JPH0691781A - Method and apparatus for manufacturing pipe from thermoplastic resin foamed sheet - Google Patents

Abstract

PURPOSE:To always bring a sheet into surface contact even if a strain exists at part of a circumference due to deformation at the time of fusion-bonding and to manufacture a pipe of an arbitrary shape by fusion-bonding cut edges of the sheet in an effectively butted state, and forming a non-pressurized part at the circumference for releasing the generated strain. CONSTITUTION:A flat platelike sheet (a) drawn one by one from a sheet supply box 1 is placed on a conveyor 2, wound in a pipe state through guide frames 6, 7 while advancing forward, pressurized from vertical and lateral directions by an outer surface control roll 10, and corrected at its periphery to a predetermined shape such as a circumferential state. In this case, the sheet (a) is pressed from right and left sides by standing rolls 12..., 12..., but since upper horizontal rolls 11,... exist, both side edges of the sheet (a) are previously heated by a heater 9, and hence the cut edges are fusion-bonded so that the sheet is formed in a cylindrical shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing an integral pipe by abutting and adhering corresponding side edges of a single thermoplastic resin foam sheet.

[0002]

2. Description of the Related Art In order to manufacture a synthetic resin tubular body, there are a continuous molding method using an extruder and a method of forming a sheet material into a cylindrical shape by fusing side edges, and this method requires a large-scale apparatus. Since it is not necessary, it is widely used, but there is a disadvantage that a uniform tubular body cannot be obtained due to strain on the fused portion of the sheet. Therefore, as shown in FIG. 7, the sheet material a ′ ... Is supplied in a state of a set of two sheets that are stacked one above the other, and while being moved forward, both side edges are fused (FIG. 5 (A)). Then two sheets a '
a'is isolated from each other and gradually finished to have a circular cross section (Fig. 7).
Methods (B) and (C) have been developed (Japanese Patent Publication No. S58-58-
29730).

[0003]

Since the sheet produced by the above method is fused on both side edges of the sheet as shown in FIG. 7 (A), the fused positions correspond to two corresponding points on the circumference. However, there is an advantage that the cross-sectional shape can be a relatively uniform circumference compared to the usual method in which one sheet is rounded, but the cut edges of the upper and lower two sheets are still V-shaped. As a result, defective fusion tends to occur at the fused portion, and when the width of the sheet is not uniform, or due to deformation during fusion, distortion occurs in part of the circumference, resulting in poor fusion and variations in pipe shape. Etc. may occur. The present invention has been made in order to solve the above-mentioned point, and even if the width dimension of the thermoreversible resin foam sheet is not uniform, and there is a distortion in a part of the circumference due to the deformation at the time of fusion bonding. Also, it is an object of the present invention to provide a method and an apparatus capable of manufacturing a pipe having an arbitrary shape, which can always be surface-bonded and whose cross-sectional dimension can be easily changed.

