Windscreen wiper with a driven wiper arm and wiper blade jointed thereto for cleaning screen in particular on motor vehicles

Wiper lever (10) with a driven wiper arm (12) and a wiper blade (16) linked to it for cleaning windows, particularly those of motor vehicles, which is provided with a band-like, long-stretched-out, elastic supporting element (30), which features, on its lower band surface facing the window, a long-stretched-out, rubber elastic wiper strip (24) that can be applied to it, on whose upper band surface (29), particularly in the longitudinal middle area of the supporting element (30), a coupling part (32) is situated and wind deflector strip partial sections (52) extending to the ends of the supporting element are arranged on both sides of the coupling part (32). An especially harmonic transition between the wiper blade (16) and the wiper arm (12) is achieved in the area of the joint (46, 47) connecting these two wiper lever parts if the wiper lever (10) is provided with a cap (60) to cover the connection area between the wiper blade (16) and the wiper arm (12).

STATE OF THE ART

In the case of a wiper lever of the type designated in the pre-characterizing clause of the independent claim, the supporting element of the wiper blade is supposed to guarantee, over the entire wiper field being covered by the wiper blade, the most uniform possible distribution of wiper blade application force on the window originating from the wiper arm. Due to the corresponding curvature of the relaxed supporting element—i.e., when the wiper blade is not adjacent to the window—the ends of the wiper strip that are placed completely against the window during wiper blade operation are loaded by the supporting element that is stressed vis-à-vis the window, even when the radii of curvature of spherically curved vehicle windows change with every wiper blade position. As a result, the curvature of the wiper blade must be somewhat greater than the greatest curvature measured in the wiper field on the to-be-wiped window. The supporting element thereby replaces the expensive supporting bracket design that is required to distribute the application force and that has two spring rails, which are arranged in the wiper strip and are used for transverse reinforcement of the rubber elastic wiper strip, as is the practice with conventional wiper blades (DE-PS 1247 16 1).

In the case of a known wiper lever with a wiper blade where, for reasons related to bearing pressure distribution, the supporting element projects in the wiper blade middle range far beyond the width of the wiper strip (DE-PS 1247161), the front side facing the air stream can be affected by the build-up of excess pressure. On the other hand, a considerable negative pressure builds up on the rear side facing away from the air stream due to the abovementioned wiper blade structure. In operation, though the wiper blade executing a pendulum motion constantly changes its position relative to the inflowing air stream, its one longitudinal side does indeed continually face this stream more or less strongly and is therefore designated as the front side while its other longitudinal side consequently is also viewed as the rear side. In the combined action of these two previously mentioned pressures, both of which are acting in the opposite direction of the wiper blade application force, they are at least reduced at higher travel speeds so that a proper wiper result is no longer possible. In order to remedy this unfavorable flow behavior, in the case of a known wiper lever in accordance with the species (DE 198 56299.3 A1), a wind deflector strip with a flow surface facing one of the main flow directions is arranged on the upper band surface of the supporting element. This wind deflector strip has two sections or partial strips each of which extends from the connecting device to the ends of the supporting element or the wiper blade. As a result, this produces a free space in the progression of the wind deflector strip for positioning the connecting device. Manufacturers of luxury class vehicles in particular object to this optical interruption of the wind deflector strip for reasons related to styling. In addition, this interruption of the flow surface on the wind deflector strip contributes to an undesirable increase in air stream noise due to the edges and gaps that are thereby produced.

It is true that adapting the cross-section of a holder situated in the longitudinal middle area of the wiper blade on its upper band surface for two spring rails belonging to the supporting element to the cross-section of the wind deflector strip sections extending on both sides of the holder is known in the case of the wiper lever according to the species, but the means to connect the wiper blade to the wiper arm are also completely free in this case so that this wiper lever, including a wiper arm and wiper blade, is also encumbered with the already described disadvantages.

ADVANTAGES OF THE INVENTION

Due to the arrangement of the cap in the connection area between the wiper arm and the wiper blade, an elegant transition between the two wind deflector strip sections adjacent to the connecting device can be achieved via an appropriate formation of the cap. In doing so, it is possible to adapt at least the cap sections, which can also cover the areas of these sections that are adjacent to them, to the shape of the wind deflector strip. Moreover, problem zones on the wiper lever that oppose a laminar flow of the air stream and generate air stream noise are thereby avoided. Finally, the cap protects the sensitive articulated connection between the wiper arm and the wiper blade against environmental influences such as dirt from the road, snow, ice, etc.

