JP3370779B2 - Cable tension detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable tension detecting device, and more particularly to a tension detecting device suitable for pulling and laying an optical fiber cable or the like.

[0002]

2. Description of the Related Art Conventionally, when laying a long optical fiber cable in a pipeline such as underground, an automatic laying method by a tension control system has been adopted. That is, as shown in FIG. 2, a plurality of manholes 2 arranged along the pipeline 1.
A cable 5 to be extended by a tension detecting device 4 which is installed inside each of the laying devices (electric caterpillar type feeding device) 3 and is inserted into one outlet of each laying device 3
Of the laying device 3 is controlled so that the detected value becomes a preset tension value, and a plurality of laying devices are laid in synchronization with the feeding speed of the laying device 3 in front. A method of interlocking the device 3 is adopted.

In such an automatic laying method, a cable tension detecting device 4 having the following structure is used. That is, in the tension detecting device 4, as shown in FIGS. 3 and 4, the load cell 6 which is a device for detecting an applied load or force by utilizing a phenomenon such as piezoelectricity or electromagnetic induction is The load member, which is the central axis of the detection unit 8, is attached downward to the support member 7 held by, and the cable guide 9 is directly attached to the detection unit 8 of the load cell 6. The cable guide 9 includes a U-shaped mounting guide member 10,
It consists of a group of guide rolls 11 surrounding the cable passage and arranged in three directions so that each roll axis forms 60 °. The guide rolls 11 are at the lower end of the mounting guide member 10 and the uppermost guide roll 11a. Mounted so that the shaft is horizontal. Then, the cable 12 is passed through the cable passage surrounded by these guide rolls 11.
When the cable is laid, the vertical component f (f = 2F sin θ) is applied upward to the detecting portion 8 of the load cell 6 by the tension F acting in the cable extending direction, and this f is detected by the load cell 6. It is like this. Note that θ is
The inclination angle (intersection angle) of the cable 12 to be extended is shown with respect to the horizontal.

[0004]

However, in such a conventional cable tension detecting device, the cable tension F is
Since the cable guide 9 for loading the vertically upward component f of the load cell 6 is directly attached to the detection portion 8 of the load cell 6, when the cable 12 passes between the guide rolls 11, the cable 12 is connected to the tow rope. Parts (connection fittings, etc.)
When the load is caught, a moment of bending or twisting or an impact force acts on the detecting portion 8 of the load cell 6, and the detecting portion 8
Could be damaged.

The present invention has been made in order to solve such a problem, and in a tension detecting device used for laying a cable such as an optical fiber cable, a cable end or the like is caught when passing through the cable guide. An object of the present invention is to provide a cable tension detecting device in which the load detector is not likely to be damaged even if the above occurs.

[0006]

The cable tension detecting device of the present invention is configured to detect a vertically upward component of the tension of a cable to be laid by a load detector via a cable guide. In the cable tension detecting device, the cable guide is attached to a fixing member so as to be swingable around a horizontal axis orthogonal to the extending direction of the cable without being connected to the detecting portion of the load detector. The vertically upward component of the cable tension converted into the oscillating motion of the cable is applied to the detecting section through the oscillating motion, and the horizontal axis of the cable guide is pinched.
Cable to the end opposite to the load side of the cable tension.
Attach a coil spring that elastically urges in the direction
Due to the resilience of the il spring, the cable guide
The moment about the horizontal axis is set to substantially zero .

[0007]

In the tension detecting device of the present invention, the cable guide is not directly connected to the detecting portion of the load detector, but is swingable about the horizontal axis orthogonal to the extending direction of the cable. , Is attached to another fixing member. Therefore, even if the metal fittings of the cable connection part get caught when passing through the cable guide, the moment of bending or twisting, impact force, etc. do not act on the detection part of the load detector, and the load detection The vessel is not damaged. Then, the vertically upward component of the cable tension to be laid is converted into the swinging movement of the cable guide without being applied to the detecting portion of the load detector as it is, and such swinging movement of the cable guide is prevented. The load is applied to the detection unit via.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing an embodiment of the cable tension detecting device of the present invention.

