US3659034A

US3659034A - Self-damping bundle conductor spacer

Info

Publication number: US3659034A
Application number: US75804A
Authority: US
Inventors: Charles B Rawlins; Fred R Collins
Original assignee: Aluminum Company of America
Current assignee: Howmet Aerospace Inc
Priority date: 1970-09-28
Filing date: 1970-09-28
Publication date: 1972-04-25
Anticipated expiration: 1989-04-25

Abstract

Self-damping bundle conductor spacer for maintaining apart suspended lengths of adjacently extending electrical conductors, including at least two opposed conductor clamps for clamping respectively a portion of the girth of a corresponding electrical conductor, each of the clamps being interconnected in spaced relation with the next adjacent clamp by a corresponding substantially transversely extending elongated helical spacer spring having a hollow axial bore, and a damping bundle of substantially parallel discrete flexible metal strands occupying substantially the cross section of the axial bore of a corresponding spring with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the spring along at least a portion of the extent of the axial bore in dependence upon tension and compression forces acting on the assembly.

Description

United States Patent Rawlins et al.

[54] SELF-DAMPING BUNDLE CONDUCTOR SPACER [72] Inventors: Charles B. Rawlins; Fred R. Collins, both of Massena, NY.

[73] Assignee: Aluminum Company of America, Pittsburgh, Pa.

[22] Filed: Sept. 28, 1970 [21] Appl.No.: 75,804

3,121,770 2/1964 Dallye 1 74/42 FOREIGN PATENTS OR APPLICATIONS 534,274 9/1931 Germany ..l5/200 [45] Apr. 25, 1972 OTHER PUBLICATIONS Chance advertisement entitled Research Tranquilizes Bundle Conductors," Electrical World, Vol. 161, No. 12, March 23,1964, page 153.

Primary Examiner-Laramie E. Askin Attorney-Robert E. lsner and Peter J. Franco [57] ABSTRACT Self-damping bundle conductor spacer for maintaining apart suspended lengths of adjacently extending electrical conductors, including at least two opposed conductor clamps for clamping respectively a portion ofthe girth of a corresponding electrical conductor, each of the clamps being interconnected in spaced relation with the next adjacent clamp by a corresponding substantially transversely extending elongated helical spacer spring having a hollow axial bore, and a damping bundle of substantially parallel discrete flexible metal strands occupying substantially the cross section of the axial bore ofa corresponding spring with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the spring along at least a portion of the extent ofthe axial bore in dependence upon tension and compression forces acting on the assembly.

15 Claims. 6 Drawing Figures PATENTEmPRzs m2 3. 659,034

INVENTORS CHARLES B. RAWLiNS BY FRED R. COLLINS ATTORNEY SELF-DAMPING BUNDLE CONDUCTOR SPACER This invention relates to a self-damping bundle conductor spacer for maintaining relatively fixed separation between suspended lengths of adjacently extending electrical conductors, and more particularly to such a spacer in the form of an assembly of at least two opposed conductor clamps, each interconnected in spaced relation with the next adjacent clamp by a corresponding helical spacer spring having a hollow axial bore stuffed with a damping bundle of parallel discrete flexible metal strands in frictionally stiff condition.

Generally, bundle conductor spacers are used to maintain relatively fixed spatial separation between suspended lengths of adjacently extending overhead electrical stranded cables or conductors, or more specifically subconductors in bundles comprising the phases of certain high voltage transmission lines. Under particular conditions, attributable to either wind action or corona discharge or other fault on the line, these subconductors oscillate at low frequency and at amplitudes of several inches or more, causing periodic variation in, and departure from the desired, subconductor separation. When such motions are severe enough, they result in mechanical damage, eg through fatigue, to the hardware by which the subconductors or conductors are suspended, for example from high tension towers.

These oscillations may be reduced in severity by incorporating damping characteristics in the bundle conductor spacers operatively positioned between parallel suspended lengths of the conductor lines. Damping may be introduced into the system by making the bundle conductor spacers compliant to the concomitant oscillating forces caused by the subconductor or conductor motions, with the compliance incorporating a damping component.

Various self-damping bundle conductor spacer constructions are known. These generally include a pair of opposed conductor clamps interconnected in spaced relation by an interposed flexibly mounted tube or helical spring having an axial bore through which a damping element extends from one such clamp to the other. Three or four such clamps may be employed for larger bundles, i.e. where three or four conductors or subconductors are to be maintained in spaced relation, a common spring interconnecting a given clamp with the next adjacent clamp to form a spacer assembly having a corresponding triangular or rectangular configuration, with the damping elements extending through the springs between adjacent clamps.

Conventional damping elements include axially resilient corrugated strips, wires, stranded rope or cable, flexible envelopes containing flowable damping media, and the like, which are usually positioned within the hollow bore of the helical spring. However, spacer assemblies embodying these conventional damping elements are often difficult or expensive to manufacture, limited in inherent damping characteristics, subject to early failure, constructionally intricate or cumbersome, or otherwise impractical in use.

These bundle conductor spacers during use are subjected to compression and tension forces on the tubes or springs as the subconductors or conductors in the bundle oscillate toward and away from one another. While these tubes or springs were designed to withstand such forces, the damping elements heretofore employed have not always been able to minimize the effect of the oscillating forces and achieve early return to a static condition. Moreover, when excess compression forces act on the interconnecting tube or spring, there is a severe bending or bowing of the tube or spring which tends to distort the damping element, followed by a stretching of these parts under the tension forces of the rebounding conductors, resulting in early fatigue and failure of the system.

