US2487637A - Multipole circuit breaker and tripping device therefor - Google Patents

Description

New. 8, 1949 T. M. COLE ET AL.

MULTIPOLE CIRCUIT BREAKER AND TRIPPING DEVICE THEREFOR 1O Sheets-Sheet 1 Filed Aug. 8, 1944 ATTORNEY.

Nav. 8, 1949 T. M. CQLE ET AL iZfl-flifig MULTIPOLE CIRCUIT BREAKER AND TRIPFING DEVICE THEREFOR Filed Aug. 8, 1944 10 Sheets-Sheet 2 ZNVENTOR5 Nov. 8, 1949 T. M. QGLE ET AL zmmw MULTIPOLE CIRCUIT BREAKER AND Nov. 8, 1949 "r. M. COLE ETAL 2,487,637

MULTIPOLE CIRCUIT BREAKER AND TRIPPING DEVICE THEREFOR ATTORNEY.

Nov. 8, 1949 T. M. COLE ET AL MULTIPOLE CIRCUIT BREAKER AND TRIPPING DEVICE THEREFOR 1O Sheets-Sheet 5 Filed Aug. 8, 1944 4 Z 2 E Z M w w m w 2 6 \ll I? 2 [1| 2% w Z H 4 i, w u 2 HHMWH i m T l! w w.

I w. M A. E m n N m K N I H/M Q m 4 w M m 0 w 7 6 0 0 6 T iii e "My? F J I Y M 4 0 4 m 1 I 2 Z 0 0 m a 6 %5 w; 5

Nov. 8, 1949 T. M. COLE ET AL MULTIPOLE CIRCUIT BREAKER AND TRIPPING DEVICE THEREFOR l0 Sheets-Sheet '7 Filed Aug. 8, 1944 BY 62AM Nov. 8, 1949 T. M. COLE ET AL 2,487,637

- MULTIPOLE CIRCUIT BREAKER AND TRIPPING DEVICE THEREFOR 10 Sheets-Sheet 8 Filed Aug. 8, 1944 90 i Q i INVENTOR5 THoMns M (04 AND WILL/AM HAHNT'L Nov. 8, 1949 T. M. COLE ETAL 2,487,537

MULTIPQLE CIRCUIT BREAKER AND TRIPPING DEVICE THEREFOR l0 Sheets-Sheet 10 Filed Aug. 8, 1944 INVENTOR5 THOMAS COLE Am; WILLIAM H i T2 a-now ATTORNEY- Patented Nov. 8, 1949 MULTIPOLE CIRCUIT BREAKER AND TRIPPING DEVICE THEREFOR Thomas M. Cole, New York, N. Y., and William H. Lantz, Jr., East Orange, N. J., assignors to Federal Electric Products Company, Newark,

Application August 8, 1944, Serial No. 548,550 18 Claims. (Cl. 200-116) This invention relates to multi-pole circuit breakers and to tripping devices therefor. More particularly, the invention is concerned with a multi-pole circuit breaker which can be manually opened and closed and which is also opened automatically at all of the poles upon the occurrence of an overload in the circuit at any one of the poles.

In general, the circuit breaker is of the type disclosed in the application for Letters Patent of the United States, Serial No. 467,842, now Patent No. 2,421,830, June 10, 1947, filed December 4, 1942, by Louis W. Cole and Thomas M. Cole, and the tripping device of the present application is also, in general, of the type disclosed in said application.

The present invention will be fully understood from the following description considered in connection with the accompanying drawings illustrating the presently preferred embodiment of the invention.

In the drawings:

Fig. 1 is a perspective view of a circuit breaker embodying the present invention;

Fig. 2 is a fragmentary perspective view of the circuit breaker at the load side thereof;

Fig. 3 is a top plan view of a circuit breaker, with the casing cover removed;

Fig. 4 is a sectional view on the line 4-4 of Fig. 3, the breaker being closed;

Fig. 5 is a sectional View on the line 5-5 of Fig. 3, but with the casing cover in place, the circuit breaker being tripped;

Fig. 6 is a sectional view on the line 8-6 of Fig. 3, but with the casing cover in place, showinfi the circuit breaker in the manually opened condition thereof and showing part of the tripping device in its said condition;

Fig. 7 is a bottom or rear plan view of the casing of the circuit breaker;

Fig. 8 is a sectional view on the line 8-8 of Fi 1;

Fig. 9 is a view on the line 9-9 of Fig. 8;

Fig. 10 is a sectional view on the line iO-lfl of Fig. 3;

Fig. 11 is a sectional view on the line ll-H of Fig. 10;

Fig. 12 is a perspective view of one of the spring projectedholding members of the tripping device;

