JP2016220319A - Anchoring method for drop cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drop cable anchoring method which is capable of adjusting a sagging degree equal to or more than anchoring using S-shaped hardware, makes fatigue rupture of a support wire part unlikely to occur and is capable of reducing an extra length of an element part.SOLUTION: The anchoring method includes: a first winding step for winding a winding part 32b at one side of a winding grip 30b including a hook part 31b and spiral winding parts 32b and 33b that are positioned at both sides of the hook part 31b, around a drop cable 1; an adjustment step for adjusting the sagging degree of the drop cable 1 by hanging the hook part 31b on an anchor part 11b and imparting a tension to the winding part 33b at the other side of the winding grip 30b with the anchor part 11b defined as a fulcrum; and a second winding step for winding the winding part 33b at the other side around the drop cable 1 in the state where the sagging degree of the drop cable 1 is adjusted.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a drop cable retaining method, and more particularly to a drop cable retaining method using a winding grip.

  Among overhead cables, suspension cables and thick and heavy self-supporting cables are difficult to adjust for sag due to their weight. For this reason, the drawing work is performed by adjusting the slackness using a wire tensioner, and using the winding grip (see Non-Patent Document 1), various hardware (see Non-Patent Document 2) constituting the holding portion of the support. ).

  On the other hand, the drop cable drawn into the building is very thin and lightweight (for example, 0.02 kg / m or less) compared to the above-described suspension line or the like, so the support line portion of the drop cable is narrow. Even if it is a difficult place, using a S-shaped hardware as a retainer (same as the “outdoor line retainer” in Non-Patent Document 2), the retention work is performed only by manual construction.

“Winded Grip”, [online], J-Wytex Corporation, [Search April 15, 2015], Internet <http://www.j-witex.co.jp/products/grip/index. html> "Communication Construction Materials General Catalog 7th Edition Outdoor Construction Materials", p.109-p.124, [online], Hirano Telecommunications Equipment Co., Ltd. [Search April 15, 2015], Internet <https: // www.hiranotsushin.jp/catalog/>

  By the way, the relational expression of sag, cable unit weight, span length, and tension is generally expressed by the following formula (1). “D” means sag, “W” means cable unit weight, “S” means span length, and “T” means tension.

  FIG. 9 is a diagram showing the principle that the sag increases in the conventional drawing method using S-shaped hardware. As shown in FIG. 9, when the support line part of the drop cable in which the support line part including the support line and the element part including the optical fiber are integrated to the S-shaped hardware, the support line part is plastically deformed. Although it is wound around the S-shaped hardware, since it is a manual work, a slight slack may occur in the support line portion when winding around the S-shaped hardware (see FIG. 9A). When tension is applied to the support wire portion in a state where the slack has occurred, the support wire portion slides against the S-shaped hardware so as to absorb the length of the slack, and the S-shaped hardware is tightened by the support wire portion. Therefore, the length of the support line portion that is spanned increases by the amount of slip (see FIG. 9B). This increase in the length of the support line portion corresponds to an increase in the span length “S” in the above formula (1), and the sag increases in proportion to the square of the length of the support line portion. There is concern about the lack of separation of the ground height of the drop cable between the spans.

  FIG. 10A shows a state in which the support wire portion is wound around the S-shaped hardware, and FIG. 10B shows the winding of the plastic deformation portion of the support wire portion around the S-shaped hardware from the state of FIG. Indicates the unraveled state. As shown in FIG. 10, it is confirmed that stress is concentrated due to external force such as wind pressure load at the plastic deformation part of the support wire part plastically deformed for winding around the S-shaped hardware, and the support wire is fatigued and fractured. Has been. FIG. 11 shows a cross section of a support line that has undergone fatigue fracture due to conventional holding using an S-shaped hardware.

  FIG. 12 is a diagram illustrating the extra length of the element portion generated by the conventional holding using the S-shaped hardware. As shown in FIG. 12, when the drop cable is retained on the S-shaped hardware, the support wire portion formed in the same length and integrated with the element portion is separated, and then the support wire portion is retained. However, since a winding length of a predetermined length is required to secure the gripping force with the S-shaped hardware, an extra length of the element portion is generated. The extra length portion of the element portion may be disconnected due to external factors such as crow stagnation or increased weight due to snowfall, and there is concern about the reliability of the equipment.

