US 4,023,746 AGranted

Belt retractor with winding prevention and memory mechanism

AssigneeGeneral Motors Corporation

InventorJoseph J. Magyar

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Abstract

A seat belt retractor according to the invention has a conventional inertia locking mechanism which permits the occupant to lean forwardly in the seat by unwinding belt from a reel which is biased in the winding direction by a winding spring. In accordance with the specific embodiment described, a winding prevention mechanism includes a ratchet connected to the reel and a pawl movably mounted on the housing for movement to a detenting position engaging the ratchet to block belt winding reel rotation and thereby hold the belt extended at a slackened condition about the occupant. A control disc and a blocking disc cooperate to control movement of the pawl to provide a belt retractor which prevents belt winding reel rotation to establish a slackened belt length, defines a first range of further unwinding movement during which progressive additional increments of belt slack is provided, defines a second range of further unwinding subsequent to which the belt is returned to a length within the first range, and is further effective to restore free belt winding reel rotation upon reel unwinding rotation beyond the limit of the second range.

Claims10

Dependent claims

In combination, an automotive vehicle having an occupant seat, a restraint belt for restraining the occupant in the seat, a reel having the belt wound thereon, a winding spring urging reel winding rotation to retract the belt to a stored position on the reel and pull the belt taut against the occupant when the belt is engaged in restraining position about the occupant, a locking mechanism effective to prevent belt extension only in response to a sensed acceleration condition so that the occupant may extend the belt for engagement in restraining position about the occupant and further extend the belt to permit leaning movement of the occupant in the seat by pulling the belt from the real against the winding spring, a detent mechanism effective when actuated to block winding rotation of the reel by the winding spring to hold the belt extended at its then length against the urging of the winding spring, and control means responsive to reel rotation induced by belt pull and urging of the winding spring and effective to control actuation of the detent mechanism such that the detent mechanism is actuated to hold the belt extended at a set condition of slackness with respect to the occupant upon predetermined sequence of reel rotation, and further effective to define the limits of a range of permissible further belt extension beyond the set condition of slackness as the occupant leans forwardly and to deactuate the detent mechanism during belt extension within the defined limited range to permit belt retraction by the winding spring as the occupant returns from the forwardly leaning position and then reactuate the detent mechanism when the belt is retracted to the length providing the set condition of slackness, said control means including means to deactuate the detent mechanism in response to reel rotation corresponding to belt extension beyond the defined limited range of permissible further extension whereby the urging of the winding spring pulls the belt taut against the occupant when the occupant returns from the forwardly leaning position and retracts the belt to stored position when released from engagement in restraining position.

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 detent mechanism effective when actuated to prevent belt winding reel rotation by the winding spring and relieve the tension on the belt to hold the belt extended at a set condition of slackness with respect to the occupant, disc means rotatably mounted and having a surface cooperably associated with the detent mechanism to control actuation of the detent mechanism, means for limiting rotation of the disc means to less than one revolution between one limit at which rotation of the disc means in the unwinding direction is stopped and another limit at which rotation of the disc means in the winding direction is stopped, friction clutch means acting between the disc means and the reel to rotate the disc means with the reel in both directions and allows the disc means to stop at the limits, the cooperable association between the disc means and the detent mechanism being such that upon belt unwinding rotation from the another limit of winding rotation of the disc means the detent mechanism is actuated over a first range of angular positions of the disc means to relieve belt tension by preventing winding reel rotation, and said cooperable association being such that upon further belt unwinding rotation the detent mechanism is deactuated over a second range of angular positions of the disc means so as to permit subsequent limited winding rotation of the reel and rotation of the disc means to within the first range of angular positions so as to again actuate the detent mechanism and relieve the belt tension, and means for deactuating and preventing the detent mechanism from being controlled within the first or second range of angular positions of the disc means during belt winding reel rotation subsequent to unwinding rotation to the one limit of unwinding rotation whereby the winding spring urges belt winding reel rotation and the belt is tensioned.

