HYDRAULIC DIRECTIONAL CONTROL VALVES

摘要

This invention relates to a manually operable spool-type fluid pressure control valve that has a releasable locking mechanism to maintain the spool valve in certain of its positions until subjected to an axial force in excess of a chosen value. This locking mechanism comprises a plurality of balls and a pair of cam surfaces along which the balls roll when the spool valve is manually moved from one position to another. A fluid pressure force effective on one of the cam surfaces biases it against the balls to maintain them in either of two positions until the spool valve is subject to an external force in excess of the chosen value.