JP2608769B2 - Synthetic resin spiral tube manufacturing method and bending molding apparatus used in this method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a synthetic resin pipe having a spiral ridge formed on an outer peripheral surface thereof, such as a corrugated pipe buried underground. And an apparatus for bending and forming a belt-shaped synthetic resin material used in this method.

[Conventional technology]

Conventionally, in order to manufacture this kind of synthetic resin pipe, for example, several rotating shafts for molding are arranged on a temporary cylinder, and one end of the rotating shaft for molding is cantilevered on a base. While hanging
Each rotating shaft is connected to a driving means, and the forming rotating shaft is slightly inclined in the circumferential direction with respect to the axis of the temporary cylinder, and at the time of tube forming, a hollow reinforcing strip is formed as a spiral reinforcing strip after forming. A band-shaped molding material in a semi-molten state having a ridge portion and a plate-shaped portion serving as an inner wall of the tube is extruded from a molding die, and the band-shaped molding material is spirally wound so as to extend between the respective molding shafts. At the time of winding, one side edge of the molding material and the other side edge adjacent thereto are sequentially polymer-welded to continuously drive a molding shaft while rotating the molding shaft to continuously mold a synthetic resin tube in which a hollow ridge is spirally provided on the outer peripheral surface. The method of going is adopted.

[Problems to be Solved by the Invention]

However, according to this method, a band-shaped molding material in a semi-molten state having a hollow ridge portion serving as a spiral reinforcing strip and a plate-shaped portion serving as an inner wall of a tube is extruded beforehand by a molding die, and the molding material is extruded. Since it is wound around the rotary shaft at a high speed in a spiral shape, the band-shaped molding material in the semi-molten state may be deformed by pulling or the like, and the shape may be lost during winding. The shape, thickness, etc. of the formed spiral hollow ridges are not uniform.

Furthermore, since the molding material in a semi-molten state is formed by sequentially polymerizing and welding one side edge and the adjacent side edge on the molding rotary shaft, the polymer is polymerized and then cooled to a certain temperature. It takes a relatively long time to perform welding and integration, and in the meantime, there is a problem that a deviation or deformation occurs, and a neatly shaped tube cannot be obtained, and the product value is reduced.

The present invention was devised in order to solve such problems, and a method for efficiently manufacturing a high-precision synthetic resin spiral tube in which the shape and the wall thickness of the spiral ridge are made uniform, and to the method. It is an object of the present invention to provide an apparatus for bending a synthetic resin material to be used.

[Means for Solving the Problems]

In order to achieve the above object, a method for manufacturing a synthetic resin spiral tube according to the present invention is characterized in that a semi-molten band-shaped synthetic resin material is formed in an arc-like shape having an outer peripheral edge arranged in a water tank and having a larger diameter than a rotary shaft for molding. By feeding toward the forming plate formed on the curved forming surface and moving along the forming surface while covering the forming surface of the forming plate, in the bending direction of the synthetic resin spiral tube to be formed. While being continuously bent, it is formed into a ridge material composed of a base portion having a U-shaped or V-shaped cross section with horizontal edges at both ends and an open top, and this ridge material is being passed through the water tank. After being cooled to a temperature slightly lower than the softening temperature of the synthetic resin material, the molding rotary shaft is continuously supplied so that the one horizontal edge and the other horizontal edge of the adjacent protrusion are superposed. Horizontally wound spirally on the molding rotating shaft and superposed adjacent ridges While integrated by the synthetic resin material by interposing a synthetic resin material of a semi-molten state between parts of opposite sides is characterized in that continue to form a spiral ridge.

In this manufacturing method, the synthetic resin material in the semi-molten state interposed between the opposed side portions of the ridge member may be a band-shaped synthetic resin material having a width larger than the width of the ridge member,
It may be a string-shaped or thin string-shaped synthetic resin material.

