JPS604748Y2 - Circular die for two-layer plastic extrusion - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a circular die that facilitates adjustment of the thickness of each of the two layers when a steel pipe or the like is coated with two layers of plastic or a two-layer plastic pipe is manufactured.

It is well known that a circular die for two-layer extrusion is used to coat the outer peripheral surface of a steel pipe with two layers of plastic or to form a two-layer plastic pipe.

FIG. 1 shows an example of this, and this circular die is composed of an outer die 1, intermediate dies 2, 2a, and an inner die 3, which extend the inner circumferential direction of the die body.
Two resin reservoirs 4, 4a and □Resin derivation term 9fu 1 part 5
, 5a and these resin lead-out slit parts 5, 5a are 1
An extruded resin lip portion 6 is formed.

The two types of molten plastic resin are then transferred to the intermediate die 2.
, each person enters from the lower floor provided at 2a, 7a,
After going around the entire circumference in the resin reservoirs 4 and 4a, the slit part 5.5
a, and is coated on the outer surface of the copper body P from the lip part 6,
Or it can be molded as a plastic tube.

In this case, it is desirable that the plastic be extruded uniformly in the circumferential direction, with no variation in film thickness or tube thickness.

For this reason, in the past, the lining film thickness or tube thickness was adjusted using the adjustment bolt 8. In other words, this work was performed using the intermediate die 2a.
The outer die 1 is moved in the radial direction by pushing and pulling an adjustment bolt 8 inserted into the outer die 1.

However, in such a conventional die structure, since the intermediate die 2 cannot be moved, only the slit portion 5 can be adjusted.
The limit is the amount of play in the vertical direction in the hole forming hole 9a.
If , it becomes difficult to assemble and adjust.

In addition, such adjustment means is effective when the outer die 1 and the intermediate gouer 2 in the slit portion 5 maintain a perfect circle state and are simply misaligned with each other, but in reality, each gou As the gou is heated to a high temperature or returned to room temperature, distortion occurs in the gou, and the cross-sectional shapes of the outer die 1 and the middle gou 2 deform into approximately elliptical shapes.When this happens, conventional adjustment means are unable to adjust the film thickness or tube thickness. Adjustment becomes difficult or impossible.

Furthermore, adjustment of the slit portion 5 is conventionally done by loosening the fixing bolt 9.
Since the procedure involves moving the adjustment bolt 8, this work cannot be done during lining.

Furthermore, even if the outer die 1 can be fixed to the intermediate die 2a without using the fixing bolt 9, since the direction of the force applied when adjusting the adjusting bolt 8 is perpendicular to the tube axis, the intermediate die 2a and The intermediate stand 2 and inner die 3 that are connected to the goo may move slightly in the direction perpendicular to the tube axis due to the action of this force, resulting in uneven circumferential film thickness or accidents where part of the goo body comes into contact with the tube body P. This is difficult to do during lining, and the actual situation is that the line has to be stopped each time it is necessary to adjust the film thickness.

The present invention was proposed in order to solve these conventional disadvantages, and it is possible to easily and reliably perform the above-mentioned guide adjustment even during line operation, and to eliminate circumferential variations in plastic film thickness or tube thickness. The present invention aims to provide a new circular gouer for extruding two-layer plastics that can be made uniform.

Next, an embodiment of the present invention will be explained with reference to FIGS. 2 and 3. First, in FIG. ,
The both side outer guides 10 and 11 and the intermediate outer die 12 are each fixed by a plurality of fixing bolts 14 and 15,
Further, the side outer die 11 and the inner die 13 are similarly fixed by a plurality of fixing bolts 16.

There are two resin reservoirs 17.18 and 17.1 inside the goo body made up of these divided gouies.
Resin lead-out slit parts 19 and 2 extended from 8 respectively.
0 and the lip portion 21, and further a tube through hole X is formed.

The slit portions 19.20 for leading out the resin are formed perpendicularly to the axis of the pipe P to be coated or molded, and each slit portion 19.20 communicates with the lip portion 21. It is.

Further, adjustment rings 2 are provided on the inner surfaces of the outer dies 10.11 on both sides of the resin lead-out slit portion 19.20, respectively.
2, 22a are fitted so as to be movable in the facing direction of the intermediate outer die 12, and from the outside of the gouer body A, pull bolts 23, 23a and a presser are inserted in parallel to the tube axis direction from the outside to the adjustment rings 22, 22a. Adjustment bolts each having a set of bolts 24 and 24a are inserted.

These pull bolts 23, 23a and holding bolts 24, 24
In this embodiment, as shown in FIG.
3 or 23a, and a plurality of these are attached as a set in the circumferential direction on both outer sides of the goo body A.

Figure 4 shows the tension bolt 23.23a and the holding bolt 2.
4.24a, the minus side pull bolt 23 and presser bolt 24 are shown in detail as an example, where A is the pull bolt 23 and B is the presser bolt 24.

That is, the tension bolt 23 is inserted into the through hole 2 provided in the outer die 10.
5, and its tip is screwed into a threaded portion 26 formed on the adjustment ring 22.

