Vehicle safety apparatus with selective energy management

A vehicle occupant safety apparatus comprising:

• a length of seat belt webbing extensible about a vehicle occupant to help protect the vehicle occupant;
• a retractor on which said belt webbing is wound;
• a base fixed in position relative to said retractor;;
• a first roller supported on said base for rotation relative to said base about a first axis, said first axis being fixed relative to said base;
• a second roller supported on said base for rotation relative to said base about a second axis spaced apart from said first axis, said second roller and said second axis being movable along said base in a direction toward said first roller;
• said belt webbing extending around said first and second rollers in an S-shaped pattern;
• electrically controlled blocking means engageable with said second roller, said blocking means having a first condition blocking movement of said second roller toward said first roller;
• and
• sensor means for detecting a condition indicative of a vehicle collision and for providing an electric release signal to said blocking means in response to sensing the condition;
• said blocking means being releasable in response to said electric release signal to enable movement of said second roller along said base toward said first roller to pay out webbing from said first and second rollers.