GB2084230A

GB2084230A - Thermal break sections

Info

Publication number: GB2084230A
Application number: GB8030367A
Authority: GB
Original assignee: Norcros Investments Ltd
Current assignee: Norcros Investments Ltd
Priority date: 1980-09-19
Filing date: 1980-09-19
Publication date: 1982-04-07
Also published as: GB2084230B

Abstract

A metal section, for example for use in door or window frames, has a thermal break formed by plastics material connecting two separate parts of the section. The two parts 8, 10 are formed separately. An edge of one of the parts is secured within a channel formed on the other of the parts by clips 16 spaced along the length of the channel and which prevent metal to metal contact from occuring between the two parts. The channel is then filled with liquid plastics material which, when solidified, connects the two parts of the section firmly together and provides the thermal break in the section. <IMAGE>

Description

SPECIFICATION Thermal break sections The present invention relates to sections incorporating a thermal break, for example for use as part of a door or window frame.

Frame members of door and window frames are frequently in the form of elongate metal sections, particularly of extruded aluminium or other lightweight metal. In order to reduce heat transfer between the part of the section which lies at the outside of the door or window and that part which lies at the inside, the section may be interrupted along its length so that the section consists of two parts, the two parts being connected by a material having low thermal conductivity, for example a plastics material. Such a construction is conventionally known as a thermal break.

One technique for producing a thermal break consists of initially forming the section with a channel in the zone in which the thermal break is to be formed so that the two parts of the section are connected by this channel. The section is then fed past a filling nozzle which directs plastics material into the channel to fill the cross-section of the channel, a suitable plastics material being foamed or solid polyurethane. The section is fed continuously past the filling nozzle of a filling machine so that the channel is filled with the plastics material along the length of the section.

When the plastics filling has solidified within the channel, the section is then fed past an appropriate cutter which machines away the base of the channel so that the two parts of the section remain connected by means of the plastics filling.

The technique of providing a thermal break by feeding a plastics material in liquid form into a channel in the section has advantages over other techniques for forming thermal breaks in that the process can be carried out substantially automatically and that the plastics, being initially in a liquid state can always fill the entire crosssection of the channel and therefore the channel can be of irregular shape or of any other appropriate shape according to design requirements.

The technique discussed above in which the base of the filled channel is machined away does, however, involve complicated handling when tubular or hollow sections are involved, in which a thermal break is required in each of two opposed walls or wall portions of the section. These difficulties will be apparent from the following discussion, with reference to Figure 1 of the accompanying drawings, of one previously proposed process for forming hollow or tubular sections with thermal breaks in its opposed walls.

The tubular section shown in Figure 1 comprises two separate sections, that is a main section 1 of inverted U-shape and a base section 2 which closes the open side of the main section.

Channels 3 for receiving the plastics material are formed on each of the two opposed sides of the main section 1 and lie inwardly of the section. The two channels 3 are initially filled with the plastics material in liquid form and when this has solidified, the base of each of the channels, as indicated at 4 in Figure 1, is machined away to provide the required thermal break. The bases 4 are machined away before the base section 2 is applied, in order to permit access of the machining cutters into the interior of the U-shaped main section 1. The base section 2 is then applied to the U-shaped main section having the two thermal breaks and is secured thereto in any appropriate way.

The novel features of the invention will be apparent from the following description, given by way of example only with reference to Figures 2 to 4 of the accompanying drawings. In these Figures: Figure 2 is a transverse cross-section through a hollow elongate section having two, opposed, thermal breaks, the section being taken in the zone of a securing clip; Figure 3 is a perspective view of a securing clip; and Figure 4 is a transverse cross-section similar to Figure 1 but taken at a position between two securing clips.

The hollow section shown in Figure 2 consists of two, initially separate, sections 8 and 10 of extruded aluminium or other suitable material. The section 10 is formed with two parallel channels 12 having inwardly-directed flanges 14 which define the longitudinal edges of the open side of the channel.

The section 8 has opposed, free, longitudinal edges 8 each of which is received in a respective one of the channels 12. The two sections 8 and 10 are initially assembled using resilient clips 16 of plastics material such as nylon or polypropolene. The clips 16 are located at intervals along the length of each of the channels 12, for example with a spacing of one metre between adjacent clips, with the free edges 8a of the section 8 being supported by the clips 16 out of contact with the side walls and base of the channels 12.

