DE9007728U1 - Windscreen wiper system - Google Patents

Description

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The invention relates to a windshield wiper system, in particular for passenger cars, with a wiper arm having a swivel drive, which has a bearing housing that can be swiveled about a swivel axis and at the free end a pivot bearing for a wiper blade that can be guided essentially parallel across the windshield, and which can be swiveled about a bearing axis into a rest position in the area of the lower edge of the windshield, whereby the wiper blade is approximately parallel to the wiper arm both in the rest position and in an approximately middle working position, and with a control gear assigned to the swivel drive in the bearing housing, which has a control element fixed to the vehicle during the parallel guidance of the wiper blade and a scanning element fixed to the wiper arm that interacts with it and which is deactivated during the swiveling into the rest position, with a changeover device for changing between the in-function state and the in-function state of the control gear in the approximately middle working position, and with an actuator.

Such a windscreen wiper system can be found, for example, in US-A 3,688,334. The switching of the control element in this windscreen wiper is carried out by a bolt that can be moved by means of the actuator connecting a driver either to a part fixed to the vehicle or to a movable part that forms a bearing housing of the control gear and on which the swivel drive engages. The swivel axis of the wiper arm lies parallel to the bearing axis on the bearing housing that can be swiveled around the axis. The control gear

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The drive comprises four gears that are connected in pairs by means of two toothed belts. As long as the driver, the bearing axle and the gears arranged on it are held fixed to the vehicle, the wiper arm pivots in the opposite direction to the bearing housing, whereby its pivot angle is greater than the pivot angle of the bearing housing due to a gear ratio in the gear area. If the driver is fixed to the wiper arm, the pivot angle of the wiper arm corresponds to that of the bearing housing and the wiper arm pivots with it.

US-A 2,607,065 shows a windshield wiper with a two-part, length-adjustable wiper arm, in which an actuator contains a Bowden cable, via which a lever is pivoted, which pre-tensions a spring. The pivot drive is stopped when a middle working position is reached, in which the tensioned spring pivots the front part of the wiper arm into the parking position about a joint, which in this position lies in the pivot axis. Moving to the parking position tensions a counteracting spring, so that when switched on after pivoting the lever before inserting the pivot drive, the front part of the wiper arm should pivot into the middle working position. The control gear contains a vehicle-mounted control element for both operating modes.

The invention has now set itself the task of designing a control gear that is as simple as possible for a windshield wiper system whose wiper blade can be guided parallel to the entire windshield and can be pivoted approximately parallel to the wiper arm with the latter to the lower edge of the windshield. In addition, the windshield wiper system should also be able to be equipped with wiper arms that can be adjusted in length.

According to the invention, this is achieved in that the pivot axis and the bearing axis are coaxial, and the pivot angle of the wiper arm, starting from the approximately middle working position, is larger for pivoting into the rest position than for the wiping movement in the same direction.

The increased swivel angle for moving the wiper arm from the middle working position to the almost horizontal rest position along the lower edge of the window is determined when the operating mode is changed using the actuator.

Since a relative movement between the control element and the wiper arm-fixed scanning element is not possible when the control gear is not in operation, this also prevents the accidental twisting of the wiper blade due to friction changes between the wiper blade rubber and the windshield. If the windshield wiper is required, the wiper arm is swiveled back from the rest position to the approximately middle initial working position and the operating mode is changed, whereby the swivel angle is reduced, the control gear is activated and the rotary drive is released. This preferably also causes an extension of the swiveling wiper arm.

There are various options when it comes to the structural design of the windshield wiper system.

Based on the known design with a swivel drive fixed to the vehicle, the actuator can be mounted on the control element, on the bearing housing of the wiper arm or also fixed to the vehicle. If the actuator is fixed to the vehicle, the swivel drive cannot

not only be fixed to the vehicle, but also be assigned to the control element or the bearing housing.

