JP2554699B2 - How to insert a linear body into a pipe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for inserting a linear body into a pipe, and more particularly to a method for pushing a linear body into a pipe by utilizing vibration.

The present invention is an optical fiber cable in which an optical fiber, a metal wire or other linear body is inserted into a protective tube or a sheath,
Used in the production of electric wires, composite structure pipes, etc.

[Prior Art] It may be necessary to insert a linear body into a long tube or the like. For example, an optical communication cable that has been widely used in recent years has been required to have a metal-coated structure because the optical fiber is weak in strength. Therefore, it is necessary to insert the optical fiber core wire or the cord into a steel pipe having a diameter of several mm or less and a length of several hundred m or more. Alternatively, a metal wire such as a steel wire may be inserted as a messenger wire into the tube prior to the insertion of the optical fiber core wire.

Conventionally, as a method of inserting a linear body into a tube such as a metal tube,
JP 6244010 A is known. In this method, a pipe passing through the linear body is vibrated, a conveying force is applied to the linear body by the principle of a vibration conveyor, and the linear body is inserted into the pipe.

In this method, when the insertion of the linear body is started, it is necessary to previously insert the linear body into the inlet portion of the tube by a length such that a sufficient conveying force is applied to the linear body. This preliminary insertion is performed manually or by mechanical means such as a pinch roller.

Further, JP-A-61-203411 is known as a method of pushing a linear body into a tube without requiring preliminary insertion. In this method, a linear body such as an optical fiber is pushed in while applying vibration to an overhead ground wire having a hole in the center. By vibrating the overhead ground wire, the state of the linear body in the central hole constantly changes. As a result, the abutting of the tip of the linear body is eliminated,
Further, friction with the hole wall and bending of the linear body are reduced, and the linear body is smoothly pushed.

[Problems to be Solved by the Invention] However, in the linear body insertion method disclosed in JP-A-62-44010, since the pipe inlet end vibrates, the linear body has a large portion in front of the pipe inlet. It swings like a wave, and the centrifugal effect of this causes discharge to the outside of the tube, which prevents entry into the tube. For this reason, pre-insertion is required at the start of insertion, which reduces work efficiency. If the pre-insertion length is short, the linear body is not provided with a sufficient conveying force, and the linear body does not enter the tube. Therefore, the pre-insertion must be performed over a considerable length. In addition, the insertion speed is slow, and it takes a long time to insert the entire length of the tube.

On the other hand, in the method disclosed in the above-mentioned JP-A-61-203411, since the linear body is pushed and inserted into the tube, when the linear body is inserted to some extent, the tip of the linear body or a part in the middle thereof is inserted. Collides with the inner wall of the pipe, and the linear body is easily bent by pushing. As a result, it becomes difficult to push the linear body. Therefore, even if the pipe is vibrated to reduce friction, the linear body cannot be inserted into the long pipe.

Therefore, the present invention is intended to provide a method for inserting a linear body into a long tube, which allows the linear body to be inserted efficiently into the long tube at a high insertion speed.

[Means for Solving the Problems] In the method for inserting a linear body into a tube according to the present invention, the tube is first wound into a coil to form a coil of the tube. Then, an inlet portion of the tube is formed so as to extend from one end of the coil of the tube to the outside of the coil, and the inlet end of the tube is supported so as to be stationary with respect to a plane perpendicular to the longitudinal direction of the tube. Then, while vibrating the coil of the pipe so that any point of the pipe reciprocates along a spiral path, a linear body is pushed into the pipe from the inlet end by a feeder arranged near the inlet end of the pipe. The linear body is inserted into the pipe at the feeding speed of the feeder.

To form a coil of tubing, the tubing is wrapped around a cylinder such as a bobbin or spool. The diameter of the tube coil is 150 mm from the point of penetration and not to apply excessive bending stress to the linear body.
The above is desirable.

To vibrate the coil of the tube, the cylindrical body may be driven by a known means such as a vibration motor or an electromagnetic vibrator. The vibration conditions are, for example, a vibration angle (that is, a spiral lead angle) of 5 to 30 degrees, a vibration frequency of 10 to 30 Hz, and a total amplitude of about 0.2 to 2.0 mm as a vertical component.

