公开(公告)号：JPH0252651A

公开(公告)日：1990-02-22

申请号：JP16648389

申请日：1989-06-28

Applicant: APPLIED POWER INC

Inventor： FUREETO UEE SHIYUMAARE ,  TOONE OODERAA

IPC: F15B11/00 ,  A61G7/00 ,  A61G7/012 ,  A61G7/018 ,  F15B1/02 ,  F15B1/027

Abstract: PURPOSE: To prevent undesired rising of an object due to the decrease of load by exposing the largest and smallest end surfaces of a spool member to the pressure of a branch conduit and exposing the differential surface to the pressure of a return conduit. CONSTITUTION: A multi-pilot-operated check valve 21 is attached at a branch conduit 14. The largest operation surface of a differential spool 22 is exposed to the pressure inside the branch conduit 14 by way of a pilot control conduit 14', and the smallest surface is also exposed to the pressure inside the branch conduit 14. The spool 22 is moved to the left by the pressure supplied to the ring-shaped spool surface between the largest surface and the smallest surface of the spool 22 by way of the pilot control conduit 24 together with the pressure imposed on the smallest spool surface, and a check valve 23 is closed. Even if the piston load is reduced, the supported part will not make undesirable movement since the check valve 23 is closed and liquid is not supplied from an accumulator 15.