US 3019287 A
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Description (OCR text may contain errors)
Jan. 30, 1962 C. B. NEWCOMB, JR., ETAL BUSHING COVER 2 Sheets-Sheet 1 Filed Sept. 17, 1959 Jan. 30, 1962 c. B. NEWCOMB, JR., ETAL 3,019,287
BUSHING COVER Filed Sept. 17, 1959 2 Sheets-Sheet 2 W l m-m Filed Sept. 17, 1959, Ser. No. 840,659
2 Claims. or. 174-138) This invention relates to covers for electrical parts, and more particularly to covers for transformer bushings such as extend upward from the top of a polemounted transformer and have a conductor extending laterally therefrom, adapted to protect the bushing connections (as the term is used to include the bushing proper, the bushing hardware and the conductor leading therefrom) from being shorted by animals and birds. In the coassigned copending application of Cyrus B. Newcomb, Jr., Serial No. 833,615, filed August 13, 1959, entitled Bushing Cover, there is disclosed a protective cover particularly for use on a vertical transformer bushing having a conductor (such as a jumper wire) extending upward from the bushing. The cover shown in that application is cone-shaped, being adapted to surround a vertically extending conductor and capable of being bent to some extent for application to conductors which are angled to some extent from vertical. This cone-shaped cover, however, is not particularly suitable for use on a bushing from which the conductor extends laterally (i.e., horizontally or angled up to about 45 one way or the other from horizontal) and among the several objects of the invention may be noted the provision of a cover for protection in such cases against power outages such as may be caused by grounded animals (such as squirrels, opossums or raccoons) or birds coming into contact with the energized bushing connections and causing a short.
A further object of the invention is the provision ofa cover such as described which may be'quickly and easily applied to a bushing, without any necessity for disconnection of the conductor (such as a jumper wire) extending from the bushing, the cover simply being snapped into place and being inherently self-adjusting on' the bushing to hold its position thereon, and being adapted to accommodate itself-to various lateral jumper wire positions.
Another object of the invention is the provision of a cover such as described which is repellent by scent and taste to animals and birds and which has such electrical properties as to produce an electrical tickle sufficient to repel small animals but not suflicient to be dangerous to linemen and far below the requirements to activate a station breaker or branch line equipment.
. A further object of the invention is the provision of a cover having the above characteristics which is economical to manufacture, has a smooth self-cleaning finish that resists all kinds of weather, never needs attention and which is capable of lasting for the normal life of a transformer.
Other objects and features will be in part apparent and in part pointed out hereinafter.
The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.
In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,
FIG. 1 is a view in side elevation of a mold used in manufacturing covers of this invention;
FIG. 2 is a view like FIG. 1 showing the mold with a plastic body molded thereon;
FIG. 3 is a bottom plan view of FIG. 2 illustrating certain cutting operations;
FIG. 4 is a cross section taken on line 4-4 of FIG. 2;
FIG. 5 is a view in side elevation showing a further step in the manufacture of a cover;
cited States Patent 0 i Patented Jan. 30, 1962 Cti FIGS. 6 and 7 are crosssections taken on lines 6-6 and 77, respectively, of FIG. 5; and,
FIG. 8 is, a perspective illustrating a completed cover in use on a transformer. Y
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
Referring to the drawings, FIGS. l-7 illustrate one possible mode of making covers of this invention, utilizing a metal mold such as indicated at 1, and shown per se in FIG. '1. This mold, as illustrated, resembles .a tobacco pipe in shape, having an approximately cylindrical solid body portion 3 with a rounded end portion 5 and an elongate stem 7 extending laterally from the rounded end portion 5. Stem 7 is preferably tapered from the juncture with body portion 3 out to it free outer end, and is preferably angled upward, as appears in FIG. ,1.
Mold 1 is utilized for molding a body 9 (see FIGS. 2-4) of a plastic material from which the covers are to be made. Thismay be accomplished, for example, by dipping the mold in a suitable plastisol. An example of a plastisol that maybe used is one comprising polyvinyl chloride dispersed in a liquid such as 2-ethylhexylphthalate. Preferably, in forming body 9 on the mold 1 as aforesaid, the mold is first heated to between 230 500 F., depending on the viscosity of the plastisol, and the heated mold is dipped into the plastisol and allowed to remain therein for a sufiicient time and withdrawn in such manner as to develop a coating of the desired thicknessthereon, this coating constituting body 9. The mold 1 withthe body 9 thcreon, after withdrawal from the dip, is baked in an oven at a temperature and for a time sufiicient forthebody 9 to become of rubber-like consistency. In the case of the use of the stated polyvinyl chloride plastisol, the baking temperature is about 400 F. and the time about twenty minutes.
