US2284845A - Repeating fuse - Google Patents

Description

June 2, 1942. H. L. RAwLlNs Erm..

REEATING FUSE Filed NOV. 29, 1955 2 Sheets-Sheet l rm E S S E N T.. MJ.

ATTRNEY June 2, 1942. H. L, RAwLlNs ETAI.-

REPEATING FUSE 2 Sheets-Sheet 2k Filed Nov. 29, 1935 y nw@ Chu ATTORNE Patented June 2, 1942 L UNITED STATE S PATENII OFFICE nErEA'nNG Fusi:

Application November 29, 1935, Serial No. 52,098

(Cl. o-126) 11 Claims.

This invention relates to multiple unit circuit interrupters and specifically to circuit interrupters ofthe type in which a fuse tube is released and falls to a conspicuous position when the fuse is blown. In one form of the circuit interrupter to which this invention particularly appertains,

a plurality of expulsion fuse units are used, the blowing of the ilrst fuse causing the second to be connected in the circuit and so on. The inven- -tion=herein described is particularly related to the mechanism for establishing the connection through the second fuse when the ilrst is blown. The mechanism by which the fuse is released when the fuse is blown is the subject of the pattent to Herbert L. Rawlins, Patent No. 2,183,083, issued December l2, 1939, and assigned to the assignee of this application.

When a conventional fuse is blown on a power line, an attendant must replace it. In power lines through rural districts, it is desirable that the attendant be not required to visit the fuse locations often. Hence, it is the practice on such lines to provide a plurality o! fuses, preferably of the expulsion type due to the large arc extinguishing capacity of those devices, which can vide a simple means for resetting the transfer mechanism when the fuse tube is reset.

It is a further object of this invention to provide the needed delay in the transfer mechanism andvyet to limit the interruption of service to a short interval, say one second.

Other objects of the invention will be apparent from the following description and the accompanying drawings, in which- Figure 1 is a side elevation partly in section of the multiple fuse device.

Fig. 2 is a front elevation of the same.

Fig. 3 is an enlarged vertical section through the mechanism associated with the top of any one fuse tube, and

Fig. 4 is a similar section showing the mechanism in the position which it assumes after the fuse tube is blown.

serve in succession. Ii the first is blown during y a lightning storm some of the others may be blown during the same storm, but it is unlikely.

that all of them will be blown, and hence, some of the fuses will continue to serve until time for the next regular visit of the attendant.

It is an object of the invention to provide a mechanism for such automatic transfer of the connections to a new fuse tube.

It is an object of this invention to locate such mechanism for establishing the new connections at the top of the fuse tube. The tube being open only at the bottom, the mechanism is thus protected from the fumes expelled by the tube.

It is a further object of this invention to pro-A vide an interrupter of this type which shall include a suitable housing for the actuating mechanism therefor, in order to protect that mechanism from the Weather and from accidental or malicious interference with its operation.

It is a further object of this invention to provide a mechanism which is inherently capable of producing a suilicient delay during the reclosing operation to permit the fault to clear itself or the disturbance caused by lightning to cease and which, at the same time, includes means whereby the final movement oi the transfer mechanism shall be quick enough to insure well established contact.

It is a further object of this invention to pro- The device is mounted in any convenient way. As illustrated, it is mounted upon a cross arm I on a pole of the power line. A support from the cross arm holds an insulator 2. At its upper end the insulator has a supporting device l which holds a connecting bar 4 oi copper. A similar supporting device 5 at the bottom of the insulator holds a bar 6, also of copper.

The mechanism at the bottom of each fuse tube includes a dog It and a cooperating spring II which are described in greater detail in the above mentioned copending application. The tube I2,

-of which there are three shown, contains a fusible element which is connected by a conductor shown at I3 to a fastening upon the dos III. The spring I I acts to exert an upward thrust upon the tube I2 and so seats the cap I5 within a recess in the member 20. The cap I5 closes the upper end of the tube I2. I

A housing 22 is provided above the upper end of each tube I2. Preferably the housings are made of molded insulating material. The lower walls of the housings are relatively thin but the upper parts are thickened, the change in thickness being indicated at 23 and 24. The additional thickness at 24 provides two opposed ledges each of which is useful for receiving a boli; by which the housing is secured to the copper strip l. A.

notch in the shoulder 23 provides a seat for the pivot 25 of the member 20.'

