AU2018208278B2

AU2018208278B2 - Improvements in Insulated Metal Doors

Info

Publication number: AU2018208278B2
Application number: AU2018208278A
Authority: AU
Inventors: Simon Marcus Parkes; Steven Geoffrey Parkes; Peter Bertaud Ramsden
Original assignee: Parkwood Products Ltd
Current assignee: Parkwood Products Ltd
Priority date: 2017-07-28
Filing date: 2018-07-23
Publication date: 2020-01-16
Anticipated expiration: 2038-07-23
Also published as: AU2018208278A1

Abstract

Abstract The invention relates to a door, with outer panels of metal sheets, that includes an insulating layer between them, to minimise or prevent unwanted ingress or loss of heat. The components of the door are specifically configured to be resilient, and / or are resiliently connected to one another. This means that expansion or contraction of a given component of the door (especially the outer panels) is substantially confined to that component. The other components of the door, for example the insulating layer, remain substantially stationary and unstressed. The door may therefore be less prone to temperature-related damage or failure. James & Wells ref: 307464AU / 47 100 12 116 18102 106 110

Description

IMPROVEMENTS IN INSULATED METAL DOORS

STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the provisional specification filed in relation to New Zealand Patent

Application No. 734143, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to insulated metal doors. The invention has particular application to aluminium doors, such as for installation in entranceways to buildings. However, the invention may also have ready application to doors formed from other metals or installed in other parts of buildings.

.0 BACKGROUND ART

Aluminium doors are known in the art and are often preferred for construction of buildings by virtue of their sleek and elegant appearance, relatively minimal weight, ease of manufacture and for other functional and aesthetic advantages.

Aluminium doors may commonly be formed as a shell of two parallel aluminium sheets. These may be connected to one or more sheets of a different material forming the internal structure of the door. For instance, a sheet of plywood may be sandwiched between and connected to the aluminium sheets.

The connection between the sheets of plywood and aluminium is typically rigid, such as provided by an industrial-strength adhesive applied continuously or intermittently to the surfaces of the plywood 20 and metal sheets that contact each other. This means that the sheets are not free to move with respect to each other.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

The door may typically also comprise additional components such as caps connected to the edges and / or corners of the sheets. Ancillary components, such as hinges, handles and / or locks, may be attached directly or indirectly to the sheet(s) by common techniques such as welding, adhesive, screws or other fastening means.

Aluminium is a thermally conductive material and as such, an uninsulated aluminium door may lead to unwanted ingress or egress (as the case may be) of heat into or out of a building. This may undermine the efficacy of central heating in winter, or of air conditioning in summer.

To help mitigate this problem, some aluminium doors may include an insulating layer formed from a material of relatively low thermal conductivity. This may be provided by a sheet(s) of polystyrene or .0 polyurethane foam rigidly connected to the interior structure of the door, such as using industrialstrength adhesive.

The rigid connections between the aluminium sheets and other structural sheets of the door (such as the plywood sheet and / or polystyrene sheet) as well as other components of the door may commonly lead to functional problems and damage to, or even failure of, the door.

.5 Aluminium has a relatively high thermal coefficient of expansion; that is to say, it tends to expand and contract by a significant amount in response to changes in temperature, meaning the length and / or width of the aluminium sheets may change by a relatively significant amount.

The other structural sheets forming the door tend to have a different thermal coefficient of expansion. For example, the plywood sheet may expand or contract by significantly less (potentially 20 up to ten times less) than the aluminium sheet, and the polystyrene sheet may expand or contract by significantly more (such as up to three times more) than the aluminium sheet.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

The relative expansion of the sheets by differing amounts may often result in damage or failure of the overall door structure. This may be exacerbated by the fact that the adhesive connecting the sheets of the door may tend to soften and weaken as temperature increases.

A particularly common problem is the aluminium sheets bowing or warping as they expand, 5 overcoming the adhesive bond and forming a bubble protruding away from the plywood sheet to accommodate their expansion relative to the plywood sheet.

Where a polystyrene insulating sheet is used, this may rupture or otherwise fail as it attempts to expand away from the aluminium sheet.

