JP2021158911A - Pipe line of double-wall corner type wiring pipe, pipe line of corner shape wiring pipe, and method of adjusting length of pipe line of the double-wall corner type wiring pipe - Google Patents

Abstract

To provide a pipe line or the like, of double-wall corner type wiring pipe, capable of preventing damages due to a pressure at a time of an expansion of a water expansion nonwoven fabric while securing a high cut-off performance with a simple structure.SOLUTION: An inner connector 1a includes: a cylinder part 3a which is made of, for example, a resin, and has a helical crest part 7a; and a flange part 5a expanded substantially perpendicularly from a pipe end part of the cylinder part 3a to one end part of the cylinder part 3a. A cross sectional shape of the helical crest part 7a in a direction parallel to a pipe shaft direction of the cylinder part 3a is formed by two faced crest parts 11a so as to be separated from each other by a predetermined distance. A separation wall 9a substantially in parallel to the pipe shaft direction, connecting between the crest parts 11a so as to block a groove 13a formed between the faced crest parts 11a is formed in a predetermined interval, and is formed over an upper part of the groove by connecting both of the crest parts in which a water expansion nonwoven fabric 17a provided to the cylinder part 3a is faced.SELECTED DRAWING: Figure 1

Description

INDUSTRIAL APPLICABILITY According to the present invention, a conduit of a double-walled square conduit, a conduit of a square conduit, and a double-walled square conduit in which a double-walled square conduit is connected to a connection structure between a conversion adapter and a hand hole. Regarding the method of adjusting the length of the conduit.

Conventionally, for example, when connecting an electric wire pipe to a hand hole, a connector with a retaining or waterproofing measure is used.

For example, in Patent Document 1, when connecting a cable protection pipe to a pipeline opening member embedded in a wall body such as a hand hole or a manhole, it is easy to assemble various members for taking measures to prevent the cable from coming off and to prevent water from coming off. Moreover, a pipe connection structure that can be reliably performed has been proposed.

In the pipe connection structure of Patent Document 1, one end side of the pipe joint is connected to the conduit opening member, and the cable protection pipe is connected to the other end side of the pipe joint via a functional member for retaining and stopping water. NS. That is, this functional member is fitted to the end of the cable protection tube. The functional member has a fitting cylinder portion that is fitted to the other end side of the pipe joint when the cable protection pipe is connected. Further, the functional member is integrally formed in the fitting cylinder portion, and is provided on the fitting cylinder portion with a retaining material for preventing the cable protection pipe from coming off from the pipe joint when the cable protection pipe is connected. The cable protection pipe is provided with a water blocking material that stops the connection portion when the cable protection pipe is connected.

Further, Patent Documents 2 and 3 propose a pipe body connection structure including a water blocking material that stops water at the connecting portion when the cable protection pipe is connected.

The pipe joint of Patent Document 2 has a joint portion to be coupled to the outer peripheral surface of the pipe body, and also has a contact surface that abuts around the through hole to be connected. Further, the bell mouth has a connecting portion that is bonded to the inner peripheral surface of the tube body, and also has a contact surface that abuts around the through hole to be connected. At this time, a protrusion that enters the through hole is formed at a portion on the inner peripheral side of the contact surface of the pipe joint and on the outer peripheral side of the joint portion. By forming a cylindrical protrusion that fits into the through hole in the pipe joint in this way, in Patent Document 2, the contact surface of the pipe joint is prevented from being displaced in a direction away from the periphery of the through hole. can do.

Further, the pipe joint of Patent Document 3 has a female screw screwed to the outer peripheral surface of the pipe body on the inner peripheral surface as in Patent Document 2, and has an outer cylinder portion that fits into the outer peripheral surface of the pipe body and the outer cylinder. It is provided with an outer surface flange portion having a contact surface that projects in the outer peripheral direction at one end in the axial direction of the portion and abuts on the periphery of the through hole to be connected. Further, the bell mouth has a male screw screwed to the inner peripheral surface of the tube body on the outer peripheral surface, and the inner cylinder portion inserted into the tube body and one end of the inner cylinder portion in the axial direction project in the outer peripheral direction. It is provided with an inner flange portion having an abutting surface that abuts around the through hole.

Further, in Patent Document 3, a pipe outer water expansion portion that expands by absorbing water is formed on the inner peripheral surface of the outer cylinder portion of the pipe joint, and water absorption is performed on the outer peripheral surface of the inner cylinder portion of the bell mouth. A water expansion portion in the tube that expands is formed. By forming the water expansion portion in this way, it is possible to obtain a connection structure capable of obtaining sufficient water stopping while the connection work is easy.

JP-A-2009-159742 Japanese Unexamined Patent Publication No. 2014-207752 Japanese Unexamined Patent Publication No. 2018-031412

However, in the pipe body connection structure of Patent Document 1, the shape of the opening of the pipeline opening member into which the pipe joint is inserted is complicated, and it is difficult to process the conduit opening member.

On the other hand, the structure of Patent Document 2 has a simpler structure as a whole than that of Patent Document 1, and in order to ensure water stopping, the inner peripheral portion of the outer peripheral pipe joint, the back surface of the outer flange portion, and the bell mouth Water-expandable non-woven fabrics are provided on the outer periphery of the inner cylinder portion and the surface of the inner flange portion, respectively. However, the structure of Patent Document 2 is also complicated because the pipe joint on the outer peripheral side has a protrusion that enters the through hole, and the through hole must be enlarged by the amount of the protrusion that enters the through hole. There is a problem that does not become.

Further, Patent Document 3 has a structure similar to that of Patent Document 2, but the structure is simple because there is no protrusion that enters the through hole, and the diameter of the through hole does not need to be unnecessarily increased. good. However, in such a conduit connection structure, the conduit and the like are deformed due to the earth pressure at the time of backfilling the earth and sand after the construction of the bell mouth, and as a result, the water stopping property is lowered and the groundwater becomes an electric wire. There is a risk of intrusion into the inside of pipes, etc. In particular, such a problem becomes remarkable when the tube has a large diameter.

15 (a) and 15 (b) are schematic views showing a conventional connection structure. A through hole 124 is formed in the wall portion 125 of the hand hole 123. The tip of the spiral conduit 121 is inserted into the through hole 124. At this time, outside the hand hole 123, the outer connector 101b is attached to the outer periphery of the spiral conduit 121.

The outer connector 101b has an enlarged flange portion on one end side (hand hole 123 side). Further, a spiral shape is formed on the inner surface of the outer connector 101b to be screwed with the spiral shape on the outer peripheral surface of the spiral conduit 121, and the outer connector 101b is screwed on the outer surface of the spiral conduit 121. At this time, a water-expandable non-woven fabric is arranged on the inner surface of the outer connector 101b, and the outer connector 101b and the spiral conduit 121 are screwed together via the water-expandable non-woven fabric.

On the other hand, the inner connector 101a has an enlarged flange portion on one end side (hand hole 123 side). Further, the inner connector 101a has a spiral shape on the outer peripheral surface, which is screwed with the spiral shape on the inner surface of the spiral conduit 121. A water-expandable non-woven fabric is arranged on the outer peripheral surface of the inner connector 101a (the figure is a perspective view of the water-expandable non-woven fabric).

First, as shown in FIG. 15A, the inner connector 101a is screwed into the tip of the spiral conduit 121 inserted through the through hole 124 (arrow P in the drawing). Next, as shown in FIG. 15B, by tightening the outer connector 101b (arrow Q in the figure), the flange portion of the inner connector 101a and the flange portion of the outer connector 101b form a wall of the hand hole 123. The portion 125 can be sandwiched. As described above, the spiral conduit 121 is connected to the hand hole 123.

FIG. 16 is a cross-sectional view of a connection structure between the spiral conduit 121 and the hand hole 123. As described above, the spiral ridge 107a on the outer surface of the inner connector 101a is screwed with the spiral shape of the spiral conduit 121 inside the spiral conduit 121. Further, the spiral mountain portion 107b on the inner surface of the outer connector 101b is screwed with the spiral shape of the spiral conduit 121 outside the spiral conduit 121.

17 (a) is an enlarged view of the R portion of FIG. 16, and FIG. 17 (b) is an enlarged view of the S portion of FIG. As shown in FIG. 17A, a water-expandable non-woven fabric 117a is arranged on the outer peripheral surface of the inner connector 101a. Further, as shown in FIG. 17B, a water-expandable non-woven fabric 117b is arranged on the inner peripheral surface of the outer connector 101b. Therefore, when water enters the gap between the outer connector 101b and the spiral conduit 121 from the surroundings, the water-expandable non-woven fabric 117b expands, and water stoppage can be ensured. Further, when water enters the gap between the inner connector 101a and the spiral conduit 121, the water-expandable non-woven fabric 117a expands to ensure water stoppage.

In this state, earth and sand are backfilled around the hand hole 123, and a spiral conduit 121 is buried. For example, the spiral conduit 121 is buried at a depth in the range of about 30 cm to 5 m from the ground (usually, in many cases, about 30 cm to 2 m), although it varies depending on the site where it is applied.

At this time, as shown in FIG. 18, when the spiral conduit 121 is laid and then backfilled with earth and sand, the spiral conduit 121 is subjected to the earth pressure at the time of backfilling the earth and sand and when the truck or the like is passing above. It may be loaded (arrow T in the figure). When such earth pressure is applied, the gap between the spiral conduit 121 and the inner connector 101a and the outer connector 101b may increase due to deformation of the spiral conduit 121 or the like. Here, if the burial depth is shallow, the earth pressure is low, but the pressure when a vehicle such as a truck is passing is large. On the contrary, if the burial depth is deep, the earth pressure will be high, but the pressure when the vehicle is passing will be small because it is dispersed in the surrounding ground.

As described above, the water-expandable non-woven fabrics 117a and 117b are arranged between the spiral conduit 121 and the inner connector 101a and the outer connector 101b, but the gap is large due to the deformation of the spiral conduit 121 and the like. Then, it becomes difficult to completely secure the water-stopping property by expanding the water-expandable non-woven fabrics 117a and 117b. Therefore, the water stopping property is lowered, and the groundwater may infiltrate into the hand hole 123 and the spiral conduit 121. This tendency is particularly large for the large-diameter spiral conduit 121.

