JP2010175050A - Pressure pipe having flexibility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure pipe constituted by integrally providing an outer pipe made of hard synthetic resin on an outer peripheral face of an inner pipe made of soft synthetic resin and having such bendability that prevents it from being extended even if it is bent and a tensile force is applied on it in the direction of length to prevent the inner pipe from being broken and enable the use of this pressure pipe for a long time. <P>SOLUTION: The outer pipe 2 made of hard synthetic resin is composed of an inner side belt-like member 4 being spirally wound around an outer peripheral face of the inner pipe 1 made of soft synthetic resin, forming rising side wall parts 4b, 4b at both side ends of a bottom wall 4a having fixed width integrally, and having an outward facing opening having a U-shaped cross section and an outer side belt-like member 5 forming suspension side walls 5b, 5b at both side ends of a top wall 5a having fixed width integrally and having an inward facing opening having a U-shaped cross section. Both of suspension side walls 5b, 5b of the outer side belt-like member 5 are engaged with the rising side walls 4b, 4b being adjacent on the inner side belt-like member 4 to overlap the former walls 5b, 5b on the latter walls 4b, 4b, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flexible pressure-resistant pipe used as a drain pipe, a water supply pipe, a wiring pipe, and a joint pipe.

  Conventionally, pipes with excellent flexibility such as soft synthetic resin pipes have been widely used as drain pipes and water supply pipes, but as pipes buried in the ground, pressure resistance against earth pressure etc. Therefore, a pressure-resistant pipe is adopted in which the above-described soft synthetic resin pipe is used as an inner pipe and the inner pipe is covered with an outer pipe made of a hard material such as hard synthetic resin.

  As this type of pressure-resistant tube, for example, as described in Patent Document 1, an inner tube made of a soft synthetic resin having a constant thickness over the entire length, and an outer peripheral surface of the inner tube is made of a hard material. It consists of an outer tube formed by spirally winding a band-shaped material, and the above-mentioned band-shaped material forming this outer tube is outwardly on both side ends of the bottom part having a certain width. It is formed in a fixed portion with a U-shaped cross section that is open outwardly by projecting a rising piece toward the other side, while the other half is formed in a direction opposite to the bottom side from the protruding end of the one rising side wall. It is formed in a covering portion having a U-shaped cross section that is opened inward by bending and inclining a descent piece to the protruding end of a ceiling portion having a certain width and projecting inward. The outer bottom surface of the bottom piece is fused and fixed to the outer peripheral surface of the inner tube. And a middle was intervention descent piece of the cover part structure of the space between the rising side wall.

  Further, as another pressure-resistant tube structure, as described in Patent Document 2, on the inner tube made of a soft synthetic resin having a constant thickness over the entire length, rising walls at both ends of the bottom wall portion are provided. A rigid synthetic resin strip having a U-shaped cross-section with an outward opening formed integrally with the portion, and the outer bottom surface of the bottom wall portion is fused and fixed to the outer peripheral surface of the inner tube; and A tube having a structure in which an outer tube is formed by connecting between protruding ends of rising side wall portions of adjacent strip-shaped members by a connecting strip made of a soft synthetic resin has been developed.

Japanese Utility Model Publication No. 62-172886 Japanese Utility Model Publication No. 63-69883

  However, according to the former pressure-resistant tube, in the outer tube made of a band-like material spirally wound on the inner tube, both sides of the fixing portion having a U-shaped cross section that opens outward in the band-like material part wound earlier. Since it has a structure in which the tip descending piece of the U-shaped covering section opened inward in the band-like material portion wound next in the middle between the rising pieces is movably intervened in the length direction of the tube, When a tensile force acts on the pipe, the tensile force is directly transmitted to the inner pipe pipe wall part between the bottom piece parts of the fixed part that is integrally fused to the outer peripheral surface of the inner pipe with a constant winding pitch, There is a problem in that the tube wall portion is elongated so as to be thinner, and as a result, the tube wall portion is damaged and cannot be used. Further, when the tube is bent with a tensile force applied, the tube wall portion is pulled with a larger force and is more easily damaged. Further, when a high-pressure fluid is circulated in the pipe, there is a possibility that the inner pipe expands and bursts while the outer pipe is extended by the pressure.

