WO2007139372A1

WO2007139372A1 - Assembly and method for protecting a windscreen against damage

Info

Publication number: WO2007139372A1
Application number: PCT/NL2006/000269
Authority: WO
Inventors: Frank Reinier Theo Ric Bouwman
Original assignee: Bouwman, Marcus, Jacobus, Antonius
Priority date: 2006-05-26
Filing date: 2006-05-26
Publication date: 2007-12-06

Abstract

The present invention is related to an assembly for protecting a windscreen against damage, the assembly comprising an inner layer of a first material arranged on the windscreen, an outer layer of a second material arranged at least partly and preferably wholly on the inner layer, wherein the inner and outer layer together distribute and absorb impact energy. The present invention is further related to a method for arranging a protective assembly on a windscreen, the method comprising of preparing a windscreen, arranging an inner layer of a first material on the prepared windscreen and arranging an outer layer of a second material over at least a part of the inner layer, as well as a windscreen provided with such protective assembly.

Description

ASSEMBLY SJSfD METHOD FOR PROTECTING A WINDSCREEN AGAINST

DAMAGE

The present invention relates to an assembly for protecting a windscreen, and in particular a windscreen of a motor vehicle, against damage. The invention further relates to a method for arranging such an assembly on a windscreen, and a windscreen comprising such an assembly.

Stone chippings and other impacts often result in relatively limited damage at the point of impact, also referred to as a ^Λchip' , on the windscreen. It sometimes occurs that such limited, local damage deteriorates into a crack or break. Although limited damage in the form of a chip can often still be repaired, this is not usually the case with cracking or breaking. Cracks or breaks consequently often result in necessary replacement of the windscreen, with the associated costs for the owner of the motor vehicle.

Research into damage to windscreens has shown that the risk of cracking or breaking becomes greater the closer the chips are situated to an edge of the windscreen. The peripheral area where the windscreen is mounted, and particularly where it is glued to the bodywork of the vehicle, has a relatively limited resilience and an increased mechanical stress compared to the rest of the windscreen. In the most common cases this is an area at a distance of up to about 15 cm from the position of glueing in both inward and outward direction. The reduced resilience and the greater mechanical stress of this peripheral area have the result that, in the case of an impact, this area is less able to absorb the forces to which the screen is subjected compared to the rest of the windscreen. As a result limited damage to the windscreen will in this peripheral area regularly deteriorate into cracking, and will entail the necessary cost of replacing the windscreen.

It is an object of the present invention to provide an assembly and method with which a windscreen can be protected against damage caused by for instance stone chippings, particularly in order to prevent windscreen replacement being necessary. The stated object is achieved with the assembly according to the invention, wherein an inner layer of a first material is arranged on the windscreen; and a second layer of a second material is arranged at least partly and preferably in covering manner on the inner layer, wherein the inner and outer layers together distribute and absorb the impact energy.

Since the inner and outer layer together distribute and absorb the impact energy, their co-action provides an assembly with a very good protection in relation to the thickness, and therefore an effective protection of the windscreen lying thereunder, whereby the damage caused by chippings or other similar impacts is reduced relative to a windscreen on which the assembly according to the present invention is not arranged or fixed.

In a preferred embodiment the assembly comprises an outer layer which substantially distributes the impact energy, and an inner layer which substantially absorbs the impact energy distributed by the outer layer. This interaction between the inner and outer layer provides an effective energy distribution and absorption. The outer layer receives the flying chippings first, will deform elastically and will in this manner distribute the energy to a greater surface area of the inner layer, which will further absorb the impact energy. Furthermore, through the use of an inner and an outer layer, the outer layer can protect the inner layer against environmental influences . In a further preferred embodiment the properties of the inner layer are modified ^" for an improved energy absorption. In the choice of material for the inner layer it is possible to concentrate mainly on the energy absorption properties, such as for instance the damping properties of the layer, while the susceptibility to weather influences is substantially of secondary importance since the outer layer protects this inner layer from them.

By giving the inner layer a substantially transparent form it is possible to limit the effect on the field of vision of the driver and possible other people present in the vehicle.

Examples of materials which are suitable for forming the inner layer are for instance plastics such as polyether, polyethylene, polyurethane, silicones and derivatives thereof. It is particularly recommended that the inner layer is embodied in silicones.

In a further preferred embodiment the inner layer preferably comprises UV-resistant material to prevent a degeneration of the material properties as a result of UV-radiation. Such a UV protection can for instance be provided by adding additives to the material of the inner layer.

In yet a further preferred embodiment the inner layer has a thickness in the order of magnitude of 0-5 mm, preferably about 0-2 mm, and more preferably substantially 0-1.5 mm. It is particularly recommended that the inner layer has a thickness of 0.5-2 mm, such as for instance 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0 mm. Most recommended is that the inner layer has a thickness¹ of 1.5-2 mm, such as 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0 mm.

