Reinforcing bar cage

Abstract

To provide a low-cost reinforcing bar cage etc. equipped with a simple connecting rotation jig having sufficient strength.SOLUTION: A reinforcing bar cage is a telescopic type having a cylindrical cage body in which a hoop and a flexible strand 21 are joined so that the crossing angle is variable. In the reinforcing bar cage of the present invention, a plurality of reinforcing rings 4 along the circumferential direction of the cage body are arranged at intervals in the axial direction of the cage body, and a fixing part 20 including a crimping grip 24 and a support plate 25 is provided at an end of the strand 21. The strand 21 and the reinforcing ring 4 are joined by a connecting rotation jig 5 located at a position a predetermined distance L away from the crimping grip 24 so that the crossing angle is variable. The connecting rotation jig 5 has a sleeve through which the strand 21 passes, a filler filled between the sleeve and the strand 21, a nut provided on the side of the sleeve, and a bolt that passes through a hole in the reinforcing ring 4 and screws into the nut.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to telescoping reinforcing bars and the like. [Background technology]

[0002] A typical reinforced concrete cage for a cast-in-place concrete pile has multiple axial steel members spaced around the periphery of the cage body and hoops surrounding them, but there are also telescoping reinforcement cages that make it easier to transport and install.

[0003] Fig. 10(a) is a diagram showing a telescopic reinforcing bar cage 100. This reinforcing bar cage 100 uses flexible PC steel strands (hereinafter referred to as strands) 21 as the axial steel material constituting the cage body 2 instead of ordinary deformed reinforcing bars.

[0004] In the cage body 2, the strands 21 and the ties 22 are connected at their intersections by a connecting rotation jig so that the crossing angle between the strands 21 and the ties 22 is variable, and by twisting the upper end of the cage reinforcing bar 100 as shown by arrow A, the cage reinforcing bar 100 contracts as shown in Figures 10(b) and (c). On the other hand, by rotating the upper end of the cage reinforcing bar 100 in the direction opposite to arrow A as shown by arrow B in Figure 10(c), the cage reinforcing bar 100 expands. Examples of the above connecting rotation jig are described in Patent Documents 1 to 3.

[0005] In addition, reinforcing rings 4 are arranged at the upper and lower ends and in the middle of the reinforcing bar cage 100, just like in a normal reinforcing bar cage, and the reinforcing rings 4 and strands 21 are also connected by a connecting rotating jig similar to that described above. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2005-048519 A [Patent Document 2] JP 2006-132190 A [Patent Document 3] JP 2008-214990 A Summary of the Invention [Problem to be solved by the invention]

[0007] When the reinforcing bar cage 100 is contracted, bending and twisting occur in the strands 21, but the connecting rotation jig at the upper end of the reinforcing bar cage 100 restrains these deformations (bending and twisting). The connecting rotation jig is designed to be able to bear the load associated with the restraint, and in a normal reinforcing bar cage 100, the strands 21 are connected to the reinforcing ring 4 at the upper end by this connecting rotation jig. However, when a strand 21 with high bending rigidity or torsional rigidity is used, the strength of the connecting rotation jig is insufficient, and in particular, there is a risk that the force acting on the rotation axis thereof may become excessive. On the other hand, if an attempt is made to improve the strength of the connecting rotation jig, the structure becomes larger and more complicated, which leads to increased costs.

[0008] The reinforcing bar cage 100 is placed while being extended in a drilled hole (not shown) provided in the ground, and is fixed to the concrete at the pile head by an anchoring portion formed by fastening nuts to the top and bottom of a bearing plate passed through the apartment 23 at the upper end of the strand 21. The bearing plate can be attached after the reinforcing bar cage 100 is extended, and has the advantage that it does not need to be attached to the reinforcing bar cage 100 in advance. However, the apartment 23 is expensive, which causes the cost of the reinforcing bar cage 100 to increase.

