Seat Belt Retractor: Description and Operation

Emergency Locking Retractor (ELR)
The retractors in all seat positions feature ELR. During any period of sudden deceleration, or under torsional load when cornering at speed, a sensor weight within the safety belt retractor moves a locking pawl against the teeth on the retractor reel, which then locks the retractor preventing any further release of webbing. As soon as the load applied onto the retractor through the safety belt webbing is removed the locking pawl releases the retractor reel and normal movement is returned to the retractor.

Automatic Locking Retractor (ALR)
Automatic Locking Retractors (ALR) retractors are installed in all passenger seat positions. The safety belt webbing on these are clearly marked to show their operating feature. The ALR feature is initiated by pulling all of the webbing from the retractor with the buckle fastened, when the webbing is then released as it retracts the retractor locks allowing travel in only one plane thus producing a fixed length restraint and preventing the safety belt from introducing slack, making any child seat it may be restraining insecure. The ALR mode of the retractor is disengaged by allowing the unfastened webbing to fully retract on to the reel.