As a countermeasure against this, there is a method of designing the clearance between the spiral conduit 121 and the inner connector 101a and the outer connector 101b to be small in advance. However, if the clearance between the spiral conduit 121 and the inner connector 101a and the outer connector 101b is too small, the pressure due to the expansion of the water-expandable non-woven fabrics 117a and 117b may become too large.

For example, as shown in FIG. 17A, if the clearance between the spiral conduit 121 and the inner connector 101a is too small, the pressure when the water-expandable non-woven fabric 117a expands (U in the figure) causes the inner connector 101a to expand. And the spiral conduit 121 may be damaged. Similarly, as shown in FIG. 17B, if the clearance between the spiral conduit 121 and the outer connector 101b is too small, the outer connector is affected by the pressure (V in the figure) when the water-expandable conduit 117b expands. There is a risk of damaging 101b and the spiral conduit 121, which may actually be damaged.

As described above, if the clearance between the spiral conduit 121 and the inner connector 101a and the outer connector 101b is reduced in order to prevent deterioration of water stopping property due to the influence of earth pressure or the like, there is a risk of damage to both. Therefore, damage to the spiral conduit 121, the inner connector 101a and the outer connector 101b can be suppressed due to the expansion pressure of the water-expandable non-woven fabrics 117a and 117b, and the connection structure having excellent water stopping property and the like can be suppressed. Is required.

The present invention has been made in view of such a problem, and at the same time as providing a partition wall at the mountain portion of the threaded portion of the connector, it is possible to deform and move the water-expandable non-woven fabric that has been further absorbed and swollen and gelled. By providing a groove between the peaks as a moving space to relieve stress, it is possible to secure high water stopping property with a simple structure and prevent damage due to pressure during expansion of the water-expandable non-woven fabric. Double wall square conduit with double wall square conduit connected to the connection structure of conversion adapter and hand hole, square conduit conduit and double wall square type It is an object of the present invention to provide a method for adjusting the length of a conduit of an electric conduit.

In order to achieve the above-mentioned object, the first invention is a double-walled square electric wire pipe line composed of an outer pipe and a straight tubular inner pipe arranged inside the outer pipe. The heavy-walled square wire tube is connected to the hand hole via a conversion adapter, and the conversion adapter is a joint of a square wire tube from a spiral portion attached to the hand hole using an inner connector and an outer connector. The conversion adapter is composed of a joint portion of the spiral portion formed on one side and a square electric wire tube formed on the other side, and both the inner connector and the outer connector are The cross section is substantially T-shaped, and there is a tubular portion having a spiral mountain portion and a flange portion at one end of the tubular portion that expands in diameter substantially perpendicular to the pipe end portion of the tubular portion. A water-expandable non-woven fabric is provided on the outer peripheral surface of the tubular portion of the inner connector, and rubber packing and a water-expandable non-woven fabric are attached to the inner surface of the flange portion of the inner connector in this order. A water-expandable non-woven fabric is provided on the inner peripheral surface of the tubular portion of the above, and a rubber packing and a water-expandable non-woven fabric are attached to the outer surface of the flange portion of the outer connector in this order. The water-expandable non-woven fabric on the inner surface of the flange portion of the inner connector abuts on the inner wall surface of the hand hole by being screwed into the inner peripheral surface of the end portion of the spiral portion, and the outer connector is formed on the spiral portion. The water-expandable non-woven fabric on the outer surface of the flange portion of the outer connector comes into contact with the outer wall surface of the hand hole, and the flange portion of the inner connector and the flange portion of the outer connector come into contact with each other. , The wall portion of the hand hole is sandwiched, and the cross-sectional shapes of the inner connector or at least one of the outer connectors of the tubular portion in the direction parallel to the tube axis direction are separated from each other by a predetermined distance. A partition wall is formed at a predetermined interval, which is composed of two mountain portions facing each other and is substantially parallel to the pipe axis direction connecting the mountain portions so as to close the groove formed between the mountain portions facing each other. The water-expandable non-woven fabric provided in the tubular portion is formed so as to straddle the upper portion of the groove formed between the mountain portions, and the joint portion of the conversion adapter has the double wall square shape. It is a double-walled square electric wire pipe line, characterized in that the electric wire pipe is connected. Here, in the conduit of the double-walled square conduit, the outer tube and the inner tube of the double-walled square conduit connected to the joint portion of the conversion adapter are mutual at least in a part. It is desirable that they are fused and integrated. In the present invention, in all of the following inventions, the definition of a hand hole includes, in addition to the hand hole, a small branch basin having substantially the same structure as the hand hole, or is interpreted synonymously. And. In the present invention, the description of the rubber packing is described as a typical example of the elastic body used for the rubber packing, and rubber or an elastomer can be preferably used. As the elastomer, both thermosetting elastomers and thermoplastic elastomers can be applied.

The double-walled square electric wire pipe is formed from a male joint portion and a female joint portion formed at both ends of the outer pipe, and a main body portion connecting both the male joint portion and the female joint portion. The main body is formed by alternately and repeatedly forming a substantially cylindrical small diameter portion and a substantially rectangular large diameter portion having a larger diameter, and further, the straight tubular inner tube has a substantially cylindrical shape. The outer surface of the inner pipe may be fused to each other at the inner surface of the outer pipe and the small diameter portion of the outer pipe.

In the male joint portion, the inner pipe is either housed and covered inside the male joint portion or integrated with the inner surface near the tip portion of the male joint portion, and the female The mold joint portion may be cut so as not to obstruct the connection with the male joint portion.

In the conduit of the double-walled square electric conduit, the cross-sectional shapes of the inner connector and the tubular portion of the outer connector in the direction parallel to the pipe axis direction of the spiral mountain portion are mutually predetermined. The partition walls, which consist of two mountain portions facing each other at a distance apart and are substantially parallel to the pipe axis direction connecting the mountain parts so as to close the groove formed between the mountain portions facing each other, are spaced apart from each other at a predetermined distance. The water-expandable non-woven fabric formed in the tubular portion may be formed so as to straddle the upper portion of the groove formed between the mountain portions.

In the conduit of the double-walled square electric wire tube, the partition wall parallel to the pipe axis direction connecting the inner connector and the mountain portion of the spiral mountain portion of the outer connector is the circumferential direction of the spiral mountain portion. It is desirable that the wires are provided at predetermined intervals of 30 ° to 90 °. Sufficient water stopping and rigidity of the mountain portion can be ensured by providing the partition wall at a predetermined interval of 30 ° to 90 ° in the circumferential direction from the start position or the end position of the mountain portion.

In the conduit of the double-walled square electric conduit, the partition wall parallel to the pipe axis direction connecting the spiral ridges of the inner connector and the outer connector between the ridges is perpendicular to the pipe axis direction. It is desirable that a plurality of tubes are formed substantially parallel to a predetermined center line in a direction substantially perpendicular to the predetermined center line at predetermined intervals. If the partition walls are formed at predetermined intervals in the range of 1/2 to 1/5 of the radius vertically with the center in the direction perpendicular to the pipe axis direction, sufficient water stopping property and rigidity of the mountain portion Can be secured. The partition wall is not limited to the conduit of the double-walled square conduit, and can be similarly applied to a single-walled square conduit having no inner tube.

In the conduit of the double-walled square conduit, the joint portion of the conversion adapter is composed of a female joint portion of the square conduit, and the female joint portion is substantially C mounted at a predetermined position. A male joint portion composed of a character-shaped or annular retaining ring and an annular rubber packing may be fitted.

In the conduit of the double-walled square electric conduit, the joint portion of the conversion adapter is composed of a male joint portion of the square electric conduit, and the male joint portion is a predetermined position of the male joint portion. It may be composed of a substantially C-shaped or annular retaining ring and an annular rubber packing mounted on the.

The conversion adapter may have an extra length for adjusting the length of the conversion adapter.

According to the first invention, in the conduit of a double-walled square conduit, the shape of the spiral portion connected to the hand hole is changed to the shape of the joint with the double-walled square conduit. Because it is a conversion adapter for converting the above, it has good water-stopping properties for the conduit of double-walled square conduit, and it is deformed or absorbs water due to soil pressure of the spiral part, inner connector or outer connector. It is possible to suppress damage caused by. As a result, by using a conversion adapter for converting the shape of the joint with the double-walled square-type conduit, a handhole with excellent water-stopping effect is obtained for the double-walled square-type conduit. Can have a connection structure of.

Further, in the cross section in the direction parallel to the pipe axis direction, the cross-sectional shape of at least one of the spiral ridges of the inner connector or the outer connector is composed of two ridges facing each other at a predetermined distance from each other. A groove is formed in. Therefore, when the water-expandable non-woven fabric absorbs water and swells and expands, the excessive expansion of the water-expandable non-woven fabric can be released to the groove. As a result, excessive stress due to the swollen and gelled water-expandable non-woven fabric between the spiral portion and the inner connector or the outer connector can be relieved, and damage to the member can be suppressed.

In addition, partition walls connecting the peaks are formed at predetermined intervals between the facing peaks so as to close the grooves in parallel with the pipe axis direction, so that the grooves serve as a water intrusion route. It can be suppressed. Further, by providing a partition wall connecting the two peaks, the rigidity of the two peaks can be increased. In this way, by using an inner connector or an outer connector in which the cross-sectional shape of the spiral mountain portion is composed of two mountain portions facing each other at a predetermined distance from each other, water stoppage is ensured and the inner side is increased by stress due to water absorption and swelling. It is possible to obtain the effect of preventing damage to the connector or the outer connector. As a result, even in the case of a large-diameter double-walled square conduit, it is possible to suppress damage to each member and prevent groundwater from flowing into the double-walled square conduit or the like.

Further, at the tip of the male joint, the inner surface near the tip of the male joint is integrated with the inner pipe, or the inner pipe is covered with the male joint, so that the manufacturing is easy. This makes it easy to connect double-walled square conduits to each other.

