US2347641A - Fuse construction - Google Patents

Description

May 2, 1944 A. RAMsEY 2,347,641

FUSE CONSTRUCTION May 2, 1944- A. RAMsEY FUSE CONSTRUCTION Filed Jan. 29, 1942 3 Sheets-Sheet 3 head 3| is provided on the upper end of the rodlike terminal III and securely holds the rod-like apertured, as indicated 4terminal 30 ln the aperture 2B when the cap 23 is screwed tightly into place.

The construction of the inner fuse tube 22 is similar to that of the outer fuse tube or housing 2|. At its upper end the inner fuse tube 22 is provided with a ferrule 32 that is threaded on a suitable snap ring 33 located in a peripheral groove in the inner fuse tube 22. Snap ring 33 is provided with a shoulder 34 on its under side for engaging the inwardly projecting shoulder 35 of the Ierrule 24 at the lower end of the outer fuse tube or housing 2| for limiting the outward movement of the inner fuse tube 22. The snap ring 33 is located in such position on the inner fuse tube 22 that, when the shoulder 34 thereof engages the inwardly projecting shoulder 35 of the ferrule 24, the lower end of the rod-like terminal 30 still projects into the bore of the liner 23. In this position the upper end of this 4bore is substantially closed and the building up of high gas pressure in the outer fuse tube or housing 2| is prevented.

With a view to biasing the inner fuse tube 22 outwardly with respect to the outer fuse tube or housing 2|, .a coiled compression spring 36 is interposed between the inner end of the fuse tube 22 and the under side ci' the upper fuse terminal 26 that closes the upper end of the outer fuse tube or housing 2|. It will be observed that the spring 36 bears generally against the ferrule 32 rather than against the upper end of the inner fuse tube 22 itself. This construction prevents abrasion of the upper end of the inner fuse tube 22. It is desirable that the spring 36 be held in the upper closed end of the outer fuse tube or housing 2| when the inner fuse tube 22 moves downwardly. For this purpose the upper end turns of the spring 36 are threaded past the inwardly extending ears 31 of a washer 3B that is clamped between the under side of the upper fuse terminal 26 and the upper end of the outer fuse tube or housing 2|. Y

The fuse tube or housing 2| and the inner fuse tube 22 are prevented under the influence of the 36 by a fuse link, shown generally at 4U, and positioned adjacent the lower open end of the inner fuse tube 22 which, it will be understood, forms an are chamber lined with a. material capable of evolving an arc extinguishing medium, i. e., the fiber liner 23. The fuse link 4D is of the replaceable type. It is provided at its upper end with a fuse link terminal 4| having a stud 42 coil compression spring which is that of the stock from which the terminal is machined and underneath it there is a knurle'd portion 44 for receiving a sleeve 45, preferably formed of liber, and preventing rotation thereof relative to the iuse link terminal 4|. The lower end 46 of the link terminal 4| is deformed onto the upper ends of strain and fusible elements 41 and 48. The strain element 41 is preferably formed of a high strength wire, such as Nichrome, while the fusible element 48 is preferably formed of silver. A sleeve 49 of suitable insulation may be positioned, as shown. around the strain element 41, if desired, to prevent the fusible element 43 from coming into contact engagement therewith. The fuse link 4|) is provided with a lower fuse link terminal 50, the upper end 5| of which is deformed onto the lower ends of the strain and fusible elements 41 and 43. The fuse link terminal 50 is provided with a peripheral groove 52 in which is .positioned a snap ring 53 for preventing the sleeve 45 from slipping out of position over the terminal 50. The lower end 54 of the fuse link terminal 50 is deformed onto a flexible conductor 55 that is formed by a large number of strands of fine wire and which is provided with a cone terminal56 deformed thereon intermediate its ends. The lower fuse link terminal 50 will be free to move out of the lower end of the arcing chamber within the fuse tube 22 under the expulsion action of the blast of arc extinguishing medium on blowing of the strain and fusible elements 41 and 43. When this occurs the arc is drawn between the lower end of the rod-like terminal 30 and a lower fuse terminal 51 that is carried by and is movable with the inner fuse tube 22. It will be observed that the cone terminal 56 constitutes an anchor means for the lower end of the fuse link 40 and that it is positioned between ears 58 that are integrally formed with the rearwardly extending portion 59 of the lower fuse terminal 51. It will be observed that the lower fuse terminal 51 is threaded on a suitable split ring 60 that is located in a peripheral groove adjacent the lower end of the inner fuse tube 22. The vided by the flexible conductor 55 between the lower link terminal 50 and the lower fuse terminal 51 insures conjoint movement of these terminals and separation of the former from the rod-like stationary terminal 30.

