US2812406A - Electrical contact - Google Patents

Electrical contact Download PDF

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Publication number
US2812406A
US2812406A US413633A US41363354A US2812406A US 2812406 A US2812406 A US 2812406A US 413633 A US413633 A US 413633A US 41363354 A US41363354 A US 41363354A US 2812406 A US2812406 A US 2812406A
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US
United States
Prior art keywords
percent
alloy
gold
contacts
group
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US413633A
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English (en)
Inventor
Thomas F Egan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE536121D priority Critical patent/BE536121A/xx
Priority to NL92647D priority patent/NL92647C/xx
Priority to NL193594D priority patent/NL193594A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US413633A priority patent/US2812406A/en
Priority to FR1118924D priority patent/FR1118924A/fr
Priority to DEW15742A priority patent/DE1078774B/de
Priority to GB5701/55A priority patent/GB765273A/en
Application granted granted Critical
Publication of US2812406A publication Critical patent/US2812406A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B32B15/018—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of a noble metal or a noble metal alloy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/021—Composite material
    • H01H1/023—Composite material having a noble metal as the basic material

Definitions

  • This invention relates generally to electrical contacts and more particularly to electrical contacts used to make and break circuits wherein circuit interruptions due to malfunctioning of contacts must be kept to a minimum.
  • An object of this invention is to reduce to a minimum circuit interruptions due to contact failure.
  • a further object of this invention is to improve circuit performance most efficiently and at the least cost, thereby resulting in the reduction of maintenance cost on contact actuating devices and their associated circuitry.
  • a feature of this invention is a single combinational contact which will properly make and break circuits regardless of whether or not they carry current or have a potential thereon.
  • a specific feature of this invention is a contact comprising an exposed layer of an alloy including by weight at least 50 percent gold and a negligible amount of metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium and an unexposed layer of an alloy thereunder including by weight at least 50 percent metal of said group or 50 percent silver or some combination thereof.
  • the base metals e. g., copper, nickel, etc.
  • the base metals are generally inexpensive as well as resistant to erosion and to other deleterious effects of arcing. Even so, the formation of oxide and/ or sulfide films on their surfaces with the resulting large increase in contact resistance has always made them a poor choice for general contact use, I such as in telephone systems. however, that these films are only likely to prove objectionable when the relative movement between contacts is small.
  • the platinum-group metals which I include platinum, palladium, iridium, rhodium, ruthenium and osmium, when used as contact material will continue to provide a low resistive .circuit path as they do not suffer from the formation of oxide or sulfide films on their surfaces.
  • the platinum group metals do have the disadvantage of being relatively expensive.
  • Gold electrically speaking, has been recognized in the prior art for many years as an excellent contact material. As is the case with the platinum-group metals, gold provides a dependable low resistive circuit path which is not affected by surface film formations. However, gold, as compared with the platinum group metals, is subject to excessive deterioration from mechanical wear as well as electrical erosion. Its use on contacts making or breaking appreciable amounts of current (say greater than 0.4 ,amperewhas been found generally unsatisfactory. The
  • Silver has also been used for many years as a contact material. It, too, provides a low resistive path but has as an inherent disadvantage a propensity to tarnish when exposed to the atmosphere. This increases the resistance of a circuit path and more importantly precludes silver contacts from being used satisfactorily in many talking circuits because of the so-called tarnish noise.
  • brown powder designates a circuit with no voltage differential between the contacts during closure and no current flowing between the contacts during opening, i. e., a circuit producing little or no arcing when opened or closed. Investigation of Wet circuit contacts of this group (those interposed in circuits which are on opening or closing) show little or no evidence of this brown powder formation.
