GB2464318A

GB2464318A - Sound proofing furniture

Info

Publication number: GB2464318A
Application number: GB0818685A
Authority: GB
Inventors: Nick Turner
Original assignee: SCREENS AT WORK Ltd
Current assignee: SCREENS AT WORK Ltd
Priority date: 2008-10-11
Filing date: 2008-10-11
Publication date: 2010-04-14
Anticipated expiration: 2028-10-11
Also published as: GB0818685D0; GB2464318B

Abstract

Furniture comprises a cushioning material comprising a furniture foam 12 and a sound absorbing material 14, the cushioning material being covered with a non-membranous material 16 which permits the passage sound waves therethrough. The sound absorbing material may comprise a second foam, for example an open weave material.

Description

Improvements in and relating to furniture

BACKGROUND

a. Field of the Invention

The present invention relates to improvements in and relating to furniture, an improved material for use in the construction of an item of furniture and to a method of constructing an item of furniture. In particular, the present invention relates to sound absorbing items of furniture.

b. Related Art Open plan offices can provide an environment to encourage teamwork and communication within workplaces. However, such open plan offices can be distracting and noisy. Within open plan environments, people wanting privacy may require private rooms to make conference calls or to find a working area with relatively low noise and these disadvantages diminish the advantages of providing an open plan office. However, people working in isolation in private rooms discourage teamwork and reduces and inhibits communication between workers.

Open plan offices may include screens comprising sound absorbing material which aim to reduce workplace noises. However, whilst screens are effective, one aim of the present invention is to increase the effectiveness of reducing noise, especially in working environments and, in particular, open plan working environments. Furthermore, the effectiveness of noise reduction is increased if the noise can be absorbed as close to the source of the noise as possible. This reduces and inhibits the opportunities for the noise to reverberate and to be dispersed over a wide area which may result in the noise becoming difficult to be contained and/or absorbed. In an office environment, the furniture and surrounding screens are generally located the closest to the worker and the walls and ceilings are generally relatively distant from the worker.

It is an aim of the present invention to overcome at least one problem associated the prior art either referred to herein or otherwise.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided an item of furniture comprising a cushioning material comprising a first foam comprising a furniture foam and a sound absorbing material, the cushioning material being covered with a non-membranous material.

Preferably the non-membranous material does not provide a sound reflecting surface and enables a significant proportion of sound waves to travel therethrough.

Preferably the non-membranous material encourages and enables the majority of sound waves to travel therethrough with only a minority of sound waves being reflected by the surface of the material.

Preferably the sound absorbing material comprises a second foam.

Preferably the cushioning material is covered with a breathable material.

Preferably the cushioning material is covered with a non-continuous material.

Preferably the non-membranous material comprises an open weave material.

Preferably the cushioning material is covered with a material which facilitates the penetration of sound waves into the cushioning material.

Preferably the sound absorbing material comprises a sound absorbing foam.

The sound absorbing foam may comprise a substantially brittle foam.

Preferably the sound absorbing foam comprises an acoustic foam.

Preferably the sound absorbing foam comprises lamaphon foam.

The sound absorbing foam may comprise a melamine resin foam.

Preferably the first foam comprises a sound absorption co-efficient and the second foam has second sound absorption co-efficient wherein the second sound absorption co-efficient is greater than the first sound absorption co-efficient.

Preferably the furniture foam comprises a flexible foam and more preferably a flexible polyurethane foam.

The cushioning material may be a laminar including an outer layer of an open weave material, at least a first layer of a furniture foam, and a layer of sound absorbing foam.

The cushioning material may comprise two layers of furniture foam which may be located adjacent to both planar sides of the sound absorption foam.

Preferably the item of furniture comprises a reinforcing member. Preferably the reinforcing member provides the cushioning material with a predetermined profile.

Preferably the reinforcing member comprises a substantially rigid planar member.

The reinforcing member may comprise plywood and preferably comprises a shaped plywood member.