  Similarly, also in the latter pressure-resistant pipe, when a tensile force is applied to the pipe, the pipe wall of the inner pipe in which the strip-shaped material having a U-shaped cross section of the outward opening is spirally wound is wound on the inner pipe first. The inner pipe tube wall part between the bottom wall part in the worn strip part and the bottom wall part in the next wound strip part is easily stretched and damaged by the above-mentioned tensile force. In addition, the connecting band made of soft synthetic resin that connects between the protruding ends of the rising side wall portions of the adjacent band-shaped members may also be stretched by the above-described tensile force and may be damaged. When a large pressure is applied by the high-pressure fluid, there is a problem that the inner tube made of the soft synthetic resin may expand while expanding to expand in the diameter-expanding direction.

  The present invention has been made in view of such problems, and the object of the present invention is to provide a tensile force in the longitudinal direction even if it is bent despite having excellent pressure strength and flexibility. Even if a large internal pressure is applied, the flexible pressure-resistant tube can be used for a long period of time by preventing breakage of the inner tube made of a soft synthetic resin without substantially extending even when a large internal pressure is applied. To provide.

  In order to achieve the above object, the flexible pressure tube of the present invention comprises an inner tube made of a soft synthetic resin and an outer tube made of a hard material as described in claim 1, An inner band member having a U-shaped cross-section that is outwardly formed by integrally forming rising side wall portions having a constant height toward both sides of the bottom wall portion having a constant width, and a top having a constant width. It is comprised from the outer side strip | belt material of the U-shaped cross section opened inward formed by integrally forming the drooping side wall part toward both sides at the both ends of the wall portion, and the bottom wall portion of the inner strip member is The inner strip is spirally wound with a constant winding pitch on the outer peripheral surface of the inner tube in a state of being fused to the inner tube, and the rising side wall portion of the adjacent inner strip is Spirally wound with the same pitch as that of the inner strip in a state where it is sandwiched between both sides. And a side wall portion and the engaged to the inner wall surface of the stand up wall portion of the inner strip material structure.

  In the flexible pressure tube constructed as described above, the invention according to claim 2 is characterized in that the height of the hanging side wall portion of the outer belt-shaped member forming the outer tube and the height of the rising side wall portion of the inner belt-shaped material are as follows. Are formed at substantially the same height, and a protrusion is provided at the tip of the hanging side wall so as to come into contact with and separate from the inner wall surface of the rising side wall. It is characterized in that a ridge is provided in contact with the inner wall surface of the part so as to be able to contact and separate.

  On the other hand, the invention according to claim 3 is formed such that the height of the hanging side wall portion of the outer band-shaped material is different from the height of the rising side wall portion of the inner band-shaped material, and the rising side wall portion at the tip of the hanging side wall portion. A slidably engaged ridge is provided on the inner wall surface, and a slidably engaged ridge is provided on the leading end of the rising side wall portion. . In addition, the said outer tube | pipe is formed from the hard synthetic resin material or the metal material, as described in Claim 4.

  In the invention according to claim 5, the inner peripheral surface of the inner tube is formed as a smooth surface having the same diameter over the entire length, and the bottom of the inner belt-like member in the outer tube is formed on the outer peripheral surface of the inner tube. A spiral groove in which the wall portion is embedded is provided, and further, the tube wall portion between the spiral grooves is formed in a thick tube wall portion interposed between the outer wall surfaces of the adjacent rising side wall portions of the inner belt-like material. It is characterized by being.