[0009] The present invention has been made in consideration of the above problems, and has an object to provide a low-cost reinforcing bar cage or the like equipped with a simple connecting rotation jig having sufficient strength. [Means for solving the problem]

[0010] The first invention for solving the above-mentioned problems is an expandable reinforcing bar cage having a cylindrical cage in which a hoop and a flexible strand are connected so that the crossing angle is variable, wherein a plurality of reinforcing rings aligned along the circumferential direction of the cage are arranged at intervals in the axial direction of the cage, and a fixing portion including a crimping grip and a support plate provided on the base side of the crimping grip is provided at the end of the strand, and the strand and the reinforcing ring or the hoop at the upper end of the reinforcing bar cage are connected so that the crossing angle is variable by a connecting rotation jig located a predetermined distance away from the crimping grip, and the connecting rotation jig has a sleeve through which the strand passes, a filler material filled between the sleeve and the strand, a female threaded portion provided on the side of the sleeve, and a bolt that screws into the female threaded portion and functions as a rotation axis when the strand and the reinforcing ring or the hoop rotate relative to each other.

[0011] In the present invention, by using the above-mentioned connecting rotation jig consisting of the sleeve, bolt, etc., the connecting rotation jig becomes simple and has sufficient strength, and it is possible to use a strand with high bending rigidity and torsional rigidity. In addition, by using a crimping grip that is commonly used at the fixed end of a normal tendon as the anchoring part of the strand, the rebar cage can be configured at low cost. Furthermore, when using a crimping grip as the anchoring part, it is necessary to attach a support plate to the strand in advance, but in the present invention, by ensuring the necessary distance between the crimping grip and the connecting rotation jig, it is possible to prevent the support plate from interfering with the reinforcing ring or the tie bars when the rebar cage contracts.

[0012] For example, the coupling rotation jig couples the strand and the reinforcing ring, and the bolt is passed through a hole in the reinforcing ring. In the present invention, the connecting and rotating jig for the reinforcing ring at the upper end of the reinforcing cage can be simplified and made smaller, and its size can be adjusted to match the dimensions of the connecting and rotating jig for the reinforcing rings other than the upper end, which makes it easier to manufacture the reinforcing cage.

[0013] The predetermined distance is, for example, 12 times or more the diameter of the strand. This prevents the local stress applied to the strand portion near the crimping grip when the strand is subjected to tension from being superimposed on the local stress inside the sleeve due to bending and twisting of the strand near the connecting rotation jig, thereby preventing damage to the filler inside the sleeve, etc.

[0014] It is also preferable that the cage further includes a connecting member that connects the anchoring portions of the strands in the circumferential direction of the cage body of the contracted reinforcing bar cage and draws the anchoring portions inward. This prevents the anchoring parts from protruding outward when the reinforcing bar cage is in a contracted state, facilitating transportation of the reinforcing bar cage, etc. In addition, the connecting material resists bending of the strands that occurs when the reinforcing bar cage contracts, reducing the load on the connecting rotation jig and enabling the connecting rotation jig to be further simplified and made smaller.

[0015] It is preferable that the fixing portion has a pressing member for tightly contacting the pressure grip with the support plate. This allows the pressure grip to be tightly attached to the support plate, improving the fixing effect of the fixing portion.

[0016] It is desirable that the support plate has a rectangular planar shape and is disposed so that its long side is aligned with the radial direction of the cage body. This makes it possible to prevent interference between the support plate attached to the strand and the adjacent strand when the reinforcing bar cage is contracted. Effect of the Invention

[0017] According to the present invention, it is possible to provide a low-cost reinforcing bar cage or the like equipped with a simple connecting rotation jig having sufficient strength. [Brief description of the drawings]

[0018] [Figure 1] A diagram showing a reinforcing bar cage 1. [Diagram 2] FIG. 2 is a cross-sectional view of a strand 21. [Diagram 3] FIG. 2 is a diagram showing the upper end of the strand 21. [Figure 4] FIG. [Diagram 5] A top view of the upper end of the reinforcing bar cage 1 in a contracted state. [Figure 6] A diagram showing the heights H, H1, and H2 of the inner edges of the inner reinforcing ring 4 of the reinforcing bar cage 1. [Figure 7] A diagram showing reinforcing bars 8. [Figure 8] An example of using the support plate 25 vertically. [Figure 9] FIG. 2 is a diagram showing support plates 25a, 25b, and 25b'. [Figure 10] FIG. 1 shows a telescopic rebar cage 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0020] Fig. 1 shows a reinforcing bar cage 1 according to an embodiment of the present invention, Fig. 1(a) is a view of the reinforcing bar cage 1 seen from the outside, and Fig. 1(b) is a view of the inside of the reinforcing bar cage 1. The reinforcing bar cage 1 of this embodiment is inserted into a borehole provided in the ground, and concrete is poured into the borehole to be used as a reinforcing material for a cast-in-place concrete pile, but is not limited thereto.

