GB2428705A - A clip device for location between two surfaces to reduce acoustic coupling - Google Patents

Abstract

A device for location between two surfaces to reduce acoustic coupling, the device comprises a clip portion 20 and a bracket portion 30 having complimentary engagement means. Clip 20 comprises a channel shaped body having a substantially planar channel base portion 12, channel walls 14, "A" channel inter-engagement means 15 in the from of spring clips and resilient material 16, 16'. The resilient material 16' is located between the clip 20 and bracket 30 when assembled. The resilient material 16 is located between the clip and the web of an "I" stud when the clip is in use with an "I" stud or the surface of a wall or ceiling joist. Bracket 30 comprises a channel shaped body having a base portion 32, stud engagement portions 34 and resilient retention portions 36. The retention portions 36 abut the resilient material 16' thereby holding the clip 20 in place relative to the bracket by means of frictional forces. Also provided is a system incorporating such a device and a method of using such a device.

Description

CLIP DEVICE

Background to the invention

The present invention relates to a device (otherwise known as a floating clip), a system incorporating such a device and a method of use of such a device, for example, to provide high acoustic performance partition walls.

In England and Wales, Part E of the building regulations contains soundinsulation requirements for separating walls and separating floors and stairs. These requirements include: a. separating walls shall resist the transmission of airborne sound; and b. separating floors and stairs shall resist the transmission of airborne and impact sound.

These requirements apply to all new build and conversion dwellings.

Such building requirements are likely to either be in effect in other countries or have the potential for becoming requirements in other countries.

Normal construction methods used when Construction a partition wall use wood or metal. Normal construction methodology conventionally involves screwing plasterboard to each side of a stud frame consisting of a bottom rail, a top rail, and vertical rails positioned at 600 mm apart. When using meta', the bottom and top rails are typically referred to as the U channel tracks and the vertical rails are typically referred to as C section studs i.e. studs with a C'-shaped cross section, positioned at 400 mm or 600 mm intervals, the C section studs extending vertically and joining the top and bottom tracks.

A further metal stud arrangement uses studs which are I' or H' shaped in cross- section. Such studs are typically used when a stiffer partition construction is desired.

In principle, double leaf walls provide better sound insulation that single leaf walls as the sound waves encounter the two separate masses whose sound insulation could be added together. However, in practice, this would only occur if the two masses were completely isolated from one another. Effective isolation has proved difficult to achieve in domestic masonry walls. For example, a 280 mm plastered cavity brick wall is no better than a 280 mm plastered solid brick wall, because of the higher critical frequency in each leaf and the bridging effect of the ties between leaves. This phenomenon is known as acoustic coupling.

Lightweight forms of domestic construction owe much of their soundinsulation performance to isolation. This can be illustrated by considering two sheets of plasterboard, each giving 25 dB sound insulation at 55 Hz. If they are bonded together, the mass law prevails and a result of 30 dB is obtained. If it were possible to isolate then from one another, 50 dB would result.

In practice, the isolation will not be perfect as it depend upon: a. the method of fixing (mechanical coupling) i.e. how rigidly the two leaves are attached together; and b. acoustic coupling, which is affected by the width of the gap between the leaves and whether there is an acoustic absorber in the cavity, such as mineral wool or the like.

In order for two surfaces to move independently from one another (thereby minimising mechanical coupling), the two surfaces must be disconnected from one another such that when the sound pressure wave hits the first surface and causes it to move much like a diaphragm, its influence on the second surface (say of a partition wall) is not like a compiled spring. It will move, but not necessarily in synchronisation.

In addition to isolation, there is flanking transmission. There are several reasons for flanking transmission, such as gaps or holes, mechanical bridging, acoustic coupling of two leaves, and incorrect bonding between wall and floor/ceiling.

There is therefore a need in the prior art for a means to reduce the undesirable effect mentioned above in order to improve sound insulation performance.

Summary of the Invention

The present invention seeks to address the problems of the prior art.

Accordingly, a first aspect of the present invention provides a device for location between two surfaces to reduce acoustic coupling therebetween, the device comprising: a. a clip portion having a body defining a stud engagement portion and a first engagement portion; b. a bracket portion having a body defining a second engagement portion complementary to the first engagement portion; c. a first resilient member at least a portion of which is located between the first and second engagement portions; and d. a second resilient member provided on at least a portion of the stud engagement portion.

