Abstract: As to a reciprocating stroke wiper system for motor vehicles with a piston movably guided in a housing a projecting arm unrotatably fixed to the piston and comprising a guiding fork is provided as a protection against twisting, which projecting arm is guided along a guiding element fixed to the housing. According to the invention a rod with circular cross-section is used as a guiding element, which rod is arranged at an angle towards the axis of the piston so that the guiding areas of the guiding rod and of the guiding fork touching each other are displaced crosswise to them during the motion so that the effective guiding area is enlarged and thus wear is reduced.

Abstract: A windshield washing system for motor vehicles is described in which a non-return valve is installed into the feed pipe, which non-return valve, for ensuring a quick response from the washing system, prevents the feed pipe from emptying, while the pump is switched off. According to the invention a bypass switchable via a valve runs parallelly to this non-return valve, which bypass is opened in winter, i.e. in low outdoor temperatures, but is closed in summer. Consequently during winter mode of operation the feed pipe is emptied. Thus the washing liquid is prevented from freezing.