US2353528A

US2353528A - Circuit interrupting apparatus

Info

Publication number: US2353528A
Application number: US444854A
Authority: US
Inventors: Hugh A Triplett
Original assignee: SCHWEITZER CONRAD Inc
Current assignee: SCHWEITZER CONRAD Inc; SCHWEITZER-CONRAD Inc
Priority date: 1942-05-28
Filing date: 1942-05-28
Publication date: 1944-07-11
Anticipated expiration: 1961-07-11

Description

July 1l, 1944- H. A. TRlPLET-r '2,353,528

CIRCUIT INTERRUPTING APPARATUS July ll, 1944.

H. A, TRIPLETT `2,353,528 CIRCUIT INTERRUPTING APPARATUS Filed May 28, 1942 5 Sheets-Sheet 2 July 11', 1944. H, A, TRiPLET-r n 2,353,528

CIRCUIT INTERRUPTING APPARATUS Filed May 28, 1942 5 Sheets-Sheet 5 U BY f WW im July 1l, 1944. H. A. TRIPLETT CIRCUIT INTERRUPTING APPARATUS Filed May 22a,` 1942 5 Sheets-Sheet 5 mw v INVENTOR. v?. Tz/OSZLT BY im@ MMM Patented July 11, 1944 2.353.528 cnwm'r m'raaammo APPARATUS Hugh A. Triplett, Wllmctte. lll., assigner to Schweitzer-Conrad, Inc., Chicago, Ill., a corporation of Delaware Application May 28, 1942, Serial No. 444,854

(Cl. 20o- 120) 24 Claims.

lb invention relates, generally. to circuit interrupting apparatus and it has particular relation to high voltage circuit interrupters in which the circuit opening is initiated by the blowing of one or more fusible elements.

An object of my invention is to provide for releasing an arc extinguishing nuid and for directing it into the arc space along a substantially straight and undeviating path.

Another object of my invention is to provide lor lost motion between a reservoir containing a material which when released is an arc extinguishing medium and a tubular terminal through which the arc extinguishing fluid is released into the arc space in order to etl'ect the release of the arc extinguishing fluid when the tubular terminal member has moved to a predetermined position.

A further object of my invention is to provide for hermetically sealing the reservoir to the tubu lar terminal member while still permitting relative movement therebetween to eil'ect release of the arc extinguishing uid.

It is also an object of my invention to provide an improved form of low temperature fusible element construction for a high amperage fuse.

Still another object of my invention is to pro- Vide a low resistance conducting path to the movable tubular terminal member of a circuit interrupter both before the terminal member moves to extend and extinguish the arc and while it is moving to the open circuit position.

A further object of my invention is to provide for cooling and condensing the products of the arc formed o'n operation of a circuit interrupter by passing the same through a restricted passageway one of the walls of which at least is formed of material which is capable of evolving an arc cooling medium due to the heat of the arc products.

A still further object of my invention is to provide for arresting the movement of the reservoir containing the arc extinguishing fluid and to permit the tubular terminal member to continue to move to effect release of the arc extinguishing fluid.

Other objects of my invention will, in part, be

obvious and in part appear hereinafter.

For a more complete understanding of the nature and scope of my invention reference can be had to the following detailed description taken in connection with the accompanying drawings in which:

Figure l is a view, partly in section and partlyk in front elevation, showing one embodiment of my invention;

Figures 2 and 3 are top and side views of a piercing pin and support solder therefor arranged to be mounted at the end of the tubular terminal of the circuit interrupter shown in Figure l for piercing the diaphragm of the reservoir or capsule containingy the material which when released is an arc extinguishing fluid;

Figure 4 is a view, in side elevation, of the circuit interrupter shown in Figure 1:

Figures 5 and 6 are views, in side elevation, of the upper line terminal showing the movable stop in different positions;

Figure 7 is a top plan view of the and its support as shown in Figure 5; e

Figures 8A and 8B, taken together, are a lef-..-n gitudinal sectional view of another embodimen.,h 0i' my invention; and

`Figures 9A and 9B, taken together, are a. 1ongitudinal sectional view of still another embodiment of my invention.

Referring now particularly to Figures 1 and 4 of the drawings, it will be observed that the circuit interrupter construction there shown is similar to one of the embodiments of circuit interrupter construction disclosed in my copending application, Serial No. 224,696, flled August 13, 1938. The circuit interrupter here shown comprises upper and lower terminals Il and I2 that are mounted on suitable insulators Il and Il which are carried by a suitable base member IB, such as a channel iron base. On the lower terminal I 2 there is mounted a replaceable fuse cartridge shown generally at I6.

The replaceable fuse cartridge 'I0 comprises a housing I1 of suitable insulating material, such as a fiber lined "Bakelite tube, having a termimovable stop nal Il at its lower end which is adapted to be secured to the lower terminal I2 by clamp means, shown generally at 20. At its upper end the insulating housing I1 is provided with a metallic ferrule 2| having an eye portion 22 integrally formed therewith for receiving a hook stick for placing the cartridge in operative position and for removing it therefrom.

