US2442165A - Insulator - Google Patents

Description

y 1948. K. N. GEROW 2,442,165

INSULATOR Filed Dec. 28, 1944 2 sheets sheet 1 mvautoe K. N. GEROW May'i5j1948.

INSULATOR Filed Dec. 28, 1944 2 Sheets-Sheet 2 IN V E N T 0 R rsyf- Arrome'vs' Patented May 25, 1948 INSULATOR Kenneth N orris- Gerow, Beileville, Ontario, Canada Application fiecember 28, 1944, Serial No. 570,504

Claims. 1

The invention relates to insulators as described in' the present specification and illustrated in the accompanying drawings that form a part of the same.

The invention consists essentially of the novel features of construction as-pointed out broadly and'speoifically in the claims for novelty following a descripti'on in detail'of acceptable forms of the invention.

=The objects of the invention are to devise a means for supporting and holding power or telephone lines and cross-arms or other supporting members in such a way that itwill prevent any lateral'or longitudinalmovement of the wire or wiressupported, and avoiding the necessity of using intermediary fastening means, consequent- ;lyminimizing surface leakage paths and overcoming mechanically high stressed concentrations which are'set up by ordinary conductors at thetie; to furnish a means which will act as a shed and'protect the conductor from inclemencies of theweather; to reduce wire loads on pole structures and ensure uniform conductor tension between dead ends and facilitate conductor changes or rearrangements in replacing the wire or transferring it from one position to another; andgenerally to provide an insulator that Will be economical to manufacture, simple in construction, durable in use, and efficient for its purpose.

In the drawings:

Figure 1 is a fragmentary perspective view of the upper portion of a pole and crossarm and having the insulator secured thereto.

Figure 2 is'an enlarged cross-sectional view takenadjacent the point of attachment of the insulator to the cross-arm.

#Figure-3-'is a sideelevational view of the insulator.

"Figure 4- is a top plan View ofthe insulator.

Figure 5 is an underside plan view of the insulator.

Figure 6 is a longitudinal sectional view of the insulator.

Figure 7 is an end view of the insulator.

Power and telephone line insulators in common use today have several functional weaknesses inherent in their construction. These might be stated briefly as follows:

They are mounted on crossarms or on suspension arrangements in exposed positions to the extent that under severe conditions of heavy rain a large proportion of the leakage path is of no value. For example, the pin type under severe rain conditions is a type where the insulation is dependent entirely on the leakage path under 2 the skirt. The effectiveness of this is further reduced by rain bouncing on the arm or carried by wind and being deposited over the underskirt path.

The conductor-is tied with a length of wire to the insulator. This is unsound electrically-and mechanically. The use of this tie in effect puts in parallel all surface leakage paths and reduces the efiiciency of thedesign. Mechanically high stress concentrations are set up on the conductor at-the tie,-resulting in ultimate failure.

It is -diflicult in any event to provide a tie hav ing good holding power. The objections from an electrical leakageviewpoint areapplicableto the important requirement of flashover. Here again rain conditions are controlling and the adequacy of the insulators is seriously reduced under these conditions. Considered as a whole, the pin type insulator mounted on a crossarm is a poor design since under emergency mechanicalloadconditions it is subject to severe bending stress which few pins can withstand without distortion unless double crossarms, pins, ties and insulators are used. Many other objections to the modern design can'be-named.

It is, therefore, the aim of this invention to provide a solution to'the various objections as herein-before mentioned and, although modifications andramifications may be made without departing from'the essential features ofthe invention, the following is an acceptable form of the insulator for accomplishing the many purposes.

Like numerals of reference indicate corre- SlOOlldillg parts in the'various figures.

Referring-to the drawings, the insulator consists of a tubular unit and is formed of porcelain, glass or other suitable material and has the central body it! and the enlarged end portions l I and i2 from which extendthe protective shields I3 and i l and the integral side brackets'lii and it provided with bolt holesll and 48. The side brackets form the means-for fastening the insulator to the crossarm I9 of the pole 20.

