JPH0818364B2 - Synthetic resin pipe manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is provided with a spiral reinforcing strip on the outer circumference of a pipe wall such as a corrugated pipe used by being buried in the ground, and has a smooth inner wall surface. The present invention relates to an apparatus for manufacturing a synthetic resin pipe as described above.

(Prior Art) Conventionally, as a synthetic resin pipe manufacturing apparatus of this type, for example, several molding shafts are arranged on a virtual cylinder, and one end portion of the molding shaft is cantilevered on a base. It has a structure in which it is interlockingly connected to an appropriate drive means, and this forming shaft is slightly inclined with respect to the axis of the virtual cylinder. A strip material having a letter-shaped portion and a pair of plate-shaped portions which will be the inner wall of the pipe after molding is extruded from the forming die, and the strip material is wound around the spiral shaft so as to extend between the forming shafts. , The one side edge of the strip material and the adjacent other side edge are sequentially polymer-welded, and in this state, the respective molding shafts are driven in unison, whereby a spiral reinforcement is provided on the outer circumference of the pipe wall. Synthetic resin pipes are sequentially molded and sent out from the free end side of the molding shaft. .

On the other hand, Japanese Unexamined Patent Publication No. 51-37969 also discloses a manufacturing apparatus for manufacturing a synthetic resin pipe while molding a spiral reinforcing strip by using a flexible molding die.

The thing described in the above-mentioned publication is such that a thermoplastic synthetic resin sheet is superposed on the inner surface side of a core die and is wound around a molding shaft in a spiral shape, and a semi-molten synthetic resin strip material is provided on the core die. By winding and solidifying the resin sheet by cooling and then removing the integrated core die and resin sheet, a synthetic resin tube having a hollow inside of the reinforcing strip is formed.

(Problems to be Solved by the Invention) However, in any of the above cases, there were the following problems. That is, when the former manufacturing apparatus is used, a strip material having a U-shaped cross-section portion which becomes a spiral reinforcing strip after molding is preformed by a forming die, and the strip material is semi-molten in the semi-molten state. Since it is wound at a high speed, the reinforcing strip inevitably loses its shape during winding. Particularly, in the case of a reinforcing strip having a hollow interior, the shape of the reinforcing strip is severely deformed, and therefore it has been extremely difficult to manufacture a synthetic resin pipe having a highly precise and orderly shape.

On the other hand, when using the latter manufacturing apparatus, the shape of the reinforcing strip is formed in an orderly shape by the shaping core die, the shape collapse can be eliminated, and the shape of the core die can be changed as appropriate. The shape of can be set arbitrarily, and it can also be applied to a device that can change the diameter and pitch.However, when molding a flat inner wall of the pipe, the inner layer pipe is first molded and then the inner layer is It is impossible to form the outer layer tube on the tube. In addition, in order to forcibly form using this manufacturing device, the strip material for forming the inner layer tube is wound around the inner surface of the outer layer tube after completion and welded, but at this time, the outer layer tube has already been cooled and solidified. Therefore, there is a high risk that the joint portion will separate due to contraction during cooling of the inner layer pipe after joining.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is efficient and continuous in the production of a synthetic resin pipe in which the shape of the reinforcing strip is orderly and the pipe wall inner surface is flat. The object is to provide a device that can be used.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a synthetic resin pipe in which an inner peripheral surface is formed into a flat wall surface and a spiral reinforcing strip is provided on the wall surface. Which is a device for manufacturing a flat material by winding a semi-molten strip material in a spiral shape and superimposing the other side portion of the succeeding strip material on one side portion of the preceding strip material. A molding shaft for molding the wall surface is provided, and an endless molding core die is spirally wound around the molding shaft so that the core die can be circulated, and the semi-molten strip material is formed on the molding core die. The spiral reinforcing strip is formed by winding so as to cover the central portion, and further,
A reinforcing core to be molded on the molding core is provided with a cutter that forms a continuous spiral groove on the reinforcing bar at a suitable position in the spiral advance direction, and the molding core die inside the reinforcing bar is extracted through this groove. It is possible to dispose, outside the molding shaft, extrusion molding means for the band-shaped material that supplies the semi-molten band-shaped material to the reinforcing strips after the molding core die is removed to close the kerf. Have a structure.