The caps at the edges and / or corners of the door may also be damaged by the stresses generated .0 as a result of the unequal expansion of the panels; as may other components of the door. Ancillary components, such as handles, hinges or locks, may be displaced out of alignment and thus not be able to function properly. This may prevent the door from closing and / or locking properly, which may compromise the security of the building in which the door is installed.

Such damage often ultimately requires the door to be repaired or replaced.

.5 This problem may be further exacerbated if the inner and outer sheets are exposed to significantly different temperatures. In such cases, one of the sheets may contract (for example the outer sheet due to being exposed to cold ambient temperatures in winter) while the other sheet simultaneously expands (for example the inner sheet due to being exposed to central heating). This may compound the resulting stresses on the structure, and hence exacerbate the damage to the components of the 20 door, including warping or bowing of the aluminium sheets themselves.

It is an object of the present invention to address the foregoing problems with the prior art, or at the very least to provide the public with a useful choice.

All references, including any patents or patent applications that may be cited in this specification are

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018 hereby incorporated by reference. No admission is made that any such reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications may be referred to herein, this reference does not 5 constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of including, but not limited to.

.0 Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION

According to one aspect of the invention, there is provided an insulated metal door, comprising:

a plurality of metal panels laterally spaced from one another, including a first outer panel and a .5 second outer panel;

an insulating layer disposed between an adjacent pair of the metal panels; and a bonding means connecting the adjacent pair of the metal panels, characterised in that the bonding means is resilient.

According to another aspect of the invention, there is provided a kit set for an insulated metal door, comprising:

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018 a plurality of metal panels configured to, in use, be laterally spaced from one another, including at least a first outer panel and a second outer panel;

an insulating layer configured to, in use, be disposed between an adjacent pair of the metal panels; and a bonding means configured to, in use, connect the adjacent pair of the metal panels, characterised in that the bonding means is resilient.

The invention is an improved metal door that includes an insulating layer to minimise or prevent unwanted ingress or loss of heat. The components of the door of the present invention are .0 specifically configured to be resilient, and / or are resiliently connected to one another. This means that expansion or contraction of a given component of the door (especially the outer panels) is substantially confined to that component. The other components of the door remain substantially stationary and unstressed. The door may therefore be less prone to temperature-related damage or failure.

It will be understood that the present invention has particular application to insulated aluminium doors, which are commonly used in buildings.

The use of aluminium is preferred due to the relative ease with which aluminium can be worked; in particular, its suitability to manufacturing processes such as extrusion, machining and pressing which may be involved in forming the panels of the present invention. Furthermore, aluminium is able to 20 withstand sufficiently high temperatures (in the region of 200°C) to enable the panels to be powdercoated, which is a common finishing treatment.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

Accordingly, the metal panels preferably comprise aluminium panels and reference to this effect shall now be made throughout the remainder of this specification.

However, this is not intended to be limiting. It will be appreciated that the present invention may also have application to doors formed from other metals which have relatively high thermal 5 conductivity and are prone to expansion and contraction due to changes in temperature.

A panel should be understood to mean a flat sheet, preferably rectangular in plan view and which is the typical shape of a door. Thus, a panel has an elongate dimension and a width dimension.

The plurality of aluminium panels should be understood to be orientated such that their elongate dimensions are substantially vertical in use. In use, the door will be hinged to the door frame with .0 which it is to be used along an edge of the elongate dimension.

The plurality of aluminium panels forming the door are preferably substantially parallel to one another in use.

The door includes at least a first outer panel and a second outer panel. Each panel will be understood to have two sides or faces (the interior and exterior surfaces) as well as opposing pairs of .5 edges.

Outer panels should be understood to mean those which define the overall external structure and dimensions of the door, that is to say, one side of each panel forms the exterior or external surface of the door, i.e. the surfaces which are exposed to the elements in use and which may be directly contacted by a user. The other side forms the interior or internal surface of the panels.

In embodiments in which only two panels are present in the door, one side of each panel forms the external surfaces. As the panels are arranged substantially parallel to each other, the other sides, i.e. the interior surfaces, face each other in use.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

However, in other embodiments, additional panels may be present, interspersed between the outer panels. These additional panels may be thought of as inner panels. In these embodiments, the interior surface of the outer panels face the exterior surfaces of the inner panel.