In addition, since the inner pipe is cut off on the inner surface of the female joint portion, the male joint portion and the inner pipe inside the female joint portion interfere with each other when mated with the male joint portion. Can be suppressed. As described above, in the case of the male joint, it is not always necessary to cut off the inner pipe, but in the case of the female joint, the insertion of the male joint is obstructed when connecting to the male joint. Therefore, it is necessary to cut off the male joint.

Further, in the conduit of a double-walled square electric conduit, the cross-sectional shapes of both the inner connector and the outer connector in the direction parallel to the pipe axis direction are opposed to each other at a predetermined distance from each other. The above-mentioned effect can be obtained more reliably by forming a partition wall connecting the mountain portions so as to block the groove formed between the two mountain portions facing each other.

Further, it is sufficient that the partition wall is provided so as to connect the mountain portions of the spiral mountain portion and is provided at a predetermined interval of 30 ° to 90 ° in the circumferential direction from the start position or the end position of the mountain portion. Water stoppage and rigidity of the mountain part can be ensured.

Further, partition walls are provided so as to connect the mountain portions of the spiral mountain portion, and a plurality of partition walls are formed substantially in parallel at predetermined intervals between 1/2 and 1/5 of the radius vertically with the center line position in between. If this is done, sufficient water stoppage and rigidity of the mountain portion can be ensured. Here, a plurality of partition walls formed substantially in parallel may or may not be formed at the center line position, but are formed at the center line position as a whole. It is desirable because the partition walls are formed at equal intervals.

Further, the joint portion of the conversion adapter is composed of a female joint portion of a square conduit, and the female joint portion is a substantially C-shaped or annular retaining ring mounted at a predetermined position and an annular rubber packing. If it is possible to connect to the male joint portion composed of the above, it is possible to easily connect to the female joint portion of the square conduit, and it is possible to secure the retaining property and the water stopping property of the connecting portion.

Further, if the joint portion of the conversion adapter is composed of a male joint portion of a square conduit, and the male joint portion is composed of a substantially C-shaped or annular retaining ring and an annular rubber packing, it is square. It can be easily connected to the female joint portion of the electric conduit, and it is possible to secure the retaining property and water stopping property of the connecting portion.

Further, if the conversion adapter has an extra length portion for adjusting the length of the spiral portion, the length of the conversion adapter can be adjusted according to the length of the square conduit to be connected. .. Therefore, a pipeline having a desired pipeline length can be easily constructed. In particular, it is effective for finely adjusting the length in front of the junction box.

It should be noted that the cross-sectional shapes of the spiral ridges of both the inner connector and the outer connector in the direction parallel to the tube axis direction form two ridges facing each other at a predetermined distance from each other. Further, as described above, partition walls connecting the mountain portions are formed at predetermined intervals so as to close the grooves in parallel with the pipe axis direction, so that the grooves can enter the water. Can be suppressed. Further, by providing a partition wall connecting the two peaks, the rigidity of the two peaks can be increased. In this way, by using an inner connector or an outer connector in which the cross-sectional shape of the spiral ridge is composed of two ridges facing each other at a predetermined distance from each other, water stoppage is ensured and damage is caused by stress increase due to water absorption and swelling. It is possible to obtain any effect of prevention. As a result, in the conduit of the double-walled square conduit having a connection structure between the large-diameter conversion adapter and the hand hole, damage to each member is suppressed and the double-walled square conduit can be connected to the conduit. It is possible to prevent the inflow of groundwater.

The second invention is parallel to the pipe axis direction connecting the inner connector and the spiral mountain portion of the outer connector between the mountain portions in the conduit of the double-walled square electric conduit according to the first invention. A plurality of the partition walls are formed in a direction perpendicular to the pipe axis direction, substantially parallel to the center line at a predetermined position at a predetermined interval in a direction substantially perpendicular to the center line, and vertically at a predetermined interval with the center line position and the center line in between. A conduit of a square conduit formed and characterized in that a square conduit having no inner pipe is connected to the joint portion of the conversion adapter instead of the double-walled square conduit. be.

In this case, the partition walls formed in a plurality of substantially parallel directions at the predetermined intervals are vertically between the center line position and the center line and between 1/2 and 1/5 of the radius in the direction perpendicular to the pipe axis direction. It may be formed at predetermined intervals.

In this way, in the cross section perpendicular to the pipe axis direction, the inner connector and the outer connector formed in a direction substantially perpendicular to the center line at a predetermined position and substantially parallel to each other at a predetermined interval are two. It can be applied not only to heavy-walled conduits but also to square conduits that do not have ordinary inner tubes. This is because such a structure facilitates the manufacture of the mold without forming the mold for manufacturing these products into another divided structure.

The third invention is to fine-tune the conduit length with respect to the conduit of the double-walled square conduit using at least a part of the conduit of the double-walled square conduit of the first invention. This is a method for adjusting the length of a conduit of a double-walled square electric conduit, which is performed by cutting the conversion adapter. Especially in the case of double-walled square conduit, it is often the case that a standard-sized pipe with a length of about 5 m is connected to form a conduit, and fine adjustment of the conduit length of the double-walled square conduit is converted. It can be easily done by adjusting the length by disconnecting the adapter.

According to the third invention, the length of the pipeline can be finely adjusted by cutting the extra length portion of the conversion adapter, so that the pipeline having a desired pipeline length can be easily constructed. .. In particular, if this adjustment method is used, fine adjustment of the pipeline length in the vicinity of the hand hole becomes easy.

According to the present invention, a connection structure between a conversion adapter and a hand hole can ensure high water stopping property with a simple structure and can prevent damage due to pressure during expansion of the water-expandable non-woven fabric. It is possible to provide a method for adjusting the length of a conduit of a double-walled square conduit, a conduit of a square conduit, and a conduit of a double-walled square conduit to which a double-walled square conduit is connected. can.

(A) is a side view of the inner connector 1a, and (b) is a front view of the inner connector 1a (a perspective view of the spiral mountain portion 7a). (A) is a cross-sectional view of the spiral ridge 7a, (b) is a cross-sectional view of the spiral ridge 7a on the partition wall 9a, and (c) is a cross-sectional view of another form of the spiral ridge 7a. (A) is a side view of the inner connector 1aa, and (b) is a front view of the inner connector 1aa (a perspective view of the spiral mountain portion 7a). A side view of an inner connector 1a to which a water-expandable non-woven fabric 17a or the like is attached. (A) is a cross-sectional view of the outer connector 1b, and (b) is a front view of the outer connector 1b (a perspective view of the spiral mountain portion 7b). A side view of an outer connector 1b to which a water-expandable non-woven fabric 17b or the like is attached. (A) is a side view showing a double-walled square electric conduit 40, and (b) is a cross-sectional view of (a). (A) is a cross-sectional view showing a connection structure between a male joint portion 41 and a female joint portion 43 of a double-walled square electric conduit, and (b) is an enlarged view of the AA portion of (a). (A) is a diagram showing a conversion adapter 60a, and (b) is a diagram showing a conversion adapter 60b. FIG. 2 is a cross-sectional view showing a connection structure 20a in which a hand hole and a conversion adapter 60a are connected. It is a figure which shows the morphology at the time of expansion of the water-expandable nonwoven fabric 17a in the spiral mountain part 7a, (a) is the sectional view parallel to the tube axis direction, (b) is the sectional view perpendicular to the tube axis direction. (A) and (b) are diagrams showing a process of constructing a conduit 30b of a double-walled square electric conduit. (A) and (b) are diagrams showing a process of constructing a conduit 30c of a double-walled square electric conduit. It is a figure which shows the method of adjusting the length by the extra length part 65 of the conversion adapter 60a, and connecting with a double-walled square electric wire tube 40. (A) and (b) are diagrams showing a process of connecting a spiral conduit to a hand hole 123 by using a conventional inner connector 101a and an outer connector 101b. FIG. 5 is a cross-sectional view of a state in which a spiral conduit is connected to a hand hole 123 using a conventional inner connector 101a and an outer connector 101b. (A) is an enlarged view of the R portion of FIG. 16, and (b) is an enlarged view of the S portion of FIG. The figure which shows the state which earth pressure was applied to the spiral conduit 121 from above.

(Inner connector)
Hereinafter, the members used in the embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a side view of the inner connector 1a, and FIG. 1B is a view taken along the line W of FIG. 1A, which is a perspective view of the spiral mountain portion 7a. The inner connector 1a is a member used for connecting a spiral conduit as shown in FIG. 15 and a spiral portion of a conversion adapter (FIG. 9) described later to a hand hole, and together with an outer connector described later. Used.

The inner connector 1a is made of, for example, a resin, and has a cylindrical portion 3a having a spiral crest portion 7a and a flange at one end of the tubular portion 3a that expands in diameter substantially at a right angle from the pipe end portion of the tubular portion 3a. It has a part 5a. That is, the inner connector 1a is a member having a substantially T-shaped cross section. The spiral ridge portion 7a of the inner connector 1a is a portion that protrudes from the outer surface of the tubular portion 3a, and is to be screwed into the outer surface of the cylindrical portion 3a of the inner connector 1a with a spiral portion such as a conversion adapter. Is formed in.

FIG. 2A is an enlarged cross-sectional view of the spiral mountain portion 7a. The cross-sectional shape of the spiral mountain portion 7a in the direction parallel to the pipe axis direction of the tubular portion 3a is composed of two mountain portions 11a facing each other at a predetermined distance from each other. Further, as shown in FIGS. 1 (b) and 2 (b), the mountain portions 11a are connected so as to close the groove 13a formed between the opposing mountain portions 11a, and the mountain portions 11a are substantially parallel to the pipe axis direction. Partition walls 9a are formed at predetermined intervals. The more the partition wall 9a is, the more surely the water-stopping effect and the rigidity improving effect can be obtained. However, if the number of the partition walls 9a is increased too much, the effect of relaxing the pressure at the time of expansion of the water-expandable non-woven fabric is reduced.

