US2272717A - Circuit interrupting device - Google Patents

Description

Feb. 10, 1942, L. R. LUDWIG ET AL CIRCUIT INTERRUPTING DEVICE 7 Sheets-Sheet 1 Filed Sept. 19, 1939 Feb. 10, 1942. 1.. R. LUDWIG ET AL CIRCUIT INTERRUPTING DEVICE Sheet 2 Filed Sept. 19, 1959 7 Sheets- 47 INVENT QRS Leon RLUdH/I'g; James/1. in? 25 and Feb, 10; 1942.v L. R. LUDWIG ET AL CIRCUIT INTERRUPTING DEVICE 7 Sheets-Sheet 5 Filed Sept. 19, 1959 7 Sheets-Sheet '7 Frakes. and

fie/d, Admin/s frail/x r/ha M. 56/10 5 fan/ Feb. 10, 1942.. L. R. LUDWIG ETAL CIRCUIT INTERRUPTING DEVICE Filed Sept. 19, 1939 w w M 2 7 a H M w 3 M i..- mw n F 3 7 5 5 l w a a 5 9 5 M 2 3 u a w n m m n 900 Ltd/y, James HINVENTORS Patented Feb. 10, 1942:

cmcmr r'u'raanur'rmc DEVICE Wilkinsburg, and James H.

Leon R. Ludwig,

Frakes, Edgewood, and Stanley T. Schofleld,

deceased. late of Wilkinsburg, Pa., by Martha M. Schofleld, administratrix, Wllkinsburg,

assignors to Westinghouse Electric at Manu- East Pittsburgh, Pa., a

facturing Company, corporation o! Penney lvania Application September 19, 1939, Serial No. 295,590

' (or. Edit-48) 57 Claims.

This invention relates to circuit interrupting devices and more particularly to disconnecting -switches capable of interrupting load currents.

In the transmission of electrical power, the disconnecting switch. heretofore has been used mainly to isolate sections of a transmission line from each other or for isolating a load circuit from its associated network. The switching operation inmostsuch instances necessarily had to be made under conditions of no-load on the circuit being disconnected. Even under conditions of no connected load, the high voltages'now prev alent in transmission practice produce charging currents of appreciable magnitude. Attempts have been made to interrupt line charging currents and light load currents with disconnecting switches equipped with arcing horns. Although certain switches, particularly oi the low-voltage type, have successfully interrupted charging and small load currents, their use for this purpose is unsatisfactory since the exposed are drawn during the circuit opening operation may be blown across the line or to grounded parts thus causing the flow of fault currents.

The main object of our invention is to pro= vide a disconnecting switch capable of interrupting load and charging currents oi a trans mission line without the external display oi an:

Another object of our invention is to provide a circuit interrupting device capable of inter rupting load currents and having a form suitable for movement as a whole into and out of on gagement with at least insert an appropriate air ing circuit interruption.

A further object oi the invention is to provide a load break disconnecting switch wherein a movable blade means for establishing an air break in the circuit completely encloses separable contacts which are actuated to the open circuit position in response to the initial movement of the blade means to the disconnect position.

A more specific object of the invention is to provide a load break disconnecting switch'having separable contacts and an arc extinguishing structure enclosed in a movable blade structure wherein the contacts are actuated to the open circuit position prior to structure out of the connected circuit.

Still another object of the invention is to provide operatingmeans for a load break disconnecting switch of the aforesaid type which sequentially causes the contacts to separateat a speed independently of the speed at which the gap in the circuit follow= movement of the blade one line terminal so as to operating means is moved and then moves the blade structure to the disconnect position.

A further objec" or the invention is to provide a circuit protectivi device embodying two serially related circuit interrupting units capable, respectively, of interrupting load and overload currents. and at least one 01 which is movable out of the circuit for inserting a disconnect gap therein.

It is also an object oi our invention to provide a novel circuit interrupting unit of the enclosed type suitable for operation with disconnect switches oi conventional form for converting such switches to load brealr devices.

Qther objects and advantages will appear more fully in the following description, when taken in connection with the accompanying drawings, in which: i

Figure l is a side view of a load break disconnectihg' switch of our invention showing the movable blade means in longitudinal section;

Fig. 2 is a iront view partially in section of the switch shown in Fig. i;

Fig. 3 is side view showing the switch oi Fig. i in the open circuit position;

his. 4 is side view partially in section of a hoolr StiCliZ operated indoor type load break dis== connecting switch embodying our invention;

Fig. 5 is a fragmentary view partially in section of the upper end of the blade member of the switch shown in Fig. a and is taken at right angles to the position illustrated in that figure;

Fig. 6 is a side view illustrating the circuit interrupter of our invention when used in conjunction with an overload protective device such as fuse;

Fig. 7 is a side view showing another form of load break disconnecting switch embodying our invention;

Fig. 8 is an enlarged sectional view of the circuit interrupting unit of the switch shown in Fig. '7 showing the contacts of the interrupting unit in the closed circuit position;

Fig. 9 illustrates the relative position or the various parts of the interrupting unit of Fig. 8 when that unit is in the open circuit position;

Fig. 10 is an enlarged sectional view of a modiflied form of circuit interrupting'unlt as may be employed in the switch structure shown in Fig. l; and

Fig. ii is a sectional view of the unit of Fig. 10, showing the open-circuit position.

Referring to Figs. 1,2 and 3 oi! the drawings, the reference number It designates a base which carries insulators l5, l1 and I9 disposed in spaced relation with respect to each other, as shown. The free ends of the insulators l1 and H are joined by a conducting support member 2|. The support member 2| carries a pair of spaced brackets 23 having a cross shaft 25 extending therebetween adjacent their outer ends. Journalled for pivotal movement on the shaft 25 is a casing 21 of conducting material which carries a hollow blade member generally indicated at 29. The blade member 29 comprises a tubular member 3| of insulating material screw threaded onto a metallic sleeve 33. The sleeve 33 extends through a suitable aperture into thecasing 21 and has a threaded collar 35 which secures per-- tions of the upper wall of the casing against the tubular member 3|.

