GB2032497A - Building Frames - Google Patents

Abstract

A building frame, for a door or window, is made up from tubular elements, each incorporating two rolled metal strips joined by respective edge portions (6, 7). These are secured together by a rolled seam joint (8) and form flanges (2) projecting from a box section (1) formed by the main portions (3, 4) of the strips. The two strips can be identical, with the symmetrically opposed flanges performing different functions in the completed frame. The joint (8) can provide a shoulder to help retain a glazing bead (19) or a sealing strip (27). The configuration of the strips, particularly the edge portions, is such that the rolled seam is secure against being displaced under the influence of torsional forces. <IMAGE>

Description

SPECIFICATION Improvements Relating to Building Frames This invention relates to building frames such as fixed or movable frames for windows, doors or panels. For convenience, the invention will be described with particular reference to window frames.

There has been a recent departure from conventional wooden, fabricated steel and extruded aluminium window frames. This may be exemplified by British Patent No. 1353464, which shows frames constructed from rolled metal strips combined into tubular elements with interlocking flanges. There are a number of advantages in such a construction; for example tooling costs are low, expensive dies not being required, a thermal break can readily be incorporated, and a difference in internal and external finish is easily achieved by using strips of different metal or metals with different coatings.

However, one problem that still remains is the number of different sections-into which strips may have to be rolled in order to make up the complete window, including both the fixed and movable parts. It is obviously desirable to reduce the number of different sections as far as possible, and this can largely be achieved by the present invention which with a single section can make up all the necessary rigid frame elements, apart from the glazing beads, which are in any event relatively simple elements.

Another problem lies with the securing together of the strips. A convenient method, involving no other fastening elements or welding, is to have a rolled seam joint. However, with two inter-hooked flanges merely compressed together there is a tendency for them to shift relative to one under certain conditions, particularly if the tubular element is subject to torsion. While this could be cured by having a greater number of turns or rolls in the seam, that would lead to undesirable enlargement. Another factor is the width of the flange which incorporates the rolled seam. Often this has to be quite considerable to give a reasonable overlap with another frame element, or to provide a sufficient rebate for the glass for example.It is not always desirable to have the rolled seam at the free edge of the flange, where perhaps it might most conveniently be formed and where measures against mutual movement might most easily be taken, but where it could provide an unsightiy and obstructive bead. The aim of this invention is therefore also to make the rolled seam joint secure.

According to one aspect of the present invention there is provided a tubular member for a building frame such as a window, door or panel comprising two metal strips shaped and joined to form a box section with projecting flanges incorporating longitudinal joints between edge portions of the strips, each joint being a rolled seam with pressure applied transversely to the plane of the flange, and the configuration of the strips being such that mutual relative movement in the plane of the flange transverse to the longitudinal direction is impeded.

According to another aspect of the present invention there is provided a tubular member comprising two identical strips each with a first and a second edge portion and at least one intermediate longitudinal fold or bend, the strips being combined to form a box section with flanges projecting in opposite directions from one pair of diagonally opposite corners, each flange incorporating a first edge portion and a second edge portion from respective strips, and the edge portions being interfolded and compressed together to secure the box section.

For a better understanding of the invention some embodiments will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a cross-section of a frame element, and Figure 2 is a cross-section of another frame element.

The frame element of Figure 1 is made up from two identical strips which are rolled to the crosssection illustrated and combined to form a box section 1 with two flanges 2 projecting in opposite directions from diagonally opposite corners of the box. One of these flanges will act as a rebate for glazing, while the other will act as a weather lip.

Each strip is very generally of 'L' section, but there are various further folds and bends as will be described. They each have main portions 3 and 4 at right angles, and at the angle there is a small flange or rib 5 created by a double fold initially aligned with the portion 4 and projecting perpendicular to -the portion 3. It is subsequently rolled to the dotted line position to form an undercut.

Each flange 2 is formed by co-operating edge portions 6, 7 of the strips, joined by a rolled seam 8. The edge portion 6 of one strip has a number of longitudinal folds or bends dividing it into a first strip section 9 at the extreme edge, a second strip section 10 inwards from that edge and having an intermediate rib 11, and a third strip section 1 2 which is a continuation of the main portion 4. The section 10 is folded back on the box side over the section 12 so that the rib 11 is convex towards and abuts that section 12. The first edge section 9 is folded back between the other two sections.

The edge portion 7 has a first strip section 1 3 at its extreme edge which is bent back on the box side over a second strip portion which joins the main portion 3 through a curved section 1 5. This forms a longitudinal recess 16, indented into the box section, at the junction of each flange.

The respective first and second strip portions are mutually hooked by the strips being slid longitudinally, together. They are then clenched to the finished seam 8 by pressure transverse to the plane of the flange. The dimensions and configuration of the strips are such that the convex side of the fold between the sections 1 3 and 14 abuts the rib 1 1, thus preventing the width of the rolled seam increasing. The same effect could be obtained by having a rib 1 A as indicated in broken lines on the edge portion 7.

Also, the extreme edges of the sections 9 and 13 locate in the concave sides of the folds between the sections 13 and 14, and 9 and 10 respectively. Thus, the width of the seam cannot be narrowed. This makes a secure joint and the box section can be subjected to torsion without fear of misplacement.

In Figure 1, it will be appreciated that there is considerable economy in construction in using identical strips, cut to the same width and formed on the same set of rollers. However, that crosssection is not suitable for every frame element, and another one is shown in figure 2. This is generally ofT' section, and might form a fixed mullion for example.

