US2585879A - Circuit breaker - Google Patents

Description

Feb. 12, 1952 VAN RYAN 2,585,879

CIRCUIT BREAKER Filed Jan. 26, 1949 3 Sheets-Sheet l II l I INVENTORL $16022 Van P7412 F 1952 A. \(AN RYAN 2,585,879

CIRCUIT BREAKER Filed Jan. 26, 1949 3 ShBG'bs-Shei 5 INVENTOR. J n/fion [4211 3 4212 Patented Feb. 12, 1952 CIRCUIT BREAKER Anthony Van Ryan, South Milwaukee, Wis., assignor to McGraw Electric Company, a corporation of Delaware Application January 26, 1949, Serial No. 72,916

2 Claims.

This invention relates to circuit breakers which may be of the repeating or single shot type. For instance, the circuit breaker may be generally of the type shown and described in the copending application of Anthony Van Ryan and Carl Schindler, Serial No. 585,238, filed March 28, 1945, for Circuit Interrupter, now Patent Number 2,560,831, dated July 17, 1951, and owned by the same assignee as the present invention.

Circuit breakers frequently have to handle heavy currents which produce a violent arc and this are tends to hang on or persist with consequent damage to the contacts. It has been found that the arc tends to enlarge the crosssectional area of the gaseous conducting path and that it becomes increasingly difficult to extinguish the are as the expansion of the arc, or gaseous conducting path increases. When attempts have been made to limit the expansion of the are by the use of arc chutes or chambers, it frequentlyresulted in the shattering or breaking of the arc chutes or constricting chambers, such result being particularly noticeable where the arc chutes were made of porcelain or similar rigid material. I

This invention is designed to overcome the above noted defects and objects oi this invention are to provide a circuit breaker which will quickly suppressor interrupt the arc, which will prevent rapid wear or damage of the contacts, which will prevent the building up of dangerous gas pressures, and which will control not only the volume or cross-sectional area of the arc, but also its direction to thereby prevent the are from striking or reaching metal parts of the circuit breaker other than the.contacts.

In greater detail, further objects of this invention are to provide a circuit breaker which has the stationary contacts located in substantially enclosing pockets whose walls are formed of insulating material and which are provided with gas vents to allow the quick discharge of gas and the quick refilling of the pockets with oil after, a circuit interruption, which has a constricted slot-like space through which the operating arm carrying the movable contacts on each side of thecircuit breaker passes which, therefore, has a constricted slot-like space into which the-arc wouldhave to pass as it moved inwardlyin an attempt to reach or strike other metal portions. of the circuit breaker than the contacts, and toso form this slot-like portion that it is arcuate and widens or opens outwardly towards theefront and bottom, and to provide extensive, I

cold. insulating surfaces over which the are would be forced to pass as it moved inwardly,- the constructionbeing such as a preclude the.

undue expansion of-thearc or gaseous conducting path and-to cool the arcandcontrol its direction.

A further important feature of this invention is to provide a construction whereby the .insulating walls of the chambers for the two movable contacts and the stationary contacts are flexible and will yield slightly under heavy gas pressure, thereby cushioning any shock stresses and preventing damage to the circuit breaker.

An embodiment of the invention is shown in.

Figure 1, such section being through one side.

only of the circuit breaker.

Figure 5 is a fragmentar section on 55 of Figure 1.

Figure 6 is a view of the movable contact as sembly detached from the remainder of the circuit breaker.

Referring to the drawings it will be seen that.

the circuit breaker includes a current responsive operating member indicated by the reference character I. This operating member is in the form of a plunger and is actuated as described in the above noted copending application. Suffice it to say, however, that the operating mem-. ber I is responsive to overload conditions and is forced downwardly on the occurrence of an overload. This operating member depresses a roller 2 carried by a, lever 3 which may, in reality, consist of a pair of insulating links or arms. This lever is connected by means of an insulating link t with a guiding lever 5 pivoted as indicated at 6. In reality, the lever 5 consists of a pair of insulating members. It carries a transversely extending pin 6' at its outer end to which the outer ends of a pair of tension springs i are attached. The other end of the tension springs 1 are looped over an insulating sleeve 8 through which a metallic rod or cross bar 9 extends. This rod or cross bar 9 is attached at its outer ends to a pair of insulating members or switch arms l0. These switch arms I0 are pivoted as indicated the line at l I at their inner ends and at their outer ends resiliently support the movable contacts l2.

The circuit breaker has a main U-shaped, insulating body portion !3 which has downwardly extending spaced walls M a shown most clearly in Figure 3 and these spaced walls are slotted as indicated at [5 in.Figure 1 to provide room for the free travel of the cross-bar 9 with its insulating sleeve 8.

The stationary contacts are indicated by the reference character l6 and are resiliently supported as shown.