  According to the first aspect of the present invention, the outer tube made of the hard material provided on the outer peripheral surface of the inner tube made of the soft synthetic resin has a constant height toward the outside at both side ends of the bottom wall portion having a certain width. An inner strip with an U-shaped cross section that is formed by integrally forming a rising side wall portion and an outwardly opening side wall portion that is inwardly formed at both ends of the top wall portion having a certain width. The inner strip is fixed to the outer peripheral surface of the inner tube with the bottom wall portion of the inner strip being fused to the inner tube. Is wound in a spiral shape with a winding pitch of the inner belt-like material and spirally wound with the same pitch as the inner belt-like material in a state where the outer belt-like material is straddled between the rising side wall portions of the adjacent inner belt-like materials. It has a structure in which the both side hanging side wall portions are engaged with the inner wall surface of the rising side wall portion. The outer tube can maintain a strong compressive strength over the entire length, and of course, even if a tensile force is applied to the tube, the inner strip in the outer tube is spirally wound on the inner tube. Since the inner side surface of the hanging side wall portion of the outer belt-shaped member facing the rising side wall portion is engaged with the inner side surface of the rising side wall portion in the state of being sequentially overlapped in the length direction of the pipe, And the outer tube | pipe which consists of an outer side strip | belt-shaped material does not extend | expand in the length direction of a pipe | tube.

  Accordingly, the entire pipe including the inner pipe made of the soft synthetic resin is prevented from extending in the pipe axis direction, so that the inner pipe can be prevented from being damaged due to excessive extension, and even if a large fluid pressure acts on the pipe. Further, expansion of the inner pipe can be suppressed by a hard outer pipe that does not cause elongation, and it can be used for a long time as a drain pipe, a water supply pipe, a joint pipe, or the like.

  Further, when the tube is bent, on the side of the outer tube wall that curves in a convex arc shape, a strip-shaped member portion wound in a spiral shape in the spiral direction of the inner strip-shaped member of the outer tube and the strip-shaped member Both side-hanging side walls in the outer belt-like material in which the rising side wall portion facing the belt-like material portion that is further wound around the belt-like material portion adjacent to the belt portion extends between these belt-like material portions Tilt in the direction approaching each other from the front end engaged with the base end portion toward the base end, with the base end portion of the inner wall surface facing the part as a fulcrum, and these opposing rising side walls with the tilt The inner wall of the inner tube between the two parts is compressed, and the outer belt-like material straddling between the rising side wall parts is separated from the inner wall surface of the base end part of the rising side wall part facing the tip of the both side hanging side wall parts. Curved along the curved surface of the convex arc Can be curved wall portion to smooth convex arcuate.

  On the other hand, in the inner tube wall portion curved in a concave arc shape, the strip-shaped member portion wound in a spiral in the spiral direction of the inner strip-shaped material of the outer tube with the bending of the flexible inner tube having flexibility. And the opposite side wall portion of the belt-shaped material portion that is wound around the belt-shaped material portion adjacently to the belt-shaped material portion, and the outside extends across the rising side wall portions. Tilt in the direction approaching each other from the base end abutting with the base end portion in contact with the front end portion of the inner wall surface of the hanging side wall portion of the belt-like material as a fulcrum, and according to the tilt, the outer band shape The material is curved along a concave arcuate curved surface, and the inner tube wall can be smoothly curved into a concave arc without causing wrinkles or the like in the inner tube.

  According to the invention according to claim 2, in the outer tube made of the hard material, the height of the hanging side wall portion of the outer belt-shaped material and the height of the rising side wall portion of the inner belt-shaped material are formed to be substantially equal. The protrusion of the hanging side wall is slidably engaged with the inner wall surface of the rising side wall, and the tip of the rising side wall is slidably engaged with the inner wall of the hanging side wall. Since the ridges are provided, the rising side wall portion of the inner band-shaped material and the hanging side wall portion of the outer band-shaped material facing the rising side wall portion can be joined in a state of being overlapped over substantially the entire height, When a tensile force is applied to the tube, the tensile force causes the rising side wall portion of the inner band member to move without moving the rising side wall portion of the inner band member or the hanging side wall portion of the outer band member in the length direction of the tube. Projection provided at the tip And the protruding portion provided at the tip of the hanging side wall portion of the outer belt-like material, it is possible to firmly prevent the entire tube from extending in the length direction while maintaining the state of being engaged with each other in a superposed manner. It is possible to maintain a stable form with almost no tensile force acting on the inner tube made of a soft synthetic resin.

