US2654814A

US2654814A - Electrical switch

Info

Publication number: US2654814A
Application number: US32465A
Authority: US
Inventors: Robert A Gesellschap
Original assignee: James R Kearney Corp
Current assignee: James R Kearney Corp
Priority date: 1948-06-11
Filing date: 1948-06-11
Publication date: 1953-10-06
Anticipated expiration: 1970-10-06

Description

Oct. 6, 1953 Filed June ll, 1948 R. A. GESELLSCHAP ELECTRICAL SWITCH 3 Sheets-Sheet 1 ROBERT A. GlisELLsczd/u4 ATTORNEY Oct. 6, 1953 R. A. GESELLSCHAP 2,654,814

ELECTRICAL SWITCH Filed June'll, 1948 3 Sheets-Sheet 2 /f /09 l I,

y INVENTOR ROBERT A. GEsELLscHAP ATTORNEY Oct. 6, 1953 Filed June ll, 1948 FIG. 4

FIG. 3

R. A. GESELLSCHAP ELECTRICAL SWITCH 5 Sheets-Sheet 3 INVENTOR ROBERT A. GESELLSCHAP BY M ATTORNEY Patented Oct. 6, 1953 ELECTRICAL SWITCH Robert A. Gesellschap, Kirkwood, Mo., assignor to James R. Kearney Corporation, St. Louis, Mo., a corporation of Missouri Application J une 11, 1948, Serial No. 32,465

Claims.

This invention relates generally to electrical switches and more specically to a reclosing switch structure which is adapted for use in maintaining service of electrical energy from feeder circuits to an important user of electrical energy, a hospital, for instance, the predominant object of the invention being to provide a reclosing switch structure, adapted for the use referred to above, which is of such improved construction and arrangement that it is capable of performing its intended function in an improved and highly efficient manner.

In the case of an important user of electrical energy where failure of electrical service would create a serious emergency, such, for instance, as a hospital, it has been the practice heretofore to provide such a user with two feeder circuits, one of said circuits being the preferred circuit which normally feeds electrical energy to the user, and the other circuit being an emergency circuit which is placed in service only in the event a failure occurs with respect to the preferred circuit. It is highly essential, in the event of a failure on the preferred feeder circuit of such an important user, that the switch-over to the emergency circuit be made instantaneously so as to avoid even slight interruption of service of electrical energy to the user.

The reclosing switch structure of the present invention is so constructed and arranged, and is capable of such use, that immediately on failure of service to the user over the preferred circuit a switch-over to the emergency circuit is automatically made in a fraction of a second so that there is practically no interruption of service of electrical energy to the user. In addition to the foregoing, the improved switch structure of the present invention includes fusible means which affords protection against cla-mage resulting from overioads and short-circuits occurring on either the preferred circuit or the emergency circuit, depending on which of said circuits is in service at the time the fault occurs.

Fig. l is a front elevation of the improved switch structure of the present invention.

Fig. 2 is a fragmentary, side elevation of the improved switch structure of this invention with parts broken away to permit of the structure being drawn to a larger scale than would otherwise be possible.

Fig. 3 is an enlarged, fragmentary, vertical section of an upper portion of the improved switch structure taken on line 3 3 of Fig. l.

Fig. 4 is a section taken on line 4-4 of Fig. 3.

Fig. 5 is a vertical section taken on line 5-5 of Fig. 3.

(Cl. 20G-126) Fig. 6 is an enlarged vertical section taken on line 6 6 of Fig. 1.

