US2088152A - Fuse disconnect switch - Google Patents

Description

July 27, 1937. a. L. CARLISLE FUSE DISCONNECT SWITCH Filed March 13, 1955 4 Sheets-Sheet l July 27, 1937. a. L. CARLISLE 2,088,152

FUSE DISCONNECT SWITCH Filed March 13, 1955 4 Sheets-Sheet 2 y 1937- a. L. CARLISLE 2,088,152

FUSE DI SCONNEC'I' SWITCH Filed March 13, 1935 4 Sheets-Sheet s y 1937- a. CARLISLE 2,088,152,

FUSE DISCONNECT SWITCH Filed March 13, 1955 4 Sheets-Sheet 4 UNITED STATES PATENT OFFICE;

2,088,152 FUSE mscoNNEc'r swrrcn George L. Carlisle, Greensburg, Pa., assignor to Railway & Industrial Engineering Co., Greensburg, Pa., a corporation of Pennsylvania Application March 13, 1935, Serial No.'10,949 In Canada February 2, 1934 43 Claims.

This invention relates to fused disconnect switches, and more particularly to combination devices in which the fuse and switch blade comprise a single assembly.

The fuses and fused disconnect switches employed on high potential lines have usually followed the general design of small cartridge fuses. A common construction has been an expulsion tube having end conductive sleeves to which the fuse wire was secured, one sleeve having trunnionsfor seating in a pair of hooked terminal arms while the other sleeve had opposite flat or curved faces that were received between a pair of spring clamping fingers.

The contact areas at the ends of the fuse or fused switch were usually of substantial size, of the order of one or more square inches, and the contact resistance was usually of uncertain magnitude and frequently was relatively high.

Objects of the present invention areto provide simple and rugged circuit breakers of the fuse and/or fused disconnect switch type in which the fuse assembly is yieldingly held between two terminals by pressure exerted substantially axially of the fuse element, and in which the contact areasat one or at both ends of the fuse element are of the order of line or point contacts.

A further object is to provide a fused switch including an expulsion tube having end contacts adapted to be received in appropriate spaced terminals, a wire extending through the tube, and an explosive charge formoving said wire out of the expulsion tube when an overload occurs.

A further object is to provide a fused -disconnect switch in which a pivoted fuse assembly is normally held in approximately vertical position by thepointcontact engagement of the relatively movable end of the fuse assembly with a pair of spring rods Or-terminal members.

other specific object is to provide a fused disconnect switch of the enclosed type in which the fuse element is mounted on the door of a fuse box, and in which the fuse assembly is so constructed that the door drops to open position when the fuse blows.

More particularly, objects are to provide fused disconnect v switches having the properties as above specified, and in which the fuse element is not subjected to strain to retain the fused switch assembly in operative position. These and other objects and advantages of the invention will be apparent from the following specification when taken with the accompanying drawings, in which:

Fig. 1 is a side view of one embodiment of the invention;

Fig. 2 is a front elevation of the same;

3 Figs. 3 and 4 are enlarged side views of the upper end of the switch blade assembly and the contact horn;

Fig. 5 isan enlarged side elevation of the lower terminal and of the lower or pivoted end of the switch blade assembly;

' Fig. 6 is a vertical section through-an enclosed fused switch embodying the invention; 1

Fig. '7 is a fragmentary section showing the latching terminal and latch in the opening position;

Fig. 8 is a side elevation of the assembly;

Fig. 9 is an inside view of the door and fuse assembly;

Fig. 10' is a front view, with parts in section, of the fuse box;

Figs-11 and 12 are sections on lines l Ill and The upper terminal strap 3 clamps a contact horn to the top of the insulator I, the horn comprising a resilient rod 5 in the form of a loop which is reversely bent intermediate its ends to provide a resilient downwardly opening seat B for the reception of the switch blade, and. which terminates in an upwardly turned end I. The inner ends of the horn loop are rigidly clamped by the strap 3, and the sides of the loop are spaced apart horizontally to engage lugs on the fuse assembly. The lower terminal 4 includes a pair of spaced arms which terminate in hooks 8, the mouth of each hook being of less width than the diameter of the alined circular openings through the arms.

