US2537348A

US2537348A - Fused dropout cutout

Info

Publication number: US2537348A
Application number: US40756A
Authority: US
Inventors: David C Hubbard; William L Hollander
Original assignee: AB Chance Co
Current assignee: AB Chance Co
Priority date: 1948-07-26
Filing date: 1948-07-26
Publication date: 1951-01-09
Anticipated expiration: 1968-01-09

Description

Jan. 9, l1951 D. c. HUBBARD ET AL v 2,537,348

FUSED DROPOUT CUTOUT Filed July 26, 1 948 2 Sheets-Sheet 2 Another object is the provision of an improved device of the class described having a mechanism that is unaffected by accumulations of ice and which is adequately protected from such accumulations as may occur.

Another object of the invention is the provision of a device of the class described which gives a visual indication in the open position whether the device has been operated automatically indicating the existence of a fault, or whether the device has been opened manually, indicating the purposeful de-energizing of the circuit for repairs or other reasons.

Another object is the provision of an improved contact structure which is self-aligning with relation to the trunnions on the fuse tube unit, and the provision of stops and buffers to arrest the reaction that is due to the jet action and to prevent overstressing the contact springs.

Another object is the provision of an improved fuse tube unit and support therefor, which is so constructed that the forcible closing of the contacts by slamming the fuse tube into position, tends to force the ejector arm against the bottom of the fuse tube rather than to cause the arm to place additional tension on the fuse link element, thus eliminating the shocks that are imparted to the fragile fuse link in the devices of the prior art.

Another object of the invention is the provision of an improved ejector mechanism for the fuse leader in which the cable is so arranged that it does not slide over the end of the ejector lever as the lever moves, thus reducing or substantially eliminating the friction which would be caused by such a sliding action and which would resist the ejector lever operation.

Another object is the provision of improved contact arrangements by means of which the contact fixtures on the fuse tube unit are resiliently urged into engagement with the fixed contact arms, and by means of which the contacts are self-aligning with respect to the trunnions on the fuse tube unit, and by means of which the longitudinal pressure on the fuse tube which sometimes causes bending, after a long period of time, is substantially eliminated.

Other objects and advantages will be apparent from the following description and the accompanyng drawings, in which similar characters of reference indicate similar parts throughout the several views.

yReferring to the two sheets of drawings accompanying this specification.

` Fig. 1 is a fragmentary side elevational view in partial section, showing a fused drop-out cut-out embodying the invention;

Fig. 2 is a fragmentary side elevational View showing the position of the parts of the lower end of the fuse tube unit after the fuse has blown;

Fig. 3 is a fragmentary sectional view on the plane of the line 3-3 of Fig. 1, showing the electrical connector by means of which the lower contact arm is connected to a wire cable or other conductor; and

` Fig. 4 is a fragmentary sectional view taken on the plane of the line 4-4 of Figure l, looking in the direction of the arrows.

Referring to Figure l, IIJ indicates in its entirety the fuse drop-out cut-out assembly, which preferably includes a supporting structure II and fuse tube unit I2 carried'thereby. The supporting structure IIl may be embodied in the single insulator type shown in Figure 1 or it may "zoN be carried by two insulators in the manner shown in the prior application of David C. Hubbard, Serial No. 11,076, filed February 26, 1948, Fuse Drop-Out Cut-Outs.

The single insulator type of Figure 1 has a porcelaininsulator I3, which is formed with a multiplicity of peripherally extending skirts I4 separated by grooves I5, and the insulator preferably has a reduced cylindrical portion IS-adjacent at its middle, and additional reduced cylindrical portions I'I at each end. The middle cylindrical portion I6 of the insulator is surrounded by a metal band I9, the ends of which are provided with two laterally projecting attaching ilanges, having a screw bolt 22 passing through them and clamping them together.

The clamping band I9 is a part of the structure used for supporting insulator I3 from a crossarm or other support substantially as disclosed in our prior application of the same title, filed March 8, 1948, Serial No. 13,704.

Thus the insulator I3 is adapted to be supported from a horizontal cross-arm in a tilted position, so that the fuse tube unit I2 will extend diagonally upward and away from the cross-arm in such manner that whenever the fuse tube unit hangs only from the upper contact arms, it hangs in a vertical position by gravity. By reason of this position of the insulator and fuse tube unit, the fuse tube unit is so supported that it may pivot upon either the upper trunnions or the lower trunnions by gravity to a position which it will ret-ain by gravity.

The reduced cylindrical portions I'I at each end of the insulator I3 are bordered by one of the insulator skirts on one side, and a radially projecting rib 35 on the other side, forming a groove for receiving the clamping bands 36 which carry the upper and lower contact supporting arms 38, 39, substantially as described in our prior application.

