JP3070789B2 - How to connect stranded steel wires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a crimping sleeve for a steel stranded wire composed of a single central strand used for a tension member such as an optical fiber cable and six outer strands wrapped around the central strand. The present invention relates to a method of connecting steel stranded wires to be connected.

[0002]

2. Description of the Related Art FIG. 2 is a cross-sectional view of a steel stranded wire used for a tension member of an optical cable or the like, in which six outer wires 22 are arranged at an appropriate pitch around one central wire 21. It is configured by twisting.

FIGS. 3A and 3B are explanatory views of an example of a method for connecting the above-described steel stranded wires. As shown in the drawing, the ends of the steel stranded wire 2 are inserted from both sides of the crimping sleeve 10 at equal lengths, and the crimping sleeve 10 is caulked at a plurality of locations 10a and connected. At this time, as the material of the crimping sleeve 10, general steel having high strength is usually used.

[0004]

As described above, in the structure of the stranded steel wire, the center strand is straight, and six outer strands are twisted around the center strand at an appropriate pitch. ing. Therefore, when such a steel wire is crimped and connected by a crimping sleeve, the inner surface of the crimping sleeve and the six outer layer wires are in contact with each other and the frictional force is strong, but the center wire does not contact the inner surface of the crimping sleeve, and Because of the linear shape, when the tensile load applied to the connecting portion increases, only the central strand starts moving in a direction in which the center strand comes off from the crimp sleeve before the surrounding six outer strands,
The caulked portion is gradually deformed and loosened, and eventually the whole is pulled out. Also, since the crimping sleeve made of general steel is used, it is hard. Even if it is crimped, the inner surface of the crimping sleeve does not easily fit into the entire steel stranded wire, the six outer wires slide, the frictional force is weak, and the tensile load at the connection part There was a problem of being small.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a method for connecting a steel stranded wire by caulking a crimping sleeve which is easy to operate and has a large tensile strength at a connecting portion. The feature is that the material of the crimping sleeve is soft iron, and after cutting the center strand of the steel stranded wire by the length to be inserted into the crimping sleeve, it is restored again, and the surface of the steel stranded wire is sandpaper etc. Rinsing, and then inserting into a crimping sleeve and caulking at multiple locations to connect.

[0006]

In the connection method of the present invention described above, since the central strand of the steel stranded wire is cut and caulked with the crimping sleeve, no tensile load is applied to the central strand of the connection portion. Therefore, at the connection portion, a tensile load is applied only to the six outer layer wires, and the center wire does not move, so that the caulked portion does not deform. In addition, by roughening the outer surface of the steel stranded wire with sandpaper, etc., the frictional force with the inner surface of the crimping sleeve increases, and by using soft iron for the crimping sleeve, the inner surface of the crimping sleeve becomes the outer layer wire of the steel stranded wire. Get in between. By such an action, the tensile strength of the connection part is remarkably improved.

Table 1 shows the measurement results of tensile strength when a 7 / 2.3 mm steel stranded wire was connected. According to the connection method of the present invention, the tensile strength of the connection is 6/6 of the minimum tensile load of the steel stranded wire.
A strength close to 7 (one is cut) is obtained.

[0008]

[Table 1]

[0009]

1 (a) to 1 (d) are explanatory views of the procedure of a specific example of the connection method of the present invention. FIG. 1A shows a crimp sleeve 1 made of soft iron. First, the outer strand 22 of the steel strand 2 is expanded and the center strand 21 is cut. Reference numeral 21a denotes a cut center strand, and the cut length l is 1/2 of the length L of the crimping sleeve 1 (FIG. 1, b). Subsequently, as shown in FIG. 1C, the cut center wire 21a is inserted into the center of the steel stranded wire 2 again, and the surface of the 226 outer layer wires is roughened with sandpaper or the like. Thereafter, the steel stranded wire 2 is inserted from both sides of the soft iron crimping sleeve 1, and caulking is performed at a plurality of places 1 a (FIG. 1, d) using a caulking tool or the like, and the connection is completed. Although the embodiment has been described with respect to the connection between the stranded steel wires, it is needless to say that the present invention can also be applied to a terminal processing section of an optical cable such as a bend end of an optical cable.

[0010]

As described above, according to the method for connecting steel wires of the present invention, a high-strength connection portion which is simple in operation and close to 6/7 of the tensile strength of a stranded steel wire can be obtained. Generally, an optical cable uses a steel stranded wire as a tension member. When connecting the optical cable, the connection strength of the tension member becomes the tensile strength of the optical cable connecting portion, and it is desirable that the optical cable connecting portion be closer to the tensile strength of the optical cable itself. Therefore, although various methods have been devised as a method of connecting the steel stranded wires and a method of forming the tow end, use of a compact and inexpensive crimping sleeve crimping method, which is simple in connection work and formation of the tow end, has been conventionally used. Was required. However, it has not been practically used due to insufficient tensile load. It is extremely effective to use the connection method of the present invention for connecting such an optical cable and forming a terminal portion.

[Brief description of the drawings]

FIGS. 1A to 1D are explanatory views of the procedure of a specific example of a method for connecting a steel stranded wire according to the present invention.

FIG. 2 is a cross-sectional view of a stranded steel wire used for a tension member or the like of an optical cable.

FIGS. 3 (a) to 3 (b) are explanatory views of a conventional method of connecting a steel stranded wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Soft iron crimping sleeve 1a Caulking part 2 Steel stranded wire 21 Center strand 21a Cut center strand 22 Outer layer strand 3 Rough surface

Claims (1)

(57) [Claims] 1. A method for connecting a steel stranded wire having a single central wire around which six outer wires are stranded by using a crimping sleeve, wherein a material of the crimping sleeve is Using soft iron, cut the center strand of the steel stranded wire by the length inserted into the crimping sleeve, return it to its original position, roughen the surface of the steel stranded wire with sandpaper, etc., and then insert it into the crimping sleeve. A method of connecting steel stranded wires, characterized in that they are connected by caulking at multiple locations.