Patent ID: 7591319

Claim:
An actuator device for a downhole tool, the actuator device capable of selectively actuating the downhole tool, the actuator device comprising: a housing having a chamber; an actuating member operatively connected to the housing, the actuating member having a piston carried within the chamber, wherein movement of the actuating member relative to the housing causes the downhole tool to perform a specified function; a gas releasing material disposed in the chamber on one side of the piston; and a port leading to the chamber for selectively delivering an activator fluid to the chamber, wherein the port extends to an exterior portion of the housing and the activator fluid is located in a wellbore, and wherein upon contact with the activator fluid, gas is released from the gas releasing material, which causes gas pressure to build up within the chamber sufficient to move the piston to cause the actuating member to actuate the downhole tool.