US3251121A - Method of making reed-type switch contacts - Google Patents

Method of making reed-type switch contacts Download PDF

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Publication number
US3251121A
US3251121A US215392A US21539262A US3251121A US 3251121 A US3251121 A US 3251121A US 215392 A US215392 A US 215392A US 21539262 A US21539262 A US 21539262A US 3251121 A US3251121 A US 3251121A
Authority
US
United States
Prior art keywords
reed
gold
layer
silver
switch
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
US215392A
Other languages
English (en)
Inventor
Katharine B Prival
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 NL126476D priority Critical patent/NL126476C/xx
Priority to BE635855D priority patent/BE635855A/xx
Priority to GB1054187D priority patent/GB1054187A/en
Priority to NL296271D priority patent/NL296271A/xx
Priority to US215392A priority patent/US3251121A/en
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to FR939847A priority patent/FR1361233A/fr
Priority to DE1521591A priority patent/DE1521591C3/de
Priority to JP3633563A priority patent/JPS409658B1/ja
Priority to SE8397/63A priority patent/SE310916B/xx
Application granted granted Critical
Publication of US3251121A publication Critical patent/US3251121A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/0201—Materials for reed contacts
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00—Electromagnetic relays
    • H01H51/30—Electromagnetic relays specially adapted for actuation by AC
    • H01H51/32—Frequency relays; Mechanically-tuned relays
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S65/00—Glass manufacturing
    • Y10S65/12—Reed switch
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49105—Switch making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49117—Conductor or circuit manufacturing
    • Y10T29/49204—Contact or terminal manufacturing
    • Y10T29/49208—Contact or terminal manufacturing by assembling plural parts
    • Y10T29/4921—Contact or terminal manufacturing by assembling plural parts with bonding
    • Y10T29/49211—Contact or terminal manufacturing by assembling plural parts with bonding of fused material
    • Y10T29/49213—Metal

