US3868617A

US3868617A - Latch coupled fuse and exhaust control device

Info

Publication number: US3868617A
Application number: US295825A
Authority: US
Inventors: James W Dragon; Gerald Sakats
Original assignee: S&C Electric Co
Current assignee: S&C Electric Co
Priority date: 1972-10-10
Filing date: 1972-10-10
Publication date: 1975-02-25
Anticipated expiration: 1992-02-25
Also published as: CA977802A

Abstract

The exhaust terminal of an expulsion fuse is telescoped with and latch coupled to an exhaust control device resulting in containment of forces generated on blowing of the fuse between the fuse and the exhaust control device and, in one embodiment, no external application of these forces to the supports for the fuse and exhaust control device.

Description

United States Patent 1191 Dragon et al.

[4 1 Feb. 25, 1975 1 LATCH COUPLED FUSE AND EXHAUST CONTROL DEVICE [75] Inventors: James W. Dragon; Gerald Sakats,

both of Arlington Heights, 111.

[73] Assignee: S & C Electric Company, Chicago,

[22] Filed: Oct. 10, 1972 [21] Appl. No.: 295,825

[52] US. Cl..... 337/203, 337/282 [51] Int. Cl. 'H0lh 39/00 [58] Field of Search 337/275, 279, 280, 281,

[56] References Cited UNITED STATES PATENTS 3,391,368 7/1968 Fahnoe ..337/203 3,513,437 5/1970 McMorris 337/282 X 3,575,682 4/1971 3,575,683 4/1971 3,719,912 3/1973 Harner 337/282 X Primary Examiner-.l. D. Miller Assistant Examiner-Fred E. Bell Attorney, Agent, or Firm-Kirkland & Ellis [57] ABSTRACT The exhaust terminal of an expulsion fuse is telescoped with and latch coupled to an exhaust control device resulting in containment of forces generated on blowing of the fuse between the fuse and the exhaust control device and, in one embodiment, no external application of these forces to the supports for the fuse and exhaust control device.

18 Claims, 15 Drawing Figures PATENTED FEBZS I975 sum 1 a; e

PATENTED FEBZSIBYS sumaufs TO REMOVE FUJE TURN BUSHING 90 THEN PULL PATENTED 3,868,617

sum 5 8f 5 wb lN p SHEET 5 BF 6 PATENTED FEB25 I975 LATCH COUPLED FUSE AND'EXHAUST CONTROLDEVICE This invention is an improvement over the constructions disclosed in Fahnoe US. Pat. Nos. 3,575,682 and- 3,57 5,683,'issued Apr. 10, I971. In the constructions of the above patents an expulsion fuse is mounted in cantilever fashion at one end with the other exhaust end telescoped in a terminalfit ting carried byfan exhaust control device that is stationarily mounted'in a supportstructure; When-the fuse blows, the resulting mechanical forces react endwise of the fuseagainst its support and against the support for the exhaust control device. There is a tendency for the fuse to move away from the exhaust control device haust'control device within the fuse and exhaust control device in-'a new and improved manner; to reduce the weight and required strengths of the mounting components for the expulsion fuse and exhaust control device; to latch the fuse to the exhaust control device on insertion of the former into the latter; toemploy a pair I of leaf springs cooperating with notches in a cylindrical terminal at the discharge end of the fuse for locking it in operative position; to disengage the springs by pivoting the fuse about its longitudinal axis; to provide a locking plate slidable transversely of the fuse for holda portion of an exhaust control device having associated therewith a slide locking plate in'accordance with another embodiment of this invention FIG. 11 is a view, in side elevation, of the construction shown in FIG. 110, the slide locking plate being shown in the unlocked-position.

FIG. '12 is a vertical sectional view taken generally along line. 12-12-of FIG. 11 and at an enlarged, scale, the showing being that with the slide locking plate in the locked position. i

' FIG. 13 is a view, partly in side-elevation and partly I in section, of an expulsion fuse arranged to be held in place by another slide. locking plate.

FIG. 14 is a perspective view. of the slide locking plate shown in FIG. 13.

FIG. 15 is a view, in side elevation, of a pivoted expulsion fuse arranged to be detached from apivot-ally mounted expulsion control device in-accordance with thisinvention. I

Referring now to'FIGS. l to 6- of the drawings it will 'be'observed that the reference character 10 designates,

generally, a fuse drawer that may be slidably mounted in a housing such as that shown in Beebe US. Pat. No. 3,573,561 issued Apr. 6, I971. The fuse drawer lO includes a metallic front panel 11 and extending therefrom are upper and

lowerchannel members

12 and 13.