In some embodiments of the invention, an additional coating or finishing layers may be applied to the first and / or second outer panel. For example, a coat of paint, varnish or similar finishing material may be applied to the exterior surface of the first and / or second outer panel.

Alternatively, or in addition, an additional layer or skin of material may be applied to the exterior surface of the first and / or second outer panel, such as for decorative purposes. The skin may be formed from a rigid, semi-rigid or flexible material, such as a thin sheet of metal or a suitable plastics .0 material. The skin may be patterned, textured or moulded as desired for aesthetic appearances.

Preferably in this embodiment, the skin has a thermal co-efficient of expansion that corresponds to that of the panel to which it is applied.

The exterior surface of the first and / or second panel may comprise attachment means configured to enable attachment of the skin.

.5 In a particularly preferred embodiment, the attachment means are provided by a groove(s) disposed on the exterior surface of the first and / or second panel, and configured to be complementary to a corresponding groove(s) on the skin. In use, the respective grooves may be fitted together. This may enable the skin to sit flush against the exterior surface of the first and / or second panel when the door is assembled.

In some embodiments, small plates of aluminium may be applied to the exterior surface of the first and / or second outer panel to provide additional structural integrity for the mounting of door hardware. For example, an aluminium plate may be provided to the top corner of the door, proximate the hinging edge, for attachment of a self-closer mechanism.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

In a preferred embodiment, the insulated metal door comprises two metal panels, which in this embodiment are also the first and second outer panel.

Reference will be made throughout the remainder of the specification to the door comprising two aluminium panels (a first and a second panel). However, this is not intended to be limiting and it will 5 be understood that in some embodiments the door may comprise further aluminium panels, i.e.

inner panels, disposed between the first and second outer panel.

Preferably, each of the first and second panels has dimensions corresponding substantially to the overall desired dimensions of the door. That is to say, the door is formed from two unitary panels.

However, this is not intended to be limiting. In other embodiments, the first and second panels may .0 be formed from a plurality of subassemblies. For instance, the first panel may be formed from an upper section and a lower section, or even from four or eight sections. The skilled person will readily envisage appropriate means by which such panels may be connected to each other to form the first and second panel. However, it will be appreciated that this may complicate manufacture and assembly of the door.

.5 Preferably, the panels are configured as extrusions of aluminium sheet. In particular, when assembled, the door preferably does not require transverse reinforcing elements between the first and second panels such as internal ribbing. This may be achieved by selecting panels having appropriate dimensions and / or structural properties.

For instance, the panels may have a honeycomb cross-section, or may have a corrugated cross20 section comprising linear flutes formed by extrusion or rolling and covered by a flat exterior skin. The skilled person may envisage other suitable configurations for the panels.

It will be understood that the aluminium panels are parallel to and laterally spaced from one another, such that they do not directly contact one another in use.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

Preferably, a threshold spacing is maintained between adjacent panels in use to prevent the panels from coming into contact with each other. More preferably, the threshold spacing is at least 3mm, and, in some embodiments, may be greater than this.

Preferably, the threshold spacing may be provided by the insulating layer and / or the bonding layer, 5 which are disposed between adjacent panels.

In a particularly preferred embodiment, the bonding layer provides the threshold spacing, as discussed further below. As also discussed further below, depending on the desired threshold spacing the bonding layer may need to be adapted to accommodate a spacer.

The insulating layer should be understood to be a layer that acts as a thermal break between the .0 aluminium panels to prevent or minimise conductive heat transfer from one panel to another.

Preferably, the insulating layer is formed from a material having relatively low thermal conductivity. In particular, the thermal conductivity of the insulating layer is preferably relatively significantly lower than that of the aluminium panels.

Preferably, the insulating layer is resilient, i.e. able to be deformed to an extent but return to its .5 original shape with little or no loss of structural integrity.

Preferably, the insulating layer is formed from plastics foam such as polyurethane or polyvinyl chloride. More preferably, the insulating layer is formed from polymeric closed cell foam such as STYROFOAM™. Such material is lightweight, cost effective and easily sourced.

