JPH0888918A - Tube joint - Google Patents

Abstract

PURPOSE: To prevent the invasion of water, etc., from the exterior of a tube joint into a conduit tube by disposing a protective piece so as to be disposed in a gap between flanges on the outer periphery of a packing, thereby sealing the packing with the inner periphery of a housing and the outer periphery of the tube. CONSTITUTION: A protective piece 4 and a packing 3 are mounted in the recess 24 of a housing 2. The end of the tube is inserted from a clamping part 23 side into the housing 2, and so disposed that the end is brought into contact with the stepped parts of a large-diameter cylindrical part 22 and a small- diameter cylindrical part 21. The bolt 8 of the part 23 is clamped to draw flanges 25a, 26a to each other to reduce the gap therebetween, and clamping pieces 25, 26 are radially inwardly displaced. A protruding stripe 28 provided on the inner periphery of the part 23 is intruded to the periphery of the tube to fix it. Simultaneously, the inner peripheries of the pieces 25, 26 press the outer periphery of the packing 3 via the piece 4 to compress the packing 3, thereby watertightly sealing the joint to the tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof type pipe joint for connecting a pipe body such as a conduit to a device such as a control box, and more particularly, a waterproof type pipe joint suitably used as a joint for thick steel conduit pipes. Regarding pipe fittings.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventionally known pipe joint of this type. In FIG. 4, a pipe joint 100 is a hollow cylindrical joint body 101 and a tightening nut 1 screwed with the joint body 101.
Have 02. The joint body 101 has a step 103 on its inner circumference.
The thick steel conduit 103 to be connected has a tightening nut 1
It is inserted from the No. 02 side, and its pipe end is placed in contact with the step portion 103 of the joint body 101. One or an appropriate number of tightening screws 104 are provided on the peripheral wall of the joint body 101 so as to penetrate the wall and project the ends into the hollow portion. The ends of the screws 104 tighten the outer circumference of the electric conduit 103. Thus, the conduit 103 can be fixed to the joint body 101. After this fixing, the tightening nut 102 is tightened to compress the waterproof packing 105 arranged inside to waterproof the gap between the tightening nut 102 and the joint body 101 and the conduit 103. Reference numeral 106 denotes a grounding screw, and the tip of the screw is in contact with the electric wire tube 103 to enable the electric wire tube to be electrically grounded.

As described above, in the conventional structure, (1)
Tightening the screw 104, (2) Tightening the tightening nut 102,
The connection work consists of two steps. In addition, when a plurality of rows of thick steel conduits are piped, a working space for turning the tightening nut 102 is required for each pipe, so that there is a problem that the piping space must be wide. There is.

[0004]

In view of this, the applicant of the present invention has a hollow cylindrical joint body that is fastened (reduced in diameter) to one end of a hollow cylindrical joint body as a pipe joint that solves the above-mentioned problems of the prior art.
A pair of possible fastening pieces are provided, and the fastening pieces are displaced inward in the radial direction by tightening bolts between the flanges that project outward in the radial direction at the ends of these fastening pieces, so that the electric wire in the joint is The tube is pressed and fixed by the inner circumference of the tightening piece, and at the same time, the elastic packing that surrounds the circumference of the conduit is compressed, so that the packing is pressed against the peripheral surface of the conduit and adheres tightly to waterproof the conduit to the joint. Proposed a configuration to connect.

In such a structure, the connection may be performed by one operation of simply tightening the flanges with bolts, which is a great advantage that the connecting work is very simple as compared with the above-mentioned conventional structure. Have. However, on the other hand, the elastic packing part bulges due to the gap between the flanges that gradually narrows due to bolt tightening, and water leaks from the gap between the conduit and packing formed in this bulge. Also, there is a possibility that the packing itself may be damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pipe joint having a good workability and having a simple structure, which solves the above-mentioned problems.

[0007]

For this reason, the pipe joint according to the present invention has a pair of tightening members which receive the ends of the pipes to be connected therein and which can be tightened radially inward toward the insertion port side of the pipes. A housing having a piece, and an elastic packing fitted in a recess on the inner circumference of the housing and closely contacting the peripheral surface of the end portion of the pipe to be connected, and each of the tightening pieces projects outward in the radial direction at the end portion. A fitting having a flange and facing each other with a gap, and tightening the fastening piece by tightening a bolt between the flanges to tightly attach the packing to the outer circumference of the pipe. A protective piece is arranged on the outer periphery of the protective member so as to be located at least in the gap between the flanges. And especially,
The protective piece is made of a thin arc-shaped metal strip.

[0008]

In this means, when the flange of the tightening piece is tightened with the bolt, the tightening piece is radially inwardly contracted and displaced, and the conduit to be connected is firmly fixed at the inner periphery thereof. The packing inside the housing is pressed to deform it, and the packing is brought into close contact with the inner circumference of the housing and the outer circumference of the electric wire tube to prevent water and the like from entering the electric wire tube from outside the joint. At this time, the protective piece arranged on the outer periphery of the packing acts so as to press the packing from the outer peripheral side, that is, to prevent a part of the packing from expanding into the gap between the flanges as described above. .

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show a typical structure of a pipe joint 1 according to the present invention. The pipe joint 1 is a metal housing 2, an elastic packing 3 made of a cylindrical rubber material or the like mounted in the housing 2, and an arc-shaped thin thickness used so as to cover a part of the outer periphery of the packing 3. And a protection piece 4 made of a metal strip. As the protective piece 4, for example, a stainless steel plate having a thickness of 0.1 to 0.3 mm can be used. In the figure, in addition to this, the seat packing 5, the lock nut 6, and the insulator 7 are further shown.

The housing 2 has a hollow, generally cylindrical shape as a whole, and has a small diameter cylindrical portion 2 along its axial direction.
1. The large-diameter cylindrical portion 22 and the tightening portion 23 are integrally formed and provided. A screw for fixing the housing 2 to a frame of a device such as a control box is formed on the outer periphery of the small-diameter cylindrical portion 21, and an annular seat packing 5 is provided in an annular recess formed at the base thereof. It is installed so that it is in close contact with the frame and waterproof when it is connected to the frame. The small-diameter cylindrical portion 21 penetrates through a mounting hole formed in the frame body of the device to be fixed and projects and is attached to the back side of the frame body. From the back side of the frame body, the lock nut 6 is screwed and tightened. It is fixed to the frame by. In addition, a cylindrical insulator 7 having an annular flange portion that projects outward in the radial direction is attached to the end of the small-diameter cylindrical portion 21 so as to fit into the inner circumference of the small-diameter cylindrical portion 21. The insulator 7 has electrical insulation properties, and the flange portion covers the edge of the small-diameter cylindrical portion 21, and the exposed portion of the wire or cable inserted through the housing 2 comes into contact with the edge of the small-diameter cylindrical portion to cause electric leakage. Prevent it from occurring.

A wide concave portion 24 is formed in an annular shape on the inner peripheral surface of the large-diameter cylindrical portion 22 of the housing, and a wide cylindrical elastic packing 3 is detachably fitted and supported in the concave portion 24. It The thickness of the packing 3 is formed to be slightly thicker than the depth of the recess 24. The packing 3 has an inner diameter slightly larger than the outer diameter of the pipe so that the connecting pipe can be easily inserted, and the outer diameter is formed to be slightly larger than the diameter of the bottom surface of the recess 24. There is. Due to this difference in diameter, when the tightening portion 23 is tightened, the packing 3
Is pressed inward to be deformed, and as a result, the packing 3 is tightly adhered to the inner circumference of the housing and the outer circumference of the tube without any clearance, thereby waterproofing. The packing 3 has substantially the same width as the recess 24, and a plurality of annular grooves or ridges 31 are formed on the inner peripheral surface of the packing 3 so as to make good contact with the pipe. .

In the untightened state, the tightening portion 23 of the housing 2 has an inner peripheral surface having a diameter slightly larger than the outer diameter of the pipe to be connected, and a part of its circumference (about half circumference). A pair of tightening pieces 25, 2 with one end released so that the outer diameter of the pipe to be connected can be tightened by reducing the diameter inward in the radial direction.
It is composed of six. The fastening pieces 25, 26 are arc-shaped pieces formed by forming slits 27 along the circumferential direction in the recess 24 of the large-diameter cylindrical portion 22 of the housing. The free end is formed with flanges 25a, 26a protruding outward in the radial direction. The flanges 25a and 26a have a gap 27 between them.
Are substantially parallel to each other and face each other in parallel with each other, and by tightening (pulling) between them, the tightening pieces 25 and 26 are radially inwardly reduced, that is, tightened. The inside of the tightening portion 23 (including the tightening pieces 25 and 26) is for cutting into and fixing the peripheral surface of the pipe to be connected,
It has a ridge 28 having a wedge-shaped cross section with a relatively sharp tip. In the illustrated example, the ridge 28 is formed continuously along the circumferential direction, but it may be formed in a discontinuous arc or spot shape. These ridges 28 do not hinder the insertion of the pipe to be connected into the housing 2,
Further, when the tightening pieces 25 and 26 are tightened, they have sufficient height and strength to bite into the tube and fix it.