[0021] The reinforcing bar cage 1 is of an expandable type, like the reinforcing bar cage 100, and has a cage body 2 in which strands 21, which are flexible axial steel materials, and ties 22 are connected by a connecting rotation jig (not shown) so that the crossing angle is variable. Figures 1(a) and (b) show the cage body 2 in an expanded state.

[0022] 2 is a diagram showing a cross section of the strand 21. The strand 21 is formed by twisting a plurality of wires 211 in a spiral shape. In this embodiment, a high-strength strand having a diameter R of 17.8 mm and high bending rigidity and torsional rigidity is used as the strand 21, but the present invention is not limited to this.

[0023] A plurality of strands 21 are arranged at intervals in the circumferential direction of the cage body 2, and a plurality of hoops 22 are arranged at intervals in the axial direction of the cage body 2. Reinforcing rings 4 are provided on both the inside and outside of the cage body 2. A plurality of reinforcing rings 4 are arranged at intervals in the axial direction of the cage body 2 at both ends of the cage body 2 in the axial direction and at an intermediate portion between both ends.

[0024] An anchoring portion 20 is provided at the upper end of the strand 21 for anchoring the strand 21 to the concrete at the pile head of a cast-in-place concrete pile. Fig. 3 is a diagram showing the upper end of the strand 21, and the anchoring portion 20 has a pressure grip 24, a bearing plate 25, a pressing member 26, etc. In the following explanation, "upper" and "lower" correspond to the upper and lower sides of the reinforcing bar cage 1 in use, and when the reinforcing bar cage 1 is used for a cast-in-place concrete pile, the pile head side is the "upper".

[0025] The crimping grip 24 is a known tubular member commonly used at the fixed end of an ordinary tension member (see, for example, Japanese Patent Nos. 7219851 and 7113120), and is attached to the upper end of the strand 21.

[0026] The support plate 25 is a rectangular plate material provided on the base side of the crimping grip 24, and is arranged with its long side aligned with the radial direction of the cage body 2 (corresponding to the left-right direction in FIG. 3). The support plate 25 is attached with the strand 21 passing through its hole. The base side refers to the center side in the axial direction of the strand 21, and corresponds to the lower side in FIG. 3.

[0027] The crimping grip 24 is disposed so that its base end is in close contact with the plate surface of the support plate 25, and the pressing member 26 presses the crimping grip 24 toward the support plate 25, thereby maintaining the close contact between the crimping grip 24 and the support plate 25. The pressing member 26 in this embodiment is a U-bolt, both ends of which penetrate the support plate 25, and a nut 27 is fastened to the tip of the U-bolt protruding from the support plate 25.

[0028] The reinforcing ring 4 is a ring-shaped steel material having an L-shaped cross section composed of a vertical portion 41 and a horizontal portion 42, and is arranged along the circumferential direction of the cage body 2. The reinforcing ring 4 can be formed, for example, by processing an angle bar into a ring shape. The reinforcing ring 4 on the inside of the cage body 2 is arranged so that the horizontal portion 42 protrudes inward, and the reinforcing ring 4 on the outside of the cage body 2 is arranged so that the horizontal portion 42 protrudes outward. "Inside" refers to the center side of the plane of the cage body 2, and "outside" refers to the opposite side.

[0029] The strands 21 and the inner and outer reinforcing rings 4 are connected so that the crossing angle is variable, using a connecting rotation jig 5. Figure 4 is a diagram showing the connecting rotation jig 5, and shows a cross section of the connecting rotation jig 5 taken along the axial direction of the strands 21.

