US2091424A - Fuse - Google Patents

Description

AU@ 3l, 1937- H. A. TRlPLr-:T'r 2,091,424

FUSE

Filed May 13, 1955 4 Sheets-Sheet 1 Aug. 31, 1937.

H. A. TRIPLETT 2,091,424

FUSE

Filed May 13, 1933 4 Sheets-Sheet 2 A8 3l 1937 H. A. TRIPLETT 2,091,424

FUSE

Filed May 13, 1935 4 Sheets-Sheet 3 fRoI/S Aug. 31, 1937.

Filed May 13, 1935 H` A. TRIPLETT FUSE 4 Sheets-Sheet 4 Patented Aug. 3l, 1937 PATENT oFFlcE FUSE Hugh A. Triplett, wnmette, n1., assigner to Schweitzer & Conrad, Inc., Chicago, Ill., a corporation of Delaware Application May 13, 1933, Serial No. 670,884 10o Claims. (Omoo- 120) My invention relates to circuit interrupters.

While the specific embodiment which I shall illustrate and describe herein is a fuse adapted for the interruption of high tension current, it is to be understood that the invention is not to be limited to fuses, nor is the application of the invention limited to any particular voltage. Certain features of the invention are equally applicable to circuit breakers.

The chief problem in any fuse or circuit l breaker conducting current at considerable po-I Cgi tential is the prompt extinguishment of the arc which is formed upon separation of the contacts upon blowing of thefuse. The present invention provides a method of 'and means for facilitating the interruption of current flow by the deionization or quenching of the arc. I'he interruption of current flow in a circuit in which there is a rapid increase in the rate of current flow by reason of fault conditions presents a diiiicult problem, Whether the apparatus be a fuse or a switch or the like. The Schweitzer 8: Conrad fuse, which is well known on the market, has been widely used for automatic protection of circuits under such conditions. One form of such fuse now on the market is shown in the copending application of Nicholas J. Conrad, Serial No. 470,416, filed July 24, 1930.

One of the objects of the present invention is to improve the structure and mode, of operation of fuses of this character.

A further object of the invention is to provide a new mode 'of operation in the extinguishment of arcs in fusesswitches and the like, to the end of more rapid and certain operation, less violence of action, and confinement of the disturbance Within a completely closed housing.

The rapidity and certainty of operation reduce the release of energy both in the arc and in the connected system and facilitate the confinement of the disturbance to a closed container.

By confining the disturbance wholly within the housing it is possible to put the fuse in restricted spaces and to avoid the danger 'of flashing to ad jacent conducting structures. Also, the noise and contamination oi' the surrounding :atmosphere is avoided by confining the disturbance to the inside of the fuse housing.

Fuses of this general type, in operation, go through certain stages which occur with great rapidity. These stages include Vthe following:

1. The rise of current heats the fusible link to the point of fusion with the formation of an arc.

2. Relaxation of the holding power of the fuse permits the spring to begin the separation of the fuse terminals.

3. The heat of the arc causes evolution of metal vapors and expansion of the same. Also,

the heat of the arc acts upon the arc extinguishing material and evolves gases and vapors which are employed to deionize the arc or otherwise extinguish it.

4. Upon cessation of current iiow the separation of the terminals, cooperating with a suitable liquid dielectric, interposes such a barrier to reestablishment of the arc that restoration of the potential on the circuit will not restart the arc. This may be designated as the function of disconnection.

Heretofore it has been the practice to ll the fuse housing with arc extinguishing dielectric which serves the dual function of deionizing or otherwise extinguishing the arc and of serving as the insulating medium between the fuse terminals when the arc has been extinguished. and the stage of disconnection has been attained.'-

According to one phase of the present invention I provide two separate agencies, one' designed particularly for arc extinguishing purposes and another designed for a two-fold purpose-first, for the interposed insulation to' prevent restarting of the arc, and second, for extinguishing an arc which is not of great enough severity to release the first agency into activity.

The i'lrst agency may be so restrained or stabilized that it will not come into action, or effective action, except under the influence of an arc carrying relatively heavy current'low, whereas the second agency may respond to any size arc. In the preferred practice of the invention these two agencies are given opportunity, oneA after the other, to act in extinguishing the arc, and the second always interposes the insulating dielectric for the disconnecting function.

In the preferred embodiment the main arc extinguishing medium is water. This may be varied, as will be understood from the following. Also, the manner of holding the water or like medium may be varied. The arc extinguishing medium is exposed to the intense heat of the arc. Any compound which tends to become dissociated into fixed gases complicates the problem by the tendency to increase the fluid pressure within the fuse housing. If the dielectric material can be retained as a condensible vapor under the conditions of temperature and pressure which devices of this character encounter, the pressure within the device can be held down to such values as are safe for the container.

The arc extinguishing material should not serilously interfere with the insulating qualities of the liquid insulator, either before or after operation of the device.

The insulating liquid which I employ has arc extinguishing characteristics so that if the arc should persist to the exhaustion of the first arc extinguishing material, or without calling the first material into play, the insulating liquid 5 action of great effectiveness.

serves as a secondary arc extinguishing material.

A further feature of improvement, according to the present invention, resides in. the means and method of controlling and ez-rtinguishing the arc after blowing of the fuse. ccording to the present invention the fuse is irntially conned in a chamber disposed' inside the fuse housing. The upper end wall of the chamber, in the preferred form, is a fuse terminai formed somewhat like a valve. The outlet opening through which the arc is extended upon operation of the device is preferably a restricted Venturi-line opening. The rst terminal moves in a guided manner away from the said opening, retaining the arc in substantially central position with respect to the said restricted opening. Optionally, said rst terminal may be initially xed in line with the outlet ofthe arcing chamber with an annular opening around it providing communication between the space in which the arc is held and the condensing and recombining chamber. The arc extinguishing material which is evolved or released by the arc is driven violently through said opening, thereby providing an arc extinguishing The arcing chamber preferably is otherwise substantially closed. The rod-like cooperating terminal is meanwhile withdrawn towards the bath of insulating liquid, which also has arc extinguishing characteristics. The arc extinguishing medium expelled from the arcing chamber is discharged along the length of the arc and around the rst terminal into the condensing chamber where a cooling or chilling of the gases and vapors occurs, thereby holding down the pressure, which would otherwise tend to be excessive. This receiving chamber performs two functions, rst, recombination of the ions and second, chilling and condensing of the gases and vapors.

For arcs of diierent rates of current increase the device operates differently. The arcing chamber containing the stabilized or xed water acts promptly and effectively to release the water and extinguish the arc upon rapid rise of current, which indicates a fault of low resistance. But if the rate of rise of current is small, indicating a fault of high resistance, or merely overload, the arc may not release the water. In that event the arc is drawn through the chamber which contains the xed water and is extended into the liquid below the arcing chamber, and there evolving a vapor and gas which extinguishes the arc.

I consider it to be broadly new to employ two media within the fuse, one for the evolution o one form of' arc extinguishing material and the other for the evolution of another form of aro extinguishing material, so arranged that the rst which is brought into action by one set of conditions is backed up by the other, which is elective under all or diierent conditions. The rst may be a solid and the second a liquid, or vice versa, or they may both be solids or both liquids.

The structure may be viewed as providing two bores through which the movable contact travels. The rst is particularly effective for'heavy current ow in the arc, and the second particularly eiective for light current flow in the arc.

cooling capacity of the condenser or cooling chamber, so that for the maximum current ow for which the devicel is designed the pressure in the arcing chamber and reccmbining chamber or connected spaces will not become excessive. f the current -in the arc should exceed the rated maximum value, then the vent is removed and the pressure rcducing effect becomes unimportant but the metal grids or plates serve to prevent the ejection of fire at the vent.

Numerous other improvements in structure and inode of operation will be apparent from the following detailed specication.

Now in order to acquaint those skilled in the art with the manner of constructing and operating a device embodying my invention I shall describe, in conjunction with the accompanying drawings, a specific embodiment of my invention.

1n the drawings:

Figure 1 is a longitudinal vertical section through theY upper end of a fuse embodying my invention;

Figure 2 is a similar sectional view through the lower end of the same fuse;

Figure 3 is a transverse cross section taken on the line 3-3 of Figure 1;

Figure 4 is a longitudinal vertical section of a modication on an enlarged scale, showing the dierent disposition of the liquid containing vessels in the arcing chamber;

Figure 5 is a transverse sectional view taken on the line 5-5 of Figure 4;

Figure 6 is a longitudinal vertical section through the upper end of a modication;

Figure 7 is a longitudinal vertical section through the lower end of the same;

Figure 8 is a longitudinal vertical' section through the upper end of another modification;

E'gure 9 is a fragmentary longitudinal vertical section of a modification showing a fixed arcing tip; and

Figure 10 is a similar fragmentary longitudinal vertical section showing the lower arcing tip as detachable from thespring retracted plunger.

