US3794850A - Device for reconditioning switch contacts - Google Patents

Device for reconditioning switch contacts Download PDF

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Publication number
US3794850A
US3794850A US3794850DA US3794850A US 3794850 A US3794850 A US 3794850A US 3794850D A US3794850D A US 3794850DA US 3794850 A US3794850 A US 3794850A
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United States
Prior art keywords
contact
fixed
movable contact
contacts
power supply
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Expired - Lifetime
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English (en)
Inventor
Y Hirose
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Nippon Gakki Co Ltd
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Nippon Gakki Co Ltd
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Publication of US3794850A publication Critical patent/US3794850A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/60—Auxiliary means structurally associated with the switch for cleaning or lubricating contact-making surfaces
    • H01H1/605—Cleaning of contact-making surfaces by relatively high voltage pulses

Definitions

  • ABSTRACT The so-called coherer effect is utilized for reconditioning the touching faces of a movable contact and a fixed break contact of each of several selector switches in a cascade connection.
  • power supply means Connected in series in a closed circuit formed by the movable contacts and the fixed break contacts of the selector switches is power supply means such that each time the movable contact'of any of the selector switches is returned to the break contact thereof from the corresponding make contact, the insulating oxide films or the like which may have been formed on the touching faces of the contacts are electrically ruptured by a sufficiently high voltage delivered from the power supply means.
  • SWITCH C K T SWITCH C K T SWITCH c K T SWITCH C KT TOn-Ic E PZMENZU TIME DEVICE FOR RECONDITIONING SWITCH CONTACTS BACKGROUND OF THE INVENTION invention is applicable, for instance, to a number of interconnected selector switches which are operable from the keyboards of an electronic organ or like musical instruments to cause conduction through the corresponding switching circuits connected between the tone generator circuit and the tone coloring circuit of the electronic musical instrument.
  • the aforesaid switching circuits are provided for the respective keys of the instrument. Their inputs are connected to the respective tone generators and their outputs to the common tone coloring circuit. Hence, when any of the switching circuits is rendered conductive by the depression of the corresponding key, an output signal from the corresponding tone generator is permitted to pass therethrough to the tone coloring circuit. In this manner the switching circuits function substantially as gate circuits.
  • Each of the switching circuits has a control input connected to the fixed make contact of each of the selector switches in a cascade connection, such that the movable contact of each selector switch is connected to the fixed break contact of the next switch.
  • the movable contacts of all the selector switches are normally held in touch with their respective break contacts, and only the movable contact of the selector switch at one extremity of the cascade connection is grounded.
  • Another object of the invention is to provide a device wherein the so-called coherer effect-produced between metals upon application of sufficiently high voltage is utilized to cause the breakdown of the insulating films which may be formed on the touching faces of switch contacts.
  • a further object of the invention is to provide a de vice such that the touching faces of the contacts of a number of interconnected switches can always be held in proper operative condition without use of any precious metals designed to prevent their oxidation, so that the switches can be manufactured inexpensively, and their service life greatly extended, by use of the device of this invention.
  • a still further object of the invention is to provide a device such that the voltage required to cause thecoherer effect is impressed to the touching contacts of the interconnected switches only when any one of these switches is operated, while only a negligible amount of current is permitted to flow through the contacts as long as all the switches are held inoperative.
  • this invention provides, in a switch of the type comprising a movable contact, a fixed break contact, and at least one fixed make contact to be connected to a desired circuit, a device forreconditioning the touching faces of the movable contact and the fixed break contact which comprises power supply means connected in series in a closed circuit formed by the movalbe contact and the fixed break contact.
  • the power supply means is adapted to rupture, by virtue of the coherer effect, the insulating films on the touching faces of the movable contact and the fixed break contact each time the movable contact is moved into touch with the fixed break contact.
  • the coherer effect itself has long been known to electricians.
  • the touching faces of a pair of contacts tend to become covered with insulating films, due for the most part to the oxidation of the metal of which the contacts are made.
  • these films are each from about 1 or 2 nanometers in thickness, the free electrons within the metals are capable of passing therethrough so that the films offer but little resistance to the passage of current.
  • the thickness of the films grows closer to 10 nanometers, hardly any current is permitted to pass therethrough so that the switch is no longer capable of functioning properly.
  • the reference numeral 10 gen erally designates a switch comprising two fixed contacts numeral a and 10b and a movable contact 100.
  • One of the fixed contacts, 10a is a make contact connccted to any desired circuit or device ll such for example as one of the switching circuits of an electronic organ or like keyboard instruments which operates each time'the corresponding key on the keyboards of V the electronic musical instrument is depressed, as hereinafter set forth in further detail in relation with the embodiment of FIG. 2.