Preferred embodiments can provide that the control gear is arranged in a bearing housing of the wiper arm and the swivel drive engages the bearing housing, wherein it is advantageous if the swivel axis of the wiper arm, which is coaxial with the bearing axis, is formed on the control element.

A preferred embodiment provides that the changeover device comprises two locking pins that abut one another and can be moved together perpendicular to the bearing/pivot axis, the first of which is spring-loaded and arranged in a radial bore, and the second of which is provided with the hinge pin and can be moved in the bearing housing, whereby the control element has an opening into which one of the two locking pins engages. For example, a lifting magnet can be used as the actuator, which acts on the second locking pin so that the hinge pin that determines the pivot angle moves between two positions.

Preferably, however, an electric motor with a drive worm, for example, is used as the actuator, whereby the locking pin provided with the hinge pin can be moved continuously. The displacement of the engagement point of the swivel drive can therefore not only be used to increase the swivel angle 0 for swiveling into the rest position, but also to change the wiping angle itself, which decreases as the distance between the engagement point of the swivel drive and the swivel axis increases.
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Single-arm wipers require a higher wiper speed due to the large overall swivel angle in order to achieve the same wiping frequency as windshield wiper pairs. The higher wiper blade speed can have an adverse effect on the wiping quality, especially at high driving speeds, so that visibility is impaired by streaking, lifting off due to aquaplaning of the wiper rubber or the like. If a single-arm windshield wiper system according to the invention is arranged off-center in the driver's side half of the windshield, the wiper blade speed can be reduced by reducing the wiping angle. A central arrangement can also lead to asymmetry if the point of action of the swivel drive is moved at an angle to the longitudinal axis of the wiper arm. The slowed-down wiper blade then sweeps over the driver's side half of the windshield over its entire surface, while an outer area 0 on the passenger side half of the windshield is not covered. In a two-arm windshield wiper system, for example, only the point of action of the swivel drive of the driver's side wiper arm could be moved outwards, resulting in a smaller wiping angle and a lower wiper blade speed, while on the passenger side a larger wiper angle and a higher speed occur, so that the entire surface of the windshield is still cleaned. It is also conceivable to change the crank length of the swivel drive to change the wiping angle.

In the version described so far, the actuator is used to change the locking mechanism, whereby the swivel drive swivels the wiper arm 5 in both operating modes.

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The swivel drive can also be used just to swivel the wiper arm while the wiper blade is guided parallel, and its swiveling through the larger angle into the rest position is taken over by the actuator when the control gear is not working. In this case, a further design provides that the actuator is assigned a switching element that stops the swivel drive in the middle working position and that the swivel drive is provided on a support body that can be swiveled through the larger angle by means of the actuator and that is rigidly connected to the control element. A hollow shaft is preferably formed in the common bearing and swivel axis, through which an axle bolt connects the support body to the control element and is mounted so that it can swivel around the bearing/swivel axis in a bearing fixed to the vehicle.

There are also various options for the design of the control gear. A preferred design provides that a spring-loaded control pin is slidably mounted in the control element and the sensing element is formed by a control cam formed in the bearing housing, which rests on the control pin. The contact end of the control pin is preferably provided with a friction-reducing roller. The control pin is guided in the control element along its entire length, with the roller being arranged on a part that protrudes from the guide and the sensing element partially covering the control element. The elements of the control gear can also be swapped.

Since a roughly straight parallel guide of the wiper blade requires a change in the effective wiper arm

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length, i.e. a change in the distance between the pivot bearing and the swivel bearing is necessary, a further preferred embodiment provides that the wiper arm consists of at least two telescopically movable parts and two cable spools are mounted on the control element so that they can rotate in opposite directions via a toothing, wherein the parallel guide of the wiper blade comprises a cable pull which is connected on the one hand to a rotary disk carrying the wiper blade and on the other hand is wound up on the cable spools so that it can be pulled out.

