US2328745A - Circuit breaker - Google Patents

Description

p 7, 1943- J.-SANDIN 2,328,745

CIRCUIT BREAKER Filed Sept. 19, 1939 4 Sheets-Sheet 1 INVENTOR k/0fl7660/7040.

I BY 62 ATTdRNEY "Sept..7, 1943- J. SANDIN CIRCUIT BREAKER Filed Sept. 19, 1939 4 Sheets-Sheet 2 INVENTOR jrome 50/70 70. @0 1 9J ATTORN EY WITNESSES: W fi 0.1% v

P 1943- J. SANDIN 2,328,745

CIRCUIT BREAKER Filed Sept. 19, 1939 4 Sheets-Sheet 4 .n R d Y 05 2 2% m MUM 0mm W700 W 5 m m m W 3 5 0 Y 6 vfi 1 W .MBM M d Fl M W L %W 3 H 6 w A HJMZ Z -LMV T w M T 5 4 Fm 0 a 8 I- III 9 n :1 Q a B Z 00 m7 4 m 7 00 G Patented Sept. 7, 1943 CIRCUXT BREAKER .ierome Sandin, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 19, 1339, Serial No. 295,565

8 Claims.

My invention relates generally to electric circuit interrupting devices, and more particularly to interrupters of the type designed to automatically open a circuit in response to the passage there-- through of currents of a predetermined magnitude, and then drop out of the circuit, to insert a relatively large air gap, and at the same time rovide a readily visible indication of the ccndition of the device.

In the preferred form of my invention, which I disclose herein, the circuit interrupting device is in the form of a high voltage fuse, of the type commonly referred to as a drop-out fuse.

Fuses of this type have been used heretofore, however, they have been of complex form, requiring, in addition to movable mechanism on the fuse proper, various complex latch mechanisms on the fuse or support, to maintain the same in position, or relatively complicated linkages for supporting the fuse.

Accordingly, it is an object of my invention to provide a circuit interrupting device, which is adapted to automatically interrupt a circuit upon the'passage therethrough of currents of a predetermined magnitude, which includes means to enable the same to drop out of its associated circuit when supported in association therewith by relatively simple supporting means, which supporting means can be economically manufactured as a standard type of fuse support for other types of fuses, for example, a simple disconnecting fuse.

A further object of my invention is to provide a high voltage fuse embodying separable parts which are movable in response to blowing of the fuse to release the fuse from its support.

Another object of my invention is to provide a tubular interrupter casing with separable parts, at least one of which is movable in response to an interrupting operation of the interrupter, to releas the interrupter and casing from engagement in a circuit.

A still further object of my invention is to provide a movable interrupter terminal having novel cooperation with its cooperating contact.

Another object of my invention is to provide a high voltage fuse which is movably supported in engagement with a simple contact clip, and wherein the fuse is constructed to be disengaged from said clip in response to blowing of the being flared outwardly as at 2B.

in Fig. 1;

Fig. 4 is a partial vertical sectional view through a portion of the fuse tube shown in Fig. 1; I

Fig. 5 is a side elevational view similar to Fig. 1, but showing another embodiment of my invention;

Fig. 6 is atop view of the device shown in Fig. 5;

Fig. 7 is a bottom View of the device shown in Fig. 5;

Fig. 8 is a vertical sectional view of the upper end of the fuse shown in Fig. 5, showing a portion of the upper contact and contact spring in elevation, and

Fig. 9 is a vertical sectional view of the upper end of a fuse like that shown in Fig. 8, but illustrating a modified means for securing a fuse link to the upper fuse cap. I

In the embodiment of my invention shown in Figs. 1 to 4, inclusive, I have provided a supporting insulator 2 which is supported intermediately thereof by the supporting clamps 4 which are bolted to a bracket 8, adapted to be secured to a cross arm or other support. An upper contact clamp 8 is secured to the upper end of the insulator 2 for supporting the upper fuse contact [2. The upper contact l2 and an upwardly extending contact terminal portion IS, are secured to the upper, contact clamp 8, as by the bolt and nut l4 extending therethrough. lead [8 is adapted to be connected to the terminal portion It, for example, as by the bolt and nut M. The upper contact I2 includes th substantially U-shaped conducting clip 22 (Fig. 2), havin its base secured to the upper contact clamp, and having its intermediate side portions bowed outwardly as at 24, with the free ends of the clip A U-shaped resilient spring 28 is fitted over the inner end of the conducting clip 22, with its base secured to the upper contact clamp 8 by the bolt M, and has the outer ends of its leg portions engaging the bowed portions 24 of the conducting clip, to exert a resilient pressure thereon.

