US2668205A

US2668205A - Multipole circuit breaker

Info

Publication number: US2668205A
Application number: US254065A
Authority: US
Inventors: Felix E Myers
Original assignee: ITE Circuit Breaker Co
Current assignee: ITE Circuit Breaker Co
Priority date: 1951-10-31
Filing date: 1951-10-31
Publication date: 1954-02-02
Anticipated expiration: 1971-02-02

Description

Feb. 2, 1954 Filed OCC. 3l, 1951 F. E. MYERS MULTIPOLE CIRCUIT BREAKER 4 Sheets-Sheet l www Feb. 2, 1954 F. E. MYERS 2,668,205

MULTIPOLE CIRCUIT BREAKER Filed Oct. 31, 1951 4 Sheets-Sheet 2 LEE . INVENTOR. FEL/x E. Mygs' Feb. 2, 1954 F. E. MYERS MULTIPOLE CIRCUIT BREAKER Filed Oct. 5l, 1951 4 Sheets-Sheet 5 ATTO/e/VEKS Feb. 2, 1954 F, E, MYERS 2,668,205

MULTIPOLE CIRCUIT BREAKER Filed Oct. 3l, 1951 4 Sheets-Sheet 4 Ill 11111111111111111111/lll/IIIA 'lll/l//ll/lz/z//ll/lf. Q

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TIS 7 BY (QM/VVM Patented Feb. 2, 1954 2,668,205 MULTPOLE CIRCUIT BREAKER Haddon Heights, N. J.,- assigner to IT-E Circuit Breaker Company, Philadelchia,

Pa., a corporation of Pennsylvania Application ctbe'r 31, 1951, Serial N0. j254,06

Claims; 1

My present invention relates to circuit breakers and more particularly it relates to circuit breakers having more than one pole.

Multi-pole circuit breakers are usually pro'- duced and sold by bolting two or three single pole circuit breakers together. Simultaneous operation of all poles was obtained by rigidly tying all the external handles together causing simultaneous closing or tripping of all poles.

My novel invention provides means to considerably improve both operation and appearance of these multi-pole circuit breakers.

Essentially, each Apole of my new circuit breaker has its own 'mechanism which is controlled to open or close by an integral handle operating all poles simultaneously.

Furthermore, each pole is provided with its own fault current responsive means and provided with a common tripper bar so that the automatic opening in one phase produces the instantaneous opening of the other two phases. More specically, the cradles in each mechanism are coupled together by insulating bars extending through each breaker. The entire cradle unit is latched to a tripping lever at any point, for example, in the case of a three-pole' breaker at the' center pole and in the case of a two-pole breaker at the left pole. The' tripping lever has an insii-lated bar which extends into the other poles o-f the breaker so that thermal and instantaneous tripping can be accomplished either independ ently' or in combination by one or more phases.

In assembling my novel circuit breaker, the pole which has the manual operating Aextension ofthe integral handle may be assembled rst and then work in either direction to 'build up a two or` three pole breaker.

The main object of my present invention is, therefore, the provision of means whereby multie pole circuit breakers can be easily assembled using practically only parts for single pole circuit breakers.

Another object of myl presen-t invention is the provision of means whereby a fault current in any ofthe circuits protected by my novel multipole circuit breaker will open simultaneously all the contacts of my novelI multi-pole circuit breaker;

A further object of my present invention is the provision or" meansy whereby the opening and closing ci all contacts of the multi-pole circuit breaker can be obtained by the operation of a single handle.

The foregoing and many other objects or' my invention will become' apparent in the following Vdescription and drawings in which:

" te is connected by any Figure l is a sectional View of a two-'pole circuit breaker incorporating my novel invention.

Figure 2 is a sectional View taken on line 2-"22 of Figure l, looking in the direction of the arrows.

Figure 3 is a front view of the circuit breaker or" Figure l.

Figure 4 is a sectional View of a three-pole circuit breaker incorporating my novel invention.