The insulator and itsterminal members will be recognized as constituting a mounting for a fuse cartridge or a switch blade. A switch blade pivotally supported on the hooks 8 will be re- ,tained in closed position by the, engagement of appropriate lugs with the latch portion 6 of the contact horn, or a fuse cartridge may be supported between thecontact horn and the hooks 8. In accordance with the invention, a switch blade assembly having the general form of an expulsion fuse is pivotally supported on the hooks 8 and is yieldingly latched to the contact horn. Under normal conditions, the assembly serves as a disconnect switch and, in the case of an overload, the reaction due to the blowing of the fuse releases the blade assembly from the latch and the assembly drops to open position.

The switch blade assembly comprises an elongated expulsion tube 9 of insulating material to which upper and lower collars In, H are secured. A cover 12 is hinged to the upper collar III by a pin I3, and is provided with a leaf spring N that slides over a projection 15 on the collar III to latch the cover in closed position. The pivot I3 is spaced a substantial distance from the axis of the tube 9, and, at a somewhat shorter distance from that axis, the cover I2 is provided with a pair of lugs 16 for engagement in the latch seat 6 of the contact horn. A rib or fin l6 projects upwardly between the lugs IE to form a guide which centers the upper end of the fuse assembly between the spaced rod members 5 on which the seat 8 is formed. A ring I! is formed on the collar 10 at the side opposite the pivot pin l3 and latching lugs Hi.

The lower collar II has a pair of trunnions l8 that are cut away, at opposite sides, to permit the trunnions to pass into the openings of hooks B. A ring l9 at the inner side of the collar H has a bolt and a wing nut 20 at its upper surface, and the outer portions of the ring are preferably grooved to form a shallow seat.

The fuse element of the disconnect switch passes through the expulsion tube 9, its upper end being held against the upper collar ID by a boss 2| on the cover l2, and its lower end being clamped to the lower collar by the wing nut 20. The fuse element is preferably of the explosive type, and may take the form of a small cartridge housing an explosive charge 22 through which an ignition wire 23 passes, one end of the ignition wire being soldered to the conducting base 24 of the shell 24' and the other end being soldered to. a conducting wire 25 which has a length somewhat greater than that of the expulsion tube.

The explosive and the wires are retained in place by appropriate packing such as a wad 26 and wax 21. The explosive charge may be black powder or smokeless powder and the ignition wire 23 may be a resistance wire, of nickel, nichrome or the like, which is raised to the ignition temperature of the explosive, but not volatilized, by current flow in excess of the rated capacity of the fuse. Alternatively, the wire 23 may be of a relatively soft metal whichwill be volatilized, upon an excessive flow of current, at a temperature substantially below the ignition point of the explosive. When the wire 23 is of this latter type, the fusion of the wire opens a gap in the conductive circuit and the resulting arc ignites the explosive charge.

Reverting to Fig. 1 which shows the switch in normal closed position, it will be noted that the latch seat 6 of the contact hook projects beyond the hooks 3 in which the lower end of the fused blade is pivoted, and that the spring pressure exerted upon the cover l2 holds the cover in closed position since the latching lugs it are nearer the axis of the tube 9 than the pivot I3 of the cover l2. The blade assembly is yieldingly retained in the illustrated inclined position by the spring pressure of the contact hook, and the switch may be opened and closed in the usual manner by inserting the hook of a fuse puller or switch operator in the upper ring l1,

Good electrical contacts between the blade assembly and the terminal members are provided by the point contact engagements between the lugs IE on the cover and the round rods which form the seat 6. At the lower end of the assembly, the trunnions I8 may be given a slightly greater curvature than that of the journals in the hooks 8 to provide line contact engagement. Both the upper and the lower contact surfaces are self-cleaning since the cooperating parts wipe across each other when the fuse assembly is turned upwardly into operative position.

