US3723688A - Switch spring for a relay - Google Patents

Switch spring for a relay Download PDF

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Publication number
US3723688A
US3723688A US00171521A US3723688DA US3723688A US 3723688 A US3723688 A US 3723688A US 00171521 A US00171521 A US 00171521A US 3723688D A US3723688D A US 3723688DA US 3723688 A US3723688 A US 3723688A
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US
United States
Prior art keywords
switch
core
contact
relay
switch spring
Prior art date
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Expired - Lifetime
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US00171521A
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English (en)
Inventor
I Eichhorst
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.)
Licentia Patent Verwaltungs GmbH
Original Assignee
Licentia Patent Verwaltungs GmbH
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.)
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Publication date
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Publication of US3723688A publication Critical patent/US3723688A/en
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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00—Electromagnetic relays
    • H01H51/28—Relays having both armature and contacts within a sealed casing outside which the operating coil is located, e.g. contact carried by a magnetic leaf spring or reed
    • H01H51/287—Details of the shape of the contact springs

Definitions

  • ABSTRACT A relay switch spring composed of an elongated flat strip which has a core made of an electrically conductive material surrounded by a sheath of material of a lower conductivity than the core material.
  • the strip has a free end to which a contact is connected so that the contact engages both the core and sheath material.
  • the present invention relates to a switch element, and more particularly to a switch spring for a relay such as a reed type relay.
  • a simple reed relay generally consists of two such switch springs which are made of a nickel-iron material usually in the ratio of 50:50. These springs are fused in a gastight manner in a glass tube. This ratio is chosen because of the glass fusing technique employed and for reasons associated with the magnetic phenomena involved.
  • switch springs When these switch springs are subjected to a longitudinally directed magnetic flux, they attract one another and thus establish an electrical contact. This contact point is generally coated with a special contact material, e.g., gold or rhodium.
  • the switch springs are made of a nickel-iron material of the aforementioned ratio, a comparatively high resistivity, that is in comparison with the abovementioned contact material, will be encountered. As a result it is generally the case that the resistance of reed contacts is much higher than the pure contact resistance, that is, at the point of contact.
  • a switch spring for a relay such as a reed type relay, consisting of a continuous core of electrically conductive material, e.g., copper, silver, gold or platinum, and an equally continuous sheath of ferromagnetic material which surrounds the core and which is electrically less conductive than the core material.
  • the spring is configured as an elongated strip having a free end which has a contact connected thereto. The contact engages both the core and sheath of the spring to establish therewith a conductive connection.
  • Such a switch spring can be easily fused in glass.
  • the thickness of the electrically conductive core may be approximately one third of the thickness of the spring.
  • thermoelectric junctions are reduced by two and that the remaining thermoelectric" junctions are spatially closer together, that is, they are disposed only in the vicinity of the actual contact point. This solves the need for switching without thermal stresses which would adversely affect the switching operation.
  • FIG. 1 is a longitudinal sectional view of a reed relay employing switch springs according to the present invention.
  • FIG. 2 is an enlarged partial side view of the switch springs of FIG. 1 showing the contact ends thereof.
  • FIG. 3 is a cross-sectional view of one embodiment of the switch spring of the'present invention made from a wire with a center core.
  • FIG. 4 is a cross-sectional view of a preferred form of a switch spring according to the present invention.
  • thermoelectric voltages problem A solution is provided by the present invention to the high thermoelectric voltages problem by the provision of a novel configuration of the switch spring contact, to be described hereinafter.
  • FIG. 1 shows a glass vial or tube 1 and the two switch springs 2 and 3 which were fused into the frontal faces 8 and 9 respectively of the glass vial 1.
  • the switch springs 2 and 3 consist of an electrically highly conductive core 4 which may consist of copper, silver, gold or platinum, and an outer sheath 5 of a ferromagnetic material. In order to achieve proper bonding this is generally a nickel-iron alloy having a mixing ratio of 50:50.
  • the switch springs 2 and 3 will be configured to have the flat shape shown in FIG. 4, although it should be understood that other and different shapes may be utilized as desired without departing from the scope of the invention.
  • a flat shaped spring as shown in FIG. 4 can be made for example of a cored wire having a cross-section as shown in FIG. 3 by flat pressing this cylindircal wire.
  • the switch springs 2 and 3 are shown to include contacts 6 of highly conductive material at their free ends.
  • the contacts 6 are connected to the free end of the spring switches 2 and 3 so that they engage and securely contact, both the sheaths S and the cores 4.
  • contact is made directly during switching, between the electrically highly conductive parts 4 and 6 of the two switch springs.
  • the resulting conductive path is indicated by the arrows 10.
  • the present invention achieves the desired objective of reducing the total switch contact resistance. For example, it has been found that the total switch contact resistance is reduced from a normal range of 50 to 60 m0 I toarange oflOto l5m.Qv
  • the contacts are configured to permit a direct connection between the cores of the two switch springs, the unsatisfactory thermoelectric junction" problem is substantially eliminated. That is, referring to FIG. 2, the current flow as indicated by arrows 10 will effectively by-pass two junctions, namely, the copperiron-nickel junctions.
  • a switch spring for a relay composed of an elongated strip having a free end and comprising a continuous core of an electrically highly conductive material, a continuous sheath surrounding and coextensive with said core and made of a ferromagnetic material, and, at the free end of said strip, a contact which engages both said core and said sheath and thus is conductively connected therewith.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Contacts (AREA)
  • Fuses (AREA)
US00171521A 1970-08-20 1971-08-13 Switch spring for a relay Expired - Lifetime US3723688A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19702041318 DE2041318B2 (de) 1970-08-20 1970-08-20 Schaltfeder für ein Schutzrohrkontakt-Relais

Publications (1)

Publication Number Publication Date
US3723688A true US3723688A (en) 1973-03-27

Family

ID=5780233

Family Applications (1)

Application Number Title Priority Date Filing Date
US00171521A Expired - Lifetime US3723688A (en) 1970-08-20 1971-08-13 Switch spring for a relay

Country Status (4)

Country Link
US (1) US3723688A (enExample)
DE (1) DE2041318B2 (enExample)
FR (1) FR2104559A5 (enExample)
GB (1) GB1340547A (enExample)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2204449A (en) * 1986-08-23 1988-11-09 Stc Plc Reed relay contacts

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2434992A (en) * 1943-09-27 1948-01-27 Metals & Controls Corp Electrical contact
US2921163A (en) * 1957-08-13 1960-01-12 Siemens Ag Tube-protected contact-making device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2434992A (en) * 1943-09-27 1948-01-27 Metals & Controls Corp Electrical contact
US2921163A (en) * 1957-08-13 1960-01-12 Siemens Ag Tube-protected contact-making device

Also Published As

Publication number Publication date
DE2041318B2 (de) 1972-07-20
FR2104559A5 (enExample) 1972-04-14
GB1340547A (en) 1973-12-12
DE2041318A1 (de) 1972-03-16

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