JPH074392Y2 - Spigot fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a spigot joint, and more particularly to, for example, an electric fusion spigot joint.

[Prior art]

Referring to FIG. 3A, the conventional spigot joint 1 has a joint 2
The spigot portion 4 that fits into the receptacle 3 is formed, and the root end of the spigot portion 4 is formed with a receptacle end contact surface 5 that rises vertically from the outer surface of the spigot portion 4 and contacts the end surface of the receptacle 3. .

[Problems to be solved by the device]

In the conventional spigot joint 1, since the receiving end contact surface 5 rises vertically from the outer surface of the spigot portion 4 at the rising portion 6, stress concentration occurs in the rising portion 6 and it is easily damaged. There was a point.

Therefore, recently, in order to avoid such stress concentration, a spigot joint 1'shown in FIG. 3B or 3C in which the rising portion 6 is rounded so that the cross-sectional shape changes gently is used. Sometimes. However, in this case, the following different problems occurred.

That is, in the example shown in FIG. 3B, since the rising portion 6 is rounded, a gap t is created between the socket 3 and the socket end contact surface 5, and at the same time, the spigot end of the socket 3 is formed. A gap t ′ is formed between the contact surface 7 and the end surface of the spigot portion 4. Therefore, in this case, in order to eliminate the gap t ', the total length of the spigot portion 4 must be made longer by t'than in the conventional case. Not only that, 3B
In the example shown in the figure, another problem arises in that a bending moment is easily applied due to the gap t.

Further, in the example shown in FIG. 3C, the rising portion 6 is rounded, and at the same time, the inner peripheral edge of the end face of the socket 3 of the joint 2 is chamfered. In this way, since the gap t shown in FIG. 3B does not occur, the length of the spigot portion 4 can be the same as the conventional one, and the swinging of the joint 2 due to the bending moment can be prevented. However, in this case, since the fusion length is reduced by the amount of chamfering, another problem that the fusion strength is weakened occurs.

Therefore, the main purpose of this invention is to provide a structurally stronger spigot joint.

[Means for Solving the Problems]

Briefly, the present invention is directed to a spigot joint having a spigot portion that fits into a receptacle and a receptacle end contact surface that rises from the outer surface of the spigot portion and abuts the receptacle end. The spigot joint is characterized in that a smooth annular concave portion is formed in a depth direction of a receiving end contact surface while leaving an outer peripheral portion of the surface.

[Action]

The joint is connected to the outer peripheral portion of the socket end contact surface so that the socket end contacts. Therefore, the bending moment generated due to the gap between the receiving end contact surface and the receiving end as in the conventional example of FIG. 3B is reduced. Further, since the annular concave portion is formed in the depth direction of the receiving end contact surface, it is not necessary to chamfer the receiving side unlike the conventional example of FIG. 3C. Therefore, a sufficient margin for fusion is secured. Further, the annular recess can avoid the stress concentration in that portion, as in the conventional R filleting.

[Effect of device]

According to this invention, stress concentration can be avoided, the bending moment can be reduced, and a sufficient fusion allowance can be secured, so that a spigot joint having a large structural appropriate strength as a whole can be obtained.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the embodiments below with reference to the drawings.

〔Example〕

Referring to FIG. 1, the spigot joint 10 of this embodiment is
For example, the joint body 12 is formed as an integral body made of synthetic resin such as polybutadiene. The outer diameter of the joint body 12 is made substantially equal to the outer diameter of the receiving portion 16 of the joint 14 connected thereto, and extends from the receiving end contact portion 18 of the joint body 12 to fit into the receiving portion 16. The spigot portion 20 is formed.

In the spigot portion 20, its outer diameter and the length from the receptacle end contact portion 18 to the end surface are made substantially equal to the inner diameter of the receptacle portion 16 and its length from the spigot end contact portion 22 to the end surface.
An annular recess 24 having a semicircular cross section is formed at the base of the spigot portion 20 and the receiving end contact portion 18 from the receiving end contact portion 18 toward the joint body 12. The diameter of the cross-section semicircle of the annular recess 24 is
The thickness is made smaller than the thickness of the receiving end contact portion 18, so that the annular receiving end contact portion 18 that contacts the end surface of the receiving portion 16 is left outside the annular recess 24.

The joint 14 connected to the spigot joint 10 includes a receiving portion 16 that fits with the spigot portion 20, and the root portion of the receiving portion 16 rises from the inner surface thereof and contacts the end surface of the spigot portion 20. A spigot end contact portion 22 is formed.

Then, when the spigot joint 10 and the joint 14 are connected by electric fusion, the socket 16 is fitted on the outer surface of the spigot 20. At this time, the end surface of the spigot portion 20 and the spigot end contact portion 22 come into contact with each other, and the end surface of the receiving portion 16 and the reception end contact portion 18 come into contact with each other. Then, a heating wire (not shown) is energized to melt the inner surface of the socket portion 16 of the joint 14 and the outer surface of the spigot portion 20 of the spigot joint 10 and bond them to each other.

As described above, in the spigot joint 10, the action of the annular recess 24 allows the receptacle 16 and the receptacle end abutting portion 18 to come into close contact with each other similarly to the conventional spigot joint 1 (FIG. 3A), so that the spigot The bending moment applied to the joint 10 and the joint 14 can be reduced, and a sufficient fusion allowance can be secured. Moreover, the annular recess 24 can prevent stress from concentrating on that portion. Therefore, according to the spigot joint of this embodiment, the structural strength as a whole is shown in FIG.
It can be greatly increased compared to the conventional one shown in FIG. 3B or FIG. 3C.

The sectional shape of the annular recess 24 may be a semi-oval shape as shown in FIG. 2A or a semi-elliptical shape as shown in FIG. 2B, in addition to the semi-circular shape as shown in FIG.

Further, the spigot portion 20 may be formed in a straight shape, or may be formed in a tapered shape so as to fit with a receiving portion formed in a tapered shape.

Further, in the above-mentioned embodiment, the embodiment in which the present invention is applied to the electric fusion spigot joint has been described.
Of course, it can be applied to other types such as an adhesive type.

Further, the spigot joint of the present invention can be used as a joint for cheese, elbow, reducer, cloth, header and the like.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2A is a partially enlarged sectional view showing a modified example of the annular recess of the embodiment shown in FIG. FIG. 2B is a partially enlarged sectional view showing another modification of the annular recess of the embodiment shown in FIG. 3A to 3C are partial sectional views showing a conventional example. In the figure, 10 is a spigot joint, 12 is a joint body, 14 is a joint, 16 is a receiving portion, 18 is a receiving end abutting portion, 20 is a spigot portion, 22 is a spigot end abutting portion, and 24 is an annular recess. Show.

Claims (1)

[Scope of utility model registration request] 1. A spigot joint comprising a spigot portion that fits into a receptacle and a receptacle end contact surface that rises from the outer surface of the spigot portion and contacts the receptacle end, the socket end contact surface The spigot joint is characterized in that a smooth annular concave portion is formed in a depth direction of the receiving end abutting surface while leaving an outer peripheral portion thereof.