Structure for retaining embedded members in formwork for manufacturing precast concrete products and method for attaching embedded members

Abstract

To enable the easy fitting of an insert to a flask, the secure holding of the insert till the demolding of a concrete product and the easy removal of a holding tool upon demolding.SOLUTION: An insert holding structure comprises: an insert fitting hole 51 provided at a flask 50; an insert holding tool 20 having an outer peripheral shape gradually diameter-reduced from the inner side of the flask 50 toward the outer side thereof; an insert fixing tool 30 fitted to the insert fitting hole 51, having an inner peripheral shape coincident with the outer peripheral shape of the insert holding tool 20 and fixing the insert holding tool 20 to the flask 50 in a state of being stuck therein so as to be fixed; a connection tool 40 connecting the insert holding tool 20 and the insert fixing tool 30 and having a brittle part 42 broken when external force greater than a specified level is applied; and a connection part provided between an insert 10 and the insert holding tool 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an embedded member holder and an embedded member installation method in formwork for manufacturing precast concrete products, and more particularly to a holder used to embed an embedded member such as an insert (hereinafter, the insert will be referred to as a representative example of an embedded member) inside a shield segment, and a method for installing an embedded member inside a shield segment. [Background technology]

[0002] In general forms for manufacturing precast concrete products, embedded members are bolted from the back side of the form. However, in cases where it is difficult to operate the form from the back side (where it is difficult to bolt the embedded members), such as in the case of shield segments, plastic bolts are used to fix the embedded members from the inside of the form, and by breaking the plastic bolts when the shield segments are removed, it is possible to install the embedded members inside the shield segments without removing the plastic bolts. These plastic bolts are generally provided with weak parts to make them easier to break.

[0003] Thus, various techniques for fixing embedding members to a formwork when manufacturing a precast concrete product have been disclosed (see Patent Documents 1 to 3). The technique described in Patent Document 1 fixes the embedding member to the formwork by attaching a fixture made of an elastic body such as rubber or soft resin to a hole provided in the formwork and pushing the fixture into the cylindrical part (female thread part) of the embedding member nut. Then, when the formwork is opened, the fixture comes off the embedding member nut and the product can be removed from the formwork.

[0004] In the technology described in Patent Document 2, a mounting fixture consisting of a nylon resin boss and bolt is inserted into a bolt hole provided in the formwork, and then fastened and fixed with a nut from the back side of the formwork, and attached to the formwork with the boss protruding from the inner surface of the formwork. To attach an embedding member to the formwork, the embedding member is held by hand and pressed into the boss protruding from the inner surface of the formwork. In this technology, the embedding member is held by two members, the boss and the base, so that it is resistant to vibrations from a vibrator and the embedding member will not fall out, and when the formwork is opened, it can be easily removed from the formwork without removing the mounting fixture from the formwork.

[0005] In the technology described in Patent Document 3, an embedding member for embedding in a concrete product has an embedding portion that is embedded in the concrete product and an exposed portion that is exposed from the concrete product. The exposed portion is provided with a horizontal hole for passing a connecting member such as a bolt that connects it to another member. Then, when the embedding member is set in the formwork and the shaft is rotated to move the part of the cam with a large eccentric distance, the L-shaped lever rotates due to the elasticity of the spring connecting the two, and with the locking portion engaged with the horizontal hole of the exposed portion, the elastic pressure of the spring is applied, and the embedding member is fixed to the inner surface of the formwork. When the locking portion is released from the engagement with the horizontal hole of the exposed portion, the embedding member is released from the fixation between the formwork and the embedding member.

[0006] Also, a technology has been disclosed in which a weak part is provided in a member embedded inside a concrete product, and the embedded member is removed by breaking the weak part when the product is removed (see Patent Document 4). This technology relates to a form holder for maintaining a constant gap inside a concrete form when the form is assembled. The auxiliary cone used in the form holder has a truncated cone shape integrally molded from synthetic resin, and is composed of a semi-frustum conical shell-shaped member divided into two on its axis. To attach the auxiliary cone to the form holder, the two divided members are opened and wrapped around the form receiving piece to form an integrated unit.

