Patent ID: 7934673

Claim:
A webbing take-up device comprising: a take-up shaft around which a webbing for restraining a passenger is wound such that the webbing can be taken up and pulled out; a frame rotatably supporting the take-up shaft; a motor; and a clutch that is mechanically intervened between the motor and the take-up shaft, transmits the rotation of the motor to the take-up shaft to cause the take-up shaft to rotate in the webbing take-up direction, and cuts off the transmission of rotation arising at the take-up shaft side to prevent that rotation from being transmitted to the motor, wherein the clutch includes a case that is fixed to the frame, a rotating body that is disposed coaxially with respect to the take-up shaft and rotates as a result of the rotation of the motor being transmitted to the rotating body, a ratchet that is integrally coupled to the take-up shaft, sliders that are configured to be relatively movable within a predetermined range with respect to the rotating body as a result of being retained in the case by frictional force, and lock bars that are disposed on the rotating body, are always biased in a direction in which the lock bars engage with the ratchet, and are ordinarily retained by the sliders in positions where the lock bars are disengaged from the ratchet, and when the rotating body rotates in the webbing take-up direction, the lock bars move away from the sliders such that the retention is released, engage with the ratchet by the biasing force, transmit to the ratchet the rotation of the rotating body in the webbing take-up direction, and allow the relative rotation of the ratchet with respect to the rotating body in the webbing take-up direction, and when the rotating body rotates in the webbing pullout direction, the lock bars move toward the sliders and are moved to and retained in the disengaged positions by the sliders.