GB2151914A

GB2151914A - Wiper blade

Info

Publication number: GB2151914A
Application number: GB08430972A
Authority: GB
Inventors: Bruno Egner-Walter; Eckhardt Schmid
Original assignee: SWF Auto Electric GmbH
Current assignee: SWF Auto Electric GmbH
Priority date: 1983-12-29
Filing date: 1984-12-07
Publication date: 1985-07-31
Also published as: JP2651461B2; ES283670Y; IT8424204A0; DE3347440A1; GB2151914B; FR2557526B1; JPS60161240A; GB8430972D0; DE3347440C2; IT1181929B; FR2557526A1; ES283670U

Abstract

In a wiper blade assembly comprising a yoke 1 having side walls 10, 20, web 30, a pivot pin 50 projecting laterally on which a wiper arm can be articulated, and a wiper blade element 80, the spacing A between sidewall 10 face 52 of the pivot pin is greater than the maximum width of the wiper blade element so that the latter can be displaced into the yoke as far as web 30. The yoke may or may not have slots 31, and may be made of metal or plastics material. <IMAGE>

Description

SPECIFICATION Wiper blade for windscreen wiper systems, in particular on motor vehicles This invention relates to a wiper blade for windscreen wiper systems, in particular on motor vehicles, comprising a supporting yoke indirectly or directly holding a rubber-elastic wiper element, which supporting yoke has an at least substantially U-shaped cross-section with two side walls and a web connecting the side walls at least in sections, wherein one side wall holds a laterally projecting pivot pin on which may be articulated a wiper arm.

A wiper blade of this kind is, for example, known from the German patent No. 2,401,082. Here the supporting yoke has a laterally projecting pivot pin through which the wiper blade may be articulated to the wiper arm. Wiper blade and wiper arm can be articulated to each other laterally. This kind of fastening wiper blade and wiper arm is chosen to achieve a low overall height of the windscreen wiper. As is known a series of favourable properties is linked with a low overall height. Firstly a good wiping pattern can more likely be achieved than if the overall height is great. A low overall height of a wiper blade according to the DE-PS 2,401,082 is at least in that case only insufficiently ensured, when the wiper element runs perpendicu larly or almost perpendicularly below the web of the supporting yoke.As a matter of fact the sup porting yoke is so small that either possibly em ployed secondary supporting yokes or the wiper element would hit the lower edges of the side walls if, when operated on considerably curved window panes or areas of window panes they carry out a compensating motion in the direction of the supporting yoke. Such compensating motions are however necessary in order to provide that the contact pressure of the wiper element on the window pane remains the same everywhere, so that a wiping pattern free from strips is achieved. Moreover, the pivot pin of the wiper blade according to the DE-PS 2,401,082 is held on the supporting yoke by a hook engaging from be low, so that it is very difficult to achieve that the pivot pin is held free from lateral play.Thus the supporting yoke according to the DE-PS 2,401,082 is only under certain circumstances suitable for wiping motor vehicle window panes optimally.

An object of the present invention is to create a wiper blade of the type mentioned initially which has a particularly low overall height and ensures an immaculate wiping pattern.

According to the present invention there is provided a wiper blade for windscreen wiper systems, in particular on motor vehicles comprising a sup porting yoke indirectly or directly holding a rubber elastic wiper element, which supporting yoke has an at least substantially U-shaped cross-section with two side walls and a web connecting the side walls at least in sections, wherein one side wall holds a laterally projecting pivot pin on which may be articulated a wiper arm, characterised in that the spacing (A) between the other side wall and the front face of the pivot pin facing the said other sidewall is so much larger than the maximal width of the wiper element that, at least in the area of the pivot pin, the wiper element can dip into the supporting yoke as far as to the web.

Owing to the arrangement of wiper element and pivot pin according to the invention an extremely low wiper blade height is possible Thereby the compensation movements of the wiper element necessary for an adaptation to window pane curvatures are not limited till the uppermost supporting yoke area and thus not so much as usually. Therefore window panes with a greater curvature can also be wiped without stripes.

