Extendable cutting tools for use in a wellbore

A tool for use in a well bore, comprising

• a first tubular body having a bore therethrough, an opening through a wall thereof, a connector at each longitudinal end thereof, and a first actuation profile formed in a surface thereof adjacent the opening;
• a first arm:
• pivotally connected to a first piston, and rotationally coupled to the first tubular body,
• disposed in the opening in a retracted position,
• movable to an extended position where an outer surface of the first arm extends outward past an outer surface of the first tubular body, and
• having a second actuation profile formed in an inner surface thereof and corresponding to the first actuation profile;
• the first piston:
• disposed in the body bore,
• having a bore therethrough, and
• operable to move the first arm from the retracted position to the extended position in response to fluid pressure in the piston bore exceeding fluid pressure in the opening;
• a lock operable to retain the first piston in the retracted position;
• and
• a second piston operably coupled to the lock,
• wherein:
• the first piston extends the first arm by moving longitudinally relative to the first tubular body, thereby moving the first arm along the first actuation profile,
• the first arm rotates about the pivotal connection and relative to the first tubular body during extension,
• each actuation profile has a shoulder and the shoulders are engaged in the extended position,
• the shoulders are disengaged in the retracted position,
• each actuation profile further has a longitudinally inclined portion and a longitudinally flat portion, and
• each shoulder is formed between the respective longitudinally inclined portion and longitudinally flat portion.

A tool for use in a well bore, comprising

• a first tubular body having a bore therethrough, an opening through a wall thereof, a connector at each longitudinal end thereof, and a first actuation profile formed in a surface thereof adjacent the opening;
• a first arm:
• pivotally connected to a first piston, and rotationally coupled to the first tubular body,
• disposed in the opening in a retracted position,
• movable to an extended position where an outer surface of the first arm extends outward past an outer surface of the first tubular body, and
• having a second actuation profile formed in an inner surface thereof and corresponding to the first actuation profile;
• the first piston:
• disposed in the body bore,
• having a bore therethrough, and
• operable to move the first arm from the retracted position to the extended position in response to fluid pressure in the piston bore exceeding fluid pressure in the opening;
• a lock operable to retain the first piston in the retracted position;
• a second piston operably coupled to the lock;
• a fastener pivotally connecting the first arm and the first piston;
• and
• a torsion spring disposed around the fastener and biasing the first arm radially inward,
• wherein:
• the first piston extends the first arm by moving longitudinally relative to the first tubular body, thereby moving the first arm along the first actuation profile, and
• the first arm rotates about the pivotal connection and relative to the first tubular body during extension.

A tool for use in a well bore, comprising

• a first tubular body having a bore therethrough, an opening through a wall thereof, a connector at each longitudinal end thereof, and a first actuation profile formed in a surface thereof adjacent the opening;
• a first arm:
• pivotally connected to a first piston, and rotationally coupled to the first tubular body,
• disposed in the opening in a retracted position,
• movable to an extended position where an outer surface of the first arm extends outward past an outer surface of the first tubular body, and
• having a second actuation profile formed in an inner surface thereof and corresponding to the first actuation profile;
• the first piston:
• disposed in the body bore,
• having a bore therethrough, and
• operable to move the first arm from the retracted position to the extended position in response to fluid pressure in the piston bore exceeding fluid pressure in the opening;
• a lock operable to retain the first piston in the retracted position;
• and
• a second piston operably coupled to the lock,
• wherein:
• the first piston extends the first arm by moving longitudinally relative to the first tubular body, thereby moving the first arm along the first actuation profile,
• the first arm rotates about the pivotal connection and relative to the first tubular body during extension from the retracted position to the extended position, and
• each actuation profile has a longitudinally inclined portion, a longitudinally flat portion, and a shoulder formed between the inclined and flat portions.