JP5550952B2 - Manufacturing method of cable protection tube - Google Patents

Description

  The present invention relates to a cable protection tube that is used when a cable such as a communication cable is buried in the underground, and that protects the cable from underground water and the like, and a method of manufacturing the cable protection tube.

  For example, a communication cable is branched from a main line cable and drawn into a house or a store. Conventionally, in order to improve the landscape of the road, such a communication cable is put into a common ditch constructed under the road surface of the road together with a gas pipe and a water and sewage pipe to make it underground. However, underground subsidence due to joint ditches has a high initial construction cost, and the current situation is that it is only partially spread mainly on urban highways.

  For this reason, a plurality of trunk cables and lead-in cables of communication cables are accommodated in cable protection pipes and buried in the ground in a state where the cables are protected from groundwater or the like. Also, if each trunk cable or lead-in cable is housed and buried in a cable protection tube, each cable occupies a large proportion of the space below the road surface. Therefore, a plurality of trunk cables and lead-in cables are grouped together. Cable protection pipes that can be accommodated are put into practical use, and are effectively used especially for underground use under relatively narrow roads such as residential areas and shopping streets.

  Further, in this type of cable protection tube, a protection tube main body formed with a pair of protrusions protruding inward from the inner peripheral surface and extending in the axial direction, and a pair of recesses on the pair of protrusions of the protection tube body It is inserted and installed inside the protective tube main body and is configured to include a separator that divides the internal space of the protective tube main body into a space that accommodates a plurality of main line cables and a space that accommodates a plurality of lead-in cables. There are some (see, for example, Patent Document 1).

  In this cable protective tube, the convex portion of the protective tube main body and the concave portion of the separator are engaged, so that the separator does not rotate, and the space for accommodating the main line cable and the space for accommodating the lead-in cable are provided. It can be reliably partitioned and held. And, by accommodating a plurality of trunk cables and a plurality of lead-in cables in each space of the cable protection tube configured in this way and burying them in the ground, the proportion of each cable in the space below the road surface is effectively increased. Can be reduced. For this reason, in the future, even if it is necessary to embed trunk cables and lead-in cables under narrower roads in the future, the cable protection tube will be used. Adopting this makes it possible to respond sufficiently.

JP 2008-67455 A

  On the other hand, the above-mentioned cable protection tube configured to divide the inside of the protection tube main body into two spaces by a separator is provided with a cylindrical receiving tube manufactured separately from the protection tube main body on the end side of the protection tube main body. They are used by connecting them using an adhesive or the like, and connecting the cable protection tubes in series via the receiving tube.

  Thus, the protective tube main body and the receiving tube are manufactured separately, and the receiving tube is connected to the protective tube main body, resulting in a decrease in productivity, and further, at the joint between the protective tube main body and the receiving tube. There is a possibility that the cable may be caught, resulting in a decrease in cable insertability and damage to the cable, and there remains room for improvement in this respect.

  In order to achieve the above object, the present invention provides the following means.

The manufacturing method of the cable protection tube according to claim 1 , wherein the cylindrical protection tube main body provided with a convex portion protruding inward from the inner peripheral surface and extending in the axial direction is engaged with the concave portion, and the convex portion is engaged. A plate-like separator inserted and installed inside the protective tube main body, and a method of manufacturing a cable protective tube configured to accommodate a cable in an internal space of the protective tube main body partitioned by the separator, The raw tube manufacturing step of manufacturing the original pipe having the convex portion on the inner peripheral surface by extrusion molding, and the inner peripheral surface on the end portion side of the original pipe is subjected to a thickening process so that the convex portion is embedded. A thickened portion forming step for forming a thickened portion, a cutting step for cutting the convex portion together with the thickened portion to make the end portion side of the original tube have a predetermined thickness, and an end of the original tube Receptor molding that heats and softens the part side and expands the diameter to form a receiver The protection tube main body is manufactured by integrally forming the receiving port for connecting the cable protection tubes to each other on the end side. It is characterized by that.