As shown in Figure 3, each clip 16 comprises a pair of opposed outwardly inclined walls 1 8 which can be resiliently deflected inwardly to enable the clip to be held within the channel by snap-in engagement beneath the inwardly directed flanges 14 at opposite edges of the open side of the channel. The width of the clip at its base is substantially equal to the internal width of the channel 12 so that the clip is an accurate fit within the channel. The clip 16 also has a pair of resilient lugs 20 which engage behind an enlargement formed along the free edge 8a of each side of the section 8 so as to positively retain and locate the free edge 8a.

The two sections 8 and 10 held in assembled relation by the plastics clips 16 are fed through a filling machine in which plastics material, such as foamed or solid polyurethane, is fed in liquid state simultaneously into each of the two channels 12.

When the plastics material solidifies, the two sections 8 and 10 are firmly secured together thereby, with the clips 16 being embedded within the solidified material. The solidified plastics filling and the plastics clips embedded therein collectively form the thermal break and it will be apparent that this has been achieved without the need for any metal machining operations subsequent to the filling operation. It will also be apparent that no subsequent joining operations are required to connect the two sections 8 and 10 because these sections are already connected by the plastics material which forms the thermal break.

The initial assembly of the two sections using the plastics clips is very straightforward as the two sections are simply in snap-in engagement with the clips and the clips accurately position the free edges of the upper section within the channels.

It will be apparent that the shape and configuration of the two sections may be different from that specifically illustrated. Also, instead of two longitudinal channels being formed on one section, one such channel may be formed on each section to receive a free longitudinal edge of the other section.

Although the invention has been particularly described in relation to the production of hollow or tubular sections with thermal breaks, it will be apparent that the invention is also applicable to the production of a single thermal break in any section of appropriate shape. The section is produced initially in two separate elongate parts, one of which is provided with a channel, and an edge of the other part is secured within the channel by means of clips prior to filling the channel with the plastics material. This again provides the advantages of avoiding the need for any subsequent metal machining operations.

Sections incorporating one or more thermal breaks as described may be used as frame members for door or window frames.

Claims

1. A method for producing an elongate metal section incorporating a thermal break comprising connecting two separate metal parts of the section by securing at least one elongate edge portion of one of said parts within a respective elongate channel of the other of said parts by clips spaced along the length of the channel to prevent metal to metal contact from occurring between said parts, and filling the or each channel with a solidifiable thermal insulating material to connect the two parts together when solidified.

2. A method according to claim 1, wherein the two parts when connected define a hollow section, the said other part comprises two said channels, said channels being parallel and facing in the same direction, and the said one part comprises two said edge portions each retained within a respective one of the channels.

3. A method according to claim 1 or claim 2, wherein the or each channel comprises a lip projecting inwardly from at least one side wall of the channel, and the clips are retained within the channel between the lip and the base of the channel.

4. A method according to any one of claims 1 to 3, wherein the clips retain the edge portion of the said other part by a snap-in engagement with, the edge portion.

5. A method for producing an elongate metal section incorporating a thermal break longitudinally of the section, comprising connecting two separate metal parts of the section by means of plastics clips which are engaged in a channel extending longitudinally of one of said sections and which prevent direct contact between the two parts, and filling the channel with solidifiable plastics material in fluid form whereby the clips are embedded within the plastics material and the plastics material when solidified provides a firm connection between the two parts.

6. A method according to claim 5, wherein the two parts, when assembled, define a hollow section and a respective said thermal break is provided in each of two opposed wall parts of the section, one of said parts including two said channels, said channels being parallel and facing in the same direction, and the other of said parts including two portions each extending longitudinally within a respective one of the channels and secured within the channel by means of the clips and plastics material within the channel.

7. A method according to claim 5, wherein the two parts, when assembled, define a hollow section and a respective said thermal break is provided in each of two opposed wall parts of the section, each of said parts including a said channel and a portion extending longitudinally of the part and secured within the channel of the other respective part by means of the clips and plastics material within the channel.

8. A method substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.

9. An elongate metal section for use in a door or window frame when produced by a method according to any one of the preceding claims.

10. An elongate metal section for use in a door or window frame, said section comprising two separate elongate metal parts interconnected by a thermal break comprising a channel in one of said parts, a portion of the other of said parts within said channel and retained out of direct contact with the walls of the channel by clips of a thermal insulating material, and plastics material filling said channel and embedding the said portion of the other part and the clips.

1 A section according to claim 9, wherein the section is hollow and two such thermal breaks are provided at opposite wall parts of the section.

12. A metal section substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.