US3271009A - Method of and apparatus for stringing extra heavy duty electric power conductors - Google Patents

Description

p 1966 R. H. WRIGHT ETAL 3,271,009

METHOD OF AND APPARATUS FOR STRINGING EXTRA HEAVY DUTY ELECTRIC POWER CONDUCTORS Filed Jan 4 1965 2 Sheets-Sheet 1 N oE w. Z 3 8 8 5 9 n M @v mm mm 8. mm 3 on a 9 3 ow no 9 w w w V H a ROBERT H. WRIGHT EDWARD J. MOULTON AT TORNEYS p 966 R. H. WRIGHT ETAL 3,271.009

METHOD OF AND APPARATUS FOR STRINGING EXTRA HEAVY DUTY ELECTRIC POWER CONDUCTORS Filed Jan. 4, 1965 2 Sheets-Sheet 2 K FIG.3d 35 ii mvmrons ROBERT H. WRIGHT 55 25 BY EDWARD .1. MOULTON United States Patent 3,271,009 METHOD OF AND APPARATUS FOR STRINGING EXTRA HEAVY DUTY ELECTRIC POWER CONDUCTORS Robert H. Wright, 6366 Cobbler Rock Lane, and Edward J. Moulton, 2223 Castle Hill Lane, both of Salt Lake City, Utah Filed Jan. 4, 1965, Ser. No. 422,960 7 Claims. (Cl. 254-1343) This invention relates to methods and apparatus for stringing large diameter, heavy duty, electric power conductors over supporting towers by use of puller machines and tensioner machines.

Little difficulty is experienced when the conductor is of a size in the range up to one inch in diameter, but when, for example, a two inch, or larger, conductor must be strung, considerable difficulty is encountered. Thus, with a relatively small diameter and, consequently, light weight conductor, a continuous length can be easily handled over great distances and a very long length can be wound on a single roll. Moreover, when it becomes necessary to go from roll to roll in the extending of the line over many miles, the adjoining ends of the conductor lengths can be easily spliced or otherwise interconnected, as for example, with a flexible sock-type connector, without making for difficulty in the passing of the resulting conductor over the blocks used on the towers during the stringing operation.

This is not so, however, with a relatively large diameter and, consequently, heavy conductor. Such conductor, e.g. the two inch conductor previously mentioned, cannot be provided rolled in great length, nor can the necessarily shorter lengths be spliced or otherwise interconnected in a manner which permits normal use of conventional tower blocks for the stringing operation. Furthermore, an exceedingly difficult situation is presented when the electric power line must cross such obstacles as wide rivers and canyons. In such instances, it is not feasible to lay out the necessary lengths, end-toend, for joinder into an extended length and to then elevate such extended length by crane or the like onto the supporting insulators of the towers, all without resort to the usual stringing operation, but, rather, it becomes highly desirable to have some way of utilizing a stringing operation which closely conforms to conventional practice as applied to conductors of lesser diameter and weight.

The conventional stringing operation cannot be used for these relatively large diameter and heavy conductors not only because of their excessive bulk and weight, but also because the individual conductor lengths must be interconnected by jumpers which require the use of rigid coupling devices having protruding ears for attachment of the jumpers. Furthermore, conventional stringing methods, it used to place heavy conductors, result in undesirable stresses being applied to the towers.

In placing a heavy conductor a lightweight pulling cnble, extending between the tensioner and puller machines, is first positioned over blocks suspended from the towers. A heavier weight pulling cable is connected to the end of the lightweight pulling cable and is then pulled across by the puller. The conductor, made up of a length of conductor connected to the heavier pulling cable, and additional lengths of conductor coupled at ground level as they come off the tensioner machine, is stretched across the towers between the machines.

In those instances where an existing conductor is to be replaced it may be used as a pulling cable for the con ductor to be installed.

If the couplings between the lengths of conductor are "ice dragged over blocks suspended from the towers they are damaged and the blocks may also be damaged such that they will soar the conductor subsequently pulled over them.

It is, therefore, a principle object of this invention to provide a method and apparatus whereby a relatively large diameter and heavy conductor can be pulled into position on supporting towers by puller and tensioner machines without damage to the conductors, to the couplings between individual conductor lengths, or to the tower blocks.

