0 t :22 2:2 o7 E-, __1 Windscreen wiper device The invention relates to
a-windscreen wiper device having at least one windscreen wiper, which has a wiper blade adapted to be mounted on a driven wiping arm, and having a retaining body on which a wiping lip, adapted to rest on an outer surface of the windscreen, is pivotally arranged.
In the case of known windscreen wiper devices of this type, which are used in particular on motor vehicles, a wiping arm of a windscreen wiper is fastened on a driven wiper shaft. At the free end of the wiping arm, a retaining clip, on which the wiper blade of the windscreen wiper is fastened, is hinged. The wiper blade has a retaining body, which is fastened to the retaining clip. Arranged on the retaining body, by means of a connecting piece, is a wiping lip of the wiper blade. The centrally arranged connecting piece permits a swivelling movement of the wiping lip with respect to the vertical axis of the wiper blade. Depending on the wiping direction of the windscreen wiper, the wiping lip consequently assumes various swivelled positions.
In order to avoid the wiper blade freezing to the windscreen in cold weather, windscreen wiper devices are known in which a heating device is provided on the wiper blade.
German Offenlegungsschrift 3,134,083 discloses a windscreen wiper device in which channels for a heating medium are provided on the wiper blade. These heating medium channels are connected to a compressed-air or pressure-fluid source with a heating device.
German Utility Model 1,989,712 discloses a windscreen wiper device having a wiper blade which is provided with a battery-operated heating element. In one embodiment, the heating element is arranged in the region 2 of the connecting piece on wiper blade.
Another windscreen wiper device according to German Auslegeschrift 2,309, 902 describes a wiper blade on which the leaf springs arranged on the retaining body are used as heating elements. The heating effect of the heating elements is achieved by the resistance of the leaf springs to an electric current.
In the case of the windscreen wiper devices known in the prior art, although the swivel-moveably arranged wiping lip of the wiper blade can be heated, it cannot be adapted specifically to the various operating conditions of the windscreen wiper device. As a result, the cleaning performance of the windscreen wiper device is impaired.
The present invention seeks to provide a windscreen wiper device in which an adaptation of the wiping lip to various operating conditions of the windscreen wiper device is possible.
According to the present i provided a windscreen wiper device, having at least one windscreen wiper, which has a wiper blade adapted to be mounted on a driven wiping arm, and having a retaining body on which a wiping lip, adapted to rest on an outer surface of the windscreen, is pivotally arranged, wherein means by which pivoted positions of the wiping lip in relation to the retaining body can be achieved are arranged on the wiper blade.
The means arranged on the retaining body of the nvention there is the. wiper blade permit a specific influence to be brought to bear on the swivelled position of the wiping lip in relation to the retaining body. The major advantage of the new windscreen wiper device is the improvement in the cleaning effect at high travelling speeds. With the means arranged on the wiper blade, the wiping lip can be fixed in such a way that a stiffening of the wiper blade is achieved. The flow around the wiper blade ca n be optimized under increasing wiping frequency by the wiping lip assuming different j tl.
3 swivelled positions in relation to the vertical axis of the wiper blade, depending on the wiping direction. Furthermore, smearing after the wiper blade can be reduced by setting the swivelled position of the wiping lip. Finally, the service life of the wiper blade can be increased by keeping the wiping lip in a defined position when the windscreen wiper device is in the rest position.
An advantageous development of the invention provides for the means to be arranged in the region of a connecting piece provided centrally between the retaining body and the wiping lip.
An advantageous embodiment provides for a hollow body, the volume of which can be changed by a change in its internal pressure, to be arranged between the wiping lip and the retaining body. The hollow body, which is preferably closed at its one front end and is connected at its other front end to a unit generating positive pressure or negative pressure, brings about a swivelling movement of the wiping lip, which is dependent on the change in volume of the hollow body.
In the case of large wiper blades in particular, it may be advantageous if a hollow body is provided in each case on the two longitudinal edges of the connecting piece.
The production of the wiper blade becomes particularly simple if the hollow bodies are integral with the wiper blade.
An advantageous further development provides for the hollow bodies to be designed with bellows-like side walls. The bellows-like side walls are designed so as to be distinctly less stiff than the centrally arranged connecting piece.
Another embodiment of the invention provides for an induction coil, arranged on a wiper blade part, to be provided in the region of the connecting piece, which coil interacts with a metal pole arranged on the opposite wiper blade part. If a current flows through the induction coil, the opposite metal pole is attracted by the 4 magnetic effect brought about. This brings about a swivelling movement of the wiping lip. Instead of the metal pole, magnetizable particles, which are already incorporated in the rubber blend of the wiper blade, mayalso act. Similarly, it may be provided that the induction coil interacts with an opposite field pole, which is designed as a permanent magnet.
An advantageous further development provides for an arrangement of induction coil and metal pole to be provided in each case in the region of both longitudinal edges of the connecting piece. This is of advantage in particular in the case of large wiper blades.
