US2421982A - Electric circuit interrupter - Google Patents

Description

`une 10, 1947. R, s, BENNETT 2,421,982

ELECTRIC CIRCUIT INTERRUPTER Filed March 9,1945

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Patented June 10, 1947 ELECTRIC CIRCUIT INTERRUPTER Ralph S. Bennett, Pittseld, Mass., assignor to General Electric Company, a corporation o New York Application March 9, 1945, Serial No.` 581,741

8 Claims. (Cl. 200-114) My invention relates to electric circuit interrupters, and more particularly to a fuser cutout type of circuit interrupter. o

It is an object of my invention to provide a new and improved fuse cutouttype of circuit interrupter. s j

It is another object of my invention to provide a new and improved indicator means for a fuse cutouttype. of circuit interrupter.

,Further objects and advantages of my invention` will become. apparent as the following description proceeds and the features. of novelty which characterize `my invention will be pointed out Withparticularity in the claims annexed to and forming a part of this specication.

Fora better understanding of my invention reference maybe had to the accompanyingdrawing in which Fig. 1 isa side elevation, partly in sectiony of an electric circuit interrupter of the fuse cutout type embodying my invention; Fig. 2 is an enlarged view. partly in section, of the fuse holder employed in Fig. 1; Fig. 3 isa sectional view taken on line k3-3 of Fig. 1, assuming Fig. 1 shows the complete structure; Fig.,4 is an enlargedview of one of the contacts `on the fuse holder of Fig. 2, and Fig. 5 is a side view of the portion of the fuse holder shownin Fig. 4 illustrating` a ymodification of the cable attaching meansffor they fuse link.v

Referring now to the drawing, I have illustrated a housing or casing'I formed of porcelain or similar.. insulating material having an integrally formed creepage` barrier 2 which separates two stationary terminal or contact assemblies generally indicated at 3 and 4, respectively mounted the contact assembly 4 from being displaced from its latched position with the projections 9 of the support 5 being engaged in the recesses IIJ in housing I. kIhe member 6 of contact assembly 4 isa spring contact or terminal clip for engaging with a corresponding contact of a fuse device,

such as will be'rdescribed hereinafter.

The support 5 'is provided with lanced-out portions I2 which act as backing members for limiting the movement of spring clip lIi. yThe memf ber 'I'includes ar loopedor cylindrical lead-re- 2 ceiving portion or passageway I3.l A plurality of screws I4 are provided in the cylindrical leadreceiving portion or terminal I3 for clamping a conductor or lead inserted in the lead-receiving portion or passageway I3. The lead-receiving portion I3 of Contact assembly 4 is mounted adjacent a leadentrance opening I5 in the lower part of housing I throughwhich external connections with contact assembly 4 may be made.

The contact assembly 3 is substantially identical with the ycontact assembly 4 described above and is mounted adjacent lead entrance opening I6 above projection Il formed integrally with the upper part of housing I. Contact assembly 3 includes members 5, 6 and I identical with the corresponding Vmembersr ofk contact assembly 4. The corresponding parts of contact assembly 3 are designated by the same reference numerals as these portions of contact assembly 4.

The contact or terminal assemblies 3 and 4 described thus far and the method of assembling them in housing I are disclosed and claimed in my prior Patent 2,011,391granted August 13, 1935, and assigned to the same assignee as the present application.

To the back of housing Ir there is secured a mounting bar I8 for attachment of the cutout to a suitable supporting structure (not shown).

This mounting bar I8 is preferably cemented as indicated at I9 into an external recess 2l) in housing I.

In order to provide a closure for housing I, I provide a cover or door 2l preferably made from a molded insulating compound or the like, which door or cover includes an integral handle or eye 22 which may be either grasped manually or engaged by a suitable form of switchstick to open and close the cover 2I with respect to housing I.

Door 2i is pivotally mounted to the lower front portion of housing I b-y means of insulating hinge pins 23 which pass through openings in housing I and threadedly engage door or cover 2I. The cover 2! is also provided with a barrier 24 integrally formed'witli the inner surface of the door which cooperates with creepage barrier 2 of housing I to lessen the possibility of flash-over between the contact assemblies 3 and 4 by virtue of conducting gases passing therebetween.

