Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2006-10-10
2006-10-10
Hofsass, Jeffery (Department: 2612)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S438000, C340S665000, C340S666000, C701S045000, C346S040000, C280S734000, C177S144000, C361S312000, C073S862473
Reexamination Certificate
active
07119705
ABSTRACT:
The capacitance of a shielded capacitive load cell is determined so as to minimize the effect of stray or parasitic capacitance between the load cell and other objects including the shield. The load cell conductors are coupled across input and output terminals of an operational amplifier that is tied to a reference voltage. A constant current is applied to the load cell, and the resulting rate of change in voltage at the amplifier output is measured as a representation of the load cell capacitance. In a vehicle seat sensor application including an electromagnetic interference shield between the load cell and the seating surface, the amplifier output is coupled to the load cell electrode furthest from the shield, the amplifier maintains the other load cell electrode at a virtual reference voltage, and the shield is tied to the reference voltage.
REFERENCES:
patent: 4266263 (1981-05-01), Haberl et al.
patent: 4836033 (1989-06-01), Seitz
patent: 5142921 (1992-09-01), Stewart et al.
patent: 5189376 (1993-02-01), Roberge et al.
patent: 5878620 (1999-03-01), Gilbert et al.
patent: 6218632 (2001-04-01), McCarthy et al.
patent: 6275047 (2001-08-01), Zoellick et al.
patent: 6448789 (2002-09-01), Kraetzl
patent: 6499359 (2002-12-01), Washeleski et al.
patent: 6703845 (2004-03-01), Stanley et al.
patent: 6927678 (2005-08-01), Fultz et al.
patent: 6999301 (2006-02-01), Sanftleben et al.
patent: 2003/0009273 (2003-01-01), Stanley et al.
patent: 2004/0113634 (2004-06-01), Stanley et al.
patent: 2005/0231379 (2005-10-01), Sprecher et al.
patent: 34 28 699 (1986-02-01), None
patent: 37 21 113 (1989-01-01), None
patent: 0 381 596 (1990-08-01), None
European Search Report dated Jun. 15, 2006.
Cobb Gregory A.
Constable Robert K
Fortune Duane D.
Fultz William W.
Griffin Dennis P.
Funke Jimmy L.
Hofsass Jeffery
Walk Samuel J
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