The underside of the central body I0 is recessed at 2i and forms the outside diameter of the central part of the body and which is smaller in diameter than the end pieces which are necessarily larger because of the end projection design.

A recess 3| is formed in the central body of the insulator and is for the purpose of receiving the snub or sleeve 22. This snub is in split form and of a well known type. The line wire 23 is drawn up to proper tension on top of the cross arm, the location of the snub marked thereon, then the split snub is pressed on the wire at the point and forms a lump Or swelling on the line wire itself at the point designated by the tensioning procedure. The insulator is then placed under the wire so that the snub is just above the recess in the insulator body and the insulator twisted onto the Wllfi.

The snub or sleeve is simply pressed onto the wire at the desired point by means of a pressing tool of the type commonly in usein powerline construction work. The intimacy of the contact between the snub and the wire is such that the wire will break before the snub would be displaced. The length of the snub need not be more than convenient and would generally be approximately the wire diameter.

The insulator is provided with a radially disposed spiral or skewed slot 25 which extends from one enlarged end portion ll through the central channel 28 of the central body I and to the other enlarged end portion I2; in other words, the spiral or skewed slot extends throughout the entire length of the insulator.

The central channel is adapted to receive the wire and terminates in the extensions 21 and 28 and which are formed integral with the insulator body.

The feature of the protective shields is for the purpose of providing shelter for the, insulator body and by means of the brackets, which are integral therewith, furnish the means for mounting the insulator beneath the crossarm.

, In the actual mounting ofthe insulator to the crossarm, the insulator is wound or twisted onto the wire and, when the wire is in place, it is supported and restrained from movement in all directions in a plane at right angles to the wire itself because of the nature of th slot.

The wire is snubbed and the snubbed portion is inserted in the recess 3| in the central body of the insulator.

The insulator is then mounted beneath the crossarm and held thereto by means of a bolt 29, which extends through the brackets and through the crossarm, and a nut 30.

It will, therefore, be seen that there is provided a greater crossarm strength for the standard cross sections than are available with the ordinary designs of pin type mounted insulators and, consequently, will permit such standard cross sections of the crossarms to be reduced without lessening the factor of safety.

In respect to securing the insulator to the the crossarm, it will be understood that various means may be used apart from the bolt and nut fastening as already mentioned; for example, a strap bracket could be used, the strap bracket fitting over the crossarm section and bolted to the insulator by standard pins, the latter engaging with suitable protuberances for that purpose.

What I claim is: y

1. An insulator comprising a central body having a recess on its upperside enlarged end portions extending from said central body, said body' and end portions having a radially located spiral or skewed slot, a snub secured to a wire, the said slot in the insulator being so constructed and arranged as to be wound or twisted onto the wire in such a manner that the wire will engage in said slot and said snub will engage with the said recess, and means for securing said insulator to a suitable support. 1

2. An insulator comprising a central-body and enlarged end portions, a recess in the upper side of said body, said body and end portions having a radially disposed spiral 0r skewed slot, said slot being so constructed and arranged as to permit the said insulator to be wound or twisted on a wire, a snub adapted to be secured to a wire and to engage in said recess, and means for securing said insulator to a suitable support.

3. An insulator comprising a central body and enlarged end portions,'said body and end portions having a radially disposed spiral or skewed slot, the said slot being so constructed and arranged with respect to the said insulator as to allow the insulator to be wound or twisted .on a wire, a snub attachable to a wire for preventing longitudinal movement of said wire, a recess in the top of said body engaging with said snub, and means for securing said insulator to a suitable support.

4. An insulator comprising a central body having enlarged end portions and a recess in its upper side, the enlarged end portions projecting outwardly from said centrol body, shields formed by extensions of said end portions, brackets extending upwardly from said end portions, a spiral or skewed slot extending from one end portion across the upper side to the other end portion, said slot being so constructed and arranged with respect to said insulator as to permit the insulator to be wound or twisted onto a wire, a snub attachable to a wire and adapted to engage in said recess, and means for securing said insulator to a suitable support.

KENNETH NORRIS GEROW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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