US973924A - Circuit-breaker. - Google Patents

Description

a sunt-ps sum L ATTORNEY Patented oct. 25, 1910.

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APPLIOATIOX FILED JULY 13, 1001.

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J. c. Dow. CIRCUIT BREAKEB.

.APPLIULTIDR FILED JULY 13. 1007.

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UNTTED STATE-s PATENT Ormes. y

JAIES C. DOW, OF WIIV'JKINSBURG, PENNSYLVANIA, ASSIGNOR '1"0V WESTINGHOUSE ELECTRIC MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CIRCUIT-BREAKER.

y Bpecincatien o! Letters Patent. Application filed July 13, 1907. Serial No. 383,659.

Patented Get. 25, 1910.v

To all whom it may concern;

Be it known that I, JAMES C. Dow, a citizen of the United States, anda resident of Wilkinsbur in the county of Allegheny and State o Pennsylvania, have invented a new and useful Im rovement in Circuit- Breakers, of which the following is a specication.

My invention relates -to automatic circuit interrupters, and it has for its object to rovide a device of this class that sha] be simple in construction and that shall einbody an improved release mechanism.

In the prior art, circuit-breakers have usually com rised release mechanisms in which movab e core members were attracted, under predetermined conditions, by station'- ary core members for the pur ose of tripping latches or other holding evices. flfhe weight of the movable core member was sometimes relied, upon to oppose, to a greater or less degree, the attraction of the energized stationary core member, but springs have been more generall empl0yed,`by reason of the facility with w ich their tension may be adjusted. The principal diiculty, in a construction of this character, arises from the fact that the increased ast preaches the stationary member and, consepull exerted by the spring is quently, the tripping action is rendered n n-k certain and the attractive energy necessary to effect an interruption of the circuit is `not clearly defined.

According -to my present invention, IV e ploy an improved release mechanism which avoids the diiculties of the prior'afrt by so arranging the movable parts that when a. predetermined attractive force is exerted by the stationary core member a well defined action of the movable parts is eiectcl and, consequently, an accurate adjustmen may .be made.

Figure 1 of the accompanying drawings is a side elevation of. a circuit interrupter constructed in ,accordance with my invention. Figs. 2, 3, 4, 5 and 6 lare detail -views l 'of the operating and release mechanisms of the device shown iii Fig. 1,'and, Fig. 7 is a view, similar to Fi .1, of a circuit-breaker having a modified form of vtripping mechanism.

Referring to Figs. 1 to 6, inclusive, in which a preferred construction is shown,

e movable core memberrapthe device here illustrated comprises stationary contact members 1 and 2 which are mounted on a stationary slab or switchboard panel 3 of insulating material, a movable bridging contact member 4 and an operatingmechanism 5.

The interrupter is equipped, in the usual manner, v with arcing contact members 7 and 8 which effect a final break of the circuit when the interrupter opens. The movable contact member 4 comprises a laminated part 6, the beveled ends of which engage the stationary members 1 and 2 when the interrupter is closed, and a holder 9.k The holder 9 is rotatably supported upon a shaft. 10 by means of a link 11. The operating mechanism 5, of which the link 11 forms a part, is supported by side plates 12 that project from the insulating slab 3 and 'cornprises a handle lever 16 and an operatin bell-crank lever 13, the latter being fu crumed upon a stationary shaft 14 and con'- nected, at one end, to the holder 9 by means of a link 15. v Y

The movablearcing contact member 8 is supported at one end of an arm 17 that is fulcrumedupon ashaft 18 with which the holder 9 is provided and is held inengage" ment with the stationary arcing contact member 7, when the interrupter is closed, by means of a spring 20 which connects the free end of the arm 17 with a pin'projec'tion 21 on the bell crank lever 13. .A

The release mechanism comprises a. ini/1gnet winding 22 which is intrposedelectrically b`etween the stationary contact iii'eniber 2 and one termina-l 23 of the circuitfinterrupter, a stationarycore member 24, a movable core .member or armature 25,3. latch lever 26 and a. tension spring 27. ,'The armature 25 is movably mounted about a shaft. 2 8 which is located considerably below and slightly at one side of its center of gravity, and the arrangement of parts is Such that the weight of the armature and the force of attractionl exerted by the' stationary core member 24 are'unitedin lopposition to the spring 27. Movement ofv the armature'25 .K is limited in one direction bythe stationary coremember and may be limited in theopposite direction by any suitably located stop device. y

As illustrated in Figs. '5 and 6 of the drawings, the armature 25 is in the form of 'circuit.

a two-part lever comprising side strips 29, the center lines of which are substantially .verticah hub `membersl30 and a laminated of the side strips 29 is provided with 4a forked projection 32 to which the upper end of the spring 27 is attached. The tension of the spring'27 may be adjusted by a thumbscrew 35 and a nut 33.

