US1109733A

US1109733A - Fuse-holder.

Info

Publication number: US1109733A
Application number: US76411313A
Authority: US
Inventors: Harry W Young
Original assignee: Individual
Current assignee: Individual
Priority date: 1913-04-28
Filing date: 1913-04-28
Publication date: 1914-09-08
Anticipated expiration: 1931-09-08

Description

H. W. YOUNG.

FUSE HOLDER. APPLIGATION FILED 93.23.1913.

Patented Sept. 8, 1914.

2 SHEETS-SHEET 1.

H. W. YOUNG.

FUSE HOLDER. APPLICATION FILED APR.28,1913.

Patented Sept. 8, 1914.

HARRY W. YOUNG, 0F CHICAGO, ILLINOIS.

FUSE-HOLDER. I

spemcation L emriracent. Application med A prn 191s. serial nu. 704,113.

Patented Sept. 8, 1914.

,Be it known that I, HARRY W. YOUNG, a citizen of the .United States of America, a.resident ,of Chicago, county of Cook, yandg State of Illinois, have invented certain new and useful Improvements in FusefHolderS,

of y which the following is a specification.

This invention relates to improvements in tholmal cut-outs for electric circuits, and more .particularly to tubular safety fuses of ,the refillable type f I` hemain objects of this invention are toprovide an improved form of safety fuse, or rei-llable holder and fuse element proper therefor; to, provide a strong and rigid double lwalled housing structure `or casing foninclosing the fuse element and capable of withstanding the gaseous vapor pressure produced by the sudden blowing of the fuse by Ishort circuiting under normal or any ordinary voltage; to provide a safety fuse which may be separable .into not more than two distinct complementary parts or members, each of substantially unitary charac ter, the minor constituent .elements ofwhich ,respectively may be so secured and linked together mechanicallythat .in the process of refilling the fuse the variouspa-lts or pieces cannot getaway or be mislaidby the operator or in any way becomeY separated or lost; to provide selective or lock-out means adapted to preclude the substitution of an improper fuse element;fto providespecially formed fastenings or Yterminal clams for the fuse element which shallbe adapte to retceive only fuses which have beencorrespondingly formed to fit the clampingcontacts; toprovide non-removable means, both vfor locking the `fuse element position and for locking the said complementary members together, and to so construct and a1'-- rangethe locking members that when they are notengaged orsettightly in their normal locking position it will be impossible tol closelyassemble the fuse holder orvfit 4the parts snugly enough' together to ymalieit enter or lit the corresponding terminals lo'f. a cut-out box o other mounting provided therefor in the circuitiv tobe protected.

Certain specific constrnctions embodying this invention areillustiatedin theaccomy panying drawings, `in which: i

Figure 1 is a centrallongitudmal section of a complete f use.}and,.f,use holder having ferrule type 'terminals and illustrating onev embodiment of thiS'iIlvention. Fig.' 2 isa .with one 0f' the .terminal caps permanently attached thereto, and having a fuse element clamped 111.918,09. Fig. 3 is a cross section through one end of the fuse and terminal on the line A7-A of Fig. l. Fig. 4 is a perspective, ;view of Ya fuse element proper adaptedlfpr the form of holder illustrated 1n. ig. Fig. ,5 is .a right vend elevation ofthefuseshown in'Fig. 1.' Fig. 6 is an end ,elevation of the central Aportion of the left. end of 4the -fuse 'shown in Fig. 1, and shows how the wire gauze is held in the vent through they axial locking stud. Fig. 7 1s aperspeetive view` Oia clamping member., Simllar .t0 the fixed member; Shown 'at the leitend of F ig 1, but having corrugations .disposed longitudinally instead of crosswise. F1g. 8 is a 'perspective view of a vmovable complementary locking member adapted to coperate with the fixed clamping member shown in Fig 7. Fig. 9 is a modifiedform 'of fuse comprising a pair of longitudinally corrugated broad plate terminalsconnected by a flexible fuse link and adapted for longitudinal insertion between clamping members formed as in 'Figs 7 and 8. Fig. 1 0 is a centrallon tion of another embodiment o this invention .and illustrates afuse element and casing having knife blade terminals. Fig. 11 .a icrosssection on the line B -B of Fig.'- 10. Fig'j12 is a longitudinal section thro h one of the terminals along the line C -C of Fig. 11.