In the drawings, wherein is shown for purposes of illustration, merely, one embodiment of the invention, A designates the improved switch structure generally. The switch structure A includes a pair of insulators I and 2 which preferably though not necessarily, are disposed vertically, said insulators being spaced apart in a horizontal direction as is shown to good advantage in Fig. l. The insulators I and 2 are embraced respectively by

suitable brackets

3 and 4, and these brackets are secured to an elongated, horizontally disposed channel member 5 adjacent to the opposite ends of said channel member, said channel member being secured at its approximate longitudinal center to a clamping structure 6 which clampingly engages a cross arm, or other support S, for supporting the switch structure in position for use. The lower portions of the insulators I and 2 have secured thereto saddle members 'I and 8 and fixed to these saddle members is an elongated, horizontally disposed bar 9 which serves as a bus terminal and extends from one to the other of said insulators I and 2.

The bar 9 is secured adjacent to its opposite ends to the saddle members 'I and 8 by bolts I0 and II, the bolt I0 serving also to secure to the bar 9 and the saddle member l of the insulator I, a supporting member I2 which provides support for a fuse cartridge Ca. The cartridge supporting member I2 includes an upstanding ilange I2a through which the shank portion of the bolt IG ext-ends, and said cartridge supporting member is provided with a head portion I 2b which is shaped as is shown to good advantage in Fig. 6 and is provided with trunnions I3 which extend outwardly in opposite directions from the opposite side faces of said head portion. Preferably the head portion of the cartridge supporting member I2 is provided with arcuate centering flanges I 2c which extend outwardly from the opposite side faces thereof.

The fuse cartridge Ca is of the expulsion type and comprises an open ended tube I4 formed of electrical insulating material. The tube I4 is preferably of composite construction, embodying an inner tubular portion I4a of horn fiber, and outer tubular jacketing portion I 4b of Bakelite, or other insulating material having equivalent weather-resisting properties. It'has been found advantageous to employ horn ber in the construction of the tube I4 of the cartridge Ca because of the fact that such material is characterized by the ability to give off gas in the presence of the heat of an electric arc which tends d to extinguish the arc. The tube I4 of the fuse cartridge has iixed thereto at its upper end a head l5 which is provided with opposed, downwardly and outwardly inclined shoulders I5, said head being provided, also, with an upstanding tubular neck portion Il which is externally screwthreaded and screwthreadedly receives a cap I8. The head I5 of the tube I4 of the fuse cartridge Cia is provided with a rearwardly extended lug I9 (Fig. 3) to which is secured a vertically disposed latching member 20, said latching member being secured tov said lug I3 by a screw 2l and a second screw 22 being provided for securing the lower portion of said latching member to the lower portion of the head I5. The head i5 has extended forwardly therefrom a lug 23 which supports a horizontally disposed rod 24, portions of said rod 24 extending outwardly in opposite directions from said lug. Also,

a rod 25 is extended downwardly and forwardly from said head I 5..

At its lower end the tube I4 of the cartridge Ca is provided with means for efecting its pivotal and detachable connection with the cartridge supporting kmember l2. This means comprises a hinge member 26 which is pivotally connected to the Iouter end of a bracket 21,A said bracket. being rigidly secured to and projects at a right angle relativev to the cartridge tube I4. The bracket 21, which is spaced upwardly from the lower end or the cartridge tube I4, is provided with a downwardly opening recess 28 (Fig. 2) which forms a housing for a pivot pin 29, the hinge member 26 being provided with an arm 30 which extends into the recess 28 of the bracket 21 and is pivotally engaged by the pivot pin 29. The hinge member 23 is provided with a forwardly extending portion 23a which underlies. the lower end of the cartridge tube I4, and the opposite end of said hinge member is bifurcated and terminates in opposed, forwardly opening, hook-like portions 2321 which engage the trunnions I3 projected from opposite side 'f aces of the head portion .I 2b .of the cartridge supporting member I2.

The cartridge Ca. is provided with a fuse link 3i having a head 3.2. which is suitably seated within the upper portion of the fuse cartridge Ca and extends downwardly through the tube I4 of said cartridge, the lower portion of said fuse link extending from the open lower end of the cartridge tube and partially `embraces the forward portion 25a off the hinge member 23 and is engaged by a binding post 3.3 which is mounted on the hinge member 26 at a side thereof (Fig. 2). Thus, un-

der normal operating conditions, the cartridge swings about the axes of the trunnions I3, there being no movement of the hinge member 26 relative to the cartridge tube I4 because such relative movement of the hinge member is prevented by the fuse link 3 I.