As illustrated, the lower fuse terminal 51 is Iprovided with an aperture 6| which leaves the bore of the liner 23l and the inner fuse tube 22 open and through which the ilexible conductor 55 extends. By leaving the lower end of the inner fuse tube 22 open, the products of the arc formed on blowing of the fuse link 40 can readily escape and dangerous pressures are not built up within the fuse device Il, as might otherwise be the case if both ends of it were closed.

to Figure 2 of the drawings, that the upper circuit terbifurcated support member In order to mount the fuse device in place.

as shown in Figure 2,

stood. As shown more clearly in Figure 3 of the drawings the outer end portions 10 of the rigid wires B4 are flared outwardly and portions 1| are mechanical interconnection pro` constructed as illustrated in my Patent No. 2,144,707. Also. the spring fuse link construction shown inthe copending application oi' Hugh A. Triplett, Serial No. 758,372, filed December 20,

1934, can be used it desired. The fuse link |28 includes a cone terminal |29 which is arranged to intert with the bifurcated end o! a foot portion |30 integrally formed with the lower ruse terminal |00.

When the fuse link |28 blows. the coil compression spring |2| is no longer restrained, and it promptly moves the inner fuse tube I down.. wardly until it and the lower fuse terminal |03 occupy the positions shown by the broken lines in Figure 5 or the drawings. The uppermost turn of the spring |2| is expanded so that it :dts snugly within the upper terminal |82 and thereby is held in place after the fuse link |28 blows. It will be observed that the ribs |08 maintain contact engagement with the outer end portions |08 of the lower circuit terminal while the inner fuse tube ||1 is moving through a substantial distance. Before separation takes place from the lower circuit terminal the arc incident to the blowingof the fuse link |28 will in most cases have been extinguished so that no arcing occurs between the ribs |08 and the lower circuit terminal.

As illustrated in Figure 5 of the drawings the cover is provided with an integrally formed eye |3| to facilitate handling of the cover.

When the housing 85 is mounted in a substantially vertical position as illustrated in Figure of the drawings, it is desirable that the cover ||0 remain substantially as shown so as to yiully close the front side of the housing 85. For this purpose the outer ends of the arms 98 forming the U-shaped combination support and contact member are provided with contact shoes |32 as shown in Figure 6 of the drawings. These contact shoes |32 are so shaped as to cooperate with the upper fuse terminal |02 and through the biasing force of the upper circuit terminal act to retain the upper fuse terminal |02 and hence the cover ||0 in the position shown. However, on the application of sufllcient force to the eye |3|, it is possible to spread the contact shoes |32 against the biasing action of the upper circuit terminal provided by the arms 93 and 99 so as to permit the removal of the cover ||0 and associated fuse tube ll'for replacing a blown fuse link |28.

As shown in Figure 7 of the drawings, the inward movement of the cover ||0 is limited by bosses |38 integrally formed with the side Walls 8'| of the housing or box 85. This then insures that the ribs |08 will be properly placed with respect to the inturned ends |06 of 'the lower circuit terminal so as to provide good contact en gagement therebetween.