  In view of the above-described problems, the object of the present invention is to adjust the slackness equal to or higher than the retention using the S-shaped hardware, and the support wire portion is not easily broken by fatigue, and the extra length of the element portion can be reduced. It is to provide a drop cable retention method.

  The drop cable drawing method according to the present invention includes a hooking portion that can be hooked on a holding portion of a support and a winding grip provided on one side of a winding grip provided with spiral winding portions located on both sides of the hooking portion. A first winding step of winding a portion around a drop cable, and hooking the hooking portion on the retaining portion, and applying tension to the winding portion on the other side of the winding grip with the retaining portion as a fulcrum. An adjustment step for adjusting the slackness of the cable, and a second winding step for winding the winding portion on the other side around the drop cable in a state in which the slackness of the drop cable is adjusted.

  ADVANTAGE OF THE INVENTION According to this invention, the slack adjustment method of the drop cable which can adjust the slackness equal to or more than the retention using the S-shaped hardware, is less likely to break the fatigue of the support wire portion, and can reduce the extra length of the element portion. Can be provided.

It is a figure which shows the drop cable fastened by the retention part using the winding grip. It is a flowchart which shows the retention method of the drop cable as one Embodiment of this invention. It is a figure which shows the state after performing step S4 shown in FIG. It is a figure which shows the state which hooked the hook part of the winding grip on the L-shaped metal fitting of the utility pole in step S5 shown in FIG. It is a figure which shows the state which applied tension | tensile_strength to the winding part of the other side of a winding grip from the state shown in FIG. It is a figure which shows the state which wound the winding part of the other side of a winding grip to the other end side of a drop cable, and completed the securing from the state shown in FIG. It is a figure which shows the formation method of the winding grip of a linear state. It is a figure which shows the modification of the retention part shown in FIG. It is a figure which shows the principle which sag increases in the conventional drawing method using S-shaped hardware. It is a figure which shows the plastic deformation location generate | occur | produced by the conventional holding using S character metal fittings. It is a figure which shows the cross section of the support line which carried out the fatigue fracture | rupture by the conventional holding using S character metal fittings. It is a figure which shows the extra length of the element part which generate | occur | produces by the conventional holding using S character metal fittings.

  Hereinafter, embodiments of a drop cable retaining method according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the member which is common in each figure.

  FIG. 1 shows a state in which the drop cable 1 is held to the L-shaped metal piece 11a attached to the electric pole 10a and the L-shaped metal piece 11b attached to the electric pole 10b using the winding grips 30a and 30b. FIG.

  The drop cable 1 includes a support wire portion 2 and an element portion 3.

  The support wire part 2 is defined by Japanese Industrial Standards (JIS), and has an outer diameter of 1.2 mm, one support wire made of a hard steel wire or a piano wire, and a flame retardant covering the periphery of the support wire And a covering portion made of a polymer compound such as polyethylene, and a wire having a substantially circular cross section.

  The element part 3 is comprised by the optical fiber core wire, the tension body, and the coating | coated part which coat | covers an optical fiber core wire and a tension body.

  The covering portion of the support wire portion 2 and the covering portion of the element portion 3 are integrally formed through a connecting portion located between them, and when the drop cable 1 is drawn, the support wire portion 2 and the element The part 3 is separated at the position of the connecting part, and the drawing operation of the support line part 2 is performed.

  An L-shaped metal piece 11a is attached to the electric pole 10a as a support, for example, via a metal band member 12a, and the L-shaped metal piece 11a constitutes a retaining portion of the electric pole 10a. Similarly, an L-shaped metal piece 11b is attached to the electric pole 10b as a support through, for example, a metal band member 12b, and the L-shaped metal piece 11b constitutes a retaining portion of the electric pole 10b.