A tubular conducting member W is concern trically disposed within the insulating member 3i and makes contacting engagement at its lower end with the tubular member 33. The upper end of the member 31 has a flanged portion 39 which serves as one of the contacts within the tubular blade member M. A sleeve of insulating material 4| surrounds the tubularconducting member ll so as to provide an annular arc passage 43, the outer wall of which is defined by the tubular insulating member at. ".lThe lower end of the arc passage 43 is closed by an annular member B5 oi insulating material abutting the conducting sleeve 33. .Secured to the upper end of the insulating tube 31 is a tubular cap member All of conducting material. Surrounding the cap mem ber 41 is a comically shaped sleeve t9 also of corn ducting material which projects downwardly so as to overlap the upper end portion oi the insulating member 3 l sleeve id carries at least two inwardly projecting diametrically-opposed contact segments 5i, (Fig. 2) which project through suit able apertures formed in the members ill and ti. Normally disposed between the contact segments 5! and the contact portion 39 is a movable contact ring 53 carried by the lower end oi? a mov able tubular barrier member 55 of insulating material. The barrier member 55 is closed at its upper end by the member bl to which is secured an operating rod 59 having sliding movement through the tubular conducting member ill. The lower end of the operating rod 59 has secured thereto a disc 6|. A compression spring 63, one end of which bears against the upper end of the metallic sleeve 33 and the other end against the disc 8|, biases the operating rod 59 downwardly so as to move the barrier member 55 and its associated contact 53 into the arc passage ill. The contact 39 and the contact segments bl are provided with grooves tit and B3 so as to confine arcing," to the lower portions thereoi thereby preserving the upper portions against the erosive efiects of the arc. Movement of the operating rod 59 is normally prevented by means of a latch pivotally' carried by the sleeve 35. The

till

tilt

method of releasing the latch 65 for the purpose of separating the contacts within the blade member 29 will appear more fully hereinafter.

The insulator l5 carries a terminal member 5'! having two outwardly extending supports 69 thereon. Pivoted to the supports 53 and having limited swinging movement therewith are a pair of arms H. The free ends of the arms ll support a U-shaped contact yoke 13 which is also mounted for limited pivotal movement with respect to the arms. The contact yoke 13 has an inner contact receiving surface which tapers in- 75.

wardly in the upward direction and is adapted to receive the conical sleeve portion 49 of the blade member 29. A spring '15 tends to cause arms H to rotate in a counter-clockwise dlrection as viewed in Figs. 1 and 3, about their pivotal supports. The spring 11 in a similar manner biases the contact yoke 13 for clockwise rotation about its pivotal support at the ends of the arms H. The purpose of this particular construction will appear more fully hereinafter.

When the blade member 29 is in the position shown in Fig. 1, the conical sleeve 49 is tightly wedged into the contact yoke 13 so that the contact segments 5i exert a high pressure against the moving contact 53 which, in turn, malzes high pressure contact with the fixed contact portion Flexibility within the conical sleeve 49 is attained by slotting the left hand side thereof, as more clearly shown at "ill in Fig. 1. The contact ring 63 is also preferably slotted to impart ilexlbility thereto and thereby permit the abovementioned high pressure contact action. Thus the circuit through the interrupter proceeds from the terminal 551, shunt Bl to the contact yoke 13, contacts ill, 53, 3t, conducting member ill, conducting sleeve till, casing ill, shunt support 2|, and finally terminates with a line terminal B3 secured to the support member ill.

In order to operate the blade member it to the open and closed position, the insulator i5 is mounted ior rotativc movement with respect to the base ill and is journaled at its free end in the conducting support plate ill. lilecured to the outer end of the insulator ill "is an operating arm oil having an operating linlii ll'l coupled thereto, by a universal joi The other end of the operating link 8"! is pivotally coupled in a like manner to a boss Ill secured to the side oi the casing as more clearly shown in Fig. it. it will thus be seen that since the casing is pivotally mounted upon the cross shai't iii, rotation of insulator ill in the clockwise direction, as viewed in it, will cause the link. 8'! to rotate the casing ill about the cross shaft 25 and in a clocltwise direction to the peeltion shown in Fig. 3. The cross shaft it is ilxedly secured to the brackets it so as to prevent rotation thereoi with respect to the bracltets. Fixedly secured to the cross shaft ill and disposed in a hm-mental direction, as shown in li ies. l and 3,

is an actuating arm ill. lfloupled to the free end of the arm Si is an actuating llnlr the other end oil" which is pivotally connected to the intermediate portion oi an operating lever The operating lever is pivoted at ill to the casing Ti and has its free end provided with an abutment 9!).

From the relation of the parts shown in Fig. i, it will be observed that as the casing ill and the tube 25 begin to rotate in a cloclrwise direction, the latch lit through. pivoted trigger member llll engages the operating arm Si, thus rotating the latch 65 in a clockwise direction to release the disc 6i, thereby permitting the spring 63 to actuate the operating rod 59 downwardly carrying with it the movable contact ring 53 and the insulating barrier 55. An arc will be drawn in the arc passage 43 which is confined to the narrow clearances between the three concentric tubes 3!, 55 and 4|. Although contact 53 is subjected to relatively high lateral pressure when engaged, spring 63 is strong enough to cause longitudinal sliding of contact 53 when latch 55 is released. The concentric tubular members 3|, 4! and 55 are preferably constructed of insulating material which evolves considerable gas when acted upon by an arc to aid in extinguishing the are, for example, hard fiber has been found a suitable material for this purpose. As thebarrier member 55 moves into the annular arc passage til, the arc gases are driven through the arc stream and ment a blade member generallycindicated at I ll. The blade member II I comprises a tubular member H3 of insulating material secured at its lowmust escape to the space provided within the enclosed cap member ill. This metallic cap member ll serves as a condenser for the arc gases escaping from the space between the barrier '55 and the tubular member 33. Inasmuch as the operating rod til permits some gas to escape therealong through the tubular conductor 3'5 into the casing 27, the latter also serves as a completely enclosed condensing chamber.

Tripping of the latch @355 causes the contacts to open within the blade member 293 at a high speed which is independent of the speed of movement oi the actuating insulator B9. In ia'ct, the contacts within the blade member 2d are moved to the open circuit position and the arc is extin guished prior to separation of the conical sleeve it from the contact yoke Contact between blade member 29 and the yoke it continues dur ing the initial opening movement of the blade member is by virtue of the pivotal linkage ll supporting the contact yoke it. Thus the yoke er end to a metallic ferrule Ill. The ferrule ill has a metallic sleeve H9 extending upwardly into the insulating tube lit and is joined with a me? tallic collar i211 which, in turn, supports a tubular conducting member M3, the upper end of i which has a contact portion 62b. The tubular ill conducting member B23 is surrounded by a tubular sleeve lZll of insulating material so asto form an annular arc passage 629 similar to the are passage 83 previously, described in connection with Figs. 1 to a it remains in contact with the sleeve 39 until the yoke reachesthe position shown in Fi 3.

It will thus be seen that the circuit is completely a interrupted within the blade member is prior to disengagement oi the member from the contact yoke When the operating rod 59 reaches its full open position, it bears against the abutment 99 of the operating lever 95. As the blade member is rotated to the open circuit position, the connecting link t3 causes the operating lever to move the operating rod 59 inwardly with respect to the blade 29 until the disc til is again engaged by the l latch. 55, thereby relatching the-contacts within the blade member in the closed circuit position at such time when the blade member reaches its iull= open position, as shown more clearly in Fig. 3. As the blade member 2% is again brought to the closed circuit position by rotation of the insulator it in the counter-clockwise direction, as viewed in Fig. 2, the conical sleeve 59 engages the contact yoke l'ii while the latter is in the position shown in Fig. 3.

