall structure <NUM> comprises, after the second layer 20b, a third, or stopping, layer <NUM> configured to provide for the acoustic and soundproofing effect. The third layer <NUM> comprises material configured to stop sound. In an embodiment, the material of the third layer <NUM> comprises metal or medium-density fibreboard (MDF). In an embodiment, the material of the third layer has an area density of <NUM> to <NUM>/m<NUM>. In a further embodiment, the material of the third layer <NUM> comprises steel, lead, or copper. In an embodiment, the third layer <NUM> is sandwiched between the support elements <NUM>,<NUM> as shown in <FIG>.

The second damping element C of the wall structure <NUM> comprises, after the third layer <NUM>, a fourth, or outer damping, layer <NUM> configured to provide for the acoustic and soundproofing effect. The fourth layer <NUM> comprises porous or open cell material and is configured to absorb and dampen the sound. In an embodiment, the fourth layer <NUM> comprises material such as felt, foam rubber, polyester fibre, glass wool, rock wool, mineral wool or a combination thereof. In an embodiment, the density of the fourth layer <NUM> is between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably of about <NUM>/m<NUM>.

The second damping element C of the wall structure <NUM> comprises, after the fourth layer <NUM>, a fifth, or air, layer <NUM> configured to provide for the acoustic and soundproofing effect. The fifth layer <NUM> comprises an air gap configured to form together with the fourth layer a dampened air gap in order to dampen sound.

The second stopping element D of the wall structure <NUM> comprises, after the fifth layer <NUM>, a sixth, or outer, layer <NUM> configured to provide for the acoustic and soundproofing effect. The sixth layer is configured to form the outer surface of the wall structure <NUM> and comprises material configured to stop the sound. In an embodiment, the sixth layer <NUM> comprises material such as plywood, hardboard, plastic, composite, metal or a combination thereof. In an embodiment, the material of the frame element <NUM> has certain characteristics as hereinafter described. In a further embodiment, the wall structure <NUM> comprises one or several additional air gaps configured to dampen sound in between the elements described hereinbefore. In a still further embodiment the air gap <NUM> and/or further air gaps are configured to, in addition to dampening sound, to be used as channels for electrical wiring and the like.

In an embodiment, for example as the wall structure <NUM> is used in a phone booth <NUM> of <FIG>, the material of the frame elements <NUM>, the outer layer <NUM> and the support elements <NUM>,<NUM> comprises material having certain characteristics. In an embodiment, the material has a module of elasticity perpendicular to the surface larger than about <NUM> N/mm<NUM>, a module of elasticity parallel to the surface larger than about <NUM> N/mm<NUM> and a flexural strength larger than about <NUM> N/mm<NUM>.

The wall structure <NUM> according to embodiments of the invention provides for a compact size while retaining soundproofing and acoustical quality. Accordingly, the dimensions of the layers of the wall structure are chosen so that the thickness of the wall structure <NUM> is between <NUM> and <NUM>, preferably between <NUM> and <NUM>, and more preferably about <NUM>. In an embodiment, as an example, the thickness of the first to sixth layers is as follows.

<FIG> shows a further schematic view of a cross section of a wall structure <NUM> according to an embodiment of the invention. The frame elements <NUM>, the support elements <NUM>,<NUM> and the third to sixth layers <NUM>-<NUM> have a structure as hereinbefore described with reference to <FIG>. The first damping element of the wall structure <NUM> comprises at the inner surface thereof a first, or inner surface and damping, layer <NUM> configured to provide for the acoustic and soundproofing effect instead of the first layer 20a and second layer 20b as described with reference to <FIG>.

The first layer <NUM> comprises porous or open cell material configured to form the inner surface of the wall with desired acoustical properties, i.e. configured to let certain sound frequencies pass in order to improve the acoustical properties of the space. Furthermore, the first layer <NUM> is configured to absorb and dampen the sound. In an embodiment, the first layer 20a comprises material that is resistant to wear and permeable to air, i.e. breathing. In an embodiment, the first layer 20a comprises material such as felt, foam rubber, polyester fibre, glass wool, rock wool, mineral wool or a combination thereof. In an embodiment, the density of the first layer 20a is between <NUM> and <NUM>/m<NUM> and preferably between <NUM> and <NUM>/m<NUM>.

