US942491A - Electric switch. - Google Patents

Description

W. L. R. EMMET & E. M. HEWLETT.

ELECTRIC SWITCH.

APYLIOATION FILED FEB.14, 1901.

Patented Dec. 7, 1909.

Wlam L.R.Bmmet, Edward M Hewlett l Atm UNITED STATES PATENT OFFICE.

WILLIAM L. R. EMMET AND EDWARD IVI. HEWLETT, OF SCHENECTADY, NEW YORK,

ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SWITCH.

Specification of Letters Patent.

Patented Dec. 7, 1909.

Application led February 14, 1901. Serial No. 437,223.'

To all whom it may concern:

Be it known that we, WILLIAM Ln R. EM- nn'r and EDWARD M. HEwLn'rr, citizens of the United States, residing at Schenectady, count-y of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

This invention relates to switches or circuit breakers for electric currents, the object vbeing to permit the circuit to be made and broken effectively, without danger from fire or the holding over of the arc at the point of contact rupture.

,A further object is to permit the switch to automatically open upon an occurrence of overload in the circuit in which it is iiicluded and to prevent resetting of the switch while the overload continues.

In carrying out the invention, we surround the point of contact rupture by an insulating liquid such as oil and provide for the movement of the movable contact downwardly in the oil, the stationary contacts be= ing mounted so that soot which results from the carbonization of the oil by the arc formed on rupture will not deposit and interfere with the successful operation of the inachine. This feature is not claimed herein, but is covered by our Patent No. 789,597, dated May 9, 1905, and the novel features of the present application relate more particularly to means whereby the circuit can be broken automatically and by which it is rendered impossible for an operator to close the circuit and forcibly hold it closed under overload conditions in the circuit.

In the accompanying drawings, which illustrate the invention, Figure 1 is a sectional view of a switch embodying` our improveineiits, showing part of the switchboard on which the apparatus is mounted; Fig. 2 is a sectional view on a plane at right angles to that shown in Fig. 1; and Fig. 3 l

is a detail view of the escutcheon-plate which supports the` overload magnets, showing also the construction of the latter.

, 1 represent-s an oil tank or receptacle for L@ sliding in grooves formed in the sidewalls of the tank. The lower corners of the partitions are cut off, as indicated at 3 in Fig. 2, to permit circulation of the insulating liquid through several compartments. The partitions rise preferably above the oil level as indicated in Eig. 1, and thus not only separate the tank into several independent compartments, but act as insulating barriers to prevent an arc striking from one pair of contacts to another.

The switch shown in the drawings is adapted for tripliase alternating currents, though itwill of course be understood that the improvements are not limited to any particular kind of currents, being applicable generally to currents of all kinds, nor are many of the improvements limited to any particular type of switch or circuit-breaker. The tank is provided with a cast-metal cover 4;, bolted fast to the tank by means of ears provided on the cover and the tank respectively, as indicated in the drawings; and this cover has integral webs or walls forming bearings for the controlling and operating parts of the switch. In the cover are seated a number of insulating bushings 5, 6, i', 6 etc., one pair being allotted to each compartment of' the tank. These bushings are seated in the cover and fastened by a lead joint, as indicated at 8. Through each bushing passes a metal stein 9, 9a, the upper end of which is screw threaded to effect connection with a line connection or terminal- 10, and jam nuts as 11, 12, 11"L 12, are provided to lock the stem fast to the bushing and to the terminal 10. The lower end of the stem 9 is formed as a contact terminal comprising a thick bodyof metal bored with two transverse holes, as indicated at 13, 13a in F ig. 1, and the lower wall is split to permit the insertion of a bundle of laminated phosphor-bronze brush-contacts 14, 14%;92As will be evident from the drawings, we provide a pair of these contact terminals for cach cell of the oil tank, located below the surface of the oil and which may be bridged insulating fluid, which may be formed of galvanized sheet iron having overlappmg Jointsriveted and soldered so as to form a l Huid-tight vessel. other good insulator, and divided into a plurality of compartments by partitions 2,

