When driving segment gear 1, meshing with the rack of valve spool 2, is turned, spool 2 is shifted to the right or left of the neutral position (as shown). This admits fluid under pressure into the system through passage a, the holes in guide sleeve 3 and passages and grooves to annular groove d of the spool. Depending upon the position of valve spool 2, fluid is delivered to one of the ends of cylinder 4. This moves piston 5, and the rack teeth on the piston rod turn driven gear 6 in the corresponding direction. Fluid from the exhaust end of cylinder 4 is discharged through the axial hole in spool 2 and port b.
$4034$THP,Dr$