JP2012111135A - Method for manufacturing hollow material, and thickness taking plate used therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a lightweight hollow material having high rigidity without wasting a manufacturing material.SOLUTION: The method for manufacturing the hollow material 10 having thick walled parts 11 provided to both end parts thereof and a thin-walled part 12 provided between them and integrated by fiber-reinforced plastic to become a structural material or a winding core includes a process (1) for arranging a plurality of thickness taking plates 30 for forming the thin-walled part 12 to the surface of a molding core 20, a process (2) for arranging an adhesion inhibiting material 31 to the surfaces of the respective thickness taking plates 30, a process (3) for attaching an uncured material of fiber reinforced plastic to the surfaces of the adhesion inhibiting material 31 and the molding core 20, a process (4) for curing the uncured material to form the hollow material 10 and pulling the molding core 20 out of the cured hollow material 10 and a process (6) for taking out at least the respective thickness taking plates 30 from a hole 10a from which the molding core 20 has been pulled out.

Description

The present invention is used for winding a hollow material as a structural material for supporting and supporting columns and support beams, or a relatively thin material of a flexible material such as a raw film, paper, or sheet. The present invention relates to a method for manufacturing a hollow material as a winding core, and a meat collection plate used for manufacturing the hollow material.

Structural materials for supporting and supporting columns and support beams are necessary for all kinds of materials, but it is necessary to have sufficient strength and rigidity as well as light weight. This is because the light structural material is important in improving workability in the installation work.

On the other hand, flexible materials such as raw film, paper or sheet are formed as very long materials, and in order to make these flexible materials into a certain product, they are wound up once. Is customary. In order to wind up a flexible material such as the original film, paper, or sheet, a hollow material is usually used as a tubular winding core. That is, the winding core is fixed to the end of a flexible material such as a long original film, paper, or sheet, and then the core is rotated to rotate the original film, paper, or sheet. It is used for the work of winding the flexible material, and plays an important role in winding and protecting the raw film. Then, the flexible material such as the original film, paper, or sheet is conveyed to a predetermined processing step while being wound around the core.

However, if the flexible material such as the original film, paper, or sheet becomes very thin or heavy as in recent years, only high rigidity is required for the core. In addition, when winding on a core prior to commercialization, considerable attention has been required to prevent wrinkling and tearing. Moreover, in the winding operation for the winding core, the winding core must be rotated at a high speed in order to improve efficiency.

The applicant has already made a proposal in Patent Document 1 as a method of manufacturing a hollow core as a core or a structural material that can withstand such high-speed rotation and heavy load support. Patent Document 2 also proposes a “fiber-reinforced thermosetting resin pipe” for bicycles.

Patent No. 4180554 publication Japanese Patent Laid-Open No. 06-278671, representative figure, paragraph 0017

In the method for manufacturing a hollow material proposed in Patent Document 1, for example,
`` A hollow material body comprising a hollow material used as a structural material and having a thick part located at both ends and a thin part located integrally with the entire inside of these thick parts, The manufacturing method including the following steps.
(1) A step of temporarily fixing a honeycomb sheet made of paper or a metal thin plate to the surface of the formed core bar except for the portion that becomes the thick portion;
(2) Winding inorganic fibers or synthetic fibers impregnated with resin, or prepregized inorganic fibers or synthetic fibers to be a plurality of winding layers on the formed core metal and honeycomb sheet at a predetermined inclination angle. Turning process;
(3) The step of drawing out the honeycomb sheet from the opening formed at the center of the thick part after extracting the cored bar after curing the fiber;
(4) A step of finishing the surface of the cured member. "
It is.

  The manufacturing method of the hollow material proposed in this Patent Document 1 has greatly contributed to the manufacturing of the applicant's hollow material up to now, but is made of “paper or metal thin plate” used in this manufacturing method. When the “honeycomb sheet” is “drawn from the opening formed at the center of the thick part”, the honeycomb sheet may be deformed or damaged, and may not be reusable in a short period of time.