[0007] This allows the form support piece to fit into the opening, and the tip of the annular protrusion is loosely fitted in the break-off groove. When the form is dismantled after the concrete has hardened, the form support piece and the auxiliary cone remain in the concrete, and the separator's end, including its threaded portion, protrudes from the surface of the concrete. When a bending pipe is inserted into the threaded portion and twisted, the protruding end of the separator breaks at the bending groove, allowing it to be removed together with the form support piece. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 6-81482 [Patent Document 2] Japanese Patent Application Publication No. 7-216996 [Patent Document 3] Japanese Patent Application Publication No. 7-233631 [Patent Document 4] Japanese Utility Model Application Publication No. 5-83198 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when concrete is poured into a formwork containing embedded members fixed to the formwork using plastic screws, the embedded members may fall over due to a vibrator coming into contact with the embedded members, causing the plastic bolts to break. If this happens, the concrete product will not have the embedded members embedded in the designated positions, resulting in a defective product that cannot be shipped.

[0010] In addition, if steel bolts are used as holders for embedded members such as inserts, the embedded members will not fall over. However, plastic bolts have the advantage that they break when demolded, making it unnecessary to remove the bolts. On the other hand, when steel bolts are used, the extra work of removing the bolts when demolding is required, which is problematic in terms of work efficiency.

[0011] In particular, with large embedded components, the force acting on the plastic bolt to topple the embedded component is large, increasing the risk of the embedded component falling over. For example, if the embedded component is reinforcing bar-shaped and has a large diameter, the overall length of the embedded component will also be long, further increasing the risk of the embedded component falling over.

[0012] In addition, if a sufficient working area cannot be secured below the formwork, the work of attaching the holders becomes difficult, for example, by having to crawl under the formwork to perform the work. As a holder, It is preferable to use plastic bolts that can be broken when the concrete is removed from the form, and to have a structure that can securely hold the embedded members even if they come into contact with a vibrator or other device used to compact the poured concrete.

[0013] The prior art, including the techniques described in the above-mentioned patent documents, does not disclose any embedding member holder having such a structure or a method for holding an embedding member.

[0014] The present invention has been proposed in consideration of the above-mentioned circumstances, and aims to provide an embedded member holding structure and an embedded member installation method in a formwork for manufacturing precast concrete products, which allows the embedded member to be easily attached to the formwork, can securely hold the embedded member until the concrete product is demolded, and can easily remove the retaining device when the concrete product is demolded. [Means for solving the problem]

[0015] The embedded member retaining structure and embedded member mounting method in a formwork for manufacturing precast concrete products according to the present invention (hereinafter sometimes abbreviated as the embedded member retaining structure (insert retaining structure) and the embedded member mounting method (insert mounting method)) have the following features in order to achieve the above-mentioned objectives. Note that the embedded member refers to, for example, an insert, but other embedded members include grout injection ports and the like.

[0016] The embedding member holding structure according to the present invention is a holding structure for holding an embedding member in a formwork for manufacturing a precast concrete product, and includes an embedding member mounting hole provided at an embedding member mounting position of the formwork, an embedding member holder having an outer peripheral shape that gradually decreases in diameter from the inside to the outside of the formwork, and an embedding member mounting hole. To The embedding member fixing device is attached to the formwork and has an inner peripheral shape that matches the outer peripheral shape of the embedding member holder, and is attached and fixed to the formwork with the embedding member holder fitted inside; a connecting device that connects the embedding member holder and the embedding member fixing device and has a fragile part that breaks when an external force equal to or greater than a predetermined value is applied; and a connecting part that is provided between the embedding member and the embedding member holder and connects the two.

[0017] The inside of the formwork refers to the side where concrete is poured, and the outside of the formwork refers to the outside of the formwork that is not the side where concrete is poured. The embedment member holder has an outer periphery that gradually narrows in diameter from the inside of the formwork to the outside of the formwork, so that the inside of the formwork is the expanded diameter part and the outside of the formwork is the reduced diameter part.