Vertical support plates 14 extend between the channel I members 1-2 and 13 with insulating barrier plates 15 ing it in operative position on the exhaust control device and for releasing it therefrom; to arrange for the locking plate to have different widths of slots, the larger for receivingthere'through the terminal at the discharge end of the fuse and the smaller having sides to interfit 'with lugs on the terminal to lock the fuse in place; to

mount the fuse in subsurface switchgear and to disengage it exteriorly thereof; and to pivotally mount the exhaust control device and to unlatch the fuse from the exhaust control device when the assembly has been pivoted to an alternate position.

In the drawings:

FIG. 1 is a perspective view of a fuse drawer having fuses mounted thereon in accordance with this invention.

FIG. 2 is a view, partly in side elevation and partly in section of an expulsion fuse illustrated in FIG. 1.

FIG. 3 is a vertical sectional view taken generally along line 3-3 of FIG. 2.

FIG. 4. is a vertical sectional view taken generally along line 4-4-of FIG. 3.

FIG. 5 is a longitudinal sectional view of an expulsion fuse that can be employed in the drawer shown in FIG. 1. 1

FIG. 6 is an end view of the expulsion fuse shown in FIG. 5' looking from right to left, a portion being shown in section. u

FIG. 7 shows diagrammatically how the present invention can be employed in connection with subsurface switchgear.

FIG. 8 is a vertical sectional view through a single phase mounting for an expulsion fuse embodying this invention.

' FIG. 9 is a view, in end elevation and taken generally along line 9-9 of FIG. 8. FIG. 10 is a top plan view of mounted thereon for separating expulsion fuses 16 of which there are three in number for a three phase fuse assembly.

The fuses 16 are of identical construction and, as shown in FIG. 5, each includes a mounting terminal assembly that is indicated, generally, at 17 at one end projects for mounting from which'a threaded stud 18 on a'suitable insulator l9.

As illustrated in FIG. 2 the insulator 19 is pivotally mounted on the fuse panel 11' for movement through an angle of by means of a spacer plate 22 that is located in a circular-opening 23 in the fuse panel 11. Bearing plates 24 on opposite sides of the fuse panel I] and of the spacer plate 22 serve to hold the insulator 19 with the expulsion fuse 16 extending therefrom in proper horizontal aligned relation. Bolts 25 secure a handle 26 to the insulator.l9. The bolts 25 extend through the spacer plate 22 and bearing plates 24 into a suitable metallic fitting at theadjacent end of the insulator 19. The handle 26 is employed for pivoting the insulator l9 and the expulsion fuse 16 mounted thereon between the locked and unlocked positions in a manner to be described.

The end of the expulsion fuse l6 opposite the mounting terminal assembly 17 is provided with a cylindrical exhaust terminal 27 that is arranged to telescope with a sleeve fitting, shown, generally at 28, which is carried by an exhaust control device 29 that may be of the kind and character shown inthe above Fahnoe patents. Also the exhaust control device 29 can be arranged and constructed as disclosed in Harner et al. application Ser. No. 192,238, filed Oct. 26, I971. The expulsion fuse discharges into the exhaust control device 29 through arcuate exhaust openings 30 on opposite sides of a bridge portion 31 which are illustrated in FIG. 6. The exhaust control device 29 is mounted on a suitable insulator 32.

The sleeve fitting 28 comprises a metallic sleeve 34 that is suitably secured, as by welding, to the exhaust control device 29. The sleeve 34 is threaded as indicated at 35 for receiving a contact collar as indicated, generally, at 36 and forms a part of the sleeve fitting 28. The contact collar 36 is arranged to provide good electrical contacting engagement with the exhaust terminal 27.

As pointed out hereinbefore it is desirable to provide for latching the expulsion fuse 16 in place on the exhaust control device 29. Then the endwise reaction incident to blowing of the expulsion fuse 16 is wholly contained in hand in the exhaust control device 29.

For this purpose the exhaust terminal 27 is provided with diammetrically opposite slots 37, as shown in FIG.

