US3198918A - Bracing and support structure for oil circuit breakers - Google Patents

Description

Aug. 3, 1965 Filed Feb. 13, 1961 J. R. MCCLOUD BRACING AND SUPPORT STRUCTURE` FOR OIL CIRCUIT BREAKERS 5 Sheets-Sheet 1 INVENTOR. .L4/Wifi. /WZYV Aug. 3, 1965 BRACING AND SUPPORT STRUCTURE FOR OIL CIRCUIT BREAKERS Filed Feb. 15, 1961 J. R. MocLouD 3,198,918

5 Sheets-Sheet 2 Aug- 3, 1965 J. R. MccLoUD 3,198,918

BRACING AND SUPPORT STRUCTURE FOR OIL CIRCUIT BREAKERS Filed Feb. 13. 1961 5 SheebS-Shee(l 5 United States Patent O 3,193,913 BRACING AND SUPIRT STRUCTURE FR GIL CIRCUIT BREAKERS .lames R. McCloud, Los Angeles, Calif., assigner to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Feb. 13, 1961, Ser. No. 83,829 3 Claims. (Cl. Z110-150) My invention relates to a novel brace and support structure for oil circuit breakers of the type set forth is my copending application Serial No. 67,125, tiled November 3, 196), now abandoned, entitled, Three Phase Oil Circuit Breaker, and assigned to the assignee of the present invention, and more specifically relates to a bracing arrangement which braces the lower bushing structures and the lift rod guides to prevent dama-ge to the bushing and to prevent misalignment between the interrupter and the movable contacts during fault conditions.

In yinterrupters of the type to which the invention applies, bayonet type contacts carried by an insulating lift rod are moved into and out of engagement with an elongated inteirupter which is immersed in oil and contains the stationary contacts which cooperate with the movable bayonet type contacts. These interrupters are carried at the lower end of bushings which enter the upper housing portion of the circuit breaker. During cir-cuit breaker operation, as the movable contact leaves .the interrupter, a jet of oil and gas is expelled through the exhaust ports of the interrupters and the reaction force of these jets is such as -to place a cantilever force on the lower bushing supports which carry the interrupters. If there is insutiicient bracing, the interrupter and movable contact moving out of the interrupter will be misaligned before the movable contacts clear the interrupter so that there can be a permanent distortion of the contact which, in some cases, can cause a severe enough deflection of the lower bushing as to damage it. Moreover, and even where the contact leaves its interrupter without causing damage, there may be a permanent misalignment created so that the movable contact cannot successfully enter `its interrupter when the circuit breaker is closed.

In the past, braces have been provided for the lower portion of the bushing which receive the interrupter attachment where the braces are connected to the bushing adapter by means of a friction joint held in place with nuts and bolts. With this design, however, when sui'licient reaction force is applied to the interruptor, the braces have slipped at their friction connection to permit distortion of the bushing, The principle of the present invention is to provide a novel positive brace connection between the braces and bushing adapters whereby the Various interrupters throughout the circuit breaker are rigidly contained in predetermined posi-tions with respect to one another and there can be no slipping at the brace connection to the bushing.

In combination with this, the bushings are secured to the circuit breaker tank to permit adjustment of their angular position during assembly so that minor dimensional misalignments can be absorbed when the bushings are accurately located in their positions determined by the positive brace structure.

Moreover, I use the bracing structure as a guide for the main lift rod to thereby effect a considerable saving in cost and in the number of components required in the system.

Accordingly, a primary object of this yinvention is to provide a bracing arrangement for bushings of oil circuit breakers which cannot slip.

Another object of this invention is to provide a positive brace structure between the lower bushing portions of the bushings of the oil circuit breaker which rigidly locate the position of the bushings with respect to one another.

A further Object of this invention is to provide a novel bushing mounting construction which permits the use of a positive brace construction for the lower end of the bushings.

