Retractor, Seat Belt: Operation

The standard inertia-type Emergency Locking Retractor (ELR) will allow the seat belt webbing to unwind from and wind onto the retractor spool freely unless and until a predetermined inertia load is sensed. The retractor has an internal inertia latch mechanism that will lock the retractor spool once the predetermined inertia load is sensed. Locking the retractor spool prevents the seat belt webbing from being extracted from the retractor and firmly restrains the occupant wearing the seat belt. The retractor spool is automatically unlatched once the loading of the retractor inertia mechanism and the seat belt are relieved.

The primary function of the switchable ELR to Automatic Locking Retractor (ALR) feature is to securely accommodate an infant or child booster seat in any seating position of the vehicle except the driver side front seat without the need for a self-cinching seat belt tip half latch plate unit or another supplemental device that would be required to prevent the seat belt webbing from unwinding freely from the retractor spool of an inertia-type ELR in situations where the minimum inertia locking threshold has not been achieved.

The locked mode of the ALR is engaged and the retractor is switched from operating as a standard inertia-type ELR by first buckling the combination lap and shoulder belt buckle. Then all of the shoulder belt webbing is pulled out from the retractor. Once all of the belt webbing is extracted from the retractor spool, the retractor will automatically become engaged in the pre-locked ALR mode and will make a light, audible clicking or ratchet-like sound as the shoulder belt is allowed to retract on the spool to provide an audible confirmation that the ALR mode is engaged. Once the ALR mode is engaged, the retractor will remain locked and the belt will remain tight around whatever it is restraining.

The retractor is returned to standard ELR (inertia) mode by unbuckling the combination lap and shoulder belt buckle and allowing the belt webbing to be almost fully retracted on the retractor spool. The ELR mode is confirmed by the absence of the light, audible clicking or ratchet-like sound as the belt webbing retracts. This mode will allow the belt to unwind from and wind to the retractor spool freely unless and until a predetermined inertia load threshold is sensed, or until the retractor is again switched to the ALR mode.