In the manufacturing method of the cable protection tube according to claim 1, the receiving port (cylindrical (cylindrical) receiving port having no protruding portion) formed in a cylindrical shape without providing the protruding portion is an end portion of the protective tube main body. A protective tube body formed integrally on the side can be manufactured. For this reason, it is possible to manufacture the protective tube main body and the receiving tube separately from the conventional cable protective tube, and to eliminate the need to connect the receiving tube to the protective tube main body, thereby improving productivity. . In addition, by manufacturing a protective tube main body that is formed by integrally molding the receiving port on the end side, the cable is not caught at the joint between the protective tube main body and the receiving tube as in the past, improving the cable insertability. It becomes possible to prevent the cable from being damaged.

  Further, in the thickened portion forming step, the thickened portion is not formed on the inner peripheral surface on the end portion side of the original pipe, and only the convex portion is cut so that the end portion side of the original tube has a predetermined thickness (the convex portion is eliminated). However, in this case, the protective tube main body may be cut together with the convex portion, and the end portion side of the original tube may be partially thinned. On the other hand, a thickened part is formed on the end side of the original pipe in the thickened part forming step, and the convex part is cut together with this thickened part, so that the end side of the original pipe is partially thinned. Can be reliably prevented, and a desired wall thickness can be secured and the end side of the original tube can be cut.

It is a cross-sectional view showing a cable protection tube according to an embodiment of the present invention. It is a X1-X1 arrow directional view of Drawing 1, and is a longitudinal section showing a cable protection pipe (protection pipe part and separator) concerning one embodiment of the present invention. In the manufacturing method of the cable protection pipe concerning one embodiment of the present invention, it is a perspective view showing the original pipe manufactured at the original pipe manufacturing process. In the manufacturing method of the cable protection pipe concerning one embodiment of the present invention, it is a transverse cross section showing the original pipe manufactured at the original pipe manufacturing process. In the manufacturing method of the cable protective tube which concerns on one Embodiment of this invention, it is a cross-sectional view which shows the state which formed the thickening part in the internal peripheral surface of the edge part side of an original pipe. In the manufacturing method of the cable protective tube which concerns on one Embodiment of this invention, it is a cross-sectional view which shows the state which cut the convex part with the thickening part formed in the internal peripheral surface at the edge part side of an original pipe. In the manufacturing method of the cable protective tube which concerns on one Embodiment of this invention, it is a cross-sectional view which shows the state which expanded the end part side of the original pipe, and shape | molded the receiving port.

  Hereinafter, with reference to FIGS. 1 to 7, a cable protection tube and a method for manufacturing the cable protection tube according to an embodiment of the present invention will be described. The present embodiment is used when a cable is buried in a basement, and relates to a cable protection tube for housing a cable and protecting it from groundwater and a method for manufacturing the cable protection tube. In the present embodiment, the description will be made assuming that the cable is a communication cable.

  The cable protection tube A of this embodiment is made of, for example, hard vinyl chloride, and is inserted into the tubular protection tube body 1 and the inside of the protection tube body 1 (internal space 1a) as shown in FIGS. A plate-shaped separator 2 is provided.

  As shown in FIG. 1, the protective tube main body 1 is connected to a protective tube portion 3 formed in a cylindrical shape having a substantially constant outer diameter and inner diameter in the direction of the axis O <b> 1, and one end portion 3 a of the protective tube portion 3. A portion 3 and a receiving port (receiving portion) 4 formed integrally with the portion 3 are provided. Further, as shown in FIG. 1 and FIG. 2, the protective tube main body 1 protrudes inward from the inner peripheral surface 1 b (the inner peripheral surface 3 b of the protective tube portion 3), and from the one end portion 3 a of the protective tube portion 3 to the other end portion. A pair of convex portions 5 and 6 extending in the direction of the axis O1 up to 3c is provided. The pair of convex portions 5 and 6 are each formed in a trapezoidal cross section, and are provided at left and right symmetrical positions with the axis O1 therebetween. In addition, the convex parts 5 and 6 may be formed, for example in the cross-sectional triangle shape, and do not need to be limited to a cross-sectional trapezoid shape.

