Seat belt retractor with electrically actuatable locking mechanism
AssigneeTRW Vehicle Safety Systems Inc.
InventorRobert J. Rumpf
Life of this patent
Estimating the term…
Abstract
A seat belt retractor comprises a spool which is rotatable in seat belt winding and unwinding directions. An inertia member is rotatable with the spool at spool accelerations below a predetermined level and rotatable relative to the spool at spool accelerations above the predetermined level. The spool is blocked against from rotation in the unwinding direction in response to relative rotation of the inertia member and the spool. The inertia member is restrained from rotation to effect rotation relative to the spool by an electromagnet having opposite poles extending adjacent the inertia member. The electromagnet is energized to create a magnetic field extending through the poles to cause the poles to be attracted against the inertia member to restrain rotation of the inertia member.
Claims21
A seat belt retractor comprising:
- a spool rotatable in seat belt winding and unwinding directions;
- a member rotatable with said spool at spool accelerations below a predetermined level and rotatable relative to said spool at spool accelerations above the predetermined level;
- locking means for locking said spool against rotation in the unwinding direction in response to relative rotation of said member and said spool;
- and
- means for restraining rotation of said member to effect relative rotation of said member and said spool comprising
- an electromagnet having opposite poles extending adjacent said member, and
- means for energizing said electromagnet to create a magnetic field extending through said poles and said inertia member to cause said poles to be attracted against said member to restrain the rotation of said member.
An apparatus comprising:
- a member rotatable about an axis;
- means actuated in response to slowing of the rotation of said member;
- an electromagnet having opposite poles fixed against rotation and extending adjacent to the periphery of said member;
- means for supporting said poles for movement relative to said member;
- and
- means for energizing said electromagnet to create a magnetic field extending through said poles and said member to cause said poles to be attracted against said member to slow the rotation of said member.
A seat belt retractor comprising:
- a spool rotatable in seat belt winding and unwinding drections;
- a disk member rotatable with said spool at spool accelerations below a predetermined level and rotatable relative to said spool at spool accelerations above the predetermined level, said disk member being made of a material having a high magnetic permeability.
- locking means for locking said spool against rotation in the unwinding direction in response to relative rotation of said disk member and said spool;
- and
- means for restraining rotation of said disk member to effect relative rotation of said disk member and said spool comprising
- an electric coil which is energized in response to a predetermined condition for creating a magnetic field through said disk member, and
- at least one member disposed adjacent said disk member and movable in response to energization of said coil by the magnetic force created between the disc member at the least one member into frictional engagement with said disk member to restrain the rotation of said disk member to effect relative rotation of said disk member and said spool.
A seat belt retractor as set forth in claim 14 wherein said locking means includes a ratchet wheel connected to and rotatable with said spool and a pawl movably supported for engaging said ratchet wheel to lock said spool from rotation in the belt unwinding direction.
Dependencies are inferred from the claim text.