JPS6226299B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for closing and cutting a hollow part in the pipe wall of a synthetic resin pipe, in particular, by pressing a pressing member from the outer peripheral surface of a softened pipe, while crushing the hollow part. The present invention relates to a method for cutting a pipe in which a cavity is closed at the end of the pipe.

As a high-strength synthetic resin pipe, a pipe in which a large number of continuous cavities are formed in the pipe wall along the pipe axis (hereinafter referred to as a perforated pipe) is used. These perforated pipes are used in the same way as general resin pipes without holes, for example, to form a socket or as a collar joint pipe. Further, as these perforated pipes, a circular pipe 1 as shown in FIG. 1 or a pipe 2 with an oval cross section for a sewer pipe (hereinafter referred to as an oval pipe) as shown in FIG. 2 are being considered. These pipes can omit the volume of pipe forming material equivalent to the cavity 3, so when making pipes with the same wall thickness, it is possible to reduce the amount of resin used, and this extra If all or part of the resin is used as a molding material without saving, a large-walled pipe can be molded with the same amount of resin.

Incidentally, the cavities 3 of these perforated pipes open at the end faces of the pipes, and these openings are difficult to close even when the diameter of the pipes is expanded, and often remain. Therefore, when using these perforated pipes for normal insertion and joining, if the opening at the end of the insertion port is not properly sealed, the conveying fluid may enter the cavity from the cavity opening on the end surface of the insertion port. 3 and leaks from the socket end face. Furthermore, when these pipes are used as buried pipes, groundwater etc. may enter through the cavity opening formed on the opening end of the socket, enter the pipe through the opening on the socket end, and mix with the conveyed fluid. There is a risk of Furthermore, when these perforated pipes are used as exterior collar joints for buried pipes, these cavities 3 become areas where mud and filth accumulate. For this reason, it is recommended that the cavity 3 of the perforated pipe be closed at the end face of the pipe, and known means for closing these include inserting a plug into the opening of the cavity, or crushing the cavity.

However, these closure means require special plugging materials and bonding agents, and are inefficient because they take a long time to operate.

The present invention was made in view of these circumstances, and was made in an attempt to establish a more rational method of closing the pipe, and it was thought that it would be possible to cut the pipe and close it at the same time. In other words, conventional synthetic resin pipes have been cut using serrated cutters, but these cutters are constructed with a plurality of push-cutting blade members that move from the outer periphery of the pipe in the axial direction of the pipe, and these blades are Prior to applying the member, the cut portion of the pipe is heated and softened and held in a core shape, or is heated and softened while being held, and then the blade member is moved in the axial direction of the pipe to crush the pipe wall. At the same time, the cavity 3 of the cut portion is filled and closed, and the cutting is performed so as to leave a thin piece for separation or separation. Note that the cavity 3 formed in the pipe wall is not limited to a hole with a circular cross section as shown in FIG. 3 or a hole with a square cross section 3' as shown in FIG. However, the present invention can be applied regardless of the shape of these holes.

Hereinafter, the present invention will be explained in detail based on FIG. The present invention can be implemented in the same manner by changing the shape of the parts or changing the design depending on the purpose.

FIG. 5 is a pipe axial cross-sectional view when the present invention is applied to the perforated pipe 1 illustrated in FIG. However, it can be implemented in the same manner even if it is an enlarged diameter socket. The figure also illustrates a cutting device 4 composed of four pressing members 7, with the pressing members 7, 7 shown on the lower side showing the state in which the pipe has been cut, and the pressing members 7, 7 shown on the upper side showing the state before cutting the pipe. It is a schematic diagram. That is, the cutting device 4 includes a core mold 5 inserted into the inner cavity of the perforated pipe 1, a pressing member support device 6 arranged so as to leave a passage gap for the perforated pipe 1 on its outer periphery, and the support device. 6 and a pressing member 7 movably provided in a direction orthogonal to the pipe axis. That is, a plurality of pressing members 7 are formed so as to surround the inner peripheral surface of the pipe, and are moved toward the pipe axis by an appropriate propulsion device (not shown). The figure shows two slots 8, 8 formed in the pressing member 7.
It is shown that the support bolts 9, 9 are fixed to the support device 6 through them, and the pressing member 7 is slidably moved within the range of the slot 8. The propulsion device is a device that propels the individual pressing members 7 all at once, sequentially, or in an appropriate order, and as a propulsion means, an actuating cylinder may be used or a slit cam disk may be provided on the outer periphery of the support device 6. Appropriate means can be selected, such as rotating the pressing member 7 with a button, engaging a protrusion provided on the back side of the pressing member 7 with this slit, and moving the pressing member 7 all at once.

