JPH084954A - Pipe joint - Google Patents

Abstract

PURPOSE:To provide a pipe joint where the piping work is rapid, easy and sure, and the universal applicability to the pipe size is provided to eliminate the troubles in controlling the material. CONSTITUTION:A pipe joint consists of a sealing sleeve 2 to be fitted to an abutting end part of tubes 5, 6, and a coil-shaped tightening tool 3 which can be externally fitted to this sleeve 2. The tightening tool 3 is formed of the wire made of the shape memory alloy, and the diameter of the coil is reduced by heating it at the normal temperature to tighten the sleeve 2 from the whole circumference in a water tight manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint used for connecting pipes such as drainage pipes.

[0002]

2. Description of the Related Art In a pipe joint structure, male screws are engraved on the ends of the pipes on the abutting side, and these are screwed into a socket with a female thread to connect them. A flange joint is fixed on the abutting ends of the pipes. Incidentally, a method of fastening these with bolts and nuts, or a pipe joint 12 capable of expanding and contracting the inner diameter by providing fastening portions 11 with bolts and nuts 10 at several locations in the circumferential direction as shown in FIG. Tube 1
There is a method in which a crotch is provided between the abutting end portions of the Nos. 3 and 14 and tightened via a sealing material.

[0003]

In the socket connection system, a screw must be formed at the end of the pipe, and at the time of pipe connection, the socket or the pipe itself must be screwed and rotated, which is troublesome for piping work. Is. In addition, in the flange joint method, not only the flange protrudes in the radial direction, but also an extra space must be secured around the pipe for bolt and nut fastening work, which is restricted in place and bolt fastening is required. Therefore, the piping work was inefficient.

On the other hand, in the system shown in FIG. 3, it is not necessary to rotate the pipe by screwing, and the fastening work of the bolts and nuts 10 is reduced, but the screwing work is still required, so the piping work is troublesome. Met. Also the pipe joint 12
It is necessary to prepare a large number of different types according to the pipe diameter and it is not versatile, so it was necessary to prepare many types.

The present invention has been made in view of the above circumstances, and enables the piping work to be performed quickly, easily and surely, and has a versatility with respect to the pipe diameter to eliminate the complexity of material management. An object of the present invention is to provide a pipe joint having the above structure.

[0006]

DISCLOSURE OF THE INVENTION A pipe joint of the present invention has a sealing sleeve which is crotch-fitted between butt ends of pipes, and a coil shape which can be externally fitted to the sleeve. A fastening tool made of a shape memory alloy, which returns to a memorized reduced-diameter shape by heating at a temperature not lower than the transformation temperature. The sleeve may be formed by winding a water resistant strip.

[0007]

The sleeve and the fastener are fitted onto one of the pipes, and the pipes are brought into a butted state with each other, and the sleeve is moved so that the butted ends of the pipes are crotched.
Next, the above-mentioned tightening tool is moved so as to be fitted onto the sleeve, and is heated so as to return to the memorized reduced diameter shape.

By doing so, the tightening tool causes a shape recovery action and returns to the diameter-reduced shape stored in advance, so that the sleeve is tightened from the entire circumference to the circumference of the tube, and both tubes are water-tight. To be held bonded.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 (a) shows a disassembled state of a pipe joint 1 according to the present invention, and FIG. 1 (b) shows the same joint state. The pipe joint 1 includes a sleeve 2 and a fastener 3. It will be done.

The sleeve 2 is made of a rubber material such as SBR or EPR and has a cylindrical shape. The inner diameter of the sleeve 2 is equal to or slightly larger than the outer diameter of the tubes 5 and 6. It should be noted that, depending on the hardness and thickness of the raw material rubber or the smoothness of the inner peripheral surface, if the outer fitting of the pipes 5 and 6 can be easily performed, the outer diameter of the pipes 5 and 6 may be made smaller. Good.

The fastener 3 is formed by winding a shape-memory alloy wire into a coil. In this example, a unidirectional Ni—Ti alloy or the like was used as the shape memory alloy. In the pre-use stage (storage stage), this tightening tool 3 has a coil inner diameter of at least the outer diameter of the sleeve 2 (tube 5 at room temperature to the lowest temperature in cold regions).
Or, it is formed so as to have a smaller diameter than that after being externally fitted to 6), and this state is stored as a reduced diameter shape.
The diameter to be stored is usually set so that the smallest diameter of the pipes having various pipe diameters, which are connected by the tightening tool 3, can be tightened.

Prior to its use, this tightening tool 3 is cooled to about several tens of degrees Celsius below zero, which is equal to or lower than the phase transformation temperature, so that the inner diameter of the coil is at least the outer diameter of the sleeve 2 (tube 5 or 6).
The outer diameter is larger than that after external fitting). When the fastener 3 is placed in the outer peripheral portion in this state and the fastening tool 3 is heated to room temperature or higher, a shape recovery action occurs and the stored reduced diameter shape is restored. The inner diameter of the coil that expands at low temperature is usually set so that the largest diameter tube among the tubes having various tube diameters that are connected by the fastener 3 can be inserted.

The fastener 3 can be cooled to the phase transformation temperature by blowing a cooling gas such as liquid nitrogen onto the fastener 3. After expanding the diameter in this cooling state, the fastening tool 3 may be put in an appropriate cooling case or the like to be maintained at a low temperature and transported to the piping site. The piping work is performed as follows using the pipe joint 1 according to the embodiment.

That is, the sleeve 2 and the tightening tool 3 in a cooled state are externally fitted to one of the pipes 5 or 6 to make the pipes 5 and 6 abutting each other, and the sleeve 2 is moved to move the abutting end portions between these abutting ends. Try to make your crotch. Next, the fastener 3 is moved and placed on the outer peripheral portion of the sleeve 2.
Then, the fastener 3 is heated to room temperature by applying hot water or warm air. As a result, the tightening tool 3 causes a shape recovery action and tries to return to the reduced diameter shape stored in advance, so that the tightening tool 3 tightens the sleeve 2 from the entire circumference thereof (see FIG. 2), and both tubes 5, 5. The pipes 5 and 6 are tightly fitted to each other in a watertight manner, and the pipes 5 and 6 are held in a tight fitting state in which they cannot escape.

In the present invention, if the shape memory alloy used for the fastener 3 is a shape memory alloy which exhibits a stable (shape memory) state at the lowest temperature in normal temperature to cold regions, the above Ni is used.
Of course, a material other than the -Ti alloy can also be used. The sleeve 2 may be formed of a soft resin, a relatively soft metal such as aluminum, copper, lead, tin, or an alloy thereof. Further, the sleeve 2 is not limited to externally fitting a tubular shape from the beginning to the pipes 5 and 6, and for example, a waterproof belt-shaped material such as rubber, resin, or a covering cloth made of rubber is abutted on the pipes 5 and 6. It can also be configured by crotch between the end portions and densely winding (coating attachment). In this case, the sleeve can be easily formed regardless of the pipe diameter.

[0016]

According to the present invention, which has the above-described structure, a coil-like tightening tool made of a shape memory alloy is attached to a sleeve which is covered and attached so as to be crotch between the abutting ends of the tubes. Since the fitting work is done and the piping work is performed by heating and reducing the diameter of this fastening tool, the fastening work of the bolts and nuts is completely unnecessary, and the work can be made faster (higher efficiency) and easier. Can be achieved. Moreover, since it does not require a large space for work, piping can be performed even in a narrow space. Moreover, since the tightening tool is versatile with respect to the pipe diameter, the number of kinds of the tightening tool can be reduced, and the manufacturing cost can be reduced and the material management can be facilitated. Further, if the sleeve is formed by winding a water resistant strip, the sleeve also has excellent versatility with respect to the pipe diameter, and material management becomes easy.

[Brief description of drawings]

FIG. 1 shows a pipe joint according to the present invention, in which (a) is a disassembled state and (b) is a joined state.

FIG. 2 is an enlarged cross-sectional view of part A in FIG.

FIG. 3 is a side view showing an example of a conventional pipe joint structure.

[Explanation of symbols]

 1 Pipe joint 2 Sleeve 3 Fastener

Claims (2)

[Claims] 1. A sealing sleeve (2) crotch-fitted between the abutting ends of the tubes (5, 6), and a coil shape which can be externally fitted to the sleeve (2). A pipe joint comprising a shape memory alloy tightening tool (3) that returns to a memorized reduced-diameter shape by heating at a transformation temperature or higher. 2. The pipe joint according to claim 1, wherein the sealing sleeve (2) is formed by winding a water resistant strip.