JPH0769500B2 - 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 tube, and more particularly to a method for inserting a linear body into a tube by utilizing vibration.

INDUSTRIAL APPLICABILITY The present invention is used for manufacturing an optical fiber cable, an electric wire, a composite structure tube or the like in which an optical fiber, a metal wire or other linear body is inserted into a protective tube or a sheath.

[Prior Art] It may be necessary to insert a linear body into a long tube or the like. For example, optical communication cables that have been widely used in recent years have been required to have a structure with a metal coating because the optical fiber is weak in strength. For this reason, it is necessary to insert the optical fiber core wire or 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 for producing a linear wire in which a linear body is inserted in a tube such as a metal tube, Japanese Patent Laid-Open No. 58-186110 and Japanese Patent Laid-Open No. 62-44
010 is known. According to these methods, a carrier member or a tube through which the linear body is inserted is vibrated, a conveying force is applied to the linear body by the principle of a vibrating conveyor, and the linear body is inserted into the carrier member or the pipe.

In these methods, when the insertion of the linear body is started, the linear body is previously inserted into the inlet portion of the tube by a length such that a sufficient conveying force is applied to the linear body. This pre-insertion can be done manually or by mechanical means such as a pinch roller. Since the inlet end of the pipe is fixed to the coil of the pipe, it vibrates together with the coil.

[Problems to be Solved by the Invention] However, the conventional linear body insertion method has the following problems.

(A) Since the pipe inlet end is vibrating, the linear body sways so that the portion in front of the pipe inlet end is largely undulated, and the centrifugal effect of this causes a discharge force to the outside of the pipe, causing it to enter the pipe. Disturbed. 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.

(B) The linear body is repeatedly bent before the end of the pipe inlet, and microcracks occur especially in the optical fiber. Further, the linear body comes into contact with the tube end due to the oscillating motion and causes scratches.

Therefore, the present invention is intended to provide a method for inserting a linear body into a tube that is efficient and allows the linear body to be inserted without causing damage.

[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, the inlet portion of the tube is curved away from the coil of the tube so that the inlet portion rises, and the inlet end is fixedly supported in a stationary state. Then, while feeding the linear body and supplying it to the inlet end, the coil of the tube is vibrated so that an arbitrary point of the tube reciprocates along a spiral path.

To form a coil of tubing, the tubing is wrapped around a cylinder such as a bobbin or spool. The diameter of the coil of the tube is preferably 150 mm or more from the viewpoint of insertability and not giving excessive bending stress to the linear body.

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.

The inlet portion in a standing posture vibrates together with the coiled portion of the pipe, but since the upper end of the inlet portion, that is, the inlet end is stationary and fixed, a bending moment is added to this portion. Therefore, the length of this portion and the radius of curvature of the curvature must be large to some extent so that excessive stress is not applied to the inlet portion. Appropriate values for these lengths and radii of curvature vary depending on the material of the pipe. For example, in the case of steel pipes, it is practical that the length and radius of curvature are 100 to 300 times and 50 to 200 times the pipe outer diameter, respectively. .
In addition, the inlet portion does not need to rise vertically, and may be inclined so that the linear body slides down inside the pipe of the inlet portion. The inlet portion of the tube may simply be curved two-dimensionally, i.e. in a vertical plane, or it may be helically curved three-dimensionally.

In order to send out the linear body to the inlet end of the tube, for example, a reel on which the linear body is wound is rotationally driven by a motor, or an advancing force is applied to the linear body by an electromagnetic feeder. The magnitude of the force to be sent out is sufficient as long as it can supply the linear body to the inlet end of the pipe, and it is not necessary to push the linear body into the pipe for insertion.

[Operation] When the coil of the pipe is vibrated so that any point of the pipe reciprocates along a spiral path, the linear state inside the coiled pipe is a force directed diagonally upward and forward from the inner wall surface of the pipe. Receive.
Due to this force, the linear body jumps obliquely upward and forward in the pipe or slides on the pipe inner wall surface. In this way
The linear body in the pipe is advanced in the pipe by being intermittently supplied with a conveying force in the circumferential direction of the coil from the inner wall of the pipe.

Further, at the start of insertion, the linear body outside the tube sent out to the inlet end is drawn into the tube by gravity and advances in the inlet part of the tube, and subsequently advances due to vibration of the coil of the tube. 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 carrying out the insertion method of the present invention will be described. FIG. 1 is an overall view of an apparatus for carrying out the present invention, and FIG. 2 is a plan view of a vibration table which is a part of the apparatus.