Disposed at the upper end .of the fuse cartridge Ca is a housing 34 which is shaped as is shown to good advantage in Figs. l, 2 and .3, said housing being closed by wall portions at its top, sides. and rear end, and being open at its front and bottom. rIhe housing 34 is secured to a saddle member 35 which is fixed to the upper portion of the insulator I. It will be noted by referring to Fig. 3 that a screw 33 serves as the means for securing the housing v34 to the saddle member 35, said screw 33 serving also to secure in place relative to the housing 34 a terminal 31 for incoming current, and an upper contact element 38, an .upwardly extended loop portion 39 of the upper contact element 38 and a lower portion of said terminal 31 being interposed between the rear wall of the housing 34 and the saddle member 35. The shank of the screw 35 passes through an opening formed through the rear wall of the housing 34, through the looped portion of the contact element 38, through an opening formed through the lower portion of the terminal 31 and is screwed into a screwthreaded opening formed in said -saddle member 35 for mounting the housing 34, the upper contact element 38 and the terminal A3'! in place relative to the insulator I. Also, .a conductor 33 for incoming current is mechanically and electrically connected to the terminal 31 by .means of a suitable connector 40.

The upper contact element 38 is formed of heavy wire, or rod-like material, which is inherently .resilient and said contact element includes horizontally spaced portions which extend forwardly from the lower portion orf the loop portion 39. These horizontally spaced portions of the contact element 38 are provided with coiled portions 4I which Aprovide said contact portions with additional resiliency. Also, the forward portions of said spaced contact portions are flared at their forward portions, as is shown at 38 in Fig. l. It is to be noted that portions of the horizontally spaced portions of the contact element 38, which are located just rearwardly of the forward, flared portions of said contact element, contact with the rod 24 of the fuse cartridge Ca. Because of this arrangement an electrical path is provided which includes the conductor 39, the terminal 31, the contact element 38, the head I5 of the fuse cartridge Ca, the fuse link whose head 32 contacts internally with said cartridge head, the hinge member 26, the cartridge supporting member I2, the bar 9, and an outgoing conductor 42 which is mechanically .and electrically connected to the bar by Asuitable securing means 43.

.Mounted in openings formed in the opposed side walls of the housing 34 and extended transversely of said 'housing is a rod 44 (Fig. 3) on which a. latch 45 is supported 1for rocking movement.. The latch 45 comprises a main body portion which is provided with an opening through which the rod 44 extends, and extended forwardly from said main body portion is an extension which is. provided with an inclined forward face 45a .and a latching abutment 45h which is adapted to engage the upper end portion of the 'latching member 20 that is secured to the head I5 of the fuse cartridge Ca. The latch 45 has secured thereto an arm 46 which is in the vform of a flat strip of material, and said arm extends rearwardly of the housing 34, the weight of the combined latch and arm being so distributed relative to the rod 44 as to Vcause -said combined structure to .normally occupy the position in which it appears m full lines in Fig. 3 where the fuse cartridge Ca is locked in its effective operative position. By referring to Fig. 5 it will be noted that tubular spacers 41 embrace the rod 44 in interposed relation with respect to the side walls of the housing 34 and opposite side faces of the latch 45, whereby the latch is centered relative to the housing in a transverse direction.

The top wall of the housing 34 is provided with a short, upwardly extended, tubular extension 4B which is received in the lower portion of the bore of an insulator 4.9. The insulator 49 is secured in position by a clamp 53 which embraces the lower portion of said insulator and is secured to an opstanding flange structure 5I formed on the top wall of the housing 34, said clamp being of conventional design and being secured in embracing relation with respect to the lower portion of the insulator by a bolt and nut assembly 52 and being secured to the flange structure 5| by a bolt and nut assembly 53. Supported by the upper portion of the insulator` 49 is a relay 54 of the no voltage type, said relay comprising a coil structure 55 with which is operatively associated an armature 56, and said coil structure being provided with a suitable frame 51.