  • this brown powder is an organic deposit of good insulating properties which forms on dry circuit platinum group metal contacts when operated in the presence of organic materials. Though it is not certain by what process this organic deposit forms, there is good evidence to show that it is the result of organic vapors in the atmosphere becoming adsorbed on the surface of the platinum group metal.
  • the friction between the mating contact surfaces (when the electromagnetic devices operate or release) combined with what appears to be a catalytic action of platinum group metals transforms the adsorbed vapors into the finely divided solid organic deposit.
  • the collection of quantities of this organic deposit on mating surfaces causes circuit opens and occasionally produces variable-resistance contacts which create undesirable noise in telephone circuits. This organic deposit causes circuit opens in a manner similar to those caused by the presence of dust on contact surfaces; thus, contact opens that for years have been attributed to dust may well have been due, in many cases, to the presence of an organic deposit.
  • Figs. 1 and 2 of the drawing illustrate two structural configurations which this improved combinational contact may take.
  • a predominantly gold alloy layer 1 covers a predominantly platinum group or silver metal base layer 2 which is attached to a relay spring 3.
  • Fig. 2 shows a predominantly gold alloy cap 4 covering a predominantly platinum group or silver metal base 5 which is, in turn, afiixed to a relay spring 6.
  • the gold alloy overlay layer or cap may be affixed to the platinum or silver base in any convenient manner, and similarly, the base may be attached to the relay spring in any desired fashion.
  • a number of predominantly gold alloys can be used satisfactorily as an overlay material. While fine or pure gold will work satisfactorily from the standpoint of not encouraging the formation of organic deposits, its mechanical wear properties are so poor that it has been found advantageous to alloy it with other metals.
  • a particular alloy including by weight 70 percent gold and percent silver has been found to work well. This alloy is disclosed in Patent 1,673,267 issued June 12, 1928 to R. A. Price, wherein it is shown as a mount wire .for a filament in an electric lamp.
  • Alloys comprising predominant percentages of gold with the remainder of the metal selected from a group consisting of silver, copper, nickel and other base metals are also satisfactory as overlay alloys provided the percentages of these elements alloyed with goldare kept low enough to prevent the formation of objectionable oxide or sulfide films on the surface of the gold alloy.
  • any predominantly gold alloy as described above has been found satisfactory as an overlay over a metal base including metal from the platinum group or silver.
  • a silver or silver alloy base is employed for contacts, however, the noise requirement of the circuit must be considered. Because long distances are spanned and intricate switching systems are employed by most American telephone installations, noise requirements are more stringent than those found in European installations. Fortunately, most talking circuits are dry circuits. Most of them close through the gold overlay and are little affected by the silver base. Wet circuits ordinarily are not talking circuits and silver-caused tarnish noise is not objectionable thereon. Quite often if the circuit requirements are not too high, the cost advantage of a silver base as compared to a platinum group metal base may outweigh the small increase in noise level which accompanies the use of a silver base.
  • the thickness of the 70 percent gold and 30 percent silver alloy overlay be at least .0005 of an inch thick.
  • the thickness of the gold alloy overlay should be between one and one and onehalf mils.
  • An electrical contact comprising an overlay cap of alloy including by weight at least 50 percent gold and not more than 5 percent metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium, and osmium, said cap covering an alloy including by weight at least 50 percent metal of said group.
  • An electrical contact comprising an exposed layer of an alloy including by weight 70 percent gold and 30 percent silver and a layer of palladium thereunder.
  • An electrical contact comprising an exposed layer of an alloy including by weight 70 percent gold and 30 percent silver and a layer of silver thereunder.
  • An electrical contact comprising an exposed layer of alloy between one and one and one-half mils thick including by weight 70 percent gold and 30 percent silver and a layer of palladium thereunder.
  • An electrical contact comprising an exposed layer of alloy at ,least one mil thick including by weight at least '50 percent gold and not more than 5 percent metal selected from the group consisting of platinum, palladium, iridium, rhodium, ruthenium, and osmium and a layer of alloy thereunder including by weight at least 50 percent metal of said group and the remainder nickel.
