US1777071A

US1777071A - Insulator

Info

Publication number: US1777071A
Application number: US102069A
Authority: US
Inventors: George A Burnham
Original assignee: Condit Electrical Manufacturing Corp
Current assignee: Condit Electrical Manufacturing Corp
Priority date: 1926-04-14
Filing date: 1926-04-14
Publication date: 1930-09-30
Anticipated expiration: 1947-09-30

Description

Sept. 30, 1930.

G. A. BURNHAM 1,777,0714

INSULATOR Filed April 14, 1926 Patented Sept. 30, 1930 UNITED sTATEs PATENT OFFICE GEORGE A. BURNHAM, F SAUGUS, MASSACHUSETTS, ASSIGNOR TO CONDIT ELECTRICAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A'CORPOBA- TION OF MASSACHUSETTS INSULATOB `Application led April. 14, 1926. Serial N0. 102,069.

This invention relates to electric insulators, as insulating bushings, especially adapted, although not necessarily limited for use in high tension switches.

The terminals of an electric switch must have sufficient spacing to prevent lash-overs between them, and where air is the insulating medium, the terminals must necessarily be spaced widely apart to provide suicient insulation', if high voltages are employed. To provide the requisite spacing with vertically disposed insulating bushings would necessitate switch casings of Va prohibitive size; so it has been common practice to obtain the desired spacing at the terminal and of the bushing by inclining the bushings outwardly. This construction, while providing an increased spacing at the top of the insulator, must necessarily decrease the spacing at the lower end of the insulator. Toa certain extent this may be permissible since the lower exposed terminals of the insulator are immersed in oil; but it is evident that if the bushings are inclined to any great extent,

the lateral dimensions of the switch casing must be increased to maintain a safe spacing of the lower terminals.

Consequently an objectof this invention is the provision of an insulator so arranged that, when two or more of them are used in an electric switch or other similar apparatus, a suitable close spacing is provided between them at the lower ends thereof under the oil while a suitable wide space is provided between them at their upper and air-exposed ends.

A further object of this invention is generally to improve the construction of electric insulators.

Briefly the insulator embodying my invention comprises two angularly-related insulator-sections connected rigidly together, with a conductor extended therein which is composed of two angularly-inclined sections which correspond with and lie within said singularly-related insulator sections.

Certainfeatures of this invention are described and claimed in my co-pending application Serial No. 102,071 filed April 14,

1926. The broad idea of a flexible insulated cable within an enclosing casing', at least a part of which is insulating, is described and claimed in my copending application Serial No. 729,625, led August 1, 1924. 7

Fig. 1 is a sectional elevationthrough an insulator embodying the invention.

Fig. 2 is a sectional elevation through an electric switch having insulators with which this invention is particularly concerned.

Fig. 3 is a modification of the insulator of Fig. 1;

The insulator embodying the invention is of the bushing-type and comprises the straight upper tubular insulator body or shell 10 and the straightv lower tubular insulator-body or shell 12. Said upper shell is adapted to be exposed to the atmosphere and is provided with a plurality of petticoats 14 as is usual practice. Said lower shell is adapted to be immersed in oil or other insulating or arcquenching iluid and may be provided with a plurality of corrugations 16, as is usual practice. Both shells are provided with conductor-passages 18 therethrough and both may have attaching

flanges

22 and 23 cementedv to their lower and upper ends, respectively. Said upper and lower shells are secured to the opposite ends of a tubular metal connecting member or tube 20 and the flanges of said insulating bodies are attached by bolts 24 to

flanges

26 and 28 provided at the opposite ends respectively of said tube. In accordance with the invention said tube is suitably bent intermediate its ends to follow a regular curve and to provide angularly-related upper and lower sections so that said insulating shells are angularly inclined with respect to each other.

