US1764419A - Insulator - Google Patents

Description

June 17, 1930f W. H. SCH RAMM INSULATOR Filed April 2, 1927 WITNESSES:

I lNV ENTOR (dd/fer .frfiramm Patented June 17, 193.0

WALTER H. SCI-IRAMM, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC 6'5 MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

INSULATOR Application fled April 2, 1927. Serial No. 180,448.

My invention relates to insulators of the high-voltage type and particularly to heavyduty insulators for supporting bus-bars or other conductors that exert cantllever load forces thereon.

One object of my inventlon is to provide an insulator of the above indicated character that shall be reinforced against cantilever load forces. Another object of my invention is to provide an insulator that shall so convert the cantilever load forces of one of its members into compression .forces in another member thereof as to more effectively utilize all of its component parts.

Another object of my invention is to provide an insulator that shall permit the use ofsa combustible insulating material for one of its main insulating elements and that shall be flame proof.

Another object of my invention is to provide an insulator, of a type in which porcelain'has heretofore been considered an essential material for one of its main elements, which may utilize other material than porcelain.

Another object of my invention is to provide an insulator that shall have high mechanical strength, that shall prevent relative slippage of its parts and that shall be free. from air between parts connected by a poured material.

Another object of my invention is to pro vide an insulator of the pillar or post type in which the top terminal is of such size, relative to the base thereof, and the other parts are so constructed and 'arranged, as to permit mounting the insulator to better advantage.

A further object ofmy invention is to provide an insulator that shall be simpleand durable in construction, economical to manufacture and effective in its operations.

Heretofore, in insulators of the pillar or post type, such as thoseemployed to support bus-bars and the like, it has been usual to provide porcelain cylinders or columns which are directly subject to cantilever load forces. In other words, there hasusually been but one main insulatin element to resist the main cantilever loa force.

This feature necessarily results in requiring the main load element to be heavy and the insulator large in comparison with the insulator of my invention, as will hereinafter appear.

The top and base terminal members of the prior insulators have also been of such size and character as to require undue mounting space, as well as to reduce the overall eiii ciency of the insulator in consideration of the voltages andmaterials employed.

Other objections to features of construction and operation have been present in the formerly employed insulators, as indicated in the above mentioned objects of my invlention.

It is my aim to provide an insulator, of the type indicated, that shall be free from the above-noted objections, in that the cantilever load forces shall be converted into load forces are so converted into compression forces, an outer terminal member is so reduced in size and mounted in a central non-refractory column, an outer refractory or other insulating shell is so shaped and related to the terminal members, and in which other features are so embodied as to overcome all of the objections mentioned and to attain all of the objects sought.

The single figure of the accompanying drawing is a longitudinal side view, partially in section and partially in elevation, of an insulator constructed in accordance with my invention.

The device comprises, in general, a base terminal member 2, a central longitudinally extending insulating column 3, an outer insulating shell or cylinder 4: surrounding the column 3, a sleeve 6 of yieldable insulating .material between the column 3 and the cylinder 4, and an outer end terminal member 7 The base member 2, preferably of metal comprises a laterally-extending discoi-dal substantially cup shape having corrugated or roughened longitudinal sides for anchoring the member 2 in the column 3.

he outer end terminal member 7 also 1 preferably of metal, comprises a laterally extending discoidal portion 16 havin an annular rib 17 between the column 3 an the cylinder 4 for centerin the parts and a tapped opening 19 for t e threaded end 20 :of a central longitudinal portion 21 projecting into the column 3 toward the portion 14 of the base member 2. Theportion 21 is preferably permanently secured to the discoidal, portion 16, as by upsetting the .threads at its outer end. The portion 21 may also be provided with a corrugated longitudinal surface and an enlarged lnner end 23. for anchoring the terminal member 7 to the column 3 to prevent slippage of the parts. A 'yieldable gasket 22, of cork' or other suitable material, is disposed between the shell 4 and the portion- 16 and extends to a position around the rib '17.

.The column 3 is preferably of non-refractory hard molded material, such as hard rubber or a compound, and is molded tofrusto-conical shape about, and between, the projections 14 and 21, with 1ts ma or or larger base about the base pro'ection 14.