  • An electrical contact comprising an overlay cap of a metallic alloy at ;least one mil thick including by weight at least 50 percent gold and not more than 5 percent metal selected'from the group consisting of platinum,
  • said cap covering a metallic alloy including by weight at least 50 percent silver.
  • An electrical contact comprising an exposed layer of alloy including by weight 70 percent gold and 30 percent silver and a layer of alloy thereunder. including by weight at least 50 percent metal selected from a group consisting of platinum, palladium, iridium, rhodium, ruthenium, and osmium.
  • An electrical contact comprising an exposed layer of alloy including by weight 72 percent gold, 26.2 percent silver, and 1.8 percent nickel and a layer of alloy thereunder including by Weight at least 50 percent metal selected from a group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium.
  • a pair of cooperating electrical make-and-break contacts each of said contacts comprising an exposed layer of alloy including by weight at least 50 percent gold and not more than percent metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium, and osmium, and a layer of alloy thereunder including by weight at least 50 percent metal of said group, said exposed layers of said contacts cooperating with each other.
  • each contact comprising an alloy cap at least .0005 inch thick and including by weight 70 percent gold and 30 percent silver, said cap covering an alloy including by weight at least 50 percent palladium and the remainder nickel, said caps of said contacts cooperating with each other.
  • An electrical contact comprising an exposed layer of alloy including by weight at least 50 percent gold and a negligible amount of metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium and a layer of alloy thereunder including by weight at least 50 percent metal of said group.
  • An electrical contact comprising an exposed layer of alloy including by weight at least 50 percent gold and a negligible amount of metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium and a layer of alloy thereunder including by Weight at least 50 percent silver.
  • An electrical contact comprising an exposed layer of alloy including by weight 50 to 100 percent gold, 0 to 35 percent silver, and 0 to 6 percent metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium andosmium and a layer of alloy thereunder including by weight at least 50 percent metal of said group.
  • An electrical contact comprising, in combination, an exposed layer not less than .001 inch thick of an alloy including by weight 7 2 percent gold, 26.2 percent silver,
  • An electrical contact comprising an exposed layer of alloy including by weight 91.7 percent gold and 8.3 percent silver and a layer of alloy thereunder including by weight at least 50 percent metal selected from the group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium.
  • An electrical contact comprising an exposed layer of an alloy including by weight 91.7 percent gold and 8.3 percent silver and a layer of silver thereunder.
  • a pair of cooperating electrical make-and-break contacts each of said contacts comprising an exposed layer of alloy at least .0005 inch thick and including by weight at least 50 percent gold and a negligible amount of metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium and a layer of alloy thereunder including by weight at least 50 percent metal of said group, said exposed layers of said contacts cooperating with each other.
  • a pair of cooperating electrical make-and-break contacts each of said contacts comprising an exposed layer of alloy at least .0005 inch thick and including by weight at least 50 percent gold and a negligible amount of metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium and a layer of alloy thereunder including by weight at least 50 percent silver, said exposed layers of said contacts cooperating with each other.
  • a pair of cooperating electrical make-and-break contacts each of said contacts comprising an exposed layer of alloy at least .0005 inch thick and including by weight 50 to percent gold, 0 to 35 percent silver, and 0 to 6 percent metal from the group consisting of platinum, palladium, iridium, rhodium, ruthenium and osmium and a layer of alloy thereunder including by weight at least 50 percent metal of said group, said exposed layers of said contacts cooperating with each other.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Contacts (AREA)
US413633A 1954-03-02 1954-03-02 Electrical contact Expired - Lifetime US2812406A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE536121D BE536121A (es) 1954-03-02
NL92647D NL92647C (es) 1954-03-02
NL193594D NL193594A (es) 1954-03-02
US413633A US2812406A (en) 1954-03-02 1954-03-02 Electrical contact
FR1118924D FR1118924A (fr) 1954-03-02 1955-01-07 Perfectionnements aux contacts électriques
DEW15742A DE1078774B (de) 1954-03-02 1955-01-14 Elektrischer Kontakt
GB5701/55A GB765273A (en) 1954-03-02 1955-02-25 Electrical contacts

