US2270225A - Fuse link construction - Google Patents

Description

Jan. 13, 1942.

A. G. STEINMAYER FUSE LINK CONSTRUCTION original Filed Nov. 16, 1934y Olm Patented Jan. 13, 1942 Emst/63270225 UNITED STATES PATENT OFFICE y FUSE LINK CONSTRUCTION Alwin G. Steinmayer, South Milwaukee, Wis., as-

signor to Line Material Company, South Milwaukee, Wis., a corporation of Delaware Original application November 16, 1934, Serial No.

Divided and this application November 24, 1941, Serial No. 420,295

39 Claims. (Cl. 20o-117) This invention relates to improvements in tension type fuse links.

The subject matter hereof has been divided from my copending application Serial No. 753,358,

filed November 16, 1934, pursuant to Patent Ofan expulsion fuse tube, whereby the tension of the fuse link may be set at a standard value prior to its incorporation into a fuse tube.

Another object is to provide a factory tensioned fuse link for replacement in an expulsion tube which will be expelled from the tube by the tensioning spring when the fusible section of the fuse link is severed.

A still further object is to provide a factory tensioned fuse link in which the fuse link is provided with means for -guiding the spring which tensions the fusible section of the link.

It is also a further object, to provide a fuse link having a tensioned fusible section and a. rigid section expellable from an expulsion fuse cartridge by means of the tension spring when the fusible section is severed, the rigid section serving as a guide to the spring and maintaining its direction of movement from the cartridge substantially unchanged and thereby compelling the flexible portionof the link to move from the cartridge.

It is still another object to provide an elongated rigid section which may be actuated, when the fusible section of the link is severed, to a velocity greater than would be possible with the ilexible'section alone.

It is also another object to provide a flexible fuse link with a portion adjacent the fusible section and which is less fusible than the flexible portion of the link, thereby keeping the metallic gases generated by the arcv at a minimum and consequently shortening the time during which thelarc will continue.

It also is an object to provide an assembled tensioned fuse link in combination with an arc suppressing material which will destroy or in' terrupt an arc created after the fusible sections of the link have been separated.

In the drawing:

Figure l is a view in side elevation of a fuse.

tube with a portion broken away to show a fuse link embodying this invention mounted therein.

Figure 2 is a view in side elevation of the fuse link shownv in Figure 1 and embodying this in vention, portions being broken away to show the inner elements.

Figure 3 is a view similar to Figure y2 showing a further modified form.

Figure 4 is a view in vertical section showing a tensioned and arc extinguishing fuse link embodying this invention.

Throughout the several views, like parts are referred to by the same reference characters.

The expulsion fuse cartridge shown in Figure l comprises an electrically non-conductive tube I, an upper tubular g contact terminal 2 to which the tube I is threaded, a closure cap 3 threaded to the terminal 2, and a lower contact terminal 4 through which the tube I extends and to which ,it is secured. The lower contact is provided with a link engaging clamping bolt 5 threaded into the boss 6 on the terminal l. This boss is slotted transversely relative to the bolt 5 to receive the flexible end of the fuse link, as will more particularly be described hereafter.

'I'he fuse link shown in Figures l and 2 comprises an upper contact cap I seated on the upper terminal 2 and connected by the portion l to the strip 9 which is notched at I0 to provide an area that may be easily severed to adapt it for insertion in other types of fuse tubes than that shown. The strip 9 is secured by means of solder I I to a strain wire I-2 having a high melting point and to a` fuse wire I3 having a low `melting point. Both of these wires I2 and I3 are secured by solder Il to the flexible wire 2I,

as shown in Figure 2.

As illustrated in Figure 2, the stripy 8 has an area I1 reduced in width to be received in the .insulating tube I8 which surrounds the strain wire I2, fusible wire I3, and flexible wire 2 I. In Figures l. and 2, a coil spring l5 engages the lower end of the tube I8 by means of a nut washer 3l threaded on the spring and is coaxial with the flexible wire 2I. The upper end of the spring 35 is crimped into engagement with the upper end of the flexible wire 2| to exert a pull on the strain wire I2, thus maintaining the strain wire under tension. The flexible wire 2I extends to the lower opening of the tube I and is bent back upon the outer side of the tube to position the end 23 in the slotted lug 5 on lower contact terminal 4 to be clamped by means of the clamping bolt 5.