In a further preferred embodiment the outer layer comprises a material having a hardness in the order of magnitude of the hardness of glass, such as for instance an outer layer formed from a plastic such as polycarbonate or a derivative thereof. An outer layer with such a hardness distributes the impact energy over a large area of the underlying inner layer, while this hardness - in combination with the damping properties of the inner layer - will generally be sufficient to prevent permanent damage to the outer layer as a result of chippings .

In yet another preferred embodiment the outer layer is substantially transparent and/or manufactured from

UV-resistant material. If both the inner layer and the outer layer are substantially transparent, the field of vision of the driver will be influenced minimally. UV resistance of the outer layer will increase the lifespan of this outer layer and also protect the inner layer from the harmful effects of UV-radiation .

In yet a further preferred embodiment the outer layer is substantially preformed in order to further facilitate arranging thereof. The invention further relates to a method for protecting a windscreen, wherein the method comprises of: preparing a windscreen; arranging an inner layer of a first material on the prepared windscreen; and - arranging an outer layer of a second material over at least a part of the inner layer.

The assembly for protecting a windscreen as described above is arranged by placing an inner and an outer layer on the windscreen. In a preferred embodiment of the method the preparation of the windscreen comprises at least cleaning thereof. Cleaning and degreasing the screen prevents, after arranging of the inner layer, particles coming to lie between this layer and the windscreen. The adhesive properties are moreover improved by degreasing the windscreen. The preparation of the windscreen can further comprise of clearing frames, windscreen wipers and scuttle panel as much as possible.

In a further preferred embodiment of the method the arranging of the inner layer comprises of moistening the windscreen, positioning the inner layer and removing liquid from the windscreen. Through moistening of the windscreen the inner layer can be readily displaced over the windscreen and thus precisely positioned, before the moisture is removed from thereunder by wiping in order to prevent the formation of possible air bubbles and in this manner to end positioning of the inner layer and complete the arrangement. In a preferred embodiment the arranging of the outer layer comprises of arranging a substantially preformed outer layer. Because the outer layer is preformed, the arranging process is further simplified.

In an alternative preferred embodiment of the method the arranging of the outer layer comprises of applying a film in substantially liquid state to the inner layer; and curing the applied film. A uniform layer with a smooth transition to parts not covered by the inner layer is obtained by applying a film in substantially liquid state. Curing of the applied film converts this from a film in substantially liquid state to a layer in substantially solid state.

In a further preferred embodiment of the method the outer layer is polished in order to obtain a substantially smooth transition between the protective means and the windscreen. This smooth transition is desired for the purpose of obtaining a minimal image distortion in the transition zone. Furthermore, a smooth transition also has aesthetic and practical advantages, such as for instance preventing obstructions during wiping or scraping of the windscreen.

According to a further preferred embodiment of the method a template is applied for arranging the inner and/or outer layer. Different types of cars will comprise windscreens of different dimensions, shapes and curves. The arranging of protective means can be simplified by making use of a template for each specific type of windscreen.

In a further preferred embodiment of the method the inner layer is attached to the windscreen by means of for instance affixing, adhesion/glueing or other types of application.

In yet a further preferred embodiment of the method the outer layer - in substantially liquid state - is applied by means of spraying, atomizing, dripping, dipping or rolling.

In another preferred embodiment of the present invention an already preformed outer layer of a hard material such as polycarbonate is filled with a fluid inner layer which, after being applied, will cure in the template formed by the preformed outer layer. The assembly according to the present invention which can be fixed or glued integrally to the windscreen is hereby provided.

The present invention further relates to a windscreen provided with an assembly which can be arranged according to the above described method.

In a preferred embodiment of this windscreen the thickness of the inner layer decreases in upward direction along the windscreen. In general the heavier stones will usually strike the lower part of the windscreen, and the upper part of the windscreen will generally only be struck by lighter stones. Because the impact energy of a large stone will be higher than that of a small stone - at the same collision speed - it is therefore desirable that the thickness will be sufficient to absorb the impact energy of the heavy stones at least on the lower side of the windscreen - where relatively the most heavy stones are expected. From the viewpoint of the required quantity of material, and also from an aesthetic viewpoint, it is recommended to vary the thickness of the layer in accordance with the required protection, whereby the thickness of the inner layer will decrease in upward direction along the windscreen. It is of course also possible to provide users with the option of choosing between different thicknesses such as light/normal/extreme, wherein this thickness will be arranged evenly over the whole protective assembly. Light then for instance corresponds with a thickness in the order of magnitude of 0-1.5 mm, normal with a thickness in the order of magnitude of 0-2 mm and extreme with a thickness in the order of magnitude of 0-5 mm. On the lower side of the screen, where aesthetic considerations are subordinate to the protection, the layer can be provided with a thickness of for instance 2 mm or for instance 5 mm. On the upper side, where the relatively lighter stones are expected, a thickness in the order of magnitude of 1.5 mm is generally deemed sufficient .