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US413633A US2812406A (en) 1954-03-02 1954-03-02 Electrical contact

Publications (1)

Publication Number Publication Date
US2812406A true US2812406A (en) 1957-11-05

Family

ID=23638008

Family Applications (1)

Application Number Title Priority Date Filing Date
US413633A Expired - Lifetime US2812406A (en) 1954-03-02 1954-03-02 Electrical contact

Country Status (6)

Country Link
US (1) US2812406A (es)
BE (1) BE536121A (es)
DE (1) DE1078774B (es)
FR (1) FR1118924A (es)
GB (1) GB765273A (es)
NL (2) NL193594A (es)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3002074A (en) * 1959-06-08 1961-09-26 Daystrom Inc Relay contact system
US3041118A (en) * 1960-07-25 1962-06-26 Gen Electric Electric contact element
US3086285A (en) * 1957-11-05 1963-04-23 Engelhard Ind Inc Electrical contacts
US3229357A (en) * 1961-07-05 1966-01-18 Schlatter Ag Process and apparatus for manufacturing contact blades
US3249728A (en) * 1962-08-01 1966-05-03 Nippon Electric Co Reed switch having multi-layer diffused contacts
US3251121A (en) * 1962-08-07 1966-05-17 Bell Telephone Labor Inc Method of making reed-type switch contacts
US3331040A (en) * 1963-05-13 1967-07-11 Int Standard Electric Corp Miniature diaphragm relay
DE1764233B1 (de) * 1968-04-27 1971-05-06 Heraeus Gmbh W C Elektrischer schwachstromkontakt
US3649795A (en) * 1969-05-01 1972-03-14 William Ralph Byrne Electrical contacts
JPS49100164U (es) * 1972-12-19 1974-08-29
US3885115A (en) * 1972-11-15 1975-05-20 Bunker Ramo Switch-over contact
JPS5569913A (en) * 1979-10-16 1980-05-27 Matsushita Electric Works Ltd Method of manufacturing contactor
US4641002A (en) * 1978-07-19 1987-02-03 Gesellschaft Fuer Kernenerg Ieverwertung In Schiffbau Und Schiffahat Gmbh Electrical contact
WO1996026526A1 (en) * 1995-02-24 1996-08-29 Mabuchi Motor Co., Ltd. Sliding contact material, clad composite material, commutator employing said material and direct current motor employing said commutator
US5598629A (en) * 1991-12-04 1997-02-04 Siemens Aktiengesellschaft Process for making contact with a silver contact base
US20040238338A1 (en) * 2001-08-03 2004-12-02 Joachim Ganz Electric contact
WO2007019390A2 (en) * 2005-08-03 2007-02-15 Ccmi Corporation Enhancement of surface-active solid-phase heterogeneous catalysts

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2604291C3 (de) * 1976-02-04 1981-08-20 Siemens AG, 1000 Berlin und 8000 München Werkstoffanordnung für elektrische Schwachstromkontakte
DE2940772C2 (de) * 1979-10-08 1982-09-09 W.C. Heraeus Gmbh, 6450 Hanau Elektrischer Schwachstromkontakt
EP0082647A3 (en) * 1981-12-10 1983-07-27 Johnson Matthey Public Limited Company Light duty corrosion resistant contacts
DE3345162C1 (de) * 1983-12-14 1984-11-15 Degussa Ag, 6000 Frankfurt Werkstoffe für Schwachstromkontakte
DE19809450A1 (de) * 1998-03-06 1999-09-23 Inovan Stroebe Elektrisches Mehrlagen-Kontaktprofil

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US937284A (en) * 1909-02-24 1909-10-19 Western Electric Co Alloy.
US1561247A (en) * 1923-09-07 1925-11-10 Western Electric Co Metallic composition
US2241262A (en) * 1939-10-26 1941-05-06 Baker & Co Inc Electrical contact
US2300286A (en) * 1941-05-08 1942-10-27 Fansteel Metallurgical Corp Electrical contact
US2600175A (en) * 1946-09-11 1952-06-10 Metals & Controls Corp Electrical contact
US2735907A (en) * 1956-02-21 Moisture

