US708710A - Circuit-breaker. - Google Patents

Description

' No. 703,7m. Patented sept. 9, |902.

E. M. HEWLETT.

CIRCUIT BBEAKER.

(Application med sept. 29, 189s.)

(No Modell.)

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v Edward ffewlett.

No. 7na,7|o. v Patented sept. 9, |902.

E. M.. HEWLETT.

CIRCUIT BREAKER. (Application Bled Sept. 29, 1898.) (No ModeL) 2 Sheets-Sheet 2.

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' Ltg- TH: Nbnms PETERS co. PHoToLlTHo., wnsumo. oy c UNITED STATES PATENT OFFICE.

EDVARD M. HEIVLETT, OF SCI-IENEOTADY, NEI/V YORK, ASSIGNOR,

BY MESNE ASSIGNMENTS, TO II. WARD LEONARD, OF BRONX- VILLE, NEW YORK.

CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent No. 708,710, dated September 9, 1902. Application led September 29,1.898l Serial No. 692,160. (No model.)

To @ZZ whom. t may concern:

Beit known that I, EDWARD M. HEWLETT, a citizen of the United States, residing at Schenectady, county of Schenectady, and State of New York,have invented certain new and useul Improvements in Circuit-Breakers, (Case No. 869,) of which the following is a speciiication. Y

My present invention relates to automatic circuit-breakers for electric machinery, and more particularly to those ofthe double-pole type. Its embodiment consists, in its essential features, of two independent switches which are operated, preferably simultaneously, by a tripping-coil. Each side of the I circuit is provided with one of the switches,

which may be of any convenient form, and the tripping-coil which operates the two may be in either side of the circuit or, if desired, may be divided and part of the coil put upon each side. This, however, is not the preferred form on account of the additional complication of circuits and increased cost ofthe apparatus. Myapparatus thus serves both as a double or single pole switch or as an automatic circuit-breaker. It obviously possesses great advantages over the ordinary double-pole switch, in' which the two blades are connected mechanically, so that they are opened simultaneously and closed in a similar manner. It oftens happens in closing the circuit after a circuit-breaker has blown that the short circuit or overload condition has not been removed. Under such circumstances the closing ofthe circuit by hand may produce serious accident either to the apparatus or to the operator, inasmuch as the handle, being the grasp ot' the operator, would retard the opening of the circuit so much as to cause arcing, and in the case of, for instance, a dead short circuit on a large machine might, perhaps, wreck the machine or even the station. Such accidents have in the past been caused in this manner. With the apparatus of my invention, however, such an accident would be impossible, because in its operation one side of the circuit is lirst completed by closing one of the switches, which in itself sets the circuit-breaker ready for operation. The operator then closes the other switch, and if the short circuit or overload is still maintained the switch which was rst closed is immediately thrown open and all damage prevented. Ordinarily the arrangement ot' apparatus will be such that the two sides of the circuit will be opened simultaneously. This is of course the best arrangement, as it not only kills7 all of the parts of the circuit at once, but provides a number of breaks in series, so that the interruption of large currents is facilitated.

In the construction ofthe device I have arranged the handle so that when the circuit opens the handle is thrown up and projects in a substantially horizontal position. This arrangement I prefer-,because it enables me to put the circuitbreaker higher up on the switchboard and prevents the arc being close to the attendents. It also keeps the arc away from the instruments upon the switchboard. This is a convenient arrangement, because by the connecting mechanism between the contact and the handle the motion of the handle is at iirst quite easy, and as the contact is made it moves harder. Thus in reaching for the handle when only the lingers of the hand touch it itis nevertheless readily moved, and at the time when any strength must be exerted to close the contacts firmly it is in such a position that it may be grasped firmly bythe whole hand. The particular combination by which this is effected I do not, however, claim in this case, but reserve it for another application.