(Operation) According to the above configuration, the semi-molten strip material wound on the forming shaft has one side portion of the preceding strip material and the other side portion of the succeeding strip material on the forming shaft. Formed on a flat wall surface by polymerizing, and molded accurately at the same time as the flat wall surface on a reinforcing strip having the same cross-sectional shape as the molding core die by the central portion of the strip material covering the molding core die. By setting this core type to any shape,
It is also possible to mold the above-mentioned reinforcing strips having a desired shape, especially one having an inverted trapezoidal cross section or a closed cross section, which has been difficult to form in the past. Further, since the reinforcing strip is shaped by winding the core die around the forming shaft, it can be applied to a forming apparatus in which the pipe diameter and the spiral pitch of the reinforcing strip can be changed.

(Example) Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

The apparatus of this embodiment shown in FIGS. 1 to 4 is applied to a manufacturing apparatus of a synthetic resin pipe in which the pipe diameter and the spiral pitch of the reinforcing strip can be changed, and (11) in the drawings shows the main body. A box (11) is provided with a support shaft (13) protruding from the inside of the box (11) through the face plate (12), and a number along the virtual cylindrical surface centered on the support shaft (13). A book forming shaft (14) is arranged.

Each of the molding shafts (14) is composed of a short shaft (15) and a long shaft (16) connected to each other through a universal joint (17). Minor axis (1
By bending the major axis (16) slightly with respect to 5), the major axis (16) is slightly inclined with respect to the support shaft (13). Also, each of the short axes (15) is a main body box (11).
In the inside, it is interlockingly connected to a drive means (18) through a connecting shaft (19) capable of expanding and contracting and bending, and this drive means (1
By 8), each forming shaft (14) is driven simultaneously in the same direction.

Further, the support shaft (13) is fitted with top members (20) (21) (22) which are movable on the shaft, and the top members (20) (21) (22) are attached to the top members (20) (21) (22). The short shaft (15) and the long shaft (16) are pivotally attached to each other via connecting rods (23) (24) (25) so that the forming shaft (14) is supported on the support shaft (13). It is designed to support the expansion and contraction of the diameter. Each of the top members (20) (21) (22) is configured to move in the axial direction by a rotating operation of an actuating shaft (26) arranged along the support shaft (13). The side member (22) is a receiving member (2) that is fitted onto the support shaft (13) so as to be movable only in the axial direction.
2 ') is spline-fitted to the top member (22)
By changing the circumferential position on the receiving member (22 '),
The inclination angle of each forming shaft (14) with respect to the support shaft (13) is changed.

In the above-mentioned embodiment, a plurality of molding shafts (14) are used in order to make the diameter of the synthetic resin pipe to be molded and the spiral pitch of the reinforcing strip variable, and the structure is as described above. If the pipe diameter and spiral pitch are not variable in,
A general molding shaft may be used. The general forming shaft referred to here is a conventionally known one, and is formed by using, for example, a single forming main shaft and supporting a plurality of roller shafts in an inclined shape by a cylindrical retainer on the outer periphery thereof. It may have any structure such as a shaft.

As the strip material (1) wound around the molding shafts (14), for example, a synthetic polyolefin resin such as polyethylene resin or polypropylene resin, or vinyl chloride resin is used. The molding die (28) of the extrusion molding means (27) is extruded into a desired shape, for example, a flat plate shape, and is supplied to each molding shaft (14) side in a semi-molten state to form each molding. Wind it in a spiral shape so that it extends over the shaft (14). Then, as shown in FIG. 5.6, a section (1a) having a U-shaped cross section and a section (1) having a U-shaped section (1
a) Plate-shaped long side part (1b) extending from one lateral lower end
And the plate-shaped short side portion (1c) extending from the lower end portion on the other side is formed in series. The strip material (1) is usually made entirely of hard synthetic resin, but the U-shaped portion (1a) and the short side portion (1c) are made rigid, and the long side portion (1b) is made. The soft synthetic resin may be used, or the whole may be formed of the soft synthetic resin.

