US1738867A - Automatic fuse protector - Google Patents

Description

Dec. 10, '1929. J, C, CALL 1,738,867

AUTOMATIC FUSEl PROTECTOR Filed May l, 1.926 3 Sheets-Sheet 1 ?.r 5. Z

-1 ly Ff De. 10. 1929. y J. c.v CALL 1,738,867

AUTOMATIC 'FUSE PROTECTOR l AFiled May 1,1925 l' Smets-sheet 2.

Dec. 10, 1929. J, Q CALL AUTOMTC FUSE PROTECTOR Filed May 1, 192e 5 Sheets-Sheet 3 QN Wm Patented Dec. 10, 1929 JOSEPH C. CALL, OF BANCROFT, IDAHO AUTOMATIC FUSE PRoTEo'roR Application led May 1, 1926. Serial No, 106,057.

This inventionvrelates to an automatic fuse protector and .its principal objects are:r

First. To perform the functions of a cir cuit breaker by protecting an electric circuit 5 against damage from overloads or shorts.,

Second.` To provide the equivalent o-a perpetual'fuse thus avoiding-'the continued 1expense' of'buying new fuses. Third. To-save vtime and lannoyance lby indicating at a glance, any particular fuse `element of a plurality that may have blownl 1 Fourth. To provide the convenience of replacingvwhat amounts 4 to a burned out fuse,V

In attaining the objectsl just outlined, I provide a main switch, an auxiliary switch, an electro-thermic element and a fuse ele, ment.- all'in' circuit, electrically, with each other. 55 The main switch is controlled by the electro-thermic element, the latter being adjusted to cause it to open, preferably by means of a snap mechanism, when more than a predetermined vamount of current passes 50 by simply a slight movement of a rotatableIv sleeve.

Fifth. To furnish in one convenient structure the combined advantages of a fuse and a circuitfbreaker.

Sixth. To provide, it desired, a fuse as an integral part of the circuit-breaker.K Seventh. To be so arranged that it may be through the circuit, -this amount being less,

of course, than is required to blow the fuse element.

By again closing, or re-settmggthe mam switch after each release, the fuse may be madlesto serve indefinitely. 'Beforethe resettling Acan take place however7- the circuit must" be 'opened' at another `point or points,

and remain open during the re-setting of self-contained in substantially the limited space of an ordinary fuse plug, adapting it 25 without alterations to either one. This gives small `electrical equipment,such as ,house lighting circuits, the sameI .circuit-breaker protection that is usually given only to cir- 39 cuits. of larger capacity;

Eighth. To operate in any position. l' Ninth. Tobe proof against having any of its parts displacedv by jarring.`

the main switch to guard against dead shorts 7o on the line. Shortly thereafter, the auxiliary switch is ,again closed', which restores the operative' V capacity of the device. The

'proper sequence in the movements of4 the 'to standard fuse blocks and .metal'cabinets re-setti'ng Tenth. To be controlled electro=thermally instead 'of- 'electro-magnetically, thereby eliminating any hum ornoise when operating on an A. C. line. l

Eleventh. To protect a m'otor circuit against damage from a dead short on the line while providing the time .element for allowinga momentary over-load when the motors are starting. Ordinarily, circuit-,breakers designed for motor circuits, will not prevent the fuse from blowing when there is a dead short on the line. and conversely, when designed to take lcare ot' a dead short, will not remain closed when motors are starting. i Twelfth. To make it `impossible to damage the device or the line, shouldthe former be closed with a short on the line.

`cessed and channeled'to receive them.

.auXiliary'switc-h fandthefmain'switch dur- 75 ing-this restoration, isnaccomp'lished by the mechanism, which may consist of suitably relatedcams. y

The fuse element may be directly associatedwith the'other parts in a self-com 80 tainedstructure, or not, as desired.

` In Athe plug type of this device, designed to tit anyordinary fuse block, the self-contained operating parts are supported by a -cylindrical body structure made of insulating material such as porcelain, properly re- The body structure is enclosed by a shell, torming a casing or housing which is rotatable in relation thereto.

