Patent ID: 6158526
Filing Date: 2000-12-12
Classification: B25B

Abstract:
An impact mechanism comprising:a motor;a shaft rotatable about an axis and coupled to the motor and having a first shaft groove with first and second axial ends;a hammer disposed about the shaft and having a first hammer groove;a ball disposed in the first hammer groove and in the first shaft groove and coupling the hammer to the shaft for relative axial and rotatable movement with the ball moveable along the grooves;a rotatable anvil for coupling to a load;a bias member resiliently biasing the hammer axially into engagement with the anvil; andstop structure formed of a plastic material and coupled to the shaft for engagement with the hammer to limit axial movement of the hammer away from the anvil so as to prevent the ball from contacting the second axial end of the first shaft groove, wherein the bias member is a coil spring and the spacer is totally disposed within the coils of the spring, and wherein the spacer has a front surface with a plurality of circumferentially spaced recesses formed therein.