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Publication numberUS2445406 A
Publication typeGrant
Publication dateJul 20, 1948
Filing dateJul 21, 1944
Priority dateJul 21, 1944
Publication numberUS 2445406 A, US 2445406A, US-A-2445406, US2445406 A, US2445406A
InventorsPollard Jr Charles E
Original AssigneeBell Telephone Labor Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Circuit maker and breaker
US 2445406 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

July 20, 1948. c. POLLARD, JR


ATTORNEY Patented July 20, 1948 CIRCUIT MAKER AND BREAKER Charles E. Pollard, Jr., Hohokus, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application July 21, 1944, Serial No. 545,896

3 Claims. 1

This invention relates to circuit makers and breakers and especially to sealed contact devices of the type employing liquid mercury.

It is the object of the invention to provide a mercury pool contact device which will operate equally well in any given position. It has long been known that mercury contacts or mercury wetter contacts have many desirable properties and advantages but the great drawback to the use of such contacts has been the necessity for maintaining a pool of mercury which has meant that the contact device could be mounted in but a single position. It is therefore the object of the present invention to provide a contact device which is not subject to this disadvantage.

In accordance with the present invention a pool of mercury is maintained in a sponge of metallic fibers which are wettable by the mercury so that the mercury is held in this sponge regardless of the position in which it may be placed. I

A feature of the invention is a suspended pool of mercury held at a given location through the forces of surface tension.

Another feature of the invention is the use of a mercury wettable sponge for maintaining a pool of mercury at a given location regardless of the position to which the sponge may be turned at any given time.

Another feature of the invention is the use of a mercury trap, constructed and arranged to maintain a pool of mercury in space but of insufiicient force to defeat the use of mercury from said pool upwardly and along a mercury wick dipped in said pool.

Another feature of the invention is the combination consisting of the magnetically movable contacts having mercury wetted surfaces maintained wetted with mercury by a wick dipped in a pool of mercury held in space by a mercury wetted sponge.

The drawings consists of a single sheet having three figures as follows:

Fig. 1 is a cross-sectional view of a sealed contact device employing the novel features of the present invention;

Fig. 2 is one type of mercury sponge; and

Fig. 3 is an alternative type thereof.

The contact used consists of an envelope I of glass or other suitable material. In the lower end of this unit a tube 2 is sealed through the press 3. In the upper end two electrodes 4 and 5 are sealed through the upper press 6 in similar manner. The tube 2 is used as a support for the moving armature of the switch. Thus a spring I is welded to the upper end of the tube 2 and has in turn attached to it a magnetic armature 8. A mercury wick 9 is secured to the armature 8 and extends downwardly to a point near the upper end of the tube 2. Secured to the upper end of tube 2 there is a mass I0 of metallic fibers wettable by mercury and which constitute a mercury sponge so that the lower end of the-wick 9 will be submerged in a pool of mercury. This construction has the advantage that the mercury sponge ill will be saturated with mercury and willthus hold a pool of mercury at this point regardless of the position in which the device is turned. This therefore overcomes one great disadvantage of mercury contact switching devices which has heretofore required that they be always held in a particular position.

The two electrodes 4 and 5 extend into the interior of this device and have secured thereto the contact arrangements l I and I2 respectively, each having secured thereto a small cross piece of contact material l3 and I4 respectively. These contact pieces are wettable by mercury and therefore present'a constantly renewed clean contact surface of low resistance. a

One form of the mercury sponge is illustrated in Fig. 2 and this consists of a piece of fine mesh screen l5 rolled into the form shown and secured to the supporting tube l6 by any appropriate means. This screen is of a material which is wettable by mercury.

Another form of the invention is shown in Fig. 3 where a mass of fibers H such, for instance, as those known as steel wool, are used. This may be held together by a band l8 and the whole secured to the supporting tube IS in any appropriate manner.