Figure 5 is a sectional View taken on line 5-5 of Figure 4, looking in the direction of thearrows.

Figure 6 is a front View of the circuit breaker of Figure 4.

Figure 'Z is another sectional view of the two pole circuit breaker taken on line '1 -l of Figure 2, looking in the direction or the arrows.

Referring now to Figures 1 and 2 showing a two-pole circuit breaker in the open position, housing l! is a shallow box, preferably a plastic insulating molding, having two cover plates ll and l2, one o n each side of housing lil. Cover plates H and l2 canlbe secured to housing il! in any suitable way, for example, by means of bolts and nuts engaging openings I5 in housing I0 and cover plates Il and l2, or rivets engaging the same opening I5.

Referring now to the phase of this circuit breaker having the manual operating means as shown in Figure l, stationary contact assembly 2li consists of a contact button 2!, welded or in any other appropriate way secured to the bent end of a conducting member 25. Member l with contact button 2l is slideably mounted in an appropriately shaped recess 25 of molding I0, that is, member 25 can be slid in place in housing It when cover plate Il is removed. The other end 3!! of conducting member 25 has a central opening 3| threaded inside and engageable by a Screw 35. The line terminal of one phase, not shown, can be secured to the circuit breaker by means of screw and extension 3c of contact member 25. The load terminal of the sarne` phase is secured to the circuit breaker at terminal 31. Terminal 3l `consists of a screw 33 engaging an opening 3s in an angularly shaped conducting member d0. Conducting member lil of rectane guiar cross section is secured to housing lll by means of a screw 4l engaging through an appropriate opening 152 of housing lil a threaded opening i3 in conducting member di?. Conducting memberv til is soldered to thermally responsive member lie and the completed assembly is then drilled and tapped to receive screwY d5. Screw 4 5 is used to adjust the tripping times of each pole oi the' circuit breaker as hereinafter described. The other end ci"v 'thermally responsive member appropriate mea-ns, for

example, soldering to a nexible conductor or pigtail 50. Conducting member 40 is also provided with an integral support 52, consisting of two extensions 53 and 54, one on each side of thermally responsive member 46. Both. extensions 53 and 54 extend beyond thermally responsive member 46 and carry at their farthest end a pin 55. A coil spring 80 around pin '55 has one end 5| against a protruding portion 62 of housing I9 and its other end 63 biases a latch carrying member 65.

Latch carrying member 65 consists of a thin metallic leaf 66 approximately U-shaped having at one end extending arms 61 with openings 68 which are engaged by pin 55 so that member 65 can rotate around pin 55. The other end of member 65 is bent and has a U-shaped portion with aligned openings 59 carrying tripper bar 10. Tripper bar is held in place by a bent nger 1| cut from the metallic leaf 66.

Tripper bar 10 is an insulated bar common to the two phases of the circuit breaker; that is. tripper bar 10 extends from the phase of the circuit breaker now under consideration to the second phase of the same circuit breaker, as hereinafter described.

Trip lever |35 is further provided with an armature 12 which is secured to trip lever 65 by any suitable means, for example, a rivet. Armature 12 is the movable part of the fault current ref sponsive magnet which consists or" a rectangular piece of metal with a central recess 16 to receive thermally responsive member 56 to which it is also secured by means of a rivet. The same rivet that secures armature 12 to trip lever 65 can be used to secure latch 80 to trip lever 55. Thermally responsive member 46 and magnet 15, as is quite evident, are designed to operate at different values of fault currents. For example, when a fault current is relatively small, the

thermally responsive member 46 will operate to open the circuit breaker as hereinafter described. If, on the other hand, the fault current is relatively high, magnet 15 will come into operation before thermally responsive member 46 and open the circuit breaker. This is important in that by this means thermally responsive member 46 is protected against very heavy currents which could permanently distort and damage bimetallic member 46.