[0018] In the embedment member holding structure described above, the inner peripheral surface of the embedment member fixing tool and the outer peripheral surface of the embedment member holder may be configured to be cone-shaped and in contact with each other.

[0019] In addition, the embedded member has a female threaded portion for attaching the embedded member holder at the end side opposite the embedded member holder, the connecting device has a male threaded portion on its outer surface and a weak portion halfway along its length, the embedded member holder has a male threaded portion for screwing into the embedded member at the end side opposite the embedded member, and a female threaded portion for screwing the male threaded portion of the connecting device into a reduced diameter portion located on the outside of the formwork, and the female threaded portion provided on the embedded member and the male threaded portion provided on the embedded member holder form a connecting portion that connects the two, and the embedded member fixing device can be configured to have a female threaded portion for screwing in the male threaded portion of the connecting device.

[0020] The connector may also have a flange located between the embedment member holder and the embedment member fastener, and the weakened portion may be provided near one side of the flange.

[0021] The embedding member mounting method according to the present invention is a method for holding and mounting an embedding member in a formwork for manufacturing a precast concrete product, and includes the steps of providing an embedding member mounting hole at an embedding member mounting position of the formwork, mounting an embedding member fixing device to the formwork so as to match the embedding member mounting hole, connecting the embedding member and the embedding member holder, fitting the embedding member holder into the embedding member fixing device, and connecting the embedding member holder and the embedding member fixing device using a connector having a fragile part that breaks when an external force of a predetermined level or more is applied, thereby fixing the embedding member holder connected to the embedding member to the formwork. The embedding member holder has an outer peripheral shape that gradually decreases in diameter from the inside to the outside of the formwork, and the embedding member fixing device has an inner peripheral shape that matches the outer peripheral shape of the embedding member holder. It is characterized by the above.

[0022] In the embedment member holding structure and embedment member mounting method having the above-mentioned configuration, the embedment member may be an insert. Effect of the Invention

[0023] According to the embedded member holding structure and embedded member installation method of the present invention, a structure for installing an embedded member to a formwork uses embedded member installation holes provided in the formwork, an embedded member holder for holding the embedded member, and an embedded member fixing device for installing the embedded member holder to the formwork, and the embedded member holder and embedded member fixing device are embedded in the formwork and connected to each other using a connecting device having a fragile part that breaks when an external force greater than a predetermined level is applied.

[0024] Therefore, even if the vibrator comes into contact with the embedded members when pouring concrete into the formwork, the embedded member holder and embedded member fixing device are embedded in the formwork, so the embedded members can resist lateral external forces and will not fall over. In other words, the embedded member holder embedded in the embedded member fixing device resists horizontal forces that try to topple the embedded members while pouring concrete, reducing the force that tries to break the connectors (plastic bolts).

[0025] In addition, when the precast concrete product is removed from the formwork, a tensile force acts on the connecting device (plastic bolt) that connects the embedded member holder and the embedded member fixing device, and the embedded member holder embedded in the embedded member fixing device does not resist the tensile force, so the connecting device (plastic bolt) breaks at the weak part, and the product can be easily removed from the formwork.

[0026] The embedded member retaining structure and embedded member installation method of the present invention achieve the above-mentioned effects, and therefore, even in the case of large embedded members, the embedded members can be securely held against the formwork when pouring concrete, and can be easily removed when the precast concrete product is demolded.

[0027] Furthermore, even in cases where there is no extra space outside the formwork and it is difficult to attach the embedding member holder to the formwork using normal methods, the embedding member can be easily attached to the formwork.

