JPH10285771A - Coiled cable hanger made of stranded synthetic resin wire - Google Patents

Abstract

(57) [Summary] PROBLEM TO BE SOLVED: To provide a cable hanger for temporarily supporting a wiring cable at the time of a wiring work in a city such as a communication cable of a cable television, etc., which makes the wiring work safer and more efficient. Providing a cable hanger that allows you to do. SOLUTION: A cable hanger 1 is formed by winding a plurality of extruded and stretched saturated polyester resin wires 3 into a coil shape by twisting a wire 2 formed. The relationship between the twist of the element wire and the winding direction of the coil is such that when the element wire is S-twisted, the winding direction is left-handed, and when the element wire is Z-twisted, the winding direction is right-handed. When using,
The wiring cable and the messenger wire are inserted into the extended coil, and the cable is supported.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work for replacing a metal U-hanger or a lashing rod, which has been conventionally used, for a communication cable such as a cable television and a power cable in a city. An object of the present invention is to provide a coiled cable hanger made of a stranded synthetic resin wire as a coiled continuous cable hanger that can achieve streamlining and efficiency.

[0002]

2. Description of the Related Art Conventionally, when a communication cable or the like for a cable television or the like is laid in the city (extension work), a messenger wire of a hard steel wire stranded wire is first stretched over a telephone pole, and the cable is placed along the wire. It is suspended by a metal U-shaped cable hanger at 60 cm intervals. Alternatively, as another cable hanger, a cable and a messenger wire are wound into a single bundle by a lashing rod spiral with a lashing rod (resin-coated steel wire threaded member) having a length of about 70 cm.

[0003]

However, these works must be manually stopped one by one using a high-altitude work vehicle, which poses a serious problem in terms of worker safety and workability. ing. An object of the present invention is to provide a coil-shaped continuous cable hanger (hereinafter, simply referred to as a coil hanger) that enables wire drawing work with high working efficiency, instead of the conventional U-shaped cable hanger and lashing rod.

[0004]

SUMMARY OF THE INVENTION A cable hanger according to the present invention is formed in a coil shape by using a strand of an extruded and stretched saturated polyester resin wire as a strand. The relationship of the winding direction is as follows.
It is preferable that the winding direction of the coil is left-handed when the wire is a twisted wire, and that the coil is wound rightward when the wire is a twisted wire. Further, the twist pitch of the strand is desirably 2 to 4 times in a spring index ratio (twist pitch / spring index). In some cases, a metal wire may be twisted at the center of the strand.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a concrete method of using the coil hanger, first, when a messenger wire is laid between utility poles, a coil hanger having a length corresponding to the utility pole is prepared in advance, and the coil hanger is passed therethrough. Connect the messenger wire. Next, one end of the coil hanger is fixed to the messenger wire near one utility pole, and then the other end is pulled to spread the coil and fixed near the other utility pole. Finally, the cable is pulled in with a lead rope or the like that has been passed through the coil hanger in advance. Since the cable can be pulled in for about 10 spans at a time, the cable drawing operation for several hundred meters at a time is completed.

[0006] Regarding the lead rope, the messenger wire may be placed through the coil hanger together with the messenger wire when the messenger wire is wired, or when the coil hanger is spread, the tip of the lead rope is attached to the end of the coil to be extended. May be tied together and pulled into the coil hanger together when spreading the coil. When the cable is pulled in, when the coil hanger is spread, the coil end and the tip of the cable are brought together and connected to a lead rope previously passed through the coil hanger and pulled. Or, before spreading the coil hanger, temporarily wire the cable along the messenger wire,
The coil hanger may be spread later. Such improvement in workability significantly improves work efficiency, and further contributes to alleviation of traffic congestion due to the work vehicle occupying the road for a long time.

Next, regarding the coil hanger of the present invention,
First, a method for manufacturing a stranded synthetic resin wire serving as a strand and then a method for manufacturing a coil will be described. As the raw material of the stranded synthetic resin wire of the present invention, a saturated polyester resin wire subjected to extrusion stretching is used. As the saturated polyester resin, polyethylene terephthalate (PET), polyethylene isophthalate, polybutylene terephthalate (PBT), polyethylene terephthalate (PEN)
For example, a saturated polyester resin having stretchability and heat fixability such as the above is used. These resins are resins having good weather resistance among thermoplastic resins, and can withstand long-term outdoor use by stretching and blending of a weather resistance stabilizer. These saturated polyester resins are melt-extruded from a die nozzle at the tip of an extruder, and the extruded filaments are once cooled, then uniaxially heated and stretched and wound around a bobbin.

