Seatbelt retractor

1. A seat belt retractor for an occupant restraint device, comprising:

a rotating member, wherein the seat belt is configured to wind and unwind around the rotating member to thereby permit at least a portion of the seat belt to be stored in the retractor or withdrawn from the retractor;

a housing including a first pivot and a second pivot;

an actuator pivotally coupled to the housing at the first pivot;

an inertia sensing element pivotally coupled to the housing at the second pivot;

a plurality of separated ferromagnetic elements fixed to the housing; and

an electromagnetic element coupled to the sensing element at a distal end from the second pivot;

wherein, when subject to a force due to an acceleration, the sensing element is configured to pivot relative to the housing to in-turn rotate the actuator to selectively prohibit rotation of the rotating member in at least a seat belt withdrawing direction; and

wherein the electromagnetic element is configured to impart an electromagnetic force on each ferromagnetic element to retard the movement of the sensing element when the force due to the acceleration is below a threshold.

2. The retractor of claim 1 , wherein the sensing element is a pendulum configured to rotate relative to the housing, such that the electromagnetic element rotates about a pivot axis of the second pivot along a first radius.

3. The retractor of claim 2 , wherein the each ferromagnetic element is configured as a rod that is retained by the housing.

4. The retractor of claim 3 , wherein each rod is contained within a separate channel of the housing.

5. The retractor of claim 4 , wherein each adjacent pair of ferromagnetic elements are offset by an arc length that is common to the arc lengths of the other adjacent pairs of ferromagnetic elements.

6. A seat belt retractor for an occupant restraint device, comprising:

a rotating member, wherein the seat belt is configured to wind and unwind around the rotating member to thereby permit at least a portion of the seat belt to be stored in the retractor or withdrawn from the retractor;

a housing including a first pivot and a second pivot;

an actuator pivotally coupled to the housing at the first pivot;

an inertia sensing element pivotally coupled to the housing at the second pivot

at least one ferromagnetic element fixed to the housing, wherein each ferromagnetic element is configured as a rod that is retained in a channel in the housing; and

an electromagnetic element coupled to the sensing element at a distal end from the second pivot

wherein, when subject to a force due to an acceleration, the sensing element is configured to pivot relative to the housing to in-turn rotate the actuator to selectively prohibit rotation of the rotating member in at least a seat belt withdrawing direction;

wherein the electromagnetic element is configured to impart an electromagnetic force on the ferromagnetic element to retard the movement of the sensing element when the force due to the acceleration is below a threshold;

wherein the sensing element is a pendulum configured to rotate relative to the housing, such that the electromagnetic element rotates about a pivot axis of the second pivot along a first radius; and

wherein the at least one ferromagnetic element includes a plurality of separated ferromagnetic elements with each ferromagnetic element fixed to the housing.

7. The retractor of claim 6 , wherein each ferromagnetic element of the plurality of ferromagnetic elements is arranged on a second radius from the pivot axis of the second pivot, and wherein the second radius is greater than the first radius.

8. The retractor of claim 7 , wherein each adjacent pair of ferromagnetic elements are offset by an arc length that is common to the arc lengths of the other adjacent pairs of ferromagnetic elements.

9. A seat belt retractor for an occupant restraint device, comprising:

a rotating member, wherein the seat belt is configured to wind and unwind around the rotating member to thereby permit at least a portion of the seat belt to be stored in the retractor or withdrawn from the retractor;

a housing including a first pivot and a second pivot;

an actuator pivotally coupled to the housing at the first pivot;

an inertia sensing element pivotally coupled to the housing at the second pivot;

an electromagnetic element coupled to the sensing element at a first radius from the second pivot; and

a plurality of separated ferromagnetic elements provided at a second radius from the second pivot, wherein each adjacent pair of ferromagnetic elements is offset by an arc length;

wherein, when subject to a force due to an acceleration, the sensing element is configured to pivot relative to the housing to in-turn rotate the actuator to selectively prohibit rotation of the rotating member in at least a seat belt withdrawing direction; and

wherein the electromagnetic element is configured to impart an electromagnetic force on each ferromagnetic element to retard the movement of the sensing element when the force due to the acceleration is below a threshold.

10. The retractor of claim 9 , wherein each ferromagnetic element is configured as a rod that is retained in a channel in the housing.

11. The retractor of claim 9 , wherein the second radius is greater than the first radius.

12. The retractor of claim 9 , wherein the sensing element is a configured to rotate relative to the housing, such that the electromagnetic element rotates about a pivot axis of the second pivot along the first radius.