GB2309249A

GB2309249A - Glazing gasket with a sealing lip formed of two materials of different colours

Info

Publication number: GB2309249A
Application number: GB9601086A
Authority: GB
Inventors: Paul Edward James
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-01-19
Filing date: 1996-01-19
Publication date: 1997-07-23
Anticipated expiration: 2016-01-19
Also published as: GB9601086D0; GB2309249B

Description

GLAZING GASKET The present invention relates to a glazing gasket.

Glazing gaskets are employed in window installations to provide a weather seal between a frame and a glass pane, or a double pane unit in the case of double glazing, installed in the frame. Present day frames are commonly assembled from extruded olastics strips and each strip incorporates a recess to receive a gasket having a lip which bears against an adjacent pane.

The gasket itself is usually extruded from an elastomeric material sufficiently resilient to provide effective sealing contact with the installed pane and resistant to ultraviolet degradation. The material is normally black, but this is not always aesthetically desirable if, for example, the frames themselves are enamelled in another colour.

Consequently, gaskets have been produced in colours conforming to frame colours, for example in white. A problem with white or any other light colour, however, is that it provides a contrasting background for dirt or other contaminants which might otherwise be invisible against black.

Regardless of the integrity of the sealing contact of the gasket lip with a pane it is inevitable that cleaning residues or dirt accumulate behind the lip, thus between the lip and the pane. These accumulations are evident from the other side of the window installation, thus from inside a room or compartment provided with the window, and are unsightly. As a result, gaskets in white or other light colours, however desirable from the viewpoin of exterior aesthetics, are not widely used.

It would thus be desirable to provide a glazing gasket which may permit use of a light colour for colour-matching or colour-harmonising purposes, but which is not susceptible to the above-mentioned problems of unsightliness. Other objects and advantages of the invention will be apparent from the following description.

According to a first aspect of the invention there is provided a glazing gasket comprising a body portion for locating the gasket in a glazing installation and a resilient sealing lip portion for sealing relative to a glazing pane of the installation, wherein the lip portion comprises a resilient material of a dark colour at a first face thereof intended to face towards the pane and a resilient material of a lighter colour at a second face thereof intended to face away from the pane.

In the case of such a gasket the dark colour, for example black, renders any contaminants ingressing between the lip portion and pane effectively invisible, whereas the lighter colour, for example white, against which contaminants might otherwise be highly visible is presented only to the exterior of the glazing installation and can be easily cleaned if or when needed. The lighter colour can be matched to, for example, the colour of the frame. The presence of a constituent resilient material of each of the two colours in the lio portion means that there is no risk of exterior discolouration due to coating loss which could occur if the exterior face of the lip portion was simply painted.

Preferably, the two resilient materials of the lip portion are directly bonded together, so that the lip portion consists solely of the materials of the two colours. If the materials are generally compatible for bonding purposes a securely structured lip portion free of any risk of delamination during the service life of the gasket is obtained.

For preference the body portion of the gasket is composed of the resilient material of the dark colour and thus can be formed integrally with the correspondingly coloured material part of the lip portion.

At least one of the resilient materials is preferably an elastomeric material, for example, a thermoplastic elastomer. Thermoplastic elastomers are weather-resistant, easy to process and retain their resilient properties in the longer term notwithstanding the substantial temperature changes to which glazing installations are frequently exposed. They also can have a stain-resistant surface property, which is of advantage for white or other light colours, and resist colour migration, which is of particular importance in the case of adjoining light and dark colours.

In constructional terms, the first face of the lip portion is preferably convex and the second face concave, which results in a lip portion shape able to provide areal rather than merely lineal contact with the pane. The lip portion can taper in direction from a base thereof connected with the body portion to a free edge, so that there is sufficient mass in the lip portion for the purposes of strength and resilience and so that the free end of the lip can be relatively sharp and thus run onto the pane surface with only a very slight step, in effect, a flush transition.

The body portion can include a strip of expansion-resistant material to resist elongation of the gasket during installation.

According to a second aspect of the invention there is provided a glazing installation comprising a frame, a glazing pane mounted in the frame, and a glazing gasket according to the first aspect of the invention, wherein the body portion of the gasket is located in the frame and the first face of the lip portion of the gasket bears against the pane.

According to a third aspect of the invention there is provided a method of manufacturing a gasket of the first aspect of the invention, the method comprising the steps of extrusion moulding a first strip of resilient material having the dark colour and defining the body portion and part of the lip portion including the first face thereof and a second strip of resilient material having the lighter colour and defining the remaining part of the lip portion including the second face thereof, and bringing the two strips together in such a relationship while the constituent materials thereof are still in a molten or partly molten state that the strips bond together to form the complete lip portion.

Such a method results in a secure and permanent bond of the two members so that the lip portion has a homogeneity of construction which, in relation to the stresses likely to be encountered in use, is little different from that available from formation of the lip portion from a single material. In particular, there is no likelihood of separation of the two materials of the lip portion as a result of flexure during handling and installation.