By employing a curved axis helical spring as the separator between the conductor clamps, oscillations due to wind, fault current, e.g. short-circuits, corona discharge, etc., are more readily accommodated since the spacer is compliant to the compressive forces and the conductors come together at the location of the spacer. On the other hand, a spring spacer with a straight axis encounters the full compressive force of two power transmitting conductors or subconductors slamming together, e.g. when there is a fault on the line, and on rebound of the conductors away from each other, which likewise takes place under substantial force, the spring is placed under concomitant tension stresses.

Of course, by allowing the conductors of a bundle to come I together at the location of the spacer, as occurs especially with a curved axis helical spring assembly, there is also a more uniform impact along the length of the conductors which tends to reduce the force at which they rebound and separate. Thus, a curved axis spring spacer tends to receive less abuse by conductor movements, e.g. those caused by the action of the wind, ice conditions and faults on the line.

It is an object of the present invention to overcome drawbacks previously encountered and to provide a bundle con ductor spacer assembly having enhanced damping charac teristics, achieving early return to static condition when parallel runs of suspended cables or conductors equipped with such spacer are subjected to oscillating motion.

It is another object of the invention to provide a spacer assembly of the foregoing type which effects early decay of vibratory oscillations regardless of their source of generation.

It is a further object of the invention to provide such a spacer assembly which is simple in construction, relatively inexpensive to fabricate, durable in use, and resistant to premature failure from fatigue.

It is still another object of the invention to provide a bunch or bundle of unstranded substantially parallelly extending, preferably normally arcuate, discrete flexible metal strands, e.g. in the form of substantially uniform diameter round wires of substantially equivalent length having the ends of the strands affixed or bounded together at one common end, such as by a strap or cast metal bond, and having the ends of the wires freely disposed in close adjacency at the other common end, for use as a component of the subject spacer assembly.

It is a still further object to provide a wire bunch or bundlestuffed spring in the form of an elongated open convolution helical spring normally arcuately biased in axial direction in repose and having a hollow axial bore stuffed with a bunch or bundle of unstranded substantially parallelly extending, preferably normally arcuate, discrete flexible metal strands composed of substantially uniform diameter round wires of substantially equivalent length in frictionally stifi condition, for use as a combined component of the subject spacer assembly.

Other and further objects of the invention will become apparent from a study of the within specification and accompanying drawings, in which:

FIG. 1 is a schematic view, partially in section, of a twoclamp bundle conductor spacer assembly according to one embodiment of the invention.

FIG. 2 is a schematic view of a bundle of parallelly extending wires bound together at one common end, according to another embodiment of the invention,

FIG. 3 is a schematic view, partially in section, of a clamp arrangement according to a modification of the invention,

FIG. 4 is a schematic view of a three-clamp bundle conductor spacer assembly according to a further embodiment of the invention, and

FIGS. 5 and 6 are enlarged schematic views illustrating alternate forms of apex clamps in conjunction with the embodiment of FIG. 4.

It has been found, in accordance with the present invention, that a bundle conductor spacer assembly of enhanced selfdamping characteristicsmay now be provided, which contemplates at least two opposed conductor clamps, each interconnected in spaced relation with the next adjacent clamp by a corresponding, preferably normally arcuate, helical spacer spring, at least one corresponding spring having a hollow axial bore stufi'ed with a damping bunch or bundle of parallel dis crete flexible metal strands in frictionally stiff condition.

Generally, such self-damping bundle conductor spacer assembly, which is eminently suitable for maintaining relatively fixed separation between suspended lengths of adjacently extending power transmitting electrical conductors, comprises at least two opposed conductor clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each of such clamps being interconnected in spaced relation with the next adjacent clamp by a corresponding elongated helical spacer spring having a hollow axial bore, and a corresponding damping bundle of substantially parallel discrete flexible metal strands occupying substantially the cross section of the axial bore of at least one such corresponding spring with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the spring along at least a portion of the extent of the axial bore in dependence upon external forces acting on the assembly.

Preferably, the spring is a normally open wound spring having the helical convolutions along at least a portion thereof in open spaced apart relation to each other, and the bundle of strands is composed of substantially uniform diameter round flexible, e.g. galvanized steel, wires outwardly embraced or encompassed by the spring and maintained thereby in frictionally stiff condition.

In particular, the common ends of the strands at one end of the bundle may be affixed to one another, e.g. by a strap or cast metal bond, while the common ends of the strands at the other end of the bundle are freely disposed in close adjacency.

Referring to the drawing, FIG. 1 shows a self-damping twoclamp bundle conductor spacer assembly 1 for maintaining relatively fixed separation between spans or suspended lengths of adjacently, e.g. substantially parallelly, extending conventional electrical conductors or sub-conductors 2. The two opposed conductor clamps 3, preferably of identical construction, and of electrically and aerodynamically suitable smooth configuration, are positioned to clamp respectively a portion of the girth ofa corresponding electrical conductor 2.

Each of the clamps is interconnected in spaced relation with the other by the substantially transversely extending elongated helical spacer spring 4 which is preferably normally arcuately biased in the axial direction of the spring, in repose, and has a hollow axial bore 5. A damping bunch or bundle 6 of substantially parallel, preferably normally arcuate, discrete flexible metal strands 7 occupy substantially the cross section of the axial bore of the spring 4 in frictional surface contact with one another along their common extent, yet strands 7 are relatively slidably displaceable with respect to one another and with respect to the confining or surrounding portions of the spring 4 along at least a portion, and preferably along the entirety, of the extent of the axial bore 5 in dependence upon tension and compression forces acting on the spring through the clamps, e.g. due to a fault on the line, which tend to displace the spring out of the normal, e.g. normally arcuately biased, disposition thereof.

Spring 4 is preferably a normally open wound spring having the helical convolutions along at least a portion thereof, e.g. the center portion, in open spaced apart relation to each other as shown by the interspacings 8 to absorb compression forces more readily. Also, the bundle 6 of strands 7 is preferably composed of substantially uniform diameter round flexible wires, e.g., normally arcuate wires, outwardly embraced by spring 4 and maintained therewithin in frictionally stiff condition.