lIn Figure 3, the rod I5 is secured in any suitable manner (such as soldering) at 33 to the flexible wire 34. A tube Il surrounds the rod I and spring 35 which is coaxial with the rod and is engaged with the upper end thereof at 35. Seated on the lower' end of the tube is a nut washer 31 threaded on the lower end of the spring and holding the spring under tension. The arrangement of the elements in Figure 3 is the same as that in Figure 2, except that the rod I5 in Figure 3 is substituted for that portion oi the flexible wire 2| which extends into the tube I3 in Figure 2. y

Figure 4 illustrates the invention disclosed in Figures 1 to 3 inclusive. The fuse link comprises a contact cap 45, a fusible section 46 secured to the cap and to the rod 49. Surrounding the fusible section is a compound of arc extinguishing material 48 which is enclosed by the insulating tube 50. A cap or plug 5| closes the bottom of the tube and serves as a seat for the spring 52 and is centrally apertured to receive the rod 49. The plug 5I also serves to retain the material 43 in the tube if such material is made in powder form. In this form of the invention, the insulating tube 50, cap 45, and plug 5I will conne the arc extinguishing material. The spring 52 is held under compression between the plug 5I and washer 53 by means of the wire 46 and rod 43 to which the washer 53 issecured by soldering. The rod 49 is likewise secured to the flexible section 54 of the fuse link.

From the foregoing description, it will be observed that each of the embodiments of the invention disclosed herein is provided with guiding means for the fuse tensioning springs. In Figures 3 and 4, the guiding means comprises, respectively, the rod I5 in Figure 3 and the rod-43 in Figure 4. In Figure 4, the spring 52 is under compression, and therefore the rod 49 holds the spring from lateral movement intermediate the ends. In Figure 3, the spring 35 is elongated so that it is pulling on the upper end of the rod I5. In this latter form, the spring naturally will tend to remain coaxial with the spring link. However, when the fuse wire I3 and tension wire I2 are severed, the spring impels the rod I5 toward the lower end of the tube I8. If the rod I5 is not provided, there would be some tendency for the spring to jam within the walls of the tube I3, although this would not be a serious matter in a carefully constructed -fuse link such as shown in Figure 3. As a matter of fact, the tube Il itself will produce to a considerable extent In Figure 2, I have not illustrated guiding means constituting a portion of the fuse link proper. However, I have shown the tension springs disposed in the tubes enclosing the fusible sections of the fuse links. tube surrounding the spring acts as the guide for the spring and holds the spring throughout its length substantially coaxial with the fuse link.

When the fuse wire I3 and tension wire I2 are severed, the spring will cause the link to move relatively downward with respect to the tubes and toward the open end of the cartridge I. The impetus attained through the action of the spring will be manifested in a very high velocity of the severed end of the link toward the open end of the fuse cartridge I. Even after the spring has spent its energy, the kinetic energy of motion of the fuse link will cause the link to continue its movement until it has been expelled from the fuse cartridge.

the foregoing noted results produced by the rod l' The portion of thel Thus, it will be seen that a fuse link has been provided in which the tension exerted on the fusible section may be set at a predetermined value prior to its insertion in a fuse cartridge and in which the expulsion action is positive and not dependent upon any possible expelling effect that may arise from the arc. As a matter of fact, the tendency is to extinguish the arc much quicker than it would ordinarliy be extinguished in a non-tensioned fuse link.

The operation of the device shown in Figure 4, when expelling the fuse link from a fuse cartridge, is substantially like the action of the device illustrated in Figure 2. However, there is an added feature to the form illustrated in Figure 4 which embodies a material surrounding the fusible section of the fuse link and which contains material from which water vapor or other arc extinguishing gases may be evolved under the iniiuence of an arc to impose in the path of the arc the equivalent of a resistance to the ilow of current. I prefer materials such as boric acid which give off water vapor under the influence of the heat of an arc Ifor the reason that it has been found that water vapor is extremely effective in extinguishing an arc. Thus, it will be seen that in the form illustrated in Figure 4, I obtain a separation of the fuse sections in a minimum space of time and also secure the extinguishing of the arc much sooner than it would be extinguished without the evolution of water vapor. While I have stated that I prefer material such as 'boric acid, it will be understood that I may use other materials which will evolve either water vapor or gases such as hydrogen which will effectively destroy an arc.