Next, the bobbin can be manufactured by attaching the bobbin to a strander (rope twisting machine) or a cage type twisting wire machine, and twisting the potential drawn out at a constant payout speed, number of turns, and turning direction. Since the saturated polyester resin wire has plastic deformability, it can be processed into a stranded wire without particularly applying heat. In order to twist a thin metal wire into the center of the strand, the configuration can be easily changed simply by making the core bobbin of the cage type twisting machine a metal wire such as a stainless steel wire.

Next, a core is attached to a device that can be rotated, for example, a lathe, and a stranded wire is attached to the rotated core by an S wire.
In the case of twisting, the winding direction is left-handed. When the strand is Z-twisted, the winding direction is right-handed and closely wound in a line. The twistable material can be supplied at a certain angle to the pipe by a movable guide. Subsequently, the core is heated together with the core metal in a hot-air heating tank with both ends fixed, then cooled with water to fix the shape, and the core metal is removed to form a coil hanger. Here, since the extruded and stretched saturated polyester resin wire has a property of being thermally shrunk when heated, when it is made into a stranded wire and heated in a tensioned state, the cross sections of the stranded wire constituting the stranded wire are deformed to be in close contact with each other. Specifically, in the case of a three-stranded wire, the wires are in close contact with each other as shown in FIGS. In addition, when a metal wire is inserted in the center, the state becomes as shown in FIGS.

[0010] The coil hanger of the present invention is, for example, a left-handed three-strand S-twist having a wire diameter of 6 mm (3 mm x 3 strands), a coil diameter of 82 mm, and a strand pitch of 40 mm (spring exponent ratio 2.9). When it is stretched to a pitch of 150 mm using a coil hanger, a spiral having an inner diameter of 60 mm is formed. The force required to expand the coil at that time is 2kgf
Because it is around, it can be easily stretched by hand. Also, the weight of the cable is the case of a CATV coaxial cable.
0.22k even for 12C cable with outer diameter of 12.7mm
Since the weight is as low as g / m, the load resistance of the coil hanger has no problem. Next, regarding the resistance applied when the cable is pulled into the coil hanger, since the inner surface of the coil hanger has a stranded wire shape, the contact surface is small and it is easy to slip and the drawing operation is easy.

Further, as shown in FIG. 9, the coil hanger according to the present invention has a messenger wire and a cable passing through the coil, but there is a gap in the coil. In such a case, in the conventional cable hanger, it was necessary to temporarily remove the cable hanger and perform additional wiring. However, in the case of the coil hanger, there is a merit that an additional cable can be easily provided by feeding an additional cable into a gap between the coils. Here, if the coil hanger is cut for any reason, if the coil hanger returns to the original tight winding, there is a concern that the cable may hang down between utility poles. However, the coil hanger of the present invention is stretched,
When placed for a long time, the strain is relaxed and the original tight wound state cannot be returned. Therefore, for example, when one part is cut off in an accident, it is convenient that the cable does not droop immediately. As an accelerated test, the coil hanger was stretched to a pitch of 150 mm to fix both ends at 200 ° C.
After heating for a time and removing the fixing after cooling, the pitch did not shrink to 130 mm or less under no load.

Next, by changing the color of one or two of the wires constituting the strands of the coil hanger from the others, the cable hanger has a striped pattern, and a danger display or a caution display is displayed. The protection material can be used also. Specifically, when the strands are three or seven strands, one or two of the wires constituting the strands are black,
By making the others yellow, the strands can be made to stand out in a zebra pattern. In many cases, the cable hanger itself becomes a danger display or a caution display, and the cable of the city wiring, which can also serve as a protective material for the cable, often has to pass through a branch of a street tree or a standing tree in a garden. The cable is generally inconspicuous because it is a black resin-coated wire, and great care must be taken when cutting off and pruning tree branches. When the cable is hung by the cable hanger of the zebra pattern according to the present invention, the cable is noticeable, so that the pruning operation is also easy.

[0013] Further, if a fire or the like occurs in a building and the cable runs near the building and the flame reaches the cable, even if the cable hanger is composed only of synthetic resin strands. If it is melted, it may be burnt and cut. If the cable hanger disappears, the cable will hang between the utility poles. Therefore, by twisting a metal wire into the center of the stranded wire, even if the synthetic resin wire portion is burned, the metal wire remains and only the hanging of the cable can be prevented. First, specifically, in the case of seven strands, only the core wire was made of the same diameter stainless steel wire. Since the core was twisted in a straight line in the middle of the seven strands, it could be easily manufactured with a basket-type stranding machine regardless of the difference in bending hardness from the synthetic resin wire. There was no problem in processing into a coil, and there was no particular change in form stability as a cable hanger because the torsional stress was related to the twist pitch and twist direction of the surrounding wires rather than the core wire.

