Spiral Conductor Cover

Abstract

An improved electrical conductor cover is provided which is operable to be positioned in enclosing relationship to portions of highly energized conductors in order to protect linemen or other working in the vicinity thereof. The cover is fabricated from an elongated, continuous sheet of electrically insulative synthetic plastic material and is shaped to present a generally spiral cross section with inner and outer spirals of substantially equal length. Both the inner and outer spirals are configured to telescopically engage and interconnect with a complementary adjacent conductor cover or other piece of cover-up equipment such as insulator covers of varying types, without the need of separate connection structures. By virtue of the fact that the inner spiral extends the entire length of the cover and interconnects with a similar member of another conductor cover or other piece of cover-up equipment, a conductor received therein is completely encased in an insulative sleeve of plastic material without gaps along the length thereof, and consequently the cover is capable of effectively insulating conductors energized to very high levels.

Description

This invention relates to a device for protecting linemen or others from accidental contact with energized electrical conductors when working in proximity thereto. More particularly, it is concerned with a protective device of the type known generally in the art as a "spiral conductor cover" wherein an improved cover is provided which is adapted to fully enclose an energized conductor in insulating relationship thereto without the need of separate connection means joining adjacent covers.

As can be appreciated, lineman and others are often required to work live lines at elevated heights either on electrical poles and towers or in buckets of aerial devices where they are in close proximity to the energized electrical conductors. In such situations a hazard is produced by the proximity of the energized lines which prevents the linemen from working with their usual freedom of movement and speed, because of the constant fear of receiving shocks or burns as a result of accidental contact with the energized lines. Hence, in order to permit safe, more efficient working conditions in such areas, the energized conductors must be temporarily insulated, preferably by a quickly installable, removable protective device.

One type of protective device heretofore employed in this context is known as a spiral conductor cover. Such covers are formed from relatively thin insulative materials such as synthetic plastics and are shaped to present a generally spiral cross section. The innermost spiral of such covers is configured to partially wrap about an elongated conductor to suspend the entire device thereabout, with a spaced, outer spiral circumscribing the conductor to provide additional insulation. The convolution of the inner spiral portion is configured to provide an elongated space at least equal to the diameter of the conductor in order to provide a passageway for the latter for use during installation of the device. An extension normally attached to a relatively narrow, elongated tab or lip projecting from the outermost spiral portion facilitates manual positioning or placement of the cover about the conductor in order to introduce the latter into the inner passageway and into protected orientation within the concave face of the innermost spiral. This is normally accomplished by placing the cover on the conductor followed by shifting the cover about the conductor until the latter is properly disposed within the innermost spiral.

Since it is often necessary to insulate a relatively long section of an energized conductor, at least a pair of spiral covers are conventionally adapted to be interconnected by means of separate connection structures such as insulative collars or the like. Moreover, in order that the conductors be capable of covering portions of electrical lines supported by pin-type insulators, the inner and outer spirals adjacent the ends of the cover have normally had to be trimmed away in order to permit them to be slipped over such pin insulators in covering relationship thereto.

In practice, the spiral conductor covers described have been deficient in several important respects, particularly when it is attempted to employ the latter as a protective device above highly energized conductors.

First, since the insulative qualitites of the cover result from the nature of the sheet material employed, as well as the spacings between adjacent spirals, it can be seen that the common expedient of providing trimmed portions or gaps at the ends of the conductor covers seriously impairs the ability of the latter to effectively insulate highly energized power lines. This diminished insulative capacity is particularly pronounced at the points of interconnection between adjacent covers, and the covers are therefore most likely to fail at these areas; furthermore, during the normal performance of their duties, workmen will often be in close proximity to these points of greatest danger. Additionally, because of the separate connection structure normally employed, the prior art covers are expensive to buy and time consuming to install and remove from the conductors.

Therefore, there is a need in the art for a spiral conductor cover of continuous, one-piece construction which is capable of insulating highly energized conductors, and can be quickly and easily interconnected with adjacent covers without impairing the insulative function thereof.

