Housing-type pipe fittings

Abstract

To improve the detection of construction defects. [Solution] The housing-type pipe joint 10 comprises an annular gasket 30 and a pair of housings 32, 32. The housing 32 comprises an internal space forming portion 50, a pair of arc-shaped claw portions 52, 52, a pair of flange portions 54, 54, a mating surface 56, an outer edge recess 58, and an outer edge protrusion 60. The mating surface 56 is located at the end of the claw portion 52. The mating surface 56 is perpendicular to the axis 120 direction of the hole 100 in the flange portion 54. The outer edge recess 58 is formed along the axis 120 direction of the hole 100. The outer edge protrusion 60 is formed adjacent to the outer edge recess 58. The outer edge protrusion 60 protrudes along the axis 120 direction of the hole 100. The flange portion 54 protrudes from the outside of the internal space forming portion 50 at a position further from the mating surface 56 than the outer edge recess 58. The outer edge recess 58 has a back side flat surface 80. The flat surface 80 on the back side is exposed.

Description

Technical Field

[0001] The present invention relates to a housing-type pipe joint.

Background Art

[0002] Patent Document 1 discloses a housing-type pipe joint. This housing-type pipe joint joins the pipe ends of two pipes facing each other via a gasket. Circumferential grooves are formed on the outer peripheral surfaces of the pipe ends of those two pipes. This housing-type pipe joint includes a gasket and a pair of housings. In the housing, a space on the inner surface for accommodating the gasket and arc-shaped claw portions at the inner diameter outer edge portions of two are formed. The arc-shaped claw portions engage with the circumferential grooves of the two pipes. At both ends of the housing, two flange portions are formed. Those flange portions have holes. Bolts for fastening the pair of opposing housings are inserted through the holes. The flange portion includes a mating surface, an L-shaped convex engaging portion, and an L-shaped concave engaging portion. The mating surface abuts against the opposing flange portions. The mating surface is perpendicular to the axial direction of the hole. The L-shaped convex engaging portion is connected to one of the claw portions. The L-shaped concave engaging portion is connected to the other of the claw portions. The L-shaped convex engaging portion of one flange portion and the L-shaped concave engaging portion of the other flange portion are arranged to face each other. The mating surface is formed at least inside and outside the hole. The mating surfaces are arranged on the same plane. According to the housing-type pipe joint disclosed in Patent Document 1, a housing-type pipe joint that does not have single-sided fastening can be provided even when bolt-nut tightening using a power tool is performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The housing-type pipe joint disclosed in Patent Document 1 has room for improvement in detecting faulty workmanship.

[0005] This invention was made to solve this problem. Its objective is to provide a housing-type pipe joint with improved detection of construction defects. [Means for solving the problem]

[0006] The housing-type pipe joint of the present invention will be described based on the drawings. The reference numerals in the drawings are used in this section to aid in understanding the content of the invention. The use of reference numerals in the drawings in this section is not intended to limit the content of the invention to the illustrated scope.

[0007] To achieve the above-mentioned objective, according to one aspect of the present invention, the housing-type pipe joint 10 comprises an annular gasket 30 and a pair of housings 32, 32. The gasket 30 is sandwiched and housed between the pair of housings 32, 32. The housing 32 comprises an internal space forming portion 50, a pair of arc-shaped claw portions 52, 52, a pair of flange portions 54, 54, and a mating surface 56. The internal space forming portion 50 forms an internal space for housing the gasket 30. The pair of arc-shaped claw portions 52, 52 each protrude from the opposing edges of the internal space forming portion 50. The pair of flange portions 54, 54 each have holes 100 through which bolts 34 are inserted. The pair of flange portions 54, 54 each protrude from the outside of the internal space forming portion 50 in opposite directions. The mating surface 56 is located at the ends of the claw portions 52. The mating surface 56 is perpendicular to the axis 120 direction of the hole 100. The housing 32 further has an outer edge recess 58 and an outer edge protrusion 60. The outer edge recess 58 is formed on the outer edge of the mating surface 56 at a position opposite to the inner space. The outer edge recess 58 is formed along the axis 120 direction of the hole 100. The outer edge protrusion 60 is formed on the outer edge of the mating surface 56 opposite to the inner space, adjacent to the outer edge recess 58. The outer edge protrusion 60 protrudes along the axis 120 direction of the hole 100. The outer edge recess 58 has a back side flat surface 80. The back side flat surface 80 is located on the back side of the inner space forming portion 50 that faces the inner space. The back side flat surface 80 extends along the axis 120 direction of the hole 100. The back side flat surface 80 is exposed. The flange portion 54 protrudes from the outside of the inner space forming portion 50 at a position further from the mating surface 56 than the outer edge recess 58.

