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Publication numberUS2247493 A
Publication typeGrant
Publication dateJul 1, 1941
Filing dateNov 2, 1939
Priority dateNov 2, 1939
Publication numberUS 2247493 A, US 2247493A, US-A-2247493, US2247493 A, US2247493A
InventorsHarrison Henry C, Pollard Charles E
Original AssigneeBell Telephone Labor Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Mercury contact relay
US 2247493 A
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Description  (OCR text may contain errors)

Jui? 1' 1.941- H. c. HARRISON E-rAL 2,247,493

MERCURY CONTACT RELAY Filed Nov. 2, 1939 Patented July 1, 1941.

MERCURY CONTACT RELAY 1 Henry C. Harrison, Port Washington, N. Y., and Charles E. Pollard, Hohokus, N. J., assgnors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application November 2, 1939, Serial No. 302,526

'(Cl. 20G- 112) 11 Claims.

This invention relates to electromagnetic devices and more particularly to relays in which circuits between the contact terminals thereof are established by means of mercury.

Switches in which circuits are established bcv tween contact terminals through the m'edium of mercury possess many advantages over switches ofthe contact spring type in that the tendency of arcing of the contacts and the consequent Contact deterioration is reduced; the tendency of Contact chatter is much reduced or practically eliminated; the current carrying capacity is materially increased without requiring a great increase in the size oi' the switch; a smaller operating current is required; the switch is readily adaptable for delayed circuit closing or opening or for providing many contact combinations required for circuit control such as transfer contacts, continuity contacts, etc., and a plurality of such switches having different time constants may be easily assembled for operation by the same electromagnetic means.

It is therefore the objectJ of the present invention to provide electromagnetically operated switches of the mercury contactl type in which the above speciiied and other advantages are readily and economically attained.

For attaining this object and in accordance With one embodiment of the present invention a small envelope of glassor other suitable material is provided in which a light plunger armature of magnetic material is slidably positioned and which supports a globule of mercury. Sealed irrtoone end of the envelope are two or more inwardly extending contact terminals or electrodes which may be bridged by the globule of mercury. .Preferably to reduce the deterioration of the contacts and the contamination of the mercury, the envelope is evacuated and relled with an inert gas, such as hydrogen, neon, argon, etc. at a suitable pressure. For securing diiierent types of contact closures, suchA as for example, quick make-quick break, quick make-slow break, and slow make-quick break and diierent types of contact openings, such as quick break-quick make, slow break-quick make and quick .breakslow make, ceramic insulators of diierent configur-ations may be supported by the electrodes in one end of the envelopes or the depending ends disposed pole-pieces of an electromagnetic circuit,l although it will be apparent that other types of magnetic circuits, such as a solenoid coil surrounding the envelope might; be employed. It will also be apparent that a plurality of switches having different operating characteristics. could have their plunger armatures Iactuable by a common magnetic circuit by providing a plurality of aligned openings in the poleypieces of the magnetic circuit in which such switches are positioned.

As an alternative construction the envelope may contain a pool of mercury in the bottom thereof in which one of the depending electrodes is immersed and the other electrode may be terminated in a coil of magnetic material which when subjected to a magnetic iield either contracts or expands to break or make contact With the pool of mercury.

For a more complete understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing in which:

Fig. 1 shows a relay having a plurality of mercury type switch elements;

Fig. 2 is a partial cross-sectional View of one of the switch elements arranged for a quick make-quick break of its normally open contacts;

Fig. 3 is a side elevational view and Fig. 4 is a bottom end view of the ceramic insulator of the switch disclosed in Fig. 2;

Fig. 5 is a cross-sectional view of a modified type of ceramic insulator;

Fig. 6 is a partial cross-sectional View of a switch element arranged for a quick make-slow break of its normally open contacts;

Fig. 7 is a partial cross-sectional view of a switch element arranged for a slow make-quick break of its normally open contacts;

