A belt relaxer for relaxing a seat belt or shoulder belt including a sensor in a seat, gear means which drive the belt reel in a direction to relax the belt, and linkage activating the gear means a predetermined distance in response to a signal from the sensor when an occupant of the seat applies pressure against the sensor, such as the back of the occupant resting or being supported by the back rest of the seat. The gear means is arranged so that upon release of pressure on the sensor and pushing the belt, or just release of pressure on the sensor, the gear means returns to initial position. The linkage is mechanical, electrical, pneumatic or hydraulic or combinations thereof. The sensor may include a time delay to avoid actuating the gear means upon momentary release and reapplication of pressure to the sensor. A number of embodiments are disclosed.
A seat belt retractor with a tension eliminator is provided with a ratchet wheel arrangement which acts as a position memory upon closing of a buckle switch and which is responsive to the belt webbing being drawn off the reel of the retractor by a seat occupant leaning forward beyond a predetermined distance, the wheel being rotated via an internal/planetary gear arrangement, proportionally to the excess distance whereupon the webbing can be retracted only said predetermined distance inducing a degree of tension eliminating slack in the webbing upon return of the occupant to the position in which he or she buckles the seat belt.
A seat belt retractor with a belt tension eliminator comprises a retractor shaft, a retracting spring, means producing a belt fastening signal, and a tension eliminator which prevents retraction of the belt with a measure of slack in the same, so that the tension or stress exerted on the body of the belt wearer by the belt fastened is eliminated by rendering the force of the retraction spring to be inactive in the normal driving position and posture assumed by the belt wearer.
A seat belt retractor with a tension eliminating mechanism comprises a reel on which a webbing is wound up when the reel rotates in one direction, first biasing means biasing the reel to rotate in the one direction, a ratchet wheel journaled on a concentric bearing portion formed on the reel, a toothed stopper arm for stopping rotation of the ratchet wheel when engaged with the same, second biasing means to bias the stopper arm to move in a direction to be disengaged from the ratchet wheel, an external gear journaled on an eccentric bearing portion formed on the reel, third biasing means to bias the ratchet wheel to rotate in the same direction as the one direction relative to the external gear, an internal gear stationarily mounted to the retractor and operatively engaged with the external gear, at least one stud fixed to the external gear, at least one arcuate slot formed in the ratchet wheel to be concentric with the same for spacedly receiving therein the stud, the stud and the slot being so arranged and formed that when the stud is in contact with one longitudinal end of the slot upon engagement of the toothed stopper arm with the ratchet wheel, the external gear becomes fixed so as to be prevented from rotation relative to the internal gear, and an electromagnet for bringing the toothed stopper arm into engagement with the ratchet wheel in response to buckling of the webbing by the passenger.
To provide for essentially uniform tension of a safety belt extended by a user from a belt supply, a roll-up motor is mechanically, serially connected to a spring housing which includes a spiral spring, to which one end thereof is attached, the other end of the spring being attached to the shaft of the belt roll-up unit. A traveling nut is threaded on the shaft of the roll-up unit, axial movement of which is sensed by a three-position switch which controls the motor to pay out more, or take up some belt if the tension on the belt does not fall within the tension as set by the spring and controlling a center-OFF position of the three-position switch. Roll-up operation of the motor is started by a current pulse supplied from a latch switch incorporated in the engaging latch of the belt and abruptly changing state upon disengagement of the belt from the latch.
An improved dual tension retractor mechanism for emergency locking safety belt retractors which allows application of main spring rewind bias without the necessity of an initial low tension belt rewinding. Application of the main spring rewind bias for belt retraction from low tension use mode is controlled independently of retractor reel winding or unwinding movements. The improvement includes a ratchet ring which is selectively rotatable relative said housing to allow reapplication of main spring rewind bias to the belt when the belt reel is in the low tension mode. Retractive rotation of the ratchet ring applies power rewind bias to the belt reel even though a bias blocking pawl remains engaged with the ratchet ring.
