JP7548558B2 - Connection pipe and connection structure - Google Patents

Description

The present invention relates to a connecting pipe and a connecting structure.

Reinforced concrete pipes are known as piping that is buried underground. Examples of reinforced concrete pipes include Hume pipes (e.g., Patent Document 1) and pedestal pipes (e.g., Patent Document 2). The strength and pipe shapes of Hume pipes and pedestal pipes are standardized by Japanese Industrial Standards (e.g., JIS A 5372) and Japan Sewage Works Association Standards (JSWAS A-1, JSWAS A-9), etc.

Utility Model Registration No. 3137731 Utility Model Registration No. 3054788

Pedestal pipes have a flat pipe thickness section on the bottom side, and have the advantage of being stronger than Hume pipes, which have a cylindrical cross-sectional shape. On the other hand, pedestal pipes have the disadvantage of being more expensive to manufacture, as they require more concrete than Hume pipes. For this reason, it is necessary to use different concrete pipes depending on the construction conditions, such as using Hume pipes normally and using pedestal pipes in places where greater strength is required.

Each pedestal pipe has a socket portion (receiving port) formed at one end in the pipe axis direction, and a spigot portion (spout) formed at the other end. By inserting the spigot portion of one pedestal pipe into the socket portion of another pedestal pipe, multiple pedestal pipes can be connected in series in the pipe axis direction. Similarly, Hume pipes also have socket portions and spigot portions formed, and multiple Hume pipes can be connected in series in the pipe axis direction.

The shapes of the socket and spigot parts of the Hume pipe are different from those of the pedestal pipe, so the Hume pipe cannot be directly connected to the pedestal pipe. In addition, the shapes of the Hume pipe and the pedestal pipe are each standardized, so the shapes of the socket and spigot parts of each cannot be changed.

For this reason, in the past, when connecting concrete pipes with different shaped socket and spigot sections, such as a Hume pipe and a pedestal pipe, the connection was made via a manhole (connecting manhole), or by bringing the socket and spigot sections of the concrete pipes close together and wrapping them in cast-in-place concrete to forcibly connect them.

However, when connecting through a manhole, there is the issue of the extra cost of constructing the manhole. Also, when connecting by wrapping it in cast-in-place concrete, there are issues such as the extra cost of constructing the cast-in-place concrete and reduced strength and precision of the connection.

In addition, compared to concrete pipes (circular pipes) with a cylindrical cross-section such as Hume pipes, pedestal pipes have the problem that they are difficult to connect to a manhole (e.g., a manhole). When connecting a circular pipe to a manhole, it is easy to connect by forming a circular through-hole in the manhole and inserting the circular pipe into the through-hole. In contrast, since pedestal pipes have a thick pipe portion at the bottom, it is necessary to form an extra-large circular through-hole in the manhole, insert the pedestal pipe, and fill the gap with cast-in-place concrete or the like. For this reason, in order to connect a pedestal pipe to a manhole, it is necessary to prepare a manhole of a size that can form the above-mentioned through-hole, and it is also necessary to spend manpower to fill the gap between the pedestal pipe and the manhole, which increases construction costs.

The present invention aims to provide a connecting pipe and structure that can be used more generally to connect different types of concrete pipes together or to connect a concrete pipe to a manhole.

(1) The connecting pipe of the present invention is a connecting pipe that is connected to any two of a first concrete pipe, a second concrete pipe of a different standard from the first concrete pipe, and a manhole, and is provided with a connecting pipe socket portion formed at one end in the pipe axial direction and connected to a first spigot portion of the first concrete pipe or a second spigot portion of the second concrete pipe having an outer diameter smaller than that of the first spigot portion, and the connecting pipe socket portion includes a large diameter portion located at the end side in the pipe axial direction, and a small diameter portion located inside the large diameter portion in the pipe axial direction and having an inner diameter smaller than that of the large diameter portion, the large diameter portion having an inner diameter that can be fitted with the first spigot portion, and the small diameter portion having an inner diameter that can be fitted with the second spigot portion.

The connecting pipe socket of the present invention has two internal diameters, a large diameter section and a small diameter section, so it can be connected to both the first spigot section of the first concrete pipe and the second spigot section of the second concrete pipe. This allows the connecting pipe to be used more versatilely than a connecting pipe that has a socket section that can only connect to one type of concrete pipe.

(2) Preferably, the device further includes a first gasket arranged along the circumferential direction of the large diameter portion, and a second gasket is arranged along the circumferential direction of the outer circumferential surface of the second spigot portion, the large diameter portion has an inner diameter that can fit with the first spigot portion via the first gasket, and the small diameter portion has an inner diameter that can fit with the second spigot portion via the second gasket.

By configuring it in this way, whether the first spigot portion is inserted into the connecting pipe or the second spigot portion is inserted into the connecting pipe, the first gasket or the second gasket can be used to connect the pipe while keeping it waterproof.

(3) The first gasket has a tip portion that can slide against at least one of the outer circumferential surface of the second spigot portion that is fitted into the small diameter portion and the second gasket. The tip portion slides against the outer circumferential surface of the second spigot portion or the second gasket, thereby guiding the second concrete pipe to the radial center. This makes it possible to more accurately insert the second spigot portion into the connecting pipe socket portion while suppressing radial deviation of the second spigot portion.

(4) Preferably, the small diameter portion has an inner diameter that can fit with the second spigot portion by contacting the outer peripheral surface of the second spigot portion or an adhesive applied to the outer peripheral surface. By configuring in this way, components such as the second gasket described above are not required, and the number of parts required for installation can be reduced.

(5) Preferably, the first concrete pipe is a base pipe, and the second concrete pipe is a Hume pipe. In such a case, it is not easy to directly connect the first concrete pipe and the second concrete pipe, so there is a high need to connect them via a connecting pipe.

(6) Preferably, the cross-sectional shape perpendicular to the tube axis direction is cylindrical. By configuring it in this way, when connecting the connecting pipe and the manhole, the area of the through hole drilled in the manhole can be reduced.

(7) Preferably, the strength is closer to the strength of the first concrete pipe than to the strength of the second concrete pipe. By configuring it in this way, the connecting pipe can be installed at the same depth as the first concrete pipe without reinforcing it.

(8) Preferably, the pipe further includes a cylindrical portion that is provided circumferentially around the small diameter portion and fills in the step between the inner circumferential surface of the first spigot portion that is fitted into the large diameter portion and the small diameter portion. The cylindrical portion fills in the step between the inner circumferential surface of the first spigot portion and the small diameter portion, thereby smoothing the flow of fluid (e.g., water) through the first concrete pipe and the connecting pipe.

(9) Preferably, the cylindrical portion includes a sponge material that is crushed by the second spigot portion that is fitted into the small diameter portion. This configuration has the function of filling in the step that occurs between the small diameter portion and the first spigot portion when inserting the first spigot portion, and the work can be performed while the cylindrical portion is fitted into the small diameter portion when inserting the second spigot portion. This reduces the labor required to remove the cylindrical portion.

