Downhole cleaning tool and method

A downhole cleaning tool for location in a bore, the tool comprising:

• a tubular body defining an internal bore and at least one radially extending blade defining an external pocket having sides and a base;
• a cam member mounted in the body;
• a cam follower;
• and
• a radially extendable cleaning element mounted in the pocket and being operatively associated with the cam follower,
• wherein translation of the cam member relative to the cam follower moves the cleaning element from a retracted position towards an extended position,
• wherein the cleaning element comprises first and second radially extendable cleaning elements, wherein a first increment of translation of the cam member moves the first cleaning element from the retracted position towards the extended position without moving the second cleaning element, and a second increment of translation of the cam member moves the second cleaning element from the retracted position towards the extended position.

A downhole cleaning tool for location in a bore, the tool comprising:

• a tubular body defining an internal bore and at least one radially extending blade defining an external pocket having sides and a base;
• a cam member mounted in the body;
• a cam follower;
• and
• a radially extendable cleaning element mounted in the pocket and being operatively associated with the cam follower,
• wherein translation of the cam member relative to the cam follower moves the cleaning element from a retracted position towards an extended position and wherein the cam member is provided internally of the body and the cam follower extends through a port in the base of the pocket into contact with the cam member.

A downhole cleaning tool for location in a bore, the tool comprising:

• a tubular body defining an internal bore and at least one radially extending blade defining an external pocket having sides and a base;
• a cam member mounted in the body;
• a cam follower;
• and
• a radially extendable cleaning element mounted in the pocket and being operatively associated with the cam follower,
• wherein translation of the cam member relative to the cam follower moves the cleaning element from a retracted position towards an extended position wherein radial extension of the cleaning element is restricted by a stop member and further comprising a biasing arrangement configured to urge the cleaning element towards a maximum radial extension as permitted by the stop member.

A downhole cleaning tool for location in a bore, the tool comprising:

• a tubular body defining an internal bore and at least one radially extending blade defining an external pocket having sides and a base;
• a cam member mounted in the body;
• a cam follower;
• and
• a radially extendable cleaning element mounted in the pocket and being operatively associated with the cam follower,
• wherein translation of the cam member relative to the cam follower moves the cleaning element from a retracted position towards an extended position further comprising a shear member configured to retain the cleaning element in the retracted position, the shear member extending between the cleaning element and an axially movable member and being configured to shear on axial movement of the axially movable member relative to the body.

A downhole cleaning tool for location in a bore, the tool comprising:

• a tubular body defining an internal bore and at least one radially extending blade defining an external pocket having sides and a base;
• a cam member mounted in the body;
• a cam follower;
• and
• a radially extendable cleaning element mounted in the pocket and being operatively associated with the cam follower,
• wherein translation of the cam member relative to the cam follower moves the cleaning element from a retracted position towards an extended position wherein the pocket lies on an ellipse and the pocket, and the associated cleaning element have parallel ends and sides.

A drill string comprising at least two cleaning tools, each downhole cleaning tool comprising:

• a tubular body defining an internal bore and at least one radially extending blade defining an external pocket having sides and a base;
• a cam member mounted in the body;
• a cam follower;
• and
• a radially extendable cleaning element mounted in the pocket and being operatively associated with the cam follower,
• wherein translation of the cam member relative to the cam follower moves the cleaning element from a retracted position towards an extended position;
• and
• wherein the cleaning tools are incorporated in the drill string at axially spaced locations and define different cleaning diameters.