It is lined with wood or l by a reciprocating movable contact member or switch element, such as a brass-yoke or bridge piece 15, provided with a tapering edge at the top to wedge into engagement withtlie yielding brush contacts of the contact terminals, as indicated at 15a on the eX- treme right of Fig. 1, in which the plane of the section has been slightly altered to show the construction of the engaging contact surfaces. These bridging contacts are carried by a stem of insulating material such as wood, as represented at 16, of which there is one for each bridge piece. In the switch shown in the drawing, for triphase currents, there are three of these insulating rods, one end of each being screwed to the center ot' one of the bridge pieces and the other ends being fastened into a metal cross-head loosely journaled in the end of a bell-crank lever 17 by a slot and pin connection in which the slot is elongated to permit a` slight lateral play. The other end of the bell crank lever is pivoted to a link 18 forming, together with an arm i9 of another bell-crank lever 20, a toggle which forms a power multiplying system for operating the movable contact member of the switch and is a desirable adjunct ot' the mechanism although not essential in all uses ot' the invention.. The other arm' of the bell-crank lever 20is connected to a bar 2l sliding in an actuator, such as a manually operable switch closing means or operating lever 22, the latter being forked to accommodate it; on the end of the bar 2l is a stop 2ld to engage the edges ot the fork. This actuator' or lever 22 carries a roller 23 cooperating with a restraining latch or detent 2a, mounted on an escutcheon plate 25 secured to the front of the base or switchboard 25a and spring controlled, as'

indicated, so that when the handle on the manual actuator or operating lever 22 is grasped by the operator and, is thrown in toward the board, the hook on the latch will pass over the roller and hold the actuator and connected parts in circuit closing position. Thus the switch may be closed and locked in a closed position. It is however, desirable to prevent closure of the circuit in case an overload or short circuit exists 'on the line, and we prevent this by means of a releasing device which automatically disconnects the contact member from the actuator in response to definite electrical conditions on the circuit and usually acts before the switch handle attains the fully closed position shown in Fig. l, where the restraining latch retains the actuator and connected parts in circuit closing position. By means of this device we disconnect the actuator or operating lever from the bar 21 and permit the movable element ofthe switch to fall back to its open position in response to its normal bias.

The actuator and the movable element of the switch are disenagageably connected by means of a latch or similar normally positive connection, which normally maintains the actuator and the movable contact in 0perative engagement and which, in the specific form of switch shown, comprises pivoted arms 26, 26, carrying a roller 27 andy forming a roller latch which normally, when the switch is closed, engages a notch in the upper edge of the bar 21, and holds the movable switch element in a closed position, under normal operating conditions. |The arms are pivoted to the operating lever 22 and are moved by an electro-responsive tripping device to disconnect the actuator and the movable Contact under predetermined electrical conditions through projections 28, 28a which extend from the arms into the paths of steel pins 29, 291 lying in the'paths Yof movement of the laminated cores 30, 30a

(see Fig. 3) of the overload magnets. The restraining latch which holds the actuator in circuit.y closing position acts in train or series with the roller latch which forms a disengageable connection for transmitting the lccking strain to the movable contact member, and thereby holds the switch contacts in engagement under normal operating conditions or permits disengagement at any time under abnormal conditions whether such conditions occur during the act of closure of the switch by the operator or afterward.

Theoverload magnets are made in duplicate, the several coils being` connected in operative relation to the current phases oil the polyphase circuit, and each magnet carries a frame or bundle of sheet'iron plates riveted together, as indicated at 31, 3l, surrounding the coil, the base being formed by an iron casting which is part of the escutcheon plate 25. A tubular or other guide 32, 32a is supported on the bottom of the magnet to retain the core, an adjustable nut taking into a thread on the inside of the tube, as indicated at 33, to limit the drop ot the core and adjust the points or degrees of overload at which the switch shall be tripped. The coils of the magnet are placed in series with the switch and the switch leads, or in other suitable relation to the circuit controlled by the switch and when an overload exists the cores 30, 30a are lifted and strike the pins 29, 29a. The projections 28, 28a on the arms 26, 26a, are of such a length that they will lie in the path of the pins 29, 29a when the shunt contacts hereinafter to be described are in engagement and before the main contacts of the switch have been firmly closed. 1f an overload exists and an attempt is made to close the switch, the roller 27 is automatically lifted from the notch in the bar 2l, and the latter being released, the movable contact is disengaged from the actuator and the weight of the switch parts, with the assistance of the spring actuated shunt contacts, forces the switch open, thus preventing a complete closure under an overload, since the switch member can be released notwithstanding the operator may have the handle in his grasp. In case, however, no overload exists, the