The main switch is released by the lengthening of a heated wire when an excessive vcurrent is passing through the circuit, this rel-ease being edected with a sharp snap, leaving the contents widely separated, and preventing any possibility of sustained arcing. The releasing mechanism is so'arranged that no stress is lplaced upon the highly heated wire after the moment otrelease. 100

been ,re-set, a slight further rotation of the The lie-setting of the device is accomlished by means of the rotatable shell', the atter having internal cams for engaging .both. sets' of switch members. vBefore the main switch contacts are brought to a bear-v ing `upon each other, the auxiliary switch members are opened, so thatthe closing of the-main switch is effected. with no current passing -through it, thus .establishing the certainty that the main contacts can never be held in the closed position by the re-setting mechanism, even momentarily, should there' be a dead short on the line while the re-setting operation takes place.

As soon as the main switch contacts have shell again causes the auxiliary switch to be closed, preferably with a snap, thus re-establishing the circuit. j

A movable button in engagement with the main switch, protrudes from the outside of the shell and serves to indicate whether or not the switches are in the normal position.

The features of this invention for which the protection of LettersPatent is desired, are collectively grouped in the claims which conclude this specification.

In the drawings, which illustrate merely one desirable form of this invention:

Fig. 1 represents an elevation with the shell and the resetting cams omitted, looking in the direction of the arrow 1 in Fig. 3;

y Fig. 2, a similar elevation diametrically opposed to the elevation in Fig. 1, but reflectedv from a mirror plane ;v

Fig. 3, a top' plan, the upper part of the casing'having been removed, leaving the side wallspin section on line 3 in Fig. G

Fig. 4, horizontal sections in different planes on line 4 in Figs. 7 and 9, reflected from a mirror plane;

Fig. 5, horizontal section on line 5, 8. some parts in plan Fig. 6, a vertical section on line 6, Fig. 3, parts in the foreground in elevation, with main` switch contacts closed; 1 I

Fig. 7, same as Fig. 6', but with main switchv contacts open; l

Fig. 8, a vertical section on line 8, Figs. l and 5, fragmentary parts in the foreground being in elevation, and other parts being broken away;

Fig. 9, a` vertical section, principally on line 9 in Fig. 3, with minor sections in different planes taken substantially along line 91 in Fig. 3, various parts being-.broken away for convenience, and other parts in the foreground shown in elevation;

Fig. 10, a panoramic development of the ele-N vation around the body, beginning at 10, Fig. 3, and proceeding in the direction of the coiresponding arrow; the housing shell being removed, but the re-setting cams left in place.

This figure is somewhat diagrammatic in form.

incase? vgroove joint 2521 preventing axial shifting.

The parts just mentioned may be made of any material having suitable insulating properties, such as porcelain, the separation of the 'parts from each other, being for convenience in manufacturing and assembling.

The lower portion ofthe plug 20 may be threaded and enclosed by the'usual conductor shell 26, the latter being flanged along itsl lower edge to hold the insulating piece27 in place.

The body portions 21 and 211 are surrounded bythe concentric composite cam sleeve composed of the sections 28 and 281 made of insulating material and of sections 29 and 291 made of electrically conductive material, such as metal, preferably iron, these sleeve sections .being interloclred with each other, as shown in Fig. 10. The cam sleeve sections are tightly pressed into the housing shell 30,

which may be made of metal such as brass, lined with insulating paper 31. The bottom of the operating sleeve may be crimped over to forni the iiange 301 which serves to hold the base 2() in place. serted cam sleeve is substantially concentric with and rotatable relatively to, the body parts of the structure.

Within the bore 32 of the base 2O is the hollow stein 34, which at its upper end carries the crosshead 35 terminating in the contacts 3G and 361, the crosshead being insulated from the stem by the bushing The stem 3d is movable up and down and is loosely held in alignment with the bore by means of the rThe shell 3() with its inenlargement 37. The bore ofthe stem 311 j.y;,

` ai iaiiged to re-act against the head 391 of the pin, which in turn is seated in, and presses upwardly against, the button structure 40, which latter is shouldered to form the neck 401 andtliesubstantially square flange 402 (Fig. 3)

Oscillating contacts 41 and 411 of the main switch are pivoted at 42 and are provided with the rearwardly exten-ding lever arms 43mm/- ably engaging the button structure 40, and riding on opposite edges of the v square iange 402.