In the event of an overload, the wire 23 is heated to ignition temperature by the excessive current flow, thus igniting the explosive charge. The circuit is broken adjacent the upper end of the tube 9 and the high pressure within the tube quickly extinguishes any arc and blows the wire 23 from the tube. The recoil of the explosion tilts the cover l2 about its pivot l3, and this action carries the pivot pin 13 away from the insulator i as the latching lugs it rock on the seat 6. The effect of this angular movement of the cover I2 is to increase the distance from the lugs [6 to the axis of the tube 8 and, when that distance exceeds the spacing of pivot l3 from the axis, the spring pressure on lugs l6 and gravity both operate to drop the blade assembly to open position, as shown in 'dotted lines in Fig. 1.

The blade assembly may then be removed by inserting a fuse puller in the ring l9 and lifting the trunnions l8 out of the hooks 8. The old fuse cartridge is removed, and. a new one in serted, the wire 25 being passed through the tube 9, around the grooved seat in ring ill, and secured to the lower collar by the wing nut 20. The assembly is then returned to the hooks B, and the fused switch is closed by inserting a fuse puller in hook I! and rotating the unit to engage the lugs IS in the seat ii of the contact hook.

The casing 30 of the enclosed i'used switch or cutout shown in Figs. 6 to 14 is formed, as is customary, of a ceramic or other insulating material, and the mounting strap 30' is preferably so shaped that the casing has a slight forward inclination to facilitate the automatic opening of the cover 3! when the fuse blows. One or both side walls of the casing are provided with hooded openings 32 for the introduction of the wires which are to be secured to the upper and lower terminals of the fused switch.

The upper terminal comprises a substantially rigid casting of approximately U-iorm, the central portion 33 of the casting being rigidly bolted to the back wall of the casing and the spaced legs 34 of the casting terminate in notched ends that provide downwardly opening seats 35, the upper ends 36 of the terminal legs being forwardlyinclined to guide the end of a fuse assembly into the seats.

The lower terminal is also of approximately U-shape and has a central section 31 which is rigidly secured, at its upper end, to a plate 38 of bronze or other appropriate resilient material, and a stud bolt 39 passes through the spring plate 38 and lower portion ll] of the terminal to mount these parts on the back wall of the casing. The nut M is not drawn down tightly on bolt 39 and the adjacent portion 40 of the terminal is convex, thus permitting a limited rocking movement of the terminal upon the bolt. The side arms of the terminal 42 are deeply notched by arcuate slots 43 to provide a pivotal seat for the fuse ,assembly. Both terminals are provided with tubular portions 44 into which screws 45 extend to clamp the conductors to the terminals. A name plate 48 may be secured to the lower terminal.

The door 3i has an integral pull ring and is preferably formed of a molded synthetic resin, the inner face of the door being deeply grooved to provide a recess, between the opposed flanges 41, in which the expulsion tube 48 is mounted. The upper conductive collar 49 is fixed to the tube 48 and has lugs 50 which are fixed to flanges 4'! by screws. The inner side of collar 49 has a pair of ears 5| in which the cover 52 is pivotally mounted, the cover having a latch pin or crossbar 53 which engages in the seat 35 of the upper terminal to retain the door in closed position so long as the cover 52 is closed upon the upper end of the expulsion tube.

The lower' conducting member is an arcuate strap 54 which is bolted to the cover 3| and has extensions or hubs 55 for pivotally mounting the door and fuse assembly in the journal slots 43 of the lower terminal. The strap carries a. bolt and wing nut 56 for clamping the lower end ofthe removable fuse to the strap. A washer having'an extension 51 is preferably provided to prevent any loosening of this clamped connection, the extension being received between spaced ears on the lower face of the strap. The fuse is preferably of the cartridge type, as described in detail in connection with Fig. 3.

As in the construction illustrated in Figs. 1 to 5 the pivotal axis of the cover 52 of the fuse assembly is so positioned, with respect to the latch pin 53 and the hubs 55, that pressure exerted along the plane passing through these parts tends to hold the cover in closed position. The spacing "of the terminal seats is slightly less than the distance from the lower face of hubs 55 to the upper face of the latch pin 53when the cover is closed.