According to a fourth aspect of the invention there is provided plant for use in carrying out the above method, the plant comprising an extrusion die having a first passage corresponding in cross-sectional shape to that of the first strip, a second passage corresponding in crosssectional shape to that of the second strip, a third passage formed by merging of the first and second passages and corresponding in crosssectional shape to that of the body and lip portions in the finished gasket, and a respective feed connected to an entry end of each of the first and second Passages.

Embodiments and examples of the present invention will now be more particularly described with reference to the single figure of the accompanying drawing, which is a schematic sectional view of a part of a glazing installation incorporating a gasket embodying the invention.

Referring now to the drawing figure there is shown part of a window installation comprising a double-glazing unit 10 mounted in a frame 11 and with an exterior glazing gasket 12 embodying the invention disposed between the frame and the unit, in particular at the exterior side of a building wall, vehicle body or the like fitted with the installation. The frame 11 is composed of extruded aluminium frame members 13, part of only one of which is shown. Each frame member essentially consists of an arrangement of webs providing interior-facing and exterior-facing surfaces, a seat for the wall material, vehicle bodywork or other support, a seat for the glazing unit, a mounting recess for the exterior gasket 12 and a further mounting recess for an interior gasket (not shown).The glazing unit 10 comprises two parallel and hermetically interconnected glass panes 14, only one of which is shown, and is located in the associated seat in the frame. The seat for the glazing unit is bounded at the interior side and exterior side of the frame by bevelled flanges 15, only the exterior one of which is illustrated. The flanges are each disposed at a spacing from the adjacent pane of the glazing unit. The thus formed spaces represent the mounting recesses for the gaskets. The shapes of the recesses generally differ from each other, as do the shapes of the gaskets themselves.

The exterior gasket 12 is shown installed and consequently somewhat deformed by comparison with its relaxed state when not installed. The gasket 12 comprises a resilient body portion 16 and a resilient lip portion 17 integrally connected with the body portion.

The lip portion 17 resiliently bears against the exterior surface of the exterior pane 14 to provide a weather seal and is disposed entirely outside the associated mounting recess. The body portion 16 is received in the recess so as to locate the gasket in position. In order to resist removal from the recess, the body portion has a T-shaped projection 18 engaged in an undercut groove in the flange 15. The body portion also includes two underlying sealing lips 19 bearing against the pane and reinforcing the sealing effect provided by the lip portion 17.

The lip portion 17 has a convex face towards the pane and a concave face away from the pane. The concavity and convexity are present, but of less pronounced curvature, in the relaxed state of the gasket. The lip portion tapers in direction towards its free edge 20.

The taper is such that the free edge 20 is relatively sharp, so that a smooth transition to the pane exterior surface is provided. In the opposite direction, the lip portion has a rounded bead 20 extending over and pressurably bearing on the top of the flange 15.

The body portion 16 of the gasket and a lower part 17a of the lip portion 17, in particular the part defining the convex face of the lip portion, consist of an extruded strip of a thermoplastic elastomer material coloured black and having good tensile strength and resistance to ageing or temperature-induced change, for example VITACOM TPE 4050101 (Trade Mark) meeting British Standard BS 7412:1991. The remaining part 17b of the lip portion, in particular the part defining the concave face, consists of an extruded strip of a thermoplastic elastomer material coloured white and having essentially the same properties, for example VITACOM TPE 4050-201 (Trade Mark) meeting the same Standard.

The two strips are bonded together by material fusion in the molten state to form a permanent connection. As can be seen in the figure, the parts 17a and 17b are shaped so that the upper part of white material contains the bead 21 and so that the parts meet in the region of the free edge 20. The black material part in fact stops just short of the free edge, so that no black colour is visible at the exterior.

The gasket formed by the bonded clastomeric strips of different colour is, in use, cut to length in dependence on frame dimensions. In order to resist elongation of the gasket during installation and subsequent retraction, which could result in gaps at the frame corners, a strip 22 of expansion-resistant material such as polypropylene is incorporated in the body portion 16, the elastomeric material of which is adhesively bonded to the strip 22.

The glazing gasket 12 with the construction described above provides an effective weather seal and shock protection in relation to the exterior pane of the glazing unit 10 and presents, to the exterior, only the colour white. This colour is aesthetically more harmonious with unpainted natural aluminium frame profiles and generally with usual externally colourings of buildings, for which white or other light colours are conventional. From the inside of the building only the black underside of the lip portion is apparent and there is thus no background against which ingressing dirt or other residues will be visible. The essential entry of contaminents between the lip portion and pane tends to be inevitable regardless of the effectiveness of the seal against the pane surface.

The interior gasket of the window installation, although differently shaped, can similarly include a multicolour sealing lip portion of similar construction to the lip portion 17.

Colours other than white and black are, of course, possible. The essential distinction between the colours is that the inward face of the lip portion should be a dark colour concealing residues and the outward face a lighter colour selected for aesthetic compatability with its surround.

The described and illustrated shape of the gasket 12 is merely by way of example and is appropriate to a double-glazed window installation in a building. Singly and doubly glazed window installations require weather sealing and cushioned mounting in many other applications, including land vehicles, ships and aircraft and the gasket is usable in these and other contexts.

