US1645905A - Provements limited - Google Patents

Description

Oct. 18, 1927.

R. W. GREGORY ET AL ELECTRIC SWITCH OR CIRCUIT BREAKER Filed Dec. 21, 1926 2 Sheets-Sheet 1 WW//%WWW Oct. 18, 1927. r 1,645,905

R. W.- GREGORY ET AL ELECTRIC SWITCH 0R CIRCUIT BREAKER File o1 Dec. 2 l. 1926 2 Sheets-Sheet 2 Z i j! 227/7 13 m mm, M? M,

61 DZ MM 4% Patented Cct. 18, 1927.

- STATES PATENT OFFICE.

-BICHABD WALTER GREGORY, or HEXHAM-ON-TYNE, AND LEWIS coLm GRANT, or

HEATON, NEWCASTLE UPON-TYNE ENGLAND, ASSIGNORS TO ELECTRICAL Int- PROVEMENTS LIMITED, or NEWCASTLE-UPON-TYNE, ENGLAND, A COMPANY or GREAT BRITAIII.

v ELECTRIC SW'ITCH OR CIRCUIT BREAKER.

Application filed December 21, 1926, Serial No. 156,194, and in Great Britain March'3, 1928.

' jl his'inveiition" relates to electric switches or circnit-brealrers and particularly to the :con'tactsfwhether main or auxiliary. where arcing takesplace when'thc switch is broken.

" In switches or circuit-breakers dealing with heavy 'loads'this arcing is a serious factorand"many'suggcstions have been made to reduce the sizoof the arc and its duration:

0 l E;A1i electrios witch or circuit-breaker according tothe presentinvent onlias contacts whic'ln-"when the switch is opened, move "away ii 'oppos'itedirections froman 1nsulate'd lnetaltbo'dy against which they both r'e'srwvhn the switch is 'closed.

-(tact and'ftlie' other between the body and the- This body'i'spreferably fin the'form of a {"whensuch arnisare employed. Further. it

"- arcsfi'fefoiie between the body and one coin other cohtactfThese arcs are thus in series 1Andtlier'- featurefwhich inay 'be' provided in a snjitchor circuit-breaker according to 0 this invention is a conductor placed out of direct connection with the moving contact but adjacent to its path of motion. There are preferably two of such conductors disposed at equal or unequal distances from the central metal body or plate. Their action 'is'to cool the are still further when, as in the case of a heavy and strong arc, it extends from the central body to the moving contact as such contact passes the conductor. In such 'circnnistaimes the are will he established momentarily between the plate on the one hand and'thc conductor and moving contact on tlie other'hand. The are will be cooled and will almost immediatel be extinguished as the moving-contact passes further' on its path 'away from the conductor. Momentarily there willgih such a case, be -three or four arcs in series for instance, two on one side/ and one or two on the 'other.'

The plate. the moving contacts and the conductors when such are provided, are all prefcrably made with smooth rounded surfaces to avoid edges or points, and thus keep the are cool by preventing it from'raising described in the specification of United States Letters iPatent No. 1,366,791 granted to R.- W. Gregory, one of t he present-applicants, wherein the movin cont-acts' 'are at the 'end of upwardly ez rtending :pivbted arms arranged so as to 'draw buttli are more or lesshorizontally so that the vapolirs can rise freely'ithrough'the oil iniwhic h'the switch'is immersed to a* 'vent':-

W'hen the inventionis so applied-the'metal body or plate" is fixedso' as to' be' between" the contacts when they sil e -closed on to it, and

its presence 5 not only "cools' the arc-(but effectually prevents any 7 tendency iorg" it to travel downwardsfi The intermediate conductors, if used, are preferably placed slightfictsitO cool the arc anddivides it into two ly above thefsubstantial-ly horizontalpaths through which thecontactsmove'.

-' When the contacts flcarried'by thepivote armsare primarily only a'rcing' contacts,- the mainicontacts may-'be 'in the fortti of fixed brushes bridged byl a cont-act" bar' 'which' is moved away from "them by appropriate mechanism immediately beforethe arcing contacts are opened. *1

In the accompanying drawings, Figure 1 is an elevation partly in section of one construction of switch according to this invention; Y

Figure 2 is a portion of a sectional elevation taken at right angles to' Figure 1, and Figure 3 shows the principal parts of the switch as illustrated in Figure 1 but in different positions. v

In these figures -A;are arcing contacts mounted on bell 'cranklevers A pivotedat A and having their shortarms-pivot'ally connected-as at A to; the upper ends of insulating rodsB. -'The "lower extremities of these rods, or-caps borne by-them, have pins C passing through them and through with two fixed-main contacts brushes F supported on brackets F secured to the main conductors G which pass down through hollow insulators from the top of the tank J. The brackets F and the dcpendentconductors G are braced by a pair of insulators K and by a central insulator K which passes through ,the forked lower por,

tions of the contact-bearii'i'g 'armsbf the crank levers Flexible conductors L join these contact-bearing arms with the adjacent braokets F i. c. with the conductors Below the bar I) is a leaf spring M whoseends bear against the pins 0.