SUMMARY

Accordingly, it has been found that the aforementioned problems and difficulties can be overcome by providing an elongated spiral conductor cover with a series of continuous spiral convolutions providing the requisite degree of insulation. The cover is fabricated from an elongated, continuous sheet of relatively thin, electrically insulative material and is shaped to present a generally spiral-like cross section with a series of connected, arcuate, spiral-like convolutions each spaced from the adjacent convolution a distance at least equal to the diameter of the conductor to be covered. Additionally, at least one end of the innermost convolution thereof is configured to telescopically receive and interengage with a complementally configured end of a like member of an adjacent protective device. The outer spirals thereof are preferably of a length equal to that of the inner spiral, and are likewise complementally dimensioned and arranged to interengage with an adjacent cover to provide a frictional, snap-fit connection therebetween. In this manner, the centrally disposed conductor within the confines of separate, connected spiral covers is completely encased by an insulative jacket without any gaps along the length thereof as was common in the constructions of the prior art.

In other preferred embodiments the cover has a single inner and outer spiral, with the former being radially enlarged at one end thereof for the purpose outlined above. Additionally, the outer spiral is flared at the end thereof adjacent the radially enlarged end of the inner spiral to present a female connection portion adapted to telescopically receive a complementally dimensioned male end of an outer spiral of an adjacent protective device to effect a snap-fit interconnection therebetween. The remaining distal ends of the respective sprials are also configured to interconnect with another protective device, such that each cover is provided with a male and female connection end on the respective spirals thereof. In the manner described, this allows a plurality of separate covers to be axially interconnected to provide a continuous insulated shield of any desired length along an energized conductor.

In still further preferred embodiments, an elongated, relatively narrow, generally radially extending tab portion is provided along the length of the cover adjacent the terminal end of the outer spiral, and an insulated, depending extension or handle means is attached thereto to facilitate installation of the device about an energized conductor. The tab portion is preferably integral with the outer spiral and is formed by folding back the extreme end thereof upon itself, thereby forming a portion having a thickness double that of the remainder of the device.

Complementary cover members are also provided for use in protecting segments of conductor proximal to supporting insulators or the like. In such instances a separate insulative synthetic resinous member is employed to cover the insulator and a short stretch of conductor extending from both sides thereof. The distal ends of such members are complementally configured to mate with the spiral conductor covers of the present invention in order to form a continuous, effective protective shield along the entire length of an energized line.

THE DRAWINGS

FIG. 1 is a side elevational view of a spiral conductor cover in accordance with the present invention with a flared female connection portion provided on the leftmost end thereof with a male connection portion on the distal end;

FIG. 2 is an enlarged, end elevational view showing the flared female connection portion of the conductor cover shown in FIG. 1;

FIG. 3 is a fragmentary, vertical sectional view taken along line 3--3 of FIG. 2, showing a radially enlarged inner spiral adjacent the flared female connection portion of the outer spiral;

FIG. 4 is a fragmentary, vertical sectional view showing a pair of connector covers in accordance with the invention interconnected together;

FIG. 5 is an elevational view partly in vertical section showing a pair of opposed conductor covers interconnected by means of a complementally configured insulative housing covering a conventional pin insulator assembly;

FIG. 6 is an end elevational view of a generally T-shaped insulator cover particularly adapted to cover and protect a post-type insulator; and

FIG. 7 is side elevational view partially in vertical section showing the T-shaped cover of FIG. 6 operatively disposed over a post-type insulator with the male ends of separate spiral conductor covers received within the distal female connection ends of the insulator cover.

DETAILED DESCRIPTION

A spiral conductor cover in accordance with the invention is shown in FIG. 1 and is generally referred to by the numeral 10. It is composed of a continuous sheet of relatively thin, electrically insulative synthetic plastic material and has a flared female connection end 12 on one end thereof and a male connection end 14 on the remaining end, the configuration of these ends being important for purposes to be made clear hereinafter. Additionally, a longitudinally extending, integral tab portion 16 extends generally radially away from the cover body and has an insulated, depending extension or handle 18 connected thereto.

As best shown in FIG. 2, the continuous sheet is shaped to present a generally spiral-like cross section and has an innermost spiral 20 with an outermost spiral 22 of substantially equal length connected thereto by generally planar segment 26. The spirals 20 and 22 are spaced apart a distance at least equal to the diameter of a conductor to be insulated, thereby providing an arcuate passageway 23 therebetween to facilitate installation of the protective device. Additionally, an elongated entryway 24 is provided between the terminal edge of outer spiral 22 and the portion thereof connected to segment 26 with the entryway 24 being adapted to admit a conductor into passageway 23.

