REVERSIBLE IMPACT MECHANISM HAVING STRUCTURE TO LIMIT HAMMER TRAVEL

摘要

PROBLEM TO BE SOLVED: To provide an improved impact mechanism, such as an impact wrench comprising a motor; a shaft coupled to the motor and having a first shaft groove with first and second axial end parts; and a hammer arranged around the shaft and having a first hammer groove. SOLUTION: A hammer 44 is coupled to a shaft 24 such that a ball 36 is arranged in a first hammer groove 48 and a first shaft groove 28 and axial rotatable relative movement with the ball 36 movable along the groove is effected. Further, a wrench comprises a rotatable anvil 52 coupled to a load; a bias member 58 to engage the hammer 44 with the anvil 52 with the hammer axially elastically biased; and a stop structure 60 wherein the ball 36 is arranged along a shaft 24 in a manner not to make contact with the second axial end part of the first shaft groove 28 and engaged with the hammer 44 to limit axial movement of the hammer 44 separating away from the anvil 52.