Fig. 13 is a perspective view of a lever device forming part of the means for resetting the tripping device following the tripping of the circuit breaker;

Fig. 14 is a perspective view of one of the members for holding the lever device illustrated in Fig. 13 on a companion pivot;

Fig. 15 is a perspective view of parts of the tripping device illustrated in separated but related positions with portions omitted for illustrative purposes;

Fig. 16 is a sectional view on the line lS-IB of Fig. 3, parts being omitted for the purpose of illustration; r

Fig. 17 is a perspective view of the trip released means which also constitutes means for mechanically connecting certain of the contact members of the circuit breaker for conjoint operation;

Fig. 18 is a sectional view on the line l8|8 of Fig. 17;

Fig. 19 is a perspective view of certain of the parts illustrated in Fig. 17, .said parts being shown in separated but related positions;

Fig. 20 is a sectional view on the line 2020 of Fig. 16, parts being omitted for the purpose of illustration.

Referring to the drawings in detail, the hereinafter described tripping device and the operating parts of the switching unit of the circuit breaker are enclosed within a casing it provided with a cover 52, said casing and its cover being preferably molded from any suitable plastic, for example, Bakelite. A separately formed mounting unit M (Fig. 15), also molded or otherwise iormed from a suitable plastic, is set into the casing at one end thereof as shown in Fig. l. and is secured in position by screws l8 (Fig. '7) which extend through openings 20 in the bottom 22 of the casing and engage and thereby fasten the line terminal connecting members 24 in posi tion. The terminal connecting members 24 are thus secured in mechanical and electrical engagement with companion terminal members 26, 28 and 30. Said terminal members 26, 28 and 30 are secured to the base 32 of mounting member 14 by hollow pins 34 which have their opposite ends flanged or peened over the companion terminal member and the bottom of base 2 of the mounting member as indicated at 36 and 38, respectively, (Figs. 15 and 16). The openings 40 in hollow pins 34 register with the openings 20 through which the screws 18 are entered for securing the terminal connecting members 24 in position. The mounting member I4 is provided with integral upstanding posts 42 which form barriers between the several terminal connecting members 24 and the adjacent portions of the terminals 26, 28 and 30. Said terminals will be subsequently more specifically described in explaining the construction of the tripping device. The terminal connecting members 44 for the load side of the circuit breaker .are shown in Fig. 2, said terminal connecting members being fastened to the companion terminal members 45 by screws 48 which are entered through openings 50 in the bottom of the casing (Figs. 6 and 7). Barriers 52 integral with the casing l0 separatethe terminals 46 and the load terminal connecting members 44 from each other. Openings 54 are provided adjacent the four corners of the casing 10 for bolts 56 for removably fastening the cover I2 to the casing. Two of said openings 54 are for bolts by which the unit is fastened to a support, the holes for two other fastening bolts for securing the unit to a support being indicated at 51.

The switching unit of the circuit breaker comprises a one-piece manually operable member 58 molded or otherwise formed from insulation material, for example, Bakelite." Said member is positioned in the casing I8 and extending transversely thereof between the opposite sides 68 of the casing. Manually operable member 58 has an arcuate segmental portion 62 from which an integral finger grip 64 extends for access externally of the casing through a slot 66 provided in the arcuate portion 68 of the cover I2. As illustrated in Fig. 6, the inner surface of the arcuate cover portion 68 lies adjacent, with slight clearance, to the segmental arcuate portion 62 of the manually operable member 58. Manually operable member 58 is mounted for pivotal movement in casing I8 by means of pivot pins 18 and 12 which are fixed in the axially aligned end openings 14 and 16, respectively, by the milled or roughened in-portions 11 and 18. The circular heads 88 and 82 of pins 18 and 12 constitute trunnions and are received in bearing openings in bearing plates 84 which are mounted in vertical grooves 86 in the adjacent side walls 68 of the casing, said grooves being open at the top or front of the casing. Retaining plates 84 are held in position by the lower edges 81 of the side flanges 88 of the cover.

