Field of the Invention

The present invention relates to an insert suitable for mounting in an element, e.g. a wall, a ceiling, etc.

Background of the Invention

A recessed light or downlight is a light fixture that is installed into an opening in a surface, normally a ceiling. The exposed face of the light fixture is normally substantially flush with the surface of the ceiling, with further associated housing and circuitry positioned in the plenum (e.g. the space or cavity above the ceiling and below the succeeding floor). It is known to provide the housing and circuitry as part of an insert that is inserted into the plenum through the surface opening. Furthermore, such inserts are often installed beneath a layer of suitable insulation material (e.g. fibre glass mats), which is also located in the plenum. Once such an insert is installed in the opening, the electrical fittings (normally in the form of a light bulb to provide the recessed lighting) can be mounted in the insert for operation.

Due to the normally restrictive space available for the mounting of such inserts, insert designs have been developed which provide for easier installation of the insert in a surface opening. In these cases, the insert comprises a housing for receiving an electrical fitting, and a power pack or electrical circuit element which is flexibly coupled to the housing. The electrical circuit element may comprise any junction box, switches, transformers, etc. which are necessary for the operation of a contained electrical fitting. This allows for the insert to be flexible in profile during a mounting operation, allowing for easier manipulation and adjustment during installation. An example of such an insert can be found in European Patent Application Pub. No. EP 2 157 370 A2. It is known to provide ventilation in an insert housing for the purposes of cooling a contained electrical fitting, thereby improving the performance and lifetime of the fitting itself. An example of such an insert can be seen in International Patent Application Pub. No. WO 2005/059435 Al . However, such a ventilation configuration requires additional framework about the ventilation device in order to provide space for airflow, resulting increased height of the device which provides a design of insert which increases the difficulty of installation in restrictive spaces. Furthermore, relatively complicated multi-stage mounting operations are required for the installation of inserts. In International Patent Application Pub. No. WO 2009/080046 Al, an insert having a two-part housing is disclosed, wherein the insert is installed in an opening in a surface by the manipulation of an inner and an outer mounting box, and coupling tabs which engage therebetween. Such an operation is relatively complicated, and requires considerable effort when operating in restricted space environments.

Object of the Invention

It is an object of the invention to provide an insert that combines easy insertion with improved lifetime and performance of the electrical fitting installed therein. There is also provided an improved system and method for the installation of an insert for an electrical fitting.

Summary of the Invention

Accordingly, there is provided an insert for an electrical fitting suitable for being placed in a construction element, the insert comprising:

an insert housing for receiving an electrical fitting in the interior of said insert housing;

an electrical circuit element flexibly coupled to an external surface of said in- sert housing, the electrical circuit element operable to power an electrical fitting received in the interior of the insert housing; and a ventilation means mounted adjacent said electrical circuit element, wherein said ventilation means is operable to cool the interior of said insert housing by generating an airflow about the interior of said insert housing. As the ventilation means acts to cool the interior of the insert housing, this improves the operational efficiency of the insert, and can help to prolong the lifetime of the insert and any associated fittings. As the ventilation means is mounted adjacent to the electrical circuit element, the ventilation device is also flexibly coupled to the insert housing, and accordingly may be adjusted relative to the housing when used in reduced space environments. Preferably, the electrical circuit element is hingedly coupled to the insert housing. By electrical circuit element, it will be understood that this may comprise any suitable housing and/or electrical circuitry required for the operation of an electrical fitting provided in the insert housing, e.g. one or more of the following: a power pack, a power supply, a junction box, a transformer, an electrical switch, remote control cir- cuitry, etc. Furthermore, it will be understood that such an insert may be used for installation in any suitable construction element, which may comprise a planar surface, e.g. a ceiling, a wall, a floor, a piece of furniture, etc. It will be understood that the ventilation means itself may be flexibly coupled to the insert housing via a separate coupling, and provided adjacent said electrical circuit element.

Preferably, said ventilation means is operable to cool said electrical circuit element by generating an airflow about a portion of said electrical circuit element.