The lower terminal is therefore rocked downward, against the force of the spring plate 38. when the door 3| is moved into closed position. The door may be readily closed, however, by a quick upward swing about the hubs 55, and the spring plate 38 then yieldingly locks the door in closed position. A

When the fuse blows, the pressure within the expulsion tube 48 rocks the cover 52 into open position, as shown in Fig. '7, and this movement carries the pivot point of the cover through a plane which extends through the latch seats 35 and the journal slots 43, thus allowing themomentarily increased stress in the spring plate 38 to cooperate with gravity to force the door 3i into open position. The dotted lines in Fig. 6 illustrate the door in an intermediate position but it will be understood that the door swings into a vertical position when fully open. To refuse the device, the door is lifted from the lower terminal, the broken fuse wire and the cartridge are removed, and the new fuse cartridge is inserted without removing the expulsion-tube from the. door.

The contact surfaces of the conducting members on the expulsion tube and on the terminals may be machined to somewhat different curva tures to provide line contact engagements. The door and fuse assembly constitute the blade member of a fused switch since the door may be lower terminals.

The explosive fuse element presents the decided advantage that the circuit is positively opened in a period which is substantially independent of the relative magnitude of the overload. With the usual expulsion fuses employing a'soft metal wire, a slight overload may melt the wire but will fail to open the circuit if metal vapors are evolved at such slow rate that the arc is not extinguished, Such arcing within the tube may be followed by current leakage along the inner wall of the tube and the proposed use of a special non-conducting coating on the tube wall has not proved en-- tirely satisfactory. It is to be understood, however, that soft metal wire fuses may. be used in the novel fused disconnect switch when the load on the protected line is of such a nature that any overload that may be anticipated will be of such magnitude as to eifect a rapid vaporization of a substantial part of the fused wire.

Particular attention is directed to thefact that the invention provides a drop-out fuse in which the fuse element is not subjected to any mechanical stress. Since the retention of the expulsion tube and fuse element in the supporting terminals places no stress upon the fuse element,

there is no change in the electrical properties of the fuse element during the useful life of the fuse. This feature is of particular importance when the fuse element is formed of a relatively soft metal.

This application is a continuation-in-part of my copending application Ser. No. 634,071, 'iiled Sept. 20, 1932. Claims specific to the enclosed type of cutout, as illustrated in Figs. 6 to 14, have been presented in a divisional application, Ser. No. 125,503, filed Feb. 13, 1937.

While I have described preferred embodiments of the invention, it is' to be understood that changes may be made in the several parts and in their relative size, shape and location, without departure from the spirit of my invention, as set forth in the following claims.

I claim:

1. A circuit breaker comprising a pair of .vertically spaced terminals having seat-defining portions presented towards each other, one of said terminals including resilient means integral with the seat-defining portion thereof for yieldingly urging the seat defining portions of said terminals towards each other, an elongated blade member having a conductive member at its lower end for engaging the seat-defining portion of said lower terminal to support the said blade member thereon, a conductive member at the upper end of said blade member and spaced from the lower conductive member to produce a pressure substantially along the elongated blade member when the second conductive member is manually forced into wedging engagement with the seat-defining portion of said upper terminal, and means supporting one of said conductive members and said blade member for relative movement, thereby to facilitate the removal of the blade member from the upper terminal.

2. In a circuit breaker, the combination with a pair of vertically spaced terminal members, a single insulator and means securing integral portions of'the respective terminal members to the opposite ends therebf, and spring means yieldingly urging a portion of the upper terminal member towards the lower terminal member, of a fuse assembly comprising an elongated expul sion tube having a pair of axially spaced conductive members, a fuse extending through said tube and electrically connected between said conductive members, means for engaging the conductive members of the fuse assembly with the said terminal members and with said spring means exerting pressure substantially axially of the fuse assembly, and means displaceable upon the blowing of said fuse to permit the ejection of the upper conductive member from the upper terminal member by the pressure exerted by said spring means.

