US2119388A - Electric switch - Google Patents

Description

May 31, 1938. 'B. R. HERMANN ELECTRIC .SWITCH Filed Oct. 6, 1933 Inventor Benjamin R Hermann,

34 mwv Hi Attorney.

Patented May 31, 1938 UNITED STATES ELECTRIC SWITCH Benjamin It. Hermann, Pittsfleld, Mass, assignor to General Electric Company, a corporation of New York Application October 6, 1933, Serial No. 692,414

15 Claims.

My invention relates to electric switches and more particularly to switches with fuses which are adapted to release the switch upon operation of the fuse.

In the protection of overhead outdoor transmission lines, it has become a common practice to combine a fuse with the line switch. For economy and safety it is desirable to locate the switch and the fuse combined with it near the top of the pole adjacent the transmission line. The opening and closing of the switch may be accomplished by a long switch stick with a hook adapted to engage the switch handle. However, examination of the fuse to determine whether or not it has operated and replacement of the fuse link is hazard-. ous due to theclose proximity of the live switch contact and transmission line. Combined switches and fuses have been provided with an arrangement for automatically opening the switch when the fuseoperates. In this manner the operation of the fuse is clearly indicated without the necessity of a close examination. The automatic opening of the switch has the additional advantage of removing the voltage stress from the fuse holder after the operation of the fuse. While the fuse is intact there is no voltage stress on the fuse holder. when the fuse has completed its operation before the switch begins to open no arc is drawn between the switch and contact. n the other hand, if the switch does begin to open before the fuse has completed its operation, an arc may be drawn between the switch and contact which will do serious damage to the fuse holder and fuse support and may require its replacement.

An object of my invention is to provide an improved switch and combined fuse which will insure a completed operation of the fuse before the switch begins to open.

Another object of my invention is to provide a fuse holder which may easilybe removed for the replacement of the fuse link and then replaced and reconnected in the circuit.

What I consider to be novel and my invention will be better understood by reference to the following specification andappended claims when considered in connection with the accompanying drawing in which Fig. 1 is a perspective view of .a-

combined switch and fuse in operative position; Fig. 2 shows a portion of the fuse holder and switch contact with a switch stick engaging thehandle to close the switch; Fig. 3 shows the fuse holder being removed for replacement of thefuse link; Fig. 4 shows the initial movement of the switch on operation of the'fuse link; and

Fig. 5 is a perspective viewon an enlarged scale of the switch handle.

Referring to the drawing, Ill indicates a cross arm secured to a pole, not shown, on which the transmission lines are carried. An insulator ll -5 is mounted on cross arm by means of a strap i2 and two-part clamp i3. Strap i2 surrounds a reduced central portion of insulator H and is secured to one part of clamp l3. Strap i2 is held in close engagement with insulator II by a bolt M. The two parts of clamp l3 are pulled tightly against opposite sides of cross arm ill which may vary in thickness by bolts l5. Upper switch contact I6 consists of a metal rod which extends about the upper end of insulator ii and seats in an annular groove H. The switch is guided to the contact surface of contact it by two flared ends l8 which form a V between them. Contact i6 is held in engagement with groove l'l bya combined clamp and connector I 9. Contact I6 is clamped between two parts and 2| of connector l9 by a stud 22. Stud 22 is provided with a longitudinal slot 23 in which a supply conductor 24 may be secured by a nut 25. Conductor 24 serves to connect contact ii to one of the overhead transmission lines. Lower switch contact 26 is formed of a metal rod which surrounds the lower part of insulator ii and seats in a groove 21. Contact 26 is held in position by a combined clamp and connector 28 which is similar to connector I! previously described. The contact surface of contact 26 is in the form of a pivot pin on which switch 29 is pivoted. A load conductor 30 is connected to contact 26 by means of connector 28. The general construction of the switch and support is not my invention, but is the subject of another application Serial No. 692,469 filed concurrently herewith in the name of R. S. Bennett and assigned to the same assignee to which this application is assigned.