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The reinforcing member provides the cushioning material with a sound reflecting surface which is arranged to reflect a portion of the sound waves that pass through the sound absorbing foam back through the sound absorbing foam in order to increase the amount of sound absorbed. This may effectively double the distance that the sound waves must travel through the sound absorbing foam.

Preferably the item of furniture comprises an office based item of furniture.

According to a second aspect of the present invention, there is provided a cushioning material for use in an item of furniture, the cushioning material comprising a first foam comprising a furniture foam and a second foam comprising a sound absorbing material, the cushioning material being covered by a non-membranous material.

According to a third aspect of the present invention there is provided a method of constructing an item of furniture comprising locating a furniture foam adjacent to a sound absorbing material and providing a covering of a non-membranous material.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example only, with reference to the drawings that follow, in which: Figure 1 is a cross-section of a preferred embodiment of a cushioning material for use in an item of furniture.

Figure 2 is a cross-section of an item of furniture including a preferred embodiment of a cushioning material.

Figure 3 is a cross-section of part of an item of furniture including an alternative embodiment of a cushioning material.

Figure 4 is a front view of an embodiment of an office chair including an embodiment of a cushioning material.

Figure 5 is a side view of an embodiment of an office chair including an embodiment of a cushioning material.

Figure 6 is a rear view of an embodiment of an office chair including an embodiment of a cushioning material.

DETAILED DESCRIPTION

An item of furniture generally comprises a cushioning material comprising a furniture foam which provides the comfort required for the item of furniture.

Furniture foam generally comprises a flexible polyurethane foam which is selected to provide the comfort required. In particular, the density of the furniture foam affects the foam's ability to provide support, comfort and durability. The durability of the foam generally increases as the density of the foam increases. The durability of the foam relates to the loss of firmness (flexible fatigue), breakdown in the sitting area of the cushion (dishing), and fabric bagging caused by loss of foam dimensions (compression set). The indentation force deflection (lED) is a measure of the foam firmness that is independent of density and, for example, high density foam can be soft. A further property of furniture foam is the compression modulus (support factor). This is primarily a property of the type of foam. The compression modulus effects cradling" and for greater comfort the compression modulus may be selected to maximise "cradling". Foam with a relatively low compression modulus may be used with thick cushions to improve cradling and to achieve a more even distribution of body weight. Foam with a relatively high compression modulus may be used to prevent "bottoming" and/or "hammocking" of the seating area.

The durability of furniture foam is an indication of the foam's long term ability to provide the required cradling and support. A foam with a relatively high flex fatigue value will retain its original firmness and support level which means that the foam will retain its original characteristics.

A further factor which is essential for furniture foam is the resilience. The resilience of a furniture foam affects the comfort and design of the item of furniture.

For example, furniture foam with a high resilience feels springy.

As described above, furniture foam has specific characteristics which are carefully selected and adjusted depending upon the nature and use of the furniture foam.

However, sound absorbing foam has anumber of characteristics which mean that sound absorbing foam with a relatively high sound absorption co-efficient are not suitable for use as furniture foam or upholstery foam. In particular, sound absorbing foam is generally brittle and provides a substantially rigid (i.e. not substantially resilient) structure unlike the resilient structure provided by furniture foam. The sound absorbing foam provides a rigid porous structure which includes a plurality of pores to allow sound waves entering to be dissipated. In effect, the energy of the sound waves is converted into heat energy and is dissipated. In such a rigid porous material, the sound waves continuously collide against the surfaces of the porous portions.

The present invention provides an item of furniture including the required furniture foam properties whilst also providing the sound absorption characteristics of a specialist sound absorbing foam. Previously, the sound absorbing characteristics of upholstery foam have been accepted and the problem of excess noise has been addressed by fitting addition and supplementary sound absorbing panels to the walls or filing cabinets etc. This therefore requires additional fixations and the addition of sound absorbing panels may be bulky and may not be possible in some situations where space is not available.