3. In a fused circuit breaker, the combination with upper and lower terminals having seats for receiving a fuse assembly, and spring means for pressing said seats towards each other for wedging the fuse assembly between said seats, of a fuse assembly comprising an elongated insulating tube having conductive means at the opposite ends thereof for pivotally supporting the tube on the lower seat and for wedging engagement with the upper seat, whereby said fuse assembly is normally retained in operative position by pressure exerted by said spring means, and fuse means extending through said tube, said fuse means having an enlarged head for seating upon the upper conductive means and a terminal wire adapted to be clamped to the lower conductive means, one of said conductive means including a pivotally mounted member operable upon the blowing of the fuse means to permit the upper end of the fuse assembly to drop from the upper seat by the combined effects of gravity and the pressure exerted on said fuse assembly by said spring means.

4. In a circuit breaker, a replaceable fuse assembly comprising an expulsion tube, a conductive member pivotally supported at one end of said tube and having a pair of laterally extending lugs, a conductive member at the opposite end of said tube and having a pair of laterally extending lugs, and a fuse extending through said tube and serially connecting the said conductive members. the said lugs being adapted to support said fuse assembly between terminal members that are spring-pressed towards each lugs being spaced from the axis of said tube.

5. In a circuit breaker, the combination with a pair of vertically spaced terminals having seat portions for receiving a fuse assembly, insulating supporting means, and means rigidly securing each terminal to said supporting means, the upper terminal being resilient for yieldingly urging said seat portions towards each other to exert pressure substantially along a fuse assembly seated between said terminals, of a fuse assembly comprising an elongated tube of insulating material, a conductive collar on one end of said tube, a member pivoted on said collar and having means for engagement with the seat portion of one of said terminals, a conductive memher on the other end of said tube and having means for engagement with the seat portion of the other terminal, and a fuse extending through said tube and serially'connected between said pivoted member and said conductive member.

6. The invention as claimed in claim 5, wherein the seat-engaging means of the said pivoted member is spaced from the pivotal axis thereof, whereby a pivotal movement of said member alters the distance between the seat-engaging means on said pivoted member and the seatengaging means on said conductive member.

7. In a circuit breaker, the combination with a fuse assembly comprising an elongated tube of insulating material, conductive members at each end of said tube and each having seating means for engaging a terminal, a fuse, and

means for serially connecting said fuse between said conductive members, of terminal means for supporting said fuse assembly, said terminal means comprising a lower terminal having seat means for receiving the seating means of one conductive member of said fuse assembly to pivotally support the fuse assembly on the lower terminal, and an upper terminal having a pair of parallel members rigidly secured thereto, the lower faces of said parallel members having seat portions adapted to receive the seating means of the other conducting member of the fuse assembly when the latter is rotated upwardly into operative position, said parallel members being resilient and yieldingly urged towards said seat means, whereby pressure exerted approximately along said fuse assembly retains the latter in operative position between said terminals.

8. The invention as claimed in claim 7, wherein the seat portions of said parallel members are spaced forwardly of a vertical plane through said seat means of the lower terminal, whereby the fuse assembly is supported on said terminals in a forwardly inclined position.

9. The invention as claimed in claim '7, wherein said parallel members are of resilient metal and constitute the means for yieldingly urging said members towards said seat means of the lower terminals.

10. The invention as claimed in claim 7, wherein means is provided for pivotally mounting one of said conductive members upon said tube, said pivotally mounted member being operable upon the blowing of a fuse to release said fuse assembly from the upper terminal.

11. A circuit breaker comprising blade means, a pair of vertically spaced terminal members, means on the lower terminal member providing a pivotal support for one end of said blade means, and a seat on said upper terminal member for receiving the other end of said blade means and supporting the same in inclined position, said seat comprising a pair of spaced resilient members.

12. A circuit breaker as claimed in claim 11, wherein said members comprise a single rod bent back upon itself.

13. A circuit breaker as claimed in claim 11, wherein the contacting surfaces of said blade means and one of said terminal members are surfaces of different curvature, whereby the contact engagement of said surfaces is of an order substantially less than surface contact.

