Title of Invention

WIPER SYSTEM FOR VEHICLES AND METHOD FOR OPERATING A WIPER LEVER LINKAGE

Abstract

A wiper system (1) for vehicles, having at least one wiper lever linkage (3) which has at least one wiper arm (35), and a method for operating the wiper lever linkage (3) are proposed. The said wiper lever linkage has a first pivoting lever (5), which can be coupled in a rotationally fixed manner to a positionally fixed, first spindle (21), and a second pivoting lever (7), which can be coupled in a rotationally fixed manner to a positionally fixed, second spindle (29), which pivoting levers are connected in an articulated manner to a coupling element (9). The wiper system (1) is distinguished in that the coupling element (9) is of multipart design and has a first coupling part (11) and a second coupling part (13) which are connected to one another with the aid of a joint (15).

Full Text

Wiper system for vehicles and method for operating a wiper lever linkage Prior art The invention relates to a wiper system for vehicles in accordance with the precharacterizing clause of Claim 1 and to a method for operating a wiper lever linkage of a wiper system for vehicles according to Claim 10. A known wiper system has a pivoting lever which can pivot freely about a spindle arranged in a positionally fixed manner and to which a wiper arm which is provided with a wiper element is fastened. This design causes the wiper arm to follow a circular path, which results only in a small wiping field which in many cases does not satisfy the requirements. In addition, a wiper system is known which has a four-joint wiper lever linkage which comprises first and second pivoting levers which are in each case coupled in a rotationally fixed manner to a spindle arranged in a positionally fixed manner and are connected in an articulated manner to a coupling element. Fastened to the coupling element is a wiper arm which is provided with a wiper element and, during pivoting of the pivoting levers, carries out a lifting and pivoting movement, which leads to an enlargement of the wiping field. A disadvantage of the known wiper system is the large structural space which is required for the wiper lever linkage which has to be provided in the region of the vehicle front end for the wiper system to be used for cleaning a windscreen of a motor vehicle. However, there is only little space in the front end region of the motor vehicle and this will become even smaller in future vehicles, since it has been shown that the ratio of the length of the interior to the overall length of the motor vehicle is becoming ever more large. In addition, it has been shown that the wiping field of the four-joint wiper lever linkage is not of a sufficient size in order to be able to obey the legal requirements in the case of large screen surfaces which are planned in particular in future vehicles, or to satisfy the increasing requirements for comfort and safety. Advantages of the invention The wiper system according to the invention having the features of Claim 1 has, in contrast, the advantage that by using the wiper lever linkage in the same structural space a considerably greater lift and therefore also a larger wiping field can be realized than in the case of the known wiper system having the four-joint wiper lever linkage. It is, of course, also possible to realize a wiper lever linkage which, in the case of a wiping field which is at least essentially the same size and a lift which is the same size as is also possible in the case of the known four-joint wiper lever linkage, can be designed in such a manner that it has smaller structural space. In order to realize a large wiping field with a compact construction of the wiper lever linkage, in the case of the wiper system according to the invention provision is made for the coupling element to be of multipart design and to have a first coupling part and a second coupling part which are coupled to each other with the aid of a joint. As a result, a five-joint wiper lever linkage is realized in which exact control of the lift is possible. In a particularly advantageous exemplary embodiment of the wiper system, the wiper lever linkage is assigned a driving device which has first and second driving cranks of which the first driving crank is coupled in a rotationally fixed manner to the first spindle, to which the first pivoting lever is also fastened, and the second driving crank is coupled in a rotationally fixed manner to the second spindle, on which the second pivoting lever is held. The first and second spindles are therefore each acted upon by a driving or braking torque which is transferred into the wiper lever linkage via the pivoting levers. In an advantageous design variant, the first and second driving cranks