5, for receiving leaf springs 38, FIG. 4, which are mounted in cantilever fashion by screws 39 at the ends of transverse slots 40 on the-contact collar 36. When the expulsion fuse l6 blows, it tends to move endwis'e away-from the exhaust control device 29. It is restrained from such movement by engagement with shoulders 41 of the transverse slots 37 by the juxtaposed edges of the leaf springs-38.

In order to stiffen the leaf springs 38 and provide easy entry of, the fuse 16, they are upset as indicated at 42 along one edge. e I

, After the expulsion fuse 16 has blown, it can be withdrawnfrom the sleeve fitting 28 by pivoting it about its longitudinal axisby the handle 26 to bring circular intermediate portions 43 of the exhaust terminal 27 into engagement with the insides of the leaf springs 38. This forces the leaf springs 38 apart and permits endwise movement of the expulsion fuse 16.-

For withdrawing the fuse drawer l0, all'of the handles 26 are pivoted from the latched positions shown in FIG. 1 through 90 to the'unlatched positions. This operation lifts the leaf springs 38 out of the transverse slots 37 and permits opening movement of the fuse drawer l0. The..blown fuse or fuses 16 then can be replaced and the new fuses properly aligned with'the han- I dles 26. Thereafter, with the handles 26 in either the latched or unlatched positions the fuse drawer 10 can be returned to the closed position shown in FIG. 1. If the handles26 are in the latched position when the fuse been pivoted to the unlatched position, it can be withdrawn from the housing 46 and replaced as may be dedrawer 10 is returned to the closed position, then the leaf. springs 38 are separated as the exhaust terminals ground vault in which is located a metallic housing,

shown generally at 46, that is mounted on insulators 47. Bus bars 48 and 49 interconnect the exhaust control device 29 to cable terminators 50 and 51. The expulsion fuse 16 is mounted as described hereinbefore in sleeve fitting 28 for latching engagement with the exhaust control device 29 which is mounted on the insulator 32. The upper end of the expulsion fuse 16 is mounted by an insulator52 having a terminal-rod extending therethrough for engagement by a cable terminator 53 which can be removed, as indicated, to expose a bail 54. After removal of the cable terminator 53by a live line stick 55, the latter can be employed to engage the bail-54 and pivot the expulsion fuse 16 to the u'nlatchedposition. After the expulsion fuse 16 has sired. The withdrawal and application of the expulsion fuse 16 are essentially the same as described hereinbefore but employing the live line tool 55.

In FIGS. 8 and 9 the reference character 58 designates, generally, a single phase fuse assembly in a metallic housing that is indicated, generally, at 59. The housing 59 has a back wall 60 on which the insulator 32 carrying the exhaust control device 29 can be mounted as shown. The housing 59 also includes a front wall 61 on which is mounted a circular plate 62 that may be formed of insulation and removably secured to the front wall 61 by bolts 63. The circular plate 62 is arranged to mount the insulator 19 for pivoting the expulsion fuse 16 about its longitudinal axis for removal from and application-to the sleeve fitting 28 in the manner described hereinbefore. After removal of the bolts 63, the circular plate 62 can be pivoted as illustrated in FIG. 9 in the direction of arrow 64 to unlock the expulsion fuse 16 from the sleeve fitting 28. After it is unlocked, the assembly can be withdrawn and the expulsion fuse .16 replacedon the insulator l9. Thereafter, the assembly can be reinserted in the housing 59.

A bus bar 65 interconnects the exhaust control device 29 and a terminal 66-which is carried by and extends through an insulator 67. I The insulator- 67 is mounted on a circular plate 68 that preferably is nonre'movably mounted by bolts 69 on the front wall 61.

Reference now can be had to FIGS. 10, 11 and 12 of the drawings. In FIG. 10 there is indicated, generally, at 72' an expulsion fuse which is essentially the same as the expulsion fuse 16 referred to hereinbefore and shown particularly in FIG. 5. The expulsion-fuse 72 is provided with an exhaust terminal 73 which is essentially the same as the exhaust terminal 27 described hereinbefore exceptthat, instead of the transverse slots 37 there are provided diaminetrically opposite radially extending locking lugs 74.'These locking lugs 74 are arranged to interfit with a corresponding shaped-recess 75 in a sleeve 76 which forms a part of a sleeve fitting that is indicated, generally, at 77 and corresponds to the sleeve fitting 28 described herein before. It will be understood that the exhaust terminal 73 is cylindrical in configuration except for the locking lugs 74 and that the recess 75has a corresponding configuration. The sleeve 76is externally threaded at 78 for receiving a slide holding collar 79 which has an opening 80 for the cylindrical portion of the exhaust terminal 73 and the locking lugs 74.