This design does not contain any components that take up a lot of space, so that the windshield wiper system can be installed in any passenger car. The space required for the windshield wiper system according to the invention is roughly the same as for conventional, simple windshield wipers.

Across the two sections of the cable, there is a type of coupling of the bearing housing with the rotating disk carrying the wiper blade, similar to a rigid parallel guide, whereby the ends of the cable wound onto the cable spools ensure the cable length adjustment required by the change in length of the wiper arm. The shortening of the extended wiper arm is achieved in particular by a coil spring, which constantly applies pressure to the telescopically arranged parts of the wiper arm in the sense of an extension. The extension is taken into account by the unwinding cable lengths when the control pin follows the control curve when the wiper arm is pivoted, and thus drives the cable spools so that the cable is released. The coil spring thus also indirectly applies pressure to the control pin.

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When the wiper arm is jerked, an opposite movement sequence occurs. The control cam moves the control pin, which drives the cable spools in opposite directions via a gearing, so that the two cables are drawn in, whereby the wiper arm is compressed against the coil spring. The parallel guidance via a cable pull described is only one possible design. Instead of a cable pull and two cable spools rotating in opposite directions, other types of gear would also be conceivable, for example a conical-toothed rolling element that connects a conical-toothed rotating disk of the wiper blade to a conical-toothed, length-adjustable shaft, whereby a spring is also used.

If the two cable spools are coaxial, they can have a relatively large diameter, which means that an additional reduction gear between the control pin and the cable spool is not necessary. In order to achieve exact parallel guidance, the rotary disk for the wiper blade would have to have the same large diameter. Since the rotary bearing of the wiper arm and the wiper blade holder must be kept as narrow as possible, another design provides that the rotary disk of the wiper blade has a toothing into which a drive worm driven by the cable engages, the standstill of which blocks the rotation of the wiper blade. The reduction is achieved here by using a worm to drive the rotary disk, so that the cable spools can also have the larger diameter. Instead of the drive worm, another suitable reduction gear could also be provided. The drive worm can be assigned a cable disk over which the cable is guided, whereby a positive connection between the cable and the cable

pulley can be designed, for example by thickening the rope and recesses in the pulley. A design is preferably selected in which the drive worm is connected to a rope drum on which the ropes of the cable pull are wound in opposite directions.

Since windshields, especially in passenger cars, are not rectangular but often trapezoidal, exact parallel guidance of the wiper blade does not result in the complete coverage of the window from side edge to side edge or within the desired wiping area. By using different diameters or selectable reductions between the drive worm and the rotating disk, a customized trapezoidal wiping surface can also be achieved, whereby the wiper blade rotates in relation to the wiper arm by an angle of rotation that is larger than the swivel angle. By designing the control curve accordingly, the wiping surface can also be adapted to a curved longitudinal edge of the window.

For pressing the wiper blade onto the windshield, a further preferred embodiment provides that the wiper arm is mounted on the bearing housing so that it can pivot about a transverse axis and is acted upon by a coil spring that presses the wiper blade onto the windshield and that acts on the wiper arm on the one hand and the control element on the other hand eccentrically to the pivot axis. The eccentric fixation of the pressure spring on the control element has the advantage that the pressure force is increased with increasing pivot angle, since the spring tension changes due to the extension of the spring.

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The coil spring of the wiper arm can also be used to press the wiper blade in place, if a transverse axis is provided in the part of the wiper arm that is connected to the bearing housing on the side of the cable facing away from the wiper blade, on which the remaining part of the wiper arm is pivotably mounted. The cable held under tension by the spring is therefore closer to the window than the transverse axis, so that the wiper arm and thus the wiper blade are subjected to pressure towards the window. In the area of the lower edge of the window, a bracket can be provided on the vehicle that the wiper arm runs onto when it is pivoted into the rest position, whereby the wiper blade lifts off the window.