are connected in an articulated manner to each other with the aid of a coupling link. The movements of the first and second driving cranks, and therefore also of the first and second pivoting levers, are thereby dependent on one another, as a result of which the degree of freedom of the wiper lever linkage formed between the first coupling part and the second coupling part is equalized or compensated by the additional joint. In order to coordinate the movements of the two driving cranks with each other, in another design variant, the first and second driving cranks are respectively connected in an articulated manner to a motor crank, the motor cranks in turn being coupled to each other in such a manner that their oscillating movements are coordinated exactly with one another. In both design variants for controlling the pivoting movement of the driving cranks, and therefore also that of the first and second pivoting levers, the pivoting angle of the second driving crank can be adjusted freely independently of the multipart coupling element connecting the pivoting levers to each other, since the first and second coupling parts of the coupling element are connected to one another in an articulated manner and therefore an additional degree of freedom of the joint pentagon is realized. Adjustment of the pivoting angle of the second driving crank is possible, for example, by a change in length of the coupling link. Further advantageous refinements of the wiper system emerge from the other subclaims. The subject matter of the invention also relates to a method for operating a wiper lever linkage of a wiper system for vehicles having the features of Claim 10, in which provision is made for the first and second driving cranks to be pivoted during a wiping cycle in the same direction from a starting position of the wiper lever linkage to an extended position in which the coupling link, which may, for example, be of rod-shaped design, and the first driving crank are aligned with each other. In the further course of the wiping cycle, in which the wiper lever linkage is displaced from the extended position into a reversing position, the first driving crank is pivoted further in the same direction and the second driving crank is pivoted further in an opposed direction- In order to optimize the sequence of movement of the wiper lever linkage, the latter is designed in such a manner that during a wiping cycle the first driving crank has two turning positions and the second driving crank has three turning positions in which a reversal of the pivoting direction takes place in each case. Further advantageous embodiments of the method emerge from the other subclaims. Drawing The invention is explained in greater detail below with reference to the drawing, in which: Figure 1 shows a schematic diagram of part of a first exemplary embodiment of the wiper system according to the invention; Figure 2 shows a schematic diagram of a first exemplary embodiment of a driving device for a wiper lever linkage; Figure 3 shows a schematic diagram of a second exemplary embodiment of a driving device; Figures 4 A to 4C show an exemplary embodiment of the wiper lever linkage in three positions; Figure 5 shows a diagram revealing the lift profile of the wiper lever linkage during a wiping cycle; Figures 6A and 6B show a plurality of wiping fields which can be realized with the wiper lever linkages-Figure 7 shows pivoting ranges of driving cranks and a coupling link connected to the latter in an articulated manner, and Figure 8 shows, respectively, the pivoting range of a first driving crank and of a second driving crank of a known four-joint wiper lever linkage. Description of the exemplary embodiments The wiper system 1 which is described below can be used universally, for example for motor vehicles (passenger vehicle, lorry, bus), rail vehicles or water craft. The starting point below, purely by way of example, is a wiper system for a motor vehicle. Figure 1 shows, in a schematic view, part of a first exemplary embodiment of the wiper system 1 which comprises a wiper lever linkage 3 which has a first pivoting lever 5, a second pivoting lever 7 and a coupling element 9. The coupling element 9 is of multipart design and has a first coupling part 11 and a second coupling part 13 which are coupled to each other with the aid of a joint 15. The second coupling part 13 is considerably longer, in this exemplary embodiment several times longer, than the first coupling part 11, The first coupling part 11 and the first pivoting lever 5 are coupled to each other in an articulated manner via a joint 17, and the second coupling part 13 and the second pivoting lever 7 are coupled to each other in an articulated manner with the aid of a joint 19. At its end region