In the case of a three-stranded wire, when the wire constituting the stranded wire is, for example, 3 mm, the center of the three stranded wires is
There is a space for a 0.46 mm line. Therefore, a coil hanger in which a metal wire is twisted at the center of the strand can be produced by twisting the core wire there. Here, since the extruded and stretched saturated polyester resin wire has a property of being thermally shrunk when heated, when it is made into a stranded wire and heated in a tensioned state, the cross sections of the stranded wire constituting the stranded wire are deformed to be in close contact with each other. Specifically, in the case of a three-stranded wire having a metal wire at the center, the state is changed from FIG. 5 before heating to FIG. 6 after heating. Therefore, the thickness of the core wire does not need to be exactly 0.46 mm, and the coil hanger in which the metal wire is twisted at the center of the strand is free from twist unevenness if it is not more than about 1/3 of the wire constituting the twisted wire. Can be made. In fact, when a coil was made by twisting a thin stainless wire of 0.6 mm at the center of a 3 mm × 3 twisted wire, the cross section of the wire became as shown in FIG.

[0015]

EXAMPLES The production examples will be described more specifically. A polyethylene terephthalate resin having an intrinsic viscosity (IV value) of 1.02 is melt-extruded from a nozzle at the tip of an extruder having a circular cross-sectional shape having a diameter of 8 mm, and cooled in a cooling water bath. Solidified φ
A 6.7 mm unstretched filament was introduced into a hot air circulation heating stretching tank, heated to 90 to 120 ° C. at the material surface temperature, stretched to a stretching ratio of 5.0, and then water-cooled in a cooling water tank. After that, it is taken up by a bobbin take-up machine.
Was obtained. Similarly, a plurality of bobbins were prepared. Next, the three bobbins were attached to a cage type twisting machine, and a take-up speed of 5 m / min. , Number of turns 125 rp
m, the wire drawn out while turning clockwise in the turning direction,
Then, it wound tightly in a left-handed left-handed line in a row on a φ76.2 mm steel pipe pipe attached to a lathe. In this case, the stranded wire can be supplied at right angles to the pipe by a movable guide. Subsequently, the steel pipe core pipe is heated together with the steel pipe core pipe in a hot-air heating tank at a temperature of 150 ° C. for 30 minutes in a state where both ends of the coil are fixed, and then water-cooled to fix the shape. Created. The coil is
Wire diameter 6mm (3mm x 3 strands), coil diameter 82m
m, a three-stranded (S-twisted) left-handed coil having a strand pitch of 40 mm (spring exponent ratio of 2.9) was obtained.

[0016]

[Test Example] Table 1 below shows the measurement results of the coil pitch and the tensile tension when the coil was specifically extended before and after the acceleration test. Specimen: 3-strand S-twisted left-handed coil hanger Elementary wire diameter 6 mm (3 mm x 3 strands), coil diameter 82 m
m, strand twist pitch 40mm (spring index ratio 2.9)

As can be seen from the upper part of Table 1, the tension of the coil hanger increases as the coil hanger is spread from the tightly wound state. And the normal use range coil pitch 15
If it exceeds 0 to 175 mm, the resistance increases more rapidly. This property greatly affects the pitch unevenness when the coil hanger is applied and thereafter. In other words, if the tension at the time of tensioning the coil is too large, there is a problem in workability, and if it is too small, if a part is caught at one place, it will be extended there. Also, after construction, if there is no resistance, there is a concern that the pitch may shift when the cable load is uneven. At a minimum, a tension exceeding the frictional resistance with the cable is required. Next, when examining the coil pitch and tension of the lower heating acceleration test sample, it seems that the tension in the construction state is almost gone, but if you try to widen the pitch a little, the tension rises sharply and resists . Therefore, even after the construction, the coil pitch does not change even if the cable is shaken by wind or vibration. The property that it is easy and does not cause pitch unevenness at the time of this construction is a great advantage as a cable hanger.

Further, as a required characteristic of the cable hanger, it is necessary to directly spread the coil hanger without twisting or rotating with respect to the form stability of the coil when the coil hanger is extended during the wire drawing operation. When the coil hanger is stretched and spread, if the end of the coil rotates, the lead rope or cable tied to it will become entangled with the messenger wire and cannot be spread.
Generally, when a coil is largely extended, the tensile stress acts as a torsion stress for twisting the wire and a bending stress for bending the wire inward because the coil is curved inward. . With the balance between the bending stress and the torsion stress, for example, in the case of a general single-wire coil, the torsion resistance is weak, so that the wire is reduced in diameter while rotating in the winding direction. However, as in the coil hanger of the present invention, the twisting resistance of the wire is increased by adjusting the twist pitch of the wire, and by canceling the twisting force, the wire turns only inside the coil and the rotation of the coil end is prevented. Was eliminated.

