| 摘要 |
A double-acting spool-type hydraulic control valve having a spring centered spool is described, the spool centering spring being arranged in conventional manner between two spring seats which bear in opposite directions on an end portion of the spool within a cover secured to one end face of the valve body. The spool is capable of a degree of over-travel beyond each of the maximum flow positions, which over-travel is resisted by an auxiliary spring arranged within the centering spring. Ball-and-recess type detent elements are provided for holding the spool at either of the maximum flow positions, these detent elements being arranged at the free end of the centering spring cover. The recessed detent element is shiftable on the spool axis between stops so that the spool can shift to a detented maximum flow position after having been forced to over-travel to permit registration between ball and recess.
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