It will be seen that when the switch is closed, as in the position shown in Figure 1,

'the arcing contacts A do not beardirectly against'each other but against a metal body or tongue N piv otally supported as at N from an insulator N This tongue N in the construction illustrated is provided with a 1 spring NF; which tends to deflect it when free to the right-hand side ofthe centre line of- Eigure 1.: In;this position, which is made detinitei by the provision of a stop N, the

tongue N is shown in full lines in Figure 3. As willbe appar'ent'from the drawings,

when the operating rods E are pushed down by some suitable mechanism, not shown but main contact F is moved downwards. the first-,partof that movement the arcing of any usual; and known construction, the For contacts A are not separated but remain -pre ssing on the two' sides of the tongue N.

Shortly afterthebeginning of its downward movement the main contact-F separates from :the fixed-brushes F and-assumes say the position shown ,in chain lines in Figure v3. ;F.urther downward opening movement of the, switch then begins to swing the bell crank levers 3A outwards to separate the 'arcing contacts A. The left-hand arcing contact will then at once separate from the tongue N but the right-hand arcing contact will not separate from the tongue N quite simultaneously as the tongue will follow up the motion. of the arcing contact under the influence of the spring N? until stopped by the projection N. Continued opcningmovement swings both the arcing contacts outwards until they reach their final positions as indicated in full lines in Figure 3.

Apart from the initial advantage of having a metallic body or tongue between the above mentioned under the action of its spring, the plate 0 will be slightly nearer to the tongue than the plate Owill be. This is found to be advantageous in' practice.

As shown in the drawings thearcing contacts A; the tongue N and the conducting plates 0 -O are an provided with rounded surfaces. This helps to attain the general object of theinyention which isthe construction of.a 'switch wherein the arc shall be cooled as'muchas possible to facilitate its ready ex net en- 3 It is to be understood that the details of construction may be varied without departing from the spirit; of ;t he;.invention.. The construct-ion illustrated isg given merely; by way of example'and obviously details such as the mounting andmoveinent of the con tacts might be altered considerably within the scope of the appended claims.

lVhat we claim as our invention and desire to secure by Letters Pat ent is 1. In an electric switch the combination of fixed and movable main contacts, means for separating such contacts by downward movement of the Jnovable contact, arcing contacts, an insulated metal body between said arcing contacts a ainstwhich body both arcing contacts rest w 1en closed,and anoperative connection between s aid movable main contact and said arcing contacts acting to cause thearcing contacts to move away from the metal body inopposite directions when the main contacts are opened.

2. In an electric switch the combination of fixed and movable main contacts, means for separating such contacts by a downward movement of the movable contact, pivoted arms extending upwardlyto givea rapid and long substantially horizontal break, arcing contacts mounted on said arms, an insulated metal body between said arcing contacts against which body both said arcing contacts rest when closed, and an operative connection between said movable main contact and said pivoted arms to cause said arcing contacts to move away in opposite directionsfrom said insulated metal body when the main contacts are opened.

3. In an electric switch the combination of movable contacts, an insulated metal body between said contacts againstwhich body both said contacts rest when closed, and an insulated conductor adjacent to the path of motion of each contact between its closed and open positions.

4. In an electric switch the combination of pivoted arms extending upwardly to give a rapid and long substantially horizontal break, contacts mounted on said arms. a metal body mounted between said contacts in such a position that they close upon it, an insulating support for said body. and an insulated conductor adjacent to the path of motion of each contact between its closed and open positions.

5. In an electric switch the combination of fixed and movable main contacts, means for separating such contacts by a downward movement of the movable contact, pivoted arms extending upwardly to give a rapid and long substantially horizontal break, arcing; contact-s mounted on said arms, an insulated metal body between said arcing contacts against which body both said arcing contacts rest when closed, an operative connection between said movable main contact and said pivoted arms to cause said arcing contacts to move away from the metal body in opposite directions when the main contacts are opened, and an insulated conductor adjacent to the path of motion of each arcing Contact between its closed and open positions.

6. In an electric switch the combination of fixed and movable main contacts. means for separating such contacts by a downward movement of the movable contact, pivoted arms extending upwardly to give a rapid and long: substantially horizontal break, arcing contacts mounted on said arms, a pivoted insu'lated metal body between said arcing contacts against which body both said arcingcontacts rest when closed, a spring tending to move said pivoted metal body to one side, and an operative connection between said movable main contact and said pivoted arms to cause said arcing contacts to move away from said insulated metal body in opposite directions when the main contacts are opened.

7. In an electric oil-immersed switch the combination of two fixed main contacts, a movable main contact cooperating there\ ith, a support for said movable main contact, operating mechanism for moving said support downwards and upwards to open and close the main contacts, pivoted bell crank levers having arms extending upwardly, arcing contacts mounted on said arms, a pivoted insulated metal body between said arcin g contacts against which body both said arcing contacts rest when close-d, an insulated conductor adjacent to the path of motion oi each arcing contact. between its closed and open positions, and operative connections be tween the support. for the movable main contact and the pivoted bell crank levers acting to cause the opening of the arcing contacts immediately after the opening' of the main contacts.

In testimony whereof we have signed our names to this specification.

RICHARD WALTER GREGORY. LElVIS COLIN GRANT.

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