The two resilient members may comprise the same or different materials. Each resilient member may comprise any one or more of materials such as, but not limited to closed cell foam, open cell foam or rubber. It will be appreciated that any other suitable material known to the skilled person could be used alone as an alternative to the aforementioned materials or may be used in combination with any one or more of the aforementioned materials.

A particularly suitable closed cell foam would be one having a density falling within the range of 30 kg/rn3 to 110 kg/rn3.

A particularly suitable open cell foam would be one having a density falling within the range of 30 kg/rn3 and 200 kg/rn3.

In one embodiment, the second engagement portion comprises a channel defined by the bracket portion body.

The bracket portion may further comprise a retention member for retaining the first and second engagement portions in complementary interengagement with one another.

The retention member may comprise one or more projections extending from the bracket portion body which abut against the resilient member located between the bracket portion and clip portion when the first and second engagement portions are engaged with one another so as to retain the clip portion and bracket portion together by means of a frictional fit.

It will be appreciated that the retention member may be provided on the clip body rather than the bracket body as an alternative. In addition, it will be appreciated that any other suitable retention means known to the skilled person may be employed to hold the bracket body and clip body in engagement with one another, whether by frictional forces, magnetic forces, bonding forces, or any other suitable fastening manner.

S

In one embodiment, the first engagement portion is received within the channel of the bracket body.

In a further embodiment, the bracket portion is further provided with stud engagement means.

In a further embodiment, the clip portion further comprises A' channel engagement means. For example, the clip body may further define a channel, the walls of the channel defining the A' channel engagement means.

In one embodiment, the walls of the clip body comprise opposing projections forming a spring clip arrangement for complementary interengagement with the A' channel.

A further aspect of the present invention provides a system for reducing acoustic coupling between two surfaces, the system comprising: a. a first substantially planar surface; b. a plurality of devices in accordance with any one of Claims I to 9, coupled to the first surface; c. a plurality of A' channels, each A' channel coupled to a device; and d. a second substantially planar surface coupled to the plurality of'A' channels, such that the two surfaces are substantially parallel to one another.

The first surface may comprise a wall. Alternatively, the first surface may comprises a stud frame coupled to a partition wall. A further alternative is that the first surface comprises a ceiling joist arrangement.

The present invention makes use of the various stud formats available within the building industry and readily obtainable from builder's merchants, but allows them to be used in conjunction with isolation brackets and devices in accordance with a first aspect of the present invention. It is the device in accordance with a first aspect of the present invention which provides the separation of the two leaves or surfaces of a partition wall. The device provides the same degree of isolation for a ceiling when a second drop ceiling is fixed to an existing ceiling. Often in the case of ceilings, room height is very important. The present invention allows the floor and existing ceiling to move independently from the second drop ceiling with the minimum of loss in room height.

A further aspect of the present invention provides a method of production of an acoustically decoupled partition wall arrangement comprising the steps of: a. providing an upper rail and a second substantially parallel lower rail; b. providing a plurality of spatially separated substantially parallel vertical rails and coupling the substantially vertical rails to the upper and lower rails in an acoustically isolated manner; c. providing a plurality of devices in accordance with any one of Claims 1 to 9 and coupling the devices to two opposing surfaces of the substantially vertical rails such that the devices extend away from the vertical rails in a direction perpendicular to the elongate axis through the substantially vertical rails; d. providing a plurality of A' channels and coupling each A' channel to a corresponding device such that each A' channel extends between the upper and lower rails; and e. providing tow partition walls and coupling a partition wall to each of the opposing surfaces of the substantially vertical rails by means of the A' channels such that each partition wall is substantially parallel to the other with the rails, devices and A' channels located therebetween.

The present invention provides a damper to both surfaces of a lightweight partition wall. The significant damping of the surfaces ensures that the effect of the critical frequency is removed. In addition, any movement of one surface will not be in synchronisation with the second surface. This means that at some time intervals, the movement of the two surfaces will be in opposite directions so cancelling each other out.

Another benefit of the present invention is the reduction in sound that travels along any element common to both sides of a partition wall, known as flanking transmission. Flanking transmission can equal or even exceed direct transmission and degrade the overall sound insulation result. The present invention reduces the effect of mechanical bridging, such as the unwanted connections when two surfaces of a stud partition wall are screwfixed to a metal or wood stud where the stud provides rigid coupling.

