Seat belt tension sensor with overload protection

• US 20030024326A1
• Filed: 06/19/2001
• Published: 02/06/2003
• Est. Priority Date: 06/19/2001
• Status: Active Grant

• Current Assignee: CTS Corporation
• Original Assignee: CTS Corporation
• Inventors: Lewis, John T., Broome, Randall, Kaijala, Murray, Blakesley, Patrick B., Rainey, Robert R.
• Granted Patent: US 6,647,811 B2
• Time in Patent Office: Days
• US Class Current: 73/862.391
• CPC Class Codes: B60R 2021/01272 Belt tensioners
• CPC Class Codes: B60R 21/0155 sensing belt tension
• CPC Class Codes: B60R 22/18 Anchoring devices
• CPC Class Codes: G01L 5/101 using sensors inserted into the flexible member
• CPC Class Codes: G01L 5/103 using sensors fixed at one end of the flexible member
• CPC Class Codes: G01L 5/108 for measuring a reaction force applied on a single support, e.g. a glider

Abstract

A seat belt tension sensor is attached to a seat belt in a vehicle. The seat belt tension sensor includes a housing attached between the vehicle and the seat belt. A limit structure is located in the housing. A sensor is attached to the limit structure for generating an electrical signal in response to the sensor being placed in tension. The electrical signal changes as a function of tension on the seat belt. The limit structure moves between a first position in which the limit structure transfers the seat belt tension to the sensor and a second position in which the limit structure transfers the seat belt tension to the housing.

Claims

1. A seat belt tension sensor for attachment to a seat belt in a vehicle comprising:

a) housing attached between the vehicle and the seat belt;

b) a limit structure located in the housing; and

c) a strain member attached to the limit structure, for generating an electrical signal in response to the member being placed in tension, the electrical signal changing as a function of tension on the seat belt, the limit structure movable between a first position in which the limit structure transfers the seat belt tension to the strain member and a second position in which the limit structure transfers the seat belt tension to the vehicle.

2. The seat belt tension sensor according to claim 1, wherein the limit structure further comprises:

a) the housing having a flange, the flange having a hole therethrough;

b) a seat belt plate having an aperture, the seat belt plate located over the flange; and

c) a fastener extending through the hole and the aperture, the fastener affixed to the vehicle.

3. The seat belt tension sensor according to claim 2, wherein the strain member has a plurality of strain sensitive resistors thereon.

4. The seat belt tension sensor according to claim 3, further comprising:

a) a channel located in the housing;

b) a spring located in the channel; and

c) a slot located in the housing, the strain member mounted in the slot, the spring pressing against the strain member.

5. A seat belt tension sensor for measuring the amount of tension in a seat belt in a vehicle, the seat belt having an attached seat belt plate that is attached to the vehicle with a fastener, the seat belt plate having a hole, the seat belt tension sensor comprising:

a) a housing having a flange, a channel and a slot;

b) a spring mounted in the channel;

c) a strain member mounted in the slot, the strain member generating an electrical signal in response to the seat belt being placed in tension, the electrical signal changing as a function of tension on the seat belt;

d) the seat belt plate mounted over the flange, the fastener extending through the flange and seat belt plate; and

e) the seat belt plate moveable between a first position in which the seat belt plate transfers the seat belt tension to the strain member through the spring and a second position in which the seat belt plate transfers the seat belt tension to the fastener.