  Patent Document 2 “Fiber-reinforced thermosetting resin pipe for bicycle frame and its manufacturing method” is “Lightweight, high-strength, constant outer diameter, thick at both ends and thick at the center. `` To provide a pipe made of fiber-reinforced thermosetting resin for a bicycle frame that has a thin shape and prevents the pipe inner diameter from expanding at the end of the pipe and at the same time has a maximum bending moment, and a manufacturing method thereof '' As described in FIG. 11 and paragraph 0017 of Patent Document 2, “After the matrix resin is cured, it is gradually cooled (as shown in FIG. 11 d) by a conventional method, Decore the metal mandrel 1. After decentering, scrape the self-releasing material 2 from the fiber reinforced thermosetting resin layer 4 (as shown in e of FIG. 11) with a suitable instrument or Use airflow, etc. , It is removed to obtain a fiber-reinforced thermosetting resin pipe bicycle frame of the present invention "is intended.

  That is, even in the technique of Patent Document 2, the “self-releasing material 2” is “scraped out by an appropriate instrument or removed using a water flow, an air flow or the like”. It cannot be used repeatedly.

  Therefore, the inventors of the present invention provide a new manufacturing method that allows reuse of materials used for manufacturing hollow materials over a long period of time while following the advantages of the manufacturing method proposed in Patent Document 1. As a result of various studies on what to do, the present invention has been completed.

  That is, the object of the present invention is to provide a method for producing a hollow material having high rigidity and light weight so that the material for production is not wasted, and a meat collection plate used for the method. There is.

In order to solve the above problems, first, the means taken by the invention according to claim 1 will be described with reference numerals used in the description of the best mode described below.
“A hollow material 10 comprising a thick part 11 at both ends and a thin part 12 between them and integrated with fiber-reinforced plastic to form a structural material or a core including the following steps. how to.
(1) The process of arrange | positioning the some meat picking board 30 which will form the said thin part 12 on the surface of the shaping | molding metal core 20;
(2) A step of disposing the adhesion preventing material 31 on the surface of each meat collection plate 30;
(3) A step of attaching the uncured material of the fiber reinforced plastic to the surface of the adhesion preventing material 31 and the cored bar 20;
(4) A step of curing the uncured material to form the hollow material 10;
(5) A step of extracting the molding core 20 from the cured hollow material 10;
(6) The process of taking out at least each said meat picking board 30 from the hole 10a from which the said shaping | molding metal core 20 was extracted. "
It is.

  As shown in FIGS. 1A to 1C, the hollow material 10 that is the object of the production method of the present invention is integrated with fiber reinforced plastic, and has thick wall portions 11 at both ends, and these It consists of the thin part 12 between. As shown in FIG. 1C, a connecting plate 14 for attaching the hollow material 10 to the rotating device is attached to the end of each thick portion 11, and rotational force is applied via the connecting plate 14. In some cases, the thick portions 11 are literally thicker than the thin portions 12 to increase the rigidity. On the other hand, the thin portion 12 is thinner than the thick portion 11 in order to reduce the weight of the entire hollow material 10.

  Such a hollow material 10 is formed by the method of claim 1. First, in step (1), as shown in FIG. 2, the thin portion 12 is formed on the surface of the molded core 20. A plurality of meat collection plates 30 to be performed are arranged. These meat collection plates 30 are divided as will be described later, and if the cored bar 20 is cylindrical, it is difficult to completely dispose it on the surface. As shown by the phantom line, it is good to temporarily fix using the adhesive tape etc. until it arrange | positions the contact | adherence prevention material 31 mentioned later.

As shown in FIG. 4, when the plurality of the meat collecting plates 30 are completely arranged on the surface of the molded core bar 20, the whole shape becomes a cylindrical shape fitted to the molded core bar 20. And substantially coincides with the shape of the meat removal space 13 of the hollow member 10 shown in FIG. Further, since these meat collecting plates 30 are unnecessary for the completed hollow member 10, they must be taken out from the hole 10a of the hollow member 10, so that as shown in FIG. 2 and FIG. 10a is divided into sizes that make it easy to take out.

