Seat belt tension sensing apparatus

• US 6,520,032 B2
• Filed: 03/27/2001
• Issued: 02/18/2003
• Est. Priority Date: 03/27/2001
• Status: Expired due to Fees

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Fleming, William J., Resh, Robert E.
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US09/818,126
• Publication Number:
  US 20020139196A1
• Time in Patent Office: 693 Days
• Field of Search: 738/659, 738/623.93, 738/623.91, 738/623.31, 738/624.51, 738/624.6, 738/624.72, 738/27, 738/31, 318/280, 280/735, 280/806, 701/45, 242/385.3
• US Class Current: 73/862.472
• CPC Class Codes: B60R 2021/01317 monitoring seat belt tensiont
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: G01L 5/0047 measuring forces due to residual stresses

Abstract

Apparatus (10) includes first and second members (20, 22) that are connected to each other and pivotable relative to each other about an axis (46). A spring (120) biases the first member (20) to pivot in a first rotational direction relative to the second member (22). A seat belt (14) engages the first member (20) and urges the first member to pivot against the bias of the spring (120) in a second rotational direction as tension in the seat belt increases. The relative angular position of the first and second members (20, 22) changes in proportion to the amount of tension on the seat belt. The apparatus (10) also includes a sensor (24) for measuring the angular position of the first member (20) relative to the second member (22) and providing a signal corresponding to the angular position. The signal is proportional to the amount of tension in the seat belt (14).

Claims

1. Apparatus comprising:

a first member;

a second member connected to said first member, said first and second members being pivotable relative to each other about an axis;

biasing means that biases said first member to pivot in a first rotational direction relative to said second member about said axis;

a vehicle seat belt engaging said first member and urging said first member to pivot against the bias of said biasing means in a second rotational direction about said axis, opposite said first rotational direction, as tension in said seat belt increases to vary the relative angular position of said first and second members, said angular position of said first member changing in proportion to the amount of tension in the seat belt; and

measuring means for measuring the angular position of said first member relative to said second member, said measuring means providing a signal that corresponds to said angular position of said first member relative to said second member, said signal being proportional to the amount of tension in the seat belt.

2. Apparatus as defined in claim 1, wherein said first member comprises a first guide plate and said second member comprises a mounting plate, said first guide plate and said mounting plate each having a first end and an opposite second end, said first end of said first guide plate and said first end of said mounting plate being connected to each other and pivotable relative to each other about said axis, said mounting plate being connected to the vehicle, said measuring means measuring the angular position of said first guide plate relative to said mounting plate.

3. Apparatus as defined in claim 2, wherein said first member is connected to said mounting plate by a hinge.

4. Apparatus as defined in claim 2, wherein said second end of said first guide plate is connected to a second guide plate, said first guide plate being pivotable relative to said second guide plate about a second axis.

5. Apparatus as defined in claim 4, wherein said first guide plate is connected to said second guide plate by a hinge.

6. Apparatus as defined in claim 2, wherein said biasing means is positioned between said first guide plate and a vehicle surface, said biasing means having a first end engaging said vehicle surface and an opposite second end that engages a first surface of said first guide plate, said biasing means urging said first guide plate away from said vehicle surface in a first lateral direction which causes said first guide plate to pivot relative to said mounting plate in said first rotational direction, said seat belt engaging a second surface of said first guide plate, opposite said first surface of said first guide plate, said seat belt urging said first guide plate towards said vehicle surface in a second lateral direction, opposite said first lateral direction, which causes said first guide plate to pivot relative to said mounting plate in said second rotational direction as the tension in said seat belt increases.

7. Apparatus as defined in claim 6, wherein said second guide plate has a second end, opposite said first end, said second end of said second guide plate slidably engaging said vehicle surface and sliding along said vehicle surface when said first guide plate moves in said first and second lateral directions.

8. Apparatus as defined in claim 1, wherein said seat belt has a first end connected to a retractor and an opposite second end connected by an anchor to a vehicle in which said seat belt is installed, said apparatus further including a seat belt tongue connected to said seat belt between said first and second ends of said seat belt and a seat belt buckle connected to the vehicle, said seat belt buckle receiving said seat belt tongue and releasably locking said seat belt tongue in said seat belt buckle.

