US2047739A - Circuit interrupter - Google Patents

Description

July 14, 1936. H J. UNGAL 2,047,739

CIRCUIT INTERRUPTER 4 Filed March 25, 1932 4 SheelZS--Sheel 2 INVENTOR July 14, 1936.. H J, UNGAL 2,047,739 l C IRCU T INTERRUPTER Filed Mroh 25, 1932 4 sheets-sheet s INVENTOR July 14, QS. H. L !NGAL 2,047,739

4 CIRCUIT INTERRUPTER Filed March 23, 1952 l 4 sheets-sheet 4 92,1%/ S ES'S INVENTGR Har/y J i /ngc/ Patented .hay 14, 193s UNITED STATES PATENT OFFICEl Application March 23, 1932, Serial No. 600,624

31 Claims.

My invention relates to circuit breakers and particularly to circuit breakers of the type in which the breaker-operating means is manually operable to open or to close the circuit, and is automatically operable to open thecircuit and to prevent the closing of the circuit upon the occurrence ofshort-circuit or overload conditions.

One object of my invention is to provide a circuit breaker having an improved trip mechanism Acapable of opening the breaker after a predetermined time interval in response to an overload in the controlled circuit, and capable of opening the breaker immediately upon the occurrence of a short-circuit condition in the controlled circuit.

I Another object of my invention is to provide an improved conducting' means for -a circuit- 4breaker trip device having a thermally responsive and a magnetically responsive element; the improved conducting means being capable of serving the double function of heating the thermally responsive element and magnetizing the magnetically responsive 4or instantaneous trip element. l

A further object of my invention is to pro- `vide an improved supporting means for circuit breaker trip devices whereby the thermally responsive element and the magnetically responsive element are both supported by a single frame member.

A further object of my invention is to provide A sun :uriner object or my invention is to provide an improved means for s'lidably and piv- Y otally mounting the latch for circuit breaker trip devices which are resettable by means associated with the operating handle. 'I'he slidable mounting for the latchv making it possible to bias the various elements of the ytripiievice, including' the latch itself, to the latched position, or, in other words. making possible a trip device which is entirely automatically mettable. And. what 'is equally important, the slidle mounting of the latch permits the resetting means to moveto a magnetically re- (Cl. 20o-88) the latched position without in any way disturbing the automatic resetting feature of the trip device.

'I'he principal field for immediate application ofmy invention is irl/connection with circuit 5 breakers for controlling lighting and distribu-v tion feeder circuits, and I shall hereinafter describe an embodiment of my invention as applied to such circuit breakers, without, however,in any way intending to restrict the scope of my inven- 10. tion, except as indicated in the appended claims.

In this embodiment of my invention, I provide a plurality of switch members and a plurality of contact members for opening a plurality of poles.

In addition, I provide a manually operable mech- 15 anism for opening and closing the breaker contacts with a snap action, an insulating base upon which the structure is assembled, an arc extinguishing device for each pole, a means for biasing each of the switch members to the open 20 position, a releasable restraining means for holding all of the switch members closed, and a unitary, removable trip device for releasing the restraining means in 'response to a predetermined electrical condition in any one pole, thereby open- 25 ing all of the poles of the breaker; the veieitsing [means being operable to open the breaker regardless of the position of the operating hand-ie.

The features of my invention which believe to be new are particularly pointed out in appended claims, and for a full understandingof the principles of the invention, reference may be had to the accompanying drawings, in which Figure 1'is a plan view of a three-pole circuit breaker embodying the principal elements of my invention; the cover has been cut away to show part of the breaker mechanism and has been entirely removed from the trip structure.

Fig. 2 is a sectional view on the line II-lI of Fig. l; certain 0f the parts are shown in elevation to more clearly illustrate the structural features involved. f

Fig. 3 is a perspective view oi the unitary trip-structureusedin this embodiment of my invention.

a Fig. 4 is a fragmentary Perspective view showing a part of one ofthe individual trip mechanismsincorporated into the trip structure shown in Fig. 3. j '5o Fig. 5 is a sectional .view on the line V-V of Fig. 4. v n Y V1"!8. 8 is an expandeddetail view of one of the integral vconducting strips used in the trip structureshownin-1"ig.3. ,'56

Fig.'iisaperspectiveviewofthe'fra meof` shown in Fig. 4; and I 10 are fragmentary views show-I parts' of the circuit breaker opmechanism in the closed, open, and tripped positions."--resp o ctively; one side of the frame has been cutaway-to more clearly illus trate the structuraidetails involved.

