wiper rubber profile

Abstract

Wiper rubber profile comprising a head part (12) for mechanically fixing the wiper rubber profile (10) to a wiper blade of a windshield wiper, further comprising a wiper lip (14) for cleaning a corresponding surface, in particular a motor vehicle windshield, and a tilting bridge (16) which connects the head part (12) to the wiper lip (14), in particular movably, characterized in that the wiper rubber profile (10) has at least a surface layer of a polymer that swells upon contact with water, wherein the wiper rubber profile (10) has a surface layer of a first layer (20, 20a) of a polymer with an optical appearance that differs from that of the surrounding wiper rubber surface, and a second layer (22, 22a) of the water-swellable polymer which at least partially or completely covers the first layer (20, 20a).

Description

State of the art

[0001] The present invention relates to a wiper rubber profile, a method for operating the same and its use according to the preamble of the independent claims.

[0002] It is well known that windshield wiper blades wear out over time, to a greater or lesser degree. This wear is caused by various environmental factors, such as exposure to UV light, temperature fluctuations, and the presence of dirt or ice on the windshield. Because this type of wear is a very slow process, it often goes unnoticed by drivers.

[0003] In this regard, it is known from DE 102 35 566 A1 to equip the wiper blade's wiping strip with a wear indicator. This can be of an electronic, mechanical, or chemical nature.

[0004] From JP S63 47 969 U, a wiper rubber profile is known, comprising a head part for mechanically fixing the wiper rubber profile to a wiper blade of a windshield wiper, further comprising a wiper lip for cleaning a corresponding surface, in particular a motor vehicle windshield, as well as a tilting bridge which connects the head part with the wiper lip in a movably manner.

[0005] From JP 2003-253 214 A, a thermosetting or vulcanizable resin material or an elastomer material is known which has a silicone oil composition containing a silicone oil, wherein the coating composition contains a layered lattice structure material.

[0006] From JP 2004-338 529 A, a wiper rubber profile is known which has on its surface a first layer of a polymer with an optical appearance changed compared to the surrounding wiper rubber surface, as well as a second layer which covers the first layer at least partially, in particular completely.

[0007] From DE 10 2009 000 320 A1, a wiper blade comprising an elastomer profile, a base layer which at least partially covers the surface of the elastomer profile and comprises at least one particulate lubricant, and a water-soluble and / or water-dispersible top layer covering a base layer, as well as a manufacturing process for producing such a wiper blade is known. Advantages of the invention

[0008] According to the invention, a wiper rubber profile, a method for operating the same and its use with the characterizing features of the independent patent claims are provided.

[0009] This is based on the fact that a wiper rubber profile comprises a head part, which serves for the mechanical fixing of the wiper rubber profile to a wiping device such as a wiper blade of a motor vehicle, and a wiping lip, which is designed to clean a surface to be cleaned, such as a windshield of a motor vehicle, and which are movably connected to each other by means of a hinge, for example. According to the invention, the wiper rubber profile comprises at least in a surface area a polymer which exhibits an increase in volume upon contact with water.

[0010] The advantage of this measure lies in the fact that, due to the volume increase of the water-swellable polymer when exposed to moisture and the subsequent volume decrease upon drying, the contour of the wiper profile made from this polymer changes. After numerous swelling cycles, comprising an initial volume increase and subsequent volume contraction upon drying, a sufficiently large and permanent contour change occurs. This change alters the visual appearance of the wiper profile in such a way that it is noticeable to a user, indicating wear and tear.

[0011] Further advantageous embodiments of the present invention are the subject of the dependent claims.

[0012] It is therefore advantageous if the polymer, which swells upon contact with water, covers an area, in particular a layer, of the wiper rubber profile, e.g., completely or at least partially, whereby the area or layer of the wiper rubber profile has a different optical appearance compared to a surrounding surface of the wiper rubber profile.

[0013] In this way, the polymer that swells under water contact, together with the area comprising a material exhibiting a changed optical appearance, forms a wear indicator, since with continuous wear, based on a multitude of swell cycles of the polymer that swells under water contact, areas of the material with a changed optical appearance become visible to an observer, which are not optically accessible to an observer in the factory-new state of the wiper rubber profile.

[0014] From this changing optical appearance of the wiper rubber profile in the area of ​​the polymer that swells under water contact or of the material with a changed optical appearance, conclusions can be drawn about the degree of wear of the underlying wiper rubber profile.