It will be apparent that continued rotation of the blade 29 in a counter-clockwise direction, as viewed in. either Fig. l or 3, will cause movement of the yoke l3 downwardly with respect to the sleeve 49, thereby securing a high pressure wiping contact which also exerts a high pressure on the inner contacts 5!, 53 and 351?. As the blade member 29 moves into its final closed circuit povsition, the latch 65 clears the actuating arm 9i because the trigger member IN .is pivotally mounted upon the latch 65 for rotative movement in the counter-clockwise direction and is biased for rotation in the clockwise direction against a suitable stop, as shown in Fig. l. The

conductor A rnetallic closure cap i3i closes the end of the tube lit. Surrounding the lower end'of cap 935 and also overlapping the end of. the in sulating tube M3 is a metallic sleeve member having a pair of blade members till, only one oil which is shown, adapted to engage oppos sides of a single blade terminal carried by the insulator M95. The cap 630 has an con" tact portion E39 disposed at the lower end there of opposite the contact portion oi the tubular an annular movable contact Edi is normally positioned in bridging relation with respect to the contacts 1125 and ried by the lower end of a movable barrier her 1630f insulating material. The upper end of the barrier t lt is closed by a threaded plug i l-5 to which is secured the upper end of an operating rod t ll.

The operating rod Ml extends downwardly through the tubular conductor and is provided at its lower end with a disc Mil. Disposed between the disc its and the tubular conductor is a spring 55H for moving the contact Edi and the barrier M3 into the arc, chamber The contact H ll and the barrier M3 are normally held against movement by the spring Hit by a movable latch member Q53 engaging a latch pin extending transversely of the cap member When the switch is in the position shown in Fig. 4, the circuit thereto proceeds through the terminal member Hi, the blade 11 sleeve lilfi, cap member 53H, contacts 839, Nil, Nil, tubular conductor i253, collar lZl, sleeve Mil, ferrule ill to the lower terminal member lbs. The blade member ill is held in the closed circuit position against accidental opening by heavy currents flowing therethrough by means of a latch lever 15?, pivoted to the closure cap Hill at lfiil. The left hand end of the latch lever lEil engages a catch it! forming an upward extension of the terminal 931. The latch lever ital has two branches extending oneon each side of the closure cap I35 which unite on thegright hand side thereof and terminate in a loop I63, which serves as a-means for engaging the customary hook stick ,for operating the blade member ill to open and closed circuit positions. The latching lever I5! is also pivotally connected by a pair of upstanding links I65 to a transversely extending. release bar Nil. The release bar is adapted to slidably operate. in slots I69 provided 'on diametrically opposite sides of the cap IM I6I and also actuates the links I55 downwardly causing the release bar I61 to engage the upper cam surface I13 of the latch I53, forcing the latch I53 to the left, out of engagement with the bar I55, thereby releasing the operating rod I41, whereupon the spring II actuates the movable contact HI and the barrier I43 downwardly into the arc chamber I29. The are thus drawn in the confined annular spaces on either side of the barrier member I43 is quickly extinguished in the manner previously described in connection with the structures shown in Figs. 1 to 3.

Upon the release of the moving contact memher I by the downward movement of the loop I93 and also the simultaneous release of the latch lever I51 from the catch IBI, it is apparent that an outward movement of the loop I63 will cause the blade member III to be rocked about its lower pivotal support to the open circuit position. In the open circuit posi tion the disc I49 secured to the lower end of the operating rod I41 rests against a similar disc I15 secured to the upper end of a rod I11 extending through the lower end of the ferrule H1. The lower end of the rod I11 is connected by a link I19 to a fixed bracket arm I8I mounted upon the contact terminal I09 carried by the insulator I01. The bracket I8I, the linkage I19 and the rod I11 are so arranged with respect to the blade member III that upon movement of the latter to the full open circuit position, the rod I11 is moved inwardly with respect to the blade member III to cause the operating rod I41 to be moved to the closed circuit position so that the pivotal latch I53 again is forced to engage the bar I55, thus reseating the contacts within the blade member III for a subsequent circuit opening operation.

In Fig. 6 we have shown a circuit interrupting structure embodying the principles heretofore described in .conjunction with an overload protective device which also serves to function as a circuit disconnect. In Fig. 6, a base I83 carries three insulators I85, I81 and I89. Mounted upon the insulator I85 is a line terminal member I9I having a contact clip I93 which engages the upper end of a fuse I95 which may be of the type shown in H. L. Rawlins Patent No. 1,976,634, issued October 9, 1934. The fuse I95 is pivotally mounted at its lower end to a bracket extension I91 carried by a terminal I99 supported upon the insulator I81. The terminal I99 also has a yoke-like member 20I embracing the'upper end of a circuit interrupting unit 203; The lower end of the interrupting unit 203 is secured to, and supported by, a conducting terminal 205 carried by the insulator I89. It will be noted that the interrupting unit 203 in this instance is similar in construction to the blade member III shown in Fig. 4, except that the operating rod 201, which corresponds to the rod I41 in Fig. 4, is provided with a roller type catch 209 which is adapted to engage a latching lever 2I I, which is pivoted at its upper end to the side of the ferrule 2I3 of the interrupting unit 203. The operating rod 201 also has a lower extension which terminates in a loop 2I5 for the insertion of a hook stick to render the rod manually operable.

The circuit through the protective device, as shown in Fig. 6, proceeds from the terminal I9I through the fuse tube I95, the bracket I91, terminal I99, interrupting unit 203, to the terminal 205. To interrupt the circuit while carrying normal load currents, it is necessary to actuate the latch lever 2 to release the operating rod 201. This is accomplished by a lever 2I1 pivoted at 2I9 to a bracket 22I secured to the base I83. The right-hand end of lever 2I1 has a roller 223 normally engaging the lower side of the latch lever 2II. The left hand end of the lever 2I1 has an offset portion 225 adapted to be engaged by a roller 221 journalled in an actuating lever 229 which is also pivotally mounted at 23I to the bracket 22I. The actuating lever 229 is provided with an operating ring or loop 233 into which a hook stick may be inserted for moving the lever 229 downwardly, thus rocking the lever 2I1 in the counterclockwise direction, causing the roller 223 to engage the latch lever 2I I, raising the same to release the roller 209 and thus permit the operating rod 201 to be moved to the open circuit position. Closing of the contacts within the circuit interrupter 203 is accomplished by inserting a hook stick in the loop 2I5 and forcing the rod upwardly until the latch 2II again engages the roller 209.

When the circuit through the interrupter 203 has been opened in the manner described, the fuse tube I95 may be swung about its lower pivotal support by the insertion of a hook stick in its operating ring 235 in the usual manner. In the event that an overload occurs in the circuit, the fuse I95 blows and interrupts the circuit, thereby also providing overload protection. It is thus seen that by this simple arrangement of mounting the fuse structure I95 and the circuit interrupting device 203 upon three insulators, one of which serves as a common support for the two interrupting units, economy in mounting structure is obtained and a protective device is provided which serves to interrupt the circuit on both load and overload currents. In addition, means are provided for placing an appreciable air gap in the circuit for isolating the load circuit from the transmission line without providing for movably mounting the load break device.

