JPH0419774B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a clamp used for installing an optical fiber composite overhead ground wire or an overhead cable such as a power transmission line on a steel tower.

(Prior Art) An optical fiber composite overhead ground wire is constructed by passing an optical fiber unit through a normal ground wire while protecting it with a protection pipe made of aluminum or the like. Therefore, when clamping this optical fiber composite overhead ground wire on a steel tower,
If the protective pipe is locally significantly deformed, this will crush the optical fiber unit. in this case,
This increases the optical transmission loss of the optical fiber unit, and makes it difficult to insert and remove the optical fiber unit into the protective pipe when replacing it. or,
Since power transmission lines are constructed of steel-core aluminum stranded wires with aluminum wires twisted around a steel core, if these steel-core aluminum strands are locally deformed significantly,
The aluminum wire is unfavorably damaged.

By the way, as shown in FIGS. 2 to 4, conventional clamps usually have a plurality of clamp holders 2 arranged in alternately opposite directions on a clamp body 1, and pins 3 and 4 are arranged in opposite directions.
The clamp body 2 is pivotally attached to the clamp body 1, and the clamp body 2 is rotated toward the clamp body 1 by the bolts 5 attached to the pins 3 and 4 and the nut 6 screwed thereto. Generally, the overhead cable 7 is clamped between the wire groove 1a of the clamp holder 1 and the wire groove 2a of the clamp holder 2.

(Problems to be Solved by the Invention) However, in the case of a _conventional clamp, as shown in _FIG . That is, the clamp holder pivot point, that is, the pin ₃ , is located within a plane H that is perpendicular to the direction F in which the bolt 5 and nut 6 urge the clamp holder 2 toward the clamp body 1 and passes through the cable center O1. This caused the following problems.

That is, in this case, the cable pressing force P by the clamp holder 2 is applied to the outer circumferential surface of the cable 7 at a point b that is far away from the intersection a of the line V that is parallel to the urging direction F and passes through the center _O1 and the outer circumferential surface of the cable. As a result, the inclination angle Θ of the pressing force P with respect to the line V increases. Then, in opposition to this pressing force P, the cable 7
The distribution of reaction force exerted on line groove 1 is as shown by Q.
The reaction force also applies to the part of the cable 7 that has come off from a.
Therefore, when the conventional clamp clamps the cable 7, the cable 7 is locally protruded and deformed to a large extent in the portion away from the wire groove 1a.

When the cable 7 is an optical fiber composite overhead ground wire, this protruding deformation causes the internal protection pipe to be locally deformed significantly at the same location, and the concomitant crushing of the optical fiber unit causes the damage to occur. This may increase optical transmission loss, make it difficult to insert or remove the protective pipe when replacing the optical fiber unit, and cause the cable 7
If it is a steel core aluminum stranded wire, it will damage the aluminum wire.

(Means for Solving the Problems) The present invention solves the above-mentioned problems by shifting the pivot point of the clamp, and specifically, the above-mentioned problem is solved by shifting the pivot point of the clamp. A clamp body having a wire groove, and a clamp holder having a wire groove that receives almost the entire opposite half circumference of the overhead cable, and one end of the clamp holder is attached to the clamp body. In a clamp that is directly pivoted and clamps an overhead cable between opposing wire grooves of the clamp body and the clamp body by urging the other end of the clamp body in the direction toward the clamp body, the clamp is attached to the clamp body. Move the pivot point of the presser foot a distance from a plane that is perpendicular to the biasing direction and passes through the center of the overhead cable so that the distribution of the pressing reaction force of the overhead cable is contained within the wire groove of the clamp body. The configuration is shifted to the side of .

(Function) According to this configuration, the cable pressing force by the clamp holder acts on the outer circumferential surface of the cable near the point directly opposite to the middle of the wire groove in the circumferential direction of the clamp body, and the cable is pressed so as to oppose the pressing force. The distribution of the reaction force exerted by the clamp body can be contained within the wire groove of the clamp body, and the cable can be prevented from being deformed by protruding.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of the clamp of the present invention, in which the same parts as in FIG. 4 are designated by the same reference numerals.