  The winding grips 30a and 30b have the same shape, and the winding grip 30a is used to hold one end portion of the support wire portion 2 of the drop cable 1 to the L-shaped hardware 11a attached to the utility pole 10a. It has been. Further, the winding grip 30b is used to hold the other end portion of the support wire portion 2 of the drop cable 1 to the L-shaped metal piece 11b attached to the utility pole 10b.

  More specifically, the winding grip 30a is a hook portion 31a that can be hooked to the L-shaped metal piece 11a of the utility pole 10a, and a spiral that is positioned on both sides of the hook portion 31a and is wound around one end portion of the support wire portion 2. Shaped winding portions 32a and 33a. In addition, the winding grip 30b is a hooking portion 31b that can be hooked on the L-shaped metal piece 11b of the utility pole 10b, and a spiral shape that is positioned on both sides of the hooking portion 31b and is wound around the other end portion of the support wire portion 2. Winding portions 32b and 33b.

  Each of the winding grips 30a and 30b is composed of a plurality of hard steel wire rods plated with zinc or zinc / aluminum alloy. Specifically, each of the winding grips 30a and 30b is formed by collecting and bonding a plurality of spirally formed steel wire rods, and twisting and twisting the central portion after drying. That is, the hook portions 31a and 31b are portions twisted and twisted, and are formed into a single wire by twisting a plurality of hard steel wire rods, and are not hollow spirals. On the other hand, the winding portions 32a and 33a of the winding grip 30a are portions that are not twisted and extend spirally around the central axis of the winding grip 30a. The winding portions 32b and 33b of the winding grip 30b are also untwisted portions and extend spirally around the central axis of the winding grip 30b. In addition, a friction increasing material is applied to the inner surfaces of the spiral winding portions 32a, 33a, 32b and 33b of the winding grips 30a and 30b in order to increase the holding force for holding the support wire portion 2 of the drop cable 1. Has been. In FIG. 1 and FIGS. 3 to 8 to be referred to later, the hook portions 31a and 31b are drawn in a single wire for convenience of explanation, but in reality, a structure in which hard steel wire rods are twisted together as described above. have.

Hereinafter, the method for retaining the drop cable 1 according to the present embodiment will be described in detail. FIG. 2 is a flowchart showing a method for retaining the drop cable 1. As shown in FIG. 2, the method for retaining the drop cable 1 according to this embodiment is as follows:
Step S1 for winding the winding grip 30a around one end side of the support wire portion 2 of the drop cable 1,
Step S2 for hooking the hook portion 31a of the winding grip 30a wound around one end side of the support wire portion 2 of the drop cable 1 to the L-shaped metal piece 11a constituting the retaining portion of the utility pole 10a;
Step S3 for marking 4 at the position of the drop cable 1 corresponding to the position of the L-shaped metal piece 11b constituting the retaining portion of the utility pole 10b (the retaining point) in a state where tension is applied to the other end of the drop cable 1.
The tension applied to the other end of the drop cable 1 is once released, and the winding on one side of the winding grip 30b is arranged so that the center position of the hook portion 31b of the winding grip 30b corresponds to the position of the mark 4. Step S4 for winding the attachment portion 32b around the other end side of the support line portion 2 of the drop cable 1,
By hooking the hook portion 31b of the winding grip 30b on the L-shaped metal piece 11b constituting the retaining portion of the utility pole 10b, and applying tension to the winding portion 33b on the other side of the winding grip 30b with the L-shaped metal piece 11b as a fulcrum. Step S5 for adjusting the slackness between the L-shaped metal parts 11a and 11b of the support line portion 2 of the drop cable 1,
Step S6 of winding the winding portion 33b on the other side of the winding grip 30b around the other end side of the supporting wire portion 2 of the drop cable 1 in a state where the slackness of the supporting wire portion 2 of the drop cable 1 is adjusted. Is included.

  Hereinafter, each step shown in FIG. 2 will be described.

