GB2172911A

GB2172911A - Curtain walling

Info

Publication number: GB2172911A
Application number: GB08508400A
Authority: GB
Inventors: James Alan Macey
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-03-30
Filing date: 1985-03-30
Publication date: 1986-10-01
Also published as: GB2172911B; GB8508400D0

Abstract

A curtain walling structure in which curtain panels are supported by a framework of upright mullions (11, Figure 1) and horizontal transoms (13 Figure 1,) 14 which carry inner sealing elements 15 and spaced mounting members 30a, 30b which in turn carry outer sealing elements 16 and support pressure plates 19. Additionally, the mounting members may carry intermediate elements (40a, 40b) of thermally insulating material to form an additional thermal break. <IMAGE>

Description

SPECIFICATION Curtain walling This invention relates to curtain wall structures of the kind comprising a framework formed from upright frame members, usually known as "mullions", and horizontal frame members, usually known as "transoms", and a plurality of infill or curtain panels (which may be glazing panels) located in sealing gaskets carried by the framework.

The invention is concerned with various aspects of such curtain wall structures related particularly to the mounting of the curtain panels on the framework. Amongst the objectives of the invention is the reduction of heat transfer across the structure for example by the provision of a thermal break between components exterior to the curtain panels and those on the interior of the wall structure.

Throughout the specification the terms "interior" and "exterior" will be used to refer to the faces of the wall structure which are presented towards the inside and outside respectively of the buiiding of which the structure forms part.

The invention resides in a curtain wall structure in which frame members carry sealing gasket assemblies along their exterior faces to receive marginal portions of curtain panels which close apertures in the framework bounded by the frame members, wherein each gasket assembly comprises an inner sealing element on the exterior face of the frame member and an outer sealing element spaced from the inner sealing element towards the exterior of the structure, the outer sealing element being supported from the frame member in spaced relation thereto by retaining means carried by the frame member.

The retaining means preferably comprises a plurality of support members which are spaced at intervals along the length of the frame member so that the intermediate element engages and extends between such support members. The support members may be formed as extrusions of aluminium, or mouldings of any suitable metal or of any suitable plastics material.

Where the support members are carried by transoms, that they may also serve to take the weight of the curtain panel above them and transmit such weight to the transom. For this purpose, some or all of the support members carried by transoms may be of greater length (i.e. in the direction of the length of the transom) than those carried by mullions.

The support members may be formed as lengths cut from a suitable extrusion. Conveniently, the support members include a base portion which is adapted to be assembled with the frame member, and a spacer portion whereby the outer sealing element is supported. The spacer portion may be adapted to be severed at one or more alternative positions whereby its overall width can be reduced to suit differing thickness of curtain panels.

The gasket assembly preferably also includes an intermediate element of thermally insulating material supported by the retaining means.

According to a further aspect of the invention we provide a curtain wall structure in which the frame members carry sealing gasket assemblies along their exterior faces to receive marginal portions of curtain panels which close apertures in the framework bounded by the frame members, wherein each gasket assembly comprises an inner sealing element on the exterior face of the frame member, an outer sealing element spaced from the inner sealing element towards the exterior of the structure and an intermediate element of thermally insulating material which supports the outer sealing element and is itself supported from the frame member by retaining means carried by the frame member.

The intermediate element may extend without interruption from the inner sealing element to the outer sealing element, and may be integrally united with one or both of such sealing elements.

Alternatively, the intermediate element may be separated from the inner sealing element. In the latter case it may extend towards the interior from the outer sealing elemerit for only part of the distance between said sealing elements. In this case, the intermediate element may be integrally united with the outer sealing eiement, or it may be separate therefrom. Desirably, the intermediate elements includes a part which extends over the ends of the support members remote from the frame member.

In order to support curtain panels on opposite sides of frame members other than those at the edges of the structure, the gasket assemblies carried by frame members which form a common boundary between two adjacent aperatures in the framework preferably include a pair of inner sealing elements disposed at opposed edges of the exterior face of the frame member, and a pair of outer sealing elements correspondingly arranged.

The pair of outer sealing elements may be integrally united with one another, and the pair of inner sealing elements could be integrally united with each other through the intermediate element.

Nevertheless it is preferred for the sealing elements to be formed separately from the intermediate element so that the latter can be made of less flexible material.

Pressure plates bearing on the outer sealing elements may also be carried by the retaining means.

The invention will now be described by way of example with reference to a preferred embodiment of curtain wall structure in accordance with the invention as illustrated in the accompanying drawings wherein: Figure 1 is a diagrammatic view of a portion of the framework of a curtain wall structure in accordance with the invention; and Figure 2 is a fragmentary perspective view, on an enlarged scale, of a region of the curtain wall structure at the junction between a mullion and two adjacent transoms, showing certain components in "exploded" relation.

