US1546272A - Electric switch - Google Patents

Description

July 14, 1925. I l 1,546,272

w. E. W'EDEMAN ELECTRIC SWITCH Filed Aug. 29, 1921 Inventor: Wayne E.Wedeman,

' bolt to a uniform bearing surface.

Patented July 14, 1925. Y

UNITED STATES PATENT lorlllctn.`

WAYNE E. WEDEMAN, 0E BALTIMORE, MARYLAND, AssIGNoE To GENERAL ELECTRIC COMPANY, A coErORATIoN QE NEW YORK. y

To @ZZ whom t may concern.'

Be it known that I, l/VAYNE E. lWEDE- MAN, a citizen of the United States, residing at Baltimore, county of Baltimore, State of Maryland, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

My invention relates to improvements in electric switches and particularly to an im- Vproved form of combined clip-block and terminal for high ampere capacity switches and to a method of making such combined clipblock and terminal. An object of my invention is to' provide a unitary structure which may be made from standard sizes of copper bars, which shall be simple and durable and which may be readily connected in circuit. Another object of my invention is to provide a structure which shall reduce heating and skin effect to a low value and insure a good electrical connection between the clip-block terminal and the bus bar or other conductor to which the switch is connected.

In an electric conducting system where a single lap joint connection is used, conductors carrying heavy currents have to be relatively thick in order to provide suflicient conduct-ing capacity and it becomes difficult to avoid undue heating. Those versed in the art, therefore, prefer to have the thickness of the conductor bars or connectors not over one-fourth of aninch as by so doing the amount of heating in minimized. Al- 'though in high ampere capacity lever switches having milled slots in the block extensions for use in bolting on connections, a multiple lap `ioint orlaminated terminal of substantially thin members in a part of the structure may be obtained, the milled slots are ordinarily rough and cannot readily or econominally be made smooth. Furthermore the milled block makes a more inflexible structure which it is diliicult properly to Consequently, the connection does not permit a uniform current density and its conductivity is also reduced.

According to my invention, l provide a' combined or unitary clip-block and terminal, hereinafter referred to as a clip-block, of mechanically substantial construction which may bel easily and efficiently connected to an electric conducting system by means of its Application led August 2 9, 1921. Serial No. 496,396.

ELECTRIC SWITCH.

laminated terminal of substantially 'thin' bars, which because of the flexibility of its laminated structure provides a substantially uniform and low current. density per unit area of bolted contact surface, which has a large radiating surface per unit volume of conductor, and in which eddy current-losses and skin effect are reduced t0 a minimum, all of which act to keep heat losses at aminimum and at the same time providea maxis a sectional view illustrating a modilication of my invention; and Fig. 6 isan elevation illustrating a modification of my invent1on.

Fig. l illustrates an application of my invention embodied in an electric conducting system, including conductors 1 arranged to be connected in circuit by an electric switch 2 mounted on a suitable base 3 of insulating material which may be a switchboard panel or the like. The switch 2 is provided with hinge andcontact clip-blocks 4 and l5 respectively, embodying my invention, the laminated extensions or terminals 6 of the clip-blocks having the conductors 1 secured thereto by 'any suitable means such as bolts 7. The clip-blocks 4 and 5 may be secured to the insulating base 3 by any suitable means such as screws S, the clip-blocks being suitably spaced apart and the lever or blade 2 of the switch, which is vhinged for movement in the hinge clip-block 4, engaging the contact clip-block 5 in the closed position.

The embodiment of my invention illustrated in Figs. 2, 3 and 4 comprises a pluralber of bars required depending upon the current to be cairie'd. lhere a clip-block is to be mounted on an insulating base as shown in Fig l, the bars 6 are bent intermediate their ends preferably in a power press so that the end portions are in substantially parallel offset planes. This provides for the necessary clearance between the base and the terminal 6 of the clip-block-for bolting the connection as shown in Fig. l.

Willen thisclearance is notneededt-he barsV 6. ate left straight. The lbars 6' yare then stacked alternately with spacer bars-Q prefeiably of the same thickness and between every tive adjacent bars 6 at one end therecf and clamped together. Countersunk holesltl Iforrive'ts 1l andscr'ew or boltholes l2.and for fasteningthe clip-block to the insulating base and-to theconnector respectively are drilled. The Arivets 1l are then placed in the holes l@ and upset thus holdingthebars together;