Brief Description of the Drawings

An embodiment of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a side view of an embodiment of a clip and bracket (and resilient member) arrangement in accordance with a first aspect of the present invention shown in a disassembled state; Figure IA is a perspective view of the clip of the embodiment of figure 1 (shown without the resilient member); Figure lB and figure 1C are perspective and plan views, respectively, of the bracket of the embodiment of figure 1; Figure 2 is a side view of the embodiment of figure 1 shown in an assembled state, together with an A' channel; Figure 2A is a side view of the embodiment of figure 1 shown coupled to an I' stud; Figure 3 illustrates a plan view and end view of an isolation bracket with and without an acoustic isolation membrane in position; and Figure 4 is a side view of an isolation bracket in position with a C' channel and I' stud arrangement.

Detailed Description of the Invention

Figures 1A to D, 2, and 2A show a two part clip 10, now referred to as a floating clip 10. The example shown in the figures is made out of sprung steel. However, it will be appreciated that any suitably strong and resilient material known to the skilled person could be used in combination with sprung steel or as an alternative to sprung steel.

Floating clip 10 comprises a clip 20 and a bracket 30 having complementary inter- engagement means such that the clip 20 and bracket 30 may be engaged as shown in figure 2A.

Clip 20 comprises a channel shaped body having a substantially planar channel base portion 12, channel walls 14, A' channel inter-engagement means 15 in the form of sprung clips and is provided with resilient material 16, 16' on the upper and lower surfaces 18, I 8' of base 12.

The resilient material 16' provided on the lower surface 18' of base 12 is located between the clip 20 and bracket 30 when the floating clip 10 is assembled. The resilient material 16 provided on the upper surface 18 of base 12 is located between the floating clip 10 and the web of an I' stud when the floating clip 10 is in use with an I' stud, or the surface of a wall or ceiling joist where the new partition surface is to be constructed relative to an existing wall or as a floating ceiling, respectively.

Thus, assembled clip and bracket arrangement when in use comprises a floating clip 10 that isolates the A' channel 15 from the I' stud.

Bracket 30 comprises a channel shaped body having a substantially planar channel base portion 32, stud engagement portions 34, and resilient retention portions 36.

Retention portions 36 comprise projection members which extend outwards such that when the bracket 30 and clip 20 are engaged, the retention portions 36 abut the resilient material 16' provided on the lower surface 18' of clip 20, thereby holding the clip 20 in place relative to the bracket 30 by means of frictional forces.

In use, the bracket 30 and clip 20 would typically be supplied as a preassembled floating clip 10.

The floating clip 10 is universal in as much as it may be incorporated into the construction of partition walls using metal or wood or it can be fixed to walls and ceiling surfaces as will be described.

When incorporating the floating clip 10 in a metal stud wall construction, an I' stud is used for the vertical stud in combination with a U' channel 40 i.e. a track with a U' shaped cross-Section, for each of the top and bottom rails.

Following normal partition construction procedure with the top and bottom U' channels 40 fixed, the bottom U' channel 40 mounted on a wood sole plate bedded on an acoustic sealant, the I' stud 50 is fixed at 90 degrees to the' normal (see plan view in figure 4) so that the web 52 of the I' stud 50 extends in the direction of the U' channel.

The I' stud 50 is centred within the U' channel 40 using the track isolation bracket 60 (see figure 3). The web 52 of the I' stud 50 is then slipped between the three upturned tabs 62 of the isolation bracket 60. The isolation bracket 60 provides isolation between the U' channel 40 and the I' stud 50.

Having fixed the top and bottom U' channels 40 in place, the 1' studs 50 are then fixed in place at intervals of 400 mm along the U' channel 40 using the isolation bracket 60 at the top and bottom of the I' studs 50 to secure the I' studs 50. The metal stud frame 40, 50 is now ready to receive floating brackets 10 at 600 mm intervals along the length of each of the I' studs 50. This is repeated on both sides of the I' studs 50 which face outwards at a perpendicular angle relative to the longitudinal direction of the U' channels 40.

A' channels 15 are then cut to size so at to extend between the top lip of the bottom U' channel 40 and the underside lip of the top U' channel 40. A' channels 15 are then pushed into engagement with the A' channel interengagement means 16 of the floating clips 10 on both sides of the I' stud 40. It is important that the A' channels IS are a snug fit between the top and bottom U' channels 50 so as to prevent undesirable vertical movement of the A' channel, yet allowing sufficient clearance to accommodate a foam pad.

