US2267399A - Electric circuit interrupter - Google Patents

Description

Dec. 23,` 1941. s. FARRER :a1-AL 2,267,399

ELECTRIC CIRCUIT INTERRUPTER v Filed May 17, 1940' Pagg.

Inventor-s Sydney Farr-er; George Pailn,

heur' Attorney.

Patented Dec. 2.3, 1941 ELECTRIC CIRCUIT INTERIHJPTERl Sydney Farrer, Lynwood Grove, Sale, and George Pailin, Higher Openshaw, Manchester, England, assignors to General Electric Company, a corporation of New York Application May 17, 1940, Serial No. 335,858 In Great Britain June 1, 1939 6 Claims.

Our invention relates to electric circuit interrupters of the fluid-blast type in which interruption of the circuit is effected by a blast of arc-- extinguishing fluid through the arc drawn during circuit interruption and more particularly is an improvement on United States Letters Patent 2,146,656 granted February 7, 1939, upon an vapplication of'W. F. Skeats and assigned to the same assignee as the present invention.

It is an object of our invention to provide a new and improved air circuit breaker of the gas-blast type havinga large interrupting capacity which is simple and compact and which is effective to interrupt currents of greatly varying magnitudes. Another object of our invention is the provision of a simple and compact circuit-breaker construction embodying means for drawing a plurality of arcs in series, one of which causes the generation of the gas under pressure during circuit interruption, which is driven across the other arc to extinguish the same and interrupt the circuit.

. While not limited thereto, our invention is particularly applicable to gas-blast breakers of the type wherein an arc-extinguishing gas is emitted which is mounted a fixed electrode I2 projecting axially into the chamber defined by cylinder I0.

Fixed electrode I2 is illustrated as being capable of limited movement against the bias of a spring I3 so as to provide the necessary wipe when cooperating with a movable electrode, to be described hereinafter, during the circuit-closing and opening operation. The cap II is also provided with a suitable terminal, not shown, for connecting the cap to the external electrical circuit I4. l

A rod Contact I5 is mounted axially within cylinder I and arranged for reciprocation 'withm in the latter by any suitable operating mechanism, not shown, which may be disposed outside said cylinder to open and close the circuit as desired. One end of said rod contact I is provided with a suitable electrode or butt Contact from the walls of an arc-confining chamber under the influence of the arc and it is, accordingly, an object of this invention to provide a new and improved circuit breaker of this type.

Further objects and advantages of our invention .will become apparent as the following deseription proceeds and the features; of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this speciiication.

For a better understanding of our invention, reference may be had to the accompanying drawing in which Fig. 1 is a cross-sectional View of a circuit breaker embodying our invention, Fig. 2 illustrates another modication of our invention,

Fig. 3 is a modification of the arrangement shown in Fig. l, Fig. 4 represents still another modification of our invention, Fig. 5 is a cross-sectional view taken on line 5-5 of Fig. 4, Fig. 6 is a view similar to Fig. representing a modification of the arrangement of Fig. 4, Fig. 'I is a cross-sectional view of another modification of our invention, while Fig. 8 is another view of the arrangement of Fig. '7.

Referring now'to Fig. 1, we have provided' in an electric circuit interrupter of the gas-blast type an arc-extinguishing structure comprising a chamber defined by a cylinder or casing of insulating material 10, which is closed at one end by I6 cooperating with fixed electrode or contact I2.

' Although we have illustrated electrodes l2 and I6 as of the butt-contact type, it will be understood by those skilled in the art that any suitable type of contacts may be used.

