US2358684A

US2358684A - Flip-out device for fuses

Info

Publication number: US2358684A
Application number: US454924A
Authority: US
Inventors: Chester W Brown
Original assignee: Line Material Co
Current assignee: Line Material Co
Priority date: 1942-08-15
Filing date: 1942-08-15
Publication date: 1944-09-19
Anticipated expiration: 1961-09-19

Description

p 19, 1944- c. w. BROWN 2,358,684

FLIP-OUT DEVICE FOR FUSES Filed Aug. 15, 1942 2 Sheets-Sheet l l 5 52; 2 22%, 22,, :22 Vl-t l 1 1 1 lll nwa V m Sept. 19, 1944. c. w. BROWN FLIP-OUT DEVICE FOR FUSES Filed Aug. 15, 1942 2 Sheets-Sheet 2 INVENTOR.

Z I v aw/ ,0 0 fi w I III! I I- L 1 I 1 I I Iii... I

Patented Sept. 19, 1944 FLIP-OUT DEVICE FOR FUSES Chester W. Brown, Milwaukee, Wis., assignor to Line Material Company, Milwaukee, Wis., a corporation of Delaware Application August 15, 1942; Serial No. 454,924

14 Claims.

This invention pertains to fuse cut-outs and has to do more especially with a device commonly known as a flip-out which is operative, immediately after the blowing of a fuse and in response thereto, quickly to separate the arc electrodes within the fuse cartridge and, preferably, to wholly expel from the open end of the cartridge the elongate conductive leader constituting a severed part of the fuse link.

- The purpose underlying the use of such devices is to ensure extinguishment of the are within the fuse cartridge when the blow-out is caused by a fault current of such little amperage that the ensuing explosion is not, amply forceful to expel the leader or to bring about a sufficient separation of the arc electrodes within the cartridge.

Modern dropout fuses are furnished factoryequipped with flip-outs which function as above indicated; and the same is true with respect to some fuse cut-outs of the non-dropout type. But there are in use a great many fuse cut-outs of the simple expulsion non-dropout type which are not equipped with in-built flip-outs, and it is to the equipping of the latter that the present invention is more particularly addressed.

The primary object of the present invention is to provide an inexpensive flip-out which can be utilized as an accessory to an expulsion fuse cutout not otherwise so equipped.

Another and related object is to provide an accessory of the aforementioned'character which can easily and quickly be installed in the field. Still another object is to provide a simple flipout which is inherently operative, when properly installed, to apply a uniform predetermined tension to the fuse-link-which tension is determined at the factory and not dependent upon the linemans judgment.

The unique features which characterize this invention can most readily be adduced in conjunction with the detailed description of the two preferred embodiments illustrated in the accompanying drawings, wherein:

Fig. 1- is a longitudinal sectional view of one form of flip-out device constituting a preferred embodiment of the invention.

Fig. 2 is a longitudinal sectional view of a fuse cartridge of the expulsion type shown equipped with the flip-out device of Fig. 1.

Fig. 3' is an elevational view, partly in section, of the lower end of the fuse cartridge of Fig. 2, illustrating the manner of operation of the flipout device of Fig. 1 in response to blowing of the fuse.

includes an elongate tube Fig. 4 is a longitudinal sectional view of an alternative flip-out device representing a second preferred embodiment of the invention.

Fig. 5 is a longitudinal sectional view of a fuse cartridge of the expulsion type, showing the flip-out device of Fig. being inserted.

Fig. 6 is an elevational view, partly in section, of the lower end of the fuse cartridge of Fig. 5, illustrating the flip-out device of Fig. 4 installed and ready to operate when the fuse blows.

I shall describe first the showing of Figs. 1, 2, and 3 and thereafter the showing of Figs. 4, 5, and 6.