  • the other fixed contact 10b is a break contact which is grounded via power supply means 12 adapted to rupture, by virtue of the above explained coherer effect, the insulating oxide films or the like which may be formed on the touching faces of the contacts 10b and 100.
  • the movable contact 100 of the switch is also grounded, so that a closed circuit is formed which-involves the contacts 10b and 100 and the power supply means 12.
  • the device of this invention briefly outlined above is adapted for reconditioning the contact faces of a series of selector switches used to control the operations of the aforementioned switching circuits of an electronic organ or like musical instruments.
  • Each of these switching circuits designated by the reference characters 11 to 11,, in FIG. 2, performs a switching function-each time the corresponding key of the electronic musical instrument is depressed.
  • the inputs 13 to 13,, of these switching circuits are connected to the respective tone generators, not shown, of the musical instrument, whereas their outputs 14, to 14,, are connected commonly to a terminal 1 which is to be connected to the input of a tone coloring circuit or the like also not shown in the drawing.
  • the switching circuits 11 to ll correspond to the respective keys of the musical instrument.
  • the switching circuit 11 for instance, is rendered conductive when the key C is depressed.
  • the other switching circuits Il ,...ll,, and 11, are made conductive when the keys C ,...B, and C are depressed, respectively. While these switching circuits may incorporate mechanical contacts, gate circuits making use of usual transistors or field-effect transistors are now employed in preference to such mechanical devices. 7
  • a series of selector switches 10, to 10, in cascade connection are also provided correspondingly to the respective keys of the electronic musical instrument.
  • All these selector switches are of identical construction, each comprising two fixed contacts and a single movable contact.
  • the movable contact 10 of the selector switch 10 only is grounded, and the fixed break contacts 10 to 10 of all the selector switches are connected to the movable contacts 10 to 10 of the. adjoining'selector switches.
  • the fixed make contacts 10 to l0, of the selector switches are connected to the control inputs of the respective switching circuits 11 to 11
  • the fixed break contact 10,,5'of the selector switch 10' is grounded via the power supply means 12 adapted as aforesaid to electrically rupture the insulating oxide films or the like which may be formed on the touching faces of the movable contacts It) to 10, and the fixed break contacts I0 to 10 of all the selector switches 10, to I0
  • the movable contact 10. and the fixed break contact 10 of the selector switches 10, and 10 at both extremities of the cascade connection are grounded, either directly or indirectly, a closed circuit is formed by the movable contacts 10, to 10,, and the fixed break contacts 10 to 10 of all the selector switches.
  • the power supply means 12 connected in series in this elosed circuit is composed of a series connection of a resistor'r having relatively low resistance, a parallel circuit of a capacitor C and a resistor R having relatively high resistance, and a DC powerfsupply E capable of producing a constant DC voltage.
  • the resistor r may have a resistance of about lOOohms, and the resistor R a resistance of about kilo-ohms.
  • the movable contact 10 of the selector switch 10 is caused automatically to return to the break contact 10 from the make contact 10 Thereupon the output voltage from the DC power supply E is delivered via the capacitor C and the resistor r to the fixed break contacts 10,, to and the movable contacts l0, to 10,, of the selector switches 10,, to 10, and thence to the ground.
  • the DC voltage impressed to the touching faces of the break contact 10 and movable contact 10 of the selector switch 10 is assumed to be sufficiently high to produce the coherer effect thereby rupturing the insulating oxide films or the like which may have been formed thereon.
  • the contacts 10 and 1020 are thus reconditioned for proper operation.
  • a device for reconditioning the touching faces of said movable contact and said fixed break contact comprising power supply means connected in series in a closed circuit formed by said movable contact and said fixed break contact, said power supply means being adapted to cause the electrical breakdown of insulating films on the touching faces of said movable contact and said fixed break contact each time said movable contact is returned to said fixed break contact from said fixed make contact.
  • each of said switches being of the type comprising a movable contact, a fixed break contact, and at least one fixed make contact to be connected to a desired circuit, said fixed break contact of each of said switches being connected to said movable contact of the next switch, a device for reconditioning the touching faces of said movable contact and said fixed break of each of said switches, comprising power supply means connected in series in a closed circuit formed by said movable contacts and said fixed break contacts of said switches, said power supply means being adapted to cause the electrical breakdown of insulating films on the touching faces of said movable contact and said fixed break contact of each of said switches each time said movable contact is returned to said fixed break contact from the corresponding fixed make contact.
  • said power supply means comprises a DC power supply capable of delivering a constant DC voltage, a parallel circuit of a capacitor and a resistor having relatively high resistance, said parallel circuit being connected in series with said DC power supply, and'a resistor having relatively low resistance connected in series with said parallel circuit.

