US 6,311,571 B1 · Seat belt tension sensor

Abstract

A seat belt tension sensor has an anchor, a seat belt tension receiver, a moving arm force responder, and an arm sensor. The seat belt tension receiver applies force received from a seat belt to the moving arm force responder. The moving arm force responder is made of spring metal bent to have a base for receiving force and one or two arms that are urged to move by the received force. The arm sensor responds to the arm or arms by generating an electric signal. The anchor has an opening through which a seat belt, the seat belt tension receiver and the moving arm force responder pass. A cross member of the anchor spans the opening and withstands the large forces applied by the seat belt when the vehicle strikes an obstacle. An edge of the cross member is grooved to engage the base of the moving arm force responder in a way that provides low friction during flexing of the base. The base of the moving arm force responder operates as a low friction bearing for the movement of the seat belt tension receiver. A flexible suspension element made of spring metal operates as a second bearing and also operates as a preloading spring. In a preferred embodiment, the arm sensor comprises a semiconductor capacitance sensor responsive to the capacitance between two capacitor plates and two arms of a moving arm force responder.

Claims32

Dependent claims

In an occupant protection system of a vehicle of the type comprising processing means for deploying occupant protection means, a seat belt tension sensor comprising:

an anchor,
a force sensing means, and
a tension receiver, and wherein:
said anchor comprising a plate comprising an opening spanned by a cross member,
said tension receiver being adapted for receiving force from a seat belt, said tension receiver also being connected with said force sensing means for applying force thereto,
said force sensing means being connected with said cross member for applying force thereto,
said force sensing means being adapted for generating an electric signal responsive to said force received from said tension receiver when said force received from said tension receiver is in the range of zero to a predetermined force, said predetermined force being less than one thousand pounds, and including
means for protecting said force sensing means when said force received from said seat belt is greater than said predetermined force.

5 more elements

In an occupant protection system of a vehicle of the type comprising processing means for deploying occupant protection means, a seat belt tension sensor comprising:

an anchor, said anchor comprising a cross member,
a flexible member,
a tension receiver, and
sensing means for generating an electric signal for transmission to said processing means, and wherein:
said flexible member being connected with said cross member for applying force thereto,
said tension receiver being adapted for receiving seat belt tension,
said tension receiver being connected with said flexible member for applying thereto force derived from said seat belt tension,
said flexible member being responsive to said force received from said tension receiver by flexing, and
said electric signal being indicative of said flexing of said flexible member.

6 more elements

Dependencies are inferred from the claim text.

Seat belt tension sensor

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Seat belt tension sensor

Life of this patent

Abstract

Claims32