14. A circuit breaker as'claimed in claim 11, wherein the contacting portions of said resilient members and said blade means are surfaces of different curvature, whereby the contact engagement between the same is restricted to the order of line contacts.

15. A circuit breaker as claimed in claim 11, wherein said blade means comprises an expulsion tube of insulating material, a conductive member at each end of said tube, a fuse element within said tube and electrically connecting said conductive members, and means displaceable upon the blowing of said fuse element to permit the ejection of said blade means from the upper terminal member by the force exerted by said resilient members.

16. A circuit breaker as claimed in claim 11, wherein said resilient members are rods reversely bent to define the seat, the ends of the rods flaring from each other to form a guide for the introduction of the blade means into the seat.

17. A circuit breaker as claimed in claim 11,

iii

accents wherein said resilient members are rods each having a portion for rigid connection to an in sulator, and each bent to a complete loop between the seat and the connection portion thereof.

In 18. A circuit breaker comprising a cylindrical insulator, bracket means engaging an interme-= diate portion of said insulator for mounting the terminal members, and spring means yieldinely said seats toward each other to exert pressure approximately axially of said blade means, seat of the upperterminal member and the cooperating conductive portion oi the blade means comprising surfaces oi dihferent curvatures whereby the contact engagement oi said suriaces is restricted to less than lull surface contact. v i

so. A circuit breaker as claimed in claim it, wherein said upper terrninal member is resilient oi itself constitutes the spring" means tor said. seats toward each other.

in circuit breaker, the combination with a vert cally arranged tubular insulating" nieinber hav conductive members at the opposite ends thereoi, a closure for the upper end oi said tu= bills" insulating member, closure cent end oi the fuse engagement with an connected between said conductive and supporting on s id. con ior reception in a pair of *wrimi al a pair of vertically spaced terini portions defining seats winch to each other for receiving the re ve displace= s associated he suppo t is a;

seat to initiate removal or the in= from the upper tei nal seat,

as clamping exerted by yield 2 the ineinber nal seat. cult breaker as claimed in claim 2i, the said portion of one terminal which es a seat consists of spaced rod bers, and the said resilient rod members so the nieans yieldinsly tuning the said seats toiva ds each other.

2. in a fuse disconnect switch, palr oi spaced terminals, an insulatincnienlber having conductive members at the opposite ends thereoi, means pivotally supportins'one oi said conduc tive members on one of said terminals, latch means ovably'rnounted on the second conduc= tive member for latching the same to said second terminal, a iuse electrically connected between said conductive members, and means for directand havingnieans for pivotally supporting a re associated conductive nieinber, ex rough said insulating member and means ing upon said latch means gaseous pressure developed by the blowing of said iuse, thereby to release said insulating member from one of said terminals upon the blowing of the fuse.

24'. In a fuse disconnect switch, the combination with a pair of spaced terminals having seats for receiving the ends of a fuse assembly, at least one terminal including spring means tending to force said seats towards each other; oi

a fuse assembly comprising a tubular insulating member having conductive members at opposite ends thereof, means ior pivotally supporting one of said conductive members on the seat of one of said tenals, a fuse within said insulating member electrically co ected between said conductive members, and a latch member rnovably mounted on one conductive member and normally positioned to latch the luse assembly in operative position between the seats of said terminals, said latch member including an actuating por tion operable by the gaseous pressure developed by the blowing or the fuse to move said latch member out of latching position, thereby to per= unit the ejection of the fuse assembly from at least one terminal by the pressure exerted by said spring means.

25. In a fuse disconnect switch, the cornbina= tion or a pair of spaced terminals, on expulsion tube supported on said terminals, a fuse ex through said tube, a closure ior one end or and movably supported upon said tube, and means carried by said closure for latching engagement with one oi said terminals, said latching engagement being destroyed when said closure moved by gaseous pressure developed Within said tube by the blowing oi the ifuse.