In an automotive vehicle having an occupant seat, a restraint belt for restraining the occupant in the seat, a reel having the belt wound thereon, a winding spring urging reel winding rotation to retract the belt on the reel and pull the belt taut against the occupant, and a locking mechanism effective to prevent belt extension only in response to a sensed acceleration condition so that the occupant may normally lean forwardly in the seat by extending the belt from the reel, the improvement comprising a one-way ratchet mechanism connected with the reel having a deactuated condition permitting free winding and unwinding reel rotation and an actuated condition permitting one-way unwinding reel rotation but preventing winding reel rotation by the winding spring to thereby relieve the urging of the winding spring acting upon the belt, a control mechanism for selectively actuating and deactuating the one-way ratchet mechanism and including first and second discs mounted for rotation relative the reel, means interconnecting the discs with the reel and the housing so that the reel rotates the discs within predetermined limits of rotation relative the housing, the discs cooperating upon initiation of belt extension subsequent to substantial belt retraction to actuate the one-way ratchet mechanism to block winding roatation of the reel at the urging of winding spring so that the belt may be positioned in slackened relation about the occupant, the one-way ratchet mechanism functioning during further unwinding rotation to introduce additional increments of slack in the belt, one of the discs having means defining a first limit of rotation and operating the one-way ratchet mechanism to deactuated condition upon unwinding reel rotation beyond the first limit so as to restore the urging of the winding spring until winding reel rotation returns the reel and the one disc to the first limit and the one-way ratchet mechanism is again actuated to relieve the urging of the winding spring so that the belt is restored to slackened relation about the occupant, one of the discs having means defining a second limit of unwinding rotation, the discs being effective upon unwinding reel rotation beyond the second limit to deactuate the one-way ratchet mechanism and maintain the deactuated condition upon belt winding reel rotation to and beyond the first limit of rotation whereby the urging of the winding spring is restored to the reel to retract the belt.

In combination, an automotive vehicle having an occupant seat, a restraint belt for restraining the occupant in the seat, a reel having the belt wound thereon, a winding spring urging 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 extension only in response to a sensed acceleration condition so that the occupant may normally lean forwardly in the seat by extending the belt from the reel, a ratchet wheel connected with the reel for rotation therewith and having ratchet teeth thereon, a pawl selectively engageable with the ratchet teeth to prevent belt winding reel rotation by the winding spring, a pair of disc members mounted for rotation with respect to the ratchet wheel and having peripheral surfaces characterized by radially extending portions effective to move the pawl into and out of engagement with the ratchet teeth upon disc member rotation and circumferentially extending portions allowing the pawl to dwell at the then attained position during disc member rotation, friction drive means interconnecting the disc members and the reel to rotate the disc members in response to reel rotation, the sequence of disc member rotatable by the friction drive means and the configuration of peripheral surfaces of the disc members being so arranged that in response to belt unwinding reel rotation as the occupant leans forwardly in the seat the pawl is engaged with the ratchet teeth to block belt retracting winding reel rotation but permit nonreversible progressive increments of belt slackening extension as the pawl ratchets over the ratchet teeth so as to introduce slack into the belt, at least one of the disc members having a radially extending portion which is effective to define the limit of such nonreversible increments of belt slackening extension by disengaging the pawl from the ratchet teeth, and a circumferentially extending portion on the at least one disc member allowing the pawl to dwell at the disengaged position until winding reel rotation by the winding spring retracts the belt and reversely rotates the at least one disc member so that the radially extending portion returns the pawl into engagement with the ratchet teeth whereby belt retracting winding reel rotation is blocked at the limit of belt slackening extension when the occupant returns from the forwardly leaning position.

In combination, an automotive vehicle having an occupant seat, a restraint belt for engagement in restraining position about the occupant to restrain the occupant in the seat, a reel having the belt wound thereon, a winding spring urging reel winding rotation to retract the belt on the reel and pull the belt taut against the occupant, a locking mechanism effective to prevent belt extension only in response to a sensed acceleration condition so that the belt may be extended for engagement in restraining position and the occupant may normally lean forwardly in the seat by extending 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, a first disc and a second disc mounted for rotation relative the reel and effective to control engagement and disengagement of the pawl with the ratchet wheel, means interconnecting the discs with the reel and the housing so that the reel rotation rotates the discs within predetermined limits of rotation relative the housing, the interconnecting means conditioning the first and second discs for control of the pawl upon belt winding reel rotation subsequent to the engagement of the belt in restraining position about the occupant, the first disc defining a first limit of unwinding reel rotation and being effective during unwinding reel rotation up to the first limit to allow engagement of the pawl with the ratchet wheel to block winding rotation of the reel by the winding spring to hold the belt against the urging of the winding spring in a slackened condition about the occupant, the first disc defining a second limit of rotation beyond the first limit and coacting with the pawl during rotation between the first and second limits of rotation to disengage the pawl from the ratchet wheel to permit winding rotation of the reel by the winding spring and then coacting to engage the pawl with the ratchet wheel when winding reel rotation returns the reel and the first disc to the first limit of rotation to thereby reestablish the slackened condition of the belt about the occupant, the first and second discs being effective upon unwinding reel rotation beyond the second limit of rotation to condition the pawl for capture by the second disc so that the pawl is maintained in disengagement upon belt winding reel rotation even beyond the first limit of rotation whereby the urging of the winding spring is restored to pull the belt taut against the occupant and retract the belt on the reel when disengaged from restraining position.