Under the bridging-contact, which is now almost universally employed in circuit-breakers, I arrange a barrier of insulating material between the two stationary contacts spanned by the bridge, and I make a part of this barrier movable and force it outward by a spring, so that it follows the bridge when the circuit is broken by the opening of the switch. The adjustment ot' this spring is such that it assists in overcoming the friction of the sliding contacts which are in shunt to the bridge.

IVhile I have illustrated in the accompanying drawings a suitable and convenient embodiment of my invention, the particular apparatus used is immaterial so long as the IOO main feature of the independent switches, (two or more,) with a trip arrangement designed to open them all as occasion demands, be employed.

The drawings annexed show, in Figure l, a front elevation of the circuit-breaker ready to mount upon the switchboard; in Fig. 2, a side elevation of the parts shown in Fig. l. Fig. 3 is a diagram of the circuits, and Fig. 4 is a detail.

Describing first Figs. l and 2, A is the base, made of any suitable insulating material noncombustible in character. For this purpose slate or porcelain may be used, as is customary. B B are the handles of the two switches. These are counterparts, so that a description of one will answer for both. Cisa trippinghandle, by which the switches may be opened mechanically. D is the series coil acting on overload in the well-known way. To t-he handle C is afxed 'a rod C3, connected to the armature E of the series coil. C' is a spring, and C2 an adjusting-screw, by means of which the capacity of the circuit-breaker may be adjusted as required to open upon different amounts of current flow. The handle B is pivoted at b in a projection from the frame of the device, and a link B2 connects it with a bell-crank lever B3. Connected to the outer end of the bell-crank lever are conductingbars B4, separated from the lever B3 by insulation b4. Upon each end of the conductingbars is a spring-contact B7, making rubbing contact with carbon blocks G2, which form the shunt-terminals of the device. The bars B4 may or may not betlexible if the contacts BT have sufcient flexibility; but preferably they are yielding. A bridge B6 is carried by the bell-crank B3 and is in electrical connection with the bars B4. This spans the main terminals G G', whose contact-faces are in the same or approximately the same vertical plane, and is composed of a number of strips of copper, phosphor-bronze,or other goed conducting material. lt is of well-known formthat is, the ends of the laminze make a yielding and rubbing contact with the terminal blocks. A spring B8 is attached to the inner end of the handle B. To maintain the toggle composed of the handle and the link B2 in its illustrated position, (see Fig. 2,) another toggle composed of the links b2 b3 is einployed. As will be seen, when the circuitbreaker is set this toggle is cramped above a line drawn between its ends. It is provided (see Fig. l) with a lug b5, projecting from one ot' its members. Aftixed to the armature E of the series coil is a yoke composed of the two bars F F, cooperating with the lugs b5 b5 when the circuit-breaker is tripped. The spring b acts to throw the toggle positively to a position above the center. Under each of the bridges is a barrier composed of two sheets or blocks I I, ot' insulating material, secured to the base of the apparatus. Be-

tween the two is another block l', which is thrust outward by the spring I2, surrounding the pin 12,'whenever the switch is opened. The spring l2 also aids the spring Bsin opening the switch. A detail of the construction is shown in Fig. 4, which shows the piece I in plan. As will be seen, it is provided with shoulders vlfi, which engage with the pins t' z'. Suitable barriers K K, Fig. l, of insulating material, separate the two sides of the circuit. X, in Fig. 2, shows a bolt which serves at once for electrical connection from apparatus external to the switch with the massive contact-block G and to secure said contact-block G mechanically to the switchboard or base A. The terminal blocks are tapped to receive the bolts, and such blocks are drawn forcibly against the switchboard or base by means of nuts on the rear of the base or switchboard.

The circuit of the apparatus' is shown in Fig. 3, where M is the generator, motor, or other apparatus or circuit to be protected, the rest of the parts being easily recognizable.