In achieving this object we utilize a plurality of suspended blocks, some of which are adapted to be moved with respect to others such that the couplings can be raised to clear each of the blocks over which the conductor must pass.

There is shown in the accompanying drawings specific embodiments of the invention representing what are presently regarded as the best modes of carrying out the generic concepts in actual practice. From the detailed description of these presently preferred forms of the invention, other more specific objects and features will become apparent.

In the drawings:

FIG. 1 is a schematic representation of electric conductors, one being positioned to span a river in accordance with the process, and utilizing the apparatus of the invention, and another in position to be permanently suspended from spaced suspension towers;

FIG. 2, a vertical section taken on the line 2-2 of FIG. 1;

FIG. 3, an enlarged fragmentary side elevation taken within the line 3-3 of FIG. 1;

FIG. 3a, a view like that of FIG. 3, but showing the bridling apparatus illustrated in FIG. 3 in the position it assumes as a coupling moves over a block;

FIG. 3b, a view like FIG. 3a with the bridling apparatus in another position;

FIG. 30, a view like FIG. 3b;

FIG. 3d, another view like FIG. 3b;

FIG. 4, a vertical section taken on the line 4-4 of FIG. 3

FIG. 5, an enlarged fragmentary side elevation taken within the line 5-5 of FIG. 1:

FIG. 6, a similar view taken within the line 6-6 of FIG. 1; and

FIG. 7, an alternative construction of the bridling assembly of the invention.

Referring now to the drawings:

The method of the invention is best explained in conjunction with the preferred embodiments of apparatus shown, but, as will become apparent, the method could also be practiced with other apparatus.

In FIG. 1 a plurality of conductor support towers are shown at 10, 11, and 12. Towers 10 and 12 are located on opposite banks 14 and 15, respectively, of a river 16 and tower 11 rises from the river midway between towers 10 and 12. Although the towers are here illustrated as being of truss construction it should be apparent that poles or other types of support structure would serve as well in many instances.

A tensioner machine 17 is positioned on bank 14 a spaced distance from tower 10, and in alignment with the line of towers. An A-frame 18 is securely anchored between tower 10 and tensioner 17 so that conductors can be either permanently or temporarily connected thereto.

A puller machine 18 is positioned on the opposite bank 15, a spaced distance from tower 12, and in alignment with the towers and the tensioner machine. The tensioner and puller machines can be of any satisfactory readily available type, and per se, they form no part of the invention. As is customary, reels 17a, having conductor lengths coiled therearound are carried by the tensioner machine, and brakes on the tensioner machine allow the tension on the conductor payed out from the reels and around bull-wheels 17b to be set as desired.

Another A-frame is securely anchored between post 12 and the puller machine, in alignment with the towers and the tensioner machine.

The conductor is pulled from the reels 17:: on the tensioner machine by power driven reels 18a of puller machine 18. As illustrated in FIG. 1, one conductor 22, made up of coupled conductor lengths 23 has already been suspended from towers 10, 11, and 12, and its ends have been secured to A-frames 18 and 20.

An installation line 24, made up of coupled conductor lengths 25, is shown as it is being pulled from reel 170 by puller machine 18 with a small diameter, lightweight pulling cable 26 and a heavier pulling cable 27. The small pulling cable is light enough that it can be placed across blocks suspended from the towers with a helicoptor and can then be wrapped around a reel 18a on the puller machine. As the small pulling cable is wrapped around the reel 18a, the heavier pulling cable is pulled across to be taken up on the reel, while pulling the conductor lengths into position.

In their final position the conductor lengths are positioned such that their coupling means are at the towers 10, 11, and 12.

In pulling installation line 24 into position, the couplings between pulling cable 27 and the first conductor lengths 25, and between the other conductor lengths are pulled across blocks suspended from arms on the towers 10, 11, and 12. Since the end fittings 28 for the couplings are elongate to tightly grip the line to which they are affixed, with the end fittings between pulling cables and between pulling cable 27 and the first conductor length connected by pins, and plates 30, the weight of the suspended line tends to bend and otherwise damage the fittings if they are dragged across the blocks. Furthermore, if they are dragged across the blocks, the elongate end fittings and connecting plates damage the pulleys, so that conductor lengths subsequently pulled across them are scarred. The damaged fittings and the scarred line cause coronas along the conductor, with resultant power losses and interference with radio signals, etc. in the vicinity, as well as a weakened conductor.

