Patent ID: 7458428
Filing Date: 2008-12-02
Classification: E02F

Abstract:
1. A blade lowering method for a towed scraper pulled over ground by a towing vehicle, the scraper having a front frame coupled to the towing vehicle, a rear frame, ground engaging wheels supported from the rear frame and a blade movable with respect to the front frame, the method comprising: a) sensing the ground speed of the vehicle; b) sensing a draft force applied by the scraper to the vehicle; c) with the vehicle pulling the scraper at a target ground speed with the blade positioned above a surface of the ground, automatically lowering the blade with respect to the front frame at a first rate until the blade begins to engage the surface of the ground; d) thereafter, while the vehicle continues to move forward at or near the target ground speed, lowering the blade with respect to the front frame at a second rate and for a duration related to the sensed ground speed so that lowering of the blade stops when the scraper wheels begin to enter a cut produced by the blade; e) with the blade fixed with respect to the front frame, moving the scraper forward at or near the target ground speed for a distance determined as a function of the sensed draft force; and f) thereafter raising the blade with respect to the front frame until the position of the blade relative to the front frame matches the position of the blade relative to the front frame at the end of step c).