This prevents the wiper blade from touching the windscreen when in the resting position, so that it does not freeze in winter and does not stick in summer due to dirt and sun.

The invention is now described in more detail below with reference to the figures of the accompanying drawings, without being limited thereto.

Show it:

Fig. 1 to 3 Top views of windshields of

Motor vehicles with windscreen wiper systems according to the invention, the wiper arm being shown in several positions,

Fig. 4 is a section along the line IV-IV of Fig. 0 through a first embodiment of a disc winder

shearing system,

Fig. 5 is a schematic horizontal section,

Fig. 6 is a section along the line VI-VI of Fig. 4,

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Fig. 7 a section along the line VII-VII of Fig. 4 in an approximately middle working position of the wiper arm,

Fig. 8 the same section in a lateral reversal position of the wiper arm,

Fig. 9 and 10 sections along lines IX-IX and X-X in Fig. 8,

Fig. 11 a schematic representation of the wiper arm and wiper blade in the middle working position and a lateral reversing position, Fig. 12 a section through the bearing housing of a

second embodiment according to line XII-XII of Fig. 14 in the vehicle-fixed arrangement of the control element,

Fig. 13 the same section in the wiper arm-fixed arrangement of the control element,

Fig. 14 is a section along the line XIV-XIV of Fig. 15, and

Fig. 15 is a section along the line XV-XV of Fig. 14.

A motor vehicle 1 has an approximately trapezoidal, curved and possibly more strongly bent back windshield 32, to which a single-arm windshield wiper system is assigned. This is provided with a wiper arm 29 that is adjustable in length and has a bearing housing 30, which is shown in Fig. 1 to 3 in different positions during the movement sequence controlled by the swivel drive 5. A wiper blade 16 is rotatably mounted on the wiper arm 29. The windshield wiper system is arranged on the motor vehicle 1 below the windshield 32.

Fig. 1 shows a central arrangement of the windscreen wiper system, with the wiper arm 29 in

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the middle working position extends over the height of the window 32, in which it has its shortest length, and in which the wiper blade 16, which is guided almost parallel, is aligned with the wiper arm 29. When the wiper arm 29 is pivoted, the wiper blade 16 sweeps over the area outlined in dashed lines, but this results in a slight inclination of the wiper blade 16, so that in the end position it extends along the edges of the window. The wiper arm 29 can be moved from the approximately middle working position into at least one rest position, which is shown in Fig. 2 and in which the wiper blade 16 lies along the lower edge of the window without twisting relative to the wiper arm 29. A pivot drive 5 is arranged fixed to the vehicle.

According to Fig. 2, an off-center arrangement of the windshield wiper system serves to reach the rest position in the case of a windshield 32 with a greater height without the wiper blade 16 protruding to the side. The entire surface of the windshield 32 is covered by different wiper arm extensions in the two edge positions, with the rest position, which can be reached via an actuator 19, being on the driver's side. As a result, when the windshield wiper is switched on, the part of the window on the driver's side is already covered by pivoting it up to the approximately middle working position.

Fig. 3 shows an arrangement in which the two symmetrical edge positions of normal operation and two asymmetrical edge positions of operation at high vehicle speed and heavy rain are shown, in which the wiping field is reduced by relocating the point of action of the swivel drive 5.

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Structural details of two embodiments of windshield wipers according to the invention are shown in Figs. 4 to 15. In the first embodiment according to Figs. 4 to 11, which is arranged on the motor vehicle, for example, as shown in Fig. 2, the bearing housing 30 is pivotally mounted in a mounting bracket 34 fixed to the vehicle, which defines a bearing axis 2. The mounting bracket 34 supports an axle bolt 20, to which a support body 21 is fixed in a rotationally fixed manner by means of a split pin 78. The support body 21 is connected via a link 25 to an actuator 19 (Figs. 2, 5), which pivots the support body 21 about the bearing axis 2 between the positions shown in dashed lines in Fig. 2.

