US4134026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanical switch circuit comprising contact conditioning means
Assignee: Ricoh Co Ltd
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Filing: 1977-06-07
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Granted: 1979-01-09
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Expires: 1997-06-07
Abstract
Abstract Two reed switches are alternately closed by a magnet rotating with a shaft of a water meter or the like which is to be read remotely. A capacitor discharges through the reed switches when the same are closed, increasing the switch current without increasing the external power source current, thereby producing temporary partial fusion of the switch contacts and maximum contact effectiveness. A low-pass filter and a snap action circuit such as a Schmitt trigger are connected to the switches to eliminate the effects of contact bouncing and noise signals from the output of the circuit.
Inventors
- 👤 Kiyoshi Sone
- 👤 Ichiro Yoshihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:02
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/244; G01D5/24471; G01D5/24476; H; H01; H01H; H01H1/00; H01H1/60; H01H1/605
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
102 words
A switch circuit comprising: a D.C. power source having first and second ends; a first resistor, a second resistor and a first capacitor connected in series across the first and second ends of the power source in such a manner that the capacitor is connected between the first and second resistors; a second capacitor connected at a second end thereof to the second end of the power source; and a mechanical switch means for selectively connecting a first end of the second capacitor to first and second ends of the first capacitor which are connected to the first and second resistors respectively.
Claim 2
Dependent Claim
102 words
A switch circuit comprising: a D.C. power source having first and second ends; a first resistor, a second resistor and a first capacitor connected in series across the first and second ends of the power source in such a manner that the capacitor is connected between the first and second resistors; a second capacitor connected at a second end thereof to the second end of the power source; and a mechanical switch means for selectively connecting a first end of the second capacitor to first and second ends of the first capacitor which are connected to the first and second resistors respectively.
Claim 3
Dependent Claim
23 words
A switch circuit as in claim 1, further comprising a third capacitor connected across the first and second ends of the power source.
Claim 4
Dependent Claim
17 words
A switch circuit as in claim 1, further comprising a low-pass filter connected across the second capacitor.
Claim 5
Dependent Claim
70 words
A switch circuit as in claim 3, in which the low-pass filter comprises a third resistor and a fourth capacitor connected in series in such a manner that the third resistor is connected to the first end of the second capacitor and the fourth capacitor is connected to the second end of the power source, the third resistor and the fourth capacitor constituting a first stage of the low-pass filter.
Claim 6
Dependent Claim
75 words
A switch circuit as in claim 4, in which the low-pass filter further comprises a fourth resistor and a fifth capacitor connected in series in such a manner that the fourth resistor is connected through the third resistor to the first end of the second capacitor and the fifth capacitor is connected to the second end of the power source, the fourth resistor and the fifth capacitor constituting a second stage of the low-pass filter.
Claim 7
Dependent Claim
33 words
A switch circuit as in claim 1, further comprising a snap action circuit having an input connected between the first end of the second capacitor and the second end of the power source.
Claim 8
Dependent Claim
18 words
A switch circuit as in claim 6, in which the snap action circuit has a high input impedance.
Claim 9
Dependent Claim
17 words
A switch circuit as in claim 6, in which the snap action circuit comprises a Schmitt trigger.
Claim 10
Dependent Claim
18 words
A switch circuit as in claim 8, in which the Schmitt trigger comprises first and second cross-coupled inverters.
Claim 11
Dependent Claim
53 words
A switch circuit as in claim 8, in which the Schmitt trigger further comprises an integrating circuit connected between an output of the first inverter and an input of the second inverter, the snap action circuit further comprising an exclusive OR gate having inputs connected to outputs of the first and second inverters.
Claim 12
Dependent Claim
57 words
A switch circuit as in claim 1, in which the mechanical switch means comprises a first reed switch connected between the first end of the second capacitor and the first end of the first capacitor and a second reed switch connected between the first end of the second capacitor and the second end of the first capacitor.
Claim 13
Dependent Claim
29 words
A switch circuit as in claim 1, further comprising a sixth capacitor connected between the first end of the power source and the first end of the second capacitor.
Claim 14
Dependent Claim
31 words
A switch circuit as in claim 5, further comprising a seventh capacitor connected between the first end of the power source and a junction of the third resistor and fourth capacitor.
Claim 15
Dependent Claim
32 words
A switch circuit as in claim 13, further comprising an eighth capacitor connected between the first end of the power source and a junction of the fourth resistor and the fifth capacitor.
References Cited (Backward Citations)
US3541347A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-08 | 1982-07-10 | 1983-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-08 | 1986-07-10 | 1987-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-08 | 1990-07-10 | 1991-01-09 | $7700.00 | Window Closed / Lapsed |