US3306651A

US3306651A - Apparatus for handling strain insulators

Info

Publication number: US3306651A
Application number: US391588A
Authority: US
Inventors: Ivan S Brown
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-08-24
Filing date: 1964-08-24
Publication date: 1967-02-28
Anticipated expiration: 1984-02-28

Description

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eh & a. s. BROWN APPARATUS FOR HANDLING STRAIN INSULATORS Filed Aug. 24, 1964 INVENTOR. IVAN 8. BROWN United States Patent 3,306,651 APPARATUS FOR HANDLING STRAIN INSULATORS Ivan S. Brown, 115 W. Piedmont Ave., Phoenix, Ariz. 85041 Filed Aug. 24, 1964, Ser. No. 391,588 2 Claims. (Cl. 294-67) This invention relates to the handling of electrical strain insulators. More particularly, it relates to an apparatus and method whereby, in the installation, removal, or repair of electric power lines, suspended from their supports by suspension insulators commonly known as strain insulators, the strain insulators or insulator string may be lifted, pulled or lowered.

Strain insulators of the type of the present invention are usually coupled together to form what is commonly termed the insulator string, the conducting cable being attached to an insulator at one end of the string by means of a strain clamp and the insulator at the other end of the string being attached to the pole tower or other supporting structure.

In the past, the methods and apparatuses employed for pulling, raising, or lowering such described insulator strings have all necessarily required that the linemen involved work in the direct vicinity of the string and the electrical power line. It was necessary that an insulator hoisting member or pick-up be brought into immediate contact with a strain insulator and seated around or attached to the strain insulator to be pulled, for example, and then that this hoisting member exert a pull on the strain insulator, as by attachment of this hoisting member to ropes or cables from a winch at the top of the tower from which the insulator string is suspended.

According to the present invention, a novel hoisting support apparatus and system is provided wherein a minimum number of linemen may efficiently position a hoisting member of novel and efficient type beneath a strain insulator which is part of an insulator string, may securely place it in an optimum position, and raise, pull, or lower said insulator or said string. Further, the apparatus may be secured in position by means of insulated ropes operated from a distance so that the linemen do not need to work in the immediate vicinity of either the insulator string or the electric power line.

As is well known, a typical strain insulator includes a porcelain-like bottom skirt portion which is disc-like in shape and includes a series of annular grooves on its underside. The centermost of these annular grooves is typically positioned directly beneath the main body of the strain insulator. The diameter of this inside groove in the underside of the skirt portion, in the vast majority of strain insulators presently in use and being marketed, is 2% inches. Due to the typical construction of said strain insulators it has been found that this groove which is located directly under the main body portion of a typical strain insulator represents the strongest portion of the underside of the skirt portion of a strain insulator, insofar as ability to withstand compressive forces. The present invention provides as a feature thereof a hoisting member adapted to be positioned immediately adjacent the underside of the skirt portion of a strain insulator, and the hoisting member includes an annular bearing surface which mates with the above-described typical inside groove of a strain insulator when the hoisting member is in place, thus allowing pulling of the strain insulator or string of insulators by compression along the described advantageously-located annular bearing surface. Among the many advantages of the present invention, it has been found experimentally that line crews utilizing the present invention can replace a damaged strain insulator in a 3,306,651 Patented Feb. 28, 1967 string of insulators in less than 20 percent of the time that it takes the same crew utilizing present day devices.

It is a principal object of the present invention to provide an insulator supporting pick-up which is simple in construction and has many fewer parts than those of the prior art.

An additional object and feature of this invention is to provide an insulator supporting pick-up which is easier to work with, takes a smaller crew, is safer to use, and takes less truck space than insulator pick-ups as described in the prior art.

Yet another object and feature of this invention is the provision of an apparatus and method which may be used for handling electrical high line insulators when the electrical high voltage power line is energized as well as when it is de-energized, and for doing so quickly and safely.

An additional object and feature is to provide an apparatus and method of the type described which is equally eflicient for use in handling a single insulator as it is in handling a string of insulators consisting of any number of insulators.

Further and additional novel objects and features of this invention will hereinafter be explained and claimed.

Other objects of the invention will become apparent from the following description of one embodiment of the invention when taken in connection with the drawings which accompany and form a part of this specification.

In the drawings:

FIGURE 1 is a perspective view of a prefered embodiment of the insulator supporting pick-up of the present invention;

FIGURE 2 is a cross section through a typical strain insulator showing the manner in which a portion of the described embodiment of the present invention may be used to support such a strain insulator;

FIGURE 3 is a front view illustrating the manner in which the described insulator supporting pick-up may be used to hold a string of electrical strain insulators.