In Fig. "I a circuit interrupting unit embodying the ieatures of our invention is shown applied to a more or less conventional disconnect switch. The disconnect switch shown in Fig. '1 is fully shown and described in H. J. Crabbs Patent No. 2,067,659, issued January 12, 1937, and assigned to the assignee of the instant application. As set forth in the above-named patout, the disconnect switch proper comprises a base I upon which are mounted three spaced insulators 243, 245 and 241. The insulators 245 and 241 are joined by a conducting support plate 249, to which one terminal of the switch is connected. The insulator 245 also carries a pair of upstanding brackets 25I, only one of which is shown and to whichis pivotally mounted for swinging movement a blade member 253. A second blade member 255, joined near its outer end to the blade member 253 by a pair of links 251, is connected at its other end to a link 259, which, in turn, joins the pivotal axis of the blade 253. The insulator 241 is mounted for rotative movement and has an actuating arm 26I secured thereto which is universally connected by means of an operating link 283 to the pivotal connection of blade 255 and arm 259. The free ends of the blades 253 and 255 are adapted to be engaged by a U-shaped conprior to the introduction of an air gap in the circuit, which contacts are completely enclosed tions.

also serves as a condenser for condensing the portion m of the latch m engages the cam surface 333 at the lower end of the slot 332 so as to force the latch m to the left after the movable contact 293 has been brought in registration with the contacts 233 and 293. The contact structure, therefore, is again in the closed circuit position in readiness for a subsequent opening operation.

Fig. 10 illustrates another form of circuit interrupting unit which is similar to the unit shown in Fig. 8, except that the support rod 333 has been replaced by a support rod 321 of uniform cross section. Surrounding the support rod 321i is a tubular operating member 329, theupper end of which makes a swivel connection at 33l with the upper end of the movable barrier member 29!. The operating member 329 is also provided with a pair of diametrically opposed helical slots 333 into which the opposite ends of a guide pin as extend. The guide pin :35 is held fixed with respect to the support rod 321 and is mounted at the upper end thereof by a screw 331. The lower end of the operating member 329 has an inwardly extending flange 339 for engaging one end of a compression spring 341 surrounding the rod 321. The other end of the spring 3 presses against the support for the guide pin 335. It will thus be seen that the spring 3 tends to urge the operating member 323 downwardly carrying with it the barrier member 295 and the moving contact 293.

Movement of the operating member 329 is prevented by a bayonet latch 343 secured to the upper end of the operating member 329 which engages two inwardly extending spring pressed catch members 345. Thus when the interrupting unit is moved as a whole during the switch opening operation as previously described with respect to the support rod 321, and against the compression of spring 341, the operating member 329 will be rotated about its longitudinal axis with respect to the catch members 345. The pitch of the helical slots 333 is so chosen that the operating member 329 and the bayonet latch 343 will have rotated substantially 90 when compression oi the spring 3 is complete. When the bayonet latch 343 has rotated 90 from the position shown in Fig. 10, it will be released from the catch members 345, thus permitting the barrier member 295 to move the movable contact 293' out of engagement with the contacts 283 and 239 to the position shown in Fig. 11. The are thus drawn in the arc chamber 219 is quickly extinguished in the manner previously described.

Resetting of the contacts to the closed position during the closing stroke of the switch is similar to that described in connection with Figs. 8 and 9 except that the movement of the interrupting unit in this instance towards the support bracket 21! causes the bayonet latch member 343 to be forced between the catch members 345, which are spring pressed and spread to permit the enlarged portion of the latch member to pass therethrough. The catch members thereafter spring back in place to relatch the contacts in the closed circuit position.

It will be noted that the circuit interrupting units described in Figs. 8 through 11 embody a contact structure for interrupting the circuit and protected from exposure to climatic condi- The metallic cap or closure member 285 generated gas during the circuit opening operation, and prevents the existence of external arc or flame.

Although we have shown and described several specific embodiments'of our invention, it is to be understood that the sam were for the purpose of illustration and that changes and modiflcations may be made by those skilled in the art without departing from th spirit and scope oi the appended claims.

W claim as our invention:

1. In a circuit interrupter, a pair of concentric tubes of insulating material defining an annular arc passage, separable contact means for drawing an are adjacent one end of said are passage, and a third tube of insulating material relatively movable between said pair of concentric tubes for causing said are to be restricted in cross section and lengthened along a path substantially twice the length of the relative movement between said last-named tube and said pair of concentric tubes.

2. In a circuit interrupter, a pair of concentric tubes of insulating material defining an annular arc passage, separable contact means for drawing an arc adjacent-one end of said are passage,

- and a third tube of insulating material normally disposed outside said arc passage and biased for movement into said are passage upon formation of an are between said separable contacts, said third tube of insulating material being dimensioned to substantially fill said arc passage" when moved therein for confining the arc to the restricted clearances between said tubes.

3. In a circuit interrupter, a. pair of concentric tubes of insulating material defining an annular arc passage, a pair of stationary contacts disposed adjacent one end of said pair of concentric tubes, a bridging contact normally coacting with said pair of stationary contacts to complete the electric circuit therebetween, means for moving said bridging contact into said arc passage to establish an arc therein, and a tubular follower of insulating material movable into said are passage for causing the arc to play in two series related branches one in each of the annular spaces between said follower and said concentric tubes.

4. In a circuit interrupter, a pair of concentric tubes of insulating material defining an annular arc passage, a pair of stationary contacts disposed adjacent one end of said pair of concentric tubes, a third tube of insulating material movable between said stationary contacts into said arc passage, a movable contact carried by said third tube normally bridging said stationary contacts when said third tube is outside said are passage, and means for moving said third tube into said are passage to cause said movable contact to draw an arc with each of said stationary contacts.

5. Ina circuit interrupter, means of insulating material defining an annular arc passage open at one end and closed at the other end, separable contact means adjacent the open end of said arc passage, a tubular member of insulating material open at one end and closed at the other end, said tubular member being normally disposed with its open nd adjacent to the open end of said are passage and in alignment with said pasnals.

asvaviv sngaineans ior actuating said separable contact means to establish an arc across the open end oi said are passage, and means ior moving said tubular member into the arc passag to confine the are between the walls of said tubular mom contacts into engagement with said movable con-= tact member and the other oi said spaced con= tacts to provide a low resistance connection between said contacts and said contact member.

'7; a circuit interrupter, means of insulating mate ial defining an annular arc passage, a pair oi generally annular and concentrically disposed,

spaced contacts adjacent one end of said are passage, a tubular member of insulating material movable between said spaced contacts into said.

are passage, and a tubular contact carried by one end of said tubular member and normally adapted to interconnect said spaced contacts,

each of said spaced contacts having an annular groove intermediate its ends for confining arcing between said spaced contacts and said tubular contact to a portion of the contact surface on one side of said groove.

8. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least on of said terminals, said bridging means including means of insulating material defining an annular arc passage, separable contact means adjacent one end of said are passage movable to open and closed circuit positions for interrupting and establishing a circuit between said terminals while said bridging means is in engagement with said terminals, a tubular member of insulating material movable into said are passage upon sop- F tricallv connecting said terminals and movable into and out of engagement with at least one oi said terminals, said bridging means including means of insulating material defining an annu= lar arc passagebeparable contact means edja= cent one end of said are passage movable to open and closed circuit positions for interrupting and establishing a circuit between said terminals while said bridging means is in engagement with said terminals, spring means, a tubular member of insulating material movable into said are passage by said spring means to cause separation of said contact means, latch means normally holding said tubular member against the bias oi said spring means, and operating means operabl in one continuous movement for first releasing said latch means to cause said spring means to move said tubular member and contact means to the open circuit position and for thereafter mov hi said bridging means out of engagement with at least on of said terminals. V

lhln a circuit interrupting device, a pair of spaced terminals, bridging means normally elec,

iii

tricallv connecting said terminals and movable into and out oi engagement with at least one of said terminals, said bridging means including means of insulating material defining an anion oration of said contact means, and operating means operable in one continuous movement for first separating said contacts to establish an arc and to cause said tubular member to be moved "into said are passage to extinguish the arc and.

for thereafter moving said bridging means out of engagement with at least one of said termi= 9. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least one of said terminals, said bridging means including means of insulating material'defining an annular arc passage, having astationary contact adjacent one end thereof, a coacting contact movable into said arc passage for establishing an arc therein while said bridging means is in engagerlment with said terminals, a tubular follower of insulating material movable into said arc passage to assist f are extinction, and operating means operable in one continuous movement for first causing said movable contact and said follower to be moved into said are passage and thereafter for moving said bridging means out of ngagement with at least one of said terminals.v

lar arc passage, separable contact means adja cent one end of said are passage movable to open and closed circuit positions for interrupting and establishing a circuit between said terminals while said bridging means is in engagement with said terminals, spring means biasing said contact means to the open circuit position, latch means normally holding said contact means in the closed position against the bias of said spring means, a tubular member of insulating material movable into said are passage by said spring means upon separation of said contact means, and operating means operable in one continuous movement for first releasing said latch means to cause said spring means to move said contact means and said follower to the open circuit position and for thereafter moving said bridging means out of engagement with at least one of said terminals, and means operable in response to movement of said bridging means for moving said separable contact means and said follower to the closed circuit position.

12. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least one of said terminals, said bridging means including separable contact means, spring means for actuating said contact means to the open circuit means out of engagement with at least one of i said terminals.

13. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electries-11y connecting said terminals and movable into and out of engagement with at least one of said terminals, said bridging means including separable contact means, spring means for actuat ng said contact means to the open circuit position, latch means restraining the action of said spring means, and operating means operable in one continuous movement for first releasing said latch meansto cause said spring means to move saidcontact means to the open'circuit position and for thereafter moving said bridging means ut of engagement with at least one of said ter inals, and means operable in response to movement of said bridging means for moving said separable contact means to the closed circult position.

'14. In a circuit interrupting device, a pair of spaced terminals, bridging-means normally electrically connecting said terminals and movable into and out of engagement with at least one of said terminals, said one terminal having limited movement with said bridging means during the initial movement of said bridging means towards the open circuit position, said bridging means including separable contact means, spring means biasing said contact means to the open circuit position, latch means holding said contact means in the closed position against the bias or said spring means, operating means for operating said bridging means out of engagement with at least said one terminal, and means actuated by said operating means during the limited movement saidw oone terminal with said bridging means tor releasing said latch means to cause said spring means to move said contact means to the open circuit position. A

15. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least on of I ,said terminals, said one terminal having limited movement with said bridging means during the initial movement of said bridging means towards the open circuit position, said bridging means including separable contact means, spring means ducting member on each end thereof adapted to engage said spaced terminals, said bridging member being movable into and out of engagement with at least one of said terminals, conbiasing said contact means to the open circuit position, latch means holding said contact means in the closed position against the bias of said spring means, operating means for operating said bridging means out of engagement with at least said one terminal, and means actuated by i said operating means during the limited movement of said one terminal with said bridging means for releasing said latch-means to cause said spring means to move said contact means to the open circuit position, and means operable in response to movement of said bridging means following disengagement or the latter from said one terminal for relatching said contact means in the closed circuit position.

16. In a circuit interrupter, a pair of spaced terminals, a hollow bridging member at least partialiy of insulating material and having a conducting member on each end thereof adapted to engage said spaced terminals, said bridging member being movable into and out of engagement with at least one of said terminals, conductingmeans within said bridging member electrically connecting said conducting members, said conducting means including separable contact means, means biasing said contact means to the open circuit position, latch means for normally holding said contact means in the closed circuit position against the action 0! said biasing means, and operating means operable in one continuous movement for first tripping said latch means to cause separation of said contact means ducting means within said bridging member electrically connecting said conducting members, said conducting means including separable contact means, means biasing said contact means to the open circuit position, latch means for normally holding said contact means in the closed circuit position against the action of said biasing means, and operating means operable in one continuous movement for first tripping said latch means to cause separation of said contact means to draw an are within said hollow bridging member and for thereafter moving said bridging member out of engagement with at least one of said terminals, and means operable in response to movement of said bridging memher out of engagement with said one terminal for relatchlng said separable contact means in the closed circuit, position.

18. In a circuit interrupter, a pair of spaced terminals, bridging means including a casing movably mounted on one of said terminals, a hollow blade member at least partially of insulating material extending from said casing, a conducting member carried by the free end of said blade member adapted to be moved into and out of engagement with the other terminal in accordance with movement of said casing, conducting means including separable contact means within said bridging means connecting said conducting member andsaid casing, a spring biased actuating member extending into said casing for moving said contact means to the open circuit position, latch means for said actuating member to hold said separable contact means in the closed circuit position, operating means for said casing operable to move said blade member out of engagement with said other terminal, and actuating means within said casing operable during the initial movement of said casing to trip said latch means to cause said actuating member to move said contact means to the open circuit position.

19. In a circuit interrupter, a pair of spaced terminals; bridging means including a casing movably mountedon one of said terminals, a hollow blade member at least partially of insulating material extending from said casing, a conducting member carried by the free end oi said blade member adapted to be moved into and out of engagement with the other terminal in accordancewlth movement of said casing, conducting means including separable contact means within said bridging means connecting said conducting member and said casing, a spring biased actuating member extending into said casing for moving said contact means to the open circuit position, latch means for said actuating member to hold said separable contact means in the closed circuit position, operating means for said casing operable to move said blade member out of engagement with said other terminal, and actuating means within said casing i operable during the initial movement of said casto draw an are within said hollow bridging memtially of insulating material and having a coning to trip said latch means to cause said actuating member to move said contact means to the open circuit position, and means within said casing operative upon further movement of said casing for moving said actuating member to its latched position.