Fig. 8 is a partial cross-sectional View of a switch element arranged for a quick breakquick make of its normally closed contacts;

Fig. 9 is a partial cross-sectional` view of a switch element arranged for a slow break-quick make of its normally closed contacts;

Fig, 10 is a partial cross-sectional view of a switchelement arranged for a quick break-slow make of its normally closed contacts;

Figs. 11 to 14, inclusive, show modied forms of lswitch elements arranged for quick recycling of which the element of Fig. 11 is arranged to close its contacts slowly and to open them quickly; the element of Fig. 12 is arranged to close certain of-its contacts quickly, tovclose other contacts slowly and to open all of its contacts quickly; the element of Fig. 13 is arranged to open its normally closed contacts quickly and to close Ithem slowly; and the element of Fig. 14 is arranged to open all of its normally closed contacts quickly and to close certain of them quickly and others of them slowly;

Fig. 15 is a cross-sectional view of the envelope used in switch elements of the types disclosed in Figs. 6, 'T and 9 to 14, inclusive;

Fig. 16 shows a modified type of switch element in which a conductive path through a pool of mercury is established by the elongation of a coil of magnetic-spring material under the influence of a magnetic circuit; and

Fig. 17 shows the switch element of the same type as disclosed in Fig. 16 in which a normally established path through a pool of mercury is disrupted by the construction of a coil of magnetic spring material.

A relay employing switch elements of the mercury contact type is disclosed in Fig. 1. This relay comprises a core I to the forward end of which is suitably secured a pole-piece plate 2 and to the rear end of which is secured a forwardly extending return pole-piece 3. The return pole-piece is offset in its middle portion to provide clearance for the relay winding 4 surrounding the core I, is bent at right angles at its rear end to form a mounting bracket portion 5 by which the relay may be secured to a relay rack mounting plate and has its forward end 6 positioned parallel to and suitably spaced from the pole-piece plate 2. Secured by screws I and in sulatedly supported upon the rear end of core I are terminal lugs 8 and 9 to which the terminals of the coil 4 are connected. Other terminal lugs may be provided, if desired, for connection with the electrodes of the switch elements supported by the pole-pieces as hereinafter described. `As illustrated the pole-pieces 2 and 6 are provided with aligned openings in which four mercury contact switch elements are positioned. It will, of course, be obvious that provision may be made for a single switch element or any desired number of such elements.

The switch elements may be of any of the types disclosed in Figs. 2, 6 to 14, inclusive, 16 and 17. The switch elements disclosed in Figs. 2 and 6 to 10 each comprises an envelope I0 made of glass or any other suitable material which will not amalgamate with the mercury enclosed therein, two electrodes II and I2 sealed through one end thereof andextending into the inside of the envelope, a plunger armature I3 of magnetic material supported upon a spring I4 positioned in the bottom of the envelope, the plunger being of slightly smaller diameter than the inside diameter of the envelope whereby it is free to slide within the envelope, a globule of mercury I5 positioned adjacent to one face of the plunger and an insulating cylinder I6 preferably of porous unglazed ceramic material not easilycontaminatedby the mercury supported upon electrodes Il and I2 in one end of the envelope.

The insulating cylinder I6 for the switch element of Fig. 2, disclosed in detail in Figs. 3 and 4,

is provided with two holes extending longitudinally thereof through which the switch electrodes may extend, the electrodes fitting tightly enough in such holes to support the cylinder securely in the desired position in the upper end of the envelope. The lower end of the cylinder is cut away as indicated to provide a half cylindrical recess II for a purpose to be later described.