[0008] The flange portion 54 protrudes from the outside of the inner space forming portion 50 at a position further from the mating surface 56 than the outer edge recess 58. The back flat surface 80 of the outer edge recess 58 is located on the back side of the inner space forming portion 50 that faces the inner space and extends along the axis 120 direction of the hole 100. In addition, the back flat surface 80 is exposed. This makes the mating surface 56 located at the end of the claw portion 52 easily visible from the outside of the housing 32. This easy visibility from the outside of the housing 32 makes it easy for the following to occur until the other outer edge protrusion 60 of the pair of housings 32, 32 begins to enter the space formed by one of the pair of outer edge recesses 58 of the housings 32, 32. This is the visibility of the risk of the gasket 30 being pinched between the mating surfaces 56 of each pair of claw portions 52, 52. In addition, the outer edge protrusion 60 is formed adjacent to the outer edge recess 58 on the outer edge of the mating surface 56 opposite to the inner space. The outer edge projection 60 protrudes along the axis 120 direction of the hole 100. As a result, when the pair of housings 32, 32 accommodate the gasket 30, the outer edge projection 60 of the other housing 32 enters the outer edge recess 58 of the other housing 32. By visually confirming whether the latter has entered the former, it becomes possible to detect faulty workmanship. Combined with the ease of visually confirming the risk of the gasket 30 being pinched, the detectability of faulty workmanship is improved.

[0009] Furthermore, it is desirable that the color of at least the portion of the back flat surface 80 that is in contact with the outer edge of the mating surface 56 is different from the color of the outer edge protrusion 60 on the side opposite to the inner space.

[0010] The color of at least the portion of the back flat surface 80 that is in contact with the outer edge of the mating surface 56 is different from the side of the outer edge protrusion 60 that is opposite to the inner space. As a result, it is easy to see that the back flat surface 80 is covered by the outer edge protrusion 60 as the outer edge protrusion 60 of one housing 32 enters the outer edge recess 58 of the other housing 32. Consequently, the detection of construction defects is improved.

[0011] Alternatively, it is desirable that at least the portion of the aforementioned back flat surface 80 that is in contact with the outer edge of the mating surface 56 be fluorescent in color.

[0012] Fluorescent colors appear brighter than non-fluorescent colors. As a result, it is easy to see that the outer edge protrusion 60 of one housing 32 enters the outer edge recess 58 of the other housing 32, and that the back flat surface 80 is covered by the outer edge protrusion 60. Consequently, the detection of construction defects is improved.

[0013] Furthermore, it is desirable that the shape and size of the portion of the outer edge protrusion 60 that protrudes from the mating surface 56 match the shape and size of the space formed by the outer edge recess 58.

[0014] The shape and size of the portion of the outer edge protrusion 60 that protrudes beyond the mating surface 56 coincide with the shape and size of the space formed by the outer edge recess 58. In this case, in the state described below, as the pair of housings 32, 32 move, one outer edge protrusion 60 of the pair of housings 32, 32 and the other outer edge recess 58 can easily come into contact. This state is when one outer edge protrusion 60 of the pair of housings 32, 32 enters the space formed by the outer edge recess 58 of the other housing 32. If one outer edge protrusion 60 of the pair of housings 32, 32 and the other outer edge recess 58 can easily come into contact, the occurrence of problems with the relative positional relationship between the pair of housings 32, 32 is prevented. Problems with the relative positional relationship between the pair of housings 32, 32 include, for example, the flange portions 54 of each housing 32, 32 getting too close together. Preventing problems with the relative positional relationship between pairs of housings 32, 32 will reduce the occurrence of construction defects.