The inventor has found that a particularly effective insulating layer for use with the invention is provided by the SOFTLON™ 3000 polyolefin foam, which has a preliminary insulating value of

0.034W/m²K. However, this is not intended to be limiting and persons skilled in the art will readily identify other materials suitable for use as the insulating layer.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

Preferably, the insulating layer is disposed across substantially the entire inner surface of the first and second aluminium panels thus substantially filling the space between them (although it will be appreciated that appropriate space must be left for the bonding means, discussed below). This may maximise the efficacy of the insulating layer at minimising conductive heat transfer through the 5 door. However, in some embodiments the insulating layer may be disposed across only a portion of the surface area of the first and second aluminium panel.

Preferably, the insulating layer is provided by a single sheet of insulating material. This may be conducive to the ease of manufacture and assembly of the invention, as well as its insulating efficacy.

.0 However, in some embodiments the insulating layer may be provided by a plurality of smaller sheets of insulating material. These may be arranged between the first and second aluminium panels such that the upper sheets of insulating material are supported by those below them. Alternatively, in some embodiments the first and / or second aluminium panels may comprise components in the style of ledges or shelves atop which the insulating sheets may be placed.

.5 Preferably, the insulating layer abuts and may contact the interior surfaces of the first and second panels but is not directly connected to or otherwise secured thereto. This may allow the first and / or second panels to slide or otherwise move laterally relative to the insulating layer when the length and / or width of the first and / or second panels changes in response to temperature variations.

The bonding means should be understood to be resilient, i.e. able to be deformed to an extent but 20 return to its original shape with little or no loss of structural integrity.

Preferably, the bonding means is likewise disposed between the interior surfaces of the first and second panels.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

Preferably, the bonding means comprises adhesive surfaces for connecting and bonding to the first and second panels.

More preferably, the bonding means is provided by polymeric foam double-sided tape having a thickness of at least 3mm. It will be understood that double-sided tape has adhesive surfaces on 5 both its sides and thus is able to bond simultaneously to the first and second panels. The inventors have found that a polymeric foam double-sided tape having a thickness of 3.2mm is particularly well suited for use with the present invention. However, this is not intended to be limiting. For example, the bonding means could also be formed from multiple layers of polymeric foam double-sided tape.

Alternatively, the bonding means could be provided by a flexible filler or sealer, although this may .0 entail greater complexity in assembling the door, and / or the use of additional components such as backing tape. Flexible sealers may also not be as resilient as polymeric foam double-sided tape.

Preferably, the bonding means connects and bonds to a relatively small portion of the interior surface area of the first and second panel. More preferably, the bonding means connects the first and second panels proximate one elongate edge of the first and second panel. This may leave .5 maximal space for disposing the insulating means between the first and second panel.

For example, the bonding means may be configured as a plurality of substantially cuboid components arranged one above another proximate one elongate edge of the first and second panel, so as to intermittently connect the first and second panel.

However, this is not intended to be limiting. For example, in other embodiments the bonding means 20 may be configured as an elongate component having a length substantially equal to that of the first and second panel, and disposed proximate one elongate edge of the first and second panel. Other suitable configurations of the bonding means may readily be envisaged by the skilled person.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

In preferred embodiments, the bonding means may be configured to accommodate or provide a spacer, namely a component that increases the overall thickness of the bonding means and therefore the threshold spacing between the panels. In use, this may in turn allow the insulating layer to have a relatively greater thickness, which may increase its efficacy in thermally insulating the 5 door.

It will be appreciated that the bonding means could be applied to the surfaces of the spacer that would otherwise contact the panels.

The spacer may be nested within the bonding means, and may have a configuration complementary to that of the bonding means itself. For example, in embodiments wherein the bonding means has a .0 substantially cuboid configuration, the spacer may likewise have a substantially cuboid configuration.

In some embodiments, the spacer may be formed from a relatively resilient material, such as a closed-cell polymeric foam. Preferably, in such embodiments the spacer has a lesser resilience (i.e. a greater stiffness) than the bonding means itself. In other embodiments, the spacer may be formed .5 from a rigid material, for example aluminium.

Preferably, the door includes a cap linking the exterior surface of the first and second aluminium panels.

Preferably, the cap may abut the exterior surfaces of the first and second panel to form a clamp that defines the overall cross-sectional thickness of the door.