The manually operable member 58 has axially or laterally spaced integral web portions 98, 92, and 94. Contacts 96, one for each pole of the breaker or switch, are secured to said web portions, respectively. Contact members 98, I88 and I82, each in the form of a lever, are pivoted, respectively, on the end pins 18 and 12 and upon an intermediate pin I84 which is formed of insulation. The insulation pin I 84 has a sliding fit in the intermediate openings I86 which are in axial alignment with the end openings 14 and 18. Pin 12 extends through an opening I88 and abuts the end of pin I84, the opposite end of which is abutted by the end of pin 18. It will be understood that pin I84 and contact member I02 which is pivoted on said pin are assembled with the manually operable member 58 before one of the end pins 18 or 12 and the companion contact member pivotally mounted thereon are mounted on said manually operable member. As pins 18 and 12 are preferably formed of steel or other metal, the insulation pin I84 insulates said first mentioned pins from each other. It will be noted that the end pins 18 and 12 are provided with circular bearing portions I I8 and H2, respectively, between theshank and head portions of the respective pins to provide bearings for the contact members 98 and I88. Movement of -contact members 98 and I88 axially of their pivots is prevented by the bosses H4 and H6 on the web portions 98 and 94, respectively, and by the adjacent surfaces of the bearing plates 84, while movement of the contact member I82 axially of its pivot pin I 84 can not occur because said contact member fits, with a slight clearance,

-in the space between the web 92 and web II8.

Webs I I8 and I 28 provide barriers between the contact members at the several poles of the breaker and are provided with ribs I22 which fit with clearance in companion arcuate grooves I24, respectively, in the upper edges of upstanding projections I26 on the bottom or back wall- .bers 98,

of easing I8. The contact members 98, I88 and I82 are biased for movement away from their respective companion contacts 96 by two springs, each of which has a coiled portion I28 (Figs. 4, 5 and 8) and end portions I30 and I32 which bear against the edge I34 of the arcuate portion 62 and against one arm of the companion lever contact members 98 and I88, respectively, the spring engaged lever arms of said contact members 98 and I88 being indicated at I38 and I38, respectively, said springs acting on member I82 through the cross member I42 hereinafter described.

Contact members 98, I88 and I82 are mechanically connected for joint operation by a rigid cross member I42 (Figs, 3 to 6 and .17). Cross member I42 also constitutes a trip released member, as will subsequently more fully appear in the explanation of the tripping device. In order to compensate for any inequalities in the engagement of the contact members 98, I88 and I82 with their companion contacts 96, respectively, which are fixed to the manually operable member 58, provision is made for allowing a limited movement between the cross member and the lever arms I36, I38 and I48 of said contact mem- I 88 and I 82, respectively. The means provided for this purpose is illustrated more clearly in Figs. 17 to 19, and by reference thereto,

it will be noted that the cross member I42 is provided with a plurality of spaced openings I44 into which the laterally oifset ends I46, I48 and I 58 of the contact member lever arms I36, I38 and I48, respectively, project. Figs. 18 and 19 illustrate the connection in respect to the offset end I46 of the arm I36 of the contact member 98, but it will be understood that each of the oifset ends of the arms of the contact members are connected to the cross member I42 in the same manner. Thus, as illustrated, the end portion I46 of arm I36 is provided with a small arcuate opening or slot I52 through'which a pivot pin I54 projects, said pivot pin passing through a pair of aligned openings I56 in a bracket I58, the opposite end portions I68 of said pivot pin being bent around the companion bracket as illustrated in Fig. 1'7. Each bracket I58 projects into a companion opening I44 in the cross member I42 and is held in position by a U-shaped clip I62 which engages the cross member I42 at the opposite sides thereof. More particularly, each U-shaped clip I 62 is provided with a pair of aligned openings I64 in which the companion bracket I58 fits, each of said brackets having a pair of outturned ends I66 which bear against the adjacent side I68 of the companion clip I62, it being understood that the outturned ends I66 of each bracket I58 are formed after the bracket is inserted through the companion openings I64 of the companion clip I62. Each clip is provided with a pair of inwardly directed struck-out tongues I18 which engage the cross member I 42 at the bottom of the opening I44 for securing the clip to said cross member. A spring I12 is positioned in each opening I44 and bears against the end I46, I48, or I58 of the companion contact member as illustrated in Fig. 18, for resiliently opposing movement between connecting member I42 and contact members 98, I88 and I82. It will be understood that cross member'I42 is formed of insulation material so that the contact members are insulated from each other.

In the normal condition of the circuit breaker, cross member I42 is held against movement in a clockwise direction (viewing Fig. 4) beyond a enema-r predetermined point by the spring projected members I14 of the tripping device which will hereinafter be more particularly described. When the cross member I42 is thus held against movement in a clockwise direction beyond the spring projected members I14, the circuit breaker can be manually opened and closed by pivotal movement of the manually operable member 58 in counterclockwise and clockwise directions, respectively, (viewing Fig. 4), the closed condition of the circuit breaker being illustrated in Fig. 4, and the manually opened condition of the circuit breaker being illustrated in Fig. 6. Provision is made for engaging and disengaging the contact members 88, I88 and I82 with their companion contacts 98, respectively, with a snap action, in the manual operation of the circuit breaker. For this purpose, the springs I18 are provided. Each of said springs has an intermediate coiled position I18 andend portions I88 and I82. As shown in the drawings, there are two springs I18, the ends I88 of which engage in companion recesses I84, respectively, in the inner ends of the-laterally spaced inwardly molded projections I88 (see Figs. 6 and 7). The other ends I82 of the two springs I18 engage the manually operable member 58 in notches I88 in the web portions 98 and 94 respectively (Figs. 4 and 6).