Clamps 3 each include a distally extending pair of coacting conductor engaging clamp surfaces 9 and 10, respectively, on the appropriate main parts 11 and secondary parts 12 thereof for operatively clamping conductors 2, as well as a corresponding medially extending spring seating collar or projection 13, as the case may be. The ends 14 of spring 4 are operatively connected to clamps 3 at the respective projections 13.

in the embodiment shown in FIG. 1, projections 13 are outwardly tapered from a larger main diameter to a smaller terminal diameter, whereas ends 14 are correspondingly outwardly flared from the smaller main diameter of spring 4 to a larger terminal diameter, consonant with the angle of taper of projections 13, to enable the spring ends to be fixedly, yet preferably removably, seated on the opposing projections. For this purpose, the external correspondingly tapered helical grooves or threads 15 are provided on the outer surfaces of the corresponding projections 13. The ends 14 of spring 4 are merely screwed onto the projections via these threads.

Projections 13 contain respectively the bundle recesses or blind bores 16 substantially coaxially aligned with the axial bore 5 of spring 4, so that conveniently the corresponding ends of the strands 7 extend snugly into the opposing recesses 16 and terminate therewithin a selective distance from the inner ends 17 of the opposing recesses to permit sliding displacement of the strands 7 with respect to one another and with respect to the spring and recesses in dependence upon the forces acting on the spring.

The tapering and flaring connection between each projection and the spring assures continuity of the confining disposition of the bundle in the transition from the axial bore to the corresponding recess of each such projection.

The recesses or blind bores 16 can be formed, if desired, by providing a free bore through the shank portion of the corresponding main clamp part 11 of each of the clamps and closing off the portion thereof adjacent the secondary clamp part 12 thereat by way ofa plug 18 or the like.

It is preferred that the confining diameter of recesses 16 and the axial dimension thereof extending to the inner ends 17 be selected, with regard to the composite cross sectional dimension of the bundle 6, such that slight radial and axial clearance exists between the ends of the bundle 6 and the confines of the opposing recesses into which such ends are inserted. In this way, as the assembly is displaced from its normal disposition. by reason of oscillations or vibrations caused for instance by a fault on the line, relative axial movement or frictional slippage of the individual strands 7 can occur with respect to one another and with respect to the spring 4 and opposing recesses 16 without undue hindrance from the confining walls of the recesses.

Moreover, depending upon the type of forces exerted on the assembly, the bundle 6 can even rotate to a limited degree within one or both recesses 16, possible with concomitant rotational frictional slippage yet without undue hindrance from such confining walls, and rotate in turn within axial bore 5 of spring 4. On the other hand, it is not generally intended that any relative rotation occur between the ends 14 of the spring 4 and the projections 13 of the clamps 3 as this might cause undue twisting of the assembly and/or of the suspended conductors.

The relative axial and/or the relative sliding displacement or slippage between individual portions of strands 7 in contact with one another, as the case may be, advantageously is accompanied by extensive friction which serves in a surprisingly effective manner to dampen the resulting oscillation caused by external vibratory forces exerted on the assembly.

According to a preferred embodiment of the invention the common ends of the strands 7 at one end of the bundle 6, i.e. within one of the opposing recesses 16, are affixed to one another by suitable retaining means 19 while the common ends of the strands at the other or opposite end of the bundle, i.e. within the other of the opposing recesses 16, are freely disposed with respect to one another. The retaining means 19 can be positioned at the very end of the bundle or slightly spaced therefrom since the significant factor is the optional retaining of the individual strands against disruptive positive movement therebetween as opposed to friction-generating relative movement therebetween.

The retaining means 19 can take any suitable form, such as a metal strap tightly wrapped around the composite girth or circumference of the bundle 6, with the strap ends connected fixedly together, preferably under tension, or such as a metal bond, e.g. a zinc bond or solder bond, fixing or fusing the individual strands together thereat.

Naturally, whatever form the retaining means takes, the same will be dimensioned to provide at most a very slight increase in the composite cross section of the bundle 6 so as to avoid undue binding thereof against the interior wall of the particular recess 16 and scoring or marring of such wall. Such scoring or marring would eventually cause excessive wear and perhaps even failure of the system, and in the interim would hinder proper rotational and axial slippage of the bundle necessary to attain the maximum purposes of the invention.

ln this regard, in the case of the use of a strap for the retaining means 19, because of the tight wrapping thereof about the bundle, no undesirable increase in cross sectional dimension should occur. In the same way, the use of a metal bond will not cause difficulties since the bonding takes place substantially between and among the strands of the bundle, more or less within the bundle girth, rather than beyond the periphery of the composite cross section thereof.

It will be realized that even though the bundle 6 in the optional, though preferred, retaining means embodiment forms a composite in which the individual strands 7 cannot execute actual or positive axial displacement with respect to one another, this is not of decisive significance since the crux of the inclusion of a bundle of individual strands in the assembly of the invention is to use the friction caused by slippage between portions of the lengths of individual strands which are in contact with one another, under the conditions of external force applied to the system, to dampen the vibrations or oscillations generated in the system.

Since in the preferred embodiment the strands 7 are disposed in an arcuate configuration in the bundle 6, by reason of the configuration and disposition of the encompassing spring 4, each strand 7 will have a slightly different are of curvature or trajectory from the next. Consequently, as the normal arcuate disposition, or position of repose or static condition, of the spring 4 and the bundle 6 is disturbed, different portions of the strands along the length of the bundle will slip relative to adjacent portions at different rates so as to generate an overall frictional resistance to the vibrations or oscillations to achieve the damping in question.