On the other hand, the cut portion of the perforated pipe 1 placed on the core mold 5 may be heated and softened prior to placement, or the core mold 5 may be provided with an appropriate heating means and the perforated pipe 1 may be heated and softened after the pipe is placed. good. This heating causes the pipe to reach a temperature above the plasticization start temperature at the cut portion. Next, when the pressing member 7 is moved toward the pipe axis by the propulsion device provided in the support device 6, the pressing member 7 moves the pipe wall from the outer periphery of the perforated pipe 1 to both sides, as shown in FIG. The hollow 3 of the perforated pipe 1 is pushed away, and the outer wall portion of the hollow pipe 1 is deformed to form a closed wall 3a, 3a, and the outer wall portion 1a,
This results in a curved surface as shown in 1a. As the pressing member 7 moves, not only the outer surface flesh of the cavity 3 but also the flesh of the pipe other than the part forming the cavity 3 flows and participates in the formation of the closing wall 3a, thereby reliably closing the cavity 3. can do. When the pressing member 7 is pressed against the outer surface of the core mold 5, the perforated pipe 1 is cut off, and the opening at the end of the perforated pipe can be closed at the same time as the cutting.

Although a portion of the pipe 1 will eventually be separated, in order to prevent the separated pieces from coming off all at once, a connecting thin piece 1 as shown in FIG.
0 may be formed. In such a case, the opening of the cutting portion is closed in the same manner as described above, but the pressing member 7 may be stopped just before it comes into contact with the core mold 5, and then the cutting may be performed in a conventional manner. In addition, in order to apply the pressing members 7 to the egg-shaped pipe 2 shown in FIG. 2, these pressing members 7 can be divided as shown in FIG. 9 and each pushed in the direction shown by the arrow. It can be cut while closing the opening.

In all of these embodiments, the opening of the perforated pipe was closed at the same time as the body was cut, or at the same time as the end edge was cut. The present invention can also be satisfied by closing the opening while cutting the edge of the opening at the same time as the socket is formed.
In particular, when the cutting pressing member is provided in an outer mold for socket molding, the supporting device 6 and the propulsion device for the pressing member can be replaced by a moving device for the outer mold. FIG. 10 is a cross-sectional view showing an example of the structure, in which a diameter-expanding core mold 11 is used as the core mold, and the end of the perforated pipe 1 to be inserted into the core mold 11 has already been heated and softened. Alternatively, it is softened by a heating device provided in the core mold 11 or by the heating temperature of the atmosphere.