The operation of the device as thus described is as follows: When the current increases to or above a maximum predetermined bythe adjustment of the spring C', the armature E is attracted, the bars F strike the lugs b5 b5, and throw down the toggle b2 b3. The spring B8 then pulls the inner end of the handle down and the toggle formed of the handle and the link B2 collapses, drawing with it the bell-crank B2. The bridge BG is first withdrawn from the main terminals, thus shuntin g the current through the carbon-terminals G2 G2 and the spring-terminals B7, this break occurring an instant after the bridge has left the main terminals. The insulating-piece I follows the bridge in its removal until stopped by the pinst'. A cushion bl, of rubber or other elastic material, receives the shortarm of the bell-crank lever B3.

As already brieiiy described in the statement of invention, it will be seen that the handle B moves upward when the toggle b2 b2 is thrown to the other side of the center by the bar F, the spring BS readily overcoming the smaller spring b, and thus the handle assumes a substantially horizontal position, with the advantages already pointed out.

It is manifest that if one of the arms F should be of different length from the other the switch controlled by that arm would be tripped before or after the other one, and such IOO IIO

a variation would clearly be within my ining skill. I do not illustrate or describe such arrangements, as they are quite obvious to those skilled in the art.

Vhat I claim as new, and desire to secure by Letters Patent of the United States, is-

l. In an electric switch, the combination of a pair of fixed contacts, a bridging-contact and a barrier of insulating material between the fixed contacts and spanned by the bridge;

the barrier consisting of fixed and movable portions, and means for causing the movable part to follow the bridge as the switch is opened.

2. In a switch, the combination of a spring for opening the switch, a toggle for closing it, and a second toggle holding the first one extended.

3. In a switch, the combination of fixed and movable contacts, a toggle connected to the movable contacts, and a second toggle for holding the iirst in its extended position.

4. In a switch, the combination of fixed and movable contacts, a toggle connected to the movable contacts, a second toggle for holding the first in its extended position, and a spring for cramping the second toggle positively out of line.

An automatic circuit-breaker provided with a switch, a toggle for closing the switch, a second toggle for holding the first one extended, and an armature and series coil for causing the second toggle to release the switch.

o'. The combination of a plurality of electric switches each comprising terminal blocks, a laminated member for bridging said blocks, independent means for bringing the laminated member into engagement with the terminal blocks, and a single controlling device for automatically controlling the movement of said switches.

7. The combination of a plurality of electric switches each comprising separated terminal blocks, a laminated bridging member for engaging'said blocks, a toggle for operating each laminated bridging member, independent means in each switch for operating said toggle, and a single controlling device for automaticallyY controlling the movement of said switches.

8. The combination of a plurality ot'- electric switches, each comprising separated terminal blocks, a laminated bridging member for engaging said terminal blocks, a pivoted arm supporting said laminated bridging niember at approximately its middle, independent means in each switch for operating said pivoted arms, and a single controlling device for automatically controlling the movement of said switches.

9. The combination of a plurality of electric switches, each comprising separated terminal blocks, a pivoted laminated bridging member for engaging said terminal blocks, independent means in each switch for operating the pivoted laminated bridging member, and a single controlling device forantomatically controlling the movement of said switches.

10. The combination of aplurality of electric switches, each comprising separated terminal blocks, a pivoted laminated bridging member for engaging said blocks, a toggle for operating said pivoted laminated member, and independent means in each switch for operating the toggle, and a single controlling device for automatically controlling the Inovement of said switches.

ll. The combination of a plurality of electric switches juxtaposed, and in series in the saine electric circuit, each switch comprising separated terminalblocls, a laminated bridging member for engaging said 'terminal blocks to close the circuit, independent means in each switch for operating said bridging member, and a single electric responsive device for automatically controlling the movement of said switches.

l2. The combination of a plurality ot electric switches capable ot independent manual movement into normal position, each switch comprising separated terminal blocks, a laminated bridging member for engaging said blocks, meansrfor locking said bridging member in engagement with said terminal blocks, and a single electroresponsive device for automatically unlocking all the switches.

13. The combination of a plurality of electric switches designed to be moved independently into normal position, each switch comprising separated terminal blocks, a pivoted laminated bridging member for engaging said terminal blocks, independent locking devices for holding said switches in their normal posit-ion, and a single electroresponsive device for automatically releasing said switches.