A particularly simple adaptation of the cap to the embodiment of the wiper blade is possible if the cap is supported by the wiper blade, in particular if it is locked to the wiper blade.

This can be achieved in a cost-effective manner by the cap that is U-shaped in cross-section being fabricated of an elastic plastic and being provided with elastically deflectable locking means, which are assigned to counter-locking means of the wiper blade.

If the wiper blade's counter-locking means are embodied on the outer longitudinal edges of the band-like supporting element, no special measures are required to embody the counter-locking means.

In order to obtain a stable, locking connection that can handle the pressure of the inflowing air stream, the cap is provided with at least one support cooperating with the upper band surface of the supporting element, whereby elastically deflectable locking noses that grip under the supporting element and serve as locking means are formed on the cap.

With respect to the flexibility of the wiper blade or the supporting element it can be particularly advantageous if, in the area of the holding claws of the coupling part serving as a connecting piece, the cap is provided, on its elastically deflectable inside wall, with clamp-like safety claws that grip over the holding claws.

Simple assembly of the wiper lever is produced if the cap is provided with a passage opening for the wiper arm.

Because the wind deflector strip material ages over the course of time, something that goes hand in hand with a certain shrinkage, an air gap can form between the cap and the front sides of the wind deflector strip partial sections that face it, which can lead to the already described disadvantages regarding the optical effect and the intensification of noise. This can be avoided in accordance with a development of the invention with extensions on the cap that cover the end areas of the wind deflector strip partial sections that face them.

For optical reasons and for reasons related to the undesired generation of air stream noise, it can be advantageous if the cap is provided with a flute on its one longitudinal wall in continuation of the flow fluting of the wind deflector strip.

For certain application cases, it can be favorable if the cap is supported by the wiper arm.

Due to a pivoted arrangement of the cap on the wiper arm, the cap always remains connected to the wiper arm and present. It can be moved between two positions: the operating position and release position.

In order to secure the cap in its operating position, the wiper arm is provided with rest receptacles that align with one another on opposite longitudinal walls, which are assigned pivot pins arranged on the cap walls adjacent to the longitudinal walls.

A simple, suitable pivot arrangement is achieved for the cap if the cap is manufactured of an elastic plastic and the pivot pins are arranged on elastically deflectable wall areas of the cap.

In order to secure the cap in its operating position, locking means are formed on the elastically deflectable wall areas of the cap, which cooperate in the cap's operating position with counter-locking means on the wiper arm.

In the case of a wiper lever in which the connection between the wiper arm and the wiper blade is accomplished via a sliding movement, whereby a stop shoulder of the wiper arm fixes the operating position with a counter-shoulder of the wiper blade, an unintentional release movement of the wiper blade from the wiper arm is safely avoided if a safety nose facing the wiper blade is arranged on the cap, which nose engages in this operating position and in the cap's operating position so that it fits in a safety recess on the wiper blade.

Additional advantageous further developments and designs of the invention are disclosed in the following description of the exemplary embodiments depicted in the associated drawing.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

A first exemplary embodiment of a wiper lever10according to the invention (FIG. 1) includes a wiper arm12driven on one end and guided on a motor vehicle (not shown here). The driven end of the wiper arm has been assigned reference number11inFIG. 1. A long-stretched-out wiper blade16belonging to the wiper lever10is linked to the other, free end14of the wiper arm. The wiper arm12is positioned on its drive end11in such a way that it can move in a pendulum fashion between reverse positions around a pendulum axis20during wiper operation in a vertical plane on the drawing plane. In doing so, the wiper blade16is moved transverse to its longitudinal extension over the to-be-wiped window, whereby it is adjacent to the surface28of the to-be-wiped window with a rubber elastic wiper strip24. The wiper strip24is connected parallel to its longitudinal axis with a band-like, long-stretched-out, elastic supporting element30, on whose upper band surface29facing away from the window a coupling part32is situated (FIGS. 5 and 7) via which the wiper blade16is connected to the wiper arm12in an articulated manner to form the wiper lever. The wiper strip24is therefore arranged on the lower, window-facing band surface31of the supporting element30. The coupling part32, whose cross-section is T-shaped in sections, faces the supporting element30with its T-head34and grips around the outer longitudinal strips40of the supporting element30that face away from one another with claws38arranged on the T-head. The coupling part32is connected to the supporting element30at these claws, for example welded and/or fixed here to press the claws together. In the case of the embodiment, the supporting element30includes two spring rails42, which extend parallel to one another lying in a common plane. The facing inner longitudinal strips41of the spring rails42lie in the open-edge longitudinal grooves of the wiper strip24.