On the other hand, a flexible endless molding core die (29) is wound in advance in a spiral shape so as to extend between the molding shafts (14).

The molding core die (29) is made of, for example, a single flexible belt material having substantially the same cross-sectional shape as the U-shaped portion (1a) molded from the strip material (1). Is wound in a spiral shape so as to extend over each of the molding shafts (14), and the molding shaft (14) is separated from the winding end of the molding shaft (14) and extends in a slack form to wind the molding shaft (14). It is configured so as to return to the starting end and travel in a spiral shape on the forming shaft (14). The top of the core die (29) has a V-shaped groove (30) that allows a cutter (34) to be described later to enter.
The guide material (31) is provided at the starting end where the strip material (1) enters when winding as shown in FIG. 4 so as to regulate the entry position of the core die (29). I have to.

Further, similar to the molding core die (29) described above, the core die (2) extending between the molding shafts (14) and spirally wound (2).
An endless presser die (32) is spirally wound so as to be located between 9). The pressing die (32) is for pressing the strip material (1) between the spiral core dies (29), has flexibility like the core die (29), and has a winding end. The presser die (32) extends to the start end and connects both ends to form an endless shape. This presser die (32) is formed from the core material (29) after the strip material (1) is formed on it. It is something to wrap around. In the figure, (33) is a guide roller for guiding the presser die (32) to enter.

Thus, as described above, by using the molding core die (29) and the pressing die (32) on each molding shaft (14), the strip material (1) is spirally wound to form the pipe wall (A). A synthetic resin pipe having a flat inner surface and a spiral reinforcing strip (B) on the outer periphery of the pipe wall (A) is molded, and then a cut groove (C) is formed on the top of the reinforcing strip (B).
Is formed so as to close the kerf (C) continuously, and the cutter (34) is arranged in front of the synthetic resin pipe in the spiral advancing direction and the cutter (3) is formed.
4) A molding die (36) of the extrusion molding means (35) is arranged in front of the spiral advancing direction, and a semi-molten band material (2) is provided at the top of the reinforcing strip (B). The kerf (C) is closed. The cut groove (C) formed in the reinforcing strip (B) may be at a portion other than the top, for example, a side surface. Further, as the strip-shaped material (2), a hard synthetic resin of the same quality as the ordinary strip material (1) is used.
Instead of this, a soft synthetic resin such as a soft polyethylene resin is used as the strip material (1), and a hard synthetic resin such as a hard polyethylene resin is used as the belt-shaped material (2). You may be able to raise it.

Next, the operation of the above-described manufacturing apparatus of the present invention will be described.

First, the semi-molten strip material (1) extruded and supplied in a flat plate shape from the die (28) of the extrusion molding means (27) is wound around the respective molding shafts (14) that are driven and rotated in unison. . At this time, since the molding core die (29) is wound around each of the molding shafts (14) in advance, the strip material (1) forms the core die (29) and has a U-shaped portion (1a). ), The long side portion (1b) and the short side portion (1c) are formed, and since the forming shafts (14) are slightly inclined, the strip material (1 ) Is wrapped in a spiral,
The U-shaped portion (1a) and the short side portion (1c) of the succeeding strip material (1) are integrally welded on the long side portion (1b) of the preceding strip material (1) so as to be integrally welded to each other. A synthetic resin pipe having a flat inner surface of (A) and a spiral reinforcement (B) is formed on the outer periphery thereof in order. In particular, the U-shaped portion (1a) forms a spiral reinforcing strip (B), and the long and short side portions (1b) and (1c) that overlap with each other form the pipe wall (A). Thus, the inner surface of this tube wall (A) becomes flat.

On the other hand, the pressing die (32) is supplied to the outer circumference between the reinforcing strips (B) of the synthetic resin pipe which is sequentially molded as described above, and thereby the long and short side portions (1b) (1c) which are overlapped with each other.
Is pressure-bonded to enhance the polymerization state thereof and to perform the welding more reliably.