This function of relative displacement of segments or portions of the individual strands in the bundle is substantially independent of any arrest of actual or positive displacement of individual strands with respect to the remaining strands in the bundle by reason of the presence of retaining means 19, and will even occur where a straight axis spring arrangement is employed. This is true since it is the relative changes in curvature of the strands in the bunch or bundle which lead to the damping action, as discussed more fully hereinafter.

In this regard, inherently, while the spring will absorb tension forces and prevent undue movement apart of the clamps, the selective dimensions and arrangement of the bundle of strands is such that the abutting of the bundle ends against the clamp projections, e.g. against the inner ends of the recesses, under compression forces, will prevent undue movement of the clamps toward one another while the spring will bow to enable the damping action to take place.

Thus, the bundle of strands is generally provided of such a length, in relation to the length of the spring and the longitudinal spacing of the portions of the clamp projections facing the bundle ends, that the bundle ends will inherently limit inward movement of the clamps along the axis of the spring and bundle. Because of the nature of the connection between the spring ends and the clamp projections, with the bundle ends extending directly into the projection recesses as shown in FIG. 1 or with the bundle ends extending indirectly thereinto within the spring ends seated in such recesses as shown below in FIG. 3, the bundle contributes structurally to the radial and axial connection between the spring and clamps.

Each clamp 3, in the particular optional embodiment shown, contains an outer tongue on the main part 11 and a tongue receiving aperture 21 on the secondary part 12 for interlocking main part 11 with secondary part 12 to facilitate the clamping of the appropriate conductor 2 thereat. To accommodate the interlocking of these parts, a slot 22 is defined through each secondary part 12.

Thus, before final tightening of the corresponding threaded locking bolt 23 which extends from the secondary part well or depression 25 to the main part well or depression 24 through threaded apertures in such parts 11 and 12, secondary part 12 may be drawn medially toward the spring area of the assembly to bring the appropriate aperture 21 over and into coacting interlocking engagement with the tongue 20 thereat, with the movement being unhindered in the vicinity of bolt 23 because of the presence of slot 22. Bolt 23 can then be finally tightened to provide a very strong type of clamping engagement for the electrical conductor 2 held thereby.

FIG. 2 shows more clearly as a distinct article the bundle 6 of unstranded substantially parallelly extending normally arcuate discrete flexible metal strands 7. Preferably, strands 7 are composed of substantially uniform diameter round wires, for example galvanized steel wires, of substantially equivalent length. The ends of the strands are affixed together at one common end of the bundle, here via the strap retaining means 19, and those at the other or opposite common end are freely disposed in close adjacency.

Since the wires used to form the strands will ordinarily come from a coil or storing drum, they will already possess an arcuate configuration which advantageously facilitates the making of the arcuate bundle in question.

It will be realized that the term unstranded as used herein connotes the fact that the strands or wires are discrete or separate from one another enabling them to be parallelly disposed in the fonn ofa bundle or bunch. On the other hand, the term stranded is normally used to describe a cable or conductor which is helically laid and connotes the fact that the strands or wires therein are individually intertwined to make them flexible yet self-embracing, i.e. helically disposed with respect to one another rather than discrete, separate or parallel.

Because of the disposition of the bundle or bunch of strands or wires within the axial bore of the helical spring according to the invention, the spring retains the individual strands together and therefore the self-embracing feature of conventional stranded cables is not needed. Since the individual strands are retained in the form of such a bundle a more effective damping action for a given degree of flexibility is achievable than with a stranded cable.

In this connection, stranded cables tend to be stiff because induced curvature causes elongation of the wires of the cable facing the outside of the curve and compression of those wires facing the inside of the curve. Such elongation and compression require considerable energy and consequently make the cable hard to bend. However, large elongations and compressions are circumvented by slipping of the wires. This slipping relieves the stresses that would otherwise occur because each of the helically laid wires in the cable has alternate regions of tension and compression corresponding to the alternate areas thereof which face the outside and inside of the curve in the cable. Slipping in the intermediate regions, in the direction of the wire axis, permits the tension and compression regions to relieve each other to a large degree.

Any such slipping of the wires of a stranded cable, nevertheless, has its drawbacks regarding flexibility, due to the friction and concomitant internal wear which necessarily accompany such slipping and which eventually cause failure of the cable. The friction and wear are usually minimized by using fairly short lengths of lay so that the regions of tension and compression are individually short and deficits and surpluses in wire length which develop during cable bending are small. The amplitudes of slipping in the intermediate regions are correspondingly small as well.

On the other hand, since a frictionally stiff cable effect is intended for achieving the damping action of the assembly of the invention, yet one which avoids the foregoing drawbacks while still providing considerable slipping movement for a given amount of bending, the instant bundle or bunch of parallel discrete flexible metal strands is necessarily utilized. In the unstranded bundle or bunch of strands according to the invention, the length of the lay of the individual wires is taken to its theoretical extreme, i.e. infinity, by making the wires parallel, e.g. in parallel arcs in the case of the normally arcuate bundle preferred embodiment.

With the instant bundle conductor spacer, because of the disposition of the bundle or bunch of unstranded parallel discrete flexible metal strands in frictionally stiff condition within the axial bore of the spring, the flexure thereof caused by the oscillation forces which are generated when the conductors or subconductors oscillate and which tend to push the spacer clamps toward and away from one another, and consequently to bow the spring to a greater or lesser degree of curvature than that of its condition in repose, e.g. its normally arcuate condition, itself produces effectively the damping desired. Since these wires or strands are parallel to one another, or disposed in parallel arcs in the case of the normally arcuate bundle embodiment, slipping occurs between the individual wires and between the wires and the spring in a direction parallel to the axis of the wires, and this slipping is accompanied by inherent intense friction which provides the desired damping action but without undue wear. Hence, the bundle or bunch of strands forming the damping component according to the invention can only be flexed or bended to the accompaniment of damping forces due to friction between the parallel strands or wires, yet advantageously with a much higher damping effect than, and without the undue wear on such wires as would occur with, a corresponding stranded cable form of damping component.