The tripping device for automatically opening the circuit breaker at all of the poles thereof upon the occurrence of an overload or predetermined current now at any one of the poles of the circuit breaker will now be described. As explained above, when the clrcuit'breaker is manually closed, the cross member I42 engages the spring projected members I14 which in the projected positions thereof are in the path of movement of said cross member whereby the movement of the latter in a clockwise direction, viewing Fig. 4, beyond a predetermined point, is limited by the engagement of said cross member with said spring projected members. The latter are mounted for sliding movement in grooves I98 formed in the inwardly extending ledges I92 (Fig. 10) of the inwardly moldedportions I94 of the casing. A spring I98 is positioned in each of said grooves for projecting the companion member I14 and for opposing movement of the latter to its retracted positionf Plates I98 of insulation material are secured to ledges I92 over spring projected'members I14 by screws I99 or in any other suitable way and form, with the walls of the companion grooves I98, guideways for the spring projected members I14. Each of the spring projected -members I14 is provided with an integral laterally extending arm 288 which is movable in a recess 282 (Fig. 11) in ledge I92 to allow movement of arm 288 when the spring projected member I14 which carries said arm moves in the companion groove I98 of said ledge.

spring projected holding members I14 are moved to their retracted positions against the force of springs I95 by and under the control of a trip releasing member 284, which is shown in perspective in Fig. 15. Said trip releasing member 284 is formed of insulation material and is mounted for movement on a plurality of rods 288, there being as here shown three of said rods disposed in triangular relation. said rods are fixed at their outer thread ends to the terminal members 28, 28 and 38, respectively. More particularly, as illustrated in Fig. 16, the central terminal member 28 has a portion 288 to which a companion rod 288 is secured. As illustrated in Fig. 15 the terminal member 28 has an upwardly directed portion 2I8 provided with a threaded opening for the securement thereto of another oi said rods 288, while as illustrated in Fig. 16, the terminal member 28 has a similar upwardly extending portion 2I2 for the securement thereto of the third rod 288. Nuts 2I8 are provided on rods 288 for locking said rods to the companion terminal members. The relation of parts 288, 2I8- and 2I2 of the terminal members 28, 38 and 28, respectively, is illustrated more clearly in Fig. 28.

The trip releasing member is provided with recesses 2I4 into which the rods 288 project, each of said recesses having an opening 2I8 surrounding the companion rod 288, said opening being somewhat larger in diameter than the rod so that the trip releasing member 284 not only can move longitudinally of said rods 288, but can also tilt thereon. A spring 2I8 is disposed in each recess 2I4 and bears at one end thereof against the inner end of said recess and at the opposite end thereof against the head 228 provided on rods 288, as illustrated in Fig. 16. Thus trip releasing member 285 is spring retracted and is movable to a projected position against the force of the spring 2I8 in the recesses 2. A plurality of triangularly arranged retaining members 222, preferably formed of metal are securely fixed in trip releasing member 284, preferably in the molding of said trip releasing member. In the projected position of trip releasing member 284, said retaining members 222 are engaged adjacent their outer ends by triangularly arranged current responsive members 224 each of which consists of a bimetallic or thermostatic strip. The inner end of each bimetallic strip 224 is secured to the terminal member at the companion pole, and more particularly to the vertical part 288, 2I8 or 2I2 of the companion terminal, as illustrated in Fig. 16 with reference to the securement of the bimetallic strip 224 to the vertical portion 288 of the terminal member 28. For this purpose, the bimetallic strip 224 has a bent end portion 228 which is welded to the part 288, H8 or 2I2 of the corresponding terminal member. In order to provide for the adjustment of the thermostatic strips 224 in relation to the ends of the companion retaining members 222 of the trip releasing member, the parts 288, 2I8 and 2I2 of the terminal members are provided with bent end portions 228, 238 and 232, respectively, each extending longitudinally of the companion thermostatic strip 224, as illustrated more clearly in Fig. 16. These end portions of the terminal members are each provided with an adjusting screw 233 in threaded engagement therewith and bearing on the companion thermostatic strip for adjusting the latter in relation to the companion retaining member 222 in a way obvious from the illustration. Each thermostatic strip 224 is electrically connected by a pig tail or other flexible conductor 234 to one of the contact members 98, I88 and I82. The stationary contacts 98 are connected to the companion terminals 48 at the load side of the breaker by similar flexible conductors or pig tails 236.