Within the insulating housing i1 there is a liner of solid arc extinguishing material, such as magnesium borate or boric acid, in the form of rings 26 which are stacked one above the other so as to provide a bore 21' therethrough. A tubular terminal member 2B is mounted for movement through the bore 21 and it is provided with a central longitudinally extending opening or passageway 29 for a purpose which will presently be apparent. yIt will be observed that the tubular terminal member 28 is prevented from upward movement relative to the terminal member i8 by a strain wire 30. A fusible element Il, preferably in the form of a silver wire, interconnects the terminal member Il and the tubular terminal member 28 to provide a calibrated fusible section.

Near its upper end the tubular terminal member' 28 .is threaded into a two-armed contact member 32 which is arranged to cooperate with spring-biased contact lingers l! that are carried by the upper terminal Il. During the normal operation of the circuit interrupter the principal portion of the current flowing between the terminals il and l2 flows through the contact fingers il and contact member 32 into the tubular terminal member Il.

It will be observed that a sleeve I1 is threaded onto the upper side of the contact member 32 and that this sleeve is provided with integrally formed oppositely extending arms il which interfit with suitably shaped slots in a yoke Il. The yoke il is provided with oppositely extending shafts 4l which are mounted in suitable bearings Il carried by the upper terminal Il. Coilsprings 42, act between the shafts 4l and the bearings Il. By means of the coil springs Il it will be observed that the tubular terminal member 1l is normally biased upwardly but that auch movement is restrained by the strain wire ll. On flow of predetermined current in the circuit in which the circuit interrupter is connected the fusible element Il will be fused. This will be followed by fusion of the strain element 3l..

'Ihereupon the tubular terminal member 2l will be restrained no longer but will be withdrawn through the bore 21 by the springs Il. The arc incident to the circuit interruption will be drawn between the lower end of the tubular terminal member Il and the terminal member 'Il at the lower end of the insulating housing l1.

The present invention is particularly directed to the provision of means for assisting in extinguishing relatively low current arcs between the terminal members Il and 2i and also for scavenging the walls of the bore 21 after the arc has been interrupted so as to remove therefrom conducting particles and foreign material which might form a conducting path tending to facilitate subsequent breakdown or iiashover. In order to effect this desired operation a reservoir or capsule I3 is mounted in the sleeve I1. The reservoir or capsule I3 contains a material, such as carbon dioxide, which, when released. forms an arc extinguishing fluid. A rupturable diaphragm M seals the reservoir or capsule I3. It will be understood that any suitable reservoir or capsule I! can be employed such as the Sparklet type of capsule that is now on the market. It will be understood, however, that other type! of reservoirs or capsules can be employed. The reservoir or capsule Il is held in place by a coil compression spring 4l. In order to seal the reservoir or capsule Il to the tubular terminal member Il and at the same time permit relative movement therebetween a flexible bellows 4t is provided, as shown, 'for enclosing the upper end of the reservoir or capsule Il. The flexible bellows Il is secured, as by soldering, to the upper end of the sleeve I1.

In order to puncture the diaphragm M a pin or needle 41 is carried on a bridge ll, Figures 2 and 3, which is located at the upper end of the tubular terminal member 1I. The pin or needle 41 may be any suitable sharp instrument such as a phonograph needle which will penetrate the diaphragm 4| and rupture the same.

It will be understood that, because of the coil compression spring il, the reservoir or capsule Il moves upwardly with the tubular terminal member 2l under the influence of the coil springs 42 after the strain element Il has blown. After the tubular terminal member 2l has been moved upwardly through the bore 21 for a considerable distance, it is desirable to rupture the diaphragm 4I and release the arc extinguishing fluid. In order to accomplish this a stop Il ia mounted on abracket Il, Figure 5, extending from the upper terminal Il and is arranged, as shown. in the path of upward movement of the upper end of the flexible bellows 4l. When the tubular terminal member 2l is moved upwardly sufilciently far to have the upper end of the flexible bellows l. engage the stop 4I, further upward movement of the reservoir or capsule Il is prevented. However. because of the coil comp'ression spring Il and the flexible bellows It. the tubular terminal member I8 continues to move upwardly a slight distance during which time the pin or needle l1 is caused to rupture the diaphragm Il. The arc extinguishing material within the reservoir or capsule Il is then released and it flows directly through the passageway il into the arc space between the terminals Il and 2l. Since the arc extinguishing fluid is a non-conductor, it materially asista in extinguishing the arc, particularly lcw current arcs. by nlling the arc space with a non-conducting medium. and, because of the blast action of the released arc extinguishing material, the conducting particles in the arc space are blown out of the lower end of the bore l1. In addition. after the arc has been extinguished the arc extinguishing nuid will continue to flow from the reservoir or capsule Il through the passageway il under considerable pressure. 'I'his will scavenge the walls of the bore 21 and blow out conducting particles or carbon deposits which might tend to form a conducting path that would facilitate arcover or breakdown at a later time.