By way of actual comparison, upon substituting lengths of conventional l9-strand galvanized steel damper cable for corresponding lengths of 19-strand parallel discrete galvanized steel wire bundles according to the invention, at the same individual wire diameter, in the axial bore of the helical spring of the instant assembly construction, it was found that the damper cable-containing assemblies yielded damping decrements in the range of only 0.02 to 0.07 whereas the instant unstranded bundle-containing assemblies yielded damping decrements in the much higher range of 0.15 to 0.25 under otherwise the same test conditions. From this it is clear that the unstranded bundle stuffed helical spring arrangement of the invention provides a damping effect which is several times that when using a corresponding stranded cable.

A distinct composite article is therefore advantageously provided according to a particular feature of the invention, comprising an elongated open convolution helical spring normally arcuately biased in axial direction and having a hollow axial bore stuffed with a bundle of unstranded substantially parallelly extending, preferably normally arcuate, discrete flexible metal strands composed of substantially uniform diameter round wires of substantially equivalent length which occupy substantially the cross section of the axial bore in frictionally stiff condition.

The ends of the spring may flare outwardly as shown in FIG. 1, or be substantially the same radius as the remainder of the spring as shown in FIG. 3 to be next described, and the spring may be connected to and seated over or in the clamp projection in any suitable manner.

FIG. 3 shows one end portion of an alternate embodiment of a clamp projection and spring mounting for the bundle conductor spacer assembly, otherwise substantially the same as that shown in FIG. 1. Clamp 30 contains the medially extending spring seating projection 31 which is provided with the bundle recess or blind bore 32 substantially coaxially aligned with the axial bore 33 of the helical spacer spring 34. Recess 32 has substantially the same radius as the outside radius of the corresponding end 35 of the spring 34.

Spring 34 in this embodiment is preferably of the same radius throughout its length, to enable the spring end to be fixedly, yet preferably removably, seated in the projection. For this purpose, the internal helical grooves or threads 36 are provided on the interior wall of recess 32. The end 35 of Spring 34 is merely screwed into the projection via these threads. The axial bore 33 is also correspondingly of the same radius throughout its length.

The corresponding ends of the strands of the bundle 37 extend snugly into the recess 32, i.e. within the axial bore 33 of the spring 34 at the spring end 35, and terminate substantially within the spring a selective distance from the inner end 38 of the recess to permit limited sliding displacement of the strands with respect to one another and with respect to the spring and recess in dependence upon the forces acting on the Spring.

The opposing clamp and corresponding spring end (not shown) are generally identical with the clamp 30 and spring end 35, with the remainder of the spring and the bundle contained therewithin corresponding essentially to the construction shown in FIG. 1.

Naturally, in accordance with the foregoing, in this embodiment also, it is preferred that the confining diameter of the axial bore 33 in the corresponding recess 32 and the axial dimension of the recess to the inner end 38 thereof be selected, with regard to the composite cross sectional dimension of the bundle 37, such that slight radial and axial clearance exists between the ends of the bundle 37 and the confines of the axial bore 33 and the recess 32 thereat.

The bundle 37, similar to the bundle 6 of the embodiment of FIGS. 1 and 2, may or may not be provided with a retaining means such as retaining means 19 or the like.

The embodiments of FIGS. 1 to 3 cover the association of a pair of such clamps and a common such spring having a corresponding such bundle of strands occupying the axial bore thereof, with the clamps being interconnected in opposed spaced relation by the spring to form a substantially linear transversely extending assembly configuration.

On the other hand, the embodiments of FIGS. 4 to 6 cover the association of three such clamps in appropriately apex modified form, and three such springs, each such Spring preferably having a corresponding such bundle of strands occupying the axial bore thereof, and each of the clamps being interconnected in opposed spaced relation with the next adjacent clamp by a corresponding spring to form a substantially triangular transversely extending assembly configuration. The same degree of damping effect is achievable with this constructional arrangement also, due to the presence of the bundle component within the axial bore of the appropriate spring.

In FIG. 4, the self-damping bundle conductor spacer assembly 40 is shown, which is used for maintaining relatively fixed separation between suspended lengths of three adjacently extending electrical conductors. The assembly 40 in effect contains an additional clamp in opposed spaced relation to the pair of clamps contemplated by the embodiments of FIGS. 1 and 3, and two additional springs in corresponding opposed spaced relation to the spring as contemplated by such embodiments of FIGS. 1 and 3. Each spring contains a corresponding damping bundle of the strands in question which occupy substantially the cross section of the axial bore thereof.

More specifically, the substantially equidistantly spaced apex clamps 41, each having a pair of medially extending angular projections 42 extending in angularly outwardly diverging direction, are interconnected in opposed spaced relation with the next adjacent clamp by a corresponding elongated helical spacer spring 43 having the respective spring end 44 thereat operatively seated on the adjacent projection 42, to form a substantially triangular transversely extending assembly configuration. Each spring 43 contains within the axial bore 45 thereof a corresponding bundle 46 of the strands 47. Preferably, all of the spring 43, and the corresponding bundles 46 therewithin, have substantially the same length, and the three corresponding pairs of projections 42 thus define the appropriately dimensioned apexes of the corresponding equilateral triangular configuration.

Springs 43 and bundles 46 containing the strands 47 are generally of the same construction and characteristics as spring 4 and bundle 6 containing the strands 7.