which is remote from the first coupling part 11, the first pivoting lever 5 is coupled in a rotationally fixed manner in a rotationally fixed manner [sic] to a first spindle 21 of a first bearing 23, with the result that when the first spindle 21 is pivoted about its longitudinal central axis, which runs perpendicularly with respect to the image plane of Figure 1, the first pivoting lever 5 is correspondingly pivoted at the same time. A second bearing 25 is provided at a distance from the first bearing 23 and, like the first bearing 23, is arranged in a positionally fixed manner on a base 27 (illustrated by a dash-dotted line). The second bearing 25 has a second spindle 29 which is mounted such that it can pivot about its longitudinal central axis and to which the second pivoting lever 7 is connected in a rotationally fixed manner. The spindles 21, 29 are therefore, as it were, further joints 31, 33 of the wiper lever linkage 3, which has a total of five joints. The wiper lever linkage 3 has a wiper arm 35 which is fastened to the second coupling part 13 of the coupling element 9. The angle a between the wiper arm 35, which has an angled base body, and the second coupling part 13 is therefore also constant during a lifting and pivoting movement of the wiper lever linkage 3 and is about 55° here. Attached to the wiper arm 35 is a wiper element (not illustrated in Figure 1) which may, for example, have a rubber lip and which can be placed in a known manner against a screen of the vehicle and is correspondingly displaced during a lifting and pivoting movement of the wiper lever linkage 3. In the process, a wiping field 37 is wiped whose shape, arrangement and size is determined by the lifting and pivoting movement of the wiper lever linkage 3, Only the lower edge 39 of the wiping field 37 can be seen in the illustration according to Figure 1, the said edge having a curved profile, in which case in addition to curved sections there are also linear sections in which the wiper arm 35 - as seen in the vertical direction - is raised or. in the case of a reversal of the pivoting direction of the wiper arm 35, is lowered or is displaced essentially in the horizontal direction. The ratio of the length of the first and second coupling parts 11, 13 differs considerably. The first coupling part 11 which produces the lift has a relatively small length so that its movement causes a rotational movement which is as small as possible to be transferred to the long, second coupling part 13, which otherwise could result in interference in the sequence of movement of the wiper lever linkage 3, The wiper system 1 furthermore comprises a driving device 41 for the wiper lever linkage 3, with only a first driving crank 43 and a second driving crank 45 of the said driving device being illustrated in Figure 1. The first driving crank 43 is coupled in a rotationally fixed manner to the first spindle 21 to which the first pivoting lever 5 is also connected. The arrangement of the first driving crank 43 and the first pivoting lever 5 on the spindle 21 is selected in such a manner that they are arranged opposite each other in a pivoted position, in which case, because of the rotationally fixed connection between the first spindle 21 and the driving crank 4 3 and the pivoting lever 5, the angle P between these parts is constant during a lifting and pivoting movement of the wiper lever linkage 3. The second driving crank 45 is arranged on the second spindle 2 9 in a position whose angle of rotation is offset with respect to the second pivoting lever 7, and is connected in a rotationally fixed manner to the said spindle. This design means that the angle y between the driving crank 45 and pivoting lever 7 is also constant during displacement of the wiper lever linkage 3. The first and second driving cranks 43, 45 are connected to each other with the aid of a coupling link 47 which is connected in an articulated manner to the first driving crank 4 3 via a joint 4 9 [lacuna] to the second driving crank 45 [lacuna] a further joint 51. The coupling of the two driving cranks 43, 45 to each other means that a precise control of the pivoting movements of the pivoting levers 5, 7 can be realized in a simple manner, which is discussed in greater detail below. Figure 1 illustrates by means of a dashed line a known four-joint wiper lever linkage which likewise has first and second pivoting levers which are connected to each other via a rigid, one-piece coupling element, the coupling element being connected to the pivoting levers via a respective joint. A wiper arm having a wiper element is likewise fitted to the four-joint wiper lever linkage and during a lifting and pivoting movement of the wiper lever linkage traverses a wiping field whose lower edge 53 is