JPH0480276B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pipe joint for connecting corrugated pipes.

[Conventional technology]

This type of pipe joint was developed for economical piping by cutting long corrugated pipes (hereinafter referred to as pipes) to the required length at piping sites. To make the connection, after cutting the tube, cut off the protective covering of the tube with a length equal to or longer than the length of the sleeve added to the crushing allowance of the waveform at the tip of the tube, attach the sleeve to the tube, tighten the cap nut, and then tighten the sleeve. A method of inserting it into the tapered part of the joint body is adopted. However, in this method, after the pipes are connected, the pipes with their protective coatings cut off are exposed from the ends of the cap nuts, so there is a risk of corrosion of the pipes, and the long-term leak-proofing performance remains unsatisfactory.

[Problem that the invention seeks to solve]

In view of the above points, it is an object of the present invention to provide a pipe joint that has a short cut length of the protective coating of the pipe, is easy to construct, and has long-term leak-proof performance without exposed pipe parts. It is something to do.

[Means for solving problems]

The gist of the present invention is a pipe joint for connecting thin-walled metal corrugated pipes having an outer surface protective coating layer, which has a male thread on the outer periphery of one end, and a male thread on the inner periphery with a small angle facing toward the back. The inner periphery of the other end has a through hole smaller in diameter than the tapered hole, and a pipe receiving wall is provided at the boundary between the through hole and the tapered hole. A joint body formed with the above, a cap nut that is screwed into the male threaded portion of the joint body, an inner circumferential surface having an inner diameter that is the same as or slightly larger than the outer diameter of the outer circumferential protective coating layer of the corrugated pipe, and the inner circumferential surface. has a protrusion that engages with the corrugated outer circumferential surface of the corrugated pipe at the end thereof,
It has a cylindrical shape or a tapered outer circumferential surface having an angle smaller than the taper angle of the tapered hole, and is fitted into the tapered hole of the joint body by screwing the cap nut, and is connected to the inner circumferential surface. This pipe joint is characterized by having a sleeve to which an outer surface protective coating layer is crimped.

[Effect]

Insert a cap nut into the corrugated pipe, and make about 1 to 5 corrugated peaks protrude from the end of the corrugated pipe. With the inner circumferential surface of the sleeve almost in contact with the outer protective coating layer of the corrugated pipe, the end of the sleeve should be When the sleeve is fitted and engaged with the outer circumferential surface of the corrugated pipe, and the corrugated pipe is attached, the sleeve is inserted into the tapered hole of the joint body and the cap nut is tightened.The sleeve moves to the back of the tapered hole and contracts in diameter. While tightening the outer surface of the corrugated pipe, the inner peripheral surface of the sleeve and the outer surface protective coating layer are crimped. Therefore, even when the cap nut is tightened and rotated, the corrugated pipe does not rotate together, and at the same time, the end of the corrugated pipe protruding from the sleeve is crimped with the pipe receiving wall, and thus the end of the corrugated pipe and the outer surface The protective coating layer is connected to the joint body with sealing properties.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention before the cap nut is tightened, and FIG. 2 is a sectional view showing the state after the cap nut is tightened.

In FIG. 1, reference numeral 1 denotes a joint body, which has a tapered pipe thread 5 carved on the outer periphery of one end to serve as a connection means to equipment, and has a communication hole 6 in the center. A tapered hole portion 7 with a smaller diameter on the back side is formed at the other end, and a tube receiving wall portion 8 that is continuous with the communication hole 6 is provided on the back side. The tube 4 is made of thin metal, has a corrugated outer peripheral surface, and is covered with a protective coating 10.

In addition, the sleeve 3 surrounding the protective sheathing part 10 of the tube 4 has a protrusion 32 formed on the inner side of the end on the insertion side into the joint body 1, which engages with the corrugated outer periphery of the tube 4 from which the protective sheathing part 10 has been removed. has been done. Note that the cross section of this protrusion 32 is square in the figure, but the cross section of the tube 4
It may be a semicircular shape that fits the groove shape of the protrusion 3.
2 may be slightly shifted inward from the end surface 31 (to the left in the figure). The rear part of the outer circumference of the sleeve 3 is provided with an open end 7 of the tapered hole 7 of the joint body 1 so that it can be easily engaged and pressed when tightening the cap nut 2.
A flange portion 11 that protrudes toward the outer periphery is provided so that the tightening margin of the cap nut 2 is regulated to a constant level when it abuts against the cap nut 1 (however, this flange portion 11 is not an essential requirement for the configuration of the present invention). . The outer circumferential surface 33 in front of the flange portion 11 forms an outer circumferential surface having a smaller angle than the tapered hole portion 7 of the joint body 1,
In this embodiment, the outer peripheral surface 33 of the sleeve 3 is formed in a parallel cylindrical shape with an angle of about 2 degrees on one side, while the tapered hole 7 of the joint body 1 has an angle of about 2 degrees on one side. However, the taper angle may be the same as the angle of the tapered hole portion 7 of the joint body 1.

Note that 12 is a step for hooking the sleeve 3 with a screwdriver or the like so that it can be easily removed from the joint body 1 when the cap nut 2 is tightened and connected and the pipe 4 is removed by loosening the cap nut 2 from the joint body 1 again. It is part 12 and has no bearing on sealing performance. The sleeve 3 may be divided into two parts in the axial direction as shown in FIG. 3, or the sleeve 3 may be opened by hand and attached to the pipe 4 with the cut groove 36 at one location.

In addition, a fire-resistant gasket 14 is attached to the pipe receiving wall 8, but if the pipe has a spiral waveform, this gasket 14 improves the adhesion between the pipe end 41 and the pipe receiving wall 8 to improve sealing performance. In order to maintain the pipe 4, the pipe end 41 and the pipe receiving wall 8 are in close contact with each other over the entire circumference in the case of a continuous annular pipe 4 in which each corrugation of the pipe 4 is formed individually. Therefore, it is not necessarily necessary to provide the gasket 14.

When connecting the pipes, first insert the cap nut 2 into the pipe 4, then insert the sleeve 3 into the pipe 4 so that the wave peaks are 1 to 5.
Attach it so that the peak protrudes and matches the wave peak of the tube 4. At this time, the end of the protective coating 10 of the tube 4 is inserted into the inner circumference 34 of the sleeve 3.

The sleeve 3 mounted on the pipe 4 in this manner is inserted into the tapered hole 7 as shown in FIG. 1, and the cap nut 2 is screwed into the parallel male threaded portion 9 of the joint body 1. From this state, when tightening the cap nut 2 to the joint body 1 side,
The sleeve 3 is reduced in diameter by the tapered hole 7 and advances toward the back of the tapered hole 7 while crimping the pipe protective coating 10, and the crimped protective coating 44 is compressed between the sleeve 3 and the inner circumferential surface 34 of the sleeve 3. is formed to prevent moisture from entering from outside.

Furthermore, if an O-ring groove is provided on the inner surface of the flange portion 11 of the sleeve 3 as shown in FIG. 4, and an O-ring 35 is attached thereto, the intrusion of moisture etc. from the outside can be more reliably prevented.

In addition, the front protruding pipe portion 4 with the sleeve 3 attached
2 advances at the same time as the sleeve 3, and its tip 41 hits the pipe receiving wall 8 of the joint body 1, and as the cap nut 2 is tightened, the protruding pipe 42 begins to be compressed, and the pipe receiving wall 8 and sleeve 3 and the front end portion 31 of the tube 3 to form a crimp tube portion 43 as shown in FIG. An internal fluid sealing action is performed between the crimp tube portion 43 and the tube receiving wall portion 8.

〔Effect of the invention〕

As described above, according to the present invention, the pipes can be easily connected by cutting them at the piping site, and since the protective covering of the pipes is enclosed within the joint body, it is possible to prevent leakage for a long time due to the corrosive environment from the outside. Concerns about performance are eliminated, and piping connections with a long life can be realized.

Furthermore, the angle of the tapered hole of the main body that comes into contact with the outer circumferential surface of the sleeve makes it easy to insert the sleeve into the tapered hole of the main body, and a crimped protective coating is formed to securely fix the tube and A stable connection can be obtained without deformation or scratches.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an embodiment of the present invention before the pipe connection is completed, FIG. 2 is a partial sectional view showing the state after the pipe connection is completed, and FIG. 3 is a partial sectional view of the sleeve shown in FIG. The side view and FIG. 4 are partial cross-sectional views showing another embodiment. 1: Joint body, 2: Cap nut, 3: Sleeve,
4: corrugated pipe, 7: tapered hole, 8: pipe receiving wall, 10: protective coating, 32: protrusion, 34: inner peripheral surface, 36: cut groove, 42: protruding pipe.

Claims (1)

[Scope of Claims] 1. A pipe joint for connecting thin-walled metal corrugated pipes having an outer surface protective coating layer, which has a male thread on the outer periphery of one end and a small angle threaded portion facing deep on the inner periphery. It has a tapered hole that is uniformly warped, and has a through hole with a smaller diameter than the tapered hole on the inner periphery of the other end,
A joint body having a pipe receiving wall formed at the boundary between the through hole and the tapered hole, a cap nut screwed into the external thread of the joint body, and an outer diameter of the outer surface protective coating layer of the corrugated pipe. It has an inner circumferential surface with the same or slightly larger inner diameter, and a protrusion that engages with the corrugated outer circumferential surface of the corrugated pipe at the end of the inner circumferential surface, and is cylindrical or has an angle smaller than the taper angle of the tapered hole. The sleeve has a tapered outer circumferential surface, is fitted into the tapered hole of the joint body by screwing the cap nut, and has a sleeve that presses the inner circumferential surface and the outer protective coating layer. pipe fittings. 2. The pipe joint according to claim 1, wherein the sleeve has at least one slit groove formed therein so that the diameter of at least the tip end can be expanded. 3. The pipe joint according to claim 1 or 2, wherein a contact member is interposed on the inner circumferential surface of the sleeve.