The erosshead contacts 36 and 361, and the oscilla-ting contacts 41 and 411 constitute the main switch of the device, open in Fig. 7 and closed in Fig. 6. It will be observed that in closing the main switch, the extremities of the respective contacts will be first to come -into bearing- With each other, and as the crosshead is pushed home to the closed position, the

contacting surfaces will'have a mixed sliding and rolling or wiping action against each.

other. Thus, the final bearing surfaces at 44 will always be in condition to make an excellent electrical contact.

Near its lower end, Athe stem 34 has the collar 60 shaped as the frustum of a cone and arranged to be engaged by the slidable latch -61 (Figs. 5, 6 aiidS). The compression andin the slots 71 of the slide, (Figs. 5 and;

springs 46, operativein recesses 7 0 ofthe body 8.) 'bear againstthe stationary faces 72, and

tend to withdraw the latch from engagement with the collar 60. Normally, this is pre-. vented by the adjustable screw 47 threaded in the opposite end of the slide and bearing the wi-re48, the same is correspondingly overheated and thereby excessively lengthened, allowing springs 46 to draw the latch outof engagement with collar ,60, the stress on the hot wire being relieved almost instantlyf however, by reason of the contactof faces 81 of the latch, with springs 46. This travel of the' latch causes the stem 34 with its crosshead 35 to be snapped down by the spring 38,'the latter exerting its force against the bottom of enlargement 37, and re-a-cting against the 'button structure 40, pushing the button upwardly to the position shown in Fig. 7. This ligure shows the widely separated positions of the reciprocating contacts 36 land 361 from the structure.

oscillating contacts 41 and 411 respectively, when the main switch is open.

The auxiliary switch consists of the arms 49 and 491, having the integral sleeve por' tions 62 and 621 respectively, within which are4 the coiled springs 50, whosev ends 501 are held in the slots 52 formed in the body The other ends 502 of the coiled springs'b'ear against the pins 51 fastened in the arms 49 and 491, urging these latter down-` ward'ly. The full lines in Figs. 1 and 2 show arms 49 and 491 in the normal or closed position 'of the auxiliary switch. These arms have an-oseillating .mot-ion about the axes of sleeves 62 and 4621 respectively, these latter being rotatively disposed in recesses in the body structure. The arm 49 is electricall connected bymeans of the pig-tail 53 to the main `switch contact 41, while the other arm 491-is electricallyl connected by means of the.

pig-tail 54 to' the leg 481 of the -wire 48. The functioning of the auxiliary switch arms 49 and 491 will presently be made clear.

Electrical circuit The electrical circuit through vthel device,

assuming the various parts`-t"o be in the conductive or operative position, will vnow be described in detail. The circuit may be best followed `by lreferring principally to Fig. 10.

The-.current from one leg ofthe line (not indicated) enters the bushing 56,- passes through the'integral brush 57, through the cam sleeve conductor 291, through the auxiliary switch conductor arm 491, through pig-tail 54, then consecutively through'the legs 481, 481, 483 and 48l1 of the thermic control wire 48, through pig-tail.58, through the main' switch oscillating contact 411, through the crosshead contact 361, through crosshead 35, through crosshead'contact 36, through main switch oscillating contact-41, through pig-tail 53, through auxiliary switch conductor. arm 49, through cam sleeve conductor 29,

through brush. 59, and out through the me-` tallic shell 26intol the return leg of the line.

Supposing the various parts of the device vto be in the set or normal working position, with current flowing through the circuit just described, then an excessive'inlux would overf I.

heat the wire 48, allowing the springs 46 to vdraw the slide 61 in the direction of the arrow 80 in Fig. 5, therebyl releasing the stem l34 and causing the main switch to snap open through theaction of spring 38, in the manner 'already described, thus preventing any in ]ur'y, by the over-load, to this device or to the circuit which 'it protects.

In order to re-set the device, the shell is rotated in the direction of .the arrow 62 in Figs, 3 and 10, thevirst result of this action being to cause the conductors 29 and 291 to pass under the lugs 63 of the auxiliary switch arms 49 and 491-respectively,'until the said lugs have become disengaged by dropping over the upper corners of the 'cani portions 64 and 641, thereby allowing the arms 49 and 491 to be forced by springs 50, into the lower positions indicated b v dotted lilies in Figs. 1, 2 and 10, thus leaving the auxiliary switch open.