[0030] The connecting rotation jig 5 has a pair of nuts 52 (female threaded portions) fixed to the side of a sleeve 51 through which the strand 21 is inserted, and the connecting rotation jig 5 can be attached to the inner and outer reinforcing rings 4 by screwing headed bolts 53 passed through holes 411 in the vertical parts 41 of the inner and outer reinforcing rings 4 into each nut 52.

[0031] The sleeve 51 is a cylinder made of a steel pipe or the like, and the nut 52 is fixed to the sleeve 51 by welding or the like. The gap between the sleeve 51 and the strand 21 is filled with a filler 54 made of a solidifying material such as resin. This fixes (holds) the strand 21 to the sleeve 51, and the strand 21 and the inner and outer reinforcing rings 4 are joined so as to be capable of relative rotation with the bolt 53 as the rotation axis. Note that the nut 52 may be provided with an O-ring, a disc spring, or the like on the end face on the bolt insertion side to provide an anti-loosening function for the bolt 53.

[0032] The joining rotation jig 5 is disposed at a position a predetermined distance L (see FIG. 3) away from the crimping grip 24. This distance L is at least 12 times the diameter R (see FIG. 2) of the strand 21, and more preferably 18 times or more.

[0033] The strand portion near the crimping grip 24 is subjected to local stress when the strand 21 is subjected to tension, and there is a concern that the strength of the strand portion may decrease when the strand 21 is subjected to repeated loads. Therefore, the above distance L is determined so that the local stress in the sleeve 51 caused by bending and twisting of the strand 21 near the connecting rotation jig 5 does not overlap with the above local stress.

[0034] The distance L ensures at least the pitch of the twist of the strand 21, that is, the distance (for example, about 300 to 400 mm) required for one wire 211 to make one revolution around the cross section of the strand 21. Therefore, the stress of the wires 211 is uniformed among the wires 211 of the strand 21 due to friction between the wires 211. When a wire material in which the wires 211 are twisted, such as the strand 21, is bent, the wires 211 pass through the outside and inside of the bent strand 21 while the twist makes one revolution, and the wires 211 are stretched on the outside and compressed on the inside, but the wires 211 slide freely against each other, so that the axial force of the wires 211 tends to become zero both on the outside and inside. As a result, the wires 211 of the strand 21 can be easily bent without plastic deformation. The twist pitch of strand 21, that is, the length required for one turn of twist, is 12 to 18 times the strand diameter. From the above viewpoint, it is preferable that distance L is at least 12 times or more than diameter R of strand 21.

[0035] 5(a) is a top view of the upper end of the reinforcing bar cage 1 in a contracted state. In this embodiment, the connecting rotation jig 5 at the upper end of the reinforcing bar cage 1 restrains bending of the strand 21, so that the strand 21 extends in a straight line from there to the tip, and the anchoring portion 20 protrudes radially outside the reinforcing bar cage 1. Therefore, there is a concern that the reinforcing bar cage 1 may interfere with the sidewall of the truck when transporting the reinforcing bar cage 1 by truck, making transportation difficult, or that space may be required for storing the reinforcing bar cage 1.

[0036] Therefore, in this embodiment, as shown in Fig. 5(b), pressing members 26 (U-bolts) of anchoring parts 20 of multiple strands 21 are mutually connected by connecting materials 3 such as strings or wires, and the tip portions of the strands 21 are bent inward to draw the anchoring parts 20 inward, so that the anchoring parts 20 do not spread radially when the reinforcing bar cage 1 is contracted. This allows the anchoring parts 20 to be stored inward, and also makes it possible to make the position of the crimping grips 24 in the radial direction of the reinforcing bar cage 1 the same as when the reinforcing bar cage 1 is fully extended.

[0037] Connection using the connecting material 3 may be performed by tying the pressing members 26 of the fixing parts 20 at opposing positions in the radial direction of the reinforcing bar cage 1 with a connecting material 3 such as a string, as shown in Figure 5(b), or may be performed by tying the pressing members 26 of all the fixing parts 20 in a complete circle with the connecting material 3, as shown in Figure 5(c).