  In the outer tube made of a hard material, the invention according to claim 2 forms the height of the hanging side wall portion of the outer belt-like material and the height of the rising side wall portion of the inner belt-like material as described above. However, as in the invention described in claim 3, even if the height of the hanging side wall portion of the outer belt-like material is different from the height of the rising side wall portion of the inner belt-like material, the same as above. An effect can be produced. Further, the hard material forming the outer tube may be a hard synthetic resin material or a metal material as described in claim 4, and when it is made of a hard synthetic resin material, extrusion molding is performed. The inner and outer belt-shaped members of the outer tube can be formed. When the inner and outer belt-shaped members are made of a metal material, the inner and outer belt-shaped members can be formed by bending a band plate having a constant width.

  According to the invention which concerns on Claim 5, since the inner peripheral surface of the said inner pipe is formed in the smooth surface of the same diameter over the full length, when it uses for a drain pipe, a water supply pipe, etc., smoothness of water As a matter of course, a spiral groove in which the bottom wall portion of the inner strip in the outer pipe is embedded is provided on the outer peripheral surface of the inner pipe, and the inner pipe between the spiral grooves is provided. The inner wall of the tube wall, i.e., between the spiral groove that has been wound once and the spiral groove that has been wound next, between the outer wall surfaces of the rising side wall portions of the adjacent inner belt members of the inner belt member. Since it is formed on the wall of the thick wall, it has a structure in which the weakest part of the inner pipe is reinforced by the wall thickness, and tensile, compressive, bending, and even large internal pressure acts on the pipe. However, the tube wall can be used for a long time without causing damage, breakage, or wrinkling.

The side view which carried out the cross section of some pressure-resistant pipes of this invention. The enlarged vertical side view of the part. The side view which carried out the cross section of a part of the state which curved the pressure | voltage resistant tube. The simplified side view which carried out the cross section of a part for demonstrating a manufacturing method. The one part expanded vertical side view which shows another Example of this invention pressure-resistant pipe | tube. The partial expanded vertical side view which shows another Example of this invention pressure-resistant pipe | tube.

  Next, a specific embodiment of the pressure tube of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a pressure tube partially cut away, and FIG. 2 is an enlarged vertical side view of a part of the pressure tube. The inner peripheral surface of the inner tube 1 is made of a soft synthetic resin formed on a smooth surface having the same diameter as the entire length, and the outer peripheral surface of the inner tube 1 is covered with the outer peripheral surface. An outer tube 2 made of a hard material is provided.

  As the soft synthetic resin material forming the inner pipe 1, a soft polyethylene resin, a polyolefin resin such as a polypropylene resin, or a resin material such as a polyvinyl chloride resin can be used. An inner pipe 1 is formed by continuously forming a spiral groove 3 having a constant width and a constant depth over the entire length at a constant pitch on the outer peripheral surface of a pipe wall having a constant thickness. Accordingly, the tube wall portion between the groove bottom of the spiral groove 3 and the inner peripheral surface of the inner tube 1 is formed in the thin tube wall portion 1a, while the tube between the spiral groove portions adjacent to each other in the length direction of the tube. The wall portion, that is, the spiral tube wall portion between the one-turn spiral groove portion 3a in the spiral groove 3 and the next one-turn spiral groove portion 3a adjacent to the spiral groove portion 3a becomes the thick tube wall portion 1b. Is formed.

  As the hard material forming the outer tube 2, a hard synthetic resin material such as a hard polyolefin-based resin or polyvinyl chloride resin, which is the same as the inner tube 1, is used. The outer tube 2 may be formed using a hard material. The outer tube 2 is formed on both side ends in the width direction of the strip-shaped bottom wall portion 4a having a constant width equal to the groove width of the spiral groove 3 of the inner tube 1 and outward from the both side ends. An inner strip 4 having a U-shaped cross-section that is formed by integrally forming rising side wall portions 4b and 4b having a constant height in a state of being refracted substantially at right angles to the bottom wall portion 4a, The rising side wall portion 4b of the inner strip-shaped member 4 is refracted at substantially right angles to the top wall portion 5a from both side ends inwardly from both side ends of the belt-like top wall portion 5a having a certain thickness. It is composed of an outer belt-shaped member 5 having a U-shaped cross section that is opened inward and formed by integrally forming hanging side wall portions 5b, 5b having a height substantially equal to 4b.

