Seatbelt webbing lock preventing apparatus

The invention is related to a seatbelt webbing lock preventing apparatus (1) enables a flywheel (22) constituted as an inertia mass means to prevent a rotating lock of a lock mechanism (9) followed by the webbing acceleration and deceleration of a scatbelt in any case of withdrawing the seatbelt from a retractor and rewinding it therein. The webbing lock preventing apparatus comprises a webbing control portion (10) including a locking portion (8) with a torsion bar mechanism (7) for limiting a force applied to a seatbelt, a locking actuation mechanism (9) provided with a flywheel (22) for controlling the operating of the locking portion and stopping the rotating of a spool (4) and the webbing of the seatbelt in accordance with the webbing acceleration and deceleration of the seatbelt caused by withdrawing the scatbelt from the retractor and rewinding it thereinto; and a flywheel rotating control portion including a friction spring (33) mounted in a hub of the locking actuation mechanism, thereby preventing the flywheel from being rotated with its inertia force at the time of the acceleration or deceleration of the webbing.