GB2095733A - Insulating frame member - Google Patents

Abstract

An insulating frame member for doors or windows has inner and outer metal frame sections with pairs of diverging cavities 7-10 in facing surfaces. An insulating insert 1, in the form of a plastics extrusion has a body-part and pairs of legs 3-6 which are forced apart and fit into the cavities of the facing frame sections, so that the insert forms an insulating bridge between inner and outer frame sections. <IMAGE>

Description

SPECIFICATION Improvements in or relating to insulating frame members This invention relates to insulating metal frame members, especially for windows and doors.

For at least 20 years it has been recognized as desirable to provide metal window and door frames, especially those fabricated from extruded metal sections, with an insulating section separating the inner and outer surfaces of the frame. This is in order to reduce heat flow between inside and outside surfaces of the frame and hence to minimize condensation problems on the inner surfaces of such frames, due to the said inner surfaces being much cooler than the temperature in the room concerned. The system of interposing a section of insulating material between internal and external metal frame surfaces is known colloquially as "thermal-break".

The problem of providing thermal-break sections in metal window frames has been tackled in various ways. Thus British patent specification No. 1,040,204 describes a system wherein a cavity in a hollow metal section is filled with an insulating material and then two parts of the metal forming the section are machined away so as to leave two sub-sections separated by insulating material. A similar system is described in U.S.

patent specification 3,204,324 where a metal bridge is machined away after filling a metal channel with polyurethane foam.

A different approach to providing "thermalbreak" sections is described in, for example, German patent specification 962,017 which describes the use of a "press-in" or "snap-in" plastics spacer interposed between two separate metal sections forming the inner and outer parts of the frame. Such a spacer normally has deformable integral lugs or projections which can be forced into recesses in the metal frame-sections to provide a reasonably firm joint between metal and plastics sections. Similar approaches using pressin or snap-in plastics sections are described in U.K.

patent specifications 2,048,350 and 2,049,775.

The problem of providing efficient and easily assembled "thermal-break" frame sections has exercised inventive minds for many years.

One of the problems associated with the pressin or snap-in approach is one of rigidity. It is difficult to devise a snap-together system which allows the metal parts connected together to be insulatingly separated and yet rigidly held apart, with sufficient precision, in the desired configuration for use in a window frame.

We have now devised a system of insulatingly separating inner and outer frame members which not only allows an adequate thermal break to be formed but also provides considerable rigidity in the assembled structure.

This invention consists in an insulating frame member comprising inner and outer metal frame sections, the facing surfaces of both inner and outer sections being provided with pairs of diverging cavities, the cavities of each pair being separated by a wedge-shape tongue, together with an insert of resilient insulating material having a body portion and two projections, each in the form of a pair of legs, the said legs being adapted to be urged apart by the tongue and to fit closely into the cavities of the said metal sections, whereby on assembly the insert forms an insulating spacer to separate inner and outer frame sections.

Preferably the legs of the insert and the corresponding cavities are provided with complementary serrated surfaces.

Preferably the insert is made up of two identical sections with inter-fitting tongues and grooves and a leg of each pair integrally formed with each section.

Preferably the insert is in the form of a pair of identical extrusions of plastics material, mounted back to back.

Preferably at least two inserts are used to separate adjacent inner and outer frame surfaces so as to form a "box-section" in which the plastics inserts are incorporated in opposite sides of the "box".

The invention will be further described by reference to the accompanying 3 figures of diagrammatic drawing in which: Figure 1 shows a section through a plastics insert according to the invention and how it cooperates with recesses in inner and outer frame sections.

Figure 2 shows the make up of a plastics insert according to the invention.

Figure 3 shows the use of such inserts in forming spacers between inner and outer metal window frame members.

With reference to Figure 1, the spacer insert 1, made of resilient plastics material, is composed of two identical halves, 1 a and 1 b, assembled backto-back. The insert 1 has pairs of legs 3, 4 and 5, 6 at opposite ends thereof and these fit into recesses or cavities 9, 10 and 7, 8 respectively in the metal sections 2 and 3. The cavities 9, 10 and 7, 8 diverge from one another and are separated by means of the wedge-shaped metal sections 11 and 12. As will be seen from Figure 1 both cavities and legs have complementary serrated surfaces which are adapted to inter-engage.In order to join the sections 2 and 3 together the legs of the insert are forced into engagement with the V-shaped wedges 11 and 12, the legs are spread apart and forced into cavities 7, 8 and 9, 1 0. The serrated edges on the legs then engage with complementary inner surfaces of the cavities and lock into place in those cavities. Thus a composite section is made up with the metal sections 2 and 3 separated by insulating insert 1.

With reference to Figure 2, the insert 1 is assembled by fitting 1 a against 1 b in back-to-back relationship with tongues 1 c and id fitting into corresponding grooves in the opposite half of the insert.

With reference to Figure 3, a section through a double-giazed window frame unit is shown.

External metal frame sections are shown as 13, 14, 15 and internal frame sections at 16, 17, 18 and 19. These are separated by insulating inserts marked 1 so that all external frame members are separated from internal frame members either by an insulating insert 1 or a double thickness of glass 20, 21 with an air-gap 22 between them.

This leads to extremely good thermal insulation between the inner and outer surfaces of the window frame, coupled with a very rigid construction due to the formation of box-sections between 16,1,13 and 1 and 19,1,15 and 1.

Claims (7)

1. An insulating frame member comprising inner and outer metal frame sections, the facing surfaces of both inner and outer sections being provided with pairs of diverging cavities, the cavities of each pair being separated by a wedgeshaped tongue, together with an insert of resilient insulating material having a body portion and two projections, each in the form of a pair of legs, the said legs being adapted to be urged apart by the tongue and to fit closely into the cavities of the said metal sections, whereby on assembly the insert forms an insulating spacer to separate inner and outer frame sections.

2. An insulating frame member as claimed in claim 1 wherein the legs of the insert and the inner surfaces of the cavities are provided with complementary serrated surfaces.

3. A frame member as claimed in claims 1 or 2, in which the insulating insert is made up of two identical sections, having inter-fitting tongues and grooves, and a leg of each pair integrally formed with the body portion.

4. A frame member as claimed in claim 3 wherein the insert is in the form of a pair of identical extrusions of plastics material mounted back to back.

5. An insulating frame member as claimed in claim 1, wherein at least two inserts are used to separate adjacent inner and outer frame surfaces so as to form a box-section, in which the insulating plastics inserts are incorporated in opposite sides of the box.

6. An insulating frame member substantially as hereinbefore described with reference to Figures 1 and 3 of the accompanying drawings.

7. An insulating insert for a frame member substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.