1. IN A POWERED MOLDBOARD PLOW, A FRAME HAVING A HORIZONTAL PORTION AND A VERTICAL PORTION EXTENDING DOWNWARDLY FROM ONE END THEREOF, AN ELONGATED BAR MEMBER PIVOTALLY SECURED TO THE LOWER END OF SAID VERTICAL PORTION, SAID ELONGATED BAR PIVOTING IN A TRANSVERSE PLANE TO THE LONGITUDINAL AXIS OF SAID HORIZONTAL PORTION, A MOLDBOARD RIGIDLY SECURED TO THE LOWER END OF SAID ELONGATED BAR MEMBER, A DRIVE SHAFT ROTATABLY MOUNTED ON SAID HORIZONTAL PORTION AND CONNECTED AT ONE END TO A POWER MEANS, A ROCKER ARM PIVOTALLY CONNECTED AT THE LOWER END TO SAID MOLDBOARD, SAID ROCKER ARM PIVOTALLY MOUNTED ON SAID VERTICAL PORTION INTERMEDIATE ITS LENGTH, A RACE PIVOTALLY CONNECTED TO THE UPPER END OF SAID ROCKER ARM, AND AN ECCENTRIC DISK MOUNTED ON THE OTHER END OF SAID DRIVE SHAFT WHICH IS ROTATABLY MOUNTED IN SAID RACE.