GB2097889A

GB2097889A - Improvements in or relating to frames, particularly for windows

Info

Publication number: GB2097889A
Application number: GB8113474A
Authority: GB
Original assignee: Consort Aluminium Ltd
Current assignee: Consort Aluminium Ltd
Priority date: 1981-05-01
Filing date: 1981-05-01
Publication date: 1982-11-10
Also published as: GB2097889B

Abstract

In an extruded aluminium window frame there is provided a resilient C-shaped bracing element 23 extending across each mitred junction 22 between two adjacent frame members 10, 11, the element 23 being secured to each frame member at least in part by virtue of its resilient engagement therewith. The resilient engagement between the bracing element 23 and the frame members is such as to apply to said members forces in a sense to tend to close the mitred junction 23 between the members, so that not only does the bracing element provide a reinforcement to preventing opening of the mitred junction but it also exerts a positive force to maintain the junction closed. <IMAGE>

Description

SPECIFICATION Improvements in or relating to frames, particularly for windows The invention relates to frames, particularly for windows, of the kind comprising four elongate frame members connected together in rectangular configuration, the ends of adjacent frame members having abutting mitred surfaces. The invention is particularly, but not exclusively, applicable to windows where the frame members are formed from aluminium extrusions.

In this specification an "outer" surface of such a frame, or frame member, means a surface thereof which is visible when viewed at right angles to the general plane of the frame.

In a window, such a frame may be used either as the fixed frame of the window, or as the frame of the movable part of the window, referred to as the vent. Such frames may also be used in the construction of doors, door surrounds, ventilators and solid or glazed panelling, and the present invention is also applicable to frames for such purposes.

In a frame of the kind first referred to various means may be employed for connecting the mitred frame members together in rectangular configuration. In the case where the frame members are metal extrusions, for example, such means may comprise an L-shaped metal connector the respective limbs of which are inserted fully into the ends of longitudinal channels in the frame members and are then clamped to those members by deforming parts of the frame members to bite into the connector.

Although such an arrangement may hold the corners of the frame firmly together from a structural point of view, it is found in practice that, under stress and with use, there is a tendencyfor the mitre joints to separate slightly at the outer faces of the frame, particularly in cases where the outer face of each frame member is defined by a flange which is spaced from the connector and perhaps separated therefrom by a thermal break.

Separation of the mitred edges is most likely to occur when the frame is to be glazed, since in this case the forcing of glazing strips between the glazing panel and the outer flanges of the frame members tends to deform the flanges outwardly from the general plane of the frame, causing separation of the mitred end edges of those flanges.

This slight separation of the mitred joints of frames at their outer surfaces is unsightly and gives the incorrect impression that the frame is illfitting, and an object of the present invention is to prevent such separation of the mitred joints.

According to the invention, in a frame of the kind first referred to, there is provided a resilient bracing element extending across the mitred junction between two adjacent frame members, said element being secured to each frame member at least in part by virtue of its resilient engagement therewith. Since the bracing element is secured to the two frame members and extends across the junction between them, it serves to prevent or reduce separation of the mitred junction.

Preferably the resilient engagement between the bracing element and the frame members is such as to apply to said members forces in a sense to tend to close the mitred junction between the members. Thus, in such an arrangement, not only does the bracing element provide a reinforcement to prevent opening of the mitred junction but it also exerts a positive force to maintain the junction closed.

An elongate frame member for use in a frame of the kind first referred to will often be formed with a channel, the web of which forms at least part of an outer surface of the frame and is in mitred abutment with the web of a similar channel on the adjacent frame member. In this case a respective portion of the bracing element may be resiliently braced between the flanges of such channel so as to be secured within the channels, the part of the bracing element between said portions thereof extending across the junction between the webs.

The bracing element may be generally Cshaped, the free ends respectively of the C-shape each engaging one flange of an associated channel, intermediate portions of the bracing element engaging the other flanges of said channel. Conveniently the bracing element may comprise a circlip.

The invention includes within its scope a method of constructing a frame of the kind first referred to comprising the steps of connecting together two adjacent elongate frame members at right angles to one another, and resiliently connecting a bracing element to said frame members so as to extend across the mitred junction between them.

The following is a detailed description of an embodiment of the invention, reference being made to the accompanying drawing which is a perspective view of the inside of one corner of a window frame.

