GB2124688A

GB2124688A - Insulated frame member

Info

Publication number: GB2124688A
Application number: GB08319961A
Authority: GB
Inventors: Patrick William Pinnington
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-07-23
Filing date: 1983-07-25
Publication date: 1984-02-22
Also published as: GB2124688B; GB8319961D0

Abstract

An elongate window or door frame member incorporating a thermal break comprising inner and outer portions 10, 11 connected by first and second spaced parallel channels 14, 17 having their sides facing away from one another. Each channel is formed with a longitudinal gap in the bottom wall 16, 19 thereof and contains a body of solidified thermally-insulating material, the gap in the bottom of at least one channel being closed, before introduction of the thermally-insulating material therein, by a strip 20 of thermally- insulating material which is shaped to inter-engage with the channel in such a manner as to locate the strip positively within the channel. <IMAGE>

Description

SPECIFICATION An elongate frame member incorporating a thermal break and methods of making such a member The invention relates to elongate frame members incorporating a thermal break and particularly, but not exclusively, to door or window frame members formed from extruded aluminium.

It is well known to provide a thermal break between the inner and outer surfaces of such members to minimise heat transfer between the inner and outer surfaces. A common and widely used method of forming such a thermal break is to connect inner and outer portions of the frame member by a channel the open side of which faces towards one side edge of the member. The channel is filled with a thermally-insulating material, which is normally in the form of a synthetic resin which is poured in liquid form into the channel and then cured. A gap is then cut in the bottom wall of the channel along the length thereof so that the cured synthetic resin provides the sole connection between the inner and outer portions of the frame member, thus providing the necessary thermal break. The cutting of the gap in the bottom wall of the channel is referred to as "debridging".

In some forms of frame member, however, such as hollow box-section frame members, a single body of thermally-insulating material does not provide a sufficiently rigid connection between the inner and outer portions of the frame member and it is necessary to provide to spaced thermal breaks connecting the inner and outer portions. In order to enable the two channels to be filled, the open sides of the channels must face away from one another towards opposite side edges of the member. The channels may then be filled in succession. However, it will be appreciated that this gives rise to problems in cutting the gaps in the bottom walls of the channels, since once the channels have been filled with thermally-insulating material the bottom walls thereof are inaccessible from outside the section.

Hitherto, this problem has been solved by filling one channel with thermally-insulating resin, and then cutting through the bottom walls of both channels simultaneously by passing a cutter into and through the unfilled channel to reach the bottom of the filled channel. With the infilled channel uppermost, a flexible strip of thermally-insulating material of suitable width is then laid along the bottom of the unfilled channel so as to cover the gap in the bottom wall thereof. The channel may then be filled with thermally-insulating resin which is then cured to complete the second thermal break.

Such method has severe disadvantages. Since the flexible strip of thermally-insulating material is simply laid along the bottom of the channel, there is a risk that it will be correctly positioned and that it will permit the resin to leak around the strip and through the gap in the bottom wall of the channel. This may cause incomplete filling of the channel, impairing the strength of the finished section.

More importantly, before the second channel is filled the inner and outer portions of the member are connected solely by the first thermal break, which will necessarily be located towards one side edge of the member. Consequently distortion of the frame member can occur before and during the filling of the second channel, due to lack of rigidity in the frame member. The filling of the second channel and completion of the second thermal break locks the two parts of the frame member together again but they may be locked together in a distorted position and this can result, for example, in a frame member where the inner and outer surfaces are not exactly parallel.

The present invention sets out to provide an elongate frame member incorporating a thermal break, and methods of manufacturing such a frame member, in which these advantages are overcome.

According to the invention there is provided an elongate frame member incorporating a thermal beak wherein the frame member comprises innner and outer portions connected by first and second spaced parallel channels, each channel being formed with a longitudinal gap in the bottom wall thereof and containing a body of solidified thermally-insulating material, the gap in the bottom of at least one channel being closed, before introduction of the thermally-insulating material therein, by a strip of thermally-insulating material which is shaped to inter-engage with the channel in such a manner as to locate the strip positively within the channel.

