JP2018178576A - Sheath connecting pipe for protecting pc steel material and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sealing performance while securing ease of screwing a PC steel material protective sheath.SOLUTION: In a resin-made PC steel material protective sheath connecting pipe 1 for connecting a PC steel material protective sheath 6 molded into a helical concavo-convex shape into which PC steel material is inserted and grout is injected, a ring-shaped sealing member 5 which is inflatable is integrally formed by absorbing the liquid at a position spaced from the edge portion of a connection side end portion 4 to which the PC steel material protective sheath 6 is connected.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a connecting pipe for connecting a PC steel material protecting sheath for protecting PC steel material used at the time of construction of prestressed concrete (hereinafter, also referred to as PC) and a method of manufacturing the same.

  Conventionally, there is known a method in which the concrete is prevented from cracking as much as possible by applying a compressive stress to the concrete in advance. In order to introduce prestress to concrete, high strength cables called PC steel are used. When the PC steel is pulled and tensioned and then fixed to the concrete, the tension is applied to the concrete as the pulled PC steel returns. As a method of introducing pre-stress, a pre-tension method in which tension is applied before pouring concrete and a post-tension method in which tension is applied after pouring are known.

  Then, it is known that the PC steel is protected by a protective sheath of a resin material so that the PC steel does not directly touch concrete, and the sheath is filled with a hardening agent (grout) such as mortar. The protective sheath is formed in a helical pattern to prevent axial movement of the concrete and grout sheath.

  In the sheath connection tube for PC steel material protection which connects the sheath for PC steel material protection, if there is a gap in the connection part with the sheath, grout filled in the sheath leaks out of the sheath, conversely, water outside the sheath is sheath There is a problem of infiltrating inside.

  Therefore, for example, in a prestressed structure such as Patent Document 1, a sheath into which PC steel is inserted and in which a filler is filled, a connection member connected to the sheath, and a connection portion between the sheath and the connection member And an expandable body which can be brought into intimate contact with the sheath and the connecting member by the expansion accompanying the absorption of liquid. This expandable body is known to be constituted by a non-woven fabric containing a material capable of absorbing a liquid.

  On the other hand, as in Patent Document 2, an annular lower layer material is inserted and held on the peripheral surface of the core material provided at the center, and then a parison is supplied to the outer periphery of the lower layer material to make the core shape material and the lower layer material parison. After covering, the mold is clamped except for a part of the molding surface of the mold, and then the movement of the moving member provided on the mold forms a part of the remaining molding surface, so that at least two layers are formed. There is known a manufacturing method for forming an annular body laminated on the. In this manufacturing method, a spiral groove is formed on the circumferential surface of the core member, and a spiral convex portion inserted and arranged in the spiral groove is formed on the inner surface of the mold and the moving member. A helical groove is formed on the outer peripheral surface of a certain annular body, and a helical convex portion is formed on the inner peripheral surface of the annular body.

Patent No. 4404933 (Especially FIG. 1 and FIG. 3) Patent No. 3723538 gazette

  However, in the sheath for protecting PC steel material of Patent Document 1, the end portion of the seal member made of an expandable body is configured to protrude from the end portion of the sheath, so when the sheath is screwed in, the seal member is caught. There is a problem that it is difficult to connect the sheath. In addition, extra work of winding the protruding part of the seal member with a tape or the like is also required.

  In addition, when a non-woven fabric capable of absorbing liquid is attached to the entire inner surface of the connection tube as in Patent Document 2, the material cost is increased and the sheath is difficult to be screwed.

  The present invention has been made in view of the above point, and an object thereof is to improve sealing performance while securing the ease of screwing in a sheath for protecting PC steel material.

  In order to achieve the above object, in the present invention, an expandable ring-shaped seal member is integrally formed on the inner peripheral surface at a position spaced from the edge by absorbing the liquid.