In addition, as a bending molding apparatus for a strip synthetic resin material formed on a ridge member, a circle whose outer peripheral edge is larger in diameter than the molding rotary shaft is located below the ridge member winding start end side of the molding rotary shaft. A forming plate having a forming surface curved in an arc shape, a cross section of the forming surface being formed in a U-shape or a V-shape, and being curved in an arc shape in a direction along the outer periphery of the forming rotary shaft. It is arranged, the base end side of the molding plate is directed to the introduction side of the band-shaped synthetic resin material, and the front end side of one side horizontal edge portion of the adjacent ridge supplied to the molding rotary shaft and the other side horizontal edge. Face the outer peripheral surface of the rotating shaft for molding in a tangential direction so that the edges overlap, and further,
A water tank into which the molding surface of the molded plate is put is provided as a cooling means of the ridge member moving on the molding surface of the molded plate.

In this bending molding apparatus, an adjusting plate having a curved surface that guides the ridge material in sliding contact with the curved surface smaller than the bending radius of the molding plate is provided at the tip of the molding plate that is close to the molding rotation shaft. Alternatively, a suitable heating mechanism may be incorporated in this adjusting plate.

[Action]

Before the semi-molten band-shaped synthetic resin material is spirally wound around the molding rotary shaft, the outer peripheral edge placed in the water tank is formed on the molding surface curved in an arc shape with a larger diameter than the molding rotary shaft. By moving along the forming surface while supplying the material toward the forming plate and covering the forming surface of the forming plate, the material is continuously bent in the curved direction of the synthetic resin spiral tube to be formed, It is formed into a ridge having a base portion having a horizontal edge at both ends and having an open top and a U-shaped or V-shaped cross section, and the synthetic resin is softened while passing through the ridge in a water tank. Because it cools to a temperature slightly lower than the temperature,
The ridges are efficiently and uniformly cooled by cooling water from the inner and outer surfaces, and are supplied to the forming rotary shaft while maintaining a stable shape without the risk of deformation of the ridges, and are appropriately curved at the time of the supply. Therefore, winding on the forming rotary shaft can be easily and smoothly performed, and furthermore, the synthetic resin in a semi-molten state between the opposing side portions of the adjacent ridge members wound spirally on the forming rotary shaft. When the material is interposed, the synthetic resin material in the semi-molten state is cooled by the ridges to accelerate the curing, and the ridges are immediately integrated with the ridges via the synthetic resin. Articles are formed.

At this time, when a band-shaped synthetic resin material having a width larger than the width of the ridge member is used as the semi-molten synthetic resin material interposed between the opposed side portions of the ridge member, the band-shaped synthetic resin material is When a double tube as a tube can be manufactured, and a string-shaped or narrow band-shaped synthetic resin material is used, a synthetic resin spiral tube in which the inner surface of the ridge member becomes the inner wall surface of the tube can be manufactured.

Further, in order to bend the semi-molten belt-like synthetic resin material into the ridge member as described above, the outer peripheral edge provided in the water tank has a molding surface curved in an arc shape having a larger diameter than the molding rotary shaft. It is performed by moving along the molding surface while covering the molding surface of the molding plate being formed with the band-shaped synthetic resin material,
During the passage of the molded plate, the ridge material has a U-shaped or V-shaped cross-section with an open top, not to mention the outer surface, so that the inner surface is cooled by cooling water through the opening as well as the outer surface. It is cooled efficiently and supplied to the forming rotary shaft from the tip of the formed plate.

At this time, an adjusting plate having a curved surface which guides the ridge member in sliding contact and formed to be smaller than the bending radius of the formed plate is disposed at the tip end of the formed plate. The ridges are wound more smoothly, and the adjustment plate is equipped with an appropriate heating mechanism so that the ridges can be adjusted to the optimum temperature for winding and welding and then formed. Can be supplied to the rotating shaft.

〔Example〕

The embodiment of the present invention will be described with reference to the drawings. (1) is a rotary shaft for molding, and a plurality of cylindrical shafts (1a) (1a)...
(1a) are arranged at predetermined intervals on a concentric circle, and one end side of these cylindrical shafts (1a) is rotatably supported by the machine frame (16), and an appropriate rotation drive mechanism (not shown) , So that they can be simultaneously rotated in the same direction.

The plurality of cylindrical shafts (1a) constituting the forming rotary shaft (1) are supported at both ends by a center shaft (2) via links (3) and (4). By rotating the links (3) and (4) about the shaft (2) as a fulcrum through an appropriate mechanism, the diameter of the molding rotary shaft (1) is expanded or contracted according to the diameter of the synthetic resin spiral tube B to be formed. The molding rotating shaft (1) may be formed by one rotating shaft, or a plurality of rotating rollers may be provided on the surface in a state of being arranged in parallel in the winding direction. It may be constituted by a shaft body.