To support the inlet end of the tube stationary with respect to a plane perpendicular to the longitudinal direction of the tube, for example, the inlet end of the tube is passed through a cylindrical guide in which the tube fits. The cylindrical guide is made of metal, plastics, etc., and is fixed and supported on the floor or the like. A suitable length of the inlet portion is about 100 to 1000 times the outer diameter of the pipe.

As a feeder for pushing the linear body into the tube from the inlet end, a belt type feeder in which an optical fiber is sandwiched by a pair of endless belts, a roll feeder equipped with a pinch roll, and the like are used. The feeder is located near the inlet end to the extent that the linear body does not flex with the inlet end of the tube.

[Operation] When the pipe coil is vibrated so that any point of the pipe reciprocates along a spiral path, the linear body inside the coiled pipe faces diagonally upward and forward from the inner wall surface of the pipe. Receive power. Due to this force, the linear body jumps obliquely upward and forward in the pipe or slides on the pipe inner wall surface. Further, the linear body is given a pushing force into the tube by the feeder. As described above, the linear body in the pipe is intermittently given a forward force in the coil circumferential direction from the inner wall of the pipe, and is continuously fed with the feeder pushing force to advance in the pipe at the feeder feeding speed. As a result, the advancing speed of the linear body becomes faster.
Due to the bounce of the linear body, the substantial contact area between the linear body and the inner wall surface of the pipe becomes small, and the frictional force that the linear body receives from the inner wall surface of the pipe becomes small. As a result, the pushing force of the feeder effectively acts and the advancing speed of the linear body is increased.

In addition, in the initial stage of insertion, the linear body is pushed into the inlet portion of the pipe by the feeder. Therefore, the preliminary insertion which has been performed conventionally is unnecessary.

[Example] A case in which an optical fiber is inserted into a thin and long steel pipe will be described as an example.

First, an example of an apparatus for performing the insertion method of the present invention will be described. FIG. 1 is an overall view of an apparatus embodying the present invention,
And FIG. 2 is a plan view of a vibration table which is a part of the above apparatus.

The pedestal 11 is firmly fixed to the floor surface 9 so as not to vibrate. At the four corners on the upper surface of the gantry 11, coil springs 18 for supporting the vibration table are attached.

A square board-shaped vibration table 14 is placed on the frame 11 via a support spring 18. A support frame 15 extends downward from the lower surface of the vibration table 14.

A pair of vibration motors 21 and 22 are attached to a support frame 15 of the vibration table 14. The vibration motor 22 is in a position and posture obtained by rotating the vibration motor 21 by 180 degrees around the central axis C of the vibration table 14. Also, the vibration motors 21,2
Reference numeral 2 denotes a posture in which these rotation axes are parallel to the vertical plane including the central axis C, and are inclined at 75 degrees in directions opposite to each other with respect to the vibration table surface. Vibration motor
The unbalanced weights 24 are fixed to both ends of the rotary shafts 21 and 22, and the centrifugal force generated by the rotation of the unbalanced weight 24 applies an exciting force to the vibration table 14 in an oblique direction with respect to these surfaces. The pair of vibration motors 21 and 22 are driven so that the vibration frequency and the amplitude match each other, and the vibration directions deviate from each other by 180 degrees. Therefore, when the vibrations generated by the pair of vibration motors 21 and 22 are combined, the vibration table 14 vibrates so that the central axis of the vibration motors 21 and 22 coincides with the spiral that coincides with the central axis C of the vibration table 14. Since the vibration table 14 is attached to the pedestal 11 via the support spring 18 as described above, the vibration table 14
Vibration is not transmitted to the gantry 11.

Instead of the vibration motors 21 and 22 described above, a vibration device using, for example, a crank, a cam, or an electromagnet may be used as the vibration device, and the vibration motors 21 and 22 may be attached to the vibration table 14 as illustrated. Not limited to.