.Inthe constructionshown in Figs. 1, 2, 8, 4, .and 6 the fuse as .a'whole comprises a double walled casing or housing member 1 having Ac.ox1ce ntric' walls 2 land 3 of insulating, material 'and' providedl with suitable outer terminal caps LLand-5, interior clamp-v ingmeans 6 and ,7- adjacent to said caps arid electricall" connected therewith, and a fusible strip o metal or fuse element proper 8 'adapted t be held removably by said clampin means, 4the fuse terminals and clampsfeing vspecially formed to prevent substitution offan improper fuse memberf iThe double wallfof the casing comprises theinner cylindrical frame wall 2 having a longitudinalppefning 9 on, one side, formed :at its ends to lcorrespond with the peculiar formation .of theadjacent clamps and adapted for edgewi'se' reception and 'removal of the fuse element'therethrough, and theouter closed coveringwall' Whiehjis adapted to gitudinall secside elevation of the inner casing member fit-closely about and is telescopically removable from the inner wall. These casing walls ma be made of any rigid, tenacious and dura le insulating material, preferably fiber.

Metal end caps

4 and 5, adapted to serve electrically as exterior or main fuse terminals, are arranged for inclosing the ends of the housing and are carried-nondetachably one by each of the ,saidlwall members.

Rigid metal frame members'12y and 13, formed eachwith a transverse end wall ordisk portion 121 and 131 respectively, are securely mounted within the ends of the inner casing member, one of which, illustrated at the left end of Fig. 1, is adapted for direct threaded engagement with the adjacent terminal cap 4, the latter being provided with an inwardly rejecting hollow stud 41 externally threaded gage the correspondingly threaded central perforation 122 inthe wall portion 121. The said rigid end member '12 is also formed with an inwardly projecting portion 123 terminating in a transversely disposed spacing brace 12s adapted to serve as a fixed clamp member and mounting brace for the frame, which as a whole is permanently attached, as by rivet 12* and the integral tips125 and 12 to the inner casing 2. The* tip 12 projects radially fromlthe perimeter of the end wall 121 at its upper edge and interlocks with the casing 2 to prevent relative rotation. The tip 12 projects outwardly from the inner end of the frame 12 through the casing 2 and is clenched /to lock therewith. The" adjacent terminal cap 4 is in similar manner permanently and rigidly attached to' the outer casingf3, as byv Arivets in thevferrule portion 43. The rigidly connected cap 4 'and outer casing 3 constitute substantially the outer of the said complementary housing members. The coactin'g hub 122' and hollow stud l41 may be formed inte ally on the inner and outer end'walll mem rs respectively by a stamping or spinning process, or both combined, after which the stud 41 is threaded by means ofa suitable hollow die and the barrel or hub 122 is' internally threaded to correspond therewith." 'l

At the opposite or plain noni-locking end of the housing, the rigidly mounted end member or frame13 is similar to frame 12 in general form andis permanently attachedl both to the inner casing 2 and to the end wall of the terminalfcap 5, as b a rivet 134 and screws 137 res ectively, t ewrivet' 13* being supplemented y integral tips 135 and 13 as on framef12, thus giving a' permanently unitary lcharacter to the'par'ts' so connected, and with the frame 12 constituting substantially the inner of the said complementary housing members.

The vnon-lockin end of the outer casing 3 is plain and a apted to slide' freely into to enter and ent s 'The usefelement-i place longitudinally between the ferrule 51 of the adjacent cap 5 `and the inner casing 2. By this construction the fuse housing may be separated into two distinct complementary parts simply by gripping .the two opposite ends of the assembled housing, as

at the

caps

4 and 5, and turning them oppotsitelyto -disengage the screw connection 41 at the locking end.