Swltch." is provided with a fuse holder 3i consisting of a tube of insulating material in which-a fuse link 3| is carried. The upper end of fuse holder Si is closed by a contact cap l2. Cap 22 has a conical projection 33 which is adapted to be inserted between the two parts of contact II The shape of projection 33 is important becauae when it extends between the two parts of contact it it prevents the initial rotation of the fuse .holder 3| to delay the opening of switch 28 upon the operation of the fuse to permit theextinctionof the arc in a manner that will be described later. I Switch 2! is pivotally mounted on lower switch 66 contact by means of a toggle and fuse holder support 35. Toggle 3d and support are con-= nected by a pivot pin 36. The fuse link 3|! lo= cated in fuse holder 36 is connected to toggle El i by means of a thumb screw 3? and holds the toggle 34 in the closed position shown against the spring pressure of contact 06.

Toggle 343 is held with projection in engagement with fuse support 35 when fuse link ill is intact, fuse link 30 being securely fastened at its opposite end to fuse holder 3i. Thus a tension is transmitted through the fuse link ill to hold toggle 34 securely in position making switch 29 a single rigid structure which is adapted to pivot on lower switch contact 26. As long as fuse link 3| is intact, switch 29 operates as an ordinary disconnect switch and may be opened and closed in the usual manner by pivoting it about lower switch contact 26. As switch 29 is closed, conical projection 33 of contact cap 32 passes between the two projecting ends l8 of contact i6 separating the two parts of contact l6 until projection 33 nests in the portion of contact l6 adjacent to projections 8 which form the contact surface for the stationary switch contact. As switch 29 is closed, in additionto the above-described action of the projection 33 sepa rating the parts of contact I6, it is also forced upwardly due to the vertical component of movement of the switch 29 in its rotation about lower switch contact 26. This produces a spring tension tending to force fuse holder 3| downwardly. Also, the separating of the two parts of upper switch contact l6 by the conical projection 33 produces a force tending to move the fuse holder 3| downwardly. However, as long as fuse link 3| is intact, fuse holder 3| cannot move downwardly and rotational movement of fuse holder 3| is prevented by the abutting surfaces of contact l6 adjacent to the contact surface within which projection 33 is seated.

Upon operation of the fuse link, the support for toggle 34 is removed and so it rotates about the pivot formed by switch contact 26. Due to the eccentric pivotal connection between toggle 34 and fuse holder support 35, the movement of toggle 34 is not retarded by its connection to the support 35 and acts to vertically lower the fuse holder 3i as the toggle 34 swings open. Due to the conical projection 33 on contact cap 32 extending between the contact cap and the switch l6 it prevents rotation of the fuse holder. The reaction to' the expulsion of the high-pressure gases from the bottom of the fuse holder tube 3| prevents it dropping out immediately upon the operation of the fuse and following the action of toggle 34. Also, the projection 33 prolongs the time that the contact cap 32 is in engagement with switch contact l6 during vertical movement of fuse holder 3|. This time delay upon the automatic operation of the switch 29 is important as it permits the are drawn on the operation of the fuse link to be completely extinguished within the fuse holder-3| before the switch opening begins. Thus the arc is extinguished entirely within the fuse holder 3|. If this time delay were not provided then a secondary arc would be drawn upon the separation of contact cap 32 from engagement'with switch contact it. This are would be more difficult to extinguish than the one located wholly within the fuse holder ti and resu t in erious damage to the fuse holder and is in. Fig. l the position of fuse holder s indicated shortly after the operation of the fuse link with the fuse holder 3i having moved longitudinally until the contact cap has separated from the switch contact l6. Longitudinal movement of fuse holder El is assisted by the pressure exerted by the two parts of contact 06 on conical projection which is of par- .ticular importance when sleet or ice has formed on the switch contact iii. Fuse holder 3! then follows the movement of toggle 34 opening the switch 29 and assuming an angular position with the support 35 in engagement with projection 38 of toggle 34. Eoggle 34 is stopped in its rotation about the pivot formed by switch contact 26 by engagement between projecting pins 39 of toggle 34 and side plates 49 secured to switch contact 26. The arrangement of the toggle 34 and fuse holder support 35 is not my invention, but it is the subject of a copending application Serial No. 692,448 filed concurrently herewith in the names of C. J. B. Olsen and G. F. Lincks and assigned to the same assignee to which this application is assigned.