The sag in the conductor is set to design specifications after it is in place by the use of hydraulic cylinders and turnbuckles connected between conductor lengths. To allow easy placement of the cylinders, choker cables 31 having end fittings 31a, and plates 32, are pin connected between the ends of the conductor lengths. The com ductor lengths are selected to terminate adjacent the towers when the conductor is in position, thus making it possible to replace the choker cables with the hydraulic cylinders, and to then replace the hydraulic cylinders with turnbuckles and to provide jumper conductor lengths around the turnbuckles, all while working from the relative safety of the riser portion of the tower.

A special bridling apparatus is preferably used to place the transmission line without damaging the connector fittings and suspended blocks. This apparatus includes a frame 33 having spaced side rails 34 and 35, FIG. 4, and axle rods 36 and 37 adjacent the ends of the side rails. The rods serve as axles for grooved end blocks 38 and 39, respectively. The frame is suspended in a level position from the arm of the transmission line support tower that is to finally support the line and adjacent the vertical riser portion of the tower, by cablcs 40 of equal length that are respectively connected to one end of a side rail and to a ring 41 positioned above the center point of the frame. A hook 42, interconnects truss member 43 of the tower arm and ring 41.

An upper block 44 is suspended at short distance below ring 41, but above frame 33, by a cable 45 that is con- Cit nected through a hanger 46 to a rod 47 that forms an axle for the block.

A center block 48 is journallcd about an axle shaft 49 and the axle is carried by the lower end of a keyhole shaped bracket 50. A cable 51 is fixed at the upper end of bracket 50 and passes upwardly over block 44 and down to a winch 52, FIG. 1. Cable 51, bracket 50 and block 48 are all freely vertically movable between side rails 34 and 35 of frame 33.

In use, as shown in FIG. 1, a bridling apparatus is suspended from each arm that is to support a conductor and the pulling cables are pulled over each of the end blocks, passing freely through the enlarged upper portion of each keyhole bracket 50. The puller machine is operated to wind the small pulling cable on to a drum and to pull the other pulling cable, or cables, and finally the conductor into position between the tensioner and puller machines. As each coupling between the pulling cables, pulling cable and conductor, or conductor and choker cable, that is subject to damage, approaches the first end block of the bridling assembly (FIG. 3a) the puller machine is stopped and cable 51 is wound upon winch 52 to raise center block 48 between side rails 34 and 35. As the center block is raised the installation line passing through the enlarged opening of keyhole bracket 50, FIG. 4, is guided by the curved configuration of shoulders 55 into the groove of the block. Continued raising of the center block will raise the line until the coupling can clear the end block. The puller machine is again operated and the coupling is moved above the end block without damage to the coupling or the block, FIG. 3b. The center block is then lowered to a point beneath the level of the end blocks and the coupling is moved above and beyond the center block, at which time the puller machine is again stopped and the center block is raised, FIG. 30, to raise the installation line. The puller machine is started and the coupling is passed over the last end block, again without damage to the coupling or to the block.

If the couplings interconnecting lengths of conductor and the choke cable are being passed over the blocks, as illustrated, the center block must be raised once again to allow the trailing coupling to pass over the last end block. Obviously, in such an arrangement the length of the choker cable must be selected to allow the pair of conplings to simultaneously pass above the end blocks when the center block is raised. This is best illustrated in FIGS. 3b and 3c. The same procedure is followed at each bridling assembly for each coupling, until the conductor lengths are positioned to make up a conductor such as is shown at 22 in FIG. 1.