  As shown in FIG. 1, the receiving port 4 is for connecting the cable protection tubes A to each other, and the central axis is coaxially arranged with the central axis of the protective tube portion 3 (the axis O1 of the protective tube main body 1). And it is integrally molded by the edge part (one end part 1c) side of the protection tube main body 1. FIG. Further, the receiving port 4 is formed in a substantially cylindrical shape whose diameter is expanded with respect to the protective tube main body 1 without providing the convex portions 5 and 6 unlike the protective tube portion 3. Further, the receiving port 4 of the present embodiment gradually increases in inner diameter and outer diameter from the one end 4b connected to the one end 3a of the protective tube portion 3 toward the other end 4c side in the axis O1 direction (the end 1c side of the protective tube main body 1). The enlarged diameter portion 7 having a large diameter and the joined portion 8 having an inner diameter and an outer diameter substantially constant from the enlarged diameter portion 7 to the other end 4c. Further, the joint portion 8 is formed such that the inner diameter thereof is substantially the same as the outer diameter of the protective tube main body 1. Further, an annular seal material fitting groove 9 that is recessed from the inside to the outside and that extends in the circumferential direction and is connected is formed on the inner peripheral surface 4 a of the joint portion 8.

  As shown in FIG. 2, the separator 2 inserted and installed in the inside 1a of the protective tube main body 1 extends in the direction of the axis O1 of the protective tube main body 1 in a state of being attached to the internal 1a of the protective tube main body 1. A plate-like portion 2a that divides the internal space 1a of the tube main body 1 into an upper space 10 and a lower space 11, and a pair of elastically deformable members that extend downward by connecting the upper ends to both ends of the plate-like portion 2a. The locking portions 2b and 2c are formed. The pair of locking portions 2b and 2c are each formed in an arc shape along the inner peripheral surface 3b of the protective tube portion 3 of the protective tube main body 1, and the convex portions 5 and 6 between the upper end and the lower end. It is formed with a recess 12 that engages with.

  And the separator 2 formed in this way engages each recessed part 12 of a pair of latching | locking parts 2b and 2c with the convex parts 5 and 6 of the protective tube part 3 (protective tube main body 1), and plate-like part 2a The internal space 1a of the protective tube portion 3 is installed so as to be divided into an upper space 10 and a lower space 11. At this time, the pair of locking portions 2b and 2c are formed in an arc shape along the inner peripheral surface 3b of the protective tube portion 3 and are formed so as to be elastically deformable. While engaging the recessed part 12, the outer surface of each latching | locking part 2b, 2c is pressed and closely_contact | adhered to the inner peripheral surface 3b of the protective tube part 3. FIG. Thereby, the separator 2 is hold | maintained in the state which divided the internal space 1a of the protection tube main body 1 into the upper space 10 and the lower space 11 with the plate-shaped part 2a.

  In the cable protection tube A of the present embodiment configured as described above, as shown in FIGS. 1 and 2, a plurality of main line cables 13 are accommodated in a lower space 11 partitioned by the separator 2 while being inserted into the sheath tube 14. A plurality of lead-in cables 15 are accommodated in the upper space 10. Further, the end portion (the other end portion 1d) of the protection tube main body 1 of the other cable protection tube A is inserted into the joint portion 8 of the receiving port 4, and the cable protection tubes A are connected to each other. At this time, by connecting the cable protection tubes A with the O-ring (seal material) 16 fitted in the seal material fitting groove 9 of the joint 8 of the receiving port 4, the tightness in the cable protection tube A is achieved. Is secured.

