JPH0579585A - Fluid coupling - Google Patents

Abstract

PURPOSE:To prevent the loosening of a fluid coupling due to vibration and thermal cycle. CONSTITUTION:A fluid coupling is equipped with a union nut 8 which allows two pipes 1a and 1b to be inserted each other and tightens them by a screw part, tighetening fitting 5 which is inserted in free revolution into the pipe 1a, and a spring 2 installed at the hooks 3 and 4 of the tightening fitting 5 and the pipe 1a. The union nut 8 is applied with a revolution torque due to the restoring force of the spring 2 in the revolution direction same to the tightening direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid coupling in piping for flowing a fluid, and more particularly to a fluid coupling having a tightening structure.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of a conventional fluid coupling. Conventionally, this type of fluid coupling is, for example, as shown in FIG. 2, an inner ferule 10 which is watertight between the fitting pipes 1a and 1b, and which is inserted into the pipe 1b and is screwed into a male screw of the pipe 1a. And a union nut 8 on which a female screw is formed.

When connecting two pipes with this fluid coupling, first, the pipe 1b having the inner ferule 10 is inserted into the pipe 1a. Next, the union nut 8 inserted in the outer periphery of the pipe 1b was fitted into the male screw of the pipe 1a and tightened to water-tightly connect the pipe 1a and the pipe 1b.

[0004]

In the above-mentioned conventional liquid joint, since the tightening force is only the engagement of the male thread of the pipe and the female thread of the union nut, it has no means for maintaining the tightening. The union nut is often loosened due to heat cycles and vibrations, resulting in liquid leakage. There is a problem that it is dangerous in the case of a particularly harmful liquid.

An object of the present invention is to provide a fluid coupling in which tightening is not loosened by heat cycle or vibration in order to solve such a problem.

[0006]

The fluid coupling of the present invention has two components.
A fastener having two pipes inserted into each other through a seal member and fitted into a threaded portion of one of the pipes for tightening, and a fitting that rotatably fits into the pipe and holds the union nut at one end. And a spring that applies a rotational force to the tightening tool in the same direction as the tightening direction of the union nut.

[0007]

The present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view showing a liquid joint according to an embodiment of the present invention. As shown in FIG. 1, this fluid coupling includes a tightening tool 5 which is rotatably fitted around the pipe 1a and has a projection 6 which is inserted into a recess 7 of a union nut 8 on one end side, and Hook 4 at the other end of tool 5
1 is attached and the other end is attached to the hook 3 of the pipe 1a. That is, the tightening tool 5 applies a constant rotational torque to the union nut 8 by the restoring force of the spring 2 to prevent the union nut 8 from loosening.

Next, a method of mounting the fluid coupling will be described. First, the pipe 1b is inserted into the pipe 1a, and the union nut 8 is fastened to the pipe 1a. Next, in this state, the tightening tool 5 is rotated against the spring 2 in the direction opposite to the tightening rotation direction of the union nut 8,
The protrusion 6 is pushed into the recess 7 of the union nut 8 and fixed. As a result, the tightening torque is constantly applied to the union nut 8 by the restoring force of the spring 2, and the loosening can be prevented.

Here, a similar effect can be obtained by using a rotary actuator instead of the spring 2 as a means for generating the tightening torque. However, not only that, but also when the union nut 8 rotates. A constant tightening torque can be applied and maintained.

[0010]

As described above, according to the present invention, the union nut for tightening the pipes is provided with the tightening tool for applying the rotating torque by the restoring force of the spring in the tightening rotating direction, so that the union nut can be tightened at a constant tightening torque. Since it is always applied, there is an effect that a fluid coupling that does not loosen due to vibration or heat cycle can be obtained.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a fluid coupling of the present invention.

FIG. 2 is a partial cross-sectional view showing an example of a conventional fluid coupling.

[Explanation of symbols]

 1a, 1b Piping 2 Spring 3,4 Hook 5 Tightening tool 6 Protrusion 7 Recess 8 Union nut

Claims (1)

[Claims] 1. A union nut that fits and tightens two pipes into a threaded portion of one of the pipes while they are inserted into each other via a sealing material, and a union nut rotatably fitted in the pipe and holding the union nut at one end. A fluid coupling, comprising: a fastener having a means for controlling the tension; and a spring that applies a rotational force to the fastener in the same direction as the tightening direction of the union nut.