JPS58114912A - Manufacture of branch pipe for sewerage - Google Patents

Abstract

PURPOSE:To produce a branch pipe for sewerage at a low cost that is durable against vibrations, impact or the like, by forming an intermediate of a resin comprising a pipe body that has a saddle flange around the outer circumference of one end thereof, softening the other end by heating, and expanding said other end radially outward. CONSTITUTION:A thermoplasitc resin is injection molded to be formed into the pipe body (intermediate) 1 having the saddle flange 12 around the outer circumference of one end thereof. Then after the other end of the pipe body 1 is heated, for example, by immersing it in an oil heated to from about 120 to 150 deg.C, the other end of the pipe body 1 is surrounded by an outer mold 2, while an inner mold 3 is inserted into the pipe body 1 to expand the diameter of the pipe body 1 using a holding section 31 so that the pipe body 1 is clamped between the holding section 31 and the outer mold 2 (the reference numeral 32 indicates an air-tightened section and the reference numeral 4 indicates a packing). Then a fluid pressurized to about from 8 to 15kg/cm<2> is forced into the pipe body 1 via an introduction opening 11 to expand the pipe body 1 so that the pipe body 1 comes in contact with the inner wall surface of the outer mold 2 (the reference numeral 21 indicates a vent) thereby forming a branch pipe for sewerage having the port 11, the pipe body 1 and the saddle flange 12 integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a sewage branch pipe in which a saddle collar and a pipe body having a socket are integrated.

Generally, when taking out a branch pipe from a main sewage pipe, a sewage branch pipe is used that has a saddle collar on the outer periphery of one end and a socket with an enlarged diameter on the other end. The branch pipe can be made by (1) integrally injection molding a branch pipe having a socket and a saddle flange, or (2) blow molding a socket on the pipe body, and then molding the and h separately. The method used was to use adhesive to join the saddle collars.

However, in the former case (1), since the socket is undercut, the injection mold becomes expensive, and the cost of the product inevitably increases. Also the latter (
In the case of 2), there was a drawback that it was easily damaged when subjected to vibrations, shocks, etc.

In other words, the sewage branch pipe is adhesively bonded to the outer periphery of the main pipe via the saddle flange, but when a load in the axial direction of the sewage pipe, a bending moment, etc. is applied to the sewage branch pipe, the pipe body with the saddle flange and the socket Accidents have occurred in which the adhesive between the sewage pipes has peeled off, causing the sewage branch pipes to fall into the main pipes, causing water leaks, or preventing water from flowing through one main pipe.

The present invention eliminates the drawbacks of the conventional branch pipes, can be manufactured at low cost, and the saddle collar and the pipe body having the socket are integrated to prevent the pipe from falling into the main sewage pipe. The present invention provides a method for manufacturing a sewage branch pipe that can reliably prevent the problem.

V Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 7 is a longitudinal sectional view showing an intermediate product obtained by injection molding, and FIG. FIG. 3 is a longitudinal sectional view of a sewage branch pipe obtained by the manufacturing method of the present invention.

In the present invention, first, in the first stage manufacturing process, as shown in FIG. 7, an intermediate product having a saddle flange protruding from the outer periphery of one end of the tube is molded. This intermediate product is obtained by injecting a molten thermoplastic resin into a cavity made up of an outer mold and an inner mold. The intermediate product shown in Fig. 1 has the saddle flange /, 2 protruding from the tube at a slight angle with respect to the tube axis of the tube body. Depending on the product, it may be made to protrude in a direction perpendicular to the tube axis.

Next, the other end of this intermediate product, that is, the saddle tsuba/-2
After softening the end of the pipe on the side from which it does not protrude using an appropriate heating means such as immersing it in oil at /-20 to /jθ℃ for a certain period of time, surround it with an outer mold 7, and seal the socket. Molding〇In this first step of the molding process, the tube is surrounded by an outer mold, and a pressurized fluid such as air, water, oil, etc. is applied to the inside of the tube to cause it to bulge in the outer circumferential direction. This will be explained with reference to FIG. 2, which shows a specific example.

In the figure, reference numeral 2 denotes an outer mold formed in half, and an air vent hole communicating with the molding inner wall surface is found in the wall of the outer mold.
is provided. It is a 3-hole mold.

The inner mold 3 has a gripping part 3/ having a hole 3// for introducing pressurized fluid by enlarging the diameter of the end part of the pipe body/, and an airtight part 3/.
It is composed of 2. The airtight part 32 compresses the packing between the core 3.22 fixed to the tip of the grip part 3/ and the connecting rod 33 and the pressing member 3-/ to maintain airtightness inside the pipe body. It is configured so that it can be retained.

After surrounding the end of the tube with the outer mold, the inner mold 3 is inserted into the tube and the diameter is expanded with the gripping part 3, and the end is wrapped around the outer mold. be held between. Next, connecting rod 3
3 to compress the packing between the pressing member 3-2/ and the core 322, maintain airtightness inside the tube, and then pass through the hole 3-2 into the tube. ~/jkg/d of pressurized fluid is introduced. Due to the action of this pressurized fluid, the tube expands until it comes into close contact with the molding inner wall surface of the outer mold, forming a socket with an enlarged diameter. When the mold is opened and taken out,
As shown in FIG. 3, a sewage branch pipe is obtained in which the pipe body / having the socket / and the saddle collar / 2 are integrated.

As detailed above, the sewage branch pipe obtained by the present invention has a structure in which the pipe body having the socket and the saddle collar are integrally molded, so it can be manufactured at a lower cost compared to conventional sewage branch pipes. Instead, when constructing sewage piping using this, there is no risk of it falling into the main pipe even if subjected to vibrations, impact, etc., and branch pipes can be reliably removed. It is.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention; Figure 1 is a longitudinal sectional view showing an intermediate product obtained by injection molding; Figure 1 is a longitudinal cross-sectional view showing an intermediate product obtained by injection molding; Fig. 3 is a longitudinal sectional view of a sewage branch pipe obtained by the manufacturing method of the present invention. ／・・・・・・・Pipe body, //, ・・Song/Socket, /7
!・・・・・・Saddle tsuba, Ko...beating/outer mold,
3...Inner mold

Claims (1)

[Claims] In manufacturing a sewage branch pipe that has a saddle flange on the outer periphery of one end of the tube and an enlarged diameter socket on the other end, first, the tube body with the saddle flange on the outer periphery of one end is integrally molded by injection molding, and then The other end of the tube is heated and softened, and then surrounded by an outer mold. A method for manufacturing a sewage branch pipe, which comprises introducing a pressurized fluid into the pipe body and expanding the pipe until it comes into close contact with the molded inner wall surface of an outer mold, thereby forming a socket with an enlarged diameter.