Actuating mechanism for imparting oscillatory motion to an output shaft

An acutating mechanism for driving an output shaft mounted for rotary oscillation about a fixed axis,

• the actuating mechanism comprising a housing,
• a drive shaft,
• a slidable means journalling the drive shaft for rotation about an axis parallel to the fixed axis of the output shaft,
• the slidable means comprising slide members,
• guide means supporting the slidable members on a plate portion of the housing for linear shiftable movement between a first and a second position toward or from the fixed pivot axis of the output shaft,
• linked crank means coupling the output shaft to the drive shaft constructed and arranged so that rotation of the drive shaft causes rotary oscillation of the output shaft through an arc of fixed length,
• a worm gear coupled to the drive shaft having meshing engagement with a drive worm,
• the drive worm being mounted for rotation on a worm shaft the axis of which parallels the line of movement of the slidable means,
• reversible motor means coupled to the drive worm for rotating the latter in either direction,
• the reaction force between the drive worm and the worm gear during rotation having a force component causing the slidable means to shift axially of the worm shaft toward or from the fixed pivot axis of the output shaft, depending on the direction of rotation of the reversible motor,
• the slide members and plate portion having coacting stop means limiting the movement of the slide members toward or from the fixed pivot axis of the output shaft,
• the shift of the slide means and thereby of the drive shaft causing displacement of the fixed length arc through which the output shaft is oscillatable.

A windshield wiper actuating mechanism for oscillating a windshield wiper blade supporting shaft,

• the actuating mechanism being adapted to be driven by a reversible motor means and comprising a housing,
• the motor means being coupled to a power shaft extending into the housing and carrying a drive worm,
• a worm gear carried on a drive shaft and in mesh with the drive worm,
• articulated crank and link means providing a driving connection between the drive shaft and the wiper blade supporting shaft for imparting oscillatory movement to the latter to move a wiper blade mounted thereon through a wiping pattern arc of predetermined size,
• a slide means journalling the drive means,
• and guide means supporting the slide means for shiftable movement in a direction parallel to the longitudinal axis of the power shaft between a first and a second position,
• the slide means when in the first position maintaining a drive shaft and wiper blade mounting shaft relationship in which the articulated crank and link means is adapted to drive the wiper blade over a wipe pattern of predetermined length on a windshield,
• the slide means when shifted to the second position shifting the drive shaft relative to the wiper blade shaft and causing the articulated crank and link means to displace the wipe pattern without changing the length thereof,
• the slide means position being determined by the direction of application of the reaction force between the drive worm and worm gear resulting from the direction of rotation of the rotatable motor.