  3 shows that the winding portion 32b on one side of the winding grip 30b is positioned so that the center position of the hook portion 31b of the winding grip 30b corresponds to the position of the mark 4 by the above-described step S4. Is shown around the other end of the support wire portion 2 of the drop cable 1. Moreover, FIG. 4 has shown the state which hooked the hook part 31b of the winding grip 30b on the L-shaped metal fitting 11b of the utility pole 10b in step S5 mentioned above. Furthermore, FIG. 5 applies tension to the winding portion 33b on the other side of the winding grip 30b with the L-shaped metal piece 11b as a fulcrum from the state shown in FIG. The adjusted state is shown. Further, FIG. 6 shows a state in which the winding portion 33b on the other side of the winding grip 30b is wound around the other end side of the support wire portion 2 of the drop cable 1 from the state shown in FIG. ing.

  In step S1, the winding portions 32a and 33a of the winding grip 30a are wound around one end side of the support wire portion 2 of the drop cable 1, and an annular hooking portion 31a is formed on one end side of the support wire portion 2 of the drop cable 1. (See FIG. 1).

  In step S2, the annular hook 31a of the winding grip 30a formed in step S1 is hooked on the L-shaped metal part 11a of the utility pole 10a, and one end side of the drop cable 1 is retained on the L-shaped metal object 11a (FIG. 1). reference).

  In step S3, the other end side of the drop cable 1 is tensioned to the point where it can be stretched by the operator's hand, and the position corresponding to the anchor point on the other end side of the drop cable 1 in the support line portion 2 of the drop cable 1 That is, the mark 4 is made at a position that is close to the L-shaped metal piece 11b of the utility pole 10b. In addition, as shown in FIG. 3, as a method of attaching the mark 4, for example, it is possible to attach a mark member such as an adhesive tape that is colored and easily visible from the outside. This step S3 is a step of aligning the position of the other end side of the support line portion 2 of the drop cable 1 in a tensioned state with the position of the anchoring point. It is described as “S3”.

  In step S4, the tension applied to the other end side of the drop cable 1 after marking 4 in the alignment step S3 is once released. Then, the winding portion 32b on one side of the winding grip 30b is connected to the drop cable 1 so that the center position of the hook portion 31b of the winding grip 30b substantially coincides with the position of the mark 4 made in the alignment step S3. It winds around the other end side of the support line part 2 (refer FIG. 3). In the example shown in FIG. 3, the mark 5 is also attached to the center position of the hook portion 31 b by the mark member, as with the mark 4. For convenience of explanation, this step S4 is hereinafter referred to as “step S4 with the first volume”.

  In step S5, the hook portion 31b of the winding grip 30b wound around the other end of the support wire portion 2 in the first winding step S4 is hooked on the L-shaped metal piece 11b of the utility pole 10b (see FIG. 4). The slack of the support wire portion 2 of the drop cable 1 is adjusted by applying tension to the winding portion 33b on the other side of the winding grip 30b with the hardware 11b as a fulcrum (see FIG. 5). Note that the hooking portion 31b of the winding grip 30b in a state where tension is applied to the other end side of the support wire portion 2 of the drop cable 1 by executing the above-described positioning step S3 and first winding step S4. The center position of the winding grip 30b is set to L in step S5 because the center position is fixed at the position of the anchor point (in this embodiment, the position of the L-shaped metal piece 11b of the utility pole 10b) (see FIG. 3). The sag of the support line portion 2 between the utility poles 10a and 10b can be brought to a state close to a desired sag by simply hooking the mold 11b.

  Further, in step S5, the tension in the direction of the thick arrow shown in FIG. 5 is applied to the winding portion 33b on the other side of the winding grip 30b with the hook portion 31b of the winding grip 30b hooked on the L-shaped metal piece 11b. By doing so, the sag of the support wire part 2 can be adjusted to a desired sag. This step S5 is hereinafter referred to as “adjustment step S5” for convenience of explanation. Moreover, although the support wire | line part 2 shown in FIG. 3 may cut | disconnect the part which protruded from the winding grip 30b after said step S4 for length adjustment depending on the form of an installation, FIG. As shown in FIG. 6, in the support line portion 2 of the present embodiment, portions protruding from the winding grips 30 a and 30 b to both sides are left without being cut and are connected to and integrated with the element portion 3 again.