The contact supporting arms consist of a pair of laterally extending flanges or straps extending from the clamping bands 35, and adapted to be secured to contact fittings by being provided with aligned bores for the

screw bolts

43,44 below, and I2I), I2I above. f

The lower contact fitting 46 comprises an elongated conductive metal casting provided/with a flat attaching iiange 45, which may be received between the flanges of the arm 39 on band 36 and secured by

screw bolts

43, 44. Lower contact xture 46 has a hood or partial housing 4l for supporting the lower contact trunnions 63 and for enclosing the ejector and contact mechanism, and for protecting the lower mechanism from rain, snow and other adverse weather condi-` on the shank of the bolt which pulls the head against the conducto-r.

A' similar connector 49 is carried by an upwardly projecting flange 52 carried by thev upper contact fixture 53. The hood 41 has parallel side walls 54, a curved top wall 56 and a iiat rear wall" 5l, Figure l, leaving the bottom open between the side Walls 54, when the fixture is installed properly, as in Figure 1.

The sidewalls 54 of the hood 4T are providedv` withthe laterally -inwardly projecting integral 5: cyllndtibaltrunniona, trcnwthefside :wallfsinaalignmentifwithzeacmether' and?. toward? .each other; terminate'. short dif each other to permitthe1`eje'ctor leverrofthe tube' unit Ifto move-between these'dtrunnions G3i. j

vThe-` vinner' ends B ofi the tr-un'nlions 31 are spaced' -frorrr-eachl other suiliei'errtl'yf'tovpa'ssy the relatvelyf'flat fila-nge andE re-eriliorcingi portons lofthe ejector arm'S 8'; wlliichfis1pNota-ily.mounted extends along the inside -off' its-itop'walli which is intially` spaced vlfrom thev'topwa' 'eing tensioned whenl bentfupward- Aas-'sliowrr in 'Figure l. This leaf" spring F8 passesfthrougfhan apen@ 1* ture'inthe rear wallf51, andl'issecnred'to a= hbri-V zontalflangell byimeans'fota Irivet 1111". Sprl L1g ES urges4 the contact 'porti'onsofitheE fuse itnbe unitiy I 22' resilientlydagainst the t'rrmnions@ A153. l*

Theffusetubaunit Tlcomprises 1an insulat g tube 12; Vp'ref'erably having an autore-portion vwhich is adapted to resist exposuretpwea'tlier;

and anv inner portion "Il: whichL klisadapted .to resistburning by the -heat^ generated-fin the meltjd irrgfoff the-inse, 'these' twoportions-*b ng` `inte--y graily-"cemented':togetherto form a sngletube:

Ht' its lower'end the' fuse' tubeTZ supportstlie contact Afl'xi'jure 15,- wliicl'r lhas an' 'upwardlyopenl tubtilar member- T6 for receiving the vlowerv` endv` oitlre lfuse tube.A Thefuseetubesisicedlv secu-red: the ferruleY 161offtl-re l'owerxtnre'ii by' alpair of screw bolts 11 threaded into boresn'tl're'fr'- ruife; and penetrating yonly"partly-f"into` the` thick` tube- A1i! so that theh inner'ends of the Lboltsj 11i The -fuse"ttbe*terinitiatesn at 18j, inside the blast' chute 19, and is'open at its'iower'endwhereiii isconstantly protected'from the weather'bv hanging-downward; eitherv in then positionA ofFigure '1 or after blowing -ofthe fuse in the verticalposi- 'm tion-v of Figure 2. "The" lower fixture '15 supports the integral* blastchute 19'; which hasl va pair of parallel -sidewalls 8U; a topwall81lushwit the end18 of the tubeand adiagonallyextenjding rearwall 82fwhic'h extends over towardthecen.- t'ero the' tube12`, and" is adapted to" deflect gases 'downwardl'y' and toward the right away'l fromtliefaceofltleoperator:

The 'sidewallsv .88 'of' the blast jclu'teIllv eacl support anv outwardly projecting-cylindrical stud? 83, which` is adapted to provide tl'iepivotal sup'' port and point oi attachment of: a, fuse. leader guard* adapted' toy receiveA `anli'-"`l1ol"d the cabl'e` of." tl'leffnse' whentheiuseis. blown. Thef'fuseleader guard'formsno partoftthe presentinvention'; and may besubStarii'allyl as ishiown' inthefpriorpaterfi toAly David Hubbard, No. 2`,461',898'; dated'e'b: 151 1949i 'The lower-xture 15'1i's formed' withtanintegral ringY 8M located on upperf'sida vFigure for reception of the laterally projecting operating plrr ofa disconnect ystickv upon which( :the fuse unit" IZ-is hung" whenit 'is-to' beinstal'ed` Lower' fixture 15"-also hasan'integral?substantially'cyliir dricai body portion" 85'; below`- the 'riirrgjMI5v and provided with a cylindrical'iboreSdforreceivlng an ejector spring 81.