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pins 29, 29a will not have been raised and the lever 22 and the bar 2l will remain connected, the switch being held closed by the latch Q4.

To release the switch by hand, we provide a push pin 34, controlled by a coil spring, as indicated in Fig. l, the lower end ot which is in operative relation to the restraining latch 24, so that the latter may be pushed. down and the handle or actuator released., the switch being thereby opened by gravity and the other controlling forces which give the switch a normal bias toward the open position.`

1We provide, in addition to the main laminated contacts already described, a shunt contacts for each contact terminal, the construction of which is seen in Fig. 2., The contact terminals, being hollow, accommodate a phosphor-bronze rod 35 controlled by a spring 36 nesting in the hollow contactY terminal, A liange or stop on the inner part ot the rod limits the outward movememI the rod. rlhis rod or shunt contact ates with another shunt Contact 33a phosphor-bronze, screwed into the 1l the bridge piece. rlhe movable shunt tact 35 is given sufticient play to shunt contact 35 before the main contact ot the switch meet. rlhus, when 'a cl sin movement is given to the switch, the satin contacts are tiret brought together, and t overload exists, the parts are treed trom actuator or handle, as already described, be- 'tore the main contacts engage, but it the circuit is not overloaded, a continuingl movement ot closure brings the main contacts into engagement, and the switch is locked, by the restraining latch engaging the act ator, in closed position. The several springs 36 of the shunt-contacts serve to g starting movement to the switch in o, and render its action prompt, and ticularly desirable in case ot an anton release due to overload, since when the c or plungers 80, 30, are thrown nl springs give a united eect suthcient to come the friction of the engaging p.. lever system and open the circuit. represent handles by which the oil 'te be removed from the switchboaVA change out oil'when necessary or oi tion the parts.

lJVhile we have described our ments in connection with an oil sw circuit breaker, we wish it to be understood that many features apply inditl'eremd to all types of automatic switches which are selronening under predetermined electrical conditions.

1What we claim as newfand desire to se- 1.!ln an electric switch, a movable contact membeigan actuator therefor, means cure byrLetters Patent of the United States,

. 1 y, Y. "al ten., a base, a movaon- `;ch, a movable conor theretor, a latch 1 o. in electric sv, contact member, an actuator therefor, latch said actuator toy loch same to base, a latch Jtor locking saio. contact to said actuator, and elec- "vo-respoiisive isans 'f1 r unlocking aid con- .act member actuator.

ch, a base, movable contact tnator theret for resti" contact member in n sing means tiring the same to sf,

for preventing the 7 e 1.,.: 1.1 predetermined electrical conditions.

5, eec-i switch, a movable i nter, a toggle for operating said memb an actuator, means for coin and electrical switch, a base, a conber, a toggle tor one? 3 an actuator, a latch ator with said 'Vnrf said actuator to saio base, esponsivo means breaking between said actuator and connecti gle.-

,in an electrical switch, base,

able Contact member, latch pi voted to sai base, a mein engaged by said. lat a latch pivoted to said member and adapted to restrain said contacyr responsive means member.1

8. l'n an automatic magnetic circuitbreaker, in combination with 'a base separable cooperative contacts, manually perative means for closing the same, a latch on the base to engage the manually operative closing means.. disengageable means for normally maintaining operative relationship between the manually operative means and member, and electroreleasing said contact li during the ernst-ence oi means :tor breaking the contacts, and automatic magnetic means for breaking said operative relationship be' tween the manually operative member and the movable contact, substantially as described.