With reference to Figure 1, the curtain wall structure comprises a plurality of vertical mullions of which three, 10, 11 and 12 are shown, the mullions being interconnected by a plurality of transoms, two of which are indicated by references 13 and 14. The framework of mullions and transoms defines a plurality of rectangular frames each of which is intended to be occupied by a curtain panel which may comprise a sheet of glass or other glazing material, which can be transparent, translucent or opaque, or some other building panel or other solid infill. Figure 1 also shows diagrammatically the arrangement of support members 30a, 30b as hereinafter explained.

Figure 2 shows a portion of the curtain wall structure at the junction between mullion 11 and transoms 13 and 14, omitting the curtain panels for clarity.

The mullions are formed as lengths of extruded aluminium having a generally rectangular box-like section 20 comprising two parallel longer side walls 21 joined by two parallel shorter side walls 22. The longer side walls each have an extension portion to provide a pair of opposed flanges 23.

The free ends of the flanges 23 are formed with respective lateral ribs 25 which extend in spaced reiation to the adjacent side wall 22 of the box-like section to provide an engagement means inciuding grooves or rebates 26, the purpose of which is described below. A longitudinally extending rebate 24 of undercut form is also formed in the exteriorly directed face of each rib 25. The several flanges and rebates referred to above are conveniently formed in a single aluminium extrusion which is cut to length as required.

The transoms are conveniently also formed from lengths of the same extrusion, although if necessary, a different extrusion could be employed.

The mullions and transoms are assembled together in the framework by means which do not form part of the present invention and accordingly will not be described.

Each of the rebates 24 of the mullions and of the transoms carries an elastomeric inner sealing element 15 which consists of an extruded strip formed on the exterior face thereof with several substantially parallel, outwardly extending, inclined, flexible tongues to make sealing contact with the resp,ective curtain panel, and formed with an inwardly extending bead 15a having a crosssection such that it can be forced into the respective rebate 24, thereby to hold the element in position on the mullion or transom as required.

In addition to the inner sealing elements 15, the gasket assembly in which each curtain panel is located includes corresponding outer sealing elements 16 which conveniently are integrally united in pairs as a sealing strip 17. Additionally, square or cruciform exterior gasket components 18 are provided to cover the junction regions between mullions and transoms, although alternatively the strips 17 could be mitred at the junction.

The outer sealing elements 16 are conveniently of a form similar to that of the inner sealing elements, having flexible fingers in this case directed inwardly to come into sealing contact with the exterior surface of the curtain panels, and longitudi nally extending beads 16a on the same face as the tongues to engage in rebates afforded by intermediate elements, as hereinafter described, carried by the transoms and mullions. The gasket components 18 may similarly interfit with end parts of such intermediate elements in the region of the junction between mullions and transoms.

Exterior to the outer sealing elements 16, pressure plates 19 are provided to hold the outer sealing elements firmly in position against the curtain panels. The pressure plates 19 are normally provided with means to engage elongate covers or caps 19a which serve to give a finished appearance to the assembly and also protect the screws or other fixing devices which serve to hold the pressure plates in place as hereinafter described.

As seen clearly in Figure 2, the mullions and transoms carry retaining means comprising a plurality of support members which are most conveniently formed from aluminium extrusions cut to appropriate lengths, although they could be formed as mouldings of metal or of plastics material. The illustrated structure utilises two principle types of support member which differ only in their length. The mullions carry support members 30a of shorter length, their principle function being to provide a means of securing the pressure plates in place. The horizontally extending transoms carry at least some support members 30b which are of greater length since they serve also the additional purpose of providing support for the lower edges of the curtain panels, although some of the support members carried by the transoms may be of the shorter type.As illustrated in Figure 1, the longer support members 30b may conveniently be arranged adjacent to the ends of the transoms, whilst at intermediate positions the transoms carry the shorter support members 30a. Also as illustrated in Figure 1 the support members 30a may be arranged to face alternately in opposite directions.

As illustrated in Figure 2, the support members 30a and 30b both comprise an aluminium block, conveniently cut from a length of aluminium extrusion which affords firstly a base portion 31 and secondly a transverse body portion 32. The shape and dimensions of the base portion 31 are such as to enable this portion to engage in the respective rebates 26 in the transoms and mullions as a close fit. In practice, the lengths of such extrusion which form the support members 30a and 30b are assembled with the frame members by sliding them end-wise onto the frame member as the latter are assembled together to form the framework. Alternatively, they may be assembled with the transoms and mullions in the factory and retained in place temporarily during transport by any suitable means.