  On the other hand, when manufacturing the cable protection tube A (protection tube body 1) of the present embodiment, as shown in FIGS. 3 and 4, a cylindrical shape having a pair of convex portions 5 and 6 on the inner peripheral surface 20a. The raw tube 20 is manufactured by extrusion molding (original tube manufacturing process).

  Next, as shown in FIG. 5, the thickened portion 21 is formed by performing a thickening process on the inner peripheral surface 20 a on the end 20 b side of the original tube 20 (a thickened portion forming step). In the thickened portion forming step of the present embodiment, the thickened portion 21 is formed so that the convex portions 5 and 6 on the end 20b side of the original tube 20 are completely embedded. In addition, you may form the thickening part 21 so that a part at the protrusion direction front end side of the convex parts 5 and 6 may remain exposed. Moreover, what is necessary is just to form this thickening part 21 using a means suitably. For example, an inner mold having a recess corresponding to the shape of the thickened portion 21 is inserted into the inner hole (inside) on the end 20 b side of the original pipe 20, and an outer mold is installed outside the original pipe 20. The mold is clamped, and molten resin is injected into the cavity between the inner surface of the inner mold and the inner peripheral surface 20a on the end 20b side of the original tube 20, or on the inner peripheral surface 20a on the end 20b side of the original tube 20 It is possible to form the thickened portion 21 by attaching the thickening material and heating the end portion 20b side of the raw tube 20 and the thickening material so as to be fused together.

  Next, as shown in FIG. 6, the convex parts 5 and 6 are cut with the thickened part 21 (cutting process). At this time, the inner peripheral surface 21a on the end 20b side of the original tube 20 is circular in cross-sectional view (the end 20b side of the original tube 20 is formed in a cylindrical shape without the convex portions 5 and 6), and the original tube 20 The wall thickness on the end 20b side is set to a predetermined wall thickness. Moreover, what is necessary is just to perform using this means also in this cutting process. For example, a grinding rod is inserted into the inner hole (inside) from the end 20 b side of the original tube 20, and the outer peripheral surface of the grinding rod is turned to the inner peripheral surface 21 a of the thickened portion 21 of the original tube 20 while rotating around the axis. By making contact, the convex portions 5 and 6 can be cut together with the thickened portion 21.

  Here, the raw tube 20 manufactured in the raw tube manufacturing process without forming the thickened portion 21 on the end 20b side of the original tube 20 in the thickened portion forming step (the original tube 20 shown in FIGS. 3 and 4). On the other hand, it is also conceivable that only the convex portions 5 and 6 are cut and the end portion 20b side of the original tube 20 is formed in a cylindrical shape without the convex portions 5 and 6. However, in this case, there is a high possibility of cutting the tube body of the original tube 20 (the portion that becomes the receiving port 4 of the protective tube main body 1) together with the convex portions 5 and 6, and the end 20b side of the original tube 20 is There is a risk of partial thinning. On the other hand, by forming the thickened portion 21 on the end 20b side of the original tube 20 in the thickened portion forming step as in this embodiment, and cutting the convex portions 5 and 6 together with this thickened portion 21, A desired thickness can be secured and the end 20b side of the original tube 20 can be easily cut, and the end 20b side of the original tube 20 can be partially thinned.

  In this way, at the stage where the end 20b side of the original tube 20 is cut in the cutting step, as shown in FIG. 7, the end 20b side of the original tube 20 is heated and softened, and the original tube is appropriately used. The diameter of the end portion 20b side of 20 is increased, and the receiving port 4 including the enlarged diameter portion 7 and the joint portion 8 is formed (receiving port forming step). At this time, for example, an inner mold and an outer mold corresponding to the shape of the receiving port 4 are used, the inner mold is inserted into the inner hole on the end 20b side of the original tube 20, and the outer mold is set to a predetermined outside the original tube 20. Install in position. Then, the inner mold is expanded (moved) outward in the radial direction of the original tube 20, the diameter is increased while pressing the end 20 b side of the original tube 20 outward, and the end 20 b of the original tube 20 is connected to the outer mold. The receiving port 4 can be formed by sandwiching.

