Adaptive load limiting retractor

US8220735B2 · kind B2 · utility

Assignee

• Autoliv ASP, Inc. · US

Inventors

• Bin Wang · Beijing, CN
• Frank Kiiskila · Leonard, US
• Daniel K. Webb · Oxford, US
• Jon E. Burrow · Ortonville, US
• Kurt Schulz · Lapeer, US
• Chad E. Moore · Rochester Hills, US
• Gerald Keller · Macomb Township, US

Key dates

• Filing date: Dec 22, 2009
• Grant date: Jul 17, 2012
• Expiry date: Sep 6, 2030

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60R2022/4642
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

An adaptive load limiting seat belt retractor particularly adapted for motor vehicle applications. The retractor provides multiple levels of load limiting through the use of a pair of internal torsion bar elements. The torsion bar elements control the tension force on the seat belt webbing during an impact in a manner which provides desirable crash management characteristics. The retractor can be switched between high and low load limiting modes through activation of a pyrotechnic pretensioner. When the pyrotechnic pretensioner is not activated, the retractor provides a low load level characteristic. Pretensioner activation switches the retractor into a high load level operating condition. A high load limiting level is provided when the pretensioner is not activated if the spindle rotation exceeds a limited level in the low load limiting condition. A degressive load limiting feature may be provided to cause load limiting to begin at a higher level than the high load limiting level, and then step down the high load limiting level.