Patent attributes
A tool includes a housing between an outer wall and an inner wall that surrounds a longitudinal tool bore. First and second axially spaced ports connect the housing to the tool bore. An unlocking piston seals across the first port and an arming sleeve seals across the second port. A Locking ring is held in place by a retaining ring and prevents the arming sleeve from sliding towards the unlocking piston to open the second port. An unlocking tool bore pressure at the first port moves the unlocking piston axially to displace the retaining ring and unlock the tool. A lower, arming tool bore pressure moves the arming sleeve in the unlocked tool to open the second port and arms the tool. An actuating tool bore pressure, which is less that the unlocking pressure, actuates a valve piston via the open second port.
