GB2287246A - Attaching trim finishers to glass using adhesive - Google Patents

Abstract

A process for applying trim finishers (10) to a glass component (11) includes: locating the trim finisher (10) in a jig (15) so that the front surface of the trim finisher (10) is supported by the jig (15) and the trim finisher (10) is located in the plane and transversely of the plane of the component (11); applying adhesive (20) to the rear surface of the trim finisher (10) and/or the opposed surface of the component (11); and bringing the component (11) into engagement with the trim finisher (10) in a manner which will allow the component (11) to flex to accommodate any tolerance variations in the curvature or thickness of the component (11), thereby providing a good fit with the trim finisher (10). <IMAGE>

Description

PROCESS FOR THE APPLICATION OF TRIM FINISHERS TO GLASS The present invention relates to a process of applying trim finishers to glass and in particular, but not exclusively, to the production of glass components for the automotive industry.

In the automotive industry it is normal to apply metal or plastic trim finishers around the periphery of windows etc. Hitherto, this has normally been achieved by means of trim clips, which are secured to the body of the vehicle. The glass, for example, the windscreen of the vehicle, is first fitted to the vehicle, possibly by bonding, and the trim finisher is applied to the trim clips to provide a quality fit to the glass and body.

This method of locating the trim finisher requires many fixings and accurate location of the fixings. The complication of assembly can cause reliability, fit and finish problems.

Trim finishers applied in this way must exhibit low thermal expansion, which necessitates the use of plastics with high levels of glass filling.

Such materials require many coats of paint to cover flow lines and glass imperfections at the surface of the component. Alternatively, Co- extrusions of PVC and steel may be used, the steel being used to support the PVC finish and to permit the extrusion to be clipped to the vehicle.

Trim finishers which are clipped in place are usually provided with soft lip formations which may be easily deformed to provide a seal with the glass.

It has been alternatively proposed to apply trim finishers to the glass by an encapsulation method in which the trim finisher is moulded directly onto the glass surface. This operation comprises clamping the glass in a tool that defines a mould cavity for the trim finisher and injecting liquid polyurethane into the cavity so that upon solidification, it will adhere to the glass surface. With this process, the fit of the glass in the tool is critical, as any gaps between the glass and tool will allow leakage of the liquid polyurethane. As a consequence, it is necessary to use high clamping loads and any distortion of the glass will result in the glass breaking when the tool clamp loads are applied.

This encapsulation process therefore requires the glass to be formed to very close tolerances. This is possible with flat glass or with small curved components. However, with large components or complex curvature, the required tolerances cannot be maintained on a high volume production basis, where the normal tolerances would be i 1 mm in 300 mm trueness, 3 mm on curvature and + 0.2 mm on thickness.

It is not consequently possible to use the encapsulation process for large glass components of complex curvature, such as those used in the automotive industry, on a viable commercial basis.

In accordance with the present invention it is proposed to bond the trim finisher to the glass. While it is not new to bond components to glass, the present process permits the accurate location of the trim finisher, while allowing for normal tolerance variations in the curvature and thickness of the glass, thereby permitting a good finish to be obtained on a high volume production basis.

According to one aspect of the present invention a process for the application of trim finishers to glass components comprises: locating the trim finisher in a jig so that the front surface of the trim finisher is supported by the jig and the trim finisher is located in the plane and transversely of the plane of the component; applying adhesive to the rear surface of the trim finisher and/or opposed surface of the glass; and bringing the glass into engagement with the trim finisher in a manner which will allow the glass to flex to accommodate any tolerance variations in the curvature or thickness of the glass, thereby providing a good fit with the trim finisher.

In accordance with the preferred embodiment of the invention, the glass is clamped by vacuum clamping means, which engages the side of the glass to which the trim fastener is to be bonded and which pulls the glass into engagement with the trim finisher which is supported in the jig.

Preferably the trim finisher is provided with a rigid lip formation which is intended to engage the surface of the glass. The jig is arranged so that the lip formation extends proud of the jig and the glass may be pulled down into engagement with the lip formation.

The adhesive is preferably of high viscosity which will rapidly provide a bond sufficient to maintain engagement between the trim finisher and glass, when the load applied to the glass is removed. Butyl or polyurethane adhesives are suitable for this purpose. These adhesives solidify rapidly on cooling and provide a strong initial bond. Subsequent curing provides full bond strength, particularly with polyurethane adhesive.

Alternatively, where high production rates are not of primary significance, other adhesive may be used which take longer to reach the appropriate bond strength, the glass being maintained under load until the required bond strength is achieved.

The trim finishers may be of solid or hollow configuration and may be formed by injection moulding, extrusion, coextrusion or pressing. Suitable sections may be fabricated into the required structure or, for example, a full frame may be moulded in a single part.

