Belt retractor with winding prevention mechanism

In combination, an automotive vehicle having an occupant seat, a restraint belt for restraining an occupant in the seat, a reel having the belt wound thereon, a winding spring urging belt winding reel rotation to retract the belt on the reel and pull the belt taut against the occupant, a locking mechanism effective to prevent belt unwinding only in response to a sensed acceleration condition so that the occupant may normally lean forwardly in the seat by unwinding the belt from the reel, a ratchet wheel connected with the reel for rotation therewith, a pawl selectively engageable with the ratchet wheel to prevent belt winding reel rotation by the winding spring, spring means acting on the pawl and urging the pawl toward engagement with the ratchet wheel, a control member mounted for rotation with the reel and having a cam surface for controlling movement of the pawl into and out of engagement with the ratchet wheel in response to a predetermined sequence of rotation of the control member, said spring means going overcenter upon predetermined movement of the pawl away from engagement with the ratchet wheel so that the spring holds the pawl in a disabled condition irrespective of rotation of the control member to a position which would otherwise engage the pawl with the ratchet wheel, cam members on the control member adapted to operate the pawl to and from the disabled condition in response to predetermined reel rotation, a vehicle door hinged for movement between open and closed positions, and means responsive to movement of the door to the open position to operate the pawl to the disabled condition irrespective of the rotational position of the control member.

In combination, an automotive vehicle having an occupant seat, a restraint belt for restraining an occupant in the seat, a reel for storing the belt and having a winding spring urging belt winding reel rotation to retract the belt on the reel and tension the belt about the occupant, a locking mechanism effective to prevent belt extension only in response to a sensed acceleration condition so that the occupant may normally extend the belt for engagement in restraining position about the occupant and further extend the belt to permit forward leaning movement in the seat by unwinding the belt from the reel, a ratchet plate connected to the reel for rotation therewith, a pawl movable between a detenting position engaging the ratchet plate to prevent belt winding reel rotation by the winding spring and a range of undetenting positions allowing belt reel rotation by the winding spring, spring means acting on the pawl and normally urging the pawl toward the detenting position, said spring means going overcenter upon movement of the pawl to a furthest undetenting position so that the pawl is held in the furthest undetenting position, a control disc rotatably mounted on the reel and having a control surface engageable by the pawl for controlling movement of the pawl, means coacting between the disc and the pawl to limit rotation of the disc to less than one revolution between a limit in the unwinding direction and another limit in the winding direction, friction clutch means acting between the disc and the reel to rotate the disc with the reel in both directions and allow the disc to stop at the winding and unwinding limits during continued rotation of the reel to wind and unwind the belt, the configuration of the control surface of the disc being such that the pawl is held in undetenting position when the disc is stopped at the winding limit and upon subsequent belt unwinding rotation from the winding limit the pawl is released for movement to the detenting position by the spring to relieve belt tension by preventing winding reel rotation, said disc having a lifting cam surface for moving the pawl to the furthest undetenting position upon belt unwinding to the unwinding limit of rotation of the disc so that the spring goes overcenter and holds the pawl in the furthest undetenting position during subsequent winding reel rotation by the winding spring, and another cam surface on the control disc for returning the pawl from the furthest undetenting position when the disc reaches the winding limit of rotation.

In combination, an automotive vehicle having an occupant seat, a restraint belt for restraining an occupant in the seat, a reel for storing the belt and having a winding spring urging belt winding reel rotation to retract the belt on the reel and tension the belt against the occupant, a locking mechanism effective to prevent belt extension only in response to a sensed acceleration condition so that the occupant may normally extend the belt for engagement in restraining position about the occupant and further extend the belt to permit forward leaning movement in the seat by unwinding the belt from the reel, a ratchet plate connected to the reel for rotation therewith, a pawl movable between a detenting position engaging the ratchet plate to prevent belt winding reel rotation by the winding spring and first and second undetenting positions allowing belt winding reel rotation by the winding spring, spring means acting on the pawl and urging the pawl from the first undetenting position to the detenting position, said spring means going overcenter upon movement of the pawl between first undetenting and second undetenting positions so that the pawl is held in the second undetenting position, a control disc rotatably mounted on the reel and having a surface for controlling movement of the pawl, means for limiting rotation of the disc to less than one revolution between one limit in the unwinding direction and another limit in the winding direction, friction clutch means acting between the disc and the reel to rotate the disc with the reel in both directions and allow the disc to stop at the limits, the configuration of the surface of the disc being such that upon belt unwinding rotation from the winding limit of rotation of the disc the pawl is in detenting position over a first range of angular positions of the disc to relieve belt tension by preventing winding reel rotation, upon further belt unwinding rotation the pawl is moved to the first undetenting position over a second range of angular positions of the disc so as to permit subsequent limited winding rotation of the reel and rotation of the disc to within the first range of angular positions and return the pawl to the detenting position to thereby relieve the belt tension, and upon belt unwinding beyond the second range of angular positions and rotation of the disc to the unwinding limit the pawl is moved to the second undetenting position so that the spring goes overcenter and the pawl is held in the second undetenting position during subsequent belt winding reel rotation whereby the winding spring urges belt winding reel rotation and the belt tension is restored.