The term "mercury wic used herein denotes an arrangement of a pair of metal wires or a metallic element having grooves between which or in which the mercury will rise above the level of the pool by capillary action and entails the use of mercury wettable surfaces.- A mercury wick forms part of the subject-matter of my Patent Number 2,259,661, granted October 21, 1941. Metallic fibres are, filaments or wires of metal such as iron, steel, brass, copper nickel or of various alloys, a good example of which is the tangled mass of such material known widely as steel wool.

What is claimed is:

1. A contact device having mercury wetted contacts, a mercury-wettable sponge, a pool of mercury trapped in said sponge and a mercury wick for feeding said contacts from said pool.

A contact device having mercury wetted con- REFERENCES crmn The following references are of record in the flle of this patent:

Number Number UNITED STATES PATENTS Name Date Pollard Oct. 21, 1941 Harrison June 30, 1942 McCabe Aug. 3, 1943 FOREIGN PATENTS Country Date France May 22, 1924

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2259661 *Jun 15, 1940Oct 21, 1941Bell Telephone Labor IncElectrical switch
US2288452 *Jun 15, 1940Jun 30, 1942Bell Telephone Labor IncElectric switch
US2325785 *Apr 27, 1942Aug 3, 1943Mccabe Ira EEnclosed mercury switch
FR576839A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2609464 *Oct 5, 1949Sep 2, 1952Bell Telephone Labor IncRelay
US2766396 *May 26, 1953Oct 9, 1956English Electric Valve Co LtdDevices having fragile envelopes partly filled with mercury
US2769875 *Sep 25, 1953Nov 6, 1956Bell Telephone Labor IncMercury contact switch
US2797329 *Nov 4, 1954Jun 25, 1957Research CorpMercury contact switch impulse generator
US2837612 *Feb 18, 1955Jun 3, 1958Bell Telephone Labor IncMercury switches
US2844687 *Aug 3, 1956Jul 22, 1958Gottfried Arthur HElectromechanical switching element
US2868926 *Jun 25, 1957Jan 13, 1959Bell Telephone Labor IncSwitch
US3114020 *May 5, 1961Dec 10, 1963Beckman Instruments IncHigh resolution digital position transducer including a magnetic switch
US3116384 *Nov 2, 1961Dec 31, 1963Bell Telephone Labor IncMethod of conditioning and all-position mercury switch
US3147538 *May 16, 1961Sep 8, 1964Sylvania Electric ProdMethod of fabricating mercury-wetted switching devices
US3238525 *Jan 19, 1962Mar 1, 1966Wheelock Signals IncVibrating mechanism
US3246321 *Feb 28, 1962Apr 12, 1966V & E Friedland LtdElectrical signaling devices
US3343110 *May 11, 1966Sep 19, 1967Int Standard Electric CorpAdhesive relay
US4114006 *May 3, 1977Sep 12, 1978Western Electric Co., Inc.Mercury-wetted sealed contact switch
US4208643 *Jun 5, 1978Jun 17, 1980Gulf & Western Manufacturing CompanyMagnetically actuated mercury switch
US4668927 *Mar 6, 1986May 26, 1987American Telephone & Telegraph Co., At&T Bell LabsRelay switch apparatus
DE948174C *Jun 12, 1953Aug 30, 1956English Electric Valve Co LtdEinrichtung mit einem zerbrechlichen Quecksilbergefaess
DE1690789B1 *Oct 20, 1962Mar 19, 1970Western Electric CoLageunabhaengiger Quecksilberzungenschalter und Verfahren zu seiner Herstellung
WO1990002409A1 *Aug 24, 1989Mar 8, 1990Radomir JanusSwitch with contacts wetted with mercury
U.S. Classification200/191, 200/234, 439/894, 335/58
International ClassificationH01H51/28, H01H51/00, H01H1/08, H01H1/06
Cooperative ClassificationH01H51/287, H01H1/08
European ClassificationH01H51/28F, H01H1/08