Generally speaking, the described structural embodiment of the invention comprises a two part insulator pickup device, each said part being arranged to be connected to ropes or cables and moved about and positioned by the movement of said ropes. The first distinct part of the described device comprises a flat member having a straight slot extending from the center of said member to its periphery. In line with said slot, but at the opposite periphery of said flat member, is a rope support adapted to engage a rope for pulling in a direction substantially perpendicular to said flat member. At the periphery of said flat member at the location of the slot and at either side thereof, are a pair of rope support members adapted to be attached to ropes for pulling in a direction in the plane of said flat member and roughly in the direction of the opening of the slot. The center of said flat member is further characterized by the presence of a truncated cone-like protrusion extending upwardly and perpendicularly of said flat member and rising from an annular base portion immediately around the end of said slot situated in the center of said flat member to an annular bearing portion of slightly smaller diameter than that of said base portion and extending in through a slightly greater angular arc.

The second part of the described device comprises a T-shaped fiat member having a rope connection at the base of the T adapted so that an attached rope will pull the T-shaped member in the direction of its longitudinal portion. Said longitudinal portion must be narrower in dimension than the width of the slot of the first part of the invention. Extending from the cross bar of the T,

3 in the direction of the longitudinal member of the T, and parallel to said longitudinal member, are a pair of prong-like protuberances, one at either end of the cross bar member of the T. ,These prong-like protuberances are adapted to fit into and through a pair of holes situated near the periphery of the said first part of the described device on either side of the slot of the said first part.

Referring now particularly to the accompanying drawings, FIGURE l'illustrates the two parts of the apparatus similar tension means (not shown in FIGURE 1) for A pulling the insulator pick-up of the present invention in an upward direction. A straight slot 10 extends from the center of the disc-like center portion to the end of arm 11. Situated on either side of slot 10, at the outward extension of arm 11, are a pair of loops 9. Each 100139 is adapted to be connected to a rope for pulling and positioning the main body A of the insulator pick-up of the present invention, as will be later more fully described. Also, positioned at the endof arm 11 on either side of slot 10, are a pair of holes 8 through the arm 11 and in a direction perpendicular to the plane of said disclike center portion 15. A partial truncated cone 14 extends upward from disc-like center portion 15 around the portion of slot 10 which terminates in the center ofdisclike center portion 15. Cone 14 terminates upwardly in an annular bearing surface 13 which surface is parallel to the plane of disc-like center portion 15.

The second part of the insulator pick-up apparatus of the present invention is denoted in FIGURE 1 as part B thereof and is termed herein the floating support member B. The floating support member B is T-sh-aped and flat and comprises a rectangular base portion 24 from which extends, in a direction perpendicular to said base portion 24, a narrow rectangular portion 25. This narrow rectangular portion 25 should be of a width sufficiently small to enable it to fit into the width of slot 10. At the end of portion 25 is disposed a loop 6 adapted to be attached to a rope for pulling part B. At either end of the rectangular base portion 24 of part B, prongs 7 extend parallel to the narrow rectangular portion 25. Prongs 7 are adapted to fit freely and easily into holes 8 of part A.

In FIGURE 2 is illustrated in detail, cross-section, the glass or porcelain-like portion 1 8 of a strain insulator of typical construction. Illustrated also is a portion of the metallic body portion 21 of the strain insulator of FIGURE 2. Shown in cross-section resting against the ridged bottom of the glass or porcelain-like portion 18 of the strain insulator to be pulled is cone 14. It is noted that the upper annular bearing surface 13 of cone 14 is shaped so as to fit and bear against the central annular groove 19 (which has, typically, a diameter of 2% inches) of the ridged bottom of the glass portion 18 of the strain insulator of FIGURE 2. Bearing surface 13 is convex in contour and has about a y -inch radius. It is seen that, when the cone portion 14 of the main body A of the insulator pick-up of the present invention is in proper position beneath a strain insulator, said main body A makes its only contact with the insulator along the upper annular bearing surface 13 of cone 14 bearing along the central annular groove 19 of the ridged bottom of the glass portion 18.

The area of the annular groove 19 is the strongest part of the insulator and the placement of cone 14 in the position shown in FIGURE 2 enables said cone 14 to bear tioned, of the main body A and 4 13 and groove 19 and its location is very important and is a critical part of the present invention; 'At this location the greatest possible structural strength may be found without destruction or damage to the glass portion of the insulator.

With reference now to FIGURE 3, there is illustrated a group of strain insulators 26 connected with each other in typical string fashion. The insulator pick-up apparatus of the present invention is illustrated mounted in place beneath the upper strain insulator of the illustrated insulator string. And the relative locations when so posithe floating support B, are clearly illustrated. u i

The method and manner in which the illustrated ap= paratus of the present invention is used is below described.

A rope 28 is attached to loop 5 and'ropes 27 are attached to the two loops 9 of themain body A, and by means of manipulation of'theseropes 27 and 28, part A is guided between a pair of straininsul'ator'sfin the direction of slot 10 so that the insulator'string is situated in slot 10.