(10) The cylindrical portion further contains a resin material that is impregnated into the sponge material in a fluid state and that can harden after the sponge material is crushed. This configuration makes it possible to more firmly connect the second concrete pipe and the connecting pipe while sealing the gap between them.

(11) Further comprising a connecting pipe spigot portion formed at the other end in the pipe axial direction and connected to a first socket portion of the first concrete pipe or a second socket portion of the second concrete pipe having an inner diameter smaller than that of the first socket, the connecting pipe spigot portion having an outer diameter capable of engaging with the first socket portion or the second socket portion.

(12) The connecting pipe spigot portion has an outer diameter that can fit with the second socket portion, and further includes a conversion portion that can be attached to the outer peripheral surface of the connecting pipe spigot portion, and the conversion portion has an inner diameter that can fit with the connecting pipe spigot portion and an outer diameter that can fit with the first socket portion.

(13) The connection structure of the present disclosure is a connection structure comprising the connection pipe of (11) or (12) above, the first concrete pipe connected to one of the connection pipe socket portion and the connection pipe spigot portion, and the second concrete pipe connected to the other of the connection pipe socket portion and the connection pipe spigot portion.

(14) The connection structure of the present disclosure is a connection structure comprising a connecting pipe as described above in (1) to (10), the first concrete pipe connected to the connecting pipe socket portion or the second concrete pipe connected to the connecting pipe socket portion, and the manhole connected to the other end of the connecting pipe in the pipe axis direction.

The present invention provides a connecting pipe and connection structure that can be used more generally to connect different types of concrete pipes together, or to connect a concrete pipe to a manhole.

1 is a cross-sectional view of a connection structure according to a first embodiment. FIG. 2 is an enlarged cross-sectional view of a socket portion of the connecting pipe of FIG. 1 . 2 is an explanatory diagram showing how the socket portion of the connecting pipe in FIG. 1 is connected to a first concrete pipe. FIG. 1 is an explanatory diagram showing how the socket portion of the connecting pipe in FIG. 1 is connected to a second concrete pipe. 2 is an explanatory diagram showing how the spigot portion of the connecting pipe in FIG. 1 is connected to a first concrete pipe. 2 is an explanatory diagram showing how the spigot portion of the connecting pipe in FIG. 1 is connected to a second concrete pipe. An explanatory diagram showing how the spigot portion of the connecting pipe in the second embodiment connects to a second concrete pipe. An explanatory diagram showing how the spigot portion of the connecting pipe in the second embodiment connects to the first concrete pipe. 13 is an explanatory diagram showing a state in which a spigot portion of a connecting pipe according to a third embodiment is connected to a manhole. FIG. 13A to 13C are explanatory diagrams showing a connection structure according to a fourth embodiment and a manufacturing method of the connection structure. An explanatory diagram showing how the socket portion of the connecting pipe in the modified example is connected to a second concrete pipe. An explanatory diagram showing how the socket portion of the connecting pipe in the modified example is connected to a second concrete pipe.

The following describes an embodiment of the present invention with reference to the drawings.

First Embodiment
[Overall configuration of connection structure]
1 is a cross-sectional view showing a schematic configuration of a connection structure 1 according to the present embodiment. The connection structure 1 includes a first concrete pipe 20, a second concrete pipe 30 having a different standard from that of the first concrete pipe 20, and a connection pipe 10 connected to the first concrete pipe 20 and the second concrete pipe 30.

The connecting pipe 10 is a concrete pipe that is long in the pipe axis direction. FIG. 1 shows a cross section in the pipe axis direction. The connecting pipe 10 comprises a pipe body 11, a spigot portion 12 (the "connecting pipe spigot portion" in this disclosure), and a socket portion 13 (the "connecting pipe socket portion" in this disclosure). The socket portion 13 is a receiving port formed at one end of the pipe body 11 in the pipe axis direction. The spigot portion 12 is a spigot portion formed at the other end of the pipe body 11 in the pipe axis direction. Hereinafter, the socket portion 13 side in the pipe axis direction will be appropriately referred to as "one side in the pipe axis direction", and the spigot portion 12 side will be appropriately referred to as "the other side in the pipe axis direction".

The first concrete pipe 20 is a pipe made of concrete and includes a pipe body 21, a spigot portion 22 (the "first spigot portion" in this disclosure), and a socket portion 23 (the "first socket portion" in this disclosure). The socket portion 23 is a receiving port formed at one end of the pipe body 21 in the pipe axis direction. The spigot portion 22 is a spigot portion formed at the other end of the pipe body 21 in the pipe axis direction.

The first concrete pipe 20 is, for example, a base-mounted pipe. Examples of base-mounted pipes include BZ base-mounted pipes and VP base-mounted pipes, but in this embodiment, the BZ base-mounted pipe "BZ-600" will be used as an example. The first concrete pipe 20 has a pipe thickness section 24 at the bottom in an area on one side of the pipe axis direction from the spigot section 22. Therefore, the outer peripheral surfaces 21b, 23b of the pipe body 21 and the socket section 23 have a cross-sectional shape that is circular on the top side and trapezoidal on the bottom side. The outer peripheral surface 22b of the spigot section 22 has a cross-sectional shape that is a perfect circle.

The inner circumferential surfaces 21a, 22a, 23a of the pipe body 21, spigot portion 22, and socket portion 23 each have a perfectly circular cross-sectional shape. The inner diameter D21 of the pipe body 21 and the inner diameter of the spigot portion 22 are equal, and the inner circumferential surfaces 21a and 22a are continuous without any steps. The inner diameter D23 of the socket portion 23 is larger than the inner diameter D21 of the pipe body 21, and there is a step between the inner circumferential surface 23a and the inner circumferential surface 21a.

The first concrete pipe 20 further includes a gasket 25. The gasket 25 is a resin or rubber sealing member provided along the circumferential direction of the inner circumferential surface 23a. The gasket 25 has the function of improving water-stopping properties by deforming when connecting the socket portion 13 of the connecting pipe 10 or the spigot portion 22 of another first concrete pipe 20 to the socket portion 23 of the first concrete pipe 20.

The shape and dimensions of the first concrete pipe 20 are regulated by standards such as the Japan Industrial Standards and the Japan Sewage Works Association Standards (for example, the Japan Sewage Works Association Standard JSWAS A-9). For example, if the first concrete pipe 20 is a BZ base pipe "BZ-600", the inner diameter D21 (nominal diameter D21) of the pipe body 21 is regulated to 600 mm, the outer diameter D22 of the spigot portion 22 is regulated to 713 mm, the inner diameter D23 of the socket portion 23 is regulated to 727 mm, and the inner diameter D24 of the gasket 25 is regulated to 703 mm.

The shape and dimensions stipulated by this standard allow the spigot portion 22 of the first concrete pipe 20 to fit into the socket portion 23 of another first concrete pipe 20. This allows multiple first concrete pipes 20 to be connected in series in the pipe axial direction.

The strength of the first concrete pipe 20 is regulated by regulations. Here, the strength is the upper limit (standard value) of the load that can maintain a reasonable cross-sectional shape. The load includes, for example, the cracking load and the breaking load. If the first concrete pipe 20 is a BZ base pipe "BZ-600", the standard value of the cracking load is 73.6 kN/m, and the standard value of the breaking load is 95.7 kN/m.

