Patented Oct. 29,1946 \ 2,410,244 UNITED STATES PATENT OFFICE 2,410,244 FUSE William 0. Schultz, South Milwaukee, Wis., as signor to Line Material Company, Milwaukee, Wis., a corporation of Delaware Application June 25, 1943, Serial No. 492,291 I 5 Claims. This invention relates to power fuses and more particularly to fuses of the bayonet type. In certain cases where bayonet type fuses are employed it is desirable to use standard fuse links of the type which does not include a built in biasing ‘spring; but at the same time it often is- desirable or necessary to provide suitable spring means operative to bias the link and thereby quicken the separation of severed fuse-link parts when blowouts occur. The primary object of the present invention is to devise a practical fuse construction which is Well adapted to utilization of standard links (Cl. 200-117) 2 readiness to function as an expeller in event of a blowout. - A preferred embodiment of the invention is il lustrated by the accompanying drawing, where of: ~ . Fig. l is a sectional view depicting the lower end portion of a bayonet fuse housing together with a fuse-cartridge and fuse-link-the ‘car tridge and link being shown during an intermedi ate stage of link installation; ~ Fig. 2 is substantially a repetition of the lower portion of Fig. 1, except that it depicts the fuse link fully installed and shows the ears of the metal clip bent to effect an anchorage of the of the above-indicated variety while providing the desired spring bias. 15 fuse-link to the cartridge terminal and biasing Another object is to achieve simplicity of design spring; . and consequent manufacturing economy. Fig. 3 is a view taken along the line 3--3 of Fig. Still another object is to facilitate the installa 2; and tion of replacement fuse-links so that servicing Fig. 4 is a view taken along the line 4—4 of the fuses in the ?eld will not be inordinately 20 of Fig. 2 ‘ time-consuming or entail the exercise of any con Inasmuch as the present invention is not con siderable skill. cerned with the fuse housing construction, there A further object is to provide a movable spring has been shown only the lower portion of such a biased fuse-link engaging member urged to fuse housing. This comprises a tubular porcelain link extracting position and normally engaged 25 housing member I, shown fragmentarily, in which by a resilient friction contact which relieves the fuse-link of excessive stresses while the fuse-car- ‘ is located a conductive sleeve 2 secured within the housing by means of a cement or fusible metal tridge containing the fuse-link is in circuit clos ?ller 3. Sleeve 2 is suitably apertured at 2a to ing position, and also to so correlate the biasing receive a line conductor and is provided with one spring with the fuse structure as to protect it 80 or morebinding screws 4 by means of which the from the destructive effects of an are upon rup line conductor is clamped. The sleeve is bored ture of the fuse link. at 2?) concentrically with the housing to receive ' A prominent feature of the present invention and make electrical contact with the lower termi resides in a novel fuse-cartridge terminal con nal of the fuse-cartridge, which latter is insertable struction which incorporates within itself both a 85 into and withdrawable from said sleeve via the biasing spring and contact members, so vco upper end of the housing. ordinated as to facilitate insertion and withdrawal The fuse-cartridge comprises an elongate tube of the cartridge into and from the fuse hous 5 of horn ?ber or, preferably, of “Bakelite” lined ing without requiring any electrical connection with horn ?ber, and is threaded externally at its to be made by the serviceman after the cartridge 40 upper end to receive a ferrule '6 which, in turn is is ‘in place, and so designed that the fuse-link threaded to receive a removable conductive cap ‘I. is properly and fully spring-biased before the The upper ferrule and cap designs are to be re cartridge is inserted in the housing, and so con garded as purely conventional and subject to a. tinues thereafter. variety of modi?cations. The invention does not Another feature consists in the provision of a 45 lie in that part of the structure. simple metal terminal clip which can easily be There is secured to tube 5, toward the lower applied to the ?exible leader of a standard fuse - end, a metal thimble 8. This encircles the tube link and which is of such dimensions that it can and provides support for the upper end of a be passed through the fuse cartridge bore while tubular member 9 which is slotted lengthwise to attached to the fuse-link leader and thereafter 50 form several depending resilient