As shown in Figure 1, a cushioning material (or upholstery material) 10 comprises a laminated material including an outer layer of an open weave fabric 16 and at least one layer of a furniture foam 12 and at least one layer of a specific sound absorbing foam 14. Accordingly, the furniture foam 12 is able to provide the desired characteristics of the item of furniture 20. The thickness of the layer of furniture foam 12 will need to be less than the standard thickness of furniture foam for a conventional item of furniture which does not incorporate sound absorbing properties. Accordingly, the properties and characteristics of the furniture foam 12 may be different from the conventional furniture foam selected previously. The cushioning material includes a substantially rigid reinforcing sheet (not shown) to provide the shape and contours required by the cushioning material.

The layer of the furniture foam 12 is arranged to locate adjacent to the support surface/area of the item of furniture 20 such that the comfort and support for. user will be primarily achieved through the characteristics of the furniture foam 12 rather than the sound absorbing foam 14. The layer of the sound absorbing foam 14 is, therefore, located at the rear of the support area or adjacent the base of the support area, as shown in Figure 2. The item o f furniture may comprise a convention office type chair 20 having the standard metallic/rigid stand 18 which does not absorb sound but provides both a seating support area and a backrest area that are both arranged to specifically absorb sound whilst also providing the required support and comfort characteristics of an office chair.

In another embodiment of the present invention, the cushioning material comprises a first layer of furniture foam 12 and a second layer of furniture foam 12 with a layer of sound absorbing foam 14 located therebetween, as shown in Figure 3. This configuration may be particularly beneficial and advantageous where the material is used to provide two support areas on opposite planar faces for the item of furniture or where the material (for example, a cushion) is reversible.

In the preferred embodiment, the sound absorbing foam 14 comprises a Lamaphon M' Series Foam. The sound absorbing foam 14 is a melamine resin type foam and has a density of 8-1 1 kgm3.

The furniture foam comprises a standard furniture foam and comprises a flexible polyurethane foam.

The sound absorbing foam 14 meets the fire performance standards for upholstery and furniture foam and is in accordance with Class 0' Building Regulations.

The thickness of the sound absorbing foam 14 can be selected depending upon the requirements of both the item of furniture and the environment in which the item of furniture is intended.

In particular, the acoustic performance of the sound absorbing foam provides a noise reduction coefficient (NRC) of 0.60 to ASTM C 423-90a in a 25 mm thickness. More particularly, the acoustic performance is as follows: Foam thickness Sound absorption Coefficient (Practical Absorption Coefficients to EN ISO 11654:1997.) Hz 250 Hz 500 Hz 1000 Hz 2000 Hz 4000 Hz 12mm 0.05 0.10 0.25 0.50 0.65 0.75 mm 0.10 0.20 0.50 0.80 0.85 0.95 50mm 0.15 0.50 0.90 1.05 1.10 1.05 The sound absorbing foam 14 is adhered to the furniture foam 12 with suitable adhesive means. Alternatively, the sound absorbing foam 14 may simply be retained adjacent to the furniture foam 12.

The cushioning material is enclosed or covered by a layer of an open weave fabric 16 or material. The open weave fabric 16 enhances the sound absorbing properties of the cushioning material 10. In particular, the open weave fabric 16 prevents or inhibits the reflection of sound and noise and aids the penetration of the sound/noise towards the sound absorbing material 14. In particular, the material does not provide a sound reflecting membrane but encourages the sound waves to penetrate into the cushioning material. Covering such as leather or vinyl effectively provide a sound reflecting membrane and prevents or inhibits the penetration of sound waves therethrough. -9-.

Standard upholstery foams are normally polyurethane/ether based open cell products, which are designed to be resilient against continuous compression, The advantages of a Lamaphon foam are its acoustic properties, fire resistance and its longevity. The Lamaphon foam is designed to optimize absorption across the frequency range which can be enhanced by combining other acoustic products. Its fire resistant properties are also superior to standard upholstery foams. The Lamaphon product offers BS476 Class "o" fire classification as well as other European classifications. Many polyurethane/ether foams degrade and collapse over time, the Lamaphon foam has a "Melamirie" content which ensures longevity after polyurethane/ether foams have been reduced to dust.

