US3329914A - Sealed magnetic contact device - Google Patents

Sealed magnetic contact device Download PDF

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Publication number
US3329914A
US3329914A US530212A US53021266A US3329914A US 3329914 A US3329914 A US 3329914A US 530212 A US530212 A US 530212A US 53021266 A US53021266 A US 53021266A US 3329914 A US3329914 A US 3329914A
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US
United States
Prior art keywords
bars
armature
contact
vessel
sealed
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
US530212A
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English (en)
Inventor
Woodhead Harry Stanley
Sloley Herbert John
Waugh William Kelly
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.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
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
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Application granted granted Critical
Publication of US3329914A publication Critical patent/US3329914A/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
    • 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

  • the invention relates to a sealed magnetic contact device for use, in cooperation with an electromagnet not part of the device, as a relay, and commonly known as a reed switch.
  • One form of reed switch with which the invention is particularly concerned consists of a small glass bulb, which may typically be some mm. in diameter and about 20 mm. long, into one end of which are sealed a pair of bars of magnetisable material one of which carries a fixed contact and the other a movable contact on a spring-loaded armature.
  • a magnetic field operates the armature against its spring-loading.
  • both the bars are of magnetisable material is to facilitate sealing into the glass; the two bars are initially the legs of a hairpin-shaped piece of Wire of one of the well known glass-sealing ferromagnetic alloys, the loop of the hairpin being subsequently removed.
  • a difiiculty with this form of reed switch is that a longitudinally applied magnetising force establishes useless leakage fiux along the armature support limb. This acts as a magnetic shunt to the contact gap. It is desirable to reduce to a minimum magnetic leakage paths shunting the air gap between the armature and the fixed contact bar, while also reducing the direct air gaps to a minimum. Problems are also encountered in connection with bounce between the contacts, which calls for careful consideration of the spring and armature design.
  • a sealed magnetic contact device having two stationary, generally parallel, bars of magnetisable metal sealed through one end of a vessel, a fixed contact provided adjacent the end of one of the bars within the vessel, and an armature carrying a contact for cooperation with the fixed contact mounted by spring means from spacing means of magnetisable metal secured by an interposing member of non-magnetic material to the other one of tlie bars, the last mentioned bar terminating within the vessel short of the vicinity of the contacts.
  • FIG. 1 is a view of a complete device of the invention
  • FIG. 2 is a longitudinal section through the contact end of the device of FIG. 1 on a greatly enlarged scale
  • FIG. 3 is an end view of the device looking in the direction of the arrows in FIG. 2.
  • Two bars, 1 and 2 of ferromagnetic alloy sealing readily to glass, are sealed into one end of an elongated glass vessel 3, closed at its other end.
  • the bar 1 has an area adjacent its end plated with palladium to form a fixed contact 4.
  • the other bar 2 is terminated short of the vicinity of the contact 4, but has butt-joined to it an extension piece 5 of non-magnetic copper-nickel alloy.
  • This extension piece forms an interposing member be- 3,329,914 Patented July 4, 1967 tween the bar 2 and a spacing means 6 of magnetisa-ble material in the form of a long spacer 7 of ferromagnetic material and a short spacer 8, of the same material, superposed on one end to form a step.
  • a double leaf spring 9 of an alloy marketed under the trade name Vimetal is welded at one end on top of the spacer 8 and carries, welded to the same side and slightly spaced from the spacer 8, an armature 10.
  • the armature overlays the spacer 7 and is spaced from it the minimum distance allowable for movement of the armature and extends underneath the fixed contact, as viewed in the drawing.
  • Opposite the fixed contact the armature is plated with similar contact metal to that providing the fixed contact.
  • the contact end of the assembly is supported within the vessel 3 by means of a snubber 12.
  • the bars 1 and 2 were made from 0.047 inch diameter wire, the fixed contact member being 0.55 inch long within the envelope 3 and having an end portion 11 of reduced thickness 0.020 inch thick.
  • the bar 2 terminated at the commencement of this reduced portion.
  • the armature 10 was a strip of ferromagnetic alloy 0.204 inch long, 0.090 inch wide and 0.012 inch thick, while each of the leaves of the spring 9 were 0.225 inch long, 0.087 inch wide and 0.002 inch thick, with the effective length of the spring, between welds, 0.210 inch.
  • the gap between spacer 8 and armature 10 was 0.015 inch and that between the armature and spacer 7 was 0.008 inch.
  • a total magnetic pull of at least 12 grams or more was obtained, while a pull-off force of 6 grams minimum was provided by the spring.
  • the spring arrangement coupled with a light armature of sufiicient cross-section to avoid magnetic saturation, resulted in operate times, including bounce, of less than 1.5 milliseconds.
  • a sealed magnetic contact device having two stationary, generally parallel, bars of magnetizable metal sealed through one end only of a vessel which is closed at its other end, a fixed contact provided adjacent the end of one of the bars within the vessel, an armature carrying a movable contact for cooperation with the fixed contact, a spring fastened by one end to said armature, and spacing meansof magnetizable metal secured betwen said springand an inter-posing member of non-magnetic material, said member of non-magnetic material secured between the spacing means .and the other one of the bars, the last mentioned bar terminating within the vessel short of the vicinity of the contacts.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Contacts (AREA)
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US530212A 1965-02-26 1966-02-25 Sealed magnetic contact device Expired - Lifetime US3329914A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB835565 1965-02-26

Publications (1)

Publication Number Publication Date
US3329914A true US3329914A (en) 1967-07-04

Family

ID=9850941

Family Applications (1)

Application Number Title Priority Date Filing Date
US530212A Expired - Lifetime US3329914A (en) 1965-02-26 1966-02-25 Sealed magnetic contact device

Country Status (6)

Country Link
US (1) US3329914A (enrdf_load_stackoverflow)
BE (1) BE676834A (enrdf_load_stackoverflow)
CH (1) CH445600A (enrdf_load_stackoverflow)
DE (1) DE1974116U (enrdf_load_stackoverflow)
GB (1) GB1052545A (enrdf_load_stackoverflow)
NL (1) NL6602229A (enrdf_load_stackoverflow)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2648167A (en) * 1948-12-18 1953-08-11 Bell Telephone Labor Inc Machine for manufacturing switches
US2969434A (en) * 1958-01-30 1961-01-24 Bell Telephone Labor Inc Switching device
US3170053A (en) * 1958-12-06 1965-02-16 Int Standard Electric Corp Reed contact arranged within a protective envelope
US3236965A (en) * 1962-08-30 1966-02-22 Int Standard Electric Corp Sealed switch for strong currents

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2648167A (en) * 1948-12-18 1953-08-11 Bell Telephone Labor Inc Machine for manufacturing switches
US2969434A (en) * 1958-01-30 1961-01-24 Bell Telephone Labor Inc Switching device
US3170053A (en) * 1958-12-06 1965-02-16 Int Standard Electric Corp Reed contact arranged within a protective envelope
US3236965A (en) * 1962-08-30 1966-02-22 Int Standard Electric Corp Sealed switch for strong currents
US3238325A (en) * 1962-08-30 1966-03-01 Int Standard Electric Corp Magnetically operated sealed switch unit

Also Published As

Publication number Publication date
NL6602229A (enrdf_load_stackoverflow) 1966-08-29
DE1974116U (de) 1967-12-07
CH445600A (de) 1967-10-31
GB1052545A (enrdf_load_stackoverflow)
BE676834A (enrdf_load_stackoverflow) 1966-08-22

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