The expulsion fuse cartridge of Figs. 2 and 3 I!) which may be of horn fiber or Bakelite lined with fiber or otherwise in accordance with well-known practices. Tube H] has a bore l0 and is threaded externally at its upper end to accommodate a tubular metal ferrule H, which is threaded at l2 to receive a removable metal cap I3.

diameter of adapter 25 Gripped between cap [3 and the top of ferrule II is a button-head contact member M which forms an integral part of the upper terminal I5 of a conventional strain-type fuse-link IS. The fuse-link includes a fusible section ll, connected at its upper end to upper terminal I5 and at its lower end to a long flexible conductive leader l8 which extends downwardly through bore l0 and upwardly from the bottom end of tube ID to a binding-post terminal l9, which includes a metal sleeve 20 and clamping screw 2|. Sleeve 20 embraces tube l0 and is secured thereto by a pin 22.

The flip-out device, identified as a whole by reference numeral 23,is shown, in Fig. 2, installed in the fuse tube and is separately illustrated in Fig. 1. It comprises an elongate flexible shaft 24 consisting of a close-wound wire helix, anadapter 25 threaded to the upper end of the flexible shaft, a helical spring 26 telescopically surrounding and co-axial with the flexible shaft and secured at its upper end to the adapter, a disc-like nut 21 threaded to the lower end of the spring, and a second disc-like nut 28 threaded to the lower end of the flexible shaft. The inside diameter of flexible shaft 24 is such as to fit freely or, in any event, to permit insertion therethrough of flexible leader 18. It is not necessarily a close fit for the leader althoughit is so illustrated in Fig. 2. The outside should, preferably, be a fuse tube, but it may be all, so long as it clears free running fit in the a loose fit or no fit at the bore.

instantly without hindrance. aration is effected between the arcing electrodes To install the flip-out the flexible leader is threaded through the bore of the flexible shaft and the latter, together with the adapter and attached spring 26 is inserted in the open end of the fuse tube; and the spring is stretched and thus put under tension by pushing on the exposed end of the flexible shaft and on nut 28. This results in seating nut 21 against the end of the fuse tube, with nut 28 hearing against nut 2'|all as clearly illustrated in Fig. 2. The flexible leader, being pulled taut, is secured at its free end to terminal I9 and it serves to anchor the flip-out in place and to retain it under tension as will be evident from an inspection of Fig. 2.

The flexible shaft, while capable of being easily flexed in response to a laterally applied force, has the inherent property of being very resistant to buckling when operating as a column. For

that reason the shaft will always remain erect against the tension of spring 26.

The tension of spring 26 is applied through the flexible shaft and nut 28 to flexible leader I8 and thus normally maintains the fuse-link under considerable tension-which tension is of definite amount, predetermined at the factory and governable by appropriate selection of spring 25 or by appropriately varying the length of the flexible shaft, or both.

When fusible section II blows, the flexible leader is .no longer capable of restraining the flip-out and, in consequence, the leader is quickly expelledfrom the fuse tube by'the downward movement of the flexible shaft and nut 28which, of course, is brought about by the contraction of spring 26.

If flexible shaft 24 were not laterally yieldable it is not improbable that the flip-out would be arrested in its action by the flexible leaderdue to the abrupt bend in the leader where it emerges from the fuse tube and turns upwardly.

But the shaft being quite flexible in response to laterally directed force is, capable of bending in the manner illustrated inFig. 3 whereby to permit the inside end of theleader to move down within the cartridge andv the arc is quickly extinguished, regardless of Whether or not the accompanying explosionis sufficiently forceful to accomplish the same end without theaid of the flip-out.

That part of the flip-out device which in Fig.

'3 is shown still within the fuse tube either drops,

out by gravity or is knocked out by the momentum of the downwardly moving flexible shaft.

No doubt both are contributing factors.

In the alternative embodiment of Figs. 4, 5, and 6 the fuse cartridge is identical with that of Fig. 2 and bears the same reference numerals. The flip-out device is shown in detail in Fig. 4 and comprises a tubular metal sleeve 29, ahelical spring 30,- and a metal ferrule 3|. Sleeve 29 is internally threaded at by secured to the upper end of spring 39. Ferrule 3| is internally threaded to receive the lower end of the spring. .Sleeve 29 is frustro-conically flanged at its lower end to form a head 29a which serves to limit the extent to which the sleeve can be inserted into the fuse tube; and ferrule 3| is formed with a .frustro-conical skirt designed to fit within the tapered concavityof head 29a, as shown in Fig. 6.

Thus a quick sep-' its upper endand there-.