20. In a circuit interrupter, a terminal, a hollow blade member at least partially of insulat- I ing material mounted for swinging movement,

a contact, an off-set support for pivotally mounting said contact on said terminal, a contact member on the free end of said blade member adapted to be moved into and out-of engagement with said pivotallysupported contact, said support being arranged to provide a limited amount of movement of said pivotally mounted contact with said blade member during the initial movement of said blade member to the open circuit position, separable contacts within said hollow blade member biased to the open circuit position but normally latched in the closed circuit position to complete the electric circuit to said terminal when said blade member is in the closed circuit position, operating means for swinging said blade member to the open circuit position, and means operative in response to the initial movement of said blade member to the open circuit position for separating said separable contacts to interrupt the circuit.

21. In a circuit interrupter, a pair of spaced terminals, a hollow blade member mounted for swinging movement to open and closed positions on one of said terminals, said blade member having a yielding contact portion adjacent to the free end thereof, a contact member movably mounted on the other terminal for receiving said yielding contact portion when said blade member is in the closed position, a movable contact within said hollow blade member adapted to coact with said yielding contact portion to establish a circuit between said terminals when said blade member is in the closed position, and support means for said contact member having limited relative movement with respect to said other terminal and said blade member operative to cause a high pressure engagement between said contact member, said yielding contact portion and said movable contact when said blade member is moved to the closed circuit position.

22. In a circuit interrupter, a pairof spaced terminals, a hollow blade member mounted for swinging movement to open and closed positions on one of said terminals, said blade member having a yielding wedge shaped contact portion adjacent the free end thereof, a contact yoke adapted to coact with said contact portion on.

said blade member, a support for movably mounting said contact yoke on the other terminal, a movable contact within said hollow blade member adapted to coact with said yieldingv contact portion to complete the circuit between said terminals when said blade member is in the closed circuit position, and operating means for swinging said blade member to open and closed positions, said support providing lim.- ited swinging movement of said contact yoke with said blade member and limited relative movement longitudinally of said blade member during the final closingmovement of said blade.

one of said terminals for swinging movement into ing to actuate said contacts to the open circuit position to establish an arc, means wholly within said casing for extinguishing said arc, and operating means operable in one continuous movement for first releasing said actuating means to separate said contacts, and for thereafter moving said casing out of engagement with respect to said other of said terminals.

24. In a circuit interrupting device, a pair 01' spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least one of said terminals, means latching said bridging means to said one terminal to normally hold said bridging means in the closed circuit position, sepable contacts carried by said bridging means biased to open circuit position, means for latching said separable contacts in the closed circuit position, and operating means operable for first unlatching said separable contact latching means and then unlatching said bridging means from said one terminal to permit the bridging means to be moved out of engagement with said one terminal. Z5

mounted on one of said terminals for swinging movement into and out of engagement with the other of said terminals, an engageable latching .lever pivotally mounted adjacent the free end of said bridging member for normally holding said bridging member in the closed circuit position, separable contacts within said bridging member biased to the open circuit position, means for latching said separable contacts in the closed circuit position, and means actuated by movement of said latching lever torelease said separable contact latching means to cause said contacts to interrupt the circuit prior to movement of said bridging means out of engagement with said other terminal.

26. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least one of said terminals, means latching said bridging means to said one terminal to normally hold said bridging means in the closed circuit position, separable contacts carried by said bridging means biased to open circuit position, means for latching said separable contacts in the closed circuit position, and operating means operable for first unlatching said separable contact latching means and then unlatching said bridging means from said one terminal to permit the bridging means to be moved out of engagement with said one terminal, and means operable in response to movement of said bridging means to the'open position for latching said separabl contacts in the closed circuit position.

2'7. In a circuit interrupter, a pair of spaced terminals, a hollow bridging member pivotally mounted on one of said terminals for swinging movement into and out of engagement with the other of said terminals, an engageable latching lever pivotally mounted adjacent the free end of said bridging member for normally holding said bridging member in the closed circuit position, separable contacts within said bridging member biased to the open circuit position, means for latching said separable contacts in the closed circuit position, and means actuated by movement of said latching lever to release said separable contact latching means to cause said contacts to interrupt the circuit prior to mo'vementoi said bridging means out of engagement with said other terminal. and means activated by movement 01' said bridging member to the open circuit position relatching said separable contacts in the closed circuit position.

28. A switching device comprising a pair of spaced insulators, a terminal supported on each of said insulators, bridging means including fusible means pivotally mounted on one of said terminals for swinging movement into and out of engagement with said other terminal for making and breaking the electrical circuit between said terminals, a third terminal insulatingly supported in spaced relation with said pair of terminals, and circuit interrupting means including a pair of separable contacts disposed between said third terminal and one of said pair of terminals, means for separating said contacts while said circuit interrupting means is in engagement with its respective terminals, said one oi! said pair oi terminals serving as a common support for said fusible means and said circuit interrupting means. V 29. Circuit interrupting means comprising three spaced conducting terminals, a circuit interrupting device movably supported between two of said terminals, said circuit interrupting device being adapted to interrupt overload currents while in engagement with said two terminals and being movable out of engagement with at least one of said terminals to insert an air gap of appreciable length in the circuit, and a second circuit interrupting device connected in series with said first circuit interrupting device and supported between two of said terminals one of which is common to both interrupting devices, said second interrupting device having separable contacts adapted to interrupt load currents of lesser magnitude than the overload current interrupted by said first circuit interrupting device, and means for separating said contacts while said second circuit interrupting means is in engagement with its respective terminals.

30. The combination with a switch having a terminal member and blade means operable into and out of engagement with said terminal member of an arc extinguishing device having a casing supported for limited relative movement with respect to said terminal member, said casing having an external contact terminal engageable by said blade means at least during the initial open-- ing movement thereof, separable contacts within said casing connected for establishing a circuit through said casing from said terminal member to said blade means, means for actuating said blade means to open circuit position, said separable contacts being movable with said casing for maintaining the circuit therethrough until said blade means has ben moved out of engagement with said terminal member, and means responsive to further movement of said casing 'by said blade means to cause said separable ontacts to open and interrupt the circuit.

31. The combination with a switch having a terminal member and blade means operable into and out oi engagement with said terminal member of an arc extinguishing device having a casing supported for limited relative movement with respect to said terminal member, an electrical circuit through said casing including separable contacts at least one of which is connected to said terminal member, means for releasably connecting said blade means with another of said separable contacts to establish a circuit in parallel with the gap formed between said terminal member and said blade means, said connecting means including means for moving said casing relative to said terminal member, and means responsive to predetermined movement oi said casing following disengagement of said blade means from said terminal member to cause said contacts to separate and interrupt the circuit.