The shell or cylinder 4, pre rably of porcelain or glass, although other suitable material may be employed, is of tubular frusto-conical construction having an inner surface closely conforming to, and slightly .5 aced from, the frusto-conical surface of t e column 3 and an outer corrugated or creepagesurface 25. The major base of the shell 4 is preferably of. substantially the same diameteras the discoidal portion 9 and is provided-with perimetral recesses 27 for the reception of the heads 28 of the bolts 11.

' The lower outer perimeter 30 of the shell 4 is preferably rounded or otherwise formed to conform to, or cooperate with, the upturned edge portion 12. A asket 31 of yieldable material, such as cor is disposed between the portion 9 and the shell 4 and also extends to .a position between the upturned edge 12 of the part 9 and perimeter 30 of the shell 4.

' The sleeve 6 is preferably of relatively soft yieldable insulating material, such as a soft-rubber composition, which may be poured into position to drive out air and projecting central portion 14 of inverted.

lever or lateral forces in the inner column .3 into compresslon forces in the outer shell 4. In other words, the frusto-conical shell lateral or cantilever forces tending to bend the portion 16 downwardly or the column 3 laterally about a point on its longitudinal axis, place the shell 4 in compression. The

shell 4 might be of other shapes to accomplish this purpose ,but the frusto-conical shape shown utilizes the inherent strength substantially maximum adof the shell to vantage, permits the outer terminal parts to be smaller and provides space under the portion 16 for bolt heads of clamp parts which'might otherwise occup undue space and'reduce the flash-overrvo tage value of thainsulator.

In similar insulators heretofore employed the'cantilever load force has been place 4 acts as a prop under the portion 16 so that directly on a single refractory cylinder or column and the terminal members have projected toward each other an undue distance outside the insulator.

The upturned edge 12 cooperates with. the perimeter 30, through the asket 31, to resist a tilting tendency of t e insulator under cantilever load forces and to sustain the compression forces in the shell 4.

Slight longitudinal relative movement of the telescopically related members3 and 4, which may occur under the lateral bending tendency, is compensated for and permitted by the cushioning gaskets 22 and 31 and the sleeve 6.

The arrangement of parts, whereby the bolt heads 28' are disposed in the recesses 27 and the discoidal portion 9 of substantially the same diameter as the lower end of the shell 4, gives the insulator a relatlvely great flashover distance in consideration of the amount of material used and permits the insulator to be smaller for a given voltage.

The provisionof'the relativel soft insu- I lating sleeve 6, which is poure tion while hot, precludes the formation of air pockets and, being nonconducting, in contradistinction to the cements usually employed, permits the insulator to be entirely insulating over a greater pro ortionate distance than insulators hereto ore employed.

The arrangement of parts whereby the column 3 is entirely enclosed and anchored to the projections 14 and 21 renders the column flame proof and'prevents relative slippage of the parts.

into posi- Ill 'The insulator is, in general, an im rovement over other insulators previous y lemployed and, while I have shown and described but one form of the invention, changes may be effected-therein without departin from the spirit and scope thereof, as set orth in the appended claims.

I claim as my invention: 1. An, 'nsulator comprising a central ino sulating column of substantially frusto-. conical shape, a base member having a central projecting portion embedded in the larger end of said column and a laterally extending flange, a terminal member having a central projecting portion embedded in the smaller end of said column and a laterally projecting flange, and a tubular insulating member surrounding said column between said flanges.

2. An insulator compnsing spaced terminal members having substantially parallel plane discoidal portions and central longitudinal anchor portions projecting toward each other, one of said members being adapted for mounting on a rigid base, a

' substantially frusto-conical bod of insulating material molded about and tween said anchor portions, a refractory insulating tube surrounding said body in slightly spaced relation to said body and to said discoidal portions, a sleeve of yieldable inv sulating material between said body and said tube, and yieldable material between said tube and said discoidal ortions.

In testimony whereof, I ave hereunto subscribed my. name this 30th day of March, 1927. WALTER'H. SCHRAMM.

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