Patent ID: 7334647

Claim:
An overload clutch assembly for a power tool having a spindle for rotatingly driving a working member of the tool and a motor for rotatingly driving the spindle via the overload clutch assembly; the overload clutch assembly having a first mode in which rotary drive is transmitted to the spindle when a torque below a first predetermined level is applied to the clutch, and transmission of rotary drive to the spindle is cut when a torque above the first predetermined level is applied to the clutch, and a second mode in which rotary drive is transmitted to the spindle when a torque below a second predetermined level, which is higher than the first predetermined torque, is applied to the clutch assembly, and transmission of rotary drive to the spindle is cut when a torque above the second predetermined level is applied to the clutch; the overload clutch assembly capable of being between switched between the first mode and the second mode by an actuator; wherein the clutch assembly comprises a carrier rotationally mounted on an output clutch spindle, one of the carrier and the output clutch spindle being drivingly connected to the motor, the other of the carrier and the output clutch spindle being drivingly connected to the spindle; a first clutch plate non rotationally mounted on the output clutch spindle, the carrier and the first clutch plate arranged so that the first clutch plate engages with the carrier for the transfer of rotational drive between the carrier and the first clutch plate when the torque is below the first predetermined level, but rotational drive is cut between the carrier and the first clutch plate when the torque is above the first predetermined level; a second clutch plate mounted on the output clutch spindle, the second clutch plate non rotationally connectable to the output clutch spindle by the actuator when the clutch is in the second mode, the carrier and the second clutch plate arranged so that, when the second clutch plate is non rotationally connected to the clutch spindle, the second clutch plate engages with the carrier to transfer rotational drive between the carrier and the second clutch plate when the torque is below the second predetermined level, but rotational drive is cut between the carrier and the second clutch plate when the torque is above the second predetermined level; and when the overload clutch assembly is in the second mode, the torque is transferred from the carrier to the output clutch spindle via the second clutch plate only.