Latch 80 carried by trip lever 65 engages a hook-shaped cradle 85 and more precisely latch 80 engages one end 8S of cradle 65. Cradle 85 is pivoted at the other end 01 by means of a pin 89 engaging an opening 89 in cradle 65 and an aligned opening 90 in a boss 9| of molding |0.

It was previously mentioned that screw 45 is used to adjust the tripping time of each pole of the circuit breaker. In fact, since the head of the screw 45 bears against the inner U-shaped pocket 92 of molding i0, any turning of screw 45 'will bend the terminal assembly of the thermally responsive member 46. The thermally responsive member 46 then moves the tripper bar 10 and lever 65 to decrease the amount of latch fbite between latch and cradle end 86. The tripping times are adjusted by means of a screw driver inserted through a hole 93 in molding i0. After adjustment hole 93 is sealed with porcelain or other insulating compound.

Cradle of the rst phase moves together with cradle |85 of the second phase since the two cradles 85 and |55 are connected together by an insulating tie bar 95. Tie bar 95 actually consists of a center insulating sleeve 95 and two lateral insulating sleeves 91 and 98. Central sleeve 96, cylindrical in shape, has two recesses 99 and |00, one at each end of cylinder 96. Lateral sleeves 91 and 98 instead have an axial or longitudinal opening |0| and |02, respectively.

Cradles 85 and |85 both have an opening |03 near the ends 86 and |86, respectively. Each opening |03 is engaged by the cylindrical extension |04 of a cylindrical pin |05. A metallic hollow cylinder |06 is slid on the extension |04 and riveted there. Thus, cradles 85 and |35 are clamped to pins |05 and will move with pins |05. Sleeves 91 and 98 are placed around pins |05, while sleeve 96 is placed around the hollow cylinders |06, thus completely insulating one phase from the other and making at the same time a mechanism strong enough to resist damage produced by repeated opening or closing operations.

Pin |95 on cradle B5, in the case of the twopole circuit breaker, has for its purpose in conjunction with resetting pin |56, the aligning of cradle 85. The cradle 55 is, therefore, positioned on one side by pin |05 bearing against cover and on the other side by the shouldered resetting pin |56 bearing against pad |01 on the molding l0. This construction makes the cradle assembly between the poles more rigid and compensates Ifor the unequal loading on the left cradle 65 by the load on the right cradle |85.

Pigtail 50 connected on one side to thermally responsive member 45 `is connected on the other side to movable contact arm H0. Movable contact arm lill is approximately U-shaped or is shaped like a tuning fork, the lowest part of movable contact member ||0 carrying an electrical contact ||2. The two extensions ||5 of contact arm ||0 can rotate in groove ||8 of handle molding |20. An over center tension spring |25 is connected on one side to movable contact arm I0 through an opening |2'a` in contact arm ||0 and on the other side to cradle 85 through an opening |21 in cradle 65. Cradle B5 is further provided with a pin |30 which engages a slot |3| of a contact kicking member |35. Contact kicking member |35 is pivoted around pin |36 which engages an opening |31 in contact kicking member |35 and an aligned opening, not shown, in molding I0. Contact kicking member |35 is provided with an extension |39 at the end of the contact kicking member |35 opposite that at which it is pivoted.

The function of the contact kicking member |35 is to assist the initial opening operation caused by a fault current; more specifically, it provides a means for kicking the movable contact away from the complementary contact when the spring has been moved over center during automatic opening. In other words, kicker |35 prevents contact ||2 from sticking to the stationary contact 2| at fault currents, thus preventing welding of the contacts.

Manual operating handle molding |20 operates simultaneously both contacts of the two phase circuit breaker under consideration. It has, therefore, a single handle with an integral axially extending member |4|. This axial member ill! has two pins |42 and |43, one on each side of axial member Ml, both integral parts of molding Axial member has two pairs of fulcri |18 and |53 of which, as previously explained, fulcruin HB is for movable contact member HQ, while fulcrum is for movable contact member of the second phase of the two-phase circuit breaker under consideration. Molding is also provided with two extensions |54, one onl each side of fulcrum ||8 operable to engage a reset pin |56 carried by cradle 85 in an appropriate opening |51 located between pin I3@ and spring opening |21v in cradle 85.

