Impact wrench mechanism and pivot clutch

A rotary impact tool comprising, in combination, a housing, a motor having a rotor mounted in said housing, an output shaft mounted on said housing for rotation and including impact receiving anvil jaw means generally radially disposed on its periphery, carrier member means coaxially around said output shaft and mounted for rotation in respect to said output shaft, driving connecting means between said rotor and said carrier member means for rotating said carrier member means, hammer member means pivotally connected in said carrier member means for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the axis of rotation of said carrier member means, said hammer member means for clockwise impact operation having clockwise impact delivering jaw means on its inside surface means located between 0.degree. and 90.degree. clockwise from its pivot connection to the carrier member means, said impact jaw means being movable into and out of the path of said impact receiving anvil jaw means to deliver impact blow(s) thereto, cam means for effecting the angular pivot movement of said impact delivering jaw means into the path of said anvil jaw means in a clockwise direction relative to said carrier member means, centrifugal force created by the proportions, mass and mass center location of said hammer member means holding said impact delivering jaw means in the path of said anvil jaw means until the delivery of said impact blows thereto, said impact delivering jaw means being so shaped and positioned that when in forceful contact with said anvil jaw means a counterclockwise pivot torque is created acting on said hammer means tending to pivot it out of engagement with said anvil jaw means, inertia forces created by the proportions, mass and mass center location of said hammer means preventing said counterclockwise pivot motion of said hammer means until the conclusion of the impact blow;

• said carrier member means comprising a front plate and a rear drive member, each having at least one hole therein, offset axially from said output shaft, and longitudinal pin means extending into said at least one hole in said front plate and rear drive member connecting said plate and member together for said carrier member means rotation and providing pivot means for said hammer member means.