US4782927A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electroviscous fluid-actuated devices
Assignee: BTG International Ltd
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Filing: 1987-05-04
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Granted: 1988-11-08
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Expires: 2007-05-04
Abstract
Abstract An electroviscous fluid actuated device, such as a clutch, comprises relatively rotatable electrode plates (10,11) defining a gap (12) therebetween of 2 mm to 5 mm width. An electroviscous fluid in the gap (12) becomes "solid" when a pulsating d.c. is applied to the plates. Slippage can be controlled by controlling the peak value of the pulsating d.c. The electroviscous fluid comprises a suspension of starch in silicone oil, having a ratio by weight of at least 1:1.
Inventors
- 👤 John L. Sproston
- 👤 Nigel G. Stevens
- 👤 Ian M. Page
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:55
CPC Classifications
C; C10; C10M; C10M171/00; C10M171/001; F; F16; F16D; F16D37/00; F16D37/008
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
60 words
An electroviscous fluid-actuated device comprising electrodes defining a gap therebetween, an electroviscous fluid in said gap, and means for applying a pulsating electrostatic field to the electroviscous fluid in said gap by connecting a direct current voltage source to said electrodes, said direct current voltage source being rapidly pulsed to repeatedly provide a plurality of direct current pulses per second.
Claim 2
Dependent Claim
60 words
An electroviscous fluid-actuated device comprising electrodes defining a gap therebetween, an electroviscous fluid in said gap, and means for applying a pulsating electrostatic field to the electroviscous fluid in said gap by connecting a direct current voltage source to said electrodes, said direct current voltage source being rapidly pulsed to repeatedly provide a plurality of direct current pulses per second.
Claim 3
Dependent Claim
21 words
A device according to claim 1 in which the electrical potential of the direct current voltage source is about 5 KV.
Claim 4
Dependent Claim
20 words
A device according to claim 1 in which the gap between the electrodes is between 2 mm and 5 mm.
Claim 5
Dependent Claim
31 words
A device according to claim 1, in which the electroviscous fluid comprises a suspension of particles in a liquid, the ratio by weight of particles to liquid being at least 1:1.
Claim 6
Dependent Claim
33 words
A device according to claim 1 in which the electroviscous fluid comprises a suspension of particles in a silicone fluid with the ratio by weight of particles to liquid being at least 1:1.
Claim 7
Dependent Claim
12 words
A device according to claim 5 in which said particles are hygroscopic.
Claim 8
Dependent Claim
20 words
A device according to claim 5 in which the viscosity of the silicone fluid is between 1 and 500 centistokes.
Claim 9
Dependent Claim
18 words
A device according to claim 7 in which the viscosity of the silicone fluid is about 350 centistokes.
Claim 10
Dependent Claim
23 words
A device according to claim 8, in which the ratio by weight of particles to silicone fluid is not substantially more than 1.8:1.
Claim 11
Dependent Claim
35 words
A device according to claim 1, in which the electrodes are defined respectively by two relatively rotatable members which are coupled together by said electroviscous fluid when said direct voltage is applied to said electrodes.
Claim 12
Dependent Claim
21 words
A device according to claim 1 in which the electrical potential of the direct current voltage source is about 2.5 KV.
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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) | 1991-11-08 | 1992-05-09 | 1992-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-08 | 1996-05-09 | 1996-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-08 | 2000-05-09 | 2000-11-08 | $7700.00 | Window Closed / Lapsed |