US3235228A - Conductor stringing tool assembly - Google Patents

Description

Feb. 15, 1966 E. LINDSEY CONDUCTOR STRINGING TOOL ASSEMBLY INVENTOR. A, 5 4/4/0557 Filed Jan. 10, 1964 United States Patent 3,235,228 CONDUCTOR STRINGING TOOL ASSEMBLY L. E. Lindsey, 222 Vista, Pasadena, Calif. Filed Jan. 10, 1964, Ser. No. 336,898 21 Claims. (Cl. 254-1343) This invention relates to means for installing conductors along power lines and more particularly to an improved stringing tool assembly designed to be supported quickly and detachably in a temporary manner on the outer end of pole-type insulators and employed to facilitate pulling a conductor into position along the pole line and for then transferring the conductor into the insulator clamp before thestringing tool is detached for reuse.

The present invention has particular utility in connection with insulators known as pole mounted, i.e. an insulator projecting generally horizontally from the side of the pole and having conductor clamping means at its outer terminal end. The installation of conductors along a pole line utilizing this type of insulator has presented troublesome problems and several designs have been proposed in attempts to resolve the problems but each has serious shortcomings and disadvantages obviated by the present invention. t is desirable that the stringing tool include means for quickly, easily and safely attaching the same to the insulator while leaving the conductor clamp unobstructed and free, to receive the conductor. The stringing tool must not place undue strain on the insulator itself and should provide adequate provision for guiding the conductor around both inside and outside bends lengthwise of the pole line. Inside bends are those in which the conductor bends inwardly toward the pole and place the insulator under compression, whereas ourside bends are those in which the conductor bends away from the pole thereby tending to place the insulator under tension.

It is therefore a primary purpose of the present invention to provide a rugged, simple,.lightweight-unitary stringing tool assembly designed to be rigidly but detachably secured to the terminal end of a pole-type insulator without need for tools.

Another object of the invention is to provide a unitary stringing tool assembly that can be easily secured to the terminal of a pole-type insulator by snap-action means designed to lock the tool positively in place thereon. Another object of the invention is the provision of a stringing tool assembly utilizing a sheave rotating about sheave rotating in a plane transversely of the insulator closely beside its outer end and tiltable latera ly to a position readily transferring the conductor into the insulator clamping means.

Another object of the invention is the provision of a stringing tool assembly utilizing a sheave rotating about an axis generally aligned with the insulator and having means for connecting the same to the outer end of the insulator with the plane of the sheave adjustable to tilt in either direction from the vertical thereby to accommodate both inside and outside bends lengthwise of the pole line.

Another object of the invention is the provision of a stringing tool assembly provided with means for temporarily securing the same to the upper end of a pole-type insulator and having hand-grip means thereon for convenience in tilting the sheave inwardly toward the insulator and in position to discharge the conductor into the seating groove of the insulator clamping means.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate.

Referring now to the drawing in which a preferred embodiment of the invention is illustrated:

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FIGURE 1 is a side elevational view, partly in section, showing a preferred embodiment of the invention stringing tool assembly mounted on the outer end ot a pole-type insulator;

FlGURE 2 is a fragmentary sectional view taken along the broken line 2-2 on FIGURE, 1 and showing eonstructional details; and

FIGURE 3 is a fragmentary elevational' view, partly in section, showing the cable fully assembled to the insulator and the stringing tool detached therefrom.

Referring more particularly initially to FIGURE 3, thereis shown a typical pole ill of a cross country power line having a conventional side-mounted: Pole-line insulator 11 secured to its side by means of through bolts 12;. The hardware at the outer terminal end of'insulator 11 includes a unitary cap 13 and L-shaped bracket 14 having a conductor clamping unit 15 held pivotally seated therein by a pivot screw 16). It; will be understood that the clamping unit 15 includes a conductor seating or saddle member 18 provided with aligned sockets opening through its opposite lateral sides one of which seats over a'boss l9 axially of end cap 13 and the other of which receives the reduced cylindrical end of cap screw 16. A complementally shaped upper clamp half 21 is secured in place astride the conductor by means of cap screws 22. Additionally and importantly, it is pointed out that bracket 14 includes a vertically disposed reinforcing web 23 provided with an opening 24 to seat the latch plunger ofthe stringing tool as will be described in detail presently.