Referring to the drawings, the base I is of molded insulatingmaterial and. has mounted thereon the terminal contacts 3 and l. the unitary trip structure 1, the circuit breaker operating mechanism s which has associated therewith the assembly of the switch members il,'and the arc extinguishers Il, which have integral therewith the main stationary contact I5 and the auxiliary stationary contact I1. The switchv members II and the stationary contacts II and I1 combine to form a plurality of poles. Each of the poles is insulated from the adjacent pole by means of one of the insulating barriers I 9 which are molded in the base I. These insulatingbarriers I9 align with similar barriers (not shown) in the cover 2i which is likewise of molded insulating material. The operating handle 23 which is rigidly aflixed to the switch operating mechanism 9 is also of molded insulating material, and it has a portion 25 which projects through a suitable opening 21 in the cover 2i. 'I'he unitary trlpstructure 1 has a base 28 of insulating material and a cover also of insulatingmaterial.' The unitary trip structure 1 lits in a suitable recess in the insulating vbase I and is fastened therein, as will be described in somedetail later, through the agency of suitable screw fastenings.

'I'he electrical circuit for each of the poles is substantially the same. Beginning with the termina] contact I, the current passes successively `ing contact 3i is pivotally fastened to the iron frame 31 by'a pivot pin I! extending through two holas placed in opposite sides of the frame 31. Two cotr pins 4I prevent the pivot pin 38 from moving out of position. 'I'he ilexible shunt 3l is riveted to the moving contact )i by the rivets 4l, and it is provided with a terminal portion 45 on the free end for engaging the corresponding terminal 35 oi the trip structure 1; the screws 41 which engage suitable threaded recesses 49 in the base I being provided to releasably connect those terminals.

Each of the moving `contacts II has a portion II extending downward into the frame (Fig. 2).

'I'his portion BI is engaged by the free end of a iiat spring Il: the other end of the spring I3 is rigidly fastened to the frame I1 by rivets Il. A square insulating bar 61 extends across all three poles of the breaker.v This bar is rigidly ailixed to the lower part of each of the switch members ii by means of an iron strap B9 which loops about the bar 51 and hasprojectlons (not shown) which extend through suitable openings l in the frame 31 andare therein clinched. This bar' l1 serves to rigidly connect all of the switch members il, and thereby makes itpossible to' operaieall three Aof the switch members from a singlesoperating mechanism. Also, this bar provides-ameans wherebyall of the poles of the breaker are opened and closed simultaneously; thus an overload or a short circuit condition in v the circuit controiledbyanyone ofthe poles will,throughthetrlp1,causeailof' the poles of the breaker to open.

The main stationary contact Il and the engaging portion 'Il of the moving contact Il arolo composed of silver in order to improve the cur.- rent-carrying qualities. The auxiliarly stationary contact I1 and its portion i! are composed of an are resisting alloy of tungsten and silver; the proportions -being 60% of. the il former and 40% of the latter. I prefer to use arc resisting material for these contact surfaces in order to reduce to a minimum the injurious effects of the arc which is established therebetween during the operation of the breaker. 20

The arc extinguishers I3 which I prefer to use with my invention are of the spaced-plate type which comprises a stack of compositefplates, each having an edge portion of magnetic material and a central portion of non-magnetic, material. 25 Each composite plate is insulated from the ad- `jacent plate and has .a slot therein. The extinguishers areA disposed adjacent tothe arc path, the slots being o f substantially the sameoutline as the moving contacts, and upon the establishment-of the arc, due to the altering of the magnetic field adjacent to the arc path, force the arc to move into the spaces between the plates where .it is rotated by suitable means associated with the extinguisher until it is cooled and extin- 85 guished.

The details of construction and the principles of operation of this preferred type of arc extinguisher are completely described in the application of M. W. Brainard, Serial was illed February 16, 1932, d which is also assigned to the assignee oi' this invention.

As previously pointed out, each of the arc extinguishers I3 is separated from the adjacent arc extinguisher by the insulating barriers Il, this construction gives an increased margin of safety while interrupting heavy arc currents by reducing the possibility of ilash-over between adjacent poles.

The operating mechanism 9 comprises. in general, a U-shaped base 83, a pair of toggle links 85 and 61 for engaging the assembly of the switch members II, a trigger I8 for releasably restraining the .toggle links 85 and 81 in an operative fposition, a biiurcated operating lever 1I, springs 13 for connecting the operating lever 1I to the knee of' toggle links, and the operating handle 2l. The U-shaped base 83 is fastened to the insulating base I of the circuit breaker proper by means of four screws 16, two at either end, and. in ad- 60 dition. it has a downwardly projecting portion 15 (li'ig.` 2) which is engaged by the central screw 41; the mechanism l is thus electrically connected to the circuit of the central pole Iof the breaker, the reason for this will be brought out in a 55 subsequent paragraph.