The bobbin 27 is fixed on the vibrating table 14 such that the bobbin axis is aligned with the central axis C of the vibrating table 14. The tube 1 through which the optical fiber 7 is inserted is wound around the bobbin 27 in a coil shape, and the optical fiber 7 is supplied into the tube from the upper end of the coil 5 of the tube. The diameter of the coil 5 of the tube is preferably 150 mm or more so as not to give an excessive bending stress to the optical fiber. In this embodiment, the optical fiber 7 is an optical fiber element wire pre-coated with resin, and the tube 1 is a steel tube. To ensure that the bobbin 27 receives the vibrations of the vibration motors 21 and 22, the body of the bobbin 27 is supported by a vibration table.
It is fixed to 14 through bolt 31. The bobbin 27 is provided with a groove (not shown) so that the concavities and convexities are continuous in the bobbin axial center direction in the circumferential direction, and the tube 1 is brought into close contact with the groove.

A supply spool 34 of an optical fiber supply device 33 is arranged on the side of the bobbin 27. The supply spool 34 is rotatably supported by the bearing base 35. The supply spool 34 feeds the optical fiber 7 wound around the supply spool 34, and feeds it to the feeder described later.
Supply to 61.

A drive motor 38 is disposed adjacent to the supply spool 34, and the supply spool 34 and the drive motor 38 are operatively connected via a belt transmission 40. The supply spool 34 is rotatably driven by a drive motor 38 to feed the optical fiber 7 and supply the optical fiber 7 to the feeder 61.

Following the supply spool 34, an optical fiber feeding state detection device
47 are arranged. Optical fiber feeding status detector 47
Is composed of a support column 48 and an optical fiber height position detector 49 attached thereto. The optical fiber height position detector 49 includes an image sensor and a light source arranged so as to face the image sensor, and detects the degree of slack of the optical fiber 7 at the passage position of the optical fiber 7. A CCD line sensor is used as the image sensor.

The optical fiber feeding state detection device 47 has a rotation speed control device.
52 is connected, and the rotation speed control device 52 is the detection device 47.
The voltage of the power source 39 of the drive motor 38 is controlled based on the signal from the. That is, the rotation speed of the drive motor 38, that is, the feeding speed of the optical fiber 7 is controlled according to the height position where the optical fiber height position detector 49 is cut off from the optical fiber 7 from the light source.

A holding guide 55 is provided on the output side of the optical fiber feeding state detection device 47.
Is arranged. It is preferable that the entrance and exit of the holding guide 55 be processed into a curved surface without corners, and those materials having a small friction coefficient such as glass or plastic can be used so as not to hinder the transport of the optical fiber 7. .

A feeder 61 is arranged on the output side of the holding guide 55. The feeder 61 is a pair of upper and lower endless belts on the base 62.
63 are provided. The belt 63 is driven by a motor pulley 65, sandwiches the optical fiber 7 from the holding force guide 55, and sends the optical fiber 7 to the tube inlet end 3.

A cylindrical holding metal fitting 69 is arranged on the output side of the feeder 61. The inner diameter of the holding metal fitting 69 is slightly larger than the outer diameter of the pipe 1, and the inlet end portion 3 of the pipe 1 is inserted therein. The inlet end 3 of the pipe 1 is slidable in the longitudinal direction of the pipe, but the movement of the plane perpendicular to the longitudinal direction of the pipe, that is, the movement in the vertical and horizontal directions is restricted.

A solid lubricant made of powder of carbon, talc, or molybdenum disulfide may be supplied to the surface of the optical fiber 7 in front of the holding metal fitting 69.

Next, a method of inserting the optical fiber 7 into the tube 1 by the device configured as described above will be described.

The tube 1 is wound around the bobbin 27 in a coil shape in advance to form the coil 5. The tube 1 is not limited to one-layer winding around the bobbin 27, but in many cases a plurality of layers are wound. In this case, the first layer comes into close contact with the groove of the bobbin 27, but the second and subsequent layers enter between the tubes 1 of the front layer. Then, the bobbin 27 around which the tube 1 is wound is fixed on the vibration table 14 so that the coil axis and the central axis C of the vibration table 14 coincide with each other.

The inlet portion 2 of the tube 1 thus formed in the coil 5 is rewound by one coil, and straightened in the horizontal direction.
Then, the inlet end 3 is passed through the holding metal fitting 69 and spread out in a funnel shape. Then, the base portion 4 of the pipe inlet portion 2 is fixed to the flange 29 of the bobbin 27 with the fastening metal fitting 71.