The ejector spring comprises a helical coil spring reacting sat; itsairightnerrd on I,the:end-of bere' 8i,y andiV engaging;v a'tfits': lett` yerudl` the'- washer. 88 of. ani-ejector stiaut-ll` Ejecton-strut comprises afstiffiffstripo s'lheetrmetal; bavi'rfgL a1 reduced' endVv .SIT which: passesthrough an apen-3 ture` ithe-` insulatingf'wasl'er 818 and Jlilla/*ingr*ati` ,onafbathilsidesxothe lejector lever '88 attL its; :night edge. Thus the ejector spring 8in-mees thesejec;4 'tor ilevertowardithecleft; inzFigure 1=,.`:by means oitlie'fstrut;

The upper-wall or the cylimlric'a'lformation-185i' isrlextended=tbward the left to form apart-olf! .a root Q12.; which curves upwardly under. the top walleo'ftbe hood to' make sure that' 'the hood overlaps and drains on the lower fixture 15f1at a.

onitheftnbeunitilfl 150i point'h where the` water' will not.V run into the Theffhoodfl' supports a leaff sp i519'. wliili Y mechanism:

'Referring to Figure?, :the laterally projecting portion; Sti :ofthe lowerv iixture.y 15' is provided with-a rectangular rslotf94 open-toward fthe left',

ejfectorlever l68 which "isI pivot'edon the rivet 975@ The"rivet 96',` v`which forms the-pivot for therejector: liever, alsof-nasiy a later-ally` projecting :cylinf leader 98 may bewrappedfwhenthe .fuse-'is in stal'led'inrthe' fuse uniti 'I 2.

Lower' lcontact-fixture 15" also-has a later-all-"yy cular button at the top adapted to'be clamped against* an end surface on the upper xture IUI by means' of``the internally threaded cap |822 The fusible portion of the-fuse is located in the upper "lend" `of the `tube TZ, and' is connected4 to the stranded copper wire 'leader' `cable wirev S81 wli'iiih extendsidownwardly out of thelower end of"l the tube T2 and out of the blast chute 19?;

Fuselea'der98 passes around the endI H33! of the eie'ctor lever 6B; and is located ina-'groove IM in the bottom or end of ejector lever B83 From they groove IM' Vthe leaderl l98 passes about thest'ud 91, and its end' vis passed about the stud 99 and clampedby the thumb nut |80. 'When the fuse leader is so installed, the eiector lever G8' is 'tensionedg that is; it is moved from the position of 'Figure 2 'to' that of" Figure l, compressi-ng; the spring 81 and" 'causing'V 'the fuse ejector lever 68 toplace- 'atensiongon 'the fuse leaderf'. q Y

The* ejectorlever B8 is bivo'ted inthe 'slot' 94" between tlfefparallel`r portions |85 of the-flower iik-ture T5, andfejec'tor leveriliY has a relativelyr flatbody'fflange F06' which is Irelatively thin but is" re-enforcedby a thicker border ange Tlieyovalf' aperture H18" (Figure 2) in the eject- 'tor1V lever flangeV |86 is` merely for convenience in machiningr adjacent surfaces; comprising the" dat' inner vsurface F09* and the cylindrical: en'd; surface III) ona pair of laterally projectingA guide flanges I'IIf'. These guide iianges'; whichj arev on'both sidesv of' the ejector Vlever 68, also have downwardly extending lips H2; with` a diagonally extending -face I I3v for guiding the trnnnions 631 into proper position; The lateral thickness #off the ree-enforcing border flange AIII'I.l i'sf'suchV thatit passes between the ends 6E/61 of 'th with the laterally projecting curved contact members 'I-I. These arcuate Contact members have "lower 'partially cylindrical" `surfaces H55" for#.engagingA the trunnions- 63; against which* 'er trunn'ions which arey carried by the vsurged'V by VJthe vspring` U81 which' 'bearst on the top of the lateral extension 93 at the flange 92, Figure l.

The side webs of the lower contact xture are extended toward the left, in Figure 1, to form the curved camming surfaces H6, which engage the spring 69 in the installation of the fuse tube unit I2 and urge the fixed contacts H4 into proper engaging position with the trunnions 63.

rlhe ejector lever 68 is also preferably provided with a pair of laterally projecting hammer ylianges H1, vhich are beveled at H8 on the lower left corner to provide a sharp edge at H9. The sharp edge H9 is so located that'it is adapted to penetrate between each trunnion 63, and each xed contact H4. Thus the ejector lever has a sharp hammer Iiange, which is forced between the fixed and movable contacts to separate them when the fuse is blown and withdrawn by the ejector lever.