The clamping means provided at the ends of the casing each comprises the inwardly projecting branch or bracket portion 1211 or 13s respectively of the said end frame members 12- and 13, together with a movable member 15 or 16 respectively formed and adapted for clamping closely against the corresponding adjacent "rigid memberA by means of a lscrew 17, said members being adapted to vrec'eive theterminals 18 and '19 respectively ofthe fusible element 8 between. The fixed and movable clamp members are perforated in registry, and the perforation 1n each rigid-member is threaded to engage the adjacent clamping screw 17, the hole through the loose 4member being made plain and formed lar enough to clear the threads on the stem 0% the screw. The threaded portion of the clamp is depressed to form a deeper bearing hub or barrel for the threads. The inner wall 2 is also provided with perforauons 21 in radial alinement with the clamp perforations, to provide access to the said screws for turning them, and to per-v mit the heads normally to stand substantially HushI with the'outersurface of the inner wall, and to ba'ck out through the same enough to release' the

fuse terminals

18 and 19 when theouter casing 3 is removed.

The terminal' clamps, for the fuse element 'terminalllSflon the'other end, the flat end being provided with a longitudinal end slot 191 'adapted -to'facilitate inserting the flat end longitudinally Iinto place astride the screw 17 between the clamp members 133- and 16 and then pivotally swinging the corrugated end in'to place between the oppo- `site

terminal clamp members

123 and 15,

the end 18 having a transverse side slot 181 to receive the stem ofthe adjacent clamping screw 17.

A modification of the'clamping terminals adapted for longitudinal insertion of the fuse may be provided as illustrated' -in'Figs 7, 8, and 9, .he corrugations running-length-- wise insteadf crosswise.

l tself, as illustrated in Iiand 4E; comprises*A the terminals' 18 and 1 9 and a fusible strip adapted to carry a 'p predetermined current load connected therebetween as in ordinary fuses. The terminals may be modifiedtocorrespondfwith whatever shape of terminal clamping means contact by settin vthe casing members mafv is used and the corrugations may extend crosswise as in Figs. 1 and '4, or lengthwise as iii Fig. 9, butin any .case are ada ted to t 'esaid clamping members for s lppi into place when the outer casing is remove and the clamping screws l17. are loosened. Each of the clam ing screws 17 is provided with a head of suicient length to stand substantially lush with the outer surface of the inner casing when the screw isset tightly upon the terminal of the fuse held thereby, thus permitting the outer casing 3 to telescope readily upon the inner casing 2 when the screws 17 are set. This arrangement of' the screws serves to paravent assembling the outer casing-upon t the clamping screws have been tightened` and when the heads are projectingl the inner casing, thus precluding t e possi? bilit of putting the fuse into service with,- out avi first secured a proper clamping the screws. In order` to prevent either o the screws 17 from bein entirely removed from the rigid portion o the clamp, and also vto revent removal of the loose clampi mem rs 15 on 16 held in place thereby, t e inner ends of the screws are slightly headed or buxx-red as at 171 sufliciently to prevent withdrawal from the threaded hu of the clamp members.

The movable corrugated clamping member 15 is formed with outwardly turned ends or spacing members 151 standing substantially at right angles to the main body and adapted to reach normally to a point adjacent to but slightly apart from the lnner wall of the casing, by which arrangement the said member 15 is prevented from attaining a suicient degree of separation from the rigid member 12, loosened, to permit the insertion or substitution of a nail or any other straight fuse member in place of the regular specially formed fuse 8.

In case the fuse blows out it may be replaced by a new fuse as follows z--The complementary casing members are separated by releasing locking end. The terminal set screws 17 may then be loosened sufficiently to permit removal of the fuse terminals, whereupon the new fuse may be slipped into place and the screws tightened so as to give a rigid and thorough bearing contact, after which be telescoped and locked at 41 and the sa ety fuse as a whole placed back in the circuit.

Ample vent is provided for escape of the gaseous and vaporous products of fuse blowing, screened openings being provided at the ends of the housing. For this purpose the said hollow axial stud 41 is provided with a roll 20 of gauze or screen longitudinally disposed in the perforation where it is permanently locked in place by forming an ininner casing before beyondA itratedin Figs.