On the other hand, the optical fiber 7 pre-coated with the fiber strand is wound around the supply spool 34. And supply spool
The optical fiber 7 is pulled out from the optical fiber 34, and the tip portion 8 of the optical fiber 7 is slightly inserted into the tube inlet end portion 3 via the optical fiber feeding state detection device 47, the holding guide 55 and the feeder 61.

Next, the vibration motors 21, 22 and the drive motor 3 for the spool 34
8 and the motor pulley 65 are driven.

Since the vibration motors 21 and 22 are attached to the vibration table 14 in the positions and postures described above, the vibration table
14 receives a torque around the central axis C and a force in the central axis direction. As a result, any point on the vibration table is
It vibrates along the helix H shown in the figure. This vibration V
From the vibration table 14 through the bobbin 27 in sequence to the pipe 1
Is transmitted to the coil 5.

The entrance of the optical fiber 7 into the tube 1 will be described with reference to FIGS. Since the pipe inlet end portion 3 is held by the holding metal fitting 69, the inlet portion 2 vibrates in the pipe longitudinal direction, that is, the pipe 1 does not vibrate vertically and horizontally. Therefore, the forward force f due to vibration does not act on the optical fiber 7 at the inlet portion 2 of the tube 1, and the forward force is applied to the optical fiber 7 by the pushing force F of the feeder 61.

From the base portion 4 of the inlet portion 2 of the pipe 1, that is, in the portion of the coil 5 of the pipe 1, since the pipe 1 vibrates along the spiral,
The optical fiber 7 in this portion receives a force directed obliquely upward and forward from the inner wall surface of the tube. Due to this force, the optical fiber 7 jumps obliquely upward and forward in the tube or slides on the inner wall surface of the tube. In this way, the optical fiber 7 is propelled by the coil circumferential component of the force received from the inner wall of the tube 1 and is pushed by the feeder 61 to enter the tube. Since the coil axis and the central axis C of the vibration table 14 coincide with each other, the optical fiber 7 in the tube makes a circular motion (clockwise P in the example of FIG. 2) about the central axis C. That is, the optical fiber 7 advances in the tube by the two actions of the advancing force by the vibration and the pushing force by the feeder.

By the way, when the optical fiber 7 is pushed into the pipe from the pipe inlet end portion 3 by the feeder 61, as a force against the pushing force acting on the optical fiber 7, the friction resistance with the pipe wall is caused by the bending of the coil wound in a coil shape. Transport resistance There is transport resistance due to the bending of the optical fiber itself. The transport resistance of and is one factor that increases the frictional resistance in the end.

In this invention, since the tube 1 is wound in a coil,
Since the conveyance resistance due to the bending of the tube is larger than that of the straight tube, the pushing force from the tube inlet end is hard to be transmitted over the entire length of the optical fiber. However, since the coil 5 of the tube vibrates spirally, the same (uniform) vibration state is generated in all parts of the tube 1. This vibration is a simple vibration that has a horizontal component in the tangential direction of the coil 5 of the tube and is inclined in the tube longitudinal direction,
A forward force f is generated on the optical fiber 7. This forward force f
Acts tangentially to the coil 5 in all parts of the coil 5 of the tube. Therefore, the optical fiber 7 in the tube is
The forward force f is always applied in the longitudinal direction of the sheet, i.e., in the conveying direction. Since this advancing force f is a force along the bending of the tube, it is avoided that the optical fiber 7 is pressed against the side wall of the tube together with the reduction of friction due to vibration, and a so-called trajectory correcting action is exerted on the optical fiber 7. The optical fiber 7 which receives the pushing force F at the tube inlet end portion 3 and is pushed into the tube shows a state in which the optical fiber 7 enters the inside of the bent tube by the forward force f as if it were straight inside the tube. Of course, the vibration of the tube 1 reduces the frictional resistance between the optical fiber and the tube wall. That is, in the present invention, of the force against the pushing force, the frictional resistance with the pipe wall is eliminated by vibration, and the conveyance resistance due to the bending of the pipe 1 is eliminated by vibration and the forward force f. Furthermore, the forward force f
Does not cause the optical fiber 7 in the tube to sag, so that the pushing force F is more easily transmitted over the entire length of the optical fiber. Further, in order to eliminate the conveyance resistance due to the bending of the optical fiber itself, the optical fiber 7 is twisted and loaded into the pail pack as described later.
Should be pulled out and supplied. The optical fiber 7 in this loaded state has no bend. It is also possible to apply a lubricant to the surface of the optical fiber to reduce the frictional resistance with the tube wall. Further, the conveyance resistance due to the bending of the tube can be reduced by increasing the coil light.