Lamaphon foam is not suitable for use as a seating cushion.

In alternative embodiments, Lamapro M' Series acoustic foam and/or Lamacell reduction laminate may be used. This is a flexible lightweight acoustic foam with a fine open cell structure offering excellent sound absorbing qualities, with high compressive strength.

The Lamapro "M" Series is an ideal component for sound absorbing or resilient spacing layer. The combination of the bespoke composite material offers both absorption and sound reduction properties.

In one embodiment, an office chair 40 generally resembles a conventional office chair, as shown in Figure 4, Figure 5 and Figure 6. However, the office chair 40 is provided with an enlarged headrest 42 to maximise and increase the sound absorbing properties of the chair 40. In particular, the rear face of the headrest 42 is at a good position and height to be either close to the source of the sounds (e.g. the mouth of a standing colleague) to quickly commence absorption and/or at a good location to absorb sound close to the detection, i.e. the ears of the worker on the office chair 40.

The office chair 40 provides a conventional seat 45 and a backrest 44 which provide an area of a furniture foam 48 to provide the required resilience and -10-comfort for the user. Similarly, the headrest 42 includes a section of furniture foam 48 on its outer face.

The office chair 40 includes a rigid reinforcement member 50 in the form of a reinforcing plate which provides the backrest 44 with a predetermined shape and profile. The reinforcing plate 50 effectively provides contours and a shape required by the item of furniture 40. The reinforcement member 50 comprises a preformed shaped piece of plywood. The layer of furniture foam 48 locates adjacent to one face of the plywood sheet 50 whTlst the layer of sound absorbing foam 52 locates adjacent to the other face of the plywood sheet 50. The layers of foam 52, 48 may be bonded or otherwise adhered to the plywood sheet 50 or may be physically not joined/bonded to the plywood sheet 50. A layer of material may be provided between the layers of foam 52 and/or 48 and this may include a layer of a sound dissipating material. In particular, a layer of rubber may be provided over one or both faces of the plywood sheet 50 and this may help to dissipate the noise energy. A hard, rigid, smooth surface may usually reflect and transmit a significant proportion of the noise so this additional layer(s) may increase the effectiveness.

As shown in Figure 4, Figure 5 and Figure 6, the surface area provided by the rear of the office chair 40 is maximised to increase the sound absorbing properties of the office chair 40. Since most noise to be absorbed will approach the chair 40 from the rear, the sound waves will penetrate into the sound absorbing foam 52 and be partially absorbed. The remaining sound waves will then approach the plywood sheet 50 where a portion of the sound waves will be reflected whilst some will be absorbed by the plywood 50. The reflected sound waves must then travel back through the sound absorbing foam 52 where, again, a proportion of the sound waves will be absorbed. This effectively doubles the travel distance of the sound waves through the sound absorbing foam 52. It is appreciated that some sound waves may be reflected back out of the rear of the chair 40 and some may penetrate through the chair 40 although this will be significantly lower in comparison with a standard office chair. -11 -

Prior art conventional chairs may be provided with a backing of a relatively cheap conventional foam. This is relatively ineffective in reducing noise and is generally bulky.

Modern office environments may now include numerous rows of desks that are relatively tightly packed together in order to maximise the number of workers within a given area and to make the most out of the relatively expensive office space. These workers may work in booths created using screen and provide linear rows of working booths.

Environments may now be tested for the reverberation time which demonstrates the amount of time that Sound waves continue to reverberate within a given environment. For example, office environments prefer low reverberation times to maintain a relatively quiet atmosphere. However, it may be preferred to maintain a

certain level of background noise (white noise).

