A moldboard plow implement includes an elongated tool bar and several moldboard plow units, each plow unit including a plow bottom and a plow bottom support frame connected to the tool bar for pivotal movement about a pivot axis situated in vertical alignment with the point of the respective plow bottom. The plow units are pivotally moved in unison in response to the plowing speed to maintain the specific plow resistance constant for all tractor speeds.
Iowa State University Research Foundation, Inc.
Buchele, Wesley F.; Baldwin, William I.; Eidet, James H.; and Marley, Steven J., "Method and apparatus for controlling the approach angle of a plow unit in response to speed variations" (1979). Iowa State University Patents. 17.