Referring now more particularly to FIGURES 1 and 2, a preferred embodiment of the stringing tool constituting the present invention will be described. The stringing.

tooldesignated generally 30, is a self-contained unitary device one of which is required for each insulator of the pole line along which it is desired to install a power conductor, such as the multiple strand conductor 25. Stringing tool 30 is preferably made of a suitable high strength, light weight alloy such as a high strength aluminum alloy. The principal components are cast and have the configurationillustrated in FIGURES l and 2. Thus the tool in.- cludes a hollow main body 32 providedat its outer end with aligned trunnions held in assembled position by set screws 34 and having a purpose to be explained in greater detail presently. The portion of main body 32 between trunnions 33 is hollowedout and shaped to fit loosely about the outer end of insulator bracket 14 and particu-. larly the head of cap screw 16. In other words, it will be understood that the right hand end of main body 32 may 'be viewed as a socket having a close telescopic fit over cap screw 16 and the shorter vertical leg of L-shaped bracket 14.

The left hand end of main body 32 is bifurcated to permit its assembly astride the vertically disposed web portion 23 of bracket 14. One side wall of the bifurcated portion of main body 32 is provided with a well 31 r-eci procably seating a locking latchv or plunger 38 urged to its extended position by compression spring 39. operating handle or pin 40- projects laterally from plunger 38 and downwardly through an elongated slot inthe side wall of well 37. This slot allows handle 40 to be shifted to and fro as necessary to move latching plunger 33 into and out of latching position in opening z iof insulator bracket 14. From the foregoing and particularly FIGURE 2,.it will be understood that when plunger 38 is in theposition there shown, stringing tool 30 is held firmly assembled in its operating position on insulator 11.

The other principal sub-assembly of tool .30 comprises a Y-shaped sheave support member 45 having aligned openings through its Y-arms 46 j ournalled on trunnions 33, 33. These trunnions hold Y-mem-ber 45 in assembled position for limited arcuate movement in a vertical plane about the axis of the trunnions. Stem 48 of the Y-memher serves as the support for an anti-friction bearing 49 on which the grooved sheave 51B is mounted. The bearing and sheave is held assembled to Y-stem 48 by a radial bracket member 53 held in assembled position by keeper pin 54. Bracket 53 extends along the outer face of sheave 50 and has an arcuate outer end overlying and spaced outwardly from the sheave groove. A pivot pin 56 secured in place crosswise of the outer end of bracket 53 supports a safety dog 58 having an integral bail shaped operating handle 59 straddling the outer end of the bracket. A torsion spring 60 mounted loosely about pivot pin 56 strongly biases safety dog 58 to the full-line position shown in FIGURE 1 with the bight portion of operating handle 59 lying against bracket 53. It will be apparent that when the safety dog is in this position conductor cable 25 is held captive within the sheave and cannot be dispensed therefrom until safety dog 58 is pivoted inwardly to the dot and dash open position shown in FIG. 1.

There remains to be described the latching means for locking sheave-supporting means 45 in a desired operating position and the associated means for selectively varying the angular-position between this latch means and the sheave proper. These important features will now be described by reference to FIGURES 1 and 2.

Normally and so long as the cable is being strung along straight sections of the power line, it is desirable that the sheave be supported in a vertical position transversely of the end of insulator 11 as shown in full lines in FIGURE 1. However, if a pole is located at a bend in the power line then it is desirable that the sheave be tilted, either inwardly or outwardly with respect to its normal vertical position, depending on whether the conductor will act to place the insulator under compression or under tension. If an inside bend is involved then it is desired that the top of the sheave be tilted outwardly away from the insulator whereas if an outside bend is involved tending to place the insulator in tension then the top of the sheave should be tilted inwardly toward the insulator by an appropriate angle.

- To accommodate these objectives, one of the Y-arms 46 is provided with an extension to which a threaded stud 65 is held firmly secured by set screw 66. The outer end of stud 65 projects laterally through an arcuate slot 68 formed in a latch sector 69 pivotally supported on the adjacent one of trunnions 33. It will therefore be apparent that sector 69 can be pivoted through a short are centered on trunnion 33 provided locking nut 72 on stud 65 is loose. However, if this nut is tightened then the sector is held tightly clamped against arm 46 with the result that sector 69 is constrained to pivot bodily with Y-member 45 and sheave 50. Arcuate slot 68 is sufiiciently long to permit adjustment of the sheave through an angle of approximately 90 degrees or 45 degrees to either side of its vertical position.