On the other hand, a divided outer mold 12 for molding is disposed around the outer periphery of the core mold 11, and a pressing portion 13 protruding toward the core mold 11 is formed at the tip of the enlarged diameter molding portion of the outer mold 12. The pressing part 13 is formed in the same manner as the tip of the pressing member 7, and moves integrally with the outer mold 12 toward the core mold 11, and this movement simultaneously forms the outer periphery of the socket and the end of the socket. The edges are cut and the opening is closed. Although the figure shows the pressing part 13 formed integrally with the outer mold 12, if we consider forming the thin piece 10 as in the above example, the pressing part 1
It is also recommended that only 3 be formed separately and attached to the outer mold 12. If the opening is closed at the same time as cutting, the outer circumferential side of the end face will have a chamfered shape, but especially in the case of the open end face of the socket, the inner circumferential side will have a chamfered shape. Preferably, it is cut. FIG. 11 and FIG. 12 are cross-sectional explanatory views showing an example of an apparatus that takes these into consideration, and in particular forms a molding step portion 11a whose diameter is further expanded on the back side of the expanded diameter portion of the expanded core mold 11. At the same time, the connecting portion with the enlarged diameter portion is provided with an inclined surface 11b having a relatively high degree of inclination.
shall be. Further, the outer mold 14 for molding applied to this expanded core mold 11 is configured such that its inner end edge 14a abuts near the top of the inclined surface 11b. The perforated pipe 1 inserted into the core mold 11 is heated and softened as described above, and its tip is inserted until it reaches the circumferential surface of the diameter-expanding step 11a to perform diameter-expanding molding. Next, when the outer mold 14 is moved to the core mold 11 side and pressed against it, as shown in FIG. Separate into
At this time, the opening at the cut end of the perforated pipe 1 is closed by the same action as the pressing member 7 described above. In this example, since the inner edge 14a of the tip of the outer mold 14 contacts near the top of the inclined surface 11b, the amount of deformation of the pipe wall on the socket side is large, and the opening closing portion 15 of the cavity 3 is thick. It is formed. Furthermore, according to this cutting and press forming, a chamfered portion is formed on the inner peripheral side by the inclined surface 11b.

The above-mentioned opening closing by cutting was all performed by using a pressing member, a pressing part formed on the outer mold, or the inner edge of the sheared end, and by moving these toward the pipe axis. , another cutting device, such as a push-off roller, is rolled in the circumferential direction while being pressed against the circumferential surface of the heat-softened perforated pipe held in the core mold, or as shown schematically in FIG. A cutting band 18 is placed around the cut part of the perforated pipe 1 which is held at the pipe 17 and softened by heating, and one end of the band 18 is moored to the stopper 19, and the other end is fastened to the positively moving member to tighten the band 18. Ba,
The band 18 can separate the perforated pipe 1 and close the cavity at the end surface of the pipe in the same manner as the pressing member. 20 indicates an operating cylinder.

As described above, the present invention can close the cavity opening at the cut end at the same time as cutting the perforated pipe, so not only does a special closing plug member not be required, the working time is very short, and the cavity opening can be closed reliably. This can streamline the manufacturing and processing process of perforated pipes.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory cross-sectional views of a perforated pipe, Figures 3 and 4 are partial cross-sectional views showing examples of cavities formed in the pipe meat, and Figure 5 is an example of the present invention. FIG. 6 is a partially enlarged sectional view in the direction of arrows along the cutting line - of FIG. 5, FIG. 7 is an explanatory diagram of the operation of FIG. 6, and FIG. An explanatory sectional view showing an example, FIG. 9 is an explanatory view of a pressing member applied to an egg-shaped pipe, FIG.
FIG. 1 is an explanatory sectional view showing another embodiment of the present invention, FIG. 12 is an explanatory diagram of the operation of FIG. 11, and FIG. 13 is an explanatory diagram showing another embodiment of the present invention. 1...Circular pipe, 2...Egg-shaped pipe, 3...
Cavity, 4... Cutting device, 5... Core mold, 6... Support device, 7... Pressing member, 10... Thin piece, 11...
Expanded diameter core mold, 12... Outer mold, 13... Pressing part, 14
...External mold, 15...Thick-walled closed part, 16...Separation,
17...core type, 18...band, 19...stopper, 20...operating cylinder.

Claims (1)

[Claims] 1 A method of closing and cutting the hollow part of a synthetic resin pipe in which a large number of continuous cavities are formed along the pipe axis in the pipe wall, in which the resin pipe that has been softened by heating is held in a core shape, and the resin pipe is A cavity in the pipe wall of a synthetic resin pipe, characterized in that a pressing member is pressed in a direction substantially perpendicular to the pipe axis to crush and close a continuous cavity of the pipe while cutting it off or separating it to form a flake. How to cut off the part.