US2840631A

US2840631A - Animal guard for electrical equipment

Info

Publication number: US2840631A
Application number: US422767A
Authority: US
Inventors: Harold C Marcroft
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-04-13
Filing date: 1954-04-13
Publication date: 1958-06-24
Anticipated expiration: 1975-06-24

Description

June 24, 1958 H. c. MARCROFT ANIMAL GUARD FOR ELECTRICAL EQUIPMENT Filed April 13, 1954 ATTORNEYS United StatesPatent O ANIMAL GUARD FOR ELECTRICAL EQUIPMENT Harold C. Marcroft, Baltimore, Md.

Application April 13, 1954, Serial No. 422,767

3 Claims. (Cl. 174-140) This invention relates to insulators or electrical bushings such as used on transformers, circuit breakers, capacitors, and the like, and in particular a disc of ceramic, plastic, or other suitable material having a conducting band providing a rim around the outer edge and having an impedance, such as a resistor or condenser connecting the band with a clamp or other means to the electricalconducting stud of the bushing.

The purpose of this invention is to reduce damage to electrical bushings due to an electric power are caused by a flash of lightning or by an animal standing upon a tank of the apparatus and touching the bushing cap, where the electric system in which the parts are included is grounded at some part of the installation, such as the neutral terminal of an associated transformer, in a system known as a grounded neutral system.

An animal standing on the tank of a transformer or the like and touching the bushing cap causes an electric power are or short circuit which damages both the bushing, the cap of which is engaged by the animal and similar bushings of associated equipment, and consequently, causes extensive power interruptions. With this thought in mind this invention contemplates a shield or guard positioned over the live cap at the upper end of an electrical bushing, the rim of which guard is connected by an impedance to the main stud of the bushing, whereby the possibility of an animal standing on the tank of the equipment and touching the bushing cap or live conductors is substantially eliminated.

The object of this invention is, therefore, to provide means for forming and installing guards or protecting shields over electrical bushings of a transformer or the like whereby an animal, such as a squirrel will engage a guard or shield instead of the bushing.

Another object of the invention is to provide a guard for preventing animals contacting electrical equipment in which the guard is adapted to be installed on equipment now in use.

Another important object of the invention is to provide a protecting guard for an electrical bushing whereby beneficial eifects from lightning flashovers are attained and wherein an animal contacting the guard is killed or receives a severe jolt so that the possibility of further attempts to contact the bushing is substantially eliminated.

A further object of the invention is to provide an animal guard for electrical equipment, such as bushings in which the device is of a simple and economical construction.

With these and other objects and advantages in view the invention embodies a disc of insulating material having a continuous conducting band on the peripheral edge with clamping elements secured to the disc and adapted to suspend the disc from the bushing stud or cap, and a resistance or other impedance connected between the band and the main connection of the bushing, by a clamp or otherwise.

Other features and advantages of the invention will appear from the following description taken in connection with the drawing, wherein:

Figure 1 is a plan view looking downwardly upon the upper end of an electrical bushing showing a guard positioned over the bushing and also showing the guard with a rim thereof connected by means of an impedance to the terminal of the bushing,

Figure 2 is a side elevational view of the electric bushing shown in Fig. 1 showing a guard mounted on the bushing, the guard and clamping elements thereof being shown in section, and the parts being shown on an enlarged scale.

Figure 3 is a side elevational view similar to that shown in Fig. 2 illustrating a modification where the impedance or resistance is replaced with a conducting glaze on the upper surface of the guard and wherein the parts are shown on a reduced scale.

Referring now to the drawing wherein like reference characters denote corresponding parts the improved electrical bushing or insulator guard of this invention ineludes a disc 10 of insulating material having a rim 11 of material providing a good electrical conductor extended around the peripheral edge, a cup-shaped element formed with sections 12 and 13 clamped to a terminal or stud 14 of a bushing 15 and a resistance or other impedance 16 connected to the rim 11 by brazing or the like or with a bolt or rivet 17, and also connected to the electrical conducting stud 14 such as by a bolt 18 of a clamp formed with U-shaped sections 19 and 20 and secured in clamping relation with the stud with

bolts

21 and 22, the bolt 21 extending through flanges 23 and 24 and the bolt 22 through flanges 25 and 26.

The edge of the section 12 of the supporting element of the disc 10 is connected to the insulator by suitable means, such as with a flange 27 that is embedded in the disc 10 and in this arrangement the upper part of the section is provided with flanges 28 and 29 that are secured to corresponding flanges 30 and 31 of the section 13 with bolts 32 and 33. The lower edge of the section 13 is also provided with a flange 34 that is embedded in the material of the disc 10.

In the design illustrated in Figure 3 a disc 35 having a rim 36 is secured to a stem 37 of a bushing 38 with clamping elements 39 having bolts 49 and 41 extended therethrough, similar to the elements 12 and 13 whereby the disc 35 is secured over the insulator or bushing. In this design the upper surface of the disc 35 is coated with a glaze, as indicated by the numeral 42 which provides resistance thereby performing the function of the resistance of impedance 16, of the design shown in Figures 1 and 2.

The guard may be provided in different designs to cover insulators or bushings of different types and designs and the guards may be secured over the bushings or insulators by other suitable means. Other means may also be used for providing resistance or impedance to replace the resistance 16 or the glaze 42.

It will be understood that other modifications, within the scope of the appended claims, may be made in the design and arrangement of the parts without departing from the spirit of the invention.

What is claimed is:

1. In a guard for electrical equipment, the combination which comprises an insulator including a bushing having a plurality of sections and having a stem extended upwardly therefrom, a cup-shaped element mounted on the stem and extended over the inner hub portion of the uppermost section of said bushing, a disc of insulating material carried by the cup-shaped element, a rim of material capable of conducting electricity mounted on the periphery of the disc, a clamp secured to the stern 3 r and spaced upwardly above the upper end of the bushing, and an impedance extended from the rim of the disc to the clamp on the stem of the bushing.

I In a guard for electrical equipment, the combination which comprises an insulator including a bushing having a plurality of sections and havinga stem extended upwardly therefrom, a split cup-shaped element mounted on the stem and extended over the inner hub portion of the uppermost section of said bushing, said cup-shaped element having a flange extended from the lower edge, a

disc of insulating material positioned on the flange of the V cup-shaped element and extended horizontally therefrom, a rim of material capable of conducting electricity mounted on the periphery of the disc, a clamp secured to the stem and spaced upwardly above the upper end of the bushing, and an impedance extended from the rim of the disc to the clamp on the stem of the bushing.

3. A guard for insulators or electrical bushings comprising a disc of insulating material, a continuous rim of conductive material extended around the peripheral edge 20 0f the disc and overlapping the edges of upper and lower surfaces thereof, a stud extended upwardly from the central portion of the bushing, an inverted cup-shaped element extended upwardly from the central portion of the disc, over the central portion of the bushing, and positioned to be clamped around the stud extended upwardly from the bushing for suspending the disc above and in spaced relation to the bushing, a clamp mounted on the stud and spaced upwardly from the inverted cup-shaped element, and a resistance positioned with the upper end connected to the clamp spaced above said inverted cupshaped element and with the lower end connected to the rim on the periphery of the disc.

References Cited in the file of this patent UNITED STATES PATENTS 1,166,393 Steinberger Dec. 28, 1915 1,766,636 Holzel June 24, 1930 FOREIGN PATENTS 813,720 Germany Sept. 17, 1951