JPH02159490A - Pipe joint - Google Patents

Abstract

PURPOSE:To improve sealing quality by providing a metal circular body externally coupled to a tube, and a locknut for screwing into a joint body and pressing the open end of the tube to the truncated conical end of the joint body. CONSTITUTION:The pipe joint in the title comprises a metal circular body 11 and a locknut 13. The metal circular body 11 is coupled to the external surface of a flexible tube 12 near the end thereof, and the open end of the tube 12 is thereby flared. The locknut 13 is screwed into the male thread of a joint body 14 at one end and the other end of the nut 13 is used as a flanged tube insertion part 13a. The locknut 13 presses the circular body 11 of the tube 12 with the insertion part 13a, thereby pressing the open end of the tube 12 for contact with the truncated conical end of the joint body 14. According to the aforesaid construction, a pipe joint becomes free from a liquid pocket and enables easy assembly. Also, sealing quality and drawing strength becomes excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides a method for connecting flexible tubes, such as plastic tubes, rubber hoses, etc., with less liquid accumulation, good sealing performance, and easy removal of tubes. This invention relates to a simple pipe joint with an enhanced stopping force.

[Conventional technology]

Traditionally, there have been a wide variety of pipe fittings depending on their purpose, but
For example, there is a pipe joint as shown in FIG. 4, in which the pipe to be connected is a flexible plastic tube and the joint body is made of a fluororesin such as PFA.

In the figure, 1 is a joint body made of resin, and 2 is an insert portion into which a plastic tube 3 is fitted. Reference numeral 4 denotes a sleeve which is a thin metal cylinder, through which the plastic tube 3 is inserted in advance, and after the tube 3 is inserted into the insert portion 2, it is brought to the position shown in FIG. 4(a). Next, using a crimping machine (not shown), the sleeve 4 is pressurized from the outside in the axial direction (this is called crimping) as shown in FIG. . At this time, a part of the wall thickness of the tube 3 falls into the annular groove 2a provided in the insert portion 2, so that the tube 3 has a resistance force in the pulling direction.

[Problem to be solved by the invention]

However, in the above-mentioned pipe joint, since both the joint body and the tube are made of resin, the frictional force at the contact portion is small. Therefore, in addition to providing an annular groove, it is necessary to make the insert part long in order to make the contact area sufficiently large. In addition, since the joint body is made of resin, there is a limit to the pressure force that can be applied to the sleeve due to its strength.Therefore, in order to completely maintain the pull-out prevention force and sealing performance, various measures in addition to those shown in the drawings must be taken. However, all of these problems have an impact on productivity, costs, etc. Furthermore, due to the presence of the insert portion, a step is created between the insert portion and the inner circumferential surface of the tube, resulting in the problem that liquid pooling is unavoidable.

This invention was made in view of such conventional problems, and by using an annular body that is easy to put on,
The purpose is to solve the above problems.

[Means to solve the problem]

The present invention includes a metal annular body that is fitted around the end of a flexible tube to reduce its diameter and make the open end of the tube flare, and a male thread of a joint body through which the tube is inserted. and a tightening nut that is screwed into the tube insertion portion and presses the annular body toward the joint body at the tube insertion portion, thereby bringing the tube opening end into pressure contact with the truncated conical end of the joint body. It is.

[Function] Since the present invention has the above-described configuration, the open end of the tube deformed into a flared shape is in a state where the truncated conical end of the joint body can be easily inserted. When the tightening nut is tightened to the joint body in this state, the tube insertion portion of the tightening nut presses the annular body toward the joint body as the tightening nut is tightened, so that the open end of the tube is brought into pressure contact with the end of the joint body. This ensures good sealing performance at the press-contact portion and completely prevents the tube from being pulled out, and the level difference on the inner circumferential surface side becomes extremely small.

〔Example〕

The present invention will be explained below based on the drawings. FIG. 1 is a diagram showing a first embodiment according to the present invention.

In the figure, reference numeral 11 denotes a sleeve as a metal annular body that is fitted onto the tube 12 and is crimped to reduce the diameter of the crimped portion of the tube 12. However, the tightening force should not be applied to the open end 12a of the tube 12.
Sleeve 11 at a position slightly apart from open end 12
is tightened. As a result, the tube opening end 12a becomes flared outward (see FIG. 3(a)).
reference).

