US3711623A

US3711623A - Cable spacers for electrical overhead transmission lines

Info

Publication number: US3711623A
Application number: US00240116A
Authority: US
Inventors: D Schiavone
Original assignee: Gould Inc
Current assignee: Pullman Co
Priority date: 1972-03-31
Filing date: 1972-03-31
Publication date: 1973-01-16
Anticipated expiration: 1990-01-16
Also published as: AR203714A1; GB1392759A; JPS4914992A; FR2178854A1; BR7301606D0; JPS5320313B2; AU4858972A; AU470603B2; CA991287A; FR2178854B1

Abstract

A device for spacing electrical conductors which are used in high voltage transmission lines. The device includes a central hub provided with two or more cavities. A rigid arm articulately extends into each cavity. The arm is provided at one end with a truncated double cone or knob-like structure and the other end is provided with means for holding the conductor. Interposed between the inside walls of the cavity and the knob of the rigid arm, within each cavity, is an elastomeric sleeve having a substantially circumferentially continuous groove arranged adjacent to and alongside of the intersection of the two cones which comprise the knob.

Description

United States Patent [191 Schiavone 1 CABLE SPACERS FOR ELECTRICAL OVERHEAD TRANSMISSION LINES [75] Inventor: Donald James Schiavone, Huron,

Ohio

[73] Assignee: Gould Inc.

[22] Filed: March 31, 1972 [21] Appl. No.: 240,116

[52] U.S. Cl. ...l74/40 R, 174/146 [5 1] Int. Cl. ..H02g 7/12 [58] Field of Search ..l74/40 R, 42, 146

[56] References Cited UNITED STATES PATENTS Torr ..l74/l46 X Jan. 16, 1973 [57] ABSTRACT A device for spacing electrical conductors which are used in high voltage transmission lines. The device includes a central hub provided with two or more cavities. A rigid arm articulately extends into each cavity. The arm is provided at one end with a truncated double cone or knob-like structure and the other end is provided with means for holding the conductor. Interposed between the inside walls of the cavity and the knob of the rigid arm, within each cavity, is an elastomeric sleeve having a substantially circumferentially continuous groove arranged adjacent to and alongside of the intersection of the two cones which comprise the knob.

4 Claims, 3 Drawing Figures CABLE SPACERS FOR ELECTRICAL OVERHEAD TRANSMISSION LINES The invention relates generally to spacer devices for spacing two or more electrical cable conductors in overhead transmission lines and, more particularly, concerns the manner in which the conductors are resiliently constrained.

Cable spacers of the type herein under consideration are well known in the art and comprise generally a hub provided with two or more cavities for receiving an articulately disposed rigid arm which in turn has means arranged remote from the hub to clampingly receive the cable. The arm terminates in the cavity with a knob having a truncated double cone-like configuration. lnterposed between the knob and the walls of the cavity is an elastomeric sleeve which resiliently constrains the movement of the arm and causes the arm to return to a neutral position after the conditions which have caused such movement have subsided. Generally, the movement of such arms is induced by wind forces which are counteracted by the elastomeric sleeve. A detailed description of such a device can be found in U. S. Pat. No. 3,157,731.

In devices of the type described above, it has been found that angular movement of the double truncated cone knob within the cavity has the tendency to place the elastomeric sleeve under shear stress. This causes displacementpr so-called slippage, of all or part of the sleeve in the region defined by the intersection or juncture of the cones along its circumference, i.e., the location of the maximum diameter of the knob.

The phenomenon of slippage occurs when the elastomeric sleeve is subjected to excessive shear stresses at the critical region or intersection of the double truncated cone. More specifically, a relative movement between the double truncated cone OD and the corresponding elastomeric sleeve lD results in a permanent slippage displacement. Once this slippage has taken place the truncated cone or spacer arm fails to return on its own to its original or neutral position, and consequently it fails to maintain a constant conductor spacing which is the prime function of this spacer. Furthermore, a frequent occurrence of this type of cycling condition, which does occur as a result of wind induced vibrations, will establish abrasive conditions accelerating the failure of the elastomer due to a conversion and breakdown of the coherent elastomeric material into granular-like substances which are devoid of the desired elasticity.

As has been noted above, the spacers are used on overhead transmission lines. It is thus not feasible to frequently check whether the elastomeric sleeve has deteriorated, without considerable effort and expenditure.

It is therefore the primary object of the present invention to improve spacing devices of the type described above in which the movement or slipping of the elastomeric sleeve is minimized and the volume of and pressure application upon the elastomeric material in the critical region, i.e., in the region adjacent to the juncture of the two truncated cones forming the knob, is substantially reduced.

lt is a still further object of the present invention to provide a spacer device having a hub provided with a cavity for receiving a rigid arm and in which the elastomeric sleeve interposed between the cavity walls and the knob has reduced wall thickness areas in the region adjacent to the juncture of the two cones forming the knob.

An aspect of the present invention resides in the provision of a spacer device for the spacing of two or more individual conductors of an overhead electrical transmission line. The spacer device includes a rigid hub formed with a cavity in the periphery thereof with the cavity being formed generally with a mirror image of a double truncated cone. A rigid arm extends articulately with one end into this cavity and the arm is provided at that end with a knob which has, generally, the configuration of a double truncated cone of a shape similar to but smaller in overall dimension than the inside walls of the cavity. The outside surfaces of the knob converge towards the maximum diameter of the double cone and at that location merge to establish a curved juncture; the axis across the diameter of the juncture extends perpendicularly to the longitudinal axis of the arm. An elastomeric sleeve is interposed between the knob and the walls of the cavity with the sleeve embracing at least partially the converging surfaces of the sleeve. The internal face of the sleeve has a groove extending along and facing the circumference of the double cone curved juncture.

