CN102957002B - Swaged connectors for enhanced cable tension - Google Patents

Abstract

The present invention relates to a swaged connector for a tension state of a reinforced cable. The improved cable connector includes a connector insert having an axial bore sized to receive the core of the reinforced cable. The connector body has a substantially cylindrical outer surface and a substantially cylindrical cavity. A distal portion of the cavity is sized to receive a connector insert. A second portion of the lumen proximally displaced from the distal portion is sized to receive the twisted conductors of the cable. The connector body may be configured with one or more additional portions of the cavity having progressively larger diameters, the number of portions depending on the size of the cable. Alternatively, the inner surface of the cavity may have a slight taper. Using a single die, the connector body is compressed with a swaging tool at a plurality of axially spaced locations to grip the stranded conductor and also to grip the connector insert.

Description

Swaged connectors for enhanced cable tension

Cross References to Related Applications

This application is a continuation-in-part of application number 13/274,503 filed on October 17, 2011.

technical field

The present invention relates to the field of power transmission and in particular to a full tension connector for a reinforced cable having a load-carrying core surrounded by stranded conductors, for substations and high voltage power transmission lines.

Background technique

High-capacity, high-strength reinforced stranded cables are commonly used for overhead power lines. An example of such a cable is Aluminum Steel Core (ACSR). In ACSR, the outer strands are chosen to be aluminum because of its excellent electrical conductivity, light weight and low cost. The outer strands surround one or more central steel strands that provide the strength needed to support the weight of the cable without stretching the extensible aluminum strands. This gives the cable an overall higher tensile strength than a cable consisting only of aluminum stranded conductors. Other types of reinforced cables having a load-carrying core surrounded by stranded conductors include, but are not limited to, aluminum-clad steel conductors (ACSS), aluminum-clad steel conductors (ACSS/AW), steel Core ladder cross-section annealed aluminum stranded wire (ACSS/TW), aluminum alloy cored aluminum stranded wire (ACAR) and aluminum conductor composite core (ACCC).

Connectors play an important role in the efficiency and reliability of power transmission systems. Cables for overhead transmission lines require connectors and dead end assemblies for splices. Commonly assigned US Patent No. 7,874,881 discloses tension state fittings for all aluminum cables. However, this fitting may be used with reinforced cables having a load-carrying core surrounded by stranded conductors, the resulting connection not being able to withstand the same high tensile loads that the cable itself is designed to withstand. Connectors for reinforced cables typically include a two-part assembly having a connector body and an insert or core clip. The insert is first fastened to the cable core and then the connector body is fastened to the insert and the cable conductors. For swaged connectors, this requires two dies of different sizes.

Contents of the invention

The present invention provides an improved cable connector having an insert having an axial bore sized to receive a cable core. The connector body has a generally cylindrical outer surface and a generally cylindrical cavity. A distal portion of the lumen having a first substantially cylindrical inner surface is sized to receive a connector insert. A second portion of the lumen proximally displaced from the distal portion has a second, substantially cylindrical inner surface sized to receive the twisted wires of the cable. The connector body may be configured with one or more additional portions of the cavity having a substantially cylindrical inner surface of increasing diameter, the number of which depends on the size of the cable. Alternatively, the inner surface of the cavity may have a slight taper. Using a single die, a swage tool compresses the connector body at a plurality of axially spaced locations to clamp the stranded conductors and also the connector insert, thereby clamping the core of the cable. Alternatively, using two different moulds, the connector core may be compressed after the core of the cable is inserted, but before the connector core is inserted into the connector body.

Description of drawings

Figure 1 is a cross-sectional view of an ACSR cable;

Figure 2 is a side view of a connector according to an embodiment of the present invention mounted on a cable;

Figure 3 is a cross-sectional view through the connector and cable shown in Figure 2 along the line A-A;

Figure 4 is a perspective view of a first type of connector insert;

Figure 5 is an end view of the connector insert shown in Figure 4;

Figure 6 is a perspective view of a second type of connector insert;

Figure 7 is an end view of the connector insert shown in Figure 6;

Figure 8 is a perspective view of a third type of connector insert;

Figure 9 is an end view of the connector insert shown in Figure 8;

10 is a perspective view of a fourth type of connector insert;

Figure 11 is an end view of the connector insert shown in Figure 10;

Fig. 12 is a sectional view of the connector body shown in Fig. 2;

Figure 13 shows a swaged area on the connector body;

14 is a sectional view of a connector body according to another embodiment of the present invention.

detailed description

In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods and apparatus are omitted so as not to obscure the description of the present invention with unnecessary detail.