The width of slot 10 must be made sufficiently large so that the upper part of the insulator (situated next below the one to be pulled) will not impede the positioning of part A. The opening in the annular bearing surface 13, however, need not be as wide as slot 10 since it need not be passed by the next-below insulator and since the maxi mum safely-obtainable bearing surface is desirable for optimum application of force. Thus, the partial truncated core 14 is a preferred structure for optimum placement and geometry of surface 13 on part A.

Part A is then further positioned until bearing surface '13 of cone 14 comes incontact with groove 19 of the strain insulator directly above part A, thereby forming the desired bearing surface. It should be mentioned at this point, that to secure proper visual alignment, disc like center portion 15 ofpart A is made circular in ap proximately the same size, butlarger than, the glass portion 18 of the strain insulators and cone 14 is, of course, centered in said disc-like portion 15. Therefore, by securing proper visual alignment of the periphery of disclike portion 15 and the periphery of the glass portion 18 of the desired strain insulator, consistently proper placement of the desired bearing surfaces may be obtained.

' Other visual marker means may be used for this purpose,

although the means described is preferred. '-When the main body part A of the described insulator? pick-.up of the present invention has bee-n'properly positioned as shown inIFIGURE 2, the floating support partB is positioned by means of a rope'23 attached at loop 6 thereof. I

Part B is positioned upwardly so that prongs '7. become seated in holes8 and so that part B provides support for pulling its end of part A. At this point tension or pulling a in describing the present embodiment tension, compression or movement in a horizontal direction or in directions between horizontal and vertical are obviously just as readily accomplished by use of the present invention. And although theterm up,wa'rd-hasbeen used herein to avoid confusion of relative directions and for simplicity of description,the insulator string may be, and very frequently is, pulled in direction more nearly horizontal.

It is readily seen that linemen using the apparatus and method of the present invention need haveno close contact with electrical hot wires at all. In the prior art it has been necessary that there be a certain amount of hand operation in the immediate vicinity of hot wires, but

with maximum safe force in an upward direction against I the strain'insulator. This bearing surface between surface the use of positioning by means of ropes or similar tension means which the present invention provides makes the insulator pick-up of the present invention muchsafer than any prior apparatus or method. v

It is understood that the above teachings are illustrative in nature. Many modifications, alternatives, and variations of the present invention will be apparent to those skilled in the art from the teachings herein, and it is intended that all such modifications, alternatives, and variations fall within the scope of the present invention, limited only by the appended claims.

What is claimed is:

1. A strain insulator pickup device of the character described, comprising: a first main support member including a disc-like central body portion, a pair of arms extending oppositely outwardly therefrom, the first arm of said pair including at its peripheral end mechanical attachment means adapted to be attached to tension means for positioning said first main support member and the second arm of said pair including a straight slot extending from the peripheral end of said second arm to the center of said disc-like central body portion, said second arm having at its peripheral end a pair of mechanical attachment means, one on either side of said straight slot, adapted to be attached to tension means for positioning said first main support member, second arm including a pair of holes, one on either side of said straight slot at its peripheral end, said holes being perpendicular to the plane of said disc-like central body portion, and a truncated cone-like protuberance extending perpendicularly from the plane of said disc-like central body portion and from the center of said disc-like central body portion, said protuberance having an annular bearing surface at its end adapted to bear against the center underside of the skirt portion of a strain insulator; and a second floating support member including a rectangular base portion having parallel prong-like protuberances extending one from either end thereof and adapted to mate with said pair of holes on either side of said slot of said first main support member and a perpendicular portion extending perpendicular to said base portion and from the center portion of said base portion and in the same direction as said prong-like protuberances, said perpendicular portion including mechanical attachment means adapted to be attached to tension means for positioning said second floating support member.

2. A strain insulator pickup device for pulling or positioning a string of insulators attached to an electric power cable, wherein said string of insulators includes strain insulators of the type having a porcelain-like skirt portion whose underside contains an annular groove located directly beneath the main body portion of said strain insulator, said strain insulator pick-up device including: a hoisting member including an annular bearing surface adapted to mate with said annular groove; said hoisting member being adapted to be positioned so that said annular bearing surface may be brought into bearing contact with said annular groove; said hoisting member including observable marker means for accurate visual positioning of said annular bearing surface against said annular groove; said observable marker means comprising a disc-like portion of said hoisting member whose plane is parallel to the plane of said annular bearing surface and whose diameter is slightly larger than the diameter of said skirt portion of said strain insulator.

References Cited by the Examiner UNITED STATES PATENTS 2,700,201 1/1955 Bannister 294102 3,052,003 9/1962 Eyler 24-123 3,202,450 8/1965 Servis 29491 GEMLD M. FORLENZA, Primary Examiner. G. F. ABRAHAM, Assistant Examiner.