<FIG> shows a further schematic view of a cross section of a wall structure <NUM> according to an example not belonging to the invention. The frame elements <NUM>, the support elements <NUM>,<NUM> and the first to third and sixth layers 20a-<NUM>,<NUM> have a structure as hereinbefore described with reference to <FIG>. The second damping element of the wall structure <NUM> comprises a fourth, outer damping, layer <NUM>' configured to provide for the acoustic and soundproofing effect and extending from the third layer to the sixth layer, i.e. there is no air gap <NUM> (<FIG>) between the fourth layer <NUM>' and the sixth layer <NUM>.

The fourth layer <NUM>' comprises porous or open cell material and is configured to absorb and dampen the sound. In an embodiment, the fourth layer <NUM>' comprises material such as felt, foam rubber, polyester fibre, glass wool, rock wool, mineral wool or a combination thereof. In an embodiment, the density of the fourth layer 40b is between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably of about <NUM>/m<NUM>.

<FIG> shows a further schematic view of a cross section of a wall structure <NUM> according to an embodiment of the invention. The frame elements <NUM>, the support elements <NUM>,<NUM> and the first to sixth layers 20a-<NUM> have a structure as hereinbefore described with reference to <FIG>. The first damping element A of the wall structure <NUM> further comprises a further layer, or second inner damping layer, 20c between the first 20a and the second 20b layers configured to provide for the acoustic and soundproofing effect.

The further layer 20c comprises porous or open cell material and is configured to absorb and dampen the sound. In an embodiment, the further layer 20c comprises material such as felt, foam rubber, polyester fibre, glass wool, rock wool, mineral wool or a combination thereof. In an embodiment, the density of the further layer 20c is between <NUM> and <NUM>/m<NUM>, preferably between <NUM> and <NUM>/m<NUM> and most preferably of about <NUM>/m<NUM>.

A skilled person understands that features of the embodiments described hereinbefore with reference to <FIG> and <FIG> are combined into further embodiments of the invention, not shown in the figures. Furthermore, the skilled person appreciates that the first B and/or second D stopping element of the wall structure <NUM>,<NUM>,<NUM>,<NUM> in a further embodiment comprises several layers instead of the single one described hereinbefore. For example the third layer <NUM>, e.g. a steel plate, of the first stopping element in an embodiment comprises a laminate structure with several layers.

Furthermore, the skilled person understands that the use of wall structure hereinbefore described is not limited to vertical walls, but is readily applicable for example to use in horizontal structures such as roofs or floors.

<FIG> shows a flow chart of a method of manufacturing a wall structure according to an embodiment of the invention. At step <NUM> the frame elements <NUM> are provided. At step <NUM>, the elements (A-D) with the layers 20a-<NUM> are attached in a conventional manner.

Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is providing a compact soundproof structure for a compact space. Another technical effect of one or more of the example embodiments disclosed herein is providing an improved soundproofing of a wall. Another technical effect of one or more of the example embodiments disclosed herein is improved acoustics of a compact space without sacrificing soundproofness.

Claim 1:
A wall structure, comprising the following elements in the following order:
a first dampening element (A) comprising at least one layer (<NUM>,20a-c) configured to form an acoustic inner surface and to dampen sound; followed by
a first stopping element (B) comprising at least one layer (<NUM>) configured to stop sound;
a second dampening element (C) comprising at least one layer (<NUM>,<NUM>',<NUM>) configured to dampen sound;
an air gap, and
a second stopping element (D) comprising at least one layer (<NUM>) configured to stop sound; wherein
the layers of the first (A) and second (C) dampening elements comprise porous and/or open cell material, wherein the second dampening element (C) comprises a fourth layer (<NUM>) comprising porous or open cell material;
wherein the air gap is configured to form together with the fourth layer a dampened air gap in order to dampen sound.