,'In Figure 8 of the drawings there is shown an alternate form of lower fuse terminal construction. As shown, at the lower end of the inner fuse tube there may be provided a lower fuse terminal |38 having integrally formed ribs, one of which is indicated at |39 to provide contact engagement with the lower circuit terminal while the fuse tube is moving downwardly. A foot portion |40 is integrally formed with the lower fuse terminal |38 and its lower end is bifurcated for receiving a cone terminal |4| of a replaceable fuse link |42. A stud |43 is integrally formed with the lower fuse tube terminal |38 and on it is threaded a clamp nut |44 for clamping the end of the flexible lead |45 of the fuse link |42.

In the event that it is desired to mount the housing 88 in the position shown in Figure 10 of the drawings so as to more widely separate the lower fuse terminal from the lower circuit terminal, the contact shoes |32 are reversed from their positions shown in Figure 6 to the positions shownA in Figure 9 of the drawings. When so located theresilient force of the upper circuit terminal acting through the arms 98 and 83 tends to bias the terminal |02 and the door ||0 outwardly so that, after the ribs |08 or |33 have moved out oi latching engagement with the cooperating lower circuit terminal, the cover ||0 and inner fuse tube carried thereby can swing to the position shown in Figure 10 of the drawings.

For mounting the housing in the position shown in Figure 10 of the drawings an angle bracket |50'can be provided, as shown. The angle bracket |50 can be secured to a suitable clamp |5| which, as shown, is arranged to mount the assembly on a cross-arm |52.

In Figures 11 and 12 there is shown an alternate iorm of lower fuse terminal construction. Instead of integrally forming'a foot portion |30 with the terminal |09, as shown in Figure 5 and described hereinbefore, a terminal |09 is provided the upper portion of which is the same as the terminal |09. However, a foot portion |54 is pivoted at |55 onto the lower end of the terminal |09 as shown. This foot portion |54 carries a slotted opening |58 for receiving the cone terminal |23 of the fuse link |28, If desired a threaded stud and clamp nut can be used for securing the ilexible lead to the foot portion |54, as shown in Figure 8. The flexible lead can also be passed over the foot portion |54 and secured to the terminal |09' by suitable means, such as a threaded stud and clamp nut as shown in Figure 8. This construction permits direct expulsion of the cone terminal |29 and associated parts of thefuse link |28 since they are maintained in alinement with the bore of theinner fuse tube and do not extend over an edge thereof.

When the fuse link |28 blows, the resulting blast aided by gravity causes the foot portion |54 to swing to the position shown in Figure 12 so as to provide a more free .discharge from the fuse tube The force causing the foot portion |54 to swing to the position shown in Figure 12 can be augmented by a suitable spring.

Since certain further changes can be made in the foregong constructions and diiferent embodiments of the invention can be made Without departing from the spirit or scope thereof, it is intended that all matters contained in the above description or shown in the accompanying drawings shall be considered as illustrative and not in a limiting sense.

I claim as my invention: y

l. Circuit interrupting means comprising, in combination, a first circuit terminal having a first support means extending therefrom the outer end oi which is biiurcated and hook-shaped vopening upwardly, a second circuit terminal having a second support means extending therefrom the outer end of which is bifurcated and hook-shaped opening inwardly, a first fuse tube, a second fuse tube telescoped with said iirst fuse tube, a first fuse terminal closing one end of said iirst fuse tube and having a pair of oppositely extending arms for mounting in said upwardly opening hook-shaped end of said rst support means, a second terminal at one end of said second fuse tube but leaving the same open, said second terminal having a pair of oppositely extending ribs for mounting in said inwardly opening hook-shapedend of said second support means, said fuse tubes being biased apart, and a conductor including a fusible section interconnecting said first and second fuse terminals A and restraining said fuse tubes from movement apart as long as said fusible section remains intact, said second terminal on blowing of said fusible section moving out of engagement with said second support means and said first terminal rotating in said first support means with said fuse tubes, whereby an air gap is formed between said second terminal and said second support means.