Referring' now more specifically to Figures 2 and '7 and comparing the cross-sectional drawingY of Figure '1 with that of Figure l, it is there seen that the two phases use practically the same parts except in their operating mechanisms both automatic and manual.

To be more specific, the second phase fault current responsive means (Figure 7) consists of a thermally responsive member 246 soldered to an angle conducting member 249, which carries at its other end one terminal 231l of the second phase of the two-pole circuit breaker. A screw 245 engaging the assembly 240--246 and bearing against the inner U-shaped pocket 282 of molding IG is used to adjust the tripping times of each. pole of the circuit breal-:er as previously described.

The free end of thermally responsive member 246 is connected to pigtail or exible conductor 250. Thermally responsive member 245 further carries rigidly secured to it an approximately U-shaped metallic member 215. Metallic member 215 when current flows through thermally responsive member 246 constitutes the magnet for the magnetic fault current responsive means.

A leaf spring 265 is riveted to thermally responsive member 246 near the end at which thermally responsive member 24S is secured to angle 240. Leaf spring 265 extends beyond the free end of thermally responsive member 246 and to the other side of thermally responsive member 246. On its free end leaf spring 265 carries an insulating button 255. Leaf spring 265` also carries the armature 212 for magnet 215. Armature 212 is secured to leaf spring 265 by any appropriate means, for example, a rivet.

.As it is evident from this description, no latch is provided for this second section phase, that is, only the rst phase or the phase which has the manual operating means is provided with a latch` 8G for latching cradle 85.

When a fault' occurs in the second phase,

either thermally responsive member 245 ormagnet 215 will operate and will engage and move tripper bar 10 in such a direction as to unlatch cradle 85 .from latch 8|) of the first phase, but since cradle of the second phase moves together with cradle 85 of the iirst phase as pree.

viously described, cradle |25 will rotate together with cradle 85 around its pivot pin 335.

This movement around pivot point 336' will carry spring 325 of the second phase to the left as shown in Figure 7) of movable contact arm 3H), thus opening the electrical contact between movable contact 3|2 and stationary contact 22|.

The second phase is also provided with a contact kicking assembly 335 which operates in the l same manner as the contact kicking assembly of the first phase.

Each phase is further provided with an arc extinguishing chamber' 32S having a plurality of conducting are extinguishing plates 32. One of the two chambers 32E) is located between the stationary contact 2|` and movable contact H2, while the other chamber 30|] of the second phase is located between the corresponding contacts 22| and 3|.2 of the secondphase. As above-mentioned, all the other parts of this secondA phase are the same as those used in the first phase.

When the two circuits protected by this twophase circuit breaker are to be closed, handle |49 is rotated from right to left of Figure 1. When handle is rotated in this direction, the two: contact arms ||0 and 3io rotate around fulcri ||8 and |50, respectively, to engage their stationary contacts 2| for the rst phase and 22| for the second phase. The closing movement is actually a snap action movement in that the two contact arms im and BIB will move to close the two phases only after springs |25 and 325, respectively, have gone over center with respect to contact arms Il@ and 3M), thus biasing the two contact arms HQ and 3||l against their respective stationary contacts 2| for the rst phase and 22| for the second phase. Since the two contact arms Il@ and 3H) are biased. toward the stationary contacts 2| in one phase and 22| in the other phase, the two contacts H0 and 3H! will snap closed at a relatively high speed. thus preventing an arc from being formed or better from being prolonged between movable contacts ||2 and SI2 on one side and stationary contacts 2| and 22|. When a fault current of a certain magnitude develops in one of the circuits, proteced by this two phase circuit breaker, and for example, when a fault current develops in the first phase of a circuit breaker, depending on the magnitude of this fault current, either the 'thermally responsive member 46 or the magnet 15 wili operate and will move leaf member against the bias of coil spring G to release latch t@ from engagement with extension 86 of cradle 85. Cradle 25 is now free to rotate around its pivot pin |56 bringing with it during its rotation spring |25 until spring |25 is at the right of contact member Htl. When spring |25 is at the right of contact member HU, contact member |40 is biased away from stationary contact 2| and will therefore break the electrical contact between movable contact i |2 and stationary contact 2|. At the same time that spring |25 moved by cradle 85 goes over center, pin |35 also moved by cradle slides from one dimension in slot l-ti to the other dimension of slot |3| of contact kicking member |35, thus rotating contact kicking member S35 around its pivotv |36 to kick the Contact arm l l d and prevent the sticking of contact ||2 to 2i.

