JPH06250056A - Structure of loose tube - Google Patents

Abstract

PURPOSE:To form an aperture for taking out coated fibers by using a blade, such as ordinary cutter knife, by projectingly providing a sheath with hollow projecting line parts and setting the size between the inside surfaces at the roots of the hollow projecting line parts smaller than the minor diameter of the coated optical fibers housed in the sheath. CONSTITUTION:The sheath 1 is projectingly provided with one or plural hollow projecting line parts which extend in the longitudinal direction of the sheath and outward in the radial direction. The size C between the inside surfaces at the roots of the hollow projecting line parts is set smaller than the minor diameter of the coated optical fibers housed in the sheath 1. The aperture can be formed in the sheath by cutting away a part of the one or plural hollow projecting line parts which extend in the longitudinal direction of the sheath and outward in the radial direction by means of the blade, such as ordinary cutter knife. The size between the inside surfaces at the roots of the hollow projecting line parts is smaller than the minor diameter of the coated optical fibers housed in the sheath and, therefore, the intrusion of a part of the coated optical fibers into the hollow projecting line parts does not arise even if the coated optical fibers are formed into any shapes. Then, the aperture is easily and rapidly formed without paying special attention.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION When connecting a branch line in the middle of a covered communication line, a part of the cover in the middle of the communication cable must be cut and removed. The present invention, without using a special cutting jig, safely performs the above cutting work of the coating,
The present invention relates to a structure of a loose tube (a covering tube for a communication wire that loosely covers a large number of single wires and the like together with a jelly-like compound) that can be easily performed.

[0002]

2. Description of the Related Art Various methods are used to remove a part of the sheath of a loose tube, such as removing with a dedicated cutter or a dedicated jig like a planer.
Among them, the method of using a dedicated kanna-like jig is the most efficient and is safe with less risk of damaging the core wire. However, when removing the sheath of the loose tube, even when using a jig like a planer, when the cutting edge hits the core wire of the loose tube, the core wire moves in the jelly-like compound of the loose tube and escapes. However, if the core wire cannot escape freely, it is often damaged at the cutting edge. Especially, the risk is great when the core wire is a tape core wire. In any of these conventional techniques, a special jig must be prepared, and the cutting edge of the jig is cut into the inside of the jacket, so that the inner core wire is not damaged by the cutting edge. However, the work efficiency is poor. The above problem is caused by the fact that the cutting edge is cut into the inside of the coating to form an opening for taking out the core wire in a part of the outer cover.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, and for that purpose, a normal cutter such as a cutter knife is used to partially cut the inside of the jacket without cutting the blade edge. It is an object to devise the structure of the jacket so that the opening for taking out the core wire can be formed in the inner part.

[0004]

[Means for Solving the Problems] The measures taken for solving the above problems are constituted by the following elements (a) and (b). (A) One or a plurality of hollow ridges that extend in the longitudinal direction of the jacket and project outward in the radial direction, and (b) the dimension between the inner surfaces of the roots of the hollow ridges is outside. The diameter must be smaller than the short diameter of the optical fiber core. The "hollow ridge" generally means a shape in which a part of the outer cover is picked up and protruded in the radial direction in principle. A projecting space similar to the hollow projecting portion may be formed in any shape, regardless of the cross-sectional shape of the jacket. Further, the above-mentioned "minor diameter" of the optical fiber core wire means the thickness (the minor diameter when the cross section is an ellipse) when the optical fiber core wire is the tape core wire, and when the cross sectional shape is circular. Means its diameter.

[0005]

[Operation] It is possible to form an opening in the jacket by extending in the longitudinal direction of the jacket and cutting a part of one or more hollow ridges outward in the radial direction with a blade such as an ordinary cutter knife. it can. In this case, the cutting edge of the cutting tool does not cut into the internal space of the jacket in which the cord is housed. Since the dimension between the inner surfaces of the roots of the hollow ridges is smaller than the minor axis of the optical fiber housed in the jacket, no matter what shape the optical fiber core wire has, part of it is hollow. It does not enter the ridge. Therefore, when cutting a part of the hollow ridge portion with the blade, the blade edge of the blade never touches the inner core wire of the jacket. Therefore, it is possible to easily and quickly form the opening for taking out the core wire in the outer cover without paying special attention.