 Returning to FIG. 1, the description will be continued.

When the spiral vibration is applied to the coil 5 of the tube through the vibration table 14, the optical fiber 7 supplied from the tube inlet end 3 above the coil 5 by the feeder 61 continuously enters the tube 1. . That is, the optical fiber 7 is a supply spool.
The optical fiber feeding state detecting device 47,
The holding guide 55, the feeder 61, the pipe inlet end portion 3, the inlet portion 2, the coiled pipe 1, and the pipe outlet end are moved in this order by pushing by the feeder and vibration of the coil 5, and after a predetermined time, are inserted into the entire coil 5. .

During the insertion of the optical fiber 7, if a speed difference occurs between the feeding speed of the optical fiber 7 from the supply spool 34 and the feeding speed of the feeder 61 to the pipe inlet end portion 3, a tensile stress is applied to the optical fiber 7. Or sagging occurs. The optical fiber 7 may unnecessarily sag, or the wire may be broken due to excessive tension, which may hinder the smooth supply of the optical fiber 7. Such a speed difference affects the feeding state of the optical fiber 7 at the position of the optical fiber height position detector 49, which is immediately detected by the detector 49. That is, if the optical fiber height position detector 49 detects that the optical fiber 7 is too tight, a signal is sent to the drive motor 38 to increase the spool rotation speed and increase the supply speed of the optical fiber 7. If too much slack in the optical fiber 7 is detected, the drive motor 38 is similarly controlled to reduce the supply speed of the optical fiber 7. In this way, the abnormal transport state of the optical fiber 7 is immediately detected, corrected, and returned to the normal transport state (a slightly slack state as shown in FIG. 1).

Since a resonance phenomenon occurs during insertion of the optical fiber 7 into the tube 1 and the frictional resistance acting on the optical fiber gradually increases depending on the condition of the inner surface of the tube and the surface of the optical fiber, the insertion speed of the optical fiber 7 is not always constant. Rather, it may fluctuate. Fluctuation (deceleration) in the speed of the optical fiber 7 in the pipe
When this occurs, slack of the optical fiber 7 occurs between the tube inlet end portion 3 and the feeder 61, which may hinder smooth supply of the optical fiber 7. In such a case, the optical fiber height position detector 49 is provided between the feeder 61 and the holding metal fitting 69 as described above, and the optical fiber height position detector 49 is provided.
The feed speed of the feeder 61 may be adjusted (decelerated) based on the signal from the.

FIG. 4 shows another embodiment of the present invention. In addition,
The same parts as those of the apparatus and members shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the means for supplying the optical fiber 7 to the feeder 61 is different from that of the first embodiment. That is, the pail pack 73 that accommodates the optical fiber 7 is arranged laterally of the feeder 61. And Pail Pack 73
A curved tubular guide 75 extends from directly above to the feeder entrance.

When taking out the optical fibers 7 stacked and stored in a loop form in the pail pack from the pail pack 73, the optical fibers 7 are drawn out in order from the upper part of the loop-shaped laminate to the upper part of the pail pack. At this time, the optical fiber has a maximum of 36 per loop.
Receives 0 ° twist. This twist is warped by trying to return to the original state while being inserted in the pipe, which causes resistance to conveyance and hinders insertion. Therefore, it is preferable to apply a reverse twist to the optical fiber 7 in advance so as to cancel the twist received when the optical fiber 7 is taken out from the pail pack 73, and store the optical fiber 7 in the pail pack 73. The optical fiber housed in this way has no bending like the optical fiber wound on the spool, and the inertial resistance of the succeeding optical fiber does not act on the optical fiber to be taken out, as shown in FIG. It is not necessary to provide such an optical fiber feeding state detecting device in front of the feeder 61.

(Specific Example) In order to confirm the effect of the present invention, an optical fiber was inserted into a steel pipe under the following conditions by the device shown in FIG.