  Specifically, the inner strip 4 having a U-shaped cross section that opens outwardly is fitted into the spiral groove 3 of the inner tube 1 at the bottom wall portion 4a, and the spiral groove 3 and the spiral groove 3 are inserted into the spiral groove 3. The outer bottom surface of the spiral groove 3 is fixed to the groove bottom surface of the spiral groove 3 by fusing with the same pitch in a spiral shape, and the rising side walls 4b and 4b are outward from the spiral groove 3 perpendicular to the tube axis. It protrudes toward At the protruding ends, that is, at the tips of the both side rising side wall portions 4b, 4b, ridges 4c, 4c are protruded toward the inner wall surfaces facing these rising side wall portions 4b, 4b.

  On the other hand, the outer band member 5 having a U-shaped cross section that opens inwardly is formed between the rising side wall portions 4b and 4b of the adjacent inner band members 4 wound spirally on the inner tube 1. It is spirally wound at the same pitch as the inner strip 4 in a straddling state so that the side wall portions 5b, 5b on both sides can be brought into and out of contact with the inner wall surfaces of the rising side walls 4b, 4b of the inner strip 4 facing each other. And it is slidably engaged.

  Specifically, one rising side wall portion 4b of the belt-shaped material portion 41 wound in the spiral direction in the inner belt-shaped material 4 and the belt-shaped material portion 41 adjacent to this one-rolled inner belt-shaped material portion 41. The rising side wall part 4b facing the other side of the rising side wall part 4b of the inner belt-like material part 41 wound continuously from the other side, that is, through the thick pipe wall part 1b in the inner tube 1 4b, the top wall portion 5a of the outer belt-shaped member 5 is laid, and the inner surfaces of both end portions in the width direction of the top wall portion 5a are brought into contact with and received by the tips of the adjacent rising side wall portions 4b and 4b. In addition, the suspended side wall portions 5b, 5b are inserted into the inner strip-like material portions 41, 41 having a U-shaped cross section of the adjacent upward opening so as to straddle the rising side wall portions 4b, 4b. The opposing inner wall surfaces of the side wall portions 5b, 5b are overlapped with the inner wall surfaces of the rising side wall portions 4b, 4b, respectively. In addition, the ridge 5c protruding from the tips of the hanging side wall portions 5b, 5b is brought into contact with and slidable on the base end portion of the inner wall surface of the opposing rising side wall portion 4b.

  The width of the top wall portion 5a of the outer belt-shaped member 5 is the distance between one rising side wall portion 4b of the adjacent inner band-shaped material portions 41, 41 and the other rising side wall portion 4b opposite to the rising side wall portion 4b. Are formed wider than both side hanging side wall portions 5b, 5b projecting inward from both side ends thereof, and the opposite rising side wall portions 4b, 4b are sandwiched between the inner side wall surfaces of these hanging side wall portions 5b, 5b. Are opposed to the inner wall surfaces of the rising side wall portions 4b and 4b, respectively, and the ridges 5c and 5c are projected toward the rising side wall portions 4b and 4b opposite to the tips of the side wall hanging side wall portions 5b and 5b. The ridge 5c is slidably engaged with the proximal end portion of the inner wall surface of the rising side wall portion 4b facing each other as described above, while the ridge 4c provided at the tip of the rising side wall portion 4b is provided. Slide to the base end of the inner wall of the opposite hanging wall 5b It is not possible engaged.