As disclosed in Fig. 2, the plunger I3 is nor` mally so positioned within the envelope that when the switch element is mounted in the aligned openings of the pole-pieces 2 and 6 of the electromagnet, its upper surface will be substantially in the plane of the upper face of the pole-piece 6 in which position the globule of mercury I5 is engaged with the end of the electrode I2. When, however, a magnetic potential is established between the pole-pieces 2 and 6, a flux path will be established through the plunger I3 and the plunger will be drawn upwardly in the envelope in an attempt to center itself between the polepieces 2 and 6. This movement of the plunger moves the globule of mercuryA upwardly, a tongue of the mercury being forced into the recess I`I of the insulating cylinder IB until it engages the end of electrode II which extends downwardly into the recess. Since the recess is shallow and the electrode II extends nearly to the lower end thereof, the movement ol` the mercury globule effects quick closure between the electrodes II and I2. Reversely when the pole-pieces 2 and 5 become demagnetized, the plunger I3 is freed to drop upon the upper end of spring I4 which in this case serves as a shock absorber and the tongue of mercury will be withdrawn quickly from the recess Il due to the spring action of the surface tension of the mercury, thus forcing the plunger downwardly and effecting a quick opening between the `electrodes II and I2. This switch element thus affords a quick make-quick break of normally open contacts.

The switch element disclosed in Fig. 8 is substantially similar to that Adisclosed in Fig. 2 except that the insulator I6 is shorter and spring I4 is expanded to normally hold the plunger I3 in the position disclosed, whereby the globule of mercury I5 is normally in contact with the ends of both electrodes II and I2 thus effecting a normal circuit closure. When, however, a magnetic potential is created between the pole-pieces 2 and 6, the plunger I3 will be drawn downwardly in the envelope to compress the spring I4 and due to its surface tension the tongue of mercury will withdraw quickly from the recess I'I thus quickly opening the contact between the mercury and the electrode II. Reversely when the polepieces become demagnetized, the plunger is quickly forced upwardly by the spring I4 to force a tongue of mercury into the recess I1 to again effect a circuit closure. This switch element thus 'affords a. quick break-quick make of normally closed contacts.

The switch element of Fig. 6 is substantially the same as that disclosed in Fig. 2 with the exception of the arrangement of electrodes II and I2 with respect to the recess in the insulator I6. In this case the recessed portion I1 of the insulator is made much deeper and the depending Vend of electrode II extends substantially to the lower end of the recessed portion II. When the plunger I3 is electromagnetically actuated toward the upper pole-piece 2, a tongue of mercury from the globule I5 is forced into the recess I1 and quickly engages the end of electrode II, thus effecting a quick contact closure. As the plunger moves upwardly the tongue of mercury becomes extended until it completely fills the recess. Reversely when the pole-pieces are demagnetized and the plunger I3 drops down upon the buffer spring I4 the surface tension of the mercury globule will tend to withdraw the tongue of mercury from the recess l1. To delay this action the envelope is provided with a capillary groove I3, shown most clearly in Fig. 15, in the wall of the envelope opposite the recessed portion Il of insulator I6 through which the .gas flows slowly the depending portion of electrode II protrudesv for only a short distance below the top of the recessed portion I1 of the insulator I6. When the plunger I3 is electromagnetically actuated towards the pole-piece 2, the tongue of mercury from the globule I5 is forced into recess I1 but due to the slow flow of gas through the capillary groove I8, past the mercury globule, the time required for the tongue to'completely fill the recess and engage the end of electrode II is extended, thus effecting a slow closure between the electrodes II and I2. Reversely, when the polepieces are demagnetized and the plunger I3 is freed to drop down upon the buffer spring Il, the end of the tongue of mercury will, due to the surface tension of the mercury withdrawn from the end of electrode II, quickly thus forcing the plunger downwardly and effecting a quick break between the electrodes. This switch element thus affords a slow make-quick break of normally open contacts.