The arrangement interval θa in the circumferential direction of the partition wall 9a (see FIG. 1B) is set in order to obtain a good balance of a water blocking effect, a rigidity improving effect, and a damage prevention effect due to pressure during expansion due to water absorption of the water-expanding non-woven fabric. Is preferably in the range of 30 ° to 90 °, but can be in the range of up to 20 ° to 90 °. Further, as will be described later, the arrangement direction of the partition wall 9a does not necessarily have to be toward the center direction. For example, the direction may be parallel to the partition line of the mold or the same direction as the separation direction of the mold used at the time of molding.

More specifically, the partition wall is located at a predetermined range of 30 ° to 90 ° in the circumferential direction from the spiral start position or spiral end position of the spiral mountain portion 7a, starting from these start points or end points. It is desirable that 9a is formed. However, in order to suppress the intrusion of water into the groove 13a between the mountain portions 11a and increase the rigidity of the end portion of the mountain portion 11a, the first partition wall 9a and the last partition wall 9a are spiral mountain portions. It is desirable to provide it near the start position or the end position of 7a.

Here, as shown in FIG. 2A, in a cross section parallel to the pipe axis direction of each of the two mountain portions 11a, the angle θo of the outer ridge line of each mountain portion 11a with respect to the pipe axis direction is the angle of the inner ridge line. It is formed smaller than θi. Further, the length Y of the outer support portion of the base portion of the mountain portion 11a passing through the apex of each mountain portion 11a and being divided by the line O perpendicular to the pipe axis direction is the length of the inner support portion. Longer than Z.

The cross-sectional shape of the mountain portion 11a is not limited to the illustrated example. For example, in the illustrated example, both the outer ridge line and the tip end portion of the inner ridge line of the mountain portion 11a are composed of curved lines, but one of them may be linear. For example, the tip of the outer ridge may be curved, and the inner ridge may be a straight mountain.

Further, in the example shown in FIG. 2A, the mountain portion 11a shows an example in which the cross section of the protruding mountain portion shape is solid, but the present invention is not limited to this. For example, as shown in FIG. 2C, in the cross section, the outer surface and the inner surface of the mountain portion 11a may both be formed into a protruding wavy shape and have a recessed portion on the inner surface. Here, it is desirable that the mountain portion 11a has a solid cross section in the shape of a protruding mountain portion. The reason for this is that if the cross section of the protruding mountain portion is solid, the rigidity of the cylindrical portion 3a of the inner connector 1a is improved. As a result, the effect of preventing water leakage from the hand hole 23 due to the effect of preventing deformation of the cross section of the tubular portion 3a of the inner connector 1a is improved, the effect of preventing creep deformation when earth pressure is applied for a long period of time, and the effect of forming the connector. Has excellent dimensional stability. In the following description, the case where the mountain portion 11a is solid will be described.

FIG. 3A is a side view of the inner connector 1aa, and FIG. 3B is a view taken along the line AB of FIG. 3A, which is a perspective view of the spiral mountain portion 7a. The inner connector 1aa has substantially the same configuration as the inner connector 1a, but the form of the partition wall 9a is different. Unlike the inner connector 1a, the inner connector 1aa does not have a partition wall 9a formed in the radial direction from the center, but has a cross section perpendicular to the pipe axis direction with respect to the center line (diameter) at a predetermined position. , The partition walls are formed substantially parallel to each other at predetermined intervals in a substantially vertical direction.

Here, instead of forming the partition walls 9a evenly in the circumferential direction as in the inner connector 1a, the partition walls 9a are substantially parallel to a predetermined center line (diameter) in a direction substantially perpendicular to the predetermined intervals. By doing so, the mold for molding this product is not divided into multiple parts in the circumferential direction, but the inner connector with two molds that are symmetric with respect to the predetermined center line. This is because it becomes possible to manufacture. That is, by setting the center line at a predetermined position as the partition line of the mold, the direction is perpendicular to the partition line of the mold for molding the inner connector 1aa (that is, the separation direction of the mold used at the time of molding). A partition wall 9a can be provided.

As for the arrangement of the partition wall 9a, for example, the partition wall 9a may or may not be arranged at the position of the center line (center line AC divided into the left and right in FIG. 3B) in the left-right direction. In any case, a predetermined number of lines are arranged symmetrically with respect to the center line and substantially parallel to the center line at predetermined intervals in the vertical direction. Here, the length of each partition wall 9a provided in the vertical direction becomes longer as the distance from the center line in the vertical direction (center line AD divided into upper and lower parts in FIG. 3B) increases, and the center line AD becomes longer. The partition wall 9a farthest from is the longest. Normally, the partition wall 9a is provided so as to connect the inner and outer spiral mountain portions 7a, but the partition wall 9a farthest from the center line AD has an outer spiral shape as shown in FIG. 3 (b). It may be provided so as to connect the mountain portions 7a to each other.

In the illustrated example, 12 places are formed symmetrically in the vertical direction around the partition wall 9a passing through the center line AD in the vertical direction. The partition wall 9a located at the position farthest from the center line AD is arranged so as to connect the outer spiral mountain portions 7a to each other. Further, at the center of the partition wall 9a located at the position farthest from the center line AD, another partition wall 9a substantially perpendicular to the center line AD is provided. The vertical partition wall 9a cannot be provided at an arbitrary position, but the forming position of the vertical partition wall 9a hinders the division of the mold in order to correspond to the partition line forming position of the mold. There is nothing to do.

It should be noted that the intervals of the plurality of partition walls 9a formed substantially parallel to each other at predetermined intervals in the vertical direction may be formed at predetermined intervals. For example, the plurality of partition walls 9a have a radius of 1/2 to 1/5, that is, a diameter of 1/4 to 1/10 of the center line AD that divides the center line AD into two in the vertical direction. It suffices if they are formed at predetermined intervals in the range. Alternatively, a plurality of partition walls 9a formed substantially in parallel at predetermined intervals are vertically 1/3 to 1/5 of the radius, that is, 1/6 to 1/10 of the diameter, with the center line AD position and the center line AD in between. It suffices if it is formed at a predetermined interval between them. Here, the interval at which the partition wall is provided needs to be within a predetermined range in order to obtain the water blocking effect and the rigidity improving effect for suppressing the deformation of the spiral mountain portion. Therefore, as the product size increases, the partition wall is provided. Since it is necessary to provide a large number, it is desirable that the ratio of the formation interval to the diameter and radius of the partition wall be reduced while satisfying the above setting range. In the following description, an example using the inner connector 1a will be described, but the same effect can be obtained with the inner connector 1aa.

FIG. 4 is a diagram showing a usage state of the inner connector 1a, and is a perspective view of a part of the water-expandable non-woven fabric 17a. As shown in the enlarged cross-sectional view of the D portion of FIG. 4, a water-expandable non-woven fabric 17a is provided on the outer peripheral surface of the tubular portion 3a of the inner connector 1a. At this time, the water-expandable non-woven fabric 17a provided in the tubular portion 3a is attached so as to straddle the pair of mountain portions 11a and cover the upper portion of the groove 13a formed between the mountain portions 11a. Therefore, a gap corresponding to the groove 13a is formed between the water-expandable non-woven fabric 17a and the outer surface of the inner connector 1a.

The water-expandable non-woven fabric 17a is preferably a non-woven fabric to which, for example, polyester fibers, sodium polyacrylate fibers, and a binder resin are added. As described above, by using the binder resin, a non-woven fabric in which some of the fibers of the non-woven fabric are adhered to each other by the binder resin and the fibers are connected to each other can be obtained. In this case, the ratio of the polyester fiber and sodium polyacrylate is such that the amount of sodium polyacrylate is 30% by mass to 70% by mass, and more preferably 50% by mass to 70, when the total of both is 100% by mass. It is preferably mass%. Further, in the water-expandable non-woven fabric 17a, it is desirable to use the binder resin in the range of 1 to 10% by mass with respect to the total of both the polyester fiber and the sodium polyacrylate fiber, and more preferably 1% by mass. It is desirable to use in the range of% to 5% by mass. The water-expandable non-woven fabric 17a is preferably molded by, for example, a needle punching method. Here, since the typical polyester resin is PET resin, PET fiber is often used as the polyester fiber used for the non-woven fabric. The method for synthesizing a polyester resin is made by dehydrating and condensing polyalcohol and polyvalent carboxylic acid, and polymerizing the polyalcohol and polyvalent carboxylic acid in an alternately arranged manner.

The water absorption of the water-expandable non-woven fabric 17a is provided by sodium polyacrylate, but since the polymer of acrylic acid has many carboxyl groups, it is extremely hydrophilic and is further crosslinked into a network structure to form a sodium salt. Then, the gel has high water absorption and exhibits excellent water absorption characteristics.

Here, the tubular portion 3a side (arrow B in the figure) of the flange portion 5a of the inner connector 1a is the inner surface side of the flange portion 5a, and the side opposite to the tubular portion 3a of the flange portion 5a (arrow A in the figure). It is on the outer surface side of the flange portion 5a. As shown in the enlarged cross-sectional view of the C portion in FIG. 3, a rubber packing 15a and a water-expandable non-woven fabric 17a are attached to the inner surface of the flange portion 5a of the inner connector 1a in this order as elastic members. That is, the water-expandable non-woven fabric 17a is provided on the rubber packing 15a provided on the inner surface of the flange portion 5a.

(Outer connector)
Next, the outer connector 1b will be described as a member used in the embodiment of the present invention. 5 (a) is a side view of the outer connector 1b, and FIG. 5 (b) is a view taken along the line X of FIG. 5 (a), which is a perspective view of the spiral mountain portion 7b. The outer connector 1b is made of, for example, a resin, and has a cylindrical portion 3b having a spiral crest portion 7b and a flange that expands in diameter at one end of the tubular portion 3b substantially at right angles from the pipe end portion of the tubular portion 3b. It has a part 5b. That is, both the outer connector 1b and the inner connector 1a are members having a substantially T-shaped cross section. The spiral ridge portion 7b of the outer connector 1b is a portion protruding in the central direction on the inner surface of the tubular portion 3b, and the spiral portion such as a conversion adapter and a screw are formed on the inner surface of the cylindrical portion 3b of the outer connector 1b. Formed to fit.

