Patent ID: 6827308
Filing Date: 2004-12-07
Classification: B60R

Abstract:
A control method of a seat belt retractor comprising:applying a webbing of a seat belt to an occupant and fastening a tongue to a buckle, automatically winding the webbing several times repeatedly with a predetermined interval therebetween for preventing looseness of the webbing on the occupant, determining whether a further winding of the webbing is needed to prevent the looseness of the webbing after a predetermined time from a last winding of the webbing, and if necessary, winding the webbing again, receiving at least one of signals selected from a state signal showing a movement of the occupant wearing the seat belt and an external signal obtained from detecting means installed in a vehicle during running thereof, controlling a rotation of a spool for the webbing by switching a rotational torque of a motor to a predetermined reduction ratio corresponding to at least one of the state signal and the external signal, or controlling a driving state of the motor to a predetermined torque, to thereby wind the webbing on the spool, winding the webbing when the tongue is disengaged from the buckle, and turning OFF a power source of a control circuit for operating the motor upon detection of a situation that winding of the webbing is accomplished or that the webbing has not been withdrawn for a predetermined period of time.