The air which is used for cooling will exit the insert into the room below the insert and provide a contribution to the heating and circulation in the room air. Especially in the zone just below the ceiling circulation will be provided, which can otherwise be a problem.

As the ventilation means is coupled to the electrical circuit element, this means that ventilation action (i.e. cooling) will occur in the vicinity of the electrical circuit element, regardless of the flexible positioning of the electrical circuit element relative to the insert housing. When the light source mounted in the insert is a LED device it is important to maintain the temperature around the light source as low and stable as possible. This will improve the emitted light intensity and prolong the service life of the device. If there was provided no ventilation in the insert the temperature for a typical 10 W LED device would increase to 85-90 degrees C°. With ventilation however the temperature is around 65 - 70 degrees C°. Traditionally the cooling is carried out by means of cooling ribs - typically made of aluminium or ceramics. In addition to being passive heat-conductors, placed in a badly ventilated space (between for example the ceiling and the insulation) they require extra built in volume which often is not possible.

The problem is further increased when halogen light-sources are used. Already with 20 - 35 W the generated heat requires special installations in order to protect the surrounding environment from the generated heat. Usually this is solved by light and heat reflecting shields, but still the operational temperature is elevated and above the optimal operating temperature. Also in the transformer generates a substantial amount of heat. In the example with halogen light sources the interior temperature in the transformer increased to approx. 110 - 115°C. By mounting the ventilator immediate the transformer the air flow caused by the ventilator lowered the temperature in the transformer by approx. 30°C. Preferably, said ventilation means comprises a ventilation inlet and a ventilation outlet; wherein said ventilation inlet is arranged adjacent said electrical circuit element, and said ventilation outlet is provided at an internal surface of said insert housing.

The ventilation inlet is arranged to intake air from the region about the electrical circuit element, and the ventilation outlet is arranged to output air into the interior of the insert housing. The sucking in of air at the inlet creates an air flow about the electrical circuit element, resulting in a cooling action. As the air taken in by the ventilation means is then output into the interior of the housing, this has the effect of contributing to the cooling of any electrical fittings which may be installed within the insert. By this arrangement of the ventilation means, both the inward and outward flows of air act to cool the device, and thereby improve the operation of the insert and any contained electrical fittings. Preferably, said ventilation outlet is off-set from the centre of said insert housing.

As the outlet is off-centre, this allows for the creation of a cooling vortex of swirling air within the interior of the insert housing, which results in a more effective cooling action of any contained electrical fittings.

Preferably, said ventilation means is operable to reverse the direction of air flow of the ventilation system. Preferably, said insert housing comprises an open end and a closed end, wherein said ventilation outlet is provided proximate said closed end of said housing.

As the outlet is provided towards the closed end of the housing, the output air flows through the majority of the interior of the housing before exiting at the open end of the housing. This allows for a greater cooling action of an electrical fitting contained within the housing.

Preferably, said closed end is arranged to engage with an electrical fitting to be received in said insert, and wherein said closed end of the housing comprises a thermally conductive element.

The use of an element having a relatively high thermal conductivity allows for additional heat to be conducted away from an electrical fitting installed in the insert. This increased surface area of relatively high temperature material increases the efficiency of the cooling action of the ventilated air, as more surface area is available from which to conduct heat away.

Preferably, said element comprises a ceramic plate. It will be understood that any other suitable material having a relatively high thermal conductivity may be used.

Preferably, said insert housing comprises a substantially tubular housing, wherein said ventilation outlet is provided adjacent a side wall of said substantially tubular housing. Preferably, said ventilation outlet is arranged such that the face of the outlet opening is substantially orthogonal to the internal surface of the adjacent side wall.

As the open face of the outlet is substantially orthogonal to the side wall adjacent to the outlet, this means that the airflow is introduced into the interior of the housing along the internal side wall surface. In the case of a substantially cylindrical housing, this can result in a swirling vortex effect of airflow within the housing, which can increases the air flow rate within the housing. Accordingly, the cooling action of the ventilated air can be increased.

