The subject of the utility model is a decorative wall mounted acoustic structure for use in construction, particularly as a wall-mounted finishing element in rooms. The invented product according to the utility model has a form of modular plates joined to a wall being finished with the use of an innovative frame. The function of the sound-insulating structure according to the design is to improve the acoustic properties and sound-insulate interiors of large rooms while keeping the high aesthetic level and simple construction.

State of the art

Within the state of the art basically two types of structures for sound- insulating of rooms and improvement of acoustic parameters of large facilities are used. The first type of various types of panels is based on the phenomenon of dissipation of the sound wave and this type of structure is referred to as a diffuser. Inventions of this type are based on the use of uneven texture of the dissipating surface in the form of various bosses, on which sound wave diffraction occurs. The second type of structures improving sound insulation properties called an absorber and it is based on the process of absorbing the energy of sound waves by a sound-absorbing material. Absorbing systems are usually based on the use of one or more layers of textile materials or other porous structures. In the world there are also available panels made mainly of mineral wool and glass wool and those are in turn obtained from magma rock and quartz sand deposits, which are non-recoverable. Additionally, it can be noted that veneered panels (3mm thick layer of wood) available on the markets are 100% absorbers or 100% diffusers. After an even deeper investigation, one can find wooden decorative panels with no sound-insulating properties.

The Polish utility model of PL68326 reveals a decorative sound-insulating panel formed by aluminum profiles in the form of plates which have a acoustically active surface that is bent into regular folds, and particularly with multiple folds or corrugations.

The American patent description of US6244378 reveals a composite panel with several layers which also functions as a diffuser and absorber of sound. The mentioned invention reveals a panel with several layers, where the first layer has a form of a honeycomb provided with openings and the next layer forms a Helmholtz resonator. The invention also reveals the use, as an alternative to corrugated surfaces, pyramidal structures in the form of pyramids (uniform and non-uniform) with a truncated apex. At the same time, individual pyramids after projection on the plane in the XY coordinate system have non -uniformly spaced apexes.

An inconvenience of the known solution is a high level of complexity, high weight of sound- insulating elements and questionable aesthetic qualities. The above-mentioned inconveniences are solved by the acoustic panel according to this model.

Essence of the solution

An sound-insulating system according to the model combines two functionalities in one modular, hybrid structure, which both dissipates and absorbs sounds. Combination of the of the geometrical diffuser and absorber of sound in one acoustic system results in a higher dissipation coefficient and sound absorption at the same time. Dissipation of sound results from the specific formation of the front face of panels, which breaks the sound waves to improve sound comfort, reduce reverberation and create an impression of depth. In effect, this implicates user's impression that the room provided with the system is larger than in reality. Improvement of the coefficient of sound absorption is obtained in two ways. Firstly, thanks to the use of dilatation gaps with specific width between the panels, specific construction of the distancing frame by the optimum distance and filling the space between the panels and the walls with sound-insulating material. Secondly, absorption of the energy of sound waves takes place also thanks to the panel, the front face of which takes the energy of sound waves and resonates thanks to the specific way of fixing to the frame and texture of the front face. This results in significant increase of the absorption coefficient, which implicates perceptible reduction of the noise level in the room.

The sound-insulating system according to the model consists of two groups of elements. The first one is a sound-insulating panel in a form of a wooden spatial (three-dimensional) plate with uneven, irregularly folded front face provided with formed pyramids with a step-changing angle of wall inclination. Smooth folding of the panel surface covers the arches and cavities. Depth of the folds can reach up to 60-80% of panel thickness. A single pyramid resembles two pyramids stacked one on the other with a different angle of wall inclination. While the base pyramid has a truncated apex, in place of which the other smaller pyramid with a different base surface area and different angle of wall inclination is set. The step-changing angle of wall inclination in pyramids being preferably 30° and 40° allows double and single reflections of sound waves, which in turn improves the effectiveness of sound dissipation.