Referring to the upper contact supporting arm 38, it is supported on the insulator I3 in substantially the same way as described with respect to the contact band 36 at the bottom. The two ilanges of the arm 38 have apertures for the screw bolts |211, 2| which also pass through an attaching flange |22 on the upper contact arm fixture 53 to secure this fixture to the upper arm 38.

The lixture 53 pivots on the bolt |2| by reason of the clearance provided by an enlarged aperture |23 inattaching iiange |22 surrounding the bolt |20. This pivotal movement provides a predetermined amount of adjustment of the jaws of the upper fixture 53 to accord variations in length of the fuse tube unit -vI2, and still bring the upper trunnions |24 into good contact engagement with the upper fixed contacts. f i The screw bolts I 20, I 2| are provided with an aperture |42 like the ring 84, of sufficient size to pass the head on the laterally projecting pin of a disconnect stick by means of which the fuse tube unit l2 may be manipulated. f

Ring I4| is used for operating the unit as a disconnect by merely pulling out and disconnecting the upper contact, while the unit l2 pivots on the lower trunnions. Ring |4| is also used in the installation of the fuse tube unit to swing the unit upward from a position where the tube unit I2 depends from the lower trunnions 63 to the position of Figure 1. 1

The parallel side walls |30 of the upper contact fixture are spaced suliiciently to receive the trun.

spring Alock -washers, thereby taking up any j rattling and preventing the contact xture 53 from pivoting too loosely.y l

The upper contact xtme 53 may comprise a cast metal member, and it is preferably formed with a-housing having a pair oi parallel side walls |30 integrally joinedA to a curved top wall |3I, and a depending back wall |32, forming a hood which is open at the bottom for receiving the upper end of the -fuse tube unit I2, and for protecting the Ycontacts and upper mechanism from snow, rainand other weather conditions.

. The upper contact fixture |0|, on the fuse tube unit 2, has a cylindrical body |33, with a cylindrical bore for receiving vtheafuse which is again secured in place by a plurality of screwbolts arranged like the sorewbolts 117 of the llower fixture. Y has a'reduced cylindrical extension |35 which is `threaded externally to receive the internal f threads of the cap' |32, which is closed at its upper end |36. Y

. Therev is a bore in fuse tube 12 for receiving the fuse andl its leader. At the upper right vcorner of the cylindrical portion |33, Figure l, the cylindrical body |33 is provided with a pair of laterally projecting cylindrical trunnions |24, and these trunnions |24 form the upper contacts carried byfuse tube vunit I2.

At the lower part of the side walls |30 there is a similar downwardly and outwardly flaring surface |46 for engaging the bottoms ofthe trunnions |24, and aiding and guiding them intovenrgagement with the contact fingers. y

The two innermost contact springs |56 have straight portions extending forwardly and-terminate in partially cylindrical trunnion-engaging,Y portions engaging the trunnion |24. Thereafter.'v these contactsprings |56 flare outwardlylike the surfaces |44, |46, to aid in guiding the trunnions between the springs. i v- The two outermost leaf springs |51 rhave` straight portions extending outwardly toward the trunnions and partially cylindrical portions at the trunnions engaging the outside of the springs |56, forro-enforcing the springs |56 and improving their tension. VAll four vsprings are ini-f. tially tensioned toward each other s0 that they tend to close and present asmaller opening, which is spread when the trunnions |24 enter the flaring spring |56. l

The trunnions |24 are retained in the partially` cylindrical latching formations of the leaf springs |56,V into which they can be pushed by meansof a disconnect stick or from which they can be pulled with .the same tool.

Operation The mode of manipulation and mode of opere.

ation of the mechanism is as follows:y A fuse with its leader 90, arranged as shown in Figurev 1;-y is first placed in the fuse tube unit I2; then-l ejector lever 68 being pressed up against the end*- of the balile wall 82 tensions the spring-the leader? passing through the groove |04 around the pin- Si, andrbeing' securedfby: means :of thumb nutrtil-i.

A predetermined tens'ion 'is- .thus placed. upon.

the-fiuser leader .9.8,itendingato'withdraw this leader fromithe .tube 12; as vsoon :as .the -fusefmelts The. explosive :tendency .of the. melting fuse, supplementedby1the leader ejector 68, tends to break.

the rv:circuit'as quickly `as 4possible and to extine guishthe arc insidesthetube 1:2.

.The fuse tube-'unitl 12J having/been reefused, it

is then hung upon a disconnect stick by means of the 'ringrm inafposition. depending from the rin'g8'4, and then thev fuse tube unit may be' lifted by means of the stick until the-lip H2 passes over `the trunnion-s -63, as 'shown in- Figure 3, and the.` unit is hung on the trunnions r6? by means of the cylindrical-portions -i |10.' of theelaterally projecting flanges H l. i v

It'should be understood .that the .trunnions-.B3

project laterallyl fromeach parallel side, .wall-:54, 55, :butterminate with a. space between their endsy into'which-the ejector lever caribe inserted. The. laterally projecting. flanges. -Hi on thefejector lever project far enoughto .,extend over the y,in-v

wardly projecting trunnions carried-by the `.side walls 55, vso .thatvthe-.ejector lever serves at this time asa support -withwhich lto hang the fuse tube-.unit If2. on the lower `trunnions in its invertedposition.