Referring rst to the device shown in Figures l, 2 and 3, there are three chief functional divisions of the fuse, namely, the arcing chamber i, the recombining and condensing chamber 2, and the disconnecting chamber 3. The active operation of confining and extinguishing the arc occurs chiefly in the arcing chamber l. The gaseous or vaporized arc extinguishing medium evolved in the chamber i is driven into and expanded by releasefrom the arcing chamber 8 into the condensing chamber 2, where a mass of nely divided metal is freely accessible to the gases and vapors for the purpose of cooling and condensing the same in order to prevent any excessive rise of pressure. Disconnecting chamber 3 contains a body of insulating dielectric medium which may be suitable halogen derivatives or hydrocarbons heretofore employed in fuses of this character, or the like, serving as an insulating medium between the movable fuse terminal and the movablefuse terminal may retreat. -w

The structure in detail is as follows:

The glass sleeve 4 has mounted upon the lower.

end thereof a metallic ferrule 5 which forms an external circuit terminal. This ferrule 5 is secured by a suitable sealing alloy 6 to the lower end of the glass sleeve 4. 'Ihe ferrule 5 has an extension I within which there is provided a.

socket 8 for receiving the threaded stud 9 of the spring head i0. The spring head It) has grooves for receiving the lower turns or coils of the coil spring I2 and it also has a socket I3 into which is secured the lower end of the flexible conductor I4. This form of spring mounting and flexible 5 lead connection is of a type similar to prior constructions with the exception that herein the metallic portion is extended, requiring a less length of glass sleeve 4.-

At the upper end of the glass sleeve 4 there is secured the ferrule I5 by means oi the sealing alloy 5. The ferrules 5 and I5 are preferably formed of brass. The ferrule I5 has a narrow flange I5 extending inwardly and being threaded to receive the threaded ring I1 having an inwardly extending ilange I8 provided with a conical tapered valve and contact seat I9 upon which rests a valve-like member' 20 which forms a fuse terminal at the upper end of the arcing chamber I. This valve member may be sealed 20 to its seat by sealing compoundwhich will not be attacked by the liquid below it. This 1s optional within my invention. This disc-like valve member 20 has an arcing tip 22 to which is secured the upper end of the fusible conductor 23 25 and also the upper end of the high tensile strength wire 24 generally termed the strain wire. The

arcing tip or terminal 22 is formed in the shape of a screw threaded into the lower surface of the disc member 20. The imember 20 has a shank 25 to' which is connected a guiding stem 26. 'I'he guiding stem 26 is cylindrical in shape and extends inside of the tubular metallic guiding sleeve 21, threaded at its upper end into the metallic spider member 28, said spider member being in turn supported within the metal cylinder 29 which forms or denes the side walls of the condensing chamber 2. The metallic cylinder 29 is threaded at its lower end upon an outwardlyl extending flange 3l! which is integral with the ferrule I5. The upper end of the metal cylinder 29 is closed by the threaded plug 32 which has a. central opening 33 covered by a cap 34 suitably cemented in place and releasable upon excess pressure 1n the chamber 2 to vent the device to atmosphere. 'Ihe central tubular guide 21 in the condenser chamber 2 supports a series of sheet metal stampings 35; These stampings are preferably made of copper provided with transverse central openings for assembly upon the metal sleeve 21 and perforated throughout their area to provide relatively free access of the vapors and gases to secure a large condensing surface. The stampings 35 are separated by washers or spacers 35 and are clamped together by the spacing ring 31 at the upper end and the threaded nut 28 at the lower end of the tube 21. Th`e stem 25 of the valve-like member 2li is slotted or biiurcated as indicated at 39 and the legs or bifurcations are sprung outwardly so as to give a frictional -engagement of the stem 25 with the inside of the guiding sleeve 21. This is for the purpose of keeping the valve centered and in raised position after the action of expelling the same from its seat I9. Also it maintains a conductive connection between member 20 and sleeve 21 which is connected to ferrule I5 so that the arc current will ilow through the same. Instead of a sliding contact a flexible connection such as a braided conductor or pigtail might be used, as shown at detail 2l in Figure 8.

The arcing chamber is formed within the tube 40 which is formed by wrapping of paper impregnated with a synthetic resin or phenol condensaton product into a tube and then baking or otherwise treating to set the same. At its upper end the tube 40 is provided with a ringlike annulus of insulation 42 which forms an orifice 43. This ring 42 is provided with a iiange 44 which is set in a corresponding counterbore in the upper end of the tube 40. The upper ends of the ring 42 and of the sleeve 60 engage the bottom surface of the ange I8 of the ring Il'. .A split ring 45, lying in grooves formed in the tube 40 at its upper end, and the adjacent part of the metal sleeve or ring I1, locks the parts together. The ring 42 ls undercut at its lower end to receive the upper reduced ends oi a series of glass vials 46 which contain water. The water may have a suitable amount of anti-freeze material, such as alcohol, glycerine, or preferably ammonium hydroxide in the amount of about 3 per cent, or the like, to prevent cracking of the glass in case the device is subjected to low temperature. The vials may contain arc ex- /tinguishing material in liquid, gas, granular or solid, which will, under the influence of the arc. be released from the container. The vials may be made of any suitable material which will protect the contents until they are to be used and will definitely release them when they are needed. One advantage o-f this construction is the ability to provide a material or materials which should not be exposed or mingled with the other material or materials until the arc is formed.

At the lower end these glass vials are similarly reduced in diameter in order to rest back of a circumferential flange 41 formed on a pluglike member which is perforated to permit the rod-like terminal 49 to be inserted into the arcing chamber I therethrough. The plug 48 is held in place by a split ring 50 set in a groove in the inner surface of the tube 40 and held between a screw ring 52 and a shoulder 53 formed on the outer surface of the plug or ring 48. The hole or bore of the plug 49 is provided with a series of packing grooves 54 forming a labyrinth packing to conne within the chamber I the contents thereof upon blowing of the fuse. The lower end of the fuse 23 and strain wire 24 are connected through an arcing tip 55 secured upon the upper end of the rod-like terminal 49. The lower end of the rod-like terminal 49 is provided with an enlarged head 56 which is threaded into the socket formed in the connecting member 5l which has at its opposite end a socket 59 for receiving the upper end oi the flexible conductor I4. The upper spring head 59, which is connected to the upper end of the spring I2, is coupled to the connecting member 51 so that the spring I2, which is under tension. tends at all times to ,withdraw the rod-like terminal member 49 from its position in the chamber I and to plunge the same beneath the surface of the arc extinguishing liquid 60, which liquid normally lies at approximately the level shown in Figure 1.

The arcing tip 55 may be enlarged as shown in Figure 8 to such a diameter that it will close oi the`opening through the plug 53 and prevent communication between the arcing chamber I and the spring chamber 3. In that event, the entire extinguishing action is carried on within the chamber I. Such closure of the lower end of the chamber I prevents the escape of the are extinguishing material within the chamber I into the insulating liquid 50. To assist in sealing the lower end of the arcing chamber I, a gasket 5I, as of vegetable parchment, shown in Figure 8, may be employed between the enlarged head 55 and the plug 53. The tip 55, being so enlarged to close the opening 41, may be releasable from the stem d. It may be releasably held by the fusible wires 23 and 2li, preferably the latter. I, have shown such a releasable tip in Figure 10. In this construction the tip 55 is 5 secured in the upper end of a head member Illt secured to the upper end of the spring retracted stem [59 by a releasable clutch. The head TI has an annular shoulder I3 and a reduced shank portion i9 surrounded by a small compression spring A sliding clutch member 82 guided on the shank 'I9 and pressed downwardly by the compression spring 3E) normally restrains the clutch ballsv 83 which are carried in a transverse bore formed in the shank 'I9 and project into a groove 8d formed in the upper reduced end 85 of the stem t9, which reduced end 85 projects into a bore formed in the lower end of the shank 19. The clutch member 82 is a ring having three different diameters, the upper diameter 20 being such as to provide a sliding t on the shank lil. The next lower diameter is such as to restrain the clutch balls 33 locked in the groove 8d. The lower and largest diameter, indicated at 86, when brought in register with the 25 clutch balls 83, wili permit them to expand outwardly under the pull of the spring I2 which is connected to the movable stem di). The lower ring 53 has a guiding bore for the movable stem 49 and above that has a conical tapered seat for 3o receiving the outer conical tapered surface 88 of the clutch member 82. The release is eiected as follows. When the fusible link melts and the l lower movable stem Q9, with connected parts, descends, the clutch member d2 engages the seat 35 81 but the pull of the spring I2 overcomes the resistance of the small spring Sil and pulls the l shank 79 downwardlyv and carries the clutch balls 83 into register with the enlarged diameter 88 of the clutch member S2, thereby releasing the shank 85 from thememher ll. Vlfith the tip released the stem t9 is then drawn down into the liquid for the disconnection function.

The disconnected parts Il and` 82 then serve like a check valve to prevent ow from the chamber direction. A The annular restriction 3 has a novel utility. It chokes the arc. My study of arcs leads me to the conclusion that the free cross sectional area 50 of an arc is proportional tc the current now which the arc carries. device it is true that the arc starts incross section with the fuse wire and tends to expand outwardly to a `cross-section corresponding to the current lflow while the annular restriction remains stationary. The arc might be considered as being formed and as standing still, and the restriction thereafter closing in upon it and choking it. So far as the relative motion between the two is concerned, the action is broadly the same within my invention. By thus limiting or choking at one point the cross sectional area of the arc, there is a tendency to reduce the current carrying capacity at that point. This restriction would tend, however, quickly to be destroyed by the heat of the are if the arc were permitted to act directly upon the same.

I preserve the constriction against injury and, in fact, increase the constriction by the discharge of a ow of fluid in annular form about the arc. This ow of uid about the arc performs several useful functions. First, it is a continually renewed shield between the body of the arc and the restriction 43, preserving the latter against ,I into chamber 3 but permit ow in the other n the operation of my l breakdown due to the heat of the arc. Next,

, forcing the arc extinguishing uid through the restriction and about the arc further reduces the eiective opening or increases the constriction of the arc. Also, the motion of the uid is such as to carry ionized gases, metallic vapors, etc., out of the region of the arc, by discharging the same in an annular stream past the upper terminal 22. The expansion of the gases beyond the restricted portion tends to cool the same, or at least to hold the temperature down to a value which is cold, as compared to the arc.

The operation of the device is as follows:

The arcing chamber is intended to conne the initial action of blowing of the fuse. It is made of suiiicient strength to withstand the pressures which may be encountered under extreme conditions, thereby preserving the glass sleeve d from the heat and shock of the blowing of the fuse. The arcing chamber I is closed of either tight or substantially tight. The tension of the spring I2 pulling through the strain wire 2t upon the valvelike member holds it upon its tapered seat I9. The valve'E may retain the arc extinguishing liquid within the lower part of the housing. Since the ring member I'I and ferrule flange I6 are fastened together, the arc extinguishing and insulating liquid Sl) is prevented from entering the condensing chamber 2 during shipment of the device. Exclusion is optional. kept below the valve the condenser need not be as tight as if the liquid is admitted. Where sealing is desired a thin cement or viscous compound may be employed to seal the valve 2@ to its seat I9.

