US2302546A - Electric switch - Google Patents

Electric switch Download PDF

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Publication number
US2302546A
US2302546A US340652A US34065240A US2302546A US 2302546 A US2302546 A US 2302546A US 340652 A US340652 A US 340652A US 34065240 A US34065240 A US 34065240A US 2302546 A US2302546 A US 2302546A
Authority
US
United States
Prior art keywords
contact
armature
mercury
pool
relay
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
US340652A
Other languages
English (en)
Inventor
Henry C Harrison
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 NL132811D priority Critical patent/NL132811B/xx
Priority to NL66974D priority patent/NL66974C/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US340652A priority patent/US2302546A/en
Priority to DEW907D priority patent/DE895183C/de
Application granted granted Critical
Publication of US2302546A publication Critical patent/US2302546A/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
    • H01H1/06—Contacts characterised by the shape or structure of the contact-making surface, e.g. grooved
    • H01H1/08—Contacts characterised by the shape or structure of the contact-making surface, e.g. grooved wetted with mercury
    • 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

  • This invention relates to electric switches and relays and particularly to those in which a conducting liquid, such as mercury, is used as the contact-making element.
  • the objects of the invention are to increase the efficiency and reliability of switches using liquid contacts; to increase the speed of operation; to simplify the construction; and in other respects to improve these devices.
  • mercury has certain distinct advantages over solid elements as a contact-making medium for electrical circuits. For instance a body of mercury presents a fresh surface for each successive contact closure and is not subject to the pitting and corroding effects that gradually reduce the usefulness of solid contact elements. With these advantages in view numerous varieties of mercury switches have been devised in the past. These generally fall in one or the other of two classes. In one of these the container is tilted or otherwise moved to cause the body of mercury within to shift its position, thus opening or closing the desired connections. In the other class an armature or other movable element is forced into a mercury pool, the free surface of the mercury being displaced into engagement with circuit-making contacts.
  • a spring may be provided to withdraw the armature when the operating force is removed, or the force of flotation of the mercury may be used to restore the armature.
  • a spring may be provided to withdraw the armature when the operating force is removed, or the force of flotation of the mercury may be used to restore the armature.
  • the disadvantages of these prior devices are overcome, while all the advantages of a liquid contact medium are retained, by means of a switch in which the movable switching element is of solid material, such as iron, in which all of the operating force is available for moving the switching element, and in which a supply oi' mercury adheres readily.
  • the envelope 0r container also includes one or more stationary solid contacts of like material which the movable contact engages and disengages in response to the movement of the armature in the magnetic field set up by a coil disposed on the exterior of the envelope.
  • the envelope contains a small pool or reservoir of mercury for maintaining a film or coating of mercury over the engaging surfaces of the moving and stationary contacts.
  • Figs. l and 2 are side views, partly in section, of a switch or relay incorporating the features of the invention. These figures illustrate the relay in its normal position;
  • Fig. 3 is a view similar to Fig. 1 showing the relay in its operated position
  • Fig. 4 is a cross-sectional view taken along the line 4-5 in Fig. 2;
  • Fig. 5 is an enlarged perspective view of the armature and movable contact
  • Fig. 6 is a perspective view of the relay including the magnetic structure and operating unit.
  • Figs. 'l to ll, inclusive are similar views of an alternative form of the relay in which circuits are controlled both in the normal and operating cury is always maintained at the points of con ducting material, preferably one to which merpositions.
  • Figs. 7 and 8 are side views, partly in section, showing the normal position of relay
  • Fig. 9 is a side view in section showing the relay in its operated position
  • Fig. l0 is an enlarged perspective view of the armature and the operating contact.
  • Fig. 1l is a cross-sectional view taken along lines ll--ll of Fig. 7;
  • Figs. 12 to 17, inclusive illustrate a third form of the relay.
  • Figs. l2 and 13 are side views, partly in section, illustrating the relay in its normal position
  • Fig. 14 is a similar view showing the relay in its operated position
  • Fig. 15 is an enlarged plan View showing the armature and movable contact
  • Fig. i6 is a perspective view of the armature and movable contact.
  • Fig. 17 is a perspective view of the relay assembly including the magnetic structure and the operating unit.
  • the relay here illustrated comprises an operating unit including a housing vessel or container in the form of a glass tube I and an electromagnetic armature 2.
  • the armature 2 com prises a strip of relatively thin magnetic metal cylindrically shaped to conform to the interior surface of the tube i.
  • the armature 2 is welded or otherwise secured at its upper end to a terminal post 3, which is sealed into the upper end of the glass tube i.
  • the lower end of the armature 2 carries the movable contact 4, which is integrally formed with the armature and is shaped in any suitable manner to present a contact-making surface for engagement with the stationary contact.
  • the upper end of the armature 2 has a series of transverse cuts I1, forming a spring portion which enables a fiexing movement of the armature when subjected to the magnetic eld and which also restores the armature to its normal position.
  • the terminal 5 projects through the bottom of the tube I and extends for a considerable distance above the bottom surface of the tube chamber.
  • the portion 'i' of the terminal 6 within the tube chamber is flattened somewhat, as shown in Fig. 2, to increase the area thereof, and the uppermost section of this attened portion constitutes the stationary contact-making surface 8 which is engaged and disengaged by the contactmaking surface 5 of the movable contact 4.
  • a pool of mercury 9 rests in the bottom of the tube i and surrounds the stationary contact 'I.
  • This pool is relatively shallow when compared with the projecting contact l.
  • the upper surface of the pool therefore, lies substantially below the end of the movable contact 4, so that the movable contact is not immersed in the pool and is not interfered with thereby in its movement into and out of engagement with the contacting surface of the stationary contact.
  • the attened contact "I, projecting up through the mercury pooly serves as a transfer agency whereby the forces of capillary attraction cause some of the mercury to creep up out of the pool and cover the entire surface of the contact 'I with a thin lrn of the liquid.
  • This coating or film of mercury which is illustrated particularly in Figs.
  • the magnetic operating structure of the relay which is illustrated in Fig. 6, comprises a coil I0 Wound on a core which is not visible in the drawings.
  • Magnetic pole members II and I2 are secured to the core in any suitable manner, and t-he other ends of these members are turned at right angles to form the pole-pieces I3 and I4.
  • These parts are held in position by a non-magnetic member I5, which extends beyond the polepieces I3 and I4 and serves as a receptacle for the housing tube I.