illustrated in Figure 1 by a dashed line. A comparison shows that the wiping field of the five-joint wiper lever linkage 3 and that of the four-joint wiper lever linkage are essentially identical, that is to say the height and the width of the wiping fields are approximately the same size. However, the wiper lever linkage 3 according to the invention requires a considerably smaller constructional space than the conventional four-joint wiper lever linkage, which is advantageous particularly when the wiper lever linkage 3 is arranged in the front end region of a motor vehicle, since there is only a small space there for accommodating the wiper system 1, One reason for the compact construction of the wiper lever linkage 3 is, in particular, the relatively small distance of the first bearing 23 from the second bearing 25 for the wiper lever linkage 3, which is possible only because of the multipart design of the coupling element 9 _ An exemplary embodiment of the driving device 41 for the driving cranks 43, 45 is respectively explained in greater detail below with reference to Figures 2 and 3. Parts which have already been described with reference to the wiper system 1 illustrated in Figure 1 are provided with the same reference symbols, so that reference is made in this respect to the description for Figure 1. The driving device 41 has a drive shaft 55 which is arranged in a positionally fixed manner at a distance from the bearings 23, 25 of the wiper lever linkage 3, preferably towards the vehicle centre, and can be acted upon by a driving or braking torque and can rotate about its longitudinal central axis, which runs perpendicularly with respect to the image plane of Figure 2. Fastened to the drive shaft 55 is a transfer lever 57 which rotates jointly with the drive shaft as the latter rotates, The driving device 41, which is designed as a series drive in the case of the exemplary embodiment illustrated in Figure 2, also has a motor crank 59 which is connected in an articulated manner to the transfer lever 57 via a joint 61 and, at its other end region, to the first driving crank 21 via a further joint 63, When the drive shaft 55 rotates, the motor crank 59 is displaced to and fro in the direction of a double arrow 65. Because of the articulated coupling of the motor crank 59 to the first driving crank 43, when there is an oscillating movement of the motor crank 59 the driving crank 43 and, because of its coupling to the second driving crank 45 via the coupling link 47, also the second driving crank 45 are jointly pivoted about the first spindle 21 and the second spindle 29, respectively. The two spindles 21, 29 are therefore driven• In the case of the exemplary embodiment of the driving device 41 illustrated in Figure 3^ a direct drive for the spindles 21, 29 is realized. The driving cranks 43, 45 are not connected to each other here via a coupling link 47, which has been described with reference to Figures 1 and 2, but via motor cranks 59 and 67 of which the motor crank 59 is connected in an articulated manner to the first driving crank 43 by means of the joint 63 and the other motor crank 67 is connected in an articulated manner to the second driving crank 45 via the joint 51. At their end regions which are remote from the driving cranks, the motor cranks 59, 67 are in each case connected to each other in an articulated manner via a joint 69 by a transfer lever 57, which is formed by a triangular plate 71, where the transfer lever 57 is connected in a rotationally fixed manner to the drive shaft 55. When the drive shaft 55 is rotated about its longitudinal central axis, the motor cranks 59, 67 are displaced in the direction of the arrows 65 in an oscillating manner essentially in a horizontal direction, as a result of which the driving cranks 43, 45, and therefore the spindles 21, 29 and the first and second pivoting levers 5, 7 which are connected to the spindles, are pivoted in a corresponding direction. In an advantageous exemplary embodiment, the joints 17, 19 between the pivoting levers 5, 7 and the coupling element 9 and the additional joint 15 between the coupling parts 11, 13 and, preferably, the joints 51, 61, 63, 69 of the driving device 41 are designed as cylindrical joints whose rotational axes run parallel to one another and preferably parallel to the first and second spindles 21, 29. In an advantageous exemplary embodiment, the joints of the wiper lever linkage 3 are designed as releasable, torque-transmitting shaft-hub connections. The cylindrical joints have great rigidity. Of course, it is also possible for at least some of the joints to be formed by ball and socket joints. The movement of the wiper lever linkage 3 of the wiper system 1 illustrated in Figure 1 is explained below in greater detail