The wiper blade of short wiper blades can thereby be held below the web by means integrally formed with the supporting yoke, such as claws formed on it. As far as longer wiper blades are concerned a good contact pressure cannot so easily be achieved with means of this kind. It is therefore suggested to hold the wiper element below the web by means of secondary supporting yokes laterally articulated to the supporting yoke in the manner of a balance beam. Then, for example, the guidance can be achieved by claws laterally projecting from the secondary supporting yokes. These claws either engage solely on the wiper element or, in the case of an extremely long primary supporting yoke together with claws formed on the supporting yoke.

The application of the invention is possible both with plastics supporting yokes and with sheet metal supporting yokes. As far as the first application is concerned it is suggested to produce supporting yoke and pin as a single piece by injectionmoulding, because thereby it is ensured in an especially simple way to hold the pivot pin reliably on the supporting yoke, which in turn has a positive effect on the wiping pattern. For the sheet metal supporting yoke two supporting yoke portions are suggested as holding elements for the pivot pin.In a particular arrangement in the area of the pivot pin the U-shaped cross-section of the supporting yoke is larger than in the other areas, the side wall connected with the pivot pin in certain areas has a continuously increasing spacing from the longitudinal axis of the supporting yoke and holds the pivot pin on its frontface far from the longitudinal axis of the supporting yoke, and a wall extends between the side walls which holds the front face of the pivot pin closest to the longitudinal axis of the supporting yoke.

In one arrangement in the area of the pivot pin one side wall has a greater wall thickness than in the other areas and is penetrated by an aperture extending over its entire height, and the pivot pin is formed on the walls limiting the aperture and extending in the direction of the longitudinal axis of the supporting yoke.

In this arrangement the pivot pin is supported within a widening supporting yoke in addition to on the front faces also on both sides of its longitudinal axis by supporting yoke portions, because the side wall connected with the pivot pin due to its non-uniform spacing from the other side wall in certain areas extends laterally of the longitudinal axis of the pin. Thereby is achieved a high stability of the moving joint both with plastics and sheet metal supporting yokes, which fact in turn has a favourable effect on the wiping pattern.

In order to achieve the desired shape of sheet metal supporting yokes it is suggested to form the wall for supporting one front face of the pivot pin, which wall is positioned between the side walls, by means of a lug cut out of the web. Thereby it is advantageous to provide the cuts for forming the lug closely to the side wall to be connected with the pivot pin. After bending in the same direction curved bending edges are obtained, so that the optical impression of the wiper blade is improved However it is also possible to provide the cuts closely to the other side wall. Then the portion of the supporting yoke projecting laterally with the pivot pin can be made narrower due to its bent shape In order to make the pivot pin accessible from above, as a matter of fact that part of the web located above the pivot pin must also be cut out.

It is especially favourable for the wiping pattern, if the supporting yoke extends as closely as possible along the wiper element sides and if the side wall exposed to the air-stream covers the wiper element over a height as great as possible. Then the airstream on the wiper blade impinges on a smooth area in front of the wiper element and flows over it because, due to the narrow spacing between the side walls and the wiper element there is no space for it to flow underneath the supporting yoke. Therefore the wiper blade cannot be lifted from the window pane and the contact pressure and the wiping pattern remain the same.

In order to ensure that also in the case of a wiper blade having a pivot pin riveted with the supporting yoke the supporting yoke runs as closely as possible along the sides of the wiper element, it is recommended to laterally offset the wiper element relative to the longitudinal axis of the supporting yoke. This measure allows the side wall not connected with the pivot pin to run more closely alongside the wiper element.

By means of an oblique arrangement of the web, that means by an arrangement of web and side walls deviating from 90 degrees, a covering of the wiper element on the side exposed to the air stream can be achieved. This has the advantage that in spite of the good covering no greater amount of material is necessary for the production of the supporting yoke.

A reliable contact pressure and an immaculate wiping pattern can be achieved by articulating the wiper arm as closely to the window pane as possible. A wiper blade with an obliquely running web can simply be articulated in such a way by making use of the side wall being closer to the window pane for securing the pivot pin. In order to improve the guidance of the wiper blade and, consequently, the wiping pattern even more it is suggested to arrange the pivot p- at such a level of the side wall that the wiper arm end is on both sides covered over its entire height by the wall and by the side wall. Thus the guide surfaces are so large that an optimal guidance of the wiper blade is ensured.