In the step (2), as shown in FIG. 5, the adhesion preventing material 31 is disposed on the surface of each meat collecting plate 30. In order to facilitate the work in this step (2), the adhesion preventing material 31 As 31, it is good to apply | coat the adhesive material by the continuous length in the shape of a tape, or what can be apply | coated simply. In addition, if the adhesive tape etc. which were used for temporary attachment at the time of arrangement | positioning of each meat picking board 30 are not useful as the adhesion prevention material 31, it is good to remove this. The adhesive tape as the adhesion preventing material 13 may be temporarily fixed by using the adhesive tape as the adhesion preventing material 13, and thereafter, the adhesive tape as the adhesion preventing material 31 may be disposed on the entire meat removal plate 30.

  This adhesion prevention material 31 is used to prevent adhesion or adhesion between the inner surface of the thin portion 12 of the hollow material 10 formed by curing the fiber reinforced plastic and each of the meat collection plates 30, and is a completed hollow. If the material 10 is unnecessary, it is taken out from the hole 10a of the hollow material 10 later as shown in FIG. Of course, in the case where the adhesion preventing material 31 is a thin film-like material applied on each of the meat collecting plates 30 and does not cause any problem even if it remains on the inner surface of the thin portion 12 of the completed hollow material 10. No need to take out.

    Then, in the step (3), an uncured material of fiber reinforced plastic is applied to the adhesion preventing material 31 disposed on the meat collection plate 30 and the surface of the molding core 20 exposed on the left and right of the meat collection plate 30. In the step (4), the uncured material is cured to form a hollow material 10 that has been cured.

  There are various uncured fiber reinforced plastics as exemplified in the above-mentioned Patent Document 1 and the embodiments described later, and there is also a method of attaching the uncured fiber reinforced plastic to the surface of the meat plate 30 or the like. There are various types as described in Patent Document 1 and an embodiment described later, and FIG. When the fiber reinforced plastic disposed on the surface of the meat collection plate 30 or the like is cured as described above, the state shown in the cross-sectional view of FIG. 7 is obtained.

  In step (5), the cored bar 20 is extracted from the hollow material 10 cured as described above, as illustrated in FIG. If the molded core 20 is extracted, a hole 10a is formed at the end of the hollow member 10 as shown in FIG. In order to facilitate the work of extracting the formed cored bar 20, the adhesion preventing material 31 or the release agent may be applied to the surface of the formed cored bar 20 before the step (2).

  Finally, in the step (6), at least each of the meat collecting plates 30 is taken out from the hole 10a from which the forming metal core 20 has been extracted. In this case, since each of the meat collecting plates 30 is attached to the inner surface of the thin portion 12 via the adhesion preventing material 31, it is removed from the adhesion preventing material 31 with a tool inserted through the hole 10a. Since the blocking material 31 does not adhere to each of the meat collection plates 30 or the fiber reinforced plastic, it can be easily removed as shown in FIG. Further, since each of the meat collection plates 30 is divided into a plurality of parts, the vertical width shown in FIG. 3B is smaller than the diameter of the hole 10a, and the hollow material of each of the meat collection plates 30 is The take-out from the inside 10 can be easily performed as shown in FIG.

  In the hollow material 10 (particularly the inner surface of the thin wall portion 12) after removing the meat removal plates 30, the adhesion preventing material 31 remains as shown in FIG. 9, but the “film” to which the adhesion preventing material 31 is applied. Instead, if it is an “object” such as an adhesive tape, it is pulled out from the hole 10a and removed as shown in FIG. This means that “at least each meat collection plate 30 is taken out”.

  The hollow material 10 is completed by the above steps, but if necessary, the connection plate 14 as shown in FIG. 1C is attached and the surface of the hollow material 10 is subjected to final polishing.

