GB2072296A

GB2072296A - Mitred frame joint

Info

Publication number: GB2072296A
Application number: GB8007925A
Authority: GB
Original assignee: Anglian Windows Ltd
Current assignee: Anglian Windows Ltd
Priority date: 1980-03-08
Filing date: 1980-03-08
Publication date: 1981-09-30
Also published as: GB2072296B

Abstract

A mitre joint between hollow-sectioned extruded frame side is secured by means of a device within the hollow sections and which comprises a clamping member (40) having opposed hooks (45) which are drawn into engagement with punched depressions (17, 27) in the outside walls (11, 21) of the hollow sections in order to clamp the frame sides (10 and 20) together. The clamping member (40) is forced into its clamping position by means of a securing screw (44) acting on a thrust member (50) which bears against the corner (32) formed within the hollow section by the inside walls (12, 22) of the hollow section. The screw (44) is socket-headed and is operated via a hole 18, 28 in the frame's corner and a hole 43 in the clamp 40. <IMAGE>

Description

SPECIFICATION Improvements in hollow-sectioned metal door and window frames Field of Invention This invention relates generally to door and window frames formed by hollow-sectioned metal extrusions, usually aluminium extrusions, and in particular to a securing device for clamping together two sides of such a door or window frame.

Background Metal framed doors and windows are generally formed with straight sides constituted by hollowsectioned metal extrusions, the ends of the extruded sides being mitred to abut at right angled corners of the frame. Clearly, securing means are necessary at the mitred corners in order to secure the sides of the frame together.

One known form of securing means consists of an L-shaped member which is located within the hollow section of the frame at a mitred corner.

This member substantially fills the hollow section, so that fixing screws can be screwed into the respective limbs of the L-member both inwardly through the outside walls of the hollow-sectioned frame sides and outwardly through the inside walls of said hollow-sectioned frame sides. This arrangement necessitates the use of jigs four drilling purposes, and involves considerable handling work, especially for the insertion, location and tightening of the fixing screws, which usually number at least eight at each corner.

Another known arrangement, which involves less handling work, involves a box-like insert having lugs on two right angled walls. This insert is located within the hollow section in the internal corner formed within the hollow section by the outside walls of two hollow-sectioned abutting frame sides so that the lugs are engaged in apertures in said outside walls. The insert is forced towards the internal corner, thereby to ensure tight engagement of the lugs in the outside wall apertures, by reaction against a Y-shaped thrust member which is housed within the box-like insert and is driven against the external corner formed within the hollow section by the inside walls of the hollow-sectioned frame sides.This known arrangement is tightened by means of a single fixing screw at each corner of the frame, but is disadvantageous in requiring accurately positioned lug-receiving apertures through the outside walls of the frame sides, and in requiring a chunky, relatively expensive insert which is deep enough to permit the thrust member housed therein to engage the external corner at the inside walls of the frame. The latter disadvantage is especially important in the case of door frames, wherein the hollow section can have a depth three or four times that of a window frame, which disadvantage can then only be minimised at the expense of providing the extruded frame sides with additional internal webs for engagement by the Y-shaped thrust member.

Object of the Invention It is an object of the present invention to provide a securing device for metal framed doors and windows which avoids the disadvantages of the known forms of securing means.

The Invention According to the present invention, there is provided a securing device for clamping together two sides of a hollow-sectioned metal door or window frame which are adapted to abut at a mitred corner, said device being adapted to fit within the hollow section of the frame at the mitred corner and comprising a thrust member having an inner end with angled end faces adapted to embrace the external corner formed within the hollow section by the abutting inside walls of the two hollow-sectioned frame sides, an internally screwthreaded clamping means for engagement with the abutting outside walls of the two hollow-sectioned frame sides in the region of the internal corner formed thereby within the hollow section and a securing screw extending through said clamping means to bear against the outer end of the thrust member, said clamping means having opposed hooks which, when the securing screw is driven inwardly through an access hole in the outside wall of the frame, are drawn into tight engagement with internal projections on the outside walls of the two frame sides in order to clamp the two sides of the frame together. According to a further aspect of the invention, there is provided a hollow-sectioned metal door or window frame having adjacent sides clamped together by the said securing device.

Further Features Preferably, the thrust member has a longitudinal median dimension between its inner and outer ends equal to at least one half of the internal diagonal dimension of the hollow section at the mitred corner. Thus, in the present invention, the thrust member is not required to be housed within the clamping means, and it can have a relatively long stalk or stem extending along the diagonal dimension of the hollow section. Consequently, the clamping means itself can be less bulky and expensive than the box-like insert used hitherto. In a preferred form, the clamping means comprises a recessed clamping member wherein an internally screwthreaded nut is keyed against rotation, the clamping member also being apertured into said recess for passage of and/or access to the securing screw.