Preferably, the cap abuts the edges of the first and second panel. Accordingly, the cap preferably has an approximately U-shaped cross-section. It will be understood that the edge of the door is inserted into the recess defined by the arms of the U-shaped cross-section.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

Preferably, the cap is formed as an aluminium extrusion and is thermally broken. The use of aluminium for the cap may be advantageous as it may mean the cap has the same coefficient of thermal expansion as the aluminium panels. Aluminium is also able to withstand sufficiently high temperatures (in the region of 200°C) to enable the cap to be powder-coated, which is a common 5 finishing treatment for such components.

However, other materials meeting the above discussed parameters may also be suitable for the cap; specifically, materials having a coefficient of thermal expansion relatively similar to the aluminium panels, and which are able to be powder-coated.

Preferably, the cap may be disposed along at least a substantial portion of some or all of the edges .0 of the panels and may accordingly have an elongate configuration in the style of a U-beam. More preferably, there may be a single elongate cap for each edge of the panels.

An elongate cap may advantageously function as a seal, forming a barrier that prevents water, dirt or foreign matter from gaining access to the interior of the door as well as concealing the structure of the door from view for an aesthetically pleasing finish.

.5 In some embodiments, the door may also comprise one or more caps configured specially for mounting to a corner(s) of the door. These may be configured to abut two perpendicular edges of the panels simultaneously; such as, for example, the top edge and one of the side edges. However, this is not intended to be limiting and in other embodiments the caps mounted to each individual edge of the door may be configured and arranged to meet one another at the corners.

Preferably, the cap may be configured to accommodate ancillary components of the door. These may include, but are not limited to, components such as hinges, handles and / or locking mechanisms. The skilled person will readily envisage suitable means by which this may be achieved.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

The cap is preferably mounted to the first and second aluminium panels such that it is able to accommodate the expansion and contraction of the panels, as well as forming a watertight seal and also transferring forces applied to e.g. the handles or locks to the aluminium panels.

Preferably, the cap is mounted to the first and second aluminium panels using a flexible structural adhesive, such as one comprising Silyl Modified Polymer (SMP). The inventor has found that a particularly suitable adhesive is SABRE BOND™ SMP 60. However, this is not intended to be limiting and other appropriate adhesives may be used.

Preferably, the flexible structural adhesive is applied proximate the corners of the U-shaped crosssection of the cap, and therefore also proximate the exterior surfaces of the first and second panel .0 (more specifically, proximate the exterior corners of the panels).

In preferred embodiments, the components of the door may be configured and arranged so as to provide for air pockets between the first and second aluminium panels. For example, the bonding means may be spaced from the insulating layer so as to leave a gap between them. Similarly, the bonding means and / or insulating layer may be spaced from the cap, with the same effect.

.5 However, this is not intended to be limiting and in other embodiments the components of the door may sit flush against one another.

It will be understood that the insulating layer and bonding means are resilient; that is to say, capable of elastic deformation. This may ensure that deformation of the aluminium panels in response to temperature changes is absorbed and is not transferred to other components of the door.

As discussed above, the insulating layer is preferably disposed between but not connected to the first and second aluminium panel. As such, as the length and / or width of the panels incrementally changes during expansion or contraction, the panels are able to slide laterally with respect to the insulating layer.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

The bonding means is connected to the first and second panels. As such, it must have an appropriate resilience to enable it to deform along with the panels when their length and / or width changes during expansion or contraction. This ensures that a change in length and / or width of one of the aluminium panels is absorbed by the corresponding deformation of the bonding means, and is not 5 transferred to the other panel, or to other components of the door.

This in turn ensures that the other components remain stationary, and are not placed under stress as a result of the movement of the panel. In other words, a change in length and / or width of a given panel is effectively confined to that panel and does not affect the other components of the door.

.0 Furthermore, as discussed above the bonding means preferably defines the threshold spacing between the first and second aluminium panels.

In embodiments where the bonding means does not comprise a spacer, the threshold spacing may be provided by the configuration (in particular, the thickness) of the bonding means itself. For example, where the desired threshold spacing is 3.2mm, a bonding means having a thickness of .5 3.2mm may be selected.