For manual operation of the switch 29 and for removal of the fuse holder 3| to replace the fuse link located therein, a switch handle 4| is provided. Switch handle 4| is secured to fuse holder 3i adjacent the contact cap 32, the switch handle 4| being held in position on the fuse holder 3| by means of a screw 42. To prevent radio interference by static discharge between the metal switch handle 4| and contact cap 32, a small copper wire spring 43 is provided engaging the switch handle 4| and contacting with the cap 32. An opening 44 is provided extending transversely of the switch handle through which the hook 45 of a switch stick 46 is adapted to pass. Switch stick 46 is of the usual type used for opening and closing disconnecting switches and in Fig. 2 it is indicated in position for closing the switch 29. By pulling on the switch stick 46 the switch 29 would be opened. In Fig. 5 a detailed perspective View of switch handle 4| shows a strap 41 which extends between the two parts of the switch handle adjacent the upper part of opening 44. Strap 4'! is provided for engagement with the hook 45 of switch stick 46 in the manner indicated in Fig. 3 for the removal of the fuse holder 3i when it is desired to replace the fuse link 3|. lit will be seen in Fig. 5 that the two parts of switch handle 4| are so formed as to fit the top of switch stick 46 snugly so that the fuse holder 3| is securely held by switch stick 46 and may be easily removed from the switch contact 26 without the danger of the fuse holder 3| falling to the ground after it has been lifted from the contact 26.

From the foregoing it may be seen that the I projection 33 retards the opening of the switch to permit the extinction of the are within the fuse holder 29 before the switch begins its opening operation. In addition, the shape of projectlon 33 insures the opening of the switch upon the operation of the fuse regardless of whether or not the switch contacts are covered with sleet or ice. The switch handle 4i provides a means for the opening and closing of the switch 29 and the removal of the fuse holder 3i to replace the fuse link and make it possible for the linemen to perform these operations even at a distance of fifteen feet or more from the switch depending upon the length of the switch stick 46 at a rela from any live parts of the the switch handle 4| makes apparatus "ig these operations as all that is necessary.

or equipment ior no he usual switch sti ating handle and said contact cap to prevent static discharge therebetween.

2. An electric switch comprising stationary switch contacts, a fuse link, a fuse holder tube, a contact cap closing one end of the fuse holder tube and having a projection adapted to engage one of said switch contacts, means to removably support and pivot the fuse holder on another of said switch contacts, an operating handle secured to the fuse holder and spaced from the contact cap, and spring means to connect the operating handle to the contact cap.

3. An electric switch including in combination, supporting means, stationary switch contacts carried thereby, a fuse holder, means for removably and pivotally mounting said fuse holder on said supporting means for connection between said stationary contacts, and an operating handle secured to the fuse holder and constructed to provide for both manual operation of the switch and removal of the fuse holder from the supporting means by means of a switch stick having a hook member adjacent the end thereof and projecting substantially at right angles to the stick, said handle having socket means arranged to receive said hook member with the hook member disposed transversely of the longitudinal axis of the fuse holder and other socket means arranged to firmly engage the end of the switch stick and the hook member with the hook member disposed substantially parallel to the longitudinal axis of the fuse holder.

4. An electric switch comprising supporting means, stationary switch contacts carried thereby, a fuse holder, means for removably and pivotally mounting the fuse holder on said support' ing meansfor connection between said stationary contacts, and an operating handle secured to the fus holder and having two parts disposed in spaced relation and provided with aligned openings for the reception of a hook member projecting from the end of an operating switch stick, said handle having also a strap member extending between said two parts and arranged to be engaged by said hook member when the end of said switch stick is inserted between said two parts.

5. An electric switch comprising stationary switch-contacts, a fuse holder, means to removably support and pivot the fuse holder on one of said switch contacts, and an operating handle secured to the fuse holder and having two parts with a transverse opening passing through the two parts, and a strap adjacent the opening connecting the two parts adapted for manual operation by a switch stick having a hook passing through the transverse opening and removed by a hook engaging the ponnecting strap.

