Arrangement/function of seatbelt wear automatic comfort fit - GF91.40-P-1602A

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MODEL 140, 210

Emergency tensioning retractor unit is also equipped with seatbelt wear automatic comfort fit. Seatbelt wear automatic comfort fit reduces retraction and extension strength of automatic belt reel thus making seatbelt wear more pleasant for driver or passengers.

Basic components of seatbelt wear automatic comfort fit are:

Strong retractor spring (1)
Weak comfort spring (2)
Spring housing with external toothing
Left or right front seat belt comfort feature solenoid (K18/4, K18/5)
Left or right front seat buckle and seat belt wear convenience switch (S68/9 or S68/10)

Fig 1: Identifying Arrangement/Function Of Seatbelt Wear Automatic Comfort
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Function description

In normal state, weak comfort spring (2) is blocked through overriding power and is therefore inoperative. Strong retractor spring (1) acts on belt retractor axle and affects only retraction function. Spring housing turns with belt retractor axle in retraction direction.

With seatbelt buckled, left or right front seat belt comfort feature solenoid (K18/4, K18/5) is actuated via left or right front seat buckle and seat belt wear convenience switch (S68/9 or S68/10). Solenoid blocks spring housing via a pawl. Pawl locks in external toothing of spring housing, blocks turning movement of housing in retraction direction and thereby decouples strong retractor spring.

Weak comfort spring, blocked until now, now acts on belt retractor axle and comfort state is produced.

In comfort state, retraction and extension strength of automatic belt retractor is reduced by effect of weak spring depending on extension of belt.