'32. The combination with a switch having a terminal member and blade means operable into and out of engagement with said terminal member of an arc extinguishing device having a casing supported for limited relative movement with respect to said terminal member, an electrical circuit through said casing including separable contacts at least one of which is connected to said terminal member, means for releasably connecting said blade means with another of said separable contacts to establish a ircuit in parallel with the gap formed between said terminal member and saidblade means, said connecting means including means for moving said casing relative to said terminal member, means biasing said separable contacts to the open circuit position, latch means for normally holding said separable contacts in the closed position, and means responsive to a predetermined movement of said casing for tripping said latch means to cause said contacts to separate with a quick action.

33. The combination with a switch having a terminal member and blade means operable into and out of engagement with said terminal member oi an arc extinguishingdevice having a casing, a circuit through said casing including separable contacts at least one of which is connected to said terminal member, means for releasably connecting said blade means with another of said separable contacts to establish a circuit in parallel with the gap formed between said terminal member and said blade means, means biasing said separable contacts to the open circuit position, means normally holding said contacts in the closed position, an operating member disposed for relative movement with respect to said casing for controlling said holding means, said connecting means including means operative to produce relative movement between said operating member and said casing at least following disengagement oi said blade means from said terminal member to cause said holding means to release said separable contacts only following disengagement of said blade means from said terminal members.

34. In a circuit interrupter, arc extinguishing means including separable contacts normally held in the closed circuit position, means of insulating material movable to a position between said contacts, biasing means for actuating said contacts to the open circuit position and said insulating means to said position between said contacts, operating means for moving said separable contacts and insulating means with respect to said biasing means to increase the operating force of said biasing means, and means responsive to a predetermined movement 01 said separable contacts for releasing said separable contacts and insulating means for movement of said contacts to the open circuit position and of said insulating means to a position therebetween.

35. In a circuit interrupter, a support, a casing mounted thereon and having limited relative movement therewith, separabl contacts in said casing, resilient means in said casing andconnecting said casing and at least one of said contacts-whereby relative movement 01' said casing in one direction will stress said resilient means in a direction to move saidcontacts to the open circuit position, latch means in said casing for normally holdingsaid separable contacts in the closed position, and means responsiv to a predetermined relative movement of said casing for tripping said latch means to cause said biasing means to quickly open said contacts. I

36. In a circuit interrupter, a support, a cas-.

ing mounted thereon and having limited rela- 3'7. In a circuit interrupter, a. support, a casing mounted thereon and having limited relative movement therewith, separable'contacts within said casing arranged for movement therewith at least during a portion of the movement or said casing, latch means tor holding said contacts in the closed circuit position, operating mean for moving said casing with respect to said support, at least one of said contacts having relative movement with respect to said casing and another of said contacts following release of said latch means, means responsive to predetermined movement of said casing for releasing said latch means, and biasing means operative to move said one contact with respect to another of said contacts following release of said latch means.

38. In a circuit interrupter, a pair of separable disconnecting contacts, arc extinguishing means having separable arc establishing contact means. biasing means for actuating said arc establishing contacts means to open circuit position, latch means for restraining the action oi said biasing means, and a movable operating member operative upon continuous movement in one direction for initially releasing said latch means to cause the circuit to be opened at said arc establishing contact means and'for subsequently causing said pair of disconnecting contacts to separate to insert an isolating break in the circuit.

39. In a circuit interrupter, a pair of separable disconnecting contacts, arc extinguishing means having separable arc establishing contact means, biasing means for actuating. said arc establishing contact means to open circuit position, latch I means for restraining the action oi. said biasingmeans, a movable operating member operative upon continuous movement thereof in one direction for initially releasing said latch means to cause the circuit to be opened at said are establishing contact means and for subsequently causing said pair of disconnecting contacts to separate to insert an isolating break in the circuit, said operating member upon movement in the opposite direction causing said biasing means said terminals, said bridging means including separable contact means, spring means biasing said contact means to the open circuit position; latch means holding said contact means in the closed position against the bias of said spring means, and operating means operable-in one continuous movement for first releasing said latch means to cause said spring means to move said contact means to the open circuit position and for thereafter moving said bridging means out of engagement with at least one of said terminals.

41. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least one 0! said terminals, said bridging means including separable contact means, spring means biasing said contact means to the open circuit position, latch means holding said contact means'in the closed position against the bias of said spring means, and operating means operable in one continuous movement for first releasing said latch means to cause said spring means to move said contact means to the open circuit position and for'thereatter moving said bridging means out of engagement with at least one of said terminals, and means operable in response to movement'of said bridging means for moving said separable contact means to the closed circuit position. v 1 l 42. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least one 01' said terminals, said one terminal having limited relative movement with respect to said bridging means. without breaking contact during the initial opening movement 01 said bridging means, said bridging means including separable con tact means, spring means operating said contact means to open circuit position, latch means for restraining the action of said spring means, operating means for moving said bridging means out of engagement with at least said one terminal, and means actuated by said operating means during the limited relative movement between said one terminal and said bridging means for releasing said latch means to cause said spring means to move said contact means to the open circuit position.

43. In a circuit interrupter, a pair of concentric tubes of insulating material defining an annular arc passage, separable contact means for drawing an are adjacent one end of said are passage, and a third tube of insulating material relatively movable between said pair of concentric tubes for causing said are to be restricted in cross-section and lengthened along a path substantially twice the length of the relative movement between said last-named tube and said pair of concentric tubes, and operating means extending through at least one oi-said pair of concentric tubes.

for actuating said are establishing contact means to be relatched in the closed circuit position and movement of said pair of disconnecting contacts to the closed circuit position.

40. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrically connecting said terminals and movable into and out of engagement with at least one or 44. In a circuit interrupting device, a pair of spaced terminals, bridging mean normally electrically connecting said terminals and movable into and out 01' engagement with at least one of said terminals, said-one terminal having limited movement with said bridging means during the initial movement of said bridging means towards the open circuit position, said bridging means including separable, contact means, operating means for operating said bridging means out of engagement with at least said one terminal, and

means actuated by said operating means during the limited movement of said one terminal with said bridging means for moving said contact means to their open circuit position.

45. In a circuit interrupting device, a pair of spaced terminals, bridging means normally electrlcally connecting said terminals and movable into and out of engagement with at least one 01' said terminals, said one terminal having limited movement with said bridging means during the initial movement or said bridging means towards the open circuit position, said bridging means including separable contact means, operating means for operating said bridging means out of engagement with at least said one terminal, means actuated by said operating means during the limited movement of said one terminal with said bridging means for moving said contact means to their open circuit position, and means operable in response to movement of said bridging means following disengagement oi the latter from said one terminal tor reclosing said contact means.

46. Circuit interrupting means including three spaced terminals, insulating means supporting said terminals, a pair of circuit interrupting devices supported on said terminals, each of said devices connecting a pair 01 said terminals with one terminal common to both devices, one said devices being movably mounted on one of its associated terminals for movement into and out of engagement with the other of its terminals, and the other of said devices being connected to said common terminal between its insulating support and the other of said devices.