A pivot pin -11 extends through suitable aligned openings in the U-shaped base 68 and engages the frames? of the central switch member Il. This pin 11 provides a pivot poInt for the assem- 70 'bly of switch members H. an of which are mechanically tied together by the insulating bar 51. Other holes are provided in the base G8 for the reception of the pivot pins 'iS-one on either side of the U--which provide pivot points for the bi- 593,236.' which 404 fumdopmanglev'er'n. 'meloni-mwah respecttothebase I) ofthetogglelinkllispivotaily connected to the trame l1 of the central switch member II by the pin II, the pin-II serv-v ing to connect the operating mechanism I and the assembly of switch members II. Theother end of the toggle link t1 is pivoted to one end oi f thesecondtoggielinkll bymeansof theknee pivot pin 82. 'Ihe knee pivot pin Il has means associated therewith for engaging one end of each oi.' the operating springs 12, one on either end, the other end of the operating springs being connected to the operating handle 22. The trigger Il which is pivoted about pin Il provides a releasably restraining means tor holding the gaged by the latch l1 associated with the trip structure 1.

As previously pointed out, the trip structure 1 is a unitary device entirely assembled upon its own insulating base 2l and completely removable fromthe breaker; the screws l1 and the bolts 9! with their associated nut Ill being utilized to mount the trip structure onthe base I and to make the necessary electrical connections. 'I'he trip structure 1 includes a thermally responsive element III and a magnetically responsive element for each of the three poles. 'I'he three conducting bars or strips Ill-one of `which is associated with each oi the poles of the breakershave the quadruple function of providing terminals for the trip structure 1, of providing ener- Y gizing means for each of the magnetically re sponsive elements, of providingheater means for the thermally responsive elements IUI, and for providing a supporting means for the entire trip structure.

Each oi' the thermally responsive elements IIII is composed of bimetallic material. Four holes' are provided therein for engaging the rivets |I2 which fasten each of the bimetallic elements Ill to one oi' the conducting members |03. 'Ihe sides of the thermally responsive element IUI taper toward each other in order to reduce the amount of bimetallic material required, and in order to secure a more uniform distribution of the bending stresses-the maximum mass being positioned 'neart the hottest portion of the heater.

Fig. 6 shows a detailed view of one of the conducting strips lll before being bent to its reexed shape. It will,be noted that openings Ilil and |I1 are provided in the terminals 3l and 28 for engaging the bolts QI and the screws 41, respectively. Also, there are four holes Il! for engaging the rivets |I2 which provide means for iastening the conducting strip III to the thermally responsive element III and to the frame I II of each of the individual trip devices.

As shown, particularlyin Figs. 2, 4, and 5. the conducting strips Il! in the assembled structure are bent so as to iorm two renexed bends on loops III andV III. 'The straight part III o! the con-.

ducting strip |02 which connects 'the terminal It and the loop Illy is utilied for energizing the responsive device whiiethe loopy llt' ment I 3B of the pin I 2l provides a biasingmeans trip structure'.

is utilized as. a heater for the thermally responsive element III. The portion of the conducting strip |03 which is used in forming the loop |.I3 is tapered so as to givea conducting section of gradually `increasing electrical lresistance; the 5 h point ot the maximum resistance and the point of the maximum heating are located adjacent to the base oi' the thermally responsive element IDI (Fig. 5). The heating is thus concentrated at the point of maximum eii'ectiveness. .The por- 10 tion IIB of the conducting strip |03 which is utilizedas an energizing means for the magnetically responsive element is not of reduced section and does notV heat appreciably while carrying the rated current ci the breaker.` The terminal 36 15 of the conducting strip |02 which engages the bolt I! has been bent back upon itselivto provide a better contact.

Each of the individual trip devices are built up around the conducting strip |03 and the 20 frame Each of the frames which are 4oi' non-magnetic material is substantially U- shaped and has suitable openings IM through whichthe rivets ||2 pass. In addition to the openings IM, two other openings lllvare pro- 25 vided in the body of the U. The openings ||8 provide means whereby the mounting screws I I1 which extend through the base 2! may engage and position the iron core member I I9, a suitable threaded opening |20 being provided therein. 30

Each oi the individual trip devicesis thus rigidly fastened to the base 28, the conducting strip `lili providing terminals and supporting means for the entire structure. A cut portion |23 is provided in the core member Il! to permit the 35 passage oi.' the portion IIS of the conducting strip |03. A portion |25 extends outwardly from the top of the frame III and has a hole |21 therein. This hole |21 permits the passage oi a pin |28 which is fastened to the moving amature lil. The moving armature III is of a magnetic material such as iron and has substantially the same overall dimensions as the core member IIS. v A spring |23 which engages a suitable enlargefor releasably holdlngthe armature I2| against the-lower side of the projecting portion |25 oi the frame III, the core member IIS being sumciently energized upon the occurrence of a short circuit or heavy overload condition to attract the armature |3| against the bias of the spring |33. A thin strip of non-magnetic material |21 is interposed between the pole piece III and the armature III to prevent any sticking of the armature which might result' from the residual 55 l magnetism in the two members.