Assuming that the parts are in the position shown in Figures 1 and 2 and that through the occurrence of a severe fault upon the connected system the rise of current proceeds Yat a rate which indicates that automatic operation of the device should occur, the fuse 23, which is preferably made of silver, and the strain wire 2li, which is preferably made of a high tensile strength material such as a nickel-chromium-iron alloy, thereupon are fused and an arc tends to be established. The current flow, normally, is between the ferrules 5 and l5, as follows, namely, ferrule E through the exible conductor Id to the fuse terminal 159, through the fuse and strain Wire to the arcing tip 22 and the valve-like member 20. The shortest path from the member 28 to the fer- .rule is through the flange I8 of the ring or sleeve II and thence directly to the ferrule I5. An alternative and longer path is through the stem 26, sleeve 2l, spider 28, cylinder 29 and through the flange 30 to the ferrule I5.

As soon as the current ilow has melted the fuse f an arc is established between the fuse tips 22 and 55. The holding power of the fuse upon the spring I2 is gone and the rodlike terminal 49 is released. The melting of the fuse and strain wire results in an immediate rise in pressure in the explosion chamber due to the expansion of the gas and to the formation of metal vapor, with the result that the valvelike member 20, which is free of the spring I2, is blown upward, being guided by its stem 26 in the sleeve 2l' so that the tip 22 is moved accurately in alignment with the orifice i3 in the ring d2.

The orice at the upper end of the arcing chamber has its maximum tendency to restrict the 'ow of gases into the condenser when the current flow is maximum. The outow of arc extinguishing uid through the orifice through which the arc is drawn is hindered by the size of the arc. The arc tends to increase in diameter with the current iiow which is carried. The cross section isA thus automatically adjusted, so that the current density remains approximately the same throughout the current wave. When the current is at zero, due to change in direction at each half cycle, the arc offers the least impediment to ilow of vapor from the arcing chamber and the ow of vapor at this time is most effective in preventing restriking of the are following zero current, since the aforesaid flow of vapor tends to sweep out of a definite part of the arc path conductive ionized gases, vapors, etc. 'I'he provision of this orifice results in accumulation of pressure in the arcing chamber during the growth of the arc and an increasing release of pressure as the arc decreases in cross section. Flow of vapor through the orifice is relatively least when the current is maximum and relatively greatest when current is zero. All current variations thus described are the sinusoidal variations of the current wave. At the same time, the heat of the arc either directly cracks the glass of the vials 46 or causes such rapid generation of F pressure within the glass vials that the water which is contained within them is released into the arc and is vaporized, causing pressure to rise within the arcing chamber I and to be driven violently through the. orifice 43.

As soon as the valvelike memberZ@ leaves its seat I9 on the ring I1 the path. of current flow is from the arcing tip 55 through the arc to the arcing tip 22, then through the stem 26, sleeve 21, spider 28 and outer cylinder 23 of the condensing chamber 2. The tip 22, in conjunction with the tip 55, holds the arc accurately in axial alignment with the orifice 43, with the result that the violent flow of arc extinguishing medium (in this case water or steam) through the said orifice tends to exert a strong arc extinguishing action which quickly puts out the arc. A part of the arc extinguishingl action is the result of the cooling of the member 20 and the adjacent part of the arc by the rapid expansion of the gas and Vapor as it issues from the nozzle opening 43 under the disc-like member 20.

The mass of condensing plates 35 serves to condense the water vapor and to hold down the pressure which would otherwise be caused. Water is an eicient arc extinguishing medium. It does not appear to be readily dissociated by the heat of the arc, but merely vaporized. It can readily be condensed, and thereby save the high increases in pressure which would result if the arc extinguishing medium were dissociated into fixed gases. The amount of arc extinguishing material disposed in the arc extinguishing chamber is limited, but it is used efliciently. By limiting the amount of arc extinguishing gas that is evolved upon a rated maximum current ow, the cooling and condensing chamber and its cooling plates may be so proportioned as to keep the pressure from increasing beyond a safe value. If, however, the rated maximum current is exceeded, and the pressure rises above the predetermined value deemed safe, the cap 34 is blown off. 'Ihis vents the cooling and condensing chamber to atmosphere. Hence the pressure reducing effect of the plates 35 is no longer important. But they new take on a new function, namely, that of preventing the ejection of burning gases by the chilling eiect which they exert upon the gases streaming out of the arcing chamber to the vent opening 33. I

I refer, in the present specification and claims,

to a gaseous medium, intending thereby to include vapors, gases, and the like.

If the arc should persist during any appreciable movement of the rodlike terminal 49, the lengthening of the arc on the lower side of the orifice 43 will merely bring more of the water, or other arc extinguishing medium, into action upon the arc and thereby will tend to increase the extinguishing action.

By the above structure the arc is embraced by the annular ring 42 and it is then lengthened on each side of the said ring. A pressure is generated on one side of the ring and discharged through the ring to the other side, thereby creatlng a strong arc extinguishing action. The rodlike terminal 45 is not hampered by a liquid director, and it descends rapidly. It is guided centrally in the head 48. Upon leaving the arcing chamber l the rod-like terminal 49 is submerged within the liquid 6G and, if necessary, the liquid 66 could continue to furnish an arc extinguishing medium after the medium inthe arcing chamber were exthausted. Sometimes the fuse blows under conditions of fault or load which limit the current ilow in the arc to a relatively low value. The arc may not be severe enough to cause release in the glass vials. Th-en the arc is drawn down into the liquid 60 which supplies the gaseous medium that extinguishes the arc. At all events, the submergence of the terminal 49 in the liquid 60 interposes a. liquid dielectric between the said terminals and any conductive parts above the same, so that upon reestablishment of the potential of the circuit the arc will not be reformed.

Such an arc extinguishing liquid is preferably employed as will not be injured by .contact of water therewith. A suiiiciently heavy insulating liquid may be employed that water will iioat upon the surface thereof.

While I have shown in Figures 1 to 3 the employment of vertical vials or containers 4G for the arc extinguishing medium it is to be understood that other arrangements of the same may be provided. For example, in Figures 4 and 5, I have shown circularly disposed water containing units. Here toroidal hollow rings of glass fllled with water as shown at 62-63 are disposed within the insulating tube 40. I do not intend to limit the filling of the containers such as 40 and 62 to liquid, as the arc extinguishing material may be any of those now known and which are suitable for this use. The iilling may be liquid, gas or solid, in either block, granular, or powdered form.

The rings 62-63 are lled and sealed ofi as indicated at 64 and spacing washers or rings suitably recessed to receive the sealed off portions 64-84 are provid as indicated at 65. In this construction the release of more water than is needed for the particular operation of extinguishing the arc is prevented. That is to say, the arc will not break down the water containers below the level of the arc, with the result that there is no more water released than is necessary, therefore the water tends to be progressively released.

In Figures 6 and 7, I have illustrated a modification in which the same arc extinguishing liquid is employed in both the arcing chamber I and in the disconnecting chamber 3. If desired, a layerl of some other liquid may be superposed upon the liquid beneath it, so that the advantage of the facility and ease of condensing the rst liquid may be employed. In this construction the arcing chamber l is defined by the sleeve dil, as before. The upper end or" the sleeve or tube it is provided with the ring 42 for defining the orifice Q3. The valve-like member 2Q seats upon 5 the conical tapered seat le formed on a ring member 6l. The ring member 5l has an internally extending flange overhanging the upper end of the ring t2. The tube Q@ is threaded into the inside periphery of the metal ring 6i and 10 it engages the lower side of the ring of insulation d2 which denes the orifice 33. The metal ring di is externally threaded to cooperate with the threaded iiange it of the ferrule i5.

Provision is made for permitting the return of any liquidv which might escape past the valve 2G into the condensing chamber 2 during shipment or the like, this arrangement consisting of a peripheral groove t@ cut in the ring di, and one or more holes 69 drilled from the top side to the groove 68 and one or more holes lil drilled from the bottom side to the groove et, to allow for the ow equalization of pressure between the condensing chamber 2 and the space between the glass Sleeve l and the insulating tube 30.

This space communicates with the disconnecting chamber 3 and also communicates through the aperture plug le with the interior of the Y,arcing chamber l. A hole 'El through the valve member 2@ may be provided for the same purpose.

In the present construction the lower rod-like terminal i9 which carries the arcing tip 55 to which the lower end of the fuse 23 and strain wire 2d are attached is adapted to be plunged freely downwardly in the liquid with which the device is filled until the said head 55, which forms the arcing tip, is withdrawn from the chamber i, whereupon the arcing tip or head 55 engages with the sleeve l2 and pulls the liquid director 73, which is attached to the sleeve 'l2 as by means of the spring clip ld, downwardly with it, and if the arc should persist beyond the arcing chamber l such lost motion connec tion of the arcing tip with the liquid director causes the liquid to be sprayed upon the arcing tip to extinguish the arc. The liquid director also guides the tip i9 centrally of sleeve d.

The operation of this embodiment is similar to the operation of that shown in Figures 1 to 5, inclusive. However, in the present case the arcing chamber l does not contain the glass vials -for separately containing the liquid, the liquid in this case-standing up free Within the chamber l to the desired level. Upon blowing of the fuse thejvalve-like member 2G, with its arcing tip 22, is blown upwardly and the rod-like terminal $9 begins to descend. The arc extinguishing liquid 60 is vaporized by the heat of the arc and high pressure is generated in the chamber l which is expelled through the orifice i3 against valve 2li. The tips 22 and 55 hold the arc centralized where it is most vulnerable to attack by the iiuid rapidly flowing through the orifice $3. Thus the liquid cools the lower terminal and as it is expelled and expanded it also acts upon the valve 2li. I believe it is'broadly new to have the liquid thus act upon both terminals of the arc.

