JP2015034771A - Cable tension measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tension measuring instrument which is capable of extending a cable by using not a special winch in which a tension measuring function is incorporated but a normal winch, which is improved in measuring accuracy, which is easy to handle, and which is excellent in operability.SOLUTION: A tension measuring instrument includes: a pair of locking means (121A, 121B) disposed in both ends in an axial direction; a load sensor (119) for detecting a load in a tensile direction acting on the pair of locking means; radio communication means capable of transmitting a measurement value measured by the load sensor to an external device; power supply means (132) for applying an operating voltages of the load sensor and the radio communication means; and a casing in which the load sensor, radio transmission means and power supply means are incorporated. The casing has skeletons (111A, 111B, 114) consisting of metallic materials and outer shells (112A, 112B, 113) consisting of composite materials.

Description

  The present invention relates to a cable tension measuring device, and more particularly to a tension measuring device effective for use in extending a power transmission cable.

  Conventionally, when extending an optical fiber cable for communication, in order to prevent the cable from being broken or damaged due to a tension exceeding a predetermined level, the cable between the cable to be extended and a rope to which the cable is pulled is used. A technique is known in which a cable is extended by winding a tow rope with a winch while monitoring the tension with a tension measuring instrument interposed therebetween. Various tension measuring instruments for use in such work have been proposed (Patent Documents 1 and 2).

  On the other hand, in the field of railways, there are cases where an extra-high cable for power transmission of tens of thousands of volts is extended into a pipeline buried in the ground. When extending an extra-high cable in a pipe buried in the ground, if an ordinary tension measuring instrument that allows the operator to visually read the measured value is interposed between the rope to be pulled and the cable, the tension measuring instrument The measurement value cannot be read directly because of entering the pipe. In addition, since the extra high cable has a tension of several tons when it is extended, a normal tension measuring device lacks the strength. For this reason, it has been common to use a special winch equipped with a tension measuring function.

  However, in the case of a winch equipped with a tension measuring function, the tow rope bends due to the installation position of the winch, etc., and the direction of the tension acting on the cable and the tension acting on the tow rope just before the winch are caused by this bend. In some cases, there was a deviation in the direction, making it impossible to accurately measure the tension.

Japanese Patent Laid-Open No. 10-309011 JP-A-11-287722

  In order to enable the work of extending an extra-high cable using an ordinary inexpensive winch without using an expensive winch having a tension measuring function, the present inventors A tension measuring instrument equipped with a wireless transmitter was examined as a tension measuring instrument interposed between the tow ropes.

  As a result, the extra-high cable is subject to several tons of tension, so the measuring instrument housing must be strong and strong, and the pipe that extends the extra-high cable is buried in the ground. Therefore, it is necessary to make it waterproof because rainwater or the like may accumulate. In particular, the underground conduits on the limited land along the railroad track have narrow and bent parts, so that the length of the measuring instrument is not as long as the tension measuring instrument described in Patent Documents 1 and 2. If the shape is larger than the diameter, it cannot pass through the bent part of the pipeline. Furthermore, it has become clear that there are many limitations compared to tension measuring instruments used when extending optical fiber cables, such as the need to be lightweight to increase measurement accuracy and facilitate handling. It was.

An object of the present invention is to provide a high-strength tension measuring device capable of extending a cable using a normal winch instead of a special winch having a built-in tension measuring function.
Another object of the present invention is to provide a tension measuring instrument that improves measurement accuracy and is easy to handle and excellent in workability.
Still another object of the present invention is to provide a tension measuring instrument that can easily extend a cable inside even a pipe having a bent portion embedded in the ground.

In order to achieve the above object, the present invention
A pair of locking means provided at both ends in the axial direction, a load sensor for detecting a load in the tensile direction acting on the pair of locking means, and a measurement value measured by the load sensor can be transmitted to an external device. In a cable tension measuring instrument comprising: wireless communication means; power supply means for providing an operating voltage of the load sensor and the wireless communication means; and a housing incorporating the load sensor, wireless transmission means, and power supply means.
The casing has a structure having a skeleton made of a metal material and an outer shell made of a nonmetallic material having wear resistance.