A lower contact clamp 33 is secured to the lower end of the insulator 2 and has secured to its outer forward end a stop bracket 32, having a forwardly bent lower end 34 to form a stop portion for a purpose to be hereinafter described. Also secured to the outer end of the lower contact clamp 33 are the contact members 35 and 33 and a contact terminal 33. These parts (Fig. 3) are secured to the lower contact clamp 33 by the bolt and nut 40. The contact members 35 and 38 re substantially U-shaped in form, with th outer ends of the leg portions of the U curved inwardly, and with the member 38 nested within the contact member 35, so that the curved ends of the leg portions of the contact members 35 and 38 are positioned to engage a fuse terminal at different portions thereof. The contact terminal 33 is adapted to have a lead 35 secured thereto, as by the bolt and nut 31. Secured to opposite sides of the lower contact clamp 30, as, for example, by the rivets 42, are a pair of hinge plates 45. forwardly from the lower contact clamp 39 and terminate at their forward ends, in lower hooked crtions 3, for pivotally r ceiving fuse trunions, and have upper inclined guide surfaces preferably of fibre, or at least the inner surface 3 thereof being of fibre, or of any other suitable material which is capable of evolving an arcestinguishing gas when in proximity to an electric arc. The fuse tube 52 is provided with an usper terminal cap 54 secured over the upper end of the tube, and adjacent to, but spaced from the lower end of the tube, there is secured a collar (Fig. i) for anchoring a spring hous- 53 relative to the tube. The collar is secured to the tube in any suitable manner, such, for example, as by having an indented portion 51 engaging the material of the tube wall. A coil spring 32] is provided in the spring housing 53 and engages at its upper end with the inner side of the upper wall of the spring housing, and engages at its lower end with a lower terminal sleeve Cc which is telescoped over the lower end of the fuse tube in a manner to be freely slidable thereon. The lower terminal sleeve 62 is maintained in position on the fuse tube to compress the spring 60 by the fuse link, which includes an upper fusible portion 64 having one end secured to the upper terminal cap 54 as by the rivet B8, and having its other end secured to a flexible conductor GB in any desired manner, such, for example, as by soldering. The flexible conductor 53 may be of any desired conducting material such as copper or the like. The conductor 68 extends through the fuse tube and out the lower thereof, and is secured to the lower terminal sleeve 62 by the knurled nut 13. The lower terminal sleeve 62 is provided with oppositely projecting trunnions 12 which, as shown, are substantially semi-cylindrical in shape to cooperate with th hook portions 46 of the hinge plates M and with the inclined guide surfaces 38 thereof, to permit removal of the trunnions, and consequently the fuse, but only when the fuse is in a depending position inclined substantially at a 45 angle forwardly of the vertical.

These plates extend downwardly and or guiding the trunnion into the bight of Adjacent the upper end of the fuse tube there is provided a strap member 14 which surrounds the tube and has its free ends secured together in clamping relation with the tube by the bolt and nut 18, with the free ends of the strap member enlarged and extending forwardly, and provided with apertures as at 18 to provide a means for moving the fuse into and out of engagement with the contacts, as, for example, by the use of a hook stick operating member.

In the operation of this embodiment of my invention, and as described heretofore, the fuse link normally maintains the spring 60 between the fuse tube and the lower terminal sleeve 62 in compression so that the fuse link is maintained under tension. As shown in Fig. 1, the fuse 50 i pivotally movable about its trunnion 12 from an open position to its closed position shown in Fig. l, where the terminal sleeve 52 engages the lower contacts 36 and 38, and the upper terminal of the fuse engages the upper contact I 2 in the bowed portions 24 thereof to maintain the fuse in the closed position. Inward movement of the fuse beyond this position is prevented by bolt M on contact I2, and the stop 34 also limits inward movement of the fuse when the top cap is in the dotted line position shown in Fig. 1, and also when the upper end thereof fails to enter the upper contact. The lower contacts 35 and 38 are of a resilient conducting material and are arranged to be compressed or stressed by engagement with the lower terminal sleeve 62 when the fuse is in the closed position shown in Fig. 1. In this position the lower contacts constantly exert a pressure on the lower terminal sleeve 62 outwardly, in a direction tending to rotate the fuse 50 in a clockwise direction about its trunnions 12.

