GB2221832A

GB2221832A - Wiper blade

Info

Publication number: GB2221832A
Application number: GB8918044A
Authority: GB
Inventors: Kurt Bauer; Wolfgang Scholl
Original assignee: SWF Auto Electric GmbH
Current assignee: SWF Auto Electric GmbH
Priority date: 1988-08-17
Filing date: 1989-08-07
Publication date: 1990-02-21
Also published as: IT1231004B; GB8918044D0; DE3827869A1; FR2635495A1; JPH02124348A; IT8921330A0; BR8903473A; ES2016725A6

Description

K.Bauer-W-Scholl 217-44 1 nn 1 S72 2 41 %i WIPER BLADE This invention

relates to wiper blades and more especially to wiper blades for windscreen wiper systems of motor vehicles.

Wiper blades f or modern motor vehicles comprising a shaped (e.g. curved) windscreen comprise a rubber element made of elastic material mounted on a carrier yoke system with several clawed yokes in such a way that the rubber elastic material can easily adapt itself to the curvature of the windscreen. The rubber has a main body to which the actual wiper lip is integrally attached via a web that can be flexed. Elongated grooves for receiving one flexible strip each are provided in the body on both sides, these elongated grooves being needed for stiffening the rubber and for spreading the pressure. The holding claws of the clawed yokes grip the body of the blade rubber, whereby the bent holding webs of these holding claws engage with an additional guide groove of the body. Thus the inner surface of the wall of these holding claws covers the lateral opening of the elongated groove for the flexible strip. Since the wiper lip or the blade rubber of such a wiper blade moves in relation to the carrier yoke system when moving over shaped windscreens and since movement of the flexible strip in its assigned elongated groove cannot be excluded, sufficient play has to be provided for when dimensioning these components. On the other hand it cannot be avoided that the flexible strip and the inner wall of the 1 2 clawed yoke touch each other. If this flexible strip and the clawed yoke are both made of a metallic material, noise will be produced at the points the two parts touch each other, and such noise may be disturbing to the driver of the motor vehicle. The noise could be avoided, if one of the two parts were made of a non-metallic material, especially of plastics. However, for reasons of stability of the wiper blade such a solution cannot always be implemented. The noise produced between the flexible strip and the clawed yoke could also be avoided by embedding the flexible strip into an elongated groove in the basic blade rubber body, which groove is closed or at least partly closed at the side to provide an elongate slot. However, there are some difficulties in manufacturing such a blade rubber -body profile and assembling the flexible strip in a long closed channel or slot is not easy.

An object of the present invention is to provide a wiper blade of the previously mentioned kind by which excessive noise is avoided by using simple means without complicating the assembly of the wiper blade materially in comparison with the prior art.

According to the present invention there is provided a wiper blade, especially for use in windscreen wiper systems of motor vehicles, comprising a blade rubber with a main body and a wiper lip, in which the body comprises at least one elongated groove which is laterally open for inserting a flexible strip from the side, in which a carrier yoke system is provided with at least one clawed yoke with a holding claw partly gripping the main body of the blade -rubber by covering the lateral opening of the elongated groove by means of an inner wall surface, characterised in that the flexible strip is elastically pushed against the inner side wall of the holding claw by resilient elements.

The present invention is based on the idea that noises between two component parts are avoided when these two parts are resiliently pushed against each other by a sufficiently big force. Therefore, as to a wiper blade according to the X 3 present invention resilient elements pushing the flexible strips laterally outwards against the inner side wall of the holding claw are provided. of course, the force exerted by these resilient elements should not be so big that a relative motion between the holding claw and the flexible strip is excluded because in that case the wiper blade could no longer adapt itself to a shaped windscreen to the extent required. Thus as to the realisation of the basic idea of the present invention the form and dimensions of these resilient elements are of special importance.

The depth of the elongated groove for the flexible strip could be smaller than the width of the flexible strip so that the flexible strip projects out of the elongated groove along its entire length and against the side wall of the holding claw. As to such an embodiment, however, it is especially difficult to gauge the elastic pushing force exerted between the flexible strip and the holding claw since the material qualities of the rubber, especially the elasticity of the rubber, cannot be kept constant in a sufficiently precise way. In order to avoid these problems several projections arranged at a certain distance of each other and regionally reducing the depth of the elongated groove are provided as the resilient elements. Thus it is relatively easy to define the pushing force between the flexible strip and the holding claw by means of the height of the projections as well as by the cross-section of these projections.