Preferably, said ventilation outlet is arranged such that the face of the outlet opening is substantially orthogonal to the open end of the housing.

As the outlet is substantially orthogonal to the open face of the housing, this means that the airflow is not immediately directed straight out of the housing through the open end. Rather, the airflow can be directed towards the interior of the housing, where any electrical fittings are housed, thereby cooling the fittings.

Preferably, said ventilation means comprises a flexible conduit connecting said ventila- tion inlet to said ventilation outlet.

As the electrical circuit element is flexibly coupled to the insert housing, a flexible fluid connection is provided between the inlet and the outlet of the ventilation system to ensure that the fluid connection between the two is not broken during movement of the powelectrical circuit element relative to the housing.

Preferably, said ventilation means comprises a fan.

Preferably, said fan is provided at the ventilation inlet.

Preferably, said ventilation inlet is mounted adjacent said electrical circuit element. Preferably, at least one support flange is provided at a distal end of said electrical circuit element, wherein said at least one support flange projects from the same side of said electrical circuit element as said ventilation inlet. The support flange can normally be used to support the distal end of the electrical circuit element on a surface adjacent the insert housing. In this case, the at least one support flange may act as a buffer, or a shield, for the ventilation inlet. As the normal use of such an insert for an electrical fitting the insert will be encased in insulation material, therefore the support flange may act to preserve the airway into the ventilation inlet. Furthermore, the support flange acts to preserve the air flow about the electrical circuit element. It will be understood that said ventilation inlet and/or said support flange may be arranged in any suitable configuration, for example mounted directly to said electrical circuit element, mounted to a housing of said electrical circuit element, mounted to a support bracket to which said electrical circuit element is provided on, etc. The sup- port flange may be selected to be a suitable length to preserve the air flow for the ventilation inlet and/or about the electrical circuit element.

Preferably, said insert comprises a temperature sensing element wherein said ventilation means is actuated at a particular temperature level detected by said temperature sensing element.

Preferably, said electrical circuit element is pivotably connected to said insert housing. Preferably, said connection is a hinged connection. Preferably, said flexible connection comprises at least two pivot points.

In a further embodiment of the insert a one way valve is arranged between the ventilation inlet and ventilation outlet, where said one way valve only allows airflow into the insert. According to the modern building codes, buildings have to be airtight to a cer- tain degree. These is generally tested by increasing the interior air pressure and monitor the decrease in pressure over time, as an indication of the buildings' air-tightness. It is therefore important in areas where this requirement is in force, as it is in Denmark, that an air leak is not provided through the insert, by means of the ventilation means. The one-way valve is therefore mounted in the air channel between the ventilation means and the interior of the insert. In preferred embodiments the valve is integrated in the ventilator, or the inlet construction in the insert wall. An additional advantage by mounting the ventilation means free from the inserts housing is that the noise generated by the ventilator is not directly transmitted to the connecting room, but will be dampened. The dampening effect is further enhanced by the insulating material. In another aspect, there is provided a mounting collar for an insert for an electrical fitting, the mounting collar adapted to mount the insert in an aperture in a ceiling, the mounting collar comprising:

a circular collar body adapted to couple with a housing of an insert for an electrical fitting; and

a displacement means arranged to deform said circular collar body against the walls of an aperture to secure said mounting collar in said aperture.

It will be understood that the mounting collar may be adapted for use with any suitable insert for an electrical fitting.

Preferably, said mounting collar comprises a single split collar body having a split channel, and wherein said displacement means comprises a wedge member provided at said split channel. A single split collar can be thought of as a circular collar formed from a single planar member of material bent into a circular shape, the opposed ends of the planar member meeting at the "split" point of the collar, forming a channel between the opposed ends.

Preferably, the mounting collar comprises an actuation member coupled to said wedge member, said actuation member operable to advance said wedge member within said split channel to expand said the diameter of said collar body. As the wedge member is advanced in the channel, the wedge member acts against the opposed ends of the planar material forming the collar body, forcing the ends apart. As the ends are forced apart, the diameter of the circle formed by the collar body is increased, which allows the mounting collar to act against the walls of the aperture, se- curing the collar in position within the aperture.