It is to be observed that if the arc should attempt to persist across the gap formed between the disc 2U vand the seat i9, the transverse iiow l path extends through the stem 26, the guiding Qir-Ql l ltube 2i, spider 23, and outside sleeve 29 of the chamber 2. The shift from one conductive path to the other is secured by the explosive eiiect of the arc lifting the disc 2b away from its seat. Any tendency forthe current ow to persist as between valve 2li and its seat le is overcome by the blast of arc extinguishing material through that space.`

It is to be understood that I do not wish to be limited to the specific arrangement which I have .shown for holding in readiness within the chamber l a suitable arc extinguishing medium. For example, I may employ a solid material such as boric acid or silicio acid in solid form within the tube lil in a manner similar to that in which the glass water containers are mounted, or as a single continuous sleeve of the material. There are numerous materials which will evolve Water under heat. It is also to be understood that I do not limit the invention to the use of a material which will evolve water. i may, for example, employ a material which will evolve a vapor or a gas capable of extinguishing the arc or assisting in doing so.

In Figure 9, I have illustrated the use of a solid arc extinguishing material 39 formed as a sleeve adapted to t within the impregnated ber sleeve il@ and held in place between the upper choking ring d2 and the lower ring 53, which is not shown in Figure 9. By reference to Figure 8 the relation oi these two rings may readily be determined. 'Where the solid arc extinguishing material is employed, as shown in Figure 9, the liquid level for the disconnecting liquid preferably lies immediately at or below the lower ring 53, through which the movable terminal i9 passes. The arcing tip 55 may be enlarged, as in Figure 8, to shut off the chamber l from the space below the same when the movable plunger or rodlike terminal i9 is pulled down by the spring. As heretofore explained, the solid arc extinguishing material may be disposed within the glass vials it or be placed uncovered in annular or sleeve form, as shown at B9 in Figure 9, to form a lining for the arcing chamber i. l

These vials, such as 15d, permit the employment of gas, liquid, powder or any other form of material desired, or combination of them, without contamination of' the insulating liquid Eil, or of the contents of other vials. Materials which would be quite unsuitable otherwise on account of corrosiveness or deterioration of the metallic parts or of the insulation, may thus be employed. If desired, the expulsion of the contents of these vials into the condensing chamber 2 may be made permanent by permitting the valve `member 2li to drop back to its seat after the explosion. Forthat purpose a exible pig tail or conductor may be employed in lieu of the sliding connection shown. lSuch a construction is shown in Figure 8. Also, instead of using aterials which will unite when released by the arc to produce a strong arc extinguishing eect. Such materials may be employed as could not satisfactorily be combined in advance.

Also, the vials'such as 4E o'r 62-83 in the arcing chamber l, may have different materials -in them which are released and combined within the single chamber upon blowing of the fuse.

I also contemplate including in a portion of the l capsules or vials a material which will act as a. preservative of the dielectric bath 60 after blowing of the fuse, in order to counteract unfavorable eiectsrom the materials released from the other capsules or vials.

I may extend the length of the upper arcing tip 22 so far that when the valve 20 rises to its upper position the tip 22 is still within the chamber` I. The valve 22 may be suitably held closed by a known shear pin 2l or the like, as shown in Fig. 8 to compel a certain rise of pressure within chamber I. When the tip 22 definitely remains in chamber I the choking ring is preferably enlarged or removed.

In Figure 8, I have illustrated an elongated arcing tip 90 to take the place of the shorter arcing tip 22 shown in Figure 1, this tip being of such length that when the valve 20 and its connected stern 26 with flexible lead 2| are driven to the uppermost position, the lower end of the tip SII will still remain substantially within the arcing chamber I.- By suitably adjusting the length of the arcing tip such as 90, any desired linal position may be obtained.

In the embodiment shown in Figure 9 the arcing tip S2 is fixed with respect to the arcing chamber I. The arcing tip has a threaded shank 93 which threads into the lower end of the tube or sleeve 21 and it has a polygonal flange 94 which may rest against the lower end of the condenser plate 35 to hold the condenser plate securely in position. Obviously, this form of fixed arcing tip may be varied in length. The fixed arcing tip may be substituted, in any of the previous embodiments, for removable arcing tips, if desired. As shown in Figure 9, the end of the arcing tip is beyond the constriction produced by the ring 42 so that the arc extinguishing medium driven out of the chamber I by the effect of the arc upon the solid arc extinguishing material 89, impinges directly upon the end of the tip 92 Where the arc would tend to maintain it-A self. In Figure Ill the arcing tip 92 is fixed, and projects through the constriction produced by the ring 42. The embodiment shown in Figure withdrawn' from the arcing chamber I, there will be arc extinguishing material playing upon each end of the arc through the centralizing orifices.

The mass of condensing iins 35 is useful in controlling the temperature of not only vapors but also of gases, to limit the rise of pressure which might occur within the device.

Where I employ herein the terms upper and lower in describing the relative positions of the parts, this is to be understood as being descriptivev and not limiting. Also, in/su/ch parts of the specification and claims wherein the number 20 is referred to as a disc, or disc-like, it is to be understood that this is descriptive, rather than limiting, inasmuch as the valve-like member 20 might be considered as a plug, as well as a disc. It functions merely to restrict -to the desired degree the outlet at the upper end of the arcing chamber I-and to form a conductive path fromv the arcin'g tip 22 primarily through its periphery, primarily through its seat when seated, and secondarily through its guiding stem when raised from its seat.

A wick-like holder for arc extinguishing liquid such as disclosed in my co-pending application, Serial No. 663,955 filed May 8, 1933, may be employed within the arcing chamber.

The member 20 need not be a complete disc, nor form a tight closure. It is preferably movable, but I believe it is broadly new to have the upper terminal central and to have the arc extinguishing material surround the arc and the upper terminal. The arcing tip 22 might be maintained in fixed central position beyond opening 43 Without the valve disc 20 and still serve a highly useful function. Such a form of tip is shown at92 in Figure 9.

I do not intend to be limited to the details shown, and described. I intend to cover ali devices coming Within the spirit and scope of the invention as dened by the appended claims.

I claim:

l. In combination, a tubular fuse housing comprising a sleeve of insulation having metallic ferrules at its ends, said ferrules forming external circuit terminals, a tubular fuse chamber disposed within said housing adjacent one end thereof, said chamber having an opening adjacent one end, a movable rodlike fuse terminal projecting into said chamber through said opening, said rodlike terminal being connected to one of said ferrules, a movable disclike fuse terminal obstructing the other end of the chamber, a seat for said latter terminal, said seat being connected to said other ferrule, a fusible link in the chamber connecting said terminals, and a shunt connection between said disclike terminal and said one ferrule independently of said seat.

2. In combination, a tubular fuse housing comprising a sleeve of insulation having metallic ferrules at its ends, said ferrules forming external circuit terminals, a. tubular fuse chamber disu posed within said housing adjacent one end thereof, said chamber having an opening adjacent one end, a movable rodlike fuse terminal projecting into said chamber through said opening, said rodlike terminal being connected to one of said ferrules, a movable disclike fuse terminal obstructing the other end of the chamber, said disclike terminal being permanently connected to the other of said ferrules, a. fusible link inthe chamber connecting said terminals, and a spring in the housing for retracting said rodlike terminal.

3. In combination, a tubular fuse housing comprising a sleeve of insulation having metallic ferrules at its ends, said ferrules forming external circuit terminals, a tubular fuse chamber disposed within said housing adjacent one end thereof, said chamber having an opening adjacent one end, a movable rcdlike fuse terminal projecting into said chamber through said opening, said rodlike terminal being connected to one of said ferrules, a disclike fuse terminal obstructing the other end of the chamber, said disclike terminal being movable away from the end of the chamber but being permanently connected to the other of said ferrules, means for guiding said disclike terminal, a fusible link in the chamber connecting said terminals, and a charge of arc extinguishing material disposed within said chamber.

4. In combination, a tubular fuse housing comprising a. sleeve of insulation having metallic ferrules at its ends, said ferrules forming external circuit terminals, a stationary tubular fuse chamber disposed Within said housing adjacent one end thereof, said chamber having a restricted openingr adjacent one end, a movable rodlike fuse terminal projecting into said chamber through said restricted opening, said rodlike terminal being connected to one of said .ferrules, a disclike fuse terminal closing oiI the other end of the chamber, said disclike terminal being connected to the other of said ferrules, means to limit the motion of said disclike terminal, a fusible link in the chamber connecting said terminals, and a charge of arc extinguishing material disposed within said chamber.

5. In combination, a tubular fuse housing comprising a sleeve of insulation having metallic ferrules at its ends, said ferrules forming external circuit terminals, a tubular fuse chamber xedly disposed within said housing adjacent one end thereof, said chamber having an opening adjacent one end, a movable rodlike fuse terminal projecting into said chamber through said opening and being movable relative to said chamber, said rodlike terminal being connected to one oi said ferrules, a fuse terminal disposed at the other end of the chamber, said latter terminal being permanently connected to the other of said ferrules and held in alignment substantially axially with respect to said chamber, a fusible link in the chamber connecting said terminals, said chamber having a portion of its bore adjacent said latter terminal constricted to form an orice through which extends the arc formed upon blowing of the fuse, and a charge of arc extinguishing material in said chamber.

6. In combination, a tubular fuse housing com prising a sleeve of insulation having metallic ierrules at its ends, said ferrules forming external circuit terminals, a tubular fuse chamber disposed within said housing adjacent one end thereof, said chamber having a restricted opening adjacent one end, a movable rodlike fuse terminal projecting into said chamber through said restricted opening, said rodlike terminal being connected to one of said ferrules, a disclike fuse terminal closing off the other end of the chamber, said disclike terminal being connected to the other of said ferrules and being movable by pressure Within the chamber, a fusible link in the chamber connecting said terminals, a spring in the housing for retracting said rodlike terminal, and means for holding the disclike member away from the end of the chamber after the same is expelled by blowing of the link. "1. In combination, a tubular fuse housing com- Drising a sleeve of insulation having metallic ferrules at its ends, said ferrules forming external ing, said rodlike terminal being connected to one of said ferrules, a disclike fuse terminal covering the other end of the chamber, said disclike terminal being connected to the other of said ferrules, a fusible link in the chamber connecting said terminals, a charge of arc extinguishing material disposed within said chamber, and a condensing chamber adjacent said other end of the fuse chamberfor receiving and condensing the arc extinguishing material ejected from the fuse chamber.