The window frame is constructed from elongate aluminium extrusions two of which are indicated at 10 and 1 1. Each extrusion comprises a front part 12 and a rear part 13 connected together in conventional manner by a plastics thermal break 14. The front part 12 is formed with a shallow channel section comprising a web portion 15 and side flanges 16 and 17. The outer surface of the web 1 5 forms part of one visible outer surface of the frame.

The other part 13 of each frame member is formed with a C-sectioned channel 18 and an outer flange 1 9 which provides the other visible outer surface of the frame.

The two frame members 10 and 11 have mitred ends and are connected together by means of a rigid L-shaped metal connector 20 the limbs of which are inserted into the ends of the channels 18 in the frame members. The connector 20 is formed with a transversely ridged surface and is secured within each channel 18 by deforming parts of the web of each channel 1 8 into engagement with the ridges.

The flanges 19 of the two frame members meet along a mitred junction 21 and the webs 15, at the opposite face of the frame, meet along a mitred junction 22.

As previously explained, the junction 22 in particular has a tendency to separate under stress and with use. This is due, to a large extent, to the presence of the thermal break 14 between the two parts of each frame member. Because of the presence of the thermal break the part 1 2 of each frame member is capable of flexing movement relative to the part 13 which is firmly held by the connector 20.

In the embodiment of the invention shown in the drawing a bracing element in the form of a circlip 23 is disposed within the shallow channels on the parts 12 of the frame members so as to extend across the junction 22. The circlip 23 is so dimensioned that when opened up, using a conventional circlip applying tool, it may be inserted into the position shown with its free ends bearing against the flanges 1 6 on either side of the junction 22, and its intermediate back portion bearing against the flanges 17. When the circlip is released from the applying tool it bears resiliently between the flanges 16 and 17 so as to force the two parts 12 together in a manner to tend to close up the junction 22.

The flange 16 of the channel on the part 12 is formed with an undercut, as indicated at 24, and the ends of the circlip are forced into this undercut, this serving to locate the circlip firmly in position.

A circlip of appropriate dimensions is chosen according to the dimensions of the frame members.

Although the invention has been described in relation to a particular form of aluminium window frame incorporating a thermal break, it will be appreciated that the principle of the invention is applicable to many different types of frame having mitred joints at their corner junctions. Although a circlip may be used for many types of frame member, as shown in the drawing, in some cases a specially designed bracing element may be required. The bracing element is preferably resilient and so designed as to apply a resilient force tending to close up the mitred junction, but in some cases the resilience of the bracing element may merely be for the purpose of securing opposite ends of the bracing element to the frame members. The bracing element then acts simply as a reinforcement and prevents opening of the junction by virtue of its resistance to bending rather than by applying a positive resilient closing force to the junction.

Claims

1. A frame, for a window or the like, of the kind comprising four elongate frame members connected together in rectangular configuration, the ends of adjacent frame members having abutting mitred surfaces, wherein there is provided a resilient bracing element extending across the mitred junction betwene two adjacent frame members, said element being secured to each frame member at least in part by virtue of its resilient engagement therewith.

2. A frame according to claim 1, wherein the resilient engagement between the bracing element and the frame members is such as to apply to said members forces in a sense to tend to close the mitred junction between the members.

3. A frame according to claim 1 or claim 2, wherein each elongate frame member is formed with a channel, the web of which forms at least part of an outer surface of the frame and is in mitred abutment with the web of a similar channel on the adjacent frame member, and wherein a respective portion of the bracing element is resiliently braced between the flanges of such channel so as to be secured within the channel, the part of the bracing element between said portions thereof extending across the junction between the webs.

4. A frame according to claim 3, wherein the bracing element is generally C-shaped, the free ends respectively of the C-shape each engaging one flange of an associated channel, intermediate portions of the bracing element engaging the other flange of said channel.

5. A frame according to claim 4, wherein the bracing element comprises a circlip.

6. A method of constructing a frame of the kind comprising four elongate frame members connected together in rectangular configuration, the ends of adjacent frame members having abutting mitred surfaces, the method comprising the steps of connecting together two adjacent elongate frame members at right angles to one another, and resiliently connecting a bracing element to said frame memebrs so as to extend across the mitred junction between them.

7. A method according to claim 6, wherein the resilient engagement between the bracing element and the frame members is such as to apply to said members forces in a sense to tend to close the mitred junction between the members.

8. A frame substantially as hereinbefore described with reference to the accompanying drawings.

9. A method of constructing a frame substantially as hereinbefore described with reference to the accompanying drawings.