It will be noted that in the structure illustrated in Figure 4 the material 48 provides the equivalent of a small bore of substantially the same size as and enclosing the fusible section 45 of the link. The effect produced by this small bore upon an arc is to confine the arc to a limited space and consequently greatly increase the resistance to flow of current through the bore when the fusible section has separated. While I have indicated that I prefer boric acid as an arc extinguisher, it will be obvious from the foregoing that a sleeve of electrically non-conductive material, such as rotten stone, maybe used for the sole purpose of restricting the arc path and thereby suppress the arc sooner than the arc would normally be suppressed if the sleeve is not provided. There conceivably are conditions under which a restricted path will serve to suppress an arc justas satisfactorily as water vapor or other uids. For this reason, I do not restrict all of the claims to the use of boric acid or other volatilizable material. Figure 4 illustrates a novel method of suppressing an arc at the same time that the fused sections of the link are being separated by the spring. Therefore, claims predicated upon the invention disclosed in Figure 4 are intended to cover any equivalent arrangement producing the same results.

When this invention is used without arc suppressing material, I prefer the arrangement shown in Figure 3 or its equivalent. In the links illustrated in Figures 3 and `4, I; have provideda rod section I5 and 49, respectively, each provided with an expulsion spring concentric therewith.

In the Figure 3 link, the spring 35 is under tension, while in the Figure 4 link, the spring is under compression.

One of the advantages of having a portion of the link constructed -of a solid rod is ln the fact that the possibility' of the metal being vaporlzed by the arc between separated portions of the link is reduced to a minimum. It has been found that the fine strands of a flexible conductor will heat more readily and accordingly vaporize more freely than a single large conductor, such as illustrated in Figures 3 and 4. Therefore, it is desirable to place a single solid conductor in the link between the flexible section and the fusible section. vThe solid conductor spaces the flexible section of thelink from the fusible section and prevents the arc from reaching the more easily fusible strands of the flexible section.

A further function of the rods l5 and 49 is to serve as means to which a high velocity may be positively and quickly imparted and which will tend to maintain a substantially straight line movement after motion has been imparted thereto by their respective springs. In those modifications of fuse links which are not provided with rod or rigid conducting section, the flexible portion of the fuse link tends to interfere with the springs when the latter are relieved of their tension. While I have indicated that the use of a rigid vsection in the fuse link is desirable, nevertheless, those fuse links which are not provided with rigid sections in the link give satisfactory service, because I have provided a rigid member in the form of an insulating tube which guides the spring and the flexible section of the link and thereby assists the spring in imparting a maxlmum velocity to the link in the quickest possible time. The rod section of the link gives the added feature of protecting the flexible section against fusion.

I claim:

1. A fuse link comprising a pair of terminals, a fusible section connecting the terminals, a sleeve of insulation surrounding the fusible section and carried on the link, ra strain element connected between the terminals and lying within the sleeve and wholly out of contact with the fusible section, and a spring carried by the link,

said spring being under stress tending Vto separate said terminals.

2. A renewable fuse link comprising, a fuse tube, a relatively infusible terminal at one end of said fuse tube, a conductor including a flexible lead extending out of the other end of said fuse tube, a strain wire interconnecting said terminal and said conductor, a fusible element interconnecting said terminal and said conductor, said fusible element being in the form of a wire 'the length of which betweensaid terminal and s.'

said conductor is-substantially greater than th'e distance therebetween, and a spring reacting .against said fuse tube and tensioning said strain wire.

3. A fuse link including a fusible section, a

relatively rigid section, and a flexible' section' electrically connected by said rigid section to said fusible section; in combination with a spring concentric with said rigid section and comprising no portion of the circuit through said link, said spring being connectedat one end with the fusible section and having its tension exerted between the ends of the fusible section, and an insulating member interposed between the other end of said spring and said link, whereby said spring is held under tension.