Preferably, said wedge member is provided within a chamber formed at said split channel. As the wedge member is provided within a chamber formed at the split channel, accordingly the wedge member is secured within the collar body, and is unlikely to become dislodged or lost.

Preferably, said wedge member comprises a through-going threaded bore defined therein, and wherein said actuation member comprises a threaded bolt coupled to said collar body and extending through said threaded bore.

The use of a threaded bore and bolt system provides an actuation system which is easily constructed and reliable.

Preferably, the collar body comprises an internal collar wall and an external collar wall, and wherein the mounting collar comprises at least one engagement member provided on the surface of the external collar wall. The use of engagement members on the exterior of the collar allows for the collar to couple with the walls of an aperture into which it is desired to mount an electrical fitting insert.

Preferably, said at least one engagement member is substantially tapered.

Preferably, said at least one engagement member is pointed. The at least one engagement member may be for example a spike, a point, a pin. Alternatively, the external surface of the mounting collar body may be barbed. Preferably, at least one coupling channel is provided on an internal collar wall of the circular collar body, the at least one coupling channel arranged to receive an engagement member provided on the housing of an insert for an electrical fitting to couple said mounting collar to said insert.

The coupling channel engages with a projection provided on the exterior of the insert, to couple the mounting collar to the insert. Preferably, at least a portion of said at least one coupling channel is substantially helical.

The use of an at least partially helical channel allows for a secure coupling to be made, as the insert is less likely to become dislodged from the mounting collar, as a helical (or twisting) coupling action is required to install the insert in the collar.

There is further provided a method for installing an insert for an electrical fitting in a planar surface, the method comprising the steps of:

providing an aperture in a planar surface;

inserting a mounting collar in said aperture;

actuating said mounting collar to expand the mounting collar against the walls of said aperture to secure said mounting collar in place in said aperture;

positioning an insert for an electrical fitting in said aperture, wherein said insert is substantially passed through said mounting collar; and

coupling said insert to said mounting collar to secure said insert in said aperture.

The use of the mounting collar in the installation operation allows for relatively easier installation. Description of the Invention

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of an insert for an electrical fittings according to the invention;

Fig. 2 is a side plan view of the insert of Fig. 1;

Fig. 3 is a front plan view of the insert of Fig. 1;

Fig. 4 is a top plan view of the insert of Fig. 1;

Fig. 5 is a cross-sectional close-up view of the upper end of the interior of the insert housing of the insert of Fig. 1;

Fig. 6 is a perspective view of a mounting collar according to another aspect of the invention;

Fig. 7 is a cross-sectional close-up view of a portion of the collar of Fig. 6; and Fig. 8 is a perspective view of a displacement means used with the collar of Fig. 6.

With reference to Figs. 1-4, an insert for an electrical fitting is indicated generally at 10. The insert 10 comprises an insert housing portion 12 and a electrical circuit element portion 14. The insert housing 12 comprises a substantially tubular container having an open end 16 and a closed end 18, side walls 20 extending therebetween.

The electrical circuit element 14 comprises an elongate housing 14a which is hingedly coupled to the insert housing 12. The electrical circuit element 14 is mounted on a first support bracket 22 having a first free distal end 22a and a second hinged end 22b. The hinged end 22b of said first support bracket 22 is connected via first hinge 24 to a first end 26a of an L-shaped second support bracket 26, said second support bracket 26 connected to the closed end 18 of said insert housing 12 via second hinge 28.

By electrical circuit element 14, 14a, it will be understood that this may comprise any suitable housing and/or electrical circuitry required for the operation of an electrical fitting provided in the insert housing 12, e.g. one or more of the following: a power pack, a power supply, a junction box, a transformer, an electrical switch, remote control circuitry, etc. Furthermore, it will be understood that the electrical circuit element 14,14a may be coupled to the insert housing 12 in any suitable manner to allow the electrical circuit element 14,14a to be adjusted relative to the insert housing 12, e.g. flexible plastic coupling, any suitable pivot, pitch, or swivel joint, etc. It will also be understood that the electrical circuit element 14 may be flexibly coupled to any portion of the insert housing 12, i.e. not just to the closed end 18 of the housing 12.

