Seat belt force sensor system

• US 20050082802A1
• Filed: 11/12/2004
• Published: 04/21/2005
• Est. Priority Date: 05/12/2000
• Status: Active Grant

• Current Assignee: Siemens Automotive Corporation (Siemens AG)
• Original Assignee: Siemens Automotive Corporation (Siemens AG)
• Inventors: Graf, Robert, Lichtinger, Harald, Curtis, Brian M.
• Granted Patent: US 7,234,729 B2
• Time in Patent Office: Days
• US Class Current: 280/735
• CPC Class Codes: B60R 2022/1806 for buckles
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0155 sensing belt tension
• CPC Class Codes: B60R 21/01556 Child-seat detection systems
• CPC Class Codes: B60R 21/33 Arrangements for non-electric triggering of inflation electrical circuits for triggering safety arrangements B60R21/01
• CPC Class Codes: B60R 22/16 using belts which become permanently deformed, i.e. one time use
• CPC Class Codes: B60R 22/18 Anchoring devices
• CPC Class Codes: G01L 5/103 using sensors fixed at one end of the flexible member

Abstract

A system for measuring seat belt forces is used to control deployment of vehicle airbags. The system includes a rigid plate member having one end attached to a portion of the seat belt and an opposite end mounted to a vehicle structure. The seat belt is used to secure passengers or an infant car seat to the vehicle seat. A sensor including a strain gage is mounted on the rigid plate between the ends and is used to measure the magnitude of forces exerted on the seat belt by the passenger or car seat. The strain gage generates a signal representative of the tension in the seat belt, which is used to control deployment of the airbag. The airbag is not deployed if the tension in the seat belt exceeds a predetermined limit.

Claims

1-19. -19. (canceled)

20. A sensor system for controlling airbag deployment comprising:

a rigid plate having a first end adapted to support a portion of a seat belt and a second end adapted for attachment to a vehicle structure;

a strain gage mounted on said rigid plate between said first and second ends for measuring the strain exerted on said rigid plate by a tension force applied to the seat belt; and

an electrical connector mounted to said rigid plate adjacent to said strain gage for receiving strain measurements from said strain gage and transmitting said measurements to a processor to determine the magnitude of the tension force wherein the processor generates a force signal representative of the magnitude of said tension force and wherein airbag deployment is controlled based on said force signal.

21. The sensor system according to claim 20 including an airbag adapted for mounting adjacent to a vehicle seat.

22. The sensor system according to claim 21 wherein said airbag does not deploy when said force signal exceeds a predetermined limit.

23. The sensor system according to claim 20 wherein said rigid plate includes a neck portion positioned between said first and second ends, said neck portion having a width that is less than a width of said first and second ends and wherein said strain gage is mounted on said neck portion.

24. The sensor system according to claim 23 wherein the vehicle structure is a B-pillar extending vertically adjacent to one side of a vehicle seat.

25. The sensor system according to claim 23 wherein the vehicle structure is a seat mount for a seat belt buckle latch mechanism.

26. The sensor system according to claim 25 wherein the seat belt includes a buckle strap for supporting a male buckle member and said seat belt buckle latch mechanism includes a female receptacle for receiving said male buckle member to securely latch an occupant to a vehicle seat with the portion of said seat belt extending between said male buckle member and said rigid plate.

27. The sensor system according to claim 23 wherein said electrical connector includes a main body portion for supporting at least one electrical component, said main body portion being directly mounted to said rigid plate between said strain gage and said second end.

28. The sensor system according to claim 27 wherein said main body portion comprises a rigid housing member and wherein said at least one electrical component comprises a microprocessor mounted within said rigid housing member.

29. The sensor assembly according to claim 28 wherein said first end of said rigid plate is positioned at an angle relative to said second end and said neck portion of said rigid plate.

30. The sensor system according to claim 20 including a printed circuit board supported by said electrical connector.

31. The sensor system according to claim 20 including an electronic control unit incorporated into said electrical connector.

32. A method for controlling airbag deployment comprising the steps of:

(a) providing a sensor assembly including a rigid plate having a first end adapted to support a seatbelt portion and a second end adapted for securement to a vehicle structure;

(b) mounting a strain gage to the rigid plate between the first and second ends;

(c) mounting an electrical connector to the rigid plate adjacent to the strain gage;

(d) measuring strain on the rigid plate due to seatbelt tension force with the strain gage; and

(e) controlling airbag deployment based on strain measured in step (d).

33. The method according to claim 32 including the step of mounting a printed circuit board to the electrical connector.

34. The method according to claim 32 including the step of mounting an electronic control unit to the electrical connector.

35. The method according to claim 32 including providing the electrical connector with a main body portion, supporting at least one electrical component on the main body portion, and directly mounting the main body portion to the rigid plate.

36. The method according to claim 35 wherein the main body portion comprises a rigid housing member and the at least one electrical component comprises a microprocessor and including mounting the microprocessor within the rigid housing member.

37. The method according to claim 32 wherein the rigid plate has a narrow neck portion interconnecting the first and second ends and wherein step (b) includes mounting the strain gage directly to the narrow neck portion.

38. The method according to claim 37 wherein step (c) includes mounting the electrical connector directly to the rigid plate between the strain gage and the second end.

39. The method according to claim 32 including not deploying an airbag when the strain exceeds a predetermined limit.