A further object of this invention is to provide .a nonslip brace arrangement for the lower bushing portions in oil circuit breakers which further may be used 4in guiding the lift rod of the circuit breaker.

These and other objects of this invention will be apparent from the following description when taken in connection with the drawings in which:

FIGURE l shows a cross sectional View of a threephase oil circuit breaker arrangement which is adapted with the bracing structure of the present invention.

FIGURE 2 is a schematic cross sectional view of the circuit breaker of FIGURE l and its operating mechanism.

FIGURE 3 is a side cross sectional view taken through the novel positive brace structure of the present invention for one of the phases of FIGURE l.

FIGURE 4 is a side plan View of the bracing arrangement of FIGURE 3.

FIGURE 5 is a cross sectional view through the bushing support for one of the bushings which has the positive brace structure of the invention connected thereto as shown in FIGURES l, 3 and 4.

FIGURE 6 illustrates the manner in which one of the moving contacts is secured to its cross bar.

FIGURE 7 is a `top plan view of FIGURE 6,

FIGURE 8 is a side plan view of FIGURE 6.

Referring first to FIGURES l and 2, I have shown therein a three-phase oil circuit breaker of the type set forth in my copending application Serial No. 67,125. For various constructional details of this three-phase circuit breaker, reference is made to copend-ing application Serial No. 67,125 which is incorporated as a part of the instant application. Generally, as shown in FIGURES 1 and 2, the three-phase circuit breaker includes two interrupters in series for each phase. Thus, a rst phase is formed of bushings 10 and 11 .which are mounted to a top frame 12 in a manner to be described more fully hereinafter, where bushings 10 and 11 carry interrupters `13 and 14 respectively at their inner ends, The manner in which . interrupters 13 and 14 are constructed and connected to bushings 10 and 11 is .set forth in detail in the above noted applicat-ion Serial No. 67,125, as well as in copending application Serial No. 2,530 (now abandoned) iiled January 4, 1960, in the name of Earl B. Rietz, entitled, Single Contact Interrupters, and assigned to the assignee of the present invention.

As is completely described in either of the above applications and as is well known to those skilled in the art, the interruptors 13 and 13 will carry stationary contacts therein which receive bayonet type contacts 15 and 16 which are connected to a common conductive cross bar (not shown) whereby contacts 15 and 16 are connected in series. The interrupters 13 and 14 are further immersed in oil which is contained within the main tank portion 17 which has top frame 12 as its cover and is connected thereto through an annular gasket means contained in top frame 12.

The second and central phase of the interrupter includes bushings 18 and 19 which again are secured to top frame 12 in a manner to be described hereinafter and are terminated by interrupters 20 and 21 which are identical to interrupters 13 and 14. The interrupters 20 and 21 cooperate with movable bayonet type contacts 22 and 23 respectively which are carried by a conductive cross bar 24 which electrically connects contacts 22 and 23 in series.

sacaste The third phase, not shown in FIGURE 1, is schematically illustrated in FIGURE 2 as including bushings u and 25b which are similar to bushings 10 and 11 whereby the ends of bushings 25a and 25h carry interrupters 26 and Z7 respectively which cooperated with contacts which are connected in series through a common conductive cross bar. 4

The manner in which the bayonet type contacts, such as contact 22, are secured to their cross bars, such as cross bar 24, is illustrated in FGURES 6 and 7 and 8 where it yis seen that the cross bar 24 is composed of parallel conductive bars 24a and 24h, which could be of aluminum or other material and are terminated at either end by a conductive block 2S which has a slot 2% therein and a threaded opening 30. If desired7 and as shown in FIGURE 6, the conductive block 28 and cross bars 2da and 24h may have centrally located notches which receive keys 30 and 31 for accurately locating and securing the block to the cross bars. The block 28 is further secured to the cross bars by bolts 32 and 33 which pass through cooperating openings in cross bars 2da and Z411 and appropriately positioned slots in block 24 as illustrated in FIGURE 8.