4. A fuse link including a fusible'section, a relatively rigid section, and a flexible section electrically connected by said rigid section to said fusible section; in combination with a spring con- 75 washer threaded on the tube engaging end of` centrically related thereto and comprising no portion of the circuit through said link, a tube surrounding the fusible section, and means engaging one end of said tube with the corresponding end of said fusible section, said spring being held under tension by a portion of the link intermediate the ends of said tube and by the end of said tube remote from said fusible section.

i 5. A fuse link comprising a terminal portion, a fusible section, a flexible section, an insulating tube surrounding the fusible section, said tube being engaged with the terminal portion, a helical spring concentrically related to said flexible section and including means connecting one end of said spring and the flexible section, the other end of said spring engaging the tube at a point remote from the terminal portion thereby to tension the fusible section, and an arc suppressing material in said tube.

6. A fuse link comprising a terminal portion, a fusible section, a flexible section, an insulating tube surrounding the fusible section, said tube being engaged with the terminal portion, a helical spring concentrically related to said flexible section and including means connecting one end of said spring and the flexible section, the other end of said spring engaging the tube ata point remote from the terminal portion thereby to tension the fusible section, and a deliquescent material in said tube whereby arc suppressing material will begenerated when the fusible section is severed.

'7. A fuse link having. a terminal section, a separable section, a rigid section, and a. flexible section, in combination with an insulating tube engaged with the terminal section and surrounding the fusible section and at least a portion of the rigid section, and a spring surrounding the rigid section and having one end engaged with the tube remote from the terminal section and the other end engaged with the rigid section, said flexible section being wholly exterior of said tube.

8. A fuse link having a terminal "section, a separable section, a rigid section, and a flexible section, in combination with an insulating tube engaged with the terminal section and surrounding the fusible section and at least a portion of thelrigid section, a spring surrounding the rigid section and having one end engaged with the tube remote from the terminal section and the other end engaged with the rigid section, and an arc suppressing material in the tube.

9. A fuse link having a terminal section, a separable section, a rigid section, and aflexible section, in combination with an insulating tube engaged with the terminal section and surrounding the fusible section and at least a portion of the rigid section, a spring surrounding the rigid section and having one end engaged with the tube remote from the terminal section and the other end engaged with the rigid section, andan arc extinguishing material in the tube, said arc extinguishing material embodying water of crystallization.

10. A fuse link including a terminal section, a fusible section, a flexible section, and tensioning means for the fusible section: said means comprising a spring connected at oneI end with the flexible section, a. tube interposed between the other end of the spring and the terminal section whereby to hold said spring under stress and surrounding the fusible section and at least a ,portion of said spring, and a tube engaging the spring and reciprocal relative to said flexible section.

11. A fuse link comprising a terminal, a fusible section connected to the terminal, a rigid section connected to the fusible section, a flexible section electrically connected With the rigid section, a tube surrounding said fusible section and a portion of said rigid section and engaged with said-terminal, and a spring concentric with the tube and engaged at one end therewith, the other end of the spring being engaged with said rigid section at a point remote from the tube, thereby tensioning said fusible section.

l2. A fuse link comprising a terminal, a fusible section secured to the terminal, a rigid section secured to the fusible section, a tensioning tube engaged with said terminal and enclosing said fusible section, a spring concentric with the rigid section disposed in said tube and engaged with the rigid section and the tensioning tube.

13. A tubular insulating member, contact means closing one end of said member, said member being open at the other end, a contact on said member intermediate the ends thereof, a conductor in said member connecting said contacts, said conductor having a separable portion in said member and a flexible conducting portion extending from the separable portion and from the open end of said member, a tube and a spring, said tube being engaged at one end with said conductor and at a portion remote therefrom with said spring, said spring being engaged with said conductor, whereby to tension said separable portion.

14. The combination with a fuse tube having upper and lower contacts and open at one end, of a fuse link comprising a terminal engaged with the upper contact, a fusible section connected to the terminal, a rigid section connected to the fusible section, a flexible section electrically connected with the rigid section, a second tube surrounding said fusible section and a portion of said rigid section and engaged with said terminal, and a spring concentric with the second tube and engaged at one end therewith, the other end of the spring being engaged with said rigid section at a point remote from the second tube, thereby tensioning said fusible section.

l5. The combination with a fuse tube closed at one end by a contact and open at the other end, of a fuse link in said tube, said fuse link comprising a terminal secured to said contact, a fusible section secured to the terminal, a rigid section secured to the fusible section, a tensioning tube within the first mentioned tube engaged with said terminal and enclosing said fusible section, a spring concentric with the rigid section disposed in said tube and engaged with the rigid section and the tensioning tube.

