SEAT BELT WARNING AND IGNITION INTERLOCK SYSTEM

• US 3,864,668 A
• Filed: 01/31/1973
• Issued: 02/04/1975
• Est. Priority Date: 01/31/1973
• Status: Expired due to Term

• Current Assignee: David Edward Bickford
• Original Assignee: David Edward Bickford
• Inventors: Bickford, David Edward
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/328,224
• Time in Patent Office: 734 Days
• Field of Search: 340/52E,278 180/82C 307/1SB 200/61.58B
• US Class Current: 180/268
• CPC Class Codes: B60R 2022/4816 for sensing locking of buckle
• CPC Class Codes: B60R 2022/4858 for sensing pressure on seat
• CPC Class Codes: B60R 2022/4891 preventing use of the vehicle when the seatbelt is not fastened
• CPC Class Codes: B60R 22/48 Control systems, alarms, or interlock systems, for the correct application of the belt or harness

Abstract

A seat belt warning and ignition interlock system including a capacitive occupant detector, a seat belt position sensor and a seat belt-occupant monitoring circuit functioning to provide a vehicle start disable signal and an alarm signal in response to a detected failure to achieve defined conditions relating to the position of a vehicle seat belt and the occupancy of the associated seat. The monitoring circuit produces a vehicle start disable signal if either an unoccupied seat has its associated seat belt buckled or if an occupant buckles his seat belt prior to occupying his seat in the vehicle.

Claims

1. In a seat belt warning system for vehicles an occupant detector means for detecting the presence of an individual seated on the vehicle seat comprising:

a variable capacitive means responsive to the presence of a seated occupant to assume a first value of capacitance and responsive to the absence of a seated occupant to assume a second value of capacitance;

means for producing a series of electrical pulses having a first predetermined rise time;

signal coincidence means having first and second inputs;

first circuit means for supplying said series of electrical pulses directly to a first input of said coincidence means; and

second circuit means including said variable capacitive means for supplying said series of electrical pulses to the second input of said coincidence means;

said second circuit means constructed to supply output pulses to said coincidence means having the same rise time as the pulses supplied through said first circuit means to the first input of said coincidence means when said variable capacitance means assumes its second value;

said second circuit means further constructed to alter the rise time of said pulses supplied to said coincidence means when said variable capacitive means assumes its first value;

said altered rise time of said pulses being different from said predetermined rise time;

said coincidence means responsive to the pulses supplied to its first and second input leads to provide an output of a first magnitude when said rise times are identical and to produce an output of a second magnitude when said rise times are different.

2. A seat belt warning system as in claim 1 comprising a third circuit means responsive to the fastening of said seat belt to generate a signal;

and monitoring means constructed to detect the sequence of occurrence of said signal of said second magnituDe from said coincidence means and the signal resulting from said fastening of said seat belt and to produce a signal enabling the operation of said vehicle in response to the occurrence of said signal of second magnitude followed by the occurence of said seat belt fastening signal.

3. In a seat belt warning system for vehicles an occupant detector means for detecting the presence of an individual seated on the vehicle seat comprising;

a variable capacitive means responsive to the presence of a seated occupant to assume a first value of capacitance and responsive to the absence of a seated occupant to assume a second value of capacitance;

means for producing a series of electrical pulses having a predetermined shape;

signal coincidence means having first and second inputs;

first circuit means for supplying said series of electrical pulses directly to a first input of said coincidence means; and

second circuit means including said variable capacitive means for supplying said series of electrical pulses to the second input of said coincidence means;

said second circuit means constructed to supply output pulses to said coincidence means having the same shape as the pulses supplied through said first circuit means to the first input of said coincidence means when said variable capacitance means assumes its second value;

said second circuit means further constructed to alter the shape of said pulses supplied to said coincidence means when said variable capacitive means assumes its first value;

said altered shape of said pulses being different from the shape of said pulses supplied to said coincidence means from said first circuit means;

said coincidence means responsive to the pulses supplied to its first and second input leads to provide an output of a first magnitude when said pulse shapes are identical and to produce an output of a second magnitude when said pulse shapes are different.

4. A seat belt warning system as in claim 3 comprising a third circuit means responsive to the fastening of said seat belt to generate a signal;

and monitoring means constructed to detect the sequence of occurrence of said signal of said second magnitude from said coincidence means and the signal resulting from said fastening of said seat belt and to produce a signal enabling the operation of said vehicle in response to the occurrence of said signal of second magnitude followed by the occurrence of said seat belt fastening signal.