As stated above, however, the fuse is maintained in the closed position shown in Fig. 1 by engagement with the upper resilient contact I2. When the fusible portion 64 of the fuse link is melted, which will occur upon the passage through the fuse of currents of a predetermined magnitude, an arc will be formed between the upper fuse terminal and the flexible conductor 68 which will play on the inner walls of the fuse tube 52, causing the evolution of relatively large quantities of arc-extinguishing gas from the material of the fuse tube. This gas will be expelled from the lower end of the fuse tube with an expulsion action, which will result in a reaction force tending to move the upper end of the fuse upwardly. This reaction force, coupled with the force exerted by the spring 60 is sufficient to move the entire fuse tube 52 with its upper terminal cap 54 to the dotted line position shown in Fig. 1, even under severest conditions of corrosion or snow and sleet. The spring, however, is strong enough to normally accomplish this movement of the fuse tube by itself. Obviously, this movement of the fuse tube will separate the fused portions of the fuse link, and this, coupled with the action of the arc-extinguishing gas, will insure circuit interruption before the upper fuse terminal leaves the upper contact.

When the upper fuse terminal cap reaches the position shown in dotted lines in Fig. 1, the lower resilient contacts 36 and 38 are then free to move the fuse 50 in a clockwise direction about its trunnion 12, to move the fuse terminals away from the contacts so that the fuse drops out of its associated circuit, and if its motion is not stopped, it will move to a depending vertical position. The upper contact l2 does not impede this motion because the space between the spaced conducting side portions 24 of this contact in their normal positions, is greater than the diameter of the fuse tube. Hence, when the upper fuse terminal is projected above the contact I2, the contact no longer exerts any restraining function on the fuse 50.

In the embodiment of my invention illustrated in Figs. to 8, I have shown an insulator 80 which is supported intermediate of its length by supporting brackets 82, which, in turn, are bolted to a cross arm supporting bracket 84, adapted to be secured to a cross arm or other suitable supporting means. An upper contact clamp 88 is secured to the upper end of the insulator 80, T;

and has secured to its forward portion as by the bolt and nut 96, one leg of a U-shaped vertical spring member 90, an upper contact member 92, and a contact terminal portion 94 which projects upwardly from the upper contact. The terminal portion 94 is adapted to have a lead 98 secured thereto as by the bolt and nut I00. The upper contact includes a substantially U-shaped conducting clip I02 (Fig. 6), having its base portion traversed by the bolt and nut 96, and having n its leg portions extending forwardly with the intermediate portions thereof bowed outwardly as at I04, and with the free ends of the legs flared outwardly as'at I09. Fitting about the inner end of the conducting clip I02 is a U-shaped spring I00, likewise having its base portion traversed by the bolt 95, and having the ends of its leg portions engaging the ends of the bowed portions I04 of the conducting clip I02, to exert resilient pressure thereon. The upper contact spring 00 has a second vertically extending leg portion IIO disposed between the legs of the U-shaped contact clip I02, so that it may engage the upper terminal of a fuse whose upper terminal is in engagement with the upper contact 92.

A lower contact clamp H2 is secured to the lower end of the insulator 80 and has secured to its forward end, as by the bolt and nut H8, a lower contact terminal H4 and a lower contact H6. The lower contact IIS includes a substantially U-shaped conducting portion (Fig. '7) made of suitable conducting material, such, for example, as copper or the like, with the outer ends of the legs of the U-shaped portion, being bent inwardly as at I20. Nested within the conducting member H5, is a substantially U-shaped spring I22, having the base thereof traversed by the bolt H8, and having the free ends of the leg portions thereof engaging the inwardly bent portions I of the U-shaped conducting portion. The lower contact terminal portion H4 is adapted to have a lead I24 connected thereto as, for example, by the bolt and nut I26. Secured to the sides of the lower contact clamp I i2 are opposed hinge plates I28, which may be secured to the opposite sides of the contact clamp I I2 in any suitable manner, such, for example, as by the rivets I29. The hinge plates extend downwardly and forwardly from the contact clamp H2 and terminate in lower hooked portions I for pivotally receiving a fuse trunnion, and have an upwardly and forwardly inclined guide portion I32, for guiding the fuse trunnion into the hook portion I30.