The second concrete pipe 30 is a pipe made of concrete and includes a pipe body 31, a spigot portion 32 (the "second spigot portion" in this disclosure), and a socket portion 33 (the "second socket portion" in this disclosure). The socket portion 33 is a receiving port formed at one end of the pipe body 31 in the pipe axis direction. The spigot portion 32 is a spigot portion formed at the other end of the pipe body 31 in the pipe axis direction.

The second concrete pipe 30 is, for example, a Hume pipe. Examples of Hume pipes include B-type pipes and NC-type pipes, but in this embodiment, a B-type pipe with a nominal diameter of 600 mm will be used as an example. The cross-sectional shape of the second concrete pipe 30 is cylindrical, and the inner surfaces 31a, 32a, 33a and the outer surfaces 31b, 32b, 33b of the pipe body 31, spigot portion 32, and socket portion 33 all have a perfectly circular cross-sectional shape.

The inner diameter D31 of the pipe body 31 and the inner diameter of the spigot portion 32 are equal, and the inner peripheral surface 31a and the inner peripheral surface 32a are continuous without any step. The inner diameter D33 of the socket portion 33 is larger than the inner diameter D31 of the pipe body 31, and there is a step between the inner peripheral surface 33a and the inner peripheral surface 31a.

The shape and dimensions of the second concrete pipe 30 are specified by standards such as the Japan Industrial Standards, the Japan Sewage Works Association Standards, and the National Hume Pipe Association Standards (e.g., JIS A 5372). For example, if the second concrete pipe 30 is a B-type Hume pipe with a nominal diameter of 600 mm, the inner diameter D31 (nominal diameter D31) of the pipe body 31 is specified as 600 mm, the outer diameter D32 of the spigot portion 32 is specified as 690 mm, and the inner diameter D33 of the socket portion 33 is specified as 704 mm.

The shape and dimensions stipulated by this standard allow the spigot portion 32 of the second concrete pipe 30 to fit into the socket portion 33 of another second concrete pipe 30. This allows multiple second concrete pipes 30 to be connected in series in the pipe axial direction.

The strength of the second concrete pipe 30 is also regulated by regulations. If the second concrete pipe 30 is a B-type Hume pipe with a nominal diameter of 600 mm, the standard value for the cracking load is 49.1 kN/m, and the standard value for the breaking load is 77.5 kN/m. Thus, the strength (cracking load and breaking load) of the second concrete pipe 30 is lower than the strength of the first concrete pipe 20.

As described above, when the first concrete pipe 20 and the second concrete pipe 30 have the same nominal diameters D21, D31, the standards stipulate that the outer diameters D22, D32 of the spigot portions 22, 32 are different, and the inner diameters D23, D33 of the socket portions 23, 33 are different. In this embodiment, the outer diameter D22 (713 mm) is larger than the outer diameter D32 (690 mm), and the inner diameter D23 (727 mm) is larger than the inner diameter D33 (704 mm). For this reason, the first concrete pipe 20 and the second concrete pipe 30 cannot be directly connected.

The connection structure 1 of this embodiment connects two types of concrete pipes 20 and 30 that cannot be directly connected due to differences in standard shapes by placing a connecting pipe 10 between a first concrete pipe 20 and a second concrete pipe 30.

In FIG. 1, as an example of the connection structure 1, a structure in which a first concrete pipe 20 is connected to the spigot portion 12 side of the connection pipe 10, and a second concrete pipe 30 is connected to the socket portion 13 side of the connection pipe 10 is shown. However, the connection structure 1 is not limited to this, and may be a structure in which a second concrete pipe 30 is connected to the spigot portion 12 side of the connection pipe 10, and a first concrete pipe 20 is connected to the socket portion 13 side of the connection pipe 10. The manner in which the connection pipe 10 is connected to various concrete pipes 20, 30 will be described later.

[Components of the connecting pipe]
The configuration of each part of the connecting pipe 10 will be described below.
The pipe body 11 is a long pipe in the pipe axial direction and has a cylindrical cross-sectional shape. The inner peripheral surface 11a and the outer peripheral surface 11b of the pipe body 11 each have a perfectly circular cross-sectional shape. The inner diameter D11 of the pipe body 11 is equal to the nominal diameters D21, D31 of the first concrete pipe 20 and the second concrete pipe 30, and the inner diameter D11 in this embodiment is 600 mm.

The spigot portion 12 has a cylindrical cross-sectional shape, and the inner peripheral surface 12a and the outer peripheral surface 12b of the spigot portion 12 each have a perfectly circular cross-sectional shape. The inner peripheral surface 12a of the spigot portion 12 is continuous with the inner peripheral surface 11a of the tube body 11 in the tube axial direction without any step. The outer diameter D12 of the spigot portion 12 is equal to the outer diameter D22 of the spigot portion 22, and is 713 mm in this embodiment.

FIG. 2 is an enlarged cross-sectional view of the socket portion 13 of the connecting pipe 10. As shown in FIG.
The inner peripheral surface 13a of the socket portion 13 includes a large diameter portion 14 and a small diameter portion 15. The large diameter portion 14 is a region located on the end side in the tube axis direction (one end in the tube axis direction). The small diameter portion 15 is a region adjacent to the inside in the tube axis direction of the large diameter portion 14 (the other end in the tube axis direction). Both the large diameter portion 14 and the small diameter portion 15 have a perfectly circular cross-sectional shape.

The inner diameter D13 of the large diameter portion 14 is equal to the inner diameter D23 of the socket portion 23 of the first concrete pipe 20, and is 727 mm in this embodiment. The inner diameter D14 of the small diameter portion 15 is equal to the inner diameter D33 of the socket portion 33 of the second concrete pipe 30, and is 704 mm in this embodiment. Therefore, the inner diameter D14 of the small diameter portion 15 is smaller than the inner diameter D13 of the large diameter portion 14 (D14<D13) and larger than the inner diameter D11 of the pipe body 11 (D14>D11). Therefore, there is a step between the large diameter portion 14 and the small diameter portion 15, and there is also a step between the small diameter portion 15 and the inner peripheral surface 11a. The width G1 of the step between the small diameter portion 15 and the inner peripheral surface 11a is half the difference between the inner diameter D14 and the inner diameter D11, and is 52 mm in this embodiment.

The connecting pipe 10 further includes a gasket 16 and a cylindrical portion 17. In FIG. 1, the gasket 16 and the cylindrical portion 17 are omitted. The gasket 16 is provided along the circumferential direction of the large diameter portion 14. The gasket 16 is a sealing member made of resin or rubber. The gasket 16 deforms when the spigot portion 22 of the first concrete pipe 20 is connected to the socket portion 13 of the connecting pipe 10, thereby sealing the gap between the first concrete pipe 20 and the connecting pipe 10 and improving water stopping properties.