The conductor-structure for the insulator preferably comprises a section 30 of commercial high-tension` electric cable as set forth in my co-pending application Serial No. 729,625, filed .August 1, 1924. Said cable comprises a central conductor 32, which preferably is stranded, a body of insulating material 34, as superimposed layers of paper, on the conductor, and a lead protective sheath 36 enclosing the insulating material. The cable-section is of suitable length and diameter to enter the insulator-structure and is bent to conform with the shape of the insulator and to lit snugly therein. The lead sheath is removed from the ends of the cablesection, as indicated, leaving a section of the sheath at the middle of the cable and exposing the insulation at the ends. Some of theexposed insul tion is removed to pro- V vide surfaces which taper from the lead sheath to the exposed ends of the conductor, as indicated at 34. rihe conductor-structure thus formed is received within the insulatorstructure in the manner illustrated in l. The'lead sheath is received within the bent connector tube 2O and is approximately' co-eiitensive therewith and may be grounded thereto in any suitable manner not necessarily shown. rEhe tapered end-portions are received within the insulator shells 10 and l2. The exposed ends of the cable-conductor may be connected with suitable terminalmembers carried by the ends of the insulator-bodies l0V and l2. As here shown, a lug 38 is received the lower open end of the insulator-body 12 and has a recess therein in which the exposed lower end of said conductor is received and soldered. Said lug has a reduced and enteriorly screw-threaded extension 42 which extends loosely through a metal ferruleor capcemented to the lower end of said insulator-body.v A suitable terminal-member ehi, herev shown as a Contact bloclr for an electric switch, is screw-threaded on said extension 42. Lock-nuts 46 serve to loch said Contact block in place and said lug to said cap 4:0. ri`he upper end of the insulator may be arranged in a similar manner except that the lock-nuts 46 are preferably arranged to clamp va. circuit-lead between them.

. lf desired, the insulator may be filled with an insulating medium, as oil or a compound, through. the filler-plug 48 which is screwthreaded in the metal shell 20. Y

The upper flange 26 of said shell is extended outwardly beyond the flange 22 and is adapted to be secured to a support 60, as a switch casing, by suitable bolts 50.

7Eig. 2 illustrates the application of a pair of the insulators above described to the casing of a high-tension electric switch having' a switch frame which is secured to and comprises a cover for the oil receptacle 62. rlhe top wall of said casing is formed with apertures `64 through which a pair of insulators are passed and are fixed to the casing by bolts 50. Said insulators are so arranged Y in the switch casing that the upper portions thereof are inclined upwardly and outwardly, whereby to separate the exposed upper terminals widely thereby to prevent flash- Aovers therebetween. The lower portions of said .insulators are relatively closely spaced and are parallel and vertical. The oil level a-a in the casing is adapted to be above the lower end of the metal shell 20, or at least above the lower end of the insulator-flange 23, which is at casing or ground potential. i movable switch member 65 cooperates with the contact blocks lll carried by the lower ends of said insulators and the operating mechanism 65a for said movable switch member is contained in a mechanism-well 66 which is disposed between said insulators and between the divergent portions thereof.

ils thus arranged the lower ends of the insulators may be as closely spaced as is desirable, with the upper ends of the insulators widely spaced, and yet the casing dimensions may be made smaller than is practicable with the usual straight and inclined insulators, thereby resulting in a compact and economical structure.

For some purposes, l may replace the cablesection of the insulator with a bare bent rod 68, see Fig. 3, which rod is extended through the ends of the insulator and is connected with the terminals thereon, and lies approximately axially within the insulator and free from the side walls thereof. The insulator is adapted to be filled with an insulating medium, whereby to insulate the rod from the metal shell 20. An insulating spacer-member 70 may be disposed on said rod, at the bent portion thereof, and engage with. said metal shell, whereby to cooperate with the ends of the insulator in holding said rod in position. Said spacer-member 70. may have passages 7 2 therethrough, through which the insulating medium may pass.

The construction may be otherwise modified without departing from the spirit of the invention.