As may be seen more clearly in FIG. 5, each apex clamp 41 contains the distally extending (i.e. with respect to the particular interconnecting spring 43) pair of coacting conductor engaging clamp surfaces 48 and 49 on the appropriate main part 50 and secondary part 51 thereof for operatively clamping the given electrical conductor just as in the embodiments of FIGS. 1 and 3, along with the corresponding pair of medially extending spring seating angular projections 42 on which the spring ends 44 are operatively mounted.

In this instance also, projections 42 are outwardly tapered from a larger main diameter to a smaller terminal diameter while spring ends 44 are correspondingly outwardly flared from the smaller main diameter of the given spring 43 to a larger terminal diameter, consonant with the angle of taper of projections 42, to enable the spring ends to be fixedly, yet preferably removably, seated on the correspondingly opposing projections.

By the provision of the external correspondingly tapered helical grooves or threads 52 on the outer surfaces of the corresponding projections 42, the ends 44 of the springs 43 are merely screwed onto the projections via these threads.

Furthermore, projections 42 contain respectively the bundle recesses or blind bores 53 substantially coaxially aligned with the axial bore 45 of the adjacent spring 43, so that the ends of the strands 47 of the bundle 46 thereat extend snugly into the adjacent recess 53 and terminate therewithin a selective distance from the corresponding inner end thereof to permit sliding displacement of the strands 47 with respect to one another and with respect to the spring and recess in dependence upon the forces acting on the spring. Here also, the tapering and flaring connection between each projection and the corresponding spring thereat assures continuity of the confining disposition of the bundle in the transition from the axial bore to the corresponding recess of each such projection.

It will be realized, of course, that a spring end and projection configuration and connection of the type shown in FIG. 3 can also be used instead of the taper and flare connection shown in FIG. 5, with equally favorable results.

As aforesaid, it is preferred that the confining diameter of recesses 53 and the axial dimension thereof extending to the inner ends 54 be selected, with regard to the composite cross sectional dimension of the bundle 46, such that slight radial and axial clearance exists between the ends of the bundle 46 and the confines of the opposing recesses into which such ends are inserted.

The bundle 46, similar to the bundle 6 of the embodiment of FIGS. 1 and 2, may or may not be provided with a retaining means such as retaining means 19 or the like.

As shown in phantom in FIG. 5, clamps 41 contain the threaded locking bolts 55, which extend from the secondary part well or depression 56 to the main part well or depression 57 through threaded sections in

such parts

50 and 51, to lock the given clamp about the girth of the appropriate electrical conductor to be held thereby.

Parts

50 and 51 of each such clamp 41 are appropriately shaped to permit their unhindered movement into and out of clamping engagement disposition with respect to one another when locking bolts 55 are removed.

FIG. 6 shows an alternate embodiment of a clamp 60 similar to clamp 41 of FIG. and containing the same constructional details for providing a bundle conductor spacer of the type shown in FIG. 4, except for the fact that

semi-main parts

61 and 62 are provided with appropriate coacting conductor engaging clamp surfaces 63 and 64 in place of the

parts

50 and 51.

Parts

61 and 62 are locked together by a pair of threaded locking bolts 65, only one of which is shown, which extend through threaded apertures in such parts from an appropriate well or depression 66 on one such part to a corresponding well or depression 66 on the other such part. The other locking bolt 65 and depressions 66 are positioned on the opposite side of the clamp. The remainder of clamp 60 is the same as clamp 41 of FIG. 5.

Preferably, both the apex clamps 41 and the apex clamps 60 are provided in an electrically and aerodynamically suitable smooth configuration.

It will be realized that a corresponding bundle conductor spacer of the instant type may also be provided with four or more such clamps and springs containing such bundles of strands, if desired, with the only modification being in the concomitantly wider angle of the apex clamps of the types shown in FIGS. 5 and 6 due to necessitated wider angularity of the appropriate clamp projections. Equally favorable self-damping results will be obtained with such higher multiple clamp and spring polygonal assemblies due to the basic constructional concepts provided in terms of the integrated combination of clamps and parallel strand-containing bundle-stuffed springs intended.

In the case of all of the embodiments herein, while it is preferred that the spacer spring and strands in the bundle contained within such spring be normally arcuately biased in axial direction, i.e. in repose, straight axial springs and strands may also be used because of the above-noted basic constructional concept of the present invention. For the same reason, the helical spring need not necessarily be an open wound spring which contains spaces between the helical convolutions, although springs with such spaces are preferred.

As is known, a so-called straight axis spacer spring encounters the total compressive force when the adjacent power transmitting conductors slam together, such as where there is a fault on the line or a violent wind condition or the like, as well as the concomitant tension force when the conductors rebound away from each other. On the other hand, the socalled curved axis or normally arcuate spacer spring preferred herein is compliant to these forces so that the conductors come together at the location of the spacer assembly without the assembly undergoing the full effect of such forces. Moreover, there is a more uniform impact along the length of the conductors which tends to reduce the rebounding force. Hence, the curved axis spacer spring assembly consequently receives less abuse from conductor movements which tend to move the clamps toward and away from each other than does the straight axis spacer spring assembly.

Of course, the particular means used to clamp together the two appropriate clamp parts for clampingly engaging the suspended lengths of adjacent conductors may take any form. Thus, while threaded locking bolts, perhaps used in conjunction with a tongue and aperture connection, have been shown, other such means can be employed for the necessary purpose.

In addition to the foregoing, according to one particularly preferred embodiment of the invention, the assembly generally includes a pair of opposed clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each clamp having a corresponding bundle recess defined therein, an elongated helical spacer spring having a hollow axial bore interconnecting such clamps in spaced relation with the bundle recesses in substantial coaxial alignment with the axial bore, and a damping bundle of substantially parallel discrete flexible metal strands extending through the spring and occupying substantially the cross section of the axial bore and of the bu'ndle recesses with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the axial bore and recesses in dependence upon external forces acting on the assembly.