(5) is a forming plate which constitutes a bending forming device disposed below the winding start end side of the forming rotary shaft (1), and is formed into a donut shape with a part of the cutout removed, and the cutout one end is formed. the outer periphery of the belt-like synthetic resin material which is disposed obliquely above the tangential to the ends (a ₁₎ of the extrusion means of the nozzle (6) forming a rotational axis a cut other end with directing (1) It is fixed to the machine frame (16) or the like in a state where it faces tangentially to the surface.

The outer peripheral edge of the forming plate (5) is curved in an arc shape having a diameter larger than that of the forming rotary shaft (1), and both sides thereof are cut off by an appropriate width to have a cross section having a constant width and a constant height. A notch (8) formed on a U-shaped molding surface (7) and further cut from the outer peripheral end surface of the molding surface (7) at an appropriate interval in the circumferential direction so as to be larger than the height of the molding surface (7). ) Is provided.

(9) is an adjusting plate attached to the other end of the cutout of the forming plate (5), that is, the tip, and the forming surface (7) of the forming plate (5) has a thickness.
Of the forming plate (5) from the lower end connected to the forming surface (7) to the upper end close to the outer circumferential surface of the forming rotary shaft (1). It is formed on a curved surface (10) that changes from the outer diameter of (7) to near the outer diameter of the molding rotary shaft (1).

The adjusting plate (9) has a lower end fitted into a fitting groove (11) formed in the end of the molding plate (5) and is detachably attached, and a synthetic resin spiral tube (B) to be formed. ), Ie
It can be replaced with another adjusting plate having a curved surface (10) corresponding to the diameter of the forming rotary shaft (1).

(12) is a heating mechanism such as a heater built in the adjusting plate (9). It should be noted that as such heating means, blowing of warm air from the outside or the like may be adopted.

(13) is a water tank in which portions other than both ends of the molded plate (5) are immersed, and a ridge formed of a belt-shaped synthetic resin material (A ₁ ) sliding on the molding surface (7) of the molded plate (5). It cools the material (A ₂ ).

Reference numeral (14) is a nozzle of extrusion molding means for supplying the semi-molten synthetic resin material (C) to the molding rotary shaft (1).

In order to manufacture the synthetic resin spiral tube (B) using the apparatus configured as described above, it is necessary to form the molded plate (5) from the nozzle (6).
While extruding a flat-belt-shaped synthetic resin material (A ₁ ) having a constant width wider than the width of the molding surface (7) of ( ₁ ) in the shape of a flat belt or the molding surface (7) of the molding plate (5) A strip-shaped synthetic resin material (A ₁ ) is moved along the molding surface of the molding plate (5) while covering the molding surface of the molding plate (5) curved in an arc shape having a diameter larger than that of the molding shaft. (A ₂ ), and this ridge (A ₂ ) is spirally wound from the forming plate (5) to the forming rotary shaft (1) by the rotation of the forming rotary shaft (1). The production method will be described in detail below.

First, for example, when a semi-molten band-shaped synthetic resin material (A ₁ ) made of a hard synthetic polyolefin resin such as polyethylene resin or polypropylene resin is supplied from the nozzle (6) to the molding surface (7) of the molding material (5). While the strip-shaped synthetic resin material (A ₁ ) covers the molding surface (7) of the molding plate (5),
It moves while keeping its shape by the molding surface (7).

At this time, when the belt-shaped synthetic resin material (A ₁ ) is supplied to the molding plate (5) in a flat band state, a roller (not shown) is used for the molding surface (7) of the molding plate (5). The belt-shaped synthetic resin material (A ₁ ) may be bent by this roller and molded while pressing from the end surface of the molding surface (7) to both side surfaces. It is desirable to supply the synthetic resin material (A ₁ ) to the molding surface (7) while extruding the synthetic resin material (A ₁ ) in a shape along the molding surface (7) of the molding plate (5).

In this way, the strip-shaped synthetic resin material (A ₁ ) supplied to the molding surface (7) of the molding plate (5) has its both side edges formed between the molding surface (7) and the outer peripheral edge of the molding plate (5). horizontal edge in sliding contact with the stepped peripheral portion _{(15) (a 1) (} a 2) and became a U-like lip material forming the (a _2), this projection member is held (a ₂ ) Slides on the forming surface (7) and passes through the water tank (13) to reach the adjusting plate (9). During this time, the ridges (A ₂ ) are cooled to a temperature slightly lower than the softening temperature of the resin by the cooling water in the water tank through the opening of the base portion, not to mention the outer surface of the ridge member (A ₂ ). Hold and molding surface (7)
Is formed in a state of being curved in the longitudinal direction along with.

At this time, the notch (8) provided at a plurality of locations on the outer peripheral portion of the forming plate (5) allows the ridge (A ₂ ) to pass through the opening of the base.
Is also cooled from its inner surface side, and reaches the adjusting plate (9) by being subjected to uniform and rapid cooling action over the entire length.

Further, while the ridge member (A ₂ ) passes through the curved surface (10) of the adjusting plate (9), the ridge member (A ₂ ) is curved without further deformation and the heating mechanism (A ₂ ). After being precisely adjusted to a constant temperature slightly lower than the softening temperature by 12), it is spirally wound around the forming rotary shaft (1).

In the molding rotary shaft (1), the other side a horizontal edge of the one side horizontal edges of the preceding ridge material (A ₂₎ (a ₁₎ ridge then wound onto material (A ₂₎ (A ₂ ) is spirally wound so as to be polymerized, and at this time, the semi-molten synthetic resin material (C) is discharged from the nozzle (14) at these horizontal edges (a ₁ ) (a ₂ ), And is welded in a state of being sandwiched by the horizontal edges (a ₁ ) (a ₂ ) and wound into a spiral while being integrated.

At this time, the synthetic resin material (C) in the semi-molten state is cooled by the horizontal edge portions (a ₁ ) and (a ₂ ) to accelerate the curing, and the welding and integration are rapidly performed in a short time. ridge member Te synthetic resin spiral tube while forming a spiral ridge (A3) by (a ₂₎ (B) in which are continuously produced.

In this manufacturing method, as the semi-molten synthetic resin material (C), a flat strip having a width slightly larger than the width between the horizontal edges (a ₁ ) (a ₂ ) of the ridge material (A ₂ ). One is pushed out from the nozzle (14) and, as shown in FIG. 3, one side edge of the ridge (A ₂ ) preceding the one side edge of the semi-molten synthetic resin material (C) ( a ₁₎ and the next ridge member of winding (a ₂₎ of the other side horizontal edges (a ₂₎ projecting strip material on the other side edge portion with is sandwiched integrally between (a ₂₎ one When the side horizontal edge (a ₁ ) is polymerized and welded, the flat band-shaped synthetic resin material (C) spirally wound on the forming rotary shaft (1) makes the synthetic resin spiral tube (B) flat. A double pipe having an inner peripheral wall surface can be obtained.

Also, as the semi-solid synthetic resin material (C), a string-like material substantially equal in width to the horizontal edges (a ₁ ) (a ₂ ) of the ridge member (A ₂ ) is extruded from the nozzle (14), As shown in FIG.
One side horizontal edge (a ₁ ) of the ridge member (A ₂ ) preceding the string-shaped synthetic resin material (C) and the other horizontal edge portion (a) of the ridge member (A ₂ ) to be wound next if brought into clamped integrated between _2), a single tube inner surface of the spiral ridge (A3) becomes the inner wall surface of the tube formed by the ridge member (a ₂₎ is produced.

In addition, even if the synthetic resin material (C) extruded from the nozzle (14) is the same synthetic resin material as the ridge material (A ₂ ),
A different kind of synthetic resin material may be used.

The molding surface (7) of the molding plate (5) in the above embodiment
Is formed by the outer peripheral end surface of the molded plate (5),
As shown in FIG. 8 and FIG. 8, circular rolls (17) (17)... (17) are formed on the arc-shaped outer peripheral portion of the forming plate (5) at appropriate intervals.
Is rotatably supported by a shaft, and the peripheral surface and both side surfaces of the roll (17) form a molding surface (7) of the same ridge (A ₂ ) as described above, and the shaft (18) forms a ridge. (A ₂₎
The horizontal edges (a ₁ ) (a ₂ ) of the above may be formed. In this case, the adjusting plate (9) is, of course, disposed on an extension of the roll (17). In addition, circular roll (17) (1
7) ... Both sides of (17) may be formed to have a small diameter, and the horizontal edges (a ₁ ) (a ₂ ) of the ridges (A ₂ ) may be formed on the outer peripheral surfaces thereof.