A spiral ridge 7b is provided on the inner surface of the tubular portion 3b, and the cross-sectional shape of the spiral ridge 7b in the direction parallel to the pipe axis is such that the two ridges 11b face each other at a predetermined distance from each other. Consists of. The form of the mountain portion 11b is substantially the same as that of the mountain portion 11a. Similar to the spiral mountain portion 7a of the inner connector 1a described above, the mountain portion 11b may have a solid cross section, or the outer surface and the inner surface of the mountain portion 11b have a similar wavy shape in the cross section. It may have a shape having a recess on the inner surface side.

Further, similarly to the spiral ridge portion 7a of the inner connector 1a, the ridge portions 11b are connected so as to close the groove 13b formed between the ridge portions 11b facing each other, and the partition wall 9b substantially parallel to the pipe axis direction is formed. Are formed at predetermined intervals. The more the partition walls 9b, the more reliable the water blocking effect and the rigidity improving effect. However, if the number of partition walls 9b is too large, the effect of alleviating the deformation due to the pressing force at the time of expansion of the water-expandable non-woven fabric. Therefore, the arrangement interval θb in the circumferential direction of the partition wall 9b (see FIG. 5B) has an effect of stopping water, an effect of improving rigidity, and an effect of alleviating deformation due to a pressing force during expansion of the water-expandable non-woven fabric. In order to obtain a good balance, it is necessary to set it in the range of 20 ° to 90 °, but it is desirable to set it in the range of 30 ° to 90 °.

Similar to the inner connector 1aa described above, the outer connector 1b may be provided with a partition wall 9b parallel to each other. That is, the partition walls 9a and 9b formed parallel to the pipe axis direction so as to connect the spiral mountain portions 7a and 7b of the inner connector and the outer connector are cross sections perpendicular to the pipe axis direction. In the above, a plurality of may be formed substantially parallel to each other at predetermined intervals in a direction substantially perpendicular to the center line at a predetermined position. In this way, in the cross section perpendicular to the pipe axis direction, the inner connector and the outer connector formed in a direction substantially perpendicular to the center line at a predetermined position and substantially parallel to each other at a predetermined interval are two. It can be applied not only to heavy-walled conduits but also to square conduits that do not have ordinary inner tubes.

FIG. 6 is a partial cross-sectional view showing a usage state of the outer connector 1b. A water-expandable non-woven fabric 17b is provided on the inner peripheral surface of the tubular portion 3b of the outer connector 1b. As the water-expandable non-woven fabric 17b, the same one as the water-expandable non-woven fabric 17a can be used. Further, the water-expandable non-woven fabric 17b provided in the tubular portion 3b is attached so as to straddle the pair of mountain portions 11b and cover the upper portion of the groove 13b formed between the mountain portions 11b. Therefore, a gap corresponding to the groove 13b is formed between the water-expandable non-woven fabric 17b and the inner surface of the outer connector 1b.

Similar to the inner connector 1a, the tubular portion 3b side (arrow B in the figure) of the flange portion 5b of the outer connector 1b is the inner surface side of the flange portion 5b, and the side opposite to the tubular portion 3b of the flange portion 5b ( The arrow A) in the figure is the outer surface side of the flange portion 5b. As shown in the enlarged cross-sectional view of the E portion of FIG. 5, the rubber packing 15b and the water-expandable non-woven fabric 17b are attached to the outer surface of the flange portion 5b of the outer connector 1b in this order. That is, the water-expandable non-woven fabric 17b attached to the inner surface of the flange portion 5b is provided on the rubber packing 15b provided on the outer surface of the flange portion 5b.

The inner connector 1a and the outer connector 1b may be collectively referred to as a connector. That is, each of the connectors connected to the conversion adapter or the like has a substantially T-shaped cross section, and is one of a cylindrical portion 3a and 3b having a spiral crest portion 7a and 7b and a tubular portion 3a and 3b. The end portion has flange portions 5a and 5b whose diameter is expanded substantially at right angles from the pipe end portions of the tubular portions 3a and 3b.

At this time, in the case of the inner connector 1a, the water-expandable non-woven fabric 17a is attached to the outer peripheral surface of the tubular portion 3a and the inner surface of the flange portion 5a, and in the case of the outer connector 1b, the inside of the tubular portion 3b. A water-expandable non-woven fabric 17b is attached to the peripheral surface and the outer surface of the flange portion 5b. Further, in any case, the cross-sectional shapes of the spiral ridges 7a and 7b of the tubular portions 3a and 3b in the direction parallel to the pipe axis direction are two ridges 11a and 11b facing each other with a predetermined distance from each other. The partition walls 9a and 9b are connected between the mountain portions 11a and 11b so as to close the grooves 13a and 13b formed between the mountain portions 11a and 11b facing each other, and the partition walls 9a and 9b substantially parallel to the pipe axis direction are spaced apart from each other. Is formed by.

(Structure of double-walled square conduit and square conduit)
Next, the double-walled square electric wire tube 40 will be described as a member used in the embodiment of the present invention. FIG. 7 (a) is a side view showing the double-walled square electric wire tube 40, and FIG. 7 (b) is a cross-sectional view of the double-walled square electric wire tube 40 in the pipe axial direction.

The double-walled square wire conduit 40 is mainly composed of an inner pipe 59, an outer pipe 57, a male joint portion 41, a female joint portion 43, and the like. The double-walled square wire conduit 40 is made of a synthetic resin such as a polyolefin resin. The double-walled square wire tube 40 is composed of an outer tube 57 and an inner tube 59 arranged inside the outer tube 57. The inner pipe 59 has a substantially cylindrical shape, and the outer surface of the inner pipe 59 is integrated with the inner surface of the outer pipe 57 at a position corresponding to the small diameter portion 49 by fusion.

Further, a male joint portion 41 is provided at one end of the outer pipe 57 of the double-walled square electric conduit 40, and a female joint portion 43 is provided at the other end. That is, a male joint portion 41 and a female joint portion 43 are formed at both ends of the outer pipe 57, respectively. The male joint portion 41 and the female joint portion 43 serve as connection portions with other double-walled square electric conduits 40 and the like. That is, the double-walled square wire conduit 40 includes both the male joint portion 41 and the female joint portion 43, and the male joint portion 41 and the female joint portion 43, which are formed at both ends of the outer pipe 57, respectively. It consists of the main body to be connected. In the main body portion connecting the male joint portion 41 and the female joint portion 43, a substantially cylindrical small diameter portion 49 and a substantially rectangular large diameter portion 51 having a larger diameter are alternately and repeatedly formed. The diameter (length of one side) of the large diameter portion 51 is larger than the outer diameter of the small diameter portion 49. Although not particularly shown here, the structure of a square conduit will be described. The square conduit is obtained by removing the inner tube 59 from the double-walled square conduit 40, and since there is no inner tube, there is no fusion portion. The square conduit is composed of only the outer pipe 57, and the outer pipe 57 is composed of a male joint portion 41, a female joint portion 43, and a main body portion connecting the two. The structure of the male fitting part, female fitting part, and main body of the outer tube is exactly the same as that of the double-walled conduit 40, and the main body has a substantially cylindrical small diameter part and a large diameter substantially rectangular large diameter. The diameters are alternately and repeatedly formed.

(Mating of double wall square conduit)
Next, the male joint portion 41 and the female joint portion 43 will be described. The male joint portion 41 and the female joint portion 43 can be fitted to each other. That is, the double-walled square wire tubes 40 can be connected to each other. FIG. 8A is a cross-sectional view showing a connection structure between the male joint portion 41 and the female joint portion 43, and FIG. 8B is an enlarged view of the AA portion of FIG. 8A.

A retaining ring 47 and a rubber packing 45 are arranged at predetermined positions at the ends of the male joint portion 41. The retaining ring 47 is a substantially C-shaped member in which a part in the circumferential direction is cut at a cutting portion. In the retaining ring 47, the claw portion 46 and the slide guide 48 are alternately formed via slits in the circumferential direction. For the retaining ring 47, for example, ABS resin, PP resin, hard vinyl chloride, a mixed resin of any of these and a PC resin, or a polymer alloy can be applied. Although not particularly shown, the retaining ring 47 is not necessarily substantially C-shaped, and has a saw blade-shaped groove, a large number of minute protrusions, an adhesive layer having a release paper, or a locking protrusion at both ends of the ring. An annular ring can also be formed by having a connecting portion such as a locking slit and connecting the connecting portions to each other. As described above, in the present invention, the annular ring can be used instead of the substantially C-shaped ring. That is, both a substantially C-shaped ring and an annular ring can be used.

An annular rubber packing 45 is provided on the base side of the retaining ring 47. The rubber packing 45 is made of, for example, EP rubber, SBR, CR, NBR, ACM rubber, EPDM / PP dynamically crosslinked elastomer, or the like.

As shown in FIG. 8B, one end side of the retaining ring 47 is a reduced diameter portion whose outer diameter is smaller than that of the other portion, and a plurality of diameters are expanded toward the other end side. Claw portion 46 is provided. The diameter of the retaining ring 47 can be reduced by elastic deformation of each claw portion 46.

In the circumferential direction of the retaining ring 47, a slide guide 48 is provided between the claw portions 46 via a slit. The slide guide 48 is formed from the reduced diameter portion substantially parallel to the axial direction of the retaining ring 47. The retaining ring 47 is arranged between the pair of restricting portions 50 in the male joint portion 41. The regulating portion 50 is a portion having an outer diameter larger than the portion where the retaining ring 47 is arranged. The retaining ring 47 can slide between the regulating portions 50 in the axial direction. At this time, the slide guide 48 suppresses the retaining ring 47 from tilting with respect to the axial direction of the male joint portion 41 when the retaining ring 47 slides. Therefore, the retaining ring 47 can be slid smoothly.