- Thecperator then-removes hisidisconnect stickv from the .ring B4 and placesit .in the ring MI' which nowis lowermost. The-operatorithenvuses thevdisconnect .stick .to pivot `the vfuse tube unit L2 counterclockwise from .the-depending. position described, upward yon the trunnions .63 to vthe position of Figure 1.

As .the fusey tube unit i2 .passes fromI its upside down depending positionto .the kposition otliigurer l, `the laterally projectingiianges IH engage the, trunnionsSby means ontheirllatfsurfaces lili).v

As the fuse .tube unitmoves .upward counterclockwisegravity causes the fuse tube. unit .I2-to,

slide toward theleft, inEigure. 1, on trunnio-nsf. engaging. Ysurface 'm9, because the surface H19 slopesdownward .toward thelleft. 'Thsbrings the trunnions 6.3 into .engagement with contacts. IV M; .Asthe upper vcontactrixture,. lill .approaches .the contacts L55, 15.1, itisguidedlhetween. the con-v tactsby having its. -trunnions i24 guided. by the flaring surfaces` ldd, IAB until. the .trunnions are forcedbetweenthe .contactsprings |56. DuringA this .action .the upper contact xture .53 may pivot. on its bolt. lIZ'I under .the friction, imposedA by ,aspring lockwasheron this bolt, .the movement .being- `permitted `at the holt` 120 by the elongated .slot 1.23. 'Thus the. eiective distance between. `the upper andi Alower contact arms is automatically adjusted to the length of the, Vfuse tube unit, and, variations. in length of this unit will not, .affect .itsproper operation.

curved .contacts ljldengaging thetrunnions latgthe bottomhave enough curvature andeX- tend, peripherally .suflicient .to Voverhang the .back

ori'letsid'e ofthetrunnions'i slightly. Thus-the v lower end of the fuse tube unit I2 is retained on trunnions 6.3, carried by hoodAl. rIlhe upper end'iis retained by vcontact springs 15E-engaging trunnions 112# .on iuse tube unity 1.2. 'Theiuse tube .unitii's .now installed ,ready'to protect. the circuit. I

'Y :Op'cratz'unas ctiidisconncct I Tooperate Vthe cut-out asa disconnect, a dis@ connect'fstick may have' its Vend hooked in the ringflwl. If the operatorthen pulls onthe stick theftrunnions 1I-'M` "will 'cam' 'the contact springs 1.553 occurs the fusible portion of the fuse 98 is meltedtheelectricxcurrent and ruptured, producing an. explosive-:amount or `,gas .which 1 passes-out .of

thelower of .the .lower xture 15, expelling;

Y the cable leader 98 which is:.alsoV pulled-out byv 2m 4the fusefejector,I arm: 6:8.

direction by the .compression spring -81 acting,

on thefstruti, which. hasta Afor-.lied Vend :engagingl the4 Aejector-:lever 'i6-8;,pulling out the' -fuse leader 25: 98.

96, hammer flange l-Ifl. has its sharp-end-moved toward- `the -trunnions' 6-2', r63 -until this sharpend engages 4.between thetrunn-ions :in the fixed aovcontact H4 on each side of the-lowerlxture"HL This tendstoraise zthecontacts M4, .andthe entire .ruse-tuhe-.unit-lisiraised1suiiiciently rfor-.the

overhang; of thecontacts IM tofclear the .trun-f nions $2., 63,. and simultaneously the contacts'.

35.` lMhare.urgedoutwardly itowardvthe right away frornitheftrunnions 6.2f.63..

This releases Athe :lower end of the. fuse tubeu-ni-t I-.2 vfromthe contact supportingarm 46-and theifusettube unit i2. .swings .toward the .right at.

.40; `its. lower end in a counterclockwise position trom.

the;positicn.of; Figure. 1.to.v aposition-which corref SpOndstothat.ot..l'ig,ure2..

When` .the -fuse y.tube unitis .in .thisY .position itmisan indication that. the.circuithas Anot been 4,5 openedby .usingthadevice as. a. disconnect, but

' Uvit .hasbeen 4openedby the..blowing .of Aa. fuse.