Further, the forming surface of such a forming plate (5) is formed in a U-shaped cross section, but may be formed in an appropriate mountain shape such as a V-shape other than such a cross-sectional shape.

〔The invention's effect〕

As described above, according to the synthetic resin pipe manufacturing method of the present invention, the outer peripheral edge provided in the water tank is formed before the semi-molten band-shaped synthetic resin material is spirally wound around the forming rotary shaft. By feeding toward the forming plate formed on the forming surface curved in a circular arc having a diameter larger than that of the rotating shaft for coating and moving the forming surface of the forming plate while covering the forming surface,
It is bent continuously in the curved direction of the synthetic resin helical tube to be formed, and is formed into a ridge member having a U-shaped or V-shaped cross section with horizontal edges at both ends and an open top. Since the ridge material is cooled to a temperature slightly lower than the softening temperature of the synthetic resin material while passing through the water tank, the inner surface as well as the outer surface of the ridge material is provided on the base portion. Cooled efficiently by the cooling water through the opening, the ridge member is uniformly cooled as a whole, and has a stable shape without the risk of deformation of the ridge member and while maintaining its thickness integrated. It can be supplied to the molding rotary shaft, and is appropriately curved at the time of the supply, so that the winding on the molding rotary shaft can be easily and smoothly performed, and further, the spiral shape is formed on the molding rotary shaft. It is wound in a semi-molten state between the opposite sides of the adjacent strips. When the synthetic resin material is intervened, the semi-molten synthetic resin material is cooled by the ridge material to promote hardening, and the ridge materials are immediately welded and integrated via the synthetic resin material. As a result, the spiral ridges formed by the ridge material can be formed in an orderly manner, and highly accurate synthetic resin spirals can be efficiently manufactured.

Further, when a strip synthetic resin material having a width larger than the width of the strip material is used as the semi-molten synthetic resin material interposed between the opposite side portions of the strip material, the strip synthetic resin material is A double pipe to be a pipe can be manufactured, and when a string-shaped or narrow strip-shaped synthetic resin material is used, it is possible to manufacture a synthetic resin spiral tube in which the inner surface of the ridge material serves as the inner wall surface of the tube.

Further, as an apparatus for bending and molding a semi-molten band-shaped synthetic resin material into a ridge material as described above, a part of the outer peripheral edge is formed below the ridge material winding start end side of the molding rotary shaft. A forming surface curved in an arc shape having a diameter larger than that of the rotary shaft for use, and a cross section of the forming surface is formed in a U-shape or a V-shape;
A forming plate which is curved in an arc shape in a direction along the outer periphery of the forming rotary shaft is provided, and a base end side of the forming plate is directed to an introduction side of the belt-shaped synthetic resin material, and a tip end side is formed. The one side horizontal edge and the other side horizontal edge of the adjacent ridges supplied to the rotary shaft face tangentially to the outer peripheral surface of the rotary shaft for molding so that the horizontal edge of the other side overlaps. Since a water tank in which the molding surface of the molding plate is immersed is arranged as a cooling means for the ridge material moving on the molding surface of the strip-shaped synthetic resin material in a semi-molten state by the molding surface of the molding plate. Can be formed into a ridge member having an accurate shape, and can be smoothly introduced from the front end thereof to the forming rotary shaft while being appropriately curved while being efficiently and uniformly cooled by cooling water from the inner and outer surfaces.

Further, the ridge member formed by this forming plate can be appropriately hardened by the cooling means composed of the water tank while passing through the forming plate to prevent the occurrence of shape deformation, and at the same time, the above-mentioned forming rotary member. Welding and integration on the shaft can be promoted.