with reference to Figures 4A to 4C, the said wiper lever linkage being illustrated in a different position in each of the figures. It can be seen that the wiper lever linkage 3 is driven by a driving device 41 which has been described with reference to Figure 3. In the position illustrated in Figure 4A, the wiper lever linkage 3 is in a starting position in which the wiper arm 35 is arranged outside the wiping field 37, preferably essentially parallel to an imaginary horizontal line. With the aid of the driving device 41 the first and second driving cranks 43, 45, which are connected to each other via the coupling link 47, are pivoted anticlockwise into their position which is illustrated in Figure 4B, as indicated by arrows 73, 75• In the position illustrated in Figure 4B, the wiper lever linkage 3 is in an extended position in which the coupling link 47 and the first driving crank 43 are aligned with each other. It can be seen that in this functional position the first and second coupling parts 11, 13 are not in an extended position, but are inclined with respect to each other, with the result that wedging of the wiper lever linkage 3 can be virtually eliminated. In the extended position of the wiper lever linkage 3 the wiper arm 35 is arranged in a position in which it has reached its maximum lift. In the extended position of the wiper lever linkage 3 a reversal in the pivoting direction of the second driving crank now takes place, that is to say, the second driving crank 4 5 is now pivoted in an opposed direction, i.e. in the clockwise direction, whereas the first driving crank 43 is further pivoted anticlockwise (arrow 73) . The driving cranks 4 3, 4 5 therefore now have opposed pivoting directions until the wiper lever linkage 3 is displaced into the reversing position which is illustrated in Figure 4C and in which a half wiping cycle is at an end. In the reversing position of the wiper lever linkage 3 the wiper arm 35 is arranged at a small distance from an A-pillar of ■ the vehicle. In order to pivot the wiper arm 35 back into its starting position according to Figure 4A, the motor crank 59, which is illustrated in Figure 2, is now displaced to the right by rotation of the drive shaft 55 (Figure 3) in the same direction. In the process, the first driving crank 43 is pivoted in the clockwise direction and the second driving crank 45 is pivoted anticlockwise until they again reach the extended position which is illustrated in Figure 4B and in which the coupling link 4 7 of the [sic] driving crank 43 are again in alignment with each other. In the extended position a reversal of the direction of rotation of the second driving crank 43 takes place again and this driving crank is now pivoted further in the clockwise direction together with the first driving crank 43 until they reach the reversing position illustrated in Figure 4A. A complete wiping cycle is thereby concluded. Figure 5 shows a diagram in which the lift H of a wiper lever linkage of the type under discussion here is plotted on its Y-axis and the pivoting angle co of the first driving crank 43 is plotted on its X-axis. A curve 77 illustrated in Figure 5 shows the lift profile of the five-joint wiper lever linkage 3 which has been described with reference to the preceding figures and has the form of a parabola, the turning point of the parabola lying approximately at co = 70^^, which corresponds to the extended position of the wiper lever linkage 3 in Figure 4B. A curve 7 9 which shows the lift profile of a conventional 4-joint wiper lever linkage is illustrated by a dashed line. When a comparison is made, it is clear that the maximum lift of the four-joint wiper lever linkage is considerably smaller than that of the wiper lever linkage 3 according to the invention in which case the differential lift AH is realized by the two-part coupling element 9 whose lift profile is illustrated by a curve 81. As can be seen from Figure 5, the total lift of the five-joint wiper lever linkage 3 is therefore formed from two partial lifts. The first partial lift is formed within the coupling element 9, whereas the other partial lift takes place between the frame-fixed pivot point (spindle 21) of the driving crank 4 3 and the coupling bearing point (joint 51) of the second driving crank 45, The sum of the two partial lifts results in the total lift of the five-joint wiper lever linkage 3. The kinematic configuration of the wiper lever linkage 3 is preferably selected in such a manner that the maximum of the two partial lifts takes place simultaneously and the greatest possible total lift is therefore achieved. It is advantageous, furthermore, that the position of the maximum lift of the wiper lever linkage 3 can be selected relatively freely, since the arrangement