(1) Test material Steel tube coil: 0.8-2.0mmφ (0.5-1.6m) in outer diameter (inner diameter)
m), and 7 types of steel pipes with a length of 1 Km, which are aligned and wound on a steel bobbin with a winding diameter of 1200 mm (1 layer winding).

Optical fiber: The following was used.

An optical fiber with a diameter of 0.4 mm, which is a silica glass optical fiber (diameter 125 μm) coated with silicone resin.

(2) Vibration condition: Since the steel pipe coil used in this embodiment has one winding layer, the vibration conditions are almost the same in all parts of the pipe. Vibration angle of the coil with respect to the horizontal plane 15 degrees Frequency 20Hz Vertical component of total amplitude 1.25 to 1.55mm As a result of inserting the optical fiber through the steel pipe under the above conditions, the optical fiber does not require preliminary insertion and is extremely smooth inside the steel pipe. Was inserted in. The average insertion speed (feeding speed of the feeder) was 3 to 5 m / min, and it was confirmed that the steel tube was inserted into the entire length of the steel pipe within 3 to 6 hours. It was found that the optical fiber can be inserted into a small diameter tube of 2 mm or less or a long tube of about 1 Km, and the inserted optical fiber does not deteriorate.

If the optical fiber is inserted only by vibration, 6
It was inserted into the entire length of the steel pipe within 10 hours. In addition, JP-A-61-
According to the method of pushing the optical fiber while vibrating the tube disclosed in 203411, the optical fiber can be pushed into the tube only up to 30 m.

In the above embodiment, the linear body is an optical fiber, but the present invention is also applied to insertion of a linear body other than the optical fiber, for example, a metal wire such as a copper wire or a steel wire or a non-metal wire such as plastics. It Supply of the linear body into the pipe is 1
Not only the number of books but also a plurality of tubes is possible in relation to the inner diameter of the pipe and the diameter of the linear body. As the pipe through which the linear body is inserted, various concrete examples such as an aluminum pipe and a synthetic resin pipe may be considered in addition to the above steel pipe. Further, a post-process such as surface reduction processing after inserting the linear body into the metal tube may be added, and may be appropriately performed by a practitioner depending on the situation. Furthermore, although the central axis of the coil of the tube does not necessarily need to coincide with the central axis of the helix, it is preferable that both axes coincide, and the central axis of the coil of the tube is not necessarily vertical but may be vertical. Desirably.

If the pipe is very long and it is difficult to apply the pushing force of the feeder over the entire length of the pipe, the feeder is released from the middle and the insertion is switched only by vibration.

EFFECTS OF THE INVENTION According to the present invention, the pipe has a small diameter (for example, the outer diameter of the pipe is 2 m).
Even if the length is less than or equal to m) and the length is long (for example, the tube length is about 1 km), the optical fiber can be inserted into the tube at a high insertion speed without tedious preliminary insertion.

[Brief description of drawings]

1 is a side view showing an example of an apparatus for inserting an optical fiber by the method of the present invention, FIG. 2 is a plan view of a vibration table of the apparatus, and FIGS. 3 (a) and 3 (b) are pipe inlets, respectively. FIG. 4 is a side view showing another example of a device for inserting an optical fiber, and FIG. 1 ... pipe, 2 ... pipe inlet part, 3 ... pipe inlet end,
5 ... Tube coil, 7 ... Optical fiber, 11 ... Stand, 14
…… Vibration table, 21,22 …… Vibration motor, 27 …… Bobbin, 33 …… Optical fiber feeder, 38 …… Drive motor, 47
...... Optical fiber feeding status detection device, 52 ...... Control device, 55
……, 61 …… Electromagnetic feeder, 69 …… Holding bracket, 73 ……
Pail pack.

Claims (1)

(57) [Claims] 1. A pipe is wound into a coil to form a coil of the pipe, and an inlet portion of the pipe is formed so as to extend from one end of the coil of the pipe toward the outside of the coil. Oriented near the inlet end of the tube while vibrating the coil of the tube so that any point of the coiled tube reciprocates along a spiral path. A method for inserting a linear body into a pipe, wherein the linear body is inserted into the pipe from the inlet end by a feeder to insert the linear body into the pipe at a feeding speed of the feeder.