[0015] According to a further advantageous embodiment, the polymer capable of swelling upon contact with water is, for example, a derivative of an acrylic acid, in particular an acrylamide or a methacrylate. This can be, for example, poly(N-isopropylacrylamide) or diethylene glycol methacrylate. Furthermore, mixtures of a polyacrylate with a polyacrylamide are suitable. In addition, star-shaped polyethylene glycols, in particular, exhibit suitable swelling behavior upon contact with water. They can therefore be used individually or in mixtures with one another.

[0016] Furthermore, the water-swellable polymer can additionally contain, for example, a hygroscopic filler such as particles of hygroscopic glass. This leads to a further increase in volume of the water-swellable polymer and thus to an enhancement of the volume expansion effect.

[0017] According to a particularly preferred embodiment of the present invention, the wiper rubber profile has on its surface a first layer of a polymer with an optical appearance that differs from that of the surrounding wiper rubber surface, and on the first layer a second layer of a polymer that swells upon contact with water, wherein the second layer covers the first layer at least partially, but in particular completely.

[0018] In this way, the corresponding wiper rubber profile conveys a superficially uniform optical impression in a brand-new state, which subsequently changes in use due to a multitude of swelling and drying cycles of the water-sensitive polymer, in that increasingly areas of the first layer become optically accessible to the viewer, which were initially not optically accessible to the viewer due to being covered by the second layer.

[0019] If the first or second layer is applied, for example, to a side area of ​​the wiper blade lip or the tilting bridge, the change in the visual appearance of the wiper blade profile during use can be recognized particularly easily.

[0020] Applying the first and second layers to the lateral boundary surfaces of the tilting ridge is particularly advantageous, as these surfaces are naturally subjected to considerable mechanical stress during use when the wiping rubber lip folds over during cleaning. This helps to support the contour changes of the second layer after a certain number of swelling and drying cycles. This can be due, for example, to partial detachment of the second layer from the surface of the wiping rubber profile.

[0021] Another advantageous embodiment of the present invention provides that the polymer, with its altered optical appearance compared to the surrounding wiper rubber surface, contains a color pigment or a UV indicator or an IR indicator. In the former case, the observer can recognize, without further technical aids, that the optical appearance of the wiper rubber profile has changed in such a way that wear of the wiper rubber profile can be assumed.

[0022] In the second case, a suitable UV or IR source is required to detect a change in the optical appearance of the wiper blade profile caused by the polymer with the altered optical appearance. Although this represents an increased detection effort, the advantage lies in the fact that in daily use, the user of the wiper blade profile is not constantly reminded that the wiper blade profile is likely subject to increased wear. Brief description of the drawings

[0023] Exemplary embodiments of the present invention are shown in the drawing and explained in more detail in the following description. It shows: Fig. 1 the schematic representation of a wiper rubber profile according to a first embodiment of the present invention, Fig. 2 the schematic representation of a wiper rubber profile according to a second embodiment of the present invention and Fig. 3 the schematic representation of a wiper rubber profile according to a third embodiment of the present invention.

[0024] In Fig. Figure 1 is a schematic representation of a wiper rubber profile according to a first embodiment of the present invention. The wiper rubber profile 10 comprises a head section 12, which, for example, serves to hold the wiper rubber profile on a wiper blade of a motor vehicle wiper. Furthermore, the wiper rubber profile 10 comprises a lip section 14, the interface of which, facing away from the head section 12, comes into contact with a surface to be cleaned, for example, a window of a motor vehicle, during operation. The head section 12 and the lip section 14 are flexibly connected to each other, for example, by a hinge 16. Preferably, both the head section 12 and the lip section 14 are made of a suitable elastomeric material.

[0025] The head section 12 can be made of the same elastomeric material as the tilting bridge 16 or the lip section 14. Alternatively, different elastomeric materials can be selected, adapted to the respective property profile of the different components of the wiper rubber profile 10. Suitable elastomeric materials include, for example, ethylene propylene terpolymers, natural rubber, chloroprene rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile butadiene rubber, polyurethane elastomers, mixtures of acrylonitrile butadiene rubber and polyvinyl chloride, or mixtures of the aforementioned materials.

[0026] Since the interface of the wiper rubber profile 10 facing the surface to be cleaned is constantly exposed to abrasive forces, the wiper rubber profile 10 experiences continuous wear after a certain period of use. To make this wear visible in a timely manner, the wiper rubber profile 10 has a wear indicator 18. The wear indicator 18 comprises, for example, a first layer 20, which contains a polymeric material that has a visually different appearance compared to the surface of the wiper rubber profile 10 surrounding the wear indicator.