  Here, since each meat removal board 30 is peeled from the adhesion preventing material 31 on the inner surface of the hollow material 10 formed by curing the fiber reinforced plastic, the adhesion preventing material 31 prevents adhesion and adhesion. It is peeled off with almost no deformation or breakage. And since the said meat picking board 30 is divided | segmented into the state which can be taken out from the hole 10a of the hollow material 10, when taking out from the inside of the hollow material 10, damage is given to the hollow material 10 and the meat picking board 30 itself. There is nothing.

  As a result of the above, each meat collection plate 30 can be used sufficiently when the next hollow member 10 is manufactured, and the hollow member 10 can be manufactured without waste.

  Therefore, according to the first aspect of the present invention, the hollow material 10 having high rigidity and light weight can be reliably manufactured, and the meat collecting plate 30 which is a manufacturing material can be reused for a long period of time. This is a production method that does not waste production materials.

In order to solve the above problem, the means taken by the invention according to claim 2 is:
“Thick parts 11 at both ends and thin parts 12 between them are integrated by curing an uncured fiber reinforced plastic that is attached to the surface of the cored bar 20 to form a structural material or winding It is a meat collection board 30 that has been divided into three or more parts, which is used in manufacturing the hollow material 10 as a core,
The space formed by the extension surface of the inner surface of the thick portion 11 and the inner surface of the thin portion 12 has a shape divided into at least three or more divisions along a line segment along the axial direction of the forming core 20,
When placed on the surface of the cored bar 20, the meat collecting plate 30 that can wrap the entire peripheral surface of the molded cored bar 20 except for the thick portion 11.
It is.

  That is, the meat collection plate 30 according to claim 2 is used for carrying out the method for manufacturing the hollow member 10 according to claim 1, and includes an extended surface of the inner surface of the thick part 11 of the hollow member 10. The space formed by the thin-walled portion 12 inner surface of the hollow member 10, that is, the meat-removal space 13, has a shape divided into at least three or more divisions along a line segment along the axial direction of the cored bar 20. In other words, this meat collection board 30 can be used for the said manufacturing method of the hollow material 10 by preparing only the divided | segmented number.

  Each meat collection plate 30 does not adhere to the hollow material 10 due to the presence of the adhesion preventing material 31, and has a shape that can be easily taken out from the hole 10 a of the cured hollow material 10 by being divided. Therefore, the material constituting this is not particularly limited. That is, the meat collection plate 30 may be formed of a metal plate or wood, but in the embodiment described later, the same fiber reinforced plastic as that constituting the hollow member 10 is employed.

The shape of each meat collecting plate 30 is divided into at least three or more divisions along the axial center direction of the molding core 20 of the meat sampling space 13 in FIGS. 2 and 3. As shown, if the entire core used for manufacturing the hollow material 10 is brought into contact with the outer peripheral surface of the molded core 20, the inner surface of the molded core 20 is in contact with the outer peripheral surface without any gap. It means that it becomes a cylindrical thing fitted to the outer periphery.

In addition, it is necessary to divide each meat collection plate 30 by a line segment along the axial direction of the cored bar 20 of the meat removal space 13 from the hole 10 a of the hollow material 10. This is because it must be taken out. In that sense, even if each of the meat collecting plates 30 is divided into two by one line segment as shown in FIG. Since it can take out from each hole 10a of both ends, the beef plate 30 divided | segmented by the line segment along the axial center direction of the shaping | molding metal core 20 is made into one line segment along the radial direction of the shaping | molding metal core 20. It may be further divided.

Further, the reason why the meat collecting plates 30 need to be divided into at least three or more divisions is that the meat collecting plates 30 must be taken out from the holes 10 a of the hollow material 10. If each meat collection plate 30 becomes a “cylindrical shape” as shown in FIGS. 2 and 3 when used in the method of manufacturing the hollow material 10, the hole 10 a of the hollow material 10 is circular. However, in order to be able to take out each of the meat collecting plates 30 from the circular hole 10a, the vertical width of each of the meat collecting plates 30 shown in FIG. 3B needs to be smaller than the diameter of the hole 10a. If these meat collection plates 30 are divided into at least three divisions, the vertical width of each meat collection plate 30 is smaller than the diameter of the hole 10a.