Referring now to FIG. 3, the greatest portion of inner spiral 20 is of substantially equal radial dimension to define an elongated, generally semicylindrical member 21. A relatively short segment 28 of enlarged radial dimensions is integrally connected to member 21 through arcuate, angularly disposed shoulder 25. In this fashion inner spiral 20 is defined by two generally semicylindrical, longitudinally aligned, integral portions of differing radial dimensions.

Outer spiral 22 has an elongated midportion 27 of continuous, generally tubular shape. An integral, axially aligned flared female connection end 12 is provided on the right-hand end of midportion 27 as shown in FIG. 3. This comprises a series of three integrally interconnected, longitudinally aligned and communicating frustoconical sections 29, 31 and 33. Section 29 defines the extreme right-hand portion of cover 10 with the widest diameter thereof forming a leading edge opening into the interior of the cover. Sections 31 and 33 are connected at their respective circular edges of greatest diameter and cooperatively serve to interconnect section 29 with midportion 27. Moreover, sections 31 and 33 present an annular, radially enlarged, inwardly facing, recess-defining portion 32 spaced inwardly from the extreme edge of cover 10 which is important for purposes to be made clear hereinafter. Portion 32 is defined by integral, generally annular sloping sidewalls 34 and 36 which are interconnected to form a circular apex 38 of enlarged radial dimensions with respect to midportion 27.

At the distal end of midportion 27, a male connection end 14 is provided. This comprises a series of two longitudinally aligned, integrally connected frustoconical sections 35 and 37. Section 35 is positioned at the extreme left-hand end of cover 10 as depicted in FIG. 3 and is disposed such that the circular edge thereof of least diameter defines the extreme leading edge of the cover. Section 37 is positioned inwardly from section 35 and serves to interconnect the latter with midportion 27. In this regard, sections 35 and 37 are interconnected along their respective edge of greatest diameter, thereby presenting an annular, radially expanded collar 40 defined by generally annular, sloping sidewalls 42 and 44.

As further depicted in FIG. 2, the enlarged, generally semicircular segment 28 of spiral 20 is adjacent the above-described female connection end 12 of outer spiral 22. Similarly the male connection end 14 of the latter is adjacent the end of elongated member 21 removed from segment 28.

The use of the conductor covers of the present invention can be readily explained with reference to FIG. 4. In this instance an elongated, energized conductor 46 is covered by a pair of identically configured, connected spiral conductor covers 10a and 10b. By virtue of the generally semicylindrical, radially enlarged segment 28a of inner spiral 20a, it is possible to telescopically interengage the latter with the extreme end of relatively unenlarged portion 21b. In this fashion, a double thickness of insulative material surrounds conductor 46 at the point of interconnection of the two covers 10a and 10b. Moreover, because of the fact that both the inner and outer spirals of each cover are substantially equal in length, there are no gaps or cutaway portions which serve to lessen the insulative efficiency of the unit. It should also be pointed out that the amount of overlap is very important in some instances as the insulative efficiency of such a junction could be less than that of the sheet material should the amount of overlap be below a given critical value. Therefore, in order to guard against such an eventuality, the amount of overlap is generally greater than that required simply for a secure mechanical interconnection between the covers.

In order to facilitate the insertion of the extreme end of unenlarged spiral portion 21b into the enlarged segment 28a, the latter is angularly cut as at 48 so that the leading edge thereof does not interfere with the abovedescribed telescopic insertion. Further, tab portions 16a and 16b are trimmed from the respective ends 12a and 14b of the separate covers in order to prevent interference therebetween during the interconnection of the covers. As depicted in FIG. 4, the respective tabs are preferably cut back to an extent such that interference therebetween is precluded.

Still referring to FIG. 4, the female connection end 12a of cover 10a telescopically receives male connection end 14b to provide a secure, frictional connection between the structurally distinct covers 10a and 10b. In this regard, the annular, upstanding collar 40b extends into the interior of cover 10a beyond the first frustoconical segment 29a into mating alignment with the annular recess-defining portion 32a of female connection end 12a, the latter cooperatively formed by a pair of communicating frustoconical segments and as described. Hence, the frustoconical segments 35b and 37b of male end 14b are thus received within the correspondingly configured frustoconical segments of female end 12a. As can be appreciated, this provides a desirable snap-fit between the adjacent covers 10 so that a secure connection is maintained therebetween without the necessity of employing separate external connection collars or the like.