Moreover, according to another particularly preferred embodiment of the invention, the assembly includes a plurality of at least three opposed clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each clamp having two corresponding bundle recesses defined therein, a corresponding plurality of opposed elongated helical spacer springs, each spring having a hollow axial bore and interconnecting a correspondingly adjacent pair of such clamps in spaced relation with a particular one of the bundle recesses of each of the clamps in the pair in substantial coaxial alignment with the axial bore of such spring, and a corresponding plurality of damping bundles of substantially parallel discrete flexible metal strands, each bundle extending through a corresponding spring and occupying substantially the cross section of the axial bore thereof and of the particular bundle recesses of the clamps in the pair interconnected by such spring with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the corresponding axial bore and bundle recesses in dependence upon external forces acting on the assembly.

As an example of relative dimensions for a two-clamp assembly of the instant type, an 18 inch center line distance between the conductor grooves or clamping surfaces of the two clamps may be employed with a spacer spring of 0.25 inch diameter wire having about a 1% inch outer diameter for the helix, which is stuffed with a bundle of 169 strands in the form of galvanized steel 0.049 inch diameter round wires, the ends of which wires loosely extend about 1% inch into the corresponding bundle recess of the projection of each clamp. Optionally, the ends of the strands or wires at one end of the bundle or bunch can be fixed to each other by dipping approximately an inch at that end of the bundle into molten zinc which thereby provides the bundle retaining means in the form ofa cast metal bond. (see FIGS. 1 and 2).

It will be appreciated that the instant specification and drawings are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention which is to be limited only by the scope of the appended claims.

What is claimed is:

l. Self-damping bundle conductor spacer assembly which comprises at least two opposed conductor clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each of such clamps being interconnected in spaced relation with the next adjacent clamp by a corresponding elongated helical spacer spring having a hollow axial bore, and a corresponding damping bundle of substantially parallel discrete flexible metal strands occupying substantially the cross section of the axial bore of at least one such corresponding spring with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the spring along at least a portion of the extent of the axial bore in dependence upon external forces acting on the assembly.

2. Assembly according to claim 1 wherein such corresponding spring is a substantially transversely extending elongated helical spacer spring normally arcuately biased in the axial direction of the spring in the form of a normally open wound spring having the helical convolutions along at least a portion thereof in open spaced apart relation to each other.

3. Assembly according to claim 1 wherein the corresponding bundle of strands is composed of substantially uniform diameter round flexible wires outwardly embraced by such spring and maintained therewithin in frictionally stiff conditron.

4. Assembly according to claim 1 wherein the adjacent clamps each include a distally extending pair of coacting conductor engaging clamp surfaces and a corresponding medially extending spring seating projection for the corresponding spring, the ends of such spring being operatively connected to the adjacent clamps at the corresponding opposing projections.

5. Assembly according to claim 4 wherein such spring is seated fixedly at the ends thereof over the outer surfaces of the corresponding opposing projections, such projections are provided respectively with bundle recesses substantially coaxially aligned with the axial bore of the corresponding spring, and the corresponding ends of the strands extend snugly into the opposing recesses and terminate within the recesses a selective distance from the inner ends of such recesses to permit limited sliding displacement of the strands with respect to one another and with respect to the spring and recesses in dependence upon the forces acting on the assembly.

6. Assembly according to claim 5 wherein the common ends of the strands within one of the opposing recesses are affixed to one another while the common ends of the strands within the other of the opposing recesses are freely disposed with respect to one another.

7. Assembly according to claim 4 wherein the corresponding opposing projections are provided respectively with bundle recesses substantially coaxially aligned with the axial bore of the corresponding spring, such spring is seated fixedly at the ends thereof in the corresponding opposing recesses, and the corresponding ends of the strands extend snugly into the opposing recesses and terminate within the axial bore of the spring a selective distance from the inner ends of the opposing recesses to permit limited sliding displacement of the strands with respect to one another and with respect to the spring and recesses in dependence upon the forces acting on the assembly.

8. Assembly according to claim 1 wherein a pair of said clamps and a common said spring having a corresponding said bundle of strands occupying the axial bore thereof are provided, the clamps being interconnected in opposed spaced relation by the spring to form a substantially linear transversely extending assembly configuration.

9. Assembly according to claim 1 wherein three said clamps and three said springs are provided, each spring having a corresponding said bundle of strands occupying the axial bore thereof, and each of the clamps being interconnected in opposed spaced relation with the next adjacent clamp by a corresponding spring to form a substantially triangular transversely extending assembly configuration.

l0. Self-damping bundle conductor spacer assembly for maintaining relatively .fixed separation between suspended lengths of adjacently extending electrical conductors, which comprises a pair of opposed conductor clamps, each having a distally extending pair of coacting conductor engaging clamp surfaces for clamping respectively a portion of the girth of a corresponding electrical conductor and a medially extending spring seating projection, a substantially transversely extending elongated helical spacer spring seated at the end portions thereof on the corresponding projections of such clamps to interconnect operatively such clamps in spaced relation, the spring having an axial bore and being normally arcuately biased in the axial direction thereof with at least a portion of the helical convolutions thereof normally in open spaced apart relation to each other, and a damping bundle of substantially parallel and normally arcuate discrete metal strands composed of substantially uniform diameter round flexible wires occupying substantially the cross section of the axial bore of the spring and maintained therewithin in frictionally stiff condition in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the spring along at least a portion of the extent of said axial bore in dependence upon tension and compression forces acting on the spring which tend to displace the spring out of the normally arcuately biased disposition thereof.

