JP2003004182A - Insertion protrusion molding method - Google Patents

Abstract

(57) [Summary] [Problem] To form an insertion port projection at a construction site, it can be applied even with a thin pipe, there is little noise at the time of construction, and it is easy and troublesome to perform the construction. Make it an issue. An outer surface contour shape has a shape satisfying a specified dimension of an insertion projection, and a circumferential groove 11 is formed on an outer peripheral surface;
An insertion ring body 10 whose inner surface shape is formed along the outer peripheral surface from the opening end of the insertion port 2 is fitted to the opening end of the insertion port 2, and then the ring body 10 is 10 and a step of welding the outer peripheral surface of the insertion opening 2.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an insertion port projection. 2. Description of the Related Art A pipe joint 1 shown in FIG. 7 is known as a pipe joint for preventing detachment of a ductile cast iron pipe. [0003] The pipe joint 1 has an insertion port 2 having an insertion port projection 3 formed therein, and a receiving port 4 having a lock ring 5 fitted on an inner surface thereof.
When the pull-out force acts on the pipe joint 1, the insertion projection 3 and the lock ring 5 are engaged with each other to prevent the pipe joint 1 from coming off. In the drawing, reference numeral 6 denotes a centering ring, and 2s denotes a sealing rubber ring for sealing between the inner surface of the receiving port 4 and the outer surface of the insertion port 2. By the way, in pipe laying work, it is often necessary to cut the pipe at a construction site. Therefore, in such a case, when the pipe is cut, it becomes necessary to form the insertion projection 3 at a new pipe end. Conventionally, the insertion port projection 3 is formed at the construction site by cutting the pipe as shown on the left side of FIG. 8 and using a keel cutter (not shown) at the pipe end to be newly inserted. As shown in the center of the figure, the concave groove 8 on the outer periphery of the tube end and the tapered surface 9 on the tube end are cut and formed, and then a split opening ring body prepared for each diameter of the tube as shown on the right side of FIG. 5 is fitted into the concave groove 8, and as shown in FIG. 9, the connecting piece 7 is spanned over the split portion 5a, and both ends are connected in a ring by fastening with rivets 7a, 7a or the like. Part 3
And that is being done. However, the method of forming the insertion projection 3 is as follows.
Since the circumferential groove 8 for fixing the insertion ring body 5 is formed on the outer periphery of the pipe, it can be implemented only for a thick pipe, and is difficult to be applied to a thin pipe.
There is a problem that it takes time and effort to perform the work, and that the work requires grinding so that the noise is large. SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and is applicable to forming an insertion projection at a construction site, even if the pipe has a small thickness, and reduces noise during construction. The task was to make the work very simple and easy. According to the present invention, there is provided a method for forming an insertion port having a shape in which an outer contour shape satisfies a specified dimension of the insertion port, and which is melted and welded to an outer peripheral surface during welding. An insertion ring body in which a circumferential concave groove having a bottom surface having a thickness such that it is welded to the outer surface is formed, and the inner surface shape is formed along the outer peripheral surface from the opening end of the insertion opening, is inserted into the insertion opening. The ring body is inserted into the opening end and then welded to the outer peripheral surface of the opening at the circumferential groove portion. [0009] Therefore, the fitting process of the insertion projection is completed only by fitting a ring body prepared in advance to the pipe end to the pipe end after cutting the pipe and welding the circumferential groove portion. The insertion projection can be formed without the noise of grinding, and without fear of a decrease in strength even with a thin-walled tube. The insertion ring has an inner diameter equal to or smaller than the outer diameter of the insertion port, and can be pressed into the outer surface of the insertion port by using a tool such as a hammer. Next, an embodiment of the present invention will be described. FIG. 1 is an enlarged sectional view of a main part showing one embodiment of the present invention, and is a sectional view of an insertion ring body. In FIG. 1, an insertion ring body 10 has a thickness T and an outer surface contour shape satisfying the specifications of an insertion protrusion, and an inner surface shape has an opening end 2a of an insertion hole 2 as shown by a dotted line. As shown in the drawing, the opening end 2a is formed so as to cover the outer peripheral surface 2c of the insertion opening 2 through the tapered surface 2b.
Radially expanding surface 10a and inner surface tapered surface 10b along
It has a shape having a short cylindrical inner peripheral surface 10c. In the above description, the shape that satisfies the specification of the insertion port protrusion means that, when the insertion ring body 10 is applied to the outer surface of the insertion port 2, the thickness T of the cross section is equal to the outer surface of the insertion port 2 and the inner surface of the receiving port 4. Between the lock ring 5 and the insertion ring 2.