Definitions

  • switching devices in typical telephone switching systems, by way of example, thirty or more switching devices in series may be required to effect the establishing of a circuit between two subscribers over which voice currents are to be transmitted. Obviously, a minimum and stable resistance and freedom from contact sticking must be realized by these switching devices. Variations in resistance of any device included in a circuit carrying voice currents, or other information bearing signals, are particularly objectionable since they may produce noise" and probably appreciable distortion. Also, if the contacts of a switching device stick, the device is, of course, no longer capable of functioning properly.
  • the reed-type switch was invented over two decades ago and represents a distinct advance in the art from the standpoints of simplicity, reliability and small size for an electromagnetically operated device.
  • This switch relatively minute, closely spaced reeds of magnetic material are encapsulated in a glass tube containing an inert gas under pressure.
  • the switch is operated by magnetic flux generated by a very small solenoidal coil surrounding the center of the tube.
  • This switching device has proven suitable for extensive use in switching systems of the above mentioned types.
  • a pair of fiat reeds of a magnetic material are enclosed in a cylindrical glass tube, the reeds being supported as cantilevers with their free ends overlapping longitudinally at the center of the glass tube but being separated by a small gap.
  • the supported ends of the reeds are sealed into glass seals at the opposite ends of the glass tube and extend beyond the glass seals to permit electrical connections to be made to the reeds.
  • a solenoidal coil placed centrally on the glass tube and surrounding the free ends of the reeds constitutes the operating means. Passage of current through the coil creates a flux which magnetizes the free ends of the reeds and draws them together.
  • the glass tube is usuallyfilled with a chemically inert gas at a pressure somewhat above atmospheric pressure prior to sealing.
  • At least three sizes of reed switch all relatively quite 3,251,121 Patented May 17, 1966 small, have been used in appreciable quantities.
  • a medium sized one is, for example, enclosed in a glass tube approximately one inch long and one-eighth inch in outer diameter, the movable portion of each reed within the glass tube weighing approximately 0.019 gram and being approximately 0.4 inch long, 0.05 inch wide and 8 mils thick.
  • a larger sized reed switch employs reeds having movable portions within the enclosing glass tube which weigh approximately 0.19 gram, the over-all di-' mensions of the parts of this size switch being approximately three times those of corresponding parts of the medium size.
  • a third smaller size reedsw tch is approximately one-half the size of the medium size and the active portions of the reeds are approximately onehalf the weight of the active portions of the reeds of the medium size switch.
  • Other sizes could, of course,
  • the spacing between the longitudinally overlapping portions 'of the reed switch within the glass tube is madevery small, for example, six mils for a medium size switch.
  • the contacting force developed by the field of the coil may be low, for example only a few grams, so that it is necessary to employ a minimum thickness of non-magnetic materials over the surfaces which are brought into contact with each other since these materials obviously increase the reluctance of the magnetic path and therefore reduce the contacting force.
  • An appreciably higher resistance in the contact area would, of
  • the gold-silver alloy when enclosed in an oxygen-free atmosphere, is found to have substantially ideal properties, that is, very low and stable resistance and no tendency to stick. It is further significant to note that gold-silver alloys are not completely satisfactory contact metals for use in the open air since tarnishing or corrosion may be sufficiently troublesome to limit their use to contacts in which an effective wiping action of the contacting surfaces on each other takes place and maintains the surfaces in a clean condition.
  • the reed switch does not provide any appreciable wiping action and, as noted above, has a relatively very small force holding the contacts together when in the operated position. It was therefore not expected that merely placing a layer of silver over the layer of gold and heating the assembly would provide a satisfactorysolution as a contact surface for reed switches.
  • the principal object of the invention is, accordingly, to significantly reduce the difficulties arising from high contact resistance and/ or sticking of the contacts in reed-type switches and relays.
  • FIG. 1 illustrates to an enlarged scale the reed assembly of a reed-type switch enclosed in its cylindrical glass tube;
  • FIG. 2 illustrates to a magnification of 1,000 times the types of alloy layers formed on the contact surfaces of the reeds of a reed switch by the processes of the invention.
  • a medium size reed switch is shown to an enlarged scale and comprises a pair of reeds 16 and 18 which are of magnetic material, each held atone end only by members 24 and 26, respectively.
  • Members 24 and 26 need not be of magnetic material but should have the same temperature coefiicient of expansion as glass since they in turn are held by seals 12 and 14, respectively, at the ends of the enclosing cylindrical glass tube 10, as shown.
  • the reed and its support may be made in one piece.
  • the free ends of reeds 16 and 18 are adjacent but spaced apart by a small distance, as for example, substantially six mils for the medium sized switch. They overlap longitudinally by a short distance as for example by substantially 30 mils for the medium sized switch.
  • Reeds 16 and 18 may be of any suitable magnetic material.
  • a nickel-iron alloy containing 51 percent nickel is magnetically satisfactory and has the additional advantage that it has substantially the same temperature coefficient of expansion as readily available types of glass and hence can be sealed into the ends of the glass tube.
  • Other magnetic materials may require a twopiece construction, namely, a lead-out portion of a metal having a suitable coefficient of expansion welded to a reed portion having the appropriate magnetic properties.
  • Conductive members 24 and 26 extend through the end seals 12 and 14 to provide convenient, accessible, electrical connecting means to their respective associated reeds. Typical dimensions for the reeds and tube are mentioned hereinabove. As previously mentioned, the glass tube is usually filled with a chemically inert gas at a pressure somewhat above atmospheric pressure.
  • a preferred process of the invention for applying coatings 20 and 22 on the free ends of reeds 16 and 18, respectively comprises cleaning the surface thoroughly as, for example, by vapor phase degreasing followed by a hot acid dip using a 50 percent hydrochloric acid solution in accordance with conventional practice in the art, electrolytically depositing a layer of gold of from seven to fourteen milligrams per square inch over the end portion to be covered, electrolytically depositing a layer of silver of from one and one-half to two and one-half milligrams per square inch over the layer of gold, and diffusing the applied layers into each other and into the surface of the reed by heating to a temperature of from 800 to 950 degrees centigrade for a period of from ten to sixty minutes.
  • the weight of silver deposited should be between one-quarter and one-sixth of the weight of the gold deposited.
  • the large size switch mentioned above, should have noble metal layers near the maximum values mentioned above, median size switches should have median thickness layers and the small size switch near the minimum thicknesses mentioned above.
  • Photomicrographs were taken of cross-sectional portions of a nickeliron reed (51 percent nickel) for a medium sized switch, the reed having been coated and diffused in accordance with the process described above.
  • a very thin layer 5t ⁇ believed to be essentially of a gold-silver alloy having a thickness of substantially one micron is formed on the outer surface.
  • An appreciably thicker, irregular layer 52 believed to be of a varying composition alloy of gold, silver, nickel and iron, the proportions of nickel and iron decreasing appreciably with distance from the center of the reed, layer 52 having a thickness varying between two-tenths to six-tenths of a mil, is formed between the body of the reed and the first mentioned very thin layer 50.
  • the surface represented in FIG. 2 was etched with acid to clean it.
  • Lines 54 represent crystal boundaries of the nickel-iron reed.
  • the combined thickness of the alloy layers 50 and 52 should be between onetenth and one-thirtieth of the thickness of the magnetic reed.
  • the outstandingly satisfactory operation of reed switches of the invention is attributable to the formation of the very thin gold-silver alloy layer 50, having substantially no base metals therein, as described above, if the additional intermediate heat treatment with the gold layer only on the reed is employed, the layer of silver should be applied and heat treated before the lapse of any long time interval to avoid the possibility that the base metals, usually nickel or iron, or both, should diffuse to the outer surface of the gold and subsequently into the gold-silver alloy.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Contacts (AREA)
  • Manufacture Of Switches (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
US215392A 1962-08-07 1962-08-07 Method of making reed-type switch contacts Expired - Lifetime US3251121A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
GB1054187D GB1054187A (en)van) 1962-08-07
NL296271D NL296271A (en)van) 1962-08-07
NL126476D NL126476C (en)van) 1962-08-07
BE635855D BE635855A (en)van) 1962-08-07
US215392A US3251121A (en) 1962-08-07 1962-08-07 Method of making reed-type switch contacts
FR939847A FR1361233A (fr) 1962-08-07 1963-06-28 Contacts de commutateurs du type à lames vibrantes
DE1521591A DE1521591C3 (de) 1962-08-07 1963-07-17 Verfahren zur Bildung einer Kontaktfläche auf einer Schalterzunge
JP3633563A JPS409658B1 (en)van) 1962-08-07 1963-07-17
SE8397/63A SE310916B (en)van) 1962-08-07 1963-07-30