Electrical connection means in the form of wires 30 extend from the electrical circuit element 14 through a first aperture 32 provided in the second support bracket 26 and through a second aperture 34 provided in the insert housing 12, to the electrical con- nection apparatus (indicated at 36, Fig. 5) provided within the insert housing 12. The electrical connection apparatus 36 can be coupled with an electrical fitting (not shown) to be installed in the insert 10 to provide power to the fitting from the electrical circuit element 14. The double hinging of the electrical circuit element 14 to the insert housing 12 provides two degrees of freedom for manipulation of the electrical circuit element 14 relative to the insert housing 12, e.g. during installation of the insert 10 in a plenum.

A ventilating device in the form of a fan 38 is mounted on the first support bracket 22 on the underside of the electrical circuit element 14. A fan grill 40 is provided over an inlet of the fan 38. The fan 38 is coupled to a first end of a flexible tube 42, the second end of which is coupled to a ventilation outlet (44, Fig. 5) provided on the interior of the insert housing 12. The fan 38 is operable to draw in air from the region about the electrical circuit element 14, and to drive the collected air through the tube 42 to the outlet 44. As the fan 38 creates an air flow around the electrical circuit element 14, the electrical circuit element 14 and any contained components will be cooled, which can result in improved operation of the electrical circuit element 14 and components, and may lead to in- creased operational lifetime of the device. Any suitable fan or ventilator device may be used. Preferably, said ventilator device has the approximate dimensions of 18mm x 18mm. Preferably, the device has an average flow rate of between 1 ltr/min to 50 ltrs/min. A pair of support flanges 46 are provided at the distal end 22a of the first support bracket 22, projecting beneath the electrical circuit element 14. Said support flanges 46 can be used to support the electrical circuit element 14 on a surface in the plenum, and can also be used to ensure that sufficient space is maintained about the fan 38 to allow for a suitable airflow to be created going into the fan 38, and also to prevent blockages of said fan 38. As the fan 38 and the support flanges 46 are provided at the same side of the electrical circuit element 14, the fan is naturally shielded by the support flanges 46, and foreign material, e.g. insulation material, can be prevented from interfering with the operation of the fan 38.

It will be understood that different configurations or profiles of support flanges 46 may be used to shield the input to the fan 38. With reference to Fig. 5, the ventilation outlet 44 is provided adjacent the internal surface of the support wall 20 of the insert housing 12, towards the closed end 18 of the housing 12. The outlet 44 is arranged so that the open face of the outlet 44 is substantially orthogonal to the interior surface of the side wall 20 which is immediately adjacent the opening of the outlet 44. Furthermore, the outlet 44 is arranged so that the opening of the outlet does not directly face towards the open end 16 of the insert housing 12 - in Fig. 5, the plane of the open face of the outlet 44 is substantially orthogonal to the plane of the open end 16 of the housing 12.

Due to the arrangement of the outlet 44, air flowing from the fan 38 through the tube 42 exits the outlet 44 and abuts the internal surface of the side wall 20 of the housing 12. The air flow continues to follow the profile of the side wall 20 as indicated by the direction of arrow A, which results in a swirling vortex of air flow within the insert housing 12. Such a rapidly swirling air flow will act to cool any electrical fittings contained within the housing 12, thereby improving their performance and operational life- time. As the air flow is heated, the continual flow of new air into the interior of the housing 12 via outlet 44 forces the heated air out of the housing 12 through the open end 16, wherein the air heated by the electrical fittings may be used to disperse said heat to the room below the insert. Furthermore, a portion of the closed end 18 of the insert housing 12 may be formed from a material having a relatively high thermal conductivity, e.g. a ceramic plate. The use of such a material will help to conduct some heat away from the contained electri- cal fitting, thereby providing a greater surface area over which the introduced air flow can come into contact with. This increase area can increase the rate of conduction of heat away from the insert 10 and the contained fitting, improving the cooling action of the insert 10. Through this configuration of insert 10, it has been found that the operating temperature of a standard LED downlight light bulb can be reduced from a normal operating temperature of approximately 80° - 100° (without cooling), to approximately 55° (when ventilation and cooling system is operating). Such a reduction in temperature results in improved operation of the device and increased device lifetime.