As indicated hereinbefore the two armed contact member 32 and the contact nngers J8 form the main conducting path between the tubular terminal member 2l and the upper terminal Il. Shortly after the tubular terminal member 2l begins to move upwardly, the contact member Il disengages the spring contact fingers Il. All of the current is then transferred to the arma il and the yoke Il. With a view to providing a low resistance path between the yoke II and the upper terminal Il, a flexible conductor Il interconnects the yoke it and one of the bearings ll. It will be understood that the flexible conductor Il carries substantial current only during the circuit interrupting operation after the contact member l2 has disengaged the contact fingers Ii.

After the circuit interruption has been completed, the tubular terminal member il is held in the upper position against the stop Il by the coil springs 42.

In order to facilitate replacing the blown cartridge il it is desirable to provide means for removing the arms Il from the yoke Il. For this purpose the stop l0 is pivoted at I2. Figure s, on me bracket n ma has s ring sa integrally formed therewith into which the prong of a switch stick can be inserted for moving the stop Il from the position shown in Figure 5 to that shown ln Figure 6 of the drawings. Normally the stop Il tends to swing downwardly under the influence of gravity and is held in the position shown in Figure 5 of the drawings by an ear Il which engages the central iiange portion il of the bracket BI.

When the stop Il is moved to the alternate position as shown in Figure 6 of the drawings, the yoke I! is permitted to move upwardly until the stops Il integrally formed 'therewith engage the undersides of the bearings 4l.

assasas The prong of the hook stick then can be inserted in theeye 22 and, after the clamp 2l has been released. the blown cartridge il can be removed and replaced with an unblown cartridge.

It will be understood that the positions of the stops Il are such relative te the bearings Il that, before the stop 4l is moved from the position shown in Figure 5 of the drawings, and the cartridge I. has blown, they are spaced a slight distance from the underside of the bearings Il. This insures that the pin or needle 41 can be moved through the full stroke to rupture the diaphragm Il. The upward thrust of the springs 42 is arrested solely by the stop 4s in the first instance. After the stop Il is moved to the alternate position shown in Figure 6 of the drawings, the yoke Il then moves upwardly slightly under mise the undersides of the bearings 4I.

It will be understood that, as soon as the prong .of the switch stick is removed from the eye ring Il, the step v4l will immediately swing downwardly under the innuence of gravity. There is then no likelihood that the operator will forget te replace the stopv Il since it is automatically restored to its operative position, While the stop Il will engage one side of the flexible bellows 4l in the released position, this does not interfere with the removal of the cartridge il.

The clamp 2l can be of any suitable type. The construction shown is described in more detail in Patent No. 2,147,316, of Allan Ramsey. It includes a clamp arm Il having an integrally formed socket portion Il for receiving the prong of a switch stick. The clamp 2l while providing a low resistance conducting path between the terminal member Il and the lower terminal I2 still permits a slight oscillation of the cartridge' I6 as is required by the swinging yoke l! in moving from one position to another during the circuit interrupting operation.v

With a view to facilitating the positioning of the cartridge II in operative position the terminal member il is provided with oppositely extending arms 02 which are arranged to interiit with suitable recesses in arms extending from the lower terminal i2. By this means the position of the cartridge il can be accurately determined.

In Figures 8A and 8B of the drawings there is shown a circuit interrupter construction in which several novel features are incorporated. The circuit interrupter is indicated, generally, by the reference character Il and is so designed andconstructed that it can be placed in and removed from standard fuse clips mounted on suitable line terminals. The circuit interrupter 10 is intended to be removed as a unit and replaced by a new or rebuilt cartridge of the same type and character.

It will be observed that the circuit interrupter 1I comprises terminals Ii and l2 which may be formed of copper tubing and which are adapted to be located in the respective fuse clips. Metalliv,` iittings Il and 14 are threaded into the ends of the tubular terminals ll, and 12, as shown. The fittings 13 and Il are interconnected by an insulating sleeve Il of fiber or similar material, the

` the influence of the springs 42 until the stops M ends of the outer sleeve 11 are provided to make a weathertight connection with the fittings 13 and Il Within the inner sleeve Il there is provided a body of solid arc extinguishing material in the form of rings l of magnesium borate or boric acid. The rings 'il are stacked one above the other in alignment to provide a bore .Il through which a tubular terminal member Il is arranged to be retracted for the purpose of extending and extinguishing an arc therein. 'I'he tubular terminal member Il is provided with a centrally located passageway l! for the purpose of conducting an arc extinguishing fluid into the arc space from a suitable reservoir for assisting in extinguishing the arc as will be described more in detail hereinafter. At the lower end of the tubular terminal member Il the centrally located passageway l! branches off into angularly directed nttings 'Il and 14 being threaded into the ends of the insulating sleeve Il as illustrated. Surrounding the sleeve 1I is another sleeve ll of insulating material. The sleeve 1l may be formed of a phenolic condensation product such as "Bakelite. A sleeve 11 of suitable insulating material such as glass or porcelain surrounds the sleeve ll and provides a weatherproof covering having high dielectric characteristics. Gaskets ll at the openings or apertures Il which, in combination with an opening Il in a terminal fitting B6, direct the arc extinguishing fluid both along the walls of the bore Il and over the fitting 8l and facilitate scavenging of the surfaces thereof.