This T-section element is formed from two strips 17 and 18, the strip 1 7 being generally flat and the strip 1 8 being generally of U-section and forming the "stem" of the T. The strip 1 7 has edge portions formed similarly to the edge portions 6 of Figure 1, and the strip 1 8 has edge portions, flanged outwardly from the arms of the U, similar to the edge portions 7 of Figure 1, these portions again being joined by a rolled seam. At the other corners of the box section there are also flanges corresponding to the flanges 5. Detailed description will therefore not be given.

Figure 1 illustrates on the right hand side how a glazing bead 19 is fitted. This is another rolled strip with a rim 20 shaped to engage under the angled flange 5, a bevel portion 21 at an angle to the portion 3 and glass G, an abutment portion 22 to press through the intermediary of a sealing strip 23 against the glass G, and a hook portion 24 which engages with its free edge behind the shoulder formed by the fold between the strip sections 9 and 10. A further sealing strip 25 is sandwiched between the glass and the flange 2 and the concave side of the rib 11 provides a detent for this strip. The bead is fitted by engaging the hook portion and snapping the rim 20 past the flange 5. Double glazing can be accommodated using a bead 19 with a small bevel portion.

Figure 2 illustrates a use for the recess 1 6. In conjunction with the above mentioned shoulder between the sections 9 and 10, it forms a snap-in seat for the bead 26 of a sealing strip 27, which has a flange 28 overlying the remaining portion of the flange 2. A movable frame shutting into this rebate seals against this strip. It will be understood that a similar strip can be provided in one of the recesses 1 6 of Figure 1.

Although the strips 17, 18 of Figure 2 are differently shaped, and initially of different widths, it can be arranged that the sum of their widths is the same as the sum of the strip widths that make up the Figure 1 element. Thus the same initial strip material can be used without waste for both types, being slit in different proportions. An integral multiple of the glazing bead can also correspond to the basic strip width, again enabling slitting without waste.

Claims (15)

Claims

1. A tubular member for a building frame such as a window, door or panel comprising two metal strips shaped and joined to form a box section with projecting flanges incorporating longitudinal joints between edge portions of the strips, each joint being a rolled seam with pressure applied transversely to the plane of the flange, and the configuration of the strips being such that mutual relative movement in the plane of the flange transverse to the longitudinal direction is impeded.

2. A tubular member as claimed in claim 1, wherein the rolled seam is at an intermediate zone of the flange and the convex edge of a fold of one edge portion abuts a longitudinal rib formed in the other edge portion, thereby to prevent the seam width increasing.

3. A tubular member as claimed in claim 1 or 2, wherein the free edges of said edge portions face in opposite directions and at least one said edge is confined by the interior of a fold of the opposite edge portion, thereby to prevent the seam width decreasing.

4. A tubular member as claimed in claim 1, 2 or 3, wherein one edge section has, in order inwards from the edge, first, second, and third strip sections with the second section being folded back over the third section and the first section being folded back between the second and third sections, and the other edge portion of each joint has, in order inwards from the edge, first and second strip portions, the first section being folded back over the second section, both first strip sections being mutually hooked, and all the sections along the first section zone being compressed together to secure the joint.

5. A tubular member as claimed in claims 2 and 4, wherein said longitudinal rib is formed on said second section of said one edge portion and is convex towards the third section, and wherein the fold between the first and second sections of the other edge portion abuts said rib.

6. A tubular member as claimed in any preceding claim, wherein each flange projects generally at right angles to an adjacent face of the box section, and wherein the rolled seam provides a shoulder spaced from said face.

7. A tubular member as claimed in claim 6, wherein said face is indented at the junction of the flange, and on the same side of said flange as said shoulder.

8. A tubular member as claimed in any preceding claim, wherein each strip is similarly shaped with first and second edge portions, each first edge portion being joined to the second edge portion of the opposite strip and the flanges projecting in opposite directions from diagonally opposite corners of the box section.

9. A tubular member as claimed in any one of claims 1 to 7, wherein one strip is generally flat with similar first edge portions and the other strip is generally channel shaped with similar second edge portions, the flanges projecting in opposite directions from adjacent corners of the box section.

10. A tubular member comprising two identical strips each with a first and a second edge portion and at least one intermediate longitudinal fold or bend, the strips being combined to form a box section with flanges projecting in opposite directions from one pair of diagonally opposite corners, each flange incorporating a first edge portion and a second edge portion from respective strips, and the edge portions being interfolded and compressed together to secure the box section.

11. A tubular member as claimed in any preceding claim, wherein the box section is formed with further flanges each projecting from the same face of the box section as an associated first flange but being inclined thereto to create an undercut formation.

12. A tubular member as claimed in claim 11, wherein each further flange is a doubled back intermediate strip portion at a corner of the box section.

13. A frame composed of tubular members as claimed in any preceding claim.

14. A frame as claimed in claim 13, wherein the sum width of the strips of each tubular member is the same.

15. A frame as claimed in claim 13 or claim 14, with at least one tubular member as claimed in claim 8, and at least one tubular member as claimed in claim 9, wherein the sum width of the two strips of the member as claimed in claim 8 is the same as the sum width of the strips of the member as claimed in claim 9.

1 6. A tubular member substantially as hereinbefore described with reference to Figure 1 or Figure 2 of the accompanying drawing.