[0004]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that the fusion of sheets should be performed in a state where the cut portions are butted against each other in a plane. And, it was found that it is desirable to leave a portion for releasing the strain of the sheet material generated at the time of fusion, and as a result of further investigation, fusion was performed with the cut edges of the sheet being surely aligned. In addition, in order to release the generated strain, the above object is solved when the sheet material is structured so as to be guided and held in a cylindrical shape while pressing the peripheral surface with a large number of rollers so that a non-pressed portion is created on the circumference. I found that I could do it. That is, according to the present invention, a thermoplastic foam sheet cut into a short strip is run in the longitudinal direction and fed into a guide frame to be rounded into a pipe shape in the width direction, and both side edges are fused to form a pipe. In doing so, a sheet rolled into a pipe shape is surrounded by an outer surface regulating roll having a group of rollers arranged in a polygonal shape selected in advance according to the cross-sectional shape of the pipe, and cuts on both side edges of the sheet to be fused. A method for manufacturing a pipe from a thermoplastic resin foam sheet is provided which is supported around any of these rollers and is linearly pushed from the left and right to be abutted against each other. Further, according to the present invention, a belt conveyor that sends out a thermoplastic foam sheet cut into a short shape to the front, a guide frame that rounds the sent sheet into a pipe shape, and a pipe cross section that surrounds the outer surface of the rolled sheet. With a large number of rollers arranged in a polygonal shape that holds the
Provided is a device for manufacturing a pipe from a thermoplastic resin foam sheet, in which the assembled outer surface regulation rolls are sequentially arranged, and a heater for heating the sheet is attached at a proper position of the sheet passage surrounded by the guide frame and the outer surface regulation roll. To be done.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the apparatus according to the present invention will be described with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 is a sheet feeding box, which is formed in a rectangular frame shape with upper and lower surfaces open, and has a raw material inside. A large number of foamed resin sheets a ... Cut into short strips are stacked and accommodated. Next, 2 is a belt conveyor that stacks the respective sheets taken out from the slits on the front of the supply box and feeds them one by one forward. 3 is provided above the conveyor 2 so as to stack the sheet a together with the conveyor 2.
It is a narrow endless belt for pulling out one by one. Reference numeral 4 is a support piece whose one end is supported by the rear end of the endless belt 3 and 5 is a holding piece which is attached to the other end of the support piece 4 and presses the surface of the sheet to guide the sheet onto the conveyor 2.

Next, 6 and 7 are guide frames made gradually narrower toward the front, 8 is a shaping heater for heating the inside of the sheet a wound around the guide frame 6,
Reference numeral 9 is a heater for fusing both side edges of the sheet wound in a pipe shape in the width direction, and 10 is an outer surface regulating roll surrounding the outer periphery of the sheet wound in a tubular shape, and as shown in FIG. Formed by a large number of horizontal rolls 11 ..., Vertical rolls 12 ... and driven by a motor 13. Reference numeral 14 denotes a heating / cooling blower for heating and cooling the outer surface of the pipe-shaped sheet. The "polygonal shape selected by the cross-sectional shape of the pipe" in the present invention means a quadrangular shape in the case of a cylindrical pipe, a triangular shape in the case of a triangular tubular pipe, and a triangular shape in the case of a quadrangular tubular pipe. In the case of a rectangular pipe having a pentagonal shape or more, it is preferable to select the rectangular shape. In the case of manufacturing a polygonal pipe such as a triangle or a quadrangle, a sharper corner portion is formed by inserting a hot blade from the inside of the pipe to the corner portion of the pipe. Further, according to the present invention, by adopting a roll in which the outer surface regulating roll is arranged in a polygonal shape, it is possible to adjust the sheet width error and the sheet material distortion at the polygonal inner corner portion. For example, when manufacturing a cylindrical pipe, the one shown in FIGS. 3 and 4 is optimal. Further, when the pipe shape and the outer surface regulating roll shape are the same, the adjusting action for the error of the width of the corner portion 15 becomes small. Therefore, it is preferable to make the roller interval W forming one side of the polygon wide. The outer surface regulation roll does not have to surround the entire circumference of the pipe. For example, as shown in FIGS. 5 and 6, when one side is formed by the conveyor 2, the pipe is provided at least in a portion other than the conveying means such as the conveyor. You just have to enclose. Further, it is preferable that the outer surface regulation roll is driven in consideration of the feeding of the pipe. Further, the plurality of arranged roller groups may be a plurality of stacked layers (triple) as shown in FIG. 3 or may be a single layer, but from the viewpoint of effect, four or more layers are stacked. Stacked layers are preferred. Furthermore, in the case of stacking a plurality of stages, for example, in the case of a quadrangular shape, a combination of the left and right rolls (upright rolls) as the first stage, the upper and lower rolls (horizontal rolls) as the second stage, etc. is possible. Further, the thermoplastic foam sheet used in the present invention has a base resin such as a polyolefin-based resin or a polystyrene-based resin, and an extruded foamed sheet obtained by an extrusion method or a molded article obtained by a bead foaming method is used. Sliced products are used, especially,
Optimal for those with a thickness of 4-15 mm.
Further, for example, in the case of manufacturing a cylindrical pipe, a pipe having a diameter of +5 to 10% of the distance between the left and right outer surface regulating rolls can be manufactured with one outer surface regulating roll. It should be noted that, in the above-described embodiment, the adhesive means by heat fusion is exemplified as the adhesive means, or the adhesive means by an adhesive or the like can be adopted as the other adhesive means.