Then, a cutter (34) is pierced at the top of the reinforcing strip (B) of the synthetic resin pipe continuously molded on each of the molding shafts (14), and a cut groove (C) is formed at the top of the reinforcing strip (B). ) Is continuously formed, the core die (29) is extracted from the reinforcing strip (B) through the cut groove (C) and returned to the winding start end portion. At this time, the cutter (34) is such that the cutting edge projects into the V-shaped groove (30) of the core die (29), and the cutting can be performed completely. The reinforcing strip (B) is cooled to such an extent that it does not lose its shape when the core die (29) is pulled out.

After that, the semi-molten band material (2) is supplied from the die (36) of the extrusion molding means (35) to the top of the reinforcement (B), and the cut groove (C) at the top of the reinforcement strip (B) is provided. Will be closed. The strip-shaped material (2) is made of the same synthetic resin as the strip material (1) and is formed into a plate shape having the same width as the top portion of the reinforcing strip (B). Further, the kerf (C) expands when the core die (29) is pulled out, and the kerf is not completely closed after the bleeding, but is in a slightly opened state. The strip-shaped material (2) partially enters and solidifies, and plays a role of a binder for firmly joining the tops of the reinforcing strips (B) divided by the kerfs (C).

In the synthetic resin pipe molded as described above, the joint boundaries of the strip material (1) and the band-shaped material (2) are clearly shown in the illustrated example, but in reality, the same material is heat-welded. Are integrated.

Thus, as shown in FIG. 5, the synthetic resin pipe manufactured by the apparatus of this embodiment has a long side portion (1b) and a short side where the pipe walls (A) overlap each other and are continuous in the pipe axial direction. Part (1
c), the inner surface of which is made flat to realize soft flexibility and low flow resistance in the pipe, and the spiral reinforcing strip (B) has a U-shaped portion ( 1a)
And can provide high crush resistance.

It should be noted that the present invention is not limited to the structure as described in the above-mentioned embodiments, but can be appropriately modified and improved in design.

For example, in the above-mentioned embodiment, the strip material (1) is formed into a flat plate shape, which is then wound around a semi-molten core core (29) to be formed. Shaped part (1a)
The strip material (1) having the long and short sides (1b) (1c) is previously formed by the forming die (28), and the thus formed strip material (1) is formed into the forming shaft (14). It may be supplied on the upper side, and as shown in FIG. 7, a thin portion (1d) is formed on the top of the U-shaped portion (1a) so that the subsequent cut groove (C) can be easily formed. You may Further, in addition to the single U-shaped portion (a) provided as the strip material (1), two pieces may be formed as shown in FIG. 8 or three or more pieces may be formed to form each piece. It may be allowed to polymerize at times.

Further, the strip-shaped material (2) may be inserted into the cut groove (C) at the top of the reinforcing strip (B) as in the embodiment, but it should not enter as shown in FIGS. 9 to 12. Alternatively, as shown in FIG. 10, the width of the band-shaped material (2) is set to be slightly larger than the width of the kerf (C), and the so-called kerf (C) is simply closed. May be again
As shown in Fig. 11, the shape of the band-shaped material (2) is reinforced (B).
May be entirely covered, and in this case, since the strip-shaped material (2) is wider than the width of the top surface of the reinforcing strip (B), the strip-shaped material (2) is placed along the side surface of the reinforcing strip (B). It is also possible to cover between the top surfaces of the adjacent reinforcing strips (B) and (B) without any need. Furthermore, the kerf (C) formed at the top of the reinforcing strip (B) is a blade of the cutter (34). The thickness may be made extremely thin so that the groove width cannot be formed as shown in FIG.

Further, the molding core die (29) and the pressing die (32) in the above-mentioned examples can be made of hard rubber, synthetic resin, leather, etc., in addition to being formed of a belt material, and further, aluminum, aluminum alloy, etc. It can also be formed of the metal. In this case, as shown in FIG. 13, the core die (29) or the press die (32) may be divided into a large number of blocks, and the blocks may be connected by a wire (37) so as to be bendable. At this time, a thin belt material (38) may be attached to the inner surface. Further, the shape thereof may be, for example, a semicircular shape, a square shape, or a round cross section, in addition to the trapezoidal cross section.