Insulating cylinder ID houses in fixed relationship therewith a second stationary contact member Il which is disposed towards the end of cylinder lremote from the enclosing cap Ii. Fixed contact I1 may be of any suitable type and is illustrated as comprising a plurality of members held together by means of a garter spring I8 so as to form a sleeve-type contact.- A suitable connection I9 leads from stationary Contact I1 to the exterior of the cylinder I0 so that connection withv the external electric circuit, not shown, may be made. Rod contact I5 is provided with a movable contact in the form of a collar 2|] which may be formed integrally therewith, as shown, and is adapted to engage with stationary contact II in the closed position of the circuit breaker. In order to provide for series breaks in the electric circuit through the circuit breaker, the moV- v able rod contact I5 is provided-with a sleeve 2l of insulating material, such as horn fiber, which evolves an arc-extinguishing gas when subjectedl means of a metal cap II threaded thereto von are provided cylindrical masses of insulating material 22, 23, 2t, and 25 disposed within insulating cylinder lll so that shrouded rod contact i5 moves through a closely tting axial bore 2l provided in this mass of insulating material. Insulating material 23, 24, and 25 are preferably composed of a gas-evolving substance, such as horn fiber or the like, so as to produce an arcextinguishing gas when subjected to the heat or contact of an arc. A suitable passage 28, substantially parallel to the axis of cylinder it, is ,provided in the mass of insulating material 22 so as to interconect the pressure-generating space adjacent collar 20 with the space adjacent electrodes l2 and i6, all within insulating cylinder lll. Arc-extinguishing gas produced in the chamber adjacent collar 20 is forced through passage 28 where it is cooled by the walls of the passage and thereafter enters the space within cylinder I adjacent xed contact l2.

The wall of cylinder it adjacent contact i2 is between the pairs of separable contacts, there so that the arc-extinguishing gas from passage 28 may be deflected by end cap li and driven lacross the'arc drawn between electrodes i2 and I 6. To aid in extinguishing this arc, we have provided a plurality oi bailies 3@ closely adjacent the path of movement of rod contact i5 and perpendicularly arranged with respect to such path, these baliles being disposed at progressively greater .axial distances from xed contact l2. Preferably, these baiiles have the portions thereof adjacent the path of movement of rod contact` l5 formed of a conducting material or metal 39a and are provided with continuations of insulating material 36h so as to tend to segregate the arc into a plurality of portions when driven into this baie structure. The conducting portions 39a of b aiiles 3U are preferably connected with different tapping points of a resistance tl, one yend of vwhich is connected with the end cap ii and the purpose of Which will be set forth in greater detail hereinafter.

.As a further aid indnterrupting the circuit, the wallof cylinder i@ and the masses of insulating material 22, 23 are constructed to provide a radial passage 32 to the exterior of cylinder or casing l past which electrode it isA eventually ,moved and through which a cross blast of gas mayilow for causing the iinal interruption of the circuit.

'In the operationvof the above-described arrangement upon axial movement of rod contact i5 to cause separation of the electrodes, collar 2@ willilrst be disengaged from stationary contact ll whereby an arc will be drawn and pressure set up in the space enclosing said collar and associated contact. Furthermore, the action of the heat of the arc on gas-evolving material 2d will cause the generation ofA large amounts of arcfini ratedto drawa second arc and this gas will be 'deflected so as to now across this .second are forcing it into the bailley structure comprising bailles 30. `.ils electrode iii moves past the conducting portion 30a of therst baille at, the arc will be urged against said conducting -bar by the cross gasblast so that a portion of resistance 3l .will be placed in .parallel with the varc and eventually the arc current will be transferred to such portion of the resistance and the `arc between electrode l2 and conducting portion 30a of the iirst baille 30 will be extinguished. Similarly, as the end of electrode'l moves past the 00naaeaeee l xlv. when electrode i6 moves past the conducting portion of the last baille 30, which position isI -shown in Fig. l, the arc will be connected ln serleswith all of resistance 3i. It will be seen that, `-`with this arrangement, resistance is inserted in series with the arc and the value of this resistance progressively increased whereby the current which is finally interrupted is very much reduced. When electrode le moves past radial passage S2, the blast of gas through this passage across the are will cause iinal interruption of the circuit.

