Patent ID: 9539981
Date: 2017-01-10
CPC Classifications: B60R

Claim:
1. A seat belt retractor comprising: a spindle winding a webbing; an electric motor which generates power for rotating the spindle in a desired direction; a power transmission means including a clutch that enables transmission of the power of the electric motor to the spindle when the electric motor generates the power for rotating the spindle in a winding direction of the webbing, and also disables transmission of the power of the electric motor to the spindle when the electric motor generates a power in a direction opposite to the power for rotating the spindle in the winding direction; a control means which drives and controls the electric motor; and a drawing direction rotation detecting means which detects that the electric motor is rotating in a drawing direction of the webbing by measuring an electromotive force of the electric motor; wherein the control means in the course of drawing the webbing is operative to control the electric motor to rotate in the drawing direction of the webbing to release the clutch of the power transmission means, when driving power is not supplied to the electric motor and the drawing direction detecting means detects an electromotive force of the electric motor, the electromotive force being generated by drawing of the webbing by manual operation.