It refers to a shape having a tapered surface 10d through which the diameter of the lock ring 5 can be substantially increased at the time of insertion. An outer peripheral groove 11 is formed on the outer peripheral surface of the insertion ring body. The outer circumferential groove 11 has a thickness such that the bottom surface is melted during welding and welded to the outer surface of the insertion opening. The inner diameter r of the insertion ring body 10 is made equal to or slightly smaller than the outer diameter of the insertion port 2 to be inserted, and can be pressed into the outer surface of the insertion port 2 by using a tool such as a hammer. ing. In order to form an insertion port protrusion using the insertion port ring body 10, after cutting a pipe at a pipe laying site, FIG.
As shown in the figure, the pipe end surface of the portion which becomes the insertion port 2 is tapered by a grinder (not shown) or the like to form a tapered surface 2b.
Is molded. Next, as shown in FIG. 4, the insertion ring body 10 is applied to the end face of the insertion opening 2, the hitting plate 13 is applied thereto, and the inner surface 10a to 10c is inserted as shown in FIG. Fit along the mouth outer surfaces 2a to 2c. Since the tapered surface 10b is formed on the inner surface of the ring body 10, it is in contact with the outer surface of the insertion opening 2 without any gap.
Then, as shown in FIG. 6, welding is performed from the groove 11 to elevate the weld bead 13, and at the same time, the bottom of the groove 11 is melted and welded to the outer surface of the insertion opening 2. Therefore, since the insertion ring body 10 is welded to the entire circumference of the insertion port 2 at the concave groove 11, the adhesion strength to the insertion port is very strong and can withstand a large pulling force. Further, since the groove is not machined in the insertion port itself, there is no danger that the strength of the insertion port will be impaired, so that the projection can be provided safely even with a thin pipe. Next, an embodiment of the present invention will be described. Insert ring 1
A ring body 10 having an inner diameter equal to the outer diameter of the insertion port or having an inner diameter smaller by 1.2 mm than the outer diameter was prepared as 0, and used for the insertion port of the ductile cast iron pipe. The material of the insertion ring body 10 was a material equivalent to FCD400. The above-mentioned insertion ring body 10 is applied to a pipe,
As shown in FIG. 4, a hammer 14 was used to hit the end face uniformly over the entire circumference of the end face via the backing plate 13 and fitted as shown in FIG. Thereafter, the inside of the groove 11 was welded as shown in FIG. 6 under the conditions of a welding speed of 1100 mm / min, a welding current of 260 to 300 amperes and a welding voltage of 25 to 28 volts. The insertion port 2 to which the insertion port ring body 10 was welded was inserted into the reception port 4 to connect the pipes, and the test for preventing the detachment was performed. In each case, 3DkN (0.3Dtf, D: nominal diameter mm) was prevented. Power was gained. As described above, according to the method for forming an insertion port projection according to the present invention, the insertion ring body can be elastically fitted to the outer periphery of the insertion port and the outer surface of the insertion port can be elastically fitted. Since the groove is welded to the outer surface of the insertion port with the concave groove on the outer periphery of the ring body without grinding, the insertion port protrusion can be provided safely even if the thickness of the insertion port is thin. In addition, the detachment preventing force can be made sufficiently strong.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side view of a main part of an insertion ring used in the method of the present invention. FIG. 2 is a front view of the insertion ring of FIG. 1; FIG. 3 is a cutaway side view of a main part of the insertion opening. FIG. 4 is a fragmentary side view showing a state where the method of the present invention is carried out. FIG. 5 is a cutaway side view of a main part in a state where an insertion ring is fitted into the insertion opening. FIG. 6 is a fragmentary side view showing a state where welding is performed from a concave groove of the insertion ring. FIG. 7 is a sectional view of a conventional pipe joint. FIG. 8 is an explanatory view showing a conventional process of forming a convex portion on a cut tube end. FIG. 9 is a fragmentary front view showing a mounting state of a conventional insertion ring. [Description of Reference Code] 2 Insertion opening 3 Insertion projection 10 Insertion ring 10a Radially expanding surface 10b Internal taper surface 10c Short cylindrical inner peripheral surface 10d Tapered surface 10e Outer peripheral surface 11 of insertion ring body Outer peripheral groove

Claims (1)

Claims: 1. A thickness such that the thickness and the contour of the outer surface satisfy a specified dimension of the insertion projection, and the outer peripheral surface is melted during welding and is welded to the outer surface of the insertion opening. An insertion ring body in which a circumferential concave groove serving as a bottom surface is formed, and an inner surface shape is formed along the outer peripheral surface from the opening end of the insertion opening, is fitted to the insertion opening opening end, and then, A method of forming an insertion port protrusion, which comprises a step of inserting the ring body in a circumferential groove portion and welding the ring body to an outer peripheral surface of the opening.