47. Circuit interrupting means including three insulated spaced terminals, a pair of circuit interrupting devices supported on said terminals, each of said devices connecting a pair of said terminals with one terminal common to both devices, one of said devices comprising an expulsion type interrupting device and having the end thereof which is open upon the occurrence of an interrupting operation mounted on said common terminal outwardly of the other or said devices so as to be directed angularly away from. said other device, to direct the products or ex pulsion angularly away from said other device.

48. In a circuit interrupter, a pair or concentric tubes of insulating material defining an annular arc passage, separable contact means for drawing an are adjacent one end of said are passage, and a third tube of insulating material relatively movable between said pair of concen tric tubes for causing said arc to be restricted in cross-section and lengthened along a path substantially twice the length of the relative movement between said last-named tube and said pair of concentric tubes, and means extending through the inner one of said concentric tubes and connected to said contact means.

49. In a circuit interrupter, a blade member mounted for movement into and out of engagem'ent with respect to a cooperating contact member, said contact member being mounted for limited movement with said blade member but angularly thereto adjacent the closed position of said members, one oi said members adapted to receive the other, and at least one of said members having a tapered engaging portion adapted to be moved into and out 01' high pressure engagement with the other of said members during said movement or said members together,

50. In a circuit interrupter, a blade member mounted for movement into and out of engagement with respect to a cooperating contact memlimited movement with said blade member but angularly thereto adjacent the closed position of said members, said blade member having a wedge-shaped contact portion for engaging a' yoke portion on said contact member so that said portions are movable into and out of high pressure engagement with the other of said members during said movement of said members together.

51. In a circuit interrupter, arc-extinguishing means including separable contacts normally held in a closed circuit position, means of insulating material movable to a position between said contacts, biasing means for actuating said contacts to the open circuit position and said insulating means to said position between said contacts, operating means for stressing said biasing means, and means responsive to a predetermined movement of said operating means for releasing said separable contacts and insulating means for movement of said contacts to the open circuit position and or said insulating means to a position therebetween.

52. The combination with a switch having a terminal member and blade means operable into and out of engagement with said terminal member of an arc extinguishing device having 9. casing, a circuit through said casing including separable contacts at least one of which is connected to said terminal member, means for releasably connecting said blade means with another 01' said separable contacts to establish a circuit in parallel with the gap formed between said ter-' minal member and said blade means, means Ior biasing said separable contacts to the open circuit position, and means responsive to movement of said blade means for controlling said biasing means to separate said separable contacts to quickly open the circuit after said blade means has moved out of engagement with said terminal member, and prior to release or said blade means from the contact with which it is associated.

53. The combination with a switch having a terminal member and blade means operable into and out of engagement with said terminal member of an arc extinguishing device having a casing, a circuit through said casing including separable contacts at least one of which is connected to said terminal member, means for releasably connecting said blade means with another oi said separable contacts to establish a circuit in paraliel with the gap formed between said terminal member and said blade means, means for biasing said separable contacts to the open circuit position, and means responsive to movement of said blade. means for controlling said biasing means to separate said separable contacts to quickly open the circuit after said blade means has moved out of engagement with said terminal member, and prior to release of said blade means from the contact with which it is associated, and said blade means upon movement thereof in a reverse direction toward said terminal member adapted to first releasably engage said other contact 01' said arc extinguishing device, and said controlling means being responsive to said reverse movement of said blade means to thereafter cause engagement oi said contacts.

54, In a circuit interrupter, a pair of spaced terminals, a bridging member plvotally mounted on one of said terminals for swinging movement into and out of engagement with the other 01 said terminals, an engageable latching lever pivotally mounted adjacent the free end of said bridging member for normally holding said bridging member in the closed circuit position, said lever being pivotally movable to latch and unlatch said bridging member in the closed circuit position, stop means limiting pivotal movement of said lever whereby a continuous pull exerted on said lever in one direction will first release said bridging member and thereafter cause pivotal movement thereof to an open circuit position, separable contacts within said bridging member biased to the open circuit position, means for latching said separable contacts in the closed circuit position, and'means actuated by pivotal movement of said latching lever to release said separable contact latching means to cause said contacts to interrupt the circuit prior to movement of said bridging means out of engagement with said other terminal.

55. The combination with a switch having a terminal member and blade means operable into and out of engagement with said terminal member of an arc extinguishing device having a casing mounted on said terminal member. a circuit through said casing including separable contacts at least one of which is connected to said terminal member, means for releasably connecting said blade means with another of said separable contacts to establish a circuit in parallel with the gap formed between said terminal member and said blade means, means for biasing said separable contacts to the open circuit position, and means responsive to movement of said blade means for controlling said biasing means to separate said separable contacts to quickly open the circuit after said blade means has moved out of engagement with said terminal member, and prior to release 01 said blade means from the contact with which it is associated.

56. The combination with a switch having a terminal member and blade means operable .into and out of engagement with said terminal member of an arc extinguishing device having a casing, a circuit through said casing including separable contacts at least one of which is connected to said terminal member, means for releasably connecting said blade means with another of said separable contacts to establish a circuit in parallel with the gap formed between said terminal member and said blade means, means for biasing said separable contacts to the open circuit position, means responsive to movement of said blade means for controlling said biasing means to separate said separable contacts to quickly open the circuit after said blade means has moved out of engagement with said terminal member prior to release oi said blade means from the contact with which it is associated, and means operable continuously in one direction for moving said blade means to an open circuit position at which it is spaced from said terminal member and said other of said separable contacts, whereby in a circuit interrupting operation said blade mean is first separated from said terminal member but remains in engagement with said other or said separable contacts, thereafter said contacts are quickly separated to interrupt the circuit, and then said connection of said blade means and contact is released, and finally said blade means moves to the aforesaid open circuit position.

57. The combination with a switch having a terminal member and blade means operable into and out of engagement with said terminal member of an arc extinguishing device having a casing, a circuit through said casing including separable contacts at least one 01 which is connected to said terminal member, means for releasably connecting said blade means with another 0! said separable contacts to establish a circuit in parallel with the gap formed between said terminal member and said blade means, means for biasing said separable contacts to the open circuit position, means responsive to movement of said blade means for controlling said biasing means to separate said separable contactsto quickly open the circuit after said blade means has moved out of engagement with said terminal member prior to release of said blade means from the contact with which it is associated, means operable continuously in one direction for moving said blade means to an open circuit position at which it is spaced from said terminal member and said other oi! said separable contacts, whereby in a circuit interrupting operation said blade means is first separated from said terminal member but remains in engagement with said other of said separable contacts, thereafter said contacts are quickly separated to interrupt the circuit, and then said connection of said blade means and contact is released, and finally said blade means moves to the aforesaid open circuit position, and said operating means upon reverse movement thereof adapted to move said blade means into engagement with said terminal member, whereby in a circuit closing operation said blade means is first moved into engagement with said other of said separable contacts, and thereafter said controlling means being responsive to iurher movement of said blade means toward said terminal member to close said separable contacts.

LEON R. LUDWIG. JAMES H. FRAKES. MARTHA M. SCHOFIELD, Administratrix of the Estate of Stanley T. Schofleld, Deceased.

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