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

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 the support frame 15 of the vibration table 14. The vibration motor 22 is in a position and posture in which the vibration motor 21 is rotated 180 degrees around the central axis C of the vibration table 14. In addition, the vibration motors 21,22
Have their rotation axes parallel to the vertical planes including the central axis C and inclined by 75 degrees in opposite directions with respect to the vibration table surface. Vibration motor 2
1,22 has unbalanced weights 24 fixed to both ends of the rotating shaft,
Vibration table 14 due to centrifugal force generated by rotation of unbalanced weight 24
An oblique excitation force is applied to this plane. 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 gantry 11 via the support spring 18 as described above, the vibration of the vibration table 14 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 this 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 a fiber pre-coated with resin, and the tube 1 is a steel tube. In the bobbin 27, the outer peripheral edges of the lower flanges 29 of the bobbin 27 are fixed to the vibration table 14 by fixing jigs 31 so as to surely receive the vibrations of the vibration motors 21 and 22. The bobbin 27 is provided with a groove (not shown) in the circumferential direction so that the projections and depressions are continuous in the axial direction of the bobbin.
Are getting closer.

A supply spool 34 of the optical fiber supply device 33 is arranged diagonally above the bobbin 27. The supply spool 34 is rotatably supported by the bearing base 35. The supply spool 34 delivers the optical fiber 7 wound around the supply spool 34, and the inlet end 3 of the tube 1
Supply to.

A drive motor 38 is arranged adjacent to the supply spool 34, and the supply spool 34 and the drive motor 38 are a belt transmission device.
Operatively coupled through 40. The supply spool 34 is rotationally driven by a drive motor 38 to feed the optical fiber 7 and supply the optical fiber 7 to the tube 1 wound around the bobbin 27.

A holding guide 43 is provided in the vicinity of the optical fiber feeding position of the supply spool 34. The holding guide 43 holds the optical fiber 7 delivered from the supply spool 34.

An optical fiber feeding state detecting device 47 is arranged following the holding guide 43. The optical fiber feeding state detecting device 47 comprises a support column 48 and an optical fiber height position detector 49 attached to the supporting column 48. 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 includes a rotation speed control device 52.
The rotation speed control device 52 controls the voltage of the power supply 39 of the drive motor 38 based on the signal from the detection device 47. 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 7 blocks the optical fiber height position detector 49 from the light source.

During the insertion of the optical fiber 7 into the tube 1, the insertion speed of the optical fiber 7 is not always constant but may fluctuate depending on the resonance phenomenon and the state of the inner surface of the tube and the state of the surface of the optical fiber. Therefore, if the speed of the optical fiber 7 in the tube 1 fluctuates, it affects the feeding state of the optical fiber 7 outside, and if the feeding speed cannot follow the insertion speed of the optical fiber 7, the optical fiber 7 is required. The above-mentioned slack or disconnection due to excessive tension may occur, which may hinder smooth supply of the optical fiber 7. However, as described above, the supply spool 34 is driven and rotated, and the rotation speed of the supply spool 34 is changed or stopped depending on the transfer state of the optical fiber 7 in the tube 1.
Can always be supplied within the required supply rate range.
In other words, the optical fiber 7 does not become too tight or too slack, and can be maintained in the best condition (slightly slack condition as shown in FIG. 1). As a result, the optical fiber 7
The optical fiber 7 can be inserted into the tube 1 without any trouble without giving a burden to itself, that is, without giving a resistance to the insertion of the optical fiber 7. By the way, the diameter is 0.4mm
When inserting the optical fiber of No. 2 into a steel tube having an inner diameter of 0.5 mm, if the force applied to the optical fiber toward the optical fiber supply side is 20 gf or more, the optical fiber will not enter the tube.

A bend 55 is installed on the output side of the optical fiber feeding state detection device 47. The bend 55 is an optical fiber feeding state detecting device.
Guide the optical fiber 7 from 47 to the tube inlet end 3.

As shown in FIG. 3, a holding fitting 57 is provided at the lower end of the bend 55. The inside of the holding metal fitting 57 has a funnel shape.

The holding guide 43 and the inlet / outlet of the bend 55 are preferably processed into curved surfaces without corners, and those materials having a small friction coefficient such as glass or plastic are used so as not to hinder the transfer of the optical fiber 7. be able to. In either of the holding guide 43 and the bend 55, carbon is attached to the surface of the optical fiber 7 passing therethrough,
A solid lubricant made of powder such as talc or molybdenum disulfide may be supplied.

