Pipe joint

Abstract

To provide a pipe joint in which the rigidity of a portion with a contact surface is improved to make a function of a projection part more reliable, and which can be constructed even when a diameter of a through hole is out of a predetermined value and small.SOLUTION: A pipe joint 11 has a female threaded part 53 that is screwed into an outer peripheral surface of a spirally corrugated pipe 13, has a contact plate 55 having a contact surface 55a brought into contact with the periphery of a through hole 73 of an underground box 71, and comprises a projection part 52 that is provided on an inner peripheral side with respect to the contact surface 55a and on the outer peripheral side with respect to the female threaded part 53, and enters the through hole 73. The pipe joint connects pipe bodies by sandwiching the periphery of the through hole 73 in cooperation with a bell mouth 12 having a male threaded part 21 screwed into an inner peripheral surface of a pipe body 13 and a contact surface 22a brought into contact with the periphery of the through hole 73. A flange-shaped annular plate part 57 is formed at an end opposite to the projection part 52, and extends in an outer peripheral direction at a distance from the contact plate 55.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a pipe joint used for connecting a pipe body for protecting an electric wire to an underground box buried underground, such as a handhole or a manhole.

Background Art

[0002] This type of pipe joint is attached outside the underground box on the outer periphery of the pipe body inserted into the through hole of the underground box. The through hole is formed by drilling in the wall of the underground box, and the pipe joint has a contact surface that contacts the periphery of the through hole. The pipe body is connected to the through hole by sandwiching the periphery of the through hole between this contact surface and a bellmouth attached to the inner side of the wall as the terminal of the pipe body.

[0003] However, earth pressure is applied to the pipe body buried underground. Depending on how the earth pressure is applied, the pipe body protruding vertically from the wall surface of the underground box bends downward so as to sag at a portion away from the underground box. Due to this deformation, a gap may be formed between the pipe joint and the periphery of the through hole, and there is a risk that the water stoppage property cannot be maintained.

[0004] Therefore, the pipe body connection structure of Patent Document 1 below was devised.

[0005] This pipe body connection structure is provided with a cylindrical protrusion entering the through hole at the inner peripheral side portion of the contact surface that contacts the periphery of the through hole in the pipe joint. Even when the pipe body bends and the contact surface of the pipe joint tends to separate from the periphery of the through hole, the protrusion contacts the inner peripheral surface of the through hole and prevents displacement such that the pipe joint tilts, so that the water stoppage property can be maintained.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the portion having the contact surface is a plate-like shape that protrudes in a flange-like manner in the outer direction, while the portion opposite the projection is formed in a simple cylindrical shape. This portion should have high rigidity in order to ensure a firm tightening and to guarantee the action of the projection in preventing displacement of the pipe joint.

[0008] Furthermore, the through-holes in underground boxes may not be the desired size depending on the drilling blade used. Since the diameter of the protrusions formed on pipe fittings is set to a predetermined value, if the size of the through-hole is smaller than the size of the protrusion, the prepared pipe fittings cannot be used. If such a situation occurs at a construction site, it can lead to serious problems such as delays in the construction period.

[0009] Therefore, the main objective of this invention is to improve the rigidity of the portion having a contact surface, thereby making the function of the protrusion more reliable, and to also obtain other advantages, such as enabling construction even if the diameter of the through hole is outside a predetermined value. [Means for solving the problem]

[0010] The means for this is a pipe joint having a coupling portion that connects to the outer surface of a pipe body, and a contact plate having a contact surface that abuts around the through hole of the object to be connected, and a projection that penetrates the through hole at a portion on the inner circumference side of the contact surface and on the outer circumference side of the coupling portion, and which works in cooperation with a bell mouth having a coupling portion that connects to the inner surface of a pipe body and a contact surface that abuts around the through hole of the object to be connected to clamp the periphery of the through hole and connect the pipe body to the through hole, wherein a flange-shaped annular plate portion is formed at the end opposite to the projection, extending outward from the contact plate at a distance.

[0011] In this configuration, if the size of the through-hole to be connected is within a predetermined size or within an acceptable range, the pipe fitting is attached to the pipe body by the joint and the projection is inserted into the through-hole. In this state, the contact surface of the pipe fitting and the contact surface of the bell mouth are used to clamp the area around the through-hole. At this time, the annular plate portion is integrated with the contact plate behind the contact plate having a contact surface, and improves the rigidity of the portion on the annular plate side of the contact plate.

[0012] Furthermore, the annular plate portion can be used in place of a contact plate to perform a tightening function when the size of the through hole of the object to be connected is smaller than a predetermined value and the protrusion cannot be inserted, by reversing the front and back of the pipe joint.

[0013] Furthermore, the annular plate portion has a flange-like shape that protrudes outward, and the position of its outer surface is separated from the outer surface of the connecting pipe to improve operability, and even though it is plate-shaped, it works in cooperation with the contact plates that are spaced apart to make it easier to hold that part. [Effects of the Invention]

[0014] According to this invention, since an annular plate portion is provided behind the contact plate, the rigidity of the portion from the contact plate to the annular plate portion is improved, and the function of the projection inserted into the through hole of the object to be connected can be made reliable.

[0015] Furthermore, if the through-hole is too small to insert the protrusion, the pipe fitting can be reversed and the annular plate portion can be used as a contact plate to make the connection. Moreover, in this case, the portion from the annular plate portion to the contact plate has high rigidity, allowing for a tighter tightening and maintaining watertightness.

[0016] In addition, the annular plate portion that protrudes outward is easier to hold than when it is located closer to the outer surface of the pipe, thus improving the ease of installation and tightening. [Brief explanation of the drawing]

[0017] [Figure 1] Perspective view of a pipe joint. [Figure 2]Cross-sectional view showing the separated state of the pipe connection structure. [Figure 3] Cross-sectional view in the use state. [Figure 4] Perspective view of the pipe joint with the waterstop separated. [Figure 5] Front view, side view, and cross-sectional view of the pipe joint. [Figure 6] Cross-sectional view showing the pipe joint and the through hole. [Figure 7] Cross-sectional view in the use state. [Figure 8] Perspective view, front view, side view, and cross-sectional view of the pipe joint. [Figure 9] Perspective view, front view, side view, and cross-sectional view of the pipe joint. [Figure 10] Perspective view, front view, side view, and cross-sectional view of the pipe joint. [Figure 11] Perspective view, front view, side view, and cross-sectional view of the pipe joint. [Figure 12] Perspective view, front view, side view, and cross-sectional view of the pipe joint. [Figure 13] Perspective view, front view, side view, and cross-sectional view of the pipe joint.

Mode for Carrying Out the Invention

[0018] One embodiment for carrying out this invention will be described below with reference to the drawings.

[0019] Fig. 1 shows a perspective view of the pipe joint 11. This pipe joint 11 is for obtaining a pipe connection structure for connecting a pipe 13 with spiral waves (hereinafter referred to as "pipe body") to a ground box 71 to be connected, using a bell mouth 12 as shown in Fig. 2.

[0020] The pipe body 13 is for protecting the electric wires buried in the ground and is formed of synthetic resin. Spiral irregularities (spiral waves) are formed not only on the outer peripheral surface but also on the inner peripheral surface. This pipe body 13 is connected so that one end is fitted into a circular through hole 73 formed in the wall portion 72 of the ground box 71. In the connected state, as shown in Fig. 3, the pipe body 13 protrudes vertically from the outer side surface 72a of the wall portion 72 of the ground box 71.

[0021] The pipe fitting 11 is made of synthetic resin and is formed in a substantially cylindrical shape as shown in Figure 1, and has a through hole 11a on the inside through which the pipe body 13 passes. The cylindrical pipe fitting 11 can be divided into two parts in the longitudinal direction (axial direction), with one end in the axial direction being the main body portion 51 and the other end being the projection portion 52.

[0022] The inner circumferential surface of the main body 51 of the pipe fitting 11 has a female threaded portion 53 formed thereon, which serves as a connecting portion for screwing into the outer circumferential surface of the pipe body 13. This female threaded portion 53 is equipped with a sheet-like water-sealing material 54 that expands when it absorbs moisture.

[0023] The waterproofing material 54 can be a nonwoven fabric made of polyethylene terephthalate or the like that contains a water-swelling material that absorbs moisture and expands. For fixing to the female thread portion 53, it is best to attach the waterproofing material 54 cut to the required shape as shown in Figure 4, but the waterproofing material 54 can also be integrally molded when forming the pipe joint 11.

[0024] Figure 5 shows a side view, front view, and cross-sectional view of the pipe joint 11, with all waterproofing materials, including the aforementioned waterproofing material 54, omitted from the illustration. In Figure 5, (a) is the left side view, (b) is the front view, (c) is the right side view, and (d) is the AA cross-sectional view of (c). The dashed line in (a) indicates the cross-sectional shape at the BB cutting position in (d).

[0025] On the outer circumferential surface of the main body 51, at the end that connects to the underground box 71, that is, the end on the side of the projection 52, a contact plate 55 is formed that extends outward in a flange-like manner and has a larger diameter than the through hole 73. Here, "the side that connects to the underground box 71" indicates the direction in the intended use and is not an absolute meaning.

[0026] The contact plate 55 is an annular shape with a circular contour. The flat surface of this contact plate 55 on the side of the protrusion 52 is the contact surface 55a that abuts against the area around the through hole 73 on the outer surface 72a of the underground box 71. A waterproofing material 56 is also provided on the contact surface 55a. Therefore, the contact surface 55a indirectly abuts against the underground box 71 via the waterproofing material 56.

[0027] The waterproofing material 56 provided on the contact surface 55a is formed in an annular shape. The waterproofing material 56 may consist only of a water-swellable nonwoven fabric, as described above, but since the contact surface 55a is a part that comes into strong contact with the underground box 71 with rotation, it is preferable to have a two-layer structure with a rubber layer 56b on the back of the water-swellable nonwoven fabric layer 56a, as shown in Figure 4. By making the rubber layer 56b out of soft rubber and laminating it with the nonwoven fabric layer 56a, when the water-swellable nonwoven fabric layer 56a expands and exerts a tightening force, the rubber layer 56b can be compressed and deformed while still acting as a repulsive force. As a result, a firmer tightening is possible, and a better waterproofing state can be obtained.

[0028] On the outer surface of the main body 51, at the end opposite to the side connected to the underground box 71, a flange-shaped annular plate portion 57 is formed, extending outward from the contact plate 55. The meaning of "side connected to the underground box 71" here also indicates the direction in the originally intended use and is not absolute.

[0029] The axial length of the main body portion 51, which has the annular plate portion 57 and the contact plate 55, is set to be at least the length necessary to form the female screw portion 53, and also long enough to stabilize the contact plate 55 and the annular plate portion 57 when a fingertip or hand is hooked onto them.

[0030] The shape of the annular plate portion 57 is the same as that of the contact plate 55, and is an annular shape with a circular contour. The size of the annular plate portion 57 is also corresponding to the size of the contact plate 55. In other words, the annular plate portion 57 is sized to be in balance with the contact plate 55, and is formed to be the same size or similar in size. Even if the contour shapes of the annular plate portion 57 and the contact plate 55 are different, they can be similar in size if a part of their diameter is the same or similar.

[0031] In this example, the annular plate portion 57 is formed to the same size as the abutment plate 55, has the same shape, and is aligned parallel to the abutment plate 55.

[0032] A rib 58 is formed between the annular plate portion 57 and the contact plate 55, connecting them. The rib 58 extends parallel to the axial direction of the main body portion 51 and is arranged in multiples at equal intervals along the circumferential direction. In this example, there are four ribs 58. The height of the rib 58 is sufficient to adequately support the annular plate portion 57 and the contact plate 55, and more preferably, it is set to a height at which fingers or hands make contact when fingers or hands are placed on the outer circumference of the main body portion 51.

[0033] The flat surface of the annular plate portion 57 opposite to the contact surface 55a of the contact plate 55 is the contact surface 57a when used in reverse, and a waterproofing material 59 is provided on this contact surface 57a when used in reverse. This waterproofing material 59 may have the same structure as the waterproofing material 56 provided on the contact surface 55a of the contact plate 55. That is, the waterproofing material 59 may have a two-layer structure with a water-swellable nonwoven fabric layer 59a and a rubber layer 59b on the back.

[0034] The aforementioned projection 52 is integrally formed on the end of the main body 51 on the side having the contact plate 55, on the inner circumference side of the contact surface 55a and on the outer circumference side of the female screw portion 53. This projection 52 is cylindrical and is the part that enters the through hole 73.

[0035] As shown in Figure 6, the size of the outer circumferential surface of the projection 52, i.e., the outer diameter D1, is set to be slightly smaller by a few millimeters than the planned desired diameter D2 of the through hole 73.

[0036] The aforementioned female thread portion 53 is not formed on this projection 52, and the area in which the female thread portion 53 is formed is limited to the area between the contact plate 55 and the annular plate portion 57. The inner circumferential surface of the projection 52 has a smooth circumferential surface without irregularities.

[0037] The length L1 of the projection 52 is desirable to be longer in the intended use, but is set to be less than or equal to the thickness L2 of the wall portion 72 of the underground box 71. The "length L1 of the projection 52" referred to here is the length obtained by subtracting the thickness t of the waterproofing material 56 from the original length L3 of the projection 52, since the contact surface 55a is equipped with waterproofing material 56.

[0038] Note that the underground box 71 in the illustrated example has a wall section 72 that is thinner than usual, approximately 30 mm thick.

[0039] The thickness of the projection 52 is such that it has the desired rigidity and creates a gap between it and the outer surface of the pipe body 13 to be connected, regardless of the inner surface of the main body 51 (the radial position of the thread root of the female thread portion 53).

[0040] The bell mouth 12 is made of synthetic resin and has a cylindrical male threaded portion 21 as a connecting part that is screwed onto the inner circumferential surface of the pipe body 13. One end of this male threaded portion 21 has an annular contact plate 22 that protrudes outward in a flange-like manner and is larger than the through hole 73. The side of this contact plate 22 that has the male threaded portion 21 is a contact surface 22a that indirectly contacts the area around the through hole 73 on the inner surface 72b of the underground box 71. A water-sealing material 23 is also provided on this contact surface 22a.

[0041] To connect the pipe body 13 to the wall portion 72 of the underground box 71 using the pipe joint 11 described above, proceed as follows.

[0042] First, one end of the pipe body 13 is screwed into the pipe joint 11, and the projection 52 of the pipe joint 11 is inserted from the outer surface 72a side into the through hole 73 formed in the wall portion 72 of the underground box 71.

[0043] Next, the male threaded portion 21 of the bell mouth 12 is screwed into the inner surface 72b of the wall portion 72 of the underground box 71, and the contact surfaces 55a and 22a of the pipe joint 11 and the bell mouth 12 sandwich the area around the through hole 73 in the wall portion 72 in the thickness direction. In this way, the pipe joint 11 and the bell mouth 12 work together to connect the pipe body 13 into the through hole 73, and the pipe joint 11 and the pipe body 13 protrude vertically from the wall portion 72 as shown in Figure 3. At this time, the projection 52 of the pipe joint 11 has its outer surface close to the inner surface of the through hole 73 with a thin gap in between.

[0044] The main body 51 of the pipe joint 11 has a horizontal U-shaped cross-section with flanges at both ends of the cylindrical portion, making it highly rigid and easy to hold by hand. Furthermore, the annular plate portion 57, together with the contact plate 55, has an outer diameter larger than its inner diameter, allowing the hand holding it to be moved away from the pipe body 13, making it easy to rotate and apply force efficiently. As a result, the workability when screwing in the pipe joint 11 is good, and the work of tightening it to clamp the wall portion 72 of the underground box 71 can be performed smoothly.

[0045] After connection and burial in the ground, all the waterproofing materials 54, 56, and 59 absorb moisture from the ground and expand, creating a gap-free state in the waterproofing material 54, 56, and 59 sections, and strengthening the connection between each component 11, 12, and 13. The protrusion 52 of the pipe joint 11 is maintained in a state where it is inserted into the through hole 73 in a way that prevents relative displacement.

[0046] In this state, even if soil pressure is applied and a load is exerted on the pipe body 13 from above, causing the pipe body 13 to bend and deform, the protrusion 52 of the pipe joint 11 will be in contact with, or nearly in contact with, the inner circumferential surface of the through hole 73, thereby preventing relative displacement. This effect is also supplemented by the expansion force of the water-stopping materials 56 and 23 provided on the contact surfaces 55a and 22a.

[0047] In this way, the protrusion 52 prevents displacement within the through-hole 73 of the pipe joint 11, and the rigidity of the main body 51 having the contact plate 55 and the annular plate portion 57 is high. Therefore, even if a load that causes the pipe body 13 to bend downward is applied, the contact surface 55a of the pipe joint 11 will not be displaced significantly away from the periphery of the through-hole 73, and watertightness can be maintained.

[0048] The rigidity of the main body 51 is further increased by the presence of ribs 58 between the contact plate 55 and the annular plate 57, allowing for stronger clamping and thus more reliably achieving the above-mentioned effects.

[0049] Furthermore, since the connection between the pipe fitting 11 and the bell mouth 12 is made of threads, the connection can be made by rotation, making the connection work extremely easy. Moreover, since the annular plate portion 57 is formed in an annular shape and is sized to match the size of the contact plate 55, the main body portion 51 can be easily held and rotated with fingertips or hands, and rotational force can be efficiently applied. In addition, the ribs 58 also serve as an anti-slip feature during rotation, resulting in good workability.

[0050] If the size of the through-hole 73 in the underground box 71 is smaller than the planned size and the protrusion 52 cannot be inserted, the connection is made by pressing the contact surface 57a for reverse use against the outer surface 72a of the underground box 71, as shown in Figure 7. In other words, the pipe joint 11 is used in the opposite direction to the example in Figure 3 described above.

[0051] When used in this manner, the annular plate portion 57 and the contact plate 55 have their functions swapped, but their operation is the same. However, the protrusion 52 does not enter the through hole 73, so it remains exposed on the outside of the underground box 71.

[0052] However, as mentioned above, the main body 51 has high rigidity, so a firm fixing state can be obtained, and a good watertight state can be maintained. The screwing workability of the pipe joint 11 is also good, as mentioned above.

[0053] Furthermore, even if soil pressure is applied and the pipe body 13 bends downward, the inner surface of the projection 52 is smooth and free of irregularities, and there is a gap between it and the outer surface of the pipe body 13, so the pipe body 13 is not subjected to strong pressure due to deformation. As a result, when the annular plate portion 57 is used in reverse, it is possible to prevent large displacements that would cause the contact surface 57a of the annular plate portion 57 to separate from the outer surface 72a of the underground box 71 and create a gap, thereby maintaining watertightness.

[0054] In particular, if the length of the protrusion 52 is set to be shorter so that it can be connected to underground boxes 71 with thinner walls 72 than usual, as in the illustrated example of pipe joint 11, it is less susceptible to the effects of deformation of the pipe body 13.

[0055] As described above, pipe fittings 11 are available in multiple types depending on the diameter of the pipe body 13 to be connected. However, not all types of pipe fittings 11 have similar shapes; the dimensions of each part differ depending on the size.

[0056] Below, using Figures 8 to 13, we will explain examples of pipe fittings 11 with different dimensions depending on the pipe diameter. In this explanation, parts identical to those described above are denoted by the same reference numerals, and detailed explanations of them are omitted.

[0057] Figures 8 to 13 show the external appearance and cross-section of the pipe joint 11 with all water-stopping materials 54, 56, and 59 omitted from the illustration, and are displayed in the same format in all figures. In the figures, (a) is a perspective view, (b) is a left side view, (c) is a front view, (d) is a right side view, and (e) is a central vertical cross-section of the right side view. The dashed line in (a) indicates the cross-sectional shape at the position indicated by the dashed line in (e), which is the location where the female thread portion 53 has threads.

[0058] Furthermore, the length of the projection 52 in all figures is the same as the length of the projection 52 in Figure 5, because the thickness of the wall portion 72 to be connected is the same as in the case of the pipe joint 11 shown in Figure 5.

[0059] Figure 8 shows a pipe fitting 11 with a smaller diameter than the pipe fitting 11 in Figure 5, and Figures 9 to 13 show pipe fittings 11 with progressively larger diameters than the pipe fitting 11 in Figure 5.

[0060] As shown in these figures, as the diameter increases, the length of the main body 51 increases in stages, and the ratio of the length of the main body 51 to the length of the projection 52 increases in stages. Since the length of the projection 52 is the same for all pipe fittings 11, the projection 52 is longer and thinner for smaller diameters, and thicker and shorter for larger diameters.

[0061] The thickness of the waterproofing material provided in pipe fittings 11 of different sizes is the same.

[0062] The above configuration is one embodiment of the present invention, and the present invention is not limited to the above configuration; other configurations can also be adopted.

[0063] For example, the tube body 13 may be a spiral-shaped tube or an independent-peak type tube. [Explanation of Symbols]

[0064] 11…Pipe fittings 12... Bellmouth 13… Tube with spiral wave 21...Male threaded part 22a...Abutment surface 52… protrusion 53...Female thread section 55...Abutting plate 55a…Abutting surface 57... Annular plate section 57a... Contact surface when used in reverse 58... Rib 59...Waterproofing material 71...Underground box 73…Through hole

Claims

1. a pipe fitting having a coupling portion coupled to the outer peripheral surface of a pipe body, and an abutment plate having an abutment surface that abuts against the periphery of a through hole to be connected, and a protrusion that enters the through hole at a position inner peripherally of the abutment surface and outer peripherally of the coupling portion, and having a coupling portion coupled to the inner peripheral surface of the pipe body, and cooperating with a bell mouth having an abutment surface that abuts against the periphery of the through hole to connect the pipe body to the through hole by clamping the periphery of the through hole, A flange-shaped annular plate portion is formed at the end opposite to the protrusion portion and projects outward from the contact plate at a distance. Pipe fittings.

2. The annular plate portion is formed in an annular shape with a circular contour.

2. The pipe fitting according to claim 1.

3. The annular plate portion is formed to a size corresponding to the size of the abutment plate.

3. A pipe joint according to claim 1 or claim 2.

4. A rib is formed between the annular plate portion and the abutment plate to connect them. A pipe joint according to any one of claims 1 to 3.

5. The connecting portion is formed only in a range corresponding to the portion between the contact plate and the annular plate portion. A pipe joint according to any one of claims 1 to 4.

6. A water-stopping material is provided on the surface of the annular plate portion opposite to the contact surface. A pipe joint according to any one of claims 1 to 5.

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