2. Circuit interrupting Ameans comprising, in combination, a rst circuit terminal having a first support means extending therefrom the outer end of which is bifurcated and hook-shaped opening upwardly, a second circuit terminal having a second support means extending therefrom the outer end of which is bifurcated and hook-shaped opening. inwardly, a first fuse tube, a second fuse tube telescoped with said first fuse tube, a first fuse terminal closing one end of said rst fuse tube and having a pair of oppositely extending arms for mounting in said upwardly opening hookshaped end of said first support means, means on said first fuse terminal intertting with said first support means and arranged and adapted to prevent separation thereof except when the former is moved to a predetermined position relative to the latter, a second terminal at one end of said second fuse tube but leaving the same open, said second terminal having a pair of oppositely extending ribs for mounting in said inwardly opening hook-shaped end of said second support means, said fuse tubes being biased apart, and a conductor including a fusible section interconnecting said first and second fuse terminals and restraining said fuse tubes from movement apart as long as said fusible section remains intact, said second terminal on blowing of said fusible section moving out of engagement with said second support means and said rst terminal rotating in said first support means with said fuse tubes, whereby an air gap is formed between said second terminal and said second support means.

3. Circuit interrupting means comprising, in combination, a first circuit terminal, support means associated with said terminal, a second circuit terminal below said first circuit terminal, retaining means associated with said second circuit terminal, the outer end of said retaining means being bifurcated and hook-shaped opening inwardly, a housing, a fuse tube telescoped with said housing, a first fuse terminal carried by said housing at its upper end for engaging said first circuit terminal, means carried by said housing for pivotally supporting the same on said support means, a second fuse terminal at the lower end of said fuse tube for engaging said second circuit terminal, means projecting from opposite sides of said fuse tube adjacent said lower end thereof for engaging said bifurcated hook-shaped outer end of said retaining means, said fuse tube being biased downwardly with respect to said housing, and a conductor including a fusible section interconnecting said first and second fuse terminals and restraining downward movement of said fuse tube as long as said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving out of engagement with said second circuit terminal whereby an air gap is provided therebetween.

4. Circuit interrupting means comprising, in combination, a rst circuit terminal, support means associated with said terminal, a second circuit terminal below said mst circuit terminal,

retaining means associated with said second circuit terminal, the outer end of said retaining means being bifurcated and hook-shaped opening inwardly, a housing, a fuse tube telescoped with said housing, a first fuse terminal carried by said housing at its upper end for engaging said rst circuit terminal, means carried by said housing for pivotally supporting the same on said support means, a second fuse terminal at the lower end of said fuse tube for engaging said second circuit' terminal, means projecting from opposite sides of said fuse tube adjacent said lower end thereof for engaging said bifurcated hook-shaped outer end of said retaining means, said fuse tube being biased downwardly with respect to said housing, a conductor including a fusible section interconnecting said rst and second fuse ter,- minals and restraining downward movement of said fuse tube as long as said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving out of engagement with said second circuit terminal whereby an air gap is'provided therebetween, and contact means associated with said second fuse terminal for maintaining contact engagement with said second circuit terminal while the former is moving relative toV the latter through a substantial distance.

5. Circuit interrupting means comprising, in combination, a first circuit terminal, support means associated with said terminal, a second circuit terminal below said first circuit terminal, retaining means associated with said second circuit terminal, the outer end of said retaining means being bifurcated and hook-shaped opening inwardly, a housing, a fuse tube telescoped with said housing, a first fuse terminal carried by said housing at its upper end for engaging said first circuit terminal, means carried by said housing for pivotally supporting the same on said support means, a second fuse terminal at the lower end of said fuse tube for engaging said second circuit terminal, means projecting from opposite sides of said fuse tube adjacent said lower end thereof for engaging .said bifurcated hook-shaped outer end of said retaining means, said fuse tube being biased downwardly with respect to said housing, a conductor including a fusible section interconnecting said first, and second fuse terminals and restraining downward movement of said fuse tube as long as said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving out of engagement' with said second circuit terminal whereby an air gap is provided therebetween, and clamp means on said secondfuse terminal for connecting one end of said conductor thereto.

