Rotatable spindle pilot valve

Claim 1

A VALVE OF THE TYPE HAVING A VALVE BODY WITH A BORE THEREIN AND A SPINDLE ROTATABLE IN THE BORE AND BY WHICH COMMUNICATION IS CONTROLLED BETWEEN PORTS IN THE VALVE BODY THAT OPEN FROM ITS BORE, SAID VALVE BEING CHARACTERIZED BY THE FOLLOWING: (A) THE BODY HAS A PAIR OF MAIN PORTS, ONE OPENING FROM ITS BORE NEAR EACH END THEREOF, AND A PLURALITY OF CONTROLLED PORTS OPENING FROM THE BORE IN A ZONE INTERMEDIATE THE MAIN PORTS; (B) THE SPINDLE IS ENCIRCLED BY THREE AXIALLY SPACED APART LANDS WHICH SEALINGLY ENGAGE THE SURFACE OF THE BODY BORE AROUND ITS ENTIRE CIRCUMFERENCE, (1) SAID LANDS BEING DISPOSED IN PLANES WHICH ARE PARALLEL TO ONE ANOTHER AND OBLIQUELY INCLINED TO THE SPINDLE AXIS, AND (2) ALL PORTIONS OF THE LANDS BEING LOCATED BETWEEN A PAIR OF PLANES NORMAL TO THE SPINDLE AXIS WHICH ARE SPACED AXIALLY INWARD FROM THE MAIN PORTS AND DEFINE SAID ZONE, SO THAT THE LANDS AT ALL TIMES PREVENT COMMUNICATION THROUGH THE BORE BETWEEN THE MAIN PORTS; AND (C) THE SPINDLE HAS A PAIR OF PASSAGES THERETHROUGH, EACH OF WHICH COMMUNICATES ONE OF THE SPACES BETWEEN LANDS WITH AN END PORTION OF THE BORE WHICH IS AXIALLY REMOTE FROM THE LANDS DEFINING THAT SPACE, SO THAT WHEN THE SPINDLE IS IN A POSITION OF ROTATION SUCH THAT A SPACE BETWEEN LANDS REGISTERS WITH ONE OF SAID CONTROLLED PORTS, THE LATTER PORT IS COMMUNICATED WITH A MAIN PORT THROUGH THE PASSAGE OPENING TO THAT SPACE.