The cover or door 2| is adapted to support a fuse holder generally indicated at 25 in Figs. l and 2. Fuse holder 25 comprises an expulsion fuse tube 26 provided with an upper terminal or contact 2l and a lower terminal cr contact 28.

The contacts 2l and 28 are adapted to engage` with terminal or contact assemblies 3 and 4 respectively. Mounted within fuse tube 26 is the conventional fuse link 29 preferably of the button head type which is held in position in conducting engagement with the upper contact 21 by means of a cap 39 screwed to a threaded portion of contact member 21 which is fastened to the upper end of fuse tube 2G. As will be understood by those skilled in the art, fuse link 29 mounted within fuse tube 26 includes a flexible cable or conductor portion 3| connected to the lower terminal of a fusible element 32. In the drawings, except for the sectional views of Figs. 2 and 3, the flexible conductor 3| is the only visible portion of the fuse link. The fuse link 29 also includes a small tube 33 enclosing the fusible element 32. It will be understood that the fuse device including fuse tube 25 and fuse link 29 operates on the expulsion principle to interrupt the electric circuit therethrough by expelling gases and fuse link parts through the open lower end of expulsion fuse tube 26.

The upper end of fuse tube 26 is secured to cover 2| by means of a metal support 34 having an opening therethrough through which the cap 38 of the fuse holder may be inserted. The enlarged portion of contact 21 will not pass through the opening in metal support 34 thereby preventing substantial longitudinal movement of the fuse tube 26 as a result of recoil upon rupture of fusible element 32. Metal member 34 is fastened to the upper portion of door or cover 2| by any suitable means and may include a spring member 35 to firmly connect electrical contact 21 and metal member 34. The lower portion of fuse tube 28 is held to door 2| by means of a spring clip 36 fastened to the inner side of door 2|. Spring clip 36 is preferably also provided with a metal member similar to 35 to electrically connect it with lower contact 28 or else is positioned so that it electrically engages lower contact 28.

The lower contact 28 is constructed in a manner very similar to that disclosed and claimed in Hermann Patent 2,335,062, granted November i 23, 1943, and assigned to the same assignee as the present application. As described in the Hermann patent, terminal 28 preferably comprises a formed stamping somewhat U-shaped with right angles at the base of the U so that the sides of the U furnish a rectangular contact for engaging lower terminal clip 6, as is clearly shown in Fig. 3. rEhe fuse tube 26 is provided with a recess 31 best shown in Fig. 2 for accommodating a key which is illustrated as a bolt 38 having a head 39 which is shaped so that it will not turn when inserted in the recess 31 of fuse tube 28. AS illustrated, head 39 is rectangular in shape. Bolt 38 is adapted to be inserted through an opening 40 in terminal 28 whereupon terminal 28 is slipped over fuse tube 26 so as to partially encircle it with the key comprising head 39 of bolt 38 inserted in recess 31 of fuse tube 26, whereby longitudinally to position contact 28 on fuse tube 2B. The arms of the U- shaped stamping 28 are then bent or clamped around fuse tube 25 to assume the rectangular shape clearly shown in Fig. 3 whereupon the key comprising bolt head 39 is maintained in recess 31 and terminal 28 is fastened to fuse tube 26 in a simple and yet in a very effective manner.

Bolt 33 provides a convenient means for attaching the flexible conductor 3| to contact 28. I provide a knurled nut 4| having an undercut portion 42 so that a washer 43 may be rotatably attached to nut 4| as by wing members 44. The washer is rotatable relative to nut 4| and consequently will remain stationary when it frictionally engages flexible conductor 3| of fuse link 29. The method of fastening the lower contact 28 to fuse tube 26 described above, enables contact 28 to have a slight floating action on fuse tube 26 to insure good contact alignment between contact 26 and terminal or contact clip 6.

In order to prevent the insertion of fuse tube 26 into supporting clip 35 in any but the correct position, contact 28 is provided with a downwardly projecting lug 45, incorrect positioning being rejected by spring clip 36 which interferes with lug 45 in any but the correct position.

In order to prevent the flexible cable portion 3| of fuse link 29 from unwinding and coming free of .clamping nut 4|, contact 28 is provided with a pair of bosses 4B clearly shown in Figs. 1 and 4. When the fuse holder 25 is mounted on door 2| in the manner indicated in Fig. l the door is held in the closed and latched position by means of the contact clip 6 of upper terminel or contact assembly 3.

