US2660637A

US2660637A - Circuit breaker

Info

Publication number: US2660637A
Application number: US128096A
Authority: US
Inventors: William A Thomas
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1949-11-18
Filing date: 1949-11-18
Publication date: 1953-11-24
Anticipated expiration: 1970-11-24

Description

Nov. 24, 1953 w. A. THOMAS ,660,637

CIRCUIT BREAKER Filed Nov. 18, 1949 Figl. Fig.2.

Inventor: William A.Thomas,

fiy fl.

His Attorney.

Patented Nov. 24, 1953 UNITED STATES PATENT OFFICE CIRCUIT BREAKER William A. Thomas, Plainville, Comm, assignor, by mesne assignments, to General Electric Company, a corporation of New York Application-November 18, 1949;Serial'No.128,096

(Cl. ZOO-88) fi Claims. 1.

My invention relates to circuit breakers and more particularly to what are termed air circuit breakers of small size.

A prime object is to provide a circuit breaker of this type that is compact, simple in construction, flexible in action, highly eflicient in operation and economical-to manufacture.

Another object is to provide a circuit breaker in which the contacts'are held closed in'such a manner that they cannot be jarred open.

Another object is toprovide a circuit breaker in which the contact pressure is much greater than the latch pressure.

Many circuit breakers are so constructed that when automatically tripped the rnanuallyactuated member must begiven two distinct movements in order to reclose thecircuit. It is one of my objects to provide a circuitbreakermechanism of this type which can be reclosed in the same manner after automatic tripping as after manual openingthat is, by one :movement of the handle.

It is a more particular object of the invention to provide, in a floating lever type of mam ually operable current responsively tripped electric circuit breaker, new and improved means for automatically resetting the current respon sive latching means after tripping so that no manual resetting movement is necessary following overcurrent trip, and to do so while providing also trip-free operation.

Another object is .to ensure a lidingengagB- ment of a movable contact against a stationary contact in closing a circuit and before breaking the circuit.

ug the thermostatic latch and 'magneticreIeaSe.

6 is an inside view similar :to Fig. 1 but showing the position of the 'parts in the position they occupy when automatically released.

The mechanism is enclosed :between the two parts 1', i of an insulating "housing suitably :secured together for instance by screws or 'rivets The angular conductor piece '3 has a circuit moves to the right.

terminal It at one end and a switch contact H at the other end. ihe othercircuit terminal l2 is secured in place by the screw It.

The switch member or floating arm it which coacts at one end with contact H has a pin andslot'connection it, Hi with the walls of the biinetal strip H5 and has-an armature .221pivoted at 23 between the housing walls. This armature has a lever arm 2 which extends at an angle to the main armature member and is under pressure of spring 25 whichbiases the armature toward the right as viewedin Fig. l. The action of the biinetal under heat or under the attraction of the magnet is to move the armature toward the left.

A fioating'ro'cker member 2'! has-a pivot pin 23 which can rotate and slide a slot 28 in the housing. This rocker has a carn-like shoulder which coacts with a cam'iic onthe switch arm it.

The actuating lever 35 is pivoted in the housing and has an arm with a cam surface 34 which coacts with a cam portion of rocker 2 In the closed circuit position, tie cam part of the lever 3i tightly holds the rocker 2'5 in the position of Fig. l where the tip of the rocker engages a shoulder 515 on thearmature and the cam 29 presses on the cam of the floating switch member is and holds the spring it under compression and positively holds the switch memher in the closed circuit position where it cannot jar loose.

It will be noted that the spring l5 presses the switch 'member !3 upwardly so that the cam 33 pressesagainst the cam 25% on the rocker 2'1 thus pressing the cam 35 on the rocker 2E the cam 34 on the member 33.

Whenthe lever 31 is manuaily turned toward the left from the position of Fig. 1 the cam 3 3 When earn as passes to the right of cam 35, the rockeri'i is free to rise in slot 28'. The rocker thus tilts countenclockwi so that cam 2S slips overcarn as on switch member l3 and thus permits the spring i5 "to tilt the switch member :13 and open the circuit with a isnap action.