[0028] In addition, the embedding members, the embedding member holders, and the embedding member fasteners are all connected by screw structures, which also makes it easy to attach the embedding members to the formwork. After demolding, the embedding members and the embedding member holders can be easily separated. [Brief description of the drawings]

[0029] [Figure 1] 1 is a vertical cross-sectional view showing an embedding member holder, an embedding member fixing device, and a connecting device used in an embedding member holding structure and an embedding member mounting method according to an embodiment of the present invention, attached to a formwork. [Diagram 2] 1A is a schematic longitudinal sectional view and FIG. 1B is a bottom view of an embedding member holder and a connector used in an embedding member holding structure and an embedding member mounting method according to an embodiment of the present invention. [Diagram 3] 1A to 1C are schematic diagrams of an embedding member, an embedding member holder, and a connector used in an embedding member holding structure and an embedding member mounting method according to an embodiment of the present invention. [Figure 4] 4 is a flowchart showing the steps of a method for attaching an embedded member according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embedding member holding structure and an embedding member mounting method according to an embodiment of the present invention will be described with reference to the drawings. Figures 1 to 4 are for explaining an embedding member holding structure and an embedding member mounting method according to an embodiment of the present invention, in which Figure 1 is a vertical cross-sectional view showing an insert holder (embedded member holder), an insert fixing device (embedded member fixing device), and a connecting device mounted on a formwork, Figure 2 is a vertical cross-sectional schematic view and a bottom view of the insert holder (embedded member holder) and the connecting device, Figure 3 is a schematic view of the insert (embedded member), the insert holder (embedded member holder), and the connecting device, and Figure 4 is a flow chart showing the steps of the insert mounting method (embedded member mounting method).

[0031] <Outline of embedded member retention structure> In the following description, an insert will be taken as an example of a typical embedding member, but the present invention can also be applied to embedding members such as grout injection ports in addition to inserts. An insert holding structure (embedded member holding structure) according to an embodiment of the present invention is a structure for holding an insert (embedded member) in a formwork for manufacturing precast concrete products, and its main components include an insert holder (embedded member holder) for holding the insert (embedded member) and an insert fixing device (embedded member fixing device) for fixing the insert holder (embedded member holder) to the formwork. Materials Fixture), insert holder (embedded member holder) and insert fixture (embedded Materials and a connecting device for connecting the fixing device to the fixing member.

[0032] The present invention can be applied to the manufacture of precast concrete products for various applications, such as shield segments, culverts, floor panels, etc. Shield segment inserts are used for suspending belt conveyors, attaching electric cable racks, attaching ventilation fans, attaching guide plates, etc., and the present invention can be suitably applied to inserts with large diameters (e.g., diameters of 20 mm to 22 mm) and long lengths (e.g., lengths of 150 mm).

[0033] <Formwork> Although not shown, the formwork includes, for example, a bottom plate, side plates rising from the periphery of the bottom plate, and a top plate that is attached to the upper surface of the formwork to seal the formwork. The upper part above the bottom plate is the inside side of the formwork, and the back surface (lower surface) of the bottom plate and the outer surfaces of the side plates are the outside sides of the formwork. In addition, the bottom plate of the formwork 50 of this embodiment is provided with an insert mounting hole 51 at a position where the insert 10 is to be attached. As will be described in detail later, an insert fixing device 30 is attached to the back surface of the bottom plate of the formwork 50 opposite the insert mounting hole 51.

[0034] <insert> The insert 10, which is the embedded member of this embodiment, is larger in diameter and longer than a general insert 10. Note that the present invention can be applied not only to such a large-diameter and long-length insert 10 but also to a general insert 10. in As shown in Fig. 3, the insert 10 uses, for example, a deformed steel bar (deformed reinforcing bar), which is a rod-shaped steel material having uneven protrusions called "ribs" or "nodes" on its surface.

[0035] The insert 10 is provided with a retaining female screw portion 11 for attaching the insert holder 20 on the end side facing the insert holder 20. In this embodiment, an attachment hole is drilled along the length direction of the deformed steel bar, and the retaining female screw portion 11 is provided inside this attachment hole.

[0036] <Insert holder> As shown in FIGS. 1 to 3, the insert holder 20 is inserted into the mold 50 from the inside of the mold 50. External side The insert fixing tool 30 has an outer peripheral shape that gradually tapers toward the outer peripheral surface of the insert holder 20. In this embodiment, the inner peripheral surface of the insert fixing tool 30 and the outer peripheral surface of the insert holder 20 are cone-shaped and come into contact with each other. Since the inner peripheral surface of the insert fixing tool 30 and the outer peripheral surface of the insert holder 20 have such shapes, positioning can be easily performed when fitting the insert holder 20 into the insert fixing tool 30.

[0037] That is, for example, if the inner peripheral surface of the insert fixing tool 30 is cylindrical and the insert holder 20 is columnar, accurate positioning is required when fitting the insert holder 20 into the insert fixing tool 30. On the other hand, if the inner peripheral surface of the insert fixing tool 30 and the outer peripheral surface of the insert holder 20 are cone-shaped and in contact with each other, if a part of the outer peripheral surface of the insert holder 20 comes into contact with any position on the inner peripheral surface of the insert fixing tool 30, Insert holder 20 Since the outer peripheral surface (the inclined surface that reduces in diameter) of the insert holder 20 is guided to the inner peripheral surface (the inclined surface that reduces in diameter) of the insert fixing device 30 and the position is automatically adjusted, the insert holding device 20 can be easily fitted into the inside of the insert fixing device 30.

[0038] Furthermore, the insert holder 20 is provided with a retaining male screw portion 21 for screwing into the retaining female screw portion 11 of the insert 10 at its end side (expanded diameter end) facing the insert 10. The insert holder 20 of this embodiment is provided with a protrusion 22 for insertion into a mounting hole drilled inside the insert 10 at its end side (expanded diameter end) facing the insert 10, and a retaining male screw portion 21 that matches the retaining female screw portion 11 provided in the mounting hole drilled in the insert 10 is provided on the outer circumferential surface of this protrusion 22. This allows the insert 10 and the insert holder 20 to be connected.

[0039] Further, the insert holder 20 has a mounting hole for inserting the connector 40 in a reduced diameter portion located on the outside of the formwork 50, and a first connecting female screw portion 23 that matches the connecting male screw portion 41 of the connector 40 is provided inside the mounting hole. This allows the connector 40 to be attached to the insert holder 20.

[0040] Furthermore, the insert holder 20 has a notch 24 for engaging a tool such as a wrench in a reduced diameter portion located on the outside of the mold 50. When attaching or detaching the insert holder 20 to or from the insert 10, the insert holder 20 can be easily attached or detached to or from the insert 10 by engaging a tool such as a wrench in the notch 24 and manipulating (rotating) the insert holder 20.

[0041] <Insert Fixture> 1, the insert fixing tool 30 has an inner peripheral shape that matches the outer peripheral shape of the insert holder 20, and is a member for attaching and fixing the insert holder 20 to the formwork 50 with the insert holder 20 fitted inside. The insert fixing tool 30 is box-shaped with an open top and a mounting hole for the connector 40 provided on the bottom surface, and is attached to the back surface of the bottom plate of the formwork 50 facing the insert mounting hole 51.

[0042] To attach the insert fixing tool 30 to the bottom plate of the formwork 50, the inner diameter enlarged side of the insert fixing tool 30 (the side where the insert holder 20 is inserted) is inserted into the insert mounting hole 51 toward the inner surface of the formwork 50. At this time, the end (upper end surface) of the inner diameter enlarged side of the insert fixing tool 30 and the inner peripheral surface of the bottom plate of the formwork 50 are set to the same height (flush). Then, the outer peripheral surface of the insert fixing tool 30 and the outer surface of the bottom plate of the formwork 50 are welded together. Note that the method of attaching the insert fixing tool 30 to the bottom plate of the formwork 50 is not limited to welding, and an adhesive or the like may be used.

[0043] As described above, the inner surface of the insert fixing device 30 and the outer surface of the insert retainer 20 are cone-shaped and in contact with each other, which makes it easy to position the insert retainer 20 when fitting it inside the insert fixing device 30.

[0044] Further, an attachment hole is formed in the bottom surface of the insert fixing device 30, and a second connecting female thread portion 31 for screwing in the connecting male thread portion 41 of the connecting device 40 is provided on the inner surface of this attachment hole. The insert fixing device 30 and the insert holding device 20 can be connected by screwing one end of the connecting male thread portion 41 provided on the connecting device 40 into the first connecting female thread portion 23 provided on the insert holding device 20, and screwing the other end of the connecting male thread portion 41 provided on the connecting device 40 into the second connecting female thread portion 31 provided on the insert fixing device 30.

[0045] <Connector> 1 to 3, the connector 40 connects the insert holder 20 and the insert fastener 30, and is a rod-shaped member having a fragile part 42 that breaks when a predetermined external force or more is applied, and is made of, for example, polypropylene, polyethylene, etc. As shown in Fig. 3, the connector 40 has a male threaded part 41 on its outer circumferential surface, and has a fragile part 42 midway along its length.

[0046] 3, the connector 40 of this embodiment has a flange portion 43 located between the insert holder 20 and the insert fixing device 30, and the fragile portion 42 is provided near one side of the flange portion 43. The flange portion 43 has a larger diameter than the mounting holes of the connector 40 provided in the insert holder 20 and the insert fixing device 30.

[0047] As described above, one end of the connecting male thread portion 41 provided on the connector 40 is screwed into the first connecting female thread portion 23 provided on the insert holder 20, and the other end of the connecting male thread portion 41 provided on the connector 40 is screwed into the second connecting female thread portion 31 provided on the insert fixture 30, thereby allowing the insert fixture 30 and the insert fixture 20 to be connected. Since the flange portion 43 has a larger diameter than the mounting holes of the connector 40 provided on the insert holder 20 and the insert fixture 30, the connector 40 is divided into two sides, the insert holder 20 side and the insert fixture 30 side, with the flange portion 43 in between. Furthermore, since the weak portion 42 is located near one side of the flange portion 43, when the connector 40 breaks from the weak portion 42 when the precast concrete product is demolded, the broken portion is located near the boundary between the insert holder 20 and the insert fixing device 30, so that the connector 40 can be easily removed from the insert holder 20 and the insert fixing device 30.

[0048] <Connection between insert and insert holder> A connecting portion for connecting the insert 10 and the insert holder 20 is provided between them. In this embodiment, the connecting portion for connecting the insert 10 and the insert holder 20 is constituted by the retaining female screw portion 11 provided on the insert 10 and the retaining male screw portion 21 provided on the insert holder 20.

[0049] <How to attach the insert to the formwork> The formwork 50 can be divided into a plurality of components (plate-like members), and each component can be assembled to form a box-like formwork 50. The components can be assembled, for example, by integrating the components using a hinge mechanism provided on the opposing components, or by fitting a fastener (bolt) provided on one component into a fastening groove provided on the other component and tightening a nut onto the fastener (bolt).

[0050] In this embodiment, the insert 10 is attached and fixed to the inside of the formwork 50 (bottom plate). After the assembly of the formwork 50 is completed, a release agent is applied to the inner surface of the formwork 50 to facilitate demolding, and then concrete is poured and compacted using a vibrator. After a predetermined curing period has elapsed, the formwork is demolded.

[0051] In the method for attaching the insert of this embodiment, as shown in Fig. 4, the insert fixing tool 30 is attached so as to match with the insert fixing hole 51 provided in the formwork 50 (bottom plate) (S1). The insert 10 and the insert holder 20 are connected (S2), the insert holder 20 is fitted into the insert fixing tool 30 (S3), and the insert holder 20 and the insert fixing tool 30 are connected using a connector 40 having a fragile part 42 that breaks when an external force of a predetermined level or more is applied (S4). In this way, the insert holder 20 connected to the insert 10 can be fixed to the formwork 50.

[0052] It should be noted that the step (S2) of connecting the insert 10 and the insert holder 20, the step (S3) of fitting the insert holder 20 into the insert fixing device 30, and the step (S4) of connecting the insert holder 20 and the insert fixing device 30 do not necessarily have to be performed in this order, and can be performed in a different order depending on the shape and structure of the insert 10 (embedded member), etc.

[0053] <Demolding> After pouring concrete into the formwork 50 and curing it for a prescribed period of time, the precast concrete product can be demolded by disassembling the formwork 50. At this time, a tensile force is applied to the connector 40 that connects the insert holder 20 and the insert fixing device 30, so that the connector 40 breaks at the weak portion 42, and the precast concrete product can be easily demolded with the insert 10 remaining in the precast concrete product.

[0054] After demolding is completed, the insert 10 is embedded in the precast concrete product by removing the insert holder 20 from the insert 10. In addition, by removing the connector 40 left on the insert holder 20 and the insert fixture 30, the insert holder 20 and the insert fixture 30 can be reused. [Explanation of symbols]

[0055] 10 Insert 11 Retaining female screw part 20 Insert holder 21 Retention male thread part 22 Protrusion 23 First connecting female screw part 24 Notch 30 Insert Fixture 31 Second connecting female screw part 40 Connector 41 Male threaded connection 42 Weakened part 43 Flange 50 Formwork 51 Insert mounting hole

Claims

1. A retaining structure for retaining an embedded member in a form for producing a precast concrete product, comprising: An embedding member mounting hole provided at a position where the embedding member is to be mounted on the formwork; an embedment member holder having an outer peripheral shape whose diameter gradually decreases from the inside to the outside of the formwork; an embedding member fixing device that is attached to the embedding member mounting hole, has an inner peripheral shape that matches an outer peripheral shape of the embedding member holder, and is attached and fixed to a formwork in a state in which the embedding member holder is fitted inside; a connector that connects the embedment member holder and the embedment member fixing device and has a fragile part that breaks when a predetermined external force or more is applied; a connecting portion provided between the embedding member and the embedding member holder and connecting the two; 1. A structure for retaining embedded members in a formwork for manufacturing precast concrete products, comprising:

2. The inner peripheral surface of the embedment member fixing tool and the outer peripheral surface of the embedment member holding tool are in contact with each other to form a cone shape.

2. The method of claim 1, wherein the precast concrete product is formed by a precast concrete structure.

3. the embedding member has a female screw portion for attaching the embedding member holder at an end side facing the embedding member holder, The connector has a male thread on its outer circumferential surface and a fragile portion midway along its length, The embedding member holder has a male screw portion for screwing into the embedding member at an end side facing the embedding member, and has a female screw portion for screwing into the male screw portion of the connector at a reduced diameter portion located on the outer side of the formwork, a female screw portion provided on the embedding member and a male screw portion provided on the embedding member holder constitute a connecting portion that connects the two together, The embedding member fixing device has a female thread portion into which the male thread portion of the connecting device is screwed.

3. A structure for retaining embedded members in a formwork for manufacturing precast concrete products according to claim 1 or 2.

4. the connector has a flange portion located between the embedment member holder and the embedment member fixing device, and the fragile portion is provided near one side of the flange portion; 4. A structure for retaining embedded members in a formwork for manufacturing precast concrete products according to claim 1.

5. The embedding member is an insert.

5. A structure for retaining embedded members in a formwork for manufacturing precast concrete products according to any one of claims 1 to 4.

6. 1. A method for mounting an embedment member to a form for manufacturing a precast concrete product, comprising: providing an embedding member mounting hole at a mounting position of the formwork for the embedding member; a step of attaching an embedment member fastener to the formwork so as to match the embedment member attachment hole; connecting the embedding member and an embedding member holder; fitting the implant member holder into the implant member fastener; a step of connecting the embedment member holder and the embedment member fixing device using a connector having a fragile portion that breaks when a predetermined external force or more is applied, thereby fixing the embedment member holder connected to the embedment member to the formwork; Including, A method for installing embedded members in a formwork for manufacturing precast concrete products, characterized in that the embedded member holder has an outer peripheral shape that gradually narrows from the inside to the outside of the formwork, and the embedded member fixing device has an inner peripheral shape that matches the outer peripheral shape of the embedded member holder.

Images