[0015] Furthermore, it is desirable that the housing 32 described above further has a convex engaging portion 62 and a concave engaging portion 64. The convex engaging portion 62 protrudes along the axis 120 direction of the hole 100 from a position where it contacts one of the pair of claw portions 52, 52 and the mating surface 56. The concave engaging portion 64 is positioned symmetrically to the convex engaging portion 62 with respect to the surface described below. This surface passes through the center of the internal space forming portion 50 and is along the axis 120 direction of the hole 100. The concave engaging portion 64 forms a space into which the convex engaging portion 62 can fit.

[0016] The concave engaging portion 64 is positioned symmetrically to the convex engaging portion 62. As a result, when the pair of housings 32, 32 house the gasket 30, the convex engaging portion 62 of the other housing 32 enters the space formed by the concave engaging portion 64 of one housing 32. This reduces the possibility of the pair of housings 32, 32 shifting relative to each other in a direction perpendicular to the axis 120 of the hole 100.

[0017] Alternatively, it is desirable that the convex engaging portion 62 described above is connected to one of the pair of claw portions 52, 52. This improves workability in the following case, for example. This case is when circumferential grooves 520 are formed in each of the metal pipes 500, 500 that enter the gasket 30 and face each other, and the claw portion 52 fits into the circumferential groove 520, thereby preventing the metal pipes 500 from coming out of the gasket 30. If the convex engaging portion 62 is fitted into the circumferential groove 520 before fitting the claw portion 52 into the circumferential groove 520, the claw portion 52 connected to the convex engaging portion 62 can be smoothly fitted into the circumferential groove 520. Being able to smoothly fit the claw portion 52 into the circumferential groove 520 improves workability in fitting the claw portion 52 into the circumferential groove 520.

[0018] Alternatively, it is desirable that the outer edge recess 58 described above be positioned closer to the convex engaging portion 62 than the outer edge protrusion 60. In this case, it is desirable that the outer edge protrusion 60 be positioned closer to the concave engaging portion 64 than the outer edge recess 58.

[0019] The outer edge recess 58 is disposed at a position closer to the convex engaging portion 62 than the outer edge projection 60, and the outer edge projection 60 is disposed at a position closer to the concave engaging portion 64 than the outer edge recess 58. Thus, when the pair of housings 32, 32 are connected to each other, the outer edge projection 60 of the other of the pair of housings 32, 32 enters the space formed by the outer edge recess 58 disposed between the outer edge projection 60 of one of them and the convex engaging portion 62. Because of such entry, at the initial stage of the connection of the pair of housings 32, 32, the movable range of the outer edge projection 60 attempting to enter is restricted. Since the movable range is restricted, the entry of the outer edge projection 60 can proceed smoothly.

Advantages of the Invention

[0020] According to the present invention, the detectability of construction defects is improved.

Brief Description of the Drawings

[0021] [Figure 1] It is a diagram showing the configuration of a housing-shaped pipe joint according to an embodiment of the present invention. [Figure 2] It is a perspective view of a housing according to an embodiment of the present invention. [Figure 3] It is an enlarged view of the vicinity of an outer edge recess according to an embodiment of the present invention. [Figure 4] It is a side view of a pair of housings during tightening by a bolt and a nut according to an embodiment of the present invention. <000009@> [Figure 5] It is a side view of a pair of housings immediately after completion of tightening by a bolt and a nut according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0022] Hereinafter, a housing-shaped pipe joint according to an embodiment of the present invention will be described based on the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed descriptions thereof will not be repeated.

[0023] [Description of Structure] Figure 1 is a diagram showing the configuration of the housing-type pipe joint 10 according to this embodiment. The configuration of the housing-type pipe joint 10 according to this embodiment will be explained based on Figure 1.

[0024] The housing-type pipe joint 10 according to this embodiment joins two metal pipes 500, 500 with their ends facing each other. A circumferential groove 520 is formed on the outer surface of each of the ends of the two metal pipes 500, 500.

[0025] As shown in Figure 1, the housing-type pipe joint 10 according to this embodiment comprises an annular gasket 30, a pair of housings 32, 32, a pair of bolts 34, 34, and a pair of nuts 36, 36.

[0026] The gasket 30 seals the gap between the ends of the two metal pipes 500, 500. The gasket 30 according to this embodiment has a cylindrical portion 40 and a pair of annular portions 42, 42. The pair of annular portions 42, 42 are connected to one end and the other end of the cylindrical portion 40, respectively. When joining the two metal pipes 500, 500, one end of the pair of annular portions 42, 42 fits into the circumferential groove 520 of one of the pair of metal pipes 500, 500. The other end of the pair of annular portions 42, 42 fits into the circumferential groove 520 of the other pair of metal pipes 500, 500.

[0027] The pair of housings 32, 32 sandwich the gasket 30. This allows the gasket 30 to be housed within the housings 32, 32. The specific configuration of the housing 32 in this embodiment will be described later.

[0028] The pair of bolts 34, 34 connects the pair of housings 32, 32 that sandwich the gasket 30. The pair of nuts 36, 36 prevents the pair of bolts 34, 34 from coming loose from the pair of housings 32, 32. The specific configuration of the pair of bolts 34, 34 and the pair of nuts 36, 36 is the same as that of well-known bolts and nuts. Therefore, a detailed explanation is not repeated here.

[0029] Figure 2 is a perspective view of the housing 32 according to this embodiment. The configuration of the housing 32 according to this embodiment will be described based on Figure 2.

[0030] The housing 32 according to this embodiment includes an internal space forming portion 50, a pair of arc-shaped claw portions 52, 52, a pair of flange portions 54, 54, a pair of mating surfaces 56, 56, a pair of outer edge recesses 58, 58, a pair of outer edge protrusions 60, 60, a pair of convex engaging portions 62, 62, and a pair of concave engaging portions 64, 64.

[0031] The internal space forming portion 50 forms an internal space for accommodating the gasket 30. When the pair of housings 32, 32 sandwich the gasket 30, the gasket 30 is accommodated in the internal space formed by the internal space forming portion 50 of one of the housings 32, 32 and the internal space formed by the internal space forming portion 50 of the other housing 32, 32.

[0032] The pair of arc-shaped claw portions 52, 52 each protrude from the opposite edge of the inner space forming portion 50 that is in contact with the edge of the gasket 30. One end of the pair of claw portions 52, 52 fits into the circumferential groove 520 of one of the pair of metal pipes 500, 500. The other end of the pair of claw portions 52, 52 fits into the circumferential groove 520 of the other of the pair of metal pipes 500, 500.

[0033] Each pair of flange portions 54, 54 has a hole 100 formed in it for inserting a bolt 34. Each pair of flange portions 54, 54 protrudes from the outside of the inner space forming portion 50 in opposite directions.

[0034] The mating surfaces 56 are positioned at the ends of the internal space forming portion 50 and the claw portion 52. The mating surfaces 56 are perpendicular to the axis 120 of the hole 100. In this embodiment, "perpendicular" in the relationship between the mating surfaces 56 and the axis 120 of the hole 100 includes not only the case where the angle they make is exactly π / 2 radians, but also the case where the following condition is not permitted. This condition is one in which, under the circumstances described below, the pressure of the fluid flowing through the metal pipes 500, 500 causes any part of the gasket 30 to enter the gap between the opposing mating surfaces 56, 56. This condition is one in which a pair of housings 32, 32 sandwiches the gasket 30 that seals the gap between the ends of the two metal pipes 500, 500, and these pairs of housings 32, 32 are connected by a pair of bolts 34, 34 and a pair of nuts 36, 36.

[0035] The outer edge recess 58 is formed on the outer edge of the mating surface 56, on the side opposite to the inner surface space. The outer edge recess 58 is formed to extend along the axis 120 direction of the hole 100. The specific configuration of the outer edge recess 58 in this embodiment will be described later.

[0036] The outer edge projection 60 is formed on the outer edge of the mating surface 56, on the side opposite to the inner space. The outer edge projection 60 is formed adjacent to the outer edge recess 58. The outer edge projection 60 protrudes so as to extend along the axis 120 direction of the hole 100. The shape of the outer edge projection 60 is such that it can fit into the space formed by the outer edge recess 58. The outer edge recess 58 and the outer edge projection 60 are positioned closer to the mating surface 56 than the flange portion 54. That is, as shown in Figure 2, the flange portion 54 protrudes from the outside of the inner space forming portion 50 at a position further from the mating surface 56 than the outer edge recess 58 and the outer edge projection 60.

[0037] The convex engaging portion 62 protrudes along the axis 120 direction of the hole 100 from a position where it contacts one of the pair of claw portions 52, 52 and the mating surface 56.

[0038] The concave engaging portion 64 is positioned symmetrically to the convex engaging portion 62 with respect to the surface described below, with the mating surface 56 in between. This surface passes through the center of the inner space forming portion 50 and aligns with the axis 120 direction of the hole 100. In this embodiment, the axis 120 of the holes 100 of each pair of flange portions 54, 54 and the outer edge convex portion 60 are located on this surface. The concave engaging portion 64 forms a space into which the convex engaging portion 62 can be fitted.

[0039] Figure 3 is an enlarged view of the vicinity of the outer edge recess 58 according to this embodiment. The configuration of the outer edge recess 58 in this embodiment will be explained based on Figure 3.

[0040] As shown in Figure 3, the outer edge recess 58 according to this embodiment has a back flat surface 80, a pair of side wall forming surfaces 82, 82, and a bottom forming surface 84.

[0041] The back flat surface 80 is located on the back side of the surface of the inner space forming portion 50 that faces the inner space. The back flat surface 80 extends along the axis 120 direction of the hole 100. In this embodiment, the entire back flat surface 80 is fluorescent. "Fluorescent color" refers to a color that exhibits fluorescence. In this embodiment, the following coating film is formed on the entire back flat surface 80. This coating film emits light via photoluminescence. For this reason, the coating film contains a pigment capable of producing fluorescence. Because this coating film is formed, the entire back flat surface 80 is fluorescent.

[0042] The pair of sidewall-forming surfaces 82, 82 are connected to both sides of the back flat surface 80. Similar to the back flat surface 80, the pair of sidewall-forming surfaces 82, 82 extend along the axis 120 direction of the hole 100.

[0043] The bottom forming surface 84 is located in the area enclosed by the back flat surface 80 and the pair of side wall forming surfaces 82, 82. The bottom forming surface 84 extends along a direction perpendicular to the axis 120 of the hole 100.

[0044] As is clear from Figure 3, in this embodiment, the shape of the portion of the outer edge protrusion 60 that protrudes beyond the mating surface 56 matches the shape of the space formed by the outer edge recess 58. In addition, in this embodiment, the size of the portion of the outer edge protrusion 60 that protrudes beyond the mating surface 56 matches the size of the space formed by the outer edge recess 58. As a result, when one outer edge protrusion 60 of the pair of housings 32, 32 enters the space formed by the outer edge recess 58 of the other housing 32, one outer edge protrusion 60 of the pair of housings 32, 32 fits into the other outer edge recess 58 of the pair of housings 32, 32. The shape accuracy and dimensional accuracy of the outer edge recess 58 and outer edge protrusion 60 do not need to be more than sufficient to prevent problems from occurring in the interconnection of the pair of housings 32, 32. An example of such a problem is that if one pair of flange portions 54, 54 of each pair of housings 32, 32 get too close to each other, the other pair will separate.

[0045] [Instructions on how to connect] Next, a method for connecting two metal pipes 500, 500 using the housing-type pipe joint 10 according to this embodiment will be described.

[0046] The worker inserts one end of the two metal pipes 500, 500 into the gasket 30. Then the worker inserts the other end of the two metal pipes 500, 500 into the gasket 30.

[0047] Next, the worker places the gasket 30 between the pair of housings 32, 32. As a result, one of the pair of claws 52, 52 on the housings 32, 32 fits into the circumferential groove 520 on one of the pair of metal pipes 500, 500. The other of the pair of claws 52, 52 fits into the circumferential groove 520 on the other of the pair of metal pipes 500, 500. Once the gasket 30 is in place, the holes 100 in the flange portions 54 of each pair of housings 32, 32 face each other.

[0048] In this state, the worker inserts a bolt 34 through the holes 100, 100 of the opposing flange portions 54 of each housing 32, 32. Once the bolt 34 has passed through the holes 100, 100, the worker attaches a nut 36 to the bolt 34. This connects one pair of opposing flange portions 54 of each housing 32, 32. Next, the worker connects the remaining pair of flange portions 54 of each housing 32, 32 using the same procedure. Then, the worker tightens the opposing flange portions 54, 54 with the bolt 34 and nut 36.

[0049] Figure 4 is a side view of a pair of housings 32, 32 being tightened with a bolt 34 and a nut 36. In Figure 4, the metal pipes 500, 500 are not shown. At this point, one of the outer edge recesses 58 of the pair of housings 32, 32 is not obstructed by the outer edge protrusion 60 of the other housing. The edge of the outer edge recess 58 and the tip of the outer edge protrusion 60 are in contact. Therefore, the flat back surface 80 of the outer edge recess 58 is visible.

[0050] Figure 5 is a side view of the pair of housings 32, 32 immediately after tightening with bolts 34 and nuts 36. In Figure 5 as well, the metal pipes 500, 500 are not shown. In this embodiment, once tightening with bolts 34 and nuts 36 is complete, one outer edge recess 58 of the pair of housings 32, 32 is completely obscured by the outer edge protrusion 60 of the other. Therefore, the flat surface 80 on the back side of the outer edge recess 58 is not visible.

[0051] [Effects of the housing-type pipe joint according to this embodiment] As described above, in the housing-type pipe joint 10 according to this embodiment, the flange portion 54 protrudes from the outside of the inner space forming portion 50 at a position further from the mating surface 56 than the outer edge recess 58. The back flat surface 80 of the outer edge recess 58 is located on the back side of the inner space forming portion 50 that faces the inner space and extends along the axis 120 direction of the hole 100. In addition, the back flat surface 80 is exposed. As a result, unlike, for example, when the mating surface 56 is located on the outside side of the housing 32 than the hole 100, the mating surface 56 located at the end of the claw portion 52 can be easily seen from the outside of the housing 32. Because this can be easily seen from the outside of the housing 32, it becomes easier to proceed as described below until the other outer edge protrusion 60 of the pair of housings 32, 32 begins to enter the space formed by one of the pair of outer edge recesses 58 of the housings 32, 32. This involves visually confirming the risk of the gasket 30 being pinched between the mating surfaces 56 of each pair of claw portions 52, 52. In addition, when the pair of housings 32, 32 accommodate the gasket 30, the outer edge protrusion 60 of the other housing 32 enters the outer edge recess 58 of the other housing 32. By visually confirming whether the latter is entering the former, it becomes possible to detect faulty workmanship. Combined with the ease of visually confirming the risk of the gasket 30 being pinched, the detectability of faulty workmanship is improved.

[0052] Furthermore, the color of the back flat surface 80 of the outer edge recess 58 in this embodiment is different from the color of the outer edge protrusion 60. Moreover, the color of the back flat surface 80 is fluorescent. Fluorescent colors appear brighter than non-fluorescent colors. As a result, it is easy to see that the back flat surface 80 is covered by the outer edge protrusion 60 as the outer edge protrusion 60 of one housing 32 enters the outer edge recess 58 of the other housing 32.

[0053] Furthermore, in the housing-type pipe joint 10 according to this embodiment, the shape and size of the portion of the outer edge protrusion 60 that protrudes from the mating surface 56 matches the shape and size of the space formed by the outer edge recess 58. In this case, when the pair of housings 32, 32 accommodate the gasket 30, if the outer edge protrusion 60 of one housing 32 and the outer edge recess 58 of the other housing 32 do not face each other, it becomes difficult for the former outer edge protrusion 60 to enter the space formed by the latter outer edge recess 58. On the other hand, when the pair of housings 32, 32 accommodate the gasket 30, if the outer edge protrusion 60 of one housing 32 and the outer edge recess 58 of the other housing 32 face each other, the former outer edge protrusion 60 can enter the space formed by the latter outer edge recess 58. This prevents relative misalignment between the pair of housings 32, 32 when the pair of housings 32, 32 accommodate the gasket 30.

[0054] In addition, in the following state, as the pair of housings 32, 32 move, one outer edge protrusion 60 of the pair of housings 32, 32 and the other outer edge recess 58 can easily come into contact. This state is when one outer edge protrusion 60 of the pair of housings 32, 32 enters the space formed by the outer edge recess 58 of the other housing 32. If one outer edge protrusion 60 of the pair of housings 32, 32 and the other outer edge recess 58 can easily come into contact, the occurrence of the following problem can be prevented. This problem is that when connecting the flange portions 54, 54, the bolts 34 and nuts 36 are tightened too much, causing one end of the pair of claw portions 52, 52 to come too close together. Preventing such problems from occurring reduces the occurrence of construction defects.

[0055] Furthermore, in the housing-type pipe joint 10 according to this embodiment, the concave engaging portion 64 is positioned symmetrically to the convex engaging portion 62. As a result, when the pair of housings 32, 32 house the gasket 30, the convex engaging portion 62 of the other housing 32 enters the space formed by the concave engaging portion 64 of one housing 32. This reduces the possibility of the pair of housings 32, 32 shifting relative to each other in a direction perpendicular to the axis 120 direction of the hole 100.

[0056] <Explanation of variations> The embodiments disclosed herein are illustrative in all respects. The scope of the present invention is not limited based on the embodiments described above, and various design modifications may be made without departing from the spirit of the invention.

[0057] For example, the specific form of the outer edge recess 58 is not limited to those described above. The entire outer edge recess 58 does not need to be fluorescent in color. However, in that case, it is desirable that the color of the portion of the back flat surface 80 that is in contact with the outer edge of the mating surface 56 is different from the color of the outer edge protrusion 60 on the side opposite to the inner space. However, if it does not interfere with external visibility, the color of the outer edge recess 58 may be the same as that of the outer edge protrusion 60. [Explanation of symbols]

[0058] 10…Housing-type pipe fittings 30…Gasket 32… Housing 34... Volts 36... Nut 40…Cylindrical section 42... Circular section 50...Inner space forming part 52… Nail area 54…Flange section 56… mating surface 58…Outer edge recess 60... Outer edge protrusion 62...Convex engaging portion 64...Concave engagement part 80... Flat surface on the back 82...Side wall forming surface 84…Bottom forming surface 100...hole 120...axis 500…Metal tube 520...Circumferential groove

Claims

1. An annular gasket, The system comprises a pair of housings in which the gasket is sandwiched and housed, The aforementioned housing, An internal space forming portion that forms an internal space for housing the gasket, A pair of arc-shaped claw portions protruding from opposite edges of the internal space forming portion, Each has a hole formed for inserting a bolt, and pairs of flange portions protruding from the outside of the internal space forming portion in opposite directions, A housing-type pipe joint having a mating surface positioned at the end of the claw portion and perpendicular to the axial direction of the hole, The aforementioned housing, An outer edge recess is formed on the outer edge of the mating surface at a position opposite to the inner surface space, and is formed along the axial direction of the hole, The mating surface on the opposite side of the inner surface space further has an outer edge projection that is formed adjacent to the outer edge recess and protrudes along the axial direction of the hole, The outer edge recess is located on the back side of the inner space forming portion that faces the inner space, and has a back side flat surface that extends along the axial direction of the hole and is exposed. A housing-type pipe joint characterized in that the flange portion protrudes from the outside of the internal space forming portion at a position further from the mating surface than the outer edge recess.

2. The housing-type pipe joint according to claim 1, characterized in that the color of at least the portion of the back flat surface that is in contact with the outer edge of the mating surface is different from the color of the outer edge protrusion on the side opposite to the inner surface space.

3. The housing-type pipe joint according to claim 2, characterized in that at least the portion of the flat surface on the back side that is in contact with the outer edge of the mating surface is fluorescent in color.

4. The housing-type pipe joint according to claim 1, characterized in that the shape and size of the portion of the outer edge protrusion that protrudes from the mating surface matches the shape and size of the space formed by the outer edge recess.

5. The aforementioned housing, A convex engaging portion that protrudes along the axial direction of the hole from a position where it contacts one of the pair of claw portions and the mating surface, The housing-type pipe joint according to claim 1, further comprising a concave engaging portion which is positioned symmetrically with respect to the convex engaging portion with respect to a surface passing through the center of the internal space forming portion and along the axial direction of the hole, and which forms a space into which the convex engaging portion can be fitted.

6. The housing-type pipe joint according to claim 5, characterized in that the convex engaging portion is connected to one of the pair of claw portions.

7. The outer edge recess is positioned closer to the convex engaging portion than the outer edge protrusion, The housing-type pipe joint according to claim 5, characterized in that the outer edge protrusion is positioned closer to the concave engagement portion than the outer edge recess.

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