The thrust member may assume any one of a number of constructions, such as a flat, hollow, wedge-shaped member having a corner embracing recess at its inner end. Preferably, however, the thrust member carries opposed wings for sliding engagement with internal ledges carried within the hollow section by the outside walls of the two frame sides, thereby providing for automatic location of the angled end faces of the inner end of said thrust member. Thus, in a preferred construction, the thrust member has a flat stem carrying the opposed wings at its outer end and angled corner-embracing flanges at its inner end.

The securing screw may conveniently comprise an Allen socket grub screw, while the outer end of the thrust member preferably has a seating for engagement by the end of said securing screw.

With reference to the door or window frame, in a preferred arrangement, the internal projections for engagement by the hooks on the clamping means are constituted by punched depressions in the outside walls of the hollow-sectioned frame sides. However, the internal projections may alternatively be constituted by partly punched out tabs or the like.

The access aperture to the securing screw may conveniently be formed by cooperating partial apertures in the outside walls of the frame sides at the abutting ends thereof.

Brief Description of Drawings A practical arrangement of securing device in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which.~ Figure 1 is a transverse section through one hollow-sectioned side of a metal door frame, looking towards 3 mitred corner of the frame adapted to receive the securing device of the invention; Figure 2 is a section parallel to the plane of the door frame, showing a preferred securing device fitted in position to clamp two sides of the frame together; and Figure 3 shows a modified thrust member for the securing device.

Description of Embodiment In Figure 1, the reference 10 denotes an extrusion, e.g. of aluminium, forming one hollowsectioned side of a metal door frame. The extruded frame side 10 has an outside wall 1 an inside wall 12, and front and rear walls 13 and 14 defining the front and rear faces of the door.

Internal webs 15 form ledges within the hollow section 1 6, adjacent the longitudinal edges of the outside wall 11.

The extruded frame side 10 has a mitred right angled corner at which it abuts a similar extrusion 20, usually of different length, constituting an adjacent side of the door frame. The extruded frame side 20 lies below the plane of the paper in Figure 1, extending from the mitred corner to the right. Its outside waii is referenced 21, and its internal ledges corresponding to the webs 15 are referenced 25.

The frame side 10, and likewise the frame side 20, have a pair of rectangular wedge-like depressions 17 (27 in the frame side 20) punched into the outside wall 1 1 (or 21) a short distance from the mitred corner. The position of these punched depressions 17 and 27 relative to the corner edge is clearly shown in the case of the frame side 20, and their shape will be more clearly apparent from Figure 2.

In addition, the end edges of the outside walls 11 and 21 which abut at the mitred corner are formed with partial apertures 18 and 28 (only the partial aperture 28 is visible in Figure 1), which cooperate to form a complete aperture providing screwdriver access to the interior of the hollow section 16 along a diagonal axis 30 (see Figure 2) at the mitred corner.

The securing device of the invention, in use to clamp together the frame sides 10 and 20, is shown in Figure 2, which in relation to the said extrusions 10 and 20 employs the same references as Figure 1.

This securing device comprises a clamping member 40, of the cross-sectional shape shown in the drawing, which has a recess 41 wherein an internally screwthreaded nut 42 is keyed against rotation. The clamping member 40 also has an aperture 43 permitting screwdriver access, through the aperture 18, 28, in the outside wall 11 21 of the door frame, to a securing screw 44 engaged in the nut 42 and extending inwardly of the hollow section 1 6 of the door frame. The screw 44 is conveniently an Allen socket grub screw. In position within the hollow section 16, the axis of the clamping means constituted by the clamping member 40 and nut 42 is aligned with the diagonal axis 30 at the mitred corner of the door frame.Also aligned with the axis 30 is the stem 51 of a thrust member 50, which has wings 52 at its outer end and mutually perpendicular webs 53 at its inner end. the said parts of the thrust member 50 extend across substantially the full width of the hollow section in the direction normal to the sectional plane of Figure 2. The wings 52 at the outer end of the thrust member 50 slidingly engage the internal ledges 15 and 25 of the respective frame sides 10 and 20, thus providing for automatic location of the angled webs 52 at the inner end of the thrust member around the external corner 32 formed within the hollow section 1 6 by the inside walls 12, 22 of the frame sides 10 and 20.

For clamping the two frame sides 10 and 20 together, the securing screw 44 is screwed inwardly to engage the outer end of the thrust member 50, conveniently at a small seating 54 provided in the outer end face of said member.

Further tightening of the screw 44 forces the thrust member 50 into tight engagement with the external corner 32, and thereby by reaction forces the clamping member 40 towards the internal corner 34 formed by the outside walls 1 1. 21.