The bayonet type contact 22 of FIGURE 6 has a threaded lower portion 34 which is threaded into tapped opening 36 of block 28. Thereafter, bolts 32 and 33 are tightened where the tightening of bolt 33 causes compression of slot 29 and forms a rigid electrical and mechanical engagement between tapped opening 30 and bayonet contact 22. In order to adjust the height or" the bayonet contact 22 it is apparent that it is only necessary to thread bayonet contact 22 within tapped section 39 before securing bolts 32 and 33.

Each of the cross bars for the bayonet contacts of each or the phases of the circuit breaker or FIGURES 1 and 2 are then secured to respective lift rods which could be of wood, such as the lift rods 60, 61 an'd 62 for the upper middle and lower phase respectively of FIGURE 1.

Lift rod 61 is shown in side view in FIGURE 1. The lift rods 60, 61 and 62 extend through guide structures to be described more fully hereinafter and terminate on an operating mechanism output means 63 (FIGURE 1) of the operating mechanism 64 schematically illustrated in FIGURE 2. Details of this operating mechanism may be had by reference to the above noted copending application Serial No. 67,125. It is sufficient for purposes of the present invention to understand that the operating mechanism will cause lift rods 60, 61 and 62 to move axially from the contact engaged position of FIGURE 1 to a disengaged position whereby lift rods 66, 61 and 62 are driven downwardly to cause the ends of their bayonet contacts to clear the bottom of their respective interrupters.

As previously indicated and as is Well known to those skilled in the art, the interrupters, such as interrupters 13, 14, 20 and 21 of FIGURE 1 have exhaust ports therein through which oil and gas are vented during interrupting conditions. The direction of this Iblase is schematically illustrated in FiGURE 2 by the arrows 65, 66, 67, 63, 69 and 7d of interrupters 13, 1d, 21, 27, 26 and 2t) respectively. The reaction force due to this jet type of action can be substantial and can cause serious deflections of the lower ends of the bushings such as bushings 1t), 11, 1S and 19. Such deflections can be sui'icient to either seriously damage the bushings or cause enough misalignment between the interrupters and their respective movable bayonet contacts as to cause permnent distortion of the bayonet contacts, destruction of the interrupters and prevention of re-engagement of the bayonet contacts and their respective interrupters after the circuit breaker is opened. For this reason, it is essential to provide bracing means which will prevent such deiiection.

In accordance with the present invention, a novel brac- Cil ing arrangement is provided whereby the bushings of each respective phase are positively braced to one another by a non-slip type of connection whereby the equal and opposite reaction forces on each of the interrupters of each phase are contained within this rigid brace to prevent movement of the interrupters under interrupting conditions. The bracing structure for each of the phases is shown in FGURES 1 3 and 4 as bracing structures 71 for bushings i3 and 19 which have interrupters 20 and Z1 terminated thereon. It will be apparent that the remaining two phases will have identical types of bracing structures whereby the ends of bushings 10 and 11 will be braced in exactly the manner to be described hereinafter for bushings 13 and 19, and in a like manner those bushings supporting interrupters 26 and 27 will have an identical positive braced arrangement. The brace arrangement generally identilied by numeral Z1 in FIG- URE 1 is more specically illustrated in FIGURES 3 and 4 as being comprised of a pair of parallel extending arms 72 and 73 of insulating material such as wood which has been appropriately treated in the usual manner.

The bushing 18 has a lower conducting stud 74 which has a thread tapped thereon for receiving a conductive bushing interrupter adapter 75 which has a cooperating thread and has an axially directed slot in one wall thereof whereby a bolt means, such as bolt 76, can rigidly clamp the adapter 75 on the threaded portion of stud 74. In a like manner, the end of bushing 19 has a conductive stud 77 which is electrically and mechanically secured to a bushing interrupter adapter 78. Each of bushing interrupter adapters 75 and 78 then have necked down conductive portions 79 and (it) and are secured to their 4respective interrupters 2t? and 21 in the usual manner. Details for the manner in which the bushing adapter may be secured to the appropriate interrupters are given in the above noted copending application Serial No. 2,530.