The switch element of Fig. 9 is substantially the same as that disclosed in Fig.8 except that the capillary groove I8 is provided, the recess I'I in the insulator I6 is made deep and the dependpole-pieces are thereafter demagnetized, the plunger I3 will at first be restored quickly by the spring I4 and will tend to force a tongue of mercury into the recess I1. 'The further restoring movement of the plunger will then be delayed by the slow extension of the tongue of mercury into the recess as determined by the ilow of gas through the groove I8, until finally the end of the tongue engages the end of! electrode II to reestablish the contact between the electrodes II and I2 through the mercury. This switch element thus affords a quick break-slow make of normally closed contacts.

, As an alternative the semicylindrical recess I1 of the insulator may be omitted as disclosedln Fig. 5 and the electrode II may be extended different distances through the hole in the insulator IB dependent upon the circuit closing or opening characteristic desired, the remaining portion of vthe hole I1' below the lower end of electrode II serving as a recess into or from which the tongue of mercury is forced or withdrawn.

While the switch elements shown in Figs. 2 to 10, inclusive, have been illustrated aspositioned ing end of electrode II extends throughout the entire length of the recess. Normally the plunger `I3 is held in the position shown by the spring I4 s o that a tongue of .the mercury globule I5 is forced up into and completely lls the recess,

thus electrically connecting the electrodes Il and f I2. When the plunger I3 is electromagnetically drawn against the tension of spring Il toward the pole-piece 6, the tongue of mercury will tend 'A to withdraw from the recess but will be retarded in its withdrawal by the slow flow of gas through the grooveg I8 and since the tongue of mercury will engage the end `of electrode II until it is entirely withdrawn from the recess, a slow break between the 'electrodes II and I2 is effected. When the pole-pieces become demagnetized, however, the plunger I3 will first be restored rapidly by the spring I4 thereby quickly engaging the mercury globule I5 with the ends of electrodes II and I2 and will thereafter move more slowly until a tongue of mercury again lls the recess I1. This switch element thus affords a slow breakquick make of normally closed'contacts.

The switch element of Fig. 10 is also substanftially similar to that of Fig. 9 with the exception 'that the depending endof electrode II extends but a short distance into the recess I1 of the insulator I6. In the normal position of `the plunger I3 as disclosed, a tongue of the mercury globule is forced into and completely fills the jrecess, thuspconnectig the ends of the electrodes. When theeplunger I3 is electromagnetically drawn downwardlytoward the pole-piece 6, the tongue' of mercury will tend to withdraw from the recess.

but will be retarded in its withdrawal by the slow `flow of gas through the groove IB but vsince the.

tirely.` withdraw from the recess. Wheri the vertically with their plungers in the lower portions thereof, these elements will function if in. verted or positioned horizontally.

Figs. 11 to 14, inclusive, disclose switch elements which are not provided with insulating cylinders in the upper portion of the envelopes whereby more space is provided in the upper portion of the envelopes to enable a luickerrecycling through the more rapid collapse of the globules of mercury. Figs. 11 and 12 disclose switch elements having normally open contacts and Figs. 13 and 14 disclose switch elements having normally closed contacts.

In accordance withFig. 11 upon the magnetization of the pole-pieces 2 and i, the plunger I3 is drawn upwardly toward the pole-piece 2, thus raising the'globule of mercury I5 into engagement with the ends of electrodes II and I2. 'Ihe movement of the globule is, however, delayed due Yto the slowv passage of gas through the capillary Amake-quick break of normally open contacts.

In accordance with Fig. 12, threeelectrodes I II, I2 and I9 are provided, electrodes II and I2 terminating just above the upper surface of the mercury globule I5 and the electrode Il terminating at a greater distance above the surface of the globule. When the pole-pieces 2 and 6 become magnetized, the plunger I3 is drawn up` wardly toward the pole-piece 2 thus raising the globule of mercury into engagement with the, ends of electrodes/ II and I2 to effect a quick closure between them. 'I'he further movement of the globule is, however, delayed due to the slow passage of gas through the capillary groove I! past the globule whereby a slow closure between the electrodes II' or I2 and electrode I9 is, effected. When the pole-pieces are demagnetized, the plunger drops down upon the buffer spring I4 and the globule collapses quickly to disengage all of the electrodes. This switch element therefore' affords both a quick and slowl make and' a quick break of its normally open contacts.