Itwill thus. be -observed .that wehave. invented l aiused .dropfout..cuteoutin.which.the jet action of..the..expelled.gases will Atend .to push. the fuse 450 tube unit into engagement withits upper and its lo,wer contacts, .retarding .any tendencies, of the dex/ice 'to open .tooA quickly. 'The device will not open .untilthepower arcs,.are extinguished, be-v` causelit, is. only after thearc-.is extinguished that 55 thejjetaction ceases from pressingjthe fusejtube unit I'backwarjdly into engagement with its con@v tacts.

The present assembly has .the contacts so ar-A ranged that they are self-.algnnglto compensate .for discrepanciesin the length oli the fuse tube "units or inthe .spacing between the, contactsupporting. arms, which are due to the `varatirms in manufacture. Thejadvantages of ourimproved device Ymay be summarized' as follows: 65

links of. 'any .manufacturer .and Vto be handled' accordingto `conventional practice.

` V2. "Thellowcrcontactofthe fuse tube is ejected y from theibottom contact. arnr upon rupture ofthe j '7o fuse'linkl yso lthat the yfuse tube will Vhang 'with j its i opening 'extending downward `after operation, thus protecting; the interior of the fuse tube from all'adverse weatherconditions. j

3. 'The construction; of the mechanism vis such '7; that' the'inechanical 'opening 'of the lower cony A,'As.-=the-ejector flever f68 Erota-tes lupon its: vpivot t l. It is `adapted toA use standard universal rfuse' V 11 tacts is delayed until the arc has been definitely extinguished.

4. The jet action from the lower end of the tube tends to keep the upper end of the fuse tube in its proper position and to hold the lower end in position until after the blast, thus delaying mechanical opening until the arc has been extinguished.

5. The resilient spring contacts with their wide flaring ends are adapted to register with the trunnions of the fuse tube units, eventhough the dimensions may vary due to manufacturing tolerances and the contacts may give sufficiently to become self-aligning as they engage the trunnions.

6. Any undue strain on the spring contacts is prevented by the provision of stop surfaces which take the thrust that is caused by jet action during rupture of a fuse.

7. The present fuse unit may be operated as a disconnect switch, but when so operated its automatic mechanism is still trip-free, so that a fault on the line will open the lower contacts even while the operator is closing and holding the upper contacts. l

`8. The device gives a visual indication at all times whether it is actively in the circuit or whether the circuit has been broken purposefully at the top or automatically by rupture of a fuse at the bottom.

' While we have illustrated a preferred embodiment of our invention, many inodcations may be made without departing from the spirit of the invention, and we do not wish to be limited to the precise details of construction set forth, but desire to avail ourselves of all changes with in the scope of the appended claims. v

Having thus described our invention, what We claim as new and desire to secure by Letters Patent of the United States is:

' 1. In a fused drop-out cuteout, the combination of an insulating support with a pair of outwardly projecting contact supporting arms, and a housing member carried by each of said arms, said housing members being formed with top wall, rear wall and side walls and being forwardly and downwardly open, xed contacts carried by one of said housing members and resilient contacts carried by the other of said housing members, both of said contacts being arranged for rtatable engagement with trunnions, and a fusev tube unit comprising an insulating tube with contact xtures at each of its ends electrically` connected to each other by a fuse in said tube,

said contact fixtures being provided with laterally extending trunnions for rotatable engagement with the contacts carried by both of said housing members, the fuse tube being rotatable upon the gagement with the contacts carried by both of, said housing members, the fuse tube being rotatable upon the trunnions at either of its ends,` the said housing supporting said resilient contacts being formed with upper stop surfaces for engaging the upper and outer sides of the trunnions on the fuse tube unit to prevent the contact spring from being strained beyond the point of engagement of the trunnions with said stop surfaces. l

3. In a fused drop-out cut-out, the combination of an insulating support with a pair of out-`y wardly projecting contact supporting arms, andv a housing member carried by each of said arms, said housing members being formed with tcp wall, rear wall and side walls and being forwardly" and downwardly open, fixed contacts carried'lby one of said housing members and resilient contacts carried by the other of said housing members, both of said contacts being arranged for rotatable engagement with trunnions, and a fuse tube unit comprising an insulating tube with contact xtures at each of its end electrically connected to each other by a fuse in said tube, said contact fixtures being provided with laterally extending trunnions for rotatable engagement with the contacts carried by both of said housing members, the fuse tube being rotatable upon the' trunnions at either of its ends, the said spring contacts comprising a pair of electrically conductive leaf springs carried by the housing for engagement with each of the laterally projecting trunnions, and said leaf springs being formedr with partially cylindrical trunnion engaging sur v` faces.