6. Circuit interrupting means comprising, in combination, a first circuit terminal, support means associated with said terminal, a second circuit terminal below said iirst circuit terminal, retaining means associated with said second circuit terminal, the outer end of said retaining means being bifurcated and hook-shaped opening inwardly, a housing, a fuse tube telescoped with said housing, a first fuse terminal carried by said housing at its upper end for engaging said first circuit terminal, means carried by said housing for pivotally supporting the same on said support means, a second fuse terminal at the lower end of said fuse tube for engaging said second circuit terminal including a portion fast on said fuse tube and a. foot portion hingedly mounted thereon and disposed in line with the bore of said -retaining means, said fuse tube being biaseddownwardly with respect to said housing, and a conductor including a fusible section interconnecting said nrst and second fuse terminals and restraining downward movement of said fuse tube as long as said fusible section remains intact, one end of said conductor engaging said hinged foot portion and holding the same in alinement with said bore as long as said fusible section nmains intact, said second fuse terminal on blowing of said fusible section moving out of engagement with said second circuit terminal whereby an air gap is provided therebetween.

7. Circuit interrupting means comprising, in combination, a first circuit terminal having a nrst support means'extending therefrom the outer end of which is bifurcated and hook-shaped opening upwardly, a second circuit terminal having a second support means extending therefrom the outer end of which is bifurcated and hookshaped opening inwardly, a housing, a ilrst fuse terminal on said housing having a pair of' oppositely extending arms for mounting in said upwardly opening hook-shaped end of said first support means, a fuse tube telescoped with said housing a second fuse terminal at the lower end of said fuse tube, said second terminal having a pair of oppositely extending ribs adapted to be received in said bifurcated inwardly opening hook-shaped end of said second support means and providing electrical connection to said second circuit terminal, said fuse tube being biased downwardly with.respect to said housing, and a conductor including a fusible section interconnecting said first and second fuse terminals and restraining downward movement of said fuse tube as long as said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving out of engagement with said second support means whereby an air gap is provided therebetween.

8. Circuit interrupting means comprising, in combination, a first circuit terminal, support means associated with said terminal, a second circuit terminal below said rst circuit terminal, retaining means associated with said second circuit terminal, the outer end of said retaining means being bifurcated and hook-shaped opening inwardly, a housing, a fuse tube telescoped with said housing, a irst fuse terminal carried by said housing at its upper end for engaging said first circuit terminal, means carried by said housing for pivotally supporting the same on said support means, second fuse terminal at the lower end of said fuse tube for engaging said second circuit terminal, means projecting from opposite sides of said fuse tube adjacent said lower end thereof for engaging said bifurcated hook-shaped outer end of said retaining means, a coil compression spring biasing said fuse tube downwardly with respect to said housing. and a conductor including a fusible section interconnecting said iirst and second fuse terminals and restraining downward movement of said fuse tube as long as said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving out of engagement with said second circuit terminal whereby an air gap is provided therebetween.

9. Circuit interrupting means comprising, in combination, a first circuit terminal, support means associated with said terminal, a second circuit terminal below said first circuit terminal, retaining means associated with said second circuit terminal, the outer end of raid retaining means being birturcated and hook-shaped opening inwardly, a housing, a fuse tube telescoped with said housinslga first fuse terminal carried by said housing at its upper end for engaging saidflrst circuit terminal, means carried by said housing for pivotally supporting the same on said support means, a second fuse terminal at the lower end of said fuse tube for engaging said second circuit terminal, means projecting from opposite sides of said fuse tube adjacent said lower end thereof for engaging said bifurcated hook-shaped outer end of said retaining means, a coil compression spring within said housing biasing said fuse tube downwardly with respect to said housing, stop means limiting the downward movement of said fuse tube relative to said housing, and a conductor including a fusible section interconnecting said first and second fuse terminals and restraining downward movement of said fuse tube as long, as said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving'out of engagement with said second circuit terminal whereby an air gap is provided therebetween.

