The present invention relates to a windscreen wiper device comprising an elastic, elongated carrier element, as well as an elongated wiper blade of a flexible material, said wiper blade comprising a wiping element which can be placed in abutment with a windscreen to be wiped, which wiper blade includes a central longitudinal groove, in which groove a longitudinal strip of the carrier element is disposed, which windscreen wiper device comprises a connecting device for an oscillating arm, wherein said oscillating arm is pivotally connected to said connecting device about a pivot axis near one end thereof.

Such a windscreen wiper device is generally known. This prior art windscreen wiper device is designed as a so-called "flat blade" or "yokeless blade", wherein no use is 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 object of the invention is to provide an improved windscreen wiper device.

In order to accomplish that objective, a windscreen wiper device of the type referred to in the introduction is characterized according to the invention in that said groove extends in downward direction beneath the longitudinal strip for forming at least two longitudinal hollow channels on opposite sides of said wiping element, said channels each being defined by said longitudinal strip and a bottom of said groove. Said wiper blade thus has a lower profile than in the prior art resulting in better wind lift test results. Further, less raw material is used.

In a preferred embodiment of a windscreen wiper device in accordance with the invention each channel has an at least substantially V-shaped cross-section. In the alternative, each channel has an at least substantially U-shaped cross- section .

In another preferred embodiment of a windscreen wiper device according to the invention said wiping element consists of two tilting web grooves defining a strip-like tilting web therebetween, as well as a downwardly extending wiping lip on the tilting web, wherein said bottom of said groove and said tilting web are of a substantially W-shaped cross- section .

In another preferred embodiment of a windscreen wiper device in accordance with the invention said bottom is provided with stop surfaces on opposite sides of said wiping element, wherein said stop surfaces limit an oscillatory movement of said wiping element. Preferably, said stop surfaces are formed by said channels. The advantage is that the so-called "reversal noise" of the wiping element during said oscillatory movement is reduced.

In another preferred embodiment of a windscreen wiper device according to the invention said groove extends in upward direction above the longitudinal strip for forming a longitudinal hollow channel defined by said longitudinal strip and an upper surface of said groove. In another preferred embodiment of a windscreen wiper device in accordance with the invention said wiper blade is provided with a spoiler at a side thereof facing away from a windscreen to be wiped.

The invention will now be explained more in detail with reference to figures illustrated in a drawing, wherein

figure 1 is a perspective, schematic view of a preferred embodiment of a windscreen wiper device according to the invention, with and without an oscillating arm, respectively; and

figure 2 shows a cross-sectional view of a wiper blade as used in a windscreen wiper device of figure 1.

Figure 1 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 comprising a central or middle longitudinal groove 3, wherein a central or middle longitudinal strip 4 made of spring band steel is fitted in said longitudinal groove 3 (see figures 2 through 5) . Said strip 4 forms a flexible carrier element for the rubber wiper blade 2, as it were, which is thus biassed in a curved position (the curvature in operative position being that of a windscreen to be wiped) . An end of said strip 4 and/or an end of said wiper blade 2 is/are connected on either side of the windscreen wiper device 1 to respective connecting pieces or "end caps" 5. In this embodiment, the connecting pieces 5 are separate constructional elements, which may be form-locked, as well as force-locked to both ends of said strip 4/said wiper blade 2. In another preferred variant, said connecting pieces 5 are in one piece with the strip 4 made of spring band steel. The windscreen wiper device 1 is furthermore built up of a connecting device 6 for connecting an oscillating wiper arm 7 thereto. The oscillating wiper arm 7 is pivotally connected to the connecting device 6 about a pivot axis near one end. The preferred embodiment of figure 1 according to the invention comprises a spoiler or "air deflector" 8 which is made in one piece with the rubber wiper blade 2 and which extends along the entire length thereof. The connecting device 6 with the wiper blade 2 is mounted onto the oscillating arm 7 as follows. A joint part 9 being already clipped onto the connecting device 6 is pivoted relative to the connecting device 6, so that said joint part 9 can be easily slided on a free end of the oscillating arm 7. During this sliding movement a resilient tongue 10 of said joint part 9 is initially pushed in against a spring force and then allowed to spring back into said hole 11 of said oscillating arm 7, thus snapping, that is clipping the resilient tongue 10 into the hole 11. This is a so-called bayonet-connection. The oscillating arm 7 together with the joint part 9 may then be pivoted back in a position parallel to the wiper blade 2 in order to be ready for use. By subseguently pushing in again said resilient tongue 10 against the spring force (as if it were a push button), the connecting device 6 and the joint part 9 together with the wiper blade 2 may be released from the oscillating arm 7. Dismounting the connecting device 6 with the wiper blade 2 from the oscillating arm 7 is thus realized by sliding the connecting device 6 and the joint part 9 together with the wiper blade 2 in a direction away from the oscillating arm 7. The connecting device 6 comprises two cylindrical protrusions 12 extending outwards on either side of said connecting device 6. These protrusions 12 pivotally engage in identically shaped cylindrical recesses 13 of the plastic joint part 9. Said protrusions 12 act as bearing surfaces at the location of the pivot axis in order to pivot the joint part 9 (and the oscillating arm 7 attached thereto) about the pivot axis near one end of the oscillating arm 7.

Although not shown in figure 1, but fully understood by a skilled person, said oscillating arm 7 is connected to a mounting head fixed for rotation to a shaft driven by a small motor. In use, the shaft rotates alternately in a clockwise and in a counter-clockwise sense carrying the mounting head into rotation also, which in turn draws said oscillating arm 7 into rotation and by means of said connecting device 6 moves said wiper blade 2.

With reference to figure 2 the wiper blade 2 comprises a wiping element 14. Said wiping element 14 consists of two tilting web grooves 15 defining a strip-like tilting web 16 between them, as well as a downwardly extending wiping lip 17 on the tilting web 16. Said wiping lip 17 rests with its free end on a windscreen to be wiped. In action said wiping lip 17, as if it were a hinge, tilts in its oscillation reversal positions.

As can be seen in figure 2, the central groove 3 extends in downward direction beneath the longitudinal strip 4 for forming two longitudinal hollow channels 18 on opposite sides of the wiping element 14, said channels 18 each being defined by said longitudinal strip 4 and a bottom 19 of said groove 3. Said bottom 19 is provided with stop surfaces 20 on opposite sides of said wiping element 14 to limit the oscillatory movement of said wiping element 14 in said second position. In fact, these stop surfaces 20 are formed by bottoms of the downwardly extending channels 18.

Sard central groove 3 also extends in upward direction above the longitudinal strip 4 for forming a longitudinal hollow channel 21 defined by said longitudinal strip 4 and an upper surface 22 of said groove 3. This is realized for facilitating insertion of said longitudinal strip 4 inside said groove 3 and for reducing the amount of raw material used in order to minimize costs and weight.

The invention is not restricted to the variants shown in the drawing, but it also extends to other preferred embodiments that fall within the scope of the appended claims.