The member 20 consists of two side plates each 33 which serve to stiften thefloor 29. The left-y hand portion of the notch 30 is shown as somel what oblique but it may, if desired, be made more nearly parallel to the side of the cap I5.

'It affords an abutment by'which the cap I5 may position the member 20.

The portion of the'bottom of the member 20 on the other side of the notch is provided upon the upper face with an eye 35 into which a spring 36 is secured. The other end of the spring 36 is fastened into a stirrup 31 which is 'secured in place by a binding post 39, extending Ato the outside of housing 22. The stirrup 31 has two arms, eachwith an eye. One eye receives the spring 36 and the other receives a spring 40.

A flexible copper conductor 4I, secured by binding post 39 between the two arms of the stirrup 31, connects the binding post 39 to the cross bar 28 of the member 28, and thus the fuse I2 is connected into the circuit through the cap I5 and the member 20. The cross bar 28 not only affords a convenient place to securev the `connector 4I but also strengthens the member 20. It is located at the bottom of a notch in each side member separating the pivotv 25 and that portion of the floor which carries the eye 35. The

tive housings is connected by one of the con` ductors 56 only toone of the contacts 55 which contacts are not electrically connected to the terminal strip 4 until after the associated fuse notches in the side members reduce their mass,

the moment of inertia of theA member 2U being thus kept as small as can conveniently be accomplished.

A cylindrical dashpot receptor 43 is molded vinto the upper portion of the housing 22. The receptor is lined with a brass sleeve 44 to afford good sliding surface for the dashpot piston 46. The sleeve may be omitted if desired. Although the fit is improved by means of the sleeve, there is sufficient leakage around thepiston 46, which is preferably formed of molded graphite or other suitable material, to permit the dashpot to move slowly.

A link 50 connects the dashpot piston46 with the lower end of the spring 40. This link Yis curved to the right (Fig. 3) at its lower end-in order to position that end at the right of the pin 26. This end of the link 50 receives the lower end of the spring 4D. 'Ihe cross pin 26 in the position shown in Fig. 3 is seated in the notch 5I in the link 50.

effecting this rotation The left-hand fuse F1g. 2) is normauytne rst to operate, and the conducting portions of the housing 22 associated therewith are con- `nected to the cross bar 4 by a strap connector 53. A binding post 54 affixed to the housing 22 associated with the first fuse is connected, by means of a copper link 56, with the binding post 39 of Vthe next housing, and a similar link 56 connects the binding post 54 of the second 'housing to the binding post 39 of the next housing and so on. The last housing has no binding post 54.

The ends of binding posts 54 inside the housings are equipped with contact blades 55 adapted to engage the end 58 of the floor of the member 20. This end 58 is shaped to slidingly enter between the contact blades and they are resilient enough to aiford good contact pressure.

has blown and the cooperating pivoted member 20 makes contact therewith.

In the operation of the device, when the current in the line exceeds a predetermined magnitude, either because of lightning or from an overload, short circuit or other cause, the fusible element Withinthe fuse tube I2 associated with the first housing is blown. As the link within this tube melts, the gases and fused metal' are expelled downward. They cannot escape upward because the cap I5 closes the tube at the top.

Before the fuse link is melted, it holds the conductor I3 from movement and this, as eX- plained in the above-mentioned copending application, holds the dog I0 against rotation. Because of the restraint upon the dog I0, the springr Il acts to press the tube I2 and the cap I5 upward. The pressure of cap I5 against the member 20 tends to produce clockwise rotation of that member (Fig. 3) about the pivot l25, thus resisting any tendency the spring 36 may have to move the member 20 counter-clockwise and also holding the dashpot piston 46 in its uppermost position by the pressure of pin 26 in notch 5I The conductor I3 being released by the fusion of the link, releases the dog IU 4and permits the spring II to rotate the dog relative to the tube I2 upon which it is supported. As a. result, the fuse moves downwardly so as to disengage the recess 30 in the member 20. As soon as the fuse disengages the member 20, the spring 36 rotates that member 20 counter-clockwise about the pivot 25. The force exerted by the spring 36 in lis opposed by the dashpot piston 46. This opposition continues and restricts the movement of the member ,2U to a speed fixed by the amount of leakage vin the dashpot until the cross bar 21 contacts with the link and moves it toward theleft in Fig. 3 suiliciently to release the cross pin 26 from the notch 5I. By this time, the line of action ofthe spring 36 has been moved well to the right of the i the dashpot piston occurs, the spring 36 rotates the member 20 rapidly in a counter-clockwise direction to bringthe terminal 58 into contact with the blades 55.