The base surface area and height of individual pyramids is preferably different. The changing dimensions and shapes of individual pyramids improves the effectiveness of dissipation of sound waves of the system. The rear wall of the panel is provided with stress-relieving grooves ensuring reduction of stress of a panel, especially one made of wood or wood-derivative materials. This type of dilatation ensures more uniform work of the panel under the impact of moisture and stress. Thanks to those grooves, stress is distributed in the panel in a more uniform way and the panel does not get deformed. There are 3-7 mm dilatation gaps between individual panels. Behavior of the dilatation gaps between the panels with defined, specific width is important due to the fact that they function similarly to a Helmholtz resonator. The sound wave forcing through the dilatation gaps between the panels loses its energy, thus the sound pressure in the room is reduced.

A metal frame mounted on the walls functions as a rack positioned between the surface being finished and the rear face of the panel. The panels which may differ in formation of folds and size and shapes of the pyramids are hanged on the frame. Between the wall to which the panel is fixed and the rear panel face there is a gap that is preferably 50 mm filled with cubical elements made of the sound- insulating material, preferably glass wool. Keeping the distance of 50 mm from the rear panel face to the wall face allows absorption of waves at medium and low frequencies at approx. 1/4 of their length.

The system according to the model works so that the sound waves at high frequencies are dissipated by the texture and folded front face of the panel. While the sound waves at medium and low frequencies are absorbed thanks to dilatation gaps, sound-insulating materials filling the space behind the panel and resonance of the front face of the panel.

Elements of the sound-insulating material fill the free space between the rear side of the panel and the wall, as well as between the vertical and horizontal elements of the frame. The frame, thanks to its construction, functions as an absorber of sound waves. The basis of the frame is made by open or half-open profiles fixed vertically to the wall and directed with their open side to towards the surface of mounting. Vertical profiles are fixed to the wall with the use of well-known fittings, such as bolts or anchors. Those profiles are provided with slanted notches (keyways) in which horizontal mounting angle bars are inserted. The angle bar connected with the vertical profile is turned by 45° and blocked in a position resembling the letter "V". The angle bars are provided with horizontal slots located in the lower part of the angle bar close to the longitudinal axis, used for fixing the hangers. The angle bars can be extended by joining several sections with the use of bolts passing through the overlapped sections of two angle bars or with the use of additional link elements. The panels are hanged on the horizontal angle bars and to the rear face of the panels there are profiled hooking hangers with a cross-section resembling the number " 1 " attached. Each of the hanger plates is provided with a tongue, which is inserted into the slot in the horizontal bar to stabilize the position of the panel and preventing its movement or fall.

The wall-mounted sound-insulating system according to the model is characterized by a modular structure, the basic unit of which is a set of four panels and three vertical profiles, four horizontal angle bars and sixteen hooked hangers, as well as a set of pyramidal elements of the sound-insulating material made of glass wool. An exemplary, described basic module has dimensions of 2m x 2m. Each panel is hanged on two parallel horizontal angle bars. The horizontal bars are attached to the vertical profiles in pairs with the vertical spacing of 700 mm kept. While the distance between the lower bar of the upper pair and the upper bar of the lower pair is 300 mm.

The system according to this utility model does not require installation on the entire surface of the wall, for improvement of sound-insulating properties it is sufficient to cover only a section of the wall surface. While the increase of effectiveness of sound-insulation of the system is proportional to the coverage of installation of the system on the surface area of walls.

Filling with sound-insulating material elements between the panel and the wall prevents uncontrolled reflection of sound waves behind the panels. Additionally, the use of glass wool as an exemplary sound-insulating material and fire impregnation of the panel with the use of substance such as liquid glass improves the fire resistance of the entire system.

Illustration

The utility model has been presented in an embodiment on a drawing, where:

- fig.l presents the module of the system consisting of four panels in an isometric exploded view from the front side; - fig.2 presents the module of the system consisting of four panels in an isometric exploded view from the rear side (wall side);

- fig.3 presents the frame with an attached one panel in an isometric exploded view from the front side;

- fig.4 presents a single panel together with the hangers and sound-insulating elements in an isometric exploded view from the rear side (wall side);

- fig.5 presents an isometric exploded view of the frame elements ;

- fig.6a presents the panel in a version with three bulges in a three- dimensional view;

- fig.6a presents the panel in a version with three bulges in a front view;

- fig.7a presents the panel in a version with two bulges in a three-dimensional view;

- fig.7a presents the panel in a version with two bulges in a front view;