9. 1n an electric switch, the combination of separable cooperative contacts, manually operative means for causing their engagement, means for causing the separation of said contacts, means for normally restraining the separating means, Vdisengageable means :tor maintaining operative engagement between the manually operative means and the movable contact, and automatic magnetic means for actuating the disengageable means independently otl the restraining means..

10. 1n an electric switch, the combination of iixed and movable contacts, a contact-supporting member, spring means for actuating said member to cause the separation of said contacts, a latch for normally restraining the spring actuation, a manually operable lever for bringing the movable contacts into engagement with the lixed contacts and for causing the engagement of the restraining latch, latching means for normally connecting the manually operable lever and the contact-supporting member, and automatic magnetic means for actuating said latching means to disconnect the manually operable lever from the contact-supporting member upon the occurrence of predetermined electrical conditions in the circuit independently of the restraining latch.

11. A. circuit-breaker having make-andbreak contacts for controlling the circuit, a reciprocating member for operating the same, an operating lever, a tripping device, said operating lever being provided with means for automatically disengaging a part of it from' operative connection with said member when the latter has been fully moved to close the circuit during abnormal electrical conditions in the circuit, a stationary restraining latch for the operating lever, and means upon the return of the operating lever to normal for permitting the automatic restoration of said operating lever to operative relation-with said member.

12. The combination, with a switch member, of a toggle for operating said member, a lever, a normally positive connection between said lever and a link of the toggle, and electro-responsive means for breaking the positive connection.

13. The combination, with a switch member, of a toggle for operating said member, a lever, a normally positive connection between said lever and a link of the toggle, and electro-responsive means for breaking the positive connection upon attempted closure of the switch during the continuance of predetermined circuit conditions.

14C. 'llhe combination, with stationary contacts, of a bridging member, a toggle for cramping the said member into engagement with the contacts, a lever, a normally positive connection between said lever and a link of the toggle, and electro-responsive means for breaking the positive connection.

15. The combination, with stationary contacts, of a bridging member` a toggle for cramping the said member into engagement with the contacts, a lever, a stationary latch for the lever, a normally positive connection between said lever and a link of the toggle, and electro-responsive means 'for breaking the positive connection upon attempted closure of the switch during the continuance of predetermined conditions in the circuit.

16. circuit-breaker having make-andbreak contacts for controllingl the circuit, a reciprocating member for operating the same, an operating lever, a stationary latch forthe lever, a tripping device for disengaging the lever and member, and means for automatically rendering inoperative said lever when it has operated to close the circuit during the continuance o abnormal electrical conditions in the circuit.

17. A switch for electric currents, comprising separable contacts to open and close the circuit, means for closing them, means for causing the opening of the contacts, a locking device normally to hold them closed, and a releasing device responsive to current to release them independently of the movement of the closing means.

18. A switch for electric currents, comprising separable contacts to open and close the circuit, an operating handle to govern the switch, a latch to hold the handle closed, and an overloadreleasing device to control the switch independently of the operating handle.

19. An electric switch comprising an operating lever, a stationary detent for the lever, a movable contact biased toward opening movement when closed, means for releasing or establishing control of the circuit-closing device by said lever, and an automatic releasing device for Cutting off the control of the operating lever when the latter is held by the stationary detent.

20. iin electric switch comprising an operating lever, a movable contact, a toggle connection between the two, restraining means for the lever, and a releasing device responsive to current for freeing the toggle from the lever and thereby permitting the toggle to collapse and move said contact.

21. An electric switch comprising an operating lever, a movable contact, a toggle connection therewith, a handle for setting the toggle, and an overload release magnet for collapsing the toggle independently of lever movement.

22. A switch for electric currents, comprising separable contacts to open and close its a circuit, a member supporting the movable contacts, a manually operative member tor actuating said member, a latch tor locking the member supporting the movable contacts, a latch for locking the manually operative member, and automatic means responsive to predetermined current to release the member supporting the movable contacts after the switch has been latched closed independently of the manually operated member.

