US4688141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for electrostatically suspending a body or sample
Assignee: Office National d'Études et de Recherches Aérospatiales
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Filing: 1985-06-25
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Granted: 1987-08-18
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Expires: 2005-06-25
Abstract
Abstract A device for electrostatically suspending an electrically charged body coises at least two spherical electrodes serving simultaneously for capacitive position detection and electrostatic positioning control for the body.
Inventors
- 👤 Alain M. Bernard
- 👤 Jean-Paul L. Canny
- 👤 Pierre L. Touboul
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:15
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/13; G01P15/131; G01P15/125; H; H02; H02N; H02N13/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
96 words
A device for electrostatically suspending a sample of material comprising a sample carrying an electrostatic charge; at least two conductive spherical electrodes respectively fed by high voltages of opposite polarity; a conductive screen surrounding said sample and electrodes and brought to ground potential whereby the sample is submitted to a first force proportional to the square of the sample charge, a second force proportional to the product of the electrode voltages, a third force proportional to the product of the sample charge by the electrode voltage; and means for varying a voltage feed to the electrodes.
Claim 2
Independent Claim
96 words
A device for electrostatically suspending a sample of material comprising a sample carrying an electrostatic charge; at least two conductive spherical electrodes respectively fed by high voltages of opposite polarity; a conductive screen surrounding said sample and electrodes and brought to ground potential whereby the sample is submitted to a first force proportional to the square of the sample charge, a second force proportional to the product of the electrode voltages, a third force proportional to the product of the sample charge by the electrode voltage; and means for varying a voltage feed to the electrodes.
Claim 3
Dependent Claim
18 words
A device for electrostatically suspending a sample according to claim 1 wherein the sample electrostatic charge is positive.
Claim 4
Dependent Claim
56 words
A device for electrostatically suspending a sample according to claim 1 wherein the device further comprises a toroidal conductive electrode having its center at the mid-point of a line joining the centers of two of said spherical electrodes, said toroidal electrode being brought to a voltage having the same polarity as the charge of said sample.
Claim 5
Dependent Claim
101 words
A device for electrostatically suspending a sample as claimed in claim 1 comprising a differential transformer with a primary winding fed with alternating current and two secondary windings connected to the spherical electrodes via a circuit for superimposing sample position detection signals and sample positioning control signals to form a capacitive measuring bridge and to measure the differences in the capacitance coefficients between the sample and the electrodes, wherein electric lines connecting the electrodes to the transformer are triaxal cables with an inner sheathing connected to the mid-point of the secondary windings and an outer sheathing connected to the ground potential.
Claim 6
Dependent Claim
101 words
A device for electrostatically suspending a sample as claimed in claim 2 comprising a differential transformer with a primary winding fed with alternating current and two secondary windings connected to the spherical electrodes via a circuit for superimposing sample position detection signals and sample positioning control signals to form a capacitive measuring bridge and to measure the differences in the capacitance coefficients between the sample and the electrodes, wherein electric lines connecting the electrodes to the transformer are triaxal cables with an inner sheathing connected to the mid-point of the secondary windings and an outer sheathing connected to the ground potential.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-17 | 1991-02-16 | 1991-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-17 | 1995-02-16 | 1995-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-17 | 1999-02-16 | 1999-08-18 | $7700.00 | Window Closed / Lapsed |