Specifically, in the present invention, a sheath connection pipe for protecting a PC steel material for connecting a PC steel protection sheath molded into a helical uneven shape into which PC steel is inserted and grout is injected. Assuming that
At least one side has an inner circumferential surface engageable with the concavo-convex shape of the outer circumferential surface of the sheath for protecting the PC steel material, and an inner circumferential side of the connection side end to which the sheath for protecting the PC steel steel is connected A ring-shaped seal member capable of absorbing liquid and expanding at a position spaced apart from the portion is integrally formed.

  According to the above configuration, since the seal member is integrally formed at the connection side end portion of the sheath connection tube for protecting PC steel material with a gap from the edge, when inserting and connecting the sheath for protecting PC steel material, the edge portion It is difficult to get in because there is no seal member and it is easy to connect. And, since the seal member is integrally formed, the seal member is unlikely to come off. Moreover, since it is integral molding, there is no troublesome work, such as bonding a sealing member later. Furthermore, since the seal member is provided on the inner side, the appearance does not change. In addition, although "ring shape" means cyclic | annular and includes the cylindrical shape which has a width | variety to some extent, a sealing member is not provided in the whole inner surface of a sheath connection pipe | tube for PC steel material protection.

A second invention relates to the first invention,
The seal member is a non-woven fabric, and the non-woven fabric is welded and integrated.

  According to the above configuration, since the non-woven fabric is welded to the inner surface and integrated, the non-woven fabric is difficult to peel off when the PC steel protective sheath is screwed in, and the sealing performance is easily secured.

In the third invention, a method of manufacturing a sheath connecting pipe for protecting a PC steel material for protecting a PC steel material for connecting a PC steel protection sheath formed into a helical uneven shape into which PC steel is inserted and grout is injected. Assuming that
The PC steel material is protected by insert molding a ring-shaped seal member capable of absorbing liquid and expanding at a position spaced from the edge on the inner surface side of the connection side end to which the PC steel material protective sheath is connected The inner peripheral surface which can be engaged with the outer peripheral surface of the sheath is formed.

  According to the above configuration, since the seal member can be insert-molded and welded at the time of molding the sheath connection tube for protecting PC steel material, manufacture is easy as compared with the case where the seal member is bonded to a predetermined position after molding. Securely fixed to the inner surface.

  As described above, according to the present invention, a ring-shaped seal member expandable by liquid is formed on the inner surface of the connection side end portion to which the sheath for protecting PC steel material is connected and at a distance from the edge portion. By integral molding, the sealability can be improved while securing the ease of screwing in the sheath for protecting PC steel material.

It is the II sectional view taken on the line of FIG. 2 which shows the sheath connection pipe for PC steel material protection which concerns on embodiment of this invention. It is a front view showing a sheath connection pipe for PC steel material protection concerning an embodiment of the present invention. It is the III section enlarged sectional view of FIG. It is the FIG. 1 equivalent sectional view which shows the sheath connection pipe | tube for PC steel materials protection of the state which connected the sheath for PC steel materials protection to both ends. It is a front view which shows 1 process of the manufacturing method of a sheath connection pipe for PC steel material protection. It is a top view which shows 1 process of the manufacturing method of the sheath connection pipe for PC steel material protection.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

-Configuration of sheath connection tube for protecting PC steel-
FIG. 1 shows a sheath connection pipe 1 for protecting PC steel material according to an embodiment of the present invention. The sheath connection pipe 1 for protecting PC steel material is, for example, a molded article of polyethylene resin as a base material. The sheath connection tube for protecting PC steel material 1 has a substantially cylindrical cross section in which a helical uneven shape is formed, and as shown by a two-dot chain line in FIG. It has become so. Although not shown in detail, the PC steel is inserted inside the PC steel protection sheath 6 connected to the both ends, and the grout is injected in a tensioned state of the PC steel. There is. In addition, the synthetic resin material used as a base material is not specifically limited. The PC steels are made of known PC steel wires, PC steel strands, PC steel rods and the like.