  If the tension measuring instrument as described above is used, the cable can be extended using a normal winch instead of a special winch with a built-in tension measuring function, and the tension measuring instrument always has a force in the pulling direction. Since it acts, the measurement accuracy can be increased. In addition, since the tension measuring device having the above structure has a skeleton made of a metal material, it can withstand a large tension when a cable is extended, and it has an outer shell made of a composite material. Even if it is a narrow pipe line buried in the ground and has excellent wear resistance, it can reduce damage even if it is used when extending a cable inside. In addition, since the structure has a high-strength metal skeleton and an outer shell made of a nonmetallic material having wear resistance, the weight can be reduced while ensuring the strength and wear resistance.

Preferably, the skeleton includes a pair of metal base plates arranged to face each other, and a plurality of connecting rods connecting the pair of base plates.
The outer shell includes a pair of dome-shaped cover members joined to the outer side surfaces of the pair of base plates, and a cylindrical body member that contains the plurality of connecting rods or is formed so as to surround the outside. Configure.
As a result, a housing having a high strength skeleton and an outer shell having high wear resistance can be realized with a relatively simple structure. Further, by configuring the dome-shaped cover member to be detachable from the plate, it can be easily replaced when the cover member is worn or damaged.

Further, desirably, a sealing member is interposed between the pair of base plates and the cylindrical body member.
As a result, it is possible to prevent water from entering the inside of the housing in which the load sensor and the wireless communication means are disposed by the seal member, so that the rainwater may be accumulated in the pipeline embedded in the ground. However, the cable can be extended without causing any trouble.

Preferably, the wireless communication means includes an on / off switch provided at a portion facing the inner wall surface of the cylindrical body member, and the cylindrical body member has an opening at a portion corresponding to the switch. And a lid member mounted so that the opening can be opened.
According to this configuration, since the switch is turned off at the work preparation stage and the switch is turned on immediately before the start of towing, power consumption by the wireless communication means can be minimized. The replacement frequency can be reduced.

Desirably, the casing has a cylindrical shape with rounded ends at both ends, and the axial length thereof is set to be larger than the diameter and smaller than twice the diameter.
Thereby, since the rotation radius at the time of changing the direction can be small, the cable can be easily extended inside even a pipeline having a narrow and curved portion embedded in the ground.

Furthermore, it is desirable to comprise storage means for storing values measured by the load sensor in time series.
As a result, the tension measurement result can be saved even if communication by the wireless communication means becomes impossible due to the tension measuring instrument entering the pipeline buried underground during cable extension work. It becomes possible to verify work contents and analyze when work fails.

  According to the tension measuring instrument of the present invention, a cable can be extended using a normal winch instead of a special winch with a built-in tension measuring function, and the measurement accuracy can be increased. Further, since the weight can be reduced while ensuring the strength, there is an effect that the handling is easy and the workability is excellent.

The external appearance of one Embodiment of the tension measuring device which concerns on this invention is shown, (A) is a top view, (B) is a side view. It is front sectional drawing which shows the internal structure of the tension measuring device of embodiment of FIG. It is a plane sectional view showing the internal structure of the tension measuring instrument of the embodiment of FIG. It is explanatory drawing which shows the method of extending the extra high cable using the tension measuring device of embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing an external appearance of a tension measuring instrument according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views showing an internal structure of the tension measuring instrument.

  As shown in FIG. 1, the tension measuring device 100 of the present embodiment has a capsule-shaped main body 110 with rounded ends, and protrudes from both ends of the main body 110 to connect to a cable end or a pulling rope. Clevises 121A and 121B as locking means having hook holes for hooking hooks and the like are provided. The main body 110 includes a pair of disc-shaped base plates 111A and 111B arranged to face each other at a predetermined interval, dome-shaped cover members 112A and 112B mounted on the side surfaces of the base plates 11A and 111B, and the base plate 111A. , 111B interposed between the base plates 111A, 111B, the cover members 112A, 112B, and the body member 113.

Since cable tension is transmitted to the clevises 121A and 121B and the base plates 111A and 111B, the clevises 121A and 121B and the base plates 111A and 111B are made of a material having high strength such as stainless steel or carbon steel. Further, since the tension measuring device 100 moves while rubbing against the inner wall of the pipe line extending the cable, the cover members 112A and 112B and the body member 113 are made of FRP (in order to have excellent wear resistance and reduce the weight of the entire device. Fiber reinforced plastic).
In addition, since it is conceivable that water is accumulated in the pipe line extending the cable, it is desirable to take rust prevention measures by plating when the clevis or the base plate is formed of carbon steel.

