Patent ID: 7377337
Filing Date: 2008-05-27
Classification: E21B,F16D

Abstract:
1. A downhole drilling tool comprising a drillstring and a drilling head, wherein a freewheel for transferring drive from the drillstring to the drilling head is positioned between the drillstring and the drilling head, the freewheel comprising: a first race; a second race; and a locking element interposed between said first and second races; one of said races having a wedge-shaped depression upon which the locking element moves between a disengaged position in which the first race is disengaged from the second race and an engaged position in which the locking element locks the first and second races together, and the other of said races having a depression formed in a surface thereof, the depression being shaped to receive at least a portion of the locking element when the locking element is in the engaged position; wherein the wedge-shaped depression is formed in an end face of the first race, and the depression is formed in an end face of the second race.