FIG. 14 shows an example of a synthetic resin pipe having a reinforcing strip (B) having a semicircular cross section. The parts corresponding to the respective parts of the above-mentioned embodiment are designated by the same reference numerals and the description thereof will be omitted. .

Further, according to the present invention, as shown in FIG. 15 and FIG. 16, a forming core die (29) is inserted through a forming means (27) into a strip material (1).
Alternatively, the reinforcing strip (B) may have a closed cross section as shown in FIG.

Further, the present invention may be configured as shown in FIGS. 18 to 20. The basic structure of this embodiment is similar to that of the previous embodiment, and the description of the same parts will be omitted and only the parts having different structures will be described.

First, the molding core die (29) is made of, for example, an endless flexible belt material having substantially the same sectional shape as the U-shaped portion (1a) of the strip material (1). Axis (14)
While preliminarily spirally winding so as to straddle the upper part, while loosening the portion from the winding start end to the winding end below the molding shaft (14), at the position below the molding shaft (14), Multiple auxiliary shafts with the same structure (39)
Is provided, and the loosened core die (29) is wound around the outer periphery of the auxiliary shaft (39) so that the spiral direction thereof is opposite to that on the forming shaft (14).

Specifically, a support shaft (40) is provided so as to project from the inside of the main body box (11) through the face plate (12), and the auxiliary shaft is provided along a virtual cylindrical surface centered on the support shaft (40). (39) is arranged, and the top members (41) and (42) are inserted onto the support shaft (40) so as to be movable in the axial direction, and the auxiliary shafts are attached to the respective top members (41) (42). Connect the (39) rod (4
3) The auxiliary shafts (39) are supported on the support shaft (40) in such a manner that they can be expanded and contracted by pivotally pivoting via the (44). Each of the top members (41) (42) is configured to move in the axial direction by a rotating operation of an operating shaft (45) arranged along the support shaft (40). (42) is spline-fitted to the receiving member (42 ') that is fitted onto the support shaft (40) so as to be movable only in the axial direction.
By changing the circumferential position of the top member (42) on the receiving member (42 '), the inclination angle of each auxiliary shaft (39) with respect to the support shaft (40) can be changed.

Then, the slack core (29) is spirally wound so as to extend between the auxiliary shafts (39) configured as described above. At this time, the winding spiral direction on the auxiliary shaft (39) is opposite to the winding spiral direction on the forming shaft (14) of the core mold (29). 29)
Even if it is endless in advance, it can be spirally wound without being twisted on the molding shaft (14).
In this embodiment, when the auxiliary shafts (39) are not configured to be capable of expanding and contracting in diameter, the auxiliary shafts (39) can be freely moved toward and away from the forming shaft (14). The slack of the molding core die (29) due to the change in the diameter may be absorbed by separating the auxiliary shafts (39) from each other.

Further, in the above-mentioned embodiment, as shown in FIG. 19, one or several ring-shaped presser molds (32) are used, which are used to reinforce the synthetic resin pipe on the molding shaft (14). B) The holding die (32) may be mounted very easily by straddling between the spiral grooves. At this time, the weight (4
Hang a sliding body (46) such as a pulley with 7),
Long and short sides (1a) (1b) of the strip material (1) that overlap with each other
Crimping and prevention of deformation of the U-shaped portion (1a) may be performed. In this case, the weight (47) can be replaced and the crimping load of the long and short side portions (1a) (1b) May be adjustable.

(Effects of the Invention) As described above, according to the present invention, there is provided a device for manufacturing a synthetic resin pipe having an inner peripheral surface formed on a flat wall surface and having a spiral reinforcing strip on the wall surface. A semi-molten strip material is spirally wound to form a flat shaft by forming the flat wall surface by superposing one side portion of the preceding strip material and the other side portion of the following strip material. At the same time, an endless molding core die is spirally wound around the molding shaft so that the core die can be circulated, and the center portion of the semi-molten strip material is covered on the molding core die. Since the spiral reinforcing strip is formed by turning, the semi-melted strip material supplied to the forming shaft is spirally wound around the forming shaft by the forming core die. It is possible to form a reinforcing strip with the same cross-sectional shape as the core type with high precision and on the forming shaft. The flat wall surface can be integrally formed simultaneously with the above-mentioned reinforcing strip by superposing the opposite side portions of the strip material with each other. Therefore, a synthetic wall having a flat inner wall and a reinforcing strip on the pipe wall The resin pipe can be efficiently and continuously manufactured.