  Further, in order to increase the strength of the casing, in particular, the body member 113, as shown in FIG. 2, the connecting rod 114 for connecting the base plates 111A and 111B has a predetermined interval (for example, 45 °) along the circumferential direction. A plurality of (e.g., 8) are provided. A screw is formed at one end of each connecting rod 114, and a screw head is formed at the other step. The connecting rod 114 is disposed so as to penetrate the body member 113, but may be disposed so as to be in contact with the inner peripheral surface of the body member 113.

Further, when the tension measuring device 100 of the present embodiment is used when extending a cable in a pipe line having a bent portion, assuming that the length of the main body 110 is L and the diameter is D, D < It is desirable to design so that L <2D.
In this embodiment, assuming that a cable with a diameter of 110 mm is extended in a pipe having a diameter of 150 mm and having a bent portion, the diameter 110 of the main body 110 is 125 mm and the length L is 224 mm. It was. The protruding amount of the clevis 121A and 121B from the main body 110 was 55 mm. In addition, these numerical values are examples, and are not limited to these.

Next, the internal structure of the tension measuring device 100 according to the present embodiment will be described with reference to the cross-sectional views of FIGS. 2 and 3 are views showing a state in which the tension measuring device of FIG. 1 is cut along a vertical plane passing through the center line and a horizontal plane.
As shown in FIG. 2, a planting bolt 111a is provided on the outer side surface (the left side surface in the figure) of the left base plate 111A. A clevis 121A is coupled. Further, the cover member 112A is joined to the outer side surface (left side surface) of the base plate 111A and attached by screws 115a. A through hole through which the planting bolt 111a and the clevis 121A are inserted is formed at the center of the cover member 112A.

A cylindrical portion 111b is formed at the center of the right base plate 111B. The cylindrical portion 111b has a male screw portion 116a at the outer end (right end portion in the drawing) and a female portion at the inner end portion (left end portion in the drawing). A connecting rod 116 having a threaded portion is inserted. The male threaded portion 116a of the coupling rod 116 is screwed into the female threaded portion of the clevis 121B, and the clevis 121B is coupled to the coupling rod 116.
Further, the cover member 112B is joined to the outer side surface (right side surface) of the base plate 111B and attached by screws 115b. A through hole for inserting the end of the coupling rod 116 on the male screw portion 116a side and the clevis 121B is formed at the center of the cover member 112B.

A sealing packing 117 is inserted between the coupling rod 116 and the base plate 111B to prevent water from entering from the outside. Further, an O-ring 118a for sealing is inserted between the base plate 111A and the cover member 112A, and an O-ring 118b is inserted between the base plate 111B and the cover member 112B.
Furthermore, as shown in FIG. 2, between the left base plate 111A and the left end of the coupling rod 116, there are arranged load cells 119 for measuring loads with screws on both the left and right sides. A screw 119a fixed to the left side surface is screwed into a screw hole formed in the base plate 111A. Further, a screw 119b fixed to the right side surface of the load cell 119 is screwed into a female screw portion formed on the connecting rod 116, so that the tension acting on the clevis 121A and 121B can be measured by the load cell 119. ing.

  As shown in FIG. 2, on the inner surface of the left base plate 111A, a CPU (microprocessor) such as a CPU (microprocessor) that calculates a tension measurement value or controls an internal circuit based on a signal from a wireless transmission circuit or a load cell 119 is used. A circuit device 131 equipped with an arithmetic and control unit and a battery box 132 for supplying power are attached. A base plate 111A is provided with an opening for replacing the battery and a screw-type battery box cap 133 for closing the opening. Has been. A plurality of battery boxes 132 and caps 133 may be provided.

  Further, a switch 134 (see FIG. 3) for turning on and off the transmission circuit is provided on the outer surface (upper surface in the figure) of the circuit device 131, and a connecting rod 114 and a trunk member 113 are provided corresponding to the switch. A screw-type switch cap 135 is mounted to block the opening that allows the switch 134 to be operated at a site that does not interfere with the opening. In addition, it is comprised so that waterproofness may be ensured by interposing packing between the heads of the caps 133 and 135 and the edge of the opening.

