Steering system for articulated vehicles

In a steering system for an articulated vehicle having a forward portion and a rearward portion pivotally connected to each other, wherein the steering system includes fluid actuated steering cylinder means adapted to cause angular motion of the forward portion of the vehicle relative to its rearward portion as dictated by a steering member, the combination thereof with:

• a source of fluid under pressure;
• a steering control valve adapted to control communication between said source and said steering cylinder means, said steering control valve being normally held closed in a center position and displaced on actuation to either of two offset positions;
• linkage means operatively connecting said steering member to said steering control valve whereby said steering control valve is actuated by said steering member;
• a fluid actuated follow-up cylinder having a piston operatively connected to said linkage means via a piston rod, said follow-up cylinder having a pair of opposed fluid chambers;
• locking means for normally locking said piston of said follow-up cylinder against movement in either direction;
• and
• follow-up cylinder actuating means operatively connected between said steering control valve and said steering cylinder means to selectively supply fluid under pressure to said fluid chambers of said follow-up cylinder upon actuation of said steering cylinder means, said locking means being adapted to unlock said piston of said follow-up cylinder when the fluid pressure in either of its fluid chambers builds up to a predetermined degree;
• whereby said follow-up cylinder when actuated by said actuating means functions to cause said linkage means to return said steering control valve to its center position.