The T-foot36of the coupling part32extends away from the supporting element30and is penetrated by an articulated bolt46whose two ends project out of the T-foot, as shown inFIGS. 5 and 6. The wiper arm12(indicated with a dash-dotted line inFIGS. 5 and 6) engages at this articulated bolt or at its free ends with correspondingly embodied rest recesses. An adapter48that is preferably fabricated of plastic is located between the T-foot36and the wiper arm12, and this adapter guarantees an operationally reliable connection between wiper arm12and wiper blade16to form the wiper lever10. FIGS.5and6show that the articulated bolt46or its articulation axis47essentially extends in the direction of the pendulum or work movement of the wiper lever10. AsFIG. 1shows, the to-be-wiped surface28of the window is curved. Since the line28is supposed to represent the greatest curvature of the window surface, it is clearly evident that the curvature of the still relaxed wiper blade16that is adjacent to the window surface at its two ends18is greater than the maximum curvature of the window. Under the application force acting in the direction of arrow22(FIG. 1) and exerted by the wiper arm12, the wiper blade applies its rubber elastic wiper strip24arranged on the lower band surface31of supporting element30to the window surface28over its entire length. In doing so, tension builds up in the elastic supporting element30fabricated of metal and this tension is responsible for the proper application of the wiper strip24over its entire length on the window, as well as for a uniform distribution of the application force22. Moreover, the spring rails42of the supporting element30are responsible for the required transverse stabilization of the rubber elastic wiper strip24. Because the normally spherically curved window does not represent a section of a spherical surface, the wiper blade16must be able to constantly adapt to the respective position and progression of the window surface28vis-à-vis the wiper arm12during its wiper operation. For this reason, a smooth-running articulated connection between the wiper arm12and the wiper blade16that enables an oscillation motion around the pivot pin axis47is required. Furthermore,FIG. 1, in connection withFIG. 5, shows that the articulation axis47is also aligned transverse to the direction of the application force (arrow22).FIGS. 1,2and7show that the wiper blade is provided on the upper band surface29of the supporting element30with a wind deflector strip50connected with the wiper strip24for example, and this wind defector strip includes two partial sections52that are at a distance54from one another as seen in the longitudinal direction of the wiper blade (FIG. 7). A free space56in the wind deflector strip50is thereby produced, which facilitates the arrangement of the coupling part32on the supporting element30. The wind deflector strip50is provided with a flow fluting58on its one longitudinal side against which the air stream mainly flows (FIG. 2). In order to cover the articulated connection between the wiper arm10and the wiper blade12or between its coupling part32and to achieve a harmonic transition between the facing ends of the partial sections52of the wind deflector strip50, the wiper lever10also has a cap60whose structure is supposed to be explained on the basis ofFIGS. 3 and 4in particular. The cap has a trough-shaped middle section62, whose trough base is largely removed so that a passage opening64is produced. AsFIG. 3in particular shows, extensions70that project beyond the two transverse end walls66and68are adjacent and their shapes are adapted to the cross-sectional shape of the wind deflector strip50and they also feature a flow fluting59. The two longitudinal walls72of the cap60that is manufactured of an elastic plastic are provided with elastically deflectable locking means, which are embodied as locking noses74in the exemplary embodiment. In this connection, two locking noses74are each arranged at a distance from one another on each longitudinal wall72and the locking noses of the two longitudinal walls72are opposite one another in pairs (FIGS. 3 and 5). In addition, supporting or reinforcing walls76are arranged on each longitudinal wall, in particular between the locking noses74, and the walls extend essentially from the passage opening64until close to the trough edge78of the cap60. The one transverse wall68of the cap60is provided with a channel80, which extends from the passage opening64over a small partial section to the trough edge78and terminates at the end of the extension70. The ends of the supporting rips76facing the trough edge78are recessed matching the width of the supporting element30so that supports82are produced. A flute94is also embodied on the one longitudinal wall72of the cap60in continuation of the flow fluting58of the wind deflector strip50or in continuation of the flow fluting59on the extensions70.

Assembling the cap on the wiper blade shall be explained in the following on the basis ofFIGS. 5 and 7.