  When a tensile force acts on the pressure tube constructed as described above in the length direction (axial direction) of the tube, the inner tube 1 is made of a soft synthetic resin and can be extended by pulling. In the outer tube 2 composed of the inner and outer belt-shaped members 4 and 5 that cover the outer surface of the inner tube 1, the bottom groove 4 a of the inner belt-shaped member 4 having an U-shaped cross section that opens outward is provided on the outer peripheral surface of the inner tube 1 The outer band member 5 having a U-shaped cross section that is fitted and fixed in the inner ring 3 and that opens inwardly is an inner band member part 41 wound around the inner tube 1 and the inner band member part. 41 is arranged in a state straddling the space between the inner belt-like material portions 41 wound in a single winding shape, and the side wall portions 5b, 5b on both sides thereof are adjacent to the inner belt-like material portions 41, 41 adjacent to each other. Are engaged with the rising side wall portions 4b and 4b facing each other via the protrusions 4c and 5c, respectively. The force is applied to the bottom wall portion 4a of the inner strip member 4 and the top wall portion 5a of the outer strip member 5 via the rising side wall portion 4b and the hanging side wall portion 5b which are engaged with each other, and the bottom wall portion 4a and the top wall portion 5a. However, since the inner and outer belt-shaped members 4 and 5 are formed of a hard material, they extend even when a tensile force is applied. Thus, the entire tube maintains a constant tube length without stretching.

  Furthermore, even if a compressive force acts on the pressure tube in the axial direction, the inner and outer strip members 4 and 5 that engage the rising side wall portions 4b and 4b and the hanging side wall portions 5b and 5b are connected to each other. It is prevented from contracting and can maintain a constant tube length.

  Further, when the pressure resistant tube is curved as shown in FIG. 3, a tensile force is generated on the outer tube wall side curved in a convex arc shape, while a compressive force is generated on the inner tube wall side curved in a concave arc shape. However, as described above, since the pressure-resistant tube hardly extends, the outer tube wall portion curved in a convex arc shape is spirally wound around the outer peripheral surface of the inner tube 1. A strip-shaped material portion 41 wound in a spiral in the spiral direction in the inner strip-shaped material 4 of the tube 2 and a strip-shaped material wound in a further wound form from the strip-shaped material portion 41 adjacent to the strip-shaped material portion 41. The rising side wall portions 4b, 4b facing the portion 41 are proximal end portions of the inner wall surfaces facing the both side hanging side wall portions 5b, 5b in the outer strip material 5 straddling between the strip material portions 41, 41. Tilted in the direction of approaching each other from the tip to the base, using the fulcrum as a fulcrum, and facing each other with the tilt The thick tube wall portion 1b of the inner tube 1 made of a soft synthetic resin interposed between the outer wall base portions between the raised side wall portions 4b and 4b is compressed and deformed, and the outer tube wall portion of the inner tube 1 is in a convex arc shape. In the outer tube 2, the outer belt-shaped member 5 straddling between the rising side wall portions 4 b and 4 b is formed on the rising side wall portions 4 b and 4 b facing the tips of the both side hanging side wall portions 5 b and 5 b. It curves along a convex arcuate curved surface while being slightly separated from the inner wall surface of the base end.

  On the other hand, in the inner tube wall portion curved in a concave arc shape, the inner tube wall portion of the flexible inner tube 1 is spirally wound around the outer peripheral surface of the inner tube 1 as it curves into the concave arc strip. The bottom wall portion 4a of the inner strip member 4 fluctuates in the tangential direction of the curved surface, and the adjacent rising strip portions 41b of the adjacent strip member portions 41, 41 facing each other across the thick tube wall portion 1b of the inner tube 1; 4b are mutually facing toward the tip with the tip ridges 5c and 5c of both side hanging side wall portions 5b and 5b of the outer belt-like member 5 engaged with the inner wall base end portions of the rising side wall portions 4b and 4b as fulcrums. Tilt in the approaching direction, the leading end ridges 4c, 4c of the rising side wall portions 4b, 4b are separated from the opposite inner wall base end portions of the both side hanging side wall portions 5b, 5b of the outer side band member 5, and the outer side band members Adjacent top wall portions 5a, 5a in the portion 5 are curved along a concave arcuate curved surface while narrowing the interval portion therebetween.