Since the fuse holder 25 is completely enclosed in housing it would be desirable to provide indicating means for indicating to a. lineman that the cutout has operated. Such cutouts are usually mounted on poles and indicating means therefore should be visible to some one standing on th'e ground. In accordance with my invention I provide an indicating means comprising an insulating sleeve 41 preferably colored red or some other readily discernible color, which insulating sleeve 41 is adapted to be slidably mounted over the lower end of fuse tube 2S below contact 28. Indicating sleeve 41 is provided with an upper circumferential flange 4B which fits around fuse tube 26. The inner diameter of sleeve 41 is somewhat larger than the outer diameter of fuse tube 2B so that a coiled tension spring 49 may be accommodated in the annular space between fuse tube 26 and indicating sleeve 41. The upper end 59 of tension spring 49 is adapted to be inserted in an opening 5|, see Fig. 1, in indicating sleeve 41 thereby fastening one end of spring 49 to indicator 41. The lower end of fuse tube 26 is provided with an annular groove 52. The portion of coiled spring 49 adjacent annular groove 52 is provided with a turn or two 53, of a slightly reduced diameter so as to fit into groove 52. Reduced diameter turn 53 is connected with a turn or two 53 of the same diameter as the main part of spring 49 but displaced somewhat therefrom by a portion 54 extending along the axis of fuse tube 26 and adapted to fit into an axial notch or recess, as is obvious from Fig. 2. With this arrangement it is clear that the lower end of spring 49 is fastened to fuse tube 26. Spring 49 tends to move indicator 41 downwardly to the dotted position indicated in Fig. 1. Normally the indicator 41 is held in th'e non-indicating position by means of flexible cable 3|, as is shown in Fig. 2, the lug 45 of contact '28 limiting the upward movement thereof.

I have found that the spring 49 arranged in the annular space between fuse tube 36 and indicator sleeve 41 performs a very essential function in that it acts as a baffle so that gases expelled from the lower end of fuse tube 26 cannot blow up between sleeve 41 and fuse tube 26, the circumferential flange 48 and spring 49 effectively preventing this. In prior art arrangements failure of the cutout occurred by virtue of th'e fact that the hot arc gases could flow upwardly.

-In .accordance with my invention vthe turn or turns 53'. of spring49 are electrically engaged by flexible conductor 3|...thereby avoiding any capacity eifect ywith spitting or corona. Also the turn or turns 53 eifectivelyfguide indicator 41.

InL Fig. 5 I have illustrated a modification of the arrangement for fastening the iiexible conductor orcable portion of the fuse link to the lower Contact ofV th'e fuse holder. yThis lower contact is'designated by the referencek numeral 55. Lower contact 55 is substantially identical with lower contact 28 of Fig. 2. However the opening in contact 55 Vcorresponding to the opening 40 of contact 28 is threadedso as to receive the screw 56 which is `also adapted to be inserted ina cooperating recess in fuse tube 26 thereby positioning and fastening lower terminal to fuse tube 26. Slidably mounted on screw 56 are a plurality of dish-shaped washers 51, 58 and 59 and a compression spring 60. The compression spring ,60 ,pushes the washers against each' other andagainst the contact 55. Dishshaped washer 59 is adapted to have its contact surface held against contact 55 b-y spring 60. Dish-shaped washer 58, on the other hand, is arranged on screw 56 in opposed relationship to washer 55 and is adapted with washer 51 to provide a pair of contacting surfaces therebetween. With th'e arrangement described, the iiexible cable portion 3| may merely be wrapped around pin 56 one or more times with the cable being held as is clearly shown in Fig. 5, between contact 55 and washer 59, and if a second turn h around pin 56 is desired between washers 51 and 58. A pin El extending from contact 55 or from a lug 62 attached to contact 55 prevents crossing of the flexible cable 3l. It will be observed that with the arrangement disclosed in Fig. 5 putting in a new fuse link is a very simple matter.

While I have shown and described what I at present consider th'e preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modications may be made without departing from my invention, and I, therefore, aim in the appended claims toy cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an electric circuit interrupter, spaced line terminals, a fuseholder provided with contacts arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contacts and h'aving a flexible lead portion extending out of said fuseholder to be connected to one of said contacts, means for indicating operation of said fuse link comprising an insulating sleeve slidable on the lower end of said fuseholder and adapted to be held in the non-indicating position by said flexible lead portion, and spring means enclosed within said indicator sleeve for biasing said indicator to its indicating position.