[0038] In addition to the pressing member 26, the crimping grip 24 and the support plate 25 are also rigid, so the connecting material 3 can be attached to these members. If the connecting material 3 is made even shorter, the fixing portion 20 can be pushed further inward, and the outer end of the support plate 25 can be positioned at the same position as the outer edge of the outer reinforcing ring 4 or further inward, which is suitable for transporting the reinforcing bar cage 1 in a contracted state.

[0039] In addition, because the connecting material 3 resists bending of the strand 21, the bending acting on the connecting rotation jig 5 at the upper end when the rebar cage 1 contracts is greatly reduced, and the connecting rotation jig 5 only needs to bear the reaction force when the strand 21 is twisted. Therefore, the strength required for the connecting rotation jig 5 can be greatly reduced, making it possible to reduce the diameter of the rotating shaft (bolt 53), reduce the grade of the material, and shorten the length of the sleeve 51.

[0040] This is also effective when transporting and storing the shrunken rebar cage 1. That is, the rebar cage 1 is usually assembled in a factory, shrunken, and transported by truck to the construction site. It may be stored for several months, during which time the connecting rotating jig 5 is constantly bent and twisted in its shrunken state, and there is a risk that the filler 54, such as resin, will be destroyed by creep deformation and lose its gripping function. However, by connecting the cage with the connecting material 3, the bending action is almost eliminated, and the gripping function of the strand 21 can be reliably maintained.

[0041] 6(a), the reinforcing bar cage 1 is manufactured in a factory or the like in a horizontally extended state, and then the reinforcing bar cage 1 is twisted to shrink it, but this shrinking work is performed with a suspension steel pipe 6 passing through the inside of the reinforcing bar cage 1 and the entire reinforcing bar cage 1 suspended via the suspension steel pipe 6. Therefore, with the reinforcing bar cage 1 held horizontally, it is necessary to align the height H of the inner edge of the reinforcing ring 4 on the inside of the reinforcing bar cage 1 that abuts against the suspension steel pipe 6.

[0042] Conventionally, the connecting rotation jig 5 used for the reinforcing ring 4 at the pile head has been enlarged to increase its strength, and as a result, among the reinforcing rings 4 inside the reinforcing bar cage 1, the reinforcing ring 4 at the pile head has the smallest diameter. As a result, as shown in FIG. 6(b), when the reinforcing bar cage 1 is held horizontal, the heights H1, H2 of the inner edges of the reinforcing ring 4 at the pile head and the other reinforcing rings 4 are not aligned, which causes problems in supporting the reinforcing bar cage 1 with the suspension steel pipe 6. Therefore, in order to align the height of the inner edges of the reinforcing ring 4 at the pile head, it was necessary to space the other reinforcing rings 4 away from the strands 21 more than necessary (by placing a spacer or the like between the reinforcing ring 4 and the strands 21).

[0043] In addition, with regard to the reinforcing ring 4 on the outside of the reinforcing bar cage 1, the connecting rotating jig 5 used for the reinforcing ring 4 at the pile head became larger, making it necessary to use reinforcing rings 4 of different dimensions for the pile head and the other reinforcing rings 4.

[0044] In contrast, according to this embodiment, the connecting rotation jig 5 used for the reinforcing ring 4 at the pile head can be simplified and made smaller, so that the dimensions can be made similar to those of the connecting rotation jig 5 used for the other reinforcing rings 4, and it is also possible to unify the diameters of the sleeves 51 and bolts 53. As a result, for the reinforcing rings 4 on the inside of the reinforcing cage 1, there is no need to ensure an excessive distance between the strands 21 and the reinforcing rings 4 other than those at the pile head. Also, for the reinforcing rings 4 on the outside of the reinforcing cage 1, the dimensions of the reinforcing ring 4 at the pile head and the other reinforcing rings 4 can be unified. This makes it easier to manufacture the reinforcing cage 1.

[0045] The reinforcing bar cage 1 is extended and placed in the borehole 10 as shown in Fig. 7, and the reinforcing bar 8 is placed near the lower side of the bearing plate 25. Thereafter, concrete (not shown) is poured into the borehole 10 to form a cast-in-place concrete pile. The reinforcing bar 8 is, for example, a grid-shaped bar (grid bar), but is not limited to this. The reinforcing bar 8 can also be attached to the reinforcing bar cage 1 in advance.