As noted above, in embodiments where a greater threshold spacing is desired (such as in the region of 5mm), the use of a spacer may be advantageous. A resilient bonding means on its own having a thickness of, for example, 5mm may deform by an excessive amount in response to changes in the length and / or width of the aluminium panels. This may mean that the components of the door are 20 not sufficiently securely held together. A spacer nested within the bonding means and formed from either a rigid material or one of lesser resilience than the bonding means itself may provide the desired threshold spacing while also ensuring a robust connection between the components of the door.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

The adhesive connecting the cap, if present, to the aluminium panels is preferably also resilient; such as provided by a flexible structural adhesive. The adhesive may thereby absorb changes in the length and / or width of the panels and help prevent this movement from being transferred to other components of the door (including the cap itself).

In addition, in embodiments wherein the cap itself is formed from aluminium, the resilient adhesive may help to absorb temperature-related expansion and contraction of the cap itself.

It will be understood that the door may comprise further aluminium panels, disposed between the first outer panel and the second outer panel. It will further be understood that in such embodiments, an insulating layer and bonding means as described above may be disposed between .0 any pair of adjacent aluminium panels. Moreover, some embodiments may comprise a plurality of insulating layers and bonding means disposed between different pairs of adjacent aluminium panels.

The invention has been found to be relatively resistant to deformation arising from repeated thermal expansion. During testing, where heat is applied via an 8 kiloWatt infrared heater to one side of a door, formed in accordance with an exemplary embodiment of the invention, such that that .5 side of the door attains a temperature from 64° to 68° Celsius (the expected maximum range of operating temperature in New Zealand), the other side (the cold side) has been found to remain at a temperature between 28° to 31° Celsius.

Furthermore, the cold side of the door is substantially flat in all directions, with less than one millimetre of bowing. The structural integrity of the bonding means is uncompromised with no 20 delamination or failure of the adhesive used even after over 250 cycles of the door being heated and allowed to cool.

The invention has a number of advantages over conventional insulated metal doors, including:

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018 • providing a door that is effectively thermally insulated and hence minimises conductive heat transfer through the door; while also • providing a door that allows for the expansion or contraction of a given component while absorbing the resulting dimensional change of that component, thereby effectively confining the movement to that component and allowing the other components of the door to remain substantially stationary and free of applied stresses or forces; and thereby • providing a door that is robust and at reduced risk of damage or failure due to temperature changes.

At the very least, the present invention provides the public with a useful choice.

.0 BRIEF DESCRIPTION OF FIGURES

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 is a schematic showing a cross-section of an insulated metal door according to a first preferred embodiment of the present invention;

Figure 2 is a schematic showing a cross-section of an insulated metal door according to a second preferred embodiment of the present invention;

Figure 3 is a schematic showing a cross-section of an insulated metal door according to a third preferred embodiment of the present invention; and

Figure 4 is a schematic showing one side of an insulated metal door according to a fourth preferred embodiment of the present invention.

Throughout the drawings, like features are assigned a like numeral.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

DETAILED DESCRIPTION OF FIGURES

Figure 1 shows a cross-section of an insulated metal door (generally indicated by 100) according to a preferred embodiment of the present invention. The door (100) of this embodiment comprises two aluminium panels (102, 104) laterally spaced from one another, which in this embodiment also 5 comprise the first outer panel (102) and the second outer panel (104).

In this embodiment, the panels (102, 104) are formed as extrusions of aluminium sheet having a honeycomb cross-section (not shown in detail).

An insulating layer (106) is disposed between interior surfaces of the respective first (102) and second (104) panels. In this embodiment, the insulating layer (106) is formed from a flexible .0 polymeric closed-cell foam. The insulating layer (106) abuts but is not connected to the first and second panels (102, 104). This allows the panels (102, 104) to slide past the insulating layer (106) as their length and / or width changes due to heat-related expansion and contraction.

A bonding means (108), which in this embodiment is provided by flexible polymeric closed-cell foam double-sided tape, is disposed between and connects the first and second panels (102, 104). The .5 width of the bonding means (108) defines a threshold spacing between the first and second panels (102, 104).

The door (100) also includes a cap (110) linking the exterior surfaces of the first and second outer panels (102, 104). In this embodiment, the cap (110) has a generally U-shaped cross-section, including flanges (112) with inner faces that abut the exterior surfaces of the first and second outer 20 panels (102, 104), thereby defining the overall cross-sectional thickness of the door (100). The cap (110) also includes a side portion (114) that abuts the edges of the panels (102, 104).