Further, by setting the molding core die to an arbitrary shape, it is possible to mold a desired reinforcing strip shape, in particular, a shape having an inverted trapezoidal cross section or a closed cross section, which has been difficult to be conventionally molded. Further, since the reinforcing strip is shaped or molded by winding the core die around a molding shaft, a plurality of molding shafts are used to make their radial positions variable, and synthetic resins having different diameters and pitches. It can be applied to a molding device capable of molding a tube. Further, a cutter for forming a kerf into a continuous spiral ridge is arranged on the reinforcing strip at a proper position in the spiral advance direction of the reinforcing strip to be molded on the core for molding, and the core die for molding in the reinforced strip through the slit. The strip-shaped material can be pulled out, and a strip-shaped material extruding means for supplying the semi-molten band-shaped material to the reinforcing strips after the molding core die is removed to close the kerf is provided outside the molding shaft. Therefore, it is possible to smoothly remove the molding core die from the cut groove of the reinforcing strip cut by the cutter and circulate it again to the side of supplying the strip material to the forming shaft. The kerf formed can be continuously closed by the semi-molten band material from the extrusion molding means, and a reinforcing strip excellent in strength can be formed.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a plan view thereof, FIG. 2 is a vertical sectional front view in which the same portions are omitted, and FIG. 3 is a partially cutaway plan view in which the same portions are omitted. The figure shows the side view,
FIG. 5 is an explanatory view of the forming process, FIG. 6 is a longitudinal sectional view of a strip material formed on a forming shaft, FIGS. 7 and 8 are longitudinal sectional views of strip materials having different shapes, and FIGS. 9 to 12. Are sectional views showing different forms of the band-shaped material, FIG. 13 is a partial perspective view showing a different embodiment of the molding core die, FIG. 14 is another explanatory drawing of the molding process, and FIG. 15 is a second embodiment. 16 is a partially omitted plan view, FIG. 16 is a side view thereof, FIG. 17 is an explanatory view of the same molding process, FIG. 18 is a partially cutaway plan view showing a third embodiment, and FIG. 19 shows a part thereof. The omitted vertical sectional front view and FIG. 20 are the same side views. (1) …… Article material, (2) …… Strip material, (14) …… Molding shaft, (29) …… Molding core die, (32) …… Presser die, (18) …… Cutter, ( A) ... pipe wall, (B) ... reinforcing strip, (C) ... cut groove,

Claims (2)

[Claims] 1. An apparatus for producing a synthetic resin pipe having an inner peripheral surface formed on a flat wall surface and having a spiral reinforcing strip on the wall surface, wherein a semi-molten strip material is spirally wound. It is equipped with a forming shaft for forming the above flat wall surface by superimposing the other side part of the succeeding strip material on the one side part of the preceding strip material which is rotated to form an endless shape on the forming shaft. The spiral reinforcing strip is wound by spirally winding the molding core of (1) so that the core of the semi-molten material is wound on the molding core to cover the central part of the strip. It is configured to mold, and further, a cutter that forms a continuous spiral groove is formed in the reinforcing strip at a suitable position in the spiral advance direction of the reinforcing strip that is molded on the molding core die, and the reinforcing strip is reinforced through this slit. It is possible to pull out the molding core die inside the strip, and remove the molding core die outside the molding shaft. It supplies the strip material of the semi-molten state are arranged extrusion means of the strip material to close the cut grooves apparatus for producing synthetic resin tubes, wherein the reinforcing strip after. 2. An endless holding die is spirally wound so as to be cyclically movable between the molding core molds which are spirally wound so as to be cyclically movable on a molding shaft. The synthetic resin pipe manufacturing apparatus described.