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH113777A (de) * 1924-08-14 1926-02-01 Bell Telephone Mfg Metallegierung für elektrische Kontakte usw.
DE727512C (de) * 1939-11-30 1942-11-05 Heraeus Gmbh W C Elektrischer Kontakt
DE762506C (de) * 1942-11-21 1954-04-29 Degussa Hochsalzsaeurebestaendige Apparateteile
DE858898C (de) * 1944-05-31 1952-12-11 Heraeus Gmbh W C Goldlegierung

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2735907A (en) * 1956-02-21 Moisture
US937284A (en) * 1909-02-24 1909-10-19 Western Electric Co Alloy.
US1561247A (en) * 1923-09-07 1925-11-10 Western Electric Co Metallic composition
US2241262A (en) * 1939-10-26 1941-05-06 Baker & Co Inc Electrical contact
US2300286A (en) * 1941-05-08 1942-10-27 Fansteel Metallurgical Corp Electrical contact
US2600175A (en) * 1946-09-11 1952-06-10 Metals & Controls Corp Electrical contact

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3086285A (en) * 1957-11-05 1963-04-23 Engelhard Ind Inc Electrical contacts
US3002074A (en) * 1959-06-08 1961-09-26 Daystrom Inc Relay contact system
US3041118A (en) * 1960-07-25 1962-06-26 Gen Electric Electric contact element
US3229357A (en) * 1961-07-05 1966-01-18 Schlatter Ag Process and apparatus for manufacturing contact blades
US3249728A (en) * 1962-08-01 1966-05-03 Nippon Electric Co Reed switch having multi-layer diffused contacts
US3251121A (en) * 1962-08-07 1966-05-17 Bell Telephone Labor Inc Method of making reed-type switch contacts
US3331040A (en) * 1963-05-13 1967-07-11 Int Standard Electric Corp Miniature diaphragm relay
DE1764233B1 (de) * 1968-04-27 1971-05-06 Heraeus Gmbh W C Elektrischer schwachstromkontakt
US3649795A (en) * 1969-05-01 1972-03-14 William Ralph Byrne Electrical contacts
US3885115A (en) * 1972-11-15 1975-05-20 Bunker Ramo Switch-over contact
JPS49100164U (es) * 1972-12-19 1974-08-29
JPS5331009Y2 (es) * 1972-12-19 1978-08-02
US4641002A (en) * 1978-07-19 1987-02-03 Gesellschaft Fuer Kernenerg Ieverwertung In Schiffbau Und Schiffahat Gmbh Electrical contact
JPS5569913A (en) * 1979-10-16 1980-05-27 Matsushita Electric Works Ltd Method of manufacturing contactor
US5598629A (en) * 1991-12-04 1997-02-04 Siemens Aktiengesellschaft Process for making contact with a silver contact base
US5799771A (en) * 1991-12-04 1998-09-01 Siemens Aktiengesellschaft Contact with a silver contact base and process for making the same
WO1996026526A1 (en) * 1995-02-24 1996-08-29 Mabuchi Motor Co., Ltd. Sliding contact material, clad composite material, commutator employing said material and direct current motor employing said commutator
US20040238338A1 (en) * 2001-08-03 2004-12-02 Joachim Ganz Electric contact
US7015406B2 (en) * 2001-08-03 2006-03-21 Ami Doduco Gmbh Electric contact
WO2007019390A2 (en) * 2005-08-03 2007-02-15 Ccmi Corporation Enhancement of surface-active solid-phase heterogeneous catalysts
WO2007019390A3 (en) * 2005-08-03 2007-03-29 Ccmi Corp Enhancement of surface-active solid-phase heterogeneous catalysts
US9339808B2 (en) 2005-08-03 2016-05-17 Ccmi Corporation Enhancement of surface-active solid-phase heterogeneous catalysts

Also Published As

Publication number Publication date
GB765273A (en) 1957-01-09
NL92647C (es)
DE1078774B (de) 1960-03-31
BE536121A (es)
FR1118924A (fr) 1956-06-13
NL193594A (es)

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