Another aspect of the present invention resides in the provision of a device of the type described in the preceding paragraph in which the groove of the sleeve is dimensioned in such a manner that the width thereof approximates the curved portion of the juncture region.

A still further aspect of the present invention resides in providing a spacer device of the type referred to above in which the groove of the sleeve is relatively deep and approximates percent of the thickness of the sleeve. In order to facilitate assembly, the sleeve may comprise two half shells and in the assembled condition the groove is circumferentially continuous.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawings:

FIG. 1 shows a plan view of a hub and one arm of a spacing device shown partly in section with the remaining arms being shown partly fragmentary;

FIG. 2 is a cross-sectional view of the half shell of the elastomeric sleeve; and

FIG. 3 is a substantially diagrammatic illustration of the movement of the knob relative to the sleeve and the hub; as shown, for simplification, the elastomeric sleeve is illustrated as not being under pre-compression.

Referring now to the drawings, there is shown a spacing device having a hub 10 composed of two half shells, or discs (not shown) which are secured together by means of rivets 12. The central hub l0 is provided with a plurality of cavities 14 in the periphery thereof with each cavity having, generally, the mirror image of a double truncated cone. The number of cavities will depend upon the application for which the invention is intended and may range from 2 to usually not more than 12. Each cavity is adapted to receive one end of a rigid spacer arm 16 of the type well known in the art. The arm 16 extends articulately into the cavity 14 with a knob 18 having generally the configuration of a double truncated cone of a shape similar to but smaller in overall dimension than the cavity 14. The outside surfaces of the knob 18, see 180 and 18b of FIG. 3, converge towards the maximum diameter of the double cone, see 180. This is the location where the generally flat surfaces 180 and 18b merge in such a manner so as to establish a curved juncture 20. In other words, the region 20 of the curved junction is in the location defined by the intersection between each cone, of the double cone, and encompasses the peripheral area of the knob which is curved. This intersection, or the axis across the diameter of the juncture, extends perpendicularly to the longitudinal axis of the arm 16. The knob is usually adapted to make an angular movement of about degrees from the neutral longitudinal axis.

lnterposed between the knob 18 and the internal walls of the cavity 14 is an elastomeric sleeve 22 which embraces,at least partially, the converging surfaces, or flat sides, 18a and 18b of the knob. The sleeve 22, to facilitate assembly, is made of two half shells (not shown) and the total configuration thereof is similar to a double truncated cone providing again a mirror image of both the cavity 14 and the knob 18, except that the axial ends 24 are open in order to permit articulation of the knob 18 or to avoid interference with such movement.

The internal face of the sleeve 22 is provided with a circumferentially extending groove 26 which, in assembled condition within the cavity, extends along and faces the circumference 'of the double cone curved juncture or region 20. v

In order to minimize the amount of elastomeric material which is distended or can cause slippage in the critical region, i.e., in the region adjacent to curved juncture 20, the width of the groove 26 approximates the curved portion of the juncture. It has been found to be desirable to make the groove 26 as deep as possible. From a practical point of view, the optimal maximum depth appears to be approximately 75 percent of the thickness of the sleeve. From an operating point of view, it may be desirable, indeed advantageous, to remove even more elastomeric material in this critical region; however, for ease of manufacture of the part, particularly during the molding operation, it is advantageous to maintain the integrity of the main body of the elastomeric sleeve and therefore a removal of not much more than percent of the material in the grooved region is desirable.

When the two half shells are assembled they provide a substantially continuous groove around the circumference of the knob in juxtaposition or adjacent to the curved juncture.

While a three-cable spacer unit is illustrated in FIG. 1, it is obvious that the invention is not limited to any number of spacer arms that may be used with a hub 10.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

hat is claimed is:

l. A spacer device for spacing two or more individual conductors of an overhead electrical transmission line, comprising:

a rigid hub formed with a cavity in the periphery thereof having generally the mirror image of a double truncated cone;

a rigid arm extending articulately with one end into said cavity and provided at said end with a knob having generally the configuration of a double truncated cone of a shape similar to but smaller in overall dimension than said cavity;

the outside surfaces of the knob converging towards the maximum diameter of the double cone and merging, establishing a curved juncture, the axis across the diameter of the juncture extending perpendicular to the longitudinal axis of the arm;

and an elastomeric sleeve between said knob and the walls of the cavity embracing at least partially the converging surfaces, said sleeve having a groove in the internal face extending along and facing the circumference of the double cone curved juncture.

2. A device according to claim 1, wherein the width of said groove approximates the curved portion of the juncture.

3. A device according to claim 1, wherein the depth of said groove approximates 75 percent of the thickness of the sleeve.

4. A device according to claim 1, wherein said sleeve comprises two half shells providing in assembled condition a substantially continuous groove adjacent to said curved juncture.

Claims

1. A spacer device for spacing two or more individual conductors of an overhead electrical transmission line, comprising: a rigid hub formed with a cavity in the periphery thereof having generally the mirror image of a double truncated cone; a rigid arm extending articulately with one end into said cavity and provided at said end with a knob having generally the configuration of a double truncated cone of a shape similar to but smaller in overall dimension than said cavity; the outside surfaces of the knob converging towards the maximum diameter of the double cone and merging, establishing a curved juncture, the axis across the diameter of the juncture extending perpendicular to the longitudinal axis of the arm; and an elastomeric sleeve between said knob and the walls of the cavity embracing at least partially the converging surfaces, said sleeve having a groove in the internal face extending along and facing the circumference of the double cone curved juncture.