JPH0433262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sleeved corrugated pipe made of synthetic resin that is suitably used, for example, as a drainage pipe for civil engineering, and a method for manufacturing the same.

BACKGROUND ART Recently, a synthetic resin corrugated pipe 1 having a corrugated outer peripheral surface 13 in which annular peaks 11 and troughs 12 are alternately arranged as shown in FIG. It has come to be used.

The connection of the corrugated pipes 1 is usually performed by using a corrugated pipe joint 2 having a protrusion 21 on the inner surface as shown in FIG. However, such a corrugated pipe joint 2 is manufactured and sold separately from the corrugated pipe and is relatively expensive, and the connection work is also troublesome because both corrugated pipes 1 and 1 must be inserted. It was hot.

On the other hand, in the case of a normal synthetic resin circular tube that is not a corrugated tube, the end 31 of the circular tube 3 is expanded in diameter by pushing in the diameter expanding jig 4 while heating the end 31 of the circular tube 3, as shown in FIG. Those are already on sale. A circular tube 3 whose end has been enlarged in diameter can be connected by simply inserting the next circular tube into the enlarged end 31, which is economical as no joint is required, and the connection work is also simplified. It has the advantage that it can be easily done because only one circular tube needs to be inserted.

Therefore, in the case of the corrugated pipe 1 described above, if the diameter of the end portion is enlarged in the same manner, the joint 2 becomes unnecessary and the connection work becomes easier, but in this case, the following problem occurs.

Problems to be Solved by the Invention That is, if the end of the corrugated tube 1 is heated in the same manner as described above and the diameter expanding jig 4 is pushed in, the expanded diameter end of the corrugated tube 1 as shown in FIG. The peaks 11 and troughs 12 of the portion 14 irregularly lose their shape, resulting in a significant decrease in product value. Therefore, in the case of a corrugated pipe, it is actually impossible to expand the diameter thereof, and therefore, the use of the above-mentioned corrugated pipe joint 2 has been unavoidable.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a corrugated pipe with a sleeve that is easy to connect and can be manufactured at a relatively low cost, and an efficient method for manufacturing the same.

Means for Solving the Problem In order to solve the above problem, the sleeved corrugated pipe of the present invention has a corrugated pipe having a corrugated outer peripheral surface in which annular peaks and valleys are arranged alternately. A synthetic resin sleeve having an inner diameter that is approximately the same as or slightly larger than the outer diameter of the tube is fitted halfway, and the fitting portion of the sleeve is bent into a corrugated cylindrical shape that engages with the corrugated outer peripheral surface of one end of the corrugated tube. The gist of this is that

In addition, the manufacturing method of the present invention for efficiently manufacturing such a sleeved corrugated pipe is such that a corrugated outer circumferential surface in which annular peaks and valleys are alternately connected between the two split molds for sleeve molding in an open state. an extrusion process in which one end of the corrugated tube with the molten resin is faced, the extrusion process involves extruding the molten synthetic resin into a cylindrical shape, and fitting the tip of the resin into one end of the corrugated tube; Pressing the tip fitting portion of the molten synthetic resin cylindrical body from the periphery with the corrugated tube molding surface to bend the tip fitting portion into a corrugated tube shape that engages with the corrugated outer circumferential surface of one end of the corrugated tube; The molten synthetic resin cylindrical body is closed in a bag shape with the cylindrical body bag closing portion of the split mold, and a blow is sent into the bag to close the bag-like body on the cylindrical molding surface of the split mold. and a molding step of molding a synthetic resin sleeve whose end is closed by being pressed against the end face, and a cutting step of cutting off the closed end of the synthetic resin sleeve after demolding.

Example Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 is a cross-sectional view showing one embodiment of a corrugated tube with a sleeve according to the present invention, in which numeral 1 indicates a corrugated tube made of synthetic resin, and numeral 5 indicates a synthetic resin sleeve.

The corrugated tube 1 has an annular peak 1 like the conventional one.
It has a corrugated outer peripheral surface 13 in which 1 and troughs 12 are arranged alternately, and a cylinder 15 is formed inside to smooth the flow of water, and is fused and integrated with the inner surface of the troughs 12. . The corrugated pipe 1 of this embodiment is exemplified with the assumption that it will be used as a drainage pipe for civil engineering, so no water holes are formed.
2. It goes without saying that the cylinder 15 has many small water holes formed therein.