In the illustrated embodiment, the cap (110) is connected to the panels (102, 104) using flexible structural or bonding adhesive (116) that has been applied to the inner corners of the cap (110),

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018 where the flanges (112) meet the cap's (110) side portion (114) such that the exterior edges of the first and second panels (102, 104) are retained to the cap. However, although not illustrated here, the adhesive is preferably applied to the inner faces of the flanges of the end cap.

In use, when, for example, the first panel (102) expands in response to an increase in temperature, its length increases, resulting in the first panel (102) moving to the left (as represented in Figure 1).

The first panel (102) is free to slide past the insulating means (106). The bonding means (108), which is connected to the first panel (102), deforms resiliently with the leftward motion of the first panel (102), thereby absorbing the motion. Accordingly, the displacement is confined to the first panel (102) and the bonding means (108), and is not transferred to the second panel (104). The second .0 panel (104) thereby remains substantially stationary and free of applied stresses.

The flexible structural adhesive (116) connecting the first panel (102) to the cap (110) compresses resiliently in response to the leftward motion of the first panel (102), absorbing the motion and minimising displacement of, or stresses upon, the cap (110).

Figure 2 shows a cross-section of an insulated metal door (generally indicated by 200) according to a .5 second preferred embodiment of the present invention. While substantially similar to that of Figure

1, in this embodiment the first and second outer panel (102, 104) comprise grooves (202) in their exterior surfaces.

A skin (204) applied to the exterior surfaces of the first and second outer panel (102, 104) for aesthetic purposes comprises complementary grooves (206) which fit into those grooves (202) of the 20 first and second outer panel (102, 104), allowing the skin (204) to sit securely against the exterior surfaces thereof. In some embodiments, not illustrated here, the width of the skin may be slightly less than the width of the panels; this creates a space or recess between the edges of the skin and the cap. During assembly of the overall door, this provides space for bonding adhesive to be applied as needed.

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

In the embodiment of Figure 3, the insulated metal door (generally indicated by 300) is again substantially similar to those of Figures 1 and 2. In this embodiment, the bonding means (108) comprises a spacer (302), which in this embodiment is formed from aluminium. The spacer (302) is nested within the bonding means (108), such that the resilient material (304) of the bonding means 5 connected to the first and second panels (102, 104), with the spacer (302) in between.

This allows the insulating layer (106) to have a relatively greater thickness without compromising the efficacy of the bonding means (108) in absorbing the lateral movement of the panels (102, 104) while at the same time ensuring the components of the door (300) are securely connected.

For instance, as the first panel (102) increases in length and hence moves leftward, the resilient .0 portions (304) of the bonding means (108) deform to absorb this motion. However, due to the rigid spacer (302) nested within the bonding means (108), the degree of deformation of the bonding means (108) is lesser than if the entire bonding means (108) were formed from the resilient material. As such, the bonding means (108), while absorbing the movement of the first panel (102), also maintains a secure connection between the components of the door (300).

.5 In Figure 4, one side of an insulated metal door (400) according to an alternative embodiment of the invention is illustrated, with certain internal components shown in dashed lines.

In particular, an additional aluminium plate (402) is positioned to a top corner of the door (400). This provides additional structural integrity to this area of the door which is important for it serves as a mounting point for an automatic closer (not shown). Additionally, to the hinging edge (404) of the 20 door (400), a length of T-section aluminium extrusion (a portion shown as dashed lines 406) is fitted to reinforce the capping element (not visible in this view but equivalent to 110 in embodiments of Figures 1 to 3) is affixed and secured using conventional adhesive. This improves the structural integrity of this edge which may be important for the mounting of hinging hardware (not shown) and supporting the overall weight of the door to the door frame (not shown).

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018

To the opposing edge (408) of the door (400), proximate the handle and locking hardware (not shown), the first (102) and second panels (not visible) are secured by three strips (shown as dashed lines 410a, 410b and 410c) of flexible polymeric closed-cell foam double-sided tape that has only been applied to one of the panels.

