AU715099B2

AU715099B2 - Mounting device

Info

Publication number: AU715099B2
Application number: AU52079/98A
Authority: AU
Inventors: Noel S D Wood
Original assignee: HPM Industries Pty Ltd
Current assignee: HPM Industries Pty Ltd
Priority date: 1993-11-12
Filing date: 1998-01-15
Publication date: 2000-01-13
Anticipated expiration: 2014-09-30
Also published as: AU5207998A

Description

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AUSTRALIA

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a a a Invention Title: MOUNTING DEVICE The following statement is a full description of this invention, including the best method of performing it known to us: GH REF: P04210-WH:RW/LN 2 This invention relates to a mounting device which is intended to be secured to a wall cladding and to extend into a cavity behind the wall cladding. The mounting device has been developed as one which is intended to receive an electrical fitting such as an electrical switch, a power outlet, an antenna socket, a telephone connector or a computer network outlet. However, it will be understood that the mounting device may have other diverse applications.

The mounting device may be formed as a casing and be used as a wall box for the purpose of minimising the risk of fire passage between rooms sharing a common wall. The invention is hereinafter described in the context of a wall box which is suitable for this purpose. However, it will be 15 understood that the invention does have broader application.

.Electrical fittings such as light switches and switched power outlets are normally mounted to wall claddings by way of mounting brackets or wall boxes. The brackets or wall boxes themselves are normally secured to wall studs behind the claddings and, in the case of hotels and other public 0*000* S• buildings, restrictions normally are imposed on the positioning and mounting of the electrical fittings in order to minimise the risk of flame movement between adjacent rooms following damage being done to an electrical fitting in one of the rooms. For example, it is a normal requirement that electrical fittings in adjacent rooms be displaced laterally relative to one another but, whilst this may minimise the risk of fire transfer between rooms, it does create wiring difficulties, particularly if wall studs impede wiring between the fittings.

The present invention provides a mounting device which may be mounted directly to a wall cladding (ie, independently of a wall stud or other structural element) and which is constructed as a wall box which may be used to minimise the risk of fire transmission. The invention may 04210wh/15.01.98 3 also be adapted to minimise the transmission of acoustic energy through a wall to which the wall box is mounted.

The invention may be defined broadly as providing a mounting device in the form of a wall box that comprises a support member which is arranged to be projected into an aperture within a wall cladding to which the mounting device is to be secured, a heat activatable intumescent material located within the support member for the purpose of protecting against flame propagation, lateral projections provided on the support member and arranged to limit the extent of projection of the mounting device into the aperture, and two oppositely disposed fixing elements mounted within the support member and arranged to be projected outwardly in mutually opposite directions from within the support member. Each fixing element has a tongue which is arranged and disposed either to locate immediately behind or to project into the cladding element when the fixing elements are projected outwardly from within the support member. Also, the fixing members are provided with holes that are arranged to receive screws that are employed in use to secure the fixing elements in fixed positions when they have been projected outwardly to predetermined extent.

The tongues of the fixing elements function to secure S 25 the mounting device to the cladding, either by penetrating the cladding itself and acting as anchors or by locating behind the cladding and co-operating with the lateral :projections of the support member to sandwich and clamp the cladding at regions around the aperture. The mounting 30 device may be provided in a form in which the tongues actually penetrate the cladding when the device is to be used in conjunction with a cladding which is formed from a soft material such as exists in a plasterboard cladding.

The mounting device may be constructed in a form in which the tongues of the fixing elements locate immediately A41 behind the cladding when the cladding itself is formed from 04210wh/12.11.99 a harder material, such as may not conveniently be penetrated by the tongues of fixing elements.

The screws that are used to secure the fixing elements may be one and the same as the screws that are used to mount an electrical fitting to the mounting device and, thus, the screws need not form a part of the mounting device as such.

The support member itself may be formed with a base and three or four surrounding sides; that is, as an open wall box with the fixing elements mounted to opposite sides of the box structure. In such case, the sides of the structure to which the fixing elements are mounted will each have a slot through which the tongue of the associated fixing element is projected to enter the cladding or to locate behind the cladding as the case may be.

