WO2012041377A1

WO2012041377A1 - Windscreen wiper device

Info

Publication number: WO2012041377A1
Application number: PCT/EP2010/064558
Authority: WO
Inventors: Xavier Boland
Original assignee: Federal-Mogul S.A.
Priority date: 2010-09-30
Filing date: 2010-09-30
Publication date: 2012-04-05

Abstract

A windscreen wiper device (1) comprising an elastic, elongated carrier element, as well as an elongated wiper blade (2) which includes at least one longitudinal groove (3), in which groove a longitudinal strip (4) of the carrier element is disposed, which device (1) comprises a connecting device (7) for pivotally connecting an oscillating wiper arm (8) thereto, as well as a spoiler (10), wherein the spoiler (10) is hingeable through deformation between a first position, wherein said spoiler (10) has a symmetric profile, in the absence of a wind load thereon, and a second position, wherein said spoiler has a asymmetric profile, in the presence of a wind load thereon, with the special feature that said spoiler (10) and said wiper blade (2) are made in one piece, and wherein said spoiler has a hollow core (15) having a closed circumference.

Description

WINDSCREEN WIPER DEVICE The present invention relates to windscreen wiper device comprising an elastic, elongated carrier element, as well as an elongated wiper blade of a flexible material, which can be placed in abutment with a windscreen to be wiped, which wiper blade includes at least one longitudinal groove, in which groove a longitudinal strip of the carrier element is disposed, which windscreen wiper device comprises a

connecting device for pivotally connecting an oscillating wiper arm thereto, as well as a spoiler, wherein the spoiler is hingeable through deformation between a first position, wherein said spoiler has a symmetric profile, seen in cross- section of the wiper blade, in the absence of a wind load thereon, and a second position, wherein said spoiler has a asymmetric profile, seen in cross-section of the wiper blade, in the presence of a wind load thereon. Such a spoiler is also called an "air deflector".

Such a windscreen wiper device is generally known. The prior art windscreen wiper device is in particular designed as a "yokeless blade" or "flat blade", wherein use is no longer made of several yokes pivotally connected to each other, but wherein the wiper blade is biassed by the carrier element, as a result of which it exhibits a specific curvature. The spoiler and the wiper blade of the known windscreen wiper device are made in one piece.

Windscreen wiper devices actually used on cars fitted with windscreens exhibiting some degree of curvature are

sometimes subjected to a lifting effect at high speeds, which prevents the windscreen from being wiped correctly. This lifting effect is due to the following aerodynamic phenomenon. Streams of air along the car tend to escape vertically upwards along the axis of the car. Near the sides of the curved windscreen, however, the streams of air tend to pass horizontally along the sides. These streams of air create, mainly in the zones in which the windscreen wiper device meets them perpendicularly, a reduced pressure above the windscreen wiper device and an increased pressure between the windscreen and the windscreen wiper device. The resulting pressure, in spite of the mechanical pressure applied by the arm of the windscreen wiper device, causes the latter to lift away towards the front of the windscreen, thereby deteriorating the wiping pattern at higher driving speeds. A spoiler is often used to suppress said lifting effect .