The means for latching sheave 50 and sector 69 immovably in a desired position includes a latch bolt 75 spring-pressed toward latching position by a compression spring 76 mounted in a well of boss 77 forming part of main body 32. The outer end of latch 75 is further slidably supported in an opening passing through a lug 79. When latch 75 is extended, it engages behind detent 80 carried by latch sector 69 in the manner best shown in FIGURE 1. The opposite side of detent 80 then abuts a stop 81 projecting outwardly from the side of main body 32. Latch 75 is provided with an operating handle'85 conveniently positioned to be grasped by an operator when it is desired to unlatch the sheave for free pivotal movement counterclockwise about trunnions 33, it being impossible for the sheave to pivot counterclockwise by reason of engagement of detent 80 with stop 81.

The operation of the described stringing tool will be quite apparent from the foregoing detailed description of its construction and general purposes. It will be unno or minimum effort by the lineman.

derstood that the unitary assemblies 30 are readily attached to the terminal end of an insulator by seating the socketed end of main body 32 over the outer end of the insulator bracket 14 while holding latch plunger 38 (FIG. 3) retracted. As soon as this plunger is in alignment with opening 24 of bracket 14, plunger 38 is released permitting its spring 39 to extend the plunger through the opening thereby positively locking the stringing tool to the insulator. Either prior to or after mounting tool 30 on the insulator, nut 72 may be loosened and the sheave tilted clockwise or counterclockwise through an appropriate angle depending on whether the particular pole is located at an inside or an outside curve lengthwise of the power line. Once the proper angular adjustment has been made, in accordance with the principles outlined above, nut 72 is firmly tightened.

The next step is to thread a leader or other tension line through the successive sheaves with the far end of the line attached to the conductor to be installed. Thereafter the tension line is pulled through the various sheaves by suitable power winches thereby gradually advancing the main conductor through the sheave and lengthwise of the power line.

As soon as the conductor has been drawn into position the lineman climbs the pole and grasps the operating handle 85 of latch and retracts and rotates handle to latch the plunger open behind boss 86. He then can grasp safety dog handle 59 and pull this handle toward him over the top of bracket 53 with the same hand used to unlatch plunger '75. This opens the safety dog to the dotted line position shown in FIGURE 1 following which further pulling force applied to handle 59 tilts the entire sheave sub-unit about trunnions 33 until the sheave is in the conductor dumping position shown in FIGURE 1. At this point, the downwardly inclined side wall of the sheave groove acts to discharge conductor 25 automatically into clamping socket by gravity action and with The operator then releases handle 59, allowing the sheave to return to its former position and then places clamping cap 21 in position over the firmly seated conductor and tightens clamping cap screws 22.

Before leaving the pole the lineman grasps assembly 30 in one hand and handle 40 of latch 13 in the other. As soon as the latter latch is retracted, the lineman can lift tool 30 from the outer end of the insulator and lower it to the ground for re-use in the same manner described above to install further lengths of the power cable.

It is pointed out that the herein illustrated and described line-dumping sheave is highly advantageous and operates smoothly and with a minimum expenditure of energy to transfer a flexible line, conductor, cable or the like from the sheave directly onto a permanent support therefor. This operation is performed quickly without need for tools of any kind and by the manual etfort of a single hand of a lineman while standing on the pole and using his other hand to safeguard his ovm safety or for purposes other than dumping the contents of the sheave.

While the particular conductor stringing tool assembly herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiment of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A stringing tool for installing power conductors between pole-mounted insulators of the type having a conductor clamp and bracket assembly rigidly secured to the outer end thereof, said stringing tool having a main body provided with means for detachably supporting the same temporarily on said bracket assembly, means rotatably supporting a sheave on said main body to one side of said conductor clamp and in convenient position for transferring a conductor from said sheave into said clamp and leaving said stringing tool free for detachment from said bracket assembly, means movably interconnecting said main body and said sheave means, means for releasably locking said sheave in a predetermined plane of operation during installation of a conductor and including manual means for releasing said sheave for movement in a direction to facilitate transfer of a conductor from said sheave into said conductor clamp.

2. A conductor stringing tool as defined in claim 1 characterized in that said means for releasably locking saidsheave in a predetermined plane includes means for supporting said sheave selectively in any one of a plurality of different operating planes while running a conductor along a pole line and around both inside and outside bends. A

3. A conductor stringing tool as defined in claim 1 characterized in that said sheave means includes a frame and axle unit for said sheave, said frame embracing a portion of the groove extending about the periphery of the sheave and including a combined safety guard and manipulating handle, and means normally holding said safety guard in position to prevent sidewise loss of a conductor from the sheave groove until and unless said safety guard is forcibly moved to a release position.