The action of spring |25 provides an excellent quick-break action therefore, the arc between contacts H2 and 2| will last for a very small interval of time. Since the second phase cradle |85 is connected by means of tie bar 95 tothe rst phase, the movement oi cradle 85 to open contacts l2 and 2i is accompanied by a similar movement or" cradle |25 of the second phase to open the corresponding second phase contacts 312 and 22 the opening operation o?? the second phase contacts 3&2 and 22! and the opening operation of the second phase will be exactly the same as the one described above in connection with the irst phase.

If, on the other hand. a fault current is deveioped in the second phase of the circuits protected by this circuit breaker, the second phase bi-metal member 25S or the second phase magnet 2?'5 will move tripper bar 15 in such a direcas to produce the unlatching between latch and extension of cradle S5, that is, a fault current in the second circuit will operate a: fault current responsive means in the second phase which' by means of a common tripper bar i9 will freeI cradle 85 of the first phase from engagement with latch 86. As above described, when cradle 85 moves to open contacts II2 and 2i, a similar action is produced for the second phase since the two cradles 85 and |65 of the first and second phase, respectively, are tied together by tie bar 95. By this means dangerous single phasing is avoided, that is, at no time when a fault occurs will only one of the two circuits remain closed. A fault in any of these two circuits will produce immediate opening of both circuits. As for its manual opening operation, a movement of handle M from the left to the right, Figure 1, will produce movements of spring E25, spring 325, contact arm IIl and Contact arm 3I similar but in opposite direction to those described in connection with the closing procedure of this circuit breaker. It must be underlined thatwhen the circuit breaker is manually opened, a quick break action is also obtained in that at no time will spring 25 rotate around a ulcrum produced by cradle S5 and boss 65 of housing I5, but a clearance will always be present between spring I on one side and cradle 95 and boss 9i on the other. A similar situation exists ior the respective elements of the second phase of the circuit breaker.

Referring now to Figures 4, 5 and (l showing the three-pole embodiment of my present invention, all parts for each of the three phases are the same as those described for the two-pole circuit breaker except for the elements common to all three poles.

In fact, handle molding 525 consists of a handle 549 and in a direction perpendicular to said handle 549 two extensions 5M similarly shaped, one on each side of handle 545. At the ends of these extensions 54E are two cylindrical extensions 543 which by engaging appropriate openings 544 of cover plates 4H and 4l?. make possible the rotational movement of molding 525 around cylindrical extensions 543. Members 54I actually constitute a single piece having three pairs of grooves SI5 in which arms 5I5 of movable contact arms 5I9 can rotate.

The central phase in the three-pole circuit breaker corresponds to the first phase of the twopole circuit breaker above described in that it is the only phase provided with a latch 459 for its cradle 485. ing a leaf spring 255 has, similarly to the first phase of the two-pole circuit breaker, a metallic lealc member 455 (corresponding to member oi Figure l) which at its end 459 carries the trip'- per bar M5.

Tripper bar 419 can be operated by the center phase now under consideration by meam of the thermally responsive means 945 or, should the fault current be very hig i, by means of magnet 415 secured to thermally responsive member 445 and armature 412 secured to leaf member 555. Leaf member 465 is biased by means of coil spring 451 on pin 455.