Embodiments of the invention will now be de scribed by way of examples with reference to the accompanying drawings, in which: Figure 1 is a view in perspective of the support ing yoke of a first embodiment according to the invention; Figure 2 is a top view of the supporting yoke of Figure 1; Figure 3 is a section taken on the line Ill-Ill of Figure 2; Figure 4 is a section taken on the line IV-IV of Figure 1; Figure 5 is a view in perspective of a second wiper blade according to the invention, and Figure 6 is a section taken on the line VI-VI of Figure 5.

The wiper blade shown in Figures 1 to 4 has a supporting yoke 1 which is pressed from a thin steel sheet and bent in such a way that it has a Ushaped cross-section with two side walls 10, 20 and a web 30 connecting the side walls 10, 20. The web 30 is penetrated by holes 31, whereby a good aerodynamic behaviour of the wiper blade is achieved.

The U-shaped cross-section of the supporting yoke 1 is greater in its central area 2 than in the areas laterally thereof, whereby in the central area 2 one side wall 20 extends at a greater spacing from the longitudinal axis 40 of the supporting yoke than in the other areas, while the other side wall has the same spacing from the longitudinal axis 40 of the supporting yoke everywhere. As Figures 1 and 2 show the changes to the different spacings take place gradually, so that in the central area 2 the side wall 20 is curved. In the central area 2 a steel pivot pin 50 laterally projecting towards the longitudinal axis of the supporting yoke is held by the side wall 20. On this pivot pin is articulated a wiper arm 60, which ends in a hook 61, in a known manner through a plastics connecting member 70 having a U-shaped longitudinal section.The pivot pin 50 is riveted with the side wall 20 on its front face 51 far from the longitudinal axis 40 of the supporting yoke. On its front face 52 closer to the longitudinal axis 40 of the supporting yoke the pivot pin 50 is riveted with a wall 15, which extends between the two side walls 10 and 20.

The wall 15 of the supporting yoke 1 is made by two cuts in the sheet metal portion forming the web 30 in an approximately perpendicular direction relative to the longitudinal axis 40 of the supporting yoke and by one cut into the sheet metal portion forming the web 30 closely to the upper end 21 of the sheet metal portion forming the side wall 20 in the longitudinal axis 40 of the supporting yoke and by bending the lug formed thereby together with the sheet metal portion forming the side wall 20 in the direction of arrow P (Figure 4).

Thus the pivot pin 50 is riveted with two bent portions 15, 20 of the supporting yoke 1. Thereby it is especially advantageous that, due to the curved side wall 20, the pivot pin is in addition to the front faces 51, 52 also supported on both sides of its longitudinal axis 53, so that its fit free from play is ensured. Furthermore the side wall 20 extends in that area, where it is crossed by the hooked end 61 of the wiper arm, with a knee directed downwards, so that the upper side of the wiper arm 60 extends in a plane with the upper edge of the side wall 20.

This ensures a stream-lined shape for all edges of the entire upper windscreen wiper area.

As Figure 3 in particular shows the web 30 of the supporting yoke 1 is obliquely arranged to the two side walls 10 and 20. Here the side wall 20, which is connected with the pivot pin 50, extends closer to the window pane than the other side wall 10.

The wall 15 thereby extends as closely to the window pane as the side wall 20 and the pivot pin 50 is arranged at approximately half of the height of the wall 15, whereby the wall 15 and the side wall 20 are adapted to the height of the wiper arm end 61, so that the wiper arm end 61 is covered on both sides over its entire height. It is planned that the side wall 20 is exposed to the airstream.

Both on the front end and on the rear end of the supporting yoke 1 whose ends are not shown in the drawing, are formed claws 3 which encompass a wiper element 80 of rubber from above, which wiper element is arranged below the supporting yoke web 30. In known manner the wiper element 80 is constructed of a head 81 with a trapezoidal cross-section followed by a narrow tilting web 82 of rectangular cross-section and a wiper lip 83 having substantially triangular cross-section and resting against the window pane. As Figure 3 shows the spacing A between the side wall 10 and the front face 52 of the pivot pin 50 is greater than the width of the wiper element 80 in the area of the head 81 and thus greater than the maximal width of the wiper element 80.Therefore the wiper element 80 can dip into the supporting yoke 1 as far as to the web 30, when it moves across a curved area of a window pane. Because of this reason the contact pressure of the wiper element towards the window pane remains at least substantially constant, so that a wiping pattern without stripes is ensured with an extremely low overall height of the wiper blade. As the drawing shows the height of the supporting yoke 1 is thereby adapted to the height of the wiper element 80 in such a way that it is ensured that the wiper element 80 can only dip so far into the supporting yoke 1, that part of the wiper lip 83 remains outside. Thereby it is ensured that the window pane is not scratched by the supporting yoke 1 in any case.