Body 9 on mold 1 also has the form of a tobacco pipe, with a hollow approximately cylindrical portion 11 having a rounded end portion 13 and a hollow stem por tion 15 extending laterally from the rounded end portion 13. As shown in FIG. 2, body 9 has a circular portion 17 covering the bottom of portion 3 of the mold, but the hollow stein porti0n15 of body 9 stops short of the free end of mold stem 7. Portion 17 of the molded body 9 is" cut off at the line CC indicated in FIG. 2, and body 9 is also slit as indicated at 19 from its resultant edge at the bottom of portion 11 thereof all the way to its edge at the free end of its stem portion 15. This slit is made in the bottom of stem portion 15 of the molded body 9 as viewed in FIG. 2, and along the side of portion 11 toward the stem portion 15. p p
The above-described cutting and slitting operations are carried out while the molded body 9 is still hot from the oven. Immediately thereafter, body 9 is removed from the mold 1 by spreading it open (this being possible because of the provision of the slit 19). With the molded body 9 still hot from the oven, it is then placed on a form 21 (see FIGS. 5-7) which corresponds in shape to the.
shape of mold 1 but which is of smaller dimensions in certain respects than the mold 1. Thus, the form 21 has an approximately cylindrical portion 23 of smaller diameter than portion 3 of mold 1 (but approximately the same height as mold portion 3) and a tapered stem portion 25 of smaller diameter both at its root and at its free end than mold stem (but approximately the same length as mold stem 7). As the hot body 9 is placed on the form 21, its margins along the slit 19 are overlapped as indicated at 9a. A piece of paper 27, such as kraft paper, is sandwiched between the overlapping margins 9a to prevent them from sticking together. The body 9 is allowed to cool while on the form 21, as a result of which it takes a set in form in which it was applied to the 3 form 21, and acquires elastic memory by reason of which it tends to revert to its set form when deformed therefrom. The paper 27 may then be stripped away, or allowed to remain in place until the time of use, and then stripped away.
The resultant tobacco-pipe-shaped body constitutes a cover C of this invention. As will be apparent, cover C comprises a hollow body of flexible plastic material having a cap portion 11 and an integral hollow stem portion 15 extending laterally from the top of cap portion 11. The hollow stem portion 15 opens into the cap portion and is open at its outer end. The cap portion is split on the side thereof toward the stern portion and the stem portion is split throughout its length and in continuation of the split in the cap portion. Both the cap and stem portions have overlapping margins 9a where split. In a typical cover, the cap portion 11 is about 3 /2 inches high with an internal diameter of about 2% inches. The stem portion 15 is about 11 inches long with an internal diameter at its root of about inch tapering down to about /2 inch at its free end. The cap portion is about ,5 inch thick and the stem portion diminishes in thickness from about x A inch at its root to about A inch at its free end. There is about 1% inches of overlap at 9a in the cap portion and about inch of overlap at the free end of the stem portion.
FIG. 8 shows a cover C applied to a vertical bushing 31 on the cover 33 of a transformer 35. The cover C is applied simply by spreading it open, placing the cap portion 11 thereof around the upper part of the bushing 31 and placing the stern portion 15 around the conductor 37 (such as a jumper wire) extending laterally from the bushing, and then releasing the cover, whereupon by reason of the elastic memory of the plastic, the cover returns toward its initial tobacco-pipe-shaped form and wraps itself around the upper part of the bushing and the conductor. With the overlap at 9a in the cap portion 11, the cover is applicable to bushings of various sizes, with complete coverage to prevent an animal or bird from causing a short between the connection on top of the bushing or the conductor 37 and the cover of the transformer. The cover will not turn or slip. FIG. 8 also shows a lightning arrester hole 39 cut in the cap portion 11 of the cover. The dotted line positions of the stem portion 15 of the cover shown in FIG. 8 are exemplary of bent positions of the stem portion which are possible due to its flexibility to accommodate conductors extending laterally at various angles.
The cover, as made of polyvinyl chloride, is repellent by scent and taste to animals and birds and permits a small amount of current leakage which is suflicient to repel the small animals and birds, but which is not dangerous to linemen and which is far below the leakage required to activate circuit breakers or other power line equipment. This material is also highly weather-resistant and long-lasting.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above con- 4- structions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
1. A cover for application to a transformer bushing and a conductor extending laterally from an end of the bushing to provide protection against animals such as squirrels and birds, comprising a hollow body of flexible plastic material having an inverted cup shaped cap portion with a closed top adapted to cover said end of a bushing and an integral hollow stem portion of substantially smaller diameter than said cap portion extending laterally from the top of the cap portion, said hollow stern portion opening into the cap portion and being open at its outer end, said hollow stem portion being adapted to surround a conductor extending laterally from said end of the bushing, said hollow body being split from the edge of the cap portion to the junction of the stem with the cap and thence along the underside of the stern portion to its outer end, and having overlapping margins where split, said plastic material as formed into said hollow body having elastic memory whereby when deformed from its initial form it tends to revert to its initial form, said hollow body being adapted to be spread open for application of said cap portion around said end of a bushing and for application of said stem portion around a conductor extending laterally from said end of the bushing and then adapted by reason of its elastic memory to return toward its initial form and wrap itself around said end of the bushing and the conductor, the overlap of said margins in the cap portion being sufiicient for application thereof to bushings of different diameters, said flexible plastic material of said stem portion having a substantially smaller thickness than the thickness of the material of said cap portion and the thickness of the material of said stem portion decreasing substantially from the junction of the stem with the cap to the outer end of the stem, whereby said stern portion is adapted for bending up or down to accommodate conductors extending at an angle with the horizontal as well as to accommodate a horizontally extending conductor.
2. A cover as set forth in claim 1 wherein said plastic material is polyvinyl chloride, thereby imparting the characteristic of permitting a relatively small amount of current leakage sufficient to repel small animals such as squirrels and birds but far below that required to activate circuit breakers or other power line equipment.
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