16. A tubular insulating member, contacts on said tube in spaced relation to each other, a conductor in said member connecting said contacts, said conductor having a separable portion in said member, and a flexible portion, an insulating tube surrounding the separable portion, i

and a spring tensioning said separable portion and disposed wholly within said member, said tube and spring being engaged with each other and with portions of said conductor to tension said separable portion.

17. A tubular insulating member, contact means closing one end of said member, said member being open at the other end, a contact on said member intermediate the ends thereof, a conductor in said member connecting said contacts, said conductor having a separable portion in said member and a flexible conducting portion extending from the separable portion. a tube and a spring, said tube being engaged at one end with said conductor and at a portion remote therefrom with said spring, said spring being engaged with said conductor, whereby to tension said separable portion.

18. A fuse link comprising a terminal section, a fusible section, a ilexible section, and a rigid section connecting the fusible section and the flexible section; in combination with a tube engaging lthe terminal section and surrounding the fusible section and a portion of the rigid section, and a spring engaged at one end with the rigid section and at the other end with the tube, whereby to tension the fusible section.

19. An electrically conducting link including a separable section, a flexible section, and a rigid section connecting the separable section and the flexible section: in combination with a tube surrounding the separable section and a portion of the rigid section, and a spring engaged with the tube at the end remote from the separable section and with the rigid section at a point remote from the tube.

20. A fuse link for expulsion cartridges, said link including a fusible section and a flexible section electrically connected to said fusible section; in combination with a spring concentrically re lated thereto and comprising no portion of the circuit through said link, a tube surrounding the fusible section, and means engaging one end of said tube with one end of said fusible section, a portion of the link intermediate the ends of said tube being held under tension by said spring and by the end of said tube remote from said fusible section, said flexible section extending from said remote end to provide a terminal adapted to extend to the exterior of a cartridge.

2l. A unitary embodiment of a replaceable spring tensioned fuse link for fuse cartridges, said link comprising a terminal portion, a fusible sec tion, and a exible section, all electrically connected in series and in combinationwith an in sulating tube engaging the terminal portion and surrounding the fusible section and a portion of said flexible section, said flexible section extending from said tube and being adapted to extend to the exterior of a cartridge, and a spring in said tube having means engaging one end thereof with the end of the tube remote from said terminal portion, the other end of said spring being engaged with said link at a point intermediate the ends of said tube, said tube holding said spring under tension, whereby said fusible section is placed under tension prior to insertion into a fuse cartridge.

22. A unitary embodiment of a replaceable spring tensioned fuse link for expulsion fuse cartridges, said link comprising a terminal porv tion, a fusible portion, a relatively rigid portion. and a iiexible portion` all electrically connected in series and in combination with an insulating tube engaging said terminal portion and concentrically related to said fusible portion and said rigidy portion, and a spring held under stress between said rigid portion and said tube, whereby said fusible portion is tensioned, the tension on said fusible portion being predetermined before said fuse link is placed in a fuse cartridge, said flexible portion extending from said rigid portion exteriorly of said tube and adapted for extension to the exterior of a cartridge.

23. A unitary fuse link for insertion into standard expulsion fuse cartridges of varying lengths and bores having upper and lower line terminals and open at its lower end, said link comprising a fusible portion, a flexible terminal portion electrically connected with one end of said fusible portion and of a length permitting said flexible portion to extend out from the open end of said expulsion fuse cartridge for connection with the lower line terminal, a secondl terminal engaging portion electrically connected with the opposite end of said fusible portion for connection with the upper line terminal, a tubular member surrounding said fusible portion, means retaining said tubular member in place around said fusible portion prior to rupture thereof, and means applying a tension force to said fusible portion as the parts of said link are assembled into a unitary structure, whereby a quick separation of the fused portion will be obtained when the fuse is blown. 24. Aunitary fuse link for insertion into standard expulsion fuse cartridges of varying lengths and bores having upper and lower line terminals and open at its lower end, vsaid link comprising a fusible portion, a flexible terminal portion electrically connected with one end of said fusible portion and of a length permitting said flexible portion to extend out from the open end of said `expulsion fuse cartridge for connection with the lower line terminal, a second terminal engaging portion electrically connected with the opposite end of said fusible portion forconnection with the upper line terminal, a tubular member surrounding said fusible portion, means retaining said tubular'memberin' place around said fusible portion prior to rupture thereof, and means applying tension to said fusible portion and placing said tubular portion under compression as the component parts of said link are being assembled to form a unitary fuse link.