8. In a fuse a tubular fuse chamber having an outlet at one end thereof, a fusible link, ter- Vminals for the link, a sealed frangible container in said chamber in position to be broken upon blowing of the link, but out of contact with the link, there being a free longitudinal passageway about said fuse leading to said outlet, said container being charged'with arc extinguishing material. 5

9. In a fuse a fuse chamber having an outlet at one end thereof, a fuse in said fuse chamber, a sealed frangible container in said chamber in position to be broken upon blowing of the fuse, there being a free longitudinal passageway about l0 said fuse leading to said outlet, said container being charged with arc extinguishing material and extending longitudinally along the fuse, and out of engagement therewith.

l0. In a fuse a fuse chamber, a fuse in said l5 fuse chamber, and a sealed frangible container in said chamber in position to be broken upon blowing of the fuse, said container. being charged with arc extinguishing material and being disposed circumferentially about the fuse, the fuse 20v being external to said container. f

ll. In a device o1' the class described, a tubular fuse chamber, a fuse in said chamber, and a charge of arc extinguishing material comprising water disposed in said chamber about said fuse, 25 and out of contact therewith one end of said chamber having an opening through which Said Water is expelled upon blowing of the fuse there being a longitudinal passageway about the fuse leading to said opening. 30

l2. In a device of the classdescribed, a tubular fuse chamber having an outlet at one end, a fuse in said chamber, terminals for said fuse, a surrounding mass of material enclosed in a wrapper and adapted to release water under the action 35 of the arc formed upon blowing of the fuse, said mass being out of contact with said fuse and means in said chamber independent oi'` said fuse terminals for engaging and holding said wrapper there being a longitudinal passageway about said 40 fuse leading to said outlet.

13. In combination, an insulating sleeve, a closed ferrule on the lower end of the sleeve, an open ferrule on the upper end of the sleeve, a condensing chamber forming a continuation of 45 the upper ferrule, said upper ferrule having an inwardly extending flange abovev the end of the sleeve, an insulating tube disposed within the upper end of the sleeve and lying below the flange, a disclike terminal resting on the ange, 5o a rodlike terminal extending through the lower end of the tube, said latter terminal being electrically connected to the lower terminal, a spring for moving the rodlike terminal downwardly in the tube, and a fusible link connecting the two 55 terminals.

le. In combination, an insulating sleeve, a closed ferrule on the lower end of the sleeve, an open ferrule on the upper end of the sleeve, a condensing chamber forming a continuation of 6o the upper ferrule, said upper ferrule having an inwardly extending ange above the end of the sleeve, an insulating tube disposed within the upper end of the sleeve and lying below the flange,

a movable disclike terminal resting on the ange, 65 a rodlike terminal extending through the lower end of the tube, said latter terminal being electcally connected to the lower ferrule, a spring for movingthe rodlike terminal downwardly in the tube, a fusible link connecting the two ter- 7o minals, and guiding means in the condensing` chamber for controlling the movement of the disclike terminal.

15. In combination, an insulating sleeve, a closed ferrule on the lower end of the sleeve, an 75 open ferrule on the upper end of the sleeve, a condensing chamber forming a continuation of the upper ferrule, said upper ferrule having an inwardly extending flange above the end of the sleeve, an insulating tube disposed within the upper end of the sleeve and lying below the an'ge, Va disclike terminal resting on the flange, a rodlike terminal extending through the lower end of the tube, said latter terminal being electrically connected to the lower ferrule, a spring for inoving the rodlike terminal downwardly'in the tube, a fusible link connecting the two terminals, and an annular ring at the upper end of the tube forming a constricted outlet for the tube. A

16. In combination, an insulating sleeve, a closed ferrule on the lower end of the sleeve, an open ferrule on the upper end of the sleeve, a condensing chamber forming a continuation of the upper ferrule, said upper ferrule having an 20 inwardly extending ilange above the end of the sleeve, an insulating tube disposed within the upper end of the sleeve and lying below the flange, a disclike terminal resting on the ilange, a rodlike terminal extending through the lower 25 end of the tube, said latter terminal being electrically connected to the lower terminal, a spring for moving the rodlike terminal downwardly in the tube, and a fusible link connecting the two terminals, the lower end of the tube having an 30 inwardly extending flange embracing the rodlike terminal.

17. In a device of the class described, a tubular insulating member forming a fuse chamber, a movable disclike fuse terminal closing off one 35 end of the chamber, an annular ring for the opposite end of the member, a movable rodlike terminal projecting into said chamber through said ring, and a fusible link in said chamber connecting said terminals.

18. In a device of the class described, a tubular insulating member forming a fuse chamber, a movable disclike fuse terminal closing off one end of the chamber, an annular ring for the opposite end of the member, a movable rodlike terminal projecting into said chamber through said ring, a fusible link in said chamber connecting said terminals, means for retracting the rodlike terminal, and means for guiding said disclike terminal.

lar insulating member forming a fuse chamber, a movable disclike fuse terminal closing off one end of the chamber, an annular ring for the opposite end of the member, a movable rodlike terminal projecting into said chamber through said ring, a fusible link in said chamber connecting said terminals, and an annular ring forming a constriction for the end of the chamber adjacent said disc.

20. In a device of the class described, a tubular insulating chamber having an annular stationary terminal at one end, a movable disclike terminal engaging saidnstationary terminal, a movable rodlike terminal projecting into said chamber from the opposite end thereof, means for retracting said latter terminal, a fuse connecting said movable terminals, said chamber having an annular space about said fuse and said rodlike terminal, and arc extinguishing material disposed in said annular space.

21. In a device of the class described, a tubular insulating chamber having an annular stationary terminal at one end, a movable disclike terminal engaging said stationary terminal, a movable rodlike terminal projecting into said 19. In a device of the class described, a tubu-` chamber from the opposite end thereof, means for retracting said latter terminal, .a fuse con- 'necting said movable terminals, said chamber having an annular space about said fuse and said rodlike terminal, and arc extinguishing material disposed in said annular space, said arc extinguishing material comprising a liquid held within said annular space.

22. In a device of the class described, a closed fuse housing, a rst fuse terminal, means for guiding said .terminal centrally of the housing, a movable rodlike fuse terminal, a fuse link between said fuse terminals, a spring for moving said latter terminal, a body of liquid in the housing, and a liquid director for directing liquid upon the end of the latter terminal, said liquid director and rodlike terminal having lost motion connection to permit freedom of motion of the rodlike terminal throughout the first part of its motion.

23. In a device of the class described, a closed 'fuse housing, a fuse terminal at the upper end of the housing, means for guiding said terminal centrally of the housing, a fuse chamber adjacent said fuse terminal, a rodlike terminal projecting through an opening into the fuse chamber, a liquid director below said fuse chamber having a lost motion connection with said rodlike terminal, a body of arc extinguishing liquid in said housing, and a spring for withdrawing said rodlike terminal from said fuse chamber.

24. In combination a fuse housing, comprising a plurality of functionally separate chambers substantially closed off from each other, said chambers comprising a condensing chamber, an arc extinguishing chamber, and a disconnecting chamber, and electrodes forming the closures between the arc extinguishing chamber and other chambers, and a fusible link connecting said electrodes, said electrodes being separated upon blowing of the fuse.

25. In a device of the class described, a tubular arc extinguishing chamber, a fuse in said chamber, terminals for said fuse substantially closing the ends of said chamber, and secondary chambers at the ends of said rst chamber respectively into which the terminals are moved upon blowing of the fuse:

26. In combination, a. fuse chamber comprising a tubular casing, a fusible link therein, a fuse terminal projecting into the casing and substantially closing olf one end thereof, a second fuse terminal substantially closing off the other end of said casing, said fuse link connecting said terminals, and a charge of are extinguishing medium coniined within said chamber and out of contact with the fuse, a main fuse housing and means in the main housing for guiding one terminal axially in alignment with said chamber.

27. In combination, a tubular fuse housing comprising a sleeve of insulation having metallic ferrules at its ends, said ferrules forming external circuit terminals, a tubular fuse chamber disposed within said housing adjacent one end thereof, said chamber having a restricted opening adjacent one end, a movable rodlike fuse termi- Y nal projecting into said chamber through said 28. In a fuse the combination of a wall of insulation having an opening providing an annular choking restriction, a pair of arcing terminals in axial alignment with each other and the re- 5 striction, a fuse between said terminals, and means for driving astream of arc extinguishing uid through said restriction upon formation of an arc, said stream of uid preserving said restriction from the heat of the arc and tending to reduce the cross section of the arc.

29. In combination, a tubular member forming an arcing chamber, an annular choking restriction adjacent one end of the chamber, a ringlike conducting seat at the end of the chamber adjacent ,said choking restriction, an

external terminal connected to said seat, a disclike cover for the end of the chamber resting normally on said seat, an arcing tip carried by said cover, a guide for guiding said cover with the arcing tip substantially in axial alignment with the annular restriction, a movable terminal projecting into the ,chamber and being guided axially in alignment with said restriction, and a fuse between said arcing tip and said movable terminal.

30. In combination, a fuse housing, a pair of movable fuse terminals, a fuse between the terminals, means for guiding said terminals for f movement away from each other in axial alignment upon blowing of the fuse, means for holding one of said terminals after movement, said means providing an annular passageway about said one terminal, an arcing chamber embracing a portion of the arc and having a charge of arc extinguishing material which projects a stream of Ygaseous arc extinguishing medium about said arc, and about said one terminal and through said annular passageway.

