Abstract: A towed scraper control system automatically lowers the scraper blade to a working position at the start of a scraping operation according to a certain method. The method includes sensing a ground speed of the vehicle and sensing a draft force applied by the scraper to the vehicle. With the vehicle pulling the scraper at or near a target ground speed over terrain with the blade positioned above a surface of the ground, the blade is automatically lowered with respect to the scraper frame at a first rate until the blade begins to engage the surface of the ground. Thereafter, while the vehicle continues to move forward at or near the target ground speed, the blade is lowered with respect to the 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 wheel begins to enter a cut produced by the blade.

Abstract: A draft force sensor is provided for a coupling member coupled between a towing vehicle and a towed earth engaging implement, such as a scraper. The draft force sensor includes first and second bores extending through the coupling member. Each bore has a horizontal axis which extends perpendicular to a main fore-and-aft axis of the coupling member. The second bore is positioned above the first bore and spaced apart from the first bore. Each of the bores is surrounded by an outer cylindrical wall. Four electrical strain gauges are spaced apart and placed on the wall of each of the bores. A center line bisects an axis line which extends between the axes of the first and second bores. The axis of each bore is spaced apart from the center line by a distance which is less than a diameter of the bores. The strain gauges are connected electrically in a circuit which generates a draft force signal in response to draft forces applied to the coupling member.