US2106616A - Switch and bus insulator stack - Google Patents

Description

Jan. 25, 1938. R. L. M COY SWITCH AND BUS INSULATOR STACK Filed Nov. 6, 1935 2 Sheets-Sheet l 35 6 790%? .43. fifg Jan. 25, 1938. R. L. MccoY SWITCH AND BUS INSULATOR STACK Filed Nov. 6, 1935 2 Sheets-Sheet 2 Patented Jan. 25, 1938 PATENT OFFICE 5106.618 swrrca AND nus msum'roa s'racx W L. New, Baltimore. 1111.,

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Locke Insulator Corporation, a corporation of Maryland Application am 0. ms, semiv No. 48,580"

6 m (Cl. 1318-418) The invention relates to an insulator assembly adapted for supporting a disconnecting switch mechanism, a bus or the like and has for its general object the provision of a novel insulating and supporting structure embodying the combination of certain insulators imder compression and certain others under tension, which may be mounted either in a vertical or a horizontal position and which is peculiarly and adequately braced against cantilever strains or in fact any distortion even under the most severe conditions of use.

It is well known that at the higher voltages, 220 kilovolts and upwardly, tall insulator stacks are required for supporting a switch mechanism, a bus, or other device. It has been found difllcult to build a completely self-supporting single post rigid enough to withstand the stresses involved without considerable deflection which causes diillculty for instance in satisfactorily maintaining proper alinement of disconnecting switch contacts. Due to the inherent flexibility of single post stacks, they present a considerable hazard under earthquake conditions which frequently ocour in the western and intermountain territory of this country. The flexibility of such stacks permits the insulators to get into a periodic vibratory condition if earth tremors continue for any appreciable periodof time and may result in the destruction of buses and switches.

It has been proposed to make use of tripod insulator stacks but these have proven diilicult to handle for several reasons. In disconnecting switches it is generally desired that one of the stacks of the tripod be capable of rotation for the transmission of mechanical energy for the operation of the switch contacts. Furthermore it is difficult to build the end fittings suiliciently accurately that when the stacks are bolted up they will fit together so neatly that no initial strains are set up in the stacks. Even where these precautions have been taken the tripod scheme is not particularly strong in torsion. Moreover when use is made of a tripod arrangement involving three stacks of pedestal or similar insulators, which are relatively expensive compared with other types, the cost becomes excessive.

It is with the above facts in view that I have devised the present invention which has for an important object the provision of a structure including a single stack of pedestal or other more or less similar insulators adapted to be placed and maintained under compression and braced by sets of other insulators under tension, the stack being rotatable in case the structure is used for supporting a disconnecting switch but being staprovide a structure of this character in which the insulator unit under compression is mounted at its lower end for limited rocking movement and in which the insulators under tension employed for bracing purposes are likewise pivotally connected, through the interposition of suitable flttings, with the top of the insulator under compression and to the main support upon which the entire structure is mounted, these features insuring that the tension in the sets of bracing insulators will equalize and throw no initial cantilever strains on the unit under compression, the latter being at all times held rigidly so that deflection will not occur even under the most adverse conditions, such for instance as in the event of earth tremors.

A further object of the invention is to provide an insulator assembly of this character equipped with means at the top and bottom for adequate protection against flash-over, this feature requiring but simple fittings which may be readily applied.

An additional object is to provide a structure of this characterwhich on account of being constructed of standard insulators which are in regular quantity production will be simple and inexpensive to construct as well as possessing the above mentioned advantageous characteristics which render it a distinct improvement in the art.

To the attainment of the foregoing and other objects and advantages, the invention preferably consists in the details of construction and the arrangement and combination of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawings in which:

Figure l is a side elevation of a switch supporting insulator assembly constructed in accordance with the invention and illustrating it as mounted in a vertical position,

Figure 2 is a plan view of the top yoke,

Figure 3 is a cross section on the line 3-3 01' Figure 2,

Figure 4 is a detail vertical section through the bottom support or bearing for the compression receiving unit,

Figure 5 is a fragmentary elevation showing more clearly the mounting of the lower end of one of the sets of bracing insulators under ten- Figure 6 is a side elevation of the structure showing it mounted in a horizontal position.