The further rotation of the shellwith its re-setting cams, will-cause the cam portions 65 and 64 to engage the inclined face 671 of the crosshead contact 361, and simultaneously will cause the cam portions 651 and 641 to engage theinclined face 67 of the crosshead contact 36, thereby raising the crosshead 35 with its stem 34, again compressing the spring' 38, and finally, causing the cone face of collar 60 to engage a portion of the surface dey lining the invertedcountersunk opening in the slide 61, forcing the same against the tension of wire v48 until-the bottom surface of collar 60 rises above the upper surfaceof slide 61` at which moment the tension of the wire 48, exerted through vthe toggle action of the two branches of leg 481, against the I .screw 47, caiises the slide 61 to slip back der the cpllar() to the position shown in Figs. G and 8,-threby again compressihg the light springs 46 and leaving the mainjswitch again' in the operative'posltion., Y

i hleanwhile, the cam 651 will have'advancedl under the lug 63 of auxiliary switch arni'49,

and cam will'have advanced under lug 63 ot auxiliary switch arm 491, and asa these are made of insulating material, no current will pass, thus permitting the-safe re-setting,

of the main switch parts, as previously described. A little further rotation of the shell brings the uppercorners 'of the lcams 64 and 641 somewhat beyond the crosshead contact members, and when the position shown in Fig.

. l() has been reached, the lugs 63 of the auX- iliary switch arms 49 and 491 respectively, will have slipped over the upper corners of y the cams 6 51 and G5. and come to rest ino the notches GS, as shown in Fig. 10, thus completing the re-setting et' the device.

Each complete half turn of the sleeve with its re-setting cams completes a re-setting cycle. and each set oi" cams 65 and 64, and 651,

and 641 will`operate alternately -upon the mainiswit'ch contacts and the auxiliary switch contacts in an endless series of re-setting cycles.' l Y `Itwill be notedv that the turning ot the re-setting cams in the wrong direction to anyv considerable .extent, is prevented by the ratchet tooth action of the vertical, faces just below the upper corners of the cams 64 and 65, and 641 and 651 against the auxiliary switch arm ings 63,.y

The pig- tails 53 and 54 may 'constitute the fuse element where fit is desired .to have the fuse within the structure of the device, otherwise vthe fuse may be located at a point remote therefrom.,- I

`lovel` features possessed by the `present invention, :besides those already emphasized, include:

(a) Heavy main switch contacts "with a long quick break between themI` 'forming substantia-,lly al circuit-breaker.

(b) Main switch'andl auxiliary switch each arranged t'o nbreak at Atwo points, thereby doubling the length of the gaps that would otherwise be available.

c) ,One spring serving to separate the main spring contacts when these are opened, and also to' hold the contacts iirmly together when. the circuit is closed. 1 y

'((Z) vThe pressure on both mainl switch contactsalways equalized regardless of wear resulting `romlong use.

(c) l-hebacleand forth or' looped disposal of 'the electro-thermal control, making it possible to use a wire ot comparatively long stricted fuse plug dimensions.

(f) Toggle arrangement of control wire to length within the limited space of the re'- masser obtain sui'cient translated motion to trip lock releasing main switch members.

ile a typical embodiment'of this invention isherein-shown and described, it should be clearly understood thatJ all the detailed parts thereof, may or may not, appear in the preferred forms, and also, that the preferred t'orms may bevaried from time Vto time, depending upon the circumstances land conditioiis governing and governed by, the development of this invention and the arts to which it is incident, therefore its scope is .broadly stated in the claims.

= Having fully described my invention, what -in cycles, each cycle embracingat predetermined interyals (a) opening auxiliary switch; (ZA-closing main switch, (c) closing auxiliary switch.

3. A self-contained fuse protector comprising in combination, a main switch, an auxiliary switch, -a thermal control having a wire, a co-acting slide extending transversely of the said wire, the slide being arranged to trip said main switch under predetermined, conditions and a re-setting mechanism operative upon said switches in predetermined mutual relation Yto each other.

