Patent US4667147A successfully refreshed from Google Patents.
US4667147A
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Inductive proximity switch
Assignee: Siemens AG
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Filing: 1986-04-01
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Granted: 1987-05-19
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Expires: 2006-04-01
Abstract
Abstract This invention concerns an inductive proximity switch having an oscillator and a resonant circuit which is dampable by outside objects, as well as an electronic switch controllable by the voltage across the resonant circuit. From the signal of the electronic switch a switching hysteresis is derived. A device for changing the frequency, when the resonant circuit is damped, as a function of the signal of the electronic switch allows the adjustment of the hysteresis in such a way that there is essentially no effect on the sensitivity of the oscillator.
Inventors
- 👤 Bernhard Wiesgickl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:45
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/94; H03K17/945; H03K17/95; H03K17/952; H03K17/9537; H03K17/954
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
72 words
An inductive proximity switch having a resonant circuit dampable by external objects, an oscillator connected across said resonant circuit, and an electronic switch controllable by a voltage across said resonant circuit; an output signal of said electronic switch providing a switching hysteresis characteristic, said proximity switch further comprising a frequency changing device connected to the oscillator when the resonant circuit is damped, as a function of the signal of the electronic switch.
Claim 2
Dependent Claim
72 words
An inductive proximity switch having a resonant circuit dampable by external objects, an oscillator connected across said resonant circuit, and an electronic switch controllable by a voltage across said resonant circuit; an output signal of said electronic switch providing a switching hysteresis characteristic, said proximity switch further comprising a frequency changing device connected to the oscillator when the resonant circuit is damped, as a function of the signal of the electronic switch.
Claim 3
Dependent Claim
29 words
A proXimity switch according to claim 1, wherein the oscillator is a phase-locked-loop circuit including a voltage controlled oscillator portion which can be switchably controlled to a different frequency.
Claim 4
Dependent Claim
21 words
A proximity switch according to claim 1, wherein the switch to a different frequency is controlled by switchably connecting a resistance.
Claim 5
Dependent Claim
21 words
A proximity switch according to claim 2, wherein the switch to a different freguency is controlled by switchably connecting a resistance.
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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) | 1990-05-18 | 1990-11-17 | 1991-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-18 | 1994-11-17 | 1995-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-18 | 1998-11-17 | 1999-05-19 | $7700.00 | Window Closed / Lapsed |