Patent US3871944A successfully refreshed from Google Patents.
US3871944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integral composite element useful in electrostatic clutch or brake devices
Assignee: 3M Co
•
Filing: 1973-06-11
•
Granted: 1975-03-18
•
Expires: 1993-06-11
Abstract
Abstract An integral laminar composite semiconductive element having a highly conductive surface is provided by a layer of semiconductive particles and a layer of metal particles. The layers are integrated with and bonded together by a hard nonconductive thermoset bonding resin. The semiconductive element is especially useful in electrostatic clutch or brake devices such as those utilizing the Johnsen-Rahbek effect.
Inventors
- 👤 Mario Dominguez-Burguette
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:02
CPC Classifications
F; F16; F16D; F16D63/00; F16D63/002; B; B32; B32B; B32B15/00; B32B15/04; B32B15/08; B32B27/00; B32B27/42; H; H02; H02N; H02N13/00; B32B2311/00; B32B2311/02; B32B2311/04; B32B2311/06; B32B2311/08; B32B2311/12; B32B2311/16; B32B2311/24; B32B2311/30; Y; Y10; Y10T; Y10T428/00; Y10T428/21; Y10T428/213; Y10T428/26
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
119 words
AN INTEGRAL COMPOSITE ELEMENT HAVING A HIGHLY ELECTRICALLY CONDUCTIVE SURFACE AND A SEMICONDUCTIVE SURFACE, SAID ELEMENT BEING ESPECIALLY SUITED FOR USE IN ELECTROSTATIC BRAKE OR CLUTCH DEVICES, COMPRISING A FIRST LAYER OF BONDED PARTICULATE SEMICONDUCTIVE MATERIAL AND A SECOND LAYER OF BONDED PARTICULATE HIGHLY CONDUCTIVE METAL, SAID METAL BEING SOLID AT ROOM TEMPERATURE AND CAPABLE OF PROLONGED EXPOSURE TO AN AMBIENT ATMOSPHERE WITHOUT APPRECIABLE REDUCTION IN ELECTRICAL CONDUCTANCE, SAID PARTICULTE SEMICONDUCTIVE MATERIAL AND SAID PARTICULATE METAL BEING BONDED TOGETHER WITH A QUANTITY OF THERMOST RESING SUFFICIENT TO PROVIDE AN INTEGRAL, SELFSUPPORTING, HANDLEABLE, RIGID ARTICLE BUT NOT SUFFICIENT TO ELECTRICALLY ISOLATE EITHER THE METAL PARTICLES OR THE SEMICONDUCTIVE PARTICLES IN THEIR RESPECTIVE LAYERS AND AT THE INTERFACE BETWEEN THE LAYERS.
Claim 2
Dependent Claim
119 words
AN INTEGRAL COMPOSITE ELEMENT HAVING A HIGHLY ELECTRICALLY CONDUCTIVE SURFACE AND A SEMICONDUCTIVE SURFACE, SAID ELEMENT BEING ESPECIALLY SUITED FOR USE IN ELECTROSTATIC BRAKE OR CLUTCH DEVICES, COMPRISING A FIRST LAYER OF BONDED PARTICULATE SEMICONDUCTIVE MATERIAL AND A SECOND LAYER OF BONDED PARTICULATE HIGHLY CONDUCTIVE METAL, SAID METAL BEING SOLID AT ROOM TEMPERATURE AND CAPABLE OF PROLONGED EXPOSURE TO AN AMBIENT ATMOSPHERE WITHOUT APPRECIABLE REDUCTION IN ELECTRICAL CONDUCTANCE, SAID PARTICULTE SEMICONDUCTIVE MATERIAL AND SAID PARTICULATE METAL BEING BONDED TOGETHER WITH A QUANTITY OF THERMOST RESING SUFFICIENT TO PROVIDE AN INTEGRAL, SELFSUPPORTING, HANDLEABLE, RIGID ARTICLE BUT NOT SUFFICIENT TO ELECTRICALLY ISOLATE EITHER THE METAL PARTICLES OR THE SEMICONDUCTIVE PARTICLES IN THEIR RESPECTIVE LAYERS AND AT THE INTERFACE BETWEEN THE LAYERS.
Claim 3
Dependent Claim
24 words
The composite element of claim 1 wherein said metal is selected from the group consisting of gold, silver, platinum, iron, aluminum, copper, and tin.
Claim 4
Dependent Claim
14 words
The composite element of claim 1 where the semiconductive matErial is a phthalein-fluoran polymer.
Claim 5
Dependent Claim
17 words
The composite element of claim 1 wherein the semiconductive layer is from 0.3 to 1.2 mm thick.
Claim 6
Dependent Claim
21 words
The composite element of claim 1 wherein the semiconductor material comprises from about 70-97 percent by weight of the semiconductive layer.
Claim 7
Dependent Claim
14 words
The composite element of claim 1 wherein the thermoset resin is a phenol-aldehyde resin.
Claim 8
Dependent Claim
13 words
The composite element of claim 1 wherein said metal is pulverized reduced iron.
Claim 9
Dependent Claim
13 words
The composite element of claim 1 in the shape of a flat disc.
References Cited (Backward Citations)
US2273770A
Cited
US2923390A
Cited
US3002596A
Cited
US3240306A
Cited
US3343636A
Cited
US3655609A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |