This valve is used to control the flow direction manually. A spool is shifted by operating a hand lever (Figure 5-27). In a spring offset model, a spool is normally in an extreme out position and is shifted to an extreme in position by moving a lever toward a valve. Spring action automatically returns both spool and lever to the normal out position when a lever is released. In a two-position, no-spring model, a spool is shifted back to its original position. (Figure 5-27 does not show this valve.) In a three-position no-spring model, a detent (a devise which locks the movement) retains a spool in any one of the three selected positions after lever force is released. In a three-position, spring-centered model, a lever is used to shift a spool to either extreme position away from the center. Spring action automatically returns a spool to the center position when a lever is released.