  In the sheath connecting pipe 1 for protecting PC steel material, the convex strip 2 protruding outward in the radial direction is formed in a spiral shape, and a flat cylindrical portion 3 is formed in the central portion in the longitudinal direction. The ridges 2 are spirally provided on at least both sides of the cylindrical portion 3. Thus, on the inner surface 2a of the area where the ridge 2 of the PC steel protection sheath connecting tube 1 is present, a spiral unevenness (groove) engaged with the outer peripheral surface of the PC steel protection sheath 6 is formed. . In addition, the convex part 2 may be provided in the whole, without the cylindrical part 3.

  Then, at the connection side end 4 to which the PC steel protection sheath 6 is connected, a ring-shaped seal member 5 capable of absorbing the liquid and expanding on the inner surface 2a side at a position spaced a distance L1 from the edge is integrated. It is molded. The seal member 5 is made of, for example, a non-woven fabric having a thickness of 2 mm, to which water-expandable particles adhere. And this non-woven fabric is welded and integrated with the base material of polyethylene resin. For example, in the case of the seal member 5 having an outer diameter of about 80 mm and a thickness of about 2 mm for the sheath 6 for PC steel material protection, the width L2 of the seal member 5 is 30 mm, and the distance L1 from the edge is 15 mm. The values of L1 and L2 may be larger or smaller than this, and the thickness of the non-woven fabric is not particularly limited, but when it is too thick, the workability deteriorates when the PC steel protective sheath 6 is screwed.

  As described above, in the present embodiment, since the seal member 5 made of non-woven fabric is welded and integrated with the inner surface 2a of the base material, the non-woven fabric is not easily peeled off when the PC steel protective sheath 6 is screwed in. Easy to secure. When the PC steel protective sheath 6 is screwed in, as shown in FIG. 4, for example, a non-woven fabric having a thickness of 2 mm is compressed to a thickness of about 1 mm.

  The sheath connection tube 1 for protecting PC steel material described above is formed by the forming apparatus 10 and the manufacturing method of the annular body of the present invention described below.

-Configuration of forming apparatus of sheath connection tube for protecting PC steel-
FIG. 5 shows a schematic configuration of the molding apparatus 10, which is formed on the left and right molds 11, 12, the core material 13 provided between the molds 11, 12, and above the core material 13. A parison supply device 14 is provided, which supplies a parison 1 'between the core member 13 and the molds 11, 12. The molds 11 and 12 are provided so as to be movable left and right respectively by moving means such as hydraulic cylinders (not shown), and the mold opening and the mold clamping are performed based on the core member 13 and the parison supply portion 14 a of the parison supply device 14. Is to be done. As shown in FIG. 6, when the molds 11 and 12 are clamped, the respective inner peripheral surfaces 11a and 12a are processed such that a cylindrical opening as a whole is formed in the central portion thereof. The convex portions 11 b and 12 b are formed on the circumferential surfaces 11 a and 12 a so as to form a continuous spiral as a whole.

  As described above, a part of the mold 11 forming the opening is constituted by the slide member 11c as shown in FIG. The slide members 11 c are provided in a pair at the front and back of the mold 11, and extend and contract between a molding position where an opening is formed by the molds 11 and 12 and a separation position where the mold 11 expands laterally. It is slidably configured by an actuator such as a cylinder or a motor. The core member 13 is formed in a cylindrical shape slightly smaller than the opening, and on the outer peripheral surface thereof, the groove portion 13a into which the inner surface side of the convex portions 11b and 12b is inserted when the molds 11 and 12 are clamped. Are provided spirally over the top and bottom.

  Therefore, when the molds 11 and 12 clamp the core mold 13 between them, a cavity corresponding to the sheath connecting pipe 1 for protecting the PC steel material is formed between the molds 11 and 12 and the core 13. Part) is formed.

  A groove 13a having a shape corresponding to the ridges 2 is formed in the core member 13, and the seal member 5 made of a non-woven fabric formed in a ring shape at the time of forming the sheath connection tube 1 for protecting PC steel is its outer periphery Holding means are provided which fit and hold on the surface. In the holding means, a plurality of ventilating holes 13b are formed on the surface of the core 13 corresponding to the insert position of the seal member 5, and inside the core 13 a communicating passage (shown in FIG. The suction / blowing device 16 provided outside is connected to the communication passage via a hose 16a.