4. In a fused drop-out cut-out, the combination of an insulating support with a pair of out, wardly projecting contact supporting arms, andy a housing member carried by each of said arms, said housing members being formed with topwall, rear wall and side walls and being for-v wardly and downwardly open, fixed contacts cart 4 ried by one of said housing members and resilient t contacts carried by the other of said housing members, both of said contacts being arranged for rotatable engagement with trunnions, and a'l fuse tube unit comprising an insulating tube with ,I contact fixtures at each of its ends electrically, connected to each other by a fuse in said tube, said contact fixtures being provided with laterally ij extending trunnions for rotatable engagement" with the contacts carried by both of said hous ing members, the fuse tube being rotatable upon the trunnions at either of its ends, the said spring contacts comprising a pair of electrically con ductive leaf springs carried by the housing for d engagement with each of the laterally projecting" trunnions, and said leaf springs being formed with partially cylindrical trunnion engaging surfaces, the said leaf springs being provided with forwardly extending flaring portions extending from said trunnion engaging portions to guide j the trunnions into position between the leaf l springs.

silient contacts carried by the other of said housing members, both of said contacts being ar# ranged for rotatable engagement with trunnions, and a fuse tube unit comprising an insulating tube with contact fixtures at each ci its ends electrically connected to each other by a fuse in saidl laterally extending trunnions for rotatable en- 5. In a fused drop-out cut-out, the combination of an insulating support with a pair of out-` wardly projecting contact supporting arms, and a housing member 'carried by each of said arms, 1 said housing members being formed with top wall, rear wall and side walls and being forwardly and downwardly open, xed contacts carried by one of said housing members and resilient contacts carried by the other of said housing members, `both of said contacts being arg-,1w ranged for rotatable engagement with trunnions,

guarisce-'f and: arfuses tube,A uniti' comprising: an insulatingsi tube with contact fixtures at.- eachzof its'v ends' electrically' connected. to each other by a: fuse in; said tube', said contact iixtures being-'provided with laterally extending trunnions .forf rotatable engagement with the; contacts?` carriedby both;

of* said' housings' members, the fuse; tube` being rotatable upon thentrunnions; at eitherof its' endstth'e saidsprin'g. contacts' comprising'a. pair.

or electrically conductive-leaf springs carried bye-f' the housing for engagement witheach of the" laterally projecting trunnions, and; said: leaf springs' being formed. with partially cylindrical t'ru'nnion'- engaging surfaces, thesaid: leaf springs: being: provided ontheirA outside with re-,enforceing` leaf' springs. for urging" the:y i'lrst-i-mentioned leai` springs into engagement with: the'trunnicns.:

' 6*.' In: av fused drop-out'cut-out; the:l combina-- tion'V oi".V an insulating" supportwith: ax; pair oi". outa-f wardlyh protecting contact` supporting'i arms; and

a housing member carried by each of' saidarrris, said; housing' members being formedV with top;

said tube. said contact i'lxturesbeing;provided4 with laterally extending trunnions for rotatablel engagementv with theA contacts carried by both of said? housing members. the fuse tube being roi-"- tatablef upon the trunnions at'eith'er of its: ends, thezsaid' spring, contacts comprising a pair of electrically' conductive. l'eaf springs carried by the ,housing for engagement' with. each of" the laterally projecting trunnions, and said leaf springs being formed with partially cylindrical trunnion engaging surfaces, the said housing supporting the leaf spring having its walls provided with stop surfaces for preventing the bending of the leaf springs in either direction beyond a predetermined point, and to absorb the' shock fromV the blowing of a fuse transmitted by the tube unit to the trunnions.

'7. In a fused drop-out cut-out, the combination of an insulating support with a pair of outwardly projecting contact supporting arms. and a housinggmember carried by each of said arms, said housing members being formed with top wall. rear wall and side walls and beingv forwardly and downwardly open, iixed contacts carried by one of said housing members and resilient contacts carried by the other of said housing members both of said contacts being arranged for rotatable engagement with trunnions, and a fuse tube unit comprising an insulating tube with contact fixtures at each of its ends electrically connected to each other by a fuse in said tube, said contact fixtures being provided with laterally extending trunnions for rotatable engagement with the contacts carried by both of said housing members, theiuse tube being rotatable upon the trunnions at either of its ends, the said spring contacts comprising a pair of electrically conductive leaf springs carried by the housing for engagement with each of the laterally projecting trunnions. and said leaf springs being formed with partially cylindrical trunnion engaging surfaces,r the said housing rsupporting the leaf springs having its walls provided with stop surfaces for preventing the bending of the` lea-'f springs in either' direction` beyond a predetermined point, andto absorb the:-

shock' from the blowing of an fuse.v transmitted by the tube uniti to theftrunnions', and the said latter: housing being provided"y with flaring guide' surfaces for" engaging thetrunnions' and guide ing them into engagement with the leaf spring contacts'.