  Here, in the adjustment step S5, the U-shaped winding grip curved at the position of the hook portion may be used as it is. However, in the adjustment step S5 of the present embodiment, the linear winding grip 30b is used. The hooking portion 31b is hooked on the L-shaped metal piece 11b and the other winding portion 33b is tensioned to be bent and deformed. By adjusting the slackness of the support wire portion 2 while bending the winding grip 30b in a linear state at the position of the hooking portion 31b, the slackness is adjusted (see FIG. 6), and the slackness is adjusted by bending deformation. The position of the bent bottom 34 of the formed hook portion 31b is easily coincident with the position of the inner surface of the L-shaped metal piece 11b. Therefore, the work for adjusting the sag is facilitated, and it is possible to make it difficult to generate unintended sag in the support line portion 2. Note that the position of the bent bottom 34 substantially coincides with the center position of the hook portion 31.

  Note that the linear winding grip 30b used in the present embodiment deforms the U-shaped one that is curved at the position of the hooking portion 31b into a linear state before the first winding step S4 described above. (See FIG. 7).

  In addition, since the tension and the sag are proportional to the square of the span length as shown in the above formula (1), if the length of the hook portion 31b of the winding grip 30b is less than 5 cm, the construction of the operator It may be difficult to adjust the sag due to blurring. Therefore, the length of the hook portion 31b of the winding grip 30b is preferably 5 cm or more.

Furthermore, if the hard steel wire constituting the winding grip 30b is too thick, it is difficult to retain it by plastic deformation from a linear state by human power. Here, a winding grip for 10CR used for a suspension wire (hereinafter referred to as “10CR”) having a cross-sectional area of 10 mm ² in which seven hard steel wire rods having a diameter of 1.4 mm are twisted together ( However, in human-powered construction, the use of this 10CR winding grip is the limit in the manual construction. That is, in consideration of workability and workability by human power, it is preferable to use a winding grip 30b having a rigidity smaller than that of the 10CR winding grip. Further, when using such a winding grip 30b, the supporting wire diameter corresponding to the winding grip 30b is not limited to the one of 1.2 mm of this embodiment, and if it is a supporting wire having a cross-sectional area smaller than 10CR, it is drawn. It can be fastened.

  Finally, in step S6, the winding part 33b on the other side of the winding grip 30b is connected to the support line part 2 of the drop cable 1 in a state where the slackness of the support line part 2 of the drop cable 1 is adjusted in the adjustment step S5. (See FIG. 6). Thereby, the drawing work between the utility poles 10a and 10b of the drop cable 1 is completed. This step S6 is hereinafter referred to as “second volume attaching step S6” for convenience of explanation.

  As shown in FIG. 6, the element portion 3 of the drop cable 1 is disposed along the support wire portion 2.

  In the present embodiment, a method of retaining the drop cable 1 between the L-shaped hardware 11a attached to the utility pole 10a and the L-shaped hardware 11b attached to the utility pole 10b using the winding grips 30a and 30b. Although demonstrated, the structure of the support body which hooks the winding grips 30a and 30b and its retention part is not restricted to this. That is, the drop cable 1 can be secured to a building as a support using the same retention method as in the present embodiment. In such a case, a C-shaped hardware attached to the building can be used as the retaining portion of the building. Moreover, it is also possible to hold the drop cable 1 to the suspension line between the utility poles as a support using the same drawing method as this embodiment. In such a case, a segmented hardware attached to the suspension line can be used as the retaining portion of the suspension line.

  As described above, the retaining method according to the present embodiment is not limited to the retaining operation of the drop cable 1 between the two utility poles. For example, the retaining operation of the drop cable 1 between the utility pole and the building, the suspension line and the building It can also be used in the drawing operation of the drop cable 1 between the two.

  Furthermore, the retaining portion of the support is not limited to the above-described L-shaped hardware, C-shaped hardware, and segmented hardware as long as the hooking portion of the winding grip can be hooked. For example, as shown in FIG. 8, the retaining portion of the support is configured by a round thimble 13 that is a hardware different from the above-described hardware attached to the utility pole 10b as a support via a band member 12b. It is also possible to do.