Finally, a first plasterboard surface is fixed to the A' channels 15 on one side of the I' channel 40, for example, using for example dry wall self tapping screws at 300 mm intervals. An acoustic insulation quilt is then inserted into the cavity and a second plasterboard surface fixed to the A' channels 1 5 on the opposing side of the I' channel 40 to the first plasterboard surface. Care should be taken to seal all joints with acoustic sealant.

This system allows the two surfaces (plasterboard on both sides) to move independently thereby providing a very high performance whilst preserving the maximum room footprint. The present invention reduces the level of low frequency noise that transmits through the common parts of a wall (curve transport). This is achieved by decoupling the common parts that make up the partition wall i.e. the I' stud 40 and U' channel 50.

The resilient material may comprise any suitable open or closed cell foam material, such as a closed cell foam material having a density falling within the range of 30 kg/rn3 to 110 kg/rn3 or an open cell foam material having a density falling within the range of 30 kg/rn3 to 200 kg/rn3.

The present invention provides a useful modification to conventional partition wall construction.

The principles adopted for the partition wall arrangement described above may also be applied to ceiling treatments, such as the installation of a floating ceiling. In most cases, wooden joists would be used. The same floating clip 10 as shown in figures 1, 2, and 2A would be secured to the undersides of wooden joists, in some cases through the existing finished ceiling, using wood screws.

The arrangement of the resilient retention portions 36 of the bracket 30 serves to protect the resilient layer from damage when inserting the clip 20 through the 10 mm by 36 mm holes in the metal bracket 30. Fixings should be at 600 mm intervals in line with the joists and the same distance apart as the joists, which is typically 400 mm.

After fixing the floating clips 10 to the joists, the A' channels 15 should be coupled to the floating clips 10. This will require the application of sufficient force to each A' channel to overcome the spring tension of the A' channel inter- engagement means 16 of the floating clips 10. An acoustic quilt should then be introduced adjacent the A' channels 15 and high density plasterboard fixed to the A' channels 15 using dry wall self tapping screws. For improved all round performance, a second layer of plasterboard should then be fixed to the first layer.

In this way, the floating clips 10 create a decoupled ceiling using a minimum of space by allowing the existing ceiling and floor arrangement to move due to both impact and airborne sound pressure waves independent of the new ceiling fixed to the floating bracket arrangement. A major advantage of such an arrangement is the provision of an effective acoustic solution from a room from below when the area above the room is not accessible.

Further use can be made of the bracket when using wood studs. The partition would be constructed in the same way as when using a metal stud, as described above, however, the floating bracket arrangement described above for the floating ceiling arrangement could be used. Unfortunately however, there would be no saving in wall thickness, but rather, the walls would be much thicker.

Where the present invention is of particular use is on existing party walls where the floating brackets can simply be fixed to the existing wall in vertical lines at 400 mm intervals apart in horizontally and at 600 mm intervals vertically. The A' channels 15 would then be coupled to the floating clips 10, an acoustic quilt inserted adjacent the A' channels 15 and high density plasterboard fitted to the A' channels using dry wall self tapping screws.

The floating brackets of the present invention may also be used on the internal face of a building envelope to reduce the ingress of sound from the external environment. This is of particular value to improve building sound performance in high noise environments. The floating clip used as a series of single units suitably spaced will improve the sound reduction acoustic performance of the building envelope when fixed to the inner wall face to carry a suitable stud to which is fixed a high density plasterboard. The arrangement reduces acoustic coupling and enhances dampening.

The present invention improves the overall sound insulation performance of walls and floors by introducing a damper and breaking the acoustic coupling that exists in all single stud walls and floors. By introducing a damper, the resonant frequency of the wall is moved outside the 100 Hz to 3500 Hz bandwidth, and by introducing a level of isolation, the flanking transmission is reduced through the common parts of the partition separating two room spaces. The major advantage of the present invention is to achieve the performance improvement within a 100 mm wall thickness thereby preserving the useable footprint i.e. the useable room area.

The floating clip discussed above when used alone ensures that the two leaves of a wooden frame partition wall can move independently when one or both leaves are subjected to sound pressure waves.