The inner diameter D15 of the gasket 16 is equal to the inner diameter D24 of the gasket 25 of the first concrete pipe 20, which is 703 mm in this embodiment. Therefore, the inner diameter D15 of the gasket 16 is slightly smaller than the inner diameter D14 of the small diameter portion 15, which is 1 mm smaller in this embodiment. Therefore, when connecting the spigot portion 32 of the second concrete pipe 30 to the socket portion 13 of the connecting pipe 10, the tip portion 16a of the gasket 16 slides against the outer circumferential surface 32b of the spigot portion 32, so that the gasket 16 has a function of guiding the second concrete pipe 30 to the radial center (centering function).

The cylindrical portion 17 has a cylindrical cross-sectional shape and is provided along the circumferential direction of the small diameter portion 15. The cylindrical portion 17 is press-fitted into the small diameter portion 15 with a predetermined tightening margin. The cylindrical portion 17 can be removed from the small diameter portion 15 by pulling it out in one axial direction of the tube. The cylindrical portion 17 may be provided so as not to be detachable from the small diameter portion 15. For example, the outer peripheral surface of the cylindrical portion 17 and the small diameter portion 15 may be bonded with an adhesive.

When attached to the small diameter portion 15, the thickness of the cylindrical portion 17 is equal to or slightly smaller than the width G1 of the step between the small diameter portion 15 and the inner circumferential surface 11a. The cylindrical portion 17 has the function of filling the step (gap) that occurs between the inner circumferential surface 22a of the spigot portion 22 and the small diameter portion 15 when the spigot portion 22 of the first concrete pipe 20 is connected to the socket portion 13 of the connecting pipe 10.

The cylindrical portion 17 includes a sponge material 17a. The sponge material 17a is a porous material, for example, a synthetic resin such as foamed polyurethane. The sponge material 17a may be a rubber sponge. The hardness and elasticity of the sponge material 17a are designed so that it is crushed in the axial direction by the spigot portion 32 of the second concrete pipe 30 when the second concrete pipe 30 described below is connected to the connecting pipe 10.

The cylindrical portion 17 may further include a resin material 17b. The resin material 17b is a resin material that is impregnated into the sponge material 17a in a fluid state, and is, for example, an epoxy resin dissolved in a solvent such as an organic solvent. The resin material 17b is supplied to the sponge material 17a at the construction site immediately before connecting the spigot portion 32 of the second concrete pipe 30 to the socket portion 13 of the connecting pipe 10. The resin material 17b can be hardened after the sponge material 17a is crushed by the spigot portion 32. Specifically, after the sponge material 17a is crushed, the solvent dries and hardens. As a result, the resin material 17b has the function of connecting the spigot portion 32 and the small diameter portion 15 and improving the water-stopping property between the spigot portion 32 and the small diameter portion 15.

The resin material 17b may be a two-component epoxy resin. In this case, the resin material 17b contains a main agent and a hardener, each of which has fluidity. The resin material 17b is supplied to the sponge material 17a in a state where the main agent and hardener are mixed at the construction site, and then the sponge material 17a is crushed by the spigot portion 32, causing the resin material 17b to harden due to heat generation such as adiabatic compression.

The strength of the connecting pipe 10 is closer to the strength of the first concrete pipe 20 than to the strength of the second concrete pipe 30. For example, the crack load of the connecting pipe 10 is higher than the average value (61.35 kN/m) of the crack load of the first concrete pipe 20 (73.6 kN/m) and the crack load of the second concrete pipe 30 (49.1 kN/m), and more specifically, is the same as the crack load of the first concrete pipe 20 (73.6 kN/m). The breaking load of the connecting pipe 10 is higher than the average value (86.6 kN/m) of the crack load of the first concrete pipe 20 (95.7 kN/m) and the breaking load of the second concrete pipe 30 (77.5 kN/m), and more specifically, is the same as the breaking load of the first concrete pipe 20 (95.7 kN/m).

By setting the strength of the connecting pipe 10 to the above value, it is possible to prevent the connecting pipe 10 from becoming weak when the connecting pipe 10 is connected to the first concrete pipe 20 and the second concrete pipe 30. As a result, the connecting pipe 10 can be connected without being reinforced.

[How to connect the connecting pipe]
Next, a method for connecting the connecting pipe 10 will be described.

Figure 3 shows how the spigot portion 22 of the first concrete pipe 20 is connected to the socket portion 13 of the connecting pipe 10. Figure 3(a) shows the state before connection, and Figure 3(b) shows the state after connection. The inner diameter D13 of the large diameter portion 14 of the connecting pipe 10 is equal to the inner diameter D23 of the socket portion 23 of the first concrete pipe 20. Therefore, the large diameter portion 14 can fit into the outer peripheral surface 22b of the spigot portion 22 of the first concrete pipe 20.

First, at the construction site where the first concrete pipe 20 and the connecting pipe 10 are to be connected, a lubricant is applied to the outer circumferential surface 22b of the spigot portion 22 of the first concrete pipe 20. Next, the spigot portion 22 is inserted into the socket portion 13. The spigot portion 22 is inserted to the other end of the large diameter portion 14 in the pipe axis direction (or to a position slightly to one side of the end in the pipe axis direction) as shown in FIG. 3(b) while deforming the gasket 16. Because the inner diameter D14 of the small diameter portion 15 is smaller than the outer diameter D22 of the spigot portion 22, the spigot portion 22 is not inserted in the other pipe axis direction beyond the step between the large diameter portion 14 and the small diameter portion 15.

The gasket 16 can seal the gap between the first concrete pipe 20 and the connecting pipe 10 by deforming and filling the gap between the outer circumferential surface 22b of the spigot portion 22 and the large diameter portion 14. The cylindrical portion 17 can smooth the flow of fluid (e.g., water) through the first concrete pipe 20 and the connecting pipe 10 by filling the step between the inner circumferential surface 22a of the spigot portion 22 and the small diameter portion 15.

Figure 4 shows how the spigot portion 32 of the second concrete pipe 30 is connected to the socket portion 13 of the connecting pipe 10. Figure 4(a) shows the state before connection, and Figure 4(b) shows the state after connection. The inner diameter D14 of the small diameter portion 15 of the connecting pipe 10 is equal to the inner diameter D33 of the socket portion 33 of the second concrete pipe 30. Therefore, the small diameter portion 15 can fit into the outer peripheral surface 32b of the spigot portion 32 of the second concrete pipe 30.

First, at the construction site where the second concrete pipe 30 and the connecting pipe 10 are to be connected, a lubricant is applied to the outer surface 32b, and the sponge material 17a is impregnated with the resin material 17b. Next, the spigot portion 32 is inserted into the socket portion 13. The outer surface 32b of the spigot portion 32 is in sliding contact with the tip portion 16a of the gasket 16, and is inserted up to the other end of the small diameter portion 15 in the pipe axis direction (or to a position slightly to one side of that end in the pipe axis direction) as shown in FIG. 4(b).

The tip 16a slides against the outer circumferential surface 32b to guide the second concrete pipe 30 toward the radial center. This allows the spigot portion 32 to be inserted more accurately into the socket portion 13 while suppressing radial deviation of the spigot portion 32.