For holding the expulsion fuse 72 in place there is provided a slide locking plate that is indicated, generally, at 81. It is moveable in a transverse slot 82 that extends across the sleeve76. The slide locking plate 81 has upturned ends 83 to facilitate shifting it between the locked and unlocked positions. At one end the slide locking plate 81 has an opening 84 for receiving the cylindrical exhaust terminal 73 and the radially projecting locking lugs 74. The opening 84 includes a circular portion 85 arranged 'to clear the cylindrical exhaust terminal 73 and notches 86 for receiving the locking lugs 74.

As shown in FIG. 11 the slide Iockirig plate 81 has a lengthwise extending slot 87 from the opening 84 the width of which is such as to provide clearance between the edges and the surface of the exhaust terminal 73. Inclined edge portions 88 are arranged to bear against the'locking lugs 74 when the slide locking plate 81 occupies the position shown in FIG. 12 which is to the left of that shown in FIG. 11, and illustrated by broken lines in FIG. 10. Not only do the inclined edge portions 88 bear wedgingly against the locking lugs 74 to hold the expulsion fuse 72 securely in place but also they provide good electrical contact engagement between the exhaust terminal 73 and the sleeve 76.

FIGS. 13 and 14 illustrate a further embodiment of the invention which is somewhat similar to that illustrated in FIGS. 10, 11 and 12. In FIG. 13 a sleeve 90 is secured to the exhaust control device 29 and is provided with-a thread 92 for receiving a slide holding collar 93 which, together with the sleeve 90 provides a sleeve fitting that is indicated, generally, at 91. The slide holding collar 93 has a transverse slot 94 for receiving a slide locking plate that is indicated, generally, at 95. The slide locking plate 95 has a longitudinally extending slot 96 with one end 97 being relatively narrow and having a width corresponding to the diameter of the cylindrical portion of the exhaust terminal 73 associated therewith. The slot 96 also has a relatively wide portion 98 for receiving the locking lugs 74 when the slide locking plate 95 is in the unlocked position or a position to the right of that shown in FIG. 13. An inclined surface 99 on the under side of the slidelocking plate 95 is arranged to cooperate with the transverse slot 94 for applying pressure to the locking lugs 74 to securely hold the expulsion fuse 72 in place and provide a good electrical connection and seal between the exhaust terminal 73 and the sleeve fitting 91. A transverse bar 100, which is added after the slide locking plate 95 has been inserted in the transverse slot '94, serves to limit the movement of the slide locking plate 95in the unlocking direction.

The products incident to blowing of the expulsion fuse 72 are received by an exhaust product deflector 101 in the exhaust control device 29 and thereby directed at right angles to the longitudinal axis of the expulsion fuse 72. Thus, the endwise force applied to the expulsion fuse 71 is completely absorbed by the exhaust control device 29. In turn, because the deflector 101 redirectsthat endwise force in equal and opposite directions, there are no net external forces applied to the mounting components for the fuse 72 and the exhaust control device 29, for example to the

insulators

19 and 32, FIG. 1, other than the weight of the fuse 72 and of the exhaust control device 29. This results in a reduction in the required thickness or strength and the volume of the enclosure in which this combination is mounted. Essentially then, except for the weight of the expulsion fuse 72 and of the exhaust control device 27, they can be suspended in space without mechanical support because of the elimination of external transverse forces incident to the blowing of the expulsion fuse 72. The exhaust products are directed to flow through metallic heat absorbent material 102 and pellets of activated alumina 103 where they are largely absorbed and reduced. Final exhaust is through filter plugs, one of which is shown at 103', as described in more detail in the Harner et al application above referred to. v

Referring now particularly to FIG. of the drawings it will be observed that reference character 104 designates, generally, a metallic housing provided with upper and

lower insulators

105 and 106. A plate 107 extends horizontally'from the upper end of the lower insulator 106 and carries a pivot support 108 for receiving trunions 109 that extend from opposites sides of an exhaust control device 110 which is essentially the same as the exhaust control device 29 referred to hereinbefore. An expulsion fuse 111, similar to the expulsion fuses 16 and 72, is telescoped in a sleeve fitting that isindicated, generally, at 112 and is similar to the sleeve fitting 77. A slide locking plate, indicated generally at 113, is arranged to detachably secure the expulsion fuse 111 to the sleeve fitting 112. The slide locking plate 113 has an integral hook 114 to receive the live line stick for unlatching the expulsion fuse 111 from the sleeve fitting 112. At its lower end the expulsion fuse 111 has an exhaust terminal 115 which is essentially the same as the

exhaust terminals

27 and 73 referred to hereinbefore.