The swivel drive 5 is arranged on the support body 21, the output of which is formed by a hollow shaft 3 located in the swivel axis 7, which is rotatably mounted on the axle bolt 20. If the actuator 19 is stationary, the swivel drive 5 is held fixed to the vehicle. The bearing axis 2 and the swivel axis 7 are thus coaxial.

The hollow shaft 3 and the axle bolt 20 protrude outwards through the body of the motor vehicle 1 (Fig. 5), where the bearing housing 30 is fixed to the hollow shaft 3 in a rotationally fixed manner, in which the axle bolt 20 ends and the control gear 4 is arranged. A bearing part 26 is fixed to the axle bolt 20, in which two cable reels 9, 10 are rotatably mounted, which are provided with meshing spur gears 14, 15. A gear 13 of a gear 11 is provided on the shaft of the cable reel 9 and the spur gear 14, which comprises a pinion 12, which engages in a control pin 40 having a toothing. The control pin 40 is arranged displaceably on the bearing part 26 and is located on the

Bearing housing 30 formed control cam 42 of the scanning element 6. When the actuator is at a standstill, the bearing part 26 together with the control pin 40, the cable spools 9, 10 and the gear 11 thus form a vehicle-fixed control element 41 of the control gear 4 for the wiper arm 29 containing the scanning element 6 and the control cam 42, which consists of at least two parts 27, 28.

The parts 27 and 28 of the wiper arm 29 are telescopically movable profiles, possibly curved in the longitudinal direction, which may contain a central part 18 and between which one or two roller bearing cages are arranged. The end part 28 of the wiper arm 29 carries a rotary bearing 63 for the rotary drive 50 of the wiper blade 16. A rotary disk 17 carrying the wiper blade 16 is mounted in the rotary bearing 63. The ends of a cable 8 are wound on the two cable spools 9, 10, which is connected to the rotary disk 17 mounted in the rotary bearing 63 and can consist of one continuous cable or two individual cables. The cable 8 can be attached to the rotary disk 17, or a positive connection can also be formed if thickened sections of the cable 8 engage in recesses in the rotary disk 17. For the spring loading of the control pin 40, a coil spring 37 is provided in the wiper arm 29 that pushes out the part 28. The wiper arm 29 is surrounded by a protective bellows 23 that may be filled with lubricant. When the bearing housing 30 is pivoted, the displacement of the control pin 40 thus causes a change in the length of the wiper arm 29 that is pushed outwards by the coil spring 37, with a simultaneous and equal change in the length of the two cables of the cable.

8, wherein the essentially parallel cables form the rotary drive 50 of the wiper blade 16.

The rotation of the wiper blade 16 relative to the wiper arm 29 takes place in parallel when the diameter of the turntable 17 corresponds to the diameter of the control element 41. As can be seen from Fig. 11, the total diameter of the control element 41 is slightly larger than the diameter of the turntable 17, with the cable 8 being guided over the rollers 33, so that the angle of rotation ß of the turntable 17 is slightly larger than the swivel angle α from the central position. This leads to a deviation of the wiper blade 16 from its parallel position to the width (height) of the windshield 32 and thus to a trapezoidal wiping surface. Adaptation to different windshields 32 can be carried out very easily by inserting turntables 17 with different diameters. According to Fig. 7 and 11, the wiper arm 29 has its shortest length in a middle working position and a wiper blade 16 extending approximately parallel to it. If the swivel drive 5, which locks the rotary drive 50 of the wiper blade 16, is now stopped and the actuator 19 is actuated, the wiper arm 29 including the swivel drive 5 can be swiveled without changing length about the bearing axis 2 coaxial with the swivel axis 7 from this approximately central position into a rest position on the driver's side, in which it lies parallel to the lower edge of the window and is possibly sunk into a recess in the motor vehicle.