The tubular terminal member Il is held in place by a strain element Il one end of which is secured over a pin extending transversely through the lower end of the tubular terminal member Il. It will be noted that the transverse pin l5 is located at the top of the terminal fitting 88 which ls threaded into the lower end of the tubular terminal member ll. The lower end of the strain element 8l is secured over a pin 8l which extends transversely through a terminal fitting ll that is held by a nut Il in place on a metallic spider Il. The spider 90 is secured by means of screws 0I to the fitting Il to which the lower terminal tube Il is connected as previously described.

The terminal fittings 08 and 8l are interconnected by a plurality of fusible elements 02. It will be observed that the fusible elements l2 are bowed inwardly intermediate their ends in order to provide the required length for the required timeA current characteristics with given spacing between the terminal fittings I6 and B8. The fusible elements 82 are located symmetrically in the terminal fittings Il and I8 about the centrally located strain element u.

Preferably the fusible elements 82 each comprise an outer sleeve of high melting point metal such as 'silver and a core of low melting point metal such as tin. The details of construction of such a fusible element are set forth in my Patent No. 2,243,135, and Patent No. 2,243,107, of Sigurd I. Lindell. The combination of a silver sheath and a tin core provides a high conductivity fusible element which operates at a relatively low temperature. Such a fusible element is particularly desirable in fuses the normal current carrying capacity of which is of the order of 400 to 600 amperes.

It will be observed that the metallic spider Il is provided -with apertures 98 therein. These apertures are provided to permit the free escape of the products of the arc formed between'the terminal fittings 86 and It when the strain and fus'ble elements M and 92 have blown. The

products of the arc comprise incandescent gases and metallic particles as well as 'arc extinguish- .ing fluid such as water vapor evolved from the a walls of the ,bore Il. It is desirable to cool and condense these products cf the arc before they are permitted to escape to the atmosphere so as to' reduce the fire hazard to a minimum and prevent arcing over to other energized conductors. For this purpose the products of the src are caused to ow through a relatively narrow passageway 91 between the inner surface of the terminal sleeve 12 and the outer surface of a body of solid arc` extinguishing material, such as magnesium borate or boric acid, formed by a stack of rings 98 of this material. These rings Il are centrally located on a suitable stud and are held in place by a nut |00 at the upper end as shown. The stud 09 is threaded into a closure member |0| which in turn is threaded into the lower end of the terminal sleeve 12. Apertures |02 in the closure member |0| serve to vent the passageway 91 to the atmosphere. The use of solid arc extinguishing material such as boric acid or magnesium borate for cooling and condensing the products of the arc provides a beneficial effect in that water vapor is evolved therefrom due to the heat of the products of the arc which tends to further cool and condense them and to suppress ames which might otherwise escape to the atmosphere.

At its upper end thetubular terminal member Il is threaded into a metallic sleeve |00 which has an integrally formed radially extending flange |01. A coil compression spring |00 is strained between the underside of the iiange |01 and the upper surface of the ntting 12 and acts to bias the tubular terminal member 0| upwardly. It will be recalled that the strain element Il interconnects the terminal fittings 00 and 00 and it will be understood that the upward movement of the tubular terminal member 0| is restrained as long as the strain element 04 remains intact. The provision of the strain element Il relieves the fusible elements $2 of the application of any tension stress.

Since the circuit interrupter is intended for use in circuits in which the normal current carrying capacity is relatively high, such as 400 to 600 amperes, it is desirable to provide a low resistance high conductivity path between the tubular terminal member Il and the sleeve terminal 1|. For this purpose the sleeve |06 is provided with an enlarged portion the outer surface I 09 of which forms a contact surface adapted to have contact engagement with flexible main contact fingers ||0 that are carried by the fitting 13 and extend upwardly from its upper surface as shown. The main contact fingers ||0 are curved adjacent their upper ends for receiving a garter spring which serves to bias the contact fingers ||0 into intimate contact engagement with the contact surface |00.

While it is desirable to have intimate contact engagement between the main contact fingers ||l and the contact surface |09 prior to circuit interruption, it is also desirable to relieve the contact pressure incident to this contact engagement so that the tubular terminal member 8| can move upwardly freely and quickly to extend and interrupt the arc. For this purpose the sleeve |06 is provided with a reduced section ||2 so that after the rod-like terminal member 8| is moved upwardly a short distance the upper ends of the main contact fingers ||0 no longer engage the sleeve |00.

