US2662952A - Circuit interrupting fuse - Google Patents

Description

Dec. 15, 1953 J. Nlvolx CIRCUIT INTERRUPTING FUSE Filed Sept. l0

Hit-o rhe 15.

Patented Dec. 15, 1953 CIRCUIT INTERRUPTING FUSE Jean Nivoix, La Plaine Saint-Denis, France, as-

signor to Societe Anonyme Ateliers de Constructions dite: Forges et Electriques de Jeumont, Paris, France, a corporation of France Application September 10, 1951, Serial No. 245,805

Claims priority, application France September 22, 1950 Claims. (Cl. 200-120) The present invention relates to circuit interrupting fuses. These fuses may be of the socalled cartridge type and may comprise one or more fusible elements which may or may not be associated with quenching or arc-extinguishing material. More particularly, the invention has especial relation to circuit interrupting fuses of the renewable element type.

A primary object of the present invention is to facilitate the extinguishment of the arc which accompanies circuit interruption. A further ob- `iect of the invention is to prevent deterioration of the fixed contacts to which the renewable fusible elements are attached.

In conventional fuses of the type here involved, the fusible elements (rods, strips, wires, etc.) are xed between securing members of any suitable type or are otherwise attached to these member and the latter-which may also be designated fixed contactsare covered and protected from the arc generated upon circuit interruption by fusion of the fusible element, by means of one or more incombustible and insulating liners or washers of mica, asbestos or the like, through which each fusible element passes.

In such conventional arrangement, when the short circuiting current is high, the fusible element is completely volatilized and the arc extends to the fixed contacts, notwithstanding the aforementioned liners or washers. This is bound up with a number of defects: on the one hand, the fixed contacts are seriously damaged and fren quently are incapable of further use; on the other hand, the arc may even penetrate through the said members to the exterior, which is very dangerous; finally, even if the last-mentioned eventuality does not occur, the partial volatilization of the securing members or xed contacts generates an excessive amount of metal vapor which markedly lowers the circuit breaking capacity of the fuse and produces a risk of explosion.

The present invention provides simple and eflicient means for obviating these defects and for obtaining the afore-enumerated objects. In accordance with the invention, briefly stated, the fusible elements (rods, strips, wires, bars, etc.) comprise bends arranged so that the arcs which are propagated along such elements encounter a transverse insulating partition or partitions at a point suiciently distant from the openings through which undesirable propagation can take place, so that excessive elongation of the arcs is prevented.

With the above and other objects in view, which will become apparent from the detailed description which follows, reference is made to the accompanying sheet of drawings wherein several presently preferred embodiments of the invention are diagrammatically illustrated. Conventional cartridge fuse structure has, for the sake of clearness, not been shown. On the said sheet:

Fig. 1 is a diagrammatical view, partly in section and partly in elevation of one embodiment of the invention;

Fig. 2 is a similar view of a second embodiment of the invention; and

Fig. 3 is a similar view of still another embodiment of the invention.

Referring rst to the embodiment according to Fig. l, reference character F1 designates a fusible element, which may take the form of a strip or of a wire or the like of fusible metal or alloy (e. g. silver, etc.). Element F1 is secured in any suitable and per se conventional manner to securing members or fixed contact pieces A, B and A1, B1. A liner, bale plate or washer R lines the inner surface of contact pieces A, B and a similar member R1 lines the inner surface of contact pieces A1, B1, the members R and R1 being perforated so that element F1 may pass therethrough. Members R and R1 are advantageously made of incombustible or refractory insulating material such as mica, asbestos and the like.

Arc-stopping bafde plates or Washers R and R1 are provided according to the invention to prevent an arc, generated upon the fusion of element F1 at a hot intermediate point thereof from penetrating through to the perforation in liner R or R1. For mounting the members R' and R1, fusible element F1 is provided adjacent each end with a pair of spaced bends :c and y, each said pair of bends being connected by a short rectilinear portion extending substantially at right angles to the free portions of element F1 (which are shown as substantially rectilinear). Each auxiliary Washer R. and R1 is so disposed on element F1 that a lateral surface of the Washer is in contact with the adjacent short rectilinear portion extending between the adjacent bends .r and y. As shown in Fig. 1, the Washers R and R1 are perforated eccentrically (i. e. are offset relative to the perforations in main washers R and R to the extent of the said short rectilinear portion).

With this relationship of parts, any arc which is engendered due to the rupture of a free portion of the fusible element is eifectively stopped .sisting of a plurality (shown on the drawing,

at the washers R' and R'1 and is thus prevented from extending beyond the ends of the said free portion jof the sai'djelement. `At worstj-'f the interrupted current happens to be 'very strong-e the resultant arc may possibly partially volatilize the two portions of the fusible element which are disposed between the pairs ofrwashers R, Etf and R1, R1. In this way, the xed lrconta'c'is AyB and A1, B1 are eifectively and reliably protected from deleterious effects of the are. Y