6. An electric switch comprising a switch contact having adjacent portions of a rod forming a contact surface, a second switch contact, a fuse holder, a contact secured to the fuse holder and having a conical projection adapted to pass between the two parts of said switch contact, means to support and pivot said fuse holder on said second switch contact, and means to release said fuse holder upon operation of the fuse whereby rotary movement of the fuse holder is opposed but longitudinal movement is permitted.

'7. An electric switch comprising supporting means, a stationary switch contact mounted on said supporting means and having abutting surfaces resiliently biased toward each other, a second stationary switch contact, a fuse holder, a contact secured to said fuse holder and having a conical projection arranged to be engaged by the abutting surfaces of said first-mentioned stationary switch con-tact upon closing of the switch, means for supporting said fuse holder pivotally on said supporting means for connection between said stationary contacts, a fuse link located in said fuse holder, and means for releasing the support of said fuse holder upon the operation of the fuse link.

8. An electric switch comprising a stationary switch contact having abutting surfaces resiliently biased toward each other, a second switch contact, a fuse holder, a fuse link located in said fuse holder, means to pivotally support said fuse holder on said second switch contact, a contact secured to said fuse holder and having a conical projection passing between the abutting surfaces of said first-mentioned switch contact.

whereby rotary movement of the fuse holder is resisted but the pressures of said surfaces on said conical projection tends to effect longitudinal movement of the fuse holder.

9. In a disconnect switch, the combination with an insulating support and a movable connecting member pivotally mounted on said support, said member having a contact finger projecting axially from and tapered outwardly relative to the end of said member, of a contact comprising a pair of spaced resilient arms receiving said finger between them in frictional engagement therewith.

10. In a disconnect switch, the combination with an insulating support and a movable con necting member pivotally mounted on said support, said member having a contact finger projecting axially from 'and tapered outwardly relv ative to the end of said member, of a contact comprising a pair of spaced resilient arms receiving said finger between them in frictional engagement therewith, and latching means on said arms holding said finger against lateral movement but permitting endwise movement of said pin.

11. In a disconnect switch, the combination with an insulating support and a movable connecting member pivotally mounted on said support, said member having a contact finger projecting axially from and tapered outwardly relative to the end of said member, of a contact comprising a pair of spaced resilient arms receiving said finger between them in frictional engagement therewith, at least one of said arms having a portion converging toward the other for latching said member in frictional engagement with said arms.

12. In a disconnecting switch, the combination with an insulating support and a movable conprising a pair of spaced resilient arms receiving said finger between them and in frictional engagement therewith, at least one of said arms wiie oi-oiigs resiiieistiy itoovab' having a portion converging toward the other for latching said leer iii triotioiiai engage= meat with said aims.

in a disconnect switch, the combination of an pivotaily mounted at one encl on said. support, a contact oaixied. by the support and comprising a pair of spans-cl substantially parallel resilient movable in a direction relatively towards the pivotal mounting of said tubular fuse cartridge, and a term E1 cap closing the other end of said tubular i .s-e cartridge and having a tapered contact pin integral therewith and projeoting therefrom to be received between said saicl arms being in friotioiial engagement with the sides of said pin.

a disconn ct switch including a support, the combination with a fuse tuioe opeo one enol and closed at the other end by a having a tapered pin integrally thereiirith projecting concentrically relative to the tube, of a pivot carried by the support and upon which time open end of the tuloe is mounted, and a oontaet e rietl by supoort and oo' 'orising a toward pivot extending substantially relat vely s prongs having COiiVGlg'iiig L about said ll iai en sides thereof to latch e ise closing position wrongs be). to exert pressure on cap towaz'tlisaicl -5. I a cutout switch, pivotaii; 61L tube 011-" one and closed at the otl of a metal cap hav ng a te eretl extending centrally with a terminal contact ooi' resilient 21 meets f said es tossing and gt ovemen opeio. circuit oclily ieia meat of the L1 fuse tube is movaole o

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