When the spigot portion 32 is inserted, the sponge material 17a contained in the cylindrical portion 17 is crushed by the spigot portion 32. In this way, by configuring the sponge material 17a to be crushed by the spigot portion 32, it has the function of filling in the step that occurs between the inner circumferential surface 22a and the small diameter portion 15 when the spigot portion 22 is inserted, and the work can be performed while the cylindrical portion 17 is fitted into the small diameter portion 15 when the spigot portion 32 is inserted. This reduces the labor required for removing the cylindrical portion 17.

After the sponge material 17a is crushed, the resin material 17b impregnated in the sponge material 17a hardens. This allows the second concrete pipe 30 and the connecting pipe 10 to be more firmly connected while more reliably sealing the gap between them.

Figure 5 shows how the spigot portion 12 of the connecting pipe 10 is connected to the socket portion 23 of the first concrete pipe 20. Figure 5(a) shows the state before connection, and Figure 5(b) shows the state after connection. The outer diameter D12 of the spigot portion 12 of the connecting pipe 10 is equal to the outer diameter D22 of the spigot portion 22 of the first concrete pipe 20. Therefore, the spigot portion 12 can fit into the socket portion 23 (inner diameter D23) of the first concrete pipe 20.

First, at the construction site where the first concrete pipe 20 and the connecting pipe 10 are to be connected, a lubricant is applied to the outer peripheral surface 12b. Next, the spigot portion 12 is inserted into the socket portion 23. The outer peripheral surface 12b of the spigot portion 12 is inserted up to the other end of the inner peripheral surface 23a in the pipe axial direction (or to a position slightly to one side of that end in the pipe axial direction) as shown in FIG. 5(b) while deforming the gasket 25.

Figure 6 shows how the spigot portion 12 of the connecting pipe 10 is connected to the socket portion 33 of the second concrete pipe 30. Figure 6(a) shows the state before connection, and Figure 6(b) shows the state after connection. The outer diameter D12 of the spigot portion 12 of the connecting pipe 10 is larger than the inner diameter D33 of the socket portion 33 of the second concrete pipe 30. For this reason, the spigot portion 12 cannot be inserted directly into the socket portion 33.

The connection pipe 10 of this embodiment further includes a conversion section 40. The conversion section 40 is a steel pipe (steel pipe collar) and has a first fitting section 41 and a second fitting section 42. The outer diameter D41 of the first fitting section 41 is equal to or slightly larger than the inner diameter D12a of the spigot section 12, and can be pressed into the inner peripheral surface 12a of the spigot section 12 with a predetermined tightening margin. The outer diameter D42 of the second fitting section 42 is equal to the outer diameter D32 of the spigot section 32 of the second concrete pipe 30 and smaller than the outer diameter D12 of the spigot section 12. Therefore, the second fitting section 42 can be fitted into the socket section 33.

First, at the construction site where the connecting pipe 10 and the second concrete pipe 30 are to be connected, a lubricant is applied to the outer circumferential surface of the conversion section 40. Next, the conversion section 40 is attached to the connecting pipe 10 by inserting the first fitting section 41 into the inner circumferential surface 12a of the spigot section 12. Then, the connecting pipe 10 to which the conversion section 40 is attached is pulled toward the socket section 33, and the second fitting section 42 is inserted into the socket section 33. In this way, the first fitting section 41 of the conversion section 40 can be connected to the inner circumferential surface 12a of the spigot section 12, and the second fitting section 42 can be connected to the socket section 33. Therefore, the spigot section 12 and the socket section 33 can be connected by interposing the conversion section 40 between them.

[Action and effect of connecting pipe]
3 and 4, the socket portion 13 of the connecting pipe 10 has two inner diameters D13, D14, that is, the large diameter portion 14 and the small diameter portion 15, and therefore can be connected to both the spigot portion 22 of the first concrete pipe 20 and the spigot portion 32 of the second concrete pipe 30. Therefore, the connecting pipe 10 can be used more generally than a connecting pipe having a socket portion that can only be connected to one type of concrete pipe.

As explained above in Figures 5 and 6, the spigot portion 12 of the connecting pipe 10 can be connected to the socket portion 23 of the first concrete pipe 20, and can also be connected to the socket portion 33 of the second concrete pipe 30 via the conversion portion 40.

The connecting pipe 10 allows the first concrete pipe 20 and the second concrete pipe 30, each of which has a shape and size based on different standards, to be easily connected without connecting them via a manhole or by wrapping them in cast-in-place concrete.

The connecting pipe 10 is a so-called round pipe, and the cross-sectional shape perpendicular to the pipe axis direction of the connecting pipe 10 is cylindrical. By making the cross-sectional shape of the connecting pipe 10 cylindrical, there are advantages such as the area of the through hole 61a drilled in the manhole 60 when connecting to the manhole 60 described later being reduced, and flexible joints such as boots being easily attached.

The first embodiment of the present disclosure has been described above, but the present disclosure can be modified in various ways in addition to the above-described form. Below, other embodiments of the present disclosure (second to fourth embodiments) will be described. In the second and subsequent embodiments, the same reference numerals will be used to designate configurations similar to those of the first embodiment, and descriptions thereof will be omitted.

Second Embodiment
The spigot portion 12 of the connecting pipe 10 in the first embodiment can be directly connected to the socket portion 23 of the first concrete pipe 20, and a conversion portion 40 is attached when connecting to the second concrete pipe 30. In contrast, the spigot portion 121 of the connecting pipe 10a in the second embodiment can be directly connected to the second concrete pipe 30, and a conversion portion 50 is attached when connecting to the first concrete pipe 20. The configuration of the connecting pipe 10a will be described below with reference to Figures 7 and 8. Note that the socket portion 13 of the connecting pipe 10a is the same as that in the first embodiment, and therefore will not be illustrated or described.

Figure 7 shows how the spigot portion 121 of the connecting pipe 10a is connected to the socket portion 33 of the second concrete pipe 30. Figure 7(a) shows the state before connection, and Figure 7(b) shows the state after connection. The outer diameter D121 of the spigot portion 121 of the connecting pipe 10a is equal to the outer diameter D32 of the spigot portion 32 of the second concrete pipe 30. Therefore, the spigot portion 121 can fit into the socket portion 33 (inner diameter D33) of the second concrete pipe 30.

First, at the construction site where the second concrete pipe 30 and the connecting pipe 10a are to be connected, a lubricant is applied to the outer peripheral surface 121b. Next, the spigot portion 121 is inserted into the socket portion 33. The outer peripheral surface 121b of the spigot portion 121 is inserted up to the other end of the inner peripheral surface 33a in the pipe axial direction (or to a position slightly to one side of that end in the pipe axial direction) as shown in FIG. 7(b).

Figure 8 shows how the spigot portion 121 of the connecting pipe 10a is connected to the socket portion 23 of the first concrete pipe 20. Figure 8(a) shows the state before connection, and Figure 8(b) shows the state after connection. The outer diameter D121 of the spigot portion 121 of the connecting pipe 10a is smaller than the outer diameter D22 of the spigot portion 22 of the first concrete pipe 20. Therefore, even if the spigot portion 121 is inserted directly into the socket portion 23, a gap will be created between the outer peripheral surface 121b and the inner peripheral surface 23a, and the spigot portion 121 will not be able to fit into the socket portion 23.