Now it is desirable that there be provided a relatively low resistance conducting path between the tubular terminal member 0| and the terminal sleeve 1i while the former is moving upwardly through the bore 80 to perform the circuit interrupting operation. In the past it has been customary to employ one or more flexible conductors to perform this function. In

the circuit interrupter shown in Figures 8A and 8B of the drawings I have dispensed with the conventional form of flexible conductor and have provided auxiliary contact fingers III which extend downwardly from a ring Ill' that has a'lpress fit with the fitting 10. 'Ihe lower ends of the auxiliary contact fingers III are curved for receiving a garter spring lil which acts to urge the contact fingers into good contact engagement with the outer surface of the tubular terminal member 0| as it moves upwardly through the bore Il. It will thus be seen that the main contact fingers |I0 provide the normal current carrying path between the tubular terminal member 0| and the tube terminal 1|. At the same time the auxiliary contact fingers H3 assist in this current carrying function. The auxiliary contact members III are not of sufficient size and number to efficientlyperform this function alone. However. the auxiliary contact members ||l have sufficient current carrying capacity to carry the fault current during the relatively short interval such as a few cycles while the tubular terminal member 8| is moving upwardly through the bore 0I and the arc incident to the circuit interruption is being extinguished With a view to assisting in extinguishing low current arcs and to scavenging the walls of the bore 00 after the arc has been extinguished a reservoir or capsule ||1 is provided in the upper end of the sleeve |00 as shown. The reservoir or capsule ||1 may be of the ISparklet type and is arranged to contain a material, such as carbon dioxide, which when released forms an arc extinguishing fluid and flows through the passageway 02 and apertures 00 into the bore Il and arc space. The reservoir or capsule ||1 is provided with a frangible diaphragm III which can be punctured for releasing the contents. A coil compression spring Ill reacts between the lower 'end of the reservoir or capsule ||1 and the upper surface of a spider |20 located between the tubular terminal member 0| and the sleeve |00 for maintaining the reservoir or capsule ||1 in spaced relation with respect to a pin or needle |2| carried by the spider |20. The reservoir or capsule I |1 is hermetically sealed in place by a flexible bellows |22 which, while permitting relative movement between the reservoir or capsule ||1 and the tubular terminal member 0| prevents the escape of arc extinguishing duid in any direction except through the ypassageway 02.

When the strain and fusible elements Il and 02 are blown, the coil compression spring Ill moves the tubular terminal member 0| upwardly through the bore 00 and an arc is drawn between the terminal fittings 0l and l0. Because of the coil compression spring IIS, the reservoir or capsule ||1 moves upwardly with the tubular terminal member 8| and in spaced relation thereto. Near the upper end of the stroke the upper surface of the fiexible bellows |22 engages the under side 0f a disc |25 threaded onto a stem |20 which projects through a closure member |21 at the upper end of the tube terminal 1|. A coil compression spring |20, which normally biases the disc |25 downwardly, is compressed and a cap |29 at the upper end of the stem |26 is raised. The raising of the cap |20 indicates that the circuit interrupter 10 has operated and that it upward movement of the reservoir or capsule Ill permitted. However, the coil compression spring III continues to move the sleeve III and tubular terminal member Ii upwardly through a limited extent because of the provision of the coil compression spring ill and the ilexible bellows |22. 'Ihe pin or needle III then pierces the diaphragm III and ruptures the same whereupon the contents of the reservoir or capsule III are released and the arc extinguishing fluid flows through the passageway l2 into the -arc space where it performs thefunctions described hereinbefore.

Referring now particularly to Figures 9A and B of the drawings, it will be observed that the reference character Ill, generally, designates a circuit interrupter which comprises an insulatv ing housing I of glassor porcelain having a terminal I at its upperend and a terminal I at its lower end.

With a view to interconnecting the tubular terminal member III and the ttlng I after the contact member Ill has moved out of engagement with the contact lingers I, a flexible conductor I It is provided and connected, as shown, to the iltting I at-the upper end and to the ntting III at the lower end. The exible conductor I is coiled about the tubular terminal member IIJ so as to provide suiilcient length sion I'II.

Within the insulating -housing I thereis a replaceable cartridge, indicated generally at H1. The cartridge I" comprises a two layer sleeve Ill of insulation having a terminal I at its upper end arranged to have contact engagement with the terminal I at the upper end of the housing I". At its lower end the insulating sleeve I has a terminal I" in the form of a metallic sleeve which is arranged to be clamped to the lower terminal I on the housing IM. Within the insulating sleeve I there are rings III of arc extinguishing material, such as magnesium borate or boric acid, which are stacked one above the other and provide a bore il! centrally thereof.

A tubular terminal member Ill' is arranged to be movably mounted within the bore Il! and it is held in place therein. as shown, by a strain wire III which is supported by a cross-pin Ill carried by the terminal I". A fusible element I, preferably in the form of a silver wire, interconnects the terminal member I and the tubular terminal member I" and forms the principal current carrying element therebetween and is arranged to be fused under certain predetermined overload or short circuit conditions as is readily understood. The tubular terminal member Ill is provided with a centrally located longitudinally extending aperture or passageway II'I through which an arc extinguishing medium is discharged to assist in arc extinction as will be y presently described.

terminal member III is slidably mounted in a dtting III. The fitting III is arranged to be biased downwardly to carry with it the tubular terminal member I by a coil compression spring Il! which reacts between the upper face of the tting III and the underside of a iltting III threaded onto the lower end of the insulating sleeve III. It will be observed that the sleevelike lower terminal member III of the cartridge I" is threaded onto the fitting III so as to make good electrical contact engagement therewith. Contact fingers I project downwardly from the fitting Ill and are arranged to have oontact engagement with a'cylindrical contact member Il! carried by and secured to .the tubular terminal member III. By means of the contact nngers i and contact member Ill the tubular terminal member Il) is directly connected through a relatively low resistance path to the lower terminal member Ill and thence tothe lower line terminal I".