' non-se when the screw isl the screw connection -11 at the element 33, said slot being wardly turned bur or a series of burs 4* at the outer and inner ends of the opening.

the op osito end of the housing are pro- ;ded i? 11lend wall one or moia vent holes pre era, a up, arr n e s mmetrically about ythe gclinten lat ,gauze or screen .element 22 is held securely clam ed oetween y.the ,end wall elements 131' an 5. rl,` he holes 21' are preferably numerous and small so as to obtain the greatest strength for a given area' of vent and to prevent the auze rom being ruptured by the explosive orce of afblow-out. Gauze of copper wire is preferred for screening the vents as being the mosteicient iiame extinguisher.

order to provide a fuse embodying' the main features of this invention adapted for knife blade type of terminals, a somewhat modified construction is rovided, as illus- 10, 11, an 12, in which the `terminal blades 'antlferrule caps are assembled, either snbstantially inte ally, or are arably interconnected or partial disconnec ion. In this construction the outer casin 26 is permanently riveted. to the end cap 12 'said cap being of a cylindrical or ferrulew'shaperwith an end wall having a transverse central slot or opening271 of rectangular shape, through which projects lthe knife terminal 28. The said terminal consists of a sheet metal strip or stamping doubled back on itself at its middle point 281, and with its inner ends or arms 28 turned divergently outward per-y pendicularto the mainbody of the terminal and adapted to` tit closely against the inner lface of the cap 27 with one or more layers of gauze 29 between, in which position the said arms 282 are riveted securely in lace against the end wall of the cap. Vent oles 30, screened by the member 29, are provided in the end wall members 27 and 282 at one side of the terminal blade 28.

A longitudinally positioned locking screw 31 is provided at one side of and adjacent to the blade 28, opposite from the said vents 30, for attaching theabove described substantially integral portion of the housing to the complementary portion adapted to fit therein, said screw bein of the round head type with its stem proJecting through and fitting loosely in the adjacent outwardly turned arm 282 of the knife terminal and Withvthe inner shoulder of its head abutting against the outer side thereof, the end wall of the cap 27 being perforated to receive the head of said screw, and the edges or lips of the wall perforation being spun outwardly somewhat or otherwise formed so as to slightly overlap the head and securely hold the screw against removal from the end cap 27.

The inner casing 32 has a longitudinal opening 321 on one side to receive the fuse adapted for in- U-shape, the transverse portion 351 lindrical wall of the casingI and is securely sertion and removal of the fuse element. In the end of the casing 32, adjacent the terminal 28, is rigidly mounted and fastened by rivets 34, a frame or bracket member 35 of of which is disposed across the end of the casing 32 substantial] closing same. The lateral arms of the bracket 35 are formed to fit closely against the' interior ofA the inner 'casing where held by the saidl'ivets 34.

The adjacent clamp 36-37 for the fuse element 23 comprises a rigidly mounted bracket member 36, and a movable complementary member 37l ad ted to coact therewith., the rigid memberieing of U-shape with' its middle part 361 transversely corrugated, longitudinally disposed centrally ofthe housing and its ends 362 being riveted to the transverse end member 351 and the other secured to the adjacent end portion of the bracket 35. The movable member 37 is also U--shaped with its middle part corrugated to correspond with the coa'cting rigid member, and with vits ends 371 turned .outwardl adjacent to the op osite side of the brac et 35 to prevent su l cient separation of the clamp members 36 and 37 to permit insertion of a straight body.' The clam end 371 adjacent the end wall 1s roug cned or corrugated so 'as not to close in any case the vent liol'es 30.

The end wall portion351 of the clamp supporting bracket 35 isprovided with a threaded perforation'in' registry with land adapted to engage the casing lock screw 31 for detachably fastening the casing members together in telescoped relation. v