The fuse I34 which I have illustrated in connection with this embodiment of my invention includes a fuse tube I35 of suitable insulating material, preferably of fibre'or other insulating material capable of evolving an arc extinguishing gas, like the fuse tube 52. To the upper end of the fuse tube I36 there is secured an upwardly projecting sleeve I 38 (Fig. 8), having an enlarged lower socket portion I 40 secured to the upper end of the fusetube I36, as, for example, by crimping or the like. An upper terminal cap member I42 is provided over the sleeve I38 to enclose a coil spring I44, with the upper end of the spring engaging the inner surface of the top cap wall, and having its lower end engaging the shoulder I43 formed on the sleeve I38. The upper end of the coiled spring I44 may be secured to the cap I38 as, for example, by the indented portions I46 on the cap engaging between the coils of the spring. This indented portion I46 may be in the form of screw threads. Obviously, it is immaterial whether the spring I44 be secured to the cap I42 or to the sleeve I38. The upper terminal cap I42 is provided with an aperture in its top wall I40 for anchoring the fusible portion I50 of the fuse link to the cap as, for example, by soldering the same. The other end of the fusible link IE9 is suitably secured to a flexible conductor I52 in any desired manner, such, for example, as by riveting or soldering, and the flexible conductor I52 maintains the spring I44 compressed, inasmuch as the conductor extends down through the fuse tube and out the open end thereof to be anchored to the lower fuseterminal I54 by the knurled nut I62.

The lower fuse terminal I54 is in the form of a metal strap disposed about the lower end of the fuse tube with the free ends thereof brought together and securely clamped as by the bolt and nut I55, to anchor the sleeve on the fuse tube. The lower terminal sleeve includes an upwardly extending portion I58, at the rear side of the fuse, which terminates in forwardly extending, outwardly flared, terminal parts Hi0, positioned to engage the inwardly turned ends of the lower contact I20 when the fuse is in the closed position. The lower terminal sleeve of the fuse is also provided with opposite, outwardly projecting trunnions I63, for pivotally engaging the hooked portions of the hinge plates I28, respectively.

As shown in Fig. 5, the trunnions I33 are rectangular in cross section to prevent withdrawal of the trunnions from the hinge plates, and hence removal of the fuse from its support, until the fuse attains a depending position slightly inclined forwardly from the vertical. Adjacent the upper end of the fuse there is secured a strap member IE4 having one end surrounding the fuse tube and bolted to an intermediate portion of the strap, as by the bolt and nut iES, and having its opposite end enlarged and apertured as at I68, for reception of an operating such, for example, as a hook stick operating member.

The operation of this form of my invention is much like that of the first embodiment. Here the fuse link maintains the spring I44 compressed in the normal position of the fuse when the fuse is in the closed position as shown in Fig. 5. The U-shaped spring associated with the upper contact is maintained stressed so as to constantly exert a force on the fuse tending to move the same outwardly away from the contact, and in a clockwise direction about its trunnions I63. Likewise the lower contact H6 has the spring I22 thereof, slightly stressed by engagement of the lower fuse terminal when the fuse is in its closed position, to augment the action of spring 90. The fuse is, of course, held in the closed position by engagement of the upper terminal cap with the bowed portions I 04 of the upper contact clip. When the fuse blows, the fuse link releases the compressed spring I44, which, together with the reaction caused by the expulion action of gases flowing out the lower end of the tube, moves the upper fuse terminal cap I42 upwardly above the upper contact 92 to the position shown in dotted lines in Fig. 5, to separate the fused portions of the fuse link to draw out the resulting arc and aid in its extinction. When the fuse terminal cap I42 attains this position, the fuse is then free to move under the influence of the upper contact spring 90 and the lower esilient contact H6 in a clockwise direction, away from the contacts, and about its trunnions I63, to drop out of the circuit to a depending vertical position. As in the first embodiment, spring I44 is strong enough to normally release the upper fuse terminal from its contact, this action is enhanced, however, by the expulsion action of the fuse.