A common trip bar Ill oi' molded insulating material which is actuable by all of the individual trip devices is provided. AThis bar |39 has two 1 rearwardly extending arms I 4| for engaging the to pivot pins ill which project through suitable openings in the supporting members Ill.' The j supporting members Il! are fastened'to the base 2l by suitablemeans (not shown). A second pro'- 'iecting portion |41 of insulating material (Figs. 65

2 and 3) extends downwardly from the trip bar III and through the agency o! a suitable recess. engages a compression spring Il! which biases the trip bar inwardly toward the base 2l of the 70 A depression I having three cut out portions Illls molded into the trip bar In. Escher these cut out portions III is engaged by one of the pins |20 associated with Keach of the individual moving armatures III. An enlargement |81 on 75 vme nendo: en of the pms 'm prevents the disent of the trip bar therefrom Three screws |99 extend through suitable openings in It will befnoted that the tripping forces sup' plied by the magnetically responsive elements and the tripping forces supplied by the thermally responsive elements have different lines of action. In fact the lines of action are degrees apartthe amature |3| pulling downwardly (Fig. 3) and the bimetal |9| pushing outwardly-and the design of the trip bar-|39 is auch that these two sets of forces are caused to move the bar in the same direction.) 'I'his arrangement is most eifectlve for securing a trip device oi.' small dimensionsit being possible to position the various trip elements so as to most effectively utilize the available space without regard to the line of action of the tripping forces supplied by those elements. A

The trip latch 91 which engages the end of the trigger 99 is slidably pivoted about a pin |9| which extends through suitable openings in two brackets |93 which are alxed to the trip base 29 by rivets |99. The free end |61 of the latch 91 projects through a suitable opening |99 in the trip base 29 and engages theitrip bar through the agency of a projecting metallic member |1| which is embedded in the trip bar proper. The latch 91 has two slots |13 for slidably engaging the pivot pin |9|. A spring |65 exerts a force which prevents the slots |13 from disengaging the pivot pin |9|, and, in addition, the spring |99 biases the latch 91 in a counter-'clockwise direction (Fig. 2). The movement of the latch 91 in a counter-clockwise direction is limited by the projection |19 which extends inwardly from one of the bracket arms |63. when the trigger 69 Iis in the operative position, that is, when the end is restrained by the latch 91, the latch is biased in a clockwise direction due to the relatively large force transmitted by the trigger. This force is balanced by the trip bar |39 which, through its projecting member |1|, releasably engages the free end |61 of the latch 91 and prevents it from turning under the biasing action of the trigger 99.

The insulating cover 39 of the trip structure 1 is held in position by two screws |11 which extend through suitable openings therein and engage two threaded holes |19 on the bracket mem- `ber |45. The insulating cover 2i for the breaker proper is retained in position by four screws |8| which engage threaded openings |83 in the insulating base Openings |95 are provided in the insulating base I for the reception of mounting screws (not shown).

Referring particularly tc Figs. 2 and 8, wherein the circuit breaker of my invention is shown in the closed position, it be noted that the knee of the toggle links 9E and 91 is in the overcenter locked position. Thus, the contacts i9 and 9| are held against each other with a substantially uniform contact pressure maintained by the springs 93. v y

To open the contacts manually, the operating handle 23 is moved clockwise about its pivot 15 (Fig. 8)V `whereupon the springs 19 exert a force having a component tending to move the knee pivot pin v330i the toggle mechanism toward the baseV 29 of the trip device, or out of toggle.l At a certain point, this component of force exerted by the springs 13 is sufllcient to cause the toggle tobreak andmove the switchmembe'rs clockwiseaboutthepinILthussepmtingthecontacts. Thevariouspartsofthemechanismaxe thendispooedasshowninFigJ. Themotionot Vthe central switch member is transmitted to the operating springs connected at their knee makes it possible to open-and close the breaker contacts with a snap action. The proportions of 15" the moving contact 3| are such that'the circuit is ilrst made and iinally interrupted through the auxiliary stationary contact I1 and the tip 92 of the moving contact 3|. When the breaker is in the fully closed position, the auxiliary s'ta- 99 tionary contact |1 ds not engage the moving contact 3|.

