DESCRIPTION

This invention relates to a grid structure of mutually perpendicular glazing bars and to a glazing bar in or for such a grid structure. The invention has particular application to glazing bars intended to simulate a traditional timber Georgian-type window effect. An object of the invention is to provide a glazing bar arrangement which allows individual panes of glass, either single *or multiple glazed, of a composite window construction to be inserted thereby achieving a true Georgian effect, and to be removed for repair or replacement. Heretofore it has been necessary to remove all the glazed sections in order to replace one section, whereas the present invention allows individual panes of a composite Georgian-type window to be repaired or replaced as required.

US-A-4845911 shows a grid structure for supporting and separating a plurality of individual, relatively small panes of glass. Individual panes can be removed and replaced, but the structure can be disassembled from the outside since all the parts are clipped together and can be undipped easily. That poses problems of security.

According to one aspect of this invention there is provided a grid structure of mutually perpendicular glazing bars comprising at least one glazing bar extending between and substantially perpendicular to an aligned pair of glazing bars which abut it, and

locating means embedded in the adjacent ends of the bars of the aligned pair and extending therebetween through said one glazing bar whereby to locate the aligned pair of glazing bars substantially relative to one another and to said one glazing bar, each glazing bar having a typical cross-section comprising a central load bearing portion, a base portion which projects from either side of the central portion to provide a seat for a pane of glazing material, and a snap-fit formation at a location on the central portion which is spaced from the base portion, and in combination with each glazing bar, a clamping section adapted to be releasably snap-fitted onto the snap-fit formation whereby to clamp a respective pane of glazing material on each of said seats.

Preferred features of the grid structure are claimed in sub-claims 2 to 5.

A Georgian type window incoprorating a grid structure in which this invention is embodied will have substantial strength such as to withstand considerable wind loads and other loads to which it may be subjected when installed. Also the preferred embodiment of this invention has a high standard of security being most difficult to disassemble from outside even should the clamping section be removed. That is because, even though the clamping sections can be stripped off and they are on the outside, the rest of the grid structure cannot be disassembled because the locating means are inaccessible being embedded in the glazing bars. Also the individual panes are difficult to extract from the grid structure without being broken, when working from outside, because they fit snugly with edges in

abutment with the glazing bars. Moreover the security tape by which the panes of glass are bonded in situ is inaccesible from outside.

According to another aspect of this invention in or for a grid structure according to said one aspect of this invention there is provided a glazing bar comprising a central load bearing portion, a base portion which projects from either side of the central portion to provide a seat for a panel of glazing material, and a snap-fit formation at a location on the central portion which is spaced from the base portion and operable to receive a snap-fit clamping section which is to be snap-fitted thereon whereby to clamp a respective pane of glazing material on each of said seats, wherein the central load bearing portion and the base portion cure interlocked.

Preferred features of that glazing bar are claimed in sub-claims 7 to 12.

Although the glazing bar is essentially for Georgian style windows in which a plurality of small separate panes form a composite window surface, nevertheless it is applicable to windows where a single glazing bar divides the glazing surface into two separate panes only.

One form of a Georgian window in which this invention is embodied, and a modification thereof, is described now by way of example with reference to the accompanying drawings of which:-

Figure 1 is a front elevation of the Georgian window;

Figure 2 is a section on the line II-II in Figure 1 with the releasable snap-fit cap shown displaced in dotted outline; and

Figure 3 shows a modified form of glazing bar for use in the window shown in Figures 1 and 2.

Figure 1 shows a window of the Georgian style. It comprises an outer rectangular frame 10 and peripheral beading 11 both formed of uPVC extrusions. The frame 10 and beading 11 are similar to that used in conventional uPVC windows:

The rectangular aperture formed by the frame 10 is divided into smaller rectangular apertures for individual panes 12 of glass by vertical glazing bars 13, which extend from the top to the bottom of the frame 10, and by horizontal rows of aligned shorter glazing bars 14A-14C. Each vertical glazing bar 13 extends between and is perpendicular to an aligned pair 14A and 14B, 14B and 14C of the shorter glazing bars which abut it. Each glazing bar 13,14A,14B,14C carries its own beading cap 15 which is effectively an integrated pair of strips of the conventional beading 11 arranged symmetrically and adapted to be snap- fitted onto the remainder of the respective glazing bars as shown in Figure 2. Mitered joints are formed at the junction of the peripheral beading 11 with an end of a respective one of both the vertical glazing bars 13 and the outer horizontal glazing bars 14A and 14C, in much the same way as they are formed between the strips of peripheral beading 11 at each corner of the frame 10.

Suitable fixing means are provided at each junction between the frame 10 and an end of a glazing bar 13,14A,14C. For instance, the fixing means may comprise screws engaged in the hollow of the metal extrusion 16 of the respective glazing bar.

Each pane 12 of glass to be fitted into one of the smaller rectangular apertures may be either a single pane of glass or a multiple glazed unit.

Figure 2 shows the cross-section of a vertical glazing bar 13. That is similar to the cross-section of each of the shorter horizontal glazing bars 14A, 14B and 14C. It shows that each glazing bar comprises a T section which is formed by two interlocked extrusions 16 and 17 and the cap formed by the double beading 15. The stem of the T comprises the extrusion 16 which is formed of metal. That has a domed arrow-head 18 at its outer end on which the double beading 15 is snap-fitted. It is hollow having an elongate rectangular slot 19 formed centrally in it, the slot extending along the length of the stem. The end 21 of the metal extrusion 16 remote from the domed arrow-head 18 is flanged on both sides so that its width is greater than that of the remainder of the metal extrusion 16. Also the flanged end 21 is spaced from the major hollow portion of the metal extrusion 16 by an opposed pair of recesses 22 which form a waist portion 23.