A disadvantage of some windscreen wiper devices is that a specific wiper blade equipped with an asymmetric spoiler has to be designed and manufactured for an oscillating arm of a left hand drive (LHD) vehicle and for an oscillating arm of a right hand drive (RHD) vehicle. Obviously this requires the use of complex machinery, tools, with all the expenses involved. A further drawback is that mutually differing wiper blades with asymmetric spoilers for each type of oscillating arm (that is at LHD or at the RHD) require much space for storage both in a warehouse and in a shop. Still a further disadvantage is that a wiper blade equipped with an asymmetric spoiler meant to be mounted on an oscillating arm of a LHD vehicle is often actually mounted on an oscillating arm of a RHD vehicle, while such wiper blade equipped with an asymmetric spoiler meant to be mounted on an oscillating arm of a RHD vehicle is often actually mounted on an oscillating arm of a LHD vehicle. Such a reversed mounting of these wiper blades seriously affect the wiping qualities thereof particularly at high speeds, with all negative consequences involved. However, a symmetric form of said spoiler in case air streams of wind do not exercise a load onto said wiper blade have already been proposed by the same Applicant. Due to the symmetric form of said spoiler in case air streams of wind do not exercise a load onto said wiper blade, said wiper blade can be mounted on said oscillating arm of LHD and RHD cars. Further, by avoiding any reverse mounting of these wiper blades the spoilers or "air- deflectors" provided thereon will always be "in the right position". Due to the asymmetric shape of said spoiler in case a load is exercised thereon by air streams of wind, the wiping qualities will be guaranteed at all times. Said asymmetric shape of said spoiler, as already proposed, is then particularly provided with an incident air flow surface which extends in its longitudinal direction and essentially parallel to the windscreen to be wiped and faces the

relative wind and which, seen transversely to its

longitudinal extent, encloses an acute angle with said windscreen to be wiped.

It is an object of the invention to improve the prior art, i.e. to provide a cheaper windscreen wiper device being easy to manufacture.

It is noted that the present invention is not restricted to windscreen wiper devices for cars, but that it also relates to windscreen wiper devices for rail coaches and all other (fast) vehicles. In order to accomplish that objective, a windscreen wiper device of the kind referred to in the introduction according to the invention is characterized in that said spoiler is provided on said wiper blade at a side thereof facing away from the windscreen to be wiped, wherein said spoiler and said wiper blade are made in one piece, and wherein said spoiler has a hollow core having a closed circumference. Particularly, in said first position said spoiler has a symmetric profile having a triangular cross-section. More in particular, in said first position said hollow core has a triangular cross-section.

In one preferred embodiment of a windscreen wiper device according to the invention, said spoiler is hingeable between said first and second positions by means of a tilting web interconnecting said spoiler and said wiper blade. Preferably, said wiper blade includes opposing longitudinal grooves on opposite sides of said tilting web, in which grooves spaced-apart longitudinal strips of the carrier element are disposed, wherein neighboring ends of said longitudinal strips are interconnected by a respective connecting piece. More in particular, said spoiler comprises two subspoilers each on one side of the connecting device, wherein each subspoiler extends from the connecting device to a respective connecting piece, and wherein each

subspoiler is connected to the wiper blade or to

the longitudinal strips of the carrier element.

In another preferred embodiment of a windscreen wiper device in accordance with the invention, said wiper blade includes a central longitudinal groove, in which groove a central longitudinal strip of the carrier element is disposed.

Particularly, said spoiler is hingeable between said first and second positions by means of a flexible upper wall of said central longitudinal groove.

Preferably, said spoiler is made of a material deformable in the presence/absence of a wind load thereon. More in

particular, said spoiler is at least substantially made of a thermoplastic elastomer, elastic elastomer or (soft) PVC . Said asymmetric shape of said spoiler is particularly provided with an incident air flow surface which extends in its longitudinal direction and essentially parallel to the windscreen to be wiped and faces the relative wind and which, seen transversely to its longitudinal extent, encloses an acute angle with said windscreen to be

wiped .

The invention will now be explained in more detail with reference to figures illustrated in a drawing, wherein: figure 1 shows diagrammatically the flow of streams of air along the windscreen of a car; figure 2 is a diagram of a standard windscreen wiper device in a position parallel to the streams of air; - figure 3 is a cross-section of the same windscreen wiper device, but in a position at right angles to the streams of air; figure 4 illustrates the forces due to the tangential streams of air acting on the standard windscreen wiper device ; figure 5 is a total perspective, schematic view of a windscreen wiper device according to the invention; and figures 6 and 7 are cross-sectional views of different embodiments of the windscreen wiper device of figure 5.