  • the protuberance I6 on the tube I engages the surface of the member I5 and locates the armature 2 in line with the air-gap formed by the pole-pieces I3 and I4.
  • each circuit closure is made by the merging of two liquid surfaces without the necessity of utilizing any appreciable amount of the operating force of the relay for moving the mercury.
  • the liquid surfaces maintain a good electrical contact and prevent any momentary openings in the event the solid contact members are subjected to vibration.
  • each circuit opening is effected by the disengagement of one mercury-coated surface from another.
  • the relay shown in Figs. 7 to 11 is similar to the one above described in that it utilizes the capillary attraction principle for maintaining a coating of mercury on the contact-making surfaces.
  • 'I'he sealed glass tube I8 is provided with an armature I 9, which is welded or otherwise secured to the terminal post 20.
  • the armature I9 is provided with transverse cuts 2l forming a spring portion at the upper end thereof.
  • the lower end 0f the armature is formed with a narrow integral contact strip 23 which is doubled and shaped as seen in Fig, 10 to present a depending portion and a Contact portion having two contact-making surfaces 24 and 25.
  • the depending portion of the movable terminal 23 is constantly immersed in a pool of mercury 28 and serves to attract the mercury by capillarity up out of the pool to the contact-making surfaces 24 and 25.
  • the mercury, which spreads itself in a lm over the entire surfaces 24 and 25, is transferred by physical engagement to the contactmaking surfaces on the lower ends of the stationary contacts 26 and 21.
  • the magnetic structure for the relay of Figs. 'I to 10 may also be the same as the one shown in Fig. 6.
  • the armature I9 assumes its normal position, and a closed path for the flow of current through the relay may be traced from the feed terminal 29, mercury pool 28, movable contact 23 and stationary contact 26.
  • the operating coil l0 is energized, the armature I9 is attracted from its normal position (Fig. 7) to its operated position (Fig. 9), and the circuit path through the relay is now transferred from the stationary contact 26 to the stationary contact 21.
  • the relay shown in Figs. 12 to 17, inclusive includes ,a housing container 30, formed by welding together two eyelets of any suitable nonmagnetic metal; or if desirable some material such as stainless steel may be used for the upper eyelet.
  • v The open end ofthe upper eyelet is sealed with a mass 3
  • the armature 32 is provided with pivot points 33 and 34, which engage the notches 35 and 36 formed at the junction of the upper and lower eyelet members comprising the container 30.
  • a contact strip secured to the upper surface of the armature 32, provides one contact-making surface 31 for engagement with the stationary contact 38 in one position of the armature and a second contact-making surface 39 for engagement with the stationary contact 4
  • the contact strip has a depending portion 4
  • the mercury 42 rests in -a small spherically shaped cavity formed in the bottom of the container 30.
  • the different parts of the armature 32 are so proportioned that the armature normally rests in the position shown in Fig. 12 to engage the stationary contact 40.
  • the projecting arm 52 rests on the surface of the pool and counteracts any tendency the mercury may have to pull down on the immersed member 4
  • the stationary contact 38 is illustrated as a tube and may be used for the purpose of evacuating the interior ofthe relay container 3U. If desirable, however, the contact 38 may be a solid member similar to contact 40, and the tube may be evacuated by other means.
  • a suitable magnetic operating structure for the relay shown in Figs. 12 to 16 is illustrated in Fig. 17. It includes an operating coil 43 wound on a core to which the magnetic members 44 and 45 are secured, the non-magnetic member 46 being provided as a part of the assembly to hold the different parts in place.
  • a nonfmagnetic plate 4 1 is shaped to receive and hold the container 30 in position.
  • Each of the relays described herein is constructed to take full advantage of the forces of capillarity to maintain a coating or film of mercury on the contact-making surface of the movable and stationary contacts.
  • the capillary action may be enhanced by making the translating member of certain materials, such as platinum, nickel and copper, or by coating it with these materials, and by including inert gases in the container to prevent corrosion of the contact surfaces.
  • This feature is particularly important where small operating currents are involved, such as those encountered in telephone and telegraph systems.
  • the housing tubes may be made in various shapes and sizes; the armatures may vary in their shapes and proportions; the shapes and location of the stationary and movable contacts may also be varied; and numerous variations of the magnetic structure may be employed.
  • the chamber within the housing tube or container may be supplied with any suitable gas for preserving the contacts and for improving the operation of the relay.
  • a housing having a pool of mercury therein, an armature mounted in said housing, a movable contact actuated by said armature, a stationary contact projecting into said pool and serving as a transfer means to attract the mercury by capillary action out of said pool and onto the contact-making surface of said stationary contact, and means for moving said armature to effect engagement and disengagement between said movable contact and the contact-making surface of said stationary Contact.
  • an electric switch a closed housing tube having a pool of mercury in the bottom thereof, a magnetic armature mounted in said tube for movement under the influence of a magnetic field, a movable contact secured to said armature, a stationary contact extending into said pool of mercury and having a contact-making surface disposed above the level of said mercury in said pool, said stationary contact serving to attract the mercury from the pool to cover said contactmaking surface, and an energizing coil for operating said armature.
  • a housing member a pool ci mercury in said housing member, an armature, means for operating said armature without displacing the mercury in said pool, an electric contact having an engagement surface for opening and closing an electric circuit in response to the movement of said armature, and
  • a container having a pool of mercury therein, an armature formed from a thin strip of magnetic material and mounted within said container, said armature having a series of transverse cuts forming a spring portion for restoring the armature to its normal position, movable and stationary contacts having contact-making surfaces for engagement in response to the movement of said armature, one of said contacts serving to attract mercury out of said pool and onto said contactmaking surfaces, and electromagnetic means for operating said armature.
  • armature mounted in said housing, stationary 5 and movable contacts having contact-making surfaces for closing and opening an electric circuit, means for moving said armature to effect HENRY C. HARRISON.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Contacts (AREA)
US340652A 1940-06-15 1940-06-15 Electric switch Expired - Lifetime US2302546A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL132811D NL132811B (enrdf_load_stackoverflow) 1940-06-15
NL66974D NL66974C (enrdf_load_stackoverflow) 1940-06-15
US340652A US2302546A (en) 1940-06-15 1940-06-15 Electric switch
DEW907D DE895183C (de) 1940-06-15 1941-08-05 Elektrische Schaltvorrichtung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US340652A US2302546A (en) 1940-06-15 1940-06-15 Electric switch