The invention will be more fully understood from the following description of a preferred embodiment of a wall mounting box which includes the inventive features. The description is provided with reference to the accompanying drawings in which: Figure 1 shows a perspective view of the wall box in finally assembled condition; Figure 2 shows a plan view of the wall box as seen in the direction of arrow 2 in Figure 1 in the course of mounting the r wall box to a wall; 25 Figure 3 shows a front elevation view of the wall box as seen in the direction of arrow 3 shown in Figure 1; Figure 4 shows a plan view of the wall box which is similar to that shown in Figure 2, but with the wall box finally mounted to the wall and carrying an electrical fitting; 9999 30 Figure 5 shows an end elevation view of the wall box as .o seen in the direction of section plane 5-5 shown in Figure 4; Figure 6 shows an exploded perspective view of one end of the wall box as seen in the direction of arrow 6 shown in Figure 1; and 04210wh/12.11.99 5 Figure 7 shows a view similar to that which is shown in Figure 4 but which illustrates a second (alternative) embodiment of the invention.

As illustrated, the wall mounting box comprises a pressed and folded sheet metal support member 10 having a rear wall or base portion 11 and three sides walls 12, 13 and 14. In a further embodiment of the invention (not shown), a fourth side wall may be added so that the walls enclose all but the front opening of the wall box.

The wall box is arranged to be projected into a generally rectangular aperture 15 (Figures 2 and 4) within a wall cladding 16, such as a plasterboard or similar type of cladding. Triangular-shaped lateral projections 17 are formed as extensions of the side walls 12 and 14 and are 15 provided to limit the maximum extent to which the wall box .may be projected into the aperture Two similar pressed metal fixing elements 18 and 19 "(referred to herein as pivot elements) are pivotably mounted the side walls 12 and 14 and serve as fixing elements or, in the case of the Figure 7 embodiment, clamping elements S•for the wall box. One of the pivot elements 19 is shown in detail in Figure 6 of the drawings and it comprises a generally U-shaped element having two substantially parallel limbs 20 and 21 which are joined by a bridging piece 22.

Notches 23 are provided in the limb 20 and a stepped recess 24 is provided in each of the walls 12 and 14 of the wall box to receive the limb 20 of the respective pivot elements 18 and 19. The recess 24 is shaped to retain the notched limb 20 and, at the same time, to permit pivotal movement of the complete pivot element.

The second limb 21 of each of the pivot elements 18 and 19 is longer than the first limb 20 and is formed with serrations 25. The limb 21 also projects through a stepped recess 26 in each of the side walls 12 and 13 of the wall box, and the limb 21 is formed with notches 27 which are 04210wh/15.01.98 6 positioned to co-operate with the stepped recess 26 in each of the side walls 12 and 14.

A cut-out 28 is provided in the bridging portion 22 of each of the pivot elements 18 and 19 and a tapped hole 29 is located in the limb 21.

When securing the wall box to the wall cladding 16, the wall box is first projected through the aperture 15 as shown in Figure 2. Thereafter, a screw driver blade or other similar implement is inserted through the cut-out 28 and is employed to pivot (ie, lever) each of the pivot elements 18 and 19 from the position shown in Figure 2 to that which is *shown in Figure 4. That is, the serrated limb 21 of each pivot element is moved through its stepped recess and is forced into the adjacent edge of the cladding 16. The limb coo• 15 21 penetrates into the cladding and serves to anchor the wall box in position.

The two limbs 20 and 21 are initially forced in a '.*direction toward one another against the inherent resiliency of the material from which the pivot elements are made, but when the limb 21 has been moved into its recess to a sufficient extent, the notches 27 in the limb 21 align with shoulders 31 in the stepped recess 26. At that point, the limbs tend to move apart slightly and the pivot elements are prevented from retracting backwardly into the wall box. The same thing happens in relation to the limb 20 of each pivot element, in that the notches 23 engage with shoulders 32 in the stepped recess 24.

After locating the wall box within the cladding aperture 15, a gasket 33 of acoustically absorbent material as positioned around the open front of the wall box and an electrical fitting mounting plate 34 is secured to the wall box by mounting screws 35. The screws 35 are directed through the mounting plate 34 and into the tapped holes in both of the pivot elements 18 and 19. The screws 35 serve the dual purpose of holding the mounting plate 34 in 04210wh/15.01.98 7 position and of locking the pivot elements in the fixed position indicated in Figure 4.

Electrical wiring connections 36 (Figure 5) are made to the electrical fitting (whatever it may be) at the back of the mounting plate 34 before the mounting plate is positioned and secured to the wall box.

A pad 37 of heat activated intumescent material is glued to the rear wall 11 of the wall box, as shown in Figures 4 and 5, and functions to seal the wall box against flame propagation in the event of a fire condition. That is, should heat exist at such a level as to melt the mounting plate and create a flame path through the wall box, the pad of intumescent material 37 will expand to fill a major portion at least of the wall box, close the opening 15 through which the wiring 36 extends and thereby seal the .wall box against the passage of flames.