An embodiment of the invention is now described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the apparatus used in accordance with the present invention; Figure 2 is a section along the line ll - II of Figure 1; Figure 3 is a section along the line Ill - Ill of Figure 1; Figure 4 is an enlarged section of the apparatus shown in Figure 1, prior to clamping the glass; and Figure 5 is a view similar to Figure 4 of a section of the apparatus shown in Figure 1, with the glass clamped.

As illustrated in the accompanying drawings an apparatus for applying a trim finisher 10 to a piece of glass 11, comprises a jig 1 5. The jig 1 5 defines a cavity 16 (better seen in Figures 4 and 5) the surface of the cavity 16 corresponding to the front face of the trim finisher 10. The cavity 16 provides a vertical support for the trim finisher 10 and also locates the trim finisher 10 laterally. The trim finisher 10 is located in the cavity 16, a rigid lip formation 13 extending above the upper surface of the jig 15. As illustrated in Figures 1 to 3, the upper surface of the jig 15 defines a plane of complex curvature, that is curved in two dimensions, which corresponds to the nominal curvature of the glass 11.

A continuous bead of butyl adhesive 20 is applied around the rear face of the trim finisher, adjacent to the lip formation 13. The adhesive bead, which is heated to provide a plastically deformable adherent mass, may be applied by means of a conventional applicator, undisturbed access being provided to the rear face of the trim finisher 10.

The sheet of glass 11 is then located in place on top of the trim finisher 10 and is engaged by a series of vacuum cups 25 which are located internally around the periphery of the jig 15. As illustrated in Figures 4 and 5, the vacuum cups 25 are of corrugated construction and are formed from a flexible resilient material. The cups 25 are connected to vacuum pipes 26 by means of which they may be evacuated.

Light pressure on the glass will cause the peripheries 27 of the vacuum cups 25 to sealingly engage the surface of the glass 11, the seal being maintained by a vacuum in the cups 25. Increasing the vacuum in the cups 25 will cause the cups to compress pulling the glass 11 down and deforming the bead of adhesive 20. The glass 11 is pulled down until the surface of glass 11 engages the rigid lip formation 1 3. The glass 11 is flexed to accommodate any tolerance variations in its trueness, curvature or thickness, so that engagement between glass 11 and lip formation 13 is achieved along the full length of the trim finisher 10.

The adhesive bead 20 cools rapidly upon engagement with the glass 11 and forms a bond between the glass 11 and trim finisher 10, which will be sufficient to maintain contact between the glass 11 and lip 13 of the trim finisher 10 when the clamping load on the glass 11 is released by permitting air to enter the vacuum cups 25.

By using the vacuum cups as described above, localised stressing of the glass 11 is avoided, the flexing of the glass being spread across the full area, thereby reducing the risk of breakage.

Various modifications may be made without departing from the invention. For example, instead of using vacuum cups, other means which avoid local stressing of the glass may be used to apply the load. For example, an air bag or similar means may be used to apply the load from the upper surface of the glass. In place of the adhesive bead, a compressible double sided adhesive tape may be used.

Claims (15)

1. A process for the application of trim finishers to glass components comprising: locating the trim finisher in a jig so that the front surface of the trim finisher is supported by the jig and the trim finisher is located in the plane and transversely of the plane of the component; applying adhesive to the rear surface of the trim finisher and/or opposed surface of the glass; and bringing the glass into engagement with the trim finisher in a manner which will allow the glass to flex to accommodate any tolerance variations in the curvature or thickness of the glass, thereby providing a good fit with the trim finisher.

2. A process according to Claim 1 in which the jig provides a cavity, the surface of the cavity corresponding to the front face of the trim finisher.

3. A process according to Claim 2 in which the cavity in the jig provides for transverse location of the trim finisher.

4. A process according to any one of the preceding claims in which the trim finisher has a lip formation for engagement of the glass surface, the lip formation extending proud of the jig when the trim finisher is located in the jig.

5. A process according to any one of the preceding claims in which vacuum cups engage the glass and draw the glass down into engagement with the trim finisher.

6. A process according to Claim 5 in which vacuum cups are provided internally around the periphery of the jig.

7. A process according to Claim 5 or 6 in which the vacuum cups are of corrugated construction such that they will compress as they are evacuated, moving the glass towards the trim finisher.

8. A process according to any one of the preceding claims in which an adhesive of high viscosity is used.

9. A process according to Claim 8 in which a butyl or polyurethane adhesive is used.

10. A process according to Claim 8 or 9 in which a bead of adhesive is applied to the rear surface of the trim finisher or to the opposed surface of the glass.

11. A process according to any one of the preceding claims in which the trim finisher is of solid or hollow configuration.

12. A process according to any one of the preceding claims in which the trim finisher is formed by injection moulding, extrusion, co-extrusion or pressing.

13. A process according to any one of the preceding claims in which the trim finisher is moulded in a single part.

14. A process substantially as described herein, with reference to the accompanying drawings.

15. A glass component with trim finisher bonded thereto, formed in accordance with the process claimed in any one of Claims 1 to 14.