Referring more particularly to the drawings 55 the numeral 10 designates the supporting base which may be of structural steel or other construction and upon which the entire device is mounted. Suitably secured upon this base is a support ll having its top formed with a socket l2 and also formed with a central opening l3. Rockably mounted upon the support I I is a bearing member H having a depending portion engaged within the socket l2. This bearing member H has a central opening l6 through which and through the opening l3 extends a shaft I! provided at its upper end with a disk or adapter l8 suitably secured to the bottom of the lowermost one of a series of superposed insulators l9 here shown, for purposes of illustration, as of the pedestal type though certain others could be employed. Interposed between the bearing 14 and the adapter I8 is a thrust bearing here represented as of the ball type though there is no particular limitation in this respect. Secured to the top of the uppermost insulator I9 is an adapter 2| on the lower end of a shaft 22 adapted for connection with any ordinary or preferred type of switch contacts, not shown as being well known in the art. The shaft 22 passes through a hole 23 in the hub portion 24 of a spider-like triangular yoke 25 which has radial arms 26 formed at their ends with holes 21. Interposed between the adapter 2| and the hub portion 24 of the yoke is a thrust bearing 28.

For bracing the stack of pedestal insulators 19, I provide a plurality of sets of insulators under tension arranged about the stack and here shown, simply for purposes of illustration, as strings of suspension insulators 29 of any ordinary or preferred type but which are here disclosed as of the variety equipped with ball and socket means for connecting them in series. At the upper end of each string there isprovided a fitting 3D and these fittings are pivotally connected at 3! with the ends of the arms of the triangular yoke, the holes 21 receiving the necessary pivot bolts. At the lower end of each string is a fitting or bracket 32 and these are pivotally connected at 33 with eye bolts 34 extending through the base l0. These eye bolts are equipped with nuts 35 and interposed between the nuts and the base H) are coil springs 36 which provide means whereby the strings of suspension insulators can be placed under the desired predetermined tension so that the pedestal stack will be maintained rigid.

For protecting the entire structure against flash-over, I provide a grading ring 31 carried by a plurality of curved arms 38 suitably secured to the arms 26 of the triangular yoke at the top of the pedestal stack. This ring 31 cooperates with a plurality of substantially half rings 35 which are secured to the fittings or brackets 32 at the lower ends of the strings and which proiect outwardly away from the same and in an upwardly curved direction.

The entire assembly may be mounted in a vertical position as shownin Figure 1 in which event it is preferable that all of the suspension insulators be arranged with their convex sides up. However, if it is so desired, the assembly may be mounted upon a suitable support so as to extend horizontally in which event the uppermost string of suspension insulators would probably be reversed as shown in Figure 6. The structure is primarily intended as the support for a switch embodying appropriate contacts adapted to be operated by the shaft 22 when the shaft H is rotated by any suitable means, not shown. Upon removal of the thrust bearings 20 and 28 the device is well adapted for use for supporting a bus.

Reverting to the springs 36, it will be seen that it is a simple matter to determine definitely the amount of tension initially put on the suspension insulator strings as these springs can be so designed and calibrated that the coils will close tightly together at an accurately deter? mined value. Thus, in assembling, the constructor can draw the nuts 35 on the eye bolts 34 down until the coils of the springs are closed and this will indicate definitely the amount of force which has been applied. As the stack of pedestal insulators is rockably mounted at its lower end it can accommodate itself to the tension on the respective stringsso that the forces will be equalized. All cantilever stress is removed from the pedestal insulator stack which therefore operates only in direct compression. A distinct advantage of the entire assembly is that it consists of standard types of insulators which are produced regularly in quantities and there is consequently no necessity for the construction of any special units.

From the foregoing description and a study of the drawings it will be apparent that I have thus provided an assembly which is highly efficient for the purpose intended and which will be not only easy to assemble but also inexpensive. It is thought from the above that the construction, operation and advantages will be readily apparent to one skilled in the art without further explanation.