The relay 54 includes a cylindrical housing 5B which is formed of electrical insulating material, said housing being provided with a top wall 59 which likewise is formed of electrical insulating material to which the coil frame of the relay is attached by means of a suitable bracket 68. rlhe cylindrical housing 58 of the relay 54 is supported by the upper portion of the insulator 49, the means for attaching said cylindrical housingr to said insulator comprising a pluralityT of shoes 6| which engage the circumferential face of the upper portion of the insulator 49, said shoes being resiliently supported by spring portions 62 which are substantially U-shaped, as is shown in Fig. 3. The outer portions of the U-shaped spring portions 62 are secured to the wall of the cylindrical housing 58 at the outer face thereof by bolt and nut assemblies 63, the lower bowed portions of said U-shaped spring portions resting on a rib 49' of the petticoat type insulator 48.

Pivoted to the armature 56 of the relay 64 is a ceramic rod 64 which extends downwardly through the bore of the insulator 49, the pivotal attachment of the ceramic rod 64 to the armature 56 being effected by an element 65 which is set into a notch formed in the upper portion of the rod 64 and is apertured to receive a pivot pin 66 which passes through apertures formed through spaced portions of the armature 56 (Fig. 4). The relay structure includes a stop member 61 which preferably is formed of heavy wire, said stop member including spaced vertical portions 61a, spaced horizontal portions 61h which extend forwardly from the lower ends of said spaced vertical portions, and a bridge portion 61e which joins the forward ends of said spaced horizontal portions. The upper end portions of the spaced vertical portions of the stop member 61 are secured by fastening devices 68 to a part of the frame of the coil structure of the relay. The pivot pin 66 extends outwardly suflicient distances beyond the spaced portions of the armature 56 so that when the armature moves downwardly relative to the coil structure of the relay, as will presently appear herein, the opposed extended end portions of said pivot pin 66 will strike the spaced horizontal portions of stop member 61 and thereby arrest such downward movement of said armature and of the rod 64 attached thereto. The rod 64 has attached to its lower end, by means of a screw 68', a head 68 which may be formed of metal so as to give additional weight to said rod.

By referring to Figs. 1 and 2 it will be noted that the hinge member 26 has extended from its opposite sides a pair of horizontally alined pins 89 which are engaged by portions of a resilient member 10. This resilient member is formed of heavy resilient wire, or rod material, and its lower, rear portion is in the form of a loop with spaced vertical portions 18a extended upwardly from said loop. These spaced vertical portions merge into spaced upwardly and forwardly curved portions b which in turn merge into downwardly and rearwardly extended portions 6 10c that contact with the pins 69 which are ex' tended outwardly in opposite directions from the hinge member 26.

When the fuse cartridge Ca is in the closed switch position, as is shown in Fig. 2, the pins 69 force the spaced portions 19o of the resilient member 18 rearwardly whereby said resilient member 10 is subjected to stress that tends to rotate the hinge member 26 about the trunnions I3. However, at this time the upper portion of the fuse cartridge is latched in the closed switch position by the latch 45 and rotation of the hinge member 26 about the trunnions I3 by the resilient member 10 is prevented.

Supported by the lower portion of the insulator 2 is a housing 1|, a bracket 12 being secured to the saddle member 8 and to said housing for effecting support of said housing 1|. The housing 1| is closed at its top and opposite sides, and in part at its ends, said housing being open at its bottom. Pivotally attached to the forward portion of the housing by a pivot element 13 is a carriage 14, said carriage comprising opposed side walls which are joined at their upper rear ends by a rear wall 15. The carriage i4 is pron vided, also, with a Wall 16 which joins the lower portion of said opposed side walls, said wall 16 being of angular shape and being provided at its lower end with a notch 11.