The invention has been described with reference to ACSR cables. However, the invention is also applicable to ACSS, ACSS/AW, ACSS/TW, ACAR, ACCC and other reinforced cables having a load-carrying core surrounded by stranded conductors. The core may comprise steel, high strength aluminum alloy or composite material, and the stranded conductors may comprise aluminum, copper or alloys thereof.

A common type of ACSR cable 10 is shown in FIG. 1 . This particular type of cable, having the trade designation 26/7, has twenty-six outer aluminum conductors 12 surrounding a core 14 comprising seven steel strands. As noted above, the steel core is the primary contributor to the tensile strength of the cable 10 .

A connector 20 according to one embodiment of the present invention is shown in FIGS. 2 and 3 . The connector body 22 has a generally cylindrical outer surface and has a bored central cavity 24 extending from a proximal end 26 to an annular seating surface 28 . Connector insert 30 is inserted into cavity 24 and seats against seating surface 28 . The aluminum strands at the end of the cable 10 are removed a distance approximately equal to the length of the connector insert. The end of the cable 10 is inserted into the cavity 24 and the steel core 14 fits into the central axial bore in the connector insert 30 and the truncated ends of the aluminum strands are enclosed in the proximal portion of the cavity 24 . Once assembled in this manner, the connector 20 is secured to the end of the cable 10 using a number of swaging dies as described below.

Connector 20 may be configured as a splice connector with a tubular body that receives a cable at each end, or as a tensioned termination with a suitable structural coupling (such as a hole or clevis) at the distal end of the body. . Alternatively, terminal structural couplings may be incorporated into the connector insert. Connector body 22 may be fabricated from a suitable aluminum alloy such as 3003-H18.

The connector insert 30 may be constructed as a simple tubular body 300 as shown in Figures 4 and 5 or may be constructed according to one of several other designs. One such design is shown in FIGS. 6 and 7 . The connector insert 310 is configured as a tube having a central axial bore 312, and in cross-section, spokes 314 project radially outward from an annular region 316 surrounding the central bore. Another connector insert design is shown in FIGS. 8 and 9 . The connector insert 320 is configured as a tube with a central axial bore 322 and, in cross-section, spokes 324 protruding radially inwardly from an outer annular portion 326 . Yet another connector insert design is shown in FIGS. 10 and 11 . Connector insert 330 is generally tubular configuration having a central axial bore 332 and a plurality of axially extending slots 334 similar to collet chucks. The scope of the present invention is not limited to these specific configurations. Other configurations of connector inserts may be used to grip the core of the cable when swaging the connector body around the connector insert. The connector insert may have aluminum oxide or other suitable abrasive bonded to the inner surface of the axial bore to increase the mechanical clamping force on the core of the cable. Alternatively, the inner surface of the axial bore may be machined with internal threads, circumferential teeth or other surface finish to increase the clamping force of the connector insert on the core of the cable. Additionally, the connector insert rather than the connector body may incorporate structural couplings of the terminal connector, such as holes or clevises. The connector insert can be fabricated from a suitable aluminum or steel alloy such as 6061-T6 aluminum or tool steel.

FIG. 12 is a sectional view of the connector main body 22 showing the internal structure. In the part A of the connector body into which the connector insert is inserted, the cavity 24 has _a diameter d ₁ which is only slightly larger than the outer diameter of the connector insert. Moving from portion A towards the proximal end 26 of the connector body, the diameter of the lumen gradually increases. Each such step transmits a different pressure to the cable and acts to distribute the swaging load to all the aluminum strand layers in the ACSR cable. Portion B of lumen 24 proximally adjacent to portion A has a diameter _d2 . As shown here, d ₂ is greater than d ₁ . However, part B may have the same diameter as part A. Portion C of lumen 24 proximally adjacent portion B has a diameter d ₃ that is greater _{than diameter d 2 .} Additionally, proximally displaced portions of lumen 24 may have further increasing diameters. The number of steps can be fewer or more than shown in the figures and is generally determined by the size of the cable.