23. An electric switch, a movable contact member, an actuator therefor, a latch tor connecting said contact member with said actuator, a second latch cooperating with said connecting latch tor locking said contact member in normal position, said connecting latch intervening between'said second latch and said contact member, and means for breaking the connection between said actuator and said contact member upon attempting to move said contact member to normal position during the existence or continuance of predetermined electrical conditions.

2d. In an electric switch, a movable contact member, an actuator therefor, a lr for connecting said contact member "vit said actuator, a second latch cooperating with said connecting latch for locking said 'contact member in normal position, the locking strain being transmitted to said contact member through said connectinglatch, and means for breaking the connection between said actuator and contact 'member upon attempting to move said contact member to normal position during the existence or continuance of predetermined electrical conditions.

25. In an electrical switch, a movable contact member, an actuating member, a latch carried by one of said members and adapted to engage the other to connect them in train, a second latch independent ot said contact member and adapted to engage said train to lock said contact member in normal position,

means :tor breaking the connection between said Contact member and actuating member upon attempting` to move said contact member to normal position during the existence or continuance ot predetermined electrical conditions.

26. In an electrical switch, a base, a movable contact-carrying member, an actuator for moving said movable contact member to current-closing position, a latch for locking said contact-carrying member to said actuator, a latch for engaging said actuator for locking it to said base, whereby the movable contact-carrying member may be locked in circuit-closing position, and electro-responsive means for unlocking said contactcarrying member from said actuator upon attempted closure of the switch during the existence of predetermined electrical conditions.

27. ln an electric switch, a contact-carrying member, a toggle for operating said contact member, an actuator, a latch for connecting said actuator with said toggle, a latch engaging said actuator, and electroresponsive means for breaking the connection between said actuator and toggle.

28. ln an electric switch, a base, a contactcarrying member, a toggle for operating said member, an actuator, a latch Jfor connecting said actuator with said toggle, a latch 'for locking said actuator to said base, and electro-responsive means for breaking the connection between said actuator and said toggle.

29. l'n an electric switch or circuit-breaker, a movable contact, an actuator therefor, power multiplying means for setting the contact closed, means for disengageably connecting said actuator to said movable contact, and automatic magnetic means tor disengaging said contact trom said actuator to open the circuit independently of the actuator upon the occurrence ot predetermined electrical conditions.

30. ln an electric switch or circuit-breaker, a movable contact, an actuator therefor, power multiplying means for setting the contact closed, means for disengageably connecting said contact to said actuator, and automatic magnetic means for liberating the contact from the actuator upon attempted closure or" the circuit under predetermined electrical conditions.

3l. ln an electric switch or circuit-breaker, a movable main and shunt contact, the latter being mounted to remain in engagement until at'ter the main contacts are broken, an actuator for both movable contacts, power multiplying means for setting the contacts closed, means tor disengageably connecting said contacts to said actuator, and automatic magnetic means for liberating the contacts from 'the actuator upon attempted closure ot the circuit under predetermined electrical conditions.

lin electric' switch or circuit breaker comprising relatively movable contacts biased to open, an operating handle for closing said contacts,contact controlling mechanism cooperating with said contacts when said handle is in switch closing position to normally restrain said contacts closed and to always permit said contacts to separate and leave the handle in switch closing position, and an electric-responsive tripping device coperating with said contact controlling mechanism.

r'lin electric switch or circuit breaker comprising relatively movable contacts biased to open, an operating handle arranged to close said contacts and to be lett stationary in switch closing position, connections con In Witness Whereof We have hereunto set trollecl by said haldle fio; nornally holding our hands this 12th day of February, 1901. 10 said contacts close an or a ways permitting said contacts to separate and leave said handle in switch closing position, and electro-responsive means for controlling said Witnesses:

connections to permit said contacts to sepa- BENJAMIN B. HULL,

rate., EDWARD l/vlmiAMs, Jr,

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