At its upper rear portion the carriage 14 is provided with spaced ears 18 which pivotally receive therebetween an end portion or a toggle link 19, the opposite end portion of said toggle link being pivotally attached to an end portion of a toggle arm 80. The toggle arm 88 is pivoted within the housing 1| by a pivot element 8| which is supported at its opposite ends in openings formed in the opposed side walls of said housing 1i, and said toggle arm is provided Iwith a hook-like rear end portion 82. Also, a coil spring 83 is arranged within the housing 1|, the forward end of said coil spring being attached to the upper rear portion of the carriage 'Hi and the rear end of said coil spring being attached to a spring anchoring pin 84 located within the rear portion of the housing 1|. It is to be noted that when the toggle arm 86 is in the position in which it is shown by full lines in Fig. 2 the portion of said arm which extends forwardly of the pivot element 8| contacts with the lower face of the top wall of the housing 1| Also, at this time, the pivotal point of attachment of the rear portion of the toggle link 19 to the forward end portion of the toggle arm 80 is located above a line ex tended between the centers of the pivotal point of attachment of the forward end portion of the toggle link 19 to the carriage 14 and the pivot element 8| of the toggle arm 86. Because oi this arrangement a set toggle is provided which prevents the coil spring 83 from drawing the upper rear portion of the carriage in a rearward direction.

The opposed side walls of the carriage are provided with alined slots 85 and these slots receive opposed trunnions 86 which extend outwardly in opposite directions from the upper rear end of opposed portions 81 of a cartridge-supporting member 88. These opposed portions 81 of the member 88 are both shaped as is shown in Fig. 2 being spaced apart and rigidly secured together. In other words; the opposed portions 81 of the cartridge-supporting member 68 include alined top elements 88a, and alined forward elements 88h which join said top elements, the trunnions 86, previously referred to, being mounted at the rear .ends .of the top velements '38a .and being projecting into the. slots 8.5 of the `carriage 'l-Ll..

The cartridge-supporting member 8e supports a :fuse cartridge Cb which includes a tube structure SQ constructed in accordancev with the tube structure I of the cartridge Cc, as heretoforey described herein. The tube structure 9S of the fuse cartridge Cb has xed thereto at. its lower end a bracket .S I said bracket having a tubular portion which embraces the lower portion of the tube structure Sii. Extended from the upper portion of the tubular portion of the bracket SEI is an arm S2 that is provided with an enlarged end portion through which an opening is formed, said being disposed between the opposed members oi the .cartridge-supporting member .3S and being pivoted thereto by a pivot pin @3 that passes through the opening .formed through the end portion of .the arm 9.2 and is seated openings formed through said opposed portions of said cartridge-supporting member 3%. The bracket 9! is provided, also, with a lower arm which extends from the lower Iend portion of the tubular portion thereof, said arm mi having laterally extended extensions e which normally are seated in the notch 'il' formed at the lower portion of the angular wall 'l5 of the carriage '.Hi. The tube `structure of the fuse cartridge Cb has xedly mounted thereon at the upper vend thereof a head S5 having a reduced, externally screwthreaded neck portion Si on which a cap SS is screwthreadedly seated, .an upper cartridge contact 99 formed of heavy wire being supported by lugs 99' formed on said head Sib.

The fuse cartridge 4Cb is provided with a fuse link AI @Il having a head IBI which is seated in contact with inner portions of the head S5 of the fuse cartridge Cb, said fuse link extending through the tube structure of said fuse .cartridge and bei-ng projected beyond the open lower end of said tube structure where the outer portion of said extended part of the fuse link is secured to a .lower portion of cartridge-supporting .member 88 by a binding post HB2. It will be noted that the cartridge-supporting member 88 includes a shoe H33 which underlies the lower end portion of the fuse cartridge for aiding in the support of said fuse cartridge.

