Trailer and steerable wheels therefor

A method of steering the wheels of a two wheel trailer, and comprising the steps of:

• detecting an articulation angle between said trailer and a towing vehicle;
• steering said wheels by changing a wheel steering angle automatically according to changes in said articulation angle;
• identifying forward and rearward directions of travel of said trailer;
• providing a fluid circuit having a motive fluid for effecting said steering in response to said detecting and for interconnecting said angle detecting and said steering via said circuit;
• providing a valve for controlling a direction of flow of said motive fluid;
• and
• controlling routing of said motive fluid through said circuit via said directional control valve and automatically according to each of said directions of travel so as to provide a particular sense of said wheel steering angle according to said direction of travel.

An apparatus for steering the wheels of a two wheel trailer, and comprising:

• means for monitoring an angle of articulation in magnitude and sense between said trailer and a towing vehicle and generating articulation angle signals in response thereto;
• means for monitoring an angle of wheel steering in magnitude and sense relative to an axle of said trailer and generating wheel steering angle signals in response thereto;
• means for receiving said articulation angle signals and computing values of said articulation angle as a percentage of a range of articulation to either side of 0.degree.;
• means for receiving said wheel steering angle signals and computing values of said wheel steering angle as a percentage of a range of steering to either side of 0.degree.;
• means for comparing said articulation percentage values with said wheel steering percentage values and generating a correction signal whenever said articulation and wheel steering percentage values are not of equal magnitude;
• and
• means, responsive to said correction signal, for turning said wheels to adjust said wheel steering angle, whenever said articulation percentage value and said wheel steering percentage value are not equal in magnitude, in order to make said percentage values equal.

An apparatus for steering the wheels of a two wheel trailer, and comprising:

• means for detecting an articulation angle between said trailer and a towing vehicle;
• means for steering said wheels by changing a wheel steering angle automatically according to changes in said articulation angle;
• means for identifying forward and rearward directions of travel of said trailer;
• a fluid circuit having a motive fluid for effecting said steering in response to said detecting and for interconnecting said angle detecting and said steering via said circuit;
• valve means for controlling a direction of flow of said motive fluid;
• and
• means for controlling routing of said motive fluid through said circuit via said valve means and automatically according to each of said directions of travel so as to provide a particular sense of said wheel steering angle according to said direction of travel.

An apparatus for steering the wheels of a two wheel trailer and comprising:

• means for attaching said trailer to a towing vehicle such that said trailer is pivotal above yaw, pitch, and roll axes;
• and
• means for converting movement of said trailer about said yaw axis into a motive force for said steering, said motive force being transmitted via a fluid;
• and
• means for controlling said steering in response to and according to forward and reverse directions for travel of said trailer in order to accomplish said steering in forward and reverse directions of travel.