| 摘要 |
A variable length crank arm in a windshield wiper system provides a depressed park position for an associated wiper blade when the direction of rotation of a drive motor is reversed. The crank arm relies on an eccentric driver to vary its length and between a first length a longer second length. When the eccentric driver is rotated in a first direction to wipe the windshield, a spring loaded pin keeps the eccentric driver rotatably fixed to an output arm with the crank arm consequently at the first length. The spring loaded pin also engages a cam slot in a cam plate, the cam plate rotating freely with the output arm and the eccentric driver in the first direction. To move the blade to the depressed park position, the direction of rotation of the drive motor is reversed. This causes the cam plate to become rotatably stopped, with the now stationary cam slot forcing the pin out of engagement with the output arm. Continued reverse motor rotation rotates the eccentric driver relative to the output arm increasing the length of the crank arm, moving the blade to the depressed park position. |