contact ?ngers bent, without di?iculty, so as to effect an anchor 9a spaced circumferentially about tube 5. These ing engagement and good electrical contact be contact ?ngers are yieldable radially of the tube tween the fuse-link and the adjacent cartridge and are designed to eifect spring-pressed en terminal while contemporaneously retaining the gagement with the bore 2b of sleeve 2. biasing spring under compression and. thus in 55 The lower end of thimble 8 is of reduced di 2,410,244 4 ameter and threaded to engage the upper end of a helical spring H) for which it affords an an chorage. Said spring encircles the lower end of tube 5 and is secured at its lower end to a ter minal member II, which is supported by the spring and is movable axially of tube 5 by stretch ing and compressing the spring. The spring I0 is disposed, in its entirety, ex teriorly of the tube 5 and the terminal member the frictional engagement of the contact ?ngers 9a with the terminal member H and conductive sleeve 2 will be of suf?cient magnitude to effec tively counteract the expansive force of the spring I!) and thus relieve the fuse-link l2 of the greater part of the stresses which would otherwise be imposed thereon by the expansive forces of the spring. It will of course be under stood that frictional forces exerted by the con ll. Consequently, any are established during 10 tact ?ngers 9a will not entirely overcome the ex pansive forces of the spring l0 since the spring circuit operations will not cause injury to the must be free to withdraw the flexible leader 15 spring since the latter is positioned out of the upon rupture of the fusible section 13 of the path of hot destructive gases generated by the fuse~link. are and expelled from the tube. When the fuse-link blows, spring I0 is effec The fuse link 12 is of a standard type com 15 tive quickly to withdraw and expel from the prising a fusible section l3 together with a but cartridge all that portion of the fuse-link which ton-head upper terminal l4 and a ?exible conis below the point where disjunction occurs. ductive leader [5. Button head terminal I4 is What is claimed is: gripped between ferrule 6 and cap ‘I and serves 1. In combination, a fuse~cartridge, a fuse as means for supporting the link at'its upper end 20 link within said cartridge and having a terminal as well as for effecting electrical connection anchored at one end of said cartridge, the other thereto. end of said cartridge being open, said fuse-link A tubular metal clip 16 is compressed upon and including as its second terminal an elongate con thereby secured to leader H3 at a predetermined ductive leader projecting out of said open end of point. As shown in Fig. 1, clip 15 has two_o-pthe cartridge, a helical spring encircling said posite downwardly extending pliable ?ngers Ilia cartridge adjacent said open end, one end only and Nib, which ?ngers are designed to be bent of said spring being anchored to said cartridge outwardly and upwardly, as shown in Fig. 2, to at a point somewhat removed from the open end hookingly engage terminal member I l-see Figs. thereof, a tubular member encircling said spring 2 and 3. and attached at one end to said cartridge, said Since the fuse-link must be inserted in the tubular member comprising a plurality of resili cartridge from the upper end thereof, it is ob ent contact ?ngers extending lengthwise of said vious that metal clip l5 must initially be dicartridge, and means carried by said leader for mensioned to pass through the bore of tube 5. anchoring said leader to the unanchored end of Hence, ?ngers lSa and [6b are made to extend said spring for maintaining said spring under parallel to leader l5, as shown in Fig. l, but capable easily of being bent to form laterally compression and said fuse-link under tension, extending ears, as shown in Fig. 2, after the said means being engaged by said resilient con tact ?ngers whereby the expansive force of said fuse-link is in place. ' When the fuse-link is fully installed, spring spring is in part nulli?ed. I0 is under compression and the link correspond 2. In a fuse of the class described, a fuse car ingly under tension; but when free, the spring tridge having an open end, an expansible spring encircling said open end and having one end thereof secured to said cartridge at a point re is extended lengthwise so that terminal member ll occupies a lower position, as indicated in dot and dash lines in Fig. 1. Said spring must be compressed by forcing terminal member (I to approximately the position in which it is shown in full lines in Fig. 1, before the ?ngers lSa and 46b are bent outwardly and upwardly, per Fig. 2, mote from said open end, a tubular terminal se cured to the other end of said spring having a bore concentric with and receiving the open end of said tube, said tubular terminal in part being encircled by said spring, a contact member se to form the aforementioned ears which hooking~ 50 cured to said cartridge and encircling said spring ly engage said terminal member. Whenever and said terminal, said contact member includ necessary, ?ngers 16a and [6b can be bent back ing contact ?ngers frictionally engaging said ter to approximately their original form, thus per minal, and a fuse link engaging said terminal and mitting the fuse~link to be removed from the normally holding said spring under compression. cartridge. 