JPH04305428A - Apparatus for preparing synthetic resin pipe - Google Patents

Abstract

PURPOSE:To accurately prepare a synthetic resin pipe having a spiral reinforcing ridge. CONSTITUTION:In an apparatus for preparing a synthetic resin pipe by spirally winding a strip like material 3 having a ridge 3b formed to the central part thereof round a plurality of the molding shafts 1... arranged on an imaginary column, sizings 6, 6 each having a cross-sectional shape fitted to the inner surface shape of the strip like material are arranged between the first and second molding shafts 1a, 1b and the second and third molding shafts 1b, 1c at the winding start part of the strip like material 3 and the strip like material 3 is spirally wound round the molding shafts along said sizings 6, 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a synthetic resin pipe having a spiral reinforcing strip on the outer periphery of the pipe wall.

0002

[Prior Art] Generally, this type of manufacturing equipment has a plurality of forming shafts arranged along the outer surface of an imaginary cylinder, and each forming axis is inclined at a predetermined angle with respect to the axis of the imaginary cylinder. A belt-shaped material having a convex strip on each molding shaft is wound in a spiral strip to continuously mold a synthetic resin tube provided with a spiral reinforcing strip on the outer periphery of the tube wall.

0003

[Problems to be Solved by the Invention] When a synthetic resin pipe is manufactured using the above-mentioned manufacturing apparatus, when the band-shaped material is wound around the molding shaft, it is wound and fused so that the side edges of the material are sequentially overlapped. At this time, the convex shape of the strip material is deformed. In other words, since the strip material is semi-molten so that the overlapping side edges are fused, when the strip material is wound around the forming shaft, compressive force is applied to the inner periphery of the ridges of the strip material, and tension is applied to the outer periphery of the ridges. The protrusions are deformed into a flat shape when force is applied.

[0004] Furthermore, the above-mentioned load changes on each forming axis and between each forming axis. That is, since the strip material is curved in an arc shape on the forming axis, the inner circumferential side of the convex Compressive force acts on the outer periphery of the ridges, and tensile force acts on the outer periphery of the ridges, but since the strip material is pulled linearly between the forming shafts, compressive force acts on the outer periphery of the ridges, and tensile force acts on the inner periphery of the ridges. There is a problem in that the deformation of the protrusions becomes even greater when such loads act alternately.

[0005]

[Means for Solving the Problems] The present invention has been developed to solve the above-mentioned problems. Among the plurality of forming shafts arranged along the outer surface of a virtual cylinder, at least one of the belt-shaped material A sizing is provided between the forming shaft located near the beginning of winding and the forming shaft adjacent thereto, which has a shape that matches the inner shape of the convex strip of the strip material and is curved to approximately follow the outer surface shape of the virtual cylinder. The present invention is characterized in that the shape of the protrusion is shaped.

[0006]

[Function] According to the above structure, the load acting on the inner and outer circumferences of the convex strips of the strip material does not change alternately, and the inner shape of the convex strips is shaped by sizing, so that the convex strips are shaped. Since deformation is prevented, the original shape of the reinforcing strip formed by the ridges can be reliably maintained. Furthermore, by reliably maintaining the original shape of the protruding strips in this way, the winding speed of the strip material around the forming shaft can be increased, and productivity can be improved.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the figure, 1... is a plurality of forming shafts arranged along the outer surface of a virtual cylinder A having a predetermined radius, and each forming shaft 1... is an axis of the virtual cylinder A. They are configured to be inclined at a predetermined angle with respect to the core, and to be driven and rotated at the same speed in conjunction with a drive device (not shown). The molding shaft 1 may be provided with a large number of roller shafts rotatably supported by a cylindrical retainer on its outer periphery. In this case, each roller shaft is connected to the forming shaft 1.
By tilting the molding shaft 1 with respect to the axis of the molding shaft 1, it is not necessary to tilt the molding shaft 1 as described above.

[0008] A semi-molten band material 3 is wound around the forming shaft 1, which is continuously extruded using an extrusion device and a forming die 2 (not shown). By driving and rotating the forming shafts 1, the strip material 3 is sequentially wound onto each forming shaft 1. At this time, since the forming shaft 1 is inclined, the strip material 3 is wound up spirally, and the spiral pitch is made larger than the width of the strip material 3. The side edges of the tubes 3 are successively overlapped and welded together to form a synthetic resin tube with an appropriate diameter.

[0009] The strip material 3 also has a protruding strip 3b having a U-shaped cross section and a protruding strip 3b that becomes the reinforcing strip 5 after curing.
It is formed into a cross-sectional shape having a pair of flat flanges 3a, 3a that extend from the open end of b to both sides and become the tube wall 4 after hardening, and therefore, it is manufactured using the strip-shaped material 3 as described above. The synthetic resin pipe includes a pipe wall 4 formed by flanges 3a, 3a, and a spiral reinforcing strip 5 formed on the outer periphery of the pipe wall 4 by protrusions 3b.

On the other hand, among the above-mentioned forming shafts 1..., the first forming shaft 1a located near the beginning of winding the strip material 3 and the second forming shaft 1b adjacent thereto. The sizings 6, 6 are interposed between the second forming shaft 1b and the third forming shaft 1c adjacent thereto.

[0011] The sizing 6, 6 is curved in an arc shape approximately along the imaginary cylinder A, and has a platform portion 6a that supports the flanges 3a, 3a of the strip material 3, and an inner shape of the protrusion 3b. It is provided with a protruding portion 6b having an adapted U-shaped cross section. Further, a cooling water passage 6c is formed near the surface layer of this platform 6a, and an inflow passage 6d is formed in communication with one end of the water passage 6c, and an outflow passage 6e is formed in communication with the other end. There is.

The manufacturing apparatus of the present invention is constructed as described above, and the semi-molten strip material 3 that is continuously extruded from the extrusion device and the molding die 2 is attached to each molding shaft 1.
...Wrap it manually so that it spans the upper part. At this time, the protrusions 6b of size 6, 6 are included in the protrusions 3b of the strip material 3.
, 6b fit together accurately.

In this state, each forming shaft 1 is driven to rotate, and the strip material 3 is wound up spirally so that the side edges thereof are sequentially overlapped, and each flange 3a, 3a of the strip material 3 is wound.
The tube wall 4 is formed by this, and the spiral reinforcing strip 5 is formed by the protruding strip 3b.

[0014] Therefore, each forming shaft 1 of the strip material 3
Since the strip material 3 is curved into an arc shape when it is wound up into the forming shaft 1... Immediately after winding the strip material 3, specifically, at the first winding point of the strip material 3.
Shaping the strip material 3 between the shaping shaft 1a and the second shaping shaft 1b and between the second shaping shaft 1b and the third shaping shaft 1c by sizing 6, 6, and sizing 6,
The sizing 6, 6 is curved into an arc to harden the strip material 3 to the extent that at least the protruding strips 3b of the strip material 3 are not deformed due to the cooling effect of the cooling effect caused by the cooling effect of the strip material 3 or the cooling effect of the circulation of cold water. The deformation of the protruding strips 3b is reliably prevented by arranging them along the molding surface so that no alternating loads (tensile force and compressive force) are applied to the strip material 3 during the semi-melting process. Convex strip 3
There is no deformation of the spiral reinforcing strip 5 formed by b.

In the described embodiment, the sizing 6 is interposed in two places between the forming shafts 1, but the sizing 6 may be placed in one place, or in three or more places.

[0016]

As described above, the synthetic resin pipe manufacturing apparatus of the present invention shapes the convex stripes of the semi-molten strip material by sizing immediately after winding the half-molten strip material around the forming shaft. Since tensile force and compressive force are not applied alternately to the ridges of the strip material during the semi-molten state, the ridges of the strip material do not deform during molding, and the ridges This makes it possible to reliably maintain the original shape of the formed reinforcing strip.

[0017] Furthermore, by reliably maintaining the original shape of the protrusions in this way, it is possible to increase the winding speed of the band-shaped material around the forming shaft, thereby improving productivity. It is something that plays.

[Brief explanation of drawings]

[Fig. 1] A partially cutaway plan view of the main part;

[Fig. 2] Same partially cutaway left end view,

FIG. 3 is a cross-sectional perspective view of sizing.

[Explanation of symbols]

1 Molding shaft 1a First forming shaft 1b Second forming shaft 1c Third forming shaft 3. Strip material 3a Flange 3b Convex strip 4 Pipe wall 5 Reinforcement strip 6 Sizing

Claims (1)

[Claims] [Claim 1] A plurality of forming shafts are arranged along the outer surface of a virtual cylinder, and a strip material having a convex strip is spirally wound around each of the forming shafts, so that the outer circumference of the pipe wall is In a manufacturing apparatus configured to continuously mold a synthetic resin pipe equipped with a spiral reinforcing strip, at least between a molding shaft located near the beginning of winding of the strip material and a molding shaft adjacent thereto. The synthetic resin is characterized in that the sizing is configured to shape the shape of the ridges by providing a sizing curved to approximately follow the outer surface shape of the imaginary cylinder and having a shape that matches the inner shape of the ridges of the band-shaped material. Pipe manufacturing equipment.