From the above description, it will be understood that upon the occurrence of an overload or other predetermined current flow at one or more poles, the corresponding bimetallic strip 224 through which the current passes will flex out of engagement with the companion retaining member-222 of the trip releasing member 284 whereby the latter will be moved to its retracted position by the springs 2| 8. As the arms 20!! of the spring projected holding members I16 are in the path of retractive movement of said trip releasing member 2%, said arms are engaged by said trip releasing member during the movement of the latter to its retracted position and thereby the spring projected holding members 5143 are moved to their retracted positions to release the cross member 662 whereby to eifect the tripping or the breaker. More particularly, when the spring projected holding members I16 are retracted, thereby releasing the cross member M2, the springs which engage or act upon the contact members 98, I do and I 02 move the latter clockwise, viewing Fig. 5. out of engagement with the companion contact members 98, respectively, until the forward arms of said first mentioned contact members engage the fiange 238 at the forward edge of the arcuate part 62 of the manually operable member 58, and thereafter said contact members 98, Hill, :02 continue to move pivotally in the same direction together with the manual operating member until the finger piece 55 thereof engages the edge 2% of the cover I2 at the slot 55. The opposite edge 242 of said slot is engaged by finger piece 66 of the manually operable member when the circuit breaker is manually opened, which is accomplished by moving said manually operable member in a counterclockwise direction, viewing Fig. 4, following the resetting of the breaker.

As indicated above,-provision is made for resetting the breaker following the tripping thereof so that said breaker can be manually closed. For

this purpose, the manually operable member 58 is providedwith a cam 244 which cooperates with a cam operated lever device 245. As illustrated in Fig. 5, the cam 246 is formed as an integral part of the web 92 of said manually operable member so. The cam operated lever device 266, which is illustrated in perspective in Fig. 13, comprises the laterally spaced lever arms 268 and 250 which are bent toward each other at their forward ends and welded in abutting face-to-face relation, as illustrated in Fig. 13, said forward ends 252 and 254 being appropriately contoured at their peripheral edges for operative engagement by the edge of cam 246% as illustrated in Fig. 5. Lever arms 248 and 250 of the cam lever device 246 are provided with arcuate bearing recesses 256 and 258 which engage arcuate bearing members 260 formed as molded projections on the bottom of casing I2 interiorly thereof,

whereby said cam operated lever device 266 is mounted for pivotal movement in the casing. The arms 248 and 250 are held in pivotal engagement with the companion bearings 260 of the casing by the retaining members 262 one of which is shown in perspective in Fig. 14. Each of said retaining members comprises a downwardly extending arm 264 having a lower arcuate edge 266 which engages an arcuate edge portion 268 of the companion arm of thelever device 246 (Figs. 4 and 5). Also, the retaining member 282 comprises a cross bar 210, a transverse dove-tail projection 212, and upstanding projections 214 and 216. The bars 210 of the two retaining members 262 are supported on the'ledges 21B of the casing (Figs. and 11), with the transverse projections 212 fitting in correspondingly shaped dove-tail recesses 280 formed in the casing portions I94 adjacent said ledges 218, respectively. The transverse end portions 282 and 284 of bar 210 of the retaining member 262 are positioned in correspondingly shaped recesses 29B and 2-98, respectively, while the upstanding portions 214 and 216 are positioned in vertical grooves 299 and 292,

respectively, extending upwardly from the ledges 218 to the top of the ledges 592. The upper ends of parts 216 and 21d of the retaining members 252 are engaged by the plates 598 which overlie the spring projected holding members H16. Thus, the retaining members 252 are held in fixed position in the casing and byengaging the arcuate portions 268 of the arms of the cam operated lever device 246 hold said arms in pivotal engagement on their companion bearings 260. Longitudinally extending ribs 296 molded on the bottom of the casing interiorly thereof, and the adjacent longitudinally extending wall portions 296 of said casing provide grooves in which the lever arms 248 and 250 movably fit whereby said lever arms are held against movement toward or away" from each other.