2. In an electric circuit interrupter, spaced line terminals, a fuseholder provided with contacts arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contacts and having a flexible lead portion extending out of said fuseholder to be connected to one of said contacts, means for indicating operation of said fuse link comprising an insulating sleeve slidable on the lower end of said fuseholder and adapted to be held in the non-indicating position by said, flexible` leadporf tiornand .spring means enclosed within said inw dicator sleeve for biasing said indicator ytoits indicating position, said spring means being arl ranged to electrically engageA said flexible lead portion.

3. In an electric rcircuit interrupter, spaced line terminals,l a fuseholder provided with contacts arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contactsand having a flexible lead portion extending out of said Yfuseholder to be connected to one ,of said contacts, meansfor indicating oper-A ationof said fuselink comprising an insulating sleeve slidable on ,the lower end of said fuseholder and adapted to be held in ther nonfindieatingv position by said flexible lead portion, and spring means enclosed within an annular space dened. by said indicator sleeve and said fuseholder for biasing said indicator to its indicating positiomsaid spring means acting as a bale to prevent hot arcgases from passing through saidannular space.

4. In an electric circuit interrupter, spaced line terminals, a fuseholder provided with contacts arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contacts and having a flexible lead portion extending out of said fuseholder to be connected to one of said contacts, means for indicating operation of said fuse link comprising an insulating sleeve slidable on the lower end of said fuseholder and adapted to be held in the nonindicating position by said flexible lead portion, a circumferential flange on said sleeve, and spring means enclosed within an annular space defined by said indicator sleeve and said fuseholder for biasing said indicator to its indicating position, said spring and said flange substantially preventing hot arc gases from passing through said annular space.

5. In an electric circuit interrupter, spaced line terminals, a fuseholder provided with contacts arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contacts and having a flexible lead portion extending out of said fuseholder to be con nected to one of said contacts, means for indicating operation of said fuse link comprising an insulating sleeve slidable on the lower end of said fuseholder and adapted to be held in the nonindicating position by said flexible lead portion, spring means enclosed Within an annular space defined by said indicator sleeve and said fuseholder for biasing said indicator to its indicating position, and means for fastening one end of said spring means to said fuseholder comprising a groove on said fuseholder and a turn of reduced diameter on said spring means to engage said groove.

6. In an electric circuit interrupter, spaced line terminals, a fuseholder provided with contacts arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contacts and having a flexible lead portion extending out of said fuseholder to be connected to one of said contacts, means for indicating operation cf said .fuse link comprising an insulating sleeve slidable on the lower end of said fuseholder and adapted to be held in the non-indicating position by said flexible lead portion, spring means enclosed within an annular space defined by said indicator sleeve and said fuseholder for biasing said indicator to its indicating position, means for fastening one end of said spring means to said fuseholder comprising a groove on said useholder and a turn of reduced diameter on said spring means t0 engage said groove, and means for fastening the other end of said spring means to said sleeve.

7. In an electric circuit interruptor, spaced line terminals, a fuseholder provided with contacts arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contacts and having a flexible lead portion extending out of said iuseholder, means for fastening said flexible lead portion to one of said contacts on said fuseholder comprising a pin extending from said one contact, a plurality of dishshaped Washers on said pin, and spring means on said pin for biasing said Washers together so that said flexible lead portion may be Wrapped around said pin and held between said washers.

8. In an electric circuit interruptel, spaced line terminals, a fuseholder provided with contacts 20 arranged to engage said terminals, a fuse link in said fuseholder electrically interconnecting said contacts and having a exible lead portion extending out of said fuseholder, means for fastening said flexible lead portion to one of said contacts on said fuseholder comprising a first pin extending from said one Contact, a plurality of dish-shaped Washers on said pin, spring means on said pin for biasing said Washers together so that said flexible lead portion may be Wrapped around said pin and held between said Washers, and a seco-nd pin extending from said one Contact for preventing crossing of said flexible lead portion when Wrapped around said first pin.

RALPH S. BENNETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,135,789 Birkenmaier Nov. 8, 1938 2,264,320 Schultz June l1, 1940

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