Patent ID: 6230826
Filing Date: 2001-05-15
Classification: E21B

Abstract:
An excavation bit comprising a main body having a rotational axis which is coaxial with a longitudinal axis of a drill rod when connected to said bit;at least one carrier rotatably connected to said main body and having excavation means positioned about its periphery;each carrier having an axis of rotation at an angle to said main body rotational axis when said carrier is viewed from its front or rear, said axis of rotation including a lateral offset from said main body rotational axis so that said axis of rotation of each carrier does not intersect with said main body rotational axis;said angle being such as to locate said excavation means at or near to said longitudinal axis at a location away from said body in a direction of excavation when in use;said carrier having a rotation direction opposite to the rotation direction of the main body when said rotation directions are viewed along the direction of said longitudinal axis when said bit is in use; andwherein said at least one carrier receives motive power from said drill rod; andwherein rotation of said at least one carrier results in the rotation of said main body around said main body rotational axis.