| US 7,525,222 B2 | ||
| Sensor assembly and sensing system for sensing human tissue in a protected area of a machine | ||
| Robert E. Martinez, Austin, Tex. (US); Todd Goyen, San Antonio, Tex. (US); and Jack Nunes, Gilbraltor, Mich. (US) | ||
| Assigned to Federal - Mogul World Wide, Inc., Southfield, Mich. (US) | ||
| Filed on Dec. 05, 2005, as Appl. No. 11/293,943. | ||
| Prior Publication US 2007/0126291 A1, Jun. 07, 2007 | ||
| Int. Cl. H02H 11/00 (2006.01) | ||
| U.S. Cl. 307—326 [192/130] | 1 Claim |
| 1. A sensor assembly for use at a protected area of a machine, the sensor assembly comprising:
a power source producing a time-varying electric waveform;
an electrically conductive emitter plate disposed adjacent to the protected area, electrically connected to the power source,
and operating to generate a time-varying electric field within the protected area in response to application of the time-varying
electric waveform from the power source to the emitter plate;
plural electrically conductive sensor plates disposed adjacent to the protected area for receiving the time-varying electric
field and producing respective electrical signals that vary in response to changes in the electric field;
plural meters, each electrically connected to a respective one of the sensor plates, to measure a respective displacement
current of the electrical signal produced at the respective sensor plate; and
a signal analyzer electrically connected to the plural meters to monitor the respective displacement currents measured by
the plural meters to find an average displacement current, sensing a disturbance in one of the displacement currents, and
comparing the sensed displacement current disturbance to the average displacement current to determine whether the sensed
displacement current disturbance is indicative of human tissue within the protected area.
|