WhenA the breaker is in the closed position and an overload comes on the circuit controlled by any one of the poles, the heater portion ||3 25 of the conducting strip |93 lis heated. 'Ihe bimetal element |9| is in intimate contact'with this heater portion ||3 and immediately begins to deflect away from the base 29 of the vtrip structure. If the overload continues for a suf- 30.'

ilcient length of time, the bimetal element |9|'I engages the screw |59 and begins to move the a predetermined time delay, the trip bar |39 has trip bar |39 against its biasing spring |49. After been moved a, sumcient distance. to disengage 35 the projection |1| from the free end |81 of the latch 91. The latch 91 is then free to rotate clockwise (Fig. 10) about the pin |9| under the biasing iniluence of the trigger 99. This rotatior disengages the end 95 of the trigger 99 imm the overhanging portion |9| of the latchi'fi' and permits the trigger to rotate counter-clceizwise about the pivot pin 99. One end of the toggle link 65 is carried above the Acenter line of the toggle, and the toggle then collapses toward the base 29 of the trip device thereby opening the breaker, the various parts of the mechanism movlng to the positions shown in. Fig. 10.

Similarly, in the event ci a short circuitl er a very heavy overload in the circuit controlled by any one of the poles, suicient magnetomotive force is supplied by the conducting strip |93 to cause the armature |3| to be attracted to the pole piece ||9. Byalterlng the size of the spring |33,` it is possible to calibrate the unit to operate to any reasonable degree of overload approaching the short circuit condition. The downward movement of the armature |9| toward the base is transmitted to the trip bar through the projecting stud |29, the latch being released in substantially the same manner as before.

It isdesirable to have a trip structure for a circuit breaker that is capable of opening the breaker after a predetermined time interval upon the occurrence of an overload in the controlled circuit, because in the normal operation of industrial feeder circuits, momentary moderate overloads are -oi frequent occurrence, and it is essential that the breaker does not open immedlately. in response to one of these moderate overloads. It is, however, equally important that the breaker open immediately upon the occurrence of a short circuit or a very heavy overload in order to protect the circuit equipment, 75

l accuse and it was with these requirements in view that the trip structure of my invention has been evolved. By proper adjustment oi' the springs |33 it is' possible to secure instantaneous operation upon the occurrence of heavy overload within reasonable limits, and it is always possible to secure instantaneous operation of the breaker upon the occurrence of an overload approximating a short circuit condition. 'Ihe thermally responsive elements introduce a time delay in the operation of the trip devices and are capable oi carrying moderate overloads for short periods of time without opening the interrupter.

Should an attempt be made to close the breaker against an overload or against a short circuit condition, the latch 91 will be released after a predetermined time delay or instantaneously, depending upon the magnitude oi overload exactly as described before. The trigger will likewise be released and will cause the toggle mechanism to break so as to open the breaker independently ot the position oi the operating handle.V Thus, it is not possible to hold the breaker closed against a short circuit or against a continued overload condition.

After the breaker has been opened by the trip device, it is necessary to restore the mechanism from the tripped position (Fig. 10) to the operative position (Fig. 8). The projection |81 on the operating handle 23 is provided for this purpose. Following the tripping oi the breaker, the handle 25 may vbe moved yclockwise (Fig. l0) whereupon the projection |81 which engages the end |89 oi the trigger I8 will cause the trigger to rotate clockwise about its pivot 8S.v As the operating handle 23 nears the limit of travel in a clockwise direction, the end of trigger 09 abuts against the overhanging portionA lli of the latch l-trigger 91 having been returned by! its biasing spring ISS to its normal position whe-re it is held by the projection til on the trip barand moves the entire latch 91 (Fig. 10) toward the base 28, the latch sliding in the slots |13. Finally, the projecting end 95 passes beneath the overhanging portion ISI and the latch snaps back to the normal position under the inuence of `its biasing spring |65. The lenti-re breaker mechanism is now in the open operative position (Fig. 8) and may be closed by a movement of the operating handle 23 exactly as described above.

While in accordance with the patent statutes, I have given the foregoing details of a practical embodiment of-my invention, it is to be understood that many of these are merely illustrative and that variations oi their precise form will be desired in some applications. I desire. therefore, that the language of the accompanying claims be accorded the broadest reasonable construction and that my invention be limited only by that which is explicitly stated in the claims and by the prior art.

I claim as my invention:

1. In a trip device `for a circuit interrupter, a conducting member, and a thermally responsive member, said conducting member having a portion of reduced section, a part of which portion extends along a part oi said thermally responsive member, a portion of saidthermally responsive element being thermally conductively joined-to said conducting member adjacent said reduced portion.