  At this time, the interval between the base portions of the rising side wall portions 4b and 4b of the adjacent band-like material portions 41 and 41 in the inner side band material 4 is the same as that in the outer side band material 5 straddling the rising side wall portions 4b and 4b. Since both side wall portions 5b and 5b hold the same interval as in the case of a straight pipe, almost no compressive force or tensile force acts on the above-mentioned thick tube wall portion 1b existing in this interval portion. Therefore, the inner pipe 1 can be kept smooth on its entire length without causing the inner pipe 1 to be damaged or wrinkled, and can flow smoothly during drainage or the like. . Further, an excellent crushing strength can be exhibited by the outer tube made of a hard material.

  Next, the manufacturing method of the flexible pressure-resistant tube configured as described above will be briefly described with reference to FIG. 4. First, a groove 31 having a constant width and depth is provided at the center in the width direction. As is well known, one of the preceding soft belt portions is formed on the molding rotating shaft 9 while extruding a soft strip material 10 made of a soft synthetic resin in a semi-molten state having a constant width and a constant thickness from a molding nozzle (not shown). The other end face of the soft strip material portion following the side end face is joined and fused together to be spirally wound at a constant pitch, so that the inner diameter is the same diameter over the entire length and the outer peripheral face is The spiral groove 3 is formed by continuously forming the groove 31 in the spiral direction, and the lower portion of the spiral groove 3 is a thin-walled tube wall 1a and a portion where no groove is provided is formed in the thick-walled tube wall 1b. As the tube 1 is formed, a hard synthetic resin is formed from another molding nozzle (not shown). A hard band with a U-shaped cross-section formed by protruding rising side wall portions 4b and 4b having a fixed height with protrusions 4c on the opposite surfaces of the tip toward the upper side at both ends of the bottom wall portion 4a having a certain width. An outer bottom surface of the bottom wall portion 4a is formed by spirally winding the material 40 on the inner tube 1 at the same pitch as described above so that the bottom wall portion 4a is fitted into the spiral groove 3 of the inner tube 1 while extruding the material 40. Is integrally fused to the groove bottom of the spiral groove 3, and the rising side wall portions 4b, 4b on both sides project outwardly from the spiral groove 3 onto the outer peripheral surface of the inner tube 1 and have an outwardly open U-shaped cross section. The inner strip 4 is continuously formed.

  Further, a ridge 5c on the tip-facing surface is directed downward from both side ends of the top wall portion 5a having a certain width made of a hard synthetic resin from another molding nozzle (not shown) following the inner band member 4. A strip-shaped material portion 41 spirally wound first in the inner strip-shaped material 4 while extruding a downward U-shaped hard strip-shaped material 50 formed by protruding hanging wall portions 5b, 5b having a certain height. And the top wall between the tips of the rising side wall portions 4b and 4b facing the strip-shaped material portion 41 that has been wound next to the strip-shaped material portion 41 with the thick-walled tube wall portion 1b of the inner tube 1 therebetween. By laying the part 5a and spirally winding it with the same pitch as the hard band member 40 with the side wall parts 5b and 5b on both sides straddling the rising side wall parts 4b and 4b, Adjacent strips of the inner strip 4 facing each other across the thick wall 1b of the tube 1 41 and 41 are continuously formed with outer band members 5 engaged with the inner wall surfaces of the rising side wall parts 4b and 4b in a state where the hanging side wall parts 5b and 5b are overlapped with each other. 5 is used to manufacture a pressure resistant tube in which a hard outer tube 2 is formed on an inner tube 1 made of a soft synthetic resin.

  In the above embodiment, as the inner tube 1 made of a soft synthetic resin, a spiral groove 3 having a constant width and a constant depth is provided on the outer peripheral surface of the tube wall, and a cross-sectional U-shape of the outer tube 2 is provided in the spiral groove 3. The bottom wall portion 4a of the inner belt-like material 4 is fused in a fitted state, but without providing such a spiral groove 3, the inner tube 1 is connected to the inner and outer circumferences as shown in FIGS. Even if the outer surface of the inner tube 1 is bonded to the outer peripheral surface of the inner tube 1 on the outer peripheral surface of the inner tube 1, the outer surface of the inner tube 1 is fused. Good.