of the respective position of the maximum lift of the two partial lifts offers a number of combination options by lever lengths or the positions of the joint pivot points being varied accordingly. Figure 6A illustrates an exemplary embodiment of the wiper lever linkage 3 with which a wiping field 37 can be realized whose edge 39 is illustrated by a solid line. Also illustrated is the edge 83 of a partially circular wiping field of a known wiper lever linkage which has an uncontrolled lift, that is to say, its wiper arm is pivoted merely about a positionally fixed axis. The edge 83 therefore exhibits a circular shape with the centre point of the pivoting axis of the wiper arm. Figure 6A furthermore illustrates a further wiping field which has an edge 85 and can be realized by a known four^-joint wiper lever linkage, as has been described with reference to Figure 1, It can be seen that the lift of the wiper lever linkage 3 according to the invention is considerably larger than the lift which can be realized by the known four-joint wiper lever linkage - with the constructional size preferably .being essentially the same. The large wiping field signifies greater safety and comfort for a vehicle occupant. Figure 6B illustrates further wiping fields 37 having the edges 3 9 and 39' which can be realized by the wiper lever linkage 3 according to the invention. In order to determine the geometry of the wiping field 37, the lengths of the pivoting levers 5, 7 and those of the coupling element 9 and coupling parts 11, 13 and of the first and second driving cranks 43, 45 only need to be set correspondingly or matched to one another. In addition, the geometry of the wiping field can likewise be influenced by a mutually coordinated sequence of movement of the first and second driving cranks 43, 45. Figure 7 shows part of an exemplary embodiment of the wiper lever linkage 3 and the driving device 41. In detail, the pivoting range 87 of the first pivoting lever 5, the pivoting range 8 9 of the second pivoting lever 7, the pivoting range 91 of the first driving crank 43, the pivoting range 93 of the second driving crank 45 and the pivoting range 95 of the coupling link 4 7 are illustrated. In comparison to this. Figure 8 illustrates the pivoting ranges 97 and 99 of first and second pivoting levers 101 and 103 of the known four-joint wiper lever linkage 105. The pivoting lever 101 is connected in a rotationally fixed manner to a spindle 107 of a positionally fixed bearing 109 and the second pivoting lever 103 is connected to a spindle 111 of a second bearing 113. It is clear that the pivoting range 89 of the second pivoting lever 7 of the five-joint wiper lever linkage 3 according to the invention is considerably larger than the pivoting range 99 of the second pivoting lever 103 of the known four-joint wiper lever linkage 105, while the pivoting range 87 of the first pivoting lever 5 and the pivoting range 97 of the first pivoting lever 101 are essentially the same size. In summary, it should be stressed that a considerably larger lift, and therefore an enlarged wiping field, can be realized by means of the f ive-joint wiper lever linkage 3, which has been described with reference to the preceding figures, than with the wiper lever linkages which are mentioned at the beginning and this can be achieved by means of the coupling parts 11, 13 which are connected in an articulated manner to each other and to the first and second pivoting levers 5, 7. A further advantage of the five-joint wiper lever linkage 3 resides in the fact that the joint technology and preferably at least parts of the driving device can be taken from the known four-joint wiper lever linkage. Compared to the known wiper lever linkage, the wiper lever linkage 3 has reduced transmission ratios, as a result of which the kinematic quality of the mechanism is improved and the motor starting torque required for operation (the torque to be applied to the drive shaft 55) is therefore reduced. The wiper lever linkage 3 has a simple construction, in particular since complicated cross angle mechanisms can be dispensed with. In addition, it is advantageous that the relative angles between the moving parts (first pivoting lever 5 and first coupling part 11/second pivoting lever 7 and second coupling part 13) of the five-j oint wiper lever linkage 3 are considerably smaller than in the case of a known four-joint wiper lever linkage. As a result, the joints are also subjected to less stress, and so, if appropriate, smaller joints can be used. WE CLAIM: 1. A vehicle windscreen wiper system (1) with at least one wiper arm linkage (3) having at least one wiper arm (35) comprising a first pivoting lever (5) that can be rotationally fixed to a stationary first axle (21), and a