31. In combination a pair of arcing terminals between which an arc is adapted to be drawn, means for moving one of said terminals along a definite path, a rst arc extinguishing material disposed along one part of the said path when the arc is initially formed, said material being adapted to become active from the heat of the arc only under relatively high rates of current iiow in the arc, and a second arc extinguishing material disposed along another part of the path of said terminals, said second arc extinguishing material being adapted to become active under lower rates of current ow in the arc.

32. In combination a pair of arcing terminals, means for retracting one of said kterminals from the other, and means providing a pair of bores be retracted successively in its movement, the rst bore being disposed adjacent the arc where the arc is initially formed and having a relatively high arc extinguishing effect upon heavy current ow in the arc, the second bore being remote from the initial location of the arc and having greater arc extinguishing eiect upon an arc of light current ow than the rst bore has.

33. In combination a fuse chamber having an external terminal, an internal contact forming a seat, a movable cover member for said seat, a fuse connected to said cover member, a fuse terminal for the opposite end of the fuse, means for tensioning the fuse to hold the cover members on its seat, means for guiding the cover member away from its seat, and a shunt path from said external terminal to said cover member, which shunt path is effective to carry current when the cover is raised from its seat.

34. In combination a fuse chamber having a through which the moving terminal is adapted to pair of fuse terminals, a fuse between them, a spring for moving one terminal, guiding means for controlling and limiting the movement of the other terminal, a stationary chamber adapted to embrace the fuse, one end of the arc caused on blowing of the fuse being carried outside the chamber by movement of said other terminal, and a charge of arc extinguishing material in the chamber through which the said one terminal is moved.

35. In combination, a stationary arcing chamber, a pair of terminals in said chamber between which terminals an arc is adapted to be established, means for guiding the first terminal out of the .chamber and holding the same in fixed alignment upon blowing of the fuse, means for guiding the second terminal in xed alignment in the opposite direction, and a charge of arc extinguishing material in said chamber.

36. In a fuse a stationary tubular arcing chamber, a stationary cooling and recombining chamber adjacent the arcing chamber, a movable terminal in said arcing chamber, a fuse connected at one end to said terminal, means acting upon blowing of the fuse in the arcing chamber to move the movable terminal from the arcing chamber into the cooling and recombining chamber, and carry with it the adjacent end of the arc.

37. In a fuse a stationary tubular arcing chamber, a stationary cooling and recombining chamber adjacent the arcing chamber, a movable terminal in said arcing chamber, a fuse connected at one end to said terminal means acting upon blowing of the fuse in the arcing chamber to move the movable terminal from the arcing chamber into the cooling and recombining chamber and carry with it the adjacent end of the arc, a charge of arc extinguishing material in said arcing chamber, said material being expelled in contact with the arc into the cooling and recombining chamber.

38. In a circuit interrupter, an arcing chamber in which an arc is drawn, an adjoining cooling and recombining chamber into which one arc terminal is withdrawn to help extinguish the arc, and another chamber containing a liquid dielectric into which the other terminal is withdrawn to prevent reestablishment of the circuit.

39. In a device of the class described, a glass sleeve having external terminals, a fuse chamber formed of brous insulation disposed within the upper end of the glass sleeve, said chamber having a substantially closed lower end and a fuse disposed in part within said chamber a movable fuse terminal for each end of the fuse chamber and means for guiding said terminals in alignment with each other.

40. In combination, a fuse housing, a' pair of fuse terminals, a fuse between the terminals, means for guiding one of said terminals for movement away from the other in axial alignment upon blowing of the fuse,means for holding the other of said terminals stationary, there being an annular passageway about saidsecond named terminal, an arcing chamber opening at one end into said passageway and being substantially closed at its other end during the continuance of the arc, said chamber embracing a portion of the arc and confining therein a charge of arc extinguishing material which projects a stream of gaseous arc extinguishing medium about said arc and about said latter terminal and through said annular passageway.

41. In a device of the class described, the combination of a housing comprising a tubular arcing chamber and a recombining chamber, said arcing chamber being substantially closed at one end during the continuance of the arc and having an outlet into the recombining chamber at the other end, a rst fuse terminal in said arcing chamber, a second fuse terminal substantially axially in alignment with said arcing chamber at all times, a fusible link normally connecting said fuse terminals and adapted to be fused to form an arc, said second fuse terminal providing a central arcing terminal for holding the arc in xed position centrally of the arcing chamber, and arc extinguishing material contained in said chamber and acted upon by the arc to form a gaseous medium which is projected into the recombining chamber past said arcing terminal.

42. In combination a fusible link, an arcing chamber for said link, arc extinguishing material contained in said chamber; said arcing chamber having a terminal for one end of the fuse, a recombining chamber into which one end of the arcing chamber opens, the other end of the arcing chamber being substantially closed during continuance of the arc, and a second fuse terminal providing an arcing tip in alignment with said arcing chamber, said arc extinguishing material being acted upon by the arc in said chamber to form a gaseous arc extinguishing medium which 1s projected in a blast upon said arcing tip and then passes beyond the same into said recombining chamber.

43. In combination a fusible link, a housing providing an arcing chamber for the arc formed upon melting, of the fusible link, arc extinguishing material in said chamber adapted to be acted upon by the arc therein to form a gaseous arc extinguishing medium, a recombining chamber, one end of said arcingchamber being substantially closed off to prevent the escape of gases therefrom, the other end opening into said recombining chamber, a fuse terminal for said closed end of the arcing chamber, and a second fuse terminal substantially axially in alignment with said open end of the arcing chamber for limiting the arc substantially to the arcing chamber and permitting the ow of gaseous arc extinguishing material into said recombining chamber.

44. In combination a fusible link, a housing providing anv arcing chamber for the arc formed upon melting of the fusible link, arc extinguishing material in said chamber adapted to be acted upon by the arc therein to formA a gaseous are extinguishing medium, a recombining chamber, one endof said arcing chamber being substantially closed off to preventthe escape of gases therefrom, the other end opening into said recombining chamber, a fuse terminal for said closed end of the arcing chamber, and a second fuse terminal substantially Aaxially in alignment with said open end of the arcing chamber for limiting the-arc substantially to the arcing chamber and permitting the flow of gaseous arc extinguishing material into said recombining chamber, the outlet of the arcing chamber having a constriction for restricting the outflow of said gaseous medium to prolong said flow to the time when the current iiow approaches zero.

45. 'In combination a relatively short fusible link, a tubular arcing chamber therefor substantially longer than the link, a movable rod-like terminal for one end of the link lying within one end of the chamber, said end of the chamber and said rodlike terminal forming a closure for the chamber while the arc persists, a spring for said rodlike terminal, a fuse terminal held substantially in alignment with the axis of the chamber at the other end thereof, a recombining chamber at said other end of the chamber for receiving the products of the arc expelled from 5 said one end of the chamber, and arc extinguishing material contained in said chamber to provide a gaseous arc extinguishing ymedium when the fuse is melted and an arc is formed.

46. In a fuse a tubular fuse chamber, a fuse l0 link in said chamber terminals for said link, one of said terminals being movable, a spring for moving said movable terminal toward one end of the chamber, a closed vessel of insulation containing arc extinguishing material disposed in lo said chamber out of contact With the fuse link, and means out of contact with the link for engaging said vessel from opposite directions to support the same in said chamber independently of said fuse link and the terminals therefor, said 20 chamber and said supporting means providing an open bore through which the products of the arc may be expelled.

47. In a device df the class described, a tubular arcing chamber, a fuse in the chamber, a pair 25 of terminals for the fuse, one end of the chamber being open for the release of products of the arc, an arc extinguishing material adapted to be acted upon by the arc to evolve a gaseous arc extinguishing medium, and a sealed Wrapper en- 30 closing said arc extinguishing material and being ruptured upon the occurrence of the arc, one of said terminals being in position to permit the gaseous arc extinguishing medium to sweep past the same in escaping from the open end of the 30 chamber.

48. In a device of the class described, a fuse, an arcing chamber for the fuse, terminals for the fuse, one of said terminals being a movable terminal, said arcing chamber having an opening 40 through its Walls, said movable terminal projecting through said opening into the chamber, and spring means for retracting said movable terminal to lengthen the arc within the arcing chamber when the fuse is melted, said movable 45 terminal having an enlargement adapted to be drawn into position to close said opening.

49. In combination, a main fuse housing, a fuse, a tubular arcing chamber for the fuse, a wicklike member in the chamber, a body of liq- 50 uid arc extinguishing material in the housing and wetting the lower end of the wicklike member, the lower end of the chamber having an annular valve seat, and a movable rodlike fuse terminal connected to the fuse in the chamber and 55 extending through said valve seat, said terminal having an enlarged portion serving as a valve to engage the valve seat and close off the end of the chamber.

50. In a device of the class described, a main 60 tubular housing, a fuse, a tubular arcing chamber for the fuse, said chamber being disposed Within the housing and having arr-apertured closure for one end, a movable rodlike fuse terminal extending through said aperture, a spring for 6., retraoting said rodlike terminal to extend`the arc caused by melting of the fuse, an arcextinguishingV material in the arcing chamber, and a valve carried by said rodlike terminal for closing off said aperture. 70

51. In a device of the class described, a main tubular housing, a fuse, a tubular arcing chamber for the fuse, said chamber being disposed within the housing, and having an apertured closure for one end, a movable rodlike fuse ter- 75 minal extending through said aperture, a spring for retracting said rodlike terminal to extend the arc caused by melting of the fuse, arc extinguishing material in the arcing chamber, a liquid dielectric outside the chamber in the housing, and closure for the aperture carried by the rodlike terminal.

52. In a device of the class described, a main tubular housing, a fuse, a tubular arcing chamber for the fuse, said chamber being disposed within the housing and having an apertured closure for one end, a movable rodlike fuse terminal extending through said aperture, a spring for retracting said rodlike terminal to extend the 'r arc caused by melting of the fuse, said rodlike terminal having a detachable portion for closing the aperture.