Here tripper bar 419 extends through opening 462 in phase separating walls 465 of molding 4I() into the two lateral phases. Tripper bar 410 extends sufficiently so that any one of the two leaf springs 555 operated by thermally responsive members (not shown) similar to members 246, or magnets (not shown) similar to magnets 215 of Figure 7, will engage tripper bar 41o and unlatch the central phase latch 455 from engagement with the central cradle 455.

Central cradle 4-35 now free from engagement with latch 489 will rotate around its pivot 439.

This center phase instead of haw .r

Rotation of central cradle 485 around pivot 438 will produce similar rotations in the other two cradles 585 since all cradles are connected for simultaneous movement by tie bar 495.

Tie bar 495 extending through openings 5I3 of phase separating walls 466 into the other two phases, actually consists of two center insulating sleeves 495 and two lateral insulating sleeves 491 and 498. Central sleeves 496, cylindrical in shape, have two recesses 499 and 599 one on each end of insulating cylinders 496. Lateral sleeves 491 and 499 instead have axial or longitudinal openings 59| and 592, respectively.

Cradles

435 and 585 all have an opening 593 near the ends 485 and 586, respectively. Each opening 593 is engaged by a reduced diameter portion 594 of a cylindrical pin 595. A metallic hollow cylinder 566 is slid on the extension 594 and riveted there. Thus, cradles 495 and 535 are clamped to pins 595 and will move with pins 595.

Sleeves 492 and 498 are placed around hollow cylinders 595 of the rst phase (left phase in Figure 5), and pin 595 of the third phase (right phase in Figure 5). Each sleeve 495, on the other hand, is placed on the hollow cylinder 556 of one cradle, as for example, cradle 495, and on the pin 595 of the adjoining cradle, as for example, cradle 555 of the right phase. It may also be said that pin 595 and hollow cylinder 595 are one riveted assembly which provides projection for mounting sleeves 496, 49'# and 498.

Sleeves 491 and 498 serve also to position and retain the current carrying braid 450.

The use of sleeves 496, 491 and 498 completely insulates one phase from the others and makes the mechanism strong enough to resist damage produced by repeated opening or closing operations. Sleeves 491 and 498 and pins 565 are kept in place by the two cover plates 4I I and 4I2, one on each side of the three-pole circuit breaker.

As above mentioned, rotation of central cradle 485 produces, through the bar 495, similal` rotations in the other two cradles 565.

Rotation of

cradles

485 and 585 brings the springs 525 and 125, respectively, overcenter with respect to the movable contact arms 5 I Il and "H9, respectively, thus opening contacts 42| and, 5I2 of the center phase, and also the contacts (not shown) of the other two phases.

At the same time, the three contact kicking members 535 pivoted around pin 536 and provided with an extension 539 are moved by

cradles

485 and 585 through a pin 530 carried by

cradles

485 and 585 and slots 53| in contact kicking member 595 to kick contact arms 5IIl and 1li) after springs 525 and have gone over center, thus prying the contacts open should they stick to each other.

For reclosing after an automatic opening, the center phase cradle 485 is provided with an opening 5B1 having a reset pin 586 so that extensions 534 of molding 520 can engage this reset pin 589 and move the cradle 485 back to the original position by rotation of the handle 549 to the full open position (shown in Figure 4). Since the

cradles

485 and 585 are tied together through tie bar 495 also, the other two cradles 585 will return to their original position. If now the circuit breaker is manually closed by rotation of handle 540 from right to left (Figure 4), the circuit breaker is again ready to automatically open at fault currents.

When the circuit breaker is to be manually opened, handle 540 is moved from left to right 9 (Figure i). `Movement of handle V540 produces rotation in cylindrical member '541 around its axis, with the `consequent displacement 'of contact arms |0 and lll] with respect Vto springs 525 and 125, respectively, until springs A525 and 125 are over center. When springs 525 and 125 are over center, a force directed to the contact open position is produced on the contact arms 5|'0 and TIG, thus snapping the contacts 5H) and 'H0 to the open position.