During all of this movement, the projections 3| on the two side plates restrain the link 50 from erratic movements. During the flrst part of the movement similar guidance is given by the flanges 33. Thus, the link 50, although pivcted at one end and held at the other by a long flexible spring, is prevented from getting out of place.

The connection from the binding post 39 of the left-hand housing is now through the flexible copper member 4I and the cross bar'28 to the floor of the member 20 and so to terminal 58 and the blades of the corresponding binding post 54. thence it is along the link 56 to the binding post 39 of the central housing. The circuit is thus established through the second fuse, the iirst fuse having swung to its normal open circuit position. When the second fuse is blown, the circuit is transferred in asimilar way to the third fuse. Any number of fuses may be provided, but for ordinary conditions, three would be suiiicient to assure continuity of service under ordinary operating conditions.

When the attendant visits the apparatus and discovers ythat a tube I2 is in open-circuit position, he may remove the blown unit, replace the blown fuse, and return the tube I2 to its vertical position, all by means of a suitable hook stick, the hook portion thereof being inserted in the ring 60. When a fuse is being swung from the open to the closed circuit position, it first contacts the left-hand side of the notch 30 which extends below the housing, as seen in Fig. 4. Movement of the fuse is thereby communicated to the member 20 and'that member is rotated clockwise from the position shown in Fig. 4 to the position shown in Fig '3 during the iinal stages of the movement of the fuse.

The spring 4t returns the dashpot piston 46 automatically to the illustrated position as soon as the pin 25 releases the link 50 during an opening operation.

During4 the use replacement operation, the

- clockwise movement of the member 20 causes the pin 26 to contact the edge of the link 5d and to move that link slightly to the left (Fig. 3), until the pin 28 enters the notch 5I. The movement of the link I) toward the left is opposed by the spring 40 and when the pin 26 has arrived at the notch 5t, the spring III causes the link to again move to the right, engaging the pin in the notch 5I, thus returning all of lthe parts to the position illustrated in Fig. 3. The apparatus is then restored to its normal operative condition and is ready to repeat the above described sequence of operation.

'I'he spring Ii, exerting pressure through tube I2 and cap I5, acts to hold the parts in the nor- ,mai operative position. Hence the device is automatically resettable. Further, since each of the switching members 20 automatically moves into engagement with the cooperating contact 56 as soon as the associated fuse operates or is manually swung to the open circuit position, thev structure automatically adjusts the electrical circuits through itself to assure proper sequential operation regardless of the position of the several fuse units.

The action of the'device after the first fuse I2 has blown should normally ocupy about a second. This is ample time for a fault to clear and for the gas to escape from the tube I2. The time interval may, however, be readily adjusted to any desired value by means such as the valve 10. Re-

gardless of the time interval, the final portion of the movement of the member 20 is so rapid that arcing is avoided at the contacts 55; this is an important feature of the invention and adds much to its reliability of operation,

Many variations in the structure will occur to those skilled in the art and we do not wish to be limited by the speciiic structure disclosed.

We claim as our invention:

l. In a circuit opening device, a plurality of expulsion fuses of the tube type, means for pivotally supporting each of said fuses at the lower end thereof, said means including a spring which exerts an upward thrust upon the fuse tube, and mechanism adjacent the upper ends of the tubes for operatively associating the fuses with the circuit in succession as each fuse is blown in turn.

2. In a circuit opening device, a plurality of fuses of the tube type, each pivotally supported at the lower end thereof, a separate mechanism adjacent the upper end of each of the tubes for operatively associating the fuses with the circuit in succession as each fuse is blown in turn, and a vseparate insulating housing for enclosing the A ing thefdelaying mechanism-to its original position upon said disconnection, said spring establishing reengagement upon return of the connector moving means to its original position.