As described above, the switch 134 for turning on and off the transmission circuit is provided. Since the cable extension operation often takes 4 to 5 hours, the switch is turned off in the preparation stage. This is to reduce battery consumption as much as possible by turning on the switch only from the start to the end of the pulling of the cable by the winch.
In the tension measuring instrument 100 of the present embodiment, the power consumption of the circuit device 131 is greatest when the transmission circuit performs communication. Therefore, the arithmetic and control unit of the circuit device 131 can be configured to perform communication periodically at intervals of several seconds (for example, 10 seconds) by the transmission circuit. Furthermore, in this embodiment, since the main-body part 110 is formed by FPR, the antenna which protrudes outside the housing is not provided.

  Furthermore, since the tension measuring device 100 according to the present embodiment is assumed to be used when a cable is extended in a pipe having a bent portion, wireless communication becomes difficult due to attenuation of radio waves in the pipe. It is expected that. Therefore, the circuit device 131 is equipped with a storage device such as a non-volatile semiconductor memory, and the values measured by the load cell 119 are stored in time series even when communication is interrupted, and stored in the memory after the work is completed. It may be configured such that the data can be read to verify the work, or when the work is unsuccessful, the cause of the failure (for example, the position where the tension is excessive) can be analyzed.

As described above, the tension measuring device 100 according to the present embodiment has a function of measuring and transmitting the tension acting on the cable when the cable is extended, and is therefore not a special winch with a built-in tension measuring function. The winch can be used to extend the cable. Further, since the force in the pulling direction always acts on the tension measuring device, the measurement accuracy can be improved.
At the same time, the tension measuring device 100 of the present embodiment has a strong skeleton structure composed of base plates 111A and 111B formed of a high-strength material such as stainless steel, and a plurality of connecting rods 114 connecting them. The cover member 112A can be measured while withstanding a large tension of several tons applied to the cable, and the surface of the skeleton structure is formed of a material having high wear resistance and light specific gravity such as FRP. , 112B and the cylindrical shell member 113, the structure is covered with an outer shell, which is excellent in durability. Further, since the skeleton structure is covered with the outer shell, the weight can be reduced while maintaining the required strength, and a tension measuring instrument that is easy to handle and excellent in workability can be realized.

Moreover, since the tension measuring device 100 of this embodiment is designed so that D <L <2D, where L is the length of the main body 110 and D is the diameter, the bent portion is buried in the ground. Even in the case of a pipeline having a cable, a cable can be easily extended inside.
That is, in the case of a laterally long tension measuring instrument whose length of the main body is much larger than twice the diameter as disclosed in the cited documents 1 and 2, it is impossible to pass through a pipeline having a bent portion. It is not suitable for the extension of the cable into the pipeline. Although it is described in the cited reference 2 that it can be used when extending a cable in the ground, the tension measuring instrument of the cited reference 2 is a cable even in the ground because of its shape. It is thought that it is assumed to extend linearly.

Next, how to extend the extra high cable using the tension measuring device 100 of the present embodiment will be briefly described.
When extending an extra-high cable into a pipe line, as shown in FIG. 4, a cable drum 20 in which the extra-high cable to be extended is wound and supported rotatably is arranged on one side of the pipe line 10. Then, the extra high cable 21 is pulled out from the cable drum 20. Then, a locking member 25A such as a hook at the end of the connecting rope 24 having the cable twist prevention metal fitting 23 is hooked on the clevis 22 fixed to the tip of the extra high cable 21 and the connecting rope 24 The other locking member 25 </ b> B is hooked on one clevis 121 </ b> A of the tension measuring device 100.

  After that, the hook member at the end of the traction rope 26 that has passed through the pipe line 10 is hooked on the clevis 121B on the opposite side of the tension measuring device 100, and then the switch cap 135 of the tension measuring device 100 is removed and transmitted. The circuit switch 134 is turned on, and then the cap is put on, and the power source of the winch 30 installed on the opposite side of the pipe line 10 is activated to pull the opposite end of the tow rope 26 while winding it. . Thereby, the tension measuring device 100 and the extra high cable 21 are gradually drawn into the pipe 10. The tension measuring device 100 transmits the measured value of the tension by the transmission circuit, and the operator monitors the received measured value while looking at the display of the receiver 40, and the tension cable 21 is applied with a predetermined tension or more. If it is determined that the power source of the winch 30 is stopped, the extension work is interrupted. Thereby, it can avoid that the cable breaks and damages due to excessive tension.