As can be seen from Fig. 8 and 10, in this embodiment the part of the wiper arm 29 adjoining the bearing housing 30 has a transverse axis 22 which

outside the longitudinal center plane, so that the wiper blade 16 is pressed against the windshield 32 by the cable 8 tensioned by the coil spring 37. Furthermore, it is also possible for a coil spring to act on the control element 41 eccentrically to the pivot axis 7, so that the pivoting of the wiper arm 29 increases the spring tension and thus the contact pressure of the wiper blade 16.

As shown in Fig. 2, the wiper arm 29 can rest in the rest position on a bracket 24 or the like provided with an inclined run-on surface, so that the wiper blade 16 is protected.

When the windshield wiper system is switched on, the support body 21 is first pivoted from the rest position to the working position by means of the actuator 19, whereby the driver-side part of the windshield 32 is swept in a circular arc in accordance with a conventional wiper system, and then the actuator 19 is switched off and the swivel drive 5 is switched on. By selecting the asymmetrical arrangement shown in Fig. 2 below the windshield 32, the wiper arm 29 can be moved to the rest position regardless of the length-width (height) ratio of the windshield 32 and at the same time a lower wiper blade speed can be achieved on the driver side than on the passenger side. The actuator 19 can, for example, comprise a servo piston actuated by the engine vacuum, an electric motor, an electromagnet, etc.

In the second embodiment according to Fig. 12 to 15, which is arranged on the motor vehicle 1, for example according to Fig. 1 or 3, the bearing housing 30 is arranged so as to be pivotable about a bearing axis 2 fixed to the vehicle and has

a hinge pin 35, which is engaged by a link of the swivel drive 5, which is fixed to the vehicle in this embodiment, whereby the changeover device is formed within the bearing housing 30. In this embodiment, the control element 41 of the control gear 4 is arranged to be rotatable about the bearing axis 2, whereby the pin 79 defining the bearing axis 2 has a radial bore in which a first locking pin 60 is slidably acted upon by a spring 70. The control element 41 has an extension 76 in which an opening 62 is formed, into which the locking pin 60 is pressed by the spring 70 (Fig. 12). In this position, the control element 41 is held fixed to the vehicle, so that when the bearing housing 30 is pivoted about the pivot axis 7, which is coaxial with the bearing axis 2, the control gear 4 is effective for changing the length of the wiper arm and rotating the wiper blade 16 via the pivot drive engaging the joint bolt 35. The actuator 19 is arranged on the bearing housing 30 and in this embodiment is formed in particular by an electric motor with a threaded spindle 66, which passes through a carriage 75, which can be moved in a guide 74. The threaded bolt 35 for the engagement of the pivot drive 5 and a second locking pin 61 are provided on the carriage 75, which, together with the first locking pin 60, belongs to the locking device 51. If the actuator 19 is operated so that the slide 75 moves in the direction of the arrow shown in Fig. 13, the second locking pin 61 enters the opening 62 of the extension 76 of the control element 41 in the middle working position and displaces the first locking pin 60. As a result, the control element 41 is locked securely to the wiper arm (Fig. 13) and the control gear is put out of operation. As this means that the point of action of the swivel arm to

Bearing axis 2 is approached, the swivel angle is increased from the middle working position so that the wiper arm 29 is lower in the rest position. The carriage 75 can be moved further away from the common bearing/swiping axis 2,7 from the position shown in Fig. 12 with the help of the actuator 19, which results in a reduction in the wiper speed and a reduction in the size of the wiper field (Fig. 3). This can be particularly important for high driving speeds in order to ensure the perfect function of the windshield wiper system.