By arranging the masses of insulating material 22 and 23 so as to closely conne shrouded rod contact l. substantially all of the gas produced adjacent collar 2@ is caused to ow across the arc and is available for extinction of the latter.A

Gas-evolving insulating materialz is also preferably arranged to closely confine collar 2u so as to increase the arc-extinguishing gas produced.

In Fig. 2, we have shown a'modiication of the circuit breaker of Fig. 1 in which material of the arc-quenching gas-producing type and a shrouded rod contactare employed but which is not arranged for inserting resistance in the circuit to be interrupted. This circuit breaker also comprises an insulating casing or cylinder till, which denes a chamber 33. One end of this chamber is closed by means of an end cap 35 provided with a central opening 3d and which houses a resilient socket contact 8l extending axially into chamber 33. This socket contact or electrode 3l cooperates with an electrode 3d mcuntedon the end of rod contact 39 which is arranged for reciprocation within cylinder 3Q iby a suitable operating mechanism, not shown. As in Fig. 1, rod contact 89 is provided, with an'insulating sleeve or shroud it preferably of gas-producing material and a collar il which cooperates with a suitable stationary contact l2 mounted in cylinder Si remote from metal end cap 35 and in axial alignment with iixed contact 3l. Fixed contacts @l and d2 are suitably connected to an external circuit et. The arrangement of contacts 8l, 38, di, i2 is preferably such that collar di will be vdisengaged from the stationary contact d2 tov draw an arc before the electrode 38 mounted on the end of rod contact 3S uncovers the opening or discharge port 36 in cap 35 whereby pressure will be set up within chamber t3 by the action of. the arc, which pressure is suddenly relieved upon separation of contacts 3l and 38 and a sudden discharge of the gas produced in the chamber 33 is obtained adjacent the second arc drawn.

Cylinder 36 is preferably provided with a' plurality of axially spaced annular disks M of opening through which rod contact 3s is adapted to move and are provided with perfcrations gas flowing in this manner will be obtained as rod through which'the gas produced by the arc drawn between collarlli and fixed contact t2 is adaptedcto iow axially of the cylinder 3d. In

this arrangement, the gas produced will flow radially on to the arc all around the latter and a progressively greater number oi streams of the contact 39 recedes from the end cap 35 past the several disks 44 in succession.

Instead of being of circular form as illustrated, it will be understood by those skilled in the art that rod contact 39 may be of rectangular section disposed so that the gas iiows in the direction of the wider dimension of said rod, that is to say, so that the width of the gas path corresponds to the narrower vdimension of the rod contact, whereby the discharge outlet 36 may, because it is narrow, be comparatively small and the available arc-quenching gases more efficiently utilized for the extinction of the arc.

'Ihe operation of the circuit breaker of Fig. 2 will be understood from the description set forth in connection with Fig. 1.

In Fig. 3, we have disclosed a modification of the circuit breaker of Fig. 1 wherein the operation of the contacts is inverted. Accordingly, as in Fig. 1, we have illustrated an insulating casing 41 having one end thereof closed by a cap 48 suitably supporting a fixed contact 49 extending axially into the chamber defined by casing 41. As in Fig. 1, a shrouded rod contact 50 provided with an insulating sleeve of gas-evolving material i is arranged for axial movement within casing 41 and one end thereof is provided with an lelectrode 52 'for cooperating with fixed contact 49. Rod contact 50 is also provided with a collar 53 which is arranged to cooperate with a suitable stationary contact 54. Contacts 49 and 54 are suitably connected -to 'the external electric circuit, `not shown. Electrode 52 and collar 53 are so arranged on rodcontact 50 as contrasted with the corresponding parts of Fig. 1 that an arc is drawn first between electrodes or contacts 49 and 52 so as to produce a gas pressure which is used to extinguish the arc later drawn between collar 53 and stationary contact 54. Preferably, rod contact 50 is provided with a central axial bore 55 terlal which is mounted to reciprocate with rod contact 50. Said cylindrical block 5I is provided i with one or more longitudinal vpassages 32 by which the arc gases are led along the rod to an opening 5B in the side of collar 53 where they are deflected to form a cross blast as is described hereinafter. Insulating cylinder or casing 41 is providedwith an opening 51 in the form oi an arc chute adjacent stationary contact 54 on the side thereof remote Afrom end cap 43. Suitable baliies 58 similar to baiiles 39 of Fig. 1 are disposed across discharge opening or arc chute 51 in the wall of cylinder 41. As in Fig. 1, these bafiles are preferably provided with conducting portions 58a adjacent collar 53 and insulating portions 58h remote from collar 53. To aid in interrupting the arc, a resistance, not shown, similar to resistance 3l of Fig. l is preferably connected -to fixed contact 54 and tapping points thereof are connected to the conducting portions 58a of baiiles 53. V

