US3876967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable resistor
Assignee: Illinois Tool Works Inc
•
Filing: 1973-10-31
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Granted: 1975-04-08
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Expires: 1993-10-31
Abstract
Abstract A variable resistor having a number of windings consisting of flat resistance strips which have been formed by etching or galvanic deposition is disclosed. The resistor has a thermally conductive base and an electrically insulating layer between the resistance strip and the base.
Inventors
- 👤 Klaus Friedrich Hehl
- 👤 Bernd Schenk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:16
CPC Classifications
H; H01; H01C; H01C10/00; H01C10/30; H01C10/38
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
96 words
A variable resistor comprising a thermally conductive base, an electrically insulating layer, a resistance unit comprising a number of resistance strips which have change-over spaces therebetween and which are coupled by said electrically insulating layer to said thermally conductive base, a slider having a contact which can be brought into contact with contact surfaces of the individual resistance strips, and an actuating means for said slider wherein said base has open areas in alignment with said changeover spaces so that short circuiting through said base due to electrical breakdown of said insulating layer is substantially eliminated.
Claim 2
Dependent Claim
96 words
A variable resistor comprising a thermally conductive base, an electrically insulating layer, a resistance unit comprising a number of resistance strips which have change-over spaces therebetween and which are coupled by said electrically insulating layer to said thermally conductive base, a slider having a contact which can be brought into contact with contact surfaces of the individual resistance strips, and an actuating means for said slider wherein said base has open areas in alignment with said changeover spaces so that short circuiting through said base due to electrical breakdown of said insulating layer is substantially eliminated.
Claim 3
Dependent Claim
21 words
A variable resistor according to claim 1 in which said resistance strips comprise a metal sheet secured onto said insulating layer.
Claim 4
Dependent Claim
25 words
A variable resistor according to claim 1 in which the material of said resistance strips contains more than 17 percent chromium and 7 percent nickel.
Claim 5
Dependent Claim
20 words
A variable resistor according to claim 1 in which said insulating layer is an insulating mat of fine glass fabric.
Claim 6
Dependent Claim
14 words
A variable resistor according to claim 1 in which said insulating layer comprises mica.
Claim 7
Dependent Claim
21 words
A variable resistor according to claim 1 in which said insulating layer comprises a composite material of mica and polyamide fibres.
Claim 8
Dependent Claim
31 words
A variable resistor according to claim 1 in which said thermally conducting base is a plate and said thermally conducting plate comprises slots which determine the heat distribution in said plate.
Claim 9
Dependent Claim
26 words
A variable resistor according to claim 1 in which said resistance strips are covered with a non-conducting, non-metallic layer, the contact surfaces, however, being left free.
Claim 10
Dependent Claim
19 words
A variable resistor according to claim 1 in which said contact surfaces are flat strips of chrome nickel steel.
Claim 11
Dependent Claim
73 words
A variable resistor according to claim 1 comprising a contact spring wherein said thermally conducting base is a heat removal plate, which at an edge thereof is bent at least partially upwards and inwards to form a guide and said slider is pressed upwards by said contact spring against said inwardly bent edge section and is pivotally mounted on the combination of said resistance strip and insulating layer and said heat removal plate.
Claim 12
Dependent Claim
41 words
A variable resistor according to claim 1 in which said thermally conducting base is constructed to be a supporting unit for installation purposes and said actuating means comprises a lever from which a contact spring carrying a sliding contact is formed.
Claim 13
Dependent Claim
75 words
A variable resistor according to claim 1 in which said resistance strips, said insulating layer and said thermally conducting base constitute a resistance plate, which is mounted at a distance from a supporting plate, said actuating means comprises a lever which is pivotally mounted on said supporting plate, and a contact spring comprising a sliding contact is held by said actuating lever, said contact spring being self-lockingly engaged in a recess of said actuating lever.
Claim 14
Dependent Claim
29 words
A variable resistor according to claim 1 comprising a separate heat conducting means wherein said resistance strips are thermally coupled to said heat conducting means by a hollow rivet.
Claim 15
Dependent Claim
23 words
A variable resistor according to claim 1 wherein said resistance strips are thermally coupled to said heat conducting means by a hollow rivet.
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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) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |