Method for manufacturing precast concrete member and cap member used for the same

Abstract

To shorten a manufacturing time and reduce a cost by easily manufacturing a precast concrete member in which a joint member is embedded.SOLUTION: A precast concrete member 1 is manufactured in which a joint member 10 is embedded by using a cap member 28 which includes a cap attachment male screw 22 formed with an outer diameter engaged with a screw-knotted reinforcement coupling female screw 16, a cap 24 provided at the end of the cap attachment male screw 22 in an axial direction, a male screw member coupling female screw 26 provided penetrating the cap 24 from the cap 24 to the cap attachment male screw 22 and formed with an inner diameter of a prescribed value irrespective of the size of the outer diameter of the cap attachment male screw 22, and a rotation operation locking member 28 for rotating the cap 24 formed on an outer end surface 2402 of the cap 24 positioned opposite to the cap attachment male screw 22.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a precast concrete member and a cap member used in the manufacturing method.

Background Art

[0002] When constructing a concrete structure, concrete jointing may be performed by driving new concrete into a precast concrete member. For concrete jointing, a joint member such as a threaded bar is screwed into one end in the axial direction of an elongated cylindrical portion having an internal thread formed on the inner peripheral portion is used.

[0003] For example, in Patent Document 1, a reinforcing bar is connected to a joint member (relay joint) embedded in a precast concrete member, and concrete is placed and cured in a concrete accommodating portion surrounded by precast concrete members on four sides to form a footing in which the placed concrete portion and the precast concrete member are integrated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to manufacture a precast concrete member in which a joint member is embedded as described above, conventionally, an insertion hole was drilled in a steel plate constituting a concrete formwork, and the opening of the female screw of the joint member was applied coaxially with this insertion hole to the inner surface of the steel plate. A male screw member was inserted into the insertion hole of the steel plate from the outer surface of the steel plate and screwed into the female screw of the joint member to attach the joint member to the steel plate. Then, concrete is placed in the concrete formwork and cured, and thereafter, the concrete formwork is removed to take out the precast concrete member.

[0006] By the way, the outer diameter of the threaded deformed bar protruding from the precast concrete member is selected to match the cross-sectional area, length, etc. of the concrete member that is newly cast with concrete and integrated with the precast concrete member through the threaded deformed bar. Therefore, conventionally, every time a precast concrete member is manufactured, a joint member having a female screw that can be screwed onto the threaded deformed bar to be used is created. Also, a male screw member having an outer diameter that screws into the female screw of the joint member is prepared. And an insertion hole was formed in the steel plate constituting the concrete formwork so that this male screw member could be inserted therethrough. That is, the manufacture of the precast concrete member was complicated and time-consuming, and the cost was increasing.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a precast concrete member that can easily manufacture a precast concrete member in which a joint member is embedded, shorten the manufacturing time, and reduce the cost, and a cap member used in the manufacturing method.

Means for Solving the Problems

[0008] In order to achieve the above object, an embodiment of the present invention is a method for manufacturing a precast concrete member in which a joint member for projecting a threaded deformed bar is embedded, the method comprising: a slender cylindrical portion having a female thread for coupling a threaded deformed bar formed on an inner peripheral portion thereof, the female thread being threadable with the threaded deformed bar; the joint member having a female thread opening of the female thread for coupling the threaded deformed bar formed at one end in the axial direction of the cylindrical portion; a male thread portion for attaching a cap formed with an outer diameter that is screwed into the female thread for coupling the threaded deformed bar; a lid portion provided at an axial end of the male thread portion for attaching the cap, the lid portion closing the female thread opening in a state where the male thread portion for attaching the cap is screwed into the female thread for coupling the threaded deformed bar; a female thread for coupling a male thread member formed with an inner diameter of a predetermined value regardless of the outer diameter of the male thread portion for attaching the cap, the female thread being provided so as to penetrate the lid portion and extend from the lid portion to the male thread portion for attaching the cap; and a locking portion for rotational operation formed on an outer end surface of the lid portion located opposite to the male thread portion for attaching the cap, the locking portion being for rotating the lid portion. A male thread member having a male thread provided so as to be screwable with the female thread for coupling the male thread member is prepared. The male thread portion for attaching the cap of the cap member is coupled to the female thread for coupling the threaded deformed bar of the joint member to provide a joint-cap assembly in which the female thread opening is closed by the lid portion. A male thread member insertion hole allowing insertion of the male thread member is provided in a plate member constituting the concrete formwork. The male thread member is inserted into the male thread member insertion hole, and the outer end surface of the lid portion is brought into contact with the inner surface of the plate member constituting the inner surface of the concrete formwork and around the male thread member insertion hole coaxially therewith. The male thread member is screwed and coupled to the female thread for coupling the male thread member, thereby attaching the joint-cap assembly to the inner surface of the plate member. Concrete is placed inside the concrete formwork to manufacture the precast concrete member inside the concrete formwork. After manufacturing, the male thread member is removed from the female thread for coupling the male thread member, and the precast concrete member is taken out of the concrete formwork. The cap member is removed from the joint-cap assembly by locking a tool to the locking portion for rotational operation and rotating it. Further, in one embodiment of the present invention, the rotation operation locking portion is formed in a predetermined shape regardless of the outer diameter of the male screw portion for cap attachment. Further, in one embodiment of the present invention, in a state where the male screw portion for cap attachment of the cap member is coupled to the female screw for joining screw-reinforced bars of the joint member, when viewed from the axial direction of the female screw for joining screw-reinforced bars, the lid portion is formed with a larger contour than the cylindrical portion. Further, in one embodiment of the present invention, it includes a male screw portion for cap attachment formed with an outer diameter that screws into the female screw for joining screw-reinforced bars, a lid portion provided at an axial end of the male screw portion for cap attachment with an outer diameter larger than the outer diameter of the male screw portion for cap attachment, a female screw formed with an inner diameter of a predetermined value that penetrates the lid portion and extends from the lid portion to the male screw portion for cap attachment regardless of the outer diameter of the male screw portion for cap attachment, and a rotation operation locking portion formed on the outer end surface of the lid portion located opposite to the male screw portion for cap attachment for rotating the lid portion. Further, in one embodiment of the present invention, the rotation operation locking portion is formed in a predetermined shape regardless of the outer diameter of the male screw portion for cap attachment.

Advantages of the Invention

[0009] According to one embodiment of the present invention, a cap member that screws into the female screw for joining screw-reinforced bars of the joint member is provided, and the cap member is provided with a female screw for joining male screw members formed with an inner diameter of a predetermined value regardless of the size of the female screw for joining screw-reinforced bars of the joint member. Therefore, as a male screw member for fixing the joint member to the formwork plate material, a male screw member having a predetermined outer diameter can be used regardless of the size of the outer diameter of the threaded deformed bar protruding from the precast concrete member through the joint member. Further, the inner diameter of the male screw member insertion hole provided in the formwork plate material can be formed to have a predetermined inner diameter regardless of the size of the outer diameter of the threaded deformed bar protruding from the precast concrete member through the joint member. Therefore, it is not necessary to prepare male screw members with different outer diameters each time according to the size of the outer diameter of the threaded deformed bar protruding from the precast concrete member through the joint member, and it is not necessary to re-drill male screw member insertion holes with different inner diameters in the formwork plate material each time. As a result, a precast concrete member in which the joint member is embedded can be easily manufactured, and a manufacturing method of a precast concrete member advantageous in shortening the manufacturing time and reducing the cost can be obtained.

[0010] Further, if the rotation operation locking portion is formed in a predetermined shape regardless of the size of the outer diameter of the male screw portion for cap attachment, it is not necessary to prepare a tool each time according to the size of the outer diameter of the threaded deformed bar protruding from the precast concrete member through the joint member. Therefore, the cap member can be attached to and detached from the joint member with a single tool, which is advantageous in improving the working efficiency in the manufacture of precast concrete members.

[0011] Further, when viewed from the axial direction of the female screw for joining the threaded deformed bars, if the lid portion is formed with a larger contour than the cylindrical portion, a precast concrete member in which the concrete portion filled outside the lid portion is easily broken or an incomplete precast concrete member having a gap outside the lid portion is not manufactured, which is advantageous in manufacturing a precast concrete member with a good appearance. It is also advantageous for stably attaching the joint-cap combined body to the inner surface of the concrete formwork.

[0012] In addition, a cap member that is screwed into the female screw for connecting the threaded bar is provided, and the cap member is provided with a female screw formed with an inner diameter of a predetermined value regardless of the size of the inner diameter of the female screw for connecting the threaded bar. Therefore, for example, when attaching a joint member having a female screw for connecting the threaded bar to the plate material of the concrete formwork, a male screw member with an outer diameter of a predetermined value can be used regardless of the size of the inner diameter of the female screw for connecting the threaded bar. Further, the inner diameter of the hole for inserting the male screw member provided in the plate material of the concrete formwork can be formed with an inner diameter of a predetermined value regardless of the size of the inner diameter of the female screw for connecting the threaded bar. Accordingly, it is not necessary to prepare male screw members with different outer diameters each time corresponding to the size of the outer diameter of the threaded bar protruding from the precast concrete member through the joint member. Also, it is not necessary to re-drill holes for inserting male screw members with different inner diameters in the formwork plate material each time. As a result, the precast concrete member with the joint member embedded can be easily manufactured, which is advantageous in shortening the manufacturing time and reducing costs.

[0013] In addition, if the locking portion for rotational operation is formed in a predetermined shape regardless of the size of the outer diameter of the male screw portion for cap attachment, it is not necessary to prepare tools each time corresponding to the size of the outer diameter of the threaded bar protruding from the precast concrete member through the joint member. For this reason, the cap member can be attached to and detached from the joint member with a single tool, which is advantageous in improving the working efficiency in the manufacture of precast concrete members.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 15 is a sectional view of a portion where a joint member 10 of a precast concrete member 1 manufactured by the manufacturing method of the present invention is embedded. As shown in FIG. 1, the precast concrete member 1 of the present embodiment has a threaded deformed bar T coupled to the embedded joint member 10 at a building construction site and is used as a beam member. Therefore, the joint member 10 shown in FIG. 2 is embedded in the precast concrete member 1 in order to project the threaded deformed bar T.

[0016] In the present embodiment, the joint member 10 and the cap member 20 shown in FIGS. 3 and 4 are combined to assemble a joint-cap assembly 40 shown in FIG. 6(B). Then, this joint-cap assembly 40 is attached to a concrete form 30 using a male screw member 42 that is screwed into a female screw 26 for coupling the male screw member of the cap member 20 as shown in FIG. 8(A), and the precast concrete member 1 is manufactured using the concrete form 30.

[0017] First, referring to FIG. 2, the joint member 10 will be described in detail. The joint member 10 is made of metal and is configured to include a cylindrical portion 12 as shown in FIG. 2. The joint member 10 is a member for coupling a threaded deformed bar T that projects from the precast concrete member 1. The cylindrical portion 12 has an elongated shape with a regular hexagonal cross section, and a female screw 16 for coupling a threaded deformed bar, into which the threaded deformed bar can be screwed, is formed on the inner peripheral portion. At one end 1202 in the axial direction of the cylindrical portion 12, a female screw opening 1602 of the female screw for threaded rib reinforcement connection is formed. As shown in FIG. 1, the joint member 10 is embedded in the precast concrete member 1 so that the female screw opening 1602 is exposed.

[0018] At the other end 1204 in the axial direction of the cylindrical portion 12, which is located opposite to the female screw opening 1602, a reinforcing bar 14 projects integrally with the cylindrical portion 12. The reinforcing bar 14 is a threaded rib bar, which projects by being screwed into the female screw for threaded rib reinforcement connection 16 from the other end 1204 side of the cylindrical portion 12. In this embodiment, the reinforcing bar 14 is fixed to a predetermined position of the cylindrical portion 12 by welding 18.

[0019] Note that the joint member 10 is not limited to the above-described one, and various conventionally known ones to which the threaded rib bar T projecting from the precast concrete member 1 can be coupled are applicable. For example, the joint member 10 may be composed only of the cylindrical portion 12, or a rod or the like may be fixed to the cylindrical portion 12 instead of the reinforcing bar 14.

[0020] Next, the cap member 20 will be described with reference to FIGS. 3, 4, and 6. The cap member 20 is made of metal and is a member that couples to the female screw for threaded rib reinforcement connection 16 of the joint member 10 and closes the female screw opening 1602, as shown in FIG. 6. As shown in FIGS. 3 and 4, the cap member 20 includes a male screw portion 22 for cap attachment and a lid portion 24. The male screw portion 22 for cap attachment is cylindrical, and an external male screw 2202 having an outer diameter that screws into the female screw for threaded rib reinforcement connection 16 is formed on the outer peripheral portion.

[0021] The lid portion 24 is an annular plate-shaped member provided at the axial end of the male screw portion 22 for cap attachment, and closes the female screw opening 1602 in a state where the male screw portion 22 for cap attachment is screwed into the female screw for threaded rib reinforcement connection 16 of the joint member 10, as shown in FIG. 6(B). As shown in Fig. 4, the outer diameter of the lid portion 24 is formed to be larger than the outer diameter of the male screw portion 22 for cap attachment. Also, as shown in Fig. 6(B), the lid portion 24 is formed with a contour larger than the contour of the cylindrical portion 12 when viewed from the axial direction of the female screw 16 for joining the screw joint reinforcing bars, with the male screw portion 22 for cap attachment of the cap member 20 joined to the female screw 16 for joining the screw joint reinforcing bars of the joint member 10. In the present embodiment, since the contour of the cylindrical portion 12 is a regular hexagon, the lid portion 24 is formed in a circular shape with a contour larger than that hexagon.

[0022] The cap member 20 is provided so as to penetrate the center of the lid portion 24 and extend from the lid portion 24 to the male screw portion 22 for cap attachment, and a female screw 26 for joining male screw members is formed with an inner diameter of a predetermined value regardless of the size of the outer diameter of the male screw portion 22 for cap attachment. The female screw 26 for joining male screw members allows a predetermined male screw member 42 (Fig. 11) to be screwed in. For example, in the female screw 26 for joining male screw members of the present embodiment, a male screw member 42 of M6 (JIS standard) can be screwed in.

[0023] As shown in Figs. 3(A) and 4(B), on the outer end surface 2402 of the lid portion 24 located opposite to the male screw portion 22 for cap attachment, a locking portion 28 for rotational operation for rotating the lid portion 24 is formed. The outer end surface 2402 is formed as a flat surface. The locking portion 28 for rotational operation is formed by a pair of groove portions formed in a rectangular shape facing each other and extending radially outward from the female screw 26 for joining male screw members on the diameter of the female screw 26 for joining male screw members of the lid portion 24.

[0024] In addition, as shown in Fig. 1, when the screw joint reinforcing bar T is projected from the precast concrete member 1, the joint member 10 is provided with a female screw 16 for joining the screw joint reinforcing bar T to be used. Further, the cap member 20 is provided with a male screw portion 22 for cap attachment that joins to the female screw 16 for joining the screw joint reinforcing bars of the joint member 10. On the other hand, the inner diameter of the female screw 26 for male screw member connection provided on the cap member 20, the outer diameter of the male screw member 42, and the locking portion 28 for rotational operation provided on the outer end surface 2402 of the lid portion 24 always have dimensions of a predetermined value regardless of the outer diameter of the screw joint reinforcing bar T to be used.

[0025] Next, with reference to FIG. 5, the concrete formwork 30 for forming the precast concrete member 1 will be described. The concrete formwork 30 is configured as a rectangular parallelepiped with an open top surface, and has a U-shaped cross section. In the present embodiment, on the steel plate 32 constituting the side surface of the concrete formwork 30, a male screw member insertion hole 34 through which a male screw member 42 having a male screw that can be screwed into the female screw 26 for male screw member connection of the cap member 20 can be inserted is provided. Note that since the outer diameter of the male screw member 42 is always formed with dimensions of a predetermined value regardless of the outer diameter of the screw joint reinforcing bar T to be used, the inner diameter of the male screw member insertion hole 34 is also formed with dimensions of a predetermined value. The concrete formwork 30 of the present embodiment is made of a steel plate, but may be made of a plate material using other materials such as wood as long as concrete can be placed and a male screw member insertion hole can be provided. Also, the number and position of the male screw member insertion holes are arbitrary and are determined according to the precast concrete member 1 to be manufactured.

[0026] Next, with reference to FIGS. 6 to 16, the manufacturing procedure for manufacturing the precast concrete member 1 in which the joint member 10 of the present embodiment is embedded will be described. First, as shown in FIGS. 6(A) and (B), a joint-cap assembly 40 is assembled from the joint member 10 and the cap member 20. That is, as shown in FIG. 6(A), from a state where one end 1202 of the cylindrical portion 12 of the joint member 10 and the male screw portion 22 for cap attachment of the cap member 20 are opposed to each other, while screwing the male screw portion 22 for cap attachment of the cap member 20 into the female screw 16 for screw joint reinforcing bar connection of the joint member 10, it is inserted. Then, as shown in FIG. 6(B), a joint-cap assembly 40 is provided by coupling the male screw portion 22 for cap attachment of the cap member 20 to the female screw 16 for coupling the threaded ribbed steel bar of the joint member 10, and closing the female screw opening 1602 with the lid portion 24. Note that by closing the female screw opening 1602 with the lid portion 24, it is possible to prevent concrete from flowing into the female screw 16 for coupling the threaded ribbed steel bar of the joint member 10 during the placement of concrete.

[0027] Next, as shown in FIG. 7(A), a male screw member insertion hole 34 that enables the insertion of the male screw member 42 is formed at a predetermined position of the steel plate 32 that constitutes the side surface of the concrete form 30. Then, as shown in FIG. 7(B), the outer end surface 2402 of the lid portion 24 is brought into contact with the inner surface 3202 of the steel plate 32 that constitutes the inner surface of the concrete form 30, coaxially with the male screw member insertion hole 34 and around the male screw member insertion hole 34.

[0028] Next, as shown in FIGS. 8(A) and 11, the male screw member 42 (M6 bolt) inserted through the male screw member insertion hole 34 from the outer surface side of the concrete form 30 is screwed and coupled to the female screw 26 for coupling the male screw member, thereby sandwiching the steel plate 32 between the lid portion 24 of the cap member 20 and the head of the male screw member 42, and attaching the joint-cap assembly 40 to the inner surface 3202 of the steel plate 32. When the joint-cap assembly 40 is attached to the concrete form 30, as shown in FIGS. 8(B) and 12, concrete C is placed inside the concrete form 30 to manufacture the precast concrete member 1 inside the concrete form 30.

[0029] When the concrete C has hardened after a predetermined time has elapsed and the precast concrete member 1 has been manufactured, as shown in FIGS. 9(A) and 13, the male screw member 42 is removed from the female screw 26 for coupling the male screw member. Then, as shown in FIGS. 9(B) and 14, the concrete form 30 is removed to take out the precast concrete member 1 from the concrete form 30. Furthermore, as shown in FIGS. 10(A) and 15, the cap member 20 is removed from the female screw 16 for screw-coupling the joint-cap coupling body 40 embedded in the precast concrete member 1. The cap member 20 can be easily removed from the joint-cap coupling body 40 by locking a tool such as a minus driver to the rotation operation locking portion 28 (see FIG. 14) and rotating it. Thereby, the precast concrete member 1 in which the joint member 10 is embedded is manufactured.

[0030] Thereafter, when the precast concrete member 1 shown in FIGS. 10(A) and 15 is transported to the construction site and the concrete jointing work is performed, as shown in FIGS. 10(B) and 16, the threaded bar T is screwed and inserted from the female screw opening 1602 of the joint member 10 embedded in the precast concrete member 1, and the threaded bar T is coupled to the joint member 10. Thereby, the precast concrete member 1 with the threaded bar T protruding as shown in FIG. 1 is obtained.

[0031] Thus, according to the present embodiment, the cap member 20 that screws into the female screw 16 for screw-coupling the joint member 10 is provided, and the cap member 20 is provided with the female screw 26 for male screw member coupling formed with an inner diameter of a predetermined value regardless of the size of the female screw 16 for screw-coupling the joint member 10. Therefore, as the male screw member 42 for fixing the joint member 10 to the steel plate 32 of the concrete form 30, one having an outer diameter of a predetermined value can be used regardless of the size of the outer diameter of the threaded bar T protruding from the precast concrete member 1 through the joint member 10. Further, the inner diameter of the male screw member insertion hole 34 provided in the steel plate 32 of the concrete form 30 can be formed with an inner diameter of a predetermined value regardless of the size of the outer diameter of the threaded bar T protruding from the precast concrete member through the joint member 10. Therefore, it is no longer necessary to prepare male screw members 42 with different outer diameters each time according to the size of the outer diameter of the threaded bar T protruding from the precast concrete member 30 through the joint member 10. Also, it is no longer necessary to re-drill the male screw member insertion holes 34 with different inner diameters in the steel plate 32 of the concrete formwork 30 each time. As a result, a precast concrete member 1 with the joint member 10 embedded therein can be easily manufactured, and a manufacturing method of the precast concrete member 1 that is advantageous in shortening the manufacturing time and reducing costs can be obtained.

[0032] That is, the outer diameter of the threaded bar T protruding from the precast concrete member 1 is not a uniform value because dimensions are selected according to the cross-sectional area, length, etc. of the concrete member that newly pours concrete and integrates with the precast concrete member 1. In the present embodiment, when the outer diameters of the threaded bars T are different, a joint member 10 is manufactured in which the inner diameter of the female screw 16 for connecting the threaded bars is formed accordingly. Also, a cap member 20 that couples to this joint member 10 is manufactured. When manufacturing this cap member 20, the inner diameter of the female screw 26 for connecting the male screw member provided in the cap member 20 and the outer diameter of the male screw member 42 are always formed as constant values regardless of the outer diameter of the threaded bar T. That is, even when using a joint member 10 with different inner diameters of the female screw 16 for connecting the threaded bars, the joint member 10 can be attached to the inner surface 3202 of the concrete formwork 30 provided with the male screw member insertion hole 34 through which a predetermined male screw member 42 can be inserted via the cap member 20 by the predetermined male screw member 42. For this reason, the male screw member insertion hole 34 and the male screw member 42 can be made common, which is advantageous in easily manufacturing the precast concrete member 1 with the joint member 10 embedded therein, shortening the manufacturing time, and reducing costs.

[0033] In addition, the locking portion 28 for rotation operation is formed in a predetermined shape regardless of the outer diameter of the male screw portion 22 for cap attachment. Therefore, it is not necessary to prepare a tool each time according to the outer diameter of the threaded bar T protruding from the precast concrete member 1 via the joint member 10. Therefore, the cap member 20 can be attached to and detached from the joint member 10 with a single tool, which is advantageous in improving the working efficiency in manufacturing the precast concrete member 1.

[0034] In addition, in a state where the male screw portion 22 for cap attachment of the cap member 20 is coupled to the female screw 16 for coupling the threaded bar of the joint member 10, when viewed from the axial direction of the female screw 16 for coupling the threaded bar, the lid portion 24 is formed with a larger contour than the cylindrical portion 12. Therefore, it is advantageous in manufacturing a precast concrete member 1 with a good appearance without manufacturing a precast concrete member 1 in which the concrete portion filled outside the lid portion 24 is easily broken or an incomplete precast concrete member 1 in which a gap is generated outside the lid portion 24. In addition, it is advantageous for stably attaching the joint-cap coupling body 40 to the inner surface 3202 of the concrete form 30.

[0035] The cap member 20 includes a male screw portion 22 for cap attachment formed with an outer diameter that screws into the female screw 16 for coupling the threaded bar, and a lid portion 24 provided with an outer diameter larger than the outer diameter of the male screw portion 22 at an axial end of the male screw portion 22 for cap attachment. And a female screw 26 for coupling the male screw member is provided, which penetrates the lid portion 24 and extends from the lid portion 24 to the male screw portion 22 for cap attachment, and is formed with an inner diameter of a predetermined value regardless of the outer diameter of the male screw portion 22 for cap attachment. Further, a locking portion 28 for rotation operation for rotating the lid portion 24 is provided on the outer end surface 2402 of the lid portion 24 located opposite to the male screw portion 22 for cap attachment. Therefore, for example, when attaching the joint member 10 having the female thread 16 for threaded bar reinforcement to the steel plate 32 of the concrete formwork 30, a male thread member 42 with an outer diameter of a predetermined value can be used regardless of the inner diameter of the female thread 16 for threaded bar reinforcement. Further, the inner diameter of the male thread member insertion hole 34 provided in the steel plate 32 of the concrete formwork 30 can be formed with a predetermined inner diameter regardless of the inner diameter of the female thread 16 for threaded bar reinforcement. Therefore, it is not necessary to prepare male thread members 42 with different outer diameters each time according to the outer diameter of the threaded bar T protruding from the precast concrete member 1 via the joint member 10, and it is not necessary to re-drill male thread member insertion holes 34 with different inner diameters in the steel plate 32 of the concrete formwork 30 each time. This makes it possible to easily manufacture the precast concrete member 1 in which the joint member 10 is embedded, which is advantageous in shortening the manufacturing time and reducing costs.

[0036] That is, the cap member 20 is provided with a female thread 26 for male thread member connection to which a predetermined male thread member 42 is screwed. Therefore, the joint member 10 can be attached to the inner surface 3202 of the concrete formwork 30 provided with the male thread member insertion hole 34 through which the predetermined male thread member 42 can be inserted via the cap member 20 by the predetermined male thread member 42. For this reason, the male thread member insertion hole 34 and the male thread member 42 can be made common, which is advantageous in easily manufacturing the precast concrete member 1 in which the joint member 10 is embedded, shortening the manufacturing time, and reducing costs. In addition, the cap member 20 can be easily removed by locking a tool such as a minus driver to the rotation operation locking portion 28 and performing a rotation operation.

Explanation of Reference Numerals

[0037] 1 Precast concrete member 10 Joint member 12 Cylindrical portion 14 Reinforcing bar 16 Female thread for connecting threaded bars 1602 Male thread opening 18 Welding 20 Cap member 22 Male thread portion for attaching the cap 24 Cover part 2402 Outer end face 28 Locking part for rotational operation 30 Concrete formwork 32 Steel plate 34 Insertion hole for male thread member 40 Joint - cap combination 42 Male thread member C Concrete T Threaded bar

Claims

1. A method for manufacturing a precast concrete member in which a joint member for projecting a threaded bar is embedded, comprising: a joint member having an elongated cylindrical portion formed with a female thread for coupling a threaded bar, which can be screwed into the threaded bar, at an inner peripheral portion thereof, and a female thread opening of the female thread for coupling the threaded bar formed at one end in the axial direction of the cylindrical portion; a male thread portion for attaching a cap formed with an outer diameter that is screwed into the female thread for coupling the threaded bar; a lid portion provided at an axial end of the male thread portion for attaching the cap, which closes the female thread opening in a state where the male thread portion for attaching the cap is screwed into the female thread for coupling the threaded bar; a female thread for coupling a male thread member formed with an inner diameter of a predetermined value regardless of the outer diameter of the male thread portion for attaching the cap, provided through the lid portion and extending from the lid portion to the male thread portion for attaching the cap; and a locking portion for rotational operation formed on an outer end surface of the lid portion located opposite to the male thread portion for attaching the cap for rotating the lid portion; preparing a male thread member having a male thread provided so as to be screwable into the female thread for coupling the male thread member; providing a joint-cap assembly in which the male thread portion for attaching the cap of the cap member is coupled to the female thread for coupling the threaded bar of the joint member, and the female thread opening is closed by the lid portion; providing a male thread member insertion hole enabling insertion of the male thread member in a plate member constituting a concrete form; on the inner surface of the plate member constituting the inner surface of the concrete form, with the outer end surface of the lid portion in contact with the periphery of the male thread member insertion hole coaxially with the male thread member insertion hole, screwing and coupling the male thread member inserted through the male thread member insertion hole to the female thread for coupling the male thread member to attach the joint-cap assembly to the inner surface of the plate member; placing concrete inside the concrete form to manufacture the precast concrete member inside the concrete form, and after manufacturing, removing the male thread member from the female thread for coupling the male thread member and removing the precast concrete member from the concrete form; removing the cap member from the joint-cap assembly by locking and rotating a tool to the locking portion for rotational operation; A method for manufacturing a precast concrete member, characterized by the above.

2. The rotation operation engaging portion is formed in a predetermined shape regardless of the outer diameter of the male screw portion for cap attachment. The method for manufacturing a precast concrete member according to claim 1, characterized in that.

3. In a state where the male screw portion for cap attachment of the cap member is coupled to the female screw for coupling screw-bar reinforcement of the joint member, when viewed from the axial direction of the female screw for coupling screw-bar reinforcement, the lid portion is formed with a larger contour than the cylindrical portion. The method for manufacturing a precast concrete member according to claim 1, characterized in that.

4. A male screw portion for cap attachment formed with an outer diameter that screws into the female screw for coupling screw-bar reinforcement, A lid portion provided at an axial end of the male screw portion for cap attachment with an outer diameter larger than the outer diameter of the male screw portion for cap attachment, A female screw provided through the lid portion and extending from the lid portion to the male screw portion for cap attachment, formed with an inner diameter of a predetermined value regardless of the outer diameter of the male screw portion for cap attachment, A rotation operation engaging portion formed on the outer end surface of the lid portion located opposite to the male screw portion for cap attachment for rotating the lid portion, A cap member, characterized by comprising.

5. The rotation operation engaging portion is formed in a predetermined shape regardless of the outer diameter of the male screw portion for cap attachment. The cap member according to claim 4, characterized in that.

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