Patent US4687274A successfully refreshed from Google Patents.
US4687274A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical contacts
Assignee: Massachusetts Institute of Technology
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Filing: 1984-05-10
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Granted: 1987-08-18
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Expires: 2004-05-10
Abstract
Abstract A pair of elements for providing slidable electrical contact therebetween wherein the contact surface of at least one of the elements comprises a plurality of contact portions and a plurality of depressed portions in between the contact portions so that wear particles which are generated between their contact surfaces as the elements are moved relative to each other are effectively swept from between the contact surfaces into the depressed portions where they are entrapped. Such operation tends to maintain a low electrical resistance between the elements over many cycles of use.
Inventors
- 👤 Nam P. Suh
- 👤 Nannaji Saka
- 👤 Ming J. Liou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:41
CPC Classifications
H; H01; H01R; H01R11/00; H01R11/01; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/325; H05K1/00; H05K1/02; H05K1/11; H05K1/117; H05K3/40; H05K3/4007
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
141 words
A pair of slidably contacting elements, a surface of at least one of said elements comprising a plurality of first contact portions and a plurality of second depressed portions, said contact portions forming island portions in between the valley portions formed by said depressed portions, said contact portions being in slidable contact with a contact surface of the other of said elements, the surfaces of said pair of elements which are in slidable contact being relatively moveable with respect to each other and the depressed portions of said at least one element entrapping substantially all of the wear particles generated at the contact regions between the contact portions of said at least one element and the contact surface of said other element during said relative movement by the movement of said wear particles from said contact regions into said depressed portions.
Claim 2
Dependent Claim
141 words
A pair of slidably contacting elements, a surface of at least one of said elements comprising a plurality of first contact portions and a plurality of second depressed portions, said contact portions forming island portions in between the valley portions formed by said depressed portions, said contact portions being in slidable contact with a contact surface of the other of said elements, the surfaces of said pair of elements which are in slidable contact being relatively moveable with respect to each other and the depressed portions of said at least one element entrapping substantially all of the wear particles generated at the contact regions between the contact portions of said at least one element and the contact surface of said other element during said relative movement by the movement of said wear particles from said contact regions into said depressed portions.
Claim 3
Dependent Claim
32 words
A pair of elements in accordance with claim 1 wherein said contact portions and said depressed portions are formed in an irregular pattern on the surface of said at least one element.
Claim 4
Dependent Claim
29 words
A pair of elements in accordance with claim 1 wherein the surface dimensions of said contact portions are less than the amplitude of the sliding motion between said elements.
Claim 5
Dependent Claim
26 words
A pair of elements in accordance with claim 1 wherein a pattern of said contact portions and said depressed portions are formed by a photo-resist process.
Claim 6
Dependent Claim
27 words
A pair of elements in accordance with claim 1 wherein a pattern of said contact portions and said depressed portions are formed by a mechanical embossing process.
Claim 7
Dependent Claim
33 words
A pair of elements in accordance with claim 1 wherein said contact portions and said depressed portions are formed in a substantially regular pattern on the surface of said at least one element.
Claim 8
Dependent Claim
23 words
A pair of elements in accordance with claim 6 wherein said contact portions and said depressed portions are each substantially rectangular in configuration.
Claim 9
Dependent Claim
23 words
A pair of elements in accordance with claim 7 wherein said contact portions and said depressed portions are each substantially square in configuration.
Claim 10
Dependent Claim
35 words
A pair of elements in accordance with claim 8 wherein said contact portions and said depressed portions are each about 100 μmeters square and said depressed portions each have a depth of about 100 μmeters.
Claim 11
Dependent Claim
20 words
A pair of elements in accordance with claim 1 wherein said contact portions include a contact surface layer of nickel.
Claim 12
Dependent Claim
24 words
A pair of elements in accordance with claim 10 wherein said contact surface layer is further coated with a layer of a lead-tin alloy.
Claim 13
Dependent Claim
25 words
A pair of elements in accordance with claim 11 wherein the thickness of said nickel layer is selected to provide a relatively low electrical resistance.
Claim 14
Dependent Claim
36 words
A pair of elements in accordance with claim 12 wherein said nickel layer is about 3.75 μmeters in thickness and said coating has a thickness within a range from about 0.1 μmeter to about 2.0 μmeters.
Claim 15
Dependent Claim
24 words
A pair of elements in accordance with claim 13 wherein said surface dimensions are at least an order of magnitude less than said amplitude.
References Cited (Backward Citations)
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 |