The outer shape of the male joint portion 41 is formed by the outer pipe 57. The inner pipe 59 is housed and covered inside the male joint portion 41 in the male joint portion 41. In the male joint portion 41, the inner pipe 59 is integrated with, for example, the inner surface of the tip portion of the male joint portion 41. The inner surface of the male joint portion 41 and the inner pipe 59 may not be integrated, and the inner pipe 59 and the male joint portion 41 may be separated from each other. That is, the male joint portion 41 has an inner surface in the vicinity of the tip portion of the male joint portion 41 integrated with the inner pipe 59, or the inner pipe 59 does not protrude from the tip portion of the male joint portion 41. It does not necessarily have to be contact-fixed as long as it is covered, but it is desirable that it is integrated.

Next, the female joint portion 43 will be described. The female joint portion 43 fits with the male joint portion 41 described above. From the tip side (opening side), the female joint portion 43 has a tubular portion 54, a slope portion 52 whose inner diameter gradually decreases from the tubular portion 54, and a diameter increase from the minimum inner diameter portion of the slope portion 52. The ring fitting portion 53 is provided. The inner pipe 59 is cut off at least a part of the inner surface of the female joint portion 43 so as not to hinder the fitting with the male joint portion 41.

As shown in FIG. 8A, when the male joint portion 41 is pushed into the female joint portion 43, the slope portion 52 of the female joint portion 43 and the retaining ring 47 come into contact with each other, and the claw portion 46 is deformed. The diameter of the retaining ring 47 is reduced. At this time, since the retaining ring 47 can slide between the regulating portions 50, the insertion resistance can be reduced by reducing the diameter and sliding of the retaining ring 47 when the male joint portion 41 is inserted. Further, the slide guide 48 can suppress the inclination of the retaining ring 47 when the retaining ring 47 is slid.

Further, when the male joint portion 41 is pushed in, the end portion of the claw portion 46 passes through the slope portion 52 of the female joint portion 43, and the elastically deformed claw portion 46 is restored to the original diameter and expanded in diameter. .. As a result, the claw portion 46 of the retaining ring 47 is fitted with the ring fitting portion 53 of the female joint portion 43. Therefore, the female joint portion 43 and the male joint portion 41 are connected.

In this state, the outer peripheral surface of the rubber packing 45 is in close contact with the inner surface of the tubular portion 54 of the female joint portion 43, and the gap between the female joint portion 43 and the male joint portion 41 can be filled. Therefore, it is possible to prevent water from entering between the female joint portion 43 and the male joint portion 41 from the outside.

(Conversion adapter)
Next, a conversion adapter will be described as a member used in the embodiment of the present invention. FIG. 9A is a diagram showing a conversion adapter 60a. The conversion adapter 60a has a spiral portion 63 formed on one side and a female joint portion 61a formed on the other side. The female joint portion 61a is a joint portion with the above-mentioned double-walled square electric conduit 40.

The spiral portion 63 has the same form as the spiral conduit 121 described above. Therefore, the inner connector 1a and the outer connector 1b can be screwed into the spiral portion 63. Further, the female joint portion 61a has the same form as the female joint portion 43 described above. Therefore, the male joint portion 41 of the double-walled square wire conduit 40 can be connected to the female joint portion 61a. That is, the conversion adapter 60a can convert the spiral portion 63 into which the inner connector 1a and the outer connector 1b can be arranged to the female joint portion 61a which is a joint portion with the double wall square conduit 40. ..

(Connection structure of conversion adapter to hand hole)
Next, the connection structure of the conversion adapter 60a to the hand hole using the inner connector 1a and the outer connector 1b will be described. FIG. 10 is a cross-sectional view showing a connection structure 20a in which the spiral portion 63 of the conversion adapter 60a is connected to the hand hole 23 by the inner connector 1a and the outer connector 1b. As shown in FIG. 16, the inner connector 1a and the outer connector 1b can be used in the same procedure as the conventional inner connector 101a and outer connector 101b. Therefore, in the following description, some overlapping descriptions will be omitted.

A through hole 24 is formed in the wall portion 25 of the hand hole 23. Outside the hand hole 23, the outer connector 1b is arranged on the outer peripheral surface of the spiral portion 63 of the conversion adapter 60a. The outer connector 1b is screwed onto the outer peripheral surface of the spiral portion 63 of the conversion adapter 60a. At this time, the outer connector 1b is arranged with the flange portion 5b facing the end side of the spiral portion 63 of the conversion adapter 60a. Further, the amount of protrusion of the spiral portion 63 of the conversion adapter 60a from the flange portion 5b side of the outer connector 1b is set to be slightly larger than the thickness of the wall portion 25 of the hand hole 23.

In this state, one end of the spiral portion 63 of the conversion adapter 60a is inserted into the through hole 24. Further, from the inner side of the hand hole 23, the inner connector 1a is screwed and arranged on the inner peripheral surface of one end of the spiral portion 63 of the conversion adapter 60a. In the inner connector 1a, the flange portion 5a (water-expandable non-woven fabric 17a) and the end portion of the spiral portion 63 of the conversion adapter 60a come into contact with each other, and the tubular portion 3a is completely inserted into the conversion adapter 60a. Is screwed into the conversion adapter 60a.

In this state, by tightening the outer connector 1b to the conversion adapter 60a, the wall portion 25 of the hand hole 23 can be sandwiched between the flange portion 5a of the inner connector 1a and the flange portion 5b of the outer connector 1b. .. At this time, the water-expandable non-woven fabric 17a on the inner surface of the flange portion 5a of the inner connector 1a comes into contact with the inner wall surface of the hand hole 23, and the water-expandability of the outer surface of the flange portion 5b of the outer connector 1b is brought into contact with the outer wall surface of the hand hole 23. The non-woven fabric 17b comes into contact with the non-woven fabric 17b.

Here, as described above, the conduit of the double-walled square conduit using the conversion adapter 60a is backfilled with earth and sand and used. At this time, water may infiltrate through the gap between the conversion adapter 60a and the inner connector 1a or the outer connector 1b. In order to prevent this, the water-expandable non-woven fabrics 17a and 17b are arranged in the gap between the spiral portion 63 of the conversion adapter 60a and the inner connector 1a and the outer connector 1b.

(Water stop mechanism by water-expandable non-woven fabric between conversion adapter and connector)
11 (a) and 11 (b) are conceptual views showing the swelling of the water-expandable non-woven fabric 17a in the spiral mountain portion 7a, and FIG. 11 (a) is a cross-sectional view parallel to the pipe axis direction. 11 (b) is a cross-sectional view of the partition wall 9a perpendicular to the pipe axis direction. Although FIGS. 11 (a) and 11 (b) show the spiral ridge 7a in the inner connector 1a, the spiral ridge 7b in the outer connector 1b also exhibits the same behavior. Therefore, the spiral crest 7a in the inner connector 1a will be described below, and the description of the spiral crest 7b in the outer connector 1b will be omitted.

As shown in FIG. 11A, when water enters between the spiral portion 63 of the conversion adapter 60a and the spiral peak portion 7a, the water-expandable non-woven fabric 17a swells (arrow G in the figure). At this time, in the portion other than the groove 13a, the water-expandable non-woven fabric 17a is gelled by swelling between the inner surface of the spiral portion 63 of the conversion adapter 60a and the outer surface of the tubular portion 3a of the inner connector 1a. Water stoppage is ensured.

On the other hand, the swelling of the water-expandable non-woven fabric 17a increases the pressure between the spiral portion 63 and the spiral crest portion 7a of the conversion adapter 60a. However, the groove 13a functions as an escape portion of the water-expandable non-woven fabric 17a that is excessively swollen. Therefore, it is possible to suppress an excessive increase in the pressure between the spiral portion 63 and the spiral peak portion 7a, and it is possible to suppress damage to the conversion adapter 60a and the inner connector 1a.

On the other hand, as shown in FIG. 11B, partition walls 9a are formed in the grooves 13a at predetermined intervals. At the portion directly above the partition wall 9a, the water-expandable non-woven fabric 17a abuts on the upper surface of the partition wall 9a and cannot escape to the groove 13a, but as shown in the figure, the partition wall 9a is thin and the water-expandable non-woven fabric is Since it has an appropriate deformability, the water-expandable non-woven fabric 17a can escape to the space before and after the partition wall 9a. At this time, since the upper portion of the partition wall 9a is closed by the water-expandable non-woven fabric 17a, the water entering through the groove 13a can be stopped at the position of the partition wall 9a. At this time, the water-expandable non-woven fabric 17a that has absorbed water and gelled is in a substance form intermediate between a solid and a liquid, and has an appropriate viscosity and deformability, so that it is easily moved and deformed. Therefore, the water-expandable non-woven fabric 17a that has absorbed water and gelled can easily move into the space formed by the grooves 13a before and after the partition wall 9a as a result of being deformed. Further, the water-expandable non-woven fabric 17a that has absorbed water and gelled shrinks when it dries and returns to the state before swelling. Further, since some of the fibers constituting the water-expandable non-woven fabric 17a are bonded to each other by the binder resin, it easily returns to the original state when dried.

Here, the mountain portion 11a is pressed toward the groove 13a by the swelling of the water-expandable non-woven fabric 17a arranged on the outer peripheral side of the mountain portion 11a. Therefore, the force is applied in the direction in which the mountain portion 11a falls. However, since the partition walls 9a are arranged at predetermined intervals, the rigidity of the mountain portion 11a is increased by the partition wall 9a, and the collapse of the mountain portion 11a can be suppressed. Further, the water-expandable non-woven fabric 17a that has been excessively swollen and gelled is deformed and moved and arranged in the groove 13a between the mountain portions 11a, and the water-expandable non-woven fabric 17a that has moved to the groove 13a is located on the outer peripheral side of the mountain portion 11a. By deforming under the stress of the water-expandable nonwoven fabric 17a arranged, the stress due to the swelling of the water-expandable nonwoven fabric 17a arranged on the outer peripheral side of the mountain portion 11a can be relaxed.

In particular, as shown in FIG. 2A, in the cross section of the two mountain portions 11a, the angle θo of the outer ridge line of each mountain portion 11a with respect to the pipe axis direction is smaller than the angle θi of the inner ridge line. Further, the length Y of the outer support portion of the base portion of the mountain portion 11a passing through the apex of each mountain portion 11a and being divided by the line O perpendicular to the pipe axis direction is the length of the inner support portion. Longer than Z. Therefore, the mountain portion 11a is easily deformed inward by the force from the outer circumference of the mountain portion 11a. However, this deformation can be suppressed by the partition wall 9a. Further, since the tip of the inner ridge line is formed in a curved shape, the water-expandable non-woven fabric 17a that has swollen and gelled easily enters between the mountain portions 11a.