[0046] In conventional reinforcing bar cages, the anchoring part of the strand 21 is assembled by inserting the support plate into the apartment building and attaching a nut, and then placing the reinforcing bar 8 on the back of the support plate. At this time, since the apartment building and the reinforcing ring 4 at the pile head are close to each other, there are cases where the reinforcing ring 4 must be removed. On the other hand, according to this embodiment, the support plate 25 and the reinforcing ring 4 at the pile head are sufficiently separated, so after the extension of the reinforcing bar cage 1 is complete, the assembly of the anchoring part is completed simply by placing the reinforcing bar 8 on the back of the support plate 25, and there is no need to remove the reinforcing ring 4 at the pile head.

[0047] As described above, in this embodiment, by using the connecting rotation jig 5 consisting of the sleeve 51, the bolt 53, etc., the connecting rotation jig 5 is simple and has sufficient strength, and it is possible to use the strand 21 having high bending rigidity and torsional rigidity. In addition, by using the crimping grip 24, which is commonly used at the fixed end of a normal tendon, as the fixing part 20 of the strand 21, the reinforcing bar cage 1 can be configured at low cost. Furthermore, when the crimping grip 24 is used as the fixing part 20, the support plate 25 needs to be attached to the strand 21 in advance, but by ensuring a necessary distance between the crimping grip 24 and the connecting rotation jig 5, it is possible to prevent the support plate 25 from interfering with the reinforcing ring 4 when the reinforcing bar cage 1 contracts.

[0048] In particular, in this embodiment, by making the above-mentioned separation distance L 12 times or more the diameter R of the strand 21, it is possible to prevent the local stress applied to the strand portion near the crimping grip 24 when the strand 21 is subjected to tension from being superimposed on the local stress inside the sleeve 51 due to bending and twisting of the strand 21 near the connecting rotation jig 5, and to prevent damage to the filler 54 inside the sleeve 51, etc.

[0049] In this embodiment, the connecting rotation jig 5 for the reinforcing ring 4 at the upper end of the reinforcing bar cage 1 can be simplified and made smaller, and its size can be adjusted to match the dimensions of the connecting rotation jig for the reinforcing rings 4 other than the upper end. This makes it easier to manufacture the reinforcing bar cage 1.

[0050] In addition, in the fixing section 20 of this embodiment, the pressing member 26 brings the pressure grip 24 into close contact with the support plate 25, thereby enhancing the fixing effect of the fixing section 20.

[0051] In this embodiment, the connecting material 3 is used to pull the anchoring portion 20 of the contracted cage reinforcing bar 1 inward, preventing the anchoring portion 20 from protruding outward in the contracted cage reinforcing bar 1 and facilitating transportation of the cage reinforcing bar 1. In addition, the connecting material 3 resists bending of the strands 21 that occurs when the cage reinforcing bar 1 contracts, reducing the load on the connecting rotation jig 5 and enabling the connecting rotation jig 5 to be further simplified and made smaller.

[0052] However, the present invention is not limited to the above embodiment. For example, the configuration of the coupling rotation jig 5 is not limited to the above. As an example, in this embodiment, the bolt 53 is screwed into the female thread of the nut 52 fixed to the sleeve 51, but the female thread portion into which the bolt 53 is screwed can also be formed directly on the side surface of the sleeve 51, etc.

[0053] In this embodiment, the rectangular support plate 25 is arranged with its long side aligned with the radial direction of the cage body 2 (called "horizontal use"). However, as shown in Fig. 8(a), the rectangular support plate 25 may be arranged with its long side aligned with the circumferential direction of the cage body 2 (called "vertical use"). The circumferential direction of the cage body 2 corresponds to the normal direction to the paper surface of Fig. 8(a).

