JPS5949472B2 - Construction method for piping joints - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of constructing a joint portion of a ductile cast iron pipe for water supply buried underground.

For joints such as water pipes installed underground, normally, as shown in FIG. A styrene-based synthetic rubber ring 3 is fitted onto the connected pipe 2 and pushed halfway into the expanded diameter part of the connecting pipe 1.Furthermore, a metal press ring 4 is secured to the connecting pipe 1 using a T-shaped bolt 5 and a nut 6. By tightening the flange 7, its annular suppressing surface 4' presses the rubber ring 3, and the rubber ring 3 presses against the inner surface of the enlarged diameter part of the connecting pipe 1 and the connected pipe 2.
It is designed to fit closely to the circumferential surface of the pipe wall and act as a gasket.

However, this joint part is affected by road load or vibration due to earth pressure or increased traffic volume, and the connected pipe 1
．． 2 may become eccentric, and in this case, the rubber ring 3 is also compressed on one side and loosened on the opposite side, making it impossible to perform a reliable sealing action.Also, due to aging of the rubber ring, water leakage may occur. This will occur.

In this case, the conventional method for replacing the rubber ring 3 is to remove the T-bolt 5 and nut 6, move the push ring 4, cut the rubber ring 3, and take it out. is set accurately, a new rubber ring 3 is wound around it, its cut end surface is glued, and as described above, the pressure ring 4 is manually pushed into the expanded diameter part of the connecting pipe 1 and tightened again.

However, since the coefficient of friction of the rubber ring 3 is extremely large, if it is wrapped too tightly around the pipe to be connected 2, it will be difficult to force the rubber ring to move due to the internal force of the enlarged diameter part of the connecting pipe, and if it is wrapped too loosely, it will often become damaged. In addition to being in a state of being deviated from the axis of the connecting pipe 2, there was a risk that even if it was pressed and fixed with the press ring 4, a complete closing effect would not be produced.

The present invention aims to eliminate the drawbacks of the conventional construction method described above, and aims to bond both ends of a rubber band whose length matches the outer periphery of the pipe to be connected to the bonded end surface with at least one side along the longitudinal direction. a step of forcibly stretching the rubber band wrapped around the removed connecting pipe and gluing the bonded end surfaces at both ends to form a rubber ring;
The gist is a step of evenly press-fitting the rubber ring that is in close contact with the pipe to be connected into the enlarged diameter portion of the connecting pipe.

The construction method of the present invention is to align the rubber band with the outer circumference of the pipe to be connected,
Both ends are fixed to a crimping device and forcedly stretched, and the adhesive end surfaces provided at both ends are bonded to form a rubber ring.
The rubber ring, which has been elastically contracted by releasing the forced distraction, adheres to the circumferential surface of the tube with an optimal degree of adhesion without being too strong or too loose.

In addition, since this rubber ring is evenly compressed and moved into the enlarged diameter part of the connecting pipe by the crimping device through the press ring, the pushing operation is facilitated, and the rubber ring is prevented from being deviated from the axis of the pipe during movement. Therefore, the possibility of impairing the occlusion effect is completely eliminated.

Furthermore, even if a rubber ring that is in close contact with the circumferential surface of a pipe is moved under strong pressure, at least one side of the rubber ring's bonded end surface should be formed as a bonded end surface along the longitudinal direction, so that the bonded area is as large as possible, and the bonded end surface of the rubber ring is moved as much as possible. Since it is designed to increase the strength in the direction, the adhesive surface is strong and does not peel off easily.

Embodiments of the present invention will be described below with reference to the drawings.

In this construction method, as in the conventional method, the old rubber ring 3 is removed and a new rubber ring 3 is wrapped around the pipe 2 to be connected.

That is, first, attach the rubber band 3 to the outer circumference of the connected pipe 2.
1, and as shown in FIG. 3, its both ends are placed on a cutting table 8, fixed with a fixture 10 having a cutter guide groove 9, and cut with a cutter.

The shape of this cut surface a may be flat as in the conventional case, but in order to increase the bonding area and strengthen the strength in the transverse direction, it should be shaped as shown in FIG. 4. Next, this rubber band 3' is wrapped around the pipe to be connected 2, and as shown in FIGS. .13, and operate this crimper 11 to tighten the rubber band 3.
' is stretched, and the cut end surfaces of both ends are brought together and glued together to form a rubber ring 3.

After the adhesive dries and hardens and is completely bonded, when both ends are removed from the arm 12, 13, the rubber ring 3 contracts due to its elasticity and tightly adheres to the circumferential surface of the pipe wall of the pipe to be connected 2.

Thereafter, as shown in FIG. 7, the annular pressing surface 4' of the pressing ring 4 inserted into the pipe to be connected 2 is brought into contact with the rubber ring 3, and the pressing ring 4 and the flange 7 of the connecting pipe 1 are brought into contact with each other. Apply strong pressure with the arms 12 and 13 of the crimper 11 to force the rubber ring 3 into the internal force of the enlarged diameter part of the connecting tube 1.

In this case, the push ring 4 is set so that at least two parts are pressed so that the rubber ring 3 is evenly pressed and moved without being biased against the axis of the connected pipe 2 (see Fig. 8). .

Once the rubber ring 3 is pushed into the enlarged diameter portion, the crimping device 11 is removed and the bolt 5 and nut 6 are tightened to fix the push ring 4 in the same manner as in the prior art.

In this embodiment, the crimping device 11 is operated by a hydraulic pump, but the present invention is not limited to this, and the crimping device 11 may be operated by, for example, a ratchet mechanism.

As described above, according to the present invention, the rubber ring wrapped around the circumferential surface of the pipe to be connected has an optimal degree of adhesion and has sufficient resistance to strong pressure movement by a crimper. Since it is press-fitted evenly by the crimping device, deviation with respect to the axis during movement can be prevented, a reliable closing effect can be produced, and the pressing operation can be smoothed and simplified.

[Brief explanation of drawings]

Figure 1 is a partial longitudinal sectional view of the pipe joint, Figure 2
The figures show a specific example of this construction method, Fig. 2 is a slope view of the rubber ring, Fig. 3 is a plan view of the cutting process of the end of the rubber band, Fig. 4 is a diagram of the shape of the cut surface, and Fig. 5 The figure is a cross-sectional view of the adhesion process, No. 6
The figure is a plan view of the same process, Figure 7 is a sectional view of the pushing process, and Figure 8 is a cross-sectional view of the pushing process.
The figure is a side view of the press ring side in the same process. 1... Connecting pipe 1. 2... - Connected pipe, 3... Rubber ring, 3'... Rubber band.

Claims (1)

[Claims] 1 The process of cutting both ends of a rubber band with a length that matches the outer circumference of the pipe to be connected into a bonded end face that can be butted with at least one side along the longitudinal direction, and wrapping it around the pipe to be connected. A step of forcibly stretching the attached rubber band and bonding the bonded end surfaces at both ends to form a rubber ring, and evenly press-fitting the rubber ring that is in close contact with the pipe to be connected into the enlarged diameter part of the connecting pipe. A construction method for piping joints consisting of processes.