I claim.:

l. A bushing-type electric insulator having angularly related sections, a terminal connector carried at the end of each of said sections, and a correspondingly-shaped continuous conductor contained in said insulator and connected with said terminal connectors and a similar insulator having Va section thereof in divergent relationship with the similar section of said first mentioned insulator.v

2.V A bushing-type electric insulator having angularly-related sections, each section having an end terminal connector, a correspondingly-shapedr conductor contained therein and connected with said terminal connectors, and an attaching member intermediate the ends of said insulator and a similar insulator having a section thereof in divergent relationship with the similar section of said iirst mentioned insulator.

8. A. bushing-type electric insulator having a bent shell, straight insulator bodies carried by the opposite ends of said shell, and a bent conductor disposed within said shell and insulator-bodies, and a similar insulator having a section thereof in divergent relationl G il llt! ship with the similar section of said first mentioned insulator.

4. A bushing-type electric insulator having a bent metal shell, straight insulator bodies carried by the opposite ends of said shell, a bent conductor disposed within said shell and insulator-bodies, and an attaching member carried by said metal shell, and a similar insulator having a section thereof in divergent relationship with the similar section of said first mentioned insulator.

5. A bushing-type electric insulator `comprising a tubular connecting-member having relatively-inclined end-sections, .and straight 3 insulator-bodies carried by said inclined endsections, and a similar insulator having a section thereof in divergent relationship with the similar section of said first mentioned insulator.

6.7A bushing-type electric insulator comprising a tubular connecting-member having relatively-inclined end-sections, and straight insulator-bodies carried by said end-sections and having passages therein aligned with the passage in said connectingmember, and a similar insulator having a section thereof in divergent relationship with the similar section of said first mentioned insulator.

7. A bushing-type electric insulator cornprising a tubular connecting-member having relatively-inclined end-sections, straight insulator-bodies carried by said inclined end-sections and a conductor extended through said insulator-bodies and connecting member and insulated from said connecting-member, and a similar insulator having a section thereof in divergent relationship with the similar section of said first f mentioned insulator.

8. A bushing-type electric insulator coming shells carried by the ends of said tube, a bent conductor extended through said tube and shells, and means engaging said conductor Within said tube arranged to hold it from contact with said shell, and a similar insulator having a section thereof in divergent relationship with the similar section of said first mentioned insulator.

9. A bushing-type electric insulator comprising a bent tube, straight insulating shells carried by the ends of said tube, a bent conductor extended through said tube and shells, and an insulating medium surrounding said conductor, and a similar insulator having a section thereof in divergent relationship with the similar section of said first mentioned insulator.

10. A bushing-type electric insulator comprising akbent metaltube, straight insulating shells carriedby the ends of said tube, a bent conductor-structure contained within said tube and shells comprising a conductor extended through said tube and shells,

ductor and extended through said tube and shells and having tapered end-portions disposed Within said shells, and a metal sheath carried by said insulating body and contained mainly Within saidtube.

12. A bushing-type electric insulatorcom- `prising a bent metal tube, straight insulating shells carried by the ends of said tube, and a bent conductor-structure contained Within said tube and shells comprising a bent conductor extended through said tube and shell, and a bent body of insulation carried by said bent conductor, and a similar insulator having a section thereof in divergent relationship with the similar section of said first mentioned insulator.

13. An oil-filled bushing-type electric insulator comprising a continuous tubular structure having insulating end-portions which are inclined out of a straight line, terminal connectors disposed at the ends of said insulator and arranged to provide an oil-tight closure thereat, and an attaching member intermediate its ends, and a similar insulator having a section thereof in divergent relationship With the similar section of said first mentioned insulator.

14. A bushing-type electric insulator comprising a bent metal` tube having outstanding flanges at its opposite ends, straight insulator shells disposed on the opposite ends of said tube, said shells having flanges fixed thereto, and means securing said flanges to said tube-flanges, one of said tube-flanges outstanding beyond its cooperating shellflange for attachment to a support, and a similar insulator having a section thereof in divergent relationship With the similar section of said first mentioned insulator.

In testimony whereof, I have signed my name to this specification.

GEORGE A. BURNHAM.