Production of the gasket 12 can be carried out by extruding in parallel the strip of black elastomeric material defining the body portion 16 and the part 17a of the lip portion and the strip of white elastomeric material defining the part 17b of the lip portion. Extrusion is carried out with use of a die having a first passage for the black strip, a second passage for the white strip, and a third passage formed by merging of the first and second passages and corresponding to the final cross-section of the body and lip portions of the gasket. The two strips, while still in a molten state, are brought together in the third passage and their constituent materials fuse at the interface of the parts 17a and 17b so as to form the complete lip portion 16. The materials are disposed under pressures which are matched or otherwise in a predetermined relationship preventing displacement of either material by the other in the third section. The die preferably includes heating means to keep the strips at the extrusion temperature of about 1800C. A fourth passage for the strip of expansion-resistant material can also be present in the die and merge with the third passage to form a fifth section corresponding to the final cross-section of the gasket inclusive of the strip 22. Each of the first, second and fourth passages is connected at an entry end thereof to a respective feed bore coupled to a pressure feed of the respective material in molten state.

The die can be formed from a series of five assembled plates, in which the first plate has feed bores for the first passage, the second plate has the first passage only, the third plate has the first passage and also the second passage, which passages converge at or near the junction with the fourth plate, the fourth plate has the third passage (combined first and second passages) and also the fourth passage, which passages converge at or near the junction with the fifth plate, and the fifth plate has the fifth passage (combined third and fourth passages). The feed bores for the second and fourth passages can be formed by grooves machined into the mating faces of the second/third plates and the third/fourth plates.

At least one duplicate set of passages can be present in the die so that at least one additional gasket can be produced at the same time. In that case common feed bores can be provided for corresponding passages in the sets.

The strips bonded together in this manner are highly resistant to delamination and the lip portion can be flexed in all directions, without exhibiting any tendency to separation of the two elastomers.

Claims

1. A glazing gasket comprising a body portion for locating the gasket in a glazing installation and a resilient sealing lip portion for sealing relative to a glazing pane of the installation, wherein the lip portion comprises a resilient material of a dark colour at a first face thereof intended to face towards the pane and a resilient material of a lighter colour at a second face thereof intended to face away from the pane.

2. A gasket as claimed in claim 1, wherein the two resilient materials of the lip portion are directly bonded together.

3. A gasket as claimed in claim 1 or claim 2, wherein the body portion is composed of the resilient material of the dark colour.

4. A gasket as claimed in any one of the preceding claims, wherein at least one of the resilient materials is an elastomeric material.

5. A gasket as claimed in claim 4, wherein the elastomeric material is a thermoplastic elastomer.

6. A gasket as claimed in any one of the preceding claims, wherein the first face is convex and the second face is concave.

7. A gasket as claimed in any one of the preceding claims, wherein the lip portion tapers in direction from a base thereof connected with the body portion to a free edge thereof.

8. A gasket as claimed in any one of the preceding claims, wherein the dark colour is black.

9. A gasket as claimed in any one of the preceding claims, wherein the lighter colour is white.

10. A gasket as claimed in any one of the preceding claims, comprising a strip of expansion-resistant material incorporated in the body portion.

11. A glazing gasket substantially as hereinbefore described with reference to the accompanying drawing.

12. A glazing installation comprising a frame, a glazing pane mounted in the frame, and a glazing gasket as claimed in any one of the preceding claims, wherein the body portion of the gasket is located in the frame and the first face of the lip portion of the gasket bears against the pane.

13. A method of manufacturing a glazing gasket as claimed in any one of claims 1 to 11, comprising the steps of extrusion moulding a first strip of resilient material having the dark colour and defining the body portion and part of the lip portion including the first face thereof and a second strip of resilient material having the lighter colour and defining the remaining part of the lip portion including the second face thereof, and bringing the two strips together in such a relationship while the constituent materials thereof are still in a molten or partly molten state that the strips bond together to form the complete lip portion.

14. A method as claimed in claim 13, wherein the temperature of the members during the step of extruding is substantially 180".

15. A method as claimed in claim 1 and substantially as hereinbefore described.

16. Plant for use in carrying out the method as claimed in claim 13, comprising an extrusion die having a first passage corresponding in cross-sectional shape to that of the first strip, a second passage corresponding in cross-sectional shape to that of the second strip, a third passage formed by merging of the first and second passages and corresponding in cross-sectional shape to that of the body and lip portions in the finished gasket, and a respective feed connected to an entry end of each of the first and second passages.

17. Plant as claimed in claim 16, comprising means to heat the die to cause the temperature of the members therein to be at substantially 1800C.

18. Plant as claimed in claim 16 or claim 17 and for use in carrying out the method as claimed in claim 10, wherein the die has a fourth passage corresponding in cross-sectional shape to that of the strip of expansionresistant material, a fifth passage formed by merging of the third and fourth sections and corresponding in cross-sectional shape to that of the body and lip portions inclusive of the strip of expansion-resistant material in the finished gasket, and a respective feed connected to an entry end of the fourth passage.