(Construction process of double wall square conduit)
12 (a) and 12 (b) are views showing a process of constructing a conduit for a double-walled square electric conduit. First, as shown in FIG. 12A, the conversion adapter 60a is attached to the hand hole 23 using the inner connector 1a and the outer connector 1b. At this time, since the spiral portion 63 of the conversion adapter 60a has the same structure as the spiral conduit 121, the conversion adapter 60a can be connected to the hand hole 23 in the same procedure as the spiral conduit 121. Therefore, it is possible to obtain a connection structure 20a in which the conversion adapter 60a and the hand hole 23 are connected.

From this state, as shown in FIG. 12A, the male joint portion 41 of the double wall square conduit 40 is inserted into the female joint portion 61a of the conversion adapter 60a (arrow J in the drawing). As described above, the male joint portion 41 and the female joint portion 61a can be connected to each other. Therefore, as shown in FIG. 12B, the double-walled square wire conduit 40 is connected to the joint portion of the conversion adapter 60a, and the double-walled square wire conduit 40 is hand-holeed via the conversion adapter 60a. A conduit 30b of a double-walled square conduit connected to 23 can be obtained. That is, according to the connection structure 20a, the spiral portion 63 attached to the hand hole 23 using the inner connector 1a and the outer connector 1b is converted into a joint portion with the double-walled square electric conduit 40. The heavy wall square type conduit 40 can be connected.

Further, FIG. 9B is a diagram showing a conversion adapter 60b. The conversion adapter 60b has a spiral portion 63 formed on one side and a male joint portion 61b which is a joint portion between the double-walled square wire tube 40 formed on the other side. It differs from FIG. 9A in that the joint portion is changed from the female joint portion 61a to the male joint portion 61b.

Similar to the conversion adapter 60a, the inner connector 1a and the outer connector 1b can be screwed into the spiral portion 63 of the conversion adapter 60b. Further, the male joint portion 61b has the same form as the male joint portion 41 of the double-walled square electric conduit 40 described above. Therefore, the male joint portion 61b of the conversion adapter 60b is composed of a retaining ring 47 mounted at a predetermined position and a rubber packing 45. The female joint portion 43 of the double-walled square electric conduit 40 can be connected to the male joint portion 61b. That is, the conversion adapter 60b can also be converted from the spiral portion 63 into which the inner connector 1a and the outer connector 1b can be arranged to the male joint portion 61b which is a joint portion between the double wall square electric conduit 40. ..

13 (a) and 13 (b) are views showing a process of constructing a conduit of a double-walled square electric conduit using a conversion adapter 60b. First, as shown in FIG. 13A, the conversion adapter 60b is attached to the hand hole 23 using the inner connector 1a and the outer connector 1b in the same procedure as described above. From the above, it is possible to obtain a connection structure 20b in which the conversion adapter 60b and the hand hole 23 are connected.

From this state, as shown in FIG. 13A, the male joint portion 61b of the conversion adapter 60b is inserted into the female joint portion 43 of the double wall square conduit 40 (arrow K in the figure). As described above, the female joint portion 43 and the male joint portion 61b can be connected to each other. Therefore, as shown in FIG. 13B, the double-walled square conduit 40 obtains the conduit 30c of the double-walled square conduit connected to the hand hole 23 via the conversion adapter 60b. Can be done. In this way, by using the connection structures 20a and 20b between the conversion adapters 60a and 60b and the hand hole 23 at least in part, the conversion adapters 60a and 60b are fitted into the joint portion of the conversion adapters 60a and 60b to form a double wall square type. It is possible to obtain conduits 30b and 30c of a double-walled square conduit to which a conduit 40 is connected. As described above, the conversion adapter may have the spiral portion 63 on one side and either the male joint portion 41 or the female joint portion 43 on the other side.

The connection structure between the conversion adapters 60a and 60b and the hand hole 23 is not limited to the above-mentioned example. For example, another spiral conduit or other conduit such as a steel pipe or a PVC pipe is connected to the end of the conversion adapters 60a and 60b on the opposite side of the connection with the hand hole 23 by a pipe joint. It can also be a structure.

(How to adjust the length of the double wall square conduit)
Next, a method of adjusting the length of the conduit of the double-walled square electric conduit 40 will be described. Depending on the length of the conduit of the double-walled square conduit 40, the double-walled square conduits 40 may be connected to each other. However, the length of the conduit of the double-walled square conduit 40 may not always be an integral multiple of the length of the double-walled square conduit 40. In this case, it is necessary to adjust the length of the conduit of the double-walled square electric conduit 40.

FIG. 14 is a diagram showing a method of adjusting the length of the conduit of the double-walled square conduit 40 using at least a part of the conduit of the double-walled square conduit 40. An example using the conversion adapter 60a will be described, but the same applies to the conversion adapter 60b. In the conversion adapter 60a shown in the upper left of FIG. 14, the length of the spiral portion 63 is set to be longer by the extra length portion 65 with respect to the minimum length required for attachment to the hand hole 23. That is, the conversion adapter 60a has an extra length for adjusting the length of the conversion adapter 60a.

When the length of the double wall square conduit 40 is short, as shown in the upper right of FIG. 14 (arrow L in the figure), the spiral portion 63 is connected from the outer connector 1b by using the conversion adapter 60a as it is. The double-walled rectangular conduit 40 is connected to the female joint portion 61a, which is arranged so as to project and protrudes greatly from the hand hole 23.

On the other hand, when the length of the double-walled square wire conduit 40 is long, as shown in the lower left of FIG. 14 (arrow M in the figure), the extra length portion 65 of the spiral portion 63 is cut. After that, as shown in the lower right of FIG. 14 (arrow N in the figure), the conversion adapter 60a after cutting is placed on the outer surface of the wall portion 25 of the hand hole 23 so that most of the spiral portion 63 is hidden by the outer connector 1b. Be connected. In this way, the fine adjustment of the conduit length of the double-walled square electric conduit can be performed by cutting the extra length portion 65 of the conversion adapter 60a.

The length of the spiral portion 63 of the conversion adapter 60a is at least the thickness of the wall portion 25 of the hand hole 23 and the length of the tubular portion 3b of the outer connector 1b (and the length of the tubular portion 3b of the outer connector 1b). The total of the tightening allowance) is required. Here, the tightening allowance is usually sufficient for 1/4 of the spiral ridge. Further, since the inner connector 1a is only screwed into the end of the conversion adapter 60a, no tightening allowance is required. Therefore, the minimum length required for the conversion adapter is the length of the portion that exceeds the total length of the wall thickness of the hand hole 23, the length of the outer connector 1b in the tube axis direction, and the tightening allowance of the outer connector 1b. Can be considered. On the other hand, the length of the spiral portion 63 of the conversion adapter 60a is, in addition to the minimum required length of the spiral portion 63, the remainder of the length adjustment at the time of connection with the double-walled square wire tube 40 described above. The length is the sum of the long portion 65.

As described above, according to the present embodiment, the cross-sectional shapes of the spiral ridges 7a and 7b of the inner connector 1a and the outer connector 1b in the direction parallel to the pipe axis direction are separated from each other by a predetermined distance. It is composed of two opposing mountain portions 11a and 11b, and grooves 13a and 13b are formed between the two opposing mountain portions 11a and 11b. Therefore, when the water-expandable nonwoven fabrics 17a and 17b arranged so as to cover the spiral ridges 7a and 7b swell, the swelled and gelled water-expandable nonwoven fabric can be released to the grooves 13a and 13b. can. Therefore, excessive stress between the conversion adapters 60a and 60b and each connector can be relieved, and damage to the member can be suppressed.

Here, the water-expandable non-woven fabric absorbs water and swells to gel, but the definition of gel in polymer chemistry is defined as a polymer having a three-dimensional network structure insoluble in a solvent and its swelling body, and is three-dimensional. A crosslinked polymer having a network structure swells due to interaction with a solvent, but exhibits a finite swelling property because it has a crosslinked structure. The degree of swelling (degree of swelling) depends on the degree of swelling, and the higher the crosslink density, the smaller the degree of swelling. In addition, the swollen gel is a substance form between liquid and solid, and by controlling its chemical composition and various factors, it has viscosity and appropriate deformability from a viscous liquid to a state close to solid. By swelling and gelling the water-expandable non-woven fabric, it is possible to ensure water stoppage and release excessive stress at the same time. Here, gelation is brought about by the crosslinked structure, but the formation of the crosslinked structure does not necessarily have to be due to the crosslinked structure, but can also be achieved by a secondary bond force between specific units of different molecular chains, for example, a hydrogen bond. Is. In addition, the crosslinked polymer having a three-dimensional network structure that has swollen and gelled can return to its original state when it shrinks due to drying.

Further, partition walls 9a and 9b are formed at predetermined intervals by connecting the mountain portions 11a and 11b so as to close the grooves 13a and 13b and substantially parallel to the pipe axis direction. Therefore, it is possible to prevent the grooves 13a and 13b from becoming an intrusion route. Further, by providing the partition walls 9a and 9b connecting the two ridges 11a and 11b, the rigidity of the two ridges 11a and 11b can be increased so that the ridges 11a and 11b fall in the grooves 13a and 13b. Deformation can be suppressed.

In particular, by providing the partition walls 9a and 9b at intervals of 30 ° to 90 ° in the circumferential direction, the water blocking effect and the rigidity improving effect can be obtained more reliably. Here, the reason why the partition walls 9a and 9b are arranged at 30 ° to 90 ° is that if it is larger than 90 °, it is difficult to obtain the effect of improving the rigidity evenly in the circumferential direction. This is because the effect of improving the rigidity becomes excessive if the arrangement interval is smaller than this. In this way, by using the inner connector 1a and the outer connector 1b, even in the case of the large-diameter conversion adapters 60a and 60b, the connection structures 20a and 20b capable of ensuring water stoppage and suppressing damage can be suppressed. Can be obtained. Further, it is possible to obtain the conduits 30b and 30c of the double-walled square electric conduit using the connection structures 20a and 20b, which can obtain the same effect.