[0027] The polymeric material of the first layer 20 can, for example, contain one or more color pigments and / or UV or IR indicators. The former enable the observer to perceive a change in the color appearance of the wiper rubber profile in the area of ​​the wear indicator 18 without any further technical aids.

[0028] If the first layer 20 contains a UV or IR indicator, a color change in the wiper rubber profile can only be detected with the aid of a suitable spectroscopic detection device. On the other hand, this embodiment has the advantage that the wear indicator 18, which indicates the need for replacement, is not constantly visible when viewing the wiper rubber profile 10.

[0029] The first layer 20 is preferably completely covered with a second layer 22, which contains a polymer that exhibits an increase in volume upon contact with moisture or water. This water-swellable polymer causes an increase in the volume of layer 22 upon contact with water, and thus a change in the contour of the second layer 22. During a subsequent drying process, the water-swellable polymer shrinks or decreases in volume, resulting in a further change in the contour of the second layer 22. A water-swellable polymer is defined as a polymer that exhibits a volume increase of, for example, at least 2 vol.%, preferably at least 5 vol.%, and particularly at least 10 vol.% upon contact with water or moisture.

[0030] If such volume expansion and contraction cycles are repeated, the contour of the second layer 22 undergoes a permanent change over time compared to its initial state. This permanent contour change 22 allows the first layer 20 to be partially exposed, making it visible to an observer in the vicinity of the wiper blade profile 10. Since its optical appearance differs from that of the surrounding area of ​​the wiper blade profile 10, an observer can easily detect wear on the wiper blade profile 10 and replace it, possibly with the aid of technical devices as described above.

[0031] It is assumed that contact with moisture of the second layer 22 typically occurs when the vehicle is used in bad weather with a wiper blade containing the wiper rubber profile 10. Therefore, the number of volume expansion and contraction cycles of the second layer 22 is a direct measure of the number of operating hours of the wiper blade in wet weather. In this way, it can be assumed that the detection of the first layer 20 being exposed to the surroundings of the wiper rubber profile 10 is equivalent to wear of the wiper rubber profile 10.

[0032] In an alternative embodiment, which is also in Fig. As shown in Figure 1, the wear indicator 18 is not integrated into the material of the wiper lip section 14, but is raised on it. This allows for particularly simple manufacturing of the wear indicator 18. In this case, an alternative first layer 20a is raised on the wiper lip section 14 and, in particular, is also completely covered with a second layer 22a. The alternative first layer 20a, like the first layer 20, comprises a polymeric material that provides a different optical appearance from the surrounding material, and the alternative second layer 22a comprises a polymer that exhibits an increase in volume upon contact with moisture.

[0033] Suitable polymeric materials for the second layer 22 or the alternative second layer 22a include, for example, acrylic acid derivatives such as acrylamides or methacrylates. The use of poly(N-isopropylacrylamide) or diethylene glycol methacrylate, as well as mixtures of polyacrylates with polyacrylamides, is particularly suitable. Alternatively, the use of star-shaped polyethylene glycols is also conceivable. A mixture of the aforementioned materials is also possible. The volume expansion effect of the polymeric material of the second layer 22 or the alternative second layer 22a can be further enhanced by the addition of, for example, hygroscopic fillers. Hygroscopic glass particles or sands are suitable examples.

[0034] In Fig. Figure 2 shows a wiper rubber profile according to a second embodiment of the present invention. Furthermore, the same reference numerals denote the same component parts as in [reference 2]. Fig. 1.

[0035] The wiper rubber profile 10 includes a wear indicator 18 in the form of a longitudinal strip 24 extending the entire length of the wiper rubber profile 10. The wear indicator 18 can be provided, for example, on both sides of the wiper lip section 14 or only on one side, preferably on an underside of the wiper rubber profile 10, if the latter is mounted inside a wiper blade and is in a resting state, e.g., on a motor vehicle.

[0036] In this way, the wear indicator 18 is not visible during the wiper blade's rest state, but becomes noticeable to the driver during operation of the wiper blade because the underside of the wiper blade or the wiper rubber profile 10 is then also in his field of vision.

[0037] A wiper rubber profile 10 according to a third embodiment of the present invention is in Fig. 3 shown. The same reference symbols also denote the same component components as in the Fig. 1 and Fig. 2.