It will be understood that any suitable arrangement of the outlet 44 may be used to produce an air flow within the insert housing 12, such that any electrical components contained within the housing 12 are cooled by said airflow. In the embodiment of the insert 10 shown in the figures, the insert housing 12 is formed from an assembly of a substantially cylindrical open-ended tube and an end cap, with the ventilation outlet 44 provided on said end cap. In this case, the entire end cap may be formed from said thermally conductive material. However, it will be understood that any suitable construction of insert housing 12 may be used, for example the housing may be formed from a single moulded member. Furthermore, said ventilation outlet 44 may be provided at any position on the interior of the insert housing 12.

The insert 10 may further be provided with a mechanism to reverse the air flow direction of the device, e.g. so that fan 38 is operable to draw air into the flexible tube 42 through the outlet 44 and output it through grill 40.

The insert 10 may further comprise a thermal switching element (not shown), said thermal switching element operable to activate the ventilation system (e.g. fan 38) of the insert when a particular temperature is detected. Said thermal switching element may also be operable to deactivate the ventilation system at a particular temperature. Such operation of the device may allow for more efficient power consumption, as the ventilation system is only actuated when needed. Such a thermal switching element may comprise any suitable temperature sensing device, e.g. a thermostat, a bi-metallic element, a capacitative temperature sensor, etc.

Turning to Figs. 6-8, a mounting collar for an insert for an electrical fitting is indicated generally at 50. The mounting collar 50 comprises a single-split circular collar body 52, having first and second collar ends 52a, 52b which abut at the split channel 54 of the collar body 52.

With reference to the cross-sectional view shown in Fig. 7, the split channel 54 is shaped to form a chamber 56 between said first and second collar ends 52a,52b. A di- agonal bearing surface 58 is provided at the first collar end 52a side of the chamber 56, such that an upper end 56a of said chamber 56 is wider relative to a lower end 56b of said chamber 56. Upper and lower lug members 60a,60b project from the second collar end 52b at respective upper and lower ends 56a,56b of the chamber 56, said lug members 60a,60b having respective apertures defined thereon.

With additional reference to Fig. 8, the chamber 56 is dimensioned to receive a wedge member 62, comprising a tapered body having a wedge bearing surface 64. The wedge member 62 further comprises a through-going threaded bore (not shown) defined therein, said bore extending from a relatively wide end 62a of said wedge member 62 to a relatively narrow end 62b of said wedge member 62

A threaded bolt 66 extends through said threaded bore of said wedge member 62, from a head end 66a of said bolt 66 proximate said narrow end 62b of said wedge member 62 to a free end 66b proximate said wide end 62a of said wedge member 62. As the bolt 66 and the through going bore of the wedge member 62 are threaded, the wedge member 62 can be advanced along the length of the bolt 66 through appropriate twisting of the bolt head 66a. A pair of nuts 68 are provided at said free end 66b of said bolt 66, to retain said wedge member 62 on said bolt 66. (Note the drawing of bolt 66 is shown without threads in Fig. 8 for clarity reasons.)

In use, wedge member 62 is provided in the chamber 56 of the mounting collar 50, the wide end 62a of the wedge member 62 adjacent the upper end 56a of the chamber 56. The free end 66b of bolt 66 is inserted through lower lug 60b, through the bore in the wedge member 62 and through the upper lug 60a. Nuts 68 are then applied to the free end 66b of the bolt 66 to prevent the bolt 66 from becoming dislodged from the collar 50.