' reservoir or capsule Threaded' into the lower end of the extension Ill is a tubular connector i12 having a cap I'II threaded onto its lower end. The connector Il! and cap Ill cooperate to hold a reservoir or capaule |14 containing a material, such as carbon. dioxide, which when released forms an arc extin guishing duid. The reservoir or capsule Ill is closed or sealed bya diaphragm I'II which is arranged to be ruptured by a pin or needle III carried by a bridge member |11 at the lower end of the ltubular terminal member III. A coil compression spring I'Il reacting between a nut I'Il threaded onto the lower end of the tubular terminal member IIS and the upper side of a dange Ill integrally formed with the connector I'II,` serves to space the pin or needle IIl from the diaphragm Ill until certain predetermined conditions exist at which time the diaphragm Ill is ruptured and the arc extinguishing medium is discharged into the wsageway Ill. v

In operation, when the fusible element I and strain wire Ill are blown, the tubular terminal member ill is released to be moved downwardly under the iniluence ofthe coil compression spring III. The cap Ill is moved downwardly and passes through a frangible diaphragm III, such as micaor transparent plastic. and continues on outside of the tubular terminal member ill to indicate that the device has operated. The iltting III and the attached sleeve Ill continue to move downwardly until the underside of the dtting III engages the upper edge of a stop ring Il! that is secured to the tubular terminal member Ill near its lower end. While further downward movement of the fitting iti is prevented, because of the kinetic energy in the tubular terminal member III, it continues to move downwardly through the iltting IBI and extension Ill until the pin or needle Ill carried by the bridge I'II at its lower end punctures the diaphragm Ill. Further downward movement of the tubu-` lar terminal member Ill is then arrested.

The arc extinguishing fluid released from the |14 is then discharged through the passageway Ill and into the bore III in the solid arc extinguishing material III.

This arc extinguishing iluid assists in extinguishng the arc in the bore il! between the terminal members I and III by sweeping out the vapors incident to the arc and deionizing the are space so as to lessen the likelihood of the arc restriking on the next succeeding half cycle of the alternating current.

Since it is obvious that other embodiments of my invention can be made without departing from the spirit and scope thereof, it ls intended Athat all matter shown in the accompanying drawings and described hereinbefore shall be construed as illustrative and not in a limiting sense.

I claim as my invention:

1. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the fcrm of an arc extinguishing fluid, and means for releasing said fluid when said tubular terminal member reaches a specified position to flow through said opening in said tubular terminal member and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls of said bore.

2. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form of an arc extinguishing iluid, said reservoir being mounted for movement with said tubular terminal member, and means for releasing said fluid when said tubular terminal member reaches a specified position to flow through said opening in said tubular terminal member and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and ,for scavenging the walls of said bore.

3. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other `being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form of an arc extinguishing iluid, means mounting said reservoir for movement with said tubular terminai member and permitting slight relative movement therebetween, and means for releasing said fluid as a result of said relative movement when said tubular terminal member is moved to a predetermined position to ilow through said opening therein and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls of said bore.

4. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a, pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form of an src extinguishing fluid, means mounting said reservoir for movement with said tubular terminal member and permitting slight relative movenient therebetween, a normally extended ilexible bellows hermetically sealing said reservoir to said tubular terminal member, and means for collapsing said bellows and releasing said duid as a result of said relative movement when said tubular terminal member is moved to a predetermined position to flow through said opening therein and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls of said bore.

5. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a .pair of relatively movable terminal members between which an src is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form of an arc extinguishing fluid, means mounting said reservoir endwise in alignment with said tubular terminal member for movement therewith and permitting slight relative movement therebetween. spring means biasing said reservoir away from said tubular terminal member, s normally extended flexible bellows hermetically sealing said reservoir to said tubular terminal member, and means for collapsing said bellows and overcoming the biasing force of said spring means and releasing said fluid as a result of said relative movement when said tubular terminal member is moved to n predetermined position to now through said opening therein and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls of said bore.

6. In circuit interrupting apparatus, in combination a body or arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding msterial which when released is in the form o! on arc extinguishing fluid, releasable means rethining said material in said reservoir, and means for releasing said releassbie means when said tubular terminal member is in a specified position whereby said src extinguishing iluid 1s released to flow through said opening in said tubular terminal member and into the arc space for assisting in extinguishing an src that may exist between said terminal members and for scavenging the walls of said bore.

7. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a pair of relatively movable termina] members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end o! said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form ot an src extinguishing uid, means mounting said reservoir for movement with said tubular terminal member, a rupturable diaphragm sealing said material in said reservoir, and means for rupturing said diaphragm when said tubular terminal member is moved to a predetermined position whereby said arc extinguishing iiuid is released to flow through said opening in said tubular terminal member and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls oi said bore.

8. In circuit interrupting apparatus, in combination a body of are extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and mov- .able through said bore, said tubular terminal,

Vmovement therebetween, and means for rupturing said diaphragm as a result of said relative movement when said tubular terminal member is moved-to a predetermined position whereby said arc extinguishing fluid is released to ow through said opening in said tubular terminal memberv and into the arc space for assisting in extingulshing an arc that may exist between said terminal members and for scavenging the walls of said bore.v

9. In circuit interrupting apparatus, in comblnation a body of arc extinguishing material having a bore, a pair ofrelatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form of an arc extinguishing fluid, means mounting said reservoir for movement with said tubular terminal member and permitting slight relative movement therebetween, a normally extended flexible bellows hermetically sealing said reservoir to said tubular terminal member, and means for collapsing said bellows and rupturing said diaphragm as a result of said relative movement when said tubular terminal member is moved to a predetermined position whereby said arc extinguishing fluid is released to flow through said opening in said tubular terminal member and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls of said bore.

10. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a pair oi relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable' through said bore, said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form of an arc extinguishing fluid, means mounting said reservoir endwise in alignment with said tubular terminal member for movementrtherewith and permitting slight relative movement therebetween, a rupturable diaphragm sealing the end of said reservoir that is adjacent said tubular terminal member, spring means biasing said reservoir away from said tubular terminal member,

a normally extended flexible bellows providingv a hermetically sealed connection between said reservoir and said tubular terminal member,a needle carried by and movable with said tubular terminal member and directed toward said diaphragm, and stop means for arresting movement oi' said reservoir when said tubular terminal member is moved to a predetermined position whereupon said flexible bellows is collapsed, the biasing force of said spring means is overcome and said needle ruptures said diaphragm to release said arcextinguishing fluid to flow through said opening in said tubular terminal member and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls of said bore.

11. In circuit interrupting apparatus, in combination, a body of arc extinguishing material having a bore, a pair of terminals between which an arc may be formed in said bore accompanied by the evolution of an arc extinguishing medium from the walls of said bore and discharge of flame and conducting particles, and means supplementary to said body of arc extinguishing material for cooling and condensing the products of the arc including means providing a restricted passageway at least one wall of which is provided by boric acid.

12. In circuit interrupting apparatus, in combination, a body oi arc extinguishing material having a bore, a pair of terminals between which an arc may be formed in said bore accompanied by the evolution of an arc extinguishing medium from the walls of said bore and discharge of flame and conducting particles, and means supplementary to said body of arc extinguishing material for cooling and condensing the products of the arc including a body of boric acid over the outer surface of which said products are caused tofiow, and an enclosure surrounding said body and providing therewith a restricted passageway to cause said products to come into rintimate contact with said body.

13. In circuit interrupting apparatus, in combination, a pair of line terminal members disposed in insulated spaced relation, a pair of arcingrterminal members between which an arc may be drawn, one arcing terminal member being stationarily mounted and connected to one of said line terminal members and the other arcing terminal member being movable, and means for interconnecting said movable arcing terminal member and the other line terminal member including-main contact finger means which carry,

the major portion of the current between said movable arcing terminal member and said 'other line terminal member before movement of the former is initiated, and auxiliary contact linger means arranged and adapted to carry the current between said movable arcing terminal member and said other arcing terminal member after separation oi said main contact means.

14. In clrcuitinterrupting apparatus, in combination, a pair of line terminal members disposed in insulated spaced relation, a pair of arcing terminal members between which an arc may be drawn, one arcing terminal member being stationarily mounted and connected to one o! said line terminal members and the other arcing terminal member being movable and tubular in character, and means for interconnecting said tubular arclng terminal member and the other line terminal member including main contact 5 means which carry the maior portion o! the current between said tubular terminal member and said other terminal member before movement of the former is initiated, and auxiliary contact means carried by said other terminal member and arranged and adapted to maintain contact engagement with the outer surface of said tubular terminal member as it moves away from said stationary arclng terminal member to extend the are therebetween.

l5. In circuit interrupting apparatus, in oombination, a pair of line terminal members disposed in insulated spaced relation, a pair of arcing terminal members between which an are may be drawn, one arcing terminal member being stationarily mounted and connected to one oi said line terminal members and the other arcrnember being movable and tubular in character and having the end opposite the arcing end enlarged, a plurality of contact fin-- gers by the other line terminal member said. enlarged end portion o! said tubular terminal, and a plurality o! auxiliary. contact lingers carried by said other line terminal member and adapted to engage the body of said tubular terminal member as it moves sway from said stationary arclng terminal member to extend the arc therebetween.