In a further preferred embodiment the inner layer extends from the lower side of the windscreen in upward direction over a distance such that the lower part of the windscreen exposed to chippings is covered. Simply arranging a protective layer close to the periphery of the windscreen will not be sufficient - particularly on the bottom part of the screen - since it is common for a large part of the windscreen to continue under the hood, possibly behind the scuttle panel. If the layer is then arranged only close to the periphery of the screen, it may be the case, particularly on the lower side, that there is insufficient protection for the part exposed to chippings on the lower side of the windscreen.

In addition, it is advisable to apply the layer everywhere where the windscreen is provided with an adhesive or primer layer, since damage is difficult to discern in this adhesive or primer layer.

In a further preferred embodiment the thickness of the inner layer decreases in the direction of the centre of the windscreen. As chippings strike the windscreen further in the direction of the centre of the windscreen, the windscreen will be more resilient and a crack will therefore result less readily from a chip. Furthermore, the material required is limited by the decrease in the thickness where it is no longer necessary for protection, and an aesthetic and practical whole is obtained by a smooth transition.

An exemplary embodiment is explained further in the following description with reference to the drawings, in which: Figure 1 shows a perspective view of a vehicle provided with a windscreen on which the assembly for protecting the windscreen against damage according to the present invention is arranged;

Figure 2 is a perspective view of a part of the windscreen;

Figure 3 is a perspective detail view of the upper corner of the windscreen shown in figure 2;

Figure 4 is a perspective view of the lower corner of the windscreen of the windscreen shown in figure 3; Figure 5 shows a side view of a windscreen provided with an assembly comprising a first configuration of the inner layer and the outer layer. Figure 6 shows a side view of a windscreen provided with an assembly comprising a second configuration of the inner layer and the outer layer.

The preferred embodiment as shown in figure 1 comprises a car 1 provided with a windscreen 2. The car shown in figure 1 is provided with a windscreen 2 with a lower side 2a, an upper side 2c and sides 2b. On this windscreen is arranged an assembly 3 for protecting the windscreen against damage as a result of chippings . Figure 2 shows an enlarged view of a portion of windscreen 2. Arranged on windscreen 2 is a protective assembly 3, which in a preferred embodiment comprises a greater thickness on the lower side 2a of windscreen 2 than on upper side 2c of windscreen 2. Figures 3 and 4 show a further enlargement of respectively upper side 2c and lower side 2a of windscreen 2, wherein it is shown in detail that protective assembly 3 is thinner on the upper side 2c than on the lower side 2a of windscreen 2 shown in figure 4. Figures 5 and 6 show a schematic side view of a windscreen 2 provided with a protective assembly 3, which comprises an inner layer 4 and an outer layer 5. As shown in figure 5, the outer layer can be arranged on inner layer 4, although also possible is the configuration shown in figure 6, wherein outer layer 5 encloses inner layer 4 and is also in contact with windscreen 2.

Outer layer 5 is substantially harder than inner layer 4 and, when exposed to chippings, will be the first to receive the projectile, will substantially or wholly deform elastically as a result of the deformation of inner layer 4, wherein outer layer 5 substantially distributes the impact energy and inner layer 4 substantially absorbs over an increased area the impact energy distributed by the outer layer.

In the preferred embodiment shown in figure 6, outer layer 5 protects inner layer 4 against weather influences . In this assembly it is desirable that at least the outer layer is UV-resistant in order to prevent degeneration of the material properties as a result of exposure to UV-radiation. In the configuration shown in figure 5 the inner layer 4 will also be exposed - at least partly - to weather influences, whereby UV-resistance of inner layer 4 is also preferred in this configuration.

By giving both inner layer 4 and outer layer 5 a transparent form the assembly 3 will have a limited to negligible effect on the field of vision of the passengers of car 1.

Although assembly 3 can be arranged over the entire surface area of windscreen 2 it is recommended - particularly from a material-saving viewpoint - to provide windscreen 2 with protective assembly 3 only on the most vulnerable areas - comprising the less resilient edges 2a, 2b and 2c. In order to also minimize the influence on the field of vision of the passengers of car 1 when protective assembly 3 is partially arranged on windscreen 2 of car 1, it is recommended to have assembly 3, comprising inner layer 4 and outer layer 5, transpose uniformly into windscreen 2. A possible distortion of the field of vision of the passengers is minimized by preventing sharp edges between layers 4 and 5 and windscreen 2.