Specifically, the wire diameter of the present invention is 6 mm (3 mm).
× 3 twisted coil hanger (twist pitch 35mm,
An S-twisted left-handed coil having a coil diameter of 82 mm) and a left-handed tightly wound coil having a circular wire in cross section will be described in comparison. First, when the former coil hanger is stretched, bending stress and one time per pitch are applied to the wire. A torsional stress acts to increase the twist in proportion. The torsional stress in the direction of increasing the twist is defeated by the tensile resistance of the wire constituting the twisted wire (the synthetic resin wire of the present invention has a large tensile elastic modulus because it is stretched), and the pitch of the coil ends without rotating. spread. However, when the left-handed close-coil coil of the comparative example having a circular cross section is stretched, the coil end rotates clockwise (in the direction in which the coil is wound) and the inner diameter of the coil decreases as the pitch increases.

The coil hanger of the present invention and a coil having the same strand but opposite in the winding direction of the coil will be described. A coil having a strand diameter of 6 mm (3 mm × 3 strands) (twist pitch 35 mm, coil diameter 82 mm) In the case of the S-twisted right-handed coil of (1), the torsion resistance of the strand is weak because the torsion stress of the strand acts in the direction to untwist. Also, since the tensile resistance is in the direction of untwisting the twist, it is not applied. Therefore, the coil end rotates largely as in the case of the single wire. Also, S
In the case of a twisted right-handed coil, the effect of the size of the twist pitch is small. Tables 2 and 3 show a comparison of the characteristics of samples manufactured under different conditions with respect to the relationship between the twist pitch and the rotation of the coil end.

As described above, according to the present invention, the twist of the coil end is reduced by applying a twist in a certain direction to the strand in advance so as to cancel the force for rotating the coil end. did it. Since the force is greater as the twist pitch is finer, it has been found that the rotation of the coil end can be controlled by appropriately selecting the twist pitch and direction. The twist direction is S twist for the left-handed coil and Z twist for the right-handed coil. However, if the twist pitch is too small, kink is generated in the strand at the stage of twisting the strand. A preferred twist pitch of the strand is 2 to 4 times the spring index ratio. Spring index is the value of twist pitch divided by spring index. The spring index is a value obtained by dividing the average coil diameter by the element wire diameter.

[0022]

As described above, the coil hanger of the present invention forms a stranded wire in consideration of the twist direction and the twist pitch of the strand, and when the strand is S-twisted, the winding direction is left-handed. Alternatively, when the element wire is Z-twisted, the coil can be easily formed by forming the coil so that the winding direction is right-handed and then heat-fixing. Then, by using the coil manufactured as described above as a cable hanger, it is possible to rationalize and improve efficiency of communication cables such as a cable television and power cable construction in the city. Measurement method: coil pitch is 150 for samples 1-3, 5, and 6
mm, 4 and 7, a weight was suspended from the end of the sample so as to be 270 mm, and the rotation angle of the coil end face per pitch was measured. Winding direction (+), rewinding direction (-)

[Brief description of the drawings]

FIG. 1 shows an example of a three-twisted coil (Z
FIG.

FIG. 2 shows an example (S) of a three-stranded coil according to the present invention.
FIG.

FIG. 3 is a partially enlarged view of a strand of the coil shown in FIG. 1;

FIG. 4 is a partially enlarged view of a strand of the coil shown in FIG. 2;

FIG. 5 is a cross-sectional view (before heating) of an example of a three-stranded wire containing a metal core wire according to the present invention.

FIG. 6 is a cross-sectional view (after heating) of an example of a three-stranded wire containing a metal core wire according to the present invention.

FIG. 7 is a cross-sectional view (before heating) of an example of a seven-stranded wire containing a metal core wire according to the present invention.

FIG. 8 is a cross-sectional view (after heating) of an example of a seven-stranded wire containing a metal core wire according to the present invention.

FIG. 9 is a schematic diagram showing the construction of a coiled cable hanger according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coiled cable hanger 2 Element wire (of coil) 3 Wire material (constituting element wire) 4 Metal core wire 5 Messenger wire 6 Cable

Claims (6)

[Claims] 1. A cable hanger formed into a coil by using a stranded wire of a saturated polyester resin wire subjected to extrusion stretching. 2. The coiled cable hanger according to claim 1, wherein the wire is an S-twisted wire, and a winding direction of the coil is left-handed. 3. The coiled cable hanger according to claim 1, wherein the wire is a Z-twisted wire, and the winding direction of the coil is right-handed. 4. The twist pitch of the strand is 2 to 4 times in a spring index ratio (twist pitch / spring index).
A coiled cable hanger according to claim 3. 5. The coiled cable hanger according to claim 1, wherein two or less of the plurality of wires constituting the strand have different colors from other wires. 6. The coiled cable hanger according to claim 1, wherein a metal wire is twisted around the center of the strand.