Patent ID: 8651198

Claim:
A spindle lock device in a screwdriver, the screwdriver comprising: a body case; an electric motor disposed within the body case; a drive shaft rotatably driven by the electric motor; a hammer having a rotational axis and axially movably and rotatably supported on the drive shaft; an anvil having a spindle portion that is rotatable about the rotational axis of the hammer, the spindle portion being configured to mount a driver bit to the spindle portion; and an impact device configured such that the hammer impacts on the anvil in a rotational direction while the hammer reciprocates in an axial direction; the spindle lock device comprising: an engaging ring fixed in position relative to the body case, wherein the anvil is disposed inside of the engaging ring; a flat relief surface defined on an outer circumference of the anvil; and an engaging member disposed between the engaging ring and the flat relief surface of the anvil; wherein the engaging member is configured to wedge between the engaging ring and an end portion of the flat relief surface in a circumferential direction of the relief surface of the anvil, whereby the anvil is locked with respect to rotation relative to the body case; wherein when the anvil is locked, the spindle portion is prevented from rotating relative to the engaging ring and the body case; wherein the engaging member includes a cylindrical pin, wherein the cylindrical pin rotates along the flat relief surface to wedge between the engaging ring and the end portion of the relief surface as the engaging ring is rotated relative to the anvil, whereby the engaging member directly contacts the engaging ring; wherein the anvil includes an impact receiving portion and the spindle portion separated from each other; wherein the impact receiving portion includes first engaging portions; wherein the spindle portion includes a second engaging portion engageable with the first engaging portions in the rotational direction, and the spindle portion is configured to rotate relative to the impact receiving portion about the rotational axis within a predetermined range; wherein the flat relief surface is positioned on a circumferential surface of the spindle portion; wherein the engaging member is positioned between the first engaging portions of the impact receiving portion in the circumferential direction; and wherein the engaging member is non-elastic.