US Patent 8721236 Power tool arbor device

A power tool arbor assembly includes an arbor; an actuating member located at a second end of the arbor; and a friction member located at the second end of the arbor, the friction member being axially movable along the second end of the arbor. The friction member has a first axial position when no power tool accessory is attached to the second end of the arbor, the friction member being moveable toward a first end of the arbor from the first axial position to a second axial position in response to contact between the power tool accessory and the friction member, and the friction member being moveable toward the first end of the arbor from the second axial position to a third axial position when the actuating member is actuated.