By means of the axial bore or passage in rod contact 50, an increased tendency to arc extinction is obtained since the gases formed between electrodes 49 and 52 will be cooled and any metallic vapor produced by the arc will be condensed in flowing-through this passage. Preferably electrodes 49 and 52 are closely shrouded by sleeves of gas-producing material 59 and 60. It will be seen, furthermore, that with this arrangement, the gases produced adjacent the electrodes 49 and 52 are compelled to flow through passage 55 thereby driving the arc drawn between collar 53 and fixed contact 54 into the arc chute 51 and baffle structure comprising bafiles 58.

It may also be desirable to provide a flow of gas external of rod contact 50 and, accordingly, we have provided a cylinder 6l of insulating mathrough which the gases produced adjacent contact 49 pass to the discharge outlet or arc chute 51v in casing 41. These passages i2 also serve to cool the gases produced and to condense any metallic vapor incident to the drawing of the arc between elec-trodes 49 and` 52. As in Fig. 1, .insulating material 5|, 59, 69, and 6| is preferably formed of fiber or other gas-evolving material so as to produce large quantities of arc-quenching gas.

The operation of the cross-blast air circuit breaker of Fig. 3 will be obvious to those skilled in the art in view of the detailed description set forth in connection with Fig. l.

In Figs. 1 to 3, we have disclosed air-blast circuit breakers of the type wherein two arcs in series are drawn, one to generate a gas pressure which will extinguish the other arc drawn. It will be understood by those skilled in the art that it is not essential in carrying out this invention that the arc over which the gases produced are caused to flow should be separate from the arc producing these gases. Thus, the arrangement may b'e such that separation of a pair of contacts results initially in drawing an arc by which gas pressure is obtained while further movement of the contacts opens passages by which the pressure is released and a flow of gas obtained across the arc for extinguishing purposes. Such an arrangement is shown in Figs. 4 and 5 wherein a fixed socket contact 64 is mounted within a chamber or enclosure 53 defined by suitable cupshaped structure having a threaded extension 66 adapted to be connected to an external electrical circuit, not shown. Cup-shaped member 65 is closed by means of a block of insulating material $1 constructed with a passage extending perpendicularly to the axis of member 55 and ending in an arc chute 68. This arc chute communicates with chamber 63 by means of a passageA 69. Asuitable rod contact 1l is arranged for reciprocal movement Within the enclosure 53 and is adapted to cooperate with stationary or fixed contact 64. The end of rod contact 10 cooperating with contact 64 is made hollow in order to accommodate a suitable filler pencil 12 preferably made of a hard fiber or suitable articial resin for producing arc-extinguishing gas when subjected to the action of the arc. Rod contact 10 moves through an opening 1| in the wall of insulating block 61 remote from fixed con tact 64.