Publications (1)

Publication Number Publication Date
US2302546A true US2302546A (en) 1942-11-17

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ID=23334366

Family Applications (1)

Application Number Title Priority Date Filing Date
US340652A Expired - Lifetime US2302546A (en) 1940-06-15 1940-06-15 Electric switch

Country Status (2)

Country Link
US (1) US2302546A (enrdf_load_stackoverflow)
NL (2) NL132811B (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2508508A (en) * 1946-08-10 1950-05-23 Bell Telephone Labor Inc Mercury contact for electrical switches
US2519463A (en) * 1946-08-09 1950-08-22 Bell Telephone Lab Incorproate Mercury type relay
US3290615A (en) * 1965-06-23 1966-12-06 Peter K Ludwig Mercury-wetted fixed electrode electric arc generator
US4804932A (en) * 1986-08-22 1989-02-14 Nec Corporation Mercury wetted contact switch

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2519463A (en) * 1946-08-09 1950-08-22 Bell Telephone Lab Incorproate Mercury type relay
US2508508A (en) * 1946-08-10 1950-05-23 Bell Telephone Labor Inc Mercury contact for electrical switches
US3290615A (en) * 1965-06-23 1966-12-06 Peter K Ludwig Mercury-wetted fixed electrode electric arc generator
US4804932A (en) * 1986-08-22 1989-02-14 Nec Corporation Mercury wetted contact switch

Also Published As

Publication number Publication date
NL66974C (enrdf_load_stackoverflow)
NL132811B (enrdf_load_stackoverflow)

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