At its upper end the expulsion fuse 111 has a contact 116 that is arranged to engage a stationary contact 117 which is carried by the upper insulator 105. When the expulsion fuse 111 is in the upright position a circuit is completed between the horizontal plate 107 on the lower insulator 106 and the stationary contact 117 carried by the upper insulator 105.

After the expulsion fuse 111 has been unlatched from the exhaust control device 110 by operation of the slide locking plate 113 through the agency of the live line stick 55, the latter can be applied, asshown by broken lines, to an eye 118 that extends from the contact 116. The expulsion fuse 11 then can be pivoted about the trunions 109 to the broken line position where it can be lifted out of the sleeve fitting 112 for replacement as will be understood readily.

We claim:

1. A circuit interrupter comprising an expulsion fuse having a longitudinal axis and having an exhaust terminal at one end, an exhaust control device at said one end of said expulsion fuse, and a latch means for mechanically interconnecting said exhaust terminal and said exhaust control device, and for disconnecting said exhaust terminal and said exhaust control device in response to pivotal movement of said fuse about its longitudinal axis by an angle of less than 360.

2. The circuit interrupter according to claim 1, further comprising mounting means for mounting said expulsion fuse for pivotal movement about its longitudinal axis.

3. The circuit interrupter according to claim 1 wherein said latch means includes a leaf spring on said exhaust control device extending transversely of said expulsion fuse for sidewise engagement with one side of a transverse slot on said exhaust terminal.

4. The circuit interrupter according to claim 1 wherein said latch means includes a pair of cantilever springs on said exhaust control device on opposite sides and extending transversely of said exhaust terminal for sidewise engagement with one side of transverse slots in said exhaust terminal.

5. The circuit interrupter according to claim 2 wherein said mounting means comprises an insulator connected to the other end of said expulsion fuse, and manually operable means carried by said insulator for causing pivotal movement of said fuse.

6. The circuit interrupter according to claim 5 wherein said mounting means mounts said expulsion fuse in a housing with said exhaust control device at one end and said insulator extending to the opposite end, and said manually operable means is adapted to 7 receive a live line tool for pivoting said expulsion fuse and removing said fuse from said housing.

7. The circuit interrupter according to. claim wherein said manually operable meansfurther comprises a plate secured to said insulator for pivoting said expulsion fuse to disconnect said latch means, and removable means for securing said plate to said insulator.

8. A circuit interrupter comprising an expulsion fuse having an exhaust terminal at one end, an exhaust control device at said one end of said expulsion fuse, and latch means including a slide locking plate means for being moved in a first direction transversely of said expulsion fuse for mechanically interconnecting said exhaust terminal and said exhaust control device, and for being moved in a second direction transversely of said expulsion fuse for mechanically disconnecting said exhaust terminal and said exhaust control device.

9. The circuit interrupter according to claim 8 wherein said exhaust terminal comprises radially extending locking lugs, and said exhaust control device comprises a sleeve fitting for telescopic engagement by said exhaust terminal, and said slide. locking plate means is movable through said sleeve fitting into and out of overlying relation to said locking lugs.

10. The circuit interrupter according to claim 9 wherein said sleeve fitting includes a threaded sleeve secured to said housing, and a collar means threaded on said sleeve for locking engagement with said slide locking plate means.

11. The circuit interrupter according to claim 10 wherein said slide locking plate means has an elongated opening with notches for receiving said exhaust terminal and said locking lugs therethrough in the unlocked position of said slide locking plate, and said collar wherein said slide locking plate means includes rib means for applying-locking pressure to said locking lugs. v

13. The circuit interrupter according to claim 8 wherein a threaded sleeve is secured to said exhaust control device having an opening therethrough for receiving the discharge from said expulsion fuse, a collar is threaded on said sleeve and has a transverse slot, said exhaust terminal is provided with'radially extending locking lugs and has telescopic engagement with said collar, and said slide locking plate means is movable through said transverse slot in said collar into and out of overlying relation to said locking lugs.