The lever arms 248 and 25D have vertical upstanding parallel portions 2% and B, inwardly inclined portions 302 and 3M and forwardly inclined horizontal end portions 386 and 308 which are positioned to engage the'trip releasing member 204 (Figs. 4, 5 and 10) for moving the latter, against the force of springs 2E8, to its projected or set position in which the ends of the bimetallic strips 226 engage the retaining members 222 of said releasing member 204, when said bimetallic strips flex inwardly upon cooling thereof following the tripping of the circuit breaker. The breaker resetting operation takes place by moving the manually operable member 58 in a counterclockwise direction, viewing Fig. 5, whereby the lever device 2 86 is pivotally moved also in a counter-clockwise direction .by the engagement of the edge of the cam 2 84 with the peripheral edge of the cam follower portion constituted by the ends 252 and 252 of the lever arms 268 and 250. It will be understood that the cam 244i and said cam follower of the cam operated lever device M6 are contoured so that the cross member M2 of the switch unit moves upwardly beyond the spring projected holding members i1 1 before the tri releasing member 204 is moved sufiiciently to release said spring projected members #14 for movement to their projected positions. In this connection it will be understood that when the manually operable member is moved counterclockwise for resetting the circuit breaker, the contact members 98, I00 and I02 are engaged by the flange 238 and are thus pivotally moved in a counter-clockwise direction to position the cross member I 62 connected to said contact members upwardly or forwardly of the casing beyond the spring projected members I 14. Thereafter the manually operable member is moved in a clockwise direction whereupon the cross member I42 engages the spring projected members I14, thus holding the contact members 98, I00 and I02 stationary without, however, preventing the completion of the movement of the manually operable member in said clockwise di-= rection, which does not take place until the contacts 96 engage the companion contact members 98, I06 and I02, said contact engagement for closing the breaker occurring with a snap action as a result of the overcentering springs I16.

While we have shown and described the pre-v ferred embodiment of our invention, it will be understood that the latter may be embodied otherwise than as herein specifically illustrated or described and that in the presentIy preferred 7:; embodiment herein shown or described certain changes in the details of construction and in the arrangement of parts may be made without departing from the underlying principles of the invention within the scope of the appended claims.

Certain matter not claimed herein is claimed in our divisional application Ser. No. 109,868, filed August 12, 1949.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A tripping device for a multi-pole circuit breaker which has a plurality of movable contact members, one for each pole, and a member connecting said contact members for conjoint movement from circuit-closed position to circuitopened position, spring-projected means releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a trip-releasing member movable from a set position to a. retracted position and engageable, during said movement thereof, with said spring-projected means for releasing the latter from said connecting member, and current responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrence of a predetermined current flow at any one of the poles of the circuit breaker to release said trip-releasing member for movement to said retracted position thereof.

2. A tripping device for a multi-pole circuit breaker which has a plurality of movable contact members, one for each pole, and a member connecting said contact members for conjoint movement from circuit-closed position to circuitopened position, spring-projected means releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a trip-releasing member movable from a set position to a retracted position and engageable, during said movement thereof, with said spring-projected means for releasing the latter from said connecting member, current responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrenceof a predetermined current flow at any one of the poles of the circuit breaker to release said trip-releasing member for movement to said retracted position thereof, means for moving said connecting member to a re-setting position following the release thereof by said holding means, and means operable in response to the operation of said moving means for restoring the set positions of said trip-releasing member and said spring-projected holding means.

3. A tripping device for a multi-pole circuit breaker which has a plurality of movable contact members, one for each pole, and a member connecting said contact members for conjoint movement from circuit-closed position to circuitopened position, spring-projected means releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a trip-releasing member movable from a set position to a retracted position and engageable, during said movement thereof, with said spring-projected means for releasing the latter from said connecting member, current responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrence of a predetermined current flow at any one of the poles of the circuit breaker to release said trip-releasing member for movement to said retracted position thereof, means for moving said connecting member to a re-setting position following the release thereof by said holding means, and means operable in response to the operation of said moving means for moving said trip-releasing member from said retracted position to said set position thereof, said holding means being automatically spring-projected into holding relation with said connecting member upon said last mentioned movement of said trip-releasing member.

4. A tripping device for a multi-pole circuit breaker, comprising spring-projected means for holding the circuit breaker closed and movable to a breaker-releasing position, a trip-releasing member mounted for movement from asset position to a retracted position, three current-responsive members, one for each pole of the circuit breaker releasably engageable individually with said trip-releasing member at triangularly spaced points whereby said trip-releasing member is movable from said set position to said retracted position thereof whenreleased by any one of said current-responsive members, and means in the path of said trip-releasing member and movable thereby in the movement thereof to its retracted position for moving said holding means to the retracted position thereof to release the circuit breaker.

5. A tripping device for a multi-pole circuit breaker, comprising a trip-releasing member mounted for movement from a set position to a retracted position, a plurality of current-responsive members, one for each pole, individually releasably engageable with said trip-releasing member at triangularly spaced points for holding said trip-releasing member releasably in said set position thereof, said trip-releasing member being movable to said retracted position upon disengagement of any one of said current-responsive members therefrom, spring-projected means for holding the circuit breaker closed and movable to a retracted position to release th circuit breaker to open, and means associated with said holding mean-s and operable under the control of said trip-releasing member in the movement of the latter to said retracted position for moving said holding means to said retracted position to release the circuit breaker.