[0038] At the in Fig. In the exemplary embodiment of a wiper rubber profile 10 shown in Figure 3, the wear indicator 18 is provided, for example, in the form of a round surface segment, for example, in the area of ​​the tilting web 16. It is possible to apply multiple wear indicators 18 to the wiper rubber profile 10, thus creating a continuous series of wear indicators 18 on the side surfaces of the tilting web 16. It is understood that the aforementioned embodiments of the wear indicator 18 are derived from the Fig. 1, Fig. 2 and Fig. 3 are combinable or interchangeable in their embodiment or with regard to their application location.

[0039] The present invention also relates to a method for operating such a wiper rubber profile or a windscreen wiper containing it.

[0040] In this process, electromagnetic radiation emanating from a wiper rubber profile surface, such as visible light or UV or IR radiation, is detected in a first step, in particular that emitted by a polymer positioned on the wiper rubber profile surface with altered optical properties compared to those of a surrounding wiper rubber surface.

[0041] In a second step, if a corresponding electromagnetic radiation emanating from the polymer with altered optical properties positioned on the wiper rubber profile surface is detected, or if a modified wiper rubber surface is photographically detected, a conclusion is drawn that the wiper rubber profile is worn, and in a third step, the replacement of the wiper rubber profile is initiated.

[0042] The wiper rubber profile 10 according to the invention is used, for example, in wiper blades for windscreen wipers of motor vehicles, rail vehicles or aircraft, as well as in cleaning devices, for example, for cleaning glazing on buildings.

Claims

[1] Wiper rubber profile comprising a head part (12) for mechanically fixing the wiper rubber profile (10) to a wiper blade of a windshield wiper, further comprising a wiper lip (14) for cleaning a corresponding surface, in particular a motor vehicle windshield, and a tilting bridge (16) which connects the head part (12) to the wiper lip (14), in particular movably, characterized by , that the wiper rubber profile (10) has at least a surface layer of a polymer that swells when in contact with water, wherein the wiper rubber profile (10) has a surface layer of a first layer (20, 20a) of a polymer with an optical appearance that differs from that of the surrounding wiper rubber surface, and a second layer (22, 22a) of the water-swellable polymer which at least partially or completely covers the first layer (20, 20a). [2] Wiper rubber profile according to claim 1, characterized by, that the polymer which swells under contact with water covers an area (20, 20a) of the wiper rubber profile (10) in particular completely, which has an optically altered perception compared with a surrounding surface of the wiper rubber profile (10). [3] Wiper rubber profile according to claim 1 or 2, characterized by that the polymer, which swells upon contact with water, is a derivative of an acrylic acid, in particular an acrylamide or a methacrylate. [4] Wiper rubber profile according to claim 3, characterized by that the water-contact swellable polymer is a poly(N-isopropylacrylamide), a diethylene glycol methacrylate, or a mixture of a polyacrylate with a polyacrylamide. [5] Wiper rubber profile according to one of the preceding claims, characterized by that the polymer which swells upon contact with water is a particularly star-shaped polyethylene glycol. [6] Wiper rubber profile according to one of the preceding claims, characterized by that the polymer, which swells upon contact with water, additionally contains a hygroscopic filler, in particular particles of a hygroscopic glass. [7] Wiper rubber profile according to one of the preceding claims, characterized by , that the polymer which swells upon contact with water is provided in a lateral area of ​​the wiper rubber lip (14) or in a lateral area of ​​the tilting bridge (16). [8] Wiper rubber profile according to one of the preceding claims, characterized by that the polymer with an altered optical appearance contains a color pigment, a UV indicator or an IR indicator. [9] Method for operating a wiper rubber profile according to any of the preceding claims, characterized by, that in a first step electromagnetic radiation emanating from a wiper rubber profile surface is detected, in particular that from a polymer positioned on the wiper rubber profile surface with a changed optical impression compared to that of the surrounding wiper rubber surface, and that in a second step upon detection of a corresponding electromagnetic radiation or upon photographic detection of a changed wiper rubber surface, a conclusion is drawn that the wiper rubber profile (10) is worn, and in a third step the replacement of the wiper rubber profile (10) is initiated. [10] Use of a wiper rubber profile according to one of claims 1 to 8 or of a method according to claim 10 in windshield wipers of motor vehicles, rail vehicles or aircraft as well as in cleaning devices for window glass panes.

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