To connect a thick steel conduit tube to such a joint, first, the protective piece 4 and the packing 3 are mounted in the recess 24 in the housing 2. Next, the end portion of the conduit is inserted into the housing 2 from the side of the tightening portion 23, the packing 3 is inserted, and the end portion is brought into contact with the step portion of the large diameter cylindrical portion 22 and the small diameter cylindrical portion 21. Position it. Next, the bolt 8 of the tightening portion 23 is tightened to draw the flanges 25a and 26a toward each other to close the gap therebetween, and the tightening pieces 25 and 26 are displaced inward in the radial direction. By such tightening, the ridge 28 provided on the inner circumference of the tightening portion 23 bites into the peripheral surface of the electric wire tube and fixes it. At the same time, the inner peripheral surfaces of the tightening pieces 25 and 26 press the outer circumference of the packing 3 via the protective piece 4 and press the packing 3 together.
To seal the joint and pipe connection in a watertight manner.
At this time, as shown in FIG.
A small gap remains between 5a and 26a.

FIG. 3A shows a structure having a protective piece 3 according to the present invention. In the above-mentioned gap between the flanges, the protective piece 4 is deformed so as to bend under the pressure of the tightening pieces 25 and 26, and accordingly, the packing 3 located inside the protective piece 3 is extremely deformed. That is, it is possible to prevent a deformation that hinders close contact / waterproofing with the pipe to be connected. FIG.
For comparison with the present invention, (b) illustrates a case where the protective piece 4 is not provided, but the packing 3 is the flange 2 described above.
It is deformed by being extremely tightened between 5a and 26a and forms a gap with the pipe to be connected to impede the waterproofing power.
The protective piece 4 also has a function of protecting the packing 3 from the intrusion of foreign matter such as earth and sand through the gap between the flanges.

[0015]

As described above, according to the present invention, when the bolts are tightened, the flanges of the joint body are attracted to each other, the inner rubber packing is compressed, and the protrusions on the inner circumference of the joint housing bite into the conduit. Fix it firmly. As described above, since the connection can be performed only by tightening the bolts, the work space can be minimized, and the connection work can be performed in a short time. Furthermore, by adopting a configuration in which the protective piece is arranged around the elastic packing, damage to the packing or water leakage between the flanges can be prevented.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an example of a pipe joint according to the present invention.

FIG. 2 is a view showing an assembled state of the pipe joint shown in FIG.

3A is an enlarged view of a mounting portion of a pipe joint according to the present invention, and FIG. 3B is a mounting view of a part of a conventional pipe joint.

FIG. 4 is a view showing an example of a conventional pipe joint.

[Explanation of symbols]

 1 Pipe Joint 2 Housing 3 Packing 4 Protective Piece 8 Bolt 21 Small Diameter Cylindrical Part 22 Large Diameter Cylindrical Part 23 Tightening Part 24 Recess

Claims (2)

[Claims] 1. A housing which receives an end of a pipe to be connected therein and which has a pair of tightening pieces which can be tightened radially inward on an insertion opening side of the pipe, and is fitted in a concave portion of an inner circumference of the housing. , An elastic packing that closely adheres to the peripheral surface of the end of the pipe to be connected, each of the fastening pieces has a flange protruding outward in the radial direction at the end, and the flanges face each other with a gap. A pipe joint that is positioned to tighten the fastening piece by tightening a bolt between the flanges to bring the packing into close contact with the outer circumference of the pipe, and to be located at least in the gap between the flanges on the outer circumference of the packing. A pipe joint characterized by having a protective piece. 2. The pipe joint according to claim 1, wherein the protection piece is made of an arcuate thin metal strip.