Survey services may measure the reverberation time in a room and assigning a value to that reverberation time. This value may be assigned on a points basis whereby other parameters may also be assigned a points value. For example, each item of furniture may be assigned a points value by which it will reduce the reverberation time within the room. For the present invention, the preferred embodiments of the present invention will have a relatively high value and, therefore, it may be relatively easy to reduce the reverberation time within a room by using the present invention instead of conventional items of furniture. For example, each sound absorbing office chair may equate to I point whilst a sound absorbing screen may equate to 2 points. If a room has a reverberation value of 2000 points and the acceptable value for the working environment is 1000 points, then if there are 300 workers within the environment then the reverberation value of the room may be reduced by 900 points if each of the 300 workers is provided with a sound absorbing office chair (1 point) and a sound absorbing screen (2 points). Conventional office mesh chairs may have a negligible value and replacing such chairs with sound absorbing chairs will significantly reduce the reverberation time within the environment. Further actions may also be taken to reduce the value to the acceptable or optimum level.

Claims

CLAIMS1. An item of furniture comprising a cushioning material comprising a first foam comprising a furniture foam and a sound absorbing material, the cushioning material being covered with a non-membranous material.
2. An item of furniture according to Claim I in which the non-membranous material does not provide a sound reflecting surface and enables a significant proportion of sound waves to travel therethrough.
3. An item of furniture according to Claim I or Claim 2 in which the non-membranous material encourages and enables the majority of sound waves to travel therethrough with only a minority of sound waves being reflected by the surface of the material.
4. An item of furniture according to any preceding claim in which the sound absorbing material comprises a second foam.
5. An item of furniture according to any preceding claim in which the cushioning material is covered with a breathable material.
6. An item of furniture according to any preceding claim in which the cushioning material is covered with a non-continuous material.
7. An item of furniture according to any preceding claim in which the non-membranous material comprises an open weave material.
8. An item of furniture according to any preceding claim in which the cushioning material is covered with a material which facilitates the penetration of sound waves into the cushioning material.
9. An item of furniture according to any preceding claim in which the sound -14 -absorbing material comprises a sound absorbing foam.
10. An item of furniture according to Claim 9 in which the sound absorbing foam comprises a substantially brittle foam.
11. An item of furniture according to any preceding claim in which the sound absorbing material comprises an acoustic foam.
12. An item of furniture according to any preceding claim in which the sound absorbing material comprises lamaphon foam.
13. An item of furniture according to any preceding claim in which the sound absorbing material comprises a melamine resin foam.
14. An item of furniture according to any preceding claim in which the first foam has a first sound absorption co-efficient and the sound absorbing material has a second sound absorption co-efficient wherein the second sound absorption co-efficient is greater than the first sound absorption co-efficient.
15. An item of furniture according to any preceding claim in which the furniture foam comprises a flexible polyurethane foam.
16. An item of furniture according to any preceding claim in which the cushioning material is a laminar including an outer layer of an open weave material, at least a first layer of a furniture foam, and a layer of sound absorbing material.
17. An item of furniture according to any preceding claim in which the cushioning material comprises two layers of furniture foam which may be located adjacent to both planar sides of the sound absorption foam.
18. An item of furniture according to any preceding claim in which the item of furniture comprises a reinforcing member.
19. An item of furniture according to Claim 18 in which the reinforcing member provides the cushioning material with a predetermined profile.
20. An item of furniture according to Claim 18 or Claim 19 in which the reinforcing member comprises a substantially rigid planar member.
21. An item of furniture according to any one of Claim 18 to Claim 20 in which the reinforcing member provides the cushioning material with a sound reflecting surface which is arranged to reflect a portion of the sound waves that pass through the sound absorbing material back through the sound absorbing material in order to increase the amount of sound absorbed
22. A cushioning material for use in an item of furniture) the cushioning material comprising a first foam comprising a furniture foam and a sound absorbing material, the cushioning material being covered by a non-membranous material.
23. A method of constructing an item of furniture comprising locating a furniture foam adjacent to a sound absorbing material and providing a covering of a non-rnembranous material.
24. An item of furniture substantially as herein described with reference to, and as shown in, any of the accompanying drawings.
25. A cushioning material for use in an item of furniture substantially as herein described with reference to, and as shown in, any of the accompanying drawings.
26. A method of constructing an item of furniture substantially as herein described with reference to, and as shown in, any of the accompanying drawings.