The opposite end of the inner casing 32 contains the inner end of a knife blade terminal and a clam constructed somewhat differently from tlie terminal 28 and clamp 36-37 just described, a relatively thin stri or blade member 38 being bent upon ,itse f at its central point 381 and inclosing a relatively thick plate 39, said pressed tightly together and riveted substantially integrally to form the blade terminal 40 projecting outwardly through the slot 411 in the cap'41, the ends of the thin strip 38 being bent outwardly to form the end wall 382 of the inner casing with the outermost portions turned longitudinally and formed for riveting to the interior of the cylindrical casing wall 32. The inner end 391 of the -plate 39 projecting axially within the housing is corrugated for seating the correspondingly corrugated fuse terminal 331, and adapted to constitute the rigid or seat member of the terminal clam at this the inner end of the casing 32. correspondingly corrugated member 42 is movably mounted adjacent the rigid member. The extreme inner end 392 of the plate 39 is turned perpendicularly against the'cyvfastened, as by 'along lits lateral edges turned transversely, one

parts beingv ldrawing the parts closely together. feature prevents riveting, to the adjacent endl 381 of the blade stri 38, thus impartin to the fixed clamp mem er the nature of a id bracket. The said cap 41 on this last described end is ada ted to lit closely over the outer casing 26' w en the parts are assembled, but is' not riveted or otherwise rigidly fastened to any of the adjacent parts. This cap, however, is prevented from complete removal b means of a slot and groove engagement with the knife blade 40. To this end the said plate 39, constituting the central portion or layer of the blade 40 is cut away of the .fuse casing and a point adjacent the outer extremity of the blade, forming grooves '401 inthe edges of the blade, and the said slot 411 inv the coacting cap is provided with a tongue 41.2' at each en d, adapted :to slide in the guide groovesv 401 which `tongues may be turned horizontall for assembling the cap initially and t en bent back into theirnormal transverse ositions within the terminal slots, whereby t e cap is -permitted t0 slide outwardly to give access 4to the adjacent set screw and to permit removing or inserting a fuse, after which it may fbeslid back inl place over the outer pasing where it is securely held fbyl friction against any ordinary or accidental force The terminal clamps j elements used in this style of fuse, as in the first described construction, may be formed with thecorrugations extendin either transversely or longitudinally. T e clamping screws 43 are formed substantially like the corresponding screws 17 vin the rst described structure and operate in the same way. Access .to the heads of these screws 43 is provided for by ythe

perforations

44 and 45, respectively, in lalinement therewith throu h the casing 32 and bracket35 at the loc ing end of the housing and through the casing 32 and strip 38s at the opposite end.

In order to replace a fuse, the movable cap 41 is slid back toward the outer end of the blade 40; the longitudinal lock screw 31 on the opposite end is disengaged from the inner end wall 351 and the two complementary casing members are drawn apart, whereupon the clamp screws 43 may be loosened and the old fuse may be removed or replaced. The p arts may be reassembled by a reverse operation.`

In assembling the fuse, the clamping screws 43 must first be set in order for the outer casing to clear the heads. Thus looseness at the clamp contacts when in use is precluded. When the casings are brought together the screw31 prevents complete telescoping until it is set by screwing into the adjacent end 351 of the inner member rlallid Vis inserting the fuse holder between the end 382 y in circuit without first setting up the screw' 31 and thereby securing a good electrical contact between the blade members 282 and; the clamp holding bracket 351.

In the vknife blade type of safety fuse the clamps at each end are substantially valikel with respect to the fuse grippin surfaces and the terminals of the fuse. W enever a stif, heavy fuse for large currents is to be used the corrugations preferably are run crosswise, but when a small, flexible fuse for small currents is to be used, the corrugations preferably are run lengthwise. By this system a safety check is rovided against inadvertently inserting a arge capacity fuse in a circuit designed for a small current only.

All of the metal arts of a fuse of the character herein set orth, except the screws and rivets, when formed and arranged in accordance with this invention may be manufactured readily in the form of Sheet metal stampings, thus assuring absolute uniformity of structure and low cost. Fuse parts made as herein described from sheet metal are preferred to castings because of greater strength forl a given weight of metal and greater uniformityin detail and natural finish without special treatment.

It is to be noted that the inner ends of all clamps made in accordance with this invention are formed with transversely disposed radial web or partition members as 12s, 151, etc., adapted to preclude the lateral insertion of wire or other substitutes which otherwise might be clamped under the heads of the

screws

17 and 43.

The extreme simplicity and unitary character of the two complementary parts are to be especially noted, each being so organized and arranged that its several parts though at times loosely connected are inseparable, thus preventing accidental dropping or loss of any of the parts, such as screws, clamping members or caps. It is clear that a fuse constructed in accordance with this invention is proof against the insertion of any but a specially formed fuse member, and that no substitute can be readily formed therefor, and hence the possibility of any improper substitute being used is rendered very remote.