Theoretically speaking. such projections could of course be inserted into the respective elongated groove of the rubber as separate elements. However. these projections and the rubber blade are preferably manufactured integrally. This can be done without any difficulties if the rubbers are compression moulded.

An easy shift or movement of the flexible strip in the elongated groove is ensured by the fact that the projections touch the front side of the flexible strip only in the form of points or of short lines. This is achieved in an 4 especially simple manner by using projections with a triangular cross- section,- the top of which projections touch the front side of the flexible strip.

The projections could be arranged just at those points of the rubber where the holding claws of the claw yoke act. However, an embodiment is preferred in which the projections are spread along the elongated groove in such a way that each of them is laterally located at a distance from the claws. Whereby changing the distance between such a projection and a claw varies the pushing force between the flexible strip and the holding claw.

It is usual for wiper blades to be provided with elongated grooves on respective sides of the basic body whereby each elongated groove receives a flexible strip. As to such embodiments the projections will be equally distributed on both sides of the web separating the elongated grooves. Thus the projections oppose each other at right angles to the longitudinal direction of the wiper blade so that the flexible strips are pushed laterally outwards against the side walls of the holding claws by an equal distribution of the force. Thus unequal forces exerted on the claws of a carrier yoke system can be avoided.

By way of example the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a side view of half of a wiper blade according to the invention; Figure 2 is a cross-section of a blade rubber of the wiper blade of Figure 1 taken in the area of a holding claw of a clawed yoke; Figure 3 is a partial section of a blade rubber taken along the line III in Figure 2; and, Figure 4 is a partial section of a flexible strip embodied in the wiper blade of Figure 1.

Referring to Figures 1 to 3 of the drawings a windscreen wiper for a windscreen wiper system for motor 1 1 vehicles is designated at 10 and comprises a wiper arm 11 on which a wiper blade 12 is mounted to swivel Figure 1 only shows one half of this wiper blade 12. This wiper blade 12 has associated with it a carrier yoke system 13 consisting in the illustrated embodiment of a main yoke 14, an intermediate yoke 15 mounted to swivel on the main yoke and a clawed yoke 16 mounted to swivel on the intermediate yoke. The clawed yoke 16 has two claws 17 and the intermediate yoke has a claw 17 f or guiding a blade rubber 18. This blade rubber 18, as illustrated in Figure 2, has a known prof ile or cross-section. It consists of a main body 20 with a cross-section in the general shape of a trapezoid in which elongated grooves 21 are provided on both sides. Furthermore guide grooves 22 are provided on both sides of the body 20. A narrow web 24 that can be f lexed extends from a base part 23 and connects wiper lip 25 with the body 20.

Figure 2 shows one of the holding claws 17. The claw comprises a web 30, two side walls 31 projecting laterally from the web and holding lugs or webs 32 extending inwards from the side walls. The web 30, the side walls 31 and the inturned holding webs or lugs (32) bound an area corresponding incompletely to the cross-section of the blade rubber body 20, whereby the inturned holding webs 32 engage the guide grooves 22 of the body. Thus the holding claws 17 partly grip the blade rubber body 20. Thereby the inner surfaces 35 of the holding claw 17 cover the lateral openings 26 of the elongated grooves 21.

Figure 3 shows a longitudinal cross-section of the blade rubber 18 in the region of the elongated grooves 21 provided for receiving a flexible strip 40. The elongated grooves 21 are closed at 27 at the one end of the wiper blade. Projecting studs 28 are provided at a distance from the closed end of the grooves 21 and these studs engage respective recesses 41 of the appertaining flexible strips 40. Thus, at the one end of the blade rubber 18 the position of the flexible strip 40 in relation to the rubber 6 18 is secured.