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

In advance, the tube 1 is wound around the bobbin 27 in a coil shape to form the coil 5.
To form. The tube 1 is not limited to the one-layer winding for the bobbin 27,
Often wound in multiple layers. In this case, the first layer is the bobbin
Although it closely adheres to the groove of 27, it will enter between the tubes 1 of the previous layer after the second layer. Then, the coil axis and the vibration table 14
The bobbin 27 around which the tube 1 is wound is fixed on the vibrating table 14 so that the central axis lines C of the same are aligned.

The tip portion of the tube 1 thus formed on the coil 5 is rewound by one coil, and cut to an appropriate length, and then separated from the coil 5 and bent upward. Then, the inlet end 3 is passed through the guide hole 58 of the holding metal fitting 57 and expanded in a funnel shape. Then, it is fixed to the holding fitting 57 by the tightening fitting 59. Further, the base portion 4 of the pipe inlet portion 2 is a flange of the bobbin 27.
It is fixed to 29 with the clamp 61 by stationary.

On the other hand, the optical fiber 7 pre-coated with the fiber strand is wound around the supply spool 34. And supply spool 34
The optical fiber 7 is pulled out from the holder, and the tip 8 of the optical fiber 7 is positioned at the pipe inlet end 3 from the holder 57 via the holding guide 43, the optical fiber feeding state detecting device 47 and the bend 55.

Next, the vibration motors 21, 22 and the drive motor 38 for the spool 34 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 about the central axis C and a force in the central axis direction. As a result, an arbitrary point on the vibration table vibrates along the spiral H shown in FIG. This vibration V is
The vibration is transmitted from the vibration table 14 to the coil 5 and the inlet portion 2 of the pipe 1 through the fixing fitting 31 and the bobbin 27 in this order.

The entrance of the optical fiber 7 into the tube 1 at the start of insertion will be described with reference to FIGS. 3 and 4 (the tube entrance portion 2 is shown as a straight tube for convenience). Transition point T that coincides with the direction of the center of curvature of 2
There is. In the section between the inlet end 3 and this transition point T (hatched portion in FIG. 3), the optical fiber 7 is vibrated by the inner wall surface of the tube, but this vibration does not generate a carrying force. However, in this section, the tip portion of the optical fiber 7 advances (falls) due to gravity. Also, in this section, the vibration prevents the optical fiber 7 from sliding on the inner wall surface of the tube, reduces the frictional resistance between the optical fiber 7 and the inner wall surface of the tube, and assists the forward movement of the tip portion of the optical fiber 7 by gravity. .

In the section between the transition point T and the reference 4 of the entrance portion 2, the transition point T
Causes a component in the conveyance direction of the vibration, which gradually increases. The optical fiber 7 behind this section, that is, between the inlet end 3 and this transition point T is inside the tube, and since the forward force due to gravity is acting on it, the optical fiber 7 at the tip portion of this section is in this section. Does not act on the forward blocking forces (centrifugal effect and static inertia of the rear optical fiber). Therefore, the tip portion of the optical fiber 7 advances as long as the conveying force due to the vibration is small (the angle formed by the vibration direction and the insertion direction is an acute angle). That is,
When the tip of the optical fiber 7 passes through the transition point T, the optical fiber 7 advances due to the vibration carrying force. When the tip of the optical fiber 7 reaches the base portion 4 of the tube inlet portion 2, the base portion 4 is located at the uppermost end of the coil 5 of the tube, and the optical fiber 7 extends substantially along the tangential direction of the coil 5 of the tube. It is inserted into the tube 1.

By the way, in the technique disclosed in Japanese Patent Laid-Open No. 58-186110, the tip of the optical fiber is inserted by a predetermined distance L before the insertion is started, as shown in FIG. in this way,
A carrier force by vibration is applied to the optical fiber 7 from the position of the inlet end 3 of the tube 1 to overcome the force due to the centrifugal effect and the force due to the static inertia of the optical fiber 7 behind the inlet end at this distance L. Must get That is, there is a point P at which the conveying force due to the vibration and the force for preventing the advance of the optical fiber become equal, and the distance L is a distance exceeding the distance between the point P and the inlet end 3. Even if the tip of the optical fiber is inserted during this time, the optical fiber does not move forward, and the point P
The optical fiber starts to advance only after being inserted beyond.