Since each meat collection board 30 comprised as mentioned above is a thing in which adhesion | attachment and adhesion | attachment are blocked | prevented by the adhesion | attachment prevention material 31, when using it with the manufacturing method of the hollow material 10 of Claim 1, fiber reinforced plastics are used. There is almost no deformation or breakage when peeled off from the adhesion preventing material 31 on the inner surface of the hollow material 10 formed by curing. And since the said meat picking board 30 is divided | segmented into the shape which can be taken out from the hole 10a of the hollow material 10, when taking out from the inside of the hollow material 10, damage to the hollow material 10 and the meat picking board 30 itself is carried out. It is never given.

  Therefore, the meat collection plate 30 according to the second aspect can be sufficiently utilized when the hollow member 10 is manufactured, and the hollow member 10 can be manufactured without waste.

As described above, in the invention according to claim 1,
“A hollow material 10 comprising a thick part 11 at both ends and a thin part 12 between them and integrated with fiber-reinforced plastic to form a structural material or a core including the following steps. how to.
(1) The process of arrange | positioning the some meat picking board 30 which will form the said thin part 12 on the surface of the shaping | molding metal core 20;
(2) A step of disposing the adhesion preventing material 31 on the surface of each meat collection plate 30;
(3) A step of attaching the uncured material of the fiber reinforced plastic to the surface of the adhesion preventing material 31 and the cored bar 20;
(4) A step of curing the uncured material to form the hollow material 10;
(5) A step of extracting the molding core 20 from the cured hollow material 10;
(6) The process of taking out at least each said meat picking board 30 from the hole 10a from which the said shaping | molding metal core 20 was extracted. "
There is a feature in the structure, and this makes it possible to reliably manufacture the hollow material 10 that is both rigid and light, and of course, the meat plate 30 that is a manufacturing material can be reused for a long period of time. Thus, the hollow material 10 can be manufactured without generating waste in the manufacturing material.

In the invention according to claim 2,
“Thick parts 11 at both ends and thin parts 12 between them are integrated by curing an uncured fiber reinforced plastic that is attached to the surface of the cored bar 20 to form a structural material or winding It is a meat collection board 30 that has been divided into three or more parts, which is used in manufacturing the hollow material 10 as a core,
The space formed by the extension surface of the inner surface of the thick portion 11 and the inner surface of the thin portion 12 has a shape divided into at least three or more divisions along a line segment along the axial direction of the forming core 20,
When arranged on the surface of the molded core 20, the entire peripheral surface of the molded core 20 except the thick portion 11 can be wrapped.
Therefore, not only can it be sufficiently utilized as a material for producing the hollow material 10, but also it can be reused, and the hollow material 10 can be produced without waste.

The hollow material 10 which is a manufacturing object by the method of this invention is shown, (a) is the side view of the hollow material 10 which made the left half a cross section, (b) is a front view, (c) attaches the connection board 14 1 is a perspective view of a hollow material 10. FIG. 3 is a perspective view showing a state in which a plurality of meat collection plates 30 are going to be arranged around a molded core bar 20. The number of the meat collecting plates 30 used for manufacturing the hollow material 10 is shown, (a) is a side view, (b) is a front view, and (c) is a partially enlarged side view of (a). FIG. 3 is a perspective view of a state in which all the meat collecting plates 30 are arranged around the molded core bar 20. FIG. 3 is a perspective view of a state where an adhesion preventing material 31 is about to be disposed on the meat collection plate 30. FIG. 4 is a partial perspective view showing the order in which the materials and materials are arranged on the molded core bar 20. It is a longitudinal cross-sectional view which shows the hollow material 10 before hardening of a fiber reinforced plastic or after hardening. 2 is a partially broken side view showing a state where a molded cored bar 20 is extracted from a hollow material 10. FIG. It is a partially broken side view which shows a mode that the meat picking board 30 is extracted from the hole 10a. It is a partially broken side view which shows a mode that the adhesion | attachment prevention material 31 which needs to be taken out from the hole 10a is taken out. It is sectional drawing which shows the manufacturing method of patent document 2 in order of (a)-(e).