l5. in circuit interrupting apparatus, in com blnation a body of arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one oi said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through said bore, said tubular terminal member having an opening extending longitudinelly therethrough, e. reservoir for holding material which when released is in the form of an are extinguishing fluid, said reservoir being movable together with tubular terminal member, ii oton connection between said reservoir d tubular terminal member whereby relavo movement therebetween is permitted, releasmeting in response to said relative movement between eoid reservoir and said tubular terminal rf robar whereby said aro extinguishing fluid la ed when tubular terminal reaches a li 'ing e bore, pair o relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being tubular in character and movable through bore, tubular terminal member opening extending longitudinally a reservoir for holding material released in the form of an arc uid, said reservoir being movable -h said tubular terminal member, a rineciion between said reservoir and ter member whereby relative 75 movement therebetween is permitted, said ren'b voir and said tubular terminal member being biased apart, means for arresting movement o! said reservoir when it has been moved to a specined position while said tubular terminal member continues to move, releasable means retaining said material in said reservoir, and means for releasing said releasable means in response to said rela- Y tive movement between said reservoir and said tubular terminal member whereby said arc extinguishing duid is released when said tubular terminal reaches a specified position to ilow through said opening in said tubular terminal and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and scavenging the walls of said bore.

18, In circuit interrupting apparatus, in combination1 a housing having a bore, a pair of relatively movable terminal members between which an arc may be formed, one o! said terminal members being located at one end of said -bore and the other being tubular and movable through said bore. said tubular terminal member having an opening extending longitudinally therethrough, operating means for moving said tubular terminal member through said bore, a reservoir for holding material which when released is in the form of an arc extinguishing duid. rupturable means retaining said material 'in said reservoir, means mounting said reservoir for movement with said tubular terminal member and permitting slight relative movement thenbetween, stop means for arresting movement o( said reservoir when the same is moved with said tubular terminal member 'to a predetermined position while said tubular terminal member ycon-- tinues to move, means carried by said tubular terminal member adapted to pierce said rupturable means as a result oi said continued movement of said tubular terminal member for releasing said are extinguishing fluid to flow through said open-y ing in said tubular terminal member and into the arc space, said stop means being manually movable away from its operating position to per- ,r

mit removal of said tubular terminal member, and additional stop means for said operating' means for limiting movement thereof after the nrst mentioned stop means is moved away from its operating position to facilitate removal o( said tubular terminal member.

i9. In circuit interrupting apparatus, a body having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end oi' said bore and the other being tubular in character and movable through said bore. said tubular terminal member having an opening extending longitudinally therethrough, a reservoir for holding material which when released is in the form of an arc extinguishing fluid, said reservoir being mounted for movement with said tubular terminal member, and means for releasing said duid when said tubular terminal member reaches a specied position to now through said opening in said tubular member and into the arc space for assisting in extinguishing an arc that may exist between said terminal members and for scavenging the walls of said bore.

20. In circuit interrupting apparatus, a body having a bore, a pair oi.' relatively movable tefminal members between which an arc is adapted to be formed, one of said members being located adjacent one end of said bore and the other being tubular in character and movable through through, a reservoir mounted `'on said tubular ter- `minal member adjacent one end thereof for said tubular terminal member beother end for discharge thereli of said fluid, and means for releasing laid iluid asa result of relative movement betwedn said tubular terminal member and said reservoir. a

21. In circuit interruptingl apparatus, a body having a bore, a pair of relatively movable terminal members between which an are is adapted to be formed, one of said members being located one end of said borfe and the other becharacter and movable through tubular terminal member having extending longitudinally there- -a reservoir mounted on said tubular terminal member at onelend thereof and yieldingly spaced therefrom with provision for rela- Mve movement of said tubular terminal member toward said reservoir, the latter being disposed in discharge therethrough of said iiuid, and means v'fil' rehasing said rduid as.a result of relative between said tubular terminal member and said reservoir, the latter-being normalLv sealed and containing an arc extinguishing duid under presmember. a reservoir mounted on said member at v one end thereof in substantial alignment therewith to discharge into said one end of said tubular member and yieldingly held spaced therefrom for relative movement of said tubular terminal member toward said reservoir, the latter being normally sealed and containing an arc extinguishing fluid under pressure, the other end of said tubular mem-ber being open for discharge therethrough of said fluid, and means for releasing said fluid as a result of relative movement of said tubular terminal member toward said reservoir.

24. In circuit interrupting apparatus. in combination. a pair of line terminal members disposed in insulated spaced relation, a pair of arcing terminal members between which an arc may be drawn. one arcing terminal member being stationarily mounted and connected to one of said line terminal members and the other arcing terminal member being movable, and means i'or interconnecting said movable arcing terminal member and the other line terminal member including main contact means which carry the major portion of the current between said movable arcing terminal member and said other line terminal member before movement of the former is initiated and spring-biased g auxiliary contact means arranged and adapted to carry the current .between said movable arcing terminal mem-v ber and said other arcins terminal member after separation of said main contact means.

HUGH A. mmm.