Patent ID: 7891441

Claim:
An expandable downhole tool for incorporation in a drillstring, the tool capable of being adjusted between activated and deactivated modes, said tool comprising: a tool body; a working component mounted indirectly on the tool body for movement relative to the tool body between a withdrawn inoperative position and an outwardly deployed operative position corresponding respectively to the deactivated and activated modes of the tool; a mandrel slidably mounted in the tool body for axial movement between first and second positions, said mandrel taking up the first axial position in the deactivated mode of the tool and being displaceable to the second axial position in order to activate the tool to its activated mode; a sloping guide ramp defining an outwardly extending guide path disposed in a recess in the tool body, wherein a first end of the working component is held captive by the sloping guide ramp as it moves between the inoperative and operative positions; and at least one first travel block coupled with the mandrel for movement therewith, in which said at least one said first travel block has a pivotal connection with an adjacent second end of the working component, wherein as the mandrel moves from its first position to its second position the working component moves along the outwardly extending guide path from its withdrawn inoperative position to its outwardly deployed operative position.