In a vehicle occupant restraint belt retractor having a belt reel rotatably supported on a housing, a belt wound and unwound from the reel during rotation in opposite directions, a locking mechanism for selectively locking the belt reel against belt unwinding reel rotation and a winding spring biasing the reel in the belt winding reel rotation direction, a winding prevention mechanism from selectively preventing belt winding reel rotation comprising:

a ratchet plate drivingly connected to the reel for rotation therewith and having ratchet teeth facing in the belt winding direction of rotation;
a pawl mounted on the housing for movement between a detenting position engaging one of the ratchet teeth to prevent belt winding reel rotation by the winding spring, a first undetenting position allowing normal biasing of the reel by the winding spring, and a second undetenting position;
a control disc having a peripheral edge engageable with the pawl for moving the pawl between detenting and undetenting positions, the control disc having a notch in the peripheral edge allowing movement of the pawl to detenting position engaging one of the ratchet teeth and a cam surface speed circumferentially from the notch and engageable with the pawl to move the pawl to the second undetenting position;
means rotating the control disc with the reel in response to belt unwinding reel rotation, means stopping control disc rotation when the cam surface of the control disc engages and moves the pawl to the second undetenting position;
means rotating the control disc with the reel in response to belt winding reel rotation, means stopping the control disc when the notch is aligned with the pawl;
blocking means operative to capture and hold the pawl in the second undenting position during belt winding reel rotation subsequent to belt unwinding reel rotation which causes the cam surfaces to move the pawl to second undetenting position, said blocking means releasing the pawl member from the second undetenting position upon subsequent belt unwinding reel rotation;
the control disc having a control surface extending between the notch and the cam surface in the belt winding reel rotation direction from the notch, the control surface holding the pawl in the first undetenting position during belt winding reel rotation subsequent to belt unwinding reel rotation insufficient to cause the cam surface to move the pawl to the second undetenting position thereby allowing rotation of the reel in the belt winding reel rotation direction until the notch is again aligned with the pawl to engage the pawl with the ratchet teeth and prevent rotation of the reel in the belt winding reel rotation direction by the winding spring.

4 more elements

In a vehicle occupant resistant belt retractor having a belt reel rotatably supported on a housing, a belt wound and unwound by the reel during rotation in opposite directions, a locking mechanism for selectively locking the belt reel against belt unwinding reel rotation, and a winding spring for biasing the reel in the belt winding direction of rotation, a winding prevention mechanism for selectively preventing winding rotation of the reel and comprising:

a ratchet plate drivingly connected to the reel for rotation therewith and having ratchet teeth facing in the belt winding direction of rotation;
a pawl mounted on the housing for movement between a detenting position engaging one of the ratchet teeth to prevent belt winding reel rotation by the winding spring, a first undetenting position allowing belt winding reel rotation by the winding spring, and a second undetenting position;
a control disc engageable with the pawl for moving the pawl between the detenting and undetenting positions, the control disc having progressively displayed on the peripheral edge thereof in the belt winding direction a notch, a control surface, and a cam surface;
means frictionally clutching the control disc with the reel in both directions to rotate the control disc with the reel in the belt unwinding direction to progressively move the pawl during belt unwinding rotation from the detenting position to the first undetenting position by engaging the control surface with the pawl and to the second undetenting position by engaging the cam surface with the pawl;
means for limiting rotation of the control disc to less than one revolution between one limit aligning the notch with the pawl to another limit engaging the cam surface with the pawl;
and
blocking means operative to capture and hold the pawl in the second undetenting position during belt winding reel rotation subsequent to belt unwinding rotation which causes the cam surface to move the pawl to second undenting position, said blocking means releasing the pawl member from the second undetenting position upon subsequent belt unwinding reel rotation, the control surface holding the pawl in the first undetenting position during belt winding reel rotation subsequent to belt unwinding reel rotation insufficient to cause the cam surface to move the pawl to second undetenting position thereby allowing return of the reel in the belt winding direction until the notch is again aligned with the pawl to engage the ratchet teeth and prevent wind up by the winding spring.

4 more elements

In a vehicle occupant restraint belt retractor having a belt reel rotatably supported on a housing, a belt wound and unwound by the reel during rotation in opposite directions, a locking mechanism for selectively locking the belt reel against belt unwinding reel rotation, and a winding spring for biasing the reel in the belt winding direction of rotation, a winding prevention mechanism for selectively preventing winding rotation of the reel and comprising:

a ratchet plate drivingly connected to the reel for rotation therewith and having ratchet teeth facing in the belt winding direction of rotation;
a pawl movably mounted on the housing and having a detenting position engaging one of the ratchet teeth to prevent belt winding reel rotation by the winding spring,
a control disc frictionally clutched to the reel for rotation therewith and having a control surface engageable with the pawl for controlling movement of the pawl between the detenting position and a first undetenting position and a cam surface controlling movement of the pawl between the first undetenting position and a second undetenting position;
means for limiting rotation of the control disc to less than one revolution between one limit with the pawl in detenting position and another limit with the pawl in second undetenting position;
a blocking disc frictionally clutched to the reel for rotation therewith and having a surface for engaging and holding the pawl in the second undetenting position;
said blocking disc and control disc cooperatively whereby upon substantial belt unwinding reel rotation of the belt reel to withdraw the belt for buckling about the occupant the cam surface of the control disc moves the pawl to the second undetenting position out of engagement with the ratchet teeth;
upon subsequent winding reel rotation of the belt reel by the winding spring the blocking disc acts to capture and hold the pawl in the second undetenting position;
upon subsequent belt unwinding reel rotation the blocking disc acting to release the pawl for movement to the detenting position and thereby prevent the winding effort of the winding spring from acting on the belt;
upon further belt unwinding reel rotation of the pawl being engaged by the control surface of the control disc to move the pawl to the first undetenting position preventing clicking of the pawl over the ratchet teeth and permitting subsequent belt winding reel rotation to rotate the control disc in the winding direction and disengage the control surface from the pawl to return the pawl to detenting position;
upon belt unwinding reel rotation beyond the extent of the control surface the cam surface engaging and moving the pawl to the second undetenting position;
and
upon subsequent belt winding rotation the pawl is held in the second undetenting position permitting belt winding reel rotation by the winding spring to complete winding of the belt on the reel.

9 more elements

In 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 freely extend the belt for engagement in restraining position about the occupant and further extend the belt to permit forward leaning movement of the occupant in the seat by pulling the belt from the reel against the bias of the winding spring, the improvement comprising;

a detent mechanism actuatable to block belt winding rotation of the reel by the winding spring to hold the belt extended at its then length against the urging of the winding spring;
and control means responsive to reel rotation induced by belt pull and the urging of the winding spring and effective to control actuation of the detent mechanism such that the detent mechanism remains unactuated during belt unwinding reel rotation induced by belt pull to extend the belt for engagement in restraining position about the occupant and remains unactuated during subsequent belt winding reel rotation by the winding spring to pull the belt taut against the occupant, said control means being effective upon subsequent belt unwinding reel rotation to actuate the detent mechanism to block belt winding and establish slack in the belt and define a first range of belt unwinding reel rotation during which the detent mechanism is actuated to provide progressive nonreversible increments of additional slack in the belt upon additional increments of belt unwinding by the occupant, said control means having a control surface for controlling actuation of the detent mechanism upon unwinding movement beyond the limit of the first range of belt unwinding and defining a second range of belt unwinding reel rotation during which the detent mechanism is temporarily unactuated so as to restore the urging of the winding spring to provide belt winding rotation of the reel to return the control means to within the first range so that the detent mechanism is again actuated to block belt winding and reestablish slack in the belt, and said control means having a further control surface for controlling actuation of the detent mechanism upon unwinding movement beyond the limit of the second range and effective upon unwinding reel rotation beyond the second range of unwinding defined by the control means to maintain the detent mechanism in an unactuated condition so that the winding spring urges winding of the belt to pull the belt taut against the occupant and wind the belt to the stored condition when released from engagement in the restraining position.

a plurality of circumferentially spaced ratchet teeth carried by the reel for rotation therewith and facing in the belt winding direction of rotation, a pawl selectively engageable with one of the ratchet teeth to prevent belt winding reel rotation by the winding spring;
and control means carried by the reel for rotation therewith in the belt winding direction induced by the winding spring and in the belt unwinding direction induced by pull on the belt, said control means being effective to provide an initial state of disengagement of the pawl and prevent engagement of the pawl with the ratchet teeth during a plurality of revolutions of the reel in the unwinding direction as the belt is extended for engagement in restraining position about the occupant and during subsequent rotation of the reel in the winding direction induced by the winding spring to pull the belt taut against the occupant, said control means having a control surface for controlling selective engagement of the pawl with one of the ratchet teeth upon belt unwinding rotation subsequent to belt winding rotation to prevent belt winding reel rotation by the winding spring but permit further belt unwinding by ratcheting of the pawl over the ratchet teeth so that the belt may be unwound to introduce additional nonreversible increments of slack into the belt, said control means having a memory control surface engaging the pawl upon unwinding rotation beyond a predetermined limit and defining a range of belt unwinding reel rotation during which the control surface holds the pawl out of engagement with the ratchet teeth so that the urging of the winding spring is restored to provide winding rotation of the reel and control means to within the predetermined limit so that the control surface again controls engagement of the pawl with one of the ratchet teeth, and said control means having another control surface effective to return the pawl to the initial state of disengagement upon unwinding reel rotation beyond the range of rotation defined by the memory control surface so that the winding spring urges winding of the belt taut against the occupant and stores the belt on the reel when the belt is disengaged from the restraining position.

Dependencies are inferred from the claim text.