The plastics extrusion 17 forms a base portion of the glazing bar, that base portion projecting from either side of the central portion of the glazing bar to form the arms 24 and 25 of the T. A central aperture 26 is formed in the extrusion 17 and is sized to

snugly receive the flanged end portion 21 of the metal extrusion 16. The latter projects upwardly from that central aperture 26 through an opening which is formed by flange portions 27 and 28 of the plastics extrusion 17 which each project into a respective one of the recesses 22 in which they are a snug fit. Hence the two extrusions 16 and 17 are interlocked. The plastics extrusion 16 includes a pair of upstanding thin portions 29 and 31 which line the respective side of the hollow central portion of the metal extrusion 16, extending over a major part of the stem of the T.

Figure 2 shows that the upper part, including the domed arrow-head 18 of each of the aligned pair of shorter glazing bars 14A and 14B for example is cut away to provide clearance for the double beading cap 15 snap-fitted onto the domed arrow-head portion 18 of that intervening vertical glazing bar 13. Mitred joints are formed between juxtaposed portions of the arms 24 and 25. The lower corners of the metal extrusions 16 of the aligned pair of shorter glazing bars 14A and 14B axe also cut away to receive the flanged end 21 of the metal extrusion 16, of the intervening glazing bar 13, there being a slot formed in the respective arm 24,25 to receive the metal extrusion 16 of the respective shorter glazing bar 14A,14B. The remainder of the ends of those metal extrusions 16 of the aligned pair of short glazing bars 14A and 14B, 14B and 14C abut the respective upstanding thin portion 29,31 of the plastics extrusion 17. A metal plate 32 is fitted into the slot 19 at either end of the aligned pair of shorter glazing bars 14A and 14B, 14B and 14C, and extends through a lateral aperture formed through the stem

portion of the T-shaped vertical glazing bar 13, the plate 32 being fixed at either end to the respective shorter glazing bar 14A,14B,14C by rivets 33. Other suitable fixing means, such as countersunk setscrews or self-tapping screws could be used instead of the rivets 33.

It will be realised that the grid structure formed by the vertical and horizontal glazing bars 13,14A,14B and 14C, fitted into the central aperture of the frame 10, and the plates 32 by which each aligned pair of shorter glazing bars 14A and 14B are joined together and located relative to the intervening vertical glazing bar 13 cOmprise an interlocked structure. Loads applied to that structure will be uniformly distributed throughout that structure. The grid structure is designed to be self-supporting and self-sustaining even without any panes 12 of glass being fitted into its apertures so it can be transported to a site at which it is to be installed, the panes 12 of glass being fitted after it has been installed.

The double beading caps 15 are separated from the respective arrowhead portions 18 of the respective glazing bars (as shown dotted in Figure 2) to free each aperture for insertion of a pane 12 of glass.

The seat portion 34 afforded by each arm of the T that is formed by the plastics extrusion 17 at the corner formed between that arm and the stem and which extends over the outer part of the flanged end 21 of the metal extrusion, is lined with a strip of security tape 40. That is a strip of material with a layer of self-adhesive on each of its opposed faces. Hence that strip adheres to the respective portion of

the plastics extrusion 17 which forms the seat 34 and provides an adhesive layer on which the pane 12 of glass is laid. Hence the pane 12 of glass is bonded to its seat 34. Also the pane 12 of glass closely abuts the edge of the stem of the T-section of the respective glazing bar along the respective edge of the pane 12 of glass. The respective upstanding stem portion 29,31 of the plastics extrusion 17 lies between the glass and the metal extrusion 16 so as to avoid direct glass and metal contact. Once the pane 12 of glass has been laid upon and bonded to the respective seat 34, the double beading cap 15 is fitted to clamp it in position, a respective gasket 41 carried by the cap 15 being urged by the resilience of its material against the pane 12. The resilient compressibility of the gasket material allows the cap 15 to be snap-fitted onto the arrowhead 18 and ensures that that material makes sealing contact with the glass when it has been so fitted.

It will be understood that the panes 12 of glass augment the structural integrity of the total window structure by filling the apertures and abutting the portions of glazing bars that form the periphery of those apertures. Furthermore it is extremely difficult to extract each pane 12 of glass from the side of the window on which the double beading caps 15 run, even when those caps have been released from the respective domed arrowheads 18, because of the double adhesive security strip. On the other hand it is a simple process to replace a pane of glass by first removing the respective double beading caps 15 and then cutting the security strips with a knife, working from inside the window.

Figure 3 shows an alternative form of glazing bar which employs metal extrusions for the double beading cap 15A and the base portion 35 which forms the arms of the T. There are intermediate extrusions 36 and 37 of plastics material. One 37 is provided between the central metal extrusion 16 and the other metal extrusion 35 which forms the arm of the T, this extrusion 37 including the upstanding thin portions which line the sides of the stem portion of the T.

In either embodiment described above, a compressible gasket could be used instead of the security tape although the resultant window would be less secure than it would have been had Security tape been used.