As can be seen from the pre-assembly position inFIG. 7, the entire length84of the cap including its extensions70is greater than the distance54between the two partial sections52of the wind deflector strip50. This is caused by the two extensions70. Starting from the pre-assembly position (FIG. 7), the cap60is placed on the wiper blade16in the direction of the arrow86. During the placement movement, the locking nose74deflects in the direction of the arrow90inFIG. 5because of its shape, for example the formation of starting bevels,88, when the starting bevels88hit against the longitudinal strips40of the supporting element30. The deflection can be achieved either via certain cross-sectional modifications to the locking nose that are known to the specialist and/or by an elastic deflection of the longitudinal walls72of the cap60. The assembly movement (arrow86) of the cap is ended when the supports82on the supporting rips76are sitting at the upper band surface29of the supporting element30. In this position the locking noses74can spring back into their initial position, because the outer longitudinal strips40of the supporting element30can reach into the rear sections92of the locking noses74, whereby the locking noses grip under the supporting element30and thereby bring about a secure fit of the cap60onto the wiper blade16. In the operating position of the cap60that is now achieved, the extensions70of the cap each cover the facing end sections of the partial sections52of the wind deflector strip50. Since the shape of the extensions essentially represents a continuation of the contour of the wind deflector strip50, a harmonic transition between the wind deflector strip and the cap is guaranteed. In addition, the middle section62can also be provided with at least a slight flute94in accordance with the respective spatial possibilities so that a cap with a flow-favorable surface is produced, which can contribute to the quiet operation of the wiper lever10.

After the cap has been connected to the wiper blade, further assembly of the wiper lever can take place by the free end14of the wiper arm12being guided through the passage opening64thereby producing the articulated connection. Depending upon the design of the articulated connection, however, it can also be necessary to first stick the wiper arm through the passage opening64of the still loose cap, creating the articulated connection, and then lock the cap on the wiper blade in the described manner.

An alternative possibility for fastening the cap100to the wiper lever10is shown inFIG. 6. In contrast to the embodiment just described in which the locking noses74engage on the supporting element30and therefore must be placed next to the claws38of the coupling part32, the safety claws or holding claws102of the cap100grip around the claws38of the coupling part32. They are therefore placed and formed in such a way that they act upon the wiper blade in accordance with the arrangement according toFIG. 6. The assembly of the cap100corresponds in terms of its sequence to the assembly of the cap60according toFIG. 5. One advantage of the embodiment according toFIG. 6can lie in the fact that only the claws38of the coupling part32act upon the supporting element30so that no additional reinforcement of the middle section of the supporting element30is achieved. The cap100inFIG. 6corresponds in all additional characteristics to the cap60inFIGS. 3 and 5. The structure of the wiper lever also corresponds to the above description.

It is clear from the foregoing description that the cap60is provided with elastically extendible locking means74or102, which are assigned to counter-locking means40or38of the wiper blade16.

A second embodiment of the wiper lever, in accordance with the invention, is explained in the following on the basis ofFIGS. 8 through 12. A wiper arm122and a wiper blade124belong to a wiper lever120. The wiper arm has a U-shaped cross-section (FIG. 11), in the area of the articulated connection between the wiper arm and the wiper blade. The U-shaped cross-section has U-legs126that form longitudinal walls where tongues128have been cut free and bent into the space between the U-legs. The arrangement of the bent tongues128is accomplished so that they lie across from one another and are directed opposite one another.FIG. 11also shows that an opening132is arranged near the free end134of the wiper arm122on its U-base surface130. Finally,FIG. 11also shows that, on the other side of the bent tongue pairs128(as viewed from the wiper-arm end134), there is a borehole136in each of the U-legs126, whose borehole axes are aligned with each other. Only a small partial section of the wiper blade124belonging to the wiper lever120is depicted inFIG. 12, which shows the wiper-blade side components for connecting the wiper blade to the wiper arm122. A holder138for an articulated bolt140, aligned transverse to the wiper blade longitudinal extension, is arranged on the upper side of the wiper blade124facing the wiper arm122. An adapter142is locked onto the articulated bolt in a manner that is known per se. This results in an articulated arrangement of the adapter142vis-à-vis the wiper blade, whereby the longitudinal axis of the articulated bolt140represents the articulated axis. Thus, the wiper blade124can oscillate freely within a certain angle around the articulation axis of the articulated bolt140(double arrow144inFIG. 12). The adapter142, manufactured of an elastic plastic, is provided on both its longitudinal ends146with fitting surfaces148,149, which are at a distance150from one another corresponding to the distance152between the inside wall of the U-base surface130and the bent tongues'128surface154that faces this inside surface (FIG. 12). Therefore, the distance150of the fitting surfaces148,149from one another corresponds to the thickness of the adapter142in the area of these fitting surfaces.FIG. 12also shows that a stop shoulder156directed toward the wiper blade124comes out of the fitting surface149of the adapter142and that a receptacle opening158is arranged in the adapter142.