.The latch 26, which is inthe form of a bell-crank lever, is mounted upon the shaft 28, between the hub` members of the armature 25, and is resiliently connected to the armature by means of a spring 36. The arm 37 of the latch lever 26 is bifurcated and is provided with a roller 38 that may be engaged by a hook projection 39 which extends laterally from one arm of the operating bell crank lever 13 and has a beveled inner end. vThe rotary movement of the latch lever 26 is limited by a cross-bar 40 of the` amature 25. A

As the circuit interrupter is closed, the latch lever is raised in opposition to the spring 36 by the engagement of the roller 38 with the beveled surface of the hook projection 39. A ointer 41 projects from the nut 33 and is a a ted to indicate, in connection with a suitabllj* graduated plate 42, the current value at which a predetermined tension of the spring 27 may be overcome.

The handle lever 16 is provided with an' insulating handle 43 and is illustrated in dctail in Figs. 2 and 3. It is fulcrumed upon the shaft 14 and its movement in one direction effects a rotary movement of the operating lever in thc same direction by reason of the engagement of the handle lever .with a lateral projection 44 with which the operatinglever 13 is provided.

lhe operation of the device is as follows: .l\ssumi1rg that the interrupter occupies its closed position, as indicated inthe drawings; the release mechanism may be operated in two ways tovsuddenly effect the disengagement of the contact members and the interruption of the circuit. This result may be accomplished manually by raisin the handle 43 and its handle lever 16 until the extremity of the arm 45 engages the upper end of the latch lever 26 and rocks it u on, its shaft 28 sufficient-ly to release thero ler 3S from the hook projection 39. As soon as the holding mechanism .is thus released, the spring 20, which is under tension when the interruptor is closed, causesl immediate separat-ion of the stationary and movable contact members and the interruption of the A similairesult may be effected automatically if the current traversing the winding 22 exceeds a predetermined amount since the stationary core member 24, being thus energized, will e'ec-t a'rotative movement of the armature 25 in opposition to the spring 27 and its movement will, in turn, effect a movement of the latch lever 26. Reference may now be had to Fig.' 7, in whichl corresponding parts are indicated by the same reference characters. The stationary and movable contact members are substantiallyY the same as those represented' in Fig. 1, but the movable core member or armature of the release mechanism is arranged with its center of gravity below its center of rotative ,movement The latch mechanism and the operating levers are adapted to the aforesaid arrangement of the armature. The lower extremity of the operating lever 13 is provided with a roller 4G and the latch mechanism comprises projections 47, 48 and 49, the first named. of .which is adapted to engage the roller 46.

. The movement of the armature 50 produces movement of the latch mechanism by coming into contact With the' projection 49 and a similar movement may be effected manually by the engagement of arm 45 on the handle lever 16 with the projection 48. The movement of the latch is limited in one direction by a stop' 51 and its movement in the opposite direction is opposed byl a spring 52 which; is connected, at one end, to the projection 47' and atl its other end to the stationary stop rejection 51. l

, It will be observed that, in both forms of 4 circuit interrupter illustrated, the sprin 27 100 is so arranged relative to the center o rotative movement of the armature that, as these parts operate, the spring is put under tension, but, at the same time, the point of application of the force soexerted is continually moved more nearly into a line which passes through the center of rotative movement'and the stationary terminal ot'l the spring. Consequently, although the spring exerts a greater force, its turning 11o moment.is not increasedI in the same proporl f tion and may be decreased, if desired. By this means, a quick and decisive action of the tripping mechanism is effected as soonas the attraction of the stationary core mem- 1,15 ber is suflicient to cause an initial movement of the armature. This result may more readily obtained by the structure shown in Fig. 1, by reason of the fact that the center of gravity of the armature moves to a 120 greater distance from a vertical line through its center of rotative movement and the moment of the force due to gravitation, which tends to actuate t-he'armature in opposition to the sprintf, is increased. lnthis Way, the 125 influence ofD the spring is lessened as the forces which'opposeit are increased.

It will be understood that structural modifications may be effected Within the scope of .my invention, and I desire, there- 13G fore, that only such limittions shall be imposed as are indicated in the. appended claim.

I claim as my invention:

'In a circufit breaker, the combination with nn insulating base plete, stationary and movable contact members, .an interposed link, a bell crank operating lever having an inwardly extending hooked projection, and :1. bell crank latch pivotally supported between the operating lever and the bese and :idnpted to cooperate with the hooked projection of the operating lever in holding the breaker closed, of u release magnet havlng a.

movable core member pivotally mounted coaxially with the latch and resiliently connected thereto, and a handle lever supported coaxielly with the operating lever and havw ing lprojection adapted either to close the c JAMES c. DOW.E

lVitnesses:

R. J. DEARBORN, BIRNEY HINES.

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