[0054] The direction of the support plate 25 may be determined depending on the configuration of the reinforcing bar cage 1 (such as the number of strands 21) and whether the reinforcing bar cage 1 can be transported by truck. For example, Fig. 8(b) is a diagram showing the case where the support plate 25 is used horizontally and the case where it is used vertically near the reinforcing ring 4 at the upper end of the contracted reinforcing bar cage 1, and in the above embodiment, by using the support plate 25 horizontally, it is possible to suppress interference between the support plate 25 attached to a strand 21 and the strand 21 adjacent to that strand 21 when the reinforcing bar cage 1 is contracted.

[0055] On the other hand, if the support plate 25 is used vertically, there is an advantage that the support plate 25 is less likely to protrude outside the reinforcing bar cage 1 when the reinforcing bar cage 1 is in a contracted state. However, as can be seen from Figure 8(b), the above-mentioned interference is more likely to occur when the reinforcing bar cage 1 is contracted.

[0056] In order to avoid this interference, as shown in the support plate 25a in FIG. 9(a), in addition to the hole 251 for passing the strand 21, a notch 252 for passing the adjacent strand 21 may be provided. Also, as shown in the support plate 25b in FIG. 9(b), a slit 253 having both the functions of the hole 251 and the notch 252 may be formed. In FIG. 9(b), the slit 253 is formed along the long side direction of the support plate 25b at the center of the short side direction of the support plate 25b, but as shown in the support plate 25b' in FIG. 9(c), the slit 253 may be formed along the short side direction of the support plate 25b' at the center of the long side direction of the support plate 25b'. Also, the planar shape of the support plate 25 may be a shape other than a rectangle that can appropriately avoid the above-mentioned interference.

[0057] In these cases, however, the strength of the support plates 25, 25a, 25b, and 25b' may decrease, so sufficient consideration must be given to the strength of the support plates 25, 25a, 25b, and 25b'. Even when the support plate 25 is used horizontally, it is possible to form the notches 252 and slits 253 described above.

[0058] The configuration of the reinforcing bar cage 1 is not limited to the above. For example, the connecting rotation jig 5 may connect the strand 21 and the hoop 22 at the upper end of the reinforcing bar cage 1 so that the cross angle is variable. In this case, a short angle bar having a hole for passing a bolt 53 is attached to the hoop 22.

[0059] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the above examples. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0060] 1, 100: Reinforced concrete cage 2:Cage body 3: Connecting material 4: Reinforcement ring 5: Joint rotation jig 20: Fixing section 21: Strand 22: Stitching 23: Apartment 24: Crimping grip 25, 25a, 25b, 25b': Support plate 26: Pressing member 51: Sleeve 52: Nut 53: Bolt 54: Filling material

Claims

1. A retractable reinforcing bar cage having a cylindrical cage body in which a hoop and a flexible strand are connected so that the cross angle is variable, A plurality of reinforcing rings are arranged along the circumferential direction of the cage at intervals in the axial direction of the cage, A fixing portion including a crimping grip and a support plate provided on a base side of the crimping grip is provided at the end of the strand, The strand and the reinforcing ring or the tie at the upper end of the reinforcing bar cage are connected to each other by a connecting rotation jig located at a predetermined distance from the crimping grip so that the crossing angle can be changed; The coupling rotation jig is a sleeve through which the strand passes; A filler material is filled between the sleeve and the strand; A female thread portion provided on a side surface of the sleeve; A bolt that is screwed into the female threaded portion and functions as a rotation axis when the strand and the reinforcing ring or the hoop rotate relative to each other; A reinforcing bar cage comprising:

2. the connecting rotation jig connects the strand and the reinforcing ring, 2. The rebar cage of claim 1, wherein the bolts pass through holes in the reinforcing ring.

3. 2. The reinforcing bar cage of claim 1, wherein the predetermined distance is greater than or equal to 12 times the diameter of the strand.

4. 2. The reinforcing bar cage according to claim 1, further comprising a connecting member that connects the anchoring portions of the strands in the circumferential direction of the cage body of the contracted reinforcing bar cage and pulls the anchoring portions inward.

5. 2. The reinforcing bar cage according to claim 1, wherein the fixing portion has a pressing member for tightly contacting the pressure grip with the support plate.

6. 2. The reinforcing bar cage according to claim 1, characterized in that the plane of the support plate is rectangular and the long side direction is arranged in the radial direction of the cage body.

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