The optical fiber 7 in the coil 5 portion of the tube 1 is propelled by the coil circumferential component of the force received from the inner wall of the tube 1 and enters 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.

Returning to FIG. 1 again, description will be made.

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 continuously enters the tube 1 by the vibrating article conveying force. go. That is, the optical fiber 7 is connected to the supply spool 34.
From the holding guide 43, the optical fiber feeding state detecting device 47, the bend 55, the pipe inlet end 3, the inlet portion 2, the coiled pipe 1, and the pipe outlet end in this order by the vibration of the coil 5, After a lapse of time, the entire coil 5 is inserted.

If the intra-tube insertion speed fluctuates due to some factor during the insertion of the optical fiber 7, this will affect the feeding state of the optical fiber 7 at the position of the optical fiber height position detector 49, which will be detected. Immediately detected by the device 49. That is, if the optical fiber height position detector 49 detects that the optical fiber 7 is overtensioned, the signal is output to the drive motor.
38 and the spool rotation speed is increased to increase the optical fiber 7
Increase the feeding speed of. When the excessive slack of the optical fiber 7 is detected, the drive motor 38 is similarly controlled to slow down the supply speed of the optical fiber 7. In this way, the abnormal transport state of the optical fiber 7 is immediately detected and corrected,
Return to the normal transfer state.

(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 pipe coil: Outer diameter (inner diameter) 0.8 to 2.0 mmφ (0.5 to 1.6 m)
m), 7 types of steel pipes with a length of 10 km, and 7 types of steel pipe coils that are wound in turns (10 to 20 layers) on a steel bobbin with a winding diameter of 1200 mm.

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: The steel pipe coil used in this example has a wound layer.
Since there are 10 to 20 layers, almost every part of the pipe has the same vibration condition.

Vibration angle of the coil with respect to the horizontal plane 15 degrees Frequency 20Hz Vertical component of full amplitude 1.25 to 1.55mm As a result of inserting the optical fiber into the steel pipe under the above conditions, the optical fiber is extremely smooth in the steel pipe without any need for preliminary insertion. Was inserted in. The insertion speed is 2 to 4 m / min,
It was confirmed that the entire length of the steel pipe was inserted within a predetermined time.
Even when inserting an optical fiber into a small diameter tube of 2 mm or less, 10K
It was found that it is possible even when it is inserted into a long tube of about m, and of course, the inserted optical fiber does not deteriorate.

Although the linear body is an optical fiber in the above embodiment, 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 can 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, the central axis of the coil of the tube does not necessarily have to coincide with the central axis of the helix, but it is desirable that both axes coincide with each other, and the central axis of the coil of the tube does not necessarily have to be vertical but is vertical. Is desirable.

EFFECTS OF THE INVENTION According to the present invention, the pipe has a small diameter (for example, the pipe outer diameter is 2 mm).
The following), even if the length is long (for example, the pipe length is 1 km or more), it can be inserted without troublesome preliminary insertion and without degrading or damaging the linear body.

[Brief description of drawings]

FIG. 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 FIG. 3 is a longitudinal sectional view showing a fixed state of a pipe inlet portion. FIG. 4, FIG. 5 and FIG. 5 are drawings for explaining the transporting action of the optical fiber at the pipe inlet portion, respectively. FIG. 4 shows the case according to the present invention and FIG. 5 shows the case according to the conventional method. . 1 ... Pipe, 2 ... Pipe inlet part, 3 ... Pipe inlet end, 5
…… Coil of tube, 7 …… Optical fiber, 11 …… Stand, 14 ……
… Vibration table, 21,22 …… Vibration motor, 27 …… Bobbin, 33 …… Optical fiber feeder, 38 …… Drive motor, 43
...... Holding guide, 47 ...... Optical fiber feeding status detector,
52 …… Control device, 55 …… Bend, 59,61 …… Clamping fitting.

Claims (1)

[Claims] 1. A tube is wound into a coil to form a coil of the tube, and a linear body is supplied from one end of the tube so that any point of the tube reciprocates along a spiral path. In a method of inserting a linear body into a pipe by vibrating a coil, the inlet part of the pipe is curved away from the coil of the pipe so that the inlet part rises, and the inlet end is fixed and supported in a stationary state. A method for inserting a linear body into a pipe, which is characterized in that it is sent out and supplied to the inlet end.