The switch element of Fig. 13 is so constructed that plunger 13 is 'normally held in the position disclosed by the spring Il in\whlch position the globule of mercury I makes contact with the ends of electrodes II and I2. When the polepieces 2 and 6 become magnetized, the plunger is drawn downwardly toward the pole-piece E thereby compressing the spring I4 and quickly withdrawing the mercury from engagement with the electrodes. Upon the later demagnetization of the pole-pieces the spring I4 tends to restorethe plunger to its normal position, but is delayed in doing so by the slow leak of gas past the globule through the capillary groove I8. A delay interval is thus introduced before the plunger rises sufliciently to move the globule of mercury into engagement with the electrodes. This switch element therefore affords a quick break and a slow make of itsnormally closed contacts.

The switch element of Fig. 14 is similar to thatl of Fig. 13 except that three electrodes II, I2 and I9 are provided, the ends of electrodes II and I2 being normally deeply immersed in the mercury globule I5 and the end of electrode I9 being less deeply immersed. In the operation of this switch element when the pole-pieces 2 and 6 become magnetized and the plunger I3 is drawn toward the pole-piece 6, against the tension of spring I4, the mercury globule I5 follows it to quickly disengage all of the electrodes. When thereafter the pole-pieces become demagnetized, the spring I4 tends to restore thplunger to its normal position but is delayed in doing so by the slow leak of gas past the globule through the capillary groove I8. Due, however, to the fact that electrodes II and I 2 are long and in the operated position of `the plunger their ends are close to the upper surface of the globule, the first part of the restoring movement of the plunger will quickly bring the globule into engagement with the ends of such electrodes, but electrode I9 being much shorter will not be engaged by the globule until near the end of the restoring movement of the plunger. This switch element thus provides a quick break of all of its normally closed ucontacts, a quick make between certain of its contacts and a slow make between other of its contacts. y

In Figs. 16 and 17 a further embodiment of thev invention has been disclosed in each of which the globule of mercury I5 is deposited in the bottom of envelope I0 and one of the electrodes 2l) has its end immersed in the globular, The other electrode 2l is made of magnetic spring material or has.l that portion thereof depending Within the envelope made of such material and provided with a helix 22.

The switch element disclosed in Fig. 16 is of the normally open circuit type. The electrode 2l thereof extends downwardly to a point above the lower pole-piece S and is then coiled upwardly about the downwardly extending portion to form the closely coiled helix portion 22, with the end of the electrode extending from the top coil of the helix downwardly through the helix and terminating just above the upper surface of the'mercury globule. When the pole-pieces 2 and 6 become magnetized, the lower portion of the helix is drawn toward the lower pole-piece 6 thereby moving the lower end of the electrode 2| into engagement with the mercury to quickly establish a circuit through the mercury between the electrodes 2U and 2I. When the pole-pieces become demagnetized, the helix contracts quickly and withdraws the end of electrode 2l from the mercury thus opening the connection between the electrodes. v

The switch element of Fig. 17 is of the normally closed circuit type and therefore the end of the electrode 2I is normally immersed in the mercury globule I5. The helix 22 there of has its coils loosely wound. When therefore the polepieces 2 and 6 become magnetized, the adjacent coils of the helix 22 become attracted toward each other thereby contracting the helix to such an extent as to disengage the end of electrode 2I from the mercury to effect a circuit opening. Thereafter, upon the demagnetization of the pole-pieces the helix expands to again engage the end of electrode 2I with the mercury.

While the invention has been illustrated by certain specific embodiments thereof, other ar-4 rangements of electrodes and magnetically actuated members and the association of the globules of mercury therewith for securing other types of circuit control will be apparent to those skilled in the art. It is therefore to be understood that the scope of the invention is limited only by the bounds set forth in the appended claims.