A further advantageous feature of the wiper blade is that, due to an arrangement of the wiper element 80 laterally offset to the longitudinal axis 40 of the supporting yoke, the supporting yoke 1 with the side wall 10 and the wall 15 runs as closely as possible along the wiper element sides.

Thereby the web 30 can be made as narrow as possible. Because the web 30 is furthermore penetrated by holes 31, below the supporting yoke there is only a small area exposed to the airstream, so that also because of this the inclination of the wiper blade to be lifted from the window pane is diminished. Moroever the amount of material required for the production of the supporting yoke is small with the arrangement suggested. The supporting yoke 1 can also be made by deep drawing instead of pressing and bending.

The supporting yoke 4 shown in Figures 5 and 6, just as the supporting yoke 1, has a U-shaped cross-section with two side walls 10, 20 and a web 30 connecting the side walls 10, 20. However the supporting yoke 4 is injection-moulded of a plastics material together with the pivot pin 50. The injection mould is thereby formed in such a way that one side wall 20 in the area 2 of the pivot pin 50 has a larger wall thickness than in the other areas and is penetrated by an aperture 22 in the shape of a trapezoidal column extending over its entire height. The pivot pin 50 is thereby formed between the limiting walls 20a and 20b extending in the longitudinal direction of the supporting yoke.The spacing A between the side wall 10 not connected with the pivot pin 50 and the front face 52 of the pivot pin 50, which front face is conceived at the inner side of the limiting wall 20b is so much greater than the maximal width of the wiper element (not shown) that the latter can dip into the supporting yoke 4 as far as to the web 30. In contrast to the supporting yoke 1 previously described, the web 30 of the plastics supporting yoke 4 does not have holes, because holes could favour an unintended bending of the supporting yoke 4. It has, however, the same oblique arrangement of web 30 and side walls 10, 20. Due to this arrangement and due to the spacing A also in the case of this wiper blade an extremely low overall height and an optimal wiping pattern can be achieved. Thereby the wiper arm can also be optimally guided by the supporting yoke areas 20a, 20b, although it extends laterally of the wiper element.

Finally it is again pointed out that the wiper element 80, in addition to the claws 3 formed on the supporting yokes 1, 4, can be also held by further claws articulated on secondary supporting yokes.

These secondary supporting yokes should preferably be articulated to the supporting yoke 1,4 via pivot pins, which are arranged in the same way as to pivot pin 50 on the supporting yokes 1, 4, in order to provide that also in the area of these pivot pins the wiper element 80 can dip into the supporting yokes 1, 4 as far as to the web 30. In this case the claws of the secondary supporting yokes should be provided on lateral elongations of these supporting yokes.

Claims

1. A wiper blade for windscreen wiper systems, in particular on motor vehicles, comprising a supporting yoke (1,4) indirectly or directly holding a rubber-elastic wiper element (80), which supporting yoke has an at least substantially U-shaped cross-section with two side walls (10, 20) and a web (30) connecting the side walls at least in sections, wherein one side wall holds a laterally projecting pivot pin (50) on which may be articulated a wiper arm (60), characterised in that the spacing (A) between the other side wall and the front face (52) of the pivot pin (50) facing the said other side wall is so much larger than the maximal width of the wiper element (80) that, at least in the area of the pivot pin (50), the wiper element (80) can dip into the supporting yoke (1;4) as far as to the web (30).

2. A wiper blade according to claim 1, characterised in that the wiper element (80) is guided below the web (30) by means produced as a single piece with the supporting yoke (1;4).

3. A wiper blade according to claim 1 or claim 2, characterised in that the wiper element (80) is guided below the web (30) by at least one secondary supporting yoke which is laterally articulated on the supporting yoke (1;4) in the manner of a balance beam.