Referring now to FIG. 13 , after the cable and connector insert have been inserted into the cavity 24, the outer connector body is swaged in a number of locations so that it surrounds the aluminum strands of the cable and the connections that clamp the steel strands of the cable The inserts are evenly secured. The swaging operation is preferably performed using a 360° radial swaging tool manufactured by DMC Power, Inc. (Gardina, California). The connector body is swaged in part A to secure the connector insert and the steel core of the cable. Multiple stacked swages may be required to adequately secure the cable insert. The connector body is also swaged in sections B and C to secure the aluminum stranded wires. As the inner diameter of the connector body decreases, the compression ratio and compressive stress in each part increases by about 3% to 20%. There is a spacing or gap, denoted D, between any successive swages on the aluminum strand. A spacing in the range of about 0.1" to 0.5" allows the aluminum strand to splay behind the swage and lock the cable behind the swage when it is under tension. In addition, there is a gap D2 between the swaging dies in Section A and Section B, which also allows the stranded conductors to splay. The swage in section A that holds the connector insert and the steel core of the cable set in it have the primary function of transmitting the tensile load of the cable through the connector, while in sections B and C (and any further increased The swage in the additional portion of the inner diameter) adds tensile strength, but also serves the function of establishing electrical conductivity between the cable and the connector. Since the outer connector body has a uniform diameter, only a single die is required to swage the connector body in each of Section A, Section B, and Section C.

As with prior art connectors for reinforced cables, it is also possible to attach the connector 20 to the cable using two dies in a slightly different series of steps. In cases where the connector insert can be a simple tube as shown in Figures 4 and 5, first the connector insert can be swaged to the cable core with a die of small size compared to the outer diameter of the insert superior. The connector body can then be swaged onto the connector insert and cable conductors with a die having a larger dimension compared to the outer diameter of the connector body. In this case, the stranded conductors at the end of the cable 10 are first removed by a distance approximately equal to the length of the connector insert, as described above. The exposed core at the end of the cable 10 is inserted into a central radial bore in the connector insert 30 and the connector insert is swaged to the cable core using an appropriately sized die. The connector insert is then inserted into the cavity 24 of the connector body 22 until the connector insert abuts the seating surface 28 . The connector body is then swaged onto the connector insert and the stranded conductors of the cable, as described above.

FIG. 14 is a cross-sectional view of a connector body 220 according to another embodiment of the present invention. While the lumen 24 of the connector body 22 is stepped, the lumen 240 of the connector body 220 gradually changes from d ₁ to d ₄ at section E. As shown in FIG. This configuration also results in each swage applied to the connector body within section E, depending on the inner diameter at each swage location, to impart different compression ratios and compressive stresses to the cable in order to distribute the swage load into the cable all stranded conductor layers.

It should be understood that the invention described above may be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. It is therefore to be understood that the invention is not limited to the details shown above, but is only limited by the appended claims.

Claims (4)

1. connector is attached to have by stranded conductor around the method for power cable of core, described method comprises:

There is provided connector, described connector comprises: connector insert, and described connector insert has the axial drilling being dimensioned to the described core receiving described cable, and connector body, described connector body has the opening of the near-end at described connector body, and there is substantially cylindrical outer surface, described opening with there is the chamber being dimensioned to the distal part receiving described connector insert be communicated with, described distal part has the first inner surface of the first internal diameter, described chamber also has the Part II that distally part proximad is arranged, described Part II has the second inner surface of the second internal diameter, described second inner surface is dimensioned to and receives described stranded conductor, wherein, described second internal diameter is greater than described first internal diameter, described chamber also has at the nearside Part III adjacent with described Part II, and described Part III is also for receiving described stranded conductor and having the 3rd inner surface of the 3rd internal diameter, and wherein said 3rd internal diameter is greater than described second internal diameter,

Remove a part for the end close to described cable of stranded conductor to expose the corresponding part of described cable core;

By the described boring be inserted partially in described connector insert of exposing of described cable core;

The described end of described cable be inserted into the described chamber of described connector body thus make described connector insert be inserted into the described distal part in the described chamber in described connector body and described stranded conductor is inserted into the described Part II in described chamber;

With the described connector body of at least the first pressure compaction around the described distal part in described chamber;

With the described connector body of the second pressure compaction around the described Part II in described chamber;

With the described connector body of the 3rd pressure compaction around the described Part III in described chamber;

Wherein, to the compression of the described outer surface of the described connector body of the described Part III around described chamber with axially spaced about 0.1 inch to 0.5 inch to the compression of the described outer surface of the described connector body of the described Part II around described chamber, thus described stranded conductor is opened between the pressing section of described connector body.

2. method according to claim 1, wherein, uses swaging tool to perform the step of the described outer surface compressing described connector body.

3. method according to claim 1, wherein, described method also comprises, and before the described chamber described end of described cable being inserted into described connector body, compresses described connector insert to engage the described part being inserted into described connector insert of described cable core.

4. method according to claim 3, wherein, uses swaging tool to perform the step compressing described connector insert.