53. In a device of the class described, a main tubular housing, a fuse, a tubular arcing chamber for the fuse, said chamber being disposed within the housing, and having an apertured closure for one end, a movable rodlike fuse terminal extending through said aperture, and a spring for retracting said rodlike terminal to extend the arc caused by melting of the fuse, said rodlike terminal having a detachable tip forming a check valve for closing said aperture upon the retraction of the rodlike terminal by the spring.

54. In a device of the class described, a main tubular housing, a fuse, a tubular arcing chamber for the fuse, said chamber being disposed Within the housing and having a valve seat at one end, a movable rodlike fuse terminal extending through said valve seat and being connected to the fuse, a vbody of arc extinguishing material in the chamber adapted to be rendered active by the arc, and a body of dielectric in the main housing, said movable fuse terminal having a detachable tip engaging said valve seat and serving as a check valve between said main housing and said chamber.

55. In combination, a pair of terminals, a fuse between the terminals, a substantially tubular arcing chamber surrounding the fuse and having its ends substantially closed by said terminals, a spring for retracting one terminal, said fuse transmitting the spring pull to the other terminal tending to hold it in position to close the adjacent end of the chamber, and arc extinguishing material for producing a blast of fluid endwise through the arc and out of the end which is normally closed by said other terminal.

56. In combination, a pair of terminals, a fuse between the terminals, a substantially tubular arcing chamber surrounding the fuse and having its ends substantially closed by said terminals, a spring for retracting one terminal, said fuse transmitting the spring pull to the other terminal tending to hold it in position to close the adjacent end of the chamber, arc extinguishing material for producing a blast of iluid endwise through the arc and out of the end Which is normally closed by said other terminal, and a recombining chamber disposed beyondl said other terminal for receiving the uid discharged arc extinguishing material disposedl Aabout the walls of said arcing chamber but leaving a passageway about said fuse leading to said outlet, the arc extinguishing material adjacent the fuse having effectiveness for an arc of heavy current oW and the arc extinguishing material remote from said outlet having effectiveness for an'arc of light current ow.

58. In combination, a tubular arcing chamber having an outlet at one end and a closure at the other, a silver fuse disposed in the chamber substantially at said outlet, a recombining chamber into which said outlet discharges, a retractible terminal for the end of the fuse remote from the outlet, and arc extinguishing material in the arcing chamber.

59. In combination, a tubular arcing chamber having an outlet at one end and a closure at the other, a silver fuse disposed in the chamber substantially at said outlet, a recombining chamber into which said outlet discharges, a retractible'terminal for the end of the fuse remote from the outlet, arc extinguishing material in the arcing chamber, a disconnecting chamber at the end of the arcing chamber which has the closure, said retractible terminal extending through the closure, and means to move said retractible terminal out of the arcing "chamber and into the disconnecting chamber to introduce a disconnecting gap after the arc is extinguished.

60. In combination, a tubular arcing chamber .having an outlet at one end and a closure at the other, a sealed container enclosing arc extinguishing material disposed within the chamber there being an unobstructed longitudinal passageway through said chamber, said chamber being defined in part by said container, a fuse extending longitudinally of the chamber, and a movable terminal for drawing the arc formed upon melting of the fuse in said passageway and along the surface of the container to destroy said container and release the arc extinguishing material into the arc within the chamber.

6i. As a rell for a device of the class described, a tubular sleeve of insulation having an attaching coupling atx one end,. apertured heads for opposite ends of the sleeve, and one or more containers having arc extinguishing material sealed therein disposed within the sleeve and providing a central passageway.

62. In combination in a fuse, a tubular arcing chamber having an outlet at one end, -a fusible link disposed in said chamber, a normally sealed container for arc extinguishing material disposed in the chamber and adapted to be subjected to,

the arc caused by blowing of the fuse, said arc causing the container to be ruptured, terminals for the fuse, a disklike closure for said outlet carrying one of said terminals, and a spring for tensioning the fuse and holding said disklike closure over said outlet, said chamber providing a free passageway about the fuse leading to said outlet.

63. In combination ina fuse, a tubular arcing chamber having an outlet at one end, a fusible link disposed in said chamber, a normally sealed container for arc extinguishing material disposed in the chamber and adapted to be subjected to the arc caused by blowing of the fuse, said arc causing the container to be ruptured, terminals for the fuse, a disklike closure for said outlet carrying one of said terminals, a spring for tensioning the fuse and holding said disklike closure over said outlet, said chamber providing a free passageway about the fuse leading to said outlet,

and a fluid-tight main fuse housing enclosing said arcing chamber and said closure.

64. In a high tension fuse, a tubular fuse chamber having a terminal closing one end of the chamber, said chamber having an outlet at the other end, a movable terminal expellable by pres'- sure in the chamber normally plugging said outlet, fusible means in said chamber connected between said terminals, and arc extinguishing material in said chamber adapted upon blowing of said fusible means to form an arc extinguishing medium for expelling said second terminal from said outlet, said medium promptly evacuating the metal vapors of the fusable means fromv said chamber.

65. In a high tension fuse, a tubular arcing chamber having an opening at one end and having a valve seat associated with said opening, a

rst fuse terminal constituting a plug for said valve seat, a. second terminal extending into said chamber to a point adjacent said rst terminal, a fuse adapted to be put in tension connecting said terminals, a spring connected to said second terminal and tending to move it away from the first terminal, said spring tensioning said fuse to hold said rst terminal against its seat, and arc extinguishing material in the chamber, which material, when acted upon by the arc formed on melting of the fuse, evolves fluid pressure that removes the first terminal from said seat and renders the said opening effective, said medium promptly evacuating the metal vapors of the fuse from said arcing chamber.

66. In a high tension fuse, an outer sleeve of glass carrying terminal ferrules upon its ends, a renewable arc extinguishing chamber iixedly mounted in the upper end of said sleeve and containing a predetermined charge of arc extinguishing material therein, an upper and a lower terminal extending into said arc extinguishing chamber, means in said chamber fusible upon overloads to establish an are, said upper terminal being fixedly held in definite alignment axially of said chamber and said lower. terminal being flexibly connected with the lower ferrule andr being movable out of the lower end of said chamber to increase the length of the arc and the effective gap between said terminals.

67. In a high tension fuse, the combination of a closed condensing chamber, an associated arc extinguishing chamber adapted to discharge gases and vapors into the first chamber, fusible means in the second chamber for establishing an arc in a connected circuit to be interrupted, said second chamber containing a charge of arc extinguishing material limited to the amount necessary for extinguishing a short circuit arc, which charge of material is adapted to evolve a gaseous arc extinguishing medium in said second chamber and discharge the same through a part of the length of the arc andinto the first chamber, said rst chamber having means for cooling and condensing the gaseous medium discharged into it.

68. The combination with claim 67 wherein the amount of material is limited with respect to the capacity of the first chamber, so as to prevent the rise of fluid pressurein said first chamber above a predetermined value, and a pressure releasable vent for said first chamber, said cooling and condensingv means in said chamber being interposed between said vent and said second chamber to reduce substantially below the ignition point gases driven out of said second chamber by the arc.

69. 'I'he combination with claim 67 of a terminal for one end of the arc, means for withdrawing said terminal from the second chamber and creating an extended gap, and means for introducing a liquid dielectric in said gap to prevent reestablishment of the arc.

'70. A high tension fuse comprising a fusible conductor connected between terminals, one of which is retractable by a spring, an elongated tubular arcing chamber within one end of which, the fusible conductor is disposed, a condensing and expansion chamber normally sealed off from atmosphere, the arcing chamber discharging vapors and gases into the condensing and expansion chamber when the fusible conductor blows, the arcing chamber being provided with a relatively limited amount of arc extinguishing material which is progressively acted upon by the are, as the arc is lengthened in the arcing chamber by retraction of the spring actuated terminal, to form a gaseous medium which drives the metallic vapors from the arcing chamber into the condensing and expansion chamber and continuously drives fresh gaseous material through the arc to displace ionized material, the amount of arc extinguishing material available to the arc being correlated to the arcing chamber and to the condensing and expansion chamber, so as to permit the said material during usual operation of the device to be gasfied and driven through the arcing chamber and into the condensing and expansion chamber to effect the are extinguishing function and to do so without undue rise of pressure.

'71. In a high tension fuse, a tubular arcing chamber, a fuse in the chamber, fuse terminals substantially closing both ends of the chamber, a main housing at one end of the chamber, a spring in said housing connected to one terminal to retract the same, liquid dielectric in said housing, a recombining chamber at the other end of the chamber, means in said recombining chamber for guiding the second terminal in line with the tubular arcing chamber, and means presenting a large cooling area for vapors and gases driven out of thearcing chamber by said arc.

72. In a high-tension fuse, an arcing chamber having an outlet, a fuse, fuse terminals, one of which is movable in said chamber, a spring for moving said one terminal when the fuse melts, a cooling and condensing chamber communicating with said outlet, a charge of arc extinguishing material in said first chamber adjacent said fuse and limited in amount to. that necessary to extinguish an arc on a predetermined heavy current flow corresponding to short circuit, said sec- Aond chamber being so proportioned to said limited amount as to receive the gaseous medium evolved from said limited amount without generation of excessive pressures, and additional arc extinguishing material -available to be acted upon by an are of lower current value corresponding to overload, the gases evolved from said additional material being also discharged into said second chamber.

73. In a high tension fuse, a pair of terminals, a fuse between them, spring means for moving one of said terminals when the fuse melts to separate the terminals, a charge of arc extinguishing material adjacent the fuse and being limited to the amount necessary to extinguish an arc of predetermined heavy current ow corresponding to short circuits, and additional arc extinguishing material brought into cooperating relation with the arc by movement of said movable terminal for extinguishing an arc of lower current value corresponding to overload.

74. In combination in a high tension fuse, an arcing chamber having an outlet, a silver fuse, terminals for said fuse, one of said terminals being retractable from said outlet when the fuse is melted, a cooling and condensing chamber containing extensive cooling surfaces, a charge of arc extinguishing material limited to the amount necessary for extinguishing the arc upon predetermined heavy current flow corresponding to short circuit value, said second chamber being so proportioned as to receive and retain both the silver vapor andthe gases evolved from said material upon the blowing of the fuse by said predetermined heavy current ow.

