Ground tether continuity monitor
US4558309A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 27, 1983 |
| Grant date | Dec 10, 1985 |
| Priority date | — |
| Expiry date | Jun 27, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/52
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A monitor for sensing any break in electrical continuity between a body and earth when the body is coupled to earth by way of a grounding tether used to prevent build-up of static charges on such body. The monitor includes an oscillator circuit for generating A.C. output voltages which are adapted to actuate an alarm. Body capacitance and resistance are coupled by way of the tether across an impedance network either in the tuned circuit determining oscillator frequency or in the output load thereof whereby the resistance or inductance of the impedance network provides the path to ground for the body through its tether. With body capacitance and resistance components of the total impedance, variable elements in the impedance network are adjusted to diminish the circuit output voltage below the threshold voltage required to actuate the alarm when continuity exists while developing an output voltage level sufficient to actuate the alarm when a break in continuity occurs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.