In FIG. 7 we show an alternative construction of a bridling apparatus. As in the one previously disclosed embodiment, a frame 56, having journalled end blocks 57 and 58 is provided, and cables 59 are connected to the four corners of the frame so that frame can be horizontally suspended from a ring 60 carried by arm truss member 45. A double upper block 61 is journalled about an axle 62 of a hanger 63 that is suspended by cable 64 from the ring 60. Cable 65 fixed to upstanding bracket 66 at the end of frame 56 at which end block 57 is journalled passes over the block 61 and is attached to a reel of a winch. Another cable 69 is fixed to upstanding bracket 70 at the end of the frame adjacent block 58, and it also passes over block 61 before being attached to the reel of the winch.

When the construction of FIG. 7 is used, and a coupling approaches end block 57, cable 69 is wound in by the winch to raise the end of the frame to which it is attached, thus raising block 58 and the installation line passing thereover. At the same time, cable 65 is payed out to lower the other end of the frame, thus moving block 57 down, away from the installation line. This raises block 58 and lowers block 57 to the dotted line position of FIG. 7, such that subsequent operation of the puller machine will move the coupling safely past block 57.

When the coupling can clear block 57 the puller machine is operated to continue movement of the conductor until the coupling is past block 57. Then the puller machine is stopped and the winch is reversed to wind up cable 69 while paying out cable 65 until the blocks are positioned such that the coupling can safely clear block 58.

Once the conductor has been positioned with conductor lengths extending from the tensioner machine to tower 10, from tower to tower 11, from tower 11 to tower 12, and from tower 12 to the puller machine, the ends of the conductor lengths at the tensioner machine 17 and puller machine 18 are respectively fixed to A-frames 18 and 20.

The functions of the tensioner and puller machines are complete at this point and all that remains is to adjust the sag in the conductor between towers to design specification, and to permanently suspend the conductor from the tower arms.

In adjusting the sag in the conductor between towers, a cable 75, attached to the tower arm is connected to each choker cable 31, and the associated bridling assembly is then removed. A pair of hydraulic cylinders 76, FIGS. 1 and 5, are positioned each with its housing pivotally connected to the plate 32 on the end of fitting 31a of one of the conductor lengths by pins 78 passing through flanges 79 on the housing and holes 80 in the plate, and with its rod pivotally connected by pins 81 to a hole 82 in a center plate 83.

A support cable 84 is suspended from arm 43 and is connected to a central hole in plate 83 by a pin 85, and cable 75 is removed. Hydraulic fluid is supplied to and exhausted from the cylinders through hoses 86, shown fragmentarily in FIG. 5, as required to move the ends of the conductor lengths toward or away from each other until the approximate desired sag is obtained. A turnbuckle 87 is then connected to each plate 32 and to a hole 89 in center plate 83, the hydraulic cylinders are removed, and the turnbuckles are adjusted to more precisely set the sag to design specification. Jumper conductor lengths 90, FIG. 6, are then connected between ears 91 on the end fittings 28 to complete the electrical circuit through the conductor. Spacers 92 are used to hold the jumper con ductor lengths separated. A hoist (not shown) is used to swing the conductor and support cable 84 away from the vertical rising portion of the tower until a string of insulators 93, suspended from the arm 43 can be attached to the central hole in center plate 83. Support cable 84 is removed and installation is complete. The same operation is followed at each tower for each conductor suspended.

The methods and apparatus disclosed herein, while particularly advantageous for moving couplings past support blocks, can also be advantageously used to move stitf 1ocalized splice sections of the conductor, and/or dumbbell type dampeners that may be afiixed to the conductor, past the blocks. These dampeners may be used, for example on extremely long spans to reduce vibration of the conductor.

Whereas there are here illustrated and specifically described certain preferred methods and apparatus which are presently regarded as the best modes of carrying out the invention, it should be understood that various changes may be made and other procedures and constructions adopted without departing from the inventive subject matter particularly pointed out and claimed herebelow.

We claim:

1. A method of stringing an electric power conductor for a power line, said conductor having at least one portion along its length unsuited for passing over the usual supporting block on a tower or other elevated structure, comprising the steps of passing an end of said conductor over such a block and pulling thereon until the said portion reaches the block;

transferring the weight of the conductor to a different support at a location adjacent to the block; separating the conductor and the block sufliciently for all) said portion of the conductor to by-pass the block upon continued pulling of the conductor;

pulling the conductor until said portion thereof bypasses the block;

and transferring the weight of the conductor back to the block for continued stringing.

