Clutch for selectively driving an accessory

A clutched apparatus comprising:

• a driver having a cylindrical torque transfer surface, the driver being adapted to be coupled to a source of rotary power to cause the driver to be rotated in a predetermined rotational direction;
• an output member capable of independent rotation relative to the driver, the output member having a first control member;
• a clutch spring formed of wire and having coils wound in a sense that is opposite to the predetermined rotational direction of the driver, the clutch spring having a first end and a second end that is opposite the first end, the coils being engaged to the cylindrical torque transfer surface;
• a spring control device comprising a second control member, which is coupled to the second end, and an armature;
• and
• an actuator that is operable in a disengaging mode and an engaging mode, wherein a force is generated when the actuator is operated in the disengaging mode, the force being transmitted to the armature such that the armature rotates relative to the driver in a rotational direction opposite the predetermined rotational direction to apply a control signal to the second end;
• wherein rotation of the driver in the predetermined direction when the actuator is operated in the engaging mode causes the coils of the clutch spring to drivingly engage the cylindrical torque transfer surface such that rotary power is transmitted in the predetermined rotational direction between the first end and the first control member;
• wherein the coils of the clutch spring at least partly release the cylindrical torque transfer surface when the driver is rotated in the predetermined rotational direction and the actuator is operated in the disengaging mode to limit transmission of rotary power in the predetermined rotational direction between the first end and the first control member;
• and
• wherein the actuator comprises a shoe that is driven into contact with the armature when the actuator is operated in the disengaging mode.

A clutched apparatus comprising:

• a driving member;
• an output member;
• a driver coupled to the driving member for rotation therewith;
• a clutch spring having a first end, a second end and a plurality of coils between the first and second ends, the first end being hook-shaped and engaged to the output member, the first and second ends being coupled to opposite ends of the coils, all of the coils being engage-able to a torque transfer surface to rotationally couple the output member to the driver, the torque transfer surface being an outer circumferential surface onto which the coils of the clutch spring are wound onto;
• and
• an actuator that is operable for causing the clutched apparatus to operate in a disengaged condition, the actuator comprising a coil, a return spring and an armature, the armature being coupled to the second end of the clutch spring for rotation therewith, the return spring biasing the armature in a first direction, the coil being configured to translate the armature against the bias of the return spring so that a frictional torque that resists rotation of the armature to cause the coils of the clutch spring to at least partially disengage the torque transfer surface.