4. A self-contained fuse protector comprising in combination, a main switch, an auxiliary switch, a thermal control having a wire, a co-acting slide extending transversely of the said wire, the slide being arranged to trip said main switch under predetermined conditions; and a re-setting mechanism operative in cycles, each cycle embracing at predetermined intervals,l (a) opening auxiliary switch, (Z1) closing main switch, (c) closing auxiliary switch.

Aself-contained fuse protector comprising in combination, a plurality of reciprocative, non-oscillating, snap-release contacts ar- Y ranged for engagement with a plurality of oscillating stationary contacts constituting a main switch, spring pressed oscillating arms constituting'an auxiliary switch; a thermally actuated releasing mechanism for said main switch, all in circuit with each other; and a rte-setting" mechanism operative upon said switches in predetermined mutual relation to each other.

lOO

CTI

oconstituting an auxiliary switch; a thermally actuated releasing mechanism` for said main.'

switch, alll in circuit with each other; and a" resetting mechanism operative in cycles, each' cycle embracing at predetermined intervals, (a) `opening' auxiliaryf'switch, (b) closing main switch?, (c) clos' ing auxiliary switch. 7 A seltcontained fuse protector compris.

ing-'in combinationgfalfpluralityfof reciprocativ'e, non-oscillating`3 snap-releasecontacts arranged fior engagementwith alpluralityot A oscillating: stationary' contacts constituting a :inai'n switch, spring pressed oscillating arms f .f con 'stitutingv an auxiliary switch; althermal" 'control' l'iavingav wire and Yy eoactin'glslide arj ranged totripsaid main switch under predetermined' conditions, and afjresettingmecha `nisiii` `operative 1n`-. cy cles, each. cycle embrace ing atpredeterminedinteryalsple), opening auxiliar fswitch', (b) closing-main switch,

ing ii'icrtibination", a 'plural ityof reciproca? tive, none-oscillating',.siiapfreleasacontacts ar- 'j r'anged for engage'mentA with a 'plurality ot oscillating stationaryfcontacts constituting a 4I main switch ,-spring pressed oscillating-arms constituting an ai'ixilia'ry"v switch`;- a ermal control having '.a-"wiref and a co-acting slidearranged to )trip said main 'switch under'pre determined oonditionsnd aresetting niech-v anism'operative' upon said switchesin predeltermined' mutuaLrelatiomto each-other.

' releasing mechanism for said main switch, all in circuit with each other; and a re-setting rotatablesleeve having cams operative upon said switches in predetermined mutual re.

lation to e'ach'other.v

10.A self-contained fuse protector comprising in combination, a main @na an`auxiliary snap switch, t ermally actuated releasing mechanismA for said mainf switch, all-in circuit with each other.;'and rein cycles,

'auxiliary switch.

setting rotatable sleeve having cams operative 1each cycle'embracin'g at predeter- `mined. j intervals,

switch, (blclosingmainswitch, (c) closing 1'1. A self-.contained fuse protector con Apri'sing in combination element, a main lsnap `prising in combination,

9. A selt-contaiiiedgfnse protector comprising in combination; a inain snap switch, an auxiliary snap switch;la,thermally actuated switch,

(a) opening auxiliaryv operative upon said switches in predetermined mutual relation to each other.' n

l2. Av self-contained vinse protector coma J'main snap switch, an auxiliary switch, a thermal control e'lenie1it,ra slide normally stressed against said control element, said slide arranged to-trip l.said main switch when the control element is excessively heated, 'means for relieving slide stress; from said control element when ex-- cessively heated; and` a 're-setting mechanism operative in cycles, eachcycle embracing at `predetermined intervals, v(a) opening auxiliary. switch, (Zi) closing -main switch, closingauxiliaryswitch.y

1B. A. self-contained fuse protector coniprisingciin" combinatioma mainsnap switch, spring pressed oscillating arms constituting.

