GB2104139A - Spacer frame for multiple- glazed units - Google Patents

Abstract

A spacer frame, for use in multiple-glazing units, is assembled by taking a piece of tubing having a strengthened portion in its cross- section, inserting desiccant and plugging the ends, cutting notches at appropriate intervals, blocking the notches, and then bending the strengthened portions at the notched points to form a closed framework and joining the plugged ends by means of a connector 4. <IMAGE>

Description

SPECIFICATION Improvements in or relating to spacer frames for use in multiple-glazed units This invention relates to spacer frames for use in spacing two sheets of glazing material in multiple-glazed units e.g. window or door panels.

Spacers for separating the glass panels of multiple-glazed units are generally formed from a strip of metal which is roll-formed into a tube. The tubular spacer extends around the multiple-glazed unit between the outer margins of the glass panels, sealant materials being used between the glass and the sides of the spacer frame and to fill gaps between the outside of the frame and edges of the glass.

In order to prevent any condensation of moisture between the glass panels, which would interfere with visibility, the spacer tube bore contains a desiccant which absorbs any such moisture.

In order for the desiccant to be effective, air passages must be provided between the bore of the spacer-tube and the space between the glass panels. However, any such air passages must be small enough to prevent the desiccant from falling from the spacer into the space between the glass panels.

Certain types of spacer tube are manufactured from metal strip and have a seam that is created when the two strip edges are bent inwardly to butt together. The seam may be welded or nonwelded. This is known as "butt-seam" tube.

Spacer-tube that is manufactured by extrusion or by 'drawing' has no seam and has to be pierced or perforated before being used in multiple-glazed units. Spacer tube that has an over-lap seam or double-over-lap seam is also commonly used.

One disadvantage of the butt-seam tube is that the seam can easily be caused to open, thus allowing possible escape of desiccant. This type of tube has a tendency to open at the seam, at the tube ends, when the tube is laterally cut to length, and especially when corner-pieces are inserted into the tube ends.

It is general practice during the construction of a multiple-glazed unit to cut the spacer-tube to suitable lengths, then assemble four tubes each connected one to the other at their ends by means of corner-pieces, to form a rectangular frame. The frame is the means of separating the panes of glass, which on assembly comprise the finished unit The four tubes which normally comprise the spacer frame are generally adjoined to one another by corner-pieces. The corner-piece has two legs fixed so that insertion into the tubes causes the tubes to be set at a right-angle to one another. One corner-piece is used at each corner of the frame.

It is essential that the spacer frame is accurately made and that it remains rigid during the assembly process. Should one or more corner-pieces be loose fitting during the subsequent assembly processes this leads to problems on the assembly line. Further, if the spacer frame becomes "floppy" i.e. non-rigid, then it will not stand up to the stresses involved in the assembly process wherein the frame is sandwiched between pieces of glass, normally in a vertical plane, and is then sealed into the unit. It is an object of this invention to construct a rigid spacer frame without the use of corner-pieces.

According to this invention we provide a method of assembling a spacer frame for use in multiple-glazed units, comprising: (a) taking a length of metal tube of substantially closed cross-section, one portion of this cross-section being of strengthened construction, (b) plugging one end of the tube, inserting desiccant material and then plugging the other end, (c) cutting a series of slots or notches in the cross section of the tube at appropriate intervals while leaving the strengthened portion substantially intact, (d) blocking the openings in the tube formed by cutting the notches, (e) bending the strengthened portion of the cross section, at the notched points, to form a closed framework, and (f) joining the ends of the tubes by means of a connecting piece.

Preferably the tube is of substantially rectangular cross-section.

Preferably the strengthened portion is formed by overlapping edge portions of a metal strip when forming the tube, the overlapping portions being secured together e.g. by crimping or welding.

Preferably the tube is roll-formed from steel strip, although other metal e.g. aluminium may be used.

Preferably the tube is formed by forming metal strip into a tube, with overlapping edges of the strip forming a strengthened portion of double thickness, the overlapping edges being secured by crimping, brazing, soldering or welding.

Preferably the connecting piece is of rigid plastics or metal material.

Preferably the closed framework is of square or rectangular configuration.

The invention will now be further illustrated by reference to the accompanying drawings in which Figure 1 shows a cross-section through a tube suitable for use in assembling a spacer frame by the method according to the invention.

Figure 2 shows the tube ends plugged and desiccant and connecting piece inserted.

Figures 3A-3C, show three methods of cutting or notching the tube in the method according to the invention.

With reference to Figure 1, a tube suitable for forming a spacer frame has a substantially rectangular cross-section as shown in this figure.

This is roll-formed from a strip of metal with overlapping edge portions 1 and 2 being secured together e.g. by spot welding or crimping to give a strengthened portion.

As shown in Figure 2 the ends of the tube are plugged with plugs 3, after inserting desiccant material into the tube, and a connector 4 is inserted into one end and this end of the tube is crimped.

As shown diagrammatically in Figure 3 the tube may be cut, to form slots or notches, in 3 alternative ways, as exemplified in 3A, 3B or 3C, at appropriate intervals along the length of the tube. In every case the strengthened portion 5 of the tube remains uncut. In Figure 3A a parallel sided slot is formed, in Figure 3B the notch is a right-angled section and in Figure 3C a parallel sided notch is formed by removing a piece of metal.

When the cutting has been done the openings in the tube so formed are blocked to prevent desiccant from spilling out. The tube is then formed by bending the strengthened portion 5 at the notched points to produce a closed framework e.g. of 1 metre0.5 metre dimensions.

Finally the plugged ends are joined by means of connecting piece 4 and firmly pushed together to form a butted joint.

Claims (9)

Claims

1. A method of assembling a spacer frame for multiple-glazed units comprising: (a) taking a length of metal tube of substantially closed cross-section, one portion of this cross-section being of strengthened construction, (b) plugging one end of the tube, inserting desiccant material and plugging the other end, (c) cutting a series of slots or notches in the tube cross-section at appropriate intervals, while leaving the strengthened portion substantially intact, (d) blocking the tube openings formed by cutting the slots or notches, (e) bending the strengthened portion of the tube cross-section at the notched points to form a closed framework, and (f) joining the ends of the tube by means of a connecting-piece, to complete the closed framework.

2. A method as claimed in claim 1 in which the tube is of substantially rectangular cross-section.

3. A method as claimed in claims 1 or 2 in which the tube is formed from metal strip by overlapping edge portions of the strip and securing the overlapping edge portions, to form a strengthened portion of double thickness.

4. A method as claimed in claim 3 in which the edge portions are secured by crimping or welding.

5. A method as claimed in claims 1 to 4 wherein the tube is of steel.

6. A method as claimed in claims 1 to 5 wherein the closed framework is of rectangular configuration.

7. A method as claimed in claim 1 wherein the connecting piece is of rigid plastics or metal material.

8. A spacer frame constructed and assembled according to the method claimed in any one of claims 1 to 7.

9. A multiple-glazed unit containing a spacer frame as claimed in claim 8.

1 0. A method of assembling a spacer frame for a multiple-glazed unit, substantially as hereinbefore described.