  The suction / blowing device 16 is configured to be able to suck air from the air vent 13b to the inside thereof, and conversely to send air from the apparatus side to the air vent 13b. Therefore, the suction and blowing device 16 is operated in a state where the seal member 5 is inserted, and the air is sucked through the air vent 13 b to adsorb and hold the seal member 5 at a predetermined position on the outer peripheral surface of the core material 13. Can.

  Further, a chuck device (not shown) is provided near the lower end of the core 13 to grip the lower end of the parison 1 'at the lower end of the core 13 when the entire outer periphery of the core 13 is covered by the parison 1'. There is.

  The parison supply device 14 supplies a parison 1 'of synthetic resin heat-softened by an extruder (not shown) to the outer peripheral surface of the core material 13 between the parison supply portion 14a and the molds 11 and 12. The parison is supplied from the parison supply portion 14a as a so-called bottomless tubular parison with an open bottom. Further, the parison supply device 14 is configured to be able to move up and down by a lifting device (not shown).

-Method of manufacturing sheath connection tube for protecting PC steel-
Next, the case where the sheath connection pipe 1 for protecting PC steel material is molded by the molding apparatus 10 configured as described above will be described.

  First, in a state where the molds 11 and 12 are opened, the ring-shaped seal members 5 are respectively covered at predetermined positions above and below the core material 13 and suctioned and held by the suction blower 16. Thereafter, the parison 1 'is supplied from above to the space between the molds 11, 12 and the core material 13 by the parison supply device 14 to cover the outer periphery of the seal member 5 and to cover the core material 13 together.

  Subsequently, the lower end portion of the parison 1 'is gripped by the chuck device, and in this state, the parison supply device 14 is raised to extend the parison 1' in the axial direction by a predetermined length. In this state, the molds 11 and 12 are clamped. At this time, the slide member 11 c of the mold 11 is disposed at the separated position, and the parison 1 ′ is sandwiched between the molds 11 and 12 excluding the slide member 11 c and the core member 13 via the seal member 5. It will be in the state.

  Thereafter, the slide member 11c is slid from the separated position to the molding position close to the core member 13. Thereby, the cavity formed by the molds 11 and 12 including the slide member 11c and the core member 13 is sealed with the parison 1 '. Hold the member 5 in place. Next, in the suction blower 16, the suction described above is stopped and air is fed into the cavity through the air vent 13b this time, the parison 1 'is cooled and solidified, and the molds 11, 12 are opened after a predetermined time has elapsed. Do.

  The mold opening of the molds 11 and 12 is performed by first sliding the slide member 11 c from the molding position to the separated position, and then opening the molds 11 and 12 to return to the original state, or as necessary After the molds 11 and 12 are opened while the slide member 11c is held at the molding position, the slide member 11c is slid to the separated position so as to return to the original state.

  By opening the molds 11 and 12 in this manner, the sheath connection tube for protecting PC steel material 1 is exposed in a state of being held by the core material 13. Due to its shape, the sheath connecting pipe 1 for protecting PC steel is in a state of being screwed into the core member 13. By rotating the sheath connecting pipe 1 for protecting PC steel by hand by the operator, the PC steel is The protective sheath connection tube 1 can be pulled upward from the core material 13 and released.

  Further, as shown by a two-dot chain line in FIG. 5, a drive unit 17 for rotating the core 13 is provided, and the core 13 is rotated by the drive 17 using the spiral groove 13 a of the core 13. Configure to lower. Therefore, the sheath material connecting pipe 1 for PC steel material protection is released from the core material 13 by rotating the core material 13 by the driving device 17 while holding the PC steel material protective sheath connection pipe 1 fixedly by the take-out device or the like. It can be done.

  As a result, it is possible to form the sheath connecting pipe 1 for protecting the PC steel material, in which the sealing member 5 is welded to the base material of the synthetic resin with an interval L1 from the edge.

  The end portions of the PC steel protection sheath 6 and the PC steel protection sheath 6 can be connected to each other by the sealing member 5 with a high water blocking function by the sheath connection pipe 1 for PC steel protection. .