an'auxiliary switch, atliermally actuated releasingmeclianism for said main' switch, .all

in-circuit with 'each other.; aiid a, re-settingl Vmechanism consistingota rotatable sleeve "having lcams operative upon-said switches 'in predetermined mutual relation to l.each

y .e g .Y 14. self-,containedfusefprotector com- 8;' "A self-ontainedfuse protector compris# an auxiliary switch, athermally actuated rel cessively heated; and a refsetting mechanism leasing Ainechanis'm for saidA main switch, all A in circuit 'with each 'othergand a re-setting y mechanism consisting of a rotatable sleeve .havingQcams' 'operativein cycles, each cycle embracingat predetermined intervals (a) A opening auxiliaryjsw-itch, closing main switch, .'(c) closingauxiliary switch,

lai-A' self-containedfuse protector com` prising incombination, a main snap switch, 'sprin'g pressed .oscillating arms constituting 4an auxiliary switch, a thermal control having v a'wire andco-acting slide arrangedto trip said main' switch under predetermined conditions; and a re-setting mechanism consistingaof a rotatable sleeve .having camsv operativeupon said switches in predetermined mutualrelation to each other.

prising in'comhination, a main snap switch, spring pressed oscillating arms constituting an auxiliary switch, a thermal control having a wire and co-acting slide arranged to trip ditions; and a re-setting mechanism consisting of arctatable sleeve having cams operative in cycles, each cycle embracing' at pre- 16. yA vself-contained fuse protector com- 115- vsaid main switch under predetermined conthermic control co-operatively disposedthere-f in; and a rotatable sleeve enclosing said fuse l a rotatable sleeve having means for re-setting.

plug, said sleeve having re-setting cams operative upon said switches.

18.-:[n combination, a. body of I'use plug type, a circuit breaker and an auxiliary snap switch co-operatively disposed therein; and

said snap switch; p

19. In combination, a circuit breaker, a

. I snap switch in circuit therewith, and a rotatable sleeve having cams operative on said snap switch; said snap switch arranged to be opened while the circuit'breaker is being closed, and closed after circuit breaker is again in position 'for automatic release.

22. In Va useprotecto'rpthe ,combinationwith oscillating contacts comprising non-flexingpivoted members, vof reciprocating contacts arranged in cto-operative relation thereto, means for normally `holding* the said reciprocating contacts in bearing with said oscillating contacts, an inechaiiisniairanged to release said holding means, and a' rotatable sleeve having means for returning said reciprocating contacts to said normal bearing.

23. A circuit-breaker havingean electrothermal control, an auxiliary snap switch normally in circuit with said circuit-breaker, and a rotatable'sleeve having resetting means operative upon said circuit-'breaker and upon -said auxiliary switch in a predetermined SeqllellCQ.

24g, In a fuse protector', a switch with velectro-thermal control comprising a spring lock engaging said switch, and a looped wire having toggle branches extending longitudinally of the body of said protector, said wire when excessively to disengage said lock..

25. A fuse protector comprising a body ofI fuse plug type, and a circuitbreaker with electro-tliermal control operatively disposed in said body, said control consisting oit a lock forsaid.circuit-bieakei, a looped wire having toggle branches extending longitudinally oi:

.the body of said protector, said wire when excessively heated being operative `to release said lock', and means for tensioning said wire.-

- 26. A fuse protectorA comprising a circuitbreaker with electro-thermal control, a locking member tensioned against said control at low temperatures and means for relieving electro-thermalv heated being operative predetermined higher temor said circuitbreaker, a looped wire having toggle branches, engaging said lock, and means for relieving said tension at predetermined higher temperatures.

28., A fuse protector comprising a body of fuse plug type and a circuit-breaker with electro-thermal control operatively disposed in said body, said controlconsisting of a slidable latch operatively engaging said switch, a heatable wire engaging said latch, meansl for normally 4tensioning the latch against said wire, and means for relieving said tension at comparatively high temperatures. I 29. In a fuse protector, a switch with electro-thermal control comprising a spring lock engaging .said switch, a 'heatable looped wire having toggle branches normally tensioned lby said lock, and means for 'relieving said tension when said wire reaches substantially a predetermined temperature.

30. ln a fuse protector, a switch having a springpressed reciprocative contact member, an electrically heatable wire extending longitudinally of the body of said protector Ain circuit with said switch,` a spring-pressed latch normally holding said contact member in the closedposition and simultaneously tensioning the said wire, said latch arranged to release the contact member when said wire elongates, means for relieving the tension upon said wire when the latter is excessively heated, and a. re-setting mechanism arranged to return said contact member to its closed-position. i

In testimonywhereofl sign my name hereto.

JOSEPH C. CALL.

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