  Next, the invention according to each claim configured as described above will be described according to the embodiment shown in the drawings. In each drawing, the manufacturing method is mainly shown step by step. The meat collection plate 30 according to claim 2 is used in this manufacturing method, and will be described while explaining the manufacturing method.

1 (a) to 1 (c) show a hollow material 10 which is an object of the manufacturing method according to the present invention. This hollow material 10 is integrally formed of fiber reinforced plastic and has both end portions. The thick part 11 and the thin part 12 between them. In the present embodiment, a connecting plate 14 for attaching the hollow material 10 to the rotating device is attached to the end of each thick part 11 as shown in FIG. The connecting plate 14 serves as a “chucking portion” for applying a rotational force from the rotating device to the hollow material 10 through the connecting plate 14. The thickness is made thicker than that of the thin wall portion 12 so that the rigidity is increased. On the other hand, the thin portion 12 positioned between these thick portions 11 is thinner than the thick portion 11 in order to reduce the weight of the entire hollow material 10.

  Moreover, in this hollow material 10, as a result of forming the thin wall portion 12 between the thick wall portions 11 at both ends, as shown in FIG. A meat removal space 13 is formed. The meat removal space 13 is formed by a surface obtained by extending the inner surface of the thick portion 11 and the inner surface of the thin portion 12. In the cylindrical hollow material 10 according to this embodiment, the cylindrical space is a cylindrical space. It has become.

  Here, in this embodiment, as shown in FIG. 6, the hollow material 10 is mainly composed of a first winding layer 16, a second winding layer 17, and a base material layer 15 as necessary. The coating layer 18 is formed as necessary. FIG. 6 shows a state in which the cored bar 20 is inserted for the sake of explanation, but the molded cored bar 20 is removed after the hollow material 10 is completed. It is not a component of the hollow material 10 manufactured by the manufacturing method.

  Further, as the uncured material of the fiber reinforced plastic, in addition to the fiber yarn, tape, and cloth constituting the first winding layer 16 and the second winding layer 17 and the resin impregnated therein, tape, cloth Also, a so-called “prepreg” in which the resin impregnated therein is made into a semi-cured state, a so-called “tuprepreg” in which the fiber yarn and the resin impregnated therein are made into a semi-cured state can be employed. As a constituent material of the base material layer 15, a so-called “prepreg” in which a tape, a cloth, and a resin impregnated therein are semi-cured in addition to a tape, a cloth and a resin impregnated therein can be employed. In addition, as in the case of Patent Document 1, carbon and glass are used as constituent materials for fiber yarns and cloths.

  Now, the above hollow material 10 is formed using the meat collection board 30 shown in FIG. As shown in FIG. 4, when the plurality of the meat collecting plates 30 are completely arranged on the surface of the forming core bar 20, the whole shape becomes a cylindrical shape fitted to the forming core bar 20. This is substantially the same as the shape of the meat removal space 13 of the hollow member 10 shown in FIG. In addition, since the hollow material 10 of this embodiment has the step part 13a formed in the inner end of the meat removal space 13 as shown to (a) of FIG. 1, it shows to (c) of FIG. As described above, a stepped portion 30 a is formed in a corresponding portion of each meat collection plate 30.

  As shown in FIGS. 2 and 4, the above-described meat collection plate 30 is disposed on the surface of the formed cored bar 20. As shown, the adhesion preventing material 31 or the release agent is arranged or applied so that the cored bar 20 can be easily extracted from the meat collection plates 30 and the completed hollow material 10. . Of course, as shown in the phantom lines in FIG. 4, in order to prevent each of the meat collecting plates 30 from being scattered when or after the arrangement of each of the meat collecting plates 30 on the molded core bar 20, It is advisable to make a temporary stop.