Figure 1 shows a perspective view of the front portion of a car provided with a curved windscreen A, together with the direction of flow of the streams of air, the latter passing the vehicle upwards and along the sides. In a zone in which a windscreen wiper device of the usual standard form is positioned parallel to the streams of air, as shown in figure 2, nothing unusual occurs; on the other hand, in a zone as shown in figure 3, in which the streams of air flow practically at right angles to the direction of the

windscreen wiper device, this air cannot flow along the glass because of the wiper blade, and thus creates an increase in pressure (indicated by the + sign ) . Such an increased pressure also exists in the region of the hollow profile comprised between the flanges of the frame C

directed towards the windscreen. These flanges create further obstacles to the flow of air and assist in

maintaining the increased pressure. In addition, the streams of air which pass round the windscreen wiper device towards the upstream side tend to move away from the surface and create a reduced pressure zone (indicated by the - sign) , as is well known. These two forces Fx and Fz (which can be compared with the drag and the lift acting on a wing

section) have a resultant R which tends to lift the

windscreen wiper device against the mechanical pressure applied by the arm (see figure 4) . Figure 5 shows a preferred variant of a windscreen wiper device 1 according to the invention. Said windscreen wiper device is built up of an elastomeric wiper blade 2, in the longitudinal sides of which opposing longitudinal grooves 3 are formed, and of longitudinal strips 4 made of spring band steel, which are fitted in said longitudinal grooves 3. Said strips 4 form a flexible carrier element for the rubber wiper blade 2, as it were, which is thus biased in a curved position (the curvature in operative position being that of a windscreen to be wiped) . Neighbouring ends 5 of strips 4 are interconnected on either side of the windscreen wiper device 1 by means of connecting pieces 6 functioning as clamping members. In this embodiment, the connecting pieces

6 are separate constructional elements, which may be form- locked as well as force-locked to the ends 5 of strips 4. In another preferred variant, said connecting pieces 6 are in one piece with the strips 4 made of spring band steel. In the latter case said connecting pieces form transverse bridges for the strips 4, as it were. The windscreen wiper device 1 is furthermore built up of a connecting device 7 of plastic material for an oscillating wiper arm 8. Connecting device 7 may comprise clamping members 9 that are integral therewith, which engage round longitudinal sides of the strips 4 that face away from each other, as a result of which the connecting device 7 is firmly attached to the unit consisting of wiper blade 2 and strips 4. The oscillating wiper arm 8 is pivotally connected to the connecting device

7 about a pivot axis near one end. The preferred embodiment of figure 5 according to the invention comprises a spoiler 10 including two separate sub-spoilers 11. Each sub-spoiler 11 is detachably connected in its entirety to the wiper blade 2 on opposite sides of the connecting device 7. In figure 6 a cross-sectional view of the windscreen wiper device of figure 5 is shown, wherein corresponding parts have been designated with the same reference numerals. In the event that the spoiler 10 is not charged by the wind (figure 6a) , said spoiler 10 has a symmetric shape, seen in cross-section of the wiper blade 2 and seen with respect to its middle longitudinal plane perpendicular to the

windscreen to be wiped (shown in dashed lines) . In that case such wiper blades 2 can be mounted on oscillating arms 8 at both LHD vehicles and RHD vehicles, while any reverse mounting of these wiper blades 2 is by definition avoided. Thus the spoilers 10 provided thereon are always "in the right position". However, in the event that the spoiler 10 is subsequently charged by the wind in the direction of the arrows (figure 6b) , said spoiler 10 is hinged through deformation from the position of figure 6a into the position of figure 6b. In the latter position said spoiler 10 has an asymmetric shape, seen in cross-section of the wiper blade 2 and seen with respect to its middle longitudinal plane perpendicular to the windscreen to be wiped (shown in dashed lines) . Said asymmetric shape of said spoiler is then particularly provided with an incident air flow surface 12 enclosing an acute angle (a) with said windscreen to be wiped. As shown in figure 6 a web 13 interconnects said spoiler 10 and said wiper blade 2, while said longitudinal strips 4 are provided in said grooves 3 on opposite sides of said web 13. Said spoiler 10 and wiper blade 2 are in one piece of material deformable in the presence/absence of a wind load thereon, i.e. a material such as a thermoplastic rubber.