25. A unitary fuse link for insertion into standard expulsion fuse cartridges of varying lengths andbores having upper and' lower line terminals and open at its lower' end, said link comprising a fusible portion, a flexible terminal portion elec- 4.

trically connected with one end of said fusible portion and of a length permitting said `flexible portion to extend out from the open end of said expulsion fuse cartridge for connection with the lower line terminal, a second terminal engaging portion electrically connected with the opposite end of said fusible portion for connection with the upper line terminal, a tubular member surrounding said fusible portion, means retaining said tubular member in place around said fusible portion prior to rupture thereof, and a coil spring coaxial with said tubular member and co-acting therewith and with said terminal engaging portions to apply a predetermined tension to said 'fusible portion and a compressing force upon said tubular member as the component parts of said link are assembled t6 form a unitary fuse link.

26. A unitary fuse link for insertion into standard expulsion fuse cartridges of varying lengths and bores having upper and lower line terminals and open at its lower end, said link comprising a fusibleportion, a flexible terminal portion elec- ,trically connected with one end of said fusible portion and of a length permitting said flexible portion to extend out from the open end of said expulsion fuse cartridge forccnnection with the4V lower line terminal, a secondA terminal engaging portion electrically connected with the opposite en d of `said fusible portion for connection with the upper line terminal, a tubular member surrounding said fusible portion, means retaining said tubular member in place around said fusible portion prior to rupture thereof, said means comprising a coil spring, a bearing surface upon said second terminal engaging portion for contacting one end of said tubular member, and means coacting with the opposite end portion of said tubular member, whereby a predetermined tension force is'applied by said spring to said fusible portion to insure a quick wide separation of its parts upon rupture thereof, said tubular member acting as a compression member resisting tension force prior to rupture of said fusible portion.

27. As a new article of manufacture a spring tensioned fuse link adapted for insertion into standard expulsion fuse cartridges of varying lengths and bores, said tension being predetermined When the component parts of the link are assembled prior to insertion into said cartridge, said fuse link comprising a fusible section, a flexible conducting leader composed of a relatively large number of `fine wires in parallel electrical conducting relation, means electrically connecting the fusible section and the flexible conducting leader and comprising a section which is less readily fusible than the fusible section and the flexible conducting leader, a tube surrounding the fusible section, and a spring held under tension between said tube and fuse link, at least a portion of said flexible section being disposed exteriorly of said tube whereby to prevent fusing of the flexible conducting leader when tne fusible section has blown.

28.' As a new article of manufacture a spring tensioned fuse link adapted for insertion into standard expulsion fuse cartridges of varying lengths and bores, said tension being predetermined when the component parts of the link are assembled prior to insertion into said cartridge, saidfuse link comprising a fusible section, a flexible conducting leader composed of a relatively largel number of fine wires in parallel electrical conducting relation, means electrically connecting the fusible section and the flexible conducting leader and comprising a section which is less readily fusible than the fusible section and the flexible conducting leader, whereby to prevent fusing of the flexible conducting leadeg` when the fusible section has blown, a spring engaging said means, and spring stressing means providing a predetermined tension force on said fusible section when said elements are assembled for insertion in said cartridges, at least a portion of said leader extending to a point remote from said tending out of the other end of said fuse tube for connection to the other line terminal, fusible means interconnecting said terminals, said conductor being freely movable-out of said fuse tube on blowing of said fusible means, and a coil spring inside said fuse tube and anchored at the other end thereof and arranged to bias said terminals apart.

30. A replaceable fuse link comprising, a fuse tube the inner surface of which is provided with an arc extinguishing material which is adapted under the action of an arc to evolve a gaseous arc extinguishing medium, a pair of relatively infusible terminals one being located at one end of said fuse tube and the other being movably mounted within said fuse tube, a iiexible lead connected to the other of said terminals, fusible means interconnecting said terminals, and spring means biasing said terminals apart.