In Fig. 5, sleeve 29 is shown pushed all the way?" into the fuse tube to the full extent that head 29a is compressing spring 30; and flexible leader l8 has i been pulled taut and anchored to terminal I9. When so anchored, the leader functions to hold spring 30 under compression.

The curled peripheral edge on head 29a provides a suitable surface about which to bend, without crimping, the flexible leader, and the frustrO-conically flared skirt on ferrule 3| affords an angular surface over which the flexible leader can slide, and it avoids sharp turns which might tend to impede rapid movement of the spring and ferrule along the leader when a blowout occurs.

It will be apparent that the flip-out of Figs. 4, 5, and 6 operates according to the same principle as that of Figs. 1, 2, and 3 previously described. But here it is the spring rather than its companion member that is first ejected when a blow-out occurs. 7 I

The flip-out of Figs. 4, 5, and 6 comprises fewer parts-than that of Figs. 1, 2, and 3'; but, on the other hand, sleeve 29 entails more costly tooling than any of the parts of the first-described device.

It will be self-evident that each of the two above-described flip-out devices can easily be installed by a lineman in the field, and that each is quite inexpensive to manufacture and, therefore, can be replaced at trifling cost if lost as a result of a fuse blowout. Moreover, it will be apparent that the tension applied to the fuse-link by the flip-out is determined independently of the linemans judgment-it being essential only that the device be correctly installed, which doesnot entail the exercise 'of discretionary judgment on the linemans part. .The\tension can be determined at the factory consonantly with the rating of thefuse-link, and flip-outs of different tensions can, if desired, be furnished to suit the, various fuse-link sizes.

What is claimed is: v 1. A flip-out device comprising, in combination: a helical compression 'spring, a rigid, tu-

bular sleeve telescopically encircling'and co-axial with said spring, one end only of said sleeve being frustro-conically flanged exteriorly, the periphwithin the frustro-conical concavity of' said.

flange when said spring is compressed and'there- .by to limit the deflection of said spring compressively. V

2. A fuse linkflipout device for use in an'expulsion type fuse tube, said device comprising outer and inner telescopically related tubular members, one end of said outer member being anchored to the corresponding end of said inner member, the opposite ends of said members being free for relative axial movement, at least one of said members including a spring and being expansible axially of the other member, said other member being undeformable lengthwise as a result of stressing of said spring including member axially, the inner of said members providing an can bore 'therethrough and the outercf said members having anchoring means at its free end.

--'3'. A fuse link flipout device for use in an expulsion type'iuse tube, said device comprising a movement, said spring member being deformable 'axially' 'and thus effective to apply lengthwise fst'ress't'osaid tubular member, one of said memhere being provided with an axial bore therethrough and the other member having anchoring means at its free end.

4. A fuse link flipout device for use in an expulsion type fuse tube, said device comprising a tubular elongated flexible shaft, a helical spring telescopically and coaxially related to said shaft, one end of said shaft being connected to a corresponding end of said spring, the opposite ends of said shaft and spring being free for relative movement axially of said shaft, and anchoring means on the free end of said spring.

5. A fuse link flipout device for use in expulsion type fuse tubes, said device comprising a tubular elongated flexible shaft consisting of a close-wound Wire helix, a helical spring telescopically related to and encircling said shaft, one end of said shaft being connected with a corresponding end of said spring, the opposite ends of said shaft and spring being free for relative movement, said spring being resiliently expansible lengthwise of said shaft, and anchoring means attached to the free end of said spring.

6. A fuse link flipout device for use in an expulsion type fuse tube, said device comprising a tubular elongated flexible shaft consisting of a close-wound wire helix, a helical tension spring telescopically related to and encircling said shaft, an adapter securing one end of said shaft to a corresponding end of said spring, the opposite ends of said shaft and spring being free for relative movement, said spring being resiliently expansible lengthwise and axially of said shaft, a nut attached to the free end of said spring, and a nut attached to the free end of said shaft, said nuts being engageable upon expansion of said spring to limit the extent of relative movement of said free ends in one direction.

