GB2263129A - Panel with plastics frame - Google Patents

Abstract

A panel (1) comprises a substantially solid frame (5) comprising a plastics material and reinforcement means (9). The frame supports a pair of outer skins (17, 19). The solid frame may for example be of foamed plastics material with metal reinforcement or resin impregnated timber which preferably is laminated. The panel may be a door or other closure. <IMAGE>

Description

PANEL The present invention relates to a panel, especially but not exclusively, a panel intended as closure, for example a door, hatch, skylight or window.

British Patent Specification GB 2 236 346 A discloses a door comprising a rigid timber frame sandwiched between a pair of outer plastics skins and a thermally insulating and/or flame retardent material within the frame and retained by the skins. A disadvantage of such a door is that the expansion properties of timber and plastics are quite different, which can result in internal stresses and ultimately allow the ingress of water, causing the frame to rot.

A door comprising a pair of plastics skins mounted on a steel reinforced extruded thin-walled multi-chamber UPVC frame is disclosed in British Patent Specification GB 2 183 706 A. A door of such construction avoids the problems associated with the timber frame of the aforementioned known door but cannot be trimmed to size. This means that doors with such a construction must be tailor-made for each frame or opening. As a result, careful pre-measurements are needed, which is time-consuming and costly.

In a first aspect, the present invention provides a panel comprising a foamed plastics frame reinforced with metal, the frame being situated between a pair of outer plastics skins.

Especially, in a second aspect, the present invention provides a panel comprising a substantially solid frame comprising a plastics material and reinforcement means, the frame supporting a pair of outer skins.

Usually, substantially each frame member will comprise a substantially solid plastics material, most frequently all of the same such material.

Panels according to the present invention can enable a more precise fit when they are put in place on a building or other structure and are less prone to distortion and rotting, as compared with rigid timber framed assemblies. At the same time, they can be trimmed, unlike the construction using the thin-walled multi-chamber extruded frame.

Trimming is conveniently effected using standard tools such as an electric plane and the material may be worked with conventional woodworking tools such as a chisel.

At least one frame member of panels according to the present invention may comprise a substantially solid foamed plastics material. The substantially solid plastics material may for example be moulded onto a metal reinforcement. Alternatively, a longitudinal surface channel formed in at least one frame member may contain a metal reinforcement strip. The latter form of construction enables the product not only to be fabricated to domestic standards but also to industrial standards. Improved security in the form of resistance to forced entry is provided since hinges and locks can be screwed through to the metal strip. The plastics material may be, for example, medium density or high density foamed polyurethane or foamed polyvinyl chloride or foamed polystyrene.

Alternatively, the frames may be formed from resin-impregnated timber, the timber providing a reinforcement matrix to support the resin. For improved rigidity, such frames may be formed of laminated resin-impregnated timber. It is not absolutely necessary for the resin to permeate the entire body of the timber, but merely enough to give it the necessary strength and rigidity and, where appropriate, proof against rotting. Thus, resin impregnated timer has the machineability of natural untreated timer but is substantially maintenance-free. The resin used for the impregnation process may be, for example a phenolic resin.

Panels according to the present invention may be fixed non-movable items used in the fabrication of buildings etc, or they may be closures such as doors, hatches, skylights, windows or the like. As closures, they may lift in and out of a frame, or more preferably, be pivoted or hinged to enable them to be opened and closed.

The metal chosen for any metallic reinforcement will be chosen according to the intended application. For doors, aluminium is especially preferred. However, other metals such as steel, eg galvanised steel, may also be used. The term metal as used herein is to be taken to include metal alloys. Conveniently, the metal reinforcements are hollow in cross section to provide strength combined with lightness.

It is preferred that the frame be formed as a composite, ie the plastics material should be moulded on or around the metal reinforcement to adhere thereto. The skins may be attached to the frame by any appropriate means, for example with adhesive, screws, welding or using any other method or combination of methods which will be known to persons skilled in the art.

Preferably also, the skins are made from a thermoplastics material and may be co-extruded from a plurality of such materials to give the required combination of strength, W stability and any other desired properties.

The present invention also provides a method of manufacturing a panel, the method comprising forming a substantially solid frame comprising a plastic material, and securing skins to respective opposite faces of the frame.

More expecially, the present invention provides a method of manufacturing a panel, the method comprising forming a substantially solid frame comprising a plastics material and reinforcement means, and securing skins to respective opposite faces of the frame to be supported thereon.