In addition, a cap160also belongs to the wiper lever120. It is evident fromFIGS. 9 and 10that this cap has an essentially U-shaped cross-section. The distance161between the two U-legs162is coordinated with the width121of the wiper arm122. In addition,FIGS. 9 and 10show that the U-legs162extend beyond the U-base164with extensions163. Since the cap160is manufactured of an elastic plastic, the extensions163can be elastically deflected transverse to the longitudinal extension of the U-legs162. Aligned pivot pins166whose pin axes are aligned with one another are located on the facing inner sides of the extensions163. The diameter of the pivot pins166is coordinated with the diameter of the two boreholes136in the U-legs126of the wiper arm122in such a way that the cap160can lock onto the wiper arm with deflection of the extensions163in the direction of arrows167(FIG. 10), whereby the pivot pins166reach into the boreholes136in the wiper arm U-legs126that serve as rest receptacles. The arrangement of and coordination between the wiper arm122and the cap160are accomplished in such a way that a rotating movement (arrow168,FIG. 12) between the wiper arm and the cap is possible, because the distances121and161have been coordinated with each other. A locking nose170is arranged on each U-leg as a locking means at a distance from the pivot pins166near the other end of the cap160on the insides of the U-legs162, whereby the two locking noses are opposite one another and extend towards each other. A safety nose172, which extends out from the inside of the U-base164between the two U-legs162, is arranged in this area of the cap160on its U-base164. The wiper blade124corresponds, in terms of its further structure, to the wiper blade16already described.

As already mentioned, the cap160is connected in an articulated manner with the wiper arm122in the described manner. It is therefore pivoted on the wiper arm and is a part of the wiper arm. The pivoted arrangement between the wiper arm and the cap is achieved in that boreholes or rest receptacles136that are aligned with one another are arranged on the wiper arm on the U-legs126forming opposite longitudinal walls. Pivot pins or bearing pins166arranged on the cap walls (formed by the U-legs162) close to these longitudinal walls are assigned to these boreholes or rest receptacles. In order to connect the wiper blade124to the wiper arm122, the two wiper lever parts122,124must be brought into the pre-assembly position shown inFIG. 12. Then the wiper blade is moved towards the wiper arm in the direction of the assembly arrow174until the adapter142is adjacent to the inner wall of the U-base surface130of the wiper arm. Now the wiper blade is slid in the direction of arrow176towards the free end134of the wiper arm, whereby the fitting surfaces148,149of the adapter reach between the bent tongues128of the wiper arm or its surfaces154and wiper arm's U-base surface130. The sliding movement (arrow176) is limited by the fact that the stop shoulder156of the adapter hits the side (facing the adapter) of the bent tongue128that is located on the wiper-arm end134and that serves as a counter-stop shoulder157. In this position, the wiper blade124has now reached its operating position vis-à-vis the wiper arm122. In order to guarantee this position during wiper operation, the cap160is turned in the direction of the arrow168, whereby the safety nose172is guided through the opening132and reaches into the receptacle opening158of the adapter142. The coordination between the safety nose172and the two openings132and158is accomplished in such a way that the rotating movement of the cap160is not hampered by the opening132, but that the safety nose172dips so that it fits into the receptacle opening158of the adapter142that forms a safety recess. As a result, a relative movement between the wiper arm and wiper blade is no longer possible. So that the cap160does not unintentionally move against rotating arrow168during wiper operation and the safety feature between the wiper arm and the wiper blade cannot be neutralized, in the operating position depicted inFIG. 8the cap's160locking noses170grip under the counter-surfaces180of the wiper arm122that have been assigned to them and act as counter-locking means, which counter-surfaces are embodied on the bent tongues128. AsFIG. 8shows, the cap160also covers the end areas of the wind deflector strip sections52that are close to it. In particular, the free end182of the cap160facing away from the pivot pins166(FIG.12) is adapted to the cross-sectional profile of the wind deflector strip50in such a way that a harmonic transition is produced between the wind deflector strip and the cap.

It is also clearly evident from the foregoing description that the two designs of the wiper lever are provided with a cap60or160to cover the connection area between the wiper blade and the wiper arm. The advantages that are thereby yielded can be seen primarily in that the cap guarantees a harmonic transition between the two wind deflector strip sections52while simultaneously concealing the mechanics of the articulation and protecting the articulation from environmental influences.