Figures 7a and 7b correspond to figures 6a and 6b,

respectively, on the understanding that the spoiler 10 is hingeable between said first and second positions by means of a flexible upper wall 14 of a central longitudinal groove 3 in which a central longitudinal strip 4 is inserted.

In both embodiments of figures 6 and 7 the spoiler 10 has an internal hollow core 15 having a closed circumference and having a triangular cross-section.

The invention is not restricted to the embodiments shown, but also extends to other preferred embodiments falling within the scope of the appended claims.

Claims

A windscreen wiper device (1) comprising an elastic, elongated carrier element, as well as an elongated wiper blade (2) of a flexible material, which can be placed in abutment with a windscreen to be wiped, which wiper blade

(2) includes at least one longitudinal groove (3) , in which groove

(3) a longitudinal strip

(4) of the carrier element is disposed, which

windscreen wiper device (1) comprises a connecting device (7) for pivotally connecting an oscillating wiper arm (8) thereto, as well as a spoiler (10), wherein the spoiler (10) is hingeable through

deformation between a first position, wherein said spoiler (10) has a symmetric profile, seen in cross- section of the wiper blade (2), in the absence of a wind load thereon, and a second position, wherein said spoiler (10) has a asymmetric profile, seen in cross- section of the wiper blade (2), in the presence of a wind load thereon, characterized in that said spoiler

(10) is provided on said wiper blade (2) at a side thereof facing away from the windscreen to be wiped, wherein said spoiler (10) and said wiper blade (2) are made in one piece, and wherein said spoiler (10) has a hollow core (15) having a closed circumference.

A windscreen wiper device (1) according to claim 1, wherein in said first position said spoiler (10) has a symmetric profile having a triangular cross-section.

A wind screen wiper device (1) according to claim 1 or 2, wherein in said first position said hollow core (15) has a triangular cross-section.

4. A windscreen wiper device (1) according to claim 1, 2 or 3, wherein said spoiler (10) is hingeable between said first and second positions by means of a tilting web (13) interconnecting said spoiler (10) and said wiper blade (2 ) .

5. A windscreen wiper device according to claim 4, wherein said wiper blade (2) includes opposing longitudinal grooves (3) on opposite sides of said tilting web (13), in which grooves (3) spaced-apart longitudinal strips (4) of the carrier element are disposed, wherein neighboring ends (5) of said longitudinal strips (4) are interconnected by a respective connecting piece

(6) .

6. A windscreen wiper (1) according to claim 5, wherein said spoiler (10) comprises two subspoilers (11) each on one side of the connecting device (7), wherein each subspoiler (11) extends from the connecting device (7) to a respective connecting piece (6), and wherein each subspoiler (12) is connected to the wiper blade (2) or to the longitudinal strips (4) of the carrier element.

7. A windscreen wiper device (1) according to claim 1, 2 or 3, wherein said wiper blade (2) includes a central longitudinal groove (3) , in which groove (3) a central longitudinal strip (4) of the carrier element is disposed .

8. A windscreen wiper device (1) according to claim 7, wherein said spoiler (10) is hingeable between said first and second positions by means of a flexible upper wall (14) of said central longitudinal groove (3) .

9. A windscreen wiper device according to any of the

preceding claims 1 through 8, wherein said spoiler (10) is at least substantially made of a material deformable in the presence/absence of a wind load thereon.

10. A windscreen wiper device according to claim 9, wherein said spoiler (10) is at least substantially made of a thermoplastic elastomer, elastic elastomer or (soft) PVC.