In a preferred embodiment, the frame defines one or more cavities containing a thermally insulating and/or fire retardant material. This may be a suitable plastics material, for example cut to size from slabstock.

However, we prefer to inject the material into the cavities, for example using low density polyurethane foam. This also strengthens the overall structure.

Whilst side-pieces may be used to cover the edges of the frame after trimming if desired, the edges may be left exposed since they are not prone to weather damage as are the conventional timber frames.

When provided as a closure, eg a door, the panel may be mounted into an existing fixed outer framework (jamb) or into a purpose built low-maintenance framework.

Optionally, it may be supplied as a kit comprising the panel, outer framework elements and the necessary hinges/pivots, fastenings and the like.

The present invention will now be illustrated by the following description of a preferred embodiment and with reference to the accompanying drawing in which: Figure 1 shows a part cross-section through a door according to the present invention, together with a surrounding associated framework; and Figure 2 shows a cross-section through an alternative form of member for constituting the stiles and rails of the door shown in Figure 1.

As shown in Figure 1, a door panel 1 is mounted by means of hinges (not shown) in a surround 3. The surround may for example be constructed from the same material as the above frame.

The door panel comprises a frame 5 in which the stiles and rails comprise a composite structure of medium 3 density (typically 700 Kg/m ) polyurethane foam 7 moulded onto hollow aluminium reinforcements 9 having a generally 'box-girder' profile. The inwardly-facing surface 11 of the moulding has a cut-away portion 13 exposing one surface 15 of the aluminium.

A pair of skins 17, 19 are adhesively bonded onto the frame. The skins are made of Duradev (Registered Trademark) which is a triple-layer co-extruded thermoplastic material comprising an acrylic layer and two ABS layers. This material has exceptional surface finish, W stability, scratch resistance and impact strength. The edges of the skins are flush with the edge of the frame.

A cavity 21 is defined inside the frame and between the skins. This is strengthened by injection with low 3 density (typically 40 Rg/m3) polyurethane foam.

Figure 2 shows a cross-sectional view of an alternative form of member 25 which may be used for the stiles and rails of the door shown in Figure 1.

This is an elongate member comprising medium density extended polystyrene 27 in one longitudinal surface 29 of which is formed a substantially U-shaped shallow elongate channel 31. Where required, this U-shaped channel receives a solid steel reinforcement strip 33.

In another modification of this embodiment, the stiles and rails of the frame are formed instead of laminated resin impregnated timber.

In the light of this disclosure, modifications of the above-described embodiments, as well as other embodiments, all within the scope of the claimed invention will now be apparent to persons skilled in the art.

Claims (18)

1. A panel comprising a substantially solid frame comprising a plastics material and reinforcement means, the frame supporting a pair of outer skins.

2. A panel according to claim 1, wherein the frame comprises a substantially solid plastics material.

3. A panel according to claim 2, wherein the frame comprises a plurality of members and each member comprises the same substantially solid plastics material.

4. A panel according to claim 2 or claim 3, wherein the substantially solid plastics material is a foamed plastics material.

5. A panel according to any preceding claim, wherein the frame comprises stiles and rails at least one stile and/or rail comprising the reinforcement means, said reinforcement means comprising metal.

6. A panel according to claim 5, wherein the plastics material is moulded onto the metal reinforcement.

7. A panel according to claim 5, wherein the metal reinforcement is located in a channel formed in a surface of the at least one stile and/or rail.

8. A panel according to any of claim 1, wherein the frame is formed from resin impregnated timber.

9. A panel according to claim 8, wherein the resin impregnated timber is laminated.

10. A panel according to any preceding claim, wherein the skins are formed of a co-extruded multi-layer plastics material.

11. A panel according to any preceding claim, wherein the frame defines one or more cavities containing a thermally insulating and/or fire retardant material.

12. A panel according to any preceding claim, which panel is in the form of a door.

13. A kit of parts comprising a panel according to any preceding claim, outer framework and hinges/pivots and/or fastenings.

14. A method of manufacturing a panel, the method comprising forming a substantially solid frame comprising a plastics material and reinforcement means, and securing skins to respective opposite faces of the frame to be supported thereon.

15. A method according to claim 14, further comprising the step of introducing foam between the skins.

16. A panel substantially as hereinbefore described and with reference to the accompanying drawing.

17. A kit of parts for a panel substantially as hereinbefore described and with reference to the accompanying drawing.

18. A method of manufacturing a panel, the method being substantially as hereinbefore described and with reference to the accompanying drawing.