The method for arranging assembly 3 on windscreen 2 will now be described. Windscreen 2 is firstly cleaned and preferably degreased. Windscreen 2 is then moistened and inner layer 4 is placed on the moistened windscreen 2. This preferably takes place by means of a template which is suitable for this specific type of windscreen. If a template is not available, inner layer 4 can also be arranged manually. Use can for instance be made for this purpose of a roller with a standard dimension, of for instance 15 centimetres in width, of the material of inner layer 4 wound thereon. The desired width can be varied by means of trimming, optionally when the foil of inner layer 4 is arranged on the screen. Since windscreen 2 is moist, inner layer 4 can be easily positioned. When inner layer 4 is situated in the desired end position, the moisture can be removed from under the inner layer 4 by wiping using for instance a spatula, in order to prevent air bubbles and to adhere inner layer 4 permanently to windscreen 2. The liquid still present on windscreen 2 can then be removed. Outer layer 5 will then be applied when windscreen 2 is dry. This application takes place by spraying, misting, dripping or rolling a substantially liquid film onto inner layer 4 and optionally partially onto windscreen 2. This liquid film can then be cured, whereby an outer layer 5 is obtained in solid state.

The whole can be polished in order to obtain a smooth, uniform transition between the protective assembly 3 and windscreen 2.

Although they show preferred embodiments of the invention, the above described embodiments are only intended for the purpose of illustrating the invention and not to limit the scope of the invention in any way. The scope of the invention is therefore defined solely by the following claims .

Claims

1. Assembly for protecting a windscreen against damage, the assembly comprising: an inner layer of a first material arranged on the windscreen; and an outer layer of a second material arranged at least partly and preferably wholly on the inner layer, wherein: - the inner and outer layer together distribute and absorb impact energy.

2. Assembly as claimed in claim 1, wherein: the outer layer substantially distributes the impact energy; and the inner layer substantially absorbs the impact energy distributed by the outer layer.

3. Assembly as claimed in claim 1 or 2, wherein the properties of the inner layer are modified for an improved impact energy absorption.

4. Assembly as claimed in any of the claims 1-3, wherein the inner layer is substantially transparent.

5. Assembly as claimed in any of the claims 1-4, wherein the inner layer comprises a UV-resistant material such as silicones with additives optionally incorporated therein.

6. Assembly as claimed in any of the claims 1-5, wherein the inner layer has a thickness in the order of magnitude of 0-5 mm, preferably about 0-2 mm, and more preferably substantially 0-1.5 mm.

7. Assembly as claimed in any of the foregoing claims, wherein the outer layer protects the inner layer substantially against ambient influences.

8. Assembly as claimed in any of the claims 1-7, wherein the outer layer comprises a material having a hardness in the order of magnitude of that of glass, such as polycarbonate .

9. Assembly as claimed in any of the claims 1-8, wherein the outer layer is substantially transparent and/or manufactured from a UV-resistant material.

10. Assembly as claimed in any of the claims 1-9, wherein the outer layer is substantially preformed.

11. Method for arranging a protective assembly on a windscreen, the method comprising of: preparing a windscreen; arranging an inner layer of a first material on the prepared windscreen; and ~ arranging an outer layer of a second material over at least a part of the inner layer.

12. Method as claimed in claim 11, wherein the preparation of the windscreen comprises at least cleaning thereof.

13. Method as claimed in claim 11 or 12, wherein the arranging of the inner layer comprises of: moistening the windscreen; positioning the inner layer on the moistened windscreen; and removing liquid from the windscreen.

14. Method as claimed in any of the claims 11-13, wherein the arranging of the outer layer comprises of arranging a substantially preformed outer layer.

15. Method as claimed in any of the claims 11-13, wherein the arranging of the outer layer comprises of: applying a film in substantially liquid state to the inner layer; and curing the applied film.

16. Method as claimed in any of the claims 11-15, wherein the outer layer is polished in order to obtain a substantially smooth transition between the protective assembly and the windscreen.

17. Method as claimed in any of the claims 11-16, wherein a template is further applied for arranging the inner and/or outer layer.

18. Method as claimed in any of the claims 11-17, wherein the inner layer is a polymer foil, preferably comprising silicones .

19. Method as claimed in any of the claims 11-18, wherein the inner layer is attached to the windscreen.

20. Method as claimed in any of the claims 11-19, wherein the outer layer is applied in substantially liquid state, preferably by means of spraying, atomizing, dripping, dipping or rolling.

21. Windscreen provided with an assembly as claimed in any of the claims 1-10, and/or protected by means of a method as claimed in any of the claims 11-20.

22. Windscreen as claimed in claim 21, wherein the thickness of the inner layer decreases in upward direction along the windscreen.

23. Windscreen as claimed in claim 21 or 22, wherein the inner layer extends from the lower side of the windscreen in upward direction over a distance such that the lower part of the windscreen exposed to chippings is covered.

24. Windscreen as claimed in any of the claims 21-23, wherein the thickness of the inner layer decreases in the direction of the centre (C) of the windscreen.