  As shown in FIG. 5, the adhesion preventing material 31 is arranged on each meat collection plate 30 arranged as described above. The adhesion preventing material 31 in the present embodiment is a “tape-like” long one for facilitating its placement work and removal after use. Of course, the adhesion preventing material 31 is not limited to a tape-like material. In short, if the adhesion to the back surface of the thin portion 12 of each meat collecting plate 30 can be prevented, what is used as the adhesion preventing material 31? Is also good. Moreover, the adhesive tape as the adhesion preventing material 31 may be used for temporary fixing, and thereafter, the adhesive tape as the adhesion preventing material 31 may be arranged on each whole meat collecting plate 30.

  Then, uncured fiber reinforced plastic is disposed on the cored bar 20 exposed from the adhesion prevention member 31 and the meat collection plate 30 as shown in FIG. As described above, the material and arrangement method of the fiber reinforced plastic may be anything. In this embodiment, since it is assumed that the hollow material 10 is manufactured in a cylindrical shape, the fiber-reinforced plastic includes the first winding layer 16 and the second winding layer 17 formed by a so-called “winding method”. Try to form. In order to form the inner surface of the hollow member 10 smoothly, the base material layer 15 may be employed on the inner surface of the first winding layer 16. Further, in order to give the outermost layer of the hollow material 10 smoothness and conductivity, a coating layer 18 is adopted as the outermost layer, and this coating layer 18 is formed after the fiber reinforced plastic is cured. ing.

  The above fiber-reinforced plastic is heated in the heating device together with the molded core 20 and each of the meat collecting plates 30 to be cured and become the hollow material 10. Although the state is shown in FIG. 7, in order to complete this hollow material 10, first, as shown in FIG. 8, the shaping | molding metal core 20 is extracted.

  If the formed core bar 20 is extracted, since the holes 10a are opened at both ends of the hollow member 10 as shown in FIG. 9, the above-described meat picking plates 30 and the adhesion preventing member 31 are extracted through the holes 10a. is there. Since each of the meat collecting plates 30 is not in close contact with the inner surface of the thin portion 12 by the adhesion preventing material 31, it can be easily removed, and since the meat collecting plate 30 is divided, it can be easily taken out from the hole 10a. Of course, the adhesion preventing material 31 itself can be easily taken out as shown in FIG.

  It goes without saying that each meat collection plate 30 taken out as described above has almost no damage, and can be reused in the next step for manufacturing another hollow material 10.

DESCRIPTION OF SYMBOLS 10 Hollow material 10a Hole 11 Thick part 12 Thin part 13 Meat taking space 13a Step part 14 Connection board 15 Base material layer 16 1st winding layer 17 2nd winding layer 18 Coating layer 20 Molding core 30 Meat take board 30a Step part 31 Adhesion prevention material

Claims (2)

A method of producing a hollow material which is composed of a thick part at both ends and a thin part between them and is integrated with a fiber reinforced plastic to be a structural material or a core including the following steps.
(1) The process of arrange | positioning the several meat picking board which will form the said thin part on the surface of a shaping | molding metal core;
(2) A step of disposing an adhesion preventing material on the surface of each meat-removing plate;
(3) A step of attaching an uncured material of the fiber reinforced plastic to the surface of the adhesion preventing material and the cored bar;
(4) A step of curing the uncured material to form the hollow material;
(5) A step of extracting the molded core from the cured hollow material;
(6) The process of taking out at least each said meat picking board from the hole from which the said forming metal core was extracted. A hollow that is composed of a thick part at both ends and a thin part between them, and is integrated by curing an uncured fiber reinforced plastic that is attached to the surface of the cored bar to become a structural material or a core It is a meat collection board that has been divided into three or more parts, which is used in manufacturing the material,
The space formed by the extended surface of the thick-walled inner surface and the inner surface of the thin-walled portion has a shape divided into at least three divisions along a line segment along the axial center direction of the cored bar,
A meat collecting plate that can be wrapped around the entire peripheral surface of the molded cored bar except for the thick-walled part when placed on the surface of the molded cored bar.

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