4. A wiper blade according to claim 3, characterised in that the secondary supporting yoke is articulated through a pivot pin laterally projecting from a side wall (20) of the supporting yoke (1;4) and has a greater spacing (A) between the other side wall (10) and the front face of the pivot pin facing it than the maximal width of the wiper element (80).

5. A wiper blade according to any one of the preceding claims, characterised in that the pivot pin (50) is supported on both front faces (51, 52) in a manner known as such by portions (20, 15;20a, 20b) of the supporting yoke (1;4).

6. A wiper blade according to claim 5, characterised in that the supporting yoke (4) is injectionmoulded from a plastics material together with the pivot pin (50).

7. A wiper blade according to claim 5, characterised in that the supporting yoke (1) is pressed and bent from sheet metal or deep drawn in a manner known as such, and that the pivot pin (50) is riveted on two portions (15, 20) of the supporting yoke (1) each forming a knee.

8. A wiper blade according to any one of claims 5 to 7, characterised in that in the area (2) of the pivot pin (50) the U-shaped cross-section of the supporting yoke (1) is larger than in the other areas, wherein the side wall (20) connected with the pivot pin (50) in certain areas has a continuously increasing spacing from the longitudinal axis (40) of the supporting yoke and holds the pivot pin (50) on its front face (51) far from the longitudinal axis (40) of the supporting yoke, and that a wall (15) extends between the side walls (10,20) which holds the front face (52) of the pivot pin (50) closest to the longitudinal axis (40) of the supporting yoke.

9. A wiper blade according to claim 7 or claim 8, characterised in that the wall (15) is made by two cuts into the sheet metal portion forming the web (30) and the cuts run approximately perpendicularly to the longitudinal axis (40) of the supporting yoke and by bending this portion once into the direction of the longitudinal axis (40) of the supporting yoke and by bending the lug formed by the cuts.

10. A wiper blade according to claim 9, characterised in that the cuts are positioned closely to the upper end (21) of the side wall (20) connected with the pivot pin (50).

11. A wiper blade according to claim 9, characterised in that the cuts are positioned closely to the upper end of the side wall (10) not connected with the pivot pin (50).

12. A wiper blade according to claim 6 or claim 8, characterised in that in the area (2) of the pivot pin (50) one side wall (20) has a greater wall thickness than in the others areas and is penetrated by an aperture (22) extending over its entire height, wherein the pivot pin (50) is formed on the walls (20a, 20b) limiting the aperture (22) and extending in the direction of the longitudinal axis (40) of the supporting yoke.

13. A wiper blade according to any one of the preceding claims, characterised in that the supporting yoke (1,4) runs as closely as possible along the wiper element sides and with a side wall (20) facing the side exposed to the airstream covers the wiper element (80) over a height as large as possible.

14. A wiper blade according to claim 13, characterised in that the wiper element (80) is laterally offset relative to the longitudinal axis (40) of the supporting yoke.

15. Wiper blade according to claim 13 or claim 14, characterised in that the side wall facing the side exposed to the airstream extends further to the window pane than the other side wall (10) because the web (30) is obliquely arranged.

16. A wiper blade according to any one of claims 13 to 15, characterised in that the pivot pin (50), which serves for articulating the wiper arm, is arranged as closely as possible to the window pane in use.

17. A wiper blade according to claim 15 or claim 16, characterised in that the wall (15) extends at least approximately as far as the side wall (20) and that the pivot pin (50) is arranged at such a level that the wiper arm (60) is covered on both sides over its entire height at its end (61) articulated to the supporting yoke (1;4).

18. A wiper blade according to claim 2 or claim 3, characterised in that the supporting yoke (1;4) and/or the secondary supporting yoke hold the wiper element (80) from above with claws formed on the front and on the rear ends.

19. A wiper blade according to any one of claims 5 to 18, characterised in that, for the purpose of being articulated to the pivot pin (50), the supporting yoke (1;4) is crossed by the wiper arm (60) at its portion (20) and this portion is formed in such a way that the wiper arm (60) does not have edges projecting beyond the supporting yoke (1;4).

20. A wiper blade for windscreen wiper systems substantially as herein described with reference to Figures 1 to 4 or Figures 5 and 6 of the accomapnying drawings.