Normally, once the curtain wall structure has been assembled, the support members will remain in their initial positions without any special provision for securing them in place. However, if necessary, particularly on the mullions, spacer members may be provided between adjacent support members, or alternatively the support members may be secured in place by means of suitable fastening elements. In this case, the base portions of the support members may be formed with apertures for the reception of appropriate fastening elements, which may conveniently be of the selfpiercing and tapping kind so as to penetrate the adjacent wall 22 of the mullion or transom.Further, the support members may be designed for assembly with the exterior face of the mullions or transoms from the front for example by joggling the support member so that one edge of the base portion enters one rebate first, then the other edges enters the other rebate. In this case the support member may be secured against removal by packing pieces or by means of screws.

The body portion 32 of the extrusion from which the support members are formed comprises a web 33 formed with several transversely extending flanges 34 which extend to one side thereof in spaced relation and terminate in lips 35 directed towards the base portion 31. The other face of the web 33 is formed with longitudinally extending grooves 36 at positions which register with the gaps between the flanges 34 and lips 35. These grooves serve as guides whereby the extrusion can be cut or ground down to a variety of different widths, as well as serving to locate an intermediate element of the gasket assembly as hereinafter described.

In use, the body portion 32 of each support member 30a or 30b acts as a spacer for the outer sealing elements 16, as well as a support for the pressure plates 19 and in the case of the members 30b a support for the curtain panels. Variation of the width of the body portion 32 enables the same extrusion to be used with curtain panels of various thicknesses.

The support members 30a, 30b serve to locate the intermediate elements of the gasket assemblies as previously mentioned. In the illustrated embodiment there are two types of intermediate element 40a and 40b which are associated respectively with the support members carried by the mullions and by the transoms. The mullion intermediate elements 40a comprise a transverse web 41 with lateral flanges 42 having inwardly turned lips at their free ends. The widths of the web 41 and of the flanges 42 are such that the element 40a fits over the free, outer end of the body portion 32 of any support member with the lips engaging in the nearest groove 36 on the one side of the web 33 and under the nearest lip 35 on the other side of the web 33, irrespective of the width of the body portion 32, and irrespective of the length thereof.

On the face of the web 41 opposite to the flanges 42, four parallel flanges 43 are arranged in pairs with inwardly directed lips so as to define two, parallel, under-cut rebates 44 for the reception of the beads 16a on the outer sealing elements 16 whereby those elements may be assembled on to the intermediate elements 40a. Whilst in the illustrated arrangement the outer sealing elements 16 are integrally united into a single sealing strip 17, it will be appreciated that a pair of separate sealing elements could alternatively be employed for this purpose.

The intermediate elements 40b associated with the transoms are similar to those associated with the mullions, but in the illustrated embodiment they are also adapted to serve as drip cills. For this purpose, one of the flanges at the interior side of the web is extended so that an out-turned margin thereof engages the adjacent transom, preferably beneath the inner sealing element 15. As shown in Figure 2, the transom intermediate element 40b comprises a web 41, a single flange 42, flanges 43 and rebates 44, all as provided on the mullion intermediate element 40a, the second flange 42 of the latter being replaced by a wider flange 42a terminating in an out-turned margin 45.In use, the wider flange 42a is disposed on the uppermost side of the body portions of the support members 30a, 30b carried by the transoms with the free margin 45 received between the inner sealing element 15 and the exteriorly presented face of the rib 25 of the transom. The element 40b thus serves as a tray to collect water of condensation, and also any water than may pass the sealing gaskets. To enable such water to be delivered to the exterior of the building, drains slots 17a, 19b, 19c are formed in the sealing strip 17, pressure plates 19 and cover plates 19a respectively. The drainage slots also serve an additional function as pressureequalisation means which assists the assembly of the curtain panels with the gaskets.

In order the retain the curtain panels securely, the pressure plates 19 are secured by means of fastening elements, conveniently in the form of self-piercing and tapping screws, which extend through slots formed in the pressure plates for this purpose and into the body portions of the support members 40a, 40b and in particular through one or more of the flanges 34 thereof.

As can be seen, the exterior metallic components of the curtain wall structure, namely the pressure plates 19, are spaced from the metallic mullions and transoms by a substantial distance. The gap between such interior and exterior components is substantially void so as to provide good thermal insulation. The support members 30a, 30b which are disposed in this gap occupy only a relative small part of the space so that bridging of the gap by thermally conducting members is reduced to a minimum even where the support members are metallic.However, the exterior ends of the support members are capped by the intermediate elements 40a, 40b of the gasket arrangement, which can conveniently be made of extrusions of PVC or other suitable, thermally insulating material, so as to afford, in addition to the sealing strips 17, a thermal break between the pressure plates 19 and the mullions and transoms.

Accordingly, the only thermally conductive path from the exterior to the interior is through the fastening elements whereby the pressure plates are secured to the support members, and this may be minimised by the use of a collar of insulating material around the shank of the fastener and between the pressure plate and the head of the fastener.

