Seat occupancy switching device for motor vehicles

• US 5,164,709 A
• Filed: 09/18/1991
• Issued: 11/17/1992
• Est. Priority Date: 09/19/1990
• Status: Expired due to Fees

• Current Assignee: BMW AG (Bayerische Motoren Werke AG)
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Lamberty, Hans, Weishaupt, Walter
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US07/761,051
• Time in Patent Office: 426 Days
• Field of Search: 340/667, 340/457.1, 307/10.1, 180/273, 310/800
• US Class Current: 340/667
• 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: B60R 21/01516 using force or pressure sensing means

Abstract

A seat occupancy switching device for motor vehicles having a sensor responding to seat occupancy and an analysis circuit which emits a signal when a seat is occupied. The sensor is a lateral-force-sensitive cable which is arranged in the area of the seat surface. This cable provides a plurality of signal changes occurring continuously during seat occupancy. The analysis circuit registers each change of the sensor output signal as seat occupancy information. This analysis circuit includes a processor that receives the sensor output signal, and a monostable-circuit step.

Claims

1. A seat occupancy switching device for motor vehicles, comprising:

a sensor responding to seat occupancy, which, when a seat is occupied, emits a sensor output signal having a plurality of signal changes occurring continuously during seat occupancy, said sensor being a later-force-sensitive cable arranged in the area of a seat surface; and

an analysis circuit coupled to the sensor, the analysis circuit registering each change of the sensor output signal as seat occupancy information.

2. A switching device according to claim 1, wherein the cable is arranged at points of a seat surface which are subjected to the highest stress.

3. A switching device according to claim 2, wherein the cable is foamed into a seat body.

4. A switching device according to claim 3, wherein the cable contains a piezoelectric active material.

5. A switching device according to claim 2, wherein the cable contains a piezoelectric active material.

6. A switching device according to claim 1, wherein the cable contains a piezoelectric active material.

7. A switching device according to claim 1, wherein the cable is foamed into a seat body.