  Further, in the outer tube 2 made of hard synthetic resin, the height of the hanging side wall portion 5b of the outer side strip member 5 having an U-shaped cross section that opens inward is substantially equal to the height of the rising side wall portion 4b of the inner side strip member 4. However, as shown in FIG. 5, the height of the rising side wall 4b of the inner band 4 is made shorter than the height of the hanging side wall 5b of the outer band 5, so that the inner band 4 While the protrusion 4c provided at the tip of the rising side wall portion 4b is slidably engaged with the intermediate portion in the length direction of the hanging side wall portion 5b of the outer strip 5 facing the rising side wall portion 4b in a superposed state. The protrusion 5c provided at the tip of the drooping side wall portion 5b of the outer band member 5 is engaged with the base end portion of the rising side wall portion 4b of the inner band member 4 facing the drooping side wall portion 5b in a superposed state. A pressure tube structure may be used.

  Further, as shown in FIG. 6, the height of the hanging side wall portion 5 b of the outer side band member 5 is made shorter than the height of the rising side wall portion 4 b of the inner side band member 4, so While the protrusion 4c provided at the tip is engaged with the base end portion of the hanging side wall portion 5b of the outer strip 5 facing the rising side wall portion 4b in a superposed state, it slides on the intermediate portion in the length direction While being freely engaged, the length of the ridge 5c provided at the tip of the hanging side wall portion 5b of the outer side band member 5 on the rising side wall portion 4b of the inner band member 4 facing the hanging side wall portion 5b in a superposed state. A pressure-resistant tube structure that is slidably engaged with an intermediate portion in the vertical direction may be used.

1 Inner tube 2 Outer tube 3 Spiral groove 4 Inner strip
4a Bottom wall
4b Rising side wall
4c Projection 5 Outer strip
5a Top wall
5b Hanging wall
5c ridge

Claims (5)

  It consists of an inner tube made of a soft synthetic resin and an outer tube made of a hard material, and the outer tube is integrally formed with rising wall portions of a certain height toward the outside on both sides of the bottom wall portion having a certain width. An inwardly-opening cross-sectional U-shape formed by integrally forming an inwardly-opening inner band-shaped member having a U-shaped cross-section and a side wall portion inwardly formed on both side ends of the top wall portion having a certain width. The outer strip is formed in a spiral shape with a constant winding pitch on the outer peripheral surface of the inner tube in a state where the bottom wall of the inner strip is fused to the inner tube. While being wound, the outer side band-like material is spirally wound at the same pitch as the inner side band-like material in a state where the outer side band-like material is straddled between the rising side wall parts of the adjacent inner side band-like materials. The flexibility is characterized by the fact that it is engaged with the inner wall surface of the rising wall of the material Pressure-resistant tube.   The height of the hanging side wall portion of the outer belt-like material and the height of the rising side wall portion of the inner belt-like material are formed to be substantially equal height, and can slide on the inner wall surface of the rising side wall portion at the tip of the hanging side wall portion. 2. The flexible protrusion according to claim 1, wherein an engaging protrusion is provided, and a protrusion that is slidably engaged with an inner wall surface of the hanging side wall is provided at a tip of the rising side wall. Pressure tube.   The height of the hanging side wall portion of the outer belt-like material and the height of the rising side wall portion of the inner belt-like material are different from each other, and slidably engages the inner wall surface of the rising side wall portion at the tip of the hanging side wall portion. 2. The flexibility according to claim 1, wherein a ridge that is slidably engaged with an inner wall surface of the hanging side wall portion is provided at a tip of the rising side wall portion. Having pressure tube.   The flexible tube according to claim 1, wherein the outer tube is made of a hard synthetic resin material or a metal material.   The inner tube is formed with a smooth surface of the same diameter over the entire length of the inner peripheral surface, and a spiral groove in which the bottom wall portion of the inner strip material in the outer tube is embedded in the outer peripheral surface, 2. The flexible tube according to claim 1, wherein the tube wall portion between the spiral grooves is formed on a thick tube wall portion interposed between the outer wall surfaces of the adjacent rising side wall portions of the inner strip member. Pressure tube.

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