26. A drop-out iused circuit breaker oi the type including a pair or vertically spaced ter= noinal niernbers each having contact moms, a fuse assembly comprising; an elongated expulsion tube housing a renewable iuse means and having a pair oi conductive members, said fuse means extending through said tube and lrieins' electrlcallp connected between said conductive mean here, and means for detachably said ruse assembly upon said terminal members with the conductive members thereoi engaging" the respective contact means; characterized by the that the contact means otthe ter= in rial includes a resilie member havi' a lower surface presented s the contact neans the lower terminal, d resilient member con stituti" spring means ior pressing s contact sovvards each other; the conduct their oi said ius assembly no ally so spaced that the contact means are forced apart against the iorce oi resilient member the upp r conductive inernber oi iuse assembly is forced beneath the said lower sur lace oi the upper contactnieans, and said ruse assembly includes means displaceable upon the blowing oi said iuse means to permit the elec tion oi said upper conductive rnern from the upper contact means by the iorce exerted by said spring means.

27. in a fuse disconnect switch, the combinetion or" a pair or spaced terminals, on expulsion tube supported on said terminals, a fuse extend lug" throuuh saidtube, a closure for one end of said tube, means on said closure and engaging one of said terminals to form a yielding latch for retaining said tube in operative position between said terminals, and means supporting said closure on said tube for movement from its closed latching position into an open latch-re leasing position, whereby movement of the closure in response to the pressure developed by the blowing of said fuse releases said latch.

28. In a fuse disconnect switch, a pair of spaced terminals, one terminal having a seat for receiving and pivotally supporting one end of an expulsion tube and the other having a seat for receiving a latch element, an expulsion tube having a conductive member at one end for engagement in said first terminal seat, a conductive closure member on and movably mounted across the other end of said tube, said closure member including a latch element cooperating with said second terminal seat to retain said tube in operative position between said terminals when said closure member is in closed position, an explosive charge and an ignition wire at one end of saidtube, one end of said wire being connected electrically to the adjacent conductive member, and a wire connecting said ignition wire to the other conductive member.

29. A gravity operated drop out fuse comprising a pair of spaced terminals, a seat on one terminal, a yielding contact member on the other terminal, a fuse support having at one end an element adapted to be removably engaged in said seat to provide a pivotal mounting of said tube on the seat terminal, a latch element at the other end of saidtube for latching engagement with said yielding contact member when the said other end of the tube is rotated upwardly to wedge said tube between said terminals, a fuse element within said tube, and means on said tube and movable by the pressure established within said tube when the fuse blows for moving said latch element out of engagement with said yielding contact member.

30. A fuse element comprising an expulsion tube having a conductive collar at each end, a seat within one end of said tube for receiving an explosive fuse cartridge, a latch member at the cartridge seat end of said tube, means mounting the latch member upon the adjacent collar for movement in response to the reaction caused by the explosion of a cartridge within said seat, trunnions on the collar at the opposite end of said tube, and clamping means on the collar at the opposite end of said tube for receiving the terminal of a fuse link inserted in said seat.

31. A fuse element as claimed in claim 30, wherein said mounting means comprises a piv oted closure for retaining a cartridge upon said.

seat, and said latch member is integral with said closure and less remote from the axis of said tube than is the pivotal axis of said closure.

32. A fuse disconnect switch comprising a lower terminal having journals thereiman upper terminal having a resilient contact horn projecting beyond a vertical line through said journals, an expulsion tube having a trunnion at one end for reception in said journals, a closure for the opposite end of said tube and having a portion adapted to be forced into contact with the lower face of: said contact horn to yieldingly retain said tube between said terminals and in an inclined position, and a fuse element extend-- ing through said tube, said closure being pivoted on said tube for rotation about an axis offset from a line passing through said journals and the portion of said resilient contact horn engaged by said closure.

33. The invention as set forth in claim 32, wherein said fuse element comprises an explosive cartridge seated in the upper end of said tube and retained therein by said closure, an ignition wire in said cartridge, and a flexible wire connected to said ignition wire and extending outside of the lower end of said tube for electrical connection to said lower terminal.