Here the

cradles

485 and 585 are so shaped in the region directly facing springs 521-5 and 125, respectively, that a clearance exists .at all times between springs 525 and 725 and that portion of

cradles

485 and 585 that faces springs 525 and 125, respectively. It is clear that at 'no time during the initial manual opening operation will springs 525 and '125 hit the portion of

cradles

485 and 585 directly facing springs k525 and 125, to produce harmful prying of contacts before springs 525 and T25 become operative rto move the movable contact arms 510 and H0 to the open position.

The closing operation is similar to the above described manual opening operation with all movements occurring in the opposite direction.

In the foregoing I have described my 'invention 'solely in connection with speciiic illustrative embodiments thereof. Since many variations and modications of my invention will now.

be`obvious to those skilled in the art, l prefer to be bound not by the specic disclosures herein contained but only by the appended claims.

I claim:

l. In a multi-pole circuit breaker, a plurality of xed contacts, a plurality of lmovable contact arms carrying movable contacts, said arms having a circuit closed position in which their movable contacts engage said fixed contacts and a circuit open position in which said contacts are disengaged, a plurality of U-shaped cradles pivotally mounted at one end, a tie bar, said tie bar comprising pins and insulating sleeves, said pins engaging said cradles, said insulating sleeves rigidly securing said pins to each other and connecting said cradles for simultaneous motion, a

plurality of springs, one end of said springs being secured to said movable arms and the opposite end of said springs being secured to said cradles at the apex of the U-shaped cradles, a pivotally mounted operating handle having a manually operable end on one side of the pivot mounting and having a plurality of notches on the opposite end of the pvot mounting, said movable contact arms being pivotally mounted in said notches and extending substantially in the longitudinal direction of said handle, with said movable contacts on the end opposite the pivotal mounting' of said arms, the notches in said handle being on one side of said springs when said handle is in closed position so that said springs apply a closing force on said arms for operating said arms to circuit closed position, and the notches on said handle being on the opposite side of said springs when said handle is in open position so that said springs apply an opening force on said arms for operating said arms to circuit open position, and a plurality of fault current responsive means.

2. In a multi-pole circuit breaker, a plurality of fixed contacts, a plurality of movable contact arms carrying movable contacts, said arms having a circuit closed position in which their movable contacts engage said fixed contacts and a circuit open position in which said contacts are disengaged, a plurality of U-shaped cradles, one of said cradles having one end latched and pivotallymounted at its opposite end, the remaining cradles being only pivotally mounted at one end, a tie bar, said tie bar comprising pins and insulating sleeves, said `pins 'engaging said cradles, said insulating sleeves rigidly securing said pins to each other vand connecting said cradles `for simultaneous motion, ra plurality of springs, Vone end of said springs being secured to said movable arms Yand the opposite end of said springs being secured to said cradles at the apex of the U- shaped cradles, a pivotally mounted operating handle having a manually operable end on one side of the pivot mounting and having a 'plurality of Vnotches on the opposite end of the pivot mounting, said movable contact 'arms being pivotally mounted in said notches and extending substantially in the longitudinal direction of said handle, with said movable contacts on the 'end opposite the pivotal 'mounting of said arms', the notches in said handle being on one side of said springs when said handle is in closed 'position so that said rsprings apply a closing force on said arms for operating said arms to circuit closed position, and the notches on said handle being on the opposite side of said springs when said handle is in open position 'so that said springs apply an opening force on said .arms for operating said arms to circuit open position', a .plurality of fault current responsive means, 'one of said means havinga latch. forlatching the said cradle, a tripper bar, said tripper bar :being secured to said latch carrying fault current responsive means but being operable by the other fault current responsive means, and an insulating housing.

