Self leveling underground marker
US6380857B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 2000 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Oct 16, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2434
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The marker has a housing, an inner member and a tuned circuit. The housing has a spherical cavity therein. The inner member is located inside of the housing cavity and is rotatable therein. The tuned circuit has an inductance in the form of a coil as well as a capacitance. The tuned circuit is tuned to a particular frequency. A weight is coupled with the inner member and is eccentrically located within the spherical cavity. The eccentrically located weight seeks the lowest portion of the housing cavity. Thus, when the marker is manipulated so as to disorient the tuned circuit, the weight will rotate the inner member back to its stable position so as to properly orient the tuned circuit coil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.