11. Assembly according to claim 10 wherein the spring is seated fixedly at the ends thereof over the outer surfaces of the corresponding opposing projections, each projection is provided with a bundle recess substantially coaxially aligned with the axial bore of the spring, and the corresponding ends of the strands extend snugly into the opposing recesses and terminate within the recesses a selective distance from the inner ends of such recesses to permit limited sliding displacement of the strands with respect to one another and with respect to the spring and recesses in dependence upon the forces acting on the spring.

12. Assembly according to claim wherein each projection is provided witha bundle recess substantially coaxially aligned with the axial bore of the spring, such spring is seated fixedly at the ends thereof in the corresponding opposing recesses, and the corresponding ends of the strands extend snugly into the opposing recesses and terminate within the axial bore of the spring a selective distance from the inner ends of the opposing recesses to permit limited sliding displacement of the strands with respect to one another and with respect to the spring and recesses in dependence upon the forces acting on the spring.

13. Assembly according to claim 10 wherein an additional said clamp, in opposed spaced relation to said pair of clamps, and two additional said springs, in corresponding opposed spaced relation to said first mentioned spring, are provided, each spring having a corresponding damping bundle of said strands occupying substantially the cross section of the axial bore thereof, each clamp having a pair of said medially extending projections extending in angularly outwardly diverging direction, and each clamp being interconnected in opposed spaced relation with the next adjacent clamp by a corresponding said spring having the respective spring end thereat operatively seated on the adjacent projection, to form a substantially triangular transversely extending assembly configuration, all of the springs having substantially the same length and the three corresponding pairs of projections defining the apexes of such triangular configuration.

l4. Self-damping bundle conductor spacer assembly which comprises a pair of opposed clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each clamp having a corresponding bundle recess defined therein, an elongated helical spacer spring having a hollow axial bore interconnecting such clamps in spaced relation with the bundle recesses in substantial coaxial alignment with the axial bore, and a damping bundle of substantially parallel discrete flexible metal strands extending through the spring and occupying substantially the cross section of the axial bore and of the bundle recesses with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respects to the confining portions of the axial bore and recesses in dependence upon external forces acting on the assembly.

15. Self-damping bundle conductor spacer assembly which comprises a plurality of at least three opposed clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each clamp having two corresponding bundle recesses defined therein, a corresponding plurality of opposed elongated helical spacer springs, each spring having a hollow axial bore and interconnecting a correspondingly adjacent pair of such clamps in spaced relation with a particular one of the bundle recesses of each of the clamps in the pair in substantial coaxial alignment with the axial bore of such spring, and a corresponding plurality of damping bundles of substantially parallel discrete flexible metal strands, each bundle extending through a corresponding spring and occupying substantially the cross section of the axial bore thereof and of the particular bundle recesses of the clamps in the pair interconnected by such spring with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the corresponding axial bore and bundle recesses in dependence upon external forces acting on the assembly.

Claims

1. Self-damping bundle conductor spacer assembly which comprises at least two opposed conductor clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each of such clamps being interconnected in spaced relation with the next adjacent clamp by a corresponding elongated helical spacer spring having a hollow axial bore, and a corresponding damping bundle of substantially parallel discrete flexible metal strands occupying substantially the cross section of the axial bore of at least one such corresponding spring with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the spring along at least a portion of the extent of the axial bore in dependence upon external forces acting on the assembly.

3. Assembly according to claim 1 wherein the corresponding bundle of strands is composed of substantially uniform diameter round flexible wires outwardly embraced by such spring and maintained therewithin in frictionally stiff condition.

10. Self-damping bundle conductor spacer assembly for maintaining relatively fixed separation between suspended lengths of adjacently extending electrical conductors, which comprises a pair of opposed conductor clamps, each having a distally extending pair of coacting conductor engaging clamp surfaces for clamping respectively a portion of the girth of a corresponding electrical conductor and a medially extending spring seating projection, a substantially transversely extending elongated helical spacer spring seated at the end portions thereof on the corresponding projections of such clamps to interconnect operatively such clamps in spaced relation, the spring having an axial bore and being normally arcuately biased in the axial direction thereof with at least a portion of the helical convolutions thereof normally in open spaced apart relation to each other, and a damping bundle of substantially parallel and normally arcuate discrete metal strands composed of substantially uniform diameter round flexible wires occupying substantially the cross section of the axial bore of the spring and maintained therewithin in frictionally stiff condition in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respect to the confining portions of the spring along at least a portion of the extent of said axial bore in dependence upon tension and compression forces acting on the spring which tend to displace the spring out of the normally arcuately biased disposition thereof.

12. Assembly according to claim 10 wherein each projection is provided with a bundle recess substantially coaxially aligned with the axial bore of the spring, such spring is seated fixedly at the ends thereof in the corresponding opposing recesses, and the corresponding ends of the strands extend snugly into the opposing recesses and terminate within the axial bore of the spring a selective distance from the inner ends of the opposing recesses to permit limited sliding displacement of the strands with respect to one another and with respect to the spring and recesses in dependence upon the forces acting on the spring.

14. Self-damping bundle conductor spacer assembly which comprises a pair of opposed clamps for clamping respectively a portion of the girth of a corresponding suspended length of an electrical conductor, each clamp having a corresponding bundle recess defined therein, an elongated helical spacer spring having a hollow axial bore interconnecting such clamps in spaced relation with the bundle recesses in substantial coaxial alignment with the axial bore, and a damping bundle of substantially parallel discrete flexible metal strands extending through the spring and occupying substantially the cross section of the axial bore and of the bundle recesses with the bundle strands in frictional surface contact with one another along their common extent yet relatively slidably displaceable with respect to one another and with respects to the confining portions of the axial bore and recesses in dependence upon external forces acting on the assembly.