31. A replaceable fuse link comprising, a fuse tube the inner surface of which is provided with an arc extinguishing material which is adapted under the action of an arcto evolve a gaseous arc extinguishing medium, a pair of relatively infusible terminals one being located at one end of said fuse tube and the other being movably mounted within said fuse tube. a flexible lead connected to the other of said terminals, fusible means interconnecting said terminals, and a spring operatively interconnecting said fuse tube and said fusible means and placing the former in compression and the latter in tension.

32. A renewable fuse link comprising a fuse tube, a first fuse terminal at one end of said fuse tube, a conductor including a second fuse terminal and a flexible lead extending out of the other end of said fuse tube, fusible means interconnecting said fuse terminals, and a spring carried by the link and tensioning said fusible means.

33. A renewable fuse link comprising, a fuse tube, a first relatively inusible terminal at one end of said fuse tube, a second relatively infusible terminal within said fuse tube, a fuse wire interconnecting said terminals, a flexible lead connected to said second terminal and extending out of the other end of said fuse tube, land a coil spring carried by the link and biasing said terminals apart.

34. A renewable fuse link comprising, a fuse tube, a fuse terminal at one end of said fuse tube, a iiexible lead extending out of the other end of said fuse tube, a fusible element interconnecting said fuse terminal and said flexible lead, a spring carried by the link and tensioning said fusible element, and means securing said one end of said fuse tube to said fuse terminal independently of said spring.

35. A fuse link comprising spaced conducting elements, a tubular member supported by one of said elements, an insulating tube supported at least in part by said tubular member, and a iusible element joining said conducting elements located within said tube.

36. As an article of manufacture, a se1f-con tained fuse link comprising a fusible element, a rst terminal for said element comprising a relatively rigid member, a tube of insulation enclosing said element and resting endwise against said rst terminal, anchor means for the remote end of said tube, a iiexible lead having an extension passing through said anchor means and forming a secondterminal for said element, and a spring connected between said anchor means and said second terminal for placing said element under tension.

37. As an article of manufacture, a self-contained fuse link comprising a fusible element, a first terminal for said element comprising a relatively rigid member, a tube of insulation enclosing said element and resting endwise against said rst terminal, anchor means for the remote end of said tube, a flexible lead having an extension passing through said anchor means and forming a second terminal for said elementI and a spring connected between said anchor means and said second terminal for placing said element under tension, said rigid member having means adaptable to clamping means of various forms for anchorage to the terminal at the closed end of a fuse tube.

38. A replaceable fuse link comprising a fuse tube, a terminal at one end of said fuse tube, a iiexible lead extending out of the other end of said fuse tube, a fusible section interconnecting said terminal and said exible lead, a coil spring inside said fuse tube tensioning Said fusible section and compressing said fuse tube, and means substantially uniformly distributing the stress of said spring as applied in compressing said fuse tube.

39. A replaceable fuse link comprising a fuse tube, a terminal at one end of said fuse tube, a conductor extending out of said fuse tube including a terminal and a exible lead connected thereto, a fusible section interconnecting said terminals, a coil spring inside said fuse tube tensioning said fusible section and compressing said fuse tube, and means substantially uniformly distributing the stress of said spring as applied in compressing said fuse tube.

ALWIN G. STEINMAYER,

DISCLAIMER th Milwaukee, Wis. FUSE LINK CONSTRUC- 2,270,225.-Alwn G. Steinmayer, Sou

13, 1942. Disclaimer filed May 4, 1942, by

TION. Patent dated January the assignee, Line Material Company. Hereby enters this disclaimer to claims 12, 13, 14, 15, 16, 17, 18, 21, 22, 23, 24, 25, and 27 to 39, inclusive, of said Letters Patent.

[Oice'al Gazette May 26, 1942.]

DISCLAIMER ilwaukee, Wis. FUsE LINK CONSTRUC- 2,270,225.-Alwn G'. Steinmayer, South M 42. Disclaimer filed May 4, 1942, by

TION. Patent dated January 13, 19 the assignee, Line Material Company. Hereby enters this disclaimer to claims 12, 13,. 14, 15, 16, 17, 18, 21, 22, 23, 24, 25, and 27 to 39, inclusive, of said Letters Patent.

[Oicial Gazette May Q6', 1942.]

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