l0. Circuit interrupting means comprising in combination, a first circuit terminal having a ilrst support means extending therefrom the outer end of which is bifurcated and hookshaped opening upwardly, a second circuit terminal having a second support means extending therefrom the outer end of which is bifurcated and hook-shaped opening inwardly, a housing, a first fuse terminal on said housing having a pair of oppositely extending arms for mounting in said upwardly opening hook-shaped end of said first support means, a fuse tube telescoped with said housing, a second fuse terminal at the lower end of said fuse tube, said second terminal having a pair of oppositely extending ribs adapted to be received in said bifurcated inwardly opening hook-shaped end of said second support means and providing electrical connection to said second circuit terminal, a coil compression spring biasing said fuse tube downwardly with respect to said housing, and a conductor including a fusible section interconnecting said rst and second fuse terminals and restraining downward movement of said fuse tube as long as said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving out of engagement with said second support means whereby an air gap is provided therebetween.

11. Circuit interrupting means comprising, in combination, a first circuit terminal having a first support means extending therefrom the outer end of which is bifurcated and hookshaped opening upwardly, a second circuit terminal having a second support means extending therefrom the outer end of which is bifurcated and hook-shaped opening inwardly, a housing, a first fuse terminal on said housing having a pair of oppositely extending arms for mounting in said upwardly opening hook-shaped end of said first support means, a fuse tube telescoped with said housing, a second fuse terminal at the lower end of said fuse tube, said second terminal having a pair of oppositely extending ribs adapted to be received in said bifurcated inwardly opening hook-shaped end of said second support means and providing electrical connection to said said fusible section remains intact, said second fuse terminal on blowing of said fusible section moving out oi' engagement with said second support means whereby an air gap is provided therebetween.

12. Circuit interrupting means comprising, in combination, an insulating housing having rear, top and side walls and open at the front, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, and an .insulating cover for closing said front oi said housing and having means integrally formed therewith for slidably supporting both ends of said fuse tube and guiding the same, one of said fuse terminals for said fuse device'being ixed to-said cover and the other being xed to and movable with said fuse tube away fr'om said one fuse terminal, said fuse tube being restrained from movement by said fuse link and being biased for movement relative to said cover when said fuse link blows.

13. Circuit ,interrupting means comprising, in combination. an insulating housing having rear, top and side walls and open at the front, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, an insulating cover for closing said front of said housing and having means integrally formed therewith for slidably supporting both ends of said fuse tube and guiding the same, one of said fuse terminals for said fuse device being xed to said cover and the other being iixed to and movable with said fuse tube away from said one fuse terminal, said fuse tube being restrained from movement by said fuse link and being biased for movement relative to said cover when said fuse link blows, and means for limiting the movement of said fuse tube relative to said cover after blowing of said fuse link.

14. Circuit interrupting means comprising. in combination, an insulating housing having rear,

top and side walls and open at the front, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, and an insulating cover for closing said front of said housing and having a sleeve portion integrally formed therewith and extending over a substantial portion of the inner side thereof for slidably supportingboth ends of said fuse tube and guiding the same, one of said fuse terminals for said fuse device being fixed to said cover and the other being xed to and movable with said fuse tube away from said one fuse terminal, said fuse tube being restrained from movement by said fuse link and being biased for movement relative 'to said cover when'said :use link blows.

15. Circuit interrupting means comprising, in combination, an insulating housing having rear, top and side walls and open at the front, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and incluaing a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, an insulating cover for closing said front of said housing and having means integrally formed therewith for slidably supporting both ends of said fuse tube and guiding the same, one of said fuse terminals for said fuse device being iixed to said cover and the other being xed to and movable with said fuse tube away trom said one fuse terminal, and spring means `biasing said fuse tube downwardly with respect to said cover, the downward movement of said fuse tube being restrained by said'tuselink. y

16. Circuit interrupting means comprising, in combination, an insulating housing having rear, top and side walls and open at the front, circuit terminals carried by said housing one above the other. and a fuse device for interconnecting said circuit terminals having iuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, an insu lating cover for closing said front of said housing and having means integrally formed therewith for slidably supporting both ends of said fuse tube and guiding the same, one ot said fuse terminals for said fuse device being fixed to said cover and the other being ilxed to and movable with said fuse tube away from said one fuse terminal, spring means biasing said fuse tube downwardly with respect to said cover, the downward movement of said fuse tube being restrained by said fuse link, and means for stopping the downward movement of said fuse tube relative to said cover when the former has reached a predetermined position relative to the latter.