What is claimed is:

1. In an electromagnetic structure having an electromagnetic field, a contact element comprising a sealed envelope, terminals extending into said envelope, a plunger of magneticmaterial responsive to said electromagnetic field and freely movable in said envelope and a globule of mercury supported on the end of said plunger in engagement with the inner wall of said envelope and movable thereby to control the bridging of said terminals.

2. In anelectromagnetic structure having an electroma gnetic field, a contact element comprising a sealed envelope, terminals extending into said envelope, a plunger of magnetic material responsive to said electromagnetic field and freely movable in said envelope and a globule of mercury supported on the end of said plunger in'engagement with the inner wall of said envelope and movable thereby into bridging engagement with said terminals.

3t In an electromagnetic structure having an electromagnetic field, a contact element comprising a sealed envelope, terminals extending into said envelope, a plunger of magnetic material responsive to said electromagnetic field and freely movable in said envelope and a globule of mercury supported on the end of plunger in engagement with the inner Wall of said envelope and movable thereby out of normal bridging engagement with said terminals.

4.' In an electromagnetic structure having an electromagnetic field, a contact element comprising a sealed envelope,` an insulator supported in one end of said envelope, the inner end of which is provided witha recessed portion, a pair of terminals of different lengths extending through the end wall of said envelope and through said insulator, the inner end of the longer terminal being exposed beyond' the inner end of said insulator and theinner end of the shorter terminal being exposed in the recessed portion of said insulator, a plunger of magnetic material responminals of different lengths extending through insulator, the inner end of the longer terminal being exposed beyond the inner end of said insulator and the inner end of the s orter terminal being exposed in said recessed portion of said insulator, a-plunger of magnetic' material responsive to said magnetic field and freely movable in said envelope and a globule of mercury associated with said plunger normally in engagement with said longer terminal and movable 'by said plunger into the recessed portion of said insulator into engagement with said shorter terminal. 1 f

6. vIn an electromagnetic structure vhaving an electromagnetic field, a contact element comprising a sealed envelope, an insulator supported in one end offsaid envelope, the inner end of which isprovided with a recessed portion, a pair of terminals of different lengths extending through the end wall of said envelope and through said insulator, the inner end of the longer terminal being exposed beyond the inner end of said insulator and the inner'end of the shorter terminal being exposed in said recessed portion of said insulator, a plunger of magnetic material responsive to said magnetic field and freely movable in said envelope and a globule of mercury associated with` said plunger normally in engagement with the inner end of said insulator and filling the recessed portion thereof to bridge sjaid termina1s, saiduglobule being movable by the "attr-acted movement of said plunger out of engagement With said Iterminals.

7. In an electromagnetic structure having an electromagnetic field, a contact element comprisingl a sealed envelope, an insulator supported in one end of said Yenvelope the inner'end of which is provided with a deeply recessed portion, a pair of terminals vofdiiferent lengths extending through the end Wall of said envelope and through said. insulator, the inner end of the longer terminal. being exposed beyond the inner end of said insulator and"`the inner end of the shorter terminal exten `ng substantially throughout the length of saidl recessed portion of said insulator, a plunger of magnetic material responsive to said magnetic -el'l and'freely Vmovable lin said envelope, a globule of mercury prising a sealed envelope, an insulator supported in one end of said envelope, the inner end of which is provided witha deeplyrecessed portion, a pair of terminals of different lengths extending through the end wall of said envelope and through said insulator, the inner end of the longer terminal being exposed beyond the inner end of said insulator-and the inner end of the 'shorter terminal being exposed,only just beyond the bottom of the recessed portion of said insulator, 4a plunger of magnetic material respon- G sive to' said magnetic field and freely movable in said envelope, a globule of mercury associated with said plunger and movable thereby to control the bridging of said terminals and a capillary groove in the inside wall of said envelope for controlling the rate of movement of said globule of mercury. f