At its upper end the insulator E has fixed thereto a saddle member lill; to which a terminal E95 is. secured, said terminal having connected thereto by a suitable connector Iiian incoming electrical conductor Ill?. Also secured to the saddle member H34 and in electrical and mechanical contact with the terminal l is an upper contact H38, said upper Contact being formed of .heavy resilient wire and being provided with spaced portions between and in contact with which the portion. 95a of the upper cartridge contact moves when the fuse cartridge Cb is operated to the closed switch position, as will be herein-after explained. The upper contact is provided with coiled portions les which impart resiliency to said upper contact.

The switch structure of the present invention includes a transfer rod II'i) which is supported for rotation by a lug II I formed on the top wall of the housing 'II and by a bearing element H2 secured to the bar 9. At one of its ends the rod III'I is provided with a crank I I3. At its opposite end said transfer rod .I Ill is shaped so as to be provided with an offset portion IIA whose end portion is extended inwardly, as indicated at H5, so as to contact with the toggle arm Si! when .said toggle .arm is. .in the position .in which it is shown by .fulllines in Fig. 2.V

The switch P which is associated with the insulator I is connected into the preferred feeder circuit of an important user of electrical energy, while the switch E which is associated with the insulator 2 is connected into the emergency feeder circuit of such important electrical .energy user, the preferred feeder .circuit .normally being in service with the switch `P in the closed switch position, and the switch. E normally being in the open switch position. When the preferred feeder circutv is in service .current from said preferred `circuit energizes the coil structure 55 ofthe relay 5e whereby the rod .5d will be held in an -elevated position. In the event, however, electrical energy ceases to flow through .the preferred feeder circuit the coil structure of the relay .56 will be deenergized thereby permitting the rod .64 to drop downwardly and strike the arm 65 of the latch zie and move said latch to the position vin which it is shown by dotted lines in Fig. 3 where the latch abutment 5b will be .raised out of contact with respect to the upper portion of the latching member 2G.. The resilient .member 'l will then rotate the hinge member 2B about the trunnions I3 so as to cause the fuse 'cartridge Ca to swing outwardly and downwardly .about said trunnions I3. As the fuse cartridge swings` downwardly it strikes the crank IIS of the transfer rod l i@ so as to rotate said rod and cause the inturned portion I I5 thereof to move the toggle arm 80 upwardly. This will break the toggle provided by said toggle arm B and the toggle link 'i9 and permit the coil spring 83 to rotate the carriage 1d rapidly .about the pivot element '13 and move the fuse cartridge Cb quickly to its closed switch position where the cartridge Contact 99 contacts with the upper contact ISS to place the emergency feeder circuit in service.

In addition to the operation described above the improved switch structure of the present invention affords protection in the event an overload or short circuit occurs on the primary circuit. As a result of such an overload or short circuit the fuse link of the fuse cartridge Ca will be ruptured and the hinge member 26 of fuse cartridge Ca freed, at its outer or link-engaging end and acting under the forces imparted thereto, turns rapidly about the two axes defined by the trunnions i3 and the pivot element 29. Movement of the hinge members about the trunnions I3 is accompanied by an endwise lowering of the cartridge tube structure, which when clear of the contact element 38, swings outwardly and downwardly to the open-switch position. Here, also, the downward swinging fuse cartridge strikes the crank I I3 of the transfer rod and rotates same so as to cause the fuse cartridge Cb to be rapidly moved to its closed-switch position as has been previously explained herein.

