US 4,878,398 AGranted

Driving device for window wiper of motor vehicles

AssigneeRobert Bosch GmbH

InventorLaurent Heinrich

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Abstract

The driving mechanism for a wiper of a motor vehicle includes a reversible drive shaft, a two part crank whose one part is secured to the drive shaft and whose other part is linked to the wiper to oscillate the same when the drive shaft rotates in one direction. To displace the wiper into rest position outside its wiping field when the wiping operation is switched off, there is provided a control plate rotatable about the drive shaft and supporting a swing lever provided with a lock pawl. The drive shaft passes through a cylindrical support fixed to the frame of the motor vehicle and being provided on its jacket with an indentation for receiving the lock pawl. The control plate and the first crank part are provided respectively with guiding cams cooperating with cam followers provided on the swing lever and on the second crank part to bring the lock pawl into engagement with the indentation when the drive shaft reverses its direction and to displace a crank pin formed on the second crank part radially outwardly with respect to its orbiting circular path when the drive shaft rotates in the one direction for normal wiping operation.

A driving mechanism for a window wiper of a motor vehicle, comprising a cylindrical support fixed to a frame of the motor vehicle and having an indentation in its jacket;

a reversible drive shaft arranged for rotation coaxially with said cylindrical support;
a crank assembled of two crank plates hinged one to the other;
one of said crank plates being secured to said reversible drive shaft and having a first S-shaped cam, and the other crank plate being provided with a crank pin and an oppositely directed first cam follower;
a coupling rod hinged at one end thereof to said crank pin and at the other end thereof to a rocking lever for oscillating a wiper blade in a wiping field when the drive shaft rotates in one direction;
a control plate supported for rotation about said drive shaft and having a second S-shaped cam cooperating with said first cam follower;
means for locking said control plate in a fixed position relative to said cylindrical support when said drive shaft rotates in a reverse direction;
a lock pawl pivotably mounted on said control plate and having a second cam follower cooperating with said first S-shaped cam;
said first S-shaped cam having one cam section extending concentrically with said drive shaft to guide said lock pawl in engagement with said indentation when said drive shaft rotates in the reverse direction, and another cam section extending in a tangential direction away from said cylindrical support to guide said lock pawl out of engagement with said indentation when said drive shaft rotates in said one direction;
and said second S-shaped cam having one cam section extending concentrically with said drive shaft to guide said crank pin on a circular orbiting path when said drive shaft rotates in the one direction, and another cam section directed outwardly away from said orbiting path to guide via said crank pin said wiper blade into a rest position outside said wiping field when the drive shaft rotates in the reverse direction.

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Abstract

Claims10