6. A tripping device for a multi-pole circuit breaker, comprising spring-projected means for holding the circuit breaker closed and movable to a breaker-releasing position, a trip-releasing member mounted for movement from a set position to a retracted position, three current-responsive members, one for each pole of the circuit breaker releasably engageable individually with said trip-releasing member at triangularly spaced points whereby said trip-releasing member is movable from said set position to said retracted position thereof when released by any one of said current-responsive member-s, and means in the path of said trip-releasing member and movable thereby in the movement thereof to its retracted position for moving said holding means to the retracted position thereof to release the circuit breaker, and manually operated means for moving said trip-releasing member from said retracted position to said set position thereof, said holding means being automatically spring-projected into holding relation with said circuit breaker upon said last mentioned movement of said trip-releasing member.

7. A tripping device for a multi-pole circuit breaker, comprising a trip-releasing member 1i mounted for movement from a set position to a retracted position, a plurality of current-responsive members, one for each pole, individually releasably engageable with said trip-releasing member at triangularly spaced pointsfor holding said trip-releasing'member releasably in said set position thereof, said trip-releasing member being movable to said retracted position upon disengagement of any one of said current-responsive members therefor-m, spring-projected means for holding the circuit breaker closed and movable to a retracted position to release the circuit breaker to open, means associated with said holding means and operable under the control of said trip-releasing member in the movement of the latter to said retracted position for moving said holding means to said retracted position to release the circuit breaker, and manually operated means for moving said trip-releasing member from said retracted position to said set position thereof, said holding means being automatically spring-pro- Jected into holding relation with said circuit breaker upon said last mentioned movement of said trip-releasing member.

8. A tripping device for a multi-pole circuit breaker which has a plurality of movable contact members, one for each pole, and a member connecting said contact members for conjoint movement from circuit-closed position to circuitopened position, spring-projected means releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a trip-releasing member movable from a set position to a retracted position and engageable, during said movement thereof, with said spring-projected means for releasing the latter from said connecting member, current responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrence of a predetermined current flow at any one of the poles of th circuit breaker to release said trip-releasing member for movement to said retracted position thereof, means for moving said connecting member to a re-setting position following the release thereof by said holding means, and means operable in response to the operation of said moving means for restoring the set positions of said trip-releasing member and said spring-projected holding means, said restoring means comprising a cam operable in response to said moving means and a lever pivoted between its ends and operable by said cam to impart said restoring movement of said trip-releasing member, said holding means being automatically spring-projected into holding relation with said circuit breaker upon saidlast mentioned movement of said trip-releasing member.

9. In a tripping device for a multi-pole circuit breaker, a trip-releasing member having retaining parts in fixed relation thereto at triangularly arranged points, current-responsive members releasably engageable with said retaining parts, respectively, for holding said trip-releasing member in set position, means mounting saidtrip-releasing member for movement from the set position thereof to a retracted position, said trip-releasing member having a plurality of recesses and said mounting means projecting into said recesses through openings which allow the releasing member to move relative to said mounting means and springs positioned in said recesses for moving said trip-releasing member to said retracted posi- I aeeaesr tion when released by said current-responsive members.

10. In a multi-poie circuit breaker having a plurality of movable contact members, means mechanically connecting said contact members for conjoint operation, and spring-projected means for releasably limiting the movement of said connecting means in one direction; springretracted means for moving said spring-projected means to retracted position to release said connecting means for movement independently of said spring-projected means, current-responsive members, one for each pole of the circuit breaker, pressing on said spring-retracted means at triangularly arranged points for releasably holding the same in projected position in opposition to the retracting force exerted thereon, said springretracted means being movable to it retracted position when any one of said current-responsive members releases the same, and means for moving said spring-retracted means to said projected position thereof comprising a resetting lever engageable with said spring-retracted means and operable by a movable part of the circuit breaker in the closing operation thereof.

11. In a multi-pole circuit breaker having a plurality of pivotall movable contact members, each of said contact members being mounted for pivotal movement on its own pivot, and means mechanically connecting said contact members of said connecting means, spring-retracted'means for moving said spring-projected means to re tracted position to release said connecting means for movement independently of said spring-proinjected means, and current-responsive means for releasably holding said spring-retracted means in projected Position. v

12. In a multi-pole circuit breaker having a plurality of pivotally movable contact members. one for each pole, each of said contact members being mounted for pivotal movement on its own pivot, a member connecting said contact members for conjoint movement from circuit-closed position to circuit-opened position, said connecting member being pivotally movable with said contact members about a common axis; rectilinealiy movable spring-projected means movable into and out of the path of said connecting member and releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a trip-releasing member movable from a set position to a retracted position and engageable, during said movement thereof, with said spring-projected means for releasing the latter from said connecting member, and current responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrence of a predetermined current flow at any one of the poles of the circuit breaker to release said trip-releasing member for movement to said retracted position thereof.