17. Circuit interrupting means comprising, in combination, an insulating housing having rear, top and side walls and open at the frbnt, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, an insulating cover for closing said front oi' said housing and having means integrally formed therewith for slidably supporting both ends o1 said fuse tube and guiding the same, one of said fuse terminals for said fuse device being ixed to said cover and the other being ilxed to and movable with said fuse tube away from said one fuse terminal, and coil compression spring means reacting between said cover and said fuse tube for biasing the latter' downwardly with respect to the former, the downward movement of said fuse tube being restrained by said i'use link.

18. Circuit interrupting means comprising, in combination, an insulating housing having rear, top and also walls and open at the front, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a ruse link for interconnecting said fuse terminals, an insulating cover for closing said front of said housing and having .a sleeve portion integrally formed therewith and extending over a substantial portion of the inner side thereof for slidably supporting both ends of said fuse tube and guiding the same, one oi.' said fuse terminals for said fuse device being fixed to said cover and the other being iixed to and movable with said fuse tube away from said one fuse terminal, and spring means biasing said fuse tube downwardly with respect to said cover, the downward movement of said fuse tube being restrained by said fuse link.

19. Circuit interrupting means comprising, in combination, an insulating housing having rear, top and side walls and open at the front, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, an insulating cover for closing said front of said housing and having a sleeve portion integrally formed therewith and extending over a substantial portion of the inner side thereof for slidably supporting both ends of said fuse tube and guiding the same, one o1' said fuse terminals for said fuse device being nxed to said cover and the other being iixed to and movable with said fuse tube away from said one fuse terminal, and coil compression spring means reacting between said cover and said fuse tube for biasing the latter downwardly with respect to the former, the downward movement of said fuse tube being restrained by said fuse link.

20. Circuit interrupting means comprising, in combination, an insulagng housing having rear, top and side walls and open at the front, circuit terminals carried by said housing one above the other, and a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, and an insulating cover for closing said front of said housing and having means integrally formed therewith for slidably supporting said fuse tube and guiding the same, the upper of said fuse terminals being supported on and carried by said cover, the lower of said fuse terminals being 'supported on and carried by said fuse tube.

21. Circuit interrupting means comprising, in combination, upper and lower circuit terminals, insulating means supporting said circuit terminals in spaced relation one directly above the other, a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse linir` for interconnecting said fuse terminals, said fuse tube being biased to slide downwardly and restrained by said fuse link, means pivotally mounting said fuse device adjacent said upper circuit terminal, and means associated with said upper circuit terminal and cooperating with the fuse terminal engaged therewith for retaining said iluseA device in position thereon after blowing o! said fuse link and downward movement of said fuse'tube.

22. Circuit interrupting means comprising, in

- combination, upper and lower circuit terminals,

insulating means supporting said circuit terminals in oilset relation in the same vertical'plane with respect to each other, a fuse device for interconnecting said circuit terminals having fuse terminals at its ends for engaging said circuit terminals and including a fuse tube adapted to receive a fuse link for interconnecting said fuse terminals, said fuse tube being biased to slide downwardly and restrained by said fuse link, means pivotally mounting said fuse device adjacent said upper circuit terminal and permitting the same to swing under the iniluence of gravity away from said lower circuit terminal on blowing of said fuse link, and means associated with said upper circuit terminal and cooperating with the fuse terminal engaged therewith for urging said fuse device to swing outwardly on blowing of said fuse link.

ALLAN RAMSEY.

Images