34. Apparatus of the class described comprising an expulsion tube of insulating material, conducting members carried by and at each end of the tube, an explosive cartridge removably seated in one end of the tube, an end closure for retaining the cartridge in the tube, said cartridge including an ignition wire contacting an explosive charge within a. shell and a conductor connected to said ignition wire and extended through said tube, and clamp means on the member remote from said cartridge for clamping the conductor thereto.

35. The invention as set forth in claim 34, wherein said closure is pivotally mounted on the collar adjacent thereto and includes a terminal contact portion less remote from the axis of the tube than the pivotal axis of said closure.

36. In a fuse disconnect switch, a pair of spaced terminals, an expulsion tube, a conductive member on one end of said tube and carrying trunnions for pivotally mounting said tube on one of said terminals, a pivoted closure for the other end of said tube, a fuse element extending through said tube and having one end contacted by the closure when the latter is in closed position, means for securing the opposite end of said fuse element to said conductive member, and a contact horn for yieldingly receiving the said closure to support said tube between said terminals, said horn and closure having cooperating portions which are moved relatively to each other to release said closure from said horn when the closure is rotated by the gas pressure resulting from a blowing of the fuse element.

37. In a circuit breaker, an expulsion tube, a conductive closure for one end of said tube, a conductive member mounted on the opposite end of said tube, an explosive cartridge retained in said tube by said closure, an ignition wire in said cartridge, and a conductor electrically connected to said ignition wire and extending through said tube for connection with said conductive member.

38. In a fuse assembly of the character described, an elongated insulator, a hinge member on one end of the insulator, a fuse unit pivotally mounted on said hinge member, a terminal means secured to the opposite end of said insulator, said terminal means including a terminal seat for the fuse unit and a spring arm rigidly secured at one end to the insulator, and a terminal on the fuse unit for engagement with said seat.

39. A. fuse assembly as claimed in claim 38, wherein the cooperating surfaces oi the fuse unit terminal and of the terminal seat are both curved surfaces.

40. In a fused circuit breaker, the combination with a support of insulating material, a pair of connector elements secured in vertically spaced relation on said support and having means for making connection to line Wires, and means as sociated with each of said elements for establishing an electrical connection to a fuse assembly, at least one of said means including a pair of herb zontally spaced resilient members having their inner ends rigidly clamped to the associated connector element, the resilient members having lower surf-aces for engaging lugs on a fuse assembly, of a fuse assembly including an expulsion tube and a pair of contact members longttudinally spaced with respect to said expulsion tube, a fuse element extending through said tube and normally electrically connected between said contact members, and means pivot-ally supporting said fuse assembly for angular movement into approximately vertical position to establish electrical connections between the contact members and said means associated with the respective connector elements.

41. A fused circuit breaker of the type including apair of. vertically spaced terminals, a fuse assembly pivotally supported for movement into approximately vertical position 'to close a circuit between said terminals, and means for latching said fuse assembly in said approximately vertical position, characterized by the fact that the upper terminal includes a member having means for establishing connection to a line wire, and a pair of horizontally spaced resilient members having their inner ends rigidly secured to said member, said resilient members being reversely bent to form seats'for receiving lugs on the fuse assembly, whereby said resilient members comprise the latch means for latching the fuse assembly in approximately vertical position.

42. In a fused circuit breaker, the combination with an insulating support and a pair of terminal means secured in vertically spaced relation on said support, and means for establishing line wire connections to said terminal means, the upper terminal means including a resilient member having a rigidly clamped inner end and a reversely bent resilient outer end, of a fuse assembly including an expulsion tube, a fuse element extending through said tube, a closure for normally retaining the upper end of the fuse element within said expulsion tube, and means pivotally supporting said fuse assembly for angular movement to carry said closure into engagement with the lower face of said resilient member.

43. A fuse assembly as claimed in claim 42, wherein the contacting surfaces of said resilient member and said expulsion tube closure have different radii, whereby the contact engagement of said surfaces is less than surface contact.

GEORGE L. CARLISLE.

Images