14. The combination of a plurality of electric switches capable of independent movement into normal position, each switch comprising separated terminal blocks, one vertically above the other, a laminated bridging member for engaging said blocks, independent means in each switch for operating said bridging member, and a single controlling device for automatically controlling the movement of said switches.

15. The combination of a plurality of electric switches capable of independent Inovement into normal position, each switch comprising separated terminal blocks whose contact-facesareinapproximatelythesameplane, a laminated bridging member for engaging said terminal blocks, independent means in each switch for operating said bridging inember, and a single controlling device for automatically controlling the movement of said switches.

16. The combination of a plurality of electric switches, capable of independent movement into normal position, each switch comprising separated terminal blocks, one vertically ahove the other, and whose contactsurfaces are in approximately the same vertical plane a laminated bridging member for ICO IIO

engaging said terminals, independent means in each switch for operating the laminated member,and a single electroresponsive device for automatically controlling or effecting the simultaneous movement of said switches.

17. The combination of a plurality of switches, independently movable into normal position, each switch comprising separated terminal blocks, a laminated bridging member for engaging said terminal blocks, a stationary shunt-contact located upon and above the upper terminal block, a movable shuntcontact cooperating with said fixed shuntcontact, locking devices for holding said switches in their normal positions and a single electroresponsive device for automatically and simultaneously releasing said switches.

18. The combination of a plurality of electric switches independently movable into normal position, each switch comprising separated terminal blocks, a laminated bridging member normally engaging with said terminal blocks, locking means for holding said bridge in engagement with said terminal blocks and a single electroresponsive device for automatically and simultaneously releasing the bridging devices of the switches from the control of their locking devices.

19. The combination of a plurality of electric switches independently movable into normal position and juxtaposed upon a common base, each switch comprising separated terminal blocks, one vertically above the other, a laminated bridging member cooperating with said terminal blocks, independent means in each switch for operating the laminated member, and a single electroresponsive device located between a pair of said switches for automatically and simultaneously releasing all the switches.

20. The combination of a plurality of electric switches independently movable into normal position, each switch comprising separated contact terminals, a laminated bridging member for engaging said contact terminals, independent means in each switch for operating the laminated member, a single electroresponsive device for automatically and simultaneously releasing said switches,and barriers of insulating material located between the independent switches.

2l. An electric switch comprising separated contact-blocks one vertically above the other, and whose engaging faces are in approximately the same vertical plane, a laminated bridging member engaging with the ends of the laminze upon said contact-blocks, means for bringing said bridging member into engagement with said blocks, means for locking said bridging member in engagement with said blocks and electroresponsive means for controlling the switch.

22. In an electric switch the combination of separated contact-blocks one vertically above the other and whose contact-surfaces are in approximately the same vertical plane, astationary shunt-contact, a movable laminated electroresponsive means for controlling the switch.

23. In an electric switch the combination of separated contact-blocks one vertically above the other, and whose engaging faces are in approximately the same vertical plane, a shunt-contact in electrical communication with the upper contact block and located above the engaging surface thereof, a laminated bridging member, for engaging with the ends of its laminas with the engaging surfaces of said contact-blocks, a vertically-extending pivoted member, a movable shunt- Contact carried at the upper end thereof, means for restraining the laminated bridging member in normal position, and electroresponsive means for controlling the switch.

24. In an electric switch the combination of separated contact-blocks one vertically above the other, and whose engaging faces are in approximately the same vertical plane, a shuntcontact in electrical communication with the upper contact-block and located above the engaging surface thereof, a laminated bridging member, for engaging at the ends of its laminae with the engaging surfaces of said contact-blocks, a vertically extending pivoted member, a movable shunt-contact carried at the upper end thereof, and means for restraining the laminated bridging member in normal position.