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  • Keying Circuit Devices (AREA)
  • Electrophonic Musical Instruments (AREA)
  • Contacts (AREA)
US3794850D 1972-03-24 1973-03-22 Device for reconditioning switch contacts Expired - Lifetime US3794850A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47029942A JPS5118189B2 (enrdf_load_stackoverflow) 1972-03-24 1972-03-24

Publications (1)

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US3794850A true US3794850A (en) 1974-02-26

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Family Applications (1)

Application Number Title Priority Date Filing Date
US3794850D Expired - Lifetime US3794850A (en) 1972-03-24 1973-03-22 Device for reconditioning switch contacts

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US (1) US3794850A (enrdf_load_stackoverflow)
JP (1) JPS5118189B2 (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4678927A (en) * 1983-10-20 1987-07-07 Transformatoren Union Aktiengesellschaft Circuit arrangement for large power transformers
US4851707A (en) * 1987-07-16 1989-07-25 Lindsay Audiophyle Associates "Fritting" technique and apparatus for improving the sound of switches and connectors in audio circuits
US5258654A (en) * 1992-03-30 1993-11-02 Eaton Corporation Computer-checking of the position of a switch whose contacts where oxidized
AT15U1 (de) * 1993-03-11 1994-09-26 Elin Energieanwendung Belastungsbeschaltung
WO1996030917A1 (en) * 1995-03-24 1996-10-03 Abb Power T & D Company Inc. Low current binary input subsystem
WO1997028550A1 (en) * 1996-02-01 1997-08-07 Motorola Inc. Low power consumption switch interface circuit
US20050029096A1 (en) * 2003-07-10 2005-02-10 Helmut Maurer Method and electronic circuit for regenerating an electrical contact
US20050231876A1 (en) * 2004-04-05 2005-10-20 Fujitsu Ten Limited Apparatus for preventing corrosion of contact

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0640053U (ja) * 1992-10-30 1994-05-27 敏雄 熊谷 田の整地機

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2701965A (en) * 1946-12-31 1955-02-15 Sherman Alex Maintenance of conductivity in electrical distribution systems
US3029351A (en) * 1958-12-19 1962-04-10 Ibm Contact driver circuit
US3407310A (en) * 1965-10-07 1968-10-22 Teletype Corp Contact cleaning circuit
US3407311A (en) * 1965-12-13 1968-10-22 Teletype Corp Contact cleaning circuit

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5326241B2 (enrdf_load_stackoverflow) * 1973-05-30 1978-08-01

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2701965A (en) * 1946-12-31 1955-02-15 Sherman Alex Maintenance of conductivity in electrical distribution systems
US3029351A (en) * 1958-12-19 1962-04-10 Ibm Contact driver circuit
US3407310A (en) * 1965-10-07 1968-10-22 Teletype Corp Contact cleaning circuit
US3407311A (en) * 1965-12-13 1968-10-22 Teletype Corp Contact cleaning circuit

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4678927A (en) * 1983-10-20 1987-07-07 Transformatoren Union Aktiengesellschaft Circuit arrangement for large power transformers
US4851707A (en) * 1987-07-16 1989-07-25 Lindsay Audiophyle Associates "Fritting" technique and apparatus for improving the sound of switches and connectors in audio circuits
US5258654A (en) * 1992-03-30 1993-11-02 Eaton Corporation Computer-checking of the position of a switch whose contacts where oxidized
AT15U1 (de) * 1993-03-11 1994-09-26 Elin Energieanwendung Belastungsbeschaltung
WO1996030917A1 (en) * 1995-03-24 1996-10-03 Abb Power T & D Company Inc. Low current binary input subsystem
US5672919A (en) * 1995-03-24 1997-09-30 Abb Power T&D Company Inc. Low current binary input subsystem
WO1997028550A1 (en) * 1996-02-01 1997-08-07 Motorola Inc. Low power consumption switch interface circuit
US5729167A (en) * 1996-02-01 1998-03-17 Motorola, Inc. Low power consumption switch interface circuit
US20050029096A1 (en) * 2003-07-10 2005-02-10 Helmut Maurer Method and electronic circuit for regenerating an electrical contact
US7109721B2 (en) * 2003-07-10 2006-09-19 Robert Bosch Gmbh Method and electronic circuit for regenerating an electrical contact
US20050231876A1 (en) * 2004-04-05 2005-10-20 Fujitsu Ten Limited Apparatus for preventing corrosion of contact
US7362011B2 (en) * 2004-04-05 2008-04-22 Fujitsu Ten Limited Apparatus for preventing corrosion of contact

Also Published As

Publication number Publication date
JPS4896120A (enrdf_load_stackoverflow) 1973-12-08
JPS5118189B2 (enrdf_load_stackoverflow) 1976-06-08

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