\Vhen it is desired to re-fuse the fuse shown in this embodiment of my invention, the upper terminal cap is removed, if it has not been blown off, and a new cap provided with a spring similar to spring I44 and a new fuse link may be substituted therefor. The fuse link is extendd downwardly through the fuse and the lower end thereof may be pulled through to compress the spring 5 14, whereupon the lower end of the fuse link may be secured to the lower fuse terininal by the nut I62. As stated above, the spring might be secured to the sleeve I38 at the upper end of the fuse instead of the terminal cap, in which event removal of the terminal cap would leave the spring intact and permit of the same sprin Similarly, to permit the use of a standard fuse link assembly of the type embodying an upper flat terminal head, the spring i 35 could be secured to the sleeve I38 as well as to the terminal cap, and a separate cap would be threadedly engaged with indentations I46 to secure such a fiat fuse link terminal b tween the two caps. A structure such as this is c "l in Fig. 9 of the drawings, wherein the 11d of coil compression spring I54 is shown as being angularly directed as at I19, so that the ou passes through an aperture at the lower end of sleeve 538. This serves to anchor the lower end of spring I41 to sleeve I33, 2.; as eviously described, the upper end of the s mg is anchored to cap I42 by the indentatio 5 I55. According to this embodiment of my .-ntion, the fuse link I55 is provided with a c-like head I'M rigid therewith, and which is dapted to be seated on the closed end of cap -32, and be secured in this position by an auxiliary cap HG engaging the reduced upper end of cap I42, and finding threaded engagement with indentations i 18. ObVlOllSlj, in this form of my invention, the cap IE2 is secured to th fuse tube ieby spr' 1g I44, and the only part w h needs to be replaced when the fuse blows is t fuse link including the disc-like head I76, tli

It should be obvious that I have provided the two embodiments of my invention disclosed, a relatively simple type of fuse which is constructed with a movable terminal portion adapted to move in response to blowing of the fuse to disen age itself from its associated contact, and permit the fuse to be moved away from the tact and drop out to an open cl'cuit p0 It should also be obvious that I have provi ed a fuse of novel form, which is adapted to be mounted in relatively simple supporting structure and which is also adapted for cooperation with relatively simple yet efficient contact structure.

l uses It should also be apparent that I have provided a fuse having novel movable terminal structure which, in at least one instance, embodies a simple but convenient fuse refill element.

Having described preferred embodiments of my invention in accordance with the patent statutes, I wish it to be understood that I do not desire to be limited to the particular embodiments disclosed herein, inasmuch as it will be obvious, particularly to persons skilled in the art, that many changes, modifications and substitutions may be made in the particular structure disclosed without departing from the broad spirit and scope of my invention. Therefore, I desire that my invention be limited only by what is expressly set forth in the appended claims.

I claim as my invention:

1. In a circuit interrupting device, means for automatically interrupting a circuit in response to the passage therethrough of currents of a. predetermined magnitude, a tubular enclosure therefor including a freely removable terminal cap, resilient means secured to said cap and freely engaging said enclosure and held under stress by said interrupting means, whereby said cap is moved relative to said enclosure in response to operation of said interrupting means.

2. In a fuse, a fuse tube embodying relatively freely separable tubular parts, a fusible element adapted to be inserted in said tube and electrically connected to terminals on said parts, means for separating said parts when the fuse blows, said means being secured to and housed by at one of said parts.

A fuse refill, including a flanged terminal cap having one end of a fuse link and a compressible resilient means secured therein.

4. A fuse refill, including a flanged terminal cap having one end of a fuse link secured in the cap, and a coil spring secured in the cap and extending from the open end thereof substantially concentrically with respect to the cap and link.

5. In a circuit interrupting device, a movably mounted elongated interrupter casing having a terminal movable with said casing into and out of engagement with a resilient contact clip, resilient means in said clip so as to be stressed when said terminal is engaged with said clip, and means for moving said terminal laterally relative to said clip for releasing said terminal from said clip in response to an interrupting operation of said interrupting device to permit said resilient means to move said casing and terminal away from said clip.

6. A refill unit including a flanged terminal cap adapted to have one end of a fuse link secured therein, and compressible resilient means also adapted to be secured in said cap independently of said fuse link.

7. In a fuse, tubular supporting means of conducting material adapted to be pivotally mounted, a fuse tube of insulating material slidably mounted in said tubular means, terminals on said fuse tube and tubular means, respectively, resilient means engaging said tube and tubular means to bias said tube for movement in a direction to longitudinally separate said terminals, and fusible means adapted to connect said terminals and maintain said resilient means in a stressed condition.

8. In a. circuit interrupter, spaced line contacts, tubular terminal means mounted for pivotal movement into and out of engagement with terminal means to normally prevent relative movement thereof so as to maintain said terminal and terminal means in engagement with said c0ntacts, respectively, whereby upon fusion of said fusible means said terminal is moved away from said terminal means and out of engagement with its respective contact.

JEROME SANDIN.

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