- fig.8a presents the panel, hanger, angle bar and profile in a view from top;

- fig.8b presents the panel, hanger, angle bar and profile in a view from side;

- fig.9a presents the panel grid in a version with three bulges in a front view;

- fig.9b presents the panel grid in a version with two bulges in a front view;

Embodiment

The wall-mounted sound-insulating system according to the utility model consists of four wooden panels 1 made of beech plywood with varying linearly folded front face covered on the whole area with pyramids 2 with varying base surface area and height. Dimensions of an exemplary panel 1 are 995mm x 995mm x 40mm (thickness) and the weight is 14.5 kg. The wall of each of the pyramids 2 has a step-changing angle of inclination, which is 30° and 40°. The area of folding covers approx. 3/4 of thickness of panel 1. The rear of each of the panels 1 is provided with stress-relieving grooves 3 that reduce the stress of the panel 1. Optionally, for easier installation of hangers 4 on the rear face of the panel 1 there are marked plates 5 to which hangers 4 are bolted. Between panels 1 there are dilatation gaps 6 with the width of 5mm. Panels 1 are hanged on horizontal angle bars 7 provided with slots 8 located at the edge of bending of bar 7. The distance of the rear face of panel 1 from the wall is 50 mm. Bars 7 close to the ends are provided with openings 9 used for installation of bolts or elements joining individual bars 7 with each other. Each of the panels 1 is hanged on two horizontal angle bars 7 with the use of four metal hangers 4 with a hooked shape provided on ends with a tongue 10 inserted into slot 8 in bar 7 and blocking in the position of panel 1. The hangers 4 are attached to the panel 1 with the use of bolts 11 or screws tightened close the corners of panel 1. The horizontal bars 7 are fixed to the vertical profiles 12 by catching the bar 7 directly into slanted cam key ways 13 in the vertical profiles 12 and turned by 45° in the horizontal axis. The keyways 13 are formed so that the horizontal angle bar 7 after catching is blocked inside the vertical profile 12. The vertical profiles 12 are fixed to the wall with the use of anchors 14. The free space between the wall and panel 1 and between the horizontal bars 7 and the vertical profiles 12 is tightly filled with pyramidal sound-insulating elements 15 made of glass wool. The panels 1 are preferably impregnated with a non-flammable substance based on boron.

Advantages (usability)

The wall-mounted sound-insulating system according to the utility model has two functions as a diffuser and absorber of sound, ensuring this way a higher level of acoustic comfort. Additionally, thanks to the specific construction of the frame and jointing the frame with individual elements, compensation of wall unevenness is possible. The specific formation of the front face of the panels not only improves the sound-insulating properties, but also allows installation of panels in any position. The panels can be turned in any direction by 90° and they are fixed to the frame in this way. Additionally to the two existing utility models of panels with various grids of folds (arches and cavities), there are many options of panel configurations, which ensures high variations of the surfaces of the entire system. The performed analyses indicate that the system according to the utility model presents the optimum effectiveness of absorption with relation to sound waves at the frequency of 2000Hz to 10000Hz.

The system according to the utility model is characterized with a high coefficient of sound absorption and insulation, thanks to which it ensures a more distinct sound without reverberation in large rooms, which results in improved communication and makes it unnecessary to raise the voice. The improvement of acoustic properties of rooms thanks to the use of a hybrid system according to the utility model contributes to reduction of stress, better concentration of children and personnel, and, as a consequence, lower impact of sounds on deterioration and loss of hearing abilities of persons occupying these rooms.

An advantage of decorative sound-insulating panels which constitute the visible part of the utility model is also observed in the use of a form that is visually different than that of available flat solutions with perforation. The use of a spatial form (3D) contributes to multi-sense perception and will improve the aesthetic qualities of the interiors. The system, as a part of the environment is perceived with various senses, through the three-dimensional structure, color, texture, acoustic properties. The look of the panels ensures a more varying sensual perception, by breaking the monotony of rooms in offices, schools, hospitals, this way improving the comfort of occupation and work. An advantage of the design presented by the utility model is creating a spatial form, which by reflection of light is a varying form depending on the time of day and angle of light. Changes in color intensity contributes in turn to the mental comfort of persons occupying a given environment.