'7. A fuse link flipout device for use in an expulsion type fuse tube, said device comprising a helical compression spring and a rigid tubular sleeve telescopically encircling said spring, one end of said sleeve being anchored to a corresponding end of said spring, the opposite ends of said spring and sleeve being free for relative movement, the free end of said sleeve being enlarged diametrically to serve as anchor means.

8. A fuse link flipout device for use in an expulsion type fuse tube, said device comprising a helical compression spring, a rigid tubular sleeve telescopically encircling said spring, one end of said tube being anchored to a corresponding end of said sprin and the other end being frustoconically flanged exteriorly and free for movement relative to said spring.

9. In combination with a fuse including a fuse tube open at one end, a pair of terminals one terminal being adjacent said open end, and a fuse link in said tube connecting said terminal and having a portion projecting from said end and anchored to said one terminal; of a flipout device removably positioned in said tube comprising outer and inner telescopically related tubular members disposed in the open end of said tube, the ends of said members most remote from said open'end being anchored together, at least one of saidmembers including a spring and being expansible axially of the other member, the inner member providing an axial bore through which saidlfuse link extends, and the outer member having anchoring means engaging the open end of said tube, said fuse link normally holding said spring under stress, whereby upon rupture of said link it will be expelled from said tube.-

lO; Incombination with'a fuse including a fuse tube open at one end, a pair of terminals one .terminal beingadjacent said open end, and a fuse link in'said tube connecting said terminal and having a portion projecting fromsaidopen end and anchored to said one terminal; of a flipout device removably positioned on said tube comprising a tubular member and a helical spring member which are telescopically related and disposed in the open end of said tube, the ends of said members most remot from said open end being anchored together, the opposite ends of said members being free for relative movement, the inner member of said device having an axial bore through which said fuse link extends, and the outer member having anchoring means engaging the open end of said tube, said fuse link normally holding said spring under stress, whereby upon rupture of said link it will b expelled from said tube.

11. In combination with a fuse including a fuse tube open at one end, a pair of terminals one terminal being adjacent said open end, and a fuse link connecting said terminals and having a portion anchored to said one terminal; of a flipout device removably positioned in said tube comprising a tubular elongated flexible shaft loosely embracing said fuse link, a helical tension spring telescopically and coaxially related to said shaft, an adapter securing one end of said shaft to a corresponding end of said spring, the opposite corresponding ends of said shaft and spring being relatively movable, and an anchoring nut on the relatively movable end of said spring engaging the open end of said tube, said spring being expanded lengthwise and axially of said shaft and normally maintained expanded by said fuse link acting through said shaft.

12. In combination with a fuse including a fuse tube open at one end, a pair of terminals one terminal being adjacent said open end, and a fuse link connecting said terminals and having a portion anchored to said one terminal; of a flipout device removably positioned in the open end of said tube and comprising a helical compressing spring loosely embracing said fuse link, and a rigid tubular sleeve telescopically encircling said spring, the end of said sleeve most remote from said open end being anchored to the corresponding end of said spring, the other end of said sleeve being enlarged diametrically and engaged with the open end of said tube, said spring being normally held under compression by said link and sleeve.

13. In combination with a fuse including a fuse tube open at one end, a pair of terminals one terminal being adjacent said open end, and a fuse link in said tube connecting said terminals and anchored to said one terminal; of a flipout device removably positioned in said tube comprising a helical compression sprin loosely surrounding said fuse link, a rigid tubular sleeve telescopically encircling said spring, the end of said sleeve most remote from said open end being anchored to the corresponding end of said spring and the other end being irusto-conicallyrfiared diametricallyv toward, the corresponding end of said spring, said flared end engaging said open end of said tube, and a frusto-conically flared ferrule secured to said spring, said fuse link normally-holding said ferrule nested insaid flared end of said sleeve and said spring'under compression.

- 14.. In combination with a' fuse including a fuse tube open at one end, a pair of terminals one or which is adjacent said open end, and a fuse link in said tube connecting said terminals and anchored to said one terminal; of a fiipout .device removably positioned in said tube comprising a tubular elongated flexible shaft consisting said other end of said helix and engageable with said anchoring nut for limiting the extent to which said spring may be expanded, said fuse link normally acting through said helix to hold said spring expanded.

CHESTER W; BROWN.