Secured to insulating block 61 within the 'enclosure 63 is a cylindrical body 13 of gas-produc-v ing material of any suitable type such as fiber or the like which is provided with a central perforation through which rod contact 10 is adapted to move while being engaged or disengaged from stationary contact 64. Cylindrical body 13 and socket contact 64 practically fill the enclosure $3 defined by cup-shaped structure 65 and insu1at.

ing block 61. A plurality of radialpassages 14 are provided in cylindrical. body 13 extending from the center to the periphery thereof,v the purpose of which will be hereinafter described.

Rod contact 10 moves with only a very small clearance through the bore ci the gas-producing material 13 and the passage 69 leading to arc chute 68 so that the inner surfaces of said passages areclosely adjacent the sides of the Contact rod, as best shown in Fig. 5. It will be seenthat, with this arrangement upon retraccontact 64, an arc will be drawn which will act upon the gas-producing material making up the,

iiller pencil l2 and the cylindrical body 13, thereby producing considerable quantities of arc-quenching gas. This gas will vbe retained within the enclosure 63 until the end of the rod contactlll moves into the passage 89 leading to arc chute 68 when the flow of gas in passage 69 is deflected so as to be directed across the arc into arc chute 68 to extinguish the same. Suitable baiiies 'l5 which comprise a metal portion 15a adjacent contact rod 18 and an insulating portion ll5b remote from rod contact 'l are provided. As in Fig. 1, the conducting portions a v quired contact pressure is obtained by virtue of u of bailles 'l5 may be associated with different tapvping points of a resistance, not shown, the end of which would be electrically connected to stationary contact 64. It will be seen from Figs. 4 and 5 that we have provided an arrangement wherein the arc-extinguishing gas or uid generated around contact 84 is prevented from passing across said arc until there has been a predetermined separation of the contacts whereby interruption of the arc may take place without danger of restriking.

Although in Figs. 4 and 5, rod contact 18 has been indicated as of circular cross section, it could just aswell be of rectangular cross section. In Fig'. 6, we]` have shown a rod contact '6 of rectangular cross section associated with a cir` cuit breaker otherwise identical with that shown 85, suitably raised.y contact surfacesl may be provided on each of the fingers 85 adjacent deprising a at strip of conducting material which is arranged to move through the aperture 88 in the enclosure 1l. In the closed circuit position,

rod contact 88 is adapted to be moved between the two sets of contact lingers 85 and the recompression springs 86.

A pair of movable ilat plates 88, ,which are formed of a suitable gas-producing material, is mounted within the enclosure Tl and extend entirely across the space therein. These plates able stors 943 are provided to limit the movement' of these plates toward one another. The upper` end of vrod contact 88 is rounded and the cooperating edges of gas-producing plates 89 are chamfered so that, when the'moving contact is moved upwardly, the gas-producing plates 88 will be forced apart so thatz rod contact 88 may engage with the iixed contact comprising fingers The free space between side plates 'i8 may be filled with additional plates 98 of gas-producing material.- As in Fig. 4, a 'plurality of baiiies 95 are provided in arc chute 8l which preferably have the portions thereof adjacent rod contact 88 formed of a metal connected to suitv able tapping points on a resistance 96 having one the evolution of a gas from insulating members.

is depended upon to produce an arc-quenching gas, it has often been found that arcs of low- Acurrent value are incapable of levolving a sulli` cient amount of gas whereas, if thespace within which the gas is produced is decreased, arcs of high-current values develop such destructive pressures that the confining structure will be damaged. Accordingly, in Figs. 7 and 8, we have disclosed a cross-blast circuit breaker having a single break similar to the'one shown in Fig. 4 which overcomes the diiliculty just mentioned.

