Vehicle steering brake and clutch control

In a vehicle in which driving force is applied to both sides thereof, including clutch systems associated respectively with both sides thereof, and responsive to fluid pressure from a source thereof, each clutch system associated with a side of the vehicle comprising clutch means disengageable to disconnect the driving force applied to that side of the vehicle and engageable to connect the driving force to that side of the vehicle, a control apparatus for each clutch system comprising:

• a valve comprising a valve body defining a bore, and a valving spool movably disposed within and along said bore;
• first means for providing fluid communication between said source and said valve body bore;
• second means for providing fluid communication between said valve body bore and said clutch means;
• additional means for providing fluid communication from said valve body bore and through which fluid pressure may be released from said valve body bore;
• the valve spool being movable within said bore to first and second positions relative to said valve body, the valving spool in said first position allowing release of fluid pressure from said clutch means through said second means for providing fluid communication and said additional means for providing fluid communiation, the valving spool in the second position providing communication of fluid pressure from said source through said first means for providing fluid communication, through said second means for providing fluid communication, to the clutch means;
• the clutch means being applied upon release of fluid pressure therefrom, and released upon application of fluid pressure thereto;
• and
• actuator means operatively coupled with said valving spool for providing that movement of said actuator means in one direction provides movement of the valving spool to its first position, and movement of the actuator means in another direction provides movement of said valving spool to its second position;
• means for resiliently biasing said actuator means for movement in said one direction;
• and
• means operatively associated with said actuator means for providing that, upon said movement of said actuator means in said one direction under the resilience of said resilient biasing means to provide movement of said valving spool toward its first position from its second position, said valving spool is moved from its second toward its first position initially at a certain rate, and subsequently at a slower rate, said slower rate of movement substantially corresponding to release of fluid pressure from said clutch means through said second means for providing fluid communication and said additional means for providing fluid communication, providing for engagement of said clutch means.