The necked down portions 79 and Sti of bushing interrupter adapters 75 and 78 receive split anchor clamps 31 and S2 which are composed of two halves such as halves 83 and 84 for the case of anchor clamp 81. The outer ends of the halves of anchor clamps 81 and 82, such as halves 83 and S4 of anchor clamp 81 contain inner shoulders 85 and 86 respectively which are the inner surfaces of anges 87 and S8. The inner shoulders 85 and S6 are circular and cooperate with the circular end shape which is given to each end of rods 72 and 73. The split anchor clamps S1 and 82 are then adapted with enlarged cylindrical cutout portions which receive necked down portions 79 and 8G respectively as shown and are clamped to these necked down portions as by provided bolt means, such as bolts S9 and 90, which extend through projecting ears 91 and 92 of the two halves 83 and 84 respectively as shown for split anchor clamp 81. The opposite ends of the anchor clamps are secured to rods 72 and 73 by a bolt means 93 which extends through aligned openings at either end of rods 72 and 73 and at registering slot 94 (FEGURE 4) in the split anchor clamp such as split anchor clamp 81. The end of bolt 93 is terminated by a nut 95 with appropriate washer means such as washers 96 and 97 being used in the nut and bolt arrangement.

With the novel construction set forth above, it will now be clear that the reaction forces applied by the interrupters during interrupting conditions will be inwardly directed to set up compression forces on rods 72 and 73. The rods, however, abut shoulders of the split anchor clamps such as shoulders S5 and 86 whereby there is a positive connection between the anchor clamps which are connected to the ends of the bushings and the rods 72 -and 73. These opposing forces caused, for example, by interrupters 20 and 21, will be equal to one another in opposite directions so that the full compressional forces will be taken up within rods 72 and 73 with no motion of the ends of bushings 18 and 19. Moreover, since a frictional clamp is not utilized, there is no possibility of slippage of the bracing arrangement.

The novel bracing structure of the invention further serves as a guide for the lift rod of its respective phase. Thus, in FIGURES 3 and 4 for the case of the central phase of the circuit breaker of FIGURE l, shoulder pins and 1M are secured to appropriate openings in registry with one another in rods 72 and 73. Shoulder pin 100 secures positioning Washers 102 and 103 in the position shown in FIGURE 3 while shoulder pin 101 secures positioning Washers 104 and 1115 in the position shown in FIGURE 3. Thus, shoulder pins 100 and 101 and Washers 102, 103, 104 and 165 define a guide aperture for lift rod 61 which is contained within the opening formed as shown in FIGURES 3 and 4. This guide, in connection with the upper connection of the lift rod to the output means 63 of the operating mechanism will serve to guide the motion of lift rod 61 so that the position of bayonet contacts 22 and 23 will be accurately located with respect to interrupters and 21.

As indicated heretofore, when the bracing structure of the invention is assembled it is possible that, due to the manufacture process, there will be inherent misalignment in the position of the lower ends of the bushings so that the positive bracing structure cannot be applied. Accordingly, in combination with the novel positive bracing structure, I -also provide a novel pivotal mounting arrangement for the individual bushings which Will permit their pivotal adjustment to conform with the positive prepositioning of the ends of the bushings caused by the novel positive bracing arrangement. A cross sectional view of the novel bushing support of the invention is shown in FIGURE 5 for the cast of bushing 18. Thus, in FIGURE 5, bushing 18 has a circular bolt iiange 110, while the top frame 12 has an annular steel ring 111 welded thereto about the periphery of opening 112 which receives bushing 18. An annular ring 113 is then placed on the bottom of bolt ring 110 and has openings spaced along the periphery thereof which register with the openings in bolt ring 110. The inner corner of annular ring 113 is rounded as illustrated by rounded portion 114 and bears against a tapered or conical surface 115 of ring 111. The ring 111 further has bolts, such as bolts 116 and 117, extending therefrom in registry with the positions of the openings in rings 113 and 110 whereby the ends of the bolts, such as bolts 116 and 117 which extend above the surface of bolt ring 110, can receive nuts such as nuts 118 and 119 respectively. It is to be noted that while in FIGURE 5 I only show two bolts 116 and 117, that at least three bolts should be provided and preferably a large number of bolt means will be used. An appropriate O-ring gasket 120 is then contained between the bottom of ring 11) and the top of ring 111.