14. The circuit interrupter according to claim 13 wherein said slide locking plate means has a longitudinal slot that is relatively narrow at one end with sides for overlying said'lugs and is relatively wide at the other end for receiving said lugs therethrough.

15. The circuit interrupter according to claim 14 wherein saidslide locking plate means has an inclined surface on one side for cooperation with said transverse slot in said collar to apply locking pressure to said locking lugs.

16. The circuit interrupter according to claim 8 wherein means pivotally mount said exhaust control device, said slide locking plate has means for connecat one end, an exha'ust control device extending transversely of said expulsion fuse, and latch means for mechanically interconnecting said expulsion fuse and said exhaust control device, and for disconnecting said expulsion fuse and saidexhaust control device in response to pivotal movement of said expulsion fuse about its longitudinal axis by an angle less than 360.

18. The circuit interrupter according to claim 17 wherein said exhaust control device includes means for directing the exhaust products and forces from said expulsion fuse in substantially equal and opposite directions and transversely of said expulsion fuse whereby there are substantially no external forces generated on blowing of said expulsion fuse.

Claims

1. A circuit interrupter comprising an expulSion fuse having a longitudinal axis and having an exhaust terminal at one end, an exhaust control device at said one end of said expulsion fuse, and a latch means for mechanically interconnecting said exhaust terminal and said exhaust control device, and for disconnecting said exhaust terminal and said exhaust control device in response to pivotal movement of said fuse about its longitudinal axis by an angle of less than 360*.

6. The circuit interrupter according to claim 5 wherein said mounting means mounts said expulsion fuse in a housing with said exhaust control device at one end and said insulator extending to the opposite end, and said manually operable means is adapted to receive a live line tool for pivoting said expulsion fuse and removing said fuse from said housing.

7. The circuit interrupter according to claim 5 wherein said manually operable means further comprises a plate secured to said insulator for pivoting said expulsion fuse to disconnect said latch means, and removable means for securing said plate to said insulator.

9. The circuit interrupter according to claim 8 wherein said exhaust terminal comprises radially extending locking lugs, and said exhaust control device comprises a sleeve fitting for telescopic engagement by said exhaust terminal, and said slide locking plate means is movable through said sleeve fitting into and out of overlying relation to said locking lugs.

11. The circuit interrupter according to claim 10 wherein said slide locking plate means has an elongated opening with notches for receiving said exhaust terminal and said locking lugs therethrough in the unlocked position of said slide locking plate, and said collar means has an elongated opening with notches for receiving said exhaust terminal and said locking lugs therethrough.

12. The circuit interrupter according to claim 11 wherein said slide locking plate means includes rib means for applying locking pressure to said locking lugs.

13. The circuit interrupter according to claim 8 wherein a threaded sleeve is secured to said exhaust control device having an opening therethrough for receiving the discharge from said expulsion fuse, a collar is threaded on said sleeve and has a transverse slot, said exhaust terminal is proviDed with radially extending locking lugs and has telescopic engagement with said collar, and said slide locking plate means is movable through said transverse slot in said collar into and out of overlying relation to said locking lugs.

14. The circuit interrupter according to claim 13 wherein said slide locking plate means has a longitudinal slot that is relatively narrow at one end with sides for overlying said lugs and is relatively wide at the other end for receiving said lugs therethrough.

15. The circuit interrupter according to claim 14 wherein said slide locking plate means has an inclined surface on one side for cooperation with said transverse slot in said collar to apply locking pressure to said locking lugs.

16. The circuit interrupter according to claim 8 wherein means pivotally mount said exhaust control device, said slide locking plate has means for connection to a live line tool, a contact is mounted on the other end of said expulsion fuse, and a stationary contact is arranged to be engaged by said fuse contact.

17. A circuit interrupter comprising an expulsion fuse having a longitudinal axis arranged to exhaust only at one end, an exhaust control device extending transversely of said expulsion fuse, and latch means for mechanically interconnecting said expulsion fuse and said exhaust control device, and for disconnecting said expulsion fuse and said exhaust control device in response to pivotal movement of said expulsion fuse about its longitudinal axis by an angle less than 360*.