3. In combination, a fuse cartridge, a fuse link Terminal member I I is contacted by the lower of the standard type within said cartridge having ends of contact ?ngers 9a, thereby establishing a terminal anchored at the upper end of said a conductive path via said contact ?ngers be cartridge, the other end of said cartridge being tween sleeve 2 and terminal member I l . Accord open, said fuse link having as its other terminal ingly, spring II] is not required to carry enough 60 a flexible conductive leader projecting out of the current to cause injury thereto. open end of the cartridge, a spring encircling Terminal member II is, preferably, a brass said cartridge at its lower end and having one casting formed to present at its lower end two end anchored thereto, a terminal member car spaced parallel ?at sides which, in Fig. 3, are ried by the other end of said spring at a point identi?ed by reference numerals Ila and llb. 65 adjacent the open end of said cartridge, said ter Said ?at sides are effective to provide ample con minal member having a passageway co-termi tact area with ears Ilia and l?b, while at the nous with said open end of the cartridge and gen same time serving to prevent rotation of clip !6 erally coaxial therewith, a metal clip attached to relatively to said terminal member after the link said flexible leader and having a plurality of pli is installed. 70 able ?ngers which initially extend generally par The resilient contact ?ngers 9a frlctio-nally en~ allel to said leader so as to enable said clip to gage the terminal member H and are bowed pass through the bores of said cartridge and ter radially outwardly of the tube 5, as clearly illus minal member, said ?ngers being bent after trated in the drawing, to frictionally engage the passing through the bores of said cartridge and conductive sleeve 2. It is contemplated that 76 terminal member to form ears projecting radi 2,410,244 5 ally from said leader and engaging said terminal member whereby said spring is maintained un der compression and said fuse link is tensioned, and a, resilient contact carried by said cartridge frictionally engaging said terminal member to provide a counteracting force which in part nul li?es the expansive force of said spring. 4. In combination, a fuse cartridge, a fuse link having a ?exible leader within said cartridge and 5. In combination, a fuse cartridge, a fuse link having a ?exible leader Within said cartridge and having a terminal anchored at the upper end of said cartridge, the other end of said cartridge being open, a spring encircling said cartridge at its lower end and having one end anchored thereto, a tubular terminal member carried by the other end of said spring and having a bore concentric with and receiving the open end of having a terminal anchored on one end of said 10 said tube, said ?exible leader having at its lower cartridge, the other end of said cartridge being end a plurality of bendable arms, said arms be open, a biasing spring encircling said cartridge ing bent after passing through the bores of said near the open end thereof, and having one end cartridge and terminal member to form ears pro anchored to said cartridge, a movable terminal jecting radially from said leader and being effec member carried by the other end of said spring, 15 tive to hold said spring under compression and said fuse link including as its second terminal a to tension said fuse link, and a resilient contact pair of bendable arms, said arms, when bent, be ing operative to engage said movable terminal member and to hold said spring under compres sion and said fuse link under tension, and a re silient contact carried by said cartridge friction ally engaging said movable terminal member and in part nullifying the forces imposed on said fuse link by said spring. ‘ carried by said cartridge frictionally engaging said terminal members to provide a counteract ing force which in part nulli?es the expansive 20 force of said spring. WILLIAM O. SCHULTZ.