The general mechanism, as described thus far, is substantially the same as that set forth in the above noted copending application and in itself and standing alone forms no part of this invention. This invention is primarily directed to the construction of a circuit breakf which enables the arc to be confined to a limited space and which directs and suppresses the arc and prevents the are from striking in an undesirable manner to metal portions of the circuit breaker. To "accomplish these results, the arc is confmed to arelatively narrow slot li'ke' portiony hich widens towards the outer side "of the circuit breaker and narrows towards the innerjside thereof. This 'is' accomplished by providing outer insulating plates l1 bn opposite sides of the circuit breaker and spaced from the main side walls [4. Within this space thexmovable and stationary'contacts l2 and I6 are located. 'In addition to this, arcuate, insulating members 18 are attachedto the inner walls or plates 21 and if desired'a skirtrlikeextension IS may beprovided as shown in; F i ures 1 and 2.

f The insulating members l8 project outwardly towardsthe outer insulating plates l1 and they may be formed of fiber together with theouter plates IT, so that as the arc transverses the cold fiber surfaces, a deionizing gas is evolved which further' assists in the extinguishing orsuppressmg of the mom a well knowninanner. However, it is to be noted particularly that the space, as shown for instance in Ilfigurel, orthe slot between the outer insulating walls If! and the insulating barrier members l8 is re la tively' restricted.- It is to be noted; particularly that the construction is such that a very narrow slot is provided between the members I8 aridtheircdrrespondin'g outer walls l1 and that a relatively larger, though still constricting slot-like space is left between the skirt portions I9 of themembers l8 and the outer walls I 1. The switch arms extend through the narrow slots and the movable and stationary contacts arelocated in the larger, though still narrow slot-like portions hereinabove described. Further than this, it will be seen that the construction is such that the spacing, insulating members 20' provide substantial pockets for the stationary contacts I5. PreferabIYI gaS vent holes 2! are provided through'the outer walls I] which communicate with the pockets for the stationary contacts to prevent trapping of gas in these pockets.

The mode of theoperationis apparent from the above description andit will be seen that when the pin 6' is rocked past cl ead cent'er with reference to the pivotll of the switch'arrns' ID that the movable contacts will snap downwardly and will producea quick break. Under heavy overloads the'arc will tend to persist but it'will have to traverseextended and cold insulating surfaces or faces, namely the opposed surfaces of theinsulating members '18 and 19 aha the outer'insulatihg'walls l1. Thishot only chills maintained at a relatively small value even under "heavy overload conditions.

"Itis t6 be noted that auxiliary walls or inner wallsZl are provided and that these inner walls constitute with theouter walls I! bafiles between whichall portion "of the are are confined. It is understood in this discussion that there is,

*of'cours'e', a'n arc'formed on each side of the cu. H)

circuit breaker and that the action on each arc is identically the same. It is to be noted further that the inner plates zl of insulating inaterial are spaced from theinner walls 'I 4 andiit" is und stood that'both theunner plates 2 i and the outer plates l'l' are fiekiblefandthat these is, therefore, a'yield under gas'll fessureUThis yieldfthough slight, i v s f ien ii preven shoc ist gs e ip dangerous values from bein'g irnposed onthefparts of the circuit 'breakfil and, therefore, shattering.

It will be seen that a novel circuit breaker has been provided which will linritth'e gtpan'sion' of the arc, which will confineiit to are trict'd zone, which does not produce excessive stresses on the parts of the circuit breakerand which directs the I arc' outwardly. Further "itiis its be noted that this invention provides means for presenting e d, sl n l i wo i'e i su i wi l a to the arose as to" quickly chill th'e arc andas pointed out above, new thformatioh offie npression of thearc.

'It is "to be understood that the contactsof the circuit breaker are" intendedtb Ol5 ;a e submerged tice.

Although this invention has been described in considerable detail it'is topeiiriderstqoci that such description is intended as illustrative: rather a i it n a the iiv niicn a b ariqfl y embodied and is to be interpreted as olaiined.

Iclaim: H

1. In a circuit breakeradapted to open under overload comprising a U-shaped insulating body portion, a pairof rocking switch arms located on izirl gases to thus the outer side of said U-shaped i nsulating body portion and pivoted adjacent theirlowerjends and having movable contacts carriedadjacent their outerends, a connecting bar electrically ne tin andmec an call J' ininesai we l c n act and .eq s u in w thsa dfs ch rm an mo a ,.c nta a movable lcc ta s mbl m n for mo in id mov ble .CQII- t a s m nt an quto swi q closdn iq ai o st nary conta t ocate Qnt e Outer id of sa d ss ape bo y r ion and arranged to be engaged and disengaged by said.

movable contacts, an inner and an outer insulating plate located in pairs onopposite sides :91 U-s p o o t on n artau y'housing said contacts, and a stationary arcuate ihsulating barrier located inside 'of 'the'hpa' travel of each of saidfmovabl contacts in contact with the corresponding inner insulatihg plate and spaced from the correspbndiri outer insulating plate to provide aslot forfeach of said movable contacts, said circuit breaker having pockets for the stationary contacts and said outer plates having vent holes opening into said pockets.

2. In a circuit breaker adapted to open under overload comprising a U-shaped insulating body portion, a pair of rocking switch arms located on the outer side of said U-shaped insulating body portion and pivoted adjacent their lower ends and having movable contacts carried adjacent their outer ends, a connecting bar electrically connecting and mechanically joining said movable contacts and constituting with said switch arms and movable contacts a movable contact assembly, means for moving said movable contact assembly into and out of switch closed position, a pair of stationary contacts located on the outer side of said U-shaped body portion and arranged to be engaged and disengaged by said movable contacts, an inner and an outer insulating plate located in pairs on opposite sides of said U-shaped body portion and partially housing said contacts, and an arcuate insulating barrier located inside of the path of travel of said movable contacts in contact with the corresponding inner insulating plate and spaced from the corresponding outer insulating plate to provide a slot for each of said movable contacts, said inner and outer plates being yielding and arranged to yield under gas pressure incident to the formation of an arc.

ANTHONY VAN RYAN.

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

UNITED STATES PATENTS Number Name Date 2,098,578 Hammerly Nov. 9, 1937 2,272,380 Ludwig Feb. 10, 1942 2,284,857 Bennett June 2, 1942

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