The connection tube 10a of this embodiment further includes a conversion section 50. The conversion section 50 is a rubber cap having a cylindrical shape. The conversion section 50 has a function of filling the gap that occurs between the outer peripheral surface 121b and the inner peripheral surface 23a. Specifically, the inner peripheral surface 50a of the conversion section 50 has an inner diameter D51 that can be fitted with the outer peripheral surface 121b of the spigot section 121. In addition, the outer peripheral surface 50b of the conversion section 50 has an outer diameter D52 that can be fitted with the inner peripheral surface 23a of the socket section 23.

When connecting the connection pipe 10a and the first concrete pipe 20, the conversion part 50 is fitted to the outer peripheral surface 121b of the spigot part 121 at the construction site. Then, the spigot part 121 with the conversion part 50 fitted is inserted into the socket part 23. The conversion part 50 fills the gap between the outer peripheral surface 121b and the inner peripheral surface 23a, so the spigot part 121 and the socket part 23 are connected via the conversion part 50.

As explained above in Figures 7 and 8, the spigot portion 121 of the connecting pipe 10a can be connected to the socket portion 33 of the second concrete pipe 30, and can also be connected to the socket portion 23 of the first concrete pipe 20 via the conversion portion 50. Therefore, the connecting pipe 10a can easily connect the first concrete pipe 20 and the second concrete pipe 30, each of which has a shape and dimensions based on different standards.

Third Embodiment
The connecting pipes 10, 10a of the first and second embodiments are used to connect the first concrete pipe 20 and the second concrete pipe 30. In contrast, the connecting pipe 10b of the third embodiment is connected to the first concrete pipe 20 or the second concrete pipe 30 on one side in the pipe axis direction (the socket portion 13 side) and to the manhole 60 on the other side in the pipe axis direction (the spigot portion 122 side). The configuration of the connecting pipe 10b will be described below with reference to Fig. 9. Note that the socket portion 13 of the connecting pipe 10b is the same as that of the first embodiment, and therefore will not be illustrated or described.

Figure 9 is a diagram showing how the spigot portion 122 of the connecting pipe 10b is connected to the through hole 61a of the manhole 60. Figure 9(a) shows the state before connection, and Figure 9(b) shows the state after connection. The manhole 60 is a vertical hole used for purposes such as connecting and inspecting pipes, such as a manhole or a sewage manhole. The manhole 60 has a cylindrical or square tube-shaped side wall 61 that extends vertically, and a bottom wall 62. The side wall 61 has a circular through hole 61a for connecting the connecting pipe 10b.

The outer peripheral surface 122b of the spigot portion 122 of the connecting pipe 10b has a perfectly circular cross-sectional shape. The outer peripheral surface 122b is continuous with the outer peripheral surface 11b of the pipe body 11 without any step, and is not narrowed like the outer peripheral surface 12b of the spigot portion 12 of the first embodiment. In other words, the spigot portion 122 has a straight shape. The outer diameter D122 of the spigot portion 122 is smaller than the inner diameter D61 of the through hole 61a of the mandrel 60. Therefore, the spigot portion 122 can be inserted into the through hole 61a as shown in FIG. 9(b).

The connecting pipe 10b can be connected to the first concrete pipe 20 or the second concrete pipe 30 at the socket portion 13. It can also be connected to the manhole 60 at the spigot portion 122. Therefore, the connecting pipe 10b can easily connect the manhole 60 to either the first concrete pipe 20 or the second concrete pipe 30, each of which has a shape and size based on different standards.

Fourth Embodiment
The connecting pipe 10b of the third embodiment may be manufactured by cutting the connecting pipe 10 of the first embodiment midway.
FIG. 10 is an explanatory diagram showing connection structures 1a and 1b according to the fourth embodiment and a manufacturing method of the connection structures 1a and 1b.

Refer to FIG. 10(a). First, the connection pipe 10 is molded, and the connection pipe 10 is cut into one side and the other side in the tube axis direction at the cutting line C1, as shown in FIG. 10(b), and is divided into the connection pipe 10b on one side in the tube axis direction and the connection pipe 10c on the other side in the tube axis direction. The connection pipe 10b has the same structure as the connection pipe 10b described in the third embodiment. The connection pipe 10c has a tube body 11, a spigot portion 123, and a spigot portion 12. That is, the connection pipe 10c has spigot portions (spouts) at both ends. The outer peripheral surface 123b of the spigot portion 123 has the same circular cross-sectional shape and outer diameter D122 as the spigot portion 122. Therefore, the spigot portion 123 can be inserted into the through hole 61a (inner diameter D61) of the manhole 60.

As described above, after forming the connecting pipe 10, the connecting pipe 10 is cut to manufacture the connecting pipes 10b and 10c, thereby reducing the number of concrete molding forms required to manufacture the connecting pipes 10, 10b, and 10c. By preparing one form for the connecting pipe 10, there is no need to prepare separate forms for the connecting pipes 10b and 10c, and therefore manufacturing costs can be reduced.

Refer to Figure 10(c). The connection structure 1a includes a connection pipe 10b, a first concrete pipe 20 having a spigot portion 22 connected to a socket portion 13 of the connection pipe 10b, and a manhole 60 connected to the spigot portion 122 of the connection pipe 10b (the other end of the connection pipe 10b in the pipe axis direction).

The connection structure 1b also includes a connection pipe 10c, a first concrete pipe 20 having a socket portion 23 connected to the spigot portion 12 of the connection pipe 10c, and a manhole 60 connected to the spigot portion 123 of the connection pipe 10c (one end of the connection pipe 10c in the pipe axis direction).

Here, the first concrete pipe 20 has a thick pipe portion 24, and therefore has a cross-sectional shape that is circular at the top and trapezoidal at the bottom. Therefore, if the first concrete pipe 20 is directly connected to the manhole 60, it is necessary to form a circular through-hole 61a in the manhole 60 that is larger than the cross-sectional shape of the first concrete pipe 20, insert the first concrete pipe 20, and fill the gap with cast-in-place concrete or the like. For this reason, it is more difficult to connect the first concrete pipe 20 to the manhole 60 than a concrete pipe (a circular pipe) with a cylindrical cross-sectional shape such as the second concrete pipe 30.

In contrast, in the connection structure 1a, the spigot portion 22 side of the first concrete pipe 20 and the manhole 60 are connected via the connection pipe 10b. In the connection structure 1b, the socket portion 23 side of the first concrete pipe 20 and the manhole 60 are connected via the connection pipe 10c. Since the cross-sectional shape of the outer peripheral surfaces 122b, 123b of the spigot portions 122, 123 of the connection pipes 10b, 10c is a perfect circle, the area of the through hole 61a can be reduced, and the manhole 60 can be connected with a smaller gap between the outer peripheral surfaces 122b, 123b and the through hole 61a.

Here, the crack load of the connecting pipes 10b and 10c is set to a value closer to the crack load of the first concrete pipe 20 than the crack load of the second concrete pipe 30. In this embodiment, the connecting pipes 10b and 10c are originally placed in a location (e.g., a deeper location) that connects the first concrete pipe 20 and the manhole 60. Therefore, the piping buried in that location is required to have the same strength (e.g., crack load) as the first concrete pipe 20. For example, the second concrete pipe 30 has a lower strength than the first concrete pipe 20, so if it is buried in that location, it will lack strength and will need reinforcement such as concrete lining.

In contrast, the crack load of the connecting pipes 10b, 10c in this embodiment is close to the crack load of the first concrete pipe 20 (for example, the same value as the crack load of the first concrete pipe 20), so the connecting pipes 10b, 10c can be installed at the same depth as the first concrete pipe 20 without reinforcing them.

[Modifications]
[Connecting pipe without cylindrical section]
Fig. 11 is a diagram showing how the spigot portion 32 of the second concrete pipe 30 is connected to the socket portion 13 of the connecting pipe 10 according to a modified example of the first embodiment. Fig. 11(a) shows the state before connection, and Fig. 11(b) shows the state after connection.

This modified example differs from the first embodiment in that the connecting pipe 10 does not have a cylindrical portion 17 and that a gasket 34 is provided on the spigot portion 32 of the second concrete pipe 30, but in other respects it is the same. The cylindrical portion 17 does not have to be provided from the beginning, or the connecting pipe 10 may be configured so that the cylindrical portion 17 is provided on the small diameter portion 15 when shipped from the factory and is removed from the small diameter portion 15 immediately before construction.

The second concrete pipe 30 further includes a gasket 34. The gasket 34 is a rubber sealing member provided along the circumferential direction of the outer circumferential surface 32b of the spigot portion 32. The gasket 34 has the function of improving water-stopping properties by deforming when the spigot portion 32 is connected to the socket portion 13 of the connecting pipe 10 or the socket portion 33 of another second concrete pipe 30. The outer diameter of the gasket 34 is larger than the inner diameter D33, and is, for example, 713 mm.

First, at the construction site where the second concrete pipe 30 and the connecting pipe 10 are to be connected, a lubricant is applied to the outer surface 32b and the gasket 34. Next, the spigot portion 32 is inserted into the socket portion 13. The outer surface 32b and the gasket 34 of the spigot portion 32 are in sliding contact with the tip portion 16a of the gasket 16, and are inserted to the other end of the small diameter portion 15 in the pipe axis direction (or to a position slightly to one side of that end in the pipe axis direction) as shown in FIG. 11(b).

When the spigot portion 32 is inserted, the gasket 34 is deformed by being sandwiched between the outer peripheral surface 32b and the small diameter portion 15. The gasket 34 can seal the gap between the small diameter portion 15 and the outer peripheral surface 32b.

In this modified example, the gasket 16 that seals the gap between the spigot portion 22 of the first concrete pipe 20 and the connecting pipe 10 is provided on the connecting pipe 10 side (large diameter portion 14), and the gasket 34 that seals the gap between the spigot portion 32 of the second concrete pipe 30 and the connecting pipe 10 is provided on the second concrete pipe 30 side (outer surface 32b of spigot portion 32). With this configuration, whether the spigot portion 22 of the first concrete pipe 20 is inserted into the connecting pipe 10 or the spigot portion 32 of the second concrete pipe 30 is inserted into the connecting pipe 10, the gasket 16 or 34 can be used to seal the gap while sealing the gap.

If the gasket 34 were provided on the connecting pipe 10 side (e.g., the small diameter section 15), the problem would arise that when the spigot section 22 of the first concrete pipe 20 is inserted into the connecting pipe 10, the gasket 34 would be exposed directly inside the pipeline. In contrast, the gasket 34 in the first embodiment and this modified example is provided on the second concrete pipe 30 side, so that when the spigot section 22 of the first concrete pipe 20 is inserted into the connecting pipe 10, the gasket 34 can be prevented from being exposed inside the pipeline.

[Second concrete pipe without gasket]
Fig. 12 is a diagram showing how the spigot portion 32 of the second concrete pipe 30 is connected to the socket portion 13 of the connecting pipe 10d according to a modified example of the first embodiment. Fig. 12(a) shows the state before connection, and Fig. 12(b) shows the state after connection.

This modified example differs from the first embodiment in that the connecting pipe 10d does not have a cylindrical portion 17 and that the inner diameter D14a of the small diameter portion 15a of the connecting pipe 10d is smaller than the inner diameter D14 of the small diameter portion 15 of the first embodiment, but is otherwise the same. The inner diameter D14a is slightly larger than the outer diameter D32 of the spigot portion 32, and is, for example, 692 mm.

First, at the construction site where the second concrete pipe 30 and the connecting pipe 10d are to be connected, adhesive is applied to the outer circumferential surface 32b. Next, the spigot portion 32 is inserted into the socket portion 13. The outer circumferential surface 32b of the spigot portion 32 is inserted to the other end of the small diameter portion 15a in the pipe axis direction (or to a position slightly to one side of that end in the pipe axis direction) as shown in FIG. 12(b) while being in sliding contact with the tip portion 16a of the gasket 16.

After the spigot portion 32 is inserted, the adhesive applied to the outer peripheral surface 32b of the spigot portion 32 hardens by drying or the like while bonding the outer peripheral surface 32b to the small diameter portion 15. This makes it possible to waterproof the gap between the small diameter portion 15 and the outer peripheral surface 32b.

In this modified example, the inner diameter D14a of the small diameter portion 15a is smaller than the inner diameter 14 of the small diameter portion 15 in the first embodiment. Therefore, the difference (D13-D14a) between the inner diameter D13 of the large diameter portion 14 and the inner diameter 14a of the small diameter portion 15a is greater than the difference (D13-D14) between the inner diameter D13 of the large diameter portion 14 and the inner diameter 14 of the small diameter portion 15. In other words, the step between the large diameter portion 14 and the small diameter portion 15a is greater. This configuration makes it easier to cast the two-stage structure of the large diameter portion 14 and the small diameter portion 15a in concrete.

In addition, the small diameter portion 15a can be fitted to the spigot portion 32 by contacting the outer peripheral surface 32b of the spigot portion 32 or the adhesive applied to the outer peripheral surface 32b. This eliminates the need for a gasket 34, and reduces the number of parts required for installation.

In the above first embodiment, an example was described in which the spigot portion 12 of the connecting pipe 10 is connected to the socket portion 23, 33 of the first concrete pipe 20 or the second concrete pipe 30. However, the spigot portion 12 of the connecting pipe 10 may also be connected to the manhole 60. Since the outer peripheral surface 12b of the spigot portion 12 has a perfectly circular cross-sectional shape, it can be easily connected to the manhole 60, similar to the connecting pipe 10b of the third embodiment.

In this way, the connecting pipe 10 can be used more generally to connect different types of concrete pipes 20, 30 together, or to connect the concrete pipe 20 or 30 to a manhole 60.