[0006]

EXAMPLES Next, examples will be described with reference to the drawings. The first embodiment shown in FIG. 1 is an example in which a hollow ridge portion 2 having a substantially circular cross section is provided to project outward in the radial direction of the jacket 1, and a constricted portion at the base of the hollow ridge portion 2 is provided. The dimension C between the inner surfaces of the tape is smaller than the thickness t of the tape core wire T housed in the jacket. The direction of the tape core wire with respect to the hollow ridge portion 2 is random in the state of being housed in the jacket 1, and a part of the tape core wire may be pressed against the inner surface of the jacket 1. Dimension C between the inner surfaces of the constriction at the base of the ridge 2.
Is smaller than the thickness t of the tape core wire T, so that part of the tape core wire T does not enter the hollow ridge portion 2. The second embodiment shown in FIG. 2 is an example in which a hollow ridge 2a having a substantially U-shaped cross section is provided outwardly in the radial direction of the jacket 1. The inner surface at the base of the hollow ridge 2a The dimension C ₁ therebetween is smaller than the thickness t of the tape core wire T housed in the jacket. Further, in the third embodiment shown in FIG. 3, hollow ridges 2b and 2c similar to the hollow ridges 2a shown in the second embodiment of FIG. 2 are provided on the jacket 1 at two opposing positions. It is a thing. The loose tube is usually twisted as a result, and in that case, in the second embodiment, the hollow ridge 2a is easily cut off at any position in the longitudinal direction. Not necessarily. For this reason, it may be difficult to perform the cutting operation depending on the place where the hollow ridge portion should be cut. However, in the third embodiment of FIG. 3, since there are two ridges at the positions where the hollow ridge portions face each other, the above problem is addressed. It is convenient to do this. The hollow ridge portion basically means a shape in which a part of the outer cover is picked up and protruded in the radial direction. However, as in the fourth embodiment shown in FIG. A protruding space 2d similar to the hollow ridge portion may be formed in the thick portion. For reference, an example of various dimensional relationships regarding a loose tube in which a large number of tape cores including 12 optical fiber cores are stored is as follows. The outer diameter D of the outer jacket 1 is 6 mm and the wall thickness of the outer jacket is 6 mm. S is 0, 5 mm, the height h of the hollow ridge is 1, 5 mm,
The dimension C between the inner surfaces of the base of the hollow ridge is 0, 2 mm,
The tape core wire has a width b of 3 mm and a thickness t of 0 and 3 mm.

[0007]

The invention which has solved the above-mentioned problems of the present invention is not known. Therefore, since the above-mentioned problem of the present invention is novel, it is the greatest effect peculiar to the present invention that this novel problem is solved to solve the above-mentioned problems of the prior art.
That is, according to the present invention, when connecting a branch line in the middle of a covered communication line, the work of cutting a part of the cover in the middle of the communication cable can be performed safely, easily, and quickly without using a special jig. The unique effect of being able to

[Brief description of drawings]

FIG. 1 is a sectional view showing the outline of a first embodiment.

FIG. 2 is a sectional view showing the outline of a second embodiment.

FIG. 3 is a sectional view showing the outline of a third embodiment.

FIG. 4 is a sectional view showing the outline of a fourth embodiment.

[Explanation of symbols]

1 ... envelope 2, 2a, 2b, 2c ... hollow protrusions 2d ... hollow ridges similar protruding space C, between the base of the inner surface of the C ₁ ... hollow ridges Dimension T ・ ・ ・ Tape core wire t ・ ・ ・ Tape core wire thickness

Claims (1)

[Claims] 1. A longitudinally extending direction of an outer jacket, wherein one or a plurality of hollow projecting ridges are provided on the outer cover in a radially outward direction, and the dimension between the inner surfaces of the roots of the hollow ridges is defined as the outer jacket. Loose tube structure that is smaller than the short diameter of the optical fiber core.