Claims (11)

Protection claims: 1. Windscreen wiper system, in particular for passenger cars, with a swivel drive (5) having a wiper arm (29) which has a bearing housing (30) which can be pivoted about a pivot axis (7) and at the free end a pivot bearing (63) for a wiper blade (16) which can be guided essentially parallel over the window (32), and which can be pivoted into a rest position in the region of the lower edge of the window about a bearing axis (2), the wiper blade (16) being approximately parallel to the wiper arm (29) both in the rest position and in an approximately middle working position, and with a control gear (4) assigned to the pivot drive (5) in the bearing housing (30), which has a control element (41) which is fixed to the vehicle during the parallel guidance of the wiper blade (16) and a sensing element (6) which interacts with the latter and is fixed to the wiper arm and which is deactivated during the pivoting into the rest position, with a changeover device for changing between the in-function state and the inoperative state of the control gear (4) in the approximately middle working position, and with an actuator (19), characterized in that the pivot axis (7) and the bearing axis (2) are coaxial, and the pivot angle of the wiper arm (29), in each case starting from the approximately middle working position, is greater for pivoting into the rest position than for the wiping movement in the same direction. 2. Windscreen wiper system according to claim 1, characterized in that by means of the actuator (19) a hinge pin (35) protruding from the bearing housing (30), to which the swivel drive (5) is hinged, is displaceable radially to the bearing/swivel axis (2,7).
5 3. Windscreen wiper system according to claim 2, characterized in that the actuator (19) and the changeover device (51) are arranged in the bearing housing (30). 4. Windscreen wiper system according to claim 3, characterized in that the changeover device (51) comprises two mutually abutting locking pins (60, 61) that can be moved together perpendicular to the bearing/pivot axis (2, 7), the first (60) of which is arranged in a radial bore in a spring-loaded manner, and the second (61) of which is provided with the hinge pin (35) and can be moved in the bearing housing (30), the control element (41) having an opening (62) into which one of the two locking pins (60, 61) engages. 5. Windscreen wiper system according to claim 1, characterized in that the actuator (19) is assigned a switching element which stops the swivel drive (5) in the approximately middle working position and the swivel drive (5) is provided on a support body (21) which can be swiveled through a larger angle by means of the actuator (19) and which is rigidly connected to the control element (41). 6. Windscreen wiper system according to claim 5, characterized in that a hollow shaft (3) is formed in the bearing/pivot axis (2, 7) which connects the support body (21) with the control element (41) connecting axle bolt (20) which is pivotably mounted in a vehicle-fixed bearing (34) about the bearing/pivot axis (2,7). 7. Windscreen wiper system according to one of claims 1 to 6, characterized in that a spring-loaded control pin (40) is displaceably mounted in the control element (41) and the scanning element (6) is formed by a control cam (42) formed in the bearing housing (30) which rests on the control pin (40). 8. Windscreen wiper system according to one of claims 1 to 7, characterized in that the wiper arm (29) consists of at least two parts (27, 18, 28) which can be telescopically moved into one another and two cable spools (9, 10) are mounted on the control element (41) so as to rotate in opposite directions via a toothing (14, 15), whereby the parallel guide of the wiper blade (16) comprises a cable pull (8) which is connected on the one hand to a turntable (17) carrying the wiper blade (16) and on the other hand is wound up on the cable spools (9, 10) in an extendable manner. 9. Windscreen wiper system according to claim 8, characterized in that the rotating disk (17) of the wiper blade (16) has a toothing (67) into which a drive worm (68) driven by the cable (8) engages, the standstill of which blocks the rotation of the wiper blade (16). 10. Windscreen wiper system according to claim 8 or 9, characterized in that in the part (27) of the Wiper arm (29) a transverse axis (22) is provided on the side of the cable (8) facing away from the wiper blade (16), on which the remaining part of the wiper arm (29) is pivotably mounted. 5 11. Windscreen wiper system according to one of claims 1 to 10, characterized in that the wiper arm (29) is mounted on the bearing housing (30) so as to be pivotable about a transverse axis and is acted upon by a helical spring which presses the wiper blade (16) against the windscreen and which acts on the wiper arm (29) on the one hand and on the control element (41) on the other hand eccentrically to the bearing/pivot axis (2,7). · t ·