In preferred embodiments, the adjacent inner and outer spirals of the cover 10 are configured as described and arranged such that reception of the unenlarged portion 21b of inner spiral 20b within radially enlarged portion 28a and the interlocking of collar 40b with recess-defining portion 32a can be simultaneously accomplished. In practice, this is effected by first positioning the unconnected covers 10a and 10b adjacent one another on line 46 with the respective male and female ends thereof in proximal, aligned relationship. The separate covers are subsequently moved together in an axial direction to complete the aligned, snap-fit connection shown in FIG. 4.

When it is desired to install a cover 10 in insulative relationship to an elongated conductor, the following procedure is employed. The worker first positions cover 10 so that entryway 24 of the latter is proximal to the conductor to be covered. Cover 10 is then positioned by means of the elongated, insulated handle 18 by shifting the conductor along the arcuate path 23 defined by adjacent, spaced spirals. Such positioning is continued until the conductor seats within the concave face of the innermost spiral at a position shown by the numeral 50 (see FIG. 2). When this is accomplished, the generally semicylindrical inner spiral 20 is in partial covering or wrapping relationship to the generally centrally disposed conductor, with the remainder of the device being suspended thereabout in spaced relationship therefrom. In this manner, two spaced layers of insulative material substantially circumscribe the conductor to insulate the latter, with the air between the two layers providing additional insulative effect.

In another preferred embodiment of the invention, the outwardly extending, elongated, generally radial tab portion 16 integral with outer spiral 22 is formed by folding back a portion of the extreme edge of the continuous sheet upon itself, thereby presenting a tab of double thickness along the length of cover 10. In conventional prior art spiral conductors, a separate phenolic strip or other insulative material has normally been connected to such a tab member in order to provide the requisite strength.

When it is desired to protect a conductor segment supported by a pin insulator or the like, the following has been found to give especially good results. By virtue of the fact that it has now been found advantageous to provide conductor covers which are not trimmed at the ends thereof, it is necessary to employ accessory means to cover the conductor segments proximal to the pin insulator supports. In order to accomplish this, a separate housing is provided that is adapted to interconnect with a pair of opposed, longitudinally aligned conductor covers disposed adjacent the insulator on the conductor.

As shown in FIG. 5, a conductor 46 has a segment 52 thereof which is supported by a conventional pin-type insulator 54 by means of line ties 56. Positioned in covering relationship to segment 52 and insulator 54 is housing 58 which is composed of relatively thin insulative material, and preferably of material identical to that used for the conductor covers 10 of the present invention. Housing 58 is generally arch-shaped in cross section and is dimensioned to cover the above-described apparatus in a spaced relationship therefrom. The distal ends of housing 58 are of constricted radial dimension as shown at 60, and are configured to interlock with collars 40 of the respective conductor covers 10 to provide a snap-fit connection therebetween without the necessity for separate connection.

In installation procedures, the separate conductor covers 10 are first installed on line 46 and with their respective male connection portions adjacent insulator 54. Housing 58 is then snapped over the ends 14 and into locking interengagement with the respective collars 40 thereof to provide the requisite insulation along the entire length of the conductor.

In a similar manner, a stretch of conductor 70 supported by a conventional post-type insulator 72 can be protected (see FIGS. 6 and 7). For this purpose a unitary, generally T-shaped cover 74 composed of flexible synthetic resinous insulative material is employed in conjunction with a pair of spaced, axially aligned spiral conductor covers 10 of the class described.

In particular, cover 74 includes a hollow depending segment 76 and a hollow transversely extending cross-segment 78 communicating therewith. The distal ends 80 of cross-segment 78 are configured to present a female connection end for the reception of male ends 14 of the spiral covers 10. As can be seen from a study of FIG. 7, the respective female ends 80 are similar to female ends 12 of the spiral covers 10 described previously in that they are adapted to receive the male ends 14 of separate covers 10 and provide a frictional, snap-fit connection therebetween.

Unitary cover 74 is defined by separate abutting flexible sections 82 and 84 (FIG. 6) which are connected along the top of cross-segment 78 to form a continuous member. During installation procedures, the cover 74 is preferably handled by means of conventional hot line tools and is first positioned above the insulator in proximal relationship thereto. The cover is then pushed downwardly which in turn causes the respective identical sections 82 and 84 to move relatively outwardly to "open" the cover and facilitate operative placement thereof. When the cover is positioned about insulator 72, the sections 82 and 84 are again in the proximal abutting relationship shown in FIG. 6 to effect the insulative protection required. For this purpose each of the sections 82 and 84 is provided with apertures 86 in the depending segment 76 thereof to facilitate adjustment of cover 74 into its final operative position by means of hot line tools. Following placement of cover 74, separate spiral covers 10 can be moved along line 70 in order that the male ends 14 thereof achieve a snap-fit connection within respective female connection ends 80.