2. A method of stringing an electric power conductor for a power line comprising the steps of using a puller machine to pull a pulling cable across blocks suspended from a plurality of suspension towers positioned between the puller and tensioner machines;

coupling to the end of the pulling cable at the tensioner machine, a conductor made up of coupled conductor lengths connected to the tensioner machine, said pulling cable and said conductor making up an installation line;

pulling said installation line until the said conductor spans the distance between each of the towers and extends between the puller machine and the tensioning machine; during the said pulling operation, as each coupling approaches each block suspended from the tower, changing the relative elevations of the block and said conductor adjacent thereto, whereby continued pulling will cause the coupling to pass above the block without coming in contact therewith; and

repositioning the block and said conductor following each of said changing of the relative elevations, whereby said conductor rests on each block after each coupling has passed thereby.

3. The method of claim 1, further including the step of adjusting the tension in the conductor until the sag in the conductor between suspension towers is at design specifications.

4. Apparatus for stringing an electric power conductor for a power line, which conductor has at least one portion along its length unsuited for passing over the usual supporting block of a tower, comprising at least one block adapted to be connected to a support tower to carry the weight of the electric power conductor passed thereover; alternate conductor support means positioned adjacent said block; and means for changing the relative elevations of the conductor engaging surfaces of the block and the alternate conductor support means, whereby the weight of the conductor can be transferred to said alternate conductor support and the portion of the conductor can be pulled past the block without engagement therewith, and whereby the weight of the conductor can be transferred back to the block and the cable can be pulled past the alternate conductor support without engagement therewith.

5. Apparatus for stringing an electric power conductor for a power conductor for a power line, comprising a frame adapted to be suspended from a conductor support tower; a pair of grooved end blocks; means mounting one of said blocks at one end of the frame and means mounting the other of said blocks at the other end of the frame whereby the grooves of the blocks are in alignment and a conductor can pass over the blocks in the grooves thereof; and means for selectively raising the conductor to allow couplings therein to pass above each of the grooved blocks.

6. Apparatus according to claim 5, wherein the means for selectively raising the conductor includes a grooved center block positioned between the pair of end blocks and in alignment therewith; and means adapted to raise the groove of the center block into engagement with the conductor and above the elevation of the grooves of the end blocks, whereby the couplings can pass over the end pulleys without coming in contact therewith, and to lower the center block such that its groove is below the elevation of the grooves of the pair of end blocks, whereby the couplings can pass over said center block without coming in contact therewith.

7. Apparatus according to claim 5, wherein the means for selectively raising the conductor includes, a block adapted to be suspended from the conductor support tower; and a pair of cables, one of said cables being fixed to one end of said frame and passing over said block in one direction, and the other of said cables being fixed to the other end of said frame and passing over the block in the opposite direction, whereby pulling on the free end of either of said cables will cause the end block at the end of the frame to which the pulled cable is attached to be raised and the block at the other end to be lowered, so that the couplings can pass over the lowered block without coming in contact therewith.

No references cited.

WILLIAM FELDMAN, Primary Examiner.

O. M. SIMPSON, Assistant Examiner.

Claims (1)

1. A METHOD OF STRINGING AN ELECTRIC POWER CONDUCTOR FOR A POWER LINE, SAID CONDUCTOR HAVING AT LEAST ONE PORTION ALONG ITS LENGTH UNSUITED FOR PASSING OVER THE USUAL SUPPORTING BLOCK ON A TOWER OR OTHER ELEVATED STRUCTURE, COMPRISING THE STEPS OF PASSING AND END OF SAID CONDUTOR OVER SUCH A BLOCK AND PULLING THEREON UNTIL THE SAID PORTION REACHES THE BLOCK; TRANSFERRING THE WEIGHT OF THE CONDUCTOR TO A DIFFERENT SUPPORT AT A LOCATION ADJACENT TO THE BLOCK; SEPARATING THE CONDUCTOR AND THE BLCOK SUFFICIENTLY FOR SAID PORTION OF THE CONDUCTOR TO BY-PASS THE BLOCK UPON CONTINUED PULLING OF THE CONDUCTOR;

Images