In case of a heavy surge of current or in case of a gradual load above that rated for the air cuit breaker, the armature 22 will be drawn away from rocker member El so that the rocker will tilt counter-clockwise thus disengaging cain 5 from cam 38 and releasing member it so that spring 15 can suddenly throw the parts to the position of Fig. 6 and breai; the circuit. In tilting counter-clockwise after latch release the roclrer lever 2i engages a projection 33a on the right end of the camming arm 33 and rotates the operating lever 3! and the cam 33 in a counterclockwise direction to its circuit opening position.

ith the operating lever 31 and the cam in the circuit opening position, the rocker lever being still pressed upward by the spring tilts clockwise about the cam surface Gil until the pin 28 comes near the top of the slot '28. This movement resets the rocker lever against a positioning surface of the cam 33 as shown at 20 Fig. 6. From this position, the breaker can be reclosed as soon as the latch shoulder 36 is reset by simply pressing lever from the 011' position of Fig. to the on position of Fig. 1. It will thus be seen that in this construction there is an on position an oil position but no reset position of the manual lever, as is common in many circuit oi-cake In case the rocker H is at ically the main spring i5 will me e the itch l3 open the circuit even if the actua ig lever is manually held in on position. this case the rocker lever 2i tilts cod, tcr-clcclrwise after latch release under the action or the spring it, pr ssing against the cam and errgaging the tip 23a of the can: arm the lever is then released, it will fly to the onf po'ition because of the pressure applied to "'lt'i 33a by the rocker lever and the rocker lever 21 will then tilt clockwise as before about cam projection until the pin 2:? is near top of the slot it. The mechanism is then ready to reclose the circuit manually, being in the position of Fig. 6.

This arrangement ensures a trip action in it oh the circuit is broken at a maximum speed v -en the breaker is re eased either manually or automatically. In either case the cam shoulder is first released for movement upwai to the right. The spring It, pressing the inenicer l3 upward a. rai es the pivot pin is o to the top of the slot i l. movement of the pin it causes tl tact tip to slide along the surface of the eta i thus preventing tendency a then slides over .lLLS the the shoulder to raise the rign circuit positon of The has its mash mum power at the very start of openin movement so as to start the sepaation of t an high speed. This result in superior interruption in a small ci 'cuit brea er of this type. In fact such a switch has proved to be several tir s as fast as ccinrner :ially comparable break- It possible with this type of breaker to obtain contact pressure up 0 seven or the latch pressure whereas in other small breakers the ratio is as low as one or two to one. The gases resulting from the re formed in the chamber to when breaking the circuit are allowed to escape through the tortuous ii formed in the housing '1. Ihis labyrinth is further divided into several compartments by the perfo- 4 rated

fibre bafiles

42 and 43 which act to gradu' ally cool and lower the pressure of the gases resulting from the are. This arrangement ensures a safer breaker free from the usual dangers from fire or flame from the exhaust port.

I claim:

I. In a circuit breaker, a a stationary contact mounted on a rigid novable switch arm having a pin and connection with said base at one and having a movable contact at the other end cooperable with sta tionary contact, pin and slot connection. providing transverse sliding pivotal inovcment of said arm, a spring said switch intermediate movable contact said one end and biasing said switch aria to an open ircuit position, and manually operable carn ming means engaging said swirl, arrn intermediate said oontact and said sprin to for *e to a circuit closing position locii biasing action of said spring, said release of said manu bio mean st sliding said one end of said switc 3. arm tieversely thereby to slide contacts one upon e other and then separating said contacts by rotation of said switch arm about said one end.

2. In a circuit breaker, a stationary contact, a rigid movable switch arm hav ng at one end a movable contact cooperating with said ed con tact, means mounting said switch arm at his other end for pivotal sliding movement in a direction transverse of said switch arm, a spring one-aging said arm intermediate its ends and biasing said arm to an open circuit position, switch arin having an inclined camining surface inte. said spring and said one end, and manna y operable actuating means including a pivotally mounting camming projection engaging inclined surface and shape-cl to permit abrupt cir-- cuit opening movement of said switch arm, said switch arm when released by cast 1?; projection first sliding transversely on said pivotal mounting to slide said contacts one upon other and then turning on said pivotal mounting to separate said contacts.