The insulative function of cover 74 is further enhanced by provision of expanded portions therein serving to increase the spacing between energized line 70 and the cover itself. For example, cover 74 is provided with a dome-shaped expansion 86 along the top of cross-segment 78 in conjunction with separate, generally rectangular expansions 87 in each section 82 and 84 along the length of segment 78. Additionally, an elongated expansion 88 is provided in sections 82 and 84 along the length of depending segment 76 for a similar purpose.

It is to be understood that cover 74 can be employed in situations where the post-type insulator is vertically or horizontally aligned, or angularly disposed with respect to the supporting utility pole. With a horizontal or angularly disposed insulator, it is generally necessary to employ spiral covers 10 which have the tab portions 16 trimmed back from their male ends 14 as depicted to preclude interference between the tabs and female connection ends 80 of cover 74. When cover 74 is utilized on a vertically mounted post insulator, however, such difficulties are not encountered because the leading portions of tabs 16 of the separate covers 10 can be inserted within the respective spaces 90 provided along the bottom of female connection ends 80 and defined by the proximal abutting edges of movable sections 82 and 84.

Claims

Having thus dscribed the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A removable protective device for use in insulating an elongated, energized conductor and comprising:

an elongated, continuous sheet of relatively thin electrically insulative material shaped to present a spiral-like cross section with a series of connected, arcuate, spiral-like convolutions each spaced from an adjacent convolution a distance at least equal to the diameter of said conductor to provide an arcuate passageway for the conductor during installation of the device, the latter including:

an arcuate outer wall portion of configuration to substantially circumscribe the section of said conductor to be received therein, and

an arcuate inner wall portion having an inner concave face dimensioned to at least partially wrap about the conductor to provide insulation for the latter and to suspend the device from the conductor, said inner wall portion being spaced from the outer, longitudinally extending edge of the outer wall a distance to provide a conductor entryway communicating with said conductor passageway,

the opposed ends of said inner and outer wall portions being shaped to present respective male and female connection ends respectively for complemental interfitting of at least a pair of said devices in aligned end-to-end relationship with the male ends of each device being telescopically received in adjacent female ends of the proximal device,

said inner wall portion including smooth generally semicylindrical segments on the opposed male and female ends thereof, the semicylindrical segment of said female end being complemental with and of greater radial dimensions than the corresponding semicylindrical segment on said male end,

said outer wall portion including generally frustoconical shoulder-defining segments on the opposed male and female ends thereof, the shoulder-defining segment of said female end being complemental with and of greater radial dimensions than the corresponding shoulder-defining segment on said male end.

2. The protective device of claim 1 wherein the leading edge of said radially enlarged end of said inner wall portion is angularly cut to facilitate insertion therewithin of the male end of an adjacent protective device.

3. The protective device of claim 1 wherein the generally frustoconical shoulder-defining segment on the female end of said outer wall portion comprises:

a first frustoconical section disposed at the extreme end of the device with the generally circular edge thereof of greatest diameter defining the leading edge of said female end;

a second frustoconical section communicating with said first section, said first and second sections being interconnected along the respective generally circular edges thereof of least diameter; and

a third frustoconical section communicating with said second section and connecting the latter to the remainder of said outer wall portion, said second and third sections being connected along the respective generally circular edges thereof of greatest diameter, whereby, the second and third frustoconical sections cooperatively define an annular, radially enlarged, inwardly facing, recess defining portion spaced inwardly from the leading edge of the female end.

4. The protective device of claim 3 wherein the generally frustoconical shoulder-defining segment on the male end of said outer wall portion comprises:

a fourth frustoconical section positioned at the extreme male end of the device with the generally circular edge thereof of least diameter defining the leading edge of said male end; and

a fifth frustoconical section communicating with said fourth section and interconnecting the latter with the remainder of said outer wall portion, said fourth and fifth sections being connected along the respective generally circular edges thereof of greatest diameter, whereby, the fourth and fifth frustoconical sections cooperatively define an annular, radially expanded collar with the apex thereof spaced inwardly from the leading edge of said male end.