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US215392A US3251121A (en) 1962-08-07 1962-08-07 Method of making reed-type switch contacts

Publications (1)

Publication Number Publication Date
US3251121A true US3251121A (en) 1966-05-17

Family

ID=22802811

Family Applications (1)

Application Number Title Priority Date Filing Date
US215392A Expired - Lifetime US3251121A (en) 1962-08-07 1962-08-07 Method of making reed-type switch contacts

Country Status (8)

Country Link
US (1) US3251121A (en)van)
JP (1) JPS409658B1 (en)van)
BE (1) BE635855A (en)van)
DE (1) DE1521591C3 (en)van)
FR (1) FR1361233A (en)van)
GB (1) GB1054187A (en)van)
NL (2) NL296271A (en)van)
SE (1) SE310916B (en)van)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443312A (en) * 1962-06-04 1969-05-13 Hitachi Ltd Method of making gas-filled enclosed switchgear with copper contacts
US3495061A (en) * 1968-07-11 1970-02-10 Ibm Contacts for reed switches
US3579822A (en) * 1968-05-13 1971-05-25 Frank L Dieterich Method and blank for making potentiometer contact springs
US3668355A (en) * 1971-01-27 1972-06-06 Northern Electric Co Reed material for sealed contact application
US3689722A (en) * 1971-09-23 1972-09-05 Bell Telephone Labor Inc Reed switch having contacts plated with a thin silver layer
US3719567A (en) * 1970-12-31 1973-03-06 Nippon Telegraph & Telephone Method for producing a contact reed
US3755892A (en) * 1968-05-13 1973-09-04 F Dieterich Potentiometer contact springs
US3805378A (en) * 1972-02-22 1974-04-23 Bell Telephone Labor Inc Manufacture of remanent reed switch
US3961148A (en) * 1973-10-23 1976-06-01 Siemens Aktiengesellschaft Dry-reed contact construction
US4309461A (en) * 1980-05-15 1982-01-05 Chugai-Duki Kogyo Kabushiki-Kaisha Method of compounding decorative precious metal alloy selectively onto austenite stainless steel article
US4432487A (en) * 1982-01-18 1984-02-21 Chugai Denki Kogyo Kabushiki Kaisha Method of overlaying stainless steel material for decorative articles and ornaments with a precious metal alloy
US4475991A (en) * 1983-03-25 1984-10-09 Chugai Denki Kogyo K.K. Method of diffusion cladding a Fe-containing base material for decorative articles and ornaments with precious metal constituents including Ag
WO2002025702A3 (en) * 2000-09-20 2002-08-01 Stephen M Kim Semiconductor product with a silver and gold alloy
US20030006787A1 (en) * 2000-06-28 2003-01-09 Toshio Kazama Conductive contact
US20080258852A1 (en) * 2007-04-18 2008-10-23 Key Safety Systems, Inc. Reed switch contact coating
US11309140B2 (en) * 2019-01-04 2022-04-19 Littelfuse, Inc. Contact switch coating