' A suitable arc-coniining chamber 'll is provided which is dened by means of a pair of side plates f 18 which are disposed parallel with and closely adjacent to one another, being secured together by blocks or plates of insulating material 18. Fig. 8 is a side view of the circuit breaker of Fig. '1 with one of the plates 'l8 removed. Chamber` 'Il is provided with a rectangular aperture 80 at one end and an opening and arc chute 8| disposed substantially midway along one side of the structure.v rl'fheend of chamber 'll-remote from aperture 80 is closed by means oi a ixed contact assembly 82 comprising an extension 83 adapted to be connected to an external electrical circuit, not shown and a central depending tongue 84 extending into chamber 1l. -A plurality of contact ilngers 85 are suitably mounted on each side of this depending tongue 84 and "biased toward one another by spring means 88.

In order toassure good electrical contact between-depending tongue 84 and contactin'gers` end thereof connected to the fixed` contact assembly 82.

plates so that it will have an increased eiect in 4evolving the arc-quenching gas from plates 89. Since the plates 89 extend into the arc chute 8l, the gas stream resulting from the abovedescribed operation is discharged as a blast forcing the Aarc into the baffle structure in a mannerl described in connection with Fig. 1. As will be understood by those skilled in the art, should any excess gas pressure arise within the structure due to breaking circuit on heavy current, such excess pressure will result in the gas-producing plates 89 being forced away from one another against the biasing springs 93 to relieve the pressure. v

As will be understood by those s killed in the arc-quenching gas may be of any suitable kind, for example, resins, vulcanite, ber, ebonite, halogenated diphenyl ketones or dibenzyls, methyl methacrylat'e, and other available materials.

While we have described certain particular embodiments of :our invention, it will be obvious to those skilled in the art that various changes and `modifications may be made without departing from our invention and w e, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention:

What we claim as new and desire to secure by Letters Patent of the United States is:

l. In a circuit-interrupting device comprising an arc chamber including a plurality ofspaced annular fixed electrodes mounted therein in axial alignment, an elongated rod contact of 'conducting material having spaced contact portions separated by a sleeve of insulating material arranged for axial movement in said chamber, said contact portions being spaced to engage said iixed electrodes in the closed circuit position and separable therefrom so as to draw arcs between said contacts and electrodes, means formed of gasevolving insulating material for generating a gas and developing a pressure in said chamber under the iniiuence of one of said arcs defining a passageway in said chamber for leading said gas in a direction substantially parallel with the axis of said chamber, and deecting means for causing a blast of said gas to flow across said other arc to extinguish the same.

2. In a circuit-interrupting device comprising Y a casing having an arc chute associated therewith, a pressure chamber in said casing communicating with said arc chute, means including an elongated rod Contact having a pair of contact portions thereon separated by a sleeve of insulating material for drawing a plurality of arcs in said casing, one adjacent said arc chute and another in said pressure chamber, means formed of gas-evolving insulating material for generating a gas and developing a pressure under the influence of one of said arcs deiining a passageway in said chamber for leading said gas in the direction of said arc chute across the arc adjacent thereto, a barile structure in said arc chute comprising a plurality of spaced plates disposed close to and edgewise with respect to the arc adjacent said are chute, the portion of said plates near said arc being formed of a conducting material, and a resistance including a plurality of tapping points, each connected to one of said conducting portions of said plates and so constructed and arranged that portions thereof are'progressively connected in series with said arcs during the circuit-interrupting operation of said device.

3. In a circuit-interrupting device comprising an arc chamber having an arc chute associated therewith and including a plurality of iixed electrodes mounted therein in axial alignment, an elongated rod contact of conducting material having spaced contact portions separated by a sleeve of insulating material arranged for axial movement in said chamber, said contact portions being spaced to engage said xed electrodes in the closed circuit position and separable therefrom sc as to draw arcs between said contacts and electrodes, means formed of a gas-evolving insulating material for generating a gas and developing a pressure in said chamber under the influence of one of said arcs defining a passageway in said chamber for leading said gas in a direction substantially parallel with the axis of said chamber toward said arc chute, and defiecting means for causing a blast of said gas to iiow across said other arc into said arc chute to extinguish the same.

