Rotary Impact Tool

摘要

A rotary impact tool assembled in a drill string transfers torque and axial force between two components. The rotary impact tool includes an anvil and a hammer axially aligned with engaging faces. At a threshold torque, the hammer disengages from the anvil and rotates freely until a biasing element displaces the hammer to reengage the anvil. Kinetic energy stored in the hammer is transferred to the anvil when the faces of the hammer and anvil reengage. This provides an impact to the anvil and any attached component. The tool can accommodate misalignment of the attached components.

主权项

1. Apparatus for using in a downhole drill string transmitting torque between drill string components providing protection from excessive torque generated in the drill string, comprising:
a first portion and second portion for transmitting torque from one to the other when in an engaged position, and not transmitting torque when in a disengaged position; the first portion having at least one hammer face and the second portion having at least one anvil face, the first and second portions being movable axially relative to each other between the engaged position in which the at least one hammer face is aligned with the at least one anvil face for engagement to transmit torque between the first and second portions, and the disengaged position in which the at least one hammer face is not aligned for engagement with the at least one anvil; and a biasing component for urging the first portion toward engagement with the second portion; wherein, when the torque applied across the apparatus exceeds a threshold value, the first portion and the second portions move far enough axially away from each other to reach the disengaged position, thereby permitting the hammer and anvil faces to move momentarily out of alignment and allow the first and second portions to rotate in opposite directions with respect to each other in response to torque applied to the them; and wherein the biasing component urges the first and second portions into the engaged position and the at least one hammer face and at least one anvil face into alignment for engagement for transmitting an impulse of torque.