In accordance with the invention, the clamping member 40 is provided with opposed hook-like parts 45. When the securing screw 44 is tightened, these hook-like parts 45 are drawn into tight engagement with the punched depressions 17 and 27 projecting inwardly from the outside walls 11 and 21 of the frame sides 10 and 20, thereby to clamp the two frame sides together.

The hook-shaped parts 45 may be formed across substantially the full width of the clamping member 40 (in the direction normal to the sectional plane of Figure 2) or alternatively two opposed pairs of hooks may be provided, one pair of hooks on one side of the clamping member 40 to engage the punched depressions 1 7 of the frame side 10 and one pair of hooks on the other side of the clamping member to engage the punched depressions 27 of the frame side 20.

The substantial le#ngth of the stem 51 of the thrust member 50, equal to at least 50% of the diagonal dimension of the hollow section 16 on the axis 30, and which length of the stem can be increased for hollow sections of increased depth, enables a relatively small, lightweight and inexpensive clamping member 40 to be employed, as compared to the bulky box-like insert which has been used hitherto. In addition, a firm and positive clamping action is achieved without the necessity to drill or otherwise form holes in the outside walls of the frame. Comparatively, the punched depressions can be formed easily and inexpensively, without creating possible sealing difficulties. With the arrangement according to the invention, sealing is desirable only at the aperture 1 8, 28 provided for screwdriver access.This aperture is preferably plugged, in a manner permitting subsequent removal of the plug if access to the securing device within the hollow section should be required for maintenance purposes at a later time.

Alternative constructions of thrust member are possible, as instanced by the member 60 shown in Figure 3, which has a hollow, flat, wedge-like form. Again, the inner end of the thrust member 60 has mutually perpendicular end faces 62 to embrace the external corner 32-formed by the inside walls 1 2 and 22 of the hollow-sectioned frame sides, but the wings for engaging the internal ledges 15 and 25 are omitted. The thrust member 60 is therefore not self-locating like the member 50, but this is a relatively minor disadvantage when positioning the securing device prior to tightening, and is not detrimental to the clamping effect achieved once the securing screw has been tightened.

It will also be apparent that the clamping member can take various constructional forms incorporating opposed hook-like parts and that, if desired, the securing screw may engage directly in such a modified clamping member.

Claims

1. A securing device for clamping together two sides of a hollow-sectioned metal door or window frame which are adapted to abut at a mitred corner, said device being adapted to fit within the hollow section of the frame at the mitred corner and comprising a thrust member having an inner end with angled end faces adapted to embrace the external corner formed within the hollow section by the abutting inside walls of the two hollowsectioned frame sides, an internally screwthreaded clamping means for engagement with the abutting outside walls of the two hollowsectioned frame sides in the region of the internal corner formed thereby within the hollow section and a securing screw extending through said clamping means to bear against the outer end of the thrust member, said clamping means having opposed hooks which, when the securing screw is driven inwardly through an access hole in the outside wall of the frame, are drawn into tight engagement with internal projections on the outside walls of the two frame sides in order to clamp the two sides of the frame together.

2. A securing device according to claim 1, wherein the thrust member has a longitudinal median dimension between its inner and outer ends equal to at least one half of the internal diagonal dimension of the hollow section at the mitred corner.

3. A securing device according to claim 2, wherein the clamping means comprises a recessed clamping member wherein an internally screwthreaded nut is keyed against rotation, the clamping member also being apertured into said recess for passage of and/or access to the securing screw.

4. A securing device according to any of claims 1 to 3, wherein the securing screw comprises an Allen socket grub screw.

5. A securing device according to any of claims 1 to 4, wherein the thrust member carries opposed wings for sliding engagement with internal ledges carried within the hollow section by the outside walls of the two frame sides.

6. A securing device according to claim 5, wherein the thrust member has a flat stem carrying the opposed wings at its outer end and angled corner-embracing flanges at its inner end.

7. A securing device according to any of claims 1 to 4, wherein the thrust member comprises a flat, hollow, wedge-shaped member having a corner-embracing means at its inner end.

8. A securing device according to any of claims 1 to 7, wherein the outer end of the thrust member has a seating for engagement by the end of the securing screw.

9. A hollow-sectioned metal door or window frame having its adjacent sides clamped together by a securing device according to any of claims 1 to 8.

10. A door or window frame according to claim 9, wherein the internal projections for engagement by the hooks on the clamping means are constituted by punched depressions in the outside walls of the hollow-sectioned frame sides.

11. A door or window frame according to claim 9 or claim 10, wherein the access aperture to the securing screw is formed by cooperating partial apertures in the outside walls of the frame sides at the abutting ends thereof.

12. A securing device for a hollow-sectioned metal door or window frame substantially as hereinbefore described with reference to the accompanying drawings.

13. A hollow-sectioned metal door or window frame clamped together by securing devices substantially as hereinbefore described with reference to the accompanying drawings.