[0007]

The present invention has the above-mentioned structure, and is a flat sheet a drawn out from the sheet supply box 1 one by one.
While being placed on the conveyor 2 and moving forward, it is wound into a pipe shape through the guide frames 6 and 7, and is pressed from the upper, lower, left, and right by the outer surface regulation roll 10 to correct the periphery to a desired shape, for example, a circumferential shape. In this case, as shown in FIG. 4, the sheet a is pressed from the left and right by the upright rolls 12 ... 12 but the upper horizontal rolls 11 ... It is pressed in the state of being aligned.
At this time, both side edges of the sheet a are previously heated by the heater 9 (FIG. 2).
Since the sheets are heated by, the cuts are fused to each other and the sheet has a cylindrical shape. By the way, the sheet a, which is a strip-shaped original, is not necessarily cut into equal widths in advance, but even in such a case, an error in the sheet width causes an error in the vertical roll 12.
..., the corner portion 15 formed at each end of the horizontal roll 11
Since the absorption is adjusted by the part, the cuts will always be correctly aligned, and a uniform periphery can be obtained. Further, even when the target pipe diameter is changed to some extent by this corner portion, it can be dealt with without changing one outer surface regulating roll. As described above, according to the method and apparatus of the present invention, the cut edges of the sheet a are always bonded orthogonally by surface contact, and the rolls of the outer surface regulating roll 10 are vertical rolls, horizontal rolls, and diagonal rolls. By making the required polygonal shape, a pipe having an arbitrary cross-sectional shape can be produced, which is extremely efficient.

[Brief description of drawings]

FIG. 1 is a plan view of a pipe manufacturing apparatus according to the present invention.

FIG. 2 is a side view of the pipe manufacturing apparatus according to the present invention.

FIG. 3 is a perspective view of a typical outer surface regulation roll used in the present invention.

FIG. 4 is an explanatory view showing a state in which a side edge of a sheet is adhered by an outer surface regulation roll used in the present invention.

FIG. 5 is a perspective view of another outer surface regulation roll used in the present invention.

FIG. 6 is a perspective view of another outer surface regulation roll used in the present invention.

FIG. 7 is an explanatory view of a manufacturing example of a pipe according to a conventional technique.

[Explanation of symbols]

 1 sheet supply box 2 belt conveyor a sheet 6,7 guide frame 8,9 heater 10 outer surface regulation roll 11 horizontal roll 12 vertical roll

Claims (2)

[Claims] 1. A thermoplastic foam sheet cut into a strip shape is run in the longitudinal direction and fed into a guide frame to be rounded into a pipe shape in the width direction and both side edges in the width direction are fused to form a pipe. In doing so, the pipe-shaped sheet is surrounded by an outer surface regulation roll having a group of rollers arranged in a polygonal shape which is selected in advance by the pipe cross-sectional shape, and the cut edges of both side edges of the sheet to be bonded are A method for producing a pipe from a thermoplastic resin foam sheet, which is supported around one of these rollers and is linearly pushed from the left and right sides to be butted against each other. 2. A belt conveyor for sending out a thermoplastic foam sheet cut into a strip shape to the front, a guide frame for rounding out the sent sheet into a pipe shape, and a pipe cross section surrounding the outer surface of the rolled sheet with a predetermined contour. A plurality of roller groups arranged in a polygonal shape to be held on the outer surface regulating roll are sequentially arranged, and a sheet adhering means is attached at a proper position of a sheet passage surrounded by the guide frame and the outer surface regulating roll. Equipment for manufacturing pipes from thermoplastic resin foam sheets.