  As described above, in the present embodiment, since the seal member 5 is integrally formed on the connection side end 4 of the PC steel sheath for protection 1 at a distance L1 from the edge, the PC steel sheath for protection 6 is inserted. When connecting, there is no seal member 5 at the edge and connection is easy. And since the sealing member 5 is integrally shape | molded, the sealing member 5 does not separate easily. Moreover, since it is integrally molded, there is no troublesome operation such as bonding the sealing member 5 later.

  Further, since the seal member 5 can be insert-molded at the time of molding the sheath connection tube 1 for protecting PC steel material, manufacture is easy as compared with the case where the seal member 5 is adhered to a predetermined position after molding. Be done.

  Therefore, according to the sheath connecting tube 1 for protecting PC steel material according to the present embodiment, the inner surface 2 a of the connection side end 4 to which the sheath 6 for protecting PC steel material is connected is liquid at a position spaced from the edge thereof By integrally molding the expandable ring-shaped seal member 5 as described above, the sealability can be improved while securing the ease of screwing in the sheath for protecting PC steel material 6.

(Other embodiments)
The present invention may be configured as follows for the above embodiment.

  That is, a sensor may be provided to detect that grout is filled in the cylindrical portion 3 of the sheath connection tube 1 for protecting PC steel material, or a tube for an air hole may be provided.

  Further, the seal member 5 capable of absorbing the liquid and expanding is not limited to the non-woven fabric, but may be determined according to the purpose of use of the molded product, and the material having the water blocking function is not limited to the non-woven fabric.

  Further, in the above embodiment, the sheath connection tube 1 for protecting PC steel material has the connection side end 4 at both ends and the seal member 5 is provided on both sides, but the connection side end 4 is only at one end. , And one seal member 5 may be provided on the inner surface 2a with a gap L1 from the edge thereof.

  Further, in the present embodiment, the seal member 5 is held on the core member 13 by the suction / blowing device 16, but the seal member 5 is held by the core member 13 alone without using the suction / blowing device 16. It is also good. That is, the suction blower 16 or the vent 13b may be omitted. In this case, the feeding of air to the cavity by the suction blower 16 is also omitted.

  The above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications and uses.

1 Sheath connection tube for protecting PC steel
1 'Parison
2 ridges
2a inside
3 cylindrical part
4 Connection end
5 Seal member
6 PC steel protection sheath
10 Molding equipment
11,12 Mold
11a, 12a inner surface
11b, 12b convex part
11c slide member
13 core material
13a Groove
13b vent
14 parison supply device
14a parison supply department
16 Suction blower
16a hose
17 Drive

Claims (3)

In a sheath connecting pipe for protecting a PC steel material for connecting a PC steel protection sheath molded into a helical uneven shape into which PC steel is inserted and grout is injected,
At least one side has an inner circumferential surface engageable with the concavo-convex shape of the outer circumferential surface of the sheath for protecting the PC steel material, and an inner circumferential side of the connection side end to which the sheath for protecting the PC steel steel is connected A sheath connecting pipe for protecting PC steel material, wherein a ring-shaped seal member capable of absorbing liquid and expanding is integrally formed at a position spaced apart from the part. In the sheath connecting pipe for protecting PC steel material according to claim 1,
The sealing member is a non-woven fabric, and the non-woven fabric is welded and integrated to form a sheath connecting pipe for protecting PC steel material. In a method of manufacturing a sheath connecting pipe for protecting a PC steel material for protection of a resin, wherein a PC steel material is inserted into the inside and a grout is injected and which connects a PC steel protection sheath molded into a helical uneven shape,
The PC steel material is protected by insert molding a ring-shaped seal member capable of absorbing liquid and expanding at a position spaced from the edge on the inner surface side of the connection side end to which the PC steel material protective sheath is connected What is claimed is: 1. A method for manufacturing a sheath connecting pipe for protecting PC steel material, comprising: forming an inner peripheral surface engageable with an outer peripheral surface of a sheath for sheathing.

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