Patents
US 8878515 B1: Constant current metal detector
- Granted
- 2014-11-04
- Filed
- 2011-09-19 application 13235916
- Type
- Utility · 17 claims
- Elsewhere
- Google Patents ↗ · USPTO patent document ↗ · USPTO Patent Center record ↗
Abstract
A constant current is provided to an energizing coil in a magnetic detector by charging a capacitor through a resistor from a high voltage source. Discharging of the capacitor into the energizing coil quickly increases current in the energizing coil. After the capacitor is switched off, a low voltage source maintains current constant in the energizing coil. The coil discharges its energy as a negative voltage to the capacitor. A high negative voltage source tops off the capacitor. After a delay, the capacitor discharges a negative current into the energizing coil. A negative low voltage source maintains the negative current. The negative voltage source is disconnected, and the coil discharges positive voltage into the capacitor. The high voltage source tops off the capacitor with positive voltage to repeat the cycle.
Source: PVGPATDIS, file of 2026-04-10 (ipg141104.xml).
Assignees
| Assignee | Type | Place | Also on furp.org | Source |
|---|---|---|---|---|
| White's Electronics, Inc. 9 patents | US company or organization | Sweet Home, OR | PVGPATDIS, file of 2026-04-10 |
Inventors
| Inventor | Place | Patents | Person page | Source |
|---|---|---|---|---|
| John L. Earle | Sweet Home, OR | 5 | PVGPATDIS, file of 2026-04-10 |
CPC categories
| Subclass | Category | First group | Source |
|---|---|---|---|
| G01N | Investigating or analysing materials by determining their chemical or physical properties | G01N27/80 | PVGPATDIS, file of 2026-04-10 |
| G01V | Geophysics; gravitational measurements; detecting masses or objects; tags | G01V3/10 | PVGPATDIS, file of 2026-04-10 |
Cooperative Patent Classification, as currently assigned (one row per subclass).
Assignments and security interests
| Recorded | What | From | To | Reel/frame | Source |
|---|---|---|---|---|---|
| 2022-03-01 | Assignment Assignment of assignor's interest | WHITE'S ELECTRONICS, INC. signed 2020-10-16 | GARRETT ELECTRONICS, INC. GARLAND, TX | 59129/659 | ECORSEXC, file of 2026-09-25 |
| 2011-09-20 | Assignment Assignment of assignor's interest | EARLE, JOHN L. signed 2011-09-19 | WHITE'S ELECTRONICS, INC. SWEET HOME, OR | 26931/465 | ECORSEXC, file of 2026-09-25 |
Documents recorded with the USPTO Assignment Recordation Branch that list this patent. A security interest is a lender’s claim on the patent as collateral; a release ends it.
USPTO bulk data: PatentsView granted patents, disambiguated (PVGPATDIS) for patents, assignees, inventors, places and CPC categories; the USPTO Patent Assignment Dataset (ECORSEXC) for assignments and security interests. Patents filed in the last 20 years. No claims or full text. Links to other records are by name (and state): EXACT means the identical full name and state; FUZZY means a looser name match, with the confidence shown.