Although the drawings and descri tionl are not limitedto one embodiment o this invention, it is to be understoodthat no attempt has been made to, illustrate all practica embodiments, and thaty numerous de tails of the constructionfshown ma 'be altered or omitted without. departing rom the spirit of this invention, as defined by the following claims.

I claim 1. In a safety fuse of thecharacter described, a casingin combination with terminal clamping members contained in said spondingly corrugated in registry casing and adapted to grip the ends of a fuse element, one of said clamping members comprising a pair of coacting jaws correon their opposing faces, one of said jaws being rigidly attached to said casing, and the other or movable jaw bein formed with a back portion extending adjacent to the opposite side of said casing and adapted lto abut radially thereagainst when the jaws are opened, and thereby limit the opening of the jaws, substantially as and for the purpose set fort 2. In a safety fuse of the character described, a casing in combination withterminal clamping members contained in said casing and adapted to grip the ends of a fuse element, one of said clamping members comprising a pair of coacting jaws correspondingly corrugated in registry on their opposing faces and a clamping screw therefor, said jaws being provided with oppositely and outwardly disposed guard shoulders, one on the inner end of each jaw and extending adjacent to the opposite sides respectively of said casing and adapted thereby to prevent inserting any fuse body between the clamping means and the sides of the casing, substantially as and for the purpose set fort 3. In a safety fuse of the character described, a cylindrical casing member of insulating material,in combination with a terminal member mounted ri idly in oneend of the casing, said termina member comprising a disk portion itting closely within the extremity of said casing and an axially disposed clamping jaw member formed integrally with said disk portion, and a movable complementary jaw member adapted to be clamped rigidly to the first said body for holding a fuse end. v

4. In a safety fuse of the character described, a cylindrical casing member of insulating material, in combination with a terminal member mounted rigidly in one end of the casing, said terminal member comprising a disk portion tting closely within the extremity of said casing and an axially. disposed clamping jaw member formed integrally with said' disk portion, and a movable complementary jaw member adapted to be clamped rigidly to the first said body for holding a fuse end, said terminal parts consisting of sheet metal stampings.

5.1 In a safety fuse of the character described,a cylindrical easing member of insulatingl material, in combination with a stamped sheet metal terminal member mounted rigidly Ain one end of the casing, saidL terminal'member comprising a disk portion fitting closely within the extremity of saidcasing and van axially disposed clamping jaw'membe formed integrally with said disk portion, and a moveblecomplementary jaw member adapted to be clamped rigidl to the first said body for holding a fuse en said fixed disk and Jaw stamping having radially projectin tips adapted to engage the casing for rigi attachment of sai stamping thereto. l 6. In a double walled safety fuse of the character described, two complementary housing members each comprising a cylindrical casing tube of rigid insulating material and an end caprigidlv attached thereto, the inner tube having c amping members mounted rigidly in each end adapted for holding the ends of a fuse element, the cap on the outer tube havin an inwardly projecting externally threa ed axial stud member andthe adjacent clamping member being axially perforated and'threaded at its outer extremity to receive and rigidly interlock with thesaid cap stud, substantially as and for the 'purpose set forth.

. members respectivel 7. Inl a double walled safety-fuse of the character described, the combination of a pair of complementary cylindrical housing members, both closed atthe same end and adapted to telescope closely one within the other, said members having axial screw lthreaded enga ement at the said closed ends. 8. In a double Walled safety fuse of the character described, the combination of a pair of complementary cylindrical housing members, both Iclosed at 'the same end and adapted to telescope closely one within the other, said members having axial screw threaded engagement at the said closed ends, A

the threaded part on the outer member being integral with the adjacent exterior fuse terminal contact and the correspondingly threaded part on the inner member being integral with the -fuse element holder. -'9. In a double walled -safety fuse of the character described, a pair of telescopically separable casing members, in combination with clamping members carried by the inner casing member at'the opposite ends thereof and 'adapted to rigidly engage the ends of a fusible element, exterior terminal members' secured4 to the inner and outer lwall at the opposite ends of the" fuse, said c amping and terminal members being substantially contiguously disposed at each end respectively, one pair being permanently connected, and fastenin means adapted and arranged for detachably locking the other pair together.