, 4. A stringing tool assembly designed to be temporarily but detachably supported beneath and closely opposite the conductor clamp bracket means of an insulator of the type projecting outwardly from the side of a power line pole or the like, said tool assembly having a main body having first mounting means formed to seat axially over the outer end of said insulator bracket means and second means offset laterally from the axis of said clamp bracket means including fast-action manually actuatable means for rigidly holding said main body assembled to said bracket means, sheave-mounting frame means movably supported on said main body having a sheave rotatably supported therein for rotation in a plane extending crosswise of the axis of said insulator and in close proximity to the conductor clamp of said bracket means.

5. A stringing tool assembly as defined in claim 4 characterized in that said manually actuatable means for holding said main body rigidly assembled to said bracket means includes manually operable spring-biased lock means having an end positioned to enter a juxaposed opening formed in said insulator bracket means to lock said stringing tool assembly to said conductor clamp bracket means.

6. A stringing tool assembly as defined in claim 4 characterized in the provision of manually operable means cooperating with said main body and with said sheave-mounting frame means to hold these two components selectively in different positions with said sheave differently inclined with respect to a horizontal plane through the axis of the insulator on which said stringing tool assembly is mounted.

7. A stringing tool assembly for use in installing a power conductor between generally horizontally projecting pole-type insulators of a power line, said stringing tool assembly having an elongated main body having a socket in one end to receive and seat over the outer end of a conductor supporting bracket means carried on the outer end of the insulator, the opposite end of said main body having yoke means straddling the lower portion of said bracket means, latch pin means carried crosswise of said yoke and engageable with said bracket means to hold said main body temporarily assembled thereon, sheave mounting means movably secured to said main body with said sheave lying in a plane extending crosswise of and closely adjacent the outer end of said bracket means and in position for the convenient transfer of a conductor from support in the sheave to a clamping posi- 6 tion overlying said bracket means and out of contact with said stringing tool assembly.

8. A stringing tool assembly as defined in claim 7 characterized in that said sheave mounting means is held assembled to said main body by pivot means having its axis extending horizontally crosswise of said main body at the end thereof remote from the dielectric of an insulator on which said assembly is mounted, and means for locking said sheave mounting means selectively in different angular positions with said sheave inelined to either side of its normal vertical plane of rotation.

9. A stringing tool assembly as defined in claim 7 characterized in that said sheave mounting means includes an upright rigid stationary bracket on the remote face of said sheave from the insulator on which said assembly is mounted, said rigid bracket partially embracing the entrance to the sheave groove, an L-shaped safety dog pivotally supported in the upper end portion of said rigid bracket and having spring means normally biasing said safety dog to a closed position for blocking a conductor from escape laterally over one edge of saidshe'ave.

10. A stringing tool assembly as defined in claim 9 characterized in that said safety dog includes operating handle means shaped and disposed to lie closely against said rigid bracket when said safety dog .isclosed and being pivotable to a convenient manipulating position for said sheave mounting means when said handle is moved to open said safety dog;

11. A stringing tool assembly adapted to be latched temporarily to the conductor supporting bracket on the outer end of a non-vertically supported insulator, said assembly comprising sheave means havinga mounting yoke extending axially from one end of a shaft for said sheave, a main body member having socket means at one end seatable over the outer end of said conductor supporting bracket and provided with means for temporarily clamping said body member thereto, and pivot means holding said mounting yoke and a sheave thereon assembled to said main body for arcuate movement between a conductor stringing position and a conductor transfer position wherein the conductor present in said sheave is transferred onto said conductor supporting bracket in readiness to be clamped to said insulator.

12. A conductor stringing tool assembly adapted to be snapped onto and from the terminal end of an insulator designed to extend generally horizontally from a support therefor, said assembly having a sheave rotatably supported on frame means, clamping means carried by said frame means contoured to interfit with portions of the insulator terminal end and including snap-action means for holding said assembly detachably assembled to said terminal end without interfering with clamping a conductor to said terminal end, and releasable means selectively holding said sheave in one of a plurality of desired operating planes while a conductor is being pulled into position for transfer into clamping position on said terminal end.

13. A unitary cable stringing tool comprising a Y- shaped member having a sheave journalled on the stem thereof, the ends of said Y -arms having aligned openings therethrough, a mounting bracket for said stringing tool having a hollow main body adapted to be telescoped over the terminal end of an insulator, aligned trunnion means at one end of said main body extending through and providing a pivot support for the openings in the outer ends of said Y-arms, latch means carried by the other end of said main body for latching said stringing tool to the terminal end of an insulator, and latch means interconnecting said Y-shaped member and said main body operable to lock said sheave and its supporting Y-member releasably against pivotal movement about the axes of said trunnion means.