In this embodiment, reference numeral 13 is a tightening nut made of resin, one end of which is screwed into a male threaded portion of a joint body 14 made of resin, and the other end forming a flange-like tube insertion portion 13a. The periphery of the insertion hole of this tube insertion portion forms a thick flange portion, which has enough strength to press the end portion of the sleeve 11 with sufficient force on its inner surface. Further, the joint main body end 14a is formed into an inclined surface (truncated conical shape), and has a shape that allows it to easily enter the diameter-enlarged tube opening end 12a (see FIG. 3B).

Now, the tightening nut 13 is inserted into the tube 12 in advance, and the sleeve 11 is attached as shown in FIG. 1(a). Next, connect the tube opening end 12a to the end 1 of the joint body 14.
4a, and then screw the tightening nut 13 onto the joint body 14. As the screwing progresses, the tube insertion portion 13a of the tightening nut 13 presses the sleeve 11 toward the joint body, so that the tube opening end 12a
is pressed against the joint body end 14a. In this way, the tube 12 is connected to the joint body 14, and the open end 12a is pressed against the tube 12, thereby maintaining good sealing performance and retaining force. Furthermore, since there is no insert part unlike in the conventional case, there is only a slight step in the flow path, and the occurrence of liquid pools is almost eliminated.

FIG. 2 is a diagram showing a second embodiment.

This is an example in which a metal ring 21 is used as the annular body, and by tightening the end portion of the tube 12 with this metal ring 21, the tube opening end 12a is slightly expanded outward as in the above embodiment. (See Figure 2(a)). When this is assembled to the joint body 14 in the same manner as above,
The tube insertion portion 23a of the tightening screw 23 presses against the metal ring 21, and the tube opening end 12a is brought into pressure contact with the joint body end 14a (see figure (b)). It becomes a functional pipe joint.

FIG. 3 shows a third embodiment.

Figure (a) shows a metal coil spring 31 as an annular body having an inner diameter slightly smaller than the outer diameter of the tube 12, and this coil spring 31 is attached externally to the end of the tube 12 as shown in figure (b). After fitting and positioning, apply an appropriate current (for example, 30 cm) to the part (A) shown in the figure.

50A). As a result, the coil spring in the part (a) through which the current flows generates heat and is instantly embedded in the thickness of the tube, resulting in a state in which the diameter of the tube opening end 12a is slightly expanded. At this time, there are almost no irregularities on the inner surface of the tube 12 (see figure (
See C). Next, as shown in FIG. 1(d), by attaching a sleeve 32 having a spiral groove on its inner circumferential surface, the same condition as in FIG. 1(a) of the first embodiment can be created. .

Therefore, by connecting the tubes in the same manner as shown in FIG. 1(b), a pipe joint having the same function can be obtained. Note that the coil spring in the part (B) shown in FIG. 3(C) is used to protect the tube from bending after the joint is attached. In each of the above embodiments, the pipe joints are made of resin, but it is of course possible to make them of metal. .

〔Effect of the invention〕

As explained above, according to the present invention, there is no need for an insert part in the joint body unlike in the past, so there is no accumulation of liquid at the connection part, and the pipe joint is also downsized, and the structure is simple and easy to assemble. In addition to this, the pipe joint can also have good sealing properties and strong pull-out strength.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the present invention, and FIG.
is a half-sectional view showing the sleeve fitted into the tube,
The same figure (with) is a half-sectional view showing the state assembled as a pipe joint, FIG. 2 is a second embodiment, and FIG. FIG. 3 is a half-sectional view showing the state in which the annular body is attached to the tube in the third embodiment; FIG. ) is a side view of the coil spring as an annular body, (b) is a diagram showing the energized part of the coil spring inserted into the tube, and (C) is
is a diagram showing the state after energization, FIG. 4(d) is a diagram showing the state where the sleeve is fitted to the part after energization, FIG. 4 is a conventional example, and FIG. 4(a) is the state before the sleeve is crimped. FIG. 3(b) is a half sectional view showing the state after the sleeve is crimped. 11 (sleeve), 21 (metal ring), 31 (coil spring)... annular body, 12...
Tube, 12a...Tube opening end, 13.
...Tightening nut, 13a...Tube insertion part, 14...Joint body.

Claims (1)

[Claims] (1) A metal annular body that fits around the end of a flexible tube to reduce its diameter and flare the open end of the tube, and a male threaded part of the joint body through which the tube is inserted. and a tightening nut that presses the annular body toward the joint body at the tube insertion portion to press the tube opening end to the truncated conical end of the joint body. Fittings.