JP2549944Y2 - Bayonet fitting - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bayonet joint suitable for connecting pipes used for water supply pipes and the like.

[0002]

2. Description of the Related Art FIG. 2 shows a known plug-in joint of this type. That is, the bayonet joint includes the tubular joint body 1, the lock ring 2, and the gasket 3. The tubular joint body 1 is formed by pressing a steel pipe or a stainless steel pipe, and is formed with an inclined step portion 11 for regulating the insertion amount of the pipe P in the vicinity of the central portion in the axial direction. Steps 1 projecting radially outward perpendicular to the axis C formed at both ends
2 and 12 to the insertion openings 13 and 13 at both ends in the axial direction, large-diameter portions 14 and 14 parallel to the axis C and large-diameter portions 14 and 14.
The taper portions 15, 15 whose diameters gradually decrease from the axially outer end 14 to the insertion ports 13, 13 are formed. The lock ring 2 is made of metal such as stainless steel and has an outer diameter of the taper inner surface 1 of the taper portion 15.
It is set to a value slightly smaller than the maximum inner diameter of 5A, and a value smaller than the minimum inner diameter, that is, a value relatively larger than the diameter of the insertion port 13. As shown in FIG. ing. Therefore, the lock ring 2 is configured to be able to expand and contract. The gasket 3 shown in FIG. 2 is formed into an annular shape by an elastic material such as rubber, is housed in the large-diameter portions 14, 14 of the joint body 1, and has a metallic annular shape between its axial outer end face and the lock ring 2. Are provided.

In such a plug-in joint, for example, as shown in FIG. 4, when a resin pipe P fitted with a stiffener S at the pipe end is connected, the end of the pipe P is connected to the insertion port 13 of the joint body 1. , 13. As a result, the lock ring 2 is retracted until it is pushed by the pipe P and hits the retainer 16, and the retainer 16 hits the gasket 3 and presses the gasket 3 against the step portion 12. In this state, the lock ring 2 2 is pushed and expanded by the pipe P and fitted to the pipe P outside. Further, as shown in FIG. 5, the connection of the pipe P is completed by inserting the pipe P deeply until it comes into contact with the inclined step portion 11. When the connection of the pipe P is completed, the gasket 3 is sandwiched and compressed by the large-diameter portion 14 of the joint main body 1 and the pipe P, whereby the sealing property between the joint main body 1 and the pipe P is ensured and watertightness is maintained. Is done.

[0004] On the other hand, when the pipe P and the joint body 1 are relatively moved in the direction in which the pipe P is withdrawn while the pipe P is connected to the joint body 1, the lock ring 2 externally fitted to the pipe P is connected to the pipe P. Co-move. When the movement amount at this time reaches a predetermined value,
As shown in FIG. 6, the lock ring 2 strongly contacts the taper inner surface 15A of the taper portion 15, and the lock ring 2 is contracted by the taper inner surface 15A and reduced in diameter by the subsequent movement.
When the diameter of the lock ring 2 is reduced in this way, the pipe P is strongly held by the lock ring 2 and is prevented from falling off.

In the conventional joint body 1, the stepped portions 12, 12 are formed by bending the bent portion X in a radially outward direction perpendicular to the axis C. Therefore, cracks may occur due to stress concentration at the bent portions X when the step portions 12 and 12 are pressed, or stress cracks may be generated at the bent portions X after the step portions 12 and 12 are formed. It has. Further, the tensile force when the pipe P and the joint main body 1 are relatively moved in the drawing direction of the pipe P is concentrated on the bent portion X and is loaded. As a result, a crack may occur in the bent portion X. Moreover, since one metal annular retainer 16 is disposed only between the axially outer end surface of the gasket 3 and the lock ring 2, the gasket 3 is strongly compressed in the axial direction by the retainer 16, It is not possible to reliably seal the space between the joint body 1 and the pipe P to enhance the sealability.

[0006]

The problem to be solved is that the stress concentration occurs in the bent portion during the press working of the step portion to cause cracks, or stress corrosion occurs in the bent portion after the step portion is formed. When the pipe and the joint body are relatively moved in the direction in which the pipe is pulled out, the tensile force is concentrated on the bent portion, and the crack is generated at the bent portion.
The axial compression force of the gasket by the nut is weak, so that it is impossible to reliably seal the space between the joint body and the pipe and to ensure high sealing performance.