13. In a multi-pole circuit breaker having a plurality of pivotally movable contact members, one for each pole, eachof said contact members being mounted for pivotal movement on its own pivot, a member connecting said contact members for conioint movement from circuit-closed position to circuit-opened position, said connecting member being pivotally movable with said contact members about a common axis; rectilineally movable spring-projected means movable into and out of the path of said connecting member and releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a

trip-releasing member provided with means mounting said trip-releasing member for movement from a set position to a retracted position, said trip-releasing member being engageable, during said movement thereof, with said springprojected means for releasing the latter from said connecting member, current responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrence of a predetermined current flow at any one of the poles of the circuit breaker to release said trip-releasing member for movement to said retracted position thereof, said trip-releasing member having a plurality of recesses and said mounting means projecting into said recesses through openings which allow the releasing member to move relative to said mounting means, and springs positioned in said recesses for moving said trip-releasing member to said retracted position when released by said current-responsive members.

14. A tripping device for a multi-pole "circuit breaker which has a plurality of movable contact members, one for each pole, and a member connecting said contact members for conjoint movement from circuit-closed position to a circuitopened position, spring-projected means releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a trip-releasing member movable from a set position to a retracted position and engageable, during said movement thereof, with said spring-projected means for releasing the latter from said connecting member, and thermal responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrence of a predetermined current flow at any one of the poles ofthe circuit breaker to release said trip-releasing member for movement to said retracted position thereof.

15. A tripping device for a multi-pole circuit breaker which hasa plurality of movable contact members, one for each pole, and a member connecting said contact members for conjoint movement from circuit-closed position to circuitopened position, spring-projected means releasably engageable with said connecting member for holding the latter releasably in a set position whereby to hold said contact members in said circuit-closed position, a trip-releasing member movable from a set position to a retracted position and engageable, during said movement thereof, with said spring-projected means for releasing the latter from said connecting member, thermal load responsive means releasably holding said trip-releasing member in said set position and operable upon the occurrence of a predetermined current flow at any one of the poles of the circuit breaker to release said trip-releasing member for movement to said retracted position thereof, means for moving said connecting mem- "ber to a re-setting position following the release thereof by said holding means, and means operable in response to the operation oi said moving means for restoring the set positions of said trip- 14 releasing member and said spring-projected holding means.

16. A tripping device for a multi-pole circuit breaker, comprising spring-projected means for holding the circuit breaker closed and movable to a breaker-releasing position, a trip-releasing member mounted for movement from a set position to a retracted position, three thermal-responsive members, one for each pole of the circuit breaker releasably engageable individually with said trip-releasing member at triangularly spaced points whereby said trip-releasing member is movable from said set position to said retracted position thereof when released by any one of said thermal-responsive members, and means in the path of said trip-releasing member and movable thereby in the movement thereof to its retracted position for moving said holding means to the retracted position thereof to release the circuit breaker.

1'7. A tripping device for a multi-pole circuit breaker, comprising a trip-releasing member mounted for movement from a set position to a retracted position, a plurality of thermal load responsive members, one for each pole, individually releasably engageable with said trip-releasing member at triangularly spaced points for holding said trip-releasing member releasably in said set position thereof, said trip-releasing member being movable to said retracted position upon disengagement of any one of said thermal loadresponsive members therefrom, spring-projected means for holding the circuit breaker closed and movable to a retracted position to release the circuit breaker to open, and means associated with said holding means and operable under the control of said trip-releasing member in the movement of the latter to said retracted position for moving said holding means to said retracted position to release the circuit breaker.

18. In a tripping device for a multi-pole circuit breaker, a trip-releasing member having retaining parts in fixed relation thereto at triangularly arranged points, thermostat members releasably engageable with said retaining parts, respectively, for holding said trip-releasing member in set position, means mounting said trip-releasing member for movement from the set position thereof to a retracted position, said trip-releasing member having a plurality of recesses and said mounting means projecting into said recesses through openings which allow the releasing member to move relative to said mounting means, and springs positioned in said recesses for moving said trip-releasing member to said retracted position when released by said thermostat members:

THOMAS M. COLE. WIIlJAM H. LANTZ, .12.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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