9. In an electromagnetic structure having an electromagnetic iield, a. contact element comprising a sealed envelope, an insulator supported in one end of said envelope, the inner end of which is provided with a deeply recessed portion, a

pair of terminals of diierent lengths extending through the end wall of said envelope and through said insulator, the inner end of the longer terminal being exposed beyond the inner end of said insulator and the inner end of the shorter terminal extending substantially the length ofvsaid recessed portion of said insulator, ,a plunger of magnetic material responsive to said magnetic field and freely `movable,in said envelope, a globule of mercury associated with said plunger and n mally in engagement with said longer terminal and movable by the attracted movement of said plunger 'into the recessed portion of said insulator into engagement with said shorter terminal, and a capillary groove in the inside wall of said envelope for delaying the flow of said mercury glouble from the recessed porition of said insulator upon the retractive move,- ment of said plunger.

10. In an electromagnetic structure having an electromagnetic field, a contact element comprising a sealed envelope, an insulator supported in one end of said envelope, the inner end of which is provided' with a deeply recessed portion, a'pair of .terminals of different lengths extending lthrough the end Wall of said lenvelope and through said insulator, the inner end of the longer terminal-being exposed beyond the inner end of said insulator and the inner end of the shorter terminal extending substantially the length of said recessed portiony of said insulator, a Aplunger of magnetic material responsive to said magnetic eld and freely movable in said envelope, a globule of mercury associated with said plunger normally in engageme t with the inner end of said insulator and lling he recessed portion thereof to bridge said terminals, said globule of mercury being movable by tlze attracted movejment of said plunger out of engagementiwith said terminals and a capillary groove in the inside wall of said envelope for delaying the ow of,

said mercury globule from said recessed portion upon the attracted movement of said plunger.

11. In an electromagnetic structure having an electromagnetic field, a contact element comprlsing a sealed envelope, Aan insulator supported in one end of said envelope, the innenend of which sulator, a plunger of magnetic material responsive to said magnetic field' and freely 4movable in said envelope, a globule of mercury associated with said plunger normally in engagement vwith said longer terminaland movable .by the atI tracted movement of said plunger into the :recessed portion of said insulator inlto engagement with said shorter terminal and a capillary groove in the inside wall of said-envelope for delaying thejow 'of said mercuryglobule into said recessed portion lof said insulator.

HENRY C. HARRISON. CHARLES E. POLLARD.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2472048 *Nov 1, 1943May 31, 1949Joy Mfg CoElectric circuit controller
US2542668 *Aug 14, 1946Feb 20, 1951Bell Telephone Labor IncMercury type relay
US2974211 *Mar 23, 1959Mar 7, 1961Brede Erwin FElectric switches
US3344373 *Feb 7, 1966Sep 26, 1967Automatic Elect LabSwitching device employing a globule of magnetizable electrically conductive fluid
US3462573 *Oct 14, 1965Aug 19, 1969Westinghouse Electric CorpVacuum-type circuit interrupters using gallium or gallium alloys as bridging conducting material
US4366458 *Dec 3, 1981Dec 28, 1982Elenbaas George HMercury displacement relay
US4400671 *Jan 6, 1981Aug 23, 1983Thomson-CsfMagnetically controlled mercury wetted switch and electrical relay incorporating such a switch
DE1088129B *Jan 10, 1958Sep 1, 1960Robertshaw Fulton Controls CoMagnetisch betaetigter Quecksilberschalter kleiner Abmessungen
DE1105956B *Mar 20, 1958May 4, 1961Joseph EvangelistaWaehlschalter mit durch eine Schablone gesteuertem Quecksilber
Classifications
U.S. Classification335/51, 335/48
International ClassificationH01H29/00, H01H51/00, H01H51/28, H01H29/18
Cooperative ClassificationH01H51/287, H01H29/18
European ClassificationH01H51/28F, H01H29/18