Seat belt retractor

Claim 2

A seat belt retractor comprising: a housing; a take-up shaft rotatably mounted to said housing; a spring means for biasing said take-up shaft in a belt retracting direction of retracting a seat belt; a gear mechanism operatively coupled to said take-up shaft; a tensionless mechanism operatively coupled to said gear mechanism and operable to prevent said take-up shaft from rotating in said belt retracting direction;

Claim 3

a motor actuated slack control mechanism operatively coupled to said gear mechanism and operable to rotate said take-up shaft; and means for controlling operation of said tensionless mechanism and said motor actuated slack control mechanism.

Claim 4

a motor actuated slack control mechanism operatively coupled to said gear mechanism and operable to rotate said take-up shaft; and means for controlling operation of said tensionless mechanism and said motor actuated slack control mechanism.

Claim 5

A seat belt retractor as claimed in claim 1, wherein said gear mechanism comprises a planetary gearing which includes a sun gear nonrotatably mounted on said take-up shaft, a ring gear rotatably mounted on said take-up shaft and a planet pinion meshing with said sun gear and said ring gear; said tensionless mechanism is operable to prevent said planet pinion from orbiting in the same direction as said belt retracting direction of said take-up shaft; and said motor actuated slack control mechanism meshes with said ring gear and is operable to rotate said ring gear.

Claim 6

A seat belt retractor as claimed in claim 2, wherein said tensionless mechanism includes a memory wheel serving as a carrier for said planet pinion and having a projection, a ratchet wheel rotatably mounted to said take-up shaft and having a projection, means for biasing said projection of said memory wheel into engagement with said projection of said ratchet wheel, a stopper lever movable to engage with said ratchet wheel, and a solenoid means for attracting said stopper lever into engagement with said ratchet wheel.

Claim 7

A seat belt retractor as claimed in claim 2, wherein said controlling means comprises a microcomputer including a sensor means for generating an output signal indicative of running state of a vehicle and a microcomputer including a ROM which stores a program wherein a desired slack is determined in response to said output signal.

Claim 8

In a vehicle having a seat having a seat adjustable mechanism, a seat belt retracting comprising a housing, a take-up shaft rotatably mounted to said housing, a spring means for biasing said take-up shaft ina belt retracting direction of retracting a seat belt, a planetary gearing including a sun gear nonrotatably mounted to said take-up shaft, a ring gear rotatably mounted to said take-up shaft and a planet pinion meshing with said sun gear and said ring gear, a tensionless mechanism operable to prevent said planet pinion from orbiting in the same direction as said belt retracting direction of said take-up shaft, a motor actuated slack control mechanism meshing with said ring gear and operable to rotate said ring gear; a sensor means for generating an output signal indicative of running state of the vehicle; a control unit operative connected to said tensionless mechanism and said motor actuated slack control mechanism, said control unit including means for determining a desired slack of the seat belt in response to said output signal, and means for controlling said motor actuated slack control mechanism in such a manner as to reduce a deviation from said desired slack.

Claim 9

In a vehicle having a seat having a seat adjustable mechanism, a seat belt retracting comprising a housing, a take-up shaft rotatably mounted to said housing, a spring means for biasing said take-up shaft ina belt retracting direction of retracting a seat belt, a planetary gearing including a sun gear nonrotatably mounted to said take-up shaft, a ring gear rotatably mounted to said take-up shaft and a planet pinion meshing with said sun gear and said ring gear, a tensionless mechanism operable to prevent said planet pinion from orbiting in the same direction as said belt retracting direction of said take-up shaft, a motor actuated slack control mechanism meshing with said ring gear and operable to rotate said ring gear; a sensor means for generating an output signal indicative of running state of the vehicle; a control unit operative connected to said tensionless mechanism and said motor actuated slack control mechanism, said control unit including means for determining a desired slack of the seat belt in response to said output signal, and means for controlling said motor actuated slack control mechanism in such a manner as to reduce a deviation from said desired slack.