The installation of the floating clip and insulation bracket combination in a partition wall construction introduces a damping effect that improves low frequency sound reduction performance by moving the critical frequency.

The introduction of the floating clip and isolation clip removes the coincidence dip between 2000 Hz and 3140 Hz by preventing the leaves from reaching resonance within the 100 Hz to 3500 Hz bandwidth. It also reduces the acoustic coupling in the common parts of the partition wall, thereby reducing flanking transmission.

Finally, the floating clip of the present invention provides damping and isolation for internal noise levels arising from building services by suppressing tonal and impulsive characteristics.

Although aspects of the invention have been described with reference to the embodiment shown in the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiment shown and that various changes and modifications may be effected without further inventive skill and effort. is

Claims (22)

1. A device for location between two surfaces to reduce acoustic coupling therebetween, the device comprising: a. a clip portion having a body defining a stud engagement portion and a first engagement portion; b. a bracket portion having a body defining a second engagement portion complementary to the first engagement portion; c. a first resilient member at least a portion of which is located between the first and second engagement portions; and d. a second resilient member provided on at least a portion of the stud engagement portion.

2. A device in accordance with Claim 1, wherein the second engagement portion comprises a channel defined by the bracket portion body.

3. A device in accordance with Claim 2, wherein the first engagement portion is received within the channel of the bracket body.

4. A device in accordance with any preceding Claim, further comprising a retention member for retaining the first and second engagement portions in complementary inter-engagement with one another.

5. A device in accordance with Claim 3, wherein the retention member comprises one or more projections extending from the bracket portion body which abut against the resilient member located between the bracket portion and clip portion when the first and second engagement portions are engaged with one another.

6. A device in accordance with any preceding Claim, wherein the bracket portion is further provided with stud engagement means.

7. A device in accordance with any preceding Claim, wherein the clip portion further comprises A' channel engagement means.

8. A device in accordance with Claim 7, wherein the clip body further defines a channel, the walls of the channel defining the A' channel engagement means.

9. A device in accordance with Claim 8, wherein the walls of the clip body comprise opposing projections forming a spring clip arrangement for complementary inter-engagement with the A' channel.

10. A device in accordance with any preceding Claim, wherein the resilient member is composed at least in part of a foam material

11. A device in accordance with Claim 10, wherein the foam material is an closed cell foam material

12. A device in accordance with Claim 11, wherein the closed cell foam material has a density within the range 30 kg/rn3 to 110 kg/rn3.

13. A device in accordance with Claim 10, wherein the foam material is an open cell foam material.

14. A device in accordance with Claim 13, wherein the open cell foam material has a density within the range of 30 kg/rn3 to 200 kg/rn3.

15. A system for reducing acoustic coupling between two surfaces, the system comprising: a. a first substantially planar surface; b. a plurality of devices in accordance with any one of Claims 1 to 14, coupled to the first surface; c. a plurality of A' channels, each A' channel coupled to a device; and d. a second substantially planar surface coupled to the plurality of A' channels, such that the two surfaces are substantially parallel to one another.

16. A system in accordance with Claim 15, wherein the first surface comprises a wall.

17. A system in accordance with Claim 15, wherein the first surface comprises a stud frame coupled to a partition wall;

18. A system in accordance with Claim 15, wherein the first surface comprises a ceiling joist arrangement.

19. A method of production of an acoustically decoupled partition wall arrangement comprising the steps of: a. providing an upper rail and a second substantially parallel lower rail; b. providing a plurality of spatially separated substantially parallel vertical rails and coupling the substantially vertical rails to the upper and lower rails in an acoustically isolated manner; is c. providing a. plurality of devices in accordance with any one of Claims I to 14 and coupling the devices to two opposing surfaces of the substantially vertical rails such that the devices extend away from the vertical rails in a direction perpendicular to the elongate axis through the substantially vertical rails; d. providing a plurality of'A' channels and coupling each A' channel to a corresponding device such that each A' channel extends between the upper and lower rails; and e. providing two partition walls and coupling a partition wall to each of the opposing surfaces of the substantially vertical rails by means of the A' channels such that each partition wall is substantially parallel to the other with the rails, devices and A' channels located therebetween.

20. A device substantially as hereinbefore described and with reference to the accompanying drawings.

21. A system substantially as hereinbefore described and with reference to the accompanying drawings.

22. A method substantially as hereinbefore described and with reference to the accompanying drawings.