Also, in the event an overload or short circuit occurs on the emergency circuit while the fuse cartridge Cb is in the closed-switch position, the cartridge-supporting. member will be freed at its lower end, because of the ruptured fuse link. This will result in said cartridge-supporting member swinging downwardly about the axes of the trunnions 85 with a consequent endwise lowering of fuse cartridge so that the end portion of the lower arm 94 of the bracket 9! is disengaged from the notch 'Il of the carriage 'Ill yand the cartridge Contact 98 is freed from the upper contact 108. The fuse cartridge then falls outwardly and downwardly to its open lswitch posi- 9 tion whereby the emergency feeder circuit is completely interrupted. When either the fuse cartridge Ca or the fuse cartridge Cb drops out of the closed switch position as a result of rupture of its fuse link, as described above, any arc created because of the rupture of the fuse link is eX- tinguished within the tube structure of the fuse cartridge by gas given off by the horn fiber within the tube structure because of the effect of the heat of the arc on said horn ber.

The latch 45 has associated therewith means for manually actuating said latch when it is desired to manually cause the fuse cartridge Cc, to move to the open-switch position. This means comprises a length of heavy wire HS which is coiled about one of the spacers il that embrace the rod 44 on which the latch 45 is supported (Figs. 3 and 5). A portion Ill of said length of wire extends forwardly from the coiled portion H8 thereof and extends beyond the forward end of the housing 34, while another portion H9 of said length of wire extends rearwardly from said coiled portion I I8 and is provided with a laterally extended portion |20 which overlies the member 45 of the latch 45. When it is desired to manually unlatch the upper end of the fuse cartridge Ca the forward end portion of the length of wire IIB is elevated, as indicated by dotted lines in Fig. 3, thereby causing the lateral portion i2@ of said length of wire to depress the member d of the latch and free the latch member 2U therefrom.

I claim:

1. A switch structure comprising a switch having a fuse cartridge supported for pivotal movement into and out of the closed-switch position, spring means for urging said fuse cartridge toward the open-switch position, a latch engaging and latching said fuse cartridge in the closedswitch position and means comprising a relay for actuating said latch for releasing the fuse cartridge of the first-mentioned switch for movement out of the closed-switch position on interruption of the flow of current through said fuse cartridge of said rst-mentioned switch, a second switch having a fuse cartridge supported for pivotal movement into and out of the closed-switch position and normally supported in an openswitch position when said first fuse cartridge is in the closed-switch position, normally inactive actuating means connected with said second switch, transfer means actuated by movement of the fuse cartridge of the rst-mentioned switch out of the closed-switch position to actuate said actuating means to cause the fuse cartridge of the second-mentioned switch to be moved into the closed-switch position, said relay including coil means which is energized by flow of current through the first-mentioned fuse cartridge, and a member which is held in an elevated position by the energized coil means of the relay and which is released by de-energization of said coil for latch actuating movement.

2. A switch structure comprising a switch having a pair of spaced terminals and having a fuse cartridge biased toward open-switch position and supported for pivotal movement into and out of closed-switch position relative to said spaced terminals, a fusible element associated with said fuse cartridge and completing a circuit through said spaced terminals in the closed-switch position of said fuse cartridge, a mechanically actuated latch engaging and latching said fuse cartridge in the closed-switch position and means for actuating said latch for releasing the fuse cartridge of the first-mentioned switch for movement out of the closed-switch position on interruption of the flow of current through said fuse cartridge of said first-mentioned switch, a second switch having a fuse cartridge supported for pivotal movement into and out of closedswitch position and normally supported in an open-switch position when said first fuse cartridge is in the closed-switch position, normally inactive actuating means connected with said second switch, transfer means actuated by movement of the fuse cartridge of the first-mentioned switch out of the closed-switch position to activate said actuating means to cause the fuse cartridge of the second-mentioned switch to be moved into the closed-switch position.