9. Apparatus as defined in claim 8, wherein said apparatus is positioned near the second end of said seat belt proximate the anchor.

10. Apparatus as defined in claim 1, wherein said first member comprises a first cross-member and a pair of first linkages, each of said first linkages having a first end and an opposite second end, said first end of one of said first linkages being connected to one end of said first cross-member, said first end of the other of said first linkages being connected to an opposite end of said first cross-member, said first linkages extending parallel to each other and perpendicularly from said first cross-member,

said second member comprising a second cross-member and a pair of second linkages, each of said second linkages having a first end and an opposite second end, said first end of one of said second linkages being connected to one end of said second cross-member, said first end of the other of said second linkages being connected to an opposite end of said second cross-member, said second linkages extending parallel to each other and perpendicularly from said second cross-member,

said apparatus further comprising a third cross-member that extends between and interconnects said second ends of said first and second linkages,

said first, second and third cross members extending parallel to each other, said first and second linkages being pivotable about said axis, said first and second cross-members being pivotable with said first and second linkages, respectively, about said axis, said axis extending through said third cross-member.

11. Apparatus as defined in claim 10, wherein said measuring means measures said angular position of said first linkages relative to said second linkages.

12. Apparatus as defined in claim 10, wherein said first cross-member, said third cross-member, and said first linkages define a first seat belt aperture, said second cross-member, said third cross-member, and said second linkages defining a second seat belt aperture, said seat belt extending through said first seat belt aperture in a first direction, around said third cross-member, and through said second seat belt aperture in a second direction, different than said first direction.

13. Apparatus as defined in claim 12, wherein the seat belt extends around said first and second cross-members in a first curved direction and around said third cross-member in a second curved direction, opposite said first curved direction.

14. Apparatus as defined in claim 13, wherein said first curved direction is generally clockwise and said second curved direction is generally counterclockwise.

15. Apparatus as defined in claim 13, wherein said first curved direction is generally counterclockwise and said second curved direction is generally clockwise.

16. Apparatus as defined in claim 13, wherein said biasing means urges said first and second linkages to form angles with each other, said seat belt undergoing lateral displacement by said first, second and third cross-members under the bias of said biasing means, said seat belt urging said first and second linkages against the bias of said biasing means, which reduces said lateral displacement as the tension in said seat belt increases.

17. Apparatus as defined in claim 13, wherein said seat belt has a first end connected to a retractor and an opposite second end connected by an anchor to a vehicle in which said seat belt is installed, said apparatus further including a seat belt tongue connected to said seat belt between said first and second ends of said seat belt and a seat belt buckle connected to the vehicle, said seat belt buckle receiving said seat belt tongue and releasably locking said seat belt tongue in said seat belt buckle.

18. Apparatus as defined in claim 17, wherein said tension sensing apparatus is positioned near said second end of said seat belt, proximate said anchor.

19. Apparatus as defined in claim 1, further comprising a controller operatively connected to said measuring means, said controller receiving said signal from said measuring means.

20. Apparatus as defined in claim 19, wherein said controller is operatively connected to an inflator for providing inflation fluid for inflating an inflatable vehicle occupant protection device, said controller preventing actuation of the inflator when said signal is at a predetermined level.

21. Apparatus as defined in claim 20, wherein said controller calculates the amount of tension in the seat belt, said controller preventing actuation of the inflator when the tension in the seat belt is at a predetermined level.

22. Apparatus as defined in claim 1, wherein said biasing means comprises a spring.

23. Apparatus comprising:

a first member having first and second ends;

a second member having first and second ends, said first end of said first member and said first end of said second member being pivotally connected to each other for pivotal movement about a common pivot axis;

biasing means that biases said first and second members to pivot about said pivot axis into a V-shape having a pair of legs comprising said first and second members extending at a first angle to each other and an apex, said pivot axis being at said apex, said second ends of said first and second members forming second and third angles with a reference surface;

a vehicle seat belt applying force to said first and second members at said apex, said force causing said second end of at least one of said first and second members to move relative to the second end of the other of said first and second members as tension in said seat belt varies and causing a change in said first, second and third angles, said first, second and third angles changing in proportion to the amount of tension in the seat belt; and

measuring means for measuring said change in at least one of said first, second and third angles, said measuring means providing a signal indicative of the amount of tension in the seat belt.