4. An electric circuit breakercomprising an arc-confining chamber, a plurality of spaced fixed contacts mounted in axial alignment in said chamber, an elongated movable rod contact of. conducting material having spaced contact portions separated by a sleeve of gas-emitting insulating material, said contact portions being spaced to engage said fixed contacts in the closed circuit position of said breaker and separable therefrom by movement of said rod contact in an axial direction with respect to said fixed contacts, means for generating an arc-extinguishing iiuid adjacent one of said xed contacts under the influence of the arc associated with Vrable therefrom so as to said last-mentioned contact, means formed of gas-evolving insulating material defining a passageway in said chamber for leading said gas in a direction substantially parallel with the axis of said chamber toward another of said fixed contacts. and deflecting means for causing a blast of said gas to flow across the arc associated with said last-mentioned xed contact to extinguish the same.

5. In a circuit-interrupting device comprising an arc chamber including a plurality of.spac ed annular xed electrodes mounted therein in axial alignment, an elongated rod contact oi conducting material having spaced contact portions separated by a sleeve of insulating material arranged for axial movement'in said chamber, said contact portions being spaced to engage said xed electrodes in the closed circuit position and'sepadraw arcs between said contacts and electrodes, means for generating a gas and developing a pressure in saidv chamber under the iniiuence of one of said arcs, means formed of a gas-evolving material for dening a passageway in said chamber for leading said gas in a direction substantially parallel with the axis of said chamber, and means for causing said gas to iiow radially on to said other arc in a progressively greater number of streams as said rod contact moves with respect to said xed electrodes.v

6. An electric circuit breaker comprising an arc-conning chamber, a plurality of spaced iixed contacts mounted in axial alignment in said chamber, an elongated movable rod contact of conducting material having spaced contact portions separatedby a sleeve of gas-emitting insulating material, said contact portions being spaced to engage said xed contacts in the closedcircuit position of said breaker and separable .therefrom by movement of said rod contact in an axial direction with respect to said xed contacts, means for generating an arc-extinguishing fluid adjacent one of said xed contacts under the influence of the arc associated with said lastmentioned contact, a passageway in said chamber for leading said gas in a direction substantially parallel with the axis of said chamber toward a second fixed contact, and .means for causing said gas to ilow radially on to said arc associated with said second xed-contact in a progressively greater number of streams as said arc associated with said second fixed contact is increased in length.

.SYDNEY FARRER. GEORGE PAmrN.

6 "RTI'FICATE oFv ooREcTor.

Patent No. 2,267,599. December 25, 19in. A

- SYDNEY FARRER, ET AL.

It is hereby certified that error appears in the-printed specification :of the above numbered patent requiring correction as follows: Page 2, first column, line 2l, strike out "between the pairs of separable contacts, there'r and insert ."instead --provided witha suitable discharge opening 29"; page 5, second column, line 57, cla-11115', before "material" insert --insu1ating; and that the said Letters Patent should be read with this correction .there- 1x1-'that the samemay conform to the record of the case in the Patent Office.'

signed mi sealed this 5rd de; of naz-ch, A. D. 191m.

Henry Van Arsdale, (Seal) Acting Commissioner of Patente.

6 .RT'I'ICATE 0F ooR'E'ori.

Pax-.mt No. 2,267,599. December 25, 19m. l,

- SYDNEY FAHBER, ET AL.

It is hereby certified that error appears in the-printed specification :of the above numbered patent requiring correction as follows: Page 2, first column, line 21, strike out between the pairs of separable contacts there'r and insert "instead --provided witha suitable discharge opening 29"; page 5, seoo'nd colmnn, line 57, claims', before "material" insert insu1ating; and that the said Letters 4Patent should be read with this correction therein'umt the as me'may confer-m to the record of the case 1n the Patent office.-

sigmd'dm sealed this 5rd any of naz-ch, A. D. 19b,2.

4 Henry Van Arsdale, (Seal) A Acting Commissioner of Patents.

Images