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US 4,134,026 AGranted
Mechanical switch circuit comprising contact conditioning means
AssigneeRicoh Company, Ltd.
InventorsKiyoshi Sone, Ichiro Yoshihara
Life of this patent
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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.
Claims14
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.
2 more elements
Dependencies are inferred from the claim text.