Since the strip is located positively within the channel, rather than being simply laid on the bottom of the channel as in the known arrangements, there is no risk of the strip being incorrectly located and permitting leakage of the thermally-insulating material where this is introduced in liquid form. Furthermore, the positive location of the strip holds the two portions of the frame member in the correct relative location while the thermally-insulating material is introduced so that there is no distortion of the frame member.

The channel and the longitudinal edges of the strip may be provided with inter-engaging formations which are a snap-fit so as to locate the strip positively within the channel. For example, the longitudinal edges of the strip may be formed with longitudinal recesses which snap over longitudinal projections on opposite sides of the gap in the channel. Said longitudinal projections may be provided on the side walls of the channel Preferably the strip of thermally-insulating material is substantially rigid across the main width thereof so as to support the frame member against both inward and outward distortion.

As mentioned above, the invention is particularly applicable to hollow elongate frame members having spaced inner and outer faces connected by spaced side faces, the channels forming at least part of the side faces respectively of the member.

A first and preferred method of manufacturing an elongate frame member according to the invention comprises initially forming the member without said gaps in the bottom walls of the channels, introducing the body of thermally-insulating material into said first channel, forming the gaps in the bottom walls of both channels by passing a cutter into the second channel and cutting through the bottom wall thereof to reach the bottom wall of the first channel and cut said gap therein, fitting the elongate strip within the second channel to close the gap formed in the bottom wall thereof by the cutter, and introducing the body of thermally-insulating material into the second channel.

Alternatively, the frame member may be manufactured by initially forming the member with the gap in the bottom wall of the second channel but without the gap in the bottom wall of the first channel, introducing the body of thermally-insulating material into said first channel, forming the gap in the bottom wall of the first channel by passing a cutter into the second channel and through the gap pre-formed in the bottom wall thereof to reach the bottom wall of the first channel and cut said gap therein, fitting the elongate strip within the second channel to close the pre-formed gap in the bottom wall thereof, and introducing the body of thermallyinsulating material into the second channel.

Afurther alternative method of manufacturing the member comprises intially forming the member without said gaps in the bottom walls of the channels, forming the gap in the bottom wall of the first channel, fitting the elongate strip within the first channel to close the gap in the bottom wall thereof, introducing the body of thermally-insulating material into the first channel and then repeating the above operations on the second channel in the member.

The following is a more detailed description of an embodiment of the invention, by way of example, reference being made to the accompanying drawing which is a section through a hollow elongate frame member, according to the invention, in the course of manufacture.

Referring to the drawing, the hollow frame member, which may be extruded from aluminium, comprises an outerface portion 10, an inner face portion 11, and side faces 12 and 13.

The side face 12 is formed with a first channel 14 having side walls 15 and a bottom wall 16. The other side face 13 is formed with a second channel 17 having side walls 18 and a bottom wall 19.

There is also provided a closure strip 20 formed from PVC or other suitable thermally-insulating material. The side edges of the strip 20 are provided with resilient formations 21 defining longitudinal recesses 22 which cooperate, in a manner to be described, with longitudinal projections 23 projecting inwardly from the side walls 18 of the second channel 17.

The frame member is initially extruded in the form shown in the drawing. It is then supported with the first channel 14 uppermost and the channel is filled, in known manner, with a liquid thermally-insulating resin which is then cured and solidifed.

Gaps are then sawn simultaneously in the bottom walls 16 and 19 of the two channels by passing a cutter into the second channel 17 and cutting through the bottom wall 19 thereof to reach the bottom wall 16 of the first channel 14 to cut a gap in that wall also. The gaps are cut along the whole length of the member. Then a piece of the closure strip 20, of suitable length, is introduced into the channel 17 and snapped onto the projections 23 which project from the side walls of the channel, thus bridging the gap which has been cut in the bottom wall 19 of the channel.

The strip 20 is comparatively rigid across the main width thereof and its positive engagement with the projections 23 firmly locates the side walls 18 of the channel the correct distance apart and thus ensures that the inner and outer face portions 10 and 11 of the member are precisely parallel.