3. in a multi-pole circuit breaker, a plurality of fixed contacts, a plurality of movable contact arms carrying movable contacts, said arms having a circuit closed position in which their 'movable contacts engage said fixed contacts and a circuit open position in which said contacts are disengaged, a plurality of U-shaped cradles, one of said cradles having one end latched and pivotally mounted at its opposite end, the remaining cradles being only pivotally mounted at one end, a tie bar, said tie bar comprising pins and insulating sleeves, said pins engaging said cradles, said insulating sleeves rigidly securing said pins to each other and connecting said cradles for simultaneous motion, a plurality of springs, one end of said springs being secured to said movable arms and the opposite end of said springs being secured to said cradles at the apex of the U- shaped cradles, a pivotally mounted operating handle having a manually operable end on one side of the pivot mounting and having a plurality of notches on the opposite end of the pivot mounting, said movable contact arms being pivotally mounted in said notches and extending substantially in the longitudinal direction of said handle, with said movable contacts on the end opposite the pivotal mounting of said arms, the notches in said handle being on one side of said springs when said handle is in closed position so that said springs apply a closing force on said arms for operating said arms to circuit closed position, and the notches on said handle being on the opposite side of said springs when said handle is in open position so that said springs apply an opening force on said arms for operating said arms to circuit open position, a plurality of fault current responsive means, one of said means having a latch for latching the said cradle, a tripper bar, said tripper bar being secured to said latch carrying fault current responsive means but being operable by the other fault current responsive means.

aeeaeos 4. In a multi-pole circuit breaker, a plurality of xed contacts, a plurality of movable contact arms carrying movable contacts, said contact arms having a circuit closed position in which their movable contacts engage said xed contacts and a circuit open position in which said contacts are disengaged, a plurality of U-shaped cradles, a tie bar, said tie bar comprising pins and insulating sleeves, said pins engaging said cradles, said insulating sleeves rigidly securing said pins to each other and connecting said cradles for simultaneous motion, a plurality of springs, one end of said springs being secured to said movable arms and the opposite ends of said springs being secured to said cradles at the apex of the U-shaped cradles, manually operable means, said manually operable means pivotally mounted and having manually operable end on one side of the pivot mounting and having a plurality of notches on the opposite end of said pivot mounting, said movable contact arm being pivotally mounted in said notches and extending substantially in the longitudinal direction of said manually operable means with said movable contacts on the end opposite said pivotal mounting of said contact arms, the notches in said manually operable means being on one side of said springs when said manually operable means is in said closed position so that said springs apply a closing force on said contact arms for operating said contact arms to circuit closed position, said notches on said manually operable means being on the opposite side of said springs When said manually operable means is in open position so that said springs apply an opening force on said contact arms for operating said contact arms to circuit open position, a plurality of fault currentresponsive means, one of said means having a latch for latching one of said cradles, a tripper bar, said tripper bar being secured to said latch carrying fault current responsive means, said tripper bar being secured to said fault current responsive means which do not have a latch, said fault current responsive means which do not have a latch effective to cause disengagement between said one cradle and said latch carrying fault current responsive means through said tripper bar.

5. In a multi-pole circuit breaker, a plurality of fixed contacts, a plurality of movable contact arms carrying movable contacts, said arms having a circuit closed position in which their movable contacts engage said xed contacts and a circuit open position in which said contacts are disengaged, cradle means for at least one pole of said multi-pole circuit breaker, a fault current responsive means for each pole of said circuit breaker, a fault current responsive means associated with said cradle means for one pole of said circuit breaker having a latch for latching said cradle means, a tripper bar, said tripper bar being secured to said latch carrying fault current responsive means, said fault current responsive means which do not contain a latch keyed to operate said tripper bar.

FELIX E. MYERS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,343,612 Frank et al Mar. 7, 1944 2,487,637 Cole et al. Nov. 8, 1949 2,527,997 Besag et al Oct. 31, 1950 2,542,530 Jeirey Feb. 20, 1951