While I have shown and described the preferred embodiment of the invention, it should be understood that the disclosure is merely an exemplification of the principles' involved as the right is reserved to make all such changes in the details of construction as will widen the field of utility and increase the adaptability of the device provided such changes constitute no departure from the spirit of the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. An insulator assembly comprising a base, a socketed bearing member mounted on said base, a stack of pedestal insulators rockably mounted on said bearing member, shafts connected, respectively, with the top and bottom of the stack, said shafts being designed and adapted for the operation of switch means, a yoke at the upper end of the stack and through which the upper shaft extends, said yoke having a plurality of arms, a plurality of strings of suspension insulators arranged in a circumferential series about the stack, fittings at the upper ends of said strings pivotally connected with the yoke arms, eye bolts extending through the base, and fittings at the lower ends of the strings pivotally connected with said eye bolts.

2. An insulator assembly comprising a. base, a socketed bearing member mounted on said base, a stack of pedestal insulators rockably mounted on said bearing member, shafts connected, respectively, with the top and bottom of the stack, said shafts being designed and adapted for the operation of switch means, a yoke at the upper end of the stack and through which the upper shaft extends, said yoke having a plurality of arms, a plurality of strings of suspension insulators arranged in a circumferential series about the stack, fittings at the upper ends of said strings pivotally connected with the yoke arms, eye bolts extending through the base, fittings at the lower ends of the strings pivotally connected with said eye bolts, and spring means associated with said eye bolts for applying a predetermined tension upon said strings.

3. An insulator assembly comprising a base, a socket member mounted on said base, a bearing member rocka'bly mounted on said socket mentber, a stack of pedestal insulators, a thrust bearing interposed between said bearing member andthe adjacent end of the stack, a shaft rotatable through said socket and bearing member. and connected with the end or the stack, a second shaft secured to the other end of the stack, a yoke through which said second named shaft extends, a thrust bearing interposed between said yoke and the second named end of the stmk, a plurality of strings of suspension insulators ar ranged in circumferential series about the stack and pivotally connected with the yoke and with the base, and means for applying predetermined initial tension upon the strings.

4. An insulator assembly comprising a base, a socketed bearing member mounted on the base, an insulator rockably mounted on said heating member, shafts connected respectively with the top and bottom of the insulator, said shafts being designed and. adapted for the operation of switch means, a yoke at the upper end of the insulator and through which the upper shaft ex tends, said yoke having a plurality of arms, a plurality of insulator members arranged in a cir cumferentiaiseries about the insulator, fittings at the upper ends oi said insulator members piv otally connected with the yoke arms and fittings at the lower ends of said insulator members pivotally connected to said base, said insulator mombers extending at acute angle to the insulator and serving to hold it under compression and from sldewise movement on its support.

5. An insulator assembly comprising a base, a socketed member mounted on the base. an insulator rockably mounted on said bearing member, shafts (onnccted with the top and bottom of said insulator, said shafts being designed and adapted for the operation of switch means, a yoke at the upper end of the insulator and through which the upper shaft extends, said yoke having a plurality of arms, a plurality of insulator members arranged in a circumferential series about said insulator, fittings at the upper ends of said insulator members pivotally connected with the yoke arms, spring means for connecting the lower ends of said insulator members to the base for applying a predetermined tension on said insulater members, said insulator members errtending at an acute angle to said insulator whereby they serve to hold said insulator under compression and from sidewise movement on its support" 6. An insulator assembly comprising a base, a rocketed bearing member mounted on the here, an insulator rockably mounted on. said bearing member, a yoke carried by the upper insulator having a plurality of circumierenti spaced radially extending arms, a pinrahty ct rsulator members arranged in a oircumferen M series about the insulator, fittings at the un t ends of said insulator members pivotaliy n nected with the yoke arms and fittings at lower ends of said insulator members pivoteiiy connected to said base, said insulator members extending at an acute angle to the insulator and having their points of connection to the base far ther from the axis of the insulator than the points of connection to the arms, whereby they serve to hold said insulator under compression and. from sidewise movement on its support ROBERT L a

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