Electronically controlled seat belt module

In combination

• a seat belt assembly for a seated occupant in a vehicle including a seat belt and a buckle on said seat belt for anchoring in a vehicle with said seat belt about the occupant;
• an electronically controlled seat belt module including a shaft, a spool rotatably mounted on said shaft for winding of an end of said seat belt thereon, a first plurality of poles mounted on said shaft, a second plurality of poles mounted on said spool in alternating relation with said first plurality of poles, a magneto-rheological fluid disposed between adjacent poles of said first and said second plurality of poles, and at least one electromagnetic coil mounted between said shaft and said spool to create a magnetic field passing through said poles of said first and said second plurality of poles to change the viscosity of said fluid upon actuation of said coil;
• and
• a central processing unit operatively connected to said coil for delivering a programmed current over time to said coil to initially lock said spool against rotation relative to said shaft and to subsequently release said spool at a specific rate and profile to allow said belt to unwind from said spool at a rate to minimize the belt load on the occupant during a crash.

An electronically controlled seat belt module comprising

• a shaft;
• a spool disposed concentrically of said shaft;
• a motor for rotating said spool about said shaft for winding of a seatbelt thereon;
• a first plurality of poles mounted on said shaft;
• a second plurality of poles mounted on said spool in alternating relation with said first plurality of poles;
• a magneto-rheological fluid disposed between adjacent poles of said first and said second plurality of poles;
• and
• at least one electromagnetic coil mounted between said shaft and said spool to create a magnetic field passing through said poles of said first and said second plurality of poles to rigidify said fluid upon actuation of said coil.