Patent ID: 9476273
Filing Date: 2016-10-25
CPC Classification: E21B

Claim Text:
1. A system for activating a down hole tool in a wellbore, the system comprising: a base pipe having an interior and defining a port that extends between the interior and an activation chamber defined on an exterior of the base pipe; a piston having a first end exposed to the activation chamber and a second end coupled to the down hole tool such that movement of the piston within the activation chamber acts on and activates the down hole tool; a sleeve positioned in the interior of the base pipe and including a constant inner diameter and a stepped outer diameter such that a first axial end of the sleeve has a first area and a second axial end of the sleeve has a second area smaller than the first area; an annular collar provided within the interior of the base pipe to receive the second axial end of the sleeve, the sleeve being moveable between an unactivated position, where the sleeve blocks the port, and an activated position, where the port is exposed and fluid communication between the interior and the activation chamber is allowed; and a latch member that prevents movement of the sleeve from the unactivated position to the activated position until a predetermined force is assumed by the sleeve, wherein increasing a pressure in the interior generates a force differential between the first and second axial ends, and when the force differential is substantially equal to the predetermined force, the latch member releases and the sleeve moves to the activated position, thereby pressurizing the activation chamber to force the piston to activate the down hole tool.