GB2255004A

GB2255004A - A windscreen wiper arm

Info

Publication number: GB2255004A
Application number: GB9208547A
Authority: GB
Inventors: Jean-Pierre Jehannet; Maurice Journee
Original assignee: Paul Journee SA
Current assignee: Paul Journee SA
Priority date: 1991-04-26
Filing date: 1992-04-21
Publication date: 1992-10-28
Anticipated expiration: 2012-04-21
Also published as: GB9208547D0; GB2255004B; FR2675757A1; FR2675757B1; DE4210267A1; DE4210267B4

Description

2255004 1 A WINDSCREEN WIPER ARM HAVING IMPROVED AERODYNAMIC

CHARACTERISTICS This invention relates to windscreen wiper arms having an end portion articulated on a windscreen wiper blade.

Numerous improvements have been proposed in the past for modifying and improving the aerodynamic characteristics of a windscreen wiper for a motor vehicle, in particular where the windscreen wiper is intended for use on the windscreen itself. In this connection, it is to be understood that the term "windscreen wiper" as used in this specification is to be taken to mean a wiper for a glass surface, whether or not that surface is a surface of a front windscreen or some other part of the vehicle.

Among the various requirements that have to be satisfied by a windscreen wiper in operation, it is particularly important that the force applied by the wiping strip of the wiper blade on the glass surface itself should be relatively high. Furthermore, the value of this force should remain constant, or even be increased, when the vehicle is travelling at high speed. Currently, aerodynamic forces acting as a result of the forward movement of the vehicle, and arising from the displacement of the windscreen wiper itself over the swept surface, tend to lift the wiper blade away from the glass surface.

Among various improvements proposed in the past for ameliorating this tendency, attention is drawn in particular to the specification of the French published patent application No. FR 2 437 960A, which proposes a series of longitudinal slots in the upper faces of the yokes or stirrups that constitute the pressure distributing structure of the blade which couples the wiping strip of

2 the latter to the articulating end of the wiper arm. These slots enable air that penetrates into the interior of the stirrups of the pressure distributing structure (which are generally of U-shaped cross section) to flow through the upper faces of the stirrups. This avoids accumulation of air between the glass and the stirrups when the vehicle is travelling at high speed, which would cause an increase in aerodynamic pressure tending to lift the stirrups away from the glass.

However, it is found that such an improvement is insufficient, to the extent that the air which is evacuated from within the stirrups through the slots then encounters a further obstacle in the form of the end portion of the wiper arm itself. In the same way, and even when the upper faces of the stirrups are flat, the upper face of the end portion of the wiper arm, particularly when the latter also has a U-shaped cross section, forms an aerodynamic trap, so that this part of the wiper arm then behaves like a flap which tends to lift the wiper away from the swept surface.

In order to overcome the drawbacks discussed above, the invention proposes a windscreen wiper arm having one end articulated on a windshield wiper blade with at least one end portion of the arm lying adjacent to the wiper blade, the said end portion having an upper face arranged in facing relationship to an upper face of the blade and being formed with at least one aperture for free flow of air through the-end portion, whereby to improve the aerodynamic characteristics of the windscreen wiper.

According to a preferred feature of the invention, the or each said aperture is formed in the upper face of the end portion of the windscreen wiper arm.

3 i - Preferably, the blade comprises a pressure distributing structure carrying a wiping strip, the said structure comprising at least one yoke or stirrup of U-shaped cross section having slots formed in its upper face for flow of air therethrough, the aperture or apertures formed in the end portion of the arm being at least partially disposed facing the said slots.

Preferably also, the said end portion of the arm has a Ushaped cross section which at least partially surrounds the cross section of the stirrup or stirrups.

According to another preferred feature of the invention, the upper face of at least one said stirrup is formed with a plurality of longitudinal slots, the upper face of the end portion of the wiper arm having a plurality of longitudinally extending apertures.

A preferred embodiment of the invention will now be described in detail, by way of example only and with reference to the accompanying drawing, consisting of a single Figure, which is a top plan view of a windscreen wiper in accordance with the invention.