4. In a circuit opening device, a plurality of fuse tubes, each containing a fusible element and each open at one 'end only, a separate housing disposed adjacent the yclosed end of each of said tubes, a mechanism in each housing, which includes a recessed member pivotally supported for movement between two positions, the closed end of the respective tube being receivable in said rccess of said pivoted member,` a spring, the line of action o which lies to one side of the pivot point of said member for biasing that member toward one of said two positions, said tube normally holding said member in the other of said two positions against the force exerted by said biasing spring means associated with each tube for moving it upon fusion of the element therein and thereby releasing the associated recessed member, and permitting said biasing spring to move said member to said other'position, a connector moved by the recessed member, and conductors cooperating therewith when said member has been moved to said other position vto connect a different fuse tube into the circuit.

5. In a circuit interrupter, a plurality of expulsion fuses, means for pivotally supporting each of said fuses at the lower end thereof, said support means including biasing means for exerting an upward thrust upon eachiuse, and mecha,- nism adjacent the upper ends ofthe fusesfor operatively associating the fuses with the circuit y in succession as each fuse is blown in turn.

6. A circuit interrupter comprising a plurality of drop-out fuse units, each unit comprising a fuse tube having a fusible element therein, a movable contact member, means biasing said tube into engagement with said contact member and to an open circuit position, said fusible element normally restraining said fuse tube from movement to the opencircuit position, a xed ycontact in circuit with an adjacent fuse unit, and

means for moving said movable contact member into engagement with said fixed contact upon the movement of said tube to the opencircuit position, following the fusion of said element for connecting an adjacent fuse element in the circuit.

7. In a circuit interrupter, a pair of terminal members insulatingly mounted with respect to each other in parallel vertical spaced relation, a plurality of fuse members pivotally supported mounted on the upper terminal member, a contact member in each of said housings normally adapted to releasably engage a fuse member, a connection from said upper terminalmember to thecontact member of the first housing for normally establishing a circuit through the first fuse member to the lower terminal member, and means including a mechanism withineach housing associated with the contact members for operatively connecting the fuse members in succession in circuit with said -terminal members as each fuse member is blown in turn. l

8. In a circuit interrupter, a plurality of exy pulsion fuses, means for pivotallyA supporting each of said fuses at the lower end thereof to enable thek fuse to swing to open and closed positions, a pivoted switch member adjacent the upper end of each of said fuses, each of said switch members having a recess in which the upperl end of a respective fuse is seated for normally holding said fuses against rotation about their pivotal supports, means -responsive to the operation of a fuse `for disengaging its upper end from the recess in its corresponding switch member, means for moving said switch members about their pivots in response to the operation of its respective fuse, and means engageable by a switch member upon movement thereof for establishing a circuit connectioxrt'o an adjacent fuse.

9i In a circuit interrupter, a fuse comprising a tube, a fusible element therein and means for moving said tube upon fusion of said element, a switch member normally in circuit with said fusible element, said switch member having a notch in which one end of said tube is seated for holding said tube in the closed position, means for moving said switch member upon fusion of said element and motion of said tube, means for retarding the, initial movement of said switch member, the nal movement of said switch member being completed with a snap action, and means engageable by said switch member upon the completion of its movement for establishing a new connection to the circuit. A

10. In a circuit interrupter. a fuse tube pivotaliy mounted at one end for swinging movement about its pivot to open and closed positions, va contact member movable betweentwo positions and normally held in one of said positions by said fuse tube for delivering current thereto, said ontact member holding said fuse tube against rotation about its pivot when said contact member is in said normal position, means'associated with said fuse tube which is operable when the fuse is blown to cause said fuse tube to release said contact member, means operable upon the release of said contact member to move said member to the `other of said positions, and a contact cooperating with said member when it has been moved to said other position for establishing a new circuit through thevinterrupter around the blown fuse.

11. In a circuit interrupter, a fuse tube pivotally mounted at one end for swingingmovement about its pivot to open and closed positions, a

' contact member movable between two positions and having a recess therein, said fuse tube being seated in said recess when in the closed position for holding said contact member in one of said positions and for holding said fuse tube against movement about its pivot, means responsive to the disengagement of said fuse tube from said re'- cess for moving said contact member to the other of said positions, means for retarding the initial movement of said contact 'memben the nal movement of said contact member being completed with a snap action, and means engageable by said contact member upon the completion of `its movement for establishing a new connection to th'e circuit.

I-(IERBERT- L. RAWLINS. ANDREW H. BAKKEN.

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