Assessment of Timely Lockup of Web-Sensing Restraint Retractors

This paper presents a review of web-sensitive locking retractors that are designed to prevent webbing payout of occupant restraint systems in emergency conditions. Investigation of the design and function of such devices reveals variables that affect their operation, which, when properly considered, allows the designer or user to assess their suitability in various applications.

A description of web-sensing locking retractors and an explanation of their theory of operation shows how design, manufacturing, and application variability can affect their desired performance. Changes to design, manufacturing methods and testing procedures, and reconfiguration of applications are considered to improve their reliability.