[0007]

According to the present invention, there is provided a large-diameter portion for accommodating a gasket from a radially extending step formed at both ends in the axial direction to insertion holes at both axial ends. A cylindrical joint body having a tapered portion that gradually reduces in diameter from the outermost end in the axial direction to the insertion port, and a pipe that is externally fitted to a pipe inserted into the joint body from the insertion port, and the pipe is pulled out in the drawing direction. In a bayonet joint provided with a lock ring that is reduced in diameter by contacting the inner surface of the taper part by moving together with the pipe when the step part moves, the step part is formed to be smoothly curved, A retainer is arranged on both sides in the axial direction of the gasket, eliminating stress concentration at the time of press working of the step, avoiding stress corrosion after the formation of the step, and extending the pipe in the drawing direction. Tube and fitting body Avoiding concentration load of the tensile force when moving, thereby preventing the occurrence of cracks in the step portion,
Retainers arranged on both sides of the gasket in the axial direction increase the axial compressive force of the gasket, reliably seal the space between the joint body and the pipe, and achieve the object of ensuring high sealing performance. .

[0008]

According to the present invention, since the step portion is formed to be curved in an arc shape, stress concentration does not occur when the step portion is pressed. As a result, stress corrosion after the formation of the step can be avoided. In addition, it is possible to avoid a concentrated load of a tensile force when the pipe and the joint body relatively move in the pipe pulling direction. Further, since a strong compressive force is applied to the gasket by the retainers arranged on both sides in the axial direction, the sealing force between the joint body and the pipe is increased.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the tubular joint body 1 is formed by pressing a steel pipe or a stainless steel pipe, and has an inclined step portion 11 that regulates an insertion amount of the pipe P near an axial center. Are formed at both ends in the axial direction so as to smoothly bend and project outward in the radial direction.
The large diameter portion 1 parallel to the axis C extends from the steps 12, 12 to the insertion ports 13, 13 at both ends in the axial direction.
And taper portions 15 and 1 whose diameters gradually decrease from the axially outer ends of the large diameter portions 14 and 14 to the insertion ports 13 and 13.
5 is formed. Further, metal annular retainers 16, 16 are arranged at both axial ends of the gasket 3.

As described above, since the steps 12 are formed to be smoothly curved, stress concentration does not occur when the steps 12 are pressed. Therefore, cracks do not occur in the step portions 12 and 12. Further, there is no inconvenience that a crack is generated due to stress corrosion after the formation of the step portions 12 and 12. Further, when the pipe P and the joint body 1 relatively move in the pulling-out direction of the pipe P, a tensile force is applied to the steps 12, 12 via the lock ring 2 and the taper section 15, but the conventional steps are used. Since the loads are not concentrated as in the case of 12, 12, no crack is generated in the step portions 12, 12 due to the relative movement of the pipe P and the joint body 1. Further, since a strong compressive force is applied to the gasket 3 by the retainers 16 and 16 arranged on both sides in the axial direction of the gasket 3, the space between the joint body 1 and the pipe P is reliably sealed, and a high seal is provided. Characteristics can be secured.

[0011]

As described above, according to the present invention, since the step portion of the joint body is formed to be smoothly curved, stress concentration at the time of pressing the step portion is eliminated, and the stress after the step portion is formed is eliminated. In addition to avoiding corrosion, it is possible to avoid the concentrated load of tensile force when the pipe and the fitting body move relatively in the pipe withdrawal direction, and it is possible to reliably prevent the generation of cracks in the stepped portion, and to prevent the gasket from moving in the axial direction. Retainers placed on both sides
With the nut, a strong compressive force is applied to the gasket to reliably seal the space between the joint body and the pipe, thereby ensuring high sealing performance.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing an embodiment of the present invention.

FIG. 2 is a half sectional view of a conventional joint body.

FIG. 3 is a front view showing an example of a lock ring.

FIG. 4 is a half sectional view showing a state in the middle of connection of pipes in a conventional bayonet joint.

FIG. 5 is a half sectional view showing a completed connection state of a pipe.

FIG. 6 is an enlarged sectional view showing an initial state of relative movement between the joint body and the pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical joint main body 2 Lock ring 3 Gasket 12 Step 13 Insertion hole of joint main body 15 Taper part of joint main body 15A Taper inner surface 16 Retainer P pipe

Claims (1)

(57) [Scope of request for utility model registration] 1. A large-diameter portion for accommodating a gasket, extending from a stepped portion formed at both ends in the axial direction extending radially outward to insertion ports at both ends in the axial direction, and from a radially outer end of the large-diameter portion. A cylindrical joint body having a tapered portion that gradually reduces in diameter toward the insertion port, and a pipe that is externally fitted to a pipe inserted into the joint body from the insertion port, and is cooperated with the pipe when the pipe moves in the withdrawal direction. In a bayonet joint provided with a lock ring that is reduced in diameter by abutting against the inner surface of the taper portion by moving, the step portion is formed to be smoothly curved, and on both sides in the axial direction of the gasket. A bayonet joint, wherein a retainer is arranged.