With the arrangement described in FIGURE 5 it will now be seen that since rounded portion 114 of ring 113 sits on a tapered surface 115 that a certain amount of angular play is provided for the mounting of bushing 18. Therefore, it is possible during the mounting process to permit bushing 18 to assume its required angular position and thereafter to secure the nuts such as nuts 118 and 119 to rigidly retain the bushing 18 in this angular position.

It is now possible to describe the manner in which the bracing structure is applied to the system. The bushings are first placed on top frame 12 and are lightly secured thereto by bolting their bolt rings, such as bolt ring 110 to top frame 12. Thereafter, the split anchor clamps are applied to the necked down portions of the bushing adaptors which have been previously secured to their interrupters and bushings. The side bars such as side bars 72 and 73 are then assembled with the shoulder pins connected in place around their respective lift rods and the anchor clamp and are rigidly secured in place. During this operation it will be noted that since the ends of rods 72 and 73 engage the inner shoulders of the anchor clamps along a common radius that the bushings can be moved by pivotally rotating the bushings in their support with the dimensional changes between the rods and the anchor clamps being absorbed along this radius. Once the appropriate position which will thereafter be rigidly maintained between the bushings is achieved the bushings are rigidly clamped to the top structure.

In the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein, but only by the appending claims.

I claim:

1. In an oil circuit breaker, including a first and second elongated bushing supported from the top of said oil circuit breaker and extending into said oil circuit breaker, and a first and second interrupter secured to the ends of said first and second elongated bushings; said first and second interrupters having reaction forces generated thereon during circuit breaker operation having at least components toward one another; a bracing structure connected to end portions of said first and second elongated bushing adjacent said first and second respective interrupters; said bracing structure including an elongated insulated bracing member extending from said end portion of said first elongated bushing to said end portion of said second elongated bushing and a first and second positive clamp means; said first and second positive clamp means having respective first clamping portions rigidly connected to said end potrions of said first and second elongated bushings; said first and second positive clamp means having respective second clamping portions rigidly connected to respective end surfaces of said elongated insulating bracing member; said elongated bracing member being comprised of a first and second parallel spaced rod; the end surfaces of said first and second parallel spaced rods respectively extending beyond said first and second end portions of said first and second elongated bushings and on either side of said first and second end portions.

2. In an oil circuit breaker, including a first and second elognated bushing supported from the top of said oil circuit breaker and extending into said oil circuit breaker, and a first and second interrupter secured to the ends of said first and second elongated bushings; said first and second interrupters having reaction forces generated thereon during circuit breaker operation having at least components directed toward one another; a bracing structure connected to end portions of said first and second elongated bushings adjacent said first and second respective interrupters; said bracing structure including an elongated insulated bracing member extending from said end portion of said first elongated bushing to said end portion of said second elongated bushing and a first and second positive clamp means; said first and second positive clamp means having respective first clamping portions rigidly connected to said end portions of said first and second elongated bushings; said first and second positive clamp means having respective second clamping portions rigidly connected to respective ends of said elongated insulating bracing member; said elongated bracing member being comprised of a first and second parallel spaced rod; the end surfaces of said first and second parallel spaced rods respectively extending beyond said first and second end portions of said first and second elongated bushings and on either side of said first and second end portions; said second positive clamping portions including abutting portions directly abutting its said respective end surface of said elongated bracing member; said end surfaces of said elongated bracing member being curved on a radius; said abutting portions of said positive clamping portions being curved on said radius of said end surfaces of said elongated bracing member; said first positive clamping portions at least partially surrounding said respective end portions of said first and second elongated bushing.