Whilst the use of thermally insulating intermediate elements provide a particularly effective thermal break between the exterior and interior metallic components of the curtain wall structure, in some cases it may be possible to omit such intermediate elements and rely wholly on the thermal insulation provided by the outer sealing strips 17, particularly if the latter are increased in thickness as compared with the arrangement illustrated.

Whilst in the illustrated embodiment the gasket assembly includes three separate components, namely inner sealing elements, intermediate elements and outer sealing elements, it will be appreciated that it may be possible for two or more such elements to be integrally united. Thus, the flange 42a could be integrally united with the adjacent sealing element 15 and/or one or both of the sealing elements 16 could be integrally united with the intermediate element. Further, the lower flange 42 of the intermediate element 40b could be extended in a manner similar to the flange 42a and integrally united with the adjacent inner sealing element 15.

Also, whilst the intermediate elements associated with the mullions may be different from those associated with the transoms, it will be appreciated that it would be possible to use the same component in each case.

Whilst the invention has been described above particularly in relation to transoms and mullions which form a common boundary between adjacent apertures in the framework, it will be understood that similar arrangements may be adopted at the edges of a curtain wall structure. At the upper and lower edges, it may be necessary only to provide a single inner sealing element 15 and a single corresponding outer sealing element 16. At the vertical edges a similar situation may arise, or alternatively the curtain walling may be extended around an internal or external corner. For this purpose, an end mullion may be set at an angle which bi-sects the corner and may carry a series of outwardly directed special support members specifically adapted for use at such positions.Thus, at an external corner a specially adapted support member may include a pair of divergent body portions carried by a single base portion, each body portion being similar in construction to the body portion of the illustrated support members, and the divergent body portions carrying respective intermediate members at the outer ends thereof. A corner piece may be used to fill the angle between the two body portions and a sealing strip 17 with its associated pressure plate 19 may be assembled with each intermediate element so that one of the sealing elements 16 engages the adjacent curtain panel, whilst the other sealing element 16 engages the corner piece. At such a corner arrangement, the inner sealing elements 15 may be carried by an appropriately designed adaptor member which is associated with the rebates 24 to hold the inner sealing elements 15 at the appropriate angle relative to the corner mullion.

Claims

1. A curtain wall structure in which frame members carry sealing gasket assemblies along their exterior faces to receive marginal portions of curtain panels which close apertures in the framework bounded by the frame members, wherein each gasket assembly comprises an inner sealing element on the exterior face of the frame member and an outer sealing element spaced from the inner sealing element towards the exterior of the structure, the outer sealing element being supported from the frame member in spaced relation thereto by retaining means carried by the frame member.

2. A structure according to Claim 1 wherein the retaining means comprises a plurality of support members which are spaced at intervals along the length of the frame member.

3. A structure according Claim 2 wherein the support members carried by transoms serve to take the weight of a curtain panel and transmit such weight to the transom.

4. A structure according to Claim 3 wherein some or all of the support members carried by transoms are of greater length than those carried by mullions.

5. A structure according to Claims 2 to 4 wherein the support members are formed as lengths cut from an extrusion.

6. A structure according to Claims 2 to 5 wherein the support members include a base portion which is adapted to be assembled with the frame member, and a spacer portion whereby the outer sealing element is supported.

7. A structure according to Claim 6 wherein the spacer portion is adapted to be severed at one or more alternative positions whereby its overall width can be reduced to suit differing thickness of curtain panels.

8. A structure according to any one of the preceding claims wherein the gasket assembly additionally includes an intermediate element of thermally insulating material supported by the retaining means.

9. A curtain wall structure in which the frame members carry sealing gasket assemblies along their exterior faces to receive marginal portions of curtain panels which close apertures in the framework bounded by the frame members, wherein each gasket assembly comprises an inner sealing element on the exterior face of the frame member, an outer sealing element spaced from the inner sealing element towards the exterior of the structure and an intermediate element of thermally insulating material which supports the outer sealing element and is itself supported from the frame member by retaining means carried by the frame member.

10. A structure according to Claim 8 or 9 wherein the intermediate element extends without interruption from the inner sealing element to the outer sealing element.

11. A structure according to Claim 8 or 9 wherein the intermediate element is separate from the inner sealing element.

12. A structure according to any one of Claims 8 to 11 wherein the gasket assemblies carried by frame members which form a common boundary between two adjacent apertures in the framework include a pair of said inner sealing elements disposed at opposed edges of the exterior face of the frame member, and a pair of said outer sealing elements correspondingly arranged.

13. A structure according to Claim 11 wherein the pair of outer sealing elements are integrally united with one another.

14. A structure according to any one of the preceding claims wherein pressure plates bearing on said outer sealing elements are carried by said retaining means.

15. Any novel feature or novel combination of features disclosed herein and/or in the accompanying drawings.