3. In a circuit breaker, a base, a switch memoer movably mounted on said base, cooperating switch contacts controlled by said switch member, means biasing said switch member to a circuit opening position, a rocker lever mounted on said base intermediate its ends on a sliding pivot for movement into engagement with said switch member, current responsive means releasably securing one end of said rocker lever against movement, an actuating cam mounted on said base on a fixed pivot and having an actuating projection engaging said rocker lever to tilt said lever about said one end thereby to move said switch member between circuit opening and circuit closing positions, said rocker lever when released with said actuating cam in its circuit closing position tilting about said sliding pivot to release said switch member and engaging said cam to move said cam to its circuit opening position, and positioning means on said cam engaging said og UPOU rocker lever when said can", is in its circuit openleasably securing one end of said rocker lever against movement, a manually operable actuat ing cam rotatably mounted on said base and having a projection engaging said rocker lever inter" mediate said one end and said slidable pivot to slide said pivot, said rocker arm when so moved engaging said switch arm to close and open said contacts and when released by said current responsive means rotating on said slidable pivot to release said switch member for contact opening movement, means engaging the other end of said rocker arm when released by said current responsive means to rotate said actuating cam to its circuit opening position, and a positioning surface on said actuating cam engaging said rocker arm in said circuit opening position of said actuating cam to position said rocker arm for automatic resetting of said current responsive means, whereby normal manual circuit closing movement of said actuating cam after current responsive opening of said contacts recloses said contacts.

5. In a circuit breaker, a base, a rigid movable switch arm mounted on said base for pivotal movement about one end, circuit controlling means actuated by the other end. of said switch arm, a spring fixedly mounted on said base at one end and engaging said switch arm to said arm to a circuit opening position, a rocker lever mounted on said base intermediate its ends on a sliding pivot for movement transversely of the length of said switch arm, said rocker lever having a camming projection engaging said switch arm intermediate said spring and said other end of said switch arm, current responsive means releasably securing one end of said rocker lever against movement, and an operating lever pivotally mounted on said base and including an actuating cam engaging said rocker lever intermediate said one end and said sliding pivot, said operating lever including a portion positioned to be engaged by said rocker lever when released to turn said operating lever to its off position and said actuating cam having a portion engaging said rocker lever when said operating lever is in said off position to position said rocker lever for automatic resetting of said current responsive means.

6. In a circuit breaker, a base, a stationary contact mounted on said base, a rigid switch arm, means mounting said switch arm on said base for transverse sliding and pivotal movement at one end, a movable contact carried by the other end of said switch arm for cooperation with said stationary contact, a spring fixedly mounted on said base at one end and engaging said switch arm at a point intermediate its ends to bias said switch arm to a circuit opening position, a rocker lever disposed in substantially parallel spaced relation with said switch arm and having a camming projection engaging said switch arm intermediate said spring and said movable contact, means mounting said rocker lever on said base for transverse sliding and pivotal movement at a point intermediate its ends, current responsive means releasably securing one end of said rocker lever against movement, and manually operable means including a rotatable actuating cam pivotally mounted on said base and having an actuating projection engaging said rocker lever intermediate said one end and its pivotal mounting, said actuating projection normally tilting said rocker lever about its said one end thereby to press said camming projection against said switch arm and move said switch arm to circuit closing position when said actuating cam is moved to a circuit closing position and said rocker lever when released by said current responsive means rotating about its intermediate pivotal mounting to release said switch arm for circuit opening movement, a second projection on said actuating cam disposed for engagement with the other end of said rocker lever when released by said current responsive means to rotate said actuating cam to a circuit opening position, and a positioning surface on said actuating cam to engage said rocker lever and position it for automatic reset of said current responsive means when said actuating cam is in said circuit opening position.

WILLIAM A. THOMAS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,184,372 Van Hoorn Dec. 26, 1939 2,297,320 Platz Sept. 29, 1942 2,300,884 Gano Nov. 3, 1942 2,308,401 Taylor Jan. 12, 1943 2,328,458 Jackson et a1 Aug. 31, 1943 2,363,606 Maseng Nov. 28, 1944 2,416,164 Ellis et a1. Feb. 18, 1947 2,424,909 Adam et a1 July 29, 1947 2,447,652 Jennings Aug. 24, 1948 FOREIGN PATENTS Number Country Date 41,861 France Jan. 26, 1933 666,338 Germany Oct. 17, 1938