Seat belt retractor

• US 20040262441A1
• Filed: 04/16/2004
• Published: 12/30/2004
• Est. Priority Date: 06/27/2003
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Japan K.K.
• Original Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Hiramatsu, Koji
• Granted Patent: US 7,354,014 B2
• Time in Patent Office: Days
• US Class Current: 242/379.1
• CPC Class Codes: B60R 2022/287 of torsion rods or tubes
• CPC Class Codes: B60R 22/28 incorporating energy-absorbing devices belt anchors provided with energy-absorbing means for protecting the occupants in case of physical contact therewith B60R21/055; belt retractors comprising energy-absorbing means B60R22/341, B60R22/4676

Abstract

A seat belt retractor includes a spool for winding a seat belt; a lock mechanism having a locking member for rotation with the spool in a normal state and for stop-rotation in a seat belt withdrawal direction in an emergency state; a torsion bar disposed between the spool and the locking member for absorbing energy of a passenger when the spool rotates in the seat belt withdrawal direction relative to the locking member in the emergency state; a stopper screwed in a shaft of the locking member to be movable in an axial direction along the shaft of the locking member when the spool rotates relative to the locking member; and an energy-absorption member disposed on one of the stopper and the locking member for deforming in a shear mode when the stopper moves in the axial direction along the shaft of the locking member.

Claims

1. A seat belt retractor for winding and unwinding a seat belt, comprising:

a spool for winding and unwinding the seat belt,

a locking mechanism having a locking member attached to the spool to be rotatable therewith in a normal state and capable of locking the spool in an emergency state,

a torsion bar disposed between the spool and the locking member for absorbing kinetic energy of a passenger when the spool rotates in a direction that the seat belt is withdrawn relative to the locking member in an emergency situation,

a stopper screwed in a shaft of the locking member to be movable in an axial direction along the shaft of the locking member when the spool rotates relative to the locking member, said stopper locking the spool not to rotate when the locking member locks the stopper not to move in the axial direction, and

an energy-absorption member disposed on one of the stopper and the locking member and situated between the stopper and the locking member for shear-deformation when the stopper moves in the axial direction along the shaft of the locking member.

2. A seat belt retractor according to claim 1, wherein said energy-absorption member has one of a column shape, prism shape, and tabular shape.

3. A seat belt retractor according claim 1, wherein said torsion bar and energy-absorption member are disposed separately.

4. A seat belt retractor according to claim 1, further comprising a cutter disposed on one of the stopper and the locking member for cutting the energy-absorption member when the stopper moves along the shaft of the locking member.

5. A seat belt retractor according to claim 4, wherein said cutter includes an edge having an acute angle.