  In the conventional holding using the S-shaped hardware, the support wire portion 2 is plastically deformed while being wound around the S-shaped hardware in a complicated manner (see FIGS. 9 and 10). In some cases, stress was concentrated on the support wire and the support wire was fatigue fractured (see FIG. 11). On the other hand, in this embodiment, since the drop cable 1 is retained using the winding grips 30a and 30b, the support line portion 2 of the drop cable 1 can be gripped without plastic deformation ( 6), local stress concentration can be prevented. Therefore, stress is dispersed and fatigue breakage of the support wire can be suppressed.

  Further, in the conventional retention using the S-shaped hardware, the support cable portion of the drop cable is wound around the S-shaped hardware for a certain length, and therefore an extra length is generated in the element portion having the same length as the support wire portion (FIG. 12). This extra length needs to be processed. On the other hand, in this embodiment, since the winding grips 30a and 30b are used, the retaining line portion and the element portion can be retained in a state in which the length is 1: 1. In other words, in this embodiment, since the winding grips 30a and 30b are used, it is possible to prevent the extra length from occurring in the element portion 3. Therefore, even if the configuration in which the element portion 3 is connected to the support wire portion 2 again at a position outside the winding grips 30a and 30b as in the present embodiment, the extra length of the element portion 3 is unlikely to occur. It can be set as the structure which is hard to generate | occur | produce excessive slack in the element part 3 (refer FIG. 6). Moreover, even if some slack occurs in the element portion 3, the element portion 3 and the winding grips 30a and 30b are connected with an insulating tape 40 such as a polyvinyl chloride (PVC) tape as shown in FIGS. By fixing, the generated slackness can be further reduced or completely eliminated. Therefore, the element part 3 can be prevented from being broken due to crow stagnation or snow accretion, and the reliability as equipment can be improved.

  Furthermore, in the conventional retaining using the S-shaped hardware, when the support wire portion is wound around the S-shaped hardware while plastically deforming, a slight slack occurs and the looseness increases (see FIG. 9). In the present embodiment, since the winding grips 30a and 30b are used for holding, the work of winding the support wire portion 2 in a complicated manner while plastically deforming it becomes unnecessary. Therefore, since the looseness hardly occurs in the support wire portion 2, an increase in the sag is suppressed.

  Note that the dropping method of the drop cable according to the present invention is not limited to the one described in the above-described embodiment, and various modifications can be made without departing from the gist of the invention described in the claims. It is.

  The present invention relates to a drop cable retaining method, and more particularly to a drop cable retaining method using a winding grip.

1: Drop cable 2: Support line part 3: Element part 4, 5: Mark 10a, 10b: Utility pole (support)
11a, 11b: L-shaped hardware (retention part)
12a, 12b: Band member 13: Round thimble (retention part)
30a, 30b: winding grips 31a, 31b: hooking parts 32a, 32b, 33a, 33b: winding part 34: bent bottom 40: insulating tape

Claims (4)

A first winding step of winding a winding portion on one side of a winding grip provided with a hooking portion that can be hooked on a retaining portion of a support and a spiral winding portion located on both sides of the hooking portion. When,
An adjustment step of adjusting the slackness of the drop cable by hooking the hooking portion on the retaining portion and applying tension to the winding portion on the other side of the winding grip with the retaining portion as a fulcrum;
A second winding step of winding the other winding portion around the drop cable in a state in which the sag of the drop cable is adjusted.   In the adjustment step, the winding grip in a linear state is bent and deformed by hooking the hooking portion to the retaining portion and applying tension to the winding portion on the other side. Item 2. The drop cable retaining method according to Item 1. Before the first winding step, the method further includes an alignment step of marking the position of the drop cable corresponding to the position of the retaining portion in a state where tension is applied to the drop cable,
In the first winding step, winding the winding portion on the one side around the drop cable so that the center position of the hooking portion of the winding grip corresponds to the position of the mark. The method for retaining a drop cable according to claim 1 or 2, characterized in that   The drop cable retaining method according to any one of claims 1 to 3, wherein the retaining portion is made of a hardware attached to a support.