Further, the holding bolt 24 is screwed into a screw hole 27 similarly formed in the outer die 10, and the tip of the holding bolt 24 is inserted into the adjusting ring 22.
The back surface 28 of the device can be pressed.

This structure is the same for the pull bolt 23a and press bolt 24a on the other side, but in this embodiment, these pull bolt 23a and press bolt 24a are made to penetrate from the outside of the inner die 13 due to the structure of the goo body.

In addition, in the figure, 29 and 30 are the resin reservoirs 17, respectively.
．． This is the entrance leading to 18.

The above is merely an example of the present invention, and the arrangement and structure of the tension bolts 23.23a and holding bolts 24, 24a, the shapes of the inner die 13 and the outer dies 10, 11.12, etc. are as shown in the drawings. It is not limited to things.

When the pipe body P is double coated with plastic or a double pipe is manufactured according to the present invention, first, each inlet 2 is
The two types of molten plastics entering from 9.30 pass through their respective resin reservoirs 17.18 and rotate in the circumferential direction,
The resin is extruded from one lip part 21 through the slit parts 19 and 20 for leading out the resin, and is coated on the outer circumferential surface of the tubular body P or formed into a pipe.

In this case, the adjustment of the membrane thickness or pipe thickness is performed using the tension bolt 23,
23a and the holding bolts 24, 24a adjust the adjustment ring 2.
2, 22a in the width direction of each resin lead-out slit portion 19, 20 and adjust the clearance thereof.

That is, first, when narrowing the width of the resin lead-out slit portion 19.20, the tension bolts 23, 23a are loosened in advance, and the outer surface 10a or 1 of the outer die 10 or the inner die 13 is narrowed.
3a and each tension bolt part, and then turn the holding bolts 24, 24a and push in the adjustment rings 22, 22a.
t22a moves in the direction of the intermediate outer die 12 by the amount of the clearance, and the resin lead-out slit portions 19 and 20 are narrowed.

In addition, when widening this resin lead-out slit part 19.20, after loosening the holding bolts 24, 24a, turn the pull bolt 23.23a and adjust the adjustment ring 22.22a on the inner surface of the outer die 10.11 on both sides. direction, and then turn the holding bolt 24.24a to tighten the adjustment ring 2.
2, 22a.

The combination of these three poles 23, 24, and 23 can prevent the generation of convex portions of the ring 22 that are formed on both sides of the pressing point when the adjusting ring 22 is pressed with one bolt. , it is possible to easily and completely uniformize the film thickness in the circumferential direction.

According to the present invention as explained above, even if the cross-sectional shape of each outer die or inner die is deformed due to heat or the like, each resin lead-out slit portion 19 can be fixed without removing the fixing bolts 14, 15, 16. , 20 can be easily and reliably adjusted, making it possible to equalize the film thickness and pipe thickness in each layer temperature direction, and furthermore, the direction of the force applied when adjusting the bolt is parallel to the pipe axis. Because of this, the film thickness does not become uneven in the circumferential direction, the goo body does not touch the pipe body, and the film thickness can be adjusted even during lining, etc., and has various excellent advantages. It is.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a conventional circular die for extruding two layers of plastic, Fig. 2 is a sectional view of a circular die for extruding two layers of plastic showing an embodiment of the present invention, and Fig. 3 is a sectional view of a circular die for extruding two layers of plastic. FIG. 4A is an enlarged cross-sectional view showing the tension bolt structure of the present invention, and FIG. 4A is an enlarged cross-sectional view showing the holding bolt structure. In the figure, 10.11 is an outer guide on both sides, 12 is an outer guide in the middle, 13 is an inner guide, 14, 15.16 is a fixing bolt, 17
．． 18 is a resin reservoir, 19.20 is a slit portion for leading out the resin, 21 is a lip portion, 22° 22a is an adjustment ring, 23,
23a is a pull bolt, 24.24a is a presser bolt, 25
26 is a through hole, 26 is a threaded portion, 27 is a threaded hole, 28 is a back surface, 29.
30 is an inlet, A is a goo body, and P is a pipe body.

Claims (1)

[Scope of utility model registration request] Two resin reservoirs, two resin lead-out slits, a first resin extrusion lip, and a tube through hole are formed in the circumferential direction by one inner guide, outer dies on both sides, and outer die at the middle, and each of the above-mentioned A resin lead-out slit part is formed perpendicularly to the tube axis of the pipe body to be coated, and an adjustment ring is installed at the corresponding part of the resin lead-out slit part in each of the outer dies on both sides, respectively, so as to align the resin lead-out slit part with the tube axis. Adjustment bolts are fitted so as to be movable in parallel to the direction of the tube, with a holding bolt in the center and tension bolts near both sides of the holding bolt, and an adjustment bolt made up of these bolts is inserted parallel to the tube axis direction from the outside of the outer die to the adjustment ring. A circular die for extruding two-layer plastics, characterized in that a plurality of sets of these adjusting bolts are provided in the circumferential direction of the adjusting ring.