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1906689A (en) * 1929-03-30 1933-05-02 American Platinum Works Nib for gold pen-points
US2812406A (en) * 1954-03-02 1957-11-05 Bell Telephone Labor Inc Electrical contact
US2932880A (en) * 1955-02-24 1960-04-19 Western Electric Co Method of making electrical switching devices
US2937434A (en) * 1956-06-14 1960-05-24 Gen Controls Co Process of manufacturing switch contacts
US3125654A (en) * 1961-10-31 1964-03-17 Electrical contacting surfaces

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1906689A (en) * 1929-03-30 1933-05-02 American Platinum Works Nib for gold pen-points
US2812406A (en) * 1954-03-02 1957-11-05 Bell Telephone Labor Inc Electrical contact
US2932880A (en) * 1955-02-24 1960-04-19 Western Electric Co Method of making electrical switching devices
US2937434A (en) * 1956-06-14 1960-05-24 Gen Controls Co Process of manufacturing switch contacts
US3125654A (en) * 1961-10-31 1964-03-17 Electrical contacting surfaces

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443312A (en) * 1962-06-04 1969-05-13 Hitachi Ltd Method of making gas-filled enclosed switchgear with copper contacts
US3579822A (en) * 1968-05-13 1971-05-25 Frank L Dieterich Method and blank for making potentiometer contact springs
US3755892A (en) * 1968-05-13 1973-09-04 F Dieterich Potentiometer contact springs
US3495061A (en) * 1968-07-11 1970-02-10 Ibm Contacts for reed switches
US3719567A (en) * 1970-12-31 1973-03-06 Nippon Telegraph & Telephone Method for producing a contact reed
US3668355A (en) * 1971-01-27 1972-06-06 Northern Electric Co Reed material for sealed contact application
US3689722A (en) * 1971-09-23 1972-09-05 Bell Telephone Labor Inc Reed switch having contacts plated with a thin silver layer
US3805378A (en) * 1972-02-22 1974-04-23 Bell Telephone Labor Inc Manufacture of remanent reed switch
US3961148A (en) * 1973-10-23 1976-06-01 Siemens Aktiengesellschaft Dry-reed contact construction
US4309461A (en) * 1980-05-15 1982-01-05 Chugai-Duki Kogyo Kabushiki-Kaisha Method of compounding decorative precious metal alloy selectively onto austenite stainless steel article
US4432487A (en) * 1982-01-18 1984-02-21 Chugai Denki Kogyo Kabushiki Kaisha Method of overlaying stainless steel material for decorative articles and ornaments with a precious metal alloy
US4475991A (en) * 1983-03-25 1984-10-09 Chugai Denki Kogyo K.K. Method of diffusion cladding a Fe-containing base material for decorative articles and ornaments with precious metal constituents including Ag
US20030006787A1 (en) * 2000-06-28 2003-01-09 Toshio Kazama Conductive contact
WO2002025702A3 (en) * 2000-09-20 2002-08-01 Stephen M Kim Semiconductor product with a silver and gold alloy
US20080258852A1 (en) * 2007-04-18 2008-10-23 Key Safety Systems, Inc. Reed switch contact coating
US7564330B2 (en) 2007-04-18 2009-07-21 Key Safety Systems, Inc. Reed switch contact coating
US11309140B2 (en) * 2019-01-04 2022-04-19 Littelfuse, Inc. Contact switch coating
US20220122784A1 (en) * 2019-01-04 2022-04-21 Littelfuse, Inc. Contact switch coating

Also Published As

Publication number Publication date
DE1521591C3 (de) 1975-08-28
DE1521591A1 (de) 1969-09-18
FR1361233A (fr) 1964-05-15
SE310916B (en)van) 1969-05-19
NL296271A (en)van)
NL126476C (en)van)
JPS409658B1 (en)van) 1965-05-18
BE635855A (en)van)
GB1054187A (en)van)
DE1521591B2 (de) 1971-12-16

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