JPS635634B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pipe joint, and more particularly to a pipe joint made of synthetic resin that can increase tightening torque while maintaining the sealing properties of extremely low air leakage.

For a time, all-synthetic resin pipe fittings were used to replace the conventionally widely used metal pipe fittings, but it cannot be said that the various properties of synthetic resin were fully utilized, and pipe fittings The threaded part and hexagonal tightening part are frequently damaged and the durability is poor, so its uses are extremely limited. Screws originally made of synthetic resin have the characteristic of plastic deformation and improved sealing performance when tightened sufficiently, but synthetic resin has the tightening pressure resistance that metal has, which enables sufficient tightening. As a result, damage occurs in each part, and this damage is propagated to other parts, leading to serious accidents in which the entire part breaks, which hinders the widespread use of synthetic resin pipe joints that can be made at low cost. ing.

Therefore, it has been desired to develop a pipe joint that has the sufficient strength of metal in the hexagonal tightening part and the sealing properties of synthetic resin in the threaded part.

This invention was made in view of the above points,
In addition to having sufficient strength of metal in the tightening part,
The purpose of this invention is to provide a pipe joint with a threaded portion that has sealing properties.

In order to achieve the above object, the present invention has the following configuration.

In other words, the joint body has a tightening part with a polygonal outer shape, such as a wrench hook, in the middle, and a male threaded part for external connection is formed at one end, and a joint body provided at the other end of the joint body. In the pipe joint, the joint body is composed of a synthetic resin molded product consisting of a core metal and a resin part integrated with the core metal, and the core metal is connected to the tightening part of the joint body. The outer surface is exposed from the resin part at the corner of the tightening part and the vicinity thereof, and the intermediate part is provided in a recessed part so as to connect the front and rear resin parts that sandwich the core metal. A small-diameter cylindrical part formed in the chrysanthemum-shaped part, in which the part corresponding to the male threaded part of the joint body is exposed to the inner wall part of the male threaded part via a connecting part that passes through the resin part from the chrysanthemum-shaped part. It is characterized by being formed.

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

In a pipe fitting 10 having a tapered threaded portion for a gas pipe, abbreviated as a PT thread, shown in FIG. tube 1 inserted into
A locking body 16 that prevents movement of the tube in the drawing direction by having its locking end embedded in the outer wall surface of the pipe.
Then, the locking body is supported movably within a predetermined range in the axial direction of the joint body 12 in order to press the locking end of the locking body with its tip at the moving position and release the locking end from biting into the pipe. and a release ring 18. This part may be a joint of any structure, for example, it may be connected to the joint main body in an elbow shape. A pipe joint tightening portion 20 having a hexagonal cylindrical cross section is located halfway between the left and right sides of the joint body 12 made of synthetic resin, and a core bar 22 is embedded within this pipe joint tightening portion 20 . As shown in FIG. 2, the cross-sectional shape of the tightening portion of the core bar 22 is formed by forming a concave portion in the axial direction between the corners of a hexagonal thin-walled metal cylinder. to accomplish. The cross-sectional shape of the core bar 22 at a position corresponding to the tapered threaded portion 26 has a small-diameter hexagonal cylinder shape, and the chrysanthemum-shaped portion is connected to the chrysanthemum-shaped portion via a tapered connecting portion. The left end of the core metal 22 is formed by expanding a small-diameter hexagonal portion into, for example, a cylindrical shape. The outer circumferential surface of the core metal 22 starting from the tapered portion, extending over the small-diameter hexagonal cylindrical portion and ending at the cylindrical end portion is a synthetic resin tapered threaded portion 26, which is used to transmit torque to the tapered threaded portion 26. The interior of the concave portion 24 in the chrysanthemum-shaped portion of the core bar 22 is integrally filled with synthetic resin. Also, taper thread part 2
6. The inner small-diameter hexagonal cylindrical core part also contributes to torque transmission. The inside of the chrysanthemum-shaped part of the core bar 22 is also integrally filled with synthetic resin, and the only outwardly exposed parts of the core bar 22 are the corners of the hexagonal part of the pipe joint tightening part and the vicinity thereof. . Note that the resin parts before and after the core bar are connected to each other by a recessed part. Note that the chrysanthemum-shaped portion is not limited to a hexagonal shape, but may be other polygonal shapes such as a quadrangular shape.

On the other hand, FIG. 3 shows a front view of the core bar 22, and the fourth
The figure is a sectional view showing the AOA' cross section of the core metal 22.
The joint body 12 of this pipe joint can be molded in one step by inserting a cylindrical core metal 22 and performing synthetic resin insert molding.

In the pipe joint 10 obtained in this way, only the strength and breakage prevention ability can be provided to the metal, and the metal part of the core metal is always exposed at the position where a tightening tool such as a spanner comes into contact. Therefore, even if a strong tightening torque is applied, not only will the synthetic resin not break, but it will not give any such uneasy impression. Since the threaded portion consisting of the tapered threaded portion is made of synthetic resin, high sealing performance is maintained due to the deformation of the thread itself, making it unnecessary to apply Teflon (registered trademark). Since the corners of the hexagonal portion and the vicinity thereof are metal parts, they can withstand high torque not only during tightening but also during removal. In addition, most of the outer periphery of the metal core 22 and the inner periphery of the chrysanthemum-shaped portion that has a rib-reinforcing effect are filled with a single synthetic resin, which reinforces the thin metal core and makes it even more durable. Impact strength can be increased, and it is always closely integrated and does not come apart even under high torque.

To give another example, instead of the metal core metal, various other materials having strength and impact resistance equivalent to metals, such as fine ceramic core metals, can be used. Further, in addition to the pipe joints shown in the embodiments, the idea of the present invention can be applied to bolt-shaped pipe joints, and in the broadest sense, the bolt itself as a fastener. In this specification, exposed means visible from the outside, and if the synthetic resin is semi-transparent, if the surface is slightly covered with the synthetic resin, it is considered exposed. be. The recessed portion may partially form a communicating hole portion that communicates with the interior, or may be a reinforcing portion such as a wing-like or thorn-like portion.

As described above, the present invention provides the following remarkable effects.

(a) The core metal passes diagonally through the resin part, and one end is exposed to the outside at the tightening part, and the other end is exposed to the inner wall of the male thread part, so the reinforcing effect of the resin part of the core metal is enhanced. It becomes extremely large. Moreover, since the resin part is connected to the front and back by sandwiching the core metal by the recessed part of the core metal, there is no possibility that the core metal and the resin part will separate, and the adhesion strength between the core metal and the resin part is excellent.

(b) Since the chrysanthemum-shaped portion of the core metal has a cylindrical shape with unevenness on the circumferential surface, the strength of the core metal itself is even greater in the direction of tightening with a tightening tool such as a spanner. , can withstand high torque during tightening or removal. Furthermore, since the male threaded portion is made of resin, the necessary high sealing performance is ensured. Furthermore, if the small-diameter cylindrical portion of the core metal is formed to have a hexagonal cross section, it can be used as a tightening hole for a hexagonal wrench.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of a pipe joint, FIG. 2 is a partial left side view of a pipe joint, FIG. 3 is a front view of a cored bar, and FIG. 4 is a cored bar. of
It is an AOA′ cross-sectional view. 10...Pipe fitting, 12...Joint body, 14...
Pipe, 16... Locking body, 18... Release ring, 20
... Pipe joint tightening part, 22 ... Core metal, 24 ... Recessed part, 26 ... Tapered thread part.

Claims (1)

[Scope of Claims] 1. A joint body having a tightening part with a polygonal outer shape, such as a wrench hook, in the middle part, and a male screw part for external connection formed on one end side, and the other parts of the joint body. A pipe joint comprising a joint part provided on an end side for connecting pipes, wherein the joint body is composed of a synthetic resin molded product consisting of a core metal and a resin part integrated with the core metal, and the core metal is connected to the joint part. The part corresponding to the tightening part of the main body is
The outer surface is exposed from the resin part at the corner of the tightening part and its vicinity, and the intermediate part is a chrysanthemum-shaped part provided in the concave part to connect the front and rear resin parts that sandwich the core metal. The part that corresponds to the male threaded part of the joint body is formed into a small diameter cylindrical part that is exposed to the inner wall surface of the male threaded part via a communication part that passes through the resin part from the chrysanthemum shaped part. A pipe joint featuring: 2. The pipe joint according to claim 1, wherein the small cylindrical portion is formed as a hexagonal wrench insertion tube.