Method and apparatus for sensing seat occupancy

In a vehicle seat occupancy detection system that includes a seat for an occupant:

• a seating cushion for an occupant's seat, having a substantially horizontal upper surface portion and a lower portion;
• a sensor device having first and second relatively movable parts being aligned for relative movement substantially perpendicular to said seat cushion surfaces, said first part being mounted within said seat cushion and spaced below said upper surface, said second part also being mounted within said seat cushion and being spaced below said first part;
• said sensor device being operative to produce signals indicative of the distance between said first and second parts;
• and
• a processor for receiving said sensor signals and interpreting the signals to produce an output to indicate the presence of an occupant in said seat.

A method of detecting an occupant in a seat comprising the steps of:

• providing a seating cushion having a substantially horizontal upper surface portion function as an occupant's seating surface and a lower portion with an outer surface in substantial opposition to said upper surface;
• providing a weight sensor device having first and second relatively movable parts aligned for relative movement substantially perpendicular to said seat cushion surfaces, wherein said sensor device is operative to produce signals indicative of the distance between said first and second parts;
• mounting said first part of said sensing device internal to said seat cushion spaced below said upper surface;
• mounting said second part of said sensing device below said first part;
• and
• providing a means for receiving said sensor signals and interpreting said signals to produce an output to indicate the presence of an occupant in said seat.