It will be seen that one strip (410b) is laterally offset from the other strips (410a, 410c); collectively this helps to reduce or prevent the structural integrity of the door (400) being compromised during the mounting and connection of hardware, such as locks or handles (not shown), to the door. If the screws (not shown) holding the hardware are overtightened, this has the potential to pull the outer panels (only one, 102, visible) together away from the capping (not shown) and creating a .0 depression in the panels. In some instances, this may lead to crushing of the insulating layer with a possible impact on its insulating properties. Offsetting the strips provides clearance for the hardware during installation and reduces the risk that the screws securing the hardware is overtightened.

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general .5 knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its

James & Wells ref: 307464AU / 47

2018208278 23 Jul 2018 attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the 5 scope of the appended claims.

Claims

1. An insulated metal door, comprising:

a plurality of metal panels laterally spaced from one another, including a first outer panel and a second outer panel;

an insulating layer disposed between an adjacent pair of the metal panels, wherein the insulting layer abuts an interior surface of the first and/or second outer panel but is not directly connected thereto; and a bonding means connecting the adjacent pair of the metal panels, characterised in that the bonding means is resilient and includes adhesive surfaces for connecting the first and second panels.

2. The insulated metal door of claim 1, wherein the first and /or second outer panel is configured as an extrusion of aluminium sheet.

3. The insulated metal door of either claim 1 or claim 2, wherein the insulating layer is formed from a material having a thermal conductivity lower than that of the first and /or second outer panel.

4. The insulated metal door of any one of claims 1 to 3, wherein the insulating layer is formed from plastics foam such as polyurethane or polyvinyl chloride.

5. The insulated metal door of claim 4, wherein the insulating layer is formed from polymeric closed cell foam.

James & Wells ref: 307464AU / 47

2018208278 25 Jul 2019

6. The insulated metal door of any one of claims 1 to 5, wherein the bonding layer provides a threshold spacing between the first and second outer panel which, in use, prevent the panels from coming into contact with each other.

7. The insulated metal door of claim 6, wherein the bonding means is disposed between an interior surface of the first and second outer panel.

8. The insulated metal door of any one of claims 1 to 7, wherein the bonding means is polymeric foam double-sided tape having a thickness of at least 3mm.

9. The insulated metal door of any one of claims 1 to 7, wherein the bonding means is a flexible filler or sealer.

10. The insulated metal door of any one of claims Ito 9, wherein the bonding means connects the first and second panel proximate one elongate edge of the first and /or second outer panel.

11. The insulated metal door of any one of claims 1 to 10, wherein the bonding means is configured to accommodate or provide a spacer disposed between the first and second outer panel.

12. The insulated metal door of claim 11, wherein the bonding means is applied to the surfaces of the spacer.

13. The insulated metal door of any one of claims 1 to 12, wherein the door includes at least one cap abutting an exterior surface of the first and second outer panel.

14. The insulated metal door of claim 13, wherein a cap is provided for a substantial portion of some or all of the edges of the first and / or second outer panel.

15. The insulated metal door of either claim 13 or claim 14, wherein the cap is formed as an aluminium extrusion.

James & Wells ref: 307464AU / 47

2018208278 25 Jul 2019

16. The insulated metal door of any one of claims 13 to 15, wherein the cap is mounted to the first and / or second outer panel using a flexible structural adhesive.

17. The insulated metal door of any one of claims 1 to 16, wherein a skin is attached to an exterior surface of the first and / or second outer panel.

18. The insulated metal door of claim 17, wherein the exterior surface of the first and / or second panel includes attachment means configured to enable attachment of the skin.

19. The insulated metal door of claim 18, wherein the attachment means are provided by a groove(s) disposed on the exterior surface of the first and / or second panel, and configured to be complementary to a corresponding groove(s) on the skin.

20. A kit set for an insulated metal door of any one of claims 1 to 19, comprising:

a plurality of metal panels configured to, in use, be laterally spaced from one another, including at least a first outer panel and a second outer panel;

an insulating layer configured to, in use, be disposed between an adjacent pair of the metal panels; and a resilient bonding means configured to, in use, connect the adjacent pair of the metal panels.

21. A method of manufacturing the insulated metal door as claimed in claim 1, wherein the method includes the steps of:

a. placing an insulating layer between an adjacent pair of metal panels; and

b. applying a bonding means to connect the adjacent pair of metal panels, wherein the bonding means is resilient and includes adhesive surfaces for connecting the first and second panels.