It is possible to increase the diameter of the collar body 52 by actuating the bolt head 66a, thereby moving the wedge member 62 along the body of the bolt 66 so that the wedge bearing surface 64 acts upon the diagonal bearing surface 58 of the first collar end 52a of the collar body 52. As the wedge member 62 is advanced, the first collar end 52a is forced away from the second collar end 52b due to the bearing action of the wedge member 62 on the diagonal bearing surface 58.

Returning to Fig. 6, a series of protrusions 70 are provided on the external surface of the collar body 52. In Fig. 6, the protrusions 70 are illustrated as pointed stud mera- bers, but it will be understood that any suitable protrusion profiles may be used, for example a spike, a point, a pin. Alternatively, at least a portion of the total external surface of the mounting collar body 52 may be barbed. The protrusions 70 act to dig into a surface of an aperture into which the mounting collar 50 is to be installed, the protrusions 70 being forced into said aperture surface through continued widening of the diameter of the collar body 52 using the wedge member 62.

At least one coupling channel 72 is defined on the internal surface of the collar body 52, the coupling channel 72 dimensioned to receive an engagement member (not shown) provided on the external surface of the side walls 20 of an insert housing 12. The engagement member may comprise any suitable projection or coupling element capable of coupling the mounting collar 50 to an insert housing 12. The coupling channel 72 shown in Fig. 6 is substantially helical, as it twists about a portion of the internal surface of the collar body 52. Accordingly, an insert housing 12 may be coupled and secured to the collar 50 through insertion of an appropriate engagement member into said channel 72 and appropriate twisting of said housing 12 relative to said collar body 52 to force the engagement member to the end of the coupling channel 72.

It will be understood that any suitable configuration of coupling channel 72 may be used that is suitable to couple the mounting collar 50 to the insert housing 12. Fur- thermore, additional locking mechanisms may be employed in order to secure the mounting collar 50 to an insert housing 12, e.g. a latch, bolting, a snap-fit coupling, etc.

It will be understood that the mounting collar 50 of Figs. 6-8 may be used with any suitable insert for an electrical fitting, and is not limited to the insert embodiment illustrated in Figs. 1-5.

When installing said mounting collar 50, initially a generally circular aperture is formed in a surface, usually a ceiling. This can be accomplished using any suitable cutting means. The mounting collar 50 is then positioned within said aperture, said mounting collar 50 being initially configured in its smallest diameter state, i.e. the wedge member 62 is provided abutting the wide upper end 56a of the chamber 56, and does not bear against the diagonal bearing surface 58. The bolt head 66a of the bolt 66 may then be actuated, so that the wedge member 62 is advanced to bear against the diagonal bearing surface 58 of the first collar end 52a. This forces the collar body 52 to expand in diameter, the external surface of the collar body 52 acting against the walls of the aperture, and the collar projections 70 digging in to the aperture walls, securing the mounting collar 50 in position in the aperture.

Once the mounting collar 50 is secured, the insert 10 may be installed in the aperture. This may involve initially connecting the electrical circuit element 14 to an electrical connection present in the plenum or cavity through the aperture, and accordingly through the interior of the mounting collar body 52. Once such connection is established, the insert 10 comprising the electrical circuit element 14 and the insert housing 12 may be inserted into the plenum though the mounting collar 50. The flexible coupling of the electrical circuit element 14 to the insert housing 12 allows for increased adaptability and flexibility of such an operation, as the electrical circuit element 14 may be manoeuvred relative to the insert housing 12.

Once the insert housing 12 is moved into position, the housing 12 is coupled to the mounting collar 50 by inserting the engaging member present on the external surface of the side walls 20 of the housing 12 into the coupling channel 72 present on the internal surface of the collar body 52. The housing 12 may then be secured in position to the mounting collar 50 by performing a locking operation suitable to the engagement system used. (In the embodiment shown in Fig. 6, this is accomplished by twisting the housing 12 to lock into the helical coupling channel 72 of the collar body 52.)

Once the insert 10 is secured in position, an appropriate electrical fitting can then be installed into the insert 10 for normal operation.

The invention is not limited to the embodiments described herein, and may be modified or adapted without departing from the scope of the present invention.