l0. In a double walled safety fuse of the character described, a pair of telescopically separable inner and outer casing members having transverse] positioned in ner and outer closing mem ers respectively at one end of the fuse, in combinationwith a longitudinally disposed externally operable screw havmg its head held rotatably in the outer transverse closing member land said inner closing member having a threaded perforation adapted to receive said screw in operative engagement for telescopically reciprocating the inner and outer wall members and for locking the said closing members securely together.

' 11. In a safety fuse casing, an end wall comprising an'outer member and an inner member in combination with one or more layers of metal gauze clamped between'said end members, said clamping wall members having one or more perforations arranged in registry to give vent through said gauze and wall members to ythe gaseous vapors generated when a fuse blows.

12. In a safety fuse of the character described, outer and inner casing members adapted to telescope one within the other, said members having transverse closing walls at one end formed and arranged centrally for coaxial threaded engagement one Within the'other, one Wall having a threaded perforation therein and the other an externally threaded stud adapted to engage said perforated member, and the stud carrying member having an axial perforation containing metal gauze and adapted to serve on a vent for the fuse.

13. In a safety fuse ofthe character described, a sheet metal stamping comprising a bracket having transverse end portions adapted for fastening to one side of the casing and an intermediate longitudinal portion corrugated to receive a correspondingly formed fuse terminal.

14. In a safety fuse of the character described, a casing in combination with a terminal clamp therein comprising a pair of sheet metal stampings having longitudinally disposed opposing faces correspondmgly corrugated to mesh together, and

means for binding said clampvmembers together, one of said clamp members being rigidly mounted on one side of the fuse casing and the other being formed with transverse backwardly projecting portions adapted toA abut against the opposite side of the fuse casing and thereb limit separation of said clamp members, su stantially as and for the pur ose set forth.

15. A re llable fuse holder of the character described, comprisin an inner casin having corrugatedfuse ho ding means. and having a longitudinal side 4opening correspondingly formed and adapted to admit a fuse corrugated to fit said holding means, in combination with an outer casing telescopically removable and completely surrounding said inner casing.

16. In a two part safety fuse holder, a combined clamp jaw 'disposed axiallyA in the casing, an end wall disposed transversely and connected at one edge to the outer end of said jaw member, and a casing lock mem,- ber formed integrallyfrom sheet metal, said lock member comprising an interiorly iir.

threaded inwardly projecting axial flange struck up about a central perforation in said end Wall.

17. In a two part safety fuse holder, a combined clamp jaw, end wall, and casing lock member formed integrally from sheet metal and secured to the inner casing, the clamp jaw being disposed longitudinally and having a transverse internally threaded barrel formed thereon and adapted to receive a clamp screw, and the end Wall having a longitudinal barrel formed thereon and threaded to engage the complementary outer casing member, said end member at one edge being joined to the outer end of said jaw.

18. In a device of the class described, a sheet metal stamping, comprising a longitudinal axially disposed corrugated jaw member perforated and threaded to engage a clamp screw, in combination with a transverse end Wall member axially perforated and threaded to engage a coacting member, said jaw member having on its remote end a transversely disposed support wall terminated by a small locking tip and the said Wall member having an oppositely pointing locking tip, substantially as and for the purpose set forth.

19. In a double walled safety fuse of the character described, a pair of telescoping casing members each having a closing wall across the same end, said Walls being adjacent when the casing is assembled, and means adapted for detachably clamping said walls together.

20. In a double Walled safety fuse of the character described, a pair of telescoping casing members each having a closing Wall across one end, said Walls being adjacent when the casing is assembled, one of said end Walls having a threaded perforation and the other a threaded project-ing member adapted to enter said perforation and engage the threads thereof for clamping said end Walls together.

Signed at Chicago this 26th day of April 1913.

HARRY W. YOUNG. witnesses:

LEOPOLD A. HEINE, FRED M. Davis.