3. A switch structure comprising a switch having a pair of spaced terminals and having a fuse cartridge biased toward open-switch position and supported for pivotal movement into and out of closed-switch position relative to said spaced terminals, a fusible element associated with said fuse cartridge and completing a circuit through said spaced terminals in the closed-switch position of said fuse cartridge, a mechanically actuated movably supported latch engaging and latching said fuse cartridge in the closed-switch position, and means for actuating said latch for releasing the fuse cartridge of the Erst-mentioned switch for movement out of the closed-switch position on interruption of the iiow of current through said fuse cartridge of said rst-mentioned switch, a second switch having a fuse cartridge supported for pivotal movement into and out of closed-switch position and normally supported in an open-switch position when said rst fuse cartridge is in the closed-switch position, normally inactive actuating means connected with said second switch, transfer means actuated by movement of the fuse cartridge of the firstmentioned switch out of the closed-switch position to actuate said actuating means to cause the fuse cartridge of the second-mentioned switch to be moved into the closed-switch position.

4. A switch structure comprising a switch having a pair of spaced terminals and having a fuse cartridge biased toward open switch position and supported for pivotal movement into and out of closed-switch position relative to said spaced terminals, a fusible element associated with said fuse cartridge and completing a circuit through said spaced terminals in the closed-switch positlon of the fuse cartridge, a mechanically actuated pivotally supported latch engaging and latching said fuse cartridge in the closed-switch position, and means for causing the fuse cartridge of the first-mentioned switch to move out of the closed-switch position on interruption of the ow of current through said fuse cartridge of said first-mentioned switch, a second switch having a fuse cartridge supported for pivotal movement into and out of closed-switch position and normally supported in an open-switch position when said first fuse cartridge is in the closed-switch position, normally inactive actuating means connected with said second switch, a fusible element associated with said fuse cartridge of said second switch, transfer means actuated by movement of the fuse cartridge of the rstmentioned switch out of the closed-switch position to actuate said actuating means to cause the fuse cartridge of second-mentioned switch to be moved into the closed-switch position, said fusible element of the fuse cartridge of the first-mentioned switch serving to release said fuse cartridge Vfor movement out of the closed switch position on rupture `of said fusible element.

5. A switch structure comprising a switch having a pair of spaced-terminals vand having a-fuse cartridge 'biased toward open switch posi-'tion and supported for pivotal -movement into and out of closed-switch `position relative to said spaced terminals, a fusible element yassociated. with Asaid fuse cartridge and completing -a circuit through said spaced Vterminals in the closed-,switch 'position of the fuse cartridge, a mechanically actuated pivotally supported latch engaging and latching said fuse cartridge in the closed-switch position, and means for causing the fuse cartridge ofthe mst-mentioned switch Yto move vout of the closed-switch position on interruption of the flow current through said -fuse cartridge of said first-mentioned switch, a second switchhaving a fuse cartridge supported for `pivotal movement into 'and cut of closed-,switch vposition and normally supported in an open-switch position when said first fuse cartridge Vis in 'the closedswitch position, normally inactive actuating means connected with said second switch, La fusible element associated 'with said Vfuse cartridge of said second switch, transfer means actuated by movement ofthe Afuse cartridge o f the iirst-mentioned switch out of the closed-switch Cil 12 position to actuate said actuating means sto -eause the fuse cartridge of second-mentioned switch to be moved into --the closed-switch position, said fusible element of the `ii-rstmentionedstili-tch and said 'fusible element /of the lsecond-mentioned switch serving lto release `the fuse v'cartridges rot the respective switches :for `movement out of Vthe closed-switch positions on rupture of said us'ib'le elements.

ROBERT A. GESEILSCHAR References Cited in :the file :of 'this Apatent'.

UNITED STATES PATENTS Number Name Date Re. 16,917 Williams ,Mar1 v27,1928 .527,501 McLaughlin Det. 16 189.4 894,333 Ledwinka ,...V ,July 28, 19,08 963,728 Ayer ,July 5J 1910 A1,894,056 Pittman et al. Jan. ,10, l1933 2,059,796 Johnson Nov. .3, 1936 2,140,906 Froland .,Dec. 20 1.938 2,213,164 Herault Aug. 27, 1940 2,229,531 Tornquist Jan. Y21, v1941 FOREIGN PATENTS Number Country Date 360,057 Great Britain Nov. 5, 1931 543,027 France r May .26, 1922