  As described above, the tension measuring device 100 of the present embodiment measures the tension while being interposed between the extra-high cable 21 to be extended and the tow rope 26 pulled by the winch 30. Even when the tow rope 26 is bent by the pulley 27 or the roller, the tension measuring device 100 is always subjected to tension in the longitudinal direction (direction parallel to the central axis), so that the measurement accuracy is improved. be able to. That is, when a cable is extended using a winch having a tension measuring function, the direction of tension acting on the cable and the force acting on the tension measuring instrument inside the winch when the tow rope is bent by a pulley or roller. Although there is a possibility that the measurement accuracy is lowered due to the direction being shifted, the force is always applied in the same direction as the tension acting on the cable to the tension measuring device of the present embodiment, so that the measurement accuracy is not lowered. .

  Although the invention made by the present inventor has been specifically described based on the embodiment, the present invention is not limited to the embodiment. For example, in the above embodiment, the main body 110 is formed of FPR. However, the main body 110 is made of metal such as stainless steel, and a plurality of holes are formed in the cylindrical wall surface, and a resin plate is formed in the holes. It may be configured to have a structure that achieves wear resistance and light weight by fitting. In the case of this structure, the connecting rod 114 is not necessary.

In the embodiment, the clevis 121A is screwed to the bolt 111a planted on the base plate 111A and the clevis 121B is screwed to the coupling rod 116, and the load cell 119 is interposed between the base plate 111A and the coupling rod 116. However, another connecting rod similar to the connecting rod 116 is provided so as to penetrate the base plate 111A, and the clevis 121A is screwed into the connecting rod, and a load cell 119 is provided between the two connecting rods. It is good also as such a structure.
Furthermore, in the said embodiment, although the trunk | drum member 113 and cover member 112A, 112B which comprise the outer shell of a housing | casing were formed with FRP, it is not limited to FRP, What is necessary is just a nonmetallic material provided with abrasion resistance.

  In the above-described embodiment, the present invention has been described with respect to a tension measuring device suitable for use in extending an extra high cable in a narrow pipe line buried in the ground. However, the present invention can be widely used for a tension measuring instrument used when extending an extra-high cable in the trough and other tension measuring instruments used when extending a cable other than the extra-high cable.

DESCRIPTION OF SYMBOLS 100 Tension measuring instrument 110 Main-body part 111A, 111B Base plate 112A, 112B Cover member 113 Body member 114 Connecting rod 116 Connecting rod 119 Load cell (load sensor)
121A, 121B Clevis 131 Circuit device 132 Battery box 133 Battery box cap 134 Switch for on / off 135 Switch cap 20 Cable drum 21 Extra high cable 22 Clevis 23 Twist prevention bracket 24 Connecting rope 26 Towing rope

Claims (6)

A pair of locking means provided at both ends in the axial direction, a load sensor for detecting a load in the tensile direction acting on the pair of locking means, and a measurement value measured by the load sensor can be transmitted to an external device. A cable tension measuring device comprising: wireless communication means; power supply means for providing an operating voltage of the load sensor and the wireless communication means; and a housing containing the load sensor, wireless transmission means, and power supply means,
The housing is
A cable tension measuring instrument having a structure having a skeleton made of a metal material and an outer shell made of a nonmetallic material having wear resistance. The skeleton includes a pair of metal base plates disposed to face each other, and a plurality of connecting rods that connect the pair of base plates,
The outer shell includes a pair of dome-shaped cover members joined to the outer side surfaces of the pair of base plates, and a cylindrical body member that contains the plurality of connecting rods or is formed so as to surround the outside. The cable tension measuring device according to claim 1, wherein the device is a cable tension measuring device.   The cable tension measuring device according to claim 2, wherein a sealing member is interposed between the pair of base plates and the cylindrical body member.   The wireless communication means includes an on / off switch provided at a portion facing the inner wall surface of the cylindrical body member, and the cylindrical body member has an opening and the opening at a portion corresponding to the switch A cable tension measuring instrument according to any one of claims 1 to 3, wherein a lid member is provided so as to be openable.   The said housing | casing comprises the cylindrical shape which has both ends rounded as a whole, The axial direction length is larger than a diameter and smaller than twice a diameter, The any one of Claims 1-4 characterized by the above-mentioned. Cable tension measuring instrument.   6. The cable tension measuring device according to claim 1, further comprising storage means for storing values measured by the load sensor in time series.

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