  Thereby, it forms in the substantially cylindrical shape without providing the convex parts 5 and 6 in the end part 1c side of the protective tube main body 1 provided with a pair of convex parts 5 and 6 for attaching the separator 2, and the cable protective pipe A The manufacture of the protective tube main body 1 (cable protective tube A) formed by integrally molding the receiving port 4 for connecting them to each other is completed.

  Therefore, in the cable protection tube A and the manufacturing method of the cable protection tube A of the present embodiment, the receiving port 4 formed in a cylindrical shape without the convex portions 5 and 6 (a cylindrical shape without the convex portions 5 and 6 (cylinder) Shape)) 4) is integrally formed on the end 1c side of the protective tube body 1, so that the protective tube body and the receiving tube are manufactured separately as in the conventional cable protective tube. It becomes unnecessary to connect to the protective tube body, and it becomes possible to improve productivity. Further, since the receiving port 4 is integrally formed, the cables 13 and 15 are not caught at the joint between the protective tube main body and the receiving tube as in the prior art, and the insertion of the cables 13 and 15 can be improved. It becomes possible, and it becomes possible to prevent damage to the cables 13 and 15 reliably.

  Furthermore, in the manufacturing method of the cable protection tube A of the present embodiment, the thickened portion 21 is formed on the inner peripheral surface 20a on the end 20b side of the original tube 20 in the thickened portion forming step, and together with this thickened portion 21 By cutting the convex portions 5 and 6, it is possible to surely prevent the end 20b side of the original tube 20 from being partially thinned, ensuring a desired thickness, and the end 20b of the original tube 20 It becomes possible to cut the side. Thereby, it becomes possible to manufacture the protective tube main body 1 and the cable protective tube A accurately and suitably.

  As mentioned above, although one embodiment of the cable protection tube and the manufacturing method of the cable protection tube according to the present invention has been described, the present invention is not limited to the one embodiment described above, and can be changed as appropriate without departing from the scope of the present invention. Is possible.

1 Protection tube body 1a Internal space (inside)
1b Inner peripheral surface 1c One end (end)
1d Other end portion 2 Separator 2a Plate-like portion 2b Locking portion 2c Locking portion 3 Protective tube portion 3a One end portion 3b Inner peripheral surface 3c Other end portion 4 Receiving port (receiving port portion)
4a Inner peripheral surface 4b One end 4c Other end 5 Convex part 6 Convex part 7 Expanded part 8 Joint part 9 Sealing material fitting groove 10 Upper space 11 Lower space 12 Concave 13 Trunk cable (cable)
14 Sheath tube 15 Pull-in cable (cable)
16 O-ring (sealing material)
20 Original pipe 20a Inner peripheral surface 20b End 21 Increased thickness part 21a Inner peripheral surface A Cable protection pipe O1 Axis line

Claims (1)

A cylindrical protective tube body that protrudes inward from the inner peripheral surface and has a convex portion extending in the axial direction, and a plate-shaped separator that is inserted and installed in the protective tube main body with the concave portion engaged with the convex portion A cable protection tube configured to accommodate a cable in an internal space of the protection tube main body partitioned by the separator,
An original tube manufacturing process for manufacturing an original tube having the convex portion on the inner peripheral surface by extrusion molding,
A thickened part forming step of forming a thickened part so as to embed the convex part by performing a thickening process on the inner peripheral surface on the end side of the original pipe,
Cutting the convex portion together with the thickened portion to make the end side of the original tube have a predetermined thickness; and
A receiving port forming step of heating and softening the end side of the original tube and expanding the diameter to form a receiving port;
The protection tube main body is manufactured by integrally forming the receiving port for connecting the cable protection tubes to each other on the end portion side without forming the convex portion. Manufacturing method of cable protection tube.

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