Patent ID: 7334642

Claim:
A radially expandable tool comprising: a tool body; a radially moveable member coupled to the tool body and in force receiving relation to a constant force actuator, wherein the radially moveable member is movable by the constant force actuator from an closed position to a plurality of radially expanded open positions, which includes a fully open position; the constant force actuator comprising: an opening arm having a force transmission member; and a movement control guide in force reacting engagement with the force transmission member; and a linear force generator; which applies a linear force to the constant force actuator, which the actuator transfers to a radial force perpendicular to the linear force, and wherein when the linear force is constant, the radial force transferred by the actuator is constant for each radial position of the radially moveable member from the closed position to the fully opened position due to the interaction of the force transmission member and the movement control guide.