@The assembled stack of bars ,is now slottedprefferably in a milling machine, the slots; -14 v.beingcut to receivethe switch clips 15. These clips, whichmay havecuts 1G to providea more resilient and uniformlycontacting structurey for the .circuit closing memberof thee switchgv are, then inserted in the slcts la. *Heles 17. are .now drilled in' onebfthe bars. Gor 9,; preferably an intermediate kbai-5 transversely of the slots 14 and throiugh the inserted portions of the clips-15 andpins. ,1 8 inserted inthe holes 17; llhfefstructure thusass'embled is placed on a hot ,platewitn the lower bar in Contact with the-plate as by so doing theheat is concentrated at the riveted ends of the bars where it` is wanted and furthermore has substantially no effect on the inherent or naturalesileney of either the clips er the spread terminal of the block. When the metal has. reached the necessary temperature; the meeting surfaces of the- bars 5 and 9 and ofi tliegba'rs 6y and 9 and the cliyps l5 are sweatedtogether .in a manner ,well known to the yart .thus forming' a compact unitary strueture., For a contact 'clipebloclr such shown in Fig. 2, it is sometimes desirable toprovide blade stops- 19; seefFig. 3. These are mounted in recesses 2O cut in one or m'dreo-f theupperbars and 9 sweated therein whentheclipsand bars are sweated tog-ether.

Fig. 5- illustrates a modificationofy my invention, the bleclrbeingshewn in section on thecenter line ofthe bolthclesj .ffor securing the clip-block to the base, that is, a section similar tfo Fig; 3; The clip b loc l shown in ig., 5f is af-hinge .cli;pfbl ock having holes .2l for the hinge; .pin or bolt of af switch blade. In this inedifieation of my invention all of the bars- 6 9.are not slottedffer the' clips `l5. which may 'abut anyy one cfg-thelower such as 9, and are thus readily brought to alignment at the vupperends. Obviously it is preferable to have the' pin holes 17, see Figs. 2 and 3, in an intermediate'bar.

vFig, 6 shows a clip-block embodying a modification 4of my inventien eoniprising a plurality ofbarsI 6 and clips l5 bent and assembled .as heretofore described but without the 'spacer bars 9. This modification Iof my.inventionisv obviously adapted to carry heavy currents and as no spacer bars 9 are used the amount of material to beslotted is reduced as compared withzthe clip-block shown in Figs@ and a when constructed Vfor equivalent ampere capacity. Y'

Referring to. Figs. 1,2 and 61, it is obviousthat the free air space 22 between the surfaces ofthe bars 6 forming the laminated or spread-terminal increasesgthel additional radiating surface obtained bythe use of the ilaminated Vrterminal so that a maximum o-f-radiating-surface for a given ampere capacity isprovided. It is valso obvieusthat cliplblocks constructed inaccordance with my linvention although forming a compact unitary structure'. have .a terminal of flexible laminations `which provide for a boltedl connection .giving substantially uniform pressure between .smooth surfaces and therefore substantially kuniform current density and maximum current carryingy caf Paety- Vilhat I claim as new vand/ desire to secure by Letters `Patent ofthe United. States, i s,

l. The method of making a clipebldcl forelectric switches comprising a .p.lural;it'y of -[iat bars and switch clips which consists in; bending Ya .plurality of said bars vinter-t mediate the ends thereof sotbiatvlthe end portionsareyin substantially .parallel offset planes, riveting said flatbarstcgether at l one end, forming slots in the riveted end of one of said flat bars, inserting clips in ythefslots thusformed, drilling holes trans A versely o fsaid slots invene of said bars and through the insertedQ-ortions of said clips, inserting pinsin said) holes, and. sweating together the Ameeting.surfaces of said bars and of said :bars 'and said clipsy whereby la unitary clip-.block having a spread ,terminal is formed.

2; A clipfblocl forfelectric switches. comprisi-nga plurality ef flatv conductor bars fastened together, at one end andhaving their :free ends spaced apartk to vform- -a vlaminated terminal,Y one of saidbars havin-g slots in its .fastened end, and clips inserted Ain said slots andV secured therein by pins through holes transversely ofsaid slots in said slotted bar and the inserted portion'of each of saidclips.

A clip-block for electric switches eem-- prlsing a laminated structure `including a Iplurality of flat ybars,fastened together and slotted at one end,- and clips-inserted-in the slotted portion of said laminated structure and secured therein, said bars being spread apart beyond the clips Ato provide a terminal having separated laminations.

4. A clip-block for electric switches comprising a plurality of Hat bars fastened together at one end, and clips inserted and secured in slots in said end, said bars and said clipsbeing sweated together to form a unitary structure and said bars being spread apart beyond said clips to form a laminated terminal.

5. A clip-block for electric switches comprising a plurality of flat bars having their end portions in substantially parallel offsetplanes, said bars being fastened together and slotted at one end, and clips inserted and secured in the slots of said end, the meeting surfaces of said bars and of said bars and said clips being sweated together to form a unitary structure.

6. A clip-block for electric switches cornprising a laminated structure including a plurality of flat bars bent intermediate their ends so that the end portions are in substantially parallel offset planes and an intermediate iat bar, said bent bars being fastened together at one end with said intermediate bar between tvvo adjacent bent bars, and clips secured in slots in the laminat-ed structure thus formed, said clips and said bars being sweated together to form a unitary structure.

In Witness whereof, I have hereunto set my hand.

VAYNE E. WEDEMAN.

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