3. In an oil circuit breaker, including a first and second d elongated bushing supported from the top of said oil circuit breaker and extending into said oil circuit breaker, and a first and second interrupter secured to the ends of said rst and second elongated bushings; said first and second interrupters having reaction forces generated thereon during circuit breaker operation having at least components directed toward one another; a bracing structure connected to end portions of said rst and second elongated bushings adjacent said rst and second respective interrupters; said bracing structure including an elongated insulated bracing member extending from said end portion of said first elongated bushing to said end portion of said second elongated bushing and a rst and second positive clamp means; said iirst and second positive clamp means having respective first clamping portions rigidly connected to said end portions of said rst and second elongated bushings; said first and second positive clamp means having respective second clamping portions rigidly connected to respective end surfaces of said elongated insulating bracing member; said elongated bracing member being comprised of a Iirst and second parallel spaced References Cited by the Examiner UNITED STATES PATENTS 1,801,114 4/31 Schwennker 200-150 1,805,497 5/31 Paul 200--150 2,014,634 9/35 Polgov 174-163 2,889,396 6/59 Boden et al 174-161 3,071,672 1/63 Mitchell 20G- 150 FORETGN PATENTS 230,289 1/59 Australia.

BERNARD A. GXLHEANY, Primary Examiner.

MAX L. LEVY, ROBERT K. SCHAEFER, Examiners.

Claims (1)

1. IN AN OIL CIRCUIT BREAKER, INCLUDING A FIRST AND SECOND ELONGATED BUSHING SUPPORTED FROM THE TOP OF SAID OIL CIRCUIT BREAKER AND EXTENDING INTO SAID OIL CIRCUIT BREAKER, AND A FIRST AND SECOND INTERRUPTER SECURED TO THE ENDS OF SAID FIRST AND SECOND ELONGATED BUSHINGS; SAID FIRST AND SECOND INTERRUPTERS HAVING REACTION FORCES GENERATED THEREON DURING CIRCUIT BREAKER OPERATION HAVING AT LEAST COMPONENTS TOWARD ONE ANOTHER; A BRACING STRUCTURE CONNECTED TO END PORTIONS OF SAID FIRST AND SECOND ELONGATED BUSHING ADJACENT SAID FIRST AND SECOND RESPECTIVE INTERRUPTERS; SAID BRACING STRUCTURE INCLUDING AN ELONGATED INSULATED BRACING MEMBER EXTENDING FROM SAID END PORTION OF SAID FIRST ELONGATED BUSHING TO SAID END PORTION OF SAID SECOND ELONGATED BUSHING AND A FIRST AND SECOND POSITIVE CLAMP MEANS; SAID FIRST AND SECOND POSITIVE CLAMP MEANS HAVING RESPECTIVE FIRST CLAMPING PORTIONS RIGIDLY CONNECTED TO SAID END PORTIONS OF SAID FIRST AND SECOND ELONGATED BUSHINGS; SAID FIRST AND SECOND POSITIVE CLAMP MEANS HAVING RESPECTIVE SECOND CLAMPING PORTIONS RIGIDLY CONNECTED TO RESPECTIVE END SURFACES OF SAID ELONGATED INSULATING BRACING MEMBER; SAID ELONGATED BRACING MEMBER BEING COMPRISED OF A FIRST AND SECOND PARALLEL SPACED ROD; THE END SURFACES OF SAID FIRST AND SECOND PARALLEL SPACED RODS RESPECTIVELY EXTENDING BEYOND SAID FIRST AND SECOND END PORTIONS OF SAID FIRST AND SECOND ELONGATED BUSHINGS AND ON EITHER SIDE OF SAID FIRST AND SECOND END PORTIONS.

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