In an alternative arrangement of the invention, as *[.shown in Figure 7 of the drawings, modified fixing elements 38 are shaped and dimensioned such that their forward limbs locate not within the edge of the cladding but behind the cladding 16. The screws 35 in this case are used to draw the limbs 39 of the pivot elements toward the mounting plate 34 at the same time as the mounting plates are being secured to the wall box. Thus, the wall cladding is effectively clamped between the mounting plate and the limbs 39 of the fixing elements and, so, the assembly of the wall box and mounting plate is secured in position.

04210wh/15.01.98

Claims

1. A mounting device in the form of a wall box that comprises a support member which is arranged to be projected into an aperture within a wall cladding to which the mounting device is to be secured, a heat activatable intumescent material located within the support member for the purpose of protecting against flame propagation, lateral projections provided on the support member and arranged to limit the extent of projection of the mounting device into the aperture, two oppositely disposed fixing elements mounted within the support member and arranged to be projected outwardly in mutually opposite directions from within the support member, each fixing element having a tongue which is arranged and disposed either to locate immediately behind or to project into the cladding element when the fixing elements are projected outwardly from within the support member, and the fixing members being provided with holes that are arranged to receive screws S 20 that are employed in use to secure the fixing elements in fixed positions when they have been projected outwardly to Sa predetermined extent.

2. The mounting device as claimed in claim 1 wherein the screws are employed also to secure to the support 25 member a fitting which is intended to be carried by the mounting device.

3. The mounting device as claimed in claim 1 or claim 2 wherein the support member is formed as an open box-like structure which is arranged to carry an electrical 30 fitting, the box-like structure having a base and side wall portions, and the fixing elements being mounted to opposite said side wall portions of the structure.

4. The mounting device as claimed in claim 3 wherein each side wall portion of the box-like structure is formed with a slot through which the tongue of an associated one R of the fixing elements projects. 04210wh/12.11.99 A mounting device as claimed in claim 3 or claim 4 wherein the fixing elements are pivotably mounted to the support member.

6. The mounting device as claimed in claim 5 wherein each fixing element is formed as a substantially U-shaped element having first and second limbs, wherein the tongue of each fixing element is constituted by a second of the limbs of the U-shaped element, and wherein each side wall portion of the box-like structure is formed with two slots through which the first and second limbs of the associated fixing element extend.

7. The mounting device as claimed in claim 6 wherein the second limb of each fixing element is longer than the first limb of the fixing element.

8. The mounting device as claimed in claim 6 or claim 7 wherein the slots through which the first limbs of the fixing elements extend are in the form of stepped recesses having shoulders, and wherein the first limb of each fixing element is formed with notches that are arranged to engage with the shoulders in the stepped recesses of the associated slots in a manner such that the first limb is held captive within the slot whilst being pivotable with respect to the side wall portion containing :the slot. 25 9. The mounting device as claimed in any one of claims 6, 7 or 8 wherein the slots through which the second limbs of the fixing elements extend are in the form of stepped-recesses having shoulders, and wherein the second a. limb of each fixing element is formed with notches that are arranged to engage with the shoulders in the associated stepped recesses, such that the extent of projection of the second limb through the associated slot is limited and retraction of the second limb from its outward pivotal position is prevented when the slots and shoulders engage.

10. The mounting device as claimed in claim 9 wherein the first and second limbs of each fixing element when. 04210wh/12.11.99 located within the respective slots in each side wall of the box-like structure are resiliently biased in a direction away from one another, whereby interengagement will occur between the notches in the second limbs and the shoulders within the associated recesses when the fixing elements have been pivoted outwardly and the second limbs project beyond the side walls of the box-like structure to a predetermined extent.

11. The mounting device as claimed in any one of claims 3 to 10 wherein a pad of the heat actuatable intumescent material is located within the box-like structure, the material being arranged to expand and fill at least a major portion of the box-like structure in the event of the mounting device being exposed to a predetermined temperature level.

12. A mounting device substantially as shown in the accompanying drawings and substantially as hereinbefore described with reference thereto. DATED this 12 th day of November 1999 H.P.M. INDUSTRIES PTY LTD By their Patent Attorneys GRIFFITH HACK 9* 9* 9 9 9 9 999 9o9.9 04210wh/12.11.99