In the above first embodiment, an example was described in which the socket portion 13 of the connection pipe 10 is formed with a large diameter portion 14 and a small diameter portion 15. In other words, the socket portion 13 has a two-stage structure. With this structure, the socket portion 13 of the connection pipe 10 can fit two types of spigot portions 22, 32, each of which has a different outer diameter. However, the socket portion 13 may have a structure of three or more stages.

For example, the socket portion 13 may be formed with a large diameter portion 14, a medium diameter portion, and a small diameter portion 15. The medium diameter portion is a region having an inner diameter smaller than the large diameter portion 14 and larger than the small diameter portion 15, and is located between the large diameter portion 14 and the small diameter portion 15 in the tube axial direction. By configuring the socket portion 13 in this way, three types of spigot portions each having a different outer diameter can be fitted into the socket portion 13, making it more versatile.

In the first embodiment described above, the first concrete pipe 20 is a pedestal pipe, and the second concrete pipe 30 is a Hume pipe. However, the implementation of the present disclosure is not limited to this, and the first concrete pipe 20 and the second concrete pipe 30 may be concrete pipes having different outer dimensions at the same nominal diameter according to standards. For example, the first concrete pipe 20 may be a high-strength pipe or a heavy-pressure pipe. A high-strength pipe is a concrete pipe that has a higher strength than a Hume pipe. A heavy-pressure pipe is a concrete pipe that includes a trapezoidal shape in part of its cross-sectional shape, similar to a pedestal pipe.

1: Connection structure, 1a: Connection structure, 1b: Connection structure, 10: Connection pipe, 10a: Connection pipe, 10b: Connection pipe, 10c: Connection pipe, 11: Pipe body, 12: Spigot portion, 121: Spigot portion, 122: Spigot portion, 123: Spigot portion, 13: Socket portion, 14: Large diameter portion, 15: Small diameter portion, 15a: Small diameter portion, 16: Gasket, 16a: Tip portion, 17: Cylindrical portion, 17a: Sponge material, 17b: Resin material, 2 0: First concrete pipe (pedestal pipe), 21: Pipe body, 22: Spigot part, 23: Socket part, 24: Pipe thickness part, 25: Gasket, 30: Second concrete pipe (Hume pipe), 31: Pipe body, 32: Spigot part, 33: Socket part, 34: Gasket, 40: Conversion part, 41: First fitting part, 42: Second fitting part, 50: Conversion part, 60: Column, 61: Side wall, 61a: Through hole, 61b: Through hole, 62: Bottom wall

Claims (14)

A connecting pipe to be connected to any two of a first concrete pipe, a second concrete pipe having a different standard from that of the first concrete pipe, and a manhole,
A connecting pipe socket portion is formed at one end in the pipe axial direction and is adapted to connect to a first spigot portion of a first concrete pipe or a second spigot portion of a second concrete pipe having an outer diameter smaller than that of the first spigot portion;
The connecting pipe socket portion is
A large diameter portion located at an end side of the tube axis direction;
a small diameter portion located inside the large diameter portion in the tube axis direction and having an inner diameter smaller than that of the large diameter portion,
the large diameter portion has an inner diameter capable of being fitted into the first spigot portion,
the small diameter portion has an inner diameter capable of being fitted with the second spigot portion,
a cylindrical portion provided along a circumferential direction of the small diameter portion and filling a step occurring between an inner circumferential surface of the first spigot portion that is fitted to the large diameter portion and the small diameter portion ,
Connecting tube. The cylindrical portion includes a sponge material that is crushed by the second spigot portion that is fitted into the small diameter portion.
The connecting pipe according to claim 1 . The cylindrical portion further includes a resin material that is impregnated into the sponge material in a fluid state and is hardenable after the sponge material is crushed.
The connecting pipe according to claim 2 . A first gasket is provided along a circumferential direction of the large diameter portion,
the large diameter portion has an inner diameter capable of fitting with the first spigot portion via the first gasket,
the first gasket has a tip portion capable of slidingly contacting an outer circumferential surface of the second spigot portion that is fitted into the small diameter portion,
The connecting pipe according to any one of claims 1 to 3. A second gasket is provided on the second spigot portion along a circumferential direction of an outer circumferential surface thereof,
the small diameter portion has an inner diameter capable of fitting with the second spigot portion via the second gasket;
The connecting pipe according to claim 4. A connecting pipe to be connected to any two of a first concrete pipe, a second concrete pipe having a different standard from that of the first concrete pipe, and a manhole,
A connecting pipe socket portion is formed at one end in the pipe axial direction and is adapted to connect to a first spigot portion of a first concrete pipe or a second spigot portion of a second concrete pipe having an outer diameter smaller than that of the first spigot portion;
The connecting pipe socket portion is
A large diameter portion located at an end side of the tube axis direction;
a small diameter portion located inside the large diameter portion in the tube axis direction and having an inner diameter smaller than that of the large diameter portion,
the large diameter portion has an inner diameter capable of being fitted into the first spigot portion,
the small diameter portion has an inner diameter capable of being fitted with the second spigot portion,
A first gasket is provided along a circumferential direction of the large diameter portion,
the large diameter portion has an inner diameter capable of fitting with the first spigot portion via the first gasket,
the first gasket has a tip portion capable of slidingly contacting an outer circumferential surface of the second spigot portion that is fitted into the small diameter portion,
Connecting tube. The small diameter portion has an inner diameter capable of fitting with the second spigot portion by contacting the outer circumferential surface of the second spigot portion or an adhesive applied to the outer circumferential surface of the small diameter portion.
The connecting pipe according to claim 6 . The first concrete pipe is a base pipe,
The second concrete pipe is a Hume pipe.
The connecting pipe according to any one of claims 1 to 7 . The cross-sectional shape perpendicular to the tube axis direction is a cylindrical shape.
The connecting pipe according to claim 8 . The strength is closer to the strength of the first concrete pipe than to the strength of the second concrete pipe.
The connecting pipe according to claim 8 or 9 . The pipe axial direction of the first concrete pipe is formed at the other end of the first concrete pipe, and the second concrete pipe is connected to the first socket portion of the first concrete pipe or the second socket portion of the second concrete pipe having an inner diameter smaller than that of the first socket portion .
The connecting pipe spigot portion has an outer diameter capable of being fitted into the first socket portion or the second socket portion.
The connecting pipe according to any one of claims 1 to 10. the connecting pipe spigot portion has an outer diameter capable of being fitted into the second socket portion,
A conversion part that is detachable from the outer circumferential surface of the connecting pipe spigot part is further provided,
The conversion portion has an inner diameter capable of fitting with the connection pipe spigot portion and an outer diameter capable of fitting with the first socket portion.
The connecting pipe according to claim 11. A connecting pipe according to claim 11 or 12;
the first concrete pipe connected to one of the connecting pipe socket portion and the connecting pipe spigot portion;
the second concrete pipe connected to the other of the connecting pipe socket portion and the connecting pipe spigot portion;
A connection structure comprising: A connecting pipe according to any one of claims 1 to 10;
The first concrete pipe to be connected to the connecting pipe socket portion, or the second concrete pipe to be connected to the connecting pipe socket portion;
the manhole connected to the other end of the connecting pipe in the tube axis direction;
A connection structure comprising:

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