If the circuit interrupting fuse is of 'the type requiring one or more intermediate partitions R2 (which may be of the same refractory material as the previously mentioned waslier's)`as where it is desirable for any reason to divide up the interior of the fuse into smaller spaces-such intermediate partition or partitions maybe retained in position with the aid of ji'ita'psed intermediate folds l?, P fbrmed in element F1, as lshown in Fig. 1 of the drawings. Y Y

n; certain eases, it is possible within the scopo 'of the present invention to I'dispense with 'the washers R an'd-R1. relationship of parts aecor'ding to this invention wherein the latter are Vomitted is ,shown in Fig. y2. This relationship of parts involves 'an intermediate partition R2, of the 'character described in the preceding paragraph. instead of disposing the said vinterinodi-- ate partition between "two intermediate folds P, P in the element F2, -it is disposed between one such fold P which contacts the `partition R2 -on one side thereof vand an intermediate short "rectilinear portion F of feleine'nt'Fz on the 'other side thereof. vPortion disposed essentially at a right angle to the v"free port-ions of element F2 and extendsv 'in contact the adjacent lateral v"surface 7 of part-iden Bonds and y are formed adjacent :each 'end bf the fusible 'element Fc, 'asinfthe bodim'ent-ac'cording to Fig. 1, fand the resultingshort rectilinear portions li An close r contac tfon"one side thereof withthe adj aeents'u'rface "of 'the ju'itaposed washer R or R1, `as shown v ion, an arc engendered on 'one 'sfido ioi the p iii-ion lai is effectively piovented `imm oi'aoifoing over to fono other sic-o 'of the partition. 'hefsnall rectilinear V"p'crtiorifs b'etween 'bonos c and y also minimize elongation of the are to 'and through -the perforations 'of the "washers R Iand R1. y n

Where ver? strong ir'iients y'are iikely to be encountered, propaga ion lof 'the 'arc is deterred according totnoirfvohtion 'Joy expedient which, -oo nary "o that of v-Eig. 2, involves increasing one number for protective and intermediate partitions. Such a relationship of parts is shown innig. 'a osoooieiiig to which roooh 'of uio ooveroi bends formed 'in the fusible element F3 (which may, in 'this embodiment, take the form of Va strip) yis completely enclosed ina structure coli;-

y way of example, as three)u of --spaed grou-ps of Washers R3, Rg or R5 which,like Vthe previously described Washers, 'are made of suitable relfractory material, such as nic'a, asbestosl orrthe iiiio. *rooie 'multiplo washers ibo' ijstoifijoc in assofii'oied groups by any suitable means, for 'ii'aiiipi 'with tifad'f "a 'suitabre cement or the like, augmented if de'sifeobyyori'o "or more additionalifordsrgassiiownin Eiga.A H

While the portions 'f the fusible elements which are not paroi-lei ojo the general airis tuera of, have been shown asbeing essentially "at right angles thereto, it will 'be "understood lthat such portions may extend at various angles. It will '4 also be understood that Various other minor changes may be made without departing from the spirit and scope of the invention.

Y Having thus disclosed the invention, what is claimed is:

`1. A circuit-interrupting fuse having terminal contacts, a fusible element with free portions extending between said contacts, insulating refractory'plates ,dis-posed between said contacts and provided with perffer'ations through which said elementl passes, said portions being laterally offset from sai'd perforations, said element being provideduwith a plurality of spaced bends defining `re`ctilir`iea p'rtibns therebetween arranged at an angle 'relative to said free portions, and Veac'l-i of said rectilinear portions being in contact with a lateral surface of one of said refractory places, whereby the points Where an arc, engendered upon fusion of said free portions, rnay reaeh said jrf-r'aot'or-'y plates are spaced frm the perfor'ations in said plates.

A2. A oircui'teinterrupting fuse having terminal contacts, a fusible element with free portions 'eX tending between said contacts, an insulating refractory :liner for each 'of said contacts and p'ro vided with a perforation through which sai-d ele# ment passes, an insulating refractory plate 'adjacent each liner and provided with 'a perforation through which -`said element passes, the pere forations of 'the liners Ibeing laterally offset with respect to the -perforations of the plates, 'said por'- tions being ycorresponuii-l'igly laterally loffset with respect to vsaid perfoifations of said plates, 'said element being provided with a plurality of pairs of spaced bonds adjacent, each can defining fa reco linear portion therebetween larra'mged at 1an angle relative to said 'free portions, arid eaoh of said rectilinear portions being in contact on one side with the lateral surface of one of said refiaetoliy liners and on the other side with one of said re'- vfractory plates, whereby the points wlieie an are, engendered upon fusion of said free portions, rnay reach said refractory A'plates are 'spaced from the perforations in said plates.

3. A circuiteinterrupting fuse according to claim 2, comprising o, further refractory plato te;

A circuit-interrupting fuse ac'sordinar to. "claim Y1, :comprising an 'additional refractory par'-v titfion located betweentheends of the fusible `ele"-V passage,

pieno and having a perforation fo-ioie ofV said eleinent, said perforation being laterally offset with iosfpooofoo uio perforaiions 'of said. plates, said partitionfbeirfg in Contact, along at afrooos 'cites in 'the fue of this paiera Unir-'ED STATES PATENTS Number Y Name Date 441,933 carini/right l Deo. 2, T1890y 1,237,462 sohwoitior e ai. 1L- Dec flo, 191s 2,443,017 Arorie et al. June 8, 1'943 FOREIGN PATENTS Number Country ADate A 494,132 Germany Mar. 19, 193'()y

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