At this time, an adjusting plate having a curved surface which guides the ridge member in sliding contact and formed to be smaller than the bending radius of the formed plate is disposed at the tip end of the formed plate. The ridges are wound more smoothly, and the adjustment plate is equipped with an appropriate heating mechanism so that the ridges can be adjusted to the optimum temperature for winding and welding and then formed. It can be supplied to the rotary shaft.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a simplified plan view of a manufacturing apparatus, FIG. 2 is a simplified front view, and FIG. 3 is an example of a synthetic resin spiral tube manufactured on a rotary shaft for molding. Partial sectional view, fourth
The figure is a partial cross-sectional view of a synthetic resin spiral tube having another structure, and FIG.
FIG. 6 is a front view of the bending apparatus, FIG. 6 is a side view thereof, and FIG.
FIG. 8 is a front view showing another example of the bending apparatus, and FIG. 8 is a side view thereof. (1) ... Rotating shaft for molding, (5) ... Molding plate, (6) ...
... Nozzle, (7) ... Molding surface, (9) ... Adjustment plate, (1
0) ...... curved surface, (12) ...... heating mechanism, (13) …… water tank, (14) …… nozzle, (A ₁ ) …… band-shaped synthetic resin material,
(A ₂ ) ... ridge material, (B) ... synthetic resin spiral tube, (C)
…… Synthetic resin material, (a ₁ ) (a ₂ ) …… Horizontal edge.

Claims (6)

(57) [Claims] 1. A semi-molten belt-shaped synthetic resin material is directed toward a molding plate having an outer peripheral edge disposed in a water tank formed on an arc-shaped molding surface having a larger diameter than a molding rotary shaft. By feeding and moving along the molding surface of the molding plate while covering the molding surface, the synthetic resin spiral tube is continuously bent in the bending direction and has horizontal edges at both ends. In addition, a ridge material having a U-shaped or V-shaped base portion with an open top is formed, and the ridge material is cooled to a temperature slightly lower than the softening temperature of the synthetic resin material while passing through the water tank. After that, one side horizontal edge portion and the other end horizontal edge portion of the adjacent ridge member are continuously supplied to the forming rotary shaft so as to be superimposed, and are spirally wound on the forming rotary shaft and adjacent to the forming rotary shaft. A semi-molten synthetic resin material is interposed between the opposite side portions of the horizontal edges where the ridges are overlapped. Method for producing a synthetic resin helical tube, characterized in that continue to form a spiral ridge while integrated by the synthetic resin material by. 2. The synthetic resin material in a semi-molten state interposed between opposing side portions of the ridge member is a band-like synthetic resin member having a width larger than the width of the ridge member. The method for manufacturing a synthetic resin spiral tube according to claim 1, wherein the inner wall of the tube is formed by the following. 3. The semi-molten synthetic resin material interposed between the opposite side portions of the ridge material is a string-shaped or narrow strip-shaped synthetic resin material, and the synthetic resin material is exposed on the inner surface side of the pipe. The method for producing a synthetic resin spiral tube according to claim 1, wherein the inner surface of the ridge material is used as the inner wall surface of the tube without causing it. 4. A molding surface whose outer peripheral edge is curved in an arc shape having a diameter larger than that of the molding rotary shaft, and which is below the projecting strip winding start end side of the molding rotary shaft, and which has a cross section. Is formed in a U-shape or a V-shape, and a molding plate formed by curving in an arc shape in the direction along the outer periphery of the molding rotation shaft is provided, and the base end side of the molding plate is a belt-shaped synthetic resin. The outer peripheral surface of the forming rotary shaft so that the one side horizontal edge and the other side horizontal edge of the adjacent ridges supplied to the forming rotary shaft are superimposed while being directed to the material introduction side. Face tangentially to
A bending molding apparatus for a belt-shaped synthetic resin material, characterized in that a water tank having the molding surface of the molding plate inserted therein is provided as a cooling means for the ridge material moving on the molding surface of the molding plate. 5. An adjusting plate having a curved surface for slidingly guiding a ridge material formed smaller than the bending radius of the forming plate is provided at the tip of the forming plate in the vicinity of the forming rotary shaft. A bending molding apparatus for a belt-shaped synthetic resin material according to claim 1. 6. A bending molding apparatus for a belt-shaped synthetic resin material according to claim 1, wherein an appropriate heating mechanism is incorporated in the adjusting plate.