In the figure, reference numeral 13 indicates a supporting member which is held horizontally, and a load cell 14 is provided on the lower surface of this member.
However, the detector 15 is attached downward so that the central axis (load axis) of the detector 15 is vertical. And this load cell 1
4, an L-shaped attachment member 16 is provided below the support member 13, and a cable guide 17 is provided at the lower end of the attachment member 16 to swing around a horizontal axis orthogonal to the cable extension direction. It is movably attached. That is, the cable guide 17 is composed of an L-shaped mounting guide member 18 and three guide rolls 19 attached to the lower end of the hanging portion so as to surround the cable passage. The support pin 20 is provided in the hole formed at the position.
Is inserted and fitted by the support pin 20 to the lower end of the adjacent mounting member 16 so as to be swingable around the pin 20. The mounting guide member 18 as described above is an end portion of one side of a horizontal portion that is immediately above the attachment position of the group of guide rolls 19 and is the detecting portion 1 of the load cell 14.
5 and the vertically upward component f (f = 2F sin θ) of the tension F of the cable 21 laid through the cable passage between the guide rolls 19 swings around the support pin 20. The detection unit 15 is configured to be loaded via the. Further, a coil spring 23 whose elastic force can be finely adjusted by an adjusting nut 22 is contracted to the other end of the horizontal portion of the attachment guide member 18. The adjusting nut 22 adjusts the elastic force w ₂ of the coil spring 23 so that the moment around the support pin 20 of the cable guide 17 becomes substantially zero. That is, the weight w ₁ of the cable guide 17
Thus, the moment generated around the support pin 20 is offset by adjusting the elastic force w ₂ of the coil spring 23. Further, in the horizontal portion of the attachment guide member 18, the contact portion of the load cell 14 with the detection portion 15 is arranged at the same height as the center of the support pin 20, and the detection portion 15 is connected to the detection portion 15 via the cable guide 17. When the tension applied is zero, the mounting guide member 18
Is configured such that the horizontal portion of the is horizontal.

In the cable tension detecting device of the embodiment configured as described above, the cable guide 17 is not directly connected to the detecting portion 15 of the load cell 14, but is swayed by the support pin 20 to another adjacent mounting member 16. Since it is movably attached, only the vertically upward component f of the cable tension F is loaded on the detecting portion 15 of the load cell 14.
Therefore, even if metal fittings or the like of the connecting portion of the cable 21 are caught when passing through the cable guide 17, the moment of bending or twisting, impact force, or the like is different from that of the load cell 14 via the support pin 20. It acts on the member and does not act on the detection unit 15 of the load cell 14.
Further, the horizontal portion of the mounting guide member 18 and the adjusting nut 22
The coil spring 23 is contracted between the
Moreover, by changing the vertical position of the adjusting nut 22 and adjusting the elastic force of the coil spring 23, the moment around the support pin 20 due to the weight of the cable guide 17 becomes substantially zero, so that the cable tension can be detected accurately. It can be carried out. Furthermore, the cable guide 17 and the load cell 1
4 is held at the same height as the center of the support pin 20, and when the cable tension applied through the cable guide 17 is zero, the horizontal portion of the attachment guide member 18 is in a horizontal state. Therefore, the load cell 14 can detect the tension with high accuracy.

In the above-described embodiment, the coil spring 23 is contracted at the end of the attachment guide member 18 of the cable guide 17, and the elastic force of the spring 23 is finely adjusted so that the weight of the cable guide 17 is reduced. Support pin 2 by
Although the moment about 0 is zero, a balance weight may be provided at a similar position instead of the coil spring 23.

[0013]

As described above, according to the apparatus of the present invention, in detecting the tension of a cable such as an optical fiber cable, even if a cable end is caught by the cable guide, the load detector is detected. It is possible to detect tension with high accuracy over a long period of time without being damaged. Therefore, the automatic interlocking installation by controlling the tension of the cable can be performed for a long time without any trouble.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a cable tension detecting device of the present invention.

FIG. 2 is a diagram schematically showing a conventional automatic cable laying method by a tension control system.

FIG. 3 is a front view showing a conventional cable tension detecting device.

FIG. 4 is a side view showing a conventional cable tension detecting device.

[Explanation of symbols]

14 ... Load cell 15 ... Detection unit 16 ... Attachment member 17 ......... Cable guide 18 ... Mounting guide member 19 ……… Guide roll 20 ... Support pins 21 ......... Cable 22 ......... Adjusting nut 23 ... Coil spring

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02G 1/06 JISST file (JOIS)

Claims (4)

(57) [Claims] 1. A cable tension detecting device configured to detect a vertically upward component of the tension of a cable to be laid by a load on a load detector via the cable guide, wherein the cable guide is connected to the load. The vertical direction of the cable tension converted into the swinging motion of the cable guide is attached to the fixing member so as to be swingable around a horizontal axis orthogonal to the extending direction of the cable without being connected to the detecting portion of the detector. The upward component is applied to the detection unit through the swinging motion, and further, the cable guide is elastically urged downward at the end opposite to the load portion of the cable tension with the horizontal axis interposed therebetween. A cable, wherein a biasing coil spring is attached, and the moment about the horizontal axis of the cable guide is made substantially zero by the elastic force of the coil spring. Force detection device. 2. The cable tension detecting device according to claim 1, wherein the coil spring is capable of finely adjusting the elastic urging force. 3. The center of the horizontal shaft portion and the contact portion between the cable guide and the load detector are arranged at the same height, and the cable tension applied to the load detector is vertically upward. The cable tension detection device according to claim 1 or 2, wherein the cable guide is configured to be in a horizontal state when the component is zero. 4. The cable tension detecting device according to claim 1, wherein a detecting portion of the load detector is arranged vertically above the cable guide.