25. In an electric switch,the combination of separated contact-blocks one vertically above the other, and whose engaging faces are in approximately the same vertical plane, a shuntcontact in electrical communication with the upper contact-block and located above the engaging surface thereof, a pivoted laminated bridging member for engaging at the ends of its laminze with the engaging surfaces of said contact-blocks, a vertically extending pivoted member a movable shunt carried at the upper end thereof, and means for restraining the laminated bridging member in normal position.

2G. In an electric switch the combination of separated terminal blocks, one vertically above the other and having their engaging faces in approximately the same vertical plane, a horizontally spring-pressed member located between such terminal blocks, a laminated bridging member for engaging with said terminal blocks and in its normal position compressing said spring-pressed member, means for restraining said laminated member in its normal position, and means for releasing the switch.

27. In an electric switch the combination of separated contact-blocks one vertically above the other, and having their engaging facesin approximately the same vertical plane, a stationary shunt-contact in electrical communi- ICO III)

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cation with the upper contact-block and located above the engaging face thereof, a laminated bridging member for engaging said terminal blocks, a spring-pressed member located between said terminal blocks and exerting pressure against said laminated member in its normal position, a vertically-extending pivoted member, a movable shunt-contact carried at the upper end thereof, and means for restraining the laminated bridging member in normal position.

2S. In an electric switch the combination of separated contact-blocks one vertically above the other, and having their engaging faces in approximately the same vertical plane', a stationary shunt-contact in electrical communication with the upper contact-block and located above the engaging face thereof, a laminated bridging` member for engaging' said terminal blocks pivoted on an axis parallel with the base, a spring-pressed member located between said terminal blocks, and exerting pressure against said laminated member in its normal position, a vertically-extending pivoted member, a movable shunt-contact carried at the upper end thereof and means for restraining the laminated bridging member in normal position.

29. In an electric switch the combi nation of separated contact-blocks one vertically above the other, and having their engaging faces in approximately the same Vertical plane, a stationary shunt-contact in electrical communication with the upper contact-block and lo cated above the engaging face thereof, a laminated bridging member for engaging said terminal block, spring means located between said terminal blocks and exerting pressure against said laminated member in its normal position, a vertically-extending pivoted member, a movable shunt-contact carried at the upper end thereof, and means for restraining the laminated bridging member in normal position.

30. In an electric switch the combination ofl separated contact-blocks one vertically above the other, and having their engaging faces in approximately the same vertical plane, a stationary shunt-contact in electrical communication with the upper contact-block and located above the engaging face thereof, a laminated bridging member for engaging said terminal blocks pivoted on an axis parallel with the base, and spring means located between said terminal blocks and exerting pressure against said laminated member in its normal position,a vertically-extending pivoted member, a movable shunt-contact carried at the upper end thereof, and means for restraining the laminated bridging member in normal position.

3l. In an electric switch the combination of a base of insulating material, separated contact-blocks secured thereto by means of bolts extending through said base and serving also as an electrical connection to said blocks, one of said blocks located vertically above the other, said blocks having their engaging surfaces in approximately the same vertical plane, a laminated bridging member for engaging with said contactblocks, resilient means located between said blocks and exerting presssure against said bridging member in its normal position, means for forcing said bridging member into engagement with the contact-blocks and means for restraining said bridging member in its normal position.

32. In an electric switch the combination of separated contact-blocks, one vertically above the other and having their contact-faces approxim ately in the same Vertical plane, a laminated bridging member for engaging said contact-blocks, a lever pivoted on an axis parallel with the base and carrying at its upper end said laminated contact member, a toggle controlling said pivoted lever, and means for locking the toggle in its extended position.

In an electric switch the combination of separated contact-blocks, one vertically above the other, a laminated bridging member for engaging said contact-blocks, aleverpivoted on an axis parallel with the base and carrying at its upper end said laminated contact member, a toggle controlling said pivoted lever, and a second toggle for locking said toggle in its extended position.

In witness whereof I have hereunto set my hand this 27th day of September, 1898.

EDWARD M. HEWLETT. Witnesses:

B. B. HULL, M. H. EMERSON.

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