In the present invention, a pair of protruding ears 1b extending toward the clamp body 1 are integrally provided, and the end of the clamp presser 2 is pivotally connected between these protruding ears via a pin 3. , the pivot point (pin 3) of the clamp presser foot 2 with respect to the clamp body 1
is perpendicular to the biasing direction F and the center of the cable 7
Shift it toward the clamp presser 2 by δ from the plane H passing through _O1 .

Such a clamp is also used in the same manner as described above with reference to FIGS. 2 to 4, and is used to clamp the overhead cable 7 and install it on a steel tower (not shown).

During this clamping, the cable pressing force P by the clamp holder 2 is applied at a point b ₁ which is very close to the intersection a of the line V that is parallel to the clamp holder biasing direction F and passes through the cable center O ₁ and the outer peripheral surface of the ground wire. The inclination angle Θ ₁ of the pressing force P acting on the outer peripheral surface of the cable 7 and against the line V
can be made significantly smaller. Therefore, the distribution of the reaction force exerted on the cable 7 in opposition to the pressing force P is as shown by Q ₁ and falls within the wire groove 1a.
Therefore, the protruding deformation of the cable 7 due to the reaction force is reliably prevented by the wire groove 1a, and when the cable 7 is an optical fiber composite overhead ground wire, the protective pipe is locally greatly deformed and the optical fiber unit is No more crushing. Further, it is possible to solve the problem that the optical fiber unit suffers a large optical transmission loss due to this crushing, and that it becomes difficult to insert and remove the optical fiber unit from the protection pipe when replacing the optical fiber unit.
Further, when the cable 7 is made of steel-core aluminum stranded wire, the aluminum wire can be prevented from being damaged.

(Effects of the Invention) Thus, the clamp of the present invention can be easily fixed by simply shifting the clamp pivot point 3 as described above.
As described above, the distribution Q ₁ of the reaction force exerted on the cable 7 during clamping can be contained within the wire groove 1a without increasing the number of parts, and local deformation of the cable 7 can be prevented. Therefore, if the cable 7 is an optical fiber composite overhead ground wire, it is possible to prevent large local deformation of the internal protection pipe, and avoid the trouble of crushing the optical fiber unit in the protection pipe, and the cable When 7 is a steel-core aluminum stranded wire, the aluminum wire can be prevented from being damaged.

Furthermore, for the above-mentioned reasons, it is not necessary to arrange the clamp holders 2 alternately in opposite directions as shown in FIGS. 2 and 3, and these clamp holders can be arranged in exactly the same direction. An additional advantage may also be provided which may facilitate the clamping operation and therefore the erection operation of the cable 7.

[Brief explanation of drawings]

FIG. 1 shows a fourth embodiment of the clamp of the present invention.
2 is a plan view showing a conventional clamp, 3 is a front view of the same clamp, 4
The figure is a longitudinal sectional side view of the clamp taken along the - line in FIG. 3. 1... Clamp body, 1a, 2a... Opposing line groove, 1b... Clamp presser pivoting prong, 2... Clamp presser, 3... Pin (clamp presser pivot point),
4...pin, 5...bolt, 6...nut, 7...
...Aerial cable, F...Clamp presser biasing direction,
H... surface, P... cable pressing force, Θ ₁ ... angle of inclination, Q ₁ ... reaction force distribution, δ... clamp pivot point deviation amount.

Claims (1)

[Claims] 1. One clamp body with a wire groove that receives the overhead cable over almost a semi-circumference, and one clamp holder with a wire groove that receives almost the entire opposing half-circumference of the overhead cable. One end of the clamp holder is directly pivoted to the clamp body, and the other end of the clamp holder is biased in the direction toward the clamp body, thereby gripping the overhead cable between the opposing line grooves of the clamp body and the clamp holder. In the clamp, the pivot point of the clamp presser with respect to the clamp body is set such that the pivot point of the clamp presser with respect to the clamp body is set to
A clamp for an overhead cable, characterized in that the overhead cable is shifted toward the clamp holder by a distance such that the distribution of the pressing reaction force of the overhead cable is contained within the wire groove of the clamp body.