8. In al fused drop-out cut-out, the combina'- tion oran insulating support. witha pairof outwardly projecting contact supporting arms; and:

a housing member' carried by each of saidarms,

said' housing members being formed. with topfwall, rear wall and side' walls and being' for wardly'and downwardly open, fixed contacts' car'- riedby one of'said' housing members and resilient contacts` carried by' the other of' said housing members;v both of said contactsv being arranged for rotatable" engagement: with trunnions, and a.

fuse tube'v unit"` comprisingl an insulating tube' with contact fixtures at each of its ends' elec trically connected to each other by a fuse insaidi tube, saidA contact` xtures being provided with` laterally extending trunnions for rotatable engagement' with the contacts carriedby' both of said housing members', the fuse tube being rotat-table' upon the trunnions-at' either of its ends, the said spring contacts comprising a pair of electrically conductive. leali` springs carried by" the housing for' engagement with each of 'the'v laterallyI projecting.' trunni'on's; and said leaf springs: being formed with partiallyA cylindrical tru-nnionv engaging' surfaces, one of said housing members being' fixedly secured to its contact"v lsupporting arm and the other of said housing members being xedly secured for a limited rotatiye movement on the contact supporting arm tuv permit adjustment of the' distance between tube unit.

9. In a fused drop-out cut-out, the combination of an insulating support with a pair of outwardly projecting contact supporting arms, and a housing member' carried by each of said arms, said housing members beingformed with top wall, rear wall and side walls and being forwardly and downwardly onen, iixed contacts carried by one of said housing members and resilient contacts carried by the other of said housing members. both of said contacts being arranged for rotatable engagement with trunnions, and a fuse tube unit comprising an insulating tube with contact iixtures at each of its ends electrically connected to each other by a fuse in said tube. said Acontact fixtures being provided with laterally extending trunnions for rotatable engagement with the contacts carried by both of said housing members, the fuse tube being rotatable upon the trunnions at either of its ends, the said spring contacts comprising a pair of electrically conductive leaf springs carried by the housing for engagement with each of the laterally projecting trunnions and said leaf springs being formed with partially cylindrical trunnion engaging surfaces, one oi" said housing members being xedly secured to its contact supporting arm and the other of said housing members being xedly secured for a limited rotative movement on the contact supporting arm to'permit adjustment of the distance between contacts to adiust itself to the length of the fuse tube unit, the movement of said latter housing being limited by a second securing bolt passing through the contact supporting arm and passing through an enlarged' aperture in the housing xture. 10. In a fused dropout cut-out, the combination of an insulating support with a pair of outwardly projecting contact supporting arms, and a housing member carried by each of said arms, said housing members being formed with top wall, rear wall and side walls and being for- Wardly and downwardly open, fixed contacts carried by one of said housing members and resilient contacts carried by the other of said housing members, both of said contacts being arranged for rotatable engagement with trunnions, and a fuse tube unit comprising an insulating tube with contact xtures at each of its ends electrically connected to each other `by av fuse in saidtube, said contact fixtures being provided with laterally extending trunnions for rotatable, engagement with the contacts carried 'by-both of' said housing members, the fuse tube being rotatable'upon the trunnions at either of its ends,U

the said spring contacts comprising a pair of electrically conductive leaf springs carried by the housing for engagement with each of the laternily projecting trunnions, and said leaf springsV being formed with partially cylindrical trunnion engaging surfaces, one of said housing members being xedly secured to its Contact supporting arm and the other of said housing members being fixedly secured for a limited rotative movement on the contact supporting arm to permit adiustment of the distance between contacts to adjust itself to the length of the fuse tube unit, the movement of said latter housing being` resisted by friction applied to its pivot by a resilient member compressed on the pivot bolt, and urging the housing member and contact arm into tight frictional engagement with eachother. v.

11. In a fused drop-out cut-out, the combination of an `insulating support withA a pair of;

outwardly projecting contact support arms, and a'housing member carried by each of said arms. saidVv housing members being formed with top 3 wf'all, rear wall and side walls and being forwardly' and downwardly open,v fixed contacts carried by one of said housing members and resilient contacts carried by the other of said housingl members, both of said contacts being arranged for rotatable engagement with trunnions, and:

a fuse tube unit comprising an insulating tube withv contact iixtures at each of its ends electrunnions at either of its ends, the lower of said fuse .ftube contact fixtures being provided withl a spring bias ejector arm, said ejector arm carrying striking anvils arranged to strike projec' tions adjacent the fixed contacts of the lowerhousing member to force the contact surfaces ofthe lower fuse tube fixture out of latching enf" gagement with the fixed contacts of the lower' housing member.

DAVID C. HUBBARD.

WILLIAM L. HOLLANDER..

REFERENCES CITED 'The following references are of record in the' rle of this patenti UNITED STATES PATENTS Number Name Date 1,787,291 Thumin Dec; 30, 1930 1,918,542 Heinrich July 18, 1933 2,212,633 Bodendieck Aug. 27, 1940 2,446,676

y Yonkers Aug. 10, 1948 i