A substantially cylindrical synthetic resin sleeve 5 having an inner diameter that is approximately the same as or slightly larger than the outer diameter of the ridge portion 11 is fitted to one end of the corrugated tube 1, and the fitting of the sleeve 5 The portion 51 is bent into a corrugated cylindrical shape that engages with the corrugated outer peripheral surface of the end portion of the corrugated tube 1, and is partially fused. Therefore, even if a force in the pulling direction is applied to the sleeve 5, it will not fall off, and even if a force in the pushing direction is applied when connecting the corrugated pipe, it will not move. In order to securely install the sleeve 5 in this way, it is desirable to fit the sleeve 5 into the end of the corrugated tube 1 by about two threads as shown in the figure; if only one thread is used, there may be some concerns about the fixing strength. There is. In addition, near the tip of this sleeve 5, there are two annular convex ribs 52, 52 for reinforcement.
is formed to prevent the sleeve 5 from being easily deformed.

The portion of the sleeve 5 other than the fitting portion 51 has a cylindrical shape with a uniform inner diameter, but in order to make the plug-in connection of the corrugated tube even more economical, the inner diameter should be gradually reduced as it approaches the tip opening. It is preferable to configure it in a lattice shape that increases in size. Furthermore,
If necessary, a protrusion or the like that fits into the trough of the corrugated tube inserted into the sleeve 5 may be provided on the inner surface of the sleeve 5 to make it difficult for the corrugated tube inserted and connected to come out.

To connect the sleeved corrugated tubes as described above, as shown by the dashed line in FIG.
This is done by inserting the other end of the corrugated pipe without a sleeve into the sleeve 5 of the other corrugated pipe 1, so compared to the conventional case where both corrugated pipes are connected using a corrugated pipe joint, the length of the corrugated pipe is One insertion work is omitted, improving work efficiency. Moreover, the fitting part 51 of the sleeve 5 is bent into a corrugated cylinder shape that engages with the corrugated outer peripheral surface of the end of the corrugated tube 1, and is partially fused and firmly attached, so that it can be easily attached during transportation etc. There is no need for the sleeve 5 to fall out of the corrugated pipe 1 or for the sleeve 5 to be pushed in during the connection operation.

Such a sleeved corrugated pipe can be efficiently manufactured by the following manufacturing method of the present invention.

First, in the extrusion process, as shown in FIG. The extruder 7 extrudes the molten synthetic resin into a cylindrical shape as shown by the dashed line, and the tip of the molten synthetic resin cylindrical body 8 is fitted into one end of the corrugated tube 1. In this case, the opening at the other end of the corrugated tube 1 is previously plugged with a plug 9, and the nozzle 10 is inserted into the corrugated tube 1 through the plug 9.

Next, in the molding process, before the molten synthetic resin cylindrical body 8 solidifies, the split molds 6, 6 are closed together as shown in FIG. The tip fitting portion 81 of the molten synthetic resin cylindrical body 8 is pressed from the periphery to bend the tip fitting portion 81 into a corrugated cylindrical shape that engages with the corrugated outer peripheral surface of the end of the corrugated tube 1. When bent in this way, the tip fitting part 81 is partially fused to the end of the corrugated tube 1. At the same time, the cylindrical bag closing portion 6 of the split molds 6, 6
At 2 and 62, the middle of the molten synthetic resin cylindrical body 8 is closed and pinched into a bag shape as shown by the dotted line, and a blow is sent into the inside of this bag body 82 from the nozzle 10 at the other end of the corrugated tube 1 to The bag-like body 82 is pressed against the cylindrical molding surfaces 63, 63 and end surfaces 64, 64 of the split molds 6, 6, to mold the synthetic resin sleeve 5 with the ends closed. In this embodiment, two concave grooves 65, 65 are carved in the cylindrical molding surfaces 63, 63, so that the synthetic resin sleeve 5 has two annular convex ribs 52,
52 is also formed at the same time.

In addition, in this example, since the case where the cylindrical body 8 of molten synthetic resin is continuously extruded is taken as an example, the cylindrical body 8 is closed into a bag shape and simultaneously pinched. If the shaped body 8 is extruded intermittently over a predetermined length, this pinching is not necessary. In this embodiment, the blow is sent from the nozzle 10 at the other end of the corrugated tube 1. For example, the inside of the molten synthetic resin bag 82 is supplied from between the cylindrical body bag closing parts 62, 62 of the split molds 6, 6. A nozzle may be provided so as to penetrate into the bag-like body 82 to feed the blow into the bag-like body 82. In short, any means that can feed the blow into the bag-like body 82 may be used.

Synthetic resin sleeve 5 with its end closed in this way
Once molded, as shown in FIG. 2C, the split molds 6, 6 are opened and demolded, the stopper 9 and nozzle 10 are removed, and the synthetic resin sleeve 5, which has been sufficiently cooled and solidified in the cutting process, is removed. The closed end 53 of the tube is cut off along the dashed line to obtain the desired sleeved corrugated tube.

When manufactured by the above method, the end of the corrugated tube 1 on which the sleeve 5 is formed is not strongly overheated, so the peaks 11 and troughs 12 of the end do not soften and deform. The corrugated cylindrical fitting portion 51 is also molded without losing its shape at the peaks and valleys, resulting in a good finish and appearance. Further, since no special equipment is required, the equipment cost does not increase and it is economical.

Effects of the Invention As is clear from the above explanation, according to the corrugated pipe with a sleeve of the present invention, the connecting work of the corrugated pipe can be easily performed, and since the adhesion strength of the sleeve is high, the sleeve can be easily attached during transportation. There's no chance of it falling off. Further, even if the cost increases slightly due to sleeve molding, the relatively expensive corrugated pipe joint is not required, so the total cost is actually reduced, which is economical.

According to the manufacturing method of the present invention, the sleeve can be molded without strongly overheating the end of the corrugated tube by applying conventional blow molding technology, resulting in a good finish and appearance, and a high commercial value. High-quality products can be mass-produced, and no special equipment is required, so there is no need to worry about increased equipment costs.

As described above, the present invention is highly effective and extremely useful.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the sleeved corrugated pipe of the present invention, and FIGS. 2A, 2B, and 2 are partial sectional views sequentially explaining the steps of an embodiment of the manufacturing method of the present invention.
Fig. 3 is a cross-sectional view for explaining the connection of a conventional corrugated pipe, Fig. 4 is a cross-sectional view of a conventional circular pipe with an enlarged end, and Fig. 5 is a corrugated pipe with an enlarged end. FIG. 1...Corrugated pipe, 5...Synthetic resin sleeve, 6...
...Divided mold for sleeve molding, 8... Molten synthetic resin cylindrical body, 82... Molten synthetic resin bag-shaped body, 11...
Peak portion, 12... Valley portion, 13... Waveform outer peripheral surface, 51
. . . Fitting portion, 53 . . . Closed end portion, 61 .

Claims (1)

[Scope of Claims] 1. A synthetic resin sleeve having an inner diameter approximately equal to or slightly larger than the outer diameter of the crests at one end of a corrugated tube having a wavy outer peripheral surface in which annular ridges and troughs are arranged alternately. A corrugated pipe with a sleeve, which is bent into a corrugated cylinder shape in which the sleeve is fitted halfway and the fitting part of the sleeve meshes with the corrugated outer peripheral surface of one end of the corrugated tube. 2. One end of a corrugated tube with a corrugated outer circumferential surface in which annular peaks and troughs are alternately connected is exposed between both sleeve-forming split molds in an open state, and the molten synthetic resin is formed into a cylindrical shape. an extrusion step of extruding the molten synthetic resin cylindrical body and fitting its tip into one end of the corrugated tube; and closing the split molds and using the corrugated tube molding surface of the split mold to fit the tip of the molten synthetic resin cylindrical body to one end of the corrugated tube. is pressed from the periphery to bend the tip fitting part into a corrugated cylinder shape that engages with the corrugated outer circumferential surface of one end of the corrugated tube, and the molten synthetic resin cylinder is bent at the cylindrical body bag closing part of the split mold. The body is closed in a bag shape, and a blower is sent into the inside of the bag-like body to press the bag-like body against the cylindrical molding surface and end face of the split mold to form a synthetic resin sleeve with the end closed. A method for manufacturing a corrugated tube with a sleeve, comprising: a molding step; and a cutting step of cutting off the closed end of the synthetic resin sleeve after demolding.