On-land plow assembly with a plurality of adjustable plow units

A plow assembly adapted to be pulled behind an agricultural implement and including a plurality of plow units each having ground engaging means capable of producing a furrow when the plow assembly is pulled along by the agricultural implement, said plow assembly comprising:

• a main frame including a generally horizontal beam inclined relative to the direction of travel of the plow assembly and having each plow unit connected thereto in spaced relation relative to each other for rotation about respective vertical axes, said main frame further including an elongated structural member connected at one end in fixed relation to said horizontal beam and connected at an opposite end to said tractor about a generally vertical spindle defining an upright pivotal axis;
• actuation means for simultaneously rotating all of the plow units about their respective vertical axes thereby adjusting the spacing between adjacent plow units within a predetermined range;
• support means for supporting a rear end of said main frame, said support means including a ground engaging steering wheel adapted to ride in a furrow provided by the rearmost plow unit;
• and
• operative means for automatically holding said steering wheel generally parallel to the furrows produced by said plow units for all settings of the spacing between said plow units within said predetermined range and for turning said steering wheel through an angle in response to and in a direction opposed to a steering angle of the implement thereby facilitating turning of the plow assembly behind the agricultural implement, said operative means including a rotatable drive arm connected to said vertical spindle and responsive to the turning angle of the agricultural implement, a driven arm carried toward a distal end of said horizontal beam for pivotal rotation about a fixed vertical axis and connected to said steering wheel, a force transfer member pivotally connected to said horizontal beam for rotation about a vertical mount arranged intermediate said drive and driven arms, a first tie rod having a first end pivotally connected to a distal end of said force transfer member at a predetermined distance from said vertical mount and a second end pivotally connected to said drive arm such that a first quadrilateral is established by the axes of the pivotal connections between the first tie rod and said force transfer member and said drive arm, the pivotal axis of the drive arm relative to the main frame, and the pivotal axis of the force transfer vertical mount;
• said operative means further including a second tie rod having a first end pivotally connected to a distal end of said force transfer member at a second predetermined distance from the force transfer vertical mount and a second end pivotally connected to said driven arm such that a second quadrilateral is established by the axes of the pivotal connection between the second tie rod with said force transfer member and the driven arm, the pivotal axis of the driven arm relative to the main frame, and the pivotal axis of the force transfer vertical mount;
• and wherein one of the quadrilateral formations has a non-parallelogram configuration to proportionately reduce the turning angle of the steering wheel relative to the steering angle of the implement.