14. A. stringing tool as defined in claim 13 characterized in the provision of adjustable means for varying the angular position of said Y-member relative to said main body existing when locked in its latched position.

15. A stringing tool as defined in claim 13 characterized in the provision of stop means effective to prevent pivotal movement of said sheave except in a predetermined direction to dump a cable seated in the sheave groove laterally therefrom and toward the end of said main body remote from said sheave.

16. A stringing tool as defined in claim 13 characterized in the provision of bracket means secured to the terminal end portion of said Y-stem and keyed thereto to hold said sheave assembled thereon, said bracket means extending radially along one face of said sheave and having an arcuate end overlying and spaced outwardly from the periphery of said sheave, safety dog means pivoted to the outer end of said bracket means and including spring means biasing the same against a stop position wherein said safety dog means and said bracket means cooperate to hold a conductor captive on the sheave, and handle means for said safety dog means.

17. That improvement in means for stringing a conductor between non-vertically mounted pole line insulators which comprises, a unitary stringing tool having means for securing the same to a pole line insulator, sheave means on said tool having a sheave lying in a plane ex tending crosswise and adjacent the outer end of said insulator, and pivot means interconnecting said sheave means to said tool having a pivot axis spaced closely beside the inner face of said sheave and adjacent the sheave axis and the axis of said insulator and permitting said sheave to be tilted sidewise until the groove of said sheave is positioned to discharge a conductor riding therein out of said sheave and onto the terminal end of the insulator on which said stringing tool is supported.

18. That improvement defined in claim 17 characterized in that said stringing tool includes latch means normally positioned to hold said sheave means locked against pivoting movement and being manually releasable to permit the sheave means to tilt toward said insulator to dump a conductor out of said sheave.

19. That improvement in tool means for facilitating stringing a flexible line lengthwise between a plurality of permanent supports for said line, said stringing tool means comprising bracket means rotatably supporting a sheave in a generally upright operating position, means pivotally connected to said bracket means and pivotable about an axis disposed generally parallel to the plane of rotation of said sheave and to one side thereof, said last-named means including means for detachably and temporarily supporting said stringing tool means closely adjacent a permanent support for said flexible line and in such position that sidewise tilting of said sheave about said pivot axis to a generally horizontal position is effective to dump a flexible line out of said sheave and onto the permanent support therefor.

20. That improvement defined in claim 19 characterized in that said stringing tool means includes means normally effective to hold said sheave in a desired upright operating position, and handle means operatively connected to said sheave supporting bracket means for use in manually pivoting the same along With said sheave into line dumping position.

21. That improvement defined in claim 20 characterized in the provision of means on said stringing tool means for normally releasably locking said sheave against pivotal movement about said axis.

References Cited by the Examiner UNITED STATES PATENTS 2,613,256 10/1915 Thomas 254134.3 3,170,673 2/1965 McAuley 254134.3

FOREIGN PATENTS 714,317 8/1954 Great Britain.

WILLIAM FELDMAN, Primary Examiner.

OTHELL M. SIMPSON, Examiner.

Claims (1)

1. A STRINGING TOOL FOR INSTALLING POWER CONDUCTORS BETWEEN POLE-MOUNTED INSULATORS OF THE TYPE HAVING A CONDUCTOR CLAMP AND BRACKET ASSEMBLY RIGIDLY SECURED TO THE OUTER END THEREOF, SAID STRINGING TOOL HAVING A MAIN BODY PROVIDED WITH MEANS FOR DETACHABLY SUPPORTING THE SAME TEMPORARILY ON SAID BRACKET ASSEMBLY, MEANS ROTATABLY SUPPORTING A SHEAVE ON SAID MAIN BODY TO ONE SIDE OF SAID CONDUCTOR CLAMP AND IN CONVENIENT POSITION FOR TRANSFERRING A CONDUCTOR FROM SAID SHEAVE INTO SAID CLAMP AND LEAVING SAID STRINGING TOOL FREE FOR DETACHMENT FROM SAID BRACKET ASSEMBLY, MEANS MOVABLY INTERCONNECTING SAID MAIN BODY AND SAID SHEAVE MEANS, MEANS FOR RELEASABLY LOCKING SAID SHEAVE IN A PREDETERMINED PLANE OF OPERATION DURING INSTALLATION OF A CONDUCTOR AND INCLUDING MANUAL MEANS FOR RELEASING SAID SHEAVE FOR MOVEMENT IN A DIRECTION TO FACILITATE TRANSFER OF A CONDUCTOR FROM SAID SHEAVE INTO SAID CONDUCTOR CLAMP.

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