Drive mechanism for windshield wiper systems on motor vehicles

A drive mechanism for windshield wipers on motor vehicles comprising a d.c. motor (10) which is driven in at least two different speeds of operation, which d.c. motor comprises a collector (11), a first and a second carbon brush (12, 13) resting against the collector (11) substantially diametrical to each other, and a third carbon brush (14) which, set off relative to the second carbon brush (13) at a defined angle, rests against the collector (11) on one side between the first and second carbon brush, wherein, when the d.c. motor (10) is operated with the first speed of operation (I) the first and the second carbon brush (12, 13) are connected to a voltage source (23) and, when the d.c. motor (10) is operated in the second speed of operation (II) the first and the third carbon brush (12, 14) are connected to said voltage source, and a fourth carbon brush (15) which, relative to the third carbon brush (14) rests against the collector (11) at the other side of the connecting line (31) between the first and second carbon brush (12, 13) and is connected to the voltage source (23) in parallel to and jointly with the third carbon brush (14), and

• wherein for a third speed of operation (III) there are provided two further carbon brushes (16, 17) resting against the collector (11) at opposite sides of the connecting line (31) between the first and the second carbon brush (12, 13), which carbon brushes (16, 17) are set off relative to the second carbon brush (13) to an extent which differs from that of the third and the fourth carbon brush (14, 15) and are connected in parallel and jointly to the voltage source (23).