ELECTRONIC VEHICLE SEAT OCCUPANT SENSOR

• US 3,732,538 A
• Filed: 02/23/1972
• Issued: 05/08/1973
• Est. Priority Date: 02/23/1972
• Status: Expired due to Term

• Current Assignee: Arden G. Gillund, John A. Moretti
• Original Assignee: Arden G. Gillund, John A. Moretti
• Inventors: Gillund, Arden G., Moretti, John A.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/228,544
• Time in Patent Office: 440 Days
• Field of Search: 340/52R,52E,258,278 307/1SB
• US Class Current: 340/457.1
• 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 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 22/48 Control systems, alarms, or interlock systems, for the correct application of the belt or harness
• CPC Class Codes: H01H 35/003 Switches operated by other part of human body than hands push-button switches H01H13/16; slide switches H01H15/20; cord switches H01H17/10; other switches H01H19/16 and H01H21/26

Abstract

An electrical antenna system including first and second elements is embedded in the seat of a vehicle with the first element being coupled to the output of a controlled AC source which supplies thereto a controlled alternating signal. The second element of the antenna system is connected to the input of a high impedance dectector. A wire mesh capacitively coupled the two elements and the signal coupled from the first element to the second element is detected by the detector. When a human is in proximity to the wire mesh, the capacitance characteristic of the human capacitively loads the antenna to the vehicle chassis which decreases the signal input to the detector. An indicator is responsive to the output of the detector to provide an indication when the signal input to the detector decreases due to the presence of the human in the proximity of the wire mesh to indicate the presence thereof. Distributed multiple wire antennas with and without conductive wire mesh and single wire antenna systems are described.

Claims

1. A seat occupant sensor for a vehicle having a chassis serving as an electrical ground comprising, in combination, a first electrical conductor carried by the seat in an area normally occupied by the occupant;

a controlled AC source coupled to the first electrical conductor for supplying thereto an alternating signal;

a detector responsive to a signal applied to an input thereof for generating an output having a first state when the signal applied to the input has a magnitude greater than a predetermined threshold and having a second state when the magnitude is below the predetermined threshold;

a second electrical conductor carried by the seat in the area normally occupied by the occupant;

means connecting the second electrical conductor to the input of the detector; and

means for capacitively coupling the first and second electrical conductors to supply the alternating signal with a magnitude greater than the predetermined threshold to the input of the detector in the absence of an occupant, said means including a surface area carried by the seat in the area normally occupied by the occupant which is capacitively coupled to chassis ground by the occupant when near the surface area to decrease the magnitude of the alternating signal supplied to the input of the detector below the predetermined threshold, whereby the output of the detector is in the seconD state while the vehicle seat is occupied.

2. A seat occupant indicator for a vehicle having a chassis serving as an electrical ground comprising, in combination, a first electrical conductor embedded under the surface of the seat normally occupied by the occupant;

a controlled AC source coupled to the first electrical conductor for supplying thereto an alternating signal;

a detector responsive to a signal applied to an input thereof for generating an output having a first state when the signal applied to the input has a magnitude greater than a predetermined threshold and having a second state when the magnitude is below the predetermined threshold;

a second electrical conductor embedded under the surface of the seat normally occupied by the occupant;

means connecting the second electrical conductor to the input of the detector;

means for capacitively coupling the first and second electrical conductors to supply the alternating signal with a magnitude greater than the predetermined threshold to the input of the detector in the absence of an occupant, said means including a surface area embedded under the surface of the seat normally occupied by the occupant which is capacitively coupled to chassis ground by the occupant when near the surface area to decrease the magnitude of the alternating signal supplied to the input of the detector below the predetermined threshold; and

indicator means coupled to the high input impedance detector for providing an indication when the output thereof is in a second state so as to thereby indicate the presence of the vehicle seat occupant.

3. A seat occupant indicator for a vehicle having a chassis serving as an electrical ground reference comprising, in combination, a power source;

a first electrical conductor embedded under the surface of the seat normally occupied by the occupant;

a controlled AC source coupled to the first electrical conductor for supplying thereto an alternating signal when said AC source is connected to the power source;

a detector responsive to a signal applied to an input terminal thereof for generating an output when said detector is coupled to the power source, said output having a first state when the signal applied to the input terminal has a magnitude greater than a predetermined threshold and having a second state when the magnitude is below the predetermined threshold, the detector including at least one MOSFET having a gate electrode connected to the input terminal;

a second electrical conductor embedded under the surface of the seat normally occupied by the occupant;

means for connecting the second electrical conductor to the input terminal of the detector;

a wire mesh capacitively coupling the first and second electrical conductors to supply the alternating signal with a magnitude greater than the predetermined threshold to the input of the high input impedance detector in the absence of an occupant, the wire mesh including a surface area embedded under the surface of the seat normally occupied by the occupant which is capacitively coupled to the chassis ground by the occupant when near the surface area to decrease the magnitude of the alternating signal supplied to the input terminal of the detector below the predetermined threshold;

indicator means coupled to the detector for providing an indication when the output thereof is in the second state and said indicator means is coupled to the power source;

a pair of selectively coupled or decoupled seat belt members; and

seat belt member responsive switch means for coupling the AC source, the detector and the indicator means to the power source when the seat belt members are decoupled, whereby the indicator means provides an indication of the presence of the vehicle seat occupant upon his failure to couple the seat belt members.