Belt spool retractor

• US 20050173581A1
• Filed: 02/09/2005
• Published: 08/11/2005
• Est. Priority Date: 02/10/2004
• Status: Active Grant

• Current Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Stevens, Bruce A.
• Granted Patent: US 7,424,986 B2
• Time in Patent Office: Days
• US Class Current: 242/374
• CPC Class Codes: B60R 2022/287 of torsion rods or tubes
• CPC Class Codes: B60R 2022/468 characterised by clutching means between actuator and belt reel
• CPC Class Codes: B60R 22/4633 Linear actuators, e.g. comprising a piston moving along reel axis and rotating along its own axis
• CPC Class Codes: B60R 22/4676 comprising energy-absorbing means operating between belt reel and retractor frame

Abstract

A seatbelt pretensioner mechanism (10) for use with a seatbelt retractor (11). The retractor (11) has a spool (16) configured for winding a seatbelt webbing thereon. The pretensioner mechanism (10) includes a movable actuator member (22) slidably coupled to the retractor spool (16), a stationary member (20) secured to the retractor (11) along a path of slidable movement of the movable member (22), and a base member (50) slidably coupled to the actuator (22) and to the stationary member (20). Helical splines (23) extend along a portion of the spool (16), and one or more complementary pins (25) extend along a first portion of the movable member (22) for slidingly engaging the splines (23) on the spool (16). Pins (28) also extend along a second portion of the movable member (22), and complementary helical splines (29) extend along a portion of the base member (50) for slidingly engaging the pins (28) on the second portion of the movable member (22). Activation of the pretensioner mechanism (10) produces a sliding movement of the movable member (22), thereby producing simultaneous sliding engagement between the groups of pins and helical splines. A coupling mechanism (80) restricts rotation of the base member (50) during sliding engagement between the splines and pins. Simultaneous sliding engagement between the complementary groups of helical splines produces a rotation of the spool (16) with respect to the stationary member (20), thereby pretensioning a seatbelt webbing wound on the spool (16).

Claims

1. A pretensioner mechanism for use with a seatbelt retractor comprising:

a rotatable member configured for rotating in a first direction to wind a seatbelt webbing thereon;

a movable member movable with respect to the rotatable member;

first and second complementary motion transmission elements, the first motion transmission element being secured along a portion of the movable member, the second motion transmission element being secured along a portion of the rotatable member, the second motion transmission element being configured for sliding engagement with the first motion transmission element;

a base member movable with respect to the movable member

complementary third and fourth motion transmission elements, the third motion transmission element being secured along a portion of the base member, the fourth motion transmission element being secured along a portion of the movable member, the fourth motion transmission element being configured for sliding engagement with the third motion transmission element;

at least one of the motion transmission elements having a helical configuration for producing relative rotation between the at least one motion transmission element and a complementary motion transmission element thereof upon sliding engagement therebetween; and

an engageable coupling mechanism for coupling the base member to a portion of the pretensioner mechanism that is substantially fixed with respect to the rotatable member, to substantially rotationally constrain the base member so as to substantially prevent rotation of the base member in a second direction opposite the first direction during sliding engagement between the third and fourth motion transmission elements.

2. The pretensioner mechanism of claim 1 wherein the coupling mechanism is engageable upon movement of the base member.

3. The pretensioner mechanism of claim 1 wherein the coupling mechanism is engageable upon activation of the pretensioner mechanism.

4. The pretensioner mechanism of claim 1 wherein the at least one of the motion transmission elements having a helical configuration is a helical groove.

5. The pretensioner mechanism of claim 4 wherein the motion transmission element complementary to the at least one of the motion transmission elements is a pin configured for sliding engagement with the helical groove.

6. The pretensioner mechanism of claim 1 wherein the motion transmission element complementary to the at least one of the motion transmission elements is a helical spline configured for sliding engagement with the helical groove.

7. The pretensioner mechanism of claim 1 wherein the movable member is detachably coupled to the rotatable member such that the movable member is movable in conjunction with the rotatable member.

8. The pretensioner mechanism of claim 1 wherein the base member is detachably coupled to the movable member such that the base member is movable in conjunction with the movable member.

9. The pretensioner mechanism of claim 1 wherein the coupling mechanism includes:

a first coupling element coupled to one of the stationary member and the base member; and

a second coupling element coupled to the other one of the stationary member and the base member, the second coupling element being configured to engage the first coupling element to substantially prevent rotation of the base member in the second direction.

10. The pretensioner mechanism of claim 1 further comprising another engageable coupling mechanism for coupling the rotatable member to a portion of the pretensioner mechanism that is substantially fixed with respect to the rotatable member, to substantially rotationally constrain the rotatable member so as to substantially prevent rotation of the rotatable member in a second direction opposite the first direction after pretensioning of the seatbelt.