second pivoting lever (7) that can be rotationally fixed to a stationary second axle (29), said arms being hinged to a coupling element (9), said element having a multi-component design and featuring a first coupling element (11) and a second coupling element (13) which are coupled by means of a first hinge (15), the wiper arm (35) being attached to the second coupling element (13) and the first coupling element (11) being connected to the first pivoting lever (5) by means of a second hinge (17) at its end facing away from the first hinge (15), and the second coupling element (13) being connected to the second pivoting lever (7) by means of a third hinge (19) at its end facing away from the first hinge (15), characterized in that the second coupling element (13) is longer, preferably significantly longer, than the first coupling element (11), and that the first pivoting lever (5) and the second pivoting lever (7) are linked by means of a pivoting coupling device. 2. The windscreen wiper system as claimed in claim 1, comprises a drive mechanism (41) for the wiper arm linkage (3) which comprises at least one first drive crank (43) that can be rotationally fixed to the first axle (21) or the second axle (29). 3. The windscreen wiper system as claimed in any of the preceding claims, wherein the first drive crank (43) can be rotationally fixed to the first axle (21) and that the drive device (41) comprises a second drive crank (45) that can be rotationally fixed to the second axle (29), 4. The windscreen wiper system as claimed in any of the preceding claims, comprises a coupling element (47) linking the first and second drive cranks (43,45), said element being Coupled to the drive cranks (43,45) by means of a respective hinge (49, 51), also wherein at least one motor crank (59) is hinged to the first drive crank (43) or the second drive crank (45). 5. The windscreen wiper system as claimed in any of the preceding claims 1 to 3,wherein each of the first and second drive cranks (43,45) is hinged to a respective motor crank (59,67). 6. The windscreen wiper system as claimed in any of the preceding claims, wherein the motor crank (59,67) is transversally or essentially transversally displaceable with respect to the first and second axles (21,29). 7. The windscreen wiper system as claimed in any of the preceding claims, wherein the hinges (17,19) between the pivoting levers (5,7) and the coupling element (9), as well as the additional hinge (15) between the coupling parts (11,13) are in the shape of cylinder hinges whose pivoting axles run parallel to each other and preferably parallel to the first and second axles (21,29). 8. A method for operating a wiper arm linkage (3) of a vehicle windscreen wiper system (1) according to one or several of the preceding claims, which comprises at least one wiper arm (35), the system comprising a first pivoting lever (5) that can be rotationally fixed to a stationary first axle (21), a second pivoting lever (7) that can be rotationally fixed to a stationary second axle (29), a first drive crank (43) that can be rotationally fixed to a first axle (21), a second drive crank (45) that can be rotationally fixed to the second axle (29), as well as a coupling element (47) hinged to the drive cranks (43,45), the procedure comprising the following steps during one wiping cycle: pivoting both the first and second drive cranks (43,45) from an initial position of the wiper arm linkage (3) into a first direction until an extended position is reached in which the coupling element (47) and the first drive crank (43) are aligned with one another, displacing the wiper arm linkage (3) from the extended position into a reverse position by pivoting the first drive crank (43) into the first direction and the second drive crank (45) in the second direction that is opposite to the first direction, displacing the wiper arm linkage (3) from the reverse position into the extended position by pivoting the first drive crank (43) into the second direction and the second drive crank (45) into the first direction, pivoting both the first and second drive cranks (43,45) into the second direction from the extended position of the wiper arm linkage (3) into the initial position.

Documents:

in-pct-2001-857-che-abstract.pdf

in-pct-2001-857-che-claims filed.pdf

in-pct-2001-857-che-claims granted.pdf

in-pct-2001-857-che-correspondnece-others.pdf

in-pct-2001-857-che-correspondnece-po.pdf

in-pct-2001-857-che-description(complete)filed.pdf

in-pct-2001-857-che-description(complete)granted.pdf

in-pct-2001-857-che-drawings.pdf

in-pct-2001-857-che-form 1.pdf

in-pct-2001-857-che-form 26.pdf

in-pct-2001-857-che-form 3.pdf

in-pct-2001-857-che-form 5.pdf

in-pct-2001-857-che-other documents.pdf

in-pct-2001-857-che-pct.pdf