The windscreen wiper 10 essentially comprises a windscreen wiper arm 12 and a windscreen wiper blade 14. The latter, in the usual way, comprises a wiping strip, not shown, which is articulated about an axis X-X on to the end 16 of the wiper arm 12, through a structure which distributes the applied pressure. This pressure distributing structure may for example comprise a main stirrup or yoke 20 on which intermediate stirrups or yokes 22 are pivoted. In a similar manner to that described and shown in the French published patent specifications FR 2 050 605A and FR 2 437 960A, the flat upper face 22 of the main stirrup 20 is

4 1 - formed with a series of longitudinal slots 26. In the same way, the flat upper face 28 of the secondary stirrups 22 is formed with a series of longitudinal slots 30. The stirrups 20 and 22 have a generally U-shaped cross section (which cannot be seen in the drawing), comprising a central branch which incorporates the upper faces 24 and 28. The arrangement of the slots 26 and 30 permits free flow of the air which is trapped inside the stirrups, thus preventing accidental lifting of the windscreen wiper blade under the effect of the aerodynamic pressure which results from forward movement of the vehicle at high speed, and from the wiping movement of the wiper itself.

In the embodiment shown in the drawing, the windscreen wiper arm 12 has an end portion 32, which incorporates the end 16 already mentioned. This end 16 is pivoted on the wiper blade 14. The end portion 32 of the wiper arm 12 again has a U-shaped cross section, which at least partially surrounds, and follows, the external shape of the main stirrup 20. The substantially flat upper face 34 of the end portion 32 of the wiper arm overlies the right-hand half (as seen in the drawing) of the upper faces 24 and 28 of the main stirrup 20 and secondary stirrup of the wiper blade 14.

In order to facilitate the flow of air through the slots 26 and 30 towards the outside of the wiper blade, the flat upper surface 34 of the end portion 32 of the arm 12 is formed with-a series of longitudinal apertures 36. As is plainly shown in the drawing, these longitudinal apertures 36 are rectangular and overlie the slots 26 and 30 in facing relationship with them. It will thus be readily understood that the air passing through the slots 26 and 30, and also the air which passes between the parallel vertical faces (not shown) of the U-shaped sections of the 1 stirrups and of the end portion 32, can escape through the longitudinal apertures 36. In this way any accumulation of air which could give rise to aerodynamic lift of the windscreen wiper arm 12 is avoided.

Application of the invention in practice, as described in its particular embodiment above, is not limited to a windscreen wiper having a blade that includes a pressure distributing structure in the form of a plurality of distributing yokes or stirrups. It is equally applicable in the case of a windscreen wiper having a single articulated stirrup or yoke, or any other equivalent structure. In addition, the invention is applicable to all types of windscreen wiper, whether having a cross section that is U-shaped, flat, or of any other convenient shape.

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Claims

CLAINS

1. A windscreen wiper arm having one end articulated on a windshield wiper blade with at least one end portion of the arm lying adjacent to the wiper blade, the said end portion having an upper face arranged in facing relationship to an upper face of the blade and being formed with at least one aperture for free flow of air through the end portion, whereby to improve the aerodynamic characteristics of the windscreen wiper.

2. A windscreen wiper according to Claim 1, wherein the or each said aperture is formed in the said upper face of the end portion.

3. A windscreen wiper arm according to Claim 2, wherein the blade comprises a pressure distributing structure carrying a wiping strip, the said structure comprising at least one yoke or stirrup of U-shaped cross section having slots formed in its upper face for flow of air therethrough, the aperture or apertures formed in the end portion of the arm being at least partially disposed facing the said slots.

4. A windscreen wiper arm according to Claim 3, wherein the said end portion of the arm has a U-shaped cross section which at least partially surrounds the cross section of the stirrup or stirrups.

5. A windscreen wiper arm according to Claim 3 or Claim 4, wherein the upper face of at least one said stirrup is formed with a plurality of longitudinal slots, the upper face of the end portion of the wiper arm having a plurality of longitudinally extending apertures.

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6. A windscreen wiper arm constructed, arranged and adapted to operate substantially as described in the foregoing description with reference to the accompanying drawing.