11. A pretensioner mechanism for use with a seatbelt retractor comprising:

a rotatable member configured for winding a seatbelt webbing thereon;

a movable member coupled to the rotatable member, the movable member being movable with respect to the rotatable member; and

motion conversion means for converting motion of the movable member into rotational motion of the rotatable member in a first direction, thereby pretensioning a seatbelt webbing wound on the rotatable member.

12. The pretensioner mechanism of claim 11 wherein the motion conversion means comprises:

a first plurality of motion transmission elements, a first one of the first plurality of motion transmission elements being secured along a portion of the movable member, a second one of the first plurality of motion transmission elements being secured along a portion of the rotatable member, the second one of the first plurality of motion transmission elements being configured for sliding engagement with the first one of the first plurality of motion transmission elements, at least one of the first and second ones of the first plurality of motion transmission elements having a helical configuration for producing relative rotation between the at least one of the first and second ones of the motion transmission elements and the other of the first and second ones of the motion transmission elements upon sliding engagement therebetween.

13. The pretensioner mechanism of claim 11 wherein the rotatable member is rotationally coupled to the movable member so as to rotate in conjunction with the movable member, and wherein the motion conversion means comprises:

a base member substantially rotationally constrained so as to substantially prevent rotation of the base member in a second direction opposite the first direction during motion of the movable member; and

a first plurality of complementary motion transmission elements, a first one of the first plurality of complementary motion transmission elements being secured along a portion of the movable member, a second one of the first plurality of complementary motion transmission elements being secured along a portion of the base member, the second one of the first plurality of motion transmission elements being configured for sliding engagement with the first one of the first plurality of motion transmission elements,

at least one of the first and second ones of the first plurality of motion transmission elements having a helical configuration for producing relative rotation between the at least one of the first and second ones of the motion transmission elements and the other of the first and second ones of the motion transmission elements upon sliding engagement therebetween.

14. The pretensioner mechanism of claim 13 further comprising a stationary member substantially rotationally fixed with respect to the rotatable member so as to substantially prevent rotation of the stationary member with respect to the rotatable member;

and

wherein the base member is substantially rotationally constrained by a coupling means for coupling the base member to the stationary member.

15. The pretensioner mechanism of claim 13 wherein the movable member is rotationally coupled to the rotatable member by a second plurality of complementary motion transmission elements, a first one of the second plurality of complementary motion transmission elements being secured along a portion of the movable member, a second one of the second plurality of complementary motion transmission elements being secured along a portion of the rotatable member, the second motion transmission element of the second plurality being configured for sliding engagement with the first motion transmission element of the second plurality.

16. The pretensioner mechanism of claim 12 wherein the motion conversion means further comprises:

a base member substantially rotationally fixed with respect to the rotatable member so as to substantially prevent rotation of the base member with respect to the rotatable member; and

a second plurality of complementary motion transmission elements, a first one of the second plurality of complementary motion transmission elements being secured along a portion of the movable member, a second one of the second plurality of complementary motion transmission elements being secured along a portion of the base member, the second one of the second plurality of motion transmission elements being configured for sliding engagement with the first one of the second plurality of motion transmission elements.

17. The pretensioner mechanism of claim 16 wherein at least one of the first and second motion transmission elements of the second plurality of motion transmission elements have a helical configuration for producing relative rotation between the at least one of the first and second motion transmission elements of the second plurality and the other of the first and second motion transmission elements of the second plurality upon sliding engagement therebetween.

18. The pretensioner mechanism of claim 11 wherein the motion conversion means comprises:

a helical groove formed along a portion of one of the movable member and the rotatable member; and

a pin secured along a portion of the other of the movable member and the rotatable member, the pin being configured for sliding engagement with the helical groove to produce relative rotation between the pin and the groove upon sliding engagement therebetween.

19. The pretensioner mechanism of claim 11 wherein the motion conversion means is configured to convert motion of the movable member into approximately 1.25 rotations of the rotatable member.

20. A vehicle occupant restraint system comprising:

a seatbelt;

a belt retractor coupled to an end portion of the seatbelt, the retractor having a rotatable member configured for rotating in a first direction to wind a seatbelt webbing thereon;

a pretensioner mechanism coupled to the belt retractor to tension the seatbelt in the event of a collision, the pretensioner mechanism including;

at least one motion transmission element having a helical configuration, and

a coupling mechanism for coupling the rotatable member to a portion of the pretensioner mechanism that is substantially fixed with respect to the rotatable member, for substantially preventing rotation of the rotatable member in a second direction opposite the first direction.