Capacitive sensor apparatus for passenger presence detection

• US 7,434,481 B2
• Filed: 02/14/2007
• Issued: 10/14/2008
• Est. Priority Date: 09/14/2006
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Murphy, Morgan D., Hawes, Kevin J., Hinze, Lee R.
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US11/706,016
• Publication Number:
  US 20080066563A1
• Time in Patent Office: 608 Days
• Field of Search: 73862391- 82382, 737/80
• US Class Current: 73/862.391
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 7/06 by electrostatic action

Abstract

A capacitive sensor apparatus is disposed between the bottom cushion and frame of a seat. The sensor apparatus includes first and second mutually parallel rigid force translation plates biased apart by a set of springs, first and second conductor plates centrally affixed to inboard faces of the first and second force translation plates, and a control circuit responsive to the gap capacitance between the first and second conductor plates. The force translation plates are joined in a manner to maintain the conductor plates parallel to each other while permitting movement of either force translation plate relative to the other in a mutually perpendicular direction.

Claims

1. Sensor apparatus for detecting the presence of a passenger on a seat, comprising:

first and second rigid planar force translation plates disposed in said seat;

joining means for joining said force translation plates in a manner that maintains them substantially parallel to each other while permitting movement of either force translation plate relative to the other in a direction perpendicular to said force translation plates;

a set of springs disposed between said first and second force translation plates for exerting a bias force that biases said first and second force translation plates apart in said perpendicular direction;

first and second conductor plates centrally affixed to inboard faces of said first and second force translation plates, respectively; and

a control circuit responsive to a gap capacitance between said first and second conductor plates for detecting the presence of said passenger when a weight of said passenger overcomes the bias force of said springs.

2. The sensor apparatus of claim 1, where:

said first conductor plate is formed on first circuit board affixed to the inboard face of said first force translation plate; and

said second conductor plate and said control circuit are mounted on opposite sides of a second circuit board affixed to the inboard face of said second force translation plate.

3. The sensor apparatus of claim 2, where said control circuit is electrically coupled to said second conductor plate through said second circuit board, and the apparatus additionally comprises a conductive element electrically coupling said first conductor plate to said control circuit.

4. The sensor apparatus of claim 3, further where:

said control circuit is mounted on an outboard face of said second circuit board;

said conductive element is a flexible conductor; and

said flexible conductor passes through a slot aperture in said second force translation plate adjacent said second circuit board to reach said control circuit.

5. The sensor apparatus of claim 1, where:

said second force translation plate has a central opening with an interior ledge recessed in said opening; and

said control circuit is mounted on an outboard face of a circuit board disposed within said central opening and supported on said interior ledge.

6. The sensor apparatus of claim 5, where:

said second force translation plate has a slot aperture adjacent said central opening; and

said first conductor plate is electrically coupled to said control circuit by a flexible conductor that passes through said slot aperture.

7. The sensor apparatus of claim 5, where:

said second force translation plate includes an electrical connector for coupling said control circuit to a remote electronic module, and insert molded conductors coupled between said control circuit and said electrical connector.

8. The sensor apparatus of claim 7, where said insert molded conductors include a set of compliant pins that protrude from said interior ledge and pass through a margin of said circuit board.