75. In combination in a high tension` fuse, an arcing chamber having an outlet, a silver fuse in said chamber, a cooling and condensing chamber connected to said outlet, said second chamber having extensive metallic cooling surfaces for condensing the silver vapor evolved from blowing of the fuse by predetermined heavy current ow corresponding to short circuit.

76. In a circuit interrupter, a first terminal and a second rod-like terminal which is movable endwise away from the first terminal to extend fan arc formed between the terminals, a tubular pressure retaining chamber surrounding the second terminal, said second terminal extending through an opening in the bottom of the chamber, said chamber having a restricted opening at its upper end forming a constriction for an arc between said terminals and for fluid flow out of the chamber, and arc extinguishing material in the chamber for producing a gaseous arc extinguishing medium by the action of the arc thereupon, said first terminal being permanently associated with said latter opening to be impinged by the gaseous medium discharged therethrough.

77. The combination of claim 76 wherein the first terminal is movable and closes the latter opening but is moved endwise away from said opening by internal pressure in the chamber.

78. The combination of claim 76 wherein the arc extinguishing material is a liquid which partially fills the chamber and prevents blowing of the gaseous medium through the bottom opening of the chamber when the arc is established.

79. The combination of claim 76 wherein the first terminal closes and is sealed to. the chamber over the latter opening but is adapted to be moved endwise away from the opening by internal pressure in the chamber.

- 80. I'he combination of claim 76 wherein the said latter opening is defined by an outwardly flared nozzle of insulating material, said rst terminal being disposed axially in alignment with said nozzle to be impinged by the gaseous medium discharged through said nozzle.

81. The combination of claim 76 with an outer housing containing spring means for actuating the rodlike terminal, said outer housing being mechanically rigid with but substantially closed off from the tubular pressure retaining chamber to the extent that the said outer housing is not subjected to pressure of-the gaseous arc extinguishing medium in the said tubular chamber when the arc is formed.

82. The combination of claim 76 with an outer insulating housing containing spring means for actuating the rodlike terminal, said outer housing being mechanically connected with said tubular chamber but substantially closed oil' from the tubular chamber to the extent that the said outer housing is not subjected to the pressure of the gaseous medium in said tubular chamber When the arc is formed, said outer housing containing a bath of insulating liquid into which the rodlike terminal is retracted to interpose a portion of said insulating liquid for the electrical disconnection of said terminals from each other.

83. In a circuit interrupter, a pair of terminals between which an arc is adapted to be drawn, the second of said terminals being a rodlike terminal movable endwise away from the iirst terminal to extend the length of the arc, a tubular chamber having an outlet at its upper end through which a gaseous medium is adapted to be discharged beyond the first terminal, said chamber having a bottom opening through which said rodlike terminal projects, a wicklike member disposed longitudinally inside the chamber and serving to provide for the evolution of gaseous medium therefrom when the arc carries heavy current iiow, and a body of liquid wetting the lower end of the wicklike member and tending to prevent the discharge of gaseous medium through the bottom opening, said liquid serving to provide for the evolution of gaseous medium therefrom when the arc carries light current flow and serving as an insulating medium between the rodlike terminal and the first terminal to prevent reestablishment of the arc after the arc is extinguished.

84. In a circuit interrupter, a tubular arcing chamber adapted to be disposed substantially vertically, said chamber having an outlet at its upper end, a first terminal permanently associated with the outlet substantially in axial alignment with the outlet whereby gaseous'medium discharged from the chamber impinges the terminal and escapes beyond the terminal, a closed recombining chamber connected to the upper end of the first chamber for receiving the gaseous medium discharged therefrom, the bottom of the rst chamber having an opening, a rodlike terminal projecting through said opening into the first chamber, and a body of are extinguishing material in said chamber from which material a gaseous arc extinguishing medium is evolved by an arc between said terminals.

85. The combination of claim 84 wherein the ar'c extinguishing material comprises a body of liquid in the first chamber which liquid tends to seal the bottom opening against the escape of gaseous medium therethrough.

86. The combination with claim 84 of a substantially closed spring housing which is mechan-v ically connected to said recombining chamber but sealed oi therefrom and from the outlet of said arcing chamber to prevent the said spring housing from receiving products of the arc discharged through said outlet, and spring means within the spring housing for moving said rodlike terminal.

87. The combination with claim 84 of a substantially closed disconnecting chamber below said arcing chamber and into which said rodlike terminal is withdrawn, said disconnecting chamber containing a body of insulating liquid substantially filling the same.

88. In a circuit interrupter a tubular chamber having one" end provided with an outlet for the discharge of gaseous medium, the other end having a central opening, a pair of terminals between which an arc is adapted to be drawn, comprising a first terminal permanently associated with said outlet and being adapted to be impinged by the gaseous medium discharged from the chamber through said outlet and a second terminal comprising a rodlike member projecting through and substantially closing said central opening and disposed substantially in axial alignment with said first terminal and movable endwise of said chamber and away from the rst terminal, and arc extinguishing material in said chamber adapted to be acted upon by the arc to evolve a gaseous medium which is discharged in contact with the arc and out of said outlet beyond the irst terminal.

89. The combination of claim 88 wherein the arc extinguishing material comprises a bath of liquid into which the rodlike terminal is withdrawn after the arc is extinguished.

90. The combination of claim 88 wherein the said other end of the tubular chamber has closure means in which said central opening is formed said rodlike terminal cooperating with said closure means substantially to prevent the. escape oi' fluid at said end of the chamber.

91. 'Ihe combination of claim 88 wherein the outlet of the tubular chamber is deilned by an insulating ring .forming a nozzle for directing the gaseous medium at high velocity out of the chamber and against the first terminal, and for constricting the arc.

92. In a circuit interrupter a pair of terminals between which an arc is adapted to be drawn, the second of said terminals being a rodlike terminal movable endwise away from the first terminal to extend the length of the arc, a tubular chamber having an outlet at its upper end through which a gaseous medium is adapted to be discharged beyond the iii-st terminal, said chamber having a bottom closure provided with opening through which said rodlike terminal projects, and a body oi' arc extinguishing liquid in the lower end of the chamber for forming a gaseous arc extinguishing medium and tending to prevent the discharge of said gaseous medium through said bottom opening about said rodlike terminal.

93. 'Ihe combination of claim 92 with wicklike means disposed longitudinally of said tubular chamber and being wet by the liquid in the lower end of the chamber.

94. In a circuit interrupter, a pair of terminal members provided with ends between which an arc is adapted to be produced, an arcing chamber having an opening at one end, one oi said terminal members being maintained permanently in axial alinement with said opening, the other terminal member comprising a rodlike element projecting through the lower end of the chanber, said otherend of the chamber beingclosed to prevent the escape of gaseous medium therethrough when the arc is produced, and arc extinguishing material ih said chamber adapted to be acted upon by the arc to evolve a gaseous arc extinguishing medium, said material being not substantially in excess of the amount required to extinguish an arc which carries heavy current flow.

95. In a circuit interrupter, a pair of terminal members between which an arc is adapted to be produced, a tubular arcing chamber having an opening at the upper end, the upper terminal member being associated with said opening,

4whereby gaseous medium discharged from said opening is directed upon said upper terminal member, the other terminal member comprising a rodlike element projecting into the chamber through an opening in the lower end thereof, means for retracting the rodlike element through and out` of the opening in the lower end of the chamber, means for maintaining a bath of insulating liquid at a level lying adjacent the bottom of the chamber, and a liquid director outside the chamber having a lost motion connection with the rodlike element whereby the liquid director is moved downward only after the rodlike element has moved out of the chamber.

96. In combination with a main tubular housing, a tubular arcing chamber of smaller internal diameter than the main housing supported upon the upper end of said main housing, a pair of terminals between which an arc is adapted to be formed associated with said chamber, said terminals comprising an upper terminal and a movable rodlike terminal projecting up through the bottom of the arcing chamber, means for moving y the rodlike terminal downwardly beyond the lower end of the arcing chamber, a liquid director approximately filling the bore of the main tubular housing and being initially held adjacent the lower end of the arcing chamber, said liquid director having a central portion loosely guided on said rodlike terminal and said rodlike terminal i having shoulders at its opposite ends for providing a substantially i'ree lost motion connection, the arcing chamber having an opening at its upper end through which a gaseous medium vis adapted to be discharged during the existence of the arc, and a body of liquid substantially iilling the main housing and extending into the arcing chamber to a point below said opening.

97. In a circuit interrupter, a pair of terminals between which an arc is formed, a liquid arc extinguishing material, means for withdrawing one terminal into said material for lengthening the arc, a stationary restricting tubular chamber of insulation surrounding a portion'oi the are and through which chamber gases evolved by the action of the arc upon said liquid may fiow in a direction away from said moving terminal into a free space,the other terminal being permanently associated with the tubular chamber in position to be impinged by the gases discharged from said chamber.

98. In a circuit interrupter, an arcing chamber, arcing terminals associated with said arcing chamber and between which terminals an arc is adapted to be drawn in said chamber, one of said terminals being movable longitudinally of the chamber, said chamber having an opening through its walls, said movable terminal projecting through said opening into the chamber, means for retracting said movable terminal to lengthen the arc within the chamber, and means associated with said movable terminal for positively closing said opening when said movable terminal is retracted.

9 9. 'The combination of claim 98 wherein said movable terminal is movable beyond the end of the arcing chamber to interpose a disconnecting gap between the movable terminal andthe chamber externally of the chamber. i

extinguishing material in the chamber, arcing terminals associated with the chamber and be;- tween which an are is adapted to be drawn in said chamber, one of said terminals being movable 'longitudinally of said chamber, spring means for moving said movable terminal rapidly longitudinally of said chamber, 'and'means for retarding the rate at which said spring means moves the terminal when said terminal reaches the end of th;- chamber. A

HUGH A. TRIPLETT.

100. In combination, an arcing chamber, arc

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