Patent ID: 7748462
Filing Date: 2010-07-06
Classification: E21B

Abstract:
1. An actuating mechanism for operating a tool used in a well bore, the mechanism comprising first and second pistons; the first piston including a damping element for delaying movement of the first piston relative to the second piston under an applied pressure; the second piston acting on a retaining element; the retaining element adapted to hold the second piston in an intermediate position when the applied pressure is within a predetermined range and allow movement of the first piston to a final position; the retaining element allowing the second piston to move to a secondary position when the applied pressure is above the predetermined range; a locking element which prevents movement of the first piston when the second piston is in the secondary position; an actuating member whose movement operates the tool; and a securing element for retaining the actuating member in a first position until released by virtue of the first piston reaching the final position, whereby the actuating member moves to a second position and operates the tool.