A further advantage of the arrangement of induction coil and metal pole provided on the wiper blade is that a heating effect of the wiper blade can be produced by means of an increased flow of current. In this case, such a design is possible in which a heating current with an increased frequency is superimposed on a signal for changing the swivelled position of the wiping lip. As a consequence of this measure, an "increased heating effect" of the wiper blade is controllable.
Two embodiments of the invention will now be described by way of example with reference to the drawings, in which:
Fig. 1 shows a diagrammatic section through a wiper blade of a first embodiment of the invention and Fig. 2 shows a section according to Fig. 1 of another embodiment of the invention.
The wiper blade (1), shown in Fig. 1, of.a windscreen wiper device (not shown) is fastened on a retaining clip (2) which is fastened swivelmoveably on a wiper arm (not shown). For this purpose, reliefs (3a, 3b), into which the retaining clip (2) engages, are provided on a retaining body (3) of the wiper blade (1). Arranged centrally on the retaining body (3) is a connecting piece (4), which connects the retaining body (3) to a wiping lip (5). The wiping lip (5) has a wiping edge (6), which rests on a windscreen (7) to be cleaned.
A -1 X, Arranged in the region of the connecting piece (4) are hollow bodies (8, g), which are provided on both sides of the connecting piece (4). The hollow bodies (8, 9) extend over the entire length (running perpendicularly to the plane of the drawing) of the wiper blade (1).
Bellows-like side walls (8a, 9a) are provided on the sides of the hollow bodies (8, 9) opposite the connecting piece (4). While the one front end of the hollow bodies (8, 9) is closed, a unit with which the internal pressure of the hollow bodies (8, 9) can be changed is arranged on the other front end. This unit (not shown in the drawing) may be a pressure or negative-pressure source. A change in the internal pressure of the hollow bodies (8, 9) also brings about their change in volume. If, for example, the internal pressure of the hollow body (8) is increased, the wiping lip (5) executes a swivelling movement counterclockwise and assumes a position (14) which is drawn in by broken lines. The wiping lip (5) consequently assumes a swivelling angle (11) in relation to the vertical axis (10) of the wiper blade (1). In the same way, by impinging the hollow body (9), the wiping lip (5) can be brought into a swivelled position (12) in which the wiping lip (5) assumes a swivelling angle (13) in relation to the vertical axis (10).
The impingement of the hollow bodies (8, 9) is performed dependently on the respective operating conditions of the windscreen wiper device. With increasing travelling speed, for example an increase in pressure in both hollow bodies (8, 9) can cause. the wiper blade (1) as a whole to be stiffened. ' Depending on the wiping direction of the windscreen wiper, the hollow bodies (81 9) can be impinged alternately. The frequency of the change in pressure in the hollow bodies (8, 9) can be performed in a simple way with a simple microcomputer system, the boundary conditions being specified. The adaptation of the swivelling angle (11, 13) to the respective operating conditions of the windscreen wiper device has the effect of achieving 1.1 k.
6 an improved cleaning performance of the wiper blade (1). In particular, the flow around the wiper blade (1) can be optimized. Furthermore, a possible smearing after the wiper blade (1) can be reduced.
In the rest position of the windscreen wiper device, the wiping lip (5) can be positioned by the hollow bodies (8, 9) in such a way that no premature wear effects or damage to the wiping edge (6) occur.
The wiper blade (15) shown in Fig. 2 has a retaining body (16), on which reliefs (16a, 16b), into which a retaining clip (17) engages, are provided. The retaining body (16) is connected via a centrally arranged connecting piece (18) to a wiping lip (18), on which a wiping edge (20) is formed. The wiping edge (20) rests on a windscreen (21) to be cleaned. Reliefs (31, 32) in the form of interstices of approximately triangular cross-section are provided laterally in the region of the connecting piece (18). Induction coils (22, 23), which are connected to a power supply unit (not shown in the drawing), are arranged on the upper wiper blade part, facing the retaining body (16). Arranged opposite the induction coils (22, 23) on the wiper blade part respec tively facing the wiping lip (19) are metal poles (24, 25), which interac t with the induction coils (22, 23).
If, for example, current flows through the induction coil (22), its magnetic effect generates a force of attraction on the metal pole (24) arranged on the wiping lip (19).
This brings about a swivelling movement of the wiping lip (19) from the vertical position (2.6) into the position (27) shown in Fig. 2. The wiping lip (19) consequently swivels about a swivel axis, which lies approximately in the centre of the connecting piece (18) and covers a swivelling angle (28) in relation to the vertical posi tion (26). In the same way, the arrangement (23, 25) brings about a swivelling movement of the wiping lip (19) into a swivelling position (29) in which the wiping lip (19) is swivelled through a swivelling angle (30) in relation to the vertical position (26).
p 4 7 The metal poles (24, 25) may also be designed as magnetizable particles, which are incorporated in the wiping lip (19) in the region of the connecting piece (18). The operating principle of the embodiment of Fig. 2 may correspond to that of Fig. 1.
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