In the present embodiment, an example in which both the inner connector 1a and the outer connector 1b are used is shown, but at least one of these may be used. That is, the inner connector 1a or the outer connector 1b may be used as one connector, and the conventional inner connector 101a or outer connector 101b may be used as the other connector, and these may be used in combination. For example, even if the inner connector 1a and the outer connector 101b are used in combination, the final path of water intrusion into the hand hole 23 or the conversion adapters 60a and 60b is surely stopped, and the inner connector 1a and this are stopped. It is possible to prevent damage to the conversion adapters 60a and 60b to be screwed. As described above, by using at least one of the inner connector 1a and the outer connector 1b, the effect of the present embodiment can be obtained at the connection portion between the inner connector 1a or the outer connector 1b and the conversion adapters 60a and 60b.

Further, by connecting the conversion adapters 60a and 60b to the hand hole 23, the double wall square conduit 40 can be connected to the hand hole 23.

At this time, by forming the extra length portion 65 in advance in the spiral portion 63 of the conversion adapters 60a and 60b, it is possible to easily finely adjust the conduit length of the double-walled square electric conduit.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention does not depend on the above-described embodiments. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical ideas described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

For example, a square type conduit in which an inner pipe does not exist is connected to the joint portion of the conversion adapter instead of the double-walled square electric conduit to the conduit of the double-walled square conduit described above. It may be a conduit of an electric conduit. Even in this case, the partition wall parallel to the pipe axis direction connecting the spiral mountain portions of the inner connector and the outer connector is substantially perpendicular to the center line at the predetermined position in the direction perpendicular to the pipe axis direction. A plurality of them are formed substantially parallel to each other at predetermined intervals in the direction at predetermined intervals above and below the center line position and the center line. Further, even in this case, a plurality of partition walls formed substantially parallel to each other at predetermined intervals have a center line position and a vertical radius of 1/2 to 1/5 of the center line in the direction perpendicular to the pipe axis direction. It is desirable that they are formed at predetermined intervals between them.

1a, 1aa ……… Inner connector 1b ……… Outer connector 3a, 3b ……… Cylindrical part 5a, 5b ……… Flange part 7a, 7b ……… Spiral mountain part 9a, 9b ……… Partition wall 11a , 11b ……… Yamabe 13a, 13b ……… Grooves 15a, 15b ……… Rubber packing 17a, 17b ……… Water-expandable non-woven fabric 20, 20a, 20b ……… Connection structure 23 ……… Hand hole (minutes) Kiseki)
24 ………… Through hole 25 ………… Walls 30b, 30c ………… Double wall square wire tube line 40 ………… Double wall square wire tube 41 ………… Male joint 43 …… … Female joint 45 ………… Rubber packing 46 ………… Claw 47 ………… Retaining ring 48 ………… Slide guide 49 ………… Small diameter 50 ………… Regulator 51 ………… Large diameter 52 ……… Slope 53 ………… Ring fitting 54 ………… Cylindrical part 57 ………… Outer pipe 59 ………… Inner pipe 60a, 60b ………… Conversion adapter 61a ………… Male joint 61b… …… Female joint 63 ………… Spiral portion 65 ………… Extra length 101a ………… Inner connector 101b ………… Outer connectors 107a, 107b ………… Spiral ridges 117a, 117b ………… Water expansion Sexual non-woven fabric 121 ………… Spiral wire tube 123 ………… Hand hole 124 ………… Through hole 125 ………… Wall

Claims (13)

It is a conduit of a double-walled square electric conduit composed of an outer pipe and a straight tubular inner pipe arranged inside the outer pipe.
The double wall square conduit is connected to the hand hole via a conversion adapter, and is connected to the hand hole.
The conversion adapter can convert a spiral portion attached to the hand hole to a joint portion of a square conduit using an inner connector and an outer connector.
The conversion adapter is composed of a joint portion between the spiral portion formed on one side and a square conduit formed on the other side.
Both the inner connector and the outer connector have a substantially T-shaped cross section, and a cylindrical portion having a spiral mountain portion and one end of the tubular portion are substantially perpendicular to the pipe end portion of the tubular portion. Has a flange that expands in diameter
A water-expandable non-woven fabric is provided on the outer peripheral surface of the tubular portion of the inner connector, and a rubber packing and a water-expandable non-woven fabric are attached to the inner surface of the flange portion of the inner connector in this order.
A water-expandable non-woven fabric is provided on the inner peripheral surface of the tubular portion of the outer connector, and a rubber packing and a water-expandable non-woven fabric are attached to the outer surface of the flange portion of the outer connector in this order.
The inner connector is screwed into the inner peripheral surface of the end portion of the spiral portion, and the water-expandable non-woven fabric on the inner surface of the flange portion of the inner connector abuts on the inner wall surface of the hand hole.
The outer connector is screwed onto the outer peripheral surface of the spiral portion, and the water-expandable non-woven fabric on the outer surface of the flange portion of the outer connector comes into contact with the outer wall surface of the hand hole.
The wall portion of the hand hole is sandwiched between the flange portion of the inner connector and the flange portion of the outer connector.
The cross-sectional shape of at least one of the inner connector or the outer connector in the direction parallel to the tube axis direction of the spiral ridge of the tubular portion is composed of two ridges facing each other at a predetermined distance from each other. In order to close the groove formed between the facing mountain portions, partition walls connecting the mountain portions and substantially parallel to the pipe axis direction are formed at predetermined intervals, and the water provided in the tubular portion. The expandable non-woven fabric is formed so as to straddle the upper portion of the groove formed between the mountain portions, and the double-walled square electric conduit is connected to the joint portion of the conversion adapter. Double-walled square conduit. The double-walled square electric conduit is formed from a male joint portion and a female joint portion formed at both ends of the outer pipe, and a main body portion connecting both the male joint portion and the female joint portion. The main body is formed by alternately and repeatedly forming a substantially cylindrical small diameter portion and a substantially rectangular large diameter portion having a larger diameter, and further, the straight tubular inner tube has a substantially cylindrical shape. The conduit of a double-walled square conduit according to claim 1, wherein the outer surface of the inner pipe is fused to each other at the inner surface of the outer pipe and the small diameter portion of the outer pipe. In the male joint portion, the inner pipe is either housed and covered inside the male joint portion or integrated with the inner surface in the vicinity of the tip portion of the male joint portion. The conduit of a double-walled square electric conduit according to claim 2, wherein the female joint portion is cut so as not to obstruct the connection with the male joint portion. The cross-sectional shape of the inner connector and the tubular portion of the outer connector in a direction parallel to the tube axis direction of the spiral mountain portion is composed of two mountain portions facing each other at a predetermined distance from each other. , The partition walls connecting the mountain portions and substantially parallel to the pipe axis direction are formed at predetermined intervals so as to close the grooves formed between the mountain portions facing each other, and are provided in the tubular portion. The double-walled square type according to any one of claims 1 to 3, wherein the water-expandable non-woven fabric is formed so as to straddle and cover the upper portion of the groove formed between the mountain portions. Conduit of electrical conduit. The partition wall parallel to the pipe axis direction connecting the spiral ridges of the inner connector and the spiral ridges of the outer connector is provided at predetermined intervals of 30 ° to 90 ° in the circumferential direction of the spiral ridges. The conduit of the double-walled square electric conduit according to any one of claims 1 to 4, characterized in that. The partition wall parallel to the pipe axis direction connecting the spiral mountain portions of the inner connector and the outer connector with respect to the center line at a predetermined position is substantially perpendicular to the pipe axis direction. The pipeline of a double-walled square electric wire tube according to any one of claims 1 to 4, wherein a plurality of tubes are formed substantially parallel to each other in a vertical direction at predetermined intervals. A plurality of the partition walls formed substantially in parallel at the predetermined intervals are formed at predetermined intervals between 1/2 to 1/5 of the radius vertically across the center line position and the center line in the direction perpendicular to the pipe axis direction. The conduit of the double-walled square conduit according to claim 6, wherein the conduit is formed of. The joint portion of the conversion adapter is composed of a female joint portion of a square conduit.
The female joint portion is claimed from claim 1, wherein a male joint portion composed of a substantially C-shaped or annular retaining ring mounted at a predetermined position and an annular rubber packing is fitted. Item 7. The conduit of the double-walled square electric conduit according to any one of Item 7. The joint portion of the conversion adapter is composed of a male joint portion of a square conduit.
Claims 1 to 7 are characterized in that the male joint portion is composed of a substantially C-shaped or annular retaining ring mounted at a predetermined position of the male joint portion and an annular rubber packing. The conduit of the double-walled square conduit described in any of. The method according to any one of claims 1 to 9, wherein the conversion adapter has an extra length in the spiral portion of the conversion adapter for adjusting the length of the conversion adapter. Double-walled square conduit. In the conduit of the double-walled square conduit according to claim 1, the partition wall parallel to the pipe axis direction connecting the spiral ridges of the inner connector and the outer connector is a pipe. A plurality of conversion adapters are formed in a direction perpendicular to the axial direction, substantially parallel to the center line of a predetermined position at a predetermined interval in a direction substantially perpendicular to the center line, and vertically at a predetermined interval with the center line position and the center line in between. A conduit of a square conduit, characterized in that a square conduit having no inner pipe is connected to the joint portion of the above in place of the double-walled square conduit. A plurality of the partition walls formed substantially in parallel at the predetermined intervals are formed at predetermined intervals between 1/2 to 1/5 of the radius vertically across the center line position and the center line in the direction perpendicular to the pipe axis direction. The conduit of the square conduit according to claim 11, wherein the conduit is formed of. A method for adjusting the length of a double-walled square conduit using at least a part of the conduit of the double-walled square conduit according to claim 10, wherein the conduit length is finely adjusted. , A method for adjusting the length of a conduit of a double-walled square electric conduit, which is performed by cutting the conversion adapter.

Images