The frame member is then orientated with the channel 17 uppermost and the channel is filled with resin in similar manner to the channel 14. The positive inter-engagement between the formation 21 on the strip 20 and the projection 23 within the channel ensures that there is no leakage of resin past the closure strip and no distortion of the frame member during this operation.

Thus, when the resin in the channel 17 has been cured the frame member is complete and rigid and provided with twin thermal breaks between the front and rear surfaces.

Instead of the gaps in the bottom walls 16 and 19 of the channel being cut simultaneously by a cutter, as described, the frame member may be initially extruded with the gap already pre-formed in the bottom wall 19 of the channel 17. In this case it is not necessary for the cutter to form the gap in the bottom wall 19 but merely necessary for it to pass through the pre-formed gap to reach the bottom wall 16 of the channel 14.

Alternatively, the gap may be formed in the bottom wall of one channel only by passing the cutter through the channel itself instead of through the other channel. The gap is then closed by the strip 20 before the channel is filled with resin. The operation is then repeated on the other channel.

It will be appreciated that the closure strip 20 may be formed from any suitable thermally-insulating material. The illustrated arrangement for providing positive location of the strip within the channel 17 is by way of example only and other inter-engaging formations may be employed.

The internal configuration of the channels 14 and 17 may be of any conventional form used in forming such thermal breaks, and the thermally-insulating material introduced into the channels may be of any suitable material.

Claims

1. An elongate frame member incorporating a thermal break wherein the frame member comprises inner and outer portions connected by first and second spaced parallel channels, each channel being formed with a longitudinal gap in the bottom wall thereof and containing a body of solidified thermally-insulating material, the gap in the bottom of at least one channel being closed, before introduction of the thermally-insulating material therein, by a strip of thermally-insulating material which is shaped to inter-engage with the channel in such a manner as to locate the strip positively within the channel.

2. An elongate frame member according to claim 1, wherein the channel and the longinal edges of the strip are provided with inter-engaging formations which are a snap-fit so as to locate the strip positively within the channel.

3. An elongate frame member according to claim 2, wherein the longitudinal edges of the strip are formed with longitudinal recesses which snap over longitudinal projections on opposite sides of the gap in the channel.

4. An elongate frame member according to claim 3, wherein said longitudinal projections are provided on the side walls of the channel.

5. An elongate frame member according to any of claims 1 to 4, wherein the strip of thermallyinsulating material is substantially rigid across the main width thereof so as to support the frame member against both inward and outward distortion.

6. An elongate frame member according to any of claims 1 to 5, wherein the frame member is a hollow elongate frame member having spaced inner and outer faces connected by spaced side faces, the channels forming at least part of the side faces respectively of the member.

7. A method of manufacturing an elongate frame member according to any of the preceding claims, comprising initially forming the member without said gaps in the bottom walls of the channels, introducing the body of thermally-insulating material into said first channel, forming the gaps in the bottom walls of both channels by passing a cutter into the second channel and cutting through the bottom wall thereof to reach the bottom wall of the first channel and cut said gap therein, fitting the elongate strip within the second channel to close the gap formed in the bottom wall thereof by the cutter, and introducing the body of thermally-insulating material into the second channel.

8. A method of manufacturing an elongate frame member according to any of claims 1 to 6, comprising initially forming the member with the gap in the bottom wall of the second channel but without the gap in the bottom wall of the first channel, introducing the body of thermally-insulating material into said first channel, forming the gap in the bottom wall of the first channel by passing a cutter into the second channel and through the gap pre-formed in the bottom wall thereof to reach the bottom wall of the first channel and cut said gap therein, fitting the elongate strip within the second channel to close the pre-formed gap in the bottom wall thereof, and introducing the body of thermally-insulating material into the second channel.

9. A method of manufacturing an elongate frame member according to any of claims 1 to 6 comprising initially forming the member without said gaps in the bottom walls of the channels, forming the gap in the bottom wall of the first channel, fitting the elongate strip within the first channel to close the gap in the bottom wall thereof, introducing the body of thermally-insulating material into the first channel, and then repeating the above operations on the second channel in the member.

10. An elongate frame member substantially as hereinbefore described with reference to the accompanying drawings.