Wiper blades comprising the features so far described with reference to the drawings have hitherto been manufactured in a large number of pieces. According to the invention resilient elements in the form of projections 50 are provided which act on a front side 42 of the f lexible strip 40 and laterally push the flexible strip against the inner wall surface 35 of the holding claws 17. The crosssection of the projections 50 - in the plane of the flexible strips 40 - is triangular, whereby the top 51 of each projection touches the front side 42 of the flexible strip 40. Thus the top 51 of each projection 50 and the front side 42 of the flexible strip are touching each other along a line. So the necessary relative motion between the flexible strip and the rubber is provided. The projections 50 and the blade rubber 17 are manufactured integrally and project from the base 60 of the elongated groove 21. Their length corresponds to the width of groove B, i.e. they extend the total width of the groove 21 to the side walls 61 and 62 of the groove 21. In Figure 1 the way these projections 50 are positioned or spread along the elongated groove 21 is indicated by means of arrows P. This shows that these projections 50 are spread along the elongated groove 21 in such a way that each of them is laterally positioned at a distance corresponding to the spacing of the claws 17 of the clawed yoke. Finally, Figure 3 also makes clear that as to the usual rubbers comprising two elongated grooves formed in the basic body, whereby each elongated groove receives a flexible strip, the projections 50 are located on both sides of the web 65 separating these elongated grooves. Thus the projections are equally spread in both elongated grooves.

Figure 2 illustrates a cross-sectional view of a rubber in which a flexible strip 40 is inserted only into the righthand elongated groove 21. Comparing the width of the projection 50 in the righhand elongated groove 21 with the width of the projection 50 in the left hand elongated groove zb 7 21 it can be seen that the flexible strip 40 is pushed against the inner wall surface 35 of the holding claw 17 by a certain pushing force. This pushing force is so big that during normal operation rattling noises of the metallic parts touching each other at this point are effectively avoided. On the other hand, however, the pushing force is only so big that the necessary ease of movement of the system in the longitudinal direction of the rubber is not hindered.

A wiper blade of this kind can be manufactured and mounted in the usual way so that no additional costs are incurred by constructing it according to the present invention, but great advantages with respect to noisy behaviour are achieved.

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Claims

CLAIMS:

1. A wiper blade, especially f or use in windscreen wiper systems of motor vehicles, comprising a blade rubber with a main body and a wiper lip, in which the body comprises at least one elongated groove which is laterally open for inserting a flexible strip from the side, in which a carrier yoke system is provided with at least one clawed yoke with a holding claw partly gripping the main body of the blade rubber by Covering the lateral opening of the elongated groove by means of an inner wall surface, characterised in that the flexible strip (40) is elastically pushed against the inner side wall (35) of the holding claw (17) by resilient elements (50).

2. A wiper blade according to claim 1, characterised in that a plurality of projections (50) spaced from each other and reducing the depth of the elongated groove (21) at intervals therealong serve as the resilient elements (50).

3. A wiper blade according to claim 2, characterised in that the projections (50) and the rubber (18) are manufactured integrally.

4. A wiper blade according to claim 3, characterised in that the projections (50) project from the bottom (60) of the elongated groove (21) and extend over the full width of the groove (B) up to the side walls (61,62) of the groove and in that the projections act upon the front side (42) of the flexible strip (40) which faces the bottom (60) of the groove.

5. A wiper blade according to any one of the claims 2 to 4, characterised in that the cross-section of the projections (50) in the plane of the flexible strips (40) is such that the projections touch the front side (42) of the flexible strip (40) as points or as a line.

6. A wiper blade according to claim 5, characterised in that the crosssection of the projections (50) is approximately triangular and that the apex (51) of each projection touches the front side (42) of the flexible strip (40).

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7. A wiper blade according to any one of the claims 2 to 6, characterised in that the projections (50) are spread along the elongated groove (21) in such a way that they are spaced apart by the claws (17) of the clawed yoke (16) of 5 the carrier yoke system (13).

8. A wiper blade according to any one of the claims 2 to 7, characterised in that elongated grooves (21) are provided in the sides of the basic body (20) of the blade rubber (18), that each elongated groove (21) receives a flexible strip (40) and that the projections (50) are equally spread on both sides of the web (65) separating the elongated grooves (21) and of the bottom of the groove (60).

9. A wiper blade substantially as hereinbefore described with reference to the accompanying drawings.

Published 1990 atThe Patent Office. State House.6671 High HolbOrn,, LondonWC1R4TP. Further copies maybe obtainedfrom The Patent =ice. Sales Branch. St Mary Cray. Orpingtor. Kei.t BR5 3F.D. Pr,r:ed by ?A,-;':.jplex techniques Ita, St Mary Cray, Kent. Con. 1W