2. In a trip device for a circuitl interrupter, a bar oi' conducting material, anda member o! bimetallic thermally responsive material, said tion extending along a part of said thermally reconducting bar having a portion 4of reduced section, a part oi which portion is disposed closely adjacent to a part of said bimetallic member,

said `bimetallic member having a portion which is thermally conductively joined to said conduct- 5 ingvbar. i

3. In a trip device for a circuit ,interrupter, a bar of conducting material having a portion of reduced section, and a member of bimetallic thermally responsive material having tapering sides, one end of said bimetallic member being thermally conductively joined to saidconducting bar adjacent said reduced portion, apart of said reduced portion being disposed substantially parallel to a. part of said bimetallic member. l5

4. In a trip device for a circuit interrupter, a strip oi conducting material having a portion of reduced section, and a thermally responsive member of bimetallic material having tapering sides, the end oi.' the thermally responsive mem- 20 ber having the greatest width being thermally conductively joined to said strip of conducting material, a part of said portion o1' reduced secsponsive element. 25

5. In a trip device i'or a circuit interrupter, a lconducting member having a single retlexed bend therein, and a thermally responsive member oi' bimetallic material supported on said conducting member and having a portion thermally 30 conductively joined to a portion of said conducting member and aportion extending along a considerable portion oi' one side oi said reilexed bend.

6. In a trip device for a circuit interrupter, a conducting bar having a portion oi'reduced sec- 35 tion and a reilexed bend therein, and' a thermally responsive member of bimetallic material having tapering sides, the end oi' the thermally responsive member having the greatest width being supported on, and thermally conductively joined to, 4i) said bar oi conducting material, adjacent said portion of reduced section, a part of said thermally responsive member extendingy along and closely adjacent to a considerable portion of one side of said reilexed bend.

7. In a trip device for a circuit interrupter,

a substantially U shaped frame, a thermally responsive member extending through said frame,

an armature slidably supported by said frame, a core member positioned adjacent said armature, 50 and a trip bar disposed adjacent said frame, said bar being operable by either said thermally responsive member or by said armature.

8. In a trip device for a circuit interrupter, a frame member, a thermally responsive member ot 55 bimet'allic material mounted thereon, arry armature slidably supported thereby, a core member positioned adjacent said armature, and a trip bar disposed adjacent said frame, said bar being operable by either .said thermally responsive member 6.0

ture slidably supported thereby, a core member positioned adjacent said amature, and a pivotaliy u mounted trip bar disposed adjacent said frame, said bar being operable by either said thermally responsive member or by said armature.

11."Inv a' trip device for a circuit interrupter, asubstantially U shaped frame, a thermally responsive member of 'bimetallic material mounted thereon and extending through said U, an armature slidably supported thereby, a core memberl mounted upon said frame adjacent said armature, and a single conducting means having aportion looped into said U for heating said thermally responsive member, and a portion for energizing said core member.

' said base and for providing terminals for said- 12. In a removable trip device for circuit interrupters, a base, electro-responsive means mountedon said base, and an integral conducting strip, releasably connectible at each end, for supporting trip device, said conducting strip acting as an energizing means for said electro-responsive means during the operation of said device.

13. In a circuit interrupter, a switch member, means for biasing said switchl member to one position, means including a trigger member for releasably restraining said switch member in one position, and a trip device including a latch engaging one end oi said trigger and thereby releasably restraining said switch member in one position, said latch being slidably and pivotally mounted.

14. In a circuit interrupter, a. switch member, means for biasing said switch member to the open position, means including a pivoted trigger member for releasably restraining said switch member in the closed position, and a trip device including a reieasable latch for engaging one end of said trigger and thereby releasably restraining said switch member in the closed position, said latch being slidably andpivotally mounted, and rotating about its pivot point to release said trig- 15. In a circuit interruptor, a switch member, means iorbiasing said switch member to the open` position, means including a pivoted resettable trigger tor releasably restraining said switch member in the closed position. said trigger rotating in one direction when releasing said switch membery and rotating in the opposite direction when movingto the reset position, and a trip device including a reieasable latch for engglng one end oi.' said trigger and thereby releasably rcstraining said switch member in the closed position, said latch being slidably and pivotally mounted, said latch rotating about its pivot point to release said trigger and sliding along its mounting to reengage saidtrigger when said trigger moves to the reset position.

16. In a circuit interrupter, a base, an operating mechanism mounted on said base, and av removable trip device which is disposed within a suitable recess in said base, said trip device comprising a base member, at least one electro-responsive trip element mounted thereon, a means i'or operatively engaging said operating mechaand supporting means which includes the poles and each supported at one end thereof on ingmaterialpivotallysunpcrtedonsaldbale member and extending across two or more poles of said circuit interrupter,'said tripbar being moved from a normal inoperative position to a tripped position during each tripping Operation through the engagement therewith of one or more oi' said thermally responsive elements, means biasing said trip bar to said inoperative position, and individually adjustable engaging means intermediate each of said thermally responsive elements and said trip bar. g

18. In a trip device for a circuit interrupte havingv a plurality of poles, a plurality' oi bimetallic thermally responslveelements. each electrically connected in the circuit controlled by one of said poles, a plurality of magnetically responsive elements, each energized in response to the current iiowingin the circuit controlled by one oi said poles, and a movable trip bar extending across two or more poles oi said interrupter, each of said thermally responsive elements and each of said magnetically responsive elements including individual means for directly engaging said trip bar to cause said trip bar to move to the tripped position upon the occurrence of predetermined conditions, saidtrip bar in` cluding means i'or insulating the points on said bar which are engaged by said thermally responsive elements and by said magnetically reu sponsive elements from each other.

19. In a trip device for a circuit interruptor having a plurality oi poles, a'plurality of bimetallic thermally responsive elements, each electrically connected in the circuit controlled by one of said poles, a plurality oi' magnetically responsive elements, each energized in response to the current flowing in the circuit controlled by one oi said poles, and a movable trip bar extending across two or more poles o! said circuit interrupter for engagement by any one ci said plurality oi' thermally responsive elements, said plurality of magnetically responsive elements each including a movable armature mechanically connected to said trip bar at all times, said trip gaged by said thermally responsive elements andv the armature oi' said magnetically responsive elementaany one oif said plurality ot thermally responsive and said magnetically4 responsive elements being capable of causing said trip bar to move to the tripped position upon the occurrence x of predetermined conditions.

20. In a circuit interrupter; a base; contact means and actuating means for moving said contact means to open and to close the electrical circuit through said interrupter mounted on said base; and a removable trip device for cooperating -with said actuating means; said trip device including a separate base. at least one electro-responsive trip element mounted thereon,v means for operatively engaging said actuating mechanism, and supporting means i'or rigidly supporting the base oi' said trip device upon said main base and for accuratelyv positioning said trip base with respect to said main base; said supporting means including an integral conducting strip releasably connectible at each end into the electrical circuit through said interruptor; said conducting strip acting as an energizing means for said said contacts to open and to close the electrical circuit through said interrupter supported onsaid base; and a removable trip device which is normally disposed within' a suitable recess formed withinsaid` base; 'said -trip device including a secondary base member, at least one electro-respons'ive trip element mounted on said secondary base member, means for operatively engaging s aid operating mechanism, and an integral, conducting strip, releasably connectible at each end, for supporting said secondary base and for providing terminals for said trip device; said conducting strip acting as an energizing means for said electro-responsive means during the operation of said device, and being adapted to accurately position said device within said recess in said base member.

22. In a circuit interrupter; separable contact means; actuating means for moving said contact means to open and to close the electrical circuit through said interruptor; and a trip device for cooperating with said actuating means; said trip device being operable upon the 'occurrence of predetermined vconditions to `cause said actuating means to move said contact means to the open circuit position, and including a latch member which normally engages and holds said actuating means. said latch member being rotatable about a pivot point which is xed during its releasing movement, electro-responsive means for effecting the release of said latch member, and biasing means normally biasing said latch member to the latched position; said electro-responsive means being operable upon the occurrence of prede- 1 termined conditions to effect therelease of said latch member, and said actuating means, upon the release of said latch member, automatically moving said contact means to the open circuit position; said trip device being automatically resettable following each operation thereof, and said latch member which normally engages and holds said actuating means being movable independently of the other elements of said trip device in order to permit the reengaging of said actuating means following each automaticresetting operation. Y

23. In a circuit interrupter; separable contact means movable to an open circuit and to a closed circuit position: actuating means for said contact means including a member movable from a normal inoperative position to an operative position to cause said contact means to be moved from the closed circuit to the open circuit lposition, and means biasing said member to said operative position; and a trip device for cooperating with said actuating means; said trip device including alatch which normally restrains said member from moving to said operative position, means biasing said latch to the latched position, and electro-responsive means for eifecting the release of said latch upon the occurrence of predetermined conditions; said trip device being resettable following each operation thereof to the extent that said latch is automatically restored to the normal latched position immediately following the release /of said movable member; said actuating mechanism including means for causing said movable'member to reengage said latch means following each circuit opening operation produced by the operation of said trip device. and

said latch being movable independently of the other elements of said trip device inorder to permit the relatching of said movable member without disturbing the lnormal reset position of the other elements of said trip device.

, 24.- In a circuit interrupter; separable contact means movable to an open circuit and to a closed circuit position; actuating means for said contact means including a pivotally supported member movable from a normal inoperative position to an 5 operative position to cause said actuating means to move said contact means from the closed circuit to the open circuit position, -and means biasing said movable member to said operativeposition; and a trip device for cooperating with said actuating means; said trip device including 4 a pivotally supported latch which normally restrains said member from moving to said operative position, means biasing said latch to the latched position, a plurality of electro-responsive i5 elements each operable upon the occurrence of A i differing predetermined conditions to effect the release of said latch, a member intermediate said latch and said electro-responsive elements which is movable in response to the operation of any one of those elements to eifect the release of said latch, and means biasing said intermediate member against movement to effect the release of said latch; said trip device being automatically resettable following each operation thereof; said actuating means including means for causing said movable member to reengage said latch. following each circuit opening operation produced by the operation of said trip device, and said latch being movable independently of said intermediate member and said electro-responsive elements to permit the reengagement of said latch and said pivotally supported member movable to cause said actuating means to move said Contact means to the open circuit position without moving said intermediate member or said electro-responsive element-s from their normal reset position.

25. In a trip device for a circuit interrupter, a

' conducting member, and a thermallyI responsive member, said conducting member` having a portion of increased resistance, atleast a part of which portion extends along a part of said thermally responsive element, and a portion of said thermally responsive element beingy thermally conductively joined to said conducting member a adjacent said portion of increased resistance.

26. In a trip device for a circuit interrupter, a strip of conducting material having a portion of increased resistance, and a thermally responsive member of bimetamc material having tapering 5 sides, the end of the thermally responsive member having the greatest width being thermally conductively Joined to said strip of conducting material, and at least a part of said portion of 55 increased resistance 'extending along a part of said thermally responsive element.

27. In a trip device for a circuit interrupter, a relatively rigid member of conducting material having a single reilexed bendtherein, athermally eo responsive member of bimetallic material supported on said conducting member and having a portion thermally conductively Joined to said conducting member adjacent saidv portion of increased resistance and a portion extending along c5 a considerable portion oi' one side of said reexed bend.

28. In a trip device for a circuit interrupter; a frame member, a thermally responsive element vsupported on said frame, a core member also 7o tionv of increased resistance adjacent said thermally responsiveelement.l

29. In a trip device for a circuit interrupter,

a frame member, a thermally ve element..

comprising a flat strip o! bimetallic material having a length at least several times its width, supported at one of its ends on said frame, a core member also supported on said frame, and a ain-- gle conducting member for heating said bimeta1 lic thermally responsive element and tor ing said core, said conducting member including f a portion oi increased resistance normally disposed adjacent said thermally responsive element and a single reiiexed bend normally looped'about said core. Y

30. In a multi-pole circuit interrupter. a base. separable contact means for opening and for closing a plurality of poles mounted on said base. actuating means for said contact means, and a removable trip device operable upon the occurrence of predetermined conditions to causel said actuating means to move said contact meansing said trip base with respect to said main base.. said supporting means including a-plurality of' integral conducting strips each oi' which is releasably connectible at each end thereof into the electrical circuit through one ot the poles: o! said.

interrupter, each of said conducting strips being provided with a portion oi increased resistance. inorderthatit-shallserve asanenerging means for one o! said thermally responsive elements dur-.v

ing the operation of said trip device, and with portions which serve as terminals for said trip device.

3l. In a multi-pole circuit interrupter, a main' base, separable contact means for opening and for closing a plurality o! poles mounted on said ibase. actuating means for said contact-means.

anda removable trip device operable uponthe oi predetermined conditions to causo 10 actuating means to move said contact means from the closed circuit position to the open circuit position. said trip device including a separate base.' a plurality of thermally responsive tripping Y elements mounted thereon, a plurality of magnetically responsive tripping elements, each oi which includes a core member and movable armature. likewise mounted on said separate base. a single trip bar supported on said separate base soastoextendacrossapluralityofthepolesoin said interrupter, said trip bar being movable from a normal inoperative to an operative position to eilect the operation of said trip device in response tothe actuation of any one of said thermally responsive or said magnetically responsive tripping elements. and supporting means for rigidly supporting the base o! said4 trip device upon .said main base and tor accurately positioning thesaid trip base with respecttosaidmainbase. saidsupporting means including a plurality of integral ao conducting strips releasably connectiblle at each end thereof into the electrical circuit through one of the poles of said interrupter. each ot said conducting strips having a portion oi' increased resistance for energizing one of said thermally as responsive elements and a portion adapted to inductively link with one o! said core members for energizing one of said magnetically responsive elements. said conducting strips being also provided with portions which serve as terminals for a said trip device.

HARRY J. LINGAL,

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