Patent ID: 8777147

Claim:
A seat belt device comprising: a spindle for retracting a seat belt; an electric actuator which generates a first force for rotating the spindle; a pre-tensioner which can be activated to generate a second force for rotating the spindle; and a power transmission mechanism which transmits the first force from the electric actuator to the spindle, wherein the power transmission mechanism is capable of reversibly switching connection and disconnection between the electric actuator and the spindle before the pre-tensioner is activated, while when the pre-tensioner is activated, the power transmission mechanism interrupts the connection between the electric actuator and the spindle, the power transmission mechanism including: a ratchet wheel which rotates together with the spindle; a pawl which moves in response to the rotation of the electric actuator; a cam member which restricts a movement of the pawl so that the pawl moves towards the ratchet wheel to bring the pawl into engagement with the ratchet wheel, when the